Prestressed article
AssigneeThe United States of America as represented by the Secretary of the Army
InventorsIrving E. Figge, Edward H. Dean
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Abstract
Thermoforming, utilized for making articles from sheets of thermoplastic ins, does not readily yield articles having desired strength properties. Using both thermoplastic and thermosetting resins in the process results in articles embodying fabrication stresses akin to those in prestressed concrete.
Claims1
A thermoformed article in the form of a three dimensionally curved surface embodying laminae of alternate epoxy resin layers fused to thermoplastic resin layers, each epoxy resin layer being an epoxy resin-impregnated high tensile strength fiberous weft, each thermoplastic resin layer being an acrylonitrile polymer, the epoxy resin layers being pretensiled by stresses developed during thermoforming.
Dependencies are inferred from the claim text.