Rubber compound reinforced with alternative fibers

1 . A rubber compound for use in a stator, the rubber compound comprising:

a fiber reinforcement, the fiber reinforcement including a plurality of fibers, wherein fibers in the fiber reinforcement create a grain direction in which “with the grain” is generally orthogonal to “across the grain”, wherein the rubber compound has a first value for 25% tensile Modulus “across the grain” and a second value for 25% tensile Modulus “with the grain”, wherein the first value is at least 10% lower than the second value;

wherein the fiber reinforcement includes a fiber loading of greater than 1.0 phr of fibers;

wherein the rubber compound has a 25% tensile Modulus of greater than 400 psi “across the grain” and a 50% tensile Modulus of greater than 700 psi “across the grain”; and

wherein the fiber reinforcement includes fibers made from at least one material type selected from the group consisting of:

(a) meta-aramid;

(b) para-aramid;

(c) polyester;

(d) polyamide;

(e) cotton;

(f) rayon; and

(g) glass.

2 . The rubber compound of claim 1 , in which the fiber reinforcement includes at least some fibrillated fibers.

3 . The rubber compound of claim 2 , in which the fibrillated fibers have surface areas in a range of 2 m 2 /g to 20 m 2 /g.

4 . The rubber compound of claim 2 , in which the fibrillated fibers have surface areas in a range of 7 m 2 /g to 11 m 2 /g.

5 . The rubber compound of claim 1 , in which the fiber reinforcement includes at least some short chop fibers.

6 . The rubber compound of claim 5 , in which the short chop fibers have lengths in a range of 0.1 mm to 10.0 mm.

7 . The rubber compound of claim 1 , in which at least some of the fibers have a Modulus greater than 2.0 GPa.

8 . The rubber compound of claim 1 , in which at least some of the fibers have a Modulus in a range between 2.0 GPa and 4.0 GPa.

9 . The rubber compound of claim 1 , in which at least some of the fibers have a Modulus in a range between 2.0 GPa and 14.0 GPa.

10 . The rubber compound of claim 1 , in which the fiber reinforcement includes the fiber loading in a range from 1.0 phr of fibers to 20.0 phr of fibers.

11 . The rubber compound of claim 1 , in which the fiber reinforcement includes the fiber loading in a range from 1.0 phr of fibers to 6.0 phr of fibers.

12 . A rubber compound for use in a stator, the rubber compound comprising:

a fiber reinforcement, the fiber reinforcement including a plurality of fibers, wherein fibers in the fiber reinforcement create a grain direction in which “with the grain” is generally orthogonal to “across the grain”, wherein the rubber compound has a first value for 25% tensile Modulus “across the grain” and a second value for 25% tensile Modulus “with the grain”, wherein the first value is at least 10% lower than the second value;

wherein the fiber reinforcement includes a fiber loading of greater than 1.5 phr of fibers;

wherein the rubber compound has a 25% tensile Modulus of greater than 400 psi “across the grain” and a 50% tensile Modulus of greater than 700 psi “across the grain”; and

wherein the fiber reinforcement includes fibers made from at least one material type selected from the group consisting of:

(a) meta-aramid;

(b) para-aramid;

(c) polyester;

(d) polyamide;

(e) cotton;

(f) rayon; and

(g) glass.

13 . The rubber compound of claim 12 , in which the fiber reinforcement includes at least some fibrillated fibers.

14 . The rubber compound of claim 13 , in which the fibrillated fibers have surface areas in a range of 2 m 2 /g to 20 m 2 /g.

15 . The rubber compound of claim 12 , in which the fiber reinforcement includes at least some short chop fibers.

16 . The rubber compound of claim 15 , in which the short chop fibers have lengths in a range of 0.1 mm to 10.0 mm.

17 . The rubber compound of claim 12 , in which at least some of the fibers have a Modulus greater than 2.0 GPa.

18 . A rubber compound for use in a stator, the rubber compound comprising:

a fiber reinforcement, the fiber reinforcement including a plurality of fibers, wherein fibers in the fiber reinforcement create a grain direction in which “with the grain” is generally orthogonal to “across the grain”, wherein the rubber compound has a first value for 25% tensile Modulus “across the grain” and a second value for 25% tensile Modulus “with the grain”, wherein the first value is at least 10% lower than the second value;

wherein the fiber reinforcement includes a fiber loading of greater than 2.0 phr of fibers;

wherein the rubber compound has a 25% tensile Modulus of greater than 400 psi “across the grain” and a 50% tensile Modulus of greater than 700 psi “across the grain”; and

wherein the fiber reinforcement includes fibers made from at least one material type selected from the group consisting of:

(a) meta-aramid;

(b) para-aramid;

(c) polyester;

(d) polyamide;

(e) cotton;

(f) rayon; and

(g) glass.

19 . The rubber compound of claim 18 , in which the fiber reinforcement includes at least some fibrillated fibers.

20 . The rubber compound of claim 19 , in which the fibrillated fibers have surface areas in a range of 2 m 2 /g to 20 m 2 /g.

21 . The rubber compound of claim 18 , in which the fiber reinforcement includes at least some short chop fibers.

22 . The rubber compound of claim 21 , in which the short chop fibers have lengths in a range of 0.1 mm to 10.0 mm.

23 . The rubber compound of claim 18 , in which at least some of the fibers have a Modulus greater than 2.0 GPa.