Method for preparing polymer micro porous film

A polymer, microporous film technology, applied in flat products, applications, household appliances, etc., can solve the problems of uneven micropores, slow growth of wafers, and high melt viscosity

Inactive Publication Date: 2007-01-24
闫里选 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If a polymer with a higher molecular weight is selected, although the molecular chain is easy to be oriented when the melt is drawn, the melt viscosity is high, the growth rate of the wafer is slow, and it is easy to form a microfibrous structure. The transverse tensile strength of the film is low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The F600 film-grade polypropylene produced by Yanshan Petrochemical Company (230°C, 2.16kg melt index is 10 g / 10min) and Yanshan Petrochemical's model 1300 polypropylene (230°C, 2.16kg melt index is 1.5 g / 10min) in a weight ratio of 80 / 20. After melt blending and pelletizing with a twin-screw extruder, it was added to a single-screw extruder casting film-making device with a diameter of 45 mm and an aspect ratio of 25. A film with a thickness of 20 μm was prepared under the same conditions, and the obtained film was heat-treated (annealed) in an oven at 140° C. The tensile elastic recovery rates at different times were shown in Table 1. The annealed films were stretched 25% at room temperature, then stretched to 100% at 120°C, and then heat-set at 140°C for 5 minutes. The resulting air permeability data for the microporous films are also listed in Table 1. The test conditions for tensile elastic recovery rate are as follows: Tensile samples are prepared according to G...

Embodiment 2

[0020] The high-density polyethylene 2200J of Yangzi Petrochemical (melt flow rate 5.8g / 10min, density 0.968g / cm 3 ) and the high-density polyethylene 5000S of Yangzi Petrochemical (melt flow rate 0.8g / 10min, density 0.952g / cm 3 ) in a 60 / 40 weight ratio. After melt blending and pelletizing with a twin-screw extruder, it was added to a single-screw extruder casting film-making device with a diameter of 45 mm and an aspect ratio of 25. A film with a thickness of 20 μm was prepared under the conditions. The obtained film was heat-treated in an oven at 110°C for 20 minutes, then stretched to 150% at room temperature, and heat-set at 120°C for 10 minutes. The air permeability of the obtained microporous film was 250 ml / cm 2 ·s·MPa, the elastic recovery rate of the microporous membrane precursor is 42%. The air permeability of the microporous film prepared under the same conditions with HDPE 2200J without blending HDPE 5000S is 78ml / cm 2 ·s·MPa, the elastic recovery rate of the...

Embodiment 3

[0022] The above-mentioned film grade polypropylene resin of type F600 produced by Yanshan Petrochemical Company and polypropylene resin of type 1300 produced by Yanshan Petrochemical were mixed in a weight ratio of 60 / 40. The microporous membrane was prepared by the same method and the same processing conditions as in Example 1 (annealing time was 10 minutes), and the air permeability of the obtained microporous membrane was 65 ml / cm 2 ·s·MPa, the elastic recovery rate of the microporous membrane precursor is 91%, the longitudinal tensile strength of the microporous membrane is 1450 MPa, and the transverse tensile strength is 137 MPa. As a reference example, the air permeability of the microporous membrane obtained by mixing the resin in the ratio of 45 / 55 by the same method and the same processing conditions is 62ml / cm 2 ·s·MPa, the elastic recovery rate of the microporous membrane precursor reaches 92%, but the transverse tensile strength of the microporous membrane is only...

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Abstract

The present invention belongs to the field of polymer film preparing technology, and is especially extruding and stretching process for preparing crystalline microporous polymer film. High molecular weight crystalline polymer and low molecular weight crystalline polymer in certain ratio are molten and blended, the mixture is fusing extruded and quick stretched to obtain the microporous film precursor, and the microporous film precursor is annealed, stretched and settled to obtain the microporous polymer film. The technological process has relatively relaxed conditions, and the prepared film has average pore size of 0.05-0.4 micron and high air permeability and may find its wide application in water treatment, micro filtering, artificial lung, cell diaphragm, etc.

Description

technical field [0001] The invention belongs to the technical field of preparation of polymer films, and particularly relates to an extrusion stretching preparation method of a crystalline polymer microporous film. Background technique [0002] The polymer microporous membrane is a polymer film with numerous interconnected micropores and a pore size of 0.01 to 10 μm. The preparation methods mainly include thermally induced phase separation, solution precipitation, extrusion stretching and other methods. The extrusion stretching method is suitable for crystalline polymers, such as polyethylene, polypropylene, poly-4-methylpentene, polyoxymethylene, polyvinylidene fluoride, and the like. The principle is to melt extrude the polymer, crystallize the polymer at a higher draw ratio, and then stretch the film to form micropores. The advantage of this method is that no solvent or precipitant is introduced in the preparation process, a microporous membrane with high purity can be ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C69/00B29C47/12B29C55/02B29C71/02B29B9/02B29K23/00B29K27/12B29K61/00B29L7/00B29C48/30
Inventor 闫里选杜强国葛昌杰潘宝荣钟伟王海涛
Owner 闫里选
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