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Composition and Method of "B-Staging" Prepreg Laminate Materials Prior to Final Composite Structures

IP.com Disclosure Number: IPCOM000044005D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Appelt, BK: AUTHOR [+3]

Abstract

Current B-staging methods consist of applying an epoxy resin-hardener-solvent solution onto fiber glass cloth and allowing the solvent to evaporate, leaving a contiguous resin-hardener-fiber glass cloth mixture. "B-stage" (i.e., resin cure level, cross-link density, etc.) is controlled by carefully balancing the heat and time used to evaporate the solvent for each particular batch. Instances exist, however, where hardener settles out, improper B-stage levels are attained, resulting in improper resin flow during subsequent composite lamination, etc., and/or inadequate final composite cure is attained. This composition and method of "B-staging" prepreg laminate materials, prior to final composite structures, uses actinic radiation to attain a precisely controlled state of B-stage for prepreg.

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Composition and Method of "B-Staging" Prepreg Laminate Materials Prior to Final Composite Structures

Current B-staging methods consist of applying an epoxy resin-hardener-solvent solution onto fiber glass cloth and allowing the solvent to evaporate, leaving a contiguous resin-hardener-fiber glass cloth mixture. "B-stage" (i.e., resin cure level, cross-link density, etc.) is controlled by carefully balancing the heat and time used to evaporate the solvent for each particular batch. Instances exist, however, where hardener settles out, improper B-stage levels are attained, resulting in improper resin flow during subsequent composite lamination, etc., and/or inadequate final composite cure is attained. This composition and method of "B-staging" prepreg laminate materials, prior to final composite structures, uses actinic radiation to attain a precisely controlled state of B-stage for prepreg. Specifically the method for producing prepreg incorporates the process of partially acrylating an epoxy resin, adding a photosensitizer and an anhydride of a dicarboxylic acid or multifunctional amines, if so desired. The said resin mixture is then applied onto the reinforcing cloth and ultraviolet light is used to advance this coating to an adequate but accurately controlled state of B-stage cure. The photoreaction is designed such that, after B-staging, protective lighting is no longer required. In addition, the photoreaction serves to activate the thermal cure during subsequ...