Fiber reinforcement material, products made therefrom, and method for making the same

• US 6,753,081 B1
• Filed: 02/21/2001
• Issued: 06/22/2004
• Est. Priority Date: 02/21/2001
• Status: Expired due to Term

• Current Assignee: Forta, LLC
• Original Assignee: Forta Corporation
• Inventors: Pitts, H. Charles Jr., Biddle, Daniel T., Lovett, Jeffrey B.
• Primary Examiner(s): Kelly, Cynthia H.
• Assistant Examiner(s): Thompson, C
• Application Number:
  US09/790,353
• Time in Patent Office: 1,217 Days
• Field of Search: 428/374, 428/359, 428/370, 428/373, 428/362, 525/240
• US Class Current: 428/373
• CPC Class Codes: C04B 16/0625 Polyalkenes, e.g. polyethylene
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: Y10T 428/24993 Fiber is precoated
• CPC Class Codes: Y10T 428/2904 Staple length fiber
• CPC Class Codes: Y10T 428/2909 Nonlinear [e.g., crimped, coiled, etc.]
• CPC Class Codes: Y10T 428/2924 Composite
• CPC Class Codes: Y10T 428/2929 Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• CPC Class Codes: Y10T 428/2931 Fibers or filaments nonconcentric [e.g., side-by-side or eccentric, etc.]

Abstract

The present invention provides a synthetic fiber blend and methods for its use comprising a first fiber component formed of a homopolymer polypropylene fiber and a second fiber component being a copolymer formed of a polypropylene and a high density polyethylene. The first fiber component is fibrillated and the second fiber component is a twisted bundle comprised of multiple strands of a nonfibrillating monofilament. The synthetic fiber blend imparts improved reinforcement properties to the building materials to which they are added. In particular, the synthetic fiber blend when incorporated into a building material provides reduced permeability, increased fatigue strength, improved toughness, and reduced plastic shrinkage. The unique combination of the twisted second fiber component blended with the first fiber component provides improved mixability and uniform distribution of the synthetic fiber blend in cementitious materials.

Claims

1. A synthetic fiber blend for use as reinforcement for cementitious material, comprising:

a first fiber component formed of a homopolymer polypropylene fiber wherein the first fiber component is fibrillated; and

a second fiber component being discrete from the first fiber component and being a copolymer formed of a polypropylene and a high density polyethylene, the second fiber component being a plurality of monofilaments twisted to form a non-interconnected bundle.

2. The synthetic fiber blend of claim 1, wherein the first fiber component is present in the synthetic fiber blend in amounts ranging from about 5 to about 50 by total weight percent.

3. The synthetic fiber blend of claim 1, wherein the first fiber component is present in the synthetic fiber blend in about 6.7 percent by total weight percent.

4. The synthetic fiber blend of claim 1, wherein the first fiber component is about 100 to about 20,000 denier per filament.

5. The synthetic fiber blend of claim 1, wherein the second fiber component is present in the synthetic fiber blend in amounts ranging from about 50 to about 95 by total weight percent.

6. The synthetic fiber blend of claim 1, wherein the second fiber component is present in the synthetic fiber blend in about 93.3 percent by total weight percent.

7. The synthetic fiber blend of claim 1, wherein the second fiber component is made of one or more nonfibrillating monofilaments of about 350 to about 6000 denier per filament.

8. The synthetic fiber blend of claim 1, wherein the first fiber component has a fiber length of about 19 to about 60 mm and the second fiber component has a fiber length of about 19 to about 60 mm.

9. The synthetic blend of claim 1, wherein the first fiber component and the second fiber component are blended in the absence of a wetting agent.

10. The synthetic blend of claim 1, wherein the monofilaments of the second fiber component, in the absence of a wetting agent, are twisted.

11. The synthetic fiber blend of claim 8, wherein the first fiber component and the second fiber component have about the same fiber length.

12. A synthetic fiber blend for use as reinforcement for cementitious material, comprising:

a first fiber component formed of a homopolymer polypropylene fiber wherein the first fiber component is fibrillated; and

a second fiber component being discrete from the first fiber component and being a copolymer formed of a polypropylene and a high density polyethylene, the second fiber component being a plurality of monofilaments twisted to form a non-interconnected bundle,

the first fiber component being present in the synthetic fiber blend in amounts ranging from about 5 to about 50 by total weight percent, and the second fiber component being present in the synthetic fiber blend in amounts ranging from about 50 to about 95 by total weight percent.

13. The synthetic fiber blend of claim 12, wherein the first fiber component is about 100 to about 20,000 denier per filament, and the second fiber component is about 350 to about 6000 denier per filament.

14. The synthetic fiber blend of claim 12, wherein the first fiber component is a fibrillated fiber having a fiber length of about 19 to about 60 mm and the second fiber component is in the form of nonfibrillating monofilaments having a fiber length of about 19 to about 60 mm.

15. The synthetic fiber blend of claim 12, wherein the first fiber component is present in the synthetic blend in about 6.7 total weight percent and second fiber component is present in the synthetic fiber blend in about 93.3 percent by total weight percent.

16. The synthetic fiber blend of claim 12 wherein the second fiber is formed of about 70 to 80 percent by weight polypropylene and about 20 to 30 percent by weight high density polyethylene.

17. The synthetic blend of claim 12, wherein the first fiber component and the second fiber component are blended in the absence of a wetting agent.

18. The synthetic blend of claim 12, wherein the monofilaments of the second fiber component, in the absence of a wetting agent, are twisted.

19. A synthetic fiber blend for use as reinforcement for cementitious material, comprising:

a first fiber component formed of a homopolymer material wherein the first fiber component is fibrillated; and

a second fiber component being discrete from the first fiber component and being a copolymer formed of a polypropylene and a high density polyethylene, the second fiber component being a plurality of monofilaments twisted to form a non-interconnected bundle.

20. The synthetic blend of claim 19, wherein the first fiber component is added to the synthetic blend in amounts ranging from about 5 to about 50 weight percent, and the second fiber component is added to the synthetic blend in amounts ranging from about 95 weight percent.

21. The synthetic blend of claim 19, wherein the second fiber component is twisted to form the non-interconnected bundle in the absence of a wetting agent.

22. A synthetic fiber blend for use as reinforcement for cementitious material, comprising:

a first fiber component formed from a homopolymer of polypropylene and composed of fibers in fibrillated form; and

a second fiber component, discrete from the first fiber component, formed from a copolymer of polypropylene and high density polyethylene, and composed of bundles of monofilaments that have been twisted.