JP2003003333A - High-strength conjugate fiber and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber which can be produced in an operationally excellent manner from an high-strength high-elastic modules conjugate fiber consisting of a core component of a melt liquid crystal-forming polyester and a sheath component of polyphenylene sulfide while avoiding filament breakage and fibrillation owing to fusion of single yarns to each other occurring during heat treatment. SOLUTION: The high-strength conjugate fiber comprises a core-sheath type conjugate fiber consisting of the core component of a melt liquid crystal-forming polyester and the sheath component of >=10 cN/dtex and Young's modules of >=400 cN/dtex. The sheath component has non-melting property (non-melting at 400 deg.C).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite fiber having a high strength and a high elastic modulus, which is excellent in heat resistance, wear resistance and fatigue resistance, and its field of use is general industrial materials, particularly ropes. , Rubber reinforcement, geotextile, FRC
It is widely used for applications, computer ribbons, base fabrics for printed boards, airbags, bag filters, screen gauze, etc.

[0002]

2. Description of the Related Art Molten liquid crystal-forming polyester fibers have a high strength and a high elastic modulus because their molecular chains are highly oriented in the fiber axis direction as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-174408. It is known. However,
Since only a weak intermolecular force works in the direction perpendicular to the fiber axis, fibrils are easily generated due to friction, which causes a trouble. In addition, a kink band or buckling phenomenon is likely to occur, and it tends to be concentrated in a polar area, so that the fatigue resistance is low. For the purpose of improving these drawbacks, a composite fiber in which an aromatic polyester capable of forming an anisotropic molten phase as a core component and a polyphenylene sulfide as a sheath component is proposed in JP-A 1-229815. Further, Japanese Patent Laid-Open No. 174722/1992 proposes a method for producing a composite fiber in which interfacial peeling is less likely to occur by polymerizing a polyphenylene sulfide resin, washing with an acid, and then spinning the composite with a main chain type liquid crystal resin.

On the other hand, as a method of making a polyphenylene sulfide resin infusible, Japanese Patent Publication No. 60-35370 discloses a method for improving the surface hardness of an article, which is disclosed in JP-A-63-
No. 182413, No. 2-61110, No. 5-209368, No. 5-230712.
Japanese Patent Laid-Open No. 5-230760 and the like disclose methods for producing polyphenylene sulfone fibers, but these patents deal only with fibers having a strength of 3 to 5 g / d at a general level, and composite fibers. The fiber is not explicitly mentioned either.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
As described in Japanese Patent Laid-Open No. 5 and Japanese Patent Application Laid-Open No. 4-174722, by using a core-sheath structure, fibrillation resistance,
It is a fact that the abrasion resistance is improved. Furthermore, although this composite fiber already has sufficient strength and elastic modulus just by spinning, the performance can be further improved by relaxation heat treatment or tension heat treatment. It is known. However, if the relaxation heat treatment or the tension heat treatment is performed at a temperature higher than the softening temperature of the polyphenylene sulfide resin as the sheath component, fusion of the single yarns occurs, and the melted portion is caused by the rewinding of the subsequent process, etc., resulting in yarn breakage, surface peeling, etc. There was a problem that occurs. Furthermore, in combination with a molten liquid crystal-forming polyester having a melting point higher than that of the polyphenylene sulfide resin, solid phase polymerization must be carried out at a temperature at which the polyphenylene sulfide resin does not melt. There was a problem that could not be expressed. Further, as described above, even in the method of making the polyphenylene sulfide non-meltable, only the fibers having a general strength of 3 to 5 g / d are handled, and the composite fibers are also clearly described. However, the present invention, which was insufficient to obtain the high-strength fiber of the present invention, solves the problems at the time of solid-phase polymerization of these conventional conjugate fibers, and has a better process passability than conventional ones. A high-strength composite fiber having

[0005]

That is, the present invention has the following constitution in order to achieve the above object. 1. In a core-sheath type composite fiber in which the core component is a melt-liquid crystal forming polyester and the sheath component is a polyphenylene sulfide resin, the strength of the composite fiber is 10 cN / dtex or more and the Young's modulus is 4
00cN / dtex or more, and the sheath component is non-melting (4
A high-strength composite fiber characterized by being non-melted at 00 ° C. 2. The high-strength composite fiber according to item 1, wherein the composite fiber is a monofilament having a dtex of 20 dtex or less. 3. When the core component is a melt-liquid crystal forming polyester, and the sheath component is a polyphenylene sulfide resin as a raw material to produce a core-sheath type composite fiber, the sheath component is non-meltable (at 400 ° C.) by subjecting the melt-spun composite fiber to an oxidation treatment. A method for producing a high-strength composite fiber, which comprises performing non-melting and solid-phase polymerization. 4. Oxidation treatment is as follows (1)
The method for producing a high-strength conjugate fiber according to claim 3, wherein the treatment is performed with a solution containing at least one of (3) to (3).

(1) Organic peracid (2) Sodium hypochlorite (3) Hydrogen peroxide

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below.

The molten liquid crystal-forming polyester used in the present invention refers to a polyester that exhibits optical anisotropy when heated and melted. This characteristic can be verified by, for example, placing the sample on a hot stage, heating it up in a nitrogen atmosphere, and observing the transmitted light of the sample with a polarizing microscope.

Examples of the melt liquid crystal-forming polyester used in the present invention include: Aromatic oxycarboxylic acid polymer, B.I. A polymer of an aromatic dicarboxylic acid with an aromatic diol or an aliphatic diol, C.I. Examples thereof include copolymers of A and B. A conventionally known method can be used for polymerizing the molten liquid crystal-forming polyester.

Here, as the aromatic oxycarboxylic acid,
Examples thereof include hydroxybenzoic acid and hydroxynaphthoic acid, and alkyl, alkoxy and halogen substitution products of the above aromatic oxycarboxylic acids. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, naphthalenedicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylethanedicarboxylic acid, and the like, or alkyl, alkoxy and halogen substitution products of the aromatic dicarboxylic acid. And so on.

As the aromatic diol, hydroquinone, resorcin, dioxydiphenyl, naphthalene diol, etc., or the above aromatic alkyl, alkoxy,
Examples include halogen-substituted compounds. Examples of the aliphatic diol include ethylene glycol, propylene glycol, butanediol, neopentyl glycol and the like.

In the present invention, polyesters obtained by polymerizing the above-mentioned monomers can be widely used. Preferred examples thereof include those in which a p-hydroxybenzoic acid component and an ethylene terephthalate component are copolymerized, and those in which a p-hydroxybenzoic acid component, 4,4-dihydroxybiphenyl, terephthalic acid and / or isophthalic acid are copolymerized. A copolymer of a p-hydroxybenzoic acid component and a 6-hydroxy-2-naphthoic acid component, a p-hydroxybenzoic acid component and 6-hydroxy-2
-A copolymer of a naphthoic acid component, hydroquinone and terephthalic acid can be used.

The molten liquid crystal-forming polyester used in the present invention preferably has a melting point of 260 to 360 ° C, more preferably 270 to 350 ° C. The melting point was measured by measuring the temperature at which the main endothermic peak observed with a differential scanning calorimeter (DSC manufactured by Perkin Elmer) appears.

The polyphenylene sulfide resin referred to in the present invention is a polymer containing 70 mol% or more, more preferably 90 mol% or more of the repeating constitutional unit represented by the following chemical formula 1. If the repeating unit is less than 70 mol%, the heat resistance is impaired. It is not preferable because

[0015]

[Chemical 1] Polyphenylene sulfide resin is generally disclosed in JP-B-45-
A polymer having a relatively small molecular weight obtained by the production method typified by 3368 and an essentially linear polymer having a relatively high molecular weight obtained by the production method typified by Japanese Patent Publication No. 52-12240. There is the above-mentioned Japanese Patent Publication No. 45-33
The polymer obtained by the method described in Japanese Patent Publication No. 68 may be used after being polymerized to have a high degree of polymerization by heating in an oxygen atmosphere after polymerization or by adding a crosslinking agent such as peroxide and heating. Although it is possible to use PPS obtained by any method in the present invention, as disclosed in JP-A-4-174722 in order to suppress the core-sheath interfacial separation of the core-sheath composite yarn, etc. It is preferable to use a polyphenylene sulfide resin that has been subjected to acid washing.

The core component polymer and the sheath component polymer used in the present invention can be added to the polymer within a range not impairing the effects of the present invention.
Polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyester ether ketone,
A thermoplastic polymer such as a fluorine resin may be added. Inorganic substances such as titanium oxide, kaolin, silica and barium oxide, carbon black, colorants such as dyes and pigments, antioxidants, ultraviolet absorbers and light stabilizers may be added.

The high strength composite fiber of the present invention has a strength of 10 cN / d.
It is important that tex or more and Young's modulus are 400 cN / dtex or more. Strength is less than 10 cN / dtex and Young's modulus is 4
If it is less than 00 cN / dtex, the properties required in the field of using the conjugate fiber of the present invention cannot be satisfied, and the difference from general-purpose fibers becomes small, and the superiority of the high-strength conjugate fiber of the present invention is lost.

Further, it is important that the sheath component of the high-strength composite fiber of the present invention is non-melting. Being non-melting means not only preventing fusion between fibers in heat treatment such as solid-state polymerization but improving process passability and stability, but also the fibers themselves are friction-proof, flame-resistant, and fire-resistant. Since it can be imparted with properties, it can be used as a fiber with a wide range of applications.

In the method for producing the high-strength conjugate fiber of the present invention, the melt-spun conjugate fiber is oxidized in the production of the conjugate fiber whose core component is the molten liquid crystal forming polyester and whose sheath component is the polyphenylene sulfide resin. It is important that the sheath component is made non-melting (non-melting at 400 ° C.) by the treatment and then solid-phase polymerized. In order to avoid single yarn breakage and surface peeling due to fusion between fibers during solid phase polymerization, it is essential to carry out treatment before solid phase polymerization, and the effect is also large.

Further, the method for non-melting the high-strength composite fiber of the present invention is an oxidative treatment, and the oxidative treatment can be carried out with a solution containing at least one of the following (1) to (3). preferable.

(1) Organic peroxide (2) Sodium hypochlorite (3) Hydrogen peroxide As used herein, organic peracid is performic acid, peracetic acid, perbenzoic acid, perbutyric acid, perpropionic acid, Examples include perphthalic acid, m-chloroperbenzoic acid, pertrichloric acid, and pertrichloroacetic acid. Among them, peracetic acid is particularly preferable because of its high reaction rate and easy handling.

Further, the oxidation treatment is preferably a solution treatment, and a continuous treatment in the form of a thread, a batch treatment in a winding package or the like can be used.

The high-strength composite fiber of the present invention can be produced by a known composite spinning machine up to the oxidation treatment. As an example, melted liquid crystal forming polyester and polyphenylene sulfide resin are individually melted by a general composite spinning machine having two extruders, combined with a known core-sheath composite spinneret, and discharged as a composite fiber, and a Godie roller is used. The raw yarn for spinning is manufactured by taking up and winding. The high-strength conjugate fiber of the present invention is produced by subjecting this spun yarn to oxidation treatment with, for example, peracetic acid, and then subjecting it to solid-phase polymerization.

[0024]

The present invention will be described in more detail with reference to the following examples. Each characteristic value in the examples was obtained by the following method.

A. Melting point Melting point is a differential scanning calorimeter (DS made by Perkin Elmer Co., Ltd.
It was carried out by measuring the temperature at which the main endothermic peak observed in C) appeared.

B. Strength and elongation, Young's modulus Strength and elongation, Young's modulus were measured using Tensilon UCT-100 manufactured by Orientec Co., Ltd. according to JIS L1013.

C. Confirm non-melting The melting behavior at 400 ° C. was observed using a melting point microscope.

Example 1 Structural unit (1) produced from p-acetoxybenzoic acid as the core liquid crystalline polyester capable of forming liquid crystals, structural unit (2) produced from 4,4-dihydroxybiphenyl and terephthalic acid, and ethylene glycol. Consisting of the structural unit (3) of polyester produced from terephthalic acid, the structural unit (1) accounts for 80 mol% of the whole, the total of the structural unit (2) and the structural unit (3) accounts for 20 mol%, and the structural unit ( The molar ratio of 2) / (3) is 3/5
Which is a liquid crystal-forming polyester. The melting point of the molten liquid crystal-forming polyester was 315 ° C.

As a polyphenylene sulfide resin as a sheath component, 25 mol of sodium sulfide nonahydrate, 2.5 mol of sodium acetate and N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were charged into an autoclave equipped with a stirrer, and the contents were gradually passed while nitrogen was passed. The temperature was raised to 205 ° C. and water was distilled off. Next, after cooling the reaction vessel to 180 ° C., 25.3 mol of 1,4-dichlorobenzene and NMP were added, the mixture was sealed under nitrogen, heated to 270 ° C., and reacted at 270 ° C. for 2.5 hours. After cooling, the reaction product was washed 5 times with warm water,
Then, the mixture was heated to 100 ° C., put into NMP, and continuously stirred for about 1 hour, filtered, and washed with hot water several times. This was heated to 90 ° C. and an aqueous solution of acetic acid of pH 4 25
The mixture was poured into a liter, continuously stirred for about 1 hour, filtered, washed with ion-exchanged water at about 90 ° C until the pH of the filtrate became 7, and then dried under reduced pressure at 80 ° C for 24 hours to obtain polyphenylene. Sulfide resin was used. The polyphenylene sulfide resin had a melting point of 282 ° C.

A spinning temperature of 32 using a molten liquid crystal-forming polyester resin as a core and a polyphenylene sulfide resin as a sheath.
The filament was discharged at 0 ° C., a nozzle diameter of 0.15 mmφ and a 10-hole spinneret and spun at a spinning speed of 1000 m / min to obtain a filament of 50 decitex. The performance of this spinning yarn is as follows: strength 5.6 cN / dtex, elongation 2.1%, elastic modulus 45.
It was 0 cN / dtex. This spinning raw yarn was continuously immersed in a 25%, 50 ° C. peracetic acid solution for oxidation treatment. The processing speed was adjusted so that the processing time at this time was 40 minutes.

The obtained yarn was heated at 400 ° C. using a melting point microscope.
The surface melting behavior was observed, but no melting was observed. This yarn at 250 ° C for 2 hours, 280 ° C for 2 hours, 3
Heat treatment was performed at 10 ° C. for 6 hours in a nitrogen gas atmosphere. The heat-treated yarn obtained had almost no interfiber sticking, had good rewindability, and had the following properties. Strength 20.5cN
/ Dtex elongation 3.2% elastic modulus 570 cN / dtex Comparative Example 1 The spinning raw yarn of Example 1 was used and 250 without oxidation treatment.
Heat treatment was performed in a nitrogen gas atmosphere at 2 ° C. for 2 hours, 280 ° C. for 2 hours, and 310 ° C. for 6 hours. When this yarn was taken out, the single yarns were fused together and could not be rewound, and could not be taken out as a fiber.

Comparative Example 2 The spinning raw yarn of Example 1 was used and 250
The heat treatment was performed at a temperature of 2 ° C. for 2 hours, at a temperature of 260 ° C. for 2 hours, and at a temperature of 270 ° C. for 6 hours in a nitrogen gas atmosphere. The surface melting behavior of this yarn at 400 ° C. was observed using a melting point microscope, but it was found to have melted when it exceeded 300 ° C. The heat-treated yarn obtained had almost no interfiber sticking on the surface and had the following properties, but tended to cause yarn breakage along the inner layer during rewinding.

Strength 18.2 cN / dtex, elongation 3.
2%, elastic modulus 545 cN / dtex Example 2 60 mol% of p-hydroxybenzoic acid, 20 mol% of 4,4-dihydroxybiphenyl, 10 mol% of terephthalic acid and 10 mol% of isophthalic acid as a core liquid crystal forming polyester. Which is a liquid crystal-forming polyester.
The melting point of the molten liquid crystal-forming polyester was 318 ° C. A 70 decitex filament was obtained by the same spinning method as in Example 1 except that the molten liquid crystal-forming polyester was used. This spinning raw yarn was continuously immersed in a 25%, 50 ° C. peracetic acid solution for oxidation treatment. The processing speed was adjusted so that the processing time at this time was 40 minutes.

The obtained yarn was subjected to a melting point microscope at 400 ° C.
The surface melting behavior was observed, but no melting was observed. This yarn at 250 ° C for 2 hours, 280 ° C for 2 hours, 3
Heat treatment was performed at 10 ° C. for 6 hours in a nitrogen gas atmosphere. The heat-treated yarn obtained had almost no interfiber sticking, had good rewindability, and had the following properties.

Strength 25.2 cN / dtex, elongation 2.
8%, elastic modulus 595 cN / dtex Example 3 p-Hydroxybenzoic acid and 2,6-hydroxynaphthoic acid were 72 as the core liquid crystal forming polyester.
A liquid crystal-forming polyester resin of / 28 mol% was used. The molten liquid crystal forming polyester resin has a melting point of 280 ° C.
Met. A filament of 50 decitex was obtained by the same spinning method as in Example 1 except that the molten liquid crystal-forming polyester was used.
The performance of the obtained spun yarn has a strength of 8.6 cN / dte.
x, elongation was 2.2% and elastic modulus was 450 cN / dtex. This spinning raw yarn was continuously immersed in a 25%, 50 ° C. peracetic acid solution for oxidation treatment. The processing speed was adjusted so that the processing time at this time was 40 minutes.

The obtained yarn was heated at 400 ° C. using a melting point microscope.
The surface melting behavior was observed, but no melting was observed. The spun raw yarn was heat-treated at 250 ° C. for 2 hours, at 260 ° C. for 2 hours, and at 270 ° C. for 6 hours in a nitrogen gas atmosphere.
The heat-treated yarn obtained had almost no interfiber sticking and had good rewindability and had the following properties.

Strength 18.4 cN / dtex, elongation 2.
6%, elastic modulus 530 cN / dtex

[0038]

INDUSTRIAL APPLICABILITY The present invention provides a composite fiber of a molten liquid crystal forming polyester and a polyphenylene sulfide resin,
The present invention solves the problem of interfiber fusion that occurs when solid-phase polymerization is performed to further improve the physical properties, and provides a high-strength composite fiber having better process passability than ever before.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) D06M 13/196 D06M 7/02 Z // D06M 101: 30 F term (reference) 4L031 AA12 AA19 AB04 BA08 BA33 CA02 DA17 4L033 AA04 AA07 AB01 AC11 AC15 BA16 4L041 BA02 BA05 BA21 BA46 BC04 BC20 BD02 BD06 BD20 CA10 CA35 CA61 DD01 DD05 DD14

Claims (4)

[Claims] 1. A core-sheath type composite fiber in which a core component is a molten liquid crystal forming polyester and a sheath component is a polyphenylene sulfide resin, and the strength of the composite fiber is 10 cN / dtex or more,
And a Young's modulus of 400 cN / dtex or more, and the sheath component is non-melting (not melting at 400 ° C.). 2. The high-strength conjugate fiber according to claim 1, which is a monofilament having a fineness of 20 dtex or less. 3. When a core-sheath type composite fiber is produced by using a melted liquid crystal forming polyester as a core component and a polyphenylene sulfide resin as a raw material as a sheath component, the sheath component is not melted by subjecting the melt-spun composite fiber to an oxidation treatment. Sex (400 ℃
The method for producing a high-strength conjugate fiber is characterized in that it is subjected to solid-state polymerization after the non-melting). 4. The method for producing a high-strength composite fiber according to claim 3, wherein the oxidation treatment is performed with a solution containing at least one of the following (1) to (3). (1) Organic peracid (2) Sodium hypochlorite (3) Hydrogen peroxide