Expandable films and molded products therefrom
AssigneeThe Dexter Corporation
InventorRaymond S. Wong
Life of this patent
Estimating the term…
Abstract
A thin, tacky, non-pourable film of incompatible in situ-expandable thermoplastic particles and thermosettable matrix resin that contains an essentially uniform density and thickness across the breadth of the film. The in situ-expandable mass is not pourable yet can be easily dispensed in a uniform manner within a mold and thereafter expanded to the dimensions of the mold. Composites and reinforced compositions, as well as methods of molding, are disclosed.
Claims25
A thin and drapable, non-pourable, in situ-expandible film having a uniform thickness of .+-.10% variation, of up to about 3.5 millimeters, that contains (i) a non-pourable thermosetting matrix resin system and (ii) particles of a microcellular in situ-expandable thermoplastic polymer containing an expansion agent therein in which both (i) and (ii) are uniformly distributed throughout the film, so that upon expansion of the thermoplastic polymer into microcells in the non-pourable film, the resulting film is a molded thermoset thin film syntactic foam the thickness of which is about 1.01 to about 4 times greater than the non-expanded film.
A thin and drapable, non-pourable film suitable for forming, on molding, a syntactic foam thermoset article, that contains across its breadth (i) an essentially uniform thickness of .+-.10%, (ii) an essentially uniform density, (iii) a uniform mixture of (1) in situ-expandable thermoplastic particles having a mixed particle size having different expandabilities ranging from about 1 .mu.m to about 1 mm and (2) a thermosettable matrix resin in which (1) and (2) are incompatible throughout the thermal expansion cycle in forming the syntactic foam thermoset article, said film possessing a predetermined shape and thickness of up to 3.5 millimeters, for converting it to the syntactic foam thermoset article in which the film
- a. expands up to 4 times in thickness to the dimensions of the thermoset article,
- b. without major redistribution of the mass within the film,
- c. to form a syntactic foam thermoset article having a predetermined density pattern.
Dependencies are inferred from the claim text.