U.S. patent application number 10/518406 was filed with the patent office on 2006-03-02 for highly durable polybenzazole composition, fiber and film.
Invention is credited to Yukihiro Abe, Hironori Eguchi, Takaharu Ichiryu, Kohei Kiriyama, Tadao Kuroki, Go Matsuoka, Hiroki Murase, Muneatsu Nakamura, Yokihiro Nomura, Yukinari Okuyama.
Application Number | 20060046049 10/518406 |
Document ID | / |
Family ID | 35943597 |
Filed Date | 2006-03-02 |
United States Patent
Application |
20060046049 |
Kind Code |
A1 |
Abe; Yukihiro ; et
al. |
March 2, 2006 |
Highly durable polybenzazole composition, fiber and film
Abstract
There is provided a polybenzazole fiber or film containing a
basic organic compound in the form of a monomer or a condensate,
selected from the group consisting of guanidines, triazoles,
quinazolines, piperidines, anilines, pyridines, cyanuric acids, and
p-phenylenediamine, m-phenylenediamine and a mixture thereof. This
fiber has characteristics in that the X-ray meridian diffraction
half-width factor is 0.3.degree./GPa or less, that the elasticity
decrement (Er) attributed to change of molecular orientation is 30
GPa or less, and that the breaking strength is 1 GPa or more. This
fiber can be used in staple fiber, a spun yarn, a woven or knit
fabric, a felt material, a composite material, a cord, a rod, a
fibrous sheet, a knife proof vest or a bullet proof vest.
Inventors: |
Abe; Yukihiro; (Otsu,
JP) ; Matsuoka; Go; (Otsu, JP) ; Kiriyama;
Kohei; (Otsu, JP) ; Murase; Hiroki; (Otsu,
JP) ; Nakamura; Muneatsu; (Otsu, JP) ; Nomura;
Yokihiro; (Otsu, JP) ; Eguchi; Hironori;
(Osaka, JP) ; Okuyama; Yukinari; (Osaka, JP)
; Kuroki; Tadao; (Osaka, JP) ; Ichiryu;
Takaharu; (Osaka, JP) |
Correspondence
Address: |
KENYON & KENYON
1500 K STREET NW
SUITE 700
WASHINGTON
DC
20005
US
|
Family ID: |
35943597 |
Appl. No.: |
10/518406 |
Filed: |
June 26, 2003 |
PCT Filed: |
June 26, 2003 |
PCT NO: |
PCT/JP03/08067 |
371 Date: |
August 12, 2005 |
Current U.S.
Class: |
428/364 |
Current CPC
Class: |
C08G 73/18 20130101;
Y10T 428/2913 20150115; C08G 73/22 20130101; D01F 1/10 20130101;
D01F 6/74 20130101 |
Class at
Publication: |
428/364 |
International
Class: |
D02G 3/00 20060101
D02G003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 26, 2002 |
JP |
2002-186419 |
Aug 20, 2002 |
JP |
2002-239699 |
Sep 9, 2002 |
JP |
2002-263185 |
Sep 9, 2002 |
JP |
2002-263186 |
Sep 9, 2002 |
JP |
2002-263184 |
Oct 22, 2002 |
JP |
2002-307543 |
Claims
1. A polybenzazole composition containing a basic substance.
2. A polybenzazole composition according to claim 1, wherein the
basic substance is an organic compound.
3. A polybenzazole composition according to claim 1, wherein the
basic substance is an organic compound soluble in water or a
hydrophilic solvent.
4. A polybenzazole composition according to claim 1, wherein the
basic substance is selected from the group consisting of
guanidines, triazoles, quinazolines, piperidines, anilines,
pyridines and cyanuric acids.
5. A polybenzazole fiber comprising a polybenzazole composition
according to claim 1.
6. A polybenzazole film comprising a polybenzazole composition
according to claim 1.
7. A polybenzazole fiber according to claim 5, which contains a
basic organic compound in the form of a monomer or a
condensate.
8. A polybenzazole fiber according to claim 5, which contains a
basic organic compound selected from the group consisting of
p-phenylenediamine, m-phenylenediamine and a mixture thereof in the
form of a monomer or a condensate.
9. A polybenzazole fiber according to claim 5, wherein the X-ray
meridian diffraction half-width factor is 0.3.degree./GPa or
less.
10. A polybenzazole fiber according to claim 5, wherein the
elasticity decrement Er attributed to change of molecular
orientation is 30 GPa or less.
11. A polybenzazole fiber according to claim 5, wherein the
breaking strength of the fiber is 1 GPa or more.
12. A polybenzazole fiber according to claim 5, which is a staple
fiber.
13. A polybenzazole spun yarn comprising a polybenzazole fiber
according to claim 5.
14. A polybenzazole woven or knitted fabric comprising a
polybenzazole fiber according to claim 5.
15. A polybenzazole felt material comprising a polybenzazole fiber
according to claim 5.
16. A polybenzazole composite material comprising a polybenzazole
fiber according to claim 5.
17. A polybenzazole cord comprising a polybenzazole fiber according
to claim 5.
18. A polybenzazole rod comprising a polybenzazole fiber according
to claim 5.
19. A polybenzazole fibrous sheet for reinforcing cement and
concrete, said sheet comprising a polybenzazole fiber according to
claim 5.
20. A polybenzazole fibrous sheet for reinforcing cement and
concrete, wherein the breaking strength of said sheet is 50 kg/cm
or more.
21. A high strength fiber comprising a polybenzazole fiber
according to claim 5.
22. A knife-proof vest comprising a polybenzazole fiber according
to claim 5.
23. A bullet-proof vest comprising a polybenzazole fiber according
to claim 5.
Description
FILED OF THE INVENTION
[0001] The present invention relates to a highly durable
polybenzazole composition containing a stabilizing agent for
imparting excellent storage stability to polybenzazole, and fibers
and films made of the polybenzazole composition, and the use
thereof.
BACKGROUND OF THE INVENTION
[0002] As high heat resistant and high strength fibers, there are
known fibers made of polybenzoxazole (PBO), polybenzimidazole (PBI)
or polybenzothiazole (PBT) (hereinafter referred to as
polybenzazole).
[0003] Generally, polybenzazole fibers are manufactured by spinning
a dope of a liquid crystalline polymer in a mineral acid as a
solvent. The polymer dope is extruded through a spinneret, and the
resultant filaments are washed with water so as to extract the
mineral acid into the bath containing water. In this washing step,
the filaments are thoroughly washed with water, and allowed to pass
through a bath containing an aqueous solution of an inorganic basic
compound such as sodium hydroxide or the like to thereby neutralize
the remaining mineral acid which has not been extracted from the
filaments. After that, the filaments are again washed. It is very
important to impregnate the filaments with the basic compound until
the internal conditions of the filaments are neutralized. When the
conditions of water washing and the amount of the inorganic basic
compound to be added change for some reasons, the internal
conditions of the filaments become acidic or basic.
[0004] If the mineral acid remains in the polybenzazole filaments
which are insufficiently neutralized, such polybenzazole filaments
tend to degrade in tensile strength, when exposed to an atmosphere
of high temperature and high humidity over a long period of
time.
[0005] Under these circumstances, there are demands for
polybenzazole fibers and films which show less decrease in strength
when exposed to atmospheres of high temperatures and high humidity
over long periods of time, even though the polybenzazole fibers and
films contain mineral acids which are insufficiently neutralized
for some reason to remain in the fibers and films. An object of the
present invention is therefore to provide polybenzazole which shows
less decrease in strength.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows a schematic diagram of an apparatus for
measuring the X-ray diffraction of a filament under a tension.
[0007] FIG. 2 shows a graph for evaluating the half width factors
(Hws).
[0008] FIG. 3 shows a graph for indicating changes of molecular
orientation (<sin.sup.2.phi.>)
[0009] FIG. 4 shows a schematic diagram of a high temperature
abrasion tester used for the measurement of abrasion
resistance.
[0010] FIG. 5 shows a schematic diagram of a cheese dyeing
apparatus.
[0011] In the drawings, numeral 1 refers to an abrading material;
2, to a heater; 3, to a weight; 4, to a motor; 5, to a sample
holder; 6, to a sample; 7, to a treating bath; 8, to a treatment
liquid; 9, to a non-dried waywound yarn; 10, to a water permeable
porous bobbin; 11, to the cap of the bobbin; and 12, to a treatment
liquid-circulating pump.
DISCLOSURE OF THE INVENTION
[0012] The present inventors have intensively researched in order
to solve the foregoing problems, and finally accomplished the
present invention.
[0013] That is, the present invention provides the following.
[0014] 1. A polybenzazole composition containing a basic
substance.
[0015] 2. A polybenzazole composition according to the above
paragraph 1, in which the basic substance is an organic
compound.
[0016] 3. A polybenzazole composition according to the above
paragraph 1, in which the basic substance is an organic compound
soluble in water or a hydrophilic solvent.
[0017] 4. A polybenzazole composition according to the above
paragraph 1, in which the basic substance is selected from the
group consisting of guanidines, triazoles, quinazolines,
piperidines, anilines, pyridines and cyanuric acids.
[0018] 5. A polybenzazole fiber comprising a polybenzazole
composition according to the above paragraph 1.
[0019] 6. A polybenzazole film comprising a polybenzazole
composition according to the above paragraph 1.
[0020] 7. A polybenzazole fiber according to the above paragraph 5,
which contains a basic organic compound in the form of a monomer or
a condensate.
[0021] 8. A polybenzazole fiber according to the above paragraph 5,
which contains a basic organic compound selected from the group
consisting of p-phenylenediamine, m-phenylenediamine and a mixture
thereof, in the form of a monomer or a condensate.
[0022] 9. A polybenzazole fiber according to the above paragraph 5,
in which the X-ray meridian diffraction half-width factor is
0.3.degree./GPa or less.
[0023] 10. A polybenzazole fiber according to the above paragraph
5, in which the elasticity decrement Er attributed to change of
molecular orientation is 30 GPa or less.
[0024] 11. A polybenzazole fiber according to the above paragraph
5, in which the breaking strength of the fiber is 1 GPa or
more.
[0025] 12. A polybenzazole fiber according to the above paragraph
5, which is a staple fiber.
[0026] 13. A polybenzazole spun yarn comprising a polybenzazole
fiber according to the above paragraph 5.
[0027] 14. A polybenzazole woven or knitted fabric comprising a
polybenzazole fiber according to the above paragraph 5.
[0028] 15. A polybenzazole felt material comprising a polybenzazole
fiber according to the above paragraph 5.
[0029] 16. A polybenzazole composite material comprising a
polybenzazole fiber according to the above paragraph 5.
[0030] 17. A polybenzazole cord comprising a polybenzazole fiber
according to the above paragraph 5.
[0031] 18. A polybenzazole rod comprising a polybenzazole fiber
according to the above paragraph 5.
[0032] 19. A polybenzazole fibrous sheet for reinforcing cement and
concrete, said sheet comprising a polybenzazole fiber according to
the above paragraph 5.
[0033] 20. A polybenzazole fibrous sheet for reinforcing cement and
concrete, according to the above paragraph 19, in which the
breaking strength of said sheet is 50 kg/cm or more.
[0034] 21. A high strength fiber comprising a polybenzazole fiber
according to the above paragraph 5.
[0035] 22. A knife proof vest comprising a polybenzazole fiber
according to the above paragraph 5.
[0036] 23. A bullet proof vest comprising a polybenzazole fiber
according to the above paragraph 5.
[0037] Hereinafter, the present invention will be described in more
detail.
[0038] Examples of the guanidiens to be used in the present
invention include aminoguanidine bicarbonate,
1,3-bis(2-benzothiazolyl)guanidine, 1,3-diphenylguanidine,
1,3-di(o-toluyl)guanidine, 1,2,3-triphenylguanidine and the like.
Examples of the triazoles include
2-(2-hydroxy-5-methylphenyl)benzotriazole, 3-amino-1,2,4-triazole,
2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimide-methyl)-5-methylphenyl]benz-
otriazole, 2-(3,5-di-tert.-butyl-2-hydroxyphenyl)benzotriazole and
the like. Examples of the quinazolines include
quinazoline-2,4-dione and the like. Examples of the piperidines
include piperadine and the like. Examples of the anilines include
anililne, o-hydroxyanyline, o-phenoxyaniline, p-hydroxyaniline and
the like. Examples of the pyridines include pyridine and the like.
Examples of the cyanuric acid include isocyanuric acid and the
like.
[0039] Each of these basic organic compounds may be used alone or
in combination. The amount of the basic organic compound to be
added is 0.01 to 20%, preferably 0.1 to 10%.
[0040] The basic organic compounds to be used in the present
invention are not limited to the above compounds.
[0041] The polybenzazole referred to in the present invention is at
least one polymer selected from the group consisting of
polybenzoxazole (PBO), polybenzothiazole (PBT) and
polybenzimidazole (PBI). In the present invention, PBO is a polymer
containing an oxazole ring bonded to an aromatic group which is not
necessarily a benzene ring. Examples of PBO include a wide range of
polymers each of which comprises a unit of a plurality of oxazole
rings bonded to poly(phenylenebenzobisoxazole) and aromatic groups.
Similarly, PBT and PBI have analogous structures as above. Examples
of the polybenzazole further include mixtures, and copolymers or
block polymers of two or more polybenzazole polymers, such as
mixtures of PBO and PBT and/or PBI, and block or random copolymers
of PBO, PBT and PBI. Preferably, the polybenzazole is a lyotropic
liquid crystal polymer which forms a liquid crystal in a mineral
acid at a specified concentration, and polybenzoxazole is preferred
in the present invention.
[0042] Preferably, the structural unit contained in a PBZ polymer
is selected from lyotropic liquid crystal polymers. The monomer
unit contained in the polymer is selected from the monomer units
represented by the following formulas (a) to (i) ##STR1##
[0043] A solution of a polybenzazole polymer (hereinafter referred
to as a polymer dope) is readily prepared by polymerizing a
polybenzazole polymer in an acidic solvent. The solvent to be used
is preferably a mineral acid such as sulfuric acid, methanesulfonic
acid or polyphosphoric acid, and the most preferable is
polyphosphoric acid. The concentration of the polymer in the dope
is 1 to 30%, preferably 1 to 20%.
[0044] In the present invention, suitable polymers or copolymers
and dopes are prepared by any of known methods, described, for
example, in U.S. Pat. No. 4,533,693 by Wolfe et al. (Aug. 6, 1985),
U.S. Pat. No. 4,772,678 by Sybert et al. (Sep. 22, 1988), U.S. Pat.
No. 4,847,350 by Harris (Jul. 11, 1989) and U.S. Pat. No. 5,089,591
by Gregory et al. (Feb. 18, 1992). To sum up, a suitable polymer or
copolymer is reacted in a solution of a non-oxidizing and
dehydrating acid, by raising the temperature stepwise or at a given
rate within a range of about 60.degree. C. to about 230.degree.,
while stirring and shearing at high speeds under a non-oxidizing
atmosphere.
[0045] The dope thus prepared is extruded throuogh a spinneret, and
the extrusions are drawn long in an air to form filaments.
Preferred methods therefor are described in the above patent
literature and U.S. Pat. No. 5,034,250. The dope extrusions having
passed through the spinneret enter a space between the spinneret
and a washing bath. This space is generally called an air gap, but
is not always charged with an air. It is needed to fill this space
with a medium which does not act to remove the solvent and which is
non-reactive with the dope, such as an air, nitrogen, argon,
helium, carbon dioxide or the like.
[0046] The resultant filaments are washed to remove a part of the
solvent so as to avoid excessive elongation thereof. The filaments
are further washed and neutralized with a suitable inorganic basic
substance such as sodium hydroxide or the like, and then further
washed. Most of the solvent was removed by this step. The washing
herein referred to means that the fibers or filaments are allowed
to contact a liquid which is compatible with the mineral acid
dissolving the polybenzazole polymer and which is not a solvent for
the polybenzazole polymer, so as to remove the acid solvent from
the dope. As a suitable washing liquid, water or a mixture of water
and an acid solvent can be used. Preferably, the filaments are so
washed that the concentration of the residual mineral acid can be
8,000 ppm or lower, more preferably 5,000 ppm or lower. After that,
the filaments are dried, heat-treated and wound, as required.
[0047] To form a film, typically, a viscous polymer dope may be
extruded onto a rotary drum to form an uniaxial oriented film, as
described in U.S. Pat. No. 4,487,735. This film is tube-like
extruded and is blown on or pushed in a mandrel to thereby
biaxially orient the film. Then, the film is dipped in water to be
solidified. Thus, the solid film can be formed. The film may be
further washed to remove the solvent.
[0048] The method of preparing a polybenzazole composition of the
present invention, in other words, the method of containing the
above basic substance in polybenzazole is not particularly limited.
The basic substance may be contained in polybenzazole during the
polymerization of polybenzazole, during the washing of the dope,
before the drying of the filaments, or during the post-processing
of the filaments. Preferably, to add the basic substance during the
polymerization of polybenzazole, the basic substance is
simultaneously added with the starting materials; the basic
substance is added at an optional point of time during the reaction
while the temperature is being increased stepwise or at a constant
rate; or the basic substance is added after the completion of the
polymerization. Preferably, to add the basic substance during the
washing of the dope or before the drying of the filaments, the
basic substance is dissolved in water or a hydrophilic organic
solvent, and the dope, filaments or a film is dipped in the
resultant solution. Preferably, to add the basic substance during
the post-processing step at which the dope, the filaments or the
film has had a solid structure, the basic substance is dissolved in
a solvent, and a multifilament, staple fiber or fabric is dipped in
the resultant solution, and then is washed with a suitable solvent
to remove the solvent of the solution.
[0049] Such multifilament, staple or fabric can contain a
sufficient amount of the basic substance when dipped in the
solution for any number of seconds not shorter than 0.1 second,
preferably not shorter than 10 seconds. Further, two or more basic
substances may be simultaneously added thereto.
[0050] After washing with water, the multifilament, staple or
fabric is dried usually at a temperature of 300.degree. C. or lower
to thereby fix the basic substance therein. The tensile strength
retention of the multifilament, staple or fabric after undergoing
the heat treatment is 80% or more of the tensile strength of a
polybenzazole molded form which contains no basic substance, and
thus, it is known that the adverse influence of the heat treatment
on the polymer is a little.
[0051] The chemical conditions or actions of the basic substance in
the fibers have not been clearly known. However, the following are
simply supposed: moisture in an atmosphere of high temperature and
high humidity infiltrates the polybenzazole fibers or the film, so
that the residual mineral acid is dissociated by the moisture to
release protons, which are captured by the basic substance to
maintain the reaction system in a neutral state, to thereby prevent
a decrease in the strength of the fibers or the film. This idea,
however, does not restrict the present invention in any way.
[0052] The following method is recommended for the manufacturing of
the polybenzazole fibers.
[0053] The filaments resulting from the spinning are washed to
remove a part of the solvent so as to avoid excessive elongation
thereof. The filaments are further washed and neutralized with a
suitable inorganic base such as sodium hydroxide, calcium
hydroxide, potassium hydroxide or the like to thereby remove most
of the solvent. The washing herein referred to means that the
fibers or filaments are allowed to contact a liquid which is
compatible with the mineral acid dissolving the polybenzazole
polymer and which is not a solvent for the polybenzazole polymer,
so as to remove the acid solvent from the dope. As a suitable
washing liquid, water or a mixture of water and an acid solvent can
be used. Preferably, the filaments are so washed that the
concentration of the residual mineral acid can be 8,000 ppm or
lower, more preferably 5,000 ppm or lower. Desirably, the
stoichiometric ratio of the residual inorganic base to the residual
mineral acid in the filament is 0.9 to 1.6:1. After that, the
filaments are dried, heat-treated and wound, as required.
[0054] Firstly, the polybenzazole fibers of the present invention
are characterized in that the fibers contain a basic organic
compound in the form of a monomer or a condensate, so that the
fibers can have a tensile strength retention of 85% or more after
exposed to an atmosphere of a temperature of 80.degree. C. and a
relative humidity of 80% for 700 hours. The basic organic compound
herein referred to is not particularly limited, and it may be any
of organic compounds that show basic states, such as aromatic
amine.
[0055] It is preferable to contain the basic organic compound in
the fibers or filaments without allowing the fibers or filaments to
have a moisture regain of 20% or less. If the fibers or filaments
once have a moisture regain of 20% or less, the pores of the
surfaces of the fibers or filaments become narrower, so that the
surfaces of the fibers or filaments become dense. As a result, it
becomes hard for the basic organic compound to infiltrate the
fibers or filaments. As specific methods, there are given the guide
oiling method, the showering method, the dipping method or the like
is employed to contain the basic organic compound in the fibers or
filaments between the step of extruding the dope through the
spinneret and the step of drying the fibers or filaments.
Otherwise, the filaments are wound without drying, and dipped in a
solution of the basic organic compound to thereby contain the
compound in the fibers or filaments. In order for the fibers or
filaments to maintain a high strength retention after exposed to an
atmosphere of high temperature and high humidity over a long period
of time, preferably, the fibers or filaments are wound up without
drying, and dipped in a solution of the basic organic compound for
a relatively long time.
[0056] Secondly, the polybenzazole fibers of the present invention
are characterized in that the fibers contain a basic organic
compound selected from p-pheanylenediamine, m-phenylenediamine and
a mixture thereof, in the form of a monomer or a condensate. By
doing so, the fibers can have a tensile strength retention of 85%
or more, preferably 90% or more after exposed to an atmosphere of a
temperature of 80.degree. C. and a relative humidity of 80% for 700
hours. The use of other basic organic compounds is effective to
prevent the fibers from having a decreased strength attributed to
long term exposure to an atmosphere of high temperature and high
humidity. Among such other basic organic compounds,
phenylenediamine shows a marked effect. The amount of
phenylenediamine to be added is 10% or less, preferably 8% or less,
more preferably 2 to 6%. When it exceeds 10%, the fineness of the
filaments increases due to the increased amount of
phenylenediamine, which undesirably leads to a decrease in the
initial strength of the filaments.
[0057] Also, in this case, phenylenediamine is so contained in the
fibers that the fibers never have a moisture regain of 20% or less,
as well as the foregoing basic organic compounds. If the fibers
once have a moisture regain of 20% or less, the pores of the
surfaces of the fibers become narrower to dense the surfaces of the
fibers. As a result, it becomes hard for phenylenediamine to
infiltrate the fibers. As specific methods, there are given the
guide oiling method, the showering method, the dipping method or
the like is employed to contain phenylenediamine in the filaments
between the step of extruding the dope through the spinneret and
the step of drying the filaments. Otherwise, the fibers or
filaments are wound without drying, and dipped in an aqueous
solution of phenylenediamine to thereby contain the compound in the
filaments. In order for the filaments to maintain a high strength
retention after exposed to an atmosphere of high temperature and
high humidity for a long period of time, preferably, the filaments
are wound up without drying, and dipped in an aqueous solution of
phenylenediamine for a relatively long time. More preferably, the
filaments are treated by the cheese dyeing method for relatively
long time to thereby sufficiently infiltrate phenylenediamine into
the filaments.
[0058] The blending ratio of p-phenylenediamine to
m-phenylenediamine is 4:6 to 0:10: namely, it is preferable that
the amount of m-phenylenediamine is larger than that of
p-phenylenediamine.
[0059] The oxidative condensation of p-phenylenediamine rapidly
proceeds in water, and the condensation degree thereof quickly
increases in water, as compared with m-phenylenediamine. Therefore,
it is hard for the phenylenediamine condensate to enter the voids
of the filaments. Consequently, it becomes difficult for the
phenylenediamine condensate to sufficiently fill the voids of the
filaments and thereby stabilize them. As a result, it is sometimes
difficult for the filaments to have a tensile strength retention of
85% or more after exposed to an atmosphere of a temperature of
80.degree. C. and a relative humidity of 80% for 700 hours. It
becomes possible to stably fill the voids of the filaments with the
phenylenediamine condensate, by blending a larger amount of
m-phenylenediamine than that of p-phenylenediamine, taken into
consideration the slow oxidative condensation of
m-phenylenediamine. However, the use of m-phenylenediamine alone
makes it hard to accelerate the oxidative condensation, and
requires very long time to treat the filaments, which results in
poor productivity. To facilitate the oxidative condensation, the
filaments may be treated at a higher temperature, but the strength
of the fibers or filaments tends to lower during the treatment.
[0060] Therefore, more preferably, the blending ratio of
p-phenylenediamine to m-phenylenediamine is 3:7 to 1:9.
[0061] Thirdly, the polybenzazole fibers of the present invention
are characterized in that the X-ray meridian diffraction half-width
factor thereof is 0.3.degree./CPa or less, and that the elasticity
decrement Er attributed to change of molecular orientation is 30
GPa or less. The polybenzazole fibers unavoidably have voids
therein, since the solvent is removed from the dope as mentioned
above. Therefore, the fibers have defective structures attributed
to such voids. Accordingly, stresses concentrate on such defective
portions of the fibers until the fibers break. As a result, the
fibers break without sufficiently exhibiting their own
performance.
[0062] The breaking of the fibers or filaments is described in
detail. When the fibers have voids therein, the voids themselves
serve as deforming sites together with the deformation of the
fibers. These voids therefore facilitate the deformation of the
fibers in the direction of rotation of the crystals or in a
shearing direction. When this deformation exceeds a certain limit,
the fibers break. This time, the present inventors have intensively
researched a method of solving this problem. As a result, they have
found out that the basic organic compound, which is selected from
p-phenylenediamine, m-phenylenediamine and a mixture thereof in the
form of a monomer or a condensate and which is contained in the
fibers, fills the voids of the fibers or filaments to thereby
reinforce the same and to thereby decrease the defects of the
structures of the same. As a results of the inventors' intensive
researches, it is known that this effect can be expressed as an
X-ray meridian diffraction half-width factor or an elasticity
decrement Er attributed to change of molecular orientation.
[0063] While the chemical actions of the basic organic compound in
the fibers are not clearly known, the following can be simply
supposed. Since the micro voids in the polybenzazole fibers are
filled with the monomer or condensate of the basic organic
compound, external water vapor is hard to reach the PBZ molecules
even while the polybenzazole fibers are exposed to an atmosphere of
high temperature and high humidity over a long period of time. As a
result, the strength of the fibers is hard to decrease; or, the
mineral acid or the condensate thereof remaining in the
polybenzazole fibers is dissociated by moisture to release hydrogen
ions, which are then captured by the basic substance, so that the
reaction system is neutralized to thereby inhibit the decrease of
the strength of the fibers; or otherwise, the condensate of the
basic organic compound having a developed conjugate system captures
radicals which occur in the fibers for some reason, to thereby
stabilize the reaction system and inhibit the decrease in the
strength of the fibers. However, these ideas do not restrict the
present invention in any way.
[0064] The polybenzazole fibers thus obtained can have so high
durability as a tensile strength retention of 85% or more,
preferably 90% even after exposed to an atmosphere of a temperature
of as high as 80.degree. C. and a relative humidity of as high as
80% for 700 hours.
[0065] The breaking strength of the resultant fibers is so high as
1 GPa or more, preferably 2.75 GPa or more, still more preferably
4.10 GPa or more.
[0066] The staple fibers of the present invention are manufactured
as follows. If needed, the filaments are crimped with a push-on
crimper or the like. Then, the filaments are cut into staple fibers
with predetermined lengths, using a known means, for example, a
rotary cutter having a plurality of blades which are disposed
radially in a slit between a pair of rotors opposing to each other.
The length of the staple fibers is not particularly limited, and it
is preferably 100 to 0.05 mm, more preferably 70 to 0.5 mm.
[0067] The polybenzazole staple fibers can be widely used. The
staple fibers are variously processed to provide spun yarns, felt,
etc. Such spun yarns and felt are used for tension materials such
as cables and ropes; incision protective members such as gloves;
heat resistant and fire resistant materials such as fireman
uniforms, heat resistant felt, gaskets for plants, heat resistant
fabrics, a variety of sealing materials, heat resistant cushions
and filters; abrasion resistant materials such as continuous
vehicle transmission belt and clutch facing; reinforcements for
construction materials; rider suits; speaker cones; and the like.
The applications of the staple fibers are not limited to those.
[0068] Spun yarns comprising the polybenzazole fibers of the
present invention provide textile-materials for protective
materials, protective clothing and industrial materials.
[0069] Examples of the spun yarns of the present invention also
include composite spun yarns which comprise the polybenzazole
fibers with other fibers. As other fibers, there are given natural
fibers, organic fibers, metal fibers, inorganic fibers and mineral
fibers. There is no particular limit in selection of the blending
method, and the conventional mixed staple fiber at opening process,
and core-in sheath method can be employed.
[0070] Woven or knitted fabrics comprising the polybenzazole fibers
of the present invention provide textile materials for highly
durable protective materials, protective clothing and industrial
materials.
[0071] Examples of the woven or knitted fabrics of the present
invention also include composite woven or knitted fabrics combined
with other fibers such as natural fibers, organic fibers, metal
fibers, inorganic fibers, mineral fibers or the like. The method of
combination is not limited. The woven fabrics include union woven
fabrics, double weave fabrics, lip stop fabrics, etc. The knitted
fabrics include union knitted fabrics, double knit fabrics,
circular knitted fabrics, weft knitted fabrics, warp knitted
fabrics, raschel knitted fabrics, etc. Fiber or filament fluxes
composing the woven or knitted fabrics are not particularly
limited. Monofilaments, multifilaments, twist yarns, doubled twist
yarns, covering yarns, spun yarns, stretch breaking spun yarns,
core-in-sheath yarns and braids can be used.
[0072] Felt of the present invention is manufactured as follows.
The polybenzazole filaments obtained as above are crimped and cut
into polybenzazole staple fibers by any of known methods. The
resulting staple fibers are further processed into felt materials
by any of known methods.
[0073] As the felt-making method, a known non-woven fabric making
method can be employed. A web is made of the staple fibers, and the
web is formed into felt by the needle punching method, stitch
bonding method or water punching method, or by a method using a
binder. Otherwise, felt may be made of the polybenzazole filaments
by the spun-bonding method.
[0074] The felt materials of the present invention can be made of
blended staple fibers comprising the polybenzazole fibers and
different fibers. It is effective to increase the blending
percentage of the polybenzazole fibers, when the felt material is
demanded to have higher heat resistance. The weight percentage of
the polybenzazole fibers is preferably 50% or higher, more
preferably 80% or higher. When it is lower than 50%, the excellent
heat resistance and abrasion resistance of the polybenzazole fibers
can not be fully exhibited. There is no particular limit in
selection of the blending method, in so far as the felt comprises
homogeneously blended fibers, or comprises a lamination having two
or more felt layers which are made separately of different fibers
to be blended with the polybenzazole fibers, and such felts are
moldable.
[0075] The felt material thus obtained can sufficiently maintain
the strength even after exposed to an atmosphere of high
temperature and high humidity, since it comprises the polybenzazole
fibers which show less decrease in strength even after exposed to
an atmosphere of high temperature and high humidity over a long
period of time. As a result, the abrasion resistance of the felt
material under an atmosphere of high humidity is improved, which
makes it possible to improve the life of a heat resistant cushion
material comprising the felt material.
[0076] The composite materials comprising the polybenzazole fibers
of the present invention may be provided in any form such as
unidirectionally reinforced materials, pseudocubic laminations or
laminated fabrics. As the matrix resin, any of thermosetting resins
such as epoxy resins and phenol resins, super engineering plastics
such as PPS and PEEK, and general-purpose thermosetting resins such
as polyethylene, polypropylene and polyamide can be used.
[0077] The cords comprising the polybenzazole fibers of the present
invention are provided as single twist yarns or twist two-ply yarns
which are made with a ring twisting machine, to thereby improve the
fatigue resistance. The twist coefficient is sufficient to be 350
to 2,000.
[0078] The twist coefficient K=Tw.times.(Den/.rho.).sup.1/2
[0079] Tw: the number of twist [T/10 cm],
[0080] Den: total denier .rho.: fiber density [g/cm.sup.3]
[0081] To improve the adhesion to rubber, the surfaces of the
polybenzazole fibers or filaments may be subjected to corona
treatment or plasma treatment. Otherwise, a compound reactive with
the surfaces of the polybenzazole fibers or filaments or the
surface of the polybenzazole fibers or filaments treated with
corona may be applied to such polybenzazole fibers or filaments. To
further improve the adhesion to rubber, the polybenzazole fibers or
filaments may be subjected to a dipping treatment. As the treating
liquid, the following can be generally used:
[0082] (A) an aqueous dispersion of an epoxy resin,
[0083] (B) an aqueous dispersion of a blocked isocyanate,
[0084] (C) an aqueous dispersion of a rubber latex, and
[0085] (D) a liquid mixture of a resorcin formaldehyde resin and a
rubber latex (RFL).
[0086] Each of the treating liquids may be used alone or in
combination, for one-stage or multiple-stage treatment comprising
two or more steps. Other treating methods also may be employed.
[0087] The polybenzazole fiber rod for reinforcing cement and
concrete, of the present invention, is generally provided by
knitting the polybenzazole filaments as a braid, and setting hard
the braid with a thermosetting resin such as an epoxy resin. The
braid can have an optional diameter according to the size of the
filaments to be used. In view of the ease of handling, the diameter
of the braid is usually 1 to 20 mm. For example, when 16 strands
each having a fineness of 3,000 denier, made of the polybenzazole
fibers, is made into a braid (with a total fineness of 48,000
denier), the braid has a diameter of 2 mm. When a braid has a total
fineness of 752,000 denier, the braid has a diameter of 8 mm. The
diameter of the rod set hard with the resin varies depending on the
amount of the resin applied, and it is generally about 25% larger
than the diameter of the braid.
[0088] The polybenzazole fiber sheets for cement/concrete
reinforcement of the present invention are 100 to 1,500 g/m.sup.2
in weight, and the sheets comprise the polybenzazole fibers in at
least one direction thereof. When the weight of the sheet is below
100 g/m.sup.2, the sheet can not have a required strength, which
leads to the need of laminating an increased number of such sheets,
resulting in poor efficiency. When the weight exceeds 1,500
g/cm.sup.2, the impregnation of the sheet with a resin as adhesive
becomes poor, and the adhesion with cement and concrete becomes
poor.
[0089] The fiber sheet specifically means a woven fabric, knitted
fabric, non-woven fabric, net, net-like sheet in which the
intersections of filaments are fixed with adhesive, lamination of
films made of the fibers, or the like. The strength of the fiber
sheet is at least 50 kg/cm, preferably at least 100 kg/cm. When the
strength is below 50 kg/cm, the effect of reinforcing
cement/concrete can not be obtained. Generally, cement/concrete is
reinforced with the fiber sheet by simply winding the sheet around
the cement/concrete, or by sticking the fiber sheet thereto.
Otherwise, the fiber sheet under a proper tension is wound around a
bridge pier and bonded thereto, or is bonded to the base of a
bridge. The fiber sheet of the present invention can be applied by
any of the above methods.
[0090] The high strength fiber ropes of the present invention are
made of the polybenzazole fibers which are manufactured by the
above process, and the breaking strength thereof is as high as 1
GPa or more, preferably 2.75 GPa or more, still more preferably
4.10 GPa or more. Ropes having a variety of structures can be
manufactured from such fibers by any of the known methods. The
resultant ropes have so excellent durability as a tensile strength
retention of 75% or more, preferably 80% after exposed to
atmospheres of high temperatures and high humidity over long
periods of time.
[0091] The knife proof vests of the present invention are made of
laminated woven fabrics of the polybenzazole fibers. The texture of
the woven fabric may be any of plain weave, twill weave and other
weaves for ordinary fabrics. Plain weave fabrics are preferred,
since the textures thereof are hard to shift so that high knife
proof performance can be realized. The fineness of the
polybenzazole fibers of this invention is 600 dtex or less,
preferably 300 dtex or less. Advantageously, such low fineness
fibers make it possible to achieve high knife proof performance. It
is also important that the number of yarns of the woven fabric of
this invention is 30 yarns/25 mm or more, preferably 50 yarns/25 mm
or more. When the number of yarns is small, the yarns of the fabric
tend to move so that sufficient knife proof performance can not be
obtained. The weight of the fabric is 100 g/m.sup.2 or more,
preferably 150 g/m.sup.2 or more, in which range, excellent knife
proof performance can be exhibited. The fabric to be used in this
invention may be partially or fully coated or impregnated with a
resin. The knife proof vest of the present invention is made of a
lamination of such fabrics, or may be made of a plurality of such
fabrics integrally sewn with a high strength machine sewing
yarn.
[0092] The bullet proof vests of the present invention are made of
laminated fabrics of the polybenzazole fibers. The texture of the
fabric may be any of plain weave, twill weave and other weaves for
ordinary fabrics. Plain weave fabrics or twill weave fabrics are
preferred, since the texture of the fabric hardly shift, which
makes it possible to achieve high bullet proof performance. The
fineness of the polybenzazole fibers of this invention is 1,110
dtex or lower, preferably 600 dtex or lower, and the use of the
polybenzazole fibers with such a low fineness makes it easy to
achieve high bullet proof performance. It is also important that
the number of the yarns of the fabric of this invention should be
40 yarns/25 mm or less. The weight of the fabric is 200 g/cm.sup.2
or less, preferably 150 g/m.sup.2, in which range excellent bullet
proof performance can be realized. The bullet proof vest of the
present invention is made of a lamination of the above fabrics, or
may be made of the above fabrics integrally sewn with a high
strength machine sewing yarn.
BEST MODES FOR CARRYING OUT THE INVENTION
[0093] Hereinafter, the present invention will be explained in more
detail by way of Examples, which, however, should not be construed
as limiting the scope of the present invention in any way. Needless
to say, modifications of Examples within a range adapted to the
gist as described later are possible, and such modifications are
also included in the scope of the present invention.
[0094] The measuring methods in relation to Examples are conducted
as follows.
(Evaluation of Strength of Filament or Film under Atmosphere of
High Temperature and High Humidity)
[0095] The strength of a filament or a film was evaluated by
measuring the strength retentions of the filament or the film found
before and after a storage test under an atmosphere of high
temperature and high humidity. This storage test was conducted
using Humidic Chamber 1G43M manufactured by Yamato Kagakusha. A
filament or a film wound onto a paper bobbin with a diameter of 5
cm was set on the apparatus. The apparatus was continuously
operated for 100 days under an atmosphere of a temperature of
80.degree. C. and a relative humidity of 80%.
(Strength Retention)
[0096] The strengths of a filament found before and after a storage
test under an atmosphere of a high temperature and high humidity
were measured with a tension tester (RTM250 manufactured by A &
D) according to the procedure of JIS-L1013, and the tensile
strength found after the storage test was divided by the initial
tensile strength found before the storage test. The strength of a
film was determined in the same manner as above, using a sample
film with a length of 5 cm, width of 1 mm and thickness of 8.5
.mu.m.
(Evaluation of Decrease in Strength under Atmosphere of High
Temperature and High Humidity)
[0097] A decrease in the strength of a filament or a film under an
atmosphere of high temperature and high humidity was evaluated as
follows: the filament wound onto a resinous bobbin with a diameter
of 10 cm as a sample was stored in a container constantly kept at
high temperature and high humidity, and removed from the container
and subjected to a tensile test at a room temperature. The decrease
in the strength of the sample was evaluated based on the strength
retention of the sample relative to the strength thereof found
before the storage test under the atmosphere of high temperature
and high humidity. In this regard, the storage test was carried out
under an atmosphere of a temperature of 80.degree. C. and a
relative humidity of 80% for 700 hours, using Humidic Chamber 1G43M
manufactured by Yamato Kagakusha, which was perfectly shielded so
as not to permit light to pass through the container.
[0098] The strength retention was determined by measuring the
tensile strengths of the sample found before and after the storage
test, dividing the tensile strength found after the storage test by
the tensile strength found before the storage test, and multiplying
the quotient by 100. The measurement of the tensile strengths was
conducted using a tensile tester (AG-50KNG manufactured by SIMADZU
CORPORATION), according to the procedure of JIS-L1013.
(Measurement of Concentration of Phosphorus or Sodium Remaining in
Filament or Fiber)
[0099] The concentration of the residual phosphorous in a filament
or a fiber as a sample was measured using pellets obtained by
solidifying the sample, with a fluorescent X-ray spectrometer
(PW1404/DY685 manufactured by PHILIPS). The concentration of the
residual sodium was measured by the neutron-activating
analysis.
(Moisture Regain)
[0100] The moisture regain, was calculated from the weight W0 g of
a filament or fiber found before the drying and the weight W1 g of
the same filament or fiber found after the drying, according to the
following equation. The drying was carried out at a temperature of
200.degree. C. for one hour. Moisture regain
(%)=(W0-W1)/W1.times.100 (Measurement of X-Ray Meridian Diffraction
Half-Width Factor Hws)
[0101] A goniometer (Ru-200 X-ray generator, RAD-rA system,
manufactured by RIGAKU) was mounted on an apparatus as shown in
FIG. 1, which pulls a filament under a tension, and the stress
dependency of the width of (0010) diffraction lines was determined.
The apparatus was operated at an output of 40 kV.times.100 mA to
generate CuK .alpha.-rays from a copper-rotating target.
[0102] The diffraction intensity was recorded on an imaging plate
(FDL UR-V manufactured by Fuji Photo Film Co., Ltd.). The
diffraction intensity recorded was read with a digital
microluminography (PIXsysTEM manufactured by JEOL LTD.). To
precisely evaluate the half width of the resultant peak profile,
curve fitting was conducted by using a synthesis of a Gaissian
function and a Lorents function. The results were plotted relative
to the stresses applied to the filament. The spots of the data were
linearly aligned, and the half width factor (Hws) was evaluated
from the gradient of the alignment of the spots. FIG. 2 shows an
example of the graph for evaluating Hws.
(Measurement of Factor for Change of Molecular Orientation)
[0103] The apparatus as shown in FIG. 1, which applied a tension to
a filament, was mounted on a small angle X-ray scattering
apparatus, and the broadening of a peak of (200) diffraction points
in the azimuth angular direction was measured so as to measure the
elasticity decrement Er attributed to change of molecular
orientation. FIG. 3 shows an example of the graph showing the
change of molecular orientation (<sin.sup.2.phi.>).
[0104] The change of molecular orientation (<sin
.sup.2.phi.>) was calculated from the azimuth angle profile I
(.phi.) of the (200) diffraction intensity, according to the
following equation. The origin of the azimuth angle was present on
the meridian as .phi.=0. < sin 2 .times. .PHI. >= .intg. 0
.pi. .times. / .times. 2 .times. I .function. ( .PHI. ) .times. sin
3 .times. .PHI. .times. .times. d .PHI. .intg. 0 .pi. .times. /
.times. 2 .times. I .function. ( .PHI. ) .times. sin .times.
.times. .PHI. .times. .times. d .PHI. ##EQU1##
[0105] According to the theory (Polymer 21, p. 1199, 1980) proposed
by Northort, the strain (.epsilon.) of a whole of a filament can be
expressed as a synthesis of the elongation (.epsilon.c) of crystals
and contribution (.epsilon.r) of rotation:
.epsilon.=.epsilon.c+.epsilon.r
[0106] The elongation .epsilon.c of crystals can be calculated from
the elasticity Ec of the crystal and a stress .sigma., and the
contribution .epsilon.r of rotation can be calculated using the
results (shown in FIG. 3) which were measured by using
<sin.sup.2.phi.> as the function of .sigma., so as to rewrite
.epsilon. as the following equation. Herein, .phi.0 is an
orientation angle when the stress is zero; .phi. is an orientation
angle when the stress is .sigma.. .epsilon.=.sigma./Ec+(<cos
.phi.>/<cos .phi.0>-1)
[0107] The elasticity decrement Er attributed to change of
molecular orientation is defined by the following equation. In this
regard, the content of the parentheses of the second term on the
right side indicates the gradient of the tangent line of .epsilon.
when .sigma. is zero (.sigma.=0). Er = Ec - ( d d .sigma. .times.
.sigma. = 0 ) - 1 ##EQU2## (Method of Evaluating Abrasion
Resistance of Felt Material Made of Polybenzazole Fibers at High
Temperature)
[0108] A sample was abraded with an abrasion tester as shown in
FIG. 4, by bringing a rubbing material heated at 500.degree. C.
into contact with the sample under a load of 300 g/cm.sup.2, and
rotating the sample at 300 rpm under this condition. Specifically,
the sample was dipped in pure water for 10 seconds just before the
abrasion test, and then abraded for 5 hours; and the sample was
removed from the tester, again dipped in pure water for 10 seconds
and again abraded for 5 hours. This operation was repeated until
the sample had been abraded for total 20 hours. The abrasion
resistance of the sample was evaluated based on a decrease in the
weight of the sample found after the abrasion for 20 hours.
(Experiment Example)
Making of Film-like Polybenzazole
[0109] A solution (or a polymer dope) of polybenzazole in
polyphosphoric acid was sandwiched between polytetrafluoroethylene
sheets and pressed with a heat press at 175.degree. C. under a
pressure of 150 kg/cm.sup.2. After that, the resultant polymer dope
sandwiched between the polytetrafluoroethylene sheets was stretched
at 130.degree. C. in the longitudinal direction until the length of
the polymer dope became 3 times larger and in the lateral direction
until the width thereof became 3 times larger. After cooling, the
polymer dope was striped from the polytetrafluoroethylene sheets,
and washed with water until the concentration of the residual
phosphorous reached 5,000 ppm or less.
Making of Polybenzazole Filaments
[0110] Spinning was carried out so as to obtain filaments with
diameters of 11.5 .mu.m and fineness of 1.5 denier. A polymer dope
was extruded through a nozzle having 340 holes with diameters of
160 .mu.m at a spinning temperature of 150.degree. C., and the
extruded filaments were pushed into a first washing bath which was
so located as to cause the filaments to be converged at an
appropriate position to form a multifilament. A quench chamber was
located in an air gap between the nozzle and the first washing
bath, so as to elongate the filaments at a more uniform
temperature. The length of the air gap was 30 cm. The filaments
were pushed out into an air at 60.degree. C. The filament takeup
rate was 200 m/min., and the filament elongation multiplying factor
was 30. The filaments were washed with water until the
concentration of the residual phosphoric acid in the polybenzazole
filaments reached 5,000 ppm or less.
EXAMPLE 1
[0111] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 28 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of aminoguanidine bicarbonate (450 g) in water
(10 L) at 50.degree. C. for 3 hours, and dried at 80.degree. C. for
4 hours. The resultant filament was subjected to a storage test
under an atmosphere of high temperature and high humidity. The
result is shown in Table 1.
EXAMPLE 2
[0112] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 27 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of 3-amino-1,2,4-triazole (500 g) in water (10
L) at 50.degree. C. for 6 hours, and dried at 80.degree. C. for 4
hours. The resultant filament was subjected to a storage test under
an atmosphere of high temperature and high humidity. The result is
shown in Table 1.
EXAMPLE 3
[0113] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 29 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of 1,3-diphenylguanidine (500 g) in acetone (10
L) at 50.degree. C. for 10 hours, and dried at 80.degree. C. for 4
hours. The resultant filament was subjected to a storage test under
an atmosphere of high temperature and high humidity. The result is
shown in Table 1.
EXAMPLE 4
[0114] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 28 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of 1,3-bis(2-benzothiazolyl)guanidine (500 g) in
acetone (10 L) at 50.degree. C. for 9 hours, and dried at
80.degree. C. for 4 hours. The resultant filament was subjected to
a storage test under an atmosphere of high temperature and high
humidity. The result is shown in Table 1.
EXAMPLE 5
[0115] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 28 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of 2-(2-hydroxy-5-methylphenyl)benzotriazole
(500 g) in acetone (10 L) at 50C for 5 hours, and dried at
80.degree. C. for 4 hours. The resultant filament was subjected to
a storage test under an atmosphere of high temperature and high
humidity. The result is shown in Table 1.
EXAMPLE 6
[0116] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 28 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of quinazoline-2,4-dione (500 g) in acetone (10
L) at 50.degree. C. for 10 hours, and dried at 80.degree. C. for 4
hours. The resultant filament was subjected to a storage test under
an atmosphere of high temperature and high humidity. The result is
shown in Table 1.
EXAMPLE 7
[0117] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 29 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of pyrazine (500 g) in water (10 L) at
50.degree. C. for 10 hours, and dried at 80.degree. C. for 4 hours.
The resultant filament was subjected to a storage test under an
atmosphere of high temperature and high humidity. The result is
shown in Table 1.
EXAMPLE 8
[0118] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 28 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of isocyanuric acid (500 g) in DMF (10 L) at
50.degree. C. for 9 hours, and dried at 80.degree. C. for 4 hours.
The resultant filament was subjected to a storage test under an
atmosphere of high temperature and high humidity. The result is
shown in Table 1.
EXAMPLE 9
[0119] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of aniline (500 g) in water (10 L) at 50.degree.
C. for 20 hours, and dried at 80.degree. C. for 4 hours. The
resultant filament was subjected to a storage test under an
atmosphere of high temperature and high humidity. The result is
shown in Table 1.
EXAMPLE 10
[0120] A polymer dope of polyparaphenylenebenzobisoxazole (13 wt.
%) having an intrinsic viscosity of 28 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament (1,500 m) was
wound onto a bobbin. The wound filament was dipped in a bath
holding a solution of pyridine (300 g) in water (10 L) at
50.degree. C. for 10 hours, and dried at 80.degree. C. for 4 hours.
The resultant filament was subjected to a storage test under an
atmosphere of high temperature and high humidity. The result is
shown in Table 1.
COMPARATIVE EXAMPLE 1
[0121] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 28 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was spun in the same
manner as described above, and the resultant filament was washed
with water and dried at 80.degree. C. for 4 hours. The resultant
filament was subjected to a storage test under an atmosphere of
high temperature and high humidity. The result is shown in Table 1.
TABLE-US-00001 TABLE 1 Tensile Strength Retention (%) Example 1 85
Example 2 84 Example 3 82 Example 4 80 Example 5 84 Example 6 85
Example 7 85 Example 8 84 Example 9 82 Example 10 80 Comparative 45
Example 1
EXAMPLE 11
[0122] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 25 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was formed into a
film-like matter in the same manner as described above, and the
resultant film-like matter was dipped in a bath holding a solution
of aminoguanidine bicarbonate (100 g) in water (10 L) for 1 minute,
washed with water and dried at 80.degree. C. for 4 hours. The
resultant film was subjected to a storage test under an atmosphere
of high temperature and high humidity. The result is shown in Table
2.
EXAMPLE 12
[0123] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 24 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was formed into a
film-like matter in the same manner as described above, and the
resultant film-like matter was dipped in a bath holding a solution
of 3-amino-1,2,4-triazole (100 g) in water (10 L) for 1 minute,
washed with water and dried at 80.degree. C. for 4 hours. The
resultant film was subjected to a storage test under an atmosphere
of high temperature and high humidity. The result is shown in Table
2.
EXAMPLE 13
[0124] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 25 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was formed into a
film-like matter in the same manner as described above, and the
resultant film-like matter was dipped in a bath holding a solution
of isocyanuric acid (100 g) in DMF (10 L) for 1 minute, washed with
water and dried at 80.degree. C. for 4 hours. The resultant film
was subjected to a storage test under an atmosphere of high
temperature and high humidity. The result is shown in Table 2.
EXAMPLE 14
[0125] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 25 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was formed into a
film-like matter in the same manner as described above, and the
resultant film-like matter was dipped in a bath holding a solution
of pyrazine (100 g) in water (10 L) for 1 minute, washed with water
and dried at 80.degree. C. for 4 hours. The resultant film was
subjected to a storage test under an atmosphere of high temperature
and high humidity. The result is shown in Table 2.
EXAMPLE 15
[0126] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 25 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was formed into a
film-like matter in the same manner as described above, and the
resultant film-like matter was dipped in a bath holding a solution
of quinazoline-2,4-dione (100 g) in acetone (10 L) for 1 minute,
washed with water and dried at 80.degree. C. for 4 hours. The
resultant film was subjected to a storage test under an atmosphere
of high temperature and high humidity. The result is shown in Table
2.
EXAMPLE 16
[0127] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 23 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was formed into a
film-like matter in the same manner as described above, and the
resultant film-like matter was dipped in a bath holding a solution
of aniline (100 g) in water (10 L) for 1 minute, washed with water
and dried at 80.degree. C. for 4 hours. The resultant film was
subjected to a storage test under an atmosphere of high temperature
and high humidity. The result is shown in Table 2.
EXAMPLE 17
[0128] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 26 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was formed into a
film-like matter in the same manner as described above, and the
resultant film-like matter was dipped in a bath holding a solution
of pyridine (100 g) in water (10 L) for 1 minute, washed with water
and dried at 80.degree. C. for 4 hours. The resultant film was
subjected to a storage test under an atmosphere of high temperature
and high humidity. The result is shown in Table 2.
COMPARATIVE EXAMPLE 2
[0129] A polymer dope of polyparaphenylenebenzobisoxazole (12 wt.
%) having an intrinsic viscosity of 25 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in polyphosphoric
acid containing 88% of phosphorus pentaoxide was formed into a
film-like matter in the same manner as described above, and the
resultant film-like matter was washed with water and dried at
80.degree. C. for 4 hours. The resultant film was subjected to a
storage test under an atmosphere of high temperature and high
humidity. The result is shown in Table 2. TABLE-US-00002 TABLE 2
Tensile Strength Retention (%) Example 11 63 Example 12 70 Example
13 68 Example 14 66 Example 15 73 Example 16 64 Example 17 67
Example 18 68 Example 19 60 Example 20 65 Comparative 42 Example
2
[0130] As is apparent from Tables 1 and 2, the polybenzazole
filaments and films impregnated with the basic organic compounds
have high strength retensions under the atmosphere of high
temperatures and high humidity.
EXAMPLE 18
[0131] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methansulfonic acid solution, in pqlyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at 175.degree.
C. to form filaments, and the resultant filaments were then dipped
in a first washing bath which was so located that the filaments
could be converged at an appropriate position into a multifilament,
and solidified. A quench chamber was provided in an air gap between
the nozzle and the first washing bath, so as to elongate the
filaments at a more uniform temperature. The quenching temperature
was 60.degree. C. After that, the polybenzazole filaments were
washed with water until the concentration of the residual
phosphorus in the filaments reached 5,000 ppm or less, and were
wound onto a paper cylinder without drying them. The takeup rate
was 200 m/min.,; the spinning elongation multiplying factor was 40;
and the wound filament was 1,500 m. The filament thus wound had a
fineness of 1.5 dpf (denier/filament) as a monofilament, a diameter
of 11.5 .mu.m and a moisture regain of 50%.
[0132] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
again wound onto a resinous bobbin without drying the same. The
wound filament had a moisture regain of 50%. The wound filament was
dipped in a bath holding a solution of aminoguanidine hydrogen
carbonate (30 g) in water (12 L) at an ordinary temperature
(20.degree. C.) for 3 hours, and then removed from the bath and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 3,800
ppm, and that of sodium, 2,300 ppm. The molar ratio of Na/P was
0.82. The filament had a strength retention of 86% after the
storage test under an atmosphere of high temperature and high
humidity.
EXAMPLE 19
[0133] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0134] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
again wound onto a resinous bobbin without drying the same. The
wound filament had a moisture regain of 50%. The wound filament was
dipped in a bath holding a solution of 3-amino-1,2,4-triazole (30
g) in water (12 L) at an ordinary temperature (20.degree. C.) for 3
hours, and then removed from the bath and dried at 80.degree. C.
for 4 hours. The concentrations of the residual phosphorous and
sodium in the resultant filament were measured. As a result, the
concentration of phosphorus was 3,600 ppm, and that of sodium,
2,000 ppm. The molar ratio of Na/P was 0.75. The filament had a
strength retention of 87% after the storage test under an
atmosphere of high temperature and high humidity.
EXAMPLE 20
[0135] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0136] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
again wound onto a porous resinous bobbin without drying the same.
The wound filament had a moisture regain of 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 4, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The filament had a strength retention of
90% after the storage test under an atmosphere of high temperature
and high humidity.
EXAMPLE 21
[0137] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0138] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
again wound onto a porous resinous bobbin without drying the same.
The wound filament had a moisture regain of 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 48 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,200 ppm, and that of sodium, 290 ppm. The molar
ratio of Na/P was 0.33. The filament had a strength retention of
92% after the storage test under an atmosphere of high temperature
and high humidity.
EXAMPLE 22
[0139] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0140] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
again wound onto a porous resinous bobbin without drying the same.
The wound filament had a moisture regain of 50%. A solution of
m-phenylenediamine (4 g) in water (12 L) was poured into an
apparatus shown in FIG. 5, and the wound filament was put in the
solution, which was then circulated at an ordinary temperature
(20.degree. C.) for 48 hours. Then, the solution was replaced with
pure water, and the pure water was circulated at an ordinary
temperature (20.degree. C.) for one hour. After that, the wound
filament was removed from the apparatus and dried at 80.degree. C.
for 4 hours. The circulations of the liquids were carried out while
an air was being supplied into the liquids. The concentrations of
the residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 1,400
ppm, and that of sodium, 280 ppm. The molar ratio of Na/P was 0.27.
The filament had a strength retention of 95% after the storage test
under an atmosphere of high temperature and high humidity.
EXAMPLE 23
[0141] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0142] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
again wound onto a porous resinous bobbin without drying the same.
The wound filament had a moisture regain of 50%. A solution of
m-phenylenediamine (3.2 g) and p-phenylenediamine (0.8 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 48 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,200 ppm, and that of sodium, 360 ppm. The molar
ratio of Na/P was 0.40. The filament had a strength retention of
93% after the storage test under an atmosphere of high temperature
and high humidity.
EXAMPLE 24
[0143] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0144] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
again wound onto a porous resinous bobbin without drying the same.
The wound filament had a moisture regain of 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with an aqueous NaOH solution with a ratio of
0.01 mol/L, and the aqueous NaOH solution was circulated at an
ordinary temperature (20.degree. C.) for one hour. After that, the
wound filament was removed from the apparatus and dried at
80.degree. C. for 4 hours. The circulations of the liquids were
carried out while an air was being supplied into the liquids. The
concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,400 ppm, and that of sodium, 130 ppm. The molar
ratio of Na/P was 1.25. The filament had a strength retention of
93% after the storage test under an atmosphere of high temperature
and high humidity.
EXAMPLE 25
[0145] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0146] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
again wound onto a porous resinous bobbin without drying the same.
The wound filament had a moisture regain of 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at
80.degree. C. for 8 hours. Then, the solution was replaced with
pure water, and the pure water was circulated at an ordinary
temperature (20.degree. C.) for one hour. After that, the wound
filament was removed from the apparatus and dried at 80.degree. C.
for 4 hours. The circulations of the liquids were carried out while
an air was being supplied into the liquids. The concentrations of
the residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 900 ppm,
and that of sodium, 200 ppm. The molar ratio of Na/P was 0.30. The
filament had a strength retention of 92% after the storage test
under an atmosphere of high temperature and high humidity.
EXAMPLE 26
[0147] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0148] The wound filament was again wound onto a porous resinous
bobbin without drying the same. The wound filament had a moisture
regain of 50%. A solution of m-phenylenediamine (2.8 g) and
p-phenylenediamine (1.2 g) in water (12 L) was poured into an
apparatus shown in FIG. 5, and the wound filament was put in the
solution, which was then circulated at an ordinary temperature
(20.degree. C.) for 24 hours. Then, the solution was replaced with
pure water, and the pure water was circulated at an ordinary
temperature (20.degree. C.) for one hour. After that, the wound
filament was removed from the apparatus and dried at 80.degree. C.
for 4 hours. The circulations of the liquids were carried out while
an air was being supplied into the liquids. The concentrations of
the residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 1,700
ppm, and that of sodium, 0 ppm. The molar ratio of Na/P was 0. The
filament had a strength retention of 89% after the storage test
under an atmosphere of high temperature and high humidity.
COMPARATIVE EXAMPLE 3
[0149] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0150] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The filament had a strength retention of 82% after the
storage test under an atmosphere of high temperature and high
humidity.
COMPARATIVE EXAMPLE 4
[0151] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0152] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds and washed with water for 30 seconds. The
wound filament was then dried until the moisture regain thereof
reached 10%, and again wound onto a resinous bobbin. The wound
filament was dipped in a bath holding a solution of aminoguanidine
hydrogen carbonate (30 g) in water (12 L) at an ordinary
temperature (20.degree. C.) for 3 hours. Then, the wound filament
was removed from the bath and dried at 80.degree. C. for 4 hours.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 4,000 ppm, and that of sodium, 2,400 ppm. The molar
ratio of Na/P was 0.81. The filament had a strength retention of
78% after the storage test under an atmosphere of high temperature
and high humidity.
COMPARATIVE EXAMPLE 5
[0153] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0154] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds. The
wound filament was then dried until the moisture regain reached 10%
and wound onto a porous resinous bobbin. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 3,600 ppm, and that of sodium, 2,200 ppm. The molar
ratio of Na/P was 0.82. The filament had a strength retention of
79% after the storage test under an atmosphere of high temperature
and high humidity.
COMPARATIVE EXAMPLE 6
[0155] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0156] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
wound filament had a moisture regain of 50%. The wound filament was
allowed to contact a solution of m-phenylenediamine (2.8 g) and
p-phenylenediamine (1.2 g) in water (12 L) for 60 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,400
ppm, and that of sodium, 3,200 ppm. The molar ratio of Na/P was
0.98. The filament had a strength retention of 81% after the
storage test under an atmosphere of high temperature and high
humidity.
COMPARATIVE EXAMPLE 7
[0157] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0158] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
wound filament had a moisture regain of 50%. The wound filament was
allowed to contact a solution of m-phenylenediamine (2.8 g) and
p-phenylenediamine (1.2 g) in water (50 g) for 60 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,600
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.97. The filament had a strength retention of 81% after the
storage test under an atmosphere of high temperature and high
humidity.
COMPARATIVE EXAMPLE 8
[0159] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0160] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
p-phenylenediamine (4 g) in water (12 L) was poured into an
apparatus shown in FIG. 5, and the wound filament was put in the
solution, which was then circulated at an ordinary temperature
(20.degree. C.) for 48 hours. Then, the solution was replaced with
pure water, and the pure water was circulated at an ordinary
temperature (20.degree. C.) for one hour. After that, the wound
filament was removed from the apparatus and dried at 80.degree. C.
for 4 hours. The circulations of the liquids were carried out while
an air was being supplied into the liquids. The concentrations of
the residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 1,400
ppm, and that of sodium, 320 ppm. The molar ratio of Na/P was 0.31.
The filament had a strength retention of 83% after the storage test
under an atmosphere of high temperature and high humidity.
COMPARATIVE EXAMPLE 9
[0161] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 18.
[0162] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (1.2 g) and p-phenylenediamine (2.8 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 48 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,200 ppm, and that of sodium, 240 ppm. The molar
ratio of Na/P was 0.27. The filament had a strength retention of
84% after the storage test under an atmosphere of high temperature
and high humidity.
[0163] The foregoing results are summarized in Table 3. As is
apparent from Table 3, the polybenzazole filaments of Examples had
very high strength retentions after exposed to the atmospheres of
high temperatures and high humidity, as compared with the filaments
of Comparative Examples. TABLE-US-00003 TABLE 3 Conditions for
washing, neutralizing and washing Neutralization Washing Con- Con-
time after centra- centra- Molar Break- Strength NaOH neutral- tion
tion ratio ing reten- concen- Time ization of P of Na of strength
tion Hws Er tration Sec. Sec. ppm ppm Na/P Gpa % .degree./GPa Gpa
Ex. 18 1% 10 30 3800 2300 0.82 5.8 86 0.25 24 Ex. 19 1% 10 30 3600
2000 0.75 5.8 87 0.27 22 Ex. 20 1% 10 30 1900 760 0.54 5.8 90 0.18
21 Ex. 21 1% 10 30 1200 290 0.33 5.7 92 0.13 17 Ex. 22 1% 10 30
1400 280 0.27 5.7 95 0.20 21 Ex. 23 1% 10 30 1200 360 0.40 5.7 93
0.22 24 Ex. 24 1% 10 30 1400 1300 1.25 5.7 93 0.15 18 Ex. 25 1% 10
30 900 200 0.30 5.3 92 0.20 24 Ex. 26 -- 0 0 1700 0 0 5.5 89 0.19
20 C. Ex. 3 1% 10 30 4700 3300 0.95 6.0 82 0.36 36 C. Ex. 4 1% 10
30 4000 2400 0.81 5.8 78 0.37 40 C. Ex. 5 1% 10 30 3600 2200 0.82
5.9 79 0.39 36 C. Ex. 6 1% 10 30 4400 3200 0.98 5.9 81 0.35 37 C.
Ex. 7 1% 10 30 4600 3300 0.97 5.6 81 0.37 42 C. Ex. 8 1% 10 30 1400
320 0.31 5.6 83 0.31 32 C. Ex. 9 1% 10 30 1200 240 0.27 5.7 84 0.32
34 Treating conditions Moisture Concen- regain tration of Temp.
before treating Reagent Ratio Time .degree. C. treatment liquid Ex.
18 Aminoguanidine -- 3 hr. 20 50% 2500 ppm hydrogen carbonate Ex.
19 3-Amino-1,2,4-triazole -- 3 hr. 20 50% 2500 ppm Ex. 20
p-Phenylenediamine/ 3/7 24 hr 20 50% 330 ppm m-phenylenediamine Ex.
21 p-Phenylenediamine/ 3/7 48 hr. 20 50% 330 ppm m-phenylenediamine
Ex .22 p-Phenylenediamine/ 0/10 48 hr. 20 50% 330 ppm
m-phenylenediamine Ex. 23 p-Phenylenediamine/ 2/8 48 hr. 20 50% 330
ppm m-phenylenediamine Ex. 24 p-Phenylenediamine/ 3/7 24 hr. 20 50%
330 ppm m-phenylenediamine Ex. 25 p-Phenylenediamine/ 3/7 8 hr. 80
50% 330 ppm m-phenylenediamine Ex. 26 p-Phenylenediamine/ 3/7 24
hr. 20 50% 330 ppm m-phenylenediamine C. Ex. 3 -- -- -- -- -- -- C.
Ex. 4 Aminoguanidine -- 3 hr. 20 10% 2500 ppm hydrogen carbonate C.
Ex. 5 p-Phenylenediamine/ 3/7 24 hr 20 10% 330 ppm
m-phenylenediamine C. Ex. 6 p-Phenylenediamine/ 3/7 60 sec. 20 50%
330 ppm m-phenylenediamine C. Ex. 7 p-Phenylenediamine/ 3/7 60 sec.
20 50% 8% m-phenylenediamine C. Ex. 8 p-Phenylenediamine/ 10/0 48
hr. 20 50% 330 ppm m-phenylenediamine C. Ex. 9 p-Phenylenediamine/
7/3 48 hr. 20 50% 330 ppm m-phenylenediamine
EXAMPLE 27
[0164] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. After that, the filaments were washed
with water until the concentration of the residual phosphorous in
the polybenzazole filaments reached 5,000 ppm or less, and were
wound onto a paper cylinder without drying the same. The takeup
rate was 200 m/min.; the spinning elongation multiplying factor was
40; and the length of the filament wound was 1,500 m. The wound
filament had a fineness of 1.5 dpf (denier/filament) as a
monofilament, and a diameter of 11.5 .mu.m and a moisture regain of
50%.
[0165] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. Spinning oil was applied to the resultant
filaments, which were doubled to form a tow having a fineness of
30,000 denier. The tow was crimped with a push-on crimper having
rolls with widths of 20 mm. The crimped tow was cut with a rotary
cutter, into staple fibers with given lengths of 44 mm. The staple
fibers thus obtained had a strength retention of 90% after the
storage test under an atmosphere of high temperature and high
humidity.
COMPARATIVE EXAMPLE 10
[0166] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 27.
[0167] The wound filament was neutralized with a 1% aqueous NabH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3.300 ppm. The molar ratio of Na/P was
0.95. Spinning oil was applied to the resultant filaments, which
were doubled to form a tow having a fineness of 30,000 denier. The
tow was crimped with a push-on crimper having rolls with widths of
20 mm. The crimped tow was cut with a rotary cutter, into staple
fibers with given lengths of 44 mm. The staple fibers thus obtained
had a strength retention of 82% after the storage test under an
atmosphere of high temperature and high humidity.
COMPARATIVE EXAMPLE 11
[0168] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 27.
[0169] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried until the moisture regain thereof reached 10%, and again
wound onto a porous resinous bobbin. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 3,600 ppm, and that of sodium, 2,200 ppm. The molar
ratio of Na/P was 0.82. Spinning oil was applied to the resultant
filaments, which were doubled to form a tow having a fineness of
30,000 denier. The tow was crimped with a push-on crimper having
rolls with widths of 20 mm. The crimped tow was cut with a rotary
cutter, into staple fibers with given lengths of 44 mm. The staple
fibers thus obtained had a strength retention of 79% after the
storage test under an atmosphere of high temperature and high
humidity.
[0170] The foregoing results are summarized in Table 4. As is
apparent from Table 4, the polybenzazole staple fibers of Example
had a very high strength retention after exposed to the atmosphere
of high temperature and high humidity, as compared with the staple
fibers of Comparative Examples. TABLE-US-00004 TABLE 4 Conditions
for washing, neutralization and washing Con- Con- Neutralization
Washing centra- centra- Molar Break- Strength NaOH neutral- tion
tion ratio ing reten- concen- Time ization of P of Na of strength
tion Hws Er tration Sec. Sec. ppm ppm Na/P GPa % .degree./GPa Gpa
Ex. 27 1% 10 30 1900 760 0.54 5.8 90 0.18 21 C. Ex. 10 1% 10 30
4700 3300 0.95 6.0 82 0.36 36 C. Ex. 11 1% 10 30 3600 2200 0.82 5.9
79 0.39 36 Treating conditions Moisture Concen- regain tration of
Temp. before treating Reagent Ratio Time .degree. C. treatment
liquid Ex. 27 p-Phenylenediamine 3/7 24 hr. 20 50% 330 ppm C. Ex.
10 -- -- -- -- -- -- C. Ex. 11 p-Phenylenediamine 3/7 24 hr 20 10%
330 ppm
EXAMPLE 28
[0171] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments: The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0172] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The resultant polybenzazole filaments were
cut into staple fibers with lengths of 51 mm, which were then
twisted at a twist coefficient of 3.5 to make a spun yarn having a
cotton yarn count of 20 Ne. The spun yarn thus obtained had a
tensile strength of 9.8 cN/dtex, and had a strength retention of
77% after the storage test under an atmosphere of high temperature
and high humidity (80.degree. C. and 80 RH %)
COMPARATIVE EXAMPLE 12
[0173] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 28.
[0174] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The resultant polybenzazole filaments were cut into staple
fibers with lengths of 51 mm, which were then twisted at a twist
coefficient of 3.5 to make a spun yarn having a cotton yarn count
of 20 Ne. The spun yarn thus obtained had a tensile strength of 9.1
cN/dtex, and had a strength-retention of 60% after the storage test
under an atmosphere of high temperature and high humidity
(80.degree. C. and 80 RH %).
EXAMPLE 29
[0175] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0176] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The resultant polybenzazole filaments were
cut into staple fibers with lengths of 51 mm, which were then
twisted at a twist coefficient of 3.5 to make a spun yarn having a
cotton yarn count of 20 Ne. Two such spun yarns were twisted to
make a two folded yarn having a yarn count of 20/2 Ne. The two
folded yarns thus obtained were woven to make a 2/1 twill fabric
which was filled with 68 two folded yarns/inch in the vertical
direction and filled with 60 two folded yarns/inch in the lateral
direction. The tensile strength of the resultant twill fabric in
the vertical direction was 4,260 N/3 cm. The twill fabric had a
strength retention of 78% after the storage test under an
atmosphere of high temperature and high humidity (80.degree. C. and
80 RH %).
EXAMPLE 30
[0177] The spun yarns having a yarn count of 20/1Ne obtained in
Example 29 were knitted to make a round braid which had 68
stitches/inch in the vertical direction and 29 stitches/inch in the
lateral direction. The tensile strength of the round braid in the
vertical direction was 1,530 N/5 cm. The round braid had a strength
retention of 76% after the storage test under an atmosphere of high
temperature and high humidity (80.degree. C. and 80 RH %).
COMPARATIVE EXAMPLE 13
[0178] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 29.
[0179] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The resultant polybenzazole filaments were cut into staple
fibers with lengths of 51 mm, which were then twisted at a twist
coefficient of 3.5 to make a spun yarn having a cotton yarn count
of 20/1 Ne. Two such spun yarns were twisted to make a two folded
yarn having a yarn count of 20/2 Ne. The two folded yarns thus
obtained were woven to make a 2/1 twill fabric which was filled
with 68 two folded yarns/inch in the vertical direction and filled
with 60 two folded yarns/inch in the lateral direction. The tensile
strength of the resultant twill fabric in the vertical direction
was 4,280 N/3 cm. The twill fabric had a strength retention of 59%
after the storage test under an atmosphere of high temperature and
high humidity (80.degree. C. and 80 RH %)
COMPARATIVE EXAMPLE 14
[0180] The spun yarns having a yarn count of 20/1Ne obtained in
Comparative Example 13 were knitted to make a round braid which had
68 stitches/inch in the vertical direction and 29 stitches/inch in
the lateral direction. The tensile strength of the round braid in
the vertical direction was 1,490 N/S cm. The round braid had a
strength retention of 62% after the storage test under an
atmosphere of high temperature and high humidity (80.degree. C. and
80 RH %)
EXAMPLE 31
[0181] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0182] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54.
[0183] Spinning oil was applied to the resultant filaments, which
were then doubled to make a tow having a thickness of 30,000
deniers. The tow was crimped with a push-on crimper having rolls
with widths of 20 mm. The crimped tow was cut with a rotary cutter,
into staple fibers with lengths of 44 mm, which were then opened
with an opener to make a web having a weight of 200 g/m.sup.2 with
a roller card. A plurality of webs thus obtained were laminated and
subjected to needle punching to obtain a felt having a thickness of
9.8 mm and a weight of 2,700 g/m.sup.2. The abrasion resistance of
the felt under an atmosphere of high temperature was evaluated. As
a result, the decrease in the weight of the felt due to abrasion
was 3.1 mg/cm.sup.2.
COMPARATIVE EXAMPLE 15
[0184] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 31.
[0185] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95.
[0186] The filaments thus obtained were processed in the same
manner as in Example 31 to obtain a felt having a thickness of 10.2
mm and a weight of 2,800 g/m.sup.2. The abrasion resistance of the
felt under an atmosphere of high temperature was evaluated. As a
result, the decrease in the weight of the felt due to abrasion was
3.7 mg/cm.sup.2.
COMPARATIVE EXAMPLE 16
[0187] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 31.
[0188] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried until the moisture regain thereof reached 10%. Then, the
filament was wound onto a porous resinous bobbin. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 3,600 ppm, and that of sodium, 2,200 ppm. The molar
ratio of Na/P was 0.82.
[0189] The filaments thus obtained were processed in the same
manner as in Example 31 to obtain a felt having a thickness of 9.9
mm and a weight of 2,700 g/m.sup.2. The abrasion resistance of the
felt under an atmosphere of high temperature was evaluated. As a
result, the decrease in the weight of the felt due to the abrasion
was 3.8 mg/cm.sup.2.
[0190] The foregoing results are summarized in Table 5. As is
apparent from Table 5, the felt material made of the polybenzazole
filaments of Example had a very high abrasion resistance under the
atmosphere of high temperature and high humidity, as compared with
the felt materials made of the filaments of Comparative Examples.
TABLE-US-00005 TABLE 5 Conditions for washing, neutralization and
washing Washing Neutralization time after Concen- Concen- Molar
Break- Strength NaOH neutral- tration tration ratio ing reten-
concen- Time ization of P of Na of strength tion Hws Er tration
Sec. Sec. ppm ppm Na/P GPa % .degree./GPa Gpa Ex. 31 1% 10 30 1900
760 0.54 5.8 90 0.18 21 C. Ex. 15 1% 10 30 4700 3300 0.95 6.0 82
0.36 36 C. Ex. 16 1% 10 30 3600 2200 0.82 5.9 79 0.39 36 Treating
conditions Abrasion resistance at high Moisture Concen- temp.
regain tration (felt) Temp. before of Decrease Reagent Ratio Time
.degree. C. treatment liquid in weight Ex. 31 p-Phenylenediamine
3/7 24 hr. 20 50% 330 3.1 mg/cm.sup.2 C. Ex. 15 -- -- -- -- -- --
3.7 mg/cm.sup.2 C. Ex. 16 p-Phenylenediamine 3/7 24 hr 20 10% 330
3.8 mg/cm.sup.2
[0191] Since the present invention can provide felt materials made
of polybenzazole fibers which can sufficiently maintain the
strengths even after exposed to atmospheres of high temperatures
and high humidity over long periods of time, the felt materials of
the present invention can be effectively used to convey hot
products which retain heat of, particularly 300.degree. C. or
higher, especially 400.degree. C. or higher, manufactured in the
field of molding metals such as aluminum, iron, copper, etc. and
ceramics.
EXAMPLE 32
[0192] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and soldified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0193] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The filament had a strength retention of
90% after the storage test under an atmosphere of high temperature
and high humidity.
COMPARATIVE EXAMPLE 17
[0194] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 32.
[0195] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The filament had a strength retention of 82% after the
storage test under an atmosphere of high temperature and high
humidity.
EXAMPLE 33
[0196] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0197] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The filament had a strength retention of
90% after the storage test under an atmosphere of high temperature
and high humidity.
[0198] Six polybenzazole filaments thus obtained were Z-wise
twisted at 32T/10 cm to make a Z twist yarn. Two such Z twist yarns
were S-wise twisted at 32T/10 cm to make a crude cord. Then, the
crude cord was subjected to a two-stage dipping treatment to make a
dip cord. The first dipping treatment was carried out at
240.degree. C., using an aqueous dispersion of an epoxy resin, and
the second dipping treatment was carried out at 235.degree. C.,
using a RFL liquid. The strength of the dip cord was 649 N. This
dip cord was excellent in strength retention as high as 81% under
an atmosphere of high temperature and high humidity.
COMPARATIVE EXAMPLE 18
[0199] The procedure up to the step of washing a polybenzazole
filament until the concentration of the residual phosphorus reached
5,000 ppm or less and winding the same onto a paper cylinder
without drying was repeated in the same manner as in Example
33.
[0200] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The filament had a strength retention of 82% after the
storage test under an atmosphere of high temperature and high
humidity.
[0201] Six polybenzazole filaments thus obtained were Z-wise
twisted at 32T/10 cm to make a Z twist yarn. Two such Z twist yarns
were S-wise twisted at 32T/10 cm to make a crude cord. Then, the
crude cord was subjected to a two-stage dipping treatment to make a
dip cord. The first dipping treatment was carried out at
240.degree. C., using an aqueous dispersion of an epoxy resin, and
the second dipping treatment was carried out at 235.degree. C.,
using a RFL liquid. The strength of the dip cord was 653 N. This
dip cord had a strength retention of 56% under an atmosphere of
high temperature and high humidity, which was inferior to that of
the dip cord of Example 33.
[0202] According to the present invention, it is possible to
provide a cord for reinforcing rubber, which is made of twisted
polybenzazole filaments having a high strength retention even after
exposed to an atmosphere of high temperature and high humidity over
a long period of time.
EXAMPLE 34
[0203] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0204] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The filament had a strength retention of
90% after the storage test under an atmosphere of high temperature
and high humidity.
[0205] Twelve polybenzazole filaments thus obtained were twisted at
20T/1 m to make a doubled twist yarn having a fineness of 3,000
denier. Sixteen doubled twist yarns were braided to make a braid.
The braid was impregnated with an epoxy resin and set hard, to
thereby provide a rod with a diameter of 2 mm, containing 16% of
the resin. The decrease in the strength of the rod under an
atmosphere of high temperature and high humidity was measured. As a
result, the strength retention of the rod was as high as 87%.
COMPARATIVE EXAMPLE 19
[0206] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 34.
[0207] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The filament had a strength retention of 82% after the
storage test of high temperature and high humidity.
[0208] Twelve polybenzazole filaments thus obtained were twisted at
20T/1 m to make a doubled twist yarn having a fineness of 3,000
denier. Sixteen doubled twist yarns were braided to make a braid.
The braid was impregnated with an epoxy resin and set hard, to
thereby provide a rod with a diameter of 2 mm, containing 16% of
the resin. The decrease in the strength of the rod under an
atmosphere of high temperature and high humidity was measured. As a
result, the strength retention of the rod was 73% which was
inferior to that of the rod of Example 34.
[0209] According to the present invention, it is possible to
provide a polybenzazole fiber rod for reinforcing cement and
concrete, which can sufficiently maintain the strength even after
exposed to an atmosphere of high temperature and high humidity over
a long period of time.
EXAMPLE 35
[0210] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0211] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The filament had a strength retention of
90% after subjected to a storage test of high temperature and high
humidity.
[0212] Twelve polybenzazole filaments thus obtained were twisted at
20T/1 m to make a doubled twist yarn having a fineness of 3,000
denier. The doubled twist yarns were woven with a rapier loom to
make a plain weave fabric which was filled with 17 warp yarns/inch
and 17 weft yarns/inch. The weight of the fabric was 485 g/m.sup.2.
The tensile strength of the fabric in the warp direction was 620
kg/cm. The decrease in the strength of the fabric under an
atmosphere of high temperature and high humidity was measured. As a
result, the strength retention was as high as 82%.
COMPARATIVE EXAMPLE 20
[0213] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 35.
[0214] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The filament had a strength retention of 82% after subjected
to the storage test under an atmosphere of high temperature and
high humidity.
[0215] Twelve polybenzazole filaments thus obtained were twisted at
20T/1 m to make a doubled twist yarn having a fineness of 3,000
denier. The doubled twist yarns were woven with a rapier loom to
make a plain weave fabric which was filled with 17 warp yarns/inch
and 17 weft yarns/inch. The weight of the fabric was 490 g/m.sup.2.
The tensile strength of the fabric in the warp direction was 637
kg/cm. The decrease in the strength of the fabric under an
atmosphere of high temperature and high humidity was measured. As a
result, the strength retention was 65%, which was inferior to that
of the fabric of Example 35.
[0216] According to the present invention, it is possible to
provide a polybenzazole fiber sheet for reinforcing cement and
concrete, which can sufficiently maintain the strength even after
exposed to an atmosphere of high temperature and high humidity over
a long period of time.
EXAMPLE 36
[0217] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0218] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The filament had a strength retention of
90% after the storage test under an atmosphere of high temperature
and high humidity.
[0219] The resultant filament yarns were woven with a rapier loom
to make a plain weave fabric which was filled with 60 warp yarns/25
mm and 60 weft yarns/25 mm. The weight of the fabric was 138
g/m.sup.2. The tensile strength of the fabric in the warp direction
was 2,660 N/3 cm. The decrease in the strength of the fabric under
an atmosphere of high temperature and high humidity, and the
decrease in strength of the fabric which had been subjected to a
light resistance test were measured. As a result, the strength
retentions thereof were as high as 82% and 62%, respectively.
COMPARATIVE EXAMPLE 21
[0220] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 36.
[0221] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The filament had a strength retention of 82% after the
storage test under an atmosphere of high temperature and high
humidity.
[0222] The resultant filament yarns were woven with a rapier loom
to make a plain weave fabric which was filled with 50 warp yarns/25
mm and 50 weft yarns/25 mm. The weight of the fabric was 135
g/m.sup.2. The tensile strength of the fabric in the warp direction
was 2,760 N/3 cm. The decrease in the strength of the fabric under
an atmosphere of high temperature and high humidity, and the
decrease in strength of the fabric which had been subjected to a
light resistance test were measured. As a result, the strength
retentions thereof were 63% and 47%, respectively, which were
inferior to those of the fabric of Example 36.
[0223] According to the present invention, it is possible to
provide a knife proof vest made of the polybenzazole filaments
which can sufficiently maintain the strength even after exposed to
an atmosphere of high temperature and high humidity over a long
period of time, and which also shows high durability, i.e., a high
strength retention after exposed to xenon irradiation.
EXAMPLE 37
[0224] A polymer dope of polyparaphenylenebenzobisoxazole (14 wt.
%) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, in polyphosphoric
acid containing 84.3% of phosphorus pentaoxide was extruded through
a nozzle having 166 holes with diameters of 0.18 mm at a spinning
temperature of 175.degree. C. to form filaments. The filaments were
dipped in a first washing bath which was so located as to cause the
filaments to be converged at an appropriate position to form a
multifilament, and solidified. A quench chamber was located in an
air gap between the nozzle and the first washing bath, so as to
elongate the filaments at a more uniform temperature. The quench
temperature was 60.degree. C. The filaments were washed with water
until the concentration of the residual phosphorous in the
polybenzazole filaments reached 5,000 ppm or less, and were wound
onto a paper cylinder without drying the same. The takeup rate was
200 m/min.; the spinning elongation multiplying factor was 40; and
the length of the filament wound was 1,500 m. The filament wound
had a fineness of 1.5 dpf (denier/filament) as a monofilament, and
a diameter of 11.5 .mu.m and a moisture regain of 50%.
[0225] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
wound onto a porous resinous bobbin without drying the same. The
moisture regain of the wound filament was 50%. A solution of
m-phenylenediamine (2.8 g) and p-phenylenediamine (1.2 g) in water
(12 L) was poured into an apparatus shown in FIG. 5, and the wound
filament was put in the solution, which was then circulated at an
ordinary temperature (20.degree. C.) for 24 hours. Then, the
solution was replaced with pure water, and the pure water was
circulated at an ordinary temperature (20.degree. C.) for one hour.
After that, the wound filament was removed from the apparatus and
dried at 80.degree. C. for 4 hours. The circulations of the liquids
were carried out while an air was being supplied into the liquids.
The concentrations of the residual phosphorous and sodium in the
resultant filament were measured. As a result, the concentration of
phosphorus was 1,900 ppm, and that of sodium, 760 ppm. The molar
ratio of Na/P was 0.54. The filament had a strength retention of
90% after the storage test under an atmosphere of high temperature
and high humidity.
[0226] Two polybenzazole filaments thus obtained were doubled but
not twisted, to make a yarn with a thickness of 555 dtex. The yarns
thus obtained were woven with a rapier loom to make a plain weave
fabric filled with 30 warp yarns/inch and 30 weft yarns/inch. The
weight of the fabric was 135 g/m.sup.2. The tensile strength of the
fabric in the warp direction was 616 N/3 cm. The decrease in the
strength of the fabric under an atmosphere of high temperature and
high humidity, and the decrease in the strength of the fabric which
had been subjected to a light exposure test were measured. As a
result, the strength retentions of the fabric were as high as 82%
and as high as 62%, respectively.
COMPARATIVE EXAMPLE 22
[0227] The procedure up to the step of washing a polybenzazole
filament with water until the concentration of the residual
phosphorus reached 5,000 ppm or less and winding the same onto a
paper cylinder without drying was repeated in the same manner as in
Example 37.
[0228] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and washed with water for 30 seconds, and
dried at 80.degree. C. for 4 hours. The concentrations of the
residual phosphorous and sodium in the resultant filament were
measured. As a result, the concentration of phosphorus was 4,700
ppm, and that of sodium, 3,300 ppm. The molar ratio of Na/P was
0.95. The filament had a strength retention of 82% after the
storage test under an atmosphere of high temperature and high
humidity.
[0229] Two polybenzazole filaments thus obtained were doubled but
not twisted, to make a yarn with a thickness of 555 dtex. The yarns
thus obtained were woven with a rapier loom to make a plain weave
fabric filled with 30 warp yarns/inch and 30 weft yarns/inch. The
weight of the fabric was 133 g/m.sup.2. The tensile strength of the
fabric in the warp direction was 5,740 N/3 cm. The decrease in the
strength of the fabric under an atmosphere of high temperature and
high humidity, and the decrease in the strength of the fabric which
had been subjected to a light exposure test were measured. As a
result, the strength retentions of the fabric were 63% and 47%,
respectively, which were inferior to those of the fabric of Example
37.
[0230] According to the present invention, it is possible to
provide a bullet proof vest made of the polybenzazole filaments
which can sufficiently maintain the strength even after exposed to
an atmosphere of high temperature and high humidity over a long
period of time, and which also shows high durability, i.e., a high
strength retention after exposed to xenon irradiation.
INDUSTRIAL APPLICABILITY
[0231] Since the compositions, the fibers or filaments and the
films according to the present invention, and the products made
thereof have high strength retentions even after exposed to
atmospheres of high temperatures and high humidity over long
periods of time, it is possible to markedly expand the applicable
fields therefor, and thus, they contribute much to the
industries.
* * * * *