Method For Producing Films Based On Plasticized Polyvinyl Acetal Having A Predefined Viscosity
AssigneeKuraray Europe GmbH
InventorsMichael HAERTH, Daniel WENZLIK
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Abstract
Plasiticized polyvinylacetal films with grater film-to-film uniformity are produced by a process of extruding a melt stream containing a polyvinyl acetal and a plasticizer at 150-250° C., the film having a predefined melt viscosity at 60-170° C., by providing a first melt stream of at least a first plasticizer and a first polyvinyl acetal resin and measuring its melt viscosity at 60-170° C. online; and adjusting the 60-170° C. melt viscosity by adding a second plasticizer and/or a second polyvinyl acetal resin to the first melt stream in an amount to provide a second melt stream with a melt viscosity at 60-170° C. having a difference of at most 20% to the predefined melt viscosity at 60-170° C.
Claims15
A process for extruding a melt stream comprising at least one polyvinyl acetal and at least one plasticizer having a predefined melt viscosity at 60-170° C. from an extruder at 150-250° C. comprising:
- a) providing a first melt stream comprising at least a first plasticizer and a first polyvinyl acetal resin and measuring its melt viscosity online at 60-170° C.;
- b) adjusting the melt viscosity of the first melt stream by adding a second plasticizer and/or a second polyvinyl acetal resin to the first melt stream in an amount to provide a second melt stream with a melt viscosity at 60-170° C. having a difference of at most 20% from the predefined melt viscosity at 60-170° C.
Dependencies are inferred from the claim text.