The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 13, 2010
Filed:
Jan. 09, 2004
Aarto Paren, Vaasa, FI;
Jukka Jäkärä, Siivikkala, FI;
Ilkka Renvall, Espoo, FI;
Jonni Ahlgren, Vaasa, FI;
Riitta Laitinen, Oulu, FI;
Jussi Nikkarinen, Vaasa, FI;
Tapio Viitanen, Rauma, FI;
Aarto Paren, Vaasa, FI;
Jukka Jäkärä, Siivikkala, FI;
Ilkka Renvall, Espoo, FI;
Jonni Ahlgren, Vaasa, FI;
Riitta Laitinen, Oulu, FI;
Jussi Nikkarinen, Vaasa, FI;
Tapio Viitanen, Rauma, FI;
Kemira Oyj, Helsinki, FI;
Abstract
The present invention relates to a process for bleaching a cellulosic fibre material with a peroxide compound in an aqueous alkaline medium, comprising a bleaching step wherein: a) a first polymer (A) comprising a homopolymer of acrylic acid, methacrylic acid or maleic acid, or a copolymer of acrylic acid and/or methacrylic acid with an unsaturated dicarboxylic acid, and a solution of a second polymer (B) comprising a poly-alpha-hydroxyacrylic acid or a salt thereof, are added to a cellulosic fibre material, and b) thereafter adding a peroxide compound and an alkaline substance and carrying out the bleaching.