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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.:

US 4801355 B1

PDFFull Text
Date of Patent:
Jan. 31, 1989

Filed:

Jan. 16, 1987

Tabular acicular gypsum and method of filling paper

Applicant:
Inventors:

Norman E Johnstone, Schaumburg, IL (US);

John C Gaynor, Des Plaines, IL (US);

Robert W Erickson, Lindenhurst, IL (US);

Assignee:

United States Gypsum Company, Chicago, IL (US);

Attorneys:

Lorenzen; John M.

Robinson; Robert H.

Primary Examiner:

Peter Chin

Int. Cl.
CPC ...
D21H / ;
U.S. Cl.
CPC ...
1621813 ;
Abstract

A tabular variety of acicular gypsum crystal filler is prepared by hydrating calcium sulfate dihydrate particles in a seeded continuously stirred reactor at a low level of super-saturation to obtain crystals having an aspect ratio of about 100:10:1 and average length in the longest dimension of about 100-450 micrometers. For the manufacture of paper, the obtained tabular crystal slurry may be directly added to the paper pulp before web formation to obtain a filled paper having high filler retention.

Find Patent Forward Citations

Johnstone, Norman. (1989). Tabular acicular gypsum and method of filling paper (U.S. Patent No. 4801355). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/4801355

Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile

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