WO2021124668A1

WO2021124668A1 - Adhesive composition

Info

Publication number: WO2021124668A1
Application number: PCT/JP2020/039263
Authority: WO
Inventors: 航片桐; 栞門間
Original assignee: 信越ポリマー株式会社
Priority date: 2019-12-20
Filing date: 2020-10-19
Publication date: 2021-06-24
Also published as: JPWO2021124668A1; TW202128929A; CN114846104A; TWI784365B; CN114846104B

Abstract

Provided is an adhesive composition from which an adhesive layer having an excellent electrical property and an excellent adhesion (stickiness) after heat and curing can be formed, and with which an adhesion (stickiness) during a laminating process can be further improved, and peeling or lifting of a layer during a temporary fixing or a roll-to-roll operation can be prevented.　The adhesive composition includes: a styrene-based elastomer containing a carboxyl group; a styrene-based elastomer containing no carboxyl group; and an epoxy resin.

Description

Adhesive composition

The present invention relates to an adhesive composition. More specifically, the present invention relates to an adhesive composition that can be used for adhesive applications such as electronic components.

As electronic devices become smaller and lighter, the applications for bonding electronic components and the like are diversifying, and the demand for laminated bodies with an adhesive layer is increasing.
Further, a flexible printed wiring board (hereinafter, also referred to as FPC), which is one of electronic components, needs to process a large amount of data at high speed, and is being supported for high frequencies. It is necessary to reduce the dielectric properties of the components in order to increase the frequency of the FPC, and low-dielectric base films and low-dielectric adhesives are being developed.

However, low-dielectric adhesives have low molecular polarity, so it is difficult to develop adhesion (adhesiveness) to base films, metal layers, and other components related to electronic components, and low-dielectric base films. Similarly, the adhesion (adhesiveness) with the adhesive may be poor.
Therefore, in order to respond to high adhesiveness while having good electrical characteristics (low relative permittivity and low dielectric tangent), adhesion containing a carboxy group-containing styrene elastomer (A) and an epoxy resin (B). A proposal has been made for a laminate composed of an adhesive layer composed of the adhesive composition and a base film using the agent composition (see, for example, Patent Document 1).

International Publication No. 2016/017473

However, although the adhesive composition described in Patent Document 1 exhibits high adhesion (adhesiveness) after heat curing, for example, when it is used in a laminating step with a short heating time in a laminating body manufacturing step. Was found to be poorly adherent to the substrate film and other components related to electronic components.
If the adhesive composition is not sufficiently adhered to the base film and other components related to electronic components in the laminating process, temporary fixing during thermocompression bonding in the production of the laminated body may occur. Layer peeling and floating occur during roll-to-roll work. As a result, various problems occur in the laminated body, such as a stacking defect or a gap due to fine irregularities generated between the layers, which causes swelling of the layer in the subsequent heating step.

Therefore, the present invention is an adhesive composition capable of forming an adhesive layer having excellent electrical characteristics and excellent adhesion (adhesiveness) after heat curing, and further, the adhesive composition in the laminating step (adhesiveness). It is an object of the present invention to provide an adhesive composition capable of improving (property) and preventing temporary fixing and peeling and floating of layers during roll-to-roll work.

As a result of intensive research to solve the above problems, the present inventors have conducted an adhesive containing at least three components of a carboxy group-containing styrene elastomer, a carboxy group-free styrene elastomer, and an epoxy resin. Not only can the composition exhibit high adhesion (adhesiveness) to the base film after heat curing, but also sufficient adhesion (adhesiveness) to the base film can be exhibited in the laminating step. We have found that the above problems can be solved, and have completed the present invention.

The present invention includes the following aspects.
[1] An adhesive composition containing a styrene-based elastomer containing a carboxy group, a styrene-based elastomer not containing a carboxy group, and an epoxy resin.
[2] The adhesive composition according to [1], wherein the content of the epoxy resin is 1 to 20 parts by mass with respect to 100 parts by mass of the adhesive composition.
[3] The adhesive composition according to [1] or [2], wherein the content of the styrene-based elastomer containing the carboxy group is less than 50 parts by mass with respect to 100 parts by mass of the adhesive composition.
[4] The adhesive composition according to any one of [1] to [3], wherein the epoxy resin has a softening point or a melting point of 90 ° C. or lower.
[5] The adhesive composition according to any one of [1] to [4], which further contains an organic peroxide.
[6] An adhesive layer composed of the adhesive composition according to any one of [1] to [5], wherein the storage elastic modulus at 120 ° C. before curing of the adhesive layer is 5 × 10 ⁵ Pa. The adhesive layer below.
[7] An adhesive layer composed of the adhesive composition according to any one of [1] to [5], wherein the storage elastic modulus at 25 ° C. after curing of the adhesive layer is 8 × 10 ⁷ Pa. That is the adhesive layer.
[8] With respect to the adhesive layer obtained by curing the adhesive composition according to any one of [1] to [5], the relative permittivity of the adhesive layer measured at a frequency of 28 GHz is 3.5 or less. An adhesive layer that is present and has a dielectric loss tangent of 0.01 or less.
[9] Base film and
A laminate having an adhesive layer composed of the adhesive composition according to any one of [1] to [5] or an adhesive layer according to any one of [6] to [8].
[10] The laminate according to [9], wherein the base film contains a polyetheretherketone (PEEK) resin.
[11] A coverlay film with an adhesive layer containing the laminate according to [9] or [10].
[12] A copper-clad laminate containing the laminate according to [9] or [10].
[13] A printed wiring board containing the laminate according to [9] or [10].
[14] A shield film containing the laminate according to [9] or [10].
[15] A printed wiring board with a shield film containing the laminate according to [9] or [10].

According to the present invention, the adhesive composition has excellent electrical properties and can form an adhesive layer having excellent adhesion (adhesiveness) after heat curing, and further adheres (adhesiveness) in the laminating step. It is possible to provide an adhesive composition capable of improving (property) and preventing temporary fixing and peeling and floating of layers during roll-to-roll work.

Hereinafter, the adhesive composition of the present invention, a laminate containing an adhesive layer composed of the adhesive composition, and components related to electronic components including the laminate will be described in detail, but the constituent requirements described below will be described. The description of the above is an example as an embodiment of the present invention, and is not specified in these contents.

(Adhesive composition)
The adhesive composition of the present invention contains a styrene-based elastomer containing a carboxy group, a styrene-based elastomer not containing a carboxy group, and an epoxy resin. The adhesive composition of the present invention may contain other components, if necessary.

<Styrene-based elastomer containing carboxy group>
The styrene-based elastomer containing a carboxy group is effective as a component that imparts electrical properties in addition to adhesiveness and flexibility of the cured product.
Since the adhesive composition contains a styrene-based elastomer containing a carboxy group, a flexible adhesive composition can be formed on the surface of the base film even if the base film has good electrical characteristics and low polarity. By being able to sufficiently follow, the low-polarity skeleton can develop adhesion, and even in the case of a metal layer, the highly polar carboxy group can develop adhesion, so that the adhesion of the adhesive layer is improved. Further, since the styrene-based elastomer containing a carboxy group is reactive, the heat resistance and chemical resistance of the adhesive layer are improved by epoxy curing.
The styrene-based elastomer containing a carboxy group is a copolymer mainly composed of a block of a conjugated diene compound and an aromatic vinyl compound and a random structure, and a hydrogenated product thereof modified with an unsaturated carboxylic acid. ..
Examples of the aromatic vinyl compound include styrene, t-butylstyrene, α-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N, N-diethyl-p-aminoethylstyrene, vinyltoluene and the like. Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like.

Modification of the styrene-based elastomer containing a carboxy group can be performed, for example, by copolymerizing an unsaturated carboxylic acid at the time of polymerization of the styrene-based elastomer. It can also be carried out by heating and kneading a styrene-based elastomer and an unsaturated carboxylic acid in the presence of an organic peroxide.
Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, maleic anhydride, and itaconic anhydride.
The amount of modification with unsaturated carboxylic acid is preferably 0.1 to 10% by mass.
The acid value of the styrene-based elastomer containing a carboxy group is preferably 0.1 to 30 mgKOH / g, and more preferably 0.5 to 25 mgKOH / g. When this acid value is 0.1 mgKOH / g or more, the adhesive composition is sufficiently cured, and good adhesiveness and heat resistance can be obtained. On the other hand, when the acid value is 25 mgKOH / g or less, the cohesive force of the adhesive composition is suppressed, so that the adhesiveness is excellent and the electrical characteristics are also excellent.

The weight average molecular weight of the styrene-based elastomer containing a carboxy group is preferably 10,000 to 500,000, more preferably 30,000 to 300,000, and even more preferably 50,000 to 200,000. When the weight average molecular weight is at least the above lower limit, excellent adhesiveness can be exhibited, and the coatability when dissolved in a solvent and coated is also improved. When the weight average molecular weight is not more than the above upper limit, the compatibility with the epoxy resin is improved.
The weight average molecular weight is a polystyrene-equivalent value of the molecular weight measured by gel permeation chromatography (hereinafter, also referred to as “GPC”).

Specific examples of the styrene-based elastomer containing a carboxy group include a styrene-butadiene block copolymer, a styrene-ethylene propylene block copolymer, a styrene-butadiene-styrene block copolymer, and a styrene-isoprene-styrene block copolymer. , Styrene-ethylenebutylene-styrene block copolymer, styrene-ethylenepropylene-styrene block copolymer and the like modified with unsaturated carboxylic acid.
Only one kind of these carboxy group-containing styrene-based elastomers may be used, or two or more kinds may be used in combination. Among the above copolymers, styrene-ethylenebutylene-styrene block copolymers and styrene-ethylenepropylene-styrene block copolymers are preferable from the viewpoint of adhesiveness and electrical properties. The mass ratio of styrene / ethylenebutylene in the styrene-ethylenebutylene-styrene block copolymer and the mass ratio of styrene / ethylenepropylene in the styrene-ethylenepropylene-styrene block copolymer are 10/90 to 50/50. It is preferably 20/80 to 40/60, and more preferably 20/80 to 40/60. When the mass ratio is within this range, an adhesive composition having excellent adhesive properties can be obtained.

The content of the styrene-based elastomer containing a carboxy group is preferably less than 50 parts by mass with respect to 100 parts by mass of the solid content of the adhesive composition. If the content of the styrene-based elastomer containing a carboxy group is large, it is not possible to improve the adhesion (adhesiveness) in the laminating process.

<Styrene-based elastomer that does not contain carboxy groups>
Compared to the above-mentioned styrene-based elastomer containing a carboxy group, the styrene-based elastomer containing no carboxy group has a smaller cohesive force due to the absence of interaction of the carboxy group, and has a lower elastic modulus in a high temperature region than the glass transition point. Therefore, since the adhesive composition contains a styrene-based elastomer that does not contain a carboxy group, the adhesiveness of the adhesive layer is improved, and in particular, the adhesiveness (adhesiveness) in the laminating process can be improved. it can.
The styrene-based elastomer containing no carboxy group is a copolymer mainly composed of a block and a random structure of a conjugated diene compound and an aromatic vinyl compound, and a hydrogenated product thereof. Such elastomers have not been modified with unsaturated carboxylic acids.
The types of aromatic vinyl compounds and conjugated diene compounds constituting the styrene-based elastomer, or specific examples of the styrene-based elastomer are as described in the above section <Styrene-based elastomer containing a carboxy group>.

The content of the styrene-based elastomer containing no carboxy group is preferably 30 parts by mass to 70 parts by mass with respect to 100 parts by mass of the solid content of the adhesive composition. When the content of the styrene-based elastomer containing no carboxy group is at least the above lower limit value, the adhesion (adhesiveness) in the laminate is improved. On the other hand, if it is not more than the above upper limit value, a component to be cured can be sufficiently blended, and heat resistance can be ensured.

<Epoxy resin>
The epoxy resin is a component that reacts with the carboxy group in the styrene-based elastomer containing the carboxy group to develop high adhesiveness to the adherend and heat resistance of the cured adhesive.

Examples of epoxy resins are bisphenol A type epoxy resin, bisphenol F type epoxy resin, or hydrogenated bisphenol F type epoxy resin; phthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p-hydroxybenzoic acid. Glycidyl ester-based epoxy resins such as glycidyl ester, tetrahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, trimellitic acid triglycidyl ester; ethylene glycol diglycidyl ether, propylene glycol Diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylpropan triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenylglycidyl ether ethane, triphenylglycidyl ether ethane, sorbitol Glycidyl ether-based epoxy resins such as polyglycidyl ether and polyglycerol polyglycidyl ether; glycidyl amine-based epoxy resins such as triglycidyl isocyanurate and tetraglycidyl diaminodiphenylmethane; linear aliphatics such as epoxidized polybutadiene and epoxidized soybean oil. Epoxy resins and the like can be mentioned, but the present invention is not limited to these. Further, novolac type epoxy resins such as xylene structure-containing novolac epoxy resin, naphthol novolac type epoxy resin, phenol novolac epoxy resin, o-cresol novolac epoxy resin, and bisphenol A novolac epoxy resin can also be used.

Further, as an example of the epoxy resin, brominated bisphenol A type epoxy resin, phosphorus-containing epoxy resin, fluorine-containing epoxy resin, dicyclopentadiene skeleton-containing epoxy resin, naphthalene skeleton-containing epoxy resin, anthracene-type epoxy resin, tertiary butyl catechol-type epoxy Resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, biphenyl type epoxy resins, bisphenol S type epoxy resins and the like can be used. Only one type of these epoxy resins may be used, or two or more types may be used in combination.
Among the above epoxy resins, an epoxy resin having no hydroxyl group is preferable because an adhesive composition having excellent electrical characteristics can be obtained and compatibility with a styrene-based elastomer is good. In particular, since novolak epoxy resin and epoxy resin having the following structure have an appropriately flexible skeleton, the cured product is less likely to cause brittle fracture, and the performance of the cured product of the adhesive composition is stable for long-term use. It is more preferable because the property is improved and the number of functional groups is high, so that the heat resistance is also improved.

(R is a structure containing methylene-aryl-methylene or a structure containing an aliphatic hydrocarbon structure having 6 or more carbon atoms, and examples of aryl include benzene, xylene, naphthalene, biphenyl, etc., and examples of the aryl are aliphatic hydrocarbons. Includes hexane, dimethylcyclohexane, dicyclopentadiene, etc.)
Specific examples of the novolac type epoxy resin include "YX7700" manufactured by Mitsubishi Chemical Co., Ltd. (novolac type epoxy resin containing a xylene structure), "NC7000L" manufactured by Nippon Kayaku Co., Ltd. (naphthol novolac type epoxy resin), and the like. "ESN485" (naphthol novolac type epoxy resin) manufactured by Nittetsu Chemical & Materials Co., Ltd., "N-690" (cresol novolac type epoxy resin) manufactured by DIC Co., Ltd., "N-695" manufactured by DIC Co., Ltd. ( Cresol novolac type epoxy resin) and the like.

Further, the epoxy resin having an amino group can shorten the curing time and lower the curing temperature by the catalytic action of the amino group, so that the workability can be improved. Further, since it contains an amine group, the adhesion to the metal layer is improved.
In particular, it is more preferable that the epoxy resin is a glycidylamine type epoxy resin. Since the glycidylamine type epoxy resin is polyfunctional, it can be cured with a small amount, and since it contains an amine in its molecular skeleton, it has good compatibility with an amino group-containing styrene-based elastomer and also has a reaction promoting effect. Further, since it contains an amine group, the adhesion to the metal layer can be improved.
Specific examples of the glycidylamine type epoxy resin include, as tetraglycidyldiaminodiphenylmethane, "jER604" manufactured by Mitsubishi Chemical Co., Ltd., "Sumiepoxy ELM434" manufactured by Sumitomo Chemical Co., Ltd., and Huntsman Advanced Materials Co., Ltd. "Araldite MY720", "Araldite MY721", "Araldite MY9512", "Araldite MY9612", "Araldite MY9634", "Araldite MY9663", "TETRAD-X", "TETRAD-C" manufactured by Mitsubishi Gas Chemical Company, Ltd. Can be mentioned.

The epoxy resin used in the present invention is preferably one having two or more epoxy groups in one molecule. This is because a crosslinked structure can be formed by reaction with a styrene-based elastomer containing a carboxy group, and high heat resistance can be exhibited. Further, when an epoxy resin having two or more epoxy groups is used, the degree of cross-linking with the carboxy group-containing styrene-based elastomer is sufficient, and sufficient heat resistance can be obtained.

The content of the epoxy resin is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the solid content of the adhesive composition. When the content of the epoxy resin is at least the above lower limit value, the adhesive composition is sufficiently cured, and good heat resistance and chemical resistance can be ensured. On the other hand, if the content of the epoxy resin is large, the adhesiveness is lowered, and therefore, if it is equal to or less than the above upper limit value, good adhesion can be ensured. If the content of the epoxy resin is large, it is not possible to improve the adhesiveness (adhesiveness) in the laminating process.

The softening point or melting point of the epoxy resin is preferably 90 ° C. or lower. When the softening point or melting point of the epoxy resin is 90 ° C. or lower, the elastic modulus of the adhesive composition before curing in the high temperature range is lowered, and the elastic modulus of the adhesive composition after curing in the normal temperature range (room temperature) is increased. Can be raised.

<Other ingredients>
The adhesive composition includes the above-mentioned carboxy group-containing styrene elastomer, carboxy group-free styrene elastomer, and epoxy resin, as well as carboxy group-containing styrene elastomer and carboxy group-free styrene elastomer. Other thermoplastic resins other than elastomers, tackifiers, flame retardants, curing agents, curing accelerators, coupling agents, heat aging inhibitors, leveling agents, defoaming agents, inorganic fillers, pigments, solvents, etc. It can be contained to the extent that it does not affect the function of the adhesive composition.

A more preferred embodiment of the adhesive composition containing other components includes, for example, an adhesive composition containing an organic peroxide. As a result, the styrene-based elastomer containing no carboxy group can also be crosslinked, and the heat resistance and chemical resistance of the adhesive layer can be further improved.
As the organic peroxide, those generally known as radical polymerization initiators can be used, for example, benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, t-butylperoxyethyl hexanoate, 1,1. Examples thereof include organic peroxides such as'-bis- (t-butylperoxy) cyclohexane, t-amylperoxy-2-ethylhexanoate, and t-hexylperoxy-2-ethylhexanoate.

Among the other components, the other thermoplastic resins include, for example, phenoxy resin, polyamide resin, polyester resin, polycarbonate resin, polyphenylene oxide resin, polyurethane resin, polyacetal resin, polyethylene resin, polypropylene resin and polyvinyl resin. Examples include resin. These thermoplastic resins may be used alone or in combination of two or more.

Examples of the tackifier include kumaron-inden resin, terpene resin, terpene-phenol resin, rosin resin, pt-butylphenol-acetylene resin, phenol-formaldehyde resin, xylene-formaldehyde resin, and petroleum hydrocarbon resin. Examples thereof include hydrogenated hydrocarbon resins and terpene resins. These tackifiers may be used alone or in combination of two or more.

The flame retardant may be either an organic flame retardant or an inorganic flame retardant. Examples of the organic flame retardant include melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium phosphate, ammonium polyphosphate, carbamate phosphate, and carbamate polyphosphate. , Aluminum Trisdiphenylphosphinate, Aluminum Trismethylethylphosphite, Aluminum Trisdiphenylphosphinate, Zinc bisdiphenylphosphinate, Zinc bismethylethylphosphine, Zinc bisdiphenylphosphite, Titanyl bisdiphenylphosphite, Titanium tetrakisdiethylphosphine Phosphate-based flame retardants such as titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate, titanium tetraxidiphenylphosphinate; triazine compounds such as melamine, melam, and melamine cyanurate, and cyanuric acid compounds. , Isocyanuric acid compound, triazole compound, tetrazole compound, diazo compound, urea and other nitrogen-based flame retardant; silicone compound, silane compound and other silicon-based flame retardant. Examples of the inorganic flame retardant include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, and calcium hydroxide; tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, and zinc oxide. Metal oxides such as molybdenum oxide and nickel oxide; zinc carbonate, magnesium carbonate, barium carbonate, zinc borate, hydrated glass and the like can be mentioned. Two or more of these flame retardants can be used in combination.

Examples of the curing agent include, but are not limited to, amine-based curing agents and acid anhydride-based curing agents. Examples of the amine-based curing agent include melamine resins such as methylated melamine resin, butylated melamine resin and benzoguanamine resin, dicyandiamide, and 4,4'-diphenyldiaminosulfone. Examples of the acid anhydride include aromatic acid anhydrides and aliphatic acid anhydrides. These curing agents may be used alone or in combination of two or more.
The content of the curing agent is preferably 0.5 to 100 parts by mass and more preferably 5 to 70 parts by mass with respect to 100 parts by mass of the adhesive composition.

The above-mentioned curing accelerator is used for the purpose of accelerating the reaction between the styrene-based elastomer containing a carboxy group and the epoxy resin, and is a tertiary amine-based curing accelerator, a tertiary amine salt-based curing accelerator, and a tertiary amine salt-based curing accelerator. An imidazole-based curing accelerator or the like can be used.

Examples of the tertiary amine-based curing accelerator include benzyldimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, tetramethylguanidine, triethanolamine, N, N'. -Dimethylpiperazine, triethylenediamine, 1,8-diazabicyclo [5.4.0] undecene and the like can be mentioned.

As a tertiary amine salt-based curing accelerator, 1,8-diazabicyclo [5.4.0] undecene, formate, octylate, p-toluenesulfonate, o-phthalate, phenol salt or Phenol novolak resin salt and 1,5-diazabicyclo [4.3.0] nonene, formate, octylate, p-toluenesulfonate, o-phthalate, phenol salt, phenol novolak resin salt, etc. Can be mentioned.

Examples of the imidazole-based curing accelerator include 2-methylimidazole, 2-undecyl imidazole, 2-heptadecyl imidazole, 1,2-dimethyl imidazole, 2-methyl-4-ethyl imidazole, 2-phenyl imidazole, and 2-phenyl-. 4-Methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2,4-diamino-6- [2'-methylimidazolyl- (1')] ethyl-s-triazine, 2 , 4-Diamino-6- [2'-undecylimidazolyl- (1')] ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1')) ] Ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')] ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl- Examples thereof include 4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole. These curing accelerators may be used alone or in combination of two or more.

When the adhesive composition contains a curing accelerator, the content of the curing accelerator is preferably 0.05 to 10 parts by mass and 0.1 to 5 parts by mass with respect to 100 parts by mass of the adhesive composition. More preferably, it is by mass. When the content of the curing accelerator is within the above range, the reaction between the styrene-based elastomer containing a carboxy group and the epoxy resin and the reaction between the epoxy resins can easily proceed, and the adhesiveness and heat resistance can be easily ensured. ..

Examples of the coupling agent include vinyl trimethoxysilane, 3-glycidoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, and N. -2- (Aminoethyl) -3-aminopropylmethyldimethoxyloxylan, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isosianetpropyltri Examples thereof include silane-based coupling agents such as ethoxysilane and imidazole silane; titanate-based coupling agents; aluminum-based coupling agents; zirconium-based coupling agents and the like. These may be used alone or in combination of two or more.

Examples of the heat antiaging agent include 2,6-di-tert-butyl-4-methylphenol and n-octadecyl-3- (3', 5'-di-tert-butyl-4'-hydroxyphenyl) propione. -T, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-) Phenol-based antioxidants such as hydroxyphenol, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate; dilauryl-3,3'-thiodipropionate, dimyristyl Sulfur-based antioxidants such as -3,3'-dithiopropionate; phosphorus-based antioxidants such as trisnonylphenyl phosphite and tris (2,4-di-tert-butylphenyl) phosphite can be mentioned. These may be used alone or in combination of two or more.

Examples of the inorganic filler include powders made of titanium oxide, aluminum oxide, zinc oxide, carbon black, silica, talc, copper, silver and the like. These may be used alone or in combination of two or more.

(Adhesive layer)
The adhesive layer of the present invention comprises the above-mentioned adhesive composition of the present invention.
The adhesive composition forming the adhesive layer can be cured.
The curing method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include thermosetting.
The thickness of the adhesive layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, it is preferably 3 to 100 μm, more preferably 5 to 70 μm, and 10 to 50 μm. Is even more preferable.

<Manufacturing method of adhesive layer>
An adhesive layer can be produced by forming the above-mentioned adhesive composition into a film.
The adhesive composition can be produced by mixing a styrene-based elastomer containing a carboxy group, a styrene-based elastomer not containing a carboxy group, an epoxy resin, and other components. The mixing method is not particularly limited, and the adhesive composition may be uniform. Since the adhesive composition is preferably used in the state of a solution or a dispersion, a solvent is also usually used.
Examples of the solvent include alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutyl alcohol, n-butyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diacetone alcohol. ; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, mesitylene; methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, Esters such as 3-methoxybutyl acetate; aliphatic hydrocarbons such as hexane, heptane, cyclohexane, methylcyclohexane and the like can be mentioned. These solvents may be used alone or in combination of two or more.
When the adhesive composition is a solution containing a solvent or a dispersion liquid (resin varnish), coating on the base film and formation of the adhesive layer can be smoothly performed, and an adhesive layer having a desired thickness can be obtained. It can be easily obtained.
When the adhesive composition contains a solvent, the solid content concentration is preferably in the range of 3 to 80% by mass, more preferably 10 to 50% by mass, from the viewpoint of workability including formation of the adhesive layer. When the solid content concentration is 80% by mass or less, the viscosity of the solution is appropriate and it is easy to apply the solution uniformly.
As a more specific embodiment of the method for producing an adhesive layer, a resin varnish containing the adhesive composition and a solvent is applied to the surface of a base film to form a resin varnish layer, and then the resin varnish is formed. By removing the solvent from the layer, a B-stage adhesive layer can be formed. Here, the B-stage shape of the adhesive layer means an uncured state or a semi-cured state in which a part of the adhesive composition has begun to cure, and the curing of the adhesive composition further progresses by heating or the like. The state of doing.
Here, the method of applying the resin varnish on the base film is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a spray method, a spin coating method, a dip method, a roll coating method, etc. Examples thereof include a blade coating method, a doctor roll method, a doctor blade method, a curtain coating method, a slit coating method, a screen printing method, an inkjet method, and a dispensing method.
The B-stage adhesive layer can be further heated or the like to form a cured adhesive layer.

<Characteristics of adhesive layer>
The adhesive layer of the present invention preferably has a storage elastic modulus of 1 × 10 ³ Pa or more and 5 × 10 ⁵ Pa or less at 120 ° C. before curing.
When the storage elastic modulus is 5 × 10 ⁵ Pa or less, the storage elastic modulus is low at the temperature during the laminating process, so that the adhesive layer easily adheres to the base film and other components related to electronic components. ..

[Storage modulus (Pa)]
For the storage elastic modulus of the adhesive layer, for example, for a sample composed of the adhesive layer, an adhesive film having a thickness of 100 μm was prepared, and a viscoelasticity measuring device (RSA-G2 manufactured by TA Instruments) was used, and the measurement frequency was increased to 1 Hz. Obtained by measurement according to JIS K7244 under the condition of a temperature rate of 5 ° C./min.

The adhesive layer of the present invention preferably has a storage elastic modulus at 25 ° C. after curing of 8 × 10 ⁷ Pa or more and 5 × 10 ⁹ Pa or less.
When the storage elastic modulus is 8 × 10 7 ^Pa or higher, because of high storage elastic modulus at room temperature, the adhesive layer can retain adhesion to the substrate film and electronic components associated other component.

The adhesive layer of the present invention obtained by curing the adhesive composition has a relative permittivity (εr) of 3.5 or less and a dielectric loss tangent (tan δ) of 0.01 as measured at a frequency of 28 GHz. The following is preferable.
When the relative permittivity is 3.5 or less and the dielectric loss tangent is 0.01 or less, it can be suitably used for FPC-related products having strict requirements for electrical characteristics.

[Relative permittivity and dielectric loss tangent]
For the relative permittivity and dielectric loss tangent of the adhesive layer, a network analyzer MS46122B (manufactured by Anritsu) and an open resonator Fabry Perot DPS-03 (manufactured by KEYCOM) are used, and the temperature is 23 ° C. by the open resonator method. , Can be measured under the condition of a frequency of 28 GHz.

(Laminated body)
The laminate of the present invention includes a base film and the adhesive layer on at least one surface of the base film.

<Base film>
The base film used in the present invention can be selected depending on the intended use of the laminate. For example, when the laminate is used as a coverlay film or a copper-clad laminate (CCL), examples thereof include a polyimide film, a polyetheretherketone film, a polyphenylene sulfide film, an aramid film, a polyethylene naphthalate film, and a liquid crystal polymer film. .. Among these, a polyimide film, a polyetheretherketone (PEEK) film, a polyethylene naphthalate film, and a liquid crystal polymer film are preferable from the viewpoint of adhesiveness and electrical properties.

When the laminate of the present invention is used as a bonding sheet, the base film must be a releasable film, for example, polyethylene terephthalate film, polyethylene film, polypropylene film, silicone releasable paper, polyolefin resin. Examples thereof include coated paper, TPX (polymethylpentene) film, and fluororesin film.

When the laminate of the present invention is used as a shield film, the base film needs to be a film having an electromagnetic wave shielding ability, and examples thereof include a laminate of a protective insulating layer and a metal foil.

(Coverlay film)
A coverlay film is mentioned as a preferable embodiment of the laminate according to the present invention.
When manufacturing an FPC, a laminate having an adhesive layer called a "coverlay film" is usually used to protect the wiring portion. This coverlay film includes an insulating resin layer and an adhesive layer formed on the surface thereof.
For example, the coverlay film is a laminate in which the adhesive layer is formed on at least one surface of the base film, and it is generally difficult to peel off the base film and the adhesive layer.
The thickness of the base film contained in the coverlay film is preferably 5 to 100 μm, more preferably 5 to 50 μm, and even more preferably 5 to 30 μm. When the thickness of the base film is not more than the above upper limit, the coverlay film can be thinned. When the thickness of the base film is at least the above lower limit, the printed wiring board can be easily designed and handled well.
As a method for producing a coverlay film, for example, a resin varnish containing the adhesive composition and a solvent is applied to the surface of the base film to form a resin varnish layer, and then a solvent is used from the resin varnish layer. By removing the above, it is possible to produce a coverlay film on which a B-stage-shaped adhesive layer is formed.
The drying temperature at the time of removing the solvent is preferably 40 to 250 ° C, more preferably 70 to 170 ° C.
The drying is carried out by passing the laminate coated with the adhesive composition through a furnace in which hot air drying, far-infrared heating, high-frequency induction heating and the like are performed.
If necessary, a releasable film may be laminated on the surface of the adhesive layer for storage or the like. As the releasable film, known films such as polyethylene terephthalate film, polyethylene film, polypropylene film, silicone releasable paper, polyolefin resin coated paper, TPX film, and fluororesin film are used.
Since the coverlay film according to the present invention uses the low-dielectric adhesive composition of the present invention, high-speed transmission of electronic devices is possible, and the adhesive stability with electronic devices is also excellent. Become.

(Bond sheet)
A bonding sheet is mentioned as a preferable embodiment of the laminate according to the present invention.
The bonding sheet has the adhesive layer formed on the surface of the releasable film (base film). Further, the bonding sheet may be in a mode in which an adhesive layer is provided between the two releasable films. When using the bonding sheet, peel off the releasable film before use. As the releasable film, the same one as described in the above (Coverlay film) column can be used.
The thickness of the base film contained in the bonding sheet is preferably 5 to 100 μm, more preferably 25 to 75 μm, and even more preferably 38 to 50 μm. When the thickness of the base film is within the above range, the bonding sheet can be easily manufactured and can be handled well.
As a method for producing the bonding sheet, for example, there is a method in which a resin varnish containing the adhesive composition and the solvent is applied to the surface of the releasable film and dried in the same manner as in the case of the coverlay film.
Since the bonding sheet according to the present invention uses the low-dielectric adhesive composition of the present invention, high-speed transmission of electronic devices is possible, and the adhesive stability with electronic devices is also excellent. ..

(Copper-clad laminate (CCL))
A preferred embodiment of the laminate according to the present invention is a copper-clad laminate in which a copper foil is bonded to an adhesive layer in the laminate of the present invention.
A copper foil is bonded to the copper-clad laminate using the above-mentioned laminate, and for example, a base film, an adhesive layer, and a copper foil are formed in this order. The adhesive layer and the copper foil may be formed on both sides of the base film.
The adhesive composition used in the present invention is also excellent in adhesiveness to articles containing copper.
Since the copper-clad laminate according to the present invention uses the low-dielectric adhesive composition of the present invention, it enables high-speed transmission of electronic devices and has excellent adhesive stability.

As a method for producing a copper-clad laminate, for example, the adhesive layer of the laminate is brought into surface contact with a copper foil, heat-laminated at 80 ° C. to 150 ° C., and the adhesive layer is further cured by aftercure. There is a way. The aftercure conditions can be, for example, 100 ° C. to 200 ° C. for 30 minutes to 4 hours in an atmosphere of an inert gas. The copper foil is not particularly limited, and electrolytic copper foil, rolled copper foil, and the like can be used.

(Printed wiring board)
A preferred embodiment of the laminate according to the present invention is a printed wiring board in which copper wiring is bonded to an adhesive layer in the laminate of the present invention.
The printed wiring board is obtained by forming an electronic circuit on the copper-clad laminate.
In the printed wiring board, the base film and the copper wiring are bonded to each other using the above-mentioned laminate, and the base film, the adhesive layer, and the copper wiring are configured in this order. The adhesive layer and the copper wiring may be formed on both sides of the base film.
For example, a printed wiring board is manufactured by attaching a coverlay film to a surface having a wiring portion via an adhesive layer using a hot press or the like.
Since the printed wiring board according to the present invention uses the low-dielectric adhesive composition of the present invention, it enables high-speed transmission of electronic devices and has excellent adhesive stability.
As a method for manufacturing a printed wiring board according to the present invention, for example, the adhesive layer of the laminated body and the copper wiring are brought into contact with each other, heat-laminated at 80 ° C. to 150 ° C., and the adhesive layer is further cured by after-curing. There is a way to cure. The aftercure conditions can be, for example, 100 ° C. to 200 ° C., 30 minutes to 4 hours. The shape of the copper wiring is not particularly limited, and the shape or the like may be appropriately selected as desired.

(Shield film)
A shield film is mentioned as a preferable embodiment of the laminate according to the present invention.
The shield film is a film for shielding various electronic devices in order to cut electromagnetic noise that affects various electronic devices such as computers, mobile phones, and analytical devices and causes malfunctions. Also called an electromagnetic wave shield film.
The electromagnetic wave shielding film is formed by laminating, for example, an insulating resin layer, a metal layer, and an adhesive layer of the present invention in this order.
Since the shield film according to the present invention uses the low-dielectric adhesive composition of the present invention, high-speed transmission of electronic devices is possible, and the adhesive stability with electronic devices is also excellent. ..

(Printed wiring board with shield film)
A preferred embodiment of the laminate according to the present invention is a printed wiring board with a shield film.
The printed wiring board with a shield film is a printed wiring board provided with a printed circuit on at least one side of the substrate, on which the electromagnetic wave shielding film is attached.
The printed wiring board with a shield film has, for example, a printed wiring board, an insulating film adjacent to the surface of the printed wiring board on the side where the printed circuit is provided, and the electromagnetic wave shielding film.
Since the printed wiring board with a shield film according to the present invention uses the low-dielectric adhesive composition of the present invention, it enables high-speed transmission of electronic devices and has excellent adhesive stability.

The present invention will be described in more detail with reference to Examples below, but the scope of the present invention is not limited to these Examples. In the following, parts and% are based on mass unless otherwise specified.

(Styrene-based elastomer containing carboxy group)
The trade name "Tough Tech M1911" (maleic acid-modified styrene-ethylenebutylene-styrene block copolymer) manufactured by Asahi Kasei Co., Ltd. was used. The acid value of this copolymer is 2 mgKOH / g, the styrene / ethylene butylene ratio is 30/70, and the weight average molecular weight is 69,000.
(Styrene-based elastomer that does not contain a carboxy group)
The trade name "Tough Tech P1500" (hydrogenated styrene elastomer) manufactured by Asahi Kasei Corporation was used. The acid value of this copolymer is 0 mgKOH / g, the styrene / ethylene butylene ratio is 30/70, and the weight average molecular weight is 67,000.
(Epoxy resin)
The trade name "YX7700" (epoxy resin, softening point 65 ° C.) manufactured by Mitsubishi Chemical Corporation was used.
(Perbutyl E)
As the organic peroxide, the trade name "Perbutyl E", which is a peroxy ester manufactured by NOF CORPORATION, was used.
(solvent)
A mixed solvent composed of toluene and methyl ethyl ketone (mass ratio = 90:10) was used.
(Base film)
As the base film, "Shin-Etsu Sepla Film PEEK" (polyetheretherketone, thickness 50 μm) manufactured by Shin-Etsu Polymer Co., Ltd. was used.
(Electrolytic copper foil)
As the electrolytic copper foil, "TQ-M7-VSP" (electrolytic copper foil, thickness 12 μm, glossy surface Rz 1.27 μm, glossy surface Ra 0.197 μm, glossy surface Rsm 12.95 μm) manufactured by Mitsui Mining & Smelting Co., Ltd. was used. The surface roughness of the glossy surface is a value obtained by measuring a roughness curve using a laser microscope and obtaining from this roughness curve based on JIS B 0601: 2013 (ISO 4287: 1997 Amd.1: 2009). ..
(Release film)
As the release film, NP75SA (silicone release PET film, 50 μm) manufactured by Panac Co., Ltd. was used.

(Example 1)
Each component constituting the adhesive layer shown in Table 1 was contained in the ratio shown in Table 1, and these components were dissolved in a solvent to prepare a resin varnish having a solid content concentration of 20% by mass.
The surface of the base film was corona-treated.
The resin varnish was applied to the surface of the base film and dried in an oven at 110 ° C. for 4 minutes to volatilize toluene to form an adhesive layer, and a base film with an adhesive was obtained. The adhesive layer of the adhesive laminate was laminated so as to be in contact with the glossy surface of the electrolytic copper foil, and heat-laminated at 120 ° C. to obtain a pre-cured adhesive laminate. The adhesive layer was cured by further curing the pre-cured adhesive laminate at 150 ° C. for 60 minutes to obtain a post-cured adhesive laminate.
The adhesion (N / cm) between the electrolytic copper foil of the pre-curing adhesive laminate and the post-curing adhesive laminate of Example 1 and the base film was measured.

[Adhesion (N / cm)]
Adhesive strength is such that the pre-cured adhesive laminate and the post-cured adhesive laminate are cut to form a test body with a width of 25 mm, and the peeling speed is 0, in accordance with JIS Z0237: 2009 (adhesive tape / adhesive sheet test method). The adhesive force was measured by measuring the peeling strength when peeling the electrolytic copper foil from the base film with an adhesive fixed to the support at a peeling angle of 180 ° at 3 m / min.

Further, the storage elastic modulus (Pa) at 120 ° C. before curing and the storage elastic modulus (Pa) at 25 ° C. after curing of the adhesive layer of Example 1 were also measured.

[Storage modulus (Pa)]
For the storage elastic modulus of the adhesive layer, an adhesive film having a thickness of 100 μm was prepared for the sample composed of the adhesive layer, and a viscoelasticity measuring device (RSA-G2 manufactured by TA Instruments) was used, the measurement frequency was 1 Hz, and the temperature rise rate. The measurement was carried out according to JIS K7244 under the condition of 5 ° C./min. The measurement sample was coated with a roll of a resin varnish on a release film, and then the film with a coating film was allowed to stand in an oven. It was dried at 110 ° C. for 4 minutes to form a B-stage adhesive layer (thickness 50 μm). Next, the adhesive layers were heat-laminated at 120 ° C. so that the adhesive surfaces were in contact with each other to form a pre-curing adhesive. A film (thickness 100 μm) was formed. This pre-curing adhesive film (thickness 100 μm) was allowed to stand in an oven and heat-cured at 150 ° C. for 60 minutes to perform a post-curing adhesive film (100 mm ×). 100 mm) was prepared. The release film was peeled off from the adhesive film, and the storage elastic modulus (Pa) of the adhesive layer was measured.

The relative permittivity and dielectric loss tangent of the adhesive layer in the laminate of Example 1 at a frequency of 28 GHz were also measured.

[Relative permittivity and dielectric loss tangent]
For the relative permittivity and dielectric loss tangent of the adhesive layer, a network analyzer MS46122B (manufactured by Anritsu) and an open resonator Fabry Perot DPS-03 (manufactured by KEYCOM) are used, and the temperature is 23 ° C. by the open resonator method. , The measurement was carried out under the condition of a frequency of 28 GHz. For the measurement sample, a resin varnish was rolled on the release film, and then the film with the coating film was allowed to stand in an oven and dried at 110 ° C. for 4 minutes to form a B-stage adhesive layer. (Thickness 50 μm) was formed. Next, the adhesive layers were heat-laminated at 120 ° C. so that the adhesive surfaces were in contact with each other to form a pre-curing adhesive film (thickness 100 μm). This pre-curing adhesive film (thickness 100 μm) was allowed to stand in an oven and heat-cured at 150 ° C. for 60 minutes to prepare a post-curing adhesive film (100 mm × 100 mm). After curing, the release film was peeled off from the adhesive film, and the relative permittivity and dielectric loss tangent of the adhesive layer were measured.

Table 1 shows the results of each measurement.

(Examples 2 to 5)
In Example 1, the laminates of Examples 2 to 5 were produced in the same manner as in Example 1 except that the types and blending amounts of the components constituting the adhesive layer were changed as shown in Table 1. ..
The produced laminate was evaluated in the same manner as in Example 1.
The results are shown in Table 1.

(Comparative Example 1 to Comparative Example 4)
In Example 1, the laminates of Comparative Examples 1 to 4 were produced in the same manner as in Example 1 except that the types and blending amounts of the components constituting the adhesive layer were changed as shown in Table 1. ..
The produced laminate was evaluated in the same manner as in Example 1.
The results are shown in Table 1.

As shown in Examples 1 to 5, the adhesive layer made of the adhesive composition of the present invention has excellent adhesion (adhesiveness) after heat curing and also has adhesiveness (adhesiveness) in the laminating step. Is also excellent.

This application claims priority based on Japanese Patent Application No. 2019-230039, which is a Japanese patent application filed on December 20, 2019, and incorporates all the contents of the Japanese patent application.

The laminate having an adhesive layer made of the adhesive composition of the present invention is suitable for manufacturing FPC-related products for electronic devices such as smartphones, mobile phones, optical modules, digital cameras, game machines, notebook computers, and medical devices. Can be used for.

Claims

An adhesive composition containing a styrene-based elastomer containing a carboxy group, a styrene-based elastomer not containing a carboxy group, and an epoxy resin.
The adhesive composition according to claim 1, wherein the content of the epoxy resin is 1 to 20 parts by mass with respect to 100 parts by mass of the adhesive composition.
The adhesive composition according to claim 1 or 2, wherein the content of the styrene-based elastomer containing the carboxy group is less than 50 parts by mass with respect to 100 parts by mass of the adhesive composition.
The adhesive composition according to any one of claims 1 to 3, wherein the epoxy resin has a softening point or a melting point of 90 ° C. or lower.
The adhesive composition according to any one of claims 1 to 4, further containing an organic peroxide.
An adhesive layer comprising the adhesive composition according to any one of claims 1 to 5, wherein the storage elastic modulus of the adhesive layer at 120 ° C. before curing is 5 × 10 5 Pa or less. , Adhesive layer.
An adhesive layer made of the adhesive composition according to any one of claims 1 to 5, a storage modulus at 25 ° C. after curing of the adhesive layer, is 8 × 10 7 Pa or higher , Adhesive layer.
The relative permittivity of the adhesive layer measured at a frequency of 28 GHz with respect to the adhesive layer obtained by curing the adhesive composition according to any one of claims 1 to 5 is 3.5 or less, and An adhesive layer having a dielectric loss tangent of 0.01 or less.
Base film and
A laminate having an adhesive layer composed of the adhesive composition according to any one of claims 1 to 5, or an adhesive layer according to any one of claims 6 to 8.
The laminate according to claim 9, wherein the base film contains a polyetheretherketone (PEEK) resin.
A coverlay film with an adhesive layer containing the laminate according to claim 9 or 10.
A copper-clad laminate containing the laminate according to claim 9 or 10.
A printed wiring board including the laminate according to claim 9 or 10.
A shield film containing the laminate according to claim 9 or 10.
A printed wiring board with a shield film containing the laminate according to claim 9 or 10.