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US 5,482,514 AGranted
Process for enhancing the whiteness, brightness and chormaticity of paper making fibres
AssigneeCiba-Geigy Corporation
InventorAxel von Raven
Life of this patent
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Abstract
The present invention relates to the addition of photosensitising compounds to woodpulps and mixtures thereof for enhancing their whiteness, brightness and chromaticity, as well as to the paper making fibres so obtained and the use thereof.
Claims17
A process for enhancing the whiteness, brightness and chromaticity of paper-making fibers, which comprises mixing water, paper-making fibers and a photoactivator to form an aqueous suspension, wherein said photoactivator is one or more than one water-soluble phthalocyanine complex of the formula (1) ##STR3## wherein
- MePc is a manganese, zinc or aluminum phthalocyanine ring system,
- Y is hydrogen, an alkali metal or ammonium,
- v is any number from 1 to 4,
- R is fluorine, chlorine, bromine or iodine, and
- x is any number from 0 to 8.
2 more elements
Dependencies are inferred from the claim text.