Adhesive composition, adhesive, adhesive layer, adhesive sheet, laminate and adhesive composition

Abstract

To provide a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive having a low dielectric constant, a low dielectric loss tangent and excellent pressure-sensitive adhesive properties.SOLUTION: The pressure-sensitive adhesive composition contains a polyester resin (A) having a structural moiety derived from a polycarboxylic acid (a1) and a structural moiety derived from a polyhydric alcohol (a2). The content of a structural moiety derived from an aromatic polycarboxylic acid (a1-1) is 20 mol% or more in the structural moiety derived from the polycarboxylic acid (a1). The content of a structural moiety derived from a polydiene diol and / or a hydrogenated polydiene diol (a2-1) is 20 mol% or more in the structural moiety derived from the polyhydric alcohol (a2).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an adhesive composition, an adhesive obtained by crosslinking the adhesive composition, an adhesive layer, an adhesive sheet provided with the adhesive layer, a laminate, and an adhesive composition. More specifically, the present invention relates to an adhesive composition having a low dielectric constant and a low dielectric tangent and excellent adhesive physical properties, and an adhesive obtained by crosslinking the adhesive composition, an adhesive layer, an adhesive sheet provided with the adhesive layer, a laminate, and an adhesive composition.

Background Art

[0002] Conventionally, polyester resins have been used in a wide range of applications such as films, PET bottles, fibers, toners, electrical components, adhesives, and adhesives because they are excellent in heat resistance, chemical resistance, durability, and mechanical strength. Further, since polyester resins have high polarity due to their polymer structure, they are known to exhibit excellent adhesiveness to polar polymers such as polyester, polyvinyl chloride, polyimide, and epoxy resins, and metal materials such as copper and aluminum.

[0003] For example, Patent Document 1 aims to obtain a thermosetting adhesive sheet excellent in dimensional stability during curing and excellent in adhesiveness, heat resistance, flexibility, electrical insulation, low dielectric constant, and low dielectric tangent. A thermosetting composition containing a resin (for example, a polyester resin) in which the total amount of a reactive functional group capable of reacting with at least one of an organometallic compound or an epoxy group-containing compound and a functional group having a heteroatom other than halogen is 0.01 mmol / g or more and 9 mmol / g or less, an organometallic compound, and a polyfunctional or higher epoxy group-containing compound has been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, with the increasing frequency of transmitted signals, low dielectric properties, particularly low dielectric loss tangent, have become necessary for adhesives used for fixing and bonding devices. For example, low dielectric properties are required for adhesive layers used in bonding transparent antenna films and radio wave reflective films for millimeter-wave and similar high-frequency radio waves. However, the technology disclosed in Patent Document 1 reduces the ester bond concentration to achieve low dielectric constant, low dielectric loss tangent, and low water absorption. However, the demand for low dielectric properties in recent years is very high, and simply reducing the ester bond concentration is insufficient, requiring further improvements.

[0006] Therefore, against this background, the present invention aims to provide an adhesive composition having a low dielectric constant and low dielectric loss tangent and excellent adhesive properties, an adhesive obtained by crosslinking the above adhesive composition, an adhesive layer, an adhesive sheet comprising the above adhesive layer, a laminate, and an adhesive composition.

[0007] While acrylic resin-based adhesives are widely used as adhesives, and acrylic adhesives aiming for low dielectric loss tangents are also known, these acrylic adhesives have the problem of having very low adhesive strength due to their design. Furthermore, while adhesive strength can be improved by adding a large amount of tackifier, this has the problem of degrading transparency, heat resistance, and durability, making it difficult to achieve both low dielectric loss tangent and high adhesive properties simultaneously with acrylic adhesives. The present invention aims to provide polyester-based adhesives and bonding agents that are superior to acrylic-based adhesives in that they can achieve a high level of both low dielectric properties and adhesive properties. [Means for solving the problem]

[0008] However, in view of these circumstances, the inventors conducted extensive research and found that using an adhesive composition made of a polyester resin having a specific structure would satisfy the objectives of the present invention, thus completing the present invention.

[0009] In other words, the gist of the present invention is as follows: [1] to

[12] . [1] An adhesive composition containing a polyester resin (A) having structural sites derived from polycarboxylic acids (a1) and structural sites derived from polyhydric alcohols (a2), In the structural site derived from the above polycarboxylic acid (a1), the content of the structural site derived from aromatic polycarboxylic acid (a1-1) is 20 mol% or more. An adhesive composition in which the structural site derived from the above polyhydric alcohol (a2) contains 20 mol% or more of a structural site derived from polydienediol and / or hydrogenated polydienediol (a2-1). [2] The adhesive composition according to [1], wherein the total amount of structural sites derived from the above aromatic polycarboxylic acids (a1-1) and structural sites derived from polydienediol and / or hydrogenated polydienediol (a2-1) in the polysyl resin (A) is 90% by weight or more. [3] The adhesive composition according to [1] or [2], wherein the number average molecular weight of the polydienediol and / or hydrogenated polydienediol (a2-1) is 500 to 10000. [4] The adhesive composition according to any one of [1] to [3], wherein the polydienediol and / or hydrogenated polydienediol (a2-1) is a polydienediol formed from a conjugated diene having 4 to 9 carbon atoms and / or a hydrogenated polydienediol formed from a conjugated diene having 4 to 9 carbon atoms. [5] The adhesive composition according to any one of [1] to [4], wherein the dielectric loss tangent of the polyester resin (A) at a frequency of 10 GHz under a temperature of 23°C and a relative humidity of 50% RH is 0.01 or less. [6] The adhesive composition according to any one of [1] to [5], wherein the acid value of the polyester resin (A) is 10 mg KOH / g or less. [7] The adhesive composition according to any one of [1] to [6] further containing a crosslinking agent (B). [8] An adhesive obtained by crosslinking any of the adhesive compositions described in [1] to [7]. [9] A crosslinked adhesive layer comprising an adhesive composition containing a polyester resin (A) having structural sites derived from polycarboxylic acids (a1) and structural sites derived from polyhydric alcohols (a2), and a crosslinking agent (B), In the structural site derived from the above polycarboxylic acid (a1), the content of the structural site derived from aromatic polycarboxylic acid (a1-1) is 20 mol% or more. In the structural site derived from the above polyhydric alcohols (a2), the content of the structural site derived from polydienediol and / or hydrogenated polydienediol (a2-1) is 20 mol% or more. An adhesive layer having a dielectric loss tangent of 0.01 or less at a frequency of 10 GHz under conditions of 23°C and 50% RH relative humidity. An adhesive sheet comprising the adhesive layer described in

[10] [9], a release sheet on one side of the adhesive layer, and a substrate on the other side, wherein the dielectric loss tangent of the substrate at a frequency of 10 GHz under conditions of a temperature of 23°C and a relative humidity of 50%RH is 0.01 or less. A laminate comprising an adhesive layer as described in

[11] [9] and a substrate on at least one surface of the adhesive layer, wherein the dielectric loss tangent of the substrate at a frequency of 10 GHz under conditions of a temperature of 23°C and a relative humidity of 50%RH is 0.01 or less.

[12] An adhesive composition containing a polyester resin (A) having structural sites derived from polycarboxylic acids (a1) and structural sites derived from polyhydric alcohols (a2), In the structural site derived from the above polycarboxylic acid (a1), the content of the structural site derived from aromatic polycarboxylic acid (a1-1) is 20 mol% or more. An adhesive composition characterized in that, in the structural site derived from the above polyhydric alcohol (a2), the content of the structural site derived from polydienediol and / or hydrogenated polydienediol (a2-1) is 20 mol% or more.

[0010] As described in Patent Document 1 above, typically the water absorption rate, dielectric constant, and dielectric loss tangent are reduced. To achieve this, one might consider using large amounts of polycarboxylic acids or polyhydric alcohols with long-chain alkyl groups to lower the ester bond concentration. However, this would reduce long-term durability in humid and hot environments. Furthermore, simply lowering the ester bond concentration does not make it possible to obtain even lower dielectric properties. The inventors of the present invention have completed the present invention by finding that a polyester resin has a low dielectric constant, a low dielectric loss tangent, and excellent adhesive properties, by adjusting the composition of the monomers that make up the polyester resin. [Effects of the Invention]

[0011] The adhesive composition of the present invention has a low dielectric constant and low dielectric loss tangent, and further exhibits excellent tackiness, making it effective as an adhesive for use in electronic devices that transmit and receive high-frequency signals. Furthermore, the adhesive layer of the present invention has a low dielectric constant and low dielectric loss tangent, and also excellent adhesive properties, making it effective in adhesive sheets and laminates used in electronic devices that transmit and receive high-frequency signals. [Modes for carrying out the invention]

[0012] The configuration of the present invention will be described in detail below, but these are merely examples of preferred embodiments. In this invention, the term "class" appended to a compound name encompasses not only the compound itself but also its derivatives. For example, the term "carboxylic acids" includes not only carboxylic acids but also carboxylic acid derivatives such as carboxylic acid salts, carboxylic acid anhydrides, carboxylic acid halides, and carboxylic acid esters having approximately 1 to 8 carbon atoms. Furthermore, in this invention, "y and / or z (where y and z are any configuration or component)" means one of three possible combinations: y only, z only, or y and z.

[0013] The adhesive sheet in this specification is obtained by laminating a release film on at least one surface of an adhesive and a release film or a base film on the other surface, and refers to a sheet that is attached to an adherend by peeling off the release film. Such a release film may be one obtained by subjecting the back surface of the base film to a release treatment. Also, the adhesive sheet in this specification refers to a sheet obtained by applying an adhesive composition to a base film and directly attaching the adhesive composition to an adherend without laminating a release film.

[0014] The adhesive composition of the present invention or the adhesive composition of the present invention (hereinafter referred to as "the present composition") contains a polyester resin (A) containing a structural site derived from polycarboxylic acids (a1) and a structural site derived from polyhydric alcohols (a2). First, the polyester resin (A) will be described.

[0015] <Polyester resin (A)> The polyester resin (A) contains in its molecule a structural site derived from polycarboxylic acids (a1) and a structural site derived from polyhydric alcohols (a2). In the structural site derived from the polycarboxylic acids (a1), the content of the structural site derived from aromatic polycarboxylic acids (a1-1) is 20 mol% or more. In the structural site derived from the polyhydric alcohols (a2), the content of the structural site derived from polydiene diol and / or hydrogenated polydiene diol (a2-1) [hereinafter sometimes referred to as "polydiene diols (a2-1)"] is 20 mol% or more. Further, the polyester resin (A) is preferably obtained by esterifying polycarboxylic acids (a1) and polyhydric alcohols (a2).

[0016] Generally, it is known that a polyester resin containing a structural site derived from polybutadiene can be used as an adhesive, and by containing a polybutadiene structure, the adhesion to polyolefins such as polypropylene is improved. On the other hand, in the present invention, it has been found that by using a polyester resin (A) containing a specific amount or more of structural sites derived from aromatic polycarboxylic acids (a1-1) and a specific amount or more of structural sites derived from polydienediols (a2-1), the dielectric properties are uniquely improved (dielectric constant and dielectric loss tangent are reduced). Normally, making a resin hydrophobic improves its dielectric properties. However, in this invention, we have found that, surprisingly, by introducing a specific amount or more of structural sites derived from aromatic polycarboxylic acids (a1-1) or polydienediols (a2-1), which are more hydrophilic than alkyl chains, the dielectric properties of polyester resins, which are usually considered to have poor dielectric properties (high dielectric constant and dielectric loss tangent), can be significantly improved. Although the reason is not clear, it is thought that the introduction of structural sites derived from aromatic polycarboxylic acids (a1-1) in amounts exceeding a certain level suppresses the mobility of polymer molecules, and furthermore, the inclusion of a large amount of structural sites derived from polydienediols (a2-1) reduces the polarity by decreasing the highly polar ester bonds. It is presumed that the dielectric properties are improved by the combination of this suppression of molecular motion and reduction of polarity.

[0017] [Structural site derived from polycarboxylic acids (a1)] Examples of structural sites derived from polycarboxylic acids (a1) include structural sites derived from aromatic polycarboxylic acids (a1-1), structural sites derived from alicyclic polycarboxylic acids, and structural sites derived from aliphatic polycarboxylic acids. One or more structural sites derived from polycarboxylic acids (a1) may be included.

[0018] The structural moieties derived from polycarboxylic acids (a1) contain structural moieties derived from aromatic polycarboxylic acids (a1-1) from the viewpoint of low dielectric properties. Aromatic polycarboxylic acids (a1-1) that constitute the structural moieties derived from aromatic polycarboxylic acids (a1-1) include, for example, aromatic dicarboxylic acids such as terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, orthophthalic acid, naphthalenedicarboxylic acid, dimethyl naphthalenedicarboxylic acid, biphenyldicarboxylic acid, trimellitic acid, trimesic acid, ethylene glycol bis(anhydrotrimellitate), glycerol tris( Examples include trivalent or higher aromatic carboxylic acids such as anhydrotrimellitates, pyromellitic acids, oxydiphthalic acids, 3,3',4,4'-benzophenonetetracarboxylic acids, 3,3',4,4'-diphenyltetracarboxylic acids, 3,3',4,4'-diphenylsulfonetetracarboxylic acids, 4,4'-(hexafluoroisopropylidene)diphthalic acids, and 2,2'-bis[(dicarboxyphenoxy)phenyl]propanes.

[0019] Among these, it is preferable to use aromatic dicarboxylic acids, that is, the polyester resin (A) has structural units derived from aromatic dicarboxylic acids, and it is particularly preferable that it has structural parts derived from terephthalic acids, structural parts derived from isophthalic acids, and structural parts derived from naphthalenedicarboxylic acids, and it is even more preferable from the viewpoint of adhesive properties and low dielectric properties that it has structural parts derived from isophthalic acids. Furthermore, in terms of reactivity, it is preferable to use esterified versions of these lower alkyl groups, and specifically, dimethyl terephthalic acid, dimethyl isophthalic acid, and dimethyl naphthalenedicarboxylic acid are preferred.

[0020] The content of structural sites derived from aromatic polycarboxylic acids (a1-1) in the structural sites derived from polycarboxylic acids (a1) is 20 mol% or more, more preferably 50 mol% or more, even more preferably 70 mol% or more, particularly preferably 82 mol% or more, especially preferably 90 mol% or more, and most preferably 100 mol%. If the content of structural sites derived from aromatic polycarboxylic acids (a1-1) is too low, the dielectric properties will be poor, and it will be particularly difficult to obtain a low dielectric loss tangent. Furthermore, "poor dielectric properties" means that the dielectric constant and dielectric loss tangent do not decrease, or that their values ​​increase.

[0021] The content (mol%) of structural sites derived from aromatic polycarboxylic acids (a1-1) relative to the total structural sites derived from polycarboxylic acids (a1) can be calculated using the following formula 1. [Formula 1] Content of structural sites derived from aromatic polycarboxylic acids (a1-1) (mol%) = (Structural sites derived from aromatic polycarboxylic acids (a1-1) (moles) / Structural sites derived from polycarboxylic acids (a1) (moles)) × 100

[0022] The content of structural sites derived from aromatic polycarboxylic acids (a1-1) in the total polyester resin (A) is preferably 1 to 30% by weight, more preferably 2 to 20% by weight, and even more preferably 3 to 10% by weight. If the content of structural sites derived from aromatic polycarboxylic acids (a1-1) is too low, the dielectric properties tend to be poor, and in particular, it tends to be difficult to obtain a low dielectric loss tangent, while if it is too high, the tack properties tend to be insufficient.

[0023] Furthermore, when imparting an acid value to a polyester resin (A), it is preferable from the viewpoint of adhesiveness to include a structural site derived from polycarboxylic acids (a1) having 0 or 1 acid anhydride group and a valency of 3 or higher. The valency of the carboxyl group in the above-mentioned structural site derived from polycarboxylic acids having 0 or 1 acid anhydride group and a valency of 3 or higher is preferably 3 to 6, and more preferably 3 to 4. Examples of polycarboxylic acids having 0 or 1 acid anhydride group and a valency of 3 or higher that constitute such a structural site derived from polycarboxylic acids having 0 or 1 acid anhydride group include, for example, the above-mentioned aromatic polycarboxylic acids having 0 or 1 acid anhydride group. Examples include trimellitic anhydride, trimellitic acids, trimesic acids, etc. Examples of other polycarboxylic acids having 0 or 1 acid anhydride group and a valency of 3 or higher include, for example, hydrogenated trimellitic anhydride. Among these, those with 1 acid anhydride group are preferred, and structural sites derived from trimellitic anhydride are particularly preferred.

[0024] Examples of alicyclic polycarboxylic acids that constitute the structural sites derived from the above-mentioned alicyclic polycarboxylic acids include 1,4-cyclohexanedicarboxylic acids, 1,3-cyclohexanedicarboxylic acids, and 1,2-cyclohexanedicarboxylic acids.

[0025] The structural sites derived from the above aliphatic polycarboxylic acids are composed of aliphatic polycarboxylic acids. Examples include succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanediic acid.

[0026] When the polyester resin (A) contains structural sites derived from alicyclic polycarboxylic acids and structural sites derived from aliphatic polycarboxylic acids, the total content of structural sites derived from polycarboxylic acids (a1) is preferably 30 mol% or less, more preferably 18 mol% or less, and particularly preferably 10 mol% or less.

[0027] The polyester resin (A) may contain structural units derived from aromatic dicarboxylic acids having sulfonic acid groups, such as structural units derived from sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acids, and 5(4-sulfophenoxy)isophthalic acid, as well as structural units derived from aromatic dicarboxylic acid salts having sulfonic acid bases, such as metal salts and ammonium salts thereof. However, from the viewpoint of the hygroscopicity of the polyester resin (A) and the compatibility of the resin, the content of structural units derived from polycarboxylic acids (a1) relative to the total is preferably 10 mol% or less, more preferably 5 mol% or less, particularly preferably 3 mol% or less, even more preferably 1 mol% or less, and most preferably 0 mol%.

[0028] [Structural parts derived from polyhydric alcohols (a2)] Examples of structural sites derived from polyhydric alcohols (a2) include structural sites derived from polydiene diols (a2-1), structural sites derived from dimer diols, structural sites derived from bisphenol skeleton-containing monomers, structural sites derived from aliphatic polyhydric alcohols, structural sites derived from alicyclic polyhydric alcohols, and structural sites derived from aromatic polyhydric alcohols. The structural sites derived from polyhydric alcohols (a2) may be present individually or in combination of two or more types.

[0029] In this invention, the structural unit derived from polydienediols (a2-1) is included as a structural site derived from polyhydric alcohols (a2).

[0030] The polydiene diols (a2-1) that constitute the structural site derived from the above-mentioned polydiene diols (a2-1) are preferably polydiene diols formed from conjugated dienes having 4 to 9 carbon atoms and / or hydrogenated polydiene diols formed from conjugated dienes having 4 to 9 carbon atoms, due to their excellent dielectric properties. Examples include polybutadiene diols, polyisoprendiols, polyhexadiene diols, etc., with hydroxyl groups at both ends, and hydrogenated versions thereof. These may be used individually or in combination of two or more. Among these, hydrogenated versions are preferred from the viewpoint of suppressing gelation during the production of polyester resin (A), and hydrogenated polybutadiene diols are preferred in terms of versatility.

[0031] The hydroxyl groups at both ends of the above structure may be directly bonded to the polydiene structure or bonded via a bonding chain. Examples of such bonding chains include hydrocarbon chains such as alkylene chains, alkenylene chains, alkylylene chains, phenylene chains, and naphthylene chains (these hydrocarbons may be substituted with halogens such as fluorine, chlorine, or bromine), as well as -CO-, -COCO-, -CO(CH2)mCO- (m=1~10), etc. Among these, alkylene chains are preferred because they do not hinder the effects of the present invention. Furthermore, the above bonding chains may be used individually or in combination of two or more types.

[0032] Furthermore, the number-average molecular weight of the above polydiene diols (a2-1) is preferably 500 to 10000, more preferably 1000 to 7000, and particularly preferably 1500 to 5000, from the viewpoint of excellent dielectric properties.

[0033] The hydrogenation rate of the hydrogenated polybutadienediol is not particularly limited, but is preferably 80% or more, and particularly preferably 90% or more. If the hydrogenation rate is low, the appearance of the polyester resin (A) deteriorates due to the presence of unsaturated groups, and gelation is more likely to occur during the manufacturing of the polyester resin (A), making manufacturing difficult. The upper limit is usually 100%.

[0034] The polybutadiene diols (a2-1) preferably have side chains, and the proportion of side chains to the total polybutadiene diols (a2-1) is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and most preferably 40% or more. The proportion (%) of the side chains to the total is calculated by the following equation 2. [Formula 2] Percentage of side chains relative to the total (%) = Number of carbon atoms in side chains / Total number of carbon atoms × 100

[0035] In the polyester resin (A) used in the present invention, from the viewpoint of dielectric properties, the content of structural parts derived from polydiene diols (a2-1) in the structural parts derived from polyhydric alcohols (a2) must be 20 mol% or more, preferably 50 to 100 mol%, and particularly preferably 70 to 97 mol%. If the content of structural parts derived from polydiene diols (a2-1) is too low, the low hygroscopicity, dielectric properties, and tackiness will be inferior.

[0036] Furthermore, the content of structural parts derived from polydiene diols (a2-1) relative to the total polyester resin (A) is preferably 20 to 99% by weight, more preferably 30 to 98% by weight, and even more preferably 40 to 97% by weight. If the content of structural parts derived from polydiene diols (a2-1) is too low, the low hygroscopicity, dielectric properties, and tackiness tend to be poor, and if it is too high, the compatibility with additives tends to be poor.

[0037] Furthermore, in the present invention, from the viewpoint of low dielectric loss tangent, it is also preferable that the total of the structural sites derived from the aromatic polycarboxylic acids (a1-1) and the structural sites derived from the polydiene diols (a2-1) be 90% by weight or more of the polyester resin (A). More preferably, it is 95% by weight or more.

[0038] The sum of the structural sites derived from the above aromatic polycarboxylic acids (a1-1) and the polydiene diols (a2-1) can be calculated using the following formula 3. [Formula 3] The total weight %) of structural sites derived from polycarboxylic acids (a1-1) and polydienediols (a2-1) = [Weight of structural sites derived from aromatic polycarboxylic acids (a1-1) + Weight of polydienediols (a2-1)] / Total weight of polyester resin (A) × 100

[0039] In the present invention, the polyester resin (A) preferably contains aromatic polycarboxylic acids (a1-1) and polydienediols (a2-1) in a well-balanced manner, and the weight ratio of aromatic polycarboxylic acids (a1-1) to polydienediols (a2-1) in the polyester resin (A) [(a1-1) / (a2-1)] is usually 0.001 to 1, and preferably 0.01 to 0.1.

[0040] Examples of dimer ols that constitute the structural sites derived from the aforementioned dimer ols include diols derived from dimer acids of unsaturated fatty acid dimers having an average of 10 to 26 carbon atoms (preferably 12 to 24, more preferably 14 to 22). Specifically, examples include diols derived from unsaturated fatty acids such as oleic acids, linoleic acids, linolenic acids, and erucic acids.

[0041] Examples of bisphenol skeleton-containing monomers that constitute the structural sites derived from the bisphenol skeleton-containing monomers include bisphenol A, bisphenol B, bisphenol E, bisphenol F, bisphenol AP, bisphenol BP, bisphenol P, bisphenol PH, bisphenol S, bisphenol Z, 4,4'-dihydroxybenzophenone, bisphenol fluorene, and their hydrogenated derivatives, as well as those obtained by adding 1 to several moles of ethylene oxide or propylene oxide to the hydroxyl group of bisphenols. Examples include glycols such as ethylene oxide adducts and propylene oxide adducts.

[0042] Examples of aliphatic polyhydric alcohols that constitute the structural site derived from the aliphatic polyhydric alcohol include aliphatic diols such as ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 1,10-decanediol, 2-ethyl-2-butylpropanediol, 2,4-diethyl-1,5-pentanediol, and 2,2,4-trimethyl-1,3-pentanediol, as well as trivalent or higher aliphatic polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. Among these, ethylene glycol and trimethylolpropane are preferred.

[0043] Examples of alicyclic polyhydric alcohols that constitute the structural site derived from the alicyclic polyhydric alcohol include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, tricyclodecanediol, tricyclodecanedimethanol, and spiroglycol.

[0044] The aromatic polyhydric alcohols that constitute the structural site derived from the aromatic polyhydric alcohols are those other than the bisphenol skeleton-containing monomers, and include, for example, paraxylene glycol, metaxylene glycol, orthoxylene glycol, 1,4-phenylene glycol, and ethylene oxide adducts of 1,4-phenylene glycol.

[0045] Furthermore, other examples of aromatic polyhydric alcohols include fluorene diols represented by the following general formula (1). [ka]

[0046] If the polyester resin (A) contains structural sites derived from dimer ols, structural sites derived from bisphenol skeleton-containing monomers, structural sites derived from aliphatic polyhydric alcohols, structural sites derived from alicyclic polyhydric alcohols, and structural sites derived from aromatic polyhydric alcohols, the total content of structural sites derived from dimer ols, structural sites derived from bisphenol skeleton-containing monomers, structural sites derived from aliphatic polyhydric alcohols, structural sites derived from alicyclic polyhydric alcohols, and structural sites derived from aromatic polyhydric alcohols in the polyhydric alcohol-derived structural sites is preferably 50 mol% or less, more preferably 30 mol% or less, and particularly preferably The percentage is 20 mol% or less.

[0047] Furthermore, if the polyester resin (A) contains structural moieties derived from aliphatic polyhydric alcohols, the content of structural moieties derived from aliphatic polyhydric alcohols in the structural moieties derived from polyhydric alcohols (a2) is preferably 30 mol% or less, more preferably 20 mol% or less, and particularly preferably 15 mol% or less.

[0048] Structural sites derived from polyhydric alcohols (a2) preferably include polydiene diols (a2-1) and aliphatic polyhydric alcohols in terms of dielectric properties and productivity.

[0049] The polyester resin (A) used in the present invention preferably has at least one structural site selected from the group consisting of structural sites derived from trivalent or higher aromatic polycarboxylic acids and structural sites derived from trivalent or higher aliphatic polyhydric alcohols, for the purpose of introducing a branched skeleton. In other words, it is preferable that the copolymer component of the polyester resin (A) contains at least one selected from the group consisting of trivalent or higher aromatic polycarboxylic acids and trivalent or higher aliphatic polyhydric alcohols. In particular, when a crosslinked structure is formed by reacting with a crosslinking agent (B) described later, introducing a branched skeleton increases the reaction sites of the resin, making it possible to obtain a strong adhesive layer with high crosslink density. Among these, it is preferable that trimellitic acid or its anhydride or trimethylolpropane is included for versatility. When using trivalent or higher polycarboxylic acids with 0 or 1 acid anhydride group in the depolymerization reaction described later, it is preferable to use trivalent or higher aromatic polycarboxylic acids separately from the polycarboxylic acids used in the depolymerization reaction.

[0050] When at least one selected from the group consisting of trivalent or higher aromatic polycarboxylic acids and trivalent or higher aliphatic polyhydric alcohols is used for the purpose of introducing a branched skeleton into a polyester resin (A), the content of trivalent or higher aromatic polycarboxylic acids relative to the total polycarboxylic acids (a1), or the content of trivalent or higher polyhydric alcohols relative to the total polyhydric alcohols (a2) (excluding trivalent or higher polycarboxylic acids with 0 or 1 acid anhydride group used in the depolymerization reaction) is preferably in the range of 0.1 to 10 mol%, more preferably 0.3 to 5 mol%, and even more preferably 0.5 to 3 mol%, respectively. If the content of both or either is too high, the mechanical properties of the coating film formed by applying the adhesive will decrease, such as the elongation at the breaking point, and the adhesive strength will tend to decrease, and gelation will tend to occur during polymerization.

[0051] Furthermore, the polyester resin (A) used in the present invention may contain structural moieties derived from oxycarboxylic acid compounds. The oxycarboxylic acid compounds mentioned above are compounds that have a hydroxyl group and a carboxyl group in their molecular structure. Examples of oxycarboxylic acid compounds that constitute the structural site derived from the above-mentioned oxycarboxylic acid compounds include 5-hydroxyisophthalic acid, p-hydroxybenzoic acid, p-hydroxyphenylpropionic acid, p-hydroxyphenylacetic acid, 6-hydroxy-2-naphthoic acid, and 4,4-bis(p-hydroxyphenyl)valeric acid. These may be used individually or in combination of two or more.

[0052] [Glass transition temperature (Tg) of polyester resin (A)] The glass transition temperature (Tg) of the polyester resin (A) used in the present invention is preferably 0°C or lower, more preferably -70 to -5°C, particularly preferably -60 to -10°C, even more preferably -50 to -15°C, especially preferably -40 to -20°C, and most preferably -35 to -25°C. If the glass transition temperature (Tg) is too low, the dielectric properties tend to be poor, and if the glass transition temperature (Tg) is too high, the tack properties tend to be insufficient.

[0053] The method for measuring the glass transition temperature (Tg) is as follows: The glass transition temperature (Tg) can be determined by measuring it using a differential scanning calorimeter. The measurement conditions are a temperature range of -90 to 100°C and a temperature rise rate of 10°C / min.

[0054] [Acid value of polyester resin (A)] The acid value of the polyester resin (A) used in the present invention is preferably 10 mgKOH / g or less, more preferably 5 mgKOH / g or less, particularly preferably 3 mgKOH / g or less, even more preferably 2 mgKOH / g or less, and most preferably 1 mgKOH / g or less. The lower limit is usually 0 mgKOH / g. If the acid value is too high, it becomes necessary to incorporate a certain amount of crosslinking agent such as epoxy from the standpoint of humid heat resistance. This makes it difficult to adjust the gel fraction of the adhesive layer to the desired value, and tends to make it difficult to obtain the desired adhesive properties.

[0055] The definition and measurement method of acid value are as follows: The acid value (mgKOH / g) can be determined by dissolving 1 g of polyester resin (A) in 30 g of a toluene / methanol mixed solvent (for example, toluene / methanol = 7 / 3 by volume) and performing a neutralization titration according to JIS K 0070. In this invention, the acid value of the polyester resin (A) is determined by the content of carboxyl groups in the resin.

[0056] [Hydroxyl value of polyester resin (A)] Furthermore, the hydroxyl value of the above-mentioned polyether resin (A) is preferably 1 mg KOH / g or more, more preferably 2 to 30 mg KOH / g, even more preferably 3 to 20 mg KOH / g, and particularly preferably 4 to 15 mg KOH / g. If the hydroxyl value is too low, it becomes difficult to adjust the gel fraction of the adhesive layer to the desired value, and it tends to become difficult to obtain the desired adhesive properties. If the hydroxyl value is too high, the dielectric properties, especially the dielectric loss tangent, tend to be poor.

[0057] The hydroxyl value of the above polyester resin (A) is determined by neutralization titration in accordance with JIS K 0070.

[0058] The ester group concentration of the polyester resin (A) is preferably 3.0 mmol / g or less, more preferably 0.1 to 2.1 mmol / g, and even more preferably 0.2 to 1.0 mmol / g. If the ester group concentration is too low, the polarity and elastic modulus of the polyester resin (A) tend to decrease, resulting in poor cohesive force, while if it is too high, it tends to adversely affect the dielectric properties.

[0059] The ester group concentration (millimoles / g) mentioned above refers to the number of moles of ester groups in 1g of polyester resin (A), and can be calculated, for example, from the amount used. This calculation method involves dividing the number of moles of the polycarboxylic acid (a1) and polyhydric alcohol (a2) used in the charge by the total weight of the finished product. An example of the calculation formula is shown below. Furthermore, if the amounts of polycarboxylic acids (a1) and polyhydric alcohols (a2) added are the same in molar amounts, either of the following calculation formulas may be used. Furthermore, when using monomers that possess both carboxylic acid and hydroxyl groups, or when preparing polyesters from caprolactone, etc., the calculation method will need to be changed accordingly.

[0060] <When polycarboxylic acids (a1) are low> Ester group concentration (millimoles / g) = [(A1 / α1×m1 + A2 / α2×m2 + A3 / α3×m3···) / Z] × 1000 A: Amount of polycarboxylic acids (a1) to be charged (g) α: Molecular weight of polycarboxylic acids (a1) m: Number of carboxyl groups per molecule of polycarboxylic acids (a1) Z: Finished weight (g)

[0061] <When polyhydric alcohols (a2) are low> Ester group concentration (millimoles / g) = [(B1 / β1×n1 + B2 / β2×n2 + B3 / β3×n3···) / Z] × 1000 B: Amount of polyhydric alcohol (a2) added (g) β: Molecular weight of polyhydric alcohols (a2) n: Number of hydroxyl groups per molecule of polyhydric alcohols (a2) Z: Finished weight (g)

[0062] Furthermore, the ester group concentration can also be measured using known methods such as NMR. For example, the determination of the ester group concentration, composition, and composition ratio of polyester resin (A) is performed at a resonance frequency of 400 MHz. 1 H-NMR measurement (proton-type nuclear magnetic resonance spectroscopy), 13 This can be done using 1C-NMR (carbon-type nuclear magnetic resonance spectroscopy).

[0063] Furthermore, the concentration of polar groups other than ester groups and reactive functional groups in the polyester resin (A) is preferably low in terms of low hygroscopicity and long-term durability in a humid and hot environment. Other polar groups include, for example, amide groups, imide groups, urethane groups, urea groups, ether groups, and carbonate groups.

[0064] The concentrations of amide groups, imide groups, urethane groups, and urea groups in the polyester resin (A) are preferably 3 mmol / g or less in total, more preferably 2 mmol / g or less, particularly preferably 1 mmol / g or less, even more preferably 0.5 mmol / g or less, and most preferably 0.2 mmol / g or less.

[0065] Examples of the ether groups mentioned above include alkyl ether groups and phenyl ether groups, and it is particularly preferable to lower the concentration of alkyl ether groups in terms of low hygroscopicity and long-term durability in humid and hot environments. The alkyl ether group concentration of the polyester resin (A) is preferably 3 mmol / g or less, more preferably 2 mmol / g or less, particularly preferably 1.5 mmol / g or less, even more preferably 1 mmol / g or less, and most preferably 0.5 mmol / g or less. Furthermore, the phenyl ether group concentration of the polyester resin (A) is preferably 5 mmol / g or less, more preferably 4 mmol / g or less, particularly preferably 3 mmol / g or less, and even more preferably 2.5 mmol / g or less.

[0066] The carbonate group concentration of polyester resin (A) is 3 mmol / g or less. It is preferable that the concentration is 2 mmol / g or less, more preferably 1 mmol / g or less, even more preferably 0.5 mmol / g or less, and most preferably 0.2 mmol / g or less.

[0067] [Peak-top molecular weight (Mp) and weight-average molecular weight (Mw) of polyester resin (A)] The peak top molecular weight (Mp) of the polyester resin (A) used in the present invention is preferably 5,000 to 150,000, more preferably 10,000 to 120,000, particularly preferably 15,000 to 100,000, and even more preferably 20,000 to 80,000. If the peak-top molecular weight (Mp) is too low, it tends to result in insufficient hygroscopicity, long-term durability in humid and hot environments, and poor retention. Conversely, if the peak-top molecular weight (Mp) is too high, it tends to result in insufficient adhesion or excessively high solution viscosity during application, making it difficult to obtain a uniform coating film. There is.

[0068] The weight-average molecular weight (Mw) of the polyester resin (A) used in the present invention is preferably 5,000 to 500,000, more preferably 10,000 to 300,000, particularly preferably 20,000 to 200,000, even more preferably 30,000 to 150,000, and especially preferably 50,000 to 130,000. If the weight-average molecular weight (Mw) is too low, it tends to result in insufficient hygroscopicity, long-term durability in humid and hot environments, and poor retention. Conversely, if the weight-average molecular weight (Mw) is too high, it tends to result in insufficient adhesion or excessively high solution viscosity during application, making it difficult to obtain a uniform coating film.

[0069] The methods for measuring peak-top molecular weight (Mp) and weight-average molecular weight (Mw) are as follows: Peak top molecular weight (Mp) and weight-average molecular weight (Mw) were determined using a high-performance liquid chromatograph (Tosoh Corporation, "HLC-8320GPC") with a column (TSKgel SuperMultipore HZ-M (exclusion limit molecular weight: 2 × 10⁻¹⁶)). 6 The molecular weight can be determined by measuring two polystyrene polymers connected in series (theoretical plate count: 16,000 stages / piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 4 μm) and converting them to standard polystyrene molecular weight.

[0070] [Water absorption rate (by weight) of polyester resin (A)] The water absorption rate of the polyester resin (A) used in the present invention is preferably 2% by weight or less, more preferably 1% by weight or less, particularly preferably 0.8% by weight or less, and even more preferably 0.6% by weight or less. The lower limit is usually 0% by weight. If the water absorption rate is too high, it tends to reduce moisture heat resistance, insulation reliability, and have inferior dielectric properties.

[0071] The method for measuring the water absorption rate is as follows: A polyester resin (A) solution (without the crosslinking agent (B) described later) is applied to a release film using an applicator and dried at 120°C for 10 minutes to produce a sheet with a dry thickness of 65 μm of the polyester resin (A) layer. This sheet is cut to a size of 7.5 cm x 11 cm, and the polyester resin (A) layer side of the sheet is laminated onto a glass plate whose weight has been measured in advance, after which the release film is peeled off. By laminating six of these polyester resin (A) layers, a test plate with a polyester resin layer with a thickness of 390 μm on a glass plate is obtained, and Measure its weight. The test plate obtained in this manner is immersed in purified water at 23°C for 24 hours, then removed, the surface moisture is wiped off, its weight is measured, and it is dried at 70°C for 2 hours. The weight of the dried test plate is then measured. From the weight measured in each of these steps, the water absorption rate (by weight) is calculated according to formula 4 below. [Formula 4] Water absorption rate (weight%)=(cd) / (ba)×100 a: Weight of the glass plate alone b: Weight of the initial test board c: Weight of the test plate immediately after removing it from purified water and wiping off the moisture. d: Weight of the test plate after drying at 70°C for 2 hours.

[0072] [Dielectric properties of polyester resin (A)] (Dielectric constant (Dk)) The dielectric constant of the polyester resin (A) used in the present invention at a temperature of 23°C and a relative humidity of 50% RH at a frequency of 10 GHz is preferably 2.8 or less, more preferably 2.5 or less, particularly preferably 2.3 or less, and even more preferably 2.2 or less. If the dielectric constant is too high, the transmission speed tends to decrease and the transmission loss tends to increase.

[0073] (Dielectric loss tangent (Df)) The dielectric loss tangent of the polyester resin (A) used in the present invention at a temperature of 23°C and a relative humidity of 50% RH at a frequency of 10 GHz is preferably 0.01 or less, more preferably 0.008 or less, even more preferably 0.006 or less, particularly preferably 0.005 or less, even more preferably 0.004 or less, especially preferably 0.003 or less, and most preferably 0.002 or less. Most preferably 0.0015 or less, as excessively high dielectric loss tangents tend to increase transmission loss.

[0074] The above dielectric constant and dielectric loss tangent can be determined by the cavity resonator perturbation method using a network analyzer. If the polyester resin (A) is highly tacky and difficult to prepare as a standalone sample, the dielectric properties of the polyester resin (A) alone can be calculated by measuring it sandwiched between films and subtracting the film's weight.

[0075] Furthermore, in the present invention, it is preferable that the polyester resin (A) is an amorphous polyester resin in terms of solvent solubility, solution stability, tackiness, transparency, etc. If it is crystalline, solvent solubility, solution stability, tackiness, transparency, etc. tend to be insufficient. Non-crystalline properties can be confirmed by differential scanning calorimetering. For example, when measured within a temperature range of -90 to 400°C and a temperature rise rate of 10°C / min, no endothermic peak due to crystalline melting is observed. The temperature range and heating rate can be appropriately adjusted depending on the sample.

[0076] The content of polyester resin (A) in the adhesive composition is preferably 70% by weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more, and most preferably 95% by weight or more, in terms of dielectric properties.

[0077] [Manufacturing of polyester resin (A)] The polyester resin (A) of the present invention can be produced by using the above-mentioned polycarboxylic acids (a1) and polyhydric alcohols (a2) as raw materials and carrying out a polycondensation reaction in the presence of a catalyst by a known method. That is, since the polyester resin (A) is obtained by a polycondensation reaction of polycarboxylic acids (a1) and polyhydric alcohols (a2), it will have structural parts derived from polycarboxylic acids (a1) and structural parts derived from polyhydric alcohols (a2). In the above polycondensation reaction, an esterification reaction or transesterification reaction is carried out first, followed by the polycondensation reaction. If it is not necessary to make it high molecular weight It can also be produced solely by esterification or transesterification reactions.

[0078] The preferred blending ratio of polyhydric carboxylic acids (a1) and polyhydric alcohols (a2) is 1 to 3 equivalents of polyhydric alcohols (a2) per equivalent of polyhydric carboxylic acids (a1), particularly preferably 1.1 to 2.2 equivalents, and even more preferably 1.2 to 1.7 equivalents. If the blending ratio of polyhydric alcohols (a2) is too low, the acid value tends to increase, making it difficult to increase the molecular weight, and if it is too high, the yield tends to decrease.

[0079] [Esterification reaction, or transesterification reaction] In esterification or transesterification reactions, catalysts are typically used. Specifically, examples include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, antimony-based catalysts such as antimony trioxide, germanium-based catalysts such as germanium dioxide, and catalysts such as zinc acetate, manganese acetate, and dibutyltin oxide. One or more of these are used. Among these, antimony trioxide, tetrabutyl titanate, germanium dioxide, and zinc acetate are preferred due to the balance between high catalytic activity and the color of the resulting reactants.

[0080] The amount of the catalyst is preferably 1 to 10,000 ppm relative to the total copolymerization components (by weight), particularly preferably 10 to 5,000 ppm, and even more preferably 20 to 3,000 ppm. If the amount is too low, the polymerization reaction tends not to proceed sufficiently, and if it is too high, there is no advantage such as shortening the reaction time, and side reactions tend to occur.

[0081] The reaction temperature during esterification or transesterification reactions is preferably 200-300°C, particularly preferably 210-280°C, and even more preferably 220-260°C. If the reaction temperature is too low, the reaction tends not to proceed sufficiently, and if it is too high, side reactions such as decomposition tend to occur. In addition, although the reaction pressure is usually atmospheric pressure, it is also preferable to raise the reaction temperature by pressurizing the reaction to proceed more efficiently.

[0082] The reaction conditions for the polycondensation reaction, which is carried out after the esterification or transesterification reaction described above, are preferably such that an equivalent amount of the catalyst used in the esterification or transesterification reaction is added, the reaction temperature is preferably 220-280°C, particularly preferably 230-270°C, and the reaction system is gradually reduced in pressure until the final reaction is carried out at 5 hPa or less. If the reaction temperature is too low, the reaction tends not to proceed sufficiently, and if it is too high, side reactions such as decomposition tend to occur.

[0083] Furthermore, in order to obtain a polyester resin having a carboxyl group in its side chain, a method of reacting a polycarboxylic acid anhydride with a hydroxyl group-containing prepolymer obtained by copolymerizing polycarboxylic acids (a1), excluding polycarboxylic acid anhydrides, is preferred in terms of productivity.

[0084] The esterification reaction between polycarboxylic acids (a1) and polyhydric alcohols (a2) is typically carried out at a temperature of 180-280°C, with a reaction time of typically 60 minutes to 8 hours.

[0085] The temperature during polycondensation is typically 200-280°C, and the reaction time is typically 20 minutes to 4 hours. Furthermore, polycondensation is preferably carried out under reduced pressure.

[0086] Furthermore, polyester resin (A) can be produced by a well-known method other than those described above, for example, by subjecting polycarboxylic acids (a1) and polyhydric alcohols (a2) to an esterification reaction, optionally in the presence of a catalyst, to obtain a prepolymer, followed by polycondensation and then depolymerization.

[0087] For depolymerization, it is preferable to use polycarboxylic acids with a valency of 3 or higher and having 0 or 1 acid anhydride groups, from the viewpoint of adhesion. As polycarboxylic acids with a valency of 3 or higher and having 0 or 1 acid anhydride groups, those described in polycarboxylic acids (a1) above can be used. In particular, from the viewpoint of suppressing molecular weight reduction, polycarboxylic acids with a valency of 3 or higher and having 1 acid anhydride group are preferred, more preferably trimellitic anhydride or hydrogenated trimellitic anhydride, and especially preferred trimellitic anhydride from the viewpoint of low dielectric loss tangent. The temperature during depolymerization is typically 200-260°C, and the reaction time is typically 10 minutes to 3 hours.

[0088] During depolymerization, if polycarboxylic acids (a1) with a total of 100 mol% are used in amounts exceeding 20 mol% of trivalent or higher polycarboxylic acids with 0 or 1 acid anhydride groups, the molecular weight of the resin may decrease significantly. Therefore, when polycarboxylic acids (a1) are totaled 100 mol%, it is preferable to perform depolymerization using 20 mol% or less of trivalent or higher polycarboxylic acids with 0 or 1 acid anhydride groups, more preferably 1 to 15 mol%, particularly preferably 2 to 10 mol%, and even more preferably 3 to 8 mol%.

[0089] Thus, a polyester resin (A) with a very small dielectric loss tangent compared to conventional resins can be obtained. Furthermore, polyester resins (A) with very low dielectric loss tangents are extremely useful as raw materials for adhesives used in bonding electronic material components, as they can suppress transmission loss in the high-frequency range.

[0090] Furthermore, in the present invention, it is preferable that the polyester resin (A) is soluble in a non-halogenated organic solvent, as this relates to the adhesive composition described later. If the solubility in such organic solvents is insufficient, it tends to become difficult to prepare the adhesive composition.

[0091] The above-mentioned non-halogenated organic solvents include, for example, aromatic solvents such as toluene, xylene, solvent naphtha, and Solvesso; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohol solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and isobutyl alcohol; ester solvents such as ethyl acetate and n-butyl acetate; acetate solvents such as cellosolve acetate and methoxyacetate; or mixtures of two or more of these solvents.

[0092] [Crosslinking agent (B)] In order to increase the cohesive force of this composition, it is preferable to crosslink the components. Specifically, it is preferable to further contain a crosslinking agent (B). By including the crosslinking agent (B), the functional groups in the polyester resin (A) react with the crosslinking agent (B), which has functional groups that react with these functional groups, and crosslink, thereby obtaining an adhesive with excellent tackiness, heat resistance, and durability. In addition, as with polyfunctional acrylates, the crosslinking agents may react with each other and create entanglement with the polyester resin (A), resulting in pseudo-crosslinking. Examples of such crosslinking agents (B) include polyisocyanate compounds (b1), polyepoxy compounds, polyfunctional (meth)acrylic monomers, and polyfunctional urethane (meth)acrylates. Among these, compounds having a functional group that reacts with at least one of the hydroxyl group and carboxyl group contained in the polyester resin (A) are preferred, and among these, polyisocyanate compounds (b1) are preferred in terms of reactivity and ease of adjusting the gel fraction.

[0093] Examples of the above polyisocyanate compound (b1) include tolylene diisocyanate crosslinking agents such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, xylylene diisocyanate crosslinking agents such as 1,3-xylylene diisocyanate, diphenylmethane crosslinking agents such as diphenylmethane-4,4-diisocyanate, naphthalene diisocyanate crosslinking agents such as 1,5-naphthalene diisocyanate, and aromatic isocyanate crosslinking agents; isophorone diisocyanate, 1,4-cyclohexanedi Examples include alicyclic isocyanate crosslinking agents such as socianates, 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, 1,3-diisocyanatomethylcyclohexane, and norbornane diisocyanate; aliphatic isocyanate crosslinking agents such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; and adducts, biuretes, and isocyanurates of the above isocyanate compounds. The above polyisocyanate compounds can also be used in which the isocyanate portion is blocked by phenol, lactam, etc. These polyvalent isocyanate compounds may be used individually or in mixtures of two or more. In particular, from the viewpoint of compatibility, alicyclic isocyanate crosslinking agents and aliphatic isocyanate crosslinking agents are preferred, alicyclic isocyanate crosslinking agents are especially preferred, and isocyanurate and adduct forms of isophorone diisocyanate are even more preferred.

[0094] The equivalent amount of isocyanate groups to hydroxyl groups is preferably 0.2 to 5, more preferably 0.3 to 3, particularly preferably 0.5 to 2, even more preferably 0.7 to 1.6, and most preferably 0.9 to 1.2. If the equivalent amount is too large, the adhesive strength and the long-term stability of the adhesive sheet tend to be insufficient. Conversely, if it is too small, the long-term durability and cohesive force in humid and hot environments tend to be insufficient, and the dielectric properties tend to be inferior.

[0095] Examples of the polyepoxy compounds mentioned above include: difunctional glycidyl ether types such as bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, and bromized bisphenol A diglycidyl ether; polyfunctional glycidyl ether types such as phenol novolac glycidyl ether and cresol novolac glycidyl ether; glycidyl ester types such as hexahydrophthalate glycidyl ester and dimer acid glycidyl ester; and alicyclic or fatty compounds such as triglycidyl isocyanurate, 3,4-epoxycyclohexylmethylcarboxylate, epoxidized polybutadiene, and epoxidized soybean oil. Examples include polyepoxides. One or more of these polyepoxy compounds can be used. Among them, glycidyl ether type and glycidyl ester type are preferred from the viewpoint of reactivity, glycidyl ether type is preferred from the viewpoint of moist heat resistance, and polyfunctional type is preferred from the viewpoint of heat resistance.

[0096] Furthermore, the epoxy equivalent of the polyepoxy compound is preferably 500 g / eq or less, more preferably 350 g / eq or less, particularly preferably 250 g / eq or less, and even more preferably 200 g / eq or less. If the epoxy equivalent of the polyepoxy compound is too high, the crosslinking density after crosslinking will be low, resulting in poor heat resistance, or a large amount of polyepoxy compound will need to be added to increase the crosslinking density, which tends to result in poor dielectric properties.

[0097] Furthermore, if the polyepoxy compound contains a nitrogen atom (nitrogen atom-containing polyepoxy compound), the aging time of the adhesive layer can be shortened, which is preferable.

[0098] Examples of nitrogen atom-containing polyepoxy compounds include tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, tetraglycidylbisaminomethylcyclohexanone, and glycidylamine compounds such as N,N,N',N'-tetraglycidyl-m-xylenediamine.

[0099] The equivalent amount of epoxy groups to carboxyl groups is preferably 0.8 to 5, more preferably 0.9 to 3, particularly preferably 1 to 2.5, and even more preferably 1.2 to 2. If the equivalent is too large, it tends to result in insufficient adhesion and low moisture absorption, or poor dielectric properties. Conversely, if it is too small, it tends to result in insufficient long-term durability and heat resistance in humid and hot environments.

[0100] The equivalent amount of epoxy groups to carboxyl groups (COOH) can be determined from the acid value of the polyester resin (A) and the epoxy equivalent (g / eq) of the compounded polyepoxy compound using the following formula 5. [Formula 5] Equivalent amount of epoxy relative to COOH = (a ÷ WPE) / (AV ÷ 56.1 ÷ 1000 × b) a: Weight (g) of the polyepoxy compound used in the formulation WPE: Epoxy equivalent (g / eq) of polyepoxy compounds AV: Acid value (mgKOH / g) of polyester resin (A) b: Weight (g) of the polyester resin (A) used in the formulation.

[0101] This composition, by containing a polyester resin (A) and a crosslinking agent (B), exhibits superior low dielectric properties, low hygroscopicity, high tackiness, and long-term durability in humid and hot environments.

[0102] If the composition contains a crosslinking agent (B), the amount of crosslinking agent (B) is preferably 30 parts by weight or less, more preferably 0.1 to 20 parts by weight, particularly preferably 0.5 to 10 parts by weight, and even more preferably 1 to 5 parts by weight, per 100 parts by weight of polyester resin (A). If the amount of crosslinking agent (B) is too low, the heat resistance, holding power, adhesiveness, and long-term durability in a humid and hot environment tend to be insufficient, while if it is too high, the adhesiveness and low moisture absorption tend to be insufficient, or the dielectric properties tend to be poor.

[0103] Furthermore, in addition to the polyester resin (A) and crosslinking agent (B), the present invention may also incorporate a urethane catalyst (C), a hydrolysis inhibitor, a tackifying resin, an antioxidant, and the like.

[0104] <Urethane catalyst (C)> From the viewpoint of reaction rate, it is more preferable for this composition to contain a urethane catalyst (C).

[0105] Examples of urethane catalysts (C) include organometallic compounds and tertiary amine compounds. These can be used individually or in combination of two or more.

[0106] Examples of the above-mentioned organometallic compounds include zirconium compounds, iron compounds, tin compounds, titanium compounds, lead compounds, cobalt compounds, and zinc compounds.

[0107] Examples of the zirconium-based compounds mentioned above include zirconium naphthenate and zirconium acetylacetonate. Examples of the iron-based compounds mentioned above include iron acetylacetonate and iron 2-ethylhexanoate. Examples of the tin-based compounds mentioned above include dibutyltin dichloride, dibutyltin oxide, and dibutyltin dilaurate. Examples of the above-mentioned titanium-based compounds include dibutyltitanium dichloride, tetrabutyltitanate, and butoxytitanium trichloride. Examples of the lead-based compounds mentioned above include lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate. Examples of the above-mentioned cobalt-based compounds include cobalt 2-ethylhexanoate and cobalt benzoate. Examples of the zinc-based compounds mentioned above include zinc naphthenate and zinc 2-ethylhexanoate. Examples of the above-mentioned tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo-(5,4,0)-undecene-7.

[0108] Among these urethane catalysts (C), organometallic compounds are preferred in terms of reaction rate and pot life of the adhesive layer, and zirconium compounds are particularly preferred. Furthermore, it is preferable to use acetylacetone in combination with the urethane catalyst as a catalytic inhibitor. The inclusion of acetylacetone is preferable because it suppresses catalytic activity in the solution state and extends the pot life.

[0109] The content of the urethane catalyst (C) is preferably 0.0001 to 1 part by weight, more preferably 0.001 to 0.1 parts by weight, and particularly preferably 0.01 to 0.05 parts by weight, per 100 parts by weight of polyester resin (A). If the content is too low, the aging time until the crosslinking reaction is completed tends to be longer, and if it is too high, the pot life tends to deteriorate and it tends to be difficult to control the physical properties.

[0110] [Hydrolysis inhibitors] The above-mentioned hydrolysis inhibitor is included to ensure the long-term durability of the adhesive composition. Conventional hydrolysis inhibitors can be used, for example, compounds that react and bond with the carboxyl group terminus of the polyester resin (A). Specifically, examples include compounds containing functional groups such as carbodiimide groups, epoxy groups, and oxazoline groups (excluding the aforementioned crosslinking agent (B)). Among these, carbodiimide group-containing compounds are preferred because they have a high effect in eliminating the catalytic activity of protons derived from the carboxyl group terminus.

[0111] As the above-mentioned carbodiimide group-containing compound, it is usually sufficient to use a known carbodiimide having one or more carbodiimide groups (-N=C=N-) in its molecule. However, to improve durability under high temperature and high humidity conditions, it is preferable to use a compound containing two or more carbodiimide groups in its molecule, i.e., a polyvalent carbodiimide compound, and in particular, a compound containing three or more carbodiimide groups, more preferably five or more, and especially seven or more. Note that the number of carbodiimide groups in a molecule is usually 50 or less, and if there are too many carbodiimide groups, the molecular structure becomes too large, which tends to reduce compatibility. It is also preferable to use a high molecular weight polycarbodiimide produced by decarboxylation condensation of diisocyanate in the presence of a midification catalyst.

[0112] Furthermore, high molecular weight polycarbodiimides in which the terminal isocyanate groups are encapsulated by a encapsulant are preferable in terms of storage stability. Examples of encapsulants include compounds having active hydrogen that reacts with isocyanate groups, or compounds having isocyanate groups. Examples include monoalcohols, monocarboxylic acids, monoamines, and monoisocyanates having one substituent selected from carboxyl groups, amino groups, and isocyanate groups. It can be done.

[0113] Examples of such high molecular weight polycarbodiimides include those obtained by decarboxylation condensation of the following diisocyanates.

[0114] Examples of such diisocyanates include 4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, etc., which can be used individually or in combination of two or more. Such high molecular weight polycarbodiimides may be synthesized or commercially available.

[0115] Examples of commercially available carbodiimide group-containing compounds include the Carbodilite® series manufactured by Nisshinbo Chemical Co., Ltd., and among these, Carbodilite V-01, V-02B, V-03, V-04K, V-04PF, V-05, V-07, V-09, and V-09GB are preferred due to their excellent compatibility with organic solvents.

[0116] As the epoxy group-containing compound, for example, glycidyl ester compounds and glycidyl ether compounds are preferred.

[0117] Specific examples of the above glycidyl ester compounds include, for example, glycidyl benzoate, t-bu-glycidyl benzoate, p-glycidyl toluate, glycidyl cyclohexanecarboxylic acid, glycidyl pelargonic acid, glycyl stearate, glycidyl laurate, glycidyl palmitate, glycidyl behenate, glycidyl versatate, glycidyl oleate, glycidyl linoleate, glycidyl linolenic acid, glycidyl behenolate, glycidyl stearolate, and glycidyl terephthalate. Examples include lysidyl esters, diglycidyl isophthalate, diglycidyl phthalate, diglycidyl naphthalenedicarboxylate, diglycidyl methylterephthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, diglycidyl cyclohexanedicarboxylate, diglycidyl adipicate, diglycidyl succinate, diglycidyl sebacate, diglycidyl dodecandionate, diglycidyl octadecanedicarboxylate, triglycidyl trimelliticate, tetraglycidyl pyromelliticate, and others. These can be used individually or in combination of two or more types.

[0118] Specific examples of the above glycidyl ether compounds include, for example, phenylglycidyl ether, o-phenylglycidyl ether, 1,4-bis(β,γ-epoxypropoxy)butane, 1,6-bis(β,γ-epoxypropoxy)hexane, 1,4-bis(β,γ-epoxypropoxy)benzene, 1-(β,γ-epoxypropoxy)-2-ethoxyethane, 1-(β,γ-epoxypropoxy)-2-benzyloxyethane, 2,2-bis-[r-(β,γ-epoxypropoxy)phenyl]propane, 2,2-bis-(4-hydroxyphenyl)propane, 2,2-bis-(4-hydroxyphenyl)methane, etc. Examples include bisglycidyl polyethers obtained by the reaction of sphenol and epichlorohydrin, which can be used individually or in combination of two or more.

[0119] As the oxazoline group-containing compound, bisoxazoline compounds are preferred. Specifically, for example, 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(4,4-dimethyl-2-oxazoline), 2,2'-bis(4-ethyl-2-oxazoline), 2,2'-bis(4,4'-diethyl-2-oxazoline), 2,2'-bis(4-propyl-2-oxazoline), 2,2'-bis(4-butyl-2-oxazoline), 2,2'-bis(4-hexyl-2-oxazoline), 2,2'-bis(4-phenyl-2-oxazoline), 2,2'-bis(4-cyclohexyl-2-oxazoline), 2,2'-bis(4-benzyl-2-oxazoline), 2,2'-p-phenylenebis(2-oxazoline), 2,2'-m-phenylenebis(2-oxazoline), 2,2'-o-phenylenebis(2-oxazoline), 2,2'-p-phenylenebis(4-methyl-2-oxazoline), 2,2'-p-phenylenebis(4,4-methyl 2,2'-2-oxazoline), 2,2'-m-phenylenebis(4-methyl-2-oxazoline), 2,2'-m-phenylenebis(4,4-dimethyl-2-oxazoline), 2,2'-ethylenebis(2-oxazoline), 2,2'-tetramethylenebis(2-oxazoline), 2,2'-hexamethylenebis(2-oxazoline), 2,2'-octamethylenebis(2-oxazoline), 2,2'-decamethylenebis(2-oxazoline), 2,2'-e Examples include ethylenebis(4-methyl-2-oxazoline), 2,2'-tetramethylenebis(4,4-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethanebis(2-oxazoline), 2,2'-cyclohexylenebis(2-oxazoline), and 2,2'-diphenylenebis(2-oxazoline). Among these, 2,2'-bis(2-oxazoline) is the most preferred from the viewpoint of reactivity with polyester resin (A). These can be used individually or in combination of two or more.

[0120] These hydrolysis inhibitors are preferably low in volatility, and therefore, it is preferable to use those with a high number-average molecular weight. The number-average molecular weight of hydrolysis inhibitors is usually 300 to 10000, preferably 1000 to 5000. Furthermore, from the viewpoint of hydrolysis resistance, it is preferable to use a hydrolysis inhibitor with a high weight-average molecular weight. The weight-average molecular weight of the hydrolysis inhibitor is preferably 500 or more, more preferably 1000 or more, even more preferably 2000 or more, and particularly preferably 3000 or more. The upper limit of the weight-average molecular weight is usually 50000. If the molecular weight of the hydrolysis inhibitor is too small, the hydrolysis resistance tends to decrease. On the other hand, if the molecular weight is too large, the compatibility with polyester resin (A) tends to decrease.

[0121] Among hydrolysis inhibitors, it is preferable to use a compound containing a carbodiimide group, and in that case, the carbodiimide equivalent is preferably 50 to 10000, more preferably 100 to 1000, and even more preferably 150 to 500. Note that the carbodiimide equivalent refers to the chemical formula weight per carbodiimide group.

[0122] The content of the hydrolysis inhibitor is preferably 0.01 to 10 parts by weight, particularly preferably 0.1 to 5 parts by weight, and even more preferably 0.2 to 3 parts by weight, per 100 parts by weight of the polyester resin (A). If the content is too high, turbidity tends to occur due to poor compatibility with the polyester resin (A), and if it is too low, sufficient durability tends to be difficult to obtain.

[0123] Furthermore, the content of the hydrolysis inhibitor is preferably optimized according to the acid value of the polyester resin (A). The molar ratio [(y) / (x)] of the total number of moles of the hydrolysis inhibitor's functional groups in the adhesive composition to the total number of moles of the acidic functional groups of the polyester resin (A) in the adhesive composition (x) is preferably 0.5 ≤ (y) / (x), particularly preferably 1 ≤ (y) / (x) ≤ 1000, and even more preferably 1.5 ≤ (y) / (x) ≤ 100. If the molar ratio of (y) to (x) is too low, the moisture and heat resistance tends to decrease. On the other hand, if the molar ratio of (y) to (x) is too high, the compatibility with polyester resin (A) tends to decrease, and the adhesive strength, cohesive strength, and durability tend to decrease.

[0124] [Adhesion-enhancing resin] In the present invention, it is also preferable to include a tackifying resin, as this can improve the adhesive properties.

[0125] The tackifying resin mentioned above is not particularly limited, and conventionally known resins can be used. Examples of such tackifying resins include hydrocarbon-based tackifying resins, terpene-based resins, phenol-based resins, rosin-based resins, xylene-based resins, epoxy-based resins, polyamide-based resins, ketone-based resins, and elastomer-based resins. These may be used individually or in combination of two or more. Among these, hydrocarbon-based tackifying resins and terpene-based resins are preferred. Furthermore, it is particularly preferable that the tackifying resin contains at least one hydrocarbon-based tackifying resin, and that the hydrocarbon-based tackifying resin accounts for 30% by weight or more, preferably 50% by weight or more, and preferably 70% by weight or more of the total tackifying resin.

[0126] Examples of the hydrocarbon-based tackifying resins mentioned above include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic-aromatic petroleum resins (styrene-olefin copolymers, etc.), aliphatic-alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, and coumarone-indene resins. Examples of commercially available products include Mitsui Chemicals' "FTR6100," "FTR6110," and "FTR6125."

[0127] Examples of the above-mentioned terpene resins include terpene resins, terpene phenol resins, aromatically modified terpene resins, and specifically, α-pinene polymers, β-pinene polymers, dipentene polymers, and terpene resins obtained by phenol modification, aromatic modification, hydrogenation modification, or hydrocarbon modification of these can be used. In addition, commercially available products include, for example, "YS Polystar S145", "YS Resin PX1000", "YS Resin PX1250", "YS Polystar T145", "YS Resin TO115", and "YS" from Yasuhara Chemical Co., Ltd. Examples include "Polystar U130" and "Clearon P125," and terpene resins are preferred because they have good adhesion to non-polar substrates such as polypropylene.

[0128] As the phenolic resin mentioned above, for example, condensates of various phenols such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, and resorcinol with formaldehyde can be used. Furthermore, resols obtained by adding the phenols and formaldehyde under an alkaline catalyst, novolacs obtained by condensing the phenols and formaldehyde under an acid catalyst, rosins such as unmodified or modified rosins or their derivatives, and rosin-modified phenolic resins obtained by adding phenol under an acid catalyst and thermal polymerization can be used.

[0129] Examples of the rosin-based resins mentioned above include rosin resin, polymerized rosin resin, hydrogenated rosin resin, rosin ester resin, hydrogenated rosin ester resin, rosin phenol resin, polymerized rosin ester, etc. Specifically, unmodified rosin (raw rosin) such as gum rosin, wood rosin, and tall oil rosin, as well as modified rosins that have been hydrogenated, disproportionated, polymerized, or otherwise chemically modified, and their derivatives can be used. Examples of commercially available products include "Hariester TF," "Haritack 8LJA," "Haritack PH," "Haritack FK100," and "Haritack PCJ" manufactured by Harima Chemicals.

[0130] The tackifying resin preferably has an acid value of 30 mgKOH / g or less, more preferably 10 mgKOH / g or less, even more preferably 6 mgKOH / g or less, and particularly preferably 3 mgKOH / g or less. When multiple types of tackifying resins are used in combination, it is preferable that their average value is within the above range.

[0131] The softening point of the tackifying resin (measured, for example, by the ring-and-ball method) is preferably 80 to 170°C, more preferably 90 to 160°C, and even more preferably 100 to 150°C. Having a softening point within this range is preferable because it can improve the adhesive properties (adhesion strength, cohesive force).

[0132] In this invention, the tackifying resin is preferably plant-derived in order to protect the global environment. Examples of plant-derived tackifying resins include terpene resins and rosin resins, with terpene resins being particularly preferred.

[0133] Furthermore, from the viewpoint of compatibility, hydrocarbon-based tackifying resins and terpene-based resins are preferred, and hydrocarbon-based tackifying resins are particularly preferred.

[0134] The content of the tackifying resin is preferably 2 to 100 parts by weight, more preferably 5 to 50 parts by weight, even more preferably 8 to 30 parts by weight, and particularly preferably 10 to 20 parts by weight, per 100 parts by weight of the polyester resin (A). Having such a content within the above range is preferable because it can improve the adhesive properties (adhesion strength, cohesive force).

[0135] [Antioxidant] This composition is more preferably made to contain an antioxidant in order to improve the stability of the resin.

[0136] Examples of the above-mentioned antioxidants include hindered phenol antioxidants, amine antioxidants, sulfur antioxidants, and phosphoric acid antioxidants. Among these, it is preferable that at least one is selected from hindered phenol antioxidants, amine antioxidants, and phosphoric acid antioxidants, and an antioxidant consisting of a hindered phenol compound is particularly preferred. Examples of hindered phenol antioxidants include antioxidants having a hindered phenol structure in which a sterically hindered group such as a tert-butyl group is bonded to at least one of the adjacent carbon atoms of the carbon atom on the aromatic ring to which the hydroxyl group of phenol is bonded.

[0137] The antioxidant content is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 8 parts by weight, and even more preferably 0.05 to 5 parts by weight, per 100 parts by weight of polyester resin (A). If the content is too low, adhesive residue tends to be more likely to occur on the adherend, and if it is too high, the adhesive properties tend to decrease.

[0138] In addition to the polyester resin (A), crosslinking agent (B), urethane catalyst (C), hydrolysis inhibitor, tackifying resin, and antioxidant described above, this composition may also contain additives such as softeners, plasticizers, deelasticizing agents, UV absorbers, stabilizers, antistatic agents, silane coupling agents, fluxes, flame retardants, dispersants, emulsifiers, defoaming agents, leveling agents, ion trapping agents, catalysts, inorganic or organic fillers, metal powders, pigments, and other powders or particulate additives, as long as they do not impair the effects of the present invention. Furthermore, the composition may contain small amounts of impurities found in the raw materials used to manufacture the constituent components of this composition. These can be used individually or in combination of two or more types. If the composition contains the above-mentioned additives, the content of these components is preferably 70% by weight or less, more preferably 0.05 to 60% by weight, particularly preferably 0.1 to 50% by weight, and even more preferably 0.2 to 40% by weight.

[0139] This composition can be obtained, for example, by preparing the above-mentioned polyester resin (A) and any necessary optional components, and then blending and dispersing them during the production of the polyester resin (A), or by blending them into a solution of polyester resin (A) dissolved in an organic solvent and dispersing them using a mixing roller or the like.

[0140] Furthermore, solvents may be added to this composition to appropriately adjust its viscosity and facilitate handling when forming the coating film. The solvent is used to ensure the handling and workability of the composition during molding, and there are no particular restrictions on the amount used.

[0141] Examples of solvents include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate; ethers such as ethylene glycol monomethyl ether; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; alcohols such as methanol and ethanol; alkanes such as hexane and cyclohexane; and aromatics such as toluene and xylene. The solvents listed above may be used individually or mixed in any combination and ratio.

[0142] <Adhesives, bonding agents> In the present invention, by crosslinking this composition, an adhesive or bonding agent can be obtained that exhibits excellent effects in tackiness, tackiness, holding power, low hygroscopicity, long-term durability in humid and hot environments, and low dielectric properties. In this invention, "crosslinking" means intentionally crosslinking the composition by heat and / or light, and the degree of crosslinking can be controlled according to the desired physical properties and application.

[0143] The degree of crosslinking can be determined by the gel fraction of the adhesive or bonding agent, preferably 10-100% by weight, more preferably 15-90% by weight, particularly preferably 20-80% by weight, even more preferably 25-70% by weight, and especially preferably 40-65% by weight. If the gel fraction is too low, heat resistance, holding power, adhesive strength, and long-term durability in a humid and hot environment tend to be insufficient, while if it is too high, adhesive strength tends to be insufficient. The gel fraction mentioned above is an indicator of the degree of crosslinking and can be calculated, for example, by the following method: An adhesive sheet (without a release sheet) consisting of a polymer sheet (e.g., PET film) with an adhesive layer formed on it is wrapped in a 200-mesh stainless steel wire mesh and immersed in toluene at 23°C for 24 hours. The gel fraction is defined as the weight percentage of the insoluble adhesive component remaining in the wire mesh after immersion, relative to the weight of the adhesive component before immersion. However, the weight of the base material is subtracted.

[0144] <Adhesive sheets, laminates> Then, the adhesive layer of the present invention is formed from the above-mentioned adhesive, and an adhesive sheet or laminate having such an adhesive layer can be obtained. It is preferable that such an adhesive layer is formed on one or both sides of the support substrate. In this invention, the term "sheet" is used to include "film" and "tape" as well.

[0145] In other words, the adhesive layer of the present invention is formed from an adhesive in which an adhesive composition containing the aforementioned polyester resin (A) and crosslinking agent (B) is crosslinked.

[0146] The adhesive layer of the present invention has a dielectric loss tangent of 0.01 or less at a frequency of 10 GHz under a temperature of 23°C and a relative humidity of 50% RH. More preferably, it is 0.008 or less, particularly preferably 0.006 or less, even more preferably 0.005 or less, especially preferably 0.003 or less, and most preferably 0.0015 or less. If the dielectric loss tangent of such an adhesive layer is too high, the transmission loss will increase.

[0147] Furthermore, the dielectric constant of the adhesive layer at a frequency of 10 GHz under conditions of 23°C and 50% RH relative humidity is preferably 2.8 or less, more preferably 2.5 or less, particularly preferably 2.3 or less, and even more preferably 2.2 or less. If the dielectric constant is too high, the transmission speed tends to decrease and the transmission loss tends to increase.

[0148] The above-mentioned adhesive sheet or laminate can be manufactured, for example, as follows: Such adhesive sheets or laminates can be manufactured according to known general methods for manufacturing adhesive sheets. For example, the adhesive composition is applied to a substrate, dried, a release sheet is attached to the opposite side of the adhesive composition layer, and cured as necessary to obtain an adhesive sheet having an adhesive layer formed from the adhesive, a release sheet on one side of the adhesive layer, and a substrate on the other side, or a laminate having an adhesive layer and a substrate on one side of the adhesive layer. In the case of the above laminate, a laminate with a substrate attached instead of a release sheet may be used, that is, a laminate with a substrate on both sides of the adhesive layer.

[0149] Alternatively, an adhesive sheet or laminate can be obtained by coating the above adhesive composition onto a release sheet, drying it, bonding a substrate to the adhesive layer on the opposite side, and curing it as necessary.

[0150] Furthermore, by forming an adhesive layer on a release sheet and bonding the release sheet to the adhesive layer on the opposite side, a substrate-less double-sided adhesive sheet can be manufactured.

[0151] When using the resulting adhesive sheet or substrate-less double-sided adhesive sheet, the release sheet is peeled off from the adhesive layer and the adhesive layer is bonded to the adherend.

[0152] Examples of the above-mentioned substrates include polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate copolymer, etc. Polyester resins; Polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; Polyfluoroethylene resins such as polyvinyl fluoride, polyvinylidene fluoride, and polyfluoroethylene; Polyamides such as nylon 6 and nylon 6,6; Vinyl polymers such as polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and vinylon; Cellulose resins such as cellulose triacetate and cellophane; Polymethyl methacrylate, polymethacrylic acid Examples of substrates include sheets made from at least one synthetic resin selected from the group consisting of acrylic resins such as ethyl, ethyl polyacrylate, and butyl polyacrylate; polystyrene; polycarbonate; polyarylate; polyimide; and cycloolefin polymers; as well as metal foils of aluminum, copper, and iron; as well as paper such as fine paper and glassine paper; and as woven or nonwoven fabrics made of glass fibers, natural fibers, synthetic fibers, etc. These substrates can be used as single layers or as multilayered structures made by laminating two or more types.

[0153] Among these, substrates made of polyethylene terephthalate and polyimide are particularly preferred, and polyethylene terephthalate is especially preferred because of its excellent adhesion to adhesives.

[0154] Furthermore, as the substrate, it is preferable to use a film having a dielectric loss tangent of 0.01 or less at a frequency of 10 GHz under a temperature of 23°C and a relative humidity of 50% RH, as this can reduce transmission loss by lowering the overall dielectric loss tangent of the adhesive sheet or laminate. More preferably, it is 0.005 or less, and particularly preferably 0.003 or less. Specifically, examples include thermoplastic liquid crystal polymer films and low-dielectric polyimide films.

[0155] Furthermore, as the base material, a foam base material, such as a foamed sheet made of a synthetic resin foam like polyurethane foam, polyethylene foam, or polyacrylate foam, can be used. Among these, polyethylene foam and polyacrylate foam are preferred because they offer an excellent balance between conformability to the adherend and adhesive strength.

[0156] The thickness of the above-mentioned substrate is preferably, for example, 1 to 1000 μm, particularly preferably 2 to 500 μm, and even more preferably 3 to 300 μm.

[0157] As the release sheet mentioned above, for example, a sheet made of various synthetic resins as exemplified in the base material, paper, cloth, nonwoven fabric, etc., that has been treated with a release agent can be used. It is preferable to use a silicone-based release sheet.

[0158] For example, a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, comma coater, etc., may be used as the coating method for the above adhesive composition.

[0159] The conditions for the curing treatment described above are typically a temperature of room temperature (23°C) to 70°C, and a duration of typically 1 to 30 days. Specifically, for example, the treatment can be carried out at 23°C for 1 to 20 days, preferably at 23°C for 3 to 14 days, or at 40°C for 1 to 10 days.

[0160] Furthermore, as for drying conditions, the drying temperature is preferably 60 to 140°C, particularly preferably 80 to 120°C, and the drying time is preferably 0.5 to 30 minutes, particularly preferably 1 to 5 minutes.

[0161] The thickness of the adhesive layer is preferably 2 to 500 μm, particularly preferably 5 to 200 μm, and even more preferably 10 to 100 μm. If the adhesive layer is too thin, the adhesive strength tends to decrease, and if it is too thick, it becomes difficult to apply uniformly, and defects such as air bubbles in the coating film tend to occur. When considering shock absorption, it is preferable to have a thickness of 50 μm or more.

[0162] The thickness of the adhesive layer is determined by subtracting the measured thickness of the components other than the adhesive layer from the measured thickness of the entire adhesive sheet using the Mitutoyo ID-C112B.

[0163] Furthermore, such adhesive sheets may be protected by providing a release sheet on the outside of the adhesive layer, if necessary. In addition, in adhesive sheets where the adhesive layer is formed on one side of the substrate, it is also possible to protect the adhesive layer by applying a release treatment to the side of the substrate opposite to the adhesive layer, and utilizing the released surface.

[0164] The adhesives, bonding agents, and adhesive sheets of the present invention can be used for bonding various components, and are particularly suitable for bonding optical components, fixing components in portable electronic devices, and fixing electronic components. Preferably, when combined with a low-dielectric film having a dielectric loss tangent of 0.01 or less, they can be suitably used, for example, for bonding transparent antenna films for millimeter-wave or similar high-frequency radio waves, or for bonding radio wave reflective films.

[0165] Furthermore, while the sheet of the present invention is preferably used as an adhesive sheet as described above, it can also be used as a bonding sheet. Specifically, a bonding sheet is one which is prepared by coating a substrate with the present composition to form an adhesive layer, drying it to remove the solvent as necessary, and then attaching it directly to the object to be adhered to. [Examples]

[0166] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. In the examples, "parts" and "%" refer to weight basis.

[0167] <Example 1> [Manufacturing of polyester resin (A-1)] In a reaction vessel equipped with a thermometer, stirrer, rectification column, and nitrogen inlet tube, 72 parts (1.00 mol) of isophthalic acid (a1-1) as polycarboxylic acid (a1), 26.9 parts (1.00 mol) of ethylene glycol as polyhydric alcohol (a2), 897.0 parts (0.90 mol) of hydrogenated polybutadiene diol (a2-1) with a number average molecular weight of 2300 [GI-2000 (manufactured by Nippon Soda Co., Ltd.)], 4 parts (0.07 mol) of trimethylolpropane, and 0.1 part of tetrabutyl titanate as a catalyst were charged. The temperature was raised over 2.5 hours until the internal temperature reached 270°C, and the esterification reaction was carried out at 270°C for 1.5 hours. Next, 0.1 parts of tetrabutyl titanate were added as a catalyst, the system was reduced to 2.5 hPa, and the polymerization reaction was carried out over 2 hours to obtain a polyester resin (A-1) [adhesive composition of Example 1]. The final composition ratio was as shown in Table 1 below.

[0168] <Examples 2-4> [Manufacturing of polyester resins (A-2) to (A-4)] Following Example 1, polyester resins (A-2) to (A-4) [adhesive compositions of Examples 2 to 4] were manufactured in the same manner as polyester resin (A-1), except that the resin composition was changed to match that shown in Table 1 below.

[0169] <Comparative Examples 1-5> [Manufacturing of polyester resins (A'-1) to (A'-5)] Polyester resins (A'-1) to (A'-5) [adhesive compositions of Comparative Examples 1 to 5] were obtained in the same manner as polyester resin (A-1), except that the resin composition was changed to match that shown in Table 1 below.

[0170] The compositions listed in Table 1 below represent the final composition ratios (resin composition ratios), and are the relative ratios (molar ratios) of the amounts of each constituent monomer in the obtained polyester resin. The abbreviations used in Table 1 are as follows: "IPA": Isophthalic acid (a1-1) "DMI": Dimethyl isophthalate (a1-1) "DMT": Dimethyl terephthalate (a1-1) "TMAn": Trimellitus anhydride (a1-1) "AdA": Adipic acid "SebA": Sebacic acid "GI2000": Hydrogenated polybutadiene diol with hydroxyl groups at both ends (manufactured by Nippon Soda Co., Ltd., Mn2300) (a2-1) "GI3000": Hydrogenated polybutadiene diol with hydroxyl groups at both ends (manufactured by Nippon Soda Co., Ltd., Mn3000) (a2-1) "Prepol 2033": Hydrogenated dimer ol (manufactured by Croda, molecular weight 538) "EG": Ethylene glycol "1,4BG": 1,4-butanediol "NPG": Neopentyl Glycol "1,6HG": 1,6-Hexanediol "TMP": Trimethylolpropane

[0171] The glass transition temperature (°C), hydroxyl value (mgKOH / g), acid value (mgKOH / g), peak-top molecular weight (Mp), weight-average molecular weight (Mw), ester group concentration (millimoles / g), and dielectric loss tangent of the obtained polyester resin were measured according to the specifications. The dielectric loss tangent was also evaluated using the following evaluation criteria. The various properties of the polyester resin are shown in Table 2 below.

[0172] (Evaluation criteria for dielectric loss tangent) ◎: Below 0.0020 〇: Greater than 0.0020 and less than or equal to 0.0040 △: Greater than 0.0040 and less than or equal to 0.0100 ×: Exceeds 0.0100

[0173] [Table 1]

[0174] [Table 2]

[0175] From the results in Table 2 above, the polyester resins of Examples 1 to 4, which contain large amounts of aromatic polycarboxylic acids and hydrogenated polybutadiene diol, had a dielectric loss tangent of 0.004 or less. Furthermore, Examples 1, 3, and 4, which do not contain aliphatic polycarboxylic acids, had a dielectric loss tangent of 0.002 or less, demonstrating very good dielectric properties. On the other hand, the polyester resins of Comparative Examples 1 and 2, which contained a large amount of hydrogenated polybutadienediol but also a large amount of aliphatic polycarboxylic acid, had a dielectric loss tangent of 0.01 or higher. Furthermore, the polyester resin of Comparative Example 3, which contained aromatic polycarboxylic acids and dimergol, and the polyester resin of Comparative Example 5, in which some of the dimergol was replaced with hydrogenated polybutadienediol, showed a reasonably good dielectric loss tangent, but their dielectric properties were inferior to those of the polyester resins of Examples 1 to 4. In addition, Comparative Example 4, a typical polyester resin in which aliphatic polycarboxylic acids and aliphatic polyalcohols constitute a large portion of the polyester resin's composition, had very poor dielectric properties.

[0176] Next, the following were prepared as a crosslinking agent (B), a urethane catalyst (C), and a hindered phenol-based antioxidant.

[0177] <Crosslinking agent (B)> (B-1): Trimer of hexamethylene diisocyanate containing isocyanurate (manufactured by Tosoh Corporation, "Coronate HX") (B-2): Trimer of isophorone diisocyanate with isocyanurate (Evonik Degussa, "Vestanate T-1890") (B-3): 55% ethyl acetate solution of trimethylolpropane tolylene diisocyanate adduct (Tosoh Corporation, "Coronate L-55E")

[0178] <Urethane catalyst (C)> (C-1): Zirconium acetylacetonate (manufactured by Matsumoto Fine Chemical Co., Ltd., "ZC-150" diluted to 1% with acetylacetone.)

[0179] <Hindered phenol-based antioxidants> (D-1): IRGANOX1010 (BASF)

[0180] <Example 5> The polyester resin (A-1) obtained above was diluted with toluene to a solid content concentration of 50%. To this polyester resin (A-1) solution (as solid content), 1.5 parts of crosslinking agent (B-1) (solid content) were added. Furthermore, 0.02 parts of urethane catalyst (C-1) (active ingredient) and 0.1 parts of hindered phenol antioxidant (D-1) were added. The mixture was then diluted with toluene until the total solid content reached 50%, stirred, and mixed to obtain the adhesive composition of Example 5.

[0181] <Examples 6-10, Comparative Examples 6-10> Examples 6-10 and Comparative Examples 6-10 were obtained in the same manner as in Example 5, except that the components were blended as shown in Table 3 below.

[0182] The adhesive compositions obtained in Examples 5-10 and Comparative Examples 6-10 were applied to polyethylene terephthalate (PET) films (38 μm thick) so that the thickness after drying was approximately 25 μm and 50 μm, respectively. The films were then dried at 100°C for 3 minutes to form an adhesive layer. Subsequently, a release-treated PET film (release film) was attached to the adhesive layer to protect its surface, and the film was cured in an atmosphere at 40°C for 20 days to obtain an adhesive sheet.

[0183] The obtained adhesive sheets were evaluated as follows. The evaluation results are shown in Table 3 below.

[0184] [Gel fraction] The cured adhesive sheet obtained as described above was cut into 4cm x 4cm pieces. These were wrapped in 200-mesh stainless steel wire mesh and immersed in toluene at 23°C for 24 hours. The gel fraction was defined as the weight percentage of the insoluble adhesive component remaining in the wire mesh relative to the weight of the adhesive before immersion.

[0185] [Adhesive strength (peel strength) (compared to SUS-BA)] A SUS-BA plate was prepared as the adherend. The adhesive sheet obtained above was cut to 25 mm x 200 mm in an environment of 23°C and 50% RH. After peeling off the release film, the adhesive layer side was brought into contact with the SUS-BA plate, and pressure was applied by moving a 2 kg roller back and forth. After standing in the same environment for a predetermined time (30 minutes or 24 hours), the 180-degree peel strength (N / 25 mm) was measured at a peeling speed of 300 mm / min using an Autograph (Shimadzu Corporation, Autograph AGS-H 500N).

[0186] [Adhesion (Peel Strength) (against Glass)] Alkali-free glass plates were prepared as the substrate. The adhesive sheets obtained above were cut to 25 mm x 200 mm in an environment of 23°C and 50% RH. The release film was peeled off, and the adhesive layer side was brought into contact with the alkali-free glass plate. A 2 kg roller was then used to press and adhere the sheets by moving it back and forth. After standing for a predetermined time (30 minutes) in the same environment, the 180-degree peel strength (N / 25 mm) was measured at a peeling speed of 300 mm / min using an Autograph (Shimadzu Corporation, Autograph AGS-H 500N).

[0187] [Adhesive strength (peel strength) (against PP)] A polypropylene (PP) sheet was prepared as the substrate. The adhesive sheet obtained above was cut to 25 mm x 200 mm in an environment of 23°C and 50% RH. The release film was peeled off, the adhesive layer side was brought into contact with the PP sheet, and pressure was applied by moving a 2 kg roller back and forth. After standing for a predetermined time (30 minutes) in the same environment, the 180-degree peel strength (N / 25 mm) was measured at a peeling speed of 300 mm / min using an Autograph (Shimadzu Corporation, Autograph AGS-H 500N).

[0188] [Holding force (cohesive force)] The adhesive sheets obtained above were applied to SUS304 stainless steel as the substrate in accordance with JIS Z-0237, covering an area of ​​25 mm x 25 mm. After being left standing at 80°C for 20 minutes, a 1 kg load was applied, and the time until the sheets fell, or for those that did not fall after 24 hours, the displacement after 24 hours was measured in an 80°C environment and evaluated according to the following criteria. (Evaluation Criteria) ○...After standing for 24 hours, the displacement was within 1 mm. △...Although it did not fall after being left undisturbed for 24 hours, the displacement exceeded 1 mm. ×...It fell while left undisturbed for 24 hours.

[0189] [Dielectric properties] The dielectric properties (dielectric loss tangent Df) of the adhesive layer of the obtained 50 μm thick adhesive sheet were measured using the cavity resonator perturbation method with a network analyzer. The dielectric loss tangent Df was evaluated according to the following evaluation criteria. (Evaluation Criteria) ◎: Df is 0.0015 or less 〇: Df is greater than 0.0015 and less than or equal to 0.0030. △: Df is greater than 0.0030 and less than or equal to 0.01 ×: Df exceeds 0.01

[0190] [Table 3]

[0191] As shown in Table 3 above, the adhesive sheets (Examples 5-10) using polyester resins (A-1) to (A-4) exhibited excellent adhesion to metal and glass substrates. They also demonstrated excellent holding power, making them effective adhesives. Furthermore, when the dielectric properties of the adhesive layer of these sheets were measured, the adhesive layer also showed excellent dielectric properties, particularly low dielectric loss tangent. Examples 5, 6, and 8-10, which did not contain aliphatic polycarboxylic acids in the polyester resin, showed particularly excellent dielectric loss tangent. In contrast, adhesive sheets using polyester resins (A'-2, 3, 5) (Comparative Examples 7, 8, 10) showed slightly inferior dielectric loss tangent compared to the examples, while adhesive sheets using polyester resins (A'-1, 4) (Comparative Examples 6, 9) showed significantly inferior dielectric loss tangent. [Industrial applicability]

[0192] This composition is an adhesive composition containing a polyester resin, and it has a low dielectric constant and low dielectric loss tangent, particularly a low dielectric loss tangent, forming an adhesive with excellent adhesive properties. In particular, such an adhesive composition is effective as an adhesive used in electronic equipment that transmits and receives high-frequency signals.

Claims

1. An adhesive composition containing a polyester resin (A) having structural sites derived from polycarboxylic acids (a1) and structural sites derived from polyhydric alcohols (a2), In the structural site derived from the above polycarboxylic acid (a1), the content of the structural site derived from aromatic polycarboxylic acid (a1-1) is 20 mol% or more. In the structural site derived from the above polyhydric alcohols (a2), the content of the structural site derived from polydienediol and / or hydrogenated polydienediol (a2-1) is 20 mol% or more. An adhesive composition characterized in that the total amount of structural sites derived from the above aromatic polycarboxylic acids (a1-1) and structural sites derived from polydienediol and / or hydrogenated polydienediol (a2-1) in the polyester resin (A) is 90% by weight or more.

2. An adhesive composition containing a polyester resin (A) having structural sites derived from polycarboxylic acids (a1) and structural sites derived from polyhydric alcohols (a2), In the structural site derived from the above polycarboxylic acid (a1), the content of the structural site derived from aromatic polycarboxylic acid (a1-1) is 20 mol% or more. An adhesive composition characterized in that, in the structural site derived from the above polyhydric alcohol (a2), the content of the structural site derived from polydienediol and / or hydrogenated polydienediol (a2-1) is 70 mol% or more.

3. The adhesive composition according to claim 2, characterized in that the total amount of structural sites derived from the above aromatic polycarboxylic acids (a1-1) and structural sites derived from polydienediol and / or hydrogenated polydienediol (a2-1) in the polyester resin (A) is 90% by weight or more.

4. The adhesive composition according to claim 1 or 2, characterized in that the total amount of structural sites derived from the above aromatic polycarboxylic acids (a1-1) and structural sites derived from polydienediol and / or hydrogenated polydienediol (a2-1) in the polyester resin (A) is 95% by weight or more.

5. The adhesive composition according to claim 1 or 2, characterized in that the number average molecular weight of the polydienediol and / or hydrogenated polydienediol (a2-1) is 500 to 10000.

6. The adhesive composition according to claim 1 or 2, characterized in that the polydienediol and / or hydrogenated polydienediol (a2-1) is a polydienediol formed from a conjugated diene having 4 to 9 carbon atoms and / or a hydrogenated polydienediol formed from a conjugated diene having 4 to 9 carbon atoms.

7. The adhesive composition according to claim 1 or 2, characterized in that the dielectric loss tangent of the polyester resin (A) at a frequency of 10 GHz under a temperature of 23°C and a relative humidity of 50% RH is 0.01 or less.

8. The adhesive composition according to claim 1 or 2, characterized in that the acid value of the polyester resin (A) is 10 mg KOH / g or less.

9. The adhesive composition according to claim 1 or 2, further characterized by containing a crosslinking agent (B).

10. An adhesive characterized by being a crosslinked adhesive composition according to claim 1 or 2.

11. An adhesive sheet comprising an adhesive layer in which an adhesive composition containing a polyester resin (A) having structural sites derived from polycarboxylic acids (a1) and structural sites derived from polyhydric alcohols (a2) and a crosslinking agent (B) is crosslinked, and a release sheet on one side of the adhesive layer and a substrate on the other side, In the structural site derived from the above polycarboxylic acid (a1), the content of the structural site derived from aromatic polycarboxylic acid (a1-1) is 20 mol% or more. In the structural site derived from the above polyhydric alcohols (a2), the content of the structural site derived from polydienediol and / or hydrogenated polydienediol (a2-1) is 20 mol% or more. The dielectric loss tangent of the above adhesive layer at a frequency of 10 GHz under conditions of 23°C and 50% relative humidity is 0.01 or less. An adhesive sheet characterized in that the dielectric loss tangent at a frequency of 10 GHz under the above substrate conditions of a temperature of 23°C and a relative humidity of 50% RH is 0.01 or less.

12. A laminate comprising a crosslinked adhesive layer containing a polyester resin (A) having structural sites derived from polycarboxylic acids (a1) and structural sites derived from polyhydric alcohols (a2), and a crosslinking agent (B), and a substrate on at least one surface of the adhesive layer, In the structural site derived from the above polycarboxylic acid (a1), the content of the structural site derived from aromatic polycarboxylic acid (a1-1) is 20 mol% or more. In the structural site derived from the above polyhydric alcohols (a2), the content of the structural site derived from polydienediol and / or hydrogenated polydienediol (a2-1) is 20 mol% or more. The dielectric loss tangent of the above adhesive layer at a frequency of 10 GHz under conditions of 23°C and 50% relative humidity is 0.01 or less. A laminate characterized in that the dielectric loss tangent of the above-mentioned substrate at a frequency of 10 GHz under conditions of a temperature of 23°C and a relative humidity of 50% RH is 0.01 or less.

13. An adhesive composition containing a polyester resin (A) having structural sites derived from polycarboxylic acids (a1) and structural sites derived from polyhydric alcohols (a2), In the structural site derived from the above polycarboxylic acid (a1), the content of the structural site derived from aromatic polycarboxylic acid (a1-1) is 20 mol% or more. In the structural site derived from the above polyhydric alcohols (a2), the content of the structural site derived from polydienediol and / or hydrogenated polydienediol (a2-1) is 20 mol% or more. An adhesive composition characterized in that the total amount of structural sites derived from the above aromatic polycarboxylic acids (a1-1) and structural sites derived from polydienediol and / or hydrogenated polydienediol (a2-1) in the polyester resin (A) is 90% by weight or more.

14. The adhesive composition according to claim 13, characterized in that the total amount of structural sites derived from the above aromatic polycarboxylic acids (a1-1) and structural sites derived from polydienediol and / or hydrogenated polydienediol (a2-1) in the polyester resin (A) is 95% by weight or more.

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