Bp Chemicals Limited

Brian Leslie Turtle

Christopher James Frye

Frederic Alarcon

David George Gilbert

Novel stretch and blown films are prepared based on copolymers of ethylene and alpha-olefins having (a) a density in the range 0.900 to 0.940 (b) an apparent Mw/Mn of 2&#x2013;3.4 (c) I/Ifrom 16 to 24 (d) activation energy of flow from 28 to 45 kJ/mol (e) a ratio Ea(HMW)/Ea(LMW)&#x3e;1.1, and (f) a ratio g'(HMW)/g&#x2032;(LMW) from 0.85 to 0.95. The films exhibit an excellent combination of strength and processability and are particularly suitable for use as either stretch films or blown films for use as heavy duty sacks. The preferred films show a dart impact of &#x3e;1100 g and MD elongations of &#x3e;500%.

Polyethylene films

A blend having improved optical and good mechanical properties comprising (A) at least 75 weight %, preferably 85-95 weight %, of ethylene hydrocarbon copolymer (LLDPE) of density 0.916 to 0.930 manufactured by the transition metal catalyzed gas-fluidized bed process and (B) not less than 1 weight %, of low density polyethylene or ethylene copolymer made by the free radical catalyzed high pressure process. The LLDPE (A) is preferably ethylene/butene-1 or ethylene/hexene-1 copolymer. The high pressure polymer (B) is preferably an autoclave LDPE having a high die swell ratio and a MIR below 50.

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Oxshott, United Kingdom

Brian Leslie Turtle