| 摘要 |
<p>Sequestering agents for use as a whitening and fabric strength enhancer for aqueous hypochlorite bleach compositions are provided. It was found that the sequesterants when used with hypochlorite in the presence of soluble heavy metal ions, particularly iron and manganese ions, provide significantly improved whitening and fabric protection. Most preferably, the sequesterants are selected from polyacrylic acid, a polyacrylic acid derivative, a copolymer of acrylic acid or methacrylic acid and a comonomer which is maleic acid or maleic anhydride and mixtures thereof. In one aspect, the sequesterants are employed in a method for laundering fabrics comprising: a) providing, in a wash liquor containing (i) at least about 40 ppb of iron cations or (ii) at least about 10 ppb of manganese cations, or (iii) the cations of both (i) and (ii), and a fabric piece; and b) adding either prior to, contemporaneously with, or after, the step of providing of said fabric piece to said wash liquor a hypochlorite composition which comprises one or more of said sequesterants. Preferably the sequesterant comprises at least 0.1 ppm by weight of said wash liquor and the hypochlorite composition is an alkali metal hypochlorite and said sequesterant has a molecular weight of between about 500 and 500,000 daltons.</p> |
