JP2008045028A - Aqueous aerosol coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an aqueous aerosol coating composition having excellent drying property, water resistance, gasoline resistance, adhesivity, impact resistance, etc., of coating film, and improved aerosol storage stability and an aqueous aerosol coating composition suitably useful for coating by a coating of domestic use, repair coating of industrial product, having a safe coating environment and taking health into consideration. <P>SOLUTION: The aqueous aerosol coating composition comprises a urethane-modified water-dilutable resin obtained by copolymerizing 70-98 parts by wt. of a water-dilutable resin (solid content) having a weight-average molecular weight of 4,000-50,000 with 2-30 parts by wt. of a polyisocyanate resin (solid content). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water-based aerosol coating composition, and more particularly to a water-based aerosol coating composition suitably used for painting with household paint and repair painting of industrial products.

  Conventionally, lacquers have been widely used in the fields of painting with household paints and repair painting of industrial products because they can be dried quickly and easily.

  However, since lacquers use highly flammable organic solvents, there are problems such as global warming due to air pollution, photochemical smog, health problems due to organic solvents, fire hazards, and odor problems.

  In addition, an aerosol paint made of a water-soluble resin is commercially available as a paint for solving these problems. However, such an aqueous aerosol paint needs to use a water-soluble resin that is soluble in an aerosol filling gas and is also soluble in water. Therefore, the resin has a low molecular weight, slow drying at a low temperature, and there are disadvantages that the water resistance, gasoline resistance, adhesion and impact resistance of the coating film are not good.

  In an attempt to eliminate the above disadvantages, a hydroxyl group-containing ethylenically unsaturated monomer is urethanated with a polyisocyanate resin in an aromatic solvent, an ester solvent, a ketone solvent, etc., and then an ethylenically unsaturated monomer, acrylic acid Alternatively, in the case of solution polymerization with an alkyl ester of methacrylic acid or the like, a step of solvent substitution with glycol ether or an alcohol solvent is necessary for water solubilization, which is complicated. In addition, the molecular weight tends to increase, and the water-soluble urethane resin does not dissolve in the aerosol-filled gas, so that it is difficult to form an aerosol due to the occurrence of blisters.

  The present invention has solved the above-mentioned problems, that is, it is excellent in terms of drying properties, water resistance, gasoline resistance, adhesion, impact resistance, etc. of the coating film, and has a good aerosol storage stability. An object of the present invention is to provide a water-based aerosol paint composition that is suitably used for painting with household paints and repair painting of industrial products, and whose painting environment is safe and health-friendly.

  As a result of intensive studies to solve the above problems, the present inventors have obtained a urethane-modified water-dilutable property obtained by copolymerizing a water-dilutable resin having a specific weight average molecular weight range and a polyisocyanate resin at a specific ratio. The inventors have found that the above problems can be solved by using a resin, and have completed the present invention.

  That is, the water-based aerosol coating composition of the present invention comprises 70 to 98 parts by weight of a water-dilutable resin (solid content) having a weight average molecular weight (hereinafter abbreviated as Mw) of 4,000 to 50,000 and a polyisocyanate resin. (Solid content) It is characterized by comprising a urethane-modified water-dilutable resin obtained by copolymerizing 2 to 30 parts by weight.

  In addition, the water-based aerosol coating composition of the present invention is preferably a water-dilutable resin (solid content) 70 to 70 having a Mw of 4,000 to 50,000 produced in a glycol ether solvent or an alcohol solvent. A mixed solution obtained by selectively reacting 2 to 30 parts by weight of a polyisocyanate resin (solid content) to 98 parts by weight of a neutralized 0.03 to 0.30 equivalent part by an amine compound is used as an amine compound. It is characterized by comprising a urethane-modified water-dilutable resin obtained by neutralization with 1.

  The water-based aerosol coating composition of the present invention is suitably used for coating with household paints and repair coating of industrial products. Adhesion to coated objects, drying properties of coating films, water resistance, gasoline resistance, A coating film excellent in impact and the like was obtained.

  The method for producing a urethane-modified water-dilutable resin that can be used in the aqueous aerosol coating composition of the present invention comprises a combination of the following three steps.

  First step (production of water-dilutable resin): a step of radical polymerization of an ethylenically unsaturated monomer in a glycol ether solvent or an alcohol solvent.

  Second step (urethanization step): A step of selectively reacting the water-dilutable resin and the polyisocyanate resin in a glycol ether solvent or an alcohol solvent that is not normally used in the urethanization reaction.

  Third step (water-solubilizing step): a step of dissolving the urethane-modified water-dilutable resin obtained by copolymerization in water.

  The water-dilutable resin produced in the glycol ether solvent or alcohol solvent in the first step has an Mw of 4,000 to 50,000, preferably 5,000 to 30,000. When Mw is lower than 4,000, the water resistance, drying property, impact resistance, gasoline resistance, etc. of the resin are lowered, and the durability of the coating film tends to be deteriorated. Conversely, the Mw is 50,000. In the case of exceeding, the viscosity of the coating is increased, the amount of the diluent is increased, and the solid content is decreased. Therefore, the coating tends to sag, the tomality is deteriorated, and the coating workability is liable to be deteriorated.

  Examples of the water-dilutable resin that can be used in the aqueous aerosol coating composition of the present invention include a water-dilutable acrylic resin. In addition, a water-dilutable alkyd resin, a water-dilutable epoxy resin, and the like can be used.

  Among these, the use of a water-dilutable acrylic resin is preferable in consideration of coating film performance, atomization suitability, stability after aerosolization, and the like. Only one type of water-dilutable resin may be used, or two or more types may be used in combination.

  Examples of the water-reducible acrylic resin that can be used in the aqueous aerosol coating composition of the present invention include, for example, an ethylenically unsaturated monomer, an alkyl ester of acrylic acid or methacrylic acid, a vinyl aromatic compound, acrylonitrile, methacrylonitrile, Acid value obtained by solution polymerization of an unsaturated monomer mixture consisting of one or more selected from the group consisting of saturated carboxylic acid vinyl ester, vinyl halide, butadiene and ethylene in a glycol ether solvent. Is a copolymer having a hydroxyl value of 30 to 80 and Mw of 4,000 to 50,000.

  The reaction apparatus is not particularly limited as long as the above reaction can be performed uniformly. In consideration of the second step and the third step, the reaction apparatus is preferably a reaction kettle equipped with a stirrer.

  In the second urethanization step, a polyisocyanate resin is selectively reacted with a resin obtained by neutralizing a water-dilutable resin with 0.03 to 0.30 equivalent parts by an amine compound.

  The polyisocyanate resins that can be used include 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4 ' -Diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4 ' -Diphenylpropane diisocyanate, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 3,3'- Aromatic diisocyanates such as dimethoxydiphenyl-4,4'-diisocyanate, aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, lysine diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, p -Aliphatic diisocyanates such as xylene diisocyanate and tetramethylxylene diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylene diisocyanate. Also, so-called modified polyisocyanates such as adduct-modified, burette-modified, isocyanurate-modified, uretonimine-modified, uretdione-modified, carbodiimide-modified, etc. of these organic diisocyanates can be used. Furthermore, polyisocyanate resins called so-called polymeric bodies such as polyphenylene polymethylene polyisocyanate and crude toluene diisocyanate can also be used. These organic polyisocyanates can be used alone or in admixture of two or more. Of these organic polyisocyanates, aliphatic and alicyclic polyisocyanates are preferred when considering weather resistance and the like, and hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are most preferred. preferable.

  Examples of the solvent used in the urethanization reaction include glycol ether solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, and propylene glycol monomer ether that are compatible with water, ethylene glycol. A mixture of glycol ether ester solvents such as monomethyl ether acetate and propylene glycol monoethyl ether acetate, ether solvents such as tetrahydrofuran and dioxane, and alcohol solvents such as methanol, ethanol and isopropanol may be used in combination. Can do. Moreover, a urethanization catalyst can be used at the time of a urethanation reaction as needed. Specific examples thereof include organic metal compounds such as dibutyltin dilaurate and dioctyltin dilaurate, organic amines such as triethylenediamine and triethylamine, and salts thereof.

  The reaction temperature at this time is preferably 30 to 120 ° C, more preferably 50 to 100 ° C.

  The basic neutralizing agent for forming the hydrophilic anionic group in the third step of water solubilization is ethylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, triethanolamine, monoethanolamine, dimethylethanolamine. , Organic amines such as diethylethanolamine, and ammonia.

  Of these, preferred are organic amines and ammonia, and particularly preferred are ethylamine, trimethylamine, triethylamine, and ammonia.

  These hydrophilic anionic group-forming groups and active hydrogen group-containing compounds and basic neutralizing agents may be used alone or in combination of two or more.

  The mixing ratio of the water-dilutable resin / polyisocyanate resin is 70/30 to 98/2 (% by weight), preferably 80/20 to 95/5 (% by weight). If the polyisocyanate resin exceeds 30%, the viscosity of the mixed solution becomes high, causing a problem that it cannot be aerosolized. On the other hand, when the amount of the polyisocyanate resin added is less than 2%, the coating film becomes brittle, impact resistance, gasoline resistance, adhesion, durability, etc. deteriorate and the coating film performance is not good.

  In addition to the urethane-modified water-dilutable resin, the water-based aerosol coating composition of the present invention can be made into a paint by ordinary kneading dispersion by adding additives and auxiliaries commonly used in water-based paints as necessary. it can. For example, coloring pigments, extender pigments, rust preventive pigments, dyes, matting agents, antiseptics, fungicides, antibacterial agents, thixotropic agents, antiblocking agents, dispersion stabilizers, thickeners, film-forming aids, leveling Agents, antioxidants, ultraviolet absorbers, inorganic and organic fillers, plasticizers, antistatic agents and the like can be added.

  As the solvent used for coating, solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, and propylene glycol monomethyl ether that are compatible with water can be used. If necessary, an appropriate amount of an alcohol solvent, an ester solvent, an aromatic solvent, or the like in an amount that does not exclude aerosolization and storage stability can be used.

  Water and the above-mentioned solvent are appropriately adjusted so that the viscosity of the water-based aerosol coating composition is 20 to 150 seconds in Ford Cup # 4 to obtain a filled coating material stock solution.

  For example, 100 to 150 ml of this water-based paint whose viscosity has been adjusted and 150 to 200 ml of dimethyl ether as a propellant gas are filled into an aerosol container in a total amount of 300 ml to obtain an aerosol paint.

  EXAMPLES The present invention will be specifically described below using examples, but the present invention is not limited to these. Unless otherwise specified, “parts” and “%” in Examples and Comparative Examples mean “parts by mass” and “% by mass”, respectively.

<Synthesis example of urethane-modified water-dilutable resin>
The amount (part) of propylene glycol monomethyl ether shown in Table 1 was charged into a reaction vessel equipped with a temperature controller, an agitator type stirrer, a reflux condenser, a supply vessel, a thermometer, and a nitrogen introduction tube. Was replaced with nitrogen gas, the temperature was raised to the reaction temperature shown in Table 1, and then the monomer mixture having the composition shown in Table 1 (the amount of each component was part) was reacted while gradually dropping over 3 hours. It was. After completion of the addition, the mixture was further reacted for 2 hours to obtain a water-dilutable resin. The nonvolatile content, the acid value, the hydroxyl value, and Mw of each resin solution of the water-dilutable resins 1 to 5 and the comparative resins 1 and 2 were as shown in Table 1.

  The solution temperature of the water-dilutable resin was kept at 60 ° C., 0.03 to 0.30 equivalent part of triethylamine shown in Table 2 was added for neutralization for 30 minutes, and polyisocyanate resin was further added from the dropping funnel. The reaction was allowed for 30 minutes. After completion of the urethanization reaction, the mixture was neutralized with triethylamine to obtain a urethane-modified water-dilutable resin and a water-dilutable comparative resin.

<Examples 1-5 and Comparative Examples 1-4>
The urethane-modified water-dilutable resins 1 to 5 and the water-reducible comparative resins 1 to 4 are blended in the quantitative ratios shown in Table 3 to adjust the aqueous aerosol coating compositions of Examples 1 to 5 and Comparative Examples 1 to 4. did. Preparation and drying conditions of test pieces coated with these aqueous aerosol coating compositions, aerosol workability of aqueous aerosol coating compositions, appearance of the resulting coating, adhesion, coating hardness, drying, gasoline resistance, Impact resistance and water resistance were evaluated according to the following evaluation methods and evaluation criteria. The evaluation results were as shown in Table 3.

<Creation and drying conditions of test piece>
A steel plate (JIS G 3141) having a size of 150 mm × 70 mm × 0.8 mm was polished with # 280 abrasive paper and degreased with xylol was used as a test piece to be spray-coated. The aerosol coating composition was shaken about 15 times for each aerosol container, and the coating composition was stirred with a stirring ball in the container and spray-coated on the test piece to prepare a coating test piece having a dry film thickness of 20 to 30 microns. Investigate the drying properties after coating, examine the appearance of the coating after drying at 20 ° C for 2 hours, and after drying at 20 ° C for 7 days, adherence of coating, coating hardness, gasoline resistance, impact resistance The water resistance was examined.

<Aerosol workability>
The state of fog and the state of the coated surface when the aerosol paint composition was spray-coated were determined according to the following evaluation criteria.

  ○ The mist is fine and evenly applied.

  Δ: The fog is slightly poor and the coated surface is crusty skin.

  X The fog is poor and the coating surface is uneven.

<Appearance of coating film>
Based on the appearance of JIS K 5600-1-1 coating film, the following evaluation criteria were used.

  ○ The surface is smooth and uniform with no uneven color or gloss.

  Δ: The coated surface has no unevenness of color and no unevenness, and has a rough skin.

  X Color unevenness and glossy unevenness, and uneven coating surface.

<Adhesiveness>
Based on the JIS K 5600-5-6 cross-cut method, 100 square mesh cutter knives were cut at intervals of 2 mm, and the grids remaining after peeling with a cellophane adhesive tape were determined according to the following evaluation criteria.

  ○ It is 100/100.

  Δ: 90-99 / 100.

  X It is less than 90/100.

<Coating hardness>
Based on JIS K 5600-5-4 pencil scratch value, it was determined by the following evaluation criteria based on scratches on the coating film.

  ○ Pencil hardness is H or higher.

  Δ Pencil hardness is HB to F.

  X Pencil hardness is B or less.

<Dry surface>
In accordance with JIS K 5600-3-2 drying time, surface drying was determined according to the following evaluation criteria.

  ○ Within 15 minutes.

  Δ 16 to 30 minutes.

  X It is 31 minutes or more.

<Curing and drying>
Based on JIS K 5600-3-3 drying time, it determined by the following evaluation criteria by hardening drying.

  ○ Within 60 minutes.

  Δ: 61 to 120 minutes.

  X It is 121 minutes or more.

<Impact resistance>
Based on the JIS K 5600-5-3 DuPont type, it was determined by the following evaluation criteria at 1/4 inch × 500 g × height cm.

  ○ It is 30 cm or more.

  Δ 20 cm.

  X 10 cm.

<Water resistance>
Based on JIS K 5600-6-1 water resistance, the immersion time was 18 hours at 20 ° C., and the following evaluation criteria were used.

  ○ There is no discoloration, no reduction in gloss, and no abnormality.

  △ There is a decrease in gloss and small blisters are generated.

  X A bulge has occurred on the entire surface, or peeling has occurred.

<Gasoline resistance>
In accordance with JIS K 5600-6-1 resistance to volatile oil, it was soaked in a regular gasoline for 10 minutes and judged according to the following evaluation criteria.

  ○ There is no loss of gloss and no abnormality.

  Δ: There is a decrease in gloss, and a little dissolution of the coating film is observed.

  X There is a decrease in gloss, and dissolution of the coating is observed.

Claims (3)

  Urethane-modified water obtained by copolymerizing 70 to 98 parts by weight of a water-dilutable resin (solid content) having a weight average molecular weight of 4,000 to 50,000 and 2 to 30 parts by weight of a polyisocyanate resin (solid content). An aqueous aerosol coating composition comprising a dilutable resin.   The water-based aerosol coating composition according to claim 1, wherein the water-dilutable resin is a water-soluble acrylic resin.   3. The aqueous aerosol coating composition having excellent storage stability according to claim 1, wherein the polyisocyanate resin is selectively reacted with the water-dilutable resin in a glycol ether solvent to urethanize the polyisocyanate resin. .