Filter felts and bag filters comprising blends of fibers derived from diamino diphenyl sulfone and heat resistant fibers

1. A bag filter containing a filter felt the bag filter having a tubular section, one closed end and one open end, wherein the filter felt is a nonwoven felt and forms at least the tubular section of the bag filter,

wherein the filter felt comprises an intimate staple fiber blend of

a) 20 to 75 parts by weight polymeric staple fiber of a polymer or copolymer consisting of sulfone amine monomer reacted with at least one acid monomer, the sulfone amine monomer selected from the group consisting of 4,4′ diaminodiphenyl sulfone, 3,3′ diaminodiphenyl sulfone, and mixtures thereof; and

b) 25 to 80 parts by weight of a heat resistant staple fiber selected from the group consisting of meta-aramid fiber, acrylic fiber, polyphenylene sulfide fiber, and para-aramid fiber; based on the 100 parts by weight of the polymeric fibers and heat resistant fibers in the felt.

2. The bag filter of claim 1 wherein the polymeric staple of the filter felt fiber is present in an amount of 50 to 70 parts by weight.

3. The bag filter of claim 1 wherein the heat resistant staple fiber of the filter felt is present in an amount of 30 to 50 parts by weight.

4. The bag filter of claim 1 wherein the filter felt is in the form of a needlepunched felt.

5. The bag filter of claim 1 wherein the filter felt is in the form of a spunlaced felt.

6. The bag filter of claim 1 wherein the denier per filament of the polymeric staple fiber or the heat resistant staple fiber of the filter felt is from 1.5 to 3.0 (1.7 to 3.3 dtex per filament).

7. The bag filter of claim 1 having a basis weight of from 8 to 16 ounces per square yard (270 to 540 grams per square meter) for the filter felt.

8. The bag filter of claim 7 having a basis weight of from 12 to 14 ounces per square yard (400 to 480 grams per square meter) for the filter felt.

9. A bag filter containing a filter felt the bag filter having a tubular section, one closed end and one open end, wherein the filter felt is a nonwoven felt and forms at least the tubular section of the bag filter,

wherein the filter felt comprises an intimate staple fiber blend of a) 20 to 75 parts by weight polymeric staple fiber of a polymer or copolymer consisting of a mixture of sulfone amine monomer and aromatic amine monomer reacted with at least one acid monomer,

the sulfone amine monomer selected from the group consisting of 4,4′ diaminodiphenyl sulfone, 3,3′ diaminodiphenyl sulfone, and mixtures thereof;

the aromatic amine monomer selected from the group consisting of paraphenylene diamine, metaphenylene diamine, and mixtures thereof; and

b) 25 to 80 parts by weight of a heat resistant staple fiber selected from the group consisting of meta-aramid fiber, acrylic fiber, polyphenylene sulfide fiber, and para-aramid fiber; based on the 100 parts by weight of the polymeric fibers and heat resistant fibers in the felt.

10. The bag filter of claim 9 wherein at least 80 mole percent of the polymer or copolymer used in the polymeric staple fiber is derived from the sulfone amine monomer in the filter felt.

11. The bag filter of claim 9 wherein the polymeric staple fiber is present in an amount of 50 to 70 parts by weight in the filter felt.

12. The bag filter of claim 9 wherein the heat resistant staple fiber is present in an amount of 30 to 50 parts by weight in the filter felt.

13. The bag filter of claim 9 wherein the filter felt is in the form of a needlepunched felt.

14. The filter felt bag filter of claim 9 wherein the filter felt is in the form of a spunlaced felt.

15. The bag filter of claim 9 wherein the denier per filament of the polymeric staple fiber or the heat resistant staple fiber is from 1.5 to 3.0 (1.7 to 3.3 dtex per filament) of the filter felt.

16. The bag filter of claim 9 having a basis weight of from 8 to 16 ounces per square yard (270 to 540 grams per square meter) of the filter felt.

17. The bag filter of claim 16 having a basis weight of from 12 to 14 ounces per square yard (400 to 480 grams per square meter) of the filter felt.