Patent GB-664303-A (GB)
Title: Oleoresinous varnishes and methods for preparing them
Filed: 1949-07-19
Abstract: Oleoresinous varnishes of improved colour and drying properties are prepared by polymerizing at 60-100 DEG  F. a mixture of an oil-soluble varnish-maker's resin and an unsaturated glyceride drying oil containing a system of conjugated double bonds, in the presence of a volatile organic solvent and of a catalyst comprising a co-ordination complex of boron trifluoride and an organic compound having at least a pair of unshared electrons, this complex being present in an amount equivalent to 0.25-4.0 per cent by weight of boron fluoride based on the non-volatile content of the varnish. There are specified: varnish-maker's resin-oil-soluble natural resins, e.g. copals, dammars, rosin; synthetic resins, e.g. polyhydric alcohol-rosin esters, rosin-modified phenolic resins, or maleic resins, alkyd resins; unsaturated glyceride oils-chinawood, linseed; other oils may be added, e.g. oiticica, dehydrated castor oil, fish oils; solvents-toluene, xylene, petroleum naphthas, mineral spirits, dipentene, turpentine; catalysts-complexes of boron trifluoride with diethyl ether, dibutyl ether, phenyl methyl ether, phenol, acetone, methyl ethyl ketone, acetic acid; catalyst inactivator-calcium oxide and like alkali or alkaline earth oxides, hydroxides, or carbonates, which on addition form inert compounds with the boron trifluoride and thus arrest the reaction. In examples: (1) mixture of china-wood oil, rosin-modified phenol-formaldehyde resin dissolved in aromatic and aliphatic hydrocarbons, was heated with 7.5 parts borontrifluoride-diethyl ether complex, equivalent to 1.49 per cent boron trifluoride per weight of resin and oil, to 75 DEG  F., until the product had a viscosity of G-H; calcium oxide was then stirred into the mixture to check the reaction.  Other examples illustrate the use as the resin component of (2) phenol formaldehyde resin; (3) phenol formaldehyde resin and ester gum; (4) pentaerythritol ester gum.ALSO:Oleoresinous varnishes of improved colour and drying properties are prepared by polymerizing at 60-100 DEG F a mixture of an oil soluble varnish-maker's resin and an unsaturated glyceride drying oil containing a system of conjugated double bonds dissolved in a volatile solvent and in presence of a catalyst comprising a complex of boron trifluoride and an organic compound having at least a pair of unshared electrons, this complex being present in an amount equivalent to 0.25-4.0 per cent by weight of the boron trifluoride based on the non-volatile content of the varnish. There are specified: varnish-makers' resins-copals, dammars, rosin; unsaturated glyceride oils-chinawood, linseed; other oils may also be present, e.g. oiticica, dehydrated castor oil, fish oils; solvents-aromatic and aliphatic hydrocarbons, e.g. xylene, toluene, petroleum &c. naphthas, white spirits, dipentene, turpentine; catalysts-complexes of boron trifluoride with dietheyl ether, dibutyl ether, phenyl methyl ether, phenol, acetone methyl ethyl ketone, acetic acid; catalysts inactivator-calcium oxide and like alkali or alkaline earth oxides, hydroxides and carbonates, which on addition form inert compounds with the boron trifluoride and arrest the polymerization.  Compounds of lead and cobalt are added as driers. Tables and examples are given showing how the polymerization may be controlled to give varnishes having viscosities from A-T on the Gardner-Holdt scale.