Vinyl polymer and curable resin composition

Abstract

A vinyl polymer having a crosslinkable functional group, the vinyl polymer having a viscosity at 25°C of 170 Pa·s or less and giving a cured object which has a degree of restoration of 80% or higher and an elongation at break of 150-500%.

Description

Vinyl polymers and curable resin compositions

[0001] [Cross-reference of related applications] This application claims priority under Japanese Patent Application No. 2024-221620, filed on 18 December 2024, which is incorporated herein by reference in its entirety. This disclosure relates to vinyl polymers and curable resin compositions.

[0002] Vinyl polymers having crosslinkable functional groups are widely known as curable resins used in industrial applications. These vinyl polymers, when combined with other components as needed, are widely used as curable resin compositions to produce various cured products such as paints, adhesives, sealants, molding materials, and rubber sheets.

[0003] As a vinyl polymer to be incorporated into a curable resin composition for producing cured products, Patent Document 1 discloses a vinyl polymer having crosslinkable silyl groups at both ends, obtained by living radical polymerization.

[0004] Japanese Patent Application Publication No. 11-130931

[0005] In recent years, with the improvement of the durability of buildings themselves, there has been a growing demand for high levels of workability, tensile strength, and weather resistance in sealants used in buildings. In particular, for applications where outdoor use is expected, such as in buildings, it is desirable that the cured product (especially the surface) 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 purpose is to provide a vinyl polymer that can yield a curable resin composition with excellent workability, as well as a cured product with excellent tensile properties 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 polymer having a crosslinkable functional group, having a viscosity within a specific range, and having physical properties of the cured vinyl polymer within a specific range, it is possible to obtain a curable resin composition with excellent workability, and moreover, a cured product with excellent tensile properties and weather resistance. Specifically, the present disclosure provides the following vinyl polymer and curable resin composition.

[0008] [1] A vinyl polymer having crosslinkable functional groups, wherein the viscosity of the vinyl polymer at 25°C is 170 Pa·s or less, the recovery rate of the cured product of the vinyl polymer is 80% or more, and the elongation at break is 150 to 500%. [2] The vinyl polymer according to [1], comprising: a vinyl polymer (I) having a weight-average molecular weight (Mw) of 30,000 to 100,000, a molecular weight distribution (Mw / Mn) of 1.8 or less, and an average number of crosslinkable functional groups per molecule of 1.8 or more; and a vinyl polymer (II) having a weight-average molecular weight (Mw) of 5,000 to 30,000, and an average number of crosslinkable functional groups per molecule of 0.2 to 0.9. [3] The vinyl polymer according to [2], wherein the vinyl polymer (I) is a block copolymer. [4] The vinyl polymer according to [2] or [3], wherein the vinyl polymer (I) contains 0.1 to 50% by mass of structural units derived from (meth)acrylate alkyl ester having an alkyl group with 10 or more carbon atoms in the ester portion, relative to the total structural units constituting the vinyl polymer (I). [5] The vinyl polymer according to any of [2] to [4], wherein the proportion of structural units derived from (meth)acrylate alkyl ester having an alkyl group with 2 or fewer carbon atoms in the ester portion is 20% by mass or less, relative to the total structural units constituting the vinyl polymer (I). [6] The vinyl polymer according to any of [2] to [5], wherein the proportion of structural units derived from (meth)acrylate alkyl ester having an alkyl group with 8 or more carbon atoms in the ester portion is 50% by mass or less, relative to the total structural units constituting the vinyl polymer (II). [7] The vinyl polymer according to any of [2] to [6], wherein the vinyl polymer (I) is a block copolymer consisting of polymer block (A) / polymer block (B) / polymer block (A). [8] The vinyl polymer of [7] wherein the polymer block (A) has the crosslinkable functional group. [9] The vinyl polymer of any of [2] to [8] wherein the vinyl polymer (II) is a random copolymer.

[10] The vinyl polymer of any of [2] to [6] wherein the vinyl polymer (I) is a block copolymer and the vinyl polymer (II) is a random copolymer.

[11] A vinyl polymer from any of [2] to

[10] , wherein the mass ratio of vinyl polymer (I) to vinyl polymer (II) is 50 / 50 to 90 / 10 when expressed as vinyl polymer (I) / vinyl polymer (II).

[12] A curable resin composition containing a vinyl polymer from any of [1] to

[11] and an oxyalkylene polymer having a crosslinkable silyl group.

[13] The curable resin composition of

[12] , wherein the mass ratio of vinyl polymer to oxyalkylene polymer is 10 / 90 to 90 / 10 when expressed as vinyl polymer / oxyalkylene polymer.

[14] The curable resin composition of

[12] or

[13] for use as a sealant, adhesive, tack, or paint.

[0009] The vinyl polymers of this disclosure can be used to obtain curable resin compositions with excellent workability. Furthermore, the vinyl polymers of this disclosure can be used to obtain cured products with excellent tensile properties and weather resistance.

[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 Polymers>> The vinyl polymers of this disclosure (hereinafter also referred to as "vinyl polymers (P)") are molecular assemblies containing polymers having crosslinkable functional groups, and have the following properties: The viscosity of vinyl polymers (P) at 25°C is 170 Pa·s or less. <ii> The recovery rate of the cured vinyl polymers (P) is 80% or more, and the elongation at break is 150-500%.

[0012] (Crosslinkable Functional Groups) Examples of crosslinkable functional groups include crosslinkable silyl groups, silanol groups, carboxyl groups, hydroxyl groups, epoxy groups, oxazoline groups, isocyanate groups, and polymerizable unsaturated groups. Of these, crosslinkable silyl groups are preferred among the crosslinkable functional groups of vinyl polymers because they can provide superior elongation and tensile strength at break of cured products obtained using vinyl polymers (P), and because their reactivity is easily controllable.

[0013] Examples of crosslinkable silyl groups include alkoxysilyl groups and halogenosilyl groups. Specific examples include trimethoxysilyl groups, triethoxysilyl groups, triisopropoxysilyl groups, tris(2-propenyloxy)silyl groups, methyldimethoxysilyl groups, diethoxymethylsilyl groups, ethyldiethoxysilyl groups, diisopropoxymethylsilyl groups, (chloromethyl)dimethoxysilyl groups, and (ethoxymethyl)dimethoxysilyl groups. Of these, alkoxysilyl groups are preferred because they exhibit good reactivity while maintaining high storage stability.

[0014] Furthermore, a crosslinkable silyl group can be considered as a single reaction site. Therefore, in this specification, the entire crosslinkable silyl group is considered as a single crosslinkable functional group. For example, vinyltrimethoxysilane is a vinyl monomer having a trimethoxysilyl group as a crosslinkable functional group, and the number of crosslinkable functional groups in one molecule is one. Similarly, vinylmethyldimethoxysilane is a vinyl monomer having a methyldimethoxysilyl group as a crosslinkable functional group, and the number of crosslinkable functional groups in one molecule is one.

[0015] (Viscosity of Vinyl Polymer) The vinyl polymer (P) has a viscosity at 25°C of 170 Pa·s or less. When the viscosity of the vinyl polymer exceeds 170 Pa·s, the fluidity of the vinyl polymer is insufficient, and the workability of the curable resin composition prepared using the vinyl polymer is poor. From the viewpoint of obtaining a curable resin composition with excellent workability, the viscosity of the vinyl polymer (P) at 25°C is preferably 165 Pa·s or less, more preferably 160 Pa·s or less, still more preferably 150 Pa·s or less, and particularly preferably 145 Pa·s or less. The lower limit of the viscosity of the vinyl polymer (P) is not particularly limited, but from the viewpoint of sufficiently increasing the mechanical strength of the cured product obtained using the vinyl polymer (P), it is more preferably 60 Pa·s or more, still more preferably 70 Pa·s or more, even more preferably 80 Pa·s or more, and still more preferably 90 Pa·s or more. In this specification, the viscosity of the vinyl polymer is the value measured at 25°C using an E-type viscometer. Details of the measurement method follow the method described in the examples below.

[0016] (Recovery Rate of Cured Product) The vinyl polymer (P) has a cured product recovery rate of 80% or more for the cured product obtained by curing the polymer. Here, the recovery rate of the cured product of the vinyl polymer refers to the ratio of the strain recovered after removing the load to the strain when a load is applied to the cured product of the vinyl polymer for a certain period of time to extend the cured product. That is, the vinyl polymer (P) can extend the cured product by applying a load for a certain period of time, and by observing at least partial recovery behavior of the strain of the cured product after removing the load applied to the cured product, the recovery rate of the cured product of the vinyl polymer can be determined. Specifically, let the distance between the gauge marks before elongation [mm] be L ０ and the distance between the gauge marks during elongation [mm] when extended by applying a load for a certain period of time be L １ and the distance between the gauge marks [mm] after removing the load be L ２ . In this case, the recovery rate of the cured product (unit: %) is represented by the following formula (1). Recovery rate [%] = (L １ - L ２ ) / (L １ - L ０ ) × 100... (1)

[0017] The recovery rate expressed by the above formula (1) can be used as an indicator of the rubber elasticity of the vinyl polymer. That is, the greater the recovery rate of the cured vinyl polymer, the higher the rubber elasticity of the vinyl polymer can be considered to be. The recovery rate of the cured vinyl polymer can be adjusted to a desired range by controlling the average number of crosslinkable functional groups per molecule of the vinyl polymer, the type of crosslinkable functional group, and the position in which the crosslinkable functional group is introduced. Furthermore, when the vinyl polymer is a blend containing two or more polymers, the recovery rate of the cured vinyl polymer can also be adjusted to a desired range by adjusting the blend ratio of the polymers. Details of the method for measuring the recovery rate of the cured product will follow the method described in the examples below.

[0018] If the recovery rate of the cured vinyl polymer is less than 80% as expressed by the above formula (1), the weather resistance of the cured product obtained using a curable resin composition containing the vinyl polymer will be insufficient. If the recovery rate of the cured vinyl polymer (P) is 80% or more, even if the cured product repeatedly expands and contracts due to external environmental changes such as temperature and humidity, the occurrence of cracks and wrinkles in the cured product due to such expansion and contraction can be effectively suppressed. There is no particular upper limit to the recovery rate of the vinyl polymer (P), but it is a value of 100% or less.

[0019] (Elongation at Breaking of Cured Material) For vinyl polymers (P), the elongation at breaking of the cured material obtained by curing the polymer is 150 to 500%. If the elongation at breaking of a cured vinyl polymer is less than 150%, the cured material will have poor flexibility. For example, when a vinyl polymer is applied as a sealant for exterior wall materials, the cured material (sealant) may not be able to follow the expansion and contraction of the exterior wall material (more specifically, changes in joint width) due to vibration, temperature, humidity, etc., resulting in the cured material being prone to cracks and wrinkles. On the other hand, if the elongation at breaking of a cured vinyl polymer exceeds 500%, the strength of the cured material tends to decrease.

[0020] From the perspective of improving the weather resistance and strength of the cured product in a well-balanced manner, the elongation at break of the cured product of the vinyl polymer (P) is preferably 160% or more, more preferably 170% or more. Also, the elongation at break of the cured product of the vinyl polymer (P) is preferably 480% or less, more preferably 450% or less, and still more preferably 440% or less. The elongation at break of the cured product is a value measured in accordance with JIS K 6251:2017. Details of the measurement method follow the method described in the examples below. Note that for a cured product obtained by curing a vinyl polymer, if the crosslinked structure of the vinyl polymer is non-uniform or there are uncrosslinked portions due to, for example, too few crosslinkable functional groups in the vinyl polymer, it may not be possible to calculate the elongation at break of the cured product of the vinyl polymer.

[0021] The preferable range of the elongation at break in the cured product of the vinyl polymer (P) can be set by appropriately combining the aforementioned upper and lower limits. Specifically, the elongation at break of the cured product is preferably 150 - 480%, more preferably 160 - 450%, and still more preferably 170 - 440%.

[0022] The elongation at break of the cured product of the vinyl polymer can also be adjusted to a desired range by controlling the average number of crosslinkable functional groups per molecule of the vinyl polymer, the type of crosslinkable functional group, and the introduction position of the crosslinkable functional group. Also, when the vinyl polymer is in the form of a blend containing two or more polymers, the elongation at break of the cured product of the vinyl polymer can be adjusted to a desired range by adjusting the blend ratio of the polymers.

[0023] In this specification, the "cured vinyl polymer" that is the target of measurement for recovery rate and elongation at break (i.e., the test piece) is a cured product obtained by using the vinyl polymer alone, or by a composition containing the vinyl polymer and not containing any components other than the solvent and curing components (specifically, the crosslinking agent and curing catalyst described later), in order to evaluate the recovery rate and elongation at break of the vinyl polymer itself. In terms of ease of curing, a cured product formed by a composition consisting of the vinyl polymer and the curing components, or a composition consisting of the vinyl polymer, a solvent and the curing components, can preferably be used as the cured vinyl polymer.

[0024] For example, in the case of a vinyl polymer having a crosslinkable silyl group as a crosslinkable functional group, a cured product formed from a composition consisting of the vinyl polymer having a crosslinkable silyl group and a curing catalyst, or a composition consisting of the vinyl polymer having a crosslinkable silyl group, a curing catalyst, and a solvent, is used as a test specimen. In this case, the amount of curing catalyst can be set as appropriate, but for example, it can be 0.3 to 3.0 parts by mass per 100 parts by mass of the vinyl polymer having a crosslinkable silyl group. Details of the procedure for preparing the specimens for measurement of recovery rate and elongation at break follow the method described in the examples below.

[0025] As long as the vinyl polymer (P) has crosslinkable functional groups and possesses the characteristics of and <ii> described above, the type and structure of the monomers constituting the vinyl polymer (P) are not particularly limited. Preferred embodiments of the vinyl polymer (P) will be described in detail below.

[0026] (Monomer) As the monomer constituting the vinyl polymer (P), a vinyl monomer having a crosslinkable functional group (hereinafter also referred to as "crosslinkable group-containing vinyl monomer") is preferably used because it allows for the easy acquisition of a vinyl polymer having a crosslinkable functional group.

[0027] Specific examples of crosslinkable group-containing vinyl monomers include, for example, crosslinkable silyl group-containing vinyl compounds, unsaturated carboxylic acids, unsaturated acid anhydrides, hydroxyl group-containing vinyl compounds, epoxy group-containing vinyl compounds, primary or secondary amino group-containing vinyl compounds, oxazoline group-containing vinyl compounds, and isocyanate group-containing vinyl compounds.

[0028] Examples of crosslinkable silyl group-containing vinyl compounds include vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyldimethylmethoxysilane; trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, methyldimethoxysilylpropyl (meth)acrylate, dimethylmethoxysilylpropyl (meth)acrylate, trimethoxysilylmethyl (meth)acrylate, methyldimethoxysilylmethyl (meth)acrylate, and 8-(trimethoxysilyl) (meth)acrylate. Examples include alkoxysilyl group-containing (meth)acrylic acid esters 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. Crosslinkable silyl group-containing vinyl compounds are preferable because a crosslinked structure is formed by dehydration condensation between crosslinkable silyl groups, which allows for efficient polymerization and subsequent crosslinking reactions when producing vinyl polymers.

[0029] 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.). Examples of unsaturated anhydrides include maleic anhydride, itaconic anhydride, and citraconic anhydride.

[0030] Examples of hydroxyl group-containing vinyl compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and mono(meth)acrylic acid esters of polyalkylene glycols (e.g., polyethylene glycol, polypropylene glycol, etc.).

[0031] Examples of epoxy group-containing vinyl compounds include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0032] 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.

[0033] Examples of oxazoline group-containing vinyl compounds include 2-isopropenyl-2-oxazoline and 2-vinyl-2-oxazoline. Examples of isocyanate group-containing vinyl compounds include 2-isocyanatoethyl (meth)acrylate and (meth)acryloyl isocyanate.

[0034] Among the crosslinkable group-containing vinyl monomers, crosslinkable silyl group-containing vinyl compounds are preferred because they yield cured products that exhibit excellent elongation and strength at break, as well as good weather resistance.

[0035] ・The other vinyl monomer vinyl polymer (P) may contain a structural unit derived from a crosslinkable group-containing vinyl monomer (hereinafter also referred to as "crosslinkable group-containing vinyl unit") and a structural unit derived from a vinyl monomer different from the crosslinkable group-containing vinyl monomer (hereinafter also referred to as "the other vinyl monomer"). The other vinyl monomer may be any monomer copolymerizable with the crosslinkable group-containing vinyl monomer and is not particularly limited. Specific examples of the other vinyl monomer include (meth)acrylic acid alkyl ester compounds, aliphatic cyclic ester compounds of (meth)acrylic acid, aromatic ester compounds of (meth)acrylic acid, the following general formula (1): CH ２ =CR １ -C(=O)O-(R ２ O) ｎ -R ３ …(1) (In the general formula (1), R １ represents a hydrogen atom or a methyl group, R ２ represents a linear or branched alkylene group having 2 to 6 carbon atoms, and 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.) Compounds represented by, styrene-based compounds, maleimide compounds, amide group-containing vinyl compounds, fluorine-containing (meth)acrylic acid ester compounds, and the like can be mentioned.

[0036] Specific examples of alkyl (meth)acrylate compounds 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, and eicosyl (meth)acrylate.

[0037] Specific examples of aliphatic cyclic ester compounds 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, and dicyclopentanyl (meth)acrylate.

[0038] Specific examples of aromatic ester compounds of (meth)acrylic acid include phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxymethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, and 3-phenoxypropyl (meth)acrylate.

[0039] 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.

[0040] 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 formula (1). ２ These elements may be identical or different. That is, compounds in formula (1) where n is 2 or more may have different types of polyoxyalkylene structures within a single molecule, such as a block structure consisting of polyoxyethylene / polyoxypropylene.

[0041] Specific examples of compounds in which n in the above general formula (1) is 2 or more include polyoxyethylene (meth)acrylate, polyoxypropylene (meth)acrylate, polyoxybutylene (meth)acrylate, polyoxyethylene-polyoxypropylene (meth)acrylate, 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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, allyl chloride, and allyl alcohol.

[0047] It is preferable that the other vinyl monomers include alkyl (meth)acrylate compounds, as this makes it easier to obtain vinyl polymers with a low glass transition temperature (Tg) and excellent fluidity. As the alkyl (meth)acrylate compound, alkyl (meth)acrylates in which the alkyl group (R) contained in the ester portion (-COOR) has 1 to 20 carbon atoms are preferably used, as this makes it easier to obtain vinyl polymers with a low glass transition temperature (Tg) and excellent fluidity. It is more preferable that the alkyl (meth)acrylate compound constituting the vinyl polymer includes an alkyl (meth)acrylate having an alkyl group with 2 to 20 carbon atoms in the ester portion, even more preferable that it includes an alkyl (meth)acrylate having an alkyl group with 2 to 18 carbon atoms in the ester portion, and even more preferable that it includes an alkyl (meth)acrylate having an alkyl group with 4 to 18 carbon atoms in the ester portion. Furthermore, it is preferable that the vinyl polymer (P) includes structural units derived from the acrylic monomer, and it is more preferable that it includes structural units derived from the alkyl acrylate compound, as this allows for a polymer with excellent weather resistance and fluidity.

[0048] When considering the mechanical properties of the vinyl polymer (P), it is preferable that the vinyl polymer (P) has structural units derived from an alkyl (meth)acrylate ester having an alkyl group with 4 to 18 carbon atoms in the ester portion. From the viewpoint of achieving both fluidity and mechanical properties of the vinyl polymer (P), in the alkyl (meth)acrylate ester having an alkyl group with 4 to 18 carbon atoms in the ester portion, the number of carbon atoms in the alkyl group in the ester portion is preferably 4 to 16, and more preferably 4 to 15.

[0049] The method for introducing crosslinkable functional groups is not limited to polymerization using a crosslinkable group-containing vinyl monomer; other methods may also be used. Other methods for introducing crosslinkable functional groups include, for example, the following methods 1 and 2. Method 1: A method in which structural units derived from an unsaturated carboxylic acid are introduced into a vinyl polymer, and the carboxyl groups in the structural units derived from the unsaturated carboxylic acid are reacted (addition reaction) with a crosslinkable group-containing epoxy compound (preferably a crosslinkable silyl group-containing epoxy compound). Method 2: A method in which structural units derived from an epoxy group-containing vinyl compound are introduced into a vinyl polymer, and the epoxy groups in the structural units derived from the epoxy group-containing vinyl compound are reacted (addition reaction) with a crosslinkable group-containing amine compound (preferably a crosslinkable silyl group-containing amine compound).

[0050] The vinyl polymer (P) preferably contains multiple types of vinyl polymers with different average numbers of crosslinkable functional groups per molecule and molecular weight characteristics. Specifically, the vinyl polymer (P) preferably contains the following vinyl polymer (I) and vinyl polymer (II): Vinyl polymer (I): A polymer having a weight-average molecular weight (Mw) of 30,000 to 100,000, a molecular weight distribution (Mw / Mn) of 1.8 or less, and an average number of crosslinkable functional groups per molecule of 1.8 or more. Vinyl polymer (II): A polymer having a weight-average molecular weight (Mw) of 5,000 to 30,000, and an average number of crosslinkable functional groups per molecule of 0.2 to 0.9.

[0051] (Vinyl Polymer (I)) Vinyl polymer (I) is a polymer that can be a high molecular weight component in vinyl polymer (P), and has a greater number of crosslinkable functional groups per molecule than vinyl polymer (II). If the average number of crosslinkable functional groups per molecule of vinyl polymer (I) is 1.8 or more, the recovery rate of the cured product of vinyl polymer (P) can be increased. This makes it possible to further improve the weather resistance of cured products obtained using a curable resin composition containing vinyl polymer (P).

[0052] From the above viewpoint, the average number of crosslinkable functional groups in one molecule of vinyl polymer (I) is more preferably 2.0 or more, even more preferably 2.2 or more, even more preferably 2.4 or more, even more preferably 2.7 or more, and even more preferably 3.0 or more. Furthermore, in terms of being able to make the elongation at break of the cured product obtained using a curable resin composition containing vinyl polymer (P) even better, the average number of crosslinkable functional groups in one molecule of vinyl polymer (I) is preferably 8.0 or less, more preferably 7.0 or less, even more preferably 6.0 or less, and even more preferably 5.5 or less.

[0053] In vinyl polymer (I), the preferred range for the average number of crosslinkable functional groups per molecule can be set by appropriately combining the upper and lower limits described above. Specifically, in vinyl polymer (I), the average number of crosslinkable functional groups per molecule is preferably 1.8 to 8.0, more preferably 2.0 to 7.0, even more preferably 2.2 to 6.0, and most preferably 2.4 to 5.5.

[0054] Furthermore, the average number of crosslinkable functional groups in vinyl polymers is １ This can be calculated by 1H-NMR measurement and gel permeation chromatography (GPC) measurement. For example, to determine the average number of crosslinkable functional groups in a vinyl polymer having crosslinkable silyl groups as crosslinkable functional groups, first, identify the structural units constituting the polymer and determine the monomers used in polymerization, １ In the 1H-NMR spectrum, the polymer composition and the mole fraction of the crosslinkable silyl group-containing monomer can be calculated from the integral value of the signal originating from the hydrogen atom bonded to the carbon atom of the alkoxysisilane, which is observed around 3.5 ppm. Then, by multiplying this mole fraction by the number-average molecular weight (Mn) obtained by GPC measurement, the average number of crosslinkable silyl groups in one molecule can be calculated.

[0055] Regarding the weight-average molecular weight (Mw) of the vinyl polymer (I), if Mw is 30,000 or more, the strength and weather resistance of the cured product can be sufficiently enhanced when the cured product is manufactured using the vinyl polymer (P). Furthermore, if the Mw of the vinyl polymer (I) is 100,000 or less, good fluidity and coating properties of the vinyl polymer (P) can be ensured.

[0056] From the viewpoint of improving the strength and weather resistance of the cured product obtained using the vinyl polymer (P), the Mw of the vinyl polymer (I) is more preferably 35,000 or more, even more preferably 40,000 or more, and even more preferably 45,000 or more. Regarding the upper limit of the Mw of the vinyl polymer (I), from the viewpoint of ensuring the fluidity of the vinyl polymer (I), 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 of the vinyl polymer (I) is more preferably 35,000 to 95,000, even more preferably 40,000 to 90,000, and even more preferably 45,000 to 85,000. In this specification, the molecular weight of the vinyl polymer is the polystyrene equivalent value measured by GPC.

[0057] For vinyl polymer (I), the number-average molecular weight (Mn) in polystyrene equivalent, as measured by GPC, is preferably in the range of 18,000 to 80,000. From the viewpoint of strength and weather resistance of the cured product obtained using vinyl polymer (P), the Mn of vinyl polymer (I) is more preferably 20,000 or more, even more preferably 25,000 or more, and even more preferably 28,000 or more. Regarding the upper limit of Mn of vinyl polymer (I), from the viewpoint of sufficiently ensuring the fluidity of vinyl polymer (P), it is more preferably 75,000 or less, and even more preferably 70,000 or less. The range of Mn for vinyl polymer (I) is more preferably 18,000 to 75,000, and even more preferably 20,000 to 70,000.

[0058] For vinyl polymers (I), the molecular weight distribution (Mw / Mn) obtained by dividing the weight-average molecular weight (Mw) by the number-average molecular weight (Mn) is preferably 1.8 or less, more preferably 1.7 or less, and even more preferably 1.6 or less, from the viewpoint of obtaining a cured product with excellent tensile properties (such as elongation at break and breaking strength) and weather resistance. The lower limit of the molecular weight distribution (Mw / Mn) is not particularly limited, but for example, it is 1.1 or more.

[0059] Examples of monomers constituting vinyl polymer (I) include compounds similar to those exemplified above as crosslinkable group-containing vinyl monomers and other monomers. Vinyl polymer (I) is preferably obtained using crosslinkable group-containing vinyl monomers because it is easy to control the amount and position of the introduced crosslinkable groups. Furthermore, vinyl polymer (I) is preferably made containing structural units derived from crosslinkable silyl group-containing vinyl compounds because it is possible to obtain a cured product that exhibits excellent elongation and strength at break, as well as good weather resistance.

[0060] In terms of easily obtaining a vinyl polymer (P) with excellent fluidity, it is preferable that the vinyl polymer (I) contains structural units derived from an alkyl (meth)acrylate compound. Specific examples and preferred examples of alkyl (meth)acrylate compounds are as previously described.

[0061] The proportion of structural units derived from the (meth)acrylate alkyl ester compound in the vinyl polymer (I) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, and particularly preferably 90% by mass or more, relative to the total structural units constituting the vinyl polymer (I), in order to improve the fluidity of the vinyl polymer (P).

[0062] Furthermore, in vinyl polymer (I), the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 4 to 18 carbon atoms in the ester portion is preferably 25% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 60% by mass or more, relative to the total structural units constituting vinyl polymer (I), from the viewpoint of achieving both the fluidity and mechanical properties of vinyl polymer (P).

[0063] It is preferable for the vinyl polymer (I) to contain structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 or more carbon atoms in the ester portion, as this can improve the fluidity of the vinyl polymer (P) and further enhance the workability of the curable resin composition containing the vinyl polymer (P). Furthermore, by containing structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 or more carbon atoms in the ester portion of the vinyl polymer (I), compatibility with other polymers can be improved when blending polymers other than the vinyl polymer (P) (for example, polyoxyalkylene polymers, hereinafter also referred to as "other polymers") into the curable resin composition when preparing the curable resin composition containing the vinyl polymer (P). This further improves the mechanical properties of the cured product obtained from the curable resin composition.

[0064] When a vinyl polymer (I) contains a structural unit derived from an alkyl (meth)acrylate having an alkyl group with 10 or more carbon atoms in the ester portion, an alkyl (meth)acrylate having an alkyl group with 10 to 18 carbon atoms in the ester portion is preferably used as the alkyl (meth)acrylate constituting the structural unit, from the viewpoint of ensuring the fluidity of the vinyl polymer.

[0065] In vinyl polymer (I), the proportion of structural units derived from alkyl (meth)acrylate ester having an alkyl group with 10 or more carbon atoms in the ester portion is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, even more preferably 2% by mass or more, even more preferably 5% by mass or more, even more preferably 10% by mass or more, and particularly preferably 15% by mass or more, relative to the total structural units constituting vinyl polymer (I). Furthermore, from the viewpoint of improving the fluidity of vinyl polymer (P), the proportion of structural units derived from alkyl (meth)acrylate ester having an alkyl group with 10 or more carbon atoms in the ester portion is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to the total structural units constituting vinyl polymer (I).

[0066] The preferred range for the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 or more carbon atoms in the ester portion of the vinyl polymer (I) can be set by appropriately combining the upper and lower limits described above. Specifically, the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 or more carbon atoms in the ester portion of the vinyl polymer (I) is preferably 0.1 to 50% by mass, more preferably 1.0 to 45% by mass, even more preferably 2 to 40% by mass or more, and even more preferably 5 to 40% by mass or more, relative to the total structural units constituting the vinyl polymer (I).

[0067] To achieve a moderately high viscosity in the vinyl polymer (P), it is preferable that the vinyl polymer (I) contains a relatively small proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with two or fewer carbon atoms in the ester portion, such as methyl (meth)acrylate or ethyl (meth)acrylate. Specifically, in the vinyl polymer (I), the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with two or fewer carbon atoms in the ester portion is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 2% by mass or less, and even more preferably 1% by mass or less, relative to the total structural units constituting the vinyl polymer (I). Note that the vinyl polymer (I) does not need to contain structural units derived from alkyl (meth)acrylate esters having an alkyl group with two or fewer carbon atoms in the ester portion. That is, the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with two or fewer carbon atoms in the ester portion in the vinyl polymer (I) may be 0% by mass.

[0068] Preferably, the vinyl polymer (I) contains 0.1 to 50% by mass of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 or more carbon atoms in the ester portion, relative to the total structural units constituting the vinyl polymer (I), and the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 2 or fewer carbon atoms in the ester portion is 20% by mass or less relative to the total structural units constituting the vinyl polymer (I). In this case, it is preferable to ensure the fluidity (i.e., low viscosity) of the vinyl polymer (P), improve workability, and obtain a cured product with excellent tensile properties and weather resistance from a curable resin composition containing the vinyl polymer (P).

[0069] (Vinyl Polymer (II)) Vinyl polymer (II) is a polymer that can be a low molecular weight component in vinyl polymer (P), and has fewer crosslinkable functional groups per molecule than vinyl polymer (I). When the average number of crosslinkable functional groups per molecule of vinyl polymer (II) is 0.2 or more, the weather resistance of the cured product obtained from a curable resin composition containing vinyl polymer (P) can be sufficiently improved. From this viewpoint, the average number of crosslinkable functional groups per molecule of vinyl polymer (II) is more preferably 0.25 or more, and even more preferably 0.3 or more. Furthermore, in order to sufficiently ensure the elongation at break and weather resistance of the cured product obtained using a curable resin composition containing vinyl polymer (P), the average number of crosslinkable functional groups per molecule of vinyl polymer (II) is preferably 0.85 or less, more preferably 0.8 or less, and even more preferably 0.7 or less.

[0070] In vinyl polymer (II), the preferred range for the average number of crosslinkable functional groups per molecule can be set by appropriately combining the upper and lower limits described above. Specifically, in vinyl polymer (II), the average number of crosslinkable functional groups per molecule is preferably 0.2 to 0.85, more preferably 0.25 to 0.8, and even more preferably 0.3 to 0.7.

[0071] The weight-average molecular weight (Mw) of vinyl polymer (II) is 5,000 or more and 30,000 or less. By setting the Mw of vinyl polymer (II) to 5,000 or more and 30,000 or less, when a cured product is manufactured using vinyl polymer (P), the strength and weather resistance of the cured product can be improved while ensuring sufficient fluidity and workability of vinyl polymer (P).

[0072] From the viewpoint of improving the strength and weather resistance of the cured product obtained using the vinyl polymer (P), the Mw of the vinyl polymer (II) is more preferably 6,000 or more, even more preferably 6,500 or more, and even more preferably 7,000 or more. Regarding the upper limit of the Mw of the vinyl polymer (II), from the viewpoint of ensuring the fluidity of the vinyl polymer (P), it is more preferably 29,000 or less, even more preferably 28,000 or less, and even more preferably 25,000 or less. The range of Mw for the vinyl polymer (II) is more preferably 6,000 to 29,000, and even more preferably 6,500 to 28,000.

[0073] The molecular weight distribution (Mw / Mn) of the vinyl polymer (II) is preferably 6.0 or less, more preferably 5.5 or less, and even more preferably 5.0 or less, from the viewpoint of obtaining a cured product with excellent tensile properties and weather resistance. The lower limit of the molecular weight distribution (Mw / Mn) is not particularly limited, but from the viewpoint of ease of manufacture, it may be, for example, 1.5 or more, and may also be 2.0 or more.

[0074] The monomers constituting vinyl polymer (II) can also be the same compounds as those exemplified above as crosslinkable group-containing vinyl monomers and other monomers. Vinyl polymer (II) is preferably obtained using crosslinkable group-containing vinyl monomers because it is easier to control the amount of crosslinkable group introduced. Furthermore, vinyl polymer (II) preferably contains structural units derived from crosslinkable silyl group-containing vinyl compounds.

[0075] For similar reasons as explained for vinyl polymer (I), vinyl polymer (II) also preferably contains structural units derived from (meth)acrylate alkyl ester compounds. Specific examples and preferred examples of (meth)acrylate alkyl ester compounds are as previously described. The proportion of structural units derived from (meth)acrylate alkyl ester compounds in vinyl polymer (II) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, and even more preferably 90% by mass or more, relative to the total structural units constituting vinyl polymer (II).

[0076] For vinyl polymer (II), for the same reasons as explained for vinyl polymer (I), it is preferable that the ester portion has structural units derived from alkyl (meth)acrylate ester having an alkyl group with 4 to 18 carbon atoms. The proportion of structural units derived from alkyl (meth)acrylate ester having an alkyl group with 4 to 18 carbon atoms in the ester portion of vinyl polymer (II) is preferably 25% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 60% by mass or more, relative to the total structural units constituting vinyl polymer (II).

[0077] However, from the viewpoint of ensuring compatibility between the vinyl polymer (P) and other polymers, it is preferable that the proportion of structural units derived from (meth)acrylate alkyl ester having an alkyl group with 8 or more carbon atoms in the ester portion is 50% by mass or less, relative to the total structural units constituting the vinyl polymer (II). More preferably, the proportion of structural units derived from (meth)acrylate alkyl ester having an alkyl group with 8 or more carbon atoms in the ester portion is 40% by mass or less, and even more preferably 30% by mass or less, relative to the total structural units constituting the vinyl polymer (II). Furthermore, from the viewpoint of improving the fluidity of the vinyl polymer (P), it is preferable that the proportion of structural units derived from (meth)acrylate alkyl ester having an alkyl group with 8 or more carbon atoms in the ester portion in the vinyl polymer (II) is 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, and even more preferably 10% by mass or more, relative to the total structural units constituting the vinyl polymer (II).

[0078] The preferred range for the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 8 or more carbon atoms in the ester portion of the vinyl polymer (II) can be set by appropriately combining the upper and lower limits described above. Specifically, the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 8 or more carbon atoms in the ester portion of the vinyl polymer (II) is preferably 50% by mass or less, more preferably 0.1 to 50% by mass, even more preferably 5 to 50% by mass, even more preferably 10 to 50% by mass or more, even more preferably 10 to 40% by mass or more, and even more preferably 10 to 30% by mass, relative to the total structural units constituting the vinyl polymer (II).

[0079] Furthermore, with respect to the vinyl polymer (II), it is preferable that the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 2 or fewer carbon atoms in the ester portion is relatively small. Specifically, in the vinyl polymer (II), the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 2 or fewer carbon atoms in the ester portion is preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less, relative to the total structural units constituting the vinyl polymer (II).

[0080] In particular, the vinyl polymer (II) preferably contains 0.1 to 50% by mass of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 8 or more carbon atoms in the ester portion, relative to the total structural units constituting the vinyl polymer (II), and the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 2 or fewer carbon atoms in the ester portion is 20% by mass or less relative to the total structural units constituting the vinyl polymer (II).

[0081] (Structure of vinyl polymers (I) and (II)) The order of arrangement of monomers in vinyl polymers (I) and (II) is not particularly limited. Vinyl polymers (I) and (II) may each be random copolymers, block copolymers, alternating copolymers, or graft copolymers. Of these, vinyl polymer (I) is preferably a block copolymer because it is easy to control the position in which crosslinkable functional groups are introduced, thereby making it easier to obtain cured products with excellent tensile properties, weather resistance, and heat resistance. Furthermore, vinyl polymer (II) is preferably a random copolymer because it is easy to adjust the viscosity of vinyl polymer (P) and is relatively easy to synthesize and obtain.

[0082] (Block Copolymer) When a block copolymer is used as at least a part of the polymer constituting a vinyl polymer (P), the block copolymer only needs to have two or more polymer blocks with different polymer compositions, and its structure is not particularly limited. A preferred example of a block copolymer is a vinyl polymer having a polymer block (A) having a crosslinkable functional group and a polymer block (B) with a monomer composition different from polymer block (A).

[0083] • Polymer block (A) Examples of monomers constituting polymer block (A) include the compounds exemplified as specific examples of monomers constituting vinyl polymer (P). Polymer block (A) preferably has structural units derived from (meth)acrylate alkyl ester compounds, and more preferably has structural units derived from (meth)acrylate alkyl esters having an alkyl group with 2 to 18 carbon atoms.

[0084] In polymer block (A), the proportion of structural units derived from the (meth)acrylate alkyl ester compound is preferably 50% by mass or more, relative to the total structural units constituting polymer block (A), from the viewpoint of obtaining a vinyl polymer (P) with excellent mechanical properties and weather resistance. From this viewpoint, the proportion of structural units derived from the (meth)acrylate alkyl ester compound in polymer block (A) 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 the (meth)acrylate alkyl ester compound in polymer block (A) is, for example, 99% by mass or less, preferably 98% by mass or less, and more preferably 95% by mass or less, from the viewpoint of sufficiently obtaining the improvement effect by introducing crosslinkable functional groups.

[0085] In polymer block (A), the proportion of structural units derived from crosslinkable group-containing vinyl monomers (i.e., crosslinkable group-containing vinyl units) is preferably 1% by mass or more relative to the total structural units constituting polymer block (A). Setting the proportion of crosslinkable group-containing vinyl units to 1% by mass or more is advantageous because it allows for sufficient improvement of mechanical strength. The proportion of crosslinkable group-containing vinyl units in polymer block (A) is preferably 2% by mass or more, and more preferably 5% by mass or more. On the other hand, from the viewpoint of ensuring the flexibility of the vinyl polymer (P), the upper limit of crosslinkable group-containing vinyl units is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, relative to the total structural units constituting polymer block (A).

[0086] For polymer block (A), the number-average molecular weight (Mn) in polystyrene terms, as measured by GPC, is preferably in the range of 1,000 to 80,000. A Mn of 1,000 or more is preferable because it allows for sufficiently high strength and durability of the cured product when using the block copolymer. A Mn of 80,000 or less is preferable because it ensures good fluidity and coating properties.

[0087] From the viewpoint of the strength of the cured product, the Mn of polymer block (A) is more preferably 2,000 or more, even more preferably 3,000 or more, even more preferably 3,500 or more, and even more preferably 4,000 or more. Regarding the upper limit of Mn of polymer block (A), from the viewpoint of ensuring the fluidity of the block copolymer, it is more preferably 60,000 or less, even more preferably 40,000 or less, even more preferably 20,000 or less, and even more preferably 10,000 or less. The preferred range of Mn of polymer block (A) can be set by appropriately combining the upper and lower limits described above. The Mn of polymer block (A) is more preferably 2,000 to 60,000, even more preferably 3,000 to 40,000, even more preferably 3,500 to 20,000, and even more preferably 4,000 to 10,000.

[0088] Furthermore, for the polymer block (A), the weight-average molecular weight (Mw) in polystyrene equivalent, as measured by GPC, is preferably in the range of 1,200 to 100,000. An Mw of 1,200 or more is preferable because it allows for sufficiently high strength and durability of the cured product when the block copolymer is used to produce the cured product. An Mw of 100,000 or less is preferable because it ensures good fluidity and coating properties.

[0089] From the viewpoint of the strength of the cured product, the Mw of polymer block (A) is more preferably 2,000 or more, even more preferably 3,000 or more, even more preferably 4,000 or more, and even more preferably 5,000 or more. Regarding the upper limit of Mw of polymer block (A), from the viewpoint of ensuring the fluidity of the block copolymer, it is more preferably 80,000 or less, even more preferably 60,000 or less, even more preferably 40,000 or less, and even more preferably 15,000 or less. The preferred range of Mw of polymer block (A) can be set by appropriately combining the upper and lower limits described above. The Mw of polymer block (A) is more preferably 2,000 to 80,000, even more preferably 3,000 to 60,000, even more preferably 4,000 to 40,000, and even more preferably 5,000 to 15,000.

[0090] Furthermore, if a block copolymer has multiple polymer blocks (A), the number-average molecular weight of polymer block (A) represents the sum of the number-average molecular weights of all polymer blocks (A). For example, if the block copolymer is an (A)-(B)-(A) triblock composed of polymer block (A) / polymer block (B) / polymer block (A), then the "number-average molecular weight of polymer block (A)" means the sum of the number-average molecular weights of the two polymer blocks (A) that the block copolymer possesses. The same applies to the weight-average molecular weight and polymer block (B).

[0091] The molecular weight distribution (Mw / Mn) of the polymer block (A) is preferably 1.8 or less, more preferably 1.75 or less, even more preferably 1.7 or less, and even more preferably 1.5 or less, from the viewpoint of obtaining a cured product with excellent tensile properties (such as elongation at break and tensile strength) and weather resistance. The lower limit of the molecular weight distribution (Mw / Mn) may be, for example, 1.05 or more, or 1.1 or more.

[0092] • Polymer block (B) Examples of monomers constituting polymer block (B) include the compounds exemplified as specific examples of monomers constituting vinyl polymer (P). Polymer block (B) is preferably a polymer in which (meth)acrylate alkyl ester compounds are the main structural unit, in order to obtain a vinyl polymer (P) with excellent flexibility. Among these, it is more preferable that the polymer is in which (meth)acrylate alkyl esters having an alkyl group with 2 to 18 carbon atoms in the ester portion are the main structural unit, and it is even more preferable that the polymer is in which (meth)acrylate alkyl esters having an alkyl group with 4 to 18 carbon atoms in the ester portion are the main structural unit.

[0093] In polymer block (B), the proportion of structural units derived from the (meth)acrylate alkyl ester compound is preferably 50% by mass or more, relative to the total structural units constituting polymer block (B), from the viewpoint of obtaining a vinyl polymer with excellent mechanical properties. More preferably, the proportion of structural units derived from the (meth)acrylate alkyl ester compound 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, and even more preferably 90% by mass or more.

[0094] When considering the fluidity of the block copolymer, it is preferable that polymer block (B) has structural units derived from alkyl acrylate esters having an alkyl group with 4 to 8 carbon atoms in the ester portion. Furthermore, when preparing a curable resin composition containing the block copolymer, if compatibility with other polymers (e.g., polyoxyalkylene polymers) to be blended into the curable resin composition is considered, it is preferable that polymer block (B) has structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 or more carbon atoms in the ester portion, and more preferably that it has structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 to 18 carbon atoms in the ester portion.

[0095] In polymer block (B), the proportion of structural units derived from alkyl (meth)acrylate ester having an alkyl group with 4 to 8 carbon atoms in the ester portion is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to the total structural units constituting polymer block (B), from the viewpoint of obtaining a block copolymer that exhibits sufficient fluidity and excellent mechanical properties.

[0096] Furthermore, the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 or more carbon atoms (preferably 10 to 18 carbon atoms) in the ester portion is preferably 1% by mass or more, and more preferably 5% by mass or more, relative to the total structural units constituting polymer block (B), from the viewpoint of improving compatibility with other polymers. As for the upper limit, it is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less, and even more preferably 30% by mass or less, relative to the total structural units constituting polymer block (B).

[0097] Polymer block (B) may further have crosslinkable functional groups. If polymer block (B) has crosslinkable functional groups, examples of such crosslinkable functional groups include those exemplified as crosslinkable functional groups of vinyl polymers. However, from the viewpoint of forming a uniform crosslinked structure, it is preferable to concentrate the crosslinking points on polymer block (A). From this viewpoint, it is preferable that the ratio of structural units derived from the crosslinkable group-containing vinyl monomer to the total structural units constituting polymer block (B) is less than the ratio of structural units derived from the crosslinkable group-containing vinyl monomer to the total structural units constituting polymer block (A).

[0098] Specifically, the proportion of structural units derived from crosslinkable group-containing vinyl monomers (i.e., crosslinkable group-containing vinyl units) in polymer block (B) is preferably 15% by mass or less relative to the total structural units constituting polymer block (B). A proportion of 15% by mass or less of crosslinkable group-containing vinyl units in polymer block (B) is preferable in that it can sufficiently ensure the flexibility of the block copolymer. The proportion of crosslinkable group-containing vinyl units in polymer block (B) is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less, and even more preferably 1% by mass or less, relative to the total structural units constituting polymer block (B).

[0099] For polymer block (B), the number-average molecular weight (Mn) in polystyrene terms, as measured by GPC, is preferably in the range of 9,000 to 250,000. When Mn is 9,000 or higher, the strength and durability of the cured product can be sufficiently high when the block copolymer is used to produce the cured product. When Mn is 250,000 or lower, good fluidity and coating properties can be ensured. Furthermore, by having Mn in the above range for polymer block (B), the molecular weight of the molecular chain portion corresponding to the distance between crosslinking points can be sufficiently ensured.

[0100] From the viewpoint of the strength of the cured product, the Mn of polymer block (B) is more preferably 14,000 or more, even more preferably 19,000 or more, even more preferably 23,000 or more, and even more preferably 25,000 or more. Regarding the upper limit of Mn of polymer block (B), from the viewpoint of ensuring the fluidity of the polymer, it is more preferably 150,000 or less, and even more preferably 100,000 or less. The preferred range of Mn of polymer block (B) can be set by appropriately combining the upper and lower limits described above. The Mn of polymer block (B) is more preferably 14,000 to 150,000, even more preferably 19,000 to 100,000, and even more preferably 23,000 to 80,000.

[0101] Furthermore, for the polymer block (B), the weight-average molecular weight (Mw) in polystyrene equivalent, as measured by GPC, is preferably in the range of 10,000 to 300,000. When Mw is 10,000 or higher, the strength and durability of the cured product can be sufficiently high when the cured product is manufactured using the block copolymer. When Mw is 300,000 or lower, good fluidity and coating properties can be ensured, and the molecular weight of the molecular chain portion corresponding to the distance between crosslinking points can be sufficiently ensured.

[0102] From the viewpoint of the strength of the cured product, the Mw of polymer block (B) is more preferably 15,000 or more, even more preferably 20,000 or more, even more preferably 25,000 or more, and even more preferably 30,000 or more. Regarding the upper limit of Mw of polymer block (B), from the viewpoint of ensuring the fluidity of the polymer, it is more preferably 250,000 or less, and even more preferably 200,000 or less. The preferred range of Mw of polymer block (B) can be set by appropriately combining the upper and lower limits described above. The Mw of polymer block (B) is more preferably 15,000 to 250,000, even more preferably 20,000 to 200,000, and even more preferably 30,000 to 200,000.

[0103] The molecular weight distribution (Mw / Mn) of polymer block (B) is preferably 3.0 or less from the viewpoint of obtaining a polymer with excellent weather resistance. More preferably, the molecular weight distribution of polymer block (B) is 2.5 or less, even more preferably 2.2 or less, and even more preferably 2.0 or less. The lower limit of the molecular weight distribution of polymer block (B) is not particularly limited, but from the viewpoint of ease of manufacture, it is, for example, 1.05 or more.

[0104] The structure of a block copolymer having a polymer block (A) and a polymer block (B) can be, for example, an (A)-(B) diblock composed of polymer block (A) and polymer block (B), an (A)-(B)-(A) triblock composed of polymer block (A) / polymer block (B) / polymer block (A), a (B)-(A)-(B) triblock composed of polymer block (B) / polymer block (A) / polymer block (B), and an (A)-(B)-(A)-(B)-(A) pentablock composed of polymer block (A) / polymer block (B) / polymer block (A) / polymer block (B) / polymer block (A). Furthermore, the block copolymer may further have polymer blocks (C) other than polymer block (A) and polymer block (B). Examples of monomers constituting polymer block (C) include the compounds exemplified as specific examples of monomers constituting vinyl polymers (P).

[0105] Of these, triblock polymers are preferred, and (A)-(B)-(A) triblock polymers are more preferred, in that they allow for easy manufacturing while maintaining excellent weather resistance by using as few blocks as possible. With this structure, polymer blocks (A) having structural units derived from crosslinkable group-containing vinyl monomers act as crosslinking segments, making it easier to form a uniform crosslinked structure while ensuring molecular weight between crosslinking points, and thus enabling high mechanical strength and weather resistance of the resulting cured product.

[0106] In block copolymers, the ratio of polymer block (A) and polymer block (B) is not particularly limited, but from the viewpoint of sufficiently introducing crosslinking points into the block copolymer and obtaining a polymer with high mechanical strength and weather resistance, it is preferable that the ratio of polymer block (A) be 2 parts by mass or more per 100 parts by mass of the total amount of polymer block (A) and polymer block (B). The ratio of polymer block (A) is more preferably 4 parts by mass or more, even more preferably 6 parts by mass or more, even more preferably 8 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the total amount of polymer block (A) and polymer block (B). The upper limit of the polymer block (A) content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the total amount of polymer block (A) and polymer block (B).

[0107] • Production of block copolymers The polymerization method for obtaining block copolymers is not particularly restricted as long as it has two or more polymer blocks. For example, various controlled polymerization methods such as living radical polymerization and living anionic polymerization can be used to obtain block copolymers with precisely controlled molecular weight and molecular weight distribution. Alternatively, 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, can be applied to a wide range of monomers, and can produce a cured product with excellent heat resistance by reducing the content of metal components that may affect durability at high temperatures.

[0108] When producing block copolymers 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.

[0109] 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.).

[0110] 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.

[0111] 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 block copolymer of an even higher order than the triblock (for example, an (A)-(B)-(A)-(B)-(A) pentablock) can be obtained as a block copolymer.

[0112] 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). 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.

[0113] 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 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 mol of RAFT agent. The amount of polymerization initiator used per mol of RAFT agent is preferably 0.01 to 0.5 mol, and more preferably 0.05 to 0.4 mol.

[0114] 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.

[0115] 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 that can dissolve monomers as the polymerization solvent, and more preferable to use an organic solvent that can dissolve monomers.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] In order to easily obtain block copolymers in which the amount and position of introduced crosslinkable functional groups are controlled, it is preferable to carry out polymerization in the polymerization step of vinyl monomers while continuously or intermittently supplying at least a portion of the total amount of crosslinkable group-containing vinyl monomers into the reactor. This method is thought to suppress variations in the number of crosslinkable functional groups per polymer molecule and to introduce a uniform number of crosslinkable functional groups to each polymer. In other words, it is thought that the proportion of molecules with more crosslinkable functional groups than the average number of crosslinkable functional groups per polymer molecule, molecules with fewer crosslinkable functional groups than the average number, and molecules without crosslinkable functional groups can be reduced. As a result, when a vinyl polymer (P) is crosslinked, variations in the crosslinked structure can be sufficiently suppressed, and as a result, a cured product with superior weather resistance can be obtained.

[0120] When obtaining a (A)-(B)-(A) triblock as a block copolymer, consisting of polymer block (A) / polymer block (B) / polymer block (A), for the reasons mentioned above, it is preferable that the triblock is produced in a method including the first polymerization step and the second polymerization step described above, where in the first polymerization step, at least a portion of the total amount of crosslinkable group-containing vinyl monomer used to produce polymer block (A) is continuously or intermittently supplied into the reactor while polymerization is carried out. In this case, crosslinkable functional groups can be introduced into polymer blocks (A) located at both ends of the block copolymer while suppressing variations in the number of intermolecular crosslinkable functional groups. This makes it possible to obtain a cured product that exhibits excellent weather resistance and heat resistance.

[0121] When supplying crosslinkable group-containing vinyl monomers into a reactor continuously or intermittently during the production of polymer block (A), all of the crosslinkable group-containing vinyl monomers used in the production of polymer block (A) may be supplied to the reactor continuously or intermittently after polymerization has started (i.e., after the polymerization initiator has been added). Alternatively, a portion of the crosslinkable group-containing vinyl monomers used in the production of polymer block (A) may be charged into the reactor before polymerization has started (i.e., before the polymerization initiator has been added), and the remaining crosslinkable group-containing vinyl monomers may be supplied to the reactor continuously or intermittently after polymerization has started. It is preferable to charge a portion of the crosslinkable group-containing vinyl monomers used in the production of polymer block (A) into the reactor before polymerization has started, and to continuously or intermittently supply the remainder to the reactor after polymerization has started, as this has a high effect in homogenizing the number of crosslinkable functional groups per polymer molecule between molecules. In the following, among the vinyl monomers used in the production of polymer block (A), monomers that are loaded into the reactor before polymerization begins will also be referred to as "initial loading monomers," and monomers that are continuously or intermittently supplied to the reactor after polymerization begins will also be referred to as "continuous supply monomers."

[0122] For the crosslinkable group-containing vinyl monomer used in the production of polymer block (A), the ratio of the initially charged monomer to the continuously supplied monomer is preferably such that the ratio of the continuously supplied monomer to the total amount of crosslinkable group-containing vinyl monomer used in the production of polymer block (A) is 10 to 100% by mass. From the viewpoint of ensuring that the number of crosslinkable group-containing vinyl monomers introduced into each molecule of polymer block (A) is uniform, the ratio of the continuously supplied monomer to the total amount of crosslinkable group-containing vinyl monomer used in the production of polymer block (A) is more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 60% by mass or more. Furthermore, the ratio of the continuously supplied monomer to the total amount of crosslinkable group-containing vinyl monomer used in the production of polymer block (A) is more preferably 95% by mass or less, and even more preferably 90% by mass or less.

[0123] The method of supplying the continuously supplied monomer is not particularly limited, as long as the crosslinkable group-containing vinyl monomer can be supplied into the reactor over a predetermined time after the start of polymerization. For example, the crosslinkable group-containing vinyl monomer may be supplied into the reactor continuously (i.e., without interruption) or intermittently (i.e., intermittently). In order to introduce the crosslinkable group-containing vinyl monomer more uniformly to each molecule of polymer block (A), it is preferable to supply the crosslinkable group-containing vinyl monomer continuously after the start of polymerization.

[0124] The timing for starting the continuous or intermittent supply of crosslinkable group-containing vinyl monomers may be at the same time as the start of polymerization, or after a predetermined time has elapsed since the start of polymerization. From the viewpoint of introducing crosslinkable group-containing vinyl units to the ends of the vinyl polymer and thereby obtaining a cured product with excellent weather resistance and heat resistance, it is preferable to start the continuous or intermittent supply of crosslinkable group-containing vinyl monomers at the same time as or immediately after the start of polymerization. When supplying crosslinkable group-containing vinyl monomers into the reactor after the start of polymerization, it is preferable to supply the crosslinkable group-containing vinyl monomers over a period of, for example, 10 minutes to 8 hours, or over a period of 30 minutes to 6 hours.

[0125] 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.

[0126] The polymerization described above yields a polymer-containing solution containing a block copolymer having crosslinkable functional groups. The polymer-containing solution obtained by polymerization may be subjected to a known desolvation treatment to isolate and / or purify the 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.

[0127] If the block copolymer obtained by the above polymerization has thiocarbonylthio groups derived from the RAFT agent, a step of reacting the block copolymer with a nucleophile (hereinafter also referred to as the "post-treatment step") may be performed. It is presumed that by reacting the thiocarbonylthio groups of the block copolymer with a nucleophile, the thiocarbonylthio groups are converted to thiol groups, and these thiol groups react 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 groups have been removed.

[0128] 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.

[0129] 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.

[0130] 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 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, from the viewpoint 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.

[0131] (Random Copolymer) When a random copolymer is used as at least a part of the polymer constituting the vinyl polymer (P), the polymerization method for producing the random copolymer is not particularly limited. The random copolymer can be obtained by polymerizing the vinyl monomers described above using known radical polymerization methods such as solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization. Of these, solution polymerization is preferred because it allows for easy control of the molecular weight and structure of the random copolymer.

[0132] In the case of solution polymerization, for example, the desired polymer can be obtained by charging a polymerization solvent and monomers into a reactor, adding a polymerization initiator, and carrying out polymerization. When carrying out polymerization, the method of charging each raw material, including monomers, may be a batch-type initial batch charging in which all raw materials are charged at once, a semi-continuous charging in which at least some of the raw materials are continuously supplied into the reactor, or a continuous polymerization method in which all raw materials are continuously supplied and the resulting resin is continuously withdrawn from the reactor at the same time.

[0133] One example of a preferred polymerization method for obtaining random copolymers is a method (high-temperature continuous polymerization) in which raw materials containing monomers, polymerization solvents, and polymerization initiators are supplied to a pressurized reactor at a constant rate, while the raw materials are heated to a high temperature, and an amount of polymer solution corresponding to the amount of raw materials supplied is withdrawn from the reactor. According to the high-temperature continuous polymerization method, random copolymers with low molecular weight and low viscosity can be obtained. Furthermore, when producing random copolymers by the high-temperature continuous polymerization method, molecular weight control can be suitably achieved even when the amount of polymerization initiator and chain transfer agent used is reduced, and the amount of impurities can be reduced.

[0134] Organic solvents can preferably be used as polymerization solvents. Examples of organic solvents include cyclic ethers such as tetrahydrofuran and dioxane; chain ethers such as methyl orthoformate and trimethyl orthoacetate; aromatic hydrocarbons such as benzene, toluene, and xylene; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, secondary butyl alcohol, isobutyl alcohol, tertiary butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 3-methyl-1-butanol, 1-hexanol, 2-hexanol, 3-methyl-3-pentanol, 1-heptanol, 1-octanol, 2-ethylhexanol, and 3-ethyl-3-hexanol; and mixed solvents of two or more of these. The amount of polymerization solvent used is preferably 5 to 180 parts by mass, and more preferably 10 to 150 parts by mass, per 100 parts by mass of the total amount of monomers.

[0135] As polymerization initiators, known radical polymerization initiators such as organic peroxides, inorganic peroxides, and azo compounds can be used, and are not particularly limited. Specific examples of polymerization initiators include, as organic peroxides, di-tert-butyl peroxide, di-tert-hexyl peroxide, cyclohexanone peroxide, dibenzoyl peroxide, 3,3,5-trimethylcyclohexanone peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide, and 2,5-dimethyl-2,5-di(benzoylperoxy)hexane. Examples of inorganic peroxides include potassium persulfate and sodium persulfate.

[0136] Examples of azo compounds include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), 2-(tert-butylazo)-2-cyanopropane, 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-methylpropane), and dimethyl2,2'-azobis(2-methylpropionate).

[0137] Furthermore, a redox-type polymerization initiator consisting of a known oxidizing agent and a reducing agent may be used as the polymerization initiator. Examples of redox-type polymerization initiators include those using sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, ferrous sulfate, etc. as reducing agents, and potassium peroxodisulfate, hydrogen peroxide, tert-butyl hydroperoxide, etc. as oxidizing agents. In addition, a known chain transfer agent may be used in combination with the polymerization initiator. When producing random copolymers, organic peroxides can be preferably used as polymerization initiators because their molecular weight can be easily controlled within a desired range.

[0138] In the production of random copolymers, the amount of polymerization initiator used is, for example, 0.01 to 20 parts by mass, preferably 0.05 to 15 parts by mass, per 100 parts by mass of the total amount of monomers used for polymerization. Furthermore, in the above reaction, the polymerization temperature is preferably in the range of 150°C to 350°C. More preferably, the polymerization temperature is 160°C or higher, and even more preferably 170°C or higher. The upper limit of the polymerization temperature is more preferably 330°C or lower, even more preferably 310°C or lower, and even more preferably 290°C or lower. When polymerization is carried out by high-temperature continuous polymerization, the residence time of the raw materials is, for example, 2 to 60 minutes. The pressure during polymerization should be a pressure that can maintain the polymerization temperature.

[0139] Other methods for synthesizing random copolymers include, for example, the bulk polymerization method described in Japanese Patent Publication No. 57-502171, Japanese Patent Publication No. 59-6207, and Japanese Patent Publication No. 60-215007. Furthermore, by treating the product of bulk polymerization with a thin-film evaporator or the like to remove volatile components from the product, and then treating it with a purification apparatus such as the one shown in Japanese Patent Publication No. 2009-221265, the low molecular weight components in the product can be reduced. This makes it possible to obtain polymers with higher purity.

[0140] (Vinyl polymer (I) / Vinyl polymer (II)) When vinyl polymer (P) contains vinyl polymer (I) and vinyl polymer (II), from the viewpoint of improving the tensile properties and weather resistance of the cured product, it is preferable to use equal amounts of vinyl polymer (I) and vinyl polymer (II), or to use a ratio of vinyl polymer (I) that is greater than that of vinyl polymer (II). Specifically, the mass ratio of vinyl polymer (I) to vinyl polymer (II), when expressed as vinyl polymer (I) / vinyl polymer (II), is preferably 50 / 50 to 90 / 10. In order to further improve the tensile properties and weather resistance of the cured product while lowering the viscosity of vinyl polymer (P) and improving the workability of the curable resin composition containing vinyl polymer (P), the mass ratio of vinyl polymer (I) to vinyl polymer (II) is more preferably 50 / 50 to 80 / 20, and even more preferably 50 / 50 to 70 / 30.

[0141] Here, in a crosslinked structure formed by a vinyl polymer having crosslinkable functional groups, if the distance between crosslinking points of the vinyl polymer 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 sufficiently distribute stress. In this respect, it is thought that the vinyl polymer (P) was able to form a crosslinked product with a sufficiently long distance between crosslinking points of the polymer and a uniform crosslinked structure. Furthermore, when the vinyl polymer (P) contains a vinyl polymer (I) which is a high molecular weight component and a vinyl polymer (II) which is a low molecular weight component, it is thought that the distance between crosslinking points of the crosslinked structure formed by the vinyl polymer (P) was made longer and a uniform crosslinked structure was formed by adjusting the average number of crosslinkable functional groups per polymer molecule in addition to the weight-average molecular weights of vinyl polymer (I) and vinyl polymer (II). As a result, it is thought that the cured product obtained by curing a curable resin composition containing vinyl polymer (P) was able to exhibit weather resistance that could sufficiently withstand the dynamic deformation of the cured product itself caused by temperature, humidity, etc. It is unclear why the crosslinked structure of vinyl polymer (P), which contains vinyl polymer (I) and vinyl polymer (II), takes the above-described structure. However, one hypothesis is that in the crosslinked structure formed by vinyl polymer (I), which is a high molecular weight component, the vinyl polymer (II), which is a low molecular weight component, caps the excess crosslinkable functional groups of vinyl polymer (I) that were not used in the crosslinking reaction, thereby ensuring a uniform crosslinked structure and sufficient distance between crosslinking points.

[0142] Curable Resin Compositions Vinyl polymers (P) are suitable for applications such as sealants, adhesives, sealants, and paints due to their high weather resistance. Vinyl polymers (P) can be used alone for applications such as sealants, adhesives, sealants, and paints, but they may also be used in the form of curable resin compositions in which various components such as known additives are blended as needed. For example, a curable resin composition can be obtained by blending the necessary crosslinking agent, curing accelerator (also called a curing catalyst), and other polymers having crosslinking functional groups, depending on the type of crosslinking functional group that the vinyl polymer (P) has. Furthermore, a cured product suitable for the application can be obtained by molding the curable resin composition and subjecting it to heat treatment or other treatments as needed.

[0143] Other polymers having crosslinkable functional groups Examples of other polymers having crosslinkable functional groups include hydrocarbon polymers such as polyoxyalkylene polymers having crosslinkable functional groups, polyester polymers having crosslinkable functional groups, polyurethane polymers having crosslinkable functional groups, polybutadiene polymers having crosslinkable functional groups, hydrogenated polybutadiene polymers having crosslinkable functional groups, and polyisobutylene polymers having crosslinkable functional groups; polyamide polymers; bisphenol polymers, etc. Among these, the curable resin composition of this disclosure preferably contains a polyoxyalkylene polymer having a crosslinkable functional group together with a vinyl polymer (Q) in terms of excellent mechanical properties of the cured product. Examples of crosslinkable functional groups that other polymers may have include the groups exemplified as crosslinkable functional groups that the vinyl polymer (Q) may have.

[0144] Polyoxyalkylene polymers having crosslinkable functional groups (hereinafter also referred to as "crosslinkable polyoxyalkylene polymers") include polymers having repeating units represented by the following general formula (2): -O-R ４ -...(2) (In general formula (2), R ４ (This represents a divalent hydrocarbon group.)

[0145] In the above general formula (2), R ４ The following structure can be used as an example: ・-(CH ２ ) ｍ- (m is an integer from 1 to 10) ・-CH(CH ３ )CH ２ - ・-CH(C ２ H ５ )CH ２ - ・-C (CH ３ ) ２ CH ２ - The crosslinkable polyoxyalkylene polymer may contain one or more of the above repeating units in combination. Among these, R in the above general formula (2) is particularly advantageous in terms of workability. ４ is -CH(CH ３ )CH ２ - is preferable.

[0146] As the crosslinkable functional group of the crosslinkable polyoxyalkylene polymer, a crosslinkable silyl group is preferred in terms of its excellent compatibility with vinyl polymers (P), excellent mechanical properties of the cured product, and excellent weather resistance, and an alkoxysilyl group is more preferred in terms of its ease of controlling reactivity.

[0147] The method for producing crosslinkable polyoxyalkylene polymers is not particularly limited, but examples include polymerization using the corresponding epoxy compound or diol compound as a raw material, with an alkaline catalyst (e.g., KOH), polymerization using a transition metal compound-porphyrin complex catalyst, polymerization using a complex metal cyanide complex catalyst, and polymerization using a phosphazene.

[0148] The average number of crosslinkable silyl groups in one molecule of the crosslinkable polyoxyalkylene polymer is preferably in the range of 1 to 4, and more preferably in the range of 1.5 to 3, from the viewpoint of the mechanical properties and adhesiveness of the cured product. The position of the crosslinkable silyl groups in the crosslinkable polyoxyalkylene polymer is not particularly limited and can be in the side chains and / or terminals of the polymer. The crosslinkable polyoxyalkylene polymer incorporated into the curable resin composition may be either a linear polymer or a branched polymer, or a combination thereof.

[0149] For crosslinkable polyoxyalkylene polymers, the number-average molecular weight (Mn) in polystyrene terms, measured by GPC, is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 15,000 or more, from the viewpoint of mechanical properties. Regarding the upper limit of Mn, from the viewpoint of reducing viscosity and improving workability when coating the curable resin composition, it is preferably 60,000 or less, more preferably 50,000 or less, and even more preferably 40,000 or less. The range of Mn is preferably 5,000 to 60,000, more preferably 10,000 to 60,000, and even more preferably 15,000 to 50,000.

[0150] Commercially available crosslinkable polyoxyalkylene polymers may be used. Specific examples include Kaneka Corporation's "MS Polymer S203," "MS Polymer S303," "MS Polymer S810," "Cyril SAX510," "Cyril SAX220," "Cyril SAT200," "Cyril SAT350," "Cyril EST280," and "Cyril SAT30," as well as AGC Corporation's "Excester ES-S2410," "Excester ES-S2420," "Excester ES-S3430," and "Excester ES-S4530" (all product names).

[0151] When the curable resin composition contains a crosslinkable polyoxyalkylene polymer, its content is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, based on 100 parts by mass of the total amount of the vinyl polymer (P) and the crosslinkable polyoxyalkylene polymer. By setting the content of the crosslinkable polyoxyalkylene polymer within the above range, a cured product with high mechanical properties can be obtained. Furthermore, regarding the upper limit of the content of the crosslinkable polyoxyalkylene polymer, from the viewpoint of obtaining a cured product exhibiting excellent weather resistance, it is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less, based on 100 parts by mass of the total amount of the vinyl polymer (P) and the crosslinkable polyoxyalkylene polymer.

[0152] The mass ratio of the vinyl polymer (P) to the crosslinkable oxyalkylene polymer is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 to 90 / 10, and even more preferably 15 / 85 to 85 / 15, when expressed as vinyl polymer / oxyalkylene polymer.

[0153] Crosslinking agent (curing agent) Examples of crosslinking agents (curing agents) include epoxy compounds having two or more epoxy groups, isocyanate compounds having two or more isocyanate groups, aziridine compounds having two or more aziridinyl groups, oxazoline compounds having an oxazoline group, metal chelate compounds, and butylated melamine compounds. When a crosslinking agent is included, epoxy compounds, isocyanate compounds, and aziridine compounds are preferred among these, and isocyanate compounds are preferred in that they yield cured products with good physical properties under high-temperature conditions.

[0154] When the curable resin composition contains a crosslinking agent, its content is usually 0.01 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total of the vinyl polymer (P) and the polyoxyalkylene polymer. The crosslinking agent content is preferably 0.03 parts by mass to 5 parts by mass, more preferably 0.05 parts by mass to 2 parts by mass.

[0155] ・Curing accelerator (curing catalyst) Known compounds such as tin-based catalysts, titanium-based catalysts, and tertiary amines can be used as curing accelerators (curing catalysts). Among these, examples of tin-based catalysts include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetonate, and dioctyltin dilaurate. Specifically, examples include the product names "Neostan U-28," "Neostan U-100," "Neostan U-200," "Neostan U-220H," "Neostan U-303," and "SCAT-24" manufactured by Nitto Kasei Co., Ltd.

[0156] 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.

[0157] 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.

[0158] The amount of curing accelerator added is preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 2 parts by mass, based on 100 parts by mass of the total amount of vinyl polymer (P) and polyoxyalkylene polymer.

[0159] Other components to be added to the curable resin composition, in addition to those mentioned above, include plasticizers, fillers, pigments, adhesion promoters, dehydrating agents, antioxidants, UV absorbers, crosslinking agents (also known as curing agents), and oils.

[0160] Examples of plasticizers include liquid polyurethane resins, polyester plasticizers obtained from dicarboxylic acids and diols; ethers or esters of 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.

[0161] 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 10 to 90 parts by mass, based on 100 parts by mass of the total amount of vinyl polymer (P) and polyoxyalkylene polymer.

[0162] 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.

[0163] 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 polymer (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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] Other thermoplastic resins may be blended into a curable resin composition containing a vinyl polymer (P) to adjust its performance, coating properties, processability, etc. 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 blended.

[0168] 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.

[0169] Curable resin compositions containing vinyl polymers (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.

[0170] 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, comparative synthesis example, manufacturing example, and comparative manufacturing example are as follows.

[0171] <Analytical Method for Vinyl Polymers> <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

[0172] <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℃

[0173] <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)

[0174] <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 = B (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 - B) / (W0 - B) ... (2)

[0175] <Average number of crosslinkable silyl groups per molecule of vinyl polymer> The average number of crosslinkable silyl groups (alkoxysilyl groups) (hereinafter also referred to as "f(Si)") was calculated using the following formula from the amount (parts by mass) of monomers containing crosslinkable silyl groups, when the total amount of monomers used in the synthesis of the vinyl polymer is 100 parts by mass. f(Si) = {Amount of crosslinkable silyl group-containing monomer / (Molecular weight of crosslinkable silyl group-containing monomer × 100 / Mn)}

[0176] <Recovery Rate> The recovery rate [%] of the cured vinyl polymer was determined by the following procedure. 100 parts of vinyl polymer, 70 parts of methyl ethyl ketone, and 20 parts of propylene glycol methyl ether acetate were mixed and dissolved at room temperature. Then, 1 part of curing catalyst U-220H (dibutyltin diacetylacetonate, Neostan U-220H (manufactured by Nitto Chemical Co., Ltd.)) was added and mixed to prepare a mixture. This mixture was slowly poured into a box-shaped container made from a 2 mm thick Teflon® sheet so that the thickness of the dried film was 2 mm, and the container was left to stand at 23°C and 50% RH for more than one week to obtain a cured sheet. A tensile test dumbbell (JIS K 6251 Type 2) was prepared from the cured sheet and used as a test specimen. Using a tensile testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation), the test specimen was stretched at a speed of 5 mm / min until the gauge length (Dumbbell No. 2 type: 20 mm) became 32 mm, and held for 24 hours. Next, the test specimen was removed from the tensile testing machine and placed on a 2 mm thick Teflon® sheet, and after 1 hour the gauge length (L ２The following was measured. The measurement was performed in an environment with a temperature of 23°C and 50% RH. Furthermore, the recovery rate was calculated using the following formula if the test specimen could be stretched under the above measurement conditions and recovery behavior was observed in the test specimen after it was removed from the tensile testing machine. Recovery rate [%] = (L １ -L ２ ) / (L １ -L ０ ) × 100 Here, L ０ : Distance between gauge marks before elongation [mm] L １ : Distance between gauge marks when extended [mm] L ２ : Distance between gauge marks [mm] one hour after removal from the tensile testing machine. Here, L ０ = 20 [mm], L １ = 32 [mm].

[0177] <Tensile Properties> Tensile properties were measured using a tensile test dumbbell (JIS K 6251 Type 2), which was prepared in the same manner as the recovery rate measurement, and a tensile testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation). The measurements were taken under conditions of a temperature of 23°C, 50% RH, and a tensile speed of 200 mm / min, measuring the breaking strength (Ts, in MPa), elongation at breaking (El, in %), and strength at 50% elongation (M50, in MPa).

[0178] <Manufacturing and evaluation of vinyl polymer (I)> <Manufacturing of polymer block (A)> [Synthesis Example 1] Production of Polymer a-1 S,S-dibenzyltrithiocarbonate (hereinafter also called "DBTTC") (6.7 parts), 2,2'-azobis(2,4-dimethylvaleronitrile) (hereinafter also called "V-65") (0.29 parts), n-butyl acrylate (hereinafter also called "BA") (49.7 parts), ethyl acrylate (hereinafter also called "EA") (3.9 parts), n-tetradecyl acrylate (hereinafter also called "TDA") (25.0 parts), methyldimethoxysilylpropyl methacrylate (hereinafter also called "DMS") (5.3 parts), ethyl acetate (85.1 parts), and trimethyl orthoacetate (hereinafter also called "MOA") (21.3 parts) were charged into a 1 L flask equipped with a stirrer and thermometer. In a 1 L flask immediately after polymerization began, 16.0 parts of DMS were continuously added dropwise over 2 hours. Two hours after polymerization began, the temperature was raised to 70°C over 1 hour, and the reaction was continued at 70°C for another 4 hours. The reaction was then stopped by cooling to room temperature, yielding a solution containing polymer a-1. The molecular weight of the obtained polymer a-1 was measured by GPC (gel permeation chromatography) (polystyrene equivalent) and found to be Mn 4,610, Mw 6,160, and Mw / Mn 1.34. The reaction rates of each monomer, measured by gas chromatography (GC), were BA: 82%, EA: 89%, TDA: 83%, and DMS: 100%. The non-volatile content of the polymerization solution measured by the above method was 43.7%.

[0179] [Synthesis Examples 2-5 and Comparative Synthesis Examples 1-3] The same procedure as in Synthesis Example 1 was followed, except that the raw materials for the production of polymers a-2 to a-5 and ca-1 to ca-3 were used as shown in Table 1, to obtain polymers a-2 to a-5 and ca-1 to ca-3. The molecular weight of each polymer, the non-volatile content 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.

[0180]

[0181] The abbreviations for the compounds in Table 1 represent the following (the same applies to Tables 2-5): BA: n-butyl acrylate TDA: n-tetradecyl acrylate EA: ethyl acrylate DMS: methyl dimethoxysilylpropyl methacrylate TMS: trimethoxysilylpropyl methacrylate DBTTC: S,S-dibenzyl trithiocarbonate V-65: 2,2'-azobis(2,4-dimethylvaleronitrile) MOA: trimethyl orthoacetate

[0182] <Preparation of Triblock Copolymer> [Synthesis Example 6] Preparation 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 (4.5 parts of polymer a-1 (9.6 parts × 0.47 = 4.5 parts) as the purity was 47%), BA (70.5 parts), TDA (25.0 parts), 2,2'-azobis(2-methylbutyronitrile) (hereinafter also referred to as "ABN-E") (0.162 parts), ethyl acetate (20.0 parts), and MOA (5.0 parts). The mixture was thoroughly degassed by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70°C. Six hours after the start of polymerization, 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 charged during polymerization (total amount of monomer, control agent, initiator, and solvent) (unit: %). The molecular weights of the obtained triblock copolymer b-1 were Mn 76,900, Mw 115,700, and Mw / Mn 1.50. The reaction rates of each monomer, as measured by gas chromatography (GC), were BA: 90% and TDA: 86%. The obtained triblock copolymer b-1 is a triblock copolymer (polymer block (A) / polymer block (B) / polymer block (A)) having a (A)-(B)-(A) block structure, comprising polymer block (A) consisting of BA, EA, TDA, and DMS, and polymer block (B) consisting of BA and TDA.

[0183] [Synthesis Examples 7-11 and Comparative Synthesis Examples 4-6] The same procedure as in Synthesis Example 6 was followed, except that the raw materials used for the production of triblock copolymers b-2-b-6 and cb-1-cb-3 were as shown in Table 2, to obtain triblock copolymers b-2-b-6 and cb-1-cb-3. The molecular weight of each polymer and the reaction rate of each monomer were measured and are shown in Table 2.

[0184]

[0185] In Table 2, abbreviations other than those listed in Table 1 represent the following: ABN-E: 2,2'-azobis(2-methylbutyronitrile)

[0186] <Production of Pentablock Copolymer> [Synthesis Example 12] Production of Pentablock Copolymer c-1 A solution containing Triblock copolymer b-1 obtained in Synthesis Example 6 (99.04 parts) and MOA (0.23 parts) were charged, thoroughly degassed by nitrogen bubbling, and heated to 60°C. After the internal temperature stabilized at 60°C, ABN-E (0.015 parts) was added and polymerization was started. DMS (0.96 parts) was divided into four parts and added at 0 hours, 0.5 hours, 1.0 hours, and 1.5 hours after the start of polymerization, respectively. After 7 hours from 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 80,100, Mw 124,500, and Mw / Mn 1.55. Furthermore, the reaction rates of each monomer measured by gas chromatography (GC) were BA: 92%, EA: 91%, TDA: 90%, and DMS: 99%. The obtained pentablock copolymer c-1 has polymer blocks (A) consisting of BA, EA, TDA, and DMS, and polymer blocks (B) consisting of BA and TDA, 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) ≈ 15 / 85 (wt%).

[0187] [Synthesis Examples 13-18 and Comparative Synthesis Examples 7-9] The same procedure as in Synthesis Example 12 was followed, except that the raw materials used for the production of pentablock copolymers c-2-c-7 and cc-1-cc-3 were as shown in Table 3, to obtain pentablock copolymers c-2-c-7 and cc-1-cc-3. The molecular weight of each polymer was measured and is shown in Table 3. The composition ratio of polymer block (A) and polymer block (B) was also calculated and is shown in Table 3.

[0188]

[0189] <Post-treatment steps for pentablock copolymer> [Production Example 1] Production of triblock copolymer d-1 A solution containing block copolymer c-1 (100.0 parts) obtained in Synthesis Example 12 was thoroughly degassed by nitrogen bubbling, and then n-propylamine (0.36 parts) was charged in a constant temperature bath at 40°C to start the decomposition reaction of the thiocarbonyl group. After 5 hours, the reaction was stopped by cooling to room temperature to obtain a solution containing block copolymer d-1. 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 to recover the non-volatile component, block copolymer d-1. Block copolymer d-1 is a triblock copolymer (polymer block (A) / polymer block (B) / polymer block (A)) having a (A)-(B)-(A) block structure, comprising polymer block (A) composed of BA, EA, TDA, and DMS, and polymer block (B) composed of BA and TDA. It is a Michael adduct of a thiol formed by the decomposition of the thiocarbonylthio group of block copolymer c-1 by an amine, and a residual acrylate compound contained in block copolymer c-1. １¹H-NMR measurements confirmed that the hydrogen peak (4.8 ppm) bonded to the carbon adjacent to the thiocarbonylthio group, observed in block 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 (3) below) appeared. The molecular weight of block copolymer d-1 was Mn 43,700, Mw 65,700, and Mw / Mn = 1.50. The polymer composition calculated from the monomer charging ratio and the reaction rate of each monomer measured by gas chromatography (GC) was BA units: 72.1 mass%, TDA units: 25.8 mass%, EA units: 0.2 mass%, and DMS units: 1.9 mass%. The average number of crosslinkable silyl groups per molecule was calculated to be 3.6. The E-type viscosity of block copolymer d-1 was 179 Pa·s. Furthermore, a tensile test dumbbell (JIS K 6251 Type 2) was prepared using block copolymer d-1, and the recovery rate and tensile properties were measured. The results were: recovery rate 84%, elongation at break (El) 346%, breaking strength (Ts) 0.19 MPa, and strength at 50% elongation (M50) 0.05 MPa.

[0190] [Production Examples 2-7 and Comparative Production Examples 1-3] The same procedure as in Production Example 1 was performed, except that the raw materials were used as shown in Table 4 and the desolvation temperature was adjusted as appropriate, to obtain block copolymers d-2 to d-7 and cd-1 to cd-3. The molecular weight, polymer composition, average number of crosslinkable silyl groups per molecule, viscosity, recovery rate, and tensile properties of each polymer were measured and are shown in Table 4.

[0191]

[0192] <<Production and Evaluation of Vinyl Polymers (II)>> [Production Example 8] The temperature of a 1000 mL pressurized stirred tank reactor equipped with an oil jacket was maintained at 180°C. Next, while maintaining a constant reactor pressure, a monomer mixture consisting of 66 parts BA, 21 parts 2-ethylhexyl acrylate (hereinafter also referred to as "HA"), 10 parts methyl methacrylate (hereinafter also referred to as "MMA"), 3 parts TMS, 10 parts isopropyl alcohol (hereinafter also referred to as "IPA"), 15 parts MOA, 7 parts methyl ethyl ketone (hereinafter also referred to as "MEK"), and 0.08 parts di-tert-hexyl peroxide (manufactured by NOF Corporation, trade name "Perhexyl D", hereinafter also referred to as "DTHP") as a polymerization initiator 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 decreased temporarily, and then a temperature rise due to polymerization heat was observed, but the reaction temperature was maintained at 180-181°C by controlling the temperature of the oil jacket. The point at which the temperature stabilized after the start of supplying the monomer mixture was defined 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 A-1 as a vinyl polymer (II).

[0193] [Production Examples 9-15 and Comparative Production Examples 4-6] Random copolymers A-2 to A-8 and Ac-1 to Ac-3 were obtained by using the raw materials as shown in Table 5 and performing the same procedure as in Production Example 8, except that the reaction temperature was adjusted as appropriate. The molecular weight, polymer composition, average number of crosslinkable silyl groups per molecule, and viscosity of each polymer were measured and are shown in Table 5.

[0194]

[0195] In Table 5, abbreviations other than those listed in Tables 1-4 represent the following: HA: 2-ethylhexyl acrylate MMA: methyl methacrylate IPA: isopropyl alcohol MEK: methyl ethyl ketone DTHP: di-tert-hexyl peroxide

[0196] <<Production and Evaluation of Vinyl Polymer (P) and Curable Resin Composition>> [Example 1] (1) Production and Evaluation of Vinyl Polymer (P) Block copolymer d-1 obtained in Production Example 1 and random copolymer A-1 obtained in Production Example 8 were mixed in a mass ratio of vinyl polymer (I) / vinyl polymer (II) = 90 / 10 to produce vinyl polymer P-1 to be used as the base resin of the curable resin composition. The viscosity of vinyl polymer P-1 was measured to be 166 Pa·s. Furthermore, according to the analysis method for vinyl polymers described above, the recovery rate and tensile properties of the cured vinyl polymer P-1 were measured, and the recovery rate was 80%, the breaking strength (Ts) was 0.18 MPa, the elongation at breaking (El) was 323%, and the strength at 50% elongation (M50) was 0.05 MPa.

[0197] (2) Production and evaluation of curable resin composition Next, a curable resin composition was prepared by blending a vinyl polymer (vinyl polymer P-1 in Example 1) and each component according to the blending ratio shown in Table 6 below, using a conventional method.

[0198]

[0199] The details of the compounds in Table 6 are as follows: • Polyoxyalkylene polymer: Modified silicone Exester ES-S4530 (AGC Corporation) • UP-1020: Acrylic plasticizer, ARUFON® UP-1020 (Toagosei Co., Ltd.) • Light calcium carbonate: Viscolite-EL20 (Shiraishi Calcium Co., Ltd.) • Heavy calcium carbonate: Super SS (Maruo Calcium Co., Ltd.) • R-820: Titanium dioxide R-820 (Ishihara Sangyo Co., Ltd.) • B75: Anti-aging agent, Tinuvin B75 (Chiba Specialty Co., Ltd.) • SH6020: 3-(2-aminoethylamino)propyltrimethoxysilane, SH6020 (Toray Dow Corning Co., Ltd.) • SZ6300: Vinyltrimethoxysilane, SZ6300 (Toray Dow Corning Co., Ltd.) • U-220H: Tin catalyst (dibutyltin diacetylacetonate), Neostan U-220H (manufactured by Nitto Kasei Co., Ltd.)

[0200] The curable resin compositions prepared above were evaluated using the following method. The evaluation results for Example 1 are shown in Table 7.

[0201] (Dispensing Properties) The curable resin composition was filled into a cartridge and left to stand for 24 hours at 5°C, 10°C, and 23°C. After that, it was dispensed onto a substrate using a caulking gun (nozzle diameter 3 mm). The dispensing properties (workability) of the curable resin composition (liquid) were evaluated according to the following criteria: ○: Not hard and the entire amount can be easily dispensed. △: Hard and difficult to extrude, but the entire amount can be dispensed. ×: Hard and difficult to extrude, and the entire amount cannot be dispensed.

[0202] (Tensile Properties) A ​​curable resin composition was applied to a Teflon® sheet to a thickness of 2 mm at room temperature (25°C), and a cured sheet was prepared by curing it for 5 days under conditions of 23°C and 50% RH (relative humidity), followed by 1 day at 50°C in a saturated water vapor atmosphere. A tensile test dumbbell was prepared from the obtained cured sheet and measured using a tensile testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation). The shape of the tensile test dumbbell was based on type 3 of JIS K 6251, a Japanese Industrial Standard. Specifically, the breaking strength (Ts, in MPa), breaking elongation (El1, in %), and strength at 50% elongation (M50, in MPa) were measured under conditions of a tensile speed of 200 mm / min in an environment of 23°C and 50% humidity.

[0203] (Recovery Rate) The above tensile test dumbbell was stretched at a rate of 5 mm / min using a tensile testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation) until the distance between the gauge marks (Dumbbell Type 3: 20 mm) became 40 mm, and held for 24 hours. Next, the tensile test dumbbell was removed from the tensile testing machine and placed on a 2 mm thick Teflon® sheet, and the length between the gauge marks (L2) was measured after 1 hour. The measurement was performed in an environment of 23°C and 50% RH. The recovery rate was calculated using the following formula: Recovery Rate [%] = (L １ -L ２ ) / (L １ -L ０ ) × 100 Here, L ０ : Distance between gauge marks before elongation [mm] L １: Distance between gauge marks when extended [mm] L ２ : Distance between gauge marks [mm] one hour after removal from the tensile testing machine. Here, L ０ = 20 [mm], L １ = 40 [mm].

[0204] (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 with a 2-minute shower every 2 hours. After 300 hours, the test specimens were subjected to a tensile test under conditions of 23°C and 50% RH, and a tensile speed of 200 mm / min, to measure the elongation at break (El2, unit %). Furthermore, the elongation retention rate (unit %) was calculated by comparing it with the elongation at break (El1, unit %) obtained from the tensile property test. A higher elongation retention rate indicates better bulk weather resistance.

[0205] (Surface Weathering Resistance) A curable resin composition was applied to a Teflon® sheet to a thickness of 2 mm at room temperature (25°C), and cured for 5 days under conditions of 23°C and 50% RH (relative humidity), followed by 1 day of curing at 50°C in a saturated water vapor atmosphere to produce a cured sheet. The obtained cured sheet was placed in a metering weather meter (DAIPLA METAL WEATHER KU-R5NCI-A, manufactured by DAIPLA-WINTES, Inc.) and accelerated weathering tests were performed. The conditions were irradiation at 63°C, 70% RH, and illuminance of 80 mW / cm². ２ The test was conducted with a 2-minute shower every 2 hours. After 600 hours, 900 hours, and 1200 hours, the weather resistance was evaluated by visually checking the surface condition to see if cracks had formed and the degree of wrinkles and sagging, and was judged according to the following criteria: ○: No change in surface condition. △: No cracks have formed, but wrinkles and sagging have formed. ×: Cracks have formed.

[0206] [Examples 2-30 and Comparative Examples 1-9] Vinyl polymers P-2 to P-39 were produced as base resins for curable resin compositions by performing the same procedure as in Example 1, except that vinyl polymer (I) and vinyl polymer (II) were used as shown in Tables 7-11. The viscosity of vinyl polymers P-2 to P-39, as well as the recovery rate and tensile properties of the cured vinyl polymers, were measured. The results are shown in Tables 7-11.

[0207] Next, vinyl polymers P-2 to P-39 and each component were blended according to the blending ratios shown in Table 6 above, and the corresponding curable resin compositions were prepared by conventional methods. Each curable resin composition was then evaluated in the same manner as in Example 1. The results are shown in Tables 7 to 11. Note that "vinyl polymer" in Table 6 corresponds to vinyl polymers P-2 to P-39.

[0208]

[0209]

[0210]

[0211]

[0212]

[0213] As is clear from the results of Examples 1 to 30, curable resin compositions prepared using a vinyl polymer (P) with a viscosity of 170 Pa·s or less, a cured product recovery rate of 80% or more, and a breaking elongation of 150 to 500% exhibited excellent workability as well as excellent tensile properties and weather resistance of the cured product. Furthermore, when comparing Examples 1 to 5, which used the same combination of polymers for vinyl polymer (I) and vinyl polymer (II), the curable resin compositions of Examples 3 to 5, with a vinyl polymer (I) / vinyl polymer (II) ratio of 70 / 30 to 50 / 50, showed superior workability.

[0214] In contrast, the curable resin composition of Comparative Example 1, which was prepared using a vinyl polymer with a viscosity of 179 Pa·s instead of the vinyl polymer (P), had inferior workability compared to Examples 1 to 30. The curable resin compositions of Comparative Examples 2 and 3 were prepared using a vinyl polymer in which the cured product had uncured portions, making it impossible to measure the recovery rate and tensile properties (indicated as "with uncured portions" in Table 11). When the curable resin compositions of Comparative Examples 2 and 3 were used, the weather resistance (especially surface weather resistance) of the cured product formed by the curable resin composition was greatly reduced. These results suggest that a uniform crosslinked structure was not formed when the cured product was made in Comparative Examples 2 and 3, which led to the reduced weather resistance.

[0215] Furthermore, in Comparative Examples 4-6 and 9, where curable resin compositions were prepared using a vinyl polymer with a curing rate of less than 80% instead of vinyl polymer (P), the weather resistance of the cured products formed by the curable resin compositions was inferior. In Comparative Example 4, the number of crosslinkable silyl groups in one polymer molecule was too small. In Comparative Examples 5 and 6, the crosslinkable silyl groups could not be uniformly introduced between polymer molecules. As a result, a uniform crosslinked structure was not formed when the cured product was formed, leading to a curing rate of less than 80% for the vinyl polymer cured product, and consequently, the weather resistance of the cured product using the curable resin composition was reduced. In Comparative Example 9, the high proportion of structural units derived from alkyl (meth)acrylate esters having alkyl groups with 8 or more carbon atoms in vinyl polymer (II) resulted in insufficient compatibility between polymers (especially with polyoxyalkylene polymers), leading to a curing rate of less than 80% for the vinyl polymer cured product, and consequently, the weather resistance of the cured product using the curable resin composition was reduced.

[0216] The curable resin compositions of Comparative Examples 7 and 8 were prepared using a vinyl polymer (P) that, when its curing rate was measured, fractured during the measurement process, making it impossible to measure the recovery rate (indicated as "Fractured during measurement" in Table 11). When these curable resin compositions of Comparative Examples 7 and 8 were used, the weather resistance of the cured products formed by the curable resin compositions was significantly reduced. These results suggest that in Comparative Examples 7 and 8, the use of a vinyl polymer containing too many crosslinkable silyl groups per molecule prevented the formation of a uniform crosslinked structure in the cured product, resulting in reduced weather resistance.

[0217] From the above, the vinyl polymer of this disclosure exhibits excellent tensile properties (elongation at break and breaking strength) and resilience, and also exhibits good fluidity (low viscosity), resulting in excellent handling properties. Such vinyl polymers of this disclosure can be widely applied in various fields, including coatings for automotive parts, electrical appliances and medical-related products, packings, gaskets or hose materials, adhesive raw materials, building and civil engineering components, and daily necessities. Furthermore, curable resin compositions containing the vinyl polymer of this disclosure exhibit high weather resistance. Therefore, curable resin compositions of this disclosure can be applied as adhesives, sealants, paints, coatings, molding materials, rubber sheets, etc., and are particularly suitable for use as sealants.

[0218] 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 polymer having a crosslinkable functional group, wherein the viscosity of the vinyl polymer at 25°C is 170 Pa·s or less, the recovery rate of the cured product of the vinyl polymer is 80% or more, and the elongation at break is 150 to 500%.

2. The vinyl polymer according to claim 1, comprising: a vinyl polymer (I) having a weight-average molecular weight (Mw) of 30,000 to 100,000, a molecular weight distribution (Mw / Mn) of 1.8 or less, and an average number of crosslinkable functional groups per molecule of 1.8 or more; and a vinyl polymer (II) having a weight-average molecular weight (Mw) of 5,000 to 30,000, and an average number of crosslinkable functional groups per molecule of 0.2 to 0.

9.

3. The vinyl polymer according to claim 2, wherein the vinyl polymer (I) is a block copolymer.

4. The vinyl polymer according to claim 2, wherein the vinyl polymer (I) contains 0.1 to 50% by mass of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 10 or more carbon atoms in the ester portion, relative to the total structural units constituting the vinyl polymer (I).

5. The vinyl polymer according to claim 2, wherein the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 2 or fewer carbon atoms in the ester portion is 20% by mass or less, relative to the total structural units constituting the vinyl polymer (I).

6. The vinyl polymer according to claim 2, wherein the proportion of structural units derived from alkyl (meth)acrylate esters having an alkyl group with 8 or more carbon atoms in the ester portion is 50% by mass or less with respect to all structural units constituting the vinyl polymer (II).

7. The vinyl polymer according to claim 2, wherein the vinyl polymer (I) is a block copolymer consisting of polymer block (A) / polymer block (B) / polymer block (A).

8. The vinyl polymer according to claim 7, wherein the polymer block (A) has the crosslinkable functional group.

9. The vinyl polymer according to claim 2, wherein the vinyl polymer (II) is a random copolymer.

10. The vinyl polymer according to claim 2, wherein the vinyl polymer (I) is a block copolymer and the vinyl polymer (II) is a random copolymer.

11. The vinyl polymer according to claim 2, wherein the mass ratio of the vinyl polymer (I) to the vinyl polymer (II) is 50 / 50 to 90 / 10 when expressed as vinyl polymer (I) / vinyl polymer (II).

12. A curable resin composition comprising a vinyl polymer according to any one of claims 1 to 11 and an oxyalkylene polymer having a crosslinkable silyl group.

13. The curable resin composition according to claim 12, wherein the mass ratio of the vinyl polymer to the oxyalkylene polymer is 10 / 90 to 90 / 10 when expressed as vinyl polymer / oxyalkylene polymer.

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

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