Importance

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Abstract

A method and apparatus for molding foamed materials for use as carpet underpadding is disclosed. In one aspect, the process and apparatus involves pulling a sheet of a foamed material through a first set of pull rolls at a first pull rate followed by heating the foamed material in order to decompose blowing agent present in the sheet thereby causing the sheet to expand or thicken. The heated sheet is then pulled through a second set of pull rolls which pull the heated sheet at a faster rate than the first pull rate in order to stretch the expanded sheet so that it returns to its original thickness. The surface of one of the rolls of the second set is provided with dimples or indentations uniformly spread on the surface thereof for producing protrusions on one side of the heated sheet. In one form of the apparatus, the roller with the dimples is cooled while the molded sheet is retained against this roller after formation of the dimples in order to provide cooling for the former to allow the protrusions to set properly. The molded sheet is further cooled as it is run along cooled rolls after which it is trimmed and collected.

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First Claim