U.S. patent application number 10/807068 was filed with the patent office on 2005-09-29 for layered high loft flame resistant batting, articles containing said batting, and process for making same.
Invention is credited to Bascom, Laurence N., Lim, Hyun Sung.
Application Number | 20050210584 10/807068 |
Document ID | / |
Family ID | 34964264 |
Filed Date | 2005-09-29 |
United States Patent
Application |
20050210584 |
Kind Code |
A1 |
Lim, Hyun Sung ; et
al. |
September 29, 2005 |
Layered high loft flame resistant batting, articles containing said
batting, and process for making same
Abstract
This invention relates to a high loft flame resistant batting,
and an article such as a mattress containing such batting; the
batting comprising a base layer and a resilient layer, the base
layer comprising 10 to 30 parts by weight heat resistant fibers, 35
to 55 parts by weight of a cellulose fiber that retains at least 10
percent of its fiber weight when heated in air to 700 C at a rate
of 20 degrees C. per minute, and 15 to 25 parts by weight binder
material; the resilient layer comprising 0 to 50 parts by weight
modacrylic fibers, 50 to 85 parts by weight polyester fiber, and 15
to 25 parts by weight binder material. The base layer comprises 20
to 70 parts by weight and the resilient layer comprises 80 to 30
parts by weight of the batting, based on the total weight of those
two layers, and the batting has a total thickness of 1.25
centimeters (0.5 inches) or greater.
Inventors: |
Lim, Hyun Sung; (Midlothian,
VA) ; Bascom, Laurence N.; (Amelia, VA) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY
LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1128
4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
34964264 |
Appl. No.: |
10/807068 |
Filed: |
March 23, 2004 |
Current U.S.
Class: |
5/483 ; 5/698;
5/952 |
Current CPC
Class: |
D04H 1/43832 20200501;
D04H 1/5412 20200501; D04H 1/559 20130101; D04H 1/43835 20200501;
D04H 1/02 20130101; D04H 1/4374 20130101; D04H 1/5414 20200501;
D04H 1/4342 20130101; D04H 1/5418 20200501; D04H 1/43 20130101;
D04H 1/4258 20130101; D04H 1/43828 20200501; A47C 31/001
20130101 |
Class at
Publication: |
005/483 ;
005/952; 005/698 |
International
Class: |
A47C 027/00 |
Claims
1. A high loft flame resistant batting, comprising: (a) a base
layer comprising (i) 10 to 30 parts by weight heat resistant
fibers, (ii) 35 to 55 parts by weight of a cellulose fiber that
retains at least 10 percent of its fiber weight when heated in air
to 700.degree. C. at a rate of 20 degrees C. per minute, and (iii)
15 to 25 parts by weight binder material; (b) a resilient layer
comprising (i) 0 to 50 parts by weight modacrylic fibers, (ii) 50
to 85 parts by weight polyester fiber, and (iii) 15 to 25 parts by
weight binder material; the base layer comprising 20 to 70 parts by
weight and the resilient layer comprising 80 to 30 parts by weight
of the batting, based on the total weight of those two layers, the
batting having a total thickness of 1.25 centimeters (0-5 inches)
or greater.
2. The high loft flame resistant batting of claim 1 wherein the
heat resistant fiber is an organic fiber that retains 90 percent of
its fiber weight when heated in air to 500.degree. C. at a rate of
20 degrees C. per minute.
3. The high loft flame resistant batting of claim 2 wherein the
heat-resistant fiber comprises a para-aramid, polybenzazole,
polybenzimidazole, or polyimide polymer.
4. The high loft flame resistant batting of claim 3 wherein the
para-aramid is poly(paraphenylene terephthalamide).
5. The high loft flame resistant batting of claim 1 wherein the
cellulose fiber is a viscose fiber containing silicic acid.
6. The high loft flame resistant batting of claim 1 having a total
composite density of 0.33 to 2.0 pounds per cubic foot.
7. The high loft flame resistant batting of claim 1 having a basis
weight of 8 to 12 ounces per square yard.
8. The high loft flame resistant batting of claim 1 wherein
modacrylic fibers are present in the resilient layer in the amount
of 20 to 50 parts by weight.
9. The high loft flame resistant batting of claim 1 wherein
polyester fibers are present in the resilient layer in the amount
of 30 to 60 parts by weight.
10. The high loft flame resistant batting of claim 1 wherein heat
resistant fibers are present in the base layer in the amount of 20
to 30 parts by weight.
11. The high loft flame resistant batting of claim 1 wherein
cellulose fibers are present in the base layer in the amount of 40
to 50 parts by weight.
12. The high loft flame resistant batting of claim 1 wherein the
base layer further contains polyester fibers in the amount of up to
15 parts by weight.
13. The high loft flame resistant batting of claim 1 wherein the
base layer further contains modacrylic fibers in the amount of up
to 5 parts by weight.
14. The high loft flame resistant batting of claim 1 wherein the
binder material is a binder fiber.
15. An article comprising the high loft flame resistant batting of
claim 1 as a fire blocking layer.
16. A mattress comprising the high loft flame resistant batting of
claim 1 as a fire blocking layer.
17. A process for making a high loft flame resistant batting,
comprising the steps of: a) forming a base layer fiber mixture
comprising (i) 10 to 30 parts by weight heat resistant fibers, (ii)
35 to 55 parts by weight of a cellulose fiber that retains at least
10 percent of its fiber weight when heated in air to 700 C at a
rate of 20 degrees C. per minute, and (iii) 15 to 25 parts by
weight binder fibers; b) forming a resilient layer fiber mixture
comprising (i) 0 to 50 parts by weight modacrylic fibers, (ii) 50
to 85 parts by weight polyester fiber, and (iii) 15 to 25 parts by
weight binder fibers; c) forming a layered batt having a total
thickness of at least 1.25 centimeters (0.5 inches), wherein one
layer contains the base layer fiber mixture and another layer
contains the resilient layer fiber mixture; and d) heating the
layered batt to activate the binder fibers and form a high loft
batting.
18. The process of claim 17 wherein the base layer fiber mixture is
present in the layered batt in an amount of 20 to 70 parts by
weight of the total weight of the high loft batting.
19. The process of claim 17 wherein the resilient layer fiber
mixture is present in the layered batt in an amount of 80 to 30
parts by weight of the total weight of the high loft batting.
20. The process of claim 17 wherein the layered batt is formed by
first forming separate webs of the base layer fiber mixture and the
resilient layer fiber mixture and then layering the webs on top of
each other.
21. The process of claim 17 comprising the additional step: a)
recycling a portion of the high loft batting wherein the fibers of
the recycled portion become part of the base layer fiber
mixture.
22. The process of claim 21 wherein the recycled fibers comprise no
more than 25 parts by weight of the base layer fiber mixture.
23. A fire blocking quilt comprising outer fabric ticking or cover
fabric layer, one or more layers of a layered high loft flame
resistant batting, and optionally a stitch-backing layer; wherein
the high loft batting comprises a base layer comprising (i) 10 to
30 parts by weight heat resistant fibers, (ii) 35 to 55 parts by
weight of a cellulose fiber that retains at least 10 percent of its
fiber weight when heated in air to 700.degree. C. at a rate of 20
degrees C. per minute, and (iii) 15 to 25 parts by weight binder
material; and a resilient layer comprising (i) 0 to 50 parts by
weight modacrylic fibers, (ii) 50 to 85 parts by weight polyester
fiber, and (iii) 15 to 25 parts by weight binder material; the base
layer comprising 20 to 70 parts by weight and the resilient layer
comprising 80 to 30 parts by weight of the batting based on the
total weight of those two layers, the batting having a total
thickness of at least 1.25 centimeters (0.5 inches).
24. A method of fire blocking an article, comprising the steps of
a) combining a layer of a fabric ticking or upholstery, and a high
loft batting, and optionally a stitch backing layer, the high loft
batting comprising a base layer comprising (i) 10 to 30 parts by
weight heat resistant fibers, (ii) 35 to 55 parts by weight of a
cellulose fiber that retains at least 10 percent of its fiber
weight when heated in air to 700.degree. C. at a rate of 20 degrees
C. per minute, and (iii) 15 to 25 parts by weight binder material;
and a resilient layer comprising (1) 0 to 50 parts by weight
modacrylic fibers, (ii) 50 to 85 parts by weight polyester fiber,
and (iii) 15 to 25 parts by weight binder material; the base layer
comprising 20 to 70 parts by weight and the resilient layer
comprising 80 to 30 parts by weight of the batting, based on the
total weight of those two layers, the batting having a total
thickness of at least 1.25 centimeters (0.5 inches), b) sewing the
layers together to form a fire blocked quilt or upholstery fabric,
and c) incorporating the fire blocked quilt or upholstery fabric
into the article.
25. The process of claim 23 wherein the article is a mattress.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a layered high loft flame
resistant batting for use in fire-blocking an article such as a
mattress and processes for making the batting and methods of
fire-blocking articles. When burned mattress sets utilizing the
high loft flame resistant batting of this invention have a peak
heat release rate of less than 200 kilowatts within 30 minutes and
a total heat release of less than 25 megajoules within 10 minutes
when tested according to Technical Bulletin 603 of the State of
California, as revised July 2003.
[0003] 2. Description of Related Art
[0004] 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 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.
[0005] Mattresses normally contain a mattress core covered by
cushioning material or batting that is in turn covered with an
outer fabric ticking. Most cushioning material or batting is made
from foam or fiber materials that will burn when exposed to an open
flame. One useful method of fire blocking foam cushions,
particularly airplane seats, is disclosed in U.S. Pat. No.
4,750,443 to Blaustein, et al., wherein three to seven layers of
flame resistant fabrics are used underneath the covering fabric of
the seat to encase the foam. To the degree required per the
aircraft seat flammability test method, these fire-blocked cushions
withstand a flame jet impinging on the cushion and prevent the
entire cushion from being engulfed by the flame or continuing to
burn after the flame jet is removed. When applied to mattresses,
the use of multiple fire blocking layers underneath the ticking can
add stiffness or restrain the give of the mattress core, affecting
overall comfort. Even single layers of fire blocking fabrics can
restrain batting materials and affect the cushioning of mattresses.
Therefore, what is desired is a solution that does not require
incorporating an additional fire blocking layer. In particular,
what is desired is a batting material that can also function as a
fire blocker for the mattress or upholstered article.
[0006] Fibers such as para-aramid fibers are very useful in flame
retardant fabrics however these fibers have a natural gold color
that is present in fabrics made from substantial amounts of those
fibers. It is undesirable for the natural gold color of the
para-aramid fabric to show through the outer ticking of mattresses,
which are normally of a white or light or off-white color, or to
show through the outer upholstery covering fabric of furniture.
Therefore, what is needed is a high loft flame resistant batting
that incorporates a heat resistant fiber wherein the color of that
heat resistant fiber is masked by other fibers in the high loft
flame resistant batting, while still meeting important flame
resistant requirements.
[0007] 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 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.
[0008] U.S. Pat. Nos. 6,132,476; 6,547,835, and 5,609,950 disclose
fabric blends of inherently flame resistant fibers and cellulosic
fibers having increased flame resistance; the fabric can contain an
additional fire retardant that is added, for example, as an
additive in a dyeing step. Because of the low content of inorganic
material the flame resistant cellulose fiber disclosed in these
references does not retain an adequate percentage of its weight
when exposed to high temperatures.
[0009] U.S. Pat. Nos. 6,579,396 and 6,383,623 disclose a high
temperature insulating material having a density of from 0.1 to 3.0
pounds/cubic foot made from non-thermoplastic fibers and
thermoplastic binder materials. The binder materials completely
melt, and the liquefied thermoplastic material, presumably under
the influence of surface tension, collects at the points the
non-thermoplastic fibers come together, forming nodes when cooled,
in contrast to sheath-core binder fibers that can bind a number of
fibers to the binder fiber along its length and that retains a core
of thermoplastic material after heating.
[0010] U.S. Pat. No. 4,199,642 discloses an intimate blend of 80 to
98 percent polyester fiberfill and 2 to 20 percent synthetic
organic filamentary material. The organic filamentary material can
be poly(p-phenylene terephthalamide) or flame-retardant rayon.
[0011] U.S. Pat. No. 5,578,368 discloses a fire-resistant material
comprising a fiberfill batt and at least one fire-resistant layer
of aramid fibers.
SUMMARY OF THE INVENTION
[0012] This invention relates to a high loft flame resistant
batting and an article such as a mattress containing such batting;
the batting comprising a base layer and a resilient layer, the base
layer comprising 10 to 30 parts by weight heat resistant fibers, 35
to 55 parts by weight of a cellulose fiber that retains at least 10
percent of its fiber weight when heated in air to 700 C at a rate
of 20 degrees C. per minute, and 15 to 25 parts by weight binder
material; the resilient layer comprising 0 to 50 parts by weight
modacrylic fibers, 50 to 85 parts by weight polyester fiber, and 15
to 25 parts by weight binder material. The base layer comprises 20
to 70 parts by weight and the resilient layer comprises 80 to 30
parts by weight of the batting, based on the total weight of those
two layers, and the batting has a total thickness of 1.25
centimeters (0.5 inches) or greater.
[0013] This invention also relates to a process for making a high
loft flame resistant batting, comprising the steps of:
[0014] a) forming a base layer fiber mixture comprising 10 to 30
parts by weight heat resistant fibers, 35 to 55 parts by weight of
a cellulose fiber that retains at least 10 percent of its fiber
weight when heated in air to 700.degree. C. at a rate of 20 degrees
C. per minute, and 15 to 25 parts by weight binder fibers;
[0015] b) forming a resilient layer fiber mixture comprising 0 to
50 parts by weight modacrylic fibers, 50 to 85 parts by weight
polyester fiber, and 15 to 25 parts by weight binder fibers;
[0016] c) forming a layered batt having a total thickness of at
least 1.25 centimeters (0.5 inches) wherein one layer contains the
base layer fiber mixture and another layer contains the resilient
layer fiber mixture; and
[0017] d) heating the layered batt to activate the binder fibers
and form a high loft batting.
[0018] Optionally, a portion of the high loft batting can be
recycled into the base layer fiber mixture.
[0019] This invention further relates to a fire blocking quilt
incorporating a layered high loft flame resistant batting and a
method of fire blocking an article comprising the steps of:
[0020] a) combining a layer of a fabric ticking or upholstery, a
high loft batting, and optionally a stitch backing layer, the high
loft batting comprising
[0021] a base layer comprising 10 to 30 parts by weight heat
resistant fibers,
[0022] 35 to 55 parts by weight of a cellulose fiber that retains
at least 10 percent of its fiber weight when heated in air to
700.degree. C. at a rate of 20 degrees C. per minute, and 15 to 25
parts by weight binder material; and
[0023] a resilient layer comprising 0 to 50 parts by weight
modacrylic fibers,
[0024] 50 to 85 parts by weight polyester fiber, and 15 to 25 parts
by weight binder material;
[0025] the base layer comprising 20 to 70 parts by weight and the
resilient layer comprising 80 to 30 parts by weight of the batting,
based on the total weight of those two layers, the batting having a
total thickness of at least 1.25 centimeters (0.5 inches),
[0026] b) sewing the layers together to form a fire blocked quilt
or upholstery fabric, and
[0027] c) incorporating the fire blocked quilt or upholstery fabric
into the article.
DETAILS OF THE INVENTION
[0028] This invention relates to a layered high loft flame
resistant batting, and an article such as a mattress containing
such batting. The batting comprises a base layer and a resilient
layer that work together to form a fire blocking material. The base
layer comprises 10 to 30 parts by weight heat resistant fibers, 35
to 55 parts by weight of a cellulose fiber that retains at least 10
percent of its fiber weight when heated in air to 700.degree. C. at
a rate of 20 degrees C. per minute, and 15 to 25 parts by weight
binder material; the resilient layer comprises 0 to 50 parts by
weight modacrylic fibers, 50 to 85 parts by weight polyester fiber,
and 15 to 25 parts by weight binder material. In the layered high
loft batting, the base layer is present in an amount of 20 to 70
parts by weight and the resilient layer is present in an amount of
80 to 30 parts by weight, based on the total weight of the base and
resilient layers.
[0029] The high loft layered battings of this invention have a
total thickness of 1.25 centimeters (0.5 inches) or greater. While
there is no real limitation on how thick the batting can be, for
many typical applications, the thickness of the high loft batting
need not be higher than 7.6 cm (3 in), and for many mattress
applications less than 5 cm (2 in) is very useful. The layered
battings of this invention also have a preferred basis weight in
the range of 8 to 12 ounces per square yard. The battings also
have, based on the total weight and thickness of the combined
layers, a preferred composite density of 5.3 to 32 kilograms per
cubic meter (0.33 to 2.0 pounds per cubic foot). Denser battings
generally do not have the resiliency desired for use as cushioning
in mattresses and other articles. Battings that are thinner or less
dense than the desired ranges are not thought to provide the amount
of cushioning desired.
[0030] The base layer of the layered high loft batting contains 10
to 30 parts by weight heat resistant fibers, 35 to 55 parts by
weight of a cellulose fiber that retains at least 10 percent of its
fiber weight when heated in air to 700.degree. C. at a rate of 20
degrees C. per minute, and 15 to 25 parts by weight binder
material. Preferably, the heat resistant fibers are present in the
amount of 20 to 30 parts by weight, the cellulose fibers are
present in the amount of 40 to 50 parts by weight. The base layer
provides a dense structure that forms a char and maintains
integrity in flame.
[0031] By "heat resistant fiber" it is meant that the fiber
preferably retains 90 percent of its fiber weight when heated in
air to 500.degree. C. at a rate of 20 degrees C. per minute. Such
fiber is normally flame resistant, meaning the fiber or a fabric
made from the fiber has a Limiting Oxygen Index (LOI) such that the
fiber or fabric will not support a flame in air, the preferred LOI
range being about 26 and higher. The preferred fibers do not
excessively shrink when exposed to a flame, that is, the length of
the fiber will not significantly shorten when exposed to flame.
Fabrics containing an organic fiber that retains 90 percent of its
fiber weight when heated in air to 500.degree. C. at a rate of 20
degrees C. per minute tend to have limited amount of cracks and
openings when burned by an impinging flame, which is important to
the fabric's performance as a fire blocker.
[0032] Heat resistant and stable fibers useful in the nonwoven
fire-blocking fabric of this invention include fiber made from
para-aramid, polybenzazole, polybenzimidazole, and polyimide
polymer. The preferred heat resistant fiber is made from aramid
polymer, especially para-aramid polymer.
[0033] As used herein, "aramid" is meant a polyamide wherein at
least 85% of the amide (--CONH--) linkages are attached directly to
two aromatic rings. "Para-aramid" means the two rings or radicals
are para oriented with respect to each other along the molecular
chain. Additives can be used with the aramid. In fact, it has been
found that up to as much as 10 percent, by weight, of other
polymeric material can be blended with the aramid or that
copolymers can be used having as much as 10 percent of other
diamine substituted for the diamine of the aramid or as much as 10
percent of other diacid chloride substituted for the diacid
chloride of the aramid. In the practice of this invention, the
preferred para-aramid is poly(paraphenylene terephthalamide).
Methods for making para-aramid fibers useful in this invention are
generally disclosed in, for example, U.S. Pat. Nos. 3,869,430,
3,869,429, and 3,767,756. Such aromatic polyamide organic fibers
and various forms of these fibers are available from DuPont
Company, Wilmington, Del. under the trademark Kevlar.RTM.
fibers.
[0034] Commercially available polybenzazole fibers useful in this
invention include Zylon.RTM. PBO-AS
(Poly(p-phenylene-2,6-benzobisoxazole- ) fiber, Zylon.RTM. PBO-HM
(Poly(p-phenylene-2,6-benzobisoxazole)) fiber, available from
Toyobo, Japan. Commercially available polybenzimidazole fibers
useful in this invention include PBI.RTM. fiber available from
Celanese Acetate LLC. Commercially available polyimide fibers
useful in this invention include P-84.RTM. fiber available from
LaPlace Chemical.
[0035] The base layer of the layered high loft batting also
contains 35 to 55 parts by weight of a cellulose fiber that retains
at least 10 percent of its fiber weight when heated in air to
700.degree. C. at a rate of 20 degrees C. per minute. These fibers
are said to be char forming. The cellulose fibers used in the
composite of this invention are preferably regenerated cellulose
fibers have 10 percent inorganic compounds incorporated into the
fibers. Such fibers, and methods for making such fibers, are
generally disclosed in U.S. Pat. No. 3,565,749 and British Patent
No. 1,064,271. A preferred char-forming regenerated cellulose fiber
for this invention is a viscose fiber containing silicon dioxide in
the form of a polysilicic acid with aluminum silicate sites. Such
fibers, and methods for making such fibers are generally disclosed
in U.S. Pat. No. 5,417,752 and PCT Pat. Appl. WO 9217629. Viscose
fiber containing silicic acid and having approximately 31 (+/-3)
percent inorganic material is sold under the trademark Visil.RTM.
by Sateri Oy Company of Finland.
[0036] The base layer of the layered high loft batting also
contains 15 to 25 parts by weight binder material. The preferred
binder material is a binder fiber that is activated by the
application of heat. Such binder fibers are typically made from a
thermoplastic material that flows at a temperature that is lower
(i.e., has a softening point lower) than the softening point of any
of the other staple fibers in the fiber blend. Sheath/core
bicomponent fibers are preferred as binder fibers, especially
bicomponent binder fibers having a core of polyester homopolymer
and a sheath of copolyester that is a binder material, such as are
commonly available from Unitika Co., Japan (e.g., sold under the
trademark MELTY.RTM.). Useful types of binder fibers can include
those made from polypropylene, polyethylene, or polyester polymers
or copolymers, the fibers containing only that polymer or
copolymer; or as a bicomponent fiber in side-by-side or sheath/core
configuration.
[0037] The resilient layer of the layered high loft batting
contains 0 to 50 parts by weight modacrylic fibers, 50 to 85 parts
by weight polyester fiber, and 15 to 25 parts by weight binder
material. The resilient layer preferably functions as the outer
layer of the layered high loft batting, providing a resilient
structure that sacrificially melts in flame and optionally,
off-gasses to suppress flames. The resilient layer is typically
white or light in color and also preferably shields any coloring of
the base layer.
[0038] The resilient layer contains 50 to 85 parts by weight
polyester fiber to provide resilience to layered batting. If more
than 85 parts by weight polyester fibers are used, it is believed
the batting becomes too flammable to be used in fire blockers.
Polyester fibers are well known in the art and can be obtained from
many sources. The preferred polyester fiber is made from
poly(ethylene terephthalate) (PET)polymer. Other polyesters,
however, may be used, such as homopolymers, copolymers,
terpolymers, and blends etc., of polyester polymers and monomers of
poly(propylene terephthalate, poly(butylenes terephthalate),
poly(1,4-cyclohexylene-dimethylene terephthalate) and copolymers
and mixtures thereof. One type of PET fiber useful in this
invention is commercially available from Invista, Inc. of
Wilmington, Del. under the trademark DACRON.RTM. Type 808 single
hole hollow fiber having a linear density of 7.2 dtex/filament (6.5
denier/filament) having a cut length of 3.8 cm (1.5 in).
[0039] The resilient layer also contains 15 to 25 parts by weight
binder material. As in the base layer, the preferred binder
material is a binder fiber that is activated by the application of
heat. Generally the same binder can be used for both the resilient
and base layers, however, this is not a requirement.
[0040] The resilient layer optionally also contains 0 to 50 parts
by weight modacrylic fibers. Modacrylic fiber is useful in this
outer layer of the batting because this fiber releases
flame-suppressing halogen-containing gases when burned. By
modacrylic fiber it is meant acrylic synthetic fiber made from a
polymer comprising acrylonitrile. Preferably the polymer is a
copolymer comprising 30 to 70 weight percent of an acrylonitrile
and 70 to 30 weight percent of a halogen-containing vinyl monomer.
The halogen-containing vinyl monomer is at least one monomer
selected, for example, from vinyl chloride, vinylidene chloride,
vinyl bromide, vinylidene bromide, etc. Examples of copolymerizable
vinyl monomers are acrylic acid, methacrylic acid, salts or esters
of such acids, acrylamide, methylacrylamide, vinyl acetate,
etc.
[0041] The preferred modacrylic fibers used in this invention are
copolymers of acrylonitrile combined with vinylidene chloride, the
copolymer having in addition an antimony oxide or antimony oxides
for improved fire retardancy. Such useful modacrylic fibers
include, but are not limited to fibers disclosed in U.S. Pat. No.
3,193,602 having 2 weight percent antimony trioxide, fibers
disclosed in U.S. Pat. No. 3,748,302 made with various antimony
oxides that are present in an amount of at least 2 weight percent
and preferably not greater than 8 weight percent, and fibers
disclosed in U.S. Pat. Nos. 5,208,105 and 5,506,042 having 8 to 40
weight percent of an antimony compound. The preferred modacrylic
fiber is commercially available Protex C from Kaneka Corporation,
Japan, which is said to contain 10 to 15 weight antimony oxides,
although fibers having less antimony oxide, in the range of 6
weight percent or less, can also be used.
[0042] In the layered high loft batting, the base layer is present
in an amount of 20 to 70 parts by weight and the resilient layer is
present in an amount of 80 to 30 parts by weight, based on the
total weight of the base and resilient layers. Preferably the base
layer is present in an amount of 40 to 55 parts by weight and the
resilient layer is present in an amount of 60 to 45 parts by
weight.
[0043] This invention also relates to a process for making a high
loft flame resistant batting, comprising the steps of:
[0044] a) forming a base layer fiber mixture comprising 10 to 30
parts by weight heat resistant fibers, 35 to 55 parts by weight of
a cellulose fiber that retains at least 10 percent of its fiber
weight when heated in air to 700.degree. C. at a rate of 20 degrees
C. per minute, and 15 to 25 parts by weight binder fibers;
[0045] b) forming a resilient layer fiber mixture comprising 0 to
50 parts by weight modacrylic fibers, 50 to 85 parts by weight
polyester fiber, and 15 to 25 parts by weight binder fibers;
[0046] c) forming a layered batt having a total thickness of at
least 1.25 centimeters (0.5 inches) wherein one layer contains the
base layer fiber mixture and another layer contains the resilient
layer fiber mixture; and
[0047] d) heating the layered batt to activate the binder fibers
and form a high loft batting.
[0048] The fiber mixtures and layered batt may be formed by any
method that can create low-density webs. For example, clumps of
crimped staple fibers and binder fibers obtained from bales of
fiber can opened by a device such as a picker. Preferably these
fibers are staple fibers having a linear density of about 0.55 to
about 110 dtex per filament (0.5 to 100 denier per filament),
preferably 0.88 to 56 dtex/filament (0.8 to 50 denier/filament)
with the linear density range of about 1 to 33 dtex/filament (0.9
to 30 denier/filament) being most preferred. The fibers generally
have a cut length of about 1.3 cm to 10.2 cm (0.5 to 4 in) and a
preferred crimp frequency of about 2.4 to 5.9 crimps per cm (6 to
about 15 crimps/inch).
[0049] The opened fiber mixture can be then blended by any
available method, such as air conveying, to form a more uniform
mixture. Alternatively, the fibers can be blended to form a uniform
mixture prior to fiber opening in the picker. The blend of fibers
can then be converted into a fibrous web by use of a device such as
a card, although other methods, such as air-laying of the fibers
may be used. The fibrous web can then be sent via conveyor to a
device such as a crosslapper to create a high loft crosslapped
structure by layering individual webs on top of one another in a
zig-zig structure. The rate of fiber opening and crosslapping is
controlled to create high loft crosslapped structures of the
desired height. Representative processes useful in achieving
crosslapped structures, including processes for crosslapping an
air-laid or otherwise formed web on a belt or apron, are well-known
in the art and generally disclosed in U.S. Pat. No. 3,558,029 to
Manns; U.S. Pat. No. 3,877,628 to Asselin et al.; U.S. Pat. No.
4,984,772 to Freund; U.S. Pat. No. 6,195,844 to Jourde et al., and
British Patent Number 1,527,230 to Jowett.
[0050] To create a multilayered high loft batting of this
invention, two or more high loft structures having different
compositions, preferably the compositions of the aforementioned
base and resilient layers, can be made either simultaneously or
sequentially and then overlaid, one on the other, on a conveyor or
belt. This layered high loft web batting is then set by applying
heat, preferably by use of a heated oven and preferably without
compression of the batting, to activate the binder material. The
high loft batting is then cooled to set the binder material.
[0051] In the preferred process, the edges of the layered high loft
batting are then trimmed to provide a batting with a uniform width.
The portion of the high loft batting trimmed is then recycled back
into the process, preferably by processing this material through a
picker, which separates the trimmed edges into individual fibers.
This recycled portion contains fibers from both the base and
resilient layers, and therefore to maintain the color consistency
of the resilient layer the recycled portion is preferably added to
the base layer. However, since the base layer provides integrity to
the layered batting in flame, and the recycled material contains
flammable fibers, the amount of recycled material added to the base
layer must be limited. Preferably, the total amount recycled to the
base sheet is less than about 25 parts by weight of the total
weight of the base sheet. Preferably, through this recycling
process, the base layer can additionally contain polyester fiber in
an amount up to 15 parts by weight and modacrylic fiber in an
amount up to 5 parts by weight of the base layer.
[0052] This invention also includes a fire blocked article
comprising the layered high loft batting described herein.
Preferably, this article is a mattress comprising a quilt panel
incorporating the high loft web batting of this invention. The
mattress quilt panel can be formed by combining layers of ticking
fabric, one or more layers of layered high loft batting of this
invention, optionally foam, and if needed, a scrim backing, which
is used on the side of the mattress quilt that will be facing the
mattress internals.
[0053] The ticking fabric is normally a very durable woven or knit
fabric utilizing any number of weaves, and tends to have basis
weights in the range of 2 to 8 ounces per square yard (68 to 271
grams per square meter). Typical ticking fabrics may contain but
are not limited to cotton, polyester fibers, or rayon fibers. The
foam is typically a polyurethane foam. The scrim backing is
generally a layer of a 0.5-1 oz/yd.sup.2 nonwoven (generally
spunbonded) fabric. The layers of the mattress quilt panel can be
securely bound together by lines of stitching with thread.
[0054] The layered high loft batting of this invention can be
incorporated mattresses, foundations, and/or box springs as a flame
blocking layer. For example, the panels and the borders of
mattresses, foundations, and/or box springs can utilize the
previously described mattress panel quilt or any other variant that
incorporates as a component the layered high loft batting of this
invention. The stitching can be sewn with non-flame retardant
thread, however, a fire-retardant thread, such as one made from
Kevlar.RTM. aramid fiber, is preferred for the stitching,
especially for stitching of the borders of the mattresses,
foundations, and/or box springs.
[0055] This invention further relates to a method of fire blocking
an article, comprising the steps of:
[0056] a) combining a layer of a fabric ticking or upholstery, and
a high loft batting, and optionally a stitch backing layer, the
high loft batting comprising a base layer comprising 10 to 30 parts
by weight heat resistant fibers, 35 to 55 parts by weight of a
cellulose fiber that retains at least 10 percent of its fiber
weight when heated in air to 700.degree. C. at a rate of 20 degrees
C. per minute, and 15 to 25 parts by weight binder material; and a
resilient layer comprising 0 to 50 parts by weight modacrylic
fibers, 50 to 85 parts by weight polyester fiber, and 15 to 25
parts by weight binder material; the base layer comprising 20 to 70
parts by weight and the resilient layer comprising 80 to 30 parts
by weight of the batting, based on the total weight of those two
layers, the batting having a total thickness of at least 1.25
centimeters (0.5 inches),
[0057] b) sewing the layers together to form a fire blocked quilt
or upholstery fabric, and
[0058] c) incorporating the fire blocked quilt or upholstery fabric
into the article.
Test Methods
[0059] ThermoGravametric Analysis. 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 at 50
degrees C.; ramping the temperature at from 10 or 20 degrees C. per
minute from 50 to 1000 degrees C.; using air as the gas, supplied
at 10 ml/minute; and using a 500 microliter ceramic cup (PN
952018.910) sample container.
[0060] 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 {fraction (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 10 to 50 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.
[0061] Thickness. Thickness of the layered batting can be measured
using ASTM D5736-95 (Reapproved 2001).
[0062] Mattress Burn Performance. The Bureau of Home Furnishings
and Thermal Insulation of the Department of Consumer Affairs of the
State of California (3485 Orange Grove Avenue, North Highlands,
Calif. 95660-5595, USA) published Technical Bulletin 603
"Requirements and Test Procedure for Resistance of a Residential
Mattress/Box Spring Set to a Large Open-Flame" dated February 2003
to quantify the flammability performance of mattress sets. The
bulletin was later revised in July 2003, requiring the limit of
Peak Heat Release Rate (PHRR) to be less than 200 kilowatts and the
Total Heat release limit at 10 minutes to be less than 25
megajoules. This protocol provides a means of determining the
burning behavior of mattress/foundation sets by measuring specific
fire test responses when the mattress plus foundation are exposed
to a specified flaming ignition source under well-ventilated
conditions. It is based on the National Institute of Standards and
Technology Publication titled "Protocol of Testing
Mattress/Foundation Sets Using a Pair of Gas Burners" dated
February 2003.
[0063] Test data are obtained that describe the burning during and
subsequent to the application of a specific pair of gas burners
from the point of ignition until (1) all burning of the sleep set
has stopped, (2) a period of 30 minutes has elapsed, or (3)
flashover of the test room appears inevitable. The rate of heat
release from the burning test specimen (the energy generated by the
fire) is measured by oxygen consumption calorimetry. A discussion
of the principles, limitations, and requisite instrumentation are
found in ASTM E 1590 "Standard Test Method of Fire Testing of
Mattresses". Terminology associated with the testing is defined in
ASTM E 176 "Standard Terminology of Fire Standards".
[0064] In general, the test protocol utilizes a pair of propane
burners, designed to mimic the heat flux levels and durations
imposed on a mattress and foundation by burning bedclothes. The
burners impose differing fluxes for differing times on the mattress
top and the side of the mattress/foundation. During and subsequent
to this exposure, measurements are made of the time-dependent heat
release rate from the test specimen.
[0065] The mattress/foundation is placed on top of a short bed
frame that sits on a catch surface. During the testing, the smoke
plume is caught by a hood that is instrumented to measure heat
release rate. For practicality, twin-sized mattresses and
foundations are tested. After ignition by the burners, the specimen
is allowed to burn freely under well-ventilated conditions.
[0066] The test specimen includes a mattress that is placed on
foundation with T-shaped burners set to burn the specimen. One
burner impinges flames on the top surface of the mattress and is
set 39 mm from the surface of the mattress. The second burner
impinges flames vertically on the side of the mattress/foundation
combination and is set 42 mm from the side of the specimen. The
side burner and the top burner are not set at the same place along
the length of the specimen but are offset from on another along the
length approximately 18 to 20 cm. The burners are specially
constructed and aligned per the test method.
[0067] The test specimen is conditioned for 24 hours prior to the
testing at an ambient temperature of above 12 Celsius (54
Fahrenheit) and a relative humidity of less than 70 percent. The
test specimen of mattress and foundation is centered on each other
and the frame and catch surface. If the mattress is 1 to 2 cm
narrower than the foundation the mattress may be shifted until the
sides of the mattress and foundation are aligned vertically. The
burners are aligned and spaced from the specimen per the standard.
Data recording and logging devices are turned on at least one
minute prior to ignition. The burners are ignited and the top
burner is allowed to burn for 70 seconds while the side burner is
allowed to burn for 50 seconds (if possible) and then they are
removed from the area. Data collection continues until all signs of
burning and smoldering have ceased or until one hour has
elapsed.
EXAMPLE
[0068] A two-layered high loft batting having a base layer and a
resilient layer was made, the fibers in both layers being held in
place by use of a copolymer PET sheath/PET core binder fiber having
a melting temperature of 120.degree. C. Conventional carding
lines/garnet machines and crosslappers were used to open and blend
the fibers and form the individual high loft batting layers, which
were combined together and heat set using a gas-fired oven. The
high loft batting was then cooled. A portion of the high loft
batting was recycled back into the cards and the fibers from this
recycled portion became part of the base layer. The base layer,
excluding the recycled material, contained Type 970 Kevlar.RTM.
aramid fiber (available from DuPont) having an individual filament
denier of 2.2 dpf and an average 2" cut length, Type 33AP
Visil.RTM. cellulose fiber (available from Sateri) having an
individual filament denier of 3.5 dpf and an average 50 mm cut
length, and the binder fiber (available from Nan Ya) having an
individual filament denier of 4 dpf and an average cut length of 51
mm. The resilient layer had PET polyester fiber (available from KG)
having an individual filament denier of 15 dpf and an average cut
length of 64 mm, Protex C modacrylic fiber (available from Kaneka)
having an individual filament denier of 7 dpf and an average cut
length of 51 mm, and the same binder fiber as the base layer.
[0069] The test items, fiber blend ratio by weight, basis weight
for base layer and top layer are all shown in the Table. The items
had a thickness in the range of approximately 2.5 to 3.8 cm (1 to
1.5 in).
1 TABLE Base Layer Top Layer Item BW Kevlar .RTM. Visil Binder
Recycle BW Modacrylic PET Binder 1 5 30 50 20 5 50 30 20 osy osy 2
5 30 50 20 7 50 30 20 osy osy 3 5 20 40 20 20 5 20 60 20 osy osy 4
4 20 40 20 20 5 20 60 20 osy osy 5 4 20 40 20 20 5 0 80 20 osy osy
Recycle composition-20% binder, 15% Kevlar .RTM., 25% Visil, 25%
Modacrylic, 15% PET
[0070] The high loft battings were then tested for open flame test
protocol TB 603 in single and double sided mattresses.
[0071] Four single-side mattresses were prepared for testing. Two
of the mattresses incorporated Item #1 underneath the ticking on
the top panel and two of the mattresses incorporated Item #3
underneath the ticking on the top panel. The mattress borders of
all four mattresses utilized a fabric comprised of two spunlaced
layers of fabric as a fire blocker; one spunlaced layer had a basis
weight of 2.5 oz/yd.sup.2 and was comprised of a 50%/50% mixture of
Keviar.RTM. aramid fiber and Visil.RTM. cellulose fiber. The other
spunlaced layer had a basis weight of 4.0 oz/yd.sup.2 and was
comprised of a 33%/67% mixture of Visil.RTM. fiber and Protex C
modacrylic fiber. This same fire blocker was used in the borders of
the foundation. The fire blocker used on the foundation panel was a
single spunlaced layer having a basis weight of 4.0 oz/yd.sup.2 and
was comprised of a 25%/75% mixture of Kevlar.RTM.D aramid fiber and
Visil.RTM. cellulose fiber.
[0072] Four double-sided mattresses were also prepared for testing.
T hey were prepared the same as the single-sided mattresses with
the exceptions that Item #1 was incorporated into two of the
mattresses and Item #4 was incorporated into two of the mattresses,
and, since these were double-side mattresses, the high loft layered
battings were incorporated into both panels of the mattresses. All
other materials were the same.
[0073] When tested, all of the mattress sets had a peak heat
release rate of less than 200 kilowatts within 30 minutes and a
total heat release of less than 25 megajoules within 10 minutes
when tested according to Technical Bulletin 603 of the State of
California, as revised July 2003.
* * * * *