| 摘要 |
A composition for whitening paper comprises a concentrated aqueous solution, adapted to be diluted with water, containing 10%-35% by weight of a fluorescent brightening agent of the formula <FORM:0890420/IV (c)/1> in which X is hydrogen or an alkali metal and at least sufficient of one alkylolamine of the formula (HO-alk)x-NR(3-x), in which alk is an alkylene radical of 2-4 carbon atoms, R is hydrogen or an alkyl radical of 1-8 carbon atoms and x is an integer of 1-3, to effect dissolution of the fluorescent brightening agent in water, the composition being free of or containing not more than 1% by weight of sodium chloride. Specified alkylolamines are mono-, di- and triethanolamines and the corresponding propanolamines and butanolamines, N-methyl diethanolamine, N,N-dimethyl ethanolamine, N,N-diethylethanolamine, N,N-di-isopropyl ethanolamine and N,N-di(2-ethylhexyl) ethanolamine. The proportion by weight of alkylolamine to fluorescent brightening agent may be from 0.5 : 1 to 3.5 : 1 and the solution preferably contains 5%-35% by weight of the alkylolamine. The composition may also contain soda ash, borax, tetrasodium pyrophosphate and lower alkyl ethers of ethylene glycol. In use the solution may be diluted to a concentration of fluorescent brightening agent of about 0.5%-0.1% by weight and sheets of paper immersed in the solution, freed of excess water and dried. |
