GB820266A - Process for the manufacture of porous or homogeneous polyurethane plastics - Google Patents

Abstract

A process for the production of polyurethane plastics by the reaction of an organic compound containing at least two reactive hydrogen atoms with a polyisocyanate and a cross-linking agent and/or an accelerator, comprises injecting at least one but less than all of the three last-mentioned reactants into a stream of the organic compound containing at least two reactive hydrogen atoms in a first mixing zone, and injecting the remaining component or components into the mixture thus obtained in a second mixing zone. The process is suitably carried out in the apparatus described in Specification 820,265. The injection pressure may be 300 to 15,000 lbs./sq. inch. Preferably the polyisocyanate or the cross-linking agent and/or accelerator is or are injected into a stream of the organic compound having at least two reactive hydrogen atoms or of a prepolymer prepared from such a compound. This is followed by the injection in a second step of the cross-linking agent and/or accelerator or polyisocyanate, and if desired, of an additional amount of the compound having two reactive hydrogen atoms. The process is applicable to the production both of homogeneous and porous polyurethanes. The compound having reactive hydrogen atoms may be a polyester, polyalkylene ether glycol or a hydrogenation product of olefine-carbon monoxide copolymers. Water, glycols and diamines are suitable cross-linking agents and tertiary amines and heavy metal compounds are suitable accelerators. Emulsifiers may be added to the mixture. In a typical example, using the apparatus of Specification 820,265 an activator mixture consisting of N-diethyl-b -phenoxyethylamine and the sodium salt of sulphonated castor oil in water is injected into a mixture of an adipic acid/phthalic anhydride/hexanetriol polyester, an adipic acid/hexanetriol/butanediol polyester and ethoxylated trimethylol propane in a mixing zone. The mixture obtained is then passed to a mixing head in which toluylene diisocyanate is injected and the mixture is then passed out through a nozzle.ALSO:A process for the production of polyurethane plastics (which may be porous) by the reaction of an organic compound containing at least two reactive hydrogen atoms with a polyisocyanate and a cross-linking agent and/or an accelerator, comprises injecting at least one but less than all of the three least-mntioned reactants into a stream of the organic compound containing at least two reactive hydrogen atoms in a first mixing zone, and injecting the remaining component or components into the mixture thus obtained in a second mixing zone. The process is suitably carried out in the apparatus described in Specification 820,265. The injection pressure may be 300 to 15,000 lbs./sq. inch. Preferably the polyisocyanate or the cross-linking agent and/or accelerator is or are injected into a stream of the organic compound having at least two reactive hydrogen atoms or of a prepolymer prepared from such a compound. This is followed by the injection in a second step of the cross-linking agent or/and accelerator or polyisocyanate, and if desired, of an additional amount of the compound having two reactive hydrogen atoms. The process is applicable to the production both of homogeneous and porous polyurethanes. The compound having reactive hydrogen atoms may be a polyester, polyalkylene ether glycol or a hydrogenation product of olefine-carbon monoxide copolymers. Water, glycols and diamines are suitable cross-linking agents and tertiary amines and heavy metals compound are suitable accelerators. Emulsifiers may be added to the mixture. In a typical example, using the apparatus of Specification 820,265 an activator mixture consisting of N-diethyl-b -phenoxyethylamine and the sodium salt of sulphonated castor oil in water is injected into a mixture of an adipic acid/phthalic anhydride/hexanetriol polyester, an adipic acid/hexanetriol/butanediol polyester and ethoxylated trimethylol propane in a mixing zone. The mixture obtained is then passed to a mixing head in which toluylene diisocyanate is injected and the mixture is then passed out through a nozzle.