Bi-component fiber and filter media including bi-component fibers
View Patent ↗A bi-component fiber is provided. The bi-component fiber includes a sheath formed of polyphenylene sulfide (PPS) and a core formed of a high glass transition polyester. A PPS material of the sheath has a higher melting point than a high glass transition polyester material of the core. The core is at least partially crystallized whereby the high glass transition polyester material of the core effectively has a higher softening point than a softening point of the PPS material of the sheath.
1. A bi-component fiber, comprising:
a sheath formed of polyphenylene sulfide (PPS); and
a core formed of a high glass transition polyester,
a PPS material of the sheath having a higher melting point than a high glass transition polyester material of the core, and
the core being at least partially crystallized whereby the high glass transition polyester material of the core effectively has a higher softening point than a softening point of the PPS material of the sheath.
2. The bi-component fiber according to claim 1 , wherein the high glass transition polyester material of the core comprises a polyester derived from cyclohexanedimethanol and terephthalic acid.
3. The bi-component fiber according to claim 1 , wherein the core comprises inorganic filler material.
4. The bi-component fiber according to claim 1 , wherein the core comprises carbonate additives.
5. A filter medium, comprising:
a plurality of bi-component fibers, each bi-component fiber including a sheath formed of polyphenylene sulfide (PPS) and a core formed of a high glass transition polyester, a PPS material of the sheath having a higher melting point than a high glass transition polyester material of the core, and the core being at least partially crystallized whereby the high glass transition polyester material of the core effectively has a higher softening point than a softening point of the PPS material of the sheath; and
a porous membrane to which the plurality of bi-component fibers is fixedly attached.
6. The filter medium according to claim 5 , wherein the high glass transition polyester material of the core of each bi-component fiber comprises a polyester derived from cyclohexanedimethanol and terephthalic acid.
7. The filter medium according to claim 5 , wherein the core of each bi-component fiber comprises inorganic filler material.
8. The filter medium according to claim 7 , wherein the inorganic filler material comprises at least one or more of titanium oxide, calcium carbonate and glass.
9. The filter medium according to claim 5 , wherein the porous membrane comprises polytetrafluoroethylene (PTFE).
10. The filter medium according to claim 5 , wherein the plurality of bi-component fibers are disposed to form a felt material, which is laminated to the porous membrane.
11. The filter medium according to claim 10 , wherein the felt material is needlepunched.
12. The filter medium according to claim 5 , further comprising a woven scrim disposed among the plurality of bi-component fibers.
13. A filter element for use in filtering flue gas from a coal-fired boiler, the filter element comprising the filter medium according to claim 5 .
14. A method of forming a filter medium, comprising:
manufacturing a plurality of bi-component fibers, each bi-component fiber including a sheath formed of polyphenylene sulfide (PPS) and a core formed of a high glass transition polyester, a PPS material of the sheath having a higher melting point than a high glass transition polyester material of the core, and the core being at least partially crystallized whereby the high glass transition polyester material of the core effectively has a higher softening point than a softening point of the PPS material of the sheath;
assembling the plurality of bi-component fibers into a felt material; and
laminating the felt material onto a porous membrane.
15. The method according to claim 14 , wherein the manufacturing of the plurality of bi-component fibers comprises delaying a cooling process of each bi-component fiber to crystallize the high glass transition polyester material of the core.
16. The method according to claim 14 , wherein the manufacturing of the plurality of bi-component fibers comprises adding inorganic filler material to the high glass transition polyester material of the core.
17. The method according to claim 16 , wherein the inorganic filler material comprises at least one or more of titanium oxide, calcium carbonate and glass.
18. The method according to claim 14 , wherein the assembling comprises needlefelting.
19. The method according to claim 14 , further comprising disposing a woven scrim among the plurality of bi-component fibers.
20. The method according to claim 14 , wherein the laminating the felt material onto the porous membrane comprises a thermal lamination process.
21. A felt, comprising:
a plurality of bi-component fibers, each bi-component fiber comprising:
a sheath formed of polyphenylene sulfide (PPS); and
a core formed of a high glass transition polyester,
a PPS material of the sheath having a higher melting point than a high glass transition polyester material of the core, and
the core being at least partially crystallized whereby the high glass transition polyester material of the core effectively has a higher softening point than a softening point of the PPS material of the sheath.
22. The felt according to claim 21 , wherein the high glass transition polyester material of the core of each bi-component fiber comprises a polyester derived from cyclohexanedimethanol and terephthalic acid.
23. The felt according to claim 21 , wherein the core of each bi-component fiber comprises inorganic filler material.
24. The felt according to claim 21 , further comprising a woven scrim disposed among the plurality of bi-component fibers.