CN102529291B - Bonding method for polytetrafluoroethylene cellular material - Google Patents

Abstract

The invention discloses a bonding method for polytetrafluoroethylene microporous materials. The present invention mixes polytetrafluoroethylene resin powder with aviation kerosene, and prepares polytetrafluoroethylene microporous film through processes such as extrusion, calendering, and longitudinal stretching; the multilayer polytetrafluoroethylene microporous film, or polytetrafluoroethylene The microporous film is wrapped on the outside of the polytetrafluoroethylene hollow fiber membrane and hot pressed at high temperature. The invention does not use an adhesive, can ensure that the final material is 100% polytetrafluoroethylene, and will not change the physical properties of the material. The process in the invention is simple and low in cost, and can be used not only for bonding between polytetrafluoroethylene microporous films, but also for wrapping polytetrafluoroethylene hollow fiber membranes with polytetrafluoroethylene microporous films.

Description

A kind of bonding method of polytetrafluoroethylene microporous material

technical field

The invention relates to a preparation method of a polymer material, in particular to a bonding method of a polytetrafluoroethylene microporous material.

Background technique

PTFE microporous materials can be processed by stretching PTFE resin, and can be processed into thin film, hollow fiber membrane and other shapes by using different equipment and processes. PTFE material has the characteristics of waterproof, high temperature resistance, acid and alkali resistance, and corrosion resistance. At the same time, the PTFE microporous material processed by stretching method has the characteristics of developed porosity, easy control of micropore size, and low apparent density. Therefore, PTFE microporous materials are widely used as waterproof and moisture-permeable fabrics, air filter materials, water filter materials, sealing materials, etc.

When used as a waterproof and breathable fabric, one of the important indicators is water pressure resistance; when used as an air and water filter material, one of the important indicators is the filtration accuracy; studies have shown that water pressure resistance and filtration accuracy are related to the size of the pore size. In order to reduce the pore size, the multi-layer polytetrafluoroethylene microporous materials are bonded together, and the crossing between the micropores can achieve the purpose of reducing the pore size. When used as a sealing material, in order to achieve the preset thickness of the sealing material, it is also necessary to bond multiple layers of microporous films together. For the hollow fiber membrane material used in water treatment, in order to reduce the pore size, it is also necessary to wrap a layer of polytetrafluoroethylene microporous flat membrane on the outside of the polytetrafluoroethylene hollow fiber membrane to improve the interception efficiency of small particles.

Therefore, it is necessary to bond multilayer polytetrafluoroethylene microporous materials in many fields. The traditional method is mostly adhesive bonding, so that the final material will sacrifice some of the characteristics of the PTFE material itself.

Our authorized invention patent "A preparation method of polytetrafluoroethylene film material for air sterilization, patent number ZL200510061828.9" discloses a two-layer polytetrafluoroethylene processing method: the polytetrafluoroethylene resin powder It is mixed with liquid lubricant and processed through extrusion, calendering, two-layer simultaneous longitudinal stretching, transverse stretching and heat setting. The method is mainly to stretch two layers of polytetrafluoroethylene base tapes longitudinally at the same time, and achieve the purpose of bonding through subsequent processing.

Contents of the invention

The object of the present invention is to provide a bonding method for polytetrafluoroethylene microporous materials, which is to mix polytetrafluoroethylene resin powder with aviation kerosene, and prepare polytetrafluoroethylene through processes such as extrusion, calendering, and longitudinal stretching. Microporous film: It is formed by wrapping multi-layer polytetrafluoroethylene microporous film, or polytetrafluoroethylene microporous film on the outside of polytetrafluoroethylene hollow fiber membrane, and hot pressing at high temperature.

The technical scheme adopted in the present invention is:

It is characterized in that comprising the steps of:

(1) Polytetrafluoroethylene microporous film: mix polytetrafluoroethylene resin powder with a weight ratio of 1:0.2~0.28 and aviation kerosene, let it stand at a temperature of 20~40°C for 96~144 hours, and then dry it at 40 Stand at ~80°C for 10-16 hours to fully mix the polytetrafluoroethylene resin powder and aviation kerosene to form a polytetrafluoroethylene material; place the polytetrafluoroethylene material at 20-30°C in The cylindrical blank is pressed on the compacting machine, and the cylindrical blank is extruded into a rod at a temperature of 40~60°C through a pusher, and then the rod is rolled into a polytetrafluoroethylene base tape at a temperature of 40~60°C through a calender ; Stretching the polytetrafluoroethylene base tape longitudinally by 2 to 5 times in an oven at 180 to 220 ° C to obtain a polytetrafluoroethylene microporous film with a thickness of 5 microns to 80 microns;

(2) Bonding between polytetrafluoroethylene microporous materials: laminate the multi-layer polytetrafluoroethylene microporous films and perform hot pressing; or wrap the polytetrafluoroethylene microporous films in The outer side of the polytetrafluoroethylene hollow fiber membrane is hot-pressed to achieve bonding between polytetrafluoroethylene microporous materials.

The polytetrafluoroethylene resin powder has a crystallinity of 98-99.9% and a molecular weight of 2×10 ⁶ to 1×10 ⁷ .

The polytetrafluoroethylene microporous film contains aviation kerosene, and the weight ratio of the polytetrafluoroethylene microporous film to aviation kerosene is 1:0.03-0.15.

The polytetrafluoroethylene hollow fiber membrane contains aviation kerosene, and the weight ratio of the polytetrafluoroethylene hollow fiber membrane to aviation kerosene is 1:0.03-0.15.

The hot pressing temperature is 280-350° C., the time is 0.8-30 seconds, and the pressure is 1-5 kgf/cm2.

The present invention compares with background technology, the beneficial effect that the present invention has is:

(1) The present invention mainly controls the oil content in the polytetrafluoroethylene microporous material, and realizes the bonding between polytetrafluoroethylene and polytetrafluoroethylene under certain temperature and pressure. The bonding mechanism is due to the fact that PTFE can form a "fibril-node" microstructure under external force and a certain temperature, which contains some lubricants (such as aviation kerosene) that can promote the bonding between PTFE materials. Interpenetration and fusion, so as to achieve the bonding between PTFE and PTFE without using any adhesive.

(2) The present invention does not use adhesives, which can ensure that the final material is 100% polytetrafluoroethylene, and the physical properties of the material will not be changed.

The invention has simple process and low cost, not only can be used for bonding between polytetrafluoroethylene microporous membranes, but also can be used for polytetrafluoroethylene microporous membranes to wrap polytetrafluoroethylene hollow fiber membranes.

Detailed ways

Example 1:

(1) Polytetrafluoroethylene microporous film: Mix F106 polytetrafluoroethylene resin powder and aviation kerosene (the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is 1:0.2) from Daikin Company, Japan, and mix them evenly at 20 °C. Stand still at a temperature of 96 hours, and then stand at a temperature of 40°C for 10 hours to fully mix the resin powder and aviation kerosene to form a polytetrafluoroethylene material; put the polytetrafluoroethylene material at 20°C, Press the blank into a cylindrical blank on a compactor, extrude the blank into a rod at a temperature of 40°C through a pusher, and then roll it into a polytetrafluoroethylene base tape at a temperature of 40°C through a calender; the polytetrafluoroethylene The base tape is stretched 5 times longitudinally in an oven at 220°C to obtain a polytetrafluoroethylene microporous film with a thickness of 5 microns. The weight ratio is 1:0.03;

(2) Bonding between polytetrafluoroethylene microporous materials: The two layers of polytetrafluoroethylene microporous films are laminated and hot-pressed. The hot-pressing temperature is 280°C, the time is 30 seconds, and the pressure is 1 kgf/cm2, to achieve the bonding of multi-layer polytetrafluoroethylene microporous films.

Example 2:

(1) Polytetrafluoroethylene microporous film: Mix 188 polytetrafluoroethylene resin powder produced by Zhejiang Juhua Group and aviation kerosene (the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is 1:0.28). Stand still at a temperature of 40°C for 144 hours, then stand at a temperature of 80°C for 16 hours to fully mix the resin powder and aviation kerosene to form a polytetrafluoroethylene material; put the polytetrafluoroethylene material at 30°C Press the blank into a cylindrical blank on a compacting machine, extrude the blank into a rod at a temperature of 60°C through a pusher, and then roll it into a polytetrafluoroethylene base tape at a temperature of 60°C through a calender; the polytetrafluoroethylene The fluoroethylene base tape is longitudinally stretched 2 times in an oven at 180°C to obtain a PTFE microporous film with a thickness of 80 microns. The PTFE microporous film contains part of aviation kerosene, and PTFE resin powder is good for aviation The weight ratio of kerosene is 1:0.15;

(2) Bonding between polytetrafluoroethylene microporous materials: The 100 layers of polytetrafluoroethylene microporous films are laminated and hot-pressed. The hot-pressing temperature is 350°C, the time is 0.8 seconds, and the pressure is 5 kgf/cm2, to achieve the bonding of multi-layer polytetrafluoroethylene microporous films.

Example 3:

(1) Polytetrafluoroethylene microporous film: Mix 188 polytetrafluoroethylene resin powder produced by Zhejiang Juhua Group and aviation kerosene (the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is 1:0.22). Stand still at a temperature of 30°C for 120 hours, and then stand at a temperature of 60°C for 12 hours to fully mix the resin powder and aviation kerosene to form a polytetrafluoroethylene material; put the polytetrafluoroethylene material at 25°C Press the blank into a cylindrical blank on a compacting machine, extrude the blank into a rod at a temperature of 50°C through a pusher, and then roll it into a polytetrafluoroethylene base tape at a temperature of 50°C through a calender; the polytetrafluoroethylene The fluoroethylene base tape is longitudinally stretched 3 times in an oven at 200 ° C to obtain a polytetrafluoroethylene microporous film with a thickness of 50 microns. The polytetrafluoroethylene microporous film contains part of aviation kerosene. The weight ratio of kerosene is 1:0.1;

(2) Bonding between polytetrafluoroethylene microporous materials: Laminate the 50 layers of polytetrafluoroethylene microporous films and perform hot pressing at a temperature of 300°C for 20 seconds and a pressure of 3 kgf/cm2, to achieve the bonding of multi-layer polytetrafluoroethylene microporous films.

Example 4:

(1) Polytetrafluoroethylene microporous film: Mix F106 polytetrafluoroethylene resin powder and aviation kerosene (the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is 1:0.2) from Daikin Company, Japan, and mix them evenly at 20 °C. Stand still at a temperature of 96 hours, and then stand at a temperature of 40°C for 10 hours to fully mix the resin powder and aviation kerosene to form a polytetrafluoroethylene material; put the polytetrafluoroethylene material at 20°C, Press the blank into a cylindrical blank on a compactor, extrude the blank into a rod at a temperature of 40°C through a pusher, and then roll it into a polytetrafluoroethylene base tape at a temperature of 40°C through a calender; the polytetrafluoroethylene The base tape is stretched 5 times longitudinally in an oven at 220°C to obtain a polytetrafluoroethylene microporous film with a thickness of 5 microns. The weight ratio is 1:0.03;

(2) Bonding between polytetrafluoroethylene microporous materials: wrap the polytetrafluoroethylene microporous membrane on the outside of the polytetrafluoroethylene hollow fiber membrane, and the polytetrafluoroethylene hollow fiber membrane contains For some aviation kerosene, the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is controlled to be 1:0.03, and the device in "a polytetrafluoroethylene hollow fiber stretching device, application number 201010508798.2" is used for processing; finally, hot pressing , the hot pressing temperature is 280° C., the time is 30 seconds, and the pressure is 1 kgf/cm2, so as to achieve the bonding between the polytetrafluoroethylene microporous membrane and the polytetrafluoroethylene hollow fiber membrane.

Example 5:

(1) Polytetrafluoroethylene microporous film: Mix 188 polytetrafluoroethylene resin powder produced by Zhejiang Juhua Group and aviation kerosene (the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is 1:0.28). Stand still at a temperature of 40°C for 144 hours, then stand at a temperature of 80°C for 16 hours to fully mix the resin powder and aviation kerosene to form a polytetrafluoroethylene material; put the polytetrafluoroethylene material at 30°C Press the blank into a cylindrical blank on a compacting machine, extrude the blank into a rod at a temperature of 60°C through a pusher, and then roll it into a polytetrafluoroethylene base tape at a temperature of 60°C through a calender; the polytetrafluoroethylene The fluoroethylene base tape is longitudinally stretched 2 times in an oven at 180°C to obtain a PTFE microporous film with a thickness of 80 microns. The PTFE microporous film contains part of aviation kerosene, and PTFE resin powder is good for aviation The weight ratio of kerosene is 1:0.15;

(2) Bonding between polytetrafluoroethylene microporous materials: wrap the polytetrafluoroethylene microporous membrane on the outside of the polytetrafluoroethylene hollow fiber membrane, and the polytetrafluoroethylene hollow fiber membrane contains For some aviation kerosene, the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is controlled to be 1:0.15, and the device in "a polytetrafluoroethylene hollow fiber stretching device, application number 201010508798.2" is used for processing; finally, hot pressing , the hot pressing temperature is 350° C., the time is 0.8 seconds, and the pressure is 5 kgf/cm2, so as to achieve the bonding between the polytetrafluoroethylene microporous membrane and the polytetrafluoroethylene hollow fiber membrane.

Embodiment 6:

(1) Polytetrafluoroethylene microporous film: Mix 188 polytetrafluoroethylene resin powder produced by Zhejiang Juhua Group and aviation kerosene (the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is 1:0.22). Stand still at a temperature of 30°C for 120 hours, and then stand at a temperature of 60°C for 12 hours to fully mix the resin powder and aviation kerosene to form a polytetrafluoroethylene material; put the polytetrafluoroethylene material at 25°C Press the blank into a cylindrical blank on a compacting machine, extrude the blank into a rod at a temperature of 50°C through a pusher, and then roll it into a polytetrafluoroethylene base tape at a temperature of 50°C through a calender; the polytetrafluoroethylene The fluoroethylene base tape is longitudinally stretched 3 times in an oven at 200 ° C to obtain a polytetrafluoroethylene microporous film with a thickness of 50 microns. The polytetrafluoroethylene microporous film contains part of aviation kerosene. The weight ratio of kerosene is 1:0.1;

(2) Bonding between polytetrafluoroethylene microporous materials: wrap the polytetrafluoroethylene microporous membrane on the outside of the polytetrafluoroethylene hollow fiber membrane, and the polytetrafluoroethylene hollow fiber membrane contains For some aviation kerosene, the weight ratio of polytetrafluoroethylene resin powder to aviation kerosene is controlled to be 1:0.12, and the device in "a polytetrafluoroethylene hollow fiber stretching device, application number 201010508798.2" is used for processing; finally, hot pressing , the hot pressing temperature is 300° C., the time is 20 seconds, and the pressure is 3 kgf/cm2, so as to achieve the bonding between the polytetrafluoroethylene microporous membrane and the polytetrafluoroethylene hollow fiber membrane.

Claims (3)

1. an adhesive method for polytetrafluoroethylene (PTFE) poromerics, is characterized in that comprising the steps:

(1) polytetrafluoroethylmicroporous microporous membrane: the teflon resin powder that is 1:0.2～0.28 by weight ratio and aviation kerosine are mixed, at the temperature of 20 ~ 40 DEG C, leave standstill 96 ~ 144 hours, then at the temperature of 40 ~ 80 DEG C, leave standstill 10 ~ 16 hours, make teflon resin powder, aviation kerosine fully mixed, form polytetrafluoroethylene (PTFE) material; By described polytetrafluoroethylene (PTFE) material at 20 ~ 30 DEG C, on harder, be pressed into cylindrical blank, cylindrical blank is extruded to club by pushing machine at the temperature of 40 ~ 60 DEG C, then club is rolled into polytetrafluoroethylene (PTFE) base band through calender at 40 ~ 60 DEG C; Described polytetrafluoroethylene (PTFE) base band is carried out to 2～5 times of longitudinal stretchings in the baking oven of 180 ~ 220 DEG C, and obtaining thickness is 5 microns ~ 80 microns polytetrafluoroethylmicroporous microporous membranes;

(2) bonding between polytetrafluoroethylene (PTFE) poromerics: by superimposed described polytetrafluoroethylmicroporous microporous membrane, carry out hot pressing; Or described polytetrafluoroethylmicroporous microporous membrane looping, in polytetrafluoroethylhollow hollow fiber membrane outside, is carried out to hot pressing, reach the bonding between polytetrafluoroethylene (PTFE) poromerics;

Described polytetrafluoroethylmicroporous microporous membrane contains aviation kerosine, and polytetrafluoroethylmicroporous microporous membrane is 1:0.03～0.15 to the weight ratio of aviation kerosine;

Described polytetrafluoroethylhollow hollow fiber membrane contains aviation kerosine, and polytetrafluoroethylhollow hollow fiber membrane is 1:0.03～0.15 to the weight ratio of aviation kerosine.

2. the adhesive method of a kind of polytetrafluoroethylene (PTFE) poromerics according to claim 1, is characterized in that: the degree of crystallinity of described teflon resin powder is 98 ~ 99.9%, and molecular weight is 2 × 10 ⁶~ 1 × 10 ⁷.

3. the adhesive method of a kind of polytetrafluoroethylene (PTFE) poromerics according to claim 1, is characterized in that: described hot pressing temperature is 280～350 DEG C, and the time is 0.8～30 second, and pressure is 1～5 kilogram/square centimeter.