KR830004957A - Process for producing crosslinked polyolefin continuous foam - Google Patents

Abstract

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Description

Process for producing crosslinked polyolefin continuous foam

Since this is an open matter, no full text was included.

1A is also a graph of a crosslinking curve and a decomposition curve of an organic blowing agent obtained by an operation according to the method of the present invention. 1B is also a graph of the crosslinking and decomposition curves of organic foaming agents obtained by crosslinking and foaming operations using organic peroxides according to a conventional method, and 1C also by crosslinking and foaming operations using electron beams according to the conventional method. Graph of bridging and decomposition curves. 2-6 is a graph showing that the pattern viscosity for the composition used in the present invention changes over time. 7 is a graph showing the crosslinking ratio according to the amount of crosslinking agent added.

Claims (12)

The crosslinking rate, expressed as a gradient of the viscosity curve measured on a Mooneystometer at a foaming temperature suitable for uniformly foaming the composition of the polyolefin with the degradable organic blowing agent, exceeds 6.8 kg-cm / min (from 0 to 5 minutes). Operation of adding the crosslinking agent in an amount which does not occur, operation of kneading the resulting mixture, operation of molding the foamable composition into a desired shape so as not to cause decomposition of the foaming agent in the resultant foamable composition, and pressing the molded foamable composition under atmospheric pressure or at the foaming temperature. A process for producing a crosslinked polyolefin continuous foam, comprising the steps of heating in a heating medium to obtain a foam having a thin film of foam and subjecting the foam to mechanical foam to break the foam films. The method according to claim 1, wherein the foaming temperature is from 145 ° to 210 ° C. Method according to claim 2 characterized in that the foaming temperature is 160 ° to 190 ° C. Method according to claims 1, 2 or 3, characterized in that the heating medium is a metal bed or molten salt bath. The method according to claim 1, wherein molding of the foamable composition is performed by increasing the pressure at elevated temperature. Method according to claim 5, characterized in that the molding temperature is in the range of 125 to 160 ° C lower than the foaming temperature. Method according to claim 6, characterized in that the molding temperature is 130 to 140 ℃. The process according to claim 1, wherein the molding operation of the foam composition is carried out by an extruder or a calender roll. Method according to claim 1, characterized in that the mechanical deformation operation is carried out by a compression force between two rolls rotating at the same speed. Polyolefins are ethylene-vinyl acetate copolymers; Ethylene-propylene copolymers; Ethylene-propylene-diene copolymers; Copolymers of ethylene with up to 45% acrylic or methacrylic acid-methyl, -ethyl, -propyl and butyl and high density polyethylene, medium density polyethylene, low density polyethylene, chlorinated polyethylene or polypropylene with one or more of the aforementioned copolymers Method according to claim 1, characterized in that it is selected from mixtures with. The method of claim 1 wherein the crosslinker is an organic peroxide having a decomposition temperature above the pour point of polyethylene. The method according to claim 1, wherein the decomposable organic blowing agent is selected from an azo compound, a nitroso-based compound, a hydrazide-based compound, and a sulfonyl semicarbazide-based compound having a decomposition temperature above the melting point of the polyolefin. ※ Note: The disclosure is based on the initial application.