(METH)acrylic resin, curable composition, and multilayer sheet

Abstract

A purpose of the present invention is to provide a (meth)acrylic resin capable of forming a release layer which has improved releasing properties while retaining wettability by coating fluids. This (meth)acrylic resin includes a constituent unit represented by a specific structural formula. Since the (meth)acrylic resin includes the constituent unit represented by a specific structural formula and has an iodine value of 50 g-I2 / 100 g or less, a release layer having improved releasing properties while retaining wettability by coating fluids can be formed therefrom.

Description

(Meth)acrylic resin, curable composition, and multilayer sheet

[0001] The present invention relates to a (meth)acrylic resin, a curable composition, and a multilayer sheet.

[0002] Conventionally, release sheets having a substrate and a release layer have been known (for example, see Patent Document 1). The release sheet is produced by applying a release agent to the substrate and curing the agent to form the release layer.

[0003] Such release sheets are used in a variety of applications, such as protective sheets for protecting the adhesive surfaces of pressure-sensitive adhesive sheets and patches, and process films for producing multilayer ceramic electronic components, such as multilayer ceramic capacitors and multilayer ceramic substrates.

[0004] When the release sheet is used as a protective sheet, an adhesive layer is formed on the release layer of the release sheet by coating and drying an adhesive solution containing an adhesive and a solvent. When the release sheet is used as a processing film, a ceramic slurry is first coated on the release layer of the release sheet and dried to form a ceramic green sheet. The ceramic slurry contains ceramic components, a binder resin, a solvent, and the like. Next, electrodes having a desired pattern are printed on the ceramic green sheet, and the release sheet is then peeled off from the ceramic green sheet. The ceramic green sheets are then stacked, pressed, and fired, and external electrodes are provided to obtain a multilayer ceramic electronic component.

[0005] International Publication No. 2020-129962

[0006] As described above, a coating layer such as a pressure-sensitive adhesive layer or a ceramic green sheet is formed on the release layer of a release sheet. However, conventional release sheets have a problem in that the release layer has low releasability. When the release layer has low releasability, it becomes difficult to peel the coating layer from the release layer.

[0007] However, attempts to improve the release properties of the release layer may result in a decrease in the wettability of the release layer. When forming a coating layer, a coating liquid such as an adhesive solution or a ceramic slurry is applied to the release layer of a release sheet, as described above. If the wettability of the release layer is low, the coating liquid will repel on the surface of the release layer, resulting in holes and recesses in the coating layer. This makes it difficult to form a coating layer with a uniform thickness on the release layer. In particular, in recent years, coating layers have become thinner. Therefore, it is necessary to apply the coating liquid to a thinner coating thickness on the release layer. However, the thinner the coating thickness, the more likely the coating liquid will repel. Therefore, it is necessary to improve the release properties of the release layer while maintaining the wettability of the release layer to the coating liquid.

[0008] An object of the present invention is to provide a (meth)acrylic resin capable of forming a release layer having improved releasability from a coating layer while maintaining wettability with a coating liquid. A further object of the present invention is to provide a curable composition and a multilayer sheet containing the (meth)acrylic resin.

[0009] The present invention has the following embodiment: A (meth)acrylic resin containing a structural unit represented by the following formula (A), wherein the structural unit represented by formula (A) includes a structural unit represented by the following formula (A1), and the (meth)acrylic resin has an iodine value of 50 gI / 100 g or less.

[0010] In the (meth)acrylic resin, the content of the (meth)acrylic resin containing a structural unit represented by the following formula (A), which contains a structural unit represented by the following formula (A1) as the structural unit represented by the formula (A) and has an iodine value of 50 gI / 100 g or less, is preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, more preferably 98% by mass or more, more preferably 99% by mass or more, and more preferably 100% by mass.

[0011] [1] A (meth)acrylic resin containing a structural unit represented by the following formula (A): The (meth)acrylic resin contains a structural unit represented by the following formula (A1) as the structural unit represented by the following formula (A), and has an iodine value of 50 gI / 100 g or less. (In the above formula (A), R 1 represents a hydrogen atom or a methyl group, and X represents a monovalent organic group containing two or more carbon atoms. (In the above formula (A1), R 1 represents a hydrogen atom or a methyl group, R 2 represents a divalent organic group having a hydroxyl group, R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

[0012] [2] A curable composition comprising the (meth)acrylic resin and a curing agent.

[0013] [3] A multilayer sheet comprising a substrate and a layer that is a cured product of the curable composition.

[0014] Here, "(meth)acrylic resin" means an acrylic resin or a methacrylic resin. "(meth)acrylic acid" means an acrylic acid or a methacrylic acid. "(meth)acrylate" means an acrylate or a methacrylate. "(meth)acrylic monomer" means an acrylic monomer or a methacrylic monomer.

[0015] According to the present invention, it is possible to provide a (meth)acrylic resin that can form a release layer having improved releasability while maintaining wettability with a coating liquid.

[0016] In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example. In this specification, a numerical value connected with "to" means a numerical range that includes the numbers before and after "to" as the lower and upper limits.

[0017] <(Meth)acrylic Resin> The (meth)acrylic resin of the present invention contains a structural unit represented by the following formula (A): The (meth)acrylic resin contains a structural unit represented by the following formula (A1) as the structural unit represented by the following formula (A), and has an iodine value of 50 gI / 100 g or less.

[0018] (In the above formula (A), R 1 represents a hydrogen atom or a methyl group, and X represents a monovalent organic group containing two or more carbon atoms.

[0019] (In the above formula (A1), R 1 represents a hydrogen atom or a methyl group, R 2 represents a divalent organic group having a hydroxyl group, R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

[0020] The structural unit represented by the above formula (A1) has R 3 That is, in the constitutional unit represented by the above formula (A), X has a monovalent aliphatic hydrocarbon group at the side chain terminal. 3 Due to the high hydrophobicity of this aliphatic hydrocarbon group, the release layer formed from the (meth)acrylic resin can exhibit high releasability with respect to a coating layer formed on the release layer using a coating liquid.

[0021] The structural unit represented by the above formula (A1) is R 2 As the divalent organic group having a hydroxyl group, 2represents a monovalent aliphatic hydrocarbon group R located at the end of a side chain. 3 That is, in the constitutional unit represented by the above formula (A), X is arranged closer to the main chain than R 3 and R located between the main chain 2 By adopting such an arrangement structure, it becomes possible for the (meth)acrylic resin to maintain wettability with respect to the coating liquid while improving releasability with respect to the coating layer.

[0022] The (meth)acrylic resin preferably contains, as a structural unit, a structure represented by the following formula (F1) or (F2): In formulas (F1) and (F2), * represents a bond and represents a single bond.

[0023]

[0024] Furthermore, the iodine value of the (meth)acrylic resin is set to 50 gI / 100 g or less. Here, the iodine value of the (meth)acrylic resin can be used as an indicator of the amount of unsaturated bonds in the (meth)acrylic resin. The lower the iodine value of the (meth)acrylic resin, the lower the amount of unsaturated bonds in the (meth)acrylic resin. By setting the iodine value of the (meth)acrylic resin to 50 gI / 100 g or less, the releasability of the release layer formed by the (meth)acrylic resin can be improved.

[0025] Therefore, by using the structural unit represented by the above formula (A1) and setting the iodine value to 50 gI / 100 g or less, the release property of the coating layer formed on the release layer using a coating liquid is improved, while the wettability of the release layer to the coating liquid is maintained. In other words, by using the structural unit represented by the above formula (A1) and setting the iodine value to 50 gI / 100 g or less, it is possible to provide a (meth)acrylic resin that can form a release layer that achieves both of these contradictory properties.

[0026] The above mechanism by which the effects of the present invention are obtained is one that has been speculated by the present inventors, and therefore the present invention is not limited to the above mechanism.

[0027] In the following description of the (meth)acrylic resin, for ease of understanding, substituents or linking groups having the same structure are represented by the same symbol even in different structural units. When different structural units are contained in the (meth)acrylic resin, the substituents and linking groups represented by the same symbol between the different structural units may be the same or different.

[0028] [Structural Unit Represented by Formula (A)] The (meth)acrylic resin of the present invention contains a structural unit represented by the above formula (A).

[0029] The (meth)acrylic resin is preferably a polymer of a monomer containing a (meth)acrylic monomer. The (meth)acrylic monomer is an addition-polymerizable monomer containing an ethylenically unsaturated double bond in one molecule. Therefore, the structural unit represented by the above formula (A) is preferably a structural unit derived from a (meth)acrylic monomer.

[0030] In the above formula (A), X represents a monovalent organic group containing two or more carbon atoms. The monovalent organic group (X) means a monovalent group containing at least two carbon atoms. The monovalent organic group (X) is represented by R 1 It is preferable that the carbon atom constituting the carbonyl group (—CO—) in the ester bond (—CO—O—) is directly bonded to the carbon atom to which the group is directly bonded.

[0031] Specific examples of the structural unit represented by formula (A) above include structural units represented by formulas (A1) to (A4), (A1-a), (A1-b), (A1-a1) to (A1-a4), (A1-b1) to (A1-b5), and (A3-a) described below. In each of the structural units represented by formulas (A1) to (A4), (A1-a), (A1-b), (A1-a1) to (A1-a4), (A1-b1) to (A1-b5), and (A3-a) below, the residue excluding the structural portion represented by formula (A') below corresponds to the "monovalent organic group represented by X in formula (A)".

[0032] (In formula (A'), R 1 represents a hydrogen atom or a methyl group.

[0033] The content of the structural unit represented by the above formula (A) in the (meth)acrylic resin is preferably 50% by mass or more, more preferably 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, more preferably 98% by mass or more, and particularly preferably 100% by mass, relative to 100% by mass of the total amount of all structural units contained in the (meth)acrylic resin.

[0034] (Structural Unit Represented by Formula (A1)) The (meth)acrylic resin contains the structural unit represented by the formula (A1) as the structural unit represented by the formula (A). That is, in the (meth)acrylic resin, the structural unit represented by the formula (A) contains the structural unit represented by the formula (A1). When the (meth)acrylic resin contains the structural unit represented by the formula (A1), it becomes possible for the (meth)acrylic resin to form a release layer with improved releasability while maintaining wettability with respect to a coating liquid.

[0035] In the above formula (A1), R 2 represents a divalent organic group having a hydroxyl group. 2 ) means a divalent group containing at least one carbon atom and a hydroxyl group. 2 ) is R in the above formula (A1). 1 It is preferable that the carbon atom constituting the carbonyl group (—CO—) in the ester bond (—CO—O—) is directly bonded to the carbon atom to which the group is directly bonded.

[0036] In the above formula (A1), R 2 is R in the above formula (A1). 1 and a carbon atom (C) to which a group represented by the formula: 3 It is arranged between the group represented by R 3 is a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group. 3 is a monovalent atomic group consisting only of carbon and hydrogen atoms.

[0037] Therefore, in the above formula (A1), ≡C-R 2 -R 3In the side chain portion represented by the formula (I), a monovalent atomic group consisting of only carbon atoms and hydrogen atoms located at the terminal of this side chain portion is referred to as a "monovalent aliphatic hydrocarbon group (R 3 )) from the side chain portion to the monovalent aliphatic hydrocarbon group (R 3 ) and R 1 The remaining portion excluding the carbon atom (≡C) to which the group represented by 2 In the present invention, the "≡" in "≡C" means three single bonds.

[0038] Specifically, in each of the structural units represented by the following formula (A1-a) and the following formula (A1-b), the portion surrounded by the dashed line corresponds to R 2 This corresponds to a divalent organic group represented by the following formula:

[0039] In the above formula (A1), R 2 The number of carbon atoms and R 3 The total number of carbon atoms in R is preferably 6 or more. 2 The number of carbon atoms and R 3 and the number of carbon atoms is preferably 60 or less, more preferably 50 or less, more preferably 45 or less, and still more preferably 40 or less.

[0040] In the above formula (A1), R 3 R is a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group. 3 is preferably a linear or branched, saturated, monovalent aliphatic hydrocarbon group, and more preferably a linear, saturated, monovalent aliphatic hydrocarbon group.

[0041] In the above formula (A1), the monovalent aliphatic hydrocarbon group R 3 The number of carbon atoms in the monovalent aliphatic hydrocarbon group R is preferably 12 or more, more preferably 14 or more, and even more preferably 16 or more. 3 The number of carbon atoms is preferably 30 or less, and more preferably 25 or less.

[0042] In the above formula (A1), the monovalent aliphatic hydrocarbon group R 3Examples of the alkyl group include: linear saturated monovalent aliphatic hydrocarbon groups such as decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, heniicosyl, and docosyl; branched saturated monovalent aliphatic hydrocarbon groups such as isodecyl, isododecyl, isotetradecyl, isohexadecyl, and isooctadecyl; unsaturated monovalent aliphatic hydrocarbon groups having one double bond such as decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, and nonadecenyl; and Examples include unsaturated monovalent aliphatic hydrocarbon groups having two double bonds, such as a pentadecadienyl group, a hexadecadienyl group, a heptadecadienyl group, an octadecadienyl group, and a nonadecadienyl group.

[0043] As the linear saturated monovalent aliphatic hydrocarbon group, a pentadecyl group, a heptadecyl group, and a henicosyl group are preferred, with a heptadecyl group and a henicosyl group being more preferred. As the unsaturated monovalent aliphatic hydrocarbon group having one double bond, a heptadecenyl group is preferred. As the unsaturated monovalent aliphatic hydrocarbon group having two double bonds, a heptadecadienyl group is preferred. Of these, a heptadecyl group and a henicosyl group are preferred.

[0044] Specifically, the structural unit represented by the above formula (A1) is preferably at least one of a structural unit represented by the following formula (A1-a) and a structural unit represented by the following formula (A1-b). 2 is preferably a divalent organic group represented by the portion surrounded by a dashed line in each of the structural units represented by the following formula (A1-a) and the following formula (A1-b). These structural units enable the (meth)acrylic resin to form a release layer with improved releasability while maintaining wettability with respect to a coating liquid.

[0045] (In each of the above formula (A1-a) and the above formula (A1-b), R 1represents a hydrogen atom or a methyl group, R 4 represents a single bond or an alkylene group having 1 to 3 carbon atoms, R 5 represents a hydrogen atom or a methyl group, L represents a single bond or a divalent linking group, R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

[0046] R in each of the above formula (A1-a) and the above formula (A1-b) 4 represents a single bond or an alkylene group having 1 to 3 carbon atoms. Examples of alkylene groups having 1 to 3 carbon atoms include a methylene group [-CH2-], an ethylene group [-CH2-CH2-], and an n-propylene group [-CH2-CH2-CH2-]. R 4 is preferably a single bond or a methylene group, more preferably a methylene group. In the present invention, the alkylene group refers to a divalent atomic group generated by abstracting one hydrogen atom bonded to each different carbon atom in a saturated aliphatic hydrocarbon, or a divalent atomic group generated by abstracting two hydrogen atoms from methane, and includes both linear and branched atomic groups.

[0047] R in each of the above formula (A1-a) and the above formula (A1-b) 5 is a hydrogen atom or a methyl group, preferably a hydrogen atom.

[0048] In each of the above formulas (A1-a) and (A1-b), L represents a single bond or a divalent linking group. Examples of the divalent linking group include the groups shown below.

[0049]

[0050] In the (meth)acrylic resin, the structural unit represented by the above formula (A1) preferably includes at least one of the structural unit represented by the above formula (A1-a) and the structural unit represented by the above formula (A1-b), and more preferably includes both.

[0051] R in each of the above formula (A1-a) and the above formula (A1-b) 3 is the R3 Since it is the same as the above, detailed description will be omitted.

[0052] Examples of the structural unit represented by the above formula (A1) include a structural unit derived from a (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto. Note that, in this specification, for example, the monomer used to form the structural unit (A1) may also be referred to as monomer (A1).

[0053] Examples of the (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto include an addition reaction product (A1-1) of an epoxy group-containing (meth)acrylate and an aliphatic hydrocarbon compound (E1) having an epoxy-reactive group, and an addition reaction product (A1-2) of (meth)acrylic acid and an aliphatic hydrocarbon compound (E2) having an epoxy group or a glycidyloxy group.

[0054] The (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto is preferably the above-mentioned addition reaction product (A1-1) or (A1-2), and more preferably the above-mentioned addition reaction product (A1-1). First, the above-mentioned addition reaction product (A1-1) will be described below.

[0055] As described above, the (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto is preferably an addition reaction product (A1-1) of an epoxy group-containing (meth)acrylate and an aliphatic hydrocarbon compound (E1) having an epoxy-reactive group. Examples of the epoxy-reactive group include a carboxy group, a hydroxyl group, or a methylamino group. The aliphatic hydrocarbon compound (E1) preferably has a carboxy group, a hydroxyl group, or a methylamino group. These epoxy-reactive groups can undergo a ring-opening addition reaction with the epoxy group. Therefore, the ring-opening addition reaction between the epoxy group of the epoxy group-containing (meth)acrylate and the epoxy-reactive group of the aliphatic hydrocarbon compound (E1) results in an addition reaction product (A1-1) in which the aliphatic hydrocarbon group derived from the aliphatic hydrocarbon compound (E1) is added to the epoxy group-containing (meth)acrylate. This addition reaction product (A1-1) can be used as the (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto.

[0056] The epoxy group-containing (meth)acrylate preferably has one epoxy group per molecule. Examples of the epoxy group-containing (meth)acrylate include glycidyl (meth)acrylate and 2-methylglycidyl (meth)acrylate. The epoxy group-containing (meth)acrylate is preferably glycidyl (meth)acrylate, and more preferably glycidyl methacrylate. The epoxy group-containing (meth)acrylate may be used alone or in combination of two or more.

[0057] Specific examples of the aliphatic hydrocarbon compound (E1) having an epoxy-reactive group include compounds represented by the following formula (EI): E1 -R 3 (EI) (wherein, X E1 represents an epoxy-reactive group which is any one of a carboxy group, a hydroxyl group, and a methylamino group; R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

[0058] In the above formula (EI), R 3is the R 3 Since it is the same as the above, detailed description will be omitted.

[0059] The aliphatic hydrocarbon compound (E1) having a carboxy group as an epoxy-reactive group includes, for example, X E1 Compounds represented by the above formula (E-I) in which is a carboxy group include, for example, saturated fatty acids and unsaturated fatty acids. Examples of saturated fatty acids include octanoic acid (caprylic acid), nonanoic acid, decanoic acid (capric acid), dodecanoic acid (lauric acid), tetradecanoic acid (myristic acid), hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), octadecanoic acid (stearic acid), icosanoic acid (arachidic acid), docosanoic acid (behenic acid), and tetracosanoic acid. Examples of unsaturated fatty acids include oleic acid, linoleic acid, linolenic acid, icosenoic acid, and erucic acid. The aliphatic hydrocarbon compound (E1) having a carboxy group may be used alone or in combination of two or more.

[0060] The aliphatic hydrocarbon compound (E1) having a carboxy group as an epoxy-reactive group also includes fatty acids derived from animal fats and vegetable fats and oils. Examples of fatty acids derived from animal fats and oils include beef tallow fatty acids, lard fatty acids, fish oil fatty acids, and fatty acids obtained by hydrogenating (hardening) these fatty acids. Examples of fatty acids derived from vegetable fats and oils include tall oil fatty acids, soybean oil fatty acids, linseed oil fatty acids, tung oil fatty acids, coconut oil fatty acids, and castor oil fatty acids. Of the fatty acids derived from vegetable fats and oils, tall oil fatty acids are preferred.

[0061] The aliphatic hydrocarbon compound (E1) having a hydroxyl group as an epoxy reactive group includes, for example, X E1 Examples of the compound represented by the formula (EI) in which is a hydroxyl group include lauryl alcohol, myristyl alcohol, cetyl alcohol, oleyl alcohol, stearyl alcohol, behenyl alcohol, etc. The aliphatic hydrocarbon compound (E1) having a hydroxyl group may be used alone or in combination of two or more.

[0062] The epoxy-reactive group X of the above formula (EI) E1 The "methylamino group" in the above is a group represented by -NHCH3 (CH3 is directly bonded to the nitrogen atom).

[0063] The aliphatic hydrocarbon compound (E1) having a methylamino group as an epoxy-reactive group includes, for example, X E1 Examples of the compound represented by the formula (EI) in which is a methylamino group include N-methyllaurylamine, N-methylmyristylamine, N-methylcetylamine, N-methylstearylamine, N-methylbehenylamine, and N-methyldodecylamine. The aliphatic hydrocarbon compound (E1) having a methylamino group may be used alone or in combination of two or more.

[0064] The aliphatic hydrocarbon compound (E1) having an epoxy-reactive group is preferably an aliphatic hydrocarbon compound (E1) having a carboxy group, more preferably a saturated fatty acid, more preferably a linear saturated fatty acid, more preferably stearic acid, behenic acid, palmitic acid, lauric acid, and octanoic acid, more preferably stearic acid, behenic acid, palmitic acid, and lauric acid, more preferably stearic acid, behenic acid, and lauric acid, more preferably stearic acid and behenic acid, and more preferably behenic acid.

[0065] The content of the aliphatic hydrocarbon compound (E1) having a carboxy group in the aliphatic hydrocarbon compound (E1) having an epoxy-reactive group is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 85% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.

[0066] The content of saturated fatty acids in the aliphatic hydrocarbon compound (E1) having a carboxy group is preferably 35% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 85% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.

[0067] Among the structural units represented by formula (A1), the content of structural units derived from an addition reaction product (A1-1) of an epoxy group-containing (meth)acrylate and a saturated fatty acid is preferably 35 mol% or more, more preferably 45 mol% or more, more preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 85 mol% or more, more preferably 95 mol% or more, and particularly preferably 100 mol%.

[0068] Among the structural units represented by formula (A1), the content of structural units derived from an addition reaction product (A1-1) of an epoxy group-containing (meth)acrylate and a saturated fatty acid is preferably 35% by mass or more, more preferably 45% by mass or more, more preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 85% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.

[0069] The epoxy-reactive group of the aliphatic hydrocarbon compound (E1) can undergo a ring-opening addition reaction with the epoxy group of the epoxy-group-containing (meth)acrylate. The ring-opening addition reaction between the epoxy group of the epoxy-group-containing (meth)acrylate and the epoxy-reactive group of the aliphatic hydrocarbon compound (E1) can add the aliphatic hydrocarbon compound (E1) to the epoxy-group-containing (meth)acrylate. This allows the production of a (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group derived from the aliphatic hydrocarbon compound (E1) added thereto.

[0070] One embodiment of the ring-opening addition reaction between an epoxy group-containing (meth)acrylate and an aliphatic hydrocarbon compound (E1) having an epoxy-reactive group is shown in the following reaction formulas (I) to (III): When the epoxy-reactive group of the aliphatic hydrocarbon compound (E1) is a "carboxy group," a "hydroxyl group," or a "methylamino group," the ring-opening addition reaction occurs as shown in the following reaction formula (I), (II), or (III), respectively.

[0071] (In reaction formulas (I) to (III), Q represents a residue obtained by removing the epoxy group from the epoxy group-containing (meth)acrylate, and R 3represents a residue of the aliphatic hydrocarbon compound (E1) excluding the epoxy-reactive group, i.e., a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

[0072] The (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto may also be an addition reaction product (A1-2) of (meth)acrylic acid and an aliphatic hydrocarbon compound (E2) having an epoxy group or a glycidyloxy group.

[0073] (Meth)acrylic acid is a compound having a carboxy group. The aliphatic hydrocarbon compound (E2) has an epoxy group or a glycidyloxy group (2,3-epoxypropoxy group). Therefore, all of the aliphatic hydrocarbon compounds (E2) have an epoxy group.

[0074] The carboxy group of (meth)acrylic acid and the epoxy group of the aliphatic hydrocarbon compound (E2) undergo a ring-opening addition reaction to obtain an addition reaction product (A1-2) in which an aliphatic hydrocarbon group derived from the aliphatic hydrocarbon compound (E2) is added to (meth)acrylic acid. This addition reaction product (A1-2) can be used as the (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto.

[0075] Specific examples of the aliphatic hydrocarbon compound (E2) having an epoxy group or a glycidyloxy group include compounds represented by the following formula (E-II): E2 -R 3 (E-II) (wherein, X E2 represents an epoxy group or a glycidyloxy group, and R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

[0076] In the above formula (E-II), R 3 is the R 3 Since it is the same as the above, detailed description will be omitted.

[0077] As the aliphatic hydrocarbon compound (E2) having an epoxy group, that is, X E2is an epoxy group, specific examples of the compound represented by formula (E-II) include 1,2-epoxyalkanes. Examples of 1,2-epoxyalkanes include 1,2-epoxyoctane, 1,2-epoxydecane, 1,2-epoxydodecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane, and 1,2-epoxyoctadecane. The aliphatic hydrocarbon compound (E2) having an epoxy group may be used alone or in combination of two or more.

[0078] As the aliphatic hydrocarbon compound (E2) having a glycidyloxy group, that is, X E2 is a glycidyloxy group, specific examples of the compound represented by formula (E-II) include alkyl glycidyl ethers. Examples of alkyl glycidyl ethers include octyl glycidyl ether, decyl glycidyl ether, dodecyl glycidyl ether, tetradecyl glycidyl ether, hexadecyl glycidyl ether, and octadecyl glycidyl ether. The aliphatic hydrocarbon compound (E2) having a glycidyloxy group may be used alone or in combination of two or more.

[0079] One embodiment of the ring-opening addition reaction between (meth)acrylic acid and an aliphatic hydrocarbon compound (E2) having an epoxy group or a glycidyloxy group is shown in the following reaction formulas (IV) and (V).

[0080] When an aliphatic hydrocarbon compound (E2) having an epoxy group or an aliphatic hydrocarbon compound (E2) having a glycidyloxy group is used, the ring-opening addition reaction occurs as shown in the following reaction formula (IV) or (V), respectively.

[0081] In each of the reaction formulas (IV) and (V), A represents a residue obtained by removing the carboxy group from (meth)acrylic acid, and R 3 represents a residue obtained by removing the epoxy group from the aliphatic hydrocarbon compound (E2), and R 3 represents the residue of the aliphatic hydrocarbon compound (E2) excluding the glycidyloxy group. That is, R3 each represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

[0082] The (meth)acrylic resin preferably has, as the structural unit represented by the above formula (A1), a structural unit derived from the above-mentioned (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto. Specific examples of the structural unit derived from this (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto, that is, specific examples of the above formula (A1-a) and formula (A1-b), include at least one of the structural units represented by the following formulas (A1-a1) to (A1-a4) and (A1-b1) to (A1-b5):

[0083]

[0084]

[0085]

[0086] (In each of the above formulae (A1-a1) to (A1-a4) and (A1-b1) to (A1-b5), R 1 represents a hydrogen atom or a methyl group, R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

[0087] In addition, in each of the above formulas (A1-a1) to (A1-a4) and (A1-b1) to (A1-b5), R 3 is the R 3 Since it is the same as the above, detailed description will be omitted.

[0088] For example, when glycidyl (meth)acrylate and an aliphatic hydrocarbon compound (E1) having a carboxy group are used, examples of the structural units derived from the addition reaction product (A1-1) thereof include the structural units represented by the above formula (A1-a1) and the above formula (A1-b1).

[0089] For example, when glycidyl (meth)acrylate and an aliphatic hydrocarbon compound (E1) having a hydroxyl group are used, examples of the structural units derived from the addition reaction product (A1-1) thereof include the structural units represented by the above formula (A1-a2) and the above formula (A1-b2).

[0090] For example, when glycidyl (meth)acrylate and an aliphatic hydrocarbon compound (E1) having a methylamino group are used, examples of the structural units derived from the addition reaction product (A1-1) thereof include the structural units represented by the above formula (A1-a3) and the above formula (A1-b3).

[0091] For example, when (meth)acrylic acid and an aliphatic hydrocarbon compound (E2) having an epoxy group are used, examples of the structural units derived from the addition reaction product (A1-2) thereof include the structural units represented by the above formula (A1-a4) and the above formula (A1-b4).

[0092] For example, when (meth)acrylic acid and an aliphatic hydrocarbon compound (E2) having a glycidyloxy group are used, examples of the structural units derived from the addition reaction product (A1-2) thereof include the structural units represented by the above formula (A1-a2) and the above formula (A1-b5).

[0093] In the (meth)acrylic resin, the structural unit represented by the above formula (A1) may include only one type of structural unit, or two or more types of structural units, among the structural units represented by the above formulae (A1-a1) to (A1-a4) and (A1-b1) to (A1-b5).

[0094] In the (meth)acrylic resin, the structural unit represented by the above formula (A1) is preferably a structural unit represented by the above formula (A1-1), and more preferably a structural unit represented by the above formula (A1-a1) or (A1-b1).

[0095] In the (meth)acrylic resin, the content of the structural unit represented by formula (A1) is preferably 1.0 mol% or more, more preferably 5.0 mol% or more, more preferably 10.0 mol% or more, more preferably 25.0 mol% or more, more preferably 35.0 mol% or more, more preferably 45.0 mol% or more, more preferably 50.0 mol% or more, more preferably 70.0 mol% or more, more preferably 90.0 mol% or more, more preferably 99.0 mol% or more, and particularly preferably 100 mol% relative to the total amount of the structural units represented by formula (A) (100 mol%). By making the content of the structural unit represented by formula (A1) 1.0 mol% or more, the releasability of the release layer can be improved.

[0096] In the (meth)acrylic resin, the content of the structural unit represented by the above formula (A1) is preferably 1.0% by mass or more, more preferably 5.0% by mass or more, more preferably 15.0% by mass or more, more preferably 25.0% by mass or more, more preferably 35.0% by mass or more, more preferably 45.0% by mass or more, more preferably 55.0% by mass or more, more preferably 65.0% by mass or more, more preferably 75.0% by mass or more, more preferably 85.0% by mass or more, more preferably 95.0% by mass or more, and more preferably 100% by mass, relative to the total amount (100% by mass) of the structural units represented by formula (A1). By making the content of the structural unit represented by formula (A1) 1.0% by mass or more, the releasability of the release layer can be improved.

[0097] The (meth)acrylic resin may contain only one type of structural unit represented by the above formula (A), or may contain two or more types. When the (meth)acrylic resin contains only one type of structural unit represented by the above formula (A), it is preferable that the (meth)acrylic resin contains only the structural unit represented by the above formula (A1) as the structural unit represented by the above formula (A). It is preferable that the (meth)acrylic resin contains two or more types of structural units represented by the above formula (A).

[0098] (Structural Unit Represented by Formula (A2)) The (meth)acrylic resin can further contain a structural unit represented by the following formula (A2) as the structural unit represented by formula (A). That is, in the (meth)acrylic resin, the structural unit represented by the above formula (A) can contain the structural unit represented by the above formula (A1) and the structural unit represented by the following formula (A2).

[0099] (In the above formula (A2), R 1 represents a hydrogen atom or a methyl group, R 6 represents a linear or branched, saturated monovalent aliphatic hydrocarbon group.

[0100] In the above formula (A2), R 6 The monovalent aliphatic hydrocarbon group represented by the formula (I) is a so-called alkyl group. 6 The number of carbon atoms in the monovalent aliphatic hydrocarbon group R is preferably 5 or more, and more preferably 7 or more. 6 The number of carbon atoms in the monovalent aliphatic hydrocarbon group R is preferably 30 or less, and more preferably 25 or less. 6 When the number of carbon atoms is within the above range, the release properties of the release layer can be improved.

[0101] In the above formula (A2), R 6 Examples of the monovalent aliphatic hydrocarbon group represented by the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a lauryl group, a myristyl group, a palmityl group, a stearyl group, and a behenyl group. An octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a lauryl group, a myristyl group, a palmityl group, a stearyl group, and a behenyl group are preferred, and a 2-ethylhexyl group, a stearyl group, and a behenyl group are more preferred.

[0102] The structural unit represented by the above formula (A2) is preferably a structural unit derived from an alkyl(meth)acrylate (A2). 6This corresponds to a monovalent aliphatic hydrocarbon group represented by the following formula:

[0103] Examples of the alkyl (meth)acrylate (A2) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate.

[0104] Among these, as the alkyl (meth)acrylate (A2), octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate are preferred, and 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate are more preferred.

[0105] In the (meth)acrylic resin, the content of the structural unit represented by formula (A2) is preferably 99.0 mol% or less, more preferably 95.0 mol% or less, more preferably 85.0 mol% or less, more preferably 75.0 mol% or less, more preferably 65.0 mol% or less, more preferably 55.0 mol% or less, more preferably 45.0 mol% or less, more preferably 40.0 mol% or less, more preferably 25.0 mol% or less, more preferably 15.0 mol% or less, more preferably 10.0 mol% or less, more preferably 5.0 mol% or less, more preferably 3.0 mol% or less, more preferably 1.0 mol% or less, particularly preferably 0 mol%. By making the content of the structural unit represented by formula (A2) 99.0 mol% or less, the release properties of the release layer can be improved.

[0106] In the (meth)acrylic resin, the content of the structural unit represented by formula (A2) is preferably 99.0% by mass or less, more preferably 93.0% by mass or less, more preferably 70.0% by mass or less, more preferably 55.0% by mass or less, more preferably 40.0% by mass or less, more preferably 35.0% by mass or less, more preferably 25.0% by mass or less, more preferably 15.0% by mass or less, more preferably 10.0% by mass or less, more preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and particularly preferably 0% by mass, relative to the total amount (100% by mass) of the structural units represented by formula (A). By making the content of the structural unit represented by formula (A2) 99.0% by mass or less, the releasability of the release layer can be improved.

[0107] (Structural Unit Represented by Formula (A3)) It is preferable that the (meth)acrylic resin further contains a structural unit represented by the following formula (A3) as the structural unit represented by formula (A). That is, in the (meth)acrylic resin, it is preferable that the structural unit represented by the above formula (A) contains a structural unit represented by the above formula (A1) and a structural unit represented by the following formula (A3). The structural unit represented by the following formula (A3) can improve the releasability of the release layer.

[0108] (In the above formula (A3), R 1 represents a hydrogen atom or a methyl group, R 7 represents a monovalent organic group containing a siloxane bond.

[0109] In the above formula (A3), R 7 means a monovalent group containing at least one carbon atom and at least one siloxane bond (≡Si—O—). In the present invention, the “≡” in “≡Si” means three single bonds.

[0110] The structural unit represented by the above formula (A3) is preferably a structural unit represented by the following formula (A3-a): The structural unit represented by the following formula (A3-a) contains repeating siloxane bonds, and can improve the releasability of the release layer.

[0111] (In formula (A3-a), R 1 represents a hydrogen atom or a methyl group, R 8 represents an alkylene group having 1 to 10 carbon atoms, and R 9 represents an alkyl group having 1 to 12 carbon atoms, and p represents an integer of 2 or more.

[0112] In formula (A3-a), R 8 The number of carbon atoms in the alkylene group represented by the formula is preferably 1 to 10, and more preferably 1 to 5. 8 Examples of the alkylene group represented by the formula include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, etc. Among these, an n-propylene group (-CH-CH-CH-) is preferred.

[0113] In formula (A3-a), R 9 The number of carbon atoms in the alkyl group represented by R is preferably 1 to 12, and more preferably 1 to 5. 9 Examples of the alkyl group represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, etc. Among these, a methyl group, an ethyl group, and an n-butyl group are preferred, and an n-butyl group is more preferred.

[0114] In formula (A3-a), p is preferably 2 or greater, more preferably 5 or greater, and more preferably 10 or greater. In formula (A3-a), p is preferably 300 or less, more preferably 200 or less, and more preferably 150 or less.

[0115] The structural unit represented by formula (A3) is preferably a structural unit derived from a siloxane bond-containing (meth)acrylate represented by the following formula (A3-1).

[0116] (In formula (A3-1), R 1 represents a hydrogen atom or a methyl group, R 8 represents an alkylene group having 1 to 10 carbon atoms, and R 9 represents an alkyl group having 1 to 12 carbon atoms, and p represents an integer of 2 or more.

[0117] In addition, R in the above formula (A3-1) 8 , R 9 , and p are R in the above formula (A3-a), respectively. 8 , R 9 , and p are the same as those for p, and therefore, description thereof will be omitted. Note that, hereinafter, the siloxane bond-containing (meth)acrylate represented by the above formula (A3-1) will also be simply referred to as "siloxane bond-containing (meth)acrylate (A3-1)."

[0118] Examples of the siloxane bond-containing (meth)acrylate (A3-1) include α-butyl-ω-(3-methacryloxypropyl)polydimethylsiloxane and α-mono(methacryloxymethyl)polydimethylsiloxane.

[0119] The number average molecular weight (Mn) of the siloxane bond-containing (meth)acrylate (A3-1) is preferably 500 or more, more preferably 1000 or more, and even more preferably 3000 or more. The number average molecular weight (Mn) of the siloxane bond-containing (meth)acrylate (A3-1) is preferably 25000 or less, more preferably 15000 or less, and even more preferably 10000 or less. When the number average molecular weight (Mn) of the siloxane bond-containing (meth)acrylate (A3-1) is 500 or more, the release properties of the release layer can be improved. When the number average molecular weight (Mn) of the siloxane bond-containing (meth)acrylate (A3-1) is 25000 or less, a release layer with improved release properties can be formed while maintaining wettability with respect to the coating liquid.

[0120] The number average molecular weight (Mn) of the siloxane bond-containing (meth)acrylate (A3-1) refers to the value obtained by converting the molecular weight measured by gel permeation chromatography (GPC) into polystyrene equivalent. For example, it can be measured under the following measurement conditions. The siloxane bond-containing (meth)acrylate (A3-1) is dissolved in tetrahydrofuran to obtain a measurement sample with a siloxane bond-containing (meth)acrylate (A3-1) concentration of 2.0 g / L. Using this measurement sample, the number average molecular weight of the siloxane bond-containing (meth)acrylate (A3-1) can be measured using a gel permeation chromatograph (GPC) equipped with a refractive index detector (RID) under the following measurement apparatus and measurement conditions. Measurement equipment: Tosoh Corporation, product name "HLC-8320GPC" Differential refractive index detector: RI detector built into the above measurement equipment Column: Tosoh Corporation, product name "TSKgel Super HZM-H", two columns Mobile phase: tetrahydrofuran Column flow rate: 0.35 mL / min Sample concentration: 2.0 g / L Injection volume: 10 μL Measurement temperature: 40°C Molecular weight marker: standard polystyrene (standard material manufactured by POLYMER LABORATORIES LTD.) (POLYSTYRENE-MEDIUM MOLECULAR WEIGHT CALIBRATION KIT)

[0121] In the (meth)acrylic resin, the content of the structural unit represented by formula (A3) is preferably 0.1 mol% or more, more preferably 0.3 mol% or more, more preferably 0.6 mol% or more, and more preferably 0.8 mol% or more, relative to 100 mol% of the total amount of the structural units represented by formula (A). In the (meth)acrylic resin, the content of the structural unit represented by formula (A3) is preferably 6.0 mol% or less, more preferably 4.0 mol% or less, more preferably 2.3 mol% or less, more preferably 1.8 mol% or less, more preferably 1.5 mol% or less, and more preferably 1.2 mol% or less, relative to 100 mol% of the total amount of the structural units represented by formula (A). By setting the content of the structural unit represented by formula (A3) to 0.1 mol% or more, it is possible to impart excellent releasability to the release layer. By setting the content of the structural unit represented by formula (A3) to 6.0 mol% or less, it is possible to reduce the decrease in wettability with respect to the coating liquid.

[0122] In the (meth)acrylic resin, the content of the structural unit represented by formula (A3) is preferably 1.0% by mass or more, more preferably 2.5% by mass or more, more preferably 5.0% by mass or more, more preferably 7.5% by mass or more, and more preferably 9.0% by mass or more, relative to 100% by mass of the total amount of the structural units represented by formula (A). In the (meth)acrylic resin, the content of the structural unit represented by formula (A3) is preferably 50.0% by mass or less, more preferably 40.0% by mass or less, more preferably 30.0% by mass or less, more preferably 22.0% by mass or less, more preferably 18.0% by mass or less, and more preferably 12.0% by mass or less, relative to 100% by mass of the total amount of the structural units represented by formula (A). By making the content of the structural unit represented by formula (A3) 1.0% by mass or more, it is possible to impart excellent releasability to the release layer. By setting the content of the structural unit represented by formula (A3) to 50.0% by mass or less, it is possible to reduce the decrease in wettability with respect to the coating liquid.

[0123] The content of each structural unit represented by formula (A) in the (meth)acrylic resin can be calculated, for example, from the amount of monomer charged during synthesis of the (meth)acrylic resin. It should be noted that a structural unit derived from the siloxane bond-containing (meth)acrylate represented by formula (A3-1) above can be used as the structural unit represented by formula (A3). In such a case, when calculating the content (mol %) of the structural unit derived from the siloxane bond-containing (meth)acrylate represented by formula (A3-1) in the (meth)acrylic resin, the number average molecular weight (Mn) of the siloxane bond-containing (meth)acrylate represented by formula (A3-1) above is used as the molecular weight of the structural unit derived from the siloxane bond-containing (meth)acrylate represented by formula (A3-1).

[0124] (Structural Unit Represented by Formula (A4)) The (meth)acrylic resin may further contain a structural unit represented by the following formula (A4) as the structural unit represented by formula (A). The structural unit represented by formula (A4) can be used in the (meth)acrylic resin without impairing the effects obtained by the structural unit represented by formula (A1).

[0125] (In the above formula (A4), R 1 represents a hydrogen atom or a methyl group, R 10 represents an alkylene group.

[0126] In the above formula (A4), R 10 The number of carbon atoms in the alkylene group represented by the formula (A4) is preferably 4 or less. 10 The alkylene group represented by the formula (I) preferably has 1 or more carbon atoms.

[0127] In the above formula (A4), R 10Examples of the alkylene group represented by the formula (I) include linear alkylene groups such as methylene, ethylene, n-propylene, n-butylene, n-pentylene, and n-hexylene; and branched alkylene groups such as isopropylene [—CH(CH)—CH—], ​​isobutylene, sec-butylene, t-butylene, isopentylene, and neopentylene. Of these, linear alkylene groups are preferred, with ethylene, n-propylene, and n-butylene being more preferred.

[0128] The structural unit represented by the above formula (A4) is preferably a structural unit derived from a hydroxyalkyl (meth)acrylate (A4).

[0129] Examples of the hydroxyalkyl (meth)acrylate (A4) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Preferred examples of the hydroxyalkyl (meth)acrylate (A4) include 2-hydroxypropyl (meth)acrylate and 3-hydroxypropyl (meth)acrylate, and more preferred is 3-hydroxypropyl (meth)acrylate.

[0130] In the (meth)acrylic resin, the content of the structural unit represented by formula (A4) is preferably 40.0 mol% or less, more preferably 30.0 mol% or less, more preferably 20.0 mol% or less, more preferably 10.0 mol% or less, and more preferably 5.0 mol% or less, relative to 100 mol% of the total amount of the structural units represented by formula (A).

[0131] In the (meth)acrylic resin, the content of the structural unit represented by formula (A4) is preferably 40.0% by mass or less, more preferably 30.0% by mass or less, more preferably 20.0% by mass or less, more preferably 10.0% by mass or less, and more preferably 5.0% by mass or less, relative to 100% by mass of the total amount of the structural units represented by formula (A).

[0132] The (meth)acrylic resin may further contain, as the structural unit represented by the formula (A), structural units other than the structural units represented by the formulas (A1) to (A4) described above. Examples of the structural units include structural units derived from (meth)acrylic monomers such as the above-mentioned epoxy group-containing (meth)acrylates and (meth)acrylic acid.

[0133] As described above, the (meth)acrylic resin contains a structural unit represented by the formula (A). In the (meth)acrylic resin, the number of carbon atoms adjacent to the monovalent organic group represented by X in the formula (A) is preferably 13.0 or more on a molar average basis. This allows the monovalent organic group represented by X in the formula (A) to function as an excellent hydrophobic moiety, thereby further improving the releasability of the release layer.

[0134] In the monovalent organic group represented by X in the above formula (A), the carbon atom adjacent to which is a carbon atom or a hydrogen atom (also simply referred to as a "non-heterobonded carbon atom") means a carbon atom contained in the monovalent organic group (X) to which the atom directly bonded is a carbon atom or a hydrogen atom. A non-heterobonded carbon atom is a carbon atom to which only a carbon atom or a hydrogen atom is directly bonded, and no heteroatom is directly bonded, among the carbon atoms constituting the monovalent organic group (X). Note that "heteroatom" means all atoms other than carbon atoms and hydrogen atoms.

[0135] For example, when a structural unit represented by formula (A1-a1) is used as a structural unit derived from the addition reaction product (A1-1) of glycidyl methacrylate and stearic acid, the "non-hetero bonded carbon atom" in this structural unit is the carbon atom indicated by the black circle in the formula on the left below. Therefore, the number of non-hetero bonded carbon atoms (N i ) is "17". Furthermore, when a structural unit derived from 3-hydroxypropyl methacrylate is used as the structural unit represented by formula (A4), the "non-hetero bonded carbon atom" in this structural unit is the carbon atom indicated by the black circle in the formula on the right below. Therefore, the number of non-hetero bonded carbon atoms (N i ) becomes "1".

[0136]

[0137] For each structural unit represented by formula (A), the number of non-hetero bonded carbon atoms (N i Next, the number N of non-hetero bonded carbon atoms in the structural unit is counted. i and the content m of this structural unit i Using this (mol %), the number (molar average) of non-heterobonded carbon atoms in the monovalent organic group represented by X in the above formula (A) in the (meth)acrylic resin can be calculated based on the following formula:

[0138] In the (meth)acrylic resin, the number (molar average) of carbon atoms (non-heterobonded carbon atoms) adjacent to which are carbon atoms or hydrogen atoms in the monovalent organic group represented by X in formula (A) = [(N1 × m1) + (N2 × m2) + ... + (N i ×m i )] / 100 (in the formula, N i is the number of non-hetero bonded carbon atoms in the monovalent organic group represented by X in the i-th structural unit of the structural units represented by formula (A), and m i is the content (mol %) of the i-th type of structural unit relative to 100 mol % of the total amount of structural units represented by formula (A) in the (meth)acrylic resin, and i is an integer representing the number of types of structural units represented by formula (A).

[0139] In the (meth)acrylic resin, in the monovalent organic group represented by X in the above formula (A), the molar average number of carbon atoms (non-heterobonded carbon atoms) adjacent to a carbon atom or a hydrogen atom is preferably 13.0 or more, more preferably 15.0 or more, more preferably 17.0 or more, more preferably 19.0 or more, more preferably 20.0 or more. In the (meth)acrylic resin, in the monovalent organic group represented by X in the above formula (A), the molar average number of carbon atoms (non-heterobonded carbon atoms) adjacent to a carbon atom or a hydrogen atom is preferably 30.0 or less, more preferably 25.0 or less, more preferably 23.0 or less, more preferably 22.0 or less. By setting the molar average number of non-heterobonded carbon atoms to 6.0 or more, the releasability of the release layer can be improved. By setting the molar average number of non-heterobonded carbon atoms to 30.0 or less, a release layer with improved releasability can be formed while maintaining wettability to the coating liquid.

[0140] The iodine value of the (meth)acrylic resin is 50 gI / 100 g or less, preferably 40 gI / 100 g or less, more preferably 37 gI / 100 g or less, more preferably 30 gI / 100 g or less, more preferably 25 gI / 100 g or less, more preferably 20 gI / 100 g or less, and more preferably 10 gI / 100 g or less. By making the iodine value of the (meth)acrylic resin 50 gI / 100 g or less, the releasability of the release layer formed by the (meth)acrylic resin can be improved.

[0141] The iodine value of the (meth)acrylic resin can be measured in accordance with JIS K 0070:1992.

[0142] The hydroxyl value of the (meth)acrylic resin is preferably 5.0 mgKOH / g or more, more preferably 30.0 mgKOH / g or more, more preferably 50.0 mgKOH / g or more, more preferably 70.0 mgKOH / g or more, more preferably 90.0 mgKOH / g or more, more preferably 95.0 mgKOH / g or more, and more preferably 100.0 mgKOH / g or more. The hydroxyl value of the (meth)acrylic resin is preferably 200.0 mgKOH / g or less, more preferably 180.0 mgKOH / g or less, more preferably 150.0 mgKOH / g or less, and more preferably 120.0 mgKOH / g or less. When the hydroxyl value of the (meth)acrylic resin is 5.0 mgKOH / g or more, the releasability of the release layer can be improved. When the hydroxyl value of the (meth)acrylic resin is 200.0 mgKOH / g or less, a release layer having improved releasability can be formed while maintaining wettability with respect to the coating liquid.

[0143] The hydroxyl value of the (meth)acrylic resin can be measured in accordance with JIS K 0070:1992.

[0144] (Method for Producing (Meth)acrylic Resin) The method for producing the (meth)acrylic resin is not particularly limited. For example, the (meth)acrylic resin can be produced by polymerizing a monomer, such as a (meth)acrylic monomer, from which each structural unit is derived, preferably in the presence of a polymerization initiator.

[0145] In producing the (meth)acrylic resin, the order in which the monomers are polymerized is not particularly limited. All of the monomers, such as the (meth)acrylic monomer, which derive the respective structural units may be polymerized simultaneously.

[0146] When a structural unit derived from a (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto is used as the structural unit represented by formula (A1), the (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto may be synthesized in advance, and then the (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto and, if necessary, other (meth)acrylic monomers may be polymerized. Alternatively, the (meth)acrylic monomer (A1) before the aliphatic hydrocarbon group is added may be polymerized with other (meth)acrylic monomers if necessary, and then the aliphatic hydrocarbon group may be added to the (meth)acrylic monomer (A1). Examples of other (meth)acrylic monomers include alkyl (meth)acrylates (A2), siloxane bond-containing (meth)acrylates (A3-1), and hydroxyalkyl (meth)acrylates (A4). One or more of these other (meth)acrylic monomers may be used as necessary.

[0147] For example, when an addition reaction product (A1-1) of an epoxy group-containing (meth)acrylate and an aliphatic hydrocarbon compound (E1) having an epoxy-reactive group is used as the (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto, the (meth)acrylic resin can be produced, for example, by the following method (A1-1).

[0148] The method (A1-1) for producing a (meth)acrylic resin comprises: first, a polymerization step of polymerizing an epoxy group-containing (meth)acrylate and, if necessary, monomers containing other (meth)acrylic monomers, preferably in the presence of a polymerization initiator, to obtain a polymer; and a ring-opening addition step of subjecting an aliphatic hydrocarbon compound (E1) having an epoxy-reactive group to a ring-opening addition reaction, in the presence of a ring-opening addition catalyst, with an epoxy group contained in a structural unit derived from the epoxy group-containing (meth)acrylate contained in the polymer, to obtain a (meth)acrylic resin having structural units derived from the addition reaction product (A1-1).

[0149] Furthermore, for example, when an addition reaction product (A1-2) of (meth)acrylic acid and an aliphatic hydrocarbon compound (E2) having an epoxy group or a glycidyloxy group is used as the (meth)acrylic monomer (A1) having an aliphatic hydrocarbon group added thereto, the (meth)acrylic resin can be produced, for example, by the following method (A1-2).

[0150] The method (A1-2) for producing a (meth)acrylic resin comprises: an initial polymerization step of polymerizing monomers containing (meth)acrylic acid and, as necessary, other (meth)acrylic monomers, preferably in the presence of a polymerization initiator, to obtain a polymer; and a ring-opening addition step of subjecting aliphatic hydrocarbon compound (E2) having an epoxy group or a glycidyloxy group to a carboxy group contained in a structural unit derived from (meth)acrylic acid, contained in the polymer, in the presence of a ring-opening addition catalyst, to obtain a (meth)acrylic resin having structural units derived from the addition reaction product (A1-2).

[0151] In the above methods (A1-1) and (A1-2), a thermal polymerization initiator is preferably used as the polymerization initiator. Examples of the thermal polymerization initiator include organic peroxides such as methyl ethyl ketone peroxide, acetylacetone peroxide, t-butyl peroxybenzoate, benzoyl peroxide, dicumyl peroxide, cumene hydroperoxide, and tert-butylperoxy-2-ethylhexanoate. The polymerization of the monomers is preferably carried out under heating. The polymerization temperature is preferably 80 to 140°C. The polymerization step may be carried out in the presence of an aliphatic hydrocarbon compound (E1) or an aliphatic hydrocarbon compound (E2).

[0152] In the above methods (A1-1) and (A1-2), known catalysts capable of promoting the ring-opening addition reaction of epoxy groups can be used as the ring-opening addition catalyst. Examples of the catalyst include tertiary amines such as dimethylbenzylamine, triethylamine, tetramethylethylenediamine, and tri-n-octylamine; quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, and tetrabutylammonium bromide; alkyl ureas such as tetramethylurea; alkyl guanidines such as tetramethylguanidine; and tertiary phosphines such as triphenylphosphine. The ring-opening addition reaction is preferably carried out while heating. The ring-opening addition reaction temperature is preferably 90 to 150°C.

[0153] As described above, the (meth)acrylic resin of the present invention can form a release layer having improved releasability after curing while maintaining wettability with respect to a coating liquid. Therefore, the (meth)acrylic resin is preferably a resin for forming a release layer.

[0154]

[0023] The present invention further provides a curable composition comprising the (meth)acrylic resin and a curing agent, which, after curing, can form a cured product that maintains wettability with respect to a coating liquid and has improved releasability.

[0155] The curing agent may be any agent capable of reacting with the hydroxyl groups of the (meth)acrylic resin to form crosslinks. Examples of the curing agent include melamine compounds, polyisocyanate compounds, and epoxy compounds. Among these, melamine compounds are preferred. Melamine compounds can improve releasability. The curing agent may be used alone or in combination of two or more.

[0156] organic group R 2 It is presumed that a crosslinking reaction occurs between the hydroxyl groups of the curing agent and the resin, thereby forming a release layer that maintains wettability with respect to the coating liquid while improving releasability.

[0157] As the melamine compound, known compounds such as melamine and its derivatives can be used. A melamine compound obtained by condensing melamine with formaldehyde and having one or more triazine rings, one or more methylol groups and / or one or more alkoxymethyl groups in one molecule is preferred.

[0158] The melamine compound is preferably a compound represented by the following formula (M1).

[0159]

[0160] In the above formula (M1), R 11 ~R 16 R each independently represents a hydrogen atom, a methylol group (-CHOH), a methoxymethyl group (-CHOCH), an ethoxymethyl group (-CHOCHCH), an n-butoxymethyl group (-CHOCHCHCHCHCH), or an isobutoxymethyl group (-CHOCHCH(CH)). 11 ~R 16 At least one of these is preferably a methoxymethyl group.

[0161] Specific examples of the melamine compound include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, hexamethylol melamine, and hexamethylol melamine compounds in which 1 to 6 methylol groups are methoxymethylated, or mixtures thereof. One type of melamine compound may be used alone, or two or more types may be used in combination.

[0162] The content of the melamine compound in the curable composition is preferably 1 part by mass or more, more preferably 5 parts by mass or more, per 100 parts by mass of the (meth)acrylic resin. The content of the melamine compound in the curable composition is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, per 100 parts by mass of the (meth)acrylic resin.

[0163] The curable composition may contain a solvent. At least one of the base agent and the curing agent contained in the curable composition may contain a solvent. When the base agent contains a solvent, the solids concentration of the base agent is preferably 10 to 90 mass%, more preferably 20 to 80 mass%. When the curing agent contains a solvent, the solids concentration of the curing agent is preferably 90 to 99.9 mass%, more preferably 95 to 99.7 mass%.

[0164] Examples of the solvent include hydrocarbon organic solvents such as heptane, toluene, xylene, octane, and mineral spirits; ester organic solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, and diethylene glycol monobutyl ether acetate; ketone organic solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; alcohol organic solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol, and isobutanol; ether organic solvents such as n-butyl ether and dioxane; glycol ether organic solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; and aromatic petroleum organic solvents. The solvents may be used alone or in combination of two or more.

[0165] The curable composition may contain additives. Examples of additives include defoamers, antistatic agents, antifogging agents, colorants, ultraviolet absorbers, light stabilizers, antioxidants, surface conditioners, and surfactants. The additives may be contained in either the base agent or the curing agent.

[0166] As described above, the curable composition can form a cured product having improved releasability while maintaining wettability with a coating liquid after curing. Therefore, such a curable composition can be suitably used as a release agent.

[0167] The use of the curable composition is not limited to a release agent, and examples of uses of the curable composition include a water-repellent coating agent and an antifouling coating agent in addition to a release agent.

[0168] <Multilayer Sheet> The present invention further provides a multilayer sheet formed using the curable composition described above. The multilayer sheet includes a substrate and a layer that is a cured product of the curable composition. The curable composition can form a layer that, after curing, maintains wettability with respect to a coating liquid while improving releasability.

[0169] Examples of the substrate include synthetic resin films. Examples of synthetic resins contained in the synthetic resin film include polyethylene, polypropylene, cycloolefin polymer (COP), polyisobutylene, polybutadiene, polyvinyl acetate, polyvinyl chloride, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), nylon, polystyrene, polyurethane, triacetyl cellulose (TAC), polycarbonate (PC), polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyethersulfone, polycarbonate, polyacetal, polyimide resin, AS resin, ABS resin, melamine resin, (meth)acrylic resin (excluding the (meth)acrylic resin of the present application), epoxy resin, and polyester resin. Among these, polyethylene, polypropylene, and polyethylene terephthalate are preferred, and polyethylene terephthalate is more preferred.

[0170] The surface of the synthetic resin film may be subjected to a surface treatment such as a corona treatment, etc. The thickness of the synthetic resin film is not particularly limited, but is preferably 1 to 300 μm.

[0171] The thickness of the layer that is the cured product of the curable composition is not particularly limited, but is preferably 10 nm to 5 μm, more preferably 20 nm to 1 μm, and even more preferably 50 nm to 500 nm.

[0172] The method for producing the multilayer sheet is not particularly limited. For example, a layer made of a cured product of the curable composition can be formed by applying a curable composition to at least one surface of a substrate and then heating and curing the applied composition. The heating of the curable composition is not particularly limited, and may be performed at 100 to 160°C for 5 to 150 seconds.

[0173] The multilayer sheet includes a layer that is a cured product of a curable composition. This layer has both releasability and wettability to a coating liquid, and therefore, the layer is preferably a release layer. Therefore, the multilayer sheet is suitably used as a release sheet.

[0174] When the multilayer sheet is used as a release sheet, by forming a release layer on the substrate using the (meth)acrylic resin of the present application, it is possible to obtain a release sheet with improved releasability while maintaining wettability with respect to the coating liquid.

[0175] The use of the multilayer sheet is not limited to release sheets, and examples of the use of the multilayer sheet include easy-slip sheets, antifouling films, paint protection films (PPF), and the like, in addition to release sheets.

[0176] Multilayer sheets can be used for various purposes. For example, they can be used as protective sheets for protecting the adhesive surface of pressure-sensitive adhesive sheets or patches. In such cases, a pressure-sensitive adhesive layer is formed by coating and drying a pressure-sensitive adhesive solution containing a pressure-sensitive adhesive and a solvent on a layer (release layer) made of a cured product of a curable composition of the multilayer sheet. Furthermore, other layers contained in the pressure-sensitive adhesive sheet or patch are laminated on the pressure-sensitive adhesive layer. This results in a pressure-sensitive adhesive sheet or patch whose adhesive surface is protected by the multilayer sheet. When using the pressure-sensitive adhesive sheet or patch, the multilayer sheet can be peeled off from the pressure-sensitive adhesive sheet or patch to expose the adhesive surface.

[0177] The multilayer sheet is also suitable as a process film for producing a multilayer ceramic electronic component. Specifically, a ceramic slurry is first applied to a layer (release layer) of the multilayer sheet, which is made of a cured product of the curable composition, and then dried to form a ceramic green sheet. Next, electrodes having a desired pattern are printed on the ceramic green sheet, and the multilayer sheet is then peeled off from the ceramic green sheet. The ceramic green sheets are then stacked, pressed, and fired, and external electrodes are provided to produce a multilayer ceramic electronic component.

[0178] The ceramic slurry contains ceramic, a binder resin, a solvent, and the like.

[0179] Examples of ceramics include barium titanate, ferrite, titanium oxide, alumina, zirconia, zinc oxide, sialon, spinemullite, aluminum silicate, aluminum nitride, silicon nitride, magnesia, and silicon carbide. Barium titanate is preferred. One type of ceramic may be used alone, or two or more types may be used in combination. The average particle size of the ceramic is not particularly limited, but is preferably 0.01 to 5.0 μm.

[0180] Examples of binder resins that can be used include aqueous polymers such as polyurethane resins, urea resins, melamine resins, epoxy resins, vinyl acetate resins, (meth)acrylic resins (excluding the (meth)acrylic resins of the present application), polyvinyl alcohol, and polyvinyl butyral. The binder resins may be used alone or in combination of two or more.

[0181] Examples of the solvent include organic solvents. Specific examples include alcohol solvents such as ethanol, n-propanol, isopropanol, and n-butanol; hydrocarbon solvents such as toluene, xylene, methylcyclohexane, and terpineol; ether solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate, and propylene glycol monomethyl ether acetate. These solvents may be used alone or in combination of two or more.

[0182] The ceramic slurry may further contain other additives such as plasticizers, dispersants, antistatic agents, and surfactants. Plasticizers are preferred. Examples of plasticizers include phthalates such as dioctyl phthalate.

[0183] The thickness of the ceramic green sheet is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 0.5 to 50 μm, and even more preferably 0.5 to 10 μm.

[0184] The layer of the cured product of the curable composition in the multilayer sheet has excellent wettability with coating liquids such as adhesive solutions and ceramic slurries. Therefore, when forming a coating layer by applying a coating liquid to the layer of the cured product of the curable composition in the multilayer sheet, the coating liquid can wet and spread on the layer of the cured product of the curable composition without causing repelling. This allows the formation of a coating layer with a uniform thickness without the formation of holes or recesses. Examples of the coating layer include the adhesive layer and ceramic green sheet described above.

[0185] In recent years, the thickness of coating layers such as pressure-sensitive adhesive layers and ceramic green sheets has been reduced. This reduction in thickness has been particularly noticeable in ceramic green sheets. Therefore, the multilayer sheet can be suitably used as a process film for producing multilayer ceramic electronic components, as it can particularly exhibit the effects of the present invention.

[0186] The present invention will be described in more detail below using examples, but the present invention is not limited thereto. Specific numerical values ​​of blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or greater than") of the corresponding blending ratios (content ratios), physical property values, parameters, etc. described in the "Summary of the Invention" and "Description of the Invention."

[0187] The compounds used in the following synthesis examples and comparative synthesis examples are listed below. (Epoxy group-containing (meth)acrylate) GMA: glycidyl methacrylate

[0188] (Aliphatic hydrocarbon compound (E1) having a carboxy group) Stearic acid Behenic acid Tall oil fatty acid (composition: saturated fatty acids: palmitic acid 2.0% by mass, stearic acid 2.0% by mass, and unsaturated fatty acids: oleic acid 46.0% by mass, linoleic acid 50.0% by mass)

[0189] (Alkyl (meth)acrylate (A2)) SMA: stearyl methacrylate VA: behenyl acrylate 2EHA: 2-ethylhexyl acrylate (2-ethylhexyl acrylate)

[0190] (Siloxane bond-containing (meth)acrylate (A3-1)) FM-0721: (Meth)acrylate represented by the above formula (A3-1) (wherein R 1 represents a methyl group, and R 8 represents an n-propylene group, and R 9 represents an n-butyl group, and p represents an integer of 2 or greater) (α-butyl-ω-(3-methacryloxypropyl)polydimethylsiloxane, number average molecular weight (Mn) 5000, manufactured by JNC Corporation, trade name "Silaplane FM-0721")

[0191] (Hydroxyalkyl (meth)acrylate (A4)) HPMA: 3-hydroxypropyl methacrylate

[0192] (Examples 1A to 9A and Comparative Example 2A) A separable flask was charged with 100 parts by mass of stearic acid, behenic acid, tall oil fatty acid, and toluene, each in the amounts shown in Table 1, and the mixture was heated to 100° C. with stirring. Next, (meth)acrylic monomers including glycidyl methacrylate (GMA), siloxane bond-containing (meth)acrylate (FM-0721), 3-hydroxypropyl methacrylate (HPMA), stearyl methacrylate (SMA), behenyl acrylate (VA), and 2-ethylhexyl acrylate (2EHA), each in the amounts shown in Table 1, and 3 parts by mass of a thermal polymerization initiator (manufactured by NOF Corporation, product name "Perbutyl O," tert-butylperoxy-2-ethylhexanoate) were added dropwise to the separable flask over 90 minutes. After the completion of the dropwise addition, the temperature was maintained at 100° C. for 2 hours to obtain a polymer of (meth)acrylic monomers with a solid content of 50% by mass (polymerization step).

[0193] Next, 1 part by mass of triphenylphosphine was added to the separable flask as a ring-opening addition catalyst, and the mixture was stirred at 110°C for 5 hours to carry out a ring-opening addition reaction between the epoxy groups contained in the structural units derived from glycidyl methacrylate in the polymer and stearic acid, behenic acid, or tall oil fatty acid (ring-opening addition step). Thereafter, the contents of the separable flask were cooled to 25°C to obtain a (meth)acrylic resin.

[0194] Comparative Example 1A: 100 parts by mass of toluene was placed in a separable flask and heated to 100°C while stirring. Next, (meth)acrylic monomers containing 3-hydroxypropyl methacrylate (HPMA) and stearyl methacrylate (SMA), and 3 parts by mass of a thermal polymerization initiator (manufactured by NOF Corporation, product name "Perbutyl O," tert-butylperoxy-2-ethylhexanoate) in the amounts shown in Table 1 were added dropwise to the separable flask over 90 minutes. After the completion of the addition, the temperature was maintained at 100°C for 2 hours to obtain a polymer of the (meth)acrylic monomer (polymerization step). The contents of the separable flask were then cooled to 25°C to obtain a (meth)acrylic resin with a solids content of 50% by mass.

[0195] The iodine value and hydroxyl value of the (meth)acrylic resin are shown in Table 1. Furthermore, in the (meth)acrylic resin, the molar average number of non-hetero-bonded carbon atoms in the monovalent organic group represented by X in the above formula (A) is shown in the column of "Molar average number of non-hetero-bonded carbon atoms" in Table 1.

[0196] The (meth)acrylic resins obtained in the above-mentioned Examples and Comparative Examples contained the following structural unit as the structural unit represented by the above formula (A1).

[0197] [Structural Unit Derived from the Addition Reaction Product (A1-1) of Glycidyl Methacrylate and Stearic Acid] Structural unit (A1-a1-1s) [the above formula (A1-a1) (R 1 is a methyl group, and R 3 is a heptadecyl group (-C 17 H 35 ))] structural unit (A1-b1-1s) [represented by the above formula (A1-b1)(R 1is a methyl group, and R 3 is a heptadecyl group (-C 17 H 35 ) is a structural unit represented by

[0198] [Structural unit derived from the addition reaction product (A1-1) of glycidyl methacrylate and behenic acid] Structural unit (A1-a1-2) [the above formula (A1-a1) (R 1 is a methyl group, and R 3 is a henicosyl group (-C 21 H 43 ))] structural unit (A1-b1-2) [represented by the above formula (A1-b1) (R 1 is a methyl group, and R 3 is a henicosyl group (-C 21 H 43 ) is a structural unit represented by

[0199] [Structural unit derived from the addition reaction product (A1-1) of glycidyl methacrylate and palmitic acid of tall oil fatty acid] Structural unit (A1-a1-3) [the above formula (A1-a1) (R 1 is a methyl group, and R 3 is a pentadecyl group (-C 15 H 31 ))] structural unit (A1-b1-3) [represented by the above formula (A1-b1) (R 1 is a methyl group, and R 3 is a pentadecyl group (-C 15 H 31 ) is a structural unit represented by

[0200] [Structural Units Derived from the Addition Reaction Product (A1-1) of Glycidyl Methacrylate and Stearic Acid of Tall Oil Fatty Acid] Structural unit (A1-a1-1t) [the above formula (A1-a1) (R 1 is a methyl group, and R 3 is a heptadecyl group (-C 17 H 35 ))] structural unit (A1-b1-1t) [represented by the above formula (A1-b1) (R 1 is a methyl group, and R 3 is a heptadecyl group (-C 17 H 35) is a structural unit represented by

[0201] [Structural unit derived from the addition reaction product (A1-1) of glycidyl methacrylate and oleic acid of tall oil fatty acid] Structural unit (A1-a1-4) [the above formula (A1-a1) (R 1 is a methyl group, and R 3 is a heptadecenyl group (-C 17 H 33 ))] structural unit (A1-b1-4) [represented by the above formula (A1-b1) (R 1 is a methyl group, and R 3 is a heptadecenyl group (-C 17 H 33 ) is a structural unit represented by

[0202] [Structural unit derived from the addition reaction product (A1-1) of glycidyl methacrylate and linoleic acid of tall oil fatty acid] Structural unit (A1-a1-5) [the above formula (A1-a1) (R 1 is a methyl group, and R 3 is a heptadecadienyl group (-C 17 H 31 ))] structural unit (A1-b1-5) [represented by the above formula (A1-b1) (R 1 is a methyl group, and R 3 is a heptadecadienyl group (-C 17 H 31 ) is a structural unit represented by

[0203] Furthermore, the (meth)acrylic resins obtained in the above-mentioned Examples and Comparative Examples contained, as the structural unit represented by the above formula (A2), a structural unit derived from stearyl methacrylate (SMA), a structural unit derived from behenyl acrylate (VA), and a structural unit derived from 2-ethylhexyl acrylate (2EHA).

[0204] Furthermore, the (meth)acrylic resins obtained in the above-mentioned Examples and Comparative Examples contained a structural unit derived from a siloxane bond-containing (meth)acrylate (FM-0721) as the structural unit represented by the above formula (A3).

[0205] The (meth)acrylic resins obtained in the above-mentioned Examples and Comparative Examples contained a structural unit derived from 3-hydroxypropyl methacrylate (HPMA) as the structural unit represented by the above formula (A4).

[0206] The content (mol %) of each of the structural units represented by the formulas (A1) to (A4) in the (meth)acrylic resin relative to 100 mol % of the total amount of structural units represented by the formula (A) is shown in Table 2. Furthermore, the content (mass %) of each of the structural units represented by the formulas (A1) to (A4) in the (meth)acrylic resin relative to 100 mass % of the total amount of structural units represented by the formula (A) is shown in Table 3.

[0207] (Examples 1B to 9B and Comparative Examples 1B to 2B) Curable compositions were obtained by mixing the (meth)acrylic resins obtained in Examples 1A to 9A and Comparative Examples 1A to 2A, a melamine compound (manufactured by Allnex under the trade name "Cymel 303LF"), and 81 parts by mass of toluene in the amounts shown in Table 4. In Table 4, the amount of (meth)acrylic resin including toluene (parts by mass, solids content: 50% by mass) is shown.

[0208] The curable composition was applied to a PET (polyethylene terephthalate) film (thickness: 50 μm) using a bar coater, and then cured by heating in an oven at 120° C. for 30 seconds, thereby obtaining a multilayer sheet having a release layer (dry film thickness: 150 nm) made of a cured product of the curable composition on one side of the PET film.

[0209] [Evaluation] The release properties and wettability to the coating liquid of the release layer of the multilayer sheet were evaluated according to the following procedures. The results are shown in Table 4.

[0210] (Release Property) An adhesive tape (manufactured by Nitto Denko, product name "31B tape", length 130 mm, width 19 mm) was applied to the release layer of the multilayer sheet, and then cured at room temperature (25°C) for 24 hours. The adhesive tape was then peeled off at a peel angle of 180° and a peel speed of 100 mm / sec. At this time, the stress generated during peeling (peel stress) was measured using a load measuring device (manufactured by Imada Seisakusho, product name "Digital Force Gauge DST-50N"). The peel stress was measured for 0.2 to 1.2 seconds after the start of measurement. The peel stress was measured at 0.1 second intervals. The arithmetic mean value of the measured peel stresses was taken as the peel strength (N / 19 mm).

[0211] (Wettability) A mixed solution was obtained by stirring and mixing 42% by mass of toluene, 42% by mass of ethanol, 13% by mass of barium titanate (manufactured by Sakai Chemical Industry Co., Ltd., product name "BT-02"), 2% by mass of polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., product name "S-LEC BM-2"), and 1% by mass of dioctyl phthalate. The mixed solution was dispersed together with 0.05 mm zirconia beads using a rocking shaker for 8 hours, and then the zirconia beads were filtered using a wire mesh (#400 mesh) to obtain a ceramic slurry.

[0212] Next, the ceramic slurry was applied onto the release layer of the multilayer sheet using a bar coater (No. 36) and dried for 2 minutes at 90° C. In this way, a ceramic green sheet was produced on the release layer.

[0213] The appearance of the ceramic green sheet was visually observed and evaluated according to the following evaluation criteria. Evaluation criteria: A: No cissing occurred on the entire ceramic green sheet. B: One to less than five cissing occurred on the entire ceramic green sheet, but this did not cause any problems in practical use. C: Five to less than 20 cissing occurred on the entire ceramic green sheet, but this did not cause any problems in practical use. D: 20 or more cissing occurred on the entire ceramic green sheet.

[0214] The term "cissing" refers to a phenomenon in which holes or crater-like recesses are formed in the ceramic green sheets.

[0215]

[0216]

[0217]

[0218]

[0219] (Cross-reference to related applications) This application claims priority to Japanese Patent Application No. 2024-93351, filed on June 7, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0220] According to the present invention, it is possible to provide a (meth)acrylic resin that can form a release layer having improved releasability while maintaining wettability with a coating liquid.

Claims

1. A (meth)acrylic resin comprising a structural unit represented by the following formula (A), wherein the structural unit represented by formula (A) comprises a structural unit represented by the following formula (A1), and the (meth)acrylic resin has an iodine value of 50 gI / 100 g or less. (In the above formula (A), R 1 represents a hydrogen atom or a methyl group, and X represents a monovalent organic group containing two or more carbon atoms. (In the above formula (A1), R 1 represents a hydrogen atom or a methyl group, R 2 represents a divalent organic group having a hydroxyl group, R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

2. The (meth)acrylic resin according to claim 1, wherein the structural unit represented by formula (A1) is at least one of a structural unit represented by the following formula (A1-a) and a structural unit represented by the following formula (A1-b): (In each of the above formula (A1-a) and the above formula (A1-b), R 1 represents a hydrogen atom or a methyl group, R 4 represents a single bond or an alkylene group having 1 to 3 carbon atoms, R 5 represents a hydrogen atom or a methyl group, L represents a single bond or a divalent linking group, R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

3. The (meth)acrylic resin according to claim 1, wherein the structural unit represented by formula (A1) is at least one of structural units represented by the following formulae (A1-a1) to (A1-a4) and the following formulae (A1-b1) to (A1-b5): (In each of the above formulae (A1-a1) to (A1-a4) and (A1-b1) to (A1-b5), R 1 represents a hydrogen atom or a methyl group, R 3 represents a linear or branched, saturated or unsaturated monovalent aliphatic hydrocarbon group.

4. The (meth)acrylic resin according to claim 1, characterized in that the content of the structural unit represented by formula (A1) is 1.0 mol % or more relative to 100 mol % of the total amount of the structural unit represented by formula (A).

5. The (meth)acrylic resin according to claim 1, characterized in that, as the structural unit represented by formula (A), it further contains a structural unit represented by the following formula (A3) in an amount of 20.0 mass% or less, relative to 100 mass% of the total amount of the structural units represented by formula (A). (In the above formula (A3), R 1 represents a hydrogen atom or a methyl group, R 7 represents a monovalent organic group containing a siloxane bond.

6. The (meth)acrylic resin according to claim 1, characterized in that in the monovalent organic group represented by X in formula (A), the number of carbon atoms adjacent to which is a carbon atom or a hydrogen atom is, on a molar average, 13.0 or more.

7. The (meth)acrylic resin according to claim 1, characterized in that the hydroxyl value is 5.0 mg KOH / g or more.

8. The (meth)acrylic resin according to claim 1, which is a resin for forming a release layer.

9. A curable composition comprising the (meth)acrylic resin according to claim 1 and a curing agent.

10. The curable composition according to claim 9, wherein the curing agent comprises a melamine compound.

11. The curable composition according to claim 9, which is a mold release agent.

12. A multilayer sheet comprising: a substrate; and a layer which is a cured product of the curable composition according to claim 9.

13. The multilayer sheet according to claim 12, which is a release sheet.

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