Process for the treatment of linear low density polyethylene by organic peroxides which generate free radicals
AssigneeBP Chimie
InventorsJean-Paul Thiersault, Alain Senez, Jean L. Vidal
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Abstract
The invention relates to a process of thermomechanical treatment in the molten state, in the presence of organic peroxides, of co-polymers with a density less than 0.935, obtained by co-polymerization under a pressure of less than 4 MP.sub.a of ethylene and a higher alpha-olefin. The co-polymers thus treated may advantageously be used for the manufacture of finished objects such as films according to the current techniques of conversion of "high pressure" type polyethylene.
Claims8
A process for treating co-polymers of linear low density polyethylene having a density of less than 0.935, a fluidity index at 190.degree. C. under 2.16 kg as per NFT 51016 standard, Method A, of between 0.3 and 50, and a branching index greater than 0.95, in which the co-polymer is obtained by copolymerization under a pressure less than 4 MP.sub.a, of a mixture of ethylene and a higher alpha-olefin containing 4 to 20 percent by weight of the higher alpha-olefin, comprising treating the co-polymer thermomechanically in the molten state at a temperature less than 220.degree. C., in the presence of an organic peroxide which produces free radicals, in which the organic peroxide is employed in an amount within the range of 0.005% to 1% by weight of the co-polymer, such that the treated co-polymer has a branching index within the range of 0.8 to 0.95 and its gelling rate, as measured by extraction with boiling xylene, is zero.
Dependencies are inferred from the claim text.