GB1114579A - Inks for ball point pens - Google Patents

Abstract

A ball-point pen ink comprises a solution in a high boiling point organic solvent of a coloured copolymer which has been prepared from: (a) an aromatic monoethylenically unsaturated compound and/or (b) an ester of a monoethylenically unsaturated carboxylic acid and (c) a dye bearing an ethylenically unsaturated group, by copolymerization of (a) and/or (b) and (c) component (c) may be replaced by: (c) a monoethylenically unsaturated monomer bearing a reactive group and the copolymer obtained is reacted with: (f) a dye bearing a reactive group complementary to the reactive group borne by component (e). In another modification, component (c) is replaced by: (g) a monoethylinecally unsaturated diazotizable monomer and the copolymer obtained is diazotized and then reacted with (h) a coupling component, to form a polymer dye. The coloured copolymer may contain units of (d) one or more further monomers. The high boiling points solvent has a boiling point of not less than 125 DEG C., those specified being 1,2-propylene carbonate, dicyclohexyl carbonate, diphenyl carbonate, adipate and phthalic esters such as diethyl or di-n-butyl phthalate, methyl glycol, ethyl glycol and benzyl alcohol. Monomer (a) is e.g. styrene or a substituted styrene, for instance p-methyl, p-chloro, o-chloro or p-hydroxystyrene. Specified monomers (b) include ethyl, n-butyl, cyclohexyl, 2-ethylhexyl and stearylacrylates, and methylmethacrylate. Suitable dyes (c) are azo, anthraquinone or triphenylmethane dyes containing a vinyl, acrylyl, acrylylamino, acryloyloxyalkyl or acrylyloxyaryl group. Component (e) may be acrylamide, methacrylamide or a derivative thereof and component (g) may be p-aminostyrene. In the examples, ethyl acrylate or methyl methacrylate are copolymerized with a dye of formula <FORM:1114579/C3/1> in solution in n-butyl acetate using azodiisobutyrodinitril as catalyst. Benzyl alcohol is added to the resulting solution, from which the butyl acetate is then removed by distillation, to yield a red ink. When methyl methacrylate is similarly copolymerized with a dye of formula <FORM:1114579/C3/2> an orange-red ink is obtained, with a dye of formula <FORM:1114579/C3/3> a yellow ink is obtained and with a dye of formula <FORM:1114579/C3/4> a violet ink is obtained.