STABLE LATEX GELLANT SYSTEM AND ITS USE IN THE PRODUCTION OF VULCANIZED LATEX FOAM

摘要

1509356 Foam coatings GOODYEAR TIRE & RUBBER CO 3 May 1976 [14 May 1975] 17978/76 Heading B2E [Also in Division C3] A textile substrate for use in carpet underlays or cushioning is coated with a rubber latex foam which has been gelled with a heat sensitive stable gellant system comprising (A) an amphoteric surfactant acid and/or alkali metal salt thereof (i.e. a surfactant which behaves as a cationic surfactant in acid media and as an anionic surfactant in alkaline media), (B) a non - amphoteric water solube acid which is soluble to the extent of at least 10g/100g water at 25‹C and has a pH dissociation content of 5 or less at 25‹C and (c) a water soluble volatile base which is soluble to the extent of at least 5.5g/100g water at 20‹C and has a l.p. of -33 to 180‹C at 760mm, in sufficient amount to result in a pH of 8-12 in the gellant system when (A), (B) and (C) have been brought together in aq. solution. The coated substrates are made by adding the gellant system to a rubber latex, emulsified with one or more fatty acid or rosin acid soaps, prior to the addition of vulcanization agents, frothing the latex, spreading the foam on a textile substrate and drying and vulcanizing the foam to produce the coated substrate. The surfactant (A) may be N - coco - # - aminopropionic acid, N - lauryl myristyl - # - aminopropionic acid, sodium N - coco - # - aminopropionate, disodium N - lauryl - # - aminodipropionate or the partial sodium salt of N - lauryl - # - iminodipropionic acid. The acid (B) may be sulphuric, hydrochloric, phosphoric, acetic, p - toluene sulphonic or sulphonic acid. The base (C) may be ammonia mono- or dimethylamine, mono- or di-ethylamine, monoethanolamine or morpholine. n the example (1) an SBR rubber latex was combined with the above gellant and (A) potassium oleate, tetrapotassium pyrophosphate, ammonic, styrene/maleic anhydride resin neutralized with ammonia, feldspar, hydrated alumina and water and also (B) a phenolic antioxidant zinc oxide, sulphur, zinc diethyldithiocarbamate and zinc 2 - mercaptobenzothiazole and the composition was mixed, frothed with air in a mixer, spread on a jute substrate, set in a radiant heat chamber and dried and cured in a hot air oven to provide a carpet underlay.