GB802324A - Process and apparatus for the production of porous or homogeneous polyurethane plastic semi-finished or finished articles or products - Google Patents

Abstract

<PICT:0802324/III/1> <PICT:0802324/III/2> Apparatus for the production of porous or homogeneous polyurethanes (see Group IV (a)) comprises a mixing chamber, a discharge opening at the top of the chamber, a plurality of inlet openings at the lower part of the chamber, pumps for supplying reaction components to the inlets under pressure, and a common heating bath, e.g. of water or oil, surrounding the mixing chamber and the pumps. Alternatively the mixing chamber, the pumps, and associated containers may each be arranged in a separate heating bath. In the apparatus shown in Fig. 2 a polyester is supplied through pipe 3 to mixer 4 by means of a gear-wheel pump; a cross-linking agent, e.g. butylene glycol, and an isocyanate are injected through pipes 8, 12 respectively by high pressure piston pumps. Stirrer 19 assists mixing and the final product leaves at 20 and is introduced into moulds. The pressure at which the components are fed to the mixing chamber may be from 20 to 1000 atmospheres. In a modification, Fig. 3, the mixing chamber 25 contains a stirrer 27 which may be raised or lowered by moving spindle 37 to vary the size of the reaction space and thus the reaction time; cams or protrusions 28 are provided on the stirrer. In an alternative arrangement, reaction components are injected into a flowing stream of the main component before it reaches the mixer. Specification 769,680, [Group IV (a)], is referred to.ALSO:Porous or homogeneous polyurethane products or articles are formed by injecting one or more of the reaction components into a flowing stream of a main component, the mixture passing upwardly through a reaction vessel, with or without stirring, and being filled into moulds. In this way the formation of bubbles in the product is prevented. One of the reactants may be a polyester, polyester amide, or polyethylene glycol; the polyesters may be derived from malonic, succinic, adipic, methyl adipic, sebacic, dihydromucic, thiodipropionic, maleic, phthalic, terephthalic, tricarballylic, or tartaric acid, ethylene glycol, di-, tri- or poly-ethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,6-hexanediol, glycerine, pentaerythritol, trimethyol propane, hexanetriol, ethylene diamine, tetramethylene diamine, hexamethylene diamine, N-methyl dipropylene triamine, piperazine, phenylene and naphthylene diamines, ethanolamine, propanolamine, N-methyl diethanolamine, and hydroxyethyl aniline; another reactant may be a polyisocyanate, diisocyanate, or mixture thereof, examples being hexamethylene, toluylene, naphthylene, phenylene, 1 - isopropyl - 2,4 - benzene, and 4,41-diphenyl methane diisocyanates, and diphenyl 4,2,41-triisocyanate. Butylene glycol may be added as a cross-linking agent. The mixing vessel, feed pumps and supply containers for the reactants may all be arranged in a water or oil heating bath, or may be arranged in separate baths. The pressure at which the components are fed to the mixing vessel may be from 20 to 1000 atmospheres. In one form of the mixing chamber, the stirrer is adjustable so as to vary the size of the reaction space, and thus the reaction time. Specification 769,680, [Group IV (a)], is referred to.