TWI501871B - Mold-releasable polyester film - Google Patents

Description

Release polyester film

The present invention relates to a release polyester film, and more particularly to a release film polyester film which is suitable as a carrier film used in a lamination step in a process of a printed circuit board.

If a printed circuit board having a plurality of conductor circuits is to be formed, for example, a conductor circuit having a plurality of via holes formed therein and an epoxy resin or the like impregnated in a glass cloth can be used. The carcass is layered to insulate it, insulate it, and protect the conductor.

In the process of the printed circuit board having the laminated structure, a method of integrating the laminated body by a continuous step including a heating vacuum pressing step and a high-pressure heating pressing step is generally used. At this time, the laminated body and the substrate obtained by the laminated body can be transported via a carrier film having a release property. The release film of the release film is used in such a manner that a plurality of laminated bodies for constituting a printed circuit board are inserted from above and below, and after being subjected to a heating vacuum pressing step and a high pressure heating pressing step, it is possible to The integrated printed circuit board is peeled off and wound up.

In the pressing step of manufacturing a printed circuit board, the carrier film can prevent the laminate from being in close contact with the press plate of the pressing device. However, since the epoxy resin or the like which is softened in the heating and pressing step in the laminate passes through the via hole in which the conductor circuit has been formed, it is in contact with the carrier film, and the release property of the carrier film with respect to the laminate constituting the printed circuit board is When it is bad, it causes a significant deterioration in workability, and the yield is lowered. Therefore, for the carrier film used in the lamination step of the printed circuit board, in addition to the release property between the material of the printed circuit board or the press plate of the press device, it is also required to contribute to the laminate. Uniform formability. Therefore, the carrier film is generally a polyester film having high heat resistance or dimensional stability. However, there is currently a high level of releasability requirements.

From this point of view, the polyester film proposed in JP 2002-252458 A is an amorphous yttrium oxide having a large particle diameter and having a center line thickness of 0.1 to 1.0 μm on the surface of the film and a heat shrinkage ratio of 3% or less. However, as in the embodiment of JP2002-252458A, although the large-diameter amorphous yttrium having a particle diameter of 4.5 μm or more is blended, the degree of surface roughness can be increased, but when the film contains such a particle diameter exceeding When the inorganic particles are 4.5 μm, the inorganic particles are secondarily aggregated at the time of film formation, and it is easy to form coarse particles. Therefore, in order to form a film, the pressure increase rate of the filter of the melt extruder of the melt-extruded resin is remarkably high, and the workability is further deteriorated. Although a coarse filter having an absolute filter diameter of more than 30 μm is used, the pressure increase rate can be eliminated, but the secondary coacervate is mixed into the film to cause a problem in the appearance of the film.

The polyester film proposed in JP2005-111798A is provided with a release layer formed of a polyfluorene resin or the like in a film having a center line thickness of 0.1 to 1.0 μm in order to improve the mold release property of the carrier film. However, at this time, it is necessary to add a step of forming a release layer after the process of the polyester film. Therefore, not only the cost is increased, but also the release film which is peeled off from the printed circuit board by the pressing step of the printed circuit board, and the release film formed by the polyoxyxylene resin or the like is formed in addition to the polyester film. The release layer does not provide recycling. At the same time, in the processing step of polyoxymethylene resin or the like, a residual solvent is likely to be generated, and thus there are also environmental problems.

The polyester film proposed in JP2006-312263A is a carrier film having a laminate structure and improved releasability, and the average particle diameter of one of the outermost layer of the blended particles is 3 to 10 μm, and the blending amount of the particles is 3 Up to 30% by weight, the arithmetic mean roughness of the surface roughness of the outermost layer is from 0.30 to 1.00 μm. However, although a large particle having a particle diameter of 3 μm or more is blended in a large amount to 3 to 30% by weight, the surface roughness can be increased, but when the film is produced, the blended particles are secondarily aggregated to form coarse particles, or even if The secondary aggregation of the primary particles also causes the pressure increase rate of the filter of the melt extruder to become significantly higher, and the workability is further deteriorated. In the same manner as the above-mentioned series, in this case, as long as a coarse filter having an absolute filter diameter of more than 60 μm is used, the pressure increase rate can be eliminated, but the film appearance is caused by the inclusion of secondary aggregates or primary particles in the film. The problem.

In view of the above circumstances, an object of the present invention is to provide a polyester film which can be suitably used as a carrier film in a process of a printed circuit board and which is excellent in mold release property. The process of the printed circuit board as described herein may be, for example, an insulation formed by insulating the conductor circuit or insulating the conductor circuit with a conductor formed by impregnating the conductor circuit with an epoxy resin or the like. After the substrate is laminated into a plurality of layers and the film is carried on the layered surface area layer thus obtained, the step of heating the vacuum pressing and the high-pressure heating pressing in a continuous step to integrate the laminated body is carried out.

As a result of intensive investigation to solve such problems, the present inventors have found that a biaxially stretched laminated polyester film having a specific composition can exhibit a high degree of mold release property, and the present invention has been completed.

That is, the gist of the present invention is: a release polyester film which is composed of three layers of a polyester resin layer A/polyester resin layer B/polyester resin layer A, and which is subjected to biaxial stretching. The polyester resin layer A constituting the surface layer thereof contains 1.5 to 2.8% by mass of the inert particles having an average particle diameter of 3.0 to 4.3 μm, and the polyester resin layer B constituting the intermediate layer thereof contains no inert particles or contains 0.5% by mass or less. The inert particles, and the release polyester film satisfy the following formulas (1) to (3):

D _A ≧T _A (1)

2.8≧T _A ≧0.5 (2)

100≧T≧20 (3)

However, T _A is the thickness (μm) of the polyester resin layer A, D _A is the average particle diameter (μm) of the inert particles contained in the polyester resin layer A, and T is the thickness (μm) of the entire layer of the polyester film. .

Since the release polyester film of the present invention is subjected to biaxial stretching, it can be a film excellent in mechanical properties and dimensional stability. Since the average particle diameter of the inert particles contained in the polyester resin layer A constituting the surface layer thereof is in the range of 3.0 to 4.3 μm, and the content thereof is in the range of 1.5 to 2.8% by mass, the resin can be imparted. The peelability required for layer A. The polyester resin layer B constituting the intermediate layer is a support which occupies a high proportion in the layer thickness of the entire film, and since it is a layer containing no inert particles or containing 0.5% by mass or less of inert particles, the film can be made entirely The amount of inert particles occupied in the layer is minimized. Therefore, there is no trouble in the operation of cutting the cutting blade when the cutting is performed or when the film edge portion is cut, and good mechanical properties in which the film is not easily broken can be obtained. Since the average particle diameter of the inert particles contained in the polyester resin layer A is greater than or equal to the thickness of the polyester resin layer A, the peeling property required for the resin layer A can be imparted. Since the full thickness of the polyester film is 20 μm or more and 100 μm or less, in addition to the strength required for the polyester film, it can be strongly stretched by a carrier of various automation systems or the like.

Therefore, when the carrier film for a laminate of a printed circuit board is used as the release polyester film of the present invention, the mold release property of the laminate of the printed circuit board can be maintained at a high level, and the vacuum pressing and high pressure heating can be performed. After pressing, it can be easily released from the laminate. Therefore, the release polyester film of the present invention can highly maintain the productivity of the printed circuit board process, and thus its industrial value is very high.

Hereinafter, the present invention will be described in detail.

The polyester resin of the polyester resin layer A and the polyester resin layer B of the release polyester film of the present invention is preferably polyethylene terephthalate, polybutylene terephthalate or polypair. The polyester resin such as 1,3-propanedicarboxylate is not particularly limited. Since polyethylene terephthalate is inexpensive and excellent in elongation, it is suitable for use. Generally, the oligomer can be obtained by a transesterification reaction of dimethyl terephthalate with ethylene glycol or a direct esterification reaction of terephthalic acid with ethylene glycol, followed by melt polymerization or solid phase reaction. Polyethylene terephthalate is obtained by a polymerization method.

In the polyester resin, other components may also be copolymerized. Other components may, for example, be a dicarboxylic acid component such as isophthalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, sodium 5-sulfoisophthalate, oxalic acid, succinic acid, adipic acid, Azelaic acid, azelaic acid, dodecanoic acid, dimer acid, maleicene, maleic acid, fumaric acid, itaconic acid, citraconic acid, methyl fumaric acid, a dicarboxylic acid such as cyclohexanedicarboxylic acid; or 4-hydroxybenzoic acid; ε-caprolactone; lactic acid or the like. Meanwhile, examples of the diol component of the other copolymerization component include diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol. An ethylene oxide adduct of cyclohexanedimethanol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A or bisphenol S, and the like.

The inherent viscosity of the polyester resin of the release polyester film of the present invention is not limited, but it is preferably 0.5 dl/g or more when the film has sufficient mechanical properties.

The release polyester film of the present invention is composed of three layers of a polyester resin layer A/polyester resin layer B/polyester resin layer A. The resin layer A constituting the surface layer thereof is a layer to which moderately inert particles have been blended to exhibit mold release property. The layer B belonging to the intermediate layer is a layer in which inert particles are blended at a relatively low concentration, and is a layer having a function as a supporting layer.

The polyester resin layer A contains inert particles having an average particle diameter of 3.0 to 4.3 μm in an amount of from 1.5 to 2.3% by mass. When the average particle diameter is less than 3.0 μm, the extraction time of the air described later becomes long, so that good peelability cannot be obtained. When the average particle diameter is coarse particles exceeding 4.3 μm, the filter of the melt extruder in the melt extrusion step in the production of the polyester film (the absolute filter diameter is usually 15 to 40 μm when the polyester film is produced) The boost rate will be significantly higher and the filter replacement frequency will be increased. At the same time, in the case of coarse particles, secondary aggregates or primary particles of inert particles in the film were visually observed, and the quality of the product tends to deteriorate. Further, in the pressing step of the printed circuit board, the inert particles are detached and the printed circuit board is damaged, which may cause fatal defects. In particular, in the hot pressing step, since the softened insulating substrate is passed through the via hole formed in the conductor circuit or the adhesive is overflowed when the adhesive is used, the coarse particles are easily peeled off from the carrier film. When the content of the inert particles is less than 1.5% by mass, the air extraction time to be described later becomes long, and good peelability cannot be obtained. On the other hand, when the content thereof exceeds 2.8% by mass, the pressure increase rate of the filter of the melt extruder in the melt extrusion step in the production of the polyester film is remarkably high, and the replacement frequency of the filter is increased, and at the same time, the addition is increased. In addition to the frequency at which the film is cut at the time of the film stretching, the edge of the film is trimmed, and the wear of the cutting blade is accelerated, which causes a problem that the workability is remarkably deteriorated. In addition, the pressing step of the printed circuit board also causes the inert particles to fall off.

In the release polyester film of the present invention, since the inert particles having a large particle diameter must be blended in a large amount, the rate of pressure increase of the filter in the melt extrusion step is caused to be a big problem. Among them, since the polyester resin layer B has a function as a support layer and occupies most of the thickness of the full layer, it is necessary to have a large amount of melt extrusion. Therefore, the polyester resin layer B is a layer in which the inert particles are blended in a small amount. In detail, the polyester resin layer B must be completely free of inert particles or contained in an amount of only 0.5% by mass or less. When the content of the inert particles exceeds 0.5% by mass, the pressure increase rate of the filter is accelerated, causing a problem in production. Further, the inert particles are detached in the pressing step of the printed circuit board.

The method of containing the inert resin in the polyester resin layer B may, for example, be a method of using a masterbatch containing a predetermined amount of inert particles by polymerization or mixing, or diluting the above with a polyester resin containing no inert particles. After the masterbatch, it is subjected to a predetermined amount of inert particles. Meanwhile, as will be described later, the film side portion which is removed after the extension of the polyester film may be mixed with the virgin raw material and used. In this way, it is appropriate to reduce industrial waste.

The average particle diameter of the inert particles contained in the polyester resin layer B is not particularly limited, but is preferably 1 to 5 μm.

Since the release polyester film of the present invention is applicable as a carrier film in various automation systems, it is necessary to have high mechanical properties such as tensile strength. Therefore, it must be applied to the biaxial extension.

The release polyester film of the present invention must satisfy the relationship of the following formulas (1) to (3):

D _A ≧T _A (1)

2.8≧T _A ≧0.5 (2)

100≧T≧20 (3)

However, T _A is the thickness (μm) of the polyester resin layer A, D _A is the average particle diameter (μm) of the inert particles contained in the polyester resin layer A, and T is the thickness of the entire layer of the polyester resin film (μm) ).

When D _A < T _A , the extraction time of the air described later becomes long, and good peeling property cannot be obtained.

The thickness T _{A of the} polyester resin layer A must be 0.5 to 2.8 μm, and preferably 1.0 to 2.5 μm. When it is less than 0.5 μm, the thickness of the resin layer is too thin, and the inert particles contained in the polyester resin layer A of the surface layer are detached in the pressing step of the printed circuit board, which is fatal to the printed circuit board. The possibility of defects is very high. As described above, particularly in the hot pressing step, since the softened insulating substrate is passed through the via hole formed in the conductor circuit or the adhesive is overflowed when the adhesive is used, the coarse particles are easily peeled off from the carrier film. When the content exceeds 2.8% by mass, since the amount of extrusion of the polyester resin layer A to which the inert particles are blended is increased, the rate of increase of the filter of the melt extruder is made faster, which is not preferable.

As described above, the full thickness (T) of the polyester film must be 20 to 100 μm, and preferably 25 to 50 μm. When it is less than 20 μm, the required strength cannot be obtained. At this time, after the polyester film is peeled off from the printed circuit board and then taken up by the pressing step of the printed circuit board, the film is wrinkled due to insufficient rigidity of the polyester film, and the tension is not obtained. The possibility of rupturing the membrane is very high. In order to reduce the take-up tension for winding in response to this phenomenon, wrinkles may be transmitted to the high-pressure heated pressing portion, with the result that the quality of the product is affected and the defective rate is improved. Conversely, when the full thickness (T) of the polyester film exceeds 100 μm, it will only cause excessive quality or high cost, or lengthen the air extraction time.

The inert particles to be blended in the release polyester film of the present invention may, for example, be as follows. Examples thereof include inorganic particles such as cerium oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum oxide, zeolite, kaolin, clay, talc, and mica; or acrylic resin, polystyrene resin, phenol resin, melamine resin, Organic particles such as benzoguanamine resin, polymethyl methacrylate resin, and organic polyfluorene oxide resin. Among them, silica is suitable for use because of its excellent particle size distribution and film formability and low cost. Further, two or more kinds of inert particles may be used in combination.

When the release polyester film of the present invention is used as a carrier film for a process of a printed circuit board, the time for measuring the air extraction by the method described later is preferably 1.5 seconds or less. The air extraction time is 1.5 seconds or less, which means that the peelability is good. On the other hand, the so-called air extraction time exceeds 1.5 seconds, which means that the peeling property is bad. That is, it means that when the polyester film is peeled off from the printed circuit board after the pressing step of the printed circuit board, the film is subjected to impedance and is not easily peeled off, and the polyester film is peeled off from the printed circuit board. When the film is taken up, wrinkles are generated, so that the tendency to wind up the film and break the film is high. Meanwhile, when the air extraction time exceeds 1.5 seconds, wrinkles may propagate to the high-pressure heat-pressed portion even when the take-up tension is weakened, and the tendency of the product quality is improved to increase the defect rate.

The release polyester film of the present invention may be subjected to a known sand mat treatment or emboss processing on the surface to form irregularities on the surface of the film. Alternatively, a coating treatment may be applied to the surface of the film by using a polyoxyxylene resin, an epoxy resin or the like according to a known method.

Next, an example of a method for producing a release polyester film of the present invention will be described.

Two kinds of polyester resins which have been blended with a predetermined amount of inert particles are respectively supplied to respective extruders, and then melted at a temperature from the melting point of each polyester resin to (melting point + 40 ° C), which is to be made of stainless steel fibers. The formed web is sintered and compression-molded to form a filter having an absolute filter diameter of 20 to 30 μm, which is respectively merged into a multimanifold die or a feed block via the filter, by a T-die ( T die) is extruded into a laminate of three layers of a polyester resin layer A/polyester resin layer B/polyester resin layer A. Then, a squeezed laminated sheet-like body is adhered to a cooling drum whose temperature has been adjusted to 30 ° C or less by a well-known method such as static voltage casting or air knife, and is quenched and solidified until After the temperature below the glass transition temperature, a laminated unstretched sheet of the desired thickness is obtained. Then, the obtained laminate unstretched sheet is biaxially stretched in the longitudinal direction and the transverse direction to obtain a release polyester film excellent in mechanical properties and dimensional stability.

In the case of the biaxial stretching method, a method such as a simultaneous biaxial stretching method in which a tenter type simultaneous simultaneous biaxial machine is extended in the longitudinal direction and the lateral direction, or a longitudinal extension by a roller type stretching machine can be used. Thereafter, a two-axis extending method in which the tenter type transverse stretcher extends in the lateral direction is used. However, when the sequential two-axis stretching method is used, even if the same area magnification is extended with the simultaneous two-axis stretching method, since the air extraction time becomes longer, the simultaneous two-axis stretching method is applicable.

The stretching ratio is preferably such that the area ratio of the polyester film is 3 times or more, more preferably 4 to 25 times, and still more preferably 6 to 20 times. When the area magnification is less than 3 times, it is difficult to obtain a film having a low air extraction time.

The stretching temperature is preferably in the range of the glass transition temperature of the polyester resin to (glass transition temperature + 60 ° C). The relaxation rate of the stretched film in the longitudinal direction and the transverse direction is 0 to 10%, and heat treatment is performed in a tenter at a temperature of 150 ° C to (melting point of the polyester - 5 ° C) for several seconds, and then cooled to room temperature. Take up at a speed of 20 to 200 m/min. Thereby, a film of the desired thickness can be obtained.

The heat treatment after the above extension is a necessary step for reducing the heat shrinkage of the film. As a method of heat treatment, a method of blowing hot air, a method of irradiating infrared rays, a method of irradiating microwaves, or the like can be used. Among them, a method of blowing hot air is preferred because it can be heated uniformly and accurately.

In the manufacture of the biaxially stretched film, although the film edge portion sandwiched by the clip in the tenter is cut after the stretching process, the cut portion may not be discarded, and the input is being used as the resin layer. The polyester resin of A or / and resin layer B is melted in an extruder for recycling.

In the method of building up a laminate in which a plurality of conductor layers and an insulating layer are integrated in order to form a printed circuit board, the release polyester film of the present invention can be used as an excellent mold release property. Carrying film. The stacking method in which a plurality of conductor layers of a printed circuit board are integrated with an insulating layer is exemplified by a conductor formed of a copper foil and a body formed by impregnating a glass cloth with an epoxy resin or the like. a method of laminating by heating and pressing; a method of laminating and laminating a copper foil with a resin such as an epoxy resin or a polyimide, and an insulating layer of a resin liquid such as an epoxy resin or a polyimide. A method in which a resin body is plated with copper to form a ruthenium body, and the ruthenium body is heated and pressurized to be laminated. The release polyester film of the present invention can also be used as a carrier film of any one of the methods.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples. However, the invention is not limited to the scope of the embodiments. Meanwhile, in the following examples and comparative examples, the physical property values of the polyester film were measured as follows.

(1) Thickness of each layer

After observing the cross section of the film by an electron microscope (SEM), the thickness of each layer was measured.

(2) Particle size of inorganic particles and organic particles

It was measured by a laser diffraction scattering particle size analyzer SALD-2000 manufactured by Shimadzu Corporation.

(3) Air extraction time (peelability of film)

It was measured using the apparatus shown in Fig. 1. That is, a circular glass plate 2 is mounted on the central portion of the platform 1. On the platform 1, along the outer edge of the glass sheet 2, the air groove 8 and the air hole 9 are formed in a state of being in communication with each other. Then, the air hole 9 is connected to the vacuum pump 5 with the hose 3 to which the stopcock 4 is attached. The sample film 6 is fixed on the stage 1 with an adhesive tape 7, which is sized to cover the surface of the glass plate 2.

In the measurement, the vacuum pump 5 is driven first, and the stopcock 4 is opened to evacuate the exhaust gas in the system. At this time, the sample film 6 was adhered to the surface of the glass plate 2, and the time (seconds) at which the interference pattern began to appear from the outer edge and then spread to the entire glass plate 2 until the last stop of movement was measured, which was air extraction. time.

(4) Filter boosting speed

In the longitudinal vertical type short-axis screw (L/D=15) having a screw diameter of 14 mm in a melt extruder used, a stainless steel fiber is used on a breaker plate having a filter diameter of 10 mmφ. The resulting filter was sintered and compressed to obtain a filter having an absolute filter diameter of 20 μm (Naslon manufactured by Nippon Seisen Co., Ltd.). Then, the polyester was melt-extruded at 280 ° C at an extrusion speed of 1.0 kg / hour, and the extrusion pressure after 1 hour was measured to obtain a pressure increase rate (MPa / hour).

If the pressure increase rate exceeds 3.0 MPa/hour, the filter pressurization speed is too fast, causing problems in continuous production.

(5) Mode test of printed circuit board 1

A copper foil (400 mm × 400 mm) in which a via hole having a diameter of about 0.1 mm was formed at 5 / cm ² and a body (400 mm ×) impregnated with a glass cloth by an epoxy resin or the like was used. 400 mm), a laminate composed of copper foil/預鑄 body/copper foil/預鑄 body/copper foil was prepared. This laminated body was twisted and fixed from both sides with a pair of polyester film (450 mm × 450 mm), and then placed in an aluminum press (420 mm × 420 mm) and introduced into a hydraulic press. Next, the temperature of the hydraulic device was set to 105 ° C and the press treatment was performed at a pressure of 2.5 MPa for 10 minutes. Thereafter, the sample was taken out from the hydraulic press, and after cooling, the aluminum plate was taken out, and the polyester film was peeled off.

At this time, if the peel strength is less than 0.1 N/cm, it is evaluated as ○ because it is easily peeled off; Δ is determined when the peel strength is 0.1 to 0.3 N/cm; and when the peel strength exceeds 0.3 N/cm, due to the laminated board When the polyester film was peeled off, it was subjected to an impedance and was not easily peeled off, and it was evaluated as ×.

(6) Mode test of printed circuit board 2

Using the sample in the mode test 1 of the printed circuit board different from the above (5), the same pressing treatment as in the mode test 1 of the printed circuit board of (5) was carried out for 10 minutes. Thereafter, the edge portion of the polyester film was stretched at 10 N/cm while the hydraulic pressing was released. At this time, as long as the film is not broken and can be released, it is evaluated as ○; and as long as the film is broken, it is evaluated as ×.

(7) shedding particles

The surface of the laminated board obtained by the mode test 1 of the printed circuit board was observed under a microscope, and the number of inorganic particles adhered to the surface of the laminated board per square centimeter was measured at 10 points. When it is confirmed that the number of points of the attached inorganic particles (that is, the inorganic particles are detached from the film) is 1 or less, it is ○, and when it is confirmed that there are two or more points, it is ×.

(8) Production of film

The continuous production of the biaxially stretched polyester film was carried out for one week, and the problems during this period were extracted.

The method for producing the polyester resin used in the examples and the comparative examples will be described.

(Manufacture of polyester resin 1)

100 parts by mass of terephthalic acid and 52 parts by mass of ethylene glycol were placed in an esterification reaction tank, and esterification reaction was carried out at 260 ° C under a pressure of 0.3 MPaG. Next, the obtained polyester low polymer was supplied to a polycondensation reaction tank, and a polycondensation reaction was carried out at 280 ° C for 120 minutes to obtain a polyester resin 1 having an ultimate viscosity of 0.62. Since the obtained filter pressure of the polyester resin 1 was 0 MPa/hr, there was no increase in pressure at all.

(Manufacture of Polyester Resin 2-1)

100 parts by mass of terephthalic acid and 52 parts by mass of ethylene glycol were placed in an esterification reaction tank, and esterification reaction was carried out at 260 ° C under a pressure of 0.3 MPaG. Next, the obtained polyester low polymer is supplied to a polycondensation reaction tank. Then, an ethylene glycol dispersion (concentration: 5.5% by mass) of cerium oxide (Sylysia 550 manufactured by Fuji Silysia Co., Ltd.) having an average particle diameter of 3.9 μm filtered through a filter having a mesh diameter of 30 μm was added to the polyester low polymer in the polycondensation reaction tank. The content of cerium oxide in the produced polyester was 2.0% by mass. Thereafter, the polycondensation reaction was carried out at 280 ° C for 120 minutes to obtain a polyester resin 2 having an ultimate viscosity of 0.60. The pressure increase rate of the obtained polyester resin 2 was 1.5 MPa / hr.

(Manufacture of polyester resin 2-2)

According to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 2-2 containing 2.5% by mass of cerium oxide having an average particle diameter of 3.9 μm and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 2-2 was 1.8 MPa / hr.

(Manufacture of polyester resin 2-3)

According to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 2-3 containing 1.7 mass% of cerium oxide having an average particle diameter of 3.9 μm and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 2-3 was 1.2 MPa / hr.

(Manufacture of polyester resin 2-4)

According to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 2-4 containing 3.0% by mass of cerium oxide having an average particle diameter of 3.9 μm and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 2-4 was 3.2 MPa / hr.

(Manufacture of polyester resin 2-5)

According to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 2-5 containing 0.8% by mass of cerium oxide having an average particle diameter of 3.9 μm and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 2-5 was 0.6 MPa/hr.

(Manufacture of polyester resin 2-6)

According to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 2-6 containing 0.3 mass% of cerium oxide having an average particle diameter of 3.9 μm and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 2-6 was 0.2 MPa / hr.

(Manufacture of polyester resin 2-7)

According to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 2-7 containing 0.7 mass% of cerium oxide having an average particle diameter of 3.9 μm and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 2-7 was 0.5 MPa/hr.

(Manufacture of polyester resin 3)

Cerium oxide (Sylysia 420, manufactured by Fuji Silysia Co., Ltd.) having an average particle diameter of 3.1 μm was used. In addition, according to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 3 containing 2.0% by mass of cerium oxide and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 3 was 1.1 MPa/hr.

(Manufacture of Polyester Resin 4)

Cerium oxide (Sylysia 440, manufactured by Fuji Silysia Co., Ltd.) having an average particle diameter of 6.2 μm was used. In addition, according to the same formulation as in the production of the polyester resin 2-1, a polyester resin 4 containing 2.0% by mass of cerium oxide and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 4 was 3.8 MPa / hr.

(Manufacture of Polyester Resin 5)

Cerium oxide (Sylysia 740, manufactured by Fuji Silysia Co., Ltd.) having an average particle diameter of 5.0 μm was used. In addition, according to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 5 containing 2.0% by mass of cerium oxide and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 5 was 3.4 MPa / hr.

(Manufacture of polyester resin 6)

Cerium oxide (Sylysia 310P, manufactured by Fuji Silysia Co., Ltd.) having an average particle diameter of 2.7 μm was used. In addition, according to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 6 containing 2.0% by mass of cerium oxide and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 6 was 1.0 MPa/hr.

(Manufacture of Polyester Resin 7)

A zeolite having an average particle diameter of 4.0 μm (JC-40 manufactured by Mizusawa Chemical Co., Ltd.) was used in place of cerium oxide. In addition, according to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 7 containing 2.0% by mass of zeolite and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 7 was 1.2 MPa / hr.

(Manufacture of Polyester Resin 8)

Cerium oxide (Mizukasil P-754C, manufactured by Mizusawa Chemical Co., Ltd.) having an average particle diameter of 4.7 μm was used. In addition, according to the same formulation as in the case of producing the polyester resin 2-1, a polyester resin 8 containing 2.0% by mass of cerium oxide having an average particle diameter of 4.7 μm and an ultimate viscosity of 0.60 was obtained. The pressure increase rate of the obtained polyester resin 8 was 3.3 MPa / hr.

The examples and comparative examples will be described in detail below.

(Example 1)

The above-mentioned polyester resin 2-1 which was dried at 150 ° C dew point (dew point: -41 ° C) to a moisture content of 20 ppm was put into an extruder A (thread diameter: 150 mm), and passed through absolute filtration. The filter was 20 μm in diameter and melt extruded at 280 °C. On the other hand, the above-mentioned polyester resin 1 which was dried by dehumidifying air (dew point: -41 ° C) at 150 ° C for 5 hours to have a moisture content of 20 ppm was put into an extruder B (thread diameter: 220 mm), and an extruder. A was similarly melt-extruded at 280 ° C through a filter having an absolute filter diameter of 20 μm. The two kinds of resin which have been melted are laminated in a multi-manifold mold, and the polyester resin 2-1 is used as the resin layer A and the polyester resin 1 as the resin layer B, and the three layers of A/B/A are formed. It was extruded into a sheet shape from a T die at a total extrusion amount of 900 kg/hr. Then, it was allowed to adhere to a cooling drum having a surface temperature of 25 ° C by external static pressure casting to obtain an end-stretched sheet of A/B/A = 20/210/20 (μm).

The unstretched sheet obtained above was subjected to simultaneous biaxial stretching at an extension temperature of 92 ° C using a tenter type simultaneous biaxial stretching machine under conditions of 3 times in the longitudinal direction and 3.3 times in the transverse direction. Thereafter, the film was heat-treated at a temperature of 240 ° C for 5 seconds, and then the transverse relaxation rate was made 5% at 240 ° C, and then cooled at 80 ° C. Then, in order to remove the nip portion which was caught by the clip at both ends in the width direction of the film, the cutting was performed by a cutter of MBW50K (blade thickness: 0.25 mm) manufactured by Olfa Co., Ltd. After the mass%) was taken up by a coiler, a three-layer film having a thickness of 25.0 μm was obtained. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm).

The properties of the obtained film are shown in Table 1.

(Example 2)

The resin layer A is a polyester resin 3. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Example 3)

The thickness of the unstretched sheet was made A/B/A = 27/190/27 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 24.4 μm was obtained. The obtained film was A/B/A = 2.7 / 19.0 / 2.7 (μm). The properties of the film are shown in Table 1.

(Example 4)

For the resin layer A, a polyester resin 2-2 was used. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Example 5)

The resin layer A is a polyester resin 2-3. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Example 6)

The thickness of the unstretched sheet was made A/B/A = 20/360/20 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 40.0 μm was obtained. The obtained film was A/B/A = 2.0/36.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Example 7)

The resin layer A is a polyester resin 7. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Example 8)

The resin layer A was made of polyester resin 3, and the thickness of the unstretched sheet was made into A/B/A=27/210/27 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 26.4 μm was obtained. The obtained film was A/B/A = 2.7/21.0 / 2.7 (μm). The properties of the film are shown in Table 1.

(Example 9)

The thickness of the unstretched sheet was made A/B/A = 7/230/7 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 24.4 μm was obtained. The obtained film was A/B/A = 0.7/23.0 / 0.7 (μm). The properties of the film are shown in Table 1.

(Embodiment 10)

The thickness of the unstretched sheet was made A/B/A = 20/170/20 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 21.0 μm was obtained. The obtained film was A/B/A = 2.0/17.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Example 11)

The thickness of the unstretched sheet was made A/B/A = 20/900/20 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 94.0 μm was obtained. The obtained film was A/B/A = 2.0/90.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Embodiment 12)

The resin layer B was a polyester resin 2-6. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Example 13)

The both ends of the film in the width direction of the cut-off film of Example 1 were pulverized into flakes, and then regenerated particles (cerium oxide) which were granulated to a diameter of about 10 mm and a length of about 20 to 50 mm were prepared. The content was 0.38 mass%, and the cerium oxide particle diameter was 3.9 μm). This regenerated granules were placed in an extruder B, and the regenerated granules were adjusted to 115 kg/hr within a crushing amount of 145 kg/hr. In the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm having a concentration of 0.3% by mass in the resin layer B was obtained.

The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Example 14)

The unstretched sheet of A/B/A=20/210/20 (μm) obtained in the same formulation as in Example 1 was extended 3.0 times in the longitudinal direction at 95 ° C in a roll spreader at 120 ° C. The tenter type lateral stretcher extends 3.3 times laterally. Thereafter, the film was heat-treated at a temperature of 240 ° C for 5 seconds, and further relaxed at a temperature of 240 ° C to 5%, and then cooled at 80 ° C and then wound up to obtain a three-layer film having a thickness of 25.0 μm. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1.

(Comparative Example 1)

The resin layer A is a polyester resin 4. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained.

Although the film can be obtained in this manner, since the average particle diameter of the cerium oxide is too large, the filter pressurizing speed of the extruder A becomes too high, and there is a problem in production. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1. In the process of the printed circuit board, it was confirmed that the cerium oxide particles were detached.

(Comparative Example 2)

The resin layer A is a polyester resin 5. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained.

Although the film can be obtained in this manner, since the average particle diameter of the cerium oxide is too large, the filter pressurizing speed of the extruder A becomes too high, and there is a problem in production. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1. In the process of the printed circuit board, it was confirmed that the cerium oxide particles were detached.

(Comparative Example 3)

The resin layer A is a polyester resin 8. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained.

Although the film can be obtained in this manner, since the average particle diameter of the cerium oxide is too large, the filter pressurizing speed of the extruder A becomes too high, and there is a problem in production. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1. In the process of the printed circuit board, it was confirmed that the cerium oxide particles were detached.

(Comparative Example 4)

The resin layer A is a polyester resin 6. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1. Since the average particle diameter of the particles contained in the resin layer A is too small, the air extraction speed is slowed. Therefore, in the process of manufacturing a printed circuit board, it is difficult to peel off when the film is to be peeled off from the laminate.

(Comparative Example 5)

The thickness of the unstretched sheet was made A/B/A = 3/240/3 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 24.6 μm was obtained. The obtained film was A/B/A = 0.3/24.0 / 0.3 (μm). The properties of the film are shown in Table 1. Since the resin layer A was too thin, it was confirmed that the cerium oxide particles were detached in the process of the printed circuit board.

(Comparative Example 6)

The thickness of the unstretched sheet was made A/B/A = 50/150/50 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained.

Although the film can be obtained in this manner, the filter pressurization speed of the extruder A becomes too high, and there is a problem in production. The obtained film was A/B/A = 5.0/15.0 / 5.0 (μm). The properties of the film are shown in Table 1. Since the thickness of the resin layer A is thicker than the average particle diameter of the particles contained in the resin layer A, the air extraction time is elongated. Therefore, in the process of manufacturing a printed circuit board, it is difficult to peel off when peeling off a film from a laminated board.

(Comparative Example 7)

The thickness of the unstretched sheet was made A/B/A = 30/200/30 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 26.0 μm was obtained.

Although the film can be obtained in this manner, the filter pressurization speed of the extruder A becomes too high, and there is a problem in production. The obtained film was A/B/A = 3.0/20.0 / 3.0 (μm). The properties of the film are shown in Table 1.

(Comparative Example 8)

The thickness of the unstretched sheet was made A/B/A = 20/120/20 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 16.0 μm was obtained. The obtained film was A/B/A = 2.0/12.0/2.0 (μm). The properties of the film are shown in Table 1. Since the full thickness of the film is too thin, after the printed circuit board is manufactured, the film is broken when the film is stretched. Therefore, in the continuous process of the printed circuit board, when the release film is taken up, there is a possibility that the film is broken or wrinkles are generated, which is a lack of practicality.

(Comparative Example 9)

The resin layer A is a polyester resin 2-4. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. However, since the content of cerium oxide in the resin layer A is too large, although the film can be obtained, the filter pressurization speed of the extruder A is made too high. Therefore, there are production problems. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1. In the process of the printed circuit board, it was confirmed that the cerium oxide particles were detached.

(Comparative Example 10)

The resin layer A is a polyester resin 2-5. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1. Since the content of cerium oxide in the resin layer A is too small and the air extraction time is elongated, it is difficult to peel off when the film is to be peeled off from the laminate in the process of the printed circuit board.

(Comparative Example 11)

The resin layer A was made of a polyester resin 6, and the thickness of the unstretched sheet was made into A/B/A = 28/210/28 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 26.6 μm was obtained. The obtained film was A/B/A = 2.8 / 21.0 / 2.8 (μm). The properties of the film are shown in Table 1. Since the thickness of the resin layer A is thicker than the average particle diameter of the particles contained in the resin layer A, the air extraction time is elongated. Therefore, in the process of manufacturing a printed circuit board, it is difficult to peel off when peeling off a film from a laminated board.

(Comparative Example 12)

The thickness of the unstretched sheet was made A/B/A = 20/1,000/20 (μm). Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 104.0 μm was obtained. The obtained film was A/B/A = 2.0/100.0 / 2.0 (μm). The properties of the film are shown in Table 1. Since the resin layer B is too thick, the air extraction time is elongated. Therefore, in the process of manufacturing a printed circuit board, it is difficult to peel off when peeling off a film from a laminated board.

(Comparative Example 13)

The resin layer B is a polyester resin 2-8. Otherwise, in the same manner as in Example 1, a three-layer film having a thickness of 25.0 μm was obtained. However, since the content of yttrium oxide in the resin layer B is excessive, although the film can be obtained, the filter pressurization speed of the extruder B is made too high. Therefore, there are production problems. The obtained film was A/B/A = 2.0/21.0 / 2.0 (μm). The properties of the film are shown in Table 1. Since the content of cerium oxide in the resin layer B was too large, it was confirmed that the cerium oxide particles were detached in the process of the printed circuit board.

As shown in Table 1, the films of Examples 1 to 4 were polyester films excellent in mold release property.

In contrast, in each comparative example, there are the following problems.

In Comparative Examples 1 to 3, since the average particle diameter of cerium oxide in the resin layer A exceeded the range defined by the present invention, it was confirmed that cerium oxide particles were detached in the process of the printed circuit board.

With respect to Comparative Example 4, since the average particle diameter of cerium oxide in the resin layer A did not reach the range specified by the present invention, the air extraction time was elongated. Therefore, in the process of manufacturing a printed circuit board, since the film has poor mold release property, it is difficult to peel off when peeling off the film from the laminated board, and the film is broken.

In Comparative Example 5, since the thickness of the resin layer A was too thin to exceed the range of the formula (2), it was confirmed that the cerium oxide particles were detached in the process of the printed circuit board.

With respect to Comparative Examples 6 and 7, the thickness of the resin layer A was too thick beyond the range of the formula (2). Therefore, the filter pressurization speed of the extruder of the resin layer A which has been blended with the inert particles becomes faster, and there is a problem in production.

With respect to Comparative Example 8, since the full thickness of the film was too thin to exceed the range of the formula (3), the film was broken in the process of the printed circuit board.

With respect to Comparative Example 9, since the cerium oxide content in the resin layer A exceeds the range specified by the present invention, the filter pressurization speed of the extruder of the resin layer A which has been blended with the inert particles becomes faster, and there is production. problem. At the same time, in the process of the printed circuit board, it was confirmed that the cerium oxide particles were detached.

With respect to Comparative Example 10, since the cerium oxide content in the resin layer A did not reach the range specified in the present invention, the air extraction time was elongated. Therefore, in the process of manufacturing a printed circuit board, since the film has poor mold release property, it is difficult to peel off when peeling off the film from the laminated board, and the film is broken.

With respect to Comparative Examples 6 and 11, the thickness of the resin layer A was thicker than the average particle diameter of the particles contained in the resin layer A, and was outside the range of the formula (1). Therefore, the air extraction time is elongated, and in the process of the printed circuit board, it is difficult to peel off when the film is to be peeled off from the laminate.

Regarding Comparative Example 12, since the full thickness of the film was too thick and was outside the range of the formula (3), the air extraction time was elongated. Therefore, in the process of manufacturing a printed circuit board, since the film has poor mold release property, it is difficult to peel off when the film is to be peeled off from the printed circuit board.

With respect to Comparative Example 13, since the cerium oxide content in the resin layer B exceeds the range specified by the present invention, the filter pressurization speed of the extruder B of the resin layer B which has been blended with the inert particles becomes faster, and there is production. The problem. At the same time, in the process of the printed circuit board, it was confirmed that the cerium oxide particles were detached.

1. . . platform

2. . . glass plate

3. . . hose

4. . . Stopcock

5. . . Vacuum pump

6. . . Sample film

7. . . Adhesive tape

8. . . Air trench

9. . . Air hole

Fig. 1 is a cross-sectional view of a device for measuring the air extraction time of a film.

Since the picture in this case is a diagram of the test method, it is not a representative figure of the case.

Therefore, there is no designated representative map in this case.

Claims (4)

A release polyester film which is composed of three layers of a polyester resin layer A/polyester resin layer B/polyester resin layer A and which is applied to a biaxially stretched one, wherein a surface layer thereof is formed. The ester resin layer A contains 1.5 to 2.8% by mass of inert particles having an average particle diameter of 3.0 to 4.3 μm, and the polyester resin layer B constituting the intermediate layer thereof contains no inert particles or contains 0.5% by mass or less of inert particles, and the mold release is also carried out. The polyester film system satisfies the following formula (1) to formula (3): D _A ≧ T _A (1) 2.8 ≧ T _A ≧ 0.5 (2) 100 ≧ T ≧ 20 (3) (however, T _A is a poly The thickness (μm) of the ester resin layer A, D _A is the average particle diameter (μm) of the inert particles contained in the polyester resin layer A, and T is the total layer thickness (μm) of the polyester film. The release polyester film of claim 1 is applied to a simultaneous biaxial extension. The release polyester film of claim 1 or 2, wherein the air extraction time is 1.5 seconds or less. A carrier film for a process for producing a printed circuit board, which comprises the release polyester film of any one of claims 1 to 3.