JPH01104669A - Water-base paint composition having high glossiness - Google Patents

Abstract

PURPOSE:To obtain the title composition having excellent appearance, adhesivity and corrosion resistance and suitable for the mending of automobile, by compounding a synthetic resin emulsion vehicle with a specific amount of diethylene glycol mono-tert-butyl ether. CONSTITUTION:The objective composition is produced by compounding (A) 100pts.wt. (in terms of solid resin component) of a vehicle composed mainly of a synthetic resin emulsion [preferably a synthetic resin emulsion having a glass transition temperature of 0-70 deg.C and produced by the emulsion polymerization of 80-99.9wt.% of an ethylenic unsaturated monomer free from functional group and 0.1-20wt.% of an ethylenic unsaturated monomer having functional group] with (B) 5-50pts.wt. of diethylene glycol mono-tert-butyl ether.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a high-gloss aqueous paint composition comprising diethylene glycol monotertiary butyl ether in a synthetic resin emulsion, and particularly to a glossy aqueous paint composition for automobile refinishing. It is useful as a.

[Conventional technology] In general, water-based gloss paints are already commercially available.

Many of the water-based glossy paints that have been proposed so far are paints that use water-soluble resins such as alkyd resins and acrylic resins as vehicles.

Furthermore, when a synthetic resin emulsion is used, gloss is achieved by using a low pigment volume concentration, lowering the molecular weight of the polymer, or using a large amount of solvent. Also, a method has been discovered in which gloss is produced by reducing the particle size of a synthetic resin emulsion.

However, the glossy paint obtained by the above invention has various drawbacks. For example, paints using a water-soluble resin as a vehicle have a low molecular weight and are alkali-soluble, so they have the disadvantage of poor water resistance, alkali resistance, and gloss retention.

In addition, paints that use synthetic resin emulsions as vehicles to obtain gloss by lowering the molecular weight of polymers have the disadvantage of poor physical properties such as water resistance, alkali resistance, solvent resistance, and gloss retention due to their small molecular weights. .

Furthermore, paints that use large amounts of solvent to give them a glossy
Although it gives a glossy shine, there are problems with pollution due to the solvent and the risk of explosion and fire, making it difficult to use. The method of producing gloss by reducing the particle size of the synthetic resin emulsion considerably improves the gloss, but has the disadvantage that specular gloss cannot be obtained.

[Problems to be Solved by the Invention] As a result of various studies in order to obtain a water-based glossy paint free of the above-mentioned drawbacks, the present inventors discovered that diethylene glycol monotertiary was added to a vehicle mainly composed of a synthetic resin emulsion. It was discovered that a water-based high-gloss paint could be obtained by incorporating butyl ether, and the present invention was completed.

[Means for Solving the Problems] That is, the present invention provides 5 to 5 parts of diethylene glycol monotertiary butyl ether per 1.00 parts by weight of the resin solid content in a vehicle mainly composed of a synthetic resin emulsion.
Regarding the high-gloss water-based paint containing 0 parts by weight, the above-mentioned drawbacks of conventional gloss paints have been eliminated.

In addition, as a synthetic resin emulsion, 80 to 99.9% by weight of ethylenically unsaturated monomers without functional groups and 0.1 to 20% by weight of ethylenically unsaturated monomers having functional groups are polymerized. By using a synthetic resin emulsion having a glass transition temperature of 0 to 70°C, a high-gloss aqueous paint composition was obtained which has practical corrosion resistance and is useful for automotive repair.

[Function] In the present invention, the diethylene glycol monotertiary butyl ether blended into the synthetic resin emulsion is
It provides a high-gloss water-based paint without the conventional drawbacks, but the reason for this is unknown. However, although diethylene glycol mononormal butyl ether, which has been conventionally used as a thinner, is similar to the above compound of the present invention,
Since it does not give good results, it is thought that the presence of tert-butyl group is the cause of the favorable effect.

The present invention will be explained in detail below.

The synthetic resin emulsion used in the present invention is not limited to Tokden, but includes styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, vinylidene chloride copolymer, vinyl acetate copolymer, and acrylic ester copolymer. Typical examples include synthetic resin emulsions such as styrene and acrylic acid ester copolymers. Among them, 8 ethylenically unsaturated monomers without functional groups
A synthetic resin emulsion with a glass transition temperature of 0 to 70°C obtained by emulsion polymerization of 0 to 99.9% by weight and 0.1 to 20% by weight of an ethylenically unsaturated monomer having a functional group is
It is particularly useful for automobile repair.

Ethylenically unsaturated monomers without functional groups include vinyl acetate, vinyl propionate, vinyl stearate,
Vinyl esters such as vinyl laurate; acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate; methyl methacrylate, ethyl methacrylate, methacrylic acid Methacrylic acid esters such as butyl, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate; unsaturated carboxylic acids or unsaturated polyhydric acids such as methyl crotonate, ethyl crotonate, dibutyl maleate, diethyl fumarate, etc. Carboxylic acid esters; Representative examples include one or more of acrylonitrile, methacrylonitrile, styrene, methylstyrene, chlorostyrene, vinyl chloride, vinylidene chloride, and ethylene.

In addition, examples of ethylenically unsaturated monomers having functional groups include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid; unsaturated carboxylic acids such as acrylamide and methacrylamide; Amides; N-methylol unsaturated carboxylic acid amides such as N-methylol acrylamide and N-methylol acrylamide; unsaturated glycidyl compounds such as glycidyl acrylate and glycidyl methacrylate; hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxy vinyl ether, etc. One or more types of alkylolated unsaturated compounds can be used. The suitable proportions for use thereof are 80 to 99.9% by weight of ethylenically unsaturated monomers without functional groups and 0.1 to 20% by weight of ethylenically unsaturated monomers having functional groups. .

0.1% by weight of ethylenically unsaturated monomers with functional groups
If it is less than that, the adhesion to metals such as iron plates and aluminum plates will be poor. Moreover, if it exceeds 20% by weight ff1%, it is not preferable because adhesion, water resistance, corrosion resistance, etc. are significantly reduced due to free functional groups.

The synthetic resin emulsion of the present invention can be obtained by conventional emulsion polymerization. The emulsifier used in this case is
Substances with surfactant properties such as anionic surfactants, nonionic surfactants, cationic surfactants, reactive emulsifiers, acrylic oligomers, and water-soluble polymer substances are listed, and one or more of these may be used. Can be used together. This emulsifier is not particularly limited, but is usually used in an amount of 0.1 to 10% by weight based on the total amount of monomers.

On the other hand, as the polymerization initiator, any polymerization initiator generally used in emulsion polymerization can be used. Examples include water-soluble inorganic peroxides or persulfates such as hydrogen peroxide and potassium persulfate; organic peroxides such as cumene peroxide and benzoyl peroxide; and azo compounds such as azobisisobutyronitrile. Type 1 or 2
Used in combination with more than one species. The amount used is about 0.1 to 2% based on the total amount of monomers.

Note that a method generally known as a redox ball method may be used in which these catalysts are used in combination with metal ions and reducing agents.

In addition, a pH adjuster, a polymerization chain transfer agent, etc. can be used within a range that does not impair the purpose of the present invention.

As the pH adjuster, acids such as hydrochloric acid, phosphoric acid, boric acid, and carbonic acid, and their salts, and bases such as alkali metal hydroxides, aqueous ammonia, and amines are used.

Examples of polymerization chain transfer agents include mercaptan, carbon tetrachloride,
Chloroform etc. can be used as necessary.

The polymerization method can be either a batch method or a continuous polymerization method. The polymerization reaction temperature is usually in the range of 30 to 90°C.

The copolymer obtained by such emulsion copolymerization must have a glass transition temperature in the range of 0 to 70°C.

If the glass transition temperature (hereinafter referred to as Tg point) is less than 0° C., the water resistance will not be sufficient, the film will remain sticky, and the stain of the paint film will be significant, which is undesirable. 70
If it exceeds .degree. C., it is not preferable because film forming properties are poor and it is difficult to obtain a tough coating film.

The Tg point of the resin in the present invention is the temperature at which various properties of the amorphous polymer suddenly change, and below this temperature, the motion of the molecular segments of the amorphous part of the polymer is frozen. A common method is to measure the expansion, plot the specific volume against each temperature, and find the temperature at the bend in the resulting curve.

However, in practice, it is as described on pages 66 to 68 of ``Physical Properties and Applications of Niijima Molecular Bunko 14R Synthetic Resin Emulsion'' published by Kobunshi Publishing Association on August 20, 1978. If the Tg point value of the resin composed of each individual monomer is known, the Tg point value of the copolymer resin is
It can be calculated using the following formula.

Tg Tg 1g2 Wl: Weight fraction of component 1 W2: 2 Tgl: Tg point of component 1 single polymer T g 2: ~ 2 Here, Wl+W21 ml.

Examples described in the same book (margins below) Seven polymers - 1g polyethyl acrylate - 22°C Polybutyl acrylate - 52°C Poly 2-ethylhexyl acrylate - 88°C
Listen 1
05°C Polyvinyl acetate 30°C The Tg point of the synthetic resin used in the composition of the present invention is determined from the above formula.

The diethylene glycol monotertiary butyl ether used in the present invention is commercially available and can be used without distillation.

The content of diethylene glycol monotertiary butyl ether is desirably 5 to 50 parts by weight or 10 to 30 parts by weight based on 100 parts by weight of the solid content of the synthetic resin emulsion.

If the content of diethylene glycol monotertiary butyl ether is less than 5 parts, a desirable high-gloss paint cannot be obtained. On the other hand, if the content of diethylene glycol monotertiary butyl ether exceeds 50 parts by weight, the paint will dry slowly, become sticky, and lack practical use.

The method for producing the high-gloss water-based paint of the present invention involves mixing diethylene glycol monotertiary butyl ether and additives such as pigments, dispersants, and viscosity modifiers into a synthetic resin emulsion, using a ball mill, sand mill, high-speed mill, colloid mill, disper, etc. It is made into a paint using a dispersing device or stirring device.

The pigment used in the present invention may be any pigment that has been conventionally used in paints and can be dispersed in water, such as titanium oxide, calcium carbonate, clay, talc, pallite, red iron, white carbon, carbon Inorganic pigments such as black and organic pigments such as azo pigments and phthalocyanine pigments are used. Further, as a dispersant, any dispersant may be used as long as it is used for cross-section coatings, for example,
Inorganic dispersants such as sodium hexametaphosphate and sodium tripolyphosphate, and organic dispersants such as polycarboxylic acid anionic surfactants and nonionic surfactants can be used singly or in combination.

Viscosity modifiers include cellulose derivatives such as methylcellulose, ethylcellulose, hydroxyethylcellulose, and hydroxypropylmethylcellulose, as well as polyvinyl alcohol, casein, guar gum, carrageenan, sodium alginate, polyacrylic acid, polyacrylic acid amide, acrylic resin, and epoxy resin. Synthetic resins such as polyester resins, urethane resins, etc., either alone or as copolymers, may be modified to be water-soluble.

In addition to the above-mentioned additives, various additives may be added to the high-gloss coating composition of the present invention as long as they do not impair the object of the present invention. These additives include coating aids (e.g. dibutyl phthalate, texanol butyl rubitol, butyl cellosolve), freeze stabilizers (e.g. ethylene glycol, methanol), flash inhibitors (e.g. sodium nitrite), preservatives, anti-piping agents. It is possible to add an agent, a wetting agent, and an antifoaming agent as appropriate.

The coating material of the present invention can be diluted with water to an appropriate viscosity, if necessary, and applied by a known general method such as brushing, roller coating, or spraying. The high-gloss water-based paint composition of the present invention can be applied to various base materials such as general building materials such as concrete mortar, lightweight materials such as ALC boards and plasterboards, metals such as iron plates and aluminum plates, and wood materials such as veneers. It is.

In particular, high-gloss water-based paint compositions whose main component is a synthetic resin emulsion obtained by copolymerizing an ethylenically unsaturated monomer with no functional group and an ethylenically unsaturated monomer with a functional group are particularly useful for automobiles. Although it is particularly useful for chassis parts, it can of course also be used for metals other than automobiles, such as iron plates and aluminum plates.

[Examples] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 Water 1
06 parts hydroxyethyl cellulose 2. ■〃
Ammonia water 0.4 parts Nobuco 8034L (antifoaming agent manufactured by San Nopco) 2.
1/l Nobuco Wet 50 (Wetting agent manufactured by San Nobuco) OJ Ethylene glycol 18.11' Amolden FS147 1.0 Nobuco Santo K (Dispersing agent manufactured by San Nobuco) 8.0 Titanium
R-930259" Texanol was added sequentially according to a blending ratio of 24/0 or more, and after stirring at high speed for 30 minutes in a pot using a disper to fully disperse the pigment, Polysol AP-3500 (Styrene- 581 parts of acrylic acid ester emulsion (50%) diethylene glycol monotertiary butyl ether 80'' were added and mixed with stirring to produce a high-gloss water-based paint of the present invention.

This paint was applied to a glass plate with an 8 mil applicator and the 60° gloss was measured to be 89.

Comparative Example 1 A coating material was produced by excluding diethylene glycol monotertiary butyl ether from Example 1 and using the same formulation and operation. The gloss of this paint on a glass plate was 82.

Example 2 Polysol PS-10 (50% vinyl acetate emulsion manufactured by Showa Kobunshi Co., Ltd.) was used in place of Polysol AP-3500 in Example 1, and the same formulation and operation as in Example 1 were carried out to produce a high-gloss paint.

The 600 gloss of this paint on a glass plate was 80.

Comparative Example 2 A paint was produced from Example 2 by removing diethylene glycol monotertiary butyl ether.

The 60° gloss of this paint on a glass plate was 73.

Example 3 A high-gloss paint was produced by using Polysol AP-50 (acrylic acid ester emulsion 50%, manufactured by Showa Kobunshi Co., Ltd.) in place of Polysol AP-3500 in Example 1 and carrying out the same formulation and operation as in Example 1. .

The 60° gloss of this paint on a glass plate was 83.

Comparative Example 3 A paint was produced from Example 3 by removing diethylene glycol monotertiary butyl ether.

The 80" gloss of this paint on a glass plate was 77.

As described above, a high-gloss paint can be obtained by containing diethylene glycol monotertiary butyl ether.

Example 4 Into a flask equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, 1.7 parts of sodium alkylbenzenesulfonate and 317 parts of water were charged, and after raising the internal temperature to 80°C, 238 parts of styrene was added. , 2ethylhexyl acrylate 10
0 parts, 24 parts of methacrylic acid, 8 parts of sodium alkylbenzenesulfonate, 10 parts of polyoxyethylene alkyl phenyl ether, and a seven-summer emulsion previously emulsified in a homomixer with water and 1.7 parts of potassium persulfate were dissolved in 50 parts of water. The mixture was added dropwise at a constant rate over 3.5 hours. After the dropwise addition was completed, the temperature was maintained for 1.5 hours and stirring was continued to complete the reaction. After cooling, 4.2 parts of ammonia water was added to adjust the PL to obtain a milky white synthetic resin emulsion. The resulting synthetic resin emulsion had a pH of -8.5, a solids concentration of 41%, and a viscosity of 2000 (
30°C BH type). The calculated Tg of the resin is:
It is 29°C.

Hereinafter, this will be abbreviated as "composition (■)".

Composition (I) was made into a paint according to the paint formulation described in Table 1 a. The results are shown in Table-2.

Comparative Example 4 Composition (1) was used to form a coating according to the coating composition described in b of Table 1. The results are shown in Table-2.

Example 5 A synthetic resin emulsion was obtained in the same manner as in Example 1 except that the types of monomers in Example 4 were changed as shown below.

Methyl methacrylate 100 parts
Chin 100 parts Butyl acrylate H8 parts Methylylic acid 24 parts The calculated Tg of the resin is 20°C. This is referred to as "composition (■)".

The composition (n) was made into a paint according to the paint formulation described in Table 1a. The results are shown in Table-2.

Comparative Example 5 Composition (n) was made into a paint according to the coating composition shown in a in Table 1, except that diethylene glycol mono-normal butyl ether was used instead of diethylene glycol mono-tertiary butyl ether.

The results are shown in Table-2.

Reference Example A synthetic resin emulsion was obtained in the same manner as in Example 4, except that the types of monomers in Example 1 were changed as shown below.

Stain
308 parts 2-ethylhexyl acrylate 30 parts methoxylic acid 24 parts The calculated Tg of the resin is 78°C. This was made into a paint according to the paint formulation described in a in Table 1. The results are shown in Table-2.

water 1
5"15" Butyl Cellosolve Q/
I 13 //Methanol
4//4//
Diethylene glycol monotertiary butyl ether 8
- Texanol (Kodak Co., Ltd. membrane auxiliary agent) 9 91
1D B P 2
1/2/l SN Thickener A60B (Thickener manufactured by San Nobuco Co., Ltd.) 0.5110.5'' After making it into a paint, adjust it to 200 cps (BL type 10 rpa+) with water.

Table 2 [Note] Paint film performance test method The paint that had been left for 3 hours after preparation was sprayed onto a cold rolled steel plate - Bright (spec-B, 70 x 150 x o, 8 mm) with a diameter of 1.2 mm and a spray pressure of 2. kg
/ cJ, coating thickness 20-30μm) 20℃, 65%
Dry at RH for 24 hours before entering each test.

l) Gloss 60'' Gloss: Using a digital variable angle gloss meter manufactured by Suga Test Instruments ■, measure the gloss at three locations: top, middle, and bottom of the coated plate, and take the average value as the gloss.

Appearance Evaluated by second sight 2) Goban test: Insert the base marks at 1m intervals, apply Nichiban tape and rub it with your fingers 3 to 4 times. Adhesion strength is indicated by the number of .

3) Water resistance After immersing in water at 20°C for 24 hours, observe whitening and blistering of the coating film.

4) Salt water spray resistance Tested according to JIS Z-2371. After 48 hours, observe the rust width blister condition at the cross-cut portion.

As shown in Table 2, an automobile refinishing paint having a Tg in the range of 0 to 70°C and containing diethylene glycol monotertiary butyl ether exhibits high gloss and is excellent in other physical properties.

All paints that do not contain diethylene glycol monotertiary butyl ether have a yuzu peel appearance.

Further, resins with a Tg exceeding 60°C cannot form a continuous coating film and are inferior in adhesion, water resistance, and salt spray resistance.

[Effects of the Invention] The high-gloss water-based paint composition of the present invention has high gloss and excellent appearance, adhesion, and corrosion resistance, and is applicable to various substrates such as concrete, iron, and wood, and is particularly suitable for automobiles. Useful for repair purposes.

Patent applicant: Showa Kobunshi Co., Ltd.

Claims (2)

[Claims] (1) A high-gloss aqueous coating composition comprising 5 to 50 parts by weight of diethylene glycol monotertiary butyl ether based on 100 parts by weight of the resin solid content in a vehicle mainly composed of a synthetic resin emulsion. (2) As a synthetic resin emulsion, 80 to 99.9% by weight of ethylenically unsaturated monomers without functional groups and 0.1 to 20% by weight of ethylenically unsaturated monomers having functional groups
2. The high-gloss aqueous coating composition according to claim 1, which uses a synthetic resin emulsion having a glass transition temperature of 0 to 70° C. obtained by emulsion polymerization of .