Stucco properties through aging at elevated temperatures and high humidity level

Patent metadata

Field	Value
Publication number	US-12227450-B2
Application number	US-201716636604-A
Country	US
Kind code	B2
Filing date	Aug 4, 2017
Priority date	Aug 4, 2017
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

The invention pertains to a method for stabilizing stucco wherein
a fresh stucco is provided; water is added to the fresh stucco to obtain moistened stucco, and the moistened stucco is maintained at a temperature of at least 30° C. for a time interval of at least 30 minutes to obtain a stabilized stucco.

The process allows inter alia for an easy adjustment of the activity of the stabilized stucco, which is useful to e.g. adjust setting time of a corresponding stucco slurry. The invention further pertains to a method for producing gypsum plasterboards, wherein a stabilized stucco obtained with the above method is used.

First claim

The invention claimed is:

1. Method for stabilizing stucco wherein
a fresh stucco is provided at a temperature of at least 50° C.;
water is added to the fresh stucco to obtain moistened stucco, and
maintaining the moistened stucco at a temperature of at least 75° C. and less than 90° C. for a time interval of at least 30 min and less than 24 hours to obtain a stabilized stucco, wherein water is added to the fresh stucco in an amount such that the stabilized stucco contains free moisture in an amount of less than 3 wt. %, based on the weight of the stabilized stucco, and wherein no heating of the moistened stucco using an external device occurs.

2. Method according to claim 1 , wherein the water is provided in vapor form.

3. Method according to claim 1 , wherein the moistened stucco is maintained under an atmosphere of at least 50% rel. humidity.

4. Method according to claim 1 , wherein a particle size D98 of the stabilized stucco is adjusted to less than 1 mm.

5. Method according to claim 1 , wherein the stabilized stucco is ground.

6. Method according to claim 1 , wherein the stabilized stucco is mixed with fresh stucco.

7. Method according to claim 1 , wherein water is added to the fresh stucco in an amount such that the stabilized stucco contains free moisture in an amount of 0.5 to 1.5 wt. % based on the weight of the stabilized stucco.

Assignees

• Knauf Gips Kg

Inventors

• Dietz Stephan
• Hartmann Alexander
• Fraser Thomas
• Baier Manfred
• Förthner Sebastian
• Karakoussis Stergios
• Paraskov Georgi
• Schneiderbanger Reiner

Classifications

• C04B2111/60

  Flooring materials · CPC title

• C04B2111/00672

  Pointing or jointing materials · CPC title

• C04B2111/0062

  Gypsum-paper board like materials · CPC title

• C04B2103/50

  Defoamers, air detrainers · CPC title

• C04B28/145

  Calcium sulfate hemi-hydrate with a specific crystal form · CPC title