Anti-sticking agent for vinyl chloride polymerization reaction as well as preparation method and application of anti-sticking agent

Abstract

The invention provides an anti-sticking agent for vinyl chloride polymerization reaction as well as a preparation method and application thereof, and relates to the technical field of anti-sticking agents. The anti-sticking agent comprises the following components in percentage by mass: 1-5% of naphthol, 2-5% of formaldehyde, 0.1-1% of trioxymethylene, 0.3-3% of sodium hydrosulfite, 1-4% of liquid caustic soda, 0.1-1% of benzenesulfonic acid, 1-2% of a dispersing agent and the balance of water. The preparation method comprises the following steps: (1) mixing formaldehyde and trioxymethylene, and adding sodium hydrosulfite; raising the temperature to obtain a chemical material mixture; (2) mixing water and caustic soda liquid, continuing to heat to 50-60 DEG C, and then mixing with the mixture of naphthol and the chemical material; finally, raising the temperature to 75-85 DEG C and carrying out heat preservation reaction to obtain a solution And (3) standing the solution, and mixing the supernate with benzenesulfonic acid and a dispersing agent to obtain the anti-sticking agent. The anti-sticking agent overcomes the problems of poor anti-sticking effect and poor wall coating effect of the existing anti-sticking agent, and prolongs the kettle cleaning period.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-sticking kettle agents, and in particular relates to an anti-sticking kettle agent for vinyl chloride polymerization reaction, a preparation method and an application thereof. Background Art

[0002] Polyvinyl chloride (PVC) is usually prepared by free radical addition polymerization, wherein the polymerization method is divided into suspension polymerization, emulsion polymerization and bulk polymerization. In industrial production, suspension polymerization is the main method, which includes the steps of adding pure water, liquefied vinyl chloride (VCM) monomer and dispersant into a reactor, then adding initiator and other additives, heating to a certain temperature, causing VCM monomer to undergo free radical polymerization to generate PVC particles, and continuously stirring to make the particle size of the particles uniform, and suspending the generated particles in water. However, in the implementation of this production method, there has always been a problem of sticking of the polymerization kettle. Sticking of the polymerization kettle will lead to a decrease in the heat transfer coefficient and production capacity of the polymerization kettle, a decrease in the monomer yield, and an increase in the cost of PVC products. At the same time, if the sticking material is mixed into the resin, "fish eyes" and black and yellow spots are very likely to appear during the resin processing and plasticization, thereby reducing the quality of the end product. In the suspension polymerization production of PVC, it is often necessary to clean the kettle, which is easy to destroy the production continuity, reduce the equipment operation rate, increase labor costs, and also cause harm to the personnel who clean the kettle due to vinyl chloride (VCM).

[0003] In recent years, the varieties of special PVC resins such as special resins, copolymer resins, and paste resins have continued to increase, and the output has increased year by year, which has also put forward higher requirements on the performance of anti-sticking agents. Therefore, it is necessary to pay attention to the problem of sticking in the polymerization kettle.

[0004] Chinese invention patent CN112266682A discloses a highly efficient anti-sticking agent for PVC suspension polymerization production and its preparation method. The anti-sticking agent comprises components: 1%-6% of o-hydroxybenzaldehyde, 1%-6% of 1,4,5,8-tetrahydroxynaphthalene, 1%-3% of 1-naphthol-4-carboxylic acid, 1%-4% of formaldehyde sodium sulfoxylate, 1%-3% of film-forming agent, 1%-2% of catalyst, 1%-2% of reducing protective agent, 5%-15% of methanol and the balance of deionized water. The preparation method is as follows: add 1,4,5,8-tetrahydroxynaphthalene and sodium hydroxide to a reaction kettle; drip o-hydroxybenzaldehyde, sodium formaldehyde sodium sulfoxylate and deionized water mixed solution and keep warm; drip 1-naphthol-4-carboxylic acid, sodium hydroxide and deionized water mixed solution and keep warm twice, add polyvinyl alcohol, reducing protective agent, methanol and the balance of deionized water, and stir to room temperature. The defect of this invention is that the aldehyde group is released too quickly during the reaction process, and the molecular weight of the condensation reaction with phenols cannot be controlled, so that a polymer product is easily formed. The product has no anti-sticking effect and increases the problem of fisheye residues in the PVC product.

[0005] Chinese invention patent CN111592808A discloses an anti-sticking agent for polyvinyl chloride suspension polymerization and its preparation method. The anti-sticking agent includes the following components by weight: 1 part of naphthol, 0.3-0.45 parts of sodium hydroxide, 0.15-0.45 parts of film-forming agent, 0.05-0.125 parts of penetrant, 1-3 parts of antifreeze and 50-100 parts of water. The invention improves the selectivity of the condensation reaction of naphthol and bleaching block by increasing pressure and raising temperature under nitrogen protection atmosphere and alkaline conditions, and the proportion of the monocondensation product of the target component of the anti-sticking agent prepared in the total condensate reaches more than 95%. However, the cleaning cycle of the anti-sticking agent is about 760-800 kettles, and the cleaning cycle is still short. And most of the anti-sticking agents in the prior art are strongly reducing substances, and the production process is oxygen-sensitive, which is easy to cause an increase in side reactions.

[0006] In view of this, it is necessary to provide an anti-sticking agent with good anti-sticking effect, long kettle cleaning cycle, high effective ingredient content and few impurities. It overcomes the shortcomings of the existing anti-sticking agent, which has relatively poor anti-sticking effect and poor wall coating effect, and is difficult to meet the needs of PVC polymerization production, and is conducive to industrial promotion and application. Summary of the invention

[0007] The present invention aims at the problems existing in the prior art, and provides an anti-sticking kettle agent for vinyl chloride polymerization reaction, a preparation method and an application thereof. Reducing powder with stronger reducing power than the anti-sticking kettle agent is added in advance to play a protective role; a formula containing trioxymethylene is adopted to control the slow release of aldehyde substances during the reaction process, thereby controlling the molecular weight of aldehyde and phenol polycondensation reactants, and making the polycondensation reaction stable. The present invention prepares the anti-sticking kettle agent by a specific method, overcomes the problems that the existing anti-sticking kettle agent has poor anti-sticking effect, poor wall coating effect, and cannot meet the production requirements of PVC polymerization, improves the kettle cleaning cycle, and significantly improves the anti-sticking effect of the obtained anti-sticking kettle agent.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] On the one hand, the present invention provides an anti-sticking agent for vinyl chloride polymerization reaction, which includes the following components by mass fraction: 1-5% naphthol, 2-5% formaldehyde, 0.1-1% trioxymethylene, 0.3-3% hydrosulfite, 1-4% liquid alkali, 0.1-1% benzenesulfonic acid, 1-2% dispersant and the balance water.

[0010] Preferably, the anti-sticking agent comprises the following components by mass fraction: 2-4% naphthol, 3.25-4% formaldehyde, 0.3-0.75% trioxymethylene, 0.5-3.5% hydrosulfite, 2-3% liquid alkali, 0.3-0.8% benzenesulfonic acid, 1.2-1.7% dispersant and the balance water.

[0011] Further preferably, the anti-sticking agent comprises the following components, calculated by mass fraction: 2.5% naphthol, 3.5% formaldehyde, 0.5% trioxymethylene, 2% hydrosulfite, 2.5% liquid alkali, 0.5% benzenesulfonic acid, 1.5% dispersant and the balance water.

[0012] Preferably, the liquid alkali is a 25-40wt% sodium hydroxide solution.

[0013] Further preferably, the liquid alkali is a 32 wt % sodium hydroxide solution.

[0014] Preferably, the hydrosulfite is sodium dithionite.

[0015] Preferably, the naphthol is selected from at least one of methyl naphthol, β-naphthol, substituted naphthols, bisphenol A and binaphthol.

[0016] Preferably, the dispersant is polyvinyl alcohol.

[0017] In the present invention, the water is not limited to industrial water, distilled water or desalted water, and different water has no significant effect on the technical effect.

[0018] On the other hand, the present invention provides a method for preparing the above-mentioned anti-sticking kettle agent, comprising the steps of:

[0019] (1) Chemical materials: After nitrogen replaces the air, add formaldehyde and trioxymethylene, raise the temperature to 25-35°C, and then add hydrosulfite; continue to raise the temperature to 45-55°C for reaction to obtain a chemical material mixture;

[0020] (2) Synthesis: water is heated to 35-45°C, liquid alkali is added, and the temperature is further raised to 50-60°C; then the mixture is mixed with naphthol and the chemical mixture of step (1); finally, the temperature is raised to 75-85°C and the reaction is kept for 2-3 hours to obtain a solution;

[0021] (3) The solution is allowed to stand, and the supernatant is mixed with benzenesulfonic acid and a dispersant to obtain an anti-sticking agent.

[0022] Preferably, step (1) is specifically as follows: after replacing the air with nitrogen, formaldehyde and trioxymethylene are added, and after heating to 30° C., hydrosulfite is added; and the temperature is further raised to 50° C. to obtain a chemical material mixture.

[0023] Preferably, in step (1), the reaction time is 2-4 hours.

[0024] Further preferably, in step (1), the reaction time is 3 h.

[0025] Preferably, in step (2), the water is heated to 40°C.

[0026] Preferably, in step (2), the temperature of the continued heating is 55° C., and then the mixture is mixed evenly with naphthol and the chemical mixture of step (1).

[0027] Preferably, in step (2), the final heating temperature is 80° C., and the reaction is kept warm for 2.5 hours.

[0028] Preferably, in step (3), the solution is left to stand for 7-10 days.

[0029] Preferably, step (3) is specifically as follows: the solution is allowed to stand, the supernatant is mixed with benzenesulfonic acid, and then with a dispersant, and stirred evenly to obtain an anti-sticking agent.

[0030] In the preparation method described in the present invention, nitrogen is passed throughout the process for protection.

[0031] Finally, the present invention provides application of the anti-sticking kettle agent in vinyl chloride polymerization reaction.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present invention makes specific use of the raw materials and the proportions of the anti-sticking agent, especially reacting the hydrosulfite with formaldehyde and trioxymethylene to produce bleaching powder. The reaction process can slowly release the aldehyde group, control the molecular weight of the aldehyde group and the classified polycondensation reactants, ensure smooth polycondensation and stable molecular weight, and the prepared anti-sticking agent has stable ingredients and less impurity ingredients.

[0034] 2. The present invention uses trioxymethylene as a reaction raw material and a raw material for improving reaction efficiency, which can increase the peak area of ​​effective substances and reduce impurity peaks, so that the anti-sticking agent can greatly improve the anti-sticking performance during the subsequent use of PVC polymerization production, and the kettle cleaning cycle can reach nearly 900 kettles or more.

[0035] 3. The present invention improves the components and their proportions, and the preparation method, controls the ratios between the raw materials, and the process parameters such as the temperature and time of each reaction stage, on the one hand, can effectively avoid the occurrence of side reactions; on the other hand, can effectively control the ratio of the two polycondensates generated in the product and the polymerization degree of the two polymers, and achieve the optimal ratio of the two polymers; the present invention controls the position and number of functional groups on the polymer, and ultimately makes the anti-sticking effect of the anti-sticking kettle agent significantly higher than that of existing products. The preparation process of the present invention is simple, the raw materials are easily available, the product use cost is low, and it is easy to promote and apply industrially.

[0036] 4. The present invention greatly improves the hydrophilicity and oleophobicity of the polymer through the specific selection of raw materials, and significantly reduces the wetting angle on the metal surface after spraying, thereby significantly improving the wall spraying effect.

[0037] 5. In the preparation of polyvinyl chloride, the amount of the anti-sticking agent of the present invention can be as low as about 100ppm, which is only one-third of the conventional amount. At the same time, the cleaning cycle of the anti-sticking agent of the present invention can be increased to nearly 900 kettles or more, and the cost of using a single kettle can be saved by about 40% compared with the traditional method. DETAILED DESCRIPTION

[0038] The following non-limiting examples can make those of ordinary skill in the art understand the present invention more comprehensively, but do not limit the present invention in any way. The following content is merely an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the present invention according to the disclosed content, and it should also belong to the scope of the present invention. When the embodiment gives a numerical range, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those of ordinary skill in the technical field to which the present invention belongs.

[0039] The present invention is further described below by way of specific examples. Unless otherwise specified, the various chemical reagents used in the examples of the present invention are obtained through conventional commercial channels.

[0040] In the following examples, the naphthol was purchased from Jiangsu Huada New Material Technology Co., Ltd.; the formaldehyde was purchased from Ningxia Xinao Chemical Co., Ltd.; the trioxymethylene was purchased from Suzhou Qihang Biotechnology Co., Ltd.; the β-naphthol was purchased from Nanjing Chemical Reagent Co., Ltd.; and the bisphenol A was purchased from Shanghai Huichao New Materials Co., Ltd. Products from different manufacturers have no significant effect on the effect.

[0041] Example 1

[0042] The invention discloses an anti-sticking agent for vinyl chloride polymerization reaction, the components of which are calculated by mass fraction: 2.5% naphthol, 3.5% formaldehyde, 0.5% trioxymethylene, 2% hydrosulfite, 2.5% liquid alkali (32wt% sodium hydroxide), 0.5% benzenesulfonic acid, 1.5% polyvinyl alcohol and the balance desalted water.

[0043] The preparation method of the anti-sticking kettle agent is:

[0044] (1) Chemical material: nitrogen is introduced into the container to replace the air to ensure nitrogen protection throughout the process; formaldehyde and trioxymethylene are added, and after the temperature is raised to 30°C, sodium hydrosulfite (sodium dithionite) is added; the temperature is continued to be raised to 50°C and the reaction is carried out for 3 hours to obtain a chemical material mixture;

[0045] (2) Synthesis: Ensure nitrogen protection throughout the process, heat the desalted water to 40° C., add a 32 wt% sodium hydroxide solution, and continue to heat it to 55° C.; then mix it evenly with the naphthol and the chemical mixture of step (1); finally heat it to 80° C. and keep it for 2.5 hours to obtain a solution;

[0046] (3) The solution was allowed to stand for 7 days to ensure nitrogen protection throughout the process. The supernatant was first mixed with benzenesulfonic acid and then with polyvinyl alcohol, and stirred evenly to obtain an anti-sticking agent.

[0047] Example 2

[0048] The invention discloses an anti-sticking agent for vinyl chloride polymerization reaction, the components of which are calculated by mass fraction as follows: 4% naphthol, 4% formaldehyde, 0.3% trioxymethylene, 3.5% hydrosulfite, 3% liquid alkali (32wt% sodium hydroxide), 0.8% benzenesulfonic acid, 1.7% polyvinyl alcohol and the balance desalted water.

[0049] The preparation method of the anti-sticking kettle agent is:

[0050] (1) Chemical material: nitrogen is introduced into the container to replace the air to ensure nitrogen protection throughout the process; formaldehyde and trioxymethylene are added, and after the temperature is raised to 30°C, sodium hydrosulfite (sodium dithionite) is added; the temperature is continued to be raised to 50°C and the reaction is carried out for 3 hours to obtain a chemical material mixture;

[0051] (2) Synthesis: Ensure nitrogen protection throughout the process, heat the desalted water to 40° C., add a 32 wt % sodium hydroxide solution, and continue to heat to 60° C.; then mix it evenly with the naphthol and the chemical mixture of step (1); finally heat it to 85° C. and keep it for 2 h to obtain a solution;

[0052] (3) The solution was allowed to stand for 7 days to ensure nitrogen protection throughout the process. The supernatant was first mixed with benzenesulfonic acid and then with polyvinyl alcohol, and stirred evenly to obtain an anti-sticking agent.

[0053] Example 3

[0054] The invention discloses an anti-sticking agent for vinyl chloride polymerization reaction, the components of which are calculated by mass fraction as follows: 2.5% naphthol, 3.25% formaldehyde, 0.75% trioxymethylene, 2% hydrosulfite, 2.5% liquid alkali (32wt% sodium hydroxide), 0.5% benzenesulfonic acid, 1.5% polyvinyl alcohol and the balance desalted water.

[0055] The preparation method of the anti-sticking kettle agent is:

[0056] (1) Chemical material: nitrogen is introduced into the container to replace the air to ensure nitrogen protection throughout the process; formaldehyde and trioxymethylene are added, and after the temperature is raised to 30°C, sodium hydrosulfite (sodium dithionite) is added; the temperature is continued to be raised to 50°C and the reaction is carried out for 3 hours to obtain a chemical material mixture;

[0057] (2) Synthesis: Ensure nitrogen protection throughout the process, heat the desalted water to 40° C., add a 32 wt% sodium hydroxide solution, and continue to heat it to 50° C.; then mix it evenly with the naphthol and the chemical mixture of step (1); finally heat it to 75° C. and keep it for 3 hours to obtain a solution;

[0058] (3) The solution was allowed to stand for 7 days to ensure nitrogen protection throughout the process. The supernatant was first mixed with benzenesulfonic acid and then with polyvinyl alcohol, and stirred evenly to obtain an anti-sticking agent.

[0059] Example 4

[0060] The difference from Example 1 is that the mass fractions of the anti-sticking agent components are different, specifically: 1% β-naphthol, 2% formaldehyde, 0.1% trioxymethylene, 0.3% hydrosulfite, 1% liquid alkali (32wt% sodium hydroxide), 0.1% benzenesulfonic acid, 1% polyvinyl alcohol and the remainder desalted water.

[0061] The rest are the same as in Example 1.

[0062] Example 5

[0063] The difference from Example 1 is that the mass fractions of the anti-sticking agent components are different, specifically: 5% bisphenol A, 5% formaldehyde, 1% trioxymethylene, 3% hydrosulfite, 4% liquid alkali (32wt% sodium hydroxide), 1% benzenesulfonic acid, 2% polyvinyl alcohol and the remainder desalted water.

[0064] The rest are the same as in Example 1.

[0065] Comparative Example 1

[0066] The difference from Example 1 is that the component hydrosulfite is not contained. The rest is the same as Example 1.

[0067] Comparative Example 2

[0068] The difference from Example 1 is that the mass fraction of the hydrosulfite is 5%. The rest is the same as Example 1.

[0069] Comparative Example 3

[0070] The difference from Example 1 is that the component trioxymethylene is not contained. The rest is the same as Example 1.

[0071] Comparative Example 4

[0072] The difference from Example 1 is that the mass fraction of trioxymethylene is 4%. The rest is the same as Example 1.

[0073] Comparative Example 5

[0074] The difference from Example 1 is that the preparation method of the anti-sticking agent is different, specifically, the final heating temperature in step (2) is different. The rest is the same as Example 1.

[0075] The preparation method of the anti-sticking kettle agent is:

[0076] Step (1) is the same as in Example 1;

[0077] Step (2) Synthesis: Ensure nitrogen protection throughout the process, heat the desalted water to 40° C., add a 32 wt% sodium hydroxide solution, and continue to heat to 55° C.; then mix evenly with naphthol and the chemical mixture of step (1); finally heat to 90° C. and keep warm for 2.5 hours to obtain a solution;

[0078] Step (3) is the same as in Example 1.

[0079] Comparative Example 6

[0080] The difference from Example 1 is that the preparation method of the anti-sticking agent is different, specifically, the time of the heat preservation reaction in step (2) is different. The rest is the same as Example 1.

[0081] The preparation method of the anti-sticking kettle agent is:

[0082] Step (1) is the same as in Example 1;

[0083] Step (2) Synthesis: Ensure nitrogen protection throughout the process, heat the desalted water to 40° C., add a 32 wt% sodium hydroxide solution, and continue to heat it to 55° C.; then mix it evenly with the naphthol and the chemical mixture of step (1); finally heat it to 80° C. and keep it for 3.5 hours to obtain a solution;

[0084] Step (3) is the same as in Example 1.

[0085] Comparative Example 7

[0086] The difference from Example 1 is that the preparation method of the anti-sticking agent is different, specifically the temperature of the continued heating in step (2) is different. The rest is the same as Example 1.

[0087] The preparation method of the anti-sticking kettle agent is:

[0088] Step (1) is the same as in Example 1;

[0089] Step (2) Synthesis: Ensure nitrogen protection throughout the process, heat the desalted water to 40° C., add a 32 wt% sodium hydroxide solution, and continue to heat to 40° C.; then mix evenly with naphthol and the chemical mixture of step (1); finally heat to 80° C. and keep warm for 2.5 hours to obtain a solution;

[0090] Step (3) is the same as in Example 1.

[0091] Experiment 1 Detection of the peak area of ​​the anti-sticking agent Detection method: high performance liquid chromatography. Mobile phase: 50% water, 50% ethanol; injection volume: 1 microliter; detection wavelength: 210nm.

[0092] Sample preparation: anti-sticking agent: ethanol = 1:1, filter with filter paper, then filter with filter membrane.

[0093] The effective peak areas and impurity peak areas of the anti-sticking agents prepared in the embodiments and comparative examples are shown in Table 1.

[0094] Among them, the effective peak area refers to the peak area of ​​the polycondensation reactant; the polycondensation reactant can improve the hydrophilicity and oleophobicity of the polymer, reduce the wetting angle on the metal surface after spraying, and effectively reduce the sticking phenomenon of PVC raw materials during the reaction process. The smaller the wetting angle, the weaker the interaction between molecules and the lower the surface tension of the droplets, making it easier for the liquid to wet the solid surface and less likely to stick to the kettle.

[0095] Impurity peak area refers to: the peak area of ​​reducing substances and excess raw material substances; spraying the above substances on the wall of the PVC kettle not only has no effect on reducing the number of kettle cleanings, but also causes an increase in the number of PVC fish eyes.

[0096] Test 2: Cleaning cycle detection

[0097] Number of cleanings of the PVC production kettle: When the material sticks to the kettle seriously again after the last cleaning of the PVC production kettle, causing the fisheye and other indicators to increase, it will be recorded as a new cleaning.

[0098] The anti-sticking kettle agents prepared in various embodiments and comparative examples are used in vinyl chloride polymerization reactions. The specific kettle cleaning cycles are shown in Table 1.

[0099] Table 1

[0100] Effective peak area, 10,000 Impurity peak area, 10,000 Cleaning cycle, kettle Example 1 4708 42 1034 Example 2 4058 62 905 Example 3 4387 48 963 Example 4 4556 109 889 Example 5 4599 66 911 Comparative Example 1 115 1248 76 Comparative Example 2 795 755 184 Comparative Example 3 1152 360 215 Comparative Example 4 2719 370 258 Comparative Example 5 2840 113 301 Comparative Example 6 1840 513 229 Comparative Example 7 3840 513 297

[0101] As can be seen from Table 1, in the preparation process of the embodiment, sodium hydrosulfite is added in advance, and sodium hydrosulfite reacts with formaldehyde to generate bleaching powder, thereby increasing the effective peak area of ​​the product. The addition of sodium hydrosulfite reduces the generation of side reactions and plays a protective role.

[0102] In the preparation process, the addition of trioxymethylene can react with formaldehyde to form formaldehyde-trioxymethylene components, slowly releasing aldehyde substances to make the polycondensation reaction stable, increase the target product content (molecular weight of the polycondensation compound) by 2-3 molecular weights, and increase the effective peak area; it can also serve as a catalyst component to accelerate the reaction rate.

[0103] In Comparative Example 1, the component hydrosulfite was not used, resulting in insufficient amount of bleaching powder produced, affecting the effective peak area, causing incomplete reaction of naphthol, increased impurity peak content, reduced kettle cleaning cycle, and increased side reactions.

[0104] In Comparative Example 2, the dosage of the hydrosulfur powder was changed to 5%. Excessive addition of hydrosulfur powder would cause adverse reactions and significantly reduce the effective peak area.

[0105] In Comparative Example 3, the component trioxymethylene was not used, and aldehydes and phenols underwent polycondensation to form polymer products, resulting in a decrease in effective ingredients.

[0106] In Comparative Example 4, the amount of trioxymethylene was changed to 4%, the purity of the synthesized bleaching agent was reduced, and in the subsequent preparation process of the anti-sticking agent, the effective ingredient was low and the impurity content was high.

[0107] In Comparative Example 5, the excessively high temperature caused the raw materials to decompose and fail to fully react, resulting in reduced product purity.

[0108] In Comparative Example 6, after the insulation time was extended, the amount of effective ingredients in the anti-sticking kettle agent was reduced and the reaction cost was increased.

[0109] In Comparative Example 7, since the chemical mixture of step (1) is unstable and sensitive to temperature, when the temperature is too high or too low, it will lead to material decomposition, increased side reactions, increased impurity peaks of the anti-sticking agent, and reduced effective peak area.

[0110] The present invention adds insurance powder in advance, and the reducing property of insurance powder is stronger than that of anti-sticking agent, which plays a protective role. By adding trioxymethylene to the process formula, the molecular weight of the aldehyde group and the phenol polycondensation reactant is controlled by slowly releasing the aldehyde group substance, so that the polycondensation reaction is stable. By changing the process, the anti-sticking effect of the anti-sticking agent is improved, and the problem that the anti-sticking effect and wall coating effect of the existing anti-sticking agent are poor and it is difficult to meet the insufficient demand for PVC polymerization production is overcome. The production process of the present invention is simple, the raw materials are easy to obtain, the product use cost is low, and it is convenient for industrial promotion and application.

[0111] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A desticking agent for vinyl chloride polymerization reaction, characterized in that: The composition includes the following components by mass fraction: 1-5% naphthol, 2-5% formaldehyde, 0.1-1% trioxymethylene, 0.3-3% hydrosulfite, 1-4% liquid alkali, 0.1-1% benzenesulfonic acid, 1-2% dispersant and the balance water.

2. The anti-sticking kettle agent according to claim 1, characterized in that Calculated by mass fraction, the composition includes: 2-4% naphthol, 3.25-4% formaldehyde, 0.3-0.75% trioxymethylene, 0.5-3.5% hydrosulfite, 2-3% liquid alkali, 0.3-0.8% benzenesulfonic acid, 1.2-1.7% dispersant and the balance water.

3. The anti-sticking kettle agent according to claim 2, characterized in that The composition includes, by mass fraction, 2.5% naphthol, 3.5% formaldehyde, 0.5% trioxymethylene, 2% hydrosulfite, 2.5% liquid alkali, 0.5% benzenesulfonic acid, 1.5% dispersant and the balance water.

4. The anti-sticking kettle agent according to any one of claims 1 to 3, characterized in that The liquid alkali is a 25-40wt% sodium hydroxide solution; the hydrosulfite is sodium dithionite; and the dispersant is polyvinyl alcohol.

5. The anti-sticking kettle agent according to claim 4, characterized in that The liquid alkali is a 32wt% sodium hydroxide solution.

6. The anti-sticking kettle agent according to any one of claims 1 to 3, characterized in that The naphthol is selected from at least one of methyl naphthol, β-naphthol, substituted naphthol, bisphenol A and binaphthol.

7. The method for preparing the anti-sticking agent according to any one of claims 1 to 6, characterized in that: Includes steps: (1) Chemical materials: After nitrogen replaces the air, add formaldehyde and trioxymethylene, raise the temperature to 25-35°C, and then add hydrosulfite; continue to raise the temperature to 45-55°C for reaction to obtain a chemical material mixture; (2) Synthesis: water is heated to 35-45°C, liquid alkali is added, and the temperature is further raised to 50-60°C; then the mixture is mixed with naphthol and the chemical mixture of step (1); finally, the temperature is raised to 75-85°C and the reaction is kept for 2-3 hours to obtain a solution; (3) The solution is allowed to stand, and the supernatant is mixed with benzenesulfonic acid and a dispersant to obtain an anti-sticking agent.

8. The preparation method according to claim 7, characterized in that: Step (1) is specifically as follows: after replacing the air with nitrogen, adding formaldehyde and trioxymethylene, heating to 30° C. and then adding hydrosulfite; continuing to heat to 50° C. to obtain a chemical material mixture; In step (1), the reaction time is 2-4 hours.

9. The preparation method according to claim 7, characterized in that: In step (2), the water is heated to 40°C; In step (2), the temperature of the continued heating is 55° C., and then the mixture is mixed evenly with naphthol and the chemical mixture of step (1); In step (2), the final heating temperature is 80° C., and the reaction is kept at this temperature for 2.5 hours; In step (3), the solution is left to stand for 7-10 days; Step (3) specifically comprises: allowing the solution to stand, taking the supernatant and mixing it with benzenesulfonic acid, then mixing it with a dispersant, and stirring evenly to obtain an anti-sticking kettle agent.

10. Use of the anti-sticking agent according to any one of claims 1 to 6 in vinyl chloride polymerization.