Patent GB-781185-A (GB)
Title: Improvements in or relating to artificial fibres and films and processes for their production
IPC: C08F220/44
Filed: 1954-08-06
Abstract: A composition comprises a solution of a substantially saturated linear fibre- and/or film-forming polymer and a microsol which is a stable dispersion or suspension of d-microgel particles in a liquid extending medium which does not dissolve the particles but which causes them to swell, the d-microgel consisting of unimolecular colloidal particles of cross-linked polymer having an average diameter no greater than about 3 microns, the microsol having a liquid common to or miscible with the solvent of the solution as its extending medium, the concentration of microgel in the composition being no greater than its gel point, the gel point being the concentration of a given microgel particle in a given extending medium at which the medium is absorbed by the particles.  The microgels may be prepared (1) by copolymerization of monomers such as styrene, ethylene, propylene, butylene, butadiene, isoprene, chloroprene, vinyl and vinylidene chlorides, chlortrifluoroethylene, vinyl acetate, acrylic acid, methyl and ethyl acrylates and methacrylates, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, salts and amides of acrylic acid and its derivatives and vinylidene cyanide with cross-linking monomers, such as divinyl benzene, ethylene bisacrylamide, ethylene bis-acrylate and -methacrylate, triethylene dimethacrylate, vinyl acrylate, glycol divinyl and glycerol trivinyl ethers, diallyl cyanamide, benzene diallyl phosphonate and divinyl benzenesulphonic acid.  The copolymers may also contain units of other monomers conferring dye-receptive or flame-proofing properties such as methallyl sulphonic acid, propene-2-phosphonic acid, styrene-4-sulphonic acid, vinyl pyridine, vinyloxyethylamine, vinyl halides and phosphorus containing monomers.  In Examples (1-16 and 33) the preparation of cross-linked copolymers in aqueous emulsions containing sodium lauryl sulphate is described, azo and redox catalysts being employed.  In Example (16) a vinyl acetate copolymer is hydrolysed with sulphuric acid.  (2) By a condensation reaction which is preferably carried out by an emulsion process in which each reactant is dissolved in a different immiscible solvent, suitable reactants in one phase are compounds having two or more amino, hydroxyl and/or mercapto groups while the other phase contains a compound such as phosgene, a polycarboxylic halide or anhydride, glycol chloroformates, polyisocyanates, polythio-isocyanates and polysulphonic acid halides; in an Example (17) adipyl chloride and hexamethylene diamine are condensed in this manner using a mixture of triethylene tetramine and 2,5,8-tris-(aminoethyl) nonane as a cross-linking agent; or (3) by reacting a preformed linear polymer with a polyunsaturated monomer; in an Example (18) acrylonitrile is emulsion polymerized and then subjected to further polymerization in the presence of ethylene bismethacrylate.  The microgel is incorporated in the linear polymer in the presence of a solvent which is a solvent for the polymer and also an extending medium for microsol formation. Linear polymers and liquids specified are polyacrylonitrile/dimethyl formamide, cellulose acetate/acetone, cellulose triacetate/chloroform, a condensation product of diphenylol propane, isophthaloyl chloride and terephthaloyl chloride/methylene chloride, polyethylene-1,4-piperazine dicarboxylate (Example 29)/chloroform and methanol and cellulose xanthate/water; other linear polymers specified are cellulose, cellulose butyrate, methyl cellulose and ethyl cellulose, those derived from ethylene, propylene, isobutylene, vinyl and vinylidene chlorides, vinyl acetate, vinylidene cyanide, methyl acrylate and methacrylate and acrylamide and polymers obtained from the condensation of terephthalic, adipic or sebacic acid with hexamethylene diamine, caprolactam, terephthalic acid and ethylene glycol and hexamethylene diisocyanate with 1,4-butene diol or hexamethylene diamine and natural polymers such as casein and zein. The compositions are formed by conventional methods into artificial filaments and films, the properties of which may be varied by varying the amount and nature of the microgel present.  Examples are furnished of the production of filaments from the compositions by conventional dry and wet spinning methods and of films by conventional casting methods. Specification 712,950 is referred to.