abstract |
Flexible, semi-rigid, and rigid vinyl chloridenpolymer compositions comprising a latent mercaptan-containingnheat stabilizer are substantially free from thenoffensive odour typically associated with mercaptans andnare protected during processing by the degradationnproducts of the latent (i.e., blocked) mercaptan whichninclude a free mercaptan. The free mercaptan thusnreleased enhances the activity of metallic-based heatnstabilizers such as zinc carboxylates and organotinncarboxylates and mercaptides in the polymer composition.nOther products of the degradation are believed to includencarbocations of the blocking moiety which are stabilizednby a molecular structure in which the electron deficiencynis shared by several groups. The latent mercaptan isnselected from a 2-S-(tetrahydropyranyl)-thioalkanol, ancarboxylic acid ester thereof, a 2-S-(tetrahydropyranyl)-thioglycolicnacid, and an ester thereof. |