TW202300607A - Adhesive sheet - Google Patents

Abstract

Provided is an adhesive sheet including a curable adhesive layer, wherein the curable adhesive layer is one formed from a starting material composition comprising a binder resin (A) having a reactive functional group and a crosslinking agent (B) capable of reacting with the (A) ingredient, the (B) ingredient being contained in an amount of 0.1 mass% or larger with respect to the sum of all the active ingredients of the starting material composition. The curable adhesive layer has a gel content of 10 mass% or higher.

Description

Splice

The present invention relates to an adhesive sheet having a curable adhesive layer that is less likely to contaminate its surroundings when subjected to heat treatment such as hot pressing.

In recent years, curable adhesives are sometimes used as materials for forming insulating resin layers, sealant layers, adhesive members, etc. of electronic components and the like.

For example, Patent Document 1 describes a thermosetting adhesive sheet containing epoxy resin, and the storage elastic modulus (x1) at 25° C. of the cured product of the thermosetting adhesive sheet is 1 GPa or more, and, The storage elastic modulus (x2) at 100°C is above 1GPa. Moreover, it is also described in this document that the thermosetting adhesive sheet described in this document can effectively suppress the slight deformation or deviation of the adhered body at high temperature, even if it is used for fixing as the adhered body. In the case of the adherend that is repeatedly slightly deformed, it is not easy to cause peeling over time. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2017-110128.

[Problem to be Solved by the Invention]

When using an adhesive composition, the coating film of an adhesive composition is heat-processed normally. In this case, depending on the processing conditions, there is a possibility that the adhesive components may seep out and cause contamination of the surrounding area.

The present invention is made in view of the above circumstances, and an object of the present invention is to provide an adhesive sheet having a curable adhesive layer that is less likely to contaminate its surroundings when subjected to heat treatment such as hot pressing. [Means to solve the problem]

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems. As a result, it was found that, for an adhesive sheet having a curable adhesive layer, by using a composition containing predetermined components as a raw material composition of the curable adhesive layer and adjusting the gel fraction of the curable adhesive layer to a predetermined range, and can suppress the exudation of adhesive components during heat treatment and prevent the surrounding pollution, so that the present invention has been completed.

Thus, according to this invention, the adhesive sheet of following [1]-[14] is provided. [1] An adhesive sheet having a curable adhesive layer; and the raw material composition of the curable adhesive layer contains the following components (A) and (B), and the active ingredients of the aforementioned raw material composition The total amount is 0.1% by mass or more of the component (B); the gel fraction of the hardening adhesive layer is 10% by mass or more. (A) Component: Binder resin with reactive functional groups (B) component: a cross-linking agent that can react with the aforementioned (A) component [2] The adhesive sheet according to [1], wherein the component (A) is a polyolefin resin. [3] The adhesive sheet according to [1] or [2], wherein the component (A) is an acid-modified resin. [4] The adhesive sheet according to any one of [1] to [3], wherein the component (B) is a compound having an isocyanurate skeleton. [5] The adhesive sheet according to any one of [1] to [4], wherein the component (B) is a compound having two or more isocyanate groups. [6] The adhesive sheet according to any one of [1] to [5], wherein the curable adhesive layer is a layer formed of a raw material composition further containing the following component (C). (C) Component: non-aromatic hardening compound that is liquid at 25°C [7] The adhesive sheet according to [6], wherein the component (C) is a compound having two or more hydrocarbon groups having a double bond at the terminal. [8] The adhesive sheet according to any one of [1] to [7], wherein the curable adhesive layer is a layer formed of a raw material composition further containing the following component (D). (D) Component: polyphenylene ether resin with reactive functional groups [9] The adhesive sheet according to any one of [1] to [8], wherein the curable adhesive layer is a layer formed of a raw material composition further containing the following component (E). (E) Component: cationic polymerization initiator [10] The adhesive sheet according to any one of [1] to [9], wherein the dielectric tangent of the curable adhesive layer at 23°C and a frequency of 1 GHz is less than 0.005. [11] The adhesive sheet according to any one of [1] to [10], wherein the curable adhesive layer has a relative dielectric constant of 3.00 or less at 23° C. and a frequency of 1 GHz. [12] The adhesive sheet according to any one of [1] to [11], wherein the curable adhesive layer is cured at 160° C. for 1 hour to form a gel fraction of 50% by mass or more of hardening. [13] The adhesive sheet according to any one of [1] to [12], which is used for electronic components. [14] The adhesive sheet according to any one of [1] to [12], which is used for a coverlay film. [Efficacy of the invention]

According to the present invention, there is provided an adhesive sheet having a curable adhesive layer that is less likely to contaminate its surroundings when subjected to heat treatment such as hot press treatment.

Regarding the numerical range described in this specification, the upper limit and the lower limit can be combined arbitrarily. For example, when "preferably 30 to 100, more preferably 40 to 80" is described as a numerical range, the range of "30 to 80" or the range of "40 to 100" is also included in the description in this specification. the value range. Furthermore, for example, when the numerical range is described as "preferably 30 or more, more preferably 40 or more, and preferably 100 or less, more preferably 80 or less", the range of "30 to 80" or "40 The range from 100 to 100" is also included in the range of numerical values recorded in this specification. Moreover, as a numerical range described in this specification, for example, description of "60 to 100" means the range of "60 or more and 100 or less". Furthermore, in the regulation of the upper limit value and the lower limit value described in this specification, the numerical range from the lower limit value to the upper limit value can be specified by appropriately selecting and arbitrarily combining the respective options. In addition, various requirements described as preferred aspects described in this specification may be combined in plural.

In this specification, the number average molecular weight (Mn) is obtained by gel permeation chromatography (GPC; Gel Permeation Chromatography) using tetrahydrofuran (THF) as a solvent, and in terms of standard polystyrene. For example, it can be found in the following conditions are measured. [Example of measurement conditions] ・Gel permeation chromatography device: manufactured by Tosoh Co., Ltd., product name "HLC-8020" ·Tube column: Connect "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL" and "TSK gel G1000HXL" in sequence (all manufactured by Tosoh Co., Ltd.) ·Column temperature: 40℃ Developing solvent: tetrahydrofuran ·Flow rate: 1.0mL/min

The adhesive sheet of the present invention has a curable adhesive layer; and, the raw material composition of the aforementioned curable adhesive layer contains the following (A) component and (B) component, and relative to the total active ingredients of the aforementioned raw material composition The amount is 0.1% by mass or more of the component (B), and the gel fraction of the curable adhesive layer is 10% by mass or more. (A) Component: Binder resin with reactive functional groups (B) component: a cross-linking agent that can react with the aforementioned (A) component In this specification, the so-called "active ingredient" refers to an ingredient in a composition, and refers to an ingredient other than a solvent.

[Raw material composition of curable adhesive layer] The raw material composition constituting the curable adhesive layer of the adhesive sheet of the present invention contains the above-mentioned (A) component and (B) component, and the content of (B) component is adjusted to 0.1% by mass or more.

The crosslinking agent (B) is a compound that can react with the binder resin (A), so it is possible to combine the binder resin (A) and the crosslinking agent in the coating film (curable adhesive layer) obtained by coating the raw material composition. The agent (B) reacts to build a cross-linked structure in the curable adhesive layer. As will be described later, by utilizing this reaction, it is possible to efficiently form a curable adhesive layer having a gel fraction of 10% by mass or more. In addition, in this specification, the crosslinking reaction which binder resin (A) and a crosslinking agent (B) participate may describe as "hardening reaction (I)."

The raw material composition may contain curable components other than the binder resin (A) and the crosslinking agent (B) (hereinafter sometimes referred to as "hardenable component (X)")".

The hardening component (X) may be a compound that participates in the hardening reaction (I), or may be a compound that does not participate in the hardening reaction (I). The curable component (X) is preferably a compound that does not participate in the hardening reaction (I) in terms of reliably performing multiple curing reactions and more reliably suppressing the bleeding of the adhesive component in the curable adhesive layer. . That is, when the curable component (X) is a compound that participates in the hardening reaction (I), the step of producing the adhesive sheet of the present invention due to the construction of a crosslinked structure in the curable adhesive layer, and the use of the present invention Adhesive sheet is the step of bonding the two substrates more firmly. These two steps require the hardening reaction (I), so it is necessary to start the hardening reaction (I) in order to build a cross-linked structure in the hardening adhesive layer. Stopping for a moment, the hardening reaction needs to be highly controlled (I). On the other hand, when the curable component (X) is a compound that does not participate in the hardening reaction (I), even if the hardening reaction (I) is almost completed, the adhesive layer has hardening derived from the hardening component (X). Therefore, the hardening property can be used to carry out the step of bonding the two adherends more firmly. Thus, by using a raw material composition containing a curable component (X) that does not participate in the curing reaction (I), the adhesive sheet of the present invention can be efficiently produced without controlling the curing reaction (I) to a high degree.

In this specification, the curing reaction in which the curable component (X) that does not participate in the curing reaction (I) participates may be described as "curing reaction (II)".

Examples of the curable component (X) include the following (C)component, (D)component, and (F)component. (C) Component: non-aromatic hardening compound that is liquid at 25°C (D) Component: polyphenylene ether resin with reactive functional groups (F) Component: Silane coupling agent

When the curing reaction (I) or curing reaction (II) is a cationic polymerization reaction, the raw material composition used in one aspect of the present invention may further contain the following component (E). Component (E): Cationic polymerization initiator In addition, the raw material composition used in one aspect of the present invention may further contain components other than the above-mentioned (A) component to (F) component within the range that does not impair the efficacy of the present invention.

In the raw material composition used in one aspect of the present invention, the total content of (A) component and (B) component can be set to 40% by mass relative to the total amount (100% by mass) of active ingredients of the raw material composition More than, 50 mass % or more, 60 mass % or more, 65 mass % or more, or 70 mass % or more, and can also be set to 100 mass % or less, 99 mass % or less, 95 mass % or less, 90 mass % or less, 85 mass % or less than 80% by mass.

In the raw material composition used in one aspect of the present invention, the total content of components (A) to (E) can be set to 45% by mass relative to the total amount (100% by mass) of active ingredients of the raw material composition More than, 55 mass % or more, 65 mass % or more, 75 mass % or more, 80 mass % or more, 85 mass % or more, 90 mass % or more, or 95 mass % or more, and can also be 100 mass % or less, 99.9 mass % or less than 99.8% by mass.

In the raw material composition used in one aspect of the present invention, the total content of (A) component to (F) component can be set to 45% by mass to 100% by mass, 55% by mass or more, 65% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more, and can also be set to 100% by mass or less, 99.9% by mass Mass % or less or 99.8 mass % or less.

[Component (A): Binder resin with reactive functional groups] The raw material composition (hereinafter sometimes simply referred to as "raw material composition") as a forming material of the curable adhesive layer contains an adhesive resin having a reactive functional group (hereinafter sometimes referred to as "adhesive resin (A)") ) as (A) component. By using a raw material composition containing the adhesive resin (A), it becomes easy to form a curable adhesive layer that does not easily contaminate the surrounding area when subjected to heat treatment such as hot press treatment. Binder resin (A) can be used individually by 1 type or in combination of 2 or more types.

The number average molecular weight (Mn) of the binder resin (A) is not particularly limited, but it is usually 10,000 or more in terms of being easy to form a curable adhesive layer that is less likely to contaminate the surrounding area when subjected to heat treatment such as hot pressing treatment. Preferably it is 10,000 to 150,000, more preferably 10,000 to 100,000. The number average molecular weight (Mn) of the binder resin (A) can be obtained by performing gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, and calculated in terms of standard polystyrene. As the specific measurement conditions, the above described in the text.

The content of the binder resin (A) contained in the raw material composition relative to the total amount of active ingredients (100% by mass) of the raw material composition (when two or more kinds of binder resins (A) are contained, these binder resins The total amount of (A)) is preferably at least 50% by mass, more preferably at least 60% by mass, still more preferably at least 65% by mass, more preferably at most 95% by mass, more preferably at most 90% by mass, even more preferably It is 85 mass % or less, More preferably, it is 80 mass % or less. When the content of the binder resin (A) is 50% by mass or more, it is easy to form a curable adhesive layer that does not easily contaminate the surroundings when subjected to heat treatment such as hot press treatment. If the content of the binder resin (A) is 95% by mass or less, low dielectric properties are easily formed (in this specification, the so-called "low dielectric properties" means "low dielectric constant and low dielectric tangent") Excellent hardening adhesive layer.

Examples of the binder resin (A) include polyolefin-based resins, phenoxy-based resins, polyimide-based resins, polyamideimide-based resins, polyvinyl butyral-based resins, and polycarbonate resins. Department of resin, etc. Among these, polyolefin-based resins are preferable as the binder resin (A). When the adhesive resin (A) is a polyolefin-based resin, it is easy to form a curable adhesive layer excellent in low dielectric properties.

In addition, when the (A) component is a raw material composition of a polyolefin resin, this raw material composition may contain other binder resins other than a polyolefin resin as another component. In the aforementioned raw material composition, the content of other binder resins is preferably from 0 to 50 parts by mass, more preferably from 0 to 30 parts by mass, and even more preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass.

The term "polyolefin resin" refers to a polymer containing repeating units derived from olefin monomers. Polyolefin-based resins may be polymers composed only of repeating units derived from olefin-based monomers, or may be composed of repeating units derived from olefin-based monomers and monomers that can be copolymerized with olefin-based monomers A polymer composed of repeating units.

The olefin-based monomer is preferably an α-olefin having 2 to 8 carbon atoms, preferably ethylene, propylene, 1-butene, isobutene or 1-hexene, further preferably ethylene or propylene. These olefinic monomers may be used alone or in combination of two or more. Vinyl acetate, (meth)acrylate, styrene, etc. are mentioned as a monomer copolymerizable with an olefin type monomer. Here, "(meth)acrylic acid" means acrylic acid or methacrylic acid (the same applies hereinafter). These "monomers copolymerizable with olefin-based monomers" can be used alone or in combination of two or more.

Examples of polyolefin-based resins include ultra-low-density polyethylene (VLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene, Polypropylene (PP), ethylene-propylene copolymer, olefin-based elastomer (TPO), ethylene-vinyl acetate copolymer (EVA), ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer things etc.

Examples of the reactive functional groups contained in the binder resin (A) include carboxyl groups, carboxylic acid anhydride groups, carboxylate groups, hydroxyl groups, epoxy groups, amido groups, ammonium groups, nitrile groups, amino groups, and imide groups. Amino group, isocyanate group, acetyl group, thiol group, ether group, thioether group, sulfonyl group, phosphonyl group, nitro group, carbamate group, halogen atom, alkoxysilyl group, etc.

The binder resin (A) is preferably a modified resin. The modified resin is a resin with reactive functional groups introduced by using a modifier to modify the resin as a precursor. The modifier used in the modification treatment of the binder resin is a compound having a reactive functional group in the molecule. As a reactive functional group, what was demonstrated above is mentioned.

Examples of the modified resin include resins into which acid groups have been introduced (acid-modified resins), or resins into which hydroxyl groups have been introduced, and acid-modified resins are preferred. Among the acid-modified resins, those introduced with an acid anhydride structure are also preferable. By using an acid-modified resin as (A) component, it becomes easy to form the curable adhesive layer excellent in low dielectric property. Furthermore, by using a resin into which an acid anhydride structure is introduced as an acid-modified resin, it tends to be easy to maintain a long service life of the raw material composition.

When the component (A) is a raw material composition of an acid-modified resin, the raw material composition may contain other binder resins other than the acid-modified resin as other components. In the aforementioned raw material composition, the content of other binder resins is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, and even more preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass.

Examples of acid-modified resins include: reacting unsaturated carboxylic acid or unsaturated carboxylic acid anhydride (hereinafter sometimes referred to as "unsaturated carboxylic acid, etc.") with the resin to introduce (graft modification) carboxyl group or carboxylic anhydride base resin.

Examples of unsaturated carboxylic acids that react with resins include unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, and aconitic acid; Unsaturated carboxylic anhydrides such as maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, etc. These unsaturated carboxylic anhydrides may be used alone or in combination of two or more. Among these, maleic anhydride is preferred at the point that it is easy to form a curable adhesive layer that can obtain a cured product with higher adhesive strength.

With respect to 100 parts by mass of the resin, the amount of the unsaturated carboxylic acid etc. which reacts with the resin is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, further preferably 0.2 to 1 part by mass . By using the acid-modified resin thus obtained, it is easy to form a curable adhesive layer that can obtain a cured product with higher adhesive strength.

The method of introducing the unsaturated carboxylic acid unit or the unsaturated carboxylic anhydride unit into the resin is not particularly limited. For example, the method of graft-copolymerizing unsaturated carboxylic acid and the like with the resin by the following method: in the presence of free radical generators such as organic peroxides and azonitriles, resin and unsaturated carboxylic acid A method in which an acid, etc. is heated and melted above the melting point of the resin and reacted; or a method in which a resin and an unsaturated carboxylic acid, etc. are dissolved in an organic solvent, and then heated and stirred in the presence of a radical generator to react.

The binder resin (A) is preferably a modified polyolefin resin, more preferably an acid modified polyolefin resin. When the adhesive resin (A) is an acid-modified polyolefin resin, it is easy to form a curable adhesive layer excellent in low dielectric properties and low contamination.

The modified polyolefin-based resin is a polyolefin-based resin with reactive functional groups introduced therein, which is obtained by modifying the polyolefin-based resin as a precursor with a modifying agent.

When the component (A) is a raw material composition of an acid-modified polyolefin resin, the raw material composition may contain other binder resins other than the acid-modified polyolefin resin as other components. In the aforementioned raw material composition, the content of other binder resins is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, relative to 100 parts by mass of the total amount of the acid-modified polyolefin resin , and more preferably 0 to 10 parts by mass, and more preferably 0 to 5 parts by mass.

[Component (B): Cross-linking agent that can react with component (A)] The raw material composition contains a crosslinking agent (hereinafter sometimes described as "crosslinking agent (B)") capable of reacting with (A) component as (B) component. By using a raw material composition containing a crosslinking agent (B), it becomes easy to form a curable adhesive layer that does not easily contaminate the surrounding area when subjected to heat treatment such as hot press treatment. In addition, the crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more types.

The molecular weight of the crosslinking agent (B) is preferably 1000 or less, more preferably 800 or less, still more preferably 700 or less, still more preferably 600 or less, especially preferably 500 or less. When the molecular weight of the crosslinking agent (B) is 1000 or less, the collision probability of the reaction with the component (A) is increased, and the crosslinking structure is easily formed, and it can be adjusted to be easy to form when heat treatment such as hot pressing treatment is not easy to contaminate the surroundings The raw material composition of the curable adhesive layer. The lower limit of the molecular weight of the crosslinking agent (B) is not particularly present, and is usually 100 or more, preferably 200 or more. Furthermore, the molecular weight of the crosslinking agent (B) is a formula weight determined by the structural formula of the compound used as the crosslinking agent (B).

The content of the crosslinking agent (B) relative to the total amount of active ingredients (100% by mass) of the raw material composition (when two or more crosslinking agents (B) are included is the total amount of these crosslinking agents (B) ) is at least 0.1% by mass, preferably at least 0.2% by mass, more preferably at least 0.3% by mass, more preferably at least 0.5% by mass, even more preferably at least 0.7% by mass, especially preferably at least 0.9% by mass, and more preferably Preferably, it is 5 mass % or less, More preferably, it is 4 mass % or less, More preferably, it is 3 mass % or less, More preferably, it is 2 mass % or less. When the content of the crosslinking agent (B) is 0.1% by mass or more relative to the total amount of active ingredients of the raw material composition, it is easy to form a curable adhesive layer that does not easily contaminate the surrounding area when subjected to heat treatment such as hot pressing. And when content of a crosslinking agent (B) is 5 mass % or less with respect to the active ingredient total amount of a raw material composition, it becomes easy to form a curable adhesive layer excellent in low dielectric property.

The content of the crosslinking agent (B) (the total amount of these crosslinking agents (B) when two or more kinds of crosslinking agents (B) are included) is preferably 0.1 parts by mass relative to 100 parts by mass of the component (A) More than 0.3 parts by mass, more preferably 0.5 parts by mass, more preferably 0.8 parts by mass, more preferably 1.2 parts by mass, more preferably 10 parts by mass or less, more preferably 7 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 3 parts by mass or less.

The crosslinking agent (B) is a compound which can react with (A) component. Therefore, as the crosslinking agent (B), it is necessary to appropriately select a compound having a reactive group or a reactive site that is reactive to the reactive functional group in the binder resin (A). For example, as a crosslinking agent (B), an isocyanate type crosslinking agent, an epoxy type crosslinking agent, a metal chelate type crosslinking agent, an aziridine type crosslinking agent etc. can be used. Among these, from the viewpoint of storage stability, one or more types selected from isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-based crosslinking agents are preferred. Moreover, in one aspect of the present invention, for example, when the binder resin (A) is an acid-modified resin, and the reactive functional group in the binder resin (A) is a carboxyl group or a carboxylic acid anhydride group, as a crosslinking The agent (B) is preferably at least one selected from isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-based crosslinking agents.

The isocyanate-based crosslinking agent is a compound having two or more isocyanate groups in the molecule. Examples of isocyanate-based crosslinking agents include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate, 1,5-pentamethylene diisocyanate, 1 , 6-hexamethylene diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, tetramethylbenzene Dimethyl diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, adducts of these polyisocyanate compounds and polyol compounds such as trimethylolpropane, and biuret products of these polyisocyanate compounds Or isocyanurate etc.

The epoxy-based crosslinking agent is a compound having two or more epoxy groups in the molecule. Examples of epoxy-based crosslinking agents include: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-meta Xylylenediamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidylamine, etc.

The metal chelate type crosslinking agent is a chelate compound having a metal ion functioning as a crosslinking point. As a metal chelate type crosslinking agent, the metal chelate compound whose metal ion is aluminum ion, zirconium ion, titanium ion, zinc ion, iron ion, tin ion, etc. can be used, for example. Among these, aluminum chelate compounds are preferred.

Examples of aluminum chelate compounds include: tris(acetylacetonate)aluminum, acetylacetonate bis(ethyl acetate)aluminum, diisopropoxymonoacetylacetate oleyl aluminum, monoisopropoxybis Acetyl oleyl acetate, aluminum, etc.

In one aspect of the present invention, the crosslinking agent (B) is preferably a compound having an isocyanurate skeleton, more preferably a compound having an isocyanurate skeleton and two or more isocyanate groups . When the crosslinking agent (B) is a compound having an isocyanurate skeleton, it becomes easy to form a curable adhesive layer excellent in low dielectric properties. Furthermore, when the component (B) is a raw material composition of a compound having an isocyanurate skeleton, the raw material composition may contain other crosslinking agents other than the compound having an isocyanurate skeleton. as other ingredients. In the aforementioned raw material composition, the content of other crosslinking agents is preferably 0 to 100 parts by mass, more preferably 0 to 50 parts by mass, relative to 100 parts by mass of the total amount of the compound having an isocyanurate skeleton. parts by mass, more preferably 0 to 30 parts by mass, more preferably 0 to 10 parts by mass, especially preferably 0 to 5 parts by mass.

In one aspect of the present invention, the crosslinking agent (B) is preferably a compound having two or more isocyanate groups from the viewpoint of easily forming a curable adhesive layer excellent in low dielectric properties. The isocyanate-based crosslinking agent is more preferably an isocyanurate product of a polyisocyanate compound, and more preferably an isocyanurate product of 1,5-pentamethylene diisocyanate [1,3,5-tri(5 -isocyanate pentyl)-1,3,5-triazine-2,4,6-trione] or the isocyanurate of 1,6-hexamethylene diisocyanate [1,3,5-trione (6-isocyanatohexyl)-1,3,5-triazine-2,4,6-trione]. Furthermore, when the component (B) is a raw material composition of an isocyanate-based cross-linking agent, the raw material composition may contain other cross-linking agents other than the isocyanate-based cross-linking agent as other components. In the aforementioned raw material composition, the content of other crosslinking agents is preferably 0 to 100 parts by mass, more preferably 0 to 50 parts by mass, relative to 100 parts by mass of the total amount of the aforementioned isocyanate-based crosslinking agent, More preferably, it is 0 to 30 parts by mass, Still more preferably, it is 0 to 10 parts by mass, Most preferably, it is 0 to 5 parts by mass.

In one aspect of the present invention, the crosslinking agent (B) is preferably an epoxy-based crosslinking agent layer in terms of being easy to form a curable adhesive layer that does not easily contaminate the surrounding area when subjected to heat treatment such as hot pressing. joint agent. When the component (B) is a raw material composition of an epoxy-based crosslinking agent, the raw material composition may contain other crosslinking agents other than the epoxy-based crosslinking agent as other components. In the aforementioned raw material composition, the content of other crosslinking agents is preferably 0 to 100 parts by mass, more preferably 0 to 50 parts by mass, relative to the total amount of 100 parts by mass of the epoxy-based crosslinking agent, More preferably, it is 0 to 30 parts by mass, Still more preferably, it is 0 to 10 parts by mass, Most preferably, it is 0 to 5 parts by mass.

Since the crosslinking agent (B) is a compound that can react with the binder resin (A), it is possible to combine the binder resin (A) and the crosslinking agent in the coating film (curable adhesive layer) obtained by coating the raw material composition. The linking agent (B) reacts to build a cross-linked structure in the curable adhesive layer. As will be described later, by utilizing this reaction, a curable adhesive layer with a gel fraction of 10% by mass or more can be formed more efficiently, and it is easy to form a curable adhesive layer that does not easily contaminate the surroundings when subjected to heat treatment such as hot pressing. Adhesive layer.

[Component (C): non-aromatic hardening compound that is liquid at 25°C] The component (C) is a non-aromatic curable compound (hereinafter sometimes referred to as "hardenable compound (C)") that is liquid at 25°C. The curable compound (C) can be used individually by 1 type or in combination of 2 or more types.

The curable compound (C) is a curable compound. Therefore, when the curable compound (C) is a curable component (X) that does not participate in the curing reaction (I), the curable adhesive layer containing the curable compound (C) has ) of hardening.

The curable compound (C) is a liquid compound at 25°C. Therefore, when the curable compound (C) is a curable component (X) that does not participate in the curing reaction (I), the curable adhesive layer containing the curable compound (C) has a good performance during lamination. Wet spreadability and layer suitability are more excellent. The term "liquid at 25°C" means fluidity at 25°C. For example, a compound that is liquid at 25°C is a compound having a viscosity of 2 mPa·s to 10000 mPa·s measured at 25°C and 1.0 rpm using an E-type viscometer.

The hardening compound (C) is a non-aromatic compound. The term "non-aromatic compound" means a compound that does not have an aromatic ring. Since the curable compound (C) is a non-aromatic compound, the curable adhesive layer containing the curable compound (C) tends to be more excellent in low dielectric properties.

The curable compound (C) is preferably a compound having a heterocyclic skeleton. When the curable compound (C) is a compound having a heterocyclic skeleton, it is easy to form a curable adhesive layer capable of obtaining a cured product more excellent in adhesive strength and low dielectric properties. When the (C) component is a raw material composition of a compound having a heterocyclic skeleton, the raw material composition may contain other curable compounds other than the compound having a heterocyclic skeleton as other components. In the aforementioned raw material composition, the content of other curable compounds is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, relative to 100 parts by mass of the total amount of the compound having a heterocyclic skeleton. , and more preferably 0 to 10 parts by mass, and more preferably 0 to 5 parts by mass. As a heterocyclic skeleton, an isocyanurate skeleton or a glycol urea skeleton is mentioned. The heterocyclic skeleton preferably has an n-th rotation axis as a symmetry element. A curable adhesive layer containing such a curable compound (C) having a heterocyclic skeleton tends to be more excellent in low dielectric properties.

The molecular weight of the curable compound (C) is preferably at most 1,000, more preferably at most 800, further preferably at most 650, even more preferably at most 500. Curable compounds with a molecular weight of 1,000 or less tend to satisfy the requirement of being liquid at 25°C. Furthermore, the molecular weight of the curable compound (C) is preferably at least 100, more preferably at least 200, and still more preferably at least 275. The curable compound (C) with a molecular weight of 100 or more is not easily volatilized even when heat-treated when forming a curable adhesive layer or using a curable adhesive layer. Therefore, by adding a curable compound with a high molecular weight to the curable adhesive layer Compound (C), and it is easy to obtain a hardened product having the target physical properties.

Examples of the curable compound (C) include compounds having two or more hydrocarbon groups having a double bond at the terminal (hereinafter, this compound may be referred to as "hardenable compound (C')"). By using the curable compound (C') as the curable compound (C), it is easy to form a curable adhesive layer capable of obtaining a cured product having more excellent low dielectric properties. When the component (C) is a raw material composition of the curable compound (C'), the raw material composition may contain other curable compounds other than the curable compound (C') as other components. In the aforementioned raw material composition, the content of the other curable compound is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, relative to 100 parts by mass of the total amount of the aforementioned curable compound (C'). parts, more preferably 0 to 10 parts by mass, and more preferably 0 to 5 parts by mass.

The carbon number of the hydrocarbon group having a double bond at the terminal contained in the curable compound (C') is preferably 2-10, more preferably 2-5. Examples of the hydrocarbon group having a double bond at the terminal include: vinyl, allyl, 3-butenyl, 4-pentenyl, 5-hexenyl, isopropenyl, 1-methyl-2-propenyl , Vinylbenzyl, vinylnaphthyl, etc. Among these, an allyl group is preferable.

The number of hydrocarbon groups having a double bond at the terminal contained in the curable compound (C') is 2 or more. When the number of hydrocarbon groups having a double bond at the terminal is 2 or more, it is easy to form a curable adhesive layer that can obtain a cured product having better adhesive strength or heat resistance. Furthermore, the occurrence of cracks in the cured product tends to be suppressed by appropriately loosening the cross-linked structure formed in the cured product. Therefore, the number of hydrocarbon groups having a double bond at the terminal is preferably 2 to 4, more preferably 2.

Examples of the curable compound (C') include a curable compound (C') having an isocyanurate skeleton and a curable compound (C') having a glycoluril skeleton. Examples of the curable compound (C') having an isocyanurate skeleton include compounds represented by the following formula (1) or formula (2).

In formula (1), R ¹ and R ² independently represent a hydrocarbon group having a double bond at the end, and R ³ represents a saturated hydrocarbon group with 1 to 15 carbons, or an alkyl group substituted with an alkoxy group with 1 to 15 carbons. In formula (2), R ⁴ to R ⁶ each independently represent a hydrocarbon group having a double bond at the end.

The hydrocarbon group having a double bond at the terminal represented by R ¹ , R ² , R ⁴ , R ⁵ , and R ⁶ is as described above.

The carbon number of the saturated hydrocarbon group represented by R ³ is 1-15, preferably 5-15, more preferably 8-15. Examples of the saturated hydrocarbon group represented by ^R include: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, second-butyl, isobutyl, n-pentyl, n-hexyl , n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, etc.

The carbon number of the alkoxy-substituted alkyl represented by R ³ is 2-15, preferably 2-12, more preferably 3-10. Examples of the alkoxy-substituted alkyl group represented by ^R3 include methoxymethyl, ethoxymethyl, 2-methoxyethoxymethyl, benzyloxymethyl, and the like.

Examples of the curable compound (C') having a glycoluril skeleton include compounds represented by the following formula (3).

In formula (3), R ⁷ to R ¹⁰ each independently represent a hydrocarbon group having 1 to 15 carbon atoms, and at least two of these are hydrocarbon groups having a double bond at the terminal. R ¹¹ and R ¹² represent a hydrogen atom or a saturated hydrocarbon group with 1 to 15 carbons.

Among these, the curable compound (C') is preferably a compound having an isocyanurate skeleton, more preferably It is a compound represented by formula (1), and it is more preferably a compound represented by the following formula.

In the formula, R represents a saturated hydrocarbon group having 5 to 15 carbons, preferably a saturated hydrocarbon group having 8 to 15 carbons.

When the raw material composition contains a hardening compound (C), the content of the hardening compound (C) (when two or more hardening compounds (C) is the total amount of these curable compounds (C), preferably at least 5% by mass, more preferably at least 7% by mass, still more preferably at least 8.5% by mass, and more preferably at most 25% by mass, more preferably at least 25% by mass. Preferably, it is 20 mass % or less, More preferably, it is 15 mass % or less. When the content of the curable compound (C) is 5% by mass or more in the total amount of active ingredients of the raw material composition, it is easy to form a curable adhesive layer capable of obtaining a cured product excellent in adhesive strength. When the content of the curable compound (C) is 25% by mass or less in the total amount of active ingredients of the raw material composition, it is easy to form a curable adhesive layer capable of obtaining a cured product excellent in low dielectric properties.

When the raw material composition used in one aspect of the present invention contains a curable compound (C), the content of the curable compound (C) (when two or more curable compounds are included) is 100 parts by mass of the component (A). When the compound (C) is the total amount of these curable compounds (C), it is preferably at least 3 parts by mass, more preferably at least 5 parts by mass, still more preferably at least 7 parts by mass, still more preferably at least 10 parts by mass, Moreover, it is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, still more preferably 20 parts by mass or less, still more preferably 16 parts by mass or less.

[Component (D): Polyphenylene ether resin with reactive functional groups] The component (D) is a polyphenylene ether resin (hereinafter sometimes referred to as "polyphenylene ether resin (D)") having a reactive functional group. The polyphenylene ether resin refers to a resin having a polyphenylene skeleton in the main chain. The so-called polyphenylene skeleton refers to a skeleton having a repeating unit represented by the following formula, or a repeating unit in which hydrogen atoms in the above formula are substituted.

The polyphenylene ether resin (D) is a compound having a polyphenylene ether skeleton and reactive functional groups. Since the polyphenylene ether resin (D) has a polyphenylene ether skeleton, the curable adhesive layer system containing the polyphenylene ether resin (D) has excellent low dielectric properties. Furthermore, since the polyphenylene ether resin (D) has a reactive functional group, the cured product of the curable adhesive layer containing the polyphenylene ether resin (D) is excellent in heat resistance. The polyphenylene ether resin (D) may be used alone or in combination of two or more.

Examples of the polyphenylene ether skeleton in the polyphenylene ether resin (D) include skeletons represented by the following formula (4).

In formula (4), X is a divalent group represented by the following formula (5) or formula (6), Y is independently a divalent group represented by the following formula (7), and a and b are 0 to 100 Integers, at least one of a and b is 1 or more. * indicates a bonding site (the same applies hereinafter).

In formula (5), R ¹³ to R ²⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, preferably a hydrogen atom or a methyl group.

In formula (6), R ²¹ to R ²⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, preferably a hydrogen atom or a methyl group. A represents a linear, branched or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

In formula (7), R ²⁹ to R ³² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, preferably a hydrogen atom or a methyl group.

Examples of the polyphenylene ether skeleton in the polyphenylene ether resin (D) include skeletons represented by the following formula (8).

(a及b為0至100之整數，a與b的至少任一者為1以上)。

(a and b are integers from 0 to 100, and at least one of a and b is 1 or more).

Examples of reactive functional groups in the polyphenylene ether resin (D) include vinyl, allyl, acryl, methacryl, cyclopentenyl, vinylbenzyl, vinylnaphthyl, etc. A group with an ethylenically unsaturated bond; an epoxy group; a hydroxyl group, etc. Among these, the reactive functional group is preferably a group having an ethylenically unsaturated bond, more preferably a vinylbenzyl group, from the viewpoint of easily obtaining a cured product excellent in low dielectric properties.

The polyphenylene ether resin (D) is preferably a resin having a reactive functional group at both ends of the polyphenylene ether skeleton in terms of being easy to obtain a cured product having excellent low dielectric properties. In the case where the component (D) is a raw material composition of a resin having reactive functional groups at both ends of the polyphenylene ether skeleton, the raw material composition may contain reactive functional groups at both ends of the polyphenylene ether skeleton. Other polyphenylene ether resins other than resins with functional groups are used as other components. In the aforementioned raw material composition, the content of other polyphenylene ether resins is preferably 0 to 50 parts by mass relative to the total amount of 100 parts by mass of the aforementioned resin having reactive functional groups at both ends of the polyphenylene ether skeleton, More preferably, it is 0-30 mass parts, More preferably, it is 0-10 mass parts, More preferably, it is 0-5 mass parts.

The polyphenylene ether resin (D) can be obtained by introducing a reactive functional group into a terminal after forming a polyphenylene ether skeleton. For example, a polyphenylene ether resin (D) having vinylbenzyl groups as reactive functional groups at both ends can be obtained by reacting a difunctional phenolic compound with a monofunctional phenolic compound to obtain a polyphenylene ether resin (D) having phenolic properties at both ends. After polymerizing the hydroxyl groups, the terminal phenolic hydroxyl groups were vinylbenzyl etherified using 4-(chloromethyl)styrene.

As polyphenylene ether resin (D), the compound represented by following formula (9) is mentioned.

(上述式中，a及b為0至100之整數，a與b中的至少任一者為1以上)。

(In the above formula, a and b are integers from 0 to 100, and at least one of a and b is 1 or more).

In the case where component (D) is a raw material composition of a compound represented by the above formula (9), the raw material composition may contain other polyphenylene ether resins other than the compound represented by the above formula (9) as other Element. In the aforementioned raw material composition, the content of other polyphenylene ether resins is preferably from 0 parts by mass to 50 parts by mass, more preferably from 0 parts by mass to 100 parts by mass of the total amount of the compound represented by the above formula (9). 30 parts by mass, more preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass.

The number average molecular weight (Mn) of the polyphenylene ether resin (D) is preferably from 500 to 5,000, more preferably from 500 to 3,000, still more preferably from 700 to 2,500, still more preferably from 1,000 to 2,000. The number average molecular weight (Mn) of polyphenylene ether resin (D) can be obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, and calculated in terms of standard polystyrene. As specific measurement conditions, As mentioned above.

In the case where the raw material composition contains polyphenylene ether resin (D), the content of polyphenylene ether resin (D) (when including two or more ( In the case of the D) component, the total amount of these (D) components) is preferably at least 1% by mass, more preferably at least 5% by mass, still more preferably at least 10% by mass, still more preferably at least 15% by mass, and more preferably It is 30 mass % or less, More preferably, it is 25 mass % or less. When the content of the polyphenylene ether resin (D) is 1% by mass or more in the total amount of active ingredients of the raw material composition, it is easy to form a curable adhesive layer capable of obtaining a cured product excellent in low dielectric properties. When the content of the polyphenylene ether resin (D) is 30% by mass or less in the total active ingredients of the raw material composition, it is easy to form a curable adhesive layer excellent in adhesion.

In the case where the raw material composition used in one aspect of the present invention contains polyphenylene ether resin (D), the content of polyphenylene ether resin (D) relative to 100 parts by mass of component (A) (when containing two or more In the case of the (D) component, the total amount of these (D) components) is preferably at least 5 parts by mass, more preferably at least 10 parts by mass, further preferably at least 15 parts by mass, further preferably at least 20 parts by mass, and more preferably Preferably, it is 50 mass parts or less, More preferably, it is 40 mass parts or less, More preferably, it is 35 mass parts or less, More preferably, it is 30 mass parts or less.

[(F) component: silane coupling agent] The raw material composition may contain a silane coupling agent (F) as a curable component (X). A silane coupling agent (F) can be used individually by 1 type or in combination of 2 or more types.

As the silane coupling agent (F), known silane coupling agents can be used. Among them, organosilicon compounds having at least one alkoxysilyl group in the molecule are preferred. Examples of the silane coupling agent (F) include: 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyl Oxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, etc. Silane coupling agent; vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, trichlorovinylsilane, vinyl tri(2 -Methoxyethoxy)silane and other silane coupling agents with vinyl groups; 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 8-glycidyloxyoctyltrimethoxysilane, etc. Mixture; p-styryltrimethoxysilane, p-styryltriethoxysilane and other styryl-based silane coupling agents; N-(2-aminoethyl)-3-aminopropylmethyl di Methoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, hydrochloride of N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, etc. have amino groups silane coupling agent; 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane and other silane coupling agents with ureido groups; 3-chloropropyltrimethoxysilane, 3-chloropropyl silane coupling agents with halogen atoms such as triethoxysilane; silane coupling agents with mercapto groups such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; bis(trimethoxy Silane coupling agents with sulfide groups such as silylpropyl) tetrasulfide and bis(triethoxysilylpropyl) tetrasulfide; 3-isocyanate propyl trimethoxysilane, 3-isocyanate propyl triethyl Silane coupling agents with isocyanate groups such as oxysilane; silane coupling agents with allyl groups such as allyltrichlorosilane, allyltriethoxysilane, and allyltrimethoxysilane; 3-hydroxypropyl Silane coupling agents with hydroxyl groups such as trimethoxysilane and 3-hydroxypropyltriethoxysilane.

When the raw material composition contains a silane coupling agent (F), the content of the silane coupling agent (F) relative to the total amount of active ingredients (100% by mass) of the raw material composition (when two or more silane coupling agents are included (F) is the total amount of these silane coupling agents (F)) is preferably at least 0.01% by mass, more preferably at least 0.05% by mass, further preferably at least 0.08% by mass, and is more preferably at most 5% by mass, and more preferably at least 0.08% by mass. Preferably, it is 3 mass % or less, More preferably, it is 1 mass % or less, More preferably, it is 0.5 mass % or less. When the content of the silane coupling agent (F) is 0.01% by mass or more in the total amount of active ingredients of the raw material composition, it is easy to form a curable adhesive layer capable of obtaining a cured product having excellent adhesiveness after a high-temperature, high-humidity test. When the content of the silane coupling agent (F) is 5% by mass or less in the total amount of active ingredients of the raw material composition, it is easy to form a curable adhesive layer capable of obtaining a cured product having excellent adhesion after a high-temperature, high-humidity test.

When the raw material composition used in one aspect of the present invention contains a silane coupling agent (F), the content of the silane coupling agent (F) (when two or more silane coupling agents are included) is 100 parts by mass of the component (A). In the case of the mixture (F), the total amount of these silane coupling agents (F) is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, further preferably 0.1 parts by mass or more, and even more preferably 0.15 parts by mass or more, And it is preferably 3 parts by mass or less, more preferably 1 part by mass or less, still more preferably 0.7 parts by mass or less, still more preferably 0.5 parts by mass or less.

[(E) component: cationic polymerization initiator] The raw material composition may contain a cationic polymerization initiator as (E) component. When the curing reaction (I) or the curing reaction (II) is a cationic polymerization reaction, these curing reactions can be efficiently performed by adding a cationic polymerization initiator to the raw material composition. The cationic polymerization initiators can be used alone or in combination of two or more. As a cationic polymerization initiator (E), a thermal cationic polymerization initiator or a photocationic polymerization initiator is mentioned, Preferably it is a thermal cationic polymerization initiator which can polymerize by a simple process.

Thermal cationic polymerization initiators are compounds that generate cationic species that initiate polymerization by heating. Examples of the thermal cationic polymerization initiator include periumium salts, quaternary ammonium salts, phosphonium salts, diazonium salts, and iodonium salts.

Examples of columium salts include: triphenylcolumbitium tetrafluoroborate, triphenylcolumbitium hexafluoroantimonate, triphenylcolumbitium hexafluoroarsenate, tris(4-methoxyphenyl)columbitium hexafluoroarsenate acid salt, diphenyl(4-phenylthiophenyl) percilium hexafluoroarsenate, etc.

Examples of quaternary ammonium salts include: tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium bisulfate, tetraethylammonium tetrafluoroborate, tetraethylammonium p-toluene Sulfonate, N,N-Dimethyl-N-benzylanilinium hexafluoroantimonate, N,N-Dimethyl-N-benzylanilinium tetrafluoroborate, N,N-Dimethyl-N-benzylanilinium tetrafluoroborate -N-benzylpyridinium hexafluoroantimonate, N,N-diethyl-N-benzyl trifluoromethanesulfonate, N,N-dimethyl-N-(4-methoxybenzyl ) pyridinium hexafluoroantimonate, N,N-diethyl-N-(4-methoxybenzyl) toluidine hexafluoroantimonate, etc.

Examples of the phosphonium salt include ethyltriphenylphosphonium hexafluoroantimonate, tetrabutylphosphonium hexafluoroantimonate, and the like.

Examples of the iodine salt include: diphenyliodonium hexafluoroarsenate, bis(4-chlorophenyl)iodonium hexafluoroarsenate, bis(4-bromophenyl)iodonium hexafluoroarsenate, phenyl( 4-methoxyphenyl)iodonium hexafluoroarsenate, etc.

When the raw material composition contains the cationic polymerization initiator (E), the content of the cationic polymerization initiator (E) relative to the total of 100 parts by mass of the (C) component and (D) component which are cationic polymerizable compounds (When two or more (E) components are included, the total amount of these (E) components) is preferably at least 0.01 parts by mass, more preferably at least 0.05 parts by mass, still more preferably at least 0.1 parts by mass, still more preferably at least 0.1 parts by mass 0.2 mass parts or more, Preferably it is 6 mass parts or less, More preferably, it is 5 mass parts or less, More preferably, it is 4 mass parts or less. When content of a cationic polymerization initiator is 0.01 mass part or more, it becomes easy to prevent reactivity fall. When content of a cationic polymerization initiator is 6 mass parts or less, corrosion of an adherend can be suppressed easily.

[solvent] The raw material composition may also contain a solvent and be in the form of a solution. Examples of solvents include aromatic hydrocarbon solvents such as benzene and toluene; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; n-pentane , n-hexane, n-heptane and other aliphatic hydrocarbon solvents; cyclopentane, cyclohexane, methylcyclohexane and other alicyclic hydrocarbon solvents, etc. These solvents may be used alone or in combination of two or more. When the raw material composition contains a solvent, the content of the solvent can be appropriately determined in consideration of applicability and the like.

[other ingredients] The raw material composition may contain components (other components) other than those described so far within the range that does not interfere with the effects of the present invention. Examples of other components include additives such as ultraviolet absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, pigments, extenders, and softeners. These components may be used alone or in combination of two or more. When the raw material composition contains these additives, the content of the additives can be appropriately determined according to the purpose.

[Manufacturing method of raw material composition] The raw material composition can be prepared by appropriately mixing and stirring the binder resin (A) and the crosslinking agent (B) and other optional components according to a usual method.

[hardening adhesive layer] The curable adhesive layer constituting the adhesive sheet of the present invention is a layer formed using the aforementioned raw material composition.

For example, a curable adhesive layer can be formed by coating the raw material composition on a process sheet or a protective sheet, drying the obtained coating film, and then performing the aforementioned hardening reaction (I).

Examples of methods for coating the raw material composition include spin coating, spray coating, bar coating, blade coating, roll coating, knife coating, die coating, and gravure coating.

As a method of drying a coating film, conventionally known drying methods, such as hot-air drying, hot-roll drying, and infrared-ray irradiation, are mentioned. The conditions for drying the coating film are, for example, 80° C. to 150° C. and 30 seconds to 5 minutes.

When the curing reaction (I) is a reaction initiated by heat, the drying treatment of the coating film and the curing reaction (I) may be performed simultaneously. For example, the reactive functional group in the binder resin (A) is a carboxyl group or carboxylic anhydride group, and the crosslinking agent (B) is an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, or a metal chelate-based crosslinking agent In the case of etc., by heating the coating film to about 100° C., the drying treatment and the curing reaction (I) can be performed simultaneously, and a curable adhesive layer can be formed efficiently.

The thickness of the curable adhesive layer is usually at least 1 μm, preferably at least 5 μm. Furthermore, the thickness of the curable adhesive layer is usually not more than 50 μm, preferably not more than 25 μm. When the thickness of the curable adhesive layer is 1 μm or more, it is easy to obtain adhesiveness that is easy to follow the level difference. If the thickness of the curable adhesive layer is 50 μm or less, the rigidity will not be too high and flexibility will be easily obtained.

The gel fraction of the curable adhesive layer is at least 10% by mass, preferably at least 15% by mass, more preferably at least 20% by mass, particularly preferably at least 25% by mass. The gel fraction of the curable adhesive layer is usually 70% by mass or less, preferably 60% by mass or less, and more preferably less than 50% by mass. The curable adhesive layer having a gel fraction of 10% by mass or more has a sufficiently cross-linked structure as the curable adhesive layer. Therefore, even if such a curable adhesive layer is subjected to heat treatment such as hot pressing, the adhesive components will not ooze out in large quantities, and contamination of the surroundings can be suppressed. When the gel fraction of the curable adhesive layer is 70% by mass or less, it is easy to form a curable adhesive layer excellent in curability or adhesion to an adherend. The gel fraction of the curable adhesive layer can be calculated by performing an experiment of immersing the curable adhesive layer in toluene at 23° C. for 168 hours as described in the examples.

As a curable adhesive layer, it is preferable to have a low dielectric property. A curable adhesive layer having low dielectric properties can be preferably used as a forming material of an adhesive member, a protective member, an insulating member, etc. in an electronic component.

The dielectric tangent of the curable adhesive layer at 23°C and a frequency of 1 GHz is preferably less than 0.0050, more preferably 0.0030 or less, more preferably 0.0020 or less, still more preferably 0.0015 or less, still more preferably 0.0012 or less, still more preferably 0.0010 or less, preferably 0.0008 or less. The lower limit of the dielectric tangent under this condition does not particularly exist, and is usually 0.0001 or more.

The relative dielectric constant of the curable adhesive layer at 23° C. and a frequency of 1 GHz is preferably 3.00 or less, more preferably 2.75 or less, and still more preferably 2.50 or less. The lower limit of the relative permittivity under this condition does not particularly exist, and is usually 2.00 or more.

The curable adhesive layer is a curable layer. As described above, as the raw material composition of the curable adhesive layer, there is a raw material composition having only the hardening reaction (I) as the hardening reaction [raw material composition (α)], or a hardening reaction (I) and the hardening reaction (II) Raw material composition [raw material composition (β)] as a hardening reaction. The "curability" of the curable adhesive layer formed using the raw material composition (α) is due to the reaction between the unreacted adhesive resin (A) and the crosslinking agent (B) in the curable adhesive layer (that is, hardening reaction (I)). On the other hand, the "curability" of the curable adhesive layer formed using the raw material composition (β) is usually caused by both the hardening reaction (I) and the hardening reaction (II), or only by the hardening reaction (II ) caused by.

The curing conditions of the curable adhesive layer can be appropriately determined according to the curable components contained in the curable adhesive layer. For example, when the curable adhesive layer is a thermosetting adhesive layer containing the aforementioned (C) component and (D) component as curable components, the curable adhesive layer can be heated with high efficiency. The hardening reaction of the hardening adhesive layer is carried out in a timely manner. The heating temperature of the curable adhesive layer is usually above 140°C, preferably 150°C to 180°C. The heating time of the curable adhesive layer is usually 0.5 hour to 3 hours, preferably 1 hour to 2 hours.

In the hardened product formed by curing the curable adhesive layer, there are usually more cross-linked structures than in the curable adhesive layer. Therefore, the gel fraction of the cured product generally takes a larger value than the gel fraction of the curable adhesive layer. When the cured product of the curable adhesive layer functions as an adhesive member, a protective member, an insulating member, etc., it is preferable that the cured product has fully undergone a curing reaction. The gel fraction of the cured product in such a state is preferably at least 50% by mass, more preferably at least 55% by mass. In addition, the upper limit of the gel fraction of the cured product in a state where the curing reaction has sufficiently progressed is not particularly present, but is usually 95% by mass or less, preferably 90% by mass or less. The gel fraction of the cured product can be obtained by the same method as the calculation method of the gel fraction of the curable adhesive layer.

In terms of being suitable as a forming material for an adhesive member, a protective member, an insulating member, etc., as a curable adhesive layer, it is preferable to form a gel fraction of 50% by mass after curing at 160°C for 1 hour Hardened products above.

[continuing film] The adhesive sheet of the present invention has the aforementioned curable adhesive layer. The adhesive sheet of the present invention may have protective sheets on one side or both sides for protection during storage or transportation.

The adhesive sheet of the present invention is suitable as an adhesive sheet for electronic components. Examples of electronic components include communication devices such as smartphones and tablet terminals. For example, the curable adhesive layer constituting the adhesive sheet of the present invention can be used to bond various components in an electronic component, or to form a protective material or an insulating material for a circuit in an electronic component.

The adhesive sheet of the present invention is suitably used as an adhesive sheet for coverlay films. The coverlay film is, for example, a laminated film used to protect the surface of a flexible printed wiring board, and generally has an insulating resin layer and an adhesive layer. For example, a coverlay film can be produced by thermocompression-bonding the curable adhesive layer constituting the adhesive sheet of the present invention and the insulating resin film. [Example]

Hereinafter, examples are given and the present invention will be described in more detail. However, the present invention is not limited to the following examples at all.

[Compounds used in Examples or Comparative Examples] Binder resin (A1): maleic anhydride modified α-olefin polymer [manufactured by Mitsui Chemicals Co., Ltd., trade name: Unistole H-200, number average molecular weight: 47,000] · Isocyanate-based crosslinking agent (B1): 1,3,5-tris(5-isocyanatopentyl)-1,3,5-triazine-2,4,6-trione [manufactured by Mitsui Chemicals Co., Ltd., Trade name: Stabio D-370N, molecular weight: 462] · Epoxy-based crosslinking agent (B2): 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane [manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: TETRAD-C, molecular weight :362] ・Metal chelate-based crosslinking agent (B3): Tris(acetylacetonate)aluminum [manufactured by Soken Chemical Co., Ltd., trade name: M-5A, molecular weight: 324] · Hardening compound (C1): a compound having an isocyanurate skeleton and two allyl groups [manufactured by Shikoku Chemical Industry Co., Ltd., trade name: L-DAIC] · Polyphenylene ether resin (D1): vinylbenzyl modified polyphenylene ether [manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: OPE-2St 1200, number average molecular weight: 1200] Cationic polymerization initiator (E1): Thermal cationic polymerization initiator [manufactured by Sanshin Chemical Industry Co., Ltd., trade name: San-aid SI-B3] · Silane coupling agent (F1): 8-glycidyloxyoctyltrimethoxysilane [manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM4803]

[Example 1] 100 parts by mass of binder resin (A1), 0.5 parts by mass of isocyanate crosslinking agent (B1), 12.5 parts by mass of hardening compound (C1), 25 parts by mass of polyphenylene ether resin (D1), cationic polymerization initiator (E1 ) and 0.12 parts by mass of the silane coupling agent (F1) were dissolved in toluene to prepare a raw material composition. On the release-treated surface of the release sheet (the first release sheet, manufactured by Lintec Co., Ltd., trade name: SP-PET752150), the obtained raw material composition was applied to form a coating film, and the obtained coating film was placed on Dry at 100°C for 2 minutes to form a curable adhesive layer with a thickness of 15 μm. On the exposed surface of the curable adhesive layer, the release-treated surface of another release sheet (second release sheet, manufactured by Lintec Corporation, trade name: SP-PET381130) was attached to obtain an adhesive sheet.

[Example 2 to Example 5, Comparative Example 1] Except having changed the compounding quantity or kind of a component into Table 1, the raw material composition was prepared similarly to Example 1, and the adhesive sheet was obtained.

[Gel Fraction of Hardening Adhesive Layer] After cutting the adhesive sheet obtained in the example or comparative example into a size of 80 mm in length and 80 mm in width, both peeling sheets were peeled off to obtain a curable adhesive layer. Next, the obtained curable adhesive layer was wrapped in a polyester mesh (mesh size 200) whose mass had been measured in advance to prepare a test sample. After the test sample was left to stand for 24 hours in an environment with a temperature of 23°C and a relative humidity of 50%, the mass of the test sample was weighed with a precision balance. The mass (M1) of the curable adhesive layer before immersion was calculated based on the obtained measured value. Next, the test sample was immersed in 0.2 L of toluene at room temperature (23° C.) for 168 hours. After dipping, take out the test sample, dry the test sample in an oven at 100°C for 2 hours, and then let it stand for 24 hours in an environment with a temperature of 23°C and a relative humidity of 50%. Weigh the mass of the dried test sample with a precision balance. The mass (M2) of the curable adhesive layer after dipping and drying was calculated based on the obtained measured value. The gel fraction of the curable adhesive layer was calculated from the value of M1 and the value of M2 from the following formula. ·Gel fraction (mass %)=(M2/M1)×100.

[Gel fraction of cured product] The adhesive sheet obtained in the example or comparative example was cut into a size of 80 mm in length x 80 mm in width, and heated at 160° C. for 1 hour in an oven. Using the cured product obtained by peeling off the release sheet, the gel fraction of the cured product was calculated in the same manner as above.

[Evaluation of exudation of ingredients] Peel off one piece of the peeling sheet of the adhesive sheet obtained in the examples or comparative examples, and use a heat laminator to bond the exposed curable adhesive layer with the polyimide film (Toray-Dupont) at 100°C. ) company, Kapton, thickness 25μm) crimping to obtain a laminate with a structure of release sheet/hardening adhesive layer/polyimide film. Then, the release sheet of the laminate was peeled off, and the exposed curable adhesive layer was bonded to copper foil at 100°C using a thermal laminator to obtain copper foil/hardenable adhesive layer/polyimide film The laminate of the structure. Furthermore, the copper foil has a wider area than the other two layers, so when the adhesive component of the curable adhesive layer seeps out, it will adhere to the copper foil. This laminate was subjected to hot press treatment at 171° C. and 1.38 MPa for 20 minutes. After cooling, the length of the adhesive component that oozes out most from the adhesive layer (cured product) in plan view was measured using a digital microscope [the length of the portion indicated by X in FIG. 1 (μm)]. The results are shown in Table 1. In addition, FIG. 1 is a schematic plan view of the laminated body used for evaluating the exudation of an adhesive agent component in an Example, and it top-viewed after heat-pressing. As shown in Fig. 1, under the influence of hot pressing treatment, part of the adhesive layer (cured product) sandwiched between the copper foil 1 and the polyimide film 3 of the above-mentioned laminate oozes out, and the oozing adhesive component 2 May be attached to copper foil 1. At this time, as shown in FIG. 1 , the maximum value X of the distance X between the adhesive agent component 2 and the polyimide film 3 that exuded in plan view was set as "the exudation length of the adhesive agent component", and described in Table 1.

[relative permittivity, dielectric tangent] The curable adhesive layer of the adhesive sheet obtained in the example or comparative example was laminated to a thickness of approximately 1mm, and then welded at 100°C using a thermal laminator to obtain a release sheet/approximately 1mm A laminate with a hardening adhesive layer/release sheet structure. The release sheets on both sides of the laminate were peeled off to obtain a measurement sample. The relative permittivity and dielectric tangent at 23° C. and 1 GHz were measured for the obtained measurement sample using an RF impedance-material analyzer (manufactured by Keysight Technologies, E4991A). In addition, in this specification, the so-called high-frequency region refers to the region of 300 MHz to 300 GHz, but in this embodiment, 1 GHz is used as an example of the high-frequency region. The results are shown in Table 1.

[Table 1]

The curable adhesive layers of the adhesive sheets obtained in Examples 1 to 5 all had high gel fractions. Therefore, even if these curable adhesive layers were subjected to hot pressing at 171°C, 1.38 MPa, and 20 minutes, the amount of oozing out of the adhesive components was small. On the other hand, the curable adhesive layer of the adhesive sheet of Comparative Example 1 had a low value of the gel fraction. Therefore, if the curable adhesive layer is subjected to hot pressing under the same conditions, the amount of exudation of the adhesive components will increase. Moreover, the curable adhesive layer of the adhesive sheet obtained in Examples 1 to 5 has excellent low dielectric properties.

1: copper foil 2: Exuding adhesive ingredients 3: Polyimide film

[ Fig. 1 ] is a schematic diagram (plan view) of a part of a laminate used for evaluating the exudation of adhesive components. [ Fig. 2 ] is a schematic view showing a section A-A of Fig. 1 .

Claims (14)

An adhesive sheet with a hardening adhesive layer; The raw material composition of the aforementioned curable adhesive layer contains the following (A) component and (B) component, and relative to the total amount of active ingredients of the aforementioned raw material composition, it contains 0.1% by mass or more of the (B) component; The curable adhesive layer has a gel fraction of 10% by mass or more; (A) Component: a binder resin with reactive functional groups; Component (B): A crosslinking agent capable of reacting with the aforementioned component (A). The adhesive sheet as described in claim 1, wherein the aforementioned component (A) is a polyolefin-based resin. The adhesive sheet as described in claim 1 or 2, wherein the aforementioned component (A) is an acid-modified resin. The adhesive sheet according to any one of claims 1 to 3, wherein the aforementioned component (B) is a compound having an isocyanurate skeleton. The adhesive sheet according to any one of claims 1 to 4, wherein the aforementioned component (B) is a compound having two or more isocyanate groups. The adhesive sheet as described in any one of Claims 1 to 5, wherein the curable adhesive layer is a layer formed of a raw material composition further containing the following (C) component; Component (C): A non-aromatic hardening compound that is liquid at 25°C. The adhesive sheet as described in Claim 6, wherein the aforementioned component (C) is a compound having two or more hydrocarbon groups having double bonds at the ends. The adhesive sheet according to any one of Claims 1 to 7, wherein the curable adhesive layer is a layer formed of a raw material composition further containing the following (D) component; (D) Component: polyphenylene ether resin with reactive functional groups. The adhesive sheet according to any one of Claims 1 to 8, wherein the curable adhesive layer is a layer formed of a raw material composition further containing the following (E) component; (E) component: a cationic polymerization initiator. The adhesive sheet according to any one of claims 1 to 9, wherein the dielectric tangent of the curable adhesive layer at 23°C and a frequency of 1 GHz is less than 0.005. The adhesive sheet according to any one of Claims 1 to 10, wherein the relative dielectric constant of the curable adhesive layer at 23°C and a frequency of 1 GHz is 3.00 or less. The adhesive sheet according to any one of claims 1 to 11, wherein the curable adhesive layer is cured at 160°C for 1 hour to form a hardened product with a gel fraction of 50% by mass or more. The adhesive sheet described in any one of claims 1 to 12 is used for electronic components. The adhesive sheet described in any one of Claims 1 to 12 is used for a cover film.

Images