GB820930A - Improvements in or relating to polymeric material - Google Patents

Abstract

Polymeric material is made by (1) polymerizing one or more ethylenically unsaturated monomers or (2) forming an "aminoplastic" or a "phenoplast" in the presence of an aqueous colloidal dispersion of a "vinylic filler" and interrupting if necessary the polymerization or condensation before any substantial amount of cross-linking occurs. The expression "vinylic filler" is defined in the parent Specification. By "vinylic filler" is meant the homopolymerization and multipolymerization products in the form of substantially rigid particles obtainable from polymerizable substance containing unsatured linkages providing the products therefrom are cross-linked within the particles to a condition of substantially complete insolubility in organic solvents. The product of the process may be a "graft" polymer. A very extensive list of "vinylic fillers" is given in the Specification. Exemplified "vinylic fillers" are copolymers of styrene, divinylbenzene, and 4-vinylpyridine, or methacrylic acid. The polymerization of the ethylenically unsaturated monomers is generally effected in the presence of a catalyst, e.g. a redox system, and an additional emulsifier such as tallow soap, hydrogenated tallow soap, rosin soaps, alkyl aryl sulphonates, alkyl sulphates, dodecylamine hydrochloride, and polymeric emulsifiers of the type exemplified in the parent Specification. The catalyst may be potassium or ammonium persulphate, sodium perborate, sodium perchlorate, hydrogen peroxide, benzoyl or acetyl peroxides, cumene hydroperoxide, or diisopropylbenzene hydroperoxide alone or in admixture with salts of iron, cobalt, sodium or potassium pyrophosphate, or sodium sulphite. Azo bis-(isobutyronitrile) may also be used as the catalyst. The term "phenoplasts" is used in the manner defined by T. S. Carswell in his book entitled Phenoplasts, their Structure, Properties and Chemical Technology, and the term "aminoplastics" in the manner defined by C. P. Vale in his book entitled Aminoplastics. The phenoplast may be made by condensing phenol or a substituted phenol such as cresol, xylenol, or resorcinol, with formaldehyde, glyoxal, or furfural, in the presence of an acid or basic catalyst. The aminoplastic may be made by condensing urea, melamine, thiourea, or quanidine with formaldehyde or glyoxal. The monomers polymerized in the presence of the vinyl filler may be butadiene, 4-vinylpyridine, methylmethacrylate, styrene, methacrolein, or mixtures thereof. In an example, urea is condensed with formaldehyde in the presence of ammonia and sodium hydroxide, and a "vinylic filler" consisting of a cross-linked copolymer of styrene, divinyl benzene and pyridine.