Du Pont of Canada Limited

E.i. Dupont De Nemours and Company

Dupont Canada Inc.

Peter J Lovell

Ian C Saunders

A helmet for the protection of sportsmen and/or workers in potentially hazardous occupations is disclosed. In one embodiment the helmet comprises a protective head shell and means to position the helmet on a users head in which the head shell has an outer section slidably connected to an inner section. The outer section is adapted to move relative to the inner section on impact with an object. In another embodiment the helmet further comprises a plurality of cushioning projections located between the two shells, each projection being integrally connected to one of the shells.

Protective helmet

An ethylene polymer having a density in the range of about 0.940-0.960, a melt index in the range 100-200 and a ratio of weight-average molecular weight to number-average molecular weight of less than 5 is disclosed. The polymer is a copolymer of ethylene and at least one .alpha.-olefin having 4-10 carbon atoms, e.g., butene-1, hexene-1 or octene-1. The preferred polymer is a copolymer of ethylene and butene-1. The polymers may be used in the injection moulding of thin-wall containers, e.g., containers having a wall thickness of less than 0.7 mm, especially a thickness of less than 0.5 mm and in particular a thickness of less than 0.4 mm.

Ethylene polymers of high melt index

An ethylene polymer having a density in the range of about 0.940-0.960, a melt index in the range 100-200 and a ratio of weight-average molecular weight to number-average molecular weight of less than 5 is disclosed. The polymer is a copolymer of ethylene and at least one .alpha.-olefin having 4-10 carbon atoms e.g. butene-1, hexene-1 or octene-1. The preferred polymer is a copolymer of ethylene and butene-1. The polymers may be used in the injection molding of thin-wall containers e.g. containers having a wall thickness of less than 0.7 mm, especially a thickness of less than 0.5 mm and in particular a thickness of less than 0.4 mm.

A balanced runner system for injection moulding apparatus is disclosed. The runner system has an inlet, a plurality of runners and five gates. One of the gates is centrally located, the remaining gates being symmetrically spaced about the centrally located gate. The runners are such that the runner system is capable of supplying molten polymer to each gate at substantially the same rate. The runner system may be used to obtain a more uniform flow of molten polymer to a mould.

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Kingston, Canada

Peter J Lovell