Method for preventing the discoloration of paper and paper treated to prevent discoloring
AssigneeAsahi Denka Kogyo Kabushiki Kaisha
InventorsMitsuo Akutsu, Syuji Iwakura
Life of this patent
Estimating the term…
Abstract
A process for treating paper to prevent discoloration when exposed to light which comprises adding 1% to 10% by weight of hypophosphorous acid or its salt based on the paper at any stage during or after paper making and maintaining said hypophosphorous acid or its salt therein. The invention also provides paper which contains hypophosphorous acid or its salt to prevent discoloration when exposed to light.
Claims8
A process for treating paper which comprises adding to paper from 1 to 10% by weight of hypophosphorous acid or its salt based on the paper in terms of dry matter in the paper by spraying onto said paper said hypophosphorous acid or its salt after papermaking to provide a treated paper containing an effective amount of said hypophosphorous acid or its salt to prevent discoloration of the paper when exposed to light.
Dependencies are inferred from the claim text.