Foamed liquid crystal polymer film/sheet having improved flexibility and cell uniformity
AssigneeHoechst Celanese Corporation
InventorsRandy D. Jester, Detlef K. M. Frank
Life of this patent
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Abstract
A flexible foamed liquid crystal polymer film or sheet having uniformly small cells or bubbles. The foam cells are essentially spherical and have mean diameters less than or equal to approximately 250 microns. The cell size distribution is relatively small. The foamed sheet is made by extruding the polymer through a die under pressure at a temperature near or below the polymer's melting point; a gas or chemical blowing agent is extruded with the polymer to produce foaming as the polymer exits the die.
Claims14
A flexible liquid crystal polymer foam comprising foam cells wherein substantially all of said cells do not exceed 250 microns in diameter and said cells have a cell diameter distribution such that substantially all of said cell diameters are within about 20% of the average cell diameter.
A flexible liquid crystal polymer foam comprising foam cells, wherein substantially all of said cells do not exceed 250 microns in diameter and said cells have a cell diameter distribution such that substantially all of said cell diameters are within about 20of the average cell diameter, made according to a process comprising:
- melting a liquid crystal polymer;
- combining said liquid crystal polymer with a gas or chemical blowing agent to form an extrudable composition;
- and,
- forcing said composition through an extrusion die under pressure while maintaining said composition near or below the melting point of said polymer, said composition forming said liquid crystal polymer foam as it exits said die.
Dependencies are inferred from the claim text.