Improvements in or relating to the production of surface-coated papers using brightening agents

摘要

The brightness of white surface-coated paper is enhanced by incorporating in the paper support or in one or more surface coatings thereof or in both an anionic fluorescent compound or compounds and poly(vinyl-2-oxazolidone). The fluorescent compound may be an amino-stilbene of the general formula FORM:0967892/C4-C5/1 where Q and Q1 are each FORM:0967892/C4-C5/2 or R5-CO-, R3, R4 and R5 are each hydrogen, halogen, hydroxyl, amino or any of a wide variety of organic radicals linked directly or through O, N or S (examples given in the Specification) and may be the same or different from one another and R1 and R2 are each a water-solubilizin group, e.g. sulpho or carboxyl or a salt thereof, or if at least one of the groups R3, R4 and R5 is anionic may be hydrogen. The fluorescent compound and the poly(vinyl-2-oxazolidone) may be incorporated separately or may first be reacted to form an addition compound which is then incorporated. In the former case they may be present in the same layer or in different layers of the coated paper, or paper, e.g. a photographic paper, having poly(vinyl-2-oxazolidone) incorporated in it or in a coating layer, may be treated with a solution, e.g. a developing, stop or fixing bath, containing the fluorescent compound. The paper support or the coating or both may also include poly(vinylpyrrolidone) or a copolymer of vinylpyrrolidone and vinyl acetate or both. Specification 884,736 also is referred to.ALSO:The brightness of white surface-coated paper is enhanced by incorporating in the paper support or in one or more surface coatings thereof or in both an anionic fluorescent compound or compounds and poly(vinyl-2-oxazolidone). The fluorescent compound may be an amino-stilbene of the general formula: FORM:0967892/D1-D2/1 where Q and Q1 are each FORM:0967892/D1-D2/2 or R5 -CO-, R3, R4 and R5 are each hydrogen, halogen, hydroxyl, amino or any of a wide variety of organic radicals linked directly or through O, N or S, (examples given in the Specification) and may be the same or different from one another and R1 and R2 are each a water-solubilizing group, e.g. sulpho or carboxyl or a salt thereof, or if at least one of the groups R3, R4 and R5 is anionic may be hydrogen. The fluorescent compound and the poly(vinyl-2-oxazolidone) may be incorporated separately or may first be reacted to form an addition compound which is then incorporated. In the former case they may be present in the same layer or in different layers of the coated paper, or paper, e.g. a photographic paper, having poly(vinyl-2-oxagolidone) incorporated in it or in a coating layer, may be treated with a solution, e.g. a developing, stop or fixing bath, containing the fluorescent compound. The paper support or the coating or both may also include polyvinylpyrrolidone or a copolymer of vinylpyrrolidone and the vinyl acetate or both. Specification 884,736 also is referred to.