JP2005248134A - Flame retardant adhesive composition, and cover lay film and flexible copper clad laminate plate by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition of which cured material obtained by curing is excellent in flame retardant property and electric characteristics (migration resistance) and without containing a halogen, and a cover lay film and flexible copper clad laminate plate by using the same. <P>SOLUTION: This flame retardant adhesive composition contains (A) a non-halogen-based epoxy resin, (B) a thermoplastic resin and/or synthetic rubber, (C) a curing agent, (D) a curing accelerator, (E) a phosphorus-containing plasticizer and (F) an inorganic filler. The cover lay film and flexible copper clad laminate plate by using the same are also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an adhesive composition in which a cured product obtained by curing is excellent in flame retardancy and does not contain a halogen, and a coverlay film and a flexible copper-clad laminate using the composition.

  Adhesives used for electronic materials such as semiconductor encapsulating materials, build-up substrates, and glass-epoxy copper-clad laminates have traditionally had excellent flame resistance by compounding bromine-containing epoxy resins, phenoxy resins, etc. Is shown. In the case where a compound containing halogen such as bromine is burned, there is a concern that harmful gases such as dioxin compounds may be generated. Therefore, in recent years, non-halogenation of materials used for adhesives has been studied.

  On the other hand, flexible copper-clad laminates are widely used as materials that are thinner and more flexible than the build-up substrates and glass-epoxy copper-clad laminates. The market scale is expanding with the shift to the market. The flexible copper-clad laminate is a copper-clad laminate having flexibility obtained by bonding a polyimide film and a copper foil by heating through an adhesive and thermosetting the adhesive. As for the adhesive used for the flexible copper-clad laminate, as in the adhesive used for the electronic material described above, non-halogenation of the material has been studied.

  In addition, after processing the copper foil of the flexible copper-clad laminate to form a wiring pattern, electrical insulation such as a polyimide film with an adhesive as a material covering the wiring pattern forming surface to protect the wiring A film (coverlay film) is used. These flexible copper-clad laminates and coverlay film materials include, for example, adhesion between electrical insulating films and copper foil, heat resistance, solvent resistance, electrical properties (migration resistance), and dimensional stability. Further, characteristics such as storage stability and flame retardancy are required.

  In order to satisfy the above requirements, for example, an adhesive composition containing an epoxy resin, a carboxyl group-containing acrylonitrile butadiene rubber, a curing agent, a curing accelerator and a solid plasticizer (such as a phosphate ester compound), and the same are used. A flexible copper-clad laminate is disclosed (Patent Document 1). In addition, an adhesive composition containing an epoxy resin, a carboxyl group-containing acrylonitrile butadiene rubber, a curing agent, a curing accelerator and an aromatic phosphate, and a flexible printed circuit board using the same are disclosed (Patent Documents). 2). However, a cured product obtained by curing any of the adhesive compositions was not excellent in flame retardancy and electrical characteristics (migration resistance).

JP 2002-047470 A JP 2003-055639 A

  An object of the present invention is to provide a halogen-free adhesive composition in which a cured product obtained by curing exhibits excellent flame retardancy and electrical characteristics (migration resistance), and a coverlay film using the composition And providing a flexible copper clad laminate.

In order to solve the above problems, the present invention
(A) non-halogen epoxy resin,
(B) thermoplastic resin and / or synthetic rubber,
(C) a curing agent,
(D) a curing accelerator,
Provided is a flame retardant adhesive composition comprising (E) a phosphorus-containing plasticizer and (F) an inorganic filler.

  Secondly, the present invention provides a coverlay film having an electrically insulating film that has been subjected to a low-temperature plasma treatment, and a layer comprising the composition provided on the film.

  Thirdly, the present invention provides a flexible copper-clad laminate having an electrically insulating film that has been subjected to low-temperature plasma treatment, a layer comprising the composition provided on the film, and a copper foil.

  The cured product obtained by curing the composition of the present invention is excellent in flame retardancy, peel strength, electrical properties (migration resistance) and solder heat resistance, and does not contain halogen. Therefore, the coverlay film and flexible copper clad laminate produced using this composition are also excellent in flame retardancy, peel strength, electrical properties (migration resistance) and solder heat resistance.

<Flame-retardant adhesive composition>
Hereinafter, the constituent components of the flame retardant adhesive composition of the present invention will be described in more detail. In this specification, room temperature means 25 ° C. The glass transition point (Tg) means a glass transition point measured by the DMA method.

[(A) Non-halogen epoxy resin]
The non-halogen epoxy resin as component (A) is an epoxy resin that does not contain a halogen atom such as bromine in its molecule, and has at least two epoxy groups in one molecule. This epoxy resin is not specifically limited, For example, you may contain silicone, urethane, a polyimide, polyamide, etc. Further, the skeleton may contain a phosphorus atom, a sulfur atom, a nitrogen atom, or the like.

  Examples of such an epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, or those hydrogenated thereto; glycidyl ether type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; Glycidyl ester epoxy resins such as hexahydrophthalic acid glycidyl ester and dimer acid glycidyl ester; Triglycidyl isocyanurate, tetraglycidyl diaminodiphenylmethane and other glycidyl amine epoxy resins; Linear aliphatic such as epoxidized polybutadiene and epoxidized soybean oil Epoxy resin, etc., preferably bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novo Click type epoxy resins. As these commercially available products, for example, Epicoat 828 (manufactured by Japan Epoxy Resin, two epoxy groups in one molecule), Epicron 830S (manufactured by Dainippon Ink & Chemicals, epoxy group in one molecule: 2 under the trade name) ), Epicoat 517 (manufactured by Japan Epoxy Resin, epoxy groups in one molecule: two), EOCN103S (manufactured by Nippon Kayaku, epoxy groups in one molecule: two or more), and the like.

In addition, various phosphorus-containing epoxy resins in which phosphorus atoms are bonded using a reactive phosphorus compound are also effectively used when constituting a flame-retardant adhesive composition that does not contain halogen. Specifically, for example, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (manufactured by Sanko Co., Ltd., trade name: HCA) is bonded to the phosphorus atom of this compound. A compound obtained by reacting a compound obtained by substituting the active hydrogen atom with hydroquinone (trade name: HCA-HQ, manufactured by Sanko Co., Ltd.) with the above-described epoxy resin is used. As these commercial products, for example, under the trade name, FX305 (manufactured by Tohto Kasei Co., Ltd., phosphorus content: 3%, epoxy group in one molecule: 2 or more), Epicron EXA9710 (Dainippon Ink Chemical Co., Ltd. ( Co., Ltd., phosphorus content: 3%, epoxy groups in one molecule: 2 or more) and the like.
The said epoxy resin may be used individually by 1 type, or may use 2 or more types together.

[(B) Thermoplastic resin / synthetic rubber]
-Thermoplastic resin The thermoplastic resin which can be used as (B) component is a high molecular compound whose glass transition point (Tg) is room temperature or more. The weight average molecular weight is usually from 1,000 to 5,000,000, preferably from 5,000 to 1,000,000. The thermoplastic resin is not particularly limited, and examples thereof include polyester resins, acrylic resins, phenoxy resins, polyamideimide resins, and epoxy resins having a weight average molecular weight of 1,000 or more. Among these resins, these resins contain a carboxyl group. It is preferable. When it contains a carboxyl group, when the composition obtained is applied to a coverlay film, it is effective in that the adhesive exhibits an appropriate flowability when laminated and integrated by hot pressing. (Flow characteristics). This flow of adhesive covers and protects the copper foil portion (wiring pattern) forming a circuit on the flexible copper-clad laminate without any gaps. It is also effective in improving the adhesion between the copper foil and an electrically insulating film such as a polyimide film.

  The ratio of the carboxyl group in the carboxyl group-containing thermoplastic resin is not particularly limited, but the content of the monomer unit having the carboxyl group is preferably 1 to 10 mol%, particularly preferably 2 to 6 mol%. It is. When this ratio satisfies the range of 1 to 10 mol%, the flow characteristics and solder heat resistance when applied to the coverlay film are further improved, and the stability of the adhesive varnish is further improved.

  As a commercial item of a carboxyl group-containing thermoplastic resin, for example, under the trade name, “Byron” series (manufactured by Toyobo, carboxyl group-containing polyester resin), 03-72-23 (manufactured by Kyodo Pharmaceutical, carboxyl group-containing acrylic resin), “KS” series (manufactured by Hitachi Chemical Co., Ltd., epoxy group-containing acrylic resin) and the like.

  Other commercially available thermoplastic resins include, for example, “YP” series, “ERF” series (manufactured by Tohto Kasei, phenoxy resin), Epicoat 1256 (manufactured by Japan Epoxy Resin, phenoxy resin), “Vilomax”. "Series (manufactured by Toyobo, polyamide-imide resin)," Kayaflex "series (manufactured by Nippon Kayaku, polyamide-imide resin), and the like.

  Next, the characteristics of each thermoplastic resin exemplified above will be described. When a composition containing an acrylic resin is used for the coverlay film, a film having particularly excellent migration resistance can be obtained. When a composition containing a phenoxy resin or a polyamideimide resin is used for the coverlay film, the flexibility is further improved. Use of a composition containing an epoxy resin having a weight average molecular weight of 1,000 or more is particularly useful in terms of imparting appropriate adhesiveness and flexibility to the obtained coverlay film and flexible copper-clad laminate.

Synthetic rubber Synthetic rubber that can be used as another component (B) is a polymer compound having a glass transition point (Tg) of less than room temperature. Although it does not restrict | limit especially as this synthetic rubber, When it mix | blends with the composition used for a flexible copper clad laminated board and a coverlay film, the adhesiveness of electrical insulation films, such as copper foil and a polyimide film, will improve more. Among these, carboxyl group-containing acrylonitrile-butadiene rubber (hereinafter, “acrylonitrile-butadiene rubber” is also referred to as “NBR”) is preferable.

  As the carboxyl group-containing NBR, for example, acrylonitrile and butadiene are mixed so that the amount of acrylonitrile with respect to the total amount of acrylonitrile and butadiene is preferably 5 to 70% by mass, particularly preferably 10 to 50% by mass. Examples thereof include a polymerized copolymer rubber obtained by carboxylating the molecular chain terminal, or a copolymer rubber of acrylonitrile and butadiene with a carboxyl group-containing monomer such as acrylic acid or maleic acid. For this carboxylation, for example, a monomer having a carboxyl group such as methacrylic acid can be used.

  The ratio of the carboxyl group in the carboxyl group-containing NBR (that is, the ratio of the monomer unit having the carboxyl group to the total monomers constituting the carboxyl group-containing NBR) is not particularly limited, but preferably 1 -10 mol%, particularly preferably 2-6 mol%. When this ratio satisfies the range of 1 to 10 mol%, the fluidity of the resulting composition can be controlled, so that good curability can be obtained.

  As such a carboxyl group-containing NBR, for example, NIPPOL 1072 (manufactured by ZEON Corporation), PNR-1H (manufactured by JSR), which is a high purity product with a small amount of ionic impurities, and the like can be used. High-purity carboxyl group-containing acrylonitrile butadiene rubber cannot be used in a large amount due to its high cost, but it is effective in that it can improve adhesion and migration resistance at the same time.

  Furthermore, when applying the adhesive composition of the present invention to a coverlay film, it is effective to use hydrogenated NBR together. In these synthetic rubbers, since the double bond of butadiene in the NBR rubber is made into a single bond by hydrogenation, the butadiene rubber component does not deteriorate with respect to the thermal history. Therefore, there is little decrease in the peel strength between the adhesive composition and the copper foil due to the heat history and the decrease in migration resistance due to heating. By using the carboxyl group-containing NBR and hydrogenated NBR in combination, a coverlay film and a flexible copper-clad laminate having further balanced characteristics can be obtained. Specifically, for example, Zetpol series (manufactured by Nippon Zeon Co., Ltd.) can be given as a trade name.

  The thermoplastic resin and the synthetic rubber may be used singly or in combination of two or more. As the component (B), one of the thermoplastic resin and the synthetic rubber may be used alone, or both of them may be used in combination.

  The amount of component (B) (total amount when thermoplastic resin and synthetic rubber are used in combination) is not particularly limited, but is usually 10 to 300 parts by weight, preferably 100 parts by weight of component (A), preferably 20 to 200 parts by mass. When the component (B) satisfies the range of 10 to 300 parts by mass, the obtained flexible copper-clad laminate and the coverlay film are excellent in flame retardancy and peel strength from the copper foil.

[(C) curing agent]
The curing agent which is component (C) is not particularly limited as long as it is normally used as a curing agent for epoxy resins. Examples of the curing agent include a polyamine curing agent (also referred to as “polyamine compound”), an acid anhydride curing agent (also referred to as “acid anhydride”), a boron trifluoride amine complex salt, a phenol resin, and the like. . Examples of polyamine curing agents include aliphatic amine curing agents such as diethylenetriamine, tetraethylenetetramine, and tetraethylenepentamine; alicyclic amine curing agents such as isophoronediamine; aromatic amines such as diaminodiphenylmethane and phenylenediamine. System curing agents; dicyandiamide and the like. Examples of the acid anhydride curing agent include phthalic anhydride, pyromellitic acid anhydride, trimellitic acid anhydride, hexahydrophthalic anhydride, and the like. Among them, a polyamine-based curing agent is preferable because appropriate reactivity is required when the obtained composition is used for a coverlay film, and when it is used for a flexible copper-clad laminate, more excellent heat resistance can be imparted. To acid anhydride curing agents are preferred.
The said hardening | curing agent may be used individually by 1 type, or may use 2 or more types together.

  Although the compounding quantity of (C) component is not specifically limited, It is 0.5-100 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is 1-20 mass parts.

[(D) Curing accelerator]
(D) The hardening accelerator which is a component will not be specifically limited if it is used for acceleration | stimulation of reaction with (A) non-halogen-type epoxy resin and (C) hardening | curing agent. Examples of the curing accelerator include 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, and ethyl isocyanate compounds of these compounds, 2-phenylimidazole, 2-phenyl-4-methylimidazole. Imidazole compounds such as 2-phenyl-4-methyl-5-hydroxymethylimidazole and 2-phenyl-4,5-dihydroxymethylimidazole; triphenylphosphine, tributylphosphine, tris (p-methylphenyl) phosphine, tris (p -Triorganophosphines such as methoxyphenyl) phosphine, tris (p-ethoxyphenyl) phosphine, triphenylphosphine / triphenylborate, tetraphenylphosphine / tetraphenylborate; Phonium salts; Tertiary amines such as triethyleneammonium triphenylborate, and tetraphenylborates thereof, borofluorides such as zinc borofluoride, tin borofluoride, nickel borofluoride; tin octylate, zinc octylate, etc. An octylate etc. are mentioned.
The said hardening accelerator may be used individually by 1 type, or may use 2 or more types together.

  Although the compounding quantity of (D) component is not specifically limited, It is 0.1-15 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is 1-10 mass parts, Most preferably, it is 1-8 mass. Part.

[(E) phosphorus-containing plasticizer]
The phosphorus-containing plasticizer as the component (E) is not particularly limited, but is preferably a phosphate ester compound or a phosphazene compound.

Since the phosphazene compound contains a phosphorus atom and a nitrogen atom in the molecule, it acts as a component imparting flame retardancy in the obtained coverlay film and flexible copper-clad laminate. Although the said phosphazene compound is not specifically limited, The compound which does not contain a halogen and has a phosphazene structure in a molecule | numerator is preferable. Here, the phosphazene structure means a structure represented by the formula: —P (R ₂ ) ═N— [wherein R is an organic group]. As such a phosphazene compound, for example, a cyclophosphazene oligomer is preferable from the viewpoint of heat resistance, moisture resistance, flame retardancy, and chemical resistance.

  This cyclophosphazene oligomer has the following general formula:

[Wherein X is the same or different and is an organic group containing no hydrogen atom or halogen atom, and n is an integer of 3 to 10]
The melting point thereof is preferably 80 ° C. or higher, more preferably 90 to 150 ° C., and particularly preferably 100 to 150 ° C. In the above general formula, n is preferably an integer of 3 to 9, more preferably 3 to 6. In the above general formula, examples of the organic group containing no halogen atom represented by X include an alkoxy group, a phenoxy group, an amino group, and an allyl group.

  These compounds are used as non-halogen flame retardants, but they are all plastic, and when used in coverlay films or flexible copper-clad laminates, they are not only flame retardant but also adhere to copper foil. It also contributes to improving the performance. As these commercially available products, for example, PX-200 (manufactured by Daihachi Chemical, phosphate ester compound), FX-500 (manufactured by Asahi Denka, phosphate ester compound), SPE-100 (manufactured by Otsuka Chemical, Phosphazene compounds).

  The phosphate ester compound and the phosphazene compound may be used singly or in combination of two or more. In addition, as the component (E), either a phosphate ester compound or a phosphazene compound may be used alone, or both of them may be used in combination.

  Although the compounding quantity of (E) component is not specifically limited, From a viewpoint of ensuring favorable flame retardance, Preferably it is 5 with respect to a total of 100 mass parts of the organic resin component and inorganic solid component in adhesive composition. It is -50 mass parts, More preferably, it is 7-30 mass parts.

[(F) inorganic filler]
The inorganic filler as the component (F) is not particularly limited as long as it is conventionally used for a coverlay film or a flexible copper clad laminate. Specific examples thereof include metal oxides such as aluminum hydroxide, magnesium hydroxide, silicon dioxide, and molybdenum oxide from the point of acting also as a flame retardant aid, preferably aluminum hydroxide, magnesium hydroxide. Is mentioned. These inorganic fillers may be used alone or in combination of two or more.

  (F) Although the compounding quantity of a component is not specifically limited, Preferably it is 5-60 mass parts with respect to a total of 100 mass parts of the organic resin component in an adhesive composition, and an inorganic solid component, More preferably, 7 -30 mass parts.

[Other optional ingredients]
In addition to the above components (A) to (F), other optional components may be added.

Organic solvent The above components (A) to (F) and components added as necessary may be used in the production of flexible copper-clad laminates and coverlay films without solvent, but are dissolved in organic solvents or The composition may be dispersed and the composition may be prepared and used as a solution or dispersion (hereinafter simply referred to as “solution”). Examples of the organic solvent include N, N-dimethylacetamide, methyl ethyl ketone, N, N-dimethylformamide, cyclohexanone, N-methyl-2-pyrrolidone, toluene, methanol, ethanol, isopropanol, acetone, and the like. N-dimethylacetamide, methyl ethyl ketone, N, N-dimethylformamide, cyclohexanone, N-methyl-2-pyrrolidone, particularly preferably N, N-dimethylacetamide and methyl ethyl ketone are exemplified. These organic solvents may be used alone or in combination of two or more.

  The total concentration of the organic resin component and the inorganic solid component in the adhesive solution is usually 10 to 45% by mass, preferably 20 to 40% by mass. When this concentration satisfies the range of 10 to 45% by mass, the adhesive solution is excellent in workability because it has good applicability to a substrate such as an electrically insulating film, and there is no unevenness during coating. It is excellent in coating property and excellent in environmental aspect and economical efficiency.

  The “organic resin component” is a non-volatile organic component that constitutes a cured product obtained by curing the adhesive composition of the present invention. Specifically, the components (A) to (E) are mainly used. If the adhesive composition contains an organic solvent, the organic solvent is usually not included in the organic resin component. The “inorganic solid component” is a non-volatile inorganic solid component contained in the adhesive composition of the present invention. Specifically, it is a component (F), and includes a component added in some cases.

  What is necessary is just to mix the organic resin component in this composition, and the inorganic solid component and organic solvent added depending on the case using a pot mill, a ball mill, a homogenizer, a super mill, etc.

<Coverlay film>
The said composition can be used for manufacture of a coverlay film. Specifically, for example, a coverlay film having an electrically insulating film that has been subjected to low-temperature plasma treatment and a layer made of the above-described composition provided on the film can be mentioned. The manufacturing method will be described below.

  An adhesive solution prepared by mixing a required component and an organic solvent in advance to form a liquid is applied to an electrically insulating film subjected to low-temperature plasma treatment using a reverse roll coater, a comma coater, or the like. The electrically insulating film coated with the adhesive solution is passed through an in-line dryer, dried by removing the organic solvent at 80 to 160 ° C for 2 to 10 minutes, made into a semi-cured state, and then protected with a roll laminator A cover lay film is obtained by pressure bonding and laminating with a layer. The protective layer is peeled off during use. The “semi-cured state” means a state in which the composition is dried or a state in which the curing reaction proceeds in a part thereof.

  The thickness after drying of the composition coating film of the coverlay film is usually 5 to 45 μm, preferably 5 to 35 μm.

-Electrical insulation film The said electrical insulation film is used for the flexible copper clad laminated board of this invention, and a coverlay film. The electrical insulating film is not particularly limited as long as it is obtained by subjecting a material used for a flexible copper-clad laminate or coverlay film to a low temperature plasma treatment. Specifically, for example, polyimide film, polyethylene terephthalate film, polyester film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, aramid film; glass fiber, aramid fiber, polyester fiber, etc. Heat-resistant of the coverlay film obtained by impregnating a matrix epoxy resin, polyester resin, diallyl phthalate resin, etc., and then applying a low-temperature plasma treatment to a film or sheet laminated with copper foil From the viewpoints of dimensional stability, mechanical properties, etc., particularly preferred is a polyimide film subjected to low-temperature plasma treatment. As a polyimide film, what is normally used for a coverlay film should just be used. The thickness of the electrically insulating film may be any thickness as required, but is preferably 12.5 to 50 μm.

  In a preferred embodiment of the invention, a low temperature plasma treated polyimide film is used. The processing method of this film is as follows. Specifically, for example, a polyimide film is placed in a low-temperature plasma treatment apparatus that can be depressurized, the inside of the apparatus is in an atmosphere of an inorganic gas, and the pressure is maintained at 0.133 to 1,333 Pa, preferably 1.33 to 133 Pa, between the electrodes. A low voltage plasma of inorganic gas is generated by applying a direct current voltage or an alternating voltage of 0.1 to 10 kV to the glow discharge, and the film surface is continuously processed while moving the film. This processing time is usually 0.1 to 100 seconds. As said inorganic gas, inert gas, such as helium, neon, and argon, oxygen, carbon monoxide, a carbon dioxide, ammonia, air etc. can be used, for example. These inorganic gases may be used alone or in combination of two or more.

  The adhesion between the polyimide film and the adhesive layer formed on the film is improved by the low temperature plasma treatment. When a thermoplastic resin is used as the component (B) in the composition of the present invention, since the glass transition point (Tg) of these compounds is generally high, the adhesion between the polyimide film and the composition of the present invention. May be insufficient. In that case, the adhesiveness can be improved by combining low-temperature plasma-treated films. Further, when synthetic rubber is used as the component (B), it is advantageous in that the adhesiveness is further improved.

-Protective layer Although the said protective layer will not be specifically limited if it can peel, without impairing the form of an adhesive bond layer, Usually, a polyethylene (PE) film, a polypropylene (PP) film, a polymethylpentene (TPX) film, Examples include a plastic film such as a polyester film; a polyolefin film such as a PE film and a PP film, a release paper obtained by coating a TPX film or the like on one or both sides of a paper material.

<Flexible copper-clad laminate>
The said composition can be used for manufacture of a flexible copper clad laminated board. Specifically, for example, a flexible copper-clad laminate having an electrically insulating film, a layer made of the composition provided on the film, and a copper foil can be mentioned. As the electrical insulating film, those described as the electrical insulating film of the coverlay film can be used. The manufacturing method will be described below.

An adhesive solution prepared by mixing a required component and an organic solvent in advance to form a liquid is applied to an electrically insulating film subjected to low-temperature plasma treatment using a reverse roll coater, a comma coater, or the like. The electrically insulating film coated with the adhesive solution is passed through an in-line dryer, dried by removing the organic solvent at 80 to 160 ° C. for 2 to 10 minutes, and then semi-cured, and then copper foil and 100 to 150 A flexible copper-clad laminate can be obtained by heat laminating at 0 ° C. The flexible copper clad laminate is further aftercured to completely cure the semi-cured composition, thereby obtaining the final flexible copper clad laminate.
The thickness after drying of the composition coating film of the flexible copper-clad laminate is usually 5 to 45 μm, preferably 5 to 18 μm.

  As said copper foil, the rolling and electrolytic copper foil products conventionally used for the flexible copper clad laminated board can be used as it is. The thickness of this copper foil is usually 5 to 70 μm.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, these Examples do not limit this invention at all. The components (A) to (F) and other optional components used in the examples are specifically as follows. In addition, the unit of the numerical value which shows the compounding ratio in a table | surface is a "mass part."

<Adhesive composition components>
・ (A) Non-halogen epoxy resin (1) Epicron HP7200 (trade name) (Dainippon Ink Chemical Co., Ltd., epoxy groups in one molecule: 2)
(2) Epicoat 517 (trade name) (manufactured by Japan Epoxy Resin, 2 epoxy groups in one molecule)
(3) Epicoat 828 (trade name) (manufactured by Japan Epoxy Resin, 2 epoxy groups in one molecule)
(4) EOCN103S (trade name) (Nippon Kayaku, epoxy groups in one molecule: 2 or more)
(5) EPPN502H (trade name) (manufactured by Nippon Kayaku, epoxy groups in one molecule: 2 or more)
(6) EP4022 (trade name) (Asahi Denka, epoxy group in one molecule: 2 or more)
(7) EP-49-20 (trade name) (manufactured by Asahi Denka, epoxy group in one molecule: 2 or more)
(8) EPU-78-11 (trade name) (manufactured by Asahi Denka, two or more epoxy groups in one molecule)
(9) Epicron 9710 (trade name) (Dainippon Ink Chemical Co., Ltd., epoxy groups in one molecule: 2 or more)
(10) Epicron 830S (trade name) (Dainippon Ink Chemical Co., Ltd., epoxy groups in one molecule: 2)
(11) Epicron 4050 (trade name) (Dainippon Ink Chemical Co., Ltd., epoxy groups in one molecule: 2 or more)
(B-1) Thermoplastic resin (1) Byron 237 (trade name) (Toyobo, phosphorus-containing polyester resin)
(2) 03-72-23 (trade name) (manufactured by Kyodo Pharmaceutical, carboxyl group-containing acrylic resin)
(3) ERF-001-4 (trade name) (manufactured by Toto Kasei, phosphorus-containing phenoxy resin)
(4) Viromax HR15ET (trade name) (manufactured by Toyobo, polyamideimide resin)
(5) Epicoat 1256 (trade name) (made by Japan Epoxy Resin, Phenoxy Resin)
(6) KS8006 (trade name) (manufactured by Hitachi Chemical, epoxy group-containing acrylic resin)
・ (B-2) Synthetic rubber (1) Byron 30P (trade name) (manufactured by Toyobo, polyester rubber)
(2) PNR-1H (trade name) (manufactured by JSR, carboxyl group-containing NBR, high-purity product)
(3) ZP2020 (trade name) (manufactured by Nippon Zeon, hydrogenated NBR)
(C) Curing agent (1) EH705A (trade name) (Asahi Denka, acid anhydride curing agent)
(2) DDS (diamine-based curing agent)
(3) Dicyandiamide (4) KC-01 (manufactured by Konishi Co., Ltd., amine curing agent)
・ (D) Curing accelerator (1) 2E4MZ-CN (trade name) (made by Shikoku Kasei Kogyo Co., Ltd., imidazole curing accelerator)
(2) 2E4MZ (trade name) (made by Shikoku Kasei Kogyo Co., Ltd., imidazole curing accelerator)
(3) 2P4MHZ-PW (trade name) (manufactured by Shikoku Kasei Kogyo Co., Ltd., imidazole curing accelerator)
(E) Phosphorus-containing plasticizer (1) SPE-100 (trade name) (manufactured by Otsuka Chemical, phosphazene compound)
(2) PX-200 (trade name) (manufactured by Daihachi Chemical, phosphate ester compound)
-(F) Inorganic filler (1) Heidilite H43STE (Showa Denko, aluminum hydroxide)
(2) Zinc flower (zinc oxide)
・ (Others) Phosphorus-containing compounds (1) MPP-C (trade name) (manufactured by Sanwa Chemical, melamine phosphate filler)

<Characteristics of flexible copper clad laminate>
[Example 1]
Each component of the adhesive composition was mixed in the proportions shown in the column of Example 1 in Table 1, and the resulting mixture was added to a mixed solvent of methyl ethyl ketone / toluene to obtain a total of the organic resin component and the inorganic solid component. An adhesive solution having a concentration of 35% by mass was prepared.

  On the other hand, one side of polyimide film A (trade name: Kapton V, manufactured by DuPont, thickness: 25 μm) is subjected to predetermined conditions (pressure: 13.3 Pa, argon flow rate: 1.0 L / min, applied voltage: 2 kV, frequency: 110 kHz, power) : 30kW, treatment speed: 10m / min). Next, the adhesive solution was applied to the polyimide film surface with an applicator so that the thickness after drying was 18 μm, and the composition was semi-cured by drying in a blowing oven at 140 ° C. for 10 minutes, This and the treated surface of rolled copper foil (made by Japan Energy, thickness: 35 μm) are thermocompression bonded at 120 ° C, then aftercuring at 80 ° C for 2 hours, 120 ° C for 1 hour, and 160 ° C for 5 hours. As a result, a flexible copper clad laminate was produced. About the characteristic of this flexible copper clad laminated board, it measured according to the following measuring method 1. The results are shown in Table 1.

[Example 2]
Each component of the adhesive composition was mixed in the ratio shown in the column of Example 2 in Table 1, and instead of polyimide film A, polyimide film B (trade name: Apical NPI, manufactured by Kaneka Chemical, thickness: 25 μm) was used. A flexible copper clad laminate was produced in the same manner as in Example 1 except that it was used. About the characteristic of this flexible copper clad laminated board, it measured according to the following measuring method 1. The results are shown in Table 1.

[Comparative Examples 1 and 2]
Flexible copper as in Example 1 except that the components of the adhesive composition were mixed in the proportions shown in the columns of Comparative Examples 1 and 2 in Table 1 and the polyimide film A that was not plasma-treated was used. A tension laminate was produced. The characteristics of these flexible copper clad laminates were measured according to the following measurement method 1. The results are shown in Table 1.

[Measurement method 1]
1-1. Peel strength
In accordance with JIS C6481, after forming a circuit with a pattern width of 1 mm on a flexible copper-clad laminate, the copper foil (the circuit) was peeled off at a rate of 50 mm / min in the direction of 90 degrees at 25 ° C. The peel strength was measured.

1-2. Solder heat resistance (normal)
In accordance with JIS C6481, a test piece is prepared by cutting a flexible copper-clad laminate into 25 mm squares. The test piece is floated on a solder bath for 30 seconds, and the test piece is swollen, peeled off, and discolored. Not the highest temperature measured.

1-3. Flame retardance All copper foil was removed by etching the flexible copper-clad laminate to produce a sample. The flame retardancy of the sample was measured in accordance with UL94VTM-0 flame retardancy standard. When the flame retardancy satisfying the UL94VTM-0 standard was evaluated, it was evaluated as “good” and indicated by ○, and when the sample burned, it was evaluated as “bad” and indicated by ×.

<Characteristics of coverlay film>
[Examples 3 to 6]
An adhesive solution was prepared in the same manner as in Example 1 except that the components of the adhesive composition were mixed in the proportions shown in the respective columns of Examples 3 to 6 in Table 2. On the other hand, the polyimide film B was subjected to low temperature plasma treatment under the same conditions as in Example 1. Next, the adhesive solution is applied to the polyimide film surface with an applicator so that the thickness after drying is 25 μm, and the composition is covered in a semi-cured state by drying in a blowing oven at 140 ° C. for 10 minutes. A lay film was prepared. The characteristics of these coverlay films were measured according to the following measurement method 2. The results are shown in Table 2.

[Comparative Examples 3 and 4]
A coverlay was prepared in the same manner as in Example 3 except that the components of the adhesive composition were mixed in the proportions shown in the respective columns of Comparative Examples 3 and 4 in Table 2 and the polyimide film B which was not plasma-treated was used. A film was prepared. The characteristics of these coverlay films were measured according to the following measurement method 2. The results are shown in Table 2.

[Measurement method 2]
2-1. Peel strength
In accordance with JIS C6481, press machine (temperature: 160 ° C, pressure: 50kg / cm ² , time: 40) with glossy surface of 35μm thick electrolytic copper foil (manufactured by Japan Energy) and cover layer film adhesive layer A press sample was prepared by laminating using a method. However, for the coverlay film obtained in Example 6, the press temperature was 180 ° C. The press sample is cut to a size of 1cm in width, 15cm in length, and 72μm in thickness to make a test piece. The polyimide film surface of the test piece is fixed, and the copper foil is oriented in the direction of 90 degrees at 25 ° C. The peel strength when peeled at a speed of 50 mm / min was measured.

2-2. Solder heat resistance (normal condition, moisture absorption)
Solder heat resistance (normal state) was measured in the same manner as in the above measurement method 1-2, except that a test piece was prepared by cutting a press sample of a coverlay film prepared by measuring the peel strength into 25 mm squares.

  On the other hand, with regard to solder heat resistance (moisture absorption), a test piece prepared in the same manner as that for measuring the solder heat resistance (normal state) was left in an atmosphere of 40 ° C. and 90% humidity for 24 hours, and then the test was performed. The piece was floated on the solder bath for 30 seconds, and the maximum temperature at which the piece was swollen, peeled off and discolored was measured.

2-3. Flame Retardant Pressing the coverlay film obtained in Examples 3 to 6 and the sample adhesive layer from which all the copper foil has been removed by etching the flexible copper clad laminate obtained in Example 2 (Temperature: 160 ° C., pressure: 50 kg / cm ² , time: 30 minutes). Further, in the same manner as in the above method, the coverlay film obtained in Comparative Examples 3 and 4 and the sample from which all the copper foil was removed by etching the flexible copper-clad laminate obtained in Comparative Example 2 A press sample was produced by bonding. About these press samples, the flame retardance (combination with a flexible copper clad laminated board) was evaluated like the said measuring method 1-3.

2-4. Migration resistance A press apparatus (temperature: 160 ° C., pressure: the cover lay film obtained in Examples 3 to 6 and a substrate on which a circuit of 70 μm pitch was printed on the flexible copper-clad laminate obtained in Example 2 were used. 50 kg / cm ² , time: 40 minutes) was used to produce a press sample. Further, in the same manner as described above, the cover lay film obtained in Comparative Examples 3 and 4 was bonded to the substrate on which the circuit of 70 μm pitch was printed on the flexible copper clad laminate obtained in Comparative Example 2. A press sample was prepared. When a voltage of 50V is applied to the circuit of these press samples under the conditions of 85 ° C and 85% humidity, a short circuit occurs between the conductors after 500 hours or dendrite growth is observed. Was evaluated as “x”, and the case where none occurred was evaluated as “good” and indicated as “◯”.

<Evaluation>
The compositions prepared in Examples 1 and 2 satisfy the requirements of the present invention, and the flexible copper clad laminate using the composition was excellent in peel strength, solder heat resistance and flame retardancy. The compositions prepared in Comparative Examples 1 and 2 did not contain (E) a phosphorus-containing plasticizer among the requirements of the present invention, and the polyimide film whose surface was plasma-treated was not used. The obtained flexible copper-clad laminate was inferior to the case where at least one characteristic of peel strength and flame retardancy satisfied the requirements of the present invention.

  The compositions prepared in Examples 3 to 6 satisfy the requirements of the present invention, and the coverlay film using the composition was excellent in peel strength, solder heat resistance, flame resistance, and migration resistance. . Since the composition prepared in Comparative Examples 3 and 4 does not contain (E) a phosphorus-containing plasticizer among the requirements of the present invention and a polyimide film whose surface was plasma-treated was not used, it was obtained. The obtained coverlay film was inferior to the case where at least one characteristic of peel strength, solder heat resistance, flame retardancy and migration resistance satisfied the requirements of the present invention.

The cured product obtained by curing the flame retardant adhesive composition of the present invention, and the coverlay film and flexible copper clad laminate using the composition are all flame retardant, peel strength, electrical properties (resistance to It has excellent migration properties and solder heat resistance, and does not contain halogen, so it is expected to be applied to the production of flexible printed wiring boards that are friendly to the environment.

Claims (8)

(A) non-halogen epoxy resin,
(B) thermoplastic resin and / or synthetic rubber,
(C) a curing agent,
(D) a curing accelerator,
(E) A flame-retardant adhesive composition comprising a phosphorus-containing plasticizer and (F) an inorganic filler.   The component (B) is at least one polymer compound selected from the group consisting of polyester resins, acrylic resins, phenoxy resins, polyamideimide resins, epoxy resins having a weight average molecular weight of 1,000 or more, and carboxyl group-containing acrylonitrile butadiene rubber. The flame-retardant adhesive composition according to claim 1.   The composition according to claim 1 or 2, wherein the component (C) is an acid anhydride and / or a polyamine compound.   (E) A component is a phosphate ester compound and / or a phosphazene compound, The composition as described in any one of Claims 1-3.   The coverlay film which has an electrically insulating film by which the low temperature plasma process was carried out, and the layer which consists of a composition as described in any one of Claims 1-4 provided on this film.   The coverlay film according to claim 5, wherein the electrically insulating film is a polyimide film.   The flexible copper clad laminated board which has an electrically insulating film by which low temperature plasma processing was carried out, the layer which consists of a composition as described in any one of Claims 1-4 provided on this film, and copper foil. The flexible copper clad laminate according to claim 7, wherein the electrically insulating film is a polyimide film.