Exxonmobil Chemical Patents Inc.

Bart Lauwers

Stefan B Ohlsson

Jan Cyriel Donck

Jef Vaes

The invention relates to a polymer comprising units derived from ethylene having: a) a Melt Index of from 0.05 to 20 g/10 min; b) at least 10 per 1000 C-atoms of short chain branches, containing five carbon atoms or less, and less than 3.5 mol %, of units derived from a copolymerizable ethylenically unsaturated ester, c) a density of from 0.90 to 0.94 g/cm, preferably 0.91 to 0.935 g/cm, especially 0.92 to 0.93 g/cm, and d) a relaxation time as described herein of at least 10 s. The polymer may be used for stretch hood film, preferably as a blown film coextruded tube comprising: a) a core of the above polymer; and b) a skin layer, on each side of the core which may be of the same or different composition, comprising at least 60 wt % of an LLDPE having density of 0.91 to 0.94 g/cm.

Polymers of ethylene and, optionally, copolymerizable esters, films using such polymers and stretch hood packaging processes using such films

Polymers comprising units derived from ethylene, said polymer having: a) a Melt Index of from 0.05 to 20 g/10 min. as determined by ASTM-1238 Condition E; b) at least 10 per 1000 C-atoms of short chain branches, containing five carbon atoms or less, as determined by C13 NMR, and less than 3.5 mol %, of units derived from a copolymerizable ethylenically unsaturated ester; c) a density of from 0.90 to 0.94 g/cm, preferably 0.91 to 0.935 g/cm, especially 0.92 to 0.93 g/cmas determined by ASTM D1505; and d) a relaxation time as described herein of at least 10 s. Such polymers can be obtained by free radical polymerization using a chain transfer agent that incorporates into the polymer chain such as an alpha-olefin, preferably propylene, as a chain transfer agent, preferably in a tubular reactor under circumstances to favor LCB formation in a down stream part of the tubular reactor.

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Schriek, Belgium

Bart Lauwers