Method of preparing a gypsum-based product

Patent metadata

Field	Value
Publication number	US-12098097-B2
Application number	US-201917293337-A
Country	US
Kind code	B2
Filing date	Nov 7, 2019
Priority date	Nov 15, 2018
Publication date	Sep 24, 2024
Grant date	Sep 24, 2024

Abstract

A method of preparing a gypsum-based product comprises the steps of mixing calcined gypsum with polymer particles and water to provide a slurry. The polymer particles comprise principally polyvinyl acetate, and have a particle size distribution, measured using laser diffractometry, such that particles having a diameter of 4.5 μm or less provide at least 90% of the total particle volume.

First claim

The invention claimed is:

1. A method of preparing a gypsum-based product, comprising the steps of mixing calcined gypsum with polymer particles and water to provide a slurry, the polymer particles comprising principally polyvinyl acetate, wherein
the polymer particles have a particle size distribution, measured using laser diffractometry, such that particles having a diameter of 4.5 μm or less provide at least 90% of the total particle volume,
wherein the polymer particles are present in the slurry in an amount of 15 wt % or less relative to the calcined gypsum, and
wherein the particles additionally comprise polyvinyl alcohol and the polyvinyl alcohol phase is present as a surface layer extending partially or wholly around the exterior of the particle.

2. The method of claim 1 , wherein the polymer particles have a particle size distribution, measured using laser diffractometry, such that particles having a diameter of 4 μm or less provide at least 90% of the total particle volume.

3. The method of claim 2 , wherein the polymer particles have a particle size distribution, measured using laser diffractometry, such that particles having a diameter of 3.5 μm or less provide at least 90% of the total particle volume.

4. The method of claim 1 , wherein the average polyvinyl acetate content of the particles is at least 90% by volume.

5. The method of claim 1 , wherein the polymer particles are provided in the form of a water-based emulsion.

6. The method of claim 5 , further comprising the step of incorporating a further quantity of water into the slurry, in addition to the water-based emulsion.

7. The method of claim 1 , wherein the polymer particles are present in the slurry in an amount of at least 1 wt % relative to the calcined gypsum.

8. The method of claim 1 , further comprising the step of incorporating fibres into the slurry.

9. The method of claim 8 , wherein the fibres are present in the slurry in an amount of at least 1 wt % relative to the calcined gypsum.

10. The method of claim 1 , wherein the gypsum-based product is a board.

11. The method according to claim 10 , wherein the board is provided with a liner on at least one face, wherein the liner is a paper liner or a glass fibre mat.

12. The method of claim 1 , further comprising the steps of shaping the slurry and allowing to set to provide a gypsum plasterboard.

Assignees

• Saint Gobain Placo

Inventors

• Walton Kirsty
• Jones Nicholas
• Cutler David
• Jupp Nicola
• Brooks Laura

Classifications

• C04B2111/00629

  the covering sheets being made of material other than paper · CPC title

• C04B28/14 Primary

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

• C04B20/1033 Primary

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C04B14/42

  Glass · CPC title

• B28C5/406

  and mixing with binding material · CPC title