A method for recycling waste PC plastics to prepare headlight plastic parts

Abstract

A method for recycling waste PC plastics to prepare headlight plastic parts according to the present invention comprises the following steps: 1) After crushing the waste PC plastics, cleaning and removing impurities, soaking them with an impregnating agent, then continuously cleaning them with a NaOH solution with a mass concentration of 0.01-0.05%, and then rinsing with clean water and drying for standby; 2) Mixing the dried PC material with a lubricant, a coupling agent, and an antioxidant, performing primary granulation after drying treatment, then adding chitosan, hollow spherical micron-sized barium sulfate, and hollow spherical nano-sized barium sulfate and mixing for secondary granulation, and performing injection molding after secondary granulation to obtain a headlight plastic part product. The method for recycling waste PC plastics to prepare headlight plastic parts according to the present invention has a high removal rate of paint and oil stains, and the prepared headlight plastic parts have a low self-weight and excellent mechanical properties, and can better meet the actual needs.

Description

Technical Field

[0001] The invention relates to the technical field of plastic recycling, and in particular to a method for preparing automobile lamp plastic parts by recycling waste PC plastics. Background Art

[0002] PC (polycarbonate) is a commonly used plastic material with the characteristics of high strength, high temperature resistance, good transparency, etc. Therefore, it is widely used in many industries and daily necessities, such as electronic product housings, auto parts, safety glasses, bottles, etc. In addition, PC plastics are also used in the manufacture of bulletproof materials. The extensive and large-scale application has brought about a rapid increase in PC consumption. With the inevitable generation of a large number of discarded PC products, the recycling and reuse of PC products is a hot spot in research and development. The headlight plastic parts are parts such as headlight housings or internal brackets made of plastic. Their main function is to protect the internal components of the headlights and beautify the appearance of the vehicle. The headlight plastic parts made of PC are more common products on the market. In the prior art, there is a technology for recycling PC to prepare headlight plastic parts. However, the removal of impurities and coatings from waste PC is difficult, and the improvement of the mechanical properties of the PC plastic parts obtained after processing is also a research focus. Therefore, the present invention aims to develop a method for recycling waste PC plastics to prepare headlight plastic parts to better meet market needs. Summary of the invention

[0003] The technical problem solved by the present invention is to provide a method for recycling waste PC plastics to prepare automobile lamp plastic parts, so as to solve the problems of incomplete paint removal, high density and poor mechanical strength in the prior art of recycling waste PC plastics to prepare automobile lamp plastic parts.

[0004] The technical problem solved by the present invention is achieved by adopting the following technical solutions:

[0005] A method for recycling waste PC plastics to prepare automotive lamp plastic parts comprises the following steps:

[0006] 1) After the waste PC plastic is crushed, it is cleaned and impurities are removed, and then soaked in a wetting agent. After soaking, it is further cleaned with a NaOH solution with a mass concentration of 0.01-0.05%, and then rinsed with clean water and dried for use;

[0007] 2) Mix the dried PC material with lubricant, coupling agent and antioxidant, perform primary granulation after drying, then add chitosan, hollow spherical micron-sized barium sulfate and hollow spherical nano-sized barium sulfate, mix and perform secondary granulation, and perform injection molding after secondary granulation to obtain a headlight plastic product.

[0008] Furthermore, in step 1), the PC waste is crushed into PC particles with a particle size ranging from 2 to 8 mm.

[0009] Further, in step 1), the PC particles are preliminarily washed in clean water and flotation is carried out to remove the upper-layer impurities, and the sinking PC materials are collected; the sinking PC materials are subjected to secondary flotation with a NaCl solution having a mass concentration of 24-26%, and the floating PC materials are collected after the flotation is completed.

[0010] Further, during the preliminary washing process, a washing aid is added. The washing aid is composed of a non-ionic surfactant and an anionic surfactant. The non-ionic surfactant includes TX-10 and MOA-5, and the anionic surfactant is LAB and FMES. The concentration of TX-10 in the washing water is 1.5-1.8 g / L, the concentration of MOA-5 is 0.2-0.4 g / L, the concentration of LAB is 0.3-0.5 g / L, and the concentration of FMES is 1.6-1.8 g / L.

[0011] Further, the washing temperature is 45-55 °C, and the washing time is 6-10 min.

[0012] Further, in step 1), the infiltration is carried out at room temperature. The infiltrant is composed of benzyl alcohol, citric acid, fatty alcohol polyoxyethylene ether and an appropriate amount of water. In the infiltrant, the mass ratio of benzyl alcohol is 30-50%, the mass ratio of citric acid is 20-30%, and the mass ratio of the fatty alcohol polyoxyethylene ether is 0.1-0.15%.

[0013] Further, in step 2), the weight ratio of each raw material component is: 70-80 parts of PC materials, 8-10 parts of hollow spherical micron-sized barium sulfate, 4-8 parts of hollow spherical nano-sized barium sulfate, 3-5 parts of lubricant, 0.1-0.5 parts of chitosan, 1-2 parts of coupling agent, and 1-2 parts of antioxidant.

[0014] Further, it also includes 3-5 parts of rod-shaped micron-sized barium sulfate. The particle size range of the rod-shaped micron-sized barium sulfate is 1-50 μm, the particle size range of the hollow spherical micron-sized barium sulfate is 100-500 μm, and the particle size of the hollow spherical nano-sized barium sulfate is 50-100 nm.

[0015] Further, the lubricant is one or more of polyethylene wax, calcium stearate, zinc stearate and stearic acid; the antioxidant is antioxidant 1076 and / or antioxidant 168; the coupling agent is a silane coupling agent.

[0016] Further, mix PC materials, lubricants, coupling agents, and antioxidants, perform drying treatment and then conduct primary extrusion granulation. Mix the product obtained from extrusion granulation with chitosan, hollow spherical micron-sized barium sulfate, and hollow spherical nano-sized barium sulfate, and then carry out injection molding treatment to obtain a headlight plastic part product. The injection molding treatment conditions are: injection molding temperature 240 - 265 °C, injection pressure 50 - 60 kg / ㎡, injection speed 50 - 60%, and holding pressure 60 - 70 kg / ㎡.

[0017] Beneficial effects: The method for recycling waste PC plastics to prepare headlight plastic parts according to the present invention can improve the traditional process, ensure the paint removal effect, improve the cleaning efficiency, reduce the safety risks brought by operations, and does not require major changes to the existing production line, which can well meet the actual processing needs. Using the recycled PC materials as the base material, with unique micron-sized and nano-sized hollow spherical barium sulfate as the main auxiliary materials, and adding a small amount of chitosan and other auxiliary materials, the prepared headlight plastic parts have better mechanical properties with little increase in self-weight and can better meet the product requirements. Specific embodiments

[0018] In order to make the technical means, creative features, achieved purposes, and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0019] The method for recycling waste PC plastics to prepare headlight plastic parts according to the present invention includes the following steps:

[0020] 1) After crushing waste PC plastics, clean and remove impurities, soak them with an infiltrant, then continue to clean them with a NaOH solution with a mass concentration of 0.01 - 0.05%, and then rinse with clean water and dry for standby;

[0021] 2) Mix the dried and standby PC materials with lubricants, coupling agents, and antioxidants, perform drying treatment and then conduct primary granulation, and then add chitosan, hollow spherical micron-sized barium sulfate, and hollow spherical nano-sized barium sulfate to mix and conduct secondary granulation. After secondary granulation, carry out injection molding treatment to obtain a headlight plastic part product.

[0022] Further, in step 1), the PC waste is crushed into PC particles with a particle size range of 2 - 8 mm.

[0023] Further, in step 1), place the PC particles in clean water for preliminary cleaning and flotation to remove the upper-layer impurities, and collect the sinking PC materials; conduct secondary flotation on the sinking PC materials with a NaCl solution with a mass concentration of 24 - 26%, and collect the floating PC materials after flotation;

[0024] Further, during the preliminary cleaning process, a cleaning aid is added. The cleaning aid is composed of a compound of a non-ionic surfactant and an anionic surfactant. The non-ionic surfactant includes TX-10 and MOA-5, and the anionic surfactant is LAB and FMES. In the cleaning water, the concentration of TX-10 is 1.5 - 1.8 g / L, the concentration of MOA-5 is 0.2 - 0.4 g / L, the concentration of LAB is 0.3 - 0.5 g / L, and the concentration of FMES is 1.6 - 1.8 g / L. During the preliminary cleaning process, the cleaning aid composed of the compound of the non-ionic surfactant and the anionic surfactant fully cleans the stains and impurities on the surface of the PC particles. After cleaning, the oil stains and the impurities with a relatively light specific gravity mixed in the PC particles float, so as to be fully removed. The water used for preliminary cleaning can be recycled, and it is beneficial to the subsequent full removal of the paint. Moreover, the cleaning aid composed of a specific compound of a non-ionic surfactant and an anionic surfactant combined with a specific treatment temperature has an oil removal rate as high as 99%, high oil removal efficiency, can be recycled, and has a relatively low raw material cost.

[0025] Further, the cleaning temperature is 45 - 55 °C, and the cleaning time is 6 - 10 min.

[0026] Further, in step 1), the infiltration is carried out at room temperature. The infiltrant is composed of benzyl alcohol, citric acid, fatty alcohol polyoxyethylene ether and an appropriate amount of water. In the infiltrant, the mass ratio of benzyl alcohol is 30 - 50%, the mass ratio of citric acid is 20 - 30%, and the mass ratio of the fatty alcohol polyoxyethylene ether is 0.1 - 0.15%. Through the specific infiltration step and the setting of the infiltrant, the paint on the surface of the PC material is penetrated and swollen by the infiltrant to be in a slightly peeled state. In subsequent processing, only a very low concentration of alkali treatment is required to well achieve the peeling and removal of the stubborn paint.

[0027] Further, in step 2), the weight ratio of each raw material component is: 70 - 80 parts of PC material, 8 - 10 parts of hollow spherical micron-sized barium sulfate, 4 - 8 parts of hollow spherical nano-sized barium sulfate, 3 - 5 parts of lubricant, 0.1 - 0.5 parts of chitosan, 1 - 2 parts of coupling agent, and 1 - 2 parts of antioxidant. Using the PC material as the base material, adopting unique micron-sized and nano-sized hollow spherical barium sulfate as the main auxiliary materials, and adding a small amount of chitosan and other auxiliary materials, the prepared headlight plastic part has better mechanical properties without much increase in its own weight. In the technical solution of the present invention, under the combined action of chitosan and the coupling agent, the hollow spherical barium sulfate with different particle sizes is embedded and crosslinked with the PC material base to form a more complex structure, thereby obtaining a product with better mechanical strength.

[0028] Further, it also includes 3 to 5 parts of rod-shaped micron-sized barium sulfate. The particle size range of the rod-shaped micron-sized barium sulfate is 1 to 50 μm, the particle size range of the hollow spherical micron-sized barium sulfate is 100 to 500 μm, and the particle size of the hollow spherical nano-sized barium sulfate is 50 to 100 nm. The hollow spherical barium sulfate with different particle sizes is further combined with the rod-shaped micron-sized barium sulfate, and its structure is further arranged intricately and is more closely connected to each other. Compared with a single structure, it can better resist external pressure, thereby further improving its own mechanical strength. The rod-shaped micron-sized barium sulfate plays a bridging role inside, and if the particle size is too large or too small, the effect will be unsatisfactory.

[0029] Further, the lubricant is one or more of polyethylene wax, calcium stearate, zinc stearate, and stearic acid; the antioxidant is antioxidant 1076 and / or antioxidant 168; the coupling agent is a silane coupling agent.

[0030] Further, the PC material, lubricant, coupling agent, and antioxidant are mixed, and after drying treatment, they are extruded and granulated once. The product obtained by extrusion granulation is mixed with chitosan, hollow spherical micron-sized barium sulfate, and hollow spherical nano-sized barium sulfate, and then injection molding treatment is carried out to obtain a headlight plastic part product. The injection molding treatment conditions are: injection molding temperature 240 - 265 °C, injection pressure 50 - 60 kg / ㎡, injection speed 50 - 60%, and holding pressure 60 - 70 kg / ㎡.

[0031] First, conduct experiments on the cleaning stage of waste PC plastics.

[0032] Example 1

[0033] In this example, the cleaning of waste PC plastics includes the following steps:

[0034] 1) Crush the PC waste into PC particles with a particle size range of 2 - 8 mm;

[0035] 2) Place the PC particles in clean water for preliminary cleaning and flotation to remove the upper-layer impurities. Use immersion cleaning, keep stirring during the cleaning process, the cleaning temperature is 50 °C, the cleaning time is 8 min. After cleaning, let it stand and collect the settled PC material; perform secondary flotation on the settled PC material with a 25% mass concentration of NaCl solution, and collect the floating PC material after flotation;

[0036] 3) Immerse the collected PC material in the wetting agent for 15 min at room temperature; the wetting agent is composed of benzyl alcohol, citric acid, fatty alcohol polyoxyethylene ether, and an appropriate amount of water. In the wetting agent, the mass proportion of benzyl alcohol is 40%, the mass proportion of citric acid is 25%, and the mass proportion of the fatty alcohol polyoxyethylene ether is 0.1%.

[0037] 4) Continuously wash the soaked PC material with a NaOH solution having a mass concentration of 0.02% for 15 min; after the NaOH solution washing is completed, rinse with clean water and then dry.

[0038] Example 2

[0039] In this example, the cleaning of waste PC plastics includes the following steps:

[0040] 1) Crush the PC waste into PC particles with a particle size range of 2 - 8 mm;

[0041] 2) Place the PC particles in clean water for preliminary cleaning and flotation to remove the upper-layer impurities. Use immersion cleaning, keep stirring during the cleaning process, the cleaning temperature is 50 °C, the cleaning time is 8 min. After the cleaning is completed, let it stand and collect the settled PC material; add a cleaning aid during the preliminary cleaning. The cleaning aid is composed of a non-ionic surfactant and an anionic surfactant. Specifically, the concentration of TX-10 in the cleaning water is 1.6 g / L, the concentration of MOA-5 is 0.3 g / L, the concentration of LAB is 0.4 g / L, and the concentration of FMES is 1.7 g / L; perform secondary flotation on the settled PC material with a NaCl solution having a mass concentration of 25%, and collect the floating PC material after the flotation is completed;

[0042] 3) Immerse the collected PC material in an impregnating agent at room temperature for 15 min; the impregnating agent is composed of benzyl alcohol, citric acid, fatty alcohol polyoxyethylene ether and an appropriate amount of water. In the impregnating agent, the mass ratio of benzyl alcohol is 40%, the mass ratio of citric acid is 25%, and the mass ratio of the fatty alcohol polyoxyethylene ether is 0.12%.

[0043] 4) Continuously wash the soaked PC material with a NaOH solution having a mass concentration of 0.02% for 15 min; after the NaOH solution washing is completed, rinse with clean water and then dry.

[0044] Example 3

[0045] In this example, the cleaning of waste PC plastics includes the following steps:

[0046] 1) Crush the PC waste into PC particles with a particle size range of 2 - 8 mm;

[0047] 2) Place the PC particles in clean water for preliminary cleaning and flotation to remove the upper-layer debris. Use immersion cleaning, and keep stirring during the cleaning process. The cleaning temperature is 50 °C, and the cleaning time is 8 min. After cleaning, let it stand and collect the settled PC material. Add a cleaning aid during the preliminary cleaning. The cleaning aid is composed of a non-ionic surfactant and an anionic surfactant. Specifically, the concentration of TX-10 in the cleaning water is 1.6 g / L, the concentration of MOA-5 is 0.3 g / L, the concentration of LAB is 0.4 g / L, and the concentration of FMES is 1.7 g / L. Perform secondary flotation on the settled PC material with a 25% (mass concentration) NaCl solution, and collect the floating PC material after flotation.

[0048] 3) Immerse the collected PC material in an impregnating agent at room temperature for 15 min. The impregnating agent consists of benzyl alcohol, citric acid, fatty alcohol polyoxyethylene ether and an appropriate amount of water. In the impregnating agent, the mass ratio of benzyl alcohol is 40%, the mass ratio of citric acid is 25%, and the mass ratio of the fatty alcohol polyoxyethylene ether is 0.1%.

[0049] 4) Continue to clean the immersed PC material with a 0.02% (mass concentration) NaOH solution. The NaOH solution also contains 0.01% (mass concentration) hydrogen peroxide. The cleaning time is 15 min, and ultrasonic cleaning is used during the cleaning process. The ultrasonic power is 1200 W. After cleaning with the NaOH solution, rinse with clean water and then dry.

[0050] Control Example 1

[0051] The cleaning of waste PC plastics in this control example includes the following steps:

[0052] 1) Crush the PC waste into PC particles with a particle size range of 2 - 8 mm.

[0053] 2) Place the PC particles in clean water for preliminary cleaning and flotation to remove the upper-layer debris, and collect the settled PC material. Perform secondary flotation on the settled PC material with a 25% (mass concentration) NaCl solution, and collect the floating PC material after flotation.

[0054] 3) Continue to clean the collected PC material with a 10% (mass concentration) NaOH solution for 1.5 h. After cleaning, rinse with clean water and dry.

[0055] Control Example 2

[0056] The cleaning of waste PC plastics in this control example includes the following steps:

[0057] 1) Crush the PC waste into PC particles with a particle size range of 2 - 8 mm.

[0058] 2) Place the PC particles in clean water for preliminary cleaning and flotation to remove the upper-layer debris. Use immersion cleaning, and keep stirring during the cleaning process. The cleaning temperature is 50 °C, and the cleaning time is 8 min. After cleaning, let it stand and collect the settled PC materials; Add a cleaning aid during preliminary cleaning. The cleaning aid is a non-ionic surfactant. Specifically, the concentration of TX-10 in the cleaning water is 1.6 g / L, and the concentration of MOA-5 is 0.3 g / L; Perform secondary flotation on the settled PC materials with a 25% NaCl solution by mass concentration, and collect the floating PC materials after flotation;

[0059] 3) Immerse the collected PC materials in an impregnating agent at room temperature for 15 min; The impregnating agent consists of benzyl alcohol, citric acid, fatty alcohol polyoxyethylene ether and an appropriate amount of water. In the impregnating agent, the mass ratio of benzyl alcohol is 50%, the mass ratio of citric acid is 10%, and the mass ratio of the fatty alcohol polyoxyethylene ether is 0.3%.

[0060] 4) Continue to clean the immersed PC materials with a 0.02% NaOH solution by mass concentration. The NaOH solution also contains 0.01% hydrogen peroxide by mass concentration. The cleaning time is 15 min, and ultrasonic cleaning is used during the cleaning process. The ultrasonic power is 1200 W; After cleaning with the NaOH solution, rinse with clean water and then dry.

[0061] Select PC waste materials with stubborn oil stains and paint on the surface of the same batch as raw materials, and count the test results of the products obtained after treatment in each example and control example in terms of oil stain removal rate, paint removal rate and chromaticity. The results are shown in Table 1.

[0062] Continue with the next preparation process using the PC material product obtained in Example 2. Example

[0063] This example includes the following raw materials in parts by weight: 78 parts of PC materials, 10 parts of hollow spherical micron-sized barium sulfate, 5 parts of hollow spherical nano-sized barium sulfate, 4 parts of polyethylene wax, 0.2 parts of chitosan, 1 part of silane coupling agent, and 2 parts of antioxidant 1076. Mix the PC materials, lubricant, coupling agent, and antioxidant evenly, and then dry for 6 h under the condition of 0.05 MPa. After drying, perform primary extrusion granulation. Mix the product obtained by extrusion granulation with chitosan, hollow spherical micron-sized barium sulfate, and hollow spherical nano-sized barium sulfate and then perform injection molding to obtain a headlight plastic part. Among them, the injection molding temperature is 260 °C, the injection pressure is 55 kg / ㎡, the injection speed is 55%, and the holding pressure is 65 kg / ㎡. Example

[0064] This example includes the following raw materials in parts by weight: 78 parts of PC material, 10 parts of hollow spherical micron-sized barium sulfate, 5 parts of hollow spherical nano-sized barium sulfate, 4 parts of rod-shaped micron-sized barium sulfate, 4 parts of polyethylene wax, 0.2 part of chitosan, 1 part of silane coupling agent, and 2 parts of antioxidant 1076. Mix the PC material, lubricant, coupling agent, and antioxidant evenly, then dry for 6 h under the condition of 0.05 MPa, and perform primary extrusion granulation after drying. Mix the product obtained by extrusion granulation with chitosan, hollow spherical micron-sized barium sulfate, hollow spherical nano-sized barium sulfate, and rod-shaped micron-sized barium sulfate, and then perform injection molding to obtain a headlight plastic part. Among them, the injection molding temperature is 260 °C, the injection pressure is 55 kg / ㎡, the injection speed is 55%, and the holding pressure is 65 kg / ㎡. Example

[0065] This example includes the following raw materials in parts by weight: 78 parts of PC material, 10 parts of hollow spherical micron-sized barium sulfate, 5 parts of hollow spherical nano-sized barium sulfate, 4 parts of rod-shaped micron-sized barium sulfate, 4 parts of polyethylene wax, 0.2 part of chitosan, 1 part of silane coupling agent, and 2 parts of antioxidant 1076. Mix the PC material, lubricant, coupling agent, and antioxidant evenly, then dry for 6 h under the condition of 0.05 MPa, and perform primary extrusion granulation after drying. Mix the product obtained by extrusion granulation with chitosan, hollow spherical micron-sized barium sulfate, hollow spherical nano-sized barium sulfate, and rod-shaped micron-sized barium sulfate, and then perform injection molding to obtain a headlight plastic part. Among them, the injection molding temperature is 260 °C, the injection pressure is 55 kg / ㎡, the injection speed is 55%, and the holding pressure is 65 kg / ㎡.

[0066] Comparative Example 3

[0067] This comparative example includes the following raw materials in parts by weight: 78 parts of PC material, 15 parts of hollow spherical nano-sized barium sulfate, 4 parts of polyethylene wax, 0.2 part of chitosan, 1 part of silane coupling agent, and 2 parts of antioxidant 1076. Mix the PC material, lubricant, coupling agent, and antioxidant evenly, then dry for 6 h under the condition of 0.05 MPa, and perform primary extrusion granulation after drying. Mix the product obtained by extrusion granulation with chitosan and hollow spherical nano-sized barium sulfate, and then perform injection molding to obtain a headlight plastic part. Among them, the injection molding temperature is 260 °C, the injection pressure is 55 kg / ㎡, the injection speed is 55%, and the holding pressure is 65 kg / ㎡.

[0068] Comparative Example 4

[0069] This comparative example includes raw materials in the following parts by weight: 78 parts of PC material, 10 parts of hollow spherical micron-sized barium sulfate, 5 parts of hollow spherical nano-sized barium sulfate, 4 parts of polyethylene wax, 1 part of silane coupling agent, and 2 parts of antioxidant 1076. Mix the PC material, lubricant, coupling agent, and antioxidant evenly, then dry for 6 h under the condition of 0.05 MPa, and perform primary extrusion granulation after drying. Mix the product obtained from extrusion granulation with hollow spherical micron-sized barium sulfate and hollow spherical nano-sized barium sulfate, and then perform injection molding to obtain a headlight plastic part. Among them, the injection molding temperature is 260 °C, the injection pressure is 55 kg / ㎡, the injection speed is 55%, and the holding pressure is 65 kg / ㎡.

[0070] Comparative Example 5

[0071] This comparative example includes raw materials in the following parts by weight: 78 parts of PC material, 5 parts of hollow spherical micron-sized barium sulfate, 10 parts of hollow spherical nano-sized barium sulfate, 4 parts of polyethylene wax, 1 part of chitosan, 1 part of silane coupling agent, and 2 parts of antioxidant 1076. Mix the PC material, lubricant, coupling agent, and antioxidant evenly, then dry for 6 h under the condition of 0.05 MPa, and perform primary extrusion granulation after drying. Mix the product obtained from extrusion granulation with chitosan, hollow spherical micron-sized barium sulfate, and hollow spherical nano-sized barium sulfate, and then perform injection molding to obtain a headlight plastic part. Among them, the injection molding temperature is 260 °C, the injection pressure is 55 kg / ㎡, the injection speed is 55%, and the holding pressure is 65 kg / ㎡.

[0072] Comparative Example 6

[0073] This comparative example includes raw materials in the following parts by weight: 78 parts of PC material, 15 parts of hollow spherical nano-sized barium sulfate, 4 parts of polyethylene wax, 1 part of silane coupling agent, and 2 parts of antioxidant 1076. Mix the PC material, lubricant, coupling agent, and antioxidant evenly, then dry for 6 h under the condition of 0.05 MPa, and perform primary extrusion granulation after drying. Mix the product obtained from extrusion granulation with hollow spherical nano-sized barium sulfate, and then perform injection molding to obtain a headlight plastic part. Among them, the injection molding temperature is 260 °C, the injection pressure is 55 kg / ㎡, the injection speed is 55%, and the holding pressure is 65 kg / ㎡.

[0074] Perform performance tests on the products obtained in Examples 4 - 5 and Comparative Examples 3 - 6, and the results are shown in Table 2.

[0075]

[0076] As can be seen from Table 2, when preparing the headlight plastic part with the PC material pretreated by adopting a unique cleaning process as the base material, when using micron-sized and nano-sized hollow spherical barium sulfate as the main auxiliary materials, it is necessary to combine with an appropriate proportion of chitosan to maximize the reduction of its density and improve its mechanical properties at the same time. When adding rod-shaped micron-sized barium sulfate, the mechanical properties can be further improved. It can also be seen from Table 2 that in the technical solution of the present invention, the component ratio is extremely crucial.

[0077] The above shows and describes the basic principle, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A method for recycling waste PC plastics to prepare headlight plastic parts, characterized in that, It includes the following steps: 1) After crushing waste PC plastics, cleaning and removing impurities, soak them with an impregnating agent. The impregnation is carried out at room temperature. The impregnating agent consists of benzyl alcohol, citric acid, fatty alcohol polyoxyethylene ether and appropriate amount of water. In the impregnating agent, the mass ratio of benzyl alcohol is 30 - 50%, the mass ratio of citric acid is 20 - 30%, and the mass ratio of the fatty alcohol polyoxyethylene ether is 0.1 - 0.15%. After soaking, continue to wash with a NaOH solution with a mass concentration of 0.01 - 0.05%, then rinse with clean water and dry for standby; 2) Mix the dried and standby PC materials with a lubricant, a coupling agent, and an antioxidant, perform primary granulation after drying treatment, then add chitosan, hollow spherical micron-sized barium sulfate, and hollow spherical nano-sized barium sulfate, mix them and perform secondary granulation, and then perform injection molding treatment to obtain a headlight plastic part product.

2. The method for recycling waste PC plastics to prepare headlight plastic parts according to claim 1, wherein, In step 1), the PC waste is crushed into PC particles with a particle size range of 2 - 8 mm.

3. The method for recycling waste PC plastics to prepare headlight plastic parts according to claim 2, wherein, In step 1), place the PC particles in clean water for preliminary cleaning and flotation to remove the upper-layer impurities, and collect the sinking PC materials; perform secondary flotation on the sinking PC materials with a NaCl solution with a mass concentration of 24 - 26%, and collect the floating PC materials after the flotation is completed.

4. The method for recycling waste PC plastics to prepare headlight plastic parts according to claim 3, characterized in that, During the preliminary cleaning process, a cleaning aid is added. The cleaning aid is composed of a non-ionic surfactant and an anionic surfactant. The non-ionic surfactant includes TX-10 and MOA-5, and the anionic surfactant is LAB and FMES. The concentration of TX-10 in the cleaning water is 1.5 - 1.8 g / L, the concentration of MOA-5 is 0.2 - 0.4 g / L, the concentration of LAB is 0.3 - 0.5 g / L, and the concentration of FMES is 1.6 - 1.8 g / L.

5. The method for recycling waste PC plastics to prepare headlight plastic parts according to claim 4, characterized in that, The cleaning temperature is 45 - 55 °C, and the cleaning time is 6 - 10 min.

6. The method for recycling waste PC plastics to prepare headlight plastic parts according to claim 1, characterized in that, In step 2), the weight ratio of each raw material component is: 70 - 80 parts of PC materials, 8 - 10 parts of hollow spherical micron-sized barium sulfate, 4 - 8 parts of hollow spherical nano-sized barium sulfate, 3 - 5 parts of lubricant, 0.1 - 0.5 parts of chitosan, 1 - 2 parts of coupling agent, and 1 - 2 parts of antioxidant.

7. The method for recycling waste PC plastics to prepare headlight plastic parts according to claim 6, characterized in that, It also includes 3 - 5 parts of rod-shaped micron-sized barium sulfate. The particle size range of the rod-shaped micron-sized barium sulfate is 1 - 50 um, the particle size range of the hollow spherical micron-sized barium sulfate is 100 - 500 um, and the particle size of the hollow spherical nano-sized barium sulfate is 50 - 100 nm.

8. The method for recycling waste PC plastics to prepare headlight plastic parts according to claim 6, characterized in that, The lubricant is one or more of polyethylene wax, calcium stearate, zinc stearate, and stearic acid; the antioxidant is antioxidant 1076 and / or antioxidant 168; the coupling agent is a silane coupling agent.

9. The method for recycling waste PC plastics to prepare headlight plastic parts according to claim 6, characterized in that, Mix the PC materials, lubricant, coupling agent, and antioxidant, perform primary extrusion granulation after drying treatment, mix the product obtained from the extrusion granulation with chitosan, hollow spherical micron-sized barium sulfate, and hollow spherical nano-sized barium sulfate, and then perform injection molding treatment to obtain a headlight plastic part product. The injection molding treatment conditions are: injection molding temperature 240 - 265 °C, injection pressure 50 - 60 kg / ㎡, injection speed 50 - 60%, and holding pressure 60 - 70 kg / ㎡.

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