Glass/polyvinylbutyral laminates having directional surface patterns and a process for preparing same
AssigneeE.I. du Pont de Nemours and Company
InventorsChul Won Choi, Sang Gyu Lee
Life of this patent
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Abstract
De-airing of PVB/glass laminates can be improved, while haze in the pre-press is minimized and sleep time reduced as a result using a PVB sheet having a roughened surface with directionality. A roughened surface with a washboard pattern that is useful in this regard can be obtained by varying certain conditions of a melt-fracture extrusion process.
Claims6
A process for creating a directional pattern on a surface of a polyvinyl butyral sheet comprising the step of extruding molten polyvinyl butyral using a melt fracture extrusion process, wherein the pattern can be controlled by varying extruder die pressure and wherein an embossing tool is not used, characterized in that the directional pattern is a herringbone pattern that is created using a die pressure of from 29.2 to 36.0 kg/cm2.
A process for producing a laminate comprising the steps of
- A. forming a polyvinyl butyral sheet having a directional surface pattern by extruding molten polyvinyl butyral using a melt fracture extrusion process, wherein the pattern can be varied by varying extruder die pressure and wherein an embossing tool is not used, characterized in that the directional pattern is a herringbone pattern created using a die pressure of from 29.2 to 36.0 kq/cm2;
- and
- B. forming a layered assembly comprising said polyvinyl butyral sheet by contacting said polyvinyl butyral sheet with at least one layer of glass;
- C. forming a pre-press by heating and de-airing said layered assembly under vacuum;
- and
- D. heating said pre-press in an autoclave while applying heat and pressure to bond said polyvinyl butyral sheet and said at least one glass layer, thereby forming a laminate.
Dependencies are inferred from the claim text.