GB1185151A - Improvements relating to the Production of Artificial Spandex Filaments - Google Patents

Abstract

1,185,151. Making spandex filaments. COURTAULDS Ltd. 14 July, 1967 [15 July, 1966], No. 31909/66. Heading B5B. [Also in Division C3] In the manufacture of spandex filaments by reacting an hydroxyl terminated polyester or polyether with an excess of a diisocyanate of the type OCN-R-NCO in which R is a divalent hydrocarbon radical to form a spandex precursor and extruding a solution of the precursor into a coagulating or spinning bath containing a difunctional compound capable of reacting with isocyanate groups to form the spandex polymer in filament form, a substituted phenol is added to the preformed polyester or polyether, in a minor proportion based on the weight of the polyester or polyether, before the polyester or polyether is reacted with the diisoyanate, and after the filaments have been produced and have been withdrawn from the spinning bath, they are stretched in the never-dried state and heated while they are so stretched, e.g. during the drying of the filaments. The substituted phenol contains, in addition to at least one OH group, at least one further group, such as an amino, nitro, halo or substituted alkyl group. The preferred compound is "bisphenol A" (i.e. p-p<SP>1</SP>-isopropylidene diphenol). In an example, a polyester of molecular weight about 3100 is prepared by heating together ethylene glycol, propylene glycol, glycerol and adipic acid; 2% of bisphenol A, based on the weight of the polyester, and p-p<SP>1</SP>-diphenylmethane diisocyanate are added. The reaction mixture is diluted to 88% solids content with tetrahydrofuran and the solution obtained is extruded into a 12% solution of ethylene diamine is isopropyl alcohol. The filaments thereby formed are removed from the spinning bath, washed with water to remove adherent spinning bath constituents, stretched 85% and then dried while so stretched on a reel heated to 180‹ C.