Anti-sticking agent for vinyl chloride polymerization and preparation method and application thereof

Abstract

This invention provides an anti-sticking reactor agent for vinyl chloride polymerization, its preparation method, and its application, relating to the field of anti-sticking reactor agent technology. The anti-sticking reactor agent of this invention comprises, by mass fraction: 1-5% naphthol, 2-5% formaldehyde, 0.1-1% paraformaldehyde, 0.3-3% sodium hydrosulfite, 1-4% liquid alkali, 0.1-1% benzenesulfonic acid, 1-2% dispersant, and the balance being water; its preparation method includes the following steps: (1) mixing formaldehyde and paraformaldehyde, adding sodium hydrosulfite; heating to obtain a chemical mixture; (2) mixing water and liquid alkali, continuing to heat to 50-60℃, then mixing with naphthol and the chemical mixture; finally heating to 75-85℃ and maintaining the temperature to obtain a solution; (3) allowing the solution to stand, taking the supernatant and mixing it with benzenesulfonic acid and dispersant to obtain the anti-sticking reactor agent. This invention overcomes the problems of poor anti-sticking effect and poor wall coating effect of existing anti-sticking reactor agents, and improves the reactor cleaning cycle.

Description

Technical Field

[0001] This invention belongs to the field of anti-sticking reactor technology, specifically relating to an anti-sticking reactor agent for vinyl chloride polymerization reaction, its preparation method, and its application. Background Technology

[0002] Polyvinyl chloride (PVC) is typically produced using free radical addition polymerization, which includes suspension polymerization, emulsion polymerization, and bulk polymerization. Industrial production primarily utilizes suspension polymerization, which involves adding pure water, liquefied vinyl chloride (VCM) monomer, and a dispersant to a reactor. Then, an initiator and other additives are added. After heating to a certain temperature, the VCM monomer undergoes a free radical polymerization reaction to produce PVC particles. Continuous stirring ensures uniform particle size and suspension of the particles in water. However, a persistent problem in this production process is reactor sticking. This sticking leads to a decrease in the reactor's heat transfer coefficient and production capacity, reduced monomer yield, and increased PVC product costs. Furthermore, if the sticking material mixes into the resin, it can easily cause "fish eyes" and black / yellow spots during resin processing and plasticizing, thus reducing the quality of the final product. Suspension polymerization of PVC frequently requires reactor cleaning, which can disrupt production continuity, reduce equipment operating rates, increase labor costs, and pose a hazard to personnel cleaning the reactor due to the presence of vinyl chloride (VCM).

[0003] In recent years, the variety of specialty PVC resins, such as special resins, copolymer resins, and paste resins, has been increasing, and their production volume has been rising year by year. This has placed higher demands on the performance of anti-sticking agents in polymerization reactors. Therefore, it is necessary to pay attention to the problem of adhesion to the polymerization reactor.

[0004] Chinese invention patent CN112266682A discloses a high-efficiency anti-sticking reactor agent for PVC suspension polymerization production and its preparation method. The anti-sticking reactor agent comprises the following components: 1%-6% o-hydroxybenzaldehyde, 1%-6% 1,4,5,8-tetrahydroxynaphthalene, 1%-3% 1-naphthol-4-carboxylic acid, 1%-4% sodium formaldehyde sulfoxylate, 1%-3% film-forming agent, 1%-2% catalyst, 1%-2% reducing agent, 5%-15% methanol, and the balance deionized water. The preparation method is as follows: 1,4,5,8-tetrahydroxynaphthalene and sodium hydroxide are added to a reactor; a mixture of o-hydroxybenzaldehyde, sodium formaldehyde sulfoxylate, and deionized water is added dropwise and kept at a constant temperature; a mixture of 1-naphthol-4-carboxylic acid, sodium hydroxide, and deionized water is added dropwise and kept at a constant temperature twice; polyvinyl alcohol, reducing agent, methanol, and the balance deionized water are added, and the mixture is stirred until room temperature is reached. The drawback of this invention is that the aldehyde group is released too quickly during the reaction, making it impossible to control the molecular weight of the condensation reaction with phenols, which easily leads to the formation of polymer products. These products do not have an anti-sticking effect and also increase the problem of fish-eye residue in PVC products.

[0005] Chinese invention patent CN111592808A discloses an anti-sticking reactor agent for suspension polymerization of polyvinyl chloride and its preparation method. The anti-sticking reactor agent comprises the following components in parts by weight: 1 part naphthol, 0.3-0.45 parts sodium hydroxide, 0.15-0.45 parts film-forming agent, 0.05-0.125 parts penetrant, 1-3 parts antifreeze, and 50-100 parts water. This invention improves the selectivity of the condensation reaction between naphthol and sodium formaldehyde sulfoxylate under a nitrogen protective atmosphere and alkaline conditions by pressurizing and heating. The resulting anti-sticking reactor agent achieves a target component mono-condensation product accounting for over 95% of the total condensate. However, the reactor cleaning cycle for this anti-sticking reactor agent is approximately 760-800 reactors, which is still relatively short. Furthermore, most existing anti-sticking reactor agents are strongly reducing substances, making the production process oxygen-sensitive and prone to increasing side reactions.

[0006] Therefore, there is a need for an anti-sticking agent that offers good anti-sticking performance, long cleaning cycle, high content of active ingredients, and low impurities. This would overcome the shortcomings of existing anti-sticking agents, which have relatively poor anti-sticking and coating effects, making it difficult to meet the needs of PVC polymerization production and facilitating their industrial application. Summary of the Invention

[0007] This invention addresses the problems of existing technologies by providing an anti-sticking reactor agent for vinyl chloride polymerization, its preparation method, and its application. A reducing powder with stronger reducing properties than the anti-sticking reactor agent is added beforehand to provide protection. A formulation containing trioxymethylene is used to control the slow release of aldehyde substances during the reaction, thereby controlling the molecular weight of the aldehyde and phenolic condensation reaction products and ensuring a stable condensation reaction. This invention, through a specific method for preparing the anti-sticking reactor agent, overcomes the problems of poor anti-sticking effect, poor wall coating effect, and inability to meet the needs of PVC polymerization production of existing anti-sticking reactor agents, improving the reactor cleaning cycle and significantly enhancing the anti-sticking effect of the obtained anti-sticking reactor agent.

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

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

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

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

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

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

[0014] Preferably, the sodium dithionite is sodium dithionite.

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

[0016] Preferably, the dispersant is polyvinyl alcohol.

[0017] In this invention, the water is not limited to industrial water, distilled water, or desalinated water, and different types of water have no significant impact on the technical effect.

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

[0019] (1) Chemical reaction: After replacing the air with nitrogen, formaldehyde and trioxymethylene are added, and the temperature is raised to 25-35℃ and sodium hydrosulfite is added; the temperature is further raised to 45-55℃ to carry out the reaction and obtain the chemical mixture.

[0020] (2) Synthesis: Heat water to 35-45℃, add liquid alkali, and continue to heat to 50-60℃; then mix it evenly with naphthol and the chemical mixture from step (1); finally heat to 75-85℃ and keep it at that temperature for 2-3 hours to obtain a solution;

[0021] (3) Let the solution stand, take the supernatant and mix it with benzenesulfonic acid and dispersant to obtain the anti-sticking agent.

[0022] Preferably, step (1) specifically involves: replacing the air with nitrogen, adding formaldehyde and trioxymethylene, heating to 30°C and then adding sodium hydrosulfite; continuing to heat to 50°C to obtain a chemical mixture.

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

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

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

[0026] Preferably, in step (2), the temperature for further heating is 55°C, and then the mixture is thoroughly mixed with naphthol and the chemical mixture from step (1).

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

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

[0029] Preferably, step (3) specifically involves: allowing the solution to stand, taking the supernatant and mixing it with benzenesulfonic acid, then mixing it with the dispersant, stirring evenly to obtain an anti-sticking agent.

[0030] The preparation method described in this invention is protected by nitrogen gas throughout the entire process.

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

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

[0033] 1. This invention makes specific use of the raw materials and their proportions for the anti-sticking agent, especially by reacting sodium hydrosulfite with formaldehyde and trioxymethylene to produce sodium formaldehyde sulfoxylate. The reaction process can slowly release aldehyde groups, control the molecular weight of aldehyde groups and different types of polycondensation reactants, and ensure stable polycondensation and molecular weight. The resulting anti-sticking agent has stable composition and low impurity content.

[0034] 2. This invention uses trioxymethylene as a reaction raw material and a raw material to improve reaction efficiency. It 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 in the subsequent PVC polymerization production process, and the cleaning cycle can reach nearly 900 cycles or more.

[0035] 3. This invention improves the components and their proportions, as well as the preparation method, controlling the ratio between raw materials and process parameters such as temperature and time at each reaction stage. This effectively avoids side reactions and allows for precise control of the proportions of the two condensation polymers in the product and the degree of polymerization of the two polymers, achieving an optimal ratio. By controlling the position and number of functional groups on the polymers, this invention ultimately achieves a significantly higher anti-sticking effect than existing products. The preparation process of this invention is simple, the raw materials are readily available, the product has low operating costs, and it is easy to promote and apply industrially.

[0036] 4. By specifically selecting raw materials, this invention greatly enhances the hydrophilicity and oleophobicity of polymers, significantly reduces the wetting angle on metal surfaces after spraying, and thus significantly improves the coating effect.

[0037] 5. In the preparation of polyvinyl chloride, the amount of the anti-sticking agent of this invention can be as low as about 100 ppm, which is only one-third of the conventional amount. At the same time, the cleaning cycle of the anti-sticking agent of this invention can be increased to nearly 900 batches or more, and the cost per batch can be reduced by about 40% compared with the traditional method. Detailed Implementation

[0038] The following non-limiting embodiments are intended to provide a more comprehensive understanding of the invention by those skilled in the art, but do not limit the invention in any way. The following description is merely an exemplary illustration of the scope of protection claimed by the invention. Those skilled in the art can make various changes and modifications to the invention based on the disclosed content, and these should also fall within the scope of protection claimed by the invention. When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the invention, the two endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by those skilled in the art to which this invention pertains.

[0039] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention are obtained through conventional commercial means.

[0040] In the following examples, the naphthol was purchased from Jiangsu Huada New Material Technology Co., Ltd.; the formaldehyde was purchased from Ningxia Xin'ao 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 Material Co., Ltd. Products from different manufacturers did not significantly affect the efficacy.

[0041] Example 1

[0042] An anti-sticking reactor agent for vinyl chloride polymerization reaction, comprising the following components by mass fraction: 2.5% naphthol, 3.5% formaldehyde, 0.5% trioxymethylene, 2% sodium hydrosulfite, 2.5% liquid alkali (32wt% sodium hydroxide), 0.5% benzenesulfonic acid, 1.5% polyvinyl alcohol, and the balance being demineralized water.

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

[0044] (1) Chemical reaction: Nitrogen gas is introduced into the container to replace the air and ensure nitrogen protection throughout the process; formaldehyde and trioxymethylene are added, and after the temperature is raised to 30°C, sodium dithionite is added; the temperature is further raised to 50°C and the reaction is kept at the temperature for 3 hours to obtain the chemical mixture;

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

[0046] (3) Let the solution stand for 7 days to ensure nitrogen protection throughout the process. Take the supernatant and mix it with benzenesulfonic acid, then mix it with polyvinyl alcohol and stir evenly to obtain the anti-sticking agent.

[0047] Example 2

[0048] An anti-sticking reactor agent for vinyl chloride polymerization reaction, comprising the following components by mass fraction: 4% naphthol, 4% formaldehyde, 0.3% trioxymethylene, 3.5% sodium hydrosulfite, 3% liquid alkali (32wt% sodium hydroxide), 0.8% benzenesulfonic acid, 1.7% polyvinyl alcohol, and the balance being demineralized water.

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

[0050] (1) Chemical reaction: Nitrogen gas is introduced into the container to replace the air and ensure nitrogen protection throughout the process; formaldehyde and trioxymethylene are added, and after the temperature is raised to 30°C, sodium dithionite is added; the temperature is further raised to 50°C and the reaction is kept at the temperature for 3 hours to obtain the chemical mixture;

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

[0052] (3) Let the solution stand for 7 days to ensure nitrogen protection throughout the process. Take the supernatant and mix it with benzenesulfonic acid, then mix it with polyvinyl alcohol and stir evenly to obtain the anti-sticking agent.

[0053] Example 3

[0054] An anti-sticking reactor agent for vinyl chloride polymerization reaction, comprising the following components by mass fraction: 2.5% naphthol, 3.25% formaldehyde, 0.75% trioxymethylene, 2% sodium hydrosulfite, 2.5% liquid alkali (32wt% sodium hydroxide), 0.5% benzenesulfonic acid, 1.5% polyvinyl alcohol, and the balance being demineralized water.

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

[0056] (1) Chemical reaction: Nitrogen gas is introduced into the container to replace the air and ensure nitrogen protection throughout the process; formaldehyde and trioxymethylene are added, and after the temperature is raised to 30°C, sodium dithionite is added; the temperature is further raised to 50°C and the reaction is kept at the temperature for 3 hours to obtain the chemical mixture;

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

[0058] (3) Let the solution stand for 7 days to ensure nitrogen protection throughout the process. Take the supernatant and mix it with benzenesulfonic acid, then mix it with polyvinyl alcohol and stir evenly to obtain the anti-sticking agent.

[0059] Example 4

[0060] Unlike Example 1, the mass fraction of the anti-sticking agent components is different, specifically: 1% β-naphthol, 2% formaldehyde, 0.1% paraformaldehyde, 0.3% sodium hydrosulfite, 1% liquid alkali (32wt% sodium hydroxide), 0.1% benzenesulfonic acid, 1% polyvinyl alcohol and the balance demineralized water.

[0061] Everything else is the same as in Example 1.

[0062] Example 5

[0063] Unlike Example 1, the mass fraction of the anti-sticking agent components is different, specifically: 5% bisphenol A, 5% formaldehyde, 1% paraformaldehyde, 3% sodium hydrosulfite, 4% liquid alkali (32wt% sodium hydroxide), 1% benzenesulfonic acid, 2% polyvinyl alcohol, and the balance demineralized water.

[0064] Everything else is the same as in Example 1.

[0065] Comparative Example 1

[0066] Unlike Example 1, this example does not contain sodium hydrosulfite. Everything else is the same as in Example 1.

[0067] Comparative Example 2

[0068] Unlike Example 1, the mass fraction of sodium hydrosulfite is 5%. Everything else is the same as in Example 1.

[0069] Comparative Example 3

[0070] Unlike Example 1, this example does not contain the component trioxymethylene. Everything else is the same as in Example 1.

[0071] Comparative Example 4

[0072] Unlike Example 1, the mass fraction of paraformaldehyde is 4%. Everything else is the same as in 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. Everything else is the same as in Example 1.

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

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

[0077] Step (2) Synthesis: Ensure nitrogen protection throughout the process, heat the deionized water to 40°C, add a 32wt% sodium hydroxide solution, and continue heating to 55°C; then mix it evenly with naphthol and the chemical mixture from step (1); finally heat it to 90°C and keep it at that temperature for 2.5 hours to obtain the 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. Everything else is the same as in Example 1.

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

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

[0083] Step (2) Synthesis: Ensure nitrogen protection throughout the process, heat the deionized water to 40°C, add a 32wt% sodium hydroxide solution, and continue heating to 55°C; then mix it evenly with naphthol and the chemical mixture from step (1); finally heat it to 80°C and keep it at that temperature for 3.5 hours to obtain the 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 at which the temperature is further increased in step (2). Everything else is the same as in Example 1.

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

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

[0089] Step (2) Synthesis: Ensure nitrogen protection throughout the process, heat the deionized water to 40°C, add a 32wt% sodium hydroxide solution, and continue heating to 40°C; then mix it evenly with naphthol and the chemical mixture from step (1); finally heat it to 80°C and keep it at that temperature for 2.5 hours to obtain the 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 μL; Detection wavelength: 210 nm.

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

[0093] The effective peak area and impurity peak area of ​​the anti-sticking agents prepared in each embodiment and comparative example are shown in Table 1.

[0094] The effective peak area refers to the peak area of ​​the condensation reactants. Condensation reactants can enhance the hydrophilicity and oleophobicity of the polymer, reduce the wetting angle on the metal surface after spraying, and effectively reduce the sticking of PVC raw materials to the reactor during the reaction process. A smaller wetting angle weakens the intermolecular interactions, reduces the surface tension of the droplets, and makes it easier for the liquid to wet the solid surface, thus reducing the likelihood of sticking to the reactor.

[0095] Impurity peak area refers to the peak area of ​​reducing substances and excess raw material substances. Spraying these substances onto the PVC reactor wall not only fails to reduce the number of cleaning cycles, but also increases the number of PVC fish eyes.

[0096] Experiment 2 Cleaning Cycle Detection

[0097] PVC production reactor cleaning frequency: When the PVC production reactor is cleaned and the material sticks to the reactor again, causing the fish-eye and other indicators to rise, it is counted as a new cleaning.

[0098] The specific cleaning cycle for the anti-sticking agents prepared in each embodiment and comparative example in the application of vinyl chloride polymerization reaction is shown in Table 1.

[0099] Table 1

[0100] 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 shown in Table 1, in the examples, sodium hydrosulfite was added in advance during the preparation process. The sodium hydrosulfite reacts with formaldehyde to form sodium formaldehyde sulfoxylate, thereby increasing the effective peak area of ​​the product. The addition of sodium hydrosulfite reduces the formation of side reactions and plays a protective role.

[0102] In the preparation process of the example, trioxymethylene is added, which can react with formaldehyde to formaldehyde-trioxymethylene components, and the aldehyde group is slowly released, so that the condensation reaction is stable, the content of the target product (molecular weight of the condensation compound) is increased by 2-3 molecular weights, and the effective peak area is increased; it can also be used as a catalyst to accelerate the reaction rate.

[0103] In Comparative Example 1, the absence of sodium hydrosulfite resulted in insufficient formation of sodium formaldehyde sulfoxylate, affecting the effective peak area, leading to incomplete reaction of naphthol, increased impurity peak content, reduced cleaning cycle, and increased side reactions.

[0104] In Comparative Example 2, the amount of sodium hydrosulfite was changed to 5%. Adding too much sodium hydrosulfite would cause adverse effects and significantly reduce the effective peak area.

[0105] In Comparative Example 3, without the use of component trioxymethylene, aldehydes and phenols underwent a condensation reaction to form polymers, resulting in a reduction in the effective components.

[0106] In Comparative Example 4, changing the amount of trioxymethylene to 4% resulted in a decrease in the purity of the synthesized sodium formaldehyde sulfoxylate, leading to low effective components and high impurity content during the subsequent preparation of the anti-sticking agent.

[0107] In Comparative Example 5, excessively high temperatures caused the raw materials to decompose, preventing them from reacting fully and resulting in a decrease in product purity.

[0108] In Comparative Example 6, extending the heat preservation time reduced the amount of effective components in the anti-sticking agent and increased the reaction cost.

[0109] In Comparative Example 7, because the chemical mixture in step (1) is unstable and sensitive to temperature, excessively high or low temperatures can lead to material decomposition, increased side reactions, increased impurity peaks in the anti-sticking agent, and reduced effective peak area.

[0110] This invention incorporates sodium hydrosulfite in advance; sodium hydrosulfite has stronger reducing properties than the anti-sticking agent, thus providing protection. By adding trioxymethylene to the process formulation, the molecular weight of the aldehyde group reacting with the phenolic polycondensation product is controlled through the slow release of the aldehyde group, ensuring a stable polycondensation reaction. By modifying the process, the anti-sticking effect of the anti-sticking agent is improved, overcoming the problems of poor anti-sticking and coating effects of existing anti-sticking agents, which are insufficient to meet the needs of PVC polymerization production. This invention features a simple production process, readily available raw materials, low product cost, and is easy to promote and apply industrially.

[0111] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. An anti-sticking reactor agent for vinyl chloride polymerization, characterized in that, The composition, by mass fraction, includes: 1-5% naphthol, 2-5% formaldehyde, 0.1-1% paraformaldehyde, 0.3-3% sodium hydrosulfite, 1-4% liquid alkali, 0.1-1% benzenesulfonic acid, 1-2% dispersant, and the balance being water.

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

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

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

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

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

7. The method for preparing the anti-sticking agent according to any one of claims 1-6, characterized in that, Including the following steps: (1) Chemical reaction: After replacing the air with nitrogen, formaldehyde and trioxymethylene are added, and the temperature is raised to 25-35℃ and then sodium hydrosulfite is added; the temperature is further raised to 45-55℃ to carry out the reaction and obtain the chemical mixture. (2) Synthesis: Heat water to 35-45℃, add liquid alkali, and continue to heat to 50-60℃; then mix it evenly with naphthol and the chemical mixture from step (1); finally heat to 75-85℃ and keep it at that temperature for 2-3 hours to obtain a solution; (3) Let the solution stand, take the supernatant and mix it with benzenesulfonic acid and dispersant to obtain the anti-sticking agent.

8. The preparation method according to claim 7, characterized in that, Step (1) is as follows: After replacing the air with nitrogen, formaldehyde and trioxymethylene are added, and the temperature is raised to 30°C and then sodium hydrosulfite is added; the temperature is further raised to 50°C to obtain a chemical 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 a temperature of 40°C; In step (2), the temperature for further heating is 55°C, and then the mixture is thoroughly mixed with naphthol and the chemical mixture from step (1). In step (2), the final temperature is 80°C, and the reaction is maintained at that temperature for 2.5 hours. In step (3), the solution is left to stand for 7-10 days; Step (3) is as follows: let the solution stand, take the supernatant and mix it with benzenesulfonic acid, then mix it with the dispersant and stir evenly to obtain the anti-sticking agent.

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