Scrubbing-resistant velvet coating and preparation method thereof

Abstract

The invention relates to a scrubbing-resistant velvet coating and a preparation method thereof. The velvet coating is prepared from the following raw materials in parts by weight: 30 to 40 parts of acrylic emulsion, 10 to 20 parts of waterborne polyurethane dispersion, 1 to 3 parts of hydroxymethyl cellulose modified graphite carbon nitride, 5 to 8 parts of pearl powder, 1 to 3 parts of polydimethylsiloxane, 0.1 to 0.2 part of coalescing agent, 0.4 to 0.6 part of wetting dispersant and 30 to 40 parts of water. The velvet coating disclosed by the invention has excellent scrubbing resistance, and the product has the characteristics of good storage stability, high paint film hardness, good air permeability, high environmental protection performance and the like, so that the application scene of the velvet art coating is greatly widened.

Description

Technical Field

[0001] The invention relates to the field of coatings, in particular to a scrub-resistant velvet coating and a preparation method thereof. Background Art

[0002] Velvet paint is a water-based art paint named for its unique velvety touch and pearl luster. It is not only environmentally friendly and healthy, but also has practical functions such as mildew and antibacterial, and is widely used in wall decoration.

[0003] The surface of the velvet art paint film is smooth and delicate, and the film is thin. In daily life, it is easy to produce obvious scratches and black marks on the surface due to friction caused by furniture movement, cleaning and wiping, and the scratch resistance is poor, which affects the film effect. Conventional art paint can be used with a topcoat varnish to provide protection for the paint film, but the velvet art paint film has a unique pearlescent effect and cannot be used with a topcoat varnish, otherwise it will affect the light and shadow presentation of the pearlescent effect, so it is difficult to effectively improve the scratch resistance. Summary of the invention

[0004] The purpose of the present invention is to provide a scrub-resistant velvet paint and a preparation method thereof in order to overcome the defects of the above-mentioned prior art. The velvet paint of the present invention has excellent scrub resistance, and the product has the characteristics of good storage stability, high paint film hardness, good air permeability and high environmental protection performance, which greatly broadens the application scenarios of velvet art paint.

[0005] The present invention solves the above technical problems through the following technical solutions: The invention provides a scrub-resistant velvet paint, wherein the raw materials thereof include, by weight: 30-40 parts of acrylic emulsion, 10-20 parts of waterborne polyurethane dispersion, 1-3 parts of hydroxymethylcellulose-modified graphite carbon nitride, 5-8 parts of pearl powder, 1-3 parts of polydimethylsiloxane, 0.1-0.2 parts of film-forming aid, 0.4-0.6 parts of wetting dispersant, and 30-40 parts of water; The hydroxymethyl cellulose modified graphite carbon nitride is prepared by the following method: hydroxymethyl cellulose, p-toluenesulfonic acid and graphite carbon nitride are uniformly mixed, and the hydroxymethyl cellulose modified graphite carbon nitride is reacted under the action of ammonium persulfate to obtain the hydroxymethyl cellulose modified graphite carbon nitride.

[0006] The acrylic emulsion may be the acrylic emulsion commonly used in the art, and there is no particular limitation in the present invention.

[0007] Among them, the aqueous polyurethane dispersion is preferably prepared by the following method: in an organic solvent, a polyisocyanate, a polyolefin polyol and a hydrophilic chain extender are subjected to a polymerization reaction to obtain a prepolymer; after the prepolymer is subjected to a neutralization reaction with a neutralizing agent, it is dispersed in water, and then an amine chain extender is added for a chain extension reaction to obtain the aqueous polyurethane dispersion.

[0008] Among them, the polyisocyanate can be various polyisocyanates conventionally used in the art, preferably one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate.

[0009] Among them, the polyolefin polyol is preferably polyisoprene polyol. The number-average molecular weight of the polyisoprene polyol is preferably 3000-3500.

[0010] Among them, the hydrophilic chain extender is preferably one or more of 3-hydroxypropionic acid, dimethylolpropionic acid, dimethylolbutyric acid and dimethylolacetic acid, and further preferably dimethylolpropionic acid.

[0011] Among them, the amine chain extender can be various amines conventionally used in the art, preferably one or more of ethylenediamine, hexamethylenediamine, pentamethylenediamine, and 4,4'-diphenylmethanediamine.

[0012] Among them, the neutralizing agent is preferably an inorganic basic compound, and further preferably one or more of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates.

[0013] Among them, the organic solvent includes one or more of acetone, methyl ethyl ketone, methyl acetate, and toluene.

[0014] Among them, the wetting dispersant is preferably BYK-190.

[0015] Among them, the average particle size of the pearlescent powder is 200-600 mesh. The pearlescent powder can be selected as needed, and the manufacturer for purchase is Fuhe New Materials Technology (Shanghai) Co., Ltd.

[0016] Among them, the weight-average molecular weight of the polydimethylsiloxane is preferably 5000-10000.

[0017] Among them, the film-forming aid is preferably selected from one or more of propylene glycol methyl ether acetate, alcohol ester 12, propylene glycol diacetate, dipropylene glycol butyl ether, ethylene glycol butyl ether, dipropylene glycol butyl ether and propylene glycol monobutyl ether.

[0018] The present invention also provides a preparation method of the above-mentioned scrub-resistant velvet coating, which comprises the following steps: adding water, acrylic emulsion, aqueous polyurethane dispersion, and hydroxymethyl cellulose-modified graphite carbonitride into a stirrer, stirring evenly, and then adding pearlescent powder, polydimethylsiloxane, film-forming aid, and wetting dispersant, and dispersing evenly at high speed.

[0019] Among them, the rotation speed of the high-speed dispersion is preferably 2000-2500 r / min.

[0020] In a preferred embodiment of the present invention, the velvet coating may further include various additives.

[0021] If additives are included, they can be added in the last step of the preparation method.

[0022] Compared with the prior art, the present invention has the following beneficial effects: aiming at the deficiencies of the existing velvet coatings, the velvet coating provided by the present invention has excellent scratch resistance and scrub resistance, and the product has the characteristics of good storage stability, high film hardness, good air permeability, and high environmental protection performance. It can improve the scratch resistance of the film formed by the coating composition while ensuring that the basic properties of the film meet the requirements and do not cause obvious damage to the appearance effect of the film. Specific Embodiments

[0023] The present invention will be described in detail below with reference to specific embodiments.

[0024] Storage stability test: Observe whether there is sedimentation and deterioration after storing the pigment at 20°C and 40°C for 10 weeks, and use it for the color change of the dried coating.

[0025] Freeze-thaw stability test method: First, measure the pH of the coating (measured at 23°C) and its viscosity under shear loads of 10 s-1, 100 s-1, and 1000 s-1 [measured at 23°C using a rotational viscometer (Rheolab QC equipment from Anton Paar, with a C-LTD80 / QC adjustment system)]. Then store 200 g of the corresponding coating in a tightly sealed glass bottle at -18°C for 8 hours, and then keep it at room temperature for 16 hours. Repeat this procedure 4 times. Then measure the pH and viscosity again, and evaluate the sedimentation characteristics of the coating.

[0026] The scratch resistance is tested according to the following method: (1) Use a hard plastic to reciprocally scratch the surface of the film, and observe whether there are scratches on the film; (2) Use a 316 stainless steel cylinder to load 300 g and reciprocally scratch 20 times, and measure the color difference ΔE between the scratched area and the unscratched area with a color difference meter to characterize the degree of blackening of the film; (3)Use a black rubber cylinder to reciprocally scrape 20 times with a load of 300 g. After wiping with a soft cloth, measure the color difference ΔE between the scraped area and the un-scraped area with a color difference meter to characterize the degree of blackening of the paint film.

[0027] The pearlescent powder was purchased from Fuhe New Materials Technology (Shanghai) Co., Ltd. The parts in the following examples all refer to parts by weight. Example 1

[0028] The aqueous polyurethane dispersion of this example was prepared by the following method: (1)Vacuum the round-bottom flask and then fill it with nitrogen. Add 100 polyisoprene polyol, 40 g diphenylmethane diisocyanate, 11.5 g dimethylolpropionic acid, 200 g acetone and 0.2 g dimethyltin bis(neodecanoate), and stir and react at 80 °C until the mass percentage of the NCO group in the mixture reaches 1.2% to obtain a prepolymer; (2)Add the prepolymer obtained in step (1) to acetone, stir evenly, then add an aqueous sodium hydroxide solution and stir and react for 10 min, then add water for dispersion, and then add 8 g of an aqueous ethylenediamine solution and stir for chain extension reaction for 20 min to obtain an emulsion with a pH value of 7.5. Finally, carry out vacuum distillation on the emulsion to separate acetone to obtain the aqueous polyurethane dispersion.

[0029] The hydroxymethylcellulose-modified graphitic carbon nitride of this example was prepared by the following method: First, mix 10 g of hydroxymethylcellulose, 16 g of p-toluenesulfonic acid and 21 g of graphitic carbon nitride evenly in a round-bottom flask. Continue to add 25 mL of 1 mol / L hydrochloric acid solution in an ice bath, stir slowly for 60 min, then add 0.2 g of ammonium persulfate catalyst, continue to react for 48 h, and then wash with deionized water and vacuum filter to obtain hydroxymethylcellulose-modified graphitic carbon nitride.

[0030] The velvet paint of this example was prepared by the following method: Add 30 parts of water, 31 parts of acrylic emulsion, 10 parts of aqueous polyurethane dispersion, and 1 part of hydroxymethylcellulose-modified graphitic carbon nitride to a stirrer, stir evenly, and then add 5 parts of pearlescent powder, 1 part of polydimethylsiloxane (number average molecular weight is 10,000), 0.1 part of film-forming aid (alcohol ester 12), and 0.4 part of wetting and dispersing agent (BYK-190), and disperse at high speed (rotation speed is 2000 r / min) evenly.

[0031] No deposition and deterioration were observed after the velvet paint prepared in this example was stored for 10 weeks, and the viscosity basically did not change after the above freeze-thaw cycle test.

[0032] Coating preparation: First, apply paraffin oil in the mold, and then slowly pour the prepared velvet coating into the mold to a thickness of about 1.0 mm. After the surface is dry, slowly pour the velvet coating again and gently level it. The total thickness of the coating is about 1.5 mm.

[0033] The obtained coating has excellent scrub resistance. There is no abnormality after scrubbing 800 times in water and 1200 times by dry scrubbing. When the film surface is reciprocally scratched 20 times, no obvious scratches are observed; when scratched 20 times under the condition of a stainless steel cylinder, the color difference ΔE is 0.12; when scratched 20 times under the condition of a black rubber cylinder, the color difference ΔE is 0.42. Example 2

[0034] The aqueous polyurethane dispersion of this example is prepared by the following method: (1) Evacuate a round-bottom flask and then fill it with nitrogen. Add 100 polyisoprene polyol, 50 g of hexamethylene diisocyanate, 12.5 g of dimethylolbutyric acid, 200 g of acetone and 0.2 g of dimethyltin bis(neodecanoate), and stir and react at 80 °C until the mass percentage content of the NCO group in the mixture reaches 1.1% to obtain a prepolymer; (2) Add the prepolymer obtained in step (1) to acetone, stir evenly, then add an aqueous sodium hydroxide solution and stir and react for 10 min, then add water for dispersion, and then add 8 g of an aqueous ethylenediamine solution and stir for chain extension reaction for 20 min to obtain an emulsion with a pH value of 7.5. Finally, carry out vacuum distillation on the emulsion to separate out acetone to obtain the aqueous polyurethane dispersion.

[0035] The hydroxymethyl cellulose modified graphitic carbon nitride of this example is prepared by the following method: First, mix 10 g of hydroxymethyl cellulose, 18 g of p-toluenesulfonic acid and 20 g of graphitic carbon nitride evenly in a round-bottom flask, continue to add 25 mL of 1 mol / L hydrochloric acid solution in an ice bath, stir slowly for 60 min, then add 0.3 g of ammonium persulfate catalyst, continue to react for 48 h, and then wash with deionized water and carry out vacuum filtration to obtain hydroxymethyl cellulose modified graphitic carbon nitride.

[0036] The velvet coating of this example is prepared by the following method: Add 40 parts of water, 39 parts of acrylic emulsion, 20 parts of aqueous polyurethane dispersion, and 2 parts of hydroxymethyl cellulose modified graphitic carbon nitride to a stirrer, stir evenly, and then add 8 parts of pearlescent powder, 3 parts of polydimethylsiloxane (number average molecular weight is 10000), 0.2 part of film-forming aid (alcohol ester 12), and 0.6 part of wetting and dispersing agent (BYK-190), and disperse at high speed (rotation speed is 2500 r / min) evenly.

[0037] No deposition and deterioration are observed after the velvet coating obtained in this example is stored for 10 weeks, and the viscosity basically does not change after the above freeze-thaw cycle test.

[0038] Coating preparation: First, apply paraffin oil to the mold, and then slowly pour the prepared velvet coating into the mold to a thickness of about 1.0 mm. After the surface is dry, slowly pour the velvet coating again and gently scrape it flat. The total thickness of the coating is about 1.5 mm.

[0039] The obtained coating has excellent scrub resistance. There is no abnormality after scrubbing 800 times in water and 1200 times by dry scrubbing. When the surface of the paint film is reciprocally scraped 20 times, no obvious scratches are observed; when scraped 20 times under the condition of a stainless steel cylinder, the color difference ΔE is 0.11; when scraped 20 times under the condition of a black rubber cylinder, the color difference ΔE is 0.40.

[0040] It must be emphasized that the above detailed description is a specific description of the feasible embodiments of the present invention, but the embodiments are not intended to limit the patent scope of the present invention. Any equivalent implementation or change made without departing from the technical spirit of the present invention should be included in the patent scope of the present invention.

Claims

1. A scrub-resistant velvet paint, the raw materials of which include, by weight: 30-40 parts of acrylic emulsion, 10-20 parts of waterborne polyurethane dispersion, 1-3 parts of hydroxymethyl cellulose modified graphite carbon nitride, 5-8 parts of pearl powder, 1-3 parts of polydimethylsiloxane, 0.1-0.2 parts of film-forming aid, 0.4-0.6 parts of wetting dispersant, 30-40 parts of water; The hydroxymethyl cellulose modified graphite carbon nitride is prepared by the following method: hydroxymethyl cellulose, p-toluenesulfonic acid and graphite carbon nitride are uniformly mixed, and the hydroxymethyl cellulose modified graphite carbon nitride is reacted under the action of ammonium persulfate to obtain the hydroxymethyl cellulose modified graphite carbon nitride.

2. The scrub-resistant velvet paint according to claim 1, characterized in that: The aqueous polyurethane dispersion is prepared by the following method: in an organic solvent, polyisocyanate, polyolefin polyol and a hydrophilic chain extender are polymerized to obtain a prepolymer; the prepolymer is neutralized with a neutralizing agent, then water is added to disperse the prepolymer, and an amine chain extender is added to carry out a chain extension reaction to obtain the aqueous polyurethane dispersion.

3. The scrub-resistant velvet paint according to claim 2, characterized in that: The polyisocyanate is preferably one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate.

4. The scrub-resistant velvet paint according to claim 2, characterized in that: The polyolefin polyol is polyisoprene polyol; the number average molecular weight of the polyisoprene polyol is preferably 3000-3500.

5. The scrub-resistant velvet paint according to claim 2, characterized in that: The hydrophilic chain extender is preferably one or more of 3-hydroxypropionic acid, dimethylolpropionic acid, dimethylolbutanoic acid and dimethylolacetic acid.

6. The scrub-resistant velvet paint according to claim 2, characterized in that: The amine chain extender is one or more of ethylenediamine, hexamethylenediamine, pentamethylenediamine, and 4,4'-diphenylmethanediamine.

7. The scrub-resistant velvet paint according to claim 2, characterized in that: The neutralizing agent is an inorganic alkaline compound, and more preferably one or more of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates.

8. The scrub-resistant velvet paint according to claim 2, characterized in that: The organic solvent includes one or more of acetone, butanone, methyl acetate and toluene.

9. A method for preparing a scrub-resistant velvet coating as claimed in any one of claims 1 to 8, comprising the following steps: adding water, acrylic emulsion, aqueous polyurethane dispersion, and hydroxymethylcellulose-modified graphite carbon nitride into a stirrer, stirring evenly, and then adding pearl powder, polydimethylsiloxane, film-forming aid, and wetting dispersant, and dispersing evenly at high speed.

10. The preparation method according to claim 9, characterized in that: The rotation speed of the high-speed dispersion is 2000-2500 r / min.