Gypsum composition for dry-curing coating material, gypsum-based coating material, and construction method for gypsum-based coating material

Patent metadata

Field	Value
Publication number	US-10654754-B2
Application number	US-201615772369-A
Country	US
Kind code	B2
Filing date	Dec 7, 2016
Priority date	Dec 11, 2015
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

There is provided a gypsum composition for a drying type coating material, the gypsum composition, when made into a gypsum-based coating material by addition of water, capable of forming a coating film in which color unevenness is suppressed even though the coating film is thin and smooth. This gypsum composition for a drying type coating material contains hemihydrate gypsum having a mean particle diameter of 50 μm or less, calcium carbonate having a mean particle diameter of 50 μm or less, and a setting retarder, wherein the gypsum composition has a content of calcium carbonate of 100 to 400 parts by mass and a content of the setting retarder of 0.1 parts by mass or more each based on 100 parts by mass of the hemihydrate gypsum.

First claim

The invention claimed is:

1. A gypsum composition for a coating material for forming a coating film through drying the coating material, the gypsum composition comprising:
hemihydrate gypsum having a mean particle diameter in a range of 50 μm or less;
calcium carbonate having a mean particle diameter in a range of 50 μm or less; and
a setting retarder,
wherein
the gypsum composition has a content of the calcium carbonate in a range from 10 to 400 parts by mass and a content of the setting retarder in a range of 0.1 parts by mass or more each relative to 100 parts by mass of the hemihydrate gypsum,
the hemihydrate gypsum comprises at least one material selected from the group consisting of α-hemihydrate gypsum, β-hemihydrate gypsum, and III-anhydrous gypsum, and
initial setting time of a hydration reaction that occurs when water is added to the gypsum composition so as to form a coating material is in a range of 24 hours or longer,
wherein the initial setting time of the hydration reaction is measured according to JIS A 6904, except that normal consistency in the JIS A 6904 is set at a penetration depth of 20±2 mm, and
the initial setting time of the hydration reaction corresponds to an initial setting in the JIS A 6904.

2. The gypsum composition for a coating material according to claim 1 ,
wherein the hemihydrate gypsum has the mean particle diameter in a range of 40 μm or less, and
the calcium carbonate has the mean particle diameter in a range of 40 μm or less.

3. The gypsum composition for a coating material according to claim 1 ,
wherein the gypsum composition has the content of the calcium carbonate in a range from 10 to 200 parts by mass relative to 100 parts by mass of the hemihydrate gypsum.

4. The gypsum composition for a coating material according to claim 1 ,
wherein the gypsum composition has the content of the setting retarder in a range from 0.1 to 10 parts by mass relative to 100 parts by mass of the hemihydrate gypsum.

5. The gypsum composition for a coating material according to claim 1 ,
wherein the gypsum composition has the content of the setting retarder in a range from 0.1 to 2 parts by mass relative to 100 parts by mass of the hemihydrate gypsum.

6. The gypsum composition for a coating material according to claim 1 ,
wherein the setting retarder is at least one material selected from the group consisting of citric acid, succinic acid, acetic acid, malic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and salts thereof, and sucrose, starch, and decomposition products of protein.

7. The gypsum composition for a coating material according to claim 1 ,
wherein powder X-ray diffraction of the coating film, which is obtained by adding water to the gypsum composition for a coating material and then dry-setting a resultant mixture, shows a diffraction peak originating from the hemihydrate gypsum but does not show a diffraction peak originating from dihydrate gypsum formed by a hydration reaction of the hemihydrate gypsum.

8. The gypsum composition for a coating material according to claim 1 ,
wherein the initial setting time is in a range of 48 hours or longer.

9. The gypsum composition for a coating material according to claim 1 ,
wherein the content of the calcium carbonate in the gypsum composition is in a range from 50 to 400 parts by mass relative to 100 parts by mass of the hemihydrate gypsum.

10. A gypsum-based coating material comprising:
hemihydrate gypsum having a mean particle diameter in a range of 50 μm or less;
calcium carbonate having a mean particle diameter in a range of 50 μm or less;
a setting retarder; and
water,
wherein the gypsum-based coating material forms a coating film through drying the coating material,
the gypsum-based coating material has a content of the calcium carbonate in a range from 10 to 400 parts by mass and a content of the setting retarder in a range of 0.1 parts by mass or more each relative to 100 parts by mass of the hemihydrate gypsum,
the hemihydrate gypsum comprises at least one material selected from the group consisting of α-hemihydrate gypsum, β-hemihydrate gypsum, and III-anhydrous gypsum, and
initial setting time of a hydration reaction that occurs when water is added to a combination of the hemihydrate gypsum, the calcium carbonate, and the setting retarder so as to form the gypsum-based coating material is in a range of 24 hours or longer,
wherein the initial setting time of the hydration reaction is measured according to JIS A 6904, except that normal consistency in the JIS A 6904 is set at a penetration depth of 20±2 mm, and
the initial setting time of the hydration reaction corresponds to an initial setting in the JIS A 6904.

11. The gypsum-based coating material according to claim 10 , comprising the water in a range from 30 to 60 parts by mass relative to 100 parts by mass of a total amount of the combination of the hemihydrate gypsum, the calcium carbonate, and the setting retarder.

12. The gypsum-based coating material according to claim 10 , having a pH in a range of 7 or more and less than 9.

13. The gypsum-based coating material according to claim 10 ,
wherein powder X-ray diffraction of the coating film, which is obtained by dry-setting the gypsum-based coating material, shows a diffraction peak originating from the hemihydrate gypsum but does not show a diffraction peak originating from dihydrate gypsum formed by a hydration reaction of the hemihydrate gypsum.

14. The gypsum-based coating material according to claim 10 ,
wherein the initial setting time is in a range of 48 hours or longer.

15. The gypsum-based coating material according to claim 10 ,
wherein the content of the calcium carbonate in the combination of the hemihydrate gypsum, the calcium carbonate, and the setting retarder is in a range from 50 to 400 parts by mass relative to 100 parts by mass of the hemihydrate gypsum.

16. A construction method for forming a coating film with a gypsum-based coating material, the method comprising:
applying the gypsum-based coating material according to claim 10 on an adherend as a substrate for the gypsum-based coating material; and
drying the coated gypsum-based coating material so as to form the coating film on the adherend.

17. The construction method according to claim 16 ,
wherein an amount of the gypsum-based coating material applied on the adherend is in a range from 1.0 to 6.3 kg/m 2 .

18. The construction method according to claim 16 ,
wherein a coating thickness of the gypsum-based coating material applied on the adherend is in a range from 0.5 to 3 mm.

19. The construction method according to claim 16 , the method further comprising forming a water-repellent coating film on the coating film formed of the gypsum-based coating material.

20. The construction method according to claim 16 ,
wherein the adherend is at least one material selected from the group consisting of cement bases, gypsum bases, woody bases, lime plaster walls, plastic bases, and metal bases.

Assignees

• Yoshino Gypsum Co
• Yushino Gypsum Co Ltd

Inventors

• Yokoyama Itaru
• Tanaka Yoshikazu

Classifications

• C04B2111/00689

  of the setting type · CPC title

• C04B2111/00517

  for masonry · CPC title

• C04B2111/00482

  Coating or impregnation materials · CPC title

• E04F13/02

  of plastic materials hardening after applying, e.g. plaster (surface treatment in painting technique B44D; inorganic or bituminous masses C04B; organic plastics C08L {; implements for applying plasticised materials E04F21/02}) · CPC title

• C04B28/14 Primary

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