Filter media including flame retardant fibers
Filter media including a filtration layer comprising fibers (e.g., synthetic fibers) comprising a flame retardant and related components, systems, and methods associated herewith are provided. In some embodiments, a filtration layer may include a nonwoven web (e.g., wet-laid nonwoven web) comprising fibers including a certain flame retardant that has a relatively low concentration of or is substantially free of certain undesirable and/or toxic components (e.g., halogens). In certain embodiments, the nonwoven web may also comprise a blend of fibers. For instance, in some embodiments, the nonwoven web may also comprise a blend of coarse and fine diameter synthetic fibers that impart beneficial performance properties to the filtration layer. In some embodiments, the filtration layer may be designed to have a desirable flame retardancy (e.g., F1 rating, K1 rating) and performance properties without compromising certain mechanical properties (e.g., pleatability of the media) and/or environmental attributes (e.g., relatively low toxicity). Filter media described herein may be particularly well-suited for applications that involve filtering air, though the media may also be used in other applications.
1. A filter media, comprising:
a flame retardant wet-laid nonwoven web comprising fibers comprising a phosphorus-based flame retardant, wherein the surface average fiber diameter (SAFD) of the flame retardant wet-laid nonwoven web is greater than or equal to about 1 micron and less than or equal to about 25 microns and is measured using the formula:
SAFD
[
in
microns
]
=
4
/
(
SSA
ρ
[
in
g
cm
3
]
)
wherein SSA is the BET surface area of the flame retardant wet-laid nonwoven web in m 2 /g and ρ is the density of the flame retardant wet-laid nonwoven web in g/cm 3 .
2. A filter media, comprising:
a wet-laid nonwoven web comprising flame retardant fibers, wherein the wet-laid nonwoven web comprises less than or equal to about 1500 ppm of total halogens, and wherein the surface average fiber diameter (SAFD) of the wet-laid nonwoven web is greater than or equal to about 1 micron and less than or equal to about 25 microns and is measured using the formula:
SAFD
[
in
microns
]
=
4
/
(
SSA
ρ
[
in
g
cm
3
]
)
wherein SSA is the BET surface area of the wet-laid nonwoven web in m 2 /g and ρ is the density of the wet-laid nonwoven web in g/cm 3 .
3. The filter media of claim 1 , wherein the fibers are synthetic fibers.
4. The filter media of claim 1 , wherein the phosphorus-based flame retardant comprises a phosphate ester, a phosphonate, a phosphine oxide, red phosphorus, an inorganic phosphate, or a derivative thereof.
5. The filter media of claim 1 , wherein the fibers comprise a synthetic polymer.
6. The filter media of claim 5 , wherein a backbone of the synthetic polymer comprises a flame retardant.
7. The filter media of claim 5 , wherein one or more pendant groups of the synthetic polymer comprises a flame retardant.
8. The filter media of claim 1 , wherein the phosphorus-based flame retardant is distributed throughout the fiber.
9. The filter media of claim 1 , wherein the weight percentage of fibers comprising the phosphorus-based flame retardant in the flame retardant wet-laid nonwoven web is greater than or equal to about 20 wt. % and less than or equal to about 99 wt. %.
10. The filter media of claim 1 , wherein the flame retardant wet-laid nonwoven web comprises less than 1 wt. % glass fibers.
11. The filter media of claim 1 , wherein the flame retardant wet-laid nonwoven web has a F1 rating as measured according to DIN 53438.
12. The filter media of claim 1 , wherein the flame retardant wet-laid nonwoven web has a K1 rating as measured according to DIN 53438.
13. The filter media of claim 1 , wherein the fibers comprising the phosphorus-based flame retardant have an average length of less than or equal to 12 mm.
14. A filter media, comprising:
a flame retardant nonwoven web comprising fibers comprising a phosphorus-based flame retardant having a length of less than or equal to about 30 mm, wherein the flame retardant nonwoven web has a thickness of less than or equal to about 1 mm and the flame retardant nonwoven web has an air permeability of greater than or equal to about 20 CFM and less than or equal to about 800 CFM, and wherein the surface average fiber diameter (SAFD) of the flame retardant nonwoven web is greater than or equal to about 1 micron and less than or equal to about 25 microns and is measured using the formula:
SAFD
[
in
microns
]
=
4
/
(
SSA
ρ
[
in
g
cm
3
]
)
wherein SSA is the BET surface area of the flame retardant nonwoven web in m 2 /g and ρ is the density of the flame retardant nonwoven web in g/cm 3 .
15. A filter media, comprising:
a nonwoven web comprising flame retardant fibers having a length of less than or equal to about 30 mm, wherein the nonwoven web comprises less than or equal to about 1500 ppm of total halogens, the nonwoven web has a thickness of less than or equal to about 1 mm, and the nonwoven web has an air permeability of greater than or equal to about 20 CFM and less than or equal to about 800 CFM, and the surface average fiber diameter (SAFD) of the nonwoven web is greater than or equal to about 1 micron and less than or equal to about 25 microns and is measured using the formula:
SAFD
[
in
microns
]
=
4
/
(
SSA
ρ
[
in
g
cm
3
]
)
wherein SSA is the BET surface area of the nonwoven web in m 2 /g and ρ is the density of the nonwoven web in g/cm 3 .
16. The filter media of claim 15 , wherein the fibers are synthetic fibers.
17. A method of manufacturing a non-woven web, comprising:
providing fibers comprising a phosphorus-based flame retardant; and
forming a non-woven web using a wetlaid process,
wherein the surface average fiber diameter (SAFD) of the non-woven web is greater than or equal to about 1 micron and less than or equal to about 25 microns and is measured using the formula:
SAFD
[
in
microns
]
=
4
/
(
SSA
ρ
[
in
g
cm
3
]
)
wherein SSA is the BET surface area of the non-woven web in m 2 /g and ρ is the density of the non-woven web in g/cm 3 .
18. The filter media of claim 17 , wherein the fibers are uncrimped.