U.S. patent application number 17/415877 was filed with the patent office on 2022-03-10 for napped artificial leather and composite material.
This patent application is currently assigned to KURARAY CO., LTD.. The applicant listed for this patent is KURARAY CO., LTD.. Invention is credited to Akihisa IWAMOTO, Masashi MEGURO, Kimio NAKAYAMA.
Application Number | 20220074133 17/415877 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-10 |
United States Patent
Application |
20220074133 |
Kind Code |
A1 |
NAKAYAMA; Kimio ; et
al. |
March 10, 2022 |
NAPPED ARTIFICIAL LEATHER AND COMPOSITE MATERIAL
Abstract
Disclosed is a napped artificial leather including: a
fiber-entangled body including ultrafine fibers having a fineness
of 0.5 dtex or less; and an elastic polymer impregnated into the
fiber-entangled body, the napped artificial leather having a
thickness of 0.25 to 1.5 mm, and including a main surface that is a
napped surface formed by napping the ultrafine fibers. The napped
artificial leather further includes phosphorous-based flame retard
ant particles attached to the elastic polymer such as a
polyurethane, the phosphorous-based flame retardant particles being
locally present in a range of a thickness of 200 pm or less from a
back surface opposite to the main surface. The phosphorous-based
flame retardant particles have an average particle size of 0.1 to
30 .mu.m, a phosphorus atom content of 14 mass % or more, and a
solubility in water at 30.degree. C. of 0.2 mass % or less, and a
melting point, or, in the absence of a melting point, a
decomposition temperature, of 150.degree. C. or more, and a content
ratio of the phosphorous-based flame retardant particles is 1 to 6
mass % as a content ratio in terms of phosphorus atoms.
Inventors: |
NAKAYAMA; Kimio;
(Okayama-shi, Okayama, JP) ; IWAMOTO; Akihisa;
(Okayama-shi, Okayama, JP) ; MEGURO; Masashi;
(Okayama-shi, Okayama, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KURARAY CO., LTD. |
Kurashiki-shi, Okayama |
|
JP |
|
|
Assignee: |
KURARAY CO., LTD.
Kurashiki-shi, Okayama
JP
|
Appl. No.: |
17/415877 |
Filed: |
November 28, 2019 |
PCT Filed: |
November 28, 2019 |
PCT NO: |
PCT/JP2019/046648 |
371 Date: |
June 18, 2021 |
International
Class: |
D06N 3/00 20060101
D06N003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2018 |
JP |
2018-246738 |
Dec 28, 2018 |
JP |
2018-246739 |
Claims
1. A napped artificial leather comprising: a fiber-entangled body
comprising ultrafine fibers having a fineness of 0.5 dtex or less;
an elastic polymer impregnated into the fiber-entangled body; and
phosphorous-based flame retardant particles attached to the elastic
polymer; wherein: the napped artificial leather having has a
thickness of 0.25 to 1.5 mm; the napped artificial leather
comprises including a main surface that is a napped surface formed
by napping the ultrafine fibers and a back surface opposite to the
main surface; the phosphorous-based flame retardant particles are
locally present in a range of a thickness of 200 .mu.m or less from
the back surface; the phosphorous-based flame retardant particles
have an average particle size of 0.1 to 30 .mu.m, a phosphorus atom
content of 14 mass % or more, a solubility in water at 30.degree.
C. of 0.2 mass % or less, and a melting point, or, in the absence
of a melting point, a decomposition temperature, of 150.degree. C.
or more; and a content ratio of the phosphorous-based flame
retardant particles in the napped artificial leather is 1 to 6 mass
% as a content ratio in terms of phosphorus atoms.
2. The napped artificial leather according to claim 1, wherein: the
elastic polymer comprises a polyurethane that is a reaction product
of a polyurethane raw material comprising a polymer polyol, an
organic polyisocyanate, and a chain extender; the polymer polyol
comprises 60 mass % or more of a polycarbonate polyol, and has an
average number of repeating carbon atoms excluding a reactive
functional group, of 6.5 or less; and the organic polyisocyanate
comprises at least one selected from the group consisting of
4,4'-dicyclohexylmethane diisocyanate and 4,4'-diphenylmethane
diisocyanate.
3. The napped artificial leather according to claim 1, wherein the
napped artificial leather has a basis weight of 100 to 300
g/m.sup.2.
4. The napped artificial leather according to claim 1, wherein the
phosphorous-based flame retardant particles include comprise at
least one compound selected from the group consisting of an organic
phosphinic acid metal salt, an aromatic phosphonic acid ester, and
a phosphoric acid ester amide.
5. The napped artificial leather according to claim 1, wherein the
phosphorous-based flame retardant particles comprise at least one
selected from the group consisting of a dialkyl phosphinic acid
metal salt and a monoalkyl phosphinic acid metal salt.
6. The napped artificial leather according to claim 1, wherein 90
to 100 mass % of the phosphorous-based flame retardant particles
are present in the range of a thickness of 200 .mu.m or less from
the back surface.
7. The napped artificial leather according to claim 1, wherein a
ratio of a thickness of a region of the napped artificial leather
in which the phosphorous-based flame retardant particles are
locally present to an overall thickness of the napped artificial
leather is 10 to 60%.
8. The napped artificial leather according to claim 1, wherein a
content ratio of the phosphorous-based flame retardant particles
relative to a total amount of the phosphorous-based flame retardant
particles and the elastic polymer is 5 to 20 mass % in terms of
phosphorus atoms.
9. The napped artificial leather according to claim 1, wherein: the
elastic polymer comprises a first elastic polymer that is present
throughout a thickness cross section of the napped artificial
leather, and a second elastic polymer that is locally present in
the range of a thickness of 200 um or less from the back surface;
and the phosphorous-based flame retardant particles are attached to
the second elastic polymer.
10. The napped artificial leather according to claim 9, wherein a
content ratio of the phosphorous-based flame retardant particles
relative to a total amount of the phosphorous-based flame retardant
particles and the second elastic polymer is 10 to 30 mass % in
terms of phosphorus atoms.
11. A composite material comprising: the napped artificial leather
according to claim 1; and an interior backing material bonded to
the back surface of the napped artificial leather with an
adhesive.
12. The composite material according to claim 11, wherein the
composite material has a total heat release (THR) of 10 MJ/m.sup.2
or less.
13. The composite material according to claim 11, wherein the
composite material has a peak heat release rate (PHRR) of 250
kW/m.sup.2 or less.
14. The composite material according to claim 11, wherein the
composite material has a maximum average rate of heat emission
(MARHE) of 90 kW/m.sup.2 or less.
15. The napped artificial leather according to claim 2, wherein the
phosphorous-based flame retardant particles comprise at least one
selected from the group consisting of a dialkyl phosphinic acid
metal salt and a monoalkyl phosphinic acid metal salt.
16. The napped artificial leather according to claim 6, wherein the
phosphorous-based flame retardant particles comprise at least one
selected from the group consisting of a dialkyl phosphinic acid
metal salt and a monoalkyl phosphinic acid metal salt.
17. The napped artificial leather according to claim 7, wherein the
phosphorous-based flame retardant particles comprise at least one
selected from the group consisting of a dialkyl phosphinic acid
metal salt and a monoalkyl phosphinic acid metal salt.
18. The napped artificial leather according to claim 9, wherein the
phosphorous-based flame retardant particles comprise at least one
selected from the group consisting of a dialkyl phosphinic acid
metal salt and a monoalkyl phosphinic acid metal salt.
Description
TECHNICAL FIELD
[0001] The present invention relates to a napped artificial leather
having both flame retardancy and an excellent surface quality
appearance, and a composite material using the same.
BACKGROUND ART
[0002] Conventionally, a napped artificial leather having an
appearance resembling that of a suede leather has been known that
is obtained by napping one surface of an artificial leather gray
fabric in which a fiber-entangled body such as a non-woven fabric
is impregnated with an elastic polymer. The napped artificial
leather is used for the materials of shoes, clothing, gloves, bags,
balls, and the like, and the interior materials for buildings and
vehicles. The napped artificial leather is advantageous, for
example, in that it is superior in quality stability, heat
resistance, water resistance, and abrasion resistance, and also is
easier to maintain, as compared with natural leathers such as a
suede leather.
[0003] Meanwhile, in recent years, interior materials for which
leather-like sheets such as synthetic leather sheets have been used
as the interior materials for public transports such as aircrafts,
vessels, and railroad vehicles, and the interior materials for
public buildings such as hotels and department stores. The interior
materials that are used in public places are required to have a
high level of flame retardancy such as self-extinguishing
properties, low smoke generation, and low heat generation in order
to ensure safety in the event of a fire. In order to meet such
flame retardancy requirements, halogen-based flame retardants
having high flame retardancy performance have hitherto been widely
blended in the interior materials. However, halogen-based flame
retardants generate a toxic halogen gas when burned. Therefore,
public organizations and users with environmental concerns have
recommended that halogen-based flame retardants not be used. For
instance, PTLs 1 to 4 listed below disclose techniques for using a
phosphorous-based flame retardant and a metal hydroxide-based flame
retardant in order to make leather-like sheets flame retardant.
CITATION LIST
Patent Literatures
[0004] [PTL 1] Japanese Laid-Open Patent Publication No. 56-050985
[0005] [PTL 2] Japanese Laid-Open Patent Publication No.
2009-235628 [0006] [PTL 3] Japanese Laid-Open Patent Publication
No. 2013-227685 [0007] [PTL 4] Japanese Laid-Open Patent
Publication No. 2007-321280
SUMMARY OF INVENTION
Technical Problem
[0008] A napped artificial leather obtained by impregnating an
elastic polymer into voids inside a fiber-entangled body of
ultrafine fibers having a fineness of less than 1 dtex has a smooth
surface touch and an excellent quality appearance as compared with
a napped artificial leather using a knitted or woven fabric of
fibers having a fineness of about 1 to 5 dtex, which are also
called regular fibers, as a base material. However a napped
artificial leather including ultrafine fibers has a larger fiber
surface area than that of a napped artificial leather including
regular fibers, and therefore has lower flame retardancy.
[0009] It has been difficult to impart sufficient flame retardancy
to a napped artificial leather including ultrafine fibers, without
using a halogen-based flame retardant. Examples of the
non-halogen-based flame retardant containing no halogen include a
phosphorous-based flame retardant. Specific examples of the
phosphorous-based flame retardant include polyphosphoric acid
inorganic salts such as a polyphosphoric acid metal salt, ammonium
polyphosphate, and carbamate polyphosphate, and phosphoric acid
salts such as guanidine phosphate. However, polyphosphoric acid
inorganic salts and phosphoric acid salts have relatively high
water solubility, and therefore tend to be swollen or dissolved by
moisture, water, or heat in the usage environments, or tend to
bleed to the surface of the napped artificial leather when heat
acts thereon through drying after they have been applied to the
napped artificial leather. As a result of the flame retardant being
swollen or dissolved, or bleeding to the surface of the napped
artificial leather, the flame retardant causes whitening or
coloring of the napped surface that is the main surface, thus
impairing the surface quality appearance of the napped artificial
leather. Although aromatic-containing phosphoric acid esters, and
aliphatic phosphoric acid esters such as an aliphatic phosphonic
acid ester and an aliphatic cyclic phosphonic acid ester have
relatively low water solubility, they cannot provide sufficient
effect of imparting flame retardancy, impair the texture of the
napped artificial leather, or are likely to cause bleeding or the
like.
[0010] It is an object of the present invention to provide a napped
artificial leather including a fiber-entangled body of ultrafine
fibers, wherein flame retardancy has been imparted to the napped
artificial leather by using a non-halogen-based flame retardant
without impairing the surface quality appearance, and also to
provide a composite material using the napped artificial
leather.
Solution to Problem
[0011] An aspect of the present invention is directed to a napped
artificial leather including: a fiber-entangled body including
ultrafine fibers having a fineness of 0.5 dtex or less; and an
elastic polymer impregnated into the fiber-entangled body, the
napped artificial leather having a thickness of 0.25 to 1.5 mm, and
including a main surface that is a napped surface formed by napping
the ultrafine fibers. The napped artificial leather further
includes phosphorous-based flame retardant particles attached to
the elastic polymer, the phosphorous-based flame retardant
particles being locally present in a range of a thickness of 200
.mu.m or less from a back surface opposite to the main surface.
[0012] The phosphorous-based flame retardant particles have an
average particle size of 0.1 to 30 .mu.m, preferably 0.5 to 30
.mu.phosphorus atom content of 14 mass % or more, and a solubility
in water at 30.degree. of 0.2 mass % or less, and a melting point,
or, in the absence of a melting point, a decomposition temperature,
of 150.degree. C. or more. Also, a content ratio of the
phosphorous-based flame retardant particles is 1 to 6 mass % as a
content ratio in terms of phosphorus atoms.
[0013] With such a napped artificial leather, it is possible to
obtain a napped artificial leather to which flame retardancy has
been imparted using a non-halogen-based flame retardant without
impairing the surface quality appearance, by allowing the
above-described phosphorous-based flame retardant particles to be
locally present at a high concentration in a back surface
constituting a surface opposite to a main surface that forms the
appearance of a napped artificial leather including a
fiber-entangled body of ultrafine fibers.
[0014] Preferably, the elastic polymer includes a polyurethane that
is a reaction product of a polyurethane raw material including a
polymer polyol, an organic polyisocyanate, and a chain extender,
the polymer polyol includes 60 mass % or more of a polycarbonate
polyol, and has an average number of repeating carbon atoms
excluding a reactive functional group, of 6.5 or less, and the
organic polyisocyanate includes at least one selected from the
group consisting of 4,4'-dicyclohexylmethane diisocyanate and
4,4'-diphenylmethane diisocyanate.
[0015] Preferably, the napped artificial leather has a basis weight
of 100 to 300 g/m.sup.2.
[0016] As the phosphorous-based flame retardant particles, an
organic phosphinic acid metal salt, an aromatic phosphoric acid
ester, and a phosphoric acid ester amide are particularly
preferable. In particular, it is preferable to include, as the
phosphorous-based flame retardant particles, at least one selected
from the group consisting of a dialkyl phosphinic acid metal salt
and a monoalkyl phosphinic acid metal salt, because these are
highly water resistant and heat resistant, have a high phosphorus
atom content, and achieve high flame retardancy effect.
[0017] It is preferable that in the napped artificial leather, 90
to 100 mass % of the phosphorous-based flame retardant particles
are present in the range of a thickness of 200 .mu.m or less from
the back surface of the napped artificial leather, because the
surface quality appearance is further less likely to be
impaired.
[0018] It is preferable that in the napped artificial leather, a
content ratio of the phosphorous-based flame retardant particles in
a total amount of the phosphorous-based flame retardant particles
and the elastic polymer is 5 to 20 mass % in terms of phosphorus
atoms, because the reduction in flame retardancy due to the elastic
polymer can be sufficiently suppressed.
[0019] It is preferable that in the napped artificial leather, the
elastic polymer includes the first elastic polymer that is present
throughout a thickness cross section thereof, and a second elastic
polymer that is locally present in the range of a thickness of 200
.mu.m or less, and the phosphorous-based flame retardant particles
are attached to the second elastic polymer, because the
phosphorous-based flame retardant particles are likely to be
locally present in the range of a thickness of 200 .mu.m or
less.
[0020] It is preferable that in the napped artificial leather, a
content ratio of the phosphorous-based flame retardant particles in
a total amount of the phosphorous-based flame retardant particles
and the second elastic polymer is 10 to 30 mass % in terms of
phosphorus atoms, because the effect of the second elastic polymer
on the reduction in flame retardancy is reduced.
[0021] Another aspect of the present invention is directed to
composite material obtained by bonding, to the back surface of any
one of the napped artificial leathers, an interior backing material
using an adhesive. Such a composite material has both flame
retardancy and an excellent surface quality appearance as an
interior material or an exterior material whose surface is
decorated using the napped artificial leather.
[0022] For example, the above-described composite material can
achieve a total heat release (THR) of 10 MJ/m.sup.2 or less, a peak
heat release rate (PHRR) of 250 kW/m.sup.2 or less, or a maximum
average rate of heat emission (MARHE) of 90 kW/m.sup.2 or less.
Advantageous Effects of Invention
[0023] According to the present invention, it is possible to obtain
a napped artificial leather including a fiber-entangled body of
ultrafine fibers, wherein flame retardancy is imparted to the
napped artificial leather using a non-halogen-based flame retardant
without impairing the surface quality appearance, and a composite
material using the napped artificial leather.
DESCRIPTION OF EMBODIMENT
[0024] A napped artificial leather according to the present
embodiment is a napped artificial leather including: a
fiber-entangled body including ultrafine fibers having a fineness
of 0.5 dtex or less; and an elastic polymer impregnated into the
fiber-entangled body, the napped artificial leather having a
thickness of 0.25 to 1.5 mm, and including a main surface that is a
napped surface formed by napping the ultrafine fibers. Also, the
napped artificial leather further includes phosphorous-based flame
retardant particles attached to the elastic polymer, the
phosphorous-based flame retardant particles being locally present
in a range of a thickness of 200 .mu.m or less from a back surface
opposite to the main surface.
[0025] The elastic polymer imparts shape stability to the
fiber-entangled body, and imparts a quality appearance to the
napped surface. Examples of the elastic polymer include
polyurethane, an acrylonitrile elastomer, an olefin elastomer, a
polyester elastomer, a polyamide elastomer, and an acrylic
elastomer. These may be used alone or in a combination of two or
more. Among these, polyurethane is preferable.
[0026] As the elastic polymer, it is particularly preferable to
include a polyurethane that is a reaction product of a polyurethane
raw material including a polymer polyol, an organic polyisocyanate,
and a chain extender, the polymer polyol includes 60 mass % or more
of a polycarbonate polyol, and has an average number of repeating
carbon atoms excluding a reactive functional group, of 6.5 or less,
and the organic polyisocyanate includes at least one selected from
the group consisting of 4,4'-dicyclohexylmethane diisocyanate and
4,4'-diphenylmethane diisocyanate.
[0027] The phosphorous-based flame retardant particles have an
average particle size of 0.1 to 30 .mu.m, a phosphorus atom content
of 14 mass % or more, a solubility in water at 30.degree. C. of 0.2
mass % or less, a melting point, or, in the absence of a melting
point, a decomposition temperature, of 150.degree. C. or more.
Also, the napped artificial leather contains 1 to 6 mass % of the
phosphorous-based flame retardant particles as a content ratio in
terms of phosphorus atoms.
[0028] The napped artificial leather can be obtained, for example,
by a flame retardant treatment in which a treating liquid
containing phosphorous-based flame retardant particles and a second
elastic polymer is applied to a back surface opposite to a main
surface of a napped artificial leather gray fabric including a
fiber-entangled body including ultrafine fibers having a fineness
of 0.5 dtex or less, and a first elastic polymer impregnated into
the fiber-entangled body, and including the main surface that is a
napped surface formed by napping the ultrafine fibers, and having a
thickness of 0.25 to 1.5 mm, and thereafter the napped artificial
leather gray fabric is dried, thus allowing the phosphorous-based
flame retardant particles to be locally present in the region of a
thickness of 200 .mu.m or less from the back surface.
[0029] The napped artificial leather has a basis weight of
preferably 100 to 600 g/m.sup.2, more preferably 100 to 300
g/m.sup.2, particularly preferably 170 to 300 g/m.sup.2, and quite
particularly preferably 170 to 250 g/m.sup.2, because high flame
retardancy can be sufficiently maintained, the phosphorous-based
flame retardant particles are less likely to affect the appearance
and the tactile impression of the napped surface, and the surface
quality appearance is further less likely to be reduced.
[0030] Examples of the fiber-entangled body including ultrafine
fibers having a fineness of 0.5 dtex or less include fiber
structures such as a non-woven fabric, a woven fabric, and a
knitted fabric including ultrafine fibers having a fineness of 0.5
dtex or less. Among these, a non-woven fabric of ultrafine fibers
is particularly preferable because the homogeneity is increased,
and therefore a napped artificial leather excellent in suppleness
and fullness can be obtained. In the present embodiment, a
non-woven fabric of ultrafine fibers will be described in detail as
a representative example of the fiber-entangled body of ultrafine
fibers.
[0031] Examples of the production method of the non-woven fabric of
ultrafine fibers include a production method in which
island-in-the-sea composite fibers are melt spun to produce a web,
and the web is subjected to an entangling treatment, and thereafter
the sea component is selectively removed from the island-in-the-sea
composite fibers, to form ultrafine fibers. Examples of the
production method of the web include a method in which filaments of
the island-in-the-sea composite fibers that have been spun by
spunbonding or the like are collected on a net, without being cut,
to form a filament web, and a method in which filaments are cut
into staples to form a staple web. Among these, a filament web is
particularly preferable because of excellent denseness and
excellent fullness. The formed web may be subjected to a fusion
bonding treatment in order to impart shape stability thereto.
Examples of the entangling treatment include a method in which
about 5 to 100 layers of the web are placed on top of each other,
and subjected to needle punching or a high-pressure water jetting
treatment. In any of the processes until the sea component of the
island-in-the-sea composite fibers is removed to form ultrafine
fibers, a fiber shrinking treatment such as heat shrinking using
water vapor may be performed, thus densifying the island-in-the-sea
composite fibers to enhance the fullness.
[0032] Although the present embodiment describes in detail a case
where the island-in-the-sea composite fibers are used, the
non-woven fabric may be produced using ultrafine fiber-generating
fibers other than the island-in-the-sea composite fibers, or to
directly spin ultrafine fibers without using ultrafine
fiber-generating fibers. As specific examples of the ultrafine
fiber-generating fibers other than the island-in-the-sea composite
fibers, any fibers capable of forming ultrafine fibers may be used
without any particular limitation, including: for example,
strip/division-type fibers in which a plurality of ultrafine fibers
are lightly bonded immediately after spinning, and separated by a
mechanical operation, to form a plurality of ultrafine fibers; and
petal-shaped fibers obtained by alternately assembling a plurality
of resins in a petal shape in a melt spinning process.
[0033] The island component resin of the island-in-the-sea
composite fibers for forming the ultrafine fibers is not
particularly limited. Specific examples thereof include: aromatic
polyesters such as polyethylene terephthalate (PET), isophthalic
acid-modified PET, sulfoisophthalic acid-modified PET, polybutylene
terephthalate, and polyhexamethylene terephthalate; aliphatic
polyesters such as polylactic acid, polyethylene succinate,
polybutylene succinate, polybutylene succinate adipate, and a
polyhydroxybutyrate-polyhydroxyvalerate resin; polyamides (nylons)
such as 6-polyamide, polyamide 66, polyamide 10, polyamide 11,
polyamide 12, and polyamide 6-12; and polyolefins such as
polypropylene, polyethylene, polybutene, polymethylpentene, and a
chlorine-based polyolefin. These may be used alone or in a
combination of two or more. Among these, PET or modified PET,
polylactic acid, polyamide 6, polyamide 12, polyamide 6-12,
polypropylene, and the like are preferable.
[0034] As the sea component resin for forming the island-in-the-sea
composite fibers, a resin that differs from the island component
resin in solubility in a solvent or in decomposability in a
decomposition agent is selected. Specific examples of the
thermoplastic resin for forming the sea component include a
water-soluble polyvinyl alcohol, polyethylene, polypropylene,
polystyrene, an ethylene-propylene resin, an ethylene-vinyl acetate
resin, a styrene-ethylene resin, and a styrene-acrylic resin.
[0035] The sea component of the island-in-the-sea composite fibers
is removed by dissolution or decomposition at an appropriate stage
after the web has been formed. Through such removal by
decomposition or through dissolution and extraction, the
island-in-the-sea composite fibers are subjected to ultrafine fiber
generation, and ultrafine fibers in the form of fiber bundles are
formed.
[0036] The fineness of the ultrafine fibers is 0.5 dtex or less,
preferably 0.001 to 0.4 dtex, and more preferably 0.01 to 0.3 dtex.
When the fineness of the ultrafine fibers exceeds 0.5 dtex, the
quality appearance of the napped surface is likely to be reduced.
As for the fineness, a cross section of the napped artificial
leather in the thicknesses direction is imaged using a scanning
electron microscope (SEM) at a magnification of 2000.times., to
obtain a cross-sectional area of single fibers, and the fineness of
a single fiber can be calculated from the cross-sectional area and
the specific gravity of the resin that forms the ultrafine fibers.
The fineness can be defined as an average value of the fineness of
average 100 single fibers, evenly obtained from the captured
image.
[0037] The first elastic polymer is evenly applied into the entire
non-woven fabric. The first elastic polymer restrains ultrafine
fibers, thus imparting shape stability to the fiber-entangled body
including ultrafine fibers having a fineness of 0.5 dtex or less,
and providing a quality appearance to the napped surface. Examples
of the first elastic polymer include polyurethane, an acrylonitrile
elastomer, an olefin elastomer, a polyester elastomer, a polyamide
elastomer, and an acrylic elastomer. These may be used alone or in
a combination of two or more. Among these, polyurethane is
preferable.
[0038] Note that polyurethane tends to be more flammable than
ultrafine fibers. In the napped artificial leather according to the
present embodiment, the deterioration in appearance of the napped
surface due to application of a flame retardant can be suppressed
by applying the flame retardant to the back surface side of the
napped artificial leather.
[0039] In the case of using polyurethane, it is particularly
preferable to use a specific polyurethane because the flame
retardancy of the napped surface can be improved.
[0040] Such a specific polyurethane includes a polyurethane that is
a reaction product of a polyurethane raw material including a
polymer polyol, an organic polyisocyanate, and a chain extender,
the polymer polyol includes 60 mass % or more of a polycarbonate
polyol, and has an average number of repeating carbon atoms
excluding a reactive functional group, of 6.5 or less, and the
organic polyisocyanate includes at least one selected from the
group consisting of 4,4'-dicyclohexylmethane diisocyanate and
4,4'-diphenylmethane diisocyanate. Such a polyurethane is excellent
in self-extinguishing properties, has reduced heat release and
smoke generation, and exhibits a high level of flame
retardancy.
[0041] Specific examples of the polycarbonate polyol include
polycarbonate polyols such as polyhexamethylene carbonate diol,
poly(3-methyl-1,5-pentylene carbonate) diol, polypentamethylene
carbonate diol, polytetramethylene carbonate diol, and
polycyclohexane carbonate diol, and copolymers thereof.
[0042] The polymer polyol may include a polymer polyol other than
the polycarbonate polyol in a range that does not exceed 40 mass %
of the polymer polyol. Specific examples of the polymer polyol
other than the polycarbonate polyol include polyether polyols such
as polyethylene glycol, polypropylene glycol, polytetramethylene
glycol, and poly(methyl tetramethylene glycol), and copolymers
thereof; polyester polyols such as polyethylene adipate diol,
poly(l,2-propylene adipate)diol, poly(l,3-propylene adipate)diol,
polybutylene adipate diol, polybutylene sebacate diol,
polyhexamethylene adipate diol, poly(3-methyl-1,5-pentane
adipate)diol, poly(3-methyl-1,5-pentane sebacate)diol, and
polycaprolactone diol, and copolymers thereof; polycarbonate
polyols having 6.5 or more carbon atoms; and polyester carbonate
polyols. These may be used alone or in a combination of two or
more.
[0043] The content ratio of the polycarbonate polyol included in
the polymer polyol used for production of the specific polyurethane
is 60 mass % or more, and is preferably 70 mass % or more. When the
content ratio of the polycarbonate polyol included in the polymer
polyol is less than 60 mass %, the heat release and the smoke
generation of the polyurethane increase.
[0044] The average number of repeating carbon atoms excluding a
reactive functional group, of the polymer polyol used for
production of the specific polyurethane is 6.5 or less, and is
preferably 6.0 or less. When the average number of repeating carbon
atoms excluding a reactive functional groups, of the polymer polyol
exceeds 6.5, the hear release and the smoke generation of the
polyurethane also increase.
[0045] Here, the average number of repeating carbon atoms excluding
a reactive functional group, of the polymer polyol is defined as
the number of carbon atoms in a hydrocarbon included in the
repeating units of the polymer polyol, including a carbonate group
(--OCOO--), an ester group (--COO--), an ether group (--O--), or
the like in a reaction for forming the polymer polyol, excluding a
reactive functional group. The average number of repeating carbon
atoms excluding a reactive functional group in the case where two
or more polymer polyols are used is a value obtained by calculating
the average value of the number of carbon atoms in a hydrocarbon
included in the repeating units of the two or more polymer polyols
including carbonate groups, ester groups, ether groups, or the
like, excluding a reactive functional group.
[0046] As the molecular weight of the polymer polyol, the polymer
polyol has an average molecular weight of preferably 200 to 6000,
and more preferably 500 to 5000.
[0047] The organic polyisocyanate used for production of the
specific polyurethane includes at least one selected from the group
consisting of 4,4'-dicyclohexylmethane diisocyanate and
4,4'-diphenylmethane diisocyanate. Preferably 60 mass % or more,
more preferably 70 mass % or more, and particularly preferably 80
mass % or more of the organic polyisocyanate includes at least one
selected from the group consisting of 4,4'-dicyclohexylmethane
diisocyanate and 4,4'-diphenylmethane diisocyanate, because a
polyurethane exhibiting excellent self-extinguishing properties and
having reduced heat release and smoke generation can be
obtained.
[0048] For the polyurethane raw material, a multifunctional alcohol
such as a trifunctional alcohol and a tetrafunctional alcohol, and
a short-chain alcohol such as ethylene glycol may be used in
addition to the polymer polyol. These may be used alone or in a
combination of two or more.
[0049] For the polyurethane raw material, another organic
isocyanate may also be used in addition to 4,4'-dicyclohexylmethane
diisocyanate and 4,4'-diphenylmethane diisocyanate. Specific
examples of such an organic isocyanate include non-yellowing
diisocyanates, including, for example, aliphatic or alicyclic
diisocyanates such as hexamethylene diisocyanate, isophorone
diisocyanate, and norbornene diisocyanate; and aromatic
diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene
diisocyanate, and xylylene diisocyanate polyurethane. If necessary,
a multifunctional isocyanate such as a trifunctional isocyanate or
a tetrafunctional isocyanate, and a blocked multifunctional
isocyanate may also be used. These may be used alone or in a
combination of two or more.
[0050] As the chain extender used for production of the specific
polyurethane, a low-molecular weight compound having two or more
active hydrogens can be used. Specific examples of the chain
extender include diamines such as hydrazine, ethylene diamine,
propylene diamine, hexamethylene diamine, nonamethylene diamine,
xylylene diamine, isophorone diamine, piperazine and derivatives
thereof, adipic acid dihydrazide, and isophthalic acid dihydrazide;
triamines such as diethylenetriamine; tetramines such as
triethylene tetramine; diols such as ethylene glycol, propylene
glycol, 1,4-butane diol, 1,6-hexane diol,
1,4-bis(.beta.-hydroxyethoxy)benzene, and 1,4-cyclohexane diol;
triols such as trimethylol propane; pentaols such as
pentaerythritol; amino alcohols such as amino ethyl alcohol and
amino propyl alcohol. These may be used alone or in a combination
of two or more. Among these, it is preferable to use a combination
of two or more from hydrazine, piperazine, ethylenediamine,
hexamethylene diamine, isophoronediamine, and derivatives thereof,
triamine such as diethylenetriamine, and ethylene glycol, propylene
glycol, 1,4-butane diol, and derivatives thereof, because of the
excellent mechanical properties. Monoamines such as ethylamine,
propylamine, and butylamine; carboxyl group-containing monoamine
compounds such as 4-amino butanoic acid and 6-amino hexanoic acid;
monools such as methanol, ethanol, propanol, and butanol may be
used together with the chain extender during a chain extending
reaction. Among these, a chain extender having six or less carbon
atoms excluding a reactive functional group is particularly
preferable because of the excellent self-extinguishing properties
and the reduced heat release and smoke generation.
[0051] In order to control the water absorption ratio, the adhesion
with ultrafine fibers, and the hardness of polyurethane, a
crosslinked structure may be formed in the polyurethane by adding a
crosslinking agent containing, in the molecule, two or more
functional groups capable of reacting with a functional group
included in monomer units that form the polyurethane, such as a
carbodiimide-based compound, an epoxy-based compound, an
oxazoline-based compound, or a self-crosslinking compound such as a
polyisocyanate-based compound and a multifunctional block
isocyanate compound.
[0052] Examples of the emulsion of the polyurethane include a
forcedly emulsified polyurethane emulsion that does not include any
ionic group in the polyurethane skeleton and has been emulsified by
adding an emulsifier; a self-emulsified polyurethane emulsion that
includes an ionic group such as a carboxyl group, a sulfonic acid
group, and an ammonium group in the polyurethane skeleton and has
been emulsified by self-emulsification; and a polyurethane emulsion
that uses an emulsifier and an ionic group in the polyurethane
skeleton in combination. Examples of the method for introducing a
carboxyl group into the polyurethane skeleton include a method in
which units of carboxyl group-containing diols such as
2,2-bis(hydroxymethyl)propionic acid,
2,2-bis(hydroxymethyl)butanoic acid, and
2,2-bis(hydroxymethyl)valeric acid are incorporated into the
polyurethane skeleton.
[0053] The first elastic polymer is applied to the fiber-entangled
body, for example, by impregnating a fiber-entangled body of
ultrafine fibers-generating fibers such as island-in-the-sea
composite fibers for forming ultrafine fibers, or a fiber-entangled
body of ultrafine fibers with an emulsion of an elastic polymer
such as a polyurethane emulsion or a solution of an elastic polymer
such as a polyurethane solution, followed by coagulation. Examples
of the method for impregnating the fiber-entangled body with the
emulsion or solution of the first elastic polymer include methods
using a knife coater, a bar coater, or a roll coater, and a method
involving dipping. In the case of using an emulsion, the elastic
polymer can be coagulated by a method in which heating is performed
in a drying device at 50 to 200.degree. C., a method in which
heating is performed in a dryer after infrared heating, a method in
which heating is performed in a dryer after a steam treatment, a
method in which heating is performed in a dryer after ultrasonic
heating, or a combination of these methods.
[0054] As the emulsion of the polyurethane, it is preferable to use
a self-emulsified polyurethane and a forcedly emulsified
polyurethane in combination, and it is preferable to use a
polyurethane emulsion including, for example, 20 to 100 mass % of a
self-emulsified polyurethane and 0 to 80 mass % of a forcedly
emulsified polyurethane, because a flexible texture can be
achieved. The average dispersed particle size of the emulsion of
the polyurethane is preferably 0.01 to 1 .mu.m, and more preferably
0.03 to 0.5 .mu.m.
[0055] When the fiber-entangled body is impregnated with the
emulsion of the polyurethane, and thereafter dried, the emulsion
may migrate to the surface layer of the fiber-entangled body, and
may thus become less likely to be uniformly applied in the
thickness direction. In such a case, for example, it is possible to
suppress the migration in the following manner. Adjusting the
dispersed particle size of the emulsion; adjusting the type and the
amount of the ionic group in the polyurethane; reducing the water
dispersion stability by addition of an ammonium salt that undergoes
a pH change at a temperature of about 40 to 100.degree. C.; or
reducing the water dispersion stability by addition of a monovalent
or divalent alkali metal salt or alkaline-earth metal salt, a
nonionic emulsifier, an associative water-soluble thickener, an
associative heat-sensitive gelling agent such as a water-soluble
silicone-based compound, or a water-soluble polyurethane-based
compound.
[0056] The first elastic polymer has a 100% modulus of preferably
0.5 to 7 MPa, and more preferably 1 to 5 MPa, because a flexible
texture can be obtained, and smooth surface and surface physical
properties can be imparted. When the 100% modulus is too low, the
first elastic polymer is softened to restrain the ultrafine fibers
when the napped artificial leather is subjected to heat, so that
the flexible texture and the smooth surface touch tends to be
reduced. When the 100% modulus is too high, the smooth surface
touch of the napped artificial leather tends to be reduced, and the
texture may be hard.
[0057] The ratio of the first elastic polymer included in the
napped artificial leather is preferably 3 to 50 mass %, more
preferably 3 to 40 mass %, particularly preferably 3 to 35 mass %,
and quite particularly preferably, 7 to 25 mass %, in terms of the
well-balanced high flame retardancy, surface quality appearance,
shape stability, and surface physical properties.
[0058] The fiber-entangled body containing the first elastic
polymer is subjected to a heat-moisture shrinking treatment or
pressed as needed so that the apparent density, the basis weight,
or the thickness thereof is adjusted, and thus is finished into an
artificial leather gray fabric. Then, the artificial leather gray
fabric is sliced as needed. Then, at least one surface of the
artificial leather gray fabric is buffed using a contact buff or an
emery buff, thus producing a napped artificial leather gray fabric
including a napped surface.
[0059] It is preferable that the buffing is performed using
sandpaper or emery paper with a grit number of about 120 to 600,
for example. By raising the fibers on the surface that has been
buffed in this manner, a napped artificial leather gray fabric
including a napped surface formed by napping the ultrafine fibers
is produced. The napped artificial leather gray fabric may be
further subjected to a finishing treatment such as a dyeing
treatment, a flexibilizing treatment by crumpling, a softening
treatment by milling, a reverse seal brushing treatment, an
antifouling treatment, a hydrophilization treatment, a lubricant
treatment, a softener treatment, an antioxidant treatment, an
ultraviolet absorber treatment, and a fluorescent agent treatment,
as needed.
[0060] The thickness of the napped artificial leather gray fabric
is substantially equal to the thickness of the resulting final
napped artificial leather. The thickness of the napped artificial
leather gray fabric is 0.25 to 1.5 mm, preferably 0.3 to 1.0 mm,
and more preferably 0.4 to 1.0 mm. When the thickness of the napped
artificial leather gray fabric exceeds 1.5 mm, sufficient flame
retardancy effect is less likely to be achieved.
[0061] The napped artificial leather can be obtained by a flame
retardant treatment, which is a treatment in which a treating
liquid containing phosphorous-based flame retardant particles and a
second elastic polymer is applied to a back surface opposite to the
napped surface that is a main surface of the napped artificial
leather gray fabric having a thickness of 0.25 to 1.5 mm, and
thereafter dried, thus allowing the phosphorous-based flame
retardant particles to be locally present in a range of a thickness
of 200 .mu.m or less from the back surface.
[0062] Here, allowing the phosphorous-based flame retardant
particles to be locally present in a range of a thickness of 200
.mu.m or less from a back surface opposite to the main surface in
the napped artificial leather means that the majority of the
phosphorous-based flame retardant particles present in the napped
artificial leather, specifically, 90 to 100 mass %, more
particularly 95 to 100 mass %, of the phosphorous-based flame
retardant particles are present in the range of a thickness of 200
.mu.m or less from the back surface opposite to the main surface.
The thickness from the back surface in which the phosphorous-based
flame retardant particles are locally present, opposite to the main
surface is preferably 50 to 200 .mu.m, more preferably 70 to 180
.mu.m, and particularly preferably 100 to 150 .mu.m. The thickness
of the region of the napped artificial leather in which the
phosphorous-based flame retardant particles are locally present can
be confirmed by observing a cross section of the napped artificial
leather that is parallel to the thickness direction thereof using a
scanning electron microscope. The ratio of the thickness of the
region in which the phosphorous-based flame retardant particles are
locally present to the overall thickness of the napped artificial
leather is preferably 10 to 60%, and more preferably 10 to 50%,
because a high level of flame retardancy can be easily imparted
using a non-halogen-based flame retardant without impairing the
surface quality appearance.
[0063] In this manner, by allowing the phosphorous-based flame
retardant particles to be locally present in the range of a
thickness of 200 .mu.m or less from the back surface of the napped
artificial leather such that the content ratio in terms of
phosphorus atoms is 1 to 6 mass %, it is possible to impart flame
retardancy using a non-halogen-based flame retardant without
impairing the surface quality appearance.
[0064] The content ratio, in the napped artificial leather, of the
phosphorous-based flame retardant particles locally present in the
range of a thickness of 200 .mu.m or less from the back surface of
the napped artificial leather is 1 to 6 mass %, and preferably 1.5
to 5.5 mass %, in terms of phosphorus atoms. When the content ratio
of the phosphorous-based flame retardant particles in terms of
phosphorus atoms is less than 1 mass %, a high level of flame
retardancy is less likely to be achieved. When the content ratio of
the phosphorous-based flame retardant particles in terms of
phosphorus atoms exceeds 6 mass %, it is difficult to allow the
phosphorous-based flame retardant particles to be locally present
in the range of a thickness of 200 .mu.m or less from the back
surface by fixing the phosphorous-based flame retardant particles
without causing them to fall off. Additionally, the suppleness of
the napped artificial leather may be lost, or the surface quality
appearance thereof may be reduced.
[0065] The phosphorous-based flame retardant particles included in
the napped artificial leather are particles of a flame retardant
compound that contains phosphorus atoms, and is a particulate solid
at room temperature, the flame retardant compound having an average
particle size of 0.1 to 30 .mu.m, a phosphorus atom content of 14
mass % or more, a solubility in water at 30.degree. C. of 0.2 mass
% or less, a melting point, or, in the absence of a melting point,
a decomposition temperature, of 150.degree. C. or more.
[0066] The average particle size of the phosphorous-based flame
retardant particles is 0.1 to 30 .mu.m, preferably 0.5 to 30 .mu.m,
more preferably 0.5 to 15 .mu.m, and particularly preferably 1 to
10 .mu.m. When the average particle size exceeds 30 .mu.m, the
phosphorous-based flame retardant particles are less likely to be
sufficiently infiltrated in the range of a thickness of 200 .mu.m
or less from the back surface of the napped artificial leather such
that the content ratio of the phosphorous-based flame retardant
particles is 1 to 6 mass % as a content ratio in terms of
phosphorus atoms, so that the flame retardancy effect tends to be
insufficient. When the average particle size is less than 0.1
.mu.m, the particles are likely to aggregate and thus are unevenly
dispersed, so that the flame retardancy is likely to be
nonuniform.
[0067] The phosphorus atom content of the phosphorous-based flame
retardant particles is 14 mass % or more, preferably 15 mass % or
more, and more preferably 20 mass % or more. Also, the phosphorus
atom content is preferably 30 mass % or less, and more preferably
28 mass % or less. When the phosphorus atom content of the
phosphorous-based flame retardant particles is less than 14 mass %,
a high level of flame retardancy is less likely to be imparted.
When the phosphorus atom content of the phosphorous-based flame
retardant particles is too high, the flame retardant is likely to
fall off to be attached to the surface, and tends to adversely
affect the surface appearance and the fastness.
[0068] The phosphorous-based flame retardant particles have a
solubility in water at 30.degree. C. of 0.2 mass % or less, and is
preferably 0.15 mass % or less. When the phosphorous-based flame
retardant particles having a solubility in water at 30.degree. C.
exceeding 0.2 mass % are used, the phosphorous-based flame
retardant particles are likely to absorb moisture during production
or in use, or bleed to the napped surface when wetted with water.
Note that the solubility in water at 30.degree. C. of the
phosphorous-based flame retardant particles can be measured by
adding the phosphorous-based flame retardant particles in small
portions to 100 g of water at 30.degree. C., and measuring a
maximum mass of the phosphorous-based flame retardant particles
that can be dissolved.
[0069] The phosphorous-based flame retardant particles have a
hot-water solubility in hot water at 90.degree. C. of preferably 5
mass % or less, and more preferably 3 mass % or less, because the
flame retardant is less likely to bleed to the napped surface when
the flame retardant comes into contact with hot water during
production or in use of the napped artificial leather, and the
dimensional change of the napped artificial leather caused by the
flame retardant absorbing moisture can be suppressed. Note that the
hot-water solubility in hot water at 90.degree. C. of the
phosphorous-based flame retardant particles can be measured by
adding the phosphorous-based flame retardant particles in small
portions to 100 g of water at 90.degree. C., and measuring a
maximum mass of the phosphorous-based flame retardant particles
that can be dissolved.
[0070] The phosphorous-based flame retardant particles are
particulate solids at room temperature that have a melting point,
or, in the absence of a melting point, a decomposition temperature,
of 150.degree. C. or more, and preferably 200.degree. C. or more.
When the melting point, or, in the absence of a melting point, the
decomposition temperature is less than 150.degree. C., it is
difficult to maintain the particulate form due to softening of the
flame retardant in a drying process performed after application of
the flame retardant during the production of the napped artificial
leather. As a result, the phosphorous-based flame retardant
particles bundle up the ultrafine fibers, resulting in a reduction
in the surface touch and the texture of the napped surface. In
addition, the napped artificial leather is likely to form a molten
drop when burnt, thus making it difficult to maintain a high level
of flame retardancy.
[0071] Here, the melting point of the phosphorous-based flame
retardant particles can be specified by a melting peak temperature
as determined by thermogravimetry-differential thermal analysis
(TG-DTA), or differential scanning calorimetry (DSC). The
decomposition temperature in the absence of a melting point can be
specified by a decomposition starting temperature as determined by
thermogravimetry-differential thermal analysis (TG-DTA). Although
the measurement conditions are not particularly limited,
measurement is performed at a temperature rising rate of 5 to
10.degree. C./min under a nitrogen atmosphere.
[0072] Examples of the phosphorous-based flame retardant particles
include organic phosphinic acid metal salts such as a dialkyl
phosphinic acid metal salt and a monoalkyl phosphinic acid metal
salt; aromatic phosphonic acid esters; and phosphoric acid ester
amides. These may be used alone or in a combination of two or more.
Among these, a dialkyl phosphinic acid metal salt or a monoalkyl
phosphinic acid metal salt is preferable in that they are highly
water resistant and heat resistant, have a high phosphorus atom
content, and achieve high flame retardancy effect.
[0073] The second elastic polymer used for fixing the
phosphorous-based flame retardant particles included in the napped
artificial leather may be the same as, or different from the first
elastic polymer. Among these, polyurethane is preferable because of
the well-balanced physical properties.
[0074] The second elastic polymer has a 100% modulus of preferably
0.5 to 5 MPa, and more preferably 1 to 4 MPa, because a flexible
texture can be achieved, and detachment of the flame retardant can
be suppressed.
[0075] There is no particular limitation on the method for applying
the treating liquid containing the phosphorous-based flame
retardant particles and the second elastic polymer to the back
surface of the napped artificial leather gray fabric having a
thickness of 0.25 to 1.5 mm. Specific examples thereof include
methods involving applying the treating liquid containing the
phosphorous-based flame retardant particles and the second elastic
polymer to the back surface of the napped artificial leather gray
fabric by gravure coating, direct coating, roll coating, or spray
coating while adjusting the application amount or the
viscosity.
[0076] The viscosity of the treating liquid containing the
phosphorous-based flame retardant particles and the second elastic
polymer is preferably 200 to 10000 mPasec, and more preferably 500
to 5000 mPasec, because the phosphorous-based flame retardant
particles and the second elastic polymer are likely to be allowed
to sink moderately from the back surface of the napped artificial
leather gray fabric so as to be locally present in the range of a
thickness of 200 .mu.m or less, thus making it possible to impart
high flame retardancy to the napped artificial leather without
impairing the quality appearance of the napped surface that is the
main surface.
[0077] As the treating liquid containing the second elastic
polymer, it is preferable to use, for example, a treating liquid
prepared by dispersing the phosphorous-based flame retardant
particles in a polyurethane emulsion. In the case of using a
polyurethane emulsion, the average particle size of the emulsion is
preferably 10 .mu.m or less, and more preferably 5 .mu.m. The
drying temperature of the treating liquid is preferably 100 to
160.degree. C.
[0078] The content ratio of the phosphorous-based flame retardant
particles in the total amount of the phosphorous-based flame
retardant particles and the second elastic polymer is preferably 10
to 30 mass %, more preferably 12 to 30 mass %, and particularly
preferably 15 to 25 mass %, in terms of phosphorus atoms. It is
preferable that the content ratio of the phosphorous-based flame
retardant particles in the total amount of the phosphorous-based
flame retardant particles and the second elastic polymer is the
above-described ration, because the effect of burning of the second
elastic polymer on the reduction in flame retardancy is
reduced.
[0079] The content ratio of the phosphorous-based flame retardant
particles in the total amount of the phosphorous-based flame
retardant particles and the second elastic polymer is preferably in
the range of 10 to 30 mass % in terms of phosphorus atoms, and is
preferably 60 to 90 mass %, and more preferably 70 to 85 mass %, as
the mass of the phosphorous-based flame retardant particles.
[0080] The ratio of the second elastic polymer included in the
napped artificial leather is not particularly limited, but is
preferably 2 to 15 mass %, and more preferably 4 to 10 mass %,
because it is possible to sufficiently fix the phosphorous-based
flame retardant particles while suppressing the reduction in flame
retardancy due to application of the second elastic polymer.
[0081] When the ultrafine fibers form fiber bundles derived from
island-in-the-sea composite fibers, the elastic polymer may be
impregnated inside the fiber bundles, or may be attached to the
outside of the fiber bundles. When island-in-the-sea composite
fibers are subjected to an ultrafine fiber-generating treatment,
the thermoplastic resin serving as the sea component is removed
from the island-in-the-sea composite fibers, to form voids inside
the ultrafine fiber bundles. Therefore, the second elastic polymer
that is applied after subjecting the island-in-the-sea composite
fibers to the ultrafine fibers-generating treatment is likely to be
impregnated inside the fiber bundles to restrain the ultrafine
fibers that form the fiber bundles. Accordingly, the second elastic
polymer impregnated inside the ultrafine fiber bundles restrains
the ultrafine fiber bundle, thus contributing to improvement of the
shape retainability of the fiber-entangled body.
[0082] The ratio of the total amount of the elastic polymer
including the first elastic polymer and the second elastic polymer
included in the napped artificial leather is preferably 2 to 40
mass %, and more preferably 5 to 35 mass %, because it is possible
to reduce the effect of burning of the polyurethane on the
reduction of the flame retardancy.
[0083] The content ratio of the phosphorous-based flame retardant
particles in the total amount of the phosphorous-based flame
retardant particles and the elastic polymer including the first
elastic polymer and the second elastic polymer is preferably 5 to
20 mass %, and more preferably 6 to 20 mass %, in terms of
phosphorus atoms, because this provides a good balance between the
flame retardancy and the suppleness of the napped artificial
leather.
[0084] The total basis weight of the elastic polymer including the
first elastic polymer and the second elastic polymer contained in
the napped artificial leather is preferably 10 to 150 g/m.sup.2,
more preferably 10 to 100 g/m.sup.2, and particularly preferably 10
to 50 g/m.sup.2, because a napped artificial leather particularly
well-balanced between the self-extinguishing properties and the
surface quality appearance can be obtained.
[0085] The napped artificial leather may be subjected to softening
for the purpose of smoothing the surface touch while improving the
surface smoothness. Examples of softening include a method in which
the napped artificial leather is brought into close contact with an
elastic sheet and mechanically shrunk in a vertical direction (MD
on production line), and then heated in the shrunk state for heat
setting.
[0086] The thickness of the napped artificial leather is 0.25 to
1.5 mm, preferably 0.3 to 1.0 mm, and more preferably 0.4 to 1.0
mm. When the thickness of the napped artificial leather is less
than 0.25 mm, the flame retardant is likely to be exposed on the
surface, resulting in a reduction in the surface quality and the
surface touch. When the thickness of the napped artificial leather
exceeds 1.5 mm, the flame retardancy is reduced.
[0087] The apparent density of the napped artificial leather is
preferably 0.25 to 0.75 g/cm.sup.3, and more preferably 0.35 to
0.65 g/cm.sup.3, because this increases the fiber density of the
surface, provides favorable napped feel and surface touch of the
napped surface, and well-balanced fullness and flexible
texture.
[0088] The napped artificial leather can also be suitably used, for
example, as a wall covering material formed by attaching the napped
artificial leather and an interior backing material (back board)
together using an adhesive for composites. Specific examples of the
interior backing material include concrete, brick, a clay tile, a
ceramic tile, a fiber-reinforced cemented board, a glass fiber
cemented board, a calcium silicate board, steel, aluminum, a metal
plate, glass, mortar, plaster, stone, a plaster board, rock wool, a
glass wool board, a cemented excelsior board, a hard cemented
excelsior board, a cemented excelsior board, a pulp cemented board,
and flame-retardant plywood. Among these, concrete, brick, a clay
tile, a ceramic tile, a fiber-reinforced cemented board, a glass
fiber cemented board, a calcium silicate board, steel, aluminum, a
metal plate, and glass are preferable because they can suppress the
flammability when combined with the napped artificial leather.
[0089] Examples of the adhesive for composites include a
starch-based adhesive, an (alkyl)cellulose-based adhesive, a vinyl
acetate-based adhesive, an ethylene vinyl acetate-based adhesive,
an acrylic resin-based adhesive, a polyurethane-based adhesive, a
chloroprene-based adhesive, a phenol-based adhesive, a
nitrile-based adhesive, an ester-based adhesive, a silicone-based
adhesive, a fluorine-based adhesive, and copolymers and mixtures
thereof, or adhesives in which a metal compound such as a metal
salt or a hydroxide is mixed. Among these, a starch-based adhesive,
an (alkyl)cellulose-based adhesive, a vinyl acetate-based adhesive,
a chloroprene-based adhesive, a phenol-based adhesive, a
nitrile-based adhesive, a fluorine-based adhesive, a silicone-based
adhesive, and copolymers and mixtures thereof, and adhesives in
which a metal salt or a hydroxide is mixed are preferable, because
they can suppress the flammability when combined with the napped
artificial leather.
[0090] The flame retardancy of a composite material obtained by
bonding an interior backing material to the back surface of the
napped artificial leather using an adhesive can be evaluated using
a cone calorimeter in accordance with ISO 5660-1. Examples of the
flame retardancy evaluated by a burn test using the cone
calorimeter include a total heat release (THR; MJ/m.sup.2) due to
combustion, a peak heat rate of release (PHRR; kW/m.sup.2) per unit
area and unit time due to combustion, and a maximum average rate of
heat emission (MARHE; kW/m.sup.2).
[0091] The composite material obtained by bonding an interior
backing material to the back surface of the napped artificial
leather using an adhesive makes it possible to realize a composite
material having a total heat release (THR) of 10 MJ/m.sup.2 or
less, and even 8 MJ/m.sup.2 or less. The composite material
according to the present embodiment makes it possible to realize a
composite material having a peak heat release rate (PHRR) of 250
kW/m.sup.2 or less, and even 200 kW/m.sup.2 or less. The composite
material according to the present embodiment makes it possible to
realize a composite material having a maximum average rate of heat
emission (MARHE; kW/m.sup.2) of 90 kW/m.sup.2 or less.
[0092] The napped artificial leather has a combination of a high
level of flame retardancy, a surface quality appearance, a flexible
texture, and fullness, and therefore can be suitably used in
applications for which a high level of flame retardancy such as
self-extinguishing properties, low heat generation, and low smoke
generation is required, including, for example, the materials of
seats and sofas or the interior materials of walls and the like of
public transports such as aircrafts, vessels, railroad vehicles,
and vehicles, or public buildings such as hotels and department
stores.
EXAMPLES
[0093] Hereinafter, the present invention will be described more
specifically by way of examples. It should be appreciated that the
scope of the present invention is by no means limited by the
examples.
[0094] First, the evaluation methods used in the present examples
will be summarized.
(Surface Quality Appearance)
[0095] The napped surface of the napped artificial leather was
touched, and evaluated according to the following criteria.
[0096] A: The surface touch was smooth, and also had no rough
tactile impression caused by the phosphorous-based flame retardant
particles.
[0097] B: The surface touch was rough, and was inferior in quality
appearance.
[0098] C: The surface had a hard texture, and was inferior in
quality appearance.
[0099] D: The phosphorous-based flame retardant particles had bled
during storage, resulting in whitening of the surface.
(Thickness, Basis Weight, Apparent Density)
[0100] The thickness (mm) and the basis weight (g/cm.sup.2) of the
napped artificial leather were measured in accordance with JIS L
1913, and the apparent density (g/cm.sup.3) was calculated by
dividing the basis weight by the thickness, and converting the
value into an apparent density.
(Measurement of Thickness of Region in Which Phosphorous-Based
Flame Retardant Particles Attached to Elastic Polymer are Locally
Present)
[0101] The napped artificial leather was cut out in the thickness
direction, ten points were evenly selected from the entire cross
section in the thickness direction, and the thickness of the region
in which the phosphorous-based flame retardant particles were
present from the back surface was measured at each of the ten
points using a scanning electron microscope at a magnification of
100.times.. Then, an average value of the thicknesses at eight
points, excluding a maximum value and a minimum value, was
determined as the thickness in which the phosphorous-based flame
retardant particles were locally present.
(Average Particle Size of Phosphorous-Based Flame Retardant
Particles)
[0102] The napped artificial leather was cut out in the thickness
direction, ten points were evenly selected from the entire cross
section in the thickness direction, the region in which the
phosphorous-based flame retardant particles were present from the
back surface was selected using a scanning electron microscope at a
magnification of 1000.times., and the diameters of ten particles
were measured. Then, an average value of the particle sizes of
eight particles, excluding a maximum value and a minimum value, was
determined as the average particle size of the phosphorous-based
flame retardant particles.
(Vertical Burn Test: Self-Extinguishing Properties)
[0103] The napped artificial leather was subjected to a measurement
of the vertical flame retardancy in accordance with the burn test
standard for U.S. aircraft interior materials, prescribed in FAR
25, Appendix F, Part 1(a) (1) (ii). Specifically, the napped
artificial leather was cut to a size of 50.8 mm.times.304.8 mm, to
form a test piece. Then, the test piece was perpendicularly fixed
to a sample holder of a burn test apparatus. A burner was disposed
directly below an end of the test piece, and the flame was brought
into contact with the test piece for 12 seconds, and thereafter the
burn distance, the self-extinguishing time, the drop
self-extinguishing time of the test piece were measured. An average
for n=10 was calculated.
(Horizontal Burn Test)
[0104] The napped artificial leather was subjected to a horizontal
burn test in accordance with the burn test prescribed in FMVSS 302.
Specifically, the napped artificial leather was cut into 102
mm.times.356 mm, and a marked line was drawn at 38 mm from one end
of the resulting sample, to form a test piece. Then, the test piece
was fixed horizontally to a sample holder of a burn test apparatus.
A burner was disposed at the sample end of the test piece sample on
which the marked line was drawn, and the flame was brought into
contact with the test piece for 15 seconds. Thereafter, the burn
distance and the burn time of the test piece were measured. An
average for n=10 was calculated. The test piece was evaluated as
self-extinguished-before-marked line (SE) if the test piece had
self-extinguished before the flame reached the marked line,
evaluated as self-extinguished if the flame had passed the marked
line and the test piece had a burn distance of 50 mm or less and a
burn time of 60 seconds or less, evaluated as slow-burning if the
test piece had a burn rate of 100 ram/min or less, and evaluated as
flammable if the test piece had a burn rate of 100 ram/min or
more.
<Evaluation of Composite Material Obtained by Making Napped
Artificial Leather Composite>
[0105] A composite material obtained by making the napped
artificial leather composite was evaluated according to the
following evaluation methods.
(Combustion Heat Release Test)
[0106] As an interior material for wall covering, a composite
material was produced by bonding the napped artificial leather to a
calcium silicate board having a thickness of 11 mm and a density of
870 kg/m.sup.3 using a starch-vinyl acetate-based adhesive (solid
content: 65 g/m2). This composite material was heated/burned for 20
minutes using a heater at 50 kW/m.sup.2 in accordance with the cone
calorimeter method prescribed in ISO 5660-1, and the total heat
release (THR) after 20 minutes, the peak heat release rate (PHRR),
the time for which the peak heat value exceeded 200 kW, and the
maximum average rate of heat emission (MARHE) were measured.
(Combustion Smoke Test)
[0107] As an interior material for wall covering, a composite
material was produced by bonding the napped artificial leather to a
calcium silicate board having a thickness of 11 mm and a density of
870 kg/m.sup.3 using a starch-vinyl acetate-based adhesive (solid
content: 65 g/m.sup.2). This composite material was heated/burned
for 20 minutes using a heater at 50 kW/m.sup.2 in accordance with
the cone calorimeter method prescribed in ISO 5660-1, and the smoke
production rate (SPR) was measured.
Example 1
[0108] Island-in-the-sea composite fibers were melt spun using a
water-soluble thermoplastic polyvinyl alcohol (PVA) as a sea
component resin, and an isophthalic acid-modified polyethylene
terephthalate as an island component resin. Specifically, the
molten resin of each of the sea component resin and the island
component resin was supplied to a multicomponent fiber spinning
spinneret having nozzle holes disposed for forming a cross section
on which 25 island component resin portions were distributed in the
sea component resin, and molten fibers of the island-in-the-sea
composite fibers were discharged from the nozzle holes. At this
time, the molten resins were supplied while adjusting the pressure
such that the mass ratio between the sea component and the island
components satisfied Sea component/Island component =25/75.
[0109] Then, the molten fibers of the island-in-the-sea composite
fibers were stretched by suction using a suction apparatus, thus
spinning island-in-the-sea composite fibers having a fineness of
3.3 dtex. The spun island-in-the-sea composite fibers were
continuously piled on a movable net, and then lightly pressed with
a heated metal roll, to suppress the fuzzing on the surface. Then,
the island-in-the-sea composite fibers were removed from the net,
and thereafter allowed to pass between the metal roll and a back
roll, to hot press the fibers, thus obtaining a web having a basis
weight of 31 g/m.sup.2.
[0110] Next, the web was laid in eight layers using a cross lapper
apparatus so as to have a total basis weight of 300 g/m.sup.2, and
then needle-punched alternately from both sides thereof, to
entangle the web. The basis weight of the entangled web, which was
the needle-punched web, was 440 g/m.sup.2.
[0111] Then, the entangled web was allowed to undergo heat-moisture
shrinking for 30 seconds at 70.degree. C. and a humidity of 50% RH.
The area shrinkage before and after the heat-moisture shrinking
treatment was 47%.
[0112] Then, the shrunk entangled web was impregnated with an
emulsion of a first polyurethane (first elastic polymer) including
ammonium sulfate as a gelling agent, and thereafter dried. The
first polyurethane was a self-emulsified amorphous polycarbonate
urethane that had a 100% modulus of 3.0 MPa, and that was a
reaction product of a polymer polyol including 100% of a
polycarbonate polyol and having an average number of repeating
carbon atoms excluding a reactive functional group, of 6, an
organic polyisocyanate, which was 4,4'-dicyclohexylmethane
diisocyanate, and a chain extender.
[0113] Then, the entangled web to which the first polyurethane had
been applied was immersed in hot water to remove the PVA by
dissolution, thus forming an artificial leather gray fabric
including a non-woven fabric in which fiber bundles each including
25 ultrafine fibers having a fineness of 0.1 dtex were
three-dimensionally entangled. The first polyurethane content of
the artificial leather gray fabric was 12 mass %.
[0114] Then, the artificial leather gray fabric was sliced into
halves in the thickness direction, and the surface opposite to the
sliced surface was buffed, thus finishing the gray fabric into a
napped artificial leather gray fabric including a suede-like napped
surface. The napped artificial leather gray fabric had a thickness
of 0.5 mm, a basis weight of 250 g/m2, and an apparent density of
0.50 g/cm.sup.3.
[0115] Then, the napped artificial leather gray fabric was dyed
using a circular dyeing machine, and dried, and, thereafter, was
impregnated with a softener, and further dried.
[0116] Then, using a gravure coating machine including a 35-mesh
gravure roll, a second polyurethane emulsion of 2000 mPasec in
which particles of a dialkyl phosphinic acid metal salt serving as
a phosphorous-based flame retardant were dispersed was applied at
110 g/m.sup.2 to the sliced surface of the dyed nappe artificial
leather gray fabric, and the moisture was dried at 120.degree. C.
Note that the dialkyl phosphinic acid metal salt particles had a
dispersed particle size (median diameter: D.sub.50) of 4 .mu.m, as
measured by a laser diffraction/scattering particle size
distribution measurement apparatus, a phosphorus atom content of
23.5 mass %, a solubility in water at 30.degree. C. of less than
0.2 mass %, and a melting point and a decomposition temperature
exceeding 250.degree. C.
[0117] The second polyurethane emulsion contained 10 mass % of the
second polyurethane (second elastic polymer) and 28 mass % of the
dialkyl phosphinic acid metal salt. The second polyurethane was a
forcedly emulsified amorphous polycarbonate urethane that had a
100% modulus of 1.0 MPa, and that was a reaction product of a
polymer polyol including 100% of a polycarbonate polyol and having
an average number of repeating carbon atoms excluding a reactive
functional group, of 5.5, an organic polyisocyanate, which was
4,4'-dicyclohexylmethane diisocyanate, and a chain extender.
[0118] Then, the napped artificial leather gray fabric that had
been subjected to the flame retardant treatment was shrunk in the
vertical direction (length direction) by 5.0% by being subjected to
a shrinkage processing treatment at a drum temperature 120.degree.
C. and a transport speed of 10 m/min, and thereafter the surface
thereof was subjected to a sealing treatment, thus obtaining a
napped artificial leather including a suede-like napped surface.
The napped artificial leather had a thickness of 0.52 mm, a basis
weight of 290 g/m.sup.2, and an apparent density of 0.56
g/cm.sup.3.
[0119] The napped artificial leather contained 10 mass % of the
first polyurethane, 5 mass % of the second polyurethane, and 15
mass % of the dialkyl phosphinic acid metal salt particles. As a
result, the napped artificial leather contained 2.6 mass % of the
dialkyl phosphinic acid metal salt as a content ratio in terms of
phosphorus atoms. The mass % in terms of phosphorus atoms to the
total amount of the dialkyl phosphinic acid metal salt particles,
the first polyurethane, and the second polyurethane was 10.3 mass
%. The mass % in terms of phosphorus atoms to the total amount of
the second polyurethane and the dialkyl phosphinic acid metal salt
particles was 17.3 mass %.
[0120] Then, the obtained napped artificial leather was evaluated
according to the following evaluation methods.
[0121] The results of the above evaluation are shown in Table 1
below.
TABLE-US-00001 TABLE 1 Example No. 1 2 3 4 5 6 7 8 9 10 11
Ultrafine Fineness 0.1 0.1 0.1 0.1 0.4 0.2 0.2 0.4 0.001 0.1 0.1
fibers (dtex) Resin PET PET PET PET PET PET PET PET Ny PET PET
First Average 6 6 6 6 4.9 6 6 4.9 4.9 6 5 poly- number of urethane
repeating carbon atoms of polymer polyol Ratio of 100 100 100 100
60 100 100 75 75 100 0 polycarbon- ate in polymer polyol (mass %)
Diiso- H-MDI H-MDI H-MDI H-MDI MDI H-MDI H-MDI MDI/H- MDI H-MDI
IPDI cyanate MDI component* Content 10 9 19 11 10 10 9 20 31 10 19
ratio (C) (mass %) Second Content 5 11 5 3 5 4 4 3 5 5 5 poly-
ratio (D) urethane (mass %) Total basis weight 42 55 78 37 39 42 38
98 102 11.3 62 of first polyurethane and second poly- urethane
(g/m.sup.2) Phos- Compound Dialkyl Dialkyl Dialkyl Dialkyl
Monoalkyl Aromatic Phos- Dialkyl Dialkyl Dialkyl Dialkyl phorous-
phos- phos- phos- phos- phos- phos- phor- phos- phos- phos- phos-
based phin- phin- phin- phin- phin- phin- ic acid phin- phin- phin-
phin- flame ic acid ic acid ic acid ic acid ic acid ic acid ester
ic acid ic ester ic acid ic acid retardant metal metal metal metal
metal ester amide metal metal metal metal particles salt salt salt
salt salt salt salt salt salt Content 15 14 13 9 15 15 17 7 14 15 9
ratio (E) (mass %) Dispersed 4 4 4 4 0.5 5 20 4 4 4 4 particle size
(D.sub.50: .mu.m) Water <0.2% <0.2% <0.2% <0.2%
<0.1% <0.1% <0.1% <0.1% <0.1% <0.2% <0.2%
solubility (%: 30.degree. C.) Melting >250.degree.
>250.degree. >250.degree. C. >250.degree. >250.degree.
C. >250.degree. C. >250.degree. >250.degree.
>250.degree. C. >250.degree. >250.degree. C. point, or C.
C. C. C. C. C. decom- position temper- ature in the absence of
melting point (.degree. C.) Phosphorus 23.5 23.5 23.5 23.5 28 15 17
23.5 23.5 23.5 23.5 atom content (mass %) (F) Content ratio of 17.3
13.2 17.3 17.3 21.8 11.1 14 17.3 17.3 17.3 17.3 phosphorus atoms of
phosphorous-based flame retardant particles in total amount of
phosphorous-based flame retardant particles and second elastic
polymer ((E) * (F)/((D) + (E))) (mass %) Content ratio of 10.3 8.6
6.9 7.8 12.6 6.6 8.6 5.8 5.6 6.0 7.6 phosphorus atoms of
phosphorous-based flame retardant particles in total amount of
phosphorous-based flame retardant particles, first elastic polymer,
and second elastic polymer ((E) * (F)/ ((C) + (D) + (E)) (mass %)
Content ratio in terms 2.6 2.5 2.4 1.6 3.1 1.6 2.2 1.7 2.7 1.0 1.5
of phosphorus atoms (E) * (F)/100 (mass %) Phosphorous- 4 4 4 4 0.5
5 20 4 4 4 4 based flame retardant average particle size (SEM:
.mu.m) Thickness from back 150 150 120 180 100 180 80 150 180 150
150 surface in which phosphorous-based flame retardant particles
and second elastic polymer are present (L: .mu.m) Thickness of
napped 0.52 0.53 0.54 0.51 0.5 0.5 0.53 0.75 0.65 1.3 0.52
artificial leather (T: mm) Ratio of thickness L to 29 28 22 35 20
36 15 20 28 12 29 thickness T (%) Basis weight (g/m.sup.2) 290 300
320 275 280 280 300 435 280 725 290 Apparent density 0.56 0.56 0.59
0.54 0.56 0.56 0.57 0.58 0.43 0.56 0.56 (g/cm.sup.3) Surface
quality A A A A A A A A A A A appearance Vertical Burn 100 115 105
105 90 110 110 80 110 120 230 burn test distance (self- (mm) extin-
Self- 1 3 2.5 1 1 1 2 3.5 1 6 28 guishing extin- proper- guishing
ties) time (sec) Drop self- 0 0 0 0 0 0 0 0 0 1.0 26 extin-
guishing time (sec) Horizon- Burn rate SE SE SE SE SE SE SE SE SE
SE Slow- tal burn burning test *H-MDI_4,4'-dicyclohexylmethane
diisocyanate MDI_4,4'-diphenylmethane diisocyanate IPDI_isophorone
diisocyanate
Example 2
[0122] A napped artificial leather was obtained in the same manner
as in Example 1 except that a second polyurethane emulsion
containing 22 mass % of the second polyurethane and 28 mass % of
the dialkyl phosphinic acid metal salt was used in place of the
second polyurethane emulsion containing 10 mass % of the second
polyurethane and 28 mass % of the dialkyl phosphinic acid metal
salt, and the obtained napped artificial leather was evaluated. The
results are shown in Table 1.
Example 3
[0123] A napped artificial leather was obtained in the same manner
as in Example 1 except that an artificial leather gray fabric
having a first polyurethane content of 24 mass % was used in place
of the artificial leather gray fabric having a first polyurethane
content of 12 mass %, and the obtained napped artificial leather
was evaluated. The results are shown in Table 1.
Example 4
[0124] A napped artificial leather was obtained in the same manner
as in Example 1 except that the second polyurethane emulsion in
which the dialkyl phosphinic acid metal salt particles serving as
the phosphorous-based flame retardant were dispersed was applied at
60 g/m.sup.2, instead of being applied at 110 g/m.sup.2, and the
obtained napped artificial leather was evaluated. The results are
shown in Table 1.
Example 5
[0125] In Example 1, a non-woven fabric in which fiber bundles each
including 6 ultrafine fibers of 0.4 dtex were three-dimensionally
entangled was formed in place of the non-woven fabric in which
fiber bundles each including 25 ultrafine fibers of 0.1 dtex were
three-dimensionally entangled. In addition, as the first
polyurethane, a self-emulsified amorphous polycarbonate urethane
was used that had a 100% modulus of 3.0 MPa, and that was a
reaction product of a polymer polyol having a mass ratio between an
amorphous polycarbonate (average number of repeating carbon atoms
excluding a reactive functional group: 5.5) and a polyether polyol
(average number of repeating carbon atoms excluding a reactive
functional group: 4) of 60/40 and an average number of repeating
carbon atoms excluding a reactive functional group, of 4.9, an
organic polyisocyanate, which was 4,4'-diphenylmethane
diisocyanate, and a chain extender. Furthermore, the monoalkyl
phosphinic acid metal salt shown in Table 1 was used in place of
the dialkyl phosphinic acid metal salt as the phosphorous-based
flame retardant particles. Otherwise, a napped artificial leather
was obtained in the same manner as in Example 1, and the obtained
napped artificial leather was evaluated. The results are shown in
Table 1.
Example 6
[0126] In Example 1, a non-woven fabric in which fiber bundles each
including ultrafine fibers of 0.2 dtex were three-dimensionally
entangled was formed in place of the non-woven fabric in which
fiber bundles each including 25 ultrafine fibers of 0.1 dtex were
three-dimensionally entangled. In addition, the aromatic phosphoric
acid ester shown in Table 1 was used in place of the dialkyl
phosphinic acid metal salt as the phosphorous-based flame retardant
particles. Otherwise, a napped artificial leather was obtained in
the same manner, and the obtained napped artificial leather was
evaluated. The results are shown in Table 1.
Example 7
[0127] In Example 1, a non-woven fabric in which fiber bundles each
including ultrafine fibers of 0.2 dtex were three-dimensionally
entangled was formed in place of the non-woven fabric in which
fiber bundles each including 25 ultrafine fibers of 0.1 dtex were
three-dimensionally entangled. In addition, the phosphoric acid
ester amide shown in Table 1 was used in place of the dialkyl
phosphinic acid metal salt as the phosphorous-based flame retardant
particles. Otherwise, a napped artificial leather was obtained in
the same manner, and the obtained napped artificial leather was
evaluated. The results are shown in Table 1.
Example 8
[0128] Island-in-the-sea composite fibers were melt spun using
polyethylene as a sea component resin, and an isophthalic
acid-modified polyethylene terephthalate as an island component
resin. Specifically, the molten resin of each of the sea component
resin and the island component resin was supplied to a
multicomponent fiber spinning spinneret having nozzle holes
disposed for forming a cross section on which 25 island component
resin portions were distributed in the sea component resin, and
molten fibers of the island-in-the-sea composite fibers were
discharged from the nozzle holes. At this time, the molten resins
were supplied while adjusting the pressure such that the mass ratio
between the sea component and the island components satisfied Sea
component/Island component =25/75.
[0129] Then, the molten fibers of the island-in-the-sea composite
fibers were stretched by suction using a suction apparatus, thus
spinning island-in-the-sea composite fibers. The spun
island-in-the-sea composite fibers were continuously piled on a
movable net, and then lightly pressed with a heated metal roll, to
suppress the fuzzing on the surface. Then, the island-in-the-sea
composite fibers were removed from the net, and thereafter allowed
to pass between the metal roll and a back roll, to hot press the
fibers, thus obtaining a web.
[0130] Next, the web was laid in eight layers using a cross lapper
apparatus so as to have a total basis weight of 320 g/m.sup.2, and
then needle-punched alternately from both sides thereof, to
entangle the web. Then, the entangled web was allowed to undergo
heat-moisture shrinking for 30 seconds at 70.degree. C. and a
humidity of 50% RH.
[0131] Then, the shrunk entangled web was impregnated with an
N,N-dimethylformamide solution of the first polyurethane, and
thereafter immersed in a liquid mixture of N,N-dimethylformamide
and water for coagulation. Thereafter, the polyethylene was
extracted with toluene, and dried. Note that the first polyurethane
was an amorphous polycarbonate urethane that had a 100% modulus of
5.0 MPa, and that was a reaction product of a polymer polyol having
a mass ratio between a polycarbonate polyol (average number of
repeating carbon atoms excluding a reactive functional group: 6)
and a polyester polyol (average number of repeating carbon atoms
excluding a reactive functional group: 4) of 75/25, and having an
average number of repeating carbon atoms excluding a reactive
functional group, of 4.9, an organic polyisocyanate, which was
4,4'-diphenylmethane diisocyanate, and a chain extender.
[0132] Otherwise, a napped artificial leather was obtained in the
same manner as in Example 1, and the obtained napped artificial
leather was evaluated. The results are shown in Table 1.
Example 9
[0133] Island-in-the-sea composite fibers were melt spun using
polyethylene as a sea component resin, and 6-nylon (6-polyamide) as
an island component resin. Specifically, polyethylene and 6-nylon
were mixed at a mass ratio of 50/50, and molten, and the molten
resins were supplied to a blend spinning spinneret, and discharged
from the nozzle holes. The average number of islands of the
resulting fibers was approximately 600, and the fibers were
stretched, to give fibers of 5.5 dtex. The fibers were crimped, and
thereafter cut into 51 mm and carded, thus obtaining a staple web
having a basis weight of 100 g/m.sup.2. This web was laid in six
layers using a cross lapper apparatus, to form a superposed web,
and an oil solution was sprayed thereto, and thereafter the web was
needle punched at a density of 1500 punch/cm2, followed by hot
pressing, to obtain a fiber-entangled body having an apparent
density of 0.40 g/cm.sup.3 and a thickness of 1.5 mm.
[0134] Then, the fiber-entangled body was impregnated with an
N,N-dimethylformamide solution of the first polyurethane, and
thereafter immersed in a liquid mixture of N,N-dimethylformamide
and water for coagulation. Thereafter, the polyethylene was
extracted with toluene, and dried. Note that the first polyurethane
was a polyurethane that had a 100% modulus of 5.0 MPa, and that was
a reaction product of a polymer polyol having a mass ratio between
a polycarbonate polyol (average number of repeating carbon atoms
excluding a reactive functional group: 6) and a polyester polyol
(average number of repeating carbon atoms excluding a reactive
functional group: 4) of 75/25, and having an average number of
repeating carbon atoms excluding a reactive functional group, of
4.9, an organic polyisocyanate, which was 4,4'-diphenylmethane
diisocyanate, and a chain extender. Otherwise, a napped artificial
leather was obtained in the same manner as in Example 1 except that
the dye was changed from the disperse dye to a metal complexed dye,
and the obtained napped artificial leather was evaluated. The
results are shown in Table 1.
Example 10
[0135] A napped artificial leather was obtained in the same manner
as in Example 1 except that an artificial leather gray fabric
having a thickness of 1.3 mm was used, and the obtained napped
artificial leather was evaluated. The results are shown in Table
1.
Example 11
[0136] A napped artificial leather was obtained in the same manner
as in Example 3 except that the first elastic polymer was changed
to a polyether-based polyurethane (average number of repeating
carbon atoms excluding a reactive functional group: 5), and that
the content ratio (E) of the phosphorous-based flame retardant
particles was changed from 13 mass % to 9 mass %, and the obtained
napped artificial leather was evaluated. The results are shown in
Table 1.
Comparative Example 1
[0137] A napped artificial leather was obtained in the same manner
as in Example 1 except that a second polyurethane emulsion
containing 10 mass % of the second polyurethane and 6.8 mass % of
the dialkyl phosphinic acid metal salt was used in place of the
second polyurethane emulsion containing 10 mass % of the second
polyurethane and 28 mass % of the dialkyl phosphinic acid metal
salt, and the obtained napped artificial leather was evaluated.
Note that the viscosity of the aqueous dispersion including the
phosphorous-based flame retardant particles and the second
polyurethane was 100 mPasec. The results are shown in Table 2.
TABLE-US-00002 TABLE 2 Comparative Example No. 1 2 3 4 5 Ultrafine
Fineness (dtex) 0.1 0.1 0.1 0.1 0.6 fibers Resin PET PET PET PET
PET First Average number of repeating 6 6 6 6 9 polyurethane carbon
atoms of polymer polyol Ratio of polycarbonate in 100 100 100 100
100 polymer polyol (mass %) Diisocyanate component* H-MDI H-MDI
H-MDI H-MDI HD Content ratio (C) (mass %) 11 10 10 10 19 Second
Content ratio (D) (mass %) 6 0 5 5 5 polyurethane Total basis
weight of first polyurethane and 33 22 33 33 62 second polyurethane
(g/m.sup.2) Phosphorous- Compound Dialkyl Ammonium Ammonium
Aromatic Dialkyl based flame phosphinic polyphosphate polyphosphate
phosphoric phosphinic retardant acid acid acid particles metal salt
ester metal salt Content ratio (E) (mass %) 4 15 15 15 9 Dispersed
particle size (D.sub.50: .mu.m) 4 20 20 0.5 4 Water solubility (%:
30.degree. C.) <0.2% 0.5 0.5 <0.2% <0.2% Melting point, or
>250.degree. C. >250.degree. C. >250.degree. C.
115.degree. C. >250.degree. C. decomposition temperature in the
absence of melting point (.degree. C.) Phosphorus atom content 23.5
31 31 10 23.5 (mass %) (F) Content ratio of phosphorus atoms of 9.5
31 22.8 7.4 17.3 phosphorous-based flame retardant particles in
total amount of phosphorous-based flame retardant particles and
second elastic polymer ((E) * (F)/((D) + (E))) (mass %) Content
ratio of phosphorus atoms of 3.7 16 13.5 4.4 7.8 phosphorous-based
flame retardant particles in total amount of phosphorous-based
flame retardant particles, first elastic polymer, and second
elastic polymer ((E) * (F)/((C) + (D) + (E))) (mass %) Content
ratio in terms of phosphorus atoms 0.7 3.5 3.4 1.1 1.6 (E) *
(F)/100 (mass %) Phosphorous-based flame retardant average 4 20 20
Non- 4 particle size (SEM: .mu.m) particulate Thickness from back
surface in which 300 100 100 200 150 phosphorous-based flame
retardant particles and second elastic polymer are present (L:
.mu.m) Thickness of napped artificial leather (T: mm) 0.52 0.51
0.52 0.5 0.52 Ratio of thickness L to thickness T (%) 58 20 19 40
29 Basis weight (g/m.sup.2) 260 270 290 280 290 Apparent density
(g/cm.sup.3) 0.5 0.53 0.56 0.56 0.56 Surface quality appearance B
B, D C, D C A Vertical burn Burn distance (mm) 260 120 150 280 280
test (self- Self-extinguishing 30 9 11 40 40 extinguishing time
(sec) properties) Drop self- 8 0 4 20 30 extinguishing time (sec)
Horizontal Burn rate Slow- Self- Self- Slow- Slow- burn test
burning extinguished extinguished burning burning
*H-MDI_4,4'-dicyclohexylmethane diisocyanate
MDI_4,4'-diphenylmethane diisocyanate HD_1,6-hexamethylene
diisocyanate
Comparative Example 2
[0138] A napped artificial leather was obtained in the same manner
as in Example 1 except that an aqueous dispersion containing 28
mass % of ammonium polyphosphate was used in place of the second
polyurethane emulsion containing 10 mass % of the second
polyurethane and 28 mass % of the dialkyl phosphinic acid metal
salt, and the obtained napped artificial leather was evaluated. The
results are shown in Table 2.
Comparative Example 3
[0139] A napped artificial leather was obtained in the same manner
as in Example 1 except that the ammonium polyphosphate shown in
Table 2 was used in place of the dialkyl phosphinic acid metal salt
as the phosphorous-based flame retardant particles, and the
obtained napped artificial leather was evaluated. The results are
shown in Table 2.
Comparative Example 4
[0140] A napped artificial leather was obtained in the same manner
as in Example 1 except that the aromatic phosphoric acid ester
shown in Table 2 was used in place of the dialkyl phosphinic acid
metal salt as the phosphorous-based flame retardant particles, and
the obtained napped artificial leather was evaluated. The results
are shown in Table 2. Note that the phosphorous-based flame
retardant was treated in the form of an aqueous dispersion during
the flame retardant treatment. However, as a result of observation
of the napped artificial leather, the phosphorous-based flame
retardant had formed a resin film, and was not in the particulate
form.
Comparative Example 5
[0141] A napped artificial leather was obtained in the same manner
as in Example 4 except that ultrafine fibers having an average
fineness of 0.6 dtex produced by changing the number of the island
components formed with the spinneret from 25 to 4, and that the
first elastic polymer was changed to a polycarbonate-based
polyurethane (average number of repeating carbon atoms excluding a
reactive functional group: 9), and the obtained napped artificial
leather was evaluated. The results are shown in Table 2.
[0142] Referring to Tables 1 and 2, all of the napped artificial
leathers obtained in Examples 1 to 11 had favorable surface quality
appearance, a flexible texture, and flame retardancy. Furthermore,
the napped artificial leathers obtained in Example 1 to 10 had
favorable self-extinguishing properties, reduced smoke generation
and combustion heat release, and a very high level of flame
retardancy. On the other hand, in the case of the napped artificial
leather obtained in Comparative Example 1, which included a smaller
amount of the phosphorous-based flame retardant particles, and in
which the flame retardant particles were present even in the
interior, the phosphorous-based flame retardant was exposed on the
surface, resulting in deterioration in the surface quality
appearance. In the case of the napped artificial leather obtained
in Comparative Example 2, which used ammonium polyphosphate as the
phosphorous-based flame retardant particles, bleeding had occurred
over time, resulting in deterioration in the surface quality
appearance. In the case of the napped artificial leather obtained
in Comparative Example 3, bleeding had occurred over time,
resulting in deterioration in the surface quality appearance.
Comparative Example 4, in which the phosphorous-based flame
retardant particles were changed to the aromatic phosphoric acid
ester, had a hard texture.
Example 12
[0143] Island-in-the-sea composite fibers were melt spun using PVA
as a sea component resin, and an isophthalic acid-modified
polyethylene terephthalate as an island component resin.
Specifically, the molten resin of each of the sea component resin
and the island component resin was supplied to a multicomponent
fiber spinning spinneret having nozzle holes disposed for forming a
cross section on which 25 island component resin portions were
distributed in the sea component resin, and molten fibers of the
island-in-the-sea composite fibers were discharged from the nozzle
holes. At this time, the molten resins were supplied while
adjusting the pressure such that the mass ratio between the sea
component and the island components satisfied Sea component/Island
component =25/75.
[0144] Then, molten fibers of the island-in-the-sea composite
fibers were stretched by suction using a suction apparatus, thus
spinning island-in-the-sea composite fibers having a fineness of
3.3 dtex. The spun island-in-the-sea composite fibers were
continuously piled on a movable net, and then lightly pressed with
a heated metal roll, to suppress the fuzzing on the surface. Then,
the island-in-the-sea composite fibers were removed from the net,
and thereafter allowed to pass between the metal roll and a back
roll, to hot press the fibers, thus obtaining a web having a basis
weight of 31 g/m2.
[0145] Next, the web was laid in eight layers using a cross lapper
apparatus so as to have a total basis weight of 250 g/m.sup.2, and
then needle punched alternately from both sides thereof, to
entangle the web. The basis weight of the entangled web, which was
the needle punched web, was 350 g/m.sup.2.
[0146] Then, the entangled web was allowed to undergo heat-moisture
shrinking for 30 seconds at 70.degree. C. and a humidity of 50% RH.
The area shrinkage before and after the heat-moisture shrinking
treatment was 47%.
[0147] Then, the shrunk entangled web was impregnated with an
emulsion of a first polyurethane including ammonium sulfate as a
gelling agent, and thereafter dried. The first polyurethane was a
self-emulsified amorphous polycarbonate urethane having a 100%
modulus of 3.0 MPa and including 4,4'-dicyclohexylmethane
diisocyanate as the diisocyanate component.
[0148] Then, the entangled web to which the first polyurethane had
been applied was immersed in hot water to remove the PVA by
dissolution, thus forming an artificial leather gray fabric
including a non-woven fabric in which fiber bundles each including
25 ultrafine fibers having a fineness of 0.1 dtex were
three-dimensionally entangled. The first polyurethane content of
the artificial leather gray fabric was 12 mass %.
[0149] Then, the artificial leather gray fabric was sliced into
halves in the thickness direction, and the surface opposite to the
sliced surface was buffed, thus finishing the gray fabric into a
napped artificial leather gray fabric including a suede-like napped
surface. The napped artificial leather gray fabric had a thickness
of 0.35 mm, a basis weight of 175 g/m.sup.2, and an apparent
density of 0.50 g/cm.sup.3.
[0150] Then, the napped artificial leather gray fabric was dyed
using a circular dyeing machine, and dried, and, thereafter, was
impregnated with a softener, and further dried.
[0151] Then, using a gravure coating machine including a 35-mesh
gravure roll, a second polyurethane emulsion of 2000 mPasec in
which particles of a dialkyl phosphinic acid metal salt serving as
a phosphorous-based flame retardant were dispersed was applied at
110 g/m.sup.2 to the sliced surface of the dyed nappe artificial
leather gray fabric, and the moisture was dried at 120.degree. C.
Note that the dialkyl phosphinic acid metal salt particles had a
dispersed particle size (median diameter: D.sub.50) of 4 .mu.m, as
measured by a laser diffraction/scattering particle size
distribution measurement apparatus, a phosphorus atom content of
23.5 mass %, a solubility in water at 30.degree. C. of less than
0.2 mass %, and a melting point and a decomposition temperature
exceeding 250.degree. C.
[0152] The second polyurethane emulsion contained 10 mass % of the
second polyurethane and 28 mass % of the dialkyl phosphinic acid
metal salt. The second polyurethane was a forcedly emulsified
amorphous polycarbonate urethane having a 100% modulus of 1.0 MPa
and including 4,4'-dicyclohexylmethane diisocyanate as the
diisocyanate component.
[0153] Then, the napped artificial leather gray fabric that had
been subjected to the flame retardant treatment was shrunk in the
vertical direction (length direction) by 5.0% by being subjected to
a shrinkage processing treatment at a drum temperature 120.degree.
C. and a transport speed of 10 m/min, and thereafter the surface
thereof was subjected to a sealing treatment, thus obtaining a
napped artificial leather including a suede-like napped surface.
The napped artificial leather had a thickness of 0.4 mm, a basis
weight of 225 g/m.sup.2, and an apparent density of 0.56
g/cm.sup.3.
[0154] The napped artificial leather contained 10 mass % of the
first polyurethane, 5 mass % of the second polyurethane, and 14.4
mass % of the dialkyl phosphinic acid metal salt particles. As a
result, the napped artificial leather contained 3.4 mass % of the
dialkyl phosphinic acid metal salt as a content ratio in terms of
phosphorus atoms. The mass % in terms of phosphorus atoms to the
total amount of the dialkyl phosphinic acid metal salt particles,
the first polyurethane, and the second polyurethane was 11.5 mass
%. The mass % in terms of phosphorus atoms to the total amount of
the second polyurethane and the dialkyl phosphinic acid metal salt
particles was 17.4 mass %.
[0155] Then, the obtained napped artificial leather was evaluated
according to the following evaluation methods.
[0156] The results of the above evaluation are shown in Table 3
below.
TABLE-US-00003 TABLE 3 Example No. 12 13 14 15 16 17 Artificial
Ultrafine Fineness 0.1 0.1 0.1 0.1 0.4 0.2 leather fibers (dtex)
Resin PET PET PET PET PET PET First elastic Content (C) 10 9 19 11
10 10 polymer (mass %) Second elastic Content (D) 5 11 5 3 5 4
polymer (mass %) Phosphorous- Content (E) 14.4 13.6 12.6 8.9 14.5
14.4 based flame (mass %) retardant Compound Dialkyl Dialkyl
Dialkyl Dialkyl Monoalkyl Aromatic particles phosphinic phosphinic
phosphinic phosphinic phosphinic phosphinic acid acid acid acid
acid acid metal salt metal metal metal metal ester salt salt salt
salt Dispersed 4 4 4 4 2 5 particle size (D.sub.50: .mu.m) Water
<0.2% <0.2% <0.2% <0.2% <0.1% <0.1% solubility
(%: 30.degree. C.) Melting point, >250.degree. C.
>250.degree. C. >250.degree. C. >250.degree. C.
>250.degree. C. >250.degree. C. or decomp- osition
temperature in the absence of melting point (.degree. C.)
Phosphorus 23.5 23.5 23.5 23.5 28 15 atom content (mass %) (F)
Content ratio of phosphorous- 17.4 13.0 16.8 17.6 20.8 11.7 based
flame retardant particles in total amount of phosphorous- based
flame retardant particles and second elastic polymer ((E) * (F)/(D
+ E)) (mass %) Content ratio of phosphorous- 11.5 9.5 8.1 9.1 13.8
7.6 based flame retardant particles in total amount of phosphorous-
based flame retardant particles, first elastic polymer, and second
elastic polymer ((E) * (F)/ (C + D + E)) (mass %) Content ratio in
terms of 3.4 3.2 3.0 2.1 4.1 2.2 phosphorus atoms (E) *
(F)/100(mass %) Phosphorous-based flame 4 4 4 4 2 5 retardant
average particle size (SEM: .mu.m) Thickness from back surface in
150 150 120 180 180 180 which phosphorous-based flame retardant
particles and second elastic polymer are present (L: .mu.m)
Thickness of napped artificial 0.4 0.4 0.4 0.4 0.4 0.4 leather (T:
mm) Ratio of thickness L to 38 38 30 45 45 45 thickness T (%) Basis
weight g/m.sup.2 225 235 256 205 220 210 Apparent g/cm.sup.3 0.56
0.56 0.59 0.54 0.56 0.56 density Surface quality appearance A A A A
A A Burn test Burn distance 110 125 115 115 105 120 (Self-extin-
(mm) guishing Self-exting- 0 1.5 1 0 0 0 properties) uishing time
(sec) Drop self- 0 0 0 0 0 0 extinguishing time (sec) Composite
Adhesive Starch- Vinyl Chlorine- Nitrile Starch-vinyl Starch-
material vinyl acetate- metal- phenol- acetate- vinyl acetate-
based salt based based acetate- based resin based resin resin based
resin resin resin Interior backing material Calcium Calcium Gypsum
Calcium Gypsum Fiber (back board) silicate silicate silicate cement
Smoke test Smoke 5 6 8 6.5 14 6 density (SPR) Combustion Total heat
6.5 7 9.5 8 8 7 heat release test release (THR: MJ/ m.sup.2 20 min)
Peak heat 150 160 230 180 200 155 release rate (PHRR: kW/m.sup.2)
Time for 0 0 7 2 5 0 which PHR exceeded 200 kW/m.sup.2 (sec)
Maximum 35 40 80 50 60 40 average rate of heat emission (MARHE)
(kW/m.sup.2) Example No. 18 19 20 21 22 Artificial Ultrafine
Fineness 0.2 0.001 0.001 0.1 0.1 leather fibers (dtex) Resin PET Ny
Ny PET PET First Content (C) 9 31 25 10.2 10 elastic (mass %)
polymer Second Content (D) 4 5 9 3.9 5 elastic (mass %) polymer
Phosphorous- Content (E) 17.2 13.8 25.2 10.8 14.4 based (mass %)
flame Compound Phosphoric Dialkyl Dialkyl Dialkyl Dialkyl retardant
acid ester phos- phos- phos- phosphonic particles amide phinic acid
phonic acid phonic acid acid metal metal salt metal salt metal salt
salt Dispersed 8 4 4 4 4 particle size (D.sub.50: .mu.m) Water
solubility <0.1% <0.1% <0.1% <0.1% <0.2% (%:
30.degree. C.) Melting point, >250.degree. C. >250.degree. C.
>250.degree. C. >250.degree. C. >250.degree. C. or decomp-
osition temp- erature in the absence of melting point (.degree. C.)
Phosphorus 17 23.5 23.5 23.5 23.5 atom content (mass %) (F) Content
ratio of 13.8 17.3 17.3 17.3 17.4 phosphorous-based flame retardant
particles in total amount of phosphorous-based flame retardant
particles and second elastic polymer ((E) * (F)/(D + E)) (mass %)
Content ratio of 9.7 6.5 10.0 10.2 11.5 phosphorous-based flame
retardant particles in total amount of phosphorous-based flame
retardant particles, first elastic polymer, and second elastic
polymer ((E) * (F)/ (C + D + E)) (mass %) Content ratio in terms
2.9 3.2 5.9 2.5 3.4 of phosphorus atoms (E) * (F)/100 (mass %)
Phosphorous-based 8 4 4 4 4 flame retardant average particle size
(SEM: .mu.m) Thickness from back 120 180 180 150 190 surface in
which phosphorous-based flame retardant particles and second
elastic polymer are present (L: .mu.m) Thickness of napped 0.4 0.5
0.3 0.55 1.0 artificial leather (T: mm) Ratio of thickness L to 30
36 60 27 19 thickness T (%) Basis weight g/m.sup.2 230 225 128 300
300 Apparent g/cm.sup.3 0.57 0.45 0.43 0.54 0.30 density Surface
quality appearance A A A A A Burn test (Self- Burn distance 120 120
85 95 120 extinguishing (mm) properties) Self- 1 0 0 2 4
extinguishing time (sec) Drop self- 0 0 0 0 0 extinguishing time
(sec) Composite Adhesive Vinyl Vinyl Vinyl Chlorine- Starch-
material acetate- acetate- acetate- metal- vinyl based based based
salt acetate- resin resin resin based based resin resin Interior
backing material Calcium Calcium Gypsum Calcium Calcium (back
board) silicate silicate silicate silicate Smoke test Smoke density
8 4 3 12 9 (SPR) Combustion Total heat 8 7 7 10 8 heat release
release test (THR: MJ/m.sup.2 20 min) Peak heat 210 220 200 240 200
release rate (PHRR: kW/m.sup.2) Time for 6 5 4 7 6 which PHR
exceeded 200 kW/m.sup.2 (sec) Maximum 80 60 50 85 85 average rate
of heat emission (MARHE) (kW/m.sup.2)
Example 13
[0157] A napped artificial leather was obtained in the same manner
as in Example 12 except that a second polyurethane emulsion
containing 22 mass % of the second polyurethane and 28 mass % of
the dialkyl phosphinic acid metal salt was used in place of the
second polyurethane emulsion containing 10 mass % of the second
polyurethane and 28 mass % of the dialkyl phosphinic acid metal
salt, and the obtained napped artificial leather was evaluated. The
results are shown in Table 3.
Example 14
[0158] A napped artificial leather was obtained in the same manner
as in Example 12 except that a napped artificial leather having a
first polyurethane content of 19 mass % was produced in place of
the napped artificial leather having a first polyurethane content
of 10 mass %, and the obtained napped artificial leather was
evaluated. The results are shown in Table 3.
Example 15
[0159] A napped artificial leather was obtained in the same manner
as in Example 12 except that the second polyurethane emulsion in
which the dialkyl phosphinic acid metal salt particles serving as
the phosphorous-based flame retardant were dispersed was applied at
60 g/m.sup.2, instead of being applied at 110 g/m.sup.2, and the
obtained napped artificial leather was evaluated. The results are
shown in Table 3.
Example 16
[0160] In Example 12, a non-woven fabric in which fiber bundles
each including six ultrafine fibers of 0.4 dtex were
three-dimensionally entangled was formed in place of the non-woven
fabric in which fiber bundles each including 25 ultrafine fibers of
0.1 dtex were three-dimensionally entangled. In addition, as the
first polyurethane, a self-emulsified polyurethane having a mass
ratio between the amorphous polycarbonate polyol and the polyether
polyol of 60/40, and having a 100% modulus of 3.0 MPa was used in
place of the self-emulsified amorphous polycarbonate urethane
having a 100% modulus of 3.0 MPa and including 4,4'-diphenylmethane
diisocyanate as the diisocyanate component. Furthermore, the
monoalkyl phosphinic acid metal salt shown in Table 3 was used in
place of the dialkyl phosphinic acid metal salt as the
phosphorus-based flame retardant particles. Otherwise, a napped
artificial leather was obtained in the same manner, and the
obtained napped artificial leather was evaluated. The results are
shown in Table 3.
Example 17
[0161] A napped artificial leather was obtained in the same manner
as in Example 12 except that the aromatic phosphonic acid ester
shown in Table 3 was used in place of the dialkyl phosphinic acid
metal salt as the phosphorous-based flame retardant particles, and
the obtained napped artificial leather was evaluated. The results
are shown in Table 3.
Example 18
[0162] A napped artificial leather was obtained in the same manner
as in Example 12 except that the phosphoric acid ester amide shown
in Table 3 was used in place of the dialkyl phosphinic acid metal
salt as the phosphorous-based flame retardant particles, and the
obtained napped artificial leather was evaluated. The results are
shown in Table 3.
Example 19
[0163] In Example 12, polyethylene and 6-nylon were mixed at a mass
ratio of 50/50, and molten, and the molten resins were supplied to
a blend spinning spinneret, and discharged from the nozzle holes.
The average number of islands of the resulting fibers was
approximately 600, and the fibers were stretched, to give fibers of
5.5 dtex. The fibers were crimped, and thereafter cut into 51 mm
and carded, thus obtaining a staple web having a basis weight of
100 g/m.sup.2. This web was laid in six layers using a cross lapper
apparatus, to form a superposed web, and an oil solution was
sprayed thereto, and thereafter the web was needle punched at a
density of 1500 punch/cm.sup.2, followed by hot pressing, to obtain
a fiber-entangled body having an apparent density of 0.40
g/cm.sup.3 and a thickness of 1.2 mm. Then, the fiber-entangled
body was impregnated with a polyurethane dissolved in
N,N-dimethylformamide at the mass ratio shown in Table 3 as the
first polyurethane, the polyurethane including a diisocyanate
component composed of 4,4'-diphenylmethane diisocyanate, and a
polymer polyol composed of a polycarbonate polyol and a polyester
polyol at a mass ratio of 75/25, and having a 100% modulus of 5.0
MPa. Thereafter, the fiber-entangled body was immersed in a liquid
mixture of N,N-dimethylformamide and water for coagulation, and
then the polyethylene was extracted with toluene, and dried. After
that, a napped artificial leather was obtained in the same manner
as in Example 12 except that dye was changed from the disperse dye
to a metal complexed dye, and the obtained napped artificial
leather was evaluated. The results are shown in Table 3.
Example 20
[0164] A napped artificial leather having a thickness of 0.3 mm, a
basis weight of 128 g/m.sup.2 and an apparent density of 0.43
g/cm.sup.3 was obtained in the same manner as in Example 19 except
that the number of layers in which the staple web was laid was
changed from six to four, and the obtained napped artificial
leather was evaluated. The results are shown in Table 3.
Example 21
[0165] A napped artificial leather having a thickness of 0.55 mm, a
basis weight of 300 g/m.sup.2, and an apparent density of 0.54
g/cm.sup.3 was obtained in the same manner as in Example 12 except
that the web was laid in 10 layers using a cross lapper apparatus
so as to have a total basis weight of 330 g/m.sup.2, and the
obtained napped artificial leather was evaluated. The results are
shown in Table 3.
Example 22
[0166] A napped artificial leather having a thickness of 1.0 mm, a
basis weight of 300 g/m2, and an apparent density of 0.30
g/cm.sup.3 was obtained in the same manner as in Example 12 except
that the web was laid in 32 layers, instead of 8 layers, using a
cross lapper apparatus, that the web was subjected to the
impregnation so as to have a first polyurethane content of 12 mass
%, and that the napped artificial leather gray fabric was not
subjected to the shrinkage treatment , and the obtained napped
artificial leather was evaluated. The results are shown in Table
3.
Comparative Example 6
[0167] A napped artificial leather was obtained in the same manner
as in Example 12 except that a second polyurethane emulsion
containing 10 mass % of the second polyurethane and 6.8 mass % of
the dialkyl phosphinic acid metal salt was used in place of the
second polyurethane emulsion containing 10 mass % of the second
polyurethane and 28 mass % of the dialkyl phosphinic acid metal
salt, and the obtained napped artificial leather was evaluated.
Note that the viscosity of the aqueous dispersion including the
phosphorous-based flame retardant particles and the second elastic
polymer was 100 mPasec. The results are shown in Table 4.
TABLE-US-00004 TABLE 4 Comparative Example No. Com. Com. Com. Com.
Com. Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Artificial Ultrafine Fineness
0.1 0.1 0.1 0.1 0.6 leather fibers (dtex) Resin PET PET PET PET PET
First Content (C) 11 10 10 10 10 elastic (mass %) polymer Second
Content (D) 6 0 5 5 5 elastic (mass %) polymer Phosphorous- Content
(E) 3.9 15.2 14.4 14.4 8.2 based (mass %) flame Compound Dialkyl
Ammonium Ammonium Aromatic Dialkyl retardant phosphinic poly- poly-
phosphoric phosphinic particles acid metal salt phosphate phosphate
acid ester acid metal salt Dispersed 4 20 20 0.5 4 particle size
(D.sub.50: .mu.m) Water <0.2% 0.5 0.5 <0.2% <0.2%
solubility (%: 30.degree. C.) Melting >250.degree. C.
>250.degree. C. >250.degree. C. 115.degree. C.
>250.degree. C. point, or decomposition temperature in the
absence of melting point (.degree. C.) Phosphorus 23.5 31 31 10
23.5 atom content (mass %) (F) Content ratio of phosphorous- 9.3
31.0 23.0 7.4 14.6 based flame retardant particles in total amount
of phosphorous-based flame retardant particles and second elastic
polymer ((E) * (F)/(D + E)) (mass %) Content ratio of phosphorous-
4.4 18.7 15.2 4.9 8.3 based flame retardant particles in total
amount of phosphorous-based flame retardant particles, first
elastic polymer, and second elastic polymer ((E) * (F)/ (C + D +
E)) (mass %) Content ratio in terms of 0.9 4.7 4.5 1.4 1.9
phosphorus atoms (E) * (F)/100(mass %) Phosphorous-based flame 4 20
20 Non- 4 retardant average particle particulate size (SEM: .mu.m)
Thickness from back surface 300 50 50 200 200 in which
phosphorous-based flame retardant particles and second elastic
polymer are present (L: .mu.m) Thickness of napped 0.4 0.4 0.4 0.4
0.75 artificial leather (T: mm) Ratio of thickness L 75 13 13 50 27
to thickness T (%) Basis weight g/m.sup.2 200 210 225 225 390
Apparent g/cm.sup.3 0.5 0.53 0.56 0.56 0.5 density Surface quality
appearance B B, D D C A Burn test Burn distance 300 140 165 300 260
(Self- (mm) extinguishing Self- 30 7 9.5 38 24 properties)
extinguishing time (sec) Drop self- 8 0 2.5 15 8 extinguishing time
(sec) Composite Adhesive Starch-vinyl Starch-vinyl Starch-vinyl
Starch-vinyl Starch-vinyl material acetate-based acetate-based
acetate-based acetate-based acetate-based resin resin resin resin
resin Interior backing Calcium Gypsum Gypsum Calcium Calcium
material (back board) silicate silicate silicate Smoke test Smoke
density 18 8 15 16 16 (SPR) Combustion Total heat 20 9 16 24 18
heat release release (THR: test MJ/m.sup.2 20 min) Peak heat 340
200 270 360 300 release rate (PHRR: kW/m.sup.2) Time for 16 8 14 18
18 which PHR exceeded 200 kW/m.sup.2 (sec) Maximum 160 60 120 180
110 average rate of heat emission (MARHE) (kW/m.sup.2)
Comparative Example 7
[0168] A napped artificial leather was obtained in the same manner
as in Example 12 except that an aqueous dispersion containing 28
mass % of ammonium polyphosphate having a dispersed particle size
of 20 .mu.m was used in place of the second polyurethane emulsion
containing 10 mass % of the second polyurethane and 28 mass % of
the dialkyl phosphinic acid metal salt, and the obtained napped
artificial leather was evaluated. Note that the viscosity of the
aqueous dispersion including the phosphorous-based flame retardant
particles and the second elastic polymer was 100 mPasec. The
results are shown in Table 4.
Comparative Example 8
[0169] A napped artificial leather was obtained in the same manner
as in Example 12 except that the first polyurethane that was the
self-emulsified amorphous polycarbonate urethane having a 100%
modulus of 3.0 MPa and including 4,4'-dicyclohexylmethane
diisocyanate as the diisocyanate component was changed to a first
polyurethane that was a self-emulsified amorphous polycarbonate
urethane having a 100% modulus of 2.0 MPa and including
1,6-hexamethylene diisocyanate as the diisocyanate component, and
also that the ammonium polyphosphate shown in Table 1 was used in
place of the dialkyl phosphinic acid metal salt as the
phosphorous-based flame retardant particles, and the obtained
napped artificial leather was evaluated. The results are shown in
Table 4.
Comparative Example 9
[0170] A napped artificial leather was obtained in the same manner
as in Example 12 except that the aromatic phosphoric acid ester
shown in Table 4 was used in place of the dialkyl phosphinic acid
metal salt as the phosphorous-based flame retardant particles, and
the obtained napped artificial leather was evaluated. The results
are shown in Table 4. Note that the phosphorous-based flame
retardant was treated in the form of an aqueous dispersion during
the flame retardant treatment. However, as a result of observation
of the napped artificial leather, the phosphorous-based flame
retardant had formed a resin film, and was not in the particulate
form.
Comparative Example 10
[0171] A napped artificial leather was obtained in the same manner
as in Example 12 except that the number of the island components
formed with the spinneret was changed from 25 to 4, and that the
number of layers in which the web of the napped artificial leather
was laid was changed from 8 to 16, and the obtained napped
artificial leather was evaluated. The results are shown in Table
4.
[0172] Referring to Tables 3 and 4, all of the artificial leather
base materials obtained in Examples 12 to 22 had a favorable
surface quality appearance and a flexible texture, and furthermore,
exhibited favorable self-extinguishing properties, and reduced
smoke generation and combustion heat release, thus realizing napped
artificial leathers having a high level of flame retardancy. On the
other hand, in the case of the napped artificial leather obtained
in Comparative Example 6, which included a smaller amount of the
phosphorous-based flame retardant particles, and in which the flame
retardant particles were present even in the interior, the
phosphorous-based flame retardant was exposed on the surface,
resulting in deterioration in the surface quality appearance. In
the case of the napped artificial leather obtained in Comparative
Example 7, for which ammonium polyphosphate was used as the
phosphorous-based flame retardant particles, bleeding had occurred
over time, resulting in a poor appearance. In the case of the
napped artificial leather obtained in Comparative Example 8,
bleeding had occurred over time, resulting in a poor appearance.
Comparative Example 9, in which the phosphorous-based flame
retardant particles were changed to an aromatic phosphoric acid
ester, had a hard texture. Comparative Example 10, in which the
napped artificial leather had a high fineness and also a high basis
weight, was inferior in flame retardancy.
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