Abstract:
The invention relates to transparent, autoclavable, non-cytotoxic, essentially compact polyurethane embedding compositions which are prepared by reacting a) modified diphenylmethane diisocyanates with b) compounds with at least two reactive hydrogens, which contain or are composed of b1) at least one polyether-polyol with an average functionality of from 3 to 8, a hydroxyl number of from 200 to 1000 and an alkali metal ion content of from 150 to 1200 ppm or, preferably, a mixture of (b1) and castor oil and/or at least one polyetherpolyol (b2) with a functionality of from 2 to 3, a hydroxyl number of from 90 to 200 and an alkali metal ion content of less than 10 ppm in the presence or absence of c) catalysts and to a process for preparing the polyurethane embedding compositions and to the use thereof for articles used in medicine.
Abstract:
The invention relates to a process for the production of polyurethane foams, preferably semirigid polyurethane foams, having an improved foam structure by reacting a) organic and/or modified organic polyisocyanates with b) polyhydroxyl compounds having at least 2 reactive hydrogen atoms and c) crosslinking agents comprising at least one polyoxyalkylene polyol having a mean functionality of 3 to 8 and a hydroxyl number of from 200 to 1300 ppm, and having an alkali ion content of from 150 to 1200 ppm, in the presence of d) blowing agents, e) optionally catalysts, f) inorganic and/or organic acids as additive and g) optionally auxiliaries.
Abstract:
An isocyanate prepolymer mixture (I) containing urethane groups and reactive isocyanate (NCO) groups is claimed. It has an NCO content of 2.5-30 wt.% and is obtained by reacting (a) di- and/or polyisocyanate(s) with (b) a solution or emulsion containing (b-1) oligosaccharide(s) and/or polysaccharide(s), (b-2) non-aqueous solvent(s) reacting with (b-1) and optionally (b-3) polyhydroxyl compound(s). Also claimed is a method of producing compact or cellular polyurethane, especially polyurethane foam from (I), the polyurethane per se and mouldings of this polyurethane.
Abstract:
The invention relates to a process for the preparation of elastic, cellular or compact elastomers containing bonded urethane groups or urethane and urea groups, preferably elastomer mouldings, in particular airbag covers, by reacting a) at least one organic and/or modified organic polyisocyanate with b) at least one relatively high-molecular-weight compound containing at least two reactive hydrogen atoms, c) at least one N-perethoxylated polyoxyalkylene-polyamine and d) low-molecular-weight chain extenders and/or crosslinking agents, in the presence or absence of e) catalysts, f) auxiliaries and g) blowing agents, in a mould.o
Abstract:
NCO-prepolymer mixt. (I) contg. urethane gps.and 2.5-30 wt.% reactive NCO is claimed. (I) is obtd. by reacting (a) 4,4'-, 2,4'- and 2,2'-di-phenylmethane diisocyanate, an isomer mixt. of 4,4'- and 2,4'-and opt. 2,2'-di-phenylmethane diisocyanate or a mixt. of diphenylmethane diisocyanates and poly-phenyl-polyphenylene polyisocyanates with (b) a suspension contg. (b-1) polyoxypropylene glycol(s) (IIA) and/or polyoxypropylene-polyoxyethylene glycol(s) (IIB) with a mol.wt. of 400-6000, pref. 1000-3000 and (b-ii) lignin. Also claimed are methods for producing (1) (I) by reacting the specified organic polyisocyanates and suspension; and (2) compact or cellular polyurethanes, pref. PU foam.
Abstract:
An NCO-prepolymer mixt. (I) contg. urethane gps. and 2.5-30 wt.% reactive NCO gps. is obtd. by reacting: (a) 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate, an isomer mixt. of 4,4'- and 2,4'- and opt. 2,2'-diphenylmethane diisocyanate or a mixt. of diphenylmethane diisocyanates and polyphenyl-polyphenylene polyisocyanates; and(b) a soln. contg.: (b-i) polyoxyethylene glycol(s) (PEG) with a mol.wt. of 400-4000; and (b-ii) lignin. Also claimed are:(A) a method for producing (I) by reacting the specified organic polyisocyanates and soln.; and (B) a method for producing compact or cellular polyurethanes, pref. polyurethane foam.
Abstract:
Prodn. of polyurethane foam involves reacting (a) organic and/or modified organic polyisocyanate(s) with (b) polyol(s) of relatively high mol. wt., which contain at least 2 reactive H atoms and (c) opt. low mol. chain extender and/or crosslinker in the presence of (d) blowing agent, (e) catalyst and (f) opt. additives. The novelty is that the catalyst comprises aminoalkyl- or aminophenyl-imidazole cpds. of formula (IA) and/or (IB). In (IA) and (IB), R ,R , R = 1-10C alkyl, 1-4C alkoxy, N-mono- and N,N-di-(1-4C)-alkylamino, N-mono- and N,N-di-(1-4C)-alkylamino-(2-4C)-alkylene, Ph, halogen or H; R = as R except halogen and alkoxy; X = 2-6C alkylene or phenylene; Y = H, 2-4C hydroxyalkyl or hydroxypoly-(2-20C)-oxyalkylene; Z = 1-4C alkyl, Ph or as Y. Also claimed is the use of (IA) and/or (IB), esp. 1-(3-aminopropyl)-imidazole (IC), 1-(3-aminopropyl)-2-methylimidazole (ID) or 1-(3-aminopropyl)-2-ethyl-4-methylimidazole (IE) as catalyst for the prodn. of polyisocyanate polyadducts.
Abstract:
The invention relates to a process for the preparation of open-cell, flexible polyurethane foams using, as cell opener, a polyetherol which can be prepared by the addition reaction of ethylene oxide and propylene oxide onto hydroxyl-containing initiator substances with basic catalysis and which has a hydroxyl number of from 30 to 60 mg of KOH/g, an ethylene oxide content of from 60 to 80% by weight of the total amount of alkylene oxide, a primary hydroxyl group content of 70% of the total hydroxyl group content and a functionality of from 2.5 to 3.5.