# US 7,608,168 B2 · Alkanolammonium-containing triazinyl flavonate whiteners

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- Number: US 7,608,168 B2
- Document ID: US7608168B2
- Status: Granted
- Kind: B2
- Application number: 11/187,735
- Filed: 2005-07-22
- Published: 2006-03-30
- Granted: 2009-10-27
- Earliest claimed: 2004-08-06
- Assignees: Kemira Oyj
- Inventors: Heinz Giesecke; Bernhard Hunke
- Web page: https://patentgrep.com/patent/US7608168B2

## CPC

- D21H 21/30: Luminescent or fluorescent substances, e.g. for optical bleaching (D21H21/40 takes precedence)
- D21H 17/28: Starch
- D21H 21/16: Sizing or water-repelling agents
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR

## Abstract

A process for whitening paper in a size press includes contacting a cellulose sheet with a size press liquor that contains a surface size and a particular whitener containing sulfonate groups and cations, M, wherein at least 10% of all cations M have the formula in which R5 to R7, independently of one another, denote hydrogen, a C1-C4-alkyl radical or an optionally further substituted C2-C4-hydroxyalkyl radical, and R8 denotes an optionally further substituted C2-C4-hydroxyalkyl radical. The process provides superior paper whitening compared to a corresponding process in which the whitener cations are all sodium or potassium ions.

## Claims

### Claim 1

A process for whitening paper in the size press, comprising contacting a cellulose sheet with a size press liquor, wherein the size press liquor consists essentially of
(a) a whitener of the formula Ia
in which
M denotes a mixture containing the cation of the formula II
and Na+ or K+, and
at least 10 mol % of all cations M correspond to the formula II;
(b) water,
(c) surface size, and
(d) optionally, starch, carrier substances, salts, standardizing agents, and/or auxiliaries.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the size press liquor contains whiteners which comprise more than 50% by weight of a whitener of the formula Ia.

### Claim 3 (depends on 1)

The process according to claim 1, and comprising the starch, wherein the starch is natural, derivatized, or degraded starch.

### Claim 4 (depends on 3)

The process according to claim 3, wherein the starch is oxidatively degraded starch.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the size press liquor comprises the whitener of the formula Ia in an amount of less than 2.5% by weight.

### Claim 6 (depends on 1)

The process according to claim 1, wherein the size press liquor comprises the whitener of the formula Ia in an amount of 0.01 to 2.0% by weight.

### Claim 7 (depends on 1)

The process according to claim 1, wherein at least 20 mol % of all cations M correspond to the formula II.

### Claim 8 (depends on 1)

The process according to claim 1, wherein at least 50 mol % of all cations M correspond to the formula II.

### Claim 9 (depends on 1)

The process according to claim 1, wherein at least 80 mol % of all cations M correspond to the formula II.

### Claim 10 (depends on 1)

The process according to claim 1, wherein, in Formula Ia, the terminal sulfo groups are each in the para position relative to the aniline nitrogen atom,
50 to 100 mol % of all cations M correspond to the formula II;
and
wherein the size press liquor comprises the whitener of the formula Ia in an amount of 0.5 to 2.0% by weight.

### Claim 11

A size press liquor consisting essentially of:
(a) a whitener of the formula Ia
in which
M denotes a mixture containing the cation of the formula II
and Na+ or K+, and
at least 10 mol % of all cations M correspond to the formula II;
(b) water,
(c) surface size, and
(d) optionally, starch, carrier substances, salts, standardizing agents, and/or auxiliaries.