Calcium sulphate-based products

Patent metadata

Field	Value
Publication number	US-10131577-B2
Application number	US-201314654300-A
Country	US
Kind code	B2
Filing date	Dec 19, 2013
Priority date	Dec 21, 2012
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

This invention relates to improved high temperature resistant calcium sulphate-based products e.g. gypsum wallboard products and, in particular, to products having reduced shrinkage at high temperatures. The invention provides calcium sulphate-based product comprising gypsum and a shrinkage resistance additive. The shrinkage resistance additive is melamine polyphosphate or melamine pyrophosphate.

First claim

The invention claimed is:

1. A calcium sulphate-based product formed by drying an aqueous slurry comprising:
gypsum that is calcined and a shrinkage resistance additive, wherein:
the shrinkage resistance additive is melamine polyphosphate or melamine pyrophosphate, and
the calcium sulphate-based product has an area shrinkage of between 8-14% after heating to a temperature of 1000° C. over 120 minutes.

2. The product according to claim 1 , wherein the shrinkage resistance additive is provided in an amount from 0.1 to 20 wt %.

3. The product according to claim 2 , wherein the shrinkage resistance additive is provided in an amount from 2 to 5 wt %.

4. The product according to claim 1 , wherein the product is a wallboard, panel, tile, joint filler material or mould for metal casting.

5. The product according to claim 4 , wherein the product is a composite wallboard comprising a core of the gypsum and shrinkage resistance additive sandwiched between two liners.

6. The product according to claim 1 , wherein the shrinkage resistance additive is melamine polyphosphate.

7. A method for manufacturing the calcium sulphate-based product according to claim 1 , the method comprising:
mixing the gypsum that is calcined and the shrinkage resistance additive with water to provide an aqueous slurry; and
drying the aqueous slurry.

8. The calcium sulphate-based product comprising:
gypsum and a shrinkage resistance additive, wherein:
the shrinkage resistance additive is melamine polyphosphate or melamine pyrophosphate, and
the calcium sulphate-based product has a linear shrinkage between 5% and 10% at a temperature of 1000° C.

9. The product according to claim 8 , wherein the shrinkage resistance additive is provided in an amount from 0.1 to 20 wt %.

10. The product according to claim 9 , wherein the shrinkage resistance additive is provided in an amount from 2 to 5 wt %.

11. The product according to claim 8 , wherein the product is a wallboard, panel, tile, joint filler material or mould for metal casting.

12. The product according to claim 11 , wherein the product is a composite wallboard comprising a core of the gypsum and shrinkage resistance additive sandwiched between two liners.

13. The product according to claim 8 , wherein the shrinkage resistance additive is melamine polyphosphate.

14. A method for manufacturing the calcium sulphate-based product according to claim 8 , the method comprising:
mixing the gypsum that is calcined and the shrinkage resistance additive with water to provide an aqueous slurry; and
drying the aqueous slurry.

Assignees

• Certainteed Gypsum Inc

Inventors

• Fisher Robin

Classifications

• C04B2111/28

  Fire resistance, i.e. materials resistant to accidental fires or high temperatures · CPC title

• C04B24/003

  Phosphorus-containing compounds · CPC title

• B32B13/00

  Layered products comprising a {a layer of} water-setting substance, e.g. concrete, plaster, asbestos cement, or like builders' material · CPC title

• B32B2607/00

  Walls, panels · CPC title

• C04B28/14 Primary

  containing calcium sulfate cements {(gypsum-paper plates E04C)} · CPC title