U.S. patent application number 12/329894 was filed with the patent office on 2009-04-02 for flame resistant fabric useful as batting in mattresses and upholstery.
This patent application is currently assigned to E. I. DU PONT DE NEMOURS AND COMPANY. Invention is credited to Walter Randall Hall, III, Warren F. Knoff.
Application Number | 20090083910 12/329894 |
Document ID | / |
Family ID | 36581947 |
Filed Date | 2009-04-02 |
United States Patent
Application |
20090083910 |
Kind Code |
A1 |
Knoff; Warren F. ; et
al. |
April 2, 2009 |
FLAME RESISTANT FABRIC USEFUL AS BATTING IN MATTRESSES AND
UPHOLSTERY
Abstract
Flame resistant fabrics useful as battings such as in mattresses
and upholstery contain cellulose fibers (which retain at least 10
percent of their weight when heated in air to 700.degree. C. at a
rate of 20.degree. C. per minute) and animal wool.
Inventors: |
Knoff; Warren F.; (Richmond,
VA) ; Hall, III; Walter Randall; (Richmond,
VA) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY;LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1122B, 4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Assignee: |
E. I. DU PONT DE NEMOURS AND
COMPANY
Wilmington
DE
|
Family ID: |
36581947 |
Appl. No.: |
12/329894 |
Filed: |
December 8, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11047211 |
Jan 31, 2005 |
|
|
|
12329894 |
|
|
|
|
Current U.S.
Class: |
5/698 ;
442/414 |
Current CPC
Class: |
D04H 1/4382 20130101;
A47C 31/001 20130101; D04H 1/4266 20130101; Y10T 442/696 20150401;
Y10T 442/698 20150401; D04H 1/425 20130101; Y10T 442/697
20150401 |
Class at
Publication: |
5/698 ;
442/414 |
International
Class: |
A47C 31/00 20060101
A47C031/00; D04H 13/00 20060101 D04H013/00 |
Claims
1. A flame resistant fabric consisting essentially of: (a)
cellulose fibers containing hydrated silicon dioxide in the form of
silicic acid with aluminum silicate sites which fibers retain at
least 10 percent of the weight when heated in air to 700.degree. C.
at a rate of 20.degree. C. per minute, and (b) animal wool, (c)
binder, wherein (b) is present in a range from 20 to 50% by weight
on a basis of (a) and (b), wherein the fabric is non-woven and
wherein the fabric has a thermal performance temperature in a range
of 125.degree. C. to 500.degree. C.; and wherein, the fabric has a
compression at least 40% measured at 24 hours in accordance with
modified ASTM D6571-01.
2. The fabric of claim 1 with a thermal performance temperature in
a range from 200.degree. C. to 400.degree. C.
3. The fabric of claim 1 with a density in a range from 0.3 to 6.0
pounds per cubic foot (5 to 96 kilogram per cubic meter).
4. The fabric of claim 1 having a basis weight in a range from 3 to
18 ounces per square yard (102 to 610 grams per square meter).
5. The fabric of claim 8 having a basis weight in a range from 4 to
12 ounces per square yard (136 to 407 grams per square meter).
6. The fabric of claim 1 when tested in a mattress according to the
State of California test standard TB603 results in a peak rate of
heat release less than 200 kw during the 30 minute test duration
and a total heat release less than 20 MJ within 10 minutes of test
start.
7. The fabric of claim 1 present as a batting in an article of
manufacture.
8. The fabric of claim 1 present in a mattress.
9. The fabric of claim 1 present in furniture.
Description
RELATED APPLICATION
[0001] The present patent application is a continuation of
application Ser. No. 11/047,211 filed Jan. 31, 2005.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a fire resistant fabric
particularly useful as a fire-blocking batting in a mattress and
furniture.
[0004] 2. Description of the Invention
[0005] The State of California has led the drive to regulate and
reduce the flammability of mattresses and mattress sets in an
attempt to reduce the number of lives lost in household, hotel, and
institutional fires. In particular, the Bureau of Home Furnishings
and Thermal Insulation of the Department of Consumer Affairs of the
State of California issued in July 2004 Technical Bulletin 603
"Requirements and Test Procedure for Resistance of a Residential
Mattress/Box Spring Set to a Large Open-Flame" to quantify the
flammability performance of mattress sets. One measure of screening
fabrics to determine suitability as fire blockers is by use of a
test that measures thermal performance temperature (TPT) of the
fabric, which is a value that is a linear positive function of the
amount of heat that passes through the barrier fabric. Low thermal
performance temperature values mean the fabric is a good insulator
from flame and will help to retard heat transfer to internal areas
of an article such as a mattress.
[0006] There are several ways to incorporate a fire barrier into a
mattress, however, it is preferred in many instances that one of
the existing layers of material be converted to one that can act as
a fire blocking layer. In particular, most mattresses have a high
loft fiber batting, and this batting can provide additional fuel if
made from flammable materials. Replacing this high loft material
with material having a low thermal performance temperature
typically represents an acceptable solution.
[0007] Fire resistant cellulosic fibers can be used effectively to
thermally protect a mattress, however these battings are typically
dense and not soft to the touch.
[0008] PCT Publication WO 03/023108 discloses a nonwoven high loft
flame barrier for use in mattresses and upholstered furniture.
These barriers have very low density, ranging from 5 to 50
kilograms per cubic meter, most preferably 7.5 to 15 kilograms per
cubic meter. The preferred nonwoven high loft flame barrier
comprises a blend of fibers including fibers that are inherently
fire resistant and resistant to shrinkage by direct flame, and
fibers from polymers made with halogenated monomers.
[0009] United States Patent Application Publication US 2004/0060119
discloses a fire barrier fabric having a fire barrier layer and a
thermally insulating layer. The fire barrier layer can be composed
of a blend of aramid and modacrylic fibers and the thermally
insulating layers can be composed derived from fire resistant
viscose and modacrylic fibers.
[0010] These patent applications disclose many types of fabrics but
do not disclose any desired relationship between the thermal
performance temperature of the fabric, density of the fabrics and
the desired softness of the fabric. Therefore, what is needed is a
fabric useful as a batting in mattresses and furniture having a low
thermal performance temperature and a high degree of softness.
SUMMARY OF THE INVENTION
[0011] This invention relates to a fire-resistant fabric useful as
a batting in fire blocking an article such as a mattress or
upholstery and a method of incorporating the fabric into an
article. The fabric comprises: [0012] (a) cellulose containing
fibers which retain at least 10 percent of their weight when heated
in air to 700.degree. C. at a rate of 20.degree. C. per minute, and
[0013] (b) wool, wherein (b) is present in a range of from 15 to
70% by weight on a basis of (a) and (b).
[0014] In a preferred mode the fabric will have a least one of the
following: [0015] (a) a thermal performance temperature in a range
from 125.degree. C. to 500.degree. C. [0016] (b) a compression of
at least 40% measured at 24 hours in accordance with modified ASTM
D 6571-01 [0017] (c) a density in a range from 0.3 to 6.0 pounds
per cubic foot (5 to 96 kilograms per cubic meter) and [0018] (d) a
basis weight of 3 to 18 ounces per square yard (102 to 610 grams
per square meter).
[0019] The present invention also relates to a method of
incorporating the fabric into a final article of manufacture such
as a batting in a mattress or furniture.
BRIEF DESCRIPTION OF THE DRAWING
[0020] FIG. 1 is a graph of thermal performance temperature versus
wool content in a fabric on a basis of cellulose fiber and wool.
All fabrics displayed in this figure have a nominal basis weight of
5.0 ounces per square yard (169.5 grams per square meter) 20% of
which is binder fiber.
DETAILED DESCRIPTION OF THE INVENTION
[0021] A first necessary material in the present invention is a
cellulose fiber which retains at least 10 percent of weight when
heated in air at a rate of 20.degree. C. per minute.
[0022] A preferred cellulose fiber is one formed from viscose fiber
containing hydrated silicon dioxide in the form of a silicic acid
with aluminum silicate sites. Such fibers, and methods for making
such fibers are generally disclosed in U.S. Pat. Nos. 5,417,752 and
PCT Pat. Appl. WO9217629. Viscose fiber containing silicic acid is
sold under the trademark Visil.RTM. by Sateri Oy Company of
Finland.
[0023] A second necessary material in the present invention is
animal wool such as from sheep and goats. Sheep's wool is preferred
due to availability and cost. The amount of wool present in the
fabric will be in a range from 15 to 70% by weight on a basis of
the cellulosic fiber and wool. Preferably, the wool will be in a
range from 20 to 50% on the same basis of cellulosic fiber and
wool.
[0024] Weight as employed herein can also be expressed as basis
weight measured in accordance with ASTM D 6242-98.
[0025] Although both woven and non-woven fabrics are within the
scope of the present invention, a preferred embodiment is a
non-woven fabric that contains a binder. The preferred non-woven
fabrics are high loft battings having thermoplastic binders.
[0026] Preferred binders are activated by the application of heat.
A preferred binder is in the form of a fiber, namely a sheath/core
bicomponent fiber having a core of polyester homopolymer and a
sheath of copolyester such as are commonly available from Unitika
Co., Japan (e.g., sold under the trademark MELTY.RTM.). Other
binders such as thermoplastic powders or fibers commonly used to
bind fibers in webs may be used.
[0027] Preferably the fire-resistant fabric will have a thermal
performance temperature in a range from 125.degree. C. to
500.degree. C. More preferably the range will be from 200 to
400.degree. C.
[0028] As employed herein, thermal performance temperature is
measured using the same instrument employed for NFPA1971 Standard
on Protective Ensemble for Structural Fire Fighting 2000 Edition
Section 6-10. The instrument is operated in a data acquisition
mode. A 2 cal/cm.sup.2/second (8.38 J/cm.sup.2/second) heat flux is
imposed on a fabric for 90 seconds. During this time, the heat
passing through the material is measured using a calorimeter placed
in direct contact with the back face (base layer) of the fabric.
This calorimeter slightly compresses the tested material. The
temperature of the calorimeter thermocouple at the end of the 90
seconds exposure represents the thermal performance temperature.
This temperature is a linear positive function of the amount of
heat transferred through the test specimen and therefore, can be
used to compare the thermal insulating performance of one fabric to
another.
[0029] A further desirable property in a preferred embodiment of
the flame resistant fabric is that it is perceived as soft and
comfortable. One way of describing such comfort is its capability
to compress at a minimum applied load. Although this property may
be measured in different ways, in the present case, compression is
measured in ASTM standard D 6571-01 but modified with use of a 17.6
pound (8 kilogram) weight, a fabric sample size of twelve by twelve
inches (30.4.times.30.4 centimeters).
[0030] The test procedure in the present invention involves
compressing the sample under a 17.6 pound (8 kilogram) weight for 6
hours, removing the load, allowing the sample to recover for a 10
minute period and then measuring the sample thickness. This sample
thickness, designated the initial sample thickness, is the starting
value upon which % compression is finally determined. Immediately
after measuring the initial thickness as described above, the
sample is again compressed under the 17.6 pounds (8 kilogram)
weight for 24 hours after which period the thickness of the loaded
and compressed sample is measured. This thickness value is
designated the final thickness. From these initial and final
thicknesses the % compression is computed from the following
formula:
% compression=[(Initial thickness-final thickness)/initial
thickness].times.100
This test procedure is labeled herein as modified ASTM D6571-01.
The test procedure may be described as performing a 6 hour
compression period and a 10 minute recovery period to obtain a
starting conditioned sample upon which a then a 24 hour period is
required to obtain a final compressed thickness from which the %
compression is computed.
[0031] The starting fabric sample is considered to relate to fabric
such as a batting which is typically stored in roll form prior to
actual use in the final material such as a portion of a mattress,
upholstery, sleeping bag, comforter, etc. Illustratively, the
fabric as a batting in a mattress when tested according to the
State of California test standard TB603 can result in a peak rate
of heat release less than 200 kW during the 30 minutes test
duration and a total heat release less than 25 MJ within 10 minutes
of test start.
[0032] An important property which can be obtained with fabrics of
the present invention is an ability of the fabric to be evaluated
as soft. It is understood that softness is a subjective term and it
will vary from person to person. Also, there is no sharp line
between a fabric which is perceived as soft as opposed to not being
soft. Also, a fabric perceived as soft such as in use as upholstery
may not be perceived as soft as part of a mattress construction.
However, for purposes of the present invention, a soft fabric has a
compression of at least 40% when measured in accordance with
modified ASTM D6571-01 as previously described.
[0033] If higher thermal performance is required, the total basis
weight of the cellulose and wool batting can be increased. If
higher thermal performance combined with increased structural
integrity during the flame resistant test is required, it may be
desirable to add a further material to the cellulose fiber and
wool. Illustratively, these materials are heat resistant and
include aramid, especially para-aramid, polybenzazole
polybenzimidazole and polyimide. Generally, the material will be
present as a fiber.
[0034] Preferably, the fire resistant fabric will have a density in
a range from 0.3 to 6.0 pounds per cubic foot (5 to 96 kilograms
per cubic meter) and more preferably a density in a range from 0.3
to 4.3 pounds per cubic foot 5 to 70 kilograms per cubic
meter).
[0035] Another property of the fire resistant fabric that
influences the thermal performance temperature is the weight per
unit area, or basis weight. A suitable basis weight is in a range
of 3 to 18 ounces per square yard (102 to 610 grams per square
meter and more preferably 4 to 12 ounces per square yard (136 to
407 grams per square meter). Basis weight can be measured in
accordance with ASTM D6242-98.
[0036] If the flame resistant fabric is employed as a batting and
additional durability or strength is desired, such fabric can be
contacted and joined with another fabric such a woven or nonwoven
scrim fabric such as by sewing or use of an adhesive.
[0037] In the following examples all parts and percentages are by
weight and degrees in centigrade unless otherwise indicated. The
test measurements were as previously described. In addition,
compression also was measured at different time periods as
noted.
[0038] In the following examples the following materials were
employed:
TABLE-US-00001 binder: a copolymer polyester sheath/polyester core
fiber having a melting temperature of about 120.degree. C. and an
individual filament denier of 4 dpf (4.4 dtex) and average cut
length of 2 inches (51 mm) supplied by Samyang Corporation. fire
resistant type 33 AP Visil .RTM. cellulose fiber having cellulose:
having an individual filament denier of 3.5 dpf (3.9 dtex) and
average cut length of 2 inches (51 mm) available from Sateri Oy.
wool: sheep's wool of 54S numerical count grade scoured and combed
and average cut length of 2 inches (51 mm). aramid:
poly(paraphenylene terephthalamide) supplied as Kevlar .RTM. Type
970 by E. I. du Pont de Nemours and Company having an individual
filament denier of 2.25 dpf (2.50 dtex) average cut length of 2
inches (51 mm).
[0039] The fibers used in this invention retain a portion of their
fiber weight when heated to high temperature at a specific heating
rate. This fiber weight was measured using a Model 2950
Thermogravimetric Analyzer (TGA) available from TA Instruments (a
division of Waters Corporation) of Newark, Del. The TGA gives a
scan of sample weight loss versus increasing temperature. Using the
TA Universal Analysis program, percent weight loss can be measured
at any recorded temperature. The program profile consists of
equilibrating the sample to 50 degrees C., placing the sample in a
500 microliter ceramic cup (PN 952018.910) sample container and
ramping the temperature of the air, as measured by a thermocouple
placed directly above the lip of the sample container, at 20
degrees C. per minute from 50 to 1000 degrees C., using air
supplied at 10 ml/minute. The testing procedure is as follows. The
TGA was programmed using the TGA screen on the TA Systems 2900
Controller. The sample ID was entered and the planned temperature
ramp program of 20 degrees per minute selected. The empty sample
cup was tared using the tare function of the instrument. The fiber
sample was cut into approximately 1/16'' (0.16 cm) lengths and the
sample pan was loosely filled with the sample. The sample weight
should be in the range of 120 to 60 mg. The TGA has a balance
therefore the exact weight does not have to be determined
beforehand. None of the sample should be outside the pan. The
filled sample pan was loaded onto the balance wire making sure the
thermocouple is close to the top edge of the pan but not touching
it. The furnace is raised over the pan and the TGA is started. Once
the program is complete, the TGA will automatically lower the
furnace, remove the sample pan, and go into a cool down mode. The
TA Systems 2900 Universal Analysis program is then used to analyze
and produce the TGA scan for percent weight loss over the range of
temperatures.
Part 1
[0040] Fabrics in the form of battings as set forth in Table 1 were
blended using conventional carding/garnet machines and crosslappers
that opened and blended the fibers. The fabrics were heat set using
a through-air oven and then cooled at room temperature.
[0041] For each of fabric samples A through E and for sample F,
which had no fabric sample mounted in the instrument, 10 different
measurements were recorded. An average basis weight and an average
thermal performance temperature was calculated. Additionally a 95%
confidence limit was also calculated both for the basis weight and
thermal performance temperature. The values are set forth in Table
1.
TABLE-US-00002 TABLE 1 SAMPLE A B C D E F % Wool 0 25 38 50 100 0
Nominal Basis 5 5 5 5 5 0.0 Weight (170) (170) (170) (170) (170)
(0.0) Average Basis 4.8 5.4 5.1 4.8 6.2 0.0 Weight (163.7) (183.1)
(172.9) (162.7) (210.2) (0.0) 95% Confidence 0.2 0.2 0.3 0.3 0.2
0.0 Limit of Average (6.8) (6.8) (10.2) (10.2) (6.8) Basis Weight
Density 17.6 18.1 18.3 21.9 19.4 0 (0.018) (0.018) (0.018) (0.022)
(0.019) (0.0) Average of 315 316 285 324 730 678 Thermal
Performance Temperature 95% Confidence 15 16 12 13 32 11 Limit of
Average Thermal Performance Temperature (1) All weight in ounces
per square yard (grams per square meter). (2) % wool on basis of
wool and cellulose only. (3) All samples (except the sample labeled
F with no fabric) include binder fiber at 20% of the total sample
basis weight. (4) Density in ounces per cubic foot (grams per cubic
centimeter) measured by ASTM D6242-98. (5) Temperature in .degree.
C.
[0042] From Table 1, the following observations were made: [0043]
(a) For Sample F, i.e. no fabric was present for thermal
performance temperature measurement. The temperature was lower
compared to Sample E with no cellulose (i.e., only wool and binder)
[0044] (b) Samples A through E were compared against expected
thermal performance temperatures calculated from a "rule of mixing"
which is considered to predict that the thermal performance
temperature of a wool/cellulose fabric should equal the weight
percent of wool times the thermal performance temperature of wool
plus the weight percent of cellulose times the thermal performance
temperature of cellulose.
[0045] FIG. 1 shows an unexpected improvement in thermal
performance temperature from the "rule of mixing" as the wool
percent is increased on a basis of the wool and cellulose present
in the fabric. The fabric samples had a nominal basis weight of 5
ounces per square yard (169 grams per square meter) and 20% of the
fabric weight was binder.
Part II
[0046] Table 2 contains % compression data obtained in accordance
with modified ASTM D 6571-01 described above
[0047] Two of the samples did not contain aramid each of which are
identified at the end of Table 2. Samples A and D were identical to
Samples A and D of Part I. Thickness values are in inches
(centimeters)
TABLE-US-00003 TABLE 2 Initial Thickness Final Thickness Sample A
THICKNESS 1.44 (3.66) 0.94 (2.39) % COMPRESSION 0 34.7% Sample D
THICKNESS 1.38 (3.51) 0.69 (1.75) % COMPRESSION 0 50.0% Sample G
THICKNESS 3.06 (7.77) 1.94 (4.93) % COMPRESSION 0 36.6% Sample H
THICKNESS 2.50 (6.35) 1.25 (3.18) % COMPRESSION 0 50.0% Sample A
was 80% cellulose and 20% binder (i.e. 0% wool). Sample D was 40%
wool, 40% cellulose and 20% binder (i.e. 50% wool on basis of wool
and cellulose) Sample G was 40% cellulose, 20% binder and 40%
aramid (i.e. 0% wool) Sample H was 29% wool, 29% cellulose, 13%
binder and 29% aramid (i.e. 50% wool on basis of wool and
cellulose)
[0048] Sample A (which did not contain wool or aramid) and Sample H
(which did not contain wool but contained aramid) did not reach a
minimum compression of at least 40%
[0049] Sample D (which contained wool but did not contain aramid)
and Sample H (which contained both wool and aramid) had a
compression of 50%.
* * * * *