GB753299A - Improvements in or relating to formaldehyde polymers - Google Patents

Abstract

Solid formaldehyde polymers having a reaction rate constant for thermal degradation at 222 DEG C., preferably less than 1 per cent by weight per minute, a degree of toughness at least 1, and preferably an inherent viscosity of at least 1.0 measured as a 0.5 per cent solution at 60 DEG C. in p-chlorophenol containing 2 per cent alphapinene, are made by passing gaseous, substantially anhydrous, monomeric formaldehyde into a reaction medium which is inert under the conditions of the reaction and polymerizing the formaldehyde continuously as it is introduced into the zone. The polymerization may be effected in the presence of a catalyst which may be added portionwise and a dispersing agent. The process may be operated continuously or batchwise. "Degree of toughness" is defined as the number of creasing cycles which a film which has been maintained at 105 DEG C. for seven days, will withstand before breaking, the cycle consisting of creasing the film, turning the film through 180 DEG C. and creasing again. Reaction media mentioned are propane, butane, pentane, hexane, heptane, octane, decane, cyclopentane, cyclohexane, methylcyclohexane, 1,4-dimethylcyclohexane, cycloheptane, decahydronaphthalene, benzene, toluene, xylene, and petroleum fractions containing octanes. The dispersing agent may be the reaction product of polyethylene glycol with wool wax alcohols, long chain fatty acid diesters of polyethylene glycols and polypropylene glycols, silicone oils, alkylarylpolyoxymethylene glycol ethers, reaction products of hydrogenated rosin and olefin oxides, sodium oleate, lead stearate, or sodium caprylate. Specified catalysts are methyl, ethyl, butyl, octyl, dodecyl, octadecyl, dibutyl, ethyloctyl, tributyl, trihexyl, dimethyloctadecyl, didodecylmethyl, cyclohexyldibutyl, cyclohexyl, or diethylcyclohexylamine, aniline, toluidine, triethyl, tributyl, tritolyl, or trixylylphosphine, trinaphthyl or methyldioctylarsine, triethylstibine, hydrazine, morpholine, piperidines, N-alkylpiperidines, diphenylamine, and N,N-diethylaminoethanol. The polymers may be made into sheets, fibres, filaments, bristles, and films. Specification 748,836 is referred to.