Skinning process for expansion casting of polymeric foams

Claim 2

A PROCESS FOR EXPANSION CASTING A POLYMERIC FOAM OBJECT HAVING A SKINNED SMOOTH SURFACE WHICH COMPRISES: PLACING A HIGHLY GAS PERMEABLE MEMBERANE SHEET ON THE SURFACE OF A MOLD CAVITY; PLACING AN ABS THERMOPLASTIC FOAM MATERIAL INTO THE MOLD UNTIL THE MOLD IS FILLED, SAID FOAM MATERIAL CONTAINING A HEAT-SENSITIVE, CHEMICAL BLOWING AGENT WHICH WHEN EXPOSED TO HEAT EMITS AN INERT GAS WHICH CAUSES SAID MATERIAL TO EXPAND TO THE CONTOUR OF THE MOLD CAVITY; AND HEATING SAID MOLD TO A TEMPERATURE SUFFICIENT TO ACTIVATE SAID BLOWING AGENT GAS AND CAUSE EXPANSION OF SAID MATERIAL, THE BLOWING AGENT GAS AND ANY AIR IN SAID CAVITY PERMEATING THROUGH SAID SHEET TO PRODUCE A SMOOTH SKIN ON THE SURFACE OF THE FOAM MATERIAL ADJACENT THE SHEET WITH NO ADHERENCE BETWEEN SAID SHEET AND THE FOAM MATERIAL.

Claim 3

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.001-0.002 inch thick silicone treated, clay coated kraft release paper on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface on the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 4

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.001-0.002 inch thick silicone treated, clay coated kraft release paper on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface on the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 5

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.002-0.010 inch thick fluorinated ethylene propylene on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface of the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 6

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.002-0.010 inch thick fluorinated ethylene propylene on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface of the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 7

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.030-0.060 inch thick siLicone rubber on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface on the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 8

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.030-0.060 inch thick siLicone rubber on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface on the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 9

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.005-0.016 inch thick silicone rubber coated glass fabric on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface of the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 10

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.005-0.016 inch thick silicone rubber coated glass fabric on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface of the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 11

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.003-0.015 inch thick flourocarbon film coated fiberglass on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface of the foam material adjacent the sheet with no adherence between said sheet and the foam material.

Claim 12

A process for expansion casting a polymeric foam object having a skinned smooth surface which comprises: placing a highly gas permeable sheet of from 0.003-0.015 inch thick flourocarbon film coated fiberglass on the surface of a mold cavity; placing an ABS thermoplastic foam material into the mold until the mold is filled, said foam material containing a heat-sensitive, chemical blowing agent which when exposed to heat emits an inert gas which causes said material to expand to the contour of the mold cavity; and heating said mold to a temperature sufficient to activate said blowing agent and cause expansion of said material, the blowing agent gas and any air in said cavity permeating through said sheet to produce a smooth skin on the surface of the foam material adjacent the sheet with no adherence between said sheet and the foam material.