US 5,846,357 A · Method of making syntactic foam core material

Abstract

A syntactic structural foam product in flat sheet form or curved three-dimensional form adaptable to such uses as a light weight structural core for composite laminates, is made of a mixture of hollow ceramic microspheres and dry resin powder, of either thermosetting or a high-temperature thermoplastic resin, distributed in the interstices of the mass of microspheres for integration of the mixture into desired form upon heating and cooling. Resin powder collected as a waste by-product from resin coating materials can be recycled in the production of the desired product. The foam product is produced by first intermixing the microspheres and powdered resin by physical agitation of the mixture and depositing the mixture as a layer over a surface having a release agent thereover within a dimension defining region between boundary members and then supplying heat with or without pressure to the layer at a temperature and for a time period sufficient to effect a melting of the resin powder and thereafter cooling the resin in a hardened condition to integrate the mixture into the product desired after which the product is withdrawn from the forming zone. Reinforcing elements such as glass or carbon fibers can be selectively included in the mixture for predeterminable desired physical and mechanical properties.

Claims20

Dependent claims

A method of forming a syntactic foam layer adaptable to use in composite products comprising

intermixing a mass of hollow ceramic microspheres and an interbonding resin in dry powdered form thereby forming a mixture of microspheres and resin,
wherein said resin in dry powdered form consists of particles which are substantially finer than said microspheres,
said microspheres being at least 60% of the volume of said mixture,
physically agitating said mixture to establish a uniformity of distribution of the resin powder throughout the mass of microspheres,
depositing said uniform mixture as a layer over a base surface having a layer of separator material thereover,
processing the layer of said mixture through a cycle of heating to melt said resin powder and setting said melted resin to fuse the resin and microspheres into a rigid integrated layer,
the amount of dry resin powder intermixed with the microspheres being an amount which is effective to interbond the resin and microspheres and form void spaces in the layer.

4 more elements

Dependencies are inferred from the claim text.

Method of making syntactic foam core material

Life of this patent

Method of making syntactic foam core material

Life of this patent

Abstract

Claims20