JP3466917B2 - Curable resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a curable resin composition having excellent weather resistance and capable of producing a useful product as a paint / adhesive / sealing agent, particularly for a topcoat paint.

[0002]

2. Description of the Related Art Conventionally, a curable resin having a hydrolyzable silyl group (for example, an acrylic silicone resin) has a good weather resistance derived from its molecular structure, and therefore, as a resin for paints, particularly a room temperature curable topcoat. Widely used as paint resin. In the case of such room-temperature-curable acrylic silicone paint, first, the hydrolyzable silyl group is hydrolyzed by the water in the air, and subsequently, it is cured by a reaction of forming a siloxane bond. On the other hand, the present inventors have previously proposed a curing mechanism in which a siloxane bond is formed by water produced by introducing an acetoacetyl group into a resin having a hydrolyzable silyl group and reacting it with an amine. did. (Japanese Patent Application Laid-Open No. 9-118831) By introducing such a curing mechanism, stable curing can be achieved without being affected by the external environment such as humidity and temperature.

[0003]

However, when a curable resin having a hydrolyzable silyl group and an acetoacetyl group is made into a paint, it may cause thickening or gelation depending on the type of pigment, resulting in storage stability. Turned out to be a problem. It is considered that this is because the acetoacetyl group is an acidic substance and that the surface treatment agent is partly released during the dispersion of the pigment to act as a catalyst and the silyl group is polymerized during storage. In addition, a coating material using a curable resin having a hydrolyzable silyl group and an acetoacetyl group has a characteristic of being excellent in low-temperature curability, but the adhesiveness is insufficient because the curing is too fast and shrinkage occurs. The problem arises.

[0004]

The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, in order to generate water for curing the hydrolyzable silyl group, It was found that the problem can be solved by using an imine reaction using a functional group. That is, the present invention provides (A) a hydrolyzable silyl group and general formula (I)

[0005]

[Chemical 1]

(R _{1 to} R ₄ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), a curable resin having a group, and (B) at least one primary amino group. A curable resin composition comprising a compound and a solvent (C).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The hydrolyzable silyl group of the present invention has the general formula (II)

[0008]

[Chemical 2]

(R ₅ is a hydrocarbon group having 1 to 20 carbon atoms, X
Represents a halogen, an alkoxy group having 1 to 20 carbon atoms, an acyloxy group, a phenoxy group, a thioalkoxy group, or a thiophenoxy group, and n represents an integer of 0 to 2. ). Examples of the curable resin having a hydrolyzable silyl group and a group represented by the general formula (I) include vinyl-based (co) polymers such as acrylic resins, polyester resins,
A diallyl phthalate resin or the like can be used. To synthesize a curable resin having such a hydrolyzable silyl group,
Several methods are possible. For example, vinyl (co)
In the case of a polymer, a polymerizable monomer (a) having a hydrolyzable silyl group, a polymerizable monomer (b) having a group represented by the general formula (I) and other polymerizable monomers Copolymer (C), a method of graft-polymerizing a polymerizable monomer having a hydrolyzable silyl group onto an acrylic polymer having a group represented by the general formula (I), a general formula (I ), A method of reacting an acrylic polymer having a functional group with a compound containing a group capable of reacting with the functional group and having a hydrolyzable silyl group (for example, carbon-
There is a method of reacting a polymer having a carbon double bond with a silicon hydride compound under a platinum catalyst, or a polymer having an amino group is reacted with glycidoxypropyltrimethoxysilane). Of these, the method (1) is most preferable in terms of easiness of reaction and cost.

Specific examples of the polymerizable monomer (a) having a hydrolyzable silyl group of the present invention include vinyltrimethoxysilane, vinylbutyltrimethoxysilane, vinyloctyltrimethoxysilane and γ-vinyloxy. Propyltrimethoxysilane, vinyl trimethoxysilylundecanoate, styryltrimethoxysilane, γ-methacryloxypropyltrimethoxylane, γ-methacryloxypropylmethyldimethoxylane, γ-methacryloxypropyltriethoxylane, γ-methacryloxypropylmethyl Diethoxylane, γ-acryloxypropyltrimethoxylane, γ-acryloxypropyltrimethoxylane, γ-acryloxypropylmethyldimethoxylane, γ-acryloxypropyltriethoxylane, γ-
Examples thereof include acryloxypropylmethyldiethoxylane and γ-methacryloxyethoxypropyltrimethoxylane. The monomer (a) is a major factor that determines the durability of the curable resin of the present invention, and it is desirable to increase the amount as much as economically possible. However, in applications such as paints, an excessively crosslinked structure has a practical upper limit because it is necessary to maintain the flexibility of the coating film. From this viewpoint, the copolymerization amount of the monomer (a) is preferably 1 to 40 mol%. More preferably, it is 1 to 20 mol%. If the copolymerization amount is too small, sufficient durability and weather resistance cannot be obtained. On the other hand, if the amount of copolymerization is too large, the crosslink density of the curable resin is too high, and the curable resin cannot be a general-purpose curable resin.

Examples of the polymerizable monomer (b) having a group represented by the general formula (I) include diacetone acrylamide, which is used in an amount of 0 mol based on 1 mol of the hydrolyzable silyl group. It is preferably about 1 to 1.0 mol.

Regarding the other polymerizable monomer (c),
There is no particular limitation, and generally, methacrylic acid esters, acrylic acid esters, vinyl esters, various vinyl compounds and the like can be used. For example, acrylic acid such as methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, etc. Methacrylic acid ester; amide group-containing monomer such as acrylamide, methacrylamide, dimethylaminopropylacrylamide, N-methylolacrylamide, amino group-containing monomer such as diethylaminoethyl acrylate, aminoethyl vinyl ether,
Examples thereof include acrylic acids such as acrylic acid and methacrylic acid, as well as acrylonitrile, styrene, α-methylstyrene, vinyl acetate and vinyl propionate. The copolymerization amount of such a monomer (c) is preferably 60 to 99 mol%. If the amount of copolymerization is small, the crosslink structure of the curable resin becomes too dense and a general-purpose curable resin is not obtained, and if it is too large, sufficient durability and weather resistance cannot be obtained, which is not preferable.

The curable resin of the present invention can be synthesized by, for example, a usual solution polymerization method. That is, the monomer (a), the monomer (b), the monomer (c), the polymerization initiator and the solvent are added and the reaction is carried out at about 50 to 160 ° C. A chain transfer agent such as dodecyl mercaptan may be added for the purpose of adjusting the molecular weight. The solvent is not particularly limited, but aliphatic or aromatic hydrocarbons, alcohols, ethers, esters, alcohol ethers and the like are used.

Examples of the compound having at least one primary amino group of the component (B) of the present invention include, for example, methylamine, ethylamine, propylamine, butylamine, hexylamine, dimethylaminopropylamine,
Monoamines such as diethylaminopropylamine, dibutylaminopropylamine, N- (2-aminoethyl) piperazine, aminopropyltriethoxysilane, aminopropyltrimethoxysilane, aminoethylaminopropyltriethoxysilane and aminoethylaminopropyltrimethoxysilane. Diamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, xylylenediamine, bis (aminocyclohexyl) methane, 2,2-bis (aminocyclohexyl) propane, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone; Hydrazine, acetohydrazide, benzoic acid hydrazide, salicylic acid hydrazide, carbodihydrazide, adipic acid dihydrazide Polymer or the like can be used include primary amino group; hydrazides and the like. Examples of the polymer containing a primary amino group include a polyamide resin obtained from a divalent fatty acid and a divalent amine, a resin obtained by adding a polyvalent amine to various epoxy resins, and the like. Further, a primary amino group can be introduced into the side chain of an acrylic resin, a polyester resin, a polyurethane resin, or a vinyl resin for use. The compound containing at least one primary amino group is preferably used in an amount of about 0.5 to 5 mol of the amino group based on the group represented by the formula (I).

As the solvent of the component (C) of the present invention, only the solvent used in the synthesis of the curable resin may be used, or a known solvent may be used if necessary. Specifically, aliphatic or aromatic hydrocarbons, alcohols, ethers, esters, alcohol ethers and the like are used.

In using the curable resin composition of the present invention, various known additives such as dehydrating agents, antioxidants,
An ultraviolet absorber, a fluidity modifier, a pigment, a dispersant, a surfactant and a catalyst can be added.

[0017]

EXAMPLES <Synthesis Examples 1 to 3 and Comparative Synthesis Example 1> A reactor equipped with a stirrer, a thermometer, a reflux cooling pipe and a nitrogen introducing pipe was charged with the solvent shown in Table 1 and was put under a nitrogen atmosphere at 117.
The temperature was raised to 0 ° C., and the mixture shown in Table 1 was added dropwise over 3 hours under total reflux. During this time, the temperature rose to 124 ° C. After the completion of the dropping, the temperature was maintained for 1 hour, 0.6 part of tert-butylper-2-ethylhexanoate was added, and the temperature was further maintained for 2 hours. The resin characteristics of the obtained resin are shown in Table 1.

[0018]

[Table 1]

<Preparation Example of Paint> 27.0 parts of titanium oxide CR-97 (manufactured by Ishihara Sangyo Co., Ltd.) and 1.8 parts of trimethyl orthoacetate were added to the resins of the types and amounts (parts by weight) shown in Table 2.
And 6.3 parts of xylene were added and mixed. More beads 4
7.4 parts were added, and the mixture was dispersed with a quick mill until the degree of dispersion became 10 μm or less with a grain gauge to prepare a mill base. Further, the types and amounts (parts by weight) shown in Table 2 for reddown resin, 7.7 parts of xylene, and 0.1 parts of Disparlon OX-77 (manufactured by Kusumoto Kasei Co., Ltd.) were added and mixed to form a paint. Created. The viscosity and specific gravity at this time are shown in Table 2.

[0020]

[Table 2]

<Paint storage stability> The paint was stored at 50 ° C and the stability was checked. The results are shown in Table 3.

[0022]

[Table 3]

<Evaluation of coating film performance 1> A test plate coated with NY Porin K intermediate coating (manufactured by Shinto Paint Co., Ltd.) with an average film thickness of 25 μm was dried at room temperature for 4 days. Furthermore, Table 4
The top-coat paint (main agent + curing agent + thinner) shown in 1 above was spray-coated with an average film thickness of 20 μm and dried at room temperature. Table 4 shows the results of evaluation of the initial gloss value, weather resistance, acid / alkali resistance, and boiling water resistance. Weather resistance: Accelerated weather resistance was measured by S-WOM for 5000 hours, and gloss retention was measured. Acid / Alkali resistance: The sample plate was immersed in 10% H ₂ SO ₄ or 10% NaOH for 24 hours, and the surface was observed. Resistance to boiling water: The test plate was dried for 1 day and then immersed in boiling water for 24 hours for evaluation. ◯: No abnormality.

[0024]

[Table 4]

<Coating film performance evaluation 2> In order to examine the coating film performance at low temperature, similarly, NY Porin K intermediate coating was applied and then dried at 5 ° C. for 4 days. Further, a similar top coating composition was applied and dried at 5 ° C. Its low temperature water resistance,
Table 5 shows the results of evaluation of low temperature recoatability and gel fraction. -Low temperature water resistance: After top coating, it was dried for 1 day and immersed in water. After the elapsed time shown in Table 5, a cross-cut was made with a cutter, and a peeling test was performed with cellophane tape. ◯: No peeling Δ: Partial peeling ×: Whole surface peeling / low temperature recoatability After the lapse of days shown in Table 5, the same topcoat paint was applied with a brush and the surface was observed. ◯: No abnormality X: Twist generation Dissolution: Coating film dissolution / Gel fraction: At the time of top coating, with each test piece,
A polyethylene test plate was also sprayed, the coating film was peeled off, the film was dissolved in acetone, and the gel fraction was prepared from the soluble component.

[0026]

[Table 5]

[0027]

INDUSTRIAL APPLICABILITY When a combination of an acetoacetyl group and an amine is used in a curable resin composition that internally generates water and cures a hydrolyzable silyl group, the storage stability of the paint, the water-resistant adhesion, etc. are improved. There were problems, but by utilizing the imine reaction using a specific functional group, a problem-free composition was obtained.

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Claims (3)

(57) [Claims] 1. A hydrolyzable silyl group (A) and a compound of general formula (I) (R _{1 to} R ₄ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), a curable resin having a group, (B) a compound having at least one primary amino group, C) A curable resin composition comprising a solvent. 2. The curable resin composition according to claim 1, wherein the curable resin as the component (A) is a vinyl (co) polymer. 3. The component (A) is represented by the general formula (II) (R_FiveIs a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen,
C1-C20 alkoxy group, acyloxy group, pheno
An oxy group, a thioalkoxy group, or a thiophenoxy group,
n shows the integer of 0-2. ) Hydrolyzable
Polymerizable Monomer Having Silyl Group and Diacetone Acrylic
Copolymer of amide and, if necessary, other polymerizable monomer
The curable resin composition according to claim 1, which is