GB942188A - Polymers of use in photography - Google Patents

Abstract

Polymers comprise recurring units of four kinds represented by formulae A, B, C, D: <FORM:0942188/C3/1> wherein n is an integer from 1 to 5; R is H, a C1- 12 alkyl group or a phenyl- or tolyl-substituted C1- 4 alkyl group; and R1 is H or CH3. The invention relates to such polymers which neutralise 4 to 6 ml. N NaOH per gm. They may be prepared by heating, in the presence of a strong acid catalyst and water, a fluid mixture comprising (i) 15 to 30% of a copolymer of vinyl alcohol or a carboxylic acid ester thereof with maleic, citraconic, dimethylmaleic, fumaric, mesaconic or dimethylfumaric acid, anhydride or C1- 4 alkyl ester; (ii) 35 to 65% of a monohydroxy carboxylic acid (CnH2n) (OH) (COOH) or (CnH2n- 1)(OH)(COOH)2; and (iii) 10 to 45% of an alcohol ROH, the percentages being by weight of the total of (i), (ii) and (iii) and R and n being as defined above. The vinyl ester in (i) may be the acetate, propionate or benzoate. The strong acid may be sulphuric or hydrochloric. The reaction can take place at 60 to 100 DEG C. in an organic media. The copolymer may be reacted with a hydroxylated material which has another hydrophilic group e.g. amide or sulphonic acid. Modifying agents such as drying, non-drying, and semi-drying oils; natural or synthetic resins, waxes and cellulose derivatives may be added to the products. Details are given of the preparation of vinyl acetate-maleic anhydride copolymers using benzoyl peroxide as catalyst, (a) in bulk followed by purification by dissolution in acetone and precipitation in water, and (b) in benzene. The copolymers are heated in the presence of sulphuric acid with lactic or glycolic acid and a variety of alcohols, including benzylalcohol. The presence of water is achieved either by using aqueous glycolic acid or moist polymer. Applications. The products can be dissolved in organic solvents e.g. dioxane; mixtures thereof with ethanol, methanol and butanol; ketones such as acetone; ethylene chloride; and alkyl ethers of ethylene glycol- and cast into films on a glass or metal plate or smooth revolving drum, or used to form coatings. The polymers are particularly useful for photographic materials and may be used as the carrier for light-sensitive materials, as a support for light sensitive coatings, as a stripping interlayer or as an antihalation backing layer, in which case they may contain a dye or pigment such as carbon black. Specification 537,709 is referred to.