Process for the production of elastic tapes from polyurethane
AssigneeWolff Walsrode AG
InventorWolfgang Ermert
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Abstract
Process for the production of elastic tapes from thermoplastic polyurethane elastomers, wherein the thermoplastic is extruded to form a flat or tubular film and is slit in the usual manner, the extruded film being oriented lengthwise at least in the ratio of 1:1.5, cooled and stored until the modulus of elasticity has increased by at least 25%, measured according to DIN 53,455, before the film is slit, and the use of these tapes for the production of elastic seals.
Claims4
In the production of elastic tapes by extruding a thermoplastic polyurethane elastomer to form a flat or tubular film, orienting the film and slitting the film into tapes, the improvement which comprises orienting the extruded film lengthwise with a take-off ratio of at least 1:1.5, cooling the film and storing it under tension until the modulus of elasticity, according to DIN 53,455, has increased by at least 25% prior to slitting, including the additional steps of stretching the tape, bonding the stretched tape to a substrate with a hot melt adhesive, cooling and releasing the stress, and subjecting the substrate-tape structure to a further heat treatment to shrink said tape.
Dependencies are inferred from the claim text.