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US 8,617,356 B2Granted
Compositions and processes for paper
AssigneeNalco Company
InventorsPrasad Duggirala, Sergey Shevchenko
Life of this patent
Estimating the term…
Abstract
Compositions and processes that enhance the brightness and improve color of pulp or paper when applied during different stages of the papermaking process involving optical brighteners are identified. Used in combination with optical brighteners and/or chelants the described agents produce a synergistic effect not previously identified in the paper process.
Claims10
A method of activating an optical brightening agent, the method comprising the steps of:
- contacting an optical brightening agent with a reducing agent before the optical brightening agent is added to pulp in the wet end of a papermaking process or tissue making process wherein the reducing agent is in an amount of 0.05 to 2% on oven-dried pulp.
Dependencies are inferred from the claim text.