Multi-layer, pre-stretched elastic articles
AssigneeDow Global Technologies LLC
InventorsRajen M. Patel, Andy Chang
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Abstract
In one embodiment the invention is an article comprising at least two layers, a first or low crystallinity layer comprising a low crystallinity polymer and a second or high crystallinity layer comprising a high crystallinity polymer. The high crystallinity polymer has a melting point as determined by differential scanning calorimetry (DSC) that is about the same or within less than 25 C of the melting point of the low crystallinity polymer. The article is elongated at a temperature below the melting point of the low crystallinity polymer in at least one direction to an elongation of at least about 50% of its original length or width, to form a pre-stretched article. Preferably, the high crystallinity layer is capable of undergoing plastic deformation upon the elongation.
Claims56
An article having at least two layers, the article comprising (a) a low crystallinity layer comprising a low crystallinity polymer, and (b) a high crystallinity layer comprising a high crystallinity polymer having a melting point as determined by DSC that is less than that of the low crystallinity polymer, wherein the article has been elongated below the melting point of the low crystallinity polymer in at least one direction to an elongation of at least 50% of its original length or width, and further wherein the low crystallinity polymer and high crystallinity polymer have a weight percent crystallinity difference of at least about 1%.
An article having at least two layers, the article comprising (a) a low crystallinity layer comprising a low crystallinity polymer comprising a copolymer of propylene and ethylene, and (b) a high crystallinity layer in contact with the low crystallinity layer and comprising a high crystallinity polymer comprising a copolymer of propylene and ethylene and having a melting point as determined by DSC that is less than that of the low crystallinity polymer, wherein the high crystallinity polymer has a weight percent crystallinity at least 18.5% higher than the low crystallinity polymer.
Dependencies are inferred from the claim text.