Flame-retardant putty powder and preparation method thereof

Abstract

The invention relates to the technical field of building materials, in particular to flame-retardant putty powder and a preparation method thereof.The flame-retardant putty powder is prepared from, by weight, 70-80 parts of heavy calcium carbonate; 20 to 30 parts of ash calcium powder; 0.3 to 0.5 part of cellulose; 0.05 to 1 part of starch ether; and 0.5-2 parts of vinylidene chloride-based copolymer latex powder. According to the flame-retardant putty powder provided by the invention, through the synergistic effect of the vinylidene chloride-based copolymer latex powder and all the components, the performance is remarkably improved. Due to the addition of the vinylidene chloride-based copolymer latex powder, the putty powder provided by the invention has favorable flame retardancy, can achieve excellent water resistance under the condition of not adding a hydrophobic compound or a water repellent, and is simpler in formula, lower in cost and more environment-friendly.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a flame-retardant putty powder and its preparation method. Background Technology

[0002] In recent years, with the vigorous development of the construction industry, building decoration materials have been constantly being innovated. Among them, putty powder is a basic raw material that is widely used in building decoration materials. It is generally used as a base treatment for walls before painting, making the wall surface smoother and flatter, and making the wall surface more beautiful after painting.

[0003] Currently, the main components of ordinary putty powder on the market are gypsum powder, lime powder, calcium carbonate, talc powder, white cement, etc. Most of these putty powders do not have flame retardancy. However, putty powder used in public places such as shopping malls, hotels, schools, hospitals, and office buildings, as well as putty powder used in spaces with special fire protection requirements such as kitchens, garages, and electrical rooms, is required to have a certain degree of flame retardancy.

[0004] Therefore, how to provide a flame-retardant putty powder is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] To address the problem that existing putty powders lack flame retardancy, this invention provides a flame-retardant putty powder. This flame-retardant putty powder, through the synergistic effect of vinylidene chloride copolymer latex powder and its components, exhibits excellent flame retardant properties while maintaining high bonding strength, thus solving the problem of poor flame retardancy in existing putty powders.

[0006] The technical solution adopted by this invention to solve its technical problem is: A flame-retardant putty powder, by weight, comprises the following components: 70-80 parts of heavy calcium carbonate; 20-30 parts of lime powder; 0.3-0.5 parts cellulose; Starch ether 0.05-1 part; Vinylidene chloride copolymer latex powder: 0.5-2 parts.

[0007] Optionally, the vinylidene chloride copolymer latex powder is generated by copolymerizing vinylidene chloride as the main monomer, polyvinyl alcohol as the emulsion system, and other monomers.

[0008] Optionally, the other monomers are selected from at least one of ethylene, butyl acrylate, isooctyl acrylate, lauryl acrylate, ethyl acrylate, and butyl methacrylate.

[0009] Optionally, the vinylidene chloride copolymer latex powder is selected from at least one of vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder, vinylidene chloride-isooctyl acrylate copolymer latex powder, vinylidene chloride-ethylene-lauryl acrylate copolymer latex powder, and vinylidene chloride-ethyl acrylate-butyl methacrylate copolymer latex powder.

[0010] Optionally, the vinylidene chloride copolymer latex powder is selected from at least one of vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder, vinylidene chloride-isooctyl acrylate copolymer latex powder, and vinylidene chloride-ethylene-laurate acrylate copolymer latex powder.

[0011] Optionally, the particle size of the heavy calcium carbonate is 300-400 mesh.

[0012] Optionally, the particle size of the lime powder is 300-400 mesh.

[0013] Optionally, the cellulose is selected from at least one of hydroxymethyl ethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose.

[0014] Optionally, the starch ether is hydroxypropyl starch ether.

[0015] Another object of the present invention is to provide a method for preparing the flame-retardant putty powder as described above, comprising the following steps: S1: Mix heavy calcium carbonate and hydrated lime powder according to the formula to obtain mixture A.

[0016] S2: Mix the mixture A, cellulose, starch ether, and vinylidene chloride copolymer latex powder according to the formula to obtain flame-retardant putty powder.

[0017] The beneficial effects of this invention are: The flame-retardant putty powder provided by this invention achieves a significant performance improvement through the synergistic effect of vinylidene chloride copolymer latex powder and its components. The addition of vinylidene chloride copolymer latex powder gives the putty powder of this invention excellent flame retardancy and achieves superior water resistance without the need for hydrophobic compounds or water-repellent agents. The formulation is simpler, the cost is lower, and it is more environmentally friendly. Detailed Implementation

[0018] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] To address the problem that existing putty powders lack flame retardancy, this invention provides a water-resistant putty powder, which, by weight, comprises the following components: 70-80 parts of heavy calcium carbonate; 20-30 parts of lime powder; 0.3-0.5 parts cellulose; Starch ether 0.05-1 part; Vinylidene chloride copolymer latex powder: 0.5-2 parts.

[0020] Vinylidene chloride copolymer latex powder is a redispersible latex powder, specifically a redispersible polymer powder prepared by copolymerizing vinylidene chloride as the main monomer with other monomers through emulsion. Due to the high chlorine content of vinylidene chloride, it provides a high oxygen index, thus endowing the putty powder with good flame retardant properties. Furthermore, due to the dense and crystalline molecular structure of vinylidene chloride, the vinylidene chloride copolymer latex powder prepared with vinylidene chloride as the main monomer has excellent barrier properties. Introducing this vinylidene chloride copolymer latex powder into putty powder can form a dense, continuous film, effectively preventing water penetration and giving the putty powder excellent hydrophobicity and impermeability, enabling the putty powder to achieve excellent water resistance without adding hydrophobic compounds or water-repellent agents.

[0021] The flame-retardant putty powder provided by this invention achieves a significant performance improvement through the synergistic effect of vinylidene chloride copolymer latex powder and its components. The addition of vinylidene chloride copolymer latex powder gives the putty powder of this invention excellent flame retardancy and achieves superior water resistance without the need for hydrophobic compounds or water-repellent agents. The formulation is simpler, the cost is lower, and it is more environmentally friendly.

[0022] The present invention preferably uses vinylidene chloride copolymer latex powder as the main monomer, polyvinyl alcohol as the emulsion system, and copolymerizes it with other monomers; further preferably, the other monomers are selected from at least one of ethylene, butyl acrylate, isooctyl acrylate, lauryl acrylate, ethyl acrylate, and butyl methacrylate.

[0023] The vinylidene chloride copolymer latex powder of this invention can be prepared according to the following method: S01: Dissolve a portion of polyvinyl alcohol (preferably 5 parts by weight) in deionized water, heat to 80-90℃, and after complete dissolution, obtain a polyvinyl alcohol aqueous solution, and keep the temperature at 70±1℃ for later use. S02: Dissolve the remaining polyvinyl alcohol (preferably 3 parts by weight) in deionized water, heat to 80-90°C, and after complete dissolution, cool to 40-50°C, add 70-90 parts by weight of vinylidene chloride, 5-15 parts by weight of other monomers and 0.1-0.5 parts by weight of chain transfer agent, and stir until completely dissolved to obtain a pre-emulsified mixture. S03: Dissolve 0.1-0.5 parts by weight of initiator in deionized water to obtain an initiator solution; S04: Take a portion of the pre-emulsified mixture and mix it with a polyvinyl alcohol aqueous solution, keep the temperature at 60±1℃, add 1 / 3 of the initiator solution, and start the reaction; S05: After the reaction has been going on for 1 hour, add the remaining pre-emulsified mixture and the remaining 2 / 3 of the initiator solution. After adding the mixture, continue to keep warm for another 2 hours. S06: Cool down to below 30℃, evacuate the reactor, condense and recover unreacted residual monomers, stop the vacuum pump, discharge, filter, and package to obtain vinylidene chloride copolymer emulsion; S07: The above vinylidene chloride copolymer emulsion, or vinylidene chloride copolymer emulsion and other emulsions at a mass ratio of 1:3, are spray-dried to obtain vinylidene chloride copolymer latex powder.

[0024] Preferably, the other emulsions mentioned above are selected from at least one of vinyl acetate-ethylene copolymer emulsion, vinyl acetate-acrylic emulsion, and acrylic emulsion.

[0025] Specifically, the vinylidene chloride copolymer latex powder of the present invention is preferably selected from at least one of vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder, vinylidene chloride-isooctyl acrylate copolymer latex powder, vinylidene chloride-ethylene-lauryl acrylate copolymer latex powder, and vinylidene chloride-ethyl acrylate-butyl methacrylate copolymer latex powder.

[0026] Furthermore, ethylene and isooctyl acrylate can impart good flexibility and bonding strength to putty powder. Therefore, the present invention preferably selects at least one of vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder, vinylidene chloride-isooctyl acrylate copolymer latex powder, and vinylidene chloride-ethylene-laurate copolymer latex powder, thereby improving the bonding strength of putty powder.

[0027] Furthermore, the present invention preferably uses heavy calcium carbonate with a particle size of 300-400 mesh to reduce costs and improve sandability; preferably uses lime powder with a particle size of 300-400 mesh to help improve the strength and hardness of putty powder and provide an alkaline environment; preferably uses cellulose selected from at least one of hydroxymethyl ethyl cellulose, hydroxyethyl cellulose and hydroxypropyl methyl cellulose; and preferably uses starch ether hydroxypropyl starch ether.

[0028] Another object of the present invention is to provide a method for preparing the water-resistant putty powder as described above, comprising the following steps: S1: Mix heavy calcium carbonate and hydrated lime powder according to the formula to obtain mixture A.

[0029] S2: Mix mixture A, cellulose, starch ether, and vinylidene chloride copolymer latex powder according to the formula to obtain water-resistant putty powder.

[0030] The method for preparing water-resistant putty powder provided by this invention is simple. The prepared flame-retardant putty powder achieves significant performance improvement through the synergistic effect of vinylidene chloride copolymer latex powder and other components. The addition of vinylidene chloride copolymer latex powder gives the putty powder provided by this invention excellent flame retardancy and achieves superior water resistance without the need for hydrophobic compounds or water-repellent agents. The formulation is simpler, the cost is lower, and it is more environmentally friendly.

[0031] The putty powder preparation method provided by this invention is simple, easy to operate, convenient to apply, and suitable for large-scale production, ensuring the consistency and reliability of product quality. The putty powder prepared by this method not only meets the market demand for high-performance putty powder, but its environmental protection characteristics also conform to the sustainable development trend of the modern construction industry.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0033] Unless otherwise specified, the VAE latex powder in the comparative examples of this invention was purchased from Shandong Fuyida Chemical Group Co., Ltd.; the acrylic latex powder was purchased from Shanghai Zengye Industrial Co., Ltd.; and the vinyl acetate-vinyl tert-carbonate copolymer latex powder was purchased from Shanghai Shunshui Chemical Co., Ltd.

[0034] Unless otherwise specified, the putty powders provided in the embodiments and comparative examples of this invention are prepared according to the following method: S0: Weigh out the heavy calcium carbonate, hydrated lime powder, cellulose, starch ether, and redispersible latex powder according to the formula and set aside. S:1: Place heavy calcium carbonate and hydrated lime powder into a grinder, grind thoroughly, and filter through a 200-300 mesh sieve to obtain mixture A; S2: Add mixture A, cellulose, starch ether, and redispersible latex powder to a mixing device and stir evenly to obtain flame-retardant, water-resistant, high-strength putty powder.

[0035] Example 1 This embodiment provides a flame-retardant putty powder, which, by weight, comprises the following components: 70 parts of heavy calcium carbonate; 20 parts of lime powder; 0.3 parts cellulose; 0.05 parts of starch ether; 0.5 parts of vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder; The heavy calcium carbonate and hydrated calcium powder have a particle size of 300 mesh, the cellulose is hydroxymethyl ethyl cellulose, and the starch ether is hydroxypropyl starch ether.

[0036] Vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder is prepared according to the following method: S01: Dissolve 5 parts by weight of polyvinyl alcohol in 60 parts by weight of deionized water, heat to 85°C, and after complete dissolution, obtain a polyvinyl alcohol aqueous solution. Keep the temperature at 70±1°C for later use. S2: Dissolve 3 parts by weight of polyvinyl alcohol in 35 parts by weight of deionized water, heat to 85°C, and after complete dissolution, cool to 45°C, add 80 parts by weight of vinylidene chloride, 5 parts by weight of butyl acrylate, 5 parts by weight of ethylene and 0.2 parts by weight of chain transfer agent, and stir until completely dissolved to obtain a pre-emulsified mixture. S3: Dissolve 0.2 parts by weight of initiator in 5 parts by weight of deionized water to obtain an initiator solution; S4: Take 25 parts by weight of the pre-emulsified mixture and mix it with the polyvinyl alcohol aqueous solution, keep the temperature at 60±1℃, add 1 / 3 of the initiator solution, and start the reaction; S5: After the reaction has been going on for 1 hour, add the remaining pre-emulsified mixture and the remaining 2 / 3 of the initiator solution. After adding the mixture, continue to keep warm for another 2 hours. S6: Cool down to below 30℃, evacuate the reactor to -0.09MPa, condense and recover unreacted residual monomers, stop the vacuum pump, discharge, filter, and package to obtain vinylidene chloride-ethylene-butyl acrylate terpolymer emulsion; S7: Spray dry the above vinylidene chloride copolymer emulsion to obtain vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder.

[0037] The degree of polymerization of polyvinyl alcohol is 1500-2500; the chain transfer agent is dodecyl mercaptan; and the initiator is potassium persulfate.

[0038] Example 2 This embodiment provides a flame-retardant putty powder, which, by weight, comprises the following components: 80 parts of heavy calcium carbonate; 30 parts of lime powder; 0.5 parts cellulose; 1 part starch ether; One part of vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder; 1 part of vinylidene chloride-isooctyl acrylate copolymer latex powder; The particle size of both the heavy calcium carbonate and the gray calcium powder is 400 mesh, the cellulose is hydroxypropyl ethyl methyl cellulose, and the starch ether is hydroxypropyl starch ether.

[0039] Preparation method of vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder (Example 1).

[0040] The preparation method of vinylidene chloride-isooctyl acrylate copolymer latex powder is as follows: S01: Dissolve 5 parts by weight of polyvinyl alcohol in 60 parts by weight of deionized water, heat to 85°C, and after complete dissolution, obtain a polyvinyl alcohol aqueous solution. Keep the temperature at 70±1°C for later use. S2: Dissolve 3 parts by weight of polyvinyl alcohol in 35 parts by weight of deionized water, heat to 85°C, and after complete dissolution, cool to 45°C, add 80 parts by weight of vinylidene chloride, 10 parts by weight of isooctyl acrylate and 0.2 parts by weight of chain transfer agent, and stir until completely dissolved to obtain a pre-emulsified mixture. S3: Dissolve 0.2 parts by weight of initiator in 5 parts by weight of deionized water to obtain an initiator solution; S4: Take 25 parts by weight of the pre-emulsified mixture and mix it with the polyvinyl alcohol aqueous solution, keep the temperature at 60±1℃, add 1 / 3 of the initiator solution, and start the reaction; S5: After the reaction has been going on for 1 hour, add the remaining pre-emulsified mixture and the remaining 2 / 3 of the initiator solution. After adding the mixture, continue to keep warm for another 2 hours. S6: Cool down to below 30℃, evacuate the reactor to -0.09MPa, condense and recover unreacted residual monomers, stop the vacuum pump, discharge, filter, and package to obtain vinylidene chloride-ethylene-butyl acrylate terpolymer emulsion; S7: Spray dry the above vinylidene chloride copolymer emulsion to obtain vinylidene chloride-isooctyl acrylate copolymer latex powder.

[0041] The degree of polymerization of polyvinyl alcohol is 1500-2500; the chain transfer agent is dodecyl mercaptan; and the initiator is potassium persulfate.

[0042] Example 3 This embodiment provides a flame-retardant putty powder, which, by weight, comprises the following components: 75 parts of heavy calcium carbonate; 25 parts of lime powder; 0.4 parts cellulose; Starch ether 0.06 parts; One part of vinylidene chloride-ethylene-laurate copolymer latex powder; The particle size of both the heavy calcium carbonate and the hydrated lime powder is 300 mesh, the cellulose is hydroxymethyl ethyl cellulose, and the starch ether is hydroxypropyl starch ether.

[0043] The preparation method of vinylidene chloride-ethylene-laurate copolymer latex powder is as follows: S01: Dissolve 5 parts by weight of polyvinyl alcohol in 60 parts by weight of deionized water, heat to 85°C, and after complete dissolution, obtain a polyvinyl alcohol aqueous solution. Keep the temperature at 70±1°C for later use. S2: Dissolve 3 parts by weight of polyvinyl alcohol in 35 parts by weight of deionized water, heat to 85°C, and after complete dissolution, cool to 45°C. Add 80 parts by weight of vinylidene chloride, 5 parts by weight of lauryl acrylate, 5 parts by weight of ethylene and 0.2 parts by weight of chain transfer agent, and stir until completely dissolved to obtain a pre-emulsified mixture. S3: Dissolve 0.2 parts by weight of initiator in 5 parts by weight of deionized water to obtain an initiator solution; S4: Take 25 parts by weight of the pre-emulsified mixture and mix it with the polyvinyl alcohol aqueous solution, keep the temperature at 60±1℃, add 1 / 3 of the initiator solution, and start the reaction; S5: After the reaction has been going on for 1 hour, add the remaining pre-emulsified mixture and the remaining 2 / 3 of the initiator solution. After adding the mixture, continue to keep warm for another 2 hours. S6: Cool down to below 30℃, evacuate the reactor to -0.09MPa, condense and recover unreacted residual monomers, stop the vacuum pump, discharge, filter, and package to obtain vinylidene chloride-ethylene-butyl acrylate terpolymer emulsion; S7: Spray dry the above vinylidene chloride copolymer emulsion to obtain vinylidene chloride-ethylene-laurate copolymer latex powder.

[0044] The degree of polymerization of polyvinyl alcohol is 1500-2500; the chain transfer agent is dodecyl mercaptan; and the initiator is potassium persulfate.

[0045] Example 4 This embodiment provides a flame-retardant putty powder, which, by weight, comprises the following components: 78 parts of heavy calcium carbonate; 28 parts of lime powder; 0.4 parts cellulose; Starch ether 0.07 parts; 1 part of vinylidene chloride-isooctyl acrylate copolymer latex powder; 0.5 parts of vinylidene chloride-ethyl acrylate-butyl methacrylate copolymer latex powder; The particle size of both the heavy calcium carbonate and the hydrated lime powder is 400 mesh, the cellulose is hydroxyethyl cellulose, and the starch ether is hydroxypropyl starch ether.

[0046] The preparation method of vinylidene chloride-isooctyl acrylate copolymer latex powder is the same as that in Example 2; The preparation method of vinylidene chloride-ethyl acrylate-butyl methacrylate copolymer latex powder is as follows: S01: Dissolve 5 parts by weight of polyvinyl alcohol in 60 parts by weight of deionized water, heat to 85°C, and after complete dissolution, obtain a polyvinyl alcohol aqueous solution. Keep the temperature at 70±1°C for later use. S2: Dissolve 3 parts by weight of polyvinyl alcohol in 35 parts by weight of deionized water, heat to 85°C, and after complete dissolution, cool to 45°C, add 80 parts by weight of vinylidene chloride, 5 parts by weight of ethyl acrylate, 5 parts by weight of butyl methacrylate and 0.2 parts by weight of chain transfer agent, stir until completely dissolved, and obtain a pre-emulsified mixture. S3: Dissolve 0.2 parts by weight of initiator in 5 parts by weight of deionized water to obtain an initiator solution; S4: Take 25 parts by weight of the pre-emulsified mixture and mix it with the polyvinyl alcohol aqueous solution, keep the temperature at 60±1℃, add 1 / 3 of the initiator solution, and start the reaction; S5: After the reaction has been going on for 1 hour, add the remaining pre-emulsified mixture and the remaining 2 / 3 of the initiator solution. After adding the mixture, continue to keep warm for another 2 hours. S6: Cool down to below 30℃, evacuate the reactor to -0.09MPa, condense and recover unreacted residual monomers, stop the vacuum pump, discharge, filter, and package to obtain vinylidene chloride-ethylene-butyl acrylate terpolymer emulsion; S7: Spray dry the above vinylidene chloride copolymer emulsion to obtain vinylidene chloride-ethyl acrylate-butyl methacrylate copolymer latex powder.

[0047] The degree of polymerization of polyvinyl alcohol is 1500-2500; the chain transfer agent is dodecyl mercaptan; and the initiator is potassium persulfate.

[0048] Comparative Example 1 This comparative example provides a flame-retardant putty powder, which, by weight, comprises the following components: 70 parts of heavy calcium carbonate; 20 parts of lime powder; 0.3 parts cellulose; 0.05 parts of starch ether; 0.5 parts EVA latex powder; The heavy calcium carbonate and hydrated calcium powder have a particle size of 300 mesh, the cellulose is hydroxymethyl ethyl cellulose, and the starch ether is hydroxypropyl starch ether.

[0049] Comparative Example 2 This comparative example provides a flame-retardant putty powder, which, by weight, comprises the following components: 70 parts of heavy calcium carbonate; 20 parts of lime powder; 0.3 parts cellulose; 0.05 parts of starch ether; 0.5 parts acrylic latex powder; The heavy calcium carbonate and hydrated calcium powder have a particle size of 300 mesh, the cellulose is hydroxymethyl ethyl cellulose, and the starch ether is hydroxypropyl starch ether.

[0050] Comparative Example 3 This comparative example provides a flame-retardant putty powder, which, by weight, comprises the following components: 70 parts of heavy calcium carbonate; 20 parts of lime powder; 0.3 parts cellulose; 0.05 parts of starch ether; 0.5 parts of vinyl acetate-vinyl tert-carbonate copolymer latex powder; The heavy calcium carbonate and hydrated calcium powder have a particle size of 300 mesh, the cellulose is hydroxymethyl ethyl cellulose, and the starch ether is hydroxypropyl starch ether.

[0051] Comparative Example 4 This comparative example provides a flame-retardant putty powder, which, by weight, comprises the following components: 70 parts of heavy calcium carbonate; 20 parts of lime powder; 0.3 parts cellulose; 0.05 parts of starch ether; 0.5 parts of vinyl chloride-ethylene-butyl acrylate terpolymer latex powder; The heavy calcium carbonate and hydrated calcium powder have a particle size of 300 mesh, the cellulose is hydroxymethyl ethyl cellulose, and the starch ether is hydroxypropyl starch ether.

[0052] Vinyl chloride-ethylene-butyl acrylate terpolymer latex powder is prepared according to the following method: S1: Dissolve 5 parts by weight of polyvinyl alcohol in 60 parts by weight of deionized water, heat to 85°C, and after complete dissolution, obtain a polyvinyl alcohol aqueous solution. Keep the temperature at 70±1°C for later use. S2: Dissolve 3 parts by weight of polyvinyl alcohol in 35 parts by weight of deionized water, heat to 85°C, and after complete dissolution, cool to 45°C, add 80 parts by weight of vinyl chloride, 5 parts by weight of ethylene, 5 parts by weight of butyl acrylate, 0.2 parts by weight of initiator and 0.2 parts by weight of chain transfer agent, and stir until completely dissolved to obtain a pre-emulsified mixture. S3: Dissolve 0.2 parts by weight of initiator in 5 parts by weight of deionized water to obtain an initiator solution; S4: Take 25 parts by weight of the pre-emulsified mixture and mix it with the polyvinyl alcohol aqueous solution, keep the temperature at 60±1℃, add 1 / 3 of the initiator solution, and start the reaction; S5: After the reaction has been going on for 1 hour, add the remaining pre-emulsified mixture and the remaining 2 / 3 of the initiator solution. After adding the mixture, continue to keep warm for another 2 hours. S6: Cool down to below 30℃, evacuate the reactor to -0.09MPa, condense and recover unreacted residual monomers, stop the vacuum pump, discharge, filter, and package to obtain vinyl chloride copolymer emulsion.

[0053] S7: Spray dry the above vinyl chloride copolymer emulsion to obtain vinyl chloride copolymer latex powder.

[0054] The degree of polymerization of polyvinyl alcohol is 1500-2500; the chain transfer agent is dodecyl mercaptan; and the initiator is potassium persulfate.

[0055] The properties of the putty powders prepared in the above embodiments and comparative examples were tested. The specific test process is as follows: 1. Add the putty powder and water prepared in the various embodiments and comparative examples of the present invention to a mixing device at a mass ratio of 1:0.5, and stir for 5 minutes to obtain the putty to be tested.

[0056] 2. Flame retardancy test: The test method was carried out according to GB 8624-2012 standard, and the flame retardancy test results are shown in Table 1; 3. Water resistance test: The test method is based on JG / T 298-2010 standard. The water resistance test results are shown in Table 2.

[0057] 4. Bond strength test: The test method is carried out in accordance with JG / T 298-2010 standard. The bond strength test results are shown in Table 3.

[0058] Table 1 As can be seen from Table 1, the flame retardant effect of the putty powder prepared in each embodiment of the present invention is significantly better than that of the comparative example, indicating that the putty powder prepared in the present invention has excellent flame retardant effect.

[0059] Table 2 As can be seen from Table 2, the water resistance of the putty powder with high water resistance prepared in each embodiment of the present invention has been effectively improved, indicating that the putty powder prepared by the present invention has excellent water resistance.

[0060] Table 3 As can be seen from Table 3, the putty powder prepared in each embodiment of the present invention has high water resistance and maintains high bonding strength after water immersion treatment, which is a significant improvement compared with the comparative example.

[0061] In summary, the difference between Comparative Example 1 and Example 1 is that the added latex powder is EVA latex powder. The resulting putty powder has lower flame retardancy and water resistance than that of Example 1, and the bonding strength after soaking in water is significantly reduced. This is due to the addition of chlorine-containing latex powder with excellent flame retardancy and water resistance.

[0062] The difference between Comparative Example 2 and Example 1 is that the added latex powder is acrylic latex powder. Although the resulting putty powder has better water resistance than VAE latex powder, it is still not as good as vinylidene chloride latex powder.

[0063] The difference between Comparative Example 3 and Example 1 is that the added latex powder is vinyl acetate-vinyl tert-carbonate copolymer latex powder. The resulting putty powder has better water resistance than VAE latex powder, but the putty powder prepared from vinylidene chloride latex powder still has a much better water resistance.

[0064] The difference between Comparative Example 4 and Example 1 is that the added latex powder is vinyl chloride copolymer latex powder. Its flame retardant properties and water resistance are not as good as those of Example 1. This is because the chlorine content of vinyl chloride latex powder is higher than that of vinyl chloride. In addition, the high crystallinity of vinyl chloride results in high barrier properties, which makes vinyl chloride latex powder more water resistant than vinyl chloride latex powder.

[0065] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A fire-retardant putty powder, characterized by, The raw materials comprise the following components in parts by weight: Heavy calcium carbonate 70-80 parts; Ground calcium powder 20-30 parts; Cellulose 0.3-0.5 parts; Starch ether 0.05-1 part; Vinylidene chloride-based copolymer latex powder 0.5-2 parts.

2. The fire-retardant putty powder according to claim 1, wherein The vinylidene chloride-based copolymer latex powder is copolymerized with other monomers using vinylidene chloride as the main monomer and polyvinyl alcohol as the emulsifying system.

3. The fire-retardant putty powder according to claim 2, wherein The other monomers are at least one selected from ethylene, butyl acrylate, isooctyl acrylate, lauryl acrylate, ethyl acrylate, and butyl methacrylate.

4. The fire-retardant putty powder according to claim 3, wherein The vinylidene chloride-based copolymer latex powder is at least one selected from vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder, vinylidene chloride-isooctyl acrylate copolymer latex powder, vinylidene chloride-ethylene-lauryl acrylate copolymer latex powder, and vinylidene chloride-ethyl acrylate-butyl methacrylate copolymer latex powder.

5. The fire-retardant putty powder according to claim 4, wherein The vinylidene chloride-based copolymer latex powder is at least one selected from vinylidene chloride-ethylene-butyl acrylate terpolymer latex powder, vinylidene chloride-isooctyl acrylate copolymer latex powder, and vinylidene chloride-ethylene-lauryl acrylate copolymer latex powder.

6. A fire-retardant putty according to any one of claims 1 to 5, characterised in that, The particle size of the heavy calcium carbonate is 300-400 mesh.

7. A fire-retardant putty according to any one of claims 1 to 5, characterised in that, The particle size of the ground calcium powder is 300-400 mesh.

8. A fire-retardant putty according to any one of claims 1 to 5, characterised in that, The cellulose is at least one selected from hydroxymethyl ethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose.

9. A fire-retardant putty according to any one of claims 1 to 5, characterised in that, The starch ether is hydroxypropyl starch ether.

10. A process for the preparation of a fire-retardant putty powder according to any one of claims 1 to 9, characterized in that The method comprises the following steps: S1: mixing heavy calcium carbonate and ground calcium powder according to the formula amount to obtain a mixture A. S2: mixing the mixture A, cellulose, starch ether, and vinylidene chloride-based copolymer latex powder according to the formula amount to obtain a fire-retardant putty powder.

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