Bio-based biodegradable heat-resistant injection molding resin and preparation method thereof

Abstract

The present invention provides a bio-based biodegradable heat-resistant injection molding resin and a preparation method thereof, and relates to the field of high polymer materials, the bio-based biodegradable heat-resistant injection molding resin is obtained by extrusion granulation of a blending composition of polylactic acid, quartz powder, barium sulfate, a reinforcing agent, talc powder, titanium dioxide, stearic acid, erucyl amide, ethylene bisstearamide, a nucleating agent, polycarbodiimide and white oil. By adding the low-cost inorganic powder (quartz powder, barium sulfate, silicon whisker, talcum powder and titanium dioxide), the cost of the injection molding resin is obviously lower than that of pure polylactic acid; meanwhile, by virtue of the synergistic matching of various specific inorganic powder mixtures and a mixture of the reinforcing agent and the nucleating agent and corresponding proportions, the technical problem that the addition of the inorganic powder has negative effects on the performance of the resin is solved, and the obtained injection molding resin has much higher impact strength and thermal deformation temperature than pure polylactic acid.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high polymer material modification, in particular to a bio-based biodegradable heat-resistant injection molding resin and a preparation method thereof. BACKGROUND

[0002] Biodegradable injection molding resins are mainly polylactic acid (PLA) and polybutylene succinate (PBS). PLA is derived from bio-based starch, starch is fermented to obtain lactic acid, and lactic acid is polymerized to obtain polylactic acid. Therefore, polylactic acid is a bio-based material. The glass transition temperature (Tg) of PLA without blending modification is 60℃. Due to low crystallinity, PLA will deform when the temperature reaches the vicinity of the glass transition temperature, thus showing poor heat resistance. This makes polylactic acid unable to be used to make products used at high temperatures, such as food containers, household appliances, electronic products, automobile parts, etc., and it is difficult to meet the requirement of heat distortion temperature of 100℃ required by daily life catering packaging. The injection molding products required by daily life mainly include cups, plates, knives, forks, spoons, and imitation porcelain tableware, which need to have good impact strength. Polylactic acid is a brittle plastic, and the impact strength is only 3KJ / m 2 Although the method of using toughening agent to toughen can significantly improve the impact strength, it easily leads to a decrease in heat distortion temperature. Increasing the content of inorganic powder can improve the heat distortion temperature and reduce the cost, but it leads to a significant decrease in the impact strength of polylactic acid. How to improve the impact strength of polylactic acid and the heat distortion temperature, and have the advantage of low cost is a difficult problem in the field of biodegradable injection molding products. Therefore, it is of important practical significance to improve the heat resistance of PLA.

[0003] Petchwattana et al. (Polymer Bulletin, 2014, 71(8): 1947-1959) used talc powder to promote the crystallization of PLA, using 1, 5 and 30 μm talc particles as nucleating agents, each with an addition amount of 0-10% to PLA. The study found that the smaller the size of the talc particles, the higher the crystallinity of PLA. With the increase of the addition amount of talc particles, the heat resistance and toughness of modified PLA are increased. Liu Li's master's thesis (Study on Structure and Properties of Attapulgite Modified PLA [D]. Lanzhou: Lanzhou Jiaotong University, 2016) used a melt blending method to prepare PLA / attapulgite nanocomposites, and the thermal stability of PLA was improved. Wang et al. (Materials & Design, 2015, 66(5): 7-15) melt blended amide nucleating agent (TMC-328) with PLA to prepare PLA / TMC composite materials, studied the effect of different TMC content on the Vicat softening temperature (VST), crystallization behavior and heat resistance of PLA, and the heat resistance mechanism of PLA. The results showed that the heat resistance temperature was positively correlated with the crystallinity, crystallization rate constant and cold crystallization rate constant. In addition, the arrangement and movement of molecular chains can affect the heat resistance of PLA. When the addition amount of TMC is 0.2%, the VST reaches 134℃, which is 2.1 times that of pure PLA (64.7℃). Therefore, the addition of nucleating agent TMC improves the crystallinity of PLA, thereby improving the heat resistance of PLA. Zhang et al. (ACS Macro Lett., 2021, 10(1), 154-160) added D-sorbitol as a nucleating agent to PLLA by melt blending. D-sorbitol as a nucleating agent provides nucleation sites for PLLA, making PLLA crystallize faster and more perfectly. PLLA and PDLA can form stereocomplex crystals (SC) by blending. The melting point of SC can reach 230℃, which is higher than that of PLLA and PDLA. SC can also act as a nucleation site for PLLA, further improving the crystallization rate and crystallinity, thereby improving the heat resistance of the product. However, PDLA is very expensive, and the cost of the heat-resistant resin obtained is high, making it difficult to promote and apply. Kuang T et al. (Advanced Composites and Hybrid Materials, 2022, 5(2): 948-959) added 0.5% nucleating agent TMC-306 to PLA to prepare high-performance composites. TMC-306 induces the formation of disordered oriented smectic structure in PLA, and then realizes the chain-like interlocking crystal structure through semi-solid high-pressure molding. The Vicat softening temperature (VST) of the PLA composite material is 112.4℃, which is significantly higher than that of pure PLA.Lv C et al. (International Journal of Biological Macromolecules, 2023, 253: 127265.) prepared a novel PLA composite material using wood fibers and the self-assembling nucleating agent TMC-300 through melt blending and injection molding. TMC-300 can self-assemble into dendritic structures on the surface of wood fibers under hydrogen bonding, thereby inducing epitaxial crystallization of PLA and enhancing the adhesion between the PLA matrix and wood fibers. Niu D et al. (International Journal of Biological Macromolecules, 2023, 234: 123584.) used the bundled diamide organic compound HBNA as a nucleating agent. At high temperature, HBNA was dissolved into the PLA matrix, and then at low temperature, it self-assembled into bundled microcrystals through intermolecular hydrogen bonding, thereby inducing the rapid formation of spherulites and cascades in PLA. Sabzi M et al. (Journal of Applied Polymer Science, 2013, 129(4):1734-1744.) prepared polylactic acid / sepiolite (SEP) composites using a Banbury mixer. The higher the aspect ratio and surface area of ​​the SEP, the higher the melt viscosity, the stronger the shear thinning, and the better the heat resistance of the SEP composite. Arul K (Journal of Thermal Analysis and Calorimetry, 2020, 141(2): 717-725.) prepared a composite material by melt blending basalt (BF) / CQ hybrid fibers to improve the heat resistance of polylactic acid. Cheng H et al. (Journal of Applied Polymer Science, 2024: e56280.) prepared a PLLA / BF / PDLA composite material by melt blending PLLA, basalt fiber (BF), and polydextrose (PDLA). The synergistic effect of BFs and stereocomposite polylactic acid crystals significantly enhances the mechanical, thermomechanical, and heat resistance properties of PLLA. When the mass fraction of PDLA is 10%, the VST of the PLLA / BF / PDLA composite reaches as high as 155.5℃, further expanding the application possibilities of polylactic acid in industrial fields.

[0004] In the prior art, invention patent application number 2025114821204, entitled "A Composite Filler and Its Application in the Preparation of Polylactic Acid Composite Materials," discloses a composite filler and its application in the preparation of polylactic acid composite materials. The composite filler comprises silane-modified inorganic filler particles and zinc phenylphosphonate particles, wherein the inorganic filler is talc or silica; the mass ratio of zinc phenylphosphonate to the inorganic filler ranges from 1 to 5:1. This invention patent's composite filler, used as a nucleating agent in the preparation of polylactic acid composite materials, can effectively control the crystallization properties of polylactic acid, achieving a good balance between the toughness and heat resistance of the polylactic acid composite material, thus giving the polylactic acid composite material excellent toughness and heat resistance.

[0005] However, the bio-based biodegradable heat-resistant injection molding materials prepared by the above-mentioned existing technologies cannot meet the requirements of simultaneously having high heat distortion temperature, high impact strength and low cost.

[0006] Therefore, developing a low-cost bio-based biodegradable injection molding resin material that can simultaneously possess excellent heat distortion temperature, high impact strength, and high filler inorganic powder is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, this application provides a bio-based biodegradable injection molding resin and its preparation method, which has the characteristics of excellent heat distortion temperature, high impact strength and low cost, and has a wide range of applications.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: On one hand, the present invention provides a bio-based biodegradable heat-resistant injection molding resin, characterized in that it is obtained by extrusion granulation of a blend of polylactic acid, quartz powder, barium sulfate, reinforcing agent, talc, titanium dioxide, stearic acid, erucamide, ethylene bis-stearamide, nucleating agent, polycarbodiimide, and white oil. The composition of the heat-resistant injection molding resin comprises, by weight, 50 to 75 parts polylactic acid, 5 to 23 parts quartz powder, 2 to 15 parts barium sulfate, 2 to 15 parts reinforcing agent, 3 to 5 parts talc, 2 parts titanium dioxide, and a lubricant. The lubricant is a blend of stearic acid, erucamide, ethylene bis-stearamide, nucleating agent, polycarbodiimide, and white oil, preferably a blend of 0.1 to 2 parts stearic acid, 0.1 to 2 parts erucamide, 0.1 to 2 parts ethylene bis-stearamide, 0.1 to 2 parts nucleating agent, 0.1 to 2 parts polycarbodiimide, and 0.1 to 2 parts white oil.

[0009] The blend of stearic acid, erucamide, ethylene bis-stearamide, and white oil is used as a lubricant.

[0010] The bio-based polymer selected in this application is polylactic acid (PLA). PLA is a semi-crystalline plastic with severe brittleness and a low heat distortion temperature. It needs to be blended and modified to improve its heat distortion temperature and impact strength.

[0011] In some specific implementations, the polylactic acid has a weight-average molecular weight of 1.5 × 10⁻⁶. 5 g / mol to 3×10 5 g / mol.

[0012] In some specific implementations, the reinforcing agent is silicon whisker.

[0013] In some specific implementations, the nucleating agent is selected as Lak-301 type nucleating agent.

[0014] The blend of stearic acid, erucamide, ethylene bis-stearamide, and white oil is used as a lubricant.

[0015] During injection molding, the injection resin needs to have a suitable melt index. A melt index that is too low makes it difficult to fill the mold, while a melt index that is too high causes the melt to overflow, resulting in flash, increasing post-processing difficulty and wasting material. Lak-301 is a highly efficient nucleating agent for polylactic acid (PLA), significantly improving its crystallinity and crystallization rate, greatly shortening crystallization time, and increasing its heat distortion temperature. It also increases the nucleus density, reduces the size of spherulites, avoids crystal defects caused by collisions between large spherulites, and improves the impact strength of PLA. Polycarbodiimide is a highly efficient anti-hydrolysis agent with reactive cross-linking properties, increasing the cross-linking degree of the PLA matrix, thus improving both heat resistance and hydrolysis resistance. In blends of quartz powder, barium sulfate, whiskering silicon, talc, and titanium dioxide, whiskering silicon, with its fibrous structure, acts as a reinforcing fiber in the polylactic acid (PLA) matrix, improving the impact strength and heat distortion temperature of the injection molding resin. Talc, with its lamellar structure, forms intercalation structures in the PLA matrix, enhancing the heat resistance and processing flow properties of the PLA injection molding resin. Quartz powder acts as an inorganic nucleating agent and reinforcing agent, increasing the crystallinity of PLA and thus raising the heat distortion temperature of the injection molding resin. Barium sulfate improves the transparency of the injection molding resin, while titanium dioxide enhances both crystallinity and whiteness, giving the injection-molded products a porcelain-white and exquisite appearance. A mixture of stearic acid, erucamide, ethylene bis-stearamide, and white oil can regulate the processing fluidity of injection molding resin. Stearic acid can improve the interfacial compatibility between inorganic powder and polylactic acid matrix, while white oil can improve the uniform dispersion of inorganic powder, meeting the high flow performance requirements of injection molding and producing injection molded products with smooth, flawless, and crystal-free surfaces. This formula can solve the heat resistance problem of polylactic acid, improve toughness, and has the advantage of low cost. The technology is advanced and innovative.

[0016] On the other hand, the present invention also provides a method for preparing a bio-based biodegradable injection molding resin, comprising the following steps: The composition of polylactic acid, quartz powder, barium sulfate, reinforcing agent, talc, titanium dioxide, stearic acid, erucamide, ethylene bis-stearamide, nucleating agent, polycarbodiimide, and white oil is mixed evenly in a mixer and then extruded and granulated to obtain injection molding resin.

[0017] In some specific implementations, the extrusion granulation temperature is 160°C. o C to 195 o C. Specifically, in the extrusion granulation process, the extruder's zone 1 temperature is 160℃, zone 2 temperature is 180℃, zone 3 temperature is 190℃, zone 4 temperature is 190℃, zone 5 temperature is 195℃, zone 6 temperature is 195℃, zone 7 temperature is 195℃, zone 8 temperature is 195℃, and zone 9 temperature is 195℃. o C, the temperature in zone 10 is 195. o C, the temperature in zone 11 is 195. o C, the temperature in zone 12 is 190°C. o C, the die head temperature is 185℃. The extruder speed in the extrusion granulation process is 100 rpm to 300 rpm.

[0018] The beneficial effects of this invention are as follows: By adding low-cost inorganic powders (quartz powder, barium sulfate, whisker silicon, talc powder, titanium dioxide), the cost of injection molding resin is significantly lower than that of pure polylactic acid (PLA). Simultaneously, through the synergistic combination of various specific inorganic powder mixtures, as well as mixtures of reinforcing agents and nucleating agents in appropriate proportions, the technical challenge of the negative impact of inorganic powder addition on resin performance is overcome. The resulting injection molding resin exhibits significantly higher impact strength and heat distortion temperature than pure PLA. It is suitable for use in melamine tableware, cutlery, spoons, and other products, as well as heat-resistant coffee capsules, pen tubes, golf miters, toys, and stationery; thus expanding the application scope of bio-based PLA materials and contributing to environmental protection. Detailed Implementation

[0019] This application provides a heat-resistant injection molding resin, which is obtained by extrusion granulation of a blend of polylactic acid, quartz powder, barium sulfate, whisker silica, talc, titanium dioxide, stearic acid, erucamide, ethylene bis-stearamide, nucleating agent Lak-301, polycarbodiimide, and white oil. The composition of the heat-resistant injection molding resin comprises, by weight, 50 to 75 parts of polylactic acid, 5 to 30 parts of quartz powder, 2 to 15 parts of barium sulfate, 1 to 15 parts of whisker silica, 1 to 10 parts of talc, 1 to 5 parts of titanium dioxide, 0.1 to 2 parts of stearic acid, 0.1 to 2 parts of erucamide, 0.1 to 2 parts of ethylene bis-stearamide, 0.1 to 2 parts of nucleating agent Lak-301, 0.1 to 2 parts of polycarbodiimide, and 0.1 to 2 parts of white oil.

[0020] Weigh out all the above components according to the specified proportions, mix them thoroughly in a mixer, and then add them to a twin-screw extruder. Set the extruder temperature as follows: Zone 1: 160℃; Zone 2: 180℃; Zone 3: 190℃; Zone 4: 190℃; Zone 5: 195℃; Zone 6: 195℃; Zone 7: 195℃; Zone 8: 195℃; Zone 9: 195℃. o C, the temperature in zone 10 is 195. o C, the temperature in zone 11 is 195. o C, the temperature in zone 12 is 190°C. o C, the die head temperature is 185℃. In the extrusion granulation process, the extruder speed is 100 rpm to 300 rpm, and the extruded, air-cooled, drawn, and pelletized resin is obtained for injection molding.

[0021] The present application is further illustrated below with reference to the embodiments. The scope of protection of the present application is not limited by the following embodiments.

[0022] In the following examples, polylactic acid (PLA) was purchased from Zhejiang Hisun Biomaterials Co., Ltd., model REVODE290; quartz powder was purchased from Lianyungang Miaojing Silicon Materials Co., Ltd.; barium sulfate from Langfang Shuangma Chemical Co., Ltd.; whisker silicon from Shijiazhuang Chaowei New Materials Technology Co., Ltd.; talc powder from Liaoning Jinghua New Materials Co., Ltd.; titanium dioxide from Shanghai Yanju Industrial Co., Ltd.; stearic acid from Jingxian Longyuan Chemical Co., Ltd.; erucamide from Jiangxi Weike Oil & Chemical Co., Ltd.; ethylene bis-stearamide from Sichuan Tianyu Oil & Chemical Co., Ltd.; nucleating agent Lak-301 from Dongguan Weicai Plastic Raw Materials Co., Ltd.; polycarbodiimide from Shanghai Lai'an Industrial Co., Ltd.; and white oil from Maoming Hongtai Petrochemical Co., Ltd.

[0023] The extruder is an AK-36 twin-screw extruder from Nanjing Keya Chemical Complete Equipment Co., Ltd.

[0024] Example 1 This embodiment provides a bio-based biodegradable injection molding resin and its preparation method. The injection molding resin is obtained by extrusion granulation of a blend of polylactic acid, quartz powder, barium sulfate, whisker silicon, talc, titanium dioxide, stearic acid, erucamide, ethylene bis-stearamide, nucleating agent Lak-301, polycarbodiimide, and white oil.

[0025] The composition of the heat-resistant injection molding resin comprises, by weight, 50 parts polylactic acid, 23 parts quartz powder, 5 parts barium sulfate, 10 parts whisker silicon, 5 parts talc, 2 parts titanium dioxide, 1 part stearic acid, 1 part erucamide, 1 part ethylene bis-stearamide, 0.5 parts nucleating agent Lak-301, 0.5 parts polycarbodiimide, and 1 part white oil.

[0026] Weigh out all the above components according to the specified proportions, mix them thoroughly in a mixer, and then add them to a twin-screw extruder. Set the extruder temperature as follows: Zone 1: 160℃; Zone 2: 180℃; Zone 3: 190℃; Zone 4: 190℃; Zone 5: 195℃; Zone 6: 195℃; Zone 7: 195℃; Zone 8: 195℃; Zone 9: 195℃. o C, the temperature in zone 10 is 195. o C, the temperature in zone 11 is 195. o C, the temperature in zone 12 is 190°C. o C, the die head temperature is 185℃. In the extrusion granulation process, the extruder speed is 100 rpm to 300 rpm, and the extruded, air-cooled, drawn, and pelletized resin is obtained for injection molding.

[0027] Example 2 This embodiment provides a bio-based biodegradable injection molding resin and its preparation method. The only difference from Example 1 is that the mass fraction of polylactic acid is 60 parts and the mass fraction of quartz powder is 13 parts.

[0028] Example 3 This embodiment provides a bio-based biodegradable injection molding resin and its preparation method. The only difference from Embodiment 1 is that the mass fractions of polylactic acid are 60 parts, the mass fractions of quartz powder are 8 parts, and the mass fractions of whisker silicon are 15 parts.

[0029] Example 4 This embodiment provides a bio-based biodegradable injection molding resin and its preparation method. The only difference from Embodiment 1 is that the mass fractions of polylactic acid are 75 parts, the mass fractions of quartz powder are 5 parts, and the mass fractions of whisker silicon are 3 parts.

[0030] Example 5 This embodiment provides a bio-based biodegradable injection molding resin and its preparation method. The only difference from Embodiment 1 is that the mass fractions of polylactic acid are 60 parts, the mass fractions of quartz powder are 13 parts, the mass fractions of barium sulfate are 15 parts, the mass fractions of whisker silicon are 2 parts, and the mass fractions of talc are 3 parts.

[0031] Example 6 This embodiment provides a bio-based biodegradable injection molding resin and its preparation method. The only difference from Embodiment 1 is that the mass fractions of polylactic acid are 60 parts, the mass fractions of quartz powder are 13 parts, the mass fractions of barium sulfate are 2 parts, the mass fractions of whisker silicon are 15 parts, and the mass fractions of talc are 3 parts.

[0032] Comparative Example 1 The method for preparing injection molding resin in this comparative example is basically the same as in Example 1, except that the mass fraction of polylactic acid is 50.5 parts and the nucleating agent Lak-301 is not used.

[0033] Comparative Example 2 The method for preparing injection molding resin in this comparative example is basically the same as in Example 1, except that the mass fraction of polylactic acid is 50.5 parts and the anti-hydrolysis agent polycarbodiimide is not used.

[0034] Comparative Example 3 The method for preparing injection molding resin in this comparative example is basically the same as in Example 1, except that the mass fraction of polylactic acid is 51 parts, and the nucleating agent Lak-301 and the anti-hydrolysis agent polycarbodiimide are not used.

[0035] Comparative Example 4 The method for preparing injection molding resin in this comparative example is basically the same as in Example 1, except that the nucleating agent Lak-301 is replaced with an equal mass of nucleating agent TMC-306.

[0036] Comparative Example 5 The method for preparing injection molding resin in this comparative example is basically the same as in Example 1, except that the nucleating agent Lak-301 is replaced with an equal mass of nucleating agent TMC-328.

[0037] The performance of the injection molding resins prepared in Examples 1-6 and Comparative Examples 1-5 was tested using the following methods: Tensile strength and elongation at break: GB / T 1040.1-2018 Impact strength: GB / T 1043.1-2008 Heat distortion temperature: GB / T 1634.2-2019 Melt mass flow rate: GB / T 3682.1-2018 The test results are shown in Table 1.

[0038] Table 1

[0039] As can be seen from the results of the above embodiments, the bio-based biodegradable injection molding resin provided in this application has high tensile strength, elongation at break, impact strength, and heat distortion temperature, making it suitable for use in food packaging. Comparing Examples 3, 6, and 1, it can be found that whisker silicon can significantly improve the heat distortion temperature of the injection molding resin. Comparing Example 1 and Comparative Example 1, it can be found that the nucleating agent Lak-301 can significantly improve the tensile strength, elongation at break, impact strength, and heat distortion temperature of the injection molding resin in this system. Comparing Example 1 and Comparative Example 2, it can be found that the anti-hydrolysis agent polycarbodiimide can also improve the tensile strength, elongation at break, and impact strength of the injection molding resin. Comparing Example 1 and Comparative Example 3, it can be found that without the nucleating agent and anti-hydrolysis agent, the tensile strength, elongation at break, impact strength, and heat distortion temperature of the injection molding resin are significantly reduced. When Comparative Examples 4 and 5 are replaced with other types of nucleating agents, the heat distortion temperature is significantly lower than that of Lak-301, and the tensile strength and elongation at break are also significantly reduced.

[0040] Therefore, the present invention can improve tensile strength and tensile elongation at break, as well as impact strength and heat distortion temperature, through the synergistic effect of nucleating agent Lak-301 and anti-hydrolysis agent polycarbodiimide.

[0041] In summary, the bio-based biodegradable injection molding resin provided in this application improves the heat resistance of polylactic acid while also increasing its impact strength, thereby enabling polylactic acid biodegradable materials to have a wider range of applications and contributing to environmental protection.

[0042] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and application concept of this application, should be included within the scope of protection of this application.

Claims

1. A bio-based, biodegradable, heat-resistant injection molding resin, characterized in that, The mixture is obtained by extrusion granulation of a blend of polylactic acid, quartz powder, barium sulfate, reinforcing agent, talc, titanium dioxide, stearic acid, erucamide, ethylene bis-stearamide, nucleating agent, polycarbodiimide, and white oil. The composition of the heat-resistant injection molding resin comprises, by weight, 50 to 75 parts polylactic acid, 5 to 23 parts quartz powder, 2 to 15 parts barium sulfate, 2 to 15 parts reinforcing agent, 3 to 5 parts talc, 2 parts titanium dioxide, and a lubricant, wherein the lubricant is a blend of stearic acid, erucamide, ethylene bis-stearamide, nucleating agent, polycarbodiimide, and white oil.

2. The bio-based biodegradable heat-resistant injection molding resin according to claim 1, characterized in that, The reinforcing agent is whisker silicon.

3. The bio-based biodegradable heat-resistant injection molding resin according to claim 1, characterized in that, The nucleating agent is Lak-301 type nucleating agent.

4. The bio-based biodegradable heat-resistant injection molding resin according to claim 1, characterized in that, The polylactic acid has a weight-average molecular weight of 1.5 × 10⁻⁶. 5 g / mol to 3×10 5 g / mol.

5. A method for preparing a bio-based biodegradable heat-resistant injection molding resin as described in any one of claims 1-4, characterized in that, Includes the following steps: A composition of polylactic acid, quartz powder, barium sulfate, reinforcing agent, talc, titanium dioxide, stearic acid, erucamide, ethylene bis-stearamide, nucleating agent, polycarbodiimide, and white oil is mixed evenly in a mixer and then extruded and granulated to obtain injection molding resin. The injection molding resin is then processed by an injection molding machine to obtain heat-resistant injection molded products.

6. The preparation method according to claim 5, characterized in that, The extrusion granulation temperature is 160°C to 195°C.

7. The preparation method according to claim 6, characterized in that, In the extrusion granulation process, the temperature of the extruder is 160℃ in zone 1, 180℃ in zone 2, 190℃ in zone 3, 190℃ in zone 4, 195℃ in zone 5, 195℃ in zone 6, 195℃ in zone 7, 195℃ in zone 8, 195℃ in zone 9, 195℃ in zone 10, 195℃ in zone 11, 190℃ in zone 12, and 185℃ at the die head.

8. The preparation method according to claim 6, characterized in that, In the extrusion granulation process, the speed of the extruder is 100 rpm to 300 rpm.

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