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US 5,965,072 AGranted
Molded aramid sheets
AssigneeE. I. Du Pont de Nemours and Company
InventorLee James Hesler
Life of this patent
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Abstract
Aramid sheet material and parts molded therefrom comprising m-aramid fibrids containing up to 10% by weight dyes that are thermally stable up to the glass transition temperature of the m-aramid polymer and p-aramid or m-aramid short fibers.
Claims5
A method to make aramid sheet material of various colors and molded parts therefrom comprising the steps of:
- (a) forming a solution of m-aramid polymer in a solvent;
- (b) extruding the mixture into a nonsolvent under shear conditions to form fibrids;
- (c) washing the fibrids in water to remove the solvent;
- (d) mixing the wet fibrids with water to dilute the fibrid concentration and adding a dye or pigment to the water fibrid mixture where in the dye or pigment is thermally stable up to or above the glass transition temperature of the m-aramid polymer;
- (e) heating the mixture from step (e) for a time sufficient for the fibrid to absorb dye or pigment and develop color;
- (f) mixing the colored fibrids with aramid fibers suitable for forming sheet material;
- (g) forming and drying the sheet material;
- and
- (h) forming a molded part from the sheet material by molding.
6 more elements
Dependencies are inferred from the claim text.