Fire resistant gypsum board

• US 4,722,866 A
• Filed: 05/04/1987
• Issued: 02/02/1988
• Est. Priority Date: 04/09/1985
• Status: Expired due to Fees

• Current Assignee: G-P Gypsum Corporation (Golden Eagle Industries, Inc.)
• Original Assignee: Georgia-Pacific Corporation
• Inventors: Wilson, Glenn E., Lehnert, Charles W.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Monroe, James B.
• Application Number:
  US07/046,437
• Time in Patent Office: 274 Days
• Field of Search: 428/703, 428/70, 428/454, 428/411.1, 428/920, 428/426, 428/921, 428/428, 428/438, 106/15.05, 106/18.11
• US Class Current: 428/411.1
• CPC Class Codes: C04B 14/106 Kaolin
• CPC Class Codes: C04B 14/202 Vermiculite
• CPC Class Codes: C04B 14/383 Whiskers
• CPC Class Codes: C04B 14/42 Glass
• CPC Class Codes: C04B 2111/0062 Gypsum-paper board like materials
• CPC Class Codes: C04B 2111/00629 the covering sheets being made of material other than paper
• CPC Class Codes: C04B 28/14 containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: Y10S 428/92 Fire or heat protection feature
• CPC Class Codes: Y10S 428/921 Fire or flameproofing
• CPC Class Codes: Y10T 428/232 Encased layer derived from inorganic settable ingredient
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31634 Next to cellulosic

Abstract

A composition useful as the core of fire resistant gypsum board and comprising a major amount of set calcined gypsum and minor amounts of whisker fibers, glass fibers and clay.

Claims

1. Fire resistant gypsum wallboard having a core sandwiched between facing sheets and comprising the set product of at least about 80 wt. % of calcined gypsum, at least about 0.04 wt. % glass fibers, at least about 0.1 wt. % whisker fibers and at least about 1.5 wt. % clay.

2. Wallboard according to claim 1 having a core comprising the set product of:

space="preserve" listing-type="tabular">______________________________________ Wt. % ______________________________________ calcined gypsum about 80 to about 90;

glass fibers about 0.04 to about 1.0;

whisker fibers about 0.1 to about 2.0; and

clay about 1.5 to about 5.0. ______________________________________

3. Wallboard according to claim 2 having a core comprising the set product of:

space="preserve" listing-type="tabular">______________________________________ Wt. % ______________________________________ calcined gypsum about 83 to about 88;

glass fibers about 0.1 to about 0.4;

whisker fibers about 0.4 to about 1.0; and

clay about 1.5 to about 3.5. ______________________________________

4. Wallboard according to claim 2 wherein the core has a density of about 44 to about 50 lbs/cu. ft. and wherein the amounts and proportions of ingredients comprising the core are such that a core having a thickness of about 0.5 inch has a shrink resistance of no less than 75% and cracks no more than 6 inches/24 sq. in. after heating to about 1800°

F. for about 2 hours.

5. Wallboard according to any of claims 2, 3, or 4, wherein said whisker fibers are water-insoluble calcium sulfate anhydrite.

6. Wallboard according to claim 2 having a core wherein said whisker fibers have a testing consistency of about 100 to about 600 grams of water per 100 grams of whisker fibers and a length to diameter ratio of about 400:

1 to about 5;

1.

7. Wallboard according to claim 6 having a core wherein said whisker fibers have an average length to diameter ratio of about 20:

1 to about 30;

1.

8. Wallboard according to claim 2 having a core wherein said whisker fibers have a length of about 10 to about 400 micrometers.

9. Wallboard according to claim 8 having a core wherein said whisker fibers have an average length of about 35 to about 45 micrometers.

10. Wallboard according to claim 2 having a core wherein said whisker fibers have a testing consistency of about 200 to about 350 grams of water to 100 grams of fibers and a length to diameter ratio of about 200:

1 to about 10;

1.

11. Wallboard according to claim 10 having a core wherein said whisker fibers have a length of about 20 to 200 micrometers.

12. Wallboard according to claim 2 having a core which is substantially free from heat-expandable minerals.

13. Wallboard according to claim 2 having a core including at least about 0.5 wt. % vermiculite.

14. Wallboard according to claim 3 having a core including about 0.5 to about 1.5 wt % vermiculite.

15. Wallboard according to claim 4 having a core including about 0.8 to about 1.2 wt. % vermiculite.

16. Wallboard according to claim 2 wherein the clay is kaolin clay.

17. Wallboard according to claim 4 wherein the core comprises the set product of:

space="preserve" listing-type="tabular">______________________________________ Wt. % ______________________________________ calcined gypsum about 83 to about 88;

glass fibers about 0.1 to about 0.4;

whisker fibers about 0.4 to about 1.0; and

clay about 1.5 to about 3.5. ______________________________________

18. Wallboard according to claim 4 or 17 wherein said whisker fibers are water insoluble calcium sulfate anhydrite having a testing consistency of about 100 to about 800 grams of water per 100 grams of whisker fibers and a length to diameter ratio of about 400:

1 to about 5;

1.

19. Wallboard according to claim 2 wherein the core is sandwiched between fiberglass facing sheets.

20. Wallboard according to claim 2 wherein the core is sandwiched between plastic scrim facing sheets.

21. Wallboard according to claim 2 wherein the core is sandwiched between paper facing sheets.