Preparation method of polyvinyl chloride paste resin

Abstract

The present invention relates to a polyvinyl chloride paste resin preparation method, which comprises: an emulsion seed production step (S1), controlling reaction conditions, and carrying out a chain reaction by using a vinyl chloride monomer as a raw material to obtain an emulsion seed with a particle size of 0.1-0.15 [mu] m; (S2) an MSP seed production step: controlling reaction conditions, and carrying out a chain reaction by taking a vinyl chloride monomer as a raw material to prepare MSP seeds with the particle size of 0.5-0.55 [mu] m; and (S3) polyvinyl chloride paste resin production: controlling reaction conditions, and carrying out chain reaction by taking the emulsion seeds and the MSP seeds as main raw materials to obtain the polyvinyl chloride paste resin. The particle size of the polyvinyl chloride paste resin is stable and controllable, and the viscosity number distribution interval range is small.

Description

Technical Field

[0001] The invention relates to the technical field of production of polyvinyl chloride paste resin, in particular to a preparation method of polyvinyl chloride paste resin. Background Art

[0002] Polyvinyl chloride (PVC) paste resin refers to this type of resin that is mainly used in the form of a paste, also known as plasticized paste. It has the characteristics of stable performance, easy control, easy use, excellent product performance, and good chemical stability. It is widely used in the production of artificial leather, vinyl toys, wallpaper, paints and coatings, foamed plastics, etc.

[0003] Polyvinyl chloride (PVC) paste resin is usually prepared by emulsion method and microsuspension method. The formula of emulsion method adopts vinyl chloride monomer, water, water-soluble initiator (water-soluble persulfate) and emulsifier, etc. The initiation is carried out in the water phase. In the emulsion polymerization, if there is a high polymer latex that has been generated, by controlling the material ratio and conditions, in principle, the vinyl chloride monomer will only polymerize on the latex particles that have been generated, and no new particles will be formed. This high polymer latex that has been generated is like a seed crystal, so it is called "emulsion seed polymerization".

[0004] The micro-suspension method is to first use mechanical homogenization to make part of the vinyl chloride monomer into a stable emulsion, and then select an oil-soluble initiator for polymerization. The PVC paste resin produced by this method has excellent fluidity, a small amount of emulsifier, and good thermal stability and water resistance of the resin.

[0005] However, the size of the paste polyvinyl chloride particles produced by the existing method is uncontrollable, and the viscosity distribution range is wide (usually the range is ≥15), resulting in poor performance of the polyvinyl chloride paste resin, which is not conducive to downstream fine classification processing.

[0006] The invention aims to solve the problem that the particle size of polyvinyl chloride paste resin produced by the existing method is uncontrollable and the viscosity number distribution range is wide and unstable. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a method for preparing a polyvinyl chloride paste resin, comprising an emulsion seed production step S1, adding 10000-15000 parts of hot desalted water, 5-15 parts of 32% liquid caustic soda, 0.2-0.4 parts of ferrous sulfate, 2-4 parts of sodium formaldehyde sulfoxylate, 0.5-2 parts of ethylenediaminetetraacetic acid, 40-75 parts of potassium laurate, and 5000-10000 parts of vinyl chloride monomer into a reactor, controlling the temperature to 55±0.5°C and the pressure to 700-850Kpa, and carrying out a chain reaction, adding 1-2.5 parts of potassium persulfate and 300-400 parts of sodium alkylbenzene sulfonate during the reaction, and obtaining an emulsion seed with a particle size of 0.1-0.15um after the reaction is completed.

[0008] MSP seed production step S2, add 1000-15000 parts of desalted water, 5-15 parts of 32% liquid alkali, 100-200 parts of dodecyl peroxide powder, 5-15 parts of potassium dihydrogen phosphate powder, 5000-10000 parts of vinyl chloride monomer, 100-200 parts of sodium alkylbenzene sulfonate, 50-200 parts of defoaming agent into the reactor, control the temperature to 42.5±0.5°C, the pressure to 500-650Kpa, carry out a chain reaction, and obtain MSP seeds with a particle size of 0.5-0.55um after the reaction.

[0009] The polyvinyl chloride paste resin production step S3 uses emulsion seeds and MSP seeds as main raw materials to produce polyvinyl chloride paste resin, wherein when producing polyvinyl chloride paste resin with a viscosity of 120-135, the polyvinyl chloride paste resin production step S3 comprises adding 1-4 parts of emulsion seeds (dry basis), 2-5 parts of MSP seeds (dry basis), 20000-35000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate, 0.1-0.3 parts of copper sulfate (dry basis), 11500-2 5000 parts, control the temperature at 49-56℃, the pressure at 700-850Kpa, and carry out chain reaction. After the reaction starts, add 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate (dry basis), 50-100 parts of sodium lauryl polyoxyethylene ether sulfate (dry basis), 1.5-5.5 parts of vitamin C acid, and 50-100 parts of defoaming agent. After the reaction is completed, a polyvinyl chloride paste resin with a viscosity between 120 and 135 is obtained.

[0010] Preferably, when producing a polyvinyl chloride paste resin with a high foaming performance and a viscosity of 105-120, the polyvinyl chloride paste resin production step S3 includes adding 1-3 parts of emulsion seeds (dry basis), 2-4 parts of MSP seeds (dry basis), 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-0.3 parts of copper sulfate (dry basis), and 11,500-25,000 parts of vinyl chloride monomer to the reaction kettle, and controlling the temperature at 49-56°C. , pressure 700-850Kpa, chain reaction, after the reaction starts, add 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium dodecyl sulfate (dry basis), 40-100 parts of sodium lauryl polyoxyethylene ether sulfate (dry basis), 1.5-5.5 parts of potassium metabisulfite, 50-100 parts of defoamer, the reaction is completed, and a polyvinyl chloride paste resin with a viscosity of 105-120 and high foaming performance is obtained.

[0011] Preferably, when producing a polyvinyl chloride paste resin with a viscosity of 105-120 and low foaming performance, the polyvinyl chloride paste resin production step S3 comprises adding 1-3 parts (dry basis) of emulsion seeds, 2-4 parts of MSP seeds (dry basis), 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-0.3 parts of copper sulfate (dry basis), and 11,500-25,000 parts of vinyl chloride monomer into a reaction kettle, controlling the temperature at 49 -56℃, pressure 700-850Kpa, chain reaction, after the reaction starts, add 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate (dry basis), 50-100 parts of potassium laurate (dry basis), 5-10 parts of vitamin C acid, 50-100 parts of defoamer, the reaction is completed, and a low foaming polyvinyl chloride paste resin with a viscosity between 105-120 is obtained.

[0012] Preferably, when producing a polyvinyl chloride paste resin with a high degree of polymerization and a viscosity of 150-165, the polyvinyl chloride paste resin production step S3 comprises adding 1-3 parts of emulsion seeds (dry basis), 2-4 parts of MSP seeds (dry basis), 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-1 parts of copper sulfate (dry basis), 1-1.5 parts of potassium persulfate (dry basis), 11,500-25,000 parts of vinyl chloride monomer, and 10-20 parts of dipropylene phthalate into a reaction kettle. 20 parts, control the temperature at 49-56℃, the pressure at 700-850Kpa, and carry out chain reaction. After the reaction starts, add 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate (dry basis), 40-100 parts of sodium lauryl polyoxyethylene ether sulfate (dry basis), 3.5-10 parts of vitamin C acid, and 50-100 parts of defoaming agent. After the reaction is completed, a polyvinyl chloride paste resin with a high degree of polymerization and a viscosity between 150-165 is obtained.

[0013] Preferably, when producing a polyvinyl chloride paste resin with a high degree of polymerization and a viscosity greater than 165, the polyvinyl chloride paste resin production step S3 comprises adding 1-3 parts of emulsion seeds (dry basis), 2-4 parts of MSP seeds (dry basis), 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-1 parts of copper sulfate (dry basis), 1-1.5 parts of potassium persulfate (dry basis), 11,500-25,000 parts of vinyl chloride monomer, and 20-30 parts of dipropylene phthalate into the reaction kettle. 50 parts, control the temperature at 49-56°C and the pressure at 700-850Kpa to carry out a chain reaction. After the reaction starts, add 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate (dry basis), 40-100 parts of sodium lauryl polyoxyethylene ether sulfate (dry basis), 3.5-10 parts of vitamin C acid and 50-100 parts of defoaming agent. After the reaction is completed, a high-polymerization degree and high-strength polyvinyl chloride paste resin with a viscosity greater than 165 is obtained.

[0014] Preferably, in the polyvinyl chloride paste resin production step S3, when the temperature in the reactor reaches 4°C below the set temperature, vitamin C acid or potassium metabisulfite is added according to the severity of the reaction.

[0015] Preferably, in the polyvinyl chloride paste resin production step S3, vinyl chloride monomer is added 1 minute after the start of the chain reaction, wherein, during the period when the cumulative amount of vinyl chloride monomer added is 0-(10000-20000) parts, it is added at a flow rate of 25000-45000 parts / h, and the remaining vinyl chloride monomer is added at a flow rate of 5000-5500 parts / h.

[0016] Preferably, in the polyvinyl chloride paste resin production step S3, sodium alkylbenzene sulfonate or sodium dodecyl sulfate, and sodium lauryl polyoxyethylene ether sulfate or potassium laurate are added 5 minutes after the start of the chain reaction.

[0017] Preferably, in the emulsion seed production step S1, the reaction ends when the pressure in the reactor drops to 110-350 KPa. In the MSP seed production step S2, the reaction ends when the pressure in the reactor drops to 110-350 KPa. In the polyvinyl chloride paste resin production step S3, the reaction ends when the pressure in the reactor drops to 350-550 KPa.

[0018] The present invention first produces emulsion seeds and MSP seeds, and then adds the two seeds into the reactor, and increases the adaptability of the reaction process to environmental changes by precisely controlling the temperature and the addition of raw materials and auxiliary materials, so that the reaction process is stable and the reaction exothermic process is orderly, thereby effectively controlling the reaction process of paste resin production, so that it continues to grow to form a bimodal distribution of polyvinyl chloride paste resin, so that the particle size of the polyvinyl chloride paste resin is stable and controllable, and at the same time, the viscosity of the polyvinyl chloride paste resin is controlled within a relatively certain numerical range and a smaller deviation range. Various performance indicators of the paste resin produced by this method are better than those of the paste resin produced by other processes, the product particle size is stable, the viscosity range is small, and it is conducive to processing in downstream subdivided fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 .Flow chart of the preparation method of polyvinyl chloride paste resin. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, the preparation method of polyvinyl chloride paste resin includes an emulsion seed production step S1, adding 10000-15000 parts of hot desalted water, 5-15 parts of 32% liquid caustic soda, 0.2-0.4 parts of ferrous sulfate, 2-4 parts of sodium formaldehyde sulfoxylate, 0.5-2 parts of ethylenediaminetetraacetic acid, 40-75 parts of potassium laurate, and 5000-10000 parts of vinyl chloride monomer into a reaction kettle.

[0022] The temperature is controlled at 55±0.5°C and the pressure is 700-850Kpa to carry out a chain reaction. During the reaction, 1-2.5 parts of potassium persulfate and 300-400 parts of sodium alkylbenzene sulfonate are continuously added. After the reaction, emulsion seeds with a particle size of 0.1-0.15um are obtained.

[0023] During the reaction, part of the vinyl chloride monomer is dispersed into droplets, and potassium laurate is adsorbed on the surface of the droplets to form solubilized micelles. Ferrous sulfate, sodium formaldehyde sulfoxylate and potassium persulfate form a redox system, and potassium persulfate undergoes a redox reaction to produce free radicals, which trigger the polymerization of vinyl chloride in the solubilized micelles. The micelles gradually become larger until the free radicals are consumed, and finally form an emulsion seed with a particle size of about 0.1-0.15 microns.

[0024] The reaction is terminated when the pressure in the reactor drops to 110-350Kpa. Since the polymerization reaction of polyvinyl chloride paste resin is an exothermic reaction, the pressure in the polymerization reactor is equivalent to the saturated vapor pressure of vinyl chloride. At the beginning of the reaction, there is only vinyl chloride monomer phase in the system. As the polymerization reaction proceeds, it gradually changes to two phases of vinyl chloride monomer phase and polyvinyl chloride paste resin. In the late stage of the polymerization reaction, the vinyl chloride monomer phase is gradually consumed to about 10% remaining, the liquid phase vinyl chloride monomer gradually disappears, and the saturated vapor pressure in the polymerization reactor begins to gradually decrease. At the end of the final reaction, the pressure drops to 110-350Kpa.

[0025] MSP seed production step S2, add 1000-15000 parts of desalted water, 5-15 parts of 32% liquid caustic soda, 100-200 parts of dodecyl peroxide powder, 5-15 parts of potassium dihydrogen phosphate powder, 5000-10000 parts of vinyl chloride monomer, 100-200 parts of sodium alkylbenzene sulfonate, and 50-200 parts of defoaming agent into the reactor. Control the temperature to 42.5±0.5℃ and the pressure to 500-650Kpa to carry out a chain reaction. When the pressure in the reactor drops to 110-350Kpa, the reaction ends and MSP seeds with a particle size of 0.5-0.55um are obtained.

[0026] MSP seed micro-suspension polymerization is a polymerization reaction initiated by an oil-soluble initiator in fine vinyl chloride monomer droplets dispersed and stabilized by an emulsifier. Dodecyl peroxide is fully dissolved in vinyl chloride by stirring, and the vinyl chloride dissolved with dodecyl peroxide is dispersed in the water phase to form droplets under the action of sodium alkylbenzene sulfonate. Dodecyl peroxide in the droplets is decomposed by heat to produce free radicals, which initiate the polymerization reaction of vinyl chloride monomer. The droplets are gradually enlarged until the vinyl chloride monomer in the droplets is consumed, and finally MSP seeds of about 0.5-0.55 microns containing a certain amount of initiator are formed.

[0027] The polyvinyl chloride paste resin production step S3 is to produce polyvinyl chloride paste resin using the emulsion seeds and MSP seeds as main raw materials.

[0028] When producing a polyvinyl chloride paste resin with a viscosity of 120-135, the polyvinyl chloride paste resin production step S3 includes adding 1-4 parts of emulsion seeds (dry basis), 2-5 parts of MSP seeds (dry basis), 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-0.3 parts of copper sulfate (dry basis), and 11,500-25,000 parts of vinyl chloride monomer into a reaction kettle, controlling the temperature to 49-56°C and the pressure to 700-850°C. Kpa, chain reaction, after the reaction starts, continuously add 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate, 50-100 parts of sodium lauryl polyoxyethylene ether sulfate (dry basis), 1.5-5.5 parts of vitamin C acid, 50-100 parts of defoaming agent, when the pressure in the reactor drops to 350-550Kpa, the reaction ends, and a polyvinyl chloride paste resin with a viscosity between 120-135 is obtained.

[0029] When producing polyvinyl chloride paste resin with a viscosity of 105-120, the polyvinyl chloride paste resin production step S3 includes adding 1-3 parts of emulsion seeds (dry basis), 2-4 parts of MSP seeds (dry basis), 20000-35000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-0.3 parts of copper sulfate (dry basis), and 11500-25000 parts of vinyl chloride monomer into a reaction kettle, controlling the temperature at 49-56°C and the pressure at 700-850Kpa, and performing chain reaction. Reaction. After the reaction starts, 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium dodecyl sulfate (dry basis), 40-100 parts of sodium lauryl polyoxyethylene ether sulfate (dry basis), 1.5-5.5 parts of potassium metabisulfite and 50-100 parts of defoaming agent are continuously added. When the pressure in the reactor drops to 350-550Kpa, the reaction is terminated to obtain a polyvinyl chloride paste resin with a viscosity of 105-120 and high foaming performance.

[0030] When producing polyvinyl chloride paste resin with a viscosity of 105-120, the polyvinyl chloride paste resin production step S3 includes adding 1-3 parts of emulsion seeds (dry basis), 2-4 parts of MSP seeds (dry basis), 20000-35000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-0.3 parts of copper sulfate (dry basis), and 11500-25000 parts of vinyl chloride monomer into the reaction kettle, controlling the temperature at 49-56°C and the pressure at 700-850Kpa. , a chain reaction is carried out. After the reaction starts, 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate (dry basis), 50-100 parts of potassium laurate (dry basis), 5-10 parts of vitamin C acid, and 50-100 parts of defoaming agent are added continuously. When the pressure in the reactor drops to 350-550Kpa, the reaction is completed to obtain a polyvinyl chloride paste resin with a viscosity between 105-120 and low foaming performance.

[0031] When producing a polyvinyl chloride paste resin with a viscosity of 150-165, the polyvinyl chloride paste resin production step S3 includes adding 1-3 parts of emulsion seeds (dry basis), 2-4 parts of MSP seeds (dry basis), 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-1 parts of copper sulfate (dry basis), 1-1.5 parts of potassium persulfate (dry basis), 11,500-25,000 parts of vinyl chloride monomer, and 10-20 parts of dipropylene phthalate into a reaction kettle, controlling the temperature at 49-56°C, and pressing The pressure is 700-850Kpa to carry out a chain reaction. After the reaction starts, 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate (dry basis), 40-100 parts of sodium lauryl polyoxyethylene ether sulfate (dry basis), 3.5-10 parts of vitamin C acid and 50-100 parts of defoaming agent are added continuously. When the pressure in the reactor drops to 350-550Kpa, the reaction is terminated to obtain a polyvinyl chloride paste resin with a high degree of polymerization and a viscosity between 150-165.

[0032] When producing polyvinyl chloride paste resin with a viscosity greater than 165, the polyvinyl chloride paste resin production step S3 includes adding 1-3 parts of emulsion seeds (dry basis), 2-4 parts of MSP seeds (dry basis), 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate (dry basis), 0.1-1 parts of copper sulfate (dry basis), 1-1.5 parts of potassium persulfate (dry basis), 11,500-25,000 parts of vinyl chloride monomer, and 20-50 parts of dipropylene phthalate into the reaction kettle, controlling the temperature to 49-56°C and the pressure to 50°C. 700-850Kpa, chain reaction, after the reaction starts, continuously add 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate (dry basis), 40-100 parts of sodium lauryl polyoxyethylene ether sulfate (dry basis), 3.5-10 parts of vitamin C acid, 50-100 parts of defoaming agent, when the pressure in the reactor drops to 350-550Kpa, the reaction is finished, and a high-polymerization degree and high-strength polyvinyl chloride paste resin with a viscosity of more than 165 is obtained.

[0033] In the polyvinyl chloride paste resin production step S3, when the temperature in the reactor reaches 4°C below the set temperature, vitamin C acid or potassium metabisulfite is continuously added according to the intensity of the reaction.

[0034] In the polyvinyl chloride paste resin production step S3, vinyl chloride monomer is continuously added 1 minute after the chain reaction starts, wherein, during the period when the cumulative amount of vinyl chloride monomer added is 0-(10000-20000) parts, it is added at a flow rate of 25000-45000 parts / h, and the remaining vinyl chloride monomer is added at a flow rate of 5000-5500 parts / h.

[0035] In the polyvinyl chloride paste resin production step S3, 5 minutes after the chain reaction starts, sodium alkylbenzene sulfonate or sodium dodecyl sulfate, and sodium lauryl polyoxyethylene ether sulfate or potassium laurate are added continuously.

[0036] The role of the mixed emulsifier is to coat the surface of the MSP seeds and emulsion seeds to prevent the vinyl chloride monomer from forming new particles outside the seeds, thereby maintaining the stability of the system. Since the MSP seeds and emulsion seeds formed in the early stage have a certain amount of emulsifier coating on the surface at the end of the polymerization, as the reaction proceeds, the emulsifier on the surface of the seeds is consumed and needs to be continuously replenished. Therefore, it is necessary to continuously add the mixed emulsifier according to the reaction speed, and the added flow rate is set according to the reaction situation. For example, it is added at a set value of 260-300kg / h in the early and middle stages of the reaction, and added at a rate of 400-450kg / h in the late stage of the reaction.

[0037] There are two main types of particle morphology of polyvinyl chloride paste resin, primary particle type and secondary particle type. Primary particles are formed during the polymerization process, and secondary particles are formed during the spray drying process. When the primary particles present a continuous, single-peak narrow particle distribution, the plastisol (a stable dispersion formed by mixing polyvinyl chloride paste resin with plasticizer and stirring, a unique liquid form of paste resin in the unprocessed state) has a large viscosity, which is not conducive to downstream processing and production.

[0038] When the primary particles have a bimodal particle distribution, due to the mutual filling effect between large and small resin particles, the amount of plasticizer filling between resin particles is reduced, while the amount of plasticizer that can flow freely will increase. Therefore, the plastic paste has a smaller viscosity, which is conducive to the processing of paste resin.

[0039] The following is explained by way of examples.

[0040] Example 1 Add 12000kg of hot desalted water, 5kg of 32% liquid caustic soda, 0.4kg of ferrous sulfate, 3.5kg of sodium formaldehyde sulfoxylate, 1.5kg of ethylenediaminetetraacetic acid, 65kg of potassium laurate and 9000kg of vinyl chloride monomer into the reactor, and carry out a chain reaction at a temperature of 55±0.5℃ and a pressure of 700-850 Kpa. During the reaction, 1kg of potassium persulfate (dry basis) and 340kg of sodium alkylbenzene sulfonate (dry basis) are continuously added. After the reaction is completed, an emulsion seed with a particle size of 0.1-0.15um is obtained.

[0041] Add 10,000 kg of desalted water, 5 kg of 32% liquid caustic soda, 150 kg of dodecyl peroxide powder, 10 kg of potassium dihydrogen phosphate powder, 6,000 kg of vinyl chloride monomer, 115 kg of sodium alkylbenzene sulfonate (dry basis), and 50 kg of defoaming agent into the reactor, control the temperature at 42.5±0.5°C and the pressure at 500-650 Kpa to carry out a chain reaction, and obtain MSP seeds with a particle size of 0.5-0.55 um after the reaction.

[0042] Add 1.5kg of emulsion seeds (dry basis), 3.5kg of MSP seeds (dry basis), 28000kg of hot desalted water, 10kg of potassium dihydrogen phosphate, 0.2kg of copper sulfate, and 13000kg of vinyl chloride monomer into the reactor, control the temperature at 53±0.5℃, and the pressure at 700-850Kpa to carry out a chain reaction. During the reaction, continuously add a mixed solution of 1.5kg of vitamin C acid, 15000kg of vinyl chloride monomer, 3kg of 32% liquid alkali, 250kg of sodium alkylbenzene sulfonate, 70kg of sodium lauryl polyoxyethylene ether sulfate, and 80kg of defoaming agent. After the reaction, a paste-like polyvinyl chloride resin with a viscosity of 125-130 and a paste viscosity of 3.5-5 is obtained.

[0043] Example 2 15000 kg of hot desalted water, 15 kg of 32% liquid caustic soda, 0.4 kg of ferrous sulfate, 4 kg of sodium formaldehyde sulfoxylate, 2 kg of ethylenediaminetetraacetic acid, 75 kg of potassium laurate and 10000 kg of vinyl chloride monomer were added into the reactor. A chain reaction was carried out at a temperature of 55°C and a pressure of 850 KPa. During the reaction, 2.5 kg of potassium persulfate and 2000 kg of sodium alkylbenzene sulfonate were continuously added until the reaction was completed to obtain emulsion seeds with a particle size of 0.1-0.15 um.

[0044] Add 15000 kg of desalted water, 15 kg of 32% liquid caustic soda, 200 kg of dodecyl peroxide powder, 15 kg of potassium dihydrogen phosphate powder, 10000 kg of vinyl chloride monomer, 500 kg of sodium alkylbenzene sulfonate, and 200 kg of defoaming agent into the reactor, control the temperature at 42.5°C and the pressure at 650 KPa to carry out a chain reaction, and obtain MSP seeds with a particle size of 0.5-0.55 um after the reaction.

[0045] Add 1.6kg of emulsion seeds (dry basis), 2.9kg of MSP seeds (dry basis), 30,000kg of hot desalted water, 15kg of potassium dihydrogen phosphate (dry basis), 0.2kg of copper sulfate (dry basis), and 18,500kg of vinyl chloride monomer into the reactor, control the temperature at 56°C and the pressure at 850Kpa to carry out a chain reaction. During the reaction, continuously add 21,000kg of vinyl chloride monomer and 12kg of 32% liquid alkali, 300kg of sodium dodecyl sulfate (dry basis), 50kg of sodium lauryl polyoxyethylene ether sulfate (dry basis), 4kg of biased potassium sulfate, and 80kg of defoaming agent. After the reaction is completed, a paste-like polyvinyl chloride resin with a viscosity number of 110-115 and a paste viscosity of 3.0-4.0 and high foaming performance is obtained.

[0046] Example 3 Add 12000kg of hot desalted water, 10kg of 32% liquid caustic soda, 0.3kg of ferrous sulfate, 3kg of sodium formaldehyde sulfoxylate, 1kg of ethylenediaminetetraacetic acid, 50kg of potassium laurate and 8000kg of fresh vinyl chloride monomer into the reactor, and carry out a chain reaction at a temperature of 55°C and a pressure of 800Kpa. During the reaction, continuously add 1.5kg of potassium persulfate and 1500kg of sodium alkylbenzene sulfonate until the reaction is completed, and obtain emulsion seeds with a particle size of 0.1-0.15um.

[0047] Add 12000 kg of desalted water, 10 kg of 32% liquid caustic soda, 150 kg of dodecyl peroxide powder, 10 kg of potassium dihydrogen phosphate powder, 8000 kg of vinyl chloride monomer, 300 kg of sodium alkylbenzene sulfonate, and 100 kg of defoaming agent into the reactor, control the temperature at 42.5 ° C and the pressure at 600 Kpa to carry out a chain reaction, and obtain MSP seeds with a particle size of 0.5-0.55 um after the reaction.

[0048] Add 2.1kg of emulsion seeds (dry basis), 2.7kg of MSP seeds (dry basis), 28000kg of hot desalted water, 8kg of potassium dihydrogen phosphate, 0.2kg of copper sulfate, 3000kg of vinyl chloride monomer and 12000kg of vinyl chloride monomer into the reactor, control the temperature at 55.5℃ and the pressure at 800Kpa to carry out a chain reaction. During the reaction, continuously add 21000kg of fresh vinyl chloride monomer and 7kg of 32% liquid alkali, 295kg of sodium alkylbenzene sulfonate (dry basis), 70kg of sodium lauryl polyoxyethylene ether sulfate (dry basis), 6kg of vitamin C acid (dry basis) and 80kg of defoaming agent. After the reaction is completed, a paste-like polyvinyl chloride resin with low foaming performance having a viscosity number of 115-120 and a paste viscosity of 3.0-4.0 is obtained.

[0049] Example 4 Add 13000 kg of hot desalted water, 12 kg of 32% liquid caustic soda, 0.2 kg of ferrous sulfate, 2 kg of sodium formaldehyde sulfoxylate, 1 kg of ethylenediaminetetraacetic acid, 50 kg of potassium laurate and 5000 kg of fresh vinyl chloride monomer into the reactor, and carry out a chain reaction at a temperature of 55°C and a pressure of 700 KPa. During the reaction, 1 kg of potassium persulfate and 1000 kg of sodium alkylbenzene sulfonate are continuously added until the reaction is completed to obtain emulsion seeds with a particle size of 0.1-0.15 um.

[0050] Add 13000 kg of desalted water, 12 kg of 32% liquid caustic soda, 150 kg of dodecyl peroxide powder, 10 kg of potassium dihydrogen phosphate powder, 8000 kg of fresh vinyl chloride monomer, 300 kg of sodium alkylbenzene sulfonate, and 100 kg of defoaming agent into the reactor, control the temperature at 42.5 ° C and the pressure at 500 Kpa to carry out a chain reaction, and obtain MSP seeds with a particle size of 0.5-0.55 um after the reaction.

[0051] Add 2.4 kg of emulsion seeds (dry basis), 3.9 kg of MSP seeds (dry basis), 28,000 kg of hot desalted water, 8 kg of potassium dihydrogen phosphate, 0.75 kg of copper sulfate, 3,000 kg of recovered vinyl chloride monomer, 12,000 kg of fresh vinyl chloride monomer, 1.2 kg of potassium persulfate (dry basis), and 18 kg of dipropylene phthalate into the reactor, control the temperature at 49°C and the pressure at 850 KPa to carry out a chain reaction. During the reaction, continuously add 21,000 kg of fresh vinyl chloride monomer and 10 kg of 32% liquid alkali, 260 kg of sodium alkylbenzene sulfonate (dry basis), 50 kg of sodium lauryl polyoxyethylene ether sulfate (dry basis), 6 kg of vitamin C acid (dry basis), and 80 kg of defoaming agent. After the reaction is completed, a paste-like polyvinyl chloride resin with a high degree of polymerization and a viscosity number of 155-165 and a paste viscosity of 2.5-3.5 is obtained.

[0052] Example 5 14000kg of hot desalted water, 8kg of 32% liquid caustic soda, 0.3kg of ferrous sulfate, 4kg of sodium formaldehyde sulfoxylate, 1.5kg of ethylenediaminetetraacetic acid, 60kg of potassium laurate and 9000kg of vinyl chloride monomer were added into the reactor. A chain reaction was carried out at a temperature of 55°C and a pressure of 850Kpa. During the reaction, 2kg of potassium persulfate and 1800kg of sodium alkylbenzene sulfonate were continuously added until the reaction was completed to obtain emulsion seeds with a particle size of 0.1-0.15um.

[0053] Add 15000 kg of desalted water, 15 kg of 32% liquid caustic soda, 200 kg of dodecyl peroxide powder, 15 kg of potassium dihydrogen phosphate powder, 9000 kg of fresh vinyl chloride monomer, 400 kg of sodium alkylbenzene sulfonate, and 100 kg of defoaming agent into the reactor, control the temperature at 42.5°C and the pressure at 650 KPa to carry out a chain reaction, and obtain MSP seeds with a particle size of 0.5-0.55 um after the reaction.

[0054] Add 2.3kg of emulsion seeds (dry basis), 3.7kg of MSP seeds (dry basis), 26000kg of hot desalted water, 8kg of potassium dihydrogen phosphate, 0.7kg of copper sulfate, 4000kg of vinyl chloride monomer, 11000kg of vinyl chloride monomer, 1.2kg of potassium persulfate (dry basis), 28kg of dipropylene phthalate into the reactor, control the temperature at 49°C and the pressure at 850Kpa to carry out a chain reaction. During the reaction, continuously add 21000kg of fresh vinyl chloride monomer and 8kg of 32% liquid alkali, 260kg of sodium alkylbenzene sulfonate (dry basis), 50kg of sodium lauryl polyoxyethylene ether sulfate (dry basis), 6kg of vitamin C acid (dry basis), and 80kg of defoaming agent. After the reaction is completed, a high-polymerization and high-strength paste-like polyvinyl chloride resin with a viscosity number of 180-185 and a paste viscosity of 3.0-4.0 is obtained.

[0055] In each step of Example 1, the temperature for the chain reaction is controlled with an error of ±0.5°C. The reaction temperatures in other examples have no error and the final reaction effects are the same, indicating that an error of ±0.5°C in the reaction temperature can be allowed during the reaction.

[0056] The properties of the polyvinyl chloride paste resins prepared in Examples 1 to 5 were tested in sequence, and the following test results were obtained.

[0057] Table 1 Performance of polyvinyl chloride paste resin in various examples Example Viscosity range (ml / g) Paste viscosity (Pa.s) Number of impurity particles 250um sieve hole sieve residue mass fraction (%) Volatile matter mass fraction (%) 63um sieve hole sieve residue mass fraction / % Whiteness (160℃, 10min) / % Scraper fineness (um) Vinyl chloride monomer content (ug / g) 1 125-130 3.5-5.0 ≤12 ≤0.4 ≤0.1 ≤1 ≥80 ≤100 ≤5 2 110-115 3.0-4.0 ≤12 ≤0.4 ≤0.1 ≤1 ≥80 ≤100 ≤5 3 115-120 3.0-4.0 ≤12 ≤0.4 ≤0.1 ≤1 ≥80 ≤100 ≤5 4 155-165 2.5-3.5 ≤12 ≤0.4 ≤0.1 ≤1 ≥80 ≤100 ≤5 5 180-185 3.0-4.0 ≤12 ≤0.4 ≤0.1 ≤1 ≥80 ≤100 ≤5 It can be seen from the above table that in Examples 1 to 5, the viscosity range of the polyvinyl chloride paste resin produced by the method of the present invention is less than 5, the paste viscosity range is less than 1.5, the number of impurity particles is less than or equal to 12, the mass fraction of the 63um sieve residue is less than or equal to 1%, and the mass fraction of the 250um sieve residue is less than or equal to 0.4%.

[0058] In summary, the present invention first produces emulsion seeds and MSP seeds, and then adds the two seeds to the reactor, and through precise control of temperature and continuous addition of raw materials and auxiliary materials, increases the adaptability of the reaction process to environmental changes, makes the reaction process stable, and the reaction exothermic process orderly, thereby effectively controlling the reaction process of paste resin production, making it grow continuously to form a bimodal distribution of polyvinyl chloride paste resin, making the particle size of polyvinyl chloride paste resin stable and controllable, and controlling the viscosity of polyvinyl chloride paste resin within a relatively certain numerical range and a smaller deviation range. The various performance indicators of the paste resin produced by this method are better than those of the paste resin produced by other processes, the product particle size is stable, and the viscosity range is small, which is conducive to processing in downstream subdivisions.

[0059] It should be noted that the above embodiments are intended to illustrate the present invention rather than to limit the present invention.

Claims

1. A method for preparing a polyvinyl chloride paste resin, characterized in that: include, The emulsion seed production step (S1) is to add 10000-15000 parts of hot desalted water, 5-15 parts of 32% liquid caustic soda, 0.2-0.4 parts of ferrous sulfate, 2-4 parts of sodium formaldehyde sulfoxylate, 0.5-2 parts of ethylenediaminetetraacetic acid, 40-75 parts of potassium laurate, and 5000-10000 parts of vinyl chloride monomer into a reaction kettle, and control the temperature to 55±0.5°C and the pressure to 700-850Kpa to carry out a chain reaction, and add 1-2.5 parts of potassium persulfate and 300-400 parts of sodium alkylbenzene sulfonate during the reaction, and obtain emulsion seeds with a particle size of 0.1-0.15um after the reaction is completed; MSP seed production step (S2), adding 1000-15000 parts of desalted water, 5-15 parts of 32% liquid caustic soda, 100-200 parts of dodecyl peroxide powder, 5-15 parts of potassium dihydrogen phosphate powder, 5000-10000 parts of vinyl chloride monomer, 100-200 parts of sodium alkylbenzene sulfonate, and 50-200 parts of defoaming agent into a reactor, controlling the temperature to 42.5±0.5°C and the pressure to 500-650Kpa, to carry out a chain reaction, and after the reaction, obtaining MSP seeds with a particle size of 0.5-0.55um; The polyvinyl chloride paste resin production step (S3) uses the emulsion seeds and MSP seeds as main raw materials to produce polyvinyl chloride paste resin. Wherein, when producing a polyvinyl chloride paste resin with a viscosity of 120-135, the polyvinyl chloride paste resin production step (S3) includes adding 1-4 parts of emulsion seeds, 2-5 parts of MSP seeds, 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate, 0.1-0.3 parts of copper sulfate, and 11,500-25,000 parts of vinyl chloride monomer into a reaction kettle, controlling the temperature to 49-56° C. and the pressure to 700-850 KPa to carry out a chain reaction, and after the reaction starts, adding 15,000-25,000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid caustic soda, 200-350 parts of sodium alkylbenzene sulfonate, 50-100 parts of sodium lauryl polyoxyethylene ether sulfate, 1.5-5.5 parts of vitamin C acid, and 50-100 parts of a defoaming agent, and ending the reaction to obtain a polyvinyl chloride paste resin with a viscosity of 120-135.

2. The method for preparing a polyvinyl chloride paste resin according to claim 1, characterized in that: When producing a polyvinyl chloride paste resin with a viscosity of 105-120 and high foaming performance, the polyvinyl chloride paste resin production step (S3) includes adding 1-3 parts of emulsion seeds, 2-4 parts of MSP seeds, 20000-35000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate, 0.1-0.3 parts of copper sulfate, and 11500-25000 parts of vinyl chloride monomer into a reaction kettle, controlling the temperature to 49-56° C. and the pressure to 700-850 KPa to carry out a chain reaction, and after the reaction starts, adding 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid caustic soda, 200-350 parts of sodium dodecyl sulfate, 40-100 parts of sodium lauryl polyoxyethylene ether sulfate, 1.5-5.5 parts of potassium metabisulfite, and 50-100 parts of a defoaming agent, and completing the reaction to obtain a polyvinyl chloride paste resin with a viscosity of 105-120 and high foaming performance.

3. The method for preparing a polyvinyl chloride paste resin according to claim 1, characterized in that: When producing a polyvinyl chloride paste resin with a viscosity of 105-120 and low foaming performance, the polyvinyl chloride paste resin production step (S3) includes adding 1-3 parts of emulsion seeds, 2-4 parts of MSP seeds, 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate, 0.1-0.3 parts of copper sulfate, and 11,500-25,000 parts of vinyl chloride monomer into a reaction kettle, controlling the temperature to 49-56° C. and the pressure to 700-850 KPa to carry out a chain reaction, and after the reaction starts, adding 15,000-25,000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid caustic soda, 200-350 parts of sodium alkylbenzene sulfonate, 50-100 parts of potassium laurate, 5-10 parts of vitamin C acid, and 50-100 parts of a defoaming agent, and the reaction ends to obtain a polyvinyl chloride paste resin with a viscosity of 105-120 and low foaming performance.

4. The method for preparing a polyvinyl chloride paste resin according to claim 1, characterized in that: When producing a polyvinyl chloride paste resin with a high degree of polymerization of 150-165, the polyvinyl chloride paste resin production step (S3) includes adding 1-3 parts of emulsion seeds, 2-4 parts of MSP seeds, 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate, 0.1-1 parts of copper sulfate, 1-1.5 parts of potassium persulfate, 11,500-25,000 parts of vinyl chloride monomer, and 10-20 parts of dipropylene phthalate into a reaction kettle, and controlling The temperature is 49-56°C and the pressure is 700-850Kpa. A chain reaction is carried out. After the reaction starts, 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate, 40-100 parts of sodium lauryl polyoxyethylene ether sulfate, 3.5-10 parts of vitamin C acid and 50-100 parts of defoaming agent are added. When the reaction is completed, a polyvinyl chloride paste resin with a high degree of polymerization and a viscosity between 150-165 is obtained.

5. The method for preparing a polyvinyl chloride paste resin according to claim 1, characterized in that: When producing a polyvinyl chloride paste resin with a high degree of polymerization and a viscosity greater than 165, the polyvinyl chloride paste resin production step (S3) includes adding 1-3 parts of emulsion seeds, 2-4 parts of MSP seeds, 20,000-35,000 parts of hot desalted water, 5-20 parts of potassium dihydrogen phosphate, 0.1-1 parts of copper sulfate, 1-1.5 parts of potassium persulfate, 11,500-25,000 parts of vinyl chloride monomer, and 20-50 parts of dipropylene phthalate into a reaction kettle, and controlling The temperature is 49-56°C and the pressure is 700-850Kpa. A chain reaction is carried out. After the reaction starts, 15000-25000 parts of vinyl chloride monomer and 3-15 parts of 32% liquid alkali, 200-350 parts of sodium alkylbenzene sulfonate, 40-100 parts of sodium lauryl polyoxyethylene ether sulfate, 3.5-10 parts of vitamin C acid and 50-100 parts of defoaming agent are added. When the reaction is completed, a high-polymerization degree and high-strength polyvinyl chloride paste resin with a viscosity greater than 165 is obtained.

6. The method for preparing a polyvinyl chloride paste resin according to any one of claims 1 to 5, characterized in that: In the polyvinyl chloride paste resin production step (S3), when the temperature in the reactor reaches 4°C below the set temperature, vitamin C acid or potassium metabisulfite is added according to the intensity of the reaction.

7. The method for preparing a polyvinyl chloride paste resin according to claim 6, characterized in that: In the polyvinyl chloride paste resin production step (S3), vinyl chloride monomer is added 1 minute after the chain reaction starts, wherein, during the period when the cumulative amount of vinyl chloride monomer added is 0-(10000-20000) parts, it is added at a flow rate of 25000-45000 parts / h, and the remaining vinyl chloride monomer is added at a flow rate of 5000-5500 parts / h.

8. The method for preparing a polyvinyl chloride paste resin according to claim 7, characterized in that: In the polyvinyl chloride paste resin production step (S3), sodium alkylbenzene sulfonate or sodium dodecyl sulfate, and sodium lauryl polyoxyethylene ether sulfate or potassium laurate are added 5 minutes after the chain reaction starts.

9. The method for preparing a polyvinyl chloride paste resin according to claim 8, characterized in that: In the emulsion seed production step (S1), the reaction ends when the pressure in the reactor drops to 110-350Kpa; In the MSP seed production step (S2), the reaction ends when the pressure in the reactor drops to 110-350Kpa; In the polyvinyl chloride paste resin production step (S3), the reaction ends when the pressure in the reactor drops to 350-550 KPa.

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