摘要:
A polyisocyanate composition, suitable for use in the production of elastomers by the RIM process, said composition being the product of reacting an alcohol and/or thiol having an average hydroxyl and/or thiol functionality of from about 1.5 to about 4 and an average hydroxyl and/or thiol equivalent weight of at least 500 with at least 2 equivalents, per hydroxyl and/or thiol equivalent, of an organic polyisocyanate under such conditions that at least about 20 % of the initially formed urethane and/or thiourethane groups are converted to allophanate and/or thioallophanate groups.
摘要:
Reaction system for preparing elastomers according to the RIM process, the system comprising an allophanate modified polyisocyanate, a polyol and an aromatic polyamine chain extender. No IMR is necessary.
摘要:
A process for making integral skin foams which comprises reacting into a closed mould :
A) an organic polyisocyanate B) an isocyanate-reactive composition comprising :
(i) a catalytically effective amount of a urethane-promoting catalyst and optionally a urea-promoting catalyst, (ii) a catalytically effective amount of a carbodiimide-promoting catalyst, and (iii) an isocyanate-reactive compound; in the presence of
C) an inert physical blowing agent.
The process provides integral skin foams having good skin properties at reduced physical blowing agent levels.
摘要:
Polyurethane/urea foams are derived from prepolymers having branched chain linked isocyanate end groups and components containing isocyanate reactive imino/enamino-functional compounds.
摘要:
A polyisocyanate composition, suitable for use in the production of elastomers by the RIM process, said composition being the product of reacting an alcohol and/or thiol having an average hydroxyl and/or thiol functionality of from about 1.5 to about 4 and an average hydroxyl and/or thiol equivalent weight of at least 500 with at least 2 equivalents, per hydroxyl and/or thiol equivalent, of an organic polyisocyanate under such conditions that at least about 20 % of the initially formed urethane and/or thiourethane groups are converted to allophanate and/or thioallophanate groups.
摘要:
A process for preparing polymeric foams which comprises reacting : a) an organic polyisocyanate b) an isocyanate-reactive composition comprising : i) an organic polyfunctional isocyanate reactive composition comprising at least 50% w of polyfunctional isocyanate reactive compounds having a molecular weight of above 1500 wherein at least 25% of the isocyanate reactive groups are imino or enamino groups, and at most 50% by weight of polyfunctional isocyanate reactive compounds having a molecular weight of 60-1500, and ii) a catalytically effective amount of a carbodiimide promoting catalyst, and iii) optionally other catalysts and/or further conventional additives, in the substantial absence of water and chlorofluorocarbon blowing agent.