Patent GB-704607-A (GB)
Title: Improvements in or relating to the preparation of synthetic drying oils and coating compositions therefrom
IPC: C08F236/10
Filed: 1950-05-26
Abstract: Drying oil copolymers are made by copolymerizing a mixture comprising 60 to 90 per cent. of a conjugated diolefine containing from 4 to 6 carbon atoms per molecule such as butadiene-1,3, isoprene, dimethyl butadiene-1,3, piperylene and methyl pentadiene, and from 40 to 10 per cent. of styrene or a nuclearly hydrocarbon-substituted styrene such as paramethylstyrene, dimethyl styrene, and diethyl styrene, in the presence as a catalyst of finely divided sodium or potassium or mixtures or alloys of these metals which are solid above 20 DEG  C., the reaction being carried out in a diluent at a temperature above 20 DEG  C. but below the melting point of the catalyst.  Suitable diluents are mineral spirits, xylene, benzene, toluene, cyclohexane, diethyl ether, diisopropyl ether, dioxane, vinyl ethyl ether, vinyl isopropyl ether, vinyl isobutyl ether, anisole, phenetole, and diluents such as butane-2 or other low boiling olefines which modify the reaction by limited copolymerization and chain termination.  The reaction mixture may also contain a C1 to C5 aliphatic alcohol such as isopropanol or tertiary butanol which acts as a polymerization promoter.  At the end of the reaction the catalyst is destroyed with excess of an alcohol, the reaction mixture then being neutralized and filtered.  The unmodified copolymers so produced have molecular weights of 2,000 to 3,000 and may be heat bodied by heating at 200 DEG  to 300 DEG  C.  The solution of copolymer in the reaction diluent may be used as a varnish or the copolymer may be modified by reaction with a monoethylenically unsaturated compound containing non-hydrocarbon elements or groups whose ethylenic linkage is capable of reacting with the methylene groups adjacent to the double bonds in the copolymer, such as maleic, chlormaleic, and citraconic acids and anhydrides, acrylonitrile, methacrylonitrile, chloroacrylonitrile, methyl acrylate, butyl acrylate, methyl methacrylate, vinyl acetate, vinyl methyl ketone, and cinnamaldehyde, or with a compound containing a thiol group capable of reacting with the double bonds of the copolymer such as thioglycollic acid, mercaptopropionic acid, thiosalicylic acid, and the corresponding anhydrides, esters, aldehydes and ketones. The reaction between the copolymer and a monoethylenically unsaturated monomer may be accelerated by a peroxide catalyst such as benzoyl peroxide, tert.-butyl hydroperoxide, peracetic acid, and cumene hydroperoxide.  The drying oil copolymers may be dissolved in drying oils to produce a varnish, paint, or enamel base, or they may be employed as additions to drying or semi-drying oils such as linseed, soybean, rapeseed, tung, cottonseed, perilla, oiticia, corn, dehydrated castor, sunflower and safflower oils, in order to improve the cooking rate thereof. This improvement in cooking rate may also be applied to oleoresinous varnishes containing a drying oil and a resin such as ester gum, oil soluble hydrocarbon resins such as the reaction product of butadiene and benzene, straight and modified phenol aldehyde resins, maleic anhydride treated rosins and esters, and natural resins.  Coating compositions may be prepared from the modified and unmodified copolymers containing pigments such as titanium dioxide, chrome green, chrome yellows, carbon black, red lead, toluidine and lithol red, iron and phthalocyanine blues, and hansa yellows, solvents such as xylene, naphthas, mixed aromatics, white oils and solvents known under the Registered Trade Mark "Solvesso," driers such as lead cobalt and manganese naphthenates, and heavy metal soaps of octanoic, stearic, and oleic acids such as copper octoate, cobalt stearate, and manganese oleate, and calcium oxide as a stabilizer for the siccative properties of the oils.ALSO:The cooking rate of drying or semi-drying vegetable oils is accelerated by adding thereto an oily copolymer of a conjugated diolefine containing 4 to 6 carbon atoms per molecule and styrene or a nuclearly hydrocarbon substituted styrene (see Group IV (a)) and cooking the mixture at 230 DEG  to 330 DEG C. until the cooked oil has reached the desired consistency.  Drying oils specified are linseed, soyabean, rapeseed, tung, cottonseed, perilla, oiticica, corn, dehydrated castor, sunflower seed, and safflower oils.  In carrying out the process an excess of either drying oil or copolymer may be used.  The process may also be applied to accelerating the cooking rate of mixtures of drying oils and natural or synthetic resins.