U.S. patent application number 09/438332 was filed with the patent office on 2003-07-10 for allergen barrier fabrics.
Invention is credited to CARR, GREGORY DEWAYNE, WOLYNES, EARLE.
Application Number | 20030129904 09/438332 |
Document ID | / |
Family ID | 23740241 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030129904 |
Kind Code |
A1 |
WOLYNES, EARLE ; et
al. |
July 10, 2003 |
ALLERGEN BARRIER FABRICS
Abstract
Fabrics having enhanced allergen barrier capabilities are
described. The fabrics are woven and calendered, and desirably face
finished to provide lightweight, thin fabrics having good aesthetic
properties. The fabrics also have good moisture vapor transport
characteristics and superior allergen barrier capabilities, and in
particular, superior barrier capabilities for cat dander allergen
(representing smaller allergen particle size), as well as dust mite
allergen. Protective coverings made from the fabrics and methods
for their production are also described.
Inventors: |
WOLYNES, EARLE;
(SPARTANBURG, SC) ; CARR, GREGORY DEWAYNE; (MOORE,
SC) |
Correspondence
Address: |
MILLIKEN & COMPANY
920 MILLIKEN RD
PO BOX 1926
SPARTANBURG
SC
29304
US
|
Family ID: |
23740241 |
Appl. No.: |
09/438332 |
Filed: |
November 13, 1999 |
Current U.S.
Class: |
442/211 ;
442/123; 442/190; 442/208; 442/216; 442/76; 442/77; 5/699 |
Current CPC
Class: |
D03D 15/33 20210101;
D03D 15/49 20210101; Y10T 442/3244 20150401; D03D 15/283 20210101;
D06C 27/00 20130101; Y10T 442/2148 20150401; Y10T 442/2525
20150401; Y10T 442/2139 20150401; Y10T 442/322 20150401; Y10T
442/3285 20150401; D10B 2331/04 20130101; D10B 2201/02 20130101;
D03D 15/217 20210101; Y10T 442/3073 20150401 |
Class at
Publication: |
442/211 ; 442/76;
442/77; 442/123; 442/208; 442/216; 442/190; 5/699 |
International
Class: |
D03D 015/00 |
Claims
We claim:
1. An allergen barrier fabric comprising a substantially
all-polyester, woven material having a warp yarn set and a fill
yarn set, said material allowing the flow through of less than
about 1 nanogram of Fel d1 cat dander allergen when subjected to a
Fel d1 airflow test.
2. An allergen barrier fabric according to claim 1, wherein said
material allows flow through of less than about 0.5 nanograms of
Fel d1 cat dander allergen.
3. An allergen barrier fabric according to claim 1, wherein said
material allows flow through of less than about 0.31 nanograms, so
as to provide an effective barrier to the transfer of cat dander
allergen.
4. An allergen barrier fabric according to claim 1, wherein said
woven material is calendered.
5. An allergen barrier fabric according to claim 1, wherein at
least one of said warp and fill yarn sets comprises microdenier
yarns.
6. An allergen barrier fabric according to claim 1, wherein said
material has a moisture vapor transmission rate of at least about
400 g/sq m/24 hrs.
7. An allergen barrier fabric according to claim 1, wherein said
fabric has a moisture vapor transmission rate of at least about 430
g/sq m/24 hrs.
8. An allergen barrier fabric according to claim 1, wherein said
fabric has a weight of about 3 ounces or less per square yard.
9. An allergen barrier fabric according to claim 1, wherein said
fabric has a thickness of about 8 mils or less.
10. An allergen barrier fabric according to claim 1, wherein said
fabric has a thickness of about 7 mils or less.
11. An allergen barrier fabric according to claim 1, wherein at
least one of said warp and fill yarn sets comprises microdenier
yarns, said material has a moisture vapor transmission rate of at
least about 425 g/sq m/24 hrs, a weight of about 3 oz/sq yd or
less, and allows a flow through of about 0.31 nanograms or less of
Fel d1 cat dander when subjected to a Fel d1 airflow test, so as to
be an effective barrier against cat dander allergen.
12. An allergen barrier fabric comprising a polyester/cotton
calendered woven material having a weight of about 4 oz/sq yd or
less, wherein said material allows for the flow through of less
than about 10 nanograms of Fel d1 cat dander when subjected to a
Fel d1 airflow test.
13. An allergen barrier fabric according to claim 12, wherein said
material allows for the flow through of less than about 8 nanograms
of Fel d1 cat dander when subjected to a Fel d1 airflow test.
14. An allergen barrier fabric according to claim 12, wherein said
material has a moisture vapor transmission rate of at least about
400 g/sq m124 hrs.
15. An allergen barrier fabric according to claim 12, wherein said
material has a thickness of about 10 mils or less.
16. An allergen barrier fabric according to claim 12, wherein said
material is calendered.
17. A protective covering comprising the fabric of claim 1.
18. A protective covering comprising a calendered woven
substantially all-polyester fabric having a moisture vapor
transmission rate of at least about 400 g/sq m/24 hrs, and allowing
a flow through of less than about 1 nanogram of Fel d1 cat dander
allergen when subjected to a Fel d1 airflow test.
19. A protective covering according to claim 16, wherein said
material allows flow through of less than about 0.5 nanograms of
Fel d1 cat dander allergen.
20. A protective covering according to claim 16, wherein said
material allows flow through of less than about 0.31 nanograms, so
as to provide an effective barrier to the transfer of cat dander
allergen.
Description
FIELD OF THE INVENTION
[0001] This invention generally relates to protective fabrics and
covers. More specifically, the invention relates to protective
fabrics which have enhanced allergen barrier capabilities,
rendering them particularly useful as a barrier to allergens and
the like.
BACKGROUND
[0002] Many people suffer from allergies caused by airborne fine
particulate matter such as pollen, dust, house dust mites and their
fecal matter, animal and human dander, molds, inorganic dust, and
the like. In fact, it has been found that the condition of many
asthma sufferers can be exacerbated by, and in some cases even
caused as a result of, exposure to common house dust and the dust
mites that live in the dust. In addition, the problems associated
with human allergies to animal dander are widely known; as a
result, many individuals are unable to have dander-producing house
pets.
[0003] The house dust mite (Dermatophagoides pteronyssimus), which
is a member of the spider family, measures about 0.3 mm across and
to the naked eye, is indistinguishable from a speck of dust. It
accounts for a large percentage of the mite population in samples
taken from homes. Because the house dust mites require a moist
environment and feed on such things as human skin, they are
typically concentrated in high numbers in and around beds and
bedding items.
[0004] Due to its relatively large size, it has been found that the
dust mite itself does not generally tend to cause an allergic
reaction in most individuals. However its fecal pellet, which
measures only about 20 microns (20/100 mm) in diameter, is a common
cause of allergic reactions in humans. This mite fecal pellet,
which is generally referred to as Der p1 in allergen discussions,
easily becomes airborne where it can be readily inhaled and
deposited on the inner lining of the respiratory tract of a human
being. In the case of non-allergic humans, this may go unnoticed,
but in those with varying degrees of sensitivity, exposure to the
dust mite fecal pellets can cause irritation of the respiratory
passages, leading to an itchy stuffy, and/or runny nose, or other
similar allergic responses. In the case of an asthmatic person with
an allergy to dust mites, the reaction to dust mite fecal matter
exposure can be more severe.
[0005] Eradication of these dust mites is virtually impossible in
the home environment, due to the tendency of the human skin to shed
constantly. As a result, those with allergies to the dust mite
fecal matter must typically take efforts to suppress the growth of
mites to the extent possible. Generally, this involves removing
dust mite host environments such as carpets and other home
furnishing items. In addition, doctors treating those individuals
with dust mite fecal matter allergies (hereinafter referred to as
"dust mite allergies") generally recommend encapsulation of pillows
and mattresses, to prevent the cross-transfer of dust mites from
these articles to the allergy sufferer. Furthermore, such
individuals are instructed to wash all non-encapsulated bedding
articles frequently at the hottest temperatures tolerable, to kill
any dust mites which may be living therein.
[0006] Common items for encapsulating the bedding and pillows of an
allergic individual generally utilize a plastic coated material,
plastic film or similar barrier layer to block the transfer of dust
mites. However, such materials can be objectionable to the user, in
that they typically have an undesirable hand, poor drape, tend to
feel thick, and have poor overall aesthetic characteristics. For
that reason, many allergic individuals resist using such barrier
materials.
[0007] Other barrier-type covers available on the market include
ones which are plain woven from polyester and those which are plain
woven from a polyester/cotton blend. These fabrics are typically
very tightly woven, to minimize the size of the openings therein
through which the dust mites can travel. Although providing
barriers for some particles and some superior comfort
characteristics as opposed to their plastic coated or
film-containing counterparts, such fabrics can fail to prevent the
transfer of other common particles, thereby providing ineffective
barrier properties for some purposes. Furthermore, they can have
poor comfort and aesthetic properties as well due to their plastic
feel and thickness.
SUMMARY
[0008] The instant invention overcomes many of the disadvantages of
the prior art barrier fabrics, while providing superior performance
characteristics.
[0009] The fabrics of the instant invention are desirably
lightweight, thin, have good moisture transport properties, and
have superior allergen filtration characteristics. They are
desirably tightly woven in a relatively lightweight construction,
calendered, then desirably face finished, thereby improving the
hand and aesthetic characteristics.
[0010] In one embodiment of the invention, the fabric is woven from
substantially all-polyester. In this embodiment of the invention,
microdenier polyester yarns are desirably used in at least one of
the yarn sets forming the fabric (i.e. the warp or fill direction)
while standard-sized polyester yarns are used in the other
direction. (For purposes of this application, the term microdenier
yarns is intended to describe those yarns made from filaments which
are 1 denier per filament in size or less.) Alternatively,
microdenier yarns can be provided in both of the yarn sets forming
the fabric (i.e. both the warp and fill). In another embodiment of
the invention, the fabric is made from a blend of polyester and
cotton fibers. For example, polyester yarns can be used to form one
of the yarn sets while cotton yarns can be used to form the other
of the yarn sets forming the woven fabric.
[0011] The woven fabrics are then desirably calendered on at least
one side. If desired, the fabrics can be calendered on both sides
by passing the fabric back through the calender a second pass or in
some other manner. However, it has been found that calendering a
single side of the fabric results in a fabric having barrier
properties sufficient to resist the passage of allergens to a
significant extent.
[0012] The fabrics are also desirably face-finished, by sanding,
sueding or the like. In particular, the fabrics are desirably
subjected to a face finishing process which contacts the fabrics at
an angle with one or more abrasive rolls, to abrade the fibers on
the surface of the fabric.
[0013] Fabrics of the instant invention have been found to be
effective barriers from dust mites, as tested both according to
airflow and use simulation tests. In addition, the fabrics have
been found to have dramatically greater effectiveness as a barrier
to cat dander allergen (Fel d1.)
[0014] The fabrics of the instant invention can be used for a
variety of purposes, including but not limited to the production of
protective covers for upholstered and padded articles such as
furniture and bedding items (e.g. mattresses, comforters and
pillows.) For example, the fabric can be used to form a cover for
covering a portion of a mattress (e.g. in the form of a mattress
pad or a regular fitted sheet), a mattress encasing (for
surrounding substantially the entire mattress), a pillow encasing
or the like. When the fabric forms a mattress covering, it is
preferred that the fabric at least form the platform (i.e. the user
contacting surface) of the mattress covering. The items can be
designed to be used alone or in combination with other bedding
articles, such as sheets and the like. In addition, the cover can
form a portion of the pillow covering or the mattress ticking, the
furniture upholstery, or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a flow diagram of a process which can be used to
produce the fabric of the instant invention;
[0016] FIG. 2 is a schematic representation of the process of FIG.
1 in a batch process; and
[0017] FIG. 3 is a schematic representation of a continuous process
which can be used to produce fabrics according to the instant
invention.
DESCRIPTION
[0018] As illustrated in FIGS. 1-3, the fabric 10 is initially
passed through a scouring range 12 where the fabric is scoured and
dried. From the scouring range, the fabric passes through a set of
calender rolls 14 where it is calendered on at least one side. From
the calendar rolls 14, the fabric 10 passes through a face
finishing device 16 such as a sander. The face finishing device
serves to roughen the fibers on the surface of the fabric;
preferably the surface of the fabric opposite that which was
calendered is face finished, although it is noted that both
surfaces of the fabric can be calendered and/or face finished
within the scope of the instant invention. In a preferred form of
the invention, the face finishing device contact the fabric at
angle in the manner described in commonly-assigned U.S. Pat. No.
5,943,745 to Dischler, the disclosure of which is incorporated
herein by reference. It has been found that the use of the face
finishing method described in that reference provides a soft hand
to the fabric without undesirably destroying its strength and
barrier properties. Other types of face finishing processes could
also be used such as that described in commonly-assigned U.S. Pat.
No. 5,815,896 to Dischler, the disclosure of which is incorporated
herein by reference.
[0019] From the face finishing device 16, the fabric desirably
passes through a lint extractor 18 to a collection container 20,
from whence it passes through a heat setting range to a take up
(not shown.)
[0020] The process illustrated in FIGS. 2 and 3 is similar to that
shown in FIG. 1, with FIG. 2 illustrating the fabric being taken up
on a roll 24 after scouring and drying and taken up on another roll
26 after calendering. FIG. 3 illustrates the fabric 10 being
processed continuously from the supply roll 28 to the take up from
the heat setting range 22.
[0021] In one aspect of the invention, the fabric is made from
substantially all-polyester, and has a thickness of less than about
8 mils, and more preferably a thickness of less than about 7 mils.
The fabric is also relatively lightweight, preferably weighing less
than about 3.5 oz/sq. yd and more preferably, less than about 3
oz/sq. yd. The fabric preferably includes about 130 to about 160
ends per inch, and about 50 to about 80 picks per inch. However, it
is noted that other constructions can be used within the scope of
the instant invention. In a preferred form of the invention, the
fabric is a plain woven fabric, having a yarn made from standard
denier polyester filaments in one direction of the weave and a yarn
made from microdenier polyester filaments in the other direction of
the weave; preferably, the microdenier polyester yarn is provided
in the fill direction of the fabric. As the comfort of a fabric is
commonly evidenced by its rate of moisture vapor transport (MVTR),
the fabric desirably has a moisture vapor transmission rate of at
least about 400 g/sq m/24 hrs, and more preferably at least about
425 g/sq m/24 hrs, and even more preferably at least about 430 g/sq
m/24 hrs.
[0022] The fabric also desirably has an air permeability of at
least about 1, and preferably at least about 2 cfm at 125 pa's. The
fabric also desirably allows an airflow of at least about 15 l/min,
and more preferably at least about 20 l/min, and even more
preferably at least about 23 l/min. The fabric also desirably
allows the passage of less than 1 ng of cat dander allergen when
subjected to a Fel d1 cat dander allergen airflow test, more
preferably less than about 0.5 ng of Fel d1 cat dander. In a
particularly preferred form of the invention, the fabric allows the
passage of less than about 0.31 ng of cat dander allergen, as this
is generally considered to be an effective barrier to the passage
of Fel d1 cat dander allergen. The fabric also desirably allows the
passage of less than about 1.3 ng of Der f1 dust mite allergen when
subjected to an airflow test, as this is generally considered to be
the level at which the fabric functions as a dust mite allergen
barrier. The fabric also desirably functions as a dust mite
allergen barrier in use simulation testing, by allowing the passage
of les than about 3.9 ng of Der p1 and Der f1 dust mite
allergen.
[0023] In another embodiment of the invention, the fabric is a
polyester/cotton blend. For example, polyester yarns can be
provided in one of the yarns sets forming the woven fabric while
cotton yarns are provided in the other of the yarn sets. However,
other arrangements of the fibers can be used within the scope of
the instant invention. The polyester/cotton blended fabric of the
invention preferably has a weight which about 4 oz/sq. yd or less,
and more preferably less than or equal to about 3.8 oz/sq. yd. In a
particularly preferred form of the invention, the fabric is about
3.6 oz/sq. yd or less in weight. Although specific types of
polyester and cotton yarns have been described below for purposes
of illustration, it is noted that other sizes and compositions of
yarn can be used within the scope of the invention. Preferably the
fabric has about 130-150 ends per inch and about 50 to about 70
picks per inch. The fabric desirably has an air permeability of at
least about 5 cfm at 125 pa's, and preferably at least about 10 cfm
at 125 pa's. The thickness is preferably less than about 15 mils,
and more preferably less than about 10 mils. In addition, the
fabric desirably has a moisture vapor transmission rate of at least
about 400 g/sq m/24 hrs, more preferably at least about 425 g/sq
m/24 hrs, and even more preferably an MVTR of at least about 430
g/sq m/24 hrs.
[0024] The fabric desirably also allows an airflow of at least
about 25 l/min, more preferably at least about 30 l/min. The fabric
also desirably allows the passage of less than 15 ng of Fel d1 cat
allergen when subjected to a cat dander airflow test, more
preferably less than about 10 ng, and even more preferably less
than about 7.5 ng of Fel d1 cat dander allergen. In addition, the
fabric also is an effective dust mite allergen barrier, in that it
allows the passage of less than 1.3 ng of Der f1 allergen when
subjected to a dust mite allergen airflow test. In addition, the
fabric also allows the passage of less than 3.9 ng of Der p1 and
Der f1 allergen when subjected to a simulated use test.
EXAMPLES
[0025] Commercially available products and those of the instant
invention were tested as follows. The fabrics of the invention
tested were woven as indicated in the tables and calendered on one
side on a BF Perkins woven calender at a speed of 20 (.+-.3) yards
per minute at a set point temperature of 300 degrees Farenheit
(roll actually heated to 325-340 during processing) and at a
pressure of about 1100 (.+-.100) psi. The fabrics were subsequently
face finished on the non-calendered side.
[0026] Fabric Weight Fabric weight was tested in accordance with
ASTM Designation D3776-96.
[0027] Air Permeability
[0028] Air permeability was tested in accordance with ASTM
Designation D 3776-96.
[0029] Thickness
[0030] Thickness was measured according to ASTM Designation D
1777-96.
[0031] Moisture Vapor Transmission
[0032] Moisture vapor transmission (MVTR) was tested in accordance
with ASTM Designation E96-93. It is generally considered that
variations in MVTR must be .+-.25 g/sq m/24 hrs to have effective
significance in comfort differentiation.
[0033] Mite Allergen and Cat Dander Allergen Airflow Test
[0034] An apparatus based on the design reported by Vaughan, J W et
al (JACI 1999; 103:227-231) was used to test allergen barrier
properties of the fabrics. Airflow measurements were calibrated
against a fabric control with a known airflow rate. Five hundred
milligrams of a dust sample with known amounts of the indicated
allergens were pulled across each fabric. A filter cassette mounted
downstream from the fabric collected any allergen that was able to
penetrate the fabric. The filter was extracted in 2.0 mL of 1% BSA
in PBS-Tween 20 overnight. The extract was assayed the following
day with an ELISA for the relevant allergen. The allergens measured
were Mite allergen (Der p1 and Der f1) and Cat allergen (Fel d1).
In the tests, the dust samples included 8982 ng of Fel d1 and 1015
ng of Der f1, respectively. It is generally considered that fabrics
having a Fel d1 measurement of <0.31 would be an effective
barrier to cat dander allergen transfer (smaller particle size) and
fabrics with a Der f1 measurement of <1.3 would be an effective
barrier to dust mite allergen transfer.
[0035] Mite allergens were again tested using the following use
simulation test method:
[0036] Mite Allergen Use Simulation
[0037] A sieved reference dust sample containing a known quantity
of the indicated allergen was loaded into one side of the special
dual chamber along with two steel bearings. The fabric cloth being
investigated was inserted as the barrier between the empty and dust
containing sides of this chamber. Each side of the chamber is a
glass vial (2.1 cm diameter by 4 cm length) with a transfer surface
area between the two vials of 1.13 cm.sup.2. The chamber was
rotated at 25 rotations per minute for 18 hours. The two 1/8" steel
bearings in the allergen vial weighed 132 milligrams each. At the
conclusion of the tumbling period, the empty side was tested for
the presence of allergen by a sensitive enzyme immunoassay with a
limit of detection of 3.9 nanograms of dust mite allergen. When the
results of this use simulation test for a fabric are less than 3.9
nanograms transferred, it can generally be concluded that the
fabric being tested is an effective barrier to dust mite allergen
transfer. The allergen loaded included 0.250 grams of fine dust
containing 6250 nanograms of dust mite allergen.
[0038] Sled Friction
[0039] Sled friction was tested according to ASTM Designation Dl
894-93 in both the warp and fill directions, and both static and
dynamic coefficients of friction (COF) were recorded.
1 Pristine .RTM. 100 Pristine .RTM. Allergy Control Example A-
Allergy Free Prod. 100% Houston, TX Richfield, CT polyester Weight
(oz/sq.yd) 2.83 3.8 2.8 Construction 149 .times. 104 plain 161
.times. 81 plain 143 .times. 67 weave 100% weave 100% plain weave
polyester polyester 100% polyester Warp Yam 1/70/34 textured
1/70/34 textured 1/70/34 round polyester round polyester textured
2.2 DPF 2.2 DPF round polyester 2.2 DPF Fill Yarn 1/70/34 textured
1/175/196 1/140/200 round polyester hollow core textured 2.2 DPF
polyester polyester .7 DPF Air Permeability 12.0 5.9 2.2 (CFM @ 125
pa's) Thickness (mils) 7.50 8.75 7.6 + MVTR 443.0 436.1 431.7 (g/sq
m/24 hrs) Airflow (L/Min) 34.4 24.9 23.9 Cat Allergen Fel d1 3.5
1.3 <.31 (ng) Mite Allergen Der <1.3 <1.3 <1.3 f1 (ng)
Use Simulation <3.9 <3.9 <3.9 Mite Allergen Der p1 and Der
f1 (ng) Sled Friction Warp Static COF 0.681 0.556 0.333 Warp
Dynamic 0.578 0.516 0.274 COF Sled Friction Fill Static COF 0.336
0.669 0.457 Warp Dynamic 0.286 0.578 0.339 COF Pristine .RTM.
Cotton Example B- Allergy Solution 40/60 Chadds Ford, PA
polyester/cotton Weight (oz/sq.yd) 4.0 3.6 Construction 153 .times.
85 plain weave 141 .times. 60 70/30 polyester/cotton plain weave
40/60 polyester/cotton Warp Yarn 1/70/34 textured 1/70/34 round
polyester textured 2.2 DPF round polyester 2.2 DPF Fill Yarn 28/1
Open End spun 20.5/1 100% 50/50 polyester/cotton cotton ring spun
Air Permeability 7.4 11.6 (CFM @ 125 pa's) Thickness (mils) 11.30
9.60 + MVTR (g/sq m/24 hrs) 436.1 433.9 Airflow (L/Min) 18.0* 32.8
Cat Allergen Fel d1 (ng) 22.0* 7.1 Mite Allergen Der f1 (ng) 3*
<1.3 Use Simulation Mite <3.9 <3.9 Allergen Der p1 and Der
f1 (ng) Sled Friction Warp Static COF 0.726 0.431 Warp Dynamic COF
0.586 0.365 Sled Friction Fill Static COF 0.448 0.551 Warp Dynamic
COF 0.469 0.417 *As taken from Pristine Cotton product literature,
which in incorporated herein by reference. Testing conducted by the
University of Virginia Department of Medicine, Asthma, and Allergic
Diseases Center, September 1997. 1.0 g dust load tested including,
respectively, 5.5 mcg/g Der f1 allergen, 3.7 mcg/g of Der p1
allergen, and 510 mcg/g of Fel d1 allergen.
[0040] As noted above, the fabrics of the instant invention have
dramatically improved results as a barrier to cat dander allergen.
In fact, the improved barrier was achieved without a reduction in
comfort, as evidenced by the comparable moisture vapor transmission
rates and airflow properties for the commercial products and those
of the instant invention. Furthermore, the lower warp sled friction
values suggest it may be easier to install such things as mattress
covering made from the fabrics of the invention as compared with
those of the prior art, since the warp direction would generally
correspond to the direction of fabric installation.
* * * * *