Polyurethane foam composition convertible in the process to produce a foam resin polimocesso to produce a foam polyurethane and polyurethane flexible foam espetanaA polyurethane resin and polyurethane flexible foam.

摘要

A block copolymer, useful as a stabilizer for polyurethane foams, comprises at least one block of at least two siloxane units of the formula FORM:1015611/C3/1 , wherein R is a monovalent or divalent hydrocarbon radical and b is 1, 2 or 3, at least one R in at least one of the units being a divalent hydrocarbon radical, and at least one oxyalkylene block of a least four oxyalkylene units, the siloxane and oxyalkylene blocks being interconnected by the divalent hydrocarbon radical. The siloxane block may also contain additional units of the formula FORM:1015611/C3/2 , wherein e is 0, 1 or 2, f is 1 or 2 and e + f is 1, 2, or 3. The block copolymers may contain at least unit of the formula FORM:1015611/C3/3 FORM:1015611/C3/4 or FORM:1015611/C3/5 wherein G is an alkyl, alkenyl or aryl radical, G11 is an alkylene radical of at least 2 C atoms, G111 is H or a monovalent hydrocarbon radical free of aliphatic unsaturation, c is 0, 1 or 2 in (1) and 0 or 1 in (3), and n is at least 4 and preferably is from 4 to 30. The copolymers can be made (1) by reacting a siloxane polymer containing a Si-bonded halohydrocarbon radical with an alkali metal salt of an oxyalkylene polymer to yield a copolymer which may, if desired, contain some -OM (where M is an alkali metal) groups to serve as "built in" basic catalysts for subsequent equilibration, or (2) by reacting a siloxane containing Si-H with an alkenyloxy-terminated oxyalkylene polymer. The copolymers may be equilibrated with conventional siloxanes in known manner. Examples describe the second method of making the copolymers. The copolymers are incorporated, as foam stabilizers, in polyurethane foam-forming compositions comprising an active hydrogen-containing polyether, an organic isocyanate or isothiocyanate, a catalyst for the reaction and, optionally, a blowing agent. Numerous examples of the components of the compositions are given. The foams are made by known methods, a useful one comprising (1) combining at 15 DEG to 20 DEG C. separate mixtures of (a) a polyether, an organo-tin catalyst, a t-amine catalyst and water; and (b) an organic isocyanate and the stabilizer; (2) maintaining the mixture at 15 DEG to 20 DEG C. until foaming commences; (3) pouring the foaming mixture into a mould maintained at 15 DEG to 50 DEG C.; and (4) curing the resulting foam at 100 DEG to 150 DEG C. Examples are given.