Reference

Methods for stabilization of oxalic acid-based polyesters

Methods for stabilization of oxalic acid-based polyesters. Cirule, I.; Alksnis, A.; Surna, J. (Inst. Khim. Drev., Riga, USSR). Deposited Doc., VINITI 2549-75, 12 pp. Avail. BLLD (Russian) 1975. DOCUMENT TYPE: Report CA Section: 36 (Plastics Manufacture and Processing) Dicyclohexylcarbodiimide (I) [538-75-0] and poly(dicyclohexenecarbodiimide) (II) [63812-89-5] introduced into molten ethylene glycol-oxalic acid copolymer (III) [27615-22-1] stabilized it by increasing the induction period preceeding the beginning of wt. loses (at 100.degree.) and the decreasing redued viscosity of III. The effectiveness of I and II was ascribed to their reaction with products of hydrolysis and free CO2H and OH groups of III. Addn. of (PhO)3P and of catalytic amts. of (BuO)4Ti was ineffective in stabilizing III. (BuO)4Ti in larger amts. accelerated the degrdn. of III.

Piperidinylguanidines

Piperidinylguanidines. Uhrhan, Paul; Lantzsch, Reinhard; Oertel, Harald; Roos, Ernst; Arlt, Dieter (Bayer A.-G., Ger.). Ger.In this study，538-75-0 is also used. Offen. DE 2551499 18 May 1977, 53 pp. (German). (Germany). CODEN: GWXXBX. CLASS: IC: C07D211-58. APPLICATION: DE 75-2551499 17 Nov 1975. DOCUMENT TYPE: Patent CA Section: 39 (Textiles) Section cross-reference(s): 27 The title compds. are prepd. by conventional methods and added to polyurethanes to prevent degrdn. and yellowing, esp. on exposure to light. Thus, 51.5 g dicyclohexylcarbodiimide [538-75-0] and 44.5 g 4-amino-2,2,6,6-tetramethylpiperidine [36768-62-4] were heated 6 h at 140.degree. and freed of volatiles in vacuo, giving 82 g N,N'-dicyclohexyl-N''-(2,2,6,6-tetramethyl-4-piperidinyl)guanidine (I) [62995-60-2]. A polyurethane was prepd. by heating adipic acid-1,6-hexanediol-2,2-dimethyl-1,3-propanediol polymer 1000, N-methylbis(2-hydroxypropyl)amine 19.8, diphenylmethane-4,4'-diisocyanate 280.7, and DMF 328 parts for 72 min at 45-50.degree., cooling, and mixing 748 parts of the prepolymer soln. with a soln. of H2NHCONHCH2CH2CONHNH2 33.7, water 67, and DMF 1570. The viscous soln. was pigmented with 4% (on solids) rutile, combined with 2.0% I, spun into 300 dtex fibers, and exposed in a fadeometer, giving tenacity 0.61 and 0.48 cN/dtex and elongation 590 and 540% after 0 and 44 h exposure, resp., compared with 0.53 and 0.22 cN/dtex and 620 and 436%, resp., for an unstabilized control. The stabilized fibers were colorless at exposure time up to 88 h, at which point the unstabilized control was yellow-brown. .