JPH08269369A - Composition for aqueous chipping-resistant coating material - Google Patents

Abstract

PURPOSE: To obtain a composition for an aqueous chipping-resistant coating material comprising a conjugated diene-based particle, a sulfur-based vulcanizing agent and rubber powder, capable of sound attenuating a collision sound occurring by flying stone, etc., when driving, without impairing adhesivity, suitable for an underfloor material of an automobile, etc. CONSTITUTION: This composition for an aqueous chipping-resistant coating material comprises (A) a conjugated diene particle, for example, composed of 55-75wt.% of a conjugated diene monomer such as 1,3-butadiene, 24-45wt.% of acrylonitrile, etc., (B) a sulfur-based vulcanizing agent such as sulfur powder, etc., (C) rubber powder (preferably 0.005-5mm volume-average particle diameter) and further preferably (D) a urethane-resin particle. The blending ratio is preferably 0.5-2.5 pts.wt. of the component B and 20-300 pts.wt. of the component C based on 100 pts.wt. of the component A.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a composition for water-based chipping-resistant paint.

[0002]

2. Description of the Related Art An underfloor of automobiles, a tire house, and the like are coated with a chipping-resistant coating composition in order to protect them from damage caused by flying stones during traveling. Conventionally, non-aqueous (organic solvent-based) ones have been used as chipping-resistant coating compositions, but they have been shifting to aqueous coating compositions due to increasing environmental problems. Acrylic water-based coating compositions are widely known as water-based coating compositions. For example, those containing an acrylic latex and an aluminum pigment (Japanese Patent Laid-Open No. Sho 6-96).
No. 0-147482) or one containing an acrylic resin emulsion and precipitated light calcium carbonate (JP-A-63-172777). The coating film obtained by applying these acrylic water-based coating composition, the chipping resistance is not necessarily sufficient,
In particular, the chipping resistance after the coating film was wet with water during running in the rain was extremely low. Therefore, the present inventor has conducted extensive studies to develop an aqueous coating composition having excellent chipping resistance, and an aqueous coating composition containing conjugated diene polymer particles and a sulfur-based vulcanizing agent is dried and dried. The inventors have found that it gives a coating film having high chipping resistance after wetting and excellent adhesion to a substrate, and filed an application first.

[0003]

DISCLOSURE OF THE INVENTION The present inventor has studied to further improve the performance of the composition for an aqueous chipping-resistant coating, and as a result, in addition to the conjugated diene polymer particles and the sulfur-based vulcanizing agent, a powder has been added. It was found that by adding rubber, it is possible to muffle the collision noise generated by flying stones and the like without impairing chipping resistance and adhesion.
The present invention has been completed based on these findings.

[0004]

Thus, according to the present invention, there is provided a composition for an aqueous chipping-resistant coating material, which comprises conjugated diene polymer particles, a sulfur vulcanizing agent and a powder rubber. Provided. Further, according to the present invention, there is provided a water-based chipping-resistant coating composition characterized by containing urethane resin particles in the water-based chipping-resistant coating composition.

The conjugated diene polymer particles used in the present invention are copolymer particles of a conjugated diene monomer and a monomer copolymerizable therewith.

Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and chloroprene. Can be mentioned. Of these conjugated diene monomers, 1,3-butadiene is preferable. The amount of the conjugated diene monomer is usually 50 to 95% by weight, more preferably 55 to 90% by weight, and further preferably 55 to 75% by weight, based on all the monomers. Fifty
If it is less than wt%, the chipping resistance after wetting with water tends to be lowered.

As the monomer copolymerizable with the conjugated diene monomer, cyano group-containing ethylenically unsaturated monomers such as acrylonitrile, methacrylonitrile, fumaronitrile, α-chloroacrylonitrile and α-cyanoethylacrylonitrile; acryl Acid, methacrylic acid, maleic acid,
Ethylenically unsaturated carboxylic acids such as fumaric acid and citraconic acid and salts thereof; dibutyl maleate, methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylic acid Trifluoroethyl, ethoxyethyl (meth) acrylate,
Ethylenically unsaturated carboxylic acid ester monomers such as hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and 2-sulfopropyl (meth) acrylate; styrene, alkyl Vinyl aromatic monomers such as styrene and vinylnaphthalene; fluoroalkyl vinyl ethers such as fluoroethyl vinyl ether; vinyl pyridine; non-conjugated diene monomers such as vinyl norbornene, dicyclopentadiene and 1,4-hexadiene; ethylene, propylene, etc. Α-olefins; (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-methoxymethyl (meth)
Examples thereof include ethylenically unsaturated amide monomers such as acrylamide and N-propoxymethyl (meth) acrylamide. These monomers can be used alone or in combination of two or more.

Among the monomers copolymerizable with the conjugated diene monomer, a cyano group-containing ethylenically unsaturated monomer, preferably acrylonitrile, is a water-based coating composition obtained by using this monomer. It is preferable because the coating film obtained by coating has high chipping resistance during drying. The amount of the cyano group-containing ethylenically unsaturated monomer is usually 5 to 50% by weight, preferably 10 to 45% by weight, more preferably 25 to 45% by weight, based on the total monomers. Is preferred. If it exceeds 50% by weight, the chipping resistance after wetting with water tends to decrease. Further, of the monomers copolymerizable with the conjugated diene monomer, the amount of the monomers other than the cyano group-containing ethylenically unsaturated monomer is usually 45% by weight or less, preferably 35% by weight or less. , And more preferably 20
% By weight or less. If it exceeds 45% by weight, the chipping resistance during drying and after wetting with water tends to decrease.

The conjugated diene polymer particles used in the present invention are preferably in a latex state because they are easily mixed uniformly with a sulfur vulcanizing agent and the resulting coating film has good adhesion.

The conjugated diene polymer particles have a methyl ethyl ketone insoluble content of usually 50% by weight or more, preferably 60 to 90% by weight, more preferably 60 to 80% by weight. If it is less than 50% by weight, the chipping resistance tends to decrease. The methyl ethyl ketone insoluble matter was obtained by casting a latex of copolymer particles on a glass plate with a frame and leaving it in an atmosphere of 20 ° C. for 48 hours to obtain a film. It is a value expressed as a percentage with respect to the constant weight of the film initially put in the wire mesh after immersing it in methyl ethyl ketone at 20 ° C. for 48 hours and then determining the constant weight of the solid content remaining in the wire mesh.

The glass transition temperature of the conjugated diene polymer particles is usually -60 to 0 ° C, preferably -50 to-.
The temperature is 5 ° C, more preferably -40 to -10 ° C. 0 ° C
If it exceeds, the chipping resistance of the coating film tends to decrease,
Also, cracking is likely to occur. If it is less than -60 ° C, the coating film tends to be sticky and difficult to handle.

The average particle diameter of the conjugated diene polymer particles is usually 100 to 500 nm, preferably 150 to 500 nm.
It is 350 nm. If it exceeds 500 nm, the surface of the coating film tends to be rough and cracks are likely to occur. On the other hand, when it is less than 100 nm, the viscosity of the coating composition becomes high, which is not suitable for practical use.

The conjugated diene polymer particles used in the present invention are usually produced by a radical polymerization method. For example, an emulsion polymerization method, a suspension polymerization method, a solution polymerization method and the like can be mentioned.

The sulfur-based vulcanizing agent used in the present invention is generally used for vulcanizing a conjugated diene polymer. Examples of the sulfur-based vulcanizing agent include powdered sulfur, sulfur flower, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur; sulfur monochloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, N, N′-dithio-bis. (Hexahydro-2H-azepinone-2), sulfur compounds such as thiuram polysulfide, and the like. Of these sulfur-based vulcanizing agents, colloidal sulfur is preferable because cracks are less likely to occur in the coating film and the adhesion is improved. The amount of the sulfur-based vulcanizing agent is usually 0.1 to 5 parts by weight, preferably 0.5 to 100 parts by weight with respect to 100 parts by weight of the conjugated diene polymer particles.
2.5 parts by weight. If it is less than 0.1 part by weight, the chipping resistance of the coating film after being wet with water tends to be lowered. If it exceeds 5 parts by weight, cracking tends to occur.

A vulcanization accelerator is preferably used in combination with the sulfur-based vulcanizing agent. The combined use of a vulcanization accelerator further improves chipping resistance during drying and after wetting with water. Vulcanization accelerators include aldehyde amines, aliphatic amines,
Aromatic amines, thioureas, guanidines, thiazoles; zinc white, activated zinc white, surface-treated zinc white, zinc carbonate, zinc stearate, magnesium oxide litharge, red lead, lead white and the like. Of these vulcanization accelerators, zinc white is preferable because cracks are less likely to occur and adhesion is improved. The amount of the vulcanization accelerator is usually 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the conjugated diene polymer particles. If the amount of the vulcanization accelerator used exceeds 5 parts by weight, the coating film tends to be cracked.

The volume average particle diameter of the powder rubber used in the present invention is usually 10 mm or less, preferably 5 mm or less. If it exceeds 10 mm, the spraying property for spraying the paint becomes poor. Further, the powder rubber has 80% by volume or more of all the particles, and usually has a particle diameter in the range of 0.005 to 5 mm.

The powder rubber of the present invention is a synthetic rubber such as styrene / butadiene rubber, polybutadiene rubber, polyisoprene rubber, acrylonitrile / butadiene rubber, acrylic rubber epichlorohydrin rubber, silicone rubber, fluororubber, hydrogenated nitrile rubber or natural rubber. It is possible to use the above-mentioned rubber powder, or regenerated rubber powder obtained by reprocessing tires, rubber plates, belts, hoses, shoe soles, weather strips and the like. You may use these in mixture of 2 or more types.

The amount of the powdered rubber compounded is usually 5 to 500 parts by weight, preferably 20 to 300 parts by weight, based on 100 parts by weight of the conjugated diene polymer particles. If the amount of the powdered rubber is too small, the sound deadening property will be poor, and if it is too large, the spraying property during coating may be poor.

The water-based anti-chipping coating composition of the present invention further contains urethane resin particles, whereby the chipping resistance and the adhesion are improved. Urethane resin particles are particles of a polymer having a urethane bond formed in the polymer chain by the reaction of a polyisocyanate compound and a polyol compound.

As the polyisocyanate compound, 1,
3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-nephthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl Diphenylmethane-4,4-diphenylmethane diisocyanate, 1,
Aromatic polyisocyanate compounds such as 3-xylylene diisocyanate; 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,
2,4-trimethyl-1,6-hexamethylene diisocyanate, 1,8-octamethylene diisocyanate,
Aliphatic polyisocyanate compounds such as 1,10-decamethylene diisocyanate; 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1-methylcyclohexane-1,3-diisocyanate, 1-methylcyclohexane-1,4 Alicyclic polyisocyanate compounds such as diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate and 1,3-isocyanomethylcyclohexane; and the like.

Examples of the polyol compound include polyester polyols such as condensation products of polyhydric alcohols and polycarboxylic acids, lactone polymers and the like; polyethylene glycol,
Examples thereof include polyether polyols such as polytetramethylene glycol; those obtained by adding alkylene oxide to the above polyester polyols; those obtained by condensing the above polyether polyols and polyvalent carboxylic acid.

The urethane resin particles can be usually obtained by reacting the polyisocyanate compound with the polyol compound and then further reacting with a chain extender. Examples of the chain extender include water, polyhydric alcohol, primary or secondary amine, hydrazine and the like.

The urethane resin particles used in the present invention have an average particle size of usually 10 to 200 nm, preferably 2
It is 0 to 100 nm. If it is less than 10 nm, the viscosity of the coating composition increases, and the workability tends to deteriorate. 2 on the contrary
When it exceeds 00 nm, the coating film obtained using the coating composition is likely to crack.

With respect to the urethane resin particles, the average particle diameter (unit [nm]) of the urethane resin particles is usually 0.1 to 3 times, preferably 0, relative to 100 parts by weight of the conjugated diene polymer particles. . Use an amount (unit [parts by weight]) represented by a numerical value multiplied by 2 to 2. When it exceeds 3 times, the viscosity of the coating composition increases or aggregates are generated, and nitrogen oxides are easily generated during drying, which deteriorates the working environment. As the urethane resin particles, water-based emulsion particles are suitable because they are easily mixed uniformly with the sulfur-based vulcanizing agent and the coating film has good adhesion.

A filler is usually added to the composition for aqueous chipping-resistant coating material of the present invention. Fillers are powdery or granular materials used in water-based paints. Specific examples of the filler include
Talc, calcium carbonate, diatomaceous earth, mica, kaolin,
Examples thereof include barium sulfate, magnesium carbonate, silica, pyrophyllite, alumina, titanium oxide, carbon black, graphite and the like. These fillers can be used alone or in combination of two or more. Of these fillers, kaolin or calcium carbonate is preferable because it has high chipping resistance during drying and after being wet with water.

The amount of the filler is the conjugated diene polymer particles 1
It is usually 10 to 500 parts by weight, preferably 40 to 400 parts by weight, relative to 00 parts by weight. When the amount of the filler is less than 10 parts by weight, the chipping resistance of the coating film when dried tends to decrease. On the other hand, when the amount of the filler is more than 500 parts by weight, it becomes difficult to mix the conjugated diene polymer particles and the filler uniformly, so that the coating work tends to be difficult.

The water-based anti-chipping coating composition of the present invention may further contain, if necessary, a dispersant, a wetting agent, a thickener, a defoaming agent, an anticorrosive agent, an antifreezing agent, a weight reducing agent, and a heat-sensitive gelling agent. Agents and the like can be added.

The composition for aqueous chipping-resistant coating material of the present invention is an aqueous dispersion containing the above-mentioned conjugated diene polymer particles, a sulfur-based vulcanizing agent and powdered rubber, preferably water containing urethane resin particles. It is a dispersion liquid. The dispersion medium of this aqueous dispersion contains water as a main component. In addition to water, the dispersion medium may contain a hydrophilic organic solvent such as alcohol or ketone. The aqueous chipping resistant coating composition of the present invention generally has a solid content of 50 to 90% by weight. If it is less than 50% by weight, the coating film tends to crack, and if it exceeds 90% by weight, the viscosity of the coating composition tends to be high, which is not suitable for practical use.

As a method for preparing the composition for an aqueous chipping resistant coating composition of the present invention, for example, a dispersion machine such as a kneader or a disperser is used to add a latex of conjugated diene polymer particles to a sulfur vulcanizing agent and urethane resin particles. The method of adding and stirring the emulsion of (1); a method of adding the emulsion of urethane resin particles to the latex of the conjugated diene polymer particles, and further adding a sulfur vulcanizing agent and stirring.

The composition for aqueous chipping-resistant coating is usually
After being applied to the surface of a base material such as metal, it is dried and applied.
As a coating method, for example, an airless spray method, a brush coating method, a roll coating method, a spatula coating method, or the like is adopted.
Particularly, the airless spray method is preferably used. As a drying method, there are a baking drying method and a room temperature drying method, but the room temperature drying method is preferable because the occurrence of blisters can be suppressed. In the room temperature drying method, drying is usually performed under a temperature condition of 20 to 70 ° C.

The preferred embodiments of the water-based anti-chipping coating composition of the present invention are as follows. (1) Conjugated diene polymer particles are 5 to 50% by weight of a cyano group-containing ethylenically unsaturated monomer, and conjugated diene monomer 5
0 to 95% by weight and monomers 0 to 4 copolymerizable therewith
The composition for aqueous chipping resistant coatings of the present invention, which is obtained by polymerizing 5% by weight of a monomer. (2) The conjugated diene polymer particles are acrylonitrile 5
-50% by weight, 50-95% by weight of 1,3-butadiene and 0-45% by weight of another ethylenically unsaturated monomer, which is obtained by polymerizing a monomer. The composition for an aqueous chipping-resistant coating composition of the invention. (3) The glass transition temperature of the conjugated diene polymer particles is -6.
The composition for an aqueous chipping-resistant coating material of the present invention, which has a temperature of 0 to 0 ° C. (4) The average particle size of the conjugated diene polymer particles is 100 to
The water-based anti-chipping coating composition of the present invention having a thickness of 500 nm. (5) The aqueous chipping-resistant coating composition of the present invention, wherein the content of insoluble methyl ethyl ketone in the conjugated diene polymer particles is 50% by weight or more. (6) The aqueous chipping-resistant coating composition of the present invention, wherein the sulfur-based vulcanizing agent is colloidal sulfur. (7) The water-based chipping-resistant coating composition of the present invention, wherein a vulcanization accelerator is used in combination with the sulfur-based vulcanizing agent. (8) The aqueous chipping-resistant coating composition according to the above (7), wherein the vulcanization accelerator is zinc white. (9) The aqueous rubber chipping-resistant coating composition of the present invention, wherein the powdered rubber is such that 50% by volume or more of all the particles have a particle diameter in the range of 0.01 to 5 mm. (10) Conjugated diene polymer particles 1 having a powder rubber content
The water-resistant chipping-resistant coating composition of the present invention is characterized in that it is 5 to 500 parts by weight with respect to 00 parts by weight. (11) The average particle diameter of the urethane resin particles is 10 to 200.
The composition for water-based chipping-resistant coating material of the present invention is characterized in that (12) Amount of urethane resin particles represented by a numerical value obtained by multiplying the average particle diameter (unit [nm]) of the urethane resin particles by 0.1 to 3 with respect to 100 parts by weight of the conjugated diene polymer particles. (Unit [parts by weight]) The composition for water-based chipping-resistant paint of the present invention.

[0032]

EFFECTS OF THE INVENTION The water-based chipping resistant coating composition of the present invention can muffle the sound generated by flying stones without impairing the chipping resistance and adhesion of the coating film. It is suitable as a coating material for surface coating of seals, fuel tanks, front aprons, tire houses and the like.

[0033]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The parts and% in these examples are based on weight.

The evaluation method performed in this example will be described below. [Coatability] The aqueous chipping-resistant coating composition was coated with an air spray (caliber 0.5 mm, discharge pressure 4 to 5 kg / cm ² ), and the discharge state from the spray was evaluated by the following ⊚ to ×. ⊚: Can be sprayed uniformly without stress. ◯: There is a feeling of being caught, but it can be sprayed. Δ: Nozzle clogging occurs during work. X: Not a spray

[Finishing Feeling] The state of the coating film after spray coating was visually judged. ⊚: The coating thickness is constant and the coating is uniform. ◯: The coating film thickness has an uneven portion, but wrinkles and cracks do not occur. Δ: Wrinkles and cracks are generated. X: The thickness of the coating film is non-uniform, and wrinkles, cracks, etc. have occurred.

[Chiping resistance during drying] A water-soluble chipping-resistant coating composition is applied by airless spraying to a coating plate obtained by cationic electrodeposition coating on a zinc phosphate-treated plate so that the dry film thickness is about 340 μm. did. Then 1 at 60 ° C
After drying for 0 minutes, it was left at room temperature for one day to obtain a test piece. JIS B0 is attached to the test piece set at an angle of 60 degrees.
The M-4 nut defined in 101 was continuously dropped from a height of 2.5 m, and the total weight of the dropped nuts was measured by the time the substrate was exposed.

[Chiping resistance after wetting with water] A test piece was obtained in the same manner as in the evaluation of chipping resistance during drying. The test piece was immersed in warm water at a temperature of 40 ° C for 7 days, and then dried. Evaluation was performed in the same manner as the evaluation method for chipping resistance.

[Adhesion] A test piece was obtained in the same manner as in the evaluation of chipping resistance during drying, and the coating film of this test piece was scratched off with a spatula and the state of the peeled surface was observed. A: The coating film cannot be easily peeled off. ◯: The peeled surface has undergone cohesive failure. Δ: The peeled surface causes interface destruction. X: The coating film is not adhered to the substrate at all.

[Muffing property of collision sound] The collision sound generated when a steel ball having a diameter of 4.5 mm was collided with the coating film surface at a speed of 50 to 55 km / h was judged. ○: Almost no sound is generated. X: A high metallic sound is generated.

Examples 1 to 8 100 parts latex of conjugated diene polymer particles having the monomer composition shown in Table 1 (solid content conversion), 1 part colloidal sulfur (manufactured by Hosoi Chemical Co., Ltd.), zinc flower (No. 1 zinc flower: Disperse 1 part of a predetermined urethane resin particle (Usumoto Kasei Co., Ltd. urethane resin particle emulsion, average particle diameter 43.1 nm), powder rubber and a dispersant (Demol EP: Kao Co.) 1.5 parts. Mix evenly in the machine. Next, a predetermined amount of calcium carbonate (R heavy carbon, manufactured by Maruo calcium Co .; average particle size 12 μm)
m), kaolin (ST-kaolin, manufactured by Tsuchiya Kaolin;
75 parts of an average particle diameter of 2 μm or less (25%) and 0.2 part of an antifoaming agent (Fomaster VL, manufactured by San Nopco) are gradually added and stirred to prepare a composition for an aqueous chipping-resistant coating having a solid content of 68%. Got The evaluation results of this composition are shown in Table 1.

Control Example An aqueous chipping-resistant coating composition was obtained in the same manner as in Example except that the rubber powder was not used. The evaluation results of this composition are shown in Table 1.

[0042]

[Table 1]

From Table 1, when the water-based chipping resistant coating compositions of the present invention (Examples 1 to 8) were used, the coating film had good chipping resistance and adhesion, and also had sound deadening performance. I understand. On the other hand, it can be seen that when the water-based chipping-resistant coating composition containing no powdered rubber (control example) is used, the coating film has good chipping resistance and adhesion, but no silencing effect can be obtained.

Claims (2)

[Claims] 1. A composition for an aqueous chipping-resistant coating, which comprises conjugated diene-based polymer particles, a sulfur-based vulcanizing agent and powdered rubber. 2. The water-based chipping resistant coating composition according to claim 1, further comprising urethane resin particles.