| 摘要 |
A mixture comprising 2 to 6 compounds of compounds of the formula <FORM:1065516/C2/1> may be obtained by mixing the individual components or by condensing 1 mol. of stilbene -4,41-dicarboxylic acid in the presence of phosphorus trichloride or another acid halogenating agent with 2 mols. in total based on said acid, of 2 or 3 compounds of the formula <FORM:1065516/C2/2> wherein R, R1 and R2 are hydrogen or C1- 4 alkyl groups. In the examples, mixtures are prepared in which the radicals R1 and R2 are hydrogen, methyl, ethyl and tert-butyl groups.ALSO:An optical brightening agent for polyolefin fibres comprises a mixture of 2 to 6 compounds of the general formula: <FORM:1065516/D1-D2/1> wherein R1 and R2 are hydrogen or C1-4 alkyl groups. The mixture may be employed in an aqueous bath in a finely dispersed state in the presence of dispersing agents. The mixture may be employed in an amount of 0.005% to 0.5% based on the weight of the fibres. The fibre may be a polypropylene fibre which may be modified with a metallic organic or inorganic compound, e.g. aluminium stearate. |
