CN110885387A

CN110885387A - Composite assistant for polyvinyl chloride polymerization

Info

Publication number: CN110885387A
Application number: CN201911283823.9A
Authority: CN
Inventors: 赵长森; 张凤凤; 张强; 王鑫龙; 牛强
Original assignee: Erdos Han Bo Technology Co Ltd
Current assignee: Erdos Han Bo Technology Co Ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2020-03-17
Anticipated expiration: 2039-12-13
Also published as: CN110885387B

Abstract

The invention relates to the technical field of polyvinyl chloride production, in particular to a composite auxiliary agent for polyvinyl chloride polymerization, which comprises the following components in percentage by weight: 5-40% of polyether defoaming agent, 5-30% of antioxidant, 5-15% of heat stabilizer and 40-80% of antistatic agent.

Description

Composite assistant for polyvinyl chloride polymerization

Technical Field

The invention relates to the technical field of polyvinyl chloride production, in particular to a composite auxiliary agent for polyvinyl chloride polymerization.

Background

Polyvinyl chloride (pvc), which is an initiator for Vinyl Chloride Monomer (VCM), in the presence of peroxides, azo compounds, etc.; or a polymer polymerized by a free radical polymerization mechanism under the action of light and heat. Polyvinyl chloride is one of five synthetic resins in the world, is once the most productive general plastic in the world, and is widely applied. The product has wide application in building materials, industrial products, daily necessities, floor leathers, floor tiles, artificial leathers, pipes, wires and cables, packaging films, bottles, foaming materials, sealing materials, fibers and the like. Polyvinyl chloride has the advantages of excellent performance, strong universality and low price.

At present, there are three methods for producing polyvinyl chloride: namely a calcium carbide acetylene method, an ethylene oxychlorination method and an alkyne polymerization method. The acetylene method of calcium carbide uses calcium carbide to produce acetylene gas, and the raw materials for ethylene oxychlorination and alkyne polymerization are produced by petroleum cracking.

Depending on the polymerization process, polyvinyl chlorides can be divided into four main groups: suspension process polyvinyl chloride, emulsion process polyvinyl chloride, bulk process polyvinyl chloride, and solution process polyvinyl chloride. The suspension method of polyvinyl chloride is a variety with the largest yield, and accounts for about 80% of the total yield of the PVC. Adding pure water, liquefied VCM monomer and dispersing agent into a reaction kettle, then adding initiator and other auxiliary agents, heating to a certain temperature, and carrying out free radical polymerization reaction on the VCM monomer to generate PVC particles. Continuous stirring makes the particle size of the particles uniform and the resulting particles are suspended in water.

At present, domestic polyvinyl chloride is mainly prepared by calcium carbide suspension polymerization. The whole production process comprises three working sections of polymerization, steam stripping and drying, vinyl chloride monomer is used as a raw material, deionized water is used as an aqueous medium, and a dispersing agent, an initiator, a terminator, an anti-sticking kettle agent, a buffering agent, a defoaming agent, liquid caustic soda and a gas phase polymerization inhibitor are used as main additives.

PVC is white powder with an amorphous structure, the branching degree is small, the relative density is about 1.4, the glass transition temperature is 77-90 ℃, decomposition starts at about 170 ℃, the stability to light and heat is poor, the PVC can be decomposed to generate hydrogen chloride at more than 100 ℃ or after long-time sunshine insolation, further the hydrogen chloride is automatically catalyzed and decomposed to cause color change, the physical and mechanical properties are also rapidly reduced, and a stabilizer must be added in practical application to improve the stability to heat and light.

With the current situation that the supply of domestic polyvinyl chloride resin is larger than the demand, the requirements of downstream processing enterprises on the polyvinyl chloride resin are stricter, and the thermal stability and the flow property of the resin are important indexes for the investigation. In addition, compared with the imported polyvinyl chloride resin, the thermal stability and the flow property of the domestic resin are different, and the price of the resin is not as good as that of the imported product. In order to improve the indexes of the polyvinyl chloride resin, some domestic manufacturers adopt technical improvement measures such as monomer recovery rectification, monomer solid alkali drying and the like, the measures have the defects of large investment and high operation cost, and the effect is mostly unexpected.

Chinese patent CN101914250A discloses a preparation method of an environment-friendly high-fluidity high-thermal-stability modified polyvinyl chloride master batch. It comprises the following steps: 1) adding 100 parts by weight of polyvinyl chloride and 100-2000 parts by weight of lanthanum-tin composite stabilizer into a high-speed mixer, mixing to 50-80 ℃, discharging, adding into a cold mixer, mixing and cooling, cooling to 40 ℃, adding 100-2000 parts by weight of acrylate processing aid, 100-2000 parts by weight of internal lubricant, 50-500 parts by weight of external lubricant and 100-5000 parts by weight of nano rigid particles, and fully mixing to obtain a polyvinyl chloride composite; 2) adding the polyvinyl chloride compound into a reaction kettle, heating to melt the polyvinyl chloride compound, stirring to uniformly mix the polyvinyl chloride compound, cooling, granulating and drying. The modified polyvinyl chloride finally obtained by the method has good processing fluidity, thermal stability and mechanical property, but the properties of all aspects cannot meet the requirements of part of enterprises and need to be further improved.

Chinese patent application CN110078845A discloses a high-efficiency water-soluble terminator for a polyvinyl chloride polymerization system, a preparation method and application thereof, belonging to the technical field of polyvinyl chloride. The patent application discloses a high-efficiency environment-friendly water-soluble terminator for a polyvinyl chloride polymerization system, which comprises an aqueous terminator, a heat stabilizer, a free radical type aqueous polymerization inhibitor, a solubilizer, a pH regulator and deionized water, and the specific preparation method comprises the following steps: firstly adding deionized water, then sequentially adding a pH regulator, a water-based terminator, a free radical type water-based polymerization inhibitor, a heat stabilizer and a solubilizer, mixing, stirring uniformly and discharging. The water-soluble terminator applied by the patent can effectively improve the aging whiteness and the heat stability time of a polyvinyl chloride product in the process of terminating reaction, and can also rapidly, safely and efficiently terminate the reaction. The application of the patent improves the whiteness and the thermal stability time of the polyvinyl chloride to a certain extent, but has little influence on the flow property of the polyvinyl chloride, and the thermal stability of the polyvinyl chloride needs to be further improved.

Therefore, it is necessary to develop a compounding aid for polyvinyl chloride polymerization that can solve the above-mentioned problems.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides the composite auxiliary agent for polyvinyl chloride polymerization, which can obviously improve the thermal stability, aging whiteness and fluidity of polyvinyl chloride, and has the advantages of low investment, low operation cost and quick response.

The invention is realized by the following technical scheme:

a composite auxiliary agent for polyvinyl chloride polymerization comprises the following components in percentage by weight: 5-40% of polyether defoaming agent, 5-30% of antioxidant, 5-15% of heat stabilizer and 40-80% of antistatic agent.

Preferably, the polyether defoamer comprises one or more of polyoxypropylene ethylene oxide glycerol ether, polyoxyethylene polyoxypropylene pentaerythritol ether and phenethyl phenol polyoxyethylene ether.

The polyether defoamer rapidly eliminates foam generated in the polymerization process, stabilizes a stripping section and ensures that Vc residue is qualified.

More preferably, the polyether defoamer comprises one or two of polyoxyethylene polyoxypropylene pentaerythritol ether and phenethyl phenol polyoxyethylene ether.

Preferably, the antioxidant comprises one or more of antioxidant 264, antioxidant 1024, antioxidant 1098, antioxidant 1076 and antioxidant 1010.

More preferably, the antioxidant comprises one or more of antioxidant 264, antioxidant 1098 and antioxidant 1010.

Preferably, the heat stabilizer comprises one or more of calcium acetylacetonate, monopentaerythritol, dipentaerythritol, epoxidized soybean oil and epoxidized castor oil.

More preferably, the heat stabilizer comprises one or more of calcium acetylacetonate, monopentaerythritol and epoxidized soybean oil.

More preferably, the heat stabilizer is a mixture of pentaerythritol and epoxidized soybean oil.

More preferably, the mass ratio of the pentaerythritol to the epoxidized soybean oil is 1:1 to 1: 2.

The antioxidant and the heat stabilizer are adsorbed by the polyvinyl chloride resin particles to continuously eliminate free radicals, oxidation groups and unstable structures of the resin, so that the heat stability of the resin is improved.

Preferably, the antistatic agent comprises one or more of methanol, ethanol, isopropanol, ethylene glycol and glycerol.

More preferably, the antistatic agent comprises one or more of methanol, isopropanol and ethanol.

The antistatic agent remains on the surface of the resin, reduces static electricity generated by friction between resins in the gas conveying and packaging processes, and improves the flowing property and the apparent density.

The composite additive is prepared by sequentially mixing a polyether defoamer, an antioxidant, a heat stabilizer and an antistatic agent according to a formula.

The invention also relates to the application of the composite auxiliary agent in preparing polyvinyl chloride by polymerizing vinyl chloride monomers.

Preferably, the compounding aid is added after the vinyl chloride monomer completes the polymerization reaction.

Preferably, the polymerization is a suspension polymerization.

Specifically, vinyl chloride monomer completes suspension polymerization reaction in a polymerization kettle and enters a slurry tank, and the composite additive is injected into the slurry tank through a defoaming agent storage tank and is uniformly stirred.

Preferably, the composite auxiliary agent accounts for 0.026% -0.077% of the mass of the vinyl chloride monomer.

The invention has the beneficial effects that:

the polyether defoamer in the composite additive disclosed by the invention can be used for rapidly eliminating foam generated in the polymerization process, stabilizing the stripping section and ensuring that Vc residue is qualified; the antioxidant and the heat stabilizer are adsorbed by the polyvinyl chloride resin particles to continuously eliminate free radicals, oxidation groups and unstable structures of the resin, so that the heat stability of the resin is improved, the heat aging whiteness is improved by more than 2 points, and the heat stabilization time is improved by more than 2 min; the antistatic agent remains on the surface of the resin, reduces static electricity generated by friction between the resins in the gas conveying and packaging processes, improves the flowing property and the apparent density, reduces the flowing time of the resin by more than 2s, and improves the apparent density by more than 0.01 g/mL.

The invention has simple operation, low investment and operation cost, and remarkable effect of improving the thermal stability and the fluidity.

Detailed Description

The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

The composite assistants of examples 1 to 8 according to the invention and comparative examples 1 to 6 were added to the PVC polymerization as follows:

the specific method for PVC suspension polymerization comprises the following steps:

1) at 105m³Steam is introduced into the polymerization kettle and a kettle top condenser, circulating water is introduced into a jacket, 12kg of Italian yellow anti-sticking agent (produced by Vast Bokejiu Co., Ltd. of Ordos) is added, the anti-sticking agent is atomized and adhered to the inner wall of the polymerization kettle and the lower part of the kettle top condenser, and a high-pressure water pump is started to flush until the discharged water is clean.

2) At 105m³Adding 0.7kg of sodium bicarbonate in a polymerization kettle in a dry basis amount for buffering the change of the pH value in the polymerization process; adding deionized water into a polymerization kettle, and adding the deionized water when the adding amount reaches 3m³And then, vinyl chloride monomer addition and water injection are synchronously carried out, 41t of deionized water is injected, and 39 tons of monomer are added.

3) After the monomer and the deionized water are mixed for 180s, 7kg of polyvinyl alcohol dispersant dry base with alcoholysis degree of 72%, 28kg of polyvinyl alcohol dispersant dry base with alcoholysis degree of 80% and 8kg of polyvinyl alcohol dispersant with alcoholysis degree of 50% and mass concentration of 40% are respectively injected, the mixing is delayed for 180s, 20kg of initiator dry base (15 kg of EHP dry base and 5kg of CNP dry base) is added, the reaction temperature in the kettle is controlled to be 56.5 ℃ in the whole process, the reaction water injection rate is 4.6t/h, when the pressure in the kettle is reduced by 0.08Mpa, 18.5kg of HB-101 terminator (produced by Hanboke technology Limited company in Orients city) is added into the kettle to terminate the reaction, and SG-5 type polyvinyl chloride resin slurry is obtained.

4) And pumping the resin slurry into a slurry tank, adding the composite additive from a defoaming agent storage tank, stirring for 0.5h, carrying out steam stripping, drying, sampling detection, and packaging and forming to obtain the resin slurry.

Example 1

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 15kg of composite auxiliary agent from a defoaming agent storage tank, wherein the composite auxiliary agent comprises the following components in percentage by mass: 15% of polyoxypropylene ethylene oxide glycerol ether, 26415% of antioxidant, 5% of monopentaerythritol, 5% of epoxidized soybean oil and 60% of ethanol. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Example 2

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 15kg of composite auxiliary agent from a defoaming agent storage tank, wherein the composite auxiliary agent comprises the following components in percentage by mass: 15% of polyoxyethylene polyoxypropylene pentaerythritol ether, 102415% of antioxidant, 5% of dipentaerythritol, 5% of epoxy castor oil and 60% of methanol. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Example 3

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 15kg of composite auxiliary agent from a defoaming agent storage tank, wherein the composite auxiliary agent comprises the following components in percentage by mass: 10% of polyoxypropylene ethylene oxide glycerol ether, 26410% of antioxidant, 2.5% of monopentaerythritol, 5% of epoxidized soybean oil and 72.5% of ethanol. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Example 4

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 15kg of composite auxiliary agent from a defoaming agent storage tank, wherein the composite auxiliary agent comprises the following components in percentage by mass: 20% of polyoxypropylene ethylene oxide glycerol ether, 26420% of antioxidant, 5% of monopentaerythritol, 10% of epoxidized soybean oil and 45% of ethanol. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Example 5

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 10kg of composite auxiliary agent from a defoaming agent storage tank, wherein the composite auxiliary agent comprises the following components in percentage by mass: 15% of polyoxypropylene ethylene oxide glycerol ether, 26415% of antioxidant, 5% of monopentaerythritol, 5% of epoxidized soybean oil and 60% of ethanol. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Example 6

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 20kg of composite auxiliary agent from a defoaming agent storage tank, wherein the composite auxiliary agent comprises the following components in percentage by mass: 15% of polyoxypropylene ethylene oxide glycerol ether, 26415% of antioxidant, 5% of monopentaerythritol, 5% of epoxidized soybean oil and 60% of ethanol. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Example 7

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 30kg of composite auxiliary agent from a defoaming agent storage tank, wherein the composite auxiliary agent comprises the following components in percentage by mass: 15% of polyoxypropylene ethylene oxide glycerol ether, 26415% of antioxidant, 5% of monopentaerythritol, 5% of epoxidized soybean oil and 60% of ethanol. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Example 8

The difference from the embodiment 7 is only that the composite auxiliary agent comprises the following components in percentage by mass: 15% of polyoxypropylene ethylene oxide glycerol ether, 26415% of antioxidant, 10% of epoxidized soybean oil and 60% of ethanol, and the rest conditions are unchanged. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Comparative example 1

The difference from the example 1 is that no polyoxypropylene ethylene oxide glycerol ether is added into the composite auxiliary agent, and the other components are not used. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Comparative example 2

The difference from the example 1 is that the antioxidant 264, the monopentaerythritol, the epoxidized soybean oil and the ethanol are not added in the composite auxiliary agent, and the dosage of the polyoxypropylene ethylene oxide glycerol ether is not changed. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Comparative example 3

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 15kg of composite auxiliary agent from a defoaming agent storage tank, wherein the composite auxiliary agent comprises the following components in percentage by mass: 15% of polyoxypropylene ethylene oxide glycerol ether and 85% of ethanol, and the antioxidant 264, the heat stabilizer monopentaerythritol and the epoxidized soybean oil are not contained. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Comparative example 4

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 15kg of defoaming thermostable composite assistant from a defoaming agent storage tank, wherein the defoaming agent comprises the following components in percentage by mass: 15% of polyoxypropylene ethylene oxide glycerol ether, 5% of monopentaerythritol, 5% of epoxidized soybean oil and 75% of ethanol, and does not contain antioxidant 264. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Comparative example 5

Pumping polyvinyl chloride resin slurry into a slurry tank, and adding 15kg of defoaming thermostable composite assistant from a defoaming agent storage tank, wherein the defoaming agent comprises the following components in percentage by mass: 15% of polyoxypropylene ethylene oxide glycerol ether, 26415% of antioxidant and 70% of ethanol, and monopentaerythritol and epoxidized soybean oil which do not contain heat stabilizers. Stripper foam profile, heat aged whiteness, heat stabilization time, flow time, and apparent density, as in table 1.

Comparative example 6

The difference from the example 1 is only that the polyoxypropylene ethylene oxide glycerol ether in the compounding aid is replaced by an equal amount of fatty acid ether, and the other conditions are the same.

Test example 1

The stripper operating conditions of examples 1-8 and comparative examples 1-6 and the thermally aged whiteness (160 ℃, 10min), thermal stabilization time (oven method), flow time, and apparent density index results for the PVC resin are shown in table 1. The specific test method for the whiteness, the thermal stability time and the apparent density of the thermal aging is referred to the national standard GB/T5761-. The specific test method of the flow time refers to the method A of the national standard GB/T21060-2007.

TABLE 1 stripper operating conditions and resin index comparisons for examples 1-8 and comparative examples 1-6

Detecting items	Stripper foam	Thermally aged whiteness/%)	Thermal stability time/min	Flow time/s	Apparent density/g/mL
						Example 1	Is normal	86.6	8.3	16.7	0.536
Example 2	Is normal	86.2	8	17.1	0.532
						Example 3	Much more	85.1	7.8	16.4	0.537
Example 4	Is normal	86.9	8.5	17.3	0.53
						Example 5	Much more	84.8	7.6	17.5	0.528
Example 6	Is normal	87	8.6	16.5	0.538
						Example 7	Is normal	87.2	8.7	16.4	0.539
Example 8	Is normal	86.0	7.8	16.5	0.538
						Comparative example 1	Multiple purpose	86.1	7.2	19.7	0.525
Comparative example 2	Is normal	82.6	5.2	19.6	0.526
						Comparative example 3	Is normal	82.6	5.3	18.1	0.539
Comparative example 4	Is normal	84.3	6.5	18.3	0.538
						Comparative example 5	Is normal	84.7	7	19.4	0.537
Comparative example 6	Much more	83.5	7.3	17.6	0.536

By comparing examples 1 to 8 with comparative examples 1 to 6, the following conclusions can be drawn:

1. comparison of example 1 with example 2 yields: the defoaming heat-stable composite auxiliary agent has different specific compositions, and polyvinyl chloride resin has different indexes of heat aging whiteness, heat stability time, flow time and apparent density.

2. Comparison of example 1 with examples 3 to 7 gives: the foam of the stripping tower is increased along with the reduction of the addition amount of the components of the polyether defoaming agent, and on the contrary, the foam is not obviously reduced; with the reduction of the addition of the antioxidant and the heat-stable composite auxiliary agent, the heat-aging whiteness and the heat-stable time are reduced, and otherwise, the heat-aging whiteness and the heat-stable time are slowly increased; as the amount of antistatic agent component added decreases, the flow time increases and the apparent density decreases, whereas the flow time decreases more slowly and the apparent density increases more slowly.

3. Comparison of comparative example 1 with example 1 gives: the polyether defoamer disclosed by the invention can obviously stabilize the foam working condition of the stripping tower under the combined action of other components, and can obviously improve the indexes of heat aging whiteness, heat stabilization time, flow time and apparent density of polyvinyl chloride resin.

4. Comparison of comparative example 2 with example 1 and comparative example 1 gives: the polyether defoamer component disclosed by the invention is independently used for preparing PVC resin, can obviously stabilize the foam working condition of the stripping tower, but cannot improve the heat aging whiteness, heat stabilization time, flow time and apparent density index of the PVC resin. But when the polyether defoamer and other components act together, the foam working condition of the stripping tower can be obviously stabilized, and the heat aging whiteness, the heat stabilization time, the flow time and the apparent density index of the polyvinyl chloride resin are obviously improved.

5. Comparison of comparative examples 4-5 with example 1 and comparative example 3 gives: comparative example 3 contains no antioxidant and thermal stabilizer component composite auxiliary agent, can stabilize stripping tower foam working condition and improve polyvinyl chloride resin fluidity and apparent density, but can not improve thermal aging whiteness and thermal stabilization time. The composite additive of comparative example 4 without an antioxidant component and the defoaming heat-stable composite additive of comparative example 5 without a heat stabilizer component can stabilize the foam working condition of the stripping tower and improve the fluidity and the apparent density of the polyvinyl chloride resin, but have little influence on the heat aging whiteness and the heat stabilization time of the resin. The performances of example 1 are all remarkably improved, which shows that the heat stabilizer and the antioxidant of the invention generate synergistic effect, thereby remarkably improving the heat aging whiteness and the heat stabilization time of the PVC resin.

6. Example 1 in comparison with examples 2-7 and comparative examples 1-5 gives: the composition and the addition amount of the defoaming heat-stable composite auxiliary agent in example 1 are preferred from the viewpoints of the improvement range of the effect and the economy.

7. Comparing example 7 with example 8, it can be seen that the heat stabilizer of the present application adopts a compounding manner of pentaerythritol and epoxidized soybean oil, and can significantly improve the heat aging whiteness and the heat stabilization time.

8. Comparing example 1 with comparative example 6, it can be seen that, when the polyether defoamer of the present application is applied to the preparation process of PVC resin, compared with other defoamers, the polyether defoamer can significantly stabilize the foaming condition of the stripping tower, and significantly improve the indexes of heat aging whiteness, heat stabilization time and flow time of the PVC resin.

The above detailed description is specific to one possible embodiment of the present invention, and the embodiment is not intended to limit the scope of the present invention, and all equivalent implementations or modifications without departing from the scope of the present invention should be included in the technical scope of the present invention.

Claims

1. The composite additive for polyvinyl chloride polymerization is characterized by comprising the following components in percentage by weight: 5-40% of polyether defoaming agent, 5-30% of antioxidant, 5-15% of heat stabilizer and 40-80% of antistatic agent.

2. The compounding aid of claim 1, wherein the polyether defoamer comprises one or more of polyoxypropylene ethylene oxide glycerol ether, polyoxyethylene polyoxypropylene pentaerythritol ether, and phenethyl phenol polyoxyethylene ether.

3. The compounding aid of claim 1, wherein the antioxidant comprises one or more of antioxidant 264, antioxidant 1024, antioxidant 1098, antioxidant 1076, and antioxidant 1010.

4. The compounding aid of claim 3, wherein the antioxidant comprises one or more of antioxidant 264, antioxidant 1098, and antioxidant 1010.

5. The compounding aid of claim 1, wherein the thermal stabilizer comprises one or more of calcium acetylacetonate, monopentaerythritol, dipentaerythritol, epoxidized soybean oil, and epoxidized castor oil.

6. The compounding aid of claim 5, wherein the thermal stabilizer comprises one or more of calcium acetylacetonate, monopentaerythritol, and epoxidized soybean oil.

7. The compounding aid according to claim 1, wherein the antistatic agent comprises one or more of methanol, ethanol, isopropanol, ethylene glycol, and glycerol, and preferably the antistatic agent comprises one or more of methanol, isopropanol, and ethanol.

8. Use of a compounding aid according to any one of claims 1 to 7 in the polymerisation of vinyl chloride monomer to produce polyvinyl chloride.

9. Use according to claim 8, wherein the compounding aid is added after the vinyl chloride monomer has been polymerized.

10. The use of claim 8 or 9, wherein the compounding aid is 0.026% -0.077% by mass of vinyl chloride monomer.