U.S. patent application number 15/754062 was filed with the patent office on 2019-01-10 for fuel water separation filter medium for removing water from water-hydrocarbon emulsions having improved efficiency.
The applicant listed for this patent is AHLSTROM-MUNKSJO OYJ. Invention is credited to Crawford ARRINGTON, Jayden BAE, Andrew GOODBY, Aaron HARMON, Praven JANA, Kevin KIM, Ryan KWON, Jesse SHIM, Ganga VENKATESWARAN, Patrick YEO.
Application Number | 20190009194 15/754062 |
Document ID | / |
Family ID | 56464189 |
Filed Date | 2019-01-10 |
![](/patent/app/20190009194/US20190009194A1-20190110-D00000.png)
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United States Patent
Application |
20190009194 |
Kind Code |
A1 |
GOODBY; Andrew ; et
al. |
January 10, 2019 |
FUEL WATER SEPARATION FILTER MEDIUM FOR REMOVING WATER FROM
WATER-HYDROCARBON EMULSIONS HAVING IMPROVED EFFICIENCY
Abstract
A fuel water separation medium for removing water from
water-hydrocarbon emulsions is provided, wherein the fuel water
separation medium comprises (A) a first layer comprising
nanofibers, and (B) a second layer comprising a fibrous web wherein
the fibrous web comprises cellulosic fibers.
Inventors: |
GOODBY; Andrew; (Sturgis,
KY) ; JANA; Praven; (Bear, DE) ; ARRINGTON;
Crawford; (Mount Juliet, TN) ; VENKATESWARAN;
Ganga; (Worcester, MA) ; HARMON; Aaron;
(Owensboro, KY) ; SHIM; Jesse; (Daegu Metropolitan
City, Daegu, KR) ; KWON; Ryan; (Daegu Metropolitan
City, Daegu, KR) ; KIM; Kevin; (Daegu Metropolitan
City, Daegu, KR) ; BAE; Jayden; (Daegu Metropolitan
City, Daegu, KR) ; YEO; Patrick; (Chuncheon-si,
Gangwon-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AHLSTROM-MUNKSJO OYJ |
Helsinki |
|
FI |
|
|
Family ID: |
56464189 |
Appl. No.: |
15/754062 |
Filed: |
July 14, 2016 |
PCT Filed: |
July 14, 2016 |
PCT NO: |
PCT/EP2016/066769 |
371 Date: |
February 21, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62208659 |
Aug 22, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D 2239/0618 20130101;
D04H 3/03 20130101; B32B 2307/726 20130101; B01D 2239/0654
20130101; B32B 2262/101 20130101; B01D 39/2017 20130101; D04H 3/009
20130101; B32B 5/26 20130101; B32B 2250/20 20130101; B32B 2262/14
20130101; D04H 1/728 20130101; B01D 35/005 20130101; B01D 2239/0631
20130101; B01D 2239/0636 20130101; C10G 31/09 20130101; D10B
2505/04 20130101; B01D 2239/064 20130101; B01D 2239/1216 20130101;
B32B 2250/02 20130101; B01D 2239/1291 20130101; B32B 2262/02
20130101; B01D 2239/025 20130101; B32B 5/022 20130101; B01D 39/18
20130101; D10B 2331/061 20130101; B01D 2239/1233 20130101; D04H
1/4326 20130101; B32B 2262/062 20130101; B01D 39/1623 20130101;
B01D 2239/0681 20130101 |
International
Class: |
B01D 35/00 20060101
B01D035/00; B01D 39/16 20060101 B01D039/16; B01D 39/18 20060101
B01D039/18; B01D 39/20 20060101 B01D039/20; D04H 1/4326 20060101
D04H001/4326; D04H 1/728 20060101 D04H001/728; D04H 3/009 20060101
D04H003/009; D04H 3/03 20060101 D04H003/03 |
Claims
1. A fuel water separation medium for removing water from
water-hydrocarbon emulsions comprising (A) a first layer comprising
nanofibers, (B) a second layer comprising a fibrous web, wherein
the fibrous web comprises cellulosic fibers; wherein the nanofibers
have an average fiber diameter of about 50-350 nm, such as about
100-300 nm; wherein the fuel water separation medium has a basis
weight of about 100-300 g/m.sup.2, such as about 150-300 g/m.sup.2;
wherein the fuel water separation medium is characterized by having
a net change in water removal efficiency measured according to
SAEJ1488 being preferably less than about 10%, more preferably less
than about 5 and wherein the net change in water removal efficiency
is defined as follows: net change in water removal efficiency=water
removal efficiency after 165 min-water removal efficiency after 15
min.
2. The filter medium according to claim 1, wherein the filter
medium is characterized by a TSI aerosol penetration of less than
or equal to about 15%, preferably less than or equal to about 10%,
more preferably less than or equal to about 5%.
3. The filter medium according to any one of claim 1 or 2, wherein
the filter medium is characterized by a mean flow pore size of
about 2-10 microns.
4. The medium according to any of the preceding claims, wherein the
fibrous web of the second layer is a wet-laid fibrous web.
5. The medium according to any of the preceding claims, wherein the
nanofibers are synthetic nanofibers selected from polyethersulfone
(PES); polyacrylonitrile; polyamide (PA) such as nylon; and
fluoropolymer such as polyvinylfluoride (PVDF); and/or mixtures
thereof.
6. The medium according to claim 5, wherein the nanofibers are
polyamide nanofibers or fluoropolymeric nanofibers.
7. The medium according to any of the preceding claims, wherein the
second layer has a basis weight of about 60-250 g/m.sup.2.
8. The medium according to any of the preceding claims, wherein the
second layer has a Gurley stiffness of about 2-15 g.
9. The medium according to any of the preceding claims, wherein the
second layer comprises substantially no glass fibers.
10. The medium according to any of the preceding claims, wherein
the second layer comprises substantially no synthetic fibers.
11. The medium according to any of the preceding claims, wherein
the second layer comprises cellulosic fibers in an amount of at
least about 50% by weight such as at least about 60% by weight or
at least about 80% by weight, based on the total weight of second
layer.
12. The medium according to any of the preceding claims, wherein
the nanofibers of the first layer, which are preferably prepared
from an adhesive, which is preferably used in an amount of about 1
to about 5% by weight, and a polyethersulfone which is preferably
used in an amount of about 95 to about 99% by weight, based on the
total weight of the nanofibers, are electrospun directly onto the
second layer.
13. The medium according to any of the preceding claims, wherein
the first layer consists essentially of nanofibers.
14. The medium according to any of the preceding claims, wherein
the second layer includes substantially no fibrillated fibers such
as fibrillated cellulosic fibers.
15. The medium according to any of the preceding claims, wherein
the second layer does not comprise a water repellant additive.
16. The medium according to any of the preceding claims, wherein
the second layer is on a downstream side of the first layer.
17. The medium according to any one of claims 1-15, wherein the
second layer is on an upstream side of the first layer.
18. The medium according to any of the preceding claims, wherein
the medium does not include a protective fine fiber layer as third
layer on an upstream side of the first layer.
19. The medium according to any one of claims 1-17, wherein the
medium comprises a third layer on an upstream side of the first
layer, the third layer being a protective fine fiber layer.
20. The medium according to any one of claim 18 or 19, wherein the
protective fine fiber layer comprises, or consists of, synthetic
fibers such as synthetic fibers selected from polyester,
polyethylene terephthalate, polyolefin, polybutylene terephthalate
and/or polyamide.
21. The medium according to claims 18-20, wherein the third layer
comprises a spunbond fiber sub-layer, such as a PET layer having
preferably a basis weight of about 8 to about 30 g/m.sup.2, and a
meltblown fiber sub-layer, such as a PET layer having preferably a
basis weight of about 25 to about 80 g/m.sup.2.
22. The medium according to claims 18-21, wherein the third layer
has a basis weight of about 10 to about 200 g/m.sup.2 such as about
15 to about 100 g/m.sup.2.
23. The medium according to any of claims 19-22, wherein the second
layer is on a downstream side of the first layer and the third
layer is on an upstream side of the first layer.
24. The medium according to any of claims 19-22, the second layer
is on an upstream side of the first layer and the third layer is on
an upstream side of the second layer.
25. The medium according to any of the preceding claims, wherein
the medium comprises an adhesive layer between the first and the
second layer.
26. The medium according to any of claims 19-25, wherein the medium
comprises an adhesive layer between the first and the third
layer.
27. The medium according to any one of claims 25-26, wherein said
adhesive layer(s) comprise(s) an adhesive selected from
polyurethane; acrylate; PVA; polyolefin ethylene co-polymer; and/or
rubber-based adhesive.
28. The filter medium according to any of the preceding claims,
consisting, or consisting essentially, of (A) the first layer; (B)
the second layer; (C) optionally the third layer; (D1) optionally
the adhesive layer between the first and the second layer; and (D2)
optionally the adhesive layer on a downstream side of the third
layer, if present.
29. The filter medium according to any one of claims 1-27,
consisting, or consisting essentially, of (A') the first layer;
(B') the second layer; (C') optionally two of the third layers;
(D1') optionally the adhesive layer between the first and the
second layer; and (D2') optionally the adhesive layer on an
upstream surface of the second layer.
30. The medium according to any of the preceding claims, wherein
the filter medium is characterized by a basis weight of about
150-300 g/m.sup.2 when tested according to TAPPI Standard T 410
om-02.
31. The medium according to any of the preceding claims, wherein
the filter medium is characterized by an overall fuel-water
separation efficiency of at least about 55% after 15 minutes when
tested according to SAEJ1488.
32. The medium according to any of the preceding claims, wherein
the filter medium is characterized by an overall fuel-water
separation efficiency of at least about 60% after 165 minutes when
tested according to SAEJ1488.
33. The medium according to any of the preceding claims, wherein
the filter medium is characterized by a TSI resistance to flow of
about 5-75 mm H.sub.2O.
34. The medium according to any of the preceding claims, wherein
the filter medium is characterized by an air permeability of about
3-20 cfm when tested according to TAPPI Standard T 251 cm-85.
35. The medium according to any of the preceding claims, wherein
the filter medium is characterized by a leakage-corrected Frazier
of 3-20 cfm when tested according to TAPPI Standard T 251
cm-85.
36. Process for the preparation of the medium according to any of
claims 1 to 35, the process comprising the steps of providing a
first homogeneous slurry; supplying the first slurry onto a
dewatering screen to form a first deposit; removing the water from
the deposit to form a wet fibrous web; (d) drying the wet fibrous
web while heating to form the second layer; optionally saturating
the thus obtained second layer with a binder resin; optionally
coating of a first adhesive layer on top of the thus obtained
second layer; applying the first layer on top of the second layer
or on top of the first adhesive layer coated onto the second layer,
wherein the applying is preferably performed using electrospinning;
optionally coating of a second adhesive layer (i) on top of the
first layer or (ii) on top of the second layer; and optionally
applying the third layer (iii) on top of the first layer, (iv) on
top of the second adhesive layer coated onto the first layer, if
present, (v) on top of the second layer or (vi) on top of the
second adhesive layer coated onto the second layer, if present;
wherein the first slurry comprises water and cellulosic fibers.
37. Process of claim 36, wherein the applying is performed by
meltblowing a first fine fiber layer and spunbonding a second fine
fiber layer on top of the first fine fiber layer.
38. A fuel water separation filter medium for removing water from
water-hydrocarbon emulsions which is obtainable by the process
according to claim 36 or 37.
39. A fuel water separator for removing water from
water-hydrocarbon emulsions comprising the medium according to any
of claims 1 to 35 and 38.
40. The fuel water separator according to claim 39, wherein the
filter medium is pleated.
41. The fuel water separator according to any one of claims 39-40,
wherein the filter medium is corrugated.
42. The fuel water separator according to any one of claims 39-41,
wherein the filter medium includes a wire mesh supporting layer
co-pleated with the filter medium.
43. The fuel water separator according to any one of claims 39-41,
wherein the filter medium does not include a wire mesh supporting
layer co-pleated with the filter medium.
44. Use of the medium according to any of claims 1 to 35 and 38 or
of the fuel water separator according to claims 39-43 for
separating water from water-hydrocarbon emulsions.
Description
TECHNICAL FIELD
[0001] The present invention relates to a novel fuel water
separation medium for removing water from water-hydrocarbon
emulsions, a process for the preparation of the medium, a fuel
water separator including the medium and the use of the medium for
removing water from water-hydrocarbon emulsions.
BACKGROUND
[0002] There is an increasing demand for filter media that
efficiently remove emulsified water from fuel. Specifically, an
effectual fuel-water separation in new (bio-)diesel and gasoline
engine systems requires media that are efficient in terms of water
removal in order to avoid the known problems associated with a high
amount of emulsified water in fuel. For instance, high amounts of
water may considerably affect the performance of the carburetor,
the fuel injection system and the engine itself due to lack of
lubrication and/or corrosion protection caused by the water
contamination. Ultimately, water contamination may result in
increased wear and rust in the fuel system. Moreover, a blockage or
damage of the carburetor and/or the fuel pump may occur.
[0003] In addition to increasingly stricter emission regulations,
there is also an increasing demand for smaller filters without
considerably sacrificing the achieved water removal efficiency,
thereby saving space/weight and consequently fuel. Less fuel
consumption results in less carbon dioxide emission and is
therefore desirable in order to meet the vehicle emission
regulations.
[0004] Some filter media of the prior art are saturated with water
repellant additives for achieving a sufficiently high fuel-water
separation efficiency, since these additives enhance the
coalescence of water drops during the filtering process.
[0005] Usually, these water repellant additives are silicone or
fluorohydrocarbons which might not be desirable for environmental
reasons.
[0006] Known fuel water separator filter media typically contain a
high percentage of synthetic fibers, such as meltblown synthetic
fibers, or even consist of synthetic fibers only. However, these
filter media are not pleateable or self-supporting as such,
particularly when working under the harsh conditions in connection
with a combustion engine. As a result, these media have to be
co-pleated and reinforced with some sort of additional mechanical
support layer, such as a plastic or wire mesh backing. Further,
media made with high levels of synthetic fiber typically tend to
exhibit drape and they lack sufficient stiffness and rigidity
causing the pleats to collapse without an additional support. A
100% synthetic media as disclosed in the prior art cannot maintain
a grooving pattern like corrugation or a pleated structure due to
the thermal and mechanical properties of the synthetic fibers.
However, grooving patterns are typically important for increasing
the surface of filter media, thereby being able to provide the
desired high fuel-water removal efficiency of the filter media.
[0007] Another issue to be addressed is that customers desire a
longer service interval for filter media. This may be achieved when
providing fuel water separation media that are able to remove water
from water-fuel emulsions over a long period of time and with a
high efficiency. Hence, a considerable loss of water removal
efficiency over time due to e.g. clogging of the filter or wear is
disadvantageous.
[0008] It is thus an objective of the present invention to provide
an improved filter medium for water removal from water-fuel
emulsions which addresses the above issues.
SUMMARY OF THE INVENTION
[0009] This summary is not an extensive overview of the present
invention. It is neither intended to identify key elements of the
invention nor to delineate the scope of the invention. The
following summary merely presents some concepts of the present
invention in a simplified form as a prelude to a more detailed
description of exemplifying embodiments of the present
invention.
[0010] The present invention relates to a fuel water separation
medium for removing water from water-hydrocarbon emulsions
comprising (A) a first layer comprising nanofibers; and (B) [0011]
a second layer comprising a fibrous web wherein the fibrous web
comprises cellulosic fibers. The nanofibers have an average fiber
diameter of about 50-350 nm, such as about 100-300 nm, The fuel
water separation medium has a basis weight of about 100-300
g/m.sup.2, such as about 150-300 g/m.sup.2, and is characterized by
having a net change in water removal efficiency of preferably less
than about 10%, more preferably less than about 5%. The net change
in water removal efficiency is defined as the difference between
the water removal efficiency measured after 165 min and after 15
min according to SAEJ1488.
[0012] Without wishing to be bound by any particular theory, the
Applicant surprisingly observed that by providing the inventive
fuel water separation medium including, in combination: [0013] a
specific layer comprising nanofibers, wherein the nanofibers have a
specific average fiber diameter; and [0014] a specific fibrous web
comprising cellulosic fibers; the fuel water separation medium also
having: [0015] a specific basis weight of about 100-300 gsm
(g/m.sup.2); a better balance of the fuel water separation
performance in terms of both water removal efficiency and long term
effect may be achieved.
DETAILED DESCRIPTION OF THE INVENTION
General Definitions
[0016] The verbs "to comprise" and "to include" are used herein as
open limitations that neither exclude nor require the existence of
un-recited features.
[0017] The term "consisting essentially of" has the meaning that
specific further component(s), which do not materially affect the
essential characteristics of the layer or medium in question, may
be present.
[0018] The features recited in depending claims are freely
combinable unless otherwise explicitly stated.
[0019] Furthermore, it is to be understood that the use of "a" or
"an", i.e. a singular form, used herein does not exclude the plural
form.
[0020] Unless stated otherwise, all percentages are expressed as
percentages by weight.
[0021] Unless otherwise indicated, the unit "um" corresponds to
".mu.m" or micron(s).
[0022] Within the framework of the present description and of the
following claims, "cellulose fibers" or "cellulosic fibers"
comprise naturally occurring cellulosic material such as Northern
bleached softwood kraft pulp (NBSK), Southern bleached softwood
kraft pulp (SBSK) and hardwood pulps, such as Eucalyptus pulp.
[0023] "Synthetic Fibers" are manmade fibers including, but not
limited to, thermoplastic fibers (such as polyether sulfone,
polyester, PET, polyamide, polyvinylidene fluoride, polybutylene
terephthalate), glass fibers and regenerated cellulose fibers.
[0024] Within the framework of the present description and of the
following claims, "nanofibers" are fibers having a diameter less
than 1 um or 1 micron (1000 nm), particularly 50-350 nm such as
100-300 nm, The nanofibers are formed according to known methods
such as via an electrospinning process using suitable polymeric
material(s). In this disclosure, nanofibers preferably are formed
from thermoplastic polymeric materials including, but not limited
to, polyether sulfone (PES), polyamide (PA) such as nylon,
fluoropolymers such as e.g. polyvinylidene fluoride (PVDF),
polyacrylonitrile, polyamide, particularly nylon, or PVDF.
[0025] A "fluoropolymer" is a fluorocarbon-based polymer which
typically has a high resistance to solvents, acids, and bases.
Suitable fluoropolymers are PVF (polyvinylfluoride); PVDF
(polyvinylidene fluoride); PTFE (polytetrafluoroethylene); PCTFE
(polychlorotrifluoroethylene); PFA, MFA (perfluoroalkoxy polymer);
FEP (fluorinated ethylene-propylene); SETFE
(polyethylenetetrafluoroethylene); ECTFE
(polyethylenechlorotrifluoroethylene); FFPM/FFKM (perfluorinated
Elastomer); FPM/FKM (fluorocarbon
[chlorotrifluoroethylenevinylidene fluoride]); FEPM
(fluoroelastomer [tetrafluoroethylene-propylene]); PFPE
(perfluoropolyether); PFSA (perfluorosulfonic acid); and/or
perfluoropolyoxetane.
[0026] A "fibrous web" as used herein includes a "nonwoven" or a
"paper" and is a manufactured sheet or web of directionally or
randomly oriented fibers bonded by friction, cohesion or adhesion.
The fibers may be staple or continuous/substantially continuous or
formed in situ and may be of natural or man-made materials.
[0027] Within the framework of the present description and of the
following claims, a "fine fiber layer" may comprise one or more
fiber layer(s) that comprises continuous/substantially continuous
fibers and may be of natural or man-made materials.
[0028] "Staple fibers" are short cut fibers that may be typically
not longer than about 45 mm.
[0029] "Continuous fibers" are long fibers or filaments that may be
typically longer than about 45 mm. The term "substantially
continuous fibers" includes continuous fibers and fibers which
might have been broken during formation and/or use.
[0030] "Resins" or "binder resins" used in the inventive media may
comprise phenolic, acrylic and epoxy resins. Resins can be applied
or coated onto the substrate by any means know in the art. The
resins can be applied to one side or both sides. The physical
properties of the inventive media can be evaluated after it has
been saturated and dried (SD) as well as after it has been
saturated, dried and cured (SDC). The step of drying removes the
solvent without crosslinking the resin.
[0031] An "adhesive" or "glue" is a chemical compound that assists
in holding together the specific layers of the medium such as the
nanofiber layer to the fibrous web and/or the fine fiber layer, if
present. The adhesive or glue is present in the form of a partial
layer between the layers that shall be hold together.
[0032] "Corrugations" (used interchangeably with "grooves" or
"grooving") are added to a (preferably resin saturated) media in
the machine direction to provide support for pleated media in the
finished filter element.
[0033] The term "substantially no glass fibers" means that no glass
fibers, i.e. 0% by weight of glass fibers, are present in the
corresponding layer, based on the total weight of the corresponding
layer.
[0034] The term "substantially no synthetic fibers" means that less
than 10% by weight, more preferably less than 5% by weight, most
preferably 0% by weight, of synthetic fibers are present in the
corresponding layer, based on the total weight of the corresponding
layer.
[0035] The term "substantially no fibrillated fibers" means that
less than 10% by weight, more preferably less than 5% by weight,
most preferably 0% by weight, of fibrillated fibers are present in
the corresponding layer, based on the total weight of the
corresponding layer.
[0036] The term "about" in the context of numerical values means
that specific values may be modified by +/-10%. As regards
endpoints of ranges, the modifier "about" preferably means that the
lower endpoint may be reduced by 10% and the upper endpoint may be
increased by 10%. It is also contemplated that each numerical value
or range disclosed in this application can be absolute, i.e. that
the modifier "about" can be deleted.
[0037] If a layer (L1) is "on an upstream side" (or "on top") of a
layer (L2), this means that the layer (L1) is situated, relative to
the layer (L2), closer to the inventive media's surface which is in
contact with the unfiltered water-fuel emulsions. On the other
hand, if a layer (L1) is "on a downstream side" of a layer (L2),
this means that the layer (L1) is situated, relative to the layer
(L2), farther from the inventive media's surface which is in
contact with the unfiltered water-fuel emulsions. In the latter
case, the layer (L1) is, relative to layer (L2), closer to the
inventive media's surface which is in contact with the filtered
water-fuel emulsions, i.e. to the surface of the inventive media
from which the filtered and dried fuel exits the inventive
media.
[0038] The term "fuel" preferably refers to low sulphur diesel.
[0039] The "dust holding capacity" refers to the added weight of
trapped particles when the media reaches a target pressure drop or
terminal differential pressure such as 85 KPa.
[0040] The "water removal efficiency" in the context of the
invention is the propensity of the inventive media to remove water
from water-fuel emulsions, thereby producing dried fuel, as opposed
to allowing the water-fuel emulsion to pass through the inventive
media. Specifically, the "initial water removal efficiency" is the
water removal efficiency directly after its preparation and not
when being in usage, i.e. the filter is not loaded with particles
or heavily soaked with water. In contrast, the "average water
removal efficiency" means the mean water removal efficiency over
time when being in usage.
[0041] The "net change in water removal efficiency" is defined as
the water removal efficiency measured according to SAEJ1488 after
165 min from which the water removal efficiency measured according
to SAEJ1488 after 15 min is subtracted.
BRIEF DESCRIPTION OF THE FIGURES
[0042] FIG. 1: Construction of comparative and inventive filter
media.
[0043] FIG. 2: Overall water removal efficiency of an inventive
medium as compared to comparative medium.
THE FUEL WATER SEPARATION MEDIUM
[0044] The fuel water separation medium according to the invention
comprises, or consists (essentially) of, (A) at least one first
layer comprising nanofibers and (B) at least one second layer
comprising a fibrous web. Optionally, (C) at least one fine fiber
layer as third layer and/or (D) at least one adhesive layer may be
present. These specific layers are described in the following in
more detail:
(A) First Layer (Also Referred to as "Nanofiber Layer")
[0045] The first layer comprises, or consists (essentially) of,
nanofibers, i.e. the first layer is a nanofiber layer. It is
believed that this layer (possibly along with the second layer as
defined below) provides efficient stripping of emulsified water
and/or (surface) coalescence from water fuel emulsions.
Specifically, emulsified water assembles/coalesces into larger
droplets that may be efficiently stopped by the first layer,
thereby reducing water saturation of the second layer which would
deteriorate the second layer's water removal efficiency. Therefore,
the first layer may be considered to be a water stripping and/or
(surface) coalescing layer.
[0046] The nanofibers of the first layer have an average fiber
diameter of about 50 to about 350 nm, preferably about 100 to about
300 nm.
[0047] In preferred embodiments, the nanofibers of the first layer
may be electrospun directly onto the adjacent layer (like the
second layer or, if present, an adhesive (coating) layer as defined
below). Methods for preparing the nanofibers via electrospinning
are known in the art. The obtained electrospun nanofibers are
typically continuous or substantially continuous fibers.
[0048] In other preferred embodiments, the nanofibers may be
synthetic nanofibers prepared from the following thermoplastic
polymeric materials: polyethersulfone (PES); polyacrylonitrile;
polyamide (PA) such as nylon; fluoropolymers such as
polyvinylfluoride (PVDF); and/or mixtures thereof. In more
preferred embodiments, the nanofibers may be polyamide fibers or
fluoropolymeric fibers. In most preferred embodiments, the
nanofibers may be nylon fibers or polyvinylfluoride fibers.
[0049] In other preferred embodiments, the first layer may consist,
or consist essentially, of nanofibers as defined above.
[0050] In some embodiments, the nanofibers may be prepared from an
adhesive and polyethersulfone. Preferably, the adhesive is a
diisocyanate. The adhesive is used in an amount of about 1 to about
5% by weight and the PES is used in an amount of about 95 to about
99% by weight, based on the total weight of the corresponding
composition. This composition is mixed and manufactured into
nanofibers via electrospinning directly onto the second layer or,
if present, on an adhesive (coating) layer on top of the second
layer as defined below.
(B) Second Layer (Also Referred to as "Substrate Layer")
[0051] The second layer comprises, or consists (essentially) of, at
least one fibrous web. This fibrous web may be considered to be a
substrate layer. The fibrous web comprises, or consists
(essentially) of, cellulose fibers (also referred to as cellulosic
fibers). If the substrate layer is saturated with a binder resin
including a water repellant additive like silicone or fluorocarbon,
it is believed that the emulsified water from the water fuel
emulsions does not easily wet the inventive media's surface and
beads up on both the nanofiber layer's and the substrate layer's
surfaces. The beads coalesce into larger drops which then fall into
the collection bowl of the fuel water separator comprising the
inventive media. Therefore, the substrate layer may be also
considered to be a stripper media (and/or surface coalescer).
[0052] In preferred embodiments, the cellulosic fibers may include
about 0-100% by weight of softwood fibers and/or about 100-0% by
weight of hardwood fibers based on the total weight of the second
layer. More preferably, 40-10% by weight of softwood fibers and
60-90% by weight of hardwood fibers based on the total weight of
the second layer may be present. Exemplary softwood fibers include
fibers obtained from mercerized southern pine such as mercerized
southern pine fibers or "HPZ fibers" or southern bleached softwood
kraft such as Brunswick pine. Exemplary hardwood fibers include
fibers obtained from Eucalyptus.
[0053] In preferred embodiments, the fibrous web may comprise
cellulosic fibers in an amount of at least about 50% by weight,
preferably at least about 60% by weight or at least about 70% by
weight, more preferably at least about 80% by weight or 90% by
weight based on the total weight of second layer. In most preferred
embodiments, the fibrous web may consist (essentially) of
cellulosic fibers. Due to the presence of cellulosic fibers, it is
believed that the second layer may provide the stiffness that e.g.
synthetic (such as meltblown) base sheets of the prior art will not
be able to provide. However, if the substrate layer is not stiff
enough, it may be very difficult to make a pleated and/or
corrugated filter.
[0054] Preferably, the second layer may have a Gurley stiffness of
about 2-15 g, preferably about 3-8 g such as about 5.5 g. The
Gurley stiffness indicates the bending resistance of the analyzed
filter medium.
[0055] In preferred embodiments, the fibrous web may comprise
substantially no glass fibers. In other embodiments, the second
layer may comprise about 70 to about 100% by weight cellulosic
fibers and about 0 to about 30% by weight glass fibers, based on
the total weight of the second layer.
[0056] In other preferred embodiments, the fibrous web may comprise
substantially no synthetic fibers. In other embodiments, the second
layer may comprise about 50 to about 90% by weight cellulosic
fibers and about 50 to about 10% by weight synthetic fibers, based
on the total weight of the second layer.
[0057] The average fiber diameter of the cellulose fibers in the
second layer may be, for example, greater than or equal to about
0.5 microns, about 1 micron, about 5 microns, about 10 microns,
about 20 microns, about 50 microns, or about 75 microns. In some
instances, the average fiber diameter of the cellulose fibers may
be less than or equal to about 75 microns, about 50 microns, about
20 microns, about 10 microns, about 5 microns, about 1 micron, or
about 0.5 microns. Combinations of the above-referenced ranges are
also possible (e.g., greater than or equal to about 1 micron and
less than or equal to about 5 microns). Preferably, the average
fiber diameter is greater than or equal to about 0.5 mm and less
than or equal to about 20 microns).
[0058] In some embodiments, the cellulose fibers may have an
average length of greater than or equal to about 0.5 mm, about 1
mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 10 mm, or
about 20 mm. In some instances, the average length may be less than
or equal to about 20 mm, about 10 mm, about 5 mm, about 4 mm, about
3 mm, about 2 mm, about mm, or about 0.5 mm. Combinations of the
above-referenced ranges are also possible (e.g., greater than or
equal to about 1 mm and less than or equal to about 0.5 mm).
Preferably, the average length may be greater than or equal to
about 1 mm and less than or equal to about 7 mm.
[0059] In some embodiments, (micro-)fibrillated fibers (like
(micro-)fibrillated cellulosic fibers) may be present in the second
layer such as up to about 30% by weight of (micro-) fibrillated
fibers, preferably up to 20% by weight of (micro-)fibrillated
fibers, more preferably up to 10% by weight of (micro-)fibrillated
fibers. In alternative and more preferred embodiments,
substantially no (micro-) fibrillated cellulose fibers may be
present in the second layer.
[0060] In preferred embodiments, the second layer may have a basis
weight in the range of 60-250 g/m.sup.2, preferably in the range of
100-170 g/m.sup.2.
[0061] In some embodiments, the air permeability of the second
layer (w/phenolic resin) may be greater than or equal to about 10
cfm and/or less than or equal to about 20 cfm. Preferably, the air
permeability may be greater than or equal to about 12 cfm and less
than or equal to about 18 cfm such as e.g. 13 cfm, 16 cfm, or 17
cfm.
[0062] In other preferred embodiments, the second layer may
comprise at least one binder resin such as a phenolic resin, an
acrylic resin, a melamine resin, a silicone resin, a fluorocarbon
resin/fluoropolymer, an epoxy resin and/or mixtures thereof.
Preferably, the second layer may be coated or impregnated/saturated
with the binder resin. In preferred embodiments, the binder resin
may have a concentration of from 10-30 by weight, preferably 15-20%
by weight, of the second layer.
[0063] The second layer may optionally include at least one
additive which is common in the art. The at least one additive may
be selected from a wet strength additive, a water repellant, a
flame-retardant agent, a coloring agent, a hydrophobic agent, a
hydrophilic agent, a wetting agent, an antimicrobial agent or an
antistatic agent.
[0064] In preferred embodiments, the second layer may not comprise
a water repellant additive without sacrificing the obtained water
removal efficiency.
[0065] In some preferred embodiments, the second layer may be
present on a downstream side of the first layer.
[0066] In some alternative preferred embodiments, the second layer
may be present on an upstream side of the first layer.
(C) Optional at Least One Third Layer (Also Referred to as "Fine
Fiber Layer")
[0067] The at least one third layer is a fine fiber layer and may
be optionally present in the inventive media. This at least one
fine fiber layer serves to protect the downstream layers of the
inventive media by capturing particulate impurities from the
water-fuel emulsions to be filtered, thereby avoiding the clogging
of the second layer's pores which would deteriorate the second
layer's absorption performance and ultimately its water removal
efficiency. Therefore, the fine fiber layer may be considered to be
a protective layer.
[0068] In one embodiment, the inventive medium may not include a
protective fine fiber layer as third layer on an upstream side of
the first layer.
[0069] In an alternative embodiment, the inventive medium may
comprise at least one fine fiber layer as protective layer, wherein
the at least one fine fiber layer may be present on an upstream
side of the first layer. In one embodiment, two fine fiber layers
may be present, wherein one of the fine fiber layers may be present
on an upstream side of the first layer and the other fine fiber
layer may be present on a downstream side of the first layer.
[0070] In preferred embodiments, the at least one third layer has a
basis weight of about 10 to about 100 g/m.sup.2 such as about 15 to
about 80 g/m.sup.2.
[0071] In preferred embodiments, the fine fiber layer may comprise,
or may consist (essentially) of, synthetic fibers. Synthetic fibers
may include any suitable type of synthetic polymer fibers. Examples
of suitable (thermoplastic) synthetic polymers fibers include, but
are not limited to, fibers prepared from polyester; polyethylene
terephthalate; polyolefin such as polyethylene or polypropylene;
polybutylene terephthalate; polyimide; and/or mixtures thereof.
[0072] Synthetic fibers may also include multi-component fibers,
i.e. fibers having multiple compositions such as bicomponent
fibers.
[0073] In some embodiments, the synthetic fibers of the fine fiber
layer may be formed via meltblowing, meltspinning, or spunbonding.
These methods are known in the art. The obtained synthetic fibers
are typically continuous and/or substantially continuous
fibers.
[0074] In preferred embodiments, the third layer may comprise, or
may consist (essentially) of, two sub-layers: (i) a spunbond fine
fiber layer, such as a PET layer having preferably a basis weight
of about 8 to about 30 g/m.sup.2; and (ii) a meltblown fine fiber
layer, such as a PET layer having preferably a basis weight of
about 25 to about 80 g/m.sup.2. Preferably, the spunbond fine fiber
layer may be on an upstream side of the meltblown fine fiber layer
and both sub-layers may be on an upstream side of the first and
second layer. In some preferred embodiments, the meltblown layer
may be present on a downstream side of the spunbond layer.
[0075] In other preferred embodiments, the third layer may
comprise, or may consist (essentially) of, one sub-layer: a
spunbond fine fiber layer, such as a PP/PE layer having preferably
a basis weight of about 10 to about 20 g/m.sup.2 such as 17
g/m.sup.2. Preferably, this spunbond fine fiber sub-layer may be on
a downstream side of the first and second layer.
[0076] The diameter range of the synthetic fibers of this meltblown
fine fiber layer in the inventive media may be between about 0.1 to
about 30 microns, more preferably between about 0.1 to about 5
microns for a majority of fibers such as e.g. 95% or 98% of the
total number of meltblown fibers.
[0077] The average diameter of the synthetic fibers of this
spunbond layer in the inventive media may be, for example, greater
than or equal to about 10 microns, about 20 microns, or about 30
microns. In some instances, these synthetic fibers may have an
average diameter of less than or equal to about 30 microns, about
20 microns, about 10 microns. Preferred is an average fiber
diameter of less than or equal to about 20 microns and greater than
or equal to 0.5 or micron(s).
(D) Optional Adhesive Layer(s)
[0078] In preferred embodiments, the inventive medium may comprise
at least one adhesive layer or adhesive coating between adjacent
first, second or, if present, third layers as defined above.
Specifically, in one preferred embodiment, the inventive medium may
comprise at least one adhesive layer between the first and the
second layer and/or between the first and the third layer, if
present. In another preferred embodiment, the inventive medium may
comprise at least one adhesive layer between the first and the
second layer and/or between the second and the third layer, if
present.
[0079] The adhesive can be any adhesive that can be spray-coated
onto the layer to he coated. Preferably, the adhesive is selected
from a polyurethane; acrylate; PVA; polyolefin ethylene co-polymer;
and/or rubber-based adhesive. Most preferred are polyamide hot melt
adhesives, polyurethane hot melt adhesives or PVOH stabilized
carboxylated vinyl acetate-ethylene copolymers. In preferred
embodiments, the adhesive is applied to the layer to be coated in a
manner such that it does not affect the permeability of the
corresponding layer. That is, the adhesive is applied with a coat
weight of less than about 5 gsm.
[0080] Alternatively, the inventive medium may comprise no adhesive
layer between the first and the second layer and/or between the
first and the third layer, if present, but these layers are
laminated or adhered to by any commonly known technique(s).
Specific Embodiments of the Fuel Water Separation Medium
[0081] In one embodiment, the inventive medium may comprise the
second layer on a downstream side of the first layer.
[0082] In preferred embodiments, the inventive medium may not
include the protective fine fiber layer as third layer on an
upstream side of the first layer.
[0083] In an alternative embodiment, the inventive medium may
comprise the second layer on an upstream side of the first
layer.
[0084] In some other preferred embodiments, the inventive medium
may comprise the third fine fiber layer on an upstream side of the
first layer.
[0085] In other preferred embodiments, the inventive medium may
comprise, or consist (essentially) of, the second layer on a
downstream side of the first layer and the third (fine fiber) layer
is on an upstream side of the first layer.
[0086] In other preferred embodiments, the inventive medium may
comprise, or consist (essentially) of, a first fine fiber layer on
an upstream side of the second layer, the second layer on an
upstream side of the first layer and a second fine fiber layer on a
downstream side of the first layer.
[0087] In most preferred embodiments, the inventive medium may
therefore comprise, or consist (essentially) of, the following
layers from downstream to upstream: (B) the second layer; (D1) a
first adhesive layer on top of the second layer; (A) the first
layer on top of the first adhesive layer; (D2) a second adhesive
layer on top of the first layer; and (C) a fine fiber layer on top
of the second adhesive layer. Preferably, the fine fiber layer may
comprise, or consist (essentially) of, two sub-layers, namely a
meltblown (such as PET) and a spunbond (such as PET) fine fiber
layer.
[0088] In other preferred embodiments, the inventive medium may
therefore comprise, or consist (essentially) of, the following
layers from downstream to upstream: (B) the second layer; (A) the
first layer on top of the second layer; and (C) a first fine fiber
layer on top of the first layer.
[0089] In other preferred embodiments, the inventive medium may
therefore comprise, or consist (essentially) of, the following
layers from downstream to upstream: (B) the second layer; (D) an
adhesive layer on top of the second layer; and (A) the first
nanofiber layer on top of the adhesive layer.
[0090] In most preferred embodiments, the inventive medium may
therefore comprise, or consist (essentially) of, the following
layers from downstream to upstream: (C1) a first fine fiber layer;
(A) the first layer on top of the first fine fiber layer; (D1) a
first adhesive layer on top of the first layer; (B) the second
layer; (D2) a second adhesive layer on top of the second layer; and
(C2) a second fine fiber layer on top of the second layer.
Preferably, the first fine fiber layer may comprise, or consist
(essentially) of, two sub-layers, namely a meltblown (such as PET)
and a spunbond (such as PET) fine fiber layer, and the second fine
fiber layer may comprise, or consist (essentially) of, a spunbond
fine fiber layer such as bicomponent PE/PP.
[0091] In other preferred embodiments, the inventive medium may
therefore comprise, or consist (essentially) of, the following
layers from downstream to upstream: (C1) a first fine fiber layer;
(A) the first layer on top of the first fine fiber layer; (B) the
second layer; and (C2) a second fine fiber layer on top of the
second layer.
[0092] The inventive medium has a basis weight of about 100-300
g/m.sup.2, preferably about 150-300 g/m.sup.2.
[0093] The inventive medium is characterized by having a net change
in water removal efficiency being preferably less than about 10%,
more preferably less than about 5%. Specifically, the net change in
water removal efficiency is defined as follows:
net change in water removal efficiency=(water removal efficiency
after 165 min)-(water removal efficiency after 15 min);
wherein the water removal efficiency is measured according to
SAEJ1488.
[0094] It has been found that the inventive medium may have
excellent mechanical properties. In particular, the inventive
medium may preferably show at least one of the following
properties: [0095] a basis weight of about 150-300 g/m.sup.2 when
tested according to TAPPI Standard T 410 om-02; and/or [0096] an
overall fuel-water separation efficiency of at least about 55%
after 15 minutes when tested according to SAEJ1488; and/or [0097]
an overall fuel-water separation efficiency of at least about 60%
after 165 minutes when tested according to SAEJ1488; and/or [0098]
a TSI aerosol penetration of less than or equal to about 15%;
and/or [0099] a TSI resistance to flow of about 5-75 mm H.sub.2O;
and/or [0100] an air permeability of about 3-20 cfm when tested
according to TAPPI Standard T 251 cm-85; and/or [0101] a mean flow
pore size of about 2-10 um when tested according to ASTM 316-03
(2011); and/or [0102] a leakage-corrected Frazier of 3-20 cfm when
tested according to TAPPI Standard T 251 cm-85.
[0103] Further, it was found that the inventive media is also
suitable for use as a particle removal filter medium for removing
particles from fuel or oil.
Process for the Preparation of the Filter Medium
[0104] The process for the preparation of the inventive medium
comprises the steps of [0105] providing a first homogeneous slurry;
[0106] supplying the first slurry onto a dewatering screen to form
a first deposit; [0107] removing the water from the deposit to form
a wet fibrous web; [0108] drying the wet fibrous web while heating
to form the second layer; [0109] optionally saturating the thus
obtained second layer with a binder resin; [0110] optionally
coating of a first adhesive layer on top of the thus obtained
second layer; [0111] applying the first layer on top of the second
layer or on top of the first adhesive layer coated onto the second
layer, wherein the applying is preferably performed using
electrospinning; [0112] O optionally coating of a second adhesive
layer (i) on top of the first layer or (ii) on top of the second
layer; and [0113] optionally applying the third layer (iii) on top
of the first layer, (iv) on top of the second adhesive layer coated
onto the first layer, if present, (v) on top of the second layer or
(vi) on top of the second adhesive layer coated onto the second
layer, if present, wherein the applying is preferably performed by
meltblowing a first fine fiber (sub-)layer and spunbonding a second
fine fiber layer on top of the first fine fiber (sub-) layer;
wherein the first slurry comprises water and cellulosic fibers.
[0114] In this process, a first homogenous slurry is provided which
may be prepared according to methods known in the art such as by
adding and mixing the cellulosic fibers in water.
[0115] Once the first homogeneous slurry is prepared, it is applied
onto a dewatering screen in order to prepare the second layer. This
screen can be any screen commonly used in a paper making process.
Preferably, this screen is a dewatering endless screen. Upon
supplying the first slurry onto the dewatering screen, a first
deposit is formed on the screen. During or after deposition of the
slurry, water is removed to form a wet fibrous mat or sheet.
Subsequently, the wet fibrous mat or sheet is dried while
heating.
[0116] Optionally, impregnation of the thus obtained layer with a
binder resin may be carried out followed by drying, and/or a first
adhesive layer may be (spray-)coated on top of the thus prepared
dried fibrous mat or sheet which corresponds to the second layer as
defined above. The binder resin and the adhesive can be any one as
defined above.
[0117] Next, nanofibers are applied on top of the second layer or
on top of the first adhesive layer, if present, wherein the
application is preferably performed using electrospinning. Methods
for electrospinning of the nanofibers are known in the art.
[0118] Optionally, a second adhesive layer may be (spray-)coated
(i) on top of the thus prepared nanofiber layer or (ii) on top of
the second layer. In the latter case, the nanofiber layer is
present on the side opposite to the second adhesive layer, i.e. the
second layer has a nanofiber layer on a downstream side and the
second adhesive layer on an upstream side of the second layer.
[0119] Optionally, a fine fiber layer may be applied (iii) on top
of the first layer, (iv) on top of the second adhesive layer coated
onto the first layer, if present, (v) on top of the second layer or
(vi) on top of the second adhesive layer coated onto the second
layer, if present. The application is preferably performed by
meltblowing a first fine fiber (sub-) layer and spunbonding a
second fine fiber layer on top of the first fine fiber (sub-)layer
as defined above.
Examples
[0120] The invention will now be described in further detail by way
of the following examples:
Test methods:
[0121] Basis Weight: The basis weight is measured according to
TAPPI Standard T 410 om-02 and reported in grams per square meter
(gsm or g/m.sup.2).
[0122] Caliper or Thickness: The caliper or thickness of the media
is determined according to TAPPI Standard T 411 om-05 using a
Thwing Albert 89-100 Thickness Tester.
[0123] Corrugation Depth: The corrugation depth is the difference
between the caliper of the flat sheet of media and the thickness of
the sheet after corrugating the media.
[0124] Air Permeability (Frazier): The air permeability is
determined according to TAPPI Standard T 251 cm-85. Specifically,
the air permeability of the filter medium as defined by airflow was
measured in cubic feet per minute per square foot (cfm/sf or also
referred to as cfm or CFM) at a pressure drop of 125 Pascal (0.5''
water column) using a Textest FX 3300 Air Permeability Tester, a
calibration plate as supplied by Textest, Ltd., Zurich, Switzerland
and a thin plastic film--GEC Heatseal letter-size laminating pouch
or equivalent plastic film under controlled atmospheric conditions.
The units "cfm" and "cfm/sf" are interchangeable. Air permeability
may also be referred to porosity, Frazier or Textest.
[0125] The Standard Textest procedure is as follows:
Saturated/Dried paper is to be cured for 5 minutes at 175.degree.
C. (Solvent Based Systems) or 2 minutes at 175.degree. C. Water
Based Systems) prior to testing. Saturated/Cured paper may be given
an abbreviated cycle at an elevated temperature, since it is only
necessary to drive off any moisture present. Unsaturated (Raw)
paper samples may be tested Off Machine; drying is not necessary.
Test Pressure: 125 Pa (or 0.5'' w.c.). Place a sample to be
measured felt side up between the clamping arm and the test head.
Push the clamping arm down until it clicks, and locks into place,
starting the test. Then note and record the displayed reading.
Release the clamping arm by pressing down until it clicks a second
time, stopping the test. All subsequent readings should be taken in
the same fashion.
[0126] The Textest clamp leakage test procedure is as follows:
Textest leakage is determined by using a thin plastic film sheet
over the grooved media under the clamping mechanism on the textest
machine. Test the sample according to the above standard textest
test procedure and then note and record the small leakage
measurement.
[0127] Mean Flow Pore Size (MFP): The size of the pores in the
medium was determined using a bubble point method according to ASTM
316-03 (2011) utilizing a Porometer G3 Series (Quantachrome
Instruments) and is reported in microns (.mu.m or um).
[0128] Gurley stiffness: The stiffness of the medium was determined
according to TAPPI 543om-05 using a Gurley-type tester. The Gurley
stiffness analyzes the ability of a sample to resist an applied
bending force (i.e. the sample's bending resistance).The unit of
the Gurley stiffness is gf (gram force) which is herein sometimes
also referred to as gms or g.
[0129] TSI penetration: The TSI penetration was determined using a
TSI Incorporated Automated Filter Tester (Model 8130) to generate a
salt (NaCl) or oil (DEHS) aerosol with particles of 0.3 micron
diameter (modified EN 143 procedure). The particles in the upstream
aerosol are counted and then the aerosol is used to challenge a
flat sheet test sample (100 cm.sup.2) at a flow rate of 32 L/min.
The particles in the aerosol are then counted again after passing
completely through the test sample. The ratio between the
quantities of particles counted before (upstream) and after
(downstream) filtering is reported as the percent penetration, i.e.
the downstream count is divided by the upstream count and
multiplied by 100.
[0130] TSI Resistance to Flow (mm H.sub.2O): TSI Resistance to flow
is a measure of the pressure drop across the filter media. The
higher the TSI resistance to flow, the greater the pressuredrop
across the media. TSI Resistance is measured via an electronic
pressure transducer and reported alongside the penetration number
and the test flow rate. The measurement range of the instrument is
0-150mm H.sub.2O (0-1470 Pa) with an accuracy of 2 of the scale
(TSI tester system: Model 8127 8130 Automated filter Tester).
[0131] Fuel Filter Water Separation Efficiency: The filter medium
was analyzed according to the SAEJ1488 test standard using a
diesel-water emulsion (ultra-low sulfur diesel containing 2500 ppm
water). Water removal is tested by taking samples upstream and
downstream of the filter medium. The amount of water in the
upstream and downstream samples is tested via Karl Fischer
titration according to known methods.
Example 1 (Comparative)
[0132] The base substrate is a 100% cellulosic wet laid nonwoven
comprising 28.5% NESK and 71.4% Eucalyptus pulp having a basis
weight of 128 gsm and a flat sheet caliper of 0.36 mm (4 mils). The
substrate is saturated with 17% phenolic resin. The substrate
(w/phenolic resin) has an air permeability of 16 cfm. This sample
does not include a water repellant additive.
Example 2
[0133] The base substrate is the same as in Example 1, but has an
additional layer of polyether sulfone nanofibers electrospun
directly onto the substrate at an add-on of 2 gsm for a total basis
weight of 130 gsm and caliper of 0.38 mm (15 mils) (instructions
for manufacturer; only theoretical values). The nanofibers have an
average fiber diameter of 100-300 nm.
Example 3 (Comparative)
[0134] The base substrate has a total basis weight of 114 gsm and
is a wet-laid nonwoven consisting of 100% cellulosic fibers (81.6%
by weight cellulosic fibers in the medium). The substrate is
saturated with 18% by weight phenolic resin including 1-3% by
weight silicone as H.sub.2O repellant additive and 0.4% by weight
wet strength additive. The substrate (w/phenolic resin) has an air
permeability of 13 cfm/sf. The base substrate has an additional
adhesive layer (hot melt additive) on an upstream side and an
additional protective fine fiber layer of meltblown PET (55 gsm)
and spunbond PET (15 gsm) on an upstream side directly onto the
adhesive layer at an add-on of 70 gsm. The resulting filter medium
is then corrugated.
Example 4
[0135] The base substrate has a total basis weight of 144 gsm and
is a wet-laid nonwoven consisting of 100% cellulosic fibers (81.6%
by weight cellulosic fibers in the medium). The substrate is
saturated with 18% by weight phenolic resin including 1-3% by
weight silicone as H.sub.2O repellant additive and 0.4% by weight
wet strength additive. The substrate (w/phenolic resin) has an air
permeability of 13 cfm. The base substrate has an adhesive layer
(PVOH stabilized, carboxylated vinyl acetate-ethylene copolymer))
on an upstream side and a layer of nylon nanofibers electrospun
directly onto the adhesive layer on an upstream side. An additional
adhesive layer (hot melt additive) on an upstream side directly
onto the nanofiber layer is present. The nylon nanofibers' diameter
is 90-340 nm. An additional protective fine fiber layer of
meltblown PET (55 gsm) and spunbond PET (15 gsm) on an upstream
side directly onto the additional adhesive layer at an add-on of 70
gsm is present. The resulting filter medium is then corrugated.
[0136] Table I shows the structures of examples 3 and 4 (see also
FIG. 1):
TABLE-US-00001 TABLE I Example 3 Example 4 (base paper A--fine
fiber) (base paper A--nylon nano--fine fiber) 5 Base paper Base
paper Weight: 114 gsm Weight: 114 gsm 18% Phenolic Resin with 18%
Phenolic Resin with silicone silicone additive, additive, 0.4%
Wet-strength additive, 0.4% Wet strength additive, 81.6% Cellulose
Fibers 81.6% Cellulose Fibers Corrugated Corrugated 4 N/A Adhesive
layer 3 N/A Nanofiber Layer (Nylon) 2 Adhesive layer 1 70 gsm
Fine-fiber Layer 55 gsm layer of PBT meltblown 15 gsm PET
spunbond
Example 5 (Comparative)
[0137] The base substrate has a total basis weight of 150 gsm and
is a wet-laid nonwoven consisting of 100% cellulosic fibers (84% by
weight cellulosic fibers in the medium). The substrate is saturated
with 16% by weight phenolic resin including 1-3% by weight
fluorocarbon as H.sub.2O repellant additive and 0.6% by weight wet
strength additive. The substrate (w/phenolic resin) has an air
permeability of 16.8 cfm. The base substrate has an additional
protective fine fiber layer of meltblown PET (55 gsm) and spunbond
PET (15 gsm) on an upstream side directly onto the substrate layer
at an add-on of 70 gsm. The resulting filter medium is then
corrugated.
Example 6
[0138] The base substrate has a total basis weight of 150 gsm and
is a wet-laid nonwoven consisting of 100% cellulosic fibers (84% by
weight cellulosic fibers in the medium). The substrate is saturated
with 16% by weight phenolic resin including 1-3% by weight
fluorocarbon as H.sub.2O repellant additive and 0.6% by weight wet
strength additive. The substrate (w/phenolic resin) has an air
permeability of 17 cfm. The base substrate has an additional
adhesive layer (polyurethane, heat activated water dispersion) on
an upstream side. In addition, a layer of polyamide nanofibers
electrospun directly onto the adhesive layer on an upstream side
and an additional adhesive layer (polyurethane, hot melt adhesive)
on an upstream side directly onto the nanofiber layer are present.
The polyamide nanofibers' average diameter is about 130-200 nm. An
additional protective fine fiber layer of meltblown PET (55 gsm)
and spunbond PET (15 gsm) on an upstream side directly onto the
adhesive layer at an add-on of 70 gsm is further present. The
resulting filter medium is corrugated.
Example 7
[0139] The base substrate has a total basis weight of 150 gsm and
is a wet-laid nonwoven consisting of 100% cellulosic fibers (84.0%
by weight cellulosic fibers in the medium). The substrate is
saturated with 16.0% by weight phenolic resin including 1-3% by
weight fluorocarbon as H.sub.2O repellant additive and 0.6% by
weight wet strength additive. The substrate (w/phenolic resin) has
an air permeability of 17 cfm. The base substrate has an additional
adhesive layer (polyurethane, heat activated water dispersion) on
an upstream side. In addition, a layer of polyvinylidenefluoride
(PVDF) nanofibers electrospun directly onto the adhesive layer on
an upstream side and an additional adhesive layer (polyurethane,
hot melt additive) on an upstream side directly onto the nanofiber
layer are present. The polyamide nanofibers' average diameter is
about 130-200 nm. An additional protective fine fiber layer of
meltblown PET (55 gsm) and spunbond PBT (15 gsm) on an upstream
side directly onto the adhesive layer at an add-on of 70 gsm is
further present. The resulting filter medium is corrugated.
Example 8 (Comparative)
[0140] The base substrate has a total basis weight of 150 gsm and
is a wet-laid nonwoven consisting of 100% cellulosic fibers (84% by
weight cellulosic fibers in the medium). The substrate is saturated
with 16% by weight phenolic resin including 1-3% by weight
fluorocarbon as H.sub.2O repellant additive and 0.6% by weight wet
strength additive. The substrate (w/phenolic resin) has an air
permeability of 16.8 cfm. The resulting filter medium is then
corrugated.
Example 9
[0141] The base substrate has a total basis weight of 150 gsm and
is a wet-laid nonwoven consisting of 100% cellulosic fibers (84% by
weight cellulosic fibers in the medium). The substrate is saturated
with 16% by weight phenolic resin including 1-3% by weight
fluorocarbon as H.sub.2O repellant additive and 0.6% by weight wet
strength additive. The substrate (w/phenolic resin) has an air
permeability of 17 cfm. The base substrate has an additional
adhesive layer (polyurethane, heat activated water dispersion) on
an upstream side. In addition, a layer of polyamide nanofibers
electrospun directly onto the adhesive layer on an upstream side is
present. The polyamide nanofibers' average diameter is about
130-200 nm. The resulting filter medium is corrugated.
Example 10
[0142] The base substrate has a total basis weight of 150 gsm and
is a wet-laid nonwoven consisting of 100% cellulosic fibers (84.0%
by weight cellulosic fibers in the medium). The substrate is
saturated with 16.0% by weight phenolic resin including 1-3% by
weight fluorocarbon as H.sub.2O repellant additive and 0.6% by
weight wet strength additive. The substrate (w/phenolic resin) has
an air permeability of 17 cfm. The base substrate has an additional
adhesive layer (polyurethane (PU), heat activated water dispersion)
on an upstream side. In addition, a layer of polyvinylidenefluoride
(PVDF) nanofibers electrospun directly onto the adhesive layer on
an upstream side is present. The polyamide nanofibers' average
diameter is about 130-200 nm. The resulting filter medium is
corrugated.
[0143] Table II-III show the furnish compositions of Examples 1-10
and Tables IV-VI show the properties of the thus obtained filter
media:
TABLE-US-00002 TABLE II Furnish compositions of Examples 1-4. Ex. 1
Ex. 2 Ex. 3 Ex. 4 LAYER TYPE (comp.) (inv.) (comp.) (inv.)
PROTECTIVE -- -- 15 gsm PET 15 gsm PET LAYER -- -- 55 gsm PBT 55
gsm PBT ADHESIVE -- HM-0652 HM-0652 NANOLAYER Fiber type -- PES --
Nylon Average fiber diameter -- 100-300 nm -- 0.09-0.34 um ADHESIVE
-- -- -- PVOH stabilized. carboxylated vinyl acetate-ethylene
copolymer SUBSTRATE % Fibers in substrate 83% 83% 81.6% 81.6% LAYER
layer: Hardwood (Eucalyptus) 71.4% 71.4% 82.9% 82.9% Softwood
(pine) 28.5% 28.5% 17.1% 17.1% Substrate BW (gsm) 121 121 114 114
Resin (phenolic) 17% 17% 18.0% 18.0% Water repellant additive -- --
Silicone Silicone Wet strength additive 0.20% 0.20% 0.4% 0.4%
FILTER MEDIUM Basis weight (gsm) 121 121 184 ~185
TABLE-US-00003 TABLE III Furnish compositions of Examples 5-10. Ex.
5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 LAYER TYPE (comp.) (inv.) (inv.)
(comp.) (inv.) (inv.) PROTECTIVE 15 gsm PET 15 gsm PET 15 gsm PET
-- -- -- LAYER 55 gsm PBT 55 gsm PBT 55 gsm PBT -- -- -- ADHESIVE
-- PU PU -- -- -- NANOLAYER Fiber type -- Polyamide PVDF --
Polyamide PVDF Average fiber -- 130-200 nm 130-200 nm -- 130-200
130-200 diameter nm nm ADHESIVE -- PU PU -- PU PU SUBSTRATE %
Fibers in Medium 84.0% 84.0% 84.0% 84.0% 84.0% 84.0% LAYER Hardwood
(Eucalyptus) 63.0% 63.0% 63.0% 63.0% 63.0% 63.0% Softwood (pine)
37.0% 37.0% 37.0% 37.0% 37.0% 37.0% Substrate BW (gsm) 150 150 150
150 150 150 Resin (phenolic) 16.0% 16.0% 16.0% 16.0% 16.0% 16.0%
Water repellant Fluoro- Fluoro- Fluoro- Fluoro- Fluoro- Fluoro-
additive carbon carbon carbon carbon carbon carbon Wet strength
add. 0.6% 0.6% 0.6% 0.6% 0.6% 0.6% FILTER Basis weight (gsm) 150
222 222 150 152 152 MEDIUM
TABLE-US-00004 TABLE IV Properties of Examples 1-4. Ex. 1 Ex. 2 Ex.
3 Ex. 4 (comp.) (inv.) (comp.) (inv.) Frazier (cfm) 15.2 17.3 8.7
10.0 Leakage (cfm) 1.1 1.0 0.8 0.8 Leakage-corrected Frazier (cfm)
14.1 16.3 7.9 9.2 Flow(Liters per minute) 32 32 32 32 Resistance to
Flow mm H.sub.2O) 10.1 9.9 20.4 16.0 TSI Aerosol Penetration (%)
69.20 50.70 33.80 11.10 Caliper (mils) 23.60 23.70 30 35.7 Mean
Flow Pore Size 20.20 19.40 13.5 13.5 Average Water Removal (%) 53
57 64% 79 Fuel water separation efficiency 67% 64 75% 8 after 15
min. (SAEJ1488) (%) Fuel water separation efficiency 55% 60 60% 7
after 165 min. (SAEJ1488) (%) NET Change in Water Removal 12% 3%
15% 3% Efficiency (%)
TABLE-US-00005 TABLE V Properties of Examples 5-10. Ex. 5 Ex. 6 Ex.
7 Ex. 8 Ex. 9 Ex. 10 (comp.) (inv.) (inv.) (comp.) (inv.) (inv.)
Frazier (cfm) 9.6 5.2 5.7 13.1 6.7 7.0 Leakage (cfm) 1.4 0.9 1.1
2.0 1.3 1.6 Leakage-corrected Frazier 8.2 4.3 4.7 11.1 5.4 5.4
(cfm) Flow (Liters per minute) 32 32 32 32 32 32 Resistance to Flow
(mm H2O) 20.3 30.9 30.8 14.8 38.7 33.2 TSI Aerosol Penetration (%)
13.60 0.97 0.50 72.40 0.75 1.09 Caliper (mils) 36.70 34.20 35.8
25.80 24.80 25.90 Mean Flow Pore Size 12.10 2.25 2.3 18.50 2.09
2.09 Average Water Removal (%) 52% 66% 70% 23% 91% 88% Fuel water
separation 58% 69% 71% 45% 80% 57% efficiency after 15 min.
(SAEJ1488) (%) Fuel water separation 47% 61% 69% 18% 95% 96%
efficiency after 165 min. (SAEJ1488) (%) NET change in water
removal 11% 8% 2% 27% -14% -39% efficiency (%)
TABLE-US-00006 TABLE VI Water removal efficiencies over time
(determined according to SAEJ1488; see also FIG. 2). Time Ex. 1 Ex.
2 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 (min) (comp.) (inv.) (comp.)
(inv.) (inv.) (comp.) (inv.) (inv.) 15 67% 64% 58% 69% 71% 45% 80%
57% 45 47% 52% 56% 61% 67% 19% 92% 91% 75 47% 55% 51% 70% 70% 19%
94% 96% 105 51% 57% 52% 70% 71% 21% 93% 95% 135 50% 56% 48% 67% 71%
17% 94% 95% 165 55% 60% 47% 61% 69% 18% 95% 96% NET change in 12%
3% 11% 8% 2% 27% -14% -39% water removal efficiency (%)
[0144] Tables IV-VI and FIG. 2 show that the initial and average
water removal efficiency performance of the inventive media with
nanofiber coating (Examples 2, 4, 6, 7, 9 and 10) is higher than
the one of the same control media without nanofiber coating
(Examples 1, 3, 5 and 8). Moreover, the control medium without
nanofiber coating (Examples 1, 3, 5 and 8) loses its fuel-water
efficiency over time to a much greater extent than the same
inventive medium with nanofiber coating (Examples 2, 4, 6, 7, 9 and
10). The negative NET change in water removal efficiency is
indicative for enhanced water removal efficiency over time (see
Examples 9 and 10). Thus, the water removal performance of the
inventive media remains consistent or is even increased over time
compared to the control media without nanofiber coating.
[0145] Moreover, a comparison between Examples 6 and 9 (or Examples
7 and 10) illustrates that the presence of a protective fine fiber
layer as third layer on an upstream side from the nanofiber layer
is not essential for achieving the desired initial and average
water removal efficiency and/or the desired NET change in water
removal efficiency which is indicative for the long term
performance of the fuel water separation medium or its life time
cycle. In addition, the water removal efficiency (initial, average,
NET change) obtained for the inventive media of Examples 4, 6, 7, 9
and 10 illustrates that nanofibers formed from polyamide or PVDF
are particularly preferred.
Specific Embodiments
[0146] The invention may be further illustrated by the following
specific embodiments:
1. A self-cleaning filter media for use in fuel and hydraulic oil
filtration applications comprising: a first layer on an upstream
side of the self-cleaning media, the first layer comprising
polyether sulfone nanofibers having a diameter of 50-1000 nm
(0.05-1 micron) and a basis weight of at least 1 gsm; a second
layer on a downstream side of the self-cleaning media, the second
layer comprising a wet laid nonwoven; The self-cleaning filter
media having a dust holding capacity of at least 5 mg/cm.sup.2
according to ISO 19438 multipass test for fuel filtration. 2. The
self-cleaning filter media of item 1, wherein the second layer
comprises glass microfibers. 3. The self-cleaning filter media of
item 2, wherein the second layer comprises at least 3% glass
microfibers. 4. The self-cleaning filter media of item 1, wherein
the self-cleaning filter media has a fuel filtration efficiency of
greater than 99% for 4 micron particles when a filter element is
tested according to ISO 19438. 5. The self-cleaning filter media of
item 1, wherein the self-cleaning filter media has an oil
filtration efficiency of greater than 99% for 4 micron particles
when a filter element is tested according to ISO 4548-12. 6. The
self-cleaning filter media of item 1, wherein the self-cleaning
filter media has a fuel-water separation efficiency of at least 99%
when a flat sheet is tested according to ISO 16332. 7. The
self-cleaning filter media of item 1, wherein the first layer
comprises nanofibers having a diameter of 500-700 nm. 8. The
self-cleaning filter media of item 1, wherein the nanofibers of the
first layer are electrospun directly onto the second layer. 9. The
self-cleaning filter media of item 1, wherein the nanofibers are
prepared from polyethersulfone and an adhesive. 10. The
self-cleaning filter media of item 10, wherein the nanofibers
comprise an electrospun blend of the polyether sulfone and the
adhesive. 11. The self-cleaning filter media of item 10, wherein
the adhesive is blended with the polyethersulfone in an amount of
1-5% prior to electrospinning the first layer. 12. A filter element
comprising the media of item 1. 13. The filter element of item 12,
wherein the filter element has a fuel filtration efficiency of
greater than 99% for 4 micron particles when a filter element is
tested according to ISO 19438. 14. The filter element of item 12,
wherein the filter element has an oil filtration efficiency of
greater than 99% for 4 micron particles when the filter element is
tested according to ISO 4548-12. 15. The filter element of item 12,
wherein the filter element has a lifetime of at least 1:30 hr (90
minutes) when tested according to ISO 19438 using Medium Test Dust
and a pressure drop of 70 kPa. 16. The filter element of item 12,
wherein the filter element has a lifetime of at least 1:30 hr (90
minutes) when tested according to ISO 4548-12 using Medium Test
Dust and a pressure drop of 70 kPa. 17. The filter element of item
12, wherein the filter element has a lifetime of at least 2.0 hr
(120 minutes) when tested according to ISO 19438 using Medium Test
Dust and a pressure drop of 70 kPa. 18. The filter element of item
12, wherein the filter element has a lifetime of at least 2.0 hr
(120 minutes) when tested according to ISO 4548-12 using Medium
Test Dust and a pressure drop of 70 kPa. 19. A method of filtering
particles from fuel, comprising the step of: passing the fuel
through filter element having a self-cleaning filter media that
comprises a first layer on an upstream side of the self-cleaning
media, the first layer comprising polyether sulfone nanofibers
having a diameter of 50-1000 nm (0.05-1 micron) and a basis weight
of at least 1 gsm; a second layer on a downstream side of the
self-cleaning media, the second layer comprising a wet laid
nonwoven; wherein the self-cleaning filter media has a dust holding
capacity of at least mg/cm2 according to ISO 19438 multipass test
for fuel filtration, such that the fuel passes first through the
first layer and then through the second layer so that particles
collect as a cake on a surface of the first layer and, when
sufficient particles have accumulated, the cake sloughs off and can
be collected at the bottom of the filter element. 20. A method of
filtering particles from hydraulic oil, comprising the step of:
passing the hydraulic oil through filter element having a
self-cleaning filter media that comprises a first layer on an
upstream side of the self-cleaning media, the first layer
comprising polyether sulfone nanofibers having a diameter of
50-1000 nm (0.05-1 micron) and a basis weight of at least 1 gsm; a
second layer on a downstream side of the self-cleaning media, the
second layer comprising a wet laid nonwoven; wherein the
self-cleaning filter media has a dust holding capacity of at least
5 mg/cm2 according to ISO 19438 multipass test for fuel filtration,
such that the hydraulic oil passes first through the first layer
and then through the second layer so that particles collect as a
cake on a surface of the first layer and, when sufficient particles
have accumulated, the cake sloughs off and can be collected at the
bottom of the filter element.
* * * * *