Water resistant cementitious article and method for preparing same

• US 8,568,544 B2
• Filed: 10/28/2011
• Issued: 10/29/2013
• Est. Priority Date: 02/12/2007
• Status: Active Grant

• Current Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Original Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Inventors: Engbrecht, Dick C., Liu, Qingxia, Shake, Michael P., Wang, Xuming, Miller, David Paul, Bolind, Michael L., Reed, Paul, Roelfs, Donald L., Bury, Rafael
• Primary Examiner(s): ORLANDO, MICHAEL N
• Application Number:
  US13/283,672
• Publication Number:
  US 20120040168A1
• Time in Patent Office: 732 Days
• Field of Search: 156/39, 156/41, 156/45
• US Class Current: 156/39
• CPC Class Codes: B32B 13/14 next to a fibrous or filamentary layer
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 2103/105 for reactions involving organo-silicon compounds
• CPC Class Codes: C04B 2111/00612 as one or more layers of a layered structure
• CPC Class Codes: C04B 2111/00629 the covering sheets being made of material other than paper
• CPC Class Codes: C04B 2111/27 Water resistance, i.e. waterproof or water-repellent materials
• CPC Class Codes: C04B 22/066 Magnesia; Magnesium hydroxide
• CPC Class Codes: C04B 22/16 containing phosphorus in the anion, e.g. phosphates
• CPC Class Codes: C04B 24/08 Fats; Fatty oils; Ester type waxes; Higher fatty acids, i.e. having at least seven carbon atoms in an unbroken chain bound to a carboxyl group; Oxidised oils or fats
• CPC Class Codes: C04B 24/42 Organo-silicon compounds
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 28/14 containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: C04B 38/10 by using foaming agents C04B38/02 takes precedenceor by using mechanical means, e.g. adding preformed foam
• CPC Class Codes: C04B 7/02 Portland cement
• CPC Class Codes: E04C 2/043 of plaster E04C2/049 takes precedence
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 442/2164 Coating or impregnation specified as water repellent

Abstract

A fibrous mat-faced cementitious article comprising (a) a cementitious core, and (b) a first fibrous mat comprising polymer or mineral fibers and a hydrophobic finish on at least one surface thereof, wherein the hydrophobic finish is in contact with the cementitious core, and a method of preparing a fibrous mat-faced cementitious article, as well as a method of preparing a water-resistant cementitious article comprising (a) preparing an aqueous siloxane dispersion, wherein the dispersion comprises about 4 wt. % to about 8 wt. % siloxane, (b) combining the siloxane dispersion with a cementitious mixture to provide a cementitious slurry, (c) depositing the cementitious slurry onto a substrate, and (d) allowing the cementitious slurry to harden, thereby providing a cementitious article.

Claims

1. A fibrous mat-faced cementitious article comprising:

(a) a cementitious core,

(b) a first fibrous mat comprising polymer or mineral fibers, the mat having at least a first surface facing the cementitious core,

(c) a hydrophobic film having a thickness of at least about 25 μ

m disposed on at least the first surface the mat, the film comprising talc, wax, a hydrophobic resin, a silicone-based compound, a fatty acid or salt thereof, polyethylene glycol, a hydrocarbon or fluorocarbon surfactant having 12 or more carbon atoms, or a combination thereof, wherein;

(i) the hydrophobic film is in contact with the cementitious core, and

(ii) the first fibrous mat bearing the hydrophobic film adheres to the cementitious core such that no greater than about 50% of the thickness of the first fibrous mat is embedded in the cementitious core.

2. The cementitious article of claim 1, wherein polymer or mineral fibers are glass fibers, polyester fibers, or a combination thereof.

3. The cementitious article of claim 1 further comprising a second fibrous mat comprising polymer or mineral fibers, wherein the cementitious core is disposed between the first fibrous mat and the second fibrous mat.

4. The cementitious article of claim 1, wherein the cementitious core is substantially free of mineral or paper fibers.

5. The cementitious article of claim 1, wherein the cementitious core comprises a hydrophobic additive.

6. The cementitious article of claim 5, wherein the hydrophobic additive is a silicone-based material.

7. The cementitious article of claim 1, wherein the cementitious core comprises unstable and stable soaps.

8. The cementitious article of claim 1, wherein the cementitious core comprises a polyphosphate.

9. The cementitious article of claim 8, wherein the polyphosphate is sodium trimetaphosphate.

23. The cementitious article of claim 1, wherein when water is applied to the hydrophobic film, a contact angle of greater than about 70°

is formed.

24. The cementitious article of claim 1, wherein when water is applied to the hydrophobic film, a contact angle of between about 90°

to about 120°

is formed.

10. A method of preparing a fibrous mat-faced cementitious article comprising:

(a) providing a first fibrous mat comprising polymer or mineral fibers, the mat having at least a first surface facing the cementitious core;

(b) depositing a hydrophobic film having a thickness of least about 25 μ

m on the first surface of the fibrous mat,

(c) depositing a cementitious slurry on the first surface of the fibrous mat with the hydrophobic film, and

(d) allowing the cementitious slurry to harden and adhere to the hydrophobic film and the fibrous mat, such that no greater than about 50% of the thickness of the fibrous mat is embedded in the cementitious core.

11. The method of claim 10, wherein the hydrophobic film comprises talc, wax, a hydrophobic resin, a silicone-based compound, a fatty acid or salt thereof, polyethylene glycol, a hydrocarbon or fluorocarbon surfactant having 12 or more carbon atoms, or a combination thereof.

12. The method of claim 10, wherein the method further comprises depositing a hydrophobic film on the fibrous mat before depositing the cementitious slurry on the first fibrous mat.

13. The method of claim 12, wherein the method further comprises drying the hydrophobic film before depositing the cementitious slurry on the first fibrous mat.

14. The method of claim 10, wherein the polymer or mineral fibers are glass fibers, polyester fibers, or a combination thereof.

15. The method of claim 10 further comprising contacting the cementitious slurry with a second fibrous mat prior to allowing the cementitious slurry to harden, wherein the cementitious slurry is disposed between the first fibrous mat and the second fibrous mat.

16. The method of claim 10, wherein the cementitious slurry is substantially free of paper or mineral fibers.

17. The method of claim 10, wherein the cementitious slurry comprises a hydrophobic additive.

18. The method of claim 17, wherein the hydrophobic additive is a siloxane.

19. The method of claim 10, wherein the cementitious slurry is mixed in a mixer comprising a discharge conduit, and foam is added to the cementitious slurry in the discharge conduit prior to depositing the slurry on the first fibrous mat.

20. The method of claim 10, wherein the cementitious slurry comprises pre-blended unstable and stable soaps.

21. The method of claim 10, wherein the cementitious slurry comprises a polyphosphate.

22. The method of claim 21, wherein the polyphosphate is sodium trimetaphosphate.

25. The method of claim 10, wherein when water is applied to the hydrophobic film, a contact angle of greater than about 70°

is formed.

26. The method of claim 10, wherein when water is applied to the hydrophobic film, a contact angle of between about 90°

to about 120°

is formed.