Patent GB-1492838-A (GB)
Title: Conversion of scrap polyurethane foam to polyols
IPC: C07C67/00
Filed: 1975-04-07
Abstract: 1492838 Conversion of scrap polyurethane foam to polyols UPJOHN CO 7 April 1975 [29 April 1974] 14186/75 Heading C3R A process for converting scrap polyurethane foam, which foam, or at least a part of it, is a flexible foam derived from a polyether polyol, to a homogeneous mixture of polyols comprises heating the said scrap foam at a temperature of 180‹-250‹ C. with an aliphatic diol of the formula HO-A-OH wherein A is selected from a C 2 -C 6  alkylene radical and a C 2 -C 6  alkylene-ether radical, both of which radicals carry at least one C 1 -C 6  alkyl substituent on a carbon atom in the chain thereof, said diol being present in an amount by weight which does not exceed the total weight of said scrap foam, so as to result in a single phase product consisting essentially of a homogeneous mixture of polyols. The scrap flexible foam may be used in combination with scrap from a foam selected from semi-rigid or rigid polyurethane foam, or rigid polyisocyanurate foam for example in an amount up to 75% by weight based on the weight of the scrap flexible foam. Suitable diols are 1,2-propylene glycol, 1,2-butanediol, 1,2-hexanediol, di-(1,2-propylene glycol), di-(1,2-butylene glycol), 3-methylpentane-1,5-diol, 2,2-dimethyl- 1,3-propanediol and 1,2-octanediol and mixtures thereof. The process can be carried out continuously. The product generally has an OH equivalent weight of 65-120 and a viscosity of 300-4500 cs at 25‹ C., and can be reused in the manufacture of polyurethane foams. In Examples 1-3, 5 and 6 scrap foam prepared from the following formulation toluene diisocyanate, propoxylated glycerol, stannous octoate, -N-ethylmorpholine, triethylene-diamine, a surfactant and water, is converted to a homogeneous mixture of polyols by heating with 1,2- propylene glycol or 1,2-butanediol or 3-methyl pentane 1,5-diol. In Example 8 a scrap mixture of a commercial flexible polyether-based polyurethane foam and a semi-flexible polyurethane foam prepared from polymethylene polyphenyl polyisocyanate, propoxylated trimethylolpropane, a blend of N,N-di-(2-hydroxypropyl) aniline and a polyol derived from nonylphenol, diethanolamine and formaldehyde capped with propylene-oxide, N,N<SP>1</SP>,N<SP>11</SP>-tris-(dimethylaminopropyl) hexahydrotriazine, triethanolamine, water dibutyltin dilaurate and trichlorofluoromethane is converted to a mixture of polyols by heating with 1,2-propylene glycol. In Example 9 a polyurethane scrap mixture of a commercial flexible polyether-based foam and a rigid foam prepared from a propoxylated polymethylene polyphenyl polyamine, a propoxylated glycerol, an adduct of phosphoric acid and propylene oxide, trimethylol propane, an organosilicone surfactant, water, tetramethylguanidine, tetramethylbutane diamine, trichlorofluoromethane and polymethylene polyphenyl polyisocyanate is converted to a mixture of polyols as in Example 8. In Example 10 a mixture of polyols prepared by heating scrap from a commercial flexible polyether-based polyurethane foam with 1,2-propylene glycol is used to prepare a rigid foam using a reaction mixture additionally comprising a propoxylated polymethylene polyphenyl polyamine, a propoxylated glycerol, triethylenediamine, an organosilicone surfactant, trichlorofluoromethane and polymethylene polyphenyl polyisocyanate.