Flame-retardant acrylate emulsion for water-based paint and preparation method of flame-retardant acrylate emulsion

Abstract

The invention relates to the technical field of water-based coatings, in particular to a flame-retardant acrylate emulsion for a water-based coating, a preparation method of the flame-retardant acrylate emulsion and a water-based flame-retardant coating prepared from the flame-retardant acrylate emulsion. The preparation method comprises the following steps: firstly preparing a phosphorus-containing acrylate monomer and a urea-containing acrylate monomer, then copolymerizing the phosphorus-containing acrylate monomer and the urea-containing acrylate monomer with other acrylate monomers by adopting an in-situ polymerization method to obtain the acrylate emulsion for the water-based paint with excellent flame-retardant property, and adding the acrylate emulsion into a paint formula to obtain the flame-retardant water-based paint. The prepared water-based flame-retardant coating has excellent flame retardance and impact resistance.

Description

Technical Field

[0001] The invention relates to the technical field of water-based coatings, and in particular to a flame-retardant acrylic emulsion for water-based coatings and a preparation method thereof. Background Art

[0002] Waterborne coatings, also known as water-based paints or water-based paints, are types of coatings that use water as the main solvent. Because they avoid or reduce the use of solvents and reduce VOC emissions, they are green and environmentally friendly coatings. Waterborne coatings include water-dispersible, water-dilutable and water-soluble types. In the global coatings market, the total output value of waterborne coatings accounts for more than 50%, and the output accounts for more than 60%, and the market is still growing.

[0003] Waterborne coatings can be divided into four types according to the different waterborne resins used to synthesize the coatings: acrylic coatings, acetic acid coatings, epoxy coatings, and polyurethane coatings. Among them, waterborne acrylic resin coatings are the main varieties, which have the characteristics of light resistance, weather resistance, heat resistance, etc., and are light in color, good leveling, and good construction performance. They have been widely used in the automotive, building materials, home furnishing and other industries. Although waterborne acrylic coatings have many advantages, they also have disadvantages such as long drying time, easy to become sticky at high temperatures, easy to become brittle at low temperatures, and flammable.

[0004] For the flame retardant modification of waterborne acrylic coatings, the method of adding flame retardants is usually used. The types of flame retardants include halogen flame retardants, filled flame retardants and intumescent flame retardants. Halogen flame retardants are a type of flame retardants that contain halogen elements and use halogen elements to play a flame retardant role. The flame retardant mechanism includes blocking cooling, terminating chain reactions, and cutting off heat sources. However, since halogen flame retardants are prone to produce harmful substances such as dioxins during the flame retardant process, their use is restricted. Filled flame retardants include magnesium hydroxide, aluminum hydroxide, etc., which release bound water during combustion and heat decomposition and absorb a large amount of latent heat to reduce the temperature of the filled material in the flame, thereby playing a flame retardant effect. Intumescent flame retardants are also called nitrogen-phosphorus flame retardants. They use phosphorus and nitrogen as the main flame retardant components. They are a new type of halogen-free environmentally friendly flame retardant that integrates carbon source, acid source and gas source. When heated, this type of flame retardant can produce a synergistic flame retardant effect of phosphorus-nitrogen in the molecule. When burning, it will form a layer of carbon foam on the surface of the plastic, thereby achieving the effects of heat insulation, oxygen isolation, smoke suppression, and drip prevention.

[0005] In-situ flame retardant modification is a flame retardant modification method developed in recent years. This method is different from the previous method of adding flame retardants. Instead, it embeds flame retardant matrices such as phosphorus and nitrogen into acrylate monomers and in-situ polymerizes them to form acrylate polymers. It is significantly superior to the previous flame retardant method of adding flame retardants in terms of flame retardancy and durability. Summary of the invention

[0006] In order to solve the above technical problems, the present invention, based on previous research, first prepares phosphorus-containing acrylate monomers and urea-containing acrylate monomers, and then, in-situ polymerization is used to copolymerize them with other acrylate monomers to obtain an acrylate emulsion for water-based coatings with excellent flame retardancy, which is added to the coating formula to obtain a water-based flame-retardant coating with excellent flame retardancy and impact resistance. The present invention also studies the influence of the polymerization method on the flame retardancy, and through research, it is proved that the core-shell structured acrylate emulsion obtained by using the seed emulsion synthesis method and the phosphorus-containing acrylate monomer and the urea-containing acrylate monomer as the shell raw materials can further improve the flame retardancy of the acrylate emulsion.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A flame-retardant acrylic emulsion for water-based coatings, comprising the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10-20 parts of ethyl acrylate, 5-10 parts of isooctyl acrylate, 5-8 parts of hydroxyethyl acrylate, 8-12 parts of phosphorus-containing acrylic acid ester monomers, 4-10 parts of urea-containing acrylic acid ester monomers, 4-7 parts of initiators, 3-6 parts of emulsifiers, and 50-80 parts of deionized water; The emulsifier includes 1-3 parts of fatty alcohol polyoxyethylene ether and 2-3 parts of sodium lauryl sulfate; The initiator includes one or a combination of two or more of ammonium persulfate, sodium persulfate and potassium persulfate.

[0008] The preparation method of the phosphorus-containing acrylate monomer is as follows: Phosphorus oxychloride and hydroxyethyl acrylate are added to a stirring device, and then an appropriate amount of toluene is added, nitrogen is introduced to expel the air, the system temperature is lowered to 0°C, stirred for reaction for 2-3 hours, and then the temperature is raised to room temperature for reaction for 10-12 hours. The solution is dried using a rotary evaporator to obtain a phosphorus-containing acrylate monomer.

[0009] The reaction equation of the phosphorus oxychloride and hydroxyethyl acrylate is as follows:

[0010] The molar ratio of phosphorus oxychloride to hydroxyethyl acrylate is 1:3.

[0011] The preparation method of the urea-containing acrylate monomer is as follows: Add p-trifluoromethylaniline and ethyl 2-isocyanate acrylate to a stirring device, then add an appropriate amount of tetrahydrofuran to dissolve, introduce nitrogen, lower the system temperature to 0°C, stir and react for 4-6 hours, then heat to room temperature and react for 10-12 hours, use a rotary evaporator to spin dry the solution to obtain a urea-containing acrylate monomer.

[0012] The reaction equation of trifluoromethylaniline and 2-isocyanate ethyl acrylate is as follows:

[0013] The molar ratio of p-trifluoromethylaniline to 2-ethyl isocyanate acrylate is 1:1.

[0014] The usage ratio of the phosphorus-containing acrylate monomer to the urea-containing acrylate monomer is 3:1-2.

[0015] The method for preparing the flame-retardant acrylic emulsion for water-based coatings comprises the following steps: (1) Preparation of seed emulsion: Add 1-3 parts of fatty alcohol polyoxyethylene ether, 2-3 parts of sodium lauryl sulfate, and 50-80 parts of deionized water into a reactor, stir to dissolve, add 3-5 parts of initiator, raise the temperature to 60-80°C, and then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10-20 parts of ethyl acrylate, 5-10 parts of isooctyl acrylate, and 5-8 parts of hydroxyethyl acrylate. The dropwise addition time is 1-2 hours. After the dropwise addition is completed, keep the temperature for reaction for 1-2 hours.

[0016] (2) Preparation of core-shell emulsion: Add a mixed solution containing 1-2 parts of initiator, 8-12 parts of phosphorus acrylate monomer and 4-10 parts of urea-containing acrylate monomer to the above seed emulsion for 1-2 hours. After the addition is completed, keep warm for 2-3 hours at a reaction temperature of 60-80°C to obtain a core-shell structure emulsion. Add ammonia water to the emulsion prepared above, adjust the pH value to 7-10, and filter the material to obtain a flame-retardant acrylate emulsion for water-based coatings.

[0017] Furthermore, the initiators in step (1) and step (2) are of the same type.

[0018] Another object of the present invention is to provide a water-based coating prepared using the flame-retardant acrylic emulsion, wherein the water-based coating comprises the following components in parts by weight: 100 parts of the flame-retardant acrylic emulsion, 10-20 parts of a pigment, 10-30 parts of a filler, 1-3 parts of a dispersant, 2-5 parts of a thickener, and 2-5 parts of a defoaming agent.

[0019] The preparation process of the water-based coating is as follows: By weight, 100 parts of flame retardant acrylic emulsion, 10-20 parts of pigment, 10-30 parts of filler, 1-3 parts of dispersant, 2-5 parts of thickener and 2-5 parts of defoamer are mixed to prepare a flame retardant acrylic coating.

[0020] The pigment is one or a combination of titanium dioxide, iron oxide red, iron oxide yellow, carbon black, ultramarine, lead chrome yellow, phthalocyanine blue, and phthalocyanine green; The filler is one or a combination of calcium carbonate, talcum powder, mica powder, kaolin, quartz sand, and barium sulfate; The dispersant is a combination of one or more of Disponer W-511, W-920, and Dispex AA4140.

[0021] The thickener is one of TEGO3000 and TEGO3030 or a combination of the two; The defoaming agent is a combination of one or more of DefomW-082, XP-502E, and BYK-024.

[0022] Based on actual needs, the present invention may also add auxiliary agents commonly used in the art, such as cross-linking agents, wetting agents, antioxidants, film-forming agents, solvents, and the like.

[0023] The crosslinking agent may be any crosslinking agent commonly used in the art, such as polyisocyanate, epoxy, aziridine, etc. Since the synthetic raw materials of the flame-retardant acrylate emulsion of the present application contain phosphorus-containing acrylate monomers with branched structures, the use of the crosslinking agent may be omitted as appropriate.

[0024] The wetting agent may be anionic wetting agent, cationic wetting agent, nonionic wetting agent, etc., and the anionic wetting agent includes sulfate ester salts, sulfonates, phosphate ester salts, etc.; The cationic wetting agents mainly include quaternary ammonium salts, amine salts, etc. The nonionic wetting agents mainly include polyoxyethylene ethers, polyoxyethylene esters, polyoxyethylene amines and the like.

[0025] The antioxidants include phosphate antioxidants, hindered phenol antioxidants and the like.

[0026] The film formers include alcohols, alcohol esters, alcohol ethers, alcohol ether esters and the like.

[0027] The solvent includes toluene, ethanol, propylene glycol methyl ether, dipropylene glycol butyl ether and the like.

[0028] The above-mentioned additives can be used in appropriate amounts as long as they do not affect the normal properties of water-based coatings.

[0029] Compared with the prior art, the present invention has the following beneficial effects: The flame-retardant acrylic emulsion of the present invention utilizes phosphorus oxychloride and hydroxyethyl acrylate to react according to a molar ratio of 1:3 to obtain a phosphorus-containing acrylic monomer containing a branched structure, and the monomer has a branched structure, which can improve the crosslinking degree of the synthesized acrylic emulsion, and then improve its mechanical properties. In addition, the present invention adopts trifluoromethylaniline and 2-isocyanate ethyl acrylate to react in a molar ratio of 1:1 to obtain a urea-containing acrylic monomer, which has a high nitrogen content and is compounded with the synthesized phosphorus-containing acrylic monomer to form a nitrogen-phosphorus flame retardant system, which enhances the carbonization of the acrylic film during combustion, reduces the contact of internal materials with oxygen, and inhibits combustion. The present invention adopts a synthetic process of preparing a seed emulsion first and then preparing a core-shell structure acrylic ester, and the outer part of the core-shell structure acrylic emulsion particles formed by the phosphorus-containing acrylic monomer and the urea-containing acrylic monomer further improves the flame retardancy of the synthesized acrylic emulsion, and the urea-containing acrylic monomer also includes a fluorine group, which can further improve the waterproofness of the acrylic emulsion. DETAILED DESCRIPTION

[0030] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0031] Synthesis example 1 Preparation of phosphorus-containing acrylate monomers: 15.3 g (0.1 mol) of phosphorus oxychloride and 34.8 g (0.3 mol) of hydroxyethyl acrylate were added to a four-necked flask with a stirring device, and then 300 ml of toluene was added. Nitrogen was introduced to expel the air, and the system temperature was lowered to 0°C using an ice bath. The reaction was stirred for 2.5 hours, and then the temperature was raised to room temperature for 12 hours. The solution was dried using a rotary evaporator to obtain a phosphorus-containing acrylate monomer, which was recorded as P1.

[0032] Synthesis example 2 Preparation of urea-containing acrylate monomers: 16.1 g (0.1 mol) of p-trifluoromethylaniline and 14.1 g (0.1 mol) of ethyl 2-isocyanate acrylate were added to a four-necked flask with a stirring device, and then 300 ml of tetrahydrofuran was added to dissolve. Nitrogen was introduced, and the system temperature was lowered to 0°C with an ice bath. The reaction was stirred for 5 hours, and then the temperature was raised to room temperature for 12 hours. The solution was dried using a rotary evaporator to obtain a urea-containing acrylate monomer, which was recorded as P2.

[0033] Example 1 A flame-retardant acrylic emulsion for water-based coatings, comprising the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 9 parts of phosphorus-containing acrylic acid ester monomer P1, 6 parts of urea-containing acrylic acid ester monomer P2, 4 parts of ammonium persulfate, 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water; The preparation process of the flame-retardant acrylic emulsion for water-based coating is as follows: (1) Preparation of seed emulsion: Add 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water into a reactor, stir and dissolve, then add 3 parts of ammonium persulfate, raise the temperature to 65°C, and then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate and 6 parts of hydroxyethyl acrylate. The dropwise addition time is 1.5 hours. After the dropwise addition is completed, keep the temperature for reaction for 2 hours.

[0034] (2) Preparation of core-shell emulsion: A mixed solution containing 1 part of ammonium persulfate, 9 parts of phosphorus-containing acrylate monomer P1 and 6 parts of urea-containing acrylate monomer P2 was added dropwise to the above seed emulsion for 1 hour. After the addition was completed, the mixture was kept warm for 2.5 hours at a reaction temperature of 70°C to obtain a core-shell structure emulsion. Ammonia water was added to the emulsion prepared above, the pH value was adjusted to 8, and the material was filtered to obtain a flame-retardant acrylate emulsion for water-based coatings.

[0035] Example 2 A flame-retardant acrylic emulsion for water-based coatings, composed of the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 12 parts of phosphorus-containing acrylic acid ester monomer P1, 4 parts of urea-containing acrylic acid ester monomer P2, 4 parts of ammonium persulfate, 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water; The preparation process of the flame-retardant acrylic emulsion for water-based coating is as follows: (1) Preparation of seed emulsion: Add 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water into a reactor, stir and dissolve, then add 3 parts of ammonium persulfate, raise the temperature to 65°C, and then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate and 6 parts of hydroxyethyl acrylate. The dropwise addition time is 1.5 hours. After the dropwise addition is completed, keep the temperature for reaction for 2 hours.

[0036] (2) Preparation of core-shell emulsion: A mixed solution containing 1 part of ammonium persulfate, 12 parts of phosphorus-containing acrylate monomer P1 and 4 parts of urea-containing acrylate monomer P2 was added dropwise to the above seed emulsion for 1 hour. After the addition was completed, the mixture was kept warm for 2.5 hours at a reaction temperature of 70°C to obtain a core-shell structure emulsion. Ammonia water was added to the emulsion prepared above, the pH value was adjusted to 8, and the material was filtered to obtain a flame-retardant acrylate emulsion for water-based coatings.

[0037] Example 3 A flame-retardant acrylic emulsion for water-based coatings, composed of the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 12 parts of phosphorus-containing acrylic monomer P1, 8 parts of urea-containing acrylic monomer P2, 4 parts of ammonium persulfate, 1 part of fatty alcohol polyoxyethylene ether, 3 parts of sodium lauryl sulfate and 70 parts of deionized water; The preparation process of the flame-retardant acrylic emulsion for water-based coating is as follows: (1) Preparation of seed emulsion: Add 1 part of fatty alcohol polyoxyethylene ether, 3 parts of sodium lauryl sulfate and 70 parts of deionized water into a reactor, stir and dissolve, then add 3 parts of ammonium persulfate, raise the temperature to 70°C, and then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate and 6 parts of hydroxyethyl acrylate. The dropwise addition time is 1.5 hours. After the dropwise addition is completed, keep the temperature for reaction for 2 hours.

[0038] (2) Preparation of core-shell emulsion: A mixed solution containing 1 part of ammonium persulfate, 12 parts of phosphorus-containing acrylate monomer P1 and 8 parts of urea-containing acrylate monomer P2 was added dropwise to the above seed emulsion for 1 hour. After the addition was completed, the mixture was kept warm for 2.5 hours at a reaction temperature of 75°C to obtain a core-shell structure emulsion. Ammonia water was added to the emulsion prepared above, the pH value was adjusted to 8, and the material was filtered to obtain a flame-retardant acrylate emulsion for water-based coatings.

[0039] Comparative Example 1 A flame-retardant acrylic emulsion for water-based coatings, composed of the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 15 parts of phosphorus-containing acrylic monomer P1, 4 parts of ammonium persulfate, 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water; The preparation process of the flame-retardant acrylic emulsion for water-based coating is as follows: (1) Preparation of seed emulsion: Add 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water into a reactor, stir and dissolve, then add 3 parts of ammonium persulfate, raise the temperature to 65°C, and then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate and 6 parts of hydroxyethyl acrylate. The dropwise addition time is 1.5 hours. After the dropwise addition is completed, keep the temperature for reaction for 2 hours.

[0040] (2) Preparation of core-shell emulsion: A mixed solution containing 1 part of ammonium persulfate and 15 parts of phosphorus-containing acrylate monomer P1 was added dropwise to the above seed emulsion for 1 hour. After the addition was completed, the mixture was kept warm for 2.5 hours at a reaction temperature of 70°C to obtain a core-shell structure emulsion. Ammonia water was added to the emulsion prepared above, the pH value was adjusted to 8, and the material was filtered to obtain a flame-retardant acrylate emulsion for water-based coatings.

[0041] Comparative Example 2 A flame-retardant acrylic emulsion for water-based coatings, comprising the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 15 parts of urea-containing acrylic acid ester monomer P2, 4 parts of ammonium persulfate, 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water; The preparation process of the flame-retardant acrylic emulsion for water-based coating is as follows: (1) Preparation of seed emulsion: Add 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water into a reactor, stir and dissolve, then add 3 parts of ammonium persulfate, raise the temperature to 65°C, and then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate and 6 parts of hydroxyethyl acrylate. The dropwise addition time is 1.5 hours. After the dropwise addition is completed, keep the temperature for reaction for 2 hours.

[0042] (2) Preparation of core-shell emulsion: A mixed solution containing 1 part of ammonium persulfate and 15 parts of urea-containing acrylate monomer P2 was added dropwise to the above seed emulsion for 1 hour. After the addition was completed, the mixture was kept warm for 2.5 hours at a reaction temperature of 70°C to obtain a core-shell structure emulsion. Ammonia water was added to the emulsion prepared above, the pH value was adjusted to 8, and the material was filtered to obtain a flame-retardant acrylate emulsion for water-based coatings.

[0043] Comparative Example 3 A flame-retardant acrylic emulsion for water-based coatings, composed of the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 12 parts of phosphorus-containing acrylic acid ester monomer P1, 3 parts of urea-containing acrylic acid ester monomer P2, 4 parts of ammonium persulfate, 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water; The preparation process of the flame-retardant acrylic emulsion for water-based coating is as follows: (1) Preparation of seed emulsion: Add 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water into a reactor, stir and dissolve, then add 3 parts of ammonium persulfate, raise the temperature to 65°C, and then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate and 6 parts of hydroxyethyl acrylate. The dropwise addition time is 1.5 hours. After the dropwise addition is completed, keep the temperature for reaction for 2 hours.

[0044] (2) Preparation of core-shell emulsion: A mixed solution containing 1 part of ammonium persulfate, 12 parts of phosphorus-containing acrylate monomer P1 and 3 parts of urea-containing acrylate monomer P2 was added dropwise to the above seed emulsion for 1 hour. After the addition was completed, the mixture was kept warm for 2.5 hours at a reaction temperature of 70°C to obtain a core-shell structure emulsion. Ammonia water was added to the emulsion prepared above, the pH value was adjusted to 8, and the material was filtered to obtain a flame-retardant acrylate emulsion for water-based coatings.

[0045] Comparative Example 4 A flame-retardant acrylic emulsion for water-based coatings, composed of the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 8 parts of phosphorus-containing acrylic acid ester monomer P1, 8 parts of urea-containing acrylic acid ester monomer P2, 4 parts of ammonium persulfate, 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water; The preparation process of the flame retardant acrylic emulsion for coating is as follows: (1) Preparation of seed emulsion: Add 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water into a reactor, stir and dissolve, then add 3 parts of ammonium persulfate, raise the temperature to 65°C, and then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate and 6 parts of hydroxyethyl acrylate. The dropwise addition time is 1.5 hours. After the dropwise addition is completed, keep the temperature for reaction for 2 hours.

[0046] (2) Preparation of core-shell emulsion: A mixed solution containing 1 part of ammonium persulfate, 8 parts of phosphorus-containing acrylate monomer P1 and 8 parts of urea-containing acrylate monomer P2 was added dropwise to the above seed emulsion for 1 hour. After the addition was completed, the mixture was kept warm for 2.5 hours at a reaction temperature of 70°C to obtain a core-shell structure emulsion. Ammonia water was added to the emulsion prepared above, the pH value was adjusted to 8, and the material was filtered to obtain a flame-retardant acrylate emulsion for water-based coatings.

[0047] Comparative Example 5 A flame-retardant acrylic emulsion for water-based coatings, comprising the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 9 parts of phosphorus-containing acrylic acid ester monomer P1, 6 parts of urea-containing acrylic acid ester monomer P2, 4 parts of ammonium persulfate, 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate and 60 parts of deionized water; The preparation process of the flame-retardant acrylic emulsion for water-based coating is as follows: Add 2 parts of fatty alcohol polyoxyethylene ether, 2 parts of sodium lauryl sulfate, and 60 parts of deionized water to the reactor, stir and dissolve, add 4 parts of ammonium persulfate, heat to 65°C, then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10 parts of ethyl acrylate, 8 parts of isooctyl acrylate, 6 parts of hydroxyethyl acrylate, 9 parts of phosphorus-containing acrylate monomer P1 and 6 parts of urea-containing acrylate monomer P2, the drop time is 1.5h, and after the drop is complete, keep warm for reaction, the reaction time is 2h. Add ammonia water to the prepared emulsion, adjust the pH value to 8, filter the material, and obtain a flame-retardant acrylate emulsion for water-based coatings.

[0048] Application Example 1 By weight, 100 parts of the flame-retardant acrylic emulsion obtained in Example 1, 15 parts of titanium dioxide, 18 parts of calcium carbonate, 2 parts of Disponer W-511, 3 parts of TEGO 3000, and 2 parts of Defom W-082 were mixed to prepare a water-based flame-retardant acrylic coating S1.

[0049] Application Example 2 By weight, 100 parts of the flame-retardant acrylic emulsion obtained in Example 2, 15 parts of titanium dioxide, 18 parts of calcium carbonate, 2 parts of Disponer W-511, 3 parts of TEGO 3000, and 2 parts of Defom W-082 were mixed to prepare a water-based flame-retardant acrylic coating S2.

[0050] Application Example 3 By weight, 100 parts of the flame-retardant acrylic emulsion obtained in Example 3, 15 parts of titanium dioxide, 18 parts of calcium carbonate, 2 parts of Disponer W-511, 3 parts of TEGO 3000, and 2 parts of Defom W-082 were mixed to prepare a water-based flame-retardant acrylic coating S3.

[0051] Comparative Application Example 1 By weight, 100 parts of the flame-retardant acrylic emulsion obtained in Comparative Example 1, 15 parts of titanium dioxide, 18 parts of calcium carbonate, 2 parts of Disponer W-511, 3 parts of TEGO 3000, and 2 parts of Defom W-082 were mixed to prepare a water-based flame-retardant acrylic coating W1.

[0052] Comparative Application Example 2 By weight, 100 parts of the flame-retardant acrylic emulsion obtained in Comparative Example 2, 15 parts of titanium dioxide, 18 parts of calcium carbonate, 2 parts of Disponer W-511, 3 parts of TEGO 3000, and 2 parts of Defom W-082 were mixed to prepare a water-based flame-retardant acrylic coating W2.

[0053] Comparative Application Example 3 By weight, 100 parts of the flame-retardant acrylic emulsion obtained in Comparative Example 3, 15 parts of titanium dioxide, 18 parts of calcium carbonate, 2 parts of Disponer W-511, 3 parts of TEGO 3000, and 2 parts of Defom W-082 were mixed to prepare a water-based flame-retardant acrylic coating W3.

[0054] Comparative Application Example 4 By weight, 100 parts of the flame-retardant acrylic emulsion obtained in Comparative Example 4, 15 parts of titanium dioxide, 18 parts of calcium carbonate, 2 parts of Disponer W-511, 3 parts of TEGO 3000, and 2 parts of Defom W-082 were mixed to prepare a water-based flame-retardant acrylic coating W4.

[0055] Comparative Application Example 5 By weight, 100 parts of the flame-retardant acrylic emulsion obtained in Comparative Example 5, 15 parts of titanium dioxide, 18 parts of calcium carbonate, 2 parts of Disponer W-511, 3 parts of TEGO 3000, and 2 parts of Defom W-082 were mixed to prepare a water-based flame-retardant acrylic coating W5.

[0056] Performance Testing The obtained water-based flame-retardant acrylic paint was used to prepare the required samples according to the standard. The flame retardant performance of the paint film was tested by an oxygen index tester according to GB / T2406.1-2008. The impact resistance was tested by a paint film impactor according to the GB / T1732-93 method. The hardness was tested by a pencil hardness tester according to the GB / T6739-2022 method.

[0057] Table 1 Test results of water-based flame-retardant acrylic coatings obtained in various application examples and comparative application examples

[0058] By comparing application example S1 with comparative application examples W1-W4, it can be seen that the combination of the phosphorus-containing acrylate monomer synthesized in the present application and the urea-containing acrylate monomer has a significant improvement in flame retardancy, impact resistance and hardness compared to the use of the phosphorus-containing acrylate monomer or the urea-containing acrylate monomer alone. And when the mass ratio of the phosphorus-containing acrylate monomer to the urea-containing acrylate monomer is within a limited range, the flame retardancy, impact resistance and pencil hardness of the obtained coating are optimal.

[0059] By comparing application example S1 with comparative application example W5, it can be seen that the preparation process of the flame-retardant acrylic emulsion of the present application is adopted. The seed emulsion is prepared first, and then the core-shell structure acrylic ester is prepared, and the outer part of the core-shell structure acrylic emulsion particles formed by the phosphorus-containing acrylic ester monomer and the urea-containing acrylic ester monomer is further improved in flame retardancy, impact resistance and hardness of the synthesized acrylic emulsion.

[0060] 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 defined scope, they should all fall within the protection scope of the present invention.

Claims

1. A flame retardant acrylic emulsion for water-based coatings, characterized in that: The invention is composed of the following raw materials in parts by weight: 40 parts of methyl methacrylate, 10-20 parts of ethyl acrylate, 5-10 parts of isooctyl acrylate, 5-8 parts of hydroxyethyl acrylate, 8-12 parts of phosphorus-containing acrylate monomer, 4-10 parts of urea-containing acrylate monomer, 4-7 parts of initiator, 3-6 parts of emulsifier, and 50-80 parts of deionized water, wherein the ratio of the phosphorus-containing acrylate monomer to the urea-containing acrylate monomer is 3:1-2; The preparation method of the urea-containing acrylate monomer is as follows: adding trifluoromethylaniline and ethyl 2-isocyanate acrylate to a stirring device, then adding an appropriate amount of tetrahydrofuran to dissolve, introducing nitrogen, lowering the system temperature to 0°C, stirring for reaction for 4-6 hours, then heating to room temperature for reaction for 10-12 hours, and using a rotary evaporator to spin-dry the solution to obtain the urea-containing acrylate monomer.

2. The flame-retardant acrylic emulsion for water-based coatings according to claim 1, characterized in that: The emulsifier comprises 1-3 parts of fatty alcohol polyoxyethylene ether and 2-3 parts of sodium lauryl sulfate.

3. The flame-retardant acrylic emulsion for water-based coating according to claim 1, characterized in that: The initiator is one or a combination of two or more of ammonium persulfate, sodium persulfate and potassium persulfate.

4. The flame-retardant acrylic emulsion for water-based coatings according to claim 1, characterized in that: The preparation method of the phosphorus-containing acrylate monomer is as follows: phosphorus oxychloride and hydroxyethyl acrylate are added to a stirring device, then an appropriate amount of toluene is added, nitrogen is introduced to exhaust the air, the system temperature is lowered to 0°C, stirred for reaction for 2-3 hours, then the temperature is raised to room temperature for reaction for 10-12 hours, and the solution is dried by a rotary evaporator to obtain the phosphorus-containing acrylate monomer.

5. The flame-retardant acrylic emulsion for water-based coating according to claim 4, characterized in that: The molar ratio of phosphorus oxychloride to hydroxyethyl acrylate is 1:

3.

6. The flame-retardant acrylic emulsion for water-based coating according to claim 1, characterized in that: The molar ratio of p-trifluoromethylaniline to 2-ethyl isocyanate acrylate is 1:

1.

7. A method for preparing a flame-retardant acrylic emulsion for water-based coatings according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Prepare seed emulsion: add 1-3 parts of fatty alcohol polyoxyethylene ether, 2-3 parts of sodium lauryl sulfate, and 50-80 parts of deionized water to a reactor, stir and dissolve, add 3-5 parts of initiator, heat to 60-80°C, then start to drop a mixed liquid consisting of 40 parts of methyl methacrylate, 10-20 parts of ethyl acrylate, 5-10 parts of isooctyl acrylate, and 5-8 parts of hydroxyethyl acrylate, the dropping time is 1-2h, and after the dropping is completed, keep warm for reaction, the reaction time is 1-2h; Step 2: Prepare a core-shell emulsion: add a mixed solution containing 1-2 parts of an initiator, 8-12 parts of a phosphorus-containing acrylate monomer and 4-10 parts of a urea-containing acrylate monomer to the above-mentioned seed emulsion, the addition time is 1-2 hours, and after the addition is completed, the reaction is kept warm for 2-3 hours at a reaction temperature of 60-80°C to obtain a core-shell structure emulsion, add ammonia water to the emulsion prepared above, adjust the pH value to 7-10, filter the material, and obtain a flame-retardant acrylate emulsion for water-based coatings.

8. The method for preparing a flame-retardant acrylic emulsion for water-based coatings according to claim 7, characterized in that: The initiators in step 1 and step 2 are the same type of initiators.

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