A lubricating agent for PVC plastic and preparation method thereof

Abstract

The invention relates to the technical field of plastic lubricants, and discloses a lubricating agent for PVC plastic and a preparation method thereof. The lubricating agent for PVC plastic of the invention has a core-shell structure, wherein the core layer is an organosilicon microsphere and the shell layer is a hyperbranched polymer; the organosilicon microsphere itself has excellent lubricating properties, but its dispersibility is limited, so the hyperbranched polymer is grafted on its surface to form a shell layer, thereby improving its dispersibility; and the polar groups contained in the hyperbranched polymer give it good compatibility with PVC, and the interaction between the polar groups and the PVC matrix is ​​utilized to further improve the lubricating properties of the lubricating agent; in addition, the introduction of heat-resistant groups also gives the lubricating agent excellent heat resistance.

Description

Technical Field

[0001] The invention relates to the technical field of plastic lubricants, and in particular to a lubricating auxiliary for PVC plastics and a preparation method thereof. Background Art

[0002] PVC plastic, or polyvinyl chloride plastic, is a widely used thermoplastic known for its excellent chemical resistance, weather resistance, mechanical strength and processing performance. However, there are some challenges in the processing of PVC, one of which is its high viscosity, which can lead to processing difficulties and product defects. In order to solve this problem, lubricating additives are usually used to improve the processing performance of PVC. In addition, considering the high temperature conditions required for the processing of PVC plastics, the lubricating additives are also required to have a certain heat resistance. The melt of PVC resin is usually very viscous. During molding, the melt must enter the mold cavity through the nozzle, gate and runner in a very short time. In order for the melt to fill the mold cavity smoothly in a very short time, it is critical to reduce the viscosity of the melt and improve the fluidity of the melt.

[0003] There are three types of lubricants for PVC: internal lubricants, external lubricants, and composite lubricants. Internal lubricants are usually small molecule organic compounds with polar groups. According to the principle of like dissolves like, internal lubricants have good compatibility with polar resins. External lubricants are generally non-polar or low-polarity organic compounds. The force between external lubricants and polar resins and metal surfaces is very small. Therefore, under high temperature and shear force, the film strength of external lubricants is low and it is easily damaged, affecting the effect of external lubricants. Composite lubricants are multi-purpose and have good lubrication effects. Therefore, it is necessary to develop a lubricating additive that has both the effects of internal lubricants and external lubricants, and also has a certain heat resistance. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a lubricating agent for PVC plastic and a preparation method thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for preparing a lubricating agent for PVC plastics comprises the following steps:

[0007] Step A1, adding methyltrimethoxysilane, 4-aminobutyltriethoxysilane and deionized water into a reactor, stirring and mixing evenly, and stirring at a speed of 300-600 rpm for 2 hours, and then adding ammonia water and stopping stirring, and then transferring the reactor to a 60° C. water bath, standing for 2-3 hours, and after the reaction is completed, centrifuging, washing, and drying to obtain silicone microspheres;

[0008] Step A2, adding organosilicon microspheres to N,N-dimethylacetamide and ultrasonically dispersing for 30 minutes, then raising the system temperature to 40-60° C., adding triglycidyl isocyanurate and mixing evenly, stirring for 8-12 hours under nitrogen conditions, and after the reaction is completed, distilling under reduced pressure, washing, and drying to obtain a core-shell precursor;

[0009] Step A3, dispersing the core-shell precursor in N,N-dimethylacetamide and stirring for 20 minutes, raising the system temperature to 45-55°C, adding tris(hydroxymethyl)aminomethane and stirring evenly under nitrogen, and continuing stirring for 3-5 hours. After the reaction is completed, distilling under reduced pressure, washing and drying to obtain a core-shell-hyperbranched precursor;

[0010] Step A4, adding a hyperbranched core-shell precursor, p-toluenesulfonic acid and N,N-dimethylformamide into a reactor and mixing evenly, then heating to 80-100°C, adding methyl paraben under nitrogen, then heating to 110-120°C, reacting for 3h, then adding N,N-dihydroxyethyl-3-aminopropionic acid methyl ester (self-made) and reacting for 6-8h, distilling under reduced pressure, cooling to room temperature, adding acetone and stirring for 10min, recrystallizing, filtering and drying to obtain a core-shell-hyperbranched polymer;

[0011] Step A5, under nitrogen conditions, adding the core-shell-hyperbranched polymer, p-toluenesulfonic acid and N,N-dimethylformamide into a reactor and mixing them evenly, heating to 140° C., adding lauric acid and refluxing for 3-5 hours, and after the reaction is completed, performing reduced pressure distillation to obtain a composite lubricating agent;

[0012] Further, in step A1, the usage ratio of methyltrimethoxysilane, 4-aminobutyltriethoxysilane, deionized water and ammonia water is 0.25-1 mol: 0.01-0.5 mol: 40-160 mL: 0.05-0.2 mL;

[0013] Further, in step A2, the usage ratio of the organosilicon microspheres, N,N-dimethylacetamide and triglycidyl isocyanurate is 1 g:100 mL:0.01-0.05 mol;

[0014] Further, in step A3, the ratio of the core-shell precursor, N,N-dimethylacetamide and tris(hydroxymethyl)aminomethane is 1-3 g:100 mL:0.01-0.05 mol;

[0015] Further, in step A4, the ratio of the hyperbranched core-shell precursor, p-toluenesulfonic acid, N,N-dimethylformamide, methyl paraben, methyl N,N-dihydroxyethyl-3-aminopropionate and acetone is 1-3 g: 0.36-1.8 g: 300 mL: 0.03-0.15 mol: 0.09-0.45 mol: 100 mL;

[0016] Furthermore, in step A5, the usage ratio of the core-shell-hyperbranched polymer, p-toluenesulfonic acid, N,N-dimethylformamide and lauric acid is 1 g: 0.12-0.36 g: 100 mL: 0.1-0.3 mol.

[0017] In a second aspect, the present invention also includes a lubricating agent for PVC plastics prepared by the above preparation method;

[0018] Furthermore, the lubricating agent has a core-shell structure, wherein the core layer is organic silicon microspheres and the shell layer is a hyperbranched polymer.

[0019] Beneficial effects of the present invention:

[0020] The lubricating agent for PVC plastics of the present invention has a core-shell structure, wherein the core layer is an organosilicon microsphere and the shell layer is a hyperbranched polymer; the organosilicon microsphere itself has excellent lubricating performance, but its dispersibility is limited, so the hyperbranched polymer is grafted onto the surface of the organosilicon microsphere to form a shell layer, thereby improving its dispersibility; the polar groups contained in the hyperbranched polymer give it good compatibility with PVC, and the interaction between the polar groups and the PVC matrix is ​​utilized to further improve the lubricating performance of the lubricating agent; in addition, the introduction of the heat-resistant group also gives the lubricating agent excellent heat resistance.

[0021] In the lubricating agent, methyltrimethoxysilane and 4-aminobutyltriethoxysilane are first used as raw materials to synthesize silicone microspheres containing -NH2 on the surface; then the core-shell precursor is synthesized by the ring-opening reaction between the epoxy group in triglycidyl isocyanurate and the amino group on the surface of the silicone microsphere; the amino group in trihydroxymethylaminomethane and the epoxy group on the surface of the core-shell precursor are further subjected to the ring-opening reaction to synthesize the core-shell-hyperbranched precursor; the hydroxyl group in the core-shell-hyperbranched precursor and the ester group in the intermediate product are subjected to ester exchange reaction to synthesize the core-shell-hyperbranched polymer; finally, the lubricating agent is synthesized by the esterification reaction between the hydroxyl group in the core-shell-hyperbranched polymer and the carboxyl group in lauric acid. After the lubricating agent is applied to PVC plastic, it has excellent lubricating properties and excellent heat resistance, which can meet the high temperature environment required for PVC plastic processing. The lubricating agent has a unique core-shell structure, the core layer is silicone microspheres, and the shell layer is hyperbranched polymers. Through the synergistic effect between the two, a better lubrication effect is achieved. Among them, silicone microspheres have a good lubrication effect in the synthesis of PVC plastics, but their dispersibility is poor. Therefore, the surface is modified to synthesize hyperbranched polymers, which improves their dispersibility in the PVC matrix and further improves the lubrication effect. Hyperbranched polymers have a highly differentiated branched structure, which makes them have excellent dispersibility in the matrix. At the same time, a large number of polar groups are introduced into the hyperbranched polymer branches, such as long-chain alkyl groups. , ester group, isocyanurate ring, etc., and before plasticization, some polar groups have a strong affinity with the polar nodes in the PVC resin. After chemical adsorption, complex bonds are formed, and the combination is in dynamic equilibrium, which weakens the friction between the resin segments. After plasticization, the polar groups weaken the interaction between molecules and molecular segments in the melt, making the resin melt easy to flow, reducing the plasticization torque, reducing the melt viscosity, and playing a role of internal lubrication; the side chains in the hyperbranched polymer can also be entangled with the main chain of the PVC molecule, avoiding the migration and precipitation of traditional lubricants due to processing, and reducing production costs; in addition, heat-resistant groups (isocyanurate rings) are introduced into the hyperbranched polymer to improve the heat resistance of the lubricating agent, and the introduction of the benzene ring structure also gives the PVC matrix a certain UV resistance. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0023] A method for preparing a lubricating agent for PVC plastics comprises the following steps:

[0024] Step A1, 0.25 mol of methyltrimethoxysilane, 0.01 mol of 4-aminobutyltriethoxysilane and 40 mL of deionized water were added into a reactor and stirred to mix evenly, and stirred at a speed of 300 rpm for 2 h, and then 0.05 mL of ammonia water was added and the stirring was stopped, and then the reactor was transferred to a 60° C. water bath and allowed to stand for 2 h. After the reaction was completed, the reaction was centrifuged, washed and dried to obtain organosilicon microspheres;

[0025] Step A2, add 1g of organosilicon microspheres to 100mL of N,N-dimethylacetamide and ultrasonically disperse for 30min, then increase the system temperature to 40°C, add 0.01mol of triglycidyl isocyanurate and mix evenly, stir for 8h under nitrogen, and after the reaction is completed, distill under reduced pressure, wash and dry to obtain a core-shell precursor;

[0026] Step A3, disperse 1 g of the core-shell precursor in 100 mL of N, N-dimethylacetamide and stir for 20 min, raise the system temperature to 45 ° C, add 0.01 mol of tris(hydroxymethyl)aminomethane under nitrogen, mix and stir evenly, and continue stirring for 3 h. After the reaction is completed, distill under reduced pressure, wash and dry to obtain a core-shell-hyperbranched precursor;

[0027] Step A4, 1 g of a hyperbranched core-shell precursor, 0.36 g of p-toluenesulfonic acid and 300 mL of N, N-dimethylformamide were added to a reactor and mixed evenly, then the temperature was raised to 80°C, 0.03 mol of methyl paraben was added under nitrogen, and then the temperature was raised to 110°C for reaction for 3 h, and then 0.09 mol of N, N-dihydroxyethyl-3-aminopropionic acid methyl ester (self-made) was added for reaction for 6 h, and then the mixture was distilled under reduced pressure, cooled to room temperature, 100 mL of acetone was added, stirred for 10 min, recrystallized, filtered and dried to obtain a core-shell-hyperbranched polymer;

[0028] Step A5: Under nitrogen conditions, 1 g of core-shell-hyperbranched polymer, 0.12 g of p-toluenesulfonic acid and 100 mL of N,N-dimethylformamide were added into a reactor and mixed evenly. The mixture was heated to 140° C., and 0.1 mol of lauric acid was added and refluxed for 3 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain a lubricating agent. Example 2

[0029] A method for preparing a lubricating agent for PVC plastics comprises the following steps:

[0030] Step A1, 0.5 mol of methyltrimethoxysilane, 0.1 mol of 4-aminobutyltriethoxysilane and 80 mL of deionized water were added into a reactor and stirred to mix evenly, and stirred at a speed of 400 rpm for 2 h, and then 0.1 mL of ammonia water was added and the stirring was stopped, and then the reactor was transferred to a 60° C. water bath and allowed to stand for 2.5 h. After the reaction was completed, the reaction was centrifuged, washed and dried to obtain silicone microspheres;

[0031] Step A2, add 1g of organosilicon microspheres to 100mL of N,N-dimethylacetamide and ultrasonically disperse for 30min, then increase the system temperature to 50°C, add 0.02mol of triglycidyl isocyanurate and mix evenly, stir for 9 under nitrogen, after the reaction is completed, distill under reduced pressure, wash and dry to obtain a core-shell precursor;

[0032] Step A3, disperse 2 g of the core-shell precursor in 100 mL of N, N-dimethylacetamide and stir for 20 min, raise the system temperature to 50 ° C, add 0.02 mol of tris(hydroxymethyl)aminomethane under nitrogen, mix and stir evenly, and continue stirring for 4 h. After the reaction is completed, distill under reduced pressure, wash and dry to obtain a core-shell-hyperbranched precursor;

[0033] Step A4, 2 g of hyperbranched core-shell precursor, 0.72 g of p-toluenesulfonic acid and 300 mL of N, N-dimethylformamide were added to the reactor and mixed evenly, then the temperature was raised to 90 ° C., 0.06 mol of methyl paraben was added under nitrogen, and then the temperature was raised to 115 ° C., reacted for 3 h, and then 0.18 mol of N, N-dihydroxyethyl-3-aminopropionic acid methyl ester (self-made) was added and reacted for 7 h, then distilled under reduced pressure, cooled to room temperature, added 100 mL of acetone and stirred for 10 min, recrystallized, filtered and dried to obtain a core-shell-hyperbranched polymer;

[0034] Step A5: Under nitrogen conditions, 1 g of core-shell-hyperbranched polymer, 0.24 g of p-toluenesulfonic acid and 100 mL of N,N-dimethylformamide were added into a reactor and mixed evenly. The mixture was heated to 140° C., and 0.2 mol of lauric acid was added and refluxed for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain a lubricating agent. Example 3

[0035] A method for preparing a lubricating agent for PVC plastics comprises the following steps:

[0036] Step A1, 0.75 mol of methyltrimethoxysilane, 0.3 mol of 4-aminobutyltriethoxysilane and 120 mL of deionized water were added to a reactor and stirred to mix evenly, and stirred at a speed of 500 rpm for 2 h, and then 0.15 mL of ammonia water was added and the stirring was stopped, and then the reactor was transferred to a 60° C. water bath and allowed to stand for 2.5 h. After the reaction was completed, centrifugation, washing and drying were performed to obtain silicone microspheres;

[0037] Step A2, add 1g of organosilicon microspheres to 100mL of N,N-dimethylacetamide and ultrasonically disperse for 30min, then increase the system temperature to 55°C, add 0.03mol of triglycidyl isocyanurate and mix evenly, stir for 10h under nitrogen, and after the reaction is completed, distill under reduced pressure, wash and dry to obtain a core-shell precursor;

[0038] Step A3, disperse 2.5g of the core-shell precursor in 100mL of N,N-dimethylacetamide and stir for 20min, raise the system temperature to 45-55°C, add 0.03mol of tris(hydroxymethyl)aminomethane under nitrogen, mix and stir evenly, and continue stirring for 4h. After the reaction is completed, distill under reduced pressure, wash and dry to obtain a core-shell-hyperbranched precursor;

[0039] Step A4, 2.5 g of a hyperbranched core-shell precursor, 1.2 g of p-toluenesulfonic acid and 300 mL of N, N-dimethylformamide were added to a reactor and mixed evenly, then the temperature was raised to 90 ° C., 0.09 mol of methyl paraben was added under nitrogen, and then the temperature was raised to 120 ° C. and reacted for 3 h, and then 0.27 mol of N, N-dihydroxyethyl-3-aminopropionic acid methyl ester (self-made) was added and reacted for 6-8 h, and then distilled under reduced pressure, cooled to room temperature, 100 mL of acetone was added, stirred for 10 min, recrystallized, filtered, and dried to obtain a core-shell-hyperbranched polymer;

[0040] Step A5: Under nitrogen conditions, 1 g of core-shell-hyperbranched polymer, 0.36 g of p-toluenesulfonic acid and 100 mL of N,N-dimethylformamide were added into a reactor and mixed evenly. The mixture was heated to 140° C., and 0.25 mol of lauric acid was added and refluxed for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain a lubricating agent. Example 4

[0041] A method for preparing a lubricating agent for PVC plastics comprises the following steps:

[0042] Step A1, 1 mol of methyltrimethoxysilane, 0.5 mol of 4-aminobutyltriethoxysilane and 160 mL of deionized water were added into a reactor and stirred to mix evenly, and stirred at a speed of 600 rpm for 2 h, and then 0.2 mL of ammonia water was added and the stirring was stopped, and then the reactor was transferred to a 60° C. water bath and allowed to stand for 3 h. After the reaction was completed, the reaction was centrifuged, washed and dried to obtain silicone microspheres;

[0043] Step A2, add 1g of organosilicon microspheres to 100mL of N,N-dimethylacetamide and ultrasonically disperse for 30min, then increase the system temperature to 60°C, add 0.05mol of triglycidyl isocyanurate and mix evenly, stir for 12h under nitrogen, and after the reaction is completed, distill under reduced pressure, wash and dry to obtain a core-shell precursor;

[0044] Step A3, disperse 3 g of the core-shell precursor in 100 mL of N, N-dimethylacetamide and stir for 20 min, raise the system temperature to 55 ° C, add 0.05 mol of tris(hydroxymethyl)aminomethane under nitrogen, mix and stir evenly, and continue stirring for 5 h. After the reaction is completed, distill under reduced pressure, wash and dry to obtain a core-shell-hyperbranched precursor;

[0045] Step A4, 3g of hyperbranched core-shell precursor, 1.8g of p-toluenesulfonic acid and 300mL of N,N-dimethylformamide were added to the reactor and mixed evenly, then the temperature was raised to 100°C, 0.15mol of methyl paraben was added under nitrogen, and then the temperature was raised to 120°C, reacted for 3h, and then 0.45mol of N,N-dihydroxyethyl-3-aminopropionic acid methyl ester (self-made) was added and reacted for 6-8h, and then distilled under reduced pressure, cooled to room temperature, added 100mL of acetone and stirred for 10min, recrystallized, filtered and dried to obtain a core-shell-hyperbranched polymer;

[0046] Step A5: Under nitrogen conditions, 1 g of core-shell-hyperbranched polymer, 0.36 g of p-toluenesulfonic acid and 100 mL of N,N-dimethylformamide were added into a reactor and mixed evenly. The mixture was heated to 140° C., and 0.3 mol of lauric acid was added and refluxed for 5 h. After the reaction was completed, the mixture was distilled under reduced pressure to obtain a lubricating agent.

[0047] Comparative Example 1

[0048] This comparative example is a lubricating auxiliary agent, which is a commercially available lubricant EBS.

[0049] Comparative Example 2

[0050] This comparative example is a lubricating agent, which is the organosilicon microspheres prepared by Example 4.

[0051] Comparative Example 3

[0052] This comparative example is a lubricating agent, which is prepared by the following steps:

[0053] Step A1, add 0.05 mol of tris(hydroxymethyl)aminomethane to 100 mL of N,N-dimethylacetamide and stir for 20 min, raise the system temperature to 100 ° C, slowly add 0.017 mol of triglycidyl isocyanurate under nitrogen and mix and stir evenly, lower the system temperature to 55 ° C, and continue stirring for 5 h. After the reaction is completed, distill under reduced pressure, wash and dry to obtain a hyperbranched precursor;

[0054] Step A2, 3 g of hyperbranched precursor, 1.8 g of p-toluenesulfonic acid and 300 mL of N, N-dimethylformamide were added to a reactor and mixed evenly, then the temperature was raised to 100 ° C., 0.15 mol of methyl paraben was added under nitrogen, and then the temperature was raised to 120 ° C., reacted for 3 h, and then 0.45 mol of N, N-dihydroxyethyl-3-aminopropionic acid methyl ester (self-made) was added and reacted for 8 h, then distilled under reduced pressure, cooled to room temperature, added 100 mL of acetone and stirred for 10 min, recrystallized, filtered and dried to obtain a core-shell-hyperbranched polymer;

[0055] Step A3, under nitrogen conditions, add 1 g of core-shell-hyperbranched polymer, 0.36 g of p-toluenesulfonic acid and 100 mL of N,N-dimethylformamide into a reactor and mix well, heat to 140° C., add 0.3 mol of lauric acid and reflux for 5 h. After the reaction is completed, vacuum distillation is performed to obtain a lubricating agent.

[0056] The lubricating agents of Examples 1-4 and Comparative Examples 1-3 were subjected to performance tests:

[0057] The lubricating agent prepared was added to PVC at a mass ratio of 0.5% during PVC molding, hot melted, mixed, and extruded using a Φ20 single screw extruder to perform an extrusion test and observe the extrusion surface smoothness. Extrusion conditions: temperature zone 1, 80°C; zone 2, 150°C; zone 3, 154°C; die head, 150°C; speed, 40r / min.

[0058] 2) The prepared lubricating agent is subjected to TGA thermal decomposition temperature detection to characterize the heat resistance.

[0059] The test results are shown in the following table:

[0060]

[0061] It can be seen from the above table that the lubricating agent prepared by the present invention has excellent lubricating effect after being applied to PVC plastic, the extrusion amount is 43.6g / min-48.3g / min, and the extruded surface is very smooth, bright and reflective; the TGA thermal decomposition temperature test shows that the thermal decomposition temperature is 406°C-415°C, and it has good heat resistance.

[0062] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a lubricating agent for PVC plastic, characterized in that: The method comprises the following steps: Step A1, adding methyltrimethoxysilane, 4-aminobutyltriethoxysilane and deionized water into a reactor, stirring and mixing evenly, and stirring at a speed of 300-600 rpm for 2 hours, and then adding ammonia water and stopping stirring, and then transferring the reactor to a 60° C. water bath, standing for 2-3 hours, and after the reaction is completed, centrifuging, washing, and drying to obtain silicone microspheres; Step A2, adding organosilicon microspheres to N,N-dimethylacetamide and ultrasonically dispersing for 30 minutes, then raising the system temperature to 40-60° C., adding triglycidyl isocyanurate and mixing evenly, stirring for 8-12 hours under nitrogen conditions, and after the reaction is completed, distilling under reduced pressure, washing, and drying to obtain a core-shell precursor; Step A3, dispersing the core-shell precursor in N,N-dimethylacetamide and stirring for 20 minutes, raising the system temperature to 45-55°C, adding tris(hydroxymethyl)aminomethane and stirring evenly under nitrogen, and continuing stirring for 3-5 hours. After the reaction is completed, distilling under reduced pressure, washing and drying to obtain a core-shell-hyperbranched precursor; Step A4, adding a hyperbranched core-shell precursor, p-toluenesulfonic acid and N,N-dimethylformamide into a reactor and mixing evenly, then heating to 80-100° C., adding methyl paraben under nitrogen, then heating to 110-120° C., reacting for 3 h, then adding N,N-dihydroxyethyl-3-aminopropionic acid methyl ester and reacting for 6-8 h, distilling under reduced pressure, cooling to room temperature, adding acetone and stirring for 10 min, recrystallizing, filtering and drying to obtain a core-shell-hyperbranched polymer; Step A5: under nitrogen conditions, add the core-shell-hyperbranched polymer, p-toluenesulfonic acid and N,N-dimethylformamide into a reactor and mix them evenly. Heat to 140° C., add lauric acid and reflux for 3-5 hours. After the reaction is completed, perform vacuum distillation to obtain a composite lubricating agent.

2. The method for preparing a lubricating agent for PVC plastic according to claim 1, characterized in that: In step A1, the usage ratio of methyltrimethoxysilane, 4-aminobutyltriethoxysilane, deionized water and ammonia water is 0.25-1 mol: 0.01-0.5 mol: 40-160 mL: 0.05-0.2 mL.

3. The method for preparing a lubricating agent for PVC plastic according to claim 1, characterized in that: In step A2, the usage ratio of the organosilicon microspheres, N,N-dimethylacetamide and triglycidyl isocyanurate is 1 g:100 mL:0.01-0.05 mol.

4. The method for preparing a lubricating agent for PVC plastic according to claim 1, characterized in that: In step A3, the usage ratio of the core-shell precursor, N,N-dimethylacetamide and tris(hydroxymethyl)aminomethane is 1-3 g:100 mL:0.01-0.05 mol.

5. The method for preparing a lubricating agent for PVC plastic according to claim 1, characterized in that: In step A4, the amount ratio of the hyperbranched core-shell precursor, p-toluenesulfonic acid, N,N-dimethylformamide, methyl paraben, methyl N,N-dihydroxyethyl-3-aminopropionate and acetone is 1-3 g: 0.36-1.8g: 300mL: 0.03-0.15mol: 0.09-0.45mol: 100mL.

6. The method for preparing a lubricating agent for PVC plastic according to claim 1, characterized in that: In step A5, the usage ratio of the core-shell-hyperbranched polymer, p-toluenesulfonic acid, N,N-dimethylformamide and lauric acid is 1 g: 0.12-0.36 g: 100 mL: 0.1-0.3 mol.

7. A lubricating agent for PVC plastics prepared by the preparation method according to any one of claims 1 to 6.

8. The method for preparing a lubricating agent for PVC plastic according to claim 1, characterized in that: The lubricating auxiliary agent has a core-shell structure, the core layer is organic silicon microspheres, and the shell layer is a hyperbranched polymer.

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