A styrene-acrylonitrile-maleic anhydride copolymer masterbatch, a preparation method and application thereof in modified polyvinyl chloride

Abstract

The application belongs to the technical field of high polymer materials, and particularly relates to a styrene-acrylonitrile-maleic anhydride copolymer masterbatch, a preparation method thereof and application of the masterbatch in modified polyvinyl chloride. The styrene-acrylonitrile-maleic anhydride copolymer masterbatch is obtained by melt mixing of a styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder and silicon carbide fiber. The spherical graphite powder and the silicon carbide fiber can form a 0-1 type three-dimensional space skeleton structure, which is beneficial to stabilizing the PVC matrix when heated. The maleic anhydride in the styrene-acrylonitrile-maleic anhydride copolymer has a strong interaction with the spherical graphite powder and the silicon carbide fiber, which can improve the compatibility of the spherical graphite powder and the silicon carbide fiber in the PVC system. The silicon carbide fiber can hinder the movement of the PVC chain segment, thereby improving the glass transition temperature of the PVC chain segment. The three components have a synergistic effect, which effectively improves the heat resistance and thermal stability of the polyvinyl chloride.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology. More specifically, it relates to a styrene-acrylonitrile-maleic anhydride copolymer masterbatch, its preparation method, and its application in modified polyvinyl chloride. Background Technology

[0002] Polyvinyl chloride (PVC) is one of the five major general-purpose synthetic resins with excellent comprehensive performance, ranking second in production volume after polyethylene. PVC possesses advantages such as light weight, ease of processing, good flame retardancy, and mechanical properties, making it widely applicable across various industries, from daily life to high-tech fields like aerospace. PVC is produced by the free radical polymerization of vinyl chloride monomer. Under heat and shear stress, it easily loses hydrogen chloride, resulting in poor thermal stability and processing performance, which limits its applications. Therefore, modifying PVC with different modifiers is a key focus of industry research.

[0003] There has been considerable research on the modification and application of polyvinyl chloride (PVC). For example, Chinese patent application CN105694284A discloses the use of nano-calcium carbonate and nano-graphite powder as thermal conductivity aids to improve the thermal conductivity of PVC, thereby achieving rapid heat transfer between the inside and outside of the pipe. Chinese patent application CN104861359A discloses a carbon fiber-filled modified PVC plastic and its preparation method. The resulting composite PVC plastic, modified with carbon fiber, possesses advantages such as high strength, high flame retardancy, high temperature resistance, low density, and good chemical stability. Chinese patent application CN10508624... 0A discloses a method for preparing styrene-maleic anhydride-acrylonitrile copolymer-modified polyvinyl chloride (PVC). The method involves placing a styrene-maleic anhydride-acrylonitrile copolymer modifier in a two-roll mill and performing a thin-roll milling process at 170–180°C to obtain the modifier. This modifier is then added to a uniformly mixed mixture of PVC, a heat stabilizer, and a plasticizer, and mixed and milled again. The mixture is then hot-pressed into sheets, followed by cold pressing to obtain the modified PVC composite material. The styrene-maleic anhydride-acrylonitrile copolymer modifier obtained by this method is beneficial for improving the thermal stability, yellowing resistance, and processability of PVC. However, the compatibility of the aforementioned nano-graphite powder or carbon fiber with PVC is poor, preventing the full realization of its modification effect. The effect of the styrene-maleic anhydride-acrylonitrile modifier alone on improving the heat resistance of PVC is limited. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings and deficiencies of the prior art, such as the poor compatibility between nano-graphite powder or carbon fiber and polyvinyl chloride, which prevents the full utilization of their modification effect, and the limited effect of styrene-maleic anhydride-acrylonitrile modifier on improving the heat resistance of polyvinyl chloride. The main purpose is to provide a styrene-acrylonitrile-maleic anhydride copolymer masterbatch.

[0005] A secondary objective of this invention is to provide a method for preparing the styrene-acrylonitrile-maleic anhydride copolymer masterbatch.

[0006] Another object of the present invention is to provide the application of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch.

[0007] Another object of the present invention is to provide a polyvinyl chloride composite material.

[0008] The purpose of this invention is to provide a method for preparing the polyvinyl chloride composite material.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] This invention protects a styrene-acrylonitrile-maleic anhydride copolymer masterbatch, which is prepared from styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder and silicon carbide fiber;

[0011] The mass ratio of the styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder, and silicon carbide fiber is 1:(0.025–0.75):(0.075–1.25). Under these parameters, the three components can fully exert their synergistic effect.

[0012] Highly crystalline zero-dimensional spherical graphite powder and one-dimensional silicon carbide fibers can form a three-dimensional spatial skeleton structure of type 0-1. This skeleton structure is beneficial for stabilizing the polyvinyl chloride (PVC) matrix when heated, so that the PVC matrix can remain stable when heated. The styrene-acrylonitrile-maleic anhydride copolymer exhibits good compatibility with polyvinyl chloride (PVC). Furthermore, the maleic anhydride it contains strongly interacts with spherical graphite powder and silicon carbide fibers, enhancing their compatibility within the PVC system. The high aspect ratio of the silicon carbide fibers also hinders the movement of PVC chain segments, thereby increasing its glass transition temperature (heat resistance). The styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared from these components overcomes the shortcomings of poor compatibility between individual nano-graphite powder, silicon carbide fibers, and PVC, and also addresses the limited effect of the styrene-acrylonitrile-maleic anhydride copolymer alone on improving the heat resistance of PVC. The synergistic effect of these three components significantly promotes the improvement of PVC's thermal stability, effectively enhancing its heat resistance and thermal stability.

[0013] Preferably, the mass ratio of the styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder, and silicon carbide fiber is 1:(0.1-0.75):(0.1-1.25).

[0014] Furthermore, the styrene-acrylonitrile-maleic anhydride copolymer contains 25-35 wt% styrene, 60-70 wt% acrylonitrile, and 3-8 wt% maleic anhydride by mass percentage, respectively. The styrene-acrylonitrile-maleic anhydride copolymer obtained under these parameters exhibits good compatibility with polyvinyl chloride.

[0015] Preferably, the styrene-acrylonitrile-maleic anhydride copolymer contains 30 wt% styrene, 65 wt% acrylonitrile, and 5 wt% maleic anhydride by mass percentage.

[0016] Furthermore, the average molecular weight of the styrene-acrylonitrile-maleic anhydride copolymer is 40,000 to 60,000.

[0017] Furthermore, the spherical graphite powder has a particle size of 20–60 μm. Under these parameters, the spherical graphite powder readily forms a three-dimensional spatial framework structure of type 0-1 with silicon carbide fibers.

[0018] Furthermore, the aspect ratio of the silicon carbide fiber is 100–200:1. Under these parameters, the silicon carbide fiber readily forms a three-dimensional spatial framework structure of type 0-1 with spherical graphite powder.

[0019] The present invention also protects a method for preparing the styrene-acrylonitrile-maleic anhydride copolymer masterbatch, comprising the following steps: thoroughly mixing the styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder, and silicon carbide fiber, melting and blending at 190-210°C, and cooling to obtain the styrene-acrylonitrile-maleic anhydride copolymer masterbatch.

[0020] Furthermore, the rotational speed for thorough mixing is 400–500 rpm / s, and the time is 5–15 s.

[0021] Furthermore, the melt blending time is 10–20 min.

[0022] Furthermore, the mixed raw materials are dried before being thoroughly mixed.

[0023] Furthermore, the drying temperature is 50–90°C.

[0024] The present invention also protects the use of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch in modified polyvinyl chloride.

[0025] This invention also protects a polyvinyl chloride composite material, which is mainly made of the following raw materials in parts by weight: 100 parts of polyvinyl chloride, 24-65 parts of the above-mentioned styrene-acrylonitrile-maleic anhydride copolymer masterbatch, 1-10 parts of calcium-zinc heat stabilizer, 5-20 parts of magnesium hydroxide, 5-20 parts of calcium carbonate, 1-10 parts of titanium dioxide and 1-10 parts of stearic acid.

[0026] Furthermore, the average degree of polymerization of the polyvinyl chloride is 900 to 1200.

[0027] In the aforementioned polyvinyl chloride composite material, the addition of calcium carbonate powder is to enhance the flexural strength of the composite system; magnesium hydroxide, as an adsorbent, absorbs harmful gases such as hydrogen chloride, thereby reducing the release of these gases. Magnesium hydroxide serves two purposes: firstly, it absorbs and decomposes the byproducts such as hydrogen chloride generated after the substitution reaction; secondly, it acts as a flame retardant, providing flame retardancy and heat resistance.

[0028] The present invention also protects the preparation method of the polyvinyl chloride composite material, comprising the following steps: thoroughly mixing the raw materials, melting and blending them at 165-190°C, cutting and molding them, and cooling them to obtain the polyvinyl chloride composite material.

[0029] Furthermore, the molding temperature is 180–190°C.

[0030] Furthermore, the shearing refers to shearing the melt-blended material into particles with a diameter of 10-20 mm.

[0031] Furthermore, the mixed raw materials are dried before being thoroughly mixed.

[0032] Furthermore, the drying temperature is 50–90°C.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The styrene-acrylonitrile-maleic anhydride copolymer masterbatch of this invention is obtained by melt mixing of styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder, and silicon carbide fibers. The spherical graphite powder and silicon carbide fibers can form a three-dimensional spatial framework structure of type 0-1, which helps stabilize the polyvinyl chloride (PVC) body when heated. Furthermore, the maleic anhydride in the styrene-acrylonitrile-maleic anhydride copolymer has strong interactions with both the spherical graphite powder and silicon carbide fibers, improving their compatibility with the PVC system. Additionally, the silicon carbide fibers can hinder the movement of PVC chain segments, thereby increasing its glass transition temperature. These three components work synergistically to effectively improve the heat resistance and thermal stability of PVC. Detailed Implementation

[0035] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0036] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0037] Nano-graphite powder: Qingdao Teda Tianrun Carbon Materials Co., Ltd.;

[0038] Graphite flakes: Sinopharm Group;

[0039] Silicon carbide fiber: Aladdin reagent.

[0040] Example 1: Preparation of a styrene-acrylonitrile-maleic anhydride copolymer masterbatch and a polyvinyl chloride composite material

[0041] A styrene-acrylonitrile-maleic anhydride copolymer masterbatch has the following raw material components and weight proportions: 20 parts styrene-acrylonitrile-maleic anhydride copolymer, 1 part spherical graphite powder, and 4 parts silicon carbide fiber.

[0042] The preparation of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch includes the following steps: weighing the raw materials according to the formula, drying them in a constant temperature drying oven at 80℃, mixing them evenly with a high-speed mixer, and then melting and blending them in a torque rheometer to prepare a styrene-acrylonitrile-maleic anhydride copolymer masterbatch containing ductile graphite powder and silicon carbide fiber.

[0043] The melting temperature was 195℃, the rotation speed was 40 rpm / min, and the melting time was 15 min.

[0044] The conditions for uniform mixing in a high-speed mixer are: speed of 400-500 rpm / s and mixing time of 15s.

[0045] A high thermal stability polyvinyl chloride composite material, the raw material components and weight ratios are as follows: 100 parts polyvinyl chloride, the styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared above, 2 parts calcium-zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0046] The polyvinyl chloride composite material is prepared by the following steps:

[0047] S1. Dry polyvinyl chloride, magnesium hydroxide, calcium carbonate, stearic acid, calcium zinc heat stabilizer and titanium dioxide in a constant temperature drying oven at 80℃ for later use, and then mix them evenly with a high-speed mixer to obtain a mixed powder.

[0048] S2. The mixed powder obtained in step S2 is placed in a torque rheometer and melt-blended with the styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared above. Then, the mixed material is promptly sheared into large particles to obtain a polyvinyl chloride composite material with improved thermal stability.

[0049] S3. Mold the shredded particles obtained in step S2, and then press the molded material into a thin plate.

[0050] The silicon carbide fibers have an average aspect ratio of 100:1, and the spherical graphite powder has an average particle size of 50 μm.

[0051] The conditions for uniform mixing in the high-speed mixer are: speed of 400-500 rpm / s and mixing time of 15s.

[0052] In step S2, the melting temperature is 185℃, the rotation speed is 40 rpm / min, and the time is set to 10 min.

[0053] In step S3, the molding temperature is 185℃, the pressure is 12MPa, and the time is 12min.

[0054] Example 2: Preparation of a styrene-acrylonitrile-maleic anhydride copolymer masterbatch and a polyvinyl chloride composite material

[0055] The difference from Example 1 is that the amount of spherical graphite powder and silicon carbide fiber added is different, with 5 and 10 parts respectively.

[0056] A styrene-acrylonitrile-maleic anhydride copolymer masterbatch has the following raw material components and weight proportions: 20 parts of styrene-acrylonitrile-maleic anhydride copolymer, 5 parts of spherical graphite powder, and 10 parts of silicon carbide fiber.

[0057] The preparation of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is described in Example 1.

[0058] A high thermal stability polyvinyl chloride composite material, the raw material components and weight ratios are as follows: 100 parts polyvinyl chloride, the styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared above, 2 parts calcium-zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0059] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0060] Example 3: Preparation of a styrene-acrylonitrile-maleic anhydride copolymer masterbatch and a polyvinyl chloride composite material

[0061] The difference from Example 1 is that the amount of calcium-zinc heat stabilizer added is different, and the amount added is 4 parts.

[0062] A styrene-acrylonitrile-maleic anhydride copolymer masterbatch has the following raw material components and weight proportions: 20 parts styrene-acrylonitrile-maleic anhydride copolymer, 1 part spherical graphite powder, and 4 parts silicon carbide fiber.

[0063] The preparation of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is described in Example 1.

[0064] A high thermal stability polyvinyl chloride composite material, the raw material components and weight ratios are as follows: 100 parts polyvinyl chloride, the styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared above, 4 parts calcium-zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0065] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0066] Example 4: Preparation of a styrene-acrylonitrile-maleic anhydride copolymer masterbatch and a polyvinyl chloride composite material

[0067] The difference from Example 1 is that the amounts of spherical graphite powder, silicon carbide fiber and calcium-zinc heat stabilizer added are different, with addition amounts of 5, 10 and 4 parts respectively.

[0068] A styrene-acrylonitrile-maleic anhydride copolymer masterbatch has the following raw material components and weight proportions: 20 parts of styrene-acrylonitrile-maleic anhydride copolymer, 5 parts of spherical graphite powder, and 10 parts of silicon carbide fiber.

[0069] The preparation of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is described in Example 1.

[0070] A high thermal stability polyvinyl chloride composite material, the raw material components and weight ratios are as follows: 100 parts polyvinyl chloride, the styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared above, 4 parts calcium-zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0071] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0072] Comparative Example 1: A polyvinyl chloride composite material

[0073] The difference from Example 1 is that the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is replaced with an equal amount of styrene-acrylonitrile-maleic anhydride copolymer.

[0074] A polyvinyl chloride composite material, the raw material components and weight proportions are as follows: 100 parts polyvinyl chloride, 25 parts styrene-acrylonitrile-maleic anhydride copolymer, 2 parts calcium-zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0075] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0076] Comparative Example 2: Preparation of a styrene-acrylonitrile-maleic anhydride copolymer masterbatch and a polyvinyl chloride composite material

[0077] The difference from Example 1 is that no silicon carbide fiber is added to the styrene-acrylonitrile-maleic anhydride copolymer masterbatch.

[0078] A styrene-acrylonitrile-maleic anhydride copolymer masterbatch has the following raw material components and weight ratios: 24 parts of styrene-acrylonitrile-maleic anhydride copolymer and 1 part of spherical graphite powder.

[0079] The preparation of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is described in Example 1.

[0080] A polyvinyl chloride composite material, the raw material components and weight proportions of which are as follows: 100 parts polyvinyl chloride, the styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared above, 2 parts calcium-zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0081] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0082] Comparative Example 3: Preparation of a styrene-acrylonitrile-maleic anhydride copolymer masterbatch and a polyvinyl chloride composite material

[0083] The difference from Example 1 is that spherical graphite powder is not added to the styrene-acrylonitrile-maleic anhydride copolymer masterbatch.

[0084] A styrene-acrylonitrile-maleic anhydride copolymer masterbatch, the raw material components and weight ratios are as follows: 21 parts of styrene-acrylonitrile-maleic anhydride copolymer and 4 parts of silicon carbide fiber.

[0085] The preparation of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is described in Example 1.

[0086] A polyvinyl chloride composite material, the raw material components and weight proportions of which are as follows: 100 parts polyvinyl chloride, the styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared above, 2 parts calcium-zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0087] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0088] Comparative Example 4: Preparation of a Polyvinyl Chloride Composite Material

[0089] The difference from Example 1 is that, instead of preparing a styrene-acrylonitrile-maleic anhydride copolymer masterbatch, spherical graphite powder and silicon carbide fiber are directly mixed with other raw materials to prepare polyvinyl chloride composite material.

[0090] A high thermal stability polyvinyl chloride composite material, the raw material components and weight proportions are as follows: 100 parts polyvinyl chloride, 1 part spherical graphite powder, 4 parts silicon carbide fiber, 2 parts calcium zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0091] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0092] Comparative Example 5: Preparation of a styrene-acrylonitrile-maleic anhydride copolymer masterbatch and a polyvinyl chloride composite material

[0093] The difference from Example 1 is that spherical graphite powder, silicon carbide fiber, and styrene-acrylonitrile-maleic anhydride copolymer are directly mixed with other raw materials to obtain a mixed powder, without first preparing a styrene-acrylonitrile-maleic anhydride copolymer masterbatch, and are added directly.

[0094] A polyvinyl chloride composite material, the raw material components and weight proportions of which are as follows: 100 parts polyvinyl chloride, 20 parts styrene-acrylonitrile-maleic anhydride copolymer, 1 part spherical graphite powder, 4 parts silicon carbide fiber, 2 parts calcium zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide and 1.5 parts stearic acid.

[0095] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0096] Comparative Example 6: Preparation of a styrene-acrylonitrile-maleic anhydride copolymer masterbatch and a polyvinyl chloride composite material

[0097] The difference from Example 1 is that the nano-graphite powder in the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is replaced with an equal amount of graphite sheets.

[0098] A styrene-acrylonitrile-maleic anhydride copolymer masterbatch has the following raw material components and weight ratios: 20 parts styrene-acrylonitrile-maleic anhydride copolymer, 1 part graphite sheet and 4 parts silicon carbide fiber.

[0099] The preparation of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is described in Example 1.

[0100] A polyvinyl chloride composite material, the raw material components and weight proportions of which are as follows: 100 parts polyvinyl chloride, the styrene-acrylonitrile-maleic anhydride copolymer masterbatch prepared above, 2 parts calcium-zinc heat stabilizer, 10 parts magnesium hydroxide, 15 parts calcium carbonate, 2 parts titanium dioxide, and 1.5 parts stearic acid.

[0101] The preparation of the polyvinyl chloride composite material is described in Example 1.

[0102] Test Example 1: Determination of Heat Resistance and Thermal Stability Data

[0103] Table 1 Measurement Results

[0104]

[0105] As shown in Table 1, Examples 1-4 of this invention yielded polyvinyl chloride (PVC) composite materials with excellent heat resistance and thermal stability, exhibiting a static thermal stability time > 40 min and a Vicat softening point > 93 °C. Furthermore, with the increase in the content of spherical graphite powder, silicon carbide fiber, and calcium-zinc heat stabilizer, the heat resistance and thermal stability of the resulting PVC composite materials were further improved. This indicates that the styrene-acrylonitrile-maleic anhydride copolymer masterbatch obtained by melt mixing styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder, and silicon carbide fiber can effectively improve the heat resistance and thermal stability of PVC.

[0106] As shown in Comparative Examples 1-4, the absence of spherical graphite powder, carbon fiber, or one or more of the styrene-acrylonitrile-maleic anhydride copolymer in the styrene-acrylonitrile-maleic anhydride copolymer masterbatch improves the heat resistance of the resulting polyvinyl chloride composite material, but the improvement effect is not significant.

[0107] As shown in Comparative Example 5, when spherical graphite powder is not pre-prepared into a styrene-acrylonitrile-maleic anhydride copolymer masterbatch by mixing spherical graphite powder with carbon fiber and other raw materials to directly prepare polyvinyl chloride composite material, the improvement effect is still not good.

[0108] As shown in Comparative Example 6, when the nano-graphite powder in the styrene-acrylonitrile-maleic anhydride copolymer masterbatch is replaced with graphite flakes, the crystallinity of the graphite flakes is relatively low compared to spherical graphite, and the improvement effect on the resulting composite material is still poor.

[0109] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A styrene-acrylonitrile-maleic anhydride copolymer masterbatch, characterized in that, It is prepared from styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder and silicon carbide fiber; The mass ratio of the styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder, and silicon carbide fiber is 1:(0.025~0.75):(0.075~1.25).

2. The styrene-acrylonitrile-maleic anhydride copolymer masterbatch according to claim 1, characterized in that, The mass ratio of the styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder, and silicon carbide fiber is 1:(0.1~0.75):(0.1~1.25).

3. The styrene-acrylonitrile-maleic anhydride copolymer masterbatch according to claim 1, characterized in that, The styrene-acrylonitrile-maleic anhydride copolymer contains 25-35 wt% styrene, 60-70 wt% acrylonitrile, and 3-8 wt% maleic anhydride by mass, respectively.

4. The styrene-acrylonitrile-maleic anhydride copolymer masterbatch according to claim 1, characterized in that, The spherical graphite powder has a particle size of 20~60 μm.

5. The styrene-acrylonitrile-maleic anhydride copolymer masterbatch according to claim 1, characterized in that, The aspect ratio of the silicon carbide fiber is 100~200:

1.

6. A method for preparing the styrene-acrylonitrile-maleic anhydride copolymer masterbatch according to any one of claims 1 to 5, characterized in that, The process includes the following steps: drying styrene-acrylonitrile-maleic anhydride copolymer, spherical graphite powder, and silicon carbide fiber, mixing them thoroughly, melting and blending them at 190~210 ℃, and cooling them to obtain styrene-acrylonitrile-maleic anhydride copolymer masterbatch.

7. The use of the styrene-acrylonitrile-maleic anhydride copolymer masterbatch according to any one of claims 1 to 5 in modified polyvinyl chloride.

8. A polyvinyl chloride composite material, characterized in that, It is mainly made of the following raw materials in parts by weight: 100 parts of polyvinyl chloride, 24-65 parts of styrene-acrylonitrile-maleic anhydride copolymer masterbatch as described in any one of claims 1 to 5, 1-10 parts of calcium-zinc heat stabilizer, 5-20 parts of magnesium hydroxide, 5-20 parts of calcium carbonate, 1-10 parts of titanium dioxide and 1-10 parts of stearic acid.

9. The method for preparing the polyvinyl chloride composite material according to claim 8, characterized in that, The process includes the following steps: thoroughly mixing the raw materials, melting and blending them at 165~190 ℃, cutting and molding them, and cooling them to obtain polyvinyl chloride composite materials.

10. The preparation method according to claim 9, characterized in that, The molding temperature is 180~190 ℃.

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