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US 6,187,135 B1Granted
Process for making recycled paper having improving strength properties
OwnerSun Ho Chunginventor
Life of this patent
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Abstract
A process for the manufacture of recycled paper having improved strength properties is achieved by replacing refiners by agitators, modifying extractor, applying effective amount of dispersion aids, and applying appropriate amount of dry strength additives.
Claims11
In an improved process for making recycled paper wherein fibers in waste paper stocks are dispersed, extracted from cleaned and screened furnish, refined to achieve required level of freeness of a furnish, and deposited on a wire and dewatered,
- the improvement comprising a process for improving strength properties of recycled paper comprising the steps of:
- replacing disk refiners, beaters and kneaders by agitators;
- removing fibril fragments from cleaned and screened furnish by a fiber extractor that extracts fibril fragments and does not extract short and long fibers;
- applying an effective amount of dispersion aids to a pulper;
- maintaining a pH of furnish at a head box of paper machine at least 5.5 and at highest 6.5;
- applying an appropriate amount of dry strength additives to furnish.
3 more elements
Dependencies are inferred from the claim text.