Patent · US Expired

Process and composition for bleaching wood pulp

US4752354A · kind A · utility

7Cited by

1References

9Claims

0Family size

Assignee

Benckiser-Knapsack GmbH · DE

Inventors

Harald Beurich · Ladenburg, DE
Margarete Scholl · Mannheim, DE

Key dates

Filing date	Jul 21, 1986
Grant date	Jun 21, 1988
Priority date	—
Expiry date	Jul 21, 2006

Classification

Technology area (CPC D)Textiles; Paper
CPC primaryD21C9/1005
WIPO fieldTextile and paper machines
WIPO sectorMechanical engineering

Abstract

A process for the oxidative or reductive bleaching of wood pulp, especially in the presence of heavy metal salts, in which a complex former combination containing at least one phosphonic acid, at least one polyhydroxycarboxylic acid and at least one phosphate or salts thereof is added to a wood pulp slurry in an amount of from 0.5 to 50%, based on the dry mass of the wood pulp, and subsequent bleaching is carried out in the presence of a reducing agent. Also provided is a complex former combination for use in the oxidative or reductive bleaching of wood pulp, comprising at least one phosphonic acid, at least one polyhydroxycarboxylic acid and at least one phosphate or salts thereof.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.