摘要 |
Methods to enhance the brightness and brightness stability of paper and paperboard made with Mechanical Pulp are described and claimed. The method involves applying a Penetrant Compound to paper or paperboard in an amount from about 0.001 percent to about 1 percent by weight. The Penetrant Compound can have one component that is either polyamino polyether methylene phosphonate (PAPEMP) and alpha-glucoheptonic-gamma-lactone (GL); or the Penetrant Compound can have two components, where the first component is selected from the group consisting of PAPEMP and GL and the second component is an inorganic salt; or the Penetrant Compound can have three components where one component is selected from the group consisting of PAPEMP and GL, the second component is selected from the group consisting of 3,5-dimethylperhydrothiadiazine-2-thion and dialkyldithiocarbamates and the third component is an inorganic salt.
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