US 2007/0163735 A1 · Method for reducing brightness reversion of mechanical pulps and high-yield chemical pulps

Abstract

The present invention concerns a process for reducing the susceptibility of lignocellulosic material to unwanted yellowing, particularly yellowing caused by light and heat. According to the invention, the fibres are activated enzymatically or chemically and then contacted with a modifying agent capable of bonding to the oxidized fibre material, rendering the lignocellulosic fibre material improved resistance to brightness reversion. By means of the invention, brightness reversion caused by light or heat or a combination thereof can be retarded and even stopped.

Claims19

Dependent claims

A process for producing a fibre material having reduced susceptibility to yellowing,

comprising activating the fibres of the matrix with an oxidizing agent capable of oxidizing phenolic or similar structural groups, which may undergo reactions conducive to the formation of coloured sites on the fibres, and attaching to the oxidized sites at least one modifying agent to block the reactivity of the oxidized sites.

Dependencies are inferred from the claim text.

Facts

Application

10/583,340Filed 23 Dec 2004

Priority

FI 2003190423 Dec 2003

Published

19 Jul 2007

Term ends

Not estimatedThe source records don’t support an estimate.

Classification6 codes

D21C 9/005
By chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives: organic compounds
D21H 21/143
Characterised by function or properties in or on the paper: agents preventing ageing of paper, e.g. radiation absorbing substances
D21C 5/005
Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting…:…
D21H 11/20
Modified by a particular after-treatment: chemically or biochemically modified fibres

Method for reducing brightness reversion of mechanical pulps and high-yield chemical pulps

Life of this patent

Method for reducing brightness reversion of mechanical pulps and high-yield chemical pulps

Life of this patent

Abstract

Claims19