STORAGE STABLE SOLUTIONS OF OPTICAL BRIGHTENERS

• US 20100294447A1
• Filed: 12/09/2008
• Published: 11/25/2010
• Est. Priority Date: 12/12/2007
• Status: Active Grant

• Current Assignee: Archroma IP GmbH
• Original Assignee: Clariant Finance (Bvi) Limited
• Inventors: Jackson, Andrew Clive, Oberholzer, Martin, Mahon, Margaret, Farrar, John Martin
• Granted Patent: US 8,894,815 B2
• Time in Patent Office: Days
• US Class Current: 162/158
• CPC Class Codes: C07D 251/68 Triazinylamino stilbenes
• CPC Class Codes: C08K 5/0041 Optical brightening agents, organic pigments
• CPC Class Codes: C08K 5/0091 Complexes with metal-heteroatom-bonds

Abstract

The instant invention relates to storage stable solutions of optical brighteners based on certain salt forms of anilino-substituted bistriazinyl derivatives of 4,4′-diaminostilbene-2,2′-disulphonic acid and of organic acids which do not need extra solubilising additives.

Claims

1. An aqueous solution containing 10 to 40% by weight of a compound of formula (1)

2. An aqueous solution according to claim 1, containing 15 to 35% by weight of a compound of formula (1) and wherein

R is hydrogen or a methyl radical,

M⁺ is Na⁺, and

n is less than or equal to 1.5, and

of 0.1 to 2% by weight of citric acid.

3. A aqueous solution according to claim 2, wherein

R is hydrogen,

M⁺ is Na⁺, and

n is less than or equal to 1.5.

4. An aqueous solution according to claim 2, wherein

R is hydrogen,

M⁺ is Na⁺, and

n is less than or equal to 1.2.

5. An aqueous solution according to claim 1, further comprising one or more carriers, antifreezes, defoamers, solubilizing aids, preservatives or complexing agents, and organic by-products formed during the preparation of an optical brightener.

6. A process for preparing an aqueous solution according to claim 1, comprising the step of converting a compound of formula (2)

7. An optical brightener for textiles, paper, board and non-wovens comprising an aqueous solution as claimed in claim 1.

8. An aqueous suspension of pulp comprising an aqueous solution as claimed in claim 1.

9. A process for whitening of paper comprising the steps of

providing a pulp suspension,

adding 0.01 to 2% by weight based on dry fibre of an aqueous solution according to claim 1,

producing a paper sheet from the pulp suspension,

pressing and drying the paper sheet.

10. A process for whitening of paper comprising the steps of

preparing an aqueous coating composition by mixing together chalk or other white pigments, one or more dispersing agents, a primary latex binder and optionally a secondary binder, and optionally other additives,

adding 0.01 to 3% by weight based on dry pigment of an aqueous solution according to claim 1,

applying the coating composition to a paper sheet to form a coated paper sheet,

drying the coated paper sheet.