U.S. patent application number 16/970725 was filed with the patent office on 2020-12-17 for non woven fabric.
This patent application is currently assigned to Toray Industries, Inc.. The applicant listed for this patent is Toray Industries, Inc.. Invention is credited to Yao Chen, Masaru Harada, Hiroshi Tsuchikura.
Application Number | 20200392657 16/970725 |
Document ID | / |
Family ID | 1000005064509 |
Filed Date | 2020-12-17 |
![](/patent/app/20200392657/US20200392657A1-20201217-D00001.png)
United States Patent
Application |
20200392657 |
Kind Code |
A1 |
Chen; Yao ; et al. |
December 17, 2020 |
NON WOVEN FABRIC
Abstract
In order to provide a non-woven fabric with excellent flame
retardancy and flame shielding performance, and even also with
carding process-passing and durability, there is provided a
non-woven fabric including: a non-melting fiber A that has a
high-temperature shrinkage ratio of 3% or less; a thermoplastic
fiber B that has an LOI value of 25 or more in accordance with JIS
K 7201-2 (2007); and a thermoplastic fiber C that has an LOI value
of less than 25 in accordance with JIS K 7201-2 (2007) and a crimp
number of 8 (crimps/25 mm) or more in accordance with JIS L 1015
(2000).
Inventors: |
Chen; Yao; (Otsu-shi, Shiga,
JP) ; Harada; Masaru; (Otsu-shi, Shiga, JP) ;
Tsuchikura; Hiroshi; (Otsu-shi, Shiga, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toray Industries, Inc. |
Tokyo |
|
JP |
|
|
Assignee: |
Toray Industries, Inc.
Tokyo
JP
|
Family ID: |
1000005064509 |
Appl. No.: |
16/970725 |
Filed: |
February 20, 2019 |
PCT Filed: |
February 20, 2019 |
PCT NO: |
PCT/JP2019/006296 |
371 Date: |
August 18, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D04H 1/4366 20130101;
D04H 1/4342 20130101; D04H 1/46 20130101; D04H 1/4382 20130101;
D10B 2401/041 20130101; D04H 1/435 20130101 |
International
Class: |
D04H 1/4382 20060101
D04H001/4382; D04H 1/46 20060101 D04H001/46; D04H 1/435 20060101
D04H001/435; D04H 1/4366 20060101 D04H001/4366; D04H 1/4342
20060101 D04H001/4342 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 1, 2018 |
JP |
2018-036188 |
Claims
1. A non-woven fabric comprising: a non-melting fiber A that has a
high-temperature shrinkage ratio of 3% or less; a thermoplastic
fiber B that has an LOI value of 25 or more in accordance with JIS
K 7201-2 (2007); and a thermoplastic fiber C that has an LOI value
of less than 25 in accordance with JIS K 7201-2 (2007) and a crimp
number of 8 (crimps/25 mm) or more in accordance with JIS L 1015
(2000).
2. The non-woven fabric according to claim 1, wherein the
thermoplastic fiber C is contained a 20 to 50% by mass in 100% by
mass of the non-woven fabric.
3. The non-woven fabric according to claim 1, wherein the
non-melting fiber A is contained at 10% by mass or more in 100% by
mass of the non-woven fabric.
4. The non-woven fabric according to claim 1, wherein the
thermoplastic fiber B is contained at 20% by mass or more in 100%
by mass of the non-woven fabric.
5. The non-woven fabric according to claim 1, wherein the
non-melting fiber A has a thermal conductivity of 0.060 W/mK or
less.
6. The non-woven fabric according to claim 1, wherein the
non-melting fiber A is one or more selected from a flame-resistant
fiber and a meta-aramid fiber.
7. The non-woven fabric according to claim 1, wherein the
thermoplastic fiber B has a glass transition temperature of
120.degree. C. or lower.
8. The non-woven fabric according to claim 1, wherein the
thermoplastic fiber B is a fiber of at least one resin selected
from the group of a flame-retardant polyester fiber, an anisotropic
melt polyester, a flame-retardant poly(acrylonitrile butadiene
styrene), a flame-retardant polysulfone, a
poly(ether-ether-ketone), a poly(ether-ketone-ketone), a polyether
sulfone, a polyarylate, a polyarylene sulfide, a polyphenylsulfone,
a polyetherimide, a polyamideimide, and a mixture thereof.
9. The non-woven fabric according to claim 1, wherein the
thermoplastic fiber B contains a sulfur atom.
10. The non-woven fabric according to claim 1, wherein the
non-woven fabric is 50 g/m.sup.2 or more in weight per unit area
and 50 kg/m.sup.3 or less in density.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is the U.S. National Phase application of
PCT/JP2019/006296, filed Feb. 20, 2019, which claims priority to
Japanese Patent Application No. 2018-036188, filed Mar. 1, 2018,
the disclosures of each of these applications being incorporated
herein by reference in their entireties for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to a non-woven fabric.
BACKGROUND OF THE INVENTION
[0003] Conventionally, non-woven fabrics have been used which are
obtained from synthetic fibers made of synthetic polymers such as
polyamide, polyester, and polyolefin as fiber materials, but these
synthetic polymers, which usually have no flame retardancy, are
often, in a raw material stage, or after being made into fibers or
non-woven fabrics, subjected to some sort of flame retardant
treatment.
[0004] Various methods have been proposed as methods for obtaining
flame-retardant non-woven fabrics. The methods include, for
example, a method in which a polymer obtained by copolymerizing a
flame-retardant component is spun into a non-woven fabric, a method
in which a drug with flame-retardant effect is kneaded into a
polymer in an original yarn stage and spun into a non-woven fabric,
and a method in which a flame-retardant component is attached to a
non-woven fabric in post-processing. More specifically, Patent
Document 1 discloses a flame-retardant fiber sheet obtained by
treating a fiber sheet with a binder composed of a phosphoric
acid-based flame retardant and a polyester resin (Patent Document
1). Patent Document 2 also discloses a flame-retardant non-woven
fabric obtained by adding a flame-retardant binder to a non-woven
fabric including polyphenylene sulfide fibers and polyester
fibers.
[0005] Furthermore, methods for obtaining a flame-retardant
non-woven fabrics also include a method in which a spun fiber is
subjected to a specific treatment to impart flame retardancy, and
made into a non-woven fabric, and a method in which with the use of
a flame-retardant material as a raw material itself for fibers, the
material is spun and made into a non-woven fabric. For example,
Patent Document 3 discloses a non-woven fabric composed of
flame-resistant fibers provided with flame retardancy by a
treatment after spinning or fibers provided with flame retardancy
by polymerizing a specific raw material, and furthermore, Patent
Document 4 discloses a non-woven fabric including flame-resistant
fibers provided with high flame shielding performance by a
treatment after spinning and polyphenylsulfone fibers.
PATENT DOCUMENTS
[0006] Patent Document 1: Japanese Patent Laid-open Publication No.
2013-169996
[0007] Patent Document 2: Japanese Patent Laid-open Publication No.
2012-144818
[0008] Patent Document 3: Japanese Patent Laid-open Publication No.
JP 2003-129362
[0009] Patent Document 4: International Publication No.
2017/6807
SUMMARY OF THE INVENTION
[0010] Although the methods described in Patent Documents 1 and 2
are the simplest methods as methods for imparting flame retardancy,
the attached flame retardant is likely to fall off, and even if the
flame retardant has an excellent flame retardant effect, the flame
retardant still has a problem in terms of durability.
[0011] In addition, the non-woven fabric described in Patent
Document 3 is obtained with the use of a flame-resistant fiber that
has a high limiting oxygen index, LOI value, but the fiber is
likely to fall off in passing through a carding machine, and in the
end, still has problems in terms of both flame retardancy and
workability. Furthermore, the non-woven fabric described in Patent
Document 4 contains the flame-resistant fibers and the
polyphenylsulfone (PPS), and thus has high flame retardancy and
flame shielding performance, but also have room for improvement in
terms of the carding process-passing of the flame-resistant fibers
and PPS fiber.
[0012] The present invention has been achieved in view of the
problems with such conventional flame-retardant non-woven fabrics,
and an object of the invention to provide a non-woven fabric with
excellent flame retardancy and flame shielding performance, and
even also with carding process-passing and durability.
[0013] The present invention adopts any of the following means in
order to solve the above-mentioned problems.
[0014] (1) A nonwoven fabric characterized by including: a
non-melting fiber A that has a high-temperature shrinkage ratio of
3% or less; a thermoplastic fiber B that has an LOI value of 25 or
more in accordance with JIS K 7201-2 (2007); and a thermoplastic
fiber C that has an LOI value of less than 25 in accordance with
JIS K 7201-2 (2007) and a crimp number of 8 (crimps/25 mm) or more
in accordance with JIS L 1015 (2000).
[0015] (2) The non-woven fabric according to the foregoing (1),
characterized in that the thermoplastic fiber C is contained at 20
to 50% by mass in 100% by mass of the non-woven fabric.
[0016] (3) The non-woven fabric according to the foregoing (1) or
(2), characterized in that the non-melting fiber A is contained at
10% by mass or more in 100% by mass of the non-woven fabric.
[0017] (4) The non-woven fabric according to any of the foregoing
(1) to (3), characterized in that the thermoplastic fiber B is
contained at 20% by mass or more in 100% by mass of the non-woven
fabric.
[0018] (5) The non-woven fabric according to any of the foregoing
(1) to (4), characterized in that the non-melting fiber A has a
thermal conductivity of 0.060 W/mK or less in accordance with
ISO22007-3 (2008).
[0019] (6) The non-woven fabric according to any of the foregoing
(1) to (5), characterized in that the non-melting fiber A is one or
more selected from a flame-resistant fiber and a meta-aramid
fiber.
[0020] (7) The non-woven fabric according to any of the foregoing
(1) to (6), characterized in that the thermoplastic fiber B has a
glass transition temperature of 120.degree. C. or lower.
[0021] (8) The non-woven fabric according to any of the foregoing
(1) to (7), characterized in that the thermoplastic fiber B is a
fiber of at least one resin selected from the group of a
flame-retardant polyester fiber, an anisotropic melt polyester, a
flame-retardant poly(acrylonitrile butadiene styrene), a
flame-retardant polysulfone, a poly(ether-ether-ketone), a
poly(ether-ketone-ketone), a polyether sulfone, a polyarylate, a
polyarylene sulfide, a polyphenylsulfone, a polyetherimide, a
polyamideimide, and mixtures thereof.
[0022] (9) The non-woven fabric according to any of the foregoing
(1) to (8), characterized in that the thermoplastic fiber B
contains a sulfur atom.
[0023] (10) The non-woven fabric according to any of foregoing (1)
to (9), characterized in that the non-woven fabric is 50 g/m.sup.2
or more in weight per unit area and 50 kg/m.sup.3 or less in
density.
[0024] The non-woven fabric according to embodiments of the present
invention is configured as mentioned above, thereby providing a
non-woven fabric with excellent flame retardancy and flame
shielding performance, and even also with carding process-passing
and durability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The FIGURE is a diagram for explaining an evaluation test
method for flame shielding performance.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0026] The present invention has been found to provide a non-woven
fabric including: a non-melting fiber A that has a high-temperature
shrinkage ratio of 3% or less; a thermoplastic fiber B that has an
LOI value of 25 or more in accordance with JIS K 7201-2 (2007); and
a thermoplastic fiber C that has an LOI value of less than 25 in
accordance with JIS K 7201-2 (2007) and a crimp number of 8
(crimps/25 mm) or more in accordance with JIS L 1015 (2000),
thereby allowing the above-mentioned problems to be solved.
[0027] In embodiments of the present invention, the non-melting
fiber A that has a high-temperature shrinkage ratio of 3% or less
constitutes the non-woven fabric together with the thermoplastic
fibers B and C and the like. When a flame approaches the non-woven
fabric to apply heat to the non-woven fabric, the thermoplastic
fiber C first starts to melt, the thermoplastic fibers B
subsequently melts, and the melting thermoplastic fibers B and C
spread in the form of a thin film along the surface of the
non-melting fiber A (aggregate). When the temperature further
rises, the fibers A to C are all carbonized, but since the
high-temperature shrinkage ratio of the non-melting fiber A is 3%
or less, the non-woven fabric is less likely to shrink even at high
temperatures and less likely to have holes, and thus capable of
blocking the flame. In this respect, the high-temperature shrinkage
of the non-melting fiber A is preferably lower, but the
high-temperature shrinkage ratio is preferably -5% or more, because
the structure collapses and then causes holes also if the fiber
significantly expands due to heat even without shrinking. Above
all, the high-temperature shrinkage ratio is preferably 0 to
2%.
[0028] It is to be noted that the high-temperature shrinkage ratio
is a value determined by: (i) after leaving a fiber, which is a raw
material for the non-woven fabric, in the standard state
(20.degree. C., relative humidity: 65%) for 12 hours, measuring the
original length L0 with a tension of 0.1 cN/dtex applied to the
fiber; (ii) without applying any load to the fiber, exposing the
fiber to a dry heat atmosphere at 290.degree. C. for 30 minutes,
sufficiently cooling the fiber in the standard state (20.degree.
C., relative humidity: 65%), and then measuring the length L1 with
a tension of 0.1 cN/dtex further applied to the fiber; and (iii)
the following formula from L0 and L1.
High-Temperature Shrinkage Ratio=[(L0-L1)/L0].times.100(%)
[0029] In addition, it is preferable to use, as the non-melting
fiber A, a fiber that has a thermal conductivity of 0.060 W/mK or
less. In the case where the thermal conductivity of the non-melting
fiber A falls within this range, the non-melting fiber A also has
excellent thermal insulation performance. It is to be noted that
the thermal conductivity [W/mK] is a basic thermal constant of a
material, which refers to the heat transfer coefficient of the
simple material. The thermal conductivity represents the ease of
heat transfer in a material, and refers to the value obtained by
dividing the heat flux (thermal energy that passes through a unit
area per unit time) by the temperature difference between the upper
and lower surfaces of the material. Specifically, the thermal
conductivity of the fiber is determined from the following formula
based on the results of measuring the thermal diffusivity, the
specific heat, and the specific gravity as follows: a non-woven
fabric test piece of 0.5 mm in thickness is prepared with the use
of the fiber to be measured, and the thermal diffusivity of the
test piece, the specific heat of the test piece, and the specific
gravity of the test piece are measured respectively in accordance
with ISO22007-3 (2008), JIS K7123 (1987), and JIS K7112 (1999).
Thermal Conductivity=Thermal Diffusivity.times.Specific
Heat.times.Specific Gravity
[0030] In embodiments of the present invention, the non-melting
fiber A refers to a fiber that maintains its fiber shape without
liquefying when the fiber is exposed to a flame. The non-melting
fiber for use in the present invention may be any fiber as long as
the above-mentioned high-temperature shrinkage ratio falls within
the range specified by the present invention, and specific examples
thereof include meta-aramid fibers and flame-resistant fibers.
[0031] In general, meta-aramid fibers have high high-temperature
shrinkage ratios, and fails to satisfy the high-temperature
shrinkage ratio specified in the present invention. However,
meta-aramid fibers modified to have high-temperature shrinkage
ratio within the range specified in the present invention by
reducing the high-temperature shrinkage ratio can be suitably used
because the fibers are high in elasticity and capable of enhancing
the sewability of non-woven fabrics. The flame-resistant fiber is a
fiber selected from acrylonitrile-based, Pitch-based,
cellulose-based, and phenol-based fibers, and etc. as a raw
material and subjected to a flame resistant treatment. These may be
used alone, or two or more thereof may be used together.
[0032] Above all, flame-resistant fibers are preferred from the
viewpoint of low high-temperature shrinkage ratio, and among
various flame-resistant fibers, acrylonitrile-based flame-resistant
fibers are preferably used as fibers that are small in specific
gravity, flexible, and excellent in flame retardancy. Such
flame-resistant fibers are obtained by heating and then oxidizing
acrylic fibers as precursors in high-temperature air.
[0033] Examples of commercially available non-melting fibers A that
can be used in the present invention include Pyromex from TOHO
TENAX CO., LTD., in addition to the flame-resistant fiber "PYRON"
(registered trademark) manufactured by Zoltek, used in Examples and
Comparative Examples described later.
[0034] The excessively low content of the non-melting fiber A in
the non-woven fabric makes the function as an aggregate more likely
to be inadequate, whereas the excessively high content thereof
makes the thermoplastic fiber less likely to spread in an adequate
film form. Thus, the content of the non-melting fiber A in the
non-woven fabric is preferably 10% by mass or more, further within
the range of 15 to 60% by mass, most preferably within the range of
30 to 50% by mass.
[0035] Next, the thermoplastic fiber B, which will spread as a
filmy substance, has an LOI value of 25 or more in accordance with
JIS K7201-2 (2007), whereas the thermoplastic fiber C has an LOI
value of less than 25.
[0036] The LOI value refers to the volume percentage of the minimum
oxygen amount required to sustain combustion of a substance in a
mixed gas of nitrogen and oxygen, and the substance can be
considered less flammable as the LOI value is increased. Thus, the
thermoplastic fiber B that has an LOI value of 25 or more is less
flammable, and even if the fiber is lighted, the fire is
extinguished immediately when the fire source is kept away. In
addition, typically, the slightly burnt area has a carbonized film
formed, and so the carbonized part prevents fire spreading. In
contrast, the thermoplastic fiber C that has a LOI value of less
than 25 continues to burn without fire extinguishing even if the
fire source is kept away. Thus, when heat is applied, the
thermoplastic fibers C starts to melt before the thermoplastic
fibers B does.
[0037] The LOI value of the thermoplastic fiber B is preferably 55
or less, more preferably within the range of 25 to 50, from the
viewpoint of forming a carbonized film at high temperature. In
contrast, the LOI value of the thermoplastic fiber C is preferably
15 or more, more preferably 18 or more and less than 25 from the
viewpoint of the speed of carbonized film formation.
[0038] The thermoplastic fiber B for use in the present invention
may be any fiber as long as the fiber has an LOI value within the
range specified in the present invention, and specific examples
include fibers composed of a thermoplastic resin selected from the
group of flame-retardant polyester fibers (polyethylene
terephthalate fibers, polytrimethylene terephthalate fibers,
polyalkylene terephthalate fibers, and etc.), anisotropic melt
polyesters, flame-retardant poly(acrylonitrile butadiene styrene),
flame-retardant polysulfones, poly(ether-ether-ketone),
poly(ether-ketone-ketone), polyether sulfones, polyarylates,
polyarylene sulfides, polyphenylsulfones, polyetherimides,
polyamideimides, and mixtures thereof. These may be used alone, or
two or more thereof may be used together.
[0039] When the glass transition temperature of the thermoplastic
fiber B is 120.degree. C. or lower, the binder effect for
maintaining the form as a non-woven fabric can be achieved at a
relatively low temperature, thus increasing the apparent density
and increasing the strength, which is preferred. Above all, from
the viewpoint of high LOI value and availability, most preferred
are polyphenylene sulfide fibers (hereinafter, also referred to as
PPS fibers). It is to be noted that the binder effect mentioned
above means that the thermoplastic fiber is melted or softened by
heat and fused to other fibers. Furthermore, the thermoplastic
fiber B preferably contains a sulfur atom as a fiber. In such a
case, preferred are not only a fiber composed of a resin containing
a sulfur atom, but also a fiber with a sulfur atom added thereto by
subsequent processing.
[0040] The PPS fiber preferably used in embodiments of the present
invention is a synthetic fiber composed of a polymer in which a
polymer structural unit has --(C.sub.6H.sub.4--S)-- as a main
structural unit. Typical examples of these PPS polymers include
polyphenylene sulfides, polyphenylene sulfide sulfones,
polyphenylene sulfide ketones, random copolymers thereof, block
copolymers, and mixtures thereof. Desirable as a particularly
preferred PPS polymer is a polyphenylene sulfide containing a
p-phenylene unit represented by --(C.sub.6H.sub.4--S)-- as a main
structural unit of the polymer, preferably at 90 mol % or more.
Desirable from the viewpoint of mass is a polyphenylene sulfide
containing the p-phenylene unit at 80% by mass, and further 90% by
mass or more.
[0041] Further, the PPS fiber is preferably used in the case of
obtaining a non-woven fabric by a papermaking method as mentioned
later, and in such a case, the fiber length preferably falls within
the range of 2 to 38 mm, more preferably within the range of 2 to
10 mm. The fiber length falls within the range of 2 to 38 mm,
thereby allowing the fiber to be uniformly dispersed in a stock
solution for papermaking, and the fiber has the tensile strength
required to pass a drying step in a wet state (wet-web) immediately
after papermaking. In addition, regarding the thickness of the PPS
fiber, the single fiber fineness preferably falls within the range
of 0.1 to 10 dtex, because the fiber can be uniformly dispersed in
the stock solution for papermaking without agglomeration.
[0042] As a method for producing the PPS fiber, a method is
preferred in which the polymer that has the above-mentioned
phenylene sulfide structural unit is melted at a temperature equal
to or higher than its melting point and spun from a spinneret into
a fibrous form. The spun fiber is an undrawn PPS fiber as it is.
The undrawn PPS fiber mostly has an amorphous structure, and with
heat applied thereto, can act as a binder for binding fibers to
each other. On the other hand, because such fibers have poor
dimensional stability to heat, drawn fibers are commercially
available, the drawn fibers having strength and thermal dimensional
stability improved through spinning followed by heat-drawing for
molecular orientation.
[0043] The content of the thermoplastic fiber B in the non-woven
fabric as mentioned above is preferably 10% by mass or more, more
preferably 20% by mass or more, in order to reliably form a filmy
substance and further improve the flame retardancy and flame
shielding performance. On the other hand, the upper limit is
preferably 55% by mass or less. Moreover, the content ratio most
preferably falls within the range of 30 to 50% by mass.
[0044] In contrast, the LOI value of the thermoplastic fiber C for
use in the present invention is less than 25, but at the same time,
the crimp number in accordance with JIS L 1015 (2000) is 8
(crimps/25 mm) or more. As described above, in embodiments of the
present invention, the thermoplastic fiber B with an LOI value of
25 or more and the thermoplastic fiber C with an LOI value of less
than 25 are used in mixture. While fibers with LOI values of 25 or
more are less likely to be crimped, thus relatively straight, and
more likely to fall off in processing non-woven fabrics,
thermoplastic fibers C with an LOI value of less than 25 are more
likely to crimped as mentioned above, and less likely to fall off
with the aid of the three-dimensional spiral structure obtained by
crimping. Therefore, the use of the thermoplastic fibers B and C in
mixture makes not only the thermoplastic fiber C but also the
thermoplastic fiber B less likely to fall off with the aid of the
thermoplastic fiber C crimped, thereby providing a non-woven fabric
that has excellent flame retardancy and flame shielding performance
due to the coating effect, and moreover, also has excellent carding
process-passing, durability, and quality.
[0045] It is to be noted that the excessively large crimp number of
the thermoplastic fiber C may make it difficult to uniformly
disperse the fibers, thereby decreasing the texture and mechanical
strength as a non-woven fabric, and the crimp number is preferably
80 (crimps/25 mm) or less. Furthermore, from the viewpoint of
further improving the crimping performance and carding
process-passing, the crimp number is preferably 10 to 50 (crimps/25
mm), more preferably 10 to 30 (crimps/25 mm).
[0046] Specific examples of the thermoplastic fibers C can include
thermoplastic cellulosic fibers, acrylic fibers, nylon fibers, and
polyester fibers (polyethylene terephthalate fibers,
polytrimethylene terephthalate fibers, etc.). These may be used
alone, or two or more thereof may be used together. From the
viewpoint of crimping performance and availability, most preferred
are polyethylene terephthalate fiber (hereinafter referred to as
PET fibers). The preferred content of the thermoplastic fiber C in
the non-woven fabric is 20 to 50% by mass, more preferably 35 to
50% by mass.
[0047] The non-melting fiber A and thermoplastic fibers B, C as
described above are formed into a web such that the fibers are
mixed: for example, heat over the melting point of the
thermoplastic fibers C is supplied to melt the thermoplastic fibers
C once, and the thermoplastic fibers C is then cooled and
solidified, thereby fusing to the non-melting fiber A and the
thermoplastic fiber B and constituting a non-woven fabric
integrally. It is to be noted that for the fusion, a pressure may
be applied with the thermoplastic fiber C softened by a method of
applying such heat over the glass transition temperature of the
thermoplastic fiber C, thereby pressure-bonding the thermoplastic
fiber C, the non-melting fiber A, and the thermoplastic fiber B.
This is preferred because a higher binder effect can be
achieved.
[0048] The method for forming the web may be any method such as a
dry method or a wet method, but a dry method is preferred to
uniformly disperse various fibers, and different types of fibers
are preferably bonded with the fibers entangled with each other.
For that reason, the non-melting fiber A and the thermoplastic
fibers B and C are each preferably cut into, for example, a length
of 2 to 10 mm, and are entangled with each other. As the fiber
bonding method, any method may be applied, such as a thermal bond
method, a needle punch method, and a spun lace method, but it is
further preferable to apply a spun lace method in order to increase
the density of the non-woven fabric. Alternatively, with the
non-melting fiber A made into a web, the thermoplastic fibers B and
C may be laminated thereon by a spun bond method or a melt blown
method.
[0049] In order to improve the process-passing in the thermal bond
method and the strength of the non-woven fabric, the thermoplastic
fibers B and C preferably partially have a fiber with low
crystallinity, such as an undrawn fiber. Specifically, fibers of
the same material are more compatible with each other and strongly
fused to each other; thus, for example, as described above, with
the use of a drawn PPS fiber and an undrawn PPS fiber as the
thermoplastic fiber B, the fibers are preferably fused to enhance
the binder effect and then constitute a non-woven fabric. It is to
be noted that the mass ratio of the drawn PPS fibers to the undrawn
PPS fibers is preferably 3:1 to 1:3, more preferably 1:1.
[0050] In the non-woven fabric according to the present invention,
the density is also preferably 50 kg/m.sup.3 or less. The thermal
conductivity becomes smaller, thereby achieving excellent thermal
insulation performance. The density is more preferably 50 to 30
kg/m.sup.3, further preferably 50 to 40 kg/m.sup.3, in order to
achieve lightweight and excellent thermal insulation
performance.
[0051] In addition, the weight per unit area is preferably 50
g/m.sup.2 or more, more preferably 100 g/m.sup.2 or more in order
to further improve the flame shielding performance.
[0052] Furthermore, in order to improve the flame shielding
performance, the thickness of the non-woven fabric in accordance
with JIS L 1096-A method (2010) is also preferably 0.08 mm or
more.
EXAMPLES
[0053] <<Flammability Resistance Test>>
[0054] The test was performed in accordance with the 8.1.1 A-1
method (45.degree. micro-burner method) of JIS L 1091 (Testing
methods for flammability of textiles, 1999). More specifically, the
afterflame time (3 seconds or shorter), afterglow time (5 seconds
or lower), burnt area (30 cm.sup.2 or less), extent of combustion
(20 cm or less) after heating for 1 minute were measured, and the
afterflame time (3 seconds or shorter), afterglow time (5 seconds
or lower), burnt area (30 cm.sup.2 or less) after 3 seconds from
lighting were then measured and classified. These measurements, if
have values in the parentheses, correspond to the "Class 3" of the
evaluation category in accordance with JIS L 1091, which determines
that the flammability is graded pass.
[0055] <<Flame Shielding Performance Evaluation>>
[0056] Lighting was performed by a method in accordance with the
8.1.1 A-1 method (45.degree. micro-burner method) of JIS L 1091
(Testing methods for flammability of textiles, 1999), and the flame
shielding performance was evaluated as follows. More specifically,
as shown in the FIGURE, a micro-burner 1 of 45 mm in flame length L
was erected in the vertical direction, a specimen 2 was disposed at
an angle of 45 degrees with respect to the horizontal plane, and
the flame shielding performance was evaluated by a test of burning
a combustible 4 disposed with respect to the specimen 2 with
spacers 3 of 2 mm in thickness th interposed therebetween. With the
use of, for the combustible 4, a qualitative filter paper grade 2
(1002) sold by GE Healthcare Japan Corporation, left in the
standard state for 24 hours in advance in order to make the
moisture content uniform, the time from lighting the micro-burner 1
to flashing the combustible 4 was measured on the second time
scale. This measurement was performed 3 times, and the average
value was adopted.
[0057] The case where the combustible 4 was flashed within 3
minutes from contact with flame was regarded as "without flame
shielding performance" and listed as F. Although the case where the
combustible 4 was not flashed after exposure to the flame for 3
minutes or longer is regarded as "with flame shielding
performance", the flame shielding time is preferably longer, and
thus, the flame shielding time of 3 minutes or longer and shorter
than 20 minutes was listed B, whereas the flame shielding time of
20 minutes or longer was listed A.
[0058] <<Weight Per Unit Area>>
[0059] The measurement was performed in accordance with 8.3 (method
A) of JIS L 1096 (2010), and the weight per unit area was expressed
in mass per 1 m.sup.2 (g/m.sup.2). The measurement was performed
twice, and the average value was adopted.
[0060] <<Thickness>>
[0061] The thickness was measured in accordance with JIS L 1913
(2010) 6.1.3 (C method). The measurement was performed 10 times,
and the average value was adopted.
[0062] <<Glass Transition Temperature>>
[0063] The glass transition temperature was measured three times in
accordance with JIS K 7121 (2012), and the average value was
adopted.
[0064] <<Crimp Number>>
[0065] The measurement was performed in accordance with JIS L 1015
(2010) 8.12.1. The measurement was performed 20 times, and the
average value was adopted.
[0066] <<Fiber Used>>
[0067] <Non-Melting Fiber A-1>
[0068] 1.7 dtex flame-resistant fiber "PYRON" (registered
trademark) manufactured by Zoltek, with length: 6 mm,
high-temperature shrinkage ratio: 1.6%, and thermal conductivity:
0.033 W/mK
[0069] <Non-Melting Fiber A-2>
[0070] 1.67 dtex meta-aramid fiber with length: 6 mm,
high-temperature shrinkage ratio: 2.8%, and thermal conductivity:
0.055 W/mK
[0071] <Thermoplastic Fiber B-1>
[0072] PPS fiber (containing 35% by mass of PPS undrawn fiber in
100% by mass of PPS fiber) with length: 5.1 mm, LOI value: 34,
glass transition temperature: 90.degree. C., and crimp number: 6
(crimps/25 mm)
[0073] <Thermoplastic Fiber B-2>
[0074] PPS fiber (containing 40% by mass of PPS undrawn fiber in
100% by mass of PPS fiber) with length: 5.1 mm, LOI value: 34,
glass transition temperature: 90.degree. C., and crimp number: 6
(crimps/25 mm)
[0075] <Thermoplastic Fiber B-3>
[0076] PPS fiber (containing 33% by mass of PPS undrawn fiber in
100% by mass of PPS fiber) with length: 5.1 mm, LOI value: 34,
glass transition temperature: 90.degree. C., and crimp number: 6
(crimps/25 mm)
[0077] <Thermoplastic Fiber C-1>
[0078] PET fiber (containing 35% by mass of PET undrawn fiber in
100% by mass of PET fiber) with length: 5.1 mm, LOI value: 20,
glass transition temperature: 68.degree. C., and crimp number: 16
(crimps/25 mm)
[0079] <Thermoplastic Fiber C-2>
[0080] PET fiber (containing 33% by mass of PET undrawn fiber in
100% by mass of PET fiber) with length: 5.1 mm, LOI value: 20,
glass transition temperature: 68.degree. C., and crimp number: 16
(crimps/25 mm)
[0081] <Thermoplastic Fiber C-3>
[0082] PET fiber (containing 30% by mass of PET undrawn fiber in
100% by mass of PET fiber) with length: 5.1 mm, LOI value: 20,
glass transition temperature: 68.degree. C., and crimp number: 16
(crimps/25 mm)
[0083] <Thermoplastic Fiber C-4>
[0084] PET fiber (containing 50% by mass of PET undrawn fiber in
100% by mass of PET fiber) with length: 5.1 mm, LOI value: 20,
glass transition temperature: 68.degree. C., and crimp number: 13
(crimps/25 mm).
[0085] <Other Fiber D-1>
[0086] Acrylic fiber with length: 5.1 mm, high-temperature
shrinkage ratio: 35%, and thermal conductivity: 1.02 W/mK
[0087] <Other Fiber D-2>
[0088] Nylon fiber (containing 33% by mass of nylon undrawn fiber
in 100% by mass of nylon fiber) with length: 5.1 mm, LOI value: 21,
glass transition temperature: 58.degree. C., and crimp number: 15
(crimps/25 mm)
[0089] <Other Fiber D-3>
[0090] Flame-retardant rayon fiber with length: 5.1 mm, LOI value:
27, and crimp number: 5 (crimps/25 mm)
[0091] <Other fiber D-4>
[0092] PET fiber (containing 35% by mass of PET undrawn fiber in
100% by mass of PET fiber) with length: 5.1 mm, LOI value: 20,
glass transition temperature: 68.degree. C., and crimp number: 3
(crimps/25 mm)
Example 1
[0093] The non-melting fiber A-1, the thermoplastic fiber B-1, and
the thermoplastic fiber C-1 were mixed such that the mass ratios
met 3:4:3, and opened with a carding machine to a fiber web (weight
per unit area: 98 g/m.sup.2). The action of a needle on the fiber
web at a needle density of 40 pins/cm.sup.2 entangled the fibers to
form a combined sheet including the flame-resistant fiber, the PPS
fiber, and the PET fiber in the same non-woven fabric layer.
Subsequently, the combined sheet was subjected to a heat treatment
with a hot air dryer set at a temperature of 150.degree. C. to fuse
the flame-resistant fiber, PPS fiber, and PET fiber constituting
the sheet and form a fused combined sheet. The fused combined sheet
was washed with warm water at a temperature of 70.degree. C. for 6
seconds and then naturally dried to obtain a non-woven fabric with
the oil removed therefrom. The measured crimp number of each short
fiber taken from this non-woven fabric with tweezers was equivalent
to the crimp number of the raw material described in <<Fiber
Used>>. The mass of the non-woven fabric was 98% by mass with
respect to the raw cotton mass (yield rate).
[0094] The obtained non-woven fabric was 100 g/m.sup.2 in weight
per unit area and 50 kg/m.sup.3 in density, and was dense and soft,
even with sufficient tenseness. As the result of performing the
flammability resistance test, the combustible was not flashed even
after heating for 1 minute, and the burnt area and the extent of
combustion were respectively 10 cm.sup.2 or less and 10 cm,
indicating sufficient flame retardancy. In addition, the non-woven
fabric, which was not broken or punctured even when the non-woven
fabric was bent by 90.degree. or more, was provided with excellent
bending workability. Furthermore, without flashing the combustible
for 21 minutes in the evaluation of the flame shielding
performance, the non-woven fabric was provided with sufficient
flame shielding performance.
Example 2
[0095] The non-melting fiber A-2, the thermoplastic fiber B-1, and
the thermoplastic fiber C-1 were mixed such that the mass ratios
met 2:3:5, and opened with a carding machine to a fiber web (weight
per unit area: 130 g/m.sup.2). The action of a needle on the fiber
web at a needle density of 40 pins/cm.sup.2 entangled the fibers to
form a combined sheet including the meta-aramid fiber, the PPS
fiber, and the PET fiber in the same non-woven fabric layer.
Subsequently, the combined sheet was subjected to a heat treatment
with a hot air dryer set at a temperature of 150.degree. C. to fuse
the meta-aramid fiber, PPS fiber, and PET fiber constituting the
sheet and form a fused combined sheet. The fused combined sheet was
washed with warm water at a temperature of 70.degree. C. for 6
seconds and then naturally dried to obtain a non-woven fabric with
the oil removed therefrom. The measured crimp number of each short
fiber taken from this non-woven fabric with tweezers was equivalent
to the crimp number of the raw material described in <<Fiber
Used>>. The mass of the non-woven fabric was 97% by mass with
respect to the raw cotton mass (yield rate).
[0096] The obtained non-woven fabric was 135 g/m.sup.2 in weight
per unit area and 45 kg/m.sup.3 in density, and was dense and
provided with tenseness, with a slight lack of softness as compared
with the non-woven fabric according to Example 1. As the result of
performing the flammability resistance test, the combustible was
not flashed even after heating for 1 minute, and the burnt area and
the extent of combustion were respectively 10 cm.sup.2 or less and
12 cm, indicating sufficient flame retardancy. In addition, the
non-woven fabric, which was not broken or punctured even when the
non-woven fabric was bent by 90.degree. or more, was provided with
excellent bending workability. Furthermore, without flashing the
combustible for 15 minutes in the evaluation of the flame shielding
performance, the non-woven fabric was provided with sufficient
flame shielding performance.
Example 3
[0097] The non-melting fiber A-1, the thermoplastic fiber B-2, and
the thermoplastic fiber C-2 were mixed such that the mass ratios
met 3:3:4, and opened with a carding machine to a fiber web (weight
per unit area: 115 g/m.sup.2). The action of a needle on the fiber
web at a needle density of 40 pins/cm.sup.2 entangled the fibers to
form a combined sheet including the flame-resistant fiber, the PPS
fiber, and the PET fiber in the same non-woven fabric layer.
Subsequently, the combined sheet was subjected to a heat treatment
with a hot air dryer set at a temperature of 150.degree. C. to fuse
the flame-resistant fiber, PPS fiber, and PET fiber constituting
the sheet and form a fused combined sheet. The fused combined sheet
was washed with warm water at a temperature of 70.degree. C. for 6
seconds and then naturally dried to obtain a non-woven fabric with
the oil removed therefrom. The measured crimp number of each short
fiber taken from this non-woven fabric with tweezers was equivalent
to the crimp number of the raw material described in <<Fiber
Used>>. The mass of the non-woven fabric was 97% by mass with
respect to the raw cotton mass (yield rate).
[0098] The obtained non-woven fabric was 122.5 g/m.sup.2 in weight
per unit area and 35 kg/m.sup.3 in density, and was dense and soft,
even with sufficient tenseness. As the result of performing the
flammability resistance test, the combustible was not flashed even
after heating for 1 minute, but afterglow was observed, and the
afterglow time was 3 seconds. In addition, the burnt area and the
extent of combustion were respectively 29 cm.sup.2 or less and 11
cm, indicating sufficient flame retardancy. In addition, the
non-woven fabric, which was not broken or punctured even when the
non-woven fabric was bent by 90.degree. or more, was found to have
excellent bending workability. Furthermore, without flashing the
combustible for 15 minutes in the evaluation of the flame shielding
performance, the non-woven fabric was provided with sufficient
flame shielding performance.
Example 4
[0099] The non-melting fiber A-2, the thermoplastic fiber B-3, and
the thermoplastic fiber C-2 were mixed such that the mass ratios
met 4:1:5, and opened with a carding machine to a fiber web (weight
per unit area: 38 g/m.sup.2). The action of a needle on the fiber
web at a needle density of 40 pins/cm.sup.2 entangled the fibers to
form a combined sheet including the meta-aramid fiber, the PPS
fiber, and the PET fiber in the same non-woven fabric layer.
Subsequently, the combined sheet was subjected to a heat treatment
with a hot air dryer set at a temperature of 150.degree. C. to fuse
the meta-aramid fiber, PPS fiber, and PET fiber constituting the
sheet and form a fused combined sheet. The fused combined sheet was
washed with warm water at a temperature of 70.degree. C. for 6
seconds and then naturally dried to obtain a non-woven fabric with
the oil removed therefrom. The measured crimp number of each short
fiber taken from this non-woven fabric with tweezers was equivalent
to the crimp number of the raw material described in <<Fiber
Used>>. The mass of the non-woven fabric was 97% by mass with
respect to the raw cotton mass (yield rate).
[0100] The obtained non-woven fabric was 40 g/m.sup.2 in weight per
unit area and 40 kg/m.sup.3 in density, and was dense and soft,
even with sufficient tenseness. As the result of performing the
flammability resistance test, the combustible was not flashed even
after heating for 1 minute, but afterglow was observed, and the
afterglow time was 3 seconds. In addition, the burnt area and the
extent of combustion were respectively 27 cm.sup.2 and 18 cm,
indicating sufficient flame retardancy. In addition, the non-woven
fabric, which was not broken or punctured even when the non-woven
fabric was bent by 90.degree. or more, was found to have excellent
bending workability. Furthermore, without flashing the combustible
for 9 minutes in the evaluation of the flame shielding performance,
the non-woven fabric was provided with sufficient flame shielding
performance.
Comparative Example 1
[0101] The non-melting fiber C-3 and the other fibers D-1 and D-2
were mixed such that the mass ratios met 3:3:4, and opened with a
carding machine to a fiber web (weight per unit area: 98
g/m.sup.2). The action of a needle on the fiber web at a needle
density of 40 pins/cm.sup.2 entangled the fibers to form a combined
sheet including the acrylic fiber, the nylon fiber, and the PET
fiber in the same non-woven fabric layer. The combined sheet was
subjected to a heat treatment with a hot air dryer set at a
temperature of 150.degree. C. to fuse the acrylic fiber, nylon
fiber, and PET fiber constituting the sheet and form a fused
combined sheet. The fused combined sheet was washed with warm water
at a temperature of 70.degree. C. for 6 seconds and then naturally
dried to obtain a non-woven fabric with the oil removed therefrom.
The measured crimp number of each short fiber taken from this
non-woven fabric with tweezers was equivalent to the crimp number
of the raw material described in <<Fiber Used>>. The
mass of the non-woven fabric was 99% by mass with respect to the
raw cotton mass (yield rate).
[0102] The obtained non-woven fabric was 100 g/m.sup.2 in weight
per unit area and 50 kg/m.sup.3 in density, and was dense and soft,
even with sufficient tenseness. As the result of performing the
flammability resistance test, a hole was produced in a part
directly above the burner in shorter than 3 seconds after holding
the burner over specimen, and the specimen itself was flashed and
burned. Accordingly, the specimen is not considered to have flame
retardancy. In addition, the specimen itself was flashed and burned
as described above, and is thus considered to have no flame
shielding performance without any measurement.
Comparative Example 2
[0103] The non-melting fiber A-1, the thermoplastic fiber C-4, and
other fiber D-3 were mixed such that the mass ratios met 3:3:4, and
opened with a carding machine to a fiber web (weight per unit area:
75 g/m.sup.2). The action of a needle on the fiber web at a needle
density of 40 pins/cm.sup.2 entangled the fibers to form a combined
sheet including the flame-resistant fiber, the frame-retardant
rayon fiber, and the PET fiber in the same non-woven fabric layer.
The combined sheet was subjected to a heat treatment with a hot air
dryer set at a temperature of 150.degree. C. to fuse the
flame-resistant fiber, frame-retardant rayon fiber, and PET fiber
constituting the sheet and form a fused combined sheet. The fused
combined sheet was washed with warm water at a temperature of
70.degree. C. for 6 seconds and then naturally dried to obtain a
non-woven fabric with the oil removed therefrom. The measured crimp
number of each short fiber taken from this non-woven fabric with
tweezers was equivalent to the crimp number of the raw material
described in <<Fiber Used>>. The mass of the non-woven
fabric was 99% by mass with respect to the raw cotton mass (yield
rate).
[0104] The obtained non-woven fabric was 180 g/m.sup.2 in weight
per unit area and 40 kg/m.sup.3 in density, and was dense and soft,
even with sufficient tenseness. As the result of performing the
flammability resistance test, the combustible was not flashed even
after heating for 1 minute, and the burnt area and the extent of
combustion were respectively 15 cm.sup.2 and 8 cm, indicating
sufficient flame retardancy. In the evaluation of the flame
shielding performance, the specimen itself was flashed after 2
minutes from contact with flame, without flame shielding
performance.
Comparative Example 3
[0105] The non-melting fiber A-1 and the thermoplastic fiber B-1
were mixed such that the mass ratios met 4:6, and opened with a
carding machine to a fiber web (weight per unit area: 97
g/m.sup.2). The action of a needle on the fiber web at a needle
density of 40 pins/cm.sup.2 entangled the fibers to form a combined
sheet including the flame-resistant fiber and the PPS fiber in the
same non-woven fabric layer. The combined sheet was subjected to a
heat treatment with a hot air dryer set at a temperature of
150.degree. C. to fuse the flame-resistant fiber and PPS fiber
constituting the sheet and form a fused combined sheet. The fused
combined sheet was washed with warm water at a temperature of
70.degree. C. for 6 seconds and then naturally dried to obtain a
non-woven fabric with the oil removed therefrom. The measured crimp
number of each short fiber taken from this non-woven fabric with
tweezers was equivalent to the crimp number of the raw material
described in <<Fiber Used>>. The mass of the non-woven
fabric was 50% by mass with respect to the raw cotton mass (yield
rate).
[0106] The obtained non-woven fabric was 100 g/m.sup.2 in weight
per unit area and 50 kg/m.sup.3 in density, and was dense and soft,
even with sufficient tenseness. As the result of performing the
flammability resistance test, the combustible was not flashed even
after heating for 1 minute, and the burnt area and the extent of
combustion were respectively 5 cm.sup.2 or less and 8 cm,
indicating sufficient flame retardancy. In addition, the non-woven
fabric, which was not broken or punctured even when the non-woven
fabric was bent by 90.degree. or more, was found to have excellent
bending workability. Furthermore, without flashing the combustible
for 30 minutes in the evaluation of the flame shielding
performance, the non-woven fabric was provided with sufficient
flame shielding performance. As shown by the yield rate of 50% by
mass, however, the fibers were likely to fall from the carding
machine, and it was thus necessary to reduce the fiber speed of
passing through the carding machine.
Comparative Example 4
[0107] The non-melting fiber A-1, the thermoplastic fiber B-1, and
the other fiber D-4 were mixed such that the mass ratios met 3:4:3,
and opened with a carding machine to a fiber web (weight per unit
area: 98 g/m.sup.2). The action of a needle on the fiber web at a
needle density of 40 pins/cm.sup.2 entangled the fibers to form a
combined sheet including the flame-resistant fiber, the PPS fiber,
and the PET fiber in the same non-woven fabric layer. Subsequently,
the combined sheet was subjected to a heat treatment with a hot air
dryer set at a temperature of 150.degree. C. to fuse the
flame-resistant fiber, PPS fiber, and PET fiber constituting the
sheet and form a fused combined sheet. The fused combined sheet was
washed with warm water at a temperature of 70.degree. C. for 6
seconds and then naturally dried to obtain a non-woven fabric with
the oil removed therefrom. The measured crimp number of each short
fiber taken from this non-woven fabric with tweezers was equivalent
to the crimp number of the raw material described in <<Fiber
Used>>. The mass of the non-woven fabric was 50% by mass with
respect to the raw cotton mass (yield rate).
[0108] The obtained non-woven fabric was 100 g/m.sup.2 in weight
per unit area and 50 kg/m.sup.3 in density, and was dense and soft,
even with sufficient tenseness. As the result of performing the
flammability resistance test, the combustible was not flashed even
after heating for 1 minute, and the burnt area and the extent of
combustion were respectively 10 cm.sup.2 or less and 10 cm,
indicating sufficient flame retardancy. In addition, the non-woven
fabric, which was not broken or punctured even when the non-woven
fabric was bent by 90.degree. or more, was provided with excellent
bending workability. Furthermore, without flashing the combustible
for 21 minutes in the evaluation of the flame shielding
performance, the non-woven fabric was provided with sufficient
flame shielding performance.
[0109] Table 1 summarizes the evaluation results of Examples 1 to 4
and Comparative Examples 1 to 4.
TABLE-US-00001 TABLE 1 Example Example Example Example Comparative
Comparative Comparative Comparative 1 2 3 4 Example 1 Example 2
Example 3 Example 4 Composition Non-melting A-1 30 0 30 0 0 30 40
30 (% by mass) Fiber A (flame-resistant fiber "PYRON") A-2 0 20 0
40 0 0 0 0 (meta-aramid fiber) Thermoplastic B-1 (PPS fiber) 40 30
0 0 0 0 60 40 Fiber B B-2 (PPS fiber) 0 0 30 0 0 0 0 0 B-3 (PPS
fiber) 0 0 0 10 0 0 0 0 Thermoplastic C-1 (PET fiber) 30 50 0 0 0 0
0 0 Fiber C C-2 (PET fiber) 0 0 4 0 50 0 0 0 0 C-3 (PET fiber) 0 0
0 0 30 0 0 0 C-4 (PET fiber) 0 0 0 0 0 30 0 0 Other Fibers D-1 0 0
0 0 30 0 0 0 (acrylic fiber) D-2 0 0 0 0 40 0 0 0 (nylon fiber) D-3
0 0 0 0 0 40 0 0 (flame-retardant rayon fiber) D-4 0 0 0 0 0 0 0 30
(PET fiber) Physical weight per unit area (g/m.sup.2) 100 135 122.5
40 100 180 100 100 Properties density (kg/m.sup.3) 50 45 35 40 50
40 50 50 Performance flame retardancy pass pass pass pass fall pass
pass pass afterflame time after heating for 1 0 0 0 0 -- 0 0 0
minute (seconds) afterglow time after heating for 1 0 0 3 3 -- 0 0
0 minute (seconds) burnt area after heating for 1 <10 <10
<29 27 -- 15 <5 <10 minute (cm.sup.2) extent of combustion
after heating 10 12 11 18 -- 8 8 10 for 1 minute cm) flame
shielding performance A B B B F F A A time to flash (minutes) 21 15
15 9 -- 2 30 21 yield rate (%) 98 97 97 97 99 99 50 50
INDUSTRIAL APPLICABILITY
[0110] The present invention is effective in fire spread
prevention, suitable for use in wall materials, floor materials,
ceiling materials, and the like that require flame retardancy, and
suitable particularly for use as a fire blocking material for
furniture and bedding.
DESCRIPTION OF REFERENCE SIGNS
[0111] 1: Micro-burner [0112] 2: Specimen [0113] 3: Spacer [0114]
4: Combustible [0115] L: Flame length [0116] th: Spacer
thickness
* * * * *