U.S. patent application number 14/096745 was filed with the patent office on 2014-06-12 for antimicrobial filter medium and filter module.
This patent application is currently assigned to NEENAH GESSNER GMBH. The applicant listed for this patent is MANN+HUMMEL GMBH, NEENAH GESSNER GMBH. Invention is credited to Ralf Blum, Ellen Buchta, Alexander Piry.
Application Number | 20140157990 14/096745 |
Document ID | / |
Family ID | 46208062 |
Filed Date | 2014-06-12 |
United States Patent
Application |
20140157990 |
Kind Code |
A1 |
Piry; Alexander ; et
al. |
June 12, 2014 |
Antimicrobial Filter Medium and Filter Module
Abstract
A filter medium with antimicrobial action, in particular for
filtering air for the interior area of motor vehicles, consisting
of at least one first filter layer where pollutants can be
retained, and a second filter layer adjacent to the first filter
layer is provided. The second filter layer is attached to the
on-flow side of the first filter layer and contains antimicrobial
agents.
Inventors: |
Piry; Alexander;
(Schwaebisch-Gmuend, DE) ; Blum; Ralf; (Aham,
DE) ; Buchta; Ellen; (Rosenheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NEENAH GESSNER GMBH
MANN+HUMMEL GMBH |
Bruckmuehl
Ludwigsburg |
|
DE
DE |
|
|
Assignee: |
NEENAH GESSNER GMBH
Bruckmuehl
DE
MANN+HUMMEL GMBH
Ludwigsburg
DE
|
Family ID: |
46208062 |
Appl. No.: |
14/096745 |
Filed: |
December 4, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2012/060501 |
Jun 4, 2012 |
|
|
|
14096745 |
|
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Current U.S.
Class: |
96/226 |
Current CPC
Class: |
A61L 2209/14 20130101;
B01D 2275/10 20130101; A61L 9/16 20130101; B01D 46/0028 20130101;
B01D 2239/0407 20130101 |
Class at
Publication: |
96/226 |
International
Class: |
B01D 46/00 20060101
B01D046/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 6, 2011 |
DE |
10 2011 104 628.7 |
Claims
1. A filter medium of a cabin air filter of a motor vehicle, the
filter medium comprising: a first filter layer operative to filter
and retain contaminants removed from an airflow stream; and a
second filter layer arranged to overlay the first filter layer;
wherein the second filter layer is attached onto an inflow side of
the first filter layer; wherein the second filter layer includes
contains antimicrobial substances.
2. The filter medium according to claim 1, wherein the second
filter layer is immediately adjacent to and abutting against the
first filter layer without interposing intermediate layers.
3. The filter medium according to claim 1, wherein the
antimicrobial substance is zinc pyrithione and/or
octa-isothiazolone.
4. The filter medium according to claim 1, wherein the second
filter layer additionally includes nano silver as a antimicrobial
substance.
5. The filter medium according to claim 1, wherein the second
filter layer additionally includes at least one antimicrobial
metals or metal compounds selected from the group consisting of:
copper and aluminum compounds.
6. The filter medium according to claim 1, wherein the second
filter layer additionally comprises substances selected from the
group consisting of: 2-bromo-2-nitropropane-1,3-diol, isothiazoline
compounds, benzoic acid and its derivatives, benzalkonium halides,
water-soluble coenzymes, oil-soluble coenzymes, plant extracts,
antibiotics, biocidal metals, aliphatic and aromatic fatty acids,
and quaternary surfactants.
7. The filter medium according to claim 1, wherein the
antimicrobial substances and/or additional biocidal substances can
be applied by spray application, slop padding or by means of a
foulard machine.
8. The filter medium according to claim 1, wherein the filter
medium consists of only two overlaid layers.
9. The filter medium according to claim 1, wherein the filter
medium consists of three overlaid layers abutting.
10. The filter medium according to claim 1, wherein the
antimicrobial substances or additional bactericidal substances are
added to the second layer directly during manufacture of the second
filter layer.
11. The filter medium according to claim 1, wherein the
antimicrobial substances or additional bactericidal substances are
added into the second filter layer after manufacture If the second
filter layer.
12. A motor vehicle cabin filter comprising the filter medium
according to claim 1.
13. The motor vehicle cabin filter according to claim 12, wherein
the filter medium is folded or undulated.
14. The motor vehicle cabin filter according to claim 12, wherein
the filter medium is provided on at least one side with a lateral
band of nonwoven; or wherein the filter medium is embedded by
injection molding in a plastic frame.
15. The motor vehicle cabin filter according to claim 13, wherein
the folded or undulated filter medium is provided on at least one
of its terminal edges with a lateral band of nonwoven.
16. A filter module of a motor vehicle cabin air conditioning
device, comprising: a filter receptacle or a filter housing; a
motor vehicle cabin filter according to claim 12 arranged within
the filter receptacle or a filter housing.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of
international application No. PCT/EP2012/060501 having an
international filing date of Jun. 4, 2012 and designating the
United States, the international application claiming a priority
date of Jun. 6, 2011, based on prior filed German patent
application No. 10 2011 104 628.7, the entire contents of the
aforesaid international application and the aforesaid German patent
application being incorporated herein by reference in their
entirety.
TECHNICAL FIELD
[0002] The present invention concerns generally a filter medium. In
particular, it concerns a filter medium with antimicrobial action.
Especially, it concerns a filter medium and a filter element
comprising such a filter medium for filtering air for the cabin of
a motor vehicle, i.e., a motor vehicle cabin filter. Moreover, the
invention concerns a filter module.
BACKGROUND OF THE INVENTION
[0003] Filter elements produced from filter media serve for
filtering fluid flows or gaseous media, for example, for filtering
an air flow which is supplied to the vehicle cabin of a motor
vehicle. Even though it is applicable to any type of filter
elements, the present invention and problem to be solved by it will
be described in the following in connection with a filter medium or
filter element for filtering air for the cabin of a motor vehicle.
In the following, such filters are referred to as motor vehicle
cabin filters for short.
[0004] The increasing air pollution, in particular in big cities,
in combination with the use of modern air conditioning systems
makes it desirable and also necessary to filter by means of a
suitable filter the air that is supplied from the exterior into the
cabin of a motor vehicle and that is processed and air-conditioned.
For this purpose, for example, particle filters or odor filters or
alternatively also combinations thereof are conceivable which are
to filter out the particles contained in the air as well as
inherent odors from the ambient air as much as possible and to
adsorb materials of the ambient air. Such filters for filtering air
for the cabin of a motor vehicle are generally known in a plurality
of embodiments and variants so that their configuration and
function will only be briefly addressed in the following.
[0005] Since the efficiency of filters depends in particular on the
size of the surface area of the filter that is flowed through by
the air, for motor vehicle cabin filters primarily zigzag-shaped
folded filter media are used that are also often referred to as
pleated filter media. In this way, due to the folding of the
employed filter medium, depending on the height of the folds and
the fold spacing of the various fold sections of the filter medium,
an effective enlargement of the filter surface area flowed through
by the air flow can be provided.
[0006] As already mentioned, due to the increasing air pollution,
increasingly more pollutants are present in the environment of a
motor vehicle so that the motor vehicle cabin filter is exposed to
an increasing load. These pollutants can be, for example, dust and
soot particles as well as pollen, bacterial spores and fungal
spores, bacteria and fungi. Some metabolic products of the
microorganisms are known to constitute allergic substances for the
human respiratory system. In some individuals, they can cause
asthma attacks and it is proven that they can cause an
immunological defense reaction.
[0007] US 2003/0 116 2022 A1 describes an air filter for
air-conditioning systems as they are used in offices, apartment
buildings and buildings for medical services such as hospitals and
medical care homes. The filter comprises a composition that
contains a biocide that is not bonded to the filter surface but is
adapted such that it can migrate through the fine dust that is
collecting on the filter so that the pollutant particles are coated
with the biocide. Suitable biocides are, for example,
2-bromo-2-nitropropane-1,3-diol, isothiazoline compounds, benzoic
acid, benzalkonium halides and the like.
[0008] US 2006/0021302 A1 discloses an antimicrobial air filter
whose filtration medium contains a "prophylactic" compound that can
be used to reduce the number of microbial organisms. The
"prophylactic" compound is introduced as a separate layer adjacent
to the pleated filter medium. The "prophylactic" compound may be
water-soluble coenzymes, oil-soluble coenzymes, plant extracts,
antibiotics, biocidal metals, aliphatic and aromatic fatty acids,
and the like.
[0009] WO 2006/003515 A1 discloses an air treatment device for a
particle filter of an air conditioning device of a motor vehicle.
The device is comprised of a permeable container that contains a
volatile treatment agent. The container is attached to the particle
filter.
[0010] US 2005/0079379 A1 discloses a cover fabric with at least
one fabric web that comprises an electrostatically charged
meltblown fiber nonwoven nap that is treated with a fluorine
chemical with a weak cationic emulsifying agent in order to reduce
the surface energy of the fibers to thereby minimize penetration
and wetting by oily mists and maintain thereby the effect of the
electrostatic charges imparted to the fibers. The fibers can
contain polyvinyl-N-pyridinium bromide. The fabric is used for face
masks and protective clothing. Use in vehicle cabin filters is not
proposed.
[0011] Finally, EP 1 882 511 A1 discloses a filter medium with
bactericidal effect in particular for filtering air for the cabin
of motor vehicles, comprised of at least one filter layer in which
contaminants are retainable and a bactericidal filter layer which
is downstream of this filter layer and is arranged on the clean air
side of the at least one filter layer and is spaced by a spacer
layer from the at least one filter layer.
[0012] A disadvantage of the solutions disclosed in the prior art
is, on the one hand, that they cannot be applied easily to motor
vehicle cabin filters and, on the other hand, that they cannot
effectively prevent growth of microorganisms on the filter medium
and in particular cannot prevent penetration of growth. Moreover,
growth, in particular of fungi or fungal spores, is not prevented
or only prevented to a minimal extent by the disclosed solutions.
Some of the disclosed biocidal agents show an effectiveness only
against certain microorganisms, for example, bacteria, but not
against molds; for others, an effective inhibition of microbial
growth is not ensured by the application of the biocides and the
construction of the filter medium.
SUMMARY OF THE INVENTION
[0013] An object of the present invention is to provide a filter
medium with antimicrobial action that avoids the aforementioned
disadvantages of the prior art. Moreover, the present invention
provides the possibility that an already existing filter medium can
be furnished with an additional antimicrobial layer without the
filtration efficiency being changed.
[0014] These and further objects are solved by a filter medium with
antimicrobial action comprising a first filter layer in which
contaminants can be retained and a second filter layer that
contains antimicrobial substances and is adjacent to the first
filter layer at the inflow side of the first filter layer.
[0015] The first filter layer can be a nonwoven, in particular a
meltblown nonwoven.
[0016] Such a filter medium can be used in particular for filtering
air for the cabin of motor vehicles. Other fields of use are
however also conceivable, for example, in air conditioning devices
for building services or also generally in filter systems, for
example, in which a particle filter layer or a second filter layer
is to be protected, in particular against microorganisms such as
fungi or fungal spores, in particular molds or mold spores,
bacteria or algae and in particular those in living, reproductive
or propagating form.
[0017] As an antimicrobial agent, zinc pyrithione can be used in
particular. Alternatively or additionally, octa-isothiazolone can
be used as an antimicrobial agent. The second filter layer can
contain additionally antimicrobial substances on the basis of nano
silver. The second filter layer can additionally contain
antimicrobial metals and metal compounds, in particular silver,
copper and aluminum compounds and/or
2-bromo-2-nitropropane-1,3-diol, further isothiazoline compounds,
benzoic acid and its derivatives, benzalkonium halides,
water-soluble coenzymes, oil-soluble coenzymes, plant extracts,
antibiotics, biocidal metals, aliphatic and/or aromatic fatty
acids, and/or quaternary surfactants as antimicrobial
substances.
[0018] The antimicrobial substances and/or additional biocidal
substances can preferably be applied by spray application, slop
padding or by means of a foulard machine.
[0019] The filter medium itself can be of a two-layer or
three-layer configuration. In the sequence of through-flow, for
example, a particle filter layer and an odor filter layer,
comprising active carbon, may follow behind the antimicrobial
layer. Alternatively, an odor filter layer and then a particle
filter layer can follow behind the antimicrobial layer.
[0020] The antimicrobial substances or the additional bactericidal
substances can be added directly when producing the second filter
layer. Alternatively or in combination, the antimicrobial
substances or the additional bactericidal substances can be
introduced subsequently into the second filter layer.
[0021] Such a filter medium is in particular suitable for a motor
vehicle cabin filter. In this connection, the filter medium is
preferably folded or undulated for increasing the surface area. In
different embodiments, the folded or undulated filter medium can be
provided on at least one side with a lateral band of nonwoven or
can be embedded by injection molding into a plastic frame. The
folded or undulated filter medium can have at least at one of its
terminal edges, these are the sides of the folded or undulated
filter medium that have a zigzag or undulated shape, a lateral
band, in particular a lateral band of nonwoven.
[0022] A motor vehicle cabin filter with the described medium can
be used as an exchangeable filter element in a filter module, in
particular the filter module of a motor vehicle air conditioning
device, comprising a filter receptacle or a filter housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying Figures, where like reference numerals
refer to identical or functionally similar elements throughout the
separate views and which together with the detailed description
below are incorporated in and form part of the specification, serve
to further illustrate various embodiments and to explain various
principles and advantages all in accordance with the present
invention.
[0024] Features of the present invention, which are believed to be
novel, are set forth in the drawings and more particularly in the
appended claims. The invention, together with the further objects
and advantages thereof, may be best understood with reference to
the following description, taken in conjunction with the
accompanying drawings. The drawings show a form of the invention
that is presently preferred; however, the invention is not limited
to the precise arrangement shown in the drawings.
[0025] FIG. 1 schematically depicts a two-layer configuration of
the filter medium according to the invention; and
[0026] FIG. 2 schematically depicts a three-layer configuration of
the filter medium according to the invention.
[0027] Skilled artisans will appreciate that elements in the
figures are illustrated for simplicity and clarity and have not
necessarily been drawn to scale. For example, the dimensions of
some of the elements in the figures may be exaggerated relative to
other elements to help to improve understanding of embodiments of
the present invention.
DETAILED DESCRIPTION
[0028] The medium according to the invention can be used, for
example, in cabin filters for motor vehicles. Further fields of
application are vacuum cleaner filters, filter elements for
building and stationary air conditioning devices, filter elements
for air purifiers, respiratory filters and the like.
[0029] In the following, the invention will be explained based on
the example of a cabin air filter element for a motor vehicle.
However, to a person of skill in the art it is readily apparent
that the invention is not limited thereto but, as already mentioned
above, can also be used in other fields.
[0030] The filter medium according to the invention is capable of
killing microorganisms, in particular fungi or fungal spores, and
at the same time of preventing effectively growth of bacteria,
fungi, and other microorganisms on the filter medium and in
particular of preventing effectively penetration of growth. The
term penetration of growth means the propagation of mycel-forming
microorganisms through a barrier layer, for example, a biocidal
layer. This can also happen in connection with bacteria that
propagate through this layer.
[0031] It is proposed according to the invention to design a filter
medium with antimicrobial action in such a way that a second filter
layer containing antimicrobial substances is mounted on the inflow
side of a first filter layer that is adjacent to the second filter
layer and that can retain contaminants. Accordingly, penetration of
growth even of mycel-forming microorganisms is effectively
prevented. The mold spores are retained because of their size
(2-100 .mu.m, typically 2-10 .mu.m) partially by the antimicrobial
layer or impinge on the filter layer furnished with the
antimicrobial substance and can therefore be inactivated or
inhibited in their growth. This is the great advantage relative to
a downstream antimicrobial filter layer because in this case the
spores from the ambient air are retained mainly in the upstream
particle layer and can germinate therein.
[0032] The filter medium according to the invention is typically
constructed such that the antimicrobial layer, i.e., the second
filter layer comprising antimicrobial substances, is mounted as an
additional layer (medium layer) on a medium. The antimicrobial
layer has also a filter action and can optionally be used also as a
single layer variant. In this context, the medium can either be
designed of a two-layer or three-layer configuration. FIG. 1 shows
a two-layer configuration of a particle filter medium 2 (first
filter layer) and a second filter layer 4 applied thereon which
contains antimicrobial substances. The first filter layer 2 can
optionally have a graduated configuration, i.e., in cross-section
in the flow direction can have a decreasing or increasing fiber
diameter and/or can contain nanofibers that improve primarily the
separating performance in regard to fine particles. FIG. 2 shows a
three-layer configuration of a fine fiber layer 6 which has been
produced, for example, according to the meltblown process, and a
further fiber layer 8 that due to its mechanical strength is also
referred to as a support and on which the second antimicrobial
fiber layer 4 is applied.
[0033] The antimicrobial support can be provided with different
microbial substances, for example, silver, copper, aluminum
compounds. A particularly advantageous microbial substance is Zn
pyrithione because it has a significant fungi-inhibiting effect and
a very minimal solubility in water. A further preferred substance
is octa-isothiazolone. Also, a finish on the basis of nano silver
and enzymatically, chemically acting substances is possible, for
example, 2-bromo-2-nitropropane-1,3-diol, isothiazoline compounds,
benzoic acid and benzoic acid derivatives, benzalkonium halides,
water-soluble and oil-soluble coenzymes, plant extracts, further
biocidal metals, aliphatic and aromatic fatty acids, as well as
quaternary surfactants, wherein the substances can be used as a
further option as well as in combination with Zn pyrithione.
Different grammages can be used for the second filter layer.
[0034] Furnishing the second filter layer with the antimicrobial or
biocidal substances can be performed by means of different
processes, for example, by spray application, slop padding or by
means of a foulard machine. The antimicrobial layer is
advantageously applied to the inflow side. Due to the afore
described three-layer configuration, negative interactions between
active substance and the functional particle fiber layer can be
avoided in this way. Because of the special three-layer sandwich
configuration, it is possible to protect the actual particle filter
layer and to ensure in this way a high filtration efficiency. Also,
the sandwich configuration has the advantage that in this way
different filter media that can be used in cabin filters of motor
vehicles can be furnished with an additional antimicrobial layer
that can be offered as an additional option for the existing
filters (in case of a motor vehicle cabin filters a plurality of
different filter media are employed that are tailored to regional
as well as manufacturer-specific requirements). Moreover, with the
additional antimicrobial layer, tailored solutions for different
fields of applications can be achieved. Also, for example, in
different climatic conditions, different microorganisms play a role
in connection with the growth on the filter medium so that the
antimicrobial substances applied to the second filter layer can be
selected appropriately and, in addition, the grammage can be
varied.
[0035] In addition, the layer (meltblown) that determines the
filtration efficiency can be finished in a master batch with
antimicrobial substances or the medium can exhibit an increased
antimicrobial action by means of additional introduction of
antimicrobial fibers produced by a master batch.
[0036] The subsequent application of the substance in comparison to
the addition directly during fiber manufacture (master batch) has
the advantage that reduced substance concentrations are sufficient
because the substance is externally present on the fiber and
therefore is in direct contact with the microorganisms. An
advantage of master batch production or addition of fibers produced
by a master batch process resides in that the antimicrobial
substances are anchored particularly strongly on the fiber.
[0037] The filter medium according to the invention can be used to
produce a filter module, in particular a particle and/or odor
filter, with a filter housing, wherein the filter medium is
inserted into the filter housing.
[0038] In the foregoing specification, specific embodiments of the
present invention have been described. However, one of ordinary
skill in the art appreciates that various modifications and changes
can be made without departing from the scope of the present
invention as set forth in the claims below. Accordingly, the
specification and figures are to be regarded in an illustrative
rather than a restrictive sense, and all such modifications are
intended to be included within the scope of the present invention.
The benefits, advantages, solutions to problems, and any element(s)
that may cause any benefit, advantage, or solution to occur or
become more pronounced are not to be construed as a critical,
required, or essential features or elements of any or all the
claims. The invention is defined solely by the appended claims
including any amendments made during the pendency of this
application and all equivalents of those claims as issued.
* * * * *