Preparation process for preparing low-resistance polymer film by using plastic sintered plate waste

Abstract

A preparation process for preparing a low-resistance polymer film by using plastic sintered plate waste, relating to the technical field of polymer film preparation. The electrical conductivity of a residual material generated during processing of plastic sintered plates is altered by means of methods such as cleaning, crushing, grinding and melt blending, thereby enhancing the efficient utilization of waste materials; this allows for the production of low-resistance polymer films from the residual material generated from the heads and tails of the plastic sintered plates. A three‑stage stretching operation is performed on a semi-finished film blank, and the stretched polymer film exhibits improved mechanical properties, electrical properties, and thermal stability. By optimizing the stretching process, waste of raw materials and energy consumption during processing can be reduced, thereby reducing production costs. The stretching stage operation can reduce internal defects and stress concentration of the films, thereby improving the overall quality and consistency of finished products.

Description

A preparation process for producing low-resistivity polymer membranes using sintered plastic sheet waste

[0001] This application claims priority to Chinese patent application 2024114287034, filed on October 14, 2024. The entire contents of the aforementioned Chinese patent application are incorporated herein by reference. Technical Field

[0002] This invention belongs to the field of polymer membrane preparation technology, and relates to a preparation process for producing low-resistivity polymer membranes using sintered plastic waste. Background Technology

[0003] The waste materials generated from existing filter media are generally disposed of daily along with industrial waste and incinerated by solid waste management units. This method is relatively simple, but its disadvantages are obvious. In addition to consuming energy, it also generates new dust and gas pollution, which is not conducive to green and low-carbon development or the recycling of resources.

[0004] Therefore, how to improve the recycling of waste filter materials, produce low-resistance polymer membranes, and make high-performance materials that turn waste into treasure serve all sectors of the national economy is an important topic that researchers in the filter materials industry attach great importance to, and it is also a problem that urgently needs to be solved in the field of materials today. Summary of the Invention

[0005] The purpose of this invention is to provide a preparation process for producing low-resistance polymer films using sintered plastic waste, which have the characteristics of low resistance and high strength.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A preparation process for producing low-resistivity polymer membranes using waste from sintered plastic sheet processing is disclosed. This process utilizes the leftover materials generated during sintered plastic sheet processing for recycling. These leftover materials consist of two parts: firstly, fine, burr-laden particles screened out during sintered plastic sheet processing; and secondly, materials cut off during product molding. The specific process flow for preparing the low-resistivity polymer membrane is as follows.

[0008] S1: Weigh the raw materials, and by mass percentage, the remaining material is 78-82%, high-density polyethylene is 15-20%, nano silver particles are 1-2%, and carbon nanotubes are 0.5-1%.

[0009] S2: The carbon nanotubes are acid-washed with a 5% hydrochloric acid solution, then washed with deionized water, and drained after washing.

[0010] S3: Mix the drained carbon nanotubes and high-density polyethylene in proportion, with a stirring rate of 550 r / min, a stirring temperature of 95℃, and a stirring time of 1 to 2 h to obtain mixture A;

[0011] S4: Add the remaining material and nano-silver particles in proportion, then add 2-3 wt% paraffin and 0.5-1 wt% catalyst, stir at 950 r / min, stir at 125℃ for 1-2 h, and cool to room temperature after stirring to obtain mixture B.

[0012] S5: Place mixture B into the mold and perform resonance treatment at the same time as placing mixture B. After the treatment is completed, sinter at 235℃ for 2 hours and air cool for 2 hours to obtain a semi-finished film blank.

[0013] S6: The stretching section of the semi-finished film blank is divided into three sections. The first section is length stretching, with the roller section temperature at 125°C and the stretching ratio at 1:6. The second section is correction stretching, with the roller section temperature at ambient temperature and the stretching ratio at 1:1.2. The third section is the forming and finishing section, which performs longitudinal edge trimming and subsequent winding into rolls. After the stretching section operation, the low-resistivity polymer film is obtained.

[0014] Furthermore, the residue is composed of ultra-high molecular weight polyethylene with a molecular weight of 5 million.

[0015] Furthermore, the particle size of the residue in S1 is ≤10μm.

[0016] Furthermore, the particle size of the high-density polyethylene in S1 is ≤15μm.

[0017] Furthermore, the particle size of the silver nanoparticles in S1 is ≤10nm.

[0018] Furthermore, the particle size of the carbon nanotubes in S1 is ≤5nm.

[0019] Furthermore, the catalyst in S4 is one of aluminum oxide, titanium dioxide, and zinc oxide.

[0020] Furthermore, the cooling rate to room temperature in S4 is 3°C / min.

[0021] Furthermore, the parameters for resonance in S5 are: frequency of 500-1000Hz and resonance processing time of 5-10min.

[0022] Furthermore, the air cooling parameters in S5 are: wind speed of 1-2 m / s and wind pressure of 300-500 Pa.

[0023] This invention achieves the recycling of waste plastic sintered steel plate by cleaning, crushing, grinding, sieving, secondary grinding, and re-sieving of the waste material, thereby improving the efficient utilization of waste materials. In this invention, the crusher used is the Jinma 600 type, and the grinding mill used is the BWCJ1000 type.

[0024] Ultra-high molecular weight polyethylene (UHMWPE) has extremely high wear resistance, and its impact strength ranks among the top of all plastics. Moreover, its impact strength increases with the increase of molecular weight. UHMWPE has a low coefficient of friction, good flowability, excellent self-lubricating properties, and exhibits good stability to most chemicals and solvents.

[0025] High-density polyethylene (HDPE) has high tensile strength and yield strength, and can maintain stable properties at high temperatures. HDPE is also a good electrical insulation material and can be easily processed into various products through extrusion, injection molding and other processes.

[0026] Nano-silver particles have extremely high conductivity, which can significantly reduce the resistivity of polymer membranes. Nano-silver also has broad-spectrum antibacterial properties, which helps to improve the hygienic properties of polymer membranes. Furthermore, nano-silver particles can be stably dispersed in polymer matrices and are not prone to agglomeration.

[0027] Carbon nanotubes can significantly improve the mechanical properties of polymer films, and help to further improve the electrical conductivity and heat dissipation properties of polymer films. Carbon nanotubes can maintain stable performance in a variety of chemical environments.

[0028] This invention significantly reduces the resistivity of the polymer membrane and improves its conductivity by adding nano-silver particles. The combination of high-density polyethylene and ultra-high molecular weight polyethylene, along with the addition of carbon nanotubes, significantly enhances the mechanical strength, toughness, and wear resistance of the polymer membrane. During high-temperature sintering, the polymer membrane maintains stable performance and is not easily deformed or degraded. Through a refined preparation process, including stirring, mixing, sintering, and stretching, the polymer membrane can be easily processed into various shapes and sizes. The catalysts and additives used in the preparation process all meet environmental protection requirements and cause no pollution to the environment.

[0029] In this invention, paraffin wax is added as a lubricant, which can reduce friction of raw materials during mixing and processing, making the stirring and mixing process smoother. The addition of paraffin wax can improve the flowability of composite materials, making them easier to process into the required shapes and sizes through processes such as extrusion and injection molding. At the same time, paraffin wax can also improve the demolding properties of composite materials, reduce residues and adhesion in the mold, and in the stretching section, the melting of paraffin wax can provide a certain lubrication and shaping effect, which helps the polymer film maintain a uniform thickness and shape during the stretching process, and reduces stress concentration and cracking during the stretching process.

[0030] By adding 0.5–1 wt% of a catalyst, the interaction and fusion between raw materials such as high-density polyethylene, ultra-high molecular weight polyethylene, silver nanoparticles, and carbon nanotubes can be accelerated, thereby shortening the stirring time and improving production efficiency. The addition of the catalyst can promote the interaction and compatibility between different components, enabling them to be more uniformly dispersed in the matrix and form a stable blend system.

[0031] Through resonance processing, the materials within the mold support each other and become an integrated whole, ensuring sufficient density and full filling of the materials within the mold. This helps the semi-finished product to stretch evenly during the later stretching and film formation process.

[0032] Stretching can rearrange polymer chains in specific directions to form a more ordered structure, thereby improving the physical and electrical properties of the material. Stretching can enhance the strength and toughness of the membrane, making it more resistant to external mechanical stress and impact. During the stretching process, the distribution and arrangement of conductive fillers such as silver nanoparticles and carbon nanotubes in the membrane will change, thereby optimizing the resistivity of the membrane and achieving the desired low resistance effect. Through three-stage stretching, the length, width and thickness of the membrane can be controlled separately, achieving precise forming and cutting to meet the needs of different application scenarios.

[0033] The beneficial effects of this invention are:

[0034] This invention uses methods such as cleaning, crushing, grinding, and blending to change the conductivity of the waste material generated during the processing of sintered plastic plates, thereby improving the efficient utilization of waste materials. This enables the production of low-resistance polymer membranes from the waste materials generated at the beginning and end of the sintered plastic plate processing. Through the combined application of the above processes, the waste materials generated during the processing of sintered plastic filter plates are comprehensively utilized, changing the application properties and conductivity of the materials, improving the efficient recycling of waste materials, and enabling the polymer membrane produced by this process to have low resistance.

[0035] This invention performs a three-stage stretching operation on the semi-finished membrane preform. The stretched polymer membrane exhibits improved mechanical properties, electrical properties, and thermal stability. Furthermore, the three-stage stretching process enables continuous and stable production, improving production efficiency. By optimizing the stretching process, waste of raw materials and energy consumption during processing can be reduced, thereby lowering production costs. The stretching stage operation can also reduce internal defects and stress concentration in the membrane material, improving the overall quality and consistency of the finished product. Attached Figure Description

[0036] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0037] Figure 1. Process route diagram for recycling waste materials from sintered plastic boards;

[0038] Figure 2. Process flow diagram for producing low-resistivity polymer membrane from sintered plastic waste. Detailed Implementation

[0039] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0040] Example 1

[0041] S1: Weigh the raw materials, by mass percentage: 80% remaining material, 18% high-density polyethylene, 1.5% nano-silver particles, and 0.5% carbon nanotubes;

[0042] The residue consists of ultra-high molecular weight polyethylene with a molecular weight of 5 million and a particle size of ≤10μm, high-density polyethylene with a particle size of ≤15μm, silver nanoparticles with a particle size of ≤10nm, and carbon nanotubes with a particle size of ≤5nm.

[0043] S2: The carbon nanotubes are acid-washed with a 5% hydrochloric acid solution, then washed with deionized water, and drained after washing.

[0044] S3: Mix the drained carbon nanotubes and high-density polyethylene in proportion, with a stirring rate of 550 r / min, a stirring temperature of 95℃, and a stirring time of 1 h to obtain mixture A;

[0045] S4: Add the remaining material and nano silver particles in proportion, then add 3wt% paraffin and 1wt% alumina, stir at a speed of 950r / min, stir at a temperature of 125℃ for 2h, and cool to room temperature at a rate of 3℃ / min after stirring to obtain mixture B.

[0046] S5: Place mixture B into the mold and perform resonance treatment at the same time. The parameters of resonance treatment are: frequency of 800Hz, resonance treatment time of 7min, sintering at 235℃ for 2h, air cooling for 2h, air speed of 1.5m / s, air pressure of 400Pa to obtain semi-finished film blank.

[0047] S6: The stretching section of the semi-finished film blank is divided into three sections. The first section is length stretching, with the roller section temperature at 125°C and the stretching ratio at 1:6. The second section is correction stretching, with the roller section temperature at ambient temperature and the stretching ratio at 1:1.2. The third section is the forming and finishing section, which performs longitudinal edge trimming and subsequent winding into rolls. After the stretching section operation, the low-resistivity polymer film is obtained.

[0048] Example 2

[0049] S1: Weigh the raw materials, by mass percentage: 78% remaining material, 20% high-density polyethylene, 1% nano silver particles, and 1% carbon nanotubes;

[0050] The residue consists of ultra-high molecular weight polyethylene with a molecular weight of 5 million and a particle size of ≤10μm, high-density polyethylene with a particle size of ≤15μm, silver nanoparticles with a particle size of ≤10nm, and carbon nanotubes with a particle size of ≤5nm.

[0051] S2: The carbon nanotubes are acid-washed with a 5% hydrochloric acid solution, then washed with deionized water, and drained after washing.

[0052] S3: Mix the drained carbon nanotubes and high-density polyethylene in proportion, with a stirring rate of 550 r / min, a stirring temperature of 95℃, and a stirring time of 2 h to obtain mixture A;

[0053] S4: Add the remaining material and nano silver particles in proportion, then add 2wt% paraffin and 0.5wt% titanium dioxide, stir at a speed of 950r / min, stir at a temperature of 125℃ for 2h, and cool to room temperature at a rate of 3℃ / min after stirring to obtain mixture B.

[0054] S5: Place mixture B into the mold and perform resonance treatment at the same time. The parameters of resonance treatment are: frequency of 500Hz, resonance treatment time of 10min, sintering at 235℃ for 2h, air cooling for 2h, wind speed of 1m / s, and wind pressure of 300Pa to obtain semi-finished film blank.

[0055] S6: The stretching section of the semi-finished film blank is divided into three sections. The first section is length stretching, with the roller section temperature at 125°C and the stretching ratio at 1:6. The second section is correction stretching, with the roller section temperature at ambient temperature and the stretching ratio at 1:1.2. The third section is the forming and finishing section, which performs longitudinal edge trimming and subsequent winding into rolls. After the stretching section operation, the low-resistivity polymer film is obtained.

[0056] Example 3

[0057] S1: Weigh the raw materials. By mass percentage, the remaining material is 82%, high-density polyethylene is 16%, nano silver particles are 1%, and carbon nanotubes are 1%.

[0058] The residue consists of ultra-high molecular weight polyethylene with a molecular weight of 5 million and a particle size of ≤10μm, high-density polyethylene with a particle size of ≤15μm, silver nanoparticles with a particle size of ≤10nm, and carbon nanotubes with a particle size of ≤5nm.

[0059] S2: The carbon nanotubes are acid-washed with a 5% hydrochloric acid solution, then washed with deionized water, and drained after washing.

[0060] S3: Mix the drained carbon nanotubes and high-density polyethylene in proportion, with a stirring rate of 550 r / min, a stirring temperature of 95℃, and a stirring time of 2 h to obtain mixture A;

[0061] S4: Add the remaining material and nano silver particles in proportion, then add 3wt% paraffin and 1wt% zinc oxide, stir at a speed of 950r / min, stir at a temperature of 125℃ for 1h, and cool to room temperature at a rate of 3℃ / min after stirring to obtain mixture B.

[0062] S5: Place mixture B into the mold and perform resonance treatment at the same time. The parameters of resonance treatment are: frequency of 1000Hz, resonance treatment time of 5min, sintering at 235℃ for 2h, air cooling for 2h, wind speed of 2m / s, and wind pressure of 500Pa to obtain semi-finished film blank.

[0063] S6: The stretching section of the semi-finished film blank is divided into three sections. The first section is length stretching, with the roller section temperature at 125°C and the stretching ratio at 1:6. The second section is correction stretching, with the roller section temperature at ambient temperature and the stretching ratio at 1:1.2. The third section is the forming and finishing section, which performs longitudinal edge trimming and subsequent winding into rolls. After the stretching section operation, the low-resistivity polymer film is obtained.

[0064] Comparative Example 1

[0065] In this comparative example, no silver nanoparticles were added during the preparation process, and the remaining steps were the same as in Example 1.

[0066] Comparative Example 2

[0067] In this comparative example, no paraffin was added during the preparation process, and the remaining steps were the same as in Example 1.

[0068] Comparative Example 3

[0069] In this comparative example, no catalyst was added during the preparation process, and the remaining steps were the same as in Example 1.

[0070] Comparative Example 4

[0071] This comparative example does not undergo resonance treatment during preparation; the remaining steps are the same as in Example 1.

[0072] Comparative Example 5

[0073] This comparative example does not perform the second and third stretching operations; the remaining steps are the same as in Example 1.

[0074] The resistance of the films in the examples and comparative examples was tested using a Tektronix™ 385 digital surface resistivity tester; the tensile properties of the films were tested according to GB / T 1040-2006 standard.

[0075] The experimental data are summarized in the table below.

[0076] Experimental data show that the addition of paraffin and catalyst effectively improves the strength of the polymer film, while the addition of silver nanoparticles and the three-stage stretching process effectively reduces the surface resistance of the polymer film.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for preparing a low resistance polymer film using plastic-burned plate waste material, characterized by comprising the steps of: The waste generated during the processing of sintered plastic sheets is recycled and reused. This waste consists of two parts: first, the fine granular material with burrs screened out during the processing of sintered plastic sheets; and second, the material cut off during product molding. The specific process for preparing the low-resistivity polymer film is as follows. ​ S1: Weigh the raw materials, and by mass percentage, the remaining material is 78-82%, high-density polyethylene is 15-20%, nano silver particles are 1-2%, and carbon nanotubes are 0.5-1%. S2: The carbon nanotubes are acid-washed with a 5% hydrochloric acid solution, then washed with deionized water, and drained after washing. S3: Mix the drained carbon nanotubes and high-density polyethylene in proportion, with a stirring rate of 550 r / min, a stirring temperature of 95℃, and a stirring time of 1 to 2 h to obtain mixture A; S4: Add the remaining material and nano-silver particles in proportion, then add 2-3 wt% paraffin and 0.5-1 wt% catalyst, stir at 950 r / min, stir at 125℃ for 1-2 h, and cool to room temperature after stirring to obtain mixture B; S5: Place mixture B into the mold and perform resonance treatment at the same time. After the treatment is completed, sinter at 235℃ for 2 hours and air cool for 2 hours to obtain a semi-finished film blank. S6: The stretching section of the semi-finished film blank is divided into three sections. The first section is length stretching, with the roller section temperature at 125°C and the stretching ratio at 1:

6. The second section is correction stretching, with the roller section temperature at ambient temperature and the stretching ratio at 1:1.

2. The third section is the forming and finishing section, which performs longitudinal edge trimming and subsequent winding into rolls. After the stretching section operation, the low-resistivity polymer film is obtained.

2. The preparation process of low-resistance polymer film using plastic-burned plate waste material according to claim 1, wherein, The residue is composed of ultra-high molecular weight polyethylene with a molecular weight of 5 million.

3. The preparation process of low resistance polymer film using plastic-burned plate waste material according to claim 1, wherein the plastic-burned plate waste material is heated to a temperature of 200-300°C for 1-3 hours. The particle size of the residue in S1 is ≤10μm.

4. The preparation process of low-resistance polymer film using plastic-burned plate waste according to claim 1, wherein the plastic-burned plate waste is a waste of a plastic-burned plate used for a process of manufacturing a printed circuit board. The particle size of the high-density polyethylene in S1 is ≤15μm.

5. The preparation process of low resistance polymer film using plastic-burned plate waste according to claim 1, wherein the waste is heated to 300-400°C for 1-2 hours. The particle size of the silver nanoparticles in S1 is ≤10nm.

6. The preparation process of low resistance polymer film using plastic-burned plate waste according to claim 1, wherein the waste is heated to 300-400°C for 1-2 hours. The carbon nanotubes in S1 have a particle size of ≤5nm.

7. The process for preparing a low-resistance polymer film using plastic-burned plate waste according to claim 1, wherein the plastic-burned plate waste is a waste from a process for manufacturing a plastic-burned plate. The catalyst in S4 is one of aluminum oxide, titanium dioxide, and zinc oxide.

8. The process for preparing a low-resistance polymer film using plastic-burned plate waste according to claim 1, wherein the plastic-burned plate waste is a waste from a process for manufacturing a plastic-burned plate. The cooling rate to room temperature in S4 is 3°C / min.

9. The process for preparing a low-resistance polymer film using plastic-burned plate waste according to claim 1, wherein the plastic-burned plate waste is a waste from a process for manufacturing a plastic-burned plate. The parameters for resonance in S5 are: frequency of 500-1000Hz and resonance processing time of 5-10min.

10. The process for preparing a low-resistance polymer film using plastic-burned plate waste according to claim 1, wherein the plastic-burned plate waste is a waste from a process for manufacturing a plastic-burned plate. The air cooling parameters in S5 are: wind speed of 1-2 m / s and wind pressure of 300-500 Pa.

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