WO2022163284A1

WO2022163284A1 - Adhesive composition

Info

Publication number: WO2022163284A1
Application number: PCT/JP2021/048602
Authority: WO
Inventors: 航片桐; 栞門間
Original assignee: 信越ポリマー株式会社
Priority date: 2021-01-29
Filing date: 2021-12-27
Publication date: 2022-08-04
Also published as: JPWO2022163284A1

Abstract

Provided is an adhesive composition for forming low-dielectric adhesive layers which have satisfactory electrical properties (dielectric properties) that render the adhesive layer adaptable to the 5th generation mobile communication system (5G) and which have satisfactory adhesiveness also to low-dielectric base films having poor bondability and further have heat resistance and chemical resistance (solvent resistance), the adhesive composition being capable of being reduced in resin flow.　The adhesive composition comprises a hardener and a resin composition including a modified styrene-based elastomer, wherein the modified styrene-based elastomer is contained in an amount of 25 parts by mass or more per 100 parts by mass of the resin composition and the resin composition has a melt flow rate (200°C, 21.60 kg) of 40 g/10 min or less.

Description

adhesive composition

The present invention relates to adhesive compositions. More particularly, it relates to an adhesive composition that can be used for bonding electronic parts and the like.

With the miniaturization and weight reduction of electronic devices, the applications for bonding electronic parts and the like are diversifying, and the demand for laminates with adhesive layers is increasing.
In addition, flexible printed circuit boards (hereinafter also referred to as FPCs), which are one type of electronic component, need to process a large amount of data at high speed, and are becoming increasingly compatible with high frequencies. In order to increase the frequency of the FPC, it is necessary to reduce the dielectric of the constituent elements, and low dielectric base films and low dielectric adhesives are being developed. In particular, in order to efficiently transmit signals having frequencies in the 6 GHz and 28 GHz bands used in the 5th generation mobile communication system (hereinafter also referred to as 5G), a base film with low loss even in the 28 GHz millimeter wave band, Adhesives are becoming more and more important.

However, low-dielectric adhesives have a low polarity of the base molecule, so it is difficult to develop adhesion (adhesiveness) with the base film and other components related to electronic parts. In some cases, adhesion (adhesiveness) to adhesives is poor, and there is a demand for improved adhesion.
Therefore, in order to meet high adhesiveness while having good electrical properties (low dielectric constant and low dielectric loss tangent), an adhesive containing a carboxy group-containing styrene elastomer (A) and an epoxy resin (B) Using an adhesive composition, a laminate comprising an adhesive layer made of the adhesive composition and a base film has been proposed (see, for example, Patent Document 1).

WO2016/017473

Low-dielectric adhesives also have the problem of easy resin flow due to the low polarity of the base material molecules.
However, from the viewpoint of obtaining an adhesive composition that prevents resin flow, Patent Document 1 is not satisfactory and has room for improvement.

Therefore, the present invention has good electrical properties (dielectric properties) that are compatible with 5G, exhibits good adhesion even to low-dielectric base films with poor adhesion, and has heat resistance and chemical resistance. It is an object of the present invention to provide an adhesive composition for forming a low-dielectric adhesive layer that also has solvent properties, and that is capable of suppressing resin flow.

The present inventors have made intensive studies to solve the above problems, and have found that an adhesive composition containing a modified styrene-based elastomer is used as a resin composition that is the main ingredient of the adhesive composition. By adjusting the melt flow rate (MFR) of the composition (resin composition) other than the curing agent of the product to a desired value, an adhesive composition containing a resin composition exhibiting the predetermined MFR is provided. can be solved, and the present invention has been completed.

The present invention includes the following aspects.
[1] Containing a resin composition containing a modified styrene-based elastomer and a curing agent,
The content of the modified styrene-based elastomer relative to 100 parts by mass of the resin composition is 25 parts by mass or more,
The adhesive composition, wherein the resin composition has a melt flow rate (200° C., load 21.60 kg) of 40 g/10 minutes or less.
[2] The adhesive composition according to [1], wherein the resin composition has a melt flow rate (200°C, load: 21.60 kg) of 0.1 g/10 minutes or more.
[3] The adhesive composition according to [1] or [2], wherein the content of the curing agent is 25 parts by mass or less 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 modified styrene elastomer is a styrene elastomer containing a carboxy group.
[5] The adhesive composition according to any one of [1] to [3], wherein the modified styrene elastomer is an amino group-containing styrene elastomer.
[6] The adhesive composition according to any one of [1] to [5], wherein the resin composition contains at least two styrene elastomers.
[7] The adhesive composition according to any one of [1] to [6], wherein the curing agent contains an epoxy resin.
[8] The adhesive composition according to [7], wherein the curing agent contains an epoxy-modified styrene-butadiene copolymer.
[9] The adhesive composition according to any one of [1] to [8], wherein the resin composition contains a styrene-based elastomer having a weight average molecular weight (Mw) of 100,000 to 500,000.
[10] The adhesive composition according to any one of [1] to [9], wherein the resin composition contains a filler.
[11] The adhesive composition according to any one of [1] to [10], wherein the curing agent contains an organic peroxide.
[12] relative to the adhesive layer obtained by curing the adhesive composition according to any one of [1] to [11], the dielectric constant of the adhesive layer measured at a frequency of 28 GHz is 3 or less; and an adhesive layer having a dielectric loss tangent of 0.005 or less.
[13] a base film;
A laminate having an adhesive layer made of the adhesive composition according to any one of [1] to [11] or the adhesive layer according to [12].
[14] The laminate according to [13], wherein the base film contains a polyetheretherketone (PEEK) resin.
[15] A coverlay film with an adhesive layer comprising the laminate according to [13] or [14].
[16] A copper-clad laminate comprising the laminate according to [13] or [14].
[17] A printed wiring board comprising the laminate according to [13] or [14].
[18] A shielding film comprising the laminate according to [13] or [14].
[19] A printed wiring board with a shielding film comprising the laminate according to [13] or [14].

According to the present invention, while having good electrical properties (dielectric properties) compatible with 5G, it exhibits good adhesion even to low-dielectric substrate films with poor adhesion, and has heat resistance and chemical resistance (resistance). It is possible to provide an adhesive composition for forming a low-dielectric adhesive layer that also has solvent properties and that can also suppress resin flow.

Hereinafter, the adhesive composition of the present invention, a laminate containing an adhesive layer made of the adhesive composition, and an electronic component-related constituent member containing the laminate will be described in detail. is an example as one embodiment of the present invention, and is not limited to these contents.

(Adhesive composition)
The adhesive composition of the present invention contains a resin composition containing a modified styrene-based elastomer and a curing agent.
The content of the modified styrene-based elastomer with respect to 100 parts by mass of the resin composition is 25 parts by mass or more.
The melt flow rate (200° C., load 21.60 kg) of the resin composition is 40 g/10 minutes or less.

The adhesive composition of the present invention may contain other components as necessary.
The adhesive composition of the present invention exhibits good adhesion even when it is a low dielectric adhesive composition, is excellent in heat resistance and chemical (solvent resistance) resistance, and can also suppress resin flow. It becomes a composition.

<Resin composition>
The resin composition of the adhesive composition contains a styrene-based elastomer.
In addition to the styrene-based elastomer, the resin composition may contain resin components other than the styrene-based elastomer and other components.

<<Styrene Elastomer>>
Styrenic elastomers are copolymers composed mainly of block and random structures of unsaturated hydrocarbons and aromatic vinyl compounds, and hydrogenated products thereof.
There are few highly polar bonding groups in the molecule, and good electrical properties (dielectric properties) can be imparted to the composition. Another advantage is that the molecular weight can be easily controlled and the properties of the adhesive composition can be stably produced compared to other types of elastomers.
Examples of aromatic vinyl compounds include styrene, t-butylstyrene, α-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-diethyl-p-aminoethylstyrene and vinyltoluene. Examples of unsaturated hydrocarbons include ethylene, propylene, butadiene, isoprene, isobutene, 1,3-pentadiene and 2,3-dimethyl-1,3-butadiene.
Specific examples of styrene-based elastomers include styrene-butadiene block copolymers, styrene-ethylenepropylene block copolymers, styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, and styrene-ethylenebutylene. -styrene block copolymers and styrene-ethylene propylene-styrene block copolymers.
Among the above copolymers, styrene-ethylene is preferred because it can impart adhesiveness and electrical properties (dielectric properties) to the adhesive composition, and the control of the molecular structure is relatively simple, making it easy to adjust the properties of the adhesive composition. Butylene-styrene block copolymers and styrene-ethylene propylene-styrene block copolymers are preferred. Further, 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 60/40. preferably 30/70 to 60/40. If the mass ratio is 10/90 to 60/40, the adhesive composition can have excellent adhesive properties. If the mass ratio is from 30/70 to 60/40, interaction with the skeleton derived from the aromatic vinyl compound is increased, and compatibility with other resins is improved. In addition, resin flow can be suppressed by increasing the cohesive force.

As for the weight average molecular weight (Mw) of the styrene-based elastomer, Mn is preferably 100,000 to 500,000. If the weight average molecular weight is at least the above lower limit, excellent adhesiveness can be exhibited. In addition, by increasing the frequency of entanglement between molecules, it is possible to control the fluidity of the resin and suppress the resin flow. When the weight-average molecular weight is equal to or less than the above upper limit, the viscosity does not become too high when dissolved in a solvent, making coating easier. In addition, compatibility with other resins such as curing agents is improved.
The weight average molecular weight is a value obtained by converting the molecular weight measured by gel permeation chromatography (hereinafter also referred to as "GPC") into polystyrene.
The resin composition according to the present invention may contain two or more styrene elastomers.
For example, by using a modified styrene elastomer that has good surface adhesion to the adherend and a non-modified styrene elastomer that can adjust the elastic modulus for each temperature of the adhesive composition, high adhesion and Liquidity control becomes possible.
In particular, modified styrene-based elastomers and unmodified unmodified styrene-based elastomers have similar molecular structures, and thus have good compatibility.

<<<Modified Styrene Elastomer>>>
The resin composition, which is the main ingredient of the adhesive composition, contains a modified styrene-based elastomer.
Modified styrene-based elastomers are copolymers mainly composed of block and random structures of unsaturated hydrocarbons and aromatic vinyl compounds, and hydrogenated products thereof containing carboxy groups, amino groups, epoxy groups, isocyanate groups, acryloyl , a hydroxyl group, a mercapto group, an imide group, an alkoxysilyl group, and the like.
The content of the modified styrene-based elastomer is 25 parts by mass or more with respect to 100 parts by mass of the resin composition. When the content of the modified styrene-based elastomer is 25 parts by mass or more, adhesion due to the interaction of the substituents can be exhibited, and heat resistance and the like can be exhibited by sufficiently increasing the crosslink density.
Examples of modified styrene-based elastomers include styrene-based elastomers containing carboxy groups and styrene-based elastomers containing amino groups described below.

<<<<Carboxy Group-Containing Styrene Elastomer>>>>
A styrene-based elastomer containing a carboxyl group has high adhesion, can impart flexibility to a cured product, and is effective as a component that imparts good electrical properties.
By containing a styrene-based elastomer containing a carboxyl group in the adhesive composition, the adhesive composition is flexible even for adherends such as base films and metal foils with good electrical properties and low polarity. Since the substance can sufficiently follow the surface of the adherend, the highly polar carboxyl group can exhibit adhesion, thereby improving the adhesion of the adhesive layer. In addition, since the styrene-based elastomer containing a carboxyl group is reactive, the heat resistance and chemical resistance of the adhesive layer are improved by reacting it with a curing agent.
Moreover, the dispersibility of the filler in the dispersion is improved by containing the carboxyl group.
Styrenic elastomers containing carboxyl groups are copolymers mainly composed of block and random structures of unsaturated hydrocarbons and aromatic vinyl compounds, and hydrogenated products thereof modified with unsaturated carboxylic acids. be.
Types of the aromatic vinyl compound and unsaturated hydrocarbon and specific examples of the styrene-based elastomer are as described in the section <<Styrene-based elastomer>> above.

Modification of a styrene-based elastomer containing a carboxy group can be carried out, for example, by copolymerizing an unsaturated carboxylic acid during 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 carboxy groups is preferably 0.1 to 25 mgKOH/g, more preferably 0.5 to 23 mgKOH/g. When the 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 30 mgKOH/g or less, the cohesive force of the adhesive composition is suppressed, resulting in excellent adhesiveness and excellent electrical properties.

<<<<Styrene Elastomer Containing Amino Group>>>>
By containing a styrene-based elastomer containing an amino group in the adhesive composition, the amino group expresses a strong interaction with the low-dielectric substrate film, and the reactivity of the adhesive composition increases. Adhesion of the adhesive layer is improved. In addition, since the amino group-containing styrene-based elastomer is reactive, the heat resistance and chemical resistance of the adhesive layer are improved by reacting it with the curing agent.
Since it contains an amino group, adhesion to metals is improved.
Styrenic elastomers containing amino groups are copolymers mainly composed of block and random structures of unsaturated hydrocarbons and aromatic vinyl compounds, and hydrogenated products thereof modified with amines.
Types of the aromatic vinyl compound and unsaturated hydrocarbon and specific examples of the styrene-based elastomer are as described in the section <<Styrene-based elastomer>> above.

The method of amine-modifying the styrene elastomer is not particularly limited, and a known method can be used. A modification method, a method of amine-modifying a (hydrogenated) copolymer by using an unsaturated monomer having an amino group as a raw material to be copolymerized, and a styrene-based elastomer containing a carboxy group with two amino groups. A method of modifying the amine by reacting the above amine modifier to form an amide structure or an imide structure, and the like.

From the viewpoint of securing good electrical properties (low dielectric constant, low dielectric loss) and adhesion (adhesiveness) of the adhesive composition, the total nitrogen content in the amino group-containing styrene elastomer is , preferably 50 to 5000 ppm, more preferably 200 to 3000 ppm. If the total nitrogen content is at least the above lower limit, excellent adhesion can be exhibited. If the total nitrogen content is equal to or less than the above upper limit, the electrical properties are excellent.
The total nitrogen content in the styrene-based elastomer containing amino groups can be determined according to JIS-K2609 using a trace nitrogen analyzer ND-100 (manufactured by Mitsubishi Chemical Corporation).

Only one type of modified styrene-based elastomer may be used, or two or more types may be contained.

<<Other resin components and other components>>
The resin component according to the present invention may contain resin components other than the styrene elastomer and other components in addition to the styrene elastomer.

<<<Resin components other than styrene-based elastomer>>>
The resin composition according to the present invention can contain, for example, thermoplastic resins other than the styrene-based elastomer to such an extent that the functions of the adhesive composition are not affected.
Examples of other thermoplastic resins include phenoxy resins, polyamide resins, polyimide resins, bismaleimide resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, polyacetal resins, polyethylene resins, polypropylene resins, and polybutadiene resins. Resins, polyvinyl-based resins, fluorine-based resins, and the like can be mentioned. These thermoplastic resins may be used alone or in combination of two or more.
The compatibility of the styrene-based elastomer with the other thermoplastic resins mentioned above may change the resin flow and MFR values described later, and it is also possible to adjust them by the compounding method.

<<<Other Ingredients>>>
The resin composition according to the present invention can contain, for example, components other than the styrene-based elastomer.
Other components include, for example, fillers, fibers, tackifiers, flame retardants, heat antioxidants, leveling agents, defoaming agents, inorganic fillers and pigments, to the extent that they do not affect the function of the adhesive composition. can be contained in
Depending on the dispersibility of the styrene-based elastomer and other components, the resin flow and the MFR value described later may change, and it is also possible to adjust it by blending and dispersing method.

<<<<filler>>>>
The adhesive composition of the present invention preferably contains a filler.
As the filler according to the present invention, for example, an inorganic filler is preferable from the viewpoint of heat resistance and mechanical property control of the adhesive composition, and as the inorganic filler, a silicon-based inorganic filler and boron nitride are preferable from the viewpoint of electrical properties. preferable. Moreover, as the silicon-based inorganic filler, for example, mica and talc are preferable because they can control the mechanical properties of the adhesive composition even in a small amount and have excellent electrical properties.
Further, as the filler according to the present invention, for example, an organic filler is preferable from the viewpoint of dispersibility and brittleness, and as the organic filler, a styrene-based spherical filler is preferable from the viewpoint of electrical properties, and a styrene-based hollow filler is preferable. more preferred.
Further, as the filler according to the present invention, for example, engineering plastic resin filler is preferable from the viewpoint of dielectric properties, and as the engineering plastic resin filler, from the viewpoint of chemical resistance, fluororesin powder, liquid crystal polymer powder, syndiotactic polystyrene powder. is preferred.
These may be used alone or in combination of two or more.
The content of the filler contained in the adhesive composition of the present invention is preferably 0.5 to 25 parts by volume with respect to 100 parts by volume of the resin composition, and 1 to 15 parts by volume with respect to 100 parts by volume of the resin composition. is more preferable.
The shape of the filler is not particularly limited and can be appropriately selected depending on the purpose. For example, the inorganic filler may be a spherical inorganic filler or a non-spherical inorganic filler, but a non-spherical inorganic filler is preferable from the viewpoint of coefficient of thermal expansion (CTE) and film strength. The shape of the non-spherical inorganic filler may be any three-dimensional shape other than a spherical shape (substantially spherical shape), and examples thereof include plate-like, scale-like, columnar, chain-like, and fibrous shapes. Among them, from the viewpoint of coefficient of thermal expansion (CTE) and film strength, plate-like and scale-like inorganic fillers are preferable, and plate-like inorganic fillers are more preferable.

Examples of the fibers include carbon fiber, glass fiber, aramid fiber, cellulose fiber, and the like. These fibers may be used alone or in combination of two or more.

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

The above flame retardant may be either an organic flame retardant or an inorganic flame retardant. Examples of organic flame retardants include melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, amide ammonium phosphate, amide ammonium polyphosphate, carbamate phosphate, and carbamate polyphosphate. , aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, titanium tetrakisdiethylphosphinate , titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate, and titanium tetrakisdiphenylphosphinate; triazine compounds such as melamine, melam, and melamine cyanurate; , isocyanuric acid compounds, triazole compounds, tetrazole compounds, diazo compounds, urea, and other nitrogen-based flame retardants; silicone compounds, silane compounds, and other silicon-based flame retardants. Inorganic flame retardants include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, and calcium hydroxide; tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, Metal oxides such as molybdenum oxide and nickel oxide; zinc carbonate, magnesium carbonate, barium carbonate, zinc borate, hydrated glass and the like. These flame retardants can be used in combination of two or more.

Examples of the heat antiaging agent include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propione. -tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, pentaerythritoltetrakis[3-(3,5-di-t-butyl-4- Phenolic 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; and phosphorus-based antioxidants such as trisnonylphenyl phosphite and tris(2,4-di-tert-butylphenyl)phosphite. 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, copper, silver, and the like. These may be used alone or in combination of two or more.

<<Characteristics of Resin Composition>>
The melt flow rate (MFR) of the resin composition is 40 g/10 minutes or less under measurement conditions of 200° C. and a load of 21.60 kg.
Here, the MFR is a numerical value representing the fluidity of the resin composition, and the larger the numerical value, the higher the fluidity.
The MFR is measured using an extrusion type plastometer defined by JIS K6760, and the measuring method conforms to the method defined by JIS K7210 (1976). In the present invention, the measurement is performed under the conditions of 200° C. and a load of 21.6 kg.
The temperature conditions for MFR measurement are based on the fact that the thermocompression bonding temperature that is generally set when mounting the adhesive layer is 150 to 200°C, and that the higher the temperature, the more likely resin flow occurs. and measured at 200°C. The load condition is measured at a standard load of 21.60 kg, which is close to the thermocompression pressure of 2 to 3 MPa generally set when mounting the adhesive layer.
The MFR of the resin composition is preferably 40 g/10 minutes or less, more preferably 10 g/10 minutes or less, and further preferably 5 g/10 minutes or less under measurement conditions of 200° C. and a load of 21.60 kg. More preferably, it is 3 g/10 minutes or less. Moreover, the MFR is more preferably 0.1 g/10 minutes or more. When the MFR is 40 g/10 minutes or less, resin flow can be suppressed. When the MFR is 10 g/10 minutes or less, the resin flow can be suppressed even if the amount of the curing agent is increased, and heat resistance and the like can be improved by further increasing the crosslink density. When the MFR is equal to or less than the above upper limit, the resin flow can be made smaller. When the MFR is 0.1 g/10 minutes or more, it is possible to follow a step such as a pattern of a printed wiring board.

<Curing agent>
The curing agent reacts with the resin composition to increase the crosslink density of the resin composition, thereby exhibiting high adhesion to adherends and heat resistance of the cured adhesive. The curing agent is composed of a cross-linking agent that reacts with the resin composition to form a cross-linked structure, and may optionally contain a reaction accelerator that accelerates the reaction between the resin composition and the cross-linking agent.
From the viewpoint that the content of the curing agent is within a suitable range for expressing the effect of the MFR of the resin composition and for expressing the performance of the adhesive, the adhesive composition is the sum of the resin composition and the curing agent. It is preferably 25 parts by mass or less per 100 parts by mass of the substance.
The content of the curing agent is more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less. If the content of the curing agent is equal to or less than the above upper limit, the resin flow can be controlled to be even smaller, and adhesion and dielectric properties are improved. Moreover, from the viewpoint of sufficiently cross-linking and exhibiting adhesiveness, heat resistance, etc., the content of the curing agent is more preferably 0.05 parts by mass or more.

<<crosslinking agent>>
Examples of cross-linking agents include epoxy resins, isocyanate resins, phenol resins, cyanate resins, polyamides, polyurethanes, organic peroxides, silane coupling agents, benzoxazines, allyl compounds, propenyl compounds, and the like. The cross-linking agent can be appropriately selected depending on the purpose, but from the viewpoint of being able to cure the adhesive composition at an appropriate curing temperature and exhibiting heat resistance, it is preferably an epoxy resin. From the viewpoint of improving the cross-linking density of the adhesive composition without containing a highly polar functional group and improving the adhesiveness (adhesiveness), heat resistance and chemical resistance of the adhesive layer, organic peroxide preferably an object. Only one type of cross-linking agent may be used, or two or more types may be contained.

<<<epoxy resin>>>
The epoxy resin reacts with the carboxy group in the styrene elastomer containing the carboxy group and the amino group in the styrene elastomer containing the amino group, resulting in high adhesion to the adherend and heat resistance of the cured adhesive. It is a component that expresses sexuality.

Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, or hydrogenated versions thereof; diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, p-hydroxybenzoic acid Glycidyl ester epoxy resins such as glycidyl ester, diglycidyl tetrahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, and triglycidyl trimellitate; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenylglycidyl ether ethane, triphenylglycidyl ether ethane, sorbitol glycidyl ether-based epoxy resins such as polyglycidyl ether of polyglycerol, polyglycidyl ether of polyglycerol; glycidylamine-based epoxy resins such as triglycidyl isocyanurate and tetraglycidyldiaminodiphenylmethane; Examples include, but are not limited to, epoxy resins and the like. Novolac epoxy resins such as xylene structure-containing novolac epoxy resins, naphthol novolac epoxy resins, phenol novolac epoxy resins, o-cresol novolac epoxy resins, and bisphenol A novolak epoxy resins can also be used.
These epoxy resins may be used alone or in combination of two or more.

Specific examples of novolak-type epoxy resins include Mitsubishi Chemical Corporation's "YX7700" (xylene structure-containing novolak-type epoxy resin), Nippon Kayaku Co., Ltd.'s "NC7000L" (naphthol novolac-type epoxy resin), "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemical & Materials Co., Ltd., "N-690" (cresol novolak type epoxy resin) manufactured by DIC Corporation, "N-695" manufactured by DIC Corporation ( cresol novolak type epoxy resin) and the like.

The epoxy resin is more preferably an epoxy-modified resin. This is because it has good compatibility with a main agent (resin composition) containing a styrene-based elastomer, and can exhibit an effect of suppressing resin flow without impairing the effect of adjusting the MFR of the main agent.

<<<<epoxy-modified resin>>>>
As the epoxy-modified resin, for example, an epoxy-modified resin having a structure represented by the following formula (1) is preferable.

(At least one of R ¹ and R ² is a substituent other than H, and at least one of R ³ and R ⁴ is a substituent other than H.)
Epoxy-modified resins having a structure represented by the above formula (1) have an epoxy structure and a carboxy group in a styrene-based elastomer containing the above carboxy group and styrene containing the above amino group, compared with ordinary epoxy resins. It reacts with amino groups in the system elastomer or self-polymerizes at a high reaction rate, and is effective as a component that exhibits high adhesiveness to adherends and heat resistance of cured adhesives.

A preferred embodiment of the epoxy-modified resin is an epoxy-modified resin having a structure represented by the following formula (2).

(R ⁵ and R ⁶ each independently represent hydrogen or an alkyl group having 10 or less carbon atoms. When a plurality of structures represented by the above formula (2) are present in the epoxy-modified resin, each formula Each R ⁵ in (2) may be the same or different, each R ⁶ in formula (2) may be the same or different, and * represents a bonding group. )
In the above formula (2), both R ⁵ and R ⁶ are more preferably hydrogen from the viewpoint of reducing steric hindrance near the epoxy group and allowing the reaction to proceed sufficiently.

The epoxy-modified resin preferably contains an unsaturated bond other than an aromatic ring such as an olefin skeleton or a vinyl group. Unsaturated bonds other than aromatic rings such as olefin skeletons and vinyl groups can be incorporated into reactions involving epoxy groups to accelerate the reaction rate and increase the crosslink density. As a result, heat resistance and chemical resistance can be improved even with a small amount. In addition, by cross-linking unsaturated bonds other than aromatic rings by radical polymerization, the cross-linking density of the epoxy-modified resin can be increased, and heat resistance and chemical resistance can be improved.

A preferred embodiment of the epoxy-modified resin is an epoxy-modified resin having a structure represented by the following formula (3).

(R ⁷ and R ⁸ each independently represent hydrogen or an alkyl group having 10 or less carbon atoms. When a plurality of structures represented by the above formula (3) are present in the epoxy-modified resin, each formula R ⁷ in (3) may be the same or different, and R ⁸ in each formula (3) may be the same or different, * represents a bonding group. )
In formula (3) above, both R ⁷ and R ⁸ are more preferably hydrogen.

The epoxy-modified resin is preferably an epoxy-modified resin having a structure represented by the above formula (1) and a structure represented by the above formula (3), and the structure represented by the above formula (2) and the above formula It is more preferable that it is an epoxy-modified resin having the structure represented by (3).

A preferred embodiment of the epoxy-modified resin includes an epoxy-modified resin having at least one of the structure represented by the following formula (4) and the structure represented by the following formula (5). It is also preferable to have both a structure represented by the following formula (4) and a structure represented by the following formula (5).

(R ⁹ and R ¹⁰ each independently represent hydrogen or an alkyl group having 10 or less carbon atoms. When there are multiple structures represented by the above formula (4) in the epoxy-modified resin, each formula Each R ⁹ in (4) may be the same or different, each R ¹⁰ in formula (4) may be the same or different, and * represents a bonding group. )
In formula (4) above, both R ⁹ and R ¹⁰ are more preferably hydrogen.

(R ¹¹ and R ¹² each independently represent hydrogen or an alkyl group having 10 or less carbon atoms. When a plurality of structures represented by the above formula (5) are present in the epoxy-modified resin, each formula R ¹¹ in (5) may be the same or different, R ¹² in each formula (5) may be the same or different, and * represents a bonding group. )
In formula (5) above, both R ¹¹ and R ¹² are more preferably hydrogen.

An epoxy-modified resin in which the epoxy-modified resin has a structure represented by the above formula (1) and at least one of a structure represented by the above formula (4) and a structure represented by the above formula (5). It is preferably a resin, and an epoxy having a structure represented by the above formula (2) and at least one of the structure represented by the above formula (4) and the structure represented by the above formula (5) Modified resin and more preferred.
Further, a structure represented by the above formula (1) or the above formula (2), a structure represented by the above formula (3), a structure represented by the above formula (4), and a structure represented by the above formula (5) Epoxy-modified resins having at least one of the structures represented are also preferred.

Moreover, the epoxy-modified resin is preferably an epoxy-modified organic compound obtained by modifying an organic compound containing an unsaturated bond. By modifying an organic compound containing an unsaturated bond, the structure represented by the above formula (1) and the unsaturated bond can coexist in the molecule depending on the modification rate, and the reaction of the epoxy structure can be performed with an olefin skeleton or It is easy to impart the effect of an unsaturated bond to a ring other than an aromatic ring such as a vinyl group.
Here, as a method for modifying an organic compound containing an unsaturated bond into an epoxy-modified organic compound, a reaction in which an epoxy skeleton is formed with a peroxide is effective. Peroxides used include percarboxylic acid compounds such as performic acid, peracetic acid and perpropionic acid.
The epoxy-modified resin is preferably an epoxy-modified elastomer obtained by modifying an elastomer containing unsaturated bonds. Epoxy-modified elastomer can give flexibility to the cured product, and by suppressing the deterioration of the toughness of the cured product due to epoxy curing, it is possible to maintain adhesion when the laminate is bent, and improve heat resistance and chemical resistance. do not lower.

Furthermore, the epoxy-modified resin is preferably a styrene-based elastomer.
The epoxy-modified resin having the structure represented by the formula (1) or the formula (2) preferably has a structural unit of styrene in addition to the structures represented by the formulas (3) to (5). .
Together with the styrene-based elastomer contained in the adhesive resin composition of the present invention, the epoxy-modified resin is also a styrene-based elastomer, so that when mixing the two, the compatibility is improved, and the styrene-based elastomer containing the carboxy group is improved. This is because the reaction with the carboxyl group in the polymer or the amino group in the styrene-based elastomer containing the amino group can proceed efficiently.

Epoxy-modified resins include alicyclic epoxy compounds having an alicyclic epoxy group such as epoxycyclohexane, epoxidized polybutadiene, epoxy compounds of styrene-butadiene block copolymers, and the like.
Among them, an epoxy compound of a styrene-butadiene block copolymer is more preferable. Since the styrene-butadiene block copolymer contains an unsaturated bond, the structure represented by the above formula (1) and the unsaturated bond can coexist in the molecule. It is easy to impart the effect of unsaturated bonds to groups other than aromatic rings.
As the epoxy-modified resin, commercially available epoxy compounds can also be used. Friend AT501 and Epo Friend CT310 (manufactured by Daicel) can be mentioned.

The weight average molecular weight (Mw) of the epoxy-modified resin is preferably 30,000 or more, more preferably 50,000 or more. When the weight-average molecular weight is 30,000 or more, the softening of the adhesive composition can be suppressed, and the resin can be prevented from flowing during thermocompression bonding. When the weight average molecular weight is 50,000 or more, the flexibility of the epoxy-modified resin is improved, and the toughness of the cured product is improved. Also, the weight average molecular weight (Mw) of the epoxy-modified resin is preferably 200,000 or less, more preferably 160,000 or less. If the weight average molecular weight is 200,000 or less, the compatibility with the styrene elastomer is further improved. If the weight-average molecular weight is 160,000 or less, the elastic modulus of the adhesive composition can be lowered and the shape of the adherend can be followed.

<<<organic peroxide>>>
The curing agent of the present invention preferably contains an organic peroxide. By containing an organic peroxide, the cross-linking density of the adhesive composition is improved without containing a highly polar functional group, and the adhesion (adhesiveness), heat resistance and chemical resistance of the adhesive layer are improved. can be improved.
Unsaturated bonds and acryloyl groups contained in resin compositions, and unsaturated bonds other than aromatic rings such as olefin skeletons and vinyl groups contained in the above-mentioned epoxy-modified resins can be radically polymerized by radicals generated from organic peroxides. The resin component can be crosslinked, and the adhesion (adhesiveness), heat resistance, and chemical resistance of the adhesive layer can be further improved.
In addition, since radicals generated from organic peroxides have high hydrogen abstraction ability and can crosslink hydrogenated styrene elastomers, the crosslink density of the adhesive composition is further improved without containing highly polar functional groups. can do.

Examples of organic peroxides include benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, t-butylperoxyethylhexanoate, 1,1'-bis-(t-butylperoxy)cyclohexane, t-amyl Organic peroxides such as peroxy-2-ethylhexanoate and t-hexylperoxy-2-ethylhexanoate are included.

Examples of the coupling agent include vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, N -2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanate-topropyltri Examples include silane coupling agents such as ethoxysilane and imidazole silane; titanate coupling agents; aluminate coupling agents; and zirconium coupling agents. These may be used alone or in combination of two or more.

Examples of the benzoxazines include 6,6-(1-methylethylidene)bis(3,4-dihydro-3-phenyl-2H-1,3-benzoxazine), 6,6-(1-methylethylidene)bis( 3,4-dihydro-3-methyl-2H-1,3-benzoxazine) and the like, and two or more of them may be combined. A phenyl group, a methyl group, a cyclohexyl group, or the like may be bonded to the nitrogen of the oxazine ring. Further, specific examples of benzoxazine resins include "Benzoxazine Fa", "Benzoxazine Pd" and "Benzoxazine ALP-d" manufactured by Shikoku Kasei Co., Ltd., Tohoku Kako Co., Ltd. ``CR-276'' and ``BZ-LB-MDA'' manufactured by K.K. These may be used alone or in combination of two or more.

Specific examples of the above allyl compounds include "RESITOP SBA02A", "RESITOP APG-LC", "RESITOP LVA01", "RESITOP FATC809" and "RESITOP FTC809AE" manufactured by Gun Ei Chemical Industry Co., Ltd. These may be used alone or in combination of two or more.

Specific examples of the propenyl compound include "Resitop BPN01S" manufactured by Gun Ei Chemical Industry Co., Ltd., and the like. These may be used alone or in combination of two or more.

<<Reaction Accelerator>>
The reaction accelerator is used, for example, for the purpose of promoting the reaction between the styrene-based elastomer, particularly the modified styrene-based elastomer, and the cross-linking agent. As the reaction accelerator, for example, a tertiary amine-based reaction accelerator, a tertiary amine salt-based reaction accelerator, an imidazole-based reaction accelerator, and the like can be used.

Tertiary amine reaction accelerators 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.

Tertiary amine salt-based reaction accelerators include 1,8-diazabicyclo[5.4.0]undecene formate, octylate, p-toluenesulfonate, o-phthalate, phenol salt or Phenolic novolak resin salts, 1,5-diazabicyclo[4.3.0]nonene formate salts, octylate salts, p-toluenesulfonate salts, o-phthalate salts, phenol salts or phenol novolak resin salts, etc. mentioned.

Examples of imidazole-based reaction accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-methyl-4-ethylimidazole, 2-phenylimidazole, 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 isocyanurate, 2-phenylimidazole isocyanurate, 2-phenyl- 4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and the like. These curing accelerators may be used alone or in combination of two or more.

(adhesive layer)
The adhesive layer according to the present invention comprises the adhesive composition of the present invention.
The adhesive composition that forms the adhesive layer can be cured.
The curing method is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include heat curing.
The thickness of the adhesive layer is not particularly limited and can be appropriately selected depending on the intended purpose. Also, it is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. If the thickness of the adhesive layer is 3 μm or more, sufficient adhesive strength can be exhibited, and if it is 5 μm or more, steps such as the pattern of the printed wiring board can be followed. If the thickness of the adhesive layer is 50 μm or less, the laminate can be made thinner, and if it is 30 μm or less, the resin flow can be accurately controlled.

<Method for producing adhesive layer>
An adhesive layer can be produced by forming a film from the adhesive composition.
The above adhesive composition can be produced by mixing a resin composition containing a modified styrene-based elastomer and a curing agent. The mixing method is not particularly limited as long as the adhesive composition becomes uniform. Since the adhesive composition is preferably used in the form of a solution or dispersion, a solvent is also usually used.
Examples of solvents 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, and isophorone; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and mesitylene; methyl acetate, ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate; -, 3-methoxybutyl acetate; and aliphatic hydrocarbons such as hexane, heptane, cyclohexane, and methylcyclohexane. These solvents may be used alone or in combination of two or more. By adding a small amount of cyclohexanone to toluene, which can dissolve particularly low-polarity resins, the compatibility with the curing agent and the like is improved, and the adhesive layer can be made uniform.
When the adhesive composition is a solvent-containing solution or dispersion (resin varnish), coating on the substrate film and formation of the adhesive layer can be performed smoothly, and an adhesive layer having a desired thickness can be formed. can be obtained easily.
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 moderate, and it is easy to apply 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 substrate film to form a resin varnish layer, and then the resin varnish is applied to the surface of the substrate film. A B-staged adhesive layer can be formed by removing the solvent from the layer. Here, the adhesive layer being in a B-stage state means that the adhesive composition is in 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. It means the state to do.
Here, the method for applying the resin varnish on the substrate film is not particularly limited and can be appropriately selected according to the purpose. 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, a dispensing method, and the like can be mentioned.
The B-stage adhesive layer can be further subjected to heating or the like to form a cured adhesive layer.

<Characteristics of Adhesive Layer>
If the resin flow of the adhesive layer is large, the adhesive layer flows out and blocks the through-holes during the mounting and manufacturing of the coverlay film, printed wiring board, and printed wiring board with shielding film during thermocompression bonding, resulting in electrical continuity. I can't take it. Also, in copper-clad laminates and shield films, resin leakage from the edges during thermocompression bonding and uneven pressure distribution can cause wrinkle patterns due to resin flow. From the viewpoint of preventing these defects, the resin flow of the adhesive layer made of the adhesive composition of the present invention is preferably 0.25 mm or less, more preferably 0.10 mm or less. If the resin flow is 0.25 mm or less, it can be used in a generally used through hole of 0.5 mmφ or more. If the resin flow is 0.10 mm or less, it can be used in through-holes of 0.2 to 0.5 mm in diameter, which are expected to be used in the future, and an effect of preventing wrinkles in copper-clad laminates and shielding films can also be expected.
The dielectric constant (εr) of the adhesive layer obtained by curing the adhesive composition of the present invention at a frequency of 28 GHz is preferably 3 or less, more preferably 2.7 or less. The dielectric loss tangent (tan δ) of the adhesive layer at a frequency of 28 GHz is preferably 0.005 or less, more preferably 0.0025 or less, and even more preferably 0.002 or less.
If the dielectric constant is 3 or less and the dielectric loss tangent is 0.005 or less, it can also be used for high-frequency FPC-related products that require strict electrical characteristics. In addition, if the dielectric constant is 2.7 or less and the dielectric loss tangent is 0.0025 or less, it is possible to satisfy the electrical characteristics expected for the components of 5G compatible high-frequency FPC-related products, and it is equivalent to LCP. , and can be suitably used for 5G high-frequency FPC-related products that have strict requirements for electrical characteristics. Furthermore, if the dielectric loss tangent is 0.002 or less, it is possible to manufacture high-frequency FPC-related products with further improved transmission characteristics.

[Relative permittivity and dielectric loss tangent]
The relative dielectric constant and dielectric loss tangent of the adhesive layer were determined by the open resonator method using a network analyzer MS46122B (manufactured by Anritsu) and an open resonator Fabry-Perot DPS-03 (manufactured by KEYCOM) at a temperature of 23°C. , and a frequency of 28 GHz.

(Laminate)
The laminate of the present invention comprises 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 according to the use of the laminate. For example, when the laminate is used as a coverlay film or a copper clad laminate (CCL), polyimide film, polyetheretherketone film, polyphenylene sulfide film, aramid film, polyethylene naphthalate film, and liquid crystal polymer film can be used. . Among these, polyimide film, polyetheretherketone (PEEK) film, polyethylene naphthalate film, and liquid crystal polymer film are preferred from the viewpoint of adhesion and electrical properties.
It is preferable that the storage elastic modulus of the base film at 200° C. is 1×10 ⁸ or more. Resin flow is accompanied by deformation of the edges of the base film, and the larger the deformation, the greater the resin flow.

In addition, when the laminate of the present invention is used as a bonding sheet, the base film must be a release film, such as polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release treated paper, polyolefin resin. Coated paper, TPX (polymethylpentene) film, fluorine-based resin film, and the like.

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

(coverlay film)
A preferred embodiment of the laminate according to the present invention is a coverlay film.
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 comprises an insulating resin layer and an adhesive layer formed on its surface.
For example, a 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 separate the base film and the adhesive layer.
The thickness of the base film included in the coverlay film is preferably 5 to 100 μm, more preferably 5 to 50 μm, even more preferably 5 to 30 μm. If the thickness of the base film is equal to or less than the above upper limit, the thickness of the coverlay film can be reduced. When the thickness of the substrate 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 the solvent is removed from the resin varnish layer. is removed, a coverlay film having a B-stage adhesive layer formed thereon can be produced.
The drying temperature for removing the solvent is preferably 40 to 250°C, more preferably 70 to 170°C.
Drying is performed by passing the laminate coated with the adhesive composition through a furnace in which hot air drying, far-infrared heating, high-frequency induction heating, or the like is performed.
If necessary, a release film may be laminated on the surface of the adhesive layer for storage or the like. As the releasable film, publicly known films such as polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release treated 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, it is possible for high-speed transmission of electronic devices, and furthermore, it has excellent adhesive stability with electronic devices. Become.

(bonding sheet)
A preferred embodiment of the laminate according to the present invention is a bonding sheet.
The bonding sheet is obtained by forming the adhesive layer on the surface of a release film (base film). Also, the bonding sheet may be in a mode in which an adhesive layer is provided between two release films. When using the bonding sheet, the release film is peeled off before use. As the releasable film, the same one as described in the above section (coverlay film) can be used.
The thickness of the base film included in the bonding sheet is preferably 5 to 100 μm, more preferably 25 to 75 μm, even more preferably 38 to 50 μm. If the thickness of the base film is within the above range, the bonding sheet can be easily manufactured and handled well.
As a method for producing a bonding sheet, for example, there is a method of applying a resin varnish containing the adhesive composition and a solvent to the surface of a release film and drying 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, it is capable of high-speed transmission of electronic devices, and has excellent adhesion stability with electronic devices. .

(Copper clad laminate (CCL))
A preferred embodiment of the laminate according to the present invention is a copper-clad laminate obtained by bonding a copper foil to the adhesive layer in the laminate according to the present invention.
A copper-clad laminate is obtained by laminating copper foil using the above laminate, and is composed of, for example, a substrate film, an adhesive layer and copper foil in this order. In addition, 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 also has excellent adhesion 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 adhesion stability.

As a method for producing a copper-clad laminate, for example, the adhesive layer and copper foil of the laminate are brought into surface contact, thermal lamination is performed at 80° C. to 200° C., and the adhesive layer is cured by after-curing. There is a way. The after-curing conditions can be, for example, 100° C. to 200° C. for 30 minutes to 4 hours in an inert gas atmosphere. In addition, the said copper foil is not specifically limited, Electrolytic copper foil, a rolled copper foil, etc. can be used.

(Printed wiring board)
A preferred embodiment of the laminate according to the present invention is a printed wiring board obtained by laminating copper wiring to the adhesive layer in the laminate according to the present invention.
A printed wiring board is obtained by forming an electronic circuit on the copper-clad laminate.
A printed wiring board is formed by laminating a substrate film and copper wiring using the laminate, and is composed of a substrate film, an adhesive layer, and copper wiring in this order. In addition, 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 using a hot press or the like to attach a coverlay film to a surface having a wiring portion via an adhesive layer.
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 adhesion stability.
As a method for producing the printed wiring board according to the present invention, for example, the adhesive layer of the laminate is brought into contact with the copper wiring, thermal lamination is performed at 80 ° C. to 200 ° C., and the adhesive layer is removed by after-curing. There is a way to harden it. The after-cure conditions can be, for example, 100° C. to 200° C. and 30 minutes to 4 hours. The shape of the copper wiring is not particularly limited, and any suitable shape may be selected as desired.

(shield film)
A preferred embodiment of the laminate according to the present invention is a shield film.
A 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 instruments and causes malfunctions. Also called electromagnetic wave shielding film.
The electromagnetic wave shielding film is formed by laminating an insulating resin layer, a metal layer, and an adhesive layer according to the present invention in this order, for example.
Since the shielding 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.
A printed wiring board with a shielding film is a printed wiring board having a printed circuit on at least one side of a substrate, and the electromagnetic wave shielding film is attached on the printed wiring board.
A printed wiring board with a shield film includes, for example, a printed wiring board, an insulating film adjacent to the surface of the printed wiring board on which the printed circuit is provided, and the electromagnetic wave shielding film.
Since the printed wiring board with a shielding 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 adhesion stability.

Although the present invention will be described in more detail with examples below, 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 Elastomer Containing Carboxy Group)
The trade name “Kraton FG1901” (maleic acid-modified styrene-ethylenebutylene-styrene block copolymer) manufactured by Kraton was used. This copolymer has an acid number of 19 mg KOH/g, a styrene/ethylene butylene ratio of 30/70, and a weight average molecular weight of 81,000.
(Styrenic elastomer containing amino group)
Asahi Kasei Co., Ltd. trade name "Tuftec MP10" (amine-modified styrene-ethylene butylene-styrene copolymer) was used. This copolymer has a styrene/ethylene butylene ratio of 30/70 and a weight average molecular weight of 78,000. The total nitrogen content in this copolymer was 430 ppm (μg/g).
(Styrene-based elastomer containing no carboxyl group)
Asahi Kasei Co., Ltd. trade name "Tuftec P1500" (hydrogenated styrene elastomer) was used. This copolymer has an acid value of 0 mg KOH/g, a styrene/ethylene butylene ratio of 30/70, and a weight average molecular weight of 67,000.
(unmodified styrenic elastomer)
A trade name “Kraton G1651” (styrene-ethylenebutylene-styrene block copolymer) manufactured by Kraton Co., Ltd. was used. This copolymer has an acid number of 0 mg KOH/g, a styrene/ethylene butylene ratio of 33/67, and a weight average molecular weight of 136,700.
(unmodified styrenic elastomer)
A product name "A1535" (hydrogenated styrene-butadiene copolymer) manufactured by Kraton was used. This copolymer has an acid value of 0 mgKOH/g and a weight average molecular weight of 135,700.
(Hardener: epoxy modified resin)
A trade name “Epofriend CT310” (epoxidized styrene-butadiene block copolymer) manufactured by Daicel Corporation was used. This copolymer has a styrene/ethylene butylene ratio of 40/60, a weight average molecular weight of 93,000 and an epoxy equivalent of 2125 g/eq. is.
(Curing agent: organic peroxide)
As the organic peroxide, a peroxyester manufactured by NOF Corporation under the trade name of "PERBUTYL E" was used.
(solvent)
A mixed solvent of toluene and cyclohexanone (mass ratio=97:3) 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. The storage modulus of the base film at 200°C was 5×10 ⁸ .
(electrolytic copper foil)
As the electrolytic copper foil, “TQ-M7-VSP” manufactured by Mitsui Kinzoku Mining Co., Ltd. (electrolytic copper foil, thickness 12 μm, glossy surface Rz 1.27 μm, glossy surface Ra 0.197 μm, glossy surface Rsm 12.95 μm) was used. The surface roughness of the glossy surface is a value determined based on JIS B 0601:2013 (ISO 4287:1997 Amd.1:2009) from the roughness curve measured using a laser microscope. .
(release film)
As the release film, NP75SA (silicone release PET film, 75 μm) manufactured by Panac 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 15% by mass.
Each component constituting the resin composition in the adhesive composition and the MFR of the resin composition are as shown in Table 1. Table 1 also shows the content ratio of the resin composition and the curing agent.
Next, the surface of the base film was subjected to corona treatment.
The resin varnish prepared above was applied to the surface of the base film, dried in an oven at 130° C. for 4 minutes, and the solvent was volatilized to form an adhesive layer (25 μm) to obtain a base film with adhesive. rice field. The adhesive laminate was laminated so that the adhesive layer of the adhesive laminate was in contact with the glossy surface of the electrolytic copper foil, and thermal lamination was performed at 150° C. to obtain an adhesive laminate before curing. The pre-cured adhesive laminate was post-cured at 150° C. for 1 hour to cure the adhesive layer, thereby obtaining a cured adhesive laminate.

The MFR of the resin composition of Example 1 was measured.
The resin flow (mm) of the cured adhesive laminate of Example 1 was measured.
The adhesive strength (N/cm) between the electrodeposited copper foil and the substrate film of the cured adhesive laminate of Example 1 was measured.
The dielectric constant and dielectric loss tangent at a frequency of 28 GHz were also measured for the adhesive layer in the cured adhesive laminate of Example 1.

[MFR of resin composition]
Each component of the resin composition was contained in the ratio shown in Table 1, and these components were dissolved in a solvent to prepare a resin composition varnish having a solid content concentration of 15% by mass. The resin composition varnish is applied on the release film by a roll, and then the film with the coating film is allowed to stand in an oven and dried at 130 ° C. for 4 minutes to form a resin composition film (thickness 50 μm ) was formed. A sample for MFR measurement was prepared by peeling the resin composition film from the release film and cutting it.
The MFR was measured using an extrusion plastometer defined by JIS K6760, and the measurement method was based on the method defined by JIS K7210 (1976). In Example 1, the measurement was performed under the conditions of 200° C. and a load of 21.60 kg.

[Resin flow (mm)]
Three holes with a diameter of 5 mm were punched in a base film with an adhesive (adhesive layer 25 μm, 30 mm×90 mm) using a belt punch.
Laminate the electrodeposited copper foil so that it is in contact with the glossy surface, heat laminate at 150 ° C, press at 180 ° C, 3 MPa, 3 minutes, and check the length of the resin protruding on the copper foil with a microscope (4 points x 3 places ) was measured at 12 points, and the average value was recorded.
Microscope (DIGITAL MICROSCOPE VHX-500 manufactured by KEYENCE): lens magnification 300 times

[Adhesion (N/cm)]
The adhesive strength was measured by cutting the adhesive laminate after curing into a test piece with a width of 25 mm, and measuring the peel speed of 0.3 m/min and the peel angle of 180 according to JIS Z0237:2009 (adhesive tape/adhesive sheet test method). The adhesive force was measured by measuring the peel strength when the electrolytic copper foil was peeled off from the adhesive-attached substrate film fixed to the support at 10°C.

[Solder heat resistance test]
In the solder heat resistance test, the cured adhesive laminate was floated in a solder bath at 288° C. for 10 seconds×3 times with the base film side up, and any abnormal appearance such as swelling or peeling of the adhesive layer was confirmed.
The heat resistance of the laminate was evaluated according to the following evaluation criteria.
◎ No abnormality (no dissolution).
○ Although there was no abnormality in the end, softening of the adhesive layer was observed during the test.
Δ: The adhesive layer was not peeled off, but the adhesive layer was softened and a “stain pattern” was formed.
x: Peeled off.

[Relative permittivity and dielectric loss tangent]
The relative dielectric constant and dielectric loss tangent of the adhesive layer were determined by the open resonator method using a network analyzer MS46122B (manufactured by Anritsu) and an open resonator Fabry-Perot DPS-03 (manufactured by KEYCOM) at a temperature of 23°C. , and a frequency of 28 GHz. For the measurement sample, a resin varnish is applied on the release film by a roll, and then the film with the coating film is left standing in an oven and dried at 110 ° C. for 4 minutes to form a B-stage adhesive layer. (thickness 50 μm). Next, this adhesive layer was thermally laminated at 150° C. so that the adhesive surfaces were in contact with each other to form an uncured adhesive film (thickness: 100 μm). This pre-curing adhesive film (thickness: 100 μm) was placed 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 dielectric constant and dielectric loss tangent of the adhesive layer were measured.

Table 1 shows each measurement result. In addition, in Table 1, "na" indicates that the measurement could not be performed due to no flow.

(Examples 2 to 11)
Laminates of Examples 2 to 11 were produced in the same manner as in Example 1, except that the types and amounts of the components constituting the adhesive layer were changed as shown in Table 1. .
Evaluation similar to Example 1 was performed with respect to the produced laminated body.
Table 1 shows the results.

(Comparative Examples 1 to 5)
Laminates of Comparative Examples 1 to 5 were prepared in the same manner as in Example 1, except that the types and amounts of the components constituting the adhesive layer were changed as shown in Table 1. .
Evaluation similar to Example 1 was performed with respect to the produced laminated body.
Table 1 shows the results.

As shown in the examples, the adhesive layer made of the adhesive composition of the present invention exhibits good electrical properties (dielectric properties) compatible with 5G, and is also excellent in adhesion, heat resistance, and solvent resistance. It is possible to further suppress the resin flow.

A laminate having an adhesive layer comprising 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, laptop computers, and medical instruments. can be used for

Claims

Containing a resin composition containing a modified styrene-based elastomer and a curing agent,
The content of the modified styrene-based elastomer relative to 100 parts by mass of the resin composition is 25 parts by mass or more,
The adhesive composition, wherein the resin composition has a melt flow rate (200° C., load 21.60 kg) of 40 g/10 minutes or less.
The adhesive composition according to claim 1, wherein the resin composition has a melt flow rate (200°C, load of 21.60 kg) of 0.1 g/10 minutes or more.
The adhesive composition according to claim 1 or 2, wherein the content of said curing agent is 25 parts by mass or less with respect to 100 parts by mass of said adhesive composition.
The adhesive composition according to any one of claims 1 to 3, wherein the modified styrene elastomer is a carboxy group-containing styrene elastomer.
The adhesive composition according to any one of claims 1 to 3, wherein the modified styrene-based elastomer is a styrene-based elastomer containing an amino group.
The adhesive composition according to any one of claims 1 to 5, wherein the resin composition contains at least two types of styrene-based elastomers.
The adhesive composition according to any one of claims 1 to 6, wherein the curing agent contains an epoxy resin.
The adhesive composition according to claim 7, wherein the curing agent contains an epoxy-modified styrene-butadiene copolymer.
The adhesive composition according to any one of claims 1 to 8, wherein the resin composition contains a styrene-based elastomer having a weight average molecular weight (Mw) of 100,000 to 500,000.
The adhesive composition according to any one of claims 1 to 9, wherein the curing agent contains an organic peroxide.
With respect to the adhesive layer obtained by curing the adhesive composition according to any one of claims 1 to 10, the adhesive layer has a dielectric constant of 3 or less when measured at a frequency of 28 GHz, and a dielectric loss tangent is 0.005 or less.
a base film;
A laminate comprising an adhesive layer comprising the adhesive composition according to any one of claims 1 to 10 or the adhesive layer according to claim 11.
The laminate according to claim 12, wherein the base film contains polyetheretherketone (PEEK) resin.
A cover lay film with an adhesive layer comprising the laminate according to claim 12 or 13.
A copper clad laminate comprising the laminate according to claim 12 or 13.
A printed wiring board comprising the laminate according to claim 12 or 13.