Thermoformed articles from sheet incorporating cycloolefin copolymer

摘要

Thermoformed articles include cycloolefin/ethylene copolymer and LLDPE. The articles are formed with an areal draw ratio of 1.5 and greater and exhibit unexpectedly elevated stiffness along with ductility suitable for forming deep-draw parts. Multilayer sheet is used for achieving a desired set of properties.

主权项

1. A thermoformed article prepared from a sheet including linear low density polyethylene (LLDPE) and cycloolefin/ethylene copolymer, the cycloolefin copolymer being present in an amount of from about 5 weight percent to about 45 weight percent based on the weight of the sheet,
the sheet having a thickness of from about 3 mils to about 20 mils and exhibiting a relative machine direction (MD) modulus of at least 2 as compared to the LLDPE in the sheet as well as a relative MD elongation of greater than 0.5 as compared with the LLDPE in the sheet, wherein the relative MD modulus and the relative MD elongation as compared to the LLDPE in the sheet refers to the ratio of MD modulus of the sheet or MD elongation of the sheet to that of another sheet made exclusively from the LLDPE in the sheet and having the same geometry and which is made by the same process, the thermoformed article being further characterized by having an areal draw ratio of at least 1.5 with respect to the sheet from which it is formed, said article defining a thermoformed cavity having an average thermoformed cavity thickness corresponding to the product of the initial thickness of the film prior to thermoforming and the reciprocal of the of the areal draw ratio.