U.S. patent application number 10/803384 was filed with the patent office on 2005-09-22 for modacrylic/cotton/aramid fiber blends for arc and flame protection.
Invention is credited to Zhu, Reiyao.
Application Number | 20050208855 10/803384 |
Document ID | / |
Family ID | 34963940 |
Filed Date | 2005-09-22 |
United States Patent
Application |
20050208855 |
Kind Code |
A1 |
Zhu, Reiyao |
September 22, 2005 |
Modacrylic/cotton/aramid fiber blends for arc and flame
protection
Abstract
Yarns, fabrics and garments contain modacrylic, cotton and
aramid fibers.
Inventors: |
Zhu, Reiyao; (Midlothian,
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: |
34963940 |
Appl. No.: |
10/803384 |
Filed: |
March 18, 2004 |
Current U.S.
Class: |
442/302 ;
442/189; 442/197; 442/198; 442/301; 442/308; 442/310; 442/334;
442/414; 442/415 |
Current CPC
Class: |
Y10T 442/313 20150401;
Y10T 442/3984 20150401; Y10T 442/3065 20150401; D02G 3/443
20130101; Y10T 442/425 20150401; Y10T 442/3976 20150401; Y10T
442/608 20150401; Y10T 442/438 20150401; D10B 2321/101 20130101;
D10B 2331/021 20130101; Y10T 442/3138 20150401; Y10T 442/697
20150401; D10B 2201/02 20130101; D02G 3/047 20130101; Y10T 442/696
20150401 |
Class at
Publication: |
442/302 ;
442/189; 442/197; 442/198; 442/301; 442/308; 442/310; 442/334;
442/414; 442/415 |
International
Class: |
D03D 015/12 |
Claims
What is claimed is:
1. A yarn suitable to provide arc and flame protection comprising:
(a) 40 to 75 weight percent modacrylic fiber, (b) 10 to 40 weight
percent cotton fiber and (c) 1 to 40 weight percent aramid fiber,
said percentages on the basis of components (a), (b) and (c).
2. The yarn of claim 1 comprising: (a) 45 to 60 weight percent
modacrylic fiber (b) 15 to 35 weight percent cotton fiber and (c) 5
to 30 weight percent aramid fiber.
3. The yarn of claim 1 where the fiber includes both para- and
meta-aramid fiber.
4. The yarn of claim 3 wherein the para-aramid fiber is present in
a range from 20 to 40 weight percent and the meta-aramid fiber is
present in a range from 60 to 80 weight percent on a basis of total
aramid fiber.
5. The yarn of claim 4 wherein the para-aramid fiber is present in
a range from 25 to 35 weight percent and the meta-aramid fiber is
present in a range from 65 to 75 weight percent.
6. The yarn of claim 5 which additionally contains an anti-static
component.
7. The yarn of claim 6 wherein the anti-static component is carbon
or metal.
8. The yarn of claim 7 wherein the anti-static component is
carbon.
9. The yarn of claim 1 which additionally contains an anti-static
component.
10. The yarn of claim 9 wherein the anti-static component is
carbon.
11. A fabric suitable to provide an arc and thermal protection
comprising: (a) 40 to 75 weight percent modacrylic fiber, (b) 10 to
40 weight percent cotton fiber and (c) 1 to 40 weight percent
aramid fiber, said percentages on the basis of components (a), (b)
and (c).
12. The fabric of claim 11 comprising: (a) 45 to 60 weight percent
modacrylic fiber (b) 15 to 35 weight percent cotton fiber and (c) 5
to 30 weight percent aramid fiber.
13. The fabric of claim 11 wherein the char length according to
ASTM D-6413-99 is less than 6 inches.
14. The fabric of claim 11 wherein the char length according to
ASTM D-6413-99 is less than 4.5 inches.
15. The fabric of claim 11 wherein the fabric includes fibers of
para- and meta-aramid.
16. The fabric of claim 15 wherein para-aramid fiber is present in
a range from 20 to 40 weight percent and meta-aramid fiber is
present in a range from 60 to 80 weight percent on a basis of total
aramid fiber.
17. The fabric of claim 16 wherein the para-aramid fiber is present
in a range from 25 to 35 weight percent and the meta-aramid fiber
is present in a range from 65 to 75 weight percent.
18. The fabric of claim 11 which additionally contains an
anti-static component.
19. A garment suitable to provide arc and thermal protection: (a)
40 to 75 weight percent modacrylic fiber, (b) 10 to 40 weight
percent cotton fiber and (c) 1 to 40 weight percent aramid fiber,
said percentages on the basis of components (a) (b) and (c).
20. The garment of claim 16 comprising: (a) 45 to 60 weight percent
modacrylic fiber (b) 15 to 35 weight percent cotton fiber and (c) 5
to 30 weight percent aramid fiber.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a blended yarn useful for the
production of fabrics which possess arc and flame protective
properties. This invention also relates to garments produced with
such fabrics.
[0003] 2. Description of Related Art
[0004] Individuals working near energized electrical equipment and
emergency personnel who respond to incidents near electrical
equipment are at risk from electrical arcs and flame hazards which
could result from an arcing event. Electrical arcs are extremely
violent events typically involving thousands of volts and thousands
of amperes of electricity. Electrical arcs are formed in air when
the potential difference (i.e. voltage) between two electrodes
causes the atoms in the air to ionize and become able to conduct
electricity.
[0005] Arc protective and flame resistant garments typically are
uncomfortable to wear due to the poor moisture vapor transport of
the protective fibers incorporated within. Individuals wearing
protective apparel typically experience both tactile discomfort and
heat stress as a result of the protective fibers incorporated in
their protective garments.
[0006] U.S. Pat. No. 5,208,105 to Ichibori et. al. discloses a
flame retarded composite fiber blend comprising a halogen
containing fiber having a large amount of an antimony compound and
at least one fiber selected from the list consisting of natural
fibers and chemical fibers. The fiber blend is woven into a fabric
which is then tested for it Limited Oxygen Index as a measure of
its flame resistance.
[0007] U.S. Pat. No. 5,223,334 to Green discloses a fabric offering
protection from radiant energy due to electrical arcs. Green makes
no disclosure of the use of Modacrylic fibers within the blended
yarn. Also, Green does not disclose a protective fabric formed from
yarns comprising less than 50 percent cotton.
[0008] What is needed is a yarn fabric and garment to provide a
high level of protection when the material is exposed to an
electrical arc and also flame resistance to protect the wearer from
secondary effects.
SUMMARY OF THE INVENTION
[0009] This invention relates to a yarn for use in arc and thermal
protection fabrics and garments comprising:
[0010] (a) 40 to 75 weight percent modacrylic fiber,
[0011] (b) 10 to 40 weight percent cotton fiber and
[0012] (c) 1 to 25 weight percent aramid fiber, said percentages on
the basis of components (a), (b) and (c).
[0013] The yarn is useful for incorporation into a thermally and
arc resistant fabric and a garment especially suited for protecting
workers against electrical arc. Furthermore the fabric and garment
may provide resistance to break open, flame and abrasion.
DETAILED DESCRIPTION OF THE INVENTION
[0014] This invention relates to providing a yarn, fabric and
garment to provide both improved arc protection and flame
resistance. Fabrics and garments comprising flame resistant fibers
of low tensile strength when exposed to the intense thermal stress
of an electrical arc can break open exposing the wearer to
additional injury as a result of the incident energy. Electrical
arcs typically involve thousands of volts and thousands of amperes
of electrical current. The electrical arc is much more intense than
the incident energy such as from flash fire. To offer protection to
a wearer a garment or fabric must resist the transfer to energy
through to the wearer. It is believed that this occurs both by the
fabric absorbing a portion of the incident energy and by the fabric
resisting breakopen. During breakopen a hole forms in the fabric
directly exposing the surface or wearer to the incident energy.
[0015] Yarns, fabrics and garments of this invention when exposed
to the intense thermal stress of an electrical arc resist the
transfer of energy. It is believed that this invention reduces
energy transfer by absorbing a portion of the incident energy and
through charring allows a reduction in transmitted energy.
[0016] Yarns of this invention comprise a blend of modacrylic
fiber, cotton fiber, and aramid fiber. Typically, yarns of this
invention comprise 40 to 75 weight percent modacrylic fiber, 10 to
40 weight percent cotton fiber, and 1 to 40 weight percent aramid
fiber. Preferably, yarns of this invention comprise 45 to 65 weight
percent modacrylic fiber, 15 to 35 weight percent cotton fiber, and
5 to 30 weight percent aramid fiber. The above percentages are on
the basis of the three named components.
[0017] By "yarn" is meant an assemblage of fibers spun or twisted
together to form a continuous strand, which can be used in weaving,
knitting, braiding, or plaiting, or otherwise made into a textile
material or fabric.
[0018] By modacrylic fiber it is meant acrylic synthetic fiber made
from a polymer comprising primarily acrylonitrile. Preferably the
polymer is a copolymer comprising 30 to 70 weight percent of a
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, acyrlamide, methylacrylamide, vinyl
acetate, etc.
[0019] The preferred modacrylic fibers of 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 & 5,506,042 having 8 to
40 weight percent of an antimony compound.
[0020] Within the yarns of this invention modacrylic fiber provides
a flame resistant char forming fiber with an LOI typically at least
28 depending on the level of doping with antimony derivatives.
Modacrylic fiber is also resistant to the spread of damage to the
fiber due to exposure to flame. Modacrylic fiber while highly flame
resistant does not by itself provide adequate tensile strength to a
yarn or fabric made from the yarn to offer the desired level of
breakopen resistance when exposed to an electrical arc.
[0021] As used herein, "aramid" is meant a polyamide wherein at
least 85% of the amide (--CONH--) linkages are attached directly to
two aromatic rings. Additives can be used with the aramid and, 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. Suitable aramid fibers are described in
Man-Made Fibers--Science and Technology, Volume 2, Section titled
Fiber-Forming Aromatic Polyamides, page 297, W. Black et al.,
Interscience Publishers, 1968. Aramid fibers are, also, disclosed
in U.S. Pat. Nos. 4,172,938; 3,869,429; 3,819,587; 3,673,143;
3,354,127; and 3,094,511. M-aramid are those aramids where the
amide linkages are in the meta position relative to each other, and
p-aramids are those aramids where the amide linkages are in the
para position relative to each other. In the practice of this
invention the aramids most often used are poly(paraphenylene
terephthalamide) and poly(metaphenylene isophthalamide).
[0022] It is within the scope of this invention that a single type
of aramid fiber can be employed. Illustratively, either a
meta-aramid or para-aramid fiber can be used.
[0023] However, in a preferred mode both para-aramid and
meta-aramid fibers are employed. An illustrative percentage is 20
to 40 weight percent para-aramid fibers and 60 to 80 weight percent
meta-aramid fibers. The above percentages are on a basis of the
aramid only. A preferred range of these two aramids is 25 to 35
weight percent para-aramid and 65 to 75 weight percent
meta-aramid.
[0024] Within yarns of this invention cotton fibers provide a flame
resistant fiber that provides moisture transport within the yarn.
Garments comprising cotton fibers improve the comfort of the wearer
by wicking moisture away from the wearer. By allowing perspiration
to wick away the heat stress to a wearer who is exerting themselves
is reduced.
[0025] Additionally, to the yarn, fabric, or garment of this
invention may be added an antistatic component such as steel fiber,
carbon fiber, or a carbon coating to an existing fiber. The
conductivity of carbon or a metal such as steel when incorporated
in a yarn, fabric, or garment of this invention provides an
electrical conduit to assist in dissipating the buildup of static
electricity. Static electrical discharges can be hazardous for
workers working with sensitive electrical equipment or near
flammable vapors.
[0026] Yarns of this invention may be produced by any of the yarn
spinning techniques commonly known in the art such as but not
limited to ring spinning, core spinning, and air jet spinning or
higher air spinning techniques such as Murata air jet spinning
where air is used to twist staple fibers into a yarn. Typically the
single yarns produced by any of the common techniques are then
plied together to form a ply-twisted yarn comprising at least two
single yarns prior to being converted into a fabric.
[0027] To provide protection from the intense thermal stresses
caused by electrical arcs it is desirable that an arc protective
fabric and garments formed from that fabric possess features such
as an LOI above the concentration of oxygen in air for flame
resistance, a short char length indicative of slow propagation of
damage to the fabric, and good breakopen resistance to prevent
incident energy from directly impinging on the surfaces below the
protective layer.
[0028] Thermally protective garments such as firefighter turnout
gear typically provide protection against the convective heat
generated by an open flame. Such protective garments when exposed
to the intense energy generated by an electrical arc can breakopen
(i.e. an opening form in the fabric) resulting in the energy
penetrating the garment and causing severe injury to the wearer.
Fabrics of this invention provide both protection against the
convective heat of an open flame and offer increased resistance to
breakopen and energy transfer when exposed to an electrical arc.
The thickness of the fabric and overall weight of a protective
garment such as a firefighter turnout coat typically worn can cause
heat stress to a wearer by trapping body heat and perspiration next
to the skin. Fabrics of this invention comprise a moisture
transport fiber such as cotton within yarns of the fabric to
provide a means for moisture due to perspiration to wick away from
the wearer thus improving comfort and reducing heat stress.
[0029] Basis weight is a measure of the weight of a fabric per unit
area. Typical units include ounces per square yard and grams per
square centimeter. The basis weights reported in this specification
are reported in ounces per square yard (OPSY). As the amount of
fabric per unit area increases the amount of material between a
potential hazard and the subject to be protected increases. An
increase in the basis weight of a material suggests that a
corresponding increase in protective performance will be observed.
An increase in basis weight of fabrics of this invention results in
increased breakopen resistance, increased thermal protection
factor, and increased arc protection. Basis weights of fabrics of
this invention are typically greater than about 8.0 opsy,
preferably greater than about 8.7 opsy, and most preferably greater
than about 9.5 opsy. It is believed fabrics of this invention with
basis weights greater than 12 opsy would show increased stiffness
and would thereby reduce the comfort of a garment produced from
such fabric.
[0030] Char length is a measure of the flame resistance of a
textile. A char is defined as a carbonaceous residue formed as the
result of pyrolysis or incomplete combustion. The char length of a
fabric under the conditions of test of ASTM 6413-99 as reported in
this specification is defined as the distance from the fabric edge,
which is directly exposed to the flame to the furthest point of
visible fabric damage after a specified tearing force has been
applied. Preferably fabric of this invention have a char length of
less than 6 inches and preferably less than 4.5 inches.
[0031] Fabrics of this invention may be used as a single layer or
as part of a multi-layer protective garment. The yarns of this
invention may be present in either the warp or fill of the fabric.
Preferably the yarns of this invention are present in both the warp
and fill of the resulting fabric.
Test Methods
[0032] Abrasion Test
[0033] The abrasion performance of fabrics of this invention is
determined in accordance with ASTM D-3884-01 "Standard Guide for
Abrasion Resistance of Textile Fabrics (Rotary Platform, Double
Head Method)".
[0034] Arc Resistance Test
[0035] The arc resistance of fabrics of this invention is
determined in accordance with ASTM F-1959-99 "Standard Test Method
for Determining the Arc Thermal Performance Value of Materials for
Clothing". Preferably fabrics of this invention have an arc
resistance of at least 0.8 calories and more preferably at least
1.2 calories per square centimeter per opsy.
[0036] Grab Test
[0037] The grab resistance of fabrics of this invention is
determined in accordance with ASTM D-5034-95 "Standard Test Method
for Breaking Strength and Elongation of Fabrics (Grab Test)".
[0038] Limited Oxygen Index Test
[0039] The limited oxygen index (LOI) of fabrics of this invention
is determined in accordance with ASTM G-125-00 "Standard Test
Method for Measuring Liquid and Solid Material Fire Limits in
Gaseous Oxidants".
[0040] Tear Test
[0041] The tear resistance of fabrics of this invention is
determined in accordance with ASTM D-5587-03 "Standard Test Method
for Tearing of Fabrics by Trapezoid Procedure".
[0042] Thermal Protection Performance Test
[0043] The thermal protection performance of fabrics of this
invention is determined in accordance with NFPA 2112 "Standard on
Flame Resistant Garments for Protection of Industrial Personnel
Against Flash Fire".
[0044] Vertical Flame Test
[0045] The char length of fabrics of this invention is determined
in accordance with ASTM D-6413-99 "Standard Test Method for Flame
Resistance of Textiles (Vertical Method)".
[0046] The term thermal protective performance (or TPP) relates to
a fabric's ability to provide continuous and reliable protection to
a wearer's skin beneath a fabric when the fabric is exposed to a
direct flame or radiant heat.
[0047] Limited Oxygen Index (LOI)
[0048] From ASTM G125/D2863
[0049] The minimum concentration of oxygen, expressed as a volume
percent, in a mixture of oxygen and nitrogen that will just support
flaming combustion of a material initially at room temperature
under the conditions of ASTM D2863.
[0050] To illustrate the present invention, the following examples
are provided. All parts and percentages are by weight and degrees
in Celsius unless otherwise indicated.
EXAMPLES
[0051] Modacrylic/Cotton/Aramid Fabric
Example 1
[0052] A comfortable and durable fabric was prepared having in the
both warp and fill of ring spun yarns of intimate blends of
Nomex.RTM. type 462, Kevlar.RTM. 29, Modacrylic and Cotton.
Nomex.RTM. type 462 is 93% of poly(m-phenylene
isophthalamide)(MPD-I), 5% of poly(p-phenylene
terephthalamide)(PPD-T) and 2% of static dissipative fibers (P-140
from DuPont), Modacrylic is ACN/polyvinylidene chloride co-polymer
with 15% antimony (known as Protex.RTM.M), and Kevlar.RTM. 29 is
poly(p-phenylene terephthalamide)(PPD-T).
[0053] A picker blend sliver of 10 wt. % of Nomex.RTM. type 462, 10
wt. % of Kevlar.RTM. 29, 55 wt. % of Modacrylic and 25 wt. % of
cotton was prepared and processed by the conventional cotton system
into a spun yarn having twist multiply 3.7 using a ring spinning
frame. The yarn so made was 24.6 tex (24 cotton count) single yarn.
Two single yarns are then plied on the plying machine to make a
two-ply yarn. Using similar process and same twist and blend ratio,
a 32.8 tex (18 cotton count) yarn was made for using as fill yarn.
The yarns were then two-plied to form a ply yarn.
[0054] The Nomex.RTM./Kevlar.RTM./Modacrylic/Cotton yarns were used
as the warp and fill in a shuttle loom in a 3.times.1 twill
construction. The greige twill fabric had a construction of 24
ends.times.15 picks per cm (60 ends.times.39 picks per inch), and
basis weight of 271.3 g/m{circumflex over ( )}2 (8 oz/yd{circumflex
over ( )}2). The greige twill fabric prepared as described above
was scoured in hot water and dried under low tension. The scoured
fabric was then jet dyed using basic dye.
Example 2
[0055] A comfortable and durable fabric was prepared having in the
both warp and fill of ring spun yarns of intimate blends of
Nomex.RTM. type 462, Kevlar.RTM. 29, Modacrylic and Cotton.
Nomex.RTM. type 462 is 93% of poly(m-phenylene
isophthalamide)(MPD-I), 5% of poly(p-phenylene
terephthalamide)(PPD-T) and 2% of static dissipative fibers (P-140
from DuPont), Modacrylic is ACN/polyvinylidene chloride co-polymer
with 15% antimony (known as Protex.RTM.M), and Kevlar.RTM. 29 is
poly(p-phenylene terephthalamide)(PPD-T).
[0056] A picker blend sliver of 10 wt. % of Nomex.RTM. type 462, 10
wt. % of Kevlar.RTM. 29, 45 wt. % of Modacrylic and 35 wt. % of
cotton was prepared and processed by the conventional cotton system
into a spun yarn having twist multiply 3.7 using a ring spinning
frame. The yarn so made was 24.6 tex (24 cotton count) single yarn.
Two single yarns are then plied on the plying machine to make a
two-ply yarn. Using similar process and same twist, a 32.8 tex (18
cotton count) yarn with blend of Nomex.RTM. type 462/Modacrylic at
50/50 ratio was made for using as fill yarn. The yarns were then
two-plied to form a ply yarn.
[0057] The Nomex.RTM.)/Kevlar.RTM./Modacrylic/cotton yarn was used
as the warp and Nomex.RTM./Modaxrylic yarn as the fill in a shuttle
loom in a 3.times.1 twill construction. The greige twill fabric had
a construction of 23 ends.times.16 picks per cm (58 ends.times.40
picks per inch), and basis weight of 264.5 g/m{circumflex over (
)}2 (7.8 oz/yd{circumflex over ( )}2). The greige twill fabric
prepared as described above was scoured in hot water and dried
under low tension. The scoured fabric was then jet dyed using basic
dye.
[0058] The following Table illustrates measured properties of
Examples 1 and 2.
1 Example 1 Example 2 Fabric Composition Fabric 2 .times. 1 2
.times. 1 Construction twill twill Basis Weight 6.7 6.7 (opsy) Char
Length 4 .times. 4 3.3 .times. 3.6 (in) WarpxFill TPP Value 11.8
12.5 (cal/cm.sup.2) Grab Strength 100 .times. 96 118 .times. 89
(lbf) WarpxFill Trap Tear (lbf) 13.6 .times. 11.7 13.8 .times. 10.8
WarpxFill Taber Abrasion 352 317 (Cycles) CS- 10/1000 g
* * * * *