Optically brightened plastics for optically brightening paper-coating compounds and paper-coating compounds optically brightened in this manner
AssigneeBayer Aktiengesellschaft
InventorsUdo Eckstein, Joachim König, Fritz Puchner, Ulrich Feldhues, Matthias Köcher, Uwe Vogt, Eckhard Wenderoth
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Abstract
Paper coating slips having high whiteness, high greying limit and high lightfastness can be prepared with the aid of whitened finely divided plastics.
Claims2
A method for whitening a paper coating slip based on synthetic binders which comprises incorporating into said coating slip a whitened polyacrylonitrile powder having a weight-average particle size of less than 1 μm, or an aqueous suspension of said whitened polyacrylonitrile powder, wherein said polyacrylonitrile powder is whitened with a whitener selected from the group consisting of
- in which
- X represents CH or N,
- R1 represents CH3 or CH2—C6H5 and
- R2 represents H or SO2—CH3;
- and
- in which
- R3 denotes NH2, CH3, NH—C3H6—N(CH3)3+An−, C2H4—N(CH3)3+An−, CH2—CH(CH3)—N(CH3)3+An−, CH(CH3)—CH2—N(CH3)3+An−, C2H4O—CH(CH3)—CH2—N(CH3)3+An− or C2H4—CO—NH—C3H6—N(CH3)3+An− and
- An⊖ denotes the anion of a mineral acid, formic acid, acetic acid, lactic acid or O3SOCH3.
A paper coating slip based on synthetic binders which comprises a whitened polyacrylonitrile powder having a weight-average particle size of less than 1 μm, or an aqueous suspension of said whitened polyacrylonitrile powder, wherein said polyacrylonitrile powder is whitened with a whitener selected from the group consisting of
- in which
- X represents CH or N,
- R1 represents CH3 or CH2—C6H5 and
- R2 represents H or SO2—CH3;
- and
- in which
- R3 denotes NH2, CH3, NH—C3H6—N(CH3)3+An−, C2H4—N(CH3)3+An−, CH2—CH(CH3)—N(CH3)3+An−, CH(CH3)—CH2—N(CH3)3+An−, C2H4—O—CH(CH3)—CH2—N(CH3)3+ An− or C2H4—CO—NH—C3H6—N(CH3)3+An− and
- An⊖ denotes the anion of a mineral acid, formic acid, acetic acid, lactic acid or O3SOCH3.
Dependencies are inferred from the claim text.