Nova Chemicals (International) S.a.

Nova Chemicals Inc.

Douglas Checknita

P Scott Chisholm

Tony Tikuisis

Patrick Lam

Norman Dorien Joseph Aubee

Sarah Marshall

Denny Paul Sauvageau

Tingting Yu Chuang

XiaoChuan Wang

Norman Aubee

Shivendra K Goyal

Yves Lacombe

Mark Rejman

Matthew Zaki Botros

Renee Laurel Anseeuw

Derek Wasylenko

Nick K Bohnet

Fraser Waldie

John Leonard Bayley

John Bayley

Jared Taylor

Tingting Chuang

A polymer processing aid (PPA) reduces melt defects in extruded polyolefins in the absence of fluoropolymers. The polymer processing aid comprises a polyalkylene glycol such as a polyethylene glycol together with a high pressure low density polyethylene (LDPE) and reduces melt defects well in a thermoplastic polyolefin such as a linear low density polyethylene (LLDPE).

Fluoropolymer free polymer processing aids

In the manufacture of extruded polymers there are a number of surface defects referred to as sharkskin, snakeskin and orange peel which all generally relate to the rheology of the polymer melt. A severe form of surface defect is 'melt fracture' which is believed to result when the shear rate at the surface of the polymer is sufficiently high that the surface of the polymer begins to fracture. That is, there is a slippage of the surface of the extruded polymer relative to the body of the polymer melt. The surface generally can't flow fast enough to keep up with the body of the extrudate and a fracture in the melt occurs generally resulting in a severe loss of surface properties for the extrudate. A polymer extension process is disclosed wherein these undesirable surface defects are eliminated.

Polymer extrusion process

Barrier films are prepared from a blend of two high density polyethylene blend components and a high performance organic nucleating agent. The two high density polyethylene blend components have substantially different melt indices. Large reductions in the moisture vapor transmission rate of the film are observed in the presence of the nucleating agent when the melt indices of the two blend components have a ratio of greater than 10/1. The resulting barrier films are suitable for the preparation of packaging for dry foods such as crackers and breakfast cereals.

Barrier film for food packaging

Films suitable for shrink film applications are disclosed comprising at least one heterogeneous ethylene interpolymer having a short chain branching distribution profile index, DPI, that satisfies the formula: &#x2212;1&#x2266;DPI&#x2266;1. The at least one heterogeneous ethylene interpolymer has a density from about 0.911 g/cmto about 0.942 g/cm, a melt index from about 0.2 dg/min to about 3.5 dg/min and is produced using an in-line Ziegler-Natta catalyst. Additional embodiments include shrink films prepared from blends of at least one heterogeneous ethylene interpolymer and at least one high pressure ethylene polymer. The disclosed shrink films have improved puncture strength and machine direction shrink tunnel shrink force relative to control shrink films of the same composition but the control heterogeneous ethylene interpolymer, produced with a batch Ziegler-Natta catalyst, has a DPIgreater than 1.0.

Shrink films

A dual reactor solution polymerization process gives high density polyethylene compositions containing a first ethylene copolymer and a second ethylene copolymer and which have high dimensional stability, excellent processability as well as good organoleptic properties and reasonable stress cracking resistance. The polyethylene compositions are suitable for compression molding or injection molding applications and are useful, for example, in the manufacture of caps and closures for bottles, and for example, in bottles containing non-pressurized liquids.

Polyethylene compositions having high dimensional stability and excellent processability for caps and closures

The extrusion of thermoplastic polyolefin, especially linear low density polyethylene (LLDPE) is improved by the use of a processing additive comprising a blend of a thermoplastic acrylic polymer and a fluorocarbon polymer. In a preferred embodiment, the processing additive is a homogeneous blend of a thermoplastic styrene/methyl methacrylate polymer and a thermoplastic copolymer of vinylidene fluoride and hexafluoropropylene. The polyolefin extrudates produced according to this invention have reduced levels of melt fracture when extruded in conventional polymer extrusion equipment.

Melt fracture reduction

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Calgary, Canada

Douglas Checknita