Method for increasing brightness retention of laundered fabrics
US6413925B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 2001 |
| Grant date | Jul 2, 2002 |
| Priority date | — |
| Expiry date | Jan 16, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC11D2111/12
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The invention provides a method for increasing the brightness retention of a laundered fabric after numerous washing cycles by adding to an aqueous wash liquor a quantity of a commercial laundry detergent which delivers at least 0.1 g of an optical brightener into said wash liquor, said optical brightener exhibiting instability in the presence of hypochlorite; and prior to, concurrent with, or after the commercial laundry detergent, adding a bleaching composition in an amount of at least about 0.5 g/L. The bleaching composition contains about 2.5-10% alkali metal hypochlorite; about 0.05-5% of a bleach stable surfactant bearing at least one nitrogen atom; a bleach stable anionic surfactant or a hydrotrope, wherein the ratio of (ii) to (iii) is between about 10:1 to about 1:10; and an effective amount of a source of alkalinity. The fabric is repeatedly washed and the optical brightener is enabled to deposit on the fabric to increase versus a control a Stensby whiteness measure of at least about &Dgr;W=4.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.