Two-way stretching mold for polytetrafluoroethylene hollow fibrous membrane

Abstract

The invention discloses a two-way stretching mold for a polytetrafluoroethylene hollow fibrous membrane. The mold comprises an outer mold, a core mold, an expanding outer mold and an expanding core mold; an outer mold through hole penetrating through frontward and backward is dug in the outer mold; the core mold is fixedly installed in the outer mold through hole; a longitudinal stretching throughpassage with the back wide section and the front narrow section is formed between the outer mold and the core mold; the expending outer mold is installed on the front end portion of the outer mold; an expanding outer mold through hole penetrating through frontward and backward is dug in the expanding outer mold; the expanding core mold is installed on the front end portion of the core mold; the expanding core mold is fixedly installed in the expanding outer mold through hole of the expanding outer mold; a vertical and horizontal two-way stretching passage with the same width is formed betweenthe expanding outer mold and the expanding core mold; the longitudinal stretching passage is communicated with the vertical and horizontal two-way stretching passage. The polytetrafluoroethylene hollow fibrous membrane is stretched transversely and longitudinally, and therefore the polytetrafluoroethylene hollow fibrous membrane with the smaller hole diameter and high porosity can be obtained simply and efficiently.

Description

technical field [0001] The invention relates to a stretching die for a hollow fiber membrane, in particular to a bidirectional stretching die for a polytetrafluoroethylene hollow fiber membrane. Background technique [0002] Hollow fiber membranes are widely used in membrane separation fields such as reverse osmosis, ultrafiltration, microfiltration, membrane contactors and membrane reactors. Common hollow fiber membrane materials include cellulose acetate, polyvinyl chloride, polypropylene, polyethylene, polyacrylonitrile, polysulfone, polyethersulfone, polyvinylidene fluoride, etc. Different applications put forward different requirements for hollow fiber membranes, including requirements for membrane pore size, porosity, mechanical properties, and corrosion resistance. [0003] PTFE has excellent properties such as strong acid and alkali resistance, oxidation resistance, microbial erosion resistance, and high and low temperature resistance. In addition to the excellent p...

AI Technical Summary

Problems solved by technology

[0007] U.S. Patent No. 4,496,507 provides a stretching device using slotted hot rollers. In this device, heating rollers are used for temperature control, and one hollow fiber is stretched at a time. During the stretching process, the hollow fiber is prone to breakage and hollow fiber collapse. And other issues

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