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US 4,228,255 AGranted
Method for producing crosslinked polyethylenes
AssigneeThe Fujikura Cable Works, Ltd.
InventorsIkuo Fujimoto, Setsuya Isshiki, Yoshikazu Kurita, Yoji Sato
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AssigneeThe Fujikura Cable Works, Ltd.
InventorsIkuo Fujimoto, Setsuya Isshiki, Yoshikazu Kurita, Yoji Sato
Estimating the term…
A novel method for crosslinking a polyolefin comprising reacting a polyolefin, which is a low density polyethylene having a density less than 0.93 and melt index of 0.1-0.5 g/10 min. or a polyolefin mixture containing a low density polyethylene having a density less than 0.93 as major component, with an organic silane and a free radical generating compound to form a silane-grafted polyolefin, then mixing silane-grafted polyolefin with a silanol condensation catalyst, and heating them. According to this method, the crosslinking takes place concurrently with forming by extrusion, and a shaped article having a high degree of crosslinking with smooth surface is obtained. The method according to this invention is especially suited for covering electrical wires with polyolefin.
A method for producing a crosslinked polyolefin comprising reacting a polyolefin which is a low density polyethylene having a density less than 0.93 and a melt index of 0.1 to 0.5 g/10 min. or a polyolefin mixture containing a low density polyethylene having a density less than 0.93 as major component, with a free radical generating compound and an organic silane having the general formula RR'SiY.sub.2, wherein R represents a monovalent olefinically unsaturated hydrocarbon or hydrocarbonoxy radical, each Y represents a hydrolyzable organic radical, and R' represents a monovalent hydrocarbon radical with the exception of aliphatically unsaturated hydrocarbon radicals, or a Y radical, to form a silane-grafted polyolefin, then mixing said silane-grafted polyolefin with a silanol condensation catalyst, and heating the mixture in the absence of water.
A method for producing a crosslinked polyolefin comprising reacting a polyolefin which is a low density polyethylene having a density less than 0.93 and a melt index of 0.1 to 0.5 g/10 min., or a polyolefin mixture having a melt index of 0.1 to 0.5 g/10 min. and consisting of a low density polyethylene having a density less than 0.93, polyproplyene or a high density polyethylene in an amount of not more than 15% by weight based on the total weight of the polyolefin mixture, with a free radical generating compound and an organic silane having the general formula RR'SiY.sub.2, wherein R represents a monovalent olefinically unsaturated hydrocarbon or hydrocarbonoxy radical, each Y represents a hydrolyzable organic radical, and R' represents a monovalent hydrocarbon radical except aliphatically unsaturated hydrocarbon radicals, or a Y radical, to form a silane-grafted polyolefin, then mixing said silane-grafted polyolefin with a silanol condensation catalyst, and heating the mixture in the absence of water.
A method for producing a crosslinked polyethylene comprising reacting a polyethylene mixture consisting of a low density polyethylene having a density less than 0.93 in an amount of 50 to 99% by weight and a high density polyethylene having a density not less than 0.93 in an amount of 50 to 1% by weight, with a free radical generating compound and an organic silane having the general formula RR'SiY.sub.2, wherein R represents a monovalent olefinically unsaturated hydrocarbon or hydrocarbonoxy radical, each Y represents a hydrolyzable organic radical, and R' represents a monovalent hydrocarbon radical with the exception of aliphatically unsaturated hydrocarbon radicals, or a Y radical, to form a silane-grafted polyethylene, then mixing said silane-grafted polyethylene with a silanol condensation catalyst, and heating in the absence of water.
Dependencies are inferred from the claim text.