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US 4,927,579 AGranted
Method for making fiber-reinforced plastics
AssigneeThe Dow Chemical Company
InventorEugene R. Moore
Life of this patent
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Abstract
A method for adding intact fiber reinforcing material into thermoplastic resin compositions for toughening purposes without breakage of the fibers, including blending a polymeric solution and chopped fibers in a mixture at low to medium shear, injecting the resulting mixture into an extruder with a resin to be reinforced at an entry point positioned very near a vacuum point, and then removing the solvent for recycle while the reinforcing glass fiber and polymer blend is extruded.
Claims16
A method for reducing fiber breakage in preparing fiber reinforced plastic extrudate comprising:
- blending a low viscosity polymer solution having a total resin solids content in the range from 20 to 90 percent and a viscosity not greater than 50,000 centipoises and chopped fibers under low to moderate shear mixing conditions at a mixing speed in the range from 5 to 300 revolutions per minute and a temperature below the boiling point of the solvent of said polymer solution to form a dispersion of chopped fibers in said polymer solution, the dispersion having not more than 60 volume percent of reinforcing fiber;
- blending said dispersion into a molten polymer to be reinforced;
- and
- extruding the resultant blend while simultaneously removing the solvent therefrom to form a reinforced fiber plastic extrudate.
1 more element
Dependencies are inferred from the claim text.