WO2013011943A1 - Curable resin composition, coating, and article bearing film obtained by curing said coating - Google Patents

Abstract

Provided is a two-liquid curable resin composition containing the following: a composite resin (A) comprising a polysiloxane segment and a vinyl-polymer segment bound together via specific bonds, said polysiloxane segment having an epoxy group; and a polyisocyanate hardener (B). The percentage of the mass of the composite resin (A) that the polysiloxane segment constitutes, the epoxy equivalent weight of the composite resin (A), the hydroxyl equivalent weight of the vinyl-polymer segment, and the mass ratio of the polyisocyanate hardener (B) all fall within specific ranges. This curable resin composition exhibits excellent long-term storage stability in a one-liquid state wherein the hardener has not yet been added and can be used as a coating in a two-liquid state wherein the hardener has been added. Said coating cures well at room temperature, forming a cured film that exhibits excellent weather resistance and transparency.

Description

Curable resin composition, paint, and article having cured coating film of the paint

The present invention relates to a curable composition that can be cured at room temperature, has excellent transparency, and has excellent weather resistance after curing, a paint containing the curable resin composition, and an article having a cured coating film of the paint.

In recent years, polyester resins such as polyethylene terephthalate (PET), acrylic resins, ABS resins, polycarbonate resins and plastics such as fiber reinforced plastic (FRP) have been used for exterior construction in terms of lightness, impact resistance, workability and recyclability. Widely used in parts and automotive exterior parts. However, it has been pointed out that these synthetic resins suffer from yellowing and cracking due to long-term outdoor use.

In contrast, there is a method of imparting weather resistance to plastic by protecting the surface with a paint or the like. Polysiloxane-based paints and fluoroolefin-based paints have been reported so far as paints used for this, but polysiloxane-based paints that do not generate toxic halogen gas when incinerated are used for building exteriors, etc. It is suitably used in various fields.

As curable resin compositions for use in polysiloxane-based paints, the inventors previously described polymers having functional groups other than hydrolyzable silyl groups and hydrolyzable silyl groups, silanol groups and / or hydrolyzable silyls. A curable resin composition containing a resin obtained by condensation reaction of a polysiloxane having a group and a curing agent has been invented and disclosed (for example, see Patent Document 1). The cured coating film obtained from the curable resin composition is excellent in weather resistance and scratch resistance.
However, the curable resin composition is a resin that is cured by heat, and particularly when it is cured by heat, heating at a high temperature of 140 ° C. is required to impart high weather resistance to the cured coating film (Patent Document). 1 see Example 1). Therefore, there is a problem that the construction is difficult when the construction is performed outdoors such as a wall surface of a building, and a high weather resistance resin that can be cured at room temperature is demanded.

On the other hand, it is known that in the room temperature curable resin, compatibility between good curability and storage stability is a problem. In Patent Document 2, a resin obtained by further modifying a fatty acid-modified acrylic resin with a silicon resin as a resin that has good storage stability and can be cured at room temperature, and an epoxy group is introduced into the resin. In addition, a resin in which an epoxy group is opened and reacted during resin synthesis is disclosed. Although the resin can be cured at room temperature, since the produced resin is brown, there is a great problem in using it as an exterior paint.

International Publication No. 96/035755 Pamphlet JP 2001-122968 A

The problem to be solved by the present invention is a two-component curable resin composition that has excellent storage stability in a one-component state, can be cured at room temperature, and has excellent transparency, and contains the curable resin composition. It is to provide an article having a paint and a cured coating of the paint.

As a result of intensive studies, the present inventors have found that a two-component curability containing a composite resin in which a polysiloxane segment having an epoxy group and a vinyl polymer segment are bonded by a specific bond, and a polyisocyanate as a curing agent. A curable resin, which is a resin composition, wherein the mass ratio of the polysiloxane segment in the composite resin, the epoxy equivalent of the composite resin, the amount of hydroxyl groups in the vinyl polymer segment, and the mass ratio of the polyisocyanate are within a specific range The composition is excellent in long-term storage stability in a one-liquid state before adding a curing agent, and in a two-liquid state in which a curing agent is added, a cured coating having excellent curability and weather resistance after curing at room temperature and transparency. The inventors found that a film can be formed and completed the present invention.

That is, the present invention provides a polysiloxane segment (a1) having a structural unit represented by the general formula (1) and / or the general formula (2), a silanol group and / or a hydrolyzable silyl group, and an epoxy group. Resin composition containing a composite resin (A) in which a vinyl polymer segment (a2) having an alcoholic hydroxyl group is bonded by a bond represented by the general formula (3), and a polyisocyanate (B) The mass ratio of the polysiloxane segment (a1) in the solid content of the composite resin (A) is 20 to 70% by mass, and the epoxy equivalent of the solid content of the composite resin (A) is 900 to 17,000 g / eq, the hydroxyl value of the vinyl polymer segment (a2) is 55 to 200 mgKOH / g, and the mass ratio of the polyisocyanate (B) Providing a curable resin composition which is a 5 to 50% by weight of the total solids.

(In the general formulas (1) and (2), R ¹ , R ² and R ³ each independently represent —R ⁴ —CH═CH ₂ , —R ⁴ —C (CH ₃ ) ═CH ₂ , — A group having one polymerizable double bond selected from the group consisting of R ⁴ —O—CO—C (CH ₃ ) ═CH ₂ and —R ⁴ —O—CO—CH═CH ₂ (provided that R ⁴ Represents a single bond or an alkylene group having 1 to 6 carbon atoms.), An alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group, or 7 carbon atoms. Represents an aralkyl group of ˜12.)

(In the general formula (3), carbon atoms constitute a part of the vinyl polymer segment (a2), and silicon atoms bonded only to oxygen atoms constitute a part of the polysiloxane segment (a1). To do)

Further, the present invention is to provide an article characterized by having a paint containing the curable resin composition and a coating film formed using the paint.

Since the curable resin composition of the present invention is excellent in curability even at room temperature curing, it is difficult to cure by active energy rays or heat, it is particularly useful as a cured coating for outdoor enforcement or large buildings, cured products Is particularly useful as a coating for exterior building because it has long-term weather resistance outdoors. Moreover, although the curable resin composition of this invention is a 2 liquid type, the storage stability in the state of 1 liquid before mixing is also favorable, and it is excellent in the usefulness as a coating material. Further, since the curable resin composition and paint of the present invention are colorless, it can be suitably used as a top coat, undercoat, clear paint or enamel paint.

The curable resin composition of the present invention has a structural unit represented by the general formula (1) and / or the general formula (2), a silanol group and / or a hydrolyzable silyl group, and an epoxy group. A composite resin (A) in which a polysiloxane segment (a1) and a vinyl polymer segment (a2) having an alcoholic hydroxyl group are bonded by a bond represented by the general formula (3); and a polyisocyanate (B) A curable resin composition containing, wherein the mass ratio of the polysiloxane segment (a1) in the solid content of the composite resin (A) is 20 to 70% by mass, and the solid content of the composite resin (A) The epoxy equivalent is 900 to 17000 g / eq, the hydroxyl value of the vinyl polymer segment (a2) is 55 to 200 mg KOH / g, and the polyisocyanate Weight ratio of bets (B) are those from 5 to 50% by weight of the total solids.

(Composite resin (A))
The composite resin (A) used in the present invention comprises a structural unit represented by the general formula (1) and / or the general formula (2), a silanol group and / or a hydrolyzable silyl group, an epoxy group, A polysiloxane segment (a1) having the following (hereinafter simply referred to as polysiloxane segment (a1)), a vinyl polymer segment (a2) having an alcoholic hydroxyl group (hereinafter simply referred to as vinyl polymer segment (a2)), and Is a composite resin bonded by a bond represented by the general formula (3).

The silanol group and / or hydrolyzable silyl group possessed by the polysiloxane segment (a1) described later and the silanol group and / or hydrolyzable silyl group possessed by the vinyl polymer segment (a2) described below undergo a dehydration condensation reaction. Thus, the bond represented by the general formula (3) is generated. Accordingly, in the general formula (3), carbon atoms constitute a part of the vinyl polymer segment (a2), and silicon atoms bonded only to oxygen atoms constitute a part of the polysiloxane segment (a1). And
The form of the composite resin (A) is, for example, a composite resin having a graft structure in which the polysiloxane segment (a1) is chemically bonded as a side chain of the polymer segment (a2), or the polymer segment (a2). And a composite resin having a block structure in which the polysiloxane segment (a1) is chemically bonded.

(Composite resin (A) Polysiloxane segment (a1))
The polysiloxane segment (a1) in the present invention comprises a structural unit represented by the general formula (1) and / or the general formula (2), a silanol group and / or a hydrolyzable silyl group, and an epoxy group. It has a segment.

(Structural unit represented by general formula (1) and / or general formula (2))
Specifically, R ¹ , R ² and R ³ in the general formulas (1) and (2) are each independently —R ⁴ —CH═CH ₂ , —R ⁴ —C (CH ₃ ) ═ A group having one polymerizable double bond selected from the group consisting of CH ₂ , —R ⁴ —O—CO—C (CH ₃ ) ═CH ₂ , and R ⁴ —O—CO—CH═CH ₂ (provided that R ⁴ represents a single bond or an alkylene group having 1 to 6 carbon atoms.), An alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group, or 7 to 7 carbon atoms. 12 aralkyl groups are represented.

Examples of the alkylene group having 1 to 6 carbon atoms in R ⁴ include methylene group, ethylene group, propylene group, isopropylene group, butylene group, isobutylene group, sec-butylene group, tert-butylene group, and pentylene. Group, isopentylene group, neopentylene group, tert-pentylene group, 1-methylbutylene group, 2-methylbutylene group, 1,2-dimethylpropylene group, 1-ethylpropylene group, hexylene group, isohesylene group, 1-methylpentylene Group, 2-methylpentylene group, 3-methylpentylene group, 1,1-dimethylbutylene group, 1,2-dimethylbutylene group, 2,2-dimethylbutylene group, 1-ethylbutylene group, 1,1, 2-trimethylpropylene group, 1,2,2-trimethylpropylene group, 1-ethyl-2-me Examples include propylene group and 1-ethyl-1-methylpropylene group. Among these, R ⁴ is preferably a single bond or an alkylene group having 2 to 4 carbon atoms because of easy availability of raw materials.

Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, and isopentyl. Group, neopentyl group, tert-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 1,2-dimethylpropyl group, 1-ethylpropyl group, hexyl group, isohexyl group, 1-methylpentyl group, 2-methylpentyl Group, 3-methylpentyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 2,2-dimethylbutyl group, 1-ethylbutyl group, 1,1,2-trimethylpropyl group, 1,2 , 2-trimethylpropyl group, 1-ethyl-2-methylpropyl group, 1-ethyl-1-methylpropyl group and the like.
Examples of the cycloalkyl group having 3 to 8 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.
Examples of the aryl group include a phenyl group, a naphthyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 4-vinylphenyl group, and a 3-isopropylphenyl group.
Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, a diphenylmethyl group, and a naphthylmethyl group.

Further, when at least one of R ¹ , R ² and R ³ is a group having the polymerizable double bond, it can be cured by an active energy ray or the like, an active energy ray, and a silanol group and / or The two curing mechanisms of improving the crosslinking density of the coating film by the condensation reaction of hydrolyzable silyl groups can form a cured coating film with better wear resistance, acid resistance, alkali resistance and solvent resistance, It is difficult to use a curable resin composition, and it can be suitably used for a base material that easily undergoes thermal deformation, such as paints for exterior buildings and plastics.
Two or more groups having a polymerizable double bond are present in the polysiloxane segment (a1), preferably 3 to 200, more preferably 3 to 50, A coating film with more excellent wear resistance can be obtained. Specifically, when the content of polymerizable double bonds in the polysiloxane segment (a1) is 3 to 35% by mass, desired wear resistance can be obtained. The polymerizable double bond here is a general term for groups capable of performing a growth reaction by free radicals among vinyl group, vinylidene group or vinylene group. Moreover, the content rate of a polymerizable double bond shows the mass% in the polysiloxane segment of the said vinyl group, vinylidene group, or vinylene group.
As the group having a polymerizable double bond, all known functional groups containing the vinyl group, vinylidene group, and vinylene group can be used. Among them, —R ⁴ —C (CH ₃ ) = The (meth) acryloyl group represented by CH ₂ or —R ⁴ —O—CO—C (CH ₃ ) ═CH ₂ is rich in reactivity at the time of ultraviolet curing, and the vinyl polymer segment (described later) Good compatibility with a2).

The structural unit represented by the general formula (1) and / or the general formula (2) is a three-dimensional network-like polysiloxane structural unit in which two or three of the silicon bonds are involved in crosslinking. Since a three-dimensional network structure is formed but a dense network structure is not formed, gelation or the like is not caused and storage stability is also improved.

(Composite resin (A) Epoxy group)
The polysiloxane segment (a1) constituting the composite resin (A) in the present invention has an epoxy group, and the epoxy equivalent of the solid content of the composite resin (A) is 900 to 17000 g / eq. The range of 2500 to 6000 g / eq is particularly preferable because of excellent long-term storage stability and room temperature curability when a curable resin composition is obtained. When the epoxy equivalent of solid content is larger than 17000 g / eq, the composite resin (A) is easily gelled and cannot be stored for a long time. Moreover, when it is a case where it is less than 900 g / eq, when it mixes with a polyisocyanate (B) and it is set as a curable resin composition, it becomes impossible to cure at normal temperature.

In order to introduce an epoxy group into the polysiloxane segment (a1), an epoxy group-containing silane compound may be used during the production of the composite resin (A) described later. Epoxy group-containing silane compounds include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxyethoxysilane, γ-glycidoxypropyltriacetoxysilane, β -(3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxyethoxysilane, β- (3, 4-epoxycyclohexyl) ethyltriacetoxysilane, γ-glycidoxypropyldimethoxymethylsilane, γ-glycidoxypropyldiethoxymethylsilane, γ-glycidoxypropyldimethoxyethoxymethylsilane, γ-glycidoxypropyldiacetoxy Methylsilane, β- (3,4-epoxycyclohexyl) ethyldimethoxymethylsilane, β- (3,4-epoxycyclohexyl) ethyldiethoxymethylsilane, β- (3,4-epoxycyclohexyl) ethyldimethoxyethoxymethylsilane, β -(3,4-epoxycyclohexyl) ethyldiacetoxymethylsilane, γ-glycidoxypropyldimethoxyethylsilane, γ-glycidoxypropyldiethoxyethylsilane, γ-glycidoxypropyldimethoxyethoxyethylsilane, γ-glycyl Sidoxypropyldiacetoxyethylsilane, β- (3,4-epoxycyclohexyl) ethyldimethoxyethylsilane, β- (3,4-epoxycyclohexyl) ethyldiethoxyethylsilane, β- (3,4-epoxycyclohexyl) Tildimethoxyethoxyethylsilane, β- (3,4-epoxycyclohexyl) ethyldiacetoxyethylsilane, γ-glycidoxypropyldimethoxyisopropylsilane, γ-glycidoxypropyldiethoxyisopropylsilane, γ-glycidoxypropyldimethoxy Ethoxyisopropylsilane, γ-glycidoxypropyldiacetoxyisopropylsilane, β- (3,4-epoxycyclohexyl) ethyldiethoxyisopropylsilane, β- (3,4-epoxycyclohexyl) ethyldiethoxyisopropylsilane, β- ( 3,4-epoxycyclohexyl) ethyldimethoxyethoxyisopropylsilane, β- (3,4-epoxycyclohexyl) ethyldiacetoxyisopropylsilane, γ-glycidoxypropylmethoxydi Methylsilane, γ-glycidoxypropylethoxydimethylsilane, γ-glycidoxypropylmethoxyethoxydimethylsilane, γ-glycidoxypropylacetoxydimethylsilane, β- (3,4-epoxycyclohexyl) ethylmethoxydimethylsilane, β- (3,4-epoxycyclohexyl) ethylethoxydimethylsilane, β- (3,4-epoxycyclohexyl) ethylmethoxyethoxydimethylsilane, β- (3,4-epoxycyclohexyl) ethylacetoxydimethylsilane, γ-glycidoxypropyl Methoxydiethylsilane, γ-glycidoxypropylethoxydiethylsilane, γ-glycidoxypropylmethoxyethoxydiethylsilane, γ-glycidoxypropylacetoxydiethylsilane, β- (3,4-epoxy Cyclohexyl) ethylmethoxydiethylsilane, β- (3,4-epoxycyclohexyl) ethylethoxydiethylsilane, β- (3,4-epoxycyclohexyl) ethylmethoxyethoxydiethylsilane, β- (3,4-epoxycyclohexyl) ethylacetoxy Diethylsilane, γ-glycidoxypropylmethoxydiisopropylsilane, γ-glycidoxypropylethoxydiisopropylsilane, γ-glycidoxypropylmethoxyethoxydiisopropylsilane, γ-glycidoxypropylacetoxydiisopropylsilane, β- (3,4) -Epoxycyclohexyl) ethylmethoxydiisopropylsilane, β- (3,4-epoxycyclohexyl) ethylethoxydiisopropylsilane, β- (3,4-epoxycyclohexyl) Tylmethoxyethoxydiisopropylsilane, β- (3,4-epoxycyclohexyl) ethylacetoxydiisopropylsilane, γ-glycidoxypropylmethoxyethoxymethylsilane, γ-glycidoxypropylacetoxymethoxymethylsilane, γ-glycidoxypropylacetoxy Ethoxymethylsilane, β- (3,4-epoxycyclohexyl) ethylmethoxyethoxymethylsilane, β- (3,4-epoxycyclohexyl) ethylmethoxyacetoxymethylsilane, β- (3,4-epoxycyclohexyl) ethylethoxyacetoxymethyl Silane, γ-glycidoxypropylmethoxyethoxyethylsilane, γ-glycidoxypropylacetoxymethoxyethylsilane, γ-glycidoxypropylacetoxyethoxyethylsila , Β- (3,4-epoxycyclohexyl) ethylmethoxyethoxyethylsilane, β- (3,4-epoxycyclohexyl) ethylmethoxyacetoxyethylsilane, β- (3,4-epoxycyclohexyl) ethylethoxyacetoxyethylsilane, γ -Glycidoxypropylmethoxyethoxyisopropylsilane, γ-glycidoxypropylacetoxymethoxyisopropylsilane, γ-glycidoxypropylacetoxyethoxyisopropylsilane, β- (3,4-epoxycyclohexyl) ethylmethoxyethoxyisopropylsilane, β- (3,4-epoxycyclohexyl) ethylmethoxyacetoxyisopropylsilane, β- (3,4-epoxycyclohexyl) ethylethoxyacetoxyisopropylsilane, glycidoxymethyl Rutrimethoxysilane, glycidoxymethyltriethoxysilane, α-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltrimethoxysilane, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxy Silane, β-glycidoxypropyltrimethoxysilane, β-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane, γ-glycidoxypropyltriphenoxy Silane, α-glycidoxybutyltrimethoxysilane, α-glycidoxybutyltriethoxysilane, β-glycidoxybutyltrimethoxysilane, β-glycidoxybutyltriethoxysilane, γ-glycidoxybutyltrimethoxy Silane, γ-Glyci Xylbutyltriethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane, (3,4-epoxycyclohexyl) methyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltripropoxysilane, β- ( 3,4-epoxycyclohexyl) ethyltryptoxysilane, β- (3,4-epoxycyclohexyl) ethyltriphenoxysilane, γ- (3,4-epoxycyclohexyl) propyltrimethoxysilane, γ- (3,4-epoxy Cyclohexyl) propyltriethoxysilane, δ- (3,4-epoxycyclohexyl) butyltrimethoxysilane, δ- (3,4-epoxycyclohexyl) butyltriethoxysilane, glycidoxymethylmethyldimethoxysilane, glycidoxymethylmethyl Rudiethoxysilane, α-glycidoxyethylmethyldimethoxysilane, α-glycidoxyethylmethyldiethoxysilane, β-glycidoxyethylmethyldimethoxysilane, β-glycidoxyethylmethyldiethoxysilane, α-glycid Xylpropylmethyldimethoxysilane, α-glycidoxypropylmethyldiethoxysilane, β-glycidoxypropylmethyldimethoxysilane, β-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ- Glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldipropoxysilane, γ-glycidoxypropylmethyldibutoxysilane, γ-glycidoxypropylmethyldimethoxyethoxysilane, γ-glycidoxypropylmethyl Diphenoxysilane, γ-glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylethyldiethoxysilane, γ-glycidoxypropylethyldipropoxysilane, γ-glycidoxypropylvinyldimethoxysilane, γ-glycid Examples thereof include xylpropylvinyldiethoxysilane.

(Composite resin (A) Silanol group and / or hydrolyzable silyl group)
In the present invention, the silanol group is a silicon-containing group having a hydroxyl group directly bonded to a silicon atom. Specifically, the silanol group is a silanol group formed by combining an oxygen atom having a bond with a hydrogen atom in the structural unit represented by the general formula (1) and / or the general formula (2). Preferably there is.

In the present invention, the hydrolyzable silyl group is a silicon-containing group having a hydrolyzable group directly bonded to a silicon atom, and specifically includes, for example, a group represented by the general formula (4). .

(In the general formula (4), R ⁵ is a monovalent organic group such as an alkyl group, an aryl group or an aralkyl group, and R ⁶ is a halogen atom, an alkoxy group, an acyloxy group, a phenoxy group, an aryloxy group, a mercapto group, A hydrolyzable group selected from the group consisting of an amino group, an amide group, an aminooxy group, an iminooxy group, and an alkenyloxy group, and b is an integer of 0 to 2.)

Examples of the alkyl group in R ⁵ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a tert group. -Pentyl group, 1-methylbutyl group, 2-methylbutyl group, 1,2-dimethylpropyl group, 1-ethylpropyl group, hexyl group, isohexyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl Group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 2,2-dimethylbutyl group, 1-ethylbutyl group, 1,1,2-trimethylpropyl group, 1,2,2-trimethylpropyl group 1-ethyl-2-methylpropyl group, 1-ethyl-1-methylpropyl group and the like.
Examples of the group include a phenyl group, a naphthyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 4-vinylphenyl group, and a 3-isopropylphenyl group.
Examples of the aralkyl group include a benzyl group, a diphenylmethyl group, and a naphthylmethyl group.

In R ⁶ , examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, and a sec-butoxy group.
Examples of the acyloxy group include formyloxy group, acetoxy group, propanoyloxy group, butanoyloxy group, pivaloyloxy group, pentanoyloxy group, phenylacetoxy group, acetoacetoxy group, benzoyloxy group, naphthoyloxy group, etc. Is mentioned.
Examples of the aryloxy group include a phenyloxy group and a naphthyloxy group.
Examples of the alkenyloxy group include vinyloxy group, allyloxy group, 1-propenyloxy group, isopropenyloxy group, 2-butenyloxy group, 3-butenyloxy group, 2-petenyloxy group, 3-methyl-3-butenyloxy group, 2 -Hexenyloxy group and the like.

By hydrolyzing the hydrolyzable group represented by R ⁶ , the hydrolyzable silyl group represented by the general formula (4) becomes a silanol group. Among these, a methoxy group and an ethoxy group are preferable because of excellent hydrolyzability.
The hydrolyzable silyl group specifically includes an oxygen atom having a bond in the structural unit represented by the general formula (1) and / or the general formula (2) bonded to the hydrolyzable group. Or it is preferable that it is the hydrolyzable silyl group substituted.

Since the silanol group or the hydrolyzable silyl group undergoes a hydrolytic condensation reaction between the hydroxyl group in the silanol group or the hydrolyzable group in the hydrolyzable silyl group, the polysiloxane structure of the resulting coating film The crosslink density increases, and a coating film excellent in solvent resistance can be formed.
Further, the polysiloxane segment (a1) containing the silanol group or the hydrolyzable silyl group is bonded to the vinyl polymer segment (a2) described later via the bond represented by the general formula (3). Use when.

In addition, examples of the structure in which at least one of R ¹ , R ^2, and R ³ is a group having the polymerizable double bond as the polysiloxane segment (a1) include the following structures.

In the present invention, it is important that the mass ratio of the polysiloxane segment (a1) in the solid content of the composite resin (A) is 20 to 70% by mass, whereby the curable resin composition has a normal temperature. It becomes possible to achieve both curability and weather resistance.

(Composite resin (A) vinyl polymer segment (a2))
The vinyl polymer segment (a2) in the present invention is a vinyl polymer segment such as an acrylic polymer, a fluoroolefin polymer, a vinyl ester polymer, an aromatic vinyl polymer, and a polyolefin polymer. . These are preferably selected appropriately depending on the application.

The acrylic polymerizable segment is obtained by polymerizing or copolymerizing a general-purpose (meth) acrylic monomer. The (meth) acrylic monomer is not particularly limited, and vinyl monomers can also be copolymerized. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) Alkyl (meth) acrylates having an alkyl group having 1 to 22 carbon atoms such as acrylate and lauryl (meth) acrylate; aralkyl (meth) acrylates such as benzyl (meth) acrylate and 2-phenylethyl (meth) acrylate Cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate; ω-alkoxyalkyl such as 2-methoxyethyl (meth) acrylate and 4-methoxybutyl (meth) acrylate ( ) Acrylates; vinyl acetate, carboxylic acid vinyl esters such as vinyl propionate, vinyl pivalate and vinyl benzoate; alkyl esters of crotonic acid such as methyl crotonate and ethyl crotonate; dimethyl malate, di-n -Dialkyl esters of unsaturated dibasic acids such as butyl malate, dimethyl fumarate and dimethyl itaconate; α-olefins such as ethylene and propylene; vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, etc. Fluoroolefins; alkyl vinyl ethers such as ethyl vinyl ether and n-butyl vinyl ether; cycloalkyl vinyl ethers such as cyclopentyl vinyl ether and cyclohexyl vinyl ether; N, N-dimethyl (meth) Acrylamide, N- (meth) acryloyl morpholine, N- (meth) acryloyl pyrrolidine, tertiary amide group-containing monomers such as N- vinylpyrrolidone and the like.

There is no particular limitation on the polymerization method, the solvent, or the polymerization initiator for copolymerizing the monomers, and the vinyl polymer segment (a2) can be obtained by a known method. For example, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-) can be obtained by various polymerization methods such as bulk radical polymerization, solution radical polymerization, and non-aqueous dispersion radical polymerization. Dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), tert-butylperoxypivalate, tert-butylperoxybenzoate, tert-butylperoxy-2-ethylhexanoate, di- The vinyl polymer segment (a2) can be obtained by using a polymerization initiator such as tert-butyl peroxide, cumene hydroperoxide, diisopropyl peroxycarbonate or the like.

The number average molecular weight of the vinyl polymer segment (a2) is preferably in the range of 500 to 200,000 in terms of number average molecular weight (hereinafter abbreviated as “Mn”). It is possible to prevent thickening and gelation during the production of A) and is excellent in durability. In particular, Mn is more preferably in the range of 700 to 100,000, and more preferably in the range of 1,000 to 50,000, because a good film can be formed when a layer is formed on the substrate.

In addition, the vinyl polymer segment (a2) is a vinyl polymer segment (A1) in order to form a composite resin (A) bonded to the polysiloxane segment (a1) by a bond represented by the general formula (3). It has a silanol group and / or a hydrolyzable silyl group directly bonded to the carbon atom in a2). Since these silanol groups and / or hydrolyzable silyl groups become bonds represented by the general formula (3) in the production of the composite resin (A) described later, the composite resin ( Almost no vinyl polymer segment (a2) in A). However, there is no problem even if silanol groups and / or hydrolyzable silyl groups remain in the vinyl polymer segment (a2), and when the coating film is formed by the curing reaction of the group having a polymerizable double bond. In parallel with the curing reaction, a hydrolysis condensation reaction proceeds between the hydroxyl group in the silanol group or the hydrolyzable group in the hydrolyzable silyl group, so that the crosslink density of the polysiloxane structure of the resulting coating film And a coating film excellent in solvent resistance can be formed.

Specifically, the vinyl polymer segment (a2) having a silanol group and / or a hydrolyzable silyl group directly bonded to a carbon atom includes the general-purpose monomer, the silanol group directly bonded to the carbon bond, and / or It is obtained by copolymerizing a vinyl monomer containing a hydrolyzable silyl group.
Examples of vinyl monomers containing a silanol group and / or a hydrolyzable silyl group directly bonded to a carbon atom include vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyltri (2-methoxyethoxy) silane. , Vinyltriacetoxysilane, vinyltrichlorosilane, 2-trimethoxysilylethyl vinyl ether, 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 3- (meth) acryloyloxypropyl Examples include methyldimethoxysilane and 3- (meth) acryloyloxypropyltrichlorosilane. Among these, vinyltrimethoxysilane and 3- (meth) acryloyloxypropyltrimethoxysilane are preferable because the hydrolysis reaction can easily proceed and by-products after the reaction can be easily removed.

(Hydroxyl value of vinyl polymer segment (a2))
Moreover, in order to cure the curable resin composition containing the composite resin (A) and the polyisocyanate (B), the vinyl polymer segment (a2) contains an alcoholic hydroxyl group. It is important that the hydroxyl group value of the vinyl polymer segment (a2) is 55 to 200 mgKOH / g because it reacts with the polyisocyanate (B) and cures at room temperature, preferably in the range of 90 to 200 mgKOH / g. . When the hydroxyl value is less than 55 mgKOH / g, it is difficult to react with the polyisocyanate (B), so it does not cure at room temperature, and when the hydroxyl value is more than 200 mgKOH / g, gelation occurs when the composite resin (A) is synthesized. Is not preferable.

The vinyl polymer segment (a2) having an alcoholic hydroxyl group can be obtained by copolymerizing a (meth) acryl monomer having an alcohol hydroxyl group. Specific examples of the (meth) acrylic monomer having an alcohol hydroxyl group 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, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl mono Butyl fumarate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, “Placcel FM” or “Placcel FA” (both caprolactone addition monomers manufactured by Daicel Chemical Industries, Ltd.) Various alpha, beta-hydroxyalkyl esters of ethylenically unsaturated carboxylic acid or an adduct thereof with ε- caprolactone, and the like.
Of these, 2-hydroxyethyl (meth) acrylate is preferable because of its easy reaction.

(Production method of composite resin (A))
Specifically, the composite resin (A) used in the present invention is produced by the methods shown in the following (Method 1) to (Method 3).

(Method 1) The general-purpose (meth) acrylic monomer and the like, and a vinyl monomer containing a silanol group and / or a hydrolyzable silyl group directly bonded to the carbon bond are copolymerized and directly bonded to the carbon bond. A vinyl polymer segment (a2) containing a silanol group and / or a hydrolyzable silyl group is obtained. This and a silane compound are mixed and hydrolytic condensation reaction is carried out. At this time, an epoxy group-containing silane compound having both a silanol group and / or a hydrolyzable silyl group is simultaneously used in order to introduce an epoxy group into the resulting polysiloxane. In addition, when there are other groups to be introduced, a silane compound having the group to be introduced is used in combination. For example, when a group is introduced, a silane compound having both a group and a silanol group and / or a hydrolyzable silyl group may be appropriately used in combination. When a group having a polymerizable double bond is introduced, a silane compound having both a group having a polymerizable double bond and a silanol group and / or a hydrolyzable silyl group may be used in combination.
In the method, the silanol group or hydrolyzable silyl group of the silane compound and the silanol group contained in the vinyl polymer segment (a2) containing the silanol group and / or hydrolyzable silyl group directly bonded to the carbon bond and And / or a hydrolytic condensation reaction with a hydrolyzable silyl group to form a polysiloxane segment (a1) having the epoxy group, a polysiloxane segment (a1) having the epoxy group, and a vinyl polymer segment. A composite resin (A) in which (a2) is combined with the bond represented by the general formula (3) is obtained.

(Method 2) In the same manner as in Method 1, a vinyl polymer segment (a2) containing a silanol group and / or a hydrolyzable silyl group directly bonded to a carbon bond is obtained.
On the other hand, a silane compound (in order to introduce an epoxy group, an epoxy group-containing silane compound having both a silanol group and / or a hydrolyzable silyl group is used. If there is another group to be introduced, the group to be introduced is selected. The polysiloxane segment (a1) having an epoxy group is obtained by hydrolytic condensation reaction. Then, the silanol group and / or hydrolyzable silyl group of the vinyl polymer segment (a2) and the silanol group and / or hydrolyzable silyl group of the polysiloxane segment (a1) having an epoxy group are hydrolyzed. A decomposition condensation reaction is performed.

(Method 3) In the same manner as in Method 1, a vinyl polymer segment (a2) containing a silanol group and / or a hydrolyzable silyl group directly bonded to a carbon bond is obtained. On the other hand, the polysiloxane segment (a1) which may or may not have an epoxy group is obtained in the same manner as in Method 2. Furthermore, in order to introduce an epoxy group into the polysiloxane segment (a1), when there is an epoxy group-containing silane compound having both a silanol group and / or a hydrolyzable silyl group and a group to be introduced, If necessary, a silane compound having a group to be introduced is mixed and subjected to a hydrolysis condensation reaction.

In addition, as a silane compound having both a group having a polymerizable double bond and a silanol group and / or a hydrolyzable silyl group used when introducing a group having a polymerizable double bond, for example, vinyltrimethoxy Silane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinyltri (2-methoxyethoxy) silane, vinyltriacetoxysilane, vinyltrichlorosilane, 2-trimethoxysilylethyl vinyl ether, 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane, 3- (meth) acryloyloxypropyltrichlorosilane, etc. are used in combination. Among these, vinyltrimethoxysilane and 3- (meth) acryloyloxypropyltrimethoxysilane are preferable because the hydrolysis reaction can easily proceed and by-products after the reaction can be easily removed.

Other general-purpose silane compounds used in the (Method 1) to (Method 3) include, for example, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-butoxysilane, ethyltrimethoxysilane, n- Various nolganotrialkoxysilanes such as propyltrimethoxysilane, iso-butyltrimethoxysilane, cyclohexyltrimethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-butoxysilane, diethyldimethoxysilane, methylcyclohexyldimethoxysilane Or various diorganodialkoxysilanes such as methyltrichlorosilane, ethyltrichlorosilane, vinyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane or the like Roroshiran acids and the like. Of these, organotrialkoxysilanes and diorganodialkoxysilanes that can easily undergo a hydrolysis reaction and easily remove by-products after the reaction are preferable.

Further, a tetrafunctional alkoxysilane compound such as tetramethoxysilane, tetraethoxysilane or tetra n-propoxysilane or a partial hydrolysis condensate of the tetrafunctional alkoxysilane compound may be used in combination as long as the effects of the present invention are not impaired. it can. When the tetrafunctional alkoxysilane compound or a partially hydrolyzed condensate thereof is used in combination, the silicon atoms of the tetrafunctional alkoxysilane compound are 20 with respect to the total silicon atoms constituting the polysiloxane segment (a1). It is preferable to use together so that it may become the range which does not exceed mol%.

In addition, a metal alkoxide compound other than a silicon atom such as boron, titanium, zirconium, or aluminum can be used in combination with the silane compound as long as the effects of the present invention are not impaired. For example, it is preferable to use the metal alkoxide compound in combination within a range not exceeding 25 mol% with respect to all silicon atoms constituting the polysiloxane segment (a1).

In the hydrolysis condensation reaction in the (Method 1) to (Method 3), a part of the hydrolyzable group is hydrolyzed under the influence of water or the like to form a hydroxyl group, and then the hydroxyl groups or the hydroxyl group and the hydrolysis group are hydrolyzed. This refers to a proceeding condensation reaction that proceeds with a functional group. The hydrolysis-condensation reaction can be performed by a known method, but a method in which the reaction is advanced by supplying water and a catalyst in the production process is simple and preferable.

Examples of the catalyst used include inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid; organic acids such as p-toluenesulfonic acid, monoisopropyl phosphate and acetic acid; inorganic bases such as sodium hydroxide and potassium hydroxide; tetraisopropyl titanate , Titanic acid esters such as tetrabutyl titanate; 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), 1,5-diazabicyclo [4.3.0] nonene-5 (DBN), 1 Compounds containing various basic nitrogen atoms such as 1,4-diazabicyclo [2.2.2] octane (DABCO), tri-n-butylamine, dimethylbenzylamine, monoethanolamine, imidazole, 1-methylimidazole; Tetramethylammonium salt, tetrabutylammonium salt, dilauryldimethylammoni Various quaternary ammonium salts such as chlorinated salts, which have chloride, bromide, carboxylate or hydroxide as counter anions; dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin Examples thereof include tin carboxylates such as diacetylacetonate, tin octylate and tin stearate. A catalyst may be used independently and may be used together 2 or more types.

The addition amount of the catalyst is not particularly limited, but generally it is preferably used in the range of 0.0001 to 10% by mass with respect to the total amount of each compound having the silanol group or hydrolyzable silyl group. , More preferably in the range of 0.0005 to 3% by mass, and particularly preferably in the range of 0.001 to 1% by mass.

The amount of water to be supplied is preferably 0.05 mol or more with respect to 1 mol of the silanol group or hydrolyzable silyl group of each compound having the silanol group or hydrolyzable silyl group, The above is more preferable, and particularly preferably 0.5 mol or more.
These catalyst and water may be supplied collectively or sequentially, or may be supplied by previously mixing the catalyst and water.

The reaction temperature for carrying out the hydrolysis condensation reaction in the above (Method 1) to (Method 3) is suitably in the range of 0 ° C. to 150 ° C., and preferably in the range of 20 ° C. to 100 ° C. The reaction can be carried out under any conditions of normal pressure, increased pressure, or reduced pressure. Moreover, you may remove the alcohol and water which are the by-products which can be produced | generated in the said hydrolysis-condensation reaction by methods, such as distillation, as needed.

The charging ratio of each compound in the above (Method 1) to (Method 3) is appropriately selected depending on the desired structure of the composite resin (A) used in the present invention. Among them, since the durability of the obtained coating film is excellent, it is important to obtain the composite resin (A) so that the content of the polysiloxane segment (a1) is 20 to 70% by mass, and 30 to 70% by mass. Is preferred.

In the above (Method 1) to (Method 3), as a specific method for combining the polysiloxane segment and the vinyl polymer segment in a block shape, the silanol group and the above-described silanol group may be added to only one or both ends of the polymer chain. For example, in the case of (Method 1), a silane compound is mixed with the vinyl polymer segment, and a hydrolyzable silyl group-containing vinyl polymer segment is used as an intermediate. The method of carrying out decomposition condensation reaction is mentioned.

On the other hand, in the above (Method 1) to (Method 3), as a specific method of complexing the polysiloxane segment with the vinyl polymer segment in a graft form, the main chain of the vinyl polymer segment is The vinyl polymer segment having a structure in which silanol groups and / or hydrolyzable silyl groups are randomly distributed is used as an intermediate. For example, in the case of (Method 2), the vinyl polymer segment is Examples thereof include a method of subjecting the silanol group and / or hydrolyzable silyl group and the silane compound to a hydrolytic condensation reaction.

(Polyisocyanate (B))
The curable resin composition in the present invention contains the composite resin (A) and the polyisocyanate (B). At this time, it is important that the hydroxyl value of the vinyl polymer segment (a2) constituting the composite resin (A) is 55 to 200 mgKOH / g. Further, it is important that the mass ratio of the polyisocyanate (B) is 5 to 50% by mass in the total solid content of the curable resin composition of the present invention. By containing the polyisocyanate in this range, a coating film having particularly excellent long-term weather resistance (specifically, crack resistance) outdoors can be obtained. This is because a polyisocyanate and a hydroxyl group in the system (this is a hydroxyl group in an active energy ray-curable monomer having a hydroxyl group of the vinyl polymer segment (a2) or an alcoholic hydroxyl group described later). It is presumed that a urethane bond, which is a soft segment, is formed and functions to relieve stress concentration due to curing derived from a polymerizable double bond.

The polyisocyanate (B) to be used is not particularly limited and known ones can be used, but aromatic diisocyanates such as tolylene diisocyanate and diphenylmethane-4,4′-diisocyanate, meta-xylylene diisocyanate, Polyisocyanates mainly composed of aralkyl diisocyanates such as α, α, α ', α'-tetramethyl-meta-xylylene diisocyanate have the problem that the cured coating film yellows when exposed to long-term outdoor exposure. It is preferable to minimize the amount used.

From the viewpoint of long-term outdoor use, the polyisocyanate (B) used in the present invention is preferably an aliphatic polyisocyanate containing an aliphatic diisocyanate as a main raw material. Examples of the aliphatic diisocyanate include tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (hereinafter abbreviated as “HDI”), 2,2,4- (or 2,4,4). Trimethyl-1,6-hexamethylene diisocyanate, lysine isocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,4-diisocyanate cyclohexane, 1,3-bis (diisocyanate methyl) cyclohexane, 4,4 '-Dicyclohexylmethane diisocyanate, etc. Among them, HDI is particularly suitable from the viewpoint of crack resistance and cost.

Examples of the aliphatic polyisocyanate obtained from the aliphatic diisocyanate include allophanate type polyisocyanate, biuret type polyisocyanate, adduct type polyisocyanate, and isocyanurate type polyisocyanate, and any of them can be suitably used.

In addition, as the above-described polyisocyanate, so-called blocked polyisocyanate compounds blocked with various blocking agents can be used. Examples of the blocking agent include alcohols such as methanol, ethanol and lactic acid esters; phenolic hydroxyl group-containing compounds such as phenol and salicylic acid esters; amides such as ε-caprolactam and 2-pyrrolidone; oximes such as acetone oxime and methyl ethyl ketoxime Active methylene compounds such as methyl acetoacetate, ethyl acetoacetate and acetylacetone can be used.

The above-mentioned various polyisocyanates may be used alone or in combination.

The isocyanate group in the polyisocyanate is preferably 5 to 50% by mass from the viewpoint of crack resistance of a cured coating film obtained when used as a paint. When the isocyanate group in the polyisocyanate exceeds 50%, the molecular weight of the polyisocyanate becomes small, and crack resistance due to stress relaxation may not be exhibited. The reaction between the polyisocyanate and a hydroxyl group in the system (this is a hydroxyl group in the active energy ray-curable monomer having a hydroxyl group of the vinyl polymer segment (a2) or an alcoholic hydroxyl group described later), in particular, There is no need for heating, etc., and the reaction proceeds gradually by leaving it at room temperature. If necessary, the reaction between the alcoholic hydroxyl group and the isocyanate may be promoted by heating at 80 ° C. for several minutes to several hours (20 minutes to 4 hours). In that case, you may use a well-known urethanation catalyst as needed. The urethanization catalyst is appropriately selected according to the desired reaction temperature.

(Long-term storage stability and curability and high weather resistance)
In the curable resin composition of the present invention, the mass ratio of the polysiloxane segment (a1) in the solid content of the composite resin (A) is 20 to 70% by mass, and the solid content of the composite resin (A) is The epoxy equivalent is 900 to 17000 g / eq, the hydroxyl value of the vinyl polymer segment (a2) is 55 to 200 mgKOH / g, and the mass ratio of the polyisocyanate (B) is 5 to 50 in the total solid content. When it is% by mass, the storage stability of only the composite resin (A) before curing in the state of one liquid, and the two liquids of the composite resin (A) and the polyisocyanate (B) as a curing agent are mixed. It is possible to provide a resin that is compatible with later room temperature curability and is transparent and excellent in weather resistance.

The long-term storage stability of the composite resin (A) in the state of one liquid before curing is considered to be a result of the epoxy group suppressing the condensation reaction between silanol groups. As the mechanism, it is thought that the presence of epoxy groups in the polysiloxane captures silanol residues located nearby by protonated epoxy groups under acidic conditions and prevents their condensation. .

In addition, when the epoxy equivalent of the solid content of the composite resin (A) is less than 900 g / eq, the effect of suppressing the condensation reaction between silanol groups by the epoxy group-containing silane compound becomes too large, so long-term storage before curing. Although stability is maintained, the progress of crosslinking after film formation becomes insufficient, and the cured film does not have sufficiently high weather resistance. On the other hand, when the epoxy equivalent of the solid content is larger than 17000 g / eq, the effect of suppressing the condensation reaction between silanol groups by the epoxy group-containing silane compound is too small, and thus long-term storage stability before curing is not maintained. .

Moreover, when the hydroxyl value of the vinyl polymer segment (a2) is smaller than 55 mgKOH / g, the crosslinking density when the cured film is formed becomes insufficient, and the cured film has sufficiently high curability and high cured film. Does not have weather resistance. On the other hand, when the hydroxyl value of the vinyl polymer segment (a2) is larger than 200 mgKOH / g, gelation occurs during the polymerization of the vinyl polymer segment (a2), and a composite resin cannot be obtained.

From the above, when the epoxy equivalent of the solid content is in the range of 900 to 17000 g / eq, the effect of suppressing the condensation reaction between silanol groups by the epoxy group-containing silane compound and the progress of the crosslinking reaction when a cured film is formed. Since the balance is optimized, long-term storage stability before curing, a certain level of curability and high weather resistance of the cured film can be obtained. Similarly, when the hydroxyl group value of the vinyl polymer segment (a2) is in the range of 55 to 200 mgKOH / g, the crosslinked density when the cured film is formed is sufficient, and the cured film has sufficiently high curability and curing. The film has high weather resistance.

(Curing method)
Since the curable resin composition of the present invention can be cured at room temperature by mixing the composite resin (A) and the polyisocyanate (B), it is preferably about 5 to 10 days at room temperature, more preferably 7 A cured film having high practicality can be obtained by allowing it to stand for about 10 days to dry.

Alternatively, when faster curing is desired, a highly practical cured film can be obtained by performing baking within a temperature range of about 80 to 250 ° C. for about 30 seconds to 2 hours. Is possible. In this case, depending on the baking conditions, it is also possible to obtain a cured film having higher hardness, higher gel fraction, and higher weather resistance than the room temperature cured film.

(Other compounds)
The curable resin composition of the present invention may use a dispersion medium for the purpose of adjusting the solid content and viscosity of the dispersion. Any liquid medium that does not impair the effects of the present invention may be used, and examples thereof include the above organic solvents and liquid organic polymers.

The curable composition of the present invention can be cured at room temperature, but various catalysts may be added to perform thermal curing. It is preferable to select each catalyst in consideration of the reaction temperature, reaction time, etc. of the urethanization reaction between an alcoholic hydroxyl group and an isocyanate.
Moreover, it is also possible to use a thermosetting resin together. Examples of the thermosetting resin include vinyl resins, unsaturated polyester resins, polyurethane resins, epoxy resins, epoxy ester resins, acrylic resins, phenol resins, petroleum resins, ketone resins, silicon resins, and modified resins thereof.

In addition, inorganic pigments, organic pigments, extender pigments, clay minerals, waxes, surfactants, stabilizers, flow regulators, dyes, leveling agents, rheology control agents, UV absorbers, antioxidants, or as necessary Various additives such as a plasticizer can also be used.

(Paint and base material)
The curable resin composition of the present invention can be used as it is as a curable coating. Moreover, you may add additives, such as an above described organic pigment and an inorganic pigment.

The film thickness of the coating film formed using the curable resin composition or paint of the present invention is not particularly limited, but from the viewpoint that a cured coating film having long-term weather resistance outdoors can be formed, It is preferably 0.1 to 300 μm. When the thickness of the cured coating film is less than 0.1 μm, discoloration of the plastic material and generation of cracks cannot be prevented, and when the film thickness exceeds 300 μm, the volatilization of the solvent does not proceed completely, and Care should be taken because residual solvent will remain in the film, which may cause poor curing.

As the base material, various materials can be used. For example, a metal base material, an inorganic base material, a plastic base material, paper, a woody base material and the like can be used.

Examples of the inorganic base material include glass, concrete, gypsum board, asphalt, and the like, and can be suitably used as a paint for building / civil engineering materials.

Examples of the plastic substrate include polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyesters such as polyethylene isophthalate, polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; nylon 1, nylon 11, and nylon 6, Polyamides such as nylon 66, nylon MX-D; styrene polymers such as polystyrene, styrene-butadiene block copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer (ABS resin); Acrylic polymers such as polymethyl methacrylate and methyl methacrylate / ethyl acrylate copolymer; polycarbonate and the like can be used. The plastic substrate may have a single layer or a laminated structure of two or more layers. Moreover, these plastic base materials may be unstretched, uniaxially stretched, or biaxially stretched.

The plastic substrate may be subjected to a known surface treatment on the surface of the substrate in order to further improve the adhesion with the paint of the present invention. Examples of such a surface treatment include corona discharge treatment, plasma, and the like. Examples thereof include a process, a flame plasma process, an electron beam irradiation process, and an ultraviolet irradiation process, and a process combining one or more of these may be performed.

(Coating and curing on base material)
For example, when a layer formed of the paint is laminated on the substrate surface, there is no particular limitation, but a normal coating method is used. Specifically, the composite resin (A), the polyisocyanate (B), and various additives are mixed to prepare a paint containing a curable composition, and after applying the paint on the substrate surface, The cured product having excellent weather resistance can be obtained by allowing to stand and drying for about 7 to 10 days.

In this case, in order to control the rheology, it is preferable that the curable composition and the coating material be used by appropriately diluting the solvent by adding a solvent in addition to the additive. The solvent is not particularly limited, but it is preferable to avoid the use of aromatic hydrocarbons such as toluene and xylene in consideration of the working environment during construction.

The film thickness after coating is not particularly limited, but is preferably 0.1 to 300 μm from the viewpoint that a cured coating film having long-term weather resistance outdoors can be formed. When the film thickness of the cured coating film is less than 0.1 μm, discoloration and cracking of the plastic material cannot be prevented, and when the film thickness exceeds 300 μm, the volatilization of the solvent does not proceed completely, Care should be taken because residual solvent will remain in the coating film, which may cause poor curing.

In addition, the above-described base material may be a known antistatic agent, antifogging agent, antiblocking agent, ultraviolet absorber, antioxidant, light stabilizer, crystal, and the like, as long as the effects of the present invention are not impaired. Known additives such as nucleating agents and lubricants may be contained.

The shape of the base material is not particularly limited, and may be, for example, a sheet shape, a plate shape, a spherical shape, a film shape, or a large structure, or an assembly or molded product having a complicated shape. Further, the surface of the base material may be previously coated with an undercoat paint or the like, and even if the coated portion is deteriorated, the paint of the present invention can be applied.

As the undercoat paint, known water-soluble or water-dispersed paints, organic solvent-type or organic solvent-dispersed paints, powder paints, and the like can be used. Specifically, acrylic resin-based paint, polyester resin-based paint, alkyd resin-based paint, epoxy resin-based paint, fatty acid-modified epoxy resin-based paint, silicon resin-based paint, polyurethane resin-based paint, fluoroolefin-based paint, or amine-modified epoxy resin Various types such as resin paints can be used. The undercoat paint may be a clear paint containing no pigment, or an enamel paint containing the pigment or a metallic paint containing aluminum flakes.

Examples of the method for applying the paint of the present invention to the substrate include a brush coating method, a roller coating method, a spray coating method, a dip coating method, a flow coater coating method, a roll coater coating method or an electrodeposition coating method. It is possible to apply a known and commonly used coating method.

An article having a cured coating film having excellent long-term weather resistance outdoors by applying the paint of the present invention to the surface of the substrate by the coating method and then allowing it to stand at room temperature for about 7 to 10 days to dry. Can be obtained.

(Goods)
Examples of articles that can be coated with the paint of the present invention include housings for home appliances such as televisions, refrigerators, washing machines, and air conditioners; housings for electronic devices such as personal computers, smartphones, mobile phones, digital cameras, and game machines. Body: Housing for OA equipment such as printers, facsimiles, etc .; Various plastic parts such as various parts used for interior materials of various vehicles such as automobiles and railway vehicles; Woodwork materials such as furniture, artificial and synthetic leather; FRP bathtubs It is done. Interior and exterior materials for buildings such as exterior walls, roofs, glass, and decorative panels; civil engineering members such as soundproof walls and drainage grooves; galvanized steel sheets used for household appliances, industrial machinery, automotive parts, and aluminum-zinc Metal members such as plated steel plates such as alloy steel plates, aluminum plates, aluminum alloy plates, electromagnetic steel plates, copper plates, and stainless steel plates are also included.

Next, the present invention will be specifically described with reference to examples and comparative examples.

(Synthesis Example 1: Synthesis of polysiloxane (a-1-1))
In a reaction vessel equipped with a stirrer, thermometer, dropping funnel, condenser and nitrogen gas inlet, methyltrimethoxysilane (hereinafter abbreviated as “MTMS”) 1417.0 parts by mass, γ-glycidoxy 83.0 parts of propyltrimethoxysilane (hereinafter abbreviated as “GPTMS”) were charged, and the temperature was raised to 60 ° C. while stirring under aeration of nitrogen gas. Next, a mixture of 0.20 part of “Phoslex A-4” (normal butyl acid phosphate manufactured by Sakai Chemical Co., Ltd.) and 211.1 parts of deionized water was added dropwise over 5 minutes. After completion of the dropwise addition, the reaction vessel was heated to 80 ° C. and stirred for 4 hours to carry out a hydrolysis condensation reaction, thereby obtaining a reaction product. By removing methanol and water contained in the obtained reaction product under a reduced pressure of 1 to 30 kilopascals (kPa) at 60 ° C., the number average molecular weight is 1000 and the active ingredient is 75.2. % Polysiloxane (a-1-1) 1000 parts was obtained.

The “active ingredient” is a value obtained by dividing the theoretical yield (parts by mass) when all the methoxy groups of the silane monomer used undergo hydrolysis condensation reaction by the actual yield (parts by mass) after hydrolysis condensation reaction, That is, it is calculated by the formula (theoretical yield when all the methoxy groups of the silane monomer undergo hydrolysis hydrolysis reaction (mass part) / actual yield after hydrolysis condensation reaction (mass part)).

The number average molecular weight was calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC). However, Shodex GPC SYSTEM-21 (manufactured by Showa Denko KK) is used as the apparatus, Shodex Asahipak GF-7M HQ (manufactured by Showa Denko KK) is used as the GPC column, and 20 mM LiBr dimethylformamide solution is used as the GPC solvent It was.

(Synthesis Examples 2 to 7: Synthesis of polysiloxanes (a-1-2) to (a-1-7))
1000 parts of polysiloxanes (a-1-2) to (a-1-7) were obtained in the same manner as in Synthesis Example 1 except that the composition was changed to the composition shown in Table 1 below.

Table 1 shows the compositions and properties of the polysiloxanes (a-1-1) to (a-1-7) obtained above.

GPDMMS: γ-glycidoxypropylmethyldimethoxysilane EpCHETMS: β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane

(Synthesis Example 8: Synthesis of vinyl polymer (a-2-1))
In the same reaction vessel as in Synthesis Example 1, 23.2 parts of phenyltrimethoxysilane (hereinafter abbreviated as “PTMS”), 28.0 parts of dimethyldimethoxysilane (hereinafter abbreviated as “DMDMS”), n-acetate -348.8 parts of butyl was added as an initial solvent, and the temperature was raised to 95 ° C while stirring under aeration of nitrogen gas. Next, as a monomer, methyl methacrylate (hereinafter abbreviated as “MMA”) 125.2 parts, n-butyl methacrylate (hereinafter abbreviated as “BMA”) 74.4 parts, n-butyl acrylate (hereinafter abbreviated as “MMA”) 91.6 parts, methacrylic acid (hereinafter abbreviated as “MAA”) 4.0 parts, 3-methacryloyloxypropyltrimethoxysilane (hereinafter abbreviated as “MPTMS”) 12.0 parts, 2-hydroxyethyl methacrylate (hereinafter abbreviated as “HEMA”) 92.8 parts, n-butyl acetate 40.0 parts, tert-butylperoxy-2-ethylhexanoate (hereinafter referred to as “HEMA”) Abbreviated as “TBPOEH”.) 30.0 parts were mixed and kept at 95 ° C. with stirring under aeration of nitrogen gas for 4 hours. In was dropped. After further stirring for 2 hours at the same temperature, a mixture of 0.064 part of “Phoslex A-4” and 14.6 parts of deionized water was added dropwise to the reaction vessel over 5 minutes, and the mixture was stirred at the same temperature for 4 hours. By stirring for a period of time, hydrolysis condensation reaction of PTMS, DMDMS and MPTMS was advanced to obtain 884 parts of a vinyl polymer (a-2-1). When the vinyl polymer (a-2-1) was analyzed by ¹ H-NMR, almost 100% of the trimethoxysilyl group of the silane monomer in the reaction vessel was hydrolyzed.

The hydroxyl value of the vinyl polymer segment of the reaction product was estimated to be 100 mgKOH / g from the content of HEMA with respect to the total amount of monomers used.

(Synthesis Examples 9 to 11: Synthesis of vinyl polymers (a-2-2) to (a-2-4))
Vinyl polymers (a-2-2) to (a-2-4) were obtained in the same manner as in Synthesis Example 8 except that the composition was changed to the composition shown in Table 2 below.

(Synthesis Example 12: Synthesis of vinyl polymer (a-2-5))
A reaction vessel similar to Synthesis Example 1 was charged with 22.8 parts of PTMS, 27.6 parts of DMDMS, and 345.6 parts of n-butyl acetate, and the temperature was raised to 95 ° C. while stirring under nitrogen gas. . MMA 67.2 parts, BMA 76.8 parts, 2-ethylhexyl methacrylate (2-EHMA) 31.6 parts, BA 4.0 parts, MAA 4.0 parts, MPTMS 12.0 parts, HEMA 204.4 A mixture containing 40.0 parts of n-butyl acetate and 30.0 parts of TBPOEH was dropped into the reaction vessel over 4 hours at the same temperature while stirring under a stream of nitrogen gas. When the mixture was stirred at the same temperature for 1 hour, the viscosity of the reaction solution increased rapidly and gelled within a few minutes.

The hydroxyl value of the vinyl polymer segment of the reaction product that resulted in gelation was estimated to be 220 mgKOH / g from the content of HEMA with respect to the total amount of monomers used. *

Table 2 shows the composition and property values of the vinyl polymers (a-2-1) to (a-2-5) obtained above.

2-EHMA: 2-ethylhexyl methacrylate

(Synthesis Example 13: Synthesis of Composite Resin (A-1))
In the same reaction vessel as in Synthesis Example 1, 512.4 parts of the vinyl polymer (a-2-1) obtained in Synthesis Example 8 and the polysiloxane (a-1-1) obtained in Synthesis Example 1 were used. 107.0 parts was charged and stirred for 5 minutes, 34.9 parts of deionized water was added, and the mixture was stirred at 80 ° C. for 4 hours. The vinyl polymer (a-2-1) and the polysiloxane (a The hydrolysis-condensation reaction of 1-1-1) was performed. The obtained reaction product was distilled under a reduced pressure of 1 to 30 kPa at 60 ° C. for 2 hours to remove the produced methanol and water, and then propylene glycol monomethyl ether acetate (hereinafter “PGMAC”). 40.5 parts, n-butyl acetate 143.3 parts is added, and composite resin (A-1) 600 parts having a polysiloxane segment and a vinyl polymer segment having a nonvolatile content of 55.1% Got.

The epoxy equivalent (the molecular weight (g / eq) of the sample per epoxy group) of the obtained composite resin (A-1) was measured according to the following procedure in accordance with JIS K7236. First, a 5.0 g sample was weighed in a 100 cc beaker, and 10 ml of chloroform was added and dissolved by stirring. Thereafter, 20 ml of acetic acid and 10 ml of tetraammonium bromide acetic acid solution were added at room temperature, and about 2-3 drops of crystal violet was used as an indicator with an automatic titrator AUT-701 (manufactured by Toa DKK Corporation). By titrating a 1 mol / L perchloric acid / acetic acid solution (N / 10), the equivalence point is automatically determined, and the epoxy equivalent (from the titration difference between the sample and blank test and the potential change) The calculated value of g / eq) was obtained. Here, the tetraammonium bromide acetic acid solution was prepared by dissolving 100 g of tetraammonium bromide in 400 ml of acetic acid. This revealed that the epoxy equivalent of the solid content of the composite resin (A-1) was 8800 g / eq.

The hydroxyl value of the vinyl polymer segment (a-2-1) in the obtained composite resin (A-1) was measured by the following procedure. First, 2.5 g of the composite resin (A-1) was weighed into a 200 ml Meyer flask, and an acetylating agent obtained by mixing acetic anhydride and pyridine at a volume ratio of 1:19 was added with a whole pipette. Next, it was placed in a heating bath with a condenser tube adjusted to 115 ° C., and reacted for 1 hour while shaking water through the condenser tube. After completion of the reaction, the flask was removed from the heating bath, and about 5 cc of ion exchange water was added from the top of the condenser tube with a graduated cylinder and shaken. After allowing to cool to room temperature, several drops of phenolphthalein indicator were added, and a 0.5N potassium hydroxide-ethanol solution was titrated. The point where the pale red color lasted for 30 seconds was taken as the end point, and the dripping amount at that time was read. At the same time, a blank test was also performed. The hydroxyl value of the vinyl polymer segment in the composite resin (A-1) was calculated from the following two formulas.

B: Drop amount in blank test (ml)
T: Drop amount in this test (ml)
F: Potency of 0.5N potassium hydroxide-ethanol solution S: Amount of composite resin (A-1) collected (g)
AN: Acid value of composite resin (A-1)

C: Hydroxyl value of composite resin (A-1) N: Solid content ratio (mass%) of composite resin (A-1)
P: Mass ratio (mass%) of the polysiloxane segment (a-1-1) in the solid content of the composite resin (A-1)

From this, the hydroxyl value of the vinyl polymer segment in the composite resin (A-1) was calculated to be 100 mgKOH / g, and the vinyl polymer segment estimated from the HEMA content relative to the total amount of the monomers used was calculated. It was confirmed that the hydroxyl value coincided with the calculated value from the actual measurement value.

(Synthesis Examples 14 to 17: Synthesis of composite resins (A-2) to (A-5))
600 parts of composite resins (A-2) to (A-5) were obtained in the same manner as in Synthesis Example 13 except that the composition was changed to the composition shown in Table 3 below.

Table 3 shows the composition and property values of the composite resins (A-1) to (A-5) obtained above.

(Synthesis Example 18: Synthesis of Composite Resin (R-1))
In the same reaction vessel as in Synthesis Example 1, 512.4 parts of the vinyl polymer (a-2-1) obtained in Synthesis Example 8 and polysiloxane (a-1-6) obtained in Synthesis Example 6 After charging 106.7 parts and stirring for 5 minutes, 16.7 parts of deionized water was added and the mixture was stirred at 80 ° C. for 4 hours. The vinyl polymer (a-2-1) and the polysiloxane (a-1 The hydrolysis condensation reaction of -6) was performed. The obtained reaction product was distilled under reduced pressure of 1 to 30 kPa at 40 to 60 ° C. for 2 hours to remove the produced methanol and water, and then 36.0 parts of PGMAC, n-acetate 140.2 parts of butyl was added to obtain 600 parts of a comparative composite resin (R-1) composed of a polysiloxane segment having a nonvolatile content of 55.0% and a vinyl polymer segment.

(Synthesis Examples 19 to 22: Synthesis of composite resins (R-2) to (R-5))
600 parts of composite resins (R-2) to (R-5) were obtained in the same manner as in Synthesis Example 18 except that the composition was changed to the composition shown in Table 4 below.

(Synthesis Example 23: Synthesis of Composite Resin (R-6))
In a reaction vessel similar to Synthesis Example 1, 502.7 parts of the vinyl polymer (a-2-1) obtained in Synthesis Example 8 and polysiloxane (a-1-5) obtained in Synthesis Example 5 106. 7 parts and “BGE-R” (butyl glycidyl ether manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), which is an epoxy compound having no hydrolyzable silyl group, for comparison with an epoxy group-containing silane compound. Add 9 parts and stir for 5 minutes, then add 36.9 parts of deionized water and stir for 4 hours at 80 ° C. to give vinyl polymer (a-2-1) and polysiloxane (a-1-5) The hydrolysis condensation reaction of was performed. Here, the addition amount of BGE-R is determined by calculation so that the epoxy equivalent of the solid content of the finally obtained composite resin and epoxy compound mixture is 8800 g / eq. At this time, the obtained reaction product was distilled under reduced pressure of 1 to 30 kPa at 40 to 60 ° C. for 2 hours to remove the generated methanol and water, and then 36.0 parts of PGMAC, 143.2 parts of n-butyl acetate was added to obtain 600 parts of a composite resin (R-6) composed of a polysiloxane segment having a nonvolatile content of 55.2% and a vinyl polymer segment.

(Synthesis Example 24: Synthesis of composite resin (R-7))
In the same reaction vessel as in Synthesis Example 1, 497.4 parts of the vinyl polymer (a-2-1) obtained in Synthesis Example 8 and polysiloxane (a-1-5) obtained in Synthesis Example 5 106. 7 parts and “4HBAGE” (4-hydroxybutyl acrylate glycidyl ether manufactured by Nippon Kasei Co., Ltd.), an epoxy compound having no hydrolyzable silyl group, for comparison with an epoxy group-containing silane compound After adding 5 parts and stirring for 5 minutes, 36.9 parts of deionized water was added and stirred at 80 ° C. for 4 hours to give a vinyl polymer (a-2-1) and polysiloxane (a-1-5). ) Hydrolysis condensation reaction. Here, the amount of 4HBAGE added is determined by calculation so that the epoxy equivalent of the finally obtained composite resin (R) and epoxy compound mixture is 8800 g / eq. At this time, the obtained reaction product was distilled under reduced pressure of 1 to 30 kPa at 40 to 60 ° C. for 2 hours to remove the generated methanol and water, and then 36.0 parts of PGMAC, 143.6 parts of n-butyl acetate was added to obtain 600 parts of a composite resin (R-7) composed of a polysiloxane segment having a nonvolatile content of 55.3% and a vinyl polymer segment.

Table 4 shows the composition and property values of the composite resins (R-1) to (R-7) obtained above.

(Evaluation)
The composite resins (A-1) to (A-5) and composite resins (R-1) to (R-7) obtained above were evaluated as follows. That is, the “color tone”, “turbidity” and “storage stability” of the resin were evaluated.

<Color tone>
The color of the obtained Gardner color (value measured by the color test method for chemical products specified in JIS K 0071-2) is visually compared with the standard sample specified in JIS K 0071-2. Determined by. The smaller the Gardner color number, the lighter the coloration, and it was determined that the Gardner color number was 1 or less and the resin was colorless.

<Turbidity>
The turbidity of the obtained resin was determined in accordance with JIS K0101, using a precision photoelectric turbidimeter T-2600S (manufactured by Tokyo Denshoku), integrating sphere scattering photometry (change in forward scattered light due to formation of aggregates). , Measured using an integrating sphere, and measured under optical conditions according to a method for comparing the ratio with transmitted light intensity). The smaller the turbidity, the higher the transparency. The turbidity was determined to be a highly transparent resin having a turbidity of 0.5 or less and no turbidity.

<Storage stability>
The storage stability of the obtained resin was evaluated based on the viscosity ratio with the viscosity (so-called viscosity with time) of what was stored at 40 ° C. for 30 days as the numerator and the initial viscosity as the denominator. The viscosity was measured at 30 ° C. using an E-type viscometer (manufactured by Tokyo Keiki Co., Ltd.). The sample was stored by placing the obtained resin in a glass tube and allowing it to stand at 40 ° C. for 1 month. The closer this viscosity ratio is to 1, the better the storage stability, and the more excellent the storage stability with a viscosity ratio of 0.9 to 1.1. It was judged that there was.

Each evaluation result is shown in Table 3 and Table 4.

As a result, the composite resins (A-1) to (A-5) obtained in Synthesis Examples 13 to 17 and the composite resins (R-1) to (R-2) obtained in Synthesis Examples 18 to 19 were obtained. Were found to have good color tone, turbidity and storage stability.
On the other hand, the composite resins (R-3) to (R-4) obtained in Synthesis Examples 20 to 21 are examples in which the epoxy equivalent of the composite resin is larger than 17000 g / eq, but it was found that the storage stability was inferior. did.
In addition, the composite resins (R-5) to (R-7) obtained in Synthesis Examples 22 to 24 are examples in which polysiloxane does not have an epoxy group, but it has been found that the storage stability is poor.

Example 1
25.0 parts by mass of composite resin (A-1) obtained in Synthesis Example 1, Barnock DN-980 (manufactured by Polyisocyanate DIC Corporation, the diluent solvent is ethyl acetate, and the non-volatile content is 75.3% by mass Further, by mixing 4.5 parts by mass of NCO% of varnish (16.0% by mass) and 18.9 parts by mass of ethyl acetate, a curable resin composition having a nonvolatile content of 55.0% by mass is obtained. The curable resin composition was designated as a clear paint (1).

(Examples 2-5 and Comparative Examples 1-2)
Based on the formulation shown in Table 5 below, clear paints (2) to (5) and comparative clear paints (R1) to (R2) were prepared in the same manner as in Example 1.

(Evaluation)
The clear paints (1) to (5) and the comparative clear paints (R1) to (R2) obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were evaluated as follows. That is, the “color tone” of the clear coating, the cured coating film X or Y for evaluation, the “gel fraction” serving as an index of room temperature curability of the cured coating film, and the “gloss retention ratio” serving as an index of weather resistance. evaluated.

<Color tone>
The obtained clear paint has a Gardner color number (measured by the color test method for chemical products specified in JIS K 0071-2) and is visually color-matched with a standard sample specified in JIS K 0071-2. Was determined. The smaller the Gardner color number, the lighter the coloration, and it was determined that the Gardner color number was 1 or less and the resin was colorless.

(Evaluated cured coating X)
Each of the clear paints obtained in Examples 1 to 5 and Comparative Examples 1 and 2 was applied onto a 150 mm × 70 mm × 2 mm polypropylene (PP) substrate using a number 16 bar coater, and at room temperature. For 1 week to prepare a cured coating film having a dry film thickness of 20 μm.

(Evaluated cured coating Y)
150 mm x 70 mm x 2 mm chrome-treated aluminum steel sheet, white acrylic urethane paint with a pigment weight concentration (PWC) of 60%, using a number 22 bar coater to a dry film thickness of 30-40 micrometers (μm) Each of the clear coatings obtained in Examples 1 to 5 and Comparative Examples 1 and 2 was applied to a base material that had been coated and thermally cured at 80 ° C. for 30 minutes using a number 16 bar coater. It was applied and allowed to stand at room temperature for 1 week to prepare a cured coating film having a dry film thickness of 20 μm.

<Gel fraction>
The cured coating film X for evaluation was peeled off from the PP base material, and the coating film residual amount (mg) after immersion in acetone for 24 hours was divided by the mass (mg) of the cured coating film before immersion in acetone. The value multiplied by 100 was displayed as the gel fraction (%). The closer the gel fraction was to 100%, the better the room temperature curability, and it was determined that the cured coating film had sufficient room temperature curability when the gel fraction was 80% or more.

<Gloss retention>
An accelerated weather resistance test using a sunshine weatherometer (SWOM) was performed on the cured coating film Y for evaluation. The test conditions conform to the paint standard (JIS-D0205) that is assumed for paints for automobiles or automobile parts as standard, the black panel temperature is 63 ± 3 ° C, and the water injection time is the last of 60 minutes of irradiation time. The sample surface irradiance was set to 255 ± 10 W / m ² in the wavelength region of 300 to 700 nm. Gloss retention of the value obtained by dividing the 60-degree specular reflectance (%) of the cured coating after 3000 hours test using SWOM by the 60-degree specular reflectance (%) of the untested cured coating and multiplying by 100 Expressed as a percentage (%). It was determined that the closer the gloss retention rate was to 100%, the better the weather resistance, and the cured coating film having sufficient gloss resistance when the gloss retention rate was 80% or more.

Each evaluation result is shown in Table 5.

As a result, the clear paints (1) to (5) evaluated in Examples 1 to 5 were all colorless, had good gel fraction and gloss retention after curing, and were excellent in room temperature curability and weather resistance. A coating film was obtained.
The clear paint (R1) evaluated in Comparative Example 1 is an example in which the epoxy equivalent of the composite resin is too small, but it has been found that room temperature curability and weather resistance are poor.
The clear paint (R2) evaluated in Comparative Example 2 is an example in which the hydroxyl value of the vinyl polymer segment is too small, but it has been found that the room temperature curability and weather resistance are poor.

(Example 6)
25.0 parts by mass of the composite resin (A-1) obtained in Synthesis Example 1, 4.5 parts by mass of Bernock DN-980, CR-97 (rutile titanium oxide manufactured by Ishihara Sangyo Co., Ltd.), 9.2 parts by mass, Enamel paint (1) was obtained by mixing 28.3 parts by mass of ethyl acetate.

(Example 7 and Comparative Examples 3 to 4)
Based on the formulation shown in Table 6, enamel paint (2) and comparative enamel paints (R1) to (R2) were prepared in the same manner as in Example 6.

(Evaluation)
The enamel paints (1) to (2) and the comparative enamel paints (R1) to (R2) obtained in Examples 6 to 7 and Comparative Examples 3 to 4 were evaluated as follows. That is, the cured coating film X or Y for evaluation was used to evaluate the “gel fraction” that is an index of room temperature curability of the cured coating film and the “gloss retention ratio” that is an index of weather resistance.

(Evaluated cured coating X)
Each enamel paint obtained in Examples 6 to 7 and Comparative Examples 3 to 4 was applied onto a polypropylene (PP) substrate of 150 mm × 70 mm × 2 mm using a number 16 bar coater, and room temperature was applied. A cured coating film having a dry film thickness of 20 μm was prepared by allowing it to stand for 1 week.

(Evaluated cured coating Y)
A 150 mm x 70 mm x 2 mm chromate-treated aluminum steel sheet is coated with white acrylic urethane paint with a pigment weight concentration (PWC) of 60% so that the dry film thickness is 30-40 micrometers (μm) using a number 22 bar coater. Each of the enamel paints obtained in Examples 6 to 7 and Comparative Examples 3 to 4 was applied to a substrate that had been applied and thermally cured at 80 ° C. for 30 minutes using a number 16 bar coater. The cured coating film having a dry film thickness of 20 μm was prepared by allowing it to stand at room temperature for 1 week.

<Gel fraction>
The cured coating film X for evaluation was peeled off from the PP base material, and the coating film residual amount (mg) after immersion in acetone for 24 hours was divided by the mass (mg) of the cured coating film before immersion in acetone. The value multiplied by 100 was displayed as the gel fraction (%). The closer the gel fraction was to 100%, the better the room temperature curability, and it was determined that the cured coating film had sufficient room temperature curability when the gel fraction was 80% or more. However, the pigment solid content is not a curing component and is excluded from the calculation.

<Gloss retention>
An accelerated weather resistance test using a sunshine weatherometer (SWOM) was performed on the cured coating film Y for evaluation. The test conditions conform to the paint standard (JIS-D0205) that is assumed for paints for automobiles or automobile parts as standard, the black panel temperature is 63 ± 3 ° C, and the water injection time is the last of 60 minutes of irradiation time. The sample surface irradiance was set to 255 ± 10 W / m ² in the wavelength region of 300 to 700 nm. Gloss retention of the value obtained by dividing the 60-degree specular reflectance (%) of the cured coating after 3000 hours test using SWOM by the 60-degree specular reflectance (%) of the untested cured coating and multiplying by 100 Expressed as a percentage (%). It was determined that the closer the gloss retention rate was to 100%, the better the weather resistance, and the cured coating film having sufficient gloss resistance when the gloss retention rate was 80% or more.

Each evaluation result is shown in Table 6.

As a result, each of the enamel paints (1) to (2) evaluated in Examples 6 to 7 had a good gel fraction and gloss retention, and a coating film excellent in weather resistance was obtained.
The enamel paint (R1) evaluated in Comparative Example 3 is an example in which the epoxy equivalent of the composite resin (A) is too small, but it has been found that the room temperature curability and weather resistance are poor.
The enamel paint (R2) evaluated in Comparative Example 4 is an example in which the hydroxyl value of the vinyl polymer segment (a-2) is too small, but it has been found that the room temperature curability and weather resistance are poor.

The two-component transparent room-temperature curable resin composition in the present invention has both storage stability in a one-component state and good curability at room temperature, and can provide a cured product having excellent weather resistance. . In addition, the paint containing the curable resin composition can be used for metal substrates, inorganic substrates, plastic substrates, paper, wood-based substrates, etc., exterior building members, automobile exterior members, civil engineering applications, electronic members It can be used in various industrial fields such as leisure goods.

Claims (3)

1. A polysiloxane segment (a1) having a structural unit represented by the general formula (1) and / or the general formula (2), a silanol group and / or a hydrolyzable silyl group, and an epoxy group, and an alcoholic hydroxyl group. The vinyl polymer segment (a2) having a curable resin composition containing a composite resin (A) bonded by a bond represented by the general formula (3) and a polyisocyanate (B), The mass ratio of the polysiloxane segment (a1) in the solid content of the composite resin (A) is 20 to 70% by mass, and the epoxy equivalent of the solid content of the composite resin (A) is 900 to 17000 g / eq, The hydroxyl group value of the vinyl polymer segment (a2) is 55 to 200 mgKOH / g, and the mass ratio of the polyisocyanate (B) is 5 to 50 in the total solid content. Curable resin composition, which is a quantity%.
   

   

   

   (In the general formulas (1) and (2), R ¹ , R ² and R ³ each independently represent —R ⁴ —CH═CH ₂ , —R ⁴ —C (CH ₃ ) ═CH ₂ , — A group having one polymerizable double bond selected from the group consisting of R ⁴ —O—CO—C (CH ₃ ) ═CH ₂ and —R ⁴ —O—CO—CH═CH ₂ (provided that R ⁴ Represents a single bond or an alkylene group having 1 to 6 carbon atoms.), An alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group, or 7 carbon atoms. Represents an aralkyl group of ˜12.)
   

   

   (In the general formula (3), carbon atoms constitute a part of the vinyl polymer segment (a2), and silicon atoms bonded only to oxygen atoms constitute a part of the polysiloxane segment (a1). To do)
2. A paint comprising the curable resin composition according to claim 1.
3. An article having a cured coating film formed using the paint according to claim 2.