JPS60120764A - Powdered paint resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which gives a coating film having excellent physical properties, weather resistance and appearance, consisting of a polyester resin, a specified polymer and a blocked isocyanate. CONSTITUTION:20-100wt% at least one compd. selected from among glycidyl (meth)acrylate and beta-methylglycidyl (meth)acrylate and 80-0wt% other vinyl monomer such as methyl methacrylate are copolymerized to obtain a (beta-methyl) glycidyl group-contg. polymer (B) having a number-average MW of 300-5,000. 60-96wt% polyester resin (A) having a number-average MW of 1,000-10,000, an acid value of 100mgKOH/g, a hydroxyl value of 5-100mg KOH/g and a softening point of 80-150 deg.C, 5-40wt% component B and 1-20wt% blocked isocyanate (C) such as xylylene diisocyanate are melt-kneaded and crushed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and useful resin composition for powder coatings, and more particularly, the present invention relates to a new and useful resin composition for powder coatings, and more particularly, it is composed of a specific polyester resin, a specific polymer, and a blocked isocyanate, and is particularly suitable for coating films. This invention relates to a resin composition with excellent physical properties, appearance, weather resistance, etc.

Powder coatings composed of general K, carboxyl group-containing polyester resins and acrylic resins have poor compatibility with these resins, and powder coatings with such compositions do not have a bath melt flow when applied and baked. From a place where sexuality is insufficient,
The cured coating film thus obtained has the disadvantage of not exhibiting sufficient physical properties and appearance.

However, as a result of intensive research in view of the existence of such shortcomings in the conventional technology, the present inventors discovered that (β-methyl)glycidyl (meth)acrylate is an essential monomer in a polyester resin having both a carboxyl group and a hydroxyl group. When a polymer with a specific molecular weight range and a blocked isocyanate are used in combination, not only do these components have good compatibility, but the cured coating film obtained from the powder coating with this combination has improved physical properties and weather resistance. The present invention was completed based on the discovery that the coating film has excellent properties as well as the appearance of the coating film.

That is, the present invention has an acid value of 5 to 100 as an essential component.
mgKOI (72C or less, the unit is omitted and only the numbers are written), and the hydroxyl value is 5 to 100, 9KOH/IC
(same as above), a softening point of 80 to 150C, and a number average molecular weight (Mn) of i, oo.

~io, ooo polyester resin (A) 60~9
6 parts by weight of one or more compounds selected from the group consisting of glycidyl acrylate (GA), glycidyl methacrylate (GMA), β-methylglycidyl acrylate (MGA), and β-methylglycidyl methacrylate (MGMA). Stones obtained from 100 weight i% and other vinyl monolayers from 0 to BO heavy lids are 300~
For a powder coating comprising 3 to 40 parts of a polymer (B) containing 5,000 (β-methyl)glycidyl groups and 1 to 20 parts by weight of blocked isocyanate CC) A resin composition is provided.

Here, the aforementioned polyester side 11 & (A) each have an acid value of 5 to 100, preferably 10 to 70.
and has a hydroxyl value of 5 to 100, preferably 10 to 70, and a softening point of 80 to 150 tl:', preferably 100 to 70.
160C and 1 stone. OD O~io, ooo,
Preferably, the number is 2,000 to 5,000, but as long as it falls within this range, it may have a branched structure or a linear structure.

As for the method for preparing the polyester side 1 bacteria (A), there are no particular limitations, and well-known and commonly used methods can be applied as they are, and both the acid and alcohol components are well-known and commonly used. Dibasic acids, tribasic acids and higher polybasic acids, and dihydric alcohols and trihydric alcohols and higher polyhydric alcohols can be used.

Therefore, to cite only representative acid components and alcohol components, the acid components include terephthalic acid, isophthalic acid, phthalic acid, methylterephthalic acid, trimellitic acid, pyromellit U, and their anhydrides. substance; or adipic acid, sebacic acid,
Succinic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, methyl-gutrahydrophthalic acid, hexahydrophthalic acid/1/cough, methyl-hexahydrophthalic acid and their anhydrides, etc., while alcohol components include Ethylene glycol, propylene glycol, 1.3-butanediol, 1.4-)tanediol, 1.6-hexanediol, neopentyl glycol, bishydroxyethyl terephthalate, hydrogenated bisphenol A1 Ethylene oxide to hydrogenated bisphenol Adducts or propylene oxide adducts, trimethylolethane, trimethylolethane, chrycerin, pentaerythritol and 2.2.4-trimethylpentane-1,6
-diol, etc. Furthermore, monoethoxy compounds can also be used as one of the glycol components.

Next, the above-described (β-methyl)glycidyl group-containing polymer CB) is one in which i is in the range of 600 to 5,000, preferably 500 to 5,000, and includes glycidyl acrylate and glycidyl methacrylate. , one or more (β-methyl) selected from β-methylglycidyl acrylate and β-methylglycidyl methacrylate
20 to 100 weights of glycidyl (meth)acrylate
The weight of the vinyl monomer is preferably 40 to 80% by weight, and preferably 20 to 60% by weight of other vinyl monomers.

If the molecular violet of such a polymer is lower than 600, the mechanical strength of the resulting coating film will be insufficient, and smoke will be emitted when the coating film is baked; conversely, if it exceeds 5,000, the resulting coating In either case, not only will the clarity or smoothness of the film be poor, but also the compatibility between the resins will be poor, making it impossible for the crosslinking reaction to proceed sufficiently, resulting in a decrease in the strength of the paint film. It's inappropriate.

If the content of (β-methyl)glycidyl (meth)acrylate is less than 20% by weight, the compatibility with the polyester resin 1111 (A) will be poor, and the reaction with this polyester resin (A) will deteriorate. As a result, a cured coating film of Good 1 cannot be obtained.

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

And, for such (β-methyl)glycidyl (meth)acrylate, it may be used as its copolymerization component.As the other vinyl monomers, these (β-
Typical examples include (meth)acrylic esters excluding methyl)glycidyl(meth)acrylate, (meth)acrylonitrile, (meth)acrylamide, fumaric acid diester, maleic acid diester, itaconic acid diester, and styrene. However, among these (meth)acrylic acid esters, methyl methacrylate and seronlup methacrylate are particularly suitable because they have excellent compatibility with the polyester a (tlm (A)).

It goes without saying that in addition to this, any material can be used as long as it can be copolymerized with the glycidyl (meth)acrylate.

There are no restrictions on the method for producing the homogeneous polymer (B), and well-known methods can be applied as they are, but the mortar method is particularly recommended because it is easy to adjust the molecular needle. Ru.

Further, typical blocked isocyanates CC) include those contained in additives of aliphatic, aromatic or cycloaliphatic isocyanates such as xylylene diisocyanate, isophorone diisocyanate or hexamethylene diisocyanate and active hydrogen compounds. Free isocyanate groups are blocked with known and commonly used blocking agents such as methanol, inglonoQnol, butanol, ethyl lactate or ε-caprolactam, and typical active hydrogen compounds include ethylene glycol. , butylene glycol, trimethylolpronochloride, chrycerin, ethylene diamine or hexamethylene diamine, and various high molecular weight substances such as polyol, polyether, polyester or polyamide.

Therefore, the composition of the present invention contains the respective components of the polyester resin (A), (β-memethy]glycidyl group-containing polymer CB), and blocked incyanate (C) as listed above. Or, the usage ratio of each of these components is 60-96:3-40:1120,
Preferably, a range of 60 to 90 to 30 to 6 to 10 is suitable.

The composition of the present invention thus obtained may further contain pigments or other fillers, flow regulators such as 2-ethylhexyl acrylate polymer or silicone, if necessary.
In some cases, various catalysts such as amines, imidazoles or organotin compounds, or various glue resins such as epoxy resins or petroleum resins may also be blended. The mixture is kneaded using a known and commonly used mixer such as a mill, and then pulverized to form a powder coating.

As the powder coating method, known and commonly used methods such as electrostatic coating or fluidized dip coating can be applied as they are.

Next, the present invention will be specifically explained with reference to Reference Examples, Examples, and Comparative Examples. In the following, "part" means "part by weight" unless otherwise specified.

Reference Example 1 [Preparation example of polyester resin (A)] A mixture consisting of 344 parts of ethylene glycol, 1.348 parts of neopentyl glycol, 1.796 parts of dimethyl terephthalate, and 1.8 parts of zinc acetate was charged and produced. Gradually remove methanol from the system at 210C.
After adding 596 parts of terephthalic acid, 740 parts of isophthalic acid, 80 parts of adipic acid and 2 parts of diptyltin oxide, the temperature was increased to 24% over 10 hours.
The temperature was raised to 0C.

Next, the temperature of the obtained reaction product was lowered to 18 DC, 136 parts of trimellitic anhydride was added, and the reaction was further continued at the same temperature to obtain an acid value of 24, a hydroxyl value of 14, and a softening point of 114C. A polyester resin (A) having a molecular weight of 4,000 was obtained. Hereinafter, this will be abbreviated as resin (A-1).

Reference example 2 (same as above) 3369 parts of ethylene glycol, 1,316 parts of neopentyl glycol, 1.75 parts of dimethyl terephthalate
A mixture consisting of 2 parts of zinc acetate and 1.8 parts of zinc acetate was charged, and the mixture was gradually heated to 21
After raising the temperature to 0C, 1.500 parts of terephthalene and 2 parts of diptyltin oxide were added, the temperature was raised to 240C over 10 hours, and the reaction was continued at the same temperature until the acid value was 15. Hydroxyl value is 15, softening point is 117
Polyester resin with G and M'n of 3,700 (
A)' was obtained. Hereinafter, this resin will be abbreviated as (A-2).

Reference example 3 (same as above) 590 m of ethylene glycol (1), 992 parts of 4-obentyl glycol, 1.84 parts of dimethyl terephthalate
7 parts of zinc acetate and 1.9 parts of zinc acetate were charged, the temperature was gradually raised to 210C while removing the methanol produced from the system, and then 41 parts of trimethylolgloban and 1,455 parts of zinc acetate were charged.
After adding MB of inphthalic acid and 2 parts of dibutyltin oxide, the temperature was raised to 240C over 10 hours.

After that, the temperature of the obtained reaction product was lowered to 180C, and 205 parts of trimellitic anhydride was added, and the reaction was continued at the same temperature, resulting in an acid value of 34, a hydroxyl value of 24, and a softening point of 105C. A polyester resin (A) in which 6 was 2,800 was obtained. Hereinafter, this will be abbreviated as resin (A-1).

Reference Example 4 [Preparation example of (β-methyl)glycidyl group-containing polymer CB)] 40 parts of GMA, 5 parts of methyl methacrylate, n
- A mixture of 10 parts of butyl methacrylate, 1 part of tert-butyl perbenzoate and 0.5 parts of cumene hydroveroxide is polymerized under pressure over 100 parts of M noxylene heated to 150°C. After xylene was removed, the desired polymer having a hardness of 1.500 was obtained. Hereinafter, this will be abbreviated as yf polymer CB-1).

Reference Example 5 (Same as above) A mixture of 4 parts of GMA, 20 parts of MGMA, 60 parts of methyl methacrylate, 10 parts of cellosolve methacrylate and 2 parts of t-butyl perbenzoate was heated to 155C under pressure. After adding 100 parts of xylene to 100 parts of xylene and removing the xylene,
The desired polymer having a particle size of 1,300 was obtained. Hereinafter, this will be abbreviated as polymer (B-2).

Examples 1 to 3 Each component shown in Table 1 was triblended, then kneaded in an extruder, cooled, and pulverized to obtain each powder coating.

Thereafter, this powder coating was applied to a zinc phosphate treated steel plate, and then baked at 180C for 20 minutes to obtain each cured coating.

When various performances of the respective coating films thus obtained were investigated, the results shown in the same table were obtained, and it was found that the compositions of the present invention all had coating films with excellent appearance, mechanical strength, weather resistance, etc. It turned out that it can give.

Reference Example 6 (Preparation example of polyester resin for comparison) 562 parts of ethylene glycol, 945 parts of neopentyl f recall, 1.759 parts of dimethyl terephthalate
A mixture of 1.526 parts of terephthalic acid and 18 parts of zinc acetate was gradually heated externally to 210C while removing the methanol produced from the system, and then 1.526 parts of terephthalic acid and 1.526 parts of zinc acetate were added to the mixture.
15 parts of itaconic acid and 2 parts of dibutyltin oxide were added, the temperature was raised to 240C over 10 hours, and the reaction was continued at the same temperature until the acid value was 26, the hydroxyl value was 3, and the softening point was reached. A target polyester resin having a hardness of 116C and a hardness of 3,900 was obtained.

Hereinafter, this will be abbreviated as resin (A'-1).

Comparative Example 1 Absent any use of blocked isocyanate and
A control powder coating was prepared in the same manner as in Examples 1 to 3, except that the composition ratio was changed as shown in the table, and then a cured coating was obtained. When various performances were investigated, the results shown in the table were obtained.

Procedural amendment November 1980 Mr. Manabu Shiga, Director General of the Patent Office■, Minor case indication 1982 Patent Application No. 226799 2, Name of invention 1 for powder coating composition 3, Consideration for amendment Relationship to the incident Patent applicant 35-58 Sakashita, Itabashi-ku, Tokyo 174 (28
B) Dainippon Ink & Chemicals Co., Ltd. Representative: Shigeru Kuni Mura 4, Agent Address: 3-7-20 Nihonbashi, Chuo-ku, Tokyo 103, Dainippon Ink & Chemicals Co., Ltd. Voluntary 6, ? Contents of the amendment in column 7 of "Detailed Description of the Invention" of the subject specification of 1tjF (11) The statement "315 parts of ichconic acid" on page 16, lines 13 to 14 of the specification was changed to "315 parts of ichconic acid". Correct to isophthalic acid 1.

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Claims (1)

[Claims] As an essential component (A): an acid value of 5 to 100 QKOH/J7, a hydroxyl value of 5 to 100 mgKOH/M, and a softening point of 80 to 150;
c, and the number average molecular weight is i, o o o ~ 10,0
00 polyester resin, (B) glycidyl acrylate, glycidyl methacrylate, β-methylglycidyl acrylate and β-
The number average molecular weight obtained from 20 to 100 weight of one or more compounds selected from the group consisting of methyl glycidyl methacrylate and 00 to 80j [i%] of other vinyl monomers is 600 to s, ooo. A polymer containing a glycidyl group and/or β-methylglycidyl group is
40 parts by weight, and (C) a blocked isocyanate in a proportion of 1 to 20 parts by weight.