The product is readily soluble in water, acid-resistant, alkali-resistant, and has much better whitening effect than VBL at pH 4.5-7. Belonging to anionic type, it can be used in the one bath with anionic or nonionic surfactants. APPLICATION: Mainly applied to whiten paper pulp, surface sizing, coating, and also applied to whiten cotton, linen and cellulose fiber as well as cellulose fabrics, and to brighten light-colored cellulose fabrics.