Patent GB-806906-A (GB)
Title: Copolymers of vinyl acetate and fumarate
IPC: C10M145/16
Filed: 1956-12-04
Abstract: Oil-soluble copolymers of vinyl acetate and a dialkyl fumarate mixture, wherein the mixture contains an average of 9 to 11 carbon atoms per alkyl group and the mixture consists essentially of (1) dialkyl fumarates having 8 carbon atoms in a branched chain in each alkyl group; and (2) dialkyl fumarates having 14 to 18 carbon atoms in a straight chain in each alkyl group (see Group IV (a)), may be added to lubricating oils in amounts from 0.05 to 10 per cent by weight, as viscosity index improvers or as pour depressers.  Oil base-stocks specified are paraffinic oils and naphthenic or mixed base lubricating oils.  The copolymers may also be added to greases containing metal soaps, to paraffin wax or waxy compositions or to light liquid hydrocarbon oils, e.g. diesel fuel base-stocks, domestic heating oil base-stocks, mineral seal oil and refined kerosene. Other additives, e.g. dyes, antioxidants, other depressors such as wax-naphthalene and wax-phenol condensation products, and other viscosity index improvers such as polybutylene, polylauryl methacrylate, polyvinyl ethers and polyvinyl esters, may also be added.  Additive concentrates may be made consisting of a mineral lubricating oil and 10 to 50 per cent by weight of the copolymer, with or without detergents, e.g. barium t-butylphenol sulphide and oxidation inhibitors, e.g. phenyl a -naphthylamine.  Examples are given comparing the pour depressant activity and viscosity index improvement potency of the novel copolymers with known copolymers. Specification 635,903 is referred to.ALSO:The invention comprises an oil-soluble copolymer of vinyl acetate and a dialkyl fumarate mixture wherein the fumarate mixture contains an average of 9 to 11 C atoms per alkyl group and the mixture consists essentially of (1) dialkyl fumarates having 8 C atoms in a branched chain in each alkyl group and (2) dialkyl fumarates having 14 to 18 C atoms in a straight-chain in each alkyl group.  In making the copolymer, each of the two dialkyl fumarates is preferably formed separately (see Group IV (b)) and subsequently mixed prior to polymerization, the vinyl acetate preferably being added gradually to the fumarate mixture; the fumarate mixture and vinyl acetate are mixed, e.g. in the molar ratio from 2 : 1 to 1 : 3 and heated to a temperature of 40 DEG  to 100 DEG C., with or without a solvent or diluent, e.g. n-heptane, petroleum ether, naphtha, kerosene or lubricating oil, preferably in the presence of a catalyst, e.g. benzoyl peroxide, acetyl peroxide, t-butylhydroperoxide, or t-butyl perbenzoate, preferably in an oxygen-free atmosphere, e.g. nitrogen or carbon dioxide, and, if necessary, under superatmospheric pressure or refluxing conditions. One example of preparing the novel copolymer and several preparations of comparative copolymers are given.  Uses.-For improving the pour point and viscosity index of oils. Specification 635,903 is referred to.ALSO:C8 branched-chain dialkyl fumarates and C14-C18 straight-chain dialkyl fumarates are made by direct esterification of fumaric acid with a branched chain C8 alcohol and C14-C18 straight-chain alcohols respectively, if desired, in the presence of esterification catalysts, e.g. sulphuric acid, and toluene sulphonic acid, and water entrainers.  In the example, C8 oxo alcohol and hydrogenated tallow alcohol were used to make the respective dialkyl fumarates.  In a comparative experiment, fumaric acid is similarly di-esterified with coconut alcohols comprising C8-C18 straight-chain normal alcohols.