U.S. patent application number 10/580400 was filed with the patent office on 2007-05-10 for polybenzazole fiber and article comprising the same.
Invention is credited to Yukihiro Abe, Kohei Kiriyama, Hiroki Murase.
Application Number | 20070104948 10/580400 |
Document ID | / |
Family ID | 34682474 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070104948 |
Kind Code |
A1 |
Kiriyama; Kohei ; et
al. |
May 10, 2007 |
Polybenzazole fiber and article comprising the same
Abstract
The present invention relates to polybenzazole fibers which can
still have high durability against atmospheres of high temperatures
and high humidity even after yarns made thereof have had kink bands
therein due to the damages in the course of post-processing for
making woven fabrics, knitted fabrics, braids, ropes and cords. The
invention also relates to articles comprising the polybenzazole
fibers, particularly spun yarns, rubber-reinforcing materials,
fiber-reinforced composite materials, woven or knitted fabrics,
knife-proof materials or bullet-proof vests, ropes and sail
cloths.
Inventors: |
Kiriyama; Kohei; (Otsu,
JP) ; Murase; Hiroki; (Otsu, JP) ; Abe;
Yukihiro; (Otsu, JP) |
Correspondence
Address: |
KENYON & KENYON LLP
1500 K STREET N.W.
SUITE 700
WASHINGTON
DC
20005
US
|
Family ID: |
34682474 |
Appl. No.: |
10/580400 |
Filed: |
December 9, 2004 |
PCT Filed: |
December 9, 2004 |
PCT NO: |
PCT/JP04/18392 |
371 Date: |
May 24, 2006 |
Current U.S.
Class: |
428/364 |
Current CPC
Class: |
Y10T 428/2913 20150115;
D01F 6/74 20130101 |
Class at
Publication: |
428/364 |
International
Class: |
D02G 3/00 20060101
D02G003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 11, 2003 |
JP |
2003-412681 |
Dec 22, 2003 |
JP |
2003-424648 |
Dec 22, 2003 |
JP |
2003-424649 |
Dec 22, 2003 |
JP |
2003-424650 |
Dec 22, 2003 |
JP |
2003-424651 |
Dec 22, 2003 |
JP |
2003-424652 |
Dec 22, 2003 |
JP |
2003-424653 |
Dec 22, 2003 |
JP |
2003-424654 |
Dec 22, 2003 |
JP |
2003-424655 |
Claims
1. A polybenzazole fiber having a strength retention (%) of 80% or
more, which is determined by the equation: (a/b).times.100,
provided that the notations a and b are defined as follows: the
notation a indicates the strength of a yarn [cN/dtex] measured as
follows: polybenzazole filaments are S-wise twisted so that the
twist coefficient can be 30, to thereby make a yarn, which is then
left to stand alone for 30 seconds, and the yarn is S-wise
untwisted until the twist coefficient is decreased to 6, and the
untwisted yarn is exposed to an atmosphere of 80.degree. C. and 80
RH % for 240 hours and taken out at room temperature to measure the
strength of the yarn; and the notation b indicates the strength of
a yarn [cN/dtex] measured as follows: polybenzazole filaments are
S-wise twisted so that the twist coefficient can be 30, to thereby
make a yarn, which is then left to stand alone for 30 seconds, and
the yarn is S-wise untwisted until the twist coefficient is
decreased to 6, and the strength of the untwisted yarn is
measured.
2. A polybenzazole fiber according to claim 1, wherein the average
strength of a single polybenzazole fiber with an average diameter d
of 5 to 22 .mu.m and a length of 100 mm is 4.5 GPa or more.
3. A polybenzazole fiber according to claim 1, wherein the
coefficient of variation CV (a standard deviation/an average value)
of the diameters of a single filament, measured at 10 mm intervals
over 500 mm length of the filament is 0.08 or less.
4. A polybenzazole fiber according to claim 1, wherein the
stoichiometric ratio of an inorganic base to a mineral acid
remaining in the fiber is 0.8 to 1.4:1.
5. A polybenzazole fiber according to claim 1, which contains an
organic pigment having a thermal decomposition temperature of
200.degree. C. or higher and is soluble in a mineral acid.
6. A polybenzazole fiber according to claim 5, wherein the content
of the organic pigment is 2 to 8 mass %.
7. A spun yarn comprising a polybenzazole fiber according to claim
1, as at least one component.
8. A cord for reinforcing rubber, comprising a polybenzazole fiber
according to claim 1, as at least one component.
9. A composite material comprising a polybenzazole fiber according
to claim 1, as at least one component.
10. A woven or knitted fabric comprising a polybenzazole fiber
according to claim 1, as at least one component.
11. A knife-proof material comprising a polybenzazole fiber
according to claim 1, as at least one component.
12. A bullet-proof vest comprising a polybenzazole fiber according
to claim 1, as at least one component.
13. A high strength fiber rope comprising a polybenzazole fiber
according to claim 1, as at least one. component.
14. A sail cloth comprising a polybenzazole fiber according to
claim 1, as at least one component.
Description
FIELD OF THE INVENTION
[0001] The present application has been filed claiming the priority
based on the Japanese patent application Nos. 2003-412681,
2003-424648, 2003-424649, 2003-424650; 2003-424651, 2003-424652,
2003-424653, 2003-424654 and 2003-424655, and a whole of the
descriptions of these applications are herein fully incorporated in
the description of the present specification by reference.
[0002] The present invention relates to polybenzazole fibers which
can still have high durability against atmospheres of high
temperatures and high humidity even after yarns made thereof have
had kink bands therein due to the damages in the course of
post-processing for making woven fabrics, knitted fabrics, braids,
ropes and cords. The invention also relates to articles comprising
the polybenzazole fibers, particularly spun yarns,
rubber-reinforcing materials, fiber-reinforced composite materials,
woven or knitted fabrics, knife-proof materials or bullet-proof
vests, ropes and sail cloths.
BACKGROUND OF THE INVENTION
[0003] As high strength and high heat resistant fibers, there are
known polybenzazole fibers comprising a polybenzoxazole or a
polybenzothiazole, or a copolymer thereof.
[0004] In general, the filaments of polybenzazole are obtained by
extruding a dope containing the above polymer or copolymer and an
acid solvent through a spinneret, dipping the resulting semi-solid
filaments in a fluid for solidifying them (water, or a mixture of
water and an inorganic acid) to solidify them, thoroughly washing
the solid filaments in a water bath to remove most of the solvent
therefrom, allowing the filaments to pass through a bath holding an
aqueous solution of an inorganic base to thereby neutralize the
acid which has not been extracted and still remained in the
filaments, and drying the same.
[0005] Polybenzazole fibers have been variously applied, because
they are excellent in mechanical properties such as strength and
also have high heat resistance. Lately, the polybenzazole fibers
are expected to have further improved performance. Particularly
desired are such polybenzazole fibers that can still have high
durability against atmospheres of high temperatures and high
humidity even after yarns made thereof have had kink bands therein
due to the damages in the course of post-processing for making
articles comprising the same, such as woven fabrics, knitted
fabrics, braids, ropes and cords. In other words, such
polybenzazole fibers are earnestly desired that can sufficiently
maintain the strength thereof even after exposed to atmospheres of
high temperatures and high humidity over long periods of time.
[0006] For example, spun yarns made of the polybenzazole fibers are
known. However, such spun yarns are demanded to have further
improved performance. Particularly desired are such polybenzazole
fibers that can still have durability against atmospheres of high
temperatures and high humidity even after yarns made of the same
have had kink bands therein due to damages which occur in the
course of post-processing for making woven or knitted fabrics,
braids, ropes, cords, etc. of such yarns. In other words, such
polybenzazole fibers are strongly demanded that can sufficiently
maintain the strength thereof even after exposed to atmospheres of
high temperatures and high humidity over long periods of time.
[0007] Conventionally, nylon fibers, polyester fibers, glass fibers
and steel fibers have been mainly used as rubber-reinforcing
materials for tires, hoses, belts and the like. Recently, aromatic
polyamide fibers having high strength and high elastic modulus,
such as KEVLAR, have been used as reinforcing materials for a
variety of rubbers. Under these circumstances, the use of the
polybenzazole fibers as rubber-reinforcing materials have attracted
keen public attentions, because the polybenzazole fibers have far
higher strength and elastic modulus and higher heat resistance and
dimensional stability than the aromatic polyamide fibers. Under
such a situation, investigations have been made on the use of the
polybenzazole fibers as rubber-reinforcing fibers which are
required to have still higher strength and heat resistance that the
organic fibers conventionally used in the field of rubber materials
can not possess.
[0008] Under such circumstances, particularly desired are such
polybenzazole fibers for reinforcing rubber, that can sufficiently
maintain the strength thereof, when the internal solid of rubber
has high temperature and high humidity because of the dynamic
fatigue applied to the rubber-reinforcing material.
[0009] Glass fibers have hitherto been used in fiber-reinforced
composite materials. Recently, composite materials comprising
carbon fibers or aramid fibers have been developed in order to
improve the strength of the composite materials and reduce the
weight thereof, and such composite materials have been practically
used. Carbon fibers, however, have a problem in their poor impact
resistance and fragility, although having very excellent dynamical
performance. Aramid fibers have relatively high impact resistance,
but have a lower elastic modulus than the carbon fibers and thus
are poor in reinforcing effect. Under these circumstance,
fiber-reinforced composite materials comprising the polybenzazole
fibers are expected as the products of the next generation, since
they are excellent in both of impact resistance and elastic
modulus, exhibiting a superior reinforcing effect over the carbon
fibers.
[0010] However, the fiber-reinforced composite materials comprising
the polybenzazole fibers are demanded to have further improved
performance. Particularly desired is a fiber-reinforced composite
material which comprises such polybenzazole fibers that can
sufficiently maintain the strength thereof when exposed to an
atmosphere of high temperature and high humidity over a long period
of time.
[0011] As mentioned above, the polybenzazole fibers have high
mechanical properties such as strength and elastic modulus, and
therefore are used as fibrous materials for protective materials,
protective clothes and industrial materials. However, woven or
knitted fabrics comprising the polybenzazole fibers are demanded to
have further improved performance. Particularly desired is a woven
or knitted fabric comprising such polybenzazole fibers that can
sufficiently maintain the strength thereof when exposed to an
atmosphere of high temperature and high humidity over a long period
of time.
[0012] Conventionally, aramid fibers have been used to make
knife-proof materials or bullet-proof vests, and recently,
knife-proof materials or bullet-proof vests made of high strength
polyethylene fibers have been developed and put into practical use.
The knife-proof materials or bullet-proof vests made of the aramid
fibers require lots of the fibers to exhibit the desired protective
performance, and thus are thick and heavy in weight and are
uncomfortable to wear. Therefore, ones can not always wear them. On
the other hand, knife-proof materials or bullet-proof vests made of
high strength polyethylene fibers are reduced in weight but not in
thickness because of the small specific gravity of the fibers.
Under these circumstances, knife-proof materials or bullet-proof
vests made of the polybenzazole fibers can exhibit superior
protective performance over the knife-proof materials or
bullet-proof vests made of the aramid fibers and the high strength
polyethylene fibers, and are expected as thin and light weight
knife-proof materials or bullet-proof vests of the next
generation.
[0013] However, the knife-proof materials or bullet-proof vests
made of the polybenzazole fibers are demanded to have further
improved performance. Particularly desired is a knife-proof
materials or bullet-proof vest made of such polybenzazole fibers
that can sufficiently maintain the strength thereof when exposed to
an atmosphere of high temperature and high humidity over a long
period of time.
[0014] Since the polybenzazole fibers have high mechanical
properties such as strength and also have high heat resistance as
mentioned above, they have been widely used in ropes, including
yacht ropes, which are required to have strength and abrasion
resistance. However, the polybenzazole fibers are susceptible to
mechanical damages in the course of manufacturing of ropes, since
they have very highly oriented molecular chain structures. To
overcome this problem, there is a demand for such polybenzazole
fibers that can still have high durability against atmospheres of
high temperatures and high humidity even after yarns made thereof
have had kink bands therein due to the damages in the course of
post-processing for making ropes and cords, in other words, such
polybenzazole fibers that can sufficiently maintain the strength
thereof even when exposed to atmospheres of high temperatures and
high humidity over long periods of time.
[0015] Sail cloths comprising the polybenzazole fibers also have
been widely used. Particularly, yacht sails for use in yacht races
are demanded to have high tensile resistance and high tensile
strength so as not to permit their designed shapes to deform due to
winds. To solve this problem, such a sail cloth is dominantly used
that is made by sandwiching a woven fabric or a scrim which
comprises fibers having high strength and a high elastic modulus,
between two films of polyester or the like to form their
lamination, and molding the lamination into the sail cloth.
Further, a method of making a yacht sail as an integral
three-dimensional molded article has been developed. Such an
integral three-dimensional molded article is also included in the
scope of the sail cloth referred to in the description of the
present invention. Conventionally, para-aramid fibers or carbon
fibers have been used to make these products by employing the above
technique. Carbon fibers have a higher tensile elastic modulus than
para-aramid fibers, and thus are expected to improve the
performance of a yacht sail made thereof, but are easily bent and
thus are inferior in fatigue resistance. To overcome these
problems, yacht sails comprising the polybenzazole fibers have been
developed, and such yacht sails have proved their excellent
performance in the world-wide yacht races.
[0016] However, the yacht sails comprising the polybenzazole fibers
are demanded to have further improved performance. Especially
desired is a yacht sail made of such polybenzazole fibers that can
sufficiently maintain the strength thereof when exposed to an
atmosphere of high temperature and high humidity over a long period
of time.
DISCLOSURE OF THE INVENTION
Subject Matter to be Achieved by the Invention
[0017] The present invention has been developed under the foregoing
circumstances, and an object of the invention is to provide
polybenzazole fibers which show less decrease in strength, even
after yarns made thereof have had kink bands therein due to damages
thereof, and even after the fibers have been exposed to atmospheres
of high temperatures and high humidity over long periods of
time.
[0018] Another object of the present invention is to provide
articles comprising the polybenzazole fibers, such as spun yarns,
woven or knitted fabrics, rubber-reinforcing materials,
fiber-reinforced composite materials, ropes, sail cloths, and
knife-proof materials or bullet-proof vests.
Means for Achieving the Subject Matter
[0019] The present invention provides the followings.
[0020] 1. A polybenzazole fiber having a strength retention (%) of
80% or more, which is determined by the equation: (a/b).times.100,
provided that the notations a and b are defined as follows:
[0021] the notation a indicates the strength of a yarn [cN/dtex]
measured as follows: polybenzazole filaments are S-wise twisted so
that the twist coefficient can be 30, to thereby make a yarn, which
is then left to stand alone for 30 seconds, and the yarn is S-wise
untwisted until the twist coefficient is decreased to 6, and the
untwisted yarn is exposed to an atmosphere of 80.degree. C. and 80
RH % for 240 hours and taken out at room temperature to measure the
strength of the yarn; and
[0022] the notation b indicates the strength of a yarn [cN/dtex]
measured as follows: polybenzazole filaments are S-wise twisted so
that the twist coefficient can be 30, to thereby make a yarn, which
is then left to stand alone for 30 seconds, and the yarn is S-wise
untwisted until the twist coefficient is decreased to 6, and the
strength of the untwisted yarn is measured.
[0023] 2. A polybenzazole fiber according to the above paragraph 1,
wherein the average strength of a single polybenzazole fiber with
an average diameter D of 5 to 22 .mu.m and a length of 100 mm is
4.5 GPa or more.
[0024] 3. A polybenzazole fiber according to the above paragraph 1,
wherein the coefficient of variation CV (a standard deviation/an
average value) of the diameters of a single filament, measured at
10 mm intervals over 500 mm length of the filament is 0.08 or
less.
[0025] 4. A polybenzazole fiber according to the above paragraph 1,
wherein the stoichiometric ratio of an inorganic base to a mineral
acid remaining in the fiber is 0.8 to 1.4:1.
[0026] 5. A polybenzazole fiber according to the above paragraph 1,
which contain an organic pigment having a thermal decomposition
temperature of 200.degree. C. or higher and soluble in a mineral
acid.
[0027] 6. A polybenzazole fiber according to the above paragraph 5,
wherein the content of the organic pigment is 2 to 8 mass %.
[0028] 7. A spun yarn comprising a polybenzazole fiber according to
any of the above paragraphs 1 to 6, as at least one component.
[0029] 8. A cord for reinforcing rubber, comprising a polybenzazole
fiber according to any of the above paragraphs 1 to 6, as at least
one component.
[0030] 9. A composite material comprising a polybenzazole fiber
according to any of the above paragraphs 1 to 6, as at least one
component.
[0031] 10. A woven or knitted fabric comprising a polybenzazole
fiber according to any of the above paragraphs 1 to 6, as at least
one component.
[0032] 11. A knife-proof material comprising a polybenzazole fiber
according to any of the above paragraphs 1 to 6, as at least one
component.
[0033] 12. A bullet-proof vest comprising a polybenzazole fiber
according to any of the above paragraphs 1 to 6, as at least one
component.
[0034] 13. A high strength fiber rope comprising a polybenzazole
fiber according to any of the above paragraphs 1 to 6, as at least
one component.
[0035] 14. A sail cloth comprising a polybenzazole fiber according
to any of the above paragraphs 1 to 6, as at least one
component.
[0036] The present inventors have discovered the following facts
and accomplished the present invention.
[0037] (1) The durability of a yarn made of fibers containing a
specified amount of an organic pigment which has heat resistance as
high as a thermal decomposition temperature of 200.degree. C. or
higher and is soluble in a mineral acid, and which preferably has
group(s) of --N= and/or NH-- in the molecule and which is selected
from perinones and/or perylenes, phthalocyanines and quinacridones,
under an atmosphere of high temperature and high humidity, is
improved, and the strength of such a yarn very hardly decreases
even after the yarn has had kink bands therein due to the damages
thereof, more specifically, even after the yarn has been exposed to
an atmosphere of high temperature and high humidity over a long
period of time, as compared with a yarn made of fibers not
containing such an organic pigment.
[0038] (2) The durability of a yarn made of polybenzazole fibers,
under an atmosphere of high temperature and high humidity is
improved, even after the yarn has had a kink band therein due to
damages, by maintaining the pH of the internal of the yarn at and
around 7, which is a very important factor. Specifically, the
strength of such a yarn very hardly decreases even after the
exposure to an atmosphere of high temperature and high humidity
over a long period of time.
BRIEF DESCRIPTION OF THE DRAWING
[0039] FIG. 1 shows an example of a resin-impregnating apparatus
with a die for making a composite material comprising the
polybenzazole fibers of the present invention. In the drawing, A
refers to a filament; B, to an introduction angle; C, to the
diameter of a nozzle; D, to the length of the parallel portion; and
E, to a die.
BEST MODES FOR CARRYING OUT THE INVENTION
[0040] Hereinafter, the present invention will be described in more
detail.
[0041] The polybenzazole fibers according to the present invention
means fibers which comprise a polybenzazole polymer. The
polybenzazole polymer (hereinafter referred to as PBZ) is at least
one polymer selected from the group consisting of polybenzoxazole
(hereinafter referred to as PBO), polybenzothiazole (hereinafter
referred to as PBT) and polybenzimidazole (hereinafter referred to
as PBI).
[0042] In the present invention, PBO means a polymer which contains
an oxazole ring bonded to an aromatic group which is not
necessarily a benzene ring. Examples of PBO include lots of
polymers each of which comprises a unit of a plurality of oxazole
rings bonded to poly(p-phenylenebenzbisoxazole) or an aromatic
group. Analogous structures are also applied to PBT and PBI.
[0043] Examples of the polybenzazole polymer of the present
invention also include optional mixtures of PBO, PBT and PBI, and
block or random copolymers each of which comprises at least two of
PBO, PBT and PBI.
[0044] The structural unit in the PBZ polymer is preferably
selected from lyotropic liquid crystalline polymers which form
liquid crystals in mineral acids at specified concentrations. Such
a polymer comprises a monomer unit of any of the following
structural formulas (a) to (f): ##STR1##
[0045] The polybenzazole fibers can be manufactured from a dope
containing a PBZ polymer. As a suitable solvent for preparing this
dope, cresol or a non-oxidizing acid capable of dissolving the
polymer is used. Preferred examples of the non-oxidizing acid
include polyphosphoric acid, methanesulfonic acid, highly
concentrated sulfuric acid, and mixtures thereof. Above all,
polyphosphoric acid and methanesulfonic acid are preferred, and
polyphosphoric acid is especially preferred.
[0046] The concentration of the polymer in the dope is preferably
at least about 7 mass %, more preferably at least 10 mass %,
particularly at least 14 mass %. The maximum concentration of the
polymer is limited depending on the practical handling ease of the
dope, for example, the solubility of the polymer or the viscosity
of the dope. Because of such restrictive factors, the concentration
of the polymer is generally not higher than 20 mass %.
[0047] In the present invention, a suitable polymer or copolymer
and a suitable dope can be prepared by any of known methods, for
example, described in the publications of 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).
[0048] According to the above patent literature, a suitable monomer
is reacted in a non-oxidizing and dehydrating acid solution under a
non-oxidizing atmosphere, while being stirred at high speed under a
high shearing condition, at a temperature which is increased
stepwise or at a constant rate from about 60.degree. C. to about
230.degree. C., to thereby form a dope.
[0049] The dope thus obtained is extruded through a spinneret, and
the resulting semi-solid filaments are drawn long in an air to
thereby form solid filaments. The preferred methods therefor are
described in the above literature and the publication of U.S. Pat.
No. 5,034,250. In particular, the dope extruded through the
spinneret is allowed to pass through a space between the spinneret
and the washing bath. This space is called an air gap, and is
generally charged with a gas such as an air, nitrogen, argon,
helium, carbon dioxide or the like, or may be charged with a liquid
which does not dissolve the solvent or react with the dope.
[0050] The filaments resulting from the spinning are washed so as
not to be excessively drawn, and a part of the solvent is removed.
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
the filaments are allowed to contact a liquid which is compatible
with a mineral acid dissolving the polybenzazole polymer and which
does not serve as a solvent for the polybenzazole polymer, to
thereby remove the acid solvent from the dope. As a preferable
washing liquid, water or a mixture of water with an acid solvent is
used. Preferably, the filaments are washed until the concentration
of the residual mineral acid reached 8,000 ppm or less, preferably
5,000 ppm or less. After that, the filaments are dried and
heat-treated, and if needed, are wound up.
[0051] As the organic pigment which has heat resistance as high as
a thermal decomposition temperature of 200.degree. C. or higher and
which is dissolved in a mineral acid, there can be used any of
organic pigments that can be left to remain in the fibers or
filaments when added in the course of the polymerization or added
to a polymer dope and involved in the spinning from the such a
dope. Specific examples of such an organic pigment include
insoluble azo pigments, condensed azo pigments, color lakes,
isoindolinones, isoindolines, dioxazines, perinones and/or
perylenes, phthalocyanines, quinacridones and the like. Among
those, preferred are the organic pigments each having group(s) of
--N= and/or NH-- in the molecule, and more preferred are perinones
and/or perylenes, phthalocyanines and quinacridones.
[0052] Examples of perinones and/or perylenes include
bisbenzimidazo[2,1-b:2',1',i]benzo[1
mn][3,8]phenanthroline-8,17-dione,
bisbenzimidazo[2,1-b:1',2'-j]benzo[1
mn][3,8]phenanthroline-6,9-dione,
2,9-bis(p-methoxybenzyl)anthora[2,1,9-def:
6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetron,
2,9-bis(p-ethoxybenzyl)anthora[2,1,9-def:
6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetron,
2,9-bis(3,5-dimethoxybenzyl)anthora[2,1,9-def:
6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetron,
2,9-bis(p-methoxyphenyl)anthora[2,1,9-def:
6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetron,
2,9-bis(p-ethoxyphenyl)anthora[2,1,9-def:
6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetron,
2,9-bis(3,5-dimethylphenyl)anthora[2,1,9-def:
6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetron,
2,9-dimethylanthora[2,1,9-def:
6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetron,
2,9-bis(4-phenylazophenyl)anthora[2,1,9-def:
6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetron,
8,16-pyranthrenedione, etc. Each of these perinones may be used
alone or in combination.
[0053] As the phthalocyanines, any of phthalocyanines that have
phthalocyanine backbones may be used, independently of the presence
or absence of a metal at the center of the ligand and the kind of
an atom. Specific examples of these compounds are
29H,31H-phthalocyanate(2-)-N29,N30,N31,N32 copper,
29H,31H-phthalocyanate(2-)-N29,N30,N31,N32 iron,
29H,31H-phthalocyanate-N29,N30,N31,N32 cobalt,
29H,31H-phthalocyanate(2-)-N29,N30,N31,N32 copper,
oxo(29H,31H-phthalocyanate(2-)-N29,N30,N31,N32),(SP-5-12) titanium,
etc. The backbone of each of these phtalocyanines may have at least
one substituent such as a halogen atom, methyl group, methoxy group
or the like. Each of these phthalocyanines may be used alone or in
combination.
[0054] Examples of the quinacridones include
5,12-dihydro-2,9-dimethylquino[2,3-b]acridine-7,14-dione,
5,12-dihydroquino[2,3-b]acridine-7,14-dione,
5,12-dihydro-2,9-dichloroquino[2,3-b]acridine-7,14-dione,
5,12-dihydro-2,9-dibromoquino[2,3-b]acridine-7,14-dione, etc. Each
of these quinacridones may be used alone or in combination.
[0055] Further, each of the above perylenes, perinones,
phthalocyanines and quinacridones may be used in combination with
at least another one or more selected therefrom.
[0056] There is no particular limit in selection of the method for
containing the above organic compound in the filaments. The organic
compound may be added in any of the steps for the polymerization of
polybenzazole, or may be added to a polymer dope obtained after
completion of the polymerization. For example, the organic pigment
may be added together with the starting materials for
polybenzazole, or may be added in some stages or at an optional
point of time during the reaction which proceeds while the reaction
temperature is being raised at an optional rate. Otherwise, the
organic pigment may be added to the reaction system after
completion of the polymerization, and stirred and mixed into the
reaction system.
[0057] The most distinguishing feature of the polybenzazole fibers
of the present invention is that a yarn made of the polybenzazole
fibers by twisting at a twist coefficient of 30 can have a strength
retention of 80% or more after exposed to an atmosphere of
80.degree. C. and 80 RH % for 240 hours. The polybenzazole fibers
of the present invention shows a strength retention of 80% or more,
defined by the equation of (a/b).times.100.
[0058] In the above equation, the notation a means strength
[cN/dtex] measured as follows. The filaments are S-wise twisted
until the twist coefficient can be 30, to thereby make a S-twisted
yarn, which is then left to stand alone for 30 seconds. The yarn is
then S-wise untwisted until the twist coefficient is decreased to
6. The untwisted yarn is exposed to an atmosphere of 80.degree. C.
and 80 RH % for 240 hours, and is taken out to an atmosphere of a
room temperature to measure the strength thereof.
[0059] The notation b means strength [cN/dex] measured as follows.
The filaments are S-wise twisted until the twist coefficient can be
30, to thereby make a S-twisted yarn, which is then left to stand
alone for 30 seconds. The yarn is then S-wise untwisted until the
twist coefficient is decreased to 6. Then, the strength of the
untwisted yarn is measured.
[0060] The strength retention (%) of the polybenzazole fibers of
the present invention is preferably 80 to 100%, more preferably 82
to 100%, still more preferably 84 to 100%, far more preferably 85
to 100%, specifically 80 to 99%, and more specifically 80 to 98%,
still more specifically 84 to 98%.
[0061] Since the molecules of the polybenzazole fibers have high
rigidity and the interaction between each of the molecular chains
is low, kink bands occur in directions vertically to the axial
directions of the polybenzazole fibers when a bending stress is
applied to the polybenzazole fibers. While the degrees of the kink
bands differ depending on the kinds of post processing, kink bands
usually occur in fibers which have undergone post processing. Kink
bands also occur in fibers which are simply twisted, if the number
of twists is increased. The polybenzazole fibers having had kink
bands therein show larger decrease in the strength thereof when
exposed to an atmosphere of high temperature and high humidity over
a long period of time, as compared with polybenzazole fibers having
no kink band therein. However, this disadvantage can be solved by
containing any of the above organic pigments in the filaments after
spinning. That is, the polybenzazole filaments containing the
organic pigment, even though having kink bands therein, show higher
durability against an atmosphere of high temperature and high
humidity, namely, shows a less decrease in the strength thereof
when exposed to such an atmosphere over a long period of time.
Thus, the yarns of the polybenzazole fibers which are damaged to
have kink bands therein in the course of the post processing for
making woven fabrics, knitted fabrics, brads, ropes, cords or the
like, show high durability against atmospheres of high temperatures
and high humidity. The organic pigment herein referred to means
such an organic pigment that has heat resistance as high as a
thermal decomposition temperature of 200.degree. C. or higher and
is soluble in a mineral acid, and preferably has group(s) of --N=
and/or NH-- in the molecule. More preferably, such an organic
pigment is selected from perinones and/or perylenes,
phthalocyanines and quinacridones.
[0062] Desirably, the polybenzazole fibers of the present invention
have a stoichiometric ratio of an inorganic base to a mineral acid,
remaining in the fibers, of 0.8 to 1.4:1. When the stoichiometic
ratio of the inorganic base to the mineral acid in the fibers is
too small, the pH inside of the fibers extremely inclines to the
acidic side, which accelerates the hydrolysis of the PBZ molecules
and lowers the strength of the fibers. This tendency becomes more
remarkable in the polybenzazole fibers having kink bands therein,
as compared with polybenzazole fibers having no kink band therein.
Thus, the polybenzazole fibers having kink bands therein show
larger decrease in strength when exposed to an atmosphere of high
temperature and high humidity over a long period of time. On the
other hand, when the stoichiometic ratio of the inorganic base to
the mineral acid in the fibers is too large, the pH inside of the
fibers extremely inclines to the basic side, which accelerates the
hydrolysis of the PBZ molecules and lowers the strength of the
fibers. This tendency becomes more remarkable in the polybenzazole
fibers having kink bands therein, as compared with polybenzazole
fibers having no kink band therein. Thus, the polybenzazole fibers
having kink bands therein show larger decrease in strength when
exposed to an atmosphere of high temperature and high humidity over
a long period of time. For this reason, the stoichiometric ratio of
the inorganic base to the mineral acid, remaining in the fibers, is
preferably 0.8 to 1.4:1, more preferably 1.0 to 1.3:1. Desirably,
this stoichiometic ratio can be found in any portions of the
fibers. As the method of neutralizing the fibers with the inorganic
base in the washing step, a guide oiling system, showering system,
dipping system or the like is employed. The method, however, is not
limited to these.
[0063] The content of the above organic pigment in the
polybenzazole fibers of the present invention is preferably 2 to 8
mass %, more preferably 3 to 6 mass %. When this content is too
low, the effect of the organic pigment in the fibers becomes poor:
namely, the effect of improving the durability of the fibers having
had kink bands therein, specifically, the effect of suppressing the
lowering of the strength of the fibers when such fibers have been
exposed to an atmosphere of high temperature and high humidity over
a long period of time, becomes poor. On the other hand, when this
content is too large, the fineness of the polybenzazole filaments
becomes larger, and such filaments have uneven thickness, which
lowers the initial strength of the filaments. When this content is
in the range of 2 to 8 mass %, the initial strength of the
filaments does not decrease due to the presence of the organic
pigment in the filaments, and the spinnable property of the dope is
sufficient. Thus, smooth spinning can be maintained without any
filament breakage. This may be because the pigment added is
dissolved in the mineral acid and thus also still dissolved in the
polymer dope. However, this speculation does not restrict the
present invention in any way.
[0064] The polybenzazole fibers of the present invention has an
average diameter D of 5 to 22 .mu.m, more preferably 10 to 20
.mu.m, as a single filament.
[0065] The average strength of the polybenzazole fibers is
preferably 4.5 GPa or more, more preferably 5.0 to 8.0 GPa,
provided that the length of the fiber is 100 mm.
[0066] The polybenzazole fibers of the present invention preferably
contain the organic pigment therein, as mentioned above. Therefore,
sufficient control is needed to prevent the unevenness in the
diameters of the fibers. The coefficient of variation CV (a
standard deviation/an average value) of the diameters of a single
polybenzazole filament of the present invention, measured at 10 mm
intervals over a length of 500 mm, is preferably 0.08 or less, more
preferably 0.06 or less. When the coefficient of variation CV is
too large, a stress tends to concentrate on the thin portion of the
fiber, so that the fiber is easily broken.
[0067] The polybenzazole fibers of the present invention show high
durability against an atmosphere of high temperature and high
humidity, and thus are variously and suitably used in the following
articles. Particularly, the polybenzazole fibers of the present
invention are suitably used in spun yarns, rubber-reinforcing
materials, fiber-reinforced composite materials, woven or knitted
fabrics, knife-proof materials or bullet-proof vests, ropes, sail
cloths and the like.
[0068] The polybenzazole fibers of the present invention are
suitably used in spun yarns, especially, spun yarns for use in
fibrous structures of industrial materials for protective materials
or protective clothing such as fireman uniforms, fire-resistant
clothing and working wears, conveyer materials, cushion materials,
coating protective materials, etc., which are all required to have
high strength and high heat resistance.
[0069] The spun yarns of the present invention include composite
spun yarns blended with other kinds of fibers. As other kinds of
fibers, natural fibers, organic fibers, metal fibers, inorganic
fibers, mineral fibers and the like may be used. The method of
blending fibers and the forms of yarns are not limited, and the
generic method using opener and scutcher may be employed, or the
composite yarn may be in the form of a yarn having a core-in-sheath
structure.
[0070] The polybenzazole fibers of the present invention can be
suitably used as rubber-reinforcing materials for tires, belts and
hoses.
[0071] The polybenzazole fibers for use in rubber-reinforcing cords
may be made into a single twist yarn or a two folded twist yarn
with a ring twisting machine or the like, in order to improve the
fatigue resistance. In this case, the twist coefficient (K) may be
10 to 100.
[0072] To improve the adhesivity of the polybenzazole fibers with
rubber, the polybenzazole fibers may be surface-treated with corona
or plasma. Further, a compound reactive with the surfaces of the
polybenzazole fibers or the corona-treated surfaces of the
polybenzazole fibers may be added to the polybenzazole fibers. To
otherwise improve the adhesivity with rubber, the polybenzazole
fibers may be subjected to a dipping treatment.
[0073] As the treating liquid, each of the following liquids may be
generally used alone or in combination so as to treat the fibers in
one stage or two or more stages, although any other method may be
applicable: (A) an aqueous dispersion of an epoxy resin, (B) an
aqueous dispersion of a blocked isocyanate, (C) an aqueous
dispersion of a rubber latex, and (D) a liquid mixture of a
resorcin/formaldehyde resin and a rubber latex (RFL).
[0074] The polybenzazole fibers of the present invention can be
suitably used in composite material. The composite material
comprising the polybenzazole fibers of the present invention may be
in any form of an unidirectionally reinforced material, a
pseudoisotropic laminated layer and a fabric laminated layer. As a
matrix resin, there may be used any of thermosetting resins such as
an epoxy resin and a phenol resin, super engineering plastics such
as PPS and PEEK, and general-purpose thermoplastic resins such as
PE, PP and polyamide.
[0075] The polybenzazole fibers of the present invention can be
suitably used in woven or knitted fabrics, particularly for
protective materials for fireman uniforms, fire resistant clothing
and working wears, and protective clothing which are required to
have high strength and high heat resistance, and woven or knitted
fabrics for industrial materials for use in conveyer materials,
cushion materials and coating protective materials which are
required to have high strength and high heat resistance.
[0076] The woven or knitted fabrics of the present invention
include composite woven or knitted fabrics in combination with
other kinds of fibers. As other kinds of fibers, natural fiber,
organic fibers, metal fibers, inorganic fibers, mineral fibers and
the like may be used. The combining method is not particularly
limited. The kinds of the woven fabrics include union cloth, double
woven cloth, lip stop, etc. The kinds of the knitted fabrics
include union knitting, double knitting, tubular knitting, weft
knitting, warp knitting, Raschel knitting, etc. The fiber bundles
composing the woven or knitted fabric are not particularly limited,
and examples thereof include monofilaments, multifilaments, twisted
yarns, twisted union yarns, covering yarns, spun yarns, stretch
broken yarns, yarns having a core-in-sheath structure, braids,
etc.
[0077] The polybenzazole fibers of the present invention can be
suitably used in knife-proof materials for vests and gloves. The
knife-proof material according to the present invention comprises a
lamination of woven fabrics made of the polybenzazole fibers. As
the texture of the woven fabric, any of a plain weave fabric, a
twill fabric and other textures generally used in fabrics may be
employed. Preferably, a plain weave fabric or a twill fabric in
which yarns are hard to move is selected to attain higher
knife-proof performance.
[0078] When the fineness of the polybenzazole fibers for use in the
knife-proof material according to the present invention is as low
as 600 dtex or less, preferably 300 dtex or less, higher
knife-proof performance can be attained. The density of yarns in a
woven fabric for use in a knife-proof material of the present
invention is preferably 30/25 mm or more, more preferably 50/25 mm
or more. When this density is low, the yarns tend to move, so that
sufficient knife-proof performance sometimes can not be obtained.
The weight of the fabric is preferably 100 g/m.sup.2 or more, more
preferably 150 g/m.sup.2 or more, in order to achieve higher
knife-proof performance. A part or a whole of the fabric of the
present invention may be coated with or impregnated with a resin.
The knife-proof material of the present invention is a lamination
of such fabrics. Otherwise, such fabrics may be sewn integrally
with a highly strong machine sewing thread for use as the
knife-proof material.
[0079] The polybenzazole fibers of the present invention can be
suitably used in a bullet-proof vest. The bullet-proof vest
according to the present invention is made of a lamination of
fabrics comprising the polybenzazole fibers. The texture of the
woven fabric may be any of a plain weave fabric, a twill fabric and
other textures generally employed in fabrics. Preferably, a plain
weave fabric or a twill fabric in which yarns are hard to move is
employed to attain higher bullet-proof performance.
[0080] When the fineness of the polybenzazole fibers for use in the
bullet-proof vest according to the present invention is as low as
1,110 dtex or less, preferably 600 dtex or less, higher
bullet-proof performance can be attained. The density of yarns in a
woven fabric for use in a bullet-proof vest of the present
invention is preferably 40/25 mm or less. The weight of the fabric
is preferably 200 g/m.sup.2 or less, more preferably 150 g/m.sup.2,
in order to achieve higher bullet-proof performance. The
bullet-proof vest of the present invention is made of a lamination
of such fabrics. Otherwise, such fabrics may be sewn integrally
with a highly strong machine sewing thread for use as the
bullet-proof vest.
[0081] The polybenzazole fibers of the present invention can be
suitably used in sail cloths. A sail cloth according to the present
invention can be made of the polybenzazole fibers in combination
with other high strength fibers such as polyethylene fibers,
para-aramide fibers, wholly aromatic polyester fibers or carbon
fibers. A sail cloth is reinforced in complicated directions. In
the present invention, it is important to improve the durability of
the polybenzazole fibers in the fiber axial direction, namely, the
strength retention thereof when the polybenzazole fibers are
exposed to an atmosphere of high temperature and high humidity over
a long period of time.
EXAMPLES
[0082] Hereinafter, the present invention will be described in more
detail by way of Examples thereof. However, the following Examples
should not be construed as limiting the scope of the present
invention in any way, and may be appropriately modified unless they
may be beyond the spirit of the present invention. Such
modifications are also included in the scope of the present
invention.
Method of Twisting Filaments
[0083] In accordance with the procedure of JIS-L1013, filaments
were set on a twist tester, and were twisted under a given load
determined by the following equation, so that the twist coefficient
of the twisted yarn could be 30 at an interval of 50 cm between
grips. The filaments were S-wise twisted and were left to stand
alone for 30 seconds. Then, the twisted filaments were S-wise
untwisted until the twist coefficient was decreased to 6. Thus, the
sample S-twisted filaments having a twist coefficient of 6 was
obtained. The equation for determining the given load (a) applied
to the filaments being twisted, and the equation showing a
relationship between the twist coefficient (K) and the number of
twists (Tw) are shown below. a=(1/10)D
K=0.124.times.Tw.times.D.sup.1/2
[0084] a: a given load (g)
[0085] Tw: number of twists (twisting times/inch)
[0086] D: the fineness of a filament (Dtex)
Evaluation of Durability under Atmosphere of High Temperature and
High Humidity
[0087] The durability of a filament against an atmosphere of high
temperature and high humidity was evaluated based on the retention
of the tensile strength of the filament found after a storage test
under an atmosphere of high temperature and high humidity, relative
to the tensile strength thereof found before the same test.
[0088] The sample filaments, twisted by the foregoing method
(S-twisted yarn having a twist coefficient of 6), were wound onto a
resinous bobbin with a diameter of 10 cm, and then were stored in
an air-conditioned container under an atmosphere of high
temperature and high humidity, and then were removed from the
container.
[0089] Untreated filaments were subjected to a tensile test at a
room temperature to measure the tensile strength thereof, which was
expressed as a (cN/dtex). The sample twisted by the foregoing
method (the S-twisted yarn having a twist coefficient of 6) was
subjected to a tensile test at a room temperature to measure the
tensile strength thereof, which was expressed as b (cN/dtex). The
strength retention was determined by dividing the value a by the
value b and multiplying the resultant quotient by 100. In this
regard, Humidic Chamber 1G43M manufactured by Yamato Kagakusha was
used in the above storage test. The sample was stored at a
temperature of 80.degree. C and a relative humidity of 80% for 240
hours in the air-conditioned container which was perfectly shielded
from light. The tensile strength was measured with a tensile tester
(AG-50KNG manufactured by SHIMADZU CORPORATION) according to the
procedure of JIS-L1013.
Evaluation of Concentrations of Phosphorus and Sodium Remaining in
Filament
[0090] The concentration of the residual phosphorus in the filament
was determined by a calorimetric analysis according to the
molybdenum blue method, after the sample had been subjected to a
wet decomposition. The concentration of the residual sodium in the
filament was determined as follows: the sample was carbonized and
incinerated, and the resulting ash was dissolved in an acid to form
a 1.2 N-HCl solution, from which the concentration of the residual
sodium was determined by the atomic absorption method.
[0091] Measurement of Diameter of Filament The diameter of a
filament may be measured by an optical means or by a mechanical
means such as a micrometer. In view of simplicity for measurement,
the use of an optical means such as a scanning electron microscope
(SEM), a laser type outer diameter measuring apparatus or the like
is preferable. To reflect a whole of image of the population of
filaments, it is needed to measure the diameters of as many single
filaments as possible: the diameters of at least 5%, preferably 7%
of the number of all filaments are measured. In many cases, the
variation in the thickness of a polybenzazole filament in the
lengthwise direction is larger than the variation in the thickness
of polybenzazole filaments relative to each of the polybenzazole
filaments. Accordingly, it is needed to measure the thickness of a
filament in the lengthwise direction at a sufficient number of
portions thereof. For this reason, the thickness of a filament with
a length of at least 500 mm or more, preferably at least 750 mm or
more in the lengthwise direction is measured at 25 mm or less
intervals at most, preferably 12 mm or less intervals. When this
interval is relatively long, there is a danger of missing the
measurement of the diameter of a narrow and neck-in portion of the
filament. In the investigation of the practical variation patterns,
the variation in the diameter of a filament is very small when the
measuring interval is less than 5 mm. In this point of view, the
method of measuring the diameter of a single filament at 10 mm
intervals over the 500 mm length of the filament is employed in the
present invention. The diameter of a single filament is measured at
its several portion, using a scanning electron microscope (SEM) of
a magnification of 5,000, and a standard deviation for assuming the
average value and the normal distribution of the measured diameters
is calculated, and a coefficient of variation (CV) is calculated by
the following equation, using the standard deviation. The
magnification of the scanning electron microscope is corrected by
using latex beads with known diameters, before the measurement is
conducted. [0092] CV=a standard deviation [.mu.m] of the diameter
of a single filament/an average diameter [.mu.m] of the single
filament Evaluation of Durability of Sail Cloth under Atmosphere of
High Temperature and High Humidity
[0093] The durability of a sail cloth under an atmosphere of high
temperature and high humidity was evaluated as follows. A sample of
a sail cloth was stored in a container conditioned constantly at a
high temperature and a high humidity. After that, the sample was
taken out to a laboratory in a standard state (the temperature:
20.+-.2.degree. C., and the relative humidity: 65.+-.2%), and was
then subjected to a tensile test within 30 minutes thereafter, so
that the retention of the tensile strength of the sample after the
exposure to the atmosphere of high temperature and high humidity,
relative to the tensile strength thereof before the same exposure
was evaluated. Humidic Chamber 1G43M manufactured by Yamato
Kagakusha was used for the storage test under the atmosphere of
high temperature and high humidity. The storage test was continued
for 240 hours in the above air-conditioned container which was
perfectly shielded from light and kept constant at 80.degree. C.
and 80% RH. The tensile strength of the sample with a width of 2.5
cm was measured with a tensile tester (AG-50KNG manufactured by
SHIMADZU CORPORATION) according to the procedure of JIS-L1096.
Evaluation of Durability of Rubber-Reinforcing Cord or Composite
Material under Atmosphere of High Temperature and High Humidity
[0094] The durability of a sample of a rubber-reinforcing cord or a
composite material under an atmosphere of high temperature and high
humidity was evaluated as follows. The sample was stored in a
container conditioned constantly at a high temperature and a high
humidity. After that, the sample was taken out to a laboratory in a
standard state (the temperature: 20.+-.2.degree. C., and the
relative humidity: 65.+-.2%), and was then subjected to a tensile
test within 30 minutes thereafter, so that the retention of the
tensile strength of the sample after the exposure to the atmosphere
of high temperature and high humidity, relative to the tensile
strength thereof before the same exposure was evaluated. Humidic
Chamber 1G43M manufactured by Yamato Kagakusha was used for the
storage test under the atmosphere of high temperature and high
humidity. The storage test was continued for 240 hours in the above
air-conditioned container which was perfectly shielded from light
and kept constant at 80.degree. C. and 80% RH. The tensile strength
of the sample was measured with a tensile tester (AG-50KNG
manufactured by SHIMADZU CORPORATION) according to the procedure of
JIS-L1013.
Evaluation of Durability of High Strength Fiber Rope under
Atmosphere of High Temperature and High Humidity
[0095] The durability of a high strength fiber rope which was not
subjected to the foregoing twisting process was evaluated. The
evaluation of the durability of the same under an atmosphere of
high temperature and high humidity was made as follows. The rope
was stored in a container conditioned constantly at a high
temperature and a high humidity. After that, the rope was taken out
to a laboratory in a standard state (the temperature:
20.+-.2.degree. C., and the relative humidity: 65.+-.2%), and was
then subjected to a tensile test within 30 minutes thereafter, so
that the retention of the tensile strength of the rope after the
exposure to the atmosphere of high temperature and high humidity,
relative to the tensile strength thereof before the same exposure
was evaluated. Humidic Chamber 1G43M manufactured by Yamato
Kagakusha was used for the storage test under the atmosphere of
high temperature and high humidity. The storage test was continued
for 240 hours in the above air-conditioned container which was
perfectly shielded from light and kept constant at 80.degree. C.
and 80% RH. The strength retention of the rope was determined by
measuring the tensile strengths of the rope found before and after
the storage test, dividing the tensile strength after the storage
test by the tensile strength before the same, and multiplying the
quotient by 100.
Evaluation of Durability of Woven or Knitted Fabric under
Atmosphere of High Temperature and High Humidity
[0096] The durability of a sample of a woven or knitted fabric
under an atmosphere of high temperature and high humidity was
evaluated as follows. The sample was stored in a container
conditioned constantly at a high temperature and a high humidity.
After that, the sample was taken out to a laboratory in a standard
state (the temperature: 20.+-.2.degree. C., and the relative
humidity: 65.+-.2%), and was then subjected to a tensile test
within 30 minutes thereafter, so that the retention of the tensile
strength of the sample after the exposure to the atmosphere of high
temperature and high humidity, relative to the tensile strength
thereof before the same exposure was evaluated. Humidic Chamber
1G43M manufactured by Yamato Kagakusha was used for the storage
test under the atmosphere of high temperature and high humidity.
The storage test was continued for 240 hours in the above
air-conditioned container which was perfectly shielded from light
and kept constant at 80.degree. C. and 80% RH. The tensile strength
of the woven fabric was measured according to the procedure of
JIS-L1096, with a tensile tester (AG-50KNG manufactured by SHIMADZU
CORPORATION), and the tensile strength of the knitted fabric was
measured according to the procedure of JIS-L1018, with the same
tensile tester.
Making of Sample of Composite Material
[0097] Filaments were unwound horizontally so as not to be twisted,
and allowed to contact the surfaces of five stainless steel
cylinders of .phi. 100 mm, alternately, so as to be opened. The
opened filaments were allowed to contact a curved die which was
shaped in a quarter of a circle with a semidiameter of 50 mm. A
resin was discharged from a slit formed on the inlet of the curved
die, in the forwarding direction of the running filaments, to
thereby coat the filaments with the resin. The filaments under a
tension were run over the curved surface of the die, to have a
shearing resistance so as to be impregnated with the resin. After
that, the filaments impregnated with the resin were allowed to pass
through a die having an inlet and a nozzle, and cooled to obtain a
rod-like composite material. FIG. 1 shows an example of this
resin-impregnating system with the die. As the resin, an
ethylene-vinyl alcohol copolymer "EVAL (R)" (105B) manufactured by
KURARAY CO., LTD. was used. The die used had an inlet angle of
30.degree., a nozzle with a diameter of 0.6 mm .phi., and a
parallel portion with a length of 0.5 mm.
Evaluation of Durability of Spun Yarn under Atmosphere of High
Temperature and High Humidity
[0098] The durability of a spun yarn which was not subjected to a
twisting process was evaluated. The spun yarn wound onto a resinous
bobbin was stored in a container conditioned constantly at a high
temperature and a high humidity. After that, the sample was taken
out and then subjected to a tensile test at a room temperature. The
resultant tensile strength was divided by a tensile strength of a
spun yarn which was not subjected to the above storage test, and
the resultant quotient was multiplied by 100 to obtain a strength
retention. Humidic Chamber 1G43M manufactured by Yamato Kagakusha
was used for the storage test under the atmosphere of high
temperature and high humidity, as well as in the evaluation of the
filaments before cutting. The storage test was continued for 240
hours in the above air-conditioned container which was perfectly
shielded from light and kept constant at 80.degree. C. and 80% RH.
The tensile strength of the spun yarn with a length of 200 mm was
measured according to the procedure of JIS-L1095, with a tensile
tester (AG-50KNG manufactured by SHIMADZU CORPORATION).
EXAMPLE 1
[0099] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g), terephthalic acid (260.8 g) and 122%
polyphosphoric acid (2,078.2 g) were stirred at 60.degree. C. for
one hour, and the mixture was gradually heated so as to be reacted
at 135.degree. C. for 25 hours, at 150.degree. C. for 5 hours and
at 170.degree. C. for 20 hours. Threne (14.8 g) was added to the
resultant poly(p-phenylenebenzobisoxazole) dope (2.0 kg) having an
intrinsic viscosity of 29 dL/g at 30.degree. C., measured using a
methanesulfonic acid solution, and the mixture was stirred.
[0100] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0101] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
polybenzazole filaments were measured by the foregoing methods. As
a result, the concentration of phosphorous was 4,600 ppm, and that
of sodium was 3,600 ppm; and the molar ratio of Na/P was 1.05.
[0102] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 86%.
[0103] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 87%.
[0104] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 89%.
[0105] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
87%.
[0106] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0107] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,220 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
86%.
[0108] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,660 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 85%.
[0109] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 135 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,850 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 84%.
[0110] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.29 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 82%.
[0111] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 15.3 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 84%.
[0112] Further, 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 resultant fabric was 135 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,600 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 83%.
EXAMPLE 2
[0113] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g), terephthalic acid (260.8 g) and 122%
polyphosphoric acid (2,078.2 g) were stirred at 60.degree. C. for
one hour, and the mixture was gradually heated so as to be reacted
at 135.degree. C. for 25 hours, at 150.degree. C. for 5 hours and
at 170.degree. C. for 20 hours. Copper phthalocyanine (14.8 g) was
added to the resultant poly(p-phenylenebenzobisoxazole) dope (2.0
kg) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, and the mixture was
stirred.
[0114] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0115] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 120
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,500 ppm, and that of sodium was
2,400 ppm; and the molar ratio of Na/P was 0.72.
[0116] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 83%.
[0117] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 82%.
[0118] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 85%.
[0119] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
85%.
[0120] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0121] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,250 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
82%.
[0122] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,660 N/S cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 80%.
[0123] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 134 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,890 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 82%.
[0124] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.30 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 80%.
[0125] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 14.8 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 81%.
[0126] Further, 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 resultant fabric was 136 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,580 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 80%.
EXAMPLE 3
[0127] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g), terephthalic acid (260.8 g) and 122%
polyphosphoric acid (2,078.2 g) were stirred at 60.degree. C. for
one hour, and the mixture was gradually heated so as to be reacted
at 135.degree. C. for 25 hours, at 150.degree. C. for 5 hours and
at 170.degree. C. for 20 hours. Copper phthalocyanine (14.8 g) was
added to the resultant poly(p-phenylenebenzobisoxazole) dope (2.0
kg) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, and the mixture was
stirred.
[0128] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0129] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,400 ppm, and that of sodium was
3,600 ppm; and the molar ratio of Na/P was 1.10.
[0130] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 88%.
[0131] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 90%.
[0132] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 91%.
[0133] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
90%.
[0134] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0135] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,250 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
87%.
[0136] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,670 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 85%.
[0137] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 136 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,800 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 86%.
[0138] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.30 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 87%.
[0139] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 15.8 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 85%.
[0140] Further, 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 resultant fabric was 135 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,620 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 85%.
EXAMPLE 4
[0141] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g), terephthalic acid (260.8 g) and 122%
polyphosphoric acid (2,078.2 g) were stirred at 60.degree. C. for
one hour, and the mixture was gradually heated so as to be reacted
at 135.degree. C. for 25 hours, at 150.degree. C. for 5 hours and
at 170.degree. C. for 20 hours. Copper phthalocyanine (14.8 g) was
added to the resultant poly(p-phenylenebenzobisoxazole) dope (2.0
kg) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, and the mixture was
stirred.
[0142] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0143] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 3
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,700 ppm, and that of sodium was
5,400 ppm; and the molar ratio of Na/P was 1.55.
[0144] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 86%.
[0145] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 86%.
[0146] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 87%.
[0147] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
88%.
[0148] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0149] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,190 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
84%.
[0150] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,660 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 83%.
[0151] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 135 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,700 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 83%.
[0152] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.30 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 83%.
[0153] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 15.1 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 84%.
[0154] Further, 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 resultant fabric was 136 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,550 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 82%.
EXAMPLE 5
[0155] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g), terephthalic acid (260.8 g) and 122%
polyphosphoric acid (2,078.2 g) were stirred at 60.degree. C. for
one hour, and the mixture was gradually heated so as to be reacted
at 135.degree. C. for 25 hours, at 150.degree. C. for 5 hours and
at 170.degree. C. for 20 hours. Copper phthalocyanine (4.4 g) was
added to the resultant poly(p-phenylenebenzobisoxazole) dope (2.0
kg) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, and the mixture was
stirred.
[0156] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0157] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,500 ppm, and that of sodium was
4,000 ppm; and the molar ratio of Na/P was 1.20.
[0158] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 81%.
[0159] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 82%.
[0160] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 83%.
[0161] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
81%.
[0162] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0163] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,300 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
83%.
[0164] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,740 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 83%.
[0165] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 133 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,920 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 80%.
[0166] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.29 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 79%.
[0167] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 14.5 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 80%.
[0168] Further, 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 resultant fabric was 133 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,690 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 79%.
EXAMPLE 6
[0169] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g), terephthalic acid (260.8 g) and 122%
polyphosphoric acid (2,078.2 g) were stirred at 60.degree. C. for
one hour, and the mixture was gradually heated so as to be reacted
at 135.degree. C. for 25 hours, at 150.degree. C. for 5 hours and
at 170.degree. C. for 20 hours. Copper phthalocyanine (32.5 g) was
added to the resultant poly(p-phenylenebenzobisoxazole) dope (2.0
kg) having an intrinsic viscosity of 30 dL/g at 30.degree. C.,
measured using a methanesulfonic acid solution, and the mixture was
stirred.
[0170] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0171] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,400 ppm, and that of sodium was
3,400 ppm; and the molar ratio of Na/P was 1.04.
[0172] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 87%.
[0173] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 89%.
[0174] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 85%.
[0175] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
88%.
[0176] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0177] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,010 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
87%.
[0178] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,590 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 85%.
[0179] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 138 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,610 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 86%.
[0180] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.31 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 85%.
[0181] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 15.5 cN/dtex. The
durability of the spun yarn under an-atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 85%.
[0182] Further, 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 resultant fabric was 138 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,280 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 84%.
EXAMPLE 7
[0183] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g) and terephthalic acid (252.7 g) were
added in 122% polyphosphoric acid (2,165.5 g) with stirring at
60.degree. C. for one hour, and the mixture was gradually heated so
as to be reacted at 120.degree. C. for 4 hours, at 135.degree. C.
for 20 hours and at 150.degree. C. for 5 hours. Further, to the
resultant oligomer dope, a dispersion obtained by adding
terephthalic acid (5.6 g) and copper phthalocyanine (19.5 g) in
122% polyphosphoric acid (74.4 g) was added, and the mixture was
allowed to react at 170.degree. C. for 5 hours and at 200.degree.
C. for 10 hours to obtain poly(p-phenylenebenzobisoxazole) dope
having an intrinsic viscosity of 29 dL/g at 30.degree. C., measured
using a methanesulfonic acid solution.
[0184] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0185] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 120
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,600 ppm, and that of sodium was
2,400 ppm; and the molar ratio of Na/P was 0.70.
[0186] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 84%.
[0187] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 81%.
[0188] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 86%.
[0189] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
86%.
[0190] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0191] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,240 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
83%.
[0192] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,690 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 82%.
[0193] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 136 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,820 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 82%.
[0194] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.29 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 81%.
[0195] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 15.0 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 83%.
[0196] Further, 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 resultant fabric was 135 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,500 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 80%.
EXAMPLE 8
[0197] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g) and terephthalic acid (252.7 g) were
added in 122% polyphosphoric acid (2,165.5 g) with stirring at
60.degree. C. for one hour, and the mixture was gradually heated so
as to be reacted at 120.degree. C. for 4 hours, at 135.degree. C.
for 20 hours and at 150.degree. C. for 5 hours. Further, to the
resultant oligomer dope, a dispersion obtained by adding
terephthalic acid (5.6 g) and copper phthalocyanine (19.5 g) in
122% polyphosphoric acid (74.4 g) was added, and the mixture was
allowed to react at 170.degree. C. for 5 hours and at 200.degree.
C. for 10 hours to obtain poly(p-phenylenebenzobisoxazole) dope
having an intrinsic viscosity of 29 dL/g at 30.degree. C., measured
using a methanesulfonic acid solution.
[0198] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0199] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,900 ppm, and that of sodium was
4,200 ppm; and the molar ratio of Na/P was 1.15.
[0200] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 89%.
[0201] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 88%.
[0202] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 91%.
[0203] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
92%.
[0204] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0205] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,210 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
88%.
[0206] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,660 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 85%.
[0207] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 135 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,780 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 86%.
[0208] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.30 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 89%.
[0209] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 16.0 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 86%.
[0210] Further, 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 resultant fabric was 136 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,480 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 84%.
EXAMPLE 9
[0211] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g) and terephthalic acid (252.7 g) were
added in 122% polyphosphoric acid (2,165.5 g) with stirring at
60.degree. C. for one hour, and the mixture was gradually heated so
as to be reacted at 120.degree. C. for 4 hours, at 135.degree. C.
for 20 hours and at 150.degree. C. for 5 hours. Further, to the
resultant oligomer dope, a dispersion obtained by adding
terephthalic acid (5.6 g) and copper phthalocyanine (19.5 g) in
122% polyphosphoric acid (74.4 g) was added, and the mixture was
allowed to react at 170.degree. C. for 5 hours and at 200.degree.
C. for 10 hours to obtain poly(p-phenylenebenzobisoxazole) dope
having an intrinsic viscosity of 29 dL/g at 30.degree. C., measured
using a methanesulfonic acid solution.
[0212] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0213] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 3
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,800 ppm, and that of sodium was
5,600 ppm; and the molar ratio of Na/P was 1.15.
[0214] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 86%.
[0215] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 84%.
[0216] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 86%.
[0217] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
88%.
[0218] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0219] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,150 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
85%.
[0220] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,670 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 83%.
[0221] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 136 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,790 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 82%.
[0222] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.30 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 82%.
[0223] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 15.0 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 84%.
[0224] Further, 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 resultant fabric was 135 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,560 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 82%.
EXAMPLE 10
[0225] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g) and terephthalic acid (252.7 g) were
added in 122% polyphosphoric acid (2,165.5 g) with stirring at
60.degree. C. for one hour, and the mixture was gradually heated so
as to be reacted at 120.degree. C. for 4 hours, at 135.degree. C.
for 20 hours and at 150.degree. C. for 5 hours. Further, to the
resultant oligomer dope, a dispersion obtained by adding
terephthalic acid (5.6 g) and copper phthalocyanine (5.6 g) in 122%
polyphosphoric acid (74.4 g) was added, and the mixture was allowed
to react at 170.degree. C. for 5 hours and at 200.degree. C. for 10
hours to obtain poly(p-phenylenebenzobisoxazole) dope having an
intrinsic viscosity of 30 dL/g at 30.degree. C., measured using a
methanesulfonic acid solution.
[0226] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0227] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,500 ppm, and that of sodium was
3,800 ppm; and the molar ratio of Na/P was 1.14.
[0228] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 82%.
[0229] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 81%.
[0230] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 82%.
[0231] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
84%.
[0232] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0233] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,380 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
82%.
[0234] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,760 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 83%.
[0235] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 135 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 6,040 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 81%.
[0236] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.30 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 78%.
[0237] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 14.6 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 81%.
[0238] Further, 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 resultant fabric was 134 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,770 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 78%.
EXAMPLE 11
[0239] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g) and terephthalic acid (252.7 g) were
added in 122% polyphosphoric acid (2,165.5 g) with stirring at
60.degree. C. for one hour, and the mixture was gradually heated so
as to be reacted at 120.degree. C. for 4 hours, at 135.degree. C.
for 20 hours and at 150.degree. C. for 5 hours. Further, to the
resultant oligomer dope, a dispersion obtained by adding
terephthalic acid (5.6 g) and copper phthalocyanine (41.1 g) in
122% polyphosphoric acid (74.4 g) was added, and the mixture was
allowed to react at 170.degree. C. for 5 hours and at 200.degree.
C. for 10 hours to obtain poly(p-phenylenebenzobisoxazole) dope
having an intrinsic viscosity of 28 dL/g at 30.degree. C., measured
using a methanesulfonic acid solution.
[0240] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0241] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,800 ppm, and that of sodium was
3,900 ppm; and the molar ratio of Na/P was 1.09.
[0242] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 87%.
[0243] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 87%.
[0244] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 88%.
[0245] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
89%.
[0246] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0247] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,380 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
86%.
[0248] Further, the spun yarns with-a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,560 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 85%.
[0249] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 138 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,590 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 86%.
[0250] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.29 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 85%.
[0251] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 15.3 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 85%.
[0252] Further, 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 resultant fabric was 137 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,310 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 84%.
EXAMPLE 12
[0253] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g), terephthalic acid (260.8 g),
quinacridone (19.2 g) and 122% polyphosphoric acid (2,078.2 g) were
stirred at 60.degree. C. for one hour, and the mixture was
gradually heated so as to be reacted at 135.degree. C. for 25
hours, at 150.degree. C. for 5 hours and at 170.degree. C. for 20
hours to obtain poly(p-phenylenebenzobisoxazole) dope having an
intrinsic viscosity of 24 dL/g at 30.degree. C., measured using a
methanesulfonic acid solution.
[0254] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0255] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,900 ppm, and that of sodium was
3,900 ppm; and the molar ratio of Na/P was 1.07.
[0256] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 85%.
[0257] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 83%.
[0258] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 84%.
[0259] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
87%.
[0260] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0261] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,120 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
84%.
[0262] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,610 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 83%.
[0263] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 136 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,830 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 81%.
[0264] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.30 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 82%.
[0265] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 15.0 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 84%.
[0266] Further, 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 resultant fabric was 135 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,500 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 82%.
COMPARATIVE EXAMPLE 1
[0267] Under a stream of a nitrogen gas, 4,6-diaminoresorcinol
dihydrochloride (334.5 g), terephthalic acid (260.8 g) and 122%
polyphosphoric acid (2,078.2 g) were stirred at 60.degree. C. for
one hour, and the mixture was gradually heated so as to be reacted
at 135.degree. C. for 25 hours, at 150.degree. C. for 5 hours and
at 170.degree. C. for 20 hours to obtain
poly(p-phenylenebenzobisoxazole) dope having an intrinsic viscosity
of 30 dL/g at 30.degree. C., measured using a methanesulfonic acid
solution.
[0268] After that, the resultant dope was spun to make filaments
each singly having a diameter of 11.5 .mu.m and a fineness of 1.5
denier. That is, the dope was extruded through a nozzle having 166
holes with diameters of 0.18 mm at 175.degree. C. to make the
filaments, which were then dipped and solidified in a first washing
bath so located as to converge the filaments at an appropriate
position to make a multi-filament. A quench chamber was provided in
an air gap between the nozzle and the first washing bath, so that
the filaments could be drawn long at an uniform temperature. The
quench temperature was 65.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 then wound onto resinous bobbins without drying. The
take-up rate was 200 m/minute.
[0269] The wound filament was neutralized with a 1% aqueous NaOH
solution for 10 seconds, and was then washed with water for 15
seconds, followed by drying at 80.degree. C. for 4 hours. The
concentrations of phosphorous and sodium remaining in the resultant
filaments were measured by the foregoing methods. As a result, the
concentration of phosphorous was 4,400 ppm, and that of sodium was
4,000 ppm; and the molar ratio of Na/P was 1.22.
[0270] The durability of the filament under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention thereof was 77%.
[0271] Six polybenzazole filaments thus obtained were doubled but
not twisted to make a yarn having a total fineness of 1,500
deniers. Such yarns were used to make a scrim filled with 5 warp
yarns/inch and 5 weft yarns/inch. The scrim was sandwiched between
two biaxially oriented polyester films with thickness of 12 microns
on each of which a polyurethane-based adhesive was applied, and the
lamination was cured and dried to make a sail cloth. The sail cloth
was cut out to obtain a cloth strip with a width of 2.5 cm and a
length of 50 cm, which included five reinforcing yarns. The
durability of the cloth strip under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the cloth strip was 76%.
[0272] Otherwise, six polybenzazole filaments thus obtained were
Z-wise twisted at a rate of 32 T/10 cm to make a Z-twisted yarn.
Two Z-twisted yarns obtained as above were S-wise twisted at a rate
of 32 T/10 cm to make a crude cord. The crude cord was subjected to
a two-staged dipping treatment to make a dip cord. The dipping
liquid for the first stage was an aqueous dispersion of an epoxy
resin, and the treating temperature was 240.degree. C. The dipping
liquid for the second stage was a RFL liquid, and the treating
temperature was 235.degree. C. The strength retention of the
resultant dip cord under an atmosphere of high temperature and high
humidity was 78%.
[0273] Otherwise, twelve polybenzazole filaments thus obtained were
twisted at a rate of 80 T/1 m to make a twisted union yarn having a
thickness of 3,000 deniers. Eight twisted union yarns thus obtained
were braided with a conventional machine to make a rope filled with
the eight twisted union yarns. The durability of the resultant rope
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the rope was
78%.
[0274] Otherwise, the polybenzazole filaments thus obtained were
cut into staple fibers with lengths of 51 mm. The resultant staple
fibers were spun at a twist coefficient of 3.5 to make a spun yarn
with a cotton yarn count of 20/1 Ne. Two such spun yarns were
twisted to make a two ply yarn with a cotton yarn count of 20/2
Ne.
[0275] The two ply yarns thus obtained were woven to make a 2/1
twill fabric filled with 68 warp yarns/inch and 60 weft yarns/inch.
The tensile strength of the resultant fabric in the vertical
direction was 4,270 N/3 cm. Then, the durability of the fabric
under an atmosphere of high temperature and high humidity was
evaluated. As a result, the strength retention of the fabric was
72%.
[0276] Further, the spun yarns with a cotton yarn count of 20/1 Ne
obtained as above were knitted to make a tubular knitted fabric
filled with 68 stitches/inch in the vertical direction and 29
stitches/inch in the lateral direction. The tensile strength of the
tubular knitted fabric in the vertical direction was 1,590 N/5 cm.
Then, the durability of the tubular knitted fabric under an
atmosphere of high temperature and high humidity was evaluated. As
a result, the strength retention of the fabric was 70%.
[0277] Further, the polybenzazole fiber yarns thus obtained were
woven with a rapier loom to make a plain weave fabric filled with
60 warp yarns/inch and 60 weft yarns/inch. The weight of the fabric
was 134 g/m.sup.2. The tensile strength of the fabric in the warp
yarn direction was 5,780 N/3 cm. The durability of the fabric under
an atmosphere of high temperature and high humidity was evaluated.
As a result, the strength retention of the fabric was 73%.
[0278] Further, four polybenzazole filaments thus obtained were
doubled but not twisted, to make a yarn having a total fineness of
1,000 deniers. The yarns thus obtained were used to make a
composite material by the foregoing method for making the sample of
a composite material. The content of the filaments in the resultant
composite material was 0.30 in terms of the volume ratio. The
durability of the composite material under an atmosphere of high
temperature and high humidity was evaluated. As a result, the
strength retention of the composite material was 73%.
[0279] Further, the staple fibers with lengths of 51 mm, cut from
the polybenzazole filaments thus obtained, were spun at a twist
coefficient of 3.5 to make a spun yarn with a cotton yarn count of
20 Ne. The tensile strength of the spun yarn was 9.3 cN/dtex. The
durability of the spun yarn under an atmosphere of high temperature
and high humidity was evaluated. As a result, the strength
retention of the spun yarn was 75%.
[0280] Further, 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 resultant fabric was 133 g/m.sup.2.
The tensile strength of the fabric in the warp yarn direction was
5,540 N/3 cm. The durability of the fabric under an atmosphere of
high temperature and high humidity was evaluated. As a result, the
strength retention of the fabric was 71%.
[0281] The foregoing results are summarized in Tables 1-3. As is
apparent from these Tables, the polybenzazole fibers of each
Example and the articles made thereof had a good durabilities under
an atmosphere of high temperature and high humidity, as compared
with the polybenzazole fibers of Comparative Example and the
articles made thereof. TABLE-US-00001 TABLE 1 Polybenzazole fiber
Durability under an Content of Initial Concentration Concentration
atmosphere of high pigment in strength of of phosphorous of sodium
in Na/P temperature and high filament filament CV in filament
filament (Molar ratio) humidity Kinds of pigment % GPa -- ppm ppm
-- % Example 1 Threne 5.0 5.8 0.047 4600 3600 1.05 86 Example 2
Copper 5.0 5.9 0.036 4500 2400 0.72 83 phthalocyanine Example 3
Copper 5.0 5.9 0.034 4400 3600 1.10 88 phthalocyanine Example 4
Copper 5.0 5.8 0.040 4700 5400 1.55 86 phthalocyanine Example 5
Copper 1.5 6.0 0.047 4500 4000 1.20 81 phthalocyanine Example 6
Copper 10 5.6 0.062 4400 3400 1.04 87 phthalocyanine Example 7
Copper 5.0 5.9 0.057 4600 2400 0.70 84 phthalocyanine Example 8
Copper 5.0 5.8 0.043 4900 4200 1.15 89 phthalocyanine Example 9
Copper 5.0 5.8 0.039 4800 5600 1.57 86 phthalocyanine Example 10
Copper 1.5 6.1 0.031 4500 3800 1.14 82 phthalocyanine Example 11
Copper 10 5.5 0.059 4800 3900 1.09 87 phthalocyanine Example 12
Quinacridone 5.0 5.7 0.039 4900 3900 1.07 85 Comparative -- 0 6.3
0.028 4400 4000 1.22 77 Example 1
[0282] TABLE-US-00002 TABLE 2 Woven fabric Knitted fabric Woven
fabric (Plain Sail cloth Dip cord Rope (Twill fabric) (Tubular
fabric) weave fabric, for knife-proof material) Durability
Durability Durability Fabric property Durability Fabric property
Durability Fabric property Weight Durability % % % N/3 cm % N/5 cm
% N/3 cm g/m.sup.2 % Example 1 87 89 87 4220 86 1660 85 5850 135 84
Example 2 82 85 85 4250 82 1710 80 5890 134 82 Example 3 90 91 90
4250 87 1670 85 5800 136 86 Example 4 86 87 88 4190 84 1660 83 5700
135 83 Example 5 82 83 81 4300 83 1740 83 5920 133 80 Example 6 89
85 88 4010 87 1590 85 5610 138 86 Example 7 81 86 86 4240 83 1690
82 5820 136 82 Example 8 88 91 92 4210 88 1660 85 5780 135 86
Example 9 84 86 88 4150 85 1670 83 5790 136 82 Example 10 81 82 84
4380 82 1760 83 6040 135 81 Example 11 87 88 89 3990 86 1560 85
5590 138 86 Example 12 83 84 87 4120 84 1610 83 5830 136 81
Comparative 76 78 78 4270 72 1590 70 5780 134 73 Example 1
[0283] TABLE-US-00003 TABLE 3 Composite material Spun yarn Woven
fabric (Plain weave Content of filaments in Initial strength
fabric, for bullet-proof material) composite material Durability of
filament Durability Fabric property Weight Durability Volume ratio
% cN/dtex % N/3 cm g/m.sup.2 % Example 1 0.29 82 15.3 84 5600 135
83 Example 2 0.30 80 14.8 81 5580 136 80 Example 3 0.30 87 15.8 85
5620 135 85 Example 4 0.30 83 15.1 84 5550 136 82 Example 5 0.29 79
14.5 80 5690 133 79 Example 6 0.31 85 15.5 85 5280 138 84 Example 7
0.29 81 15 83 5500 135 80 Example 8 0.30 89 16 86 5480 136 84
Example 9 0.30 82 15 84 5560 135 82 Example 10 0.30 78 14.6 81 5770
134 78 Example 11 0.29 85 15.3 85 5310 137 84 Example 12 0.30 82 15
84 5500 135 82 Comparative 0.30 73 9.3 75 5540 133 61 Example 1
INDUSTRIAL APPLICABILITY
[0284] According to the present invention, there can be provide
polybenzazole fibers which can sufficiently maintain the strength
thereof even when exposed to an atmosphere of high temperatures and
high humidity for a long period of time after yarns made thereof
have had kink bands therein. Therefore, the use of the
polybenzazole fibers can enhance the practical performance in the
applications where the fibers are processed to woven fabrics,
knitted fabrics, braids, ropes, cords and the like, which include,
for example, tension materials such as cables, tension members
(electric wires, optical fibers and the like) and ropes, high
shock-proof members such as bullet-proof materials, cutting-proof
members such as gloves, rubber-reinforcing materials such as belts,
tires, shoe soles, ropes and hoses.
* * * * *