JPS6058265B2 - High solids coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to thermoplastic high solids coating compositions.

In recent years, air pollution caused by paint solvents has become a problem, and when conventional coating compositions are used, large amounts of solvent are released into the air.Therefore, various efforts have been made to develop paints that use less solvent, and significant progress has been made. .

There are various types of such low air pollution type paints, such as water-soluble, water-dispersed, powder, electron beam, and high solid content paints, but among these, those with a low solvent content and those that require conventional coating equipment and curing High solid content paints are attracting attention because of the availability of equipment and synthesis technology. Thermosetting paints consisting of saturated polyester and crosslinking components such as amino resins have been used for some time, but the solid content concentration for spray painting is 40-5% by volume (hereinafter expressed in %). Even in the case of roll coating, it is 50 to 60%.

It is conceivable to lower the molecular weight of the saturated polyester in order to increase the solids content of such paints, but in that case the paint film would have significant problems in processability, chemical resistance, corrosion resistance, moisture resistance, etc. There is a drawback that it decreases. As a result of studies, the present inventors have discovered a coating composition with a high solid content that can form a coating film with excellent performance.

The term "high solids content" as used herein means that the content of solids, which is a film-forming component, is at least 60%. The present invention refers to a number average molecular weight (hereinafter simply abbreviated as molecular weight).

) is 900 to 3000, unsaturated bond-containing polyester (2) 20 to 8% mass, unsaturated bond-containing oligomer (B) containing two or more unsaturated bonds in one molecule and having a molecular weight of 200 to 700 A high solid content coating composition comprising 10 to 4% by weight of a crosslinking component (C) such as an aminoplast resin, an epoxy resin, or an isocyanate compound as a film-forming component. This composition has the following features. (1)
Paints with a high solids content of 70% or more can also be produced. (2) The coating film obtained by heat curing has excellent adhesion to the metal substrate. (3) The surface hardness is extremely high and there is no need to worry about blocking. (4) A highly elastic coating film with excellent workability can be obtained. The above-mentioned unsaturated bond-containing polyester (4) used in the present invention is a polyester having a large number of unsaturated bonds in the main polymer, in the side chain, or at the end.

Its molecular weight is 900-3000, preferably 10
00-2000. If the molecular weight is less than 90, the molecular weight between crosslinks is too small and sufficient processability cannot be imparted to the cured coating, and if it exceeds 3000, it is difficult to obtain a high solid content coating, which is the objective of the present invention. It's inappropriate. The unsaturated bond-containing polyester has a hydroxyl group and/or a carboxyl group for a crosslinking reaction with a crosslinking component used in combination. Usually, a hydroxyl value of 20 to 200K0Hm9/y (hereinafter units are abbreviated) and an acid value of 20 to 200 are appropriate. The above polyester can be produced by reacting an acid component containing an unsaturated bond-containing component with an alcohol component by a well-known method. In addition, a vinyl monomer having a functional group that is mutually reactive with these functional groups is added to the carboxyl group or hydroxyl group contained in an unsaturated bond-containing or unsaturated bond-free polyester prepared by a well-known method to form a polyester skeleton. An unsaturated bond-containing polyester (4) resin can also be produced by a method of introducing an unsaturated bond into. The vinyl monomer may be added by dissolving the polyester in a solvent and heating the solution. Examples of carboxylic acid components that are raw materials for producing the unsaturated bond-containing polyester (4) include malonic acid, succinic acid, maleic acid (anhydride), itacic acid, adipic acid, phthalic acid (anhydride), isophthalic acid, and tetrabromophthalic acid. Acid, linear or branched with 2-2 carbon atoms such as tetrahydrophthalic acid, dimethyl terephthalic acid, naphthalene dicarboxylic acid, citraconic acid, diglycolic acid, trimellitic acid (anhydride), pyromellitic acid (anhydride), etc. In addition to aliphatic, aromatic or alicyclic polycarboxylic acids and aralkyl polycarboxylic acids, soybean oil fatty acids, linseed oil fatty acids, coconut oil fatty acids, benzoic acid, paratertiary butylbenzoic acid, abietic acid, etc. Aliphatic, aromatic, and alicyclic monocarboxylic acids such as the following can be used.

Examples of alcohol components include ethylene glycol, propylene glycol, neopentyl glycol, bisphenol A1 hydrogenated bisphenol All, 6-hexanediol, and polyalkylene glycols having 1-1-ether bonds in the molecule (e.g. diethylene glycol, dipropylene In addition to diols such as glycol, polyethylene glycol, polypropylene glycol, polytetrahydrofuran, polyethylene oxide, polypropylene oxide), glycerin, trimethylolpropane, 1,3,6-hexanetriol, trimethylolethane, pentaerythritol, sorbitol, Trifunctional or higher functional polyols such as glycose can also be used. Among vinyl monomers for introducing unsaturated bonds, those having carboxyl group reactivity include (meth)acrylic acid glycidyl ester, (meth)allyl glycidyl ether, and vinyl cyclohexane. α, β of monooxide etc.
There are glycidyl alkyl esters of monoethylenically unsaturated carboxylic acids and glycidyl ethers of vinyl monomers containing hydroxyl groups, and examples of hydroxyl-reactive ones include anhydrides such as maleic acid, itaconic acid, and tetrahydrophthalic acid. be. The unsaturated bond-containing oligomer (B) used in the present invention is an oligomer having two or more unsaturated bonds in one molecule, and has a molecular weight of 200 to 700.

If the molecular weight is less than 20, evaporation and scattering during baking hardening will be severe, and smoke generation will be severe, especially under conditions of short-time baking at a high temperature of 200° C. or higher. Also, the molecular weight is 70
If it exceeds 0, it will be difficult to obtain a composition with a high solid content due to poor fluidity, and it will also be difficult to obtain a sufficient crosslinking density, which will have an adverse effect on chemical resistance and the like. The unsaturated bond-containing oligomer (B) used in the present invention includes the following. (1) A low molecular weight condensate of (meth)acrylic acid and a polyhydric alcohol and/or an acid group-containing vinyl monomer (e.g. hydroxyalkyl methacrylate, allyl alcohol), (2) a polyhydric carboxylic acid and a hydroxyl group-containing vinyl monomer. (3) low molecular weight adducts with hydroxyl group-containing vinyl monomers, acid anhydrides, epoxy group-containing vinyl monomers (e.g. glycidyl acrylate, allyl glycidyl ether, vinyl cyclohexane monoxide, etc.), (4) polyhydric (5) low molecular weight adducts of polyhydric alcohols, acid anhydrides, and glycidyl group-containing vinyl monomers; (6) active hydrogen-containing vinyl monomers (e.g., hydroxyl group-containing vinyl monomers); (other monomers itaconic acid, N-methylolacrylamide, crotonic acid) and polyisocyanates (e.g. toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, adducts of these isocyanates and polyhydric alcohols) (7) A low molecular weight adduct that is a reaction product of a low molecular weight polyepoxide and a carboxyl group-containing vinyl monomer. Furthermore, the crosslinking component (C) used in the present invention is a component that reacts with the carboxyl group or hydroxyl group contained in the unsaturated bond-containing polyester (4) to bring about a crosslinking effect, and usually Most commonly used thermosetting resins can be used, but the most representative ones include aminoblast resin, epoxy resin, and isocyanate compounds. For example, there are etherified products in which a condensate of an amino compound such as melamine, urea, or acetoguanamine and formaldehyde is etherified with a monohydric alcohol having 1 to 5 carbon atoms.
1 (hexamethoxymethyl etherified melamine manufactured by American Cyanamid), Super Beckamine J-820
-60, G-821-60 (butyl-isobutyl etherified melamine resin manufactured by Dainippon Ink Chemical), and the like.

Epoxy resins can also be used, such as Epicote 828, 1001, and 1004 (bisphenol A◆epichlorohydrin type epoxy resin manufactured by Shell Chemical), glycerin glycidyl ether, neopentyl glycol glycidyl ether, trimethylolpropane triglycidyl ether, and the like. Isocyanate-terminated compounds can also be used, such as diisocyanates such as toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, etc., and these diisocyanates and polyhydric alcohols reacted in an excess amount of isocyanate groups. products (for example, Desmodille L manufactured by Bayer)
Trimethylolpropane adducts of tolylene diisocyanate such as Takenate D-110-N manufactured by Takeda Pharmaceutical Co., Ltd., trimethylolpropane adducts of xylene diisocyanate such as Takenate D-110-N manufactured by Takeda Pharmaceutical Co., Ltd.), polymerized polyisocyanates such as Desmodyuru N manufactured by Bayer AG There are products of 3 moles of hexamethylene diisocyanate and 1 mole of water, and there are also products in which the various isocyanate compounds or their derivatives are blocked with a known and commonly used blocking agent. As mentioned above, the composition of the present invention has a molecular weight of 900 to
3000 unsaturated bond-containing polyester CA) 20-8
0%, oligomer (B) with a molecular weight of 200 to 700 and having unsaturated bonds (B) 10 to 40%, and crosslinking component (C) 10 to 40%
more preferably 40 to 6 each.
The ranges are 0%, 20-30% and 20-30%.

The crosslinking and curing mechanism of the above composition is a copolymerization reaction of the unsaturated bonds contained in the unsaturated bond-containing polyester (4) and the unsaturated bond-containing oligomer (B), respectively. ) and the mutually reactive functional groups contained in the crosslinking component (C). The former crosslinking reaction is carried out by baking in the presence or absence of a radical generating catalyst or metal salt drying agent, and the latter crosslinking reaction is carried out by baking in the presence or absence of a reaction accelerator. Ru. Examples of radical generating catalysts that can be used include the following.

Inorganic oxides such as hydrogen peroxide and persulfates, 2.2″-
azo and azo compounds such as azobisnitriles such as azobisisobutyronitrile and 2,2″-azobisprobionitrile, diazoaminobenzenes, nitrosoamylallylamines, azothioethers, and p-nitrobenzene azonium salts; Benzoyl peroxide, nuclear substituted benzoyl peroxide (P, p″-dimethoxy, p-monomethoxy, M, m″-dimethoxy, m-monomethoxy, P, p-
Di-t-butyl, P,p''-dimethyl, M,m''-dimethyl, p-methyl-m''-bromo, P,p''-dichloro, M,m''-dichloro, P,p-dibromo, M,m-dibromo, P, p″-dicyano, M, ml-dicyano,
m-monocyano, M, m″-dinitro, P, p-dinitro), lauroyl peroxide, acetyl peroxide, ketonone peroxide, kyumene hydroperoxide, t-butyl human peroxide, di-t-butyl peroxide, etc. organic peroxides, sulfinic acids such as aromatic sulfinic acids, 1-alkali sulfinic acids, etc. Combinations of initiators and accelerators as described below can also be used: benzoyl peroxide as a radical initiator; When used, N,N-dialkylaniline, N,N
-dimethoxytoluidine, N,N-dimethyl-p-anisidine, 2●5-dimethoxyN,N-dimethylaniline, p-halogen-N,N-dialkylaniline, 2-
N-methylanilinoethanol, 2-N-ethylanilinoethanol, 2●2″-(phenylimino)diethanol, 2●2″-(m-tolylimino)diethanol,
Accelerators such as tetrahydroquinoline, tri-n-butylamine, triethanolamine, diazothioether, p-toluenesulfonic acid are used. In addition, when kyumene hydroperoxy is used as an initiator, a monoamine or polyamine is used as an accelerator, and when potassium persulfate or ammonium persulfate is used as an initiator, complex salts of cobalt (or chromium, nickel, iron, manganese), hydrazine, etc. , hydroxylamine, sodium sulfite, triethanolamine, etc. can be used. Examples of the metal salt desiccant include the following.
Cobalt naphthenate, lead naphthenate, manganese naphthenate, calcium naphthenate, zinc naphthenate, iron naphthenate, zirconium naphthenate, cerium naphthenate,
Naphthenates of various metals such as copper naphthenate, octoates of these metals, metal salt desiccants such as linseed oil, fatty acid salts, soybean oil fatty acid salts, and tall oil fatty acid salts. Examples of reaction accelerators include amines such as 2-methylimidazole and trimethylamine, paratoluene. Acids such as sulfonic acid and hydrochloric acid, alkali metal compounds, and tin compounds can be used. The composition of the present invention has an unprecedentedly high solids content, but when using it, pigments and other well-known ingredients can of course be added to the coating. Needless to say, spraying or other well-known painting methods may be used.

Next, the present invention will be specifically explained using reference examples, working examples, and comparative examples.

In the following, unless otherwise specified, all "parts" refer to parts by weight. Reference Example 1 [Unsaturated bond-containing polyester (4)
Preparation example] 10(1) parts of neopentyl glycol, 2 parts of trimethylolpropane, 3(1) parts of adipic acid
1 part, 9W parts of phthalic anhydride, and 1a part of maleic anhydride were charged into a 4-hole flask and reacted at 200°C for 8 hours to obtain an acid value of 20.
, an unsaturated bond-containing polyester with a molecular weight of about 1100 (4
) was obtained.

This was dissolved in xylene so that the solid content was 70%. The viscosity of this resin solution is I-J (Gardner-Hold method,
The same applies hereafter). Reference Example 2 (same as above) 355 parts of ethylene glycol, 996 parts of neopentyl glycol, 4 parts of propylene glycol, 100 parts of adi-L-pic acid, 490 parts of maleic anhydride, 16 parts of isophthalic acid.
35 parts were reacted at 200℃ for 15A to give an acid value of 40 and 0H.
An unsaturated bond-containing polyester (4) having a valence of 101 and a molecular weight of about 2,000 was obtained.

The viscosity of a xylene solution of this resin with a solid content of 60% was T. Reference Example 3 (same as above) To 200 parts of the resin solution of Reference Example 2, add the mound of glycidyl methacrylate, 0.5 part of triethylamine, and 0.1 part of hydroquinone, and react at 110°C for 5 hours to adjust the acid value. is 3, the viscosity is V, and the solid content is 60%
A xylol solution was obtained.

Example 1 500 parts of the resin solution of Reference Example 1, 28 parts of trimethylolpropane trimethacrylate, 1 part of hexamethoxymelamine, 70 parts of titanium oxide (2), 1 part of xylol (1 part)
) parts in a ball mill, and then add 200 parts of xylene,
One part of diterciabutyl peroxide was added and applied to a metal plate using a sprayer, followed by powder firing at 150°C three times.

Example 2 500 parts of the polyester solution of Reference Example 2, 2 (1) parts of polyester oligomer, 100 parts of Epikote 828100ml hexamethoxymelamine, 70Df titanium oxide! 1
1) After kneading Xylol 10 in a ball mill, 1 part of Kyumene hydroperoxide was added.

The obtained composition was heated to 50° C., sprayed onto a metal plate, and powder-baked at 160° C. 3 times. The polyester oligomer is an ester compound of 1 mole of 2,2-dimethyl-3-hydroxypropyl, 2,2-dimethyl-3-hydroxypropionate and 2 moles of acrylic acid.

Example 3 After kneading 500 parts of the polyester solution of Reference Example 3, 200 parts of trimethylolpropane methacrylate, and 57 parts of titanium oxide in a ball mill, 1 part of ditertiary butyl peroxide, 1 part of desmodyl N7O, and 2 (1) parts of xylol were added. Further, this composition was applied to a metal plate by spraying and baked in a 150×2 powder.

Example 4 After kneading 500 parts of the polyester solution of Reference Example 1, 210 parts of trimethylolpropane trimethacrylate, 14 parts of hexamethoxymelamine, 7 (4) parts of titanium oxide, and 100 parts of xylol in a ball mill, 1 part of ditertiary butyl peroxide was mixed. The mixture was coated on a metal plate using a percoater and baked at 260°C for 1 minute.

Example 5 300 parts of the polyester solid of Reference Example 2, 2 parts of polyethylene glycol dimethacrylate with a degree of polymerization of 9,
Hexamethoxymethyl melamine 18%, titanium oxide 72%
After heating 0 part to 50°C and kneading in a ball mill, 1 part of kyumene hydroperoxide was added.

The obtained coating composition was applied to a metal plate using a roll coater heated to 70 to 80°C and baked at 240°C for 1 minute. Example 6 After kneading 500 parts of the polyester solution of Reference Example 3, 15 parts of trimethylolpropane trimethacrylate, 00 parts of 1,6-hexanediol dimethacrylate, and 5 parts of titanium oxide in a ball mill, ditertiary butyl peroxide was prepared. 1 part, Takenate D-110-N Jun part, Xylol 1 part
Add the (to) part and apply it to the metal plate with a percoater for 240 minutes.
Baked at ℃×1 minute.

Example 7 500 parts of the polyester solution of Reference Example 2, 250 parts of an 8% cellosolve acetate solution of an adduct obtained by adding 2 moles of β-hydroxyethyl methacrylate to 1 mole of hexamethylene diisocyanate, and 5 parts of titanium oxide were kneaded in a ball mill. After that, 1 part of ditertiary butyl peroxide, 1 part of Desmodyuru N(A), 2 parts of xylol (
Added the Capital) Department.

The obtained composition was applied to a metal plate by spraying at 150×
I burned 2 pieces. Example 8 500 parts of the polyester solution of Reference Example 3, Epikote 82
80% solution of xylene, an adduct of 2 moles of methacrylic acid added to 81 moles, 25% solution of xylene, 570ffI of titanium oxide)
After kneading in a ball mill, 1 part of ditertiary butyl peroxide, Takenate D-110-N7 and 2 (1) parts of xylene were added.

The obtained composition was applied to a metal plate by spraying at 150×
I burned 2 pieces. Example 6 500 parts of the polyester solution of Reference Example 2, 80% cellosolve solution 25 in which 2 moles of β-hydroxyethyl methacrylate was added to 1 mole of hexamethylene diisocyanate.
titanium oxide 570W), Epicoat 8282 part,
After kneading 1 (1) part of xylol in a ball mill, 1 part of ditarsia butyl peroxide, and Desmodyuru N8
Part O and Xylol 7 were added.

The obtained composition was applied to a metal plate by spraying at 150×
I burned 2 pieces. Example 10 500 parts of the polyester solution of Reference Example 1, 310 parts of a 90% xylene solution of an adduct obtained by adding 2 moles of glycidyl methacrylate to 1 mole of maleic acid, part D of hexamethoxymelamine, 70 W of titanium oxide), and 100 parts of xylene were ball milled. After kneading, 1 part of ditertiary butyl peroxide was added.

The obtained composition was applied to a metal plate using a roll coater heated to 70 to 80°C and baked at 240° C. for 1 minute. Example 1
1 500 parts of the polyester solution of Reference Example 1, 1 mole of β-hydroxyethyl methacrylate, 1 mole of phthalic anhydride, and 1 mole of glycidyl methacrylate adduct xylol 9
After kneading 2 (9) parts of 0% solution, 14 parts of hexamethoxymelamine, 700 ml of titanium oxide, and 6 parts of xylol in a ball mill, 1 part of ditertiary butyl peroxide was added.
It was applied to a metal plate using a percoater and baked at 260°C for 1 minute.

Example 12 500 parts of the unsaturated bond-containing polyester solution obtained in Reference Example 3, 150 ml of trimethylolpropane trimethacrylate, 100 ml of 11,6 hexanediol dimethacrylate, and 550 parts of titanium oxide were kneaded in a ball mill, and further mixed with ditarsia. Ributyl peroxide 1
part, 7 parts of "Takenate D-1101N", 3 parts of hexamethoxymethylmelamine and 130 m of xylol
Thereafter, the resulting coating composition was applied to a metal plate using a percoater and baked at 240° C. for 1 minute.

Example 13 50 parts of the polyester solution of Reference Example 2, 1 part of trimethylolpropane trimethacrylate, 10 parts of 1.6 hexanediol dimethacrylate, and 550 parts of titanium oxide were kneaded in a ball mill, and further mixed with ditercia. Part of Ributyl Peroxide, "Epicote 828"
100 parts of and 13 parts of xylol? Thereafter, the coating composition thus obtained was applied to a metal plate using a percoater and baked at 240° C. for 1 minute.

Example 14 5 (a) parts of the polyester solution of Reference Example 3,
15% of trimethylolpropane trimethacrylate,
100 parts of 1,6 hexanediol methacrylate and 550 parts of titanium oxide were kneaded in a ball mill, and further mixed with 1 part of ditertiary butyl peroxide, the marking part of "Copicoat 828", and m of hexamethoxymethyl melamine.
6(2) of "Takenate D-110-N" and 130 parts of xylol were added, and then the resulting coating composition was applied to a metal plate with a percoater to form a 240×1
It was baked for 1 minute.

Example 15 5 (1) parts of the polyester solution of Reference Example 2, 150 parts of trimethylolpropane trimethacrylate, 100 parts of 1,6 hexanediol dimethacrylate, and 550 parts of titanium oxide were kneaded in a ball mill, and further mixed with a diteriyar. Part of butyl peroxide, "Epicote 828"
'', part a of ``Takenate D-110-N'' and 13 portions of xylol were added, and the resulting coating composition was applied to a metal plate using a percoater and heated at 240°C.
Baking was performed for 1 minute.

Example 16 5 (4) parts of the polyester solution of Reference Example 2, 15 parts of trimethylolpropane trimethacrylate, 100 parts of 1,6 hexanediol dimethacrylate, and 550 parts of titanium oxide were kneaded in a ball mill, and further 1 part of diterciabutyl peroxide, 1 (1) part of hexamethoxymethyl melamine, "Takenate D-110-
Methyl ethyl ketoxime ●blocked product (support) of N”
1 part of dibutyltin dilaurate and 130 parts of xylene were then applied to a metal plate using a percoater and baked at 240'C for 1 minute.

Comparative Example 1 Kneading, blending, painting and baking were carried out in the same manner as in Example 1, except that no hexamethoxymethylmelamine was used.

Comparative Example 2 Hexamethoxymethylmelamine and “Epicote 82
Kneading, blending, painting, and baking were carried out in the same manner as in Example 2, except that "No. 8" was not used at all.

Comparative Example 3 Kneading, blending, painting and baking were carried out in the same manner as in Example 6, except that "Takenate D-110-N" was not used at all.

Comparative Example 4 Comparative Example 2 was carried out in the same manner as in Comparative Example 2, except that the baking conditions were changed to 240° C. for 1 minute.

Comparative Example 5 The same procedure as Comparative Example 3 was carried out except that the baking conditions were changed to 150°C x 3 powders.

Table 1 (medium temperature baking: 150-160°C x 20-3 powder example) or A summary is shown in Table 2 (example of high temperature baking: 240 to 260°C x 1 minute).

Claims (1)

[Claims] 1 (A) 20 to 80% by weight of an unsaturated bond-containing polyester with a number average molecular weight of 900 to 3,000, (B) a number average molecular weight of 20 to 20, with two or more unsaturated bonds in one molecule.
0 to 700 unsaturated bond-containing oligomer, and (C) 10 to 40 weight % of a crosslinking component such as an aminoplast resin, an epoxy resin, or an isocyanate compound as a film forming component. Composition.