Method of making plastic foam laminates

Claim 1

A METHOD OF MAKING A LAMINATED ARTICLE HAVING A LAYER OF VINYL CHLORIDE RESIN FOAM ATTACHED TO A SHEET OF BASE MATERIAL COMPRISING MILLING A SOLID VINYL CHLORIDE RESIN HAVING A FUSION TEMPERATURE OF 150*C. TO 185*C. AND A BLOWING AGENT HAVING A DECOMPOSITION TEMPERATURE OF AT LEAST 190*C., THE RESULTING MILLED MIXTURE BEING A UNITARY, SOLID, NON-PARTICULATE MASS WHICH IS NON-FLOWABLE AND SELF-SUPPORTING AT ROOM TEMPERATURE, CALENDERING THE SAID MASS CONTINUOUSLY INTO A THIN, COHERENT FILM OF INDEFINITE LENGHT HAVING A THICKNESS OF FROM 0.001 TO 0.15 INCH, THE TEMPERATURE DURING SAID CALENDERING BEING WITHIN THE RANGE OF 150*C. TO 185%C. AND BEING SUFFICIENT TO FUSE THE RESIN SO THAT THE FILM THUS PRODUCED IS STRONG AND INHERENTLY CAPABLE OF BEING REHEATED BRIEFLY IN EXCESS OF FUSION TEMPERATURE WITHOUT ENCOUNTERING A NON-STRENGTH CONDITION, THE SAID FILM BEING APPLIED TO A SHEET OF BASE MATERIAL, SUBSEQUENTLY PASSING A RUNNING LENGTH OF THE RESULTING ASSEMBLY OF FILM AND SHEET OF BASE MATERIAL CONTINUOUSLY THROUGH AN OVEN WHEREIN THE ASSEMBLY IS HEATED TO A FILM TEMPERATURE OF 190*C. TO 225*C. AT ATMOSPHERIC PRESSURE WITHOUT CONFINEMENT, SAID FILM TEMPERATURE BEING MAINTAINED FOR A PERIOD OF 5 TO 60 SECONDS TO DECOMPOSE THE BLOWING AGENT WITH LIBERATION OF GAS AND FREELY EXPAND THE FILM WITHOUT DISRUPTION TO FORM A UNIFORM, BLOWN SHEET HAVING AT LEAST SEVERAL TIMES THE THICKNESS OF THE ORIGINAL FILM, SUCH BLOWN SHEET HAVING A CONTINUOUS SURFACE AND BEING ATTACHED TO SAID BASE, AND IMMEDIATELY THEREAFTER COOLING THE ASSEMBLY.

Claim 2

A METHOD OF MAKING A LAMINATED ARTICLE HAVING A LAYER OF VINYL CHLORIDE RESIN FOAM ATTACHED TO A SHEET OF BASE MATERIAL COMPRISING MILLING A SOLID VINYL CHLORIDE RESIN HAVING A FUSION TEMPERATURE OF 150*C. TO 185*C. AND A BLOWING AGENT HAVING A DECOMPOSITION TEMPERATURE OF AT LEAST 190*C., THE RESULTING MILLED MIXTURE BEING A UNITARY, SOLID, NON-PARTICULATE MASS WHICH IS NON-FLOWABLE AND SELF-SUPPORTING AT ROOM TEMPERATURE, CALENDERING THE SAID MASS CONTINUOUSLY INTO A THIN, COHERENT FILM OF INDEFINITE LENGHT HAVING A THICKNESS OF FROM 0.001 TO 0.15 INCH, THE TEMPERATURE DURING SAID CALENDERING BEING WITHIN THE RANGE OF 150*C. TO 185%C. AND BEING SUFFICIENT TO FUSE THE RESIN SO THAT THE FILM THUS PRODUCED IS STRONG AND INHERENTLY CAPABLE OF BEING REHEATED BRIEFLY IN EXCESS OF FUSION TEMPERATURE WITHOUT ENCOUNTERING A NON-STRENGTH CONDITION, THE SAID FILM BEING APPLIED TO A SHEET OF BASE MATERIAL, SUBSEQUENTLY PASSING A RUNNING LENGTH OF THE RESULTING ASSEMBLY OF FILM AND SHEET OF BASE MATERIAL CONTINUOUSLY THROUGH AN OVEN WHEREIN THE ASSEMBLY IS HEATED TO A FILM TEMPERATURE OF 190*C. TO 225*C. AT ATMOSPHERIC PRESSURE WITHOUT CONFINEMENT, SAID FILM TEMPERATURE BEING MAINTAINED FOR A PERIOD OF 5 TO 60 SECONDS TO DECOMPOSE THE BLOWING AGENT WITH LIBERATION OF GAS AND FREELY EXPAND THE FILM WITHOUT DISRUPTION TO FORM A UNIFORM, BLOWN SHEET HAVING AT LEAST SEVERAL TIMES THE THICKNESS OF THE ORIGINAL FILM, SUCH BLOWN SHEET HAVING A CONTINUOUS SURFACE AND BEING ATTACHED TO SAID BASE, AND IMMEDIATELY THEREAFTER COOLING THE ASSEMBLY.