Method for preparing vinyl chloride copolymer

Abstract

The invention discloses a method for preparing a vinyl chloride copolymer, and belongs to the technical field of high-molecular polymerization. The vinyl chloride copolymer is prepared from the following raw materials in parts by weight: vinyl chloride, a second monomer, a third monomer and / or a polymer; wherein the second monomer is selected from one or more of vinyl ester monomers; the third monomer is selected from one or more of an acrylate monomer, a vinyl ether monomer, an aryl vinyl monomer, maleic acid and anhydride / ester monomers thereof, and a vinyl halide monomer; the polymer is a polymer capable of being grafted and copolymerized; compared with SG3 and SG5 type PVC resin, when the vinyl chloride copolymer prepared by adjusting the proportion and feeding mode of the materials is used for preparing soft products, the soft products with higher physical properties can be obtained only by adding less parts of plasticizer, and the vinyl chloride copolymer has very excellent market value.

Description

Technical Field

[0001] The invention relates to the technical field of polymer polymerization, and in particular to a method for preparing a vinyl chloride copolymer. Background Art

[0002] Polyvinyl chloride (PVC) is one of the five major general-purpose plastics, with the advantages of good comprehensive mechanical properties, flame retardancy, corrosion resistance, and environmental protection. As an important chlorine-consuming, "plastic-steel" and "plastic-wood" material, PVC is widely used in the production of building profiles, pipes, membrane products, plates, artificial leather, wires and cables, luggage, sports products, etc. In addition to being used to produce hard products, PVC is also used to produce semi-rigid and soft products by adding plasticizers. At present, PVC consumed in the form of soft products accounts for about 30% of the total PVC consumption, and the plasticizers consumed by semi-rigid and soft PVC products account for more than 80% of the total plasticizer consumption. Plasticizers are usually small molecule compounds, among which phthalates are the most commonly used, such as diethylhexyl phthalate, diisooctyl phthalate (DOP), dibutyl phthalate, etc. These plasticizers have good compatibility with PVC and can be inserted between PVC molecular chains to reduce the intermolecular forces and increase the activity of the molecular chains, thereby reducing the glass transition temperature of PVC. However, during the processing and use of PVC, small molecule plasticizers will still migrate and seep from the products to the environment and contact objects. In polyvinyl chloride plastic products, in order to increase the plasticity and strength of the plastic, phthalate plasticizers need to be added, and their content can sometimes exceed the amount of PVC in the formula. The use of plasticizers greatly increases costs, and phthalates, especially DOP, are potentially carcinogenic, which will cause environmental pollution and health problems for contact personnel. In addition, PVC products using small molecule plasticizers also have disadvantages such as high-temperature deformation resistance (creep) and poor low-temperature flexibility. Moreover, as the plasticizer gradually migrates and seeps out, the performance and color of the product will also change, such as increased hardness, decreased flexibility and elasticity, and yellowing. Summary of the invention

[0003] In view of the problems existing in the prior art in the application of PVC in soft products, the present invention provides a method for preparing a vinyl chloride copolymer. The present invention realizes internal plasticization of PVC by changing the molecular chain structure of PVC, copolymerizes PVC with a monomer or polymer that can reduce the glass transition temperature of vinyl chloride-based resin, destroys the regularity of the PVC polymer molecular chain, reduces the crystallinity of the PVC polymer, reduces the force between PVC molecules, increases the plasticity of PVC, reduces the use of small molecule plasticizers, and overcomes the migration of small molecule plasticizers, thereby obtaining an environmentally friendly, good-performance and stable internal plasticized PVC. The internal plasticized PVC of the present invention can meet the application of various soft products without or with less plasticizers.

[0004] To achieve the above purpose, the specific technical solutions of the present invention are as follows:

[0005] The present invention provides a method for preparing a vinyl chloride copolymer, wherein the vinyl chloride copolymer is prepared by any one of the following three methods:

[0006] Method I comprises the following steps: after uniformly mixing the whole amount of the second monomer, dispersant, initiator, deionized water, pH regulator, auxiliary agent, 60%-100% of the amount of vinyl chloride, and 20%-60% of the amount of the third monomer, the temperature of the reaction system is raised to 40-70°C to carry out polymerization reaction, when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, the remaining vinyl chloride (if 100% of the amount of vinyl chloride is added as mentioned above, the remaining amount of vinyl chloride here is 0, and no more vinyl chloride needs to be added) and the third monomer are added dropwise, and after the addition is completed, the reaction is continued until the pressure of the reactor drops to 0.20-0.30 MPa, a terminator is added, and the material is discharged;

[0007] The weight ratio of vinyl chloride, the second monomer and the third monomer is (50-90): (5-25): (5-25);

[0008] The second monomer is selected from one or more vinyl ester monomers;

[0009] The third monomer is selected from one or more of acrylate monomers, vinyl ether monomers, aromatic vinyl monomers, maleic acid and its anhydride / ester monomers, and vinyl halide monomers.

[0010] Method II comprises the following steps: after uniformly mixing the whole amount of the second monomer, dispersant, initiator, deionized water, pH regulator, auxiliary agent, polymer, and 60%-100% of the amount of vinyl chloride, raising the temperature of the reaction system to 40-70°C to carry out polymerization reaction, when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, starting to drop the remaining vinyl chloride (if 100% of the amount of vinyl chloride is added as mentioned above, the remaining amount of vinyl chloride here is 0, and no more vinyl chloride needs to be added), continuing the reaction after the dropwise addition is completed until the pressure of the reactor drops to 0.20-0.30 MPa, adding a terminator, and discharging;

[0011] The weight ratio of vinyl chloride, the second monomer and the polymer is (50-90): (5-25): (5-25);

[0012] The second monomer is selected from one or more vinyl ester monomers;

[0013] The polymer is a graft copolymerizable polymer; the graft copolymerizable polymer is a resin or elastomer obtained by polymerization of mixed monomers, such as EVA resin, EVM elastomer, nitrile rubber, etc.; the mixed monomer is composed of C n H 2n The structure of substituted monoolefins and C n H (2n-2) The structure is obtained by mixing one or more substituted dienes.

[0014] Method III comprises the following steps: after uniformly mixing the whole amount of the second monomer, dispersant, initiator, deionized water, pH regulator, auxiliary agent, polymer, 60%-100% of the amount of vinyl chloride, and 20%-60% of the amount of the third monomer, raising the temperature of the reaction system to 40-70°C to carry out polymerization reaction, when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, starting to drop the remaining vinyl chloride (if 100% of the amount of vinyl chloride is added as mentioned above, the remaining amount of vinyl chloride here is 0, and no more vinyl chloride needs to be added) and the third monomer, continuing the reaction after the dropwise addition is completed, until the pressure of the reactor drops to 0.20-0.30 MPa, adding a terminator, and discharging;

[0015] The weight ratio of vinyl chloride, the second monomer, the third monomer, and the polymer is (50-90): (5-25): (2-15): (2-15);

[0016] The second monomer is selected from one or more vinyl ester monomers;

[0017] The third monomer is selected from one or more of acrylate monomers, vinyl ether monomers, aromatic vinyl monomers, maleic acid and its anhydride / ester monomers, and vinyl halide monomers;

[0018] The polymer is a graft copolymerizable polymer; the graft copolymerizable polymer is a resin or elastomer obtained by polymerization of mixed monomers, such as EVA resin, EVM elastomer, nitrile rubber, etc.; the mixed monomer is composed of C n H 2n The structure of substituted monoolefins and C n H (2n-2) The structure is obtained by mixing one or more substituted dienes.

[0019] Preferably, the vinyl ester monomer contains both a vinyl group and an ester group, and the vinyl ester monomer includes but is not limited to vinyl acetate and vinyl versatate.

[0020] Preferably, the alkyl chain of the linear, branched, or cyclic alcohol of the acrylic ester monomer contains 1 to 12 carbon atoms, and the acrylic ester monomer includes but is not limited to methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, cyclohexyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, ethylhexyl methacrylate, and cyclohexyl methacrylate;

[0021] Preferably, the maleic acid and its anhydride and ester monomers include but are not limited to diethyl fumarate, dimethyl itaconate, diethyl itaconate, diisopropyl itaconate, and dioctyl itaconate.

[0022] Preferably, the polymerization reaction is a constant temperature polymerization reaction or a variable temperature polymerization reaction.

[0023] Preferably, the dispersant is one or more selected from polyvinyl alcohol, gelatin, cellulose, polyethylene oxide, and polyvinyl pyrrolidone.

[0024] Preferably, the initiator is selected from one or more of an organic peroxide initiator and an azo initiator; wherein the organic peroxide initiator is insoluble in water, including but not limited to di(3,5,6-trimethylhexanoyl) peroxide, tert-butyl peroxypivalate, isopropyl peroxypivalate, tert-butyl peroxypivalate, and di(2-ethylhexyl) peroxydicarbonate; the azo initiator includes but not limited to azobisisobutyronitrile and azobisisoheptanoonitrile.

[0025] Preferably, the pH regulator is selected from one or more of sodium bicarbonate (baking soda), ammonium bicarbonate, ammonia water, sodium carbonate, and triethanolamine.

[0026] Preferably, the auxiliary agent includes one or more of a chain regulator, a surfactant, and a water phase inhibitor.

[0027] More preferably, the chain regulator is selected from one or more of mercaptoethanol and its derivatives, and trichloroethylene.

[0028] Further preferably, the surfactant is selected from one or more of 12-18 C fatty acid salts, 10-18 C sulfonates, 8-10 C sulfosuccinate salts, and polyethylene oxide; wherein the 12-18 C fatty acid salts include but are not limited to sodium myristate and sodium palmitate; the 10-18 C sulfonates include but are not limited to sodium dodecyl sulfonate, sodium heptadecane sulfonate, sodium carboxymethyl sulfonate, sodium dodecylbenzene sulfonate, and sodium octylbenzene sulfonate; the 8-10 C sulfosuccinate salts include but are not limited to dihexyl sodium sulfosuccinate and didodecyl sodium sulfosuccinate.

[0029] Further preferably, the water phase inhibitor is selected from one or more of sodium sulfide, water-soluble black, alcohol-soluble black, and methylene blue.

[0030] Preferably, the terminator is selected from one or more of hindered phenol terminators, phosphite terminators, aromatic amine terminators, thioester terminators, thiophenol terminators, hydroxylamine terminators, and thiosemicarbazide terminators.

[0031] Preferably, the method for preparing the vinyl chloride copolymer includes a suspension method, a microsuspension method, and an emulsion method.

[0032] The present invention provides a vinyl chloride copolymer, wherein the raw materials thereof include, by weight: 50-90 parts of vinyl chloride, 5-25 parts of a second monomer, 5-25 parts of a third monomer / polymer, 0.15-0.25 parts of a dispersant, 0.46-0.60 parts of an initiator, 150-160 parts of deionized water, 0-0.3 parts of a pH regulator, 0-0.3 parts of an auxiliary agent, and 0.1-0.2 parts of a terminator;

[0033] Alternatively, the raw materials include, by weight: 50-90 parts of vinyl chloride, 5-25 parts of a second monomer, 2-15 parts of a third monomer, 2-15 parts of a polymer, 0.15-0.25 parts of a dispersant, 0.46-0.60 parts of an initiator, 150-160 parts of deionized water, 0-0.3 parts of a pH regulator, 0-0.3 parts of an auxiliary agent, and 0.1-0.2 parts of a terminator.

[0034] The present invention also provides a vinyl chloride copolymer prepared by the method or application of the vinyl chloride copolymer in soft products.

[0035] The present invention adopts a method of copolymerizing a second monomer, a third monomer and / or a polymer capable of lowering the glass transition temperature of polyvinyl chloride with vinyl chloride to destroy the regularity of the polyvinyl chloride molecular chain, reduce the crystallinity of the polyvinyl chloride polymer, reduce the intermolecular force of polyvinyl chloride, and increase the plasticity of polyvinyl chloride; and by adjusting the ratio of various materials, the feeding method, and controlling the reaction temperature, pressure and time, the prepared vinyl chloride copolymer has good ductility. When the copolymer is used to make soft products, no or little plasticizer can be added to obtain a soft product with excellent physical properties.

[0036] Compared with the prior art, the present invention is beneficial in that:

[0037] (1) The present invention uses the second monomer, the third monomer and / or the polymer to copolymerize with vinyl chloride to prepare a multi-component vinyl chloride copolymer having good ductility. When the copolymer is used for soft products, compared with the commonly used SG3 and SG5 PVC resins on the market, the vinyl chloride copolymer of the present invention can be added with less or no plasticizer, that is, a soft product with excellent physical properties can be obtained;

[0038] (2) The vinyl chloride copolymer prepared by the present invention has a low glass transition temperature and can be used in a variety of application fields, such as wires and cables with low plasticizer addition amounts. In addition, the vinyl chloride copolymer of the present invention is combined with a low dose of plasticizer, wherein the plasticizer has low migration, and can be used to replace medical or food contact PVC soft products. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be 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.

[0040] The present invention provides a method for preparing a vinyl chloride copolymer, wherein the vinyl chloride copolymer is prepared by any one of the following three methods:

[0041] Method I comprises the following steps: after uniformly mixing the whole amount of the second monomer, the dispersant, the initiator, the deionized water, the pH regulator, the auxiliary agent, 60%-100% of the amount of vinyl chloride, and 20%-60% of the amount of the third monomer, the temperature of the reaction system is raised to 40-70°C to carry out a polymerization reaction, when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, the remaining vinyl chloride and the third monomer are added dropwise, and after the addition is completed, the reaction is continued until the pressure of the reactor drops to 0.20-0.30 MPa, a terminator is added, and the material is discharged;

[0042] The weight ratio of vinyl chloride, the second monomer and the third monomer is (50-90): (5-25): (5-25);

[0043] The second monomer is selected from one or more vinyl ester monomers;

[0044] The third monomer is selected from one or more of acrylate monomers, vinyl ether monomers, aromatic vinyl monomers, maleic acid and its anhydride / ester monomers, and vinyl halide monomers.

[0045] Method II comprises the following steps: after uniformly mixing the whole amount of the second monomer, dispersant, initiator, deionized water, pH regulator, auxiliary agent, polymer, and 60%-100% of the amount of vinyl chloride, raising the temperature of the reaction system to 40-70° C. to carry out polymerization reaction, when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, starting to drop the remaining vinyl chloride, and continuing the reaction after the dropwise addition is completed until the pressure of the reactor drops to 0.20-0.30 MPa, adding a terminator, and discharging the material;

[0046] The weight ratio of vinyl chloride, the second monomer and the polymer is (50-90): (5-25): (5-25);

[0047] The second monomer is selected from one or more vinyl ester monomers;

[0048] The polymer is a graft copolymerizable polymer; the graft copolymerizable polymer is a resin or elastomer obtained by polymerization of mixed monomers, such as EVA resin, EVM elastomer, nitrile rubber, etc.; the mixed monomer is composed of C n H 2n The structure of substituted monoolefins and C n H (2n-2) The structure is obtained by mixing one or more substituted dienes.

[0049] Method III comprises the following steps: after uniformly mixing the whole amount of the second monomer, dispersant, initiator, deionized water, pH regulator, auxiliary agent, polymer, 60%-100% of the amount of vinyl chloride, and 20%-60% of the amount of the third monomer, raising the temperature of the reaction system to 40-70°C to carry out polymerization reaction, and when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, starting to drop the remaining vinyl chloride and the third monomer, and continuing the reaction after the dropwise addition is completed until the pressure of the reactor drops to 0.20-0.30 MPa, adding a terminator, and discharging the material;

[0050] The weight ratio of vinyl chloride, the second monomer, the third monomer, and the polymer is (50-90): (5-25): (2-15): (2-15);

[0051] The second monomer is selected from one or more vinyl ester monomers;

[0052] The third monomer is selected from one or more of acrylate monomers, vinyl ether monomers, aromatic vinyl monomers, maleic acid and its anhydride / ester monomers, and vinyl halide monomers;

[0053] The polymer is a graft copolymerizable polymer; the graft copolymerizable polymer is a resin or elastomer obtained by polymerization of mixed monomers, such as EVA resin, EVM elastomer, nitrile rubber, etc.; the mixed monomer is composed of C n H 2n The structure of substituted monoolefins and C n H (2n-2) The structure is obtained by mixing one or more substituted dienes.

[0054] In some examples, the vinyl ester monomers include, but are not limited to, vinyl acetate and vinyl versatate.

[0055] In some examples, the alkyl chain of the straight chain, branched chain, or cyclic alcohol of the acrylic ester monomer contains 1 to 12 carbon atoms, and the acrylic ester monomer includes but is not limited to methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, tert-butyl acrylate, pentyl acrylate, isopentyl acrylate, cyclohexyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, isopentyl methacrylate, ethylhexyl methacrylate, and cyclohexyl methacrylate.

[0056] In some examples, the maleic acid and its anhydride and ester monomers include, but are not limited to, diethyl fumarate, dimethyl itaconate, diethyl itaconate, diisopropyl itaconate, and dioctyl itaconate.

[0057] In some examples, the dispersant is one or more selected from polyvinyl alcohol, gelatin, cellulose, polyethylene oxide, and polyvinyl pyrrolidone.

[0058] In some examples, the initiator is selected from one or more of an organic peroxide initiator and an azo initiator; wherein the organic peroxide initiator is insoluble in water, including but not limited to di(3,5,6-trimethylhexanoyl) peroxide, tert-butyl peroxypivalate, isopropyl peroxypivalate, tert-butyl peroxypivalate, and di(2-ethylhexyl) peroxydicarbonate; the azo initiator includes but is not limited to azobisisobutyronitrile and azobisisoheptanoonitrile.

[0059] In some examples, the pH adjuster is selected from one or more of sodium bicarbonate (baking soda), ammonium bicarbonate, ammonia water, sodium carbonate, and triethanolamine; the auxiliary agent includes one or more of a chain regulator, a surfactant, and an aqueous phase inhibitor; the chain regulator is selected from one or more of mercaptoethanol and its derivatives, and trichloroethylene; the surfactant is selected from one or more of 12-18 C fatty acid salts, 10-18 C sulfonates, 8-10 C sulfosuccinate salts, and polyethylene oxide; wherein the 12-18 C fatty acid salts include but are not limited to sodium tetradecanoate and sodium palmitate; the 10-18 C sulfonates include but are not limited to sodium dodecyl sulfonate, sodium heptadecane sulfonate, sodium carboxymethyl sulfonate, sodium dodecylbenzene sulfonate, and sodium octylbenzene sulfonate; the 8-10 C sulfosuccinate salts include but are not limited to sodium dihexyl sulfosuccinate and sodium didodecyl sulfosuccinate; the aqueous phase inhibitor is selected from one or more of sodium sulfide, water-soluble black, alcohol-soluble black, and methylene blue.

[0060] In some examples, the terminator is selected from one or more of hindered phenol terminators, phosphite terminators, aromatic amine terminators, thioester terminators, thiophenol terminators, hydroxylamine terminators, and semicarbazide terminators.

[0061] In some examples, the method for preparing the vinyl chloride copolymer includes a suspension method, a microsuspension method, and an emulsion method.

[0062] Example 1

[0063] A vinyl chloride copolymer, the preparation steps are as follows:

[0064] (1) In terms of weight, 85 parts of vinyl chloride, 5 parts of the second monomer, 10 parts of the third monomer, 0.18 parts of the dispersant, 0.50 parts of the initiator, 160 parts of deionized water, 0.2 parts of the pH regulator, 0.3 parts of the auxiliary agent, and 0.15 parts of the terminator are prepared for use; the second monomer is vinyl acetate; the third monomer is butyl acrylate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:1; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate and hexadecanol in a weight ratio of 1:1; the terminator is TAA (thioacetamide); the method used in this example is a suspension method;

[0065] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.2 parts of pH adjuster, 0.3 parts of auxiliary agent, 85 parts of vinyl chloride, 5 parts of second monomer, and 4 parts of third monomer were added into the sealed reactor. The mixture was stirred for 30 minutes. The temperature of the reaction system was raised to 60°C, and then the reaction was carried out at a constant temperature. When the pressure of the reactor dropped by 0.10 MPa, the remaining 6 parts of the third monomer were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry.

[0066] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0067] Example 2

[0068] A vinyl chloride copolymer, the preparation steps are as follows:

[0069] (1) In terms of weight, 80 parts of vinyl chloride, 10 parts of the second monomer, 10 parts of the third monomer, 0.24 parts of a dispersant, 0.55 parts of an initiator, 160 parts of deionized water, 0.18 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator are prepared for use; the second monomer is vinyl acetate; the third monomer is isooctyl acrylate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 2:1; the initiator is azobisisoheptanenitrile; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate; the terminator is TAA; the method used in this example is a suspension method;

[0070] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.24 parts of dispersant, 0.55 parts of initiator, 0.18 parts of pH adjuster, 0.3 parts of auxiliary agent, 80 parts of vinyl chloride, 10 parts of second monomer, and 4 parts of third monomer were added into the sealed reactor. The mixture was stirred for 30 minutes. The temperature of the reaction system was raised to 57 °C, and then the reaction was carried out at a constant temperature. When the reaction time reached 1.5 h, the remaining 6 parts of the third monomer were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry.

[0071] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0072] Example 3

[0073] A vinyl chloride copolymer, the preparation steps are as follows:

[0074] (1) In terms of weight, prepare 75 parts of vinyl chloride, 10 parts of the second monomer, 15 parts of the third monomer, 0.25 parts of a dispersant, 0.60 parts of an initiator, 160 parts of deionized water, 0.15 parts of a pH regulator, 0.33 parts of an auxiliary agent, and 0.15 parts of a terminator for use; the second monomer is tert-butyl carbonate; the third monomer is butyl acrylate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 2:3; the initiator is di(2-ethylhexyl) peroxydicarbonate and azobisisoheptonitrile; the pH regulator is sodium bicarbonate; the auxiliary agent is a mixed alcohol; the terminator is TAA; the method used in this example is a suspension method;

[0075] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.25 parts of dispersant, 0.60 parts of initiator, 0.15 parts of pH adjuster, 0.33 parts of auxiliary agent, 75 parts of vinyl chloride, 10 parts of second monomer, and 4.5 parts of third monomer were added into the sealed reactor. The mixture was stirred for 30 minutes. The temperature of the reaction system was raised to 55 °C, and then the reaction was carried out at a constant temperature. When the reaction time reached 1.0 h, the remaining 10.5 parts of third monomer were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry.

[0076] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0077] Example 4

[0078] (1) In terms of weight, prepare 75 parts of vinyl chloride, 15 parts of the second monomer, 10 parts of the third monomer, 0.21 parts of a dispersant, 0.50 parts of an initiator, 160 parts of deionized water, 0.15 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator for use; the second monomer is vinyl acetate; the third monomer is butyl acrylate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 2:1; the initiator is a composite initiator of cumyl peroxide neodecanoate and tert-butyl peroxide neodecanoate; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate; the terminator is TAA; the method used in this example is a suspension method;

[0079] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.21 parts of dispersant, 0.50 parts of initiator, 0.15 parts of pH adjuster, 0.3 parts of auxiliary agent, 75 parts of vinyl chloride, 15 parts of second monomer, and 4 parts of third monomer were added into the sealed reactor. The mixture was stirred for 30 minutes. The temperature of the reaction system was raised to 53 °C, and then the reaction was carried out at a constant temperature. When the reaction time reached 1.5 h, the remaining 6 parts of the third monomer were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry.

[0080] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0081] Example 5

[0082] (1) In terms of weight, prepare 85 parts of vinyl chloride, 5 parts of the second monomer, 10 parts of the third monomer, 0.18 parts of a dispersant, 0.50 parts of an initiator, 160 parts of deionized water, 0.3 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator for use; the second monomer is vinyl acetate; the third monomer is methyl methacrylate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:2; the initiator is azobisisoheptylnitrile; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate; the terminator is TAA; the method used in this example is a suspension method;

[0083] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.3 parts of pH adjuster, 0.3 parts of auxiliary agent, 85 parts of vinyl chloride, 5 parts of second monomer, and 4 parts of third monomer were added into the sealed reactor. The mixture was stirred for 30 minutes. The temperature of the reaction system was raised to 59°C, and then the reaction was carried out at a constant temperature. When the pressure of the reactor dropped by 0.15 MPa, the remaining 6 parts of the third monomer were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry.

[0084] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0085] Example 6

[0086] (1) In terms of weight, 80 parts of vinyl chloride, 10 parts of the second monomer, 10 parts of the third monomer, 0.2 parts of a dispersant, 0.50 parts of an initiator, 160 parts of deionized water, 0.3 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator are prepared for use; the second monomer is vinyl acetate; the third monomer is dibutyl maleate and methyl acrylate, with a weight ratio of 1:1; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:1; the initiator is azobisisoheptylnitrile; the pH regulator is sodium bicarbonate; the auxiliary agent is a mixed alcohol; the terminator is TAA; the method used in this example is a suspension method;

[0087] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.2 parts of dispersant, 0.50 parts of initiator, 0.3 parts of pH adjuster, 0.3 parts of auxiliary agent, 80 parts of vinyl chloride, 10 parts of second monomer, and 5 parts of dibutyl maleate were added into the sealed reactor. Then 2 parts of methyl acrylate were added and stirred for 30 minutes. The temperature of the reaction system was raised to 70 °C and then the reaction was carried out at a constant temperature. When the reaction time reached 1 h, the remaining 3 parts of methyl acrylate were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction and the material was discharged to obtain a slurry.

[0088] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0089] Example 7

[0090] (1) In terms of weight, 85 parts of vinyl chloride, 5 parts of a second monomer, 10 parts of a polymer, 0.18 parts of a dispersant, 0.50 parts of an initiator, 160 parts of deionized water, 0.2 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator are prepared for use; the second monomer is vinyl acetate; the polymer is EVA resin; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:1; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate and hexadecanol in a weight ratio of 1:1; the terminator is TAA; the method used in this example is a suspension method;

[0091] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.2 parts of pH adjuster, 0.3 parts of auxiliary agent, 85 parts of vinyl chloride, 5 parts of second monomer, and 10 parts of polymer were added into the closed reactor. After stirring for 30 minutes, the temperature of the reaction system was raised to 60 °C, and then the reaction was carried out at a constant temperature. When the pressure of the reactor dropped by 0.10 MPa, the remaining 32 parts of vinyl chloride were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry.

[0092] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0093] Example 8

[0094] (1) In terms of weight, prepare 83 parts of vinyl chloride, 5 parts of the second monomer, 5 parts of the third monomer, 7 parts of the polymer, 0.18 parts of the dispersant, 0.50 parts of the initiator, 160 parts of deionized water, 0.25 parts of the pH regulator, 0.3 parts of the auxiliary agent, and 0.15 parts of the terminator for use; the second monomer is vinyl acetate; the third monomer is butyl acrylate; the polymer is EVM elastomer resin; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:2; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agents are sodium dodecylbenzene sulfonate and polyvinyl pyrrolidone; the terminator is TAA; the method used in this example is the suspension method;

[0095] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.25 parts of pH adjuster, 0.3 parts of auxiliary agent, 83 parts of vinyl chloride, 5 parts of second monomer, and 7 parts of polymer were added into the sealed reactor. Then 2 parts of third monomer were added and stirred for 30 minutes. The temperature of the reaction system was raised to 65 °C and then the reaction was carried out at a constant temperature. When the reaction time reached 1.5 h, the remaining 3 parts of third monomer were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.25 MPa. Then, a terminator was added to terminate the reaction and the material was discharged to obtain a slurry.

[0096] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0097] Example 9

[0098] (1) In terms of weight, prepare 80 parts of vinyl chloride, 6.5 parts of the second monomer, 6.5 parts of the third monomer, 7 parts of the polymer, 0.25 parts of the dispersant, 0.50 parts of the initiator, 160 parts of deionized water, 0.28 parts of the pH regulator, 0.3 parts of the auxiliary agent, and 0.15 parts of the terminator for use; the second monomer is tert-butyl vinyl carbonate; the third monomer is methyl acrylate; the polymer is EVM elastomer resin; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 2:1; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agents are sodium dodecylbenzene sulfonate and polyvinyl pyrrolidone; the terminator is TAA; the method used in this example is the suspension method;

[0099] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.25 parts of dispersant, 0.50 parts of initiator, 0.28 parts of pH adjuster, 0.3 parts of auxiliary agent, 80 parts of vinyl chloride, 6.5 parts of second monomer, 7 parts of polymer, and 2.6 parts of third monomer were added into the sealed reactor. The mixture was stirred for 30 minutes. The temperature of the reaction system was raised to 65 °C, and then the reaction was carried out at a constant temperature. When the reaction time reached 1.5 h, the remaining 3.9 parts of the third monomer was continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.20 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry.

[0100] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0101] Example 10

[0102] (1) In terms of weight, prepare 85 parts of vinyl chloride, 5 parts of the second monomer, 10 parts of the third monomer, 0.25 parts of a dispersant, 0.50 parts of an initiator, 160 parts of deionized water, 0.2 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator for use; the second monomer is vinyl acetate; the third monomer is butyl acrylate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 2:1; the initiator is azobisisoheptylnitrile; the pH regulator is sodium bicarbonate; the auxiliary agents are sodium dodecylbenzene sulfonate and polyvinyl pyrrolidone, mixed alcohol; the terminator is TAA; the method used in this example is a microsuspension method;

[0103] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.25 parts of dispersant, 0.50 parts of initiator, 0.2 parts of pH adjuster, 0.3 parts of auxiliary agent, 85 parts of vinyl chloride, 5 parts of second monomer, and 4 parts of third monomer were added into the sealed reactor. The mixture was stirred for 60 minutes. The temperature of the reaction system was raised to 57 °C, and then the reaction was carried out at a constant temperature. When the pressure of the reactor dropped by 0.10 MPa, the remaining 6 parts of the third monomer were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry.

[0104] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0105] Comparative Example 1

[0106] (1) In parts by weight, prepare 100 parts of vinyl chloride, 0.18 parts of dispersant, 0.50 parts of initiator, 160 parts of deionized water, 0.2 parts of pH regulator, 0.3 parts of auxiliary agent, and 0.15 parts of terminator for use; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:1; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate and hexadecanol in a weight ratio of 1:1; the terminator is TAA; the method used in this comparative example is a suspension method;

[0107] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.2 parts of pH adjuster, 0.3 parts of auxiliary agent, and 100 parts of vinyl chloride were added into the sealed reactor. After stirring for 30 minutes, the temperature of the reaction system was raised to 60 °C, and then the reaction was carried out at a constant temperature. The reaction was continued until the pressure of the reactor dropped to 0.30 MPa, and then a terminator was added to terminate the reaction. The material was discharged to obtain a slurry.

[0108] (3) After the slurry is stripped and dehydrated by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain polyvinyl chloride powder.

[0109] Comparative Example 2

[0110] (1) In parts by weight, prepare 85 parts of vinyl chloride, 15 parts of a second monomer, 0.18 parts of a dispersant, 0.50 parts of an initiator, 160 parts of deionized water, 0.2 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator for use; the second monomer is vinyl acetate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:1; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate and hexadecanol in a weight ratio of 1:1; the terminator is TAA; the method used in this comparative example is a suspension method;

[0111] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.2 parts of pH adjuster, 0.3 parts of auxiliary agent, 85 parts of vinyl chloride, and 15 parts of the second monomer were added into the sealed reactor. After stirring for 30 minutes, the temperature of the reaction system was raised to 60 °C, and then the reaction was carried out at a constant temperature until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction, and the material was discharged to obtain a slurry;

[0112] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0113] Comparative Example 3

[0114] (1) In parts by weight, prepare 85 parts of vinyl chloride, 15 parts of a third monomer, 0.18 parts of a dispersant, 0.50 parts of an initiator, 160 parts of deionized water, 0.2 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator for use; the third monomer is butyl acrylate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:1; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate and hexadecanol in a weight ratio of 1:1; the terminator is TAA; the method used in this comparative example is a suspension method;

[0115] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.2 parts of pH adjuster, 0.3 parts of auxiliary agent, 85 parts of vinyl chloride, and 6 parts of the third monomer were added into the sealed reactor. The stirring was continued for 30 minutes. The temperature of the reaction system was raised to 60 °C, and then the reaction was carried out at a constant temperature. When the pressure of the reactor dropped by 0.10 MPa, the remaining 9 parts of the third monomer were continuously added at a constant rate. After the addition was completed, the reaction was continued until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction and the material was discharged.

[0116] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0117] Comparative Example 4

[0118] A vinyl chloride copolymer, the preparation steps are as follows:

[0119] (1) In terms of weight, 85 parts of vinyl chloride, 5 parts of the second monomer, 10 parts of the third monomer, 0.18 parts of the dispersant, 0.50 parts of the initiator, 160 parts of deionized water, 0.2 parts of the pH regulator, 0.3 parts of the auxiliary agent, and 0.15 parts of the terminator are prepared for use; the second monomer is vinyl acetate; the third monomer is butyl acrylate; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:1; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate and hexadecanol in a weight ratio of 1:1; the terminator is TAA; the method used in this example is a suspension method;

[0120] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.2 parts of pH adjuster, 0.3 parts of auxiliary agent, 85 parts of vinyl chloride, 5 parts of second monomer, and 10 parts of third monomer were added into the sealed reactor. The mixture was stirred for 30 minutes. The temperature of the reaction system was raised to 60°C. The reaction was then carried out at a constant temperature until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction. The mixture was discharged to obtain a slurry.

[0121] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0122] Comparative Example 5

[0123] A vinyl chloride copolymer, the preparation steps are as follows:

[0124] (1) In terms of weight, 85 parts of vinyl chloride, 13 parts of a second monomer, 2 parts of a polymer, 0.18 parts of a dispersant, 0.50 parts of an initiator, 160 parts of deionized water, 0.2 parts of a pH regulator, 0.3 parts of an auxiliary agent, and 0.15 parts of a terminator are prepared for use; the second monomer is vinyl acetate; the polymer is EVA resin; the dispersant is a composite dispersant composed of polyvinyl alcohol and hydroxypropyl methylcellulose in a weight ratio of 3:1; the initiator is di(3,5,6-trimethylhexanoyl) peroxide; the pH regulator is sodium bicarbonate; the auxiliary agent is sodium dodecylbenzene sulfonate and hexadecanol in a weight ratio of 1:1; the terminator is TAA (thioacetamide); the method used in this example is a suspension method;

[0125] (2) The reactor was vacuumed and deoxygenated. According to the formula, 160 parts of deionized water, 0.18 parts of dispersant, 0.50 parts of initiator, 0.2 parts of pH adjuster, 0.3 parts of auxiliary agent, 85 parts of vinyl chloride, 13 parts of second monomer, and 2 parts of polymer were added into the closed reactor. The mixture was stirred for 30 minutes. The temperature of the reaction system was raised to 60°C. The reaction was then carried out at a constant temperature until the pressure of the reactor dropped to 0.30 MPa. Then, a terminator was added to terminate the reaction. The mixture was discharged to obtain a slurry.

[0126] (3) After the slurry is subjected to steam stripping treatment and dehydration by a centrifuge, it is sent to an air flow drying tower by a screw conveyor and dried in a cyclone drying tower to obtain vinyl chloride copolymer powder.

[0127] The copolymer powders obtained in Examples 1 to 10 and Comparative Examples 1 to 5 were subjected to glass transition temperature tests, and tensile strength, elongation at break, and plasticizer mobility tests were performed according to the following methods:

[0128] The materials were mixed according to the formula in Table 1, and then mixed on an open mill at 160 °C for 5 min. Finally, the samples were molded into 1 mm specimens on a flat plate molding machine. The molding conditions were divided into three steps:

[0129] Step 1: pressure 20 bar, temperature 160 °C, time 180 s;

[0130] Step 2: pressure 200 bar, temperature 160 °C, time 180 s;

[0131] Step 3: pressure 200 bar, temperature 40 °C, time 360 ​​s.

[0132] Table 1: Basic formula of cable materials

[0133]

[0134] The molded samples were tested for tensile strength, elongation at break and plasticizer migration rate. The tensile strength and elongation at break were tested by a universal tensile testing machine, and the plasticizer migration rate was tested by the following method:

[0135] 1. Cut the molded sample into small pieces of 10 cm × 10 cm and weigh them as m0;

[0136] 2. Place a PE oil absorption specimen block with a length, width and thickness of 20 cm × 20 cm × 0.5 cm above and below the small sample block to absorb the plasticizer that migrates out of the PVC;

[0137] 3. Add a steel plate with a length, width and thickness of 25 cm × 25 cm × 0.15 cm on the top and bottom, and place a 5 kg weight at the center of the surface of the upper steel plate;

[0138] 4. Place the sample together with the weight in a 60 ℃ oven for 24 hours to simulate the precipitation of plasticizer; take out the small sample, wipe the surface of the small sample clean, weigh the weight as m1, and the mobility W is calculated as: W = [(m0-m1) / m0] × 100%.

[0139] The specific test results of the copolymer materials obtained in Examples 1 to 10 and Comparative Examples 1 to 5 are shown in Table 2, Table 3 and Table 4.

[0140] Table 2: Glass transition temperature test results

[0141]

[0142] Table 3: Tensile properties test results

[0143]

[0144] Table 4: Plasticizer migration test results

[0145]

[0146] The above specific embodiments describe the implementation of the present invention in detail, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, the technical solution of the present invention can be modified and changed in many simple ways, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A method for preparing a vinyl chloride copolymer, characterized in that: The method comprises the following steps: uniformly mixing the whole amount of the second monomer, the dispersant, the initiator, the deionized water, the pH regulator, the auxiliary agent, 60%-100% of the amount of vinyl chloride, and 20%-60% of the amount of the third monomer, raising the temperature of the reaction system to 40-70°C to carry out a polymerization reaction, and when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, starting to drop the remaining vinyl chloride and the third monomer, and continuing the reaction after the dropwise addition is completed until the pressure of the reactor drops to 0.20-0.30 MPa, adding a terminator, and discharging the material; The weight ratio of vinyl chloride, the second monomer and the third monomer is (50-90): (5-25): (5-25); The second monomer is selected from one or more vinyl ester monomers; The third monomer is selected from one or more of acrylate monomers, vinyl ether monomers, aromatic vinyl monomers, maleic acid and its anhydride / ester monomers, and vinyl halide monomers.

2. A method for preparing a vinyl chloride copolymer, characterized in that: The method comprises the following steps: uniformly mixing all the formula amounts of the second monomer, dispersant, initiator, deionized water, pH regulator, auxiliary agent, polymer, and 60%-100% formula amount of vinyl chloride, raising the temperature of the reaction system to 40-70°C to carry out polymerization reaction, and when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, starting to drop the remaining vinyl chloride, and continuing the reaction after the dropwise addition is completed until the pressure of the reactor drops to 0.20-0.30 MPa, adding a terminator, and discharging the material; The weight ratio of vinyl chloride, the second monomer and the polymer is (50-90): (5-25): (5-25); The second monomer is selected from one or more vinyl ester monomers; The polymer is a graft copolymerizable polymer; the graft copolymerizable polymer is a resin or elastomer obtained by polymerization of mixed monomers, wherein the mixed monomers are C n H 2n The structure of substituted monoolefins and C n H (2n-2) A mixture of one or more substituted dienes of the same structure.

3. A method for preparing a vinyl chloride copolymer, characterized in that: The method comprises the following steps: uniformly mixing the whole amount of the second monomer, the dispersant, the initiator, the deionized water, the pH regulator, the auxiliary agent, the polymer, 60%-100% of the amount of vinyl chloride, and 20%-60% of the amount of the third monomer, raising the temperature of the reaction system to 40-70°C to carry out a polymerization reaction, and when the pressure of the reactor drops by 0.15-0.25 MPa or the reaction time reaches 1-1.5 h, starting to drop the remaining vinyl chloride and the third monomer, and continuing the reaction after the dropwise addition is completed until the pressure of the reactor drops to 0.20-0.30 MPa, adding a terminator, and discharging the material; The weight ratio of vinyl chloride, the second monomer, the third monomer, and the polymer is (50-90): (5-25): (2-15): (2-15); The second monomer is selected from one or more vinyl ester monomers; The third monomer is selected from one or more of acrylate monomers, vinyl ether monomers, aromatic vinyl monomers, maleic acid and its anhydride / ester monomers, and vinyl halide monomers; The polymer is a graft copolymerizable polymer; the graft copolymerizable polymer is a resin or elastomer obtained by polymerization of mixed monomers, wherein the mixed monomers are C n H 2n The structure of substituted monoolefins and C n H (2n-2) A mixture of one or more substituted dienes of the same structure.

4. A method for preparing a vinyl chloride copolymer according to any one of claims 1 to 3, characterized in that: The vinyl ester monomers include, but are not limited to, vinyl acetate and vinyl versatate.

5. A method for preparing a vinyl chloride copolymer according to any one of claims 1 to 3, characterized in that: The acrylic acid ester monomers include, but are not limited to, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, tert-butyl acrylate, pentyl acrylate, isopentyl acrylate, cyclohexyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, isopentyl methacrylate, ethylhexyl methacrylate, and cyclohexyl methacrylate.

6. A method for preparing a vinyl chloride copolymer according to any one of claims 1 to 3, characterized in that: The maleic acid and its anhydride / ester monomers include but are not limited to diethyl fumarate, dimethyl itaconate, diethyl itaconate, diisopropyl itaconate, and dioctyl itaconate.

7. A method for preparing a vinyl chloride copolymer according to any one of claims 1 to 3, characterized in that: The polymerization reaction is a constant temperature polymerization reaction or a variable temperature polymerization reaction.

8. A method for preparing a vinyl chloride copolymer according to any one of claims 1 to 3, characterized in that: The auxiliary agent includes one or more of a chain regulator, a surfactant, and a water phase inhibitor.

9. A vinyl chloride copolymer, characterized in that: The raw materials include, by weight: 50-90 parts of vinyl chloride, 5-25 parts of a second monomer, 5-25 parts of a third monomer / polymer, 0.15-0.25 parts of a dispersant, 0.46-0.60 parts of an initiator, 150-160 parts of deionized water, 0-0.3 parts of a pH regulator, 0-0.3 parts of an auxiliary agent, and 0.1-0.2 parts of a terminator; Alternatively, the raw materials include, by weight: 50-90 parts of vinyl chloride, 5-25 parts of a second monomer, 2-15 parts of a third monomer, 2-15 parts of a polymer, 0.15-0.25 parts of a dispersant, 0.46-0.60 parts of an initiator, 150-160 parts of deionized water, 0-0.3 parts of a pH regulator, 0-0.3 parts of an auxiliary agent, and 0.1-0.2 parts of a terminator.

10. Use of the vinyl chloride copolymer prepared by the method according to any one of claims 1 to 3 in soft products.

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