Curable composition and adhesive

Abstract

To provide a curable composition capable of suppressing white turbidity, and an adhesive.SOLUTION: The curable composition for obtaining the pressure sensitive adhesive contains a (meth) acrylic resin and a compound represented by the following formula (1). The content ratio of the compound represented by the following formula (1) is less than 5.0 parts by mass with respect to 100 parts by mass of the (meth) acrylic resin. (In the formula (1), A represents an n-valent organic group containing a sulfur atom. N represents an integer of 3 or more. R represents a hydrogen atom or a methyl group. Each R may be the same or different from each other. ) SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition and a pressure-sensitive adhesive. [Background technology]

[0002] Conventionally, (meth)acrylic resins have been known in the field of pressure-sensitive adhesives. For example, pressure-sensitive adhesive compositions containing a (meth)acrylic resin and a crosslinking agent are known as raw materials for pressure-sensitive adhesives. Also, pressure-sensitive adhesives obtained by crosslinking the pressure-sensitive adhesive compositions are known.

[0003] More specifically, the following pressure-sensitive adhesive compositions and pressure-sensitive adhesives have been proposed. The pressure-sensitive adhesive composition contains an acrylic resin, a polyfunctional monomer, and a photopolymerization initiator. The polyfunctional monomer contains trimethylolpropane triacrylate (TMPTA). When the pressure-sensitive adhesive composition is irradiated with ultraviolet light, the pressure-sensitive adhesive composition is cured to obtain a pressure-sensitive adhesive (see, for example, Patent Document 1 (Examples 1 and 2)). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-175805 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned pressure-sensitive adhesives may become cloudy, and therefore there is a demand for pressure-sensitive adhesives that are less likely to become cloudy.

[0006] The present invention relates to a curable composition and a pressure-sensitive adhesive that can suppress cloudiness. [Means for solving the problem]

[0007] The present invention [1] is a curable composition for obtaining a pressure-sensitive adhesive, the curable composition containing a (meth)acrylic resin and a compound represented by the following formula (1), wherein the content of the compound represented by the following formula (1) is less than 5.0 parts by mass per 100 parts by mass of the (meth)acrylic resin.

[0008] The curable composition is in an amount of less than 5.0 parts by weight based on the total weight of the curable composition. [ka]

[0009] (In formula (1), A represents an n-valent organic group containing a sulfur atom, n represents an integer of 3 or more, and R represents a hydrogen atom or a methyl group. Each R may be the same or different.)

[0010] The present invention [2] further includes the curable composition according to the above [1], which contains a compound represented by the following formula (2):

[0011] [ka]

[0012] (In formula (2), A and R are defined as A and R in formula (1). X represents a single bond or a carbonyl group. R' represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an araliphatic hydrocarbon group. m represents an integer of 1 or more. l represents an integer of 1 or more. The sum of m and l represents n in formula (1). When a formula contains multiple Xs, each X may be the same as or different from another. When a formula contains multiple R's, each R' may be the same as or different from another.)

[0013] The present invention [3] further includes the curable composition according to the above [2], which contains a compound represented by the following formula (3):

[0014] [ka]

[0015] (In formula (3), A and n have the same meanings as A and n in formula (1). In formula (3), X and R' have the same meanings as X and R' in formula (2).)

[0016] The present invention [4] includes the curable composition according to any one of the above [1] to [3], wherein A in formula (1) is represented by the following formula (4).

[0017] [ka]

[0018] (In formula (4), the wavy line indicates the bonding position to the thio(meth)acryloyl group in formula (1).)

[0019] The present invention [5] includes a pressure-sensitive adhesive containing a cured product of the curable composition according to any one of the above [1] to [4]. [Effects of the Invention]

[0020] The curable composition of the present invention contains the compound represented by the above formula (1) in a predetermined ratio, and therefore, the above curable composition can prevent the pressure-sensitive adhesive from becoming cloudy.

[0021] The pressure-sensitive adhesive of the present invention contains the cured product of the curable composition, and therefore can suppress cloudiness. DETAILED DESCRIPTION OF THE INVENTION

[0022] 1.Curable composition The curable composition is a raw material composition for obtaining a pressure-sensitive adhesive (described later). The curable composition contains a (meth)acrylic resin and an additive. In the (meth)acrylic resin, (meth)acrylic refers to acrylic and / or methacrylic. The (meth)acrylic resin and the additive will be described in detail below.

[0023] 1) (Meth)acrylic resin The (meth)acrylic resin may be, for example, a polymer of a polymerization component, which contains, for example, a (meth)acrylic acid monoalkyl ester.

[0024] Examples of (meth)acrylic acid monoalkyl esters include alkyl (meth)acrylates, aromatic ring-containing (meth)acrylates, alicyclic ring-containing (meth)acrylates, and heterocyclic ring-containing (meth)acrylates.

[0025] Examples of alkyl (meth)acrylates include ethyl (meth)acrylate, butyl (meth)acrylate (B(M)A), 2-ethylhexyl (meth)acrylate (2EH(M)A), nonyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, and isostearyl (meth)acrylate. These can be used alone or in combination of two or more. Preferred are butyl (meth)acrylate (B(M)A) and 2-ethylhexyl (meth)acrylate (2EH(M)A).

[0026] Examples of aromatic ring-containing (meth)acrylates include benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, (o, m, or p-)phenoxybenzyl (meth)acrylate (POB-(M)A), 2-hydroxy-3-phenoxypropyl (meth)acrylate, nonylphenoxyethyl tetrahydrofurfuryl (meth)acrylate, and 1-naphthylmethyl (meth)acrylate (NMT-(M)A). These can be used alone or in combination of two or more. Preferred are (o, m, or p-)phenoxybenzyl (meth)acrylate (POB-(M)A) and 1-naphthylmethyl (meth)acrylate (NMT-(M)A).

[0027] Examples of alicyclic (meth)acrylates include cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. These can be used alone or in combination of two or more.

[0028] Examples of heterocycle-containing (meth)acrylates include tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, and caprolactone-modified tetrahydrofurfuryl (meth)acrylate, which can be used alone or in combination of two or more.

[0029] These can be used alone or in combination of two or more. From the viewpoint of obtaining excellent adhesiveness and optical properties, the (meth)acrylic acid monoalkyl ester is preferably an alkyl (meth)acrylate or an aromatic ring-containing (meth)acrylate, more preferably butyl (meth)acrylate (B(M)A), 2-ethylhexyl (meth)acrylate (2EH(M)A), (o, m, or p-)phenoxybenzyl (meth)acrylate (POB-(M)A), and 1-naphthylmethyl (meth)acrylate (NMT-(M)A). The (meth)acrylic acid monoalkyl ester is even more preferably an aromatic ring-containing (meth)acrylate, particularly preferably (o, m, or p-)phenoxybenzyl (meth)acrylate (POB-(M)A) and 1-naphthylmethyl (meth)acrylate (NMT-(M)A).

[0030] The type and content of the (meth)acrylic acid monoalkyl ester are appropriately adjusted within the range in which a pressure-sensitive adhesive can be obtained. For example, the content of the (meth)acrylic acid monoalkyl ester is, for example, 50 to 100 parts by mass, preferably 70 to 99.9 parts by mass, and more preferably 90 to 99 parts by mass, per 100 parts by mass of the total amount of the polymerization components.

[0031] Furthermore, examples of the polymerization component include copolymerizable monomers that are copolymerizable with the (meth)acrylic acid monoalkyl ester.

[0032] Examples of copolymerizable monomers include functional group-containing vinyl monomers, vinyl esters, aromatic vinyl monomers, N-substituted unsaturated carboxylic acid amides, heterocyclic vinyl compounds, vinylidene halide compounds, α-olefins, and dienes.

[0033] Examples of functional group-containing vinyl monomers include carboxyl group-containing vinyl monomers, hydroxyl group-containing vinyl monomers, amino group-containing vinyl monomers, glycidyl group-containing vinyl monomers, cyano group-containing vinyl monomers, sulfonic acid group-containing vinyl monomers and their salts, acetoacetoxy group-containing vinyl monomers, phosphoric acid group-containing compounds, and amide group-containing vinyl monomers. Examples of carboxyl group-containing vinyl monomers include (meth)acrylic acid ((M)AA), maleic anhydride, maleic acid, fumaric acid, itaconic acid, and crotonic acid. A preferred example of a carboxyl group-containing vinyl monomer is acrylic acid. Examples of hydroxyl group-containing vinyl monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate (4HB(M)A). Examples of amino group-containing vinyl monomers include 2-aminoethyl (meth)acrylate, 2-(N-methylamino)ethyl (meth)acrylate, and 2-(N,N-dimethylamino)ethyl (meth)acrylate. Examples of glycidyl group-containing vinyl monomers include glycidyl (meth)acrylate. Examples of cyano group-containing vinyl monomers include (meth)acrylonitrile. Examples of sulfonic acid group-containing vinyl monomers include allyl sulfonic acid, methallyl sulfonic acid, and salts thereof. Examples of acetoacetoxy group-containing vinyl monomers include acetoacetoxyethyl (meth)acrylate. Examples of phosphate group-containing compounds include 2-methacryloyloxyethyl acid phosphate. Examples of amide group-containing vinyl monomers include (meth)acrylamide. These can be used alone or in combination of two or more.

[0034] Examples of vinyl esters include vinyl acetate and vinyl propionate. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, and divinylbenzene. Examples of N-substituted unsaturated carboxylic acid amides include N-methylol (meth)acrylamide. Examples of heterocyclic vinyl compounds include vinylpyrrolidone. Examples of vinylidene halide compounds include vinylidene chloride and vinylidene fluoride. Examples of α-olefins include ethylene and propylene. Examples of dienes include butadiene.

[0035] Furthermore, the copolymerizable monomer may be a crosslinkable vinyl monomer. Examples of the crosslinkable vinyl monomer include compounds containing two or more vinyl groups. Examples of the compounds containing two or more vinyl groups include polyfunctional (meth)acrylates.

[0036] Examples of polyfunctional (meth)acrylates include difunctional (meth)acrylates and trifunctional or higher functional (meth)acrylates.

[0037] Examples of bifunctional (meth)acrylates include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, acrylate, pentaerythritol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate-di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and bisphenol A di(meth)acrylate. These can be used alone or in combination of two or more.

[0038] Examples of trifunctional or higher functional (meth)acrylates include trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and dipentaerythritol-poly(meth)acrylate. These can be used alone or in combination of two or more.

[0039] Further, examples of crosslinkable vinyl monomers include allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy poly(meth)acrylate, polyester poly(meth)acrylate, urethane poly(meth)acrylate, butyl diol poly(meth)acrylate, hexyl diol poly(meth)acrylate, methylene bis(meth)acrylamide, and polyethylene glycol chain-containing di(meth)acrylate. These can be used alone or in combination of two or more.

[0040] The copolymerizable monomers can be used alone or in combination of two or more. As the copolymerizable monomer, preferably, a functional group-containing vinyl monomer is used, more preferably, a carboxy group-containing vinyl monomer and a hydroxy group-containing vinyl monomer are used, and even more preferably, (meth)acrylic acid ((M)AA) and 4-hydroxybutyl (meth)acrylate (4HB(M)A) are used. As the copolymerizable monomer, more preferably, a hydroxy group-containing vinyl monomer is used, and particularly preferably, 4-hydroxybutyl (meth)acrylate (4HB(M)A) is used.

[0041] The type and content of the copolymerizable monomer are appropriately adjusted within the range that allows the preparation of a pressure-sensitive adhesive. For example, the content of the copolymerizable monomer is, for example, 0 to 50 parts by mass, preferably 0.1 to 30 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of the total amount of the polymerization components.

[0042] The method for producing the (meth)acrylic resin is not particularly limited. For example, the (meth)acrylic resin can be obtained by radically polymerizing the above-mentioned polymerization components by a known method.

[0043] In radical polymerization, for example, polymerization components and a polymerization initiator are blended in a solvent and mixed in the solvent. Examples of solvents include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ketones, and alkyl esters, preferably aromatic hydrocarbons. Examples of aromatic hydrocarbons include toluene and xylene, preferably toluene. Examples of polymerization initiators include persulfates, organic peroxides, and azo compounds. Examples of azo compounds include azoisobutyronitrile (AIBN). These can be used alone or in combination of two or more. The blending ratio of the polymerization initiator is appropriately set depending on the purpose and application.

[0044] In radical polymerization, a molecular weight modifier can be blended as needed. Examples of molecular weight modifiers include mercaptans, allyl compounds, and low molecular weight halogen compounds. These can be used alone or in combination of two or more. The blending ratio of the molecular weight modifier is appropriately set depending on the purpose and application.

[0045] The polymerization conditions are not particularly limited. For example, under normal pressure, the polymerization temperature is, for example, 30 to 150° C., preferably 50 to 100° C. The polymerization time is, for example, 1 to 30 hours, preferably 2 to 20 hours.

[0046] The above radical polymerization polymerizes the polymerization components to obtain a (meth)acrylic resin. That is, the (meth)acrylic resin is a polymer of the above polymerization components. When the above polymerization components are polymerized in the presence of a solvent, the above radical polymerization produces a solution of the (meth)acrylic resin. The solution of the (meth)acrylic resin is subjected to a solvent removal treatment, if necessary.

[0047] The (meth)acrylic resin is mixed with the additives by a known method, and the amount of the (meth)acrylic resin will be described later.

[0048] 2) Additives [i] A compound represented by formula (1) The additive contains a compound represented by the following formula (1) as an essential component. In other words, the curable composition contains a compound represented by the following formula (1) as an additive. The compound represented by the following formula (1) is a crosslinking agent.

[0049] [ka]

[0050] (In formula (1), A represents an n-valent organic group containing a sulfur atom, n represents an integer of 3 or more, and R represents a hydrogen atom or a methyl group. Each R may be the same or different.)

[0051] The compound represented by the above formula (1) has n thio(meth)acryloyl groups. (Meth)acryloyl refers to acryloyl and / or methacryloyl. The above formula (1) will be described in detail below.

[0052] <Aおよびn> In the above formula (1), A represents an n-valent organic group containing a sulfur atom, and n is the valence of the organic group A.

[0053] n represents an integer of 3 or greater. More specifically, n represents, for example, an integer of 3 or greater and 15 or less, preferably an integer of 3 or greater and 8 or less, more preferably an integer of 3 or greater and 6 or less, even more preferably 3 or 4, and particularly preferably 3.

[0054] The organic group A is an atomic group bonded to the thio(meth)acryloyl group of formula (1). Examples of the organic group A include residues of n-functional thiols. More specifically, examples of the organic group A include residues obtained by removing mercapto groups from trifunctional or higher sulfur-containing polythiols (hereinafter referred to as trifunctional or higher sulfur-containing polythiol residues).

[0055] A tri- or higher functional sulfur-containing polythiol is an organic compound containing three or more mercapto groups in one molecule and one or more (preferably two or three) sulfur atoms other than the mercapto groups. Examples of tri- or higher functional sulfur-containing polythiols include sulfur-containing trithiol, sulfur-containing tetrathiol, sulfur-containing pentathiol, sulfur-containing hexathiol, and sulfur-containing octathiol.

[0056] Sulfur-containing trithiol is a trifunctional thiol containing a sulfur atom in addition to a mercapto group. Examples of sulfur-containing trithiol include 1,2,3-tris(mercaptomethylthio)propane, 1,2,3-tris(2-mercaptoethylthio)propane, 1,2,3-tris(3-mercaptopropylthio)propane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST), 2,2-bis(mercaptomethylthio)ethanethiol, 3-mercaptomethylthio-1,7-dimercapto-2,6-dithiaheptane, 3-mercaptomethylthio-1,6-dimercapto-2,5-dithiahexane, 4,6-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio] ]-6-[4-(6-mercaptomethylthio)-1,3-dithianylthio]-1,3-dithiane, tris(mercaptomethylthio)methane, tris(mercaptoethylthio)methane, 2,4,6-tris(mercaptomethylthio)-1,3,5-trithiacyclohexane, tris[(4-mercaptomethyl-2,5-dithiacyclohexyl-1-yl)methylthio]methane, 4-mercaptomethyl-2-(2,3-dimercaptopropylthio)-1,3-dithiacyclopentane, and 4-mercaptomethyl-2-(1,3-dimercapto-2-propylthio)-1,3-dithiacyclopentane.

[0057] The sulfur-containing tetrathiol is a tetrafunctional thiol containing a sulfur atom in addition to a mercapto group. Examples of sulfur-containing tetrathiols include 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (FSH), 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, tetrakis(mercaptomethylthiomethyl)methane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, bis(2, 3-dimercaptopropyl) sulfide, thiodipropionic acid bis(2,3-dimercaptopropyl ester), dithiodiglycolic acid bis(2,3-dimercaptopropyl ester), thiodipropionic acid bis(2,3-dimercaptopropyl ester), dithiodipropionic acid bis(2,3-dimercaptopropyl ester), 1,1,3,3-tetrakis(mercaptomethylthio)propane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 1,1,5,5-tetrakis(mercaptomethylthio)- 3-Thiapentane, 1,1,6,6-tetrakis(mercaptomethylthio)-3,4-dithiahexane, 2,5-bis(4,4-bis(mercaptomethylthio)-2-thiabutyl)-1,4-dithiane, 2,2-bis(mercaptomethylthio)-1,3-propanedithiol, 3,6-bis(mercaptomethylthio)-1,9-dimercapto-2,5,8-trithianonane, 4-[3,5-bis(mercaptomethylthio)-7-mercapto-2,6-dithiaheptylthio]-6-mercaptomethylthio-1,3-dithiane , 1,1-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio]-1,3-bis(mercaptomethylthio)propane, 3-[2-(1,3-dithietanyl)]methyl-7,9-bis(mercaptomethylthio)-1,11-dimercapto-2,4,6,10-tetrathiaundecane, 4-[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio]-5-mercaptomethylthio-1,3-dithiolane, 2-[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio]mercaptomethylthiomethyl-1,3-dithietane, 4-{1-[2-(1,3-dithietanyl)]-3-mercapto-2-thiapropylthio}-5-[1,2-bis(mercaptomethylthio)-4-mercapto-3-thiabutylthio]-1,3-dithiolane, 1,1,5,5-tetrakis(mercaptomethylthio)-2,4-dithiapentane, and 1,1,3,3-tetrakis(mercaptomethylthio)-2-thiapropane.

[0058] The sulfur-containing pentathiol is a pentafunctional thiol containing a sulfur atom in addition to a mercapto group. Examples of sulfur-containing pentathiols include 1-[4-(6-mercaptomethylthio)-1,3-dithianylthio]-3-[2,2-bis(mercaptomethylthio)ethyl]-7,9-bis(mercaptomethylthio)-2,4,6,10-tetrathiaundecane and bis[4,4-bis(mercaptomethylthio)-1,3-dithiabutyl]-(mercaptomethylthio)methane.

[0059] Sulfur-containing hexathiol is a hexafunctional thiol containing a sulfur atom in addition to a mercapto group. Examples of sulfur-containing hexathiol include 1,1,9,9-tetrakis(mercaptomethylthio)-5-(3,3-bis(mercaptomethylthio)-1-thiapropyl)3,7-dithianonane, tris(2,2-bis(mercaptomethylthio)ethyl)methane, tris(4,4-bis(mercaptomethylthio)-2-thiabutyl)methane, 3,5,9,11-tetrakis(mercaptomethylthio)-1,13-dimercapto-2,6,8,12-tetrathiatridecane, 3,4,8 ...methane, 3,4,8,9-tetrakis(mercaptomethylthio)-5-(3,3-bis(mercaptomethylthio)-1-thiapropyl)methane, 3,4,8,9-tetrakis(mercaptomethylthio)-5-(3,3-bis(mercaptomethylthio)-1-thiapropyl)methane, 3,4,8,9-tetrakis(mercaptomethylthio)-5-(3,3-bis(mercaptomethylthio)-1-thiapropyl) methylthio)-1,11-dimercapto-2,5,7,10-tetrathiaundecane, 4,6-bis[3,5-bis(mercaptomethylthio)-7-mercapto-2,6-dithiaheptylthio]-1,3-dithiane, 3-[2-(1,3-dithietanyl)]methyl-7,9,13,15-tetrakis(mercaptomethylthio)-1,17-dimercapto-2,4,6,10,12,16-hexathiaheptadecane, 4-[3,4,8,9-tetrakis(mercaptomethylthio)-11-mercapto-2,5,7,10 -tetrathiaundecyl]-5-mercaptomethylthio-1,3-dithiolane, 4,5-bis[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio]-1,3-dithiolane, 4-[3-bis(mercaptomethylthio)methyl-5,6-bis(mercaptomethylthio)-8-mercapto-2,4,7-trithiaoctyl]-5-mercaptomethylthio-1,3-dithiolane, 2-{bis[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio] methyl}-1,3-dithietane, 2-[3,4,8,9-tetrakis(mercaptomethylthio)-11-mercapto-2,5,7,10-tetrathiaundecylthio]mercaptomethylthiomethyl-1,3-dithietane, 2-[3-bis(mercaptomethylthio)methyl-5,6-bis(mercaptomethylthio)-8-mercapto-2,4,7-trithiaoctyl]mercaptomethylthiomethyl-1,3-dithietane, tris[4,4-bis(mercaptomethylthio)-1,3-dithiabutyl]methane, tris[2,2-bis(mercaptomethylthio)-2-thiapropyl]methane, tris[4,4-bis(mercaptomethylthio)-3-thiabutyl]methane, and 2,4,6-tris[3,3-bis(mercaptomethylthio)-2-thiapropyl]-1,3,5-trithiacyclohexane.

[0060] Sulfur-containing octathiols are octafunctional thiols containing sulfur atoms in addition to mercapto groups. Examples of sulfur-containing octathiols include tetrakis(4,4-bis(mercaptomethylthio)-2-thiabutyl)methane, 3,5,9,11,15,17-hexakis(mercaptomethylthio)-1,19-dimercapto-2,6,8,12,14,18-hexathianonadecane, 9-(2,2-bis(mercaptomethylthio)ethyl)-3,5,13,15-tetrakis(mercaptomethylthio)-1,17-dimercapto-2,6,8,10,12,16-hexathiaheptadecane, and tetrakis(2,2 -bis(mercaptomethylthio)ethyl)methane, 3,4,8,9,13,14-hexakis(mercaptomethylthio)-1,16-dimercapto-2,5,7,10,12,15-hexathiahexadecane, 8-[bis(mercaptomethylthio)methyl]-3,4,12,13-tetrakis(mercaptomethylthio)-1,15-dimercapto-2,5,7,9,11,14-hexathiapentadecane, and tetrakis[3,3-bis(mercaptomethylthio)-2-thiapropyl]methane.

[0061] The tri- or higher functional sulfur-containing polythiol residue preferably includes a tri- to hexafunctional sulfur-containing polythiol residue, more preferably a tri- or tetrafunctional sulfur-containing polythiol residue, and even more preferably a trifunctional sulfur-containing polythiol residue.

[0062] That is, in formula (1), A is preferably a trifunctional to hexafunctional sulfur-containing polythiol residue, more preferably a trifunctional to tetrafunctional sulfur-containing polythiol residue, and even more preferably a trifunctional sulfur-containing polythiol residue.

[0063] In other words, A is preferably a trivalent to hexavalent organic group containing one or more sulfur atoms, more preferably a trivalent organic group containing one or more sulfur atoms, or a tetravalent organic group containing one or more sulfur atoms, and even more preferably a trivalent organic group containing one or more sulfur atoms.

[0064] The trivalent organic group (organic group A (n=3)) containing one or more sulfur atoms is preferably a residue obtained by removing a mercapto group from the above-mentioned sulfur-containing trithiol, more preferably a residue obtained by removing a mercapto group from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST) (GST residue). The residue obtained by removing a mercapto group from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST) (GST residue) is represented, for example, by the following formula (4):

[0065] That is, A in the above formula (1) is preferably a GST residue represented by the following formula (4).

[0066] [ka]

[0067] (In formula (4), the wavy line indicates the bonding position to the thio(meth)acryloyl group in formula (1).)

[0068] In the above formula (4), the wavy line indicates the bonding position to the thio(meth)acryloyl group in formula (1). When A in the above formula (1) is a GST residue represented by the above formula (4), n in formula (1) is 3.

[0069] When A in the above formula (1) is a GST residue represented by the above formula (4), a cured resin product can be obtained that has particularly excellent refractive index and curability, as well as particularly excellent flexibility.

[0070] <r> In the above formula (1), R represents a hydrogen atom or a methyl group, preferably a hydrogen atom. R constitutes a thio(meth)acryloyl group in the above formula (1). More specifically, when R represents a hydrogen atom, the above formula (1) contains a thioacryloyl group (-SC(=O)CH=CH2). Furthermore, when R represents a methyl group, the above formula (1) contains a thiomethacryloyl group (-SC(=O)C(CH3)=CH2).

[0071] The compound represented by the above formula (1) has three or more thio(meth)acryloyl groups depending on the value of n. Preferably, the compound represented by the above formula (1) has three thio(meth)acryloyl groups. In the three or more thio(meth)acryloyl groups, each R may be the same as or different from each other. Preferably, each R is the same as each other.

[0072] From the viewpoint of obtaining excellent adhesiveness, preferably, all R in the above formula (1) represent hydrogen atoms. That is, the above formula (1) contains n thioacryloyl groups (—SC(═O)CH═CH).

[0073] <Example> A preferred example of the compound represented by the above formula (1) is a compound in which A is a GST residue. Examples of such compounds include compounds represented by the following formula (1-1):

[0074] [ka]

[0075] (In formula (1-1), R has the same meaning as R in formula (1). In formula (1-1), the portion surrounded by a dashed line represents the organic group A (n=3) in formula (1).)

[0076] In the above formula (1-1), thio(meth)acryloyl groups are bonded to all three bonds of the organic group A (GST residue) in the above formula (1). Hereinafter, the compound represented by the above formula (1-1) may be referred to as a trithio(meth)acryloyl-modified GST.

[0077] An example of a trithio(meth)acryloyl-modified GST is 1,8-bis(meth)acryloylthio-(4-(meth)acryloylthiomethyl-3,6-dithiaoctane) (GST(M)A). From the viewpoints of refractive index and flexibility, a preferred example of a trithio(meth)acryloyl-modified GST is 1,8-bisacryloylthio-(4-acryloylthiomethyl-3,6-dithiaoctane (GSTA).

[0078] The method for obtaining the compound represented by the formula (1) is not particularly limited. For example, the compound represented by the formula (1) is produced by modifying all mercapto groups of a sulfur-containing polythiol having three or more functional groups into thio(meth)acryloyl groups. In addition, the compound represented by the formula (1) can also be obtained as a commercially available product.

[0079] In particular, 1,8-bis(meth)acryloylthio-(4-(meth)acryloylthiomethyl-3,6-dithiaoctane) as the compound represented by the above formula (1) can be produced, for example, based on the description in JP-A-4-29967.

[0080] In addition, the compound represented by the formula (1) is produced as an additive composition (described later) together with a compound represented by the formula (2) (described later) and a compound represented by the formula (3) (described later) by the method described later.

[0081] The compound represented by the formula (1) is mixed with the (meth)acrylic resin by a known method. The amount of the compound represented by the formula (1) will be described later.

[0082] [ii] A compound represented by formula (2) The additive may contain, as an optional component, a compound represented by the following formula (2). The additive preferably contains a compound represented by the following formula (2). That is, the curable composition preferably contains a compound represented by the following formula (2).

[0083] [ka]

[0084] (In formula (2), A and R are defined as A and R in formula (1). X represents a single bond or a carbonyl group. R' represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an araliphatic hydrocarbon group. m represents an integer of 1 or more. l represents an integer of 1 or more. The sum of m and l represents n in formula (1). When a formula contains multiple Xs, each X may be the same as or different from another. When a formula contains multiple R's, each R' may be the same as or different from another.)

[0085] The compound represented by the formula (2) has m thio(meth)acryloyl groups. The compound represented by the formula (2) also has l SXR' groups. The formula (2) will be described in detail below.

[0086] In the above formula (2), A has the same meaning as A in the above formula (1). That is, in the above formula (2), A represents an n-valent organic group containing a sulfur atom. A is preferably a GST residue represented by the above formula (4).

[0087] <n> In the above formula (2), n has the same meaning as n in the above formula (1). That is, n is, for example, an integer of 3 or more and 15 or less, preferably an integer of 3 or more and 8 or less, more preferably an integer of 3 or more and 6 or less, even more preferably 3 or 4, and particularly preferably 3.

[0088] <r> In the above formula (2), R has the same meaning as R in the above formula (1). In the above formula (2), R represents a hydrogen atom or a methyl group, and preferably represents a hydrogen atom.

[0089] <x> In the above formula (2), X represents a single bond or a carbonyl group, and preferably represents a carbonyl group.

[0090] When X represents a single bond, S and R' are directly bonded in the above formula (2), that is, when X represents a single bond, the SXR' group in the above formula (2) represents an SR' group.

[0091] When X represents a carbonyl group, S and R' in the above formula (2) are indirectly bonded via the carbonyl group, i.e., when X represents a carbonyl group, the SXR' group in the above formula (2) represents an S(C=O)R' group.

[0092] The compound represented by the above formula (2) can have one or more SXR' groups depending on the values ​​of m and n. That is, the above formula (2) may contain one X or may contain multiple (two or more) Xs. When the above formula (2) contains multiple Xs, the Xs may be the same as or different from one another. Preferably, the Xs are the same as one another.

[0093] <R’> In the above formula (2), R' represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an araliphatic hydrocarbon group.

[0094] Examples of the aliphatic hydrocarbon group include aliphatic hydrocarbon groups having 1 to 20 carbon atoms. More specific examples of the aliphatic hydrocarbon group include linear aliphatic hydrocarbon groups having 1 to 20 carbon atoms and cyclic aliphatic hydrocarbon groups having 3 to 20 carbon atoms.

[0095] Examples of the linear aliphatic hydrocarbon group having 1 to 20 carbon atoms include a linear saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms and a linear unsaturated aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of the linear saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a 2-butyl group, a 1-pentyl group, a 2-pentyl group, a 3-pentyl group, a 2-methyl-1-butyl group, an isopentyl group, a tert-pentyl group, a 3-methyl-2-butyl group, a neopentyl group, an n-hexyl group, a 4- Examples of the alkyl group include methyl-2-pentyl, 1-heptyl, 3-heptyl, 1-octyl, 2-octyl, 2-ethyl-1-hexyl, 1,1-dimethyl-3,3-dimethylbutyl, 1-nonyl, 1-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl. Examples of the linear unsaturated aliphatic hydrocarbon group having 1 to 20 carbon atoms include vinyl and 2-propenyl. These groups can be used alone or in combination.

[0096] Examples of cyclic aliphatic hydrocarbon groups having 3 to 20 carbon atoms include saturated cyclic aliphatic hydrocarbon groups having 3 to 20 carbon atoms and unsaturated cyclic aliphatic hydrocarbon groups having 3 to 20 carbon atoms. Examples of saturated cyclic aliphatic hydrocarbon groups having 3 to 20 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl groups. Examples of unsaturated cyclic aliphatic hydrocarbon groups having 3 to 20 carbon atoms include cyclopentenyl and cyclohexenyl groups. These can be used alone or in combination of two or more.

[0097] Examples of aromatic hydrocarbon groups include aromatic hydrocarbon groups having 6 to 20 carbon atoms. Examples of aromatic hydrocarbon groups having 6 to 20 carbon atoms include phenyl, 2-tolyl, 3-tolyl, 4-tolyl, 2,3-xylyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 3,4-xylyl, 3,5-xylyl, 2,3,4-trimethylphenyl, 3,4,5-trimethylphenyl, 2,4,6-trimethylphenyl, 2,3,4,5-tetramethylphenyl, 2,3,4,6-tetramethylphenyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 1-naphthyl, and 2-naphthyl. These groups can be used alone or in combination of two or more.

[0098] Examples of aromatic aliphatic hydrocarbon groups include aromatic aliphatic hydrocarbon groups having 7 to 20 carbon atoms. Examples of aromatic aliphatic hydrocarbon groups having 7 to 20 carbon atoms include benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl, 2-phenylpropyl, 3-phenylpropyl, o-methylbenzyl, m-methylbenzyl, p-methylbenzyl, o-ethylbenzyl, m-ethylbenzyl, p-ethylbenzyl, o-isopropylbenzyl, m-isopropylbenzyl, p-isopropylbenzyl, 2,3,4-trimethylbenzyl, 3,4,5-trimethylbenzyl, and 2,4,6-trimethylbenzyl. These can be used alone or in combination of two or more.

[0099] The aliphatic hydrocarbon group, aromatic hydrocarbon group, and araliphatic hydrocarbon group may have a substituent. Examples of the substituent include a halogeno group, a cyano group, an amino group, a carboxy group, a sulfonyl group, and an alkoxy group. These may be used alone or in combination of two or more. The number of substituents is appropriately determined depending on the purpose and application. The substitution position is appropriately determined depending on the purpose and application.

[0100] The compound represented by the above formula (2) can have one or more SXR' groups depending on the values ​​of m and n. That is, the above formula (2) may contain one R' or may contain multiple (two or more) R'. When the above formula (2) contains multiple R', each R' may be the same as or different from each other. Preferably, each R' is the same as each other.

[0101] When R' represents an aliphatic hydrocarbon group, it is preferably a linear aliphatic hydrocarbon group having 1 to 10 carbon atoms, more preferably a linear aliphatic hydrocarbon group having 1 to 4 carbon atoms, even more preferably a linear aliphatic hydrocarbon group having 1 to 2 carbon atoms, and particularly preferably a methyl group.

[0102] When R' represents an aromatic hydrocarbon group, it is preferably an aromatic hydrocarbon group having 6 to 10 carbon atoms, more preferably an aromatic hydrocarbon group having 6 to 8 carbon atoms, and even more preferably a phenyl group.

[0103] When R' represents an aromatic aliphatic hydrocarbon group, it is preferably an aromatic aliphatic hydrocarbon group having 7 to 15 carbon atoms, more preferably an aromatic hydrocarbon group having 7 to 10 carbon atoms, and even more preferably a benzyl group.

[0104] From the viewpoint of refractive index and adhesiveness, in the above formula (1), R' more preferably represents a methyl group or a phenyl group, and particularly preferably represents a methyl group. That is, as SXR' in the above formula (1), more preferably, an acetylthio group (-SC(=O)CH3) and a benzoylthio group (-S(C=O)CH6) are 12 ), and particularly preferably an acetylthio group (—SC(═O)CH3).

[0105] <m> In the above formula (2), m is the number of thio(meth)acryloyl groups in one molecule of the above compound. m represents an integer of 1 or more. More specifically, m represents, for example, an integer of 1 or more and 10 or less, preferably an integer of 1 or more and 8 or less, more preferably an integer of 1 or more and 4 or less, and even more preferably an integer of 1 or more and 3 or less.

[0106] <l> In the above formula (2), l is the number of SXR' groups in one molecule of the above compound. l represents an integer of 1 or more. More specifically, l represents, for example, an integer of 1 or more and 10 or less, preferably an integer of 1 or more and 8 or less, more preferably an integer of 1 or more and 4 or less, and even more preferably an integer of 1 or more and 3 or less.

[0107] <m+l> In the above formula (2), the sum of m and l represents n in formula (1). That is, the sum of m and l represents an integer of 3 or greater. The sum of m and l represents, for example, an integer of 3 or greater and 15 or less, preferably an integer of 3 or greater and 8 or less, more preferably an integer of 3 or greater and 6 or less, even more preferably 3 or 4, and particularly preferably 3.

[0108] In the above formula (2), when l is 1, m represents an integer of 2 or more. In such a case, the compound represented by the above formula (2) has two or more thio(meth)acryloyl groups. When the compound represented by the above formula (2) has two or more thio(meth)acryloyl groups, the compound represented by the above formula (2) is a crosslinking agent.

[0109] In the above formula (2), when m is 1, l represents an integer of 2 or more. In such a case, the compound represented by the above formula (2) has one thio(meth)acryloyl group. When the compound represented by the above formula (2) has one or more thio(meth)acryloyl groups, the compound represented by the above formula (2) is not a crosslinking agent.

[0110] <Example> The compound represented by the above formula (2) preferably includes a compound having a GST residue as the organic group A. Examples of such a compound include a compound represented by the following formula (2-1) and a compound represented by the following formula (2-2).

[0111] [ka]

[0112] (In formula (2-1), R has the same meaning as R in formula (1). X and R' have the same meaning as X and R' in formula (2). In formula (2-1), the part surrounded by a dashed line represents the organic group A in formula (1).)

[0113] [ka]

[0114] (In formula (2-2), R has the same meaning as R in formula (1). X and R' have the same meaning as X and R' in formula (2). In formula (2-2), the part surrounded by a dashed line represents the organic group A in formula (1).)

[0115] In the above formula (2-1), of the three bonds of the organic group A (GST residue), two bonds are bonded to SXR' groups (i.e., l = 2), and one bond is bonded to a thio(meth)acryloyl group (i.e., m = 1). Hereinafter, the compound represented by the above formula (2-1) may be referred to as a monothio(meth)acryloyl-modified GST.

[0116] In the above formula (2-2), of the three bonds of the organic group A (GST residue), one bond is bonded to an SXR' group (i.e., l = 1), and the other two bonds are bonded to thio(meth)acryloyl groups (i.e., m = 2). Hereinafter, the compound represented by the above formula (2-2) may be referred to as a dithio(meth)acryloyl-modified GST.

[0117] The method for obtaining the compound represented by formula (2) is not particularly limited. For example, the compound represented by formula (2) is produced as an additive composition (described later) together with the compound represented by formula (1) and the compound represented by formula (3) (described later) by the method described later.

[0118] The compound represented by the formula (2) is mixed with the (meth)acrylic resin by a known method. The amount of the compound represented by the formula (2) will be described later.

[0119] [iii] A compound represented by formula (3) The additive may contain, as an optional component, a compound represented by the following formula (3). The additive preferably contains a compound represented by the following formula (3). That is, the curable composition preferably contains a compound represented by the following formula (3).

[0120] [ka] (In formula (3), A and n have the same meanings as A and n in formula (1). In formula (3), X and R' have the same meanings as X and R' in formula (2).)

[0121] The compound represented by the above formula (3) has n SXR' groups. The above formula (3) will be described in detail below.

[0122] < / l> < / m> < / x> < / r> < / n> In the above formula (3), A has the same meaning as A in the above formula (1). That is, in the above formula (3), A represents an n-valent organic group containing a sulfur atom. A is preferably a GST residue represented by the above formula (4).

[0123] <n> In the above formula (3), n has the same meaning as n in the above formula (1). That is, n is, for example, an integer of 3 or more and 15 or less, preferably an integer of 3 or more and 8 or less, more preferably an integer of 3 or more and 6 or less, even more preferably 3 or 4, and particularly preferably 3.

[0124] <x> In the above formula (3), X has the same meaning as X in the above formula (2). That is, X represents a single bond or a carbonyl group, and preferably represents a carbonyl group.

[0125] <R’> In the above formula (3), R' has the same meaning as R' in the above formula (2). That is, R' represents the above aliphatic hydrocarbon group, the above aromatic hydrocarbon group, or the above araliphatic hydrocarbon group, preferably represents a methyl group or a phenyl group, and particularly preferably represents a methyl group.

[0126] <Example> A preferred example of the compound represented by the above formula (3) is a compound in which A is a GST residue. Examples of such compounds include compounds represented by the following formula (3-1):

[0127] [ka]

[0128] (In formula (3-1), X and R' have the same meanings as X and R' in formula (2). In formula (3-1), the part surrounded by a dashed line represents the organic group A in formula (1).)

[0129] In the above formula (3-1), SXR' groups are bonded to all three bonds of the organic group A (GST residue). Hereinafter, the compound represented by the above formula (3-1) may be referred to as an unmodified thio(meth)acryloyl GST.

[0130] The method for obtaining the compound represented by the formula (3) is not particularly limited. For example, the compound represented by the formula (3) is produced as an additive composition (described later) together with the compound represented by the formula (1) and the compound represented by the formula (2) by the method described later.

[0131] The compound represented by the formula (3) is mixed with the (meth)acrylic resin by a known method. The amount of the compound represented by the formula (3) will be described later.

[0132] [iv] Additive composition The method for obtaining the compounds represented by the above formulas (1) to (3) is not particularly limited. For example, the compound represented by the above formula (1), the compound represented by the above formula (2), and the compound represented by the above formula (3) can be produced in accordance with the method described in WO 2024 / 101258.

[0133] More specifically, the additive composition is produced by the following method: The additive composition contains the compound represented by the above formula (1), the compound represented by the above formula (2), and the compound represented by the above formula (3).

[0134] The additive composition is synthesized, for example, by reacting a polythiol with a first modifying agent to form an SXR' group and a second modifying agent to form a thio(meth)acryloyl group.

[0135] <Polythiol> The polythiol may be the above-mentioned tri- or higher functional sulfur-containing polythiol, i.e., a polythiol having n valences (n is an integer of 3 or more) and containing a sulfur atom.

[0136] More specifically, examples of polythiols include the sulfur-containing trithiol, sulfur-containing tetrathiol, sulfur-containing pentathiol, sulfur-containing hexathiol, and sulfur-containing octathiol.From the viewpoint of availability and reactivity, the polythiol preferably includes the sulfur-containing trithiol.From the viewpoint of availability and reactivity, the sulfur-containing trithiol is more preferably 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST).

[0137] <First denaturant> The first modifying agent is a compound that caps the molecular terminals of the polythiol and does not form (meth)acryloyl groups. In other words, the first modifying agent is a compound that modifies the mercapto groups of the trifunctional or higher sulfur-containing polythiol into SXR' groups.

[0138] An example of the first modifying agent is a compound represented by the following formula (5).

[0139] [ka]

[0140] (In formula (5), X and R' have the same meanings as X and R' in formula (2). Y represents a halogen or a hydroxyl group.)

[0141] In the above formula (5), X and R' have the same meanings as X and R' in formula (2). Y represents a halogen or a hydroxyl group. Examples of halogen include fluorine, chlorine, bromine, and iodine. Preferred examples of halogen include chlorine and bromine.

[0142] In the above formula (5), when Y is a halogen and X is a single bond, examples of the first modifying agent include halogenated hydrocarbons. Examples of the first modifying agent include alkyl halides, aryl halides, and aralkyl halides. Examples of the alkyl halides include methyl fluoride, methyl chloride, methyl bromide, methyl iodide, ethyl fluoride, ethyl chloride, ethyl bromide, and ethyl iodide. Examples of the aryl halides include phenyl fluoride, phenyl chloride, phenyl bromide, and phenyl iodide. Examples of the aralkyl halides include benzyl fluoride, benzyl chloride, benzyl bromide (benzyl bromide), and benzyl iodide. These may be used alone or in combination of two or more. Examples of the first modifying agent include aralkyl halides, and more preferably benzyl bromide (benzyl bromide).

[0143] In the above formula (5), when Y is a halogen and X is a carbonyl group, the first modifying agent may be an acyl halide. Examples of acyl halide include acetyl fluoride, acetyl chloride, acetyl bromide, acetyl iodide, benzoyl fluoride, benzoyl chloride, phenylacetyl chloride (phenylacetyl chloride), phenylpropionyl chloride (phenylpropionyl chloride), benzoyl bromide, and benzoyl iodide. These may be used alone or in combination of two or more. Preferred examples of the first modifying agent include benzoyl chloride, phenylacetyl chloride (phenylacetyl chloride), and phenylpropionyl chloride (phenylpropionyl chloride).

[0144] In the above formula (5), when Y is a hydroxyl group and X is a carbonyl group, the first modifying agent may be a carboxylic acid. Examples of the carboxylic acid include monocarboxylic acids and their anhydrides. Examples of the monocarboxylic acid include aliphatic monocarboxylic acids, aromatic monocarboxylic acids, and araliphatic monocarboxylic acids. Examples of the aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, caproic acid, octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 2-ethylhexanoic acid, cyclohexanecarboxylic acid, and cyclopentanecarboxylic acid. Examples of the aromatic monocarboxylic acids include benzoic acid and toluic acid. Examples of the araliphatic monocarboxylic acids include diphenylacetic acid. These may be used alone or in combination of two or more. Preferably, the first modifying agent includes aliphatic monocarboxylic acids and their anhydrides, more preferably acetic acid and its anhydrides, and even more preferably acetic anhydride.

[0145] <Second denaturant> The second modifying agent is a compound that caps the molecular terminals of the polythiol to form (meth)acryloyl groups. In other words, the second modifying agent is a compound that modifies the mercapto groups of the trifunctional or higher sulfur-containing polythiol to thio(meth)acryloyl groups.

[0146] Examples of the second modifying agent include (meth)acrylic acid halides and (meth)acrylic acid anhydrides. Examples of the (meth)acrylic acid halides include (meth)acrylic acid chloride, (meth)acrylic acid bromide, and (meth)acrylic acid iodide. Examples of the (meth)acrylic acid anhydrides include acrylic acid anhydride and methacrylic acid anhydride. These can be used alone or in combination of two or more.

[0147] Furthermore, as the second modifying agent, two or more compounds can be used in combination so as to be able to form a (meth)acryloyl group.

[0148] More specifically, the second modifying agent may contain, for example, (meth)acrylic acid and a dehydration condensation agent. Examples of the dehydration condensation agent include imidazole-based condensation agents, triazine-based condensation agents, phosphonium-based condensation agents, uronium-based condensation agents, and haluronium-based condensation agents. These may be used alone or in combination of two or more.

[0149] The second modifying agent may contain, for example, a propionic acid derivative and a basic compound. Examples of the propionic acid derivative include those described in Japanese Patent Laid-Open Publication No. 4-29967. More specific examples of the propionic acid derivative include β-chloropropionic acid, β-bromopropionic acid, β-hydroxypropionic acid toluenesulfonyl ester, β-hydroxypropionic acid benzenesulfonyl ester, β-hydroxypropionic acid methanesulfonyl ester, α-methyl-β-chloropropionic acid, α-methyl-β-bromopropionic acid, α-methyl-β-hydroxypropionic acid toluenesulfonyl ester, α-methyl-β-hydroxypropionic acid benzenesulfonyl ester, α-methyl-β-hydroxypropionic acid methanesulfonyl ester, and acid halides thereof. More specifically, acid halides include β-chloropropionic acid chloride (3-chloropropionic acid chloride), β-bromopropionic acid chloride, α-methyl-β-chloropropionic acid chloride, and α-methyl-β-bromopropionic acid chloride. These can be used alone or in combination of two or more. Bases include, for example, sodium hydroxide, potassium hydroxide, triethylamine, and pyridine. These can be used alone or in combination of two or more.

[0150] <Mixing ratio and reaction conditions> In the production of the additive composition, first, a trifunctional or higher sulfur-containing polythiol, a first modifier, and a second modifier are mixed as reaction raw materials in an appropriate ratio. Then, these reaction raw materials are reacted under appropriate conditions. The reaction method, reaction order, and reaction conditions are appropriately set depending on the type of reaction raw materials.

[0151] More specifically, in this method, first, the tri- or higher functional sulfur-containing polythiol is prepared (preparation step), and then, the tri- or higher functional sulfur-containing polythiol is reacted with a first modifying agent and a second modifying agent (reaction step).

[0152] In the reaction step, the order of reaction of the first modifier and the second modifier is not particularly limited. For example, a trifunctional or higher sulfur-containing polythiol may be simultaneously reacted with the first modifier and the second modifier. Alternatively, a trifunctional or higher sulfur-containing polythiol may be reacted with the first modifier first, and then the reaction product may be reacted with the second modifier. Alternatively, a trifunctional or higher sulfur-containing polythiol may be reacted with the second modifier first, and then the reaction product may be reacted with the first modifier.

[0153] From the viewpoint of productivity and reactivity, it is preferable to first react a tri- or higher functional sulfur-containing polythiol with the first modifier, and then react the reaction product with the second modifier.

[0154] That is, preferably, a tri- or higher functional sulfur-containing polythiol is first modified with a first modifying agent to add an SXR′ group to the organic group A. Thereafter, the reaction product is modified with a second modifying agent to add a thio(meth)acryloyl group to the organic group A.

[0155] More specifically, in the reaction step, first, the above-mentioned tri- or higher functional sulfur-containing polythiol is reacted with the above-mentioned first modifying agent by an appropriate method (first reaction step).

[0156] The formulation, reaction method and reaction conditions in the first reaction step are appropriately selected depending on, for example, the type of the first modifying agent.

[0157] Examples of the reaction between a tri- or higher functional sulfur-containing polythiol and a first modifying agent include a nucleophilic substitution reaction, a nucleophilic acylation reaction, a cross-coupling reaction, and a dehydration condensation reaction.

[0158] For example, when the first modifier contains a halogenated hydrocarbon, a trifunctional or higher sulfur-containing polythiol and the first modifier undergo a nucleophilic substitution reaction in the presence of a known basic compound to produce a compound represented by formula (1). More specifically, the basic compound eliminates protons from the trifunctional or higher sulfur-containing polythiol to produce a nucleophile. The nucleophile derived from the trifunctional or higher sulfur-containing polythiol then undergoes a nucleophilic substitution reaction with the halogenated hydrocarbon. Examples of basic compounds include metal alcoholates and amine compounds. In such a reaction, the blending ratio of the trifunctional or higher sulfur-containing polythiol and the first modifier is adjusted based on the equivalent ratio of halogen atoms in the first modifier (halogenated hydrocarbon) to mercapto groups in the sulfur-containing polythiol.

[0159] The equivalent ratio of halogen atoms in the first modifying agent (halogenated hydrocarbon) to mercapto groups in the sulfur-containing polythiol (halogen atoms / mercapto groups) is, for example, 0.1 or more, preferably 0.3 or more. The equivalent ratio of halogen atoms in the first modifying agent (halogenated hydrocarbon) to mercapto groups in the sulfur-containing polythiol (halogen atoms / mercapto groups) is, for example, 0.9 or less, preferably 0.8 or less.

[0160] When the first modifying agent contains a halogenated hydrocarbon, the reaction conditions for the nucleophilic substitution reaction are appropriately selected depending on the type of tri- or higher functional sulfur-containing polythiol and the type of the first modifying agent. For example, the reaction temperature is, for example, -20°C or higher, preferably -10°C or higher. The reaction temperature is, for example, 50°C or lower, preferably 30°C or lower. The reaction time is, for example, 3 hours or higher, preferably 6 hours or higher. The reaction time is, for example, 48 hours or lower, preferably 24 hours or lower. The tri- or higher functional sulfur-containing polythiol and the first modifying agent may react in the absence of a solvent or in the presence of a known solvent. The type and amount of the solvent are appropriately determined. The tri- or higher functional sulfur-containing polythiol and the first modifying agent may react in the absence of a catalyst or in the presence of a known catalyst. The type and amount of the catalyst are appropriately determined.

[0161] Furthermore, for example, when the first modifier contains an acyl halide, the trifunctional or higher sulfur-containing polythiol and the first modifier undergo a nucleophilic acylation reaction in the presence of the basic compound described above to produce the compound represented by formula (1). More specifically, the basic compound eliminates protons from the trifunctional or higher sulfur-containing polythiol to produce a nucleophile. The nucleophile derived from the trifunctional or higher sulfur-containing polythiol then undergoes a nucleophilic acylation reaction with the acyl halide. In such a reaction, the blending ratio of the trifunctional or higher sulfur-containing polythiol and the first modifier is adjusted based on the equivalent ratio of halogen atoms in the first modifier (acyl halide) to mercapto groups in the sulfur-containing polythiol.

[0162] The equivalent ratio of halogen atoms in the first modifying agent (acyl halide) to mercapto groups in the sulfur-containing polythiol (halogen atoms / mercapto groups) is, for example, 0.1 or more, preferably 0.3 or more. The equivalent ratio of halogen atoms in the first modifying agent (acyl halide) to mercapto groups in the sulfur-containing polythiol (halogen atoms / mercapto groups) is, for example, 0.9 or less, preferably 0.8 or less.

[0163] When the first modifying agent contains an acyl halide, the reaction conditions for the nucleophilic acylation reaction are appropriately selected depending on the type of trifunctional or higher sulfur-containing polythiol and the type of first modifying agent. For example, the reaction temperature is, for example, -20°C or higher, preferably -10°C or higher. The reaction temperature is, for example, 50°C or lower, preferably 30°C or lower. The reaction time is, for example, 3 hours or longer, preferably 6 hours or longer. The reaction time is, for example, 48 hours or shorter, preferably 24 hours or shorter. The trifunctional or higher sulfur-containing polythiol and the first modifying agent may react without a solvent or in the presence of a known solvent. The type and amount of the solvent are appropriately determined. The trifunctional or higher sulfur-containing polythiol and the first modifying agent may react without a catalyst or in the presence of a known catalyst. The type and amount of the catalyst are appropriately determined.

[0164] Furthermore, for example, when the first modifier contains a carboxylic acid, the trifunctional or higher sulfur-containing polythiol and the first modifier (carboxylic acid) undergo a dehydration condensation reaction in the presence of the basic compound to produce the compound represented by formula (1). In such a reaction, the blending ratio of the trifunctional or higher sulfur-containing polythiol and the first modifier is adjusted based on the equivalent ratio of carboxy groups in the first modifier (carboxylic acid) to mercapto groups in the sulfur-containing polythiol. The equivalent ratio of carboxy groups in the first modifier (carboxylic acid) to mercapto groups in the sulfur-containing polythiol (carboxy group / mercapto group) is, for example, 0.1 or more, preferably 0.5 or more. The equivalent ratio of carboxy groups in the first modifier (carboxylic acid) to mercapto groups in the sulfur-containing polythiol (carboxy group / mercapto group) is, for example, 0.9 or less, preferably 0.8 or less.

[0165] When the first modifying agent contains a carboxylic acid, the reaction conditions for the dehydration condensation reaction are appropriately selected depending on the type of trifunctional or higher sulfur-containing polythiol and the type of first modifying agent. For example, the reaction temperature is, for example, -20°C or higher, preferably -10°C or higher. The reaction temperature is, for example, 50°C or lower, preferably 30°C or lower. The reaction time is, for example, 3 hours or longer, preferably 6 hours or longer. The reaction time is, for example, 48 hours or shorter, preferably 24 hours or shorter. The trifunctional or higher sulfur-containing polythiol and the first modifying agent may react without a solvent or may react with a known solvent. The type and amount of the solvent are appropriately determined. The trifunctional or higher sulfur-containing polythiol and the first modifying agent may react without a catalyst or may react with a known catalyst. The type and amount of the catalyst are appropriately determined.

[0166] As described above, in the first reaction step, at least a portion of the mercapto groups (SH groups) of the polythiol are modified by the first modifying agent to form SXR' groups. Furthermore, the remaining mercapto groups (SH groups) of the polythiol (hereinafter referred to as "residual mercapto groups") remain without being modified. This results in a primary reaction product. The primary reaction product is the reaction product of the first reaction step.

[0167] In this method, after the first reaction step, the reaction product (primary reaction product) from the first reaction step is reacted with the second modifying agent by an appropriate method (second reaction step).

[0168] The formulation, reaction method and reaction conditions in the second reaction step are appropriately selected depending on, for example, the type of the second modifying agent.

[0169] For example, when the second modifying agent contains a (meth)acrylic acid halide, the residual mercapto groups in the primary reaction product undergo a condensation reaction with the halogen atoms in the (meth)acrylic acid halide, thereby forming thio(meth)acryloyl groups. In this reaction, the blending ratio of the second modifying agent is adjusted based on the equivalent ratio of the halogen atoms in the second modifying agent ((meth)acrylic acid halide) to the residual mercapto groups in the primary reaction product.

[0170] The equivalent ratio of halogen atoms in the second modifying agent ((meth)acrylic acid halide) to the residual mercapto groups in the primary reaction product (halogen atoms / residual mercapto groups) is, for example, 0.8 or more, preferably 0.9 or more. The equivalent ratio of halogen atoms in the second modifying agent ((meth)acrylic acid halide) to the residual mercapto groups in the primary reaction product (halogen atoms / residual mercapto groups) is, for example, 1.5 or less, preferably 1.3 or less.

[0171] When the second modifying agent contains a (meth)acrylic acid halide, the reaction conditions are appropriately selected depending on the type of trifunctional or higher sulfur-containing polythiol, the type of first modifying agent, and the type of second modifying agent. The primary reaction product and the second modifying agent may react in the absence of a solvent or in the presence of a known solvent. The type and amount of the solvent are appropriately determined. The primary reaction product and the second modifying agent may react in the absence of a catalyst or in the presence of a known catalyst. The type and amount of the catalyst are appropriately determined.

[0172] For example, when the second modifier contains (meth)acrylic anhydride, the residual mercapto groups of the primary reaction product undergo a condensation reaction with the (meth)acrylic anhydride by a known method, thereby forming thio(meth)acryloyl groups. In this reaction, the blending ratio of the second modifier ((meth)acrylic anhydride) is adjusted based on the equivalent ratio of the residual mercapto groups of the primary reaction product.

[0173] The equivalent ratio ((meth)acrylic anhydride) of the second modifying agent to the residual mercapto groups of the primary reaction product ((meth)acrylic anhydride / residual mercapto groups) is, for example, 0.8 or more, preferably 0.9 or more. The equivalent ratio ((meth)acrylic anhydride / residual mercapto groups) of the second modifying agent to the residual mercapto groups of the primary reaction product is, for example, 1.5 or less, preferably 1.3 or less.

[0174] When the second modifier contains (meth)acrylic anhydride, the reaction conditions are appropriately selected depending on the type of trifunctional or higher sulfur-containing polythiol, the type of first modifier, and the type of second modifier. The primary reaction product and the second modifier may react in the absence of a solvent or in the presence of a known solvent. The type and amount of the solvent are appropriately determined. The primary reaction product and the second modifier may react in the absence of a catalyst or in the presence of a known catalyst. The type and amount of the catalyst are appropriately determined.

[0175] For example, when the second modifying agent contains (meth)acrylic anhydride, the residual mercapto groups of the primary reaction product undergo a condensation reaction with the (meth)acrylic anhydride by a known method. In such a reaction, the blending ratio of the second modifying agent ((meth)acrylic anhydride) is adjusted based on the equivalent ratio of the residual mercapto groups of the primary reaction product.

[0176] The equivalent ratio ((meth)acrylic anhydride) of the second modifying agent to the residual mercapto groups of the primary reaction product ((meth)acrylic anhydride / residual mercapto groups) is, for example, 0.8 or more, preferably 0.9 or more. The equivalent ratio ((meth)acrylic anhydride / residual mercapto groups) of the second modifying agent to the residual mercapto groups of the primary reaction product is, for example, 1.5 or less, preferably 1.3 or less.

[0177] When the second modifier contains (meth)acrylic anhydride, the reaction conditions are appropriately selected depending on the type of trifunctional or higher sulfur-containing polythiol, the type of first modifier, and the type of second modifier. The primary reaction product and the second modifier may react in the absence of a solvent or in the presence of a known solvent. The type and amount of the solvent are appropriately determined. The primary reaction product and the second modifier may react in the absence of a catalyst or in the presence of a known catalyst. The type and amount of the catalyst are appropriately determined.

[0178] When the second modifying agent contains (meth)acrylic acid and a dehydration condensing agent, the residual mercapto groups of the primary reaction product undergo a condensation reaction with the (meth)acrylic acid in the presence of the dehydration condensing agent, thereby forming thio(meth)acryloyl groups. In this reaction, the blending ratio of the second modifying agent is adjusted based on the equivalent ratio of the (meth)acrylic acid in the second modifying agent to the residual mercapto groups of the primary reaction product.

[0179] The equivalent ratio of (meth)acrylic acid in the second modifying agent to the residual mercapto groups in the primary reaction product ((meth)acrylic acid / residual mercapto groups) is, for example, 0.8 or more, preferably 0.9 or more. The equivalent ratio of (meth)acrylic acid in the second modifying agent to the residual mercapto groups in the primary reaction product ((meth)acrylic acid / residual mercapto groups) is, for example, 1.5 or less, preferably 1.3 or less.

[0180] When the second modifying agent contains (meth)acrylic acid and a dehydration condensation agent, the reaction conditions are appropriately selected depending on the type of trifunctional or higher sulfur-containing polythiol, the type of first modifying agent, and the type of second modifying agent. The primary reaction product and the second modifying agent may react in the absence of a solvent or in the presence of a known solvent. The type and amount of the solvent are appropriately determined. The primary reaction product and the second modifying agent may react in the absence of a catalyst or in the presence of a known catalyst. The type and amount of the catalyst are appropriately determined.

[0181] Furthermore, when the second modifying agent contains a propionic acid derivative and a basic compound, the remaining mercapto groups of the primary reaction product react with the propionic acid derivative and the basic compound according to the method described in Japanese Patent Application Laid-Open No. 4-29967. More specifically, first, the remaining mercapto groups of the primary reaction product undergo a condensation reaction with the propionic acid derivative. Next, the halogens of these reaction products (condensates) are treated (eliminated) with a basic compound to form ethylenically unsaturated bonds. This results in the formation of thio(meth)acryloyl groups. In this reaction, the blending ratio of the second modifying agent is adjusted based on the equivalent ratio of the propionic acid derivative in the second modifying agent to the remaining mercapto groups of the primary reaction product.

[0182] The equivalent ratio of the propionic acid derivative in the second modifying agent to the residual mercapto groups in the primary reaction product (propionic acid derivative / residual mercapto groups) is, for example, 0.8 or more, preferably 0.9 or more. The equivalent ratio of the propionic acid derivative in the second modifying agent to the residual mercapto groups in the primary reaction product (propionic acid derivative / residual mercapto groups) is, for example, 1.5 or less, preferably 1.3 or less.

[0183] When the second modifier contains a propionic acid derivative and a basic compound, the reaction conditions are appropriately selected depending on the type of trifunctional or higher sulfur-containing polythiol, the type of first modifier, and the type of second modifier. The primary reaction product and the second modifier may react without a solvent or in the presence of a known solvent. The type and amount of the solvent are appropriately determined. The primary reaction product and the second modifier may react without a catalyst or in the presence of a known catalyst. The type and amount of the catalyst are appropriately determined.

[0184] As described above, in the second reaction step, the remaining mercapto groups of the primary reaction product are modified to form thio(meth)acryloyl groups. This results in a secondary reaction product. The secondary reaction product is the reaction product of the second reaction step.

[0185] That is, in the above method, a portion of the mercapto groups of the trifunctional or higher sulfur-containing polythiol is modified with a first modifying agent. As a result, an SXR' group is bonded to the residue (organic group A) of the trifunctional or higher sulfur-containing polythiol. Also, in the above method, the remainder of a portion of the mercapto groups of the trifunctional or higher sulfur-containing polythiol is modified with a second modifying agent. As a result, a thio(meth)acryloyl group is bonded to the residue (organic group A) of the trifunctional or higher sulfur-containing polythiol. As a result, the above additive composition is produced as a reaction product by the above method.

[0186] The method for obtaining the additive composition is not limited to the above. For example, an ene-thiol reaction can be used as a reaction between a trifunctional or higher sulfur-containing polythiol and a first modifier. Examples of the first modifier include compounds capable of undergoing an ene-thiol reaction with the trifunctional or higher sulfur-containing polythiol. Examples of such compounds include vinyl compounds. Examples of vinyl compounds include styrene, methylstyrene, and butylstyrene. These compounds can be used alone or in combination. When a vinyl compound is used as the first modifier, the trifunctional or higher sulfur-containing polythiol and the first modifier (vinyl compound) undergo an ene-thiol reaction in the presence of a known radical initiator, modifying the mercapto group of the trifunctional or higher sulfur-containing polythiol to an SXR′ group (X represents a single bond, and R′ represents a hydrocarbon group derived from a vinyl compound). The primary reaction product can also be obtained by this method. The primary reaction product is then reacted with the second modifier to obtain the additive composition.

[0187] The reaction product of the trifunctional or higher sulfur-containing polythiol, the first modifier, and the second modifier contains the compound represented by the formula (1), the compound represented by the formula (2), and the compound represented by the formula (3). Therefore, the reaction product is used as an additive composition. If necessary, the reaction product can be purified by an appropriate method, and the purified product can be used as an additive composition.

[0188] In the additive composition, the content ratios of the compound represented by the formula (1), the compound represented by the formula (2), and the compound represented by the formula (3) are measured in accordance with the Examples described later. More specifically, the molar ratios of the compound represented by the formula (1), the compound represented by the formula (2), and the compound represented by the formula (3) can be calculated from the peak area ratio (LC%) obtained by high performance liquid chromatography (HPLC). Furthermore, the mass ratio can be calculated from the molar ratio based on the molecular weight of each compound.

[0189] The amount of the compound represented by the formula (1), the amount of the compound represented by the formula (2), and the amount of the compound represented by the formula (3) will be described in detail later.

[0190] [v] Other additives The additive may contain other additives. The other additives are additives other than the compound represented by the above formula (1), the compound represented by the above formula (2), and the compound represented by the above formula (3).

[0191] Examples of other additives include the above-mentioned radical polymerization initiators, silane coupling agents (e.g., (meth)acrylic group-containing silane coupling agents), other crosslinking agents (crosslinking agents other than the compounds represented by the above formulas (1) and (2)), plasticizers (other than the compounds represented by the above formula (3)), antioxidants, ultraviolet absorbers, antistatic agents, coatability improvers, leveling agents, antifoaming agents, plasticizers, surfactants, pigments, fillers, antifungal agents, processing aids, and antioxidants. These can be used alone or in combination of two or more. Preferred examples of other additives include radical polymerization initiators and silane coupling agents. The amount of other additives added is appropriately determined depending on the purpose and application.

[0192] 3)Content ratio The curable composition contains the (meth)acrylic resin and the additives described above, and is prepared by mixing the (meth)acrylic resin and the additives described above by a known method.

[0193] <(Meth)acrylic resin content> From the viewpoints of suppressing cloudiness and adhesiveness, the content of the (meth)acrylic resin is, for example, 70.0 mass% or more, preferably 80.0 mass% or more, more preferably 80.0 mass% or more, even more preferably 90.0 mass% or more, and particularly preferably 95.0 mass% or more, based on the total amount (solid content) of the curable composition. Also, from the viewpoints of suppressing cloudiness and adhesiveness, the content of the (meth)acrylic resin is, for example, 99.9 mass% or less, preferably 99.5 mass% or less, more preferably 99.0 mass% or less, even more preferably 98.5 mass% or less, and particularly preferably 98.0 mass% or less, based on the total amount (solid content) of the curable composition. That is, from the viewpoints of suppressing cloudiness and adhesiveness, the content of the (meth)acrylic resin relative to the total amount (based on the solid content) of the curable composition is, for example, 70.0 mass % or more and 99.9 mass % or less, preferably 80.0 mass % or more and 99.5 mass % or less, more preferably 80.0 mass % or more and 99.0 mass % or less, even more preferably 90.0 mass % or more and 98.5 mass % or less, and particularly preferably 95.0 mass % or more and 98.0 mass % or less.

[0194] <Content of the compound represented by the above formula (1)> From the viewpoint of suppressing cloudiness and adhesiveness, the content of the compound represented by the above formula (1) is, for example, 0.1 mass% or more, preferably 0.2 mass% or more, more preferably 0.3 mass% or more, even more preferably 0.4 mass% or more, and particularly preferably 0.5 mass% or more, based on the total amount (solid content) of the curable composition. Also, from the viewpoint of suppressing cloudiness and adhesiveness, the content of the compound represented by the above formula (1) is, for example, 4.0 mass% or less, preferably 3.0 mass% or less, more preferably 2.5 mass% or less, even more preferably 2.0 mass% or less, and particularly preferably 1.5 mass% or less, based on the total amount (solid content) of the curable composition. That is, from the viewpoints of suppressing cloudiness and adhesiveness, the content of the compound represented by the above formula (1) is, for example, 0.1 mass % or more and 4.0 mass % or less, preferably 0.2 mass % or more and 3.0 mass % or less, more preferably 0.3 mass % or more and 2.5 mass % or less, even more preferably 0.4 mass % or more and 2.0 mass % or less, and particularly preferably 0.5 mass % or more and 1.5 mass % or less, relative to the total amount (based on the solid content) of the curable composition.

[0195] Furthermore, from the viewpoint of suppressing cloudiness and adhesion, the content of the compound represented by the above formula (1) is, for example, 1% by mass or more and 80% by mass or less, preferably 5% by mass or more and 70% by mass or less, more preferably 10% by mass or more and 60% by mass or less, even more preferably 20% by mass or more and 50% by mass or less, and particularly preferably 30% by mass or more and 40% by mass or less, relative to the total amount of the compound represented by the above formula (1), the compound represented by the above formula (2), and the compound represented by the above formula (3).

[0196] From the viewpoints of refractive index, suppression of clouding, and adhesiveness, the content of the compound represented by the above formula (1) is, for example, 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and particularly preferably 0.8 parts by mass or more, relative to 100 parts by mass (based on solids) of the (meth)acrylic resin. From the viewpoints of refractive index, suppression of clouding, and adhesiveness, the content of the compound represented by the above formula (1) is, for example, 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and particularly preferably 0.8 parts by mass or more, relative to 100 parts by mass (based on solids) of the (meth)acrylic resin. That is, from the viewpoints of refractive index, suppression of cloudiness, and adhesiveness, the content of the compound represented by the above formula (1) is, for example, 0.01 parts by mass or more and less than 5.0 parts by mass, preferably 0.1 parts by mass or more and 4.5 parts by mass or less, more preferably 0.3 parts by mass or more and 3.0 parts by mass or less, even more preferably 0.5 parts by mass or more and 2.0 parts by mass or less, and particularly preferably 0.8 parts by mass or more and 1.5 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic resin (based on the solid content).

[0197] <Content of the compound represented by the above formula (2)> From the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (2) is, for example, 0 mass% or more, preferably 0.5 mass% or more, more preferably 1.0 mass% or more, even more preferably 1.5 mass% or more, and particularly preferably 2.0 mass% or more, based on the total amount (solid content) of the curable composition. Also, from the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (2) is, for example, 10.0 mass% or less, preferably 8.0 mass% or less, more preferably 7.0 mass% or less, even more preferably 6.0 mass% or less, and particularly preferably 5.0 mass% or less, based on the total amount (solid content) of the curable composition. That is, from the viewpoints of suppressing cloudiness and adhesiveness, the content (total amount) of the compound represented by the above formula (2) is, for example, 0 mass % or more and 10.0 mass % or less, preferably 0.5 mass % or more and 8.0 mass % or less, more preferably 1.0 mass % or more and 7.0 mass % or less, even more preferably 1.5 mass % or more and 6.0 mass % or less, and particularly preferably 2.0 mass % or more and 5.0 mass % or less, relative to the total amount (based on the solid content) of the curable composition.

[0198] Furthermore, from the viewpoint of suppressing cloudiness and adhesion, the content of the compound represented by the above formula (2) is, for example, 10% by mass or more and 95% by mass or less, preferably 20% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 85% by mass or less, even more preferably 40% by mass or more and 80% by mass or less, and particularly preferably 50% by mass or more and 70% by mass or less, relative to the total amount of the compound represented by the above formula (1), the compound represented by the above formula (2), and the compound represented by the above formula (3).

[0199] In addition, from the viewpoint of suppressing cloudiness and adhesiveness, the content (total amount) of the compound represented by the above formula (2) is, for example, 0 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, even more preferably 1.5 parts by mass or more, and particularly preferably 2.0 parts by mass or more, relative to 100 parts by mass (solid content) of the (meth)acrylic resin. In addition, from the viewpoint of suppressing cloudiness and adhesiveness, the content (total amount) of the compound represented by the above formula (2) is, for example, 10.0 parts by mass or less, preferably 8.0 parts by mass or less, more preferably 7.0 parts by mass or less, even more preferably 6.0 parts by mass or less, and particularly preferably 4.0 parts by mass or less, relative to 100 parts by mass (solid content) of the (meth)acrylic resin. That is, from the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (2) is, for example, 0 parts by mass or more and 10.0 parts by mass or less, preferably 0.5 parts by mass or more and 8.0 parts by mass or less, more preferably 1.0 parts by mass or more and 7.0 parts by mass or less, even more preferably 1.5 parts by mass or more and 6.0 parts by mass or less, and particularly preferably 2.0 parts by mass or more and 4.0 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic resin (based on the solid content).

[0200] Furthermore, the compound represented by the above formula (2) preferably contains a compound represented by the above formula (2) and having two or more thio(meth)acryloyl groups (i.e., m is an integer of 2 or more).

[0201] From the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (2) and having two or more thio(meth)acryloyl groups is, relative to the total amount (solid content) of the curable composition, for example, 0% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, even more preferably 1.5% by mass or more, and particularly preferably 1.8% by mass or more. Also, from the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (2) and having two or more thio(meth)acryloyl groups is, relative to the total amount (solid content) of the curable composition, for example, 10.0% by mass or less, preferably 8.0% by mass or less, more preferably 7.0% by mass or less, even more preferably 6.0% by mass or less, and particularly preferably 3.0% by mass or less. That is, from the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (2) and having two or more thio(meth)acryloyl groups is, for example, 0 mass% or more and 10.0 mass% or less, preferably 0.5 mass% or more and 8.0 mass% or less, more preferably 1.0 mass% or more and 7.0 mass% or less, even more preferably 1.5 mass% or more and 5.0 mass% or less, and particularly preferably 1.8 mass% or more and 3.0 mass% or less, relative to the total amount (based on the solid content) of the curable composition.

[0202] The content of the compound represented by the above formula (2) and having two or more thio(meth)acryloyl groups is, for example, 10% by mass or more and 90% by mass or less, preferably 15% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, even more preferably 25% by mass or more and 60% by mass or less, and particularly preferably 30% by mass or more and 50% by mass or less, relative to the total amount of the compound represented by the above formula (1), the compound represented by the above formula (2), and the compound represented by the above formula (3).

[0203] In addition, from the viewpoint of suppressing cloudiness and adhesiveness, the content (total amount) of the compound represented by the above formula (2) and having two or more thio(meth)acryloyl groups is, for example, 0 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 0.8 parts by mass or more, and particularly preferably 1.0 parts by mass or more, relative to 100 parts by mass (solid content) of the (meth)acrylic resin. In addition, from the viewpoint of suppressing cloudiness and adhesiveness, the content (total amount) of the compound represented by the above formula (2) and having two or more thio(meth)acryloyl groups is, for example, 9.0 parts by mass or less, preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass or less, even more preferably 5.0 parts by mass or less, and particularly preferably 3.0 parts by mass or less, relative to 100 parts by mass (solid content) of the (meth)acrylic resin. That is, from the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (2) and having two or more thio(meth)acryloyl groups is, for example, 0 parts by mass or more and 9.0 parts by mass or less, preferably 0.5 parts by mass or more and 8.0 parts by mass or less, more preferably 0.5 parts by mass or more and 6.0 parts by mass or less, even more preferably 0.8 parts by mass or more and 5.0 parts by mass or less, and particularly preferably 1.0 parts by mass or more and 3.0 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic resin (based on the solid content).

[0204] <Content of the compound represented by the above formula (3)> From the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (3) is, for example, 0 mass% or more, preferably 0.01 mass% or more, more preferably 0.05 mass% or more, even more preferably 0.1 mass% or more, and particularly preferably 0.2 mass% or more, based on the total amount (solid content) of the curable composition. Also, from the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (3) is, for example, 10.0 mass% or less, preferably 5.0 mass% or less, more preferably 3.0 mass% or less, even more preferably 1.0 mass% or less, and particularly preferably 0.5 mass% or less, based on the total amount (solid content) of the curable composition. That is, from the viewpoints of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (3) is, for example, 0 mass % or more and 10.0 mass % or less, preferably 0.01 mass % or more and 5.0 mass % or less, more preferably 0.05 mass % or more and 3.0 mass % or less, even more preferably 0.1 mass % or more and 1.0 mass % or less, and particularly preferably 0.2 mass % or more and 0.5 mass % or less, relative to the total amount (based on the solid content) of the curable composition.

[0205] Furthermore, from the viewpoint of suppressing cloudiness and adhesion, the content of the compound represented by the above formula (3) is, for example, 0.1% by mass or more and 30% by mass or less, preferably 0.5% by mass or more and 25% by mass or less, more preferably 1% by mass or more and 20% by mass or less, even more preferably 2% by mass or more and 15% by mass or less, and particularly preferably 3% by mass or more and 10% by mass or less, relative to the total amount of the compound represented by the above formula (1), the compound represented by the above formula (2), and the compound represented by the above formula (3).

[0206] In addition, from the viewpoint of suppressing cloudiness and adhesiveness, the content (total amount) of the compound represented by the above formula (3) is, for example, 0 part by mass or more, preferably 0.01 part by mass or more, more preferably 0.05 part by mass or more, even more preferably 0.1 part by mass or more, and particularly preferably 0.2 part by mass or more, relative to 100 parts by mass (based on solid content) of the (meth)acrylic resin. In addition, from the viewpoint of suppressing cloudiness and adhesiveness, the content (total amount) of the compound represented by the above formula (3) is, for example, 10.0 parts by mass or less, preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass or less, even more preferably 4.0 parts by mass or less, and particularly preferably 3.0 parts by mass or less, relative to 100 parts by mass (based on solid content) of the (meth)acrylic resin. That is, from the viewpoint of suppressing cloudiness and adhesion, the content (total amount) of the compound represented by the above formula (3) is, for example, 0 parts by mass or more and 10.0 parts by mass or less, preferably 0.01 parts by mass or more and 8.0 parts by mass or less, more preferably 0.05 parts by mass or more and 6.0 parts by mass or less, even more preferably 0.1 parts by mass or more and 4.0 parts by mass or less, and particularly preferably 0.2 parts by mass or more and 3.0 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic resin (based on the solid content).

[0207] 4) Action and effect The curable composition contains the compound represented by the formula (1) in a predetermined ratio, and therefore, the curable composition can prevent the pressure-sensitive adhesive from becoming cloudy.

[0208] 2. Adhesive 1) Overall structure The pressure-sensitive adhesive contains a cured product of the above-mentioned curable composition, and preferably consists of a cured product of the above-mentioned curable composition.

[0209] The adhesive is a cured resin having adhesive properties (pressure-sensitive adhesiveness, tackiness). More specifically, the adhesive has a relatively low glass transition temperature.

[0210] The glass transition temperature of the pressure-sensitive adhesive is, for example, 20°C or lower, preferably 0°C or lower, more preferably -3°C or lower, and even more preferably -10°C or lower. The glass transition temperature of the pressure-sensitive adhesive is not particularly limited, but is, for example, -50°C or higher. That is, the glass transition temperature of the pressure-sensitive adhesive is, for example, -50°C or higher and 20°C or lower, preferably -50°C or higher and 0°C or lower, more preferably -50°C or higher and -3°C or lower, and even more preferably -50°C or higher and -10°C or lower. The glass transition temperature is measured in accordance with the examples described below.

[0211] 2) Manufacturing method The method for producing the pressure-sensitive adhesive is not particularly limited. For example, the pressure-sensitive adhesive can be obtained as a cured product by curing the curable composition.

[0212] The method for curing the curable composition is not particularly limited. For example, the curable composition may be irradiated with active energy rays and / or heated in the presence of a radical polymerization initiator.

[0213] Examples of active energy rays include ultraviolet rays and electron beams. The wavelength of the active energy rays is appropriately set depending on the purpose and application. The integrated light amount is, for example, 0.1 mJ / cm. 2 The cumulative light amount is, for example, 5000 mJ / cm 2 Preferably, 3000 mJ / cm or less 2 The illuminance is, for example, 0.01 mW / cm 2 The illuminance is, for example, 500 mW / cm 2 Preferably, 300 mW / cm or less 2 The following is the result.

[0214] Heating conditions are appropriately set depending on the purpose and application. The heating temperature is, for example, 40°C or higher, preferably 50°C or higher. The heating temperature is, for example, 200°C or lower, preferably 100°C or lower. The heating time is, for example, 1 minute or longer, preferably 5 minutes or longer. The heating time is, for example, 10 hours or shorter, preferably 5 hours or shorter.

[0215] By irradiating the curable composition with active energy rays and / or heating the curable composition, the compound represented by formula (1) acts as a crosslinking agent, crosslinking and curing the (meth)acrylic resin. Furthermore, when the curable composition contains a compound represented by formula (2) where m is 2 or more, such a compound also acts as a crosslinking agent, crosslinking and curing the (meth)acrylic resin.

[0216] As a result, a cured product of the curable composition is obtained. The cured product of the curable composition has adhesiveness due to the (meth)acrylic resin. In other words, the cured product of the curable composition is an adhesive.

[0217] 3) Physical properties The refractive index of the pressure-sensitive adhesive is, for example, 1.45 or more, preferably 1.50 or more, more preferably 1.55 or more, even more preferably 1.58 or more, and particularly preferably 1.59 or more. The refractive index of the pressure-sensitive adhesive is, for example, 1.80 or less, preferably 1.70 or less. The refractive index is measured in accordance with the examples described below.

[0218] The pressure-sensitive adhesive has a shear storage modulus (G') at 25°C of, for example, 1 kPa or more, preferably 10 kPa or more, more preferably 20 kPa or more, and even more preferably 30 kPa or more. The upper limit of the pressure-sensitive adhesive's shear storage modulus (G') at 25°C is not particularly limited, but is, for example, 100 kPa or less. The shear storage modulus (G') at 25°C is measured in accordance with the examples described below.

[0219] 4) Action and effect The pressure-sensitive adhesive contains the cured product of the curable composition, and therefore can suppress cloudiness.

[0220] The pressure-sensitive adhesive described above is suitable for use in various industrial fields as a pressure-sensitive adhesive capable of adhering to various adherends, including, but not limited to, paper, cloth, leather, resin sheets, rubber sheets, foams, metals, glass, and wood.

[0221] The pressure-sensitive adhesive also contains sulfur atoms. Therefore, the pressure-sensitive adhesive has excellent adhesion to metals. As a result, the pressure-sensitive adhesive is suitable for use in fields where the adherend is a metal. Examples of such fields include the fields of building materials, electronic components, semiconductors, component sealing, automotive components, aviation components, and sporting goods.

[0222] Examples of building materials include barrier materials, roofing materials, solar panel materials, battery packaging materials, window materials, outdoor flooring materials, lighting protection materials, automotive parts, signs, and stickers. Examples of electronic components include electronic materials and laminates for electrical and electronic circuits, more specifically, flexible copper-clad laminates, coverlays, bonding sheets, resin-coated copper foils, multilayer printed wiring boards, capacitors, underfill materials, interchip fills for 3D-LSIs, insulating sheets, heat dissipation substrates, and metal foil adhesives for heat dissipation films.

[0223] Furthermore, the pressure-sensitive adhesive can suppress cloudiness and has excellent refractive index and flexibility. Therefore, the pressure-sensitive adhesive is preferably used in the optical field. That is, the pressure-sensitive adhesive is preferably an optical pressure-sensitive adhesive.

[0224] More specifically, in recent years, bendable and / or flexible displays have been put to practical use as displays for organic electroluminescence (EL) display devices. Examples of such displays include foldable displays and rollable displays. Bendable and / or flexible displays require optical pressure-sensitive adhesives that can follow the bending and / or curvature. More specifically, pressure-sensitive adhesives that combine a relatively high refractive index and relatively high flexibility are required. However, from the perspective of refractive index, relatively high crystallinity is required, and from the perspective of flexibility, relatively low crystallinity is required. Therefore, there is a trade-off between refractive index and flexibility, and it is difficult to combine a relatively high refractive index and relatively high flexibility.

[0225] In contrast, the pressure-sensitive adhesive described above can suppress cloudiness and has excellent refractive index and flexibility, and is therefore particularly suitable for use as an optical pressure-sensitive adhesive that can conform to bending and / or curvature. [Example]

[0226] Specific numerical values ​​of blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the corresponding upper limit values ​​(numeric values ​​defined as "not more than" or "less than") or lower limit values ​​(numeric values ​​defined as "not less than" or "exceeding") of blending ratios (content ratios), physical property values, parameters, etc. described in the above "Description of the Invention." Furthermore, unless otherwise specified in the following description, "parts" and "%" are based on mass.

[0227] 1. Additive Preparation Preparation example 1 The following compound (GSTA) was prepared as an additive.

[0228] That is, GSTA (1,8-bisacryloylthio-(4-acryloylthiomethyl-3,6-dithiaoctane)) was synthesized in accordance with Example 3 of JP-A-4-29967.

[0229] Preparation example 2 (Ac1.0-GSTA) As an additive composition, the following secondary reaction product (Ac1.0-GSTA) was prepared.

[0230] (1) First reaction step A four-neck flask equipped with a stirrer, a thermometer, a nitrogen inlet line, and a dropping funnel was charged with 20.0 g (76.8 mmol) of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (trifunctional sulfur-containing polythiol (GST)). 100 mL of toluene was then added to the flask to dissolve the GST in toluene.

[0231] The flask was then slowly charged with 23.3 g of triethylamine (base catalyst, 230.3 mmol) with stirring.

[0232] The solution in the flask was then cooled in an ice bath, and 7.8 g of acetic anhydride (first modifying agent, 76.8 mmol) was added dropwise to the flask while maintaining the temperature in the flask at 10° C. or lower.

[0233] After the dropwise addition was completed, the ice bath was removed and the temperature in the flask was returned to room temperature. The reaction mixture in the flask was stirred overnight, thereby forming acetyl groups derived from acetic anhydride.

[0234] Then, 300 mL of water and 200 mL of toluene were added to the reaction product solution in the flask. The organic phase was then separated by a separation operation. The organic phase was then washed with dilute hydrochloric acid. The organic phase was then washed with a saturated aqueous solution of sodium bicarbonate. The solvent in the organic phase was then removed using an evaporator. This yielded a crude product.

[0235] The crude product was diluted with 100 mL of toluene to obtain a diluted solution. The diluted solution was passed through 20 mL of silica gel. The diluted solution was then eluted using 300 mL of toluene. The eluted diluted solution was then concentrated using an evaporator. This yielded 24.1 g of a primary reaction product. The primary reaction product was a partially acetylated GST.

[0236] In the above reaction, 1 / 3 equivalent of the mercapto groups (trifunctional) of GST were acetylated.

[0237] (2) Second reaction step A four-neck flask equipped with a stirrer, a thermometer, a nitrogen inlet line, and a dropping funnel was charged with 20.0 g of the primary reaction product described above. Next, 100 mL of dichloromethane was added to the flask to dilute the primary reaction product with dichloromethane.

[0238] The diluted solution in the flask was then cooled in an ice bath, and 25.2 g of 3-chloropropionyl chloride (second modifier, 198.3 mmol) was added dropwise to the flask while maintaining the temperature in the flask at 40° C. or lower.

[0239] The reaction mixture in the flask was then stirred at room temperature for 48 hours. Then, purified water (100 mL) was added to the flask. The organic phase was then separated by a separation operation. The organic phase was then washed twice with saturated aqueous sodium bicarbonate (100 mL). The solvent in the organic phase was then removed using an evaporator.

[0240] The reaction product was then placed in a four-neck flask equipped with a thermometer and a dropping funnel. 23 mg of 4-methoxyphenol (a polymerization inhibitor) was also added to the flask. The contents of the flask were then stirred at room temperature to dissolve the 4-methoxyphenol.

[0241] The diluted solution in the flask was then cooled in an ice bath. Then, while maintaining the temperature in the flask at 40°C or below, 17.4 g (171.9 mmol) of triethylamine (second modifier, base) was added dropwise to the flask. The reaction product in the flask was then stirred at room temperature for 1 hour. This treated the reaction product with a base, resulting in the formation of acryloyl groups derived from 3-chloropropionyl chloride.

[0242] Then, 1M hydrochloric acid (300 mL) was added to the reaction product solution in the flask, and the organic phase was separated by a separation operation.

[0243] The organic phase was then passed through silica gel (30 mL), and 23 mg of 4-methoxyphenol (polymerization inhibitor) was added to the organic phase, followed by concentration under reduced pressure.

[0244] As a result, 26.1 g of a colorless and transparent secondary reaction product (hereinafter referred to as Ac1.0-GSTA) was obtained. The secondary reaction product was an acetylated product and an acrylated product of GST.

[0245] In the above reaction, 2 / 3 equivalents of the mercapto groups (trifunctional) of GST were acrylated.

[0246] The secondary reaction product was analyzed by high performance liquid chromatography (HPLC). The reaction product was a polymerized component containing the following components in the following molar proportions:

[0247] Trithio(meth)acryloyl modified GST 35.8 mol% (LC%, formula (1)) Dithio(meth)acryloyl modified GST 40.8 mol% (LC%, formula (2), m = 2) Monothio(meth)acryloyl modified GST 16.7 mol% (LC%, formula (2), m = 1) Unmodified thio(meth)acryloyl GST 6.7 mol% (LC%, formula (3))

[0248] Based on the molecular weight of each compound, the above molar ratio was converted to a mass ratio as follows. Trithio(meth)acryloyl modified GST 36.8% by mass (formula (1)) Dithio(meth)acryloyl-modified GST 40.7% by mass (formula (2), m = 2) Monothio(meth)acryloyl-modified GST 16.2% by mass (formula (2), m = 1) Unmodified thio(meth)acryloyl GST 6.3% by mass (formula (3))

[0249] Preparation example 3 (Ac2.0-GSTA) As an additive composition, the following secondary reaction product (Ac2.0-GSTA) was prepared.

[0250] (1) First reaction step A four-neck flask equipped with a stirrer, a thermometer, a nitrogen inlet line, and a dropping funnel was charged with 20.0 g (76.8 mmol) of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (trifunctional sulfur-containing polythiol (GST)). 100 mL of toluene was then added to the flask to dissolve the GST in toluene.

[0251] The flask was then slowly charged with 23.3 g of triethylamine (base catalyst, 230.3 mmol) with stirring.

[0252] The solution in the flask was then cooled in an ice bath, and 15.7 g of acetic anhydride (first modifier, 153.5 mmol) was added dropwise to the flask while maintaining the temperature in the flask at 10° C. or lower.

[0253] After the dropwise addition was completed, the ice bath was removed and the temperature in the flask was returned to room temperature. The reaction mixture in the flask was stirred overnight, thereby forming acetyl groups derived from acetic anhydride.

[0254] Then, 300 mL of water and 200 mL of toluene were added to the reaction product solution in the flask. The organic phase was then separated by a separation operation. The organic phase was then washed with dilute hydrochloric acid. The organic phase was then washed with a saturated aqueous solution of sodium bicarbonate. The solvent in the organic phase was then removed using an evaporator. This yielded a crude product.

[0255] The crude product was diluted with 100 mL of toluene to obtain a diluted solution. The diluted solution was passed through 20 mL of silica gel. The diluted solution was then eluted using 300 mL of toluene. The eluted diluted solution was then concentrated using an evaporator. This yielded 26.0 g of a primary reaction product. The primary reaction product was a partially acetylated GST.

[0256] In the above reaction, 2 / 3 equivalents of the mercapto groups (trifunctional) of GST were acetylated.

[0257] (2) Second reaction step A four-neck flask equipped with a stirrer, a thermometer, a nitrogen inlet line, and a dropping funnel was charged with 20.0 g of the primary reaction product described above. Next, 100 mL of dichloromethane was added to the flask to dilute the primary reaction product with dichloromethane.

[0258] The diluted solution in the flask was then cooled in an ice bath, and 14.7 g of 3-chloropropionyl chloride (second modifier, 116.0 mmol) was added dropwise to the flask while maintaining the temperature in the flask at 40° C. or lower.

[0259] The reaction mixture in the flask was then stirred at room temperature for 48 hours. Then, purified water (100 mL) was added to the flask. The organic phase was then separated by a separation operation. The organic phase was then washed twice with saturated aqueous sodium bicarbonate (100 mL). The solvent in the organic phase was then removed using an evaporator.

[0260] The reaction product was then placed in a four-neck flask equipped with a thermometer and a dropping funnel. 23 mg of 4-methoxyphenol (a polymerization inhibitor) was also added to the flask. The contents of the flask were then stirred at room temperature to dissolve the 4-methoxyphenol.

[0261] The diluted solution in the flask was then cooled in an ice bath. Then, while maintaining the temperature in the flask at 40°C or below, 7.63 g (75.4 mmol) of triethylamine (second modifier, base) was added dropwise to the flask. The reaction product in the flask was then stirred at room temperature for 1 hour. This treated the reaction product with a base, resulting in the formation of an acryloyl group derived from 3-chloropropionyl chloride.

[0262] Then, 1M hydrochloric acid (300 mL) was added to the reaction product solution in the flask, and the organic phase was separated by a separation operation.

[0263] The organic phase was then passed through silica gel (30 mL), and 23 mg of 4-methoxyphenol (polymerization inhibitor) was added to the organic phase, followed by concentration under reduced pressure.

[0264] As a result, 22.5 g of a colorless and transparent secondary reaction product (hereinafter referred to as Ac2.0-GSTA) was obtained. The secondary reaction product was an acetylated product and an acrylated product of GST.

[0265] In the above reaction, 1 / 3 equivalent of the mercapto groups (trifunctional) of GST were acrylated.

[0266] The secondary reaction product was analyzed by high performance liquid chromatography (HPLC). The reaction product was a polymerized component containing the following components in the following proportions:

[0267] Trithio(meth)acryloyl modified GST 5.4 mol% (LC%, formula (1)) Dithio(meth)acryloyl modified GST 31.9 mol% (LC%, formula (2), m = 2) Monothio(meth)acryloyl modified GST 48.0 mol% (LC%, formula (2), m = 1) Thio(meth)acryloyl unmodified GST 14.6 mol% (LC%, formula (3))

[0268] Based on the molecular weight of each compound, the above molar ratio was converted to a mass ratio as follows. Trithio(meth)acryloyl modified GST 5.7% by mass (formula (1)) Dithio(meth)acryloyl-modified GST 32.6% by mass (formula (2), m = 2) Monothio(meth)acryloyl modified GST 47.6% by mass (formula (2), m = 1) Unmodified thio(meth)acryloyl GST 14.1% by mass (formula (3))

[0269] Preparation example 4 (Bz2.0-GSTA) As an additive composition, the following secondary reaction product (Bz2.0-GSTA) was prepared.

[0270] (1) First reaction step A four-neck flask equipped with a stirrer, thermometer, nitrogen inlet line, and dropping funnel was charged with 48.0 g (184.3 mmol) of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (trifunctional sulfur-containing polythiol (GST)). 200 mL of dichloromethane was then added to the flask to dissolve the GST in the dichloromethane.

[0271] The flask was then slowly charged with 41.0 g of triethylamine (base catalyst, 405.4 mmol) with stirring.

[0272] The solution in the flask was then cooled in an ice bath, and 51.8 g of benzoyl chloride (first modifier, 368.5 mmol) was added dropwise to the flask while maintaining the temperature in the flask at 10° C. or lower.

[0273] After the dropwise addition was completed, the ice bath was removed and the temperature in the flask was returned to room temperature. The reaction mixture in the flask was stirred overnight. This resulted in the formation of a benzoyl group (XR' in formula (1)) derived from benzoyl chloride.

[0274] Then, 300 mL of water and 200 mL of dichloromethane were added to the reaction product solution in the flask. The organic phase was then separated by a separation operation. The organic phase was then washed with dilute hydrochloric acid. The organic phase was then washed with a saturated aqueous solution of sodium bicarbonate. The solvent in the organic phase was then distilled off using an evaporator. This yielded a crude product.

[0275] The crude product was diluted with 100 mL of dichloromethane to obtain a diluted solution. The diluted solution was passed through 100 mL of silica gel. The diluted solution was then eluted using 300 mL of dichloromethane. The eluted diluted solution was then concentrated using an evaporator. As a result, 83.4 g of the primary reaction product was obtained. The primary reaction product was a partially benzoylated GST.

[0276] In the above reaction, 2 / 3 equivalents of the mercapto groups (trifunctional) of GST were benzoylated.

[0277] (2) Second reaction step A four-neck flask equipped with a stirrer, a thermometer, a nitrogen inlet line, and a dropping funnel was charged with 30.0 g of the primary reaction product described above. Next, 50 mL of dichloromethane was added to the flask to dilute the primary reaction product with dichloromethane.

[0278] The diluted solution in the flask was then cooled in an ice bath, and 9.77 g of 3-chloropropionyl chloride (second modifier, 77.0 mmol) was added dropwise to the flask while maintaining the temperature in the flask at 40° C. or lower.

[0279] The reaction mixture in the flask was then stirred at room temperature for 48 hours. Then, purified water (100 mL) was added to the flask. The organic phase was then separated by a separation operation. The organic phase was then washed twice with saturated aqueous sodium bicarbonate (100 mL). The solvent in the organic phase was then removed using an evaporator.

[0280] The reaction product was then placed in a four-neck flask equipped with a thermometer and a dropping funnel. 30 mg of 4-methoxyphenol (a polymerization inhibitor) was also added to the flask. The contents of the flask were then stirred at room temperature to dissolve the 4-methoxyphenol.

[0281] The diluted solution in the flask was then cooled in an ice bath. Next, while maintaining the temperature in the flask at 40°C or below, 8.44 g (83.4 mmol) of triethylamine (second modifier, base) was added dropwise to the flask. The reaction product in the flask was then stirred at room temperature for 1 hour. This treated the reaction product with a base, resulting in the formation of an acryloyl group derived from 3-chloropropionyl chloride.

[0282] Then, 1M hydrochloric acid (300 mL) was added to the reaction product solution in the flask, and the organic phase was separated by a separation operation.

[0283] The organic phase was then passed through silica gel (30 mL), and 30 mg of 4-methoxyphenol (polymerization inhibitor) was added to the organic phase, followed by concentration under reduced pressure.

[0284] As a result, 32.1 g of a colorless and transparent secondary reaction product (hereinafter referred to as Bz2.0-GSTA) was obtained. The secondary reaction product was a benzoylated and acrylated product of GST.

[0285] In the above reaction, 1 / 3 equivalent of the mercapto groups (trifunctional) of GST were acrylated.

[0286] The secondary reaction product was analyzed by high performance liquid chromatography (HPLC). The reaction product was a polymerized component containing the following components in the following proportions:

[0287] Trithio(meth)acryloyl modified GST 1.6 mol% (LC%, formula (1)) Dithio(meth)acryloyl modified GST 15.2 mol% (LC%, formula (2), m = 2) Monothio(meth)acryloyl modified GST 41.7 mol% (LC%, formula (2), m = 1) Unmodified thio(meth)acryloyl GST 41.5 mol% (LC%, formula (3))

[0288] Based on the molecular weight of each compound, the above molar ratio was converted to a mass ratio as follows. Trithio(meth)acryloyl modified GST 1.3% by mass (formula (1)) Dithio(meth)acryloyl-modified GST 13.3% by mass (formula (2), m = 2) Monothio(meth)acryloyl modified GST 40.7% by mass (formula (2), m = 1) Unmodified thio(meth)acryloyl GST 44.7% by mass (formula (3))

[0289] 2. Adhesive (copolymer) Examples 1 to 16 and Comparative Examples 1 to 6 (1) Production of (meth)acrylic resin According to the formulations shown in Tables 1 to 3, (meth)acrylic resins were produced.

[0290] That is, the polymerization components were charged into a brown four-neck flask equipped with a stirrer, a thermometer, and a nitrogen inlet line according to the formulations shown in Tables 1 to 3. Furthermore, toluene (solvent, 150 parts by mass) and azoisobutyronitrile (AIBN, polymerization initiator, 0.5 parts by mass) were charged into the flask, and the contents of the flask were mixed.

[0291] The contents of the flask were then degassed and the reaction system was replaced with nitrogen by a freeze vacuum degassing method using liquid nitrogen.

[0292] Next, the temperature of the contents of the flask was raised to 60°C and stirred for 12 hours to polymerize the polymerization components. Thereafter, the temperature of the contents of the flask was lowered to room temperature, and dry air was ventilated into the flask. This resulted in a toluene solution of a (meth)acrylic resin. The toluene was removed from the resulting solution by distillation under reduced pressure to obtain a solvent-free (meth)acrylic resin.

[0293] (2) Preparation of curable composition According to the formulations shown in Tables 1 to 3, a (meth)acrylic resin (100 parts by mass) and additives were melt-kneaded. Thus, a curable composition (PC-1) was obtained. The viscosity of each curable composition (PC-1) (E-type viscometer, 25°C) was 20 Pa s or more.

[0294] In Examples 1 to 16 and Comparative Examples 1 and 2, the additive of Preparatory Example 1 or the additive composition of Preparatory Examples 2 to 4 was blended. In Comparative Examples 3 to 6, TMP-A (crosslinking agent, trimethylolpropane triacrylate) or NDDA (crosslinking agent, 1,9-nonanediol diacrylate) was blended instead of the additive or the additive composition.

[0295] In each of the examples and comparative examples, Omnirad184 (polymerization initiator, 1.0 part by mass) and KBM-5103 (acrylic group-containing silane coupling agent, 0.3 part by mass) were blended.

[0296] (3) Preparation of adhesive and laminate The above curable composition (PC-1) was sandwiched between a corona-treated polyethylene terephthalate film (thickness 38 μm, manufactured by Toray, model number: Lumirror 38S10 (hereinafter referred to as corona-treated PET film)) and a polyethylene terephthalate film (thickness 40 μm (hereinafter referred to as silicone-treated PET film)) that had been release-treated with a silicone-based release agent, and the resulting film was shaped into a sheet at a temperature of 80°C so that PC-1 had a thickness of 50 μm, producing a laminate sheet for forming an adhesive (AT-1).

[0297] Next, using an LED lamp with a wavelength of 365 nm, active energy rays (wavelength 365 nm, illuminance 100 mW / cm ) were irradiated from the corona-treated PET film side of the above-mentioned laminated sheet for forming a pressure-sensitive adhesive (AT-1). 2 , cumulative light intensity 1000mJ / cm 2 ) was irradiated. This cured the curable composition (PC-1) to obtain a pressure-sensitive adhesive.

[0298] As a result of the above, a pressure-sensitive adhesive laminate (AS-1) was obtained which was provided with a corona-treated PET film, a pressure-sensitive adhesive, and a silicone-treated PET film in that order in the thickness direction.

[0299] In addition, a laminate (AL-1) was obtained by the same procedure as above, except that a silicone-treated PET film was used instead of the corona-treated PET film, and the silicone-treated PET film, an adhesive, and the silicone-treated PET film were sequentially arranged in the thickness direction.

[0300] The laminate (AS-1) was then cut to a width of 25 mm, and the silicone-treated PET film was peeled off to expose the adhesive, which was then pressure-bonded to the surface of a glass substrate (size: 26 × 76 mm, thickness: 0.9 to 1.2 mm, manufactured by Matsunami Glass Industrial Co., Ltd., model number: S7213).

[0301] As a result of the above, a laminate (GP-1) was obtained which had the corona-treated PET film, the pressure-sensitive adhesive, and the glass substrate arranged in that order in the thickness direction.

[0302] Comparative Example 7 (1) Preparation of curable composition Butyl acrylate (99 parts by mass), acrylic acid (0.1 parts by mass), 4-hydroxybutyl acrylate (1 part by mass), Ac2.0-GSTA (10 parts by mass) obtained in Preparative Example 3, Omnirad184 (polymerization initiator, 1.0 part by mass), and KBM-5103 (acrylic group-containing silane coupling agent, 0.3 parts by mass) were mixed to obtain a curable composition (PC-2). The viscosity of the resulting curable composition (PC-2) was 20 mPa s (E-type viscometer, 25°C).

[0303] (2) Preparation of adhesive and laminate The above curable composition (PC-2) was sandwiched between a corona-treated polyethylene terephthalate film (thickness 38 μm, manufactured by Toray, model number: Lumirror 38S10 (hereinafter referred to as corona-treated PET film)) and a polyethylene terephthalate film (thickness 40 μm (hereinafter referred to as silicone-treated PET film)) that had been release-treated with a silicone-based release agent.

[0304] As in Example 1, an attempt was made to shape PC-2 into a sheet having a thickness of 50 μm at a temperature of 80°C, but the curable composition (PC-2) had such high fluidity that a sheet with a uniform thickness could not be obtained.

[0305] (4) Physical property evaluation <Refractive index nD and Abbe number> The silicone-treated PET films on both sides of the laminate (AL-1) were peeled off, and the pressure-sensitive adhesive was removed.

[0306] The refractive index and Abbe number of the adhesive were measured in accordance with ASTM D542. The results are shown in Tables 4 to 6.

[0307] More specifically, the refractive index was measured using an Abbe refractometer (DR-M4 / 1550, manufactured by Atago Co., Ltd.). The interference filters used were D-line (589 nm, manufactured by Atago Co., Ltd.; RE-16501), F-line (486 nm, manufactured by Atago Co., Ltd.; RE-16502), and C-line (656 nm, manufactured by Atago Co., Ltd.; RE-16503). The sample temperature was set to 20°C.

[0308] Thereafter, the Abbe number was calculated from the refractive index measurement results using the following formula: Formula: Abbe number = (nD-1) / (nF-nC) nD: Refractive index at the D line nF: Refractive index at F line nC: Refractive index at C line

[0309] <Storage modulus (flexibility) and glass transition temperature> The silicone-treated PET films on both sides of the laminate (AL-1) were peeled off, and the pressure-sensitive adhesive was removed.

[0310] A sample with a thickness of approximately 0.5 mm was obtained by laminating multiple adhesives.

[0311] The dynamic viscoelasticity of the samples was measured under the conditions shown below. The shear storage modulus (G') and glass transition temperature (Tg) at 25° C. were then determined. The results are shown in Tables 4 to 6.

[0312] Apparatus: MCR102 (manufactured by Anton Paar) Deformation mode; shear mode Shape: Parallel plate (8.0mmφ, gap 0.1mm) Temperature range: -30℃~50℃ Temperature rise: 5℃ / min Frequency: 1Hz Environment: dry air

[0313] <Peel strength, yellowness (b * value) and haze value> The peel strength of the laminate (GP-1) was measured in accordance with JIS Z 0237 (2000).

[0314] The temperature was 23°C, the humidity was 50% RH, the pulling speed was 300 mm / min, and the peeling direction was 180°. The peel strength was measured for the four laminates, and the average of the obtained results was calculated. The average values ​​are shown in Tables 4 to 6.

[0315] b of the above laminate (GP-1) * The color value and haze value were measured using a spectral color haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., model number COH-7700).

[0316] In addition, the glass substrate b * The b value and haze value of the silicone-treated PET film were measured by the above-mentioned method. * The thickness and haze values ​​were measured by the methods described above.

[0317] And the b of the laminate (GP-1) * From the value, the b * value and b of silicone-treated PET film * By subtracting the value, the b * The results are shown in Tables 4 to 6.

[0318] The haze value of the adhesive was calculated by subtracting the haze value of the glass substrate and the haze value of the silicone-treated PET film from the haze value of the laminate (GP-1). The results are shown in Tables 4 to 6.

[0319] <Weather resistance test> The laminate (GP-1) was subjected to a weather resistance test. More specifically, the laminate (GP-1) was exposed to ultraviolet light under the following conditions.

[0320] Light source: Xenon lamp Black panel temperature: 55℃ Humidity: 55% Rain conditions: None Irradiation conditions: 36.5W / m 2 (300-400nm) Filter: Inner / Outer = Right Light / Cira-Quartz Irradiated surface: cured film side Irradiation time: 100 hours

[0321] After the weather resistance test, the peel strength and yellowness index (b * The thickness (thickness) and haze value were measured by the methods described above. The results are shown in Tables 4 to 6.

[0322] <Heat resistance test> The laminate (GP-1) was subjected to a heat resistance test. More specifically, the laminate (GP-1) was exposed to the following conditions.

[0323] Temperature: 85℃ Humidity: 20% Test duration: 100 hours

[0324] After the heat resistance test, the peel strength and yellowness index (b * The thickness (thickness) and haze value were measured by the methods described above. The results are shown in Tables 4 to 6.

[0325] [Table 1]

[0326] [Table 2]

[0327] [Table 3]

[0328] [Table 4]

[0329] [Table 5]

[0330] [Table 6]

[0331] The abbreviations in the table are as follows: BA: butyl acrylate POB-A: m-phenoxybenzyl acrylate NMT-A: 1-naphthylmethyl acrylate AA: acrylic acid 2EHA: 2-ethylhexyl acrylate 4-HBA: 4-hydroxybutyl acrylate TMP-A: Trimethylolpropane triacrylate NDDA: 1,9-nonanediol diacrylate< / x> < / n> < / r>

Claims

1. A curable composition for obtaining a pressure-sensitive adhesive, comprising: The curable composition comprises a (meth)acrylic resin; A compound represented by the following formula (1): Contains A curable composition, wherein the content of the compound represented by the following formula (1) is less than 5.0 parts by mass relative to 100 parts by mass of the (meth)acrylic resin: 【Chemistry 1】 (In formula (1), A represents an n-valent organic group containing a sulfur atom, n represents an integer of 3 or more, and R represents a hydrogen atom or a methyl group. Each R may be the same or different.)

2. The curable composition according to claim 1, further comprising a compound represented by the following formula (2): 【Chemistry 2】 (In formula (2), A and R are defined as A and R in formula (1). X represents a single bond or a carbonyl group. R' represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an araliphatic hydrocarbon group. m represents an integer of 1 or more. 1 represents an integer of 1 or more. The sum of m and 1 represents n in formula (1). When a formula contains multiple Xs, each X may be the same as or different from another. Furthermore, when a formula contains multiple R's, each R' may be the same as or different from another.)

3. The curable composition according to claim 2, further comprising a compound represented by the following formula (3): 【Transformation 3】 (In formula (3), A and n have the same meanings as A and n in formula (1). In formula (3), X and R′ have the same meanings as X and R′ in formula (2).)

4. The curable composition according to claim 1, wherein A in formula (1) is represented by the following formula (4): 【Chemistry 4】 (In formula (4), the wavy line indicates the bonding position to the thio(meth)acryloyl group in formula (1).)

5. A pressure-sensitive adhesive comprising a cured product of the curable composition according to any one of claims 1 to 4.

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