Thermoplastic foam molding

Claim 3

The process of claim 1 wherein said polymer is a member selected from the group consisting of a solvent imbibable polyetherimide, polycarbonate and polymer blend of polyphenylene oxide and polystyrene.

Claim 4

The process of claim 2 wherein the solvent is a member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof.

Claim 5

The process of claim 3 wherein said polyetherimide is a polymer of the following chemical structure: ##STR3## wherein n is a positive integer, Ar is a divalent radical containing from 6-20 carbon atoms, R is a bivalent radical selected from the group consisting of aliphatic, cycloaliphatic, aromatic and araliphatic groups.

Claim 6

The process of claim 4 wherein said solvent is present in said particles in up to 30 parts per 100 parts by weight of said resin.

Claim 7

The process of claim 5 wherein said blowing agent is present in from 0.5 to 20 parts per 100 parts by weight of said resin.

Claim 8

The process of claim 1 wherein said mold is pressurized to from about 300-1500 p.s.i. with a gaseous system comprising an inert gas.

Claim 9

The process of claim 7 wherein said gaseous system comprises a mixture of an inert gas and a particle pressure of separately added solvent in vapor form.

Claim 10

The process for preparing a molded polyetherimide polymer foam structure comprising: (a) impregnating a polyetherimide polymer in particle form with a solvent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof, in an amount sufficient to foam said polymer to a density less than about 20 lbs/ft 3 , to yield at a substantially free flowable particulate combination; (b) partially filling a mold with said free flowable particulate combination; (c) pressurizing said mold to prevent any substantial vaporization of said solvent member during subsequent polymer melting; (d) heating said polymer to a flowable state; (e) releasing the mold pressure to permit foaming of the melt and expansion of the foamed polymer within the mold; and (f) removing the molded foam structure from the mold.

Claim 11

The process for preparing a molded polyetherimide polymer foam structure comprising: (a) impregnating a polyetherimide polymer in particle form with a solvent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof, in an amount sufficient to foam said polymer to a density less than about 20 lbs/ft 3 , to yield at a substantially free flowable particulate combination; (b) partially filling a mold with said free flowable particulate combination; (c) pressurizing said mold to prevent any substantial vaporization of said solvent member during subsequent polymer melting; (d) heating said polymer to a flowable state; (e) releasing the mold pressure to permit foaming of the melt and expansion of the foamed polymer within the mold; and (f) removing the molded foam structure from the mold.

Claim 12

The process of claim 9 wherein said polyetherimide is a polymer of the following chemical structure: ##STR4## wherein n is a positive integer, Ar is a divalent radical containing from 6-20 carbon atoms, R is a bivalent radical selected from the group consisting of aliphatic, cycloaliphatic, aromatic and araliphatic groups.

Claim 13

The method of claim 9 wherein the precursor of Ar is Bisphenol A and R is phenylene.

Claim 14

The process of claim 11 wherein said mold is pressurized to from about 300-1500 p.s.i. with a gaseous system comprising an inert gas.

Claim 15

The process of claim 12 wherein said gaseous system comprises a mixture of an inert gas and a partial pressure of separately added solvent in vapor form.

Claim 16

The process of claim 13 wherein said pressure and gaseous system is such as to at least substantially maintain the originally imbibed solvent member in said resin until pressure release.