Polymer-modified fiber-cement composition

• US 20040229978A1
• Filed: 05/15/2003
• Published: 11/18/2004
• Est. Priority Date: 05/15/2003
• Status: Active Grant

• Current Assignee: Rohm and Haas Company (Dow, Inc.)
• Original Assignee: Rohm and Haas Company (Dow, Inc.)
• Inventors: Bowe, Michael Damian
• Granted Patent: US 7,148,270 B2
• Time in Patent Office: Days
• US Class Current: 524/2
• CPC Class Codes: C04B 14/04 Silica-rich materials; Silicates
• CPC Class Codes: C04B 18/24 Vegetable refuse, e.g. rice husks, maize-ear refuse; Cellulosic materials, e.g. paper , cork
• CPC Class Codes: C04B 2103/0065 Polymers characterised by their glass transition temperature (Tg)
• CPC Class Codes: C04B 24/26 obtained by reactions only involving carbon-to-carbon unsaturated bonds C04B24/243 takes precedence
• CPC Class Codes: C04B 24/2641 Polyacrylates; Polymethacrylates
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 40/0082 making use of a rise in temperature, e.g. caused by an exothermic reaction
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

A method for providing a polymer-modified fiber-cement composite by forming an aqueous composition including admixing an emulsion polymer having a glass transition temperature (Tg) of from −25° C. to 150° C., cement, cellulosic fibers, siliceous material, and water; forming a composite precursor by removal of at least some of the water; and curing/drying the composite precursor at a temperature at least 10° C. higher than the Tg of the polymer is provided. In an alternative embodiment the emulsion polymer is applied to the composite precursor. Polymer-modified fiber-cement composites formed by the method of the invention are also provided.

Claims

1. A method for providing a polymer-modified fiber-cement composite comprising

forming an aqueous composition comprising admixing an emulsion polymer having a glass transition temperature (Tg) of from −

25°

C. to 150°

C. cement, cellulosic fibers, siliceous material, and water;

forming a composite precursor by removal of at least some of said water; and

curing/drying said composite precursor at a temperature at least 10°

C. higher than the Tg of said polymer.

2. The method of claim 1 wherein said composite comprises from 0.1% to 15% polymer by weight on a dry polymer and dry composite basis.

3. The method of claim 2 wherein said polymer has a glass transition temperature of from 50°

C. to 150°

C.

4. The method of claim 1 wherein said emulsion polymer is cement-unstable.

9. A polymer-modified fiber-cement composite formed by the method of claim 1 or claim 5.

5. A method for providing a polymer-modified fiber-cement composite comprising

forming an aqueous composition comprising admixing cement, cellulosic fibers, siliceous material, and water;

forming a composite precursor by removal of at least some of said water;

contacting said composite precursor with an emulsion polymer having a glass transition temperature (Tg) of from −

25°

C. to 150°

C.; and

curing/drying said composite precursor at a temperature at least 10°

C. higher than the Tg of said polymer.

6. The method of claim 5 wherein said composite comprises from 0.1% to 15% polymer by weight on a dry polymer and dry composite basis.

7. The method of claim 6 wherein said polymer has a glass transition temperature of from 50°

C. to 150°

C .

8. The method of claim 5 wherein said emulsion polymer is cement-unstable.