Preparation method of size-controllable reinforced polytetrafluoroethylene particles
By mixing the polytetrafluoroethylene powder with solvent oil and forming it in an ultra-high pressure forming equipment, combining crushing and separation technology, polytetrafluoroethylene particles with controllable size are prepared, and the size uncontrollable and crystallized in the prior art are solved. The problem of low degree has achieved pore size adjustment and particle performance stability of nano-scale porous membranes.
Patent Information
- Application Number
- CN202411549560.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-01-07
AI Technical Summary
The prior art is difficult to prepare polytetrafluoroethylene particles with controllable size and strengthening, which cannot meet the pore size adjustment requirements of nano-scale porous membranes. The raw material has low crystallinity and high elongation, but is not suitable for the preparation of nano-scale porous membranes.
By mixing the polytetrafluoroethylene powder with solvent oil in a certain proportion, the solvent oil is removed after forming a wet embryo body, and then forming it in an ultra-high pressure forming equipment. Finally, a particle size of 50-500nm is prepared by crushing and separation technology. and the particle size can be finely adjusted by repeating steps.
The controllability of the particle size and crystallinity of polytetrafluoroethylene particles is achieved, the stability and purity of the material are ensured, the precipitation of particulate matter is avoided, and the preparation needs of nano-scale porous membranes are met.
Abstract
Description
Technical Field
[0001] The invention relates to the field of preparation of size-controllable reinforced polytetrafluoroethylene particles, and in particular to a preparation process for reinforced and crushed polytetrafluoroethylene particles. Background Art
[0002] Dispersed polytetrafluoroethylene raw materials are agglomerates of 0.2-0.5 micron particles with a size of about 500 microns. The raw material has low crystallinity and high elongation. It is used to produce fiber and node structures in biaxial stretching to form micropores, but is not suitable for pore size adjustment particles for nano-scale porous membranes. Summary of the invention
[0003] The invention relates to a method for preparing size-controllable, reinforced polytetrafluoroethylene particles. The reinforced polytetrafluoroethylene particles produced by the process have uniform and controllable particle size, controllable strength, stable chemical properties, and a single and pure material, and are suitable for the preparation process of nano-scale multi-pore polytetrafluoroethylene membranes.
[0004] The specific technical solutions of the present invention are as follows: A method for preparing size-controlled, reinforced polytetrafluoroethylene particles, comprising the following steps: (1) Mix polytetrafluoroethylene (PTFE) powder and solvent oil in a certain proportion; (2) Put the mixed material into a low-temperature cylinder and form a PTFE wet embryo through unidirectional or bidirectional extrusion; (3) placing the wet embryo in a degreasing oven and slowly heating it to remove the solvent oil to form a dry embryo; (4) Fixing the dry embryo body in a designed rubber mold, placing it in an ultra-high pressure molding device, preheating it at a certain temperature and within a certain time range, and then press-molding it to form a preform; (5) The preform is crushed into small particles; (6) Through separation technology, the tiny particles are screened into the required size, with a particle size between 50-500nm; (7) The polytetrafluoroethylene (PTFE) particles of a preset outer size can be prepared a second time by repeating the above steps to obtain particles of a desired size.
[0005] The mass ratio of the polytetrafluoroethylene powder to the solvent oil in step (1) is between 1:0.1 and 1:0.3.
[0006] In step (2), the temperature of the low-temperature cylinder is 15-60°C. After the mixed material is placed in the cylinder, it can be extruded in one direction, extruded in two directions at the same time, or extruded in two directions in stages. The pressure range is between 0.05Mpa and 0.5Mpa.
[0007] The degreasing oven temperature in step (3) is 100-250°C, and the time for removing the solvent oil is more than 1 minute.
[0008] The ultra-high pressure molding equipment in step (4) includes an isostatic press, a high-density press-fitting equipment, and a hot pressing molding equipment. The certain temperature range is between 150-400°C, the certain time is between 10min-30min, and the pressure is between 5-30Mpa.
[0009] The crushing process in step (5) includes jaw crushing process, roller grinding technology, ultrafine grinding process, and nano-depolymerization process.
[0010] The separation techniques in step (6) include mechanical separation, ultrasonic separation, membrane separation technology, magnetic separation technology, dielectrophoresis technology, electrophoresis technology, and laser optical tweezers technology.
[0011] The advantages of the present invention are: 1) The polytetrafluoroethylene particles prepared by a size-controllable and reinforced polytetrafluoroethylene particle preparation method have a controllable particle size between 5 and 500 nm, which can meet the process requirements for preparing micropores with different pore sizes.
[0012] 2) The polytetrafluoroethylene particles prepared by a method for preparing size-controlled, reinforced polytetrafluoroethylene particles have controllable crystallinity, and the bonding force between the particles and the fibers is high in the process of preparing nano-scale porous membranes, and no peeling phenomenon occurs.
[0013] 3) The polytetrafluoroethylene particles prepared by a size-controllable and reinforced polytetrafluoroethylene particle preparation method have stable performance, uniform material, no particle precipitation, and purity that meets the requirements of the ultra-clean reagent purification industry. DETAILED DESCRIPTION Example 1
[0014] 1) Mix polytetrafluoroethylene powder and solvent oil in a mass ratio of 1:0.1; 2) Put the mixture into a 15°C low-temperature cylinder, and form a wet embryo through bidirectional extrusion at a pressure of 0.05Mpa; 3) Put the wet embryo into a 100°C degreasing oven and slowly heat it for 30 minutes to remove the solvent oil to form a dry embryo; 4) Fix the dry embryo in a rubber mold, place it in an isostatic pressing device, preheat it at 150°C, pressure 30Mpa, and then slowly press it for 10 minutes to form a preform; 5) The preform is made into tiny particles through a nano-depolymerization process; 6) The tiny particles are screened out to a size of 50nm through dielectrophoresis technology; 7) Polytetrafluoroethylene particles of a preset outer size can be secondary prepared by repeating the above steps to obtain particles of the required size. Example 2
[0015] 1) Mix polytetrafluoroethylene powder and solvent oil in a mass ratio of 1:0.2; 2) Put the mixture into a 40°C low-temperature cylinder, and form a wet embryo through bidirectional extrusion at a pressure of 0.12Mpa; 3) Put the wet embryo into a 130°C degreasing oven and slowly heat it for 30 minutes to remove the solvent oil to form a dry embryo; 4) Fix the dry embryo in a rubber mold, place it in an isostatic pressing device, preheat it at 400°C, pressure 20Mpa, and then slowly press it for 10 minutes to form a preform; 5) The preform is made into tiny particles through an ultrafine grinding process; 6) Through ultrasonic separation, the tiny particles are screened out to a size of 80nm; 7) Polytetrafluoroethylene particles of a preset outer size can be secondary prepared by repeating the above steps to obtain particles of the required size. Example 3
[0016] 1) Mix tetrafluoroethylene (PTFE) powder and solvent oil in a mass ratio of 1:0.3; 2) Put the mixture into a 60°C low-temperature cylinder, and form a tetrafluoro wet embryo through bidirectional extrusion at a pressure of 0.5Mpa; 3) Put the wet embryo into a 250°C degreasing oven and slowly heat it for 30 minutes to remove the solvent oil to form a dry embryo; 4) Fix the dry embryo in a designed rubber mold, place it in an isostatic pressing device, preheat it at 100°C, pressure 5Mpa, and then slowly press it for 10 minutes to form a preform; 5) The preform is made into tiny particles through roller milling technology; 6) Through magnetic separation technology, the tiny particles are screened out to a size of 500nm; 7) The tetrafluoroethylene particles of the preset outer size can be secondary prepared by repeating the above steps to obtain particles of the required size.
Claims
1. A method for preparing size-controlled reinforced polytetrafluoroethylene particles, characterized in that: The following steps are included: (1) Mix polytetrafluoroethylene powder and solvent oil in a certain proportion; (2) Put the mixed material into a low-temperature cylinder and form a PTFE wet embryo through unidirectional or bidirectional extrusion; (3) placing the wet embryo in a degreasing oven and slowly heating it to remove the solvent oil to form a dry embryo; (4) Fixing the dry embryo body in a rubber mold, placing it in an ultra-high pressure molding device, preheating it within a certain temperature and time range, and then pressurizing it to form a preform; (5) The preform is crushed into small particles; (6) Through separation technology, the tiny particles are screened into the required size, with a particle size between 50-500nm; (7) The polytetrafluoroethylene particles of the preset outer size can be prepared for a second time by repeating the above steps to obtain particles of the desired size.
2. The method for preparing size-controlled reinforced polytetrafluoroethylene particles according to claim 1, characterized in that: The mass ratio of polytetrafluoroethylene powder to solvent oil in step (1) is between 1:0.1 and 1:0.
3.
3. The method for preparing size-controlled reinforced polytetrafluoroethylene particles according to claim 1, characterized in that: In step (2), the temperature of the low-temperature cylinder is 15-60°C. After the mixed material is placed in the cylinder, unidirectional extrusion, bidirectional simultaneous extrusion or bidirectional segmented extrusion is performed, and the pressure range is between 0.05Mpa and 0.5Mpa.
4. The method for preparing size-controlled reinforced polytetrafluoroethylene particles according to claim 1, characterized in that: The degreasing oven temperature in step (3) is 100-250°C, and the time for removing the solvent oil is more than 1 minute.
5. The method for preparing size-controlled reinforced polytetrafluoroethylene particles according to claim 1, characterized in that: In step (4), the ultra-high pressure molding equipment includes an isostatic press, a high-density press-fitting equipment, and a hot pressing molding equipment; the temperature range is between 150-400°C, the time is between 10min-30min, and the pressure is between 5-30Mpa.
6. The method for preparing size-controlled reinforced polytetrafluoroethylene particles according to claim 1, characterized in that: The crushing process in step (5) includes jaw crushing process, roller grinding technology, ultrafine grinding process, and nano-depolymerization process.
7. The method for preparing size-controlled reinforced polytetrafluoroethylene particles according to claim 1, characterized in that: The separation techniques in step (6) include mechanical separation, ultrasonic separation, membrane separation technology, magnetic separation technology, dielectrophoresis technology, electrophoresis technology, and laser optical tweezers technology.