JPS5834869A - Resin composition for powder coating - Google Patents

Abstract

PURPOSE:To provide a resin compsn. for powder coating containing a specified polyester and a (beta-methyl)glycidyl group-contg. vinyl polymer and excellent in film properties, appearance and weathering resistance. CONSTITUTION:Additives such as pigment, filler, flow modifier and catalyst are added to a mixt. of (A) 60-97wt% polyester with an acid value of 20- 200mgKOH/g, a softening point of 80-150 deg.C (ring & ball method) and a number- average molecular weight of 1,000-10,000 and (B) 40-3wt% (beta-methyl) glycidyl group-contg. vinyl monomer with a number-average molecular weight of 300- 5,000 obtained by esterification and polymerization of 20-99wt% (beta-methyl)glycidyl (meth)acrylate, 0-50wt% other vinyl monomers (e.g., methyl methacrylate) and 1-30wt% monobasic acid (e.g., benzoic acid). The mixt. is melt kneaded and is crushed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel and useful resin composition for powder coatings, and more specifically, as essential components,
The present invention relates to a composition containing each specified polyester and a (β-methyl)glycidyl group-containing vinyl polymer.

Since it does not have the same properties as conventional polyester resins containing carzexyl groups and is also inferior to l111m, no practical product has yet been found.

However, as a result of intensive research in view of these actual circumstances, the present inventors discovered that vinyl polymers containing (β-methyl) glycidyl groups modified with basic acids having a specific molecular weight (hereinafter referred to as mono-K polymers) "Glycidyl group-containing vinyl polymer"
Also called. )V When used as a curing agent for the polyester resin, we have discovered the resin composition e#IJ for powder coatings, which has excellent not only compatibility but also the physical properties, appearance, and weather resistance of the resulting coating film. , we have completed the original @.

That is, the present invention has an acid value of 20 to 200 ■KOH/11
Polyester (
60 to 97% by weight of 4), -3 to 40% by weight of (β-methyl glycidyl group-containing vinyl polymer (up to)) having a number average molecular weight of 300 to 000 modified with a basic acid, and t,
The present invention provides a resin composition for powder coatings containing as an essential component.

Here, the polyester (transformed) which is the first component of the composition of the present invention has an acid value of 20 to 200 daKO/l.
, preferably 25 to 70 MgKOH/, 9, softening point (
Ring and ball method → 80-150℃, preferably 100-130℃
℃, and the number average molecular weight is within the range of 00 to IQOOO1, preferably 2,000 to 000, and as long as it is within this range, even if it has a branched structure, It may also have a similar structure.

There is no particular restriction on the method for producing the polyester (4), and well-known and commonly used methods can be applied as they are, and the acid component and alcohol component are also well-known and commonly used dibasic acids and dibasic acids. In addition to the above polybasic acids, dihydric alcohols and trihydric alcohols or higher polyhydric alcohols can be used. Therefore, to list only typical acid components and alcohol components, the acid components include terephthalic acid, isophthalic acid, 7-thalic acid, methyl terephthalic acid, trimellitic acid, pyromellitic acid, and their Anhydride; or adipic acid, sepacic acid, amber, maleic acid, 7
Malic acid, tetrahydro-tetraphthalate J4/acid, methyl-tetrahydro-phthalic acid, hexahydrophthalic acid, methyl-hexahydro-7-thalic acid and their anhydrides, etc., while the alcohol component is ethylene. Glycol, Globilengly H-, Jk, 1. 5-7F tandiol,
1.4-butanediol, 1.6-hequinanediol,
Neopentyl glycol, bishydroxyethyl terephthalate), water 1! bisphenol, ethylene oxide adduct or propylene oxide adduct of hydrogenated bisphenol A, trimethylolethane, trimethylolpropane, glycerin, pentaerythritol and 2,2.4-)dimethylpentane-1,3-diol, etc. In addition, it can be used as one of the recall components of the monoepoxy compound.

On the other hand, the glycidyl group-containing vinyl polymer modified with the above-mentioned bases, which is the second component of the composition of the present invention, has a number average molecular weight of 00 to 00 U, preferably 500 to 0.
00, containing 20-99% by weight of (β-methyl)glycidyl (meth)acrylate, preferably 40-78% by weight, and 0-1% of other vinyl monomers.
50 weight tn, preferably 20-40% by weight, -basic acid 1
It is obtained from ~50% weight, preferably 2~20% weight.

There is a method of esterifying and polymerizing diyl (meth)acrylate and a monobasic acid, or a method of coexisting K (β-methyl → glycidyl (meth)acrylate and a monobasic acid during polymerization to perform esterification and polymerization at the same time. Furthermore, a method of adding a monobasic acid to esterify after the completion of polymerization can be applied.

If the molecular weight of such a polymer is lower than 300, the mechanical strength of the resulting coating film will be insufficient, and smoke will be emitted when the coating film is baked. It is unsuitable in either case, as it not only results in poor stretchability or smoothness, but also poor compatibility between the resins, making it impossible for the crosslinking reaction to proceed sufficiently, resulting in poor coating film strength. It is.

In addition, if the amount of (β-methyl)glycidyl (meth)acrylate is less than 20% by weight, the compatibility with the polyester (A) will be poor, and the reaction with the polyester (A) will be insufficient. Therefore, it is not possible to provide a good cured coating film.

Such (β-methyl)glycidyl (meth)acrylates include L glycidyl acrylate, glycidyl methacrylate, β-methylglycidyl acrylate and β
-Methylglycidyl methacrylate.

Then, for this (β-methyl)glycidyl (meth)acrylate, its copolymerization component [vinyl monomers that may be used include styrene, (meth)acrylic acid ester, hexamaric acid diester, acrylonitrile, and acrylamide]. Typical examples include <K, this (
Among the meth)acrylic acid esters, methyl methacrylate and seIsolp methacrylate are polyesters)
% is preferable because it has excellent compatibility with.

Of course, in addition to these materials, any material that can be copolymerized with scissors glycidyl (meth)acrylate can be used. - In addition, the monobasic acid used for modifying the glycidyl group-containing glycidyl group-containing vinyl polymer is also a component for improving MS properties with polyester (A), and when the amount is less than 1 part by weight, There is no effect of introducing it, and on the other hand, if it exceeds 30% by weight, the weather resistance of the resulting product will be poor, so it is not suitable.

As such a basic acid, any of aromatic, aliphatic or alicyclic acids can be used, but IIIJII
Smoothness of I.

From the viewpoint of gloss and sharpness, aliphatic basic acids are particularly preferred. -Basic acids include benzoic acid, paratertiary butylbenzoic acid and hydrogenated products thereof, caproic acid, capric acid, lauric acid, chrystic acid,
It is a matter of detail that palmitic acid, stearic acid, arachidic acid, behenic acid, etc., and those that have been esterified or etherified with t- remaining, resulting in -basic acids, can also be used.

There are no particular restrictions on the method for producing the polymerization-i, and any well-known and commonly used method can be applied as is, but a solution polymerization method is particularly recommended because of its ability to easily adjust the molecular weight.

The resin composition of the present invention contains each of the above-mentioned polyesters, - a glycidyl group-containing vinyl polymer modified with a basic acid), and the ratio of these two components used is 60 to 97%. parts and 3 to 4 os, preferably 70 to 90 parts to 10 to 30 parts.

The composition of the invention thus obtained contains pigments or other fillers, flow modifiers such as 2-ethylhexyl acrylate polymers or silicones, optionally amines,
Various catalysts such as indazole or metal soap or other additives are blended, then kneaded using an extruder or the like, and then pulverized to form a powder coating.

Known methods such as electrostatic coating, fluidized dip coating, and the like can be employed as the powder coating method for vehicle decoration.

Next, the present invention will be specifically explained with reference to Examples, where all parts are by weight.

Reference example 1 (Preparation example of polyester) Neopendel glycol 2.04916°dimethyl terephthalate $911115
A mixture consisting of 11 parts of zinc acetate and 11 parts of zinc acetate was gradually heated to 210°C while removing the generated methanol from the system, and then 67 parts of adipic acid, 1,575 parts of terephthal 9, and t5 of dimethyltin oxide were added. do,
It took 10 hours to raise the temperature to 240°C, and then the temperature of the reactant t' was lowered to 180°C.
330iSt plus acid value s5, softening point 1
A polyester having a temperature of 26° C. and a number average molecular weight of 000 was obtained. This is referred to as "polyester (mu-1)".

Reference Example 2 (Same as above) A mixture consisting of 951 parts of neopentyl glycol, 566 parts of ethylene glycol, 1,856 parts of dimethyl teresterol, and 1,856 parts of zinc acetate was gradually added while removing the methanol produced from the system. After raising the temperature to 210°C, 1570 parts of In7tal Shun dibutyltin oxide 211 was added, and the temperature was raised to 240°C over 10 hours, and the reaction was continued at the same temperature to obtain an acid value of 25 and softening. A polyester V having a temperature of 105° C. and a number average molecular weight of 700 was obtained. This is referred to as Y[polyester (Mu-2)].

Reference Example 5 ← Preparation example of glycidyl group-containing vinyl polymer modified with basic acid) β-Methylglycidyl methacrylate 15 parts Glycidyl methacrylate 40# Methyl methacrylate 40 parts t-Butyl perbenzoate 1 Ikuoyohikumene hydroperoxide (A mixture of 5 parts of L was polymerized under pressure at 150°C with 1,00 parts of xylene and 5 mK of 2,2-diethylhexanoic acid, and after removing the middle silane, the number average molecular weight was 1500 and the epoxy equivalent was is 2
A polymer of No. 90 was obtained. This is called “polymer (B-1)”
Let it be J.

Reference Example 4 (Same as above) A mixture of β-methylglycidyl methacrylate 20 parts glycidyl methacrylate 4-7a sorp methacrylate 35 parts t-butyl perbenzoate 2 parts @, 100 parts of xylene at 155°C and 2.2 parts of melon tylhexane [ After polymerization by dropping xylene into 5 parts, a polymer having a number average molecular weight of t600 and an epoxy equivalent of 270 was obtained. This is called “Polymerization @ (B-February).

Example 1 85 parts of the polyester (Im-1) obtained in Reference Example 1 and 15 parts of the polymer (Im-1) obtained in Reference Example 3 were further added with titanium oxide 50s and "Akuto Nar 4FJ".
1 part of <W4 Bayer Germany JIR dynamic control agent) was added and mixed, and then kneaded in an extruder [After cooling, it was crushed to obtain a powder coating.

Next, after applying this paint to a mild steel plate,
After baking at 0 for 20 minutes, an Ill film was obtained.

Example 2 Same as Example 1 except that 89 parts of the polyester (Mu-2) obtained in Reference Example 2 and 11 parts of the polymer ('B-1) obtained in Reference Example 4 were used. A coating film was obtained.

Example 3 Polyvarnish of Reference Example 1, Chill (Mu-1) 83 parts and Reference Example 4
Example 1 except that 17 parts of polymer (B-2) of
A coating film was obtained in the same manner as above.

The performance of the coating films obtained in each example is summarized in Table 1 K, and all of them are excellent in appearance, mechanical strength, and weather resistance. Ta.

Claims (1)

[Scope of Claims] France) An acid value of 20 to 200 WKOa/# and a softening point of 80
~150°C and a number average molecular weight of too 0~I
Q, 000 polyester 60-97 weight - and (
II) - A glycidyl group- or β-methylglycidyl group-containing vinyl polymer modified with a basic acid and having a number average molecular weight of 300 to 1,000 by weight - 5 to 40 weight - Resin for powder coatings comprising as an essential component Composition.