Patent GB-845206-A (GB)
Title: Mixing apparatus
IPC: B29B7/00
Filed: 1957-03-22
Abstract: <PICT:0845206/IV(a)/1> A mixing apparatus comprises a reservoir zone into which some or all of the ingredients to be mixed are fed, and a mixing zone, said reservoir zone being separated from said mixing zone by a weir-like barrier over which the ingredients flow from the reservoir zone to the mixing zone, and said mixing zone being provided with inlet ports for any ingredients not fed into the reservoir zone and with mixing means and an exit port below the level of the weir-like barrier.  The apparatus is useful in the p production of foamed or homogeneous polyurethanes.  Polyester or other hydroxyl-containing polyurethane-forming material and polyisocyanate are fed separately into ports D and E and activator mixture is fed into F.  Stirrer G mixes the reactants and the product is discharged through I, the rate of flow of reactants being such that there is no build up of material in mixing zone C tending to flow back over weir B.  Then may also be an auxiliary stirrer H in the reservoir zone A.  At the end of a run the flow of activator and polyisocyanate components is stopped first and the reservoir which is then filled with polyhydroxylic material alone prevents ingress of moisture to the polyisocyanate supply. The mixing head may have an outer jacket for the circulation of cooling liquid.  Examples described the preparation of foamed polyurethanes in such an apparatus from starting materials selected from diethylene glycol/pentaerythritol/adipic acid or pentaerythritol/12:3-butylene glycol/adipic acid polyesters, a polyoxypropylene glycol and a prepolymer from polyoxypropylene glycol and trimethylol propane and tollylene diisocyanates. Tolylene 2:4 and 2:6- diisocyanates and the crude product obtained by phosgenating a formaldehydeaniline condensation product (see Group IV (b)) are the specified polyisocyanates.  Tertiary amines, emulsifying agents such as sulphonated or sulphatedoils, silicones, flame-proofing agents (e.g., tri-b -chlorethyl phosphate) are other specified ingredients. Activation mixtures may contain dimethylcyclohexylamine, alkylphenolethylene oxide condensates, diethylaminoethyl adipate, diethylamine oleate, sulphated methyl oleate, N:N-diethylaminopropionamide or N:N-diethylaminopropyl succinimide.  Specification 839,183 is referred to.ALSO:A diphenylmethane diisocyanate. for use in preparing polyurethanes (see Group IV(a)) is prepared by reacting one mole of formaldehyde, 4 moles of aniline and one mole of hydrochloric acid. The crude product of 2:41- and 4:41- diaminodiphenylmethane, containing 15% of polyamines (mainly triamines) is converted to a mixture of the corresponding isocyanates by treatment in o-dichlorobenzene with phosgene, firstly at 0  DEG C. and subsequently at 165 to 175  DEG C.ALSO:<PICT:0845206/III/1> A mixing apparatus comprises a reservoir zone into which some or all of the ingredients to be mixed are fed, and a mixing zone, said reservoir zone being separated from said mixing zone by a weir-like barrier over which the ingredients flow from the reservoir zone to the mixing zone, and said mixing zone being provided with inlet ports for any ingredients not fed into the reservoir zone, and with mixing means and an exit port below the level of the weir-like barrier.  The apparatus is useful in the production of foamed or homogeneous polyurethanes.  Polyester or other hydroxyl-containing polyurethane-forming material and polyisocyanate are fed separately into ports D and E and activator mixture is fed into F.  Stirrer G mixes the reactants and the product is discharged through I, the rate of flow of reactants being such that there is no build up of material in mixing C tending to flow back over weir B.  There may also be an auxiliary stirrer H in zone A.  At the end of a run the flow of activator and polyisocyanate components is stopped first and the reservoir, which is then filled with polyhydroxylic material alone, prevents p  ingress of moisture to the polyisocyanate.  The mixing head may have an outer jacket for the circulation of cooling liquid. Specification 839,183 is referred to.