U.S. patent application number 12/807662 was filed with the patent office on 2012-03-15 for pleated filtering face piece respirator.
This patent application is currently assigned to Moldex-Metric, Inc.. Invention is credited to Mark Magidson, Crest Turdjian.
Application Number | 20120060843 12/807662 |
Document ID | / |
Family ID | 45805453 |
Filed Date | 2012-03-15 |
United States Patent
Application |
20120060843 |
Kind Code |
A1 |
Magidson; Mark ; et
al. |
March 15, 2012 |
Pleated filtering face piece respirator
Abstract
A pleated molded filtering face piece respirator to be worn upon
the face of a wearer and for providing filtering including at least
one layer of moldable flexible plastic material formed from
openwork flexible plastic material for providing a plurality of
perforations for allowing for the free passage of air through the
openwork plastic. A layer of moldable filter material for filtering
impurities in the air, the one layer of flexible plastic material
formed from openwork flexible plastic material and the layer of
filter material for filtering impurities in the air lying one on
top of the other to form a moldable multilayer of flexible plastic
material and filter material. The moldable multilayer of flexible
plastic material and filter material are pleated into pleated
material and molded to form the pleated filtering face piece
respirator to a desired configuration where the one layer of
openwork flexible plastic material forms a support layer to carry
the layer of filter material.
Inventors: |
Magidson; Mark; (Los
Angeles, CA) ; Turdjian; Crest; (Los Angeles,
CA) |
Assignee: |
Moldex-Metric, Inc.
|
Family ID: |
45805453 |
Appl. No.: |
12/807662 |
Filed: |
September 9, 2010 |
Current U.S.
Class: |
128/206.19 ;
264/257 |
Current CPC
Class: |
B29C 43/021 20130101;
B29C 43/203 20130101; A41D 13/1115 20130101; A41D 13/1146 20130101;
A62B 23/025 20130101 |
Class at
Publication: |
128/206.19 ;
264/257 |
International
Class: |
A62B 7/10 20060101
A62B007/10; B29C 43/20 20060101 B29C043/20 |
Claims
1. A method of making a pleated filtering face piece respirator to
be worn upon the face of a wearer and for providing filtering
including the following steps, providing at least one layer of
flexible plastic material formed from openwork flexible plastic
material for providing a plurality of perforations for allowing for
the free passage of air through the openwork plastic, providing a
layer of filter material for filtering impurities in the air,
positioning the at least one layer of flexible plastic material
formed from openwork flexible plastic material and the layer of
filter material for filtering impurities in the air to lie one on
top of the other to form a multilayer of flexible plastic material
and filter material, providing a pleater for pleating sheet
material into pleated material, moving the multilayer of flexible
plastic material and filter material to the pleater, pleating the
multilayer of flexible plastic material and filter material to form
a pleated composite layer of flexible plastic material and filter
material, providing male and female molding members having a mold
configuration conforming generally to the contours of the face of
the wearer, moving the pleated composite layer of flexible plastic
material and filter material, between the male and female molding
members, and pressing the male and female molding members together
to form the pleated filtering face piece respirator to the desired
configuration by molding the at least one layer of openwork
flexible plastic material to form a support layer to carry the
layer of filter material
2. The method of claim 1 wherein two layers of openwork flexible
plastic material are provided and wherein the layer of filter
material is sandwiched between the layers of openwork flexible
plastic when the male and female molding members are pressed
together.
3. The method of claim 2 additionally including the step of
providing a layer of soft fabric and positioning the layer of soft
fabric adjacent the inner one of the two layers of openwork
flexible plastic material prior to the step of pleating for
covering the inner surface of the pleated filtering face piece
respirator.
4. The method of claim 2 additionally including the step of
providing a layer of soft elastic fabric and positioning the layer
of soft fabric adjacent the inner one of the two layers of openwork
flexible plastic material after the step of pleating for covering
the inner surface of the pleated filtering face piece respirator
with the soft elastic material.
5. The method of claim 4 wherein the soft elastic material is
formed as a propylene-based elastomer.
6. The method of claim 4 wherein the soft elastic material is
formed as a perforated spun bond.
7. The method of claim 2 additionally including the step of heating
the peripheral edges of the pleated layers of openwork flexible
plastic and filter material to seal the peripheral edge of the
filtering face piece respirator.
8. The method of claim 2 additionally including the step of
precutting the pleated layer of openwork flexible plastic and
filter material to a particular configuration the prior to the
molding step.
9. The method of claim 2 additionally including the step of
attaching a flange around the peripheral edge of the filtering face
piece respirator.
10. The method of claim 1 additionally including the step of
providing a layer of soft fabric and positioning the layer of soft
fabric adjacent the inner one of the layers of openwork flexible
plastic material and filter material prior to the step of pleating
for covering the inner surface of the pleated filtering face piece
respirator.
11. The method of claim 1 additionally including the step of
providing a layer of soft elastic fabric and positioning the layer
of soft fabric adjacent the inner one of the layers of openwork
flexible plastic material and filter material after the step of
pleating for covering the inner surface of the pleated filtering
face piece respirator with the soft elastic material.
12. The method of claim 11 wherein the soft elastic material is
formed as a propylene-based elastomer.
13. The method of claim 11 wherein the soft elastic material is
formed as a perforated spun bond.
14. The method of claim 1 additionally including the step of
heating the peripheral edge of the at least one layer of openwork
flexible plastic material and filter material after the step of
molding to seal the peripheral edge of the pleated filtering face
piece respirator.
15. The method of claim 1 additionally including the step of
precutting the pleated layer of openwork flexible plastic and
filter material to a particular configuration the prior to the
molding step.
16. The method of claim 1 additionally including the step of
attaching a flange around the peripheral edge of the filtering face
piece respirator.
17. A pleated molded filtering face piece respirator to be worn
upon the face of a wearer and for providing filtering including, at
least one layer of moldable flexible plastic material formed from
openwork flexible plastic material for providing a plurality of
perforations for allowing for the free passage of air through the
openwork plastic, a layer of moldable filter material for filtering
impurities in the air, the at least one layer of flexible plastic
material formed from openwork flexible plastic material and the
layer of filter material for filtering impurities in the air lying
one on top of the other to form a moldable multilayer of flexible
plastic material and filter material, and wherein the moldable
multilayer of flexible plastic material and filter material are
pleated into pleated material and molded to form the pleated
filtering face piece respirator to a desired configuration wherein
the at least one layer of openwork flexible plastic material forms
a support layer to carry the layer of filter material.
18. The pleated molded filtering face piece respirator of claim 17
including two layers of openwork flexible plastic material and
wherein the layer of filter material is sandwiched between the two
layers of openwork flexible plastic when the two layers of openwork
flexible plastic material are molded to form the pleated filtering
face piece respirator.
19. The pleated molded filtering face piece respirator of claim 17
additionally including a layer of soft fabric and positioned
adjacent the inner one of the layers of openwork flexible plastic
material and filter material prior to pleating for covering the
inner surface of the pleated filtering face piece respirator.
20. The pleated molded filtering face piece respirator of claim 17
additionally including a layer of soft elastic fabric and
positioned adjacent the inner one of the layers of openwork
flexible plastic material after pleating for covering the inner
surface of the pleated filtering face piece respirator with the
soft elastic material.
21. The pleated molded filtering face piece respirator of claim 20
wherein the soft elastic material is a propylene-based
elastomer.
22. The pleated molded filtering face piece respirator of claim 20
wherein the soft elastic material is a perforated spun bond.
23. The pleated molded filtering face piece respirator of claim 17
additionally including a sealed peripheral edge of the pleated
filtering face piece respirator.
24. The pleated molded filtering face piece respirator of claim 17
additionally including a flange attached around the peripheral edge
of the filtering face piece respirator.
Description
[0001] The present invention relates to a pleated filtering face
piece respirator and in particular to a pleated filtering face
piece respirator formed from a plurality of layers and with the
individual layers serving different functions. In the filtering
face piece respirator of the present invention, at least one layer
is formed of an openwork pleated flexible plastic material and
serves as a support layer for carrying at least another layer of
pleated filter material. It will be appreciated that the pleats may
be close together or just slightly undulated so as to increase the
surface area of the filter material. In a particular embodiment of
the invention, a pair of layers of openwork pleated flexible
plastic material form the support for the pleated filter layer, and
with the layer of pleated filter material sandwiched in between the
layers of pleated openwork plastic material. The pleating of the
various layers of the filtering face piece respirator allow for the
filtering face piece respirator to conform and seal the filtering
face piece respirator at the periphery of the mask to the face of
the user while allowing the mask to expand within the periphery of
the mask in accordance with movements of the face of the user.
[0002] The great majority of molded filtering face piece
respirators are made from a flat layer, or multiple flat layers of
melt blown filter media that include carrier materials to protect
the media and provide a structure for the wearer. These
constructions are fairly rigid in nature, meaning that one cannot
stretch the materials significantly between any two fixed points on
the respirator.
[0003] Providing a flexible elastic structure for a filtering face
piece respirator would constitute an improvement over what as been
available in filtering face piece respirator design. The current
invention allows for flexibility in the face piece that before now
has not been available, as well as other structural advantages that
will greatly benefit the user.
[0004] Creating pleats in filter media is a process that has been
used extensively for filtration both for face pieces and other
filters as well, such as automotive air filters and
air-conditioning filters. While pleating has been used sparingly in
molded filtering face piece respirators, such constructions have
been relatively rigid or non-resilient in nature. Removing the
rigid materials from the pleated filter media, or forming the
materials in a way that creates both flexibility and resilience,
results in a significant step forward in filtering face piece
respirator constructional benefits. By encapsulating the media in a
resilient polymer netting, the construction has enough resilience
and structure to cause the pleated filter media to both easily
expand and easily contract during facial movement, allowing for
improved facial contact as well as allowing the respirator to
potentially fit a wider range of facial sizes. The resilient
polymer netting or nettings serving as the carrier for the filter
material is of sufficient resilience to return to its original
three dimensional form when not under stress but flexible enough to
conform to the facial movements of the user.
[0005] Additionally, the extra surface area provided by the pleats
has the benefit of improving filter performance by increasing
surface area, which not only has a direct relationship with ease of
breathing, but also allows the respirator to expand and contract,
and will fit a wider arrange of faces comfortably than a respirator
that does not have this structure.
[0006] The preferred construction consists of at least one layer of
melt-blown polypropylene filter media covered by at least one layer
of resilient plastic netting. A resilient polymer material
containing at least about 15% EVA is optimal, with a basis weight
of about 20 grams/sq. meter or higher, depending on the weight of
the desired filter media. When a high level of filtration is
required it is necessary to make the filter media of a higher basis
weight, either by using heavier melt blown media or using multiple
layers of lighter weight media. In the present invention a higher
weight filter media requires a higher weight plastic netting and
vice versa to provide the necessary balance of flexibility and
resilience.
[0007] The inner layer, which contacts the skin, is preferably
covered by a spun bond non-woven material that is traditionally
non-elastic in its stretch properties, however when pleated in
concert with the rest of the materials, the spun bond material
retains the resilience and spring like quality of the mesh covered
filter media.
[0008] Another embodiment attaches an unpleated spun bond material
to the periphery of the inner molded mask construction. However, in
this embodiment the spun bond material or fabric has significant
elongation properties that allow it to expand and contract with the
rest of the pleated mask during facial movement. Yet another
embodiment attaches either a foamed in place or welded soft flange
around the respirator's periphery or a portion of the periphery
that is stretchable enough to accommodate the respirator's
flexibility.
[0009] With the filtering face piece respirator of the present
invention, the use of the openwork pleated plastic material
provides for a flexible yet shape-retaining carrier support for the
pleated filter material. Moreover, since the pleated plastic
material has an openwork configuration that provides for a
plurality of perforations, the openwork pleated plastic material
allows for the generally unrestricted passage of a high volume of
air. Since the openwork pleated plastic allows for the passage of a
high volume of air, the filtering face piece respirator of the
present invention is comfortable to wear since the breathing of the
wearer is not unduly restricted.
[0010] The layer of pleated filter material may be of any of the
general types of filter material commonly used with filtering face
piece respirators for providing for the filtering of particular
impurities in the air. The filter material may be formed from
various types of filter materials, such as non-woven polyester
fiber, electrostatically charged polypropylene, activated charcoal
or other additives, various types of natural fibers and other
filter materials currently used. Many of the filter materials
currently used to provide the filter portion of filtering face
piece respirators cannot stand a high degree of heat since the heat
may reduce or eliminate the filtering properties of the material.
With the present invention, the filtering face piece respirator may
be formed using the method of U.S. Pat. No. 4,850,347 which patent
describes a technique that does not subject the filter material to
a high degree of heat, so that the filtering properties of the
filter material are not substantially affected.
[0011] With the filtering face piece respirator of the present
invention, the pleated filter material may be relatively thick and
yet still be properly supported by the carrier layers of
openwork-pleated plastic. In addition, the filter material
currently used may not be shape retaining or self supporting, so it
is necessary to use some sort of carrier means to provide for the
support of the pleated filter material.
[0012] In the pleated filtering face piece respirator of the
present invention, the openwork pleated plastic material may be
formed from a plastic sheet that has a pattern of openings or may
be formed from a sheet of woven material or may be formed from a
sheet of mesh material. In particular, the openwork plastic layer
may be formed from various plastic materials such as vinyl,
polyethylene, synthetic or real rubber or other materials or
combinations of materials. As an example, the openwork plastic
layer has been formed from ethyl vinyl acetate polypropylene
blend.
[0013] In a first particular embodiment of the present invention,
the pleated filtering face piece respirator is formed from four
layers of material and specifically includes a pair of openwork
flexible plastic layers serving to support a layer of filter
material in between the openwork plastic layers. A fourth inner
layer of a soft material serves as a layer positioned against the
face of the wearer of the mask. This soft material provides
additional comfort to the wearer of the filtering face piece
respirator. The fourth inner layer may be pleated with the other
layers or may be formed of a stretchable material that can expand
with expansion of the pleats as described above. In the simplest
embodiment of the invention, a single sheet of openwork pleated
flexible plastic is formed to carry and to act as a support for a
layer of pleated filter material.
[0014] The present invention therefore is directed to a pleated
filtering face piece respirator that allows for the use of
different types of filter material to provide for the desired
degree of filtering while at the same time allowing for a
considerable volume of air to pass to the wearer of the mask. The
pleated filtering face piece respirator of the present invention
includes at least a single layer of pleated openwork flexible
plastic material supporting and carrying at least one layer of
pleated filter material. The pleated filtering face piece
respirator of the present invention may include an additional layer
of pleated openwork plastic material to provide for additional
support and an additional layer of a soft fabric material to
provide for comfort. The present invention includes various means
for sealing the peripheral edge of the filtering face piece
respirator. A clearer understanding of the present invention will
be had with reference to the following description and drawings
wherein:
[0015] FIG. 1 is a perspective view of a first embodiment of a
pleated filtering face piece respirator constructed in accordance
with the teachings of the present invention;
[0016] FIG. 2 is a back view of the first embodiment of the
invention;
[0017] FIG. 3 is a side view of the first embodiment of the
invention;
[0018] FIG. 4 is a side cross-sectional view taken along lines 4-4
of FIG. 2;
[0019] FIG. 5 is a side cross-sectional view similar to FIG. 4 of
an alternate structure of the pleated filtering face piece
respirator of the present invention and including an inner
expandable spun bond layer;
[0020] FIG. 6 is a side cross-sectional view similar to FIG. 4 of
an alternate structure of the pleated filtering face piece
respirator of the present invention with a simpler
construction;
[0021] FIG. 7 illustrates a first method for forming the pleated
filtering face piece respirator of the present invention;
[0022] FIG. 8 illustrates a second method for forming the pleated
filtering face piece respirator of the present invention;
[0023] FIG. 9 is a perspective view of a second embodiment of a
pleated filtering face piece respirator constructed in accordance
with the teachings of the present invention;
[0024] FIG. 10 is a back view of the second embodiment of the
invention;
[0025] FIG. 11 is a top view of the second embodiment of the
invention; and
[0026] FIG. 12 illustrates an alternate elastic fabric
material.
[0027] FIGS. 1 through 6 illustrates first embodiment of the
pleated filtering face piece respirator of the present invention
with alternate constructions. As shown in FIGS. 1-3, the pleaded
respirator has the pleats oriented horizontally relative to the
face of the used of the respirator. The filtering face piece
respirator in one construction includes four layers of material.
Specifically, a pair of pleated openwork flexible plastic layers 10
and 12 that sandwich a layer of pleated filter material 14. A layer
of a soft fabric, which may be pleated fabric 16 as shown in FIG. 4
or un-pleated elastic fabric 18 as shown in FIG. 5, is positioned
on the inside surface of the filtering face piece respirator and
provides for additional comfort for the wearer of the filtering
face piece respirator. An elastic band 20 may be attached to the
side of the respirator and is used to support the filtering face
piece respirator in position against the face of the user.
[0028] The pleated openwork plastic layers 10 and 12 provide for
support layers to carry the filter material 14. In particular, the
openwork plastic layers may be formed from sheets that have a
plurality of openings therethrough to permit the free passage of
air. For example, the openwork plastic layers may be formed from a
perforated plastic material, a woven plastic material, a mesh
plastic material, etc. In general, the plastic material is of the
type that can be molded to a desired contour configuration and will
retain that configuration so as to support the filter material, yet
at the same time being flexible enough as shown by arrows 22 to
allow for the filtering face piece respirator to flex by opening
and closing movement of the pleats in the direction of the arrows
22 to conform to different facial contours and facial movements of
individual wearers of the mask. Specifically, the openwork plastic
layers may be composed of various types or combinations of plastic
materials such as vinyls, polyethylenes, synthetic rubber, etc.,
which allow for moldability to form the desired configuration yet
with flexibility to allow for the pleated shaped mask to fit the
face of individual wearers.
[0029] The filter layer 14 may be formed from any of the known
types of filter materials such as non-woven polyester fiber
material, electrostatically charged polypropylene, activated
charcoal, various natural fibers such as merino wool, or other
types of materials used for filtering. Many of these different
types of filter material cannot withstand high heat, since the high
heat would tend to destroy the filtering properties of the
material. The method of forming the filtering face piece respirator
as described in U.S. Pat. No. 4,850,347 may be used so the filter
layer 14 is not subjected to high heat.
[0030] In the construction of the first embodiment of the filtering
face piece respirator shown in FIGS. 1 through 4, the pleated inner
layer 16 of a soft fabric is provided for comfort. This layer may
be formed of material such as spun bond that will adhere to the
inner layer of openwork plastic during the molding process. An
alternate construction of the filtering face piece respirator is
shown in FIG. 5. In this construction the un-pleated inner layer 18
is also formed of a soft fabric for comfort. This layer may be
formed of material such as an elastic spun bond that will adhere to
the inner tops of the pleated layer of openwork plastic during the
molding process and can stretch to match opening and closing
movement of the pleated layers. As an example, the elastic spun
bond may be formed of propylene-based elastomers.
[0031] Other constructions of the first embodiment of the pleated
filtering face piece respirator of the present invention show
various means for sealing the peripheral edge portion of the
filtering face piece respirator to the face of the user. In FIG. 2,
a nosepiece 24 is shown to provide additional sealing around the
nose portion of the user. Also, as shown by dotted line flange
portion 26, a flange may be attached around the periphery of the
respirator to provide sealing to the face of the user. This
additional sealing provides for a closer fitting of the mask to the
face of the user. As an alternative to the flange shown in FIG. 2,
the edge portion of the filtering face piece respirator may be
sealed by an attached soft molded gasket member. This gasket member
would not only provide for a seal of the edge portion, thereby
preventing the layers from separating, but also the gasket may
provide for a tighter seal of the mask against the face of the
wearer. The gasket member may be attached to the edge portion after
the molding of the respirator or may be molded in place.
[0032] FIG. 6 illustrates a portion of a third alternate
construction of the first embodiment of the filtering face piece
respirator of the present invention and in particular shows a
pleated filtering face piece respirator having the simpler
construction than the first and second alternate constructions of
the first embodiment and includes just two layers of material.
Specifically, in the construction of FIG. 6, the first layer of
pleated openwork flexible plastic material 10 forms a support
carrier for the second layer of pleated filter material 14. The
layers 10 and 14 may be constructed using the materials described
above, and an elastic band may be attached so as to hold the
filtering face piece respirator in position.
[0033] It is to be appreciated that the structure of FIG. 6
contemplates the use of pleated filter material 14, which will at
least to some degree be held in place with the one layer of plastic
material even though the filter material is not sandwiched between
two layers of plastic material. As an example, if the layer of
filter material 14 is formed from a natural fiber, such as merino
wool, then this layer may be comfortably positioned against the
face of the wearer. It is also to be appreciated that the relative
positions of the layers 10 and 14 may be reversed and with the
filter material on the outside. Since the construction of the
filtering face piece respirator shown in FIG. 6 is simpler in
structure and materials, it would be less costly than the
constructions shown in FIGS. 1 through 5. However, the filtering
face piece respirator of FIG. 6 would not be able to withstand the
same degree of wear as the constructions of FIGS. 1 through 5.
[0034] FIG. 7 illustrates a first method of making the pleated
filtering face piece respirator of the present invention and
specifically a method of molding the filtering face piece
respirator to the desired contour configuration. In the method as
shown in FIG. 7, the filter material 14 may be provided in a roll
100, as a first step. As a second step, the filter material 14 may
be inserted between top and bottom sheets of openwork plastic
material 10 and 12, also supplied in rolls 102 and 104, for the
first and second embodiments of the invention. In the third simpler
embodiment of the invention, only plastic material 10 is used so
the roll 104 that contains the plastic material 12 is shown in
dotted line.
[0035] As a third step, soft fabric 16 in a roll 106 may be
inserted adjacent the plastic material 12 for the first embodiment
of the invention. The roll 106 is shown in dotted form since in the
second and third embodiments of the invention, the spun bond fabric
16 is not used. As the next step, all of the layers of material are
now brought to a pleater 108 to form the pleated multilayered
material that is used for molding the respirator of the present
invention. If the second embodiment of the invention is to be made,
then after pleating by the pleater 108, stretchable fabric 18 on a
roll 110 shown in dotted line is inserted as the next step prior to
forming the respirators.
[0036] In the next step, molds 112 and 114 in a forming station
116, are brought together to capture for the first and second
embodiments of the invention, the pleated sheets of plastic
material 10 and 12, the filter material 14 and the fabric 16 or 18,
so as to provide for molding of individual pleated filtering face
piece respirators. All of the particular embodiments of the pleated
filtering face piece respirator described above such as the third
embodiment and any variants may be made by the above method as long
as at least one layer of the openwork flexible plastic material is
used to carry and support the filter material so as to allow for a
high volume of air to pass through the opening in the pleated
openwork plastic material.
[0037] As a final step, the individual filtering face piece
respirators may be cut from the large sheets and the edges may be
sealed using sealing and cutting members 118 and 120 in a sealing
and cutting station 122. This forms the individual pleated face
piece respirators of the present invention as shown by individual
pleated face piece respirators 124.
[0038] As an alternative to the method of FIG. 7, the method of
FIG. 8 may be used wherein multilayered pleated material 126 in any
of its alternate forms as shown in FIG. 7 may be stored in a roll
128. The pleated material 126 may then in a first step pass through
a cutting station 130 to be cut into individual pieces for forming
into pleated face piece respirators 124. This is accomplished using
the same forming and sealing and cutting stations 116 and 122 of
FIG. 7.
[0039] FIGS. 9 through 11 illustrate a second embodiment of the
pleated filtering face piece respirator of the present invention
with the pleats oriented vertically relative to the face of the
user of the respirator. The various materials used are the same for
the constructions of the second embodiment as for the constructions
of the first embodiment and the same reference numerals are used
for both. The pleated filtering face piece respirator of FIGS. 9-11
in one construction includes four layers of material. Specifically,
a pair of pleated openwork flexible plastic layers 10 and 12 can
sandwich a layer of pleated filter material 14. A layer of a soft
fabric, which may be pleated fabric 16 as shown in FIG. 4 or
un-pleated elastic fabric 18 as shown in FIG. 5, is positioned on
the inside surface of the filtering face piece respirator and
provides for additional comfort for the wearer of the pleated
filtering face piece respirator.
[0040] An elastic band 20 may be attached to the side of the
respirator and is used to support the filtering face piece
respirator in position against the face of the user. In the first
embodiment, the elastic band 20 is attached by passing the band
through a folded over portion of the respirator while in the second
embodiment, the band is stapled onto the periphery of the
respirator.
[0041] In the construction of the second embodiment of the
filtering face piece respirator shown in FIGS. 9 through 11, the
pleated inner layer 16 of the soft fabric is provided for comfort.
This layer may be formed of material such as spun bond that will
adhere to the inner layer of openwork plastic during the molding
process. An alternate construction of the filtering face piece
respirator is shown in FIG. 5. In this construction the un-pleated
inner layer 18 is also formed of a soft fabric for comfort. This
layer may be formed of material such as an elastic spun bond that
will adhere to the inner tops of the pleated layer of openwork
plastic during the molding process and can stretch to match opening
and closing movement of the pleated layers. As an example, the
elastic spun bond may be formed of propylene-based elastomers. As
an alternative to the use of this specific material, ordinary spun
bond fabric can be made to be elastic by perforating the spun bond
in the manner shown in FIG. 12. This allows the perforated fabric
to expand in the direction shown by the arrows 200.
[0042] In FIG. 2, as shown by dotted line flange portion 26, a
flange may be attached around the periphery of the respirator to
provide sealing to the face of the user. FIG. 10 illustrates this
flange 26 providing for a closer fitting of the mask to the face of
the user.
[0043] FIG. 6 illustrates a portion of a third alternate
construction of the first embodiment of the filtering face piece
respirator of the present invention that may also be used for the
second embodiment of the invention. The second embodiment of the
invention may be manufactured using the methods illustrated in
FIGS. 7 and 8. In addition, the improved pleated filtering face
piece respirator of the present invention may also be constructed
using pleats running in multiple vertical directions to provide
flexibility in multiple directions. The pleats may be in different
portions of the respirator or may be superimposed. The pleats may
be horizontal, vertical or at any angular direction.
[0044] The present invention, therefore, provides for an improved
filtering face piece respirator providing for both desirable filter
characteristics yet allowing the masks to conform to the
configuration of the face of the wearer and also allowing for a
relatively high volume of air to pass through the mask to the
wearer of the mask.
[0045] Although the invention has been described with reference to
particular embodiments, it is to be appreciated that various
adaptations and modifications may be made, and the invention is
only to be limited by the appended claims.
* * * * *