Polytetrafluoroethylene microporous membrane with high interception rate and preparation method thereof

Abstract

The invention belongs to the field of polytetrafluoroethylene microporous membranes, and particularly relates to a polytetrafluoroethylene microporous membrane with a high interception rate and a preparation method thereof. The polytetrafluoroethylene microporous membrane is prepared from the following raw materials in parts by weight: 40 to 50 parts of polytetrafluoroethylene resin powder, 1 to 10 parts of paraffin oil, 1 to 5 parts of alkyl acrylate, 1 to 5 parts of ethylene oxide acrylic resin and 5 to 10 parts of polyalkenyl succinimide. Alkyl acrylate and ethylene oxide acrylic resin can improve wear resistance and corrosion resistance; the high temperature resistance, chemical corrosion resistance and low-temperature flexibility can be improved, the size and distribution of pores are controlled by adjusting the stretching ratio, and the interception rate is improved on the premise that permeability is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of polytetrafluoroethylene microporous membranes, in particular to a polytetrafluoroethylene microporous membrane with a high interception rate and a preparation method thereof. Background Art

[0002] PTFE microporous membrane is a flexible and elastic microporous material with the following characteristics and uses: Features: High porosity and uniform pore size distribution: This makes the membrane have good air permeability and filtration performance. Air permeable and water-tight: The unique microporous structure allows gas to pass through, but liquids cannot penetrate. Stable chemical and thermal properties: It can maintain stable performance over a wide temperature range and is suitable for various harsh environments.

[0003] The patent document with publication (announcement) number: CN111151149B discloses a method for preparing a polytetrafluoroethylene microporous membrane, comprising: S1, mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder and paraffin oil for 0.5-1 hour, and standing at 40-50°C to form a polytetrafluoroethylene blank; S2, pressing and calendering: pressing the polytetrafluoroethylene blank into a cylindrical blank through a pressing machine at 40-50°C; extruding the cylindrical blank into a rod-shaped blank through a push press at 50-60°C material; then the rod-shaped material is calendered into a polytetrafluoroethylene-based tape at 50-80°C by a calender; S3, longitudinal stretching and transverse stretching: the polytetrafluoroethylene-based tape is longitudinally stretched in an oven at 140-150°C, with a stretching ratio of 5-6 times; then the obtained base tape is transversely stretched on a stenter at 140-150°C, with a stretching ratio of 9-10 times; S4, degreasing and heat setting: the film after transverse stretching is degreased and sintered and heat-set to complete the preparation of the polytetrafluoroethylene microporous membrane.

[0004] The polytetrafluoroethylene microporous membrane prepared by the above preparation method has poor performance and low interception rate. Therefore, we propose a polytetrafluoroethylene microporous membrane with a high interception rate and a preparation method thereof to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art that the polytetrafluoroethylene microporous membrane has poor performance and low interception rate, and to propose a polytetrafluoroethylene microporous membrane with a high interception rate and a preparation method thereof.

[0006] The invention provides a polytetrafluoroethylene microporous membrane with a high interception rate, which comprises the following raw materials in parts by weight: 40-50 parts of polytetrafluoroethylene resin powder, 1-10 parts of paraffin oil, 1-5 parts of alkyl acrylate, 1-5 parts of ethylene oxide acrylic resin, and 5-10 parts of polyene succinimide.

[0007] Preferably, the raw materials include the following parts by weight: 40 parts of polytetrafluoroethylene resin powder, 1 part of paraffin oil, 1 part of alkyl acrylate, 1 part of ethylene oxide acrylic resin, and 5 parts of polyalkenyl succinimide.

[0008] Preferably, the raw materials include the following parts by weight: 45 parts of polytetrafluoroethylene resin powder, 5 parts of paraffin oil, 3 parts of alkyl acrylate, 3 parts of ethylene oxide acrylic resin, and 7 parts of polyene succinimide.

[0009] Preferably, the raw materials include the following parts by weight: 50 parts of polytetrafluoroethylene resin powder, 10 parts of paraffin oil, 5 parts of alkyl acrylate, 5 parts of ethylene oxide acrylic resin, and 10 parts of polyalkenyl succinimide.

[0010] The present invention also proposes a method for preparing a polytetrafluoroethylene microporous membrane with a high interception rate, comprising the following steps:

[0011] S1. Mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder, paraffin oil, alkyl acrylate, ethylene oxide acrylic resin, and polyolefin succinimide to form a polytetrafluoroethylene blank;

[0012] S2, blank pressing and calendering: the polytetrafluoroethylene blank is pressed into a cylindrical blank by a blank pressing machine, the cylindrical blank is extruded into a rod-shaped object by a push press, and then the rod-shaped object is calendered into a polytetrafluoroethylene-based tape by a calender at 60° C., so that the base tape has a width of 17-20 cm and a thickness of 500 μm;

[0013] S3, longitudinal stretching and transverse stretching: longitudinally stretch the polytetrafluoroethylene tape in an oven at 260-300°C, with a stretching ratio of 7-9 times, and the obtained base tape has a width of 13-17 cm and a thickness of 300-400 μm; then, transversely stretch the obtained base tape on a stenter at 140-200°C, with a stretching ratio of 14-17 times and a speed of 10 m / min;

[0014] S4, degreasing and heat setting: the transversely stretched film is degreased and sintered at 380°C for heat setting. The sintering time is 2-3 minutes to obtain a heat-set film, thereby completing the preparation of the polytetrafluoroethylene microporous membrane.

[0015] Preferably, the stretching ratio is adjusted as follows: according to the desired performance and application requirements of the polytetrafluoroethylene microporous membrane, a suitable stretching ratio target is set; ensuring that the stretching equipment can accurately control the stretching ratio, and achieving the target stretching ratio by adjusting the parameters of the equipment, such as the stretching speed and temperature; during the stretching process, using a thickness gauge monitoring device to measure the thickness and stretching of the film in real time to ensure that the stretching ratio meets the set requirements; according to the actual situation during the stretching process, continuously optimize the process parameters, such as the stretching temperature and the stretching rate, to obtain a more uniform microporous structure and a higher tensile strength; performing performance tests on the stretched microporous membrane, such as air permeability tests and tensile strength tests, and further verifying and adjusting the stretching ratio according to the test results.

[0016] Preferably, the specific steps of the air permeability test are: placing the microporous membrane in a test device, allowing a constant flow of gas to flow through the material, measuring the time and pressure change required for the gas to pass through the material, and then calculating the air permeability.

[0017] Preferably, the tensile strength test is specifically as follows: prepare a sample from a polytetrafluoroethylene microporous membrane product in accordance with relevant international standards or regulations. The shape and size of the sample must meet the test requirements. It is usually punched out or cut into a standard shape using a mold to ensure that the center of the sample head is symmetrical with the center of the hole to avoid cracks and wave defects affecting the test results. Use a tensile testing machine for testing. The equipment must have high precision and stability to ensure the accuracy of the test results. Before the test, calibrate the tensile testing machine, including setting parameters such as force measurement accuracy and test speed. Measure the length of the sample and record the original length. Clamp the sample on the tensile testing machine to ensure that it is clamped and will not slip. Perform a tensile test according to international standards or prescribed procedures. Usually, the stretching speed is 10-20mm / min or set according to specific requirements. Stretch until the material breaks, record the maximum tension and sample length change at break, and calculate the tensile strength based on the recorded test data.

[0018] Preferably, the thickness gauge is used in the following steps: placing the thickness gauge probe on the surface of the microporous membrane to ensure good contact, starting the thickness gauge, performing real-time thickness measurement, recording and monitoring the measurement data, and ensuring that the film thickness meets the design and standard requirements.

[0019] Preferably, the stretching temperature parameters are adjusted as follows: the microporous membrane is heated using a point-shaped halogen lamp heating element, and the temperature of the heating element is controlled by feedback of a light brightness signal from a sensor, thereby achieving precise adjustment of the stretching temperature.

[0020] Uniform diffusion agent polyene succinimide, which can improve the yield and micropore distribution of microporous membranes; alkyl acrylate: improves wear resistance and corrosion resistance, and is widely used in the fields of automobiles and electronic devices. Ethylene oxide acrylic resin: forms an anti-wear lubricating layer, enhances lubricity and wear resistance, and is suitable for medical devices and chemical equipment.

[0021] The beneficial effects of the present invention are:

[0022] The present invention uses polyolefin succinimide to improve the yield and micropore distribution of the microporous membrane, and alkyl acrylate and ethylene oxide acrylic resin to improve wear resistance and corrosion resistance; high temperature resistance, chemical corrosion resistance and low-temperature flexibility can be improved, and the size and distribution of the pores can be controlled by adjusting the stretching ratio, thereby improving the interception rate while ensuring permeability. DETAILED DESCRIPTION

[0023] The present invention will be further explained below in conjunction with specific embodiments.

[0024] Embodiment 1

[0025] The present invention provides a polytetrafluoroethylene microporous membrane with a high interception rate, comprising the following raw materials in parts by weight: 40 parts of polytetrafluoroethylene resin powder, 1 part of paraffin oil, 1 part of alkyl acrylate, 1 part of ethylene oxide acrylic resin, and 5 parts of polyene succinimide;

[0026] The preparation method comprises the following steps:

[0027] S1. Mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder, paraffin oil, alkyl acrylate, ethylene oxide acrylic resin, and polyolefin succinimide to form a polytetrafluoroethylene blank;

[0028] S2. Blank pressing and calendering: The polytetrafluoroethylene blank is pressed into a cylindrical blank by a blank pressing machine, the cylindrical blank is extruded into a rod-shaped object by a push press, and then the rod-shaped object is calendered into a polytetrafluoroethylene-based tape by a calender at 60° C., so that the base tape has a width of 17 cm and a thickness of 500 μm;

[0029] S3, longitudinal stretching and transverse stretching: longitudinally stretch the polytetrafluoroethylene-based tape in an oven at 260°C with a stretching ratio of 7 times, and the obtained base tape has a width of 13 cm and a thickness of 300 μm; then, the obtained base tape is transversely stretched on a stenter at 140°C with a stretching ratio of 14 times and a speed of 10 m / min. The stretching ratio is adjusted as follows: according to the required performance and application requirements of the polytetrafluoroethylene microporous membrane, set a suitable stretching ratio target; ensure that the stretching equipment can accurately control the stretching ratio, and achieve the target stretching ratio by adjusting the equipment parameters, such as stretching speed and temperature; during the stretching process, use The thickness gauge monitoring equipment measures the thickness and stretching of the film in real time to ensure that the stretching ratio meets the set requirements; according to the actual situation during the stretching process, the process parameters such as stretching temperature and stretching rate are continuously optimized to obtain a more uniform microporous structure and higher tensile strength; the performance tests of the stretched microporous membrane are carried out, such as air permeability test and tensile strength test, and the stretching ratio is further verified and adjusted according to the test results. The specific steps of the air permeability test are: placing the microporous membrane in the test device, allowing a constant flow of gas to flow through the material, measuring the time and pressure change required for the gas to pass through the material, and then calculating the air permeability. The specific steps of the tensile strength test are as follows: Below: Prepare the specimens from the polytetrafluoroethylene microporous membrane products according to the relevant international standards or regulations. The shape and size of the specimens must meet the test requirements. Usually, they are punched out or cut into standard shapes using a mold to ensure that the center of the specimen head is symmetrical with the center of the hole to avoid cracks and wave marks that affect the test results. Use a tensile testing machine for testing. The equipment must have high precision and stability to ensure the accuracy of the test results. Before the test, calibrate the tensile testing machine, including the setting of parameters such as force measurement accuracy and test speed. Measure the length of the specimen and record the original length. Clamp the specimen on the tensile testing machine to ensure that it is clamped tightly and will not slip. According to international standards or regulations, The tensile test is carried out in sequence, the stretching speed is 10mm / min or set according to specific requirements, stretching until the material breaks, recording the maximum tension and sample length change at the time of fracture, and calculating the tensile strength based on the recorded test data. The steps for using the thickness gauge are as follows: place the thickness gauge probe on the surface of the microporous membrane to ensure good contact, start the thickness gauge, perform real-time thickness measurement, record and monitor the measurement data, and ensure that the film thickness meets the design and standard requirements. The stretching temperature parameters are adjusted as follows: use a point-shaped halogen lamp heating element to heat the microporous membrane, and control the temperature of the heating element through the sensor feedback light brightness signal, so as to achieve precise adjustment of the stretching temperature;

[0030] S4, degreasing and heat setting: the transversely stretched membrane is degreased and sintered at 380° C. for 2 minutes to obtain a heat-set film, thereby completing the preparation of the polytetrafluoroethylene microporous membrane.

[0031] Embodiment 2

[0032] The present invention provides a polytetrafluoroethylene microporous membrane with a high interception rate, comprising the following raw materials in parts by weight: 42 parts of polytetrafluoroethylene resin powder, 3 parts of paraffin oil, 2 parts of alkyl acrylate, 2 parts of ethylene oxide acrylic resin, and 6 parts of polyene succinimide;

[0033] The preparation method comprises the following steps:

[0034] S1. Mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder, paraffin oil, alkyl acrylate, ethylene oxide acrylic resin, and polyolefin succinimide to form a polytetrafluoroethylene blank;

[0035] S2, blank pressing and calendering: the polytetrafluoroethylene blank is pressed into a cylindrical blank by a blank pressing machine, the cylindrical blank is extruded into a rod-shaped object by a push press, and then the rod-shaped object is calendered into a polytetrafluoroethylene-based tape by a calender at 60° C., so that the base tape has a width of 18 cm and a thickness of 500 μm;

[0036] S3, longitudinal stretching and transverse stretching: The polytetrafluoroethylene-based tape is longitudinally stretched in an oven at 270°C with a stretching ratio of 7.5 times, and the obtained base tape has a width of 14 cm and a thickness of 320 μm; then the obtained base tape is transversely stretched on a stenter at 150°C with a stretching ratio of 15 times and a speed of 10 m / min. The stretching ratio is adjusted as follows: according to the required performance and application requirements of the polytetrafluoroethylene microporous membrane, a suitable stretching ratio target is set; ensure that the stretching equipment can accurately control the stretching ratio, and achieve the target stretching ratio by adjusting the equipment parameters, such as stretching speed and temperature; during the stretching process, Use a thickness gauge monitoring device to measure the thickness and stretching of the film in real time to ensure that the stretching ratio meets the set requirements; according to the actual situation during the stretching process, continuously optimize the process parameters, such as stretching temperature and stretching rate, to obtain a more uniform microporous structure and higher tensile strength; perform performance tests on the stretched microporous membrane, such as air permeability test and tensile strength test, and further verify and adjust the stretching ratio based on the test results. The specific steps of the air permeability test are: place the microporous membrane in the test device, allow a constant flow of gas to flow through the material, measure the time and pressure change required for the gas to pass through the material, and then calculate the air permeability. The specific steps of the tensile strength test are: place the microporous membrane in the test device, allow a constant flow of gas to flow through the material, measure the time and pressure change required for the gas to pass through the material, and then calculate the air permeability. As follows: Prepare the specimens from the polytetrafluoroethylene microporous membrane products in accordance with relevant international standards or regulations. The shape and size of the specimens must meet the test requirements. Usually, they are punched out or cut into standard shapes using a mold to ensure that the center of the specimen head is symmetrical with the center of the hole to avoid cracks and wave defects affecting the test results. Use a tensile testing machine for testing. The equipment must have high precision and stability to ensure the accuracy of the test results. Before the test, calibrate the tensile testing machine, including the setting of parameters such as force measurement accuracy and test speed. Measure the length of the specimen and record the original length. Clamp the specimen on the tensile testing machine to ensure that it is clamped tightly and will not slip. According to international standards or regulations The program conducts a tensile test, the stretching speed is 12mm / min or set according to specific requirements, stretch until the material breaks, record the maximum tension and sample length change at the time of breakage, and calculate the tensile strength based on the recorded test data. The steps for using the thickness gauge are as follows: place the thickness gauge probe on the surface of the microporous membrane to ensure good contact, start the thickness gauge, perform real-time thickness measurement, record and monitor the measurement data, and ensure that the film thickness meets the design and standard requirements. The stretching temperature parameters are adjusted as follows: use a point-shaped halogen lamp heating element to heat the microporous membrane, and control the temperature of the heating element through the sensor feedback light brightness signal, so as to achieve precise adjustment of the stretching temperature;

[0037] S4, degreasing and heat setting: the transversely stretched membrane is degreased and sintered at 380° C. for 2 minutes to obtain a heat-set film, thereby completing the preparation of the polytetrafluoroethylene microporous membrane.

[0038] Embodiment 3

[0039] The present invention provides a polytetrafluoroethylene microporous membrane with a high interception rate, comprising the following raw materials in parts by weight: 45 parts of polytetrafluoroethylene resin powder, 5 parts of paraffin oil, 3 parts of alkyl acrylate, 3 parts of ethylene oxide acrylic resin, and 7 parts of polyene succinimide;

[0040] The preparation method comprises the following steps:

[0041] S1. Mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder, paraffin oil, alkyl acrylate, ethylene oxide acrylic resin, and polyolefin succinimide to form a polytetrafluoroethylene blank;

[0042] S2. Blank pressing and calendering: The polytetrafluoroethylene blank is pressed into a cylindrical blank by a blank pressing machine, the cylindrical blank is extruded into a rod-shaped object by a push press, and then the rod-shaped object is calendered into a polytetrafluoroethylene-based tape by a calender at 60° C., so that the base tape has a width of 19 cm and a thickness of 500 μm;

[0043] S3, longitudinal stretching and transverse stretching: longitudinally stretch the polytetrafluoroethylene-based tape in an oven at 280°C with a stretching ratio of 8 times, and the obtained base tape has a width of 15 cm and a thickness of 340 μm; then the obtained base tape is transversely stretched on a stenter at 160°C with a stretching ratio of 16 times and a speed of 10 m / min. The stretching ratio is adjusted as follows: according to the required performance and application requirements of the polytetrafluoroethylene microporous membrane, set a suitable stretching ratio target; ensure that the stretching equipment can accurately control the stretching ratio, and achieve the target stretching ratio by adjusting the equipment parameters, such as stretching speed and temperature; during the stretching process, use The thickness gauge monitoring equipment measures the thickness and stretching of the film in real time to ensure that the stretching ratio meets the set requirements; according to the actual situation during the stretching process, the process parameters such as stretching temperature and stretching rate are continuously optimized to obtain a more uniform microporous structure and higher tensile strength; the performance tests of the stretched microporous membrane are carried out, such as air permeability test and tensile strength test, and the stretching ratio is further verified and adjusted according to the test results. The specific steps of the air permeability test are: placing the microporous membrane in the test device, allowing a constant flow of gas to flow through the material, measuring the time and pressure change required for the gas to pass through the material, and then calculating the air permeability. The specific steps of the tensile strength test are as follows: Below: Prepare the specimens from the polytetrafluoroethylene microporous membrane products according to the relevant international standards or regulations. The shape and size of the specimens must meet the test requirements. Usually, they are punched out or cut into standard shapes using a mold to ensure that the center of the specimen head is symmetrical with the center of the hole to avoid cracks and wave marks that affect the test results. Use a tensile testing machine for testing. The equipment must have high precision and stability to ensure the accuracy of the test results. Before the test, calibrate the tensile testing machine, including the setting of parameters such as force measurement accuracy and test speed. Measure the length of the specimen and record the original length. Clamp the specimen on the tensile testing machine to ensure that it is clamped tightly and will not slip. According to international standards or regulations, The tensile test is carried out in sequence, the stretching speed is 13mm / min or set according to specific requirements, stretching until the material breaks, recording the maximum tension and sample length change at the time of breakage, and calculating the tensile strength based on the recorded test data. The steps for using the thickness gauge are as follows: place the thickness gauge probe on the surface of the microporous membrane to ensure good contact, start the thickness gauge, perform real-time thickness measurement, record and monitor the measurement data, and ensure that the film thickness meets the design and standard requirements. The stretching temperature parameters are adjusted as follows: use a point-shaped halogen lamp heating element to heat the microporous membrane, and control the temperature of the heating element through the sensor feedback light brightness signal, so as to achieve precise adjustment of the stretching temperature;

[0044] S4, degreasing and heat setting: the transversely stretched membrane is degreased and sintered at 380° C. for 3 minutes to obtain a heat-set film, thereby completing the preparation of the polytetrafluoroethylene microporous membrane.

[0045] Embodiment 4

[0046] The present invention provides a polytetrafluoroethylene microporous membrane with a high interception rate, comprising the following raw materials in parts by weight: 48 parts of polytetrafluoroethylene resin powder, 8 parts of paraffin oil, 4 parts of alkyl acrylate, 4 parts of ethylene oxide acrylic resin, and 9 parts of polyene succinimide;

[0047] The preparation method comprises the following steps:

[0048] S1. Mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder, paraffin oil, alkyl acrylate, ethylene oxide acrylic resin, and polyolefin succinimide to form a polytetrafluoroethylene blank;

[0049] S2. Blank pressing and calendering: The polytetrafluoroethylene blank is pressed into a cylindrical blank by a blank pressing machine, the cylindrical blank is extruded into a rod-shaped object by a push press, and then the rod-shaped object is calendered into a polytetrafluoroethylene-based tape by a calender at 60° C., so that the base tape has a width of 19 cm and a thickness of 500 μm;

[0050] S3, longitudinal stretching and transverse stretching: The polytetrafluoroethylene-based tape is longitudinally stretched in an oven at 290°C with a stretching ratio of 8.5 times, and the obtained base tape has a width of 16 cm and a thickness of 380 μm; then the obtained base tape is transversely stretched on a stenter at 190°C with a stretching ratio of 16 times and a speed of 10 m / min. The stretching ratio is adjusted as follows: according to the required performance and application requirements of the polytetrafluoroethylene microporous membrane, a suitable stretching ratio target is set; ensure that the stretching equipment can accurately control the stretching ratio, and achieve the target stretching ratio by adjusting the equipment parameters, such as stretching speed and temperature; during the stretching process, Use a thickness gauge monitoring device to measure the thickness and stretching of the film in real time to ensure that the stretching ratio meets the set requirements; according to the actual situation during the stretching process, continuously optimize the process parameters, such as stretching temperature and stretching rate, to obtain a more uniform microporous structure and higher tensile strength; perform performance tests on the stretched microporous membrane, such as air permeability test and tensile strength test, and further verify and adjust the stretching ratio based on the test results. The specific steps of the air permeability test are: place the microporous membrane in the test device, allow a constant flow of gas to flow through the material, measure the time and pressure change required for the gas to pass through the material, and then calculate the air permeability. The specific steps of the tensile strength test are: place the microporous membrane in the test device, allow a constant flow of gas to flow through the material, measure the time and pressure change required for the gas to pass through the material, and then calculate the air permeability. As follows: Prepare the specimens from the polytetrafluoroethylene microporous membrane products in accordance with relevant international standards or regulations. The shape and size of the specimens must meet the test requirements. Usually, they are punched out or cut into standard shapes using a mold to ensure that the center of the specimen head is symmetrical with the center of the hole to avoid cracks and wave defects affecting the test results. Use a tensile testing machine for testing. The equipment must have high precision and stability to ensure the accuracy of the test results. Before the test, calibrate the tensile testing machine, including the setting of parameters such as force measurement accuracy and test speed. Measure the length of the specimen and record the original length. Clamp the specimen on the tensile testing machine to ensure that it is clamped tightly and will not slip. According to international standards or regulations The program conducts a tensile test, the tensile speed is 15mm / min or set according to specific requirements, stretches until the material breaks, records the maximum tension and sample length change at the time of breakage, and calculates the tensile strength based on the recorded test data. The steps for using the thickness gauge are as follows: place the thickness gauge probe on the surface of the microporous membrane to ensure good contact, start the thickness gauge, perform real-time thickness measurement, record and monitor the measurement data, and ensure that the film thickness meets the design and standard requirements. The stretching temperature parameters are adjusted as follows: use a point-shaped halogen lamp heating element to heat the microporous membrane, and control the temperature of the heating element through the sensor feedback light brightness signal, so as to achieve precise adjustment of the stretching temperature;

[0051] S4, degreasing and heat setting: the transversely stretched membrane is degreased and sintered at 380° C. for 3 minutes to obtain a heat-set film, thereby completing the preparation of the polytetrafluoroethylene microporous membrane.

[0052] Embodiment 5

[0053] The present invention provides a polytetrafluoroethylene microporous membrane with a high interception rate, comprising the following raw materials in parts by weight: 50 parts of polytetrafluoroethylene resin powder, 10 parts of paraffin oil, 5 parts of alkyl acrylate, 5 parts of ethylene oxide acrylic resin, and 10 parts of polyene succinimide;

[0054] The preparation method comprises the following steps:

[0055] S1. Mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder, paraffin oil, alkyl acrylate, ethylene oxide acrylic resin, and polyolefin succinimide to form a polytetrafluoroethylene blank;

[0056] S2. Blank pressing and calendering: The polytetrafluoroethylene blank is pressed into a cylindrical blank by a blank pressing machine, the cylindrical blank is extruded into a rod-shaped object by a push press, and then the rod-shaped object is calendered into a polytetrafluoroethylene-based tape by a calender at 60° C., so that the base tape has a width of 20 cm and a thickness of 500 μm;

[0057] S3, longitudinal stretching and transverse stretching: The polytetrafluoroethylene-based tape is longitudinally stretched in an oven at 300°C with a stretching ratio of 9 times, and the obtained base tape has a width of 17 cm and a thickness of 400 μm; then the obtained base tape is transversely stretched on a stenter at 200°C with a stretching ratio of 17 times and a speed of 10 m / min. The stretching ratio is adjusted as follows: according to the required performance and application requirements of the polytetrafluoroethylene microporous membrane, a suitable stretching ratio target is set; ensure that the stretching equipment can accurately control the stretching ratio, and achieve the target stretching ratio by adjusting the equipment parameters, such as stretching speed and temperature; during the stretching process, use The thickness gauge monitoring equipment measures the thickness and stretching of the film in real time to ensure that the stretching ratio meets the set requirements; according to the actual situation during the stretching process, the process parameters such as stretching temperature and stretching rate are continuously optimized to obtain a more uniform microporous structure and higher tensile strength; the performance tests of the stretched microporous membrane are carried out, such as air permeability test and tensile strength test, and the stretching ratio is further verified and adjusted according to the test results. The specific steps of the air permeability test are: placing the microporous membrane in the test device, allowing a constant flow of gas to flow through the material, measuring the time and pressure change required for the gas to pass through the material, and then calculating the air permeability. The specific steps of the tensile strength test are as follows: Below: Prepare the specimens from the polytetrafluoroethylene microporous membrane products according to the relevant international standards or regulations. The shape and size of the specimens must meet the test requirements. Usually, they are punched out or cut into standard shapes using a mold to ensure that the center of the specimen head is symmetrical with the center of the hole to avoid cracks and wave marks that affect the test results. Use a tensile testing machine for testing. The equipment must have high precision and stability to ensure the accuracy of the test results. Before the test, calibrate the tensile testing machine, including the setting of parameters such as force measurement accuracy and test speed. Measure the length of the specimen and record the original length. Clamp the specimen on the tensile testing machine to ensure that it is clamped tightly and will not slip. According to international standards or regulations, The tensile test is carried out in sequence, the stretching speed is 20mm / min or set according to specific requirements, stretching until the material breaks, recording the maximum tension and sample length change at the time of fracture, and calculating the tensile strength based on the recorded test data. The steps for using the thickness gauge are as follows: place the thickness gauge probe on the surface of the microporous membrane to ensure good contact, start the thickness gauge, perform real-time thickness measurement, record and monitor the measurement data, and ensure that the film thickness meets the design and standard requirements. The stretching temperature parameters are adjusted as follows: use a point-shaped halogen lamp heating element to heat the microporous membrane, and control the temperature of the heating element through the sensor feedback light brightness signal, so as to achieve precise adjustment of the stretching temperature;

[0058] S4, degreasing and heat setting: the transversely stretched membrane is degreased and sintered at 380° C. for 3 minutes to obtain a heat-set film, thereby completing the preparation of the polytetrafluoroethylene microporous membrane.

[0059] Comparative Example 1

[0060] A preparation method of a polytetrafluoroethylene microporous membrane comprises: S1, mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder and paraffin oil in a mass ratio of 100:25 for 0.5 hours, and standing at 45°C for 20 hours to form a polytetrafluoroethylene blank; S2, pressing and calendering: pressing the polytetrafluoroethylene blank into a cylindrical blank at 45°C through a blank press, and keeping the temperature for 5 minutes; extruding the cylindrical blank into a rod-shaped object through a push press at 50°C, and keeping the temperature for 5 minutes; and then calendering the rod-shaped object into a polytetrafluoroethylene-based tape through a calender at 70°C, so that the base tape width is 24 cm , thickness is 19μm, and the speed of the calender is 10 m / min; S3, longitudinal stretching and transverse stretching: the polytetrafluoroethylene based tape is longitudinally stretched in an oven at 145°C with a stretching multiple of 5 times, and the obtained base tape has a width of 19cm and a thickness of 15μm; then the obtained base tape is transversely stretched on a stenter at 145°C with a stretching multiple of 9 times and a speed of 10 m / min; S4, degreasing and heat setting: the transversely stretched film is degreased and sintered at 350°C for heat setting with a sintering time of 15 minutes to obtain a heat-set film, thereby completing the preparation of the polytetrafluoroethylene microporous membrane.

[0061] The experimental data of the polytetrafluoroethylene microporous membranes with high interception rates obtained in Examples 1 to 5 are compared with conventional polytetrafluoroethylene microporous membranes, as shown in the following table:

[0062]

[0063] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A polytetrafluoroethylene microporous membrane with high interception rate, characterized in that: The invention comprises the following raw materials in parts by weight: 40-50 parts of polytetrafluoroethylene resin powder, 1-10 parts of paraffin oil, 1-5 parts of alkyl acrylate, 1-5 parts of ethylene oxide acrylic resin and 5-10 parts of polyene succinimide.

2. A polytetrafluoroethylene microporous membrane with high interception rate according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 40 parts of polytetrafluoroethylene resin powder, 1 part of paraffin oil, 1 part of alkyl acrylate, 1 part of ethylene oxide acrylic resin and 5 parts of polyene succinimide.

3. A polytetrafluoroethylene microporous membrane with high interception rate according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 45 parts of polytetrafluoroethylene resin powder, 5 parts of paraffin oil, 3 parts of alkyl acrylate, 3 parts of ethylene oxide acrylic resin and 7 parts of polyene succinimide.

4. A polytetrafluoroethylene microporous membrane with high interception rate according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 50 parts of polytetrafluoroethylene resin powder, 10 parts of paraffin oil, 5 parts of alkyl acrylate, 5 parts of ethylene oxide acrylic resin and 10 parts of polyene succinimide.

5. A method for preparing a polytetrafluoroethylene microporous membrane with a high interception rate, characterized in that: The following steps are involved: S1. Mixing: uniformly stirring and mixing polytetrafluoroethylene resin powder, paraffin oil, alkyl acrylate, ethylene oxide acrylic resin, and polyolefin succinimide to form a polytetrafluoroethylene blank; S2, blank pressing and calendering: the polytetrafluoroethylene blank is pressed into a cylindrical blank by a blank pressing machine, the cylindrical blank is extruded into a rod-shaped object by a push press, and then the rod-shaped object is calendered into a polytetrafluoroethylene-based tape by a calender at 60° C., so that the base tape has a width of 17-20 cm and a thickness of 500 μm; S3, longitudinal stretching and transverse stretching: longitudinally stretch the polytetrafluoroethylene tape in an oven at 260-300°C, with a stretching ratio of 7-9 times, and the obtained base tape has a width of 13-17 cm and a thickness of 300-400 μm; then, transversely stretch the obtained base tape on a stenter at 140-200°C, with a stretching ratio of 14-17 times and a speed of 10 m / min; S4, degreasing and heat setting: the transversely stretched film is degreased and sintered at 380°C for heat setting. The sintering time is 2-3 minutes to obtain a heat-set film, thereby completing the preparation of the polytetrafluoroethylene microporous membrane.

6. The method for preparing a polytetrafluoroethylene microporous membrane with high interception rate according to claim 5, characterized in that: The stretching ratio is adjusted as follows: according to the required performance and application requirements of the polytetrafluoroethylene microporous membrane, set a suitable stretching ratio target; ensure that the stretching equipment can accurately control the stretching ratio, and achieve the target stretching ratio by adjusting the parameters of the equipment; During the stretching process, a thickness gauge monitoring device is used to measure the thickness and stretching of the film in real time to ensure that the stretching ratio meets the set requirements; According to the actual situation during the stretching process, the process parameters are continuously optimized to obtain a more uniform microporous structure and higher tensile strength; the performance of the microporous membrane after stretching is tested, and the stretching ratio is further verified and adjusted based on the test results.

7. The method for preparing a polytetrafluoroethylene microporous membrane with a high interception rate according to claim 6, characterized in that: The specific steps of the air permeability test are: placing the microporous membrane in a test device, allowing a constant flow of gas to flow through the material, measuring the time and pressure change required for the gas to pass through the material, and then calculating the air permeability.

8. The method for preparing a polytetrafluoroethylene microporous membrane with a high interception rate according to claim 6, characterized in that: The tensile strength test is as follows: Prepare specimens from polytetrafluoroethylene microporous membrane products in accordance with relevant international standards or regulations. The shape and size of the specimens must meet the test requirements. They are usually punched out or cut into standard shapes using a mold to ensure that the center of the specimen head is symmetrical with the center of the hole to avoid cracks and wave defects affecting the test results. Use a tensile testing machine for testing. The equipment must have high precision and stability to ensure the accuracy of the test results. Before the test, calibrate the tensile testing machine, measure the length of the specimen and record the original length, clamp the specimen on the tensile testing machine, ensure that it is clamped and will not slip, and perform a tensile test according to international standards or prescribed procedures. The stretching speed is 10-20mm / min or set according to specific requirements. Stretch until the material breaks, record the maximum tension and specimen length change at break, and calculate the tensile strength based on the recorded test data.

9. The method for preparing a polytetrafluoroethylene microporous membrane with high interception rate according to claim 6, characterized in that: The steps for using the thickness gauge are as follows: place the thickness gauge probe on the surface of the microporous membrane to ensure good contact, start the thickness gauge, perform real-time thickness measurement, record and monitor the measurement data, and ensure that the film thickness meets the design and standard requirements.

10. The method for preparing a polytetrafluoroethylene microporous membrane with a high interception rate according to claim 6, characterized in that: The stretching temperature parameters are adjusted as follows: the microporous membrane is heated using a point-shaped halogen lamp heating element, and the temperature of the heating element is controlled by feedback of a light brightness signal from a sensor, thereby achieving precise adjustment of the stretching temperature.

Images