Flat dies for calendered film extrusion

Abstract

A flat opening mold used for extruding of a calendering film comprises an extruding barrel connected with a pushing press; the outlet end of the extruding barrel is connected with the inlet end of a transition connector; the outlet end of the transition connector is connected with the inlet end of a forming mold in a flat shape; the transition connector is provided with a first inner cavity gradually shrunk from the inlet end of the transition connector to the outlet end of the transition connector; the inlet end of the forming molding is provided with a second inner cavity gradually shrunk inwards; the outlet end of the second inner cavity is connected with an extension cavity; and the area of the section of the extension cavity in the flowing direction of a blank is in the gradient change that the area of the section is progressively increased, constant and progressively decreased in sequence. The flat opening mold has the following beneficial effects that by means of design of a mold cavity, the mold blank can be formed at a time, the breadth width is uniform, the mold blank thickness uniformity is high, and the longitudinal and transverse stretching strength consistency is good.

Description

technical field [0001] The invention belongs to the field of thermoplastic material processing, and in particular relates to a flat mouth die used for calendering film extrusion. Background technique [0002] PTFE, that is, polytetrafluoroethylene material, is more and more widely used in industrial production and the rising environmental protection industry. It was first used for the sealing of industrial and residential water supply and air supply pipelines, and the packing of filter devices. Now The production of equipment in the medical field such as artificial joints, artificial blood vessels, various filter devices in the field of environmental protection, and the production of waterproof and breathable clothing in the field of daily life have also been further expanded. [0003] The pre-processing of the above products is inseparable from the production of PTFE membrane blanks. The traditional production method of PTFE membrane blanks is to pre-extrude a round bar of ...

AI Technical Summary

Problems solved by technology

In this process, the friction of each interface between a pair of calender rolls and the PTFE prefabricated bar is different from each other. Sometimes the friction force of the upper calender roll is large, and sometimes the friction force of the lower calender roll is large, so that the transverse tensile strength of the obtained film blank is different. It is more rigid, which leads to irregular edges and poor surface quality, and there are disadvantages such as subsequent dimensioning, machining, and width cutting.

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