U.S. patent application number 14/007703 was filed with the patent office on 2014-01-16 for liquid crystal polyester fibers and method for producing same.
This patent application is currently assigned to Toray Industries, Inc.. The applicant listed for this patent is Yoshitsugu Funatsu, Hiroo Katsuta, Chieko Kawamata, Yusuki Ono. Invention is credited to Yoshitsugu Funatsu, Hiroo Katsuta, Chieko Kawamata, Yusuki Ono.
Application Number | 20140017965 14/007703 |
Document ID | / |
Family ID | 46930589 |
Filed Date | 2014-01-16 |
United States Patent
Application |
20140017965 |
Kind Code |
A1 |
Kawamata; Chieko ; et
al. |
January 16, 2014 |
LIQUID CRYSTAL POLYESTER FIBERS AND METHOD FOR PRODUCING SAME
Abstract
Provided are liquid crystal polyester fibers having a running
tension variable width (R) of 5 cN or less and an oil component
deposition rate of 3.0 wt % or less. Also provided is a method for
producing liquid crystal polyester fibers whereby solid-phase
polymerization is performed after applying inorganic particles (A)
and phosphoric acid compound (B) to yarn obtained by melt spinning
of liquid crystal polyester. Further provided is a mesh textile
formed from the liquid crystal polyester fibers. By means of the
liquid crystal polyester fibers, method for producing the same, and
mesh textile, step transition and product yield during the weaving
steps are excellent in that there is little scum and there is
little variation of the running tension during the weaving
steps.
Inventors: |
Kawamata; Chieko;
(Mishima-shi, JP) ; Ono; Yusuki; (Mishima-shi,
JP) ; Katsuta; Hiroo; (Mishima-shi, JP) ;
Funatsu; Yoshitsugu; (Mishima-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kawamata; Chieko
Ono; Yusuki
Katsuta; Hiroo
Funatsu; Yoshitsugu |
Mishima-shi
Mishima-shi
Mishima-shi
Mishima-shi |
|
JP
JP
JP
JP |
|
|
Assignee: |
Toray Industries, Inc.
Tokyo
JP
|
Family ID: |
46930589 |
Appl. No.: |
14/007703 |
Filed: |
March 12, 2012 |
PCT Filed: |
March 12, 2012 |
PCT NO: |
PCT/JP2012/056247 |
371 Date: |
September 26, 2013 |
Current U.S.
Class: |
442/49 ; 264/13;
528/193 |
Current CPC
Class: |
D06M 2101/32 20130101;
D02J 13/001 20130101; D06M 13/292 20130101; D01F 6/62 20130101;
D06M 23/08 20130101; D06M 11/79 20130101; D01F 6/84 20130101; Y10T
442/183 20150401; B29D 99/0078 20130101; C08G 63/40 20130101; D10B
2331/04 20130101 |
Class at
Publication: |
442/49 ; 264/13;
528/193 |
International
Class: |
D01F 6/62 20060101
D01F006/62; C08G 63/40 20060101 C08G063/40; B29D 99/00 20060101
B29D099/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2011 |
JP |
2011-072020 |
Mar 30, 2011 |
JP |
2011-076158 |
Dec 1, 2011 |
JP |
2011-263399 |
Claims
1. A liquid crystalline polyester fiber exhibiting a running
tension fluctuation range (R) of 5 cN or less and an oil adhesion
rate of 3.0 wt % or less.
2. The liquid crystalline polyester fiber according to claim 1,
wherein an amount of scum associated with the fiber is 0.01 g or
less for 100,000 m of fiber generated at a rate of 400 m/min.
3. The liquid crystalline polyester fiber according to claim 1
whose strength is 12.0 cN/dtex or more.
4. The liquid crystalline polyester fiber according to claim 1,
wherein a half width of an endothermic peak (Tm.sub.1) observed
when measured under a condition of heating from 50.degree. C. at a
temperature elevation rate of 20.degree. C./min in differential
calorimetry is 15.degree. C. or higher.
5. The liquid crystalline polyester fiber according to claim 1
which is a monofilament.
6. The liquid crystalline polyester fiber according to claim 1
which is composed of a single polymer component.
7. The liquid crystalline polyester fiber according to claim 1,
wherein the liquid crystalline polyester is composed of the
following structural units (I), (II), (III), (IV), and (V)
##STR00007##
8. A method of producing a liquid crystalline polyester fiber
comprising subjecting a yarn prepared by melt spinning a liquid
crystalline polyester to a solid-phase polymerization after
applying inorganic particles (A) and a phosphate-based compound (B)
to said yarn.
9. The method according to claim 8, further comprising cleaning
said liquid crystalline polyester fiber after said solid-phase
polymerization.
10. The method according to claim 9, further comprising carrying
out a high temperature heat treatment at a temperature of an
endothermic peak temperature (Tm.sub.1) of said liquid crystalline
polyester fiber after said cleaning +10.degree. C. or higher.
11. The method according to claim 8, wherein said inorganic
particles (A) are one or more selected from silica and
silicates.
12. The method according to claim 8, wherein said phosphate-based
compound (B) comprises any of compounds represented by Formulae (1)
to (3) or a combination thereof, and satisfies Conditions 1 to 4:
##STR00008## Condition 1: R.sub.1 and R.sub.2 represent a
hydrocarbon group; Condition 2: M.sub.1 represents an alkali metal;
Condition 3: M.sub.2 represents a group selected from an alkali
metal, a hydrogen atom, a hydrocarbon group and a hydrocarbon group
containing an oxygen atom(s); Condition 4: n represents an integer
of 1 or more.
13. A mesh woven fabric comprising said liquid crystalline
polyester fiber according claim 1.
14. A mesh woven fabric comprising said liquid crystalline
polyester fiber according to claim 2.
15. A mesh woven fabric comprising said liquid crystalline
polyester fiber according to claim 3.
16. A mesh woven fabric comprising said liquid crystalline
polyester fiber according to claim 4.
17. A mesh woven fabric comprising said liquid crystalline
polyester fiber according to claim 5.
18. A mesh woven fabric comprising said liquid crystalline
polyester fiber according to claim 6.
19. A mesh woven fabric comprising said liquid crystalline
polyester fiber according to claim 7.
Description
TECHNICAL FIELD
[0001] The present invention relates to a liquid crystalline
polyester fiber that exhibits high strength and high elastic
modulus and is excellent in process passability, and a method of
producing the liquid crystalline polyester fiber.
BACKGROUND ART
[0002] It is known that a liquid crystalline polyester is a polymer
comprising a rigid molecular chain, and highest strength and
elastic modulus can be obtained among fibers prepared by melt
spinning by highly orienting the molecular chain in the fiber axis
direction in the melt spinning and further carrying out solid phase
polymerization. Further, it is also known that the liquid
crystalline polyester can be improved in thermal resistance and
dimensional stability by solid phase polymerization because the
molecular weight increases and the melting point elevates by solid
phase polymerization (see, for example, Non-Patent Document 1).
Thus, in a liquid crystalline polyester fiber, the high strength,
high elastic modulus, and excellent thermal resistance and thermal
dimensional stability are exhibited by carrying out solid phase
polymerization. Here, a solid-phase polymerization reaction is
generally carried out at high temperatures around the melting
point. Because of this, fusion bonding between yarns tends to take
place. For the purpose of preventing the fusion bonding causing
deteriorated characteristics and fibrillation of the yarn, it is an
important point of technique in the production of the liquid
crystalline polyester fiber to add a solid-phase polymerization oil
agent.
[0003] Meanwhile, the solid-phase polymerization oil agent remains
on the fiber surface after the solid-phase polymerization and in
turn accumulates on guides, rollers, or tension providers in post
processing steps of fibers, for example, a weaving step, thereby
generating waste called scum. Because contamination of this scum
into products causes product defects or yarn breakage by increased
tension fluctuation, it is also an important point of technique in
the production of the liquid crystalline polyester fiber to clean
and remove the solid-phase polymerization oil agent after the
solid-phase polymerization.
[0004] As this solid-phase polymerization oil agent, fluorine-based
or silicone-based organic compounds with thermal resistance have
been employed thus far. What has been proposed is, for example,
utilization of polydimethylsiloxane which is water emulsifiable,
easy to applied to the fiber surface and thermal resistable at high
temperatures (Patent Documents 1 and 2). That is, according to
Patent Documents 1 and 2, a liquid crystalline polyester fiber
exhibiting a very low amount of oil adhesion is obtained by
applying polydimethylsiloxane with high thermal resistance as a
solid-phase polymerization oil agent and carrying out a
cleaning-heat treatment after the solid-phase polymerization.
[0005] Further, also known is a technique of utilizing inorganic
particles with thermal resistance, instead of the used of the
organic compound, as solid-phase polymerization oil agent (Patent
Document 3).
PRIOR ART REFERENCES
Patent Documents
[0006] Patent Document 1: Japanese Patent Application Laid-Open
Publication No. 2010-209495 (sixth and seventh pages) [0007] Patent
Document 2: Japanese Patent Application Laid-Open Publication No.
2010-248681 (eleventh page) [0008] Patent Document 3: Japanese
Patent Application Laid-Open Publication No. 2011-168930 (second
and eighth pages)
Non-Patent Documents
[0008] [0009] Non-Patent Document 1: Edit by Technical Information
Association, "Modification of Liquid Crystalline Polymer and Recent
Applied Technology" (2006) (pages 235-256)
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0010] It was revealed that, because polydimethylsiloxane used in
the above method of production described in Patent Documents 1 and
2 caused gelling by cross-linking reaction among
polydimethylsiloxane under conditions of the solid-phase
polymerization and the gelled product solidly adhered to the fiber
surface, polydimethylsiloxane remained on the fiber even after
mechanical cleaning such as ultrasonic cleaning in addition to
cleaning by surfactants. That is, an amount of oil adhesion in the
above documents was calculated from yarn weight (W.sub.0) before
the cleaning and yarn weight (W.sub.1) after the ultrasonic
cleaning using the following equation, and it was found that,
because the gelled product was not completely dropped off at the
time of the ultrasonic cleaning, although the amount of adhesion of
a solid-phase polymerization oil agent was calculated as a low
value, the gelled product of solid-phase polymerization oil agent
whose amount could not be measured as the amount of oil adhesion
firmly adhered and remained on the fiber.
Amount of oil adhesion (wt
%)=(W.sub.0-W.sub.1).times.100/W.sub.1
[0011] Due to this, according to the method of production described
in Patent Documents 1 and 2, a yarn hold very low amount of oil
adhesion by strengthening the cleaning in the cleaning step after
the solid-phase polymerization. In addition, although, in Examples,
effects of suppressing generation of scum and contamination of the
scum into the product were confirmed in a weaving step in which a
small amount of liquid crystalline polyester fiber was picked to
weave as welf, a very small amount of scum was generated, and when
extended evaluation was carried out, it was revealed that tension
fluctuation by accumulation of the gelled product onto guides,
tension providers or the like increased with time; and yarn
breakage or contamination of the scum into the product
occurred.
[0012] Further, in Patent Document 3, a fiber is applied with
swelling clay minerals having properties of swelling and dispersing
in water and subjected to solid-phase polymerization. The fiber is
immersed in water after the solid-phase polymerization, which
enabled dropping solid-phase polymerization oil agent. However,
when such inorganic particles are solely applied on the fiber, or
dispersed in a common spinning oil agent or the like and then
applied on the fiber, the inorganic particles were firmly adhered
on the fiber surface after the solid-phase polymerization step.
Thus, similarly to the above examples of polydimethylsiloxane,
although the fiber had a very amount of oil adhesion after the
cleaning, the inorganic particles dropped off by being scratched by
guides or tension providers in the weaving step, which caused
occurrence of tension fluctuations or product defects by product
contamination.
[0013] As mentioned above, a solid-phase polymerization oil agent
for the liquid crystalline polyester fiber that has both effects
for suppressing fusion bonding and excellent cleaning properties
has not been developed thus far. Thus, a liquid crystalline
polyester fiber that is industrially utilizable with suppressed
scum generation and tension fluctuation in the weaving step, and is
excellent in process passability and product yield; and production
technique thereof have not been proposed. The development thereof
has been wanted.
[0014] An object of the present invention is to provide a liquid
crystalline polyester fiber that has a small amount of deposit
(scum) in the weaving step, small fluctuation of running tension,
and is excellent in process passability and product yield in the
weaving step; as well as a method of production thereof and a mesh
woven fabric thereof.
Means for Solving the Problem
[0015] To solve the above problem, a liquid crystalline polyester
fiber of the present invention is composed of the following. That
is,
the liquid crystalline polyester fiber is a liquid crystalline
polyester fiber exhibiting a running tension fluctuation range (R)
of 5 cN or less and an oil adhesion rate of 3.0 wt % or less.
[0016] To solve the above problem, a method of producing a liquid
crystalline polyester fiber of the present invention is composed of
the following. That is, the method is a method of producing a
liquid crystalline polyester fiber comprising applying inorganic
particles (A) and a phosphate-based compound (B) to a liquid
crystalline polyester yarn prepared by melt spinning, followed by
solid-phase polymerization.
[0017] To solve the above problem, a mesh woven fabric of the
present invention is composed of the following. That is,
the mesh fabric is a mesh woven fabric comprising the above liquid
crystalline polyester fiber.
[0018] In the present invention, an amount of scum generated by the
liquid crystalline polyester fiber is preferably 0.01 g or
less.
[0019] In the present invention, the strength of the liquid
crystalline polyester fiber is preferably 12.0 cN/dtex or more.
[0020] In the liquid crystalline polyester fiber of the present
invention, a half width of an endothermic peak (Tm.sub.1) observed
when measured under a condition of heating from 50.degree. C. at a
temperature elevation rate of 20.degree. C./min in differential
calorimetry is preferably 15.degree. C. or higher.
[0021] The liquid crystalline polyester fiber of the present
invention is preferably a monofilament.
[0022] The liquid crystalline polyester fiber of the present
invention is preferably composed of a single polymer component.
[0023] The liquid crystalline polyester fiber of the present
invention, the liquid crystalline polyester is preferably composed
of the following structural units (I), (II), (III), (IV), and
(V).
##STR00001##
[0024] The method of producing the liquid crystalline polyester
fiber of the present invention preferably comprises cleaning the
liquid crystalline polyester fiber after the solid-phase
polymerization.
[0025] The method of producing the liquid crystalline polyester
fiber of the present invention preferably comprises carrying out a
high temperature heat treatment at a temperature of an endothermic
peak temperature (Tm.sub.1) of said liquid crystalline polyester
fiber after said cleaning +10.degree. C. or higher.
[0026] In the method of producing the liquid crystalline polyester
fiber of the present invention, the inorganic particles (A) are one
or more selected from silica and silicates.
[0027] In the method of producing the liquid crystalline polyester
fiber of the present invention, the phosphate-based compound (B)
preferably comprises any of compounds represented by the following
chemical formulae (1) to (3) or a combination thereof, and
satisfies the following conditions 1 to 4.
##STR00002##
[0028] Condition 1: R.sub.1 and R.sub.2 represent a hydrocarbon
group.
[0029] Condition 2: M.sub.1 represents an alkali metal.
[0030] Condition 3: M.sub.2 represents a group selected from an
alkali metal, a hydrogen atom, a hydrocarbon group and a
hydrocarbon group containing an oxygen atom(s).
[0031] Condition 4: n represents an integer of 1 or more.
Effect of the Invention
[0032] Because the liquid crystalline polyester fiber according to
the present invention exhibits small fluctuation of running
tension, yarn breakage ascribed to tension fluctuation in
high-order processing of fibers such as knit weaving is suppressed
and thus the fiber is excellent in process passability, allows for
densification of weave density, and can improve weavability.
Further, product defects by tight picks of a product or
contamination of scum can be suppressed, thereby improving product
yield. In particular for applications for filters and screen gauzes
which require high-mesh woven fabrics, what can be attained are to
densify weave density (to make a mesh higher) for improving
performance, to make an opening area larger, to decrease the
defects of the openings, and to improve weavability.
[0033] By the method of producing the liquid crystalline polyester
fiber according to the present invention, a fiber capable of
providing a liquid crystalline polyester fiber which has high
strength and high elastic modulus, has a small amount of deposit
(scum) in a weaving step, exhibits small fluctuation of running
tension, is excellent in process passability, and thereby shows
markedly improved product yield of woven fabric. In such a method
of production, by further cleaning a liquid crystalline polyester
fiber after solid-phase polymerization, solid-phase polymerization
oil agent can be readily removed. As seen above, by carrying out
the cleaning, the liquid crystalline polyester fiber of markedly
improved process stability in the weaving step and product yield as
described above can be obtained.
MODES FOR CARRYING OUT THE INVENTION
[0034] A liquid crystalline polyester fiber according to the
present invention will be described in detail below.
[0035] The liquid crystalline polyester used in the present
invention is a polyester capable of forming an anisotropic melting
phase (showing a liquid crystal property) when molten. These
characteristics can be recognized, for example, by placing a sample
of a liquid crystalline polyester on a hot stage, heating it under
a nitrogen atmosphere, and observing a transmitted light of the
sample under a polarized radiation.
[0036] Examples of the liquid crystalline polyester used in the
present invention include (i) a polymer of an aromatic
oxycarboxylic acid; (ii) a polymer of an aromatic dicarboxylic acid
with an aromatic diol or an aliphatic diol; and (iii) a copolymer
comprising an aromatic oxycarboxylic acid, an aromatic dicarboxylic
acid and an aromatic diol or an aliphatic diol. Of these a polymer
that is solely composed of aromatic series is preferred. The
polymer that is solely composed of aromatic series develops
excellent strength and elastic modulus when made into a fiber.
Further, common methods including conventionally known methods can
be employed for polymerization formulation of liquid crystalline
polyester.
[0037] Examples of the aromatic oxycarboxylic acid include hydroxy
benzoic acid, hydroxy naphthoic acid; and an alkyl, alkoxy or
halogen substituted product thereof.
[0038] Further, examples of the aromatic dicarboxylic acid include
terephthalic acid, isophthalic acid, diphenyl dicarboxylic acid,
naphthalene dicarboxylic acid, diphenylether dicarboxylic acid,
diphenoxyethane dicarboxylic acid, diphenylethane dicarboxylic
acid; and an alkyl, alkoxy or halogen substituted product
thereof.
[0039] Further, examples of the aromatic diol include hydroquinone,
resorcinol, dihydroxybiphenyl, naphthalene diol, and an alkyl,
alkoxy or halogen substituted product thereof. Examples of the
aliphatic diol include ethylene glycol, propylene glycol, butane
diol, and neopentyl glycol.
[0040] Examples of preferred liquid crystalline polyesters used in
the present invention include a liquid crystalline polyester with
p-hydroxy benzoic acid component and 6-hydroxy 2-naphthoic acid
component being copolymerized; a liquid crystalline polyester with
p-hydroxy benzoic acid component, 4,4'-dihydroxy biphenyl
component, and isophthalic acid component and/or terephthalic acid
component being copolymerized; and a liquid crystalline polyester
with p-hydroxy benzoic acid component, 4,4'-dihydroxy biphenyl
component, isophthalic acid component, terephthalic acid component
and hydroquinone component being copolymerized.
[0041] The combination of shown above decreases the symmetric
property of a molecular chain, thereby lowering the melting point
of liquid crystalline polyester to or below the decomposition point
and allows the liquid crystalline polyester to have the melting
point at which melt spinning is feasible. Therefore, a good yarn
formation property can be exhibited at a spinning temperature set
between the melting point and the thermal decomposition temperature
of the polymer, a fiber uniform in the lengthwise direction can be
obtained, and because of an appropriate crystallinity, the strength
and elastic modulus of the fiber can be increased. In the present
invention, a liquid crystalline polyester comprising the structural
units (I), (II), (III), (IV) and (V) represented by the following
chemical formula is preferred.
##STR00003##
[0042] It is noted that the "structural unit" in the present
invention refers to a unit capable of composing a repeated
structure in a main chain of a polymer. The above combination of
(I) to (V) is preferred in that it renders high linearity and
thereby the elastic modulus can be increased.
[0043] By combining components comprising diols with a high
linearity and a small bulk such as the structural units (II) and
(III), the molecular chain can have an orderly structure with less
disorder, and an interaction in a direction perpendicular to the
fiber axis can be maintained because the crystallinity is not
increased excessively. By this, in addition to obtain high strength
and elastic modulus, a particularly excellent abrasion resistance
can be obtained by carrying out a high temperature heat treatment
after solid-phase polymerization.
[0044] Further, the above structural unit (I) preferably accounts
for 40 to 85 mol % relative to the sum of the structural units (I),
(II) and (III), more preferably 65 to 80 mol %, and still more
preferably 68 to 75 mol %. By control in such a range, moderate
crystallinity is achieved, results in high strength and elastic
modulus and moderate melting point where the melt spinning is
feasible.
[0045] The structural unit (II) preferably accounts for 60 to 90
mol % relative to the sum of the structural units (II) and (III),
more preferably 60 to 80 mol %, and still more preferably at 65 to
75 mol %. By control in such a range, since the crystallinity does
not increase excessively and the interaction in a direction
perpendicular to the fiber axis can be maintained, the abrasion
resistance can be improved by carrying out a high temperature heat
treatment after solid-phase polymerization.
[0046] The structural unit (IV) preferably accounts for 40 to 95
mol % relative to the sum of the structural units (IV) and (V),
more preferably 50 to 90 mol %, and still more preferably at 60 to
85 mol %. Because such a range allows the melting point of the
polymer to be an appropriate range and, having good spinning
ability at spinning temperature that is set between melting point
and thermal decomposition temperature of the polymer, a fiber with
uniformity in the lengthwise direction can be obtained. In addition
to this, because the linearity of the polymer is moderately
destroyed, the interaction in a direction perpendicular to the
fiber axis can be enhanced and the abrasion resistance can be
improved by a high temperature heat treatment after solid-phase
polymerization.
[0047] Preferred ranges of the each of the structural units of the
above liquid crystalline polyester that are preferably used in the
present invention are as follows. Note that the sum of the
following structural units (I) to (V) is 100 mol %. The liquid
crystalline polyester fiber according to the present invention can
be suitably obtained by controlling the composition in these
ranges.
[0048] Structural unit (I): 45 to 65 mol %
[0049] Structural unit (II): 12 to 18 mol %
[0050] Structural unit (III): 3 to 10 mol %
[0051] Structural unit (IV): 5 to 20 mol %
[0052] Structural unit (V): 2 to 15 mol %
Further, it is preferable the total amount of the structural unit
(IV) and (V) and the total amount of the structural unit (II) and
(III) are substantially same in terms of mole.
[0053] In the liquid crystalline polyester used in the present
invention, besides the above monomers, other monomers can be
further copolymerized in a range where the liquid crystallinity is
not impaired; and examples of other monomers include aromatic
dicarboxylic acid such as adipic acid, azelaic acid, sebacic acid,
or dodecanedionic acid; alicyclic dicarboxylic acid such as
1,4-cyclohexane dicarboxylic acid; polyether such as polyethylene
glycol; polysiloxane; aromatic iminocarboxylic acid; aromatic
diimine; and aromatic hydroxydiimine.
[0054] Further, in the liquid crystalline polyester used in the
present invention, other polymers can be added or combined to use
in a range where the effects of the present invention are impaired.
Addition or combination use refers to, in the case of mixing
polymers or in a composite spinning yarn with two or more
components, partially mixed used or complete use of other polymers
as one component or plural components. As another polymer, a
polyester, a vinyl-group polymer such as a polyolefine or a
polystyrene, a polycarbonate, a polyamide, a polyimide, a
polyphenylene sulfide, a polyphenylene oxide, a polysulfone, an
aromatic polyketone, an aliphatic polyketone, a semi-aromatic
polyester amide, a polyetheretherketone, or a fluoro resin may be
added, suitable examples include polyphenylene sulfide,
polyetheretherketone, nylon 6, nylon 66, nylon 46, nylon 6T, nylon
9T, polyethylene terephthalate, polypropylene terephthalate,
polybutylene terephthalate, polyethylene naphthalate,
polycyclohexane dimethanol terephthalate, and polyester 99M. In
case where these polymers are added or combined to use, the melting
point thereof is preferably set within the melting point of the
liquid crystalline polyester .+-.30.degree. C. because the yarn
formation property is not impaired. In order to improve the
strength, elastic modulus of the obtained fiber and to suppress
fluff generation by detachment at polymer interface and yarn
breakage, the amount added or combined to use is preferably 50 wt %
or less, and more preferably 5 wt % or less. It is still more
preferred that other polymers be substantially not added or
combined to use.
[0055] In the liquid crystalline polyester used in the present
invention, in a range where the effects of the present invention
are not impaired, a small amount of various additives may be
contained, such as an inorganic substance such as various metal
oxides, kaoline and silica, a colorant, a delustering agent, a
flame retardant, an anti-oxidant, an ultraviolet ray absorbent, an
infrared ray absorbent, a crystalline nucleus agent, a fluorescent
whitening agent, an end group closing agent, or a compatibility
providing agent.
[0056] A fiber according to the present invention refers to a yarn
that is spun by a common melt spinning method.
[0057] In the liquid crystalline polyester fiber of the present
invention, a fluctuation range of running tension (R) is 5 cN or
less and preferably 4 cN or less. The fluctuation range of running
tension (R) that is referred here is a value obtained by a method
described in Section A in Examples. The present inventors paid
attention to tension fluctuation as a factor that significantly
affects process passability and product yield in a high-order step
such as weaving a liquid crystalline polyester fiber or the like,
and intensively studied to find out that there is good correlation
between a fluctuation range of running tension (R) obtained by a
method described in Section A in Examples, and process passability
and product yield in a high-order processing step such as weaving.
That is, with the fluctuation range of running tension (R)
satisfying 5 cN or less, the tension fluctuation is particularly
suppressed in production of woven fabric and the process
passability in the weaving step dramatically improves.
[0058] Further, if the fluctuation range of running tension (R)
exceeds 5 cN, a large fluctuation of running tension induce uneven
tension of liquid crystalline polyester fiber in steps at the time
of weaving step, thereby leading to deterioration of the process
passability or product defects of the obtained woven fabric to
cause a decrease in the product yield.
[0059] A method of making the fluctuation range of running tension
(R) to 5 cN or less is not particularly restricted. For example, as
described in a method of production that is described later, the
fluctuation range of running tension (R) to 5 cN or less can be
attained by subjecting the liquid crystalline polyester fiber to
solid-phase polymerization after applying inorganic particles (A)
and phosphate-based compound (B) and then cleaning the obtained
fiber.
[0060] In the fiber of the present invention, an oil adhesion rate
is 3.0 wt % or less. The oil adhesion rate that is referred here is
a total adhesion rate of residual solid-phase polymerization oil
agent and finishing oil agent remained on fibers after the
cleaning, and refers to a value determined by a method described in
Section D in Examples. With the oil adhesion rate being 3.0 wt % or
less, the number of times of machine stopping can be reduced in
post processing steps to improve weavability, wherein the machine
stopping is caused by yarn breakage ascribed to aggregation and
false adhere of fibers or for cleaning oil agent pollution. If the
oil adhesion rate exceeds 3.0 wt %, aggregation of yarns ascribed
to oil agents that are excessively adhered frequently occurs and
the excessive oil agent falls off by scratch in the step to pollute
stations. Further, from the viewpoint of preventing yarn breakage
ascribed to the oil agent or station pollution to improve
weavability, the oil adhesion rate is more preferably 2.0 wt % or
less and still more preferably 1.5 wt % or less. The lower limit
thereof is not particularly restricted. A finishing oil agent is
usually added to the fiber for exerting effects such as lubricity
in weaving. From the viewpoint of preventing scrape of the fiber in
the weaving, the lower limit of the oil adhesion rate, which is a
total adhesion rate residual solid-phase polymerization oil agent
and finishing oil agent is, although it depends on the type of oil
agent, usually about 0.5 wt % and more preferably 0.8 wt % or
more.
[0061] In the liquid crystalline polyester fiber of the present
invention, the amount of scum generated is preferably 0.01 g or
less for the viewpoint of suppressing scum generation in the
weaving step to keep process stability, and suppressing
contamination of scum into a product to improve product yield. It
is more preferably 0.002 g or less. The amount of scum generated
that is referred here is a value obtained by a method described in
Section H in Examples. The lower limit of the amount of scum
generated is not particularly restricted, and it is practically
about 0.0001 g from the viewpoint of balance between effort and
effect in cleaning.
[0062] A method of making the amount of scum generated is 0.01 g or
less is not particularly restricted. For example, as described in a
method of production that is described later, the amount of scum
generated is 0.01 g or less can be attained by subjecting the
liquid crystalline polyester fiber to solid-phase polymerization
after applying inorganic particles (A) and phosphate-based compound
(B) and then cleaning the obtained fiber.
[0063] The number of filaments of the fiber of the present
invention can be freely selected and is preferably 50 or less, more
preferably 20 or less to make a fiber product thinner or lighter in
weight. In particular, because a monofilament whose filament number
is one is a field in which suppressed scum generation and stable
running tension are required, it can be in particular used
suitably.
[0064] The single-fiber fineness of the fiber of the present
invention is preferably 18.0 dtex or less. The single-fiber
fineness that is referred here is a value determined by a method
described in Section B in Examples. By making the fiber thinner at
a single-fiber fineness of 18.0 dtex or less, the molecular weight
of the polymer is easy to increase when polymerized in solid phase
at fibrous state, and the strength, elongation and elastic modulus
improved. Provided are advantages that the flexibility of the fiber
increases and the processability of the fiber improves, that the
surface area increases and therefore the adhesion property thereof
with a chemical solution such as an adhesive improves, and in case
of being formed as a gauze comprising monofilaments, that the
thickness can be thinned, that the weave density can be increased,
and that the opening (area of the opening portions) can be widened.
The single-fiber fineness is more preferably 10.0 dtex or less, and
still more preferably 7.0 dtex or less. Although the lower limit of
the single-fiber fineness is not particularly restricted, a lower
limit that can be achieved by a method of production described
later is about 1.0 dtex.
[0065] For improved strength of a final product such as woven
fabric or knit, the strength of the fiber of the present invention
is preferably 12.0 cN/dtex or more, more preferably 14.0 cN/dtex or
more, and still more preferably 15.0 cN/dtex or more. Although the
upper limit of the strength is not particularly restricted, the
upper limit that can be achieved by a method of production
described later is about 40.0 cN/dtex. The strength that is
referred here is a value determined by a method described in
Section C in Examples.
[0066] The elongation of the fiber of the present invention is
preferably 1.0% or more and more preferably 2.0% or more. With the
elongation being 1.0% or more, the impact absorbability of the
fiber is improved, the process passability in high-order processing
steps and the ease of handling are excellent, and in addition,
because the impact absorbability is improved, the abrasion
resistance is improved as well. Although the upper limit of the
elongation is not particularly restricted, the upper limit that can
be achieved by a method of production described later is about
10.0%. The elongation that is referred here is a value determined
by a method described in Section C in Examples.
[0067] Further, in order to increase the elastic modulus of woven
fabrics, the elastic modulus is preferably 500 cN/dtex or more,
more preferably 600 cN/dtex or more, and still more preferably 700
cN/dtex or more. Although the upper limit of the elastic modulus is
not particularly restricted, the upper limit that can be achieved
by a method of production described later is about 1,500 cN/dtex.
The elastic modulus that is referred in the present invention is a
value determined by a method described in Section C in
Examples.
[0068] Because of the high strength and elastic modulus, it can be
suitably used in applications, such as ropes, fibers for
reinforcing members such as a tension member, screen gauzes for
printing and mesh woven fabrics for filters.
[0069] In the liquid crystalline polyester fiber of the present
invention a half width of an endothermic peak (Tm.sub.1) observed
when measured under a condition of heating from 50.degree. C. at a
temperature elevation rate of 20.degree. C./min in differential
calorimetry is preferably 15.degree. C. or above. Tm.sub.1 in this
determination method represents a melting point of fiber, and
relating to the peak shape, the wider the area of the peak, that
is, the greater the heat of melting (.DELTA.Hm.sub.1) is, the
higher the degree of crystallization is, and the smaller the half
width is, the higher the completion of crystallinity is. In the
liquid crystalline polyester, by carrying out solid phase
polymerization after spinning, Tm.sub.1 elevates, .DELTA.Hm.sub.1
increases and the half width decreases, that is, the degree of
crystallization and the completion of crystallinity increase, and
the strength and elastic modulus of the fiber are increased and the
thermal resistance thereof is improved. On the other hand, although
the abrasion resistance deteriorates, this is considered because a
difference in structure between the crystal part and the amorphous
part becomes remarkable by increase of the completion of
crystallinity and therefore destruction occurs in the interface
therebetween. Accordingly, in the fiber of the present invention,
it is preferred that the liquid crystallinity be decreased by
increasing the half width of the peak up to a value of 15.degree.
C. such as one of a liquid crystalline polyester fiber which is not
carried out with solid phase polymerization while maintaining a
high Tm.sub.1 and high strength, elongation, elastic modulus and
thermal resistance that are the features of a fiber carried out
with solid phase polymerization, and the abrasion resistance can be
improved by decreasing the difference in structure between the
crystal/amorphous parts which becomes a trigger of the destruction,
disarraying the fibril structure, and softening the whole of the
fiber. The higher the half width of peak at Tm.sub.1 is, the higher
the abrasion resistance is. Thus, the half width of peak at
Tm.sub.1 is preferably 20.degree. C. or more. Although the upper
limit is not particularly restricted, the upper limit that can be
industrially achieved is about 80.degree. C.
[0070] It is noted that, in the liquid crystalline polyester fiber
of the present invention, although the endothermic peak is one, two
or more peaks may be observed depending on the fiber structure, for
example, in the case of inadequate solid phase polymerization. In
this case, the half width of peak refers to a value of the sum of
the half width of each peak.
[0071] The melting point (Tm.sub.1) of the fiber of the present
invention is preferably 300.degree. C. or higher, more preferably
310.degree. C. or higher, and still more preferably 320.degree. C.
or higher. By having such a high melting point, the thermal
resistance and thermal dimensional stability are excellent and thus
processing can be carried out at high temperatures even after
completing a product, thereby leading to excellent post
processability. Although the upper limit of Tm.sub.1 is not
particularly restricted, an upper limit that can be achieved in the
present invention is about 400.degree. C.
[0072] Further, the value of the heat of melting .DELTA.Hm.sub.1
varies depending on the composition of the structural unit of the
liquid crystalline polyester, and is preferably 6.0 J/g or less. By
decreasing .DELTA.Hm.sub.1 to 6.0 J/g or less leads to reduction of
the degree of crystallization, disarray of the fibril structure,
and softening of the whole fiber, and a decrease in the difference
in structure between the crystal/amorphous parts which becomes a
trigger of the destruction improves the abrasion resistance.
Because the abrasion resistance more improves with lower
.DELTA.Hm.sub.1, .DELTA.Hm.sub.1 is preferably 5.0 J/g or less. The
lower limit of .DELTA.Hm.sub.1 is not particularly restricted, and
in order to achieve high strength and elastic modulus,
.DELTA.Hm.sub.1 is preferably 0.5 J/g or more.
[0073] When the liquid crystalline polyester fibers are subjected
to solid-phase polymerization, the molecular weight increases, and
the strength, elongation, elastic modulus and thermal resistance
increase, and at the same time, the degree of crystallization also
increases, and the .DELTA.Hm.sub.1 increases. If the degree of
crystallization increases, the strength, elongation, elastic
modulus and thermal resistance further increase, but the difference
in structure between the crystal part and the amorphous part
becomes remarkable, the interface therebetween is liable to be
destroyed, and the abrasion resistance decreases. In contrast to
this, it is preferred, from the viewpoint of improving the abrasion
resistance, to have a low degree of crystallization such as that of
a liquid crystalline polyester fiber which has not been subjected
to the solid-phase polymerization, that is a low .DELTA.Hm.sub.1,
concurrently with maintaining the high strength, elastic modulus
and thermal resistance by having a high molecular weight that is
one of the features of the fiber which has been subjected to the
solid-phase polymerization.
[0074] Such a fiber structure can be attained, for example, by
subjecting a liquid crystalline polyester fiber obtained by the
solid-phase polymerization, which is described later, to a heat
treatment at a temperature of Tm.sub.1 of the liquid crystalline
polyester fiber +10.degree. C. or higher.
[0075] Tm.sub.1, half width of peak at Tm.sub.1, .DELTA.Hm.sub.1 of
the liquid crystalline polyester fiber, which are described above,
refers to values obtained by a method described in Section E in
Examples.
[0076] It is preferred that a finishing oil agent be applied to the
liquid crystalline polyester fiber of the present invention for
improving abrasion resistance and process passability by improved
surface smoothness. The oil adhesion rate of finishing oil agent is
preferably 0.1 wt % or more based on the fiber weight. The oil
adhesion rate that is referred in the present invention refers to a
value determined by a method described in Section D in Examples.
Because a higher oil content leads to more effects, it is
preferably 0.5 wt % or more. Yet, if the oil content is too high,
yarn breakage occurs because adhesion force between fibers
increases and neighboring yarns gather together to falsely adhere,
and process pollution takes place by accumulation of excessive oil
agents on guides or tension providers by scratch in steps, which
increases the number of times of machine stopping for a cleaning
step and causes problems such as weavability defect. Therefore, it
is preferably 3.0 wt % or less and 2.0 wt % or less.
[0077] As the type of finishing oil agent, a finishing oil agent
for common polyester monofilament can be employed. In order to
avoid decrease in process passability by scum generation in a
weaving step, the finishing oil agent preferably does not contain
particulates.
[0078] A method of producing of the liquid crystalline polyester
fiber the present invention will now be described in detail
below.
[0079] The melting point of the liquid crystalline polyester
polymer used in the present invention is preferably 200 to
380.degree. C. in order to widen the temperature range where the
melt spinning is feasible, and more preferably 250 to 360.degree.
C. The melting point of the liquid crystalline polyester polymer
refers to a value measured by a method described in Section E in
Examples.
[0080] The weight average molecular weight of the liquid
crystalline polyester used in the present invention determined in
terms of a polystyrene-equivalent weight average molecular weight
(hereinafter, referred to as "molecular weight") is preferably
30,000 or more. By having a molecular weight of 30,000 or more, an
adequate viscosity can be provided at a spinning temperature and
the yarn formation property can be improved. With a higher
molecular weight, the strength, elongation and elastic modulus of
the fiber to be obtained increase. If the molecular weight is too
high, the viscosity becomes high and the flowability deteriorates,
and ultimately it becomes impossible to flow, and therefore the
molecular weight is preferably less than 250,000, and more
preferably less than 200,000. The weight average molecular weight
determined in terms of a polystyrene-equivalent weight average
molecular weight that is referred here means a value measured by a
method described in Section F in Examples.
[0081] The liquid crystalline polyester of the present invention is
preferably dried up before being subjected to melt spinning, from
the viewpoint of suppressing foaming caused by water mixture and of
enhancing the yarn formation property. Vacuum drying is more
preferably carried out because the monomer remaining in the liquid
crystalline polyester can be removed and thereby the yarn formation
property is further enhanced. As for drying conditions, the vacuum
drying is usually carried out at 100 to 200.degree. C. for 8 to 24
hours.
[0082] In the melt spinning, although a known method can be used
for melt extrusion of liquid crystalline polyester, in order to
prevent an ordered structure from being produced at the time of
polymerization, an extruder-type extruding machine is preferably
used. The extruded polymer is metered by a known metering device
such as a gear pump through flow path, and after passing through a
filter for removing extraneous materials, it is introduced into a
die. At that time, the temperature (spinning temperature) from the
polymer flow path to the die is preferably controlled at a
temperature of the melting point of the liquid crystalline
polyester or higher, and more preferably at a temperature of the
melting point of the liquid crystalline polyester +10.degree. C. or
higher. Yet, if the spinning temperature is too high, the viscosity
of the liquid crystalline polyester increases to deteriorate
fluidity and yarn formation property, and therefore it is
preferably 500.degree. C. or lower, and more preferably 400.degree.
C. or lower. It is also possible to independently adjust each of
the temperatures from the polymer flow path to the die. In this
case, the discharge can be stabilized by controlling the
temperature of a portion near the die higher than the temperature
of an upstream portion thereof.
[0083] With regard to the discharge, it is preferred to make the
hole diameter of the die smaller and to make the land length (a
length of a straight part having the same length of the hole
diameter of the die) longer, from the viewpoint of enhancing yarn
formation property and uniformity of fineness. However, if the hole
diameter is excessively small, because a clogging of a hole is
liable to occur, the diameter is preferably 0.05 mm or more, and
0.50 mm or less, and is more preferably 0.10 mm or more, and 0.30
mm or less. If the land length is excessively long, the pressure
loss becomes high and thus L/D defined as a quotient calculated by
dividing the land length by the hole diameter is preferably 1.0 or
more and 3.0 or less, and is more preferably 2.0 or more and 2.5 or
less.
[0084] Further, the number of holes in the die can be selected as
appropriate in accordance with applications, and, in order to keep
the uniformity, the number of holes in a single die is preferably
1,000 holes or less, and is more preferably 500 holes or less. The
introduction hole positioned immediately above the die hole is
preferably a straight hole, from the point of preventing increase
of the pressure loss. A connecting portion between the introduction
hole and the die hole is preferably formed in a taper shape from
the viewpoint of suppressing an abnormal staying. Further, the
lower limit of the number of holes may be one hole.
[0085] The polymer discharged from the die holes passes through
heat insulating and cooling regions and is solidified, and is
thereafter drawn up by a roller (godet roller) rotating at a
constant speed. If the heat insulating region is excessively long,
because the yarn formation property deteriorates, it is preferably
200 mm or less from the die surface, and is more preferably 100 mm
or less. In the heat insulating region, it is possible for the
atmosphere temperature to be increased by using a heating means,
and a temperature range thereof is preferably 100.degree. C. or
higher and 500.degree. C. or lower, and more preferably 200.degree.
C. or higher and 400.degree. C. or lower. Although inert gas, air,
steam or the like can be used for the cooling, it is preferred to
use an air flow blown in a parallel or circular pattern, from the
viewpoint of lowering the environmental load.
[0086] The draw speed is preferably 50 m/min or more for improving
the productivity and decreasing the single-yarn fineness, and is
more preferably 500 m/min or more. Because the liquid crystalline
polyester that was exemplified as a desirable example in the
present invention has a suitable yarn-drawing property at a
spinning temperature, the draw speed can be set high. The upper
limit thereof is not restricted and it is about 2,000 m/min from
the viewpoint of the yarn-drawing property.
[0087] The spinning draft defined as a quotient calculated by
dividing the discharge linear speed by the draw speed is preferably
1 or more and 500 or less, and is more preferably 10 or more and
100 or less for enhancing the yarn formation property and
uniformity of fineness.
[0088] In the melt spinning, it is preferred to add an oil agent
between the cooling to solidify the polymer and the take-up, from
the viewpoint of improving the handling property of the fiber.
Although a known oil agent can be used, it is preferred to use a
common spinning oil agent or a mixed agent of the inorganic
particles (A) and phosphate-based compound (B) described later,
from a viewpoint of improving the unwinding when a fiber that is
obtained by the melt spinning (hereinafter called original yarn of
spinning) is unwound at the rewinding process before the
solid-phase polymerization.
[0089] Although the take-up can be carried out by using a known
winder and forming a package such as a pirn, a cheese, or a cone, a
pirn winding in which a roller does not come into contact with a
package surface at the time of the take-up is preferred, from the
viewpoint of not giving a friction to the fibers and not
fibrillating it.
[0090] The single-fiber fineness of the fiber obtained by carrying
out melt spinning (before solid-phase polymerization) is preferably
18.0 dtex or less. The single-fiber fineness that is referred here
is a value determined by a method described in Section B in
Examples. By making the fiber thinner at a single-fiber fineness of
18.0 dtex or less, the molecular weight of the polymer is easy to
increase when polymerized in solid phase at fibrous state, and the
strength, elongation and elastic modulus improved. Further, because
the surface area increase, the fiber has the feature of being
capable of increasing the adhesion amount of inorganic particles
(A) and a phosphate-based compound (B). The single-fiber fineness
is more preferably 10.0 dtex or less, and still more preferably 7.0
dtex or less. Although the lower limit of the single-fiber fineness
is not particularly restricted, a lower limit that can be achieved
by a method of production described later is about 1.0 dtex.
[0091] The number of filaments and the total fineness of a fiber
obtained by carrying out melt spinning (before solid-phase
polymerization) can be freely selected. In the case of a mesh woven
fabric, for making a fiber product thinner or lighter in weight,
the number of filaments is preferably 50 or less, more preferably
20 or less. In particular, because a monofilament whose number of
filaments is one is for a field in which suppression of scum
generation and stability of running tension are required, the
liquid crystalline polyester fiber obtained by the method of
production of the present invention can be in particular used
suitably.
[0092] Besides, the liquid crystalline polyester fiber obtained by
the method of production of the present invention can be used in
applications of multifilament, such as tension members, various
stiffeners, fishing nets, ropes or the like. In this case, the
total fineness of the fiber obtained by carrying out melt spinning,
that is, the fiber to be subjected to solid-phase polymerization
can be selected. Because if the total fineness is excessively
small, fusion bonding between yarns is easy to occur at the time of
solid-phase polymerization, which cause defects upon unwinding and
deteriorates process passability, the total fineness is preferably
5 dtex or more, more preferably 20 dtex or more and still more
preferably 100 dtex or more. The total fineness that is referred
here is a value determined by a method described in Section B in
Examples. Further, if the total fineness is excessively large,
difference is formed between the inside and outside of the yarn at
the time of solid-phase polymerization, which readily causes single
yarn breakage and deteriorates process passability. Therefore, the
total fineness is preferably 10,000 dtex or less, more preferably
2,000 dtex or less. Furthermore, in cases where the fiber is used
in applications of multifilament, the number of single yarns
contained in a yarn, that is, the number of filaments is preferably
2 or more, more preferably 5 or more, still more preferably 50 or
more, and in particular preferably 100 or more. By making the
number of filaments large, the total fineness can be made large
even when the single fiber fineness is small. The fiber has both
flexibility and high tenacity (product of strength and total
fineness) of the yarn and thereby is excellent in process
passability. Because an excessively large number of filaments lead
to poor ease of handling, the upper limit thereof is about
5,000.
[0093] In order to prevent yarn breakage in a rewinding step before
solid-phase polymerization which is the next step and to improve
process passability, the strength of fiber obtained by carrying out
melt spinning is preferably 3.0 cN/dtex or more, and more
preferably 5.0 cN/dtex or more. The upper limit of the strength is
about 10 cN/dtex in the present invention.
[0094] In order to prevent yarn breakage in a rewinding step before
solid-phase polymerization which is the next step and to improve
process passability, the elongation of fiber obtained by carrying
out melt spinning is preferably 0.5% or more, and more preferably
1.0% or more. The upper limit of the elongation is 5.0% in the
present invention.
[0095] In order to prevent yarn breakage in a rewinding step before
solid-phase polymerization which is the next step and to improve
process passability, the elastic modulus of fiber obtained by
carrying out melt spinning is preferably 300 cN/dtex or more, and
more preferably 500 cN/dtex or more. The upper limit of the elastic
modulus is 800 cN/dtex in the present invention.
[0096] The strength, elongation, and elastic modulus that are
referred in the present invention are values determined by a method
described in Section C in Examples.
[0097] In the present invention, the liquid crystalline polyester
fiber obtained by carrying out melt spinning is subjected to
solid-phase polymerization after applying inorganic particles (A)
and a phosphate-based compound (B). The application of the
inorganic particles (A) and phosphate-based compound (B) produce
effects of suppressing fusion bonding between fibers generated in
the solid-phase polymerization process. In addition, as the
components undergo thermal denaturation in the solid-phase
polymerization step by mechanisms described later, a liquid
crystalline polyester fiber in which these (A) and (B) components
are readily remove from the fiber in a subsequent cleaning step is
obtained. Further, the fiber obtained by carrying out the cleaning
has a small amount of residues of the solid-phase polymerization
oil agent on the fiber and thus generation of scum and fluctuation
of running tension are suppressed, thereby leading to good
weavability.
[0098] The inorganic particles (A) in the present invention include
known inorganic particles. Examples thereof include minerals, metal
hydroxides such as magnesium hydroxide, metal oxides such as silica
or alumina, carbonates such as calcium carbonate or barium
carbonate, sulfates such as calcium sulfate or barium sulfate, and
silicates. Besides, carbon black and the like are included.
Application of such inorganic particles with high thermal
resistance onto the fiber reduces a contact area between single
yarns and allows fusion bonding generated at the time of the
solid-phase polymerization to be avoided.
[0099] The inorganic particles (A) are preferably easy to be
handled in the light of the application step and easy to disperse
in water from the viewpoint of reducing environmental load and are
desirably inactive under conditions for solid-phase polymerization.
From these viewpoints, it is preferred to use silica or silicates.
In the case of silicates, phyllosilicates having layered structure
is in particular preferred. Examples of phyllosilicates include
kaolinite, halloysite, serpentine, garnierite, smectite group,
pyrophyllite, talc, and mica. Of theses, it is most preferred to
use talc or mica in the light of a fact that talc or mica is
readily available.
[0100] Further, the median diameter (D50) of the inorganic particle
(A) is preferably 10 .mu.m or less. That is because, with D50 being
10 .mu.m or less, a probability of inorganic of the particle (A)
being retained between fibers and an effect of suppressing fusion
bonding becomes prominent. For the same reason, D50 is more
preferably 5 .mu.m or less. Further, the lower limit of D50 is
preferably 0.01 .mu.m or more in terms of cost and in the light of
cleaning properties in the cleaning step after the solid-phase
polymerization. The median diameter (D50) that is referred here is
a value measured by a method described in Section G in
Examples.
[0101] Further, as the phosphate-based compound (B) of the present
invention, a compound represented by (1) to (3) in the following
chemical formula can be used.
##STR00004##
[0102] wherein, R.sub.1 and R.sub.2 represents a hydrocarbon group;
M.sub.1 represents alkali metal; and M.sub.2 represents a group
selected from alkali metal, hydrogen atom, hydrocarbon group, and
hydrocarbon group containing oxygen atoms.
[0103] Note that n represents an integer of 1 or more. The upper
limit of n is preferably 100 or less from the viewpoint of
suppressing thermal decomposition, and is more preferably 10 or
less.
[0104] R.sub.1 preferably does not contain phenyl groups in the
structure thereof in consideration of gas generated by thermal
decomposition at the time of solid-phase polymerization and from
the viewpoint of reducing environmental load, and is more
preferably composed of alkyl groups. The number of carbon atoms in
R.sub.1 is preferably 2 or more from the viewpoint of affinity to
the fiber surface, and preferably 20 or less from the viewpoint of
limiting weight reducing rate by decomposition of organic
components associated with the solid-phase polymerization and of
preventing carbides produced by decomposition at the time of the
solid-phase polymerization from remaining on the fiber surface.
[0105] Further, R.sub.2 is a hydrocarbon having 5 carbon atoms or
less from the viewpoint of solubility in water, and more preferably
a hydrocarbon having 2 or 3 carbon atoms.
[0106] M.sub.1 is preferably sodium or potassium from the viewpoint
of production cost.
[0107] Use of the phosphate-based compound (B) in conjunction with
the inorganic particle (A) not only enhances the dispersion
property of the inorganic particle (A), enables uniform application
onto the fiber, produce an excellent effect of suppressing fusion
bonding, but also can suppress firm adhesion of the inorganic
particle (A) onto the fiber surface. Therefore, the amount of the
inorganic particle (A) remaining on the fiber after the cleaning
decreases and an effect of suppressing scum generation in a
subsequent processing step is developed. In addition, the present
inventors have intensively studied to find out that a condensation
salt of phosphates is formed by dehydration reaction and
decomposition of organic components contained in the
phosphate-based compound (B) under conditions of the solid-phase
polymerization and the phosphate-based compound (B) can be readily
removed using water in the cleaning step after the solid-phase
polymerization due to this formation of the condensation salt.
Meanwhile, it was confirmed that, when the phosphate-based compound
(B) was solely applied, because of deliquescent property of the
condensation salt, the phosphates on the fiber surface showed
moisture absorption and deliquescence to become viscous even in
common storage conditions of fibers, thereby deteriorating the
cleaning property. That is, they have found that an excellent
cleaning property is not developed until the inorganic particle (A)
and phosphate-based compound (B) are combined to use. As mechanisms
whereby this excellent cleaning property is developed, it is
presumed that the use of the inorganic particle (A) in combination
prevents the natural moisture absorption and deliquescence of the
condensation salt of the phosphate-based compound (B) because the
inorganic particle (A) has moisture absorbency, and the
condensation salt of the phosphate-based compound (B) absorbs water
to swell only when passing in water and peels to fall off from the
fiber surface in a form of layers together with the inorganic
particle (A).
[0108] For uniform application of the inorganic particle (A) and
phosphate-based compound (B) while controlling the adhesion amount
thereof to be appropriate, it is preferred to use a mixed oil agent
with the inorganic particle (A) being added for a dilution solution
of the phosphate-based compound (B). From the viewpoint of safety,
it is preferred to use water is preferably used as a solution for
dilution. From the viewpoint of suppressing fusion bonding, the
concentration of the inorganic particle (A) in the dilution
solution is preferably 0.01 wt % or more and more preferably 0.1 wt
% or more. The upper limit thereof is preferably 10 wt % or less
from the viewpoint of uniform dispersion and more preferably 5 wt %
or less. Further, the concentration of the phosphate-based compound
(B) is preferably 0.1 wt % or more from the viewpoint of uniform
dispersion of the inorganic particle (A) and more preferably 1.0 wt
% or more. The upper limit of the concentration of the
phosphate-based compound (B) is not particularly restricted, and,
for the purpose of avoiding excessive adhesion by increase in the
viscosity of the mixed oil agent and spotty adhesion by increase in
temperature dependency of the viscosity, is preferably 50 wt % or
less and more preferably 30 wt % or less.
[0109] Further, as a method of applying the inorganic particle (A)
and phosphate-based compound (B) to the fiber, the application may
be carried out between melt spinning and winding. Yet, in order to
enhance an adhesion efficiency, it is preferred that the
application be carried out to yarns while winding back the yarns
taken up by melt spinning, or a small amount be adhered in melt
spinning, after which additional application is carried out while
winding back the yarns taken up.
[0110] Although the method for oil adhesion may be a method for
supplying oil by a guide, in order to apply oil to uniformly adhere
to a fiber with a small total fineness such as a monofilament,
adhesion by a kiss roller (oiling roller) made of a metal or a
ceramic is preferred. In cases where the fiber is in a state of a
hank or a tow, it can be immersed into an oil mixture agent for
application.
[0111] When the adhesion rate of the inorganic particle (A) to the
fiber is designated as (a) wt %, and the adhesion rate of the
phosphate-based compound (B) is designated as (b) wt %, it is
preferred that both satisfy the following conditions.
30.gtoreq.a+b.gtoreq.2.0 Condition 1
a.gtoreq.0.05 Condition 2
b/a.gtoreq.1 Condition 3
[0112] In the above condition 1, because the higher the oil
adhesion rate of solid-phase polymerization oil agent (a+b) the
more fusion bonding can be suppressed, it is preferably 2.0 wt % or
more. On the other hand, because excessive oil agent makes the
fiber sticky to deteriorate ease of handing, it is preferably 30 wt
% or less. It is more preferred to be 4.0 wt % or more and 20 wt %
or less. The oil adhesion rate (a+b) of the solid-phase
polymerization oil agent to the fiber refers to a value of an oil
adhesion rate determined for a fiber after the application of the
solid-phase polymerization oil agent by a method described in
Section D in Examples.
[0113] Here, in cases where an oil agent other than the solid-phase
polymerization oil agent is applied to the fiber before the
solid-phase polymerization oil agent is applied on fiber, an oil
adhesion rate D.sub.1 is determined for a fiber before the
application of the solid-phase polymerization oil agent by a method
described in Section D in Examples, an oil adhesion rate D.sub.2 is
determined for a fiber after the application of the solid-phase
polymerization oil agent by a method described in Section D in
Examples, and a difference between these D.sub.2-D.sub.1 is
designated as the oil adhesion rate (a+b) of the solid-phase
polymerization oil agent.
[0114] In the condition 2, by setting the adhesion rate of the
inorganic particle (A) (a) to 0.05 wt % or more, an effect of
suppressing fusion bonding by the inorganic particle become
prominent. The upper limit of the adhesion rate (a) is, as rough
indication, 5 wt % or less from the viewpoint of uniform
adhesion.
[0115] In the condition 3, the adhesion rate of phosphate-based
compound (B) (b) is preferably higher than the adhesion rate of the
inorganic particle (A) (a) because an excellent cleaning property
of the phosphate-based compound (B), which is ascribed to
condensation salt formation at time of the solid-phase
polymerization, becomes more prominent and also from the viewpoint
of suppressing firm adhesion between the inorganic particle (A) and
fiber.
[0116] The adhesion rate of the inorganic particle (A) (a) and
adhesion rate of phosphate-based compound (B) (b) that are referred
here means values calculated by the equation below.
Adhesion rate of the inorganic particle (A)
(a)=(a+b).times.Ca/(Ca+Cb)
Adhesion rate of phosphate-based compound (B)
(b)=(a+b).times.Cb/(Ca+Cb)
[0117] wherein, Ca refers to the concentration of the inorganic
particle (A) in the solid-phase polymerization oil agent (wt %) and
Cb refers to the concentration of the phosphate-based compound (B)
in the solid-phase polymerization oil agent (wt %).
[0118] In the present invention, the solid-phase polymerization is
carried out after applying the inorganic particles (A) and
phosphate-based compound (B). By carrying out the solid-phase
polymerization, the molecular weight increases and in turn the
strength, elastic modulus and elongation thereby increase. The
solid-phase polymerization can be processed at a state of a hank or
a tow (for example, carried out on a metal net or the like), or can
be processed at a yarn state continuously between rollers, and it
is preferably carried out at a package state, where the fibers are
taken up into a core material, from the viewpoint of simplifying
facilities and improving productivity.
[0119] In case where the solid phase polymerization is carried out
at a package state, the winding density is preferably 0.01 g/cc or
more for preventing of collapses of the winding form; and the
winding density is preferably 1.00 g/cc or less and more preferably
0.80 g/cc for avoiding fusion bonding. Here, the winding density is
a value calculated by Wf/Vf from an occupation volume of the
package Vf (cc) which is determined from the outer dimension of the
package and the dimension of the bobbin that becomes a core
material, and a weight of fiber Wf (g). Further, because the
winding form of the package collapses if the winding density is
excessively small, the winding density is preferably 0.03 g/cc or
more. Note that the occupation volume Vf is a value determined by
actually measuring the outer dimension of the package, and the Wf
is a value calculated from the fiber fineness and the winding
length.
[0120] Formation by taking up in melt spinning of the package with
such a small winding density is desirable because the productivity
for apparatus and the efficiency of production can be improved, and
on the other hand, formation by rewinding from the package wound in
melt spinning is preferable because the winding tension can be made
small and the winding density can be made smaller. In the
rewinding, the winding density can be made smaller as the winding
tension is made smaller, the winding tension is preferably 0.30
cN/dtex or less and more preferably 0.20 cN/dtex or less. Although
the lower limit is not particularly restricted, a lower limit that
can be achieved in the present invention is about 0.01 cN/dtex.
[0121] For lowering the winding density, the rewinding speed is
preferably set at 500 m/min or less, and more preferably 400 m/min
or less. On the other hand, a higher rewinding speed is
advantageous from the viewpoint of productivity, and it is
preferably set at 50 m/min or more, and, in particular, 100 m/min
or more.
[0122] In order to form a stable package even in a low-tension, the
form of winding is preferably a taper-end winding provided with
tapers at both ends. In this case, the taper angle is preferably
60.degree. or less, and more preferably 45.degree. or less.
Further, in cases where the taper angle is small, the fiber package
cannot be made larger; and in cases where a long fiber is required,
the taper angle is preferably 1.degree. or more, and more
preferably 5.degree. or more. Note that the taper angle that is
referred in the present invention is defined by the following
equation.
.theta. = tan - 1 ( 2 d li - lo ) ##EQU00001##
.theta.: taper angle (.degree.); d: winding thickness (mm);
l.sub.i: stroke of the innermost layer (mm); l.sub.o: stroke of the
outermost layer (mm)
[0123] Further, although a smaller number of winding in the
formation of package is advantageous for avoiding fusion bonding
because the contact area between fibers is smaller, it is possible
to decrease a traverse failure or a swelling of package, and to
make a package form better as the number of winding becomes higher.
From these points, the number of winding is preferably 2 or more
and 20 or less, and more preferably 5 or more and 15 or less. The
number of winding that is referred here is the number of times of
rotation of a spindle during half reciprocation of a traverse, and
defined as a product of a time for the half reciprocation of a
traverse (minute) and a rotational speed of a spindle (rpm). The
higher number of winding indicates the smaller traverse angle.
[0124] The bobbin used for forming the fiber package may be any
type bobbin as long as it has a cylindrical shape, and it is
attached to a winder when wound back as the fiber package, and the
fibers are taken up to form a package by rotating it. In a
solid-phase polymerization, although the fiber package can be
treated integrally with the bobbin, the treatment can also be
carried out at a condition where only the bobbin is taken out from
the fiber package. In cases where the treatment is carried out at a
condition where the fibers are wound on the bobbin, the bobbin
needs to resist the temperature of the solid-phase polymerization,
and therefore, it is preferably made from a metal such as aluminum,
brass, iron or stainless steel. Further, in this case, it is
preferred that many holes are opened on the bobbin because a
by-product of polymerization can be quickly removed and the
solid-phase polymerization can be carried out efficiently. Further,
in cases where the treatment is carried out at a condition where
the bobbin is taken out from the fiber package, it is preferred to
attach an outer skin onto the outer layer of the bobbin. Further,
in any of both cases, it is preferred that a cushion material be
wound around the outer layer of the bobbin and that the liquid
crystalline polyester melt spun fibers be taken up onto it, from
the viewpoint of preventing fusion bonding between fibers in the
innermost layer of the package and the outer layer of the bobbin.
The kind of the cushion material is preferably a felt made of an
organic fiber or metal fiber, and the thickness thereof is
preferably 0.1 mm or more and 20 mm or less. The above-mentioned
outer skin can also be substituted with the cushion material.
[0125] The fiber weight of the fiber package may be any weight, and
a preferred range is 0.1 kg or more and 20 kg or less in light of
productivity. As for the yarn length, a preferred range is 10,000 m
or more and 2,000,000 m or less.
[0126] Although it is possible to carry out solid-phase
polymerization in an inert gas atmosphere, in an activated gas
atmosphere containing oxygen such as air, or under a reduced
pressure condition, it is preferably carried out in a nitrogen
atmosphere from the viewpoint of simplifying facilities and
preventing oxidation of fibers or core materials. In this case, the
atmosphere for the solid-phase polymerization is preferably a
low-humidity gas having a dew point of -40.degree. C. or lower.
[0127] The maximum temperature of solid-phase polymerization
temperature is preferably Tm.sub.1-60.degree. C., where Tm.sub.1
(.degree. C.) is defined as an endothermic peak temperature of the
liquid crystalline polyester fibers to be subjected to solid-phase
polymerization. Such a high temperature around the melting point
makes it possible for the solid-phase polymerization to progress
immediately, thereby improving the fiber strength. Tm.sub.1 that is
referred here is generally the melting point of a liquid
crystalline polyester fiber, and it refers a value obtained by a
measurement method described in Section E in Example in the present
invention. The maximum temperature is preferably less than Tm.sub.1
(.degree. C.) for preventing fusion bonding. Further, it is more
preferred that the solid-phase polymerization temperature be
enhanced gradually or continuously as time goes by, which can
prevent the fusion bonding and concurrently improve the time
efficiency of the solid-phase polymerization. In this case, because
the melting point of the liquid crystalline polyester fibers
increases as the solid-phase polymerization progressed, the
solid-phase polymerization temperature can be increased to around
Tm.sub.1 of the liquid crystalline polyester fibers before the
solid-phase polymerization +100.degree. C. However, also in this
case, the maximum temperature during solid-phase polymerization is
preferably Tm.sub.1 of the fibers which have been polymerized in
solid phase -60 (.degree. C.) or more and less than Tm.sub.1
(.degree. C.), from a viewpoint of enhancement of the solid-phase
polymerization speed and prevention of the fusion bonding.
[0128] With respect to the time for solid phase polymerization, in
order to sufficiently increase the melting point of the fiber, that
is, the strength, elastic modulus and elongation, the time at a
maximum reaching temperature is preferably 5 hours or more, and
more preferably 10 hours or more. On the other hand, because
effects of increased strength, elastic modulus and elongation is
saturated as the time passes, in order to improve the productivity,
the time for solid phase polymerization is preferably about 50 or
less.
[0129] In the liquid crystalline polyester fiber obtained by the
method of production of the present invention, the solid-phase
polymerization oil agent can be readily removed by cleaning.
Because a fiber after the cleaning does not have gelled products or
solids derived from organic components on the fiber, an amount of
deposit generated is low in the weaving step and running tension
fluctuation is drastically improved. Therefore, process stability
and product yield in the weaving can be drastically improved. That
is, the liquid crystalline polyester fiber obtained by the method
of production of the present invention has a small amount of
deposit (scum) in the weaving step, exhibits small fluctuation of
running tension and is excellent in process passability. Thus, it
is suitable as fiber capable of providing a liquid crystalline
polyester fiber with drastically improved product yield of woven
fabric. The liquid crystalline polyester fiber that, as seen above,
has a small amount of deposit (scum) in the weaving step, exhibits
small fluctuation of running tension and is excellent in process
passability can be in particular suitably used in mesh woven
fabrics like filters for carrying out weaving or screen gauzes.
[0130] Further, the liquid crystalline polyester fiber obtained by
the method of production of the present invention can be expanded
to applications other than mesh woven fabrics like filters for
carrying out weaving or screen gauzes. Although it depends on the
type of the applications, the liquid crystalline polyester fiber
obtained by the method of production of the present invention can
be utilized without carrying out the cleaning. For example, a fiber
obtained in a processing step of multifilament application in the
present invention is excellent in processability because it is
coated with salts and particles which are powders on the fiber
surface, which decreases running resistance by an action of powder
mold releasing and can prevent fibrillation by scratch of the
fiber, thereby enhancing running stability. In addition, that is
because both can be readily cleaned and removed by water and thus a
state of adhered substances being substantially absence on the
fiber surface by cleaning with water when the fiber is made to a
product is generated, which enhances adhesion property with
chemical solution or resins.
[0131] As mentioned above, the liquid crystalline polyester fiber
obtained by the method of production or the present invention can
be widely used in the field such as materials for general industry,
materials for civil engineering and construction, use in sports,
clothing for protection, materials for reinforcement of rubbers,
electric materials (in particular, as tension members), acoustic
materials, general clothing, or the like. Examples of effective
applications include screen gauzes, filters, ropes, nets, fishing
nets, computer ribbons, base fabrics for printed boards, canvases
for paper machines, air bags, airships, base fabrics for domes,
rider suits, fishing lines, various lines (lines for yachts,
paragliders, balloons, kite yarns), blind cords, support cords for
screens, various cords in automobiles or air planes, and power
transmission cords for electric equipments or robots. Examples of
particularly effective applications include monofilaments used in
woven fabrics for industrial materials. Of these, it can be
suitably used as screen gauzes for printing or mesh woven fabrics
for filters that strongly require high strength, high elastic
modulus and higher fineness, and also require suppression of
tension fluctuation by generation of deposits in the steps for
improving the weavability and quality of fabric.
[0132] In the present invention, from the viewpoint of improving
process passability and product yield in the weaving step, it is
preferred that cleaning be carried out after carrying out the
solid-phase polymerization. Removal of the solid-phase
polymerization oil agent for fusion bonding prevention by carrying
out the cleaning allows deterioration of process passability due to
accumulation of the solid-phase polymerization oil agent on a guide
or the like in subsequent steps including, for example, the weaving
step, generation of defects due to contamination of the accumulated
substance into a product, or the like to be suppressed.
[0133] Examples of a method of cleaning include a method of wiping
on the fiber surface bay a cloth of paper. Yet, because
fibrillation takes place when mechanical load is applied to the
solid-phase polymerization yarn, a method of immersing the fiber in
a liquid in which the solid-phase polymerization oil agent can be
dissolved or dispersed. In addition to the method of immersing in
the liquid, a method of blowing off using a fluid is more preferred
because the solid-phase polymerization oil agent swollen by the
liquid can be efficiently removed.
[0134] The liquid used in the cleaning is preferably water for
reducing environmental load. The higher the temperature of the
liquid is, the higher the removal efficiency can be and the
temperature of the liquid is preferably 30.degree. C. or higher and
more preferably 40.degree. C. or higher. Yet, because the liquid
significantly evaporate when the temperature is too high, it is
preferably the boiling point of the liquid -20.degree. C. or lower
and more preferably the boiling point -30.degree. C. or lower.
[0135] It is preferred to add a surfactant to the liquid used in
the cleaning from the viewpoint improving cleaning efficiency. The
amount of surfactant added is preferably 0.01 to 1 wt % for
enhancing the removal efficiency and reducing the environmental
load and more preferably 0.1 to 0.5 wt %.
[0136] Further, for enhancing the cleaning efficiency, it is
preferred to impart vibration or liquid current to the liquid used
in the cleaning. In this instance, although there are methods such
as ultrasonic vibration of the liquid, it is preferred to impart
liquid current from the viewpoint of simplifying facilities and
saving energy. Examples of methods of imparting liquid current
include a method of stirring inside a liquid bath, and a method of
imparting liquid current using a nozzle. It is preferred to impart
liquid current using a nozzle because it can be readily carried out
by supplying the liquid current circulating in the liquid bath
using the nozzle.
[0137] A degree of removal of the solid-phase polymerization oil
agent by the cleaning is adjusted as appropriate in accordance with
purpose. From the viewpoint of improving process passability of
fibers in a higher-order processing step and weaving step and of
improving the quality of woven fabrics, the oil adhesion rate of
solid-phase polymerization oil agent remaining on the fiber after
the cleaning is preferably 2.0 wt % or less, more preferably 1.0 wt
% or less, and still more preferably 0.5 wt % or less. The adhesion
rate of solid-phase polymerization oil agent refers to a value
determined for a fiber wound back immediately after the cleaning
step by a method described Section D in Examples.
[0138] In the cleaning, the fiber may be immersed in liquid at a
hank, tow or package condition to increase an amount of throughput
per unit time. The fiber is preferably immersed in the liquid while
being run continuously in order to achieve uniform removal along a
fiber lengthwise direction. A method of immersing the fiber
continuously may be a method of introducing the fiber into a bath
using a guide or the like. It is preferred that slits be provided
at both sides of the bath so that the fiber can pass through those
slits in the bath, without providing any yarn path guide inside the
bath, in order to suppress the fibrillation of the solid-phase
polymerization fiber derived from the contact resistance to the
guide.
[0139] In cases where the solid-phase polymerized yarn in a form of
package is forced to run continuously, the fiber is unwound. In
order to suppress fibrillation at the time of delamination of a
little fusion bonding, it is preferred to unwind the yarn in a
direction (fiber rounding direction) perpendicular to a rotation
axis by so-called lateral unwinding, as rotating the package which
has been polymerized in a solid phase.
[0140] Examples of such a method of unwinding include a method of
positively driving at a constant rotation speed using a motor or
the like, a method of speed-regulating unwinding with the rotation
speed being controlled using a dancer roller and a method of
subjecting the solid-phase polymerized package to a free roll and
unwinding as pulling the fiber by a speed-regulating roller.
Further, a method of immersing the liquid crystalline ester fiber
in a liquid in a form of package and unwinding as is a preferred
mode because oil contents can be efficiently removed.
[0141] The fluid used in the case of blowing off using a fluid is
preferably air or water. In particular, in cases where air is used
for the fluid, it can be expected to exert an effect of drying the
surface of the liquid crystalline polyester fiber, which prevents
accumulation of pollution in subsequent steps, and potentially
improve yield, and thus air is a preferred mode.
[0142] Further, because liquid used in the cleaning remains on the
surface of the liquid crystalline polyester fiber after the
cleaning, rinsing is a preferred mode as well. If the liquid used
in the cleaning remains on the surface of the liquid crystalline
polyester fiber, it ultimately dries and becomes an extraneous
material on the yarn surface. The rinsing allows the surface of the
liquid crystalline polyester fiber to be more uniform and can
suppress fluctuation of unwinding tension ascribed to accumulation
of foreign matters in subsequent steps.
[0143] The fluid used in the rinsing is preferably water. The
rinsing is carried out for the purpose of removing cleaning
solution components adhered onto the surface of the liquid
crystalline polyester fiber. Thus, by using water which is capable
of dissolving such components, the cleaning can be efficiently
carried out. Further, for the purpose of increase the solubility of
those components, warming water is a preferred mode as well.
Because the solubility increases as the temperature increases and
the efficiency of rinsing is expected to go up, the upper limit of
the warming temperature is not particularly restricted. The warming
temperature may be 80.degree. C. as a rough target in the light of
controlling energy consumption required for the warming to reduce
energy cost and of loss by evaporation.
[0144] Addition of combinational removal of moisture remaining on
the surface of the liquid crystalline polyester fiber by the
blowing off after carrying out the rinsing makes the mode more
preferred.
[0145] Further, it is preferred to apply a finishing oil agent form
the viewpoint of improving process passability in subsequent steps
after the cleaning. As the finishing oil agent, a finishing oil
agent that is commonly used for polyester fibers can be preferably
employed. It is more preferred not to contain particles from the
viewpoint of suppressing fluctuation of running tension caused by
dropping off during the step.
[0146] The oil adhesion rate of the finishing oil agent is
preferably 0.1 wt % or more for the fiber in order to exert effects
such as lubricity by finishing oil agent, and is preferably 3.0% or
less for the purpose of preventing pollution by excessive addition
in post processing steps. The oil adhesion rate of the finishing
oil agent that is referred here is a value obtained by subtracting
a value of oil adhesion of the solid-phase polymerization oil agent
remaining on the fiber from a value of oil adhesion rate determined
for a fiber after being added with the finishing oil agent by a
method described in Section D in Examples.
[0147] Further, in cases where improvement of abrasion resistance
is required for intended use of the liquid crystalline polyester
fiber such as screen gauze or monofilament for filters, it is
preferred to carry out a high temperature heat treatment at a
temperature of Tm.sub.1+10.degree. C. or more after the cleaning.
Tm.sub.1 that is referred here indicates a value determined by a
measurement method described in Section E in Examples. Tm.sub.1 is
the melting point of fiber. By subjecting the liquid crystalline
polyester fiber to a heat treatment at a temperature that is as
high as the melting point +10.degree. C. or more, a half width of
peak at Tm.sub.1 is 15.degree. C. or more, and the degree of
crystallization and integrity of crystal of the whole fiber
decrease, thereby markedly improve the abrasion resistance.
[0148] In respect of heat treatment, although there is a
solid-phase polymerization of a liquid crystalline polyester fiber,
unless the treatment temperature in this case is set at a
temperature lower than the melting point of the fiber, the fibers
are fused and broken by being molten. In the case of solid-phase
polymerization, although a final temperature of the solid-phase
polymerization may increase up to a temperature higher than the
melting point of the fibers before the treatment because the
melting point of the fiber increases accompanying with the
treatment, even in such a case, the treatment temperature is lower
than the melting point of the fibers being treated, that is, the
melting point of the fibers after the heat treatment. That is, the
high-temperature heat treatment that is referred here increases the
abrasion resistance by decreasing a structural difference between a
dense crystal portion formed by a solid-phase polymerization and an
amorphous portion, that is, by decreasing the degree of
crystallization and the integrity of crystal, without carrying out
a solid-phase polymerization.
[0149] Therefore, even if Tm.sub.1 varies by the heat treatment,
the temperature is preferably set at a temperature of Tm.sub.1 of
the fibers after the treatment +10.degree. C. or higher, more
preferably at a temperature of the Tm.sub.1+40.degree. C. or
higher, still more preferably at a temperature of the
Tm.sub.1+60.degree. C. or higher, and in particular preferably at a
temperature of the Tm.sub.1+80.degree. C. or higher. The upper
limit of the heat treatment temperature is a temperature at which
the fibers melt down and is, it varies depending on tension, speed,
single-fiber fineness, treatment length, about Tm.sub.1+300.degree.
C., although.
[0150] Further, as another heat treatment, there is a heat
stretching of a liquid crystal polyester fiber, but the heat
stretching is a process tensing the fibers at a high temperature,
the orientation of molecular chain in the fiber structure becomes
high, the strength and the elastic modulus increase, and the degree
of crystallization and the integrity of crystal are maintained as
they are, that is, .DELTA.Hm.sub.1 is maintained to be high and the
half width of the peak Tm.sub.1 is maintained to be small.
Therefore, it becomes a fiber structure being inferior in abrasion
resistance, and the treatment is different from the heat treatment
in the present invention that aims to increase the abrasion
resistance by decreasing the degree of crystallization (decreasing
.DELTA.Hm.sub.1) and decreasing the integrity of crystal
(increasing the half width of the peak). It is noted that, because
the degree of crystallization decreases in the high temperature
heat treatment that is referred in the present invention, the
strength and elastic modulus do not increase.
[0151] It is preferred that the high-temperature heat treatment be
carried out as running the fibers continuously, because the fusion
bonding between fibers can be prevented and the uniformity of the
treatment can be enhanced. At that time, it is preferred that a
non-contact heat treatment be carried out to prevent generating the
fibrils and achieve uniform treatment. As means of heating, there
are a heating of the atmosphere, a radiation heating with a laser
or an infrared ray, or the like. A heating by a slit heater with a
block or a plate heater because it has both advantages of the
atmosphere heating and radiation heating and it can enhance the
stability for the treatment.
[0152] The treatment time is preferably longer from a viewpoint of
decreasing the degree of crystallinity and the integrity of
crystal, and is specifically preferably 0.01 seconds or longer,
more preferably 0.05 seconds or longer, and still more preferably
0.1 seconds or longer. Further, the upper limit of the treatment
time is preferably 5.0 seconds or less, more preferably 3.0 seconds
or less, and still more preferably 2.0 seconds or less, from a
viewpoint that the facility load should be reduced and that the
treatment time should be shortened so that the orientation of the
molecular chain is prevented from relaxing to decrease the strength
and elastic modulus.
[0153] If the tension of the fiber being treated is excessively
high, a melt breakage is likely to occur, and in cases where the
heat treatment is carried out at a condition of being applied with
an excessive tension, because a decrease of the degree of
crystallization is small and the advantage for improving the
abrasion resistance becomes low, it is preferred to control the
tension as low as possible. In this point, it is explicitly
different from a heat stretching. However, if the tension is too
low, the running of the fibers becomes unstable and the treatment
becomes nonuniform, and therefore, it is preferably 0.001 cN/dtex
or more and 1.0 cN/dtex or less, more preferably 0.1 cN/dtex or
more and 0.3 cN/dtex or less.
[0154] Further, when a high-temperature heat treatment is carried
out while running, the tension is preferably as low as possible;
and stretching and relaxation may be added as appropriate. However,
if the tension is too low, the running of the fibers becomes
unstable and the treatment becomes nonuniform, and therefore, the
relaxation rate is preferably 2% or less (0.98 times or higher as
the draw ratio). Further, if the tension is too high, a melt
breakage due to heat is likely to occur, and in cases where the
heat treatment is carried out at a condition of being applied with
an excessive tension, because the decrease of the degree of
crystallization is small and the effect of improving the abrasion
resistance becomes low, the stretching ratio is preferably less
than 10% (1.10 times as the draw ratio), although it depends on the
temperature of the heat treatment. It is more preferably less than
5% (1.05 times as the draw ratio), still more preferably less than
3% (1.03 times). It is noted that the draw ratio is defined as a
quotient obtained by dividing the second roller speed by the first
roller speed when the heat treatment is performed between the
rollers (between the first roller and the second roller).
[0155] As the treatment speed becomes greater, a high-temperature
short-time treatment becomes possible and the effect for improving
the abrasion resistance increases, and even the productivity
improves. Therefore, although depending upon the treatment length,
the treatment speed is preferably 100 m/min or more, more
preferably 200 m/min or more, still more preferably 300 m/min or
more. The upper limit of the treatment speed is about 1,000 m/min
from a viewpoint of the running stability of the fiber.
[0156] With respect to the treatment length, although depending
upon the heating method, in the case of non-contact heating, in
order to carry out a uniform treatment, it is preferably 100 mm or
more, more preferably 200 mm or more, still more preferably 500 mm
or more. Further, because, if the treatment length is excessively
long, a treatment irregularity and melt breakage of fibers occur
ascribed to yarn swinging in the heater, it is preferably 3,000 mm
or less, more preferably 2,000 mm or less, and still more
preferably 1,000 mm or less.
EXAMPLES
[0157] By way of examples the present invention will now be more
specifically described below. Each of the characteristic values was
determined by the following methods.
A. Running Tension Fluctuation Range (R)
[0158] A washer tensor Y-601L manufactured by Yuasa Yarn Guide
Engineering Co., Ltd. was used with a scale of a dial being set to
0 (at that time, two pipe guides were lined up so as to be
perpendicular to a fiber running direction). A liquid crystalline
polyester fiber was forced to run onto the outer side of either one
of two pipe guides. Two washers (TW-3) were inserted in the pipe
guide where the fiber is forced to run such that the fiber was
forced to run therebetween (an angle formed by the running yarn was
about 90.degree.) at a speed of 30 m/min. The tension of running
yarn was continuously measured at a position of 5 to 10 cm
downstream from the tensor by P/C compatible tension meter
manufactured by Intec Co., Ltd. (model: IT-NR) for 10 minutes and
data was collected with Damping-timer of EEPROM being set to 3 in
attached Tension Star V1.14. Of the continuous data obtained during
the 10 minutes, from the maximum value (F.sub.max) and minimum
value (F.sub.min), the running tension fluctuation range (R) was
calculated by the following equation.
(Running tension fluctuation range (R))=F.sub.max-F.sub.min
B. Total Fineness and Fineness of Single Fiber
[0159] The fiber was taken by 10 m as a hank by a sizing reel, the
weight (g) thereof was multiplied at 1,000 times, 10 measurements
per 1 sample were carried out, and the average value was defined as
the fiber fineness (dtex). A quotient calculated by dividing this
with a number of filaments was defined as a fineness of single
fiber (dtex).
C. Strength, Elongation, and Elastic Modulus
[0160] Based on the method described in JIS L1013 (1999), at a
condition of a sample length of 100 mm and a tensile speed of 50
mm/min, 10 times measurement per one sample was carried out using
Tensilon UCT-100 manufactured by Orientec Co., Ltd., and the
average values were determined as a tenacity (cN), a strength
(cN/dtex), an elongation (%) and elastic modulus (cN/dtex). The
elastic modulus refers to an initial tensile resistance degree.
D. Amount of Oil Adhesion
[0161] Taking a fiber of 100.+-.10 mg, the weight thereof after
drying at 60.degree. C. for 10 minutes was measured (W.sub.0), the
fiber was dipped in a solution prepared by adding sodium
dodecylbenzene sulfonate to water of 100 times or more of the fiber
weight at 2.0 wt % relative to the fiber weight, the fiber was
subjected to a ultrasonic wave cleaning for 20 minutes, the fiber
after the cleaning was rinsed with water, the weight after drying
at 60.degree. C. for 60 minutes was measured (W1), and the amount
of oil adhesion was calculated by the following equation.
(Amount of oil adhesion (wt
%))=(W.sub.0-W.sub.1).times.100/W.sub.1
[0162] The amount of oil adhesion of solid-phase polymerization oil
agent and the amount of residual oil adhesion of solid-phase
polymerization oil agent were calculated by the calculation method
described above.
E. Tm.sub.1 of Liquid Crystalline Polyester Fiber, Half Width of
Peak at Tm.sub.1, .DELTA.Hm.sub.1, and Melting Point of Liquid
Crystalline Polyester Polymer
[0163] Differential calorimetry was carried out by DSC 2920
manufactured by TA Instruments Corporation, a temperature of
endothermic peak observed when measured under a condition of
heating from 50.degree. C. at a temperature elevation rate of
20.degree. C./min was referred to as Tm.sub.1 (.degree. C.), and
the half width of the peak (.degree. C.) and the heat of melting
(.DELTA.Hm.sub.1) (J/g) at Tm.sub.1 were measured.
[0164] With regard to the liquid crystalline polyester polymer
shown in Reference Examples, an endothermic peak observed when once
cooled down to 50.degree. C. under a condition of a temperature
lowering rate of 20.degree. C./min after maintained for five
minutes at a temperature of Tm.sub.1+20.degree. C. after
observation of Tm.sub.1 was referred to as Tm2, and this Tm2 was
referred to as the melting point of the polymer.
F. Polystyrene Equivalent Weight Average Molecular Weight
(Molecular Weight)
[0165] Using a mixed solvent of pentafluoro phenol/chloroform=35/65
(weight ratio) as the solvent, a sample for GPC measurement was
prepared by dissolution so that the concentration of liquid
crystalline polyester became 0.04 to 0.08 weight/volume %. In cases
where there is an insoluble substance even after allowed to stand
at a room temperature for 24 hours, the sample was allowed to stand
for another 24 hours, and then, a supernatant was taken as the
sample. This was measured using a GPC measurement device
manufactured by Waters Corporation, and the weight average
molecular weight (Mw) was determined in terms of a
polystyrene-equivalent weight average molecular weight.
[0166] Column: Shodex K-806M; two pieces, K-802; one piece
[0167] Detector: Differential refractive index detector RI (2414
type)
[0168] Temperature: 23.+-.2.degree. C.
[0169] Flow rate: 0.8 mL/min
[0170] Injection amount: 200 .mu.L
G. Median Diameter (D50)
[0171] Measurement of particle size was carried out by a laser
diffraction particle size distribution analyzer SALD-2000J
manufactured by Shimadzu Corporation to determine a median diameter
(D50).
H. Amount of Scum Generated
[0172] A washer tensor Y-601L manufactured by Yuasa Yarn Guide
Engineering Co., Ltd. was used with a scale of a dial being set to
0 (at that time, two pipe guides were lined up so as to be
perpendicular to a fiber running direction). A liquid crystalline
polyester fiber was forced to run onto the outer side of either one
of two pipe guides. Two washers (TW-3) were inserted in the pipe
guide where the fiber is forced to run such that the fiber was
forced to run therebetween (an angle formed by the running yarn was
about 90.degree.). A fiber of a length of 100,000 m was forced to
run at a speed of 400 m/min. The washer weight of the fiber before
and after the running was measured by an analytical electric
balance (EP214C) manufactured by Mettler-Toledo International Inc.
to calculate a value represented by the following equation. The
length of fiber that was forced to run could be selected from
between 25,000 m and 100,000 m. When the length of fiber was less
than 100,000 m, the amount of scum generated equivalent of a fiber
length of 100,000 m was proportionally calculated from the length
of fiber forced to run.
Amount of scum generated (g)=(washer weight after fiber
running)-(washer weight before fiber running)
I. Weavability and Fabric Characteristic Evaluation
[0173] Using a polyester monofilament as a warp yarn in a rapier
weaving machine, a weft driving test of a liquid crystalline
polyester fiber used as a weft yarn was carried out at a condition
of weaving density of 250/inch (2.54 cm) for both of warp and weft
yarns and a driving speed of 100 times/min. At that time, the
process passability was determined from accumulation of scum to the
yarn supply port (ceramic guide) in a test weaving at a width of
180 cm and a length of 100 cm, the weavability was determined from
the times of machine stopping due to yarn breakage, and the quality
of fabric was determined from the number of scum contaminated into
the yarn supply port. The respective determination criteria are as
follows. In cases where the number of the times of machine stopping
exceeded 15 times, the weaving was judged to be not feasible and
the evaluation of the weaving was discontinued.
<Process Passability>
[0174] Scum is not recognized by observation even after the
weaving: excellent (A)
[0175] Scum is recognized after the weaving, but fiber running is
not affected: good (B)
[0176] Scum is recognized after the weaving, and fiber running
tension increases: (C)
<Weavability>
[0177] Machine stopping 5 times or less: excellent (A); 6 to 10
times: good (B); 11 times or more: not good (C)
<Quality of Fabric>
[0178] The number of contaminated scum 5 or less: excellent (A); 6
to 10: good (B); 11 or more: not good (C)
J. Effect of Suppressing Fusion Bonding
[0179] The package after the solid-phase polymerization was
attached to a free roll creel (which had an axis, bearings and a
freely-rotatable outer layer and which had no brakes and no drive
source), and therefrom a yarn was drawn out in a lateral direction
(in a fiber rounding direction), and unwound at 400 m/min for 30
minutes. Thereafter, the surface of the solid-phase polymerization
package was observed to evaluate an effect of suppressing fusion
bonding by the following criteria based on the presence of
fluff.
[0180] A: The fluff was not observed.
[0181] B: The fluff was observed at 1 to 2 sites.
[0182] C: The fluff was observed at 3 or more sites.
K. Running Stability
[0183] While being unwound, the liquid crystalline polyester fiber
was rolled on a first roller with separate roller rotating at 400
m/min by 6 rounds, successively rolled on a first roller with
separate roller rotating at 401 m/min by 6 rounds, and sucked by a
suction gun. After this operation was carried out for 30 minutes,
running stability was evaluated based on the number of times of
yarn swinging in a running state for 1 minute (the number of times
of the running yarn being taken by the roller) by the following
criteria.
[0184] A: The yarn swing 0 times
[0185] B: The yarn swing twice or less
[0186] C: The yarn swing 3 times or more
M. Post-Processability
[0187] As for a fiber after the adhesion rate for the fiber weight
was measured, the surface of 5 single fibers was observed at a
visual field of 500 .mu.m.times.700 .mu.m using an optical
microscope and post-processability was evaluated based on adhered
substances on the fiber surface by the following criteria.
[0188] A: There are 2 or less adhered substances on the fiber
surface.
[0189] B: There are 3 to 10 adhered substances on the fiber
surface.
[0190] C: There are 11 or more adhered substances on the fiber
surface.
Reference Example 1
[0191] p-hydroxy bezoate of 870 parts by weight, 4,4'-dihydroxy
biphenyl of 327 parts by weight, hydroquinone of 89 parts by
weight, terephthalic acid of 292 parts by weight, isophthalic acid
of 157 parts by weight and acetic anhydride of 1,460 parts by
weight (1.10 equivalent of the sum of phenolic hydroxyl group) were
charged into a reaction vessel of 5 L with an agitating blade and a
distillation tube. The temperature was elevated from a room
temperature to 145.degree. C. for 30 minutes while agitated under a
nitrogen gas atmosphere and then those in the reaction vessel were
brought into reaction at 145.degree. C. for 2 hours. Thereafter,
the temperature was elevated to 310.degree. C. for 4 hours.
[0192] The polymerization temperature was kept at 335.degree. C.
and the pressure was reduced to 133 Pa over 1.5 hours. The reaction
was further continued for 20 minutes, and at the time when the
torque reached 15 kg-cm, the condensation polymerization was
completed. Next, the inside of the reaction vessel was pressurized
at 0.1 MPa, a polymer was discharged as a strand-like material
through a die having one circular discharge port with a diameter of
10 mm, and it was pelletized by a cutter.
[0193] The composition, melting point, and molecular weight of the
obtained liquid crystalline polyester are as described in Table
1.
Reference Example 2
[0194] p-hydroxy bezoate of 907 parts by weight,
6-hydroxy-2-naphthoic acid of 457 parts by weight and acetic
anhydride of 946 parts by weight (1.03 mol equivalent of the sum of
phenolic hydroxyl group) were charged into a reaction vessel of 5 L
with an agitating blade and a distillation tube. The temperature
was elevated from a room temperature to 145.degree. C. over 30
minutes while agitated under a nitrogen gas atmosphere and then
those in the reaction vessel were brought into reaction at
145.degree. C. for 2 hours. Thereafter, the temperature was
elevated to 325.degree. C. over 4 hours.
[0195] The polymerization temperature was kept at 325.degree. C.
and the pressure was reduced to 133 Pa over 1.5 hours. The reaction
was further continued for 20 minutes, and at the time when the
torque reached the predetermined one, the condensation
polymerization was completed. Next, the inside of the reaction
vessel was pressurized at 0.1 MPa, a polymer was discharged as a
strand-like material through a die having one circular discharge
port with a diameter of 10 mm, and it was pelletized by a
cutter.
[0196] The composition, melting point, and molecular weight of the
obtained liquid crystalline polyester are as described in Table
1.
TABLE-US-00001 TABLE 1 Reference Reference Example 1 Example 2
p-hydroxy bezoate unit mol % 54 73 (Structural unit (I))
4,4'-dihydroxy biphenyl unit mol % 16 0 (Structural unit (II))
Hydroquinone unit mol % 7 0 (Structural unit (III)) Terephthalic
acid unit mol % 15 0 (Structural unit (IV)) Isophthalic acid unit
mol % 8 0 (Structural unit (V)) 6-hydroxy-2-naphthoic acid unit mol
% 0 27 Liquid crystalline Melting .degree. C. 320 318 polyester
characteristics point Molecular -- 10.4 .times. 10.sup.4 9.1
.times. 10.sup.4 weight
Example 1
[0197] Using the liquid crystalline polyester of Reference Example
1, vacuum drying was carried out at 160.degree. C. for 12 hours and
it was then melt extruded by a single-screw extruder of .PHI.15 mm
manufactured by Osaka Seiki Kosaku, and the polymer was supplied to
a spinning pack while metered by a gear pump. In the spinning pack,
the polymer was filtered using a metal nonwoven fabric filter, and
the polymer was discharged from a die with ten holes. The
discharged polymer was passed through a heat retaining region of 40
mm, and then cooled and solidified from the outer side of the yarn
by an annular cooling air with 25.degree. C. air flow. Thereafter,
a spinning oil agent whose main component was a fatty acid ester
compound was added, and all of the filaments were together wound to
a first godet roller. This was passed through a second godet roller
having the same speed and then all of the filaments except one
filament were sucked by a suction gun, and the remaining one
filament fiber was wound in a pirn form via a dancer arm using a
pirn winder (EFT type take up winder manufactured by Kamitsu
Seisakusho Ltd., no contact roller contacting with a wound
package). During the winding, no yarn breakage occurred and the
yarn formation property was good. The obtained fiber exhibited a
fineness of 6.0 dtex, a strength of 6.4 cN/dtex, an elongation of
1.4%, and an elastic modulus of 495 cN/dtex.
[0198] The fibers were rewound from this spun fiber package using
an SSP-MV type rewinder (contact length (winding stroke of the
innermost layer) of 200 mm, the number of winding of 8.7, taper
angle of 45.degree.) manufactured by Kamitsu Seisakusho Ltd. The
spun fibers are unwound in a vertical direction (in a direction
perpendicular to the fiber rounding direction). Without using a
speed-regulating roller, using an oiling roller (having a
stainless-steel roll with pear skin-finished surface), solid-phase
polymerization oil agent was fed, wherein talc with a median
diameter of 1.0 .mu.m, SG-2000 (manufactured by Nippon Talc Co.,
Ltd.) shown as Talc 1 in Table 2, as an inorganic particle (A), was
dispersed in the amount of 1.0 wt % into aqueous solution
containing 6.0 wt % phosphate-based compound (B.sub.1) represented
by the following chemical formula (4) as a phosphate-based compound
(B).
##STR00005##
[0199] A stainless-steel bobbin with holes and wound thereon with a
"Kevlar" felt (weight: 280 g/m.sup.2, thickness: 1.5 mm) was used
as a core member for the roll-back, and the surface pressure was
set to 100 gf (98.0665 cN). The oil adhesion rate of the
solid-phase polymerization oil agent onto the fiber after the
roll-back (a+b) was 15 wt %.
[0200] Next, the bobbin with holes was detached from the package
wound back, and solid-phase polymerization was carried out in a
condition of a package where the fibers were taken up on the
"Kevlar" felt. The solid-phase polymerization was carried out using
a closed type oven at a condition where the temperature was
elevated from a room temperature to 240.degree. C. over about 30
minutes, kept at 240.degree. C. for 3 hours, elevated to
290.degree. C. at a rate of 4.degree. C./hr and kept for 20 hours.
As the atmosphere, dehumidified nitrogen was supplied at a flow
rate of 20 NL/min, and it was discharged from an exhaust port so as
not to pressurize the inside.
[0201] The obtained fiber after the solid-phase polymerization
exhibited a fineness of 6.0 dtex, a strength of 24.5 cN/dtex, an
elongation of 2.6%, and an elastic modulus of 1,100 cN/dtex. The
strength, elongation and elastic modulus were improved as compared
with those before the solid-phase polymerization and thus it could
be confirmed that the solid-phase polymerization proceeded.
[0202] The fibers were unwound from the thus obtained package after
the solid-phase polymerization, and subjected to successively
washing for removing the solid-phase polymerization oil agent and
high-temperature non-contact heat treatment.
[0203] That is, the package after the solid-phase polymerization
was attached to a free roll creel (which had an axis, bearings and
a freely-rotatable outer layer and which had no brakes and no drive
source), and therefrom a yarn was drawn out in a lateral direction
(in a fiber rounding direction), and continuously, the fibers were
inserted into a bath (with no guides contacting to fibers inside),
which has a length of 150 cm (contact length of 150 cm), provided
with slits at both ends and the oil agent was washed and removed. A
wash solution containing nonionic-anionic surfactant (Gran Up US-30
manufactured by Sanyo Chemical Industries, Ltd.) by 1.0 wt % was
controlled to 50.degree. C. in an external tank, and was supplied
into a water tank by a pump. When supplied to the water tank, the
wash solution was supplied into the water tank through a pipe
having holes every 5 cm in the water tank, so as to give liquid
flow in the water tank by supplying through this pipe. There
provided a mechanism where the wash solution, which had been
overflowed from the slits and holes for adjusting liquid level, was
returned to the external tank.
[0204] The fibers after the washing were continuously inserted into
a bath (with no guides contacting to fibers inside) provided with
slits at both ends, which bath has a length of 23 cm (contact
length of 23 cm) and rinsed with 50.degree. C. heated water. The
fibers after the rinsing were passed through a bearing roller guide
to blow away water by applying air flow, and then the first roller
having a separate roller of 400 m/min. Because the creel is a free
roll, this roller is supposed to draw fibers so as to unwind from
the solid-phase polymerized package and to run the fibers.
[0205] The fiber that had passed through the roller was driven
between slit heaters of a length of 1 m, which are heated to
510.degree. C., to be subjected to high-temperature non-contact
heat treatment. The slit heater was not provided with guides inside
with no contact between the heater and the fiber. The fibers which
had passed through the heater were passed through the second roller
having a separate roller. Speeds are set to the same between the
first roller and the second roller. The fibers that had passed
through the second roller were given finishing oil having a fatty
acid ester compound as a main constituent using an oiling roller
made of ceramic, and was taken up by an EFT type bobbin traverse
winder (manufactured by Kamitsu Seisakusho Ltd.).
[0206] The characteristics of the obtained fiber are as shown in
Table 2. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
excellent as well.
[0207] The obtained fiber exhibited a Tm.sub.1 of 339.degree. C., a
.DELTA.Hm.sub.1 of 0.5 J/g, a half width of peak at Tm.sub.1 of
31.degree. C., and an amount of scum generated of 0.0003 g.
[0208] From the above result, the tension fluctuation was small and
the scum generation was suppressed in practical warping and weaving
steps as well. It would be expected to have excellent
characteristics with few defects when made to a mesh woven fabric
for a screen gauze for printing, a filter or the like.
Examples 2 to 6
[0209] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the rotation
number of the oiling roller at the time of the winding back was
altered and the oil adhesion rate of solid-phase polymerization oil
agent to the fiber after the winding back (a+b) was altered as
shown in Table 2.
[0210] The characteristics of the obtained fiber are as shown in
Table 2. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
excellent as well.
[0211] The fiber that was obtained in Example 2 exhibited a
Tm.sub.1 of 332.degree. C., a .DELTA.Hm.sub.1 of 0.6 J/g, a half
width of peak at Tm.sub.1 of 29.degree. C., and an amount of scum
generated of 0.0005 g. The fiber that was obtained in Example 3
exhibited a Tm.sub.1 of 335.degree. C., a .DELTA.Hm.sub.1 of 0.7
J/g, a half width of peak at Tm.sub.1 of 28.degree. C., and an
amount of scum generated of 0.0007 g. The fiber that was obtained
in Example 4 exhibited a Tm.sub.1 of 337.degree. C., a
.DELTA.Hm.sub.1 of 0.5 J/g, a half width of peak at Tm.sub.1 of
26.degree. C., and an amount of scum generated of 0.0005 g. The
fiber that was obtained in Example 5 exhibited a Tm.sub.1 of
331.degree. C., a .DELTA.Hm.sub.1 of 0.7 J/g, a half width of peak
at Tm.sub.1 of 28.degree. C., and an amount of scum generated of
0.0004 g. The fiber that was obtained in Example 6 exhibited a
Tm.sub.1 of 334.degree. C., a .DELTA.Hm.sub.1 of 0.6 J/g, a half
width of peak at Tm.sub.1 of 27.degree. C., and an amount of scum
generated of 0.0006 g.
[0212] From the above result, the tension fluctuation was small and
the scum generation was suppressed in practical warping and weaving
steps as well. It would be expected to have excellent
characteristics with few defects when made to a mesh woven fabric
for a screen gauze for printing, a filter or the like.
TABLE-US-00002 TABLE 2 Example 1 Example 2 Example 3 Example 4
Example 5 Example 6 Liquid crystalline polyesterpolymer --
Reference Reference Reference Reference Reference Reference Example
1 Example 1 Example 1 Example 1 Example 1 Example 1 Inorganic
particle (A) -- Talc 1 Talc 1 Talc 1 Talc 1 Talc 1 Talc 1 Median
diameter (D50) .mu.m 1.0 1.0 1.0 1.0 1.0 1.0 Phosphate-based
compound (B) -- Phosphate- Phosphate- Phosphate- Phosphate-based
Phosphate-based Phosphate-based based based based compound
(B.sub.1) based compound (B.sub.1) compound compound compound
(B.sub.1) (B.sub.1) (B.sub.1) Oil adhesion rate of solid-phase wt %
15 1.0 2.1 4.7 20 30 polymerization oil agent (a + b) a wt % 2.1
0.14 0.30 0.67 2.9 4.3 b/a -- 6 6 6 6 6 6 The presence of cleaning
step -- Present Present Present Present Present Present The
presence of high temperature -- Present Present Present Present
Present Present heat treatment step The number of filaments
Filaments 1 1 1 1 1 1 Single fiber fineness dtex 6.0 6.0 6.0 6.0
6.0 6.0 Strength cN/dtex 17.9 16.9 17.3 17.7 17.8 17.9 Elongation %
2.8 2.6 2.7 2.6 2.7 2.7 Elastic modulus cN/dtex 754 698 728 747 748
758 The presence of particulates in -- Absent Absent Absent Absent
Absent Absent finishing oil agent Oil adhesion rate % 0.9 1 1 1.1
0.9 1 Oil adhesion rate of residual solid- % 0.1 0.1 0.2 0.1 0.1
0.1 phase polymerization oil agent Oil adhesion rate of finishing
oil % 0.8 0.9 0.8 1.0 0.8 0.9 agent Running tension fluctuation
range cN 3.2 3.4 3.5 3.6 3.4 3.7 (R) Process passability -- A A A A
A A Weavability -- A A A A A A (0 times) (Once) (0 times) (0 times)
(Twice) (Once) Quality of woven fabric -- A A A A A A (0) (0) (0)
(0) (0) (0)
Example 7
[0213] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the number of
filaments was set to 10 in the spinning step.
[0214] The characteristics of the obtained fiber are as shown in
Table 3. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
excellent as well.
[0215] The fiber that was obtained in Example 7 exhibited a
Tm.sub.1 of 338.degree. C., a .DELTA.Hm.sub.1 of 1.3 J/g, a half
width of peak at Tm.sub.1 of 25.degree. C., and an amount of scum
generated of 0.0012 g.
[0216] From the above result, the tension fluctuation was small and
the scum generation was suppressed in practical warping and weaving
steps as well. It would be expected to have excellent
characteristics with few defects when made to a mesh woven fabric
for a screen gauze for printing, a filter or the like.
[0217] The fiber obtained in the spinning exhibited a fineness of
6.0 dtex, a strength of 6.1 cN/dtex, an elongation of 1.3%, and an
elastic modulus of 463 cN/dtex; and the fiber after the solid-phase
polymerization exhibited a fineness of 6.0 dtex, a strength of 23.6
cN/dtex, an elongation of 2.5%, and an elastic modulus of 1,058
cN/dtex. The strength, elongation and elastic modulus were improved
as compared with those of the fiber before the solid-phase
polymerization and thus it was confirmed that the solid-phase
polymerization proceeded.
Example 8
[0218] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that "SYLYSIA"310P
(manufactured by Fuji Silysia Chemical Ltd.) which was silica was
used as the inorganic particle (A).
[0219] The characteristics of the obtained fiber are as shown in
Table 3. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
excellent as well.
[0220] The fiber that was obtained in Example 8 exhibited a
Tm.sub.1 of 337.degree. C., a .DELTA.Hm.sub.1 of 0.5 J/g, a half
width of peak at Tm.sub.1 of 28.degree. C., and an amount of scum
generated of 0.0010 g.
[0221] From the above result, the tension fluctuation was small and
the scum generation was suppressed in practical warping and weaving
steps as well. It would be expected to have excellent
characteristics with few defects when made to a mesh woven fabric
for a screen gauze for printing, a filter or the like.
Example 9
[0222] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that "MICRO ACE"
(registered trademark) P-2 (manufactured by Nippon Talc Co., Ltd.)
which was a talc of a median diameter 7.0 .mu.m shown as Talc 2 in
Table 3 was used as the inorganic particle (A).
[0223] The characteristics of the obtained fiber are as shown in
Table 3. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
good.
[0224] The fiber that was obtained in Example 9 exhibited a
Tm.sub.1 of 334.degree. C., a .DELTA.Hm.sub.1 of 0.6 J/g, a half
width of peak at Tm.sub.1 of 24.degree. C., and an amount of scum
generated of 0.0010 g.
[0225] From the above result, although there were some concerns
about yarn breakage, the tension fluctuation was small and the scum
generation was suppressed in practical warping and weaving steps as
well. It would be expected to have excellent characteristics with
few defects when made to a mesh woven fabric for a screen gauze for
printing, a filter or the like.
[0226] As for factors causing slightly lower weavability than
Example 1, it is presumed that, due to the large median diameter of
the inorganic particle, very minor fusion bonding occurred at the
time of the solid-phase polymerization of the fiber, which caused
deterioration of fiber characteristics and resulted in yarn
breakage at the time of weaving.
Example 10
[0227] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that "TALCAN POWDER"
(registered trademark) PK-C (manufactured by Hayashi Kasei Co.,
Ltd.) which was a talc of a median diameter 11 .mu.m shown in Table
3 as Talc 3 was used as the inorganic particle (A).
[0228] The characteristics of the obtained fiber are as shown in
Table 3. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
good.
[0229] The fiber that was obtained in Example 10 exhibited a
Tm.sub.1 of 334.degree. C., a .DELTA.Hm.sub.1 of 0.7 J/g, a half
width of peak at Tm.sub.1 of 28.degree. C., and an amount of scum
generated of 0.0009 g.
[0230] From the above result, although there were some concerns
about yarn breakage, the tension fluctuation was small and the scum
generation was suppressed in practical warping and weaving steps as
well. It would be expected to have excellent characteristics with
few defects when made to a mesh woven fabric for a screen gauze for
printing, a filter or the like.
[0231] As for factors causing slightly lower weavability than
Example 1, it is presumed that, due to the large median diameter of
the inorganic particle, very minor fusion bonding occurred at the
time of the solid-phase polymerization of the fiber, which caused
deterioration of fiber characteristics and resulted in yarn
breakage at the time of weaving.
TABLE-US-00003 TABLE 3 Example 7 Example 8 Example 9 Example 10
Liquid crystalline polyesterpolymer -- Reference Reference
Reference Reference Example 1 Example 1 Example 1 Example 1
Inorganic particle (A) -- Talc 1 Silica Talc 2 Talc 3 Median
diameter (D50) .mu.m 1.0 2.7 7.0 11 Phosphate-based compound (B) --
Phosphate-based Phosphate-based Phosphate-based Phosphate-based
compound (B.sub.1) compound (B.sub.1) compound (B.sub.1) compound
(B.sub.1) Oil adhesion rate of solid-phase wt % 15 15 15 15
polymerization oil agent (a + b) a wt % 2.1 2.1 2.1 2.1 b/a -- 6 6
6 6 The presence of cleaning step -- Present Present Present
Present The presence of high temperature -- Present Present Present
Present heat treatment step The number of filaments Filaments 10 1
1 1 Single fiber fineness dtex 6.0 6.0 6.0 6.0 Strength cN/dtex
17.3 17.6 17.2 16.8 Elongation % 2.6 2.7 2.6 2.4 Elastic modulus
cN/dtex 729 748 724 697 The presence of particulates in -- Absent
Absent Absent Absent finishing oil agent Oil adhesion rate % 1.9
0.8 1 1.2 Oil adhesion rate of residual solid- % 0.2 0.1 0.1 0.2
phase polymerization oil agent Oil adhesion rate of finishing oil %
1.7 0.7 0.9 1.0 agent Running tension fluctuation range cN 4.9 3.9
3.8 4.0 (R) Process passability -- A A A A Weavability -- A A B B
(4 times) (4 times) (6 times) (10 times) Quality of woven fabric --
A (3) A (2) A (1) A (2)
Examples 11 to 14
[0232] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the amount of
dispersion of the inorganic particle (A) in the solid-phase
polymerization oil agent and the adhesion rate (a) wt % of the
inorganic particle to the fiber was altered as shown in Table
4.
[0233] The characteristics of the obtained fiber are as shown in
Table 4. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
excellent or good as well.
[0234] The fiber that was obtained in Example 11 exhibited a
Tm.sub.1 of 336.degree. C., a .DELTA.Hm.sub.1 of 0.5 J/g, a half
width of peak at Tm.sub.1 of 29.degree. C., and an amount of scum
generated of 0.0012 g. The fiber that was obtained in Example 12
exhibited a Tm.sub.1 of 337.degree. C., a .DELTA.Hm.sub.1 of 0.7
J/g, a half width of peak at Tm.sub.1 of 27.degree. C., and an
amount of scum generated of 0.0007 g. The fiber that was obtained
in Example 13 exhibited a Tm.sub.1 of 332.degree. C., a
.DELTA.Hm.sub.1 of 0.6 J/g, a half width of peak at Tm.sub.1 of
24.degree. C., and an amount of scum generated of 0.0007 g. The
fiber that was obtained in Example 14 exhibited a Tm.sub.1 of
333.degree. C., a .DELTA.Hm.sub.1 of 0.5 J/g, a half width of peak
at Tm.sub.1 of 26.degree. C., and an amount of scum generated of
0.0011 g.
[0235] From the above result, the tension fluctuation was small and
the scum generation was suppressed in practical warping and weaving
steps as well. It would be expected to have excellent
characteristics with few defects when made to a mesh woven fabric
for a screen gauze for printing, a filter or the like.
[0236] As for factors causing slightly lower weavability than
Example 1 in Example 11, it is presumed that, due to the smaller
amount of the inorganic particle (A) added, some fusion bonding
occurred at the time of the solid-phase polymerization of the
fiber, which caused deterioration of fiber characteristics and
resulted in yarn breakage at the time of weaving.
[0237] As for factors causing slightly lower weavability than
Example 1 in Example 14, it is presumed that, due to the larger
amount of the inorganic particle (A) added, adhesion became spotty
and some fusion bonding occurred at the time of the solid-phase
polymerization of the fiber, which caused deterioration of fiber
characteristics and resulted in yarn breakage at the time of
weaving.
Examples 15 and 16
[0238] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the
phosphate-based compound (B) was, as shown in Table 4, altered to a
phosphate-based compound (B.sub.2) represented by the following
chemical formula (5) or a phosphate-based compound (B.sub.3)
represented by the following chemical formula (6).
##STR00006##
[0239] The characteristics of the obtained fiber are as shown in
Table 4. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
excellent as well.
[0240] The fiber that was obtained in Example 15 exhibited a
Tm.sub.1 of 329.degree. C., a .DELTA.Hm.sub.1 of 0.5 J/g, a half
width of peak at Tm.sub.1 of 28.degree. C., and an amount of scum
generated of 0.0006 g. The fiber that was obtained in Example 16
exhibited a Tm.sub.1 of 330.degree. C., a .DELTA.Hm.sub.1 of 0.6
J/g, a half width of peak at Tm.sub.1 of 27.degree. C., and an
amount of scum generated of 0.0007 g.
[0241] From the above result, the tension fluctuation was small and
the scum generation was suppressed in practical warping and weaving
steps as well. It would be expected to have excellent
characteristics with few defects when made to a mesh woven fabric
for a screen gauze for printing, a filter or the like.
TABLE-US-00004 TABLE 4 Example 11 Example 12 Example 13 Example 14
Example 15 Example 16 Liquid crystalline polyesterpolymer --
Reference Reference Reference Reference Reference Reference Example
1 Example 1 Example 1 Example 1 Example 1 Example 1 Inorganic
particle (A) -- Talc 1 Talc 1 Talc 1 Talc 1 Talc 1 Talc 1 Median
diameter (D50) .mu.m 1.0 1.0 1.0 1.0 1.0 1.0 Phosphate-based
compound (B) -- Phosphate- Phosphate- Phosphate- Phosphate-based
Phosphate-based Phosphate-based based based based compound
(B.sub.1) compound (B.sub.1) compound (B.sub.1) compound compound
compound (B.sub.1) (B.sub.1) (B.sub.1) Oil adhesion rate of
solid-phase wt % 15 15 15 15 15 15 polymerization oil agent (a + b)
a wt % 0.009 0.05 5.0 7.6 2.1 2.1 b/a -- 1666 299 2 0.97 6 6 The
presence of cleaning step -- Present Present Present Present
Present Present The presence of high temperature -- Present Present
Present Present Present Present heat treatment step The number of
filaments Filaments 1 1 1 1 1 1 Single fiber fineness dtex 6.0 6.0
6.0 6.0 6.0 6.0 Strength cN/dtex 16.7 17.2 17.9 16.8 17.8 17.9
Elongation % 2.6 2.7 2.7 2.7 2.6 2.7 Elastic modulus cN/dtex 694
719 755 698 753 738 The presence of particulates in -- Absent
Absent Absent Absent Absent Absent finishing oil agent Oil adhesion
rate % 0.9 1 1.2 1.4 1 1.2 Oil adhesion rate of residual solid- %
0.1 0.1 0.3 0.4 0.1 0.2 phase polymerization oil agent Oil adhesion
rate of finishing oil % 0.8 0.9 0.9 1.0 0.9 1 agent Running tension
fluctuation range cN 3.5 2.4 3.3 3.4 3.3 1.5 (R) Process
passability -- A A A A A A Weavability -- B A A B A A (8 times)
(Once) (Once) (6 times) (Twice) (Once) Quality of woven fabric -- A
A A A A A (0) (1) (1) (1) (0) (0)
Examples 17 and 18
[0242] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the discharge
amount in the spinning step was altered to change the fineness.
[0243] The characteristics of the obtained fiber are as shown in
Table 5. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
excellent as well.
[0244] The fiber that was obtained in Example 17 exhibited a
Tm.sub.1 of 338.degree. C., a .DELTA.Hm.sub.1 of 0.5 J/g, a half
width of peak at Tm.sub.1 of 29.degree. C., and an amount of scum
generated of 0.0007 g. The fiber that was obtained in Example 18
exhibited a Tm.sub.1 of 336.degree. C., a .DELTA.Hm.sub.1 of 0.7
J/g, a half width of peak at Tm.sub.1 of 26.degree. C., and an
amount of scum generated of 0.0006 g.
[0245] From the above result, the tension fluctuation was small and
the scum generation was suppressed in practical warping and weaving
steps as well. It would be expected to have excellent
characteristics with few defects when made into a mesh woven fabric
for a screen gauze for printing, a filter or the like.
[0246] The fiber obtained in the spinning in Example 17 exhibited a
fineness of 4.0 dtex, a strength of 5.8 cN/dtex, an elongation of
1.3%, and an elastic modulus of 460 cN/dtex; and the fiber after
the solid-phase polymerization exhibited a fineness of 4.0 dtex, a
strength of 21.0 cN/dtex, an elongation of 2.3%, and an elastic
modulus of 1,059 cN/dtex. The strength, elongation and elastic
modulus were improved as compared with those of the fiber before
the solid-phase polymerization and thus it was confirmed that the
solid-phase polymerization proceeded.
[0247] Further, the fiber obtained in the spinning in Example 18
exhibited a fineness of 13.0 dtex, a strength of 6.1 cN/dtex, an
elongation of 1.3%, and an elastic modulus of 484 cN/dtex; and the
fiber after the solid-phase polymerization exhibited a fineness of
13.0 dtex, a strength of 20.5 cN/dtex, an elongation of 2.2%, and
an elastic modulus of 945 cN/dtex. The strength, elongation and
elastic modulus were improved as compared with those of the fiber
before the solid-phase polymerization and thus it was confirmed
that the solid-phase polymerization proceeded.
Example 19
[0248] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the temperature
was not increased in the slit heater and the high-temperature
non-contact heat treatment was not carried out.
[0249] The characteristics of the obtained fiber are as shown in
Table 5. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
good as well.
[0250] The fiber that was obtained in Example 19 exhibited a
Tm.sub.1 of 345.degree. C., a .DELTA.Hm.sub.1 of 7.8 J/g, a half
width of peak at Tm.sub.1 of 6.3.degree. C., and an amount of scum
generated of 0.0012 g.
[0251] From the above result, although there were some concerns
about yarn breakage, the tension fluctuation was small and the scum
generation was suppressed in practical warping and weaving steps as
well. It would be expected to have excellent characteristics with
few defects when made into a mesh woven fabric for a screen gauze
for printing, a filter or the like.
[0252] As for factors causing slightly lower weavability than
Example 1, it is presumed that, because the heat treatment was not
carried out, fibrils were easy to be generated by scratches in the
step, which resulted in yarn breakage at the time of weaving.
Example 20
[0253] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 19 except that the liquid
crystalline polyester polymer of Reference Example 2 at the time of
the spinning.
[0254] The characteristics of the obtained fiber are as shown in
Table 5. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
good as well. Further, the fiber obtained in the spinning before
the solid-phase polymerization exhibited a fineness of 6.0 dtex, a
strength of 8.8 cN/dtex, an elongation of 2.0%, and an elastic
modulus of 532 cN/dtex. The strength, elongation and elastic
modulus were improved as compared with those before the solid-phase
polymerization and thus it was confirmed that the solid-phase
polymerization proceeded.
[0255] The fiber that was obtained in Example 20 exhibited a
Tm.sub.1 of 320.degree. C., a .DELTA.Hm.sub.1 of 11 J/g, a half
width of peak at Tm.sub.1 of 7.5.degree. C., and an amount of scum
generated of 0.0012 g.
[0256] From the above result, although there were some concerns
about yarn breakage, the tension fluctuation was small and the scum
generation was suppressed in practical warping and weaving steps as
well. It would be expected to have excellent characteristics with
few defects when made into a mesh woven fabric for a screen gauze
for printing, a filter or the like.
[0257] As for factors causing slightly lower weavability than
Example 1, it is presumed that, because the heat treatment was not
carried out, fibrils were easy to be generated by scratches in the
step, which resulted in yarn breakage at the time of weaving.
TABLE-US-00005 TABLE 5 Example 17 Example 18 Example 19 Example 20
Liquid crystalline polyesterpolymer -- Reference Reference
Reference Reference Example 1 Example 1 Example 1 Example 2
Inorganic particle (A) -- Talc 1 Talc 1 Talc 1 Talc 1 Median
diameter (D56) .mu.m 1.0 1.0 1.0 1.0 Phosphate-based compound (B)
-- Phosphate-based Phosphate-based Phosphate-based Phosphate-based
compound (B.sub.1) compound (B.sub.1) compound (B.sub.1) compound
(B.sub.1) Oil adhesion rate of solid-phase wt % 15 15 15 15
polymerization oil agent (a + b) a wt % 2.1 2.1 2.1 2.1 b/a -- 6 6
6 6 The presence of cleaning step -- Present Present Present
Present The presence of high temperature -- Present Present Absent
Absent heat treatment step The number of filaments Filaments 1 1 1
1 Single fiber fineness dtex 4.0 13.0 6.0 6.0 Strength cN/dtex 16.9
15.4 22.5 20.1 Elongation % 2.7 2.4 2.4 2.8 Elastic modulus cN/dtex
724 715 1081 851 The presence of particulates in -- Absent Absent
Absent Absent finishing oil agent Oil adhesion rate % 1 1 1.1 1.2
Oil adhesion rate of residual solid- % 0.2 0.1 0.2 0.2 phase
polymerization oil agent Oil adhesion rate of finishing oil % 0.8
0.9 0.9 1.0 agent Running tension fluctuation range cN 3.2 3.8 4.8
4.7 (R) Process passability -- A A A A Weavability -- A A B B (5
times) (Twice) (6 times) (7 times) Quality of woven fabric -- A (1)
A (2) A (1) A (2)
Examples 21 to 23
[0258] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the rotation
number of an oiling roller at the time of the addition of the
finishing oil agent was altered and the oil adhesion rate of the
finishing oil agent was altered.
[0259] The characteristics of the obtained fiber are as shown in
Table 6. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. The weavability was excellent or
good as well. It was confirmed that, as the oil adhesion rate of
the finishing oil agent increased, the frequency of yarn breakage
ascribed to pseudo adhesion of the fiber tended to increase to
lower the weavability.
[0260] The fiber that was obtained in Example 21 exhibited a
Tm.sub.1 of 338.degree. C., a .DELTA.Hm.sub.1 of 0.6 J/g, a half
width of peak at Tm.sub.1 of 24.degree. C., and an amount of scum
generated of 0.0007 g. The fiber that was obtained in Example 22
exhibited a Tm.sub.1 of 335.degree. C., a .DELTA.Hm.sub.1 of 0.7
J/g, a half width of peak at Tm.sub.1 of 27.degree. C., and an
amount of scum generated of 0.0007 g. The fiber that was obtained
in Example 23 exhibited a Tm.sub.1 of 337.degree. C., a
.DELTA.Hm.sub.1 of 0.5 J/g, a half width of peak at Tm.sub.1 of
23.degree. C., and an amount of scum generated of 0.0009 g.
[0261] From the above result, the tension fluctuation was small and
the scum generation was suppressed in practical warping and weaving
steps as well. It would be expected to have excellent
characteristics with few defects when made into a mesh woven fabric
for a screen gauze for printing, a filter or the like.
Example 24
[0262] The liquid crystalline polyester of Reference Example 1 and
polyetheretherketone polymer PEEK 90G (melting point 344.degree.
C., hereinafter PEEK) manufactured by Victrex Manufacturing Limited
were used. A blend fiber comprising liquid crystalline polyesters
was obtained by carrying out spinning, winding back, solid-phase
polymerization, cleaning, high temperature heat treatment in the
same manner as described in Example 1 except that the liquid
crystalline polyester and PEEK were mixed in the form of pellets at
a weight ratio of 90/10, and then melted and knead by an
extruder.
[0263] The characteristics of the obtained fiber are as shown in
Table 6. A slight decrease in the strength and elastic modulus was
observed when compared with those of the fiber of Example 1. Yet,
because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
good as well.
[0264] The fiber that was obtained in Example 24 exhibited a
Tm.sub.1 of 344.degree. C., a .DELTA.Hm.sub.1 of 4.4 J/g, a half
width of peak at Tm.sub.1 of 15.47.degree. C., and an amount of
scum generated of 0.0012 g.
[0265] From the above result, although there were some concerns
about yarn breakage, the tension fluctuation was small and the scum
generation was suppressed in practical warping and weaving steps as
well. It would be expected to have excellent characteristics with
few defects when made into a mesh woven fabric for a screen gauze
for printing, a filter or the like.
[0266] As for factors causing slightly lower weavability than
Example 1, it is presumed that, because it was a blend fiber of
different kinds of polymers, fibrils of the fiber were easy to be
generated by detachment at a polymer interface by scratches in the
step, which resulted in an increase in the number of times of yarn
breakage at the time of weaving.
[0267] The fiber obtained in the spinning exhibited a fineness of
6.0 dtex, a strength of 5.6 cN/dtex, an elongation of 1.2%, and an
elastic modulus of 432 cN/dtex; and the fiber after the solid-phase
polymerization exhibited a fineness of 6.0 dtex, a strength of 22.1
cN/dtex, an elongation of 2.3%, and an elastic modulus of 985
cN/dtex. The strength, elongation and elastic modulus were improved
as compared with those of the fiber before the solid-phase
polymerization and thus it was confirmed that the solid-phase
polymerization proceeded.
Example 25
[0268] A compound fiber comprising liquid crystalline polyesters at
a weight ratio of the core to the sheath of 70/30 was obtained by
carrying out spinning, winding back, solid-phase polymerization,
cleaning, high temperature heat treatment in the same manner as
described in Example 1 except that the liquid crystalline polyester
of Reference Example 1 and PEEK were used as a core component and
sheath polymer, respectively; and the liquid crystalline polyester
and PEEK that were melted by a separate extruder were supplied to a
die for core-sheath compound fiber.
[0269] The characteristics of the obtained fiber are as shown in
Table 6. A slight decrease in the strength and elastic modulus was
observed when compared with those of the fiber of Example 1. Yet,
because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. In addition, the weavability was
good as well.
[0270] The fiber that was obtained in Example 25 exhibited a
Tm.sub.1 of 344.degree. C., a .DELTA.Hm.sub.1 of 13 J/g, a half
width of peak at Tm.sub.1 of 16.degree. C., and an amount of scum
generated of 0.0010 g.
[0271] From the above result, although there were some concerns
about yarn breakage, the tension fluctuation was small and the scum
generation was suppressed in practical warping and weaving steps as
well. It would be expected to have excellent characteristics with
few defects when made into a mesh woven fabric for a screen gauze
for printing, a filter or the like.
[0272] As for factors causing slightly lower weavability than
Example 1, it is presumed that, because it was a core-sheath
compound fiber with a different kind of polymer, fibrils of the
fiber were easy to be generated by detachment at a polymer
interface by scratches in the step, which resulted in an increase
in the number of times of yarn breakage at the time of weaving.
[0273] The fiber obtained in the spinning exhibited a fineness of
6.0 dtex, a strength of 4.9 cN/dtex, an elongation of 1.0%, and an
elastic modulus of 343 cN/dtex; and the fiber after the solid-phase
polymerization exhibited a fineness of 6.0 dtex, a strength of 16.7
cN/dtex, an elongation of 1.7%, and an elastic modulus of 758
cN/dtex. The strength, elongation and elastic modulus were improved
as compared with those of the fiber before the solid-phase
polymerization and thus it was confirmed that the solid-phase
polymerization proceeded.
TABLE-US-00006 TABLE 6 Example 21 Example 22 Example 23 Example 24
Example 25 Liquid crystalline polyesterpolymer -- Reference
Reference Reference Reference Example Reference Example Example 1
Example 1 Example 1 1 (blend) 1 (composite) Inorganic particle (A)
-- Talc 1 Talc 1 Talc 1 Talc 1 Talc 1 Median diameter (D50) .mu.m
1.0 1.0 1.0 1.0 1.0 Phosphate-based compound (B) -- Phosphate-based
Phosphate-based Phosphate-based Phosphate-based Phosphate-based
compound (B.sub.1) compound (B.sub.1) compound (B.sub.1) compound
(B.sub.1) compound (B.sub.1) Oil adhesion rate of solid-phase wt %
15 15 15 15 15 polymerization oil agent (a + b) a wt % 2.1 2.1 2.1
2.1 2.1 b/a -- 6 6 6 6 6 The presence of cleaning step -- Present
Present Present Present Present The presence of high temperature --
Present Present Present Present Present heat treatment step The
number of filaments Filaments 1 1 1 1 1 Single fiber fineness dtex
6.0 6.0 6.0 6.0 6.0 Strength cN/dtex 17.8 17.8 17.7 16.3 13.8
Elongation % 2.8 2.8 2.8 2.5 2.2 Elastic modulus cN/dtex 752 736
727 624 498 The presence of particulates in -- Absent Absent Absent
Absent Absent finishing oil agent Oil adhesion rate % 1.5 2.0 3.0
1.0 1.0 Oil adhesion rate of residual solid- % 0.1 0.1 0.1 0.1 0.2
phase polymerization oil agent Oil adhesion rate of finishing oil %
1.4 1.9 2.9 0.9 0.8 agent Running tension fluctuation range cN 3.4
3.9 4.3 3.8 3.9 (R) Process passability -- A A A A A Weavability --
A A B B B (Once) (4 times) (7 times) (8 times) (9 times) Quality of
woven fabric -- A A A A A (0) (1) (1) (2) (3)
Reference Example 3
[0274] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the cleaning was
not carried out after the solid-phase polymerization step.
[0275] The characteristics of the obtained fiber are as shown in
Table 7. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was high; and the running tension
fluctuation range (R) was high, the process passability was good.
However, the weavability and quality of woven fabric were inferior.
The amount of scum generated of the fiber that was obtained in
Reference Example 3 was 0.0636 g.
[0276] From the above results, it is predicted that troubles occur
frequently when it is made to a mesh woven fabric for a screen
gauze for printing, a filter or the like. However, it is proven
from Reference Example 3 that, without carrying out the cleaning,
the fiber is coated with salts and particles which are powders on
the fiber surface, which decreases running resistance by an action
of powder mold releasing and can prevent fibrillation by scratch of
the fiber, thereby enhancing running stability. In addition, it is
implied that the fiber is excellent in processability because both
can be readily cleaned and removed by water and thus a state of
adhered substances being substantially absence on the fiber surface
by cleaning with water when the fiber is made to a product is
generated, which enhances adhesion property with chemical solution
or resins.
Comparative Example 1
[0277] When the solid-phase polymerization was carried out in the
same manner as Example 1 except that the inorganic particle (A) was
solely used as an oil agent for solid-phase polymerization, and the
phosphate-based compound (B) was not used, the fibers fused each
other and fibrils occurred many times at the time of unwinding,
which led to yarn breakage, and thus steps subsequent to the
cleaning step could not be carried out.
Comparative Example 2
[0278] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that a spinning oil
agent with polyethylene glycol laurate as a main component, instead
of the phosphate-based compound (B), was used as an oil agent for
solid-phase polymerization.
[0279] The characteristics of the obtained fiber are as shown in
Table 7. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was high; and the running tension
fluctuation range (R) was high, a large amount of scum was
accumulated onto yarn supply port and the scum was contaminated
into the product many times and the quality of woven fabric was not
good. Further, yarn breakage also occurred frequently. Presumably,
this was, in addition to yarn breakage ascribed to increased
tension fluctuation by scum accumulation, yarn breakage ascribed to
fibrillation of the fiber which was caused by fusion bonding at the
time of solid-phase polymerization.
[0280] The fiber that was obtained in Comparative Example 2
exhibited a Tm.sub.1 of 332.degree. C., a .DELTA.Hm.sub.1 of 0.7
J/g, a half width of peak at Tm.sub.1 of 25.degree. C., and an
amount of scum generated of 0.0110 g.
[0281] From the above results, it is predicted not only that, also
in practical warping and weaving steps, a large amount of scum is
generated; the running tension fluctuation increases; and yarn
breakage occurs; but also that troubles occur frequently when it is
made to a mesh woven fabric for a screen gauze for printing, a
filter or the like.
Comparative Example 3
[0282] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the inorganic
particle (A) was not used as an oil agent for solid-phase
polymerization.
[0283] In the obtained fiber, generation of fibrils was recognized.
Presumably, this is because the inorganic particle (A) was not used
as the solid-phase polymerization oil agent and thus fusion bonding
was occurred among the fibers. The characteristics of the obtained
fiber are as shown in Table 7. Because the oil adhesion rate of
residual solid-phase polymerization oil agent was high; and the
running tension fluctuation range (R) was high, a large amount of
scum was accumulated onto yarn supply port; yarn breakage that was
apparently ascribed to scum and fibrils occurred many times; and
the weaving was thus discontinued.
[0284] The fiber that was obtained in Comparative Example 3
exhibited a Tm.sub.1 of 335.degree. C., a .DELTA.Hm.sub.1 of 0.6
J/g, a half width of peak at Tm.sub.1 of 24.degree. C., and an
amount of scum generated of 0.0113 g.
[0285] From the above results, it is predicted that a large amount
of scum is generated and yarn breakage ascribed to scum and fibrils
occurs also in practical warping and weaving steps; and thus the
weaving is impossible.
Comparative Example 4
[0286] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that, instead of the
inorganic particles (A) and phosphate-based compound (B), an oil
agent with polydimethylsiloxane (hereinafter PDMS) as a main
component was used as the oil agent for solid-phase
polymerization.
[0287] The characteristics of the obtained fiber are as shown in
Table 7. Although the amount of remaining solid-phase
polymerization oil agent is mathematically small, running tension
fluctuation was high and a very small amount of scum accumulation
on the yarn supply port was observed during the weaving. This
apparently caused increase in running tension and contamination of
scum into the product. In addition, yarn breakage that was
apparently caused by tension fluctuation occurred many times. From
results of scanning electron microscopy for the surface of the
liquid crystalline polyester fiber, irregularity which seems to
come from gelled products of PDMS was observed. Also from results
of IR measurement of scum components adhered to the yarn supply
port at the time of weaving evaluation, gelled products derived
from PDMS were found to adhere on the fiber. That is, PDMS gelled
at the time of the solid-phase polymerization and this gelled
product remained on the fiber after the cleaning step, which
presumably caused tension fluctuation.
[0288] The fiber that was obtained in Comparative Example 4
exhibited a Tm.sub.1 of 336.degree. C., a .DELTA.Hm.sub.1 of 0.7
J/g, a half width of peak at Tm.sub.1 of 27.degree. C., and an
amount of scum generated of 0.0025 g.
[0289] From the above results, increase in tension fluctuation is
facilitated; in addition to weavability defects caused by
occurrence of yarn breakage by tension fluctuation at the time of
warping and generation of tension unevenness or yarn breakage at
the time of weaving, contamination of the scum into the product
takes place.
Comparative Example 5
[0290] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 1 except that the rotation
number of an oiling roller at the time of the addition of the
finishing oil agent was altered and the oil adhesion rate of the
finishing oil agent was altered and the oil adhesion rate of the
fiber was set to 3.2 wt %.
[0291] The characteristics of the obtained fiber are as shown in
Table 7. Because the oil adhesion rate of residual solid-phase
polymerization oil agent was very low and the running tension
fluctuation range (R) was small, the scum generation and tension
fluctuation were suppressed and the process passability and quality
of woven fabric were excellent. However, machine stopping caused by
yarn breakage ascribed to pseudo adhesion of fibers occurred
frequently, and the weaving was thus discontinued.
[0292] The fiber that was obtained in Comparative Example 5
exhibited a Tm.sub.1 of 333.degree. C., a .DELTA.Hm.sub.1 of 0.8
J/g, a half width of peak at Tm.sub.1 of 29.degree. C., and an
amount of scum generated of 0.0012 g.
[0293] From the above results, it is predicted that, although the
effect of suppressing the scum is prominent also in practical
warping and weaving steps, fibers falsely adhere each other due to
a high oil adhesion rate and thus yarn breakage occurs many times;
and the weaving is impossible.
TABLE-US-00007 TABLE 7 Reference Comparative Comparative
Comparative Comparative Comparative Example 3 Example 1 Example 2
Example 3 Example 4 Example 5 Liquid crystalline polyesterpolymer
-- Reference Reference Reference Reference Reference Reference
Example 1 Example 1 Example 1 Example 1 Example 1 Example 1
Inorganic particle (A) -- Talc 1 Talc 1 Talc 1 -- -- Talc 1 Median
diameter (D50) .mu.m 1.0 1.0 1.0 -- -- 1.0 Phosphate-based compound
(B) -- Phosphate-based -- Spinning Phosphate-based PDMS
Phosphate-based compound (B.sub.1) oil agent compound (B.sub.1)
compound (B.sub.1) Oil adhesion rate of solid-phase wt % 15 2.2 4.3
4.1 6.5 15 polymerization oil agent (a + b) a wt % 2.1 2.2 0.6 0.0
0.0 2.1 b/a -- 6 0 6 -- -- 6 The presence of cleaning step --
Absent -- Present Present Present Present The presence of high
tempature -- Present -- Present Present Present Present heat
treatment step The number of filaments Filaments 1 1 1 1 1 1 Single
fiber fineness dtex 6.0 6.0 6.0 6.0 6.0 6.0 Strength cN/dtex 17.9
-- 16.5 16.6 17.2 17.6 Elongation % 2.8 -- 2.3 2.5 2.6 2.7 Elastic
modulus cN/dtex 754 -- 638 679 739 714 The presence of particulates
in -- Absent -- Absent Absent Absent Absent finishing oil agent Oil
adhesion rate % 8.1 -- 2.3 3.0 0.9 3.2 Oil adhesion rate of
residual solid- % 7.3 -- 1.3 2.1 0.1 0.1 phase polymerization oil
agent Oil adhesion rate of finishing oil % 0.8 -- 1.0 0.9 0.8 3.1
agent Running tension fluctuation range cN 5.1 -- 12.1 5.2 11.3 4.9
(R) Process passability -- B -- C C C A Weavabiliy -- C -- C C C C
(11 times) (11 times) (15 times) (12 times) (15 times) Quality of
woven fabric -- C -- C -- B -- (12) (15) (6)
[0294] In the examples below, with the assumption of post
processing in multifilament applications in particular, an effect
of suppressing fusion bonding, running stability, and
post-processability were evaluated as characteristic evaluation of
the liquid crystalline polyester fiber after the solid-phase
polymerization.
Example 26
[0295] Using the liquid crystalline polyester of Reference Example
1, vacuum drying was carried out at 160.degree. C. for 12 hours and
it was then melt extruded by a double-screw extruder of .PHI.15 mm
manufactured by Technovel Corporation, and the polymer was supplied
to a spinning pack while metered by a gear pump. In the spinning
pack, the polymer was filtered using a metal nonwoven fabric
filter, and the polymer was discharged in conditions described in
Table 8. The introduction hole positioned immediately above the die
hole was a straight hole, and a connecting portion between the
introduction hole and the die hole was formed in a taper shape. The
discharged polymer was passed through a heat retaining region of 40
mm, and then cooled and solidified from the outer side of the yarn
by an annular cooling air with 25.degree. C. air flow. Thereafter,
a spinning oil agent whose main component was a fatty acid ester
compound was added, and all of the filaments were together wound to
a first godet roller at a spinning speed described in Table 8. This
was passed through a second godet having the same speed and then
wound in a pirn form via a dancer arm using a pirn winder (EFT type
take up winder manufactured by Kamitsu Seisakusho Ltd., no contact
roller contacting with a wound package). During the winding, no
yarn breakage occurred and the yarn formation property was good.
The characteristics of the obtained spun fiber are shown in Table
8.
TABLE-US-00008 TABLE 8 Example 26 Example 34 Example 35 Example 36
Example 37 Example 38 Liquid crystalline polyesterpolymer Reference
Reference Reference Reference Reference Reference Example 1 Example
2 Example 1 Example 1 Example 1 Example 1 Mole spinning Spinning
temperature .degree. C. 340 325 340 345 345 345 condition Discharge
flow g/min 100.2 100.2 56.0 2.6 150.0 2.4 Hole diameter of die mm
0.13 0.20 0.13 0.13 0.28 0.13 Land length mm 0.26 0.30 0.26 0.26
0.50 0.26 L/D -- 2.0 1.5 2.0 2.0 1.8 2.0 The number of holes 300
300 72 5 192 4 Spinning speed m/min 600 600 1000 1200 500 1000
Spinning draft -- 29 68 20 36 47 27 Characteristics Molecular
weight -- 10.3 .times. 10.sup.4 8.8 .times. 10.sup.4 10.2 .times.
10.sup.4 10 .times. 10.sup.4 10.3 .times. 10.sup.4 10.2 .times.
10.sup.4 of spun fiber Total fineness dtex 1670 1670 560 22 3000 6
The number of filaments Filaments 300 300 72 5 192 1 Single fiber
fineness dtex 5.6 5.6 7.8 4.4 15.6 6.0 Strength cN/dtex 6.5 8.8 6.3
6.7 5.9 6.4 Elongation % 1.5 2.0 1.5 1.5 1.4 1.5 Elastic modulus
cN/dtex 550 543 554 578 524 531 Tm.sub.1 .degree. C. 299 285 298
298 297 297 .DELTA.Hm.sub.1 J/g 2.4 3.1 2.6 2.5 2.5 2.6 Half width
of peak of at .degree. C. 38 43 40 37 39 41 Tm.sub.1
[0296] The fibers were wound back from this spun fiber package
using an SSP-MV type rewinder (contact length (winding stroke of
the innermost layer) of 200 mm, the number of winding of 8.7, taper
angle of 45.degree.) manufactured by Kamitsu Seisakusho Ltd. The
spun fibers are unwound in a vertical direction (in a direction
perpendicular to the fiber rounding direction). Without using a
speed-regulating roller, using an oiling roller (having a
stainless-steel roll with pear skin-finished surface), solid-phase
polymerization oil agent was fed, wherein SG-2000 (manufactured by
Nippon Talc Co., Ltd.) shown as Talc 1 in Table 9, as an inorganic
particle (A), was dispersed into aqueous solution containing 6.0 wt
% phosphate-based compound (B.sub.1) represented by the following
chemical formula (4) as the phosphate-based compound (B) in the
amount of 1.0 wt %. A stainless-steel bobbin with holes and wound
thereon with a Kevlar felt (weight: 280 g/m.sup.2, thickness: 1.5
mm) was used as a core member for the winding back, and the surface
pressure was set to 100 gf (98.0665 cN). The oil adhesion rate of
the solid-phase polymerization oil agent to the fiber after the
winding back and winding back condition are shown in Table 9.
[0297] Next, the bobbin with holes was detached from the package
wound back, and solid-phase polymerization was carried out in a
condition of a package where the fibers were taken up on the Kevlar
felt. The solid-phase polymerization was carried out using a closed
type oven at a condition where the temperature was elevated from a
room temperature to 240.degree. C. over about 30 minutes, kept at
240.degree. C. for 3 hours, elevated to maximum achieving
temperature shown in Table 9 at a rate of 4.degree. C./hr, and kept
for a period of holding time shown in Table 9. As the atmosphere,
dehumidified nitrogen was supplied at a flow rate of 20 NL/min, and
it was discharged from an exhaust port so as not to pressurize the
inside.
[0298] The package after the solid-phase polymerization was
attached to a free roll creel (which had an axis, bearings and a
freely-rotatable outer layer and which had no brakes and no drive
source), and therefrom a yarn was drawn out in a lateral direction
(in a fiber rounding direction), rolled on a first roller with
separate roller rotating at 400 m/min by 6 rounds and taken up by
an EFT type bobbin traverse winder (manufactured by Kamitsu
Seisakusho Ltd.). The characteristics of the obtained fiber after
the solid-phase polymerization are shown in Table 9.
[0299] The results of characteristic evaluation of the obtained
fiber are also shown in Table 9. It is proven that all of the
effect of suppressing fusion bonding, running stability, and
post-processability are excellent.
TABLE-US-00009 TABLE 9 Example 26 Example 27 Example 28 Example 29
Example 30 Example 31 Example 32 Example 33 Spun fiber Example 26
Example 26 Example 26 Example 26 Example 26 Example 26 Example 26
Example 26 Oil agent for solid-phase Inorganic particle (A) -- Talc
1 Talc 1 Talc 1 Silica Talc 2 Talc 1 Talc 1 Talc 1 polymerization
Median diameter (D50) .mu.m 1.0 1.0 1.0 2.7 7.0 1.0 1.0 1.0
Phosphate-based compound (B)or other oil agent -- B.sub.1 B.sub.1
B.sub.1 B.sub.1 B.sub.1 B.sub.1 B.sub.2 B.sub.3 Oil adhesion rate
of solid-phase wt % 15 2.1 30 15 15 15 15 15 polymerization oil
agent (a + b) a wt % 2.1 0.3 4.3 2.1 2.1 5.0 2.1 2.1 b/a -- 6.0 6.0
6.0 6.0 6.0 2.0 6.0 6.0 Winding back Winding back speed m/mm 400
400 400 400 400 400 400 400 condition Winding tension cN/dtex 0.02
0.02 0.02 0.02 0.02 0.02 0.02 0.02 Winding density g/cc 0.8 0.8 0.8
0.8 0.8 0.8 0.8 0.8 Winding volume m 3.2 .times. 10.sup.4 3.2
.times. 10.sup.4 3.2 .times. 10.sup.4 3.2 .times. 10.sup.4 3.2
.times. 10.sup.4 3.2 .times. 10.sup.4 3.2 .times. 10.sup.4 3.2
.times. 10.sup.4 Winding volume kg 6.1 5.5 6.9 6.1 6.1 6.1 6.1 6.1
Solid-phase Maximum achieving .degree. C. 290 290 290 290 290 290
290 290 polymerization temperature Holding time at hr 15 15 15 15
15 15 15 15 maximum achieving temperature Characteristics of fiber
after Molecular weight -- 38.1 .times. 10.sup.4 38 .times. 10.sup.4
38.3 .times. 10.sup.4 38.2 .times. 10.sup.4 38.3 .times. 10.sup.4
38.1 .times. 10.sup.4 36.4 .times. 10.sup.4 41.1 .times. 10.sup.4
olid-phase polymerization Total fineness dtex 1804 1695 1921 1790
1755 1787 1834 1800 The number of filaments Filaments 300 300 300
300 300 300 300 300 Single fiber fineness dtex 6.0 5.7 6.4 6.0 5.9
6.0 6.1 6.0 Strength cN/dtex 20.4 20.1 20.2 20.3 19.7 20.4 19.5
21.7 Elongation % 2.6 2.3 2.6 2.6 2.5 2.5 2.3 2.8 Elastic modulus
cN/dtex 922 865 904 920 882 902 867 955 Tm.sub.1 .degree. C. 331
330 330 332 331 332 330 333 .DELTA.Hm.sub.1 J/g 8.3 8.3 8.5 8.2 8.2
8.3 8.0 8.8 Half width of peak of at Tm.sub.1 .degree. C. 12 11 13
11 12 11 12 10 Adhesion amount relative to total fineness wt % 8.0
1.5 15.0 7.2 5.1 7.0 9.8 7.8 Characteristic Effect of suppressing
fusion bonding -- A B A A B A A B evaluation (The number of times
of fluffs) (0) (2) (0) (0) (1) (0) (0) (2) Running stability -- A B
A B B A A B (The number of times of yarn swinging) (0 times)
(Twice) (0 times) (Once) (Once) (0 times) (0 times) (Twice)
Post-processability -- A B B A A B B A (The number of times of
adhered substances) (1) (6) (4) (1) (1) (3) (4) (1)
Examples 27 and 28
[0300] Effects of the adhesion rate of oil agent for solid-phase
polymerization were evaluated here.
[0301] A spun fiber was obtained by carrying out melt spinning in
the same manner as described in Example 26 and a liquid crystalline
polyester fiber was obtained by carrying out the winding back and
solid-phase polymerization in the same manner as described in
Example 26 except that the rotation number of the oiling roller at
the time of the winding back was altered and the adhesion rate of
the solid-phase polymerization oil agent was altered as shown in
Table 9. The characteristics of the obtained fiber after the
solid-phase polymerization are shown in Table 9.
[0302] The results of characteristic evaluation of the obtained
fiber are also shown in Table 9. It is proven that, although all of
the effect of suppressing fusion bonding, running stability, and
post-processability are excellent, the effect of suppressing fusion
bonding, running stability, and post-processability are slightly
inferior in Example 27 because the adhesion amount is low; and the
post-processability is slightly inferior in Example 28 because the
adhesion amount is high.
Examples 29 and 30
[0303] Effects of the inorganic particle (A) were evaluated
here.
[0304] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 26 except that Sylisia 310P
(manufactured by Fuji Silysia Chemical Ltd.) which was silica was
used as the inorganic particle (A) (Example 29). Further, a liquid
crystalline polyester fiber was obtained in the same manner as
described in Example 26 except that "MICRO ACE" (registered
trademark) P-2 (manufactured by Nippon Talc Co., Ltd.) which was a
talc shown as Talc 2 in Table 9 was used as the inorganic particle
(A). The characteristics of the obtained fiber after the
solid-phase polymerization are shown in Table 9.
[0305] The results of characteristic evaluation of the obtained
fiber are also shown in Table 9. It is proven that, although all of
the effect of suppressing fusion bonding, running stability, and
post-processability are excellent, the effect of suppressing fusion
bonding, running stability, and post-processability deteriorate as
the median diameter become larger.
Example 31
[0306] Effects of the weight ratio between the inorganic particle
(A) and phosphate-based compound (B) were evaluated here.
[0307] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 26 except that the amount of
dispersion of the inorganic particle (A) in the solid-phase
polymerization oil agent and the adhesion rate (a) of the inorganic
particle to the fiber was altered as shown in Table 9. The
characteristics of the obtained fiber after the solid-phase
polymerization are shown in Table 9.
[0308] The results of characteristic evaluation of the obtained
fiber are also shown in Table 9. It is proven that, although all of
the effect of suppressing fusion bonding, running stability, and
post-processability are excellent, the post-processability slightly
deteriorates when (b/a) is small.
Examples 32 and 33
[0309] Effects of the phosphate-based compound (B) were evaluated
here.
[0310] A liquid crystalline polyester fiber was obtained in the
same manner as described in Example 26 except that the
phosphate-based compound (B) was altered to a phosphate-based
compound (B.sub.2) represented by the following chemical formula
(5) or a phosphate-based compound (B.sub.3) represented by the
following chemical formula (6). The characteristics of the obtained
fiber after the solid-phase polymerization are shown in Table 9. As
proven from numerical values including the molecular weight, the
solid-phase polymerization tends not to proceed to a certain extent
in B.sub.2 and tends to proceed in B.sub.3.
[0311] The results of characteristic evaluation of the obtained
fiber are also shown in Table 9. It is proven that, although all of
the effect of suppressing fusion bonding, running stability, and
post-processability are excellent, the post-processability is
slightly inferior in B.sub.2 possibly because it has a number of
hydrocarbon groups containing oxygen atoms; and the
post-processability and running stability are slightly inferior in
B.sub.3 possible because it has a number of potassium atoms and
thus the solid-phase polymerization proceeds.
Comparative Examples 6 to 9
[0312] Effects of the combination use of the inorganic particle (A)
and phosphate-based compound (B) were evaluated here.
[0313] In Comparative Example 6, When the solid-phase
polymerization was carried out in the same manner as Example 26
except that the inorganic particle (A) was solely used as an oil
agent for solid-phase polymerization, and the phosphate-based
compound (B) was not used, the fibers fused each other and fibrils
occurred many times at the time of unwinding, and thereby the fiber
after solid-phase polymerization could not be obtained. From this,
it is proven that the effect is suppressing fusion bonding is not
insufficient with the inorganic particle alone.
[0314] A liquid crystalline polyester fiber was obtained in the
same manner as described in Examples 26 except that an aqueous PDMS
dispersion liquid, instead of the phosphate-based compound (B), was
used as the oil agent for solid-phase polymerization in Comparative
Example 7; the inorganic particle was not used and the
phosphate-based compound was solely used in Comparative Example 8;
a PDMS dispersion liquid was solely used in Comparative Example 9;
and the rotation number of the oiling roller was adjusted and the
adhesion amount of solid-phase polymerization oil agent was altered
as shown in Table 10 in each of the Examples. The characteristics
of the obtained fiber after the solid-phase polymerization are
shown in Table 10.
[0315] The results of characteristic evaluation of the obtained
fiber are also shown in Table 10. In Comparative Example 7, it is
proven that, although an excellent effect of suppressing fusion
bonding was exhibited by combination used of the inorganic particle
and PDMS, there are a number of adhered substances on the fiber
surface and the post-processability is inferior. Further, in
Comparative Example 8, it is proven that the effect of suppressing
fusion bonding and running stability are inferior because the
phosphate-based compound is solely used. In Comparative Example 9,
it is proven that with PDMS being solely used, the running
stability and post-processability are inferior.
Examples 34 to 38
[0316] Effects of the spun fiber were evaluated here.
[0317] A spun fiber was obtained by carrying out melt spinning by
the same method as described in Example 26 except that the spinning
conditions including the liquid crystalline polyester polymer and
spinning temperature were altered as shown in Table 8. In Example
38, among yarns discharged from the die with 4 holes, only one yarn
was taken up and the remaining were sucked by the suction gun to
remove. The characteristics of the obtained fibers are also shown
together in Table 8. In Example 34 where the polymer of Comparative
Example 2 was used and in Example 36 where the spinning was carried
out with a single-yarn fineness of 4.4 dtex, yarn breakage occurred
during the spinning.
[0318] Using the obtained spun fiber, the winding back and
solid-phase polymerization were carried out by the same manner as
Example 26 except that the winding back condition and solid-phase
polymerization condition were altered as shown in Table 10. In
Example 37, three of the spun fibers were twisted together and
wound back. The characteristics of the obtained fiber after the
solid-phase polymerization are shown in Table 10.
[0319] The results of characteristic evaluation of the obtained
fiber are also shown in Table 10. It is proven that, although the
effect of suppressing fusion bonding, running stability, and
post-processability vary in the different types of the spun fiber,
all of them are excellent.
TABLE-US-00010 TABLE 10 Comparative Comparative Comparative
Comparative Example Example Example Example Example Example 6
Example 7 Example 8 Example 9 34 35 36 37 38 Spun fiber Example
Example Example Example Example Example Example Example Example 26
26 26 26 34 35 36 37 38 Oil agent for solid-phase Inorganic
particle (A) -- Talc 1 Talc 1 -- -- Talc 1 Talc 1 Talc 1 Talc 1
Talc 1 polymerization Median diameter (D50) .mu.m 1.0 1.0 -- -- 1.0
1.0 1.0 1.0 1.0 Phosphate-based compound -- -- PDMS B.sub.1 PMDS
B.sub.1 B.sub.1 B.sub.1 B.sub.1 B.sub.1 (B)or other oil agents. Oil
adhesion rate of solid- wt % 2.1 4.3 4.1 6.5 15 15 15 15 15 phase
polymerization oil a wt % 2.1 0.6 0.0 0.0 2.1 2.1 2.1 2.1 2.1 b/a
-- 0.0 6.0 -- -- 6.0 6.0 6.0 6.0 6.0 Winding back Winding back
speed m/mm 400 400 400 400 400 400 300 200 300 condition Winding
tension cN/dtex 0.02 0.02 0.02 0.02 0.02 0.04 0.23 0.04 0.16
Winding density g/cc 0.8 0.8 0.8 0.8 0.8 1.0 0.6 0.9 0.5 Winding
volume m 3.2 .times. 10.sup.6 3.2 .times. 10.sup.4 3.2 .times.
10.sup.4 3.2 .times. 10.sup.4 3.2 .times. 10.sup.4 6.4 .times.
10.sup.4 10.9 .times. 10.sup.4 1.2 .times. 10.sup.4 43.2 .times.
10.sup.4 Winding volume kg 5.5 5.6 5.6 5.7 6.1 4.1 0.3 12.4 0.3
Solid-phase Maximum achieving .degree. C. 290 290 290 290 290 290
285 300 290 polymerization temperature Holding time at maximum hr
15 15 15 15 15 15 15 20 15 achieving temperature Characteristics of
fiber after olid-phase Molecular weight -- Unable to evaluate 38.2
.times. 10.sup.4 38.1 .times. 10.sup.4 38.2 .times. 10.sup.4 36.2
.times. 10.sup.4 37.1 .times. 10.sup.4 38.5 .times. 10.sup.4 35.4
.times. 10.sup.4 38.8 .times. 10.sup.4 polymerization Total
fineness dtex due to occurrence of 1733 1717 1723 1805 603 24 9648
6 The number of filaments Filaments fusion bonding 300 300 300 300
72 5 576 1 Single fiber fineness dtex 5.8 5.7 5.7 6.0 8.4 4.8 16.8
6.4 Strength cN/dtex 20.3 18.4 20.1 21.1 20.2 22.4 17.8 22.1
Elongation % 2.5 2.2 2.5 2.8 2.6 2.7 2.2 2.7 Elastic modulus
cN/dtex 895 815 915 795 901 1011 807 965 Tm.sub.1 .degree. C. 332
330 332 319 332 333 330 332 .DELTA.Hm.sub.1 J/g 8.2 8.4 8.2 10.1
8.0 9.2 7.9 8.9 Half width of peak of at Tm.sub.1 .degree. C. 11 10
12 7 13 9 13 11 Adhesion amount relative to wt % 3.8 2.8 3.2 8.1
7.7 8.8 7.2 6.8 total fineness Characteristic evaluation Effect of
suppressing fusion -- A (0) C (10) B (2) B (2) A (0) B (1) A (0) B
(1) bonding (The number of times of Running stability -- B C C B A
A A A (The number of times of (Twice) (32 times) (20 times) (Twice)
(0 times) (0 times) (0 times) (0 times) yarn swinging)
Post-processability -- C (15) B (4) C (13) B (5) A (2) A (1) B (8)
A (0) (The number of times of adhered substances) Note) PDMS:
polydimethylsilonane
INDUSTRIAL APPLICATIONS OF THE INVENTION
[0320] A liquid crystalline polyester fiber of the present
invention and a method of producing the liquid crystalline
polyester fiber are suitable in particular for uses of filters or
screen gauzes that are high-mesh woven fabrics.
* * * * *