Radiation crosslinked polyethylene hinge
AssigneeNOVA Chemicals (International) S.A.
InventorsJason Rycroft, Gilbert Arnould, Matthew Botros, William McGrory
Life of this patent
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Abstract
Polyethylene living hinges used in “snap top” lids for condiments and the like may be electron bean irradiated to partially crosslink the polyethylene to produce a hinge having an improvement in the number of opening and closing cycles until failure of not less than 30%. The irradiated lids may be used in place of polypropylene lids for condiment containers.
Claims22
A cap comprising a rim, a deck having an opening there through, and a cooperating lid attached to the rim by a hinge comprising one or more webs of injection or compression molded polyethylene wherein the polyethylene is chosen from high pressure polyethylene, Ziegler Natter catalyzed polyethylene, chromium catalyst polyethylene, single site catalyzed polyethylene, and mixtures thereof, each of said one or more webs having a thickness from 0.1 to 1 mm and having been radiation crosslinked and having a gel level not exceeding 35 wt. %;
- wherein the number of opening and closing cycles to break at a radial bend of 90°±20° at a temperature of 25° C. of the hinge is increased by not less than 30%, relative to the number of opening and closing cycles to break at a radial bend of 90°±20° at a temperature of 25° C. of a hinge of the same polyethylene and the same design which has not been irradiation crosslinked.
Dependencies are inferred from the claim text.