JP3099078B2 - Thermosetting resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermosetting resin composition comprising an organic polyol, an alkoxysilyl group-containing acrylic copolymer and an amino resin as essential components. The thermosetting resin composition is useful as a paint for home appliances, a paint for exteriors such as buildings or PCM, a paint for a top coat for automobiles, a coating agent for glass or ceramic products, a sealing agent, an adhesive and the like.

[0002]

BACKGROUND OF THE INVENTION As thermosetting paints, alkyd melamine, acrylic melamine,
Epoxy melamine resin paints are widely used. Each of these uses a melamine resin and is widely used as a thermosetting paint because of its one-pack type and low cost.

[0003] However, these conventional melamine resin paints have the problem that the coating film is etched, whitened, stained, etc., due to acid rain caused by air pollution in recent years. In addition, there is also a problem that a scratch is generated by a brush, a cloth or the like when the car is washed. Therefore, there is an extremely high need for a coating film having good weather resistance, acid resistance, and scratch resistance.

The present inventors have previously filed an application (JP-A-56-32539) for a thermosetting composition comprising an alkoxysilyl group-containing compound and an amino resin. It discloses that a cured acrylic paint or a melamine paint can be mixed and used. However, this did not fully satisfy the needs of the above-mentioned coating film.

[0005]

Means for Solving the Problems Accordingly, the present inventors have:
For example, in order to obtain a coating film with good weather resistance, acid resistance, and scratch resistance without impairing the appearance as an automotive top coat, a vinyl copolymer containing an alkoxysilyl group having good weather resistance and As a result of intensive research on the structure and composition of the organic polyol and melamine resin, which are the main components of the melamine paint of the present invention, it was found that a coating film having the above properties can be obtained with a specific structure and composition, and the present invention was completed. It led to. That is, the present invention relates to (A) 69 to 5 parts by weight of an organic polyol having a hydroxyl value of 20 to 350 mgKOH / g, and (B) an alkoxysilyl group-containing acrylic containing 20 to 90% by weight of an alkoxysilyl group-containing vinyl monomer. The present invention provides a thermosetting resin composition comprising 30 to 80 parts by weight of a polymer and (C) 1 to 15 parts by weight of an amino resin as essential components.

The organic polyol (A) used in the present invention (hereinafter also referred to as the organic polyol (A) or simply component (A)) is a hydroxyl group-containing acrylic resin,
It is an organic polyol selected from a hydroxyl group-containing polyester resin and a hydroxyl group-containing fluoroolefin copolymer, and one or a mixture of two or more thereof may be used.

The hydroxyl group-containing acrylic resin includes a copolymer of a hydroxyl group-containing vinyl monomer and another vinyl monomer. Specific examples of the hydroxyl group-containing vinyl monomer include 2-hydroxyethyl (meth) acrylate, 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl vinyl ether, and N
-Methylol (meth) acrylamide, Alonix 5700, 4-hydroxystyrene manufactured by Toa Gosei Chemical Industry Co., Ltd., HE-10, HE manufactured by Nippon Shokubai Chemical Industry Co., Ltd.
20, HP-10 and HP-20 (acrylate oligomers each having a hydroxyl group at a terminal), Blenmer PP series (polypropylene glycol methacrylate), Blenmer PE series (polyethylene glycol monomethacrylate) manufactured by NOF Corporation, Blenmer PEP series (polyethylene glycol polypropylene glycol methacrylate), Blemmer AP
-400 (polypropylene glycol monoacrylate), Blemmer AE-350 (polyethylene glycol monoacrylate), Blemmer NKH-5050
(Polypropylene glycol polytrimethylene monoacrylate), Blemmer GLM (glycerol monomethacrylate), and a hydroxyl-containing vinyl compound and ε-
And ε-caprolactone-modified hydroxyalkyl vinyl monomers obtained by reaction with caprolactone. Above all, by using an ε-caprolactone-modified hydroxyalkylvinyl-based monomer, the impact resistance and flexibility of the coating film can be improved.

[0008] Representative examples of the ε-caprolactone-modified hydroxyalkyl vinyl monomer include, for example, those represented by the formula:

Embedded image (Wherein, R represents H or CH ₃ , and n represents an integer of 1 or more) Placel FA-1 (R = H, n =
1), Placel FA-4 (R = H, n = 4),
Placel FM-1 (R = CH ₃ , n = 1) and Placel FM-4 (R = CH ₃ , n = 4),
And TONE M-100 (R =
H, n = 2) and TONE M-201 (R = C
H ₃ , n = 1).

These vinyl monomers having a hydroxyl group include:
Seeds may be used, or two or more kinds may be used in combination.

Acrylic acid or methacrylic acid derivatives copolymerizable with a hydroxyl group-containing vinyl monomer are not particularly limited, and specific examples thereof include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl ( (Meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) Acrylate, perfluorocyclohexyl (meth) acrylate, (meth) acrylonitrile,
Glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (meth) acrylamide, α-ethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acryloylmorpholine, N-methylol (meth) acrylamide, AS-6, A, a macromonomer manufactured by Toa Gosei Chemical Industry Co., Ltd.
Α, β- such as N-6, AA-6, AB-6, AK-5, and hydroxyalkyl esters of (meth) acrylic acid
Examples thereof include a phosphoric acid ester group-containing vinyl compound as a condensation product of a hydroxyalkyl ester of an ethylenically unsaturated carboxylic acid and phosphoric acid or a phosphoric acid ester, and a (meth) acrylate containing a urethane bond or a siloxane bond.

The component (A) may contain a segment formed by a urethane bond or a siloxane bond in the main chain within a range not exceeding 50% (% by weight, the same applies hereinafter). A segment derived from a monomer other than the acid derivative may be included. The monomer is not limited, and specific examples thereof include, for example, styrene, α-
Aromatic hydrocarbon-based vinyl compounds such as methylstyrene, chlorostyrene, styrenesulfonic acid, and vinyltoluene; unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid, and salts thereof (alkali metal salts, ammonium salts, amines) Salts thereof), their anhydrides (such as maleic anhydride), or esters of unsaturated carboxylic acids such as diesters or half-esters thereof with linear or branched alcohols having 1 to 20 carbon atoms; vinyl acetate,
Vinyl esters and allyl compounds such as vinyl propionate and diallyl phthalate; vinyl compounds containing amino groups such as vinyl pyridine and aminoethyl vinyl ether;
Amino-containing vinyl compounds such as itaconic acid diamide, crotonamide, maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone; methyl vinyl ether;
Other vinyl compounds such as cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, fluoroolefin maleimide, N-vinylimidazole, and vinyl sulfonic acid.

The hydroxyl group-containing acrylic resin as one of the components (A) used a peroxide radical initiator such as t-butyl peroxyacetate and an azo radical initiator such as azobisisobutyronitrile. It is preferably produced by a solution polymerization method. In the polymerization by the solution polymerization method,
If necessary, the molecular weight may be adjusted using a chain transfer agent such as n-dodecyl mercaptan, t-dodecyl mercaptan, or n-butyl mercaptan. The polymerization solvent can be used without particular limitation as long as it is a non-reactive solvent.

The hydroxyl group-containing acrylic resin as described above,
Further, a non-aqueous dispersion type in which particles of the hydroxyl group-containing acrylic resin are dispersed in an organic solvent that does not dissolve the acrylic resin, for example, pentane, hexane, heptane or the like may be used.

The hydroxyl group-containing acrylic resin has a number average molecular weight of 1,500 to 40,000, preferably 2,000 to 40,000.
25,000 and a glass transition temperature of -50 to 50.
° C, preferably -20 to 20 ° C.

The hydroxyl group-containing polyester resin which can be the organic polyol (A) in the present invention includes any of oil-free polyester polyol, alkyd polyol, polycaprolactone polyol, polyvalerolactone polyol, and polycarbonate polyol. Its anhydride, isophthalic acid,
Polybasic acid components such as terephthalic acid, hexahydrophthalic acid, methyl hexahydrophthalic acid, adipic acid, trimellitic acid and its anhydride, pyromellitic acid and its anhydride, and ethylene glycol, propylene glycol, diethylene glycol, Neopentyl glycol,
1,6-hexanediol, trimethylolpropane,
Glycerin, pentaerythritol, those obtained by polycondensation with a polyol component such as tricyclodecane dimethanol according to a conventional method, ε-caprolactone, γ-valerolactone diol, triol, and those obtained by ring-opening polymerization using tetraol as an initiator, Examples thereof include aliphatic carbonate diols, and those having a number average molecular weight in the range of 500 to 5,000 are used.

The hydroxyl group-containing fluoroolefin copolymer which can be an organic polyol (A) in the present invention is a copolymer of vinyl monomers such as trifluoroethylene, hydroxyalkyl vinyl ether, alkyl vinyl ether and vinyl acetate. In general,
Lumiflon (made by Asahi Glass Co., Ltd.) LF-100, LF-
200, LF-300, LF-400 and the like.
The use of the fluoroolefin copolymer can impart water repellency to the coating film.

The hydroxyl group-containing acrylic resin, hydroxyl group-containing polyester resin and hydroxyl group-containing fluoroolefin copolymer, which are the organic polyols (A) of the present invention, must all have a hydroxyl group serving as a crosslinking point. The hydroxyl value of these resins is 20 to 350 mg KOH / g,
Preferably it is 30-250 mgKOH / g, more preferably 50-200 mgKOH / g. Hydroxyl value is 20
If the amount is less than mgKOH / g, the crosslink density required to maintain the solvent resistance of the cured coating film cannot be obtained.
/ G, the crosslink density becomes too high, causing problems such as cracking of the coating film due to curing shrinkage.

The organic polyol (A) of the present invention includes:
The hydroxyl group-containing acrylic resin, the hydroxyl group-containing polyester resin, may be any of the hydroxyl group-containing fluoroolefin copolymer, but a hydroxyl group-containing acrylic resin is preferred from the viewpoint of weather resistance, and among the hydroxyl group-containing polyester resin, a polycarbonate polyol is used. It is preferable from the viewpoint of acid resistance.

The alkoxysilyl group-containing acrylic copolymer (B) used in the present invention (hereinafter referred to as alkoxysilyl group-containing acrylic copolymer (B), or simply
Also referred to as component (B). ) Has the general formula:

Embedded image Is a polymer having at least one, and preferably two or more, alkoxysilyl groups represented by the following formula: This alkoxysilyl group may be contained at the terminal of the main chain of the component (B), may be contained in a side chain, or may be contained in both. When the number of alkoxysilyl groups in one molecule of the component (B) is less than 1, the solvent resistance of the coating film obtained from the composition of the present invention tends to decrease.

In the above general formula, R ¹ is an alkyl group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms. When the number of carbon atoms exceeds 10, the reactivity of the alkoxysilyl group decreases, and the reactivity also decreases when R ¹ is other than an alkyl group, for example, a phenyl group or a benzyl group. Specific examples of R ¹ include, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and the like.

In the above formula, R ² is a hydrogen atom or 1 selected from the group consisting of an alkyl group having 1 to 10 (preferably 1 to 4) carbon atoms, an aryl group and an aralkyl group.
Is a monovalent hydrocarbon group. Specific examples of the alkyl group as R ² include the same groups as those of R ¹ , specific examples of the aryl group include a phenyl group, and specific examples of the aralkyl group include a benzyl group and the like. Is raised.

In the above general formula, a is 0, 1 or 2
Is shown.

Specific examples of the alkoxysilyl group represented by the above general formula include, for example, groups contained in an alkoxysilyl group-containing vinyl monomer described below.

The alkoxysilyl group-containing acrylic copolymer (B) is excellent in weather resistance, chemical resistance, water resistance and the like of the cured product since its main chain is substantially composed of an acrylic copolymer chain. Further, since the alkoxysilyl group is bonded to the carbon atom, the cured product is excellent in water resistance, alkali resistance, acid resistance and the like.

The number average molecular weight of the alkoxysilyl group-containing acrylic copolymer (B) is from 1,000 to 30, from the viewpoint of physical properties such as durability of a coating film obtained from the composition of the present invention.
2,000 is preferable, and 2,000 to 25,000 is more preferable.

The component (B) can be obtained, for example, by copolymerizing acrylic acid, methacrylic acid, a derivative thereof and the like with an alkoxysilyl group-containing vinyl monomer.

Such acrylic acid or methacrylic acid derivatives are not limited, and specific examples thereof include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate and isobutyl (meth) acrylate. ) Acrylate, 2-ethylhexyl (meth)
Acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, (meth) acrylonitrile, glycidyl (Meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (meth) acrylamide, α-ethyl (meth) acrylamide, N-
Butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acryloylmorpholine, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, N-methylol (meth) acrylamide, Toa Gosei Aronix M-5700 manufactured by Chemical Industry Co., Ltd., AS-6, a macromonomer manufactured by Toa Gosei Chemical Industry Co., Ltd.,
AN-6, AA-6, AB-6, AK-5, Placel FA-1, Plac manufactured by Daicel Chemical Industries, Ltd.
cel FA-4, Placel FM-1, Pla
ccel FM-4, a phosphate ester group which is a condensation product of a hydroxyalkyl ester of an α, β-ethylenically unsaturated carboxylic acid such as a hydroxyalkyl ester of (meth) acrylic acid and a phosphoric acid or a phosphoric acid ester Vinyl compounds, (meth) acrylates containing urethane bonds or siloxane bonds, and the like.

The alkoxysilyl group-containing vinyl monomer is not particularly limited except that it has a polymerizable double bond, and specific examples thereof include, for example,

Embedded image

Embedded image And a (meth) acrylate having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond.

The proportion of the alkoxysilyl group-containing vinyl monomer in the component (B) is preferably from 20 to 90% by weight from the viewpoint of the curability of the composition and the weather resistance of the coating film, and is preferably from 20 to 70% by weight.
0% by weight is more preferred.

The component (B) may contain a segment formed by a urethane bond or a siloxane bond in the main chain within a range not exceeding 50%, and a monomer other than the (meth) acrylic acid derivative may be used. May be included. This monomer is not limited, and specific examples thereof include, for example, styrene, α-methylstyrene,
Aromatic hydrocarbon-based vinyl compounds such as chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, and vinyltoluene; unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid, and salts thereof (alkali metal salts, ammonium salts) , Amine salts and the like), their anhydrides (such as maleic anhydride), or esters of unsaturated carboxylic acids such as diesters or half-esters thereof with linear or branched alcohols having 1 to 20 carbon atoms; acetic acid Vinyl esters and allyl compounds such as vinyl, vinyl propionate and diallyl phthalate; vinyl compounds containing an amino group such as vinylpyridine and aminoethyl vinyl ether; itaconic diamide, crotonamide, maleic diamide, fumaric diamide, and N-vinylpyrrolidone Including amide group Vinyl compounds; 2-hydroxyethyl vinyl ether, methyl vinyl ether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride,
Chloroprene, propylene, butadiene, isoprene,
Other vinyl compounds such as fluoroolefin maleimide, N-vinylimidazole, and vinyl sulfonic acid are included.

The alkoxysilyl group-containing acrylic copolymer (B) can be produced, for example, by the methods described in JP-A-54-36395, JP-A-57-36109, and JP-A-58-157810. Although it can be produced, it is most preferable to produce it by a solution polymerization method using an azo radical initiator such as azobisisobutyronitrile from the viewpoint of ease of synthesis.

In this case, if necessary, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane ,
The molecular weight can be adjusted using a chain transfer agent such as γ-mercaptopropylmethyldiethoxysilane, (CH ₃ O) ₃ Si—S—S—Si (OCH ₃ ) ₃ . In particular, it is preferable to use a chain transfer agent having an alkoxysilyl group in the molecule, for example, γ-mercaptopropyltrimethoxysilane, because the alkoxysilyl group can be introduced to the terminal of the silyl group-containing acrylic copolymer.

The polymerization solvent used in the solution polymerization method includes hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetates (ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, etc.). , Isopropanol, n-butanol, etc.),
The solvent is not particularly limited as long as it is a non-reactive solvent such as ethers (ethyl cellosolve, butyl cellosolve, cellosolve acetate, etc.) and ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, acetone, etc.).

As the alkoxysilyl group-containing acrylic copolymer (B), one kind may be used alone, or two or more kinds may be used in combination.

Scratch resistance, which is a characteristic of a coating film obtained from the composition of the present invention, is also affected by the comonomer composition of the alkoxysilyl group-containing acrylic copolymer (B) in the composition. :

Embedded image Can be improved by using a (meth) acrylate represented by the formula (1) as a copolymerization monomer.

Specific examples of the (meth) acrylate include isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate,
Isodecyl (meth) acrylate, secondary butyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 3,3
5-trimethylcyclohexyl (meth) acrylate,
Isopentyl (meth) acrylate, 2,2-dimethylpropyl (meth) acrylate, isooctyl (meth)
Acrylate and the like, and the copolymerization amount thereof is 5 to 70 in the alkoxysilyl group-containing acrylic copolymer (B).
% By weight, more preferably in the range of 10 to 50% by weight.

The amino resin of component (C) used in the present invention (hereinafter also referred to as amino resin (C) or simply component (C)) includes melamine, urea, benzoguanamine, glycol urea, and acetoguanamine. And a methylolated amino resin obtained by reacting an amino component such as dicyandiamide with an aldehyde. Aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Further, the methylolated amino resin is prepared by adding methyl alcohol, ethyl alcohol, n-propyl alcohol, i-
Those further etherified with alcohols such as propyl alcohol, n-butyl alcohol, i-butyl alcohol, 2-ethylbutanol and 2-ethylhexanol can also be used.

As the amino resin (C), specifically, Uvan 20SE and Uvan 12 manufactured by Mitsui Toatsu Chemicals, Inc.
8, U-Van 220, U-Van 225, U-Van 20S
B, u-van 20SE60, u-van 21R, u-van 22R, u-van 122, u-van 28-60, u-van 20HS, u-van 2028, u-van 202, u-van 120, etc., n-butylated melamine, u-van 62,
U-Van 69-1, U-Van 60R, U-Van 164,
U-Van 165, U-Van 166-60, U-Van 16
9, isobutylated melamine such as uban 2061, butylated urea such as uban 10S-60, uban 10R,
Cymel 303, Cymel 232, Cymel 370, Cymel 325, Cymel 236, Cymel 738, Cymel 771, Cymel 3 manufactured by Mitsui Cyanamid Co., Ltd.
27, Cymel 703, Cymel 701, Cymel 26
6, Cymel 267, Cymel 285, Cymel 23
5, Cymel 238, Cymel 1141, Cymel 27
2, Cymel 254, Cymel 202, Cymel 115
6, Cymel 1158, Cymel 300, Cymel 30
1, high-melt type melamine such as Cymel 350, Cymel 736, etc., and an alkyl etherified melamine resin is preferable. When using high solid type melamine, it is preferable to add a conventional curing catalyst such as, for example, dodecylbenzenesulfonic acid.

Although the curing catalyst may or may not be used in the composition of the present invention, the curability can be improved by using the curing catalyst. Specific examples of the curing catalyst include, for example, dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, polymers of dioctyltin maleate, organotin compounds such as tin octylate; phosphoric acid, monomethyl phosphate, monomethyl Ethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate,
Phosphoric acid or phosphoric acid ester such as diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecyl phosphate; propylene oxide, butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acrylic glycidyl ether, γ-glycidoxypropyl trimethoxysilane, γ Glycidoxypropyltriethoxysilane, γ
-Glycidoxypropylmethyldimethoxysilane,

Embedded image Cardura E manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat 828, Epicoat 1 manufactured by Yuka Shell Epoxy Co., Ltd.
Addition reaction product of an epoxy compound such as 001 with phosphoric acid and / or monoacid phosphate; organic titanate compound; organic aluminum compound such as tris (ethylacetoacetate) aluminum and tris (acetylacetonato) aluminum; tetrabutyl Organic zirconium compounds such as zirconate, tetrakis (acetylacetonato) zirconium, tetraisobutylzirconate, butoxytris (acetylacetonato) zirconium; maleic acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, citric acid, succinic acid acid,
Acidic compounds such as phthalic acid, trimellitic acid, pyromellitic acid, their anhydrides, and paratoluenesulfonic acid;
Hexylamine, di-2-ethylhexylamine, N,
Amines such as N-dimethyldodecylamine and dodecylamine; mixtures or reactants of these amines with acidic phosphate esters; and alkaline compounds such as sodium hydroxide and potassium hydroxide.

Among these curing catalysts, organotin compounds,
Acidic phosphates, mixtures or reactants of acidic phosphates and amines, saturated or unsaturated polycarboxylic acids or their anhydrides, reactive silicon compounds, organic titanate compounds, organic aluminum compounds, organic zirconium compounds or these Is preferred because of its high activity.

These curing catalysts may be used alone or in combination of two or more.

The amount of the curing catalyst used is not particularly limited, but when it is used, the total resin solid content of the components (A), (B) and (C) is 100 parts (parts by weight, hereinafter the same). On the other hand, usually 0.1 to 20 parts is preferable,
-10 parts is more preferred. The amount of curing catalyst used is 0.1
If the amount is less than 20 parts, the curability tends to decrease, and if it exceeds 20 parts, the appearance of the coating film tends to decrease.

Organic polyol (A) used in the present invention
And the alkoxysilyl group-containing acrylic copolymer (B) and the amino resin (C) are heated in a state in which the three are mixed, so that three kinds of crosslinking reactions mainly proceed to form a cured coating film. Express physical properties. One of the crosslinking reactions is a crosslinking reaction in which a siloxane bond (—SiOSi—) is formed by a hydrolysis-condensation reaction of the alkoxysilyl group of the alkoxysilyl group-containing acrylic copolymer (B), and this reaction proceeds even at room temperature. And imparts weather resistance and acid resistance to the cured coating film. The second crosslinking reaction is a siloxy bond by a condensation reaction between the component (B) and the organic polyol (A).

Embedded image This reaction proceeds at about 90 ° C. or higher, and imparts heat curability and appearance of the coating film. However, this reaction tends to deteriorate water resistance. The third crosslinking reaction mainly comprises an ether bond by a condensation reaction between the component (A) and the amino resin (C).

Embedded image This reaction proceeds at about 90 ° C. or higher and imparts heat curability, appearance of the coating film, and scratch resistance, but the weather resistance and acid resistance tend to be inferior due to this reaction. .

Therefore, in order to obtain a thermosetting resin having curability as a thermosetting resin and having weather resistance, acid resistance, and scratch resistance required in the present invention, (A)
The mixing ratio of the three components (B) and (C) is important. The amount of the organic polyol (A) is 69 to 5 parts, preferably 60 to 10 parts, based on 100 parts of the total resin solid content of the components (A), (B) and (C). If it exceeds 69 parts, the decrease in water resistance is remarkable, and if it is less than 5 parts, there are problems in appearance and heat curability. The amount of the alkoxysilyl group-containing acrylic copolymer (B) is 30 to 80 parts, preferably 4 parts.
0 to 70 parts. If the amount is less than 30 parts, the weather resistance and the acid resistance tend to decrease, and if it exceeds 80 parts, the appearance tends to decrease.
The amount of the amino resin (C) is 1 to 15 parts, preferably 3 to 12 parts. If it is less than 1 part, the effect of imparting scratch resistance is small,
If it exceeds 15 parts, the acid resistance is significantly reduced. (B)
The alkoxysilyl group-containing vinyl monomer in the component,
6 to 72% by weight, preferably 8% by weight based on 100% by weight of the total resin solid content of the components (A), (B) and (C).
~ 49% by weight.

The organic polyol (A) of the present invention and an alkoxysilyl group-containing acrylic copolymer (B), or the organic polyol (A) and an amino resin (C), or an alkoxysilyl group-containing acrylic copolymer (B) When the compatibility with the amino resin (C) is poor and a transparent coating film cannot be obtained, it is possible to compatibilize by heating.

The curing temperature of the thermosetting composition of the present invention is 80
° C or higher, preferably 90 ° C or higher, more preferably 100 ° C or higher.
° C or higher. If the temperature is lower than 80 ° C., the curing is insufficient. Also, high-temperature and rapid curing at 150 to 220 ° C. is possible.

The composition of the present invention generally contains a solvent, but the solvent used is not particularly limited as long as it is non-reactive. Specific examples of such a solvent include, for example, aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, alkyl alcohols, ketones, and esters used in general paints and coating agents. ,
Examples include ethers, alcohol esters, ketone alcohols, ether alcohols, ketone ethers, ketone esters, ester ethers, and the like, and alkyl alcohols are preferable in that the storage stability of the composition is improved. . As alkyl alcohols,
Those having 1 to 10 carbon atoms in the alkyl group are preferred, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol, t-butyl alcohol, n- Amyl alcohol, isoamyl alcohol, hexyl alcohol, octyl alcohol, cellosolve and the like are used.

Although there is no particular limitation on the amount of the solvent used,
The amount is preferably 100 parts or less, more preferably 50 parts or less, based on 100 parts of the total resin solid content of the components (A), (B) and (C). The amount of the solvent used depends on the molecular weight or composition of the components (A) and (B),
It is adjusted according to the solid content concentration or viscosity required for practical use.

It is preferable to use a dehydrating agent in order to secure storage stability that does not cause a problem even when used repeatedly over a long period of time. Specific examples of the dehydrating agent include, for example, methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, methyltrimethoxysilane, γ
-Hydrolysable ester compounds such as methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, methyl silicate and ethyl silicate. The dehydrating agent may be added before the polymerization of the alkoxysilyl group-containing acrylic copolymer (B), may be added after the polymerization, or may be added during the polymerization. Although the amount of the dehydrating agent is not particularly limited, it is usually preferably 100 parts or less, more preferably 50 parts or less, based on 100 parts of the total resin solid content of the components (A), (B) and (C).

When the alkyl alcohol and the dehydrating agent are used in combination, the components (A), (B),
There is a remarkable effect on the storage stability when the component (C) and the curing catalyst are stored as a mixture.

The composition of the present invention may contain additives such as diluents, pigments (including extender pigments), ultraviolet absorbers, light stabilizers, anti-settling agents, and leveling agents, depending on the intended use; A fibrous material such as acetate butyrate; a resin such as an epoxy resin, a melamine resin, a vinyl chloride resin, a chlorinated polypropylene, a chlorinated rubber, and polyvinyl butyral; a filler may be added.

The composition of the present invention is applied to an object to be coated by a conventional method such as various kinds of coating, especially dipping, spraying, and brushing.

[0053]

Next, the thermosetting resin composition of the present invention will be described more specifically based on examples. (Parts indicate parts by weight.) Synthesis Example 1 Synthesis of Organic Polyol (A-1) In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen gas inlet tube and dropping funnel, butyl acetate 31. After 3 parts and 9.5 parts of xylene were charged and heated to 110 ° C. while introducing nitrogen gas, 41.2 parts of n-butyl methacrylate, 10.0 parts of stearyl methacrylate,
Placel FM-1 (caprolactone methacrylate manufactured by Daicel Chemical Industries, Ltd., Mw =
244) 48.8 parts, azobisisobutyronitrile (A
A monomer mixture consisting of 4.75 parts of IBN) and 13.4 parts of Solvesso 100 (exxon, a petroleum aromatic solvent) was dropped at a constant rate over 5 hours by a dropping funnel. Thereafter, 0.5 parts of AIBN and 10.0 parts of xylene were added.
Part was dropped at a constant speed over 1 hour, and after 2 hours of polymerization, the mixture was cooled, and xylene was added to the resin solution to give a solid content of 60 parts.
% To obtain a solution of the organic polyol (A-1). The hydroxyl value of the obtained resin is 110 mgKOH
/ G and the number average molecular weight was 5,500.

Synthesis Example 2 Synthesis of Organic Polyol (A-2)
As a monomer mixture, n-butyl methacrylate 4
6.7 parts, 2-ethylhexyl acrylate 21.3
Parts, 26.8 parts of 2-hydroxyethyl methacrylate,
A solution of an organic polyol (A-2) having a solid content of 60% was obtained in the same manner as in Synthesis Example 1 except that a mixture consisting of 6 parts of acrylic acid, 4.75 parts of AIBN, and 13.4 parts of Solvesso 100 was used. . The hydroxyl value of the obtained resin is 1
The number average molecular weight was 5,100 at 15 mgKOH / g.

Synthesis Example 3 Alkyl Containing Alkoxysilyl Group
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen gas inlet tube and dropping funnel, 31.3 parts of dipropylene glycol methyl ether and 9.5 xylene were added. And heated to 110 ° C. while introducing nitrogen gas, then 10.7 parts of styrene and 1 part of n-butyl acrylate
A monomer mixture consisting of 0.0 part, 19.5 parts of methyl methacrylate, 58.8 parts of γ-trimethoxysilylpropyl methacrylate, 1.0 part of acrylamide, 6.46 parts of AIBN and 13.4 parts of Solvesso 100 was added to
The solution was dropped at a constant speed over 5 hours by a dropping funnel. afterwards,
0.5 parts of AIBN and 10.0 parts of xylene were dropped at a constant speed over 1 hour, and after 2 hours of polymerization, the mixture was cooled,
Xylene was added to the resin solution to adjust the solid content to 60% to obtain a solution of an alkoxysilyl group-containing acrylic copolymer (B-1). The number average molecular weight of the obtained resin was 4,300.

Synthesis Example 4 Alkyl Containing Alkoxysilyl Group
As synthetic monomer mixture alcohol copolymer (B-2), 10.7 parts of styrene, 17.6 parts of n- butyl acrylate, methyl methacrylate 4
0.7 parts, γ-trimethoxysilylpropyl methacrylate 30.0 parts, acrylamide 1.0 part, AIBN
A solution of an alkoxysilyl group-containing acrylic copolymer (B-2) having a solid content of 60% was obtained in the same manner as in Synthesis Example 3 except that a mixture consisting of 6.46 parts and 13.4 parts of Solvesso 100 was used. Was. The number average molecular weight of the obtained resin was 4,600.

Synthesis Example 5 Acrylic containing an alkoxysilyl group
As a synthetic monomer mixture of the copolymer (B-3) , 10.7 parts of styrene, 26.0 parts of isobutyl methacrylate, 2.5 parts of methyl methacrylate, 1.0 part of acrylamide, γ-trimethoxysilylpropyl methacrylate 59. 8 copies, AIBN
A solution of an alkoxysilyl group-containing acrylic copolymer (B-3) having a solid content of 60% was obtained in the same manner as in Synthesis Example 3 except that a mixture consisting of 6.46 parts and 13.4 parts of Solvesso 100 was used. Was. The number average molecular weight of the obtained resin was 4,600.

Example 1 91.7 parts (55 parts by solids) of the resin solution (A-1) obtained in Synthesis Example 1 and 50 parts (55 parts by solids) of the resin solution (B-1) obtained in Synthesis Example 3 30 parts), Cymer 232 (manufactured by Mitsui Cyanamid Co., Ltd., methoxy, butoxylated melamine having a solid content of about 100%), 15 parts, 1984-4 (Kusumoto Chemical Co., Ltd.)
Acrylic leveling agent, active ingredient about 50%)
After mixing and stirring 4 parts (1 part of the active ingredient) and 4 parts of a curing catalyst (Nailure 5225, neutralized dodecylbenzenesulfonate amine manufactured by King Industries, USA; about 25% of the active ingredient), the mixture was stirred. Was added to adjust the coating viscosity to 25 seconds (Ford Cup No. 4) to obtain a thermosetting composition. Using this thermosetting composition, a cured coating film was formed as described below, and was subjected to a test.

Examples 2 to 16 and Comparative Examples 1 to 5 Tables 1, 2 and 3 show the composition of the mixture before viscosity adjustment.
(The number of parts is shown in terms of the amount of solid content or the amount of active ingredient.) Except as shown in Example 1, the same procedure as in Example 1 was carried out.
By adjusting to 4), a thermosetting composition was obtained. Using this thermosetting composition, a cured coating film was formed as described below, and was subjected to a test.

(Note) in the table is as follows.

(Note 1) Uban 20SE: a butyl etherified melamine resin solution manufactured by Mitsui Toatsu Chemicals, Inc., solid content: about 60%.

(Note 2) Organic polyol (A-3)
Praxel CD305 manufactured by Daicel Chemical Industries, Ltd. was used. Praxel CD305 has a hydroxyl value of 304 mg
KOH / g polycarbonate triol with about 100% solids.

Conditions for forming a coating film A 0.8 mm thick electrodeposited intermediate coated plate was degreased to prepare a test material. On this material, a commercially available acrylic melamine resin paint (silver metallic base) was applied using an air spray gun so that the cured film thickness became about 10 to 20 μm, and was left at room temperature for about 5 minutes. 1 to 1
The coating materials (thermosetting compositions) of 6 and Comparative Examples 1 to 5 whose viscosity was adjusted were applied using the air spray gun so that the cured film thickness became about 30 to 40 μm, and then set for about 10 minutes. Next, the painted test piece was heated to 140 ° C.
For 30 minutes to obtain a cured coating film. These were subjected to various tests according to the following test methods. The results are shown in Tables 1, 2 and 3.

Test Method Appearance: The finished feeling of the coating film was evaluated from the following criteria based on gloss, smoothness and feeling of holding. …: Very good,…: good, Δ: slightly poor, ×: poor Pencil hardness: Expressed by pencil hardness according to JIS K5400. Acid resistance: A test piece is immersed in a 1% sulfuric acid solution.
After immersion for 4 hours, it was washed with water, the coated surface was observed, and evaluated according to the following criteria. ◎: No abnormality, ○: No abnormality on the painted surface, but a slight level difference was observed at the boundary between the immersed part and the non-immersed part, Δ: Slightly reduced gloss of the painted surface, ×: Whiteness of the painted surface Properties: After immersion in hot water of 80 ° C. for 24 hours, washing was performed with water, the coated surface was observed, and evaluated according to the following criteria. …: No abnormality, ○: Slightly reduced gloss, Δ: Coated surface decreased, X: Coated surface whitened Scratch resistance: A test piece was fixed horizontally, and an abrasive (JIS 8 class) was placed on the test piece. Rohm ± 1.2%, JIS 11 types Rohm ± 1.2%, Kaolin 0.6%, neutral detergent 1.0
%, 96.0% water mixture), and then covered with kraft paper (contact surface diameter 5 cm, load 22 g / cm 2
² ) was stroked on the coating surface. The 20 ° gloss after 0 and 20 strokes was measured with a color difference meter, and the gloss retention was evaluated by its gloss retention (GR). The larger the GR, the better the scratch resistance. Gel fraction: A free clear film obtained by baking at 140 ° C. for 30 minutes was wrapped in a 300 mesh stainless steel wire mesh (W ₀ ) that had been precisely weighed, and weighed precisely (W
₁ ). This was immersed in acetone for 24 hours to extract, dried, and precisely weighed (W ₂ ). The gel fraction was determined according to the following equation.

[0065]

(Equation 1)

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

[0069]

By using the thermosetting resin composition of the present invention, a coating film having good weather resistance, acid resistance, and scratch resistance can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI // C09D 143/04 C09D 143/04 (72) Inventor Hisao Furukawa 4-5-7 Chikushigaoka, Kita-ku, Kobe (56) References JP-A-4-202478 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 43/04 C08L 27/12 C08L 33/00-33/04 C08L 61/20 C08L 67 / 00-67/04 C09D 143/04

Claims (3)

(57) [Claims] (A) a hydroxyl value of 20 to 350 mg KOH
/ G of an organic polyol , and ( B) an alkoxysilyl group-containing vinyl monomer in an amount of 20
Include alkoxysilyl group-containing acrylic copolymer containing 90 wt%, and (C) amino resin as an essential component, including a curing catalyst
A thermosetting resin composition having no (A)
(C) the proportion of each component is (A) component, (B) component and
With respect to 100 parts by weight of the total resin solid content of the component (C), (A)
69 to 5 parts by weight of the component, 30 to 80 parts by weight of the component (B)
Parts, a thermosetting resin set in which the component (C) is 1 to 15 parts by weight
Adult. (A) a hydroxyl value of 20 to 350 mg KOH
/ G of an organic polyol, and (B) an alkoxysilyl group-containing vinyl monomer in an amount of 20
Alkoxysilyl group-containing acrylic containing -90% by weight
Thermosetting resin composition containing copolymer, (C) amino resin, and (D) curing catalyst as essential components
(However, the epoxy compound and the
Except when the adduct with the functional sulfonic acid is used alone.
), The proportion of each of the components (A) to (C) is (A)
, Total resin solid content of component (B) and component (C) 100
Component (A) is 69 to 5 parts by weight, and component (B) is
30 to 80 parts by weight, component (C) 1 to 15 parts by weight
Certain thermosetting resin compositions. 3. An acrylic copolymer containing an alkoxysilyl group.
The united compound is represented by the following formula as a copolymerized monomer: 5 to 70% by weight of the (meth) acrylate represented by
% Of the heat according to claim 1 or 2.
Curable resin composition.