摘要:
A continuous process for the preparation of an isocyanate-terminated prepolymer having an NCO content in the range from 2 to 15% by weight, said process comprising the steps of :
(A) continuously delivering to a reaction zone an organic polyisocyanate composition and an isocyanate reactive compound having an average molecular weight of at least 1000 the relative proportions of isocyanate composition and isocyanate reactive compound being appropriate for the formation of a prepolymer having an NCO content in the indicated range; (B) allowing the isocyanate composition and the isocyanate reactive compound to react in the reaction zone to form an isocyanate-terminated prepolymer, and (C) continuously removing the prepolymer from the reaction zone.
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:
An internal mould release composition, suitable for use in the production of moulded articles by the RIM process, comprising : a) a metal salt of an organic acid, said metal salt having mould release properties, and b) a compatibilising amount of a guanidine or isourea compound of molecular weight below 1500.
摘要:
An internal mould release composition, suitable for use in the production of moulded articles by the RIM process comprising :
a) a metal salt of an organic acid, said metal salt having mould release properties, and b) a polymer having a molecular weight of at least 1500 containing at least two guanidine or isourea groups of the formula : wherein A represents and wherein each of Q¹ and Q², independently, represents hydrogen, alkyl or cycloalkyl and each of Q³ and Q⁴, independently, represents hydrogen, alkyl, cycloalkyl, arakyl or aryl.
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 continuous process for the preparation of an isocyanate-terminated prepolymer having an NCO content in the range from 2 to 15% by weight, said process comprising the steps of:
(A) continuously delivering to a reaction zone an organic polyisocyanate composition and an isocyanate reactive compound having an average molecular weight of at least 1000 the relative proportions is isocyanate composition and isocyanate reactive compound being appropriate for the formation of a prepolymer having an NCO content in the indicated range; (B) allowing the isocyanate composition and the isocyanate reactive compound to react in the reaction zone to form an isocyanate-terminated prepolymer, and (C) continuously removing the prepolymer from the reaction zone.
摘要:
The invention relates to a liquid isocyanate-containing prepolymer composition having an average isocyanate functionality greater than 2 and an NCO content of from 2 to 15 % by weight, as obtainable by reacting an isocyanate reactive polymer having an average nominal functionality of from 2 to 6 with a stoichiometric excess of a diphenylmethane diisocyanate composition containing at least 2 % by weight of 2,4'-diphenylmethane diisocyanate and having an average isocyanate functionality in the range from 2 to 2.3. The invention also relates to a method for preparing a polyurethane foam, which comprises reacting such a prepolymer composition with water.
摘要:
The invention relates to a liquid isocyanate-containing prepolymer composition having an average isocyanate functionality greater than 2 and an NCO content of from 2 to 15 % by weight, as obtainable by reacting an isocyanate reactive polymer having an average nominal functionality of from 2 to 6 with a stoichiometric excess of a diphenylmethane diisocyanate composition containing at least 2 % by weight of 2,4'-diphenylmethane diisocyanate and having an average isocyanate functionality in the range from 2 to 2.3. The invention also relates to a method for preparing a polyurethane foam, which comprises reacting such a prepolymer composition with water.