Neutral sized paper for use in the production of gypsum wallboard
US4853085A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 1982 |
| Grant date | Aug 1, 1989 |
| Priority date | — |
| Expiry date | Nov 15, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31996
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A paper particularly adapted for use as cover sheets in the production of gypsum wallboard, the paper having improved porosity and strength to permit better drainage and more rapid drying in the production of the paper to permit less fiber to be utilized, and to permit less heat to be utilized in drying the paper, providing for production of superior gypsum board. The paper comprises in weight percent: PA1 (A) fibers having a fiber freeness of from about 350 to 550 ml. Canadian Standard Freeness, PA1 (B) a buffering agent in an amount from about 0.25 to about 10%, PA1 (C) a neutral sizing agent in an effective amount to prevent water penetration, and PA1 (D) a cationic starch. In a preferred embodiment the paper is treated with a neutral internal sizing agent during its formation, and subsequently treated with a surface sizing agent after formation of the paper, in order to provide certain properties including better adhesion to the gypsum core.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.