JPS5824465B2 - Hunting plant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermosetting resin composition for powder coatings that can form a coating film with a smooth coating surface and excellent salt resistance and mechanical strength.

When a polymer having a (methyl)glycidyl group is used as a base resin for a powder coating, it is conceivable to use an aliphatic dibasic acid such as sebacic acid as a curing agent.

However, because the above polymer and aliphatic dibasic acid have poor compatibility, the coating film obtained from the powder coating of the composition lacks smoothness and gloss, and has poor salt resistance and mechanical strength. There is.

In view of these points, as a result of intensive research, the present inventor introduced a polyester containing a hydroxyl group into a polymer containing a (methyl)glycidyl group, and by using an amino resin and a polyvalent carboxy compound as a curing agent. It was discovered that the above-mentioned drawbacks could be improved, and the present invention was developed.

That is, the present invention relates to a polymer (hereinafter referred to as a glycidyl polymer) consisting of a vinyl monomer having a (methyl)glycidyl group, a polymerizable unsaturated polyester, and another vinyl monomer.
The present invention relates to a thermosetting resin composition for powder coatings, which contains an amino resin and a polyvalent carboxy compound.

To explain in detail the performance of the composition of the present invention, since the glycidyl polymer contains a polyester skeleton, this polyester acts as an internal flow agent for the glycidyl polymer, so that a smooth coating surface can be obtained. Furthermore, since it significantly improves the compatibility between the glycidyl polymer and the polycarboxylic compound, a coating film with excellent gloss can be obtained.

In addition, an auxiliary curing reaction occurs between the hydroxyl groups of the polyester in the glycidyl polymer constituting the composition of the present invention and the methylol groups in the amino resin constituting the composition of the present invention, resulting in gloss and flexibility. , it has extremely excellent salt resistance.

These excellent effects are due to the polyester skeleton contained in the glycidyl polymer and the reaction between the hydroxyl group of the polyester and the amino resin, and are simply due to the reaction of the amino resin with the polyester skeleton contained in the glycidyl polymer, and the polymers containing (methyl)glycidyl groups, amine resins, polyester resins, etc. The coating film obtained from a four-component mixed composition of a polyvalent carboxylic compound and a polyester was significantly inferior in terms of smoothness, sharpness, and mechanical strength.

The vinyl monomer having a (methyl)glycidyl group, which is the first component i of the glycidyl polymer used in the present invention, refers to a vinyl monomer having a glycidyl group and/or a vinyl monomer having a methylglycidyl group. Examples include (methyl)glycidyl ester of (meth)acrylic acid, di(methyl)glycidyl ester of maleic acid, fumaric acid, itaconic acid, etc., (methyl)glycidyl ether of (meth)allylic alcohol, and the like.

One or more of these may be contained in the copolymer in an amount of 5 to 40% by weight (hereinafter simply expressed as %), but in order to obtain a coating film with particularly excellent appearance and physical and chemical performance. For this purpose, it is appropriate to use 5-20% of the monomer having a glycidyl group and 5-20% of the monomer having a methylglycidyl group.

The polymerizable unsaturated polyester used in the present invention as the second component can be produced by a known method.

Generally, a manufacturing method is used in which a component containing an unsaturated group, an acid component, and an alcohol component are subjected to a condensation or addition reaction.

Among the raw materials used, unsaturated components include, for example, fumaric acid, maleic acid (anhydride), itaconic acid, etc., and acid components include, for example, e"m"p-phthalic acid and its lower alkyl esters, trimellitic acid, These include pyromellitic acid, adipic acid, sepacic acid, benzoic acid, etc., and alcohol components include, for example, glycerin, ethylene glycol, propylene glycol, neopentyl glycol, pentaerythritol, trimethylolpropane, and trimethylolethane.

The hydroxyl value of polymerizable unsaturated polyester is 20-300
KOH7V/? (units will be omitted hereafter) and the acid value is 5 K.
OH■/1 (Hereafter, the unit will be omitted.

), and if the acid value is too large, exceeding 5, it is not preferred because gelation tends to occur during the production of glycidyl polymers or during heating and kneading for the preparation of powder coatings.

Furthermore, if the hydroxyl value is less than 20, the physical properties of the coating film will be poor, and if it exceeds 300, the chemical resistance will be poor, which is not preferred.

As the other vinyl monomer, which is the third component, it is appropriate to use one that does not react with the (methyl)glycidyl group, or one that has poor reactivity at the temperature during polymerization or crosstalk.

Examples include (meth)acrylic acid esters such as methyl methacrylate, butyl methacrylate, β-hydroxyethyl methacrylate, styrene, vinyltoluene, acrylonitrile, vinyl acetate, vinyl chloride, and the like.

The appropriate amount of these monomers to be used is in the range of 20 to 90%.

The glycidyl polymer used in the present invention can be obtained by a well-known method such as solution polymerization of each of these components, removing the solvent, suspension polymerization, or bulk polymerization, and then collecting a granular polymer. .

Its preferable number average molecular weight is 3000-30000, more preferably 5000-15000, and its preferable ring and ball softening point is 70-150°C, more preferably 90-1
The temperature is 20°C.

The amino resin in the composition of the present invention includes melamine, urea,
Examples include amine compounds such as guanamine methylolated with formalin, alkyl etherified products thereof, and cocondensates thereof, and preferred ones include hexamethoxymethylmelamine, tetrabutoxymethylbenzoguanamine, and the like.

The polyvalent carboxy compounds in the composition of the present invention include, for example, maleic acid, fumaric acid, succinic acid, adipic acid, sepacic acid, azelaic acid, decanedicarboxylic acid, phthalic acid, trimellitic acid, and pyromellitic acid. There is an anhydrous form of carvone brewing.

Also, polyester having two or more carboxyl groups,
Alternatively, the hydroxyl groups that produce such polyester during baking can be
A mixture of a polyester and an acid anhydride having more than one polyester can also be used as the polyvalent carboxy compound.

The main curing reaction of the composition of the present invention is a reaction between the (methyl)glycidyl group of the glycidyl polymer and the carboxyl group of the polyvalent carboxy compound, and the preferable ratio is the number of (methyl)glycidyl groups in the glycidyl polymer. and the carboxyl group of the polyvalent carboxy compound: 1 = 5 to 5:
1, more preferably 1:2 to 2:1.

The amount of amino resin used is usually 2-25%, more preferably 2-15%, based on the glycidyl polymer.

Various acids, alkalis, amines, etc. can be added to the composition of the present invention in order to accelerate or suppress the curing reaction, and long-chain alkyl esters of acrylic acid with a softening point of 50°C or less can be added to improve the smoothness of the coated surface. Polymers, fluoropolymers, cellulose acetate butyrate, and epoxy resins can be added.

A powder coating material can be prepared from the composition of the present invention by any known method.

The resulting powder coating can be applied by any known method such as electrostatic spraying or fluidized dipping.

The present invention will be explained below according to examples.

"Parts" in the text indicate parts by weight.

[Polyester A]

410 parts of isophthalic acid, 110 parts of trimethylolethane, 250 parts of 1.6 hexanediol, nothing.

14 parts of hydromaleic acid was heated at 180°C for 2 hours, then at 220°C for about 8 hours while stirring in an inert gas stream,
A polyester having a softening point of 95° C., a hydroxyl value of 120, and an acid value of 2 was obtained.

[Polyester B]

350 parts of dimethyl terephthalate, 40 parts of adipic acid,
90 parts of trimethylolpropane, 200 parts of neopentyl glycol, 8 parts of maleic anhydride, and 0.5 parts of zinc acetate were added, and while the methanol produced was removed from the system, 1
After raising the temperature from 50°C to 210°C over 7 hours, the temperature was maintained at 210°C and 2 mmHg for 2 hours to obtain a polyester having a softening point of 97°C, a hydroxyl value of 125, and an acid value of 1.3.

Example 1 To a mixture of 200 parts of water and 3 parts of triammosine phosphate heated to 50°C, 2 parts of calcium acetate and 0.5 parts of sodium sulfite were added with stirring, and then the mixture was heated to 60°C and heated in a nitrogen stream. 40 parts of styrene, 30 parts of polyester A, 10 parts of glycidyl methacrylate, 10 parts of methylglycidyl methacrylate, 20 parts of isobutyl methacrylate, 4 parts of azobisisobutyronitrile, 1 part of tert-butyl perbenzoate, 1 part of n-lauryl mercaptan. was added and held at the same temperature for 3 hours, then gradually raised to 80°C, and further held at the same temperature for 15 hours to obtain the product.

was separated, washed with water and dried to give a softening point of 110°C and a molecular weight of 83.
000 polymer was obtained.

81 parts of the above polymer, 14 parts of 1.10 decane dicarboxylic acid, 5 parts of Nilakaratsuk MW-100 (melamine resin manufactured by Sansho Chemical Co., Ltd.), 0.5 part of Modaflow (flow control agent 4 manufactured by Monsando), and oxidation After kneading 50 parts of titanium at 100° C. for 3 minutes using a heated triple roll, the mixture was separated using a 150-mesh wire gauze to obtain a powder having a mesh size of 150 mesh or less.

This powder was applied to a mild steel plate by electrostatic spray coating and baked at 200° C. for 20 minutes to obtain a coating film.

Example 2 Example 10 75 parts of polymer,
0 (epoxy resin manufactured by Inu Nippon Ink Chemical Industry Co., Ltd.)
Using 5 parts, 0.5 parts of Modaflow, and 50 parts of titanium oxide,
Thereafter, a baked coating film was obtained in the same manner as in Example 1.

Example 3 35 parts of styrene, 30 parts of polyester A, 7 parts of glycidyl methacrylate, 8 parts of methylglycidyl methacrylate
A polymer having a softening point of 105° C. and a molecular weight of 81,000 was obtained in the same manner as in Example 1 using 20 parts of inbutyl methacrylate.

81 parts of the above polymer, 9 parts of 1.10 decanedicarboxylic acid,
A coating film was baked in the same manner as in Example 1 using 10 parts of Nirakaratsuk MW-100, 0.5 parts of Modaflow, and 50 parts of titanium oxide.

Comparative Example 1 Exactly the same operation was repeated except that the entire amount of polyester A in Example 1 was replaced with isobutyl methacrylate, and the entire amount of methyl glycidyl methacrylate was replaced with glycidyl methacrylate, and a softening point of 101'C1 molecular weight of 9 was obtained.
5000 polymer was obtained.

A baked coating film was obtained in the same manner as in Example 1 using 86 parts of the above polymer, 14 parts of 1.10 decanedicarboxylic acid, 0.5 parts of Modaflow, and 50 parts of titanium oxide.

; Comparative Example 2 68 parts of the polymer of Comparative Example 1, 11 parts of 1.10 decane dicarboxylic acid, 16 parts of polyester A, Nirakaratsu MW-1
A baked coating film was obtained in the same manner as in Example 1 using 0.05 parts of Modaflow, 0.5 parts of Modaflow, and 50 parts of titanium oxide.

The performance of the coatings obtained on each side is shown in Table 1.

Claims (1)

[Claims] 1 Vinyl monomer having glycidyl group and/or methylglycidyl group 5-40% by weight, acid value 5 KOH~
A polymer obtained by polymerizing 5 to 40% by weight of a polymerizable unsaturated polyester with a hydroxyl value of 20 to 300 KOHη/g and 20 to 90% by weight of other vinyl monomers, an amine resin and a polycarboxylic A thermosetting resin composition for powder coatings, which is made by blending compounds.