JP5226720B2 - Water-absorbing wholly aromatic polyester fiber - Google Patents

Description

  The present invention relates to a wholly aromatic polyester fiber having high water absorption, wear resistance, and excellent processability.

  High-strength and high-modulus fibers are used as tension members for optical cables, but recently, when water-absorbing polymers are attached to the fibers and water enters the optical cables, water is diffused in the vertical direction by capillary action. High-strength and high-modulus fibers with a function of stopping are often used.

  Examples of the high-strength and high-modulus fiber as described above include a fiber coated with a water-blocking material containing a highly water-absorbent resin having a particle size of less than 100 microns, a high swelling agent, and a dispersion liquid such as oil. (For example, refer to Patent Document 1). However, in the method as described in Patent Document 1, a pulverization step of the superabsorbent resin is necessary, and in many cases it falls off during the processing step because it adheres to the fiber surface in the form of particles, There are problems such as difficulty in uniformly adhering to the fibers, easy adhesion spots, and poor wear resistance.

  Moreover, the fiber which made the super water-absorbent resin contain in the water in a water-in-oil emulsion, and to which the resin was made to adhere is disclosed (for example, refer patent documents 2-3). However, these methods are not easy to remove oil, and an explosion-proof facility must be used at the time of oil removal, and the facility becomes excessive and inferior in safety. In addition, these high-strength and high-modulus fibers described in Patent Documents 1 to 3 correspond to wholly aromatic polyamide fibers such as aramid, but wholly aromatic polyamide fibers such as aramid are absorbed by the highly water-absorbent resin. There was a problem that the strength was lowered and the wear resistance was poor.

Special table 2003-528986 gazette JP-A-4-263670 JP 7-504463 A

  An object of the present invention is to provide a high-strength and high-elastic modulus fiber that has high water absorption, excellent processing process passability, and abrasion resistance, and that does not cause a decrease in strength even after the high water-absorbent resin absorbs water. Is.

  As a result of intensive studies to solve the above problems, the present inventors have coated a superabsorbent resin and a specific silicon-based swelling agent in a film form on at least a part of the surface of the wholly aromatic polyester fiber. The resulting fiber is highly water-absorbing and excellent in abrasion resistance, and does not cause a decrease in strength even after the water-absorbing resin absorbs water, and a high-strength and high-modulus fiber having good processability can be obtained. I found out.

  That is, the present invention is a wholly aromatic polyester fiber in which at least a part of the fiber surface is coated with a superabsorbent resin and an organopolysiloxane in the form of a film. Preferably, the superabsorbent resin is partially or entirely polyacrylic acid. Further, the above-mentioned wholly aromatic polyester fiber is a cross-linked product neutralized with an organopolysiloxane having a degree of polymerization of 50,000 to 200,000.

  In addition, the present invention provides a polyacrylic acid partially or wholly neutralized compound, an polyethyleneimine aqueous solution, an organopolysiloxane and an aqueous solution comprising a surfactant, which are attached to a wholly aromatic polyester fiber, dried, and then heated. It is related with the manufacturing method of said wholly aromatic polyester fiber which provides water absorption by making it bridge | crosslink.

  According to the present invention, since the superabsorbent resin and the organopolysiloxane are coated on the surface of the wholly aromatic polyester fiber in a film shape, the wear resistance is excellent, and even after the superabsorbent resin absorbs water, Compared to wholly aromatic polyamide fibers such as aramid, which is a high-strength and high-modulus fiber, it does not cause a decrease in strength, so it exhibits excellent effects when used as a tension member for optical cables.

  Hereinafter, the present invention will be described in detail. Typical high-strength and high-modulus fibers include wholly aromatic polyamide fibers (so-called aramid fibers) and wholly aromatic polyester fibers (so-called polyarylate fibers). In addition to the features such as high strength and high elasticity, it is necessary because it has features such as low hygroscopicity, excellent wear resistance, difficult to cut, and excellent shock absorption.

  The wholly aromatic polyester fiber referred to in the present invention is an aromatic polyester or an aromatic polyester amide exhibiting optical anisotropy (liquid crystallinity) in the melt phase. For example, a sample is placed on a hot stage and raised in a nitrogen atmosphere. It can be recognized by heating and observing the transmitted light of the sample.

  The wholly aromatic polyester used in the present invention is composed mainly of a repeating structural unit of aromatic diol, aromatic dicarboxylic acid or aromatic hydroxycarboxylic acid, or a repeating structural unit obtained by adding aromatic hydroxyamine to the above structural unit. And wholly aromatic polyester amides.

  In addition, the aromatic polyester used in the present invention contains other aromatic, alicyclic, aliphatic diol, dicarboxylic acid, hydroxycarboxylic acid, diamine, hydroxyamine, etc. to such an extent that the effects of the present invention are not impaired. May be included. Specific examples include isophthalic acid, naphthalenedicarboxylic acid, dioxynaphthalene, benzenediamine, and the like. However, if these monomers exceed 10 mol%, the effect of the present invention may be impaired.

  The melting point (Tm) of the wholly aromatic polyester used in the present invention is preferably 260 to 380 ° C, and more preferably 270 to 350 ° C. The melting point here is the peak top temperature of the main endothermic peak observed with a differential scanning calorimeter (DSC: for example, TA3000 manufactured by METTLER) based on the JIS K7121 test method.

A preferred example of the wholly aromatic polyester polymer used in the present invention is a polymer composed of repeating structural units represented by the following chemical formulas 1 (P) and (Q).
More preferably, the following [A], [B], [C], [D], and [E] are composed of 90 mol% or more of a repeating unit, and [A]: [B]: [C] : [D]: [E] = 100: 1 to 20: 5 to 100: 2 to 80: 2 to 20: A fiber composed of a wholly aromatic polyester amide having a molar ratio of 80: 2 to 20.

The wholly aromatic polyester fiber of the present invention can be obtained by melt spinning a polymer by a conventional method. The spinning temperature is 10 ° C. or more higher than the melting point of the aromatic polyester (and within a temperature range in which a molten liquid crystal is formed). Thus, it is preferable to perform spinning under conditions of a shear rate of 10 ³ sec ⁻¹ or more and a spinning draft of 20 or more. By spinning at such a shear rate and a spinning draft, the orientation of the molecules proceeds and performance such as excellent strength can be obtained. The shear rate (γ) is calculated by r = 4Q / πr ³ where r (cm) is the nozzle radius and Q (cm ³ / sec) is the polymer per single hole and the discharge amount. When the nozzle cross section is not a circle, the radius of a circle having an area equivalent to the cross-sectional area is defined as r.

  In order to improve strength, elastic modulus, wear resistance, fatigue resistance, and the like, it is necessary to heat-treat and / or stretch-heat the spinning raw yarn. The heat treatment may be performed only in an inert atmosphere, or may be performed in an active atmosphere in the middle. In addition, under inert atmosphere means in inert gas, such as nitrogen and argon, or under reduced pressure, and means that active gas, such as oxygen, is 0.1 volume% or less. The term “in an active atmosphere” refers to an atmosphere containing 1% by volume or more of an active gas such as oxygen, preferably 10% by volume or more of an oxygen-containing gas, and air is preferably used in terms of cost. When water is present, the hydrolysis reaction proceeds in parallel, so a dry gas having a dew point of −20 ° C. or lower, preferably −40 ° C. or lower is used.

  A preferable temperature condition for the heat treatment is a temperature range from Tm-35 ° C. to Tm-2 ° C. with respect to the melting point Tm of the polymer before melt spinning, and heating at such a temperature condition results in high strength and A wholly aromatic polyester fiber capable of realizing an elastic modulus can be obtained. Further, the heat treatment may be performed at a constant temperature, or the temperature may be raised sequentially in accordance with the melting point of the fiber that gradually rises by heating. The heat treatment condition can also be expressed by the product of (temperature difference from melting point: ° C.) and (heating time: time) heated per single fiber fineness (dtex), and in this case, 50 ≦ A specific wholly aromatic polyester fiber defined in the present invention can be obtained by a heat treatment of (temperature difference from melting point) × (heating time) / (single fiber fineness) ≦ 100. When heat is supplied by a medium such as gas, there are a method using radiation by a heating plate, an infrared heater, etc., a method in contact with a heat roller, a plate, etc., an internal heating method using high frequency, etc. Depending on the purpose, it can be done under tension or no tension. The shape of the treatment is a casket shape, a cheese shape, a tow shape (for example, by placing on a wire mesh) or a continuous treatment of a roller, and the form of the fiber can be either a filament or a cut fiber. .

  The wholly aromatic polyester fiber of the present invention may contain a thermoplastic polymer such as polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyphenylene sulfide, polyetheresterketone, and fluorine resin as necessary. Additives such as inorganic substances such as titanium oxide, kaolin, silica, barium oxide, carbon black, colorants such as dyes and pigments, antioxidants, ultraviolet absorbers, and light stabilizers may be included.

  In the present invention, it is important that at least a part of the fiber surface of the wholly aromatic polyester fiber is coated with a superabsorbent resin and polysiloxane in the form of a film. When the water-absorbent resin is in the form of particles, it is difficult to uniformly adhere to the fibers, and adhesion spots are likely to occur. Moreover, when the coating form is not a film form, for example, when it adheres to the fiber surface in the form of particles, there is a problem in durability because the particles easily fall off during the processing step.

  The superabsorbent resins used in the present invention include crosslinked and partially neutralized polyacrylic acid, crosslinked and partially neutralized starch acrylic acid graft polymer, crosslinked and partially neutralized. In addition, copolymers of isobutylene and maleic anhydride, saponification products of highly water-absorbent resins of vinyl acetate-acrylic acid copolymers, hydrolysates of acrylamide polymers or acrylamide copolymers, hydrolysates of acrylonitrile copolymers, mixtures thereof, or copolymers thereof Is mentioned. Further, specific examples of the superabsorbent resin include partially or wholly neutralized and partially or wholly crosslinked poly (acrylic acid) derivatives (PACA), partially or wholly crosslinked poly (Sodium or potassium acrylamido-2-methyl-propanesulfonate) derivative (PAMPS), partially or fully crosslinked, poly (chlorotrimethylaminoethyl-acrylate) derivative (PCTA), partially or fully crosslinked, Examples thereof include poly (acrylamide) derivatives (PAAD), mixtures thereof, and copolymers thereof.

  The organopolysiloxane used in the present invention comprises a repeating unit represented by the following formula (I).

(Wherein the X1, X2, X3 and X4, are the same or different and each represents _{-H, -OH, -COOH, -R,} -NH 2, -ROH, -RCOOH, or -RNH _2, R is An alkyl group (for example, a C _1-5 alkyl group such as a methyl group or an ethyl group) or an aryl group (for example, a phenyl group), and m and n represent an integer of 1 or more.

  The organopolysiloxane used in the present invention is preferably a high polymerization degree grade having an average degree of polymerization of 50,000 to 200,000 from the viewpoints of wear resistance and drop-off prevention.

As a method of coating the fibers of the superabsorbent resin, an aqueous solution comprising a partially or wholly neutralized polyacrylic acid precursor of the superabsorbent resin, polyethyleneimine, organopolysiloxane, and a surfactant. Is uniformly adhered to the fiber surface with an oiling nozzle, dried at a temperature of 80 ° C. or higher, and then subjected to a heat treatment for crosslinking. By using the coating method, at least a part of the fiber surface can be coated with a superabsorbent resin and an organopolysiloxane in the form of a film.
When heat treatment is not performed in the coating method, the cross-linking reaction does not proceed, so that the highly water-absorbing fiber targeted by the present invention cannot be obtained.

  As the surfactant used in the coating method, a nonionic, anionic or cationic surfactant may be used. For example, polyoxyethylene alkylphenyl ether, quaternary ammonium salt, sodium alkylbenzene sulfonate and the like can be mentioned. The amount of the surfactant used is suitably about 1 to 50 parts by mass with respect to 100 parts by mass of the polysiloxane.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these at all.

[Strength and elastic modulus]
In accordance with JIS L1013, the breaking strength and elastic modulus (initial tensile resistance) were determined under the conditions of a test length of 20 cm, an initial load of 0.1 g / d, and a tensile speed of 10 cm / min, and an average value of 5 or more points was adopted. .

[Water absorption rate]
About 5 m of a fiber sample was collected, immersed in water for 10 minutes, then centrifuged and dehydrated, and the weight was measured.
Thereafter, it was dried with hot air at 70 ° C. for 4 hours, followed by vacuum drying at 70 ° C. for 2 hours, and the weight was measured after drying. Water absorption rate = {(weight after dehydration−weight after drying) / weight after drying} × 100

[Abrasion resistance]
A single test yarn is twisted 3 times between the reversing pulley and the free roller at the other end without twisting, and attached in an 8-shape. A load of 10 kg is applied to the free roller, and the speed is reversed 105 times / minute. The test yarn is reciprocated by a pulley and worn, and the number of times until cutting is measured.

[Reference Example 1]
<Fiber preparation>
p-acetoxybenzoic acid [A] 60 moles, 6-acetoxy-2-naphthoic acid [B] 4 moles, terephthalic acid [C] 18 moles, 4,4'-bisphenol [D] 14 moles, and p- Melt anisotropic aromatic polyester amide was obtained from 4 mol of aminophenol [E]. The melting point of this polymer was 340 ° C. The polymer was melt-spun from a die having a nozzle diameter of 0.1 mmφ and a number of holes of 200 at a spinning temperature of 360 ° C. and a spinning speed of 1000 m / min to obtain a filament of 1580 dtex / 200 f.
The fiber performance of the obtained spinning yarn is
Strength (DT) = 7.5 cN / dtex
Elongation (DE) = 1.5%
Elastic modulus (YM) = 580 cN / dtex
Met.
The obtained spinning yarn was homogenized at 180 ° C., then heated to 300 ° C. in 4 hours, and heat-treated at 300 ° C. for 8 hours. The fiber performance obtained is strength (DT) = 21.5 cN / dtex
Elongation (DE) = 2.8%
Elastic modulus (YM) = 740 cN / dtex
Met.

[Reference Example 2]
<Preparation of water absorbent resin solution>
(1) Add 962.5 g of water to 30.5 g of sodium hydroxide and dissolve.
(2) 74.5 g of polyacrylic acid (Jurimer AC-10LHPK (manufactured by Toa Chemical Co., Ltd.)) is gradually stirred and dissolved in the solution of (1).
(3) 1.125 g of polyethyleneimine (Epomin SP-200 (manufactured by Nippon Shokubai Co., Ltd.)) is collected and dissolved in 50 g of water.
(4) The solution of (3) above is added to the solution of (2) above while gradually stirring and stirred until uniform. The solution after stirring is a solution having a concentration of about 9% by mass.

[Reference Example 3]
<Preparation of aqueous organopolysiloxane solution>
An organosilicon emulsion aqueous solution (Matsumoto Yushi Seiyaku Co., Ltd. Silicon Softener 318) having a polymerization degree of 100,000 was diluted to prepare a 12% solution.

[Reference Example 4]
<Applying water absorbent resin to fiber>
The fiber 1580 dtex / 200f obtained in Reference Example 1 was untwisted and unwound at 20 m / min, and adhered to the oiling nozzle while measuring the mixture of the water-absorbent resin solution and the organosilicon aqueous solution to a predetermined adhesion amount. Then, drying was performed in a hot air oven at 120 ° C. over 18 seconds, and heat treatment was continuously performed in a hot air oven at 200 ° C.

[Example 1]
The fiber obtained in Reference Example 1 was applied so that the water-absorbent resin of Reference Example 2 was 2.5% by mass and the organopolysiloxane of Reference Example 3 was 1.0% by mass. And dried and heat-treated. The results are shown in Table 1.

[Example 2]
The fiber obtained in Reference Example 1 was applied so that the water-absorbent resin of Reference Example 2 was 5.0% by mass and the organopolysiloxane of Reference Example 3 was 1.0% by mass. And dried and heat-treated. The results are shown in Table 1.

[Comparative Example 1]
To the fiber obtained in Reference Example 1, 2.5% by mass of the water-absorbent resin of Reference Example 2 was applied, and on the other hand, the organopolysiloxane of Reference Example 3 was not applied and dried under the conditions of Reference Example 4. A heat treatment was performed. The results are shown in Table 1.

[Comparative Example 2]
The fiber obtained in Reference Example 1 was applied so that the water-absorbent resin of Reference Example 2 was 2.5% by mass and the organopolysiloxane of Reference Example 3 was 1.0% by mass. Only drying was performed. The results are shown in Table 1.

[Comparative Example 3]
To Kevlar T49 (manufactured by Toray DuPont), the water-absorbent resin of Reference Example 2 was applied to 2.5% by mass and the organopolysiloxane of Reference Example 3 to 1.0% by mass, followed by drying and heat treatment. Went. The results are shown in Table 1.

[Comparative Example 4]
Aqua fiber 10SH · NF (Sumitomo Seika Chemicals Co., Ltd .: particle size 20-30 μm) emulsified with an emulsifier mainly composed of an ester oil lubricant is applied to the fiber obtained in Reference Example 1 in an amount of 2.5 mass. %, And dried and heat-treated. The results are shown in Table 1.

[Comparative Example 5]
For the fiber obtained in Reference Example 1, 70 parts by mass of Milox W 45985 (manufactured by Chemische Fabrik Stockhausen GmbH), 10 parts by mass of Span85 (manufactured by ICI Holland BV), and Exxol D80 (manufactured by Exxon Chemical Holland BV). 20 parts by mass was added to 2.5% by mass, followed by drying and heat treatment. The results are shown in Table 1.

As shown in Table 1, the fiber of the present invention has a high water absorption rate, and the fiber strength after water absorption is not lowered as compared with that before water absorption, and thus the durability after water absorption is excellent.
On the other hand, in Comparative Example 1, since the organopolysiloxane was not applied in the process of Reference Example 4, the yarn was taken with the resin fixed to the roller, and the single yarn was broken. Moreover, the obtained fiber was extremely inferior in wear resistance. In Comparative Example 2, since the heat treatment was not performed in the process of Reference Example 4 and only drying was performed, the crosslinking reaction did not occur. Therefore, the water absorption was remarkably low, and the target fiber of the present invention was not obtained.
In Comparative Example 3, since the high-strength / high-modulus fiber was an aramid fiber, a decrease in fiber strength after water absorption was observed. In Comparative Example 4, since the superabsorbent resin was in the form of particles, not only the process passability was poor, but also the wear resistance was remarkably inferior. Comparative Example 5 is a fiber in which a highly water-absorbing resin is contained in water in a water-in-oil emulsion and the resin is adhered, but the abrasion resistance is remarkably inferior.

  According to the present invention, since the superabsorbent resin and the organopolysiloxane are coated on the fiber surface in the form of a film, it has excellent wear resistance, and even after the superabsorbent resin absorbs water, Since it does not cause a decrease in strength compared to a fully aromatic polyamide fiber such as an aramid elastic modulus fiber, it exhibits an excellent effect when used as a tension member of an optical cable.

Claims (4)

  A wholly aromatic polyester fiber in which a superabsorbent resin and an organopolysiloxane are coated in a film shape on at least a part of the fiber surface.   2. The wholly aromatic polyester fiber according to claim 1, wherein the superabsorbent resin comprises a crosslinked product partially or entirely neutralized with polyacrylic acid.   The wholly aromatic polyester fiber according to claim 1 or 2, wherein the organopolysiloxane is an organopolysiloxane having a polymerization degree of 50,000 to 200,000.   By adhering a partially or wholly neutralized polyacrylic acid compound, an aqueous solution of polyethylenimine, an aqueous solution of polysiloxane and a surfactant to a wholly aromatic polyester fiber, drying, and then crosslinking by heating. The manufacturing method of the fully aromatic polyester fiber in any one of Claims 1-3 which provides water absorption.