JPH11323159A - Curable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in weather resistance and low- temperature curability by incorporating a vinyl (co)polymer having hydrolyzable silyl groups and urethane or urea groups as side chains or terminals with a curing catalyst and a solvent. SOLUTION: This composition comprises a vinyl (co)polymer having hydrolyzable silyl groups and urethane or urea groups as side chains or terminals, a curing catalyst (e.g. dibutyltin dilaurate) and a solvent (e.g. xylene). The vinyl (co)polymer is obtained by copolymerizing a polymerizable monomer having a hydrolyzable silyl group (e.g. γ-methacryloxypropyltrimethoxysilane) with a polymerizable monomer having an isocyanate group (e.g. dimethyl-m- isopropenylbenzyl isocyanate), and other polymerizable monomers (e.g. methyl methacrylate) and reacting the isocyanate group with a compound having an alcoholic or phenolic hydroxyl group or an amine (e.g. dibutylamine) during or after the polymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable resin composition having excellent weather resistance and capable of producing a product useful as a paint, an adhesive or a sealing agent, particularly as a top coat.

[0002]

2. Description of the Related Art Conventionally, a curable resin having a hydrolyzable silyl group (for example, an acrylic silicone resin) has been used as a resin for paints, especially at room temperature curable overcoats, because of its good weather resistance due to its molecular structure. Widely used as a coating resin. In the case of such a room-temperature-curable acrylic silicone paint, it is hydrolyzed by moisture in the air or moisture generated by the reaction, and further condensation-crosslinks,
Generates siloxane bonds. Recently, for the purpose of improving solvent resistance and the like, a polyisocyanate and a catalyst have been added to a resin having a hydrolyzable silyl group and a hydroxyl group,
A method using both siloxane crosslinking and urethane crosslinking has also been proposed.

[0003]

However, a coating film using a siloxane bond cannot be said to have good adhesiveness, probably due to the shrinkage of the cured product due to the condensation reaction. Particularly, in recent years, the required performance has been strict with technological progress, and water resistance at low temperatures is insufficient. Further, the method using both siloxane crosslinking and urethane crosslinking has a fundamental problem that the stability between the polyisocyanate and the catalyst (such as alkyltin) is poor. In addition, in terms of performance, simply adding urethane cross-linking results in too high a cross-linking density, which has an adverse effect on coating performance such as a decrease in adhesiveness. I will.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, by introducing a specific polar group into a resin having a hydrolyzable silyl group, I found that the problem could be solved. That is,
The present invention relates to a curable resin comprising (A) a vinyl (co) polymer having a hydrolyzable silyl group and a urethane group or a urea group in a side chain or a terminal, (B) a curing catalyst, and (C) a solvent. A composition.

[0005]

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

[0006]

Embedded image

(R ₃ 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. ).

There are several methods for synthesizing a vinyl (co) polymer having a hydrolyzable silyl group and a urethane or urea group at the side chain or terminal, which is the component (A) of the present invention. It is possible. For example, a polymerizable monomer (a) having a hydrolyzable silyl group, a polymerizable monomer (b) having an isocyanate group, and another polymerizable monomer (c) are copolymerized. Or after polymerization, a method of reacting an isocyanate group with a compound having an alcoholic or phenolic hydroxyl group, or an amine,
A method of copolymerizing a polymerizable monomer (a) having a hydrolyzable silyl group, a polymerizable monomer (d) having a urethane group or a urea group, and another polymerizable monomer (c),
A method of graft-polymerizing a polymerizable monomer having a hydrolyzable silyl group to an acrylic polymer having a urethane group or a urea group, having an urethane group or a urea group and having an acrylic polymer having a functional group, A method of reacting a compound containing a group capable of reacting with a functional group and having a hydrolyzable silyl group (for example, reacting a polymer having a carbon-carbon double bond with a silicon hydride compound under a platinum-based catalyst) Or a method of reacting glycidoxypropyltrimethoxysilane with a polymer having an amino group). Among these, from the viewpoint of ease of reaction and cost,
Or method is most preferred.

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 Diethoxysilane, γ-acryloxypropyltrimethoxylane, γ-acryloxypropyltrimethoxylane, γ-acryloxypropylmethyldimethoxylane, γ-acryloxypropyltriethoxylane, γ-
Acryloxypropylmethyldiethoxysilane, γ-methacryloxyethoxypropyltrimethoxylan and the like can be mentioned.

[0010] The monomer (a) is a major factor in determining the durability of the curable resin of the present invention, and is desirably as large as economically permits. However, in applications such as paints, the excessively crosslinked structure has a practical upper limit due to the need to maintain the flexibility of the coating film. From such a 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 copolymerization amount is too large, the crosslink density of the curable resin is too high, and the resin does not become a general-purpose curable resin.

As the polymerizable monomer (b) having an isocyanate group, methacryloyloxyisocyanate,
Methacryloyloxyethyl isocyanate, dimethyl meta-isopropenylbenzyl isocyanate, and the like. The copolymerization amount of the monomer (b) is 1 to 40 mol%
Is preferred. More preferably, it is 1 to 20 mol%. If the copolymerization amount is too small, a sufficient effect cannot be obtained,
Further, even if the copolymerization amount is further increased, there is no effect and the cost is disadvantageous.

Regarding the other polymerizable monomer (c),
There is no particular limitation, and generally methacrylates, acrylates, vinyl esters, various vinyl compounds, and the like can be used. For example, acrylic acid such as methyl acrylate, methyl methacrylate, butyl acrylate, and butyl methacrylate can be used. , Methacrylic acid esters; monomers containing an amide group such as acrylamide, methacrylamide, dimethylaminopropyl acrylamide, N-methylol acrylamide, monomers containing an amino group such as diethylaminoethyl acrylate, aminoethyl vinyl ether,
Examples thereof include acrylic acids such as acrylic acid and methacrylic acid, acrylonitrile, styrene, α-methylstyrene, vinyl acetate, and vinyl propionate. The copolymerization amount of such a monomer (c) is preferably from 20 to 98 mol%. If the copolymerization amount is too small, the crosslinked structure of the curable resin becomes too dense, and it is not preferable because it does not become a general-purpose curable resin. If it is too large, sufficient durability and weather resistance cannot be obtained, which is not preferable.

Examples of the compounds having an alcoholic or phenolic hydroxyl group or amines used in the method of the present invention include alkyl alcohols such as methanol, ethanol, propanol and butanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve and propylene. Alcohol ethers such as glycol monomethyl ether; phenols such as phenol and cresol; and amines such as butylamine, diethylamine and dibutylamine. These may be added during polymerization and reacted simultaneously, or may be reacted after polymerization. However, since a hydrolyzable silyl group coexists, mild conditions must be selected when using phenols and amines.

As the polymerizable monomer (d) having a urethane group or a urea group used in the method of the present invention, various monomers having a urethane group or a urea group can be used. For example, it can also be synthesized by previously reacting the polymerizable monomer (b) having an isocyanate group and the compound or amine having an alcoholic or phenolic hydroxyl group also exemplified above. .

The (A) vinyl (co) polymer of the present invention comprises:
For example, it can be performed by a usual solution polymerization method. That is, a monomer (a), a monomer (b), a monomer (c), a polymerization initiator, and a solvent are added and reacted at about 50 to 160 ° C. For the purpose of adjusting the molecular weight, a chain transfer agent such as dodecyl mercaptan may be added. Although it does not specifically limit as a solvent, aliphatic or aromatic hydrocarbons, alcohols, ethers, esters, alcohol ethers, etc. are used.

The curing catalyst of the component (B) of the present invention includes
Metal fatty acid salts, metal alcoholates, amine compounds and the like can be used. Specifically, dibutyltin diacetate,
Examples include dibutyltin dioctate, dibutyltin dilaurate, butyltin trioctate, tetrapropoxytitanium, tetrabutoxytitanium, and various amine compounds.

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

In addition, the curable composition of the present invention can be cured not only by absorbing moisture in the air but also by moisture generated by the reaction. By using this curing method, a composition which is less affected by the external environment and has excellent low-temperature curability can be obtained. Specifically, as the component (A), a hydrolyzable silyl group, a urethane group or a urea group and a compound represented by the general formula (I)

[0019]

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(R _{1 to} R ₂ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.) A vinyl (co) polymer having a group represented by the formula (B): Can be achieved by using a compound having at least one primary amino group.

The vinyl (co) polymer having a hydrolyzable silyl group, urethane group or urea group and a group represented by the general formula (I) on the side chain or terminal of the component (A) is as follows: As described above, the polymerizable monomers (a), (b) and (c) are copolymerized with the polymerizable monomer (e) having a group represented by the general formula (1), and the isocyanate is obtained. The group is a urethane group or a urea group, or a polymerizable monomer (a),
It is obtained by copolymerizing (d) and (c) with a polymerizable monomer (e) having a group represented by the general formula (1). Examples of the polymerizable monomer (e) having a group represented by the general formula (1) include diacetone acrylamide,
Examples include acetoacetoxyethyl methacrylate.

Examples of compounds having at least one primary amino group include, for example, methylamine, ethylamine, propylamine, butylamine, hexylamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, N-
(2-aminoethyl) piperazine, aminopropyltriethoxysilane, aminopropyltrimethoxysilane,
Monoamines such as aminoethylaminopropyltriethoxysilane and aminoethylaminopropyltrimethoxysilane; ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, xylylenediamine, bis (aminocyclohexyl) methane, 2,2-bis (amino) Cyclohexyl) propane,
Metaphenylenediamine, diaminodiphenylmethane,
Diamines such as diaminodiphenylsulfone; hydrazides such as hydrazine, acetohydrazide, benzoic hydrazide, salicylic acid hydrazide, carbodihydrazide, adipic dihydrazide; and polymers containing primary amino groups. Examples of the polymer containing a primary amino group include a polyamide resin obtained from a divalent fatty acid and a divalent amine, and a resin obtained by adding a polyvalent amine to various epoxy resins. In addition, a primary amino group can be introduced into a side chain of an acrylic resin, a polyester resin, a polyurethane resin, or a vinyl resin to be used. 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 general formula (I).

In using the curable resin composition of the present invention, various known additives such as a dehydrating agent, an antioxidant,
An ultraviolet absorber, a fluidity regulator, a pigment, a dispersant, a surfactant, a catalyst, and the like can be added.

[0024]

EXAMPLES <Synthesis Example 1—Synthesis of Urethane Group-Containing Polymerizable Monomer> A reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube was charged with propylene glycol monomethyl ether (PGM, primary grade). Alcohol 99% or more) 3
3.3 parts were charged and refluxed under a nitrogen atmosphere. further,
9.0 parts of dimethyl meta-isopropenyl benzyl isocyanate (TMI, manufactured by Mitsui Cytec Co., Ltd.) was added dropwise over 30 minutes under total reflux. Then, while maintaining the total reflux,
Sampling was carried out every hour, and the absorption of isocyanate groups was monitored by an infrared spectrophotometer. After 9 hours, it was confirmed that 95% or more of the reaction had occurred, and the reaction was terminated. As a result of titration of the isocyanate group of the obtained monomer solution (dibutylamine method), the conversion was 99.8%. As a result of analysis by GPC, no polymer was detected.

<Synthesis Example 2—Polymerization of Vinyl Copolymer> A solvent (kind and amount shown in Table 1) was charged into the same reactor as in Synthesis Example 1, and the temperature was increased to 132 ° C. in a nitrogen atmosphere. After the temperature was raised, the mixture shown in Table 1 was added dropwise over 3 hours under total reflux. During this time, the temperature rose to 137 ° C. After completion of the dropwise addition, the mixture was kept at the same temperature for 1 hour, and tert-butyl par 2-
1.0 part of ethyl hexanoate was added and the mixture was kept for another 2 hours. Thereafter, while maintaining the total reflux, sampling was performed every hour, the absorption of isocyanate groups was monitored by an infrared spectrophotometer, and it was confirmed that 95% or more had reacted, and the reaction was terminated. Table 1 shows the resin properties of the obtained resin.

[0026]

[Table 1]

<Synthesis Examples 6 and 7 and Comparative Synthesis Examples 1 and 2> Solvents (kinds and amounts shown in Table 2) were placed in the same reactor as in Synthesis Example 1.
Was heated to 139 ° C. under a nitrogen atmosphere, and the mixture shown in Table 2 was added dropwise over 3 hours under total reflux. After completion of the dropwise addition, the mixture was kept at the same temperature for 1 hour, and tert-butyl par 2-
1.0 part of ethyl hexanoate was added and the mixture was kept for another 2 hours. Table 2 shows the resin properties of the obtained resin.

[0028]

[Table 2]

<Synthesis Example 8> In the same reactor as in Synthesis Example 1,
168.6 parts of the resin of Synthesis Example 7 were charged and placed under a nitrogen atmosphere.
At room temperature, 5.7 parts of dibutylamine was added dropwise over 10 minutes.
Hold for hours. The nonvolatile content of the obtained resin is 62.1%,
B-type viscosity 11.7 Poise, weight average molecular weight 21,8
00, the conversion of isocyanate was 99.9%.

<Example of paint preparation> 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 resin of the type and amount (parts by weight) shown in Table 3.
And 6.1 parts of xylene. More beads 4
7.4 parts were added, and the mixture was dispersed using a quick mill until the degree of dispersion was reduced to 10 μm or less using a grain gauge to prepare a mill base. Further, 7.4 parts of xylene and 0.1 part of Disparon OX-77 (manufactured by Kusumoto Kasei Co., Ltd.) of the kind and amount (parts by weight) shown in Table 3 were added and mixed, and the paint was prepared. Created. Table 3 shows the viscosity and specific gravity at this time.

[0031]

[Table 3]

<Evaluation of coating film performance 1> A test plate spray-coated with NY Porin K middle coat (manufactured by Shinto Paint Co., Ltd.) with an average film thickness of 25 μm was dried at room temperature for 4 days. Table 4
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 performed in S-WOM for 5000 hours, and the gloss retention was measured. -Acid resistance and alkali resistance: The sample plate was immersed in 10% H2SO4 or 10% NaOH for 24 hours, and the surface was observed. -Boiling water resistance: The test plate was dried for one day, immersed in boiling water for 24 hours, and evaluated. ○: No abnormality

[0033]

[Table 4]

<Evaluation of coating film performance 2> In order to examine the coating film performance at a low temperature, a NY Porin K intermediate coat was similarly applied and dried at 5 ° C for 4 days. Furthermore, the same top coat was dried at 5 ° C. after application. Its low temperature water resistance,
Table 5 shows the results of evaluating the low-temperature recoating property and the gel fraction. -Low-temperature water resistance: After top coating, dried for one 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 a cellophane tape. ：: no peeling ：: partial peeling ×: full peeling ・ Low temperature recoating property: After the number of days shown in Table 5, the same top coat was applied by brush and the surface was observed. ：: No abnormalities ×: Occurrence of blemising Dissolution: Dissolution of coating film ・ Gel fraction: At the time of top coating, together with each test piece,
A polyethylene test plate was also sprayed, the coating film was peeled off, dissolved in acetone, and a gel fraction was determined from the soluble matter.

[0035]

[Table 5]

[0036]

According to the present invention, by introducing a specific polar group into a side chain or a terminal of a curable resin having a hydrolyzable silyl group, coating film performance, particularly low-temperature water resistance, can be greatly improved. . Further, by incorporating a mechanism of curing by moisture generated by the reaction, low-temperature curability was able to be improved.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09D 133/14 C09D 133/14 133/24 133/24 143/04 143/04 201/10 201/10 C09J 133/14 C09J 133 / 14 143/04 143/04

Claims (2)

[Claims] 1. A curable composition comprising (A) a vinyl (co) polymer having a hydrolyzable silyl group and a urethane group or a urea group in a side chain or a terminal, (B) a curing catalyst, and (C) a solvent. Resin composition. 2. A component (A) having a hydrolyzable silyl group, a urethane group or a urea group at a side chain or at a terminal, and a compound represented by the formula (I) (R _{1 and} R ₂ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.) A vinyl (co) polymer having a group represented by the following formula (B): The curable resin composition according to claim 1, which is a compound having at least one group.