The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 29, 1985
Filed:
Aug. 06, 1984
Ching-Hua Tay, Mississauga, CA;
Raymond S Fairchild, Burlington, CA;
Abitibi-Price Inc., Toronto, CA;
Abstract
Wood pulps, particularly sulphonate pulps, such as jack pine ultra-high-yield pulps produced by sulphonation, are readily discolored by metal ions commonly found in paper mills. Additions of 0.001 to 2% on pulp dry basis of tin ions, especially derived from stannous compounds, to wood pulps effectively brighten the pulps at ambient temperature. Metal ions such as ferrous, ferric, cupric, aluminum, nickel and manganese are common discoloring ions and pulps containing these ions can be brightened by the addition of tin ions particularly derived from stannous chloride, stannous sulphate, stannous tartrate, stannous oxolate, stannic chloride and stannic sulphate, the tin ions as Sn.sup.+2 being added in an amount to provide a ratio of stannous ions to discoloring metal ions up to about 2:1, preferably about 1.5:1.