JP2015176921A - Coverlay for high frequency circuit board, and base material for flexible flat cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coverlay and a base material for flexible flat cable (FFC), each having a polyimide film and a fluorine resin used therein, which is superior in the adhesion between a polyimide film layer and a fluorine resin layer, especially the adhesion after having gone through a process under a high-temperature and high-humidity condition.SOLUTION: A coverlay or base material for a flexible flat cable (FFC) comprises: a polyimide film layer; and a fluorine resin layer. Even after an elapse of 96 hours under the environment of 85°C and 85 RH%, the adhesion force (damp-proof adhesion force) between the polyimide film layer and the fluorine resin layer is still retained to be 50% or larger to an initial adhesion force between the polyimide film layer and the fluorine resin layer.

Description

  The present invention relates to a high-frequency circuit board cover lay and a flexible flat cable base material having excellent moisture-proof adhesion.

Flexible printed circuit boards (hereinafter also referred to as FPCs) and flexible flat cables (hereinafter also referred to as FFCs) are widely used in electronic and electrical devices such as mobile phones, tablets, and hard disks of personal computers. In general, an FPC is formed by processing a copper clad laminate (CCL) composed of an insulator layer and a copper foil layer to form a non-linear complex electric circuit, and then protecting the circuit portion with an insulating layer. It is made through a process of attaching an adhesive part of a cover lay (CL) made of an adhesive layer to a circuit part.
The FFC is obtained by using a base material composed of an insulator layer and an adhesive layer and a conductor such as a copper foil formed in a wiring shape, and arranging and bonding a plurality of conductors between the adhesive parts of the base material. It is a linear electric circuit.
Accordingly, the coverlay in the FPC and the base material in the FFC are structurally the same.

  In consideration of properties such as heat resistance, dimensional stability, flexibility, high flexibility, and ease of thinning, the coverlay or base material is usually combined with various polyimide films and adhesives in the case of FPC. When the coverlay is FFC, usually a combination of various polyethylene terephthalate (hereinafter also referred to as PET) films and an adhesive is mainly used.

  In recent years, with an increase in the amount of information to be transmitted, there is an increasing demand for circuit boards for high frequency applications. In order to increase the amount of information to be transmitted, it is necessary to increase the frequency of the circuit. In this case, however, there is a problem that the transmission loss increases as the frequency increases. Since a circuit with a high transmission loss is not practical, it is necessary to reduce the transmission loss in order to efficiently transmit information in a higher frequency region than a conventional product.

Transmission loss can be reduced by lowering the dielectric constant of copper-clad laminates, coverlays, and FFC substrates in FPCs, so low dielectric constant copper-clad laminates, coverlays, and FFC substrates It has been demanded. In such a background, Patent Document 1 discloses a coverlay formed by bonding a polyimide film and a fluororesin as a coverlay that is excellent in workability at the time of manufacturing a high-frequency circuit board and has a low dielectric constant. ing.
However, the coverlay may not be sufficient in the adhesion between the polyimide film layer and the fluororesin layer after the high-temperature and high-humidity treatment. A coverlay was sought.

In addition, as a substrate for FFC, it is conceivable to develop a substrate suitable for a high-frequency circuit by a combination in which an insulating layer is a PET film and an adhesive layer is a fluorine resin. However, in this case, when a base material composed of an insulator layer and an adhesive layer is manufactured, or when an FFC is formed using the base material, a temperature equal to or higher than the melting point of the fluororesin layer that is the adhesive layer is the basis. Although the insulation layer PET film is insufficient in heat resistance at the temperature, a polymer film such as a polyimide film having heat resistance superior to that of a fluororesin is required as the insulation layer. It is done.
For this reason, although it is thought that the structure of the coverlay of patent document 1 is applicable also to the base material for high frequency circuit FFCs, also in this case, like the coverlay in FPC, It has been pointed out that the adhesion between the fluororesin layers may not be sufficient.
Therefore, a high-frequency circuit board cover lay and a flexible flat cable base material having excellent adhesion after treatment under high temperature and high humidity between the polyimide film layer and the fluororesin layer are desired.

Japanese Patent Application No. 2013-072570

  In view of the above situation, the present invention provides an FPC coverlay and an FFC base material in a high-frequency circuit using a polyimide film and a fluororesin that have excellent adhesion between the polyimide film layer and the fluororesin layer after being treated under high temperature and high humidity. The purpose is to provide.

That is, the present invention relates to the following coverlay or FFC base material.
[1] A base material for a coverlay or flexible flat cable (FFC) comprising a polyimide film layer and a fluororesin layer, after 96 hours in an 85 ° C. and 85 RH% environment between the polyimide film layer and the fluororesin layer The coverlay or the FFC base material is characterized in that the adhesion strength (moisture-resistant adhesion strength) is maintained at 50% or more with respect to the initial adhesion strength between the polyimide film layer and the fluororesin layer.
[2] The coverlay or FFC substrate according to [1] above, wherein the glass transition point of at least an arbitrary part of the polyimide film layer is 300 ° C. or lower.
[3] When the storage elastic modulus at 30 ° C. in at least an arbitrary part of the polyimide film layer is 100%, the storage elastic modulus at 300 ° C. is 50% or less [1] or [ [2] The coverlay or FFC substrate according to [2].
[4] When the loss elastic modulus at 30 ° C. in at least an arbitrary part of the polyimide film layer is 100%, the loss elastic modulus in the region of 30 to 300 ° C. has an apex that is 200% or more. The coverlay or FFC substrate according to any one of [1] to [3], which is characterized.
[5] The coverlay or FFC substrate according to any one of [1] to [4], wherein the fluororesin has a melting point of 200 ° C. or lower.
[6] The fluororesin is a fluorine-containing ethylenic polymer, and the fluorine-containing ethylenic polymer contains a carbonyl group, according to any one of the above [1] to [5] Coverlay or FFC substrate.
[7] The cover according to [6], wherein the content of carbonyl groups in the fluorine-containing ethylenic polymer is 3 to 1000 in total with respect to 1 × 10 ⁶ main chain carbon atoms. Ray or FFC substrate.
[8] Fluorine-containing fluorine-containing resin having at least one selected from the group consisting of a carbonate group, a carboxylic acid halide group, and a carboxylic acid group for a total of 3 to 1000 carbon atoms with respect to 1 × 10 ⁶ main chain carbon atoms The coverlay or FFC substrate according to any one of the above [1] to [5], comprising an ethylenic polymer.
[9] The fluororesin is tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, vinyl fluoride, hexafluoropropylene, hexafluoroisobutene, the following formula (X):
_{^{CH 2 = CR 1 (CF 2}} ) n R 2 (X)
(In the formula, R1 represents H or F, R2 represents H, F or Cl, and n represents a positive integer of 1 to 10.)
1 or more types of fluorine-containing ethylenic monomers selected from the group consisting of monomers represented by formula (2) and perfluoro (alkyl vinyl ethers) having 2 to 10 carbon atoms, or the fluorine-containing ethylenic monomers and carbon The coverlay or FFC group according to any one of [1] to [5] above, which is a fluorine-containing ethylenic polymer obtained by polymerizing an ethylenic monomer having a number of 5 or less Wood.
[10] The coverlay or FFC according to any one of [1] to [5], wherein the fluororesin is a copolymer obtained by polymerizing at least the following (a), (b) and (c): Substrate for use.
(A) Tetrafluoroethylene 20-90 mol%
(B) 10-80 mol% ethylene
(C) Formula CF ₂ = CFR ³ (Y)
(In the formula, R ³ represents CF ₃ or OR ⁴ , and R ⁴ represents a perfluoroalkyl group having 1 to 5 carbon atoms.)
1 to 70 mol% of a compound represented by

  The coverlay or FFC substrate of the present invention is industrially advantageous because it is excellent in moisture-resistant adhesion between the polyimide film layer and the fluororesin layer and can improve the workability during the production of the high-frequency circuit board. In addition, the high-frequency circuit board using the coverlay or FFC base material of the present invention has a low dielectric constant of fluororesin having a low dielectric constant, and can suppress transmission loss.

The coverlay or FFC base material of the present invention is a coverlay or FFC base material composed of a polyimide film layer and a fluororesin layer. The adhesive strength after 96 hours (moisture-resistant adhesive strength) is maintained at 50% or more of the initial adhesive strength between the polyimide film layer and the fluororesin layer.
In the present invention, “initial adhesion between the polyimide film layer and the fluororesin layer” is the coverlay or FFC substrate obtained by laminating or bonding the polyimide film and the fluororesin in an adhesive state. After processing FPC or FFC corresponding to FPC or FFC, for example, after manufacturing FPC or FFC, external factors such as heating and humidification other than the processing related to the processing are not loaded. It refers to the adhesion between the polyimide film layer and the fluororesin layer of the coverlay or FFC substrate in the present invention. When measuring the initial adhesion, it is preferable to measure within 24 hours after processing the sample, and particularly preferably within 12 hours.

  In producing a polyimide film used for the coverlay or FFC substrate, first, an aromatic diamine component and an acid anhydride component are polymerized in an organic solvent to obtain a polyamic acid solution.

Specific examples of the aromatic diamine component include paraphenylenediamine, metaphenylenediamine, benzidine, paraxylylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, 3,3′-dimethyl-4,4′-diaminodiphenylmethane, 1,5-diaminonaphthalene, 3,3′-dimethoxybenzidine, 1,4-bis (3methyl-5 Aminophenyl) benzene, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-bis (trifluoromethyl) -4,4 '-Diaminobiphenyl, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 9,9'- Bis (4-aminophenyl) fluorene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4, 4'-bis (aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, 2,2'-bis (4-aminophenoxyphenyl) propane, bis [4- (4-aminophenoxy) phenyl ] Sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 3,3′-dihydroxy-4,4′-diamino Biphenyl etc. are mentioned. These may be used singly or in combination of two or more.
The aromatic diamine component is preferably paraphenylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4- Aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4′-bis (aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 2,2′-bis (4-aminophenoxyphenyl) propane and the like, more preferably 4,4′-diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) benzene, 2,2′-bis (4-aminophenoxyphenyl) Propane and the like.

Specific examples of the acid anhydride component include pyromellitic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 2,3 ′, 3,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid, 2,3,6,7-naphthalenedicarboxylic acid,
Oxydiphthalic acid, 3,4,3 ′, 4′-biphenylsulfonetetracarboxylic acid, 4,4 ′-(2,2-hexafluoroisopropylidene) diphthalic acid, meta (para) -phenyl-3,4,3 Acid anhydrides such as 4'-tetracarboxylic acid, oxydiphthalic acid, 2,2-bis (3,4-dicarboxyphenyl) ether, pyridine-2,3,5,6-tetracarboxylic acid and amide-forming derivatives thereof Things. These may be used singly or in combination of two or more.
The acid anhydride component is preferably pyromellitic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, oxydiphthalic acid, 2,3 ′, 3,4′-biphenyltetracarboxylic acid, 3,3 ′. 4,4′-benzophenone tetracarboxylic acid, and more preferably pyromellitic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, oxydiphthalic acid, and the like.

  The raw materials for producing the polyimide film used for the coverlay or FFC substrate of the present invention are mainly paraphenylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,4-bis (4- Aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4′-bis (aminophenoxy) biphenyl, 4,4′-bis ( One or more aromatic diamine components selected from the group consisting of 3-aminophenoxy) biphenyl and 2,2′-bis (4-aminophenoxyphenyl) propane, pyromellitic acid, 3,3 ′, 4,4′- Biphenyltetracarboxylic acid, oxydiphthalic acid, 2,3 ′, 3,4′-biphenyltetracarboxylic acid, 3,3 , Those containing one or more acid anhydride component selected from the group consisting of 4,4'-benzophenone tetracarboxylic acid, preferably exemplified.

  In the present invention, examples of the organic solvent used for forming the polyamic acid solution include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, and formamide such as N, N-dimethylform and N, N-diethylformamide. Solvents, acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m- , Or a phenolic solvent such as p-cresol, xylenol, halogenated phenol, and catechol, or an aprotic polar solvent such as hexamethylphosphoramide and γ-butyrolactone. These may be used alone or in combination of two or more. Is preferably used as a mixture. Emissions, also aromatic hydrocarbons such as toluene can be used.

  The polymerization method is not particularly limited and may be carried out by any known method. For example, (1) the aromatic diamine component total amount is first put in a solvent, and then the acid anhydride component is converted into the aromatic diamine component total amount. A method of polymerizing by adding to an equivalent amount.

  (2) A method in which the entire amount of the acid anhydride component is first put in a solvent, and then the aromatic diamine component is added in an amount equivalent to the acid anhydride component for polymerization.

  (3) After putting one aromatic diamine component (a1) in a solvent, mixing for the time required for the reaction at a ratio of 95 to 105 mol% of one acid anhydride component (b1) with respect to the reaction component After that, the other aromatic diamine component (a2) is added, and then the other acid anhydride component (b2) is added so that the total aromatic diamine component and the total acid anhydride component are approximately equivalent. A method of adding and polymerizing.

  (4) After putting one acid anhydride component (b1) in a solvent, mixing for a time required for the reaction at a ratio of 95 to 105 mol% of one aromatic diamine component (a1) with respect to the reaction component After that, the other acid anhydride component (b2) is added, and then the other aromatic diamine component (a2) is added so that the total aromatic diamine component and the total acid anhydride component are approximately equivalent. And then polymerize.

  (5) A polyamic acid solution (A) is prepared by reacting one aromatic diamine component and an acid anhydride component in a solvent so that either one becomes excessive, and the other aromatic diamine component in another solvent. The polyamic acid solution (B) is prepared by reacting the acid anhydride component with either acid anhydride component, and the resulting polyamic acid solutions (A) and (B) are mixed to complete the polymerization. It is done. In the method of (5), when the aromatic diamine component is excessive in preparing the polyamic acid solution (A), the polyamic acid solution (B) has an excess of acid anhydride component and the polyamic acid solution (A). When the acid anhydride component is excessive, the polyamic acid solution (B) makes the aromatic diamine component excessive, mixes the polyamic acid solutions (A) and (B), and uses the total aromatic diamine component and acid used in these reactions. Adjust so that the anhydride component is approximately equivalent.

  The polymerization method is not limited to these, and other known methods may be used.

  The polyamic acid solution thus obtained usually contains 5 to 40% by weight of solid content, and preferably contains 10 to 30% by weight of solid content. The viscosity is usually 10 to 10000 Pa · s as measured by a Brookfield viscometer, and preferably 300 to 5000 Pa · s for stable liquid feeding. Moreover, the polyamic acid in the organic solvent solution may be partially imidized.

  Next, the manufacturing method of the polyimide film of this invention using the said polyamic acid solution is demonstrated.

  As a method for forming a polyimide film, a polyamic acid solution is cast into a film and thermally decyclized and desolvated to obtain a polyimide film, and a polyamic acid solution is mixed with a cyclization catalyst and a dehydrating agent. A method of obtaining a polyimide film by producing a gel film by thermally decyclizing and desolvating it by heating is mentioned.

  The polyamic acid solution may contain a cyclization catalyst (imidization catalyst), a dehydrating agent, a gelation retarder, and the like.

  Specific examples of the cyclization catalyst used in the present invention include aliphatic tertiary amines such as trimethylamine and triethylenediamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic rings such as isoquinoline, pyridine and betapicoline. Although a tertiary amine etc. are mentioned, a heterocyclic tertiary amine is preferable. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  Specific examples of the dehydrating agent used in the present invention include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride and butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride. Acetic anhydride and / or benzoic anhydride are preferred.

  As a method for producing a polyimide film from a polyamic acid solution, a polyamic acid solution containing the cyclization catalyst and the dehydrating agent is cast from a slit-attached base onto a support, and is molded into a film. Examples of the method include a method in which imidization is partially advanced to form a gel film having self-supporting property, and then peeled from the support, heat-dried / imidized, and heat-treated.

  The support is a metal rotating drum or endless belt, and its temperature is controlled by a liquid or gaseous heat medium and / or by radiant heat from an electric heater or the like.

  The gel film is usually heated to 30 to 200 ° C., preferably 40 to 150 ° C. by receiving heat from the support and / or receiving heat from a heat source such as hot air or an electric heater, and a ring-closing reaction is performed. By drying the volatile matter, it becomes self-supporting and is peeled off from the support.

  The gel film peeled off from the support may be stretched in the traveling direction while regulating the traveling speed with a rotating roll, if necessary. The draw ratio (MDX) in the machine conveyance direction and the draw ratio (TDX) in the direction perpendicular to the machine conveyance direction are 1.01 to 3.0 times, preferably 1.05 to 2.0 times. The

  The film dried in the drying zone is heated for 15 seconds to 10 minutes with hot air, an infrared heater or the like. Next, heat treatment is performed at a temperature of 250 to 500 ° C. for 15 seconds to 20 minutes with hot air and / or an electric heater.

  Moreover, although the running speed is adjusted and the thickness of a polyimide film is adjusted, as a thickness of a polyimide film, it is about 2-250 micrometers normally, and about 2-100 micrometers is preferable. If it is thinner or thicker than this, the film-forming property of the film is remarkably deteriorated.

  A commercially available product may be used as the polyimide film used in the present invention. Although it does not specifically limit as a commercial item, For example, EN type (For example, 50EN-S (brand name, the Toray DuPont company make), 100EN (brand name, the Toray DuPont company make) etc.) etc. of Kapton, Kapton H type (for example, Kapton 100H (trade name, manufactured by Toray DuPont), etc.), Kapton KJ type (for example, Kapton 100KJ (trade name, manufactured by DuPont, USA)), Kapton JP type (for example, Kapton) 100JP (trade name, manufactured by DuPont, USA) and the like.

  The polyimide film in the present invention may contain a plasticizer, other resin and the like as long as the object of the present invention is not impaired.

  The plasticizer is not particularly limited, and examples thereof include bisphenol compounds such as hexylene glycol, glycerin, β-naphthol, dibenzylphenol, octylcresol, bisphenol A, octyl p-hydroxybenzoate, p-hydroxybenzoic acid- 2-ethylhexyl, p-hydroxy p-hydroxybenzoate, ethylene oxide and / or propylene oxide adducts of p-hydroxybenzoic acid, ε-caprolactone, phosphate compounds of phenols, N-methylbenzenesulfonamide, N-ethylbenzenesulfone Examples include amide, N-butylbenzenesulfonamide, toluenesulfonamide, N-ethyltoluenesulfonamide, N-cyclohexyltoluenesulfonamide, and the like.

  As said other resin mix | blended with a polyimide, what is excellent in compatibility is preferable, for example, ester and / or carboxylic acid modified olefin resin, acrylic resin (especially acrylic resin which has a glutarimide group), ionomer resin, polyester resin , Phenoxy resin, ethylene-propylene-diene copolymer, polyphenylene oxide and the like.

  The polyimide film in the present invention may contain a colorant, various additives and the like as long as the object of the present invention is not impaired. Examples of the additive include an antistatic agent, a flame retardant, a heat stabilizer, an ultraviolet absorber, a lubricant, a mold release agent, a crystal nucleating agent, and a reinforcing agent (filler). The polyimide film surface may be coated with ink or the like.

  In the present invention, a polyimide film or a polyimide film partially containing polyamic acid is introduced as a binder between the polyimide film layer and the fluororesin layer, and a multilayer polyimide layer of a polyimide layer and a binder layer as a base material is formed. You can also The polyamic acid used in producing the polyimide film used for the binder layer is the diamine described in [0013] and the acid anhydride described in [0014], for example, using the method described in [0017] to [0023]. Can be obtained by polycondensation. The method for forming the multilayer polyimide layer is not particularly specified, but the polyamic acid of the binder layer obtained by polycondensation is changed to a polyimide film by the method described in [0025] to [0039], and then the polyimide film is used as a base material. A method of bonding with a polyimide film to be used, a method of applying a polyamic acid of a binder layer on a polyimide film to be a base material, and partially or entirely drying it chemically or thermally, and a polyimide to be a base material It can be obtained by a method in which a film layer, a binder layer, or a fluororesin layer is bonded at a time.

The polyimide film used in the present invention preferably has at least an arbitrary glass transition point of 300 ° C. or lower. In addition, the polyimide film used in the present invention preferably has a storage elastic modulus at 300 ° C. of 50% or less when the storage elastic modulus at 30 ° C. of at least an arbitrary part is 100%, and 40% or less. More preferably, it is more preferably 30% or less.
In addition, the polyimide film used in the present invention has an apex at which the loss elastic modulus in the region of 30 to 300 ° C. is a value of 200% or more when the loss elastic modulus at 30 ° C. in at least an arbitrary part is 100%. It is preferable to have it. The “at least an arbitrary part” means a longitudinal conveyance direction (hereinafter also referred to as MD) in the process of producing a film, a direction perpendicular to the MD direction (hereinafter also referred to as TD direction), and further from the TD direction. The direction inclined at an arbitrary angle, the portion corresponding to the sample length in each).

  Although the fluororesin used for the coverlay or FFC substrate of the present invention is not particularly limited, a fluorine-containing ethylenic polymer is preferable. The fluorinated ethylenic polymer in the present invention is one in which a carbonyl group or a carbonyl group-containing functional group is bonded to a fluorinated ethylenic polymer chain.

  The “carbonyl group” refers to a functional group having —C (═O) — that can basically react with an imide group or an amino group in a polyimide film. Specific examples include carbonates, carboxylic acid halides, aldehydes, ketones, carboxylic acids, esters, acid anhydrides, and isocyanate groups. The carbonyl group is not particularly limited, but a carbonate group, a carboxylic acid halide group, a carboxylic acid group, an ester group, and an acid anhydride group are preferable because they can be easily introduced and have high reactivity with a polyamide-based resin. More preferred are carbonate groups and carboxylic acid halide groups.

The number of carbonyl groups in the fluorine-containing ethylenic polymer in the present invention is the type, shape, purpose of adhesion, use, required adhesive strength of the laminated material, the form of the polymer and the adhesion method, etc. Although it may be appropriately selected depending on the difference, the number of carbonyl groups is preferably 3 to 1000 in total with respect to 1 × 10 ⁶ main chain carbon atoms. If the number of carbonyl groups is less than 3 with respect to 1 × 10 ⁶ main chain carbon atoms, sufficient adhesive strength may not be exhibited. On the other hand, when the number exceeds 1,000, the adhesive force may be lowered due to a chemical change of the carbonyl group in accordance with the bonding operation. The number is more preferably 3 to 500, still more preferably 3 to 300, and particularly preferably 5 to 150. In addition, content of the carbonyl group in a fluorine-containing ethylenic polymer can be measured by infrared absorption spectrum analysis.

Therefore, when the fluorine-containing ethylenic polymer of the present invention has, for example, a carbonate group and / or a carboxylic acid halide group, and has a carbonate group, the number of carbonate groups is 1 × 10 ⁶ carbon atoms in the main chain. The number is preferably 3 to 1000. Moreover, when the fluorine-containing ethylenic polymer of this invention has a carboxylic acid halide group, it is preferable that the number of the carboxylic acid halide group is 3-1000 with respect to 1 * 10 < ⁶ > main chain carbon number. When the fluorine-containing ethylenic polymer of the present invention has both carbonate groups and carboxylic acid halide groups, the total number of carbonate groups and carboxylic acid halide groups is 3 to 1000 with respect to 1 × 10 ⁶ main chain carbon atoms. Are preferred. If the number of carbonate groups and / or carboxylic acid halide groups is less than 3 with respect to 1 × 10 ⁶ main chain carbon atoms, sufficient adhesive strength may not be exhibited. On the other hand, when the number exceeds 1,000, the generation of gas that appears at the bonding interface due to the chemical change of the carbonate group or the carboxylic acid halide group may be adversely affected and the adhesive force may be reduced. From the viewpoint of heat resistance and chemical resistance, the number is more preferably 3 to 500, still more preferably 3 to 300, and particularly preferably 5 to 150. In addition, 10 or more, more preferably 20 or more carboxylic acid halide groups having excellent reactivity with the polyamide-based resin are present in the fluorine-containing ethylenic polymer with respect to 1 × 10 ⁶ main chain carbon atoms. If this is the case, even if the total carbonyl group content is less than 150 with respect to 1 × 10 ⁶ carbon atoms in the main chain, excellent adhesion to the polyamide resin layer (A) can be exhibited. Can do.

The carbonate group in the fluorine-containing ethylenic polymer in the present invention is generally a group having a bond of —OC (═O) O—, specifically, a —OC (═O) O—R group [R the organic group _(e.g., C 1 _{-C 20} alkyl group (preferably _C 1 _{-C 10} alkyl group), _C 2 _{-C 20} alkyl group having an ether bond) or VII group element. ] Of the structure. The carbonate group, for _{example, -OC (= O) OCH 3} , -OC (= O) OC 3 H 7, -OC (= O) OC 8 H 17, -OC (= O) OCH 2 CH 2 CH 2 Preferred examples include OCH ₂ CH _{3 and the} like.

  The carboxylic acid halide group in the fluorine-containing ethylenic polymer in the present invention specifically has a structure of —COY [Y is a halogen element], and examples thereof include —COF and —COCl.

  The fluorine-containing ethylenic polymer having these carbonyl groups can maintain the excellent characteristics of the fluorine-containing resin itself, reducing the excellent characteristics of the fluorine-containing resin in the laminate after molding. Can be given without.

  The fluorine-containing ethylenic polymer in the present invention contains a carbonyl group in the polymer chain, but the embodiment in which the carbonyl group is contained in the polymer chain is not particularly limited, for example, a carbonyl group or a functional group containing a carbonyl group May be bonded to the polymer chain end or side chain. Among them, those having a carbonyl group at the end of the polymer chain are preferable because they do not significantly reduce heat resistance, mechanical properties and chemical resistance, or are advantageous in terms of productivity and cost. Among these, a method of introducing a carbonyl group at the end of a polymer chain using a polymerization initiator containing a carbonyl group such as peroxycarbonate or peroxyester or having a functional group that can be converted into a carbonyl group is introduced. This is a preferred embodiment because it is very easy and the amount of introduction can be easily controlled. In the present invention, the carbonyl group derived from peroxide refers to a carbonyl group derived directly or indirectly from a functional group contained in the peroxide.

In addition, in the fluorine-containing ethylenic polymer in the present invention, even if a fluorine-containing ethylenic polymer not containing a carbonyl group is present, the total amount of the polymer as described above is 1 × 10 ⁶ main chain carbons. It is sufficient that the number of carbonyl groups is within the range.

  In the present invention, the type and structure of the fluorine-containing ethylenic polymer can be appropriately selected depending on the purpose, application, and method of use, and the melting point is preferably 160 to 270 ° C. Such a polymer is advantageous, especially when laminating by heating and melt-bonding, since it can sufficiently exert the adhesiveness between the carbonyl group and the counterpart material, and can give a strong adhesive force directly to the counterpart material. is there. The melting point is more preferably 250 ° C. or less, further preferably 230 ° C. or less, and particularly preferably 200 ° C. or less in that lamination with an organic material having relatively low heat resistance is possible. The melting point was recorded as the melting peak when the temperature was raised at a rate of 10 ° C./min using a Seiko DSC apparatus (manufactured by Seiko Denshi), and the temperature corresponding to the maximum value was defined as the melting point (Tm).

  Regarding the molecular weight of the fluorinated ethylenic polymer in the present invention, the polymer can be molded at a temperature lower than the thermal decomposition temperature, and the obtained molded product can express the original excellent mechanical properties and the like of the fluorinated ethylenic polymer. It is preferable that it is a range. Specifically, with the melt flow rate (MFR) as the molecular weight index, the MFR at an arbitrary temperature in the range of about 230 to 350 ° C., which is a general molding temperature range of fluororesin, is 0.5 to 100 g / 10 min. It is preferable. MFR uses a melt indexer (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the weight of the polymer flowing out in a unit time (10 minutes) from a nozzle having a diameter of 2 mm and a length of 8 mm under various temperatures and 5 kg load (g) Was measured.

  The structure of the fluorine-containing ethylenic polymer chain is generally a homopolymer chain or a copolymer chain having a repeating unit derived from at least one fluorine-containing ethylenic monomer, and only the fluorine-containing ethylenic monomer, Alternatively, it may be a polymer chain obtained by polymerizing a fluorine-containing ethylenic monomer and an ethylenic monomer having no fluorine atom.

The fluorine-containing ethylenic monomer is an olefinically unsaturated monomer having a fluorine atom, specifically, tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, vinyl fluoride, hexafluoropropylene, Hexafluoroisobutene, formula (X):
CH ₂ = CR ¹ (CF ₂ ) nR ² (X)
(In the formula, R ₁ represents H or F, R ² represents H, F or Cl, and n represents a positive integer of 1 to 10.)
And perfluoro (alkyl vinyl ether) s having 2 to 10 carbon atoms.

  The ethylenic monomer having no fluorine atom is preferably selected from ethylenic monomers having 5 or less carbon atoms in order not to lower the heat resistance and the like. Specific examples include ethylene, propylene, 1-butene, 2-butene, vinyl chloride, vinylidene chloride and the like.

  When a fluorine-containing ethylenic monomer and an ethylenic monomer having no fluorine atom are used, the monomer composition is 10 mol% or more and less than 100 mol% (for example, 30 mol%). The molar ratio may be greater than 0 mol% and less than 90 mol% (for example, greater than 0 mol% and less than 70 mol%).

  In the fluorine-containing ethylenic polymer in the present invention, the melting point or glass transition of the polymer can be selected by selecting the type, combination, composition ratio, etc. of the fluorine-containing ethylenic monomer and the ethylenic monomer having no fluorine atom. The point can be adjusted.

  As the fluorine-containing ethylenic polymer in the present invention, in terms of heat resistance and chemical resistance, a carbonyl group-containing fluorine-containing ethylenic polymer having a tetrafluoroethylene unit as an essential component is preferable, and in terms of molding processability. Then, a carbonyl group-containing fluorine-containing ethylenic copolymer having a vinylidene fluoride unit as an essential component is preferable.

Preferable specific examples of the fluorine-containing ethylenic polymer in the present invention include a carbonyl group-containing fluorine-containing ethylenic copolymer (I), which is obtained by essentially polymerizing the following monomers. (V) and the like can be mentioned:
(I) a copolymer obtained by polymerizing at least tetrafluoroethylene and ethylene,
(II) At least tetrafluoroethylene and the following formula (Y):
CF ₂ = CFR ³ (Y)
(In the formula, R ³ represents CF ₃ or OR ⁴ , and R ⁴ represents a perfluoroalkyl group having 1 to 5 carbon atoms.)
A copolymer obtained by polymerizing a compound represented by
(III) a copolymer obtained by polymerizing at least vinylidene fluoride,
(IV) a copolymer obtained by polymerizing at least the following (a), (b) and (c):
(A) Tetrafluoroethylene 20-90 mol%
(B) 10-80 mol% ethylene
(C) CF ₂ = CFR ³ (Y)
(Wherein R ³ represents the same meaning as described above.)
1 to 70 mol% of the compound represented by:
(V) A copolymer obtained by polymerizing at least the following (d), (e) and (f).
(D) 15-60 mol% vinylidene fluoride
(E) Tetrafluoroethylene 35-80 mol%
(F) 5-30 mol% hexafluoropropylene
In these specific examples, other known monomers may be added as long as they contain the aforementioned monomers and do not impair the effects of the present invention.

  All of these exemplified carbonyl group-containing fluorine-containing ethylenic polymers are particularly preferable in terms of excellent heat resistance.

  As said copolymer (I), tetrafluoroethylene unit 20-90 mol% with respect to the whole monomer except the monomer which has a carbonyl group (when it has a carbonyl group containing functional group in a side chain), for example (For example, 20 to 60 mol%), 10 to 80 mol% (for example, 20 to 60 mol%) of ethylene units, and 0 to 70 mol% of other monomer units copolymerizable therewith. And a containing copolymer.

Examples of the other copolymerizable monomer include hexafluoropropylene, chlorotrifluoroethylene, and formula (X):
^{_{CH 2 = CR 1 (CF 2}} ) n R 2 (X)
(In the formula, R1 represents H or F, R2 represents H, F or Cl, and n represents a positive integer of 1 to 10.)
, C2-C10 perfluoro (alkyl vinyl ether) s, propylene, and the like, and usually one or more of these are used.

Further, as the copolymer (I), for example, the following can maintain the excellent performance of the tetrafluoroethylene / ethylene copolymer, can have a relatively low melting point, and can adhere to other materials. It is preferably mentioned in that it can exhibit the maximum properties.
(I-1) a carbonyl group-containing copolymer of a polymer chain comprising 62 to 80 mol% of tetrafluoroethylene units, 20 to 38 mol% of ethylene units, and 0 to 10 mol% of other monomer units,
(I-2) Polymer chain carbonyl comprising 20 to 80 mol% tetrafluoroethylene units, 10 to 80 mol% ethylene units, 0 to 30 mol% hexafluoropropylene units, and 0 to 10 mol% other monomer units Group-containing copolymer.

As said copolymer (II), the following are mentioned suitably, for example.
(II-1) containing a carbonyl group in a polymer chain composed of 65 to 95 mol% (preferably 75 to 95 mol%) tetrafluoroethylene units and 5 to 35 mol% (preferably 5 to 25 mol%) hexafluoropropylene units Copolymer,
(II-2) tetrafluoroethylene units 70 to 97 ^{_{mol%, CF 2 = CFOR 4 (}} R 4 is a perfluoroalkyl group having 1 to 5 carbon atoms) copolymer containing carbonyl groups in the polymer chain of 3 to 30 mole percent Polymer,
(II-3) a copolymer having a carbonyl group of a polymer chain comprising a tetrafluoroethylene unit, a hexafluoropropylene unit, and a CF ₂ ═CFOR ⁴ (R ⁴ is the same as above) unit, A copolymer in which the total of CF ₂ = CFOR ⁴ units is 5 to 30 mol%.

  Said (II-1)-(II-3) is also a perfluoro-type copolymer, and is the most excellent in heat resistance, electrical insulation, etc. among a fluorine-containing polymer.

Examples of the copolymer (III) include vinylidene fluoride units of 15 to 99 mol with respect to the whole monomer excluding the monomer having a carbonyl group (when the side chain has a carbonyl group-containing functional group). %, A carbonyl group-containing copolymer of a polymer chain composed of 0 to 30 mol% of tetrafluoroethylene units and 0 to 30 mol% of one or more units of hexafluoropropylene or chlorotrifluoroethylene.
Specific examples of the copolymer (III) include the following.
(III-1) a carbonyl group-containing copolymer of a polymer chain comprising 30 to 99 mol% of vinylidene fluoride units and 1 to 70 mol% of tetrafluoroethylene units,
(III-2) a carbonyl group-containing copolymer of a polymer chain comprising vinylidene fluoride units 60 to 90 mol%, tetrafluoroethylene units 0 to 30 mol%, chlorotrifluoroethylene units 1 to 20 mol%,
(III-3) a carbonyl group-containing copolymer of a polymer chain comprising 60 to 99 mol% of vinylidene fluoride units, 0 to 30 mol% of tetrafluoroethylene units, and 5 to 30 mol% of hexafluoropropylene units,
(III-4) A carbonyl group-containing copolymer of a polymer chain comprising 15 to 60 mol% of vinylidene fluoride units, 35 to 80 mol% of tetrafluoroethylene units, and 5 to 30 mol% of hexafluoropropylene units.

  It does not specifically limit as a manufacturing method of the fluorine-containing ethylenic polymer in this invention. The fluorine-containing ethylenic polymer of the present invention is obtained by copolymerizing an ethylenic monomer having a carbonyl group with a fluorine-containing and / or ethylenic monomer of a type and blended with the target fluorine-containing polymer. Can be manufactured. The ethylenic monomer having a carbonyl group is preferably perfluoroacrylic acid (fluoride), 1-fluoroacrylic acid (fluoride), acrylic acid fluoride, 1-trifluoromethacrylic acid (fluoride), perfluoro. Fluorine-containing monomers such as butenoic acid; monomers not containing fluorine, such as acrylic acid, methacrylic acid, acrylic acid chloride, vinylene carbonate, itaconic acid, citraconic acid, and the like.

  On the other hand, in order to obtain a fluorine-containing ethylenic polymer having a carbonyl group at the polymer molecule end, various methods can be employed, but peroxides, particularly peroxycarbonates and peroxyesters are used as polymerization initiators. The method can be preferably employed in terms of quality such as economy, heat resistance and chemical resistance. According to this method, a carbonyl group derived from peroxide (for example, a carbonate group derived from peroxycarbonate; an ester group derived from peroxyester; or a carboxylic acid halide group obtained by converting these functional groups Alternatively, carboxylic acid groups) can be introduced at the polymer chain ends. Among these polymerization initiators, when peroxycarbonate is used, the polymerization temperature can be lowered, and it is more preferable because no side reaction is involved in the initiation reaction.

Examples of the peroxycarbonate include the following formulas (1) to (4):
[In the formula, R and Ra are linear or branched monovalent saturated hydrocarbon groups having 1 to 15 carbon atoms, or linear or branched groups having 1 to 15 carbon atoms containing an alkoxy group at the terminal. Represents a monovalent saturated hydrocarbon group, and Rb is a linear or branched divalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a linear or branched chain having 1 to 15 carbon atoms containing an alkoxy group at the end, or A branched divalent saturated hydrocarbon group is represented. ]
The compound etc. which are represented by these are mentioned suitably. In particular, diisopropyl peroxycarbonate, di-n-propyl peroxydicarbonate, t-butyl peroxyisopropyl carbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, etc. preferable.

  The amount of initiator used such as peroxycarbonate and peroxyester varies depending on the type of polymer (composition, etc.), the molecular weight, the polymerization conditions, and the type of initiator used. It is 0.05-20 weight part normally with respect to a weight part, and it is especially preferable that it is 0.1-10 weight part.

As the polymerization method, suspension polymerization in an aqueous medium using a fluorine-based solvent industrially and using peroxycarbonate or the like as a polymerization initiator is preferable, but other polymerization methods such as solution polymerization and emulsion polymerization are preferable. Also, bulk polymerization and the like can be employed. In suspension polymerization, a fluorinated solvent may be used in addition to water. Examples of the fluorine-based solvent used for suspension polymerization include hydrochlorofluoroalkanes (for example, CH ₃ CClF ₂ , CH ₃ CCl ₂ F, CF ₃ CF ₂ CCl ₂ H, CF ₂ ClCF ₂ CFHCl), and chlorofluoroalkanes. class _{(e.g., CF 2 ClCFClCF 2 CF 3,} CF 3 CFClCFClCF 3), perfluoroalkanes (e.g., _{perfluorocyclobutane, CF 3 CF 2 CF 2 CF} 3, CF 3 CF 2 CF 2 CF 2 CF 3, CF 3 CF ₂ CF ₂ CF ₂ CF ₂ CF ₃ ) can be used, and perfluoroalkanes are preferred. The amount of the fluorine solvent to be used is not particularly limited, but in the case of suspension polymerization, it is preferably 10 to 100% by weight with respect to the aqueous medium from the viewpoint of suspension and economy.

  The polymerization temperature is not particularly limited, and may be 0 to 100 ° C. The polymerization pressure is appropriately determined according to other polymerization conditions such as the type, amount and vapor pressure of the solvent used, and the polymerization temperature, but may be 0 to 9.8 MPaG.

  A known chain transfer agent can be used for adjusting the molecular weight. Examples of the chain transfer agent include hydrocarbons such as isopentane, n-pentane, n-hexane, and cyclohexane; alcohols such as methanol and ethanol; halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride, and methyl chloride. be able to. The content of the terminal carbonate group or ester group can be controlled by adjusting the polymerization conditions, and can be controlled by the amount of peroxycarbonate or peroxyester used, the amount of chain transfer agent used, the polymerization temperature, or the like.

  In order to obtain a fluorinated ethylenic polymer having a carboxylic acid halide group or a carboxylic acid group at the polymer molecule end, various methods can be employed. For example, the fluorinated ethylenic polymer having the above-mentioned carbonate group or ester group at the end can be adopted. The coalescence can be obtained by heating and pyrolysis (decarboxylation). The heating temperature varies depending on the type of carbonate group or ester group and the type of fluorine-containing ethylenic polymer, but is usually 270 ° C or higher, preferably 280 ° C or higher, and particularly preferably 300 ° C or higher. Moreover, it is preferable to make heating temperature below the thermal decomposition temperature of parts other than the carbonate group or ester group of a fluorine-containing ethylenic polymer, specifically 400 degrees C or less is preferable, and 350 degrees C or less is more preferable.

<Method for measuring the number of carbonate groups>
The obtained white powder of the fluoroethylenic polymer or a cut piece of the melt-extruded pellet was compression molded at room temperature to produce a uniform film having a thickness of 0.05 to 0.2 mm. According to infrared absorption spectrum analysis of this film, a peak derived from a carbonyl group of a carbonate group (—OC (═O) O—) appears at an absorption wavelength of 1809 cm ⁻¹ (ν _C═O ), and its ν _C═O The absorbance of the peak was measured. The number (N) of carbonate groups per 10 ⁶ main chain carbon atoms was calculated by the following formula (5).
N = 500 AW / εdf (5)
A: Absorbance of ν _{C = O} peak of carbonate group (—OC (═O) O—) ε: Molar absorbance coefficient of ν _{C = O} peak of carbonate group (—OC (═O) O—) [l · cm ⁻¹ · mol ⁻¹ ]. Ε = 170 from the model compound.
W: Average molecular weight of monomer calculated from monomer composition d: Film density [g / cm ³ ]
f: Film thickness [mm]
The infrared absorption spectrum analysis was performed by scanning 40 times using a Perkin-Elmer FTIR spectrometer 1760X (manufactured by PerkinElmer). The obtained IR spectrum was analyzed using Perkin-Elmer Spectrum for Windows (registered trademark) Ver. The baseline was automatically determined at 1.4 C, and the absorbance of the peak at 1809 cm ⁻¹ was measured. The film thickness was measured with a micrometer.

<Method for measuring the number of carboxylic acid fluoride groups>
A peak derived from the carbonyl group of the carboxylic acid fluoride group (—C (═O) F) was found to be 1880 cm ⁻¹ (ν) by infrared spectrum analysis of the film obtained in the same manner as in the above method for measuring the number of carbonate groups. The absorbance at the ν _C═O peak appears at the absorption wavelength of _{C═O 2} ). Except that the molar absorbance coefficient [l · cm ⁻¹ · mol ⁻¹ ] of the ν _C═O peak of the carboxylic acid fluoride group was set to ε = 600 by the model compound, The number of carboxylic acid fluoride groups was measured in the same manner as the number measurement method.

<Measurement method of the number of other carbonyl groups>
Functional groups such as amide groups and amino groups in polyamide-based resins such as carboxylic acid groups, ester groups, and acid anhydride groups by infrared spectrum analysis of the film obtained in the same manner as the method for measuring the number of carbonate groups. The number of other carbonyl groups that can basically react with can also be measured. However, except that the molar absorbance coefficient [l · cm ⁻¹ · mol ⁻¹ ] of the ν _C═O peak derived from these carbonyl groups is ε = 530, the above carbonate group is obtained using the above formula (5). The number of other carbonyl groups was measured in the same manner as the method for measuring the number of carbonyl groups.

<Method for measuring composition of fluorine-containing ethylenic polymer>
^It was measured by ¹⁹ F-NMR analysis.

  The fluorine-containing ethylenic polymer in the present invention is preferably used alone because it does not impair the adhesiveness, heat resistance, chemical resistance, etc. of itself, but it does not impair the performance depending on the purpose and application. Thus, various known fillers such as inorganic powder, glass fiber, carbon fiber, metal oxide or carbon can be blended. In addition to the filler, a pigment, an ultraviolet absorber, and other optional additives can be mixed. In addition to additives, other fluororesins, thermoplastic resins, thermosetting resins, etc., synthetic rubber, etc. can also be blended, improving mechanical properties, improving weather resistance, imparting design, and preventing static electricity It becomes possible to improve moldability.

In addition, the fluorine-containing ethylenic polymer in the present invention itself has adhesiveness as described above, but for the purpose of further improving the adhesiveness, the fluorine-containing ethylenic polymer and its molded body ( For example, by applying surface treatment such as corona treatment, plasma treatment, electron beam irradiation treatment, sputtering treatment, coating treatment to films, etc., control of surface free energy or introduction of adhesive functional groups, adjustment of surface roughness May be performed. Conventionally known methods can be used for these treatments.
In corona treatment, plasma treatment, and electron beam irradiation treatment, fine irregularities are formed by the etching effect generated on the film surface by passing the film through the discharge atmosphere, thereby improving the adhesion area and the adhesion effect by the anchor effect. . In addition, in these treatments, the surface free energy can be controlled by introducing oxygen and hydrogen into the discharge atmosphere. For example, by using a fluorine-containing ethylenic polymer into which acrylic acid is introduced, a carboxyl group or the like is added to the film surface. Adhesive functional groups can also be formed.
In the sputtering process, the surface roughness is adjusted by the etching effect, and the reaction is activated and the adhesion is improved by cutting the molecular chain.
By forming a resin having adhesiveness dissolved in an organic solvent on the surface of the fluorinated ethylenic polymer by a coating treatment, the adhesiveness can be improved. Adhesive resin can be selected appropriately depending on the adherend, but if the wetness to the fluorine-containing ethylenic polymer surface is insufficiently repelled or peeled off, combine it with the above surface treatment. You can also.

  The coverlay or FFC substrate of the present invention has excellent moisture-resistant adhesion by combining the polyimide film and the fluororesin, and has sufficient adhesive strength. The coverlay or FFC substrate of the present invention is formed by laminating or bonding at least the polyimide film and the fluororesin in an adhesive state.

  The coverlay or FFC substrate of the present invention preferably has a thermal expansion coefficient of less than ± 0.1% at 260 ° C. for 30 minutes.

<Coverlay or FFC base material>
For the production of the coverlay or FFC substrate of the present invention, a production method in which a constituent layer containing the polyimide film precursor (polyamic acid solution) and the fluororesin is sequentially or coextruded; polyimide film and fluorine Production method of thermocompression bonding each molded product of resin; on the molded product of either polyimide film or fluororesin, the precursor of the other resin or melted one is applied and cast to obtain a resin composition A manufacturing method such as a manufacturing method for performing the treatment can be applied, and a good adhesion state between the constituent layers containing the polyimide film and the fluororesin is formed. The said manufacture can use the well-known molding machine of the thermoplastic resin used normally, for example, an injection molding machine, a compression molding machine, a blow molding machine, an extrusion molding machine, etc.

  The molding conditions differ depending on the type of carbonyl group, particularly carbonate group, and the type of fluorine-containing ethylenic polymer. However, in extrusion or blow molding, it is appropriate to heat the cylinder so that the cylinder temperature is 200 ° C or higher. is there. The heating temperature is preferably not more than a temperature at which adverse effects such as foaming due to thermal decomposition of the fluorine-containing ethylenic polymer itself can be suppressed, specifically 400 ° C. or less, more preferably 350 ° C. or less.

  Although it does not specifically limit as a manufacturing method by the said thermocompression bonding, For example, a vacuum press, a lamination method (thermal laminating method etc.), and a coating method are mentioned. The fluororesin layer may be laminated or coated on one or both sides of the polyimide film.

  In the vacuum press, for example, a cover lay or an FFC substrate is obtained by heat-pressing a polyimide resin and a fluororesin at a predetermined temperature and pressure using a known vacuum press. The press temperature at this time is preferably in the range of 100 to 250 ° C. from the viewpoint of easy processing. Further, annealing may be performed after pressing, and the annealing temperature is preferably in the range of 100 to 250 ° C. The heating time and pressure are not particularly limited, and can be appropriately set as necessary.

  In the heat laminating method, there is no particular limitation. For example, using two rollers that can be heated and the distance between the rollers can be arbitrarily adjusted, two or more kinds of films are stacked between the rollers, and heat and pressure are set. A coverlay or an FFC substrate is obtained by pressure bonding while applying. Moreover, it is also possible to perform heat processing continuously immediately after performing lamination as needed. The treatment is preferably in the range from the glass transition temperature (Tg) of the fluororesin to the melting point + 50 ° C. because the adhesion can be improved. Below Tg, the desired adhesion cannot be obtained, and when the melting point is + 50 ° C. or more, decomposition of the fluororesin starts and the adhesion decreases, which is not preferable. The heating time and pressure are not particularly limited, and can be appropriately set as necessary. The said apparatus is not specifically limited unless the effect of this invention is prevented.

  Prior to processing as FPC or FFC, the adhesive strength between the polyimide film layer and fluororesin layer of the coverlay or FFC substrate of the present invention is 3.0N in terms of accuracy in alignment and increased work efficiency. / N, more preferably 5.0 N / cm or more, and even more preferably 8.0 N / cm or more. The upper limit value of the adhesive strength is not particularly limited.

  The thickness of the polyimide film layer of the present invention is not particularly limited, but it affects the adhesion between the polyimide film layer of the coverlay or FFC substrate and the fluororesin layer, so that the thickness of the fluororesin layer is 0.01. About -2.0 times are preferable, About 0.05-1.0 times are more preferable, About 0.1-0.9 times are further more preferable. When the thickness of the polyimide layer exceeds 2.0 times, the rigidity and dimensional stability as a substrate are improved, but the dielectric constant increases, which is not preferable. If it is less than 0.01 times, the rigidity of the polyimide layer decreases and the linear expansion coefficient tends to increase, and the rigidity and dimensional stability as a substrate decrease.

  The base material for coverlay or FFC of the present invention has a heat shrinkage rate measured at 260 ° C. for 30 minutes of usually less than ± 0.1%, preferably less than ± 0.08%, more preferably ± It is less than 0.06%. The heat shrinkage rate is 12 hours or more under constant temperature and high humidity after being heat-treated for 30 minutes after being put into a sample before heat treatment and an oven set at 260 ° C. using a CNC image processing system NEXIV VM-250 manufactured by Nikon Corporation. The dimension of the conditioned sample (sample after heat treatment) was measured, and the percentage of the dimensional change rate before and after the heat treatment was defined as the heat shrinkage rate.

  The coverlay or FFC substrate of the present invention can be variously processed to produce a high-frequency circuit board as FPC or FFC. The manufacturing method of a high frequency circuit board is not specifically limited, It can manufacture by a well-known method.

<FPC>
FPC can be manufactured by bonding the coverlay of the present invention and a copper clad laminate. Examples of the method for producing the copper-clad laminate include a three-layer CCL in which a base film and a copper foil are laminated via an adhesive, and a copper layer using vapor deposition, sputtering, and electroplating on the base film. , A so-called cast type two-layer CCL (COC) formed by casting a polyimide layer on a copper foil, and a base film formed by forming a copper layer using electroless plating.

  Examples of the base film include polyimide films and LCP films for high-frequency circuits. Examples of the adhesive layer include epoxy-based, acrylic-based, polyimide-based adhesive, and fluororesin. A commercially available product can be used as the adhesive. Although it does not specifically limit as a commercial item, LF series (acrylic adhesive) etc. of Pirarax (Pyralux, DuPont Co., Ltd.) etc. are mentioned. Among these, preferred forms are a copper clad laminate using an LCP film, and a copper clad laminate in which a base film and a copper foil are laminated via a fluororesin.

  The polyimide film used for the copper clad laminate may be the same as the polyimide film for the FPC coverlay, and the composition may be the same as or different from the polyimide film for the coverlay. Good.

  Although it does not specifically limit as a fluorine resin used for the said copper clad laminated body, A well-known fluorine resin can be used and a commercial item may be used. Examples of the commercially available products include Toyoflon F, FE, FL, FR, and FV (trade names; above, manufactured by Toray Film Processing Co., Ltd.).

  The thickness of the polyimide layer in the copper-clad laminate (when using a polyimide adhesive, the layer including the adhesive) is not particularly limited, but is 0.01 to 2.0 times the thickness of the fluororesin layer. The degree is preferable, about 0.05 to 1.0 times is more preferable, and about 0.1 to 0.9 times is more preferable. When the thickness of the polyimide layer exceeds 2.0 times the thickness of the fluororesin layer, although the rigidity and dimensional stability as a copper clad laminate are improved, the dielectric constant increases, which is not preferable. Moreover, when it is less than 0.01 times, the rigidity of the polyimide layer decreases and the linear expansion coefficient tends to increase, and the rigidity and dimensional stability as a copper clad laminate decrease.

  The copper clad laminate is etched to obtain a copper clad laminate obtained by wiring. The method for the etching treatment is not particularly limited, and a known method can be used.

  In the manufacture of the high-frequency circuit board, the FPC coverlay is laminated so that the fluororesin side is in contact with the circuit of the copper clad laminate, and the coverlay and the copper clad laminate are temporarily fixed.

  As a temporary fixing process of the copper clad laminate and the cover lay, a known method can be used, and is not particularly limited. For example, the copper clad laminate and the cover lay are aligned and kiss-laminated. Later, if necessary, a method of laminating at a temperature of about 150 to 200 ° C. by quick pressing, a method of aligning the copper clad laminate and the cover lay, and a method of multi-stage pressing can be mentioned. The maximum temperature in the temporary fixing step is not particularly limited as long as it is lower than the melting point of the fluororesin used for the coverlay, but is within the range of 100 to 250 ° C. from the viewpoint that sufficient adhesive strength can be obtained by the subsequent annealing treatment. Is preferable. The processing time of the temporary fixing process is not particularly limited.

  Although it does not specifically limit in manufacture of a high frequency circuit board, It is preferable to perform the process of annealing the copper clad laminated body to which the coverlay was attached following the said temporary fixing process.

  The maximum heating temperature in the annealing process is not particularly limited, but the temperature higher than the maximum temperature in the temporary fixing process within the range of 150 ° C. or higher and 350 ° C. or lower is the adhesive strength of the resulting high-frequency circuit board. The temperature difference is preferably 20 ° C. or more. Moreover, it is preferable that the annealing process is performed with free tension at 150 ° C. or more and 350 ° C. or less. Free tension has the advantage of simplifying the treatment process, and the annealing temperature is more preferably 200 ° C. or higher and 280 ° C. or lower, and further preferably 205 ° C. or higher and 275 ° C. or lower. The annealing time is not particularly limited.

  By the annealing treatment, the adhesive strength is increased based on the adhesive strength of the fluororesin layer, and a high-frequency circuit board having a practical adhesive strength (peel strength) is obtained. The adhesive strength after annealing treatment of the obtained high-frequency circuit board is preferably a value exceeding 8 N / cm, more preferably 10 N / cm or more from the viewpoint of securing the performance as a coverlay. More preferably, it is 14 N / cm or more. The adhesive strength in the present invention is a value measured by the method described in Examples described later.

<FFC>
The FFC can be manufactured by thermocompression bonding with a conductor sandwiched between the FFC substrates of the present invention.
FFC, for example, heats two FFC base materials of the present invention formed by bonding the polyimide film and the fluororesin in an adhesive state so that the fluororesin layer faces each other with a conductor in between. A method in which the two pieces of the fluororesin layer are bonded to each other while being heated so that the molded members face each other with the conductor interposed therebetween, and then the two polyimide films are It can manufacture using the method etc. which laminate | paste up and down the molded object of the fluororesin layer after bonding. The thermocompression bonding can be performed using a method similar to the method used in the above-described manufacturing method of the coverlay or FFC substrate.

  The conductor is not particularly limited, and examples thereof include a flat foil or round wire of conductive metal, a rectangular conductor having a rectangular cross section, and an organic conductor. Although it does not specifically limit as a conductive metal, Copper, silver, tin, indium, aluminum, molybdenum, these alloys, etc. can be used. The width and thickness of the conductor are not particularly limited, but are, for example, about 20 μm to 0.5 mm.

  A high frequency circuit board can be produced by laminating the coverlay of the present invention and a copper-clad laminate subjected to wiring processing, or by sandwiching a conductor with the FFC base material of the present invention. The high-frequency circuit board has not only the electrical characteristics and mechanical characteristics further increased, but also excellent dimensional stability because the thickness of the polyimide film and the thickness of the fluororesin is the specific ratio described above. Even if an etching process for forming a circuit or various heating processes in the post-process after the circuit is formed, the occurrence of curling, twisting, warping, etc. can be further suppressed.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples at all, and many variations are within the technical idea of the present invention. This is possible by those with ordinary knowledge.

  A method for measuring various characteristics in the present invention will be described below.

(1) Peel strength A sample is cut into a strip shape with a width of 10 mm, and a 90 ° C pull test (tensile speed: 50 mm / min, measurement length: 20 mm, measurement using Shimadzu Universal Tensile Tester Autograph AG-IS) The peel strength was measured in the range (5.0-20.0 mm) (unit: N / cm).

(2) Storage elastic modulus, loss elastic modulus, Tg
Samples were cut to a size of 5 mm × 50 mm, and storage elastic modulus and loss elastic modulus were measured using a viscoelastic device DMS EXSTER6000 manufactured by SII in a nitrogen atmosphere in the range of room temperature to 400 ° C. and a frequency of 10 Hz.
From the obtained loss elastic modulus data, the temperature at the time of peaking was defined as Tg.

(3) Measurement of adhesion force A sample was cut into a size of 10 mm x 150 mm, and was measured with a universal length tester (model number) manufactured by Shimadzu Corporation by 90 ° and a measurement length of 20 mm.
The value measured within 10 hours after the preparation of the sample was the initial adhesion, and the value measured after the sample was treated for 96 hours in an environment of 85 ° C. and 85 RH% was defined as the moisture adhesion resistance.

[Synthesis Example 1]
Pyromellitic dianhydride (molecular weight 218.12) / 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (molecular weight 294.22) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) Was prepared in a molar ratio of 45/55/100 and polymerized to a 20 wt% solution in DMAc (N, N-dimethylacetamide) to obtain a 3500 poise polyamic acid solution.

[Synthesis Example 2]
Pyromellitic dianhydride (molecular weight 218.12) / 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (molecular weight 294.22) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) / Paraphenylenediamine (molecular weight 108.14) is prepared in a molar ratio of 95/5/85/15, polymerized to a 20 wt% solution in DMAc (N, N-dimethylacetamide), and polymerized to 3500 poise An acid solution was obtained.

[Synthesis Example 3]
3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (molecular weight 294.22) / 1,3-bis (3-aminophenoxy) benzene (molecular weight 292.34) in a molar ratio of 100/100 Was prepared in a ratio of 20 wt% in DMAc (N, N-dimethylacetamide) and polymerized to obtain a 3300 poise polyamic acid solution.

[Synthesis Example 4]
After 380 L of distilled water was charged into the autoclave and sufficiently substituted with nitrogen, 75 kg of 1-fluoro-1,1-dichloroethane, 155 kg of hexafluoropropylene, perfluoro (1,1,5-trihydro-1-pentene) 0.5 kg was charged, and the inside of the system was maintained at 35 ° C. and a stirring speed of 200 rpm. Thereafter, tetrafluoroethylene was injected to 0.7 MPa, ethylene was subsequently injected to 1.0 MPa, and then 2.4 kg of di-n-propyl peroxydicarbonate was added to initiate polymerization. Since the system pressure decreases as the polymerization proceeds, a mixed gas of tetrafluoroethylene / ethylene / hexafluoropropylene = 40.5 / 44.5 / 15.0 mol% is continuously supplied, and the system pressure is reduced to 1 It was kept at 0.0 MPa. And perfluoro (1,1,5-trihydro-1-pentene) was continuously charged with a total amount of 1.5 kg, and stirring was continued for 20 hours. And after releasing pressure and returning to atmospheric pressure, the reaction product was washed with water and dried to obtain 200 kg of powder (fluorinated ethylenic polymer FA).

[Synthesis Example 5]
In the same manner as in Synthesis Example 4, a fluorine-containing ethylenic polymer FB was obtained with the formulation shown in Table 1.

[Synthesis Example 6]
9.5 kg of the fluorine-containing ethylenic polymer FB powder obtained in Synthesis Example 5, 700 g of 28% ammonia water and 10 L of distilled water were charged into an autoclave, and the system was heated while stirring and maintained at 80 ° C. Stirring was continued for an hour. The contents were washed with water and dried to obtain 9.2 kg of powder (fluorinated ethylenic polymer FC). By performing such treatment, the active functional groups (carbonate groups and carboxylic acid fluoride groups) contained in the resin were converted into chemically and thermally stable amide groups. In addition, it was confirmed by infrared spectrum analysis that this conversion progressed quantitatively.
The analysis results of Synthesis Examples 4 to 6 are shown in Table 1.

[Example 1]
(1) Preparation of polyimide film Acetic anhydride (molecular weight 102.09) and β-picoline were mixed and stirred in the polyamic acid solution obtained in Synthesis Example 1 at a ratio of 17% by weight and 17% by weight, respectively. did. The obtained mixture was cast on a 75 ° C. stainless steel drum rotated by a T-shaped slit die, cast for 30 seconds, and then heated in the running direction while heating the obtained gel film at 100 ° C. for 5 minutes. The film was stretched 1.2 times. Next, both ends in the width direction were held and stretched 1.3 times in the width direction while heating at 270 ° C. for 2 minutes, and then heated at 380 ° C. for 5 minutes to obtain a polyimide film having a thickness of 12.5 μm.
The storage elastic modulus and loss elastic modulus of the obtained polyimide film were measured. The results are shown in Table 2. In Table 2, the storage modulus of the storage elastic modulus indicates the ratio of the storage elastic modulus at 300 ° C. with respect to the storage elastic modulus at 30 ° C., and the storage modulus of the loss elastic modulus is 300% with respect to the loss elastic modulus at 30 ° C. The ratio of loss elastic modulus at ° C is shown.
(2) Production of fluororesin film The fluorine-containing ethylenic polymer FA polymerized in Synthesis Example 4 was pelletized using a 65φ short-axis extruder with a set temperature of 230 ° C to 280 ° C, and then set temperature Was formed into a film with a 50φ short-shaft extruder equipped with a T die at 230 ° C. to 280 ° C. to obtain a 25 μm-thick fluororesin film.

(3) Production of coverlay A coverlay was produced by a vacuum press method using the polyimide film obtained in (1) above and the fluororesin film obtained in (2) above. Specifically, a polyimide film and a fluororesin film were superposed and pressed with a vacuum press machine at 200 ° C. and 3 MPa for 15 minutes to obtain a coverlay film.

(4) Preparation of FPC sample One side of a double-sided copper-clad plate was etched to form lines / spaces of 0.5 mm / 0.5 mm, and the coverlay obtained in (3) above was 180 using a vacuum press. Pressing was performed at 3 ° C. for 15 minutes, followed by annealing at 230 ° C. for 15 minutes.

(5) Evaluation of initial adhesion and moisture-resistant adhesion The initial adhesion and moisture-resistant adhesion between the polyimide film layer and the fluororesin layer were measured using the FPC sample obtained in (4) above. Moreover, the adhesive force retention rate calculated the ratio of the initial adhesive force with respect to moisture-proof adhesive force. These results are shown in Table 3.

[Example 2]
The following samples were prepared using the polyimide film obtained in Example 1 (1) and the fluororesin film obtained in Example 1 (2), and the adhesion was evaluated.
(1) Preparation of FFC sample FFC arranges 51 copper wires of width 0.50mm and thickness 0.022mm in the pitch between conductors of 0.50mm on the fluororesin layer side of the FFC substrate of the present invention. Further, a flame retardant flexible flat cable was manufactured by applying a structure in which the fluororesin layer side of the FFC substrate of the present invention was further stacked thereon, and pressurizing with a hot roll at 200 ° C. and 0.5 MPa.
(2) Evaluation of initial adhesion and moisture-resistant adhesion Using the obtained FFC sample, initial adhesion and moisture-resistant adhesion were measured. The results are shown in Table 3.

[Example 3]
Example 1 (3), except that a Kapton KJ type (thickness: 25 μm) manufactured by DuPont USA was used for the polyimide film layer and the fluororesin film obtained in Example 1 (2) was used for the fluororesin layer. In the same manner as in (4) and (5), FPC sample preparation, initial adhesion and moisture resistance adhesion were evaluated. The results are shown in Table 3.

[Example 4]
Example 1 (3) except that the fluorine-containing ethylenic polymer (F-B) obtained in Synthesis Example 5 was used in place of the fluorine-containing ethylenic polymer (F-A) obtained in Synthesis Example 4. In the same manner as in (4) and (5), FPC sample preparation, initial adhesion and moisture resistance adhesion were evaluated. The results are shown in Table 3.

[Example 5]
Using the polyamic acid obtained in Synthesis Example 2 on the polyimide film obtained by processing in the same manner as in Example 1 (1), the polyamic acid solution obtained in Synthesis Example 3 is 5 μm thick. It was applied and the temperature was raised stepwise from 200 degrees to 400 degrees using a heating furnace to obtain a multilayer polyimide film layer.
FPC sample creation, initial adhesion strength, and moisture-resistant adhesion strength were evaluated in the same manner as in Example 1 (3), (4), and (5) except that the multilayer polyimide film was used as the polyimide film layer. The joint surface of the multilayer polyimide film layer and the fluororesin film layer at this time is a film layer using the polyamic acid obtained in Synthesis Example 3 and a fluorine-containing ethylenic polymer (FA).
Separately, the storage elastic modulus and loss elastic modulus of only the polyimide film produced using the polyamic acid obtained from Synthesis Example 2 were measured. The results are shown in Table 2.
Furthermore, using the polyamic acid obtained in Synthesis Example 3, a polyimide film was produced in the same manner as in (1) of Example 1, and the storage elastic modulus and loss elastic modulus of the obtained polyimide film were measured. The results are shown in Table 2.

  At least in part, the polyimide film used in the present invention has a glass transition point of 300 ° C. or less, a storage modulus storage rate of 50% or less, and a loss modulus storage rate of 200% or more. It could be confirmed.

[Comparative Example 1]
Using the polyamic acid obtained in Synthesis Example 2, the polyimide film obtained in the same manner as in Example 1 (1) and the fluorine-containing ethylenic polymer (FA) obtained in Synthesis Example 4 were used. Except for the above, FPC sample preparation, initial adhesion and moisture resistance adhesion were evaluated in the same manner as in Examples 1 (3), (4) and (5). The results are shown in Table 3.

[Comparative Example 2]
An FPC sample was prepared in the same manner as in Examples 1 (3), (4) and (5) except that the fluorine-containing ethylenic polymer (F-C) obtained in Synthesis Example 6 was used as the fluororesin layer. Evaluation of initial adhesion and moisture-resistant adhesion was carried out. The results are shown in Table 3.

  From the above results, the FPC manufactured using the coverlay of the present invention and the FFC manufactured using the FFC substrate of the present invention are under an environment of 85 ° C. and 85 RH% between the polyimide film layer and the fluororesin layer. It was confirmed that the adhesion strength (moisture resistance adhesion strength) after 96 hours was maintained at 50% or more with respect to the initial adhesion strength between the polyimide film layer and the fluororesin layer.

  As described above, when the coverlay or FFC base material of the present invention is used, it is excellent in workability at the time of manufacturing a high-frequency circuit board, and 96 hours have elapsed under an environment of 85 ° C. and 85 RH% between the polyimide film layer and the fluororesin layer A high-frequency circuit board excellent in later adhesion (moisture-resistant adhesion) was obtained.

  The FPC coverlay and FFC substrate of the present invention are excellent in adhesion (moisture-resistant adhesion) after 96 hours in an environment of 85 ° C. and 85 RH% between the polyimide film layer and the fluororesin layer. Since the adhesiveness between the fluororesin layers is excellent, a high-frequency circuit board flexible printed wiring board and a flexible flat cable excellent in processability can be obtained. Moreover, since the high frequency circuit board manufactured using the FPC coverlay and the FFC base material of the present invention has a low dielectric constant, transmission loss can be suppressed.

Claims (10)

  A base material for a coverlay or a flexible flat cable (FFC) comprising a polyimide film layer and a fluororesin layer, and an adhesive force after 96 hours in an environment of 85 ° C. and 85 RH% between the polyimide film layer and the fluororesin layer. (Moisture resistant adhesion) is maintained at 50% or more of the initial adhesion between the polyimide film layer and the fluororesin layer, a coverlay or FFC substrate.   The base material for coverlay or FFC according to claim 1, wherein the glass transition point of at least an arbitrary part of the polyimide film layer is 300 ° C or lower.   The cover according to claim 1 or 2, wherein the storage elastic modulus at 300 ° C is 50% or less when the storage elastic modulus at 30 ° C in at least an arbitrary part of the polyimide film layer is 100%. Ray or FFC substrate.   When the loss elastic modulus at 30 ° C. in at least an arbitrary part of the polyimide film layer is 100%, the loss elastic modulus in the region of 30 to 300 ° C. has an apex that is a value of 200% or more. The base material for coverlays or FFC of any one of Claims 1-3.   The coverlay or FFC substrate according to any one of claims 1 to 4, wherein the melting point of the fluororesin is 200 ° C or lower.   The coverlay or FFC group according to any one of claims 1 to 5, wherein the fluororesin is a fluorine-containing ethylenic polymer, and the fluorine-containing ethylenic polymer contains a carbonyl group. Wood. 7. The coverlay or FFC according to claim 6, wherein the carbonyl group content of the fluorine-containing ethylenic polymer is 3 to 1000 in total with respect to 1 × 10 ⁶ main chain carbon atoms. Base material. The fluorine-containing ethylenic heavy polymer having at least one selected from the group consisting of a carbonate group, a carboxylic acid halide group and a carboxylic acid group with a total of 3 to 1000 carbon atoms per 1 × 10 ⁶ main chain carbon atoms. The coverlay or FFC substrate according to any one of claims 1 to 5, wherein the coverlay or the FFC substrate is formed of a coalescence. The fluororesin is tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, vinyl fluoride, hexafluoropropylene, hexafluoroisobutene, the following formula (X):
_{^{CH 2 = CR 1 (CF 2}} ) n R 2 (X)
(In the formula, R1 represents H or F, R2 represents H, F or Cl, and n represents a positive integer of 1 to 10.)
1 or more types of fluorine-containing ethylenic monomers selected from the group consisting of monomers represented by formula (2) and perfluoro (alkyl vinyl ethers) having 2 to 10 carbon atoms, or the fluorine-containing ethylenic monomers and carbon The coverlay or FFC substrate according to any one of claims 1 to 5, which is a fluorine-containing ethylenic polymer obtained by polymerizing an ethylenic monomer having a number of 5 or less. The coverlay or FFC substrate according to any one of claims 1 to 5, wherein the fluororesin is a copolymer obtained by polymerizing at least the following (a), (b) and (c).
(A) Tetrafluoroethylene 20-90 mol%
(B) 10-80 mol% ethylene
(C) Formula CF ₂ = CFR ³ (Y)
(In the formula, R ³ represents CF ₃ or OR ⁴ , and R ⁴ represents a perfluoroalkyl group having 1 to 5 carbon atoms.)
1 to 70 mol% of a compound represented by