JPH0788471B2 - Stabilizer for thermosetting synthetic resin coatings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stabilizer for paints, specifically, a stabilizer for thermosetting synthetic resin paints containing a specific benzotriazole compound.

[Problems to be Solved by Prior Art and Invention]

BACKGROUND ART Conventionally, paints used outdoors such as automobile exterior paints are required to have long-term weather resistance in addition to general properties such as chemical resistance, solvent resistance, and physical performance. In particular, with the recent social demand for resource saving, the demand for weather resistance has become more advanced, and for example, in the case of passenger cars, coating film guarantee has been required for several years or more.

The polymer compound in the paint forming the coating film is deteriorated by the action of light, causing cracks, deterioration of gloss and discoloration,
The appearance of the coating film is significantly impaired. In addition, in a two-coat, one-bake finish coating film, delamination may occur between the base coat layer and the top coat layer.

In order to solve the above-mentioned drawbacks of the paint, various ultraviolet absorbers are used as light stabilizers. However, these UV absorbers are not fully satisfactory. For example, a benzotriazole-based UV absorber has a good UV-absorbing ability, but has a drawback that it is easily extracted.

[Means for solving problems]

The present inventors have conducted extensive studies in view of the current situation, and as a result, the benzotriazole compound represented by the general formula (I) can stabilize the coating film for a long period of time.
Moreover, they have found that the coating film has almost no coloring, and have reached the present invention.

That is, the present invention provides a stabilizer for a thermosetting synthetic resin coating material comprising a benzotriazole compound represented by the following general formula (I).

(In the formula, R represents a hydrogen atom or an alkyl group, R ₁ represents a hydrogen atom or a methyl group, and X represents —O—, —CH ₂ NH—, —O.
CH ₂ CH ₂ O-, _{-CH 2 O -, - CH 2} CH 2 O -, - CH 2 CH 2 COOCH 2 CH 2 O- or Indicates. ) Hereinafter, the stabilizer for thermosetting synthetic resin coating material of the present invention will be described in detail.

In the benzotriazole compound represented by the general formula (I) which constitutes the stabilizer of the present invention, the alkyl group represented by R is methyl, ethyl, propyl, isopropyl, sec-butyl, t-butyl, t- Amyl, sec-amyl, hexyl, heptyl, t-octyl, nonyl, decyl, undecyl and the like can be mentioned.

Therefore, examples of the benzotriazole compound represented by the general formula (I) that constitutes the stabilizer of the present invention include the following compounds.

(Compound abbreviation) BT-1: [2-hydroxy-3- (acryloylaminomethyl) -5-methylphenyl] benzotriazole BT-2: [2-hydroxy-3- (methacryloylaminomethyl) -5-t-butyl Phenyl] benzotriazole BT-3: [2-hydroxy-3- (acryloylaminomethyl) -5-t-octylphenyl] benzotriazole BT-4: (2-hydroxy-4-acryloyloxyphenyl) benzotriazole BT-5 : [2-hydroxy-4- (methacryloyloxyethoxy) phenyl] benzotriazole BT-6: [2-hydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) phenyl] benzotriazole BT-7: [2- Hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) fe Benzotriazole BT-8: [2-hydroxy-5- (acryloyloxymethyl) phenyl] benzotriazole BT-9: [2-hydroxy-3-t-butyl-5- (methacryloyloxyethyl) phenyl] benzotriazole BT-10: [2-hydroxy-3-t-butyl-5- (acryloyloxyethoxycarbonylethyl) phenyl] benzotriazole BT-11: [2-hydroxy-3-t-butyl-5-
{(Methacryloyloxy-2-hydroxypropoxy) carbonylethyl} phenyl] benzotriazole A benzotriazole compound represented by the above general formula (I), which is used as a stabilizer in the invention (hereinafter referred to as a benzotriazole compound of the invention). Since it can bind to the resin component in the thermosetting synthetic resin paint, the compatibility or extractability, which has been a drawback of conventional stabilizers, has been significantly improved. Can be stabilized.

The benzotriazole compound of the present invention can be combined with a resin component by blending it in a usual thermosetting synthetic resin coating material and curing it after coating, but in advance,
It is also possible to use a copolymer with a monomer having a polymerizable unsaturated bond used as a synthetic resin component for paint, and use this copolymer as it is or together with other resin components as a resin component for paint.

The amount of the benzotriazole compound of the present invention used is usually
It is about 0.01 to 10% by weight with respect to the resin component (solid content) in the paint, and when used as a copolymer with other monomers, it is used so as to have the above proportion with respect to the solid content. When using the copolymer with other resin components,
The proportion of the benzotriazole compound in the copolymer may be higher and can be used, for example, up to 50% by weight. When the benzotriazole compound of the present invention is used as a copolymer with other monomers and this copolymer is used together with other resin components, the total amount of solids in the coating material, including other resin components, is It is advisable to adjust the proportion of the benzotriazole compound of the invention to the above proportion (about 0.01 to 10% by weight).

When the amount of the benzotriazole compound of the present invention is 0.01% by weight or less based on the solid content, the stability of the coating film is insufficient, and even when it is 10% by weight or more, the stability is improved to the extent commensurate with it. Instead, it may even adversely affect the physical properties of the coating film.

Examples of the monomer having another polymerizable unsaturated bond copolymerized with the benzotriazole compound of the present invention include, for example,
Styrene, acrylonitrile, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-butyl methacrylate, 3-methacrylic acid tertiary
Butyl, 2-ethylhexyl methacrylate, lauryl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-acrylic acid acrylate
Ethylhexyl, lauryl acrylate, vinyltoluene, α-methylstyrene, dimethylstyrene, (meth)
Acrylamide, N-methylol (meth) acrylamide, vinyl acetate, diethyl maleate, dibutyl maleate, diethyl fumarate, dibutyl fumarate, dibutyl itaconic acid, 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid 2-hydroxypropyl, polyethylene glycol mono (meth) acrylate, ethylene glycol di (meth) acrylate, glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, ethylglycidyl (meth) acrylate, (meth) acrylic acid, (Anhydrous) maleic acid, fumaric acid, itaconic acid, monobutyl maleate, monobutyl fumarate, monobutyl itaconic acid and the like. These monomers may be used either individually or in combination of two or more.

The copolymer of the benzotriazole compound of the present invention and each of the above monomers can be easily obtained by a known method such as an emulsion polymerization method, a suspension polymerization method, and a bulk polymerization method, but is manufactured by a solution polymerization method. Is very convenient. Polymerization in this case is usually carried out in a solvent, and as such a solvent, a hydrocarbon solvent such as toluene, xylene, ethylbenzene, or ethylcyclohexane or a mixture thereof; an alcohol solvent such as n-butanol; ethyl acetate, An ester solvent such as butyl acetate; a ketone solvent such as methyl isobutyl ketone; or an ether alcohol solvent such as cellosolve may be used alone or in combination of two or more.

In this case, the temperature is normally room temperature to 200 ° C., and the reaction time is 2 to 30 hours.

As the polymerization initiator, a peroxide such as benzoyl peroxide or di-tertiary butyl peroxide;
Alternatively, an azo compound such as azobisisobutyronitrile is used.

Further, if necessary, the molecular weight can be adjusted by using a chain transfer agent such as lauryl mercaptan or octyl thioglycolate.

In addition, the copolymer thus obtained may be modified, for example, with an unsaturated polyester resin, an alkyd resin, an epoxy resin, or a natural or synthetic fatty acid, at the time of its production or after its production, if necessary. .

The copolymer thus obtained has a number average molecular weight of about 10
Those in the range of 100 to 100,000 are preferable.

The thermosetting synthetic resin coating material stabilized by the stabilizer comprising the benzotriazole compound of the present invention includes, for example, a thermosetting synthetic resin coating material using an acrylic resin, an alkyd resin or an unsaturated polyester resin as a substrate. These may optionally be modified with melamine / formaldehyde resins, epoxy resins or polyisocyanates.

The stabilizer comprising the benzotriazole compound represented by the general formula (I) of the present invention may be a usual additive for paints such as other light stabilizers, antioxidants, plasticizers, if necessary. Flow regulator, curing accelerator, thickener, dispersant, pigment,
It can be used together with dyes, antistatic agents and the like.

The resin coating form in which the stabilizer of the present invention can be used is solvent type, liquid solventless type, water-soluble type, water-dispersion type, powder, etc., and can be appropriately selected according to the purpose and application. .

〔Example〕

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 In this example, the effect of the stabilizer of the present invention was observed on a two-layer metallic luster coating comprising a base coat containing a metallic pigment and a transparent top coat.

a) Base coat paint 100 g of methyl methacrylate, 66 g of n-butyl acrylate,
Take 30 g of 2-hydroxyethyl methacrylate, 4 g of methacrylic acid, 80 g of xylene and 20 g of n-butanol, and add 110
2 g of azobisisobutyronitrile with heating and stirring at ℃
A solution consisting of 0.5 g of dodecyl mercaptan, 80 g of xylene and 20 g of n-butanol was added dropwise over 3 hours. Then, the mixture was stirred at the same temperature for 2 hours to prepare an acrylic resin solution having a resin solid content of 50%.

12 parts by weight of the acrylic resin solution, butoxylated methylol melamine (manufactured by Mitsui Toatsu Co., Ltd .; Uban 20SE60; resin solid content 6)
0%) 2.5 parts by weight, cellulose acetate butyrate resin (20% butyl acetate solution) 50 parts by weight, aluminum pigment (Toyo Aluminum Co .; Alpaste 1123N) 5.5 parts by weight, xylene 10 parts by weight, butyl acetate 20 parts by weight and 0.2 parts by weight of copper phthalocyanine blue was taken as a base coat paint.

b) Topcoat paint 100 g of methyl methacrylate, 66 g of n-butyl acrylate,
30 g of 2-hydroxyethyl methacrylate, 4 g of methacrylic acid, 2 g of stabilizer (see Table 1 below), 80 g of xylene and 20 g of n-branol are taken, and 2 g of azobisisobutyronitonil and dodecyl are heated and stirred at 110 ° C. Mercaptan 0.
A solution consisting of 5 g, xylene 80 g and n-butanol 20 g was added dropwise over 3 hours. Then, the mixture was stirred at the same temperature for 2 hours to prepare an acrylic resin solution having a resin solid content of 50%.

48 parts by weight of the acrylic resin solution, 10 parts by weight of butoxylated methylol melamine, 10 parts by weight of xylene and 4 parts by weight of butyl glycol acetate were taken as a top coat paint.

The base coat paint was sprayed onto a primer-treated steel sheet to a dry film thickness of 20 μ, and after standing for 10 minutes, the top coat paint was sprayed to a dry film thickness of 30 μ. After leaving it for 15 minutes, it was baked at 140 ° C. for 30 minutes to prepare a test piece.

This test piece was put in a weatherometer, and the time until cracking of the coating film was generated was measured. The results are shown in Table 1 below.

Example 2 As a top coat paint, coconut oil modified alkyd resin (manufactured by Dainippon Ink & Co .; Betucozol 1323; resin solid content 60%) 70
Parts by weight, butoxylated methylol melamine (Uban 20SE
60) A sample was prepared in the same manner as in Example 1 except that a mixture of 30 parts by weight and 1.0 part by weight of a stabilizer (see Table 2 below) was used.

This test piece was put in a weatherometer, and the time until cracking of the coating film was generated was measured. The results are shown in Table 2 below.

Example 3 20 g of styrene, 20 g of methyl methacrylate, 20 g of butyl acrylate, 22 g of 2-ethylhexyl methacrylate, 15 g of 2-hydroxyethyl methacrylate, 3 g of methacrylic acid and 3 g of a stabilizer (see Table 3 below) were added to azobisisobutyrate. Copolymerization in xylene using ronitrile was performed to prepare an acrylic resin solution having a solid content of 50%.

15 parts by weight of the above acrylic resin solution, 3 parts by weight of butoxylated methylol melamine (Uban 20SE60), 2 parts by weight of epoxy resin (Adekaresin EP-13 manufactured by Asahi Denka Co., Ltd.), 6 parts by weight of aluminum pigment (Alpaste 1123N) and xylene 1
0 part by weight was mixed well to obtain a paint.

The above paint was sprayed onto a primer-treated steel plate so that the dry coating film had a thickness of 40 μm, left for 10 minutes, and then baked at 140 ° C. for 30 minutes to prepare a test piece.

The test piece was put in a weatherometer and the gloss (60 degree gloss) after irradiation for 3000 hours was measured. The results are shown in Table 3 below.
Shown in.

Example 4 75 parts by weight of polyester resin (manufactured by Bayer; L / Ue6108),
Blocked polyisocyanate (Made by Bayer; L / Ue610
9) 25 parts by weight, titanium dioxide 30 parts by weight, phthalocyanine blue 1 part by weight and stabilizer (see Table 4 below) 1.5 parts by weight, a mixed solvent of toluene 70 parts by weight, xylene 80 parts by weight and butyl acetate 100 parts by weight. Dispersed well into the paint.

The above paint was sprayed onto a primer-treated steel plate to a dry film thickness of 30 μ, left for 15 minutes, and then baked at 180 ° C. for 30 minutes to prepare a test piece.

This sample was put in a weatherometer and the gloss after irradiation for 1000 hours was measured. The results are shown in Table 4 below.

[Effect of the invention] The stabilizer for thermosetting synthetic resin coatings of the present invention can be combined with the resin component in the thermosetting synthetic resin coating, so that the compatibility or extractability, etc. Is remarkably improved, the coating film of the paint can be stabilized for a long period of time, and the coating film is hardly colored.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Nakajima 5-2-13 Shirahata, Urawa-shi, Saitama ADEKA ARGUS CHEMICAL CO., LTD. (56) Reference JP-A-58-87144 (JP, A) Kaisho 58-185677 (JP, A)

Claims (1)

[Claims] 1. A stabilizer for a thermosetting synthetic resin coating material comprising a benzotriazole compound represented by the following general formula (I). (In the formula, R represents a hydrogen atom or an alkyl group, R ₁ represents a hydrogen atom or a methyl group, and X represents —O—, —CH ₂ NH—, —O.
CH ₂ CH ₂ O-, _{-CH 2 O -, - CH 2} CH 2 O -, - CH 2 CH 2 COOCH 2 CH 2 O- or Indicates. )