Patent GB-890045-A (GB)
Title: Production of foamed resins
IPC: B29C44/36
Filed: 1958-10-29
Abstract: <PICT:0890045/III/1> In a continuous process for producing a foamed polyurethane resin, a liquid reaction mixture is passed from a mixer 14 through a restricted passageway 25 between a rigid projection 26 and one face of a flexible, e.g. butyl rubber, diaphragm 28, whose other face is subjected to fluid, e.g. air, pressure indicated on a gauge 36 and controlled by a valve 38.  In response to changes in pressure, e.g. caused by the generation of carbon dioxide gas in the reaction mixture, the diaphragm 28 moves towards or away from the projection 26 to decrease or increase the cross-sectional area of the passageway, thus tending to maintain uniformity in the rate of flow and pressure of the liquid passing therethrough and in the size of the pores or cells in the foamed resin.  The foamed liquid resin then passes through an outlet 32 into moving pans &c. (not shown) wherein it solidifies.  The reaction mixture may comprise a polyester, polyesteramide or polyether or a prepolymer thereof, a polyisocyanate and/or a polyisothiocyanate and, optionally, a catalyst, which react with evolution of carbon dioxide. Specification 890,044 and U.S.A. Specifications 2,577,279, 2,602,783 and 2,764,565 are referred to.ALSO:<PICT:0890045/IV (a)/1> In a continuous process for producing a foamed polyurethane resin, a liquid mixture comprising a polyester, polyesteramide or polyether or a prepolymer thereof, a polyisocyanate and/or a polyisothiocyanate and, optionally, a catalyst, which react, with evolution of carbon dioxide gas, to form the resin, is passed from a mixer 14 through a restricted passageway 25 between a rigid projection 26 and one face of a flexible, e.g. butyl rubber, diaphragm 28, whose other face is subjected to fluid, e.g. air, pressure indicated on a gauge 36 and controlled by a valve 38. The foamed liquid resin then passes through an outlet 32 into moving pans &c. (not shown) wherein it solidifies.  In response to changes in pressure caused by the generation of carbon dioxide gas in the mixture, the diaphragm 28 moves towards or away from the projection 26 to decrease or increase the cross-sectional area of the passageway, thus tending to maintain uniformity in the rate of flow and pressure of the liquid passing therethrough and in the size of the pores or cells in the foamed resin.  A polyester, exemplified, is produced by reacting diethylene glycol with adipic acid and trimethylol propane.  Other suitable polyesters are produced by reacting succinic, adipic, sebacic, isosebacic, azelaic, citric, lactic, phthalic or terephthalic acid, phthalic or maleic anhydride with ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1.4 butylene glycol, glycerol, trimethylol propane, pentaerythritol, mannitol or sorbitol or mixtures thereof, e.g. in the presence of oleic acid, castor oil, linseed oil, copal resin, rosin, sodium acetate trihydrate, manganous chloride tetrahydrate, cupric nitrate hexahydrate, magnesium bromide hexahydrate, lithium salicylate hemihydrate, calcium chloride hexahydrate or a non-ionic wetting agent.  Suitable polyethers are polyethylene and polypropylene glycols having molecular weights between 1,000 and 4,000, graft polymer mixtures of polyethylene and polypropylene glycols and condensates of ethylene and propylene oxide with glycerine, hexane triol, trimethylol propane or an amine, having molecular weights between 2,000 and 4,000.  Polyisocyanates specified are m-toluene di-isocyanate, e.g. mixed with 4% by weight of ethyl cellulose; p-toluene di-isocyanate; diphenyl di-isocyanate triphenyl di-isocyanate; diphenylmethane di-isocyanate; ethylene di-isocyanate; m- and p-phenylene di-isocyanate; propylene 1,2, di-isocyanate and triphenylmethane tri-isocyanate.  The polyisocyanate may be used in the form of an addition product, described in U.S.A.  Specification 2,602,783, with 1,5 pentane diol; 2-methyl-2,4, pentane diol; 1,4-hexane diol; ethylene or diethylene glycol; resorcinol; pyrocatechol; pyrogallol; aluminium monostearate, monooleate or monopalmitate; bismuth monostearate; 2-amino 1-butanol; 1,3-amino 2-propanol or a polyfunctional aliphatic or aromatic amine or thioglycol.  Catalysts specified are:-N-methyl morpholine; N-ethyl morpholine, e.g. mixed with N-coco morpholine, an emulsifier and water; trimethyl or triethyl amine; dimethyl or diethyl hexahydroaniline and piperazine. Specification 890,044 and U.S.A. Specifications 2,577,279 and 2,764,565 also are referred to.