CN1329185C - Laminated film and method for producing same - Google Patents

Abstract

The purpose of this invention is to provide a thin film with good thermal dimensional stability, buffering properties, and low dielectric properties. Specifically, this invention is a composite film composed of at least two layers, wherein at least one layer is a biaxially oriented film made of a thermoplastic resin composition, and the other at least one layer is a film with a mesh structure.

Description

Composite film and manufacturing method thereof

technical field

The present invention relates to a composite film, for example, applicable to various industrial materials such as circuit boards, magnetic recording media, engineering paper/release materials, plate-making printing materials, optical/display materials, molding materials, construction, and electrical insulation materials. composite film.

Background technique

Films are used in various industrial materials such as magnetic recording media, circuit materials, plate making/printing materials, engineering/release materials, printing materials, molding materials, electrical insulation materials, agricultural use, packaging, building materials, etc. It has been used in various fields where there is a large demand.

However, in recent years, higher performance of thin films has been desired for various applications.

In recent years, the demand for flexible printed circuit boards (FPCs) has been rapidly increasing along with technological advancements in electronic devices such as mobile phones, and FPCs have been reduced in thickness in response to miniaturization and weight reduction of such devices. Therefore, the copper-bonding polyimide film for FPC is also being thinned or the polyimide film is thinned at the same time, but the rigidity of the film itself is reduced, making it difficult to process when manufacturing FPC. In order to simplify the handling during processing, a slightly adhesive reinforcing film that can be peeled off after processing is attached to make it rigid. As a reinforcing film, for example, a polyester film may be used. When manufacturing FPC in this way, there is a process of heat and pressure treatment, curing, or assembly of IC chips in the state where the reinforcing film is pasted, but compared with copper-bonded polyimide film, because polyester The thermal expansion coefficient of the film is large and the thermal dimensional stability is insufficient, so problems such as thermal deformation, warpage, or deterioration of planarity are caused during the manufacturing process of FPC.

In addition, in the field of electric and electronic components, polyphenylene sulfide film has the advantages of good heat resistance and small dimensional change caused by water absorption, so it is a promising material for molding substrates for circuits, but it has the problem of large thermal expansion coefficient. . Although the solution of adding glass fibers or granular inorganic fillers has been disclosed for this problem (refer to Patent Documents 1 and 2), these methods may not necessarily obtain satisfactory results, and the planarity or surface smoothness of the film, or even There are still difficulties in terms of cost.

In addition, the floor material of a building and the like may require thermal insulation cushioning properties. Polyolefin foams are well known as materials having thermal insulation and cushioning properties. However, since this material is difficult to make a thin film, it is a material that is limited to unsatisfactory materials as a thermal insulation cushioning material placed under the floor, and a material with thermal insulation cushioning properties is required as a thin film.

In addition, printing material films such as printing stamp substrates or image forming materials also require cushioning properties. For example, polyester is disclosed by mixing thermoplastic resins or inorganic particles other than polyester to stretch the film (refer to Patent Literature 3, 4, 5). However, such a film has a problem of insufficient dimensional stability against heat and insufficient flexibility.

In addition, in recent years, the demand for high-speed signal processing and digitalization for high-performance electronic equipment has been further increased, and high performance is also required for thin films used in this application. In particular, in the case of thermoplastic resin films used for printed circuit boards, cable covering insulation, and insulation of engine transformer parts, as electrical characteristics suitable for high frequency with high-speed signal processing, it is required to suppress loss during transmission. Permittivity and low dielectric loss tangent. In particular, in machines with rotating machines such as engines, precise controllable conversion control is performed for high efficiency and high functionality, which tends to cause an increase in leakage current of high-frequency components of insulating parts.

In order to impart low dielectric properties to the insulating film, there is a method of forming the pores of independent cells with a gas with a dielectric constant as low as 1. For example, there is (1) a method of forming cells by foaming a foaming agent (refer to the patent document 6), (2) The method of forming microporous cells by stretching and molding mixed incompatible resins (see Patent Document 7 and Patent Document 8), (3) Thermoplastic resins composed of two or more components are decomposed by Spinoda A method of phase separation of resins, removal of at least one or a fraction of resins by etching, thermal decomposition, alkali decomposition, etc. to form microporosity (see Patent Document 9).

However, since the thermoplastic resin film obtained by the method (1) above becomes a film with non-uniform distribution of pores, the dielectric constant may be unstable depending on the measurement location, or moldability may be impaired due to the formation of pores by the foaming agent. or heat resistance. On the other hand, in the thermoplastic resin film obtained by the method (2) above, due to the mixing of incompatible resins, the dispersion control is insufficient, resulting in the distribution of voids and sometimes impairing the molding processability. In addition, the thermoplastic resin film obtained by the above method (3) is sometimes difficult to use in practice due to the complexity of the steps in which at least one component must be removed in order to form pores.

Patent document 1: Japanese Patent Application Laid-Open No. 5-310957

Patent Document 2: Patent No. 2952923

Patent Document 3: Japanese Patent Publication No. 6-96281

Patent Document 4: Japanese Patent Application Laid-Open No. 2-29438

Patent document 5: Japanese Patent Application Laid-Open No. 6-322153

Patent Document 6: Patent No. 3115215

Patent Document 7: Japanese Patent Application Laid-Open No. 9-286867

Patent Document 8: Japanese Patent Application Laid-Open No. 11-92577

Patent Document 9: JP-A-2003-64214

Therefore, the object of the present invention is to provide a thin film with excellent thermal dimensional stability, cushioning properties and low dielectric properties.

In addition, Patent Documents 10 and 11 disclose films in which liquid crystalline polymers are dispersed in polyester. However, there is no disclosure of a network structure, cracks or voids as described later.

Patent Document 10: Japanese Unexamined Patent Publication No. 298313

Patent Document 11: Japanese Patent Application Laid-Open No. 11-5855

Contents of the invention

The present invention consists of the following constitutions.

(1) Composite film, characterized in that it is a composite film made of at least 2 layers of film, at least one layer of this composite film is a biaxially stretched film made of a thermoplastic resin composition, and at least one other layer is a reticulated film. Structured film.

(2) The composite film described in (1) above is characterized in that a biaxially stretched layer made of a thermoplastic resin is compounded on both outer surfaces of the film layer having a network structure.

(3) The composite film described in (1) or (2) above, wherein the film layer having a network structure is made of a non-ductile resin composition.

(4) The composite film according to any one of (1) to (3) above, wherein the film layer having a network structure contains a liquid crystalline polymer.

(5) The composite film described in (4) above, wherein the film layer having a network structure further contains a non-liquid crystalline polyester.

(6) The composite film described in (5) above, wherein the non-liquid crystalline polyester is polyethylene terephthalate, polyethylene naphthalate, or a modified product thereof.

(7) The composite film according to any one of (4) to (6) above, wherein the content of the liquid crystalline polymer relative to the film layer having a network structure is 20 to 90% by weight.

(8) The composite film according to any one of (4) to (7) above, wherein the content of the liquid crystal polymer is 3 to 30% by weight relative to the entire composite film.

(9) The composite film according to any one of (1)-(8) above, wherein the thickness of the film layer having a network structure is 1-90% of the total thickness of the composite film.

(10) The composite film described in (9) above, wherein the thickness of the film layer having a network structure is 10-80% of the total thickness of the composite film.

(11) The composite film described in any one of the above (1)-(10), characterized in that the thermoplastic resin composition of the biaxially stretched film layer contains a compound selected from polyester, polyphenylene sulfide, polyether At least one of imide, polycarbonate, polyetherketone, polyethersulfone, polysulfone, and polylactic acid.

(12) The composite film according to any one of the above (1)-(11), characterized in that the Young's modulus of the composite film is 2-7 GPa both in the machine direction and in the transverse direction.

(13) The composite film according to any one of the above (1)-(12), characterized in that the thermal shrinkage rate of the composite film at a temperature of 150°C is 0-2% in both longitudinal and transverse directions.

(14) The composite film according to any one of (1)-(13) above, characterized in that the composite film has a thermal expansion coefficient of 3-45 ppm/°C both in the longitudinal direction and in the transverse direction.

(Above, (1)-(14) is referred to as "composite film of the present invention of the first group")

(15) Composite film, characterized in that it is a composite film composed of at least two layers of film, at least one layer of which is a biaxially stretched film made of a thermoplastic resin composition, and at least one other layer is a non-ductile resin The composite film has a specific gravity of 0.2-1.2.

(16) The composite film described in (15) above, characterized in that a biaxially stretched layer made of a thermoplastic resin is compounded on both outer surfaces of the layer made of the non-extensible resin composition.

(17) The composite film described in (15) or (16) above, wherein the non-ductile resin composition contains a liquid crystalline polymer.

(18) The composite film described in (17) above, wherein the non-ductile resin composition further contains a non-liquid crystalline polyester.

(19) The composite film described in (18) above, wherein the non-liquid crystalline polyester is polyethylene terephthalate, polyethylene naphthalate, or a modified product thereof.

(20) The composite film according to any one of (17) to (19) above, characterized in that the content of the liquid crystalline polymer relative to the aforementioned non-ductile resin composition is 20 to 90% by weight.

(21) The composite film as described in any one of (17)-(20) above, characterized in that the content of the liquid crystal polymer is 3 to 30% by weight relative to the entire composite film.

(22) The composite film according to any one of (15)-(21) above, wherein the thickness of the layer made of the non-ductile resin composition is 1-90% of the total thickness of the composite film.

(23) The composite film described in (22) above, wherein the thickness of the layer made of the non-ductile resin composition is 10-80% of the total thickness of the composite film.

(24) The composite film described in any one of the above (15)-(23), characterized in that the thermoplastic resin composition of the biaxially stretched film layer contains a compound selected from polyester, polyphenylene sulfide, polyether imide At least one of amine, polycarbonate, polyetherketone, polyethersulfone, polysulfone, and polylactic acid.

(25) The composite film according to any one of (15)-(24) above, characterized in that the Young's modulus of the composite film is 2-7 GPa both in the machine direction and in the transverse direction.

(26) The composite film according to any one of (15)-(25) above, characterized in that the composite film has a heat shrinkage ratio of 0-2% at a temperature of 150°C in both the longitudinal and transverse directions.

(27) The composite film according to any one of (15)-(26) above, characterized in that the thermal expansion coefficients of the composite film are 3-45 ppm/°C both in the longitudinal direction and in the transverse direction.

(Above, (15)-(27) is called "composite film of the present invention of the 2nd group".)

(28) A method for producing a composite film, characterized in that it is a method for producing a composite film by co-extruding at least two layers of a resin composition, wherein at least one layer of the composite film uses a thermoplastic resin composition, and the other at least one layer Using a non-ductile resin composition, the layer using the non-ductile resin composition is cracked by biaxial stretching.

(29) The method for producing a composite film according to (28) above, wherein a thermoplastic resin composition is used for the layers on both outer sides of the layer using the non-ductile resin composition.

(30) A circuit material using the composite film described in any one of (1) to (27) above.

(31) A release material using the composite film described in any one of (1) to (27) above.

(32) An electrical insulating material using the composite film described in any one of (1) to (27) above.

By adopting the invention, a film with good thermal dimensional stability, cushioning property and low dielectric property can be prepared.

A brief description of the drawings

Figure 1 schematically shows a typical network structure observed for the networked film layer of the composite film of the present invention.

Fig. 2 represents the micrograph of the network structure observed in the layer A of the composite film prepared in Example 1.

Best way to implement the invention

The composite film of the present invention is composed of at least two layers, and at least one layer of the composite film is composed of a thermoplastic resin composition.

As the polymer constituting the thermoplastic resin composition, as long as it is a biaxially stretchable polymer, for example, polyester, polyarylate, polyphenylene sulfide, polyimide, polyetherimide, Polyamide, polyamideimide, modified polyphenylene oxide, polycarbonate, polypropylene, polyethylene, polyetherketone, polyketone, polyethersulfone, polyether, polylactic acid, etc., and copolymers thereof. In addition, a blend containing at least one of these polymers may also be used. In the present invention, from the viewpoint of biaxial stretchability and the effect of the present invention, polyester, polyphenylene sulfide, polyetherimide, polycarbonate, polyetherketone, polyethersulfone, polysulfone, and polylactic acid are preferred. Particular preference is given to polyester or polyphenylene sulfide, especially polyester.

Polyester can continuously produce large-area films that cannot be produced with other materials, and can be used in various applications by virtue of the characteristics that can impart strength, durability, transparency, flexibility, and surface properties.

The polyester is preferably a polyester having an acid component such as an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, or an aliphatic dicarboxylic acid, and a diol as main constituents.

As the aromatic dicarboxylic acid component, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, Dicarboxylic acid, benzophenone dicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, 3,3'-diphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4, 4'-diphenylsulfonedicarboxylic acid and the like, among which terephthalic acid, phthalic acid and 2,6-naphthalene dicarboxylic acid are preferable. As the alicyclic dicarboxylic acid component, for example, hexahydroterephthalic acid, 1,3-adamantanedicarboxylic acid, cyclohexanedicarboxylic acid and the like can be used. As the aliphatic dicarboxylic acid component, for example, adipic acid, succinic acid, azelaic acid, suberic acid, sebacic acid, dodecanedioic acid and the like can be used. These acid components may be used alone or in combination of two or more, and a hydroxy acid such as hydroxyethoxybenzoic acid or the like may be partially copolymerized.

In addition, as diol components, for example, chlorohydroquinone, methylhydroquinone, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenylsulfone, 4,4' -Aromatic diols such as dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, and terephthalenedimethanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, and neopentyl diol Alcohol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexane Alkanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2'-bis(4'-β-hydroxyethoxyphenyl) Among them, propane and the like, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, diethylene glycol, etc. are preferably used, and ethylene glycol is particularly preferably used. These diol components may be used alone or in combination of two or more.

In addition, polyester can be copolymerized with monofunctional compounds such as lauryl alcohol and phenyl isocyanate, and can also be used for trimellitic acid, pyromellitic acid, glycerol, pentaerythritol, 2,4-dihydroxybenzoic acid, etc. The trifunctional compound etc. are copolymerized within the range where the polymer is not branched or crosslinked but actually linear. In addition, in addition to acid components and diol components, aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid, m-hydroxybenzoic acid, and 2,6-hydroxynaphthoic acid can also be copolymerized with p-aminophenol, p-aminobenzoic acid, etc.

As the polyester, polyethylene terephthalate, polyethylene 2,6-naphthalene dicarboxylate, and their copolymers or modified polyesters are preferably used from the viewpoints of mechanical strength, production efficiency, and operability. at least one selected from the Such polyethylene terephthalate and polyethylene 2,6-naphthalene dicarboxylate contain at least 80 mol% of terephthalic acid or 2,6-naphthalene dicarboxylic acid as an acid component. A small amount of other dicarboxylic acid components may also be copolymerized as a polymer. Moreover, although it is a polymer containing 80 mol% or more of ethylene glycol as a diol component, you may add another diol component as a copolymerization component.

From the viewpoints of film-forming property, heat resistance, hydrolyzability, processing stability, dimensional stability, etc., the lower limit value of the intrinsic viscosity of polyester is preferably 0.50 dl/g or more, more preferably 0.55 dl/g or more, and more preferably 0.55 dl/g or more. Preferably it is 0.6 dl/g or more. On the other hand, the upper limit is preferably 2.0 dl/g or less, more preferably 1.4 dl/g or less, still more preferably 1.0 dl/g or less.

As polyphenylene sulfide (PPS), it is preferable to contain 80 mol% or more of phenylene sulfide components, and it is more preferable to contain 90 mol% or more. By containing 80 mol% or more of the phenylene sulfide component, PPS with high crystallinity and thermal transition temperature can be obtained, and heat resistance, dimensional stability, mechanical properties, dielectric properties, etc. characteristic of PPS can be obtained. In addition, as long as such a content of the phenylene sulfide component can be ensured, units having other thioether bonds that can be copolymerized may be contained. Examples of such units include trifunctional units such as trihalobenzene, ether units, sulfone units, ketone units, meta-bonding units, aryl units having substituents such as alkyl groups, biphenyl units, biphenyl units, and so on. Triphenylene units, vinylene units, carbonate units, etc. may be used alone or in combination of two or more. As the form of copolymerization, either random type or block type may be used.

In addition to the aforementioned characteristics of PPS, when thermal fusion properties, moisture absorption dimensional stability, etc. are desired and PPS is used as a constituent of the resin composition, it is preferable to make a composition containing 60% by weight or more of the PPS component. By making content of PPS 60 weight% or more, the characteristic of PPS can be acquired also as a resin composition. If such a content of PPS can be ensured, polymers other than PPS, inorganic or organic fillers, lubricants, colorants, and the like may be added.

In addition, the melt viscosity of the resin composition having PPS as the main component is preferably 500-50000 poise, more preferably 1000-20000 poise at 300°C and a shear rate of 2000 sec ^-1 .

It is important that the layer composed of the thermoplastic resin composition be biaxially stretched. Strength that can be used for various purposes can be obtained by biaxial stretching.

In the composite film of the present invention of the first group, it is important that at least one other layer is a film having a network structure. By forming a network structure or a structure with voids, a low dielectric constant or excellent cushioning properties can be obtained. In addition, since the rigidity as a composite film is lowered, excellent morphological stability can be obtained. In addition, thermal expansion is reduced, and excellent thermal dimensional stability can be obtained.

In this network structure, the fibril-shaped, strip-shaped, or bead-shaped linear constituent elements are connected in a network-like form within the film layer. Also, for example, a quasi-network shape in which voids are continuous in the longitudinal direction and/or lateral direction may be used on a surface parallel to the film surface. In such a network structure, the elements constituting the mesh may be bent, and the continuity of the gaps may be partially interrupted as long as the effects of the present invention are not particularly affected.

In addition, in the thickness direction of the film, either a network structure or a structure in which voids are connected is preferable.

In addition, the material forming the linear constituents may be all of the non-ductile resin composition described later, or a liquid crystal polymer contained in the non-ductile resin composition described later may also exhibit non-ductility. part of the substance.

The minor axis of the above-mentioned fibril-shaped, strip-shaped, or bead-shaped linear constituents observed by a transmission electron microscope photograph is preferably 5 nm to 100 μm, more preferably 50 nm to 10 μm, and still more preferably 0.1 μm to 5 μm. In FIG. 1 , thick lines represent linear constituents forming a network structure, and D represents the minor diameter of the linear constituents. By making the minor axis 100 μm or less, film forming properties can be maintained, waviness on the surface of the film can be suppressed, planarity of the film can be maintained, and processability of the film usable for various applications can be maintained. In addition, although the short axis may be thin, what is currently obtained is 5 nm or more.

The thin film layer having such a network structure may contain linear components having different diameters and sizes, may form many network structures with different sizes, and may form a fine network structure inside the linear components. In these cases, the diameter of the linear constituents forming a larger network structure can be controlled within the above-mentioned preferable range.

The porosity in the network structure is preferably 20-80%, more preferably 30-70%, and still more preferably 30-60%, from the viewpoint of exhibiting various effects of the present invention.

In addition, "another at least one layer" in the composite film of the present invention is also a film, and does not contain, for example, a nonwoven fabric.

The form of the above-mentioned network structure and voids is also a preferred form for the composite film of the present invention of the second group.

The above-mentioned network structure or voids can be obtained, for example, by using a non-ductile resin composition for the layer.

That is, in the composite film of the present invention of the second group, it is important that at least one other layer is composed of a non-ductile resin composition.

The non-ductile resin composition referred to in the present invention is a resin composition having an elongation at a temperature of 100° C. of 50% or less according to the “measurement method” described later in the examples. That is, it is a resin composition in which the stress-strain curve in the tensile test rises rapidly. A network structure or voids can be formed by biaxially stretching a layer composed of such a non-extensible resin composition and a layer composed of a thermoplastic resin composition.

The non-ductile resin constituting at least a part of the non-ductile resin composition is specifically preferably a resin containing a liquid crystalline polymer. Alternatively, the network-structured film layer of the composite film of the present invention in the first group preferably contains a liquid crystalline polymer.

As the liquid crystalline polymer, for example, a copolyester composed of a structural unit selected from an aromatic oxycarbonyl unit, an aromatic dioxygen unit, an aromatic dicarbonyl unit, an alkylene dioxygen unit, and the like can be used.

As a commercially available product, "Shiberas" (manufactured by Toray Co., Ltd.), "Bektora" (manufactured by Polyplastics Co., Ltd.), "Zenait" (manufactured by DuPont), "Sumilisu-Pa-1" ( Sumitomo Chemical Co., Ltd.), "Zaidaichi" (Solvay Corporation), "Ueno LCP" (Ueno Pharmaceutical Co., Ltd.), "Titan" (Eastman Corporation) and the like.

As the liquid crystalline polymer, preferable liquid crystalline polymers from the viewpoint of structural units include:

Copolyesters containing the following structural units (I), (II), (III) and (IV),

Copolyesters containing the following structural units (I), (III) and (IV),

Copolyester containing following (I), (II) and (IV) structural units,

or blends of these copolyesters.

OR ₂ -O (II)

和/或 Whereas R ₁ in the formula means

and / or

R ₂ means selected from

more than one of

R ₃ means selected from

more than one of . In addition, X in the formula represents a hydrogen atom or a chlorine atom.

In addition, in the case of a copolyester composed of the above-mentioned structural units (I), (II) and (IV), it is particularly preferred that R _is

的结构单元、R₃是

的结构单元。However, in the case of copolyesters composed of the above structural units (I), (III) and (IV), it is particularly preferred _that R is

The structural unit, R ₃ is

structural unit.

In addition, in the case of copolyesters composed of the above structural units (I), (II), (III) and (IV), it is particularly preferred _that R is

_R2 is

_R3 is

In these copolyesters, the structural unit (II) forms a repeating unit in the polymer with the structural unit (IV), and the structural unit (III) also forms a repeating unit in the polymer with the structural unit (IV). That is, in these copolyesters, the sum of the number of moles of the structural unit (II) and/or (III) is substantially equal to the number of moles of the structural unit (IV). The so-called "actually" here means that any one of the carboxyl end group or the hydroxyl end group in the polyester end group can be increased as required. In this case, strictly speaking, the number of moles of the structural unit (IV) and the structure The sum of the molar numbers of the units (II) and (III) is not equal, but such a case is also included.

In the case of a copolyester composed of the above-mentioned structural units (I), (II), (III) and (IV), the sum of the moles of the above-mentioned structural units (I), (II) relative to (I), (II) ), the fraction of the sum of moles of (III) is preferably 5-95 mol%, more preferably 30-90 mol%, and more preferably 50-80 mol%. And, the fraction of the molar number of (III) relative to the sum of the molar numbers of structural units (I), (II), (III) is preferably 5-95 mole %, more preferably 10-70 mole %, most preferably 20- 50 mol%. In addition, the molar ratio of the structural units (I)/(II) is preferably 75/25-95/5, more preferably 78/22-93/7 from the viewpoint of fluidity.

In the case of a copolyester composed of the above-mentioned structural units (I), (III) and (IV), the ratio of the number of moles of the above-mentioned structural unit (I) to the sum of the number of moles of (I) and (III) is preferably 5-95 mol%, more preferably 50-80 mol%.

In the case of a copolyester composed of the above-mentioned structural units (I), (II) and (IV), it is preferably combined with a copolyester composed of the structural units (I), (II), (III) and (IV) and/or Or a copolyester composed of structural units (I), (III) and (IV) is used for blending. In the case of such blended polymers, the ratio of the sum of the moles of the structural units (I), (II) to the sum of the moles of the structural units (I), (II), and (III) is preferably 5-95 mol%, more preferably 30-90%, even more preferably 50-80 mol%.

In addition, in the copolyester as a liquid crystalline polymer, in addition to the above-mentioned structural units (I) to (IV), other components may be copolymerized within the range that does not impair the effect of the present invention. As such a copolymerization component, aromatic dicarboxylic acids such as 3,3'-diphenyldicarboxylic acid and 2,2'-diphenyldicarboxylic acid, adipic acid, azelaic acid, sebacic acid, etc. can be used. acid, aliphatic dicarboxylic acids such as dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, or chlorohydroquinone, methylhydroquinone, 4,4'-bis Aromatic diols such as hydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, or 1,4-butanediol, 1,6-hexane Diol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and other aliphatic or alicyclic diols, or m-hydroxybenzoic acid, 2,6-hydroxynaphthalene Aromatic hydroxycarboxylic acid such as acid, p-aminophenol, p-aminobenzoic acid, etc.

The flow initiation temperature of the liquid crystalline polymer is preferably 200 to 360°C from the viewpoint of forming a network structure or voids, and more preferably 230 to 320°C from the viewpoint of miscibility with a non-liquid crystalline polyester described later.

Examples of non-ductile resins constituting at least a part of the non-ductile resin composition include polyolefins, polycarbonate, polystyrene, polyetherimide, polyether ketone, poly Ethersulfone, polysulfone, polylactic acid, etc.

In the composite film of the present invention, the non-ductile resin composition preferably further contains a polymer other than the non-ductile polymer. Alternatively, the composite film of the present invention of the first group has a film layer having a network structure, and preferably further contains a polymer other than a non-ductile polymer. By including a polymer other than the non-extensible polymer in the non-extensible resin composition, a layer that appropriately follows the thermoplastic resin composition when biaxially stretched as a composite film can form a network structure or voids with high productivity.

As a polymer other than a non-extensible polymer, it is preferable to be adjacent to a film layer having a network structure or a film layer composed of a non-extensible resin composition from the viewpoint of the adhesion between film layers and the effect of the present invention. The same polymer as the thermoplastic resin composition of the film layer. As such a thermoplastic resin composition, as mentioned above, polyester is particularly preferred, so that is to say, as a polymer other than non-ductile polymers, non-extensible polymers are also preferred. Liquid crystal polyester. Non-liquid crystalline polyester The polyester of the thermoplastic resin composition is also a polyester composed of an acid component such as an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, or an aliphatic dicarboxylic acid, and a diol component as described above.

The intrinsic viscosity of the non-liquid crystalline polyester used in combination with the liquid crystalline polymer is preferably 0.55 to 3.0 dl/g, more preferably 0.60, from the viewpoint of film forming stability or compatibility with the liquid crystalline polymer. -2.0dl/g.

The lower limit of the content of the liquid crystalline polymer to the film layer having a network structure or to the non-extensible resin composition is preferably 20% by weight or more, more preferably 30% by weight or more, still more preferably 35% by weight or more, and still more preferably 40% by weight or more. In addition, the upper limit is preferably 90% by weight or less, more preferably 85% by weight or less, further preferably 80% by weight or less, and still more preferably 70% by weight or less. When the content of the liquid crystal polymer is 20% by weight or more, a network structure or voids can be obtained, and when the content is 90% by weight or less, frequent occurrence of film formation damage can be suppressed.

The content of the liquid crystalline polymer relative to the entire composite film is preferably 3 to 30% by weight, more preferably 5 to 25% by weight, and still more preferably 7 to 23% by weight. When the content of the liquid crystal polymer relative to the entire composite film is 3% by weight or more, a network structure or voids can be sufficiently formed, and the specific gravity, cushioning, flexibility, and planarity of the composite film as described later can be obtained. The effect of improvement, etc. Moreover, by making it 30 weight% or less, the generation|occurrence|production of the breakage at the time of stretching can be suppressed.

The composite number of the composite film of the present invention is preferably 2-1000. As a composite positional relationship, when a film layer having a network structure or a film layer composed of a non-extensible resin composition is used as the A layer, and a biaxially stretched film layer made of a thermoplastic resin composition is used as the B layer and the C layer, From the standpoint of exhibiting the effects of the present invention and film processability and production efficiency, it is preferable to compound biaxially stretched layers made of thermoplastic resin on both surfaces of the A layer to form B/A/B, C/B/A/ Multi-layer structure of B/C, C/B/A/B, etc. In particular, focusing on suppressing deformation during film processing and maintaining planarity, a three-layer composite structure (B/A/B) in which layers of the same thickness formed of the same resin are composited on both outer surfaces of the A layer is particularly preferable.

The composite film of the present invention can also add nucleating agents, anti-thermal decomposition agents, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, pigments, dyes within the scope of not affecting the effects of the present invention. wait.

In addition, especially in the outermost layer of the composite film, in order to impart slipperiness, wear resistance, scratch resistance, etc. to the surface, it is also preferable to add organic lubricants such as fatty acid esters and waxes, or surfactants, Or inorganic particles or organic particles for forming surface protrusions. In addition, so-called internal particles can also be precipitated by adding a catalyst or the like during the polymerization reaction.

As the inorganic particles, for example, oxides such as silicon oxide, aluminum oxide, titanium oxide, magnesium oxide, and zirconium oxide, or composite oxides such as clay, mica, kaolin, talc, and montmorillonite, or calcium carbonate, carbonic acid, etc., can be used. Carbonates such as barium, sulfates such as calcium sulfate and barium sulfate, titanates such as barium titanate and potassium titanate, or phosphates such as calcium phosphate. Silica includes wet or dry silica or colloidal silica, and may be spherical or porous.

In addition, as the organic particles, as long as at least a part of the part constituting the particles is insoluble in the resin constituting the film, for example, polystyrene or cross-linked polystyrene particles, or styrene-acrylic and acrylic cross-linked particles can be used. Linked particles, vinyl-based particles such as styrene-methacrylic cross-linked particles, or particles such as benzoguanamine-formaldehyde, silicon, and polytetrafluoroethylene.

The surface roughness of the composite thin film can be adjusted by appropriately selecting the particle size, compounding amount, shape, etc. of the inorganic particles or organic particles for forming surface protrusions. The average particle diameter of the particles is preferably 0.01 to 3 μm, and the added amount is preferably 0.001 to 3% by weight. In addition, one kind of particles may be used alone, or two or more kinds of particles having different average particle diameters may be used in combination.

The thickness of the composite film of the present invention is generally preferably 500 μm or less as a whole, more preferably 0.5-400 μm, further preferably 10-300 μm, still more preferably 20-200 μm from the viewpoint of film application or workability. In addition, depending on the application, it is preferably 2.0-10 μm for magnetic tape applications, 0.5-15 μm for capacitor applications, 12-250 μm for circuit materials or release materials, and 75-400 μm for electrical insulating materials.

The film layer having a network structure or the film layer made of a non-ductile resin composition has a lower limit of preferably 1% or more, more preferably 10% or more, further preferably 15% or more, and still more preferably 20% or more of the total thickness of the composite film. , More preferably 30% or more. On the other hand, the upper limit is preferably 90% or less, more preferably 80% or less, further preferably 75% or less, further preferably 70% or less, still more preferably 60% or less. When it is 1% or more, the effect of improving thermal dimensional stability can be acquired, and when it is 10% or more, since the specific gravity of a composite film is reduced, cushioning property can be imparted. Moreover, by setting it as 90% or less, frequent occurrence of film damage can be prevented.

In the composite film of the present invention of the second group, it is important that the specific gravity is 0.2-1.2. In addition, the composite film of the present invention of the first group preferably has a specific gravity within this range. As the composite film of the present invention, the specific gravity is more preferably 0.3-1.0, still more preferably 0.4-0.7. The specific gravity being 1.2 or less means that the voids in the film are sufficient, and the effects of the present invention, such as cushioning properties of the film, can be obtained. On the other hand, by setting the specific gravity to 0.2 or more, a balance between strength and dimensional stability can be obtained without increasing voids in the film.

The composite film of the present invention preferably has a Young's modulus of 2-7 GPa both in the longitudinal direction (MD) and in the transverse direction (TD). The lower limit is more preferably 2.5 GPa, still more preferably 3 GPa. On the other hand, the upper limit is more preferably 6 GPa, and still more preferably 5 GPa. By being 7 GPa or less, deformation and curling can be suppressed, and shape stability can be improved. On the other hand, by being 2 GPa or more, the rigidity is maintained and the operability is not damaged.

The composite film of the present invention preferably has a heat shrinkage rate of 0-2% at 150° C. in both the machine direction (MD) and the transverse direction (TD) of the composite film from the viewpoint of heat resistance during film processing or use. The upper limit is more preferably 2.0% or less, more preferably 1.0% or less, still more preferably less than 1.0%, still more preferably 0.5% or less. By being 2% or less, heat resistance can be ensured and thermal dimensional stability can be obtained. Moreover, favorable planarity can be maintained by making thermal contraction rate 1.0 % or less. On the other hand, the lower limit is more preferably 0.01% or more. By being 0.01% or more, it is possible to prevent wrinkles due to film swelling and deterioration of planarity.

The thermal expansion coefficients of the composite film of the present invention are preferably 3-45 ppm/°C both in the longitudinal direction (MD) and in the transverse direction (TD). The lower limit is more preferably 4 ppm/°C or higher, still more preferably 5 ppm/°C or higher, still more preferably 10 ppm/°C or higher. The upper limit is more preferably 35 ppm/°C or less, still more preferably 30 ppm/°C or less, still more preferably 25 ppm/°C or less, still more preferably 20 ppm/°C or less. By being within such a range, curling due to thermal deformation can be prevented during processing in applications such as a film for circuit materials, a release film, or a printing material.

The composite film of the present invention preferably has a buffer rate of 10-50%, more preferably 15-45%, and more preferably 20-40%. By making the buffer rate more than 10%, the flexibility of the film is improved, such as improving the flexibility of wallpaper, etc. Processability when used in building materials, and cost reduction per unit area can also be expected. On the other hand, by setting the buffer ratio to 50% or less, the strength and dimensional stability of the composite film can be balanced and the production efficiency can be maintained.

The dielectric constant of the composite film of the present invention is preferably 1.3-3.0, more preferably 1.5-2.7, and even more preferably 1.7-2.5 at a temperature of 30°C and a frequency of 10KHz. By setting the dielectric constant to 3.0 or less, when used as an electrical insulating material, power loss due to leakage current or heat generation can be suppressed, and the effects of the present invention can be obtained. In addition, considering moderately controlling the porosity and obtaining a balance with the strength of the film or production efficiency, it is more sufficient if the dielectric constant is reduced to about 1.3.

In addition, the composite film of the present invention, in addition to the above-mentioned structure, can also directly or use layers such as adhesives to make other polymer layers such as polycarbonate, polyolefin, polyamide, polyvinylidene chloride or acrylic Layers composed of polymers and the like are used in combination.

In addition, the composite film of the present invention may be processed such as heat treatment, molding, surface treatment, lamination, coating, printing, embossing, etching, etc. depending on the application.

The composite film of the present invention can be suitably used in various industrial materials such as engineering materials, mold release materials, printing materials, molding materials, building materials, materials for magnetic recording media, circuit materials, and electrical insulating materials.

The network structure or voids in the composite film of the present invention can be produced as follows. That is, the method for producing a composite film of the present invention is a method for producing a composite film in which at least two layers of resin compositions are coextruded, wherein at least one layer of the composite film uses a thermoplastic resin composition, and the other at least one layer uses a non- A method for producing a ductile resin composition and a composite film in which cracks are formed in a layer using the non-ductile resin composition by biaxial stretching.

The thermoplastic resin composition and the non-liquid crystalline polyester such as polyethylene terephthalate can be produced by any of the following processes.

(1) Using terephthalic acid and ethylene glycol as raw materials, directly obtain low molecular weight polyethylene terephthalate or oligomers through esterification, and then use catalysts such as antimony trioxide or titanium compounds Polycondensation process.

(2) Using dimethyl terephthalate and ethylene glycol as raw materials to obtain low molecular weight products through transesterification, and then using catalysts such as antimony trioxide or titanium compounds for polycondensation.

The esterification of process (1) can be reacted even if there is no catalyst, and the transesterification reaction of process (2) can be carried out using compounds such as manganese, calcium, magnesium, zinc, lithium, titanium, etc. as catalysts. After the transesterification reaction is completed, a phosphorus compound may be added in order to deactivate the catalyst used for the reaction. Phosphorous acid, phosphoric acid, phosphoric acid triester, phosphonic acid, phosphonate, etc. are mentioned as a phosphorus compound, and 2 or more types may be used together.

The aforementioned esterification reaction or transesterification reaction is preferably carried out at a temperature of 130-260° C., and the polycondensation reaction is preferably carried out at a temperature of 220-300° C. under high vacuum.

As a more specific example of the production method of polyethylene terephthalate, esterification reaction of terephthalic acid and ethylene glycol, or transesterification of dimethyl terephthalate and ethylene glycol can be carried out. Reaction to produce bis-β-hydroxyethyl terephthalate (BHT). Then, the BHT was transferred to a polymerization tank, and heated to 280° C. under vacuum to carry out a polymerization reaction. Here, since a polyester with an intrinsic viscosity of about 0.5 is obtained, the polyester can be granulated, pre-crystallized at a temperature below 180°C, and then under a reduced pressure of about 133Pa (1mmHg) at 190-250°C, Solid phase polymerization was carried out for 10-50 hours.

In addition, various additives as described above may be added at any stage from the esterification reaction or the transesterification reaction to the polycondensation reaction.

In addition, as a method of including particles in polyethylene terephthalate, a method of dispersing particles in ethylene glycol in the form of a slurry and polymerizing the ethylene glycol and terephthalic acid is preferable. As a method of adding particles, for example, if the state of hydrosol or alcohol sol obtained at the time of particle synthesis is added without primary drying, the dispersibility of the particles is good. In addition, it is also effective to mix the particle slurry with the directly prescribed polyethylene terephthalate particles, and use a vented twin-screw kneading extruder to mix the polyethylene terephthalate. .

As a method of adjusting the particle content, it is effective to prepare a high-concentration particle masterbatch in advance by the above-mentioned method, and dilute the masterbatch with a flake substantially free of particles at the time of film formation to adjust the particle content.

PPS as a thermoplastic resin can be produced, for example, by reacting sodium sulfide and p-dichlorobenzene in an amide-based polar solvent such as N-methyl-2-pyrrolidone (NMP) at 230-280° C. under high pressure. At this time, caustic potash, an alkali metal carboxylate, or the like may be added as a polymerization degree regulator. After the polymerization, the polymer is cooled to make the polymer into a water slurry, which is filtered through a filter to obtain a granular polymer. The polymer is stirred in an aqueous solution of acetate or the like at 30-100°C for 10-60 minutes, washed several times with ion-exchanged water at 30-80°C, and dried to obtain PPS powder. The PPS powder is washed with NMP at an oxygen partial pressure of 1.3MPa (10 Torr), preferably below 66Pa (5 Torr), and then washed several times with ion-exchanged water at 30-80°C. Drying was carried out under reduced pressure. The PPS produced in this way is actually a linear polymer, and since the melt crystallization temperature Tmc is in the range of 160-190°C, it can be stably drawn into a film.

The non-ductile resin composition preferably contains the aforementioned copolyester as an example of the aforementioned liquid crystalline polymer, for example, when the aforementioned structural units (I) to (IV) do not contain the structural unit (III). The following method (3) or (4) is preferably the following method (5) when the structural unit (III) is contained.

(3) Diacylates of aromatic dihydroxy compounds such as p-acetoxybenzoic acid and 4,4'-diacetoxybiphenyl, 4,4'-diacetoxybenzene, etc., and terephthalic acid, etc. A method for producing aromatic dicarboxylic acids by deacetate polycondensation reaction.

(4) Reaction of aromatic dihydroxy compounds such as p-hydroxybenzoic acid and 4,4'-dihydroxybiphenyl, hydroquinone, and aromatic dicarboxylic acids such as terephthalic acid with acetic anhydride, and phenol After acylation of hydroxyl group, it is produced by polycondensation reaction of deacetate.

(5) Polymers of polyesters such as polyethylene terephthalate, oligomers, or bis (β- A method of producing by the method of (1) or (2) above in the presence of hydroxyethyl) ester.

The polycondensation reaction of the above methods (3)-(5) is also carried out without a catalyst, but it is sometimes preferable to add metal compounds such as stannous acetate, tetrabutyl titanate, potassium acetate, sodium acetate, antimony trioxide, and metal magnesium.

In addition, the above structural unit (I) can be produced, for example, from p-hydroxybenzoic acid and/or 6-hydroxy-2-naphthoic acid. And, the structural unit (II), for example, can be made of 4,4'-dihydroxybiphenyl, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl, hydroquinone, tertiary Butylhydroquinone, phenylhydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2'-bis(4-hydroxyphenyl)propane, 4,4'- Aromatic dihydroxy compounds such as dihydroxydiphenyl ether are produced. In addition, the structural unit (III) can be produced, for example, from ethylene glycol or the like. In addition, structural unit (IV) can be formed, for example, from terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,2-bis(phenoxy) Aroma of ethane-4,4'-dicarboxylic acid 1,2-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylic acid and 4,4'-diphenyl ether dicarboxylic acid Formation of dicarboxylic acids.

In the present invention, when the liquid crystalline polymer is mixed with other polymers, as a mixing method, there is a method of pre-melting and kneading (granulating) the liquid crystalline polymer and other polymers before melt extrusion. A method of making a master sheet, or a method of mixing and melt kneading during melt extrusion, etc. The method of making a master sheet is preferable in view of the quality of the film and the good film forming property because a uniform dispersion state is obtained.

Taking polyethylene terephthalate (PET) as the thermoplastic resin and Ueno Pharmaceutical Co., Ltd.'s liquid crystal polyester "Ueno LCP" 5000 as the liquid crystal polymer as an example, the process from the manufacture of the master sheet to the formation of the undrawn The stretched composite film will be described. In addition, "Ueno LCP" 5000 has (I) as the said structural unit.

The weight ratio of the liquid crystalline polymer to PET in the mother sheet is preferably 95/5 to 50/50.

As a method of mixing/kneading liquid crystal polymers and thermoplastic resins, for example, each of them can be melted and mixed in a melt extruder, or a Henschel mixer, a ball mill, a blender, a drum, etc. can be used. The mixer pre-mixes the powder raw materials in advance, and then melts and kneads them using a melt kneader.

As the melt kneading machine, for example, a twin-screw kneading extruder is preferable.

For example, after mixing pellets of liquid crystal polymers and pellets of PET etc. in a desired ratio for making master sheets, they are supplied to a vented twin-screw kneading extruder at 280-320°C. Melt kneading. In addition, as a vented twin-screw extruder, from the viewpoint of reducing poor dispersion, an extruder equipped with 3 twin-screws or 2 twin-screw type screws is preferred, and the residence time at this time is preferably 1-5 minutes. .

After making the master sheet thus prepared correspond to the desired content of the liquid crystalline polymer relative to the non-ductile resin composition, a sheet such as PET is mixed, dried in vacuum at about 180°C for more than 3 hours, and then placed in a compression zone and heated to In an extruder at a temperature of 270-320°C. When mixing with PET, it is more preferred that the temperature in the compression zone is 290-310°C.

On the other hand, PET or the like mixed with suitable particles is fed to another extruder after drying.

Furthermore, when these are melt-extruded, it is also desirable to perform filtration to remove foreign matter or deteriorated polymer in the extruder, and it is desirable to minimize foreign matter mixed into the film. As the filter used at this time, for example, sintered metal, porous ceramics, molding sand, metal mesh, etc. are preferably used.

In addition, it is also preferable to provide a gear pump in order to improve constant supply performance.

The various molten polymers passing through the extruder are collected and compounded in the feeding area, and are ejected into sheets from the narrow slit of the T-shaped die, so that the sheets are closely attached to the cooling surface at a surface temperature of 20-70°C. Cooling and solidification on rolls (casting rolls) can produce an unstretched film in a substantially non-oriented state.

Then, the unstretched film is biaxially stretched to biaxially orient the layer made of the thermoplastic resin composition, and to cause cracks in the layer made of the non-extensible resin composition. As the stretching method, sequential biaxial stretching method (a stretching method in which stretching in each direction such as a method of longitudinal stretching followed by transverse stretching) and simultaneous biaxial stretching method (longitudinal and transverse stretching methods) can be used stretching simultaneously), or a method combining these.

The stretching conditions and the like can be appropriately set depending on the multilayer configuration or the components of the resin composition constituting each layer, but generally, the following are preferable.

The stretch ratio is preferably 1.2 to 6.0 times, more preferably 2.5 to 4.5 times in the longitudinal direction and transverse direction of the film in multiple steps of one step or more.

The stretching temperature is preferably 90-180° C., and when the glass transition temperature of the thermoplastic resin composition using the layer of the thermoplastic resin composition is Tg (° C.), it is preferably Tg to Tg+40 (° C.).

In addition, re-stretching may be performed according to the application or desired film properties. The re-stretching ratio is preferably 1.1 times or more in the longitudinal direction and/or in the transverse direction.

The temperature of the post-stretching heat treatment is preferably 150-Tm(°C), more preferably 200-245°C when the melting point of the thermoplastic resin composition using the layer of the thermoplastic resin composition is Tm(°C). The time of heat treatment is preferably 0.3-30 seconds.

In addition, in order to obtain the effect of the present invention, it is also preferable to perform a relaxation treatment of 1-10% in the longitudinal direction and/or transverse direction, more preferably 9% or less, when the film is cooled during heat treatment and/or after heat treatment. gallop processing.

In addition, the composite film after coiling is also preferably subjected to aging treatment at a temperature of 50-120° C. for 5 minutes to 500 hours.

The following is an example of a sequential biaxial stretching method in which a layer using a thermoplastic resin composition is arranged on both sides of a layer using a non-extensible resin composition containing a liquid crystalline polymer. Be explained.

The unstretched polyester film is heated using a group of heating rolls. In this example, the stretching is preferably multi-step stretching, and it is particularly preferable to slightly stretch the longitudinal direction before stretching the longitudinal direction. This micro-stretching removes the accumulated deformation in and between the molecular chains of the polymer, facilitates subsequent stretching, and is beneficial to the formation of a network structure or voids in a layer using a non-ductile resin composition. The stretching ratio of such micro-stretching is preferably 1.05 to 1.8 times, more preferably 1.1 to 1.5 times, and still more preferably 1.15 to 1.3 times. In addition, as the stretching temperature for such micro-stretching, when the glass transition temperature of the thermoplastic resin composition using the layer of the thermoplastic resin composition is Tg (° C.), it is preferably Tg+10 to Tg+70 (° C.), more preferably Preferably Tg+15 to Tg+60 (°C), more preferably Tg+20 to Tg+50 (°C).

The stretching ratio in the longitudinal direction (MD direction) is preferably 2 to 5 times, more preferably 2.5 to 4.5 times, and still more preferably 3 to 4 times, including the aforementioned micro-stretching. In addition, this stretching ratio does not include the stretching ratio of the re-longitudinal stretching mentioned later. As the stretching temperature for longitudinal stretching, if the glass transition temperature of the thermoplastic resin composition using the layer of the thermoplastic resin composition is Tg (° C.), Tg-Tg+60 (° C.), more preferably Tg+5- Tg+55(°C), more preferably Tg+10-Tg+50(°C).

After longitudinal stretching, cooling is preferably performed using a group of cooling rolls at 20 to 50°C.

As a stretching method in the transverse direction (TD direction), for example, a tenter is preferably used. Both ends of the film can be clamped with clips, guided to a tenter, and stretched in the transverse direction. The lateral stretch ratio is preferably 2.0 to 6.0 times, more preferably 3.0 to 5.0 times, and still more preferably 3.5 to 4.5 times. In addition, this stretching ratio does not include the stretching ratio of the re-longitudinal stretching mentioned later. In addition, as the stretching temperature, if the glass transition temperature of the thermoplastic resin composition using the layer of the thermoplastic resin composition is Tg (°C), it is preferably Tg-Tg+80 (°C), more preferably Tg+10-Tg +70(°C), more preferably in the range of Tg+20-Tg+60(°C).

After transverse stretching, cooling is preferably performed using a group of cooling rolls at 20-50°C.

Furthermore, re-stretching in the longitudinal direction and/or re-stretching in the transverse direction may be performed according to desired film properties.

By heating the film using a group of heating rolls, re-stretching can be performed in the longitudinal direction. The re-longitudinal stretch ratio is preferably 1.1 to 2.5 times, more preferably 1.2 to 2.4 times, and still more preferably 1.3 times when the glass transition temperature of the thermoplastic resin composition using the layer of the thermoplastic resin composition is Tg (° C.). -2.3 times. In addition, the re-longitudinal stretching temperature is preferably Tg-Tg+100 (°C), more preferably Tg+20-Tg+80 (°C), and still more preferably Tg+40-Tg+60 (°C).

Re-stretching in the transverse direction can be performed using a tenter. The re-stretching ratio in the lateral direction is preferably 1.1 to 2.5 times, more preferably 1.15 to 2.2 times, and still more preferably 1.2 to 2.0 times. In addition, as the re-stretching temperature, if the glass transition temperature of the thermoplastic resin composition using the layer of the thermoplastic resin composition is Tg (°C), it is preferably Tg to 250 (°C), more preferably Tg+20 to 240 ( °C), more preferably Tg+40-220 °C.

After the stretching treatment, the film can be thermally fixed under tension or while relaxing the transverse sides. The heat setting temperature is preferably 150-250°C, more preferably 170-245°C, and still more preferably 190-240°C. The time required for heat fixing is preferably 0.2 to 30 seconds.

Furthermore, it is preferable to cool the film while relaxing it in the transverse direction in a temperature range of 40 to 180°C. The relaxation rate at this time is preferably 1 to 10%, more preferably 2 to 8%, and still more preferably 3 to 7%, from the viewpoint of reducing the transverse thermal contraction rate.

In addition, the composite film of the present invention can be obtained by winding the film after cooling it to room temperature.

Example

[measurement, judgment method]

(1) Intrinsic viscosity

From the solution viscosity and solvent viscosity measured in o-chlorophenol at 25° C. using an Ostwald viscometer, the intrinsic viscosity [η] was calculated by the following formula.

Viscosity was measured and calculated for each sample using three samples, and the average value was taken.

ηsp/C=[η]+K[η] ² ·C

In the formula, ηsp=(solution viscosity/solvent viscosity)-1, C is the dissolved polymer weight per 100ml of solvent (g/100ml, usually 1.2), and K is Herkin's constant (0.343).

(2) Glass transition temperature (Tg)

Specific heat measurement was carried out in accordance with JIS K7121 using the simulated isothermal method under the following equipment and conditions.

Device: Temperature-modulated DSC manufactured by TA Instrument

Determination conditions:

Heating temperature: 270-570K (RCS cooling method)

Temperature Correction: Melting Points of High Purity Indium and Tin

Temperature modulation amplitude: ±1K

Temperature modulation cycle: 60 seconds

Heating step: 5K

Sample weight: 5mg

Sample container: aluminum open container (22mg)

Comparative container: aluminum open container (18mg)

The glass transition temperature (Tg) was calculated using the following formula. Using three samples, the glass transition temperature was measured and calculated for each sample, and the average value was taken.

Tg=(extrapolated glass transition start temperature + extrapolated glass transition end temperature)/2

(3) Melting temperature (Tm)

DSC (RDC220) manufactured by Seiko Instrument Co., Ltd. was used as a differential scanning calorimeter, and Discussion (SSC/5200) manufactured by the above-mentioned company was used as a data analyzer, and 5 mg of the sample was melted and held at 300° C. on an aluminum tray. After 5 minutes, after rapid cooling and solidification, the temperature was raised from room temperature at a heating rate of 20°C/min. Let the peak temperature of the melting endothermic peak observed at this time be the melting temperature (Tm). Using three samples, the melting temperature was measured and calculated for each sample, and the average value was taken.

(4) Non-ductility of the resin composition

Put the resin composition on top of a polyimide film ("Capton" manufactured by Toray DuPont Co., Ltd.), and use a press molding machine at a temperature of 300°C (400°C when the melting point is 300°C or higher) and a pressure of 10kg/ ^cm2 . Down compression was carried out for 10 seconds, and degassing was carried out every 0.2 milliseconds for 8 times to obtain a sheet. According to ASTM-D882, the breaking strength of a sample with a width of 10 mm and a length of 20 mm of the prepared sheet was measured at a temperature of 100° C. and a tensile speed of 100 mm/min. Using three samples, the average elongation rate was judged to be 50% or less as "non-ductile".

(5) Residence time of polymer during melt extrusion

Add 1% by weight of carbon black as an indicator to the feeding part of the extruder, pass through the extruder, short pipe, and filter, and observe from the front end of the T-shaped die that the indicator is extruded together with the polymer. The time when the indicator is supplied to the feeding part of the extruder is t ₁ , carbon black starts to be discharged from the die together with the polymer, and then, the time is defined as follows when the discharged polymer becomes free of carbon black t ₂ , let (t ₂ -t ₁ ) be the residence time.

At time t ₂ , the total light transmittance of the central part of the cast film to light with a wavelength of 550 nm was measured using a spectrophotometer U-3410 manufactured by Hitachi, Ltd., and defined by the time t at which the following function F(t) is 0.98.

F(t)=(total light transmittance of cast film at time t after adding carbon black)/(total light transmittance of cast film before adding carbon black)

(6) Breakage frequency during film production

Observe the damage of the film during film making, and judge according to the following standards

⊚: There is no film breakage at all.

◯: Film breakage rarely occurs.

△: Film breakage occasionally occurs.

×: Film breakage occurred frequently.

(7) The specific gravity of the film

The sample was cut into a size of 4 cm x 5 cm, and the specific gravity was measured after immersing in water at 230° C. for 1 minute using a hydrometer (SD-120L manufactured by MIRAJU Trading Co., Ltd.) using the water displacement method specified in JIS K7112. This measured value was converted into 25 degreeC specific gravity.

(8) Dielectric constant of the film

Measurement was performed in accordance with JISC2318. After vapor-depositing aluminum on both sides of the film, use a dielectric constant measuring device (DEA2970 manufactured by TA Instruments) to measure at a temperature of 30°C and a frequency of 10KHz. Three samples are used to measure the dielectric constant for each sample, and the average value is taken. .

(9) Young's modulus

According to the method specified in ASTM-D882, the measurement was carried out using an Instron type tensile tester ("Tensilon AMF/RTA-100", an automatic measuring device for film strength and elongation manufactured by Orientec Co., Ltd.). The measurement was performed under the following conditions. Using 10 samples, the Young's modulus was measured for each sample, and the average value was taken.

Sample size: width 10mm × fastening interval 100mm

Tensile speed: 10mm/min

Measurement environment: temperature 23°C, humidity 65%RH

(10) Heat shrinkage rate

According to JIS C2318, the measurement was carried out under the following conditions. Using 10 samples, the heat shrinkage rate was measured for each sample, and the average value was taken.

Sample size: width 10mm, marking interval 200mm

Measurement conditions: temperature 150°C, treatment time 30 minutes, no load

The heat shrinkage rate at 150°C was obtained from the following formula.

Thermal shrinkage rate (%)=[(L0-L)/L0]×100

L0: marking interval before heat treatment

L: marking interval after heat treatment

(11) Coefficient of thermal expansion

A thermomechanical measurement device (TMA/SS6100 manufactured by Seiko Instruments Co., Ltd.) was used. Apply a load of 3g to a sample with a sample width of 4mm and a sample length (distance between clamps) of 20mm, and raise the temperature from room temperature to 170°C at a heating rate of 10°C/min, and keep it for 10 minutes. The temperature was then lowered to 40°C at a rate of 10°C/min and maintained for 20 minutes. The coefficient of thermal expansion α (1/°C) was obtained from the amount of dimensional change from 150°C to 50°C when the temperature was lowered at this time using the following formula. The coefficient of thermal expansion was measured for each sample using three samples, and the average value was taken.

α={(L150-L50)/L0}/ΔT

L0: Initial specimen length at 23°

L150: The length of the sample at 150°C during cooling

L50: The length of the sample at 50°C during cooling

ΔT: Temperature change (150-50=100)

(12) Dimensional stability of film

On the film side of the copper-clad polyimide film described in JIS C6472, use a general-purpose vinyl chloride resin and an adhesive made of a plasticizer to attach the film to be measured. cm ² ), pressure bonding was carried out using a roller under the condition of 30 minutes. Cut out a sample of 25 cm in the MD direction x 25 cm in the TD direction from the obtained pressure-bonded film, place it on a fixed plate, observe the crimping state of the square in this state, and calculate the average value of the deflection (mm) of the square, and press The following criteria were evaluated.

◎ and ○ are qualified

◎: The amount of warpage is less than 5mm

○: The amount of warping is more than 5mm and less than 10mm

×: The amount of warping is 10 mm or more.

(13) film buffer rate

For a sample cut into 5cm x 5cm, use a dial indicator (manufactured by Mitutoyo Corporation) equipped with a standard measuring element (No. 2109-10) with a φ3mm hard ball, and apply a load of 50g to the upper part of the pressurized part. The thickness when this state is maintained for 30 seconds is read. Moreover, the load of 500g was similarly applied to the other part of the same sample, and the film thickness at the time of maintaining this state for 30 seconds was read. Then, the buffer rate was calculated from the following formula. Five samples were used, the buffer rate was measured for each sample, and the average value was taken.

Buffer rate (%)=[1-(film thickness at 500g load)/(film thickness at 50g load)]×100

(14) Planarity

Cut the film sample into a size of 25 cm in MD x 25 cm in TD, place it on a smooth table in an unloaded state, and treat it at a temperature of 160° C. for 30 minutes. Then spread out on a cork table, using a handle wrapped with a non-woven surface to flatten the surface of the film and completely remove the air between the film and the table. After standing for 3 minutes, the state of the film was observed, and the number of parts of the film raised from the stage was counted. The number of bulges is "⊚" for 5 or less, "○" for 6 or more and 10 or less, "△" for 11 or more and 15 or less, and "×" for 16 or more.

(15) Leakage current of electrical insulating materials

Make the film into a slot liner and wedge and put it into the engine, combine the refrigerant and oil of AC9000 and VG32 to measure the leakage, and make the following judgments.

○: Leakage is less than 0.8 mA.

△: Leakage 0.8-1mA.

×: Leakage exceeds 1 mA.

(16) Layer thickness ratio

Embed the film sample in epoxy resin, cut it in the longitudinal direction and thickness direction of the film, take a transmission electron microscope photo of the cut surface, measure the thickness of the specific layer and the entire composite film from the photo, and calculate the specific layer Thickness ratio relative to the overall thickness of the composite film.

(17) Porosity in layer, diameter of linear constituents

The film sample was cut parallel to the film surface to expose the cut surface of the layer with voids and the like, and a transmission electron micrograph was taken. The image of this photograph was analyzed using image analysis software, and the void ratio in the layer was measured.

In addition, when the network structure is observed on the cut surface, the short diameter Di is measured for 100 points arbitrarily extracted from the linear constituent elements forming the network structure, and the average diameter D is obtained from the following formula, and the linear structure The diameter of the feature.

D＝∑Di/100

[Example 1]

(Synthesis of PET)

Calcium acetate was added as a transesterification catalyst to a mixture of 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol at 140°C, heated to 230°C, and methanol was distilled off to perform transesterification. Then, antimony trioxide as a polymerization catalyst and phosphoric acid as a heat stabilizer were added to the product of this transesterification reaction, and it transferred to the polycondensation reaction tank. Next, slowly reduce the pressure in the reaction system to 0.1kPa while heating from 230°C to 290°C, stir the interior at 290°C under reduced pressure, and polymerize while distilling off methanol. The synthetic intrinsic viscosity is 0.62, and the glass transition temperature Polyethylene terephthalate (PET) with a melting point of 78°C and a melting point of 255°C, basically without adding particles (also known as particle-free PET).

(Manufacture of resin composition B)

Agglomerated silica particles with an average diameter of 2.5 μm were added to the above-mentioned particle-free PET flakes so that the content was 2% by weight to prepare a master flake for adding particles, and then the master flake was mixed with the aforementioned particle-free PET flakes, The particles were adjusted to 0.1% by weight, vacuum-dried at 180°C for 3 hours, and then supplied to extruder I whose compression zone was heated to 280°C.

The resin compositions obtained in each of the examples and comparative examples in this way are collectively referred to as "resin composition B", and the layer composed of resin composition B is collectively referred to as "B layer".

(Manufacture of resin composition A)

50 parts by weight of the above-mentioned particle-free PET sheet and 50 parts by weight of "Ueno LCP" 5000 (called LCP1) manufactured by Ueno Pharmaceutical Co., Ltd. as a liquid crystal polymer were vacuum-dried at 180° C. for 3 hours, and then put into the kneading zone and heated to In a vented co-rotating twin-screw kneading extruder (screw diameter 25mm, screw length/screw diameter = 28) at 290°C, melt extrusion under the conditions of screw rotation speed 200 rpm and residence time 2 minutes, Discharged in strips, cooled in cold water, and sliced immediately to obtain blended polymer flakes. The elongation at which non-ductility was judged was 20%. After the blended polymer sheet was vacuum-dried at 180°C for 3 hours, it was supplied to extruder II whose compression zone was heated to 280°C.

The resin compositions obtained in each of the Examples and Comparative Examples are collectively referred to as "resin composition A", and the layer composed of the resin composition A is collectively referred to as "A layer".

(Manufacture of unstretched composite film)

Resin compositions A and B molten in each extruder were filtered through filters, and a three-layer composite of B/A/B was formed using a rectangular manifold (feeding die) for three layers. The flow rate of the polymer passing through the manifold is controlled by adjusting the number of rotations of the gear pumps installed in each pipeline to control the amount of extrusion and confluence, so that the total thickness of the final composite film after stretching/relaxation is 50 μm, The composite thickness ratio is B/A/B=1/1/1.

Extrude such composite molten polymer, on the casting roller with surface temperature of 25°C, apply static electricity to make the polymer close to the roller to cool and solidify, according to the stretching ratio (die gap gap/unstretched film thickness Ratio) 8 coiled to obtain an unstretched composite film.

(stretch/relax treatment)

Using a longitudinal stretching machine composed of heated rollers, using the difference in peripheral speed of the rollers, stretch the unstretched composite film along the longitudinal direction of the film at a stretching temperature of 100°C and a stretching ratio of 3.5 times. stretch. Then, both ends of the film were clamped with clips, guided to a tenter, and stretched in the transverse direction of the film at a stretching temperature of 105° C. and a stretching ratio of 3.7 times.

Then, after heat treatment at 235°C for 3 seconds, 3% relaxation treatment is carried out in the lateral direction in the cooling zone controlled to 150°C, and then 1% relaxation treatment is carried out in the lateral direction in the cooling zone controlled to 100°C, followed by cooling After reaching room temperature, the edge of the film was removed to obtain a composite film with a thickness of 50 μm (the thickness of each layer of the A layer and the B layer is 16.7 μm, that is, the thickness ratio of the A layer is 33%).

The film of this example was not damaged during film production, and the production efficiency was also good.

The composition and physical properties of the obtained composite film are shown in Table 1-3. In the composite film of this embodiment, the layer A composed of the resin composition A containing liquid crystalline polymer has a network structure, has a small coefficient of thermal expansion, low rigidity, and good dimensional stability when used as a circuit material. In addition, low dielectric properties are also good. The average diameter of the fibrils which are the linear constituents forming the network structure was 3.5 μm.

[Example 2]

A composite film was produced in the same manner as in Example 1 except that the thickness ratio of B/A/B in the composite film thickness of 50 μm was changed to 12.5/25/12.5.

[Example 3]

In the production of the resin composition A, a liquid crystalline polyester having the following composition, a melting point of 265° C., and a molecular weight of 18,000 (called LCP2) was used as a liquid crystalline polymer.

(Copolymerization composition of LCP2)

p-Hydroxybenzoic acid 56.8 mol%

4,4′-Dihydroxybiphenyl 5.9 mol%

Ethylene glycol 15.7 mol%

Terephthalic acid 21.6 mol%

In addition, the weight ratio of PET/LCP2 in the resin composition A was changed to 30/70. The elongation at which non-ductility was judged was 15%.

Except for these, it carried out similarly to Example 1, and produced the composite film.

[Example 4]

(PPS resin)

Instead of the particle-free PET of Example 1, a linear PPS resin ("Lighton" T1881, glass transition temperature 92° C., melting point 285° C.) manufactured by Toray Co., Ltd. was used.

(Manufacture of resin composition B)

Add 0.2% by weight of silicon dioxide powder with an average particle size of 0.7 μm and 0.05% by weight of calcium stearate to the above PPS resin, and use the uniformly dispersed mixture as resin composition B. After vacuum drying at 180°C for 3 hours, supply The compression zone is heated to 295°C in extruder I.

(Manufacture of resin composition A)

After drying 50 parts by weight of the above-mentioned PPS resin ("Rayton" T1881) and 150 parts by weight of LCP at 180°C for 3 hours, put it into the mixing zone and heat it to 305°C for exhaust type co-rotating twin-screw mixing extrusion In the machine (screw diameter 25mm, screw length/screw diameter=28), it is melted and extruded under the conditions of screw rotation number 200 rpm and residence time 90 seconds, and is discharged in strips. After cooling with cold water, it is sliced immediately to obtain Hybrid polymer flakes. The elongation at which non-ductility was judged was 10%.

This blended polymer sheet was used as resin composition A, vacuum-dried at 180° C. for 3 hours, and then supplied to extruder II heated to 300° C. in the compression zone.

(Manufacture of unstretched composite film)

An unstretched composite film was produced in the same manner as in Example 1 except that the above-mentioned resin compositions A and B were used and the draw ratio was 5.

(stretch/relax treatment)

Using the same longitudinal stretching machine as in Example 1, this unstretched film was stretched in the longitudinal direction of the film at a stretching temperature of 105° C. and a stretching ratio of 3.1 times. Then, using a tenter in the same manner as in Example 1, stretching was carried out in the transverse direction of the film at a stretching temperature of 115° C. and a stretching ratio of 3.2 times.

After heat treatment for 3 seconds at a temperature of 255°C, 4% relaxation treatment is carried out in the lateral direction in a cooling zone controlled to 150°C, and then 1% relaxation treatment is carried out in a lateral direction in a cooling zone controlled to 100°C, and then cooled to After room temperature, the edge of the film was removed to obtain a composite film with a thickness of 50 μm (the thickness of each layer of A layer and B layer was 16.7 μm, that is, the thickness ratio of A layer was 33%). The film of this example was not damaged during film production, and the production efficiency was also good.

The composition and physical properties of the obtained composite film are shown in Table 1-3. The composite film of this embodiment has a network structure in the layer A formed by the resin composition A containing liquid crystalline polymer, and its coefficient of thermal expansion is significantly smaller than that of the single-layer PPS film shown in Comparative Example 2, and its rigidity is also small. Properties suitable as circuit materials. In addition, low dielectric properties are also good. The average fibril diameter of the linear constituents forming the network structure was 3 μm.

[Comparative example 1]

A film was produced in the same manner as in Example 1, except that only the same resin composition B as that used in Example 1 was used, and a single-film PET film with a thickness of 50 μm was used.

[Comparative example 2]

A film was produced in the same manner as in Example 4, except that only the same resin composition B as that used in Example 4 was used, and a single-film PPS film with a thickness of 50 μm was used.

[Comparative example 3]

The weight ratio of PET/LCP1 in resin composition A was changed to 95/5. The elongation at which non-ductility was judged was 500%.

Except for this, a composite film was produced in the same manner as in Example 1.

Resin composition A is not the non-ductile composite film of Comparative Example 3, and there is no network structure in the A layer, and the properties of the obtained film are not much different from those of the PET film of Comparative Example 1.

[Comparative example 4]

A composite film was trial-produced in the same manner as in Example 1 except that the weight ratio of PET/LCP1 in the resin composition A was changed to 5/95.

However, since film breakage occurred many times, stable film formation was not possible, and the produced film did not have a network structure in the A layer, and the surface properties of the film were not good.

Table 1 shows the results of the layer configurations of Examples 1-4 and Comparative Examples 1-4.

Table 1

layer composition Layer B A layer The amount of liquid crystalline polymer relative to the total composite film (% by weight) Resin composition (weight ratio) Thickness ratio (%) Example 1 B/A/B PET PET/LCP1(50/50) 33 6 Example 2 B/A/B PET PET/LCP1(50/50) 50 10 Example 3 B/A/B PET PET/LCP2(30/70) 33 9 Example 4 B/A/B PPS PPS/LCP1(50/50) 33 8 Comparative example 1 B PET - 0 0 Comparative example 2 B PPS - 0 0 Comparative example 3 B/A/B PET PET/LCP1(95/5) 33 2 Comparative example 4 B/A/B PET PET/LCP1(5/95) 33 25

In addition, the evaluation results of Examples 1-4 and Comparative Examples 1-4 are shown in Tables 2 and 3.

Table 2

The network structure of layer A Breakage frequency during film production specific gravity Permittivity Example 1 have ◎ 0.80 2.6 Example 2 have ◎ 0.70 1.7 Example 3 have ○ 0.61 1.9 Example 4 have ◎ 0.78 2.1 Comparative example 1 none ○ 1.39 3.3 Comparative example 2 none ○ 1.40 3.0 Comparative example 3 none ◎ 1.38 3.2 Comparative example 4 none × - -

table 3

Young's modulus (MD/TD) (GPa) Thermal shrinkage rate (MD/TD) (%) Coefficient of Thermal Expansion (MD/TD) (ppm/℃) Dimensional stability Leakage Example 1 3.2/3.4 0.4/0.2 24/22 ◎ △ Example 2 3.0/3.2 0.2/0.2 18/17 ◎ ○ Example 3 3.2/3.4 0.4/0.2 21/20 ◎ ○ Example 4 3.1/3.3 0.3/0.2 28/24 ◎ ○ Comparative example 1 4.4/4.5 1.6/0.9 34/32 × × Comparative example 2 4.2/4.3 1.5/0.6 53/52 × × Comparative example 3 4.2/4.4 1.5/0.5 35/31 × × Comparative example 4 - - - - -

[Example 5]

(Synthesis of PET)

0.1 part by weight of magnesium acetate tetrahydrate was added to 194 parts by weight of dimethyl terephthalate and 124 parts by weight of ethylene glycol, heated to 230° C., and transesterification was carried out while methanol was being distilled off. Then add ethylene glycol solution of 0.05 parts by weight of trimethyl phosphate, and 0.05 parts by weight of antimony trioxide. After stirring for 5 minutes, the reaction system is slowly raised from 230°C to 290°C while stirring the oligomer at 30 rpm. ℃, while reducing the pressure to 0.1kPa. The time to reach the final temperature and final pressure is 60 minutes. Polymerize for 3 hours, when the specified stirring torque is reached, purge the reaction system with nitrogen, return to normal pressure, stop the polycondensation reaction, extrude into cold water in the form of strips, and immediately cut into pieces to obtain particles with an intrinsic viscosity of 0.62 and basically no additives Granules of polyethylene terephthalate (PET) (also known as particle-free PET). The glass transition temperature of the particle-free PET was 78°C and the melting point was 255°C.

(Manufacture of resin composition B)

Agglomerated silica particles with an average diameter of 2.5 μm were added to the above-mentioned particle-free PET pellets to make the content 2% by weight to prepare a master sheet for adding particles, and then the master sheet was compounded with the above-mentioned particle-free PET pellets. The mixed particles were 0.1% by weight, and vacuum-dried at 180°C for 3 hours to obtain a resin composition B, which was supplied to an extruder I whose compression zone was heated to 280°C.

(Manufacture of resin composition A)

After 50 parts by weight of the above-mentioned particle-free PET sheets and 150 parts by weight of LCP were vacuum-dried at 180°C for 3 hours, they were put into a vented co-rotating twin-screw mixing extruder (screw diameter 25mm) heated to 290°C in the mixing zone. , screw length/screw diameter=28), under the conditions of screw rotation number 200 rpm and residence time 2 minutes, melt extrusion is discharged in strips, and after cooling in cold water, slice immediately to obtain blended polymer sheets. The elongation at which non-ductility was judged was 20%.

The blended polymer sheet was vacuum-dried at 180°C for 3 hours to obtain a resin composition B, which was supplied to the extruder II whose compression zone was heated to 280°C.

(Manufacture of unstretched composite film)

Resin compositions A and B melted in each extruder were filtered through filters, and a three-layer composite of B/A/B was formed using a rectangular manifold (feeding die) for three layers. The flow rate of the polymer passing through the manifold is controlled by adjusting the number of rotations of the gear pumps installed in each pipeline to control the amount of extrusion and confluence, so that the total thickness of the final composite film after stretching and relaxation treatment is 50 μm. The thickness ratio is B/A/B=20/60/20.

Extrude such composite molten polymer, on the casting roll with surface temperature of 25°C, apply static electricity while making the polymer close to the roll to cool and solidify, according to the stretch ratio (die gap/unstretched film Ratio of thickness) 8 coiled to obtain an unstretched composite film.

(stretch/relax treatment)

Stretch the unstretched composite film in the longitudinal direction of the film at a stretching temperature of 105°C and a stretching ratio of 1.2 times using a roll stretching machine, and then stretch it at a stretching temperature of 85°C and a stretching ratio of 3.0 times. Stretch down. Then, the film was stretched in the transverse direction using a tenter at a stretching temperature of 100° C. and a stretching ratio of 4.0 times.

Next, after heat treatment at a temperature of 230°C for 10 seconds at a fixed length, a 1% relaxation treatment was performed in the transverse direction at 200°C to obtain a composite film with a thickness of 50 μm.

The composition and characteristics of the obtained composite film are shown in Tables 4-6. The composite film is a film with low dielectric properties, cushioning or softness, low thermal expansion and good planarity.

[Example 6-9]

A composite film was produced in the same manner as in Example 5, except that the content of the liquid crystal polymer LCP1 relative to the resin composition A or the thickness ratio of the A layer was changed as shown in Table 4.

The composition and characteristics of the obtained composite film are shown in Tables 4-6. These composite films are also films with low dielectric properties, good cushioning and flexibility, low thermal expansion, and good planarity. The elongation at which non-ductility was judged was 25% (Example 6), 40% (Example 7), and 5% (Example 8). In Examples 6-8, the A layer composed of the resin composition A has a quasi-network structure in which the voids are continuous in the longitudinal direction on the surface parallel to the film surface, or the elements constituting the mesh are interrupted midway. However, Example 9 has a network structure in the A layer.

[Example 10]

As the liquid crystalline polymer, LCP2 was used instead of LCP1. The elongation at which non-ductility was judged was 30%. Other than that, a composite film was produced in the same manner as in Example 5.

The composition and characteristics of the obtained composite film are shown in Tables 4-6. The composite film is also a film with low dielectric properties, cushioning and softness, low thermal expansion and good planarity.

[Example 11]

As the liquid crystalline polymer, liquid crystalline polyester (called LCP3) with the following composition and a melting point of 220°C is used.

Copolymerization composition of LCP3

p-Hydroxybenzoic acid 31.2 mol%

4,4′-Dihydroxybiphenyl 4.9 mol%

Ethylene glycol 29.5 mol%

Terephthalic acid 34.4 mol%

The elongation to judge non-ductile is 45%.

Other than that, a composite film was produced in the same manner as in Example 5.

The properties of the obtained composite film are shown in Tables 4-6. The composite film is a film with low dielectric properties, low thermal expansion and good planarity.

[Example 12]

In the manufacture of the resin composition A of Example 4, as the liquid crystalline polymer, instead of LCP1, a liquid crystalline resin manufactured by Toray Co., Ltd. (“Siberas” (registered trademark), melting point 315° C.) (called LCP4) was used, and The heating temperature of the kneading zone of the vented co-rotating twin-screw kneading extruder was 325°C. The elongation at which non-ductility was judged was 15%. Other than these, it carried out similarly to Example 4, and produced the composite film.

The properties of the obtained composite film are shown in Tables 4-6. The composite film has low thermal expansion and good dielectric properties.

[Example 13]

(Manufacture of resin composition B)

Resin composition B was manufactured similarly to Example 5, and it supplied to extruder I.

(Manufacture of resin composition A)

Instead of the liquid crystal polymer LCP1 of Example 5, 40 parts by weight of polymethylpentene (Mitsui Chemicals DX820) (PMP) was used, and instead of the particle-free PET of Example 5, polymethylpentene with a molecular weight of 4000 was used as a dispersant. 60 parts by weight of ethylene glycol (PEG) 6 weight percent copolymerized PET, these are mixed, after vacuum drying at 180 ° C for 3 hours, put into the exhaust type co-rotating twin-screw mixing and extruding that is heated to 290 ° C in the mixing zone In the machine (screw diameter 25mm, screw length/screw diameter = 28), under the conditions of screw rotation number 200 rpm and residence time 2 minutes, melt extrusion is discharged in strips, after cooling in cold water, slice immediately to obtain blending polymer sheet. The elongation at which non-ductility was judged was 45%. The blended polymer sheet was vacuum-dried at 180°C for 3 hours, and then supplied as a resin composition A to an extruder II whose compression zone was heated to 280°C.

(Manufacture of unstretched composite film)

Resin compositions A and B molten in each extruder were filtered through filters, and a three-layer composite of B/A/B was formed using a three-layer multi-collection pipe die (nozzle composite). The flow rate of the polymer passing through the multi-collecting pipe die is controlled by adjusting the number of rotations of the gear pump installed in each pipe, and the flow is controlled so that the total thickness of the final composite film after stretching and relaxation treatment is 50 μm. , the composite thickness ratio is B/A/B=20/60/20.

Extrude the molten polymer compounded in this way, on the casting roll with a surface temperature of 25°C, apply static electricity while making the polymer close to the roll to cool and solidify, according to the stretch ratio (die gap/unstretched film thickness) Ratio) 8 coiled to obtain an unstretched composite film.

(stretch/relax treatment)

This unstretched film was stretched in the same manner as in Example 5 to obtain a composite film.

The properties of the obtained composite film are shown in Tables 4-6. This composite film is good in low dielectric properties, and is also at acceptable levels regarding low thermal expansion and planarity.

[Example 14]

A composite film was produced in the same manner as in Example 5 except that polyetherimide ("Ultem" 1010) (PEI) manufactured by GE Plastics was used instead of the liquid crystalline polymer LCP1 of Example 5.

The properties of the obtained composite film are shown in Tables 4-6. This composite film is good in low dielectric properties, and is also at acceptable levels regarding low thermal expansion and planarity.

[Comparative example 5, 6]

A composite film was produced in the same manner as in Example 5, except that the content of the liquid crystalline polymer LCP1 relative to the resin composition A and the thickness ratio of the A layer were changed as shown in Table 4.

The characteristics of the obtained composite film are shown in Tables 5 and 6. It is a film whose specific gravity is outside the range of the present invention, and whose low dielectric properties, cushioning properties, flexibility, low thermal expansion, and planarity are insufficient.

[Comparative Example 7]

A film was produced in the same manner as in Example 5, except that only the same resin composition B as in Example 5 was used to produce a single-film PET film with a thickness of 50 μm.

The properties of the obtained film are shown in Tables 5 and 6, and it was a film with insufficient low dielectric properties, cushioning properties, flexibility and low thermal expansion.

Table 4

layer composition B layer A layer The amount of liquid crystalline polymer relative to the total composite film (% by weight) Resin composition (weight ratio) Thickness ratio (%) Example 5 B/A/B PET PET/LCP1(50/50) 60 12 Example 6 B/A/B PET PET/LCP1(65/35) 75 10 Example 7 B/A/B PET PET/LCP1(72/28) 80 10 Example 8 B/A/B PET PET/LCP1(10/90) 15 3 Example 9 B/A/B PET PET/LCP1(50/50) 50 6 Example 10 B/A/B PET PET/LCP2(50/50) 60 12 Example 11 B/A/B PET PET/LCP3(50/50) 60 12 Example 12 B/A/B PPS PPS/LCP4(50/50) 60 12 Example 13 B/A/B PET PET/PMP(60/40) 60 - Example 14 B/A/B PET PET/PEI(50/50) 60 - Comparative Example 5 B/A/B PET PET/LCP1(70/30) 15 2 Comparative Example 6 B/A/B PET PET/LCP1(50/50) 80 32 Comparative Example 7 B PET - 0 0

table 5

The network structure of layer A specific gravity Buffer rate (%) Permittivity Example 5 have 0.56 30 1.7 Example 6 have 0.66 twenty one 2.6 Example 7 have 0.72 17 2.8 Example 8 have 1.05 12 2.7 Example 9 have 0.68 twenty three 1.6 Example 10 have 0.58 27 2.0 Example 11 have 0.70 18 2.7 Example 12 have 0.72 twenty one 2.0 Example 13 have 0.45 35 1.5 Example 14 have 0.82 15 2.3 Comparative Example 5 none 1.23 7 2.9 Comparative example 6 none 0.18 55 1.5 Comparative example 7 none 1.38 5 3.3

Table 6

Young's modulus (MD/TD) (GPa) Thermal shrinkage (MD/TD)(%) Coefficient of thermal expansion (MD/TD) (ppm/℃) Planarity Leakage Example 5 2.7/2.8 0.3/0.2 17/16 ◎ ○ Example 6 3.1/3.2 0.4/0.2 18/17 ◎ ○ Example 7 3.6/3.8 0.5/0.2 22/23 ○ △ Example 8 3.8/4.2 0.7/0.3 26/25 △ △ Example 9 3.0/3.0 0.3/0.2 18/17 ○ ○ Example 10 3.3/3.5 0.3/0.2 17/16 ◎ ○ Example 11 3.7/3.8 0.2/0.2 24/22 ○ △ Example 12 3.2/3.4 0.3/0.2 24/23 ○ ○ Example 13 2.4/2.3 0.4/0.2 32/31 △ ○ Example 14 3.0/3.2 0.2/0.2 38/36 △ ○ Comparative Example 5 4.1/4.6 1.2/0.5 31/31 × × Comparative example 6 1.4/1.5 0.4/0.3 13/12 × ○ Comparative example 7 4.5/5.0 2.1/0.9 35/33 × ×

[Comparative Example 8]

A composite film was trial-produced in the same manner as in Example 5, except that the same resin compositions A and B as in Example 5 were used, and the layer configuration was reversed to A/B/A.

However, film breakage occurred many times during stretching, and a biaxially stretched composite film could not be obtained.

[Comparative Example 9]

Trial production was carried out in the same manner as in Example 5, except that the same resin compositions A and B used in Example 5 were used, the film layer was configured as a two-layer structure of A/B, and the composite thickness ratio was A/B=1/2. Composite film.

However, film breakage occurred many times during stretching, and a biaxially stretched composite film could not be obtained.

Claims (13)

1. laminated film, it is the laminated film that is made of at least 3 layers film, at least 1 layer is that cancellated film is arranged, and is compounded with the layer of the biaxial tension that thermoplastic resin makes in two outsides of this layer.

2. the described laminated film of claim 1 is characterized in that, aforementioned have cancellated thin layer to be made of the resin combination of non-ductility.

3. the described laminated film of claim 1 is characterized in that, aforementioned have cancellated thin layer to contain liquid-crystalline polymer.

4. the described laminated film of claim 3 is characterized in that, aforementioned have cancellated thin layer also to contain non-liquid crystalline polyester.

5. the described laminated film of claim 4 is characterized in that, non-liquid crystalline polyester is PETG, PEN or its modifier.

6. the described laminated film of claim 3 is characterized in that, the content of cancellated thin layer is arranged is 20-90 weight % to liquid-crystalline polymer with respect to aforementioned.

7. the described laminated film of claim 3 is characterized in that, the liquid-crystalline polymer content whole with respect to laminated film is 3-30 weight %.

8. the described laminated film of claim 1 is characterized in that, aforementioned the thickness of cancellated thin layer is arranged is the 1-90% of the whole thickness of laminated film.

9. the described laminated film of claim 8 is characterized in that, aforementioned the thickness of cancellated thin layer is arranged is the 10-80% of the whole thickness of laminated film.

10. the described laminated film of claim 1 is characterized in that, the thermoplastic resin composition of the thin layer of biaxial tension is contained at least a kind that is selected from polyester, polyphenylene sulfide, PEI, Merlon, polyether-ketone, polyether sulfone, polysulfones, PLA.

11. the described laminated film of claim 1 is characterized in that, the vertical and horizontal Young's modulus of laminated film all is 2-7GPa.

12. the described laminated film of claim 1 is characterized in that, the vertical and horizontal percent thermal shrinkage under 150 ℃ of temperature of laminated film all is 0-2%.

13. the described laminated film of claim 1 is characterized in that, the vertical and horizontal thermal coefficient of expansion of laminated film all is 3-45ppm/ ℃.

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