TWI619600B - Biaxially oriented polyester film for demolding - Google Patents

Abstract

The object of the invention is to improve the coating property of the ceramic slurry and the green sheet laminate property at the time of molding the green sheet.

The solution is a biaxially oriented polyester film for demolding, which comprises three layers, having a surface layer (layer A), an intermediate layer (layer B), and a surface layer (layer C), wherein: layer A contains relative to layer A. The inorganic particles and/or organic particles having a volume average particle diameter (dA) of 0.05% by weight or more and 1.0% by weight or less of 0.1 μm or more and 1.0 μm or less and a Mohs hardness of 7 or less, and having a weight of 3.0 μm or more and 8.0 μm or less. The layer B contains inorganic particles and/or organic particles having a volume average particle diameter (dB) of 0.3 μm or more and 1.5 μm or less and a Mohs hardness of 7 or less, and contains 0.6% by mass or more based on the weight of the layer B. The inorganic particles having a Mohs hardness of 7 or less by weight or less include an organic particle having a weight of 0.05% by weight or more and 5% by weight or less based on the weight of the layer B, and a layer having a thickness of 10.0 μm or more and 35.0 μm or less; The weight relative to the C layer is 0.03% by weight or more and less than 1.0% by weight of a volume average particle diameter (dC) of 0.2 μm or more and 1.0 μm or less, one or two peaks of organic particles in a particle size distribution curve, and a layer having a thickness of 0.5 μm or more and 2.0 μm or less; Formula (1), and the thickness of the entire layer is 20 μm or more and 40 μm or less; dA < dC ≦ dB... Formula (1).

Description

Biaxially oriented polyester film for demolding

The present invention relates to a base film for mold release based on a biaxially stretched polyester film.

With the recent popularization of smart phones, the small-capacity and high-capacity of multilayer ceramic capacitors has also evolved. Therefore, for the release film used in the manufacture of the laminated ceramic capacitor, the demand for the smoothness of the polyester film having high smoothness and the surface of the film and the interior of the film is increased.

Regarding a highly smooth polyester film for mold release, it has been disclosed that a layer constituting a surface on which a ceramic slurry is formed is substantially free of particles, and a three-dimensional center plane roughness (SRa) of the surface thereof is 2 to 7 nm. This can reduce the base film produced by the pinholes on the green sheet (Patent Document 1). Further, there has been disclosed a technique for suppressing the coating property of a ceramic slurry by reducing the surface flaw of the green sheet formed by coating the ceramic slurry by reducing the pits on the surface of the film (Patent Document 2). Further, the high smoothing of the film causes a problem that "the film is charged, and the impurities adhering to the film are caught by the static electricity, and the ridges are generated". In response to this problem, a method of setting the winding step of a film to a specific condition has been disclosed (Patent Document 3). Further, in order to achieve high smoothness, reduction in impurities, and reduction in production cost, a method of not mixing fine particles in an intermediate layer of a different type of three-layer structure has been disclosed (Patent Document 4).

Recently, since multilayer ceramic capacitors require high precision, the release film used in the manufacture of laminated ceramic capacitors requires high build-up precision when the ceramic green sheets are laminated in a plurality of layers. Therefore, the release film used in the manufacture of the laminated ceramic capacitor is required to be rigid or cushioning as a support for the film. When the release film is insufficient in rigidity or cushioning property as a support for the film, in the green sheet cutting step, the cutting is not performed correctly, or the cut surface is unstable, causing the green sheet to be cleaved. Further, in the lamination step after the green sheet is cut, the uniform heating is not uniformly performed, and the layer cannot be uniformly laminated.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-62179

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-210226

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2004-196873

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2004-196856

It is an object of the present invention to provide a ceramic capacitor which is assembled when a multi-function mobile terminal other than a smart phone guide is manufactured, and which can adjust the coating property of the green slurry during forming of the green sheet, and the green sheet punching property. A biaxially oriented polyester film for demolding which is balanced with the properties of the green sheet.

The inventors of the present invention are committed to conducting research in view of the above-mentioned current situation. As a result, by adjusting the laminated structure of the film and limiting the type and amount of the added particles, a release polyester film suitable for film green sheet formation is found, and the present invention is completed.

That is, the present invention relates to the first invention and the second invention described below. Hereinafter, the present invention refers to the first invention and the second invention unless otherwise specified.

The first invention is a biaxially oriented polyester film for mold release, which comprises a three-layer polyethylene terephthalate film characterized by having a surface layer (layer A), an intermediate layer (layer B), and a surface layer (C). The layer A contains inorganic particles having a volume average particle diameter (dA) of 0.1 μm or more and 1.0 μm or less and a Mohs hardness of 7 or less with respect to the weight of the layer A of 0.05% by weight or more and 1.0% by weight or less. Or a layer having a thickness of 3.0 μm or more and 8.0 μm or less, and a layer having a thickness of 10.0 μm or more and 35.0 μm or less, and having a volume average particle diameter (dB) of 0.3 μm or more and 1.5 μm or less, Mohs. The inorganic particles and/or the organic particles having a hardness of 7 or less contain inorganic particles having a Mohs hardness of 7 or less and 6 or less by weight with respect to the weight of the layer B of 7 or less, and are 0.05 based on the weight of the layer B. The organic particles having a Mohs hardness of 7 wt% or less and 7 wt% or less; and the C layer containing 0.03 wt% or more and less than 1.0 wt% of the weight of the C layer have a volume average particle diameter (dC) of 0.2 μm or more and 1.0 or more. Organic particles having one or two peaks in the particle size distribution curve below μm and having a thickness of 0.5 μm The following layers 2.0μm; A layer, B layer, and C layer, the volume-based average particle diameter of particles contained in relation formula (1), the whole of the layer and the thickness of 20μm or less than 40μm; dA<dC≦dB... Equation (1).

The second invention is a biaxially oriented polyester film for demolding, which comprises a three-layer polyethylene terephthalate film characterized by having a surface layer (A' layer), an intermediate layer (B' layer), and a surface layer. (C' layer), wherein the center line roughness SRa (A') of the surface of the A' layer is 3 nm or more and 10 nm or less, and the center line roughness SRa (C') of the surface of the C' layer is 10 nm or more and 30 nm or less; The A' layer and the B' layer are layers containing particles, and the particles contained in the A' layer and the B' layer are inorganic particles and/or organic particles having a Mohs hardness of 7 or less, and/or a degree of crosslinking of 50~. 85% organic particles.

According to the present invention, the coating property of the ceramic slurry and the green sheet punching property at the time of forming the green sheet of the film can be improved.

[Formation of the Invention]

Hereinafter, the present invention will be described in further detail.

The "release molding" of the biaxially oriented polyester film for mold release according to the first aspect of the invention refers to a use of a polyester film substrate to mold a member and to peel off the molded member. The member may be a green sheet of a multilayer ceramic capacitor, an interlayer insulating resin (electric insulating resin) of a multilayer circuit board, or a polycarbonate of an optical related member (in this case, used for forming a solution).

The biaxially oriented polyester film for mold release according to the first aspect of the invention is particularly suitable for demolding in a multilayer ceramic capacitor, and the film green sheet is used. The coating property of the ceramic slurry at the time of molding, the green sheet punching property, and the green sheet laminate property were good.

The "biaxial alignment" of the biaxially oriented polyester film for mold release according to the first aspect of the invention is a figure showing a biaxial alignment in a wide-angle X-ray diffraction. Further, it means a state in which an unextended (unaligned) film is extended in a two-dimensional direction by a conventional method. The extension may be either a sequential biaxial extension or a simultaneous biaxial extension. In the case of the sequential biaxial stretching, the steps of extending in the longitudinal direction (longitudinal direction) and the width direction (horizontal direction) may be performed once in each of the vertical and horizontal directions, or may be performed in two steps of longitudinal-horizontal-vertical-horizontal.

The biaxially oriented polyester film for mold release according to the first aspect of the invention comprises three layers of a polyethylene terephthalate film, that is, a layer including a surface layer (layer A), an intermediate layer (layer B), and a surface layer (layer C). The laminated film (biaxially oriented polyester film for demolding). Poly(ethylene terephthalate) is excellent in physical properties such as mechanical strength or dimensional stability, and is excellent in productivity. When used as a release film used for the manufacture of a laminated ceramic capacitor, its economy and slit processing (slit processing) (slitting) is easy to carry out, and when the green sheet is die-cut, the rigidity required as a support can be imparted. The above polyethylene terephthalate can be produced by a known method, and the intrinsic viscosity is preferably 0.5 dl/g or more and 0.8 dl/g or less. More preferably, it is 0.55 dl / g or more and 0.70 or less. The polyethylene terephthalate constituting each layer may contain a copolymerization component as long as the properties are not impaired. As the aromatic dibasic acid, isomeric acid, citric acid, naphthalene dicarboxylic acid, diphenyl sulfonium dicarboxylic acid, diphenyl ether dicarboxylic acid, benzophenone dicarboxylic acid, benzene can be used as the aromatic dibasic acid. A decane dicarboxylic acid, a sodium isodecanoate sulfonate, a dibromo phthalic acid or the like. As the alicyclic dibasic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, sebacic acid, dimer acid or the like can be used. In the case of diols, as As the aliphatic diol, ethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol, etc. may be used; as the aromatic diol, naphthalenediol, 2, 2 may be used. - bis(4-hydroxydiphenyl)propane, 2,2-bis(4-hydroxyethoxyphenyl)propane, bis(4-hydroxyphenyl)anthracene, hydroquinone, etc.; as an alicyclic diol As the cyclohexanedimethanol, cyclohexanediol or the like.

The layer A is preferably a layer constituting the surface on which the ceramic slurry is applied after the release layer is provided; the layer C is suitable for the layer constituting the opposite surface of the release layer, and the layer B is a layer between the layer A and the layer C.

In this case, by controlling the types of particles and the amount of particles added to each of the layers of the A layer, the B layer, and the C layer, and appropriately forming the inner layer portion within a range that does not adversely affect the surface characteristics of the film, the film forming step is appropriately mixed. The cost of the recycled raw material in the edge portion produced in the middle portion or the recycled raw material in the other film forming step can be obtained.

Further, in order to adjust the protrusion height on the surface of the film layer or the center line roughness of the surface of the film layer, to suppress thermal deterioration during recovery of the raw material, and to improve the coating property of the ceramic slurry, green sheet punching property, and raw In the layered nature of the green sheet, "polyethylene terephthalate constituting the layer A contains inorganic particles and/or organic particles having a Mohs hardness of 7 or less, and the polyethylene terephthalate constituting the layer C is contained in the particle size. Organic particles having one or two peaks in the distribution curve are necessary for good green die cutting. Further, "the inorganic particles and/or organic particles having a Mohs hardness of 7 or less in the polyethylene terephthalate constituting the layer B" are also essential. The organic particles contained in the A layer, the B layer, and the C layer may be the same substance or different substances. Further, the inorganic particles contained in the A layer and the B layer having a Mohs hardness of 7 or less may be the same substance or different substances.

The type of the inorganic particles having a Mohs hardness of 7 or less is preferably spherical cerium oxide, aluminum silicate, titanium oxide or calcium carbonate. The organic polymer particles are preferably crosslinked polystyrene resin particles, crosslinked epoxy resin particles, crosslinked acrylic resin particles, crosslinked styrene-acrylic resin particles, crosslinked polyester particles, and polyimine. Particles, melamine resin particles, and the like. In order to impart moderate cushioning properties (also referred to as cushioning properties) to the biaxially oriented polyester film for release, it is preferred to use such particles.

The coating property of the ceramic slurry is a molded body obtained by applying a dielectric material of a ceramic capacitor to a release film containing a biaxially oriented polyester film for mold release, and then drying the molded body, that is, a ceramic sheet (so-called green body) The presence or absence of a pinhole, the surface state of the sheet and the surface state of the end.

Moreover, the green sheet punching property indicates whether or not the green sheet is cut in a desired shape without being damaged when the green sheet is formed by laminating the green sheet formed on the release film.

The green sheet layering property is a step of peeling off the release film after the green sheet which has been cut in the above step is subjected to heat-pressure bonding to the substrate, and the laminate can be laminated without impurities, and the green sheet is not damaged. The characteristics of the stripping of the sheet. The description of these assessment techniques is described below.

The thickness of the biaxially oriented polyester film for mold release according to the first aspect of the invention is 20 μm or more, preferably 25 μm or more, and more preferably 31 μm or more. The upper limit is 40 μm or less, preferably 38 μm or less. When the thickness is thinner than 20 μm, the rigidity for holding the ceramic slurry disappears, and in the coating of the ceramic slurry, the ceramic slurry cannot be supported, and it is not uniformly dried in the subsequent step. When the thickness exceeds 40 μm, it is easy to scratch in the conveyance step at the time of film production.

The thickness of the layer A of the first invention is 3.0 μm or more and 8.0 μm or less. When the thickness is less than 3.0 μm, the buffer properties at the time of punching of the green sheet which is exhibited by the appropriate particle type and particle amount are not sufficiently exhibited. On the other hand, when the thickness of the laminate exceeds 8.0 μm, it is not preferable that the particles are not formed by the particles.

The thickness of the layer B of the first invention is 10.0 μm or more and 35.0 μm or less. The B layer together with the A layer contributes to the cushioning property of the green sheet when punching, and at the same time, it also affects the layering property of the green sheet together with the layer C. When the layer B is less than 10.0 μm, the cushioning property is lowered, and when it is more than 35.0 μm, the layering property of the green sheet is lowered.

Further, the thickness of the C layer of the first invention is 0.5 μm or more and 2.0 μm or less. When the thickness is less than 0.5 μm, the particles contained in the layer C fall off. On the other hand, when the thickness exceeds 2.0 μm, the uniformity of the formation of the protrusions of the particles is impaired.

In the thickness of the layer B of the first invention, the thickness of the layer A and the thickness of the layer C are selected within the above range, and the thickness of the entire laminated film is selected within the above range. In the case of the layer B, it is preferable to add the recovered material containing the chips generated in the production step of the polyester film from the viewpoint of cost, and adjust the volume A with respect to the volume average particle diameter of the particles in the layer B. The balance of the particles added to the layer and the layer C is preferable in terms of both the green sheet punching property and the green sheet layering property.

Further, it is preferable that the recycled raw material which can be added to the layer B is only the biaxially stretched generated scrap generated in the polyester film production step of the first invention. However, since the shape or bulk density of the recovered raw material may cause the drying efficiency of the raw material to deteriorate, or the discharge in the extrusion step is unstable, The blending ratio of the raw material added to the layer B to the raw material of the layer B is adjusted according to the desired amount to suit the suitability of the drying or extruding step, and the haze described later is preferably controlled. value.

Further, in terms of recovering the raw material, it is more preferable to add only the scrap generated in the step after the intermediate product is rolled up. Further, in terms of recovering the raw material, it is preferred to homogenize the heat history before the recovered raw material is obtained. For example, when the unaligned film and the biaxially stretched film are mixed and recovered, the melt viscosity is unstable due to the difference in crystallinity, and the punchability of the green sheet is changed. Further, if a difference in melting point occurs at the time of remelting, and an unmelted impurity or a thermally deteriorated impurity is generated, the impurity forms a coarse protrusion. When the coarse protrusion is larger than the layer thickness of the A layer or the C layer, coarse protrusions are formed on the surface of the A layer or the C layer. At this time, in particular, when a surface protrusion is formed on the side of the layer A, pinholes of the green sheet are generated.

In the biaxially oriented polyester film for mold release according to the first aspect of the invention, the layer A contains 0.05 to 1.0% by weight of the weight of the layer A, and the volume average particle diameter is 0.1 μm or more and 1.0 μm, and the Mohs hardness is 7 or less. Particles and/or organic particles are essential. The B layer contains inorganic particles and/or organic particles having a volume average particle diameter of 0.3 μm or more and 1.5 μm or less and a Mohs hardness of 7 or less. When the particles contained in the layer B are inorganic particles having a Mohs hardness of 7 or less, they are contained in an amount of 0.6 to 6% by weight based on the weight of the layer B, and in the case of organic particles, 0.05 to 5% by weight based on the weight of the layer B. It is a necessary condition. Further, the C layer contains organic particles having a volume average particle diameter of 0.03 to 1.0% by weight based on the weight of the C layer of 0.2 μm or more and 1.0 μm, and one or two peaks in the particle size distribution curve.

Volume average particles of particles added to layers A, B, and C The relationship between the diameters dA, dB, and dC at dA < dC ≦ dB is a necessary condition. The biaxially oriented polyester film for mold release according to the first aspect of the invention is characterized in that the particle type or size of the three types of structures in different types is limited, and the particles themselves are elastically deformed and biaxially stretched. The number of voids (voids) generated around the particles is controlled within an appropriate range, and the coating properties of the ceramic slurry during the formation of the green sheet of the film, the green sheet punching property and the green sheet laminate characteristics can be obtained. Balance.

The green sheet punching properties and the green sheet layer properties are exhibited by the cushioning properties of the minute regions in the film. For the punching property of the green sheet, it is necessary to absorb the impact generated by the punching blade received from the A layer side in the A layer and the B layer. In the step of applying hot pressing in the green sheet layer, it is necessary to conduct heat uniformly to the C layer to the B layer, the B layer to the A layer. Further, in order to homogenize the pressure at the time of hot pressing, it is necessary to increase the cushioning property of the B layer of the thickest layer. The pore size is determined by the type, the amount of addition, and the particle diameter of the particles. In particular, when the pressure in the thickness direction is considered, the effect of the particle diameter is high.

In order to control the fine cushioning performance of the film, the particles contained in the A layer, the B layer, and the C layer used in the first invention are uniformly laminated by the heat-deposited layer of the ceramic green sheet, and then the release of the release film is selected. It is preferred to use organic particles having a high degree of particle elasticity. The organic particles are particularly preferably organic particles selected from the group consisting of crosslinked polystyrene resin particles, crosslinked epoxy resin particles, crosslinked acrylic resin particles, crosslinked styrene-acrylic resin particles, and crosslinked polyester particles. In order to use the inorganic particles in the same manner as the organic particles, a Mohs hardness of 7 or less is essential.

That is, the aforementioned inorganic particle type having a Mohs hardness of 7 or less Among them, inorganic particles having a Mohs hardness of 7 or less are particularly preferably spherical cerium oxide or aluminum silicate.

It is preferably a particle shape. The particle size distribution is uniform, and it is particularly preferable that the particle shape is approximately spherical. The volume shape factor is preferably f = 0.3 to π / 6, more preferably f = 0.4 to π / 6. The volume shape factor f is expressed by the following formula: f = V / Dm ³

Here, V is a particle volume (μm ³ ), and Dm is a maximum diameter (μm) on the projection surface of the particle.

Further, in the case of the volume shape factor f, if the particles are balls, the maximum π/6 (=0.52) is used. Further, it is preferred to perform filtration or the like as needed to remove aggregated particles or coarse particles. Among the organic particles, crosslinked polystyrene resin particles, crosslinked oxirane resin particles, and crosslinked acrylic resin particles synthesized by an emulsion polymerization method or the like can be suitably used, and particularly crosslinked polystyrene particles and crosslinked oxime resins are used. Even spherical yttrium oxide or the like is preferable in that the volume shape coefficient approximates the true sphere, the particle size distribution is extremely uniform, and the surface protrusion of the film is uniformly formed.

In the biaxially oriented polyester film for mold release according to the first aspect of the invention, one or two peaks are required in the particle size distribution curve of the particles contained in the layer C. When the biaxially oriented polyester film for mold release according to the first aspect of the invention is used for a support for green sheet forming in the step of producing a laminated ceramic capacitor, a release layer is formed on the surface of the layer A, and is maintained on the release layer. The green sheet is rolled up. After being rolled up, the surface of the layer C is crimped to the green sheet due to the effect of the winding. At this time, the surface shape generated by the protrusions on the surface of the layer C is transferred to the green sheet. The transfer marks at this time affect the morphology of the green sheet and affect the dielectric constant of the capacitor. To prevent such transfer marks from being attached to the green sheet, then for C The surface of the layer is required to uniformly disperse the pressure when crimped onto the surface of the green sheet. For this reason, the height of the protrusions formed on the flat surface of the surface of the C layer needs to be uniform.

Further, the protrusion on the surface of the layer C will hook the surface of the green sheet to wind the green sheet when the green sheet is wound up. Such hooking can be prevented by making the height of the protrusions formed on the flat surface of the surface of the C layer uniform.

Further, the protrusions on the surface of the C layer can also prevent agglomeration of the green sheets from the surface of the C layer. In the highly smooth release film which can form a green sheet of a film, the green sheet is easily brought into contact with a flat surface on the surface of the C layer where no protrusion is formed. When the peak of the particle size distribution of the particles contained in the layer C is one, the contact with the green sheet is most uniform, but the flat surface of the surface of the layer C is easily adhered to the green sheet. Further, the adhesion between the surface of the layer C and the green sheet is too uniform, and an excessive peeling force is required at the initial stage of peeling. At this time, when a portion having a weak microscopic peeling force is formed, the portion becomes a starting point of peeling, and peeling is easily performed at the initial stage of peeling. The present inventors have found that in order to form the surface of the layer C to be easily peeled off at the initial stage of peeling, it is possible to form the particles contained in the layer C by particles having two peaks in the particle size distribution curve. However, when the particles contained in the layer C have more than three peaks in the particle size distribution curve, the height difference between the protrusions is uneven, and the dispersion of the pressure is too disordered to cause excessive pressure on a certain portion.

Further, by subjecting the particles to a surface treatment using a surfactant or the like, it is preferable to improve the affinity with the polyester and to form a projection having less peeling.

In the biaxially oriented polyester film for mold release according to the first aspect of the invention, the center line roughness SRa (A) of the surface of the layer A is preferably 3 nm or more and 10 nm or less, C The center line roughness SRa (C) of the layer surface is preferably 10 nm or more and 30 nm or less. Further, the ten-point average roughness SRz (A) of the surface of the layer A is preferably 300 nm or less, and the ten-point average roughness SRz (C) of the surface of the layer C is preferably 600 nm or less, so that the green sheet having a thickness of 2 μm or less is formed. It is preferable to obtain appropriate smoothness. When the center line roughness SRa (A) of the surface of the layer A is set within the above range, it is possible to improve the occurrence of agglomeration during the storage of the film roll after the release of the release layer or uneven coating of the ceramic slurry. The green sheet generates a problem such as pinholes. Further, by setting the ten-point average roughness SRz (A) of the surface of the layer A to the above range, the surface morphology of the green sheet on the surface in contact with the layer A can be improved, and the variation in the electrostatic capacitance of the ceramic capacitor can be suppressed. Further, when the surface of the layer C is processed in the biaxially oriented polyester film for mold release according to the first aspect of the invention, it is required to be the opposite side of the machined surface in the release layer coating step or the ceramic slurry coating step. Handling. In addition, the green sheet obtained by applying the slurry and drying is held on the release film obtained by applying the release layer to the biaxially oriented polyester film for mold release of the first invention, and is wound up. As mentioned above, the shape of the surface of the C layer affects the surface morphology of the green sheet after winding. In other words, by setting the center line roughness SRa (C) of the surface of the C layer to a range of 10 nm or more, the rationality of the release layer coating step or the slurry coating step can be improved, and uneven coating or curling after coating can be suppressed. The air that is jammed is not easily separated from the resulting curl. Further, by setting the center line roughness SRa (C) of the surface of the layer C to 30 nm or less, the influence of the unevenness formed on the surface on the surface of the green sheet can be reduced, and the variation in the electrostatic capacity of the ceramic capacitor can be suppressed. Further, by setting the ten-point average roughness SRz (C) of the surface of the C layer to 600 nm or less, it is possible to suppress the occurrence of pits or pinholes on the surface of the rolled green sheet. The generation of the breakdown voltage of the ceramic capacitor is suppressed. These can be achieved by including a specific amount of specific organic particles and/or inorganic particles in the layer A, and the layer C contains a specific amount of specific organic particles. The sum of the fracture strength in the longitudinal direction and the transverse direction of the biaxially oriented polyester film for mold release according to the first aspect of the invention is preferably 500 MPa or more and 600 MPa or less, more preferably 520 MPa or more and 590 MPa or less. Further, the breaking strength in the width direction is preferably equal to or higher than the breaking strength in the longitudinal direction, and the difference (the breaking strength in the width direction - the breaking strength in the longitudinal direction) is preferably 0 MPa or more and 90 MPa or less, more preferably 40 MPa or more and 80 MPa or less. . When the sum of the fracture strengths in the longitudinal direction and the transverse direction is 500 MPa or more, it is easy to exhibit a pore (void) structure in which the polymer around the particles is peeled off from the particles in the stretching step, and the center line of the surfaces of the A layer and the C layer can be roughened. The degree is controlled to a desired value, and the cushioning property is exhibited well. Further, in order to achieve a state in which the sum of the breaking strengths in the longitudinal direction and the transverse direction is higher than 600 MPa, it is necessary to perform excessive stretching in the longitudinal direction or the width direction, so that cracking is not preferable in the stretching.

Further, the elongation in the longitudinal direction and the transverse direction is preferably 80% or more and 220% or less, more preferably 90% or more and 210% or less. Further, the rupture elongation in the longitudinal direction is preferably equal to or higher than the rupture elongation in the width direction, and the difference (the rupture elongation in the longitudinal direction - the rupture elongation in the width direction) is 0% or more and 100% or less. good. In addition, the elongation at break in the longitudinal direction is 170% or more and 190% or less, the elongation at the width direction is 90% or more and 110% or less, and the rupture elongation in the longitudinal direction is 70% or more and 90% larger than the rupture in the width direction. The following is better. The rupture elongation in the longitudinal direction and the transverse direction is set to 80% or more, and when the ceramic slurry is applied, the tension in the step is absorbed, and the tension variation is absorbed, and uneven coating is suppressed. It is better to produce. Further, the rupture elongation in the longitudinal direction or the transverse direction is set to 220% or less, and when the release layer is applied and stored, it is possible to suppress the deterioration of the planarity. Further, when the ceramic slurry is applied and stored, it is possible to suppress the deterioration of the planarity of the green sheet. By controlling the rupture elongation within the above range, it is possible to control the phenomenon of stretching and contraction of the film due to the tension experienced in the processing step, or the behavior of residual stress recovery after winding, and finally the green sheet of the film can be well preserved. Flatness. Further, the reason why the rupture elongation in the longitudinal direction is preferably equal to or higher than the rupture elongation in the width direction is as follows: in the step of applying the release layer and the winding step, tension is applied in the longitudinal direction of the film; After being rolled up, it remains as a film internal stress. Thereafter, when tension is applied in the longitudinal direction, the film in the width direction is changed in size due to the deformation of Paisson. The dimensional change in the width direction causes planarity defects when the film roll coated with the release layer is wound up. In order to suppress the dimensional change, it is preferable that the elongation in the longitudinal direction is equal to or higher than the fracture elongation in the width direction, and the difference in the elongation in the longitudinal direction and the width direction is within the above range.

Further, the biaxially oriented polyester film for mold release according to the first aspect of the invention preferably has a haze of 7% or less, more preferably 6% or less. As a mold release application of the laminated ceramic capacitor, the recovered raw material can be added to the intermediate layer of the three-layer composite layer. However, when the haze exceeds 7%, the state of the green sheet is not easily confirmed, and the state of the end portion is particularly poor.

Furthermore, the thickness unevenness in the longitudinal direction of the polyester film of the first invention is preferably 2 μm or less. Further, in the present invention, the thickness unevenness in the longitudinal direction is measured by the thickness of the film of 15 m along the length direction of the film, and the thickness of the film is recorded, and the maximum thickness and the minimum thickness of the film are The difference is sought. It is preferably 1.4 μm or less. In order to reduce the thickness unevenness of the film, it is a problem in the production of a film. However, in order to apply the film for mold release of the first invention, in particular, a release film suitable for the production of a film ceramic capacitor, the thickness unevenness in the longitudinal direction is made. Within the above range, it is preferred that the electrostatic capacity of the capacitor does not change when the thickness of the green sheet is reduced.

In the polyester film of the first aspect of the invention, the coarse protrusions having a height of 0.27 μm or more on the surface of the film are preferably 5 pieces/100 cm ² or less. Further, the coarse protrusions of 0.54 μm or more are preferably one/100 cm ² or less. More preferably, the coarse protrusions of 0.54 μm or more are substantially absent. When the number of the coarse protrusions is set within the above range, when the release agent is applied, coating unevenness and pinhole-like coating peeling can be suppressed. Further, it is possible to suppress the occurrence of peeling unevenness of the green sheet due to the application of the release agent peeling off when the thickness of the green sheet is reduced. Further, it is possible to suppress the occurrence of pits or pinholes in the green sheets due to the coarse protrusions.

In order to achieve the above-described preferred embodiment of the coarse protrusions on the surface of the film, the particle type and the volume average particle diameter contained in the A layer, the B layer, and the C layer are in the above range. In addition, the apparatus for supplying the raw material of the polyester film of the first invention, in particular, the raw material storage device (silo) and the piping for the transportation of the raw material are used only for the particles used in the first invention. The master pellet is used to transport the raw materials and the like as follows. In order to transport raw materials, they are transported by air using a blower or by free fall, but when transported by air, it is preferable to use 95% of the dust when filtering air. A filter of dust above μm filters the air. In addition, the filter used in the manufacture of the first invention can be achieved by using a high-precision filter to be described later.

In the polyester film of the first aspect of the invention, the dimensional change rate is appropriately controlled, and the post-processing is favorably maintained, and in particular, the planarity after the release of the release layer is preferable. The method of setting the dimensional change rate within the range described later can be achieved by appropriately adjusting a known method such as relaxation treatment in the film formation conditions. The dimensional change rate at 150 ° C is preferably 2% or less in the longitudinal direction, 2.5% or less in the width direction, more preferably 0.5% or more and 1.7% or less in the longitudinal direction, and 1% or more and 2% or less in the width direction. Further, the dimensional change ratio at 100 ° C is preferably 1% or less in the longitudinal direction and the width direction, and more preferably in the range of 0.2% or more and 0.8% or less. When the dimensional change rate is lower than the lower limit of the above range, the planarity defect due to relaxation occurs when the release layer is applied; when the release layer is applied, the shrinkage unevenness due to shrinkage occurs when the release layer is applied, resulting in a flat surface. In some cases, the coating thickness unevenness of the film green sheets is not good.

Next, a method of producing the biaxially oriented polyester film of the first invention will be described. As a method of containing the inert particles in the polyester, for example, the inert particles are dispersed in a predetermined ratio in the form of a slurry in ethylene glycol as a diol component, and the ethylene glycol is added at any stage before the polymerization of the polyester is completed. Slurry. When the particles are added, for example, when the hydrosol or the alcohol sol obtained in the case of the synthetic particles is not temporarily dried, the dispersibility of the particles is good, and generation of coarse protrusions can be suppressed. Further, the method of mixing the water slurry of the particles directly with a predetermined polyester pellet and supplying it to a vented biaxial kneading extruder for incorporation into the polyester is also a manufacturing method of the first invention. effective.

Thus, the pellets prepared for the respective layers and substantially free of the main pellets and particles containing the particles are mixed in a predetermined ratio and dried. It is supplied to a known extruder for molten laminate. The extruder for producing a biaxially oriented polyester film for mold release according to the first aspect of the invention may be a single-shaft or two-axis extruder. Further, in order to omit the drying step of the pellets, a vented extruder equipped with an evacuation line in the extruder may be employed. Further, for the B layer having the largest amount of extrusion, a so-called tandem extruder which functions to melt the pellets and maintain the function of the molten pellets at a constant temperature by the respective extruders can be used. In the A-layer and the C-layer of the biaxially oriented polyester film for mold release according to the first aspect of the invention, it is preferred to use a biaxial aeration extruder because the dispersibility of the particles can be favorably maintained.

The melted, extruded polymer in the extruder is filtered using a filter. When extremely small impurities are also mixed into the film, coarse protrusions are caused. Therefore, it is effective to use a high-precision filter which can capture, for example, 95% or more of impurities of 3 μm or more. Subsequently, it was extruded into a sheet shape from a slit-shaped slit die, and cooled and solidified on a casting roll to form an unstretched film. That is, three extruders, three layers of manifolds or confluence blocks (for example, confluence blocks having rectangular confluences) are laminated into three layers, and then the sheets are extruded from the nozzles and cooled by the casting rolls to form Extend the film. At this time, it is effective to provide a static mixer and a gear pump in the polymer flow path from the viewpoint of stabilizing the back pressure and suppressing the thickness variation.

The extension method can be simultaneous biaxial extension or sequential biaxial extension. In particular, in the simultaneous biaxial stretching, the extension by the use of the roller is not accompanied, so that local uneven heating of the surface of the film can be suppressed, uniform quality can be obtained, and the film and the roll which are generated by the extension of the roller during stretching can be suppressed. It is preferable that the speed difference at the contact portion, the transfer of minute scratches of the roller, and the like are generated.

In the simultaneous biaxial stretching, the unstretched film is first extended in the length and width directions by an extension temperature of 80 ° C or more and 130 ° C or less, preferably 85 ° C or more and 110 ° C or less. When the stretching temperature is lower than 80 ° C, the film is easily broken, and when the stretching temperature is higher than 130 ° C, sufficient strength cannot be obtained. Furthermore, based on the idea of preventing uneven extension, the length direction. The total stretching ratio in the width direction is 4 times or more and 20 times or less, preferably 6 times or more and 15 times or less. When the total stretching ratio is less than 4 times, it is difficult to obtain sufficient strength. On the other hand, when the magnification is more than 20 times, the film is liable to be broken and it is not easy to manufacture a stable film. In order to obtain the required strength, the temperature is preferably 140 ° C or more and 200 ° C or less, preferably 160 ° C or more and 190 ° C or less in the longitudinal direction and/or the width direction by 1.02 times or more and 1.5 times or less, preferably 1.05 times or more. When the magnification is less than the fold, the total stretch ratio is 3 times or more and 4.5 times or less in the longitudinal direction, preferably 3.5 times or more and 4.2 times or less, and 3.2 times or more and 5 times or less in the width direction, preferably 3.6 times or more and 4.3 times or less. . In order to achieve the target film breaking strength, the magnification can be appropriately selected, and in order to increase the breaking strength in the width direction, it is preferable to set the stretching ratio in the width direction to be slightly higher than the length direction. Thereafter, it is thermally fixed at 205 ° C or higher and 240 ° C or lower, preferably 220 ° C or higher and 240 ° C or lower for 0.5 second or longer and 20 seconds or shorter, preferably 1 second or longer and 15 seconds or shorter. When the heat setting temperature is lower than 205 ° C, the thermal crystallization of the film does not proceed, so that the dimensional change rate of the target is difficult to achieve stability. Further, in order to stabilize the physical properties of the film, the temperature difference between the upper and lower sides of the film is 20 ° C or lower, preferably 10 ° C or lower, more preferably 5 ° C or lower. When the temperature difference between the upper and lower sides of the film is more than 20 ° C, it is liable to cause a slight deterioration in planarity during heat treatment. Thereafter, a relaxation of 0.5% or more and 7.0% or less is performed in the length and/or width direction. Reason.

At the same time, the biaxial stretching is different from the successive biaxial stretching described later, and the film is heated by high temperature air. Therefore, it is not only that the surface of the film is locally heated to cause adhesion, and it is more preferable to extend it as a stretching method.

On the other hand, the polyester film of the first invention can also be produced by sequential stretching. The extension of the first longitudinal direction is extremely important for suppressing the generation of scratches, and the elongation temperature is 90 ° C or more and 130 ° C or less, preferably 100 ° C or more and 120 ° C or less. When the elongation temperature is lower than 90 ° C, the film is easily broken. When the extension temperature is higher than 130 ° C, the surface of the film is susceptible to thermal damage. Further, based on the viewpoint of preventing the unevenness of the extension and the kiss, the extension is preferably carried out in two or more stages, and the total magnification is three times or more and 4.5 times or less, preferably 3.5 times or more and 4.2 times in the longitudinal direction. Hereinafter, it is 3.2 times or more and 5 times or less in the width direction, and preferably 3.6 times or more and 4.3 times or less. In order to achieve the target film breaking strength, the magnification can be appropriately selected, and in order to increase the breaking strength in the width direction, it is preferable to set the stretching ratio in the width direction to be slightly higher than the length direction. If the temperature and the range of the magnification are exceeded, problems such as uneven stretching or film breakage may occur, and it may be difficult to obtain a film which is characterized by the first invention. After the vertical or horizontal stretching is performed again, the heat is fixed at 205 ° C or higher and 240 ° C or lower, preferably 210 ° C or higher and 230 ° C or lower, and 0.5 seconds or longer and 20 seconds or shorter, preferably 1 second or longer and 15 seconds or shorter. In particular, when the heat setting temperature is lower than 205 ° C, the crystallization of the film does not proceed so that the structure is unstable, and the characteristics such as the dimensional change rate of the target cannot be obtained.

In the successive stretching, the length direction extending process is preferably for the film to be in contact with the roll, which is easy due to the difference between the peripheral speed of the roll and the speed of the film. In the step of generating scratches, the driving method of the peripheral speed of the rolls can be individually set for each roller. During the extension of the length direction, the material of the transport roller is transported to the extension zone in accordance with the state in which the unstretched film is heated above the glass transition point before stretching or at a temperature less than the glass transition point and is extended. It is selected by heating, and when the unstretched film is heated to a temperature above the glass transition point before stretching, it can be selected from non-adhesive silicone resin rolls, ceramics, TEFLON (registered trademark) in terms of preventing adhesion by heating. Further, in the case of the stretching roller, the step of applying the most load to the film and causing scratches or unevenness in the process, the center line roughness Ra of the surface of the stretching roll is 0.005 μm or more and 1.0 μm or less. It is preferably 0.1 μm or more and 0.6 μm or less. When Ra is larger than 1.0 μm, the unevenness of the surface of the roll may be transferred to the surface of the film when it is extended; on the other hand, when it is less than 0.005 μm, the roll adheres to the surface layer of the film, and the film is liable to be damaged by heat. In order to control the center line roughness of the surface of the stretching roller, it is effective to appropriately adjust the particle size of the abrasive, the number of grinding, and the like. The transport roller of the preheating zone is preferably surface treated with hard chrome or tungsten carbide when transported to the extension zone while maintaining the unstretched film at a temperature less than the glass transition point. The metal roll having a center line roughness Ra of the surface of the stretching roll of 0.2 μm or more and 0.6 μm or less.

In the biaxially oriented polyester film for mold release according to the first aspect of the invention, the uniaxially stretched film extending in the longitudinal direction is heated to 80° C. or more and less than 120° C. by a transverse stretcher, and is 3 times or more and less than 6 times. The film is extended in the width direction to form a biaxially oriented (biaxial alignment) film.

The biaxially oriented polyester film for mold release according to the first aspect of the invention can be further extended in each direction by one or more times, or simultaneously on both axes. Extend again. Further, the heat treatment of the film is carried out after the biaxial stretching, but the heat treatment may be carried out by any conventionally known method such as in an oven or a heating roll. The heat treatment temperature can be generally set to any temperature of from 150 ° C to less than 245 ° C, and the heat treatment time is preferably from 1 second to 60 seconds. The heat treatment can also be carried out by allowing the film to relax in the longitudinal direction and/or the width direction. Further, after the heat treatment, the temperature is lowered by 0% or more and 10% or less in the width direction at a temperature lower than the heat treatment temperature by 0 ° C to 150 ° C.

The heat-treated film can be adjusted in dimensional change rate or planarity, for example, by providing an intermediate cooling zone or a cooling zone. Further, in particular, in order to impart a specific heat shrinkability, it may be relaxed in the longitudinal direction and/or the transverse direction during the heat treatment or the intermediate cooling zone or the decooling zone thereafter.

The biaxially stretched film is cooled in the transporting step, and then the edge is cut off and then rolled up to obtain an intermediate product. In this transport step, the thickness of the film is measured, the data is fed back, the data is used, and the thickness of the film is adjusted by adjustment of the thickness of the mold or the like, and the impurity is detected by a helium detector.

In the case of cutting the edge, it is necessary to suppress the generation of chips for the biaxially oriented polyester film for demolding of the first invention. The cutting of the edge is performed by using a rounded edge, a shear edge, and a straight edge. When a straight edge is used, the portion where the blade contacts the film is not always the same portion, and the blade portion is suppressed from being worn. . Therefore, it is preferable to have an oscillation mechanism. Further, it is preferable to provide a suction means at the film cutting portion for sucking the generated chips or the chips generated by cutting the ends of the cut film from each other.

The intermediate product is cut to the appropriate width by the cutting step. The roll of the biaxially oriented polyester film for mold release of the first invention is obtained by winding up the length. At the time of cutting the film in the cutting step, it may be selected from the same cutting method as the cutting of the aforementioned edge.

The intermediate product was cut into a desired width to obtain a biaxially oriented polyester film for mold release according to the first invention.

Next, the second invention will be described.

The "release molding" of the biaxially oriented polyester film for mold release according to the second aspect of the invention refers to a use of a polyester film substrate to mold a member and to peel off the molded member. The member may be a green sheet of a multilayer ceramic capacitor, an interlayer insulating resin (electric insulating resin) of a multilayer circuit board, or a polycarbonate of an optical related member (in this case, used for forming a solution).

In the biaxially oriented polyester film for mold release according to the second aspect of the invention, it is particularly suitable for demolding in a multilayer ceramic capacitor, and the coating property of the ceramic slurry at the time of forming the green sheet of the film, and green sheet punching The properties of the green and green sheets are good.

The "biaxial alignment" of the biaxially oriented polyester film for mold release according to the second aspect of the invention refers to a pattern showing biaxial alignment in wide-angle X-ray diffraction. Further, it means a state in which an unextended (unaligned) film is extended in a two-dimensional direction by a conventional method. The extension may be either a sequential biaxial extension or a simultaneous biaxial extension. In the case of the sequential biaxial stretching, the steps of extending in the longitudinal direction (longitudinal direction) and the width direction (horizontal direction) may be performed once in each of the vertical and horizontal directions, or may be performed in two steps of longitudinal-horizontal-vertical-horizontal.

The biaxially oriented polyester film for mold release according to the second aspect of the invention comprises a three-layer polyethylene terephthalate film, that is, a surface layer (layer A) and an intermediate layer (B). Layer), surface layer (C layer) The three-layer laminated film (biaxial alignment polyester film for mold release). Poly(ethylene terephthalate) is excellent in physical properties such as mechanical strength and dimensional stability, and is excellent in productivity. When used as a release film used for the manufacture of a laminated ceramic capacitor, the economy and the cutting process are easy to carry out. The degree of rigidity required for the support can be imparted when the green sheet is die cut. The above polyethylene terephthalate can be produced by a known method, and the intrinsic viscosity is preferably 0.5 dl/g or more and 0.8 dl/g or less. In the production of the green sheet, after the laminated layer release layer or the green sheet as the substrate, the green sheet of the target is pressed by the punching edge, and the green sheet is easily removed from the substrate layer. In the step of peeling, if the intrinsic viscosity is set in the vapor range, the hardness of the finally obtained polyester film can be in an appropriate range, the warpage of the film can be suppressed, and the flatness and the punching property of the green sheet can be improved. . Further, when the film is punched, the generation of chips (broken powder of the film) can be suppressed, and the punching property and the layering property of the green sheet can be improved. More preferably, it is 0.55 dl / g or more and 0.70 or less. The polyethylene terephthalate constituting each layer may contain a copolymerization component as long as the properties are not impaired. As the aromatic dibasic acid, isomeric acid, citric acid, naphthalene dicarboxylic acid, diphenyl sulfonium dicarboxylic acid, diphenyl ether dicarboxylic acid, benzophenone dicarboxylic acid, benzene can be used as the aromatic dibasic acid. A decane dicarboxylic acid, a sodium isodecanoate sulfonate, a dibromo phthalic acid or the like. As the alicyclic dibasic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, sebacic acid, dimer acid or the like can be used. In the case of the diol, as the aliphatic diol, ethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol, or the like can be used; as the aromatic diol, an aromatic diol can be used. Naphthalenediol, 2,2-bis(4-hydroxydiphenyl)propane, 2,2-bis(4-hydroxyethoxyphenyl)propane, bis(4-hydroxyphenyl)anthracene, hydroquinone, etc. As an alicyclic diol, it can be used as a cyclohexane Dimethanol, cyclohexanediol, etc.

The biaxially oriented polyester film for mold release according to the second aspect of the invention is a laminated film (double-axis alignment polyester film for mold release) comprising three layers of a polyester A' layer, a polyester B' layer and a polyester C' layer. It is a necessary condition.

The A' layer is suitable for forming a layer coated with a ceramic slurry surface after the release layer is provided on the surface of the A' layer; the C' layer is suitable for the layer forming the opposite side of the A' layer, and the B' layer is located at the A layer. The layer between the 'layer and C' layer.

The center line roughness SRa (A') of the surface of the A' layer is required to be 3 nm or more and 10 nm or less. In the case of the A' layer, if the planarity of the green sheet is considered, the center line roughness SR (A') of the surface of the layer A is required to be low. When the center line roughness SRa (A') of the surface of the layer A is less than 3 nm, in the manufacturing step of the biaxially oriented polyester film for demolding, the surface of the film may be scratched by the rubbing step of the manufacturing step, which may hinder the production. The surface properties of the green sheet deteriorate the coatability. Further, in the storage of the film roll after the release layer coating, agglomeration occurred in the A' layer and the release layer. In addition, when it exceeds 10 nm, the coating of the mold release material and the ceramic slurry is not uniform, and when the green sheet is peeled off, it is easy to form pinholes or the like on the surface of the green sheet, which affects the layer properties of the green sheet.

The center line roughness SRa (C') of the surface of the C' layer is required to be 10 nm or more and 30 nm or less. The C' layer is a layer which is in contact with a roll to impart travelability in the step of applying a release material to the A' layer or the step of applying a ceramic slurry. When the center line roughness SRa (C') of the surface of the C' layer is less than 10 nm, the handleability is deteriorated, the coating of the A' layer is unstable, and coating unevenness of the release material or the ceramic slurry occurs. Moreover, when the film is rolled up after coating, the trapped air is not easily detached, so that the curling occurs, and the plane of the green sheet is hindered. Sex. Even if the release material or the ceramic slurry is uniformly applied, there is a tendency that the trapped air hinders the planarity of the green sheet. On the other hand, the C' layer is a layer which is in contact with the surface of the green sheet when the release material or the ceramic slurry is applied and then rolled up. Therefore, when the center line roughness SRa (C') of the surface of the C' layer exceeds 30 nm, the influence of the unevenness formed on the surface on the surface of the green sheet becomes large, and pits are generated in the green sheet. The flatness of the green sheet or the pits of the green sheet results in a change in the electrostatic capacity of the ceramic capacitor after the green sheet is laminated. The centerline roughness of the surface of the C' layer can be easily achieved by adding particles.

Any of the A' layer and the B' layer is a layer containing particles, and the particles are inorganic particles and/or organic particles having a Mohs hardness of 7 or less and/or organic particles having a degree of crosslinking of 50 to 85%. Necessary conditions. In the second aspect of the invention, the coating property, the punching property, and the green sheet layering property described below are used. However, it is necessary to add particles to the A' layer to form a coating property, and to add particles to the B' layer. It is necessary for the punching system. Further, the particles contained in the layers are inorganic particles having a Mohs hardness of 7 or less and/or organic particles or organic particles having a degree of crosslinking of 50 to 85%, so that the punching which can be achieved only by containing the particles can be improved. Properties and green sheet properties.

The process for producing a green sheet laminate in the process of producing a laminated ceramic capacitor is as follows: a laminate in which a green sheet is formed on a release film is placed on an adsorption stage and fixed. Next, the green sheet was cut into a predetermined size with a blade (at this time, the release film was not cut). Next, the laminate in which the green sheet was formed on the release film was transferred to another green sheet and laminated in this order. When laminating, it is necessary to heat and press the surface of the release film which is not laminated with the green sheet.

In the foregoing step, when the cut is made with the blade, the cut edge reaches the release film after the green sheet is cut. In this case, if the particles contained in the A' layer are particles having a Mohs hardness of 7 or less or a degree of crosslinking of 50 to 85%, warpage of the cut portion of the green sheet is less likely to occur (hereinafter referred to simply as "anti-warping" In the A' layer, the chips generated by the film cut-in are obtained, and as a result, the punching property and the green sheet characteristics are excellent. Furthermore, when the green sheet is laminated, the film itself is also pressurized; therefore, the particles of the A' layer are inorganic particles and/or organic particles having a Mohs hardness of 7 or less or a degree of crosslinking of 50 to 85. With % of organic particles, the particles themselves are flat in the film, thereby reducing the effect of transfer onto the surface of the green sheet. As a result, the planarity of the green sheet can be improved, and the layering characteristics of the green sheet can be improved.

In the B' layer, if the inorganic particles and/or organic particles having a Mohs hardness of 7 or less or the organic particles having a degree of crosslinking of 50 to 85% are used, the green layer is laminated as in the case of the A' layer. When the pressure is applied, since the particles are flat, the influence on the A' layer and the green sheet can be reduced, and the planarity of the green sheet can be improved. Further, since the formation of voids (voids) can be suppressed, heat conduction can be effectively performed, and the laminated property of the green sheets can be improved.

The particles contained in the A' layer, the B' layer, and the C' layer may be the same type or different types of materials.

As the type of the inorganic particles having a Mohs hardness of 7 or less, spherical cerium oxide, aluminum silicate, titanium oxide, or calcium carbonate is preferable. The organic particles having a Mohs hardness of 7 or less are preferably crosslinked polystyrene resin particles, crosslinked epoxy resin particles, crosslinked acrylic resin particles, crosslinked styrene-acrylic resin particles, crosslinked polyester particles, Polyimide particles, melamine resin particles, and the like.

It is preferably a particle shape. The particle size distribution is uniform, and it is particularly preferable that the particle shape is approximately spherical. The volume shape factor is preferably f = 0.3 to π / 6, more preferably f = 0.4 to π / 6. The volume shape factor f is expressed by the following formula: f = V / Dm ³

Here, V is a particle volume (μm ³ ), and Dm is a maximum diameter (μm) on the projection surface of the particle.

Further, in the case of the volume shape factor f, if the particles are balls, the maximum π/6 (=0.52) is used. Further, it is preferred to perform filtration or the like as needed to remove aggregated particles or coarse particles. Among them, crosslinked polystyrene resin particles, crosslinked oxirane resin particles, and crosslinked acrylic resin particles synthesized by an emulsion polymerization method or the like can be suitably used, and particularly crosslinked polystyrene particles, crosslinked oxirane resins, and even balls It is preferable that the yttrium oxide or the like is based on the volume shape coefficient to approximate the true sphere, the particle size distribution is extremely uniform, and the surface protrusion of the film is uniformly formed.

Further, the "degree of crosslinking" referred to herein is defined by the degree of crosslinking (%) = (weight of the crosslinking component in the raw material monomer) / total weight of the raw material monomer × 100.

In the present invention, the coating property of the ceramic slurry during the formation of the green sheet is applied to the release film of the biaxially oriented polyester film for demolding of the second invention by applying the dielectric of the ceramic capacitor. Further, the molded body obtained by drying, that is, the presence or absence of pinholes of the ceramic sheet (so-called green sheet), and the surface state of the sheet surface and the end portion were evaluated.

The green sheet punching property is evaluated whether the green sheet is kept in a target shape without damage when cutting the green sheet formed on the release film. Cut it.

The green sheet layering property is evaluated in the step of peeling off the release film after the green sheet which has been cut in the above step is bonded to the laminate of the green sheet by hot pressing, and the layer may be laminated without impurities. The green sheet was peeled off without damaging the green sheet. The description of these assessment techniques is described below.

The thickness of the entire biaxially oriented polyester film for mold release according to the second aspect of the invention is preferably 20 to 40 μm. The lower limit is preferably 25 μm, more preferably 31 μm. The upper limit is preferably 38 μm, more preferably 36 μm. By setting the thickness of the entire film to the above range, the film can be imparted with rigidity required for holding the ceramic slurry, and in the coating of the ceramic slurry, it can be uniformly dried in the subsequent step to improve the coating property. Further, the thermal conductivity can be made to be in an appropriate range, so that the laminate property can be improved when the green sheet is laminated.

The thickness of the A' layer of the present invention is preferably 3.0 μm or more and 8.0 μm or less. By setting the thickness of the A' layer to the above range, the cushioning property of the green sheet during punching can be improved, and the green sheet can be prevented from being caught on the side of the release film or warped at the end of the green sheet (hereinafter referred to as "reverse" The situation of "warping"). Further, it is possible to suppress the detachment of the particles, suppress the occurrence of particle sticking when the green sheets are laminated, and improve the layering properties of the green sheets. Further, the protrusion of the surface can be uniformly formed. In the manufacturing step of the release film, the surface of the A' layer can be suppressed from being generated by the rubbing of the surface of the manufacturing step, and the smoothness of the surface of the green sheet can be improved. Applicability. It is preferably 4.0 μm or more and 7.0 μm or less.

The thickness of the B' layer is preferably from 10.0 μm to 35.0 μm. Together with the A' layer, the B' layer contributes to the cushioning properties of the green sheet when it is die-cut, and at the same time it also affects the layering characteristics of the green sheet together with the C' layer. B' layer The thickness is in the above range, and the cushioning property is good, and the green sheet can be prevented from being caught on the A layer side, the warpage of the green sheet can be suppressed, and the punching property can be improved. Further, since the thickness of the B' layer is in the above range, moderate thermal conductivity can be obtained. Therefore, in the step of laminating the green sheets, the green sheets are peeled off from the release film and adhered to the laminate of the other green sheets.

The thickness of the C' layer is preferably 0.5 μm or more and 2.0 μm or less. When the thickness of the C' layer is set to the above range, similarly to the A' layer, the fall of the particles contained in the C' layer can be suppressed, and the occurrence of particle sticking in the green sheet laminate can be suppressed, and the layering property of the green sheet can be improved. Further, the protrusions on the surface can be formed uniformly, and the handleability at the time of film formation and the handleability at the time of lamination of the green sheet of the release film can be improved. Further, when the thickness of the C' layer is in the above range, when the particle size distribution curve of the particles contained in the C' layer to be described later is within a specific range, the protrusions formed by the particles can be made more uniform and preferable.

The thickness of the B' layer of the present invention is selected within the above range depending on the thickness of the A' layer and the thickness of the C' layer, and can be determined by selecting the thickness of the entire laminated film within the above range.

In the biaxially oriented polyester film for mold release according to the second aspect of the invention, the ten-point average roughness SRz (A') of the surface of the A' layer is preferably 300 nm or less, and the ten-point average roughness SRz of the surface of the C' layer (C) ') is 600 nm or less, and it is preferable to obtain appropriate smoothness in terms of, for example, a green sheet having a molded thickness of 2 μm or less.

By setting the ten-point average roughness SRz (A') of the surface of the A' layer to the above range, the surface morphology of the green sheet of the surface in contact with the layer A can be improved, and the variation in the electrostatic capacitance of the ceramic capacitor can be suppressed.

When the biaxially oriented polyester film for mold release of the second invention is processed on the surface of the C' layer, the surface of the C' layer is applied to the opposite side of the machined surface in the release layer application step or the ceramic slurry application step, and handleability is required. In addition, the green sheet obtained by applying the slurry and drying is held on the release film obtained by applying the release layer to the biaxially oriented polyester film for mold release of the second invention, and is wound up. As mentioned above, the shape of the surface of the C' layer affects the surface morphology of the green sheet after winding. In other words, by setting the ten-point average roughness SRa (C') of the surface of the C' layer to 600 nm, it is possible to suppress the occurrence of pits or pinholes on the surface of the rolled green sheet, and it is possible to suppress the occurrence of pressure failure of the ceramic capacitor.

A preferred embodiment of the biaxially oriented polyester film for mold release according to the second aspect of the invention is a biaxially oriented polyester film for mold release, wherein the A' layer has a thickness of 3.0 μm or more and 8.0 μm or less, A' The particles contained in the layer have a volume average particle diameter (dA') of 0.1 μm or more and 1.0 μm or less, and 0.05% by weight or more and 1.0% by weight or less based on the weight of the A' layer; and a B' layer thickness of 10.0 μm or more and 35.0 μm. In the following layer, the particles contained in the B' layer have a volume average particle diameter (dB') of 0.2 μm or more and 1.5 μm or less, and the inorganic particles are 0.6 to 6% by weight based on the weight of the B' layer, and the organic particles are relative to the B' layer. The weight of the B' layer is 0.05 to 5% by weight; the layer having a C' layer thickness of 0.5 μm or more and 2.0 μm or less, and the particles contained in the C' layer have a volume average particle diameter (dC') of 0.2 μm or more and 1.0 μm or less. And containing 0.03 wt% or more and less than 1.0 wt% with respect to the weight of the C' layer; the volume average particle diameter of the particles contained in the A' layer, the B' layer, and the C' layer is in the relationship of the formula (1'), and the entire layer The thickness is 20 μm or more and 40 μm or less; dA'<dC'≦dB'... Formula (1').

If the volume average particle diameters dA', dB', and dC' of the particles added to the A' layer, the B' layer, and the C' layer are in the relationship of dA'<dC'≦dB', and each A' layer, B' layer When the C' layer contains particles having the above particle diameter in the above range, the impact of the green sheet during punching can be relaxed, and the heat dispersion or pressure dispersion in the green sheet layer can be adjusted in an appropriate range, thereby improving the green sheet punching. The properties of the cut and the green sheet are preferred.

When the formula (1') is satisfied, it is preferable to satisfy the balance between the coatability of the ceramic slurry at the time of forming the green sheet and the green sheet punching property and the green sheet layering property.

In the B' layer of the biaxially oriented polyester film for mold release according to the second aspect of the invention, the edge portion (film) produced in the film forming step of the film of the second invention is transmitted within a range that does not impair the effects of the second invention. The tantalum film produced in the width direction end portion or the other film forming step is appropriately mixed and used as a recycled raw material (recovered raw material), and a cost advantage can be obtained. In general, in the manufacturing step of the film, there is a step of holding a clip in the width direction of the film to travel. At this time, in order to wind up the intermediate product, since the aforementioned grip portion has a significant thickness unevenness, it is trimmed and removed. The rolled intermediate product is then cut (cut) along the width of the product to obtain a roll of the product. The end of the cut (cut) processed intermediate article has not yet become an article. Here, since the above-mentioned jig grip portion is subjected to thermal influence greatly, and crystallization proceeds continuously, it is preferable to add only the chips generated in the step after the intermediate product having a low crystallization state is rolled up. Since the efficiency of drying the raw material is deteriorated due to the shape or bulk density of the recovered raw material, and the discharge in the extrusion step is unstable, the blending of the raw material added to the layer B with respect to the raw material of the entire layer B is blended. The rate is adjusted to suit the suitability of such drying or extrusion steps. Further, the desired amount is adjusted so as to control the haze described later to a preferable value. Preferably, the heat history before the recovery of the raw material is homogenized. For example, if the unaligned film and the biaxially stretched film are mixed and recovered, the melt viscosity is unstable due to the difference in crystallinity, and the green sheet is rushed. The change in sex is changed. Further, if a difference in melting point occurs at the time of remelting, and an unmelted impurity or a thermally deteriorated impurity is generated, the impurity forms a coarse protrusion. When the coarse protrusions are larger than the layer thickness of the A' layer or the C' layer, coarse protrusions are formed on the surface of the A' layer or the C' layer. At this time, particularly when a surface protrusion is formed on the side of the A' layer, pinholes of the green sheet are generated.

In the biaxially oriented polyester film for mold release according to the second aspect of the invention, it is preferred that the particles contained in the C' layer have one or two peaks in the particle size distribution curve. In the biaxially oriented polyester film for mold release according to the second aspect of the invention, in the step of producing a multilayer ceramic capacitor, a support for forming a green sheet is formed by forming a release layer on the surface of the layer A', and on the release layer. After the green sheet is held, it is rolled up. After being rolled up, the surface of the C' layer is crimped to the green sheet due to the effect of the winding. At this time, the surface shape produced by the projections on the surface of the C' layer was transferred to the green sheet. The transfer marks at this time affect the morphology of the green sheet and affect the dielectric constant of the capacitor. In order to prevent such a transfer mark from being attached to the green sheet, it is preferable that the pressure on the surface of the C' layer is uniformly dispersed while being pressed against the surface of the green sheet. For this reason, the height of the protrusions formed on the flat surface of the surface of the C' layer is preferably uniform.

Further, the protrusion on the surface of the C' layer causes a problem of hooking the surface of the green sheet to wind the green sheet when the green sheet is wound up. Such hooking can be achieved by uniformizing the height of the projections formed on the flat surface of the surface of the C' layer. And prevent it.

Further, the protrusions on the surface of the C' layer can also prevent agglomeration of the green sheets from the surface of the C' layer. In the highly smooth release film which can form a green sheet of a film, the green sheet is liable to come into contact with a flat surface on the surface of the C' layer where no protrusion is formed. When the peak of the particle size distribution of the particles contained in the C' layer is one, the contact with the green sheet is most uniform, but the flat surface of the C' layer is easily adhered to the green sheet. Further, the adhesion between the surface of the C' layer and the green sheet is too uniform, and excessive peeling force is required at the initial stage of peeling. At this time, when a portion having a weak microscopic peeling force is formed, the portion becomes a starting point of peeling, and peeling is easily performed at the initial stage of peeling. The present inventors have found that in order to form the surface of the C' layer to be easily peeled off at the initial stage of peeling, it is possible to form the particles contained in the C' layer into particles having two peaks in the particle size distribution curve. However, when the particles contained in the C' layer have more than three peaks in the particle size distribution curve, the height difference between the protrusions is uneven, and the dispersion of the pressure is too disordered to cause excessive pressure on a certain portion.

Further, by performing surface treatment using a surfactant or the like on the particles, it is preferable to improve the affinity with the polyester and to form protrusions having less peeling.

The sum of the fracture strength in the longitudinal direction and the transverse direction of the biaxially oriented polyester film for mold release according to the second aspect of the invention is preferably 500 MPa or more and 600 MPa or less, more preferably 520 MPa or more and 590 MPa or less. Further, the breaking strength in the width direction is preferably equal to or higher than the breaking strength in the longitudinal direction, and the difference (the breaking strength in the width direction - the breaking strength in the longitudinal direction) is preferably 0 MPa or more and 90 MPa or less, more preferably 40 MPa or more and 80 MPa or less. . When the sum of the rupture strengths in the longitudinal direction and the transverse direction is 500 MPa or more, it is easy to present Now, in the extension step, the polymer around the particles is separated from the particles by a void (void) structure, and the center line roughness or cushioning property of the desired surface is well exhibited. Further, in order to achieve a state in which the sum of the breaking strengths in the longitudinal direction and the transverse direction is higher than 600 MPa, it is necessary to perform excessive stretching in the longitudinal direction or the width direction, so that cracking is not preferable in the stretching.

Further, the elongation in the longitudinal direction and the transverse direction is preferably 80% or more and 220% or less, more preferably 90% or more and 210% or less. Further, the rupture elongation in the longitudinal direction is preferably equal to or higher than the rupture elongation in the width direction, and the difference (the rupture elongation in the longitudinal direction - the rupture elongation in the width direction) is 0% or more and 100% or less. good. In addition, the elongation at break in the longitudinal direction is 170% or more and 190% or less, the elongation at the width direction is 90% or more and 110% or less, and the rupture elongation in the longitudinal direction is 70% or more and 90% larger than the rupture in the width direction. The following is better. When the tensile strength in the longitudinal direction and the transverse direction is 80% or more, it is preferable to absorb the tension in the step when the ceramic slurry is applied, and to suppress the occurrence of unevenness in coating. Further, the rupture elongation in the longitudinal direction or the transverse direction is set to 220% or less, and when the release layer is applied and stored, it is possible to suppress the deterioration of the planarity. Further, when the ceramic slurry is applied and stored, it is possible to suppress the deterioration of the planarity of the green sheet. By controlling the rupture elongation within the above range, it is possible to control the phenomenon of stretching and contraction of the film due to the tension experienced in the processing step, or the behavior of residual stress recovery after winding, and finally the green sheet of the film can be well preserved. Flatness. Further, the reason why the rupture elongation in the longitudinal direction is equal to or higher than the rupture elongation in the width direction is preferably as follows: in the step of applying the release layer and the winding step, tension is applied to the longitudinal direction of the film; In the shape of the film internal stress after rolling up Residue. Thereafter, when tension is applied in the longitudinal direction, the film in the width direction is changed in size due to the deformation of Paisson. The dimensional change in the width direction causes planarity defects when the film roll coated with the release layer is wound up. In order to suppress the dimensional change, it is preferable that the elongation in the longitudinal direction is equal to or higher than the fracture elongation in the width direction, and the difference in the elongation in the longitudinal direction and the width direction is within the above range.

Further, the biaxially oriented polyester film for mold release according to the second aspect of the invention preferably has a haze of 7% or less, more preferably 6% or less. As a mold release application of the laminated ceramic capacitor, the recovered raw material can be added to the intermediate layer of the three-layer composite layer. However, when the haze exceeds 7%, the state of the green sheet is not easily confirmed, and the state of the end portion is particularly poor.

Furthermore, the thickness unevenness in the longitudinal direction of the polyester film of the second invention is preferably 2 μm or less. Further, in the second invention, the thickness unevenness in the longitudinal direction is measured by measuring the thickness of the film of 15 m in the longitudinal direction of the film, and the thickness of the film is recorded, and the difference between the maximum thickness and the minimum thickness of the film is obtained. It is preferably 1.4 μm or less. In order to reduce the thickness unevenness of the film, it is a problem in the production of a film. However, in order to apply the film for mold release of the second invention, a release film suitable for the manufacture of a film ceramic capacitor is used, and the thickness unevenness in the longitudinal direction is made. Within the above range, it is preferred that the electrostatic capacity of the capacitor does not change when the thickness of the green sheet is reduced.

In the polyester film of the second aspect of the invention, the coarse protrusions having a height of 0.27 μm or more on the surface of the A' layer of the film are preferably 5 pieces/100 cm ² or less. Further, the coarse protrusions of 0.54 μm or more are preferably one/100 cm ² or less. More preferably, the coarse protrusions of 0.54 μm or more are substantially absent. When the number of the coarse protrusions is set within the above range, when the release agent is applied, coating unevenness and pinhole-like coating peeling can be suppressed. Further, it is possible to suppress the occurrence of peeling unevenness of the green sheet due to the application of the release agent peeling off when the thickness of the green sheet is reduced. Further, it is possible to suppress the occurrence of pits or pinholes in the green sheets due to the coarse protrusions.

In order to achieve the above-described preferred embodiment of the coarse protrusions on the surface of the film, the particle type and the volume average particle diameter contained in the A' layer, the B' layer, and the C' layer are in the above range. In addition, the apparatus for supplying the raw material of the polyester film of the second invention, in particular, the raw material storage device (storage bin) and the piping for the transportation of the raw material are used only for the main pellet containing the particles used in the second invention. The pellets are transported in the following manner. In order to transport raw materials, they are transported by air using a blower or by free fall. However, when transporting by air, it is preferable to use 95% of 0.3 μm or more when the air is taken in. The dust filter filters the air. In addition, the filter used in the manufacture of the second invention can be achieved by using a high-precision filter to be described later.

In the polyester film of the second aspect of the invention, the dimensional change rate is appropriately controlled, and the post-processing is favorably maintained, and in particular, the planarity after the release of the release layer is preferable. The method of setting the dimensional change rate within the range described later can be achieved by appropriately adjusting a known method such as relaxation treatment in the film formation conditions. The dimensional change rate at 150 ° C is preferably 2% or less in the longitudinal direction, 2.5% or less in the width direction, more preferably 0.5% or more and 1.7% or less in the longitudinal direction, and 1% or more and 2% or less in the width direction. Further, the dimensional change ratio at 100 ° C is preferably 1% or less in the longitudinal direction and the width direction, and more preferably in the range of 0.2% or more and 0.8% or less. The size change If the chemical conversion rate is lower than the lower limit of the above range, the planarity defect due to relaxation may occur when the release layer is applied; when the release layer is applied, the shrinkage unevenness due to shrinkage during coating of the release layer may result in poor planarity. In either case, the coating thickness of the green sheet of the film is not uniform.

Next, a method of producing the biaxially oriented polyester film of the second invention will be described. As a method of containing the inert particles in the polyester, for example, the inert particles are dispersed in a predetermined ratio in the form of a slurry in ethylene glycol as a diol component, and the ethylene glycol is added at any stage before the polymerization of the polyester is completed. Slurry. When the particles are added, for example, when the hydrosol or the alcohol sol obtained in the case of the synthetic particles is not temporarily dried, the dispersibility of the particles is good, and generation of coarse protrusions can be suppressed. Further, a method in which the water slurry of the particles is directly mixed with a predetermined polyester pellet and then supplied to a vented biaxial kneading extruder to be incorporated into the polyester is also effective for the production of the second invention.

In this manner, the pellets for the main pellets, the particles, and the like which are prepared for the respective layers and which are substantially free of particles are mixed and dried, and then supplied to a known melt laminating extruder. In the extrusion machine for producing a biaxially oriented polyester film for mold release according to the second aspect of the invention, a single-axis or two-axis extruder can be used. Further, in order to omit the drying step of the pellets, a vented extruder equipped with an evacuation line in the extruder may be employed. Further, for the B' layer having the largest amount of extrusion, a so-called tandem extruder which functions to melt the pellets and maintain the function of the molten pellets at a constant temperature by the respective extruders can be used. In the A' layer and the C' layer of the biaxially oriented polyester film for mold release according to the second aspect of the invention, it is preferred to use a biaxial vent type extruder because the dispersibility of the particles can be favorably maintained.

The melted, extruded polymer in the extruder is filtered using a filter. When extremely small impurities are also mixed into the film, coarse protrusions are caused. Therefore, it is effective to use a high-precision filter which can capture, for example, 95% or more of impurities of 3 μm or more. Subsequently, it was extruded into a sheet shape from a slit-shaped slit die, and cooled and solidified on a casting roll to form an unstretched film. That is, three extruders, three layers of manifolds or confluence blocks (for example, confluence blocks having rectangular confluences) are laminated into three layers, and then the sheets are extruded from the nozzles and cooled by the casting rolls to form Extend the film. At this time, it is effective to provide a static mixer and a gear pump in the polymer flow path from the viewpoint of stabilizing the back pressure and suppressing the thickness variation.

The extension method can be simultaneous biaxial extension or sequential biaxial extension. In particular, in the simultaneous biaxial stretching, the extension by the use of the roller is not accompanied, so that local uneven heating of the surface of the film can be suppressed, uniform quality can be obtained, and the film and the roll which are generated by the extension of the roller during stretching can be suppressed. It is preferable that the speed difference at the contact portion, the transfer of minute scratches of the roller, and the like are generated.

In the simultaneous biaxial stretching, the unstretched film is first extended in the length and width directions by an extension temperature of 80 ° C or more and 130 ° C or less, preferably 85 ° C or more and 110 ° C or less. When the stretching temperature is lower than 80 ° C, the film is easily broken, and when the stretching temperature is higher than 130 ° C, sufficient strength cannot be obtained. Furthermore, based on the idea of preventing uneven extension, the length direction. The total stretching ratio in the width direction is 4 times or more and 20 times or less, preferably 6 times or more and 15 times or less. When the total stretching ratio is less than 4 times, it is difficult to obtain sufficient strength. On the other hand, when the magnification is more than 20 times, the film is liable to be broken and it is not easy to manufacture a stable film. To get the strength you need The degree is preferably 140 ° C or more and 200 ° C or less, preferably 160 ° C or more and 190 ° C or less in the longitudinal direction and/or the width direction by 1.02 times or more and 1.5 times or less, preferably 1.05 times or more and 1.2 times or less. In the longitudinal direction, the total stretching ratio is 3 times or more and 4.5 times or less, preferably 3.5 times or more and 4.2 times or less, and 3.2 times or more and 5 times or less in the width direction, preferably 3.6 times or more and 4.3 times or less. In order to achieve the target film breaking strength, the magnification can be appropriately selected, and in order to increase the breaking strength in the width direction, it is preferable to set the stretching ratio in the width direction to be slightly higher than the length direction. Thereafter, it is thermally fixed at 205 ° C or higher and 240 ° C or lower, preferably 220 ° C or higher and 240 ° C or lower for 0.5 second or longer and 20 seconds or shorter, preferably 1 second or longer and 15 seconds or shorter. When the heat setting temperature is lower than 205 ° C, the thermal crystallization of the film does not proceed, so that the dimensional change rate of the target is difficult to achieve stability. Further, in order to stabilize the physical properties of the film, the temperature difference between the upper and lower sides of the film is 20 ° C or lower, preferably 10 ° C or lower, more preferably 5 ° C or lower. When the temperature difference between the upper and lower sides of the film is more than 20 ° C, it is liable to cause a slight deterioration in planarity during heat treatment. Thereafter, a relaxation treatment of 0.5% or more and 7.0% or less is carried out in the length and/or width direction.

At the same time, the biaxial stretching is different from the successive biaxial stretching described later, and the film is heated by high temperature air. Therefore, it is not only that the surface of the film is locally heated to cause adhesion, and it is more preferable to extend it as a stretching method.

On the other hand, the polyester film of the second invention can also be produced by sequential stretching.

The extension of the first longitudinal direction is extremely important for suppressing the generation of scratches, and the elongation temperature is 90 ° C or more and 130 ° C or less, preferably 100 ° C or more and 120 ° C or less. When the extension temperature is lower than 90 °C, the film is easily broken and extended. When the temperature is higher than 130 ° C, the surface of the film is susceptible to thermal damage. Further, based on the viewpoint of preventing unevenness of extension and damage, the extension is preferably carried out in two or more stages, and the total magnification is three times or more and 4.5 times or less in the longitudinal direction, preferably 3.5 times or more and 4.2 times or less. The width direction is 3.2 times or more and 5 times or less, preferably 3.6 times or more and 4.3 times or less. In order to achieve the target film breaking strength, the magnification can be appropriately selected, and in order to increase the breaking strength in the width direction, it is preferable to set the stretching ratio in the width direction to be slightly higher than the length direction. If the temperature and the range of the magnification are exceeded, problems such as uneven stretching or film breakage may occur, and it may be difficult to obtain a film which is characterized by the second invention. After the vertical or horizontal stretching is performed again, the heat is fixed at 205 ° C or higher and 240 ° C or lower, preferably 210 ° C or higher and 230 ° C or lower, and 0.5 seconds or longer and 20 seconds or shorter, preferably 1 second or longer and 15 seconds or shorter. In particular, when the heat setting temperature is lower than 205 ° C, the crystallization of the film does not proceed so that the structure is unstable, and the characteristics such as the dimensional change rate of the target cannot be obtained.

In the successive stretching, the length direction extending process is preferably a step of contacting the film with the roller, and the scratch is easily caused by the difference between the peripheral speed of the roller and the speed of the film, and the driving speed of the roller peripheral speed can be individually set for each roller. . During the extension of the length direction, the material of the transport roller is transported to the extension zone in accordance with the state in which the unstretched film is heated above the glass transition point before stretching or at a temperature less than the glass transition point and is extended. It is selected by heating, and when the unstretched film is heated to a temperature above the glass transition point before stretching, it can be selected from non-adhesive silicone resin rolls, ceramics, TEFLON (registered trademark) in terms of preventing adhesion by heating. In addition, in the case of the stretching roller, the step of stretching the surface of the roller for the step of applying the most load to the film and easily causing scratches or uneven stretching during the process The center line roughness Ra is 0.005 μm or more and 1.0 μm or less, preferably 0.1 μm or more and 0.6 μm or less. When Ra is larger than 1.0 μm, the unevenness of the surface of the roll may be transferred to the surface of the film when it is extended; on the other hand, when it is less than 0.005 μm, the roll adheres to the surface layer of the film, and the film is liable to be damaged by heat. In order to control the center line roughness of the surface of the stretching roller, it is effective to appropriately adjust the particle size of the abrasive, the number of grinding, and the like. The transport roller of the preheating zone is preferably surface treated with hard chrome or tungsten carbide when transported to the extension zone while maintaining the unstretched film at a temperature less than the glass transition point. The metal roll having a center line roughness Ra of the surface of the stretching roll of 0.2 μm or more and 0.6 μm or less.

In the biaxially oriented polyester film for mold release according to the second aspect of the invention, the uniaxially stretched film extending in the longitudinal direction is heated to 80° C. or more and less than 120° C. by a transverse stretching machine, and is preferably 3 times or more and less than 6 times. The film is extended in the width direction to form a biaxially oriented (biaxial alignment) film.

The biaxially oriented polyester film for mold release according to the second aspect of the invention can be further extended in each direction by one or more times, or can be further extended on both sides. Further, the heat treatment of the film is carried out after the biaxial stretching, but the heat treatment may be carried out by any conventionally known method such as in an oven or a heating roll. The heat treatment temperature can be generally set to any temperature of from 150 ° C to less than 245 ° C, and the heat treatment time is preferably from 1 second to 60 seconds. The heat treatment can also be carried out by allowing the film to relax in the longitudinal direction and/or the width direction. Further, after the heat treatment, the temperature is lowered by 0% or more and 10% or less in the width direction at a temperature lower than the heat treatment temperature by 0 ° C to 150 ° C.

The heat treated film can be provided, for example, by providing an intermediate cooling zone Or remove the cold zone to adjust the dimensional change rate or planarity. Further, in particular, in order to impart a specific heat shrinkability, it may be relaxed in the longitudinal direction and/or the transverse direction during the heat treatment or the intermediate cooling zone or the decooling zone thereafter.

The biaxially stretched film is cooled in the transporting step, and then the edge is cut off and then rolled up to obtain an intermediate product. In this transport step, the thickness of the film is measured, the data is fed back, the data is used, and the thickness of the film is adjusted by adjustment of the thickness of the mold or the like, and the impurity is detected by a helium detector.

In the case of cutting the edge, it is necessary to suppress the generation of chips for the biaxially oriented polyester film for demolding of the second invention. The cutting of the edge is performed by using a round blade, a cutting edge, and a straight edge. When a straight blade is used, the portion where the blade portion contacts the film is not always the same portion, and the blade portion can be suppressed from being worn. Therefore, it is preferable to have an oscillation mechanism. Further, it is preferable to provide a suction means at the film cutting portion for sucking the generated chips or the chips generated by cutting the ends of the cut film from each other.

The intermediate product is cut to the appropriate width by the cutting step. The roll of the biaxially oriented polyester film for mold release of the second invention was obtained by winding up the length. At the time of cutting the film in the cutting step, it may be selected from the same cutting method as the cutting of the aforementioned edge.

The intermediate product was cut into a desired width to obtain a biaxially oriented polyester film for mold release according to the second invention.

[Examples]

Hereinafter, the present invention will be described in detail by way of examples. In the examples, the "A layer, the B layer, and the C layer" refer to the A layer, the B layer, the C layer of the first invention, and the A' layer, the B' layer, and the C' layer of the second invention.

The measurement method and evaluation method related to the present invention are as follows.

(1) Determination of the peak size and particle size distribution of particles

The plasma ashing process removes the polymer from the film to expose the particles. The processing conditions are those in which the polymer can be ashed but the particles are not severely damaged. The particles were observed by a scanning electron microscope (SEM; S-4000 model manufactured by Hitachi, Ltd.), and the particle image was taken up to Image Analyzer (LUZEX_AP manufactured by NIRECO Co., Ltd.), and the equivalent circle diameter was measured to obtain particles. Volume average particle size. The SEM magnification is determined by the particle size, and is appropriately selected from 5,000 to 20,000 times. The observation site was arbitrarily changed, and the equivalent circle diameter of the particle diameter of at least 5,000 particles was measured, and the volume average particle diameter was determined from the average value thereof.

When the particles are greatly damaged by the plasma low-temperature ashing method, a transmission electron microscope (TEM; H-600 model manufactured by Hitachi, Ltd.) is used, and the film profile is observed at 3,000 to 20,000 times according to the particle diameter. . The slice thickness of the TEM was set to about 100 nm, and the equivalent circular diameter of at least 100 or more particles was measured at the conversion site, and the volume average particle diameter d was obtained from the average value thereof.

In addition, when the volume average particle diameter of the particles was measured, it was judged that the particles were substantially absent when the presence of the particles was not observed by 5,000 and 10 fields of view by SEM and TEM observation.

Further, the peak of the particle size distribution curve of the particles is determined by the image analyzer, and the volume average particle diameter is "more than 0 μm and 0.2 μm or less, more than 0.2 μm and 0.4 μm or less, more than 0.4 μm and 0.6. The mode below μm..." is classified every 0.2μm, and When counting the number of particles, if there is a total number of 20% or more, it is regarded as one peak. Count the peak to determine.

(2) Volume shape factor of particles

The photograph of the particles is photographed by, for example, 5000 times and 10 fields using a scanning electron microscope, and then the maximum diameter of the projection surface and the average volume of the particles are calculated using a video analysis processing device, and the volume shape coefficient is obtained according to the following equation.

f = V / Dm ³

Here, V is the average volume (μm ³ ) of the particles, and Dm is the maximum diameter (μm) of the projection surface.

(3) Mohs hardness and cross-linking degree

<Mohs hardness>

A test piece having the same composition and structure as that of the particles added to the film or a mineral before being pulverized into particles is used as a test piece, and is scraped from each other with a standard mineral for measuring Mohs hardness, and is measured according to whether or not scratching can be performed. The standard minerals are as follows: Mohs hardness 1: talc, Mohs hardness 2: gypsum, Mohs hardness 3: calcite, Mohs hardness 4: fluorite (Fluorite), Mohs hardness 5: apatite (Apatite) Mohs hardness 6: Moonstone, Mohs hardness 7: Quartz, Mohs hardness 8: Topaz, Mohs hardness 9: Emery, Mohs hardness 10: Diamond.

<degree of crosslinking>

The degree of crosslinking of the present invention is determined by the following formula.

Crosslinking degree (%) = (weight of cross-linking component in raw material monomer) / (total weight of raw material monomer) × 100

(4) Intrinsic viscosity

The value obtained by the following formula was calculated based on the viscosity of the solution measured at 25 ° C in o-chlorophenol. That is, ηsp/C=[η]+K[η] ² . C

Here, ηsp = (solution viscosity / solvent viscosity) ^-1 , C is the weight of the dissolved polymer per 100 ml of the solvent (g / 100 ml, usually 1.2), and K is the Huggins constant (take 0.343). Moreover, the solution viscosity and the solvent viscosity were measured using an Oswald viscometer. The unit is expressed in [dl/g].

(5) Thickness of film laminate

A cross section of the film was observed by a transmission electron microscope (TEM; H-600 type manufactured by Hitachi Co., Ltd.) at an acceleration voltage of 100 kV and an ultrathin section (RuO ₄ dyeing). The total thickness is obtained from the entire section, and the thickness of the layer is determined by the depth of the surface at the deepest point of the particle observed at the interface, that is, the thickness of the layer. Regarding the magnification, the magnification may be appropriately set according to the total thickness of the film to be tested and the layer thickness. Generally, the total thickness is suitably 1000 times and the thickness of the layer is suitably 10,000 to 100,000 times.

When the number of particles is small, etc., in order to discriminate the laminated interface, it is preliminarily assumed at what magnification the particle image should be obtained. For this reason, it is more effective to carry out the layering assumed by the element distribution (mapping) of the profile by the SEM-XMA of the profile. The estimated thickness is used to determine the set magnification of the TEM.

(6) Burst elongation and burst strength

According to JIS C2151-1990, it was measured by an Instron type tensile tester (ORIENTEC automatic film thickness measuring device "TENSILON" universal testing machine RTC-1210). For a sample film with a width of 10 mm, the specimen length is 100 mm and the tensile speed is 200 mm/min. The tensile test was carried out, and the stress at the time of film rupture was determined as the fracture strength, and the strain (elongation) at the time of film rupture was determined as the rupture elongation. The measurement was carried out at 23 ° C and a humidity of 65% RH.

(7) Dimensional change rate

Two lines were drawn on the surface of the film so as to have a width of 10 mm and a length of about 100 mm, and the distance between the two lines was accurately measured at 23 ° C, which was L0. The film sample was placed in an oven at 100 ° C or 150 ° C for 30 minutes, and placed under a load of 1.5 g, and then the distance between the two lines was measured again at 23 ° C, which was L1, and each of them was obtained according to the following formula. The rate of dimensional change at temperature.

The dimensional change rate (%) = {(L0 - L1) / L0} × 100.

(8) Center line roughness (SRa value) of the film surface

The contour curve of the surface obtained by measurement using a three-dimensional fine surface shape measuring instrument (ET-350K manufactured by Otaru Seisakusho Co., Ltd.) is based on JIS. B0601 (1994), the arithmetic mean roughness SRa value is obtained. The measurement conditions were as follows: length in the X direction: 0.5 mm, and conveying speed in the X direction: 0.1 mm/sec.

Y-direction transmission pitch: 5μm, Y-direction line number: 40.

Intercept value: 0.25mm.

Stylus pressure: 0.02 mN.

Height (Z direction) magnification: 50,000 times.

(9) Number of large protrusions

For the number of coarse protrusions, the measurement surfaces of two 10 cm square films are overlapped with each other, and the applied voltage is adhered by electrostatic force, and the height is estimated based on the interference fringes generated by the coarse protrusions on the surface of the film. . The number of coarse protrusions of the first ring of 0.270 μm, the second ring of 0.540 μm, and the third ring of 0.810 μm or more was measured. As the light source, a band pulse filter having a band of 564 nm is attached to the halogen lamp.

(10) Thickness unevenness in the length direction

The thickness of the 15 m film was measured along the length of the film and was determined from the difference between the maximum thickness and the minimum thickness of the film from the recorded film thickness map.

The thickness of the 15 m film was measured along the length direction of the film by using an Anisoelectric film thickness continuous measuring device, and the difference between the maximum thickness and the minimum thickness was measured as the thickness unevenness (μm) from the recorded film thickness map. The measurement conditions were as follows: Construction: K-306C wide-range electronic micrometer, K-310C Recorder, film transfer device.

Film width: 45 mm, measuring length: 15 m, film conveying speed: 3 m/min

Detector: 3R ruby (ruby) terminal, measuring force: 15 ± 5g.

(11) Film haze

According to JIS K7105-1981, a length of 4.0 cm × a width of 3.5 cm was cut out from the center of the film width direction, and the haze was measured by a haze meter (Suga test mechanism HGM-2DP (for C light source)). .

[Example 1]

(1) Preparation of polyester pellets

(production of polyester A)

86.5 parts by weight of p-citric acid and 37.1 parts by weight of ethylene glycol at 255 ° C Next, the water was distilled off while the esterification reaction was carried out. After completion of the esterification reaction, 0.02 parts by weight of trimethylphosphoric acid, 0.06 parts by weight of magnesium acetate, 0.01 parts by weight of lithium acetate, and 0.0085 parts by weight of antimony trioxide were added, followed by heating to 290 ° C under vacuum, and heating was carried out to carry out a polycondensation reaction. A polyester pellet A having an intrinsic viscosity of 0.63 dl/g was obtained.

(Preparation of polyester B and polyester C)

When polyester is produced in the same manner as above, a spherical cerium oxide having a volume average particle diameter of 0.2 μm, a volume form factor of f = 0.51, and a Mohs hardness of 7 is added to the polyester B after the transesterification, and the polyester C is added. a spherical cerium oxide having a volume average particle diameter of 0.06 μm, a volume form factor of f = 0.51, and a Mohs hardness of 7 and undergoing a polycondensation reaction to obtain a cerium oxide-containing main pellet containing particles of 1% by weight based on the polyester. (Polyester B), (Polyester C).

Further, the spherical cerium oxide used in the polyester B and the polyester C is a mixture of ethanol and ethyl citrate, and the mixed solution contains ethanol, pure water, and an alkaline catalyst. The mixed solution of ammonia water is stirred, and the hydrolysis reaction of ethyl citrate and the polycondensation reaction of the hydrolysis product are carried out, and then the reaction is stirred and the monodisperse cerium oxide particles are obtained.

(Production of polyester D, E and polyester F)

Further, a seed crystal size obtained by a seed method comprising 80% by weight of divinylbenzene (crosslinking component), 15% by weight of ethylvinylbenzene, and 5% by weight of styrene having a volume average particle diameter of 0.3 μm and a volume form factor f = 0.51, Mohs hardness 3 bis ethylene benzene / styrene copolymerized crosslinked particles (degree of crosslinking 80%) aqueous slurry, blended in the above-mentioned substantially particle-free by a ventilated biaxial kneader Tongyuan polyester pellets, which are obtained with 1 relative to polyester The main pellet (polyester D) of divinylbenzene/styrene copolymerized crosslinked particles having a volume % of a volume average of 0.3 μm by weight.

The main pellets containing divinylbenzene/styrene copolymerized crosslinked particles having a volume average particle diameter of 0.8 μm, a volume form factor of f = 0.51, and a Mohs hardness of 3 with respect to 1% by weight of the polyester were obtained in the same manner ( Polyester E), main pellet containing divinylbenzene/styrene copolymerized crosslinked particles having a volume average particle diameter of 0.1 μm, a volume form factor of f=0.51, and a Mohs hardness of 3 with respect to polyester ( Polyester F).

(production of polyester G)

10 parts by weight of calcium carbonate particles (Mohs hardness 3) and 90 parts by weight of ethylene glycol were wet-pulverized to obtain a calcium carbonate/ethylene glycol dispersion slurry (A). The volume average particle diameter of the calcium carbonate was 1.1 μm. Further, 0.04 parts by weight of manganese acetate as a catalyst and 0.03 parts by weight of antimony trioxide were added to 100 parts by weight of dimethyl perruthenate and 64 parts by weight of ethylene glycol, and then the reaction product was added. 0.04 parts by weight of a trimethylphosphine as a phosphorus compound, and further, 1 part of the previously prepared slurry (A) is subjected to a polycondensation reaction to obtain a main pellet containing 1% by weight of calcium carbonate relative to the polyester. Granules (polyester G).

On the other hand, a film obtained by producing a film of the following formulation is recovered and pelletized, and this is used as the recovered raw material A. In addition, the ratio described below is represented by the weight ratio (weight%) with respect to the weight of the whole film.

Polyester A: 93.4

Polyester D: 0.6

Polyester G: 6.0.

(2) blending of polyester pellets

The polyester pellets supplied to the extruder in each of the layers A, B, and C were blended in the following ratios. Moreover, the ratio described below is a weight ratio (unit: weight%) with respect to the polyester pellet which comprises each layer.

A layer

Polyester A: 87.5

Polyester B: 12.5

B layer

Polyester A: 60.0

Recycling raw material A: 40.0

C layer

Polyester A: 65.0

Polyester C: 30.0

Polyester D: 5.0.

(3) Manufacture of biaxially oriented polyester film

After the raw materials blended for the respective layers are stirred in the blender, the raw materials of the A layer and the C layer are supplied to the aerated hole (vented) biaxial extruder for the A layer and the C layer. The raw material of the layer B was dried under reduced pressure at 160 ° C for 8 hours, and supplied to a uniaxial extruder for the layer B. After being melt-extruded at 275 ° C and filtered by a high-precision filter capable of trapping impurities of 95 μm or more and 3 μm or more, a layer of a layer A is formed by laminating a layer of a different type of three-layer junction block having a rectangular shape. Layer 3 of layer B and layer C. Thereafter, the casting drum was rolled up to a casting temperature of 25 ° C on the cooling roll by a slit die held at 285 ° C by an electrostatic application casting method, and cooled and solidified to obtain an unstretched laminated film.

The unstretched laminated film is sequentially extended (length direction, width direction). First, the extension in the longitudinal direction was carried out, and after transporting the film roll at TEFLON (registered trademark) at 105 ° C, a uniaxially stretched film was formed by stretching 4.0 times in the longitudinal direction at 120 ° C.

The uniaxially stretched film was stretched four times in the tenter toward 115° C. transversely, and then heat-set at 230° C., at which time it was relaxed by 5% in the width direction and cooled in the transporting step, and then the edge was cut. Thereafter, it was rolled up to obtain an intermediate product of a biaxially stretched film having a thickness of 38 μm. The intermediate product was cut with a slitter to obtain a roll of a biaxially stretched film having a thickness of 38 μm. The thickness of the laminate of the biaxially stretched film was measured and found to be A layer: 6.5 μm, B layer: 30.5 μm, and C layer: 1.0 μm.

(4) Coating of the release layer

Next, the roll of the biaxially stretched film was coated with a coating liquid having a crosslinked primer layer (trade name BY24-846, manufactured by Toray Dow Corning Silicone Co., Ltd.) adjusted to a solid content of 1% by weight, and dried to obtain a gravure The coater was applied to a coating thickness of 0.1 μm after drying, and dried and hardened at 100 ° C for 20 seconds. Thereafter, within 1 hour, 100 parts by weight of an addition reaction type epoxy resin (trade name: LTC750A, manufactured by Toray Dow Corning Silicone Co., Ltd.) and 2 parts by weight of platinum catalyst (Toray Dow Corning Silicone) were coated by a gravure coater. The product name SRX212) was adjusted to a coating liquid having a solid content of 5% by weight, and the coating thickness after drying was 0.1 μm, and dried and cured at 120 ° C for 30 seconds, and then rolled up to obtain a release film.

(5) Evaluation of coating state of green sheet (coating property of ceramic slurry)

100 parts by weight of barium titanate (trade name: HPBT-1 manufactured by Fuji TITANIUM Co., Ltd.), 10 parts by weight of polyvinyl butyral (trade name BL-1 manufactured by Sekisui Chemical Co., Ltd.), and 5 parts by weight of dibutyl citrate Adding a glass beads with a number average particle diameter of 2 mm to 60 parts by weight of toluene-ethanol (30:30 by weight), and mixing them by a jet mill. After dispersing for 20 hours, it was filtered to prepare a paste-like ceramic slurry. The obtained ceramic slurry was applied onto a release film by a die coater to a thickness of 2 μm after drying, and rolled up to obtain a green sheet. The green sheet which was wound up by the above-mentioned medium warp was taken out and visually observed without being peeled off from the release film, and the presence or absence of the pinhole, and the application state of the surface and the end of the sheet were confirmed. Furthermore, the observation area is 300 mm in width and 500 mm in length.

a. Whether there are pinholes or pits

The green sheet formed on the release film was irradiated with a backlight unit of 1000 lux from the back side, and the pinholes generated by the application of the peeling of the coating or the surface of the back surface of the release film were observed.

A: No pinholes or pits.

B: There is no pinhole, and it is possible to confirm the pits within three.

C: There are pinholes, and more than 4 pits can be confirmed.

b. The surface of the sheet. End coating state

The green sheet formed on the release film was visually observed on the surface and the end of the sheet.

A: Coating unevenness was not confirmed on the surface and the end of the sheet.

B: There is no uneven coating on the surface of the sheet, but uneven coating is applied at the end.

C: Coating unevenness was confirmed on both the surface and the end of the sheet.

In the first embodiment, the evaluation of the presence or absence of the pinholes and the pits was evaluated as "A" because there were no pinholes or pits. Also, the surface and end of the sheet are both No coating unevenness, so it was rated as "A".

(6) Punching properties of green sheets

After the internal electrode pattern was formed in the following procedure, and the green sheet was subjected to punching and lamination, the characteristics at the time of peeling were evaluated.

a. Formation of internal electrode patterns

44.6 parts by weight of Ni particles, 52 parts by weight of terpineol, 3 parts by weight of ethyl cellulose, and 0.4 parts by weight of benzotriazole were kneaded and slurried to obtain a coating material for an internal electrode layer. The internal electrode layer coating material was applied onto a green sheet by a screen printing method to form a predetermined pattern to obtain a ceramic green sheet having an internal electrode pattern. The drying temperature was 90 ° C and the drying time was 5 minutes.

b. Blanking evaluation of green sheets

The above-described ceramic green sheet formed on the release film and having the internal electrode pattern was taken up, and the green sheet was cut and punched into 100 pieces on the release film. The cutting system uses a rotary round blade. At this time, the cutting depth of the rotary round blade for cutting the green sheet is set to be 2 μm to 3 μm in thickness of the green sheet. At this time, the cut surface of the green sheet after punching on the release film was visually confirmed. In addition, in the evaluation, the round blade was replaced after cutting 1000 pieces.

First, the uniformity of the cut surface was visually confirmed from the upper surface of the green sheet, and the presence or absence of the cut slag or the defect and the presence or absence of peeling from the release film were confirmed. The assessment indicators at this time are as follows:

A: The cut surface of the upper surface of the green sheet has no cutting slag or defects, and there is no partial peeling of the release film from the green sheet.

B: The cut surface of the upper surface of the green sheet was slightly visible with wavy irregularities. There is no partial release of the release film from the green sheet.

C: The cut surface of the upper surface of the green sheet has a cut slag or a defect, or a sheet which is partially peeled off from the green sheet, and occurs in any one piece. There is a possibility of jamming in the laminate of the green sheets, and it is rated as "C".

In Example 1, as a result of the evaluation of the punching property of the green sheet, since the cut surface of the upper surface of the green sheet was free from cutting slag or defects, and no part of the release sheet and the green sheet were peeled off, it was rated as " A".

(7) Green sheet laminate characteristics

The green sheets which were punched out on the release film described above were laminated. The laminate is conveyed in a state in which the green sheet is held on the release film, and the green sheet is thermocompression bonded to the laminate, and then the release film is peeled off. This operation was repeated up to 100 sheets to obtain a ceramic laminate. The laminate state at this time was visually confirmed, and the laminate layer characteristics were evaluated according to the following criteria.

A: In the case of the sheet volume layer, the thermocompression bonding was performed uniformly, so that the green sheet peeling failure did not occur, and the air was stuck or the impurities were caught, and the layer was well laminated.

B: When the sheet volume layer is used, the thermocompression bonding is slightly uneven, and no air is caught, and the peeling state is in an allowable range, but in a rare case, the peeling state is unstable.

C: When the sheet is layered, air is trapped or impurities are caught. Or even a bad peeling occurred.

As a result of evaluating the green sheet laminate characteristics in Example 1, the green sheet peeling failure did not occur at the time of the sheet volume layer, and it was rated as "A".

[Embodiment 2]

A roll of a biaxially stretched film having a thickness of 38 μm was produced in the same manner as in Example 1 except that the particle types added to the A layer and the C layer were changed. Coating of the release layer, molding of the green sheet (coating of the ceramic slurry), formation of a pattern of internal electrodes, evaluation of the punchability of the green sheet, green sheet The layer characteristics were also carried out in the same manner as in the first embodiment. Evaluation (Here, the examples and comparative examples were all carried out in the same processing steps. Evaluation).

The slurry coating characteristics, the green sheet punching property, and the green sheet laminate characteristics were all A, which was good.

[Examples 3, 4]

In the embodiment of the first embodiment, the thickness of each layer was changed, and the type and amount of the particles were adjusted accordingly, and a roll of a biaxially stretched film having a thickness of 38 μm was obtained in the same manner as in Example 1. The ceramic slurry coating characteristics, the green sheet punching property, and the green sheet layering property are all A, which is good.

[Examples 5, 6]

In the embodiment of the first embodiment, the thickness of the C layer is 0.5 μm (Example 7), 2.0 μm (Example 8), and the composition of the A layer is as shown in the table, and the thickness of the A layer is set to 6.5. The thickness of the μm and B layers was set to 31.0 μm (Example 7) and 29.5 μm (Example 8). The coating property of the ceramic slurry was A without any problem. There is no problem in the punchability of the green sheet after the internal electrode pattern. In the peeling step in the case of the green sheet layer, the examples 5 and 6 were not stably peeled off and were B.

[Embodiment 7]

The film obtained in Example 4 was used as the recovered raw material for the B layer (recovered raw material B) in the formulation of the layer B, and the same formulation as in Example 4 was employed for the A layer and the C layer. A roll of a biaxially stretched film having a thickness of 38 μm was obtained in the same manner as in Example 1. The slurry coating characteristics, the green sheet punching property, and the green sheet laminate characteristics were all A, which was good.

[Examples 8, 9]

In Example 2, the total thickness was 31 μm, 25 μm, and the layers A and C were In the same manner as in the second embodiment, the thickness was adjusted by changing the thickness of the layer B. The slurry coating characteristics, the green sheet punching property, and the green sheet laminate characteristics were all A, which was good.

[Examples 10, 11]

A roll of a biaxially stretched film (Example 10) was obtained in the same manner as in Example 1 except that the longitudinal stretching ratio of Example 1 was changed from 4.0 times to 3.3 times. Further, a roll of a biaxially stretched film (Example 11) was obtained in the same manner as in Example 8 except that the longitudinal stretching ratio of Example 8 was changed from 4.0 times to 3.3 times. The slurry coating characteristics, the green sheet punching property, and the green sheet laminate characteristics were all A, which was good.

[Examples 12 and 13]

A roll of a biaxially stretched film having a thickness of 38 μm was produced in the same manner as in Example 1 except that the composition of the A layer, the B layer, and the C layer in Example 1 was changed as described in the Table (Example 12, Example 13). In Example 12, the slurry coating characteristics, the green sheet punching property, and the green sheet layering property were all A, which was good. However, in Example 13, the sheet surface was not coated unevenly but unevenly coated at the ends. Therefore, the evaluation of the surface and end of the sheet coated with the slurry was evaluated as B. In Example 13, both the green sheet punching property and the green sheet layering property were A, which was good.

[Embodiment 14]

When the polyester D is to be obtained, the volume average particle diameter of the film obtained by the seed crystal method containing 40% by weight of divinylbenzene (crosslinking component), 15% by weight of ethylvinylbenzene, and 45% by weight of styrene is 0.3 μm. A water slurry having a shape factor f=0.51, a Mohs hardness of 3, and a vinylbenzene/styrene copolymerized crosslinked particle (degree of crosslinking of 40%) is blended in the above-mentioned substantially by a ventilated biaxial kneader. In the homopolymer polyester pellets without particles. Further, in order to obtain the polyester F, a volume average particle diameter of 0.1 μm containing 40% by weight of divinylbenzene (crosslinking component), 15% by weight of ethylvinylbenzene, and 45% by weight of styrene obtained by the seeding method is obtained. a water slurry having a volumetric shape factor f=0.51, a Mohs hardness of 3, and a vinylbenzene/styrene copolymerized crosslinked particle (degree of crosslinking of 40%), which is blended in the above-mentioned substance by a ventilated biaxial kneader In the homopolymer polyester pellets containing no particles.

In the embodiment of the thirteenth embodiment, the polyester D and the polyester F were used to obtain a roll of a biaxially stretched film. Both the green sheet punching property and the green sheet layering property are A, which is good.

[Comparative Example 1]

In the embodiment of Example 1, a roll of a biaxially stretched film having a thickness of 38 μm was obtained in the same manner as in Example 1 except that the layer A contained substantially no particles.

After the slurry is applied, ripples are generated at the ends of the green sheets after the drying step. When the green sheet is punched, the green sheet is peeled off at the interface of the cut surface. If there is a peeling effect, the green sheet cannot be uniformly layered, which is a poor result.

[Comparative Example 2]

In the embodiment of the first embodiment, a roll of a biaxially stretched film having a thickness of 38 μm was obtained in the same manner as in Example 1 except that the layer B contained substantially no particles.

The slurry coating and the formation of the pattern of the internal electrodes are good, but the cutting of the green sheets is uneven during the punching, and the green sheets are peeled off. The occurrence of a green sheet that cannot be layered is a result of poor performance.

[Comparative Example 3]

In the embodiment of the first embodiment, a roll of a biaxially stretched film having a thickness of 38 μm was obtained in the same manner as in Example 1 in accordance with the formulation in which the layer C was substantially free of particles.

In the winding after the release of the release layer, the winding shape was poor, and the winding tension was adjusted, and the winding hardness of the rolled film of the release film was confirmed, and a release film roll was produced at the same time.

In the coating of the ceramic slurry, the coating end portion is serpentine uneven. After the pattern of the internal electrodes is formed, uneven cutting of the green sheets occurs during the punching, but no peeling of the green sheets occurs. In the case of thermocompression bonding at the time of green sheet deposition, it is not possible to uniformly laminate the layers, which is a poor result.

[Comparative Example 4]

In the embodiment of the first embodiment, the thickness of the layer A is set to 12.0 μm, and the amount of particles is adjusted to adjust the roughness. The thickness of the C layer was set to 1.0 μm, and the thickness of the layer B was adjusted by changing the discharge amount, and a roll of a biaxially stretched film having a thickness of 38 μm was obtained in the same manner as in the first embodiment.

After the release layer was applied, the ceramic slurry was applied and dried, and the coated surface was slightly wavy and uneven; the pinhole was formed, and the pattern of the internal electrode was also formed. In the punching in the punching step, uneven cutting of the green sheets occurs, and as a result, the green sheets cannot be uniformly laminated, which is a poor result.

[Comparative Example 5]

In the embodiment of the first embodiment, the thickness of the layer C is 3.0 μm, and the amount of particles is adjusted to adjust the roughness. The thickness of the layer A was set to 6.5 μm, and the thickness of the layer B was adjusted by changing the discharge amount, and a roll of a biaxially stretched film having a thickness of 38 μm was obtained in the same manner as in the first embodiment.

After the release layer was applied, the ceramic slurry was applied and dried, and the applied state was good, and there was no pinhole, and the pattern of the internal electrode was also formed well. The green sheet can be cut well, but the green sheet cannot be uniformly layered, which is a poor result.

[Comparative Example 6]

In the embodiment of the first embodiment, the thickness of the layer C is set to 0.3 μm, and the amount of particles is adjusted to adjust the roughness. The thickness of the layer A was set to 6.5 μm, and the thickness of the layer B was adjusted by changing the discharge amount, and a roll of a biaxially stretched film having a thickness of 38 μm was obtained in the same manner as in the first embodiment.

After the release layer was applied, the ceramic slurry was applied and dried, and the applied state was good, and there was no pinhole, and the pattern of the internal electrode was also formed well. The green sheet can be cut well, but the green sheet cannot be uniformly layered, which is a poor result.

[Comparative Example 7]

In the embodiment of the first embodiment, the particles added to the layer C are inorganic particles, and a roll of a biaxially stretched film having a thickness of 38 μm is obtained. After the release layer was applied, the ceramic slurry was applied and dried, and the applied state was good, and there was no pinhole, and the pattern of the internal electrode was also formed well. The green sheet can be cut well, but the green sheet cannot be uniformly layered, which is a poor result.

[Comparative Example 8]

In the embodiment of the first embodiment, the main pellet of the particles added to the layer A was used as the polyester G to obtain a roll of a biaxially stretched film having a thickness of 38 μm. Pinholes are generated when the ceramic slurry is applied and irregularities are formed at the coated end. When the green sheet is punched, the curved surface of the upper surface of the green sheet is wavy. Moreover, a large amount of air entrapment occurs when the green sheets are laminated.

[Comparative Example 9]

In the embodiment of the first embodiment, a pellet of a biaxially stretched film having a thickness of 38 μm was obtained by using the main pellet of the particles added to the layer C as the polyester G. As a result of confirming the green sheet coated with the ceramic slurry and being wound up, a large number of pits were confirmed on the surface of the green sheet, and thus the internal electrode pattern was partially missing. When the green sheet is punched, the curved surface of the upper surface of the green sheet is wavy. Moreover, a large amount of air entrapment occurs when the green sheets are laminated.

[Comparative Example 10]

In the embodiment of the first embodiment, the main pellet of the particles added to the layer C is polyester E, and a roll of a biaxially stretched film having a thickness of 38 μm is obtained in an amount exceeding the lower limit of the present invention. The slurry coating and the formation of the pattern of the internal electrodes were good, but the cutting of the green sheets occurred unevenly during the punching and the green sheets were peeled off. The occurrence of a green sheet that cannot be uniformly layered is a poor result.

[Comparative Example 11]

In the embodiment of the first embodiment, the layer C was used to recover the raw material B, and a roll of a biaxially stretched film having a thickness of 38 μm was obtained. The peaks in the particle size distribution curve of the particles contained in the C layer are three. When the green sheet after the slurry coating was taken up, the minute pits were extremely conspicuous, and the corrugated irregularities were observed on the cut surface of the upper surface of the green sheet when the green sheets were punched. When a green sheet is laminated, a large amount of gas is caught, and a part of the peeling failure occurs.

[Comparative Example 12]

In order to obtain polyester E, 40% by weight of divinylbenzene (crosslinking component), 15% by weight of ethylvinylbenzene, and 45% by weight of benzene are obtained by seeding method. A water slurry having a volume average particle diameter of 0.8 μm of ethylene, a volume form factor of f = 0.51, a Mohs hardness of 3, and a copolymer of ethylene styrene/styrene (crosslinking degree of 40%), using a ventilated biaxial mixture The mixer is blended into the above homogenous polyester pellets which are substantially free of particles.

In the embodiment of the fourteenth embodiment, the polyester D and the polyester F were used to obtain a roll of a biaxially stretched film. When the green sheet was punched, the cut surface on the green sheet was slightly visibly embossed and evaluated as B. When the green sheet was laminated, peeling failure occurred and it was rated as C.

[Industrial availability]

The present invention relates to a base film for mold release based on a biaxially stretched polyester film, in particular, when a green sheet constituting a ceramic capacitor is formed into a film, the coating property of the ceramic slurry at the time of forming the green sheet of the film, The green sheet has good punching properties and green sheet build-up characteristics.

Claims (10)

A biaxially oriented polyester film for demolding comprising a three-layer polyethylene terephthalate film characterized by having a surface layer (layer A), an intermediate layer (layer B), and a surface layer (layer C), wherein The layer A contains inorganic particles and/or organic particles having a volume average particle diameter (dA) of 0.1 μm or more and 1.0 μm or less and a Mohs hardness of 7 or less with respect to the weight of the layer A of 0.05% by weight or more and 1.0% by weight or less. a layer having a thickness of 3.0 μm or more and 8.0 μm or less; and a layer B containing inorganic particles and/or organic particles having a volume average particle diameter (dB) of 0.3 μm or more and 1.5 μm or less and a Mohs hardness of 7 or less. The inorganic particles having a Mohs hardness of 7 or less and having a Mohs hardness of 7 or less and a weight of the B layer of 7 or less, and an organic particle having a Mohs hardness of 7 or less and a content of 7 or less by weight or less based on the weight of the B layer are 7 or less. a layer having a thickness of 10.0 μm or more and 35.0 μm or less; and a layer C containing a volume average particle diameter (dC) of 0.03 wt% or more and less than 1.0 wt% with respect to the weight of the layer C of 0.2 μm or more and 1.0 μm or less. Organic particles having one or two peaks in the distribution curve, and having a thickness of 0.5 μm or more and 2.0 μm or less The volume average particle diameter of the particles contained in the A layer, the B layer, and the C layer is in the relationship of the formula (1), and the thickness of the entire layer is 20 μm or more and 40 μm or less; dA<dC≦dB... ). The biaxially oriented polyester film for demolding of claim 1, wherein the organic particles contained in the A layer, the B layer, and the C layer are selected from the group consisting of crosslinked polystyrene resin particles, crosslinked oxirane resin particles, and crosslinked One type of acrylic resin particles, crosslinked styrene-acrylic resin particles, and crosslinked polyester particles; the A layer, The inorganic particles contained in the layer B having a Mohs hardness of 7 or less are selected from the group consisting of spherical cerium oxide and aluminum silicate. The biaxially oriented polyester film for mold release according to claim 1 or 2, wherein the center line roughness SRa (A) of the surface of the layer A is 3 nm or more and 10 nm or less, and the center line roughness SRa (C) of the surface of the layer C is 10 nm. Above 30 nm. The biaxially oriented polyester film for mold release according to claim 1 or 2, wherein the B layer contains the biaxially stretched generated chips generated in the polyester film production step as a recovery raw material. The biaxially oriented polyester film for demolding of claim 1 or 2 is used for the support of green sheet forming in the step of manufacturing a laminated ceramic capacitor. A biaxially oriented polyester film for demolding comprising a three-layer polyethylene terephthalate film characterized by a surface layer (A' layer), an intermediate layer (B' layer), and a surface layer (C' layer) Wherein: the center line roughness SRa (A') of the surface of the A' layer is 3 nm or more and 10 nm or less, and the center line roughness SRa (C') of the surface of the C' layer is 10 nm or more and 30 nm or less; The B' layer is a layer containing particles, and the particles contained in the A' layer and the B' layer are inorganic particles and/or organic particles having a Mohs hardness of 7 or less, and/or organic groups having a degree of crosslinking of 50 to 85%. Particles; the C' layer is a layer containing particles; the particles contained in the C' layer are particles having one or two peaks in a particle size distribution curve. The biaxially oriented polyester film for mold release according to claim 6, wherein the A' layer has a thickness of 3.0 μm or more and 8.0 μm or less, and the particles contained in the A' layer have a volume average particle diameter (dA') of 0.1 μm or more. 1.0μm or less, and relative to the A' layer The weight is 0.05% by weight or more and 1.0% by weight or less; the thickness of the B' layer is 10.0 μm or more and 35.0 μm or less, and the particles contained in the B' layer have a volume average particle diameter (dB') of 0.2 μm or more and 1.5 μm or less. The inorganic particles are contained in an amount of 0.6 to 6% by weight based on the weight of the B' layer, and the organic particles are contained in an amount of 0.05% by weight to 5% by weight based on the weight of the B' layer; and the thickness of the C' layer is 0.5 μm or more and 2.0 μm or less. The particles contained in the C' layer have a volume average particle diameter (dC') of 0.2 μm or more and 1.0 μm or less, and 0.03 wt% or more and less than 1.0 wt% with respect to the weight of the C' layer; A' layer, B' layer The volume average particle diameter of the particles contained in the C' layer is in the relationship of the formula (1'), and the thickness of the entire layer is 20 μm or more and 40 μm or less; dA < dC ≦ dB (1'). The biaxially oriented polyester film for mold release according to claim 6 or 7, wherein the organic particles contained in the A' layer and the B' layer are selected from the group consisting of crosslinked polystyrene resin particles, crosslinked oxirane resin particles, and One type of organic particles of the cross-linked acrylic resin particles, the cross-linked styrene-acrylic resin particles, and the crosslinked polyester particles; and the inorganic particles contained in the A' layer and the B' layer are selected from the group consisting of spherical cerium oxide and aluminum silicate 1 kind of inorganic particles. The biaxially oriented polyester film for demolding of claim 6 or 7, wherein the B' layer comprises a biaxially stretched generated crumb produced in the polyester film production step as a recovery material. The biaxially oriented polyester film for demolding of claim 6 or 7 is used for the support of green sheet forming in the step of manufacturing a laminated ceramic capacitor.