Biodegradable thermoplastic polyurethane filaments for incontinence articles - obtd from reaction prod of mixt of aliphatic polyester-poly:ol and polyether-poly:ol with aliphatic poly:isocyanate and diol chain extender for nappies and sanitary towels.

摘要

The thermoplastic polyurethane (TPU) filaments (I) are claimed. (I) are obtd by reacting (A) 100 pts wt polyol mixt with (B) 1,6-hexamethylene di-isocyanate (HDI), IPDI or dicyclohexyl methane-4,4'-di-isocyanate (DCMDI) and (C) 1,4-butanediol and/or 1,6-hexane diol chain extender, with NCO index (NI)= 97-99, equiv ratio (B):(A)= (2.8:1.0)-(12.0:1.0) and equiv ratio (C):(A)= (1.75:1.0)-(11.3:1.0) (with NI= equiv ratio (NCO)/(total OH in A and C) x 100). Mixt (A) contains 70-90 pts wt polyester-polyol with mol wt 2000 based on adipic acid and ethane-diol, butane diol, hexane diol, diethylene glycol or neopentyl glycol, and 10-30 pts wt polyether-polyol based on PEG with mol wt 800-4000. USE/ADVANTAGE - Used for the prodn of incontinence articles (claimed). (I) are biodegradable, elastic filaments made of melt-spinnable TPU. Prods mfd from (I) (eg nappies, sanitary towels) are completely decomposed after 8 weeks on a rubbish tip by hydrolysis of the polyester segments (even at 23 deg C and 30% RH), followed by degradation by enzymes and micro organisms; without hydrophilic polyether gps in the TPU flexible segment, 4 months is required for a significant redn in strength, with no noticeable degradation of the polyurethane. The use of sub-stoichiometric amts of isocyanate (NI= 97-99), and the 1-stage method of prepn, rules out side reactions giving gelled, partly-crosslinked polymer and ensures a perfect melt flow for the spinning process.