Method of brightness enhancement

a technology of brightness enhancement and paper, which is applied in the field of brightness enhancement, can solve the problems of decomposition of bleaching chemicals, and achieve the effect of enhancing paper brightness and paper brightness

Inactive Publication Date: 2007-06-14
NALCO CO
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  • Summary
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  • Application Information

AI Technical Summary

Benefits of technology

[0005] The present invention provides for a method of enhancing brightness of paper made from mechanical pulps that comprises the step of: adding an effective amount of one or more chelants and one or more surfactants to a bleaching stage in a papermaking process that involves the addition of hydrosulfite.
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Problems solved by technology

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Method used

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Examples

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examples

[0020] The efficacy of the combination of chelants and surfactants were studied in a hydrosulfite bleaching experiment conducted according to the following protocol.

[0021] The experiments must be conducted in an oxygen-free atmosphere to achieve reproducible results. Oxygen from air quickly oxidizes sodium hydrosulfite in the solution to sulfate and sulfite.

[0022] The following procedure was followed for all examples: (1) weigh out a pulp sample (5 g dry pulp per sample, calculate actual weight based on the consistency) in a 250-ml glass bottle; (2) add water and additives when needed, mix well; (3) close the bottle and degas them the sample with a flow of nitrogen for 10 min; (4) degas deionized (“DI”) water for 10 min; (5) place desired amount of hydrosulfite in a 100-ml flask, close it, fill with nitrogen, then add required amount of degassed DI water through a syringe and mix. Recommended concentration of hydrosulfite provides for about 1% in the bleached sample after adding 5...

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Abstract

A method of enhancing brightness of paper made from mechanical pulps or recycled pulps that comprise: adding an effective amount of one or more chelants and one or more surfactants to a bleaching stage of a papermaking process that involves the addition of hydrosulfite is disclosed.

Description

FIELD OF THE INVENTION [0001] This disclosure pertains to a method of enhancing brightness of paper produced from mechanical or recycled pulps. BACKGROUND OF THE INVENTION [0002] Bleaching of mechanical and recycled pulps during a papermaking process enhances the brightness of paper produced from these pulps. Mechanical pulps include groundwood (GW), refiner mechanical pulp (RMP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), chemimechanical pulp (CMP), variations thereof (e.g., stone GW, pressurized GW, thermo-RMP, pressure RMP, pressure TMP, chemi-RMP, long fiber CMP, thermomechanical chemi pulp); recycled pulp; and compositions containing mechanical, chemical and recycled pulps. Recycled pulps include any pulp obtained from recycled paper, for example newspapers. [0003] Some common bleaching chemicals utilized during a bleaching stage of a papermaking process include: sodium hydrosulfite; ammonium hydrosulfite; magnesium hydrosulfite; calcium hydrosulfite; zinc ...

Claims

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Application Information

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IPC IPC(8): D21C9/10
CPCD21C5/02D21C9/1042D21C9/1084Y02W30/64
Inventor DUGGIRALA, PRASAD Y.SHEVCHENKO, SERGEY M.
Owner NALCO CO
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