Film bidirectional accurate stretching device

Abstract

The invention provides a film bidirectional accurate stretching device. The device comprises a first driving motor, a transverse stretching mechanism, a longitudinal stretching mechanism and a tensionsensor, wherein the transverse stretching mechanism and the longitudinal stretching mechanism are horizontally and vertically arranged, each of the transverse stretching mechanism and the longitudinal stretching mechanism comprises a strip-pressing stretching mechanism and a plurality of point-pressing stretching mechanisms, the point-pressing stretching mechanisms are in relative sliding connection with the strip-pressing stretching mechanisms, the strip-pressing stretching mechanism of the transverse stretching mechanism and the point-pressing stretching mechanisms of the longitudinal stretching mechanism correspond to each other at the same time to act, and the point-pressing stretching mechanisms of the transverse stretching mechanism and the strip-pressing stretching mechanism of thelongitudinal stretching mechanism correspond to each other at the same time to act. According to the device, in the single-direction stretching operation, the defects that a stretched film is wide intwo ends and narrow in middle are avoided, the overall shape of the stretched film is preliminarily ensured, the stretching effect is guaranteed, the tensile thin degree is uniform, and the defect that the stretching point is uneven in thickness due to fixed point stretching by adopting point-pressing fixation in the prior art is avoided.

Description

technical field [0001] The invention relates to stretching processing of polymer films, in particular to a film bidirectional precise stretching device. Background technique [0002] The final properties of polymer films strongly depend on processing methods and process conditions. The same polymer, different processing methods such as film blowing, casting, stretching, can produce films with different properties. Stretched films such as biaxially oriented polypropylene (BOPP) and polyester (BOPET) have the characteristics of high strength, strong light transmission, good air and moisture barrier properties, and excellent dimensional stability, so stretching has become the first choice for high-performance film processing. mainstream development direction. However, there are still big problems in the film stretching industry. For example, polyethylene (PE), the most important raw material for polymer films, has no mature biaxial stretching technology (BOPE) in the world. ...

AI Technical Summary

Problems solved by technology

[0003] Behind the industrial problem is actually the scientific problem of film stretching processing, which can be summarized as the following points: (1) In the prior art, "point pressure" is used to fix fixed-point stretching, so there is uneven thickness at the stretching point; (2) In the operation of unidirectional stretching, the stretched film is prone to deformation with wide ends and narrow middle; (3) Non-linear rheology of structural fluid in high-speed stretching; (4) Stretch flow induced Polymer conformational order and crystallization; (5) Crystal deformation, orientation and destruction in post-stretching

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