GB883070A - Modification of vinyl halide copolymers - Google Patents

Abstract

The invention comprises a partially saponified, partially unsaturated copolymer of 60-96% of a vinyl halide with a vinyl fatty acid ester, the vinyl halide component being dehydrohalogenated to produce a copolymer having an average unsaturation of at least 1,0 double bond per copolymer molecule and a corrected Iodine No. below 10 (e.g. 4-8), and the vinyl fatty acid ester component being converted to vinyl alcohol to an extent of 15-85%; the product preferably has a particle diameter less than 1,000 microns and contains less than 1% by weight of occluded salt. In a preferred embodiment, the product has a vinyl alcohol content of 2-10% and a particle diameter of 0,05-2,0 microns, while the starting material contains 82-92% of vinyl chloride. The copolymer of the invention may be admixed with a thermosetting resin which is a condensation product of an aldehyde with a material condensable therewith, e.g. a phenol, urea or melamine, the condensation having been effected in an alkaline medium. Solutions of the copolymer (or of its admixture with the said thermosetting resin) in organic solvents may be used to cast films or to prepare an adherent baked film coating on a metal base, e.g. iron, aluminium or tin. Aqueous dispersions of the copolymer may also be used for film formation. The solutions or dispersions may be coated on to paper or textiles and then cured to impart, e.g. grease resistance to the paper or textile treated.ALSO:The invention comprises a partially saponified, partially unsaturated copolymer of 60-96% of a vinyl halide with a vinyl fatty acid ester, the vinyl halide component being dehydrohalogenated to produce a copolymer having an average unsaturation of at least 1,0 double bond per copolymer molecule and a corrected Iodine No. below 10 (e.g. 4-8), and the vinyl fatty acid ester component being converted to vinyl alcohol to an extent of 15-85%; the product preferably has a particle diameter less than 1,000 microns and contains less than 1% by weight of occluded salt. The fatty acid from which the vinyl ester component is derived may be, e.g. formic, acetic, stearic, crotonic, eleostearic or ricinoleic acid. In a preferred embodiment, the product has a vinyl alcohol content of 2-10% and a particle diameter of 0,5-2,0 microns, while the starting material contains 82-92% of vinyl chloride; in Example 2, the starting material is a copolymer of 84,1% vinyl chloride, 15% of vinyl acetate and 0,9% of maleic acid. The partially saponified, partially unsaturated copolymer is prepared by forming a reaction mixture comprising a suspension of the copolymer in a liquid organic medium comprising a lower aliphatic alcohol and less than 5% by weight of water, and incorporating an alkali metal hydroxide or alcoholate, or a quaternary ammonium hydroxide or a mixture thereof, 0,018 to 0,18 mol pounds of the alkaline reagent being used per 100 pounds of copolymer, maintaining the mixture at 60-80 DEG C. to convert 15-85% of the vinyl ester to vinyl alcohol and washing to remove occluded salts. The copolymer of the invention may be admixed with a thermosetting resin which is a condensation product of an aldehyde with a material condensable therewith, e.g. a phenol, urea or melamine, the condensation having been effected in an alkaline medium. The copolymer of the invention may also be composited with (a) a vinyl chloride/vinyl acetate/maleic acid type copolymer, or, (b) unsaponified or acid hydrolyzed vinyl polymer and/or copolymer, e.g. the vinyl chloride/vinyl acetate copolymer starting material. Solutions of the copolymer (or of its admixture with the said thermosetting resin) in organic solvents may be used to cast films or to prepare an adherent baked film coating on a metal base. Aqueous dispersions of the copolymer may also be used for film formation. The solutions or dispersions may be coated on to paper or textiles and then cured to impart, e.g. grease resistance to the paper or textile treated. The coating composition may comprise solvents such as benzene, toluene, xylene, xylol or methyl ethyl ketone or, if a plastisol, plasticizers such as alkyl or alkoxy alkyl ricinoleates, phosphoric, sebacic, maleic or phthalic acid esters, e.g. with polyols such as glycerol and glycol. The composition may also comprise fillers and pigments such as silica, calcium carbonate, carbon black, barium sulphate, clay, alumina, bentonite, zinc or titanium oxides and surface active materials such as glycerol monolaurate, sodium oleate, sodium lauryl benzene sulphonate, lauryl ammonium acetate or carboxymethyl cellulose.