Method for preparing thick polyvinyl butyral (PVB) film by direct water cooling process

Abstract

The invention belongs to the technical field of plastic molding and processing, in particular to a method for preparing a thick polyvinyl butyral (PVB) film by a direct water cooling process. The method comprises the following specific steps: (1) mixing materials; (2) extruding and plasticizing; (3) shaping by the direct water cooling process; (4) removing surface water; (5) performing online thickness measurement; and (6) drying, splitting and winding. In the invention, the PVB film with the thickness of more than 1mm is produced by combining the direct water cooling process with a drying treatment method, which can greatly reduce the time that a fused mixture of the PVB and a plasticizer is exposed to air, realize rapid cooling, high cooling efficiency and even thickness, and avoid the defects such as material aging and yellowing, reduced mechanical properties, shortened service life, high production cost and the like.

Description

Technical field: [0001] The invention belongs to the technical field of plastic molding processing, and particularly relates to a method for preparing thick polyvinyl butyral film by direct cooling with water. Background technique: [0002] Direct water cooling is very common in the processing of plastic pellets, plates, and profiles, but it is rare to apply direct water cooling to sheets or plastic films. Only the patent is disclosed: CN101177040A uses water for direct cooling. For blown film, it is used to solve the problem of uneven thickness of film embryo and insufficient cooling. [0003] Polyvinyl butyral (PVB) has very good transparency, mechanical strength, cold resistance, ultraviolet resistance, and good adhesion to glass. It is the most widely used intermediate layer material in the field of laminated glass. The mixture of molten polyvinyl butyral and plasticizer is prone to oxidation and chain scission when exposed to the air, which causes the material to change color...

AI Technical Summary

Problems solved by technology

The mixture of polyvinyl butyral and plasticizer in the molten state is prone to oxidation and chain scission when exposed to the air, which will cause the material to change color and yellow, reduce the mechanical properties and shorten the service life

[0004] At present, the production process of PVB film is that polyvinyl butyral and plasticizer are mixed by extruder, then shaped by die head, and then indirectly cooled and shaped by embossing roller and cooling roller. This process has the following disadvantages Advantages: First, because the film is exposed to the air for a long time at high temperature, the material is easy to age and turn yellow; second, due to indirect cooling, the cooling efficiency is not high, and it is difficult to produce a film with a thickness greater than 1mm; third, the embossing rod and cooling The equipment investment of the roller is relatively large, which increases the cost of production

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