JP2937063B2 - Curable coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a one-part liquid
The present invention relates to a curable coating composition which is rapidly cured by heating and exhibits excellent coating film properties and weather resistance.

[0002]

2. Description of the Related Art In recent years, damage to baking paints using a melamine resin as a cross-linking agent due to air pollution, acid rain, and the like has been reported, and countermeasures have been actively promoted in various fields concerned. Many of these measures use a type having either an epoxy group or a carboxyl group (including an acid anhydride group) as a polymer or a crosslinking agent. However, these types of baking paints have not only sufficient water resistance because an ester bond is formed at the time of reaction between an epoxy group and a carboxyl group, and a secondary hydroxyl group is generated by ring opening of the epoxy group. I couldn't say. That is,
Many of the excellent physical properties of epoxy resins are owed to the bisphenol structure and more than compensate for the effects of the generated hydroxyl groups, but when weather resistance is required, it is mainly a cyclic aliphatic epoxy resin, Satisfactory results are not always obtained.

[0003]

SUMMARY OF THE INVENTION The present invention is mainly a baking paint which is stable as a one-part solution, cures quickly at a baking temperature of 100 to 160 ° C. of a metal paint, and has excellent coating properties and weather resistance. The present invention relates to a curable coating composition exhibiting properties.

[0004]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies and as a result, added an unsaturated compound having a (meth) acryloyl group to a polymer having a specific acetoacetyl group. The inventors have found that a composition using an organic compound of cobalt in combination as a curing catalyst can achieve the above object, and have completed the present invention.

Namely, the present invention is (1) obtained by polymerizing or copolymerizing a monomer having an unsaturated group and acetoacetyl group in a molecule, the average number having two or more acetoacetyl groups in the molecule Polymers having a molecular weight of 1,000 to 100,000 , (2) an unsaturated compound having two or more (meth) acryloyl groups in one molecule, and (3) an organic compound of cobalt as (1) and ( 2) 100 parts by weight in total
Curable coating composition characterized in that the composition contains 0.005 to 5 parts by weight of the coating composition.

In the present invention, a polymer having two or more acetoacetyl groups in one molecule of the component (1) is obtained by copolymerizing acetoacetylalkyl (meth) acrylate with a monomer copolymerizable therewith. It is intended to provide the above-mentioned curable coating composition which is a polymer.

Further, according to the present invention, a polymer having two or more acetoacetyl groups in one molecule of the component (1) is obtained by copolymerizing acetoacetylethyl (meth) acrylate and a monomer copolymerizable therewith. It is intended to provide the above curable coating composition which is a polymer.

Further, the present invention relates to an epoxy resin wherein the unsaturated compound as the component (2) is trishydroxyethyl isocyanurate tri (meth) acrylate or (bromine-containing) epoxy resin having at least two epoxy groups in one molecule. Meta)
The present invention provides the curable coating composition, which is a (bromine-containing) vinyl ester resin obtained by reacting acrylic acid.

The present invention also provides the above curable coating composition, wherein the organic compound of cobalt (3) is an organic salt of cobalt or acetylacetonate of cobalt.

Further, the present invention relates to a polymer having two or more acetoacetyl groups in one molecule of the component (1) and an unsaturated compound of the component (2) wherein the proportion of the acetoacetyl group in the polymer of the component (1) is one. It is intended to provide the curable coating composition having two or less (meth) acryloyl groups of the unsaturated compound as the component (2) per unit .

[0011]

It is well known that an acetoacetyl group and a (meth) acryloyl group undergo the following Michael addition reaction in the presence of a strong alkali catalyst such as sodium methylate.

[0013]

Embedded image

Although it is possible to obtain a cured resin by utilizing this reaction with a polymer, the remaining of an alkali compound as a catalyst significantly impairs various physical properties, so that its practical use is greatly hindered.

The inventors of the present invention have studied a catalyst which has a function of accelerating the Michael addition reaction and does not impair the physical properties of the cured resin in place of the alkali catalyst. Was found. When an organic compound of cobalt is used when a cured resin is obtained by the Michael addition reaction, in addition to a rapid curing promoting action, unlike an alkali catalyst, the organic compound of cobalt is water-insoluble and non-corrosive, A practical cured resin can be obtained without impairing electrical properties and water resistance.

The polymer used as the component (1) in the present invention is obtained by polymerizing or copolymerizing a monomer having an unsaturated group and an acetoacetyl group in one molecule, and having two acetoacetyl groups in one molecule. Number average molecular weight 1,
It is a polymer of 000 or more, and can be synthesized by the following method. (A) polymerization of a monomer having an unsaturated group and an acetoacetyl group in one molecule, or (b) formation of a monomer having an unsaturated group and an acetoacetyl group in a molecule and a monomer copolymerizable therewith. It can be synthesized by copolymerization.

Examples of the monomers having an unsaturated group and an acetoacetyl group in one molecule used in the above methods (a) and (b) include, for example, acetoacetylalkyl (meth) acrylate and acetylacetonate of allyl alcohol. Is raised. Acetoacetylalkyl (meth)
As the alkyl of the acrylate, ethyl and propyl are preferable, and specific examples include acetoacetylethyl acrylate, acetoacetylethyl methacrylate, acetoacetylpropyl acrylate, and acetoacetylpropyl methacrylate.

In addition, 1 used in the method (b)
Examples of monomers copolymerizable with a monomer having an unsaturated group and an acetoacetyl group in the molecule include styrene, vinyl toluene, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, T-butyl methacrylate, cyclohexyl methacrylate, ethyl acrylate,
(Meth) acrylic esters such as butyl acrylate and 2-ethylhexyl acrylate; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; acrylonitrile; methacrylonitrile; .

The proportion of the monomer having an unsaturated group and an acetoacetyl group in one molecule and the proportion of the monomer copolymerizable with the monomer are not specified, but preferably the proportion of the copolymerizable monomer is 70 mol%. It is desirable that:

In the above methods (a) and (b),
The method (b) is preferable because a polymer having two or more acetoacetyl groups in one molecule can be stably synthesized. Further, among the above-mentioned polymers, a monomer having an unsaturated group and an acetoacetyl group in one molecule and a monomer copolymerizable with the monomer are copolymerized to form an acetoacetyl group in one molecule.
A copolymer having more than one copolymer is very suitable for the present invention.

In the methods (a) and (b), polymerization or copolymerization is carried out by any of the usual methods. However, the solution polymerization method is convenient since the next step can be directly carried out after completion of the polymerization.

The number average molecular weight of the polymer of the component (1) used in the present invention is 1,000 or more, preferably 3,000 to 100,000, more preferably 50,000.
00 to 50,000.

In the present invention, an unsaturated polymer having two or more (meth) acryloyl groups in one molecule of the component (2) is used by mixing with a polymer having two or more acetoacetyl groups in one molecule of the component (1). The compound is used as a crosslinking agent and may be a monomer or an oligomer. Among these unsaturated compounds, monomers include, for example, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, hexanediol di (meth) acrylate, Methylol propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth)
Acrylate, diacrylate of neopentyl glycol diester of hydroxypivalic acid, 2- (2-hydroxy-1,1'-dimethyl-ethyl) -5-hydroxydimethyl-5-ethyl-1,3-dioxoic acid diacrylate, triacrylate Cyclodecane dimethylol diacrylate,
Trishydroxyethyl isocyanurate tri (meta)
Acrylate, bisphenol A to ethylene oxide adduct di (meth) acrylate, bisphenol A to propylene oxide adduct di (meth) acrylate, novolak to ethylene oxide adduct polyacrylate and the like can be mentioned.

Among the unsaturated compounds of the component (2), oligomers include, for example, (i) an epoxy resin having at least two epoxy groups in one molecule or a bromine-containing epoxy resin and a (meth) acrylic resin. A so-called (bromine-containing) vinyl ester resin (epoxy-acrylate) obtained by reacting an acid, (ii) a polyvalent isocyanate compound having at least two isocyanate groups in one molecule; To an unsaturated urethane to (meth) acrylate obtained by reacting an unsaturated alcohol having a (meth) acryloyl group and a hydroxyl group, (iii) (meth) acrylic acid, polybasic acid (or an acid anhydride thereof) And polyesters to acrylates obtained by esterifying polyhydric alcohols with an acid catalyst. Among these unsaturated compounds having two or more (meth) acryloyl groups in one molecule, unsaturated compounds having two or more acryloyl groups in one molecule are preferably used.

The ratio of the polymer having two or more acetoacetyl groups in one molecule of the component (1) to the unsaturated compound of the component (2) depends on the molecular weights of the components (1) and (2), Although it depends on the content, etc. , generally, the component (1)
(2) component for one acetoacetyl group of the polymer
It is desirable that the proportion of the (meth) acryloyl group in the unsaturated compound be 2 or less , preferably 1. When the number of (meth) acryloyl groups of the component (2) is more than 2 with respect to one acetoacetyl group of the component (1), there is a possibility that radical polymerization is possible, but otherwise the physical properties may be impaired. There are many.

A necessary condition of the present invention is to use an organic compound of cobalt as a curing catalyst in a combined system of the polymer (1) and the unsaturated compound (2).
The organic compounds of cobalt suitable for the present invention are not of a special structure, but generally known organic acid salts of cobalt, such as cobalt naphthenate and cobalt octylate, are sufficient and have sufficient solubility in a suitable solvent. For example, chelating compounds such as acetylacetonate of cobalt can be used.

The amount of the organic compound of cobalt used is (1)
The total of the polymer of the component and the unsaturated compound of the component (2) is 10
0.005 to 0 parts by weight of cobalt organic compound
It is 5 parts by weight, more preferably 0.05 to 0.5 part by weight. If the amount of the organic compound of cobalt is less than 0.005 parts by weight, the curability becomes insufficient. On the other hand, if the amount of the organic compound of cobalt is more than 5 parts by weight, the effect of increasing the addition is not observed. However, only the hue deteriorates.

The composition of the present invention comprising the components (1), (2) and (3) is cured in a short time by heating at a temperature of 80 ° C. or more, more preferably 100 ° C. to 200 ° C. It can be made of resin and can be used in various fields.

When the coating composition of the present invention is put into practical use, organic or inorganic reinforcing materials, fillers, coloring agents, release agents, waxes, modifying polymers, oligomers, Of course, a plasticizer or the like can be used in combination.

[0030]

EXAMPLES Next, examples will be shown below to facilitate understanding of the present invention.

Example 1 Synthesis of polymer (A) having acetoacetyl group in side chain In a 2-liter separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas inlet tube, 214 g of acetoacetylethyl methacrylate, cyclohexyl 160 g of methacrylate, 7 g of acrylic acid, 4 g of azobisisobutyronitrile and 380 g of toluene were charged, and polymerization was carried out at 75 to 80 ° C. for 8 hours under a nitrogen stream. Next, 4 g of azobisisobutyronitrile was added and polymerization was carried out for an additional 8 hours. Polymerization rate by solvent evaporation is almost 99%, slightly yellow, viscosity 7.9 poise, number average molecular weight 18,000 and weight average molecular weight 55,000 by GPC measurement.
A toluene solution of (A) was obtained.

To 100 parts by weight of a toluene solution (50% solid content) of the polymer (A) was added tris (2-hydroxyethyl) represented by the following structural formula as a polyfunctional acrylate.
Triacrylate of isocyanuric acid (Hitachi Chemical Co., Ltd.)
FA-731A)

Embedded image 18 parts by weight (acetoacetyl group / F of polymer (A))
A-731 has an acryloyl group ratio of about 1/1) and 0.1 part by weight of cobalt octylate (cobalt content: 8%) to form a homogeneous solution.
0 parts by weight were added to obtain a composition.

This composition was coated on a bonderite steel sheet so that the dry coating thickness was 50 μm. After left overnight at room temperature, it was dried at 60 ° C. for 1 hour and then cured at 150 ° C. for 30 minutes. Although the obtained cured coating film was slightly yellowish, its hardness was 4H, and the adhesion test was 100/1.
At 00, a very hard coating film having good adhesion was obtained. The gloss reflectance of the cured coating film surface was 88%. The coating film immersed in methyl ethyl ketone for 15 minutes showed no abnormality at all. On the other hand, the hardness of the coating film without cobalt octylate was H to 2H, and it was dissolved immediately after immersion in methyl ethyl ketone, and after 15 minutes, no solid coating film remained.

Example 2 Synthesis of polymer (B) having acetoacetyl group in side chain A 1-liter separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas inlet tube was charged with 300 styrene.
g, 70 g of acetoacetylethyl methacrylate, 3 g of acrylic acid, 370 g of methyl ethyl ketone, 4 g of azobisisobutyronitrile, and 2 g of lauryl mercaptan. 2 g of lonitrile was added and polymerization was carried out for 6 hours. The polymerization rate by solvent evaporation was almost 99%, and a solution of polymer (B) in methyl ethyl ketone having a pale yellow color, a viscosity of 5.4 poise, a number average molecular weight of 16,000 and a weight average molecular weight of 51,000 was obtained.

Synthesis of bromo vinyl ester (C) YDB-400 manufactured by Toto Kasei Co., Ltd. as a bromo epoxy resin in a 1 liter separable flask equipped with a stirrer, reflux condenser, thermometer and gas inlet tube. 64
0 g, methacrylic acid 172 g, hydroquinone 0.3
g, 4 g of triethylamine, and 13 g under nitrogen stream.
After a reaction at 0 to 135 ° C. for 3 hours, the acid value became substantially zero. A bromovinyl ester (C) having a dark reddish brown color and a melting point of about 60 ° C. was obtained.

Polymer (B) methyl ethyl ketone solution (about 50% solid content) 200 parts by weight Bromyl vinyl ester (C) 135 parts by weight Cobalt acetoacetate 0.3 parts by weight Methyl ethyl ketone 150 parts by weight is uniformly dissolved to obtain a composition. I got The ratio of the acetoacetyl group of the polymer (B) to the methacryloyl group of the bromovinyl ester (C) is approximately 1: 1. This composition was mixed with a glass cloth (WBA-18K-105, manufactured by Nitto Boseki Co., Ltd.).
-RB · 84), dried at room temperature, and left at 60 ° C. for 30 minutes. The obtained prepregs are placed on a hot plate at 80 ° C. in a uniform number so as to have a thickness of 1.6 m / m, and the temperature is increased to 150 ° C. in 30 minutes under a pressure of 50 kg / cm ² and cured for 1 hour. Was. The obtained laminate had flame retardancy equivalent to UL standard VO, and the electrical properties were excellent as shown in Table 1.

[0037]

[Table 1] Flexural strength 48.1 kg / mm ² Flexural modulus 1910 kg / mm ² Copper foil peel strength 1.5 kg / cm Solder heat resistance 260 ° C, after 60 seconds No change in appearance Heat resistance 170 ° C × 1 hour No change Chemical resistance 3N-NaOH (40 ° C / 3 minutes) No change Trichlorethylene resistance Boiling 5 minutes No change

[0038]

Since the curable composition of the present invention is constituted as described above, it is stable with one liquid, cures quickly by heating, and does not impair water resistance and various electrical properties. It shows the coating film properties and weather resistance.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ identification code FI C09D 4/06 C09D 4/06 (58) Field surveyed (Int.Cl. ⁶ , DB name) C09D 133/14 C08J 3/24 CER C08K 5/00 C08L 33/14 C08L 101/02 C09D 4/06

Claims (6)

(57) [Claims] 1. A (1) obtained by polymerizing or copolymerizing a monomer having an unsaturated group and acetoacetyl group in a molecule, Sutaira having two or more acetoacetyl groups in the molecule
A polymer having an average molecular weight of 1,000 to 100,000 ,
(2) An unsaturated compound having two or more (meth) acryloyl groups in one molecule, and (3) an organic compound of cobalt with respect to 100 parts by weight of the total amount of (1) and (2)
Curable characterized by containing 0.005 to 5 parts by weight
Compositions for paints . 2. The polymer having two or more acetoacetyl groups in one molecule of the component (1) is a polymer obtained by copolymerizing acetoacetylalkyl (meth) acrylate and a monomer copolymerizable therewith. A curable coating composition according to claim 1. 3. The polymer having two or more acetoacetyl groups in one molecule of the component (1) is a polymer obtained by copolymerizing acetoacetylethyl (meth) acrylate and a monomer copolymerizable therewith. A curable coating composition according to claim 1. 4. The method according to claim 1, wherein the unsaturated compound as component (2) is trishydroxyethyl isocyanurate tri (meth) acrylate or (bromine-containing) epoxy resin having at least two epoxy groups in one molecule. The curable coating composition according to claim 1, which is a (bromine-containing) vinyl ester resin obtained by reacting 5. The curable coating composition according to claim 1, wherein the organic compound of cobalt as the component (3) is an organic salt of cobalt or acetylacetonate of cobalt. 6. The use ratio of a polymer having two or more acetoacetyl groups in one molecule of the component (1) to an unsaturated compound of the component (2) is one to one acetoacetyl group of the polymer of the component (1). The curable coating composition according to any one of claims 1 to 5, wherein the unsaturated compound as the component (2) has two or less (meth) acryloyl groups.