Lyocell fibers with anti-microbial activity
Meltblown lyocell fibers are disclosed which show a high degree of antimicrobial activity against E. coli and C. albicans . The fibers are prepared by adding inorganic and organic compounds to the NMNO dope prior to spinning. The additives are uniformly distributed throughout the fiber cross section and longitudinal sections show relatively smooth or grainy, rough surfaces depending on the additive used.
1 . Meltblown lyocell fibers comprising at least one antimicrobial agent, said antimicrobial agent uniformly distributed throughout the cross section of said fiber,
said fibers further comprising four percent to eighteen by weight hemicellulose in said fibers and,
an ISO brightness of at least 35.
2 . The fibers of claim 1 wherein said antimicrobial agent is an inorganic compound.
3 . The fibers of claim 2 wherein the antimicrobial agent is selected from the group consisting of compounds containing one or more of copper, silver, zinc, potassium, magnesium, calcium or combinations thereof.
4 . The fibers of claim 3 wherein the antimicrobial agent is a compound containing zinc.
5 . The fibers of claim 3 wherein the antimicrobial agent is a compound containing silver.
6 . The fibers of claim 3 wherein the antimicrobial agent is a compound containing calcium.
7 . The fibers of claim 1 wherein said antimicrobial agent is an organic compound.
8 . The fibers of claim 7 wherein said antimicrobial agent is an organic compound containing silver.
9 . The fibers of claim 8 wherein the fibers contain from about 5 to about 1000 ppm silver.
10 . The fibers of claim 2 wherein the fibers contain from about 0.1 percent to about 40 percent by weight of the antimicrobial agent.
11 . The fibers of claim 1 wherein the fibers contain from about 10 percent to about 25 percent by weight of the antimicrobial agent.
12 . The fibers of claim 1 wherein the fibers contain from about 15 percent to about 20 percent by weight of the antimicrobial agent.
13 . The fibers of claim 1 wherein the birefringence is at least 0.020.
14 . The fibers of claim 1 wherein the fiber diameter is from about 2 to about 50 microns.
15 . The fibers of claim 1 wherein the fiber diameter is from about 5 to about 35 microns.
15 . The fibers of claim 1 wherein the fiber diameter is from about 10 to about 20 microns.
16 . The fibers of claim 1 wherein the reduction in E. Coli colony forming units is at least ninety five percent relative to a control at twenty four hours.
17 . The fibers of claim 1 wherein the reduction in C. Albicans colony forming units is at least ninety five percent relative to a control at four hours.