Vinyl-based block copolymer and curable resin composition

Abstract

Provided is a vinyl-based block copolymer having a hydroxyl group, said block copolymer: containing a block structural unit comprising polymer block (A) / polymer block (B) / polymer block (A); not containing a polymer block having a glass transition temperature above 0°C; containing a monomer unit derived from a hydroxyl group-containing vinyl monomer; and having a number-average molecular weight (Mn) of 10,000-80,000, inclusive.

Description

Vinyl-based block copolymers and curable resin compositions

[0001] [Cross-reference of related applications] This application claims priority under Japanese Patent Application No. 2025-55890, filed on 28 March 2025, which is incorporated herein by reference in its entirety. This disclosure relates to vinyl block copolymers and curable resin compositions.

[0002] As curable resins used in industrial applications, vinyl copolymers having crosslinkable functional groups obtained by radical polymerization are well known. These vinyl copolymers are used as base resins in curable resin compositions and are widely used in fields such as paints, adhesives, sealants, molding materials, and cured products like rubber sheets.

[0003] As vinyl copolymers used in such curable resin compositions, Patent Documents 1 and 2 disclose vinyl copolymers having hydroxyl groups at both ends, obtained by living radical polymerization.

[0004] Japanese Patent Publication No. 2002-097238 Japanese Patent Publication No. 2014-009341

[0005] In recent years, there has been a growing demand for high levels of tensile strength, heat resistance, and weather resistance in various products, including automotive parts, electrical appliances, medical-related products, and civil engineering and construction materials such as paints, packings, gaskets, and hoses, as well as in adhesive raw materials and sealing materials. In particular, for applications where outdoor use is anticipated, such as in construction, it is desirable that the cured product obtained by curing a curable resin composition has weather resistance that can withstand the dynamic deformation of the cured product itself caused by temperature, humidity, etc.

[0006] This disclosure has been made in view of the above circumstances, and its primary purpose is to provide a vinyl-based block copolymer that can produce a cured product with excellent tensile properties, heat resistance, and weather resistance.

[0007] As a result of diligent research to solve the above problems, the present inventors have found that by using a vinyl-based block copolymer having a specific structure and physical properties, a cured product with excellent tensile properties, heat resistance, and weather resistance can be obtained. Specifically, the present disclosure provides the following vinyl-based block copolymer and curable resin composition.

[0008] [1] A vinyl block copolymer having hydroxyl groups, comprising block structural units consisting of polymer block (A) / polymer block (B) / polymer block (A), not comprising polymer blocks having a glass transition temperature above 0°C, comprising monomer units derived from a hydroxyl group-containing vinyl monomer, and having a number average molecular weight (Mn) of 10,000 or more and 80,000 or less. [2] The vinyl block copolymer according to [1], wherein the hydroxyl value is 1.0 to 25.0 mgKOH / g. [3] The vinyl block copolymer according to [1] or [2], wherein the average number of hydroxyl groups per molecule is 1.8 or more. [4] The vinyl block copolymer according to any one of [1] to [3], wherein the molecular weight distribution (Mw / Mn), expressed as the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), is 2.20 or less. [5] A vinyl block copolymer according to any one of [1] to [4], wherein monomer units derived from an alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms in the ester portion are present in an amount of 50 to 99.5% by mass relative to the total amount of monomer units constituting the vinyl block copolymer. [6] A vinyl block copolymer according to any one of [1] to [5], wherein the hydroxyl group-containing vinyl monomer is an alkyl (meth)acrylate having a hydroxyl group. [7] A vinyl block copolymer according to any one of [1] to [6], wherein the content ratio of monomer units derived from the hydroxyl group-containing vinyl monomer is 4 to 30% by mass relative to the total amount of monomer units constituting the polymer block (A). [8] A vinyl block copolymer according to any one of [1] to [7], wherein the content ratio of monomer units derived from the hydroxyl group-containing vinyl monomer is less than 4% by mass relative to the total amount of monomer units constituting the polymer block (B). [9] The solubility parameter value (SP value) of the polymer block (A) is set to X [cal / cm²]３ ] １／２ The SP value of the polymer block (B) is Y [cal / cm²]. ３ ] １／２ A vinyl block copolymer according to any one of [1] to [8], wherein X is 9.7 or more and 10.5 or less, and the ratio of X to Y (X / Y) is greater than 1.0 and 1.3 or less.

[10] A vinyl block copolymer according to any one of [1] to [9], wherein the mass ratio of polymer block (A) to polymer block (B), when expressed as polymer block (A):polymer block (B), is 1:100 to 50:50.

[11] A curable resin composition containing a vinyl block copolymer according to any one of [1] to

[10] and a polyfunctional isocyanate compound.

[12] A curable resin composition according to

[11] for use as a sealant, adhesive, tack, coating agent, or paint.

[0009] According to the vinyl block copolymer of this disclosure, a cured product with excellent tensile properties, heat resistance, and weather resistance can be obtained.

[0010] The details of this disclosure are described below. In this specification, "(meth)acrylic" means acrylic and / or methacrylic. "(meth)acrylate" means acrylate and / or methacrylate. "(meth)acryloyl" means acryloyl and / or methacryloyl. Unless otherwise specified, each component may be used alone or in combination of two or more components.

[0011] <<Vinyl Block Copolymer>> The vinyl block copolymer of this disclosure (hereinafter also referred to as "vinyl copolymer (P)") is a molecular aggregate containing a polymer having a hydroxyl group, and includes block structural units consisting of polymer block (A) / polymer block (B) / polymer block (A). Furthermore, vinyl copolymer (P) does not contain polymer blocks with a glass transition temperature (Tg) above 0°C, contains monomer units derived from a hydroxyl group-containing vinyl monomer, and has a number average molecular weight (Mn) of 10,000 or more and 80,000 or less.

[0012] (Block composition) The vinyl copolymer (P) only needs to contain block structural units consisting of polymer block (A) / polymer block (B) / polymer block (A). Here, polymer block (A) and polymer block (B) are polymer blocks with different monomer compositions. "Different monomer compositions" in two polymer blocks includes embodiments where the types of monomers constituting the polymer blocks are the same but the monomer composition ratios are different, and embodiments where the types of monomers constituting the polymer blocks are different between the polymer blocks.

[0013] Specific examples of vinyl copolymers (P) containing block structural units consisting of polymer block (A) / polymer block (B) / polymer block (A) include (A)-(B)-(A) triblock bodies consisting of polymer block (A) / polymer block (B) / polymer block (A); (A)-(B)-(A)-(B) tetrablock bodies consisting of polymer block (A) / polymer block (B) / polymer block (A) / polymer block (B); and (A)-(B)-(A)-(B)-(A) pentablock bodies consisting of polymer block (A) / polymer block (B) / polymer block (A) / polymer block (B) / polymer block (A). Furthermore, vinyl copolymers (P) may further contain polymer blocks (C) other than polymer block (A) and polymer block (B).

[0014] However, each polymer block constituting the vinyl copolymer (P) has a glass transition temperature (Tg) of 0°C or lower. That is, the vinyl copolymer (P) does not contain any polymer blocks with a glass transition temperature (Tg) exceeding 0°C. As a result, the vinyl copolymer (P) has good flexibility and it is easy to obtain a cured product with excellent weather resistance. The Tg of each polymer block is a value measured by differential scanning calorimetry (DSC). More specifically, the Tg of each polymer block can be determined by synthesizing a polymer made up of the monomers constituting the polymer block to be measured and measuring the Tg of that polymer by DSC.

[0015] A vinyl copolymer (P) is preferably a (A)-(B)-(A) triblock, as this allows for manufacturing ease while maintaining a minimal number of blocks, and enables the production of a polymer exhibiting excellent tensile properties, heat resistance, and weather resistance. In this structure, it is believed that polymer block (A) acts as a crosslinking segment by introducing a relatively large amount of monomer units derived from the hydroxyl group-containing vinyl monomer into polymer block (A). This is advantageous because it facilitates the formation of a uniform crosslinking structure while ensuring molecular weight between crosslinking points, thereby increasing the mechanical strength, heat resistance, and weather resistance of the resulting cured product.

[0016] (Molecular Weight Characteristics) The number-average molecular weight (Mn) of vinyl copolymers (P), measured by gel permeation chromatography (GPC) in terms of polystyrene, is in the range of 10,000 to 80,000. If Mn is less than 10,000, the tensile properties, heat resistance, and weather resistance of cured products made from vinyl copolymers tend to be insufficient. Furthermore, if the Mn of the vinyl copolymer exceeds 80,000, good fluidity and coating properties cannot be ensured.

[0017] From the viewpoint of obtaining a cured product with excellent tensile properties, heat resistance, and weather resistance, the Mn of the vinyl copolymer (P) is preferably 15,000 or more, more preferably 18,000 or more, even more preferably 20,000 or more, and even more preferably 25,000 or more. Regarding the upper limit of the Mn of the vinyl copolymer (P), from the viewpoint of ensuring the fluidity of the polymer, it is preferably 75,000 or less, more preferably 70,000 or less, even more preferably 65,000 or less, and even more preferably 60,000 or less. The preferred range for the Mn of the vinyl copolymer (P) can be set by appropriately combining the preferred upper and lower limits described above. The Mn of the vinyl copolymer (P) is preferably 15,000 to 75,000, more preferably 18,000 to 70,000, even more preferably 20,000 to 65,000, and even more preferably 25,000 to 60,000.

[0018] Furthermore, for the vinyl copolymer (P), the weight-average molecular weight (Mw) in polystyrene equivalent, as measured by GPC, is preferably in the range of 15,000 to 100,000. When Mw is 15,000 or higher, the tensile properties, weather resistance, and heat resistance of the cured product can be sufficiently high when the cured product is manufactured using the vinyl copolymer (P). Also, when the Mw of the vinyl copolymer (P) is 100,000 or lower, good fluidity and coating properties can be ensured.

[0019] From the viewpoint of improving the tensile properties, heat resistance, and weather resistance of the cured product, the Mw of the vinyl copolymer (P) is more preferably 18,000 or more, even more preferably 20,000 or more, even more preferably 22,000 or more, and even more preferably 25,000 or more. Regarding the upper limit of the Mw of the vinyl copolymer (P), from the viewpoint of ensuring the fluidity of the polymer, it is more preferably 95,000 or less, even more preferably 90,000 or less, and even more preferably 85,000 or less. The range of Mw for the vinyl copolymer (P) is more preferably 18,000 to 95,000, even more preferably 20,000 to 90,000, and even more preferably 22,000 to 85,000.

[0020] For vinyl copolymers (P), the molecular weight distribution (Mw / Mn), expressed as the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), is preferably 2.20 or less, more preferably 2.10 or less, even more preferably 2.00 or less, even more preferably 1.90 or less, even more preferably 1.70 or less, and even more preferably 1.55 or less, from the viewpoint of obtaining a cured product with excellent tensile properties (elongation at break and breaking strength), heat resistance, and weather resistance. The lower limit of the molecular weight distribution (Mw / Mn) is not particularly limited, but may be, for example, 1.05 or more, or 1.10 or more.

[0021] (Glass Transition Temperature) The glass transition temperature (Tg) of the vinyl copolymer (P) is preferably -100°C or higher and 0°C or lower. If the Tg of the vinyl copolymer (P) is -100°C or higher, a cured product exhibiting good heat resistance is easily obtained, and if it is 0°C or lower, a cured product exhibiting good tensile properties and weather resistance is easily obtained. In terms of easily obtaining a cured product with a good balance of improved tensile properties, weather resistance and heat resistance, the Tg of the vinyl copolymer (P) is more preferably -90°C or higher, even more preferably -80°C or higher, even more preferably -70°C or higher, and even more preferably -65°C or higher. Furthermore, the Tg of the vinyl copolymer (P) is more preferably -10°C or lower, even more preferably -20°C or lower, even more preferably -25°C or lower, and even more preferably -30°C or lower. In this specification, the Tg of the vinyl copolymer (P) is a value measured by differential scanning calorimetry (DSC). Details of the measurement method are as described in the examples below.

[0022] (Viscosity) The viscosity of the vinyl copolymer (P) is preferably 10 to 2,000 Pa·s. When the vinyl copolymer (P) has a viscosity within the above range, it is possible to obtain a polymer with good tensile properties while having good fluidity and coating properties. From the viewpoint of obtaining a polymer with sufficiently good tensile properties, the viscosity of the vinyl copolymer (P) is more preferably 15 Pa·s or more, even more preferably 20 Pa·s or more, and even more preferably 25 Pa·s or more. Furthermore, from the viewpoint of ensuring the fluidity and coating properties of the vinyl copolymer (P), the viscosity of the vinyl copolymer (P) is more preferably 1,800 Pa·s or less, even more preferably 1,600 Pa·s or less, and even more preferably 1,400 Pa·s or less. The viscosity of the vinyl copolymer (P) is the value measured by an E-type viscometer at 25°C. Details of the viscosity measurement method are as described in the examples below.

[0023] (Hydrogen Value) The hydroxyl value of the vinyl copolymer (P) is preferably 1.0 mg KOH / g or more and 25.0 mg KOH / g or less. When the hydroxyl value of the vinyl copolymer (P) is 1.0 mg KOH / g or more, a polymer with sufficient crosslinking points can be formed, and a cured product with sufficient tensile properties, heat resistance and weather resistance can be obtained. Furthermore, when the hydroxyl value of the vinyl copolymer (P) is 25.0 mg KOH / g or less, a cured product exhibiting good elongation at break can be obtained. From these viewpoints, the hydroxyl value of the vinyl copolymer (P) is more preferably 1.5 mg KOH / g or more, even more preferably 2.0 mg KOH / g or more, and even more preferably 3.0 mg KOH / g or more. The upper limit of the hydroxyl value of the vinyl copolymer (P) is more preferably 20.0 mg KOH / g or less, even more preferably 18.0 mg KOH / g or less, and even more preferably 15.0 mg KOH / g or less. In this specification, "hydroxyl value" is a value measured by potentiometric titration in accordance with "7. Hydroxyl Value" of JIS K 0070 (1992). Details of the measurement conditions are as described in the examples below.

[0024] The preferred range for the hydroxyl value of the vinyl copolymer (P) can be set by appropriately combining the preferred upper and lower limits described above. Specifically, the hydroxyl value of the vinyl copolymer (P) is more preferably 1.5 mg KOH / g or more and 20.0 mg KOH / g or less, even more preferably 2.0 mg KOH / g or more and 18.0 mg KOH / g or less, and even more preferably 3.0 mg KOH / g or more and 15.0 mg KOH / g or less.

[0025] (Average number of hydroxyl groups) It is preferable that the average number of hydroxyl groups per molecule of the vinyl copolymer (P) is 1.8 or more. When the average number of hydroxyl groups per molecule of the vinyl copolymer (P) is 1.8 or more, the tensile properties, heat resistance, and weather resistance of the cured vinyl copolymer (P) can be further improved. From the viewpoint of obtaining a cured product with superior tensile properties, heat resistance, and weather resistance, it is more preferable that the average number of hydroxyl groups per molecule of the vinyl copolymer (P) is 2.0 or more, even more preferable that it is 2.2 or more, even more preferable that it is 2.4 or more, even more preferable that it is 2.7 or more, and even more preferable that it is 3.0 or more. Furthermore, in terms of being able to make the elongation at break of the cured product obtained using the vinyl copolymer (P) even better, it is preferable that the average number of hydroxyl groups per molecule of the vinyl copolymer (P) is 10.0 or less, more preferable that it is 9.5 or less, even more preferable that it is 9.0 or less, and even more preferable that it is 8.0 or less.

[0026] The preferred range for the average number of hydroxyl groups per molecule in the vinyl copolymer (P) can be set by appropriately combining the upper and lower limits described above. Specifically, the average number of hydroxyl groups per molecule in the vinyl copolymer (P) is preferably 1.8 to 10.0, more preferably 2.0 to 9.5, even more preferably 2.2 to 9.0, and most preferably 2.4 to 8.0.

[0027] In this specification, the average number of hydroxyl groups in a vinyl copolymer (P) can be calculated from the ratio of monomer units derived from hydroxyl group-containing monomers in the vinyl copolymer (P), which is determined by gas chromatography (GC) measurement, and the number-average molecular weight (Mn) of the vinyl copolymer (P), which is determined by GPC measurement. Details of the measurement and calculation methods are described in the examples below.

[0028] (Monomers) The vinyl copolymer (P) contains monomer units derived from the hydroxyl group-containing vinyl monomer (hereinafter also referred to as "hydroxyl group-containing vinyl units"). As the hydroxyl group-containing vinyl monomer, (meth)acrylic monomers having hydroxyl groups can be preferably used because they can improve the heat resistance and weather resistance of the polymer and offer a high degree of freedom in monomer selection.

[0029] Specific examples of hydroxyl group-containing vinyl monomers include alkyl (meth)acrylates having hydroxyl groups; mono(meth)acrylates of polyalkylene glycols; and the like. Specific examples of alkyl (meth)acrylates having hydroxyl groups include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Specific examples of mono(meth)acrylates of polyalkylene glycols include mono(meth)acrylates of polyethylene glycol and polypropylene glycol. Among these, alkyl (meth)acrylates having hydroxyl groups are particularly preferred because they easily yield vinyl copolymers (P) with a sufficiently low glass transition temperature (Tg) and excellent fluidity.

[0030] In the vinyl copolymer (P), the content ratio of hydroxyl group-containing vinyl units is preferably 0.2% by mass or more and 10% by mass or less, based on the total amount of monomer units constituting the vinyl copolymer (P). By setting the content ratio of hydroxyl group-containing vinyl units in the vinyl copolymer (P) within the above range, a cured product with higher heat resistance and weather resistance can be obtained while exhibiting good tensile properties. From these viewpoints, the content ratio of hydroxyl group-containing vinyl units in the vinyl copolymer (P) is more preferably 0.5% by mass or more, and even more preferably 0.7% by mass or more, based on the total amount of monomer units constituting the vinyl copolymer (P). Further, the content ratio of hydroxyl group-containing vinyl units is more preferably 8% by mass or less, even more preferably 5% by mass or less, and still more preferably 3.5% by mass or less, based on the total amount of monomer units constituting the vinyl copolymer (P).

[0031] The preferred range of the content ratio of hydroxyl group-containing vinyl units in the vinyl copolymer (P) can be set by appropriately combining the above-mentioned preferred upper limit values and lower limit values. Specifically, the content ratio of hydroxyl group-containing vinyl units is more preferably 0.5% by mass or more and 8% by mass or less, and even more preferably 0.7% by mass or more and 5% by mass or less.

[0032] ・Other vinyl monomers The vinyl copolymer (P) may contain monomer units derived from a vinyl monomer different from the hydroxyl group-containing vinyl monomer (hereinafter also referred to as "other vinyl monomer") together with hydroxyl group-containing vinyl units. Other vinyl monomers are not particularly limited as long as they are monomers copolymerizable with the hydroxyl group-containing vinyl monomer.

[0033] Specific examples of other vinyl monomers include alkyl (meth)acrylates, aliphatic cyclic esters of (meth)acrylic acid, aromatic esters of (meth)acrylic acid, and the following general formula (1): CH ２ =CR １ -C(=O)O-(R ２ O) ｎ -R ３   ...(1) (in general formula (1), R １ represents a hydrogen atom or a methyl group, and R ２represents a linear or branched alkylene group having 2 to 6 carbon atoms, R ３ represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms. n represents an integer of 1 to 100.), a crosslinkable silyl group-containing vinyl compound, an unsaturated carboxylic acid, an unsaturated acid anhydride, an epoxy group-containing vinyl compound, a primary or secondary amino group-containing vinyl compound, an oxazoline group-containing vinyl compound, an isocyanate group-containing vinyl compound, a styrene-based compound, a maleimide compound, an amide group-containing vinyl compound, and a fluorine-containing (meth)acrylic acid ester compound.

[0034] Specific examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, icosyl (meth)acrylate, and the like.

[0035] Specific examples of aliphatic cyclic esters of (meth)acrylic acid include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and the like.

[0036] Specific examples of aromatic esters of (meth)acrylic acid include phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxymethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, and 3-phenoxypropyl (meth)acrylate.

[0037] For compounds represented by the above general formula (1), if n in the above general formula (1) is 1, the compound represented by the above general formula (1) has an oxyalkylene structure such as an oxyethylene chain, an oxypropylene chain, and an oxybutylene chain. Specific examples of compounds in the above general formula (1) where n is 1 (i.e., (meth)acrylate alkoxyalkyl ester compounds) include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, n-propoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, ethoxypropyl (meth)acrylate, n-propoxypropyl (meth)acrylate, n-butoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, n-propoxybutyl (meth)acrylate, and n-butoxybutyl (meth)acrylate.

[0038] When n in the above general formula (1) is 2 or more, the compound represented by the above general formula (1) has a polyoxyalkylene structure such as a polyoxyethylene chain, a polyoxypropylene chain, and a polyoxybutylene chain. Furthermore, when n is 2 or more, there are two or more R in the above general formula (1). ２ These elements may be identical or different. That is, compounds in which n in the above general formula (1) is 2 or more may have different types of polyoxyalkylene structures in one molecule, such as a block structure consisting of polyoxyethylene / polyoxypropylene.

[0039] Specific examples of compounds in which n in the above general formula (1) is 2 or more include methoxypolyethylene glycol (meth)acrylate, lauroxypolyethylene glycol (meth)acrylate, stearoxypolyethylene glycol (meth)acrylate, octoxypolyethylene glycol polypropylene glycol (meth)acrylate, nonylphenoxypolypropylene glycol (meth)acrylate, and phenoxypolyethylene glycol polypropylene glycol (meth)acrylate.

[0040] Specific examples of crosslinkable silyl group-containing vinyl compounds include vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyldimethylmethoxysilane; (meth)acrylate trimethoxysilylpropyl, (meth)acrylate triethoxysilylpropyl, (meth)acrylate methyldimethoxysilylpropyl, (meth)acrylate dimethylmethoxysilylpropyl, (meth)acrylate trimethoxysilylmethyl, (meth)acrylate methyldimethoxysilylmethyl, (meth)acrylate 8-(trimethoxysilyl) Examples include (meth)acrylic acid esters containing alkoxysilyl groups such as octyl; aromatic vinyl group-containing alkoxysilanes such as p-styryltrimethoxysilane, p-styrylmethyldimethoxysilane, p-styryldimethylmethoxysilane, p-styryltriethoxysilane, p-styrylmethyldiethoxysilane, and p-styryldimethylethoxysilane; alkoxysilyl group-containing vinyl ethers such as trimethoxysilylpropyl vinyl ether; and alkoxysilyl group-containing vinyl esters such as trimethoxysilylundecanoate vinyl.

[0041] Specific examples of unsaturated carboxylic acids include (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and monoalkyl esters of unsaturated dicarboxylic acids (monoalkyl esters of maleic acid, fumaric acid, itaconic acid, citraconic acid, etc.). Specific examples of unsaturated acid anhydrides include maleic anhydride, itaconic anhydride, and citraconic anhydride.

[0042] Specific examples of epoxy group-containing vinyl compounds include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0043] Specific examples of primary or secondary amino group-containing vinyl compounds include amino group-containing (meth)acrylic acid esters such as aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, N-methylaminoethyl (meth)acrylate, and N-ethylaminoethyl (meth)acrylate; and amino group-containing (meth)acrylamides such as aminoethyl (meth)acrylamide, aminopropyl (meth)acrylamide, N-methylaminoethyl (meth)acrylamide, and N-ethylaminoethyl (meth)acrylamide.

[0044] Specific examples of oxazoline group-containing vinyl compounds include 2-isopropenyl-2-oxazoline and 2-vinyl-2-oxazoline. Specific examples of isocyanate group-containing vinyl compounds include 2-isocyanatoethyl (meth)acrylate and (meth)acryloyl isocyanate.

[0045] Specific examples of styrene compounds include styrene, α-methylstyrene, β-methylstyrene, vinylxylene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, p-n-butylstyrene, p-isobutylstyrene, p-t-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, o-isopropenylphenol, o-vinylbenzoic acid, m-vinylbenzoic acid, p-vinylbenzoic acid, divinylbenzene, and vinylnaphthalene.

[0046] Specific examples of maleimide compounds include maleimide and N-substituted maleimide compounds. Examples of N-substituted maleimide compounds include N-methylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-isopropylmaleimide, N-n-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide, N-pentylmaleimide, N-hexylmaleimide, N-heptylmaleimide, N-octylmaleimide, N-laurylmaleimide, and N-stearylmaleimide, which are N-alkyl-substituted maleimide compounds; and N-cyclopentylmaleimide. Examples include maleimide and N-cycloalkyl-substituted maleimide compounds such as N-cyclohexylmaleimide; and N-aryl-substituted maleimide compounds such as N-phenylmaleimide, N-(4-hydroxyphenyl)maleimide, N-(4-acetylphenyl)maleimide, N-(4-methoxyphenyl)maleimide, N-(4-ethoxyphenyl)maleimide, N-(4-chlorophenyl)maleimide, N-(4-bromophenyl)maleimide, and N-benzylmaleimide.

[0047] Specific examples of amide group-containing vinyl compounds include (meth)acrylamide, (meth)acrylamide derivatives, and N-vinylamide monomers. Among these, specific examples of (meth)acrylamide derivatives include tert-butyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and (meth)acryloylmorpholine. Specific examples of N-vinylamide monomers include N-vinylacetamide, N-vinylformamide, and N-vinylisobutylamide.

[0048] Specific examples of fluorine-containing (meth)acrylic acid ester compounds include trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, perfluoroethylene, perfluoropropylene, and vinylidene fluoride.

[0049] Other vinyl monomers include, in addition to those mentioned above, vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinyl cinnamate; alkenes such as ethylene and propylene; conjugated dienes such as butadiene and isoprene; and vinyl chloride, vinylidene chloride, and allyl chloride.

[0050] In terms of being able to produce a polymer with excellent weather resistance and flexibility, it is preferable that the vinyl copolymer (P) contains monomer units derived from alkyl (meth)acrylate. Furthermore, it is preferable that the alkyl (meth)acrylate constituting the vinyl copolymer (P) contains alkyl (meth)acrylate (hereinafter also referred to as "C1-8 alkyl (meth)acrylate") in which the alkyl group (R) contained in the ester portion (-COOR) has 1 to 8 carbon atoms, in order to moderately lower the Tg of the vinyl copolymer (P), thereby providing good weather resistance and heat resistance, and to increase flexibility.

[0051] In a vinyl copolymer (P), the content of structural units derived from C1-8 (meth)acrylate alkyl ester is preferably 50% by mass or more and 99.5% by mass or less, relative to the total amount of monomer units constituting the vinyl copolymer (P), from the viewpoint of obtaining a vinyl copolymer (P) with excellent weather resistance and heat resistance. More preferably, the content of structural units derived from C1-8 (meth)acrylate alkyl ester is 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 85% by mass or more, relative to the total amount of monomer units constituting the vinyl copolymer (P). Furthermore, the content of structural units derived from C1-8 (meth)acrylate alkyl ester is more preferably 99.2% by mass or less, and even more preferably 99.0% by mass or less, relative to the total amount of monomer units constituting the vinyl copolymer (P).

[0052] When preparing a curable resin composition containing a vinyl copolymer (P), if compatibility with other components blended into the curable resin composition is considered, the vinyl copolymer (P) may contain monomer units derived from an alkyl (meth)acrylate (hereinafter also referred to as "alkyl (meth)acrylate with 10 or more C10") or an aliphatic cyclic ester of (meth)acrylic acid, which has an alkyl group with 10 or more C10 in the ester portion. When the vinyl copolymer (P) contains monomer units derived from an alkyl (meth)acrylate (with 10 or more C10) or an aliphatic cyclic ester of (meth)acrylic acid, the content of such monomer units may be, for example, 1 to 50% by mass, 2 to 45% by mass, or 5 to 40% by mass, based on the total amount of monomer units constituting the vinyl copolymer (P).

[0053] (Polymer block (A)) A preferred embodiment of the vinyl copolymer (P) is a block structure unit consisting of polymer block (A) / polymer block (B) / polymer block (A), in which polymer block (A) contains hydroxyl group-containing vinyl units, and polymer block (B) has a lower proportion of hydroxyl group-containing vinyl units than polymer block (A). Concentrating hydroxyl groups as crosslinking points on polymer block (A) is preferable from the viewpoint of forming a uniform crosslinked structure in the cured product obtained using the vinyl copolymer (P).

[0054] In polymer block (A), the content of hydroxyl group-containing vinyl units is preferably 4% by mass or more and 30% by mass or less, relative to the total amount of monomer units constituting polymer block (A). A content of 4% by mass or more of hydroxyl group-containing vinyl units in polymer block (A) is preferable because it allows for sufficient improvement of tensile properties, heat resistance, and weather resistance. Furthermore, a content of 30% by mass or less of hydroxyl group-containing vinyl units ensures sufficient flexibility and weather resistance of the vinyl copolymer (P). From these viewpoints, the content of hydroxyl group-containing vinyl units in polymer block (A) is more preferably 5% by mass or more, and even more preferably 5.5% by mass or more, relative to the total amount of monomer units constituting polymer block (A). Regarding the upper limit of crosslinkable group-containing vinyl units, it is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, relative to the total amount of monomer units constituting polymer block (A).

[0055] Examples of monomers constituting polymer block (A) include hydroxyl group-containing vinyl monomers, as well as the compounds exemplified as specific examples of monomers constituting vinyl copolymer (P). Of these, polymer block (A) preferably contains monomer units derived from alkyl (meth)acrylate, and more preferably contains at least monomer units derived from C1-8 alkyl (meth)acrylate.

[0056] In polymer block (A), the content of structural units derived from C1-8 (meth)acrylate alkyl ester is preferably 50% by mass or more, relative to the total amount of monomer units constituting polymer block (A), from the viewpoint of obtaining a vinyl copolymer (P) with excellent heat resistance and weather resistance. The proportion of structural units derived from C1-8 (meth)acrylate alkyl ester is more preferably 55% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more. The upper limit of the proportion of structural units derived from C1-8 (meth)acrylate alkyl ester in polymer block (A) is, for example, 99.5% by mass or less, preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less, from the viewpoint of introducing a sufficient amount of hydroxyl groups.

[0057] From the viewpoint of improving the tensile properties, heat resistance, and weather resistance of the cured product by forming a uniform crosslinked structure, it is preferable to relatively increase the amount of hydroxyl groups introduced into the polymer block (A). From this viewpoint, the solubility parameter value (SP value) of the polymer block (A) is preferably 9.7 or more and 10.5 or less, more preferably 9.8 or more and 10.5 or less, and even more preferably 9.9 or more and 10.5 or less. In this specification, the SP value of the polymer is the value calculated by the Fedors method (unit: [cal / cm³]). ３ ] １／２ ) The details of the method for measuring the SP value of the polymer follow the method described in the examples below.

[0058] (Polymer block (B)) Examples of monomers constituting polymer block (B) include the compounds exemplified as specific examples of monomers constituting vinyl copolymer (P). Polymer block (B) is preferable in that it allows for the production of a vinyl copolymer with excellent flexibility, and among the monomers exemplified above, alkyl (meth)acrylate is the main monomer.

[0059] In polymer block (B), the content of monomer units derived from alkyl (meth)acrylate is preferably 50% by mass or more, relative to the total amount of monomer units constituting polymer block (B), in order to obtain a vinyl copolymer with excellent tensile properties. More preferably, the content of monomer units derived from alkyl (meth)acrylate in polymer block (B) is 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, relative to the total amount of monomer units constituting polymer block (B).

[0060] To enhance the flexibility of the vinyl copolymer (P), it is preferable that the polymer block (B) contains structural units derived from C1-8 (meth)acrylate alkyl ester.

[0061] In polymer block (B), the content of structural units derived from C1-8 (meth)acrylate alkyl ester is preferably 50% by mass or more, relative to the total amount of monomer units constituting polymer block (B), from the viewpoint of obtaining a vinyl copolymer (P) with excellent heat resistance and weather resistance. More preferably, the content of structural units derived from C1-8 (meth)acrylate alkyl ester is 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The upper limit of the content of structural units derived from C1-8 (meth)acrylate alkyl ester in polymer block (B) is, for example, 99.5% by mass or less, and preferably 99% by mass or less.

[0062] In polymer block (B), the content of hydroxyl group-containing vinyl units is preferably less than 4% by mass of the total amount of monomer units constituting polymer block (B). When the content of hydroxyl group-containing vinyl units in polymer block (B) is less than 4% by mass, a sufficient distance between crosslinking points can be secured, thereby significantly improving tensile properties, heat resistance, and weather resistance. From this viewpoint, the content of hydroxyl group-containing vinyl units in polymer block (B) is more preferably 2% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, based on the total amount of monomer units constituting polymer block (B).

[0063] From the viewpoint of further improving the tensile properties, heat resistance, and weather resistance of the cured product by ensuring a sufficient distance between crosslinking points and forming a uniform crosslinked structure, it is preferable to minimize the amount of hydroxyl groups introduced into the polymer block (B). Furthermore, the solubility parameter value (SP value) of the polymer block (B) is preferably 9.3 or more and 9.9 or less, more preferably 9.4 or more and 9.8 or less, and even more preferably 9.5 or more and 9.8 or less.

[0064] For polymer block (A) and polymer block (B), the SP value of polymer block (A) is given by X [cal / cm²]. ３ ] １／２ The SP value of polymer block (B) is Y [cal / cm²] ３ ] １／２ In this case, it is preferable that X is 9.7 or more and 10.5 or less, and that the ratio of X to Y (X / Y) is greater than 1.0 and 1.3 or less. When the SP values ​​of polymer block (A) and polymer block (B) satisfy the above relationship, polymer block (A) acts as a crosslinking segment, making it easier to form a uniform crosslinked structure while ensuring the distance between crosslinking points. As a result, it is preferable that a cured product with excellent tensile properties, heat resistance and weather resistance can be obtained. Furthermore, from the above viewpoint, it is more preferable that the ratio of X to Y (X / Y) is greater than 1.0 and 1.2 or less, even more preferable that it is greater than 1.0 and 1.15 or less, and even more preferable that it is greater than 1.0 and 1.1 or less.

[0065] In the vinyl copolymer (P), the ratio of polymer block (A) to polymer block (B) is not particularly limited. In order to ensure a sufficient distance between crosslinking points in the vinyl copolymer (P), thereby obtaining a cured product with excellent tensile properties, heat resistance, and weather resistance, the mass ratio of polymer block (A) to polymer block (B), expressed as polymer block (A):polymer block (B), is preferably 1:100 to 50:50. Furthermore, from the above viewpoint, the mass ratio of polymer block (A) to polymer block (B) is more preferably 5:95 to 40:60, even more preferably 10:90 to 30:70, and even more preferably 10:90 to 20:80.

[0066] <Production of Vinyl Copolymer (P)> The polymerization method for obtaining vinyl copolymer (P) is not particularly restricted as long as a polymer containing block structural units consisting of polymer block (A) / polymer block (B) / polymer block (A) can be obtained. For example, various controlled polymerization methods such as living radical polymerization and living anionic polymerization can be used to obtain vinyl block copolymers with precisely controlled molecular weight and molecular weight distribution. Alternatively, vinyl block copolymers may be produced by coupling polymers having functional groups. Of these, production by living radical polymerization is preferred because it is easy to operate and can be applied to a wide range of monomers. Furthermore, living radical polymerization can reduce the content of metal components that may affect durability at high temperatures, thereby obtaining a cured product with excellent heat resistance.

[0067] When producing vinyl copolymers (P) by living radical polymerization, known polymerization methods can be used as the living radical polymerization method. Specific examples of living radical polymerization methods include exchange chain transfer type living radical polymerization, bond-dissociation type living radical polymerization, and atom transfer type living radical polymerization. Of these, the exchange chain transfer type living radical polymerization method is preferred because it can be applied to the widest range of vinyl monomers and offers excellent polymerization control. From the viewpoint of ease of implementation, the reversible addition-cleavage chain transfer polymerization (RAFT) method is particularly preferred.

[0068] In the RAFT method, polymerization proceeds via a reversible chain transfer reaction in the presence of a living radical polymerization control agent (RAFT agent) and a polymerization initiator. Various known RAFT agents can be used as RAFT agents, such as dithioester compounds, xantate compounds, trithiocarbonate compounds, and dithiocarbamate compounds. Of these, dithioester compounds or trithiocarbonate compounds are preferred, and trithiocarbonate compounds are more preferred, due to their excellent polymerization control properties for (meth)acrylic acid ester compounds. Examples of compounds having a trithiocarbonate group include, for example, S,S-dibenzyl trithiocarbonate, bis[4-(2,3-dihydroxypropoxycarbonyl)benzyl]trithiocarbonate, bis[4-(2-hydroxyethoxycarbonyl)benzyl]trithiocarbonate, and 1,4-bis(alkylsulfanylthiocarbonylsulfanylmethyl)benzene (for example, 1,4-bis(n-dodecylsulfanylthiocarbonylsulfanylmethyl)benzene, etc.).

[0069] As the RAFT agent, a monofunctional type having only one active site per molecule may be used, or a polyfunctional type having two or more active sites per molecule may be used. It is preferable to use a bifunctional RAFT agent for polymerization because it is possible to efficiently obtain a block copolymer of an (A)-(B)-(A) triblock consisting of polymer block (A) / polymer block (B) / polymer block (A). The amount of RAFT agent used can be appropriately adjusted depending on the monomer and type of RAFT agent used.

[0070] For example, when obtaining an (A)-(B)-(A) triblock product consisting of polymer block (A) / polymer block (B) / polymer block (A) by living radical polymerization using a bifunctional RAFT agent (e.g., S,S-dibenzyltrithiocarbonate), the target product can be efficiently obtained by a method that includes the following two steps as the polymerization step for polymerizing the vinyl monomer. That is, in the first step (first polymerization step), the vinyl monomer is polymerized in the presence of the RAFT agent and the polymerization initiator to obtain polymer block (A). Then, in the second step (second polymerization step), the vinyl monomer is polymerized in the presence of the polymer block (A) obtained in the first polymerization step and the polymerization initiator to form polymer block (B). This makes it possible to obtain an (A)-(B)-(A) triblock product consisting of polymer block (A) / polymer block (B) / polymer block (A). Furthermore, by a similar method, a higher-order block copolymer (for example, an (A)-(B)-(A)-(B)-(A) pentablock) can be obtained as a vinyl-based block copolymer.

[0071] As polymerization initiators, known radical polymerization initiators such as azo compounds, organic peroxides, and persulfates can be used. Among these, azo compounds are preferred because they are easy to handle safely and less likely to cause side reactions during radical polymerization. Specific examples of azo compounds include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitride), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], and 2,2'-azobis(N-butyl-2-methylpropionamide). Only one polymerization initiator may be used, or two or more may be used in combination. Furthermore, the polymerization initiator used in the first polymerization step and the polymerization initiator used in the second polymerization step may be the same or different.

[0072] The amount of polymerization initiator used is not particularly limited and can be set appropriately depending on the polymerization method employed. For example, in the case of the RAFT method, from the viewpoint of obtaining a polymer with a narrower molecular weight distribution, it is preferable to use 0.5 mol or less of polymerization initiator per 1 mol of RAFT agent, and more preferably 0.4 mol or less. Furthermore, from the viewpoint of carrying out the polymerization reaction stably, the lower limit of the amount of polymerization initiator used is preferably 0.01 mol or more, and more preferably 0.05 mol or more, per 1 mol of RAFT agent. The amount of polymerization initiator used per 1 mol of RAFT agent is preferably 0.01 to 0.5 mol, and more preferably 0.05 to 0.4 mol.

[0073] In the case of the RAFT method, the polymerization reaction may be carried out in the presence of a chain transfer agent, such as an alkylthiol compound having 2 to 20 carbon atoms, if necessary. Additionally, a dehydrating agent such as trimethyl orthoacetate or triethyl orthoacetate may be added to the reaction system if necessary.

[0074] The polymerization method of living radical polymerization is not particularly limited, and various methods such as solution polymerization, emulsion polymerization, miniemulsion polymerization, suspension polymerization, and bulk polymerization can be appropriately employed. For example, when solution polymerization is employed, the polymerization reaction is carried out using a known polymerization solvent. Various solvents can be used as polymerization solvents, such as saturated hydrocarbon compounds, aromatic compounds, ester compounds, ketone compounds, alcohol compounds, ether compounds, nitrile compounds, and water. It is preferable to use a solvent capable of dissolving monomers as the polymerization solvent, and more preferable to use an organic solvent capable of dissolving monomers. One polymerization solvent may be used alone, or two or more may be used in combination.

[0075] Specific examples of polymerization solvents include saturated hydrocarbon compounds such as hexane, heptane, and cyclohexane; aromatic compounds such as benzene, toluene, xylene, and anisole; ester compounds such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl formate, and methyl propionate; ketone compounds such as acetone, methyl ethyl ketone, and cyclohexanone; alcohol compounds such as methanol, ethanol, and 2-propanol; ether compounds such as tetrahydrofuran; and nitrile compounds such as acetonitrile. Other polymerization solvents such as dimethylformamide, dimethyl sulfoxide, and water may also be used. It is preferable to use a solvent capable of dissolving monomers as the polymerization solvent.

[0076] The amount of polymerization solvent used is preferably 5 to 200 parts by mass, and more preferably 10 to 100 parts by mass, relative to 100 parts by mass of the total amount of monomers used in the polymerization reaction. Using 100 parts by mass or less of polymerization solvent is preferable because it allows for a high polymerization rate in a short time. Using 10 parts by mass or more of polymerization solvent is preferable because it allows for efficient removal of polymerization heat and suppression of the rise in reaction temperature.

[0077] The method of preparing each raw material may be a batch-type initial batch preparation in which all raw materials are prepared at once, a semi-continuous preparation in which at least some of the raw materials are continuously supplied to the reactor, or a continuous polymerization method in which all raw materials are continuously supplied and the product is continuously withdrawn from the reactor at the same time. For example, one of polymer block (A) and polymer block (B) may be polymerized using a batch-type initial batch preparation method, while the other may be polymerized using a semi-continuous preparation method or a continuous polymerization method.

[0078] The reaction temperature and reaction time in the polymerization reaction can be appropriately set depending on the type of polymerization method employed, as well as the type of monomer and polymerization solvent used. For example, in the case of the RAFT method, the reaction temperature is preferably 40°C to 100°C, more preferably 45°C to 90°C, and even more preferably 50°C to 80°C. A reaction temperature of 40°C or higher is preferable because it allows the polymerization reaction to proceed smoothly, and a reaction temperature of 100°C or lower is preferable because it suppresses side reactions and relaxes the restrictions on the initiators and polymerization solvents that can be used. The reaction time is preferably, for example, 1 hour to 48 hours, and more preferably 2 hours to 24 hours.

[0079] The polymerization described above yields a polymer-containing solution containing a vinyl polymer. The polymer-containing solution obtained by polymerization may be subjected to a known desolvation treatment to isolate and / or purify the vinyl polymer. Alternatively, the polymer may be isolated and / or purified after carrying out the following reaction steps as needed. The treatment for isolating and purifying the polymer can be carried out according to known methods.

[0080] If the vinyl polymer obtained by the above polymerization has a thiocarbonylthio group derived from the RAFT agent, a step of reacting the vinyl polymer with a nucleophile (hereinafter also referred to as the "post-treatment step") may be performed. It is presumed that by reacting the thiocarbonylthio group of the vinyl polymer with a nucleophile, the thiocarbonylthio group is converted to a thiol group, and that this thiol group reacts with unreacted monomers remaining in the polymerization system (for example, acrylate compounds in the reaction system) (Michael addition reaction), thereby obtaining a vinyl polymer from which the thiocarbonylthio group has been removed.

[0081] Examples of nucleophiles include ammonia compounds, primary and / or secondary amine compounds, alkali metal alkoxides, hydroxides, and thiols. Of these, primary and / or secondary amine compounds are preferably used as nucleophiles due to their reactivity.

[0082] The amount of nucleophile used is preferably such that the molar equivalent of the nucleophile relative to the thiocarbonylthio group is 2 to 90 mol equivalents. From the viewpoint of reaction efficiency, the amount of nucleophile used is preferably 2.5 mol equivalents or more, more preferably 3 mol equivalents or more, and even more preferably 3.5 mol equivalents or more, relative to the thiocarbonylthio group. Furthermore, in order to reduce the influence of odor from unreacted nucleophile, the amount of nucleophile used is preferably 75 mol equivalents or less, more preferably 60 mol equivalents or less, and even more preferably 50 mol equivalents or less, relative to the thiocarbonylthio group.

[0083] For the reaction between the thiocarbonylthio group and the nucleophile, known reactors such as batch reactors and tubular reactors can be used. The reaction temperature is preferably 10°C or higher, more preferably 15°C or higher, and even more preferably 25°C or higher, in order to increase the reaction efficiency. Furthermore, to minimize the occurrence of side reactions (e.g., nucleophilic reactions to the polymer main chain), the reaction temperature is preferably 80°C or lower, more preferably 60°C or lower, and even more preferably 50°C or lower. The reaction pressure is usually at atmospheric pressure, but may be increased or decreased as needed. The reaction time is preferably 1 hour or more, and more preferably 2 hours or more, in terms of reaction efficiency. Furthermore, the upper limit of the reaction time is preferably 48 hours or less, and more preferably 24 hours or less, in order to suppress side reactions such as nucleophilic reactions to the polymer main chain. When a polymer solution is obtained by the above reaction, the polymer can be isolated by performing a known desolvation treatment on this polymer solution.

[0084] Here, in a crosslinked structure formed by a vinyl block copolymer having hydroxyl groups as crosslinkable functional groups, if the distance between crosslinking points of the vinyl block copolymer is long and the crosslinked structure is uniform, the crosslinked product (i.e., cured product) is thought to be able to exhibit sufficient elasticity and also be able to adequately distribute stress. In this respect, it is thought that the vinyl copolymer (P) was able to form a cured product with a sufficiently long distance between crosslinking points of the polymer and a uniform crosslinked structure. As a result, it is thought that the cured product obtained by curing a curable resin composition containing the vinyl copolymer (P) has good tensile properties and can exhibit sufficient weather resistance and heat resistance to withstand the dynamic deformation of the cured product itself caused by temperature, humidity, etc.

[0085] Curable Resin Compositions Vinyl copolymers (P) are suitable for applications such as sealants, adhesives, coatings, and paints due to their high tensile strength, heat resistance, and weather resistance. Vinyl copolymers (P) are preferably compounded with polyfunctional isocyanate compounds and applied to applications such as sealants, adhesives, coatings, and paints. Furthermore, curable resin compositions containing vinyl copolymers (P) and polyfunctional isocyanate compounds can be molded and subjected to heat treatment or other treatments as needed to obtain cured products suitable for various applications.

[0086] (Polyfunctional isocyanate compounds) Polyfunctional isocyanate compounds are not particularly limited, as long as they are compounds having two or more isocyanate groups. Polyfunctional isocyanate compounds can function as crosslinking agents.

[0087] As polyfunctional isocyanate compounds, various aromatic, aliphatic, and alicyclic polyfunctional isocyanate compounds, as well as modified products (prepolymers, etc.) of these polyfunctional isocyanate compounds can be used. Specifically, aromatic isocyanate compounds such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), and tollidine diisocyanate (TODI); hexamethylene diisocyanate (HDI), and lysine diisocyanate (L Examples include aliphatic isocyanate compounds such as DI; alicyclic isocyanate compounds such as isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), and hydrogenated MDI (H12MDI); and modified isocyanate compounds such as urethane modified, dimer, trimer, carbodiimide modified, urea modified, isocyanurate modified, oxazolidone modified, and isocyanate group-terminated prepolymers.

[0088] In the curable resin composition of this disclosure, the content of the polyfunctional isocyanate compound is preferably 0.1 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the total vinyl copolymer (P). More preferably, the content of the polyfunctional isocyanate compound is 0.5 parts by mass or more and 15 parts by mass or less, and even more preferably 1 part by mass or more and 10 parts by mass or less.

[0089] (Other components) In addition to the vinyl copolymer (P) and the polyfunctional isocyanate compound, the curable resin composition of this disclosure may contain various components such as known additives as needed. Examples of such additives include curing catalysts (also called curing accelerators), plasticizers, fillers, pigments, adhesion promoters, dehydrating agents, antioxidants, and ultraviolet absorbers.

[0090] As curing catalysts (curing accelerators), known compounds such as tin-based catalysts, titanium-based catalysts, and tertiary amines can be used. Among these, examples of tin-based catalysts include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetonate, and dioctyltin dilaurate. Specifically, examples include Nitto Chemical Co., Ltd.'s product names "Neostan U-28," "Neostan U-100," "Neostan U-200," "Neostan U-220H," "Neostan U-303," "Neostan U-810," and "SCAT-24."

[0091] Examples of titanium-based catalysts include tetraisopropyl titanate, tetra-n-butyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetylacetonate, dibutoxytitanium diacetylacetonate, diisopropoxytitanium diacetylacetonate, titanium octylene glycolate, and titanium lactate.

[0092] Examples of tertiary amines include triethylamine, tributylamine, triethylenediamine, hexamethylenetetramine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), diazabicyclononene (DBN), N-methylmorpholine, and N-ethylmorpholine.

[0093] The amount of curing catalyst added is preferably 0.01 to 5 parts by mass, and more preferably 0.02 to 2 parts by mass, based on 100 parts by mass of the total amount of vinyl copolymer (P).

[0094] Examples of plasticizers include liquid polyurethane resins; phthalate esters such as dibutyl phthalate, diheptyl phthalate, di(2-ethylhexyl) phthalate, diisodecyl phthalate, and butyl benzyl phthalate; non-aromatic dibasic acid esters such as dioctyl adipate, dioctyl sebacate, dibutyl sebacate, and isodecyl succinate; aliphatic esters such as butyl oleate and methyl acetylricinoleate; phosphate esters such as tricresyl phosphate and tributyl phosphate; trimellitic acid esters; epoxidized unsaturated oils and fats, epoxidized unsaturated fatty acid esters, and alicyclic epoxy compounds. Examples include epoxy plasticizers such as epichlorohydrin derivatives and mixtures thereof; polyester plasticizers obtained from dicarboxylic acids and diols; etherified or esterified polyalkylene glycols such as polyethylene glycol and polypropylene glycol; polyether plasticizers such as sugar-based polyethers obtained by addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide to sugar polyhydric alcohols such as sucrose, followed by etherification or esterification; polystyrene plasticizers such as poly-α-methylstyrene; and poly(meth)acrylates without crosslinking functional groups. Of these, poly(meth)acrylates without crosslinking functional groups are preferred in terms of durability such as weather resistance of the cured product. Among the plasticizers, polymers with an Mw in the range of 1,000 to 7,000 and a glass transition temperature of -30°C or lower are preferred.

[0095] The amount of plasticizer used is preferably in the range of 0 to 100 parts by mass, but may also be in the range of 0 to 90 parts by mass, or 0 to 80 parts by mass, based on 100 parts by mass of the total amount of vinyl copolymer (P).

[0096] Examples of fillers include light calcium carbonate with an average particle size of approximately 0.02 to 2.0 μm, heavy calcium carbonate with an average particle size of approximately 1.0 to 5.0 μm, titanium dioxide, carbon black, synthetic silica, talc, zeolite, mica, silica, calcined clay, kaolin, bentonite, aluminum hydroxide, barium sulfate, glass balloons, silica balloons, and polymethyl methacrylate balloons. These fillers improve the mechanical properties of the cured product formed by the curable resin composition, thereby improving the tensile strength and tensile elongation of the cured product.

[0097] Among these, light calcium carbonate, heavy calcium carbonate, and titanium dioxide are preferred as fillers due to their high effect in improving physical properties, and a mixture of light calcium carbonate and heavy calcium carbonate is more preferred. The amount of filler to be blended is preferably 20 to 300 parts by mass, and more preferably 50 to 200 parts by mass, per 100 parts by mass of the total amount of vinyl copolymer (P) and polyoxyalkylene polymer. When a mixture of light calcium carbonate and heavy calcium carbonate is used, the ratio of light calcium carbonate to heavy calcium carbonate is preferably in the range of 90 / 10 to 50 / 50 by mass. Titanium dioxide, carbon black, etc. may also be blended into the curable resin composition as a pigment.

[0098] Examples of adhesion-improving agents include aminosilanes such as "KBM602," "KBM603," "KBE602," "KBE603," "KBM902," and "KBM903" manufactured by Shin-Etsu Silicone Co., Ltd., and "SH6020" manufactured by Toray Dow Corning Co., Ltd. Examples of dehydrating agents include methyl orthoformate, methyl orthoacetate, and vinylsilane.

[0099] As anti-aging agents, ultraviolet absorbers such as benzophenone compounds, benzotriazole compounds, and oxalic acid anilide compounds, light stabilizers such as hindered amine compounds, antioxidants such as hindered phenol compounds, heat stabilizers, and mixtures thereof can be used.

[0100] Examples of UV absorbers include BASF's "Chinubin 571," "Chinubin 1130," and "Chinubin 327." Examples of light stabilizers include BASF's "Chinubin 292," "Chinubin 144," and "Chinubin 123," and Sankyo's "Sanol 770." Examples of heat stabilizers include BASF's "Irganox 1135," "Irganox 1520," and "Irganox 1330." Alternatively, BASF's "Chinubin B75," a mixture of UV absorber, light stabilizer, and heat stabilizer, may be used.

[0101] Other components to be added to the curable resin composition include, in addition to the above, oils, crosslinking agents other than polyfunctional isocyanate compounds, and crosslinkable group-containing polymers different from vinyl copolymers (P).

[0102] To adjust the performance, coating properties, processability, etc., of a curable resin composition containing a vinyl copolymer (P), thermoplastic resins may be added to the curable resin composition as other components. Specific examples of thermoplastic resins include polyolefin resins such as polyethylene and polypropylene, styrene resins such as polystyrene, vinyl resins such as polyvinyl chloride, polyester resins, and polyamide resins. Known elastomers may also be added.

[0103] The curable resin composition of this disclosure can be prepared as a one-component curable resin composition, in which all components are pre-mixed and sealed for storage, and the composition hardens by absorbing moisture from the air after application. Alternatively, it can be prepared as a two-component curable resin composition in which components such as a curing catalyst, filler, plasticizer, and water are separately mixed as a curing agent, and the curing agent and resin composition are mixed before use. Of these, the one-component type is more preferred because it is easier to handle and reduces the likelihood of mixing errors during application.

[0104] Curable resin compositions containing vinyl copolymers (P) exhibit good fluidity in a temperature range of approximately 25°C to 150°C. Therefore, they can be applied to various coating applications as well as molding processes using various methods such as extrusion molding, injection molding, and casting.

[0105] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the following, "parts" and "%" mean "parts by mass" and "mass%", respectively, unless otherwise specified. Details of the analytical methods for the polymers obtained in the synthesis example, production example, and comparative production example are as follows.

[0106] ≪Method for Polymer Analysis≫ <Molecular Weight Measurement> Using a gel permeation chromatograph (model "HLC-8320", manufactured by Tosoh Corporation), the weight-average molecular weight (Mw) and number-average molecular weight (Mn) in polystyrene equivalent were obtained under the following conditions. The molecular weight distribution (Mw / Mn) was also calculated from the obtained values. ○Measurement conditions Column: 4 x TSKgel SuperMultiporeHZ-M (manufactured by Tosoh Corporation) Column temperature: 40°C Eluent: Tetrahydrofuran Detector: RI

[0107] <Viscosity Measurement> The E-type viscosity was measured using a TVE-20H viscometer (cone / flat plate type, manufactured by Toki Sangyo Co., Ltd.) under the following conditions. ○Measurement conditions Cone shape: Angle 1°34′, radius 24 mm (less than 10 Pa·s) Angle 3°, radius 7.7 mm (10 Pa·s or more) Temperature: 25℃±0.5℃

[0108] <Measurement of Non-Volatile Content Concentration of Polymerization Solution> Approximately 0.5 g of the sample was placed in a weighing bottle whose weight had been measured in advance [Weighing bottle weight = W2 (unit: g)]. The weighing bottle and the sample were then accurately weighed together [Weight of sample and weighing bottle before drying = W0 (unit: g)]. The sample and weighing bottle were then placed in a hot air circulating dryer and dried at 155°C for 45 minutes. The weight of the weighing bottle after drying was measured [Weight of sample and weighing bottle after drying = W1 (unit: g)]. The mass of non-volatile content in the sample [X (unit: g)] was then calculated using the following formula (2): X = (W1 - W2) / (W0 - W2) ... (2)

[0109] <Average number of hydroxyl groups per molecule of vinyl copolymer> The average number of hydroxyl groups per molecule of vinyl copolymer (hereinafter also referred to as "f(OH)") was calculated using the following formula (3) from the amount (parts by mass) of hydroxyl group-containing monomer units when the total amount of monomer units constituting the vinyl copolymer is set to 100 parts by mass. The amount (parts by mass) of hydroxyl group-containing monomer units was determined by gas chromatography (GC) measurement. f(OH) = {Amount of hydroxyl group-containing monomer units / (Molecular weight of hydroxyl group-containing monomer × 100 / Mn)} ... (3)

[0110] <Gas Chromatography (GC) Measurement> ○Measurement Conditions Column: Capillary columns Agilent CP-Wax52CB (60m x 0.32mm ID, df = 0.5μm) and Agilent DB-1 (30m x 0.32mm ID, df = 1.0μm) Solvent: Tetrahydrofuran column Temperature: 50°C (5 min), 7°C / min, 230°C (5 min)

[0111] <Hydrogen Value of Vinyl Copolymers> The hydroxyl value of vinyl copolymers was measured by potentiometric titration in accordance with "7. Hydroxyl Value" of JIS K 0070 (1992). The details of the measurement method are as follows: [Measurement Procedure] (1) 4.2 g of acetic anhydride was taken into a 100 mL volumetric flask, and pyridine was added to make a total volume of 100 mL. The mixture was shaken well and homogeneous dissolution was achieved. (2) 0.5 g of the sample (vinyl copolymer) was accurately weighed into a test tube. (3) 5 mL of the acetic anhydride / pyridine solution prepared in (1) was added to the test tube from (2) using a volumetric pipette. (4) A stirring bar was placed in the test tube, and then the test tube was capped with a metal cap. The test tube was heated at 95°C for 2 hours while stirring the contents (acetylation reaction). If the sample was not dissolved at this time, a small amount of pyridine was added to dissolve it. (5) After adding 1 mL of pure water to the test tube, it was heated at 95°C for a further 10 minutes (hydrolysis of acetic anhydride). Then it was allowed to cool at room temperature. (6) The liquid in the test tube was transferred to a 100 mL polypropylene cup. At that time, any liquid remaining on the inner wall of the test tube was rinsed with THF (50 mL). (7) The liquid obtained in (6) was stirred at room temperature for 10 minutes to make it homogenized to obtain the test solution. The test solution was titrated by measuring the potentiometric difference under the following conditions, and the inflection point of the titration curve was taken as the endpoint. In addition, a blank solution prepared in advance (a solution treated in (3) to (6) without adding a vinyl copolymer) was titrated in the same manner. Potentiometric titrator: HIRANUMA's "COM-A19" automatic titrator Burette head: H-3000 Tight station: TS-3000 Stirrer: K-3000T Potentiometric titration measurement unit: S-3000 Titrate: 0.1 mol / L-KOH / EtOH solution (8) The hydroxyl value (mgKOH / g) was calculated using the following formula: Hydroxyl value = {0.1 × F × (B - C) × 56.1} / W + A F: Factor of the 0.1 mol / L-KOH / EtOH solution B: Volume of the 0.1 mol / L-KOH / EtOH solution used as the blank (mL) C: Volume of the 0.1 mol / L-KOH / EtOH solution used as the test solution (mL) W: Mass of the sample (g) A: Acid value of the sample (mgKOH / g)

[0112] <SP value of vinyl copolymer> The SP value is calculated using the Fedors method (unit: [cal / cm²]) ３ ] １／２ Specifically, the SP values ​​of the polymers were calculated using the calculation method described in "Polymer Engineering and Science" 14(2), 147 (1974) by R. F. Fedors.

[0113] <Measurement of Glass Transition Temperature (Tg)> The Tg of vinyl copolymers was measured using a differential scanning calorimeter (DSC) under the following conditions: DSC: NETZSCH DSC 214 Polyma; Heating temperature: 10°C / min; Measurement atmosphere: Nitrogen

[0114] ≪Production and Evaluation of Vinyl Block Copolymers≫ <Production of Polymer Block (A)> [Synthesis Example 1] Production of Polymer a-1 In a 1 L flask equipped with a stirrer and thermometer, 7.3 parts of S,S-dibenzyltrithiocarbonate (hereinafter also referred to as "DBTTC"), 0.19 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) (hereinafter also referred to as "V-65"), 55.5 parts of n-butyl acrylate (hereinafter also referred to as "BA"), 33.0 parts of 2-ethylhexyl acrylate (hereinafter also referred to as "HA"), 11.5 parts of 2-hydroxyethyl acrylate (hereinafter also referred to as "HEA"), and 100.0 parts of ethyl acetate were charged. The mixture was thoroughly degassed by nitrogen bubbling, and the temperature was raised to 58°C to start polymerization. Two hours after the start of polymerization, the temperature was raised to 78°C over one hour, and the reaction was continued at 78°C for another two hours. Subsequently, the reaction was stopped by cooling to room temperature, and a solution containing polymer a-1 was obtained. The molecular weight of the obtained polymer a-1 was measured by gel permeation chromatography (GPC) (polystyrene equivalent), and the results were Mn 3,790, Mw 4,580, and Mw / Mn 1.21. The reaction rates of each monomer, measured by gas chromatography (GC), were BA: 89%, HA: 89%, and HEA: 97%. The average number of hydroxyl groups per molecule of polymer a-1 was calculated to be 4.0. The non-volatile content concentration of the polymerization solution measured by the above method was 48.3%.

[0115] [Synthesis Examples 2-4] Polymers a-2 to a-4 were obtained by performing the same procedure as in Synthesis Example 1, except that the raw materials used for the production of polymers a-2 to a-4 were as shown in Table 1. The molecular weight of each polymer, the average number of hydroxyl groups per molecule, the non-volatile content concentration of the polymerization solution, and the reaction rate of each monomer were measured and are shown in Table 1. In Table 1, "initial charge monomer" refers to the monomer charged into the 1 L flask (reactor) before the start of polymerization, and "continuous supply monomer" refers to the monomer continuously supplied dropwise into the 1 L flask (reactor) over a period of 2 hours immediately after the start of polymerization. "initial charge initiator" refers to the initiator charged into the 1 L flask (reactor) before the start of polymerization, and "additional initiator" refers to the initiator added all at once into the 1 L flask (reactor) 2 hours after the start of polymerization.

[0116] [Synthesis Example 5] Preparation of Polymer a-5 In a 1 L flask equipped with a stirrer and thermometer, DBTTC (7.3 parts), 2,2'-azobis(2-methylbutyronitrile) (hereinafter also referred to as "ABN-E") (0.11 parts), BA (38.5 parts), methyl methacrylate (hereinafter also referred to as "MMA") (10.0 parts), HEA (11.5 parts), and ethyl acetate (45.0 parts) were charged. The mixture was thoroughly degassed by nitrogen bubbling, and the temperature was raised to 78°C to start polymerization. In the 1 L flask immediately after the start of polymerization, MMA (40.0 parts) was continuously added dropwise over 2 hours. Two hours after the start of polymerization, ABN-E (0.16 parts) was added all at once to the 1 L flask, and the reaction was continued for another 3 hours at 78°C. After that, the reaction was stopped by cooling to room temperature, and a solution containing polymer a-5 was obtained. The molecular weight of each polymer, the average number of hydroxyl groups per molecule, the non-volatile content of the polymerization solution, and the reaction rate of each monomer were measured and are shown in Table 1.

[0117]

[0118] The abbreviations for the compounds in Table 1 represent the following (the same applies to Tables 2-7): BA: n-butyl acrylate HA: 2-ethylhexyl acrylate TDA: n-tetradecyl acrylate MA: methyl acrylate MMA: methyl methacrylate HEA: 2-hydroxyethyl acrylate DBTTC: S,S-dibenzyl trithiocarbonate V-65: 2,2'-azobis(2,4-dimethylvaleronitrile) ABN-E: 2,2'-azobis(2-methylbutyronitrile)

[0119] <Production of Triblock Copolymer> [Synthesis Example 6] Production of Triblock Copolymer b-1 A 1 L flask equipped with a stirrer and thermometer was charged with a solution containing polymer a-1 obtained in Synthesis Example 1 (purity 48%, so 10.2 parts of polymer a-1 (21.3 parts × 0.48 = 10.2 parts)), BA (14.6 parts), HA (7.8 parts), ABN-E (0.064 parts) and ethyl acetate (30.0 parts). The mixture was thoroughly degassed by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70°C. In the 1 L flask after polymerization had started, BA (43.9 (1 part), HA (23.4 parts) were continuously added dropwise over 4 hours immediately after the start of polymerization. 4.5 hours after the start of polymerization, ABN-E (0.021 parts) was added all at once to a 1 L flask, and the reaction was continued for another 1.5 hours at 70°C. After that, the reaction was stopped by cooling to room temperature, and a solution containing triblock copolymer b-1 was obtained. Note that "purity" is a value expressed as the ratio of the total amount of monomer to the total amount of charge during polymerization (total amount of monomer, control agent, initiator, and solvent) (unit: %). The molecular weights of the obtained triblock copolymer b-1 were Mn 29,900, Mw 33,500, and Mw / Mn 1.12. The reaction rates of each monomer, as measured by gas chromatography (GC), were BA: 90%, HA: 91%, and HEA: 100%. The obtained triblock copolymer b-1 has a polymer block (A) consisting of BA / HA / HEA ≈ 55 / 33 / 12 (wt%) and a polymer block (B) consisting of BA / HA / HEA ≈ 65 / 35 / 0.04 (wt%, with BA and HA values ​​rounded to the first decimal place), and is a triblock copolymer (polymer block (A)-(B)-(A) with a block structure of (A)-(B)-(A).

[0120] [Synthesis Examples 7-13] The same procedure as in Synthesis Example 6 was followed, except that the starting materials for the production of triblock copolymers b-2 to b-8 were used as shown in Tables 2 and 3, to obtain triblock copolymers b-2 to b-8. The molecular weight of each polymer and the reaction rate of each monomer were measured and are shown in Tables 2 and 3. In Tables 2 and 3, "initial starting monomer" refers to the monomer that was charged into the 1 L flask (reactor) together with the polymer block (A) before the start of polymerization, "continuous supply monomer" refers to the monomer that was continuously supplied dropwise into the 1 L flask (reactor) immediately after the start of polymerization for the period indicated in "supply time" in Tables 2 and 3, and "additional monomer" refers to the monomer that was added all at once into the 1 L flask (reactor) 2 hours after the start of polymerization. Among the initiators, "0h addition" refers to the initiator added to the 1L flask (reactor) before polymerization began, "2h addition" refers to the initiator added all at once to the 1L flask (reactor) 2 hours after polymerization began, and "4.5h addition" refers to the initiator added all at once to the 1L flask (reactor) 4.5 hours after polymerization began.

[0121] [Synthesis Example 14] Production of Triblock Copolymer b-9 A 1 L flask equipped with a stirrer and thermometer was charged with a solution containing polymer a-1 obtained in Synthesis Example 1 (5.26 parts of polymer a-1 (11.0 parts × 0.48 = 5.26 parts) due to its purity of 48%), BA (12.9 parts), HA (8.3 parts), ABN-E (0.064 parts), and ethyl acetate (35.0 parts). The mixture was thoroughly degassed by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70°C. In the 1 L flask after polymerization had started, BA (38.8 parts) HA (24.8 parts) was continuously added dropwise from the start of polymerization for 1 hour and again from 3 to 5 hours. Two hours after the start of polymerization, isobornyl acrylate (hereinafter also referred to as "IBXA") (10.0 parts) and ABN-E (0.021 parts) were added all at once to a 1 L flask, and the reaction was continued for another 5 hours at 70°C. After that, the reaction was stopped by cooling to room temperature, and a solution containing triblock copolymer b-9 was obtained. The molecular weight of each polymer and the reaction rate of each monomer were measured and are shown in Table 3.

[0122] [Synthesis Examples 15 and 16] Production of Triblock Copolymers b-10 and b-11 The same procedure as in Synthesis Example 14 was carried out except that the additional monomer was changed to obtain Triblock copolymers b-10 and b-11. The molecular weight of each polymer and the reaction rate of each monomer were measured and are shown in Table 3.

[0123]

[0124]

[0125] In Tables 2 and 3, abbreviations other than those listed in Table 1 represent the following: IBXA: Isobornyl acrylate; TBAM: N-tert-butylacrylamide; DMAA: N,N-dimethylacrylamide

[0126] <Preparation of Pentablock Copolymer> [Synthesis Example 17] Preparation of Pentablock Copolymer c-1 A solution containing Triblock copolymer b-1 obtained in Synthesis Example 6 (97.34 parts), BA (1.00 part), HA (0.50 part), HEA (1.16 part), and ethyl acetate (3.0 part) were charged, and the mixture was thoroughly degassed by nitrogen bubbling and heated to 60°C. After the internal temperature stabilized at 60°C, ABN-E (0.037 parts) was added and polymerization was started. Two hours after the start of polymerization, the temperature was raised to 78°C over one hour, and the reaction was continued at 78°C for another three hours. Six hours after the start of polymerization, the reaction was stopped by cooling to room temperature, and a solution containing Pentablock copolymer c-1 was obtained. The molecular weight of Pentablock copolymer c-1 was Mn 29,800, Mw 35,300, and Mw / Mn 1.18. Furthermore, the reaction rates of each monomer measured by gas chromatography (GC) were BA: 90%, HA: 90%, and HEA: 100%. The obtained pentablock copolymer c-1 has polymer blocks (A) with a high ratio of HEA and polymer blocks (B) with a low ratio of HEA relative to the total monomer units constituting the block copolymer, and is a pentablock copolymer (polymer block (A) / polymer block (B) / polymer block (A) / polymer block (B) / polymer block (A)) having a block structure of (A)-(B)-(A)-(B)-(A). The composition ratio of polymer block (A) to polymer block (B) determined from the polymerization rate was (A) / (B) ≈ 19 / 81 (wt%).

[0127] [Synthesis Examples 18-27] Pentablock copolymers c-2 to c-11 were obtained by performing the same procedure as in Synthesis Example 17, except that the raw materials used for the production of pentablock copolymers c-2 to c-11 were as shown in Tables 4 and 5. The molecular weight of each polymer was measured and is shown in Tables 4 and 5. The composition ratio of polymer block (A) and polymer block (B) was also calculated and is shown in Tables 4 and 5.

[0128]

[0129]

[0130] <Post-treatment process for pentablock copolymer> [Production Example 1] Production of block copolymer d-1 A solution containing pentablock copolymer c-1 (100.0 parts) obtained in Synthesis Example 17 was thoroughly degassed by nitrogen bubbling, and then n-propylamine (hereinafter also referred to as "PAm") (0.40 parts) was charged, and the decomposition reaction of the thiocarbonyl group was started in a constant temperature bath at 40°C. After 5 hours, the reaction was stopped by cooling to room temperature, and a solution containing block copolymer d-1 was obtained. The solution containing block copolymer d-1 was reduced to 20 kPa, and volatile components (unreacted monomers, solvents, etc.) were continuously distilled off in a thin film evaporator maintained at 120°C, and the non-volatile component, block copolymer d-1, was recovered. Block copolymer d-1 is a triblock copolymer (polymer block (A) / polymer block (B) / polymer block (A)) having a block structure of (A)-(B)-(A), comprising polymer block (A) with a high ratio of HEA to the total monomer units constituting the block structure and polymer block (B) with a low ratio of HEA. It is a Michael adduct of a thiol formed by the decomposition of the thiocarbonylthio group of pentablock copolymer c-1 by an amine and the remaining acrylate compound contained in pentablock copolymer c-1. １¹H-NMR measurements confirmed that the hydrogen peak (4.8 ppm) attached to the carbon adjacent to the thiocarbonylthio group, observed in pentablock copolymer c-1, disappeared in block copolymer d-1, and peaks (3.3 ppm, 2.9 ppm) originating from the Michael adduct with the remaining acrylate compound (the terminal molecular structure represented by general formula (4) below) appeared. In general formula (4), R represents a group having a structure derived from the remaining acrylate compound. The molecular weight of block copolymer d-1 was Mn 19,300, Mw 22,300, and Mw / Mn = 1.16. The polymer composition calculated from the monomer charging ratio and the reaction rate of each monomer measured by gas chromatography (GC) was BA units: 63.6 mass%, HA units: 34.2 mass%, HEA units: 2.2 mass%. The average number of hydroxyl groups per molecule was calculated to be 3.6. The hydroxyl value of block copolymer d-1 was 10.5 mg KOH / g, the glass transition temperature was -55°C, and the E-type viscosity was 91 Pa·s.

[0131]

[0132] [Production Examples 2-11] Block copolymers d-2 to d-11 were obtained by performing the same procedure as in Production Example 1, except that the raw materials used were as shown in Table 6 and the desolvation temperature was adjusted as appropriate. The molecular weight, polymer composition, average number of hydroxyl groups per molecule, hydroxyl value, glass transition temperature, and viscosity of each polymer were measured and are shown in Table 6.

[0133] <<Production and Evaluation of Vinyl Random Copolymers>> [Comparative Production Example 1] In a 1 L flask equipped with a stirrer and thermometer, S,S-dibenzyltrithiocarbonate (DBTTC) (0.73 parts), ABN-E (0.10 parts), BA (19.1 parts), HA (10.2 parts), HEA (0.7 parts), and ethyl acetate (35.0 parts) were thoroughly degassed by nitrogen bubbling, and the temperature was raised to 70°C to start polymerization. In the 1 L flask immediately after the start of polymerization, BA (44.6 parts), HA (23.8 parts), and HEA (1.6 parts) were continuously added dropwise over 4 hours and 40 minutes from the start of polymerization. Three hours after the start of polymerization, ABN-E (0.03 parts) was added all at once to the 1 L flask, the temperature was raised to 78°C over 30 minutes, and the reaction was continued at 78°C for a further 2.5 hours. Subsequently, the reaction was stopped by cooling to room temperature, and a solution containing random copolymer P-1 was obtained. The molecular weight of the obtained random copolymer P-1 was measured by GPC (polystyrene equivalent) and found to be Mn 30,900, Mw 36,200, and Mw / Mn 1.17. The reaction rates of each monomer, measured by gas chromatography (GC), were BA: 90%, HA: 91%, and HEA: 97%. The non-volatile content of the polymerization solution measured by the above method was 74.5%. Next, the solution containing the obtained random copolymer P-1 (100.0 parts) was thoroughly degassed by nitrogen bubbling, and then PAm (0.80 parts) was charged, and the decomposition reaction of the thiocarbonyl group was started in a constant temperature bath at 40°C. After 5 hours, the reaction was stopped by cooling to room temperature, and a solution containing random copolymer R-1 was obtained. The solution containing random copolymer R-1 was reduced to 20 kPa, and volatile components (unreacted monomers, solvents, etc.) were continuously removed by distillation in a thin-film evaporator maintained at 120°C, recovering the non-volatile component, random copolymer R-1. The molecular weight, polymer composition, average number of hydroxyl groups per molecule, hydroxyl value, glass transition temperature, and viscosity of random copolymer R-1 were measured and are shown in Table 6.

[0134]

[0135] In Table 6, abbreviations other than those listed in Tables 1 and 2 represent the following: PAm: n-propylamine

[0136] [Comparative Manufacturing Example 2] The temperature of a 1000 mL pressurized stirred-tank reactor equipped with an oil jacket was maintained at 198°C. Then, while maintaining a constant reactor pressure, a monomer mixture consisting of BA (39.0 parts), HA (57.0 parts), HEA (4.0 parts), isopropyl alcohol (hereinafter also referred to as "IPA") (3.0 parts), trimethyl orthoacetate (hereinafter also referred to as "MOA") (3.0 parts), methyl ethyl ketone (hereinafter also referred to as "MEK") (4.0 parts), and di-t-hexyl peroxide (manufactured by NOF Corporation, trade name "Perhexyl D", hereinafter also referred to as "DTHP") (0.02 parts) was continuously supplied from the raw material tank to the reactor at a constant supply rate (48 g / min, residence time: 12 minutes), and a reaction solution equivalent to the amount of monomer mixture supplied was continuously withdrawn from the outlet. Immediately after the start of the reaction, the reaction temperature initially decreased, followed by a temperature increase due to polymerization heat. However, by controlling the temperature of the oil jacket, the reaction temperature was maintained at 198-199°C. The point at which the temperature stabilized after the start of supplying the monomer mixture was designated as the starting point for sampling the reaction solution. The reaction was continued for 25 minutes, resulting in the supply of 1.2 kg of monomer mixture and the recovery of 1.2 kg of reaction solution. The reaction solution was then introduced into a thin-film evaporator to separate volatile components such as unreacted monomers, yielding random copolymer R-2. The molecular weight, average number of hydroxyl groups per molecule, hydroxyl value, glass transition temperature, and viscosity of random copolymer R-2 were measured and are shown in Table 7.

[0137] [Comparative Production Examples 3-5] Random copolymers R-3 to R-5 were obtained by performing the same procedure as in Comparative Production Example 1, except that the raw materials used were as shown in Table 7 and the reaction temperature was adjusted as appropriate. The molecular weight, average number of hydroxyl groups per molecule, hydroxyl value, glass transition temperature, and viscosity of each polymer were measured and are shown in Table 7.

[0138]

[0139] In Table 7, abbreviations other than those listed in Table 1 represent the following: BMA: n-butyl methacrylate; HEMA: 2-hydroxyethyl methacrylate; IPA: isopropyl alcohol; MOA: trimethyl orthoacetate; MEK: methyl ethyl ketone; DTHP: di-tert-hexyl peroxide (manufactured by NOF Corporation, trade name "Perhexyl D"); DTBP: di-tert-butyl peroxide (manufactured by NOF Corporation, trade name "Perbutyl D")

[0140] <<Production and Evaluation of Curable Resin Compositions>> <Production of Curable Resin Compositions> [Example 1] Block copolymer d-1 obtained in Production Example 1 was used as the vinyl copolymer of the base resin, and each component was blended according to the blending ratios shown in Table 8, and a curable resin composition was prepared according to a conventional method.

[0141] [Examples 2-11, Comparative Examples 1-5] Using the vinyl copolymers obtained in Production Examples 2-11 and Comparative Production Examples 1-5, curable resin compositions were prepared by blending each component according to the blending ratios shown in Tables 8 and 9, and performing the same procedure as in Example 1.

[0142] [Comparative Example 6] PREMINOL S 4013F (hereinafter also referred to as "S 4013F") (manufactured by AGC, polyether polyol, 2 functional groups, hydroxyl value 9.6 mg KOH / g) was used, and the same procedure as in Example 1 was performed to prepare a curable resin composition.

[0143]

[0144]

[0145] Details of the compounds in Tables 8 and 9 are as follows: • Polyfunctional isocyanate compound: Coronate HX (manufactured by Tosoh Corporation) • Light calcium carbonate: Viscolite-EL20 (manufactured by Shiraishi Calcium Co., Ltd.) • Heavy calcium carbonate: Super SS (manufactured by Maruo Calcium Co., Ltd.) • Titanium dioxide: R-820 (manufactured by Ishihara Sangyo Co., Ltd.) • Curing catalyst: Tin catalyst, Neostan U-810 (manufactured by Ishihara Sangyo Co., Ltd.) MEK (methyl ethyl ketone) was used as the dilution solvent for the curing catalyst.

[0146] <Evaluation> The curable resin compositions prepared above were evaluated using the following method. The evaluation results are shown in Tables 8 and 9.

[0147] (Tensile Properties) Each curable resin composition was applied to a Teflon® sheet to a thickness of 1 mm at room temperature (25°C) and heated in a 50°C dryer for 15 minutes. Then, it was heated in a 120°C dryer for 10 minutes and cured for 1 day under conditions of 23°C and 50% RH (relative humidity). A dumbbell for tensile testing was prepared from the resulting cured sheet and measured using a tensile testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation). The shape of the dumbbell for tensile testing was based on the Japanese Industrial Standard JIS K 6251, type 3. Specifically, the strength at 50% elongation (M501, unit: MPa), breaking strength (Ts1, unit: MPa), and breaking elongation (El1, unit: %) were measured under conditions of a tensile speed of 200 mm / min in an environment of 23°C and 50% humidity. Furthermore, the tensile product (Tp1, in MPa·%) was calculated using the following formula (5): Tp1 [MPa·%) = Ts1 × El1 …(5) Tensile product (Tp １ A higher value of ) indicates superior tensile strength.

[0148] (Heat Resistance) The test dumbbells prepared in the tensile property evaluation described above were heated in a 100°C dryer for 7 days, and then cured for 1 day under conditions of 23°C and 50% RH (relative humidity). Subsequently, using a tensile testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation), the strength at 50% elongation (M502, unit: MPa), breaking strength (Ts2, unit: MPa), and breaking elongation (El2, unit: %) were measured under conditions of 23°C and 50% RH at a tensile speed of 200 mm / min. The tensile product (Tp2, unit: MPa・%) was also calculated using the following formula (6): Tp2 [MPa・%] = Ts2 × El2 … (6) A larger retention rate of breaking elongation (El2 / El1 × 100) and a larger value of tensile product (Tp2) indicate superior heat resistance.

[0149] (Bulk Weathering Resistance) The test dumbbells prepared in the tensile property evaluation described above were placed in a metering weather meter (DAIPLA METAL WEATHER KU-R5NCI-A, manufactured by DAIPLA Wintes Co., Ltd.) and accelerated weathering tests were conducted. The conditions were: irradiation at 63°C, 70% RH, and illuminance of 80 mW / cm². ２ The test was conducted by applying a shower for 2 minutes every 2 hours. After 150 hours, the specimens were tested using a tensile testing machine under conditions of 23°C and 50% RH, at a tensile speed of 200 mm / min, to measure the strength at 50% elongation (M503, unit: MPa), breaking strength (Ts3, unit: MPa), and breaking elongation (El3, unit: %). The tensile product (Tp3, unit: MPa・%) was also calculated using the following formula (7). Furthermore, the elongation retention rate (unit: %) was calculated when compared with the breaking elongation (El1, unit: %) of the tensile properties. Tp3 [MPa・%] = Ts3 × El3 … (7) The retention rate of breaking elongation (El3 / El1 × 100) is large, and the tensile product (Tp ３ A higher value indicates superior bulk weather resistance.

[0150] (Surface Weathering Resistance) The test dumbbells prepared in the tensile property evaluation described above were placed in a metering weather meter (DAIPLA METAL WEATHER KU-R5NCI-A, manufactured by DAIPLA Wintes Co., Ltd.) and accelerated weathering tests were conducted. The conditions were irradiation at 63°C, 70% RH, and illuminance of 80 mW / cm². ２ The test was conducted by applying a shower for 2 minutes every 2 hours. After 60 and 150 hours, the surface condition was visually inspected, and the weather resistance was evaluated based on the presence or absence of cracks and the degree of wrinkles and sagging on the surface, according to the following criteria: ○: No change in surface condition. △: Some cracks or wrinkles and sagging have occurred. ×: Cracks have occurred across the entire surface of the test piece.

[0151] <Results and Discussion> As is clear from the results of Examples 1 to 11, the cured products obtained from the curable resin composition containing vinyl block copolymers d-1 to d-11 exhibited excellent tensile properties, heat resistance, and weather resistance. It is presumed that the triblock copolymer ((A)-(B)-(A) triblock) having a block structure unit of polymer block (A) / polymer block (B) / polymer block (A) allowed for sufficient distance between crosslinking points, thereby enabling the acquisition of cured products with excellent tensile properties, heat resistance, and weather resistance.

[0152] On the other hand, Comparative Examples 1 to 5, which used vinyl random copolymers R-1 to R-5, exhibited inferior tensile properties, heat resistance, and weather resistance. In this regard, it is believed that vinyl random copolymer R-1 had a short distance between crosslinking points, resulting in reduced tensile properties, heat resistance, and weather resistance. Vinyl random copolymers R-2 to R-5 lacked the polymer block (A) / polymer block (B) / polymer block (A) block structure units, and also had a small number-average molecular weight of less than 10,000, further shortening the distance between crosslinking points. These factors likely contributed to a further decrease in tensile properties, heat resistance, and weather resistance. Comparative Example 6, which used the polyether polyol S4013F, showed fractures and numerous cracks in the test dumbbell when exposed to the heat resistance and weather resistance test environment for a predetermined time, making tensile testing impossible. From these results, it can be said that when polyether polyol is used as the base resin, sufficient heat resistance and weather resistance of the cured product cannot be ensured.

[0153] From the above, it can be said that a vinyl block copolymer having a block structure unit consisting of polymer block (A) / polymer block (B) / polymer block (A), not having polymer blocks with a Tg exceeding 0°C, having monomer units derived from hydroxyl group-containing vinyl monomers, and having a number average molecular weight (Mn) of 10,000 to 80,000 can be used to obtain a cured product with excellent tensile properties (tensile strength), heat resistance, and weather resistance. Furthermore, a curable resin composition containing such a vinyl block copolymer can be widely applied in various fields, such as coatings for automobile parts, electrical appliances, and medical-related products, packings, gaskets, or hose materials, as well as adhesive raw materials, civil engineering and construction materials, and daily necessities. Among these, it can be used more suitably in applications for civil engineering and construction materials, and among civil engineering and construction materials, it is particularly suitable for applications such as sealing materials and adhesives for exterior tiles.

[0154] The present invention is not limited to the embodiments described above, and encompasses various modifications and variations within the scope of equivalents, without departing from the spirit of the invention. Therefore, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of these elements, should be understood to fall within the scope and conceptual range of the present invention in light of the above teachings.

Claims

1. A vinyl block copolymer having hydroxyl groups, comprising block structural units consisting of polymer block (A) / polymer block (B) / polymer block (A), without polymer blocks having a glass transition temperature above 0°C, comprising monomer units derived from a hydroxyl group-containing vinyl monomer, and having a number average molecular weight (Mn) of 10,000 or more and 80,000 or less.

2. The vinyl block copolymer according to claim 1, wherein the hydroxyl value is 1.0 to 25.0 mgKOH / g.

3. The vinyl-based block copolymer according to claim 1, wherein the average number of hydroxyl groups per molecule is 1.8 or more.

4. The vinyl block copolymer according to claim 1, wherein the molecular weight distribution (Mw / Mn), expressed as the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), is 2.20 or less.

5. The vinyl block copolymer according to claim 1, wherein monomer units derived from an alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms in the ester portion are present in an amount of 50 to 99.5% by mass relative to the total amount of monomer units constituting the vinyl block copolymer.

6. The vinyl block copolymer according to claim 1, wherein the hydroxyl group-containing vinyl monomer is an alkyl (meth)acrylate having a hydroxyl group.

7. The vinyl block copolymer according to claim 1, wherein the content ratio of monomer units derived from the hydroxyl group-containing vinyl monomer is 4 to 30% by mass with respect to the total amount of monomer units constituting the polymer block (A).

8. The vinyl block copolymer according to claim 1, wherein the content ratio of monomer units derived from the hydroxyl group-containing vinyl monomer is less than 4% by mass relative to the total amount of monomer units constituting the polymer block (B).

9. The solubility parameter value (SP value) of the polymer block (A) is set to X [cal / cm²]. ３ ] １／２ The SP value of the polymer block (B) is Y [cal / cm²]. ３ ] １／２ In this case, X is 9.7 or more and 10.5 or less, and the ratio of X to Y (X / Y) is greater than 1.0 and 1.3 or less, according to claim 1.

10. The vinyl-based block copolymer according to claim 1, wherein the mass ratio of polymer block (A) to polymer block (B) is 1:100 to 50:50 when expressed as polymer block (A):polymer block (B).

11. A curable resin composition comprising a vinyl block copolymer according to any one of claims 1 to 10 and a polyfunctional isocyanate compound.

12. The curable resin composition according to claim 11, which is for use as a sealant, adhesive, tack, coating agent, or paint.

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