Liquid wax modified polyacrylic acid wood paint and preparation method thereof

Abstract

The invention relates to a liquid wax modified polyacrylic acid wood paint and a preparation method thereof, and belongs to the technical field of polymer materials. The liquid wax modified polyacrylic acid wood paint comprises, by weight, 29.9-36.25 parts of core layer monomer, 21.81-27.95 parts of shell layer monomer, 0.3-1.5 parts of diacetone acrylamide, 0.3-0.8 parts of adipic acid dihydrazide, 0.06-0.18 parts of polymerization initiator, 0.46-0.7 parts of emulsifier, 0.5 parts of organic amine ester, 43.7-51 parts of deionized water, 1-5 parts of modified toughening agent, and 1-3 parts of flame retardant; the liquid wax modified polyacrylic acid wood paint prepared by the invention not only has excellent heat resistance and flame retardant effect, but also has good tensile and bending strength.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a liquid wax modified polyacrylic acid wood paint and a preparation method thereof. Background Art

[0002] Water-based acrylic emulsion is popular due to its high solid content, quick drying, waterproof and water-whitening resistance, and good weather resistance. However, during the use of water-based acrylic emulsion, the paint film is prone to high-temperature tackiness, low-temperature brittleness, and poor toughness. Therefore, it is necessary to improve the water-based acrylic emulsion to enhance its comprehensive performance.

[0003] The commonly used modification method for polyacrylic emulsion is chemical modification. Chemical modification refers to the addition of specific monomers to improve the performance of the emulsion without affecting the stability of the emulsion. However, traditional polyacrylic wood paint is prone to cracking during use, affecting normal use. In addition, although liquid wax modified polyacrylic wood paint has certain flame retardancy, with the increase in actual application needs, its own flame retardancy no longer meets the needs. Therefore, the development of a liquid wax modified polyacrylic wood paint with excellent performance has important practical significance and application value. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a liquid wax modified polyacrylic acid wood paint and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A liquid wax modified polyacrylic acid wood paint, comprising the following raw materials in parts by weight: 29.9-36.25 parts of a core layer monomer, 21.81-27.95 parts of a shell layer monomer, 0.3-1.5 parts of diacetone acrylamide, 0.3-0.8 parts of adipic acid dihydrazide, 0.06-0.18 parts of a polymerization initiator, 0.46-0.7 parts of an emulsifier, 0.5 parts of an organic amine ester, 43.7-51 parts of deionized water, 1-5 parts of a modified toughening agent, and 1-3 parts of a flame retardant; Furthermore, the core layer monomer is prepared from the following components in the following weight ratios: 8-10 parts of methyl methacrylate, 7-9 parts of butyl acrylate, 0.2-0.25 parts of methacrylic acid, 7 parts of N-hydroxymethyl acrylamide, and 7.7-10 parts of Fischer-Tropsch wax solution; Furthermore, the shell monomer is prepared from the following components in the following weight ratios: 8-10 parts of methyl methacrylate, 7-9 parts of butyl acrylate, 0.2-0.25 parts of methacrylic acid, 7.5-8 parts of 2-hydroxyethyl methacrylate, and 8-10 parts of styrene; Furthermore, the diacetone acrylamide and adipic acid dihydrazide are emulsion polymerization cross-linking reagents; Furthermore, the polymerization initiator is potassium persulfate; Furthermore, the emulsifier is nonylphenol polyoxyethylene ether; Furthermore, the organic amine ester is a neutralizing agent.

[0006] The modified toughening agent is prepared by the following method: Step A1: maleic anhydride, toluene and 3-chloroaniline were mixed, stirred for reaction for 30 minutes, tetrahydrofuran was added, and stirring was continued for 5 minutes in an ice-water bath, and triethylamine was added, and the mixture was reacted for 10 minutes, washed, dried, filtered, and rotary evaporated to obtain a compound; Further, the dosage ratio of maleic anhydride, toluene, 3-chloroaniline, tetrahydrofuran, and triethylamine is 4.81-5.02 g: 40-50 mL: 6.28-6.49 g: 10 mL: 3.11-4.58 g; First, maleic anhydride is reacted with the amino group of 3-chloroaniline to synthesize the compound; Step A2: 3-aminopropyltrimethoxysilane and ethanol are mixed and stirred for 30 minutes, and then the compound, acetone and triethylamine are added and mixed, and the mixture is stirred at room temperature for 2-3 hours, and then rotary evaporated, washed and dried to obtain an intermediate product; Further, the usage ratio of 3-aminopropyltrimethoxysilane, ethanol, compound, acetone, and triethylamine is 8.95-17.93 g: 200 mL: 10-12 g: 20 mL: 0.5-1 g; Secondly, the amino group of 3-aminopropyltrimethoxysilane reacts with the chlorine atom of the compound to synthesize an intermediate product; Step A3: the intermediate product and the ethanol-water mixed solution were mixed at 35° C. for 10 min, toluene and toluene diisocyanate were added under nitrogen protection, mixed evenly, and reacted at 80° C. for 2 h to obtain a modified toughening agent; Further, the usage ratio of the intermediate product, the ethanol-water mixed solution, toluene, and toluene diisocyanate is 0.02-0.04 mol: 150 mL: 20-40 mL: 7.5-15 g, and the volume ratio of ethanol to water in the ethanol-water mixed solution is 4:1; Finally, the modified toughening agent is synthesized by using the hydrolyzed silanol group of the intermediate product to react with the isocyanate group of toluene diisocyanate to form a urethane bond.

[0007] The flame retardant is prepared by the following method: Step B1: Add phenylphosphonic acid and anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, heat to 110°C for reaction for 1 hour, continue to heat to 150°C for reaction for 8 hours, evacuate for 0.5 hour, cool, add acetone, wash, filter and vacuum dry to obtain a piperazine derivative; Further, the dosage ratio of phenylphosphonic acid, anhydrous piperazine, and acetone is 7.6-11.4 g: 8.5-10.1 g: 45-65 mL; First, piperazine and phenylphosphonic acid are used to undergo an acylation reaction to synthesize piperazine derivatives; Step B2: 3-Butenetriethoxysilane and ethanol were mixed, stirred at 80° C. for 10 h, and then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added, stirred for 12 h, cooled to room temperature, filtered, and washed to obtain a pre-product; Further, the usage ratio of 3-butenetriethoxysilane, ethanol, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 0.05-0.08 mol: 200 mL: 0.05-0.08 mol; Secondly, the carbon-carbon double bond of 3-butylenetriethoxysilane is reacted with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to synthesize a pre-product; Step B3: After the pre-product and the ethanol-water mixed solution are mixed at 35°C for 10 minutes, a piperazine derivative is added, and the mixture is reacted at 100°C for 5 hours. The temperature is then adjusted to 25°C, and triethylamine, toluene and diphenylphosphine chloride are added dropwise to mix. After the addition is complete, the temperature is slowly raised to 90°C, and the mixture is kept at this temperature for 3 hours. The mixture is cooled and dried to obtain a flame retardant. Further, the dosage ratio of the preproduct, the ethanol-water mixed solution, the piperazine derivative, triethylamine, toluene, and diphenylphosphine chloride is 0.04-0.06 mol: 150 mL: 0.02-0.03 mol: 7.5 g: 50-80 g: 13.5-20.3 g, and the volume ratio of ethanol to water in the ethanol-water mixed solution is 4:1; Finally, the silanol groups after hydrolysis of the pre-product are used to react with the chlorine atoms of diphenylphosphine chloride, and then the remaining silanol groups are used to react with the chlorine atoms of diphenylphosphine chloride to synthesize the flame retardant.

[0008] A method for preparing a liquid wax modified polyacrylic acid wood paint comprises the following steps: S1. Preparation of core layer monomer pre-emulsion and shell layer monomer pre-emulsion At room temperature, 28.4-33.65 parts of core layer monomer, 0.2-0.3 parts of emulsifier and polymerization initiator aqueous solution are added into reaction kettle 1, wherein the polymerization initiator aqueous solution is prepared by mixing 0.03-0.08 parts of polymerization initiator with 6-7 parts of deionized water, and stirred at a stirring speed of 1000-1200 rpm for 15-25 minutes to obtain a core layer monomer pre-emulsion; At room temperature, 21.81-27.95 parts of shell monomer and 0.1-0.17 parts of emulsifier are added to a reaction kettle 2 containing 6-7 parts of deionized water, and stirred at a stirring speed of 1000-1200 rpm for 15-25 minutes to obtain a shell monomer pre-emulsion; S2. Preparation of seed emulsion At room temperature, in the reaction kettle 3, add 0.02-0.05 parts of polymerization initiator, 0.16-0.2 parts of emulsifier and 25.7-28 parts of deionized water, adjust the rotation speed to 500-600rpm, and stir for 0.5-1h; then raise the temperature to 75-80°C, reduce the rotation speed to 300-400rpm, and evenly add 1.5-2.6 parts of core layer monomer to the reaction kettle 3 within 15-20min, react for 0.5-1h, and wait for the emulsion to emit blue light to obtain the seed emulsion; S3. Preparation of nuclear layer emulsion At a temperature of 75-80°C and a rotation speed of 500-600 rpm, the core layer monomer pre-emulsion in reactor 1 is added dropwise to the seed emulsion in reactor 3 within 1.5-2 hours, and the temperature is kept for 0.5-1 hour to form a core layer emulsion; S4. Mix the shell monomer pre-emulsion, the core layer emulsion and the polymerization initiator aqueous solution, keep the temperature at 75-80°C for 1.5-2.5h, then lower the temperature to room temperature, add 0.3-1.5 parts of diacetone acrylamide, 1-5 parts of modified toughening agent, 1-3 parts of flame retardant and adipic acid dihydrazide aqueous solution, add 0.5 parts of organic amine ester dropwise to adjust the pH value to 7-9, stir for 20-30min, and prepare liquid wax modified polyacrylic acid wood paint, wherein the polymerization initiator aqueous solution is prepared by mixing 0.01-0.05 parts of initiator and 4-6 parts of deionized water, and the adipic acid dihydrazide aqueous solution is prepared by mixing 0.3-0.8 parts of adipic acid dihydrazide and 2-3 parts of deionized water.

[0009] Beneficial effects of the present invention: The liquid wax modified polyacrylic wood paint of the present invention improves the molecular structure characteristics of the core layer monomer by adding a Fischer-Tropsch wax solution to the core layer monomer during the core monomer-shell monomer polymerization reaction, wherein the Fischer-Tropsch wax solution has the properties of improving the gloss, durability, hardness and wear resistance of the product, and enhancing water resistance and drug resistance. The shell layer monomer is synthesized by adding a styrene monomer to the shell layer monomer, and the excellent transparency and rigidity of styrene are used to improve the mechanical properties of the shell layer monomer, as well as the easy processing performance of styrene, thereby reducing production costs and improving cross-linking polymerization efficiency.

[0010] In the modified toughening agent prepared by the present invention, the maleimide group enhances the flexibility of the acrylic acid molecular chain due to its flexibility, forms an interpenetrating network structure, effectively relieves stress concentration, and thus improves the toughness of the material. At the same time, the group has a dipole moment perpendicular to the main axis of the molecular chain, which effectively enhances the interaction between molecules, thereby increasing the glass transition temperature and melting point of the material, thereby increasing the heat resistance of the molecular chain. In addition, the synthesized N-phenylmaleimide, as a five-membered cyclic monomer, has a 1,2-disubstituted vinyl structure, which can increase the internal rotation resistance of the macromolecular chain, enhance the thermal stability of the material, prevent the material from decomposing or oxidizing in a high temperature environment, and extend the service life of the material. In addition, the silanol group produced by the hydrolysis of the intermediate product combines with the isocyanate group to form a polyurethane, and its unique soft and hard segment structure gives the material high strength and high elasticity, effectively improves the crosslinking density of acrylic acid, reduces brittleness, and significantly enhances toughness.

[0011] The flame retardant prepared by the present invention forms a -Si-O- crosslinking system, which effectively prevents the escape of combustion products and inhibits the thermal degradation of polymer materials, thereby achieving low smoke flame retardancy; wherein, dichlorophenyl phosphate contains phosphorus element, which can form phosphate compounds during combustion, synthesize a protective layer, inhibit the spread of flame, and thus achieve a flame retardant effect; at the same time, dichlorophenyl phosphate has good compatibility with acrylic acid, ensuring the uniform distribution and long-term stability of the flame retardant in the material; the pyrophosphate piperazine derivative effectively plays the role of carbon source in polypropylene, and cooperates with the phosphorus nitrogen flame retardant to achieve low smoke flame retardancy. At the same time, by constructing an expanded carbon layer, oxygen and fire sources are effectively blocked, resulting in a synergistic flame retardant effect. In addition, the phosphorus-nitrogen flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, as a phosphaphenanthrene compound with high thermal stability, can effectively flame retard in the condensed phase and the gas phase, promote the formation of a dense and continuous carbon layer, isolate oxygen and heat exchange, and further enhance the flame retardant effect; in addition, the flame retardant prepared by the present invention is halogen-free, helps to reduce pollution to the environment and damage to the ecosystem, is harmless to human health, and achieves sustainable development. DETAILED DESCRIPTION

[0012] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] Embodiment 1: A method for preparing a liquid wax modified polyacrylic acid wood paint, comprising the following steps: S1, weighing raw materials by weight, adding 28.4 parts of core layer monomer, 0.2 parts of emulsifier and polymerization initiator aqueous solution into reaction kettle 1 at room temperature, wherein the polymerization initiator aqueous solution is prepared by mixing 0.03 parts of polymerization initiator with 6 parts of deionized water, and stirring at a stirring speed of 1000 rpm for 15 minutes to obtain a core layer monomer pre-emulsion; At room temperature, 21.81 parts of shell monomer and 0.1 parts of emulsifier were added into a reaction kettle 2 containing 6 parts of deionized water, and stirred at a stirring speed of 1000 rpm for 15 minutes to obtain a shell monomer pre-emulsion; S2. At room temperature, in a four-necked flask reactor 3 equipped with a condenser, a thermometer, a stirring paddle and a constant pressure dropping funnel, 0.02 parts of a polymerization initiator, 0.16 parts of an emulsifier and 25.7 parts of deionized water were added, the rotation speed was adjusted to 500 rpm, and stirred for 0.5 h; then the temperature was raised to 75°C, the rotation speed was reduced to 300 rpm, and 1.5 parts of a core layer monomer was uniformly added dropwise to the reactor 3 within 15 min, and the reaction was carried out for 0.5 h. When the emulsion showed blue light, the seed emulsion was obtained; S3, at a temperature of 75°C and a rotation speed of 500 rpm, within 1.5 hours, the core layer monomer pre-emulsion in reactor 1 is added dropwise to the seed emulsion in reactor 3, and the temperature is kept for 0.5 hours to form a core layer emulsion; S4, the shell monomer pre-emulsion, the core layer emulsion and the polymerization initiator aqueous solution in the reaction kettle 2 are mixed, kept at 75-80°C for 1.5-2.5h, and then the temperature is lowered to room temperature, 0.3 parts of diacetone acrylamide, 1 part of modified toughening agent, 1 part of flame retardant and adipic acid dihydrazide aqueous solution are added, 0.5 parts of organic amine ester are added dropwise to adjust the pH value to 7, and stirred for 20min to obtain liquid wax modified polyacrylic acid wood paint, wherein the polymerization initiator aqueous solution is prepared by mixing 0.01 parts of initiator and 4 parts of deionized water, and the adipic acid dihydrazide aqueous solution is prepared by mixing 0.3 parts of adipic acid dihydrazide and 2 parts of deionized water; The modified toughening agent is prepared by the following method: Step A1: 4.81 g of maleic anhydride, 40 mL of toluene and 6.28 g of 3-chloroaniline were mixed, stirred for reaction for 30 min, 10 mL of tetrahydrofuran was added, and the mixture was continuously stirred for 5 min in an ice-water bath, and 3.11 g of triethylamine was added, and the mixture was reacted for 10 min. The mixture was washed, dried, filtered, and rotary evaporated to obtain a compound; Step A2: 8.95 g of 3-aminopropyltrimethoxysilane and 200 mL of ethanol were mixed and stirred for 30 min, and then 10 g of the compound, 20 mL of acetone and 0.5 g of triethylamine were added and mixed, and the mixture was stirred at room temperature for 2 h, and then rotary evaporated, washed and dried to obtain an intermediate product; Step A3: 0.02 mol of the intermediate product and 150 mL of an ethanol-water mixed solution were mixed at 35° C. for 10 min, 20 mL of toluene and 7.5 g of toluene diisocyanate were added under nitrogen protection, mixed evenly, and reacted at 80° C. for 2 h to obtain a modified toughening agent, wherein the volume ratio of ethanol to water in the ethanol-water mixed solution was 4:1; The flame retardant is prepared by the following method: Step B1: Add 7.6 g of phenylphosphonic acid and 8.5 g of anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, and heat to 110° C. for reaction for 1 h. Continue to heat to 150° C. for reaction for 8 h, evacuate for 0.5 h, cool, add 45 mL of acetone, wash, filter, and vacuum dry to obtain a piperazine derivative; Step B2: 0.05 mol of 3-butylenetriethoxysilane and 200 mL of ethanol were mixed, stirred at 80° C. for 10 h, and then 0.05 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added, stirred for 12 h, cooled to room temperature, filtered, and washed to obtain a pre-product; Step B3: After mixing 0.04 mol of the preproduct and 150 mL of an ethanol-water mixed solution at 35°C for 10 min, 0.02 mol of a piperazine derivative was added, and the mixture was reacted at 100°C for 5 h. The temperature was then adjusted to 25°C, and 7.5 g of triethylamine, 50 g of toluene and 13.5 g of diphenylphosphine chloride were added dropwise. After the addition was completed, the mixture was slowly heated to 90°C, and the mixture was kept warm for 3 h. The mixture was cooled and dried to obtain a flame retardant. The volume ratio of ethanol to water in the ethanol-water mixed solution was 4:1.

[0014] Embodiment 2: A method for preparing a liquid wax modified polyacrylic acid wood paint, comprising the following steps: S1, weighing raw materials by weight, adding 30 parts of core layer monomer, 0.25 parts of emulsifier and polymerization initiator aqueous solution into reactor 1 at room temperature, wherein the polymerization initiator aqueous solution is prepared by mixing 0.05 parts of polymerization initiator with 8 parts of deionized water, and stirring at a stirring speed of 1100 rpm for 20 minutes to obtain a core layer monomer pre-emulsion; At room temperature, 24.88 parts of shell monomer and 0.2 parts of emulsifier were added into a reactor 2 containing 7 parts of deionized water, and stirred at a stirring speed of 1100 rpm for 20 minutes to obtain a shell monomer pre-emulsion; S2. At room temperature, in a four-necked flask reactor 3 equipped with a condenser, a thermometer, a stirring paddle and a constant pressure dropping funnel, 0.04 parts of a polymerization initiator, 0.15 parts of an emulsifier and 27 parts of deionized water were added, the rotation speed was adjusted to 550 rpm, and stirred for 0.7 h; then the temperature was raised to 75°C, the rotation speed was reduced to 350 rpm, and 2 parts of the core layer monomer were uniformly added dropwise to the reactor 3 within 17 min, and the reaction was carried out for 0.7 h. When the emulsion showed blue light, the seed emulsion was obtained; S3, at a temperature of 76°C and a rotation speed of 550 rpm, within 1.7 hours, the core layer monomer pre-emulsified liquid in reactor 1 is added dropwise to the seed emulsion in reactor 3, and the temperature is kept for 0.7 hours to form a core layer emulsion; S4, the shell monomer pre-emulsion, the core layer emulsion and the polymerization initiator aqueous solution in the reaction kettle 2 are mixed, kept at 77°C for 2h, and then the temperature is lowered to room temperature, 1.15 parts of diacetone acrylamide, 3 parts of modified toughening agent, 2 parts of flame retardant and adipic acid dihydrazide aqueous solution are added, 0.5 parts of organic amine ester are added dropwise to adjust the pH value to 8, and stirred for 25min to obtain liquid wax modified polyacrylic acid wood paint, wherein the polymerization initiator aqueous solution is prepared by mixing 0.012 parts of initiator and 4 parts of deionized water, and the adipic acid dihydrazide aqueous solution is prepared by mixing 0.48 parts of adipic acid dihydrazide and 2 parts of deionized water; The modified toughening agent is prepared by the following method: Step A1: 4.9 g of maleic anhydride, 45 mL of toluene and 6.30 g of 3-chloroaniline were mixed, stirred for reaction for 30 min, 10 mL of tetrahydrofuran was added, and the mixture was stirred for 5 min in an ice-water bath, and then 3.84 g of triethylamine was added, and the mixture was reacted for 10 min. The mixture was washed, dried, filtered, and rotary evaporated to obtain a compound; Step A2: 13.44 g of 3-aminopropyltrimethoxysilane and 200 mL of ethanol were mixed and stirred for 30 min, and then 11 g of the compound, 20 mL of acetone and 0.75 g of triethylamine were added and mixed, and the mixture was stirred at room temperature for 2.5 h, and then rotary evaporated, washed and dried to obtain an intermediate product; Step A3: 0.03 mol of the intermediate product and 150 mL of an ethanol-water mixed solution were mixed at 35° C. for 10 min, 30 mL of toluene and 9 g of toluene diisocyanate were added under nitrogen protection, mixed evenly, and reacted at 80° C. for 2 h to obtain a modified toughening agent, wherein the volume ratio of ethanol to water in the ethanol-water mixed solution was 4:1; The flame retardant is prepared by the following method: Step B1: Add 9.5 g of phenylphosphonic acid and 9.3 g of anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, and heat to 110° C. for reaction for 1 h. Continue to heat to 150° C. for reaction for 8 h, evacuate for 0.5 h, cool, add 55 mL of acetone, wash, filter, and vacuum dry to obtain a piperazine derivative; Step B2: 0.065 mol of 3-butylenetriethoxysilane and 200 mL of ethanol were mixed, stirred at 80° C. for 10 h, and then 0.065 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added, stirred for 12 h, cooled to room temperature, filtered, and washed to obtain a pre-product; Step B3: After mixing 0.05 mol of the pre-product and 150 mL of an ethanol-water mixed solution at 35°C for 10 min, 0.025 mol of a piperazine derivative was added, and the mixture was reacted at 100°C for 5 h. The temperature was then adjusted to 25°C, and 7.5 g of triethylamine, 65 g of toluene and 16.9 g of diphenylphosphine chloride were added dropwise. After the addition was completed, the mixture was slowly heated to 90°C, and the mixture was kept warm for 3 h. The mixture was cooled and dried to obtain a flame retardant. The volume ratio of ethanol to water in the ethanol-water mixed solution was 4:1.

[0015] Embodiment 3: A method for preparing a liquid wax modified polyacrylic acid wood paint, comprising the following steps: S1, weighing raw materials by weight, adding 33 parts of core layer monomer, 0.3 parts of emulsifier and polymerization initiator aqueous solution into reactor 1 at room temperature, wherein the polymerization initiator aqueous solution is prepared by mixing 0.06 parts of polymerization initiator and 8.5 parts of deionized water, and stirring at a stirring speed of 1200 rpm for 25 minutes to obtain a core layer monomer pre-emulsion; At room temperature, 27.95 parts of shell monomer and 0.22 parts of emulsifier were added to a reaction kettle 2 containing 7.8 parts of deionized water, and stirred at a stirring speed of 1200 rpm for 25 minutes to obtain a shell monomer pre-emulsion; S2. At room temperature, in a four-necked flask reactor 3 equipped with a condenser, a thermometer, a stirring paddle and a constant pressure dropping funnel, 0.07 parts of a polymerization initiator, 0.18 parts of an emulsifier and 30 parts of deionized water were added, the rotation speed was adjusted to 600 rpm, and stirred for 1 hour; then the temperature was raised to 80°C, the rotation speed was reduced to 400 rpm, and 3.25 parts of the core layer monomer were uniformly added dropwise to the reactor 3 within 20 minutes, and the reaction was carried out for 1 hour. When the emulsion showed blue light, the seed emulsion was obtained; S3, at a temperature of 80°C and a rotation speed of 600 rpm, within 2 hours, the core layer monomer pre-emulsion in reactor 1 is added dropwise to the seed emulsion in reactor 3, and the temperature is kept for 1 hour to form a core layer emulsion; S4, the shell monomer pre-emulsion, the core layer emulsion and the polymerization initiator aqueous solution in the reaction kettle 2 are mixed, kept at 80°C for 2.5h, and then the temperature is lowered to room temperature, 1.5 parts of diacetone acrylamide, 5 parts of modified toughening agent, 3 parts of flame retardant and adipic acid dihydrazide aqueous solution are added, 0.5 parts of organic amine ester are added dropwise to adjust the pH value to 9, and stirred for 30min to obtain liquid wax modified polyacrylic acid wood paint, wherein the polymerization initiator aqueous solution is prepared by mixing 0.05 parts of initiator and 3.7 parts of deionized water, and the adipic acid dihydrazide aqueous solution is prepared by mixing 0.8 parts of adipic acid dihydrazide and 1 part of deionized water; The modified toughening agent is prepared by the following method: Step A1: 5.02 g of maleic anhydride, 50 mL of toluene and 6.49 g of 3-chloroaniline were mixed, stirred for reaction for 30 min, 10 mL of tetrahydrofuran was added, and stirring was continued for 5 min in an ice-water bath, and 4.58 g of triethylamine was added, and the mixture was reacted for 10 min. The mixture was washed, dried, filtered, and rotary evaporated to obtain a compound; Step A2: 17.93 g of 3-aminopropyltrimethoxysilane and 200 mL of ethanol were mixed and stirred for 30 min, and then 12 g of the compound, 20 mL of acetone and 1 g of triethylamine were added and mixed, and the mixture was stirred at room temperature for 2-3 h, and then rotary evaporated, washed and dried to obtain an intermediate product; Step A3: 0.04 mol of the intermediate product and 150 mL of an ethanol-water mixed solution were mixed at 35° C. for 10 min, 40 mL of toluene and 15 g of toluene diisocyanate were added under nitrogen protection, mixed evenly, and reacted at 80° C. for 2 h to obtain a modified toughening agent, wherein the volume ratio of ethanol to water in the ethanol-water mixed solution was 4:1; The flame retardant is prepared by the following method: Step B1: Add 11.4 g of phenylphosphonic acid and 10.1 g of anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, heat to 110°C for reaction for 1 h, continue to heat to 150°C for reaction for 8 h, evacuate for 0.5 h, cool, add 65 mL of acetone, wash, filter and vacuum dry to obtain a piperazine derivative; Step B2: 0.08 mol of 3-butylenetriethoxysilane and 200 mL of ethanol were mixed, stirred at 80° C. for 10 h, and then 0.08 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added, stirred for 12 h, cooled to room temperature, filtered, and washed to obtain a pre-product; Step B3: After mixing 0.06 mol of the pre-product and 150 mL of an ethanol-water mixed solution at 35 ° C for 10 min, 0.03 mol of a piperazine derivative was added, and the mixture was reacted at 100 ° C for 5 h. The temperature was then adjusted to 25 ° C, and 7.5 g of triethylamine, 80 g of toluene and 20.3 g of diphenylphosphine chloride were added dropwise. After the addition was completed, the temperature was slowly raised to 90 ° C, and the mixture was kept warm for 3 h. The mixture was cooled and dried to obtain a flame retardant. The volume ratio of ethanol to water in the ethanol-water mixed solution was 4:1.

[0016] Comparative Example 1: This comparative example is a liquid wax-modified polyacrylic acid wood paint. The difference from Example 1 is that no Fischer-Tropsch wax solution is added in the preparation of the seed emulsion, and the rest is the same.

[0017] Comparative Example 2: This comparative example is a liquid wax modified polyacrylic acid wood paint. The difference from Example 2 is that no styrene is added to the shell monomer, and the rest is the same.

[0018] Comparative Example 3: This comparative example is a liquid wax modified polyacrylic acid wood paint. The difference from Example 3 is that an equal amount of polybutadiene is used to replace the modified toughening agent prepared in Example 3, and the rest are the same.

[0019] Comparative Example 4: This comparative example is a liquid wax modified polyacrylic acid wood paint. The difference from Example 3 is that an equal amount of magnesium hydroxide is used to replace the flame retardant prepared in Example 3, and the rest are the same.

[0020] Performance test: The liquid wax modified polyacrylic acid wood paint prepared in Examples 1-3 and Comparative Examples 1-2 was prepared into a standard test size. Gel rate: When collecting the material, it was filtered with a 150-mesh gauze, and the filter residue was washed with deionized water and dried in an oven to constant weight. The mass was weighed and recorded as A1. The amount of monomer used during polymerization was A2, and the gel rate was calculated as A1 / A2; Water absorption rate: Pour the emulsion onto the polytetrafluoroethylene template to form a uniform film. Weigh the prepared film sample m1. After soaking it in deionized water at room temperature for 180 hours, use filter paper to absorb the surface moisture and then weigh it m2. The water absorption rate is calculated as (m2-m1) / m1. Cross-linking degree: a 20mm×20mm×2mm film dried to a constant weight of m3 is placed in acetone and soaked for 48 hours, and the acetone solvent is replaced every 8 hours. After two days, the film is taken out and dried at 60°C to a constant weight, and weighed to m4. The cross-linking degree is calculated as m4 / m3; Particle size of emulsion: The surface particle size distribution was tested by Truth Optics LT3600 laser particle size analyzer.

[0021] Determination of coating film hardness: Test the coating film hardness according to GB / T1730-93; Emulsion film-forming temperature: The MFT low-temperature film-forming temperature tester of Jingqiang (Tianjin) Testing Instrument Technology Co., Ltd. was used to test the minimum film-forming temperature of the emulsion; the test results are shown in Table 1 below: Table 1 From the test data in Table 1, it can be seen that, based on the above test data, the control examples 1-2 lack the participation of the Fischer-Tropsch wax solution and styrene in the reaction, and the prepared emulsions have poor water resistance, hardness and crosslinking degree. The average particle size of the embodiments 1-3 of the present invention is 170nm, the average gel fraction is about 0.46%, and the average data of the comprehensive performance is excellent.

[0022] Performance test: The liquid wax modified polyacrylic acid wood paint prepared in Examples 1-3 and Comparative Examples 3-4 was made into a standard test size, and the tensile strength was tested using the standard GB / T 1040.1-2006, the bending test was performed using GB1042-1979, and the combustion performance was tested using GB / T31293-2014; the test results are shown in the following table: Table 2 It can be seen from the test data in Table 2 that the liquid wax modified polyacrylic acid wood paint prepared in the present invention has excellent heat resistance and flame retardant effects. It can also be seen from the above table that the liquid wax modified polyacrylic acid wood paint prepared in the present invention has good tensile strength and bending strength.

[0023] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a liquid wax modified polyacrylic acid wood paint, characterized in that: The specific steps include: S1, weighing the raw materials by weight, mixing 28.4-33.65 parts of core layer monomer, 0.2-0.3 parts of emulsifier and polymerization initiator aqueous solution to obtain core layer monomer pre-emulsion; mixing 21.81-27.95 parts of shell layer monomer, 0.1-0.17 parts of emulsifier and 6-7 parts of deionized water to obtain shell layer monomer pre-emulsion; S2, 0.02-0.05 parts of polymerization initiator, 0.16-0.2 parts of emulsifier and 25.7-28 parts of deionized water, stirred for 0.5-1h, heated to 75-80°C, and then added 1.5-2.6 parts of core layer monomer, reacted for 0.5-1h, to obtain a seed emulsion; S3, mixing the core layer monomer pre-emulsion and the seed emulsion, and keeping the mixture at 75-80° C. for 0.5-1 h to form a core layer emulsion; S4, mixing the shell monomer pre-emulsion, the core layer emulsion and the polymerization initiator aqueous solution, keeping the temperature at 70-85°C for 1.5-2.5h, then lowering the temperature to room temperature, adding 0.3-1.5 parts of diacetone acrylamide, 1-5 parts of modified toughening agent, 1-3 parts of flame retardant and adipic acid dihydrazide aqueous solution, and dropping 0.5 parts of organic amine ester to adjust the pH value to 7-9, to obtain liquid wax modified polyacrylic acid wood paint; The adipic acid dihydrazide aqueous solution is prepared by mixing 0.3-0.8 parts by weight of adipic acid dihydrazide and 2-3 parts by weight of deionized water; The modified toughening agent is prepared by the following method: Step A1: maleic anhydride, toluene and 3-chloroaniline were mixed, stirred for reaction for 30 minutes, tetrahydrofuran was added, and stirring was continued for 5 minutes in an ice-water bath, and triethylamine was added, and the mixture was reacted for 10 minutes, washed, dried, filtered, and rotary evaporated to obtain a compound; Step A2: 3-aminopropyltrimethoxysilane and ethanol were mixed and stirred for 30 minutes, and then the compound, acetone and triethylamine were added and mixed, and the mixture was stirred at room temperature for 2-3 hours, and then rotary evaporated, washed and dried to obtain an intermediate product; Step A3: The intermediate product and the ethanol-water mixed solution were mixed at 35° C. for 10 min, toluene and toluene diisocyanate were added under nitrogen protection and mixed evenly, and the mixture was reacted at 80° C. for 2 h to obtain a modified toughening agent.

2. The method for preparing a liquid wax modified polyacrylic acid wood paint according to claim 1, characterized in that: The polymerization initiator aqueous solution in step S1 is prepared by mixing 0.03-0.08 parts of polymerization initiator with 6-7 parts of deionized water.

3. The method for preparing a liquid wax modified polyacrylic acid wood paint according to claim 1, characterized in that: The polymerization initiator aqueous solution in step S4 is prepared by mixing 0.01-0.05 parts of initiator and 4-6 parts of deionized water.

4. The method for preparing a liquid wax modified polyacrylic acid wood paint according to claim 1, characterized in that: In step A1, the usage ratio of maleic anhydride, toluene, 3-chloroaniline, tetrahydrofuran and triethylamine is 4.81-5.02 g:40-50 mL:6.28-6.49 g:10 mL:3.11-4.58 g.

5. The method for preparing a liquid wax modified polyacrylic acid wood paint according to claim 1, characterized in that: In step A2, the usage ratio of 3-aminopropyltrimethoxysilane, ethanol, compound, acetone and triethylamine is 8.95-17.93 g: 200 mL: 10-12 g: 20 mL: 0.5-1 g.

6. The method for preparing a liquid wax modified polyacrylic acid wood paint according to claim 1, characterized in that: The usage ratio of the intermediate product, ethanol-water mixed solution, toluene and toluene diisocyanate in step A3 is 0.02-0.04 mol:150 mL:20-40 mL:7.5-15 g, and the volume ratio of ethanol to water in the ethanol-water mixed solution is 4:

1.

7. The method for preparing a liquid wax modified polyacrylic acid wood paint according to claim 1, characterized in that: The flame retardant is prepared by the following method: Step B1: Add phenylphosphonic acid and anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, and heat to 110°C for reaction for 1 hour. Continue to heat to 150°C for reaction for 8 hours, evacuate for 0.5 hours, cool, add acetone, wash, filter, and vacuum dry to obtain a piperazine derivative. The dosage ratio of phenylphosphonic acid, anhydrous piperazine, and acetone is 7.6-11.4 g: 8.5-10.1 g: 45-65 mL. Step B2: 3-Butenetriethoxysilane and ethanol are mixed, stirred at 80°C for 10 hours, and then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added, stirred for 12 hours, cooled to room temperature, filtered, and washed to obtain a pre-product, wherein the amount ratio of 3-Butenetriethoxysilane, ethanol, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 0.05-0.08 mol: 200 mL: 0.05-0.08 mol; Step B3: After mixing the pre-product and the ethanol-water mixed solution at 35°C for 10 minutes, add the piperazine derivative, react at 100°C for 5 hours, then adjust the temperature to 25°C, drop triethylamine, toluene and diphenylphosphine chloride and mix, slowly heat to 90°C after the addition, keep the temperature for reaction for 3 hours, cool and dry to obtain a flame retardant, the amount ratio of the pre-product, ethanol-water mixed solution, piperazine derivative, triethylamine, toluene and diphenylphosphine chloride is 0.04-0.06mol: 150mL: 0.02-0.03mol: 7.5g: 50-80g: 13.5-20.3g, and the volume ratio of ethanol to water in the ethanol-water mixed solution is 4:

1.

8. The method for preparing a liquid wax modified polyacrylic acid wood paint according to claim 1, characterized in that: The diacetone acrylamide and adipic acid dihydrazide are emulsion polymerization cross-linking reagents, the polymerization initiator is potassium persulfate, the emulsifier is nonylphenol polyoxyethylene ether, and the organic amine ester is a neutralizer.

9. The method for preparing a liquid wax modified polyacrylic acid wood paint according to claim 1, characterized in that: The core layer monomer is a mixture of 8-10 parts of methyl methacrylate, 7-9 parts of butyl acrylate, 0.2-0.25 parts of methacrylic acid, 7 parts of N-hydroxymethyl acrylamide, and 7.7-10 parts of Fischer-Tropsch wax solution; the shell layer monomer is a mixture of 8-10 parts of methyl methacrylate, 7-9 parts of butyl acrylate, 0.2-0.25 parts of methacrylic acid, 7.5-8 parts of 2-hydroxyethyl methacrylate, and 8-10 parts of styrene.

10. A liquid wax modified polyacrylic acid wood paint, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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