Wastepaper deinking process
US4618400A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1986 |
| Grant date | Oct 21, 1986 |
| Priority date | — |
| Expiry date | Jan 10, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/64
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A method for the deinking of wastepaper which comprises converting the wastepaper to a pulp, contacting the pulp with an aqueous medium of alkaline pH containing between about 0.2 and 2 percent by weight, calculated on dry weight of the pulp, of a deinking agent which is one or a mixture of certain thiol ethoxylate compounds, and treating the resulting pulp-containing medium to remove suspended or dispersed ink. The use of a thiol ethoxylate deinking agent offers a high level of performance in such a deinking process, both from the standpoint of the overall brightness and dirt count of paper prepared from the deinked pulp. In certain specific embodiments, the invention further comprises a step for treating thiol ethoxylate containing process streams and effluents to convert the surface active deinking agent to low-foaming sulfonyl derivatives, or to degrade the deinking agent to non-surface-active matter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.