Electrets and compounds useful in electrets
An electret filter media that includes a thermoplastic resin and a compound of the formula Y 2 -A(R 1 ) n —Y 1 , where A is benzene, naphthalene or anthracene, Y 1 and Y 2 are each independently R 2 -R 3 , R 2 is an ester linking group or an amide linking group, R 3 is an alkyl group having from 10 to 22 carbon atoms, R 1 is R 2 -R 3 where R 2 and R 3 are each independently as defined above, and when A is benzene, n is from 0 to 4, when A is naphthalene, n is from 0 to 6, and when A is anthracene, n is from 0 to 8.
1. An electret filter media comprising a fibrous web that comprises fibers comprising:
thermoplastic resin, and
a compound of the formula
Y 2 -A(R 1 ) n —Y 1 (I)
where A is benzene, naphthalene or anthracene,
Y 1 and Y 2 are each independently R 2 -R 3 ,
R 2 is an ester linking group or an amide linking group,
R 3 is a straight chain alkyl group having from 10 to 22 carbon atoms,
R 1 is R 2 -R 3 , where R 2 and R 3 are each independently as defined above, and
when A is benzene, n is from 0 to 4,
when A is naphthalene, n is from 0 to 6, and
when A is anthracene, n is from 0 to 8.
2. The electret filter media of claim 1 , wherein A is benzene.
3. The electret filter media of claim 2 , wherein R 2 is —CONH, —NHCO, —OCO or —COO.
4. The electret filter media of claim 3 , wherein R 3 is an alkyl group having from 12 to 22 carbon atoms.
5. The electret filter media of claim 3 , wherein n is 1.
6. The electret filter media of claim 3 , wherein n is 1, and R 1 , Y 1 and Y 2 are located meta to each other.
7. The electret filter media of claim 3 , wherein n is 0 and Y 1 and Y 2 are located para to each other.
8. The electret filter media of claim 1 , wherein A is naphthalene.
9. The electret filter media of claim 8 , wherein R 2 is —CONH—, —NHCO—, —OCO— or —COO—.
10. The electret filter media of claim 8 , wherein R 3 is an alkyl group having from 12 to 22 carbon atoms.
11. The electret filter media of claim 8 , wherein n is 0, Y 1 is located at the 2 position on naphthalene, and Y 2 is located at the 6 position on naphthalene.
12. The electret filter media of claim 8 , wherein n is 1.
13. The electret filter media of claim 1 , wherein the compound of formula (I) is selected from the group consisting of:
benzene-1,3,5-tricarboxylic acid tris-octadecylamide;
p-phenylene distearylamide;
distearyl-2,6-naphthalenedicarboyxlate; and
2,6-naphthalene distearamide.
14. The electret filter media of claim 1 , wherein the thermoplastic resin is selected from the group consisting of polycarbonate, polyolefin, polyester, halogenated polyvinyl, polystyrene, or a combination thereof.
15. The electret filter media of claim 1 , wherein the thermoplastic resin is selected from the group consisting of polypropylene, poly-(4-methyl-1-pentene), or a combination thereof.
16. The electret filter media of claim 1 , wherein the fibers include meltblown microfibers.
17. An air filter that comprises the electret filter media of claim 1 .
18. A respirator that comprises at least one layer of filter media that includes the electret filter media of claim 1 .
19. A vehicle ventilation system that comprises at least one layer of filter media that includes the electret filter media of claim 1 .