JPH062236A - Conjugate stringy material - Google Patents

Abstract

PURPOSE:To improve the tenacity utilization ratio of yarn when formed into a cord by improving flexural fatigue resistance of high-strength fiber composed of an aromatic polyester capable of forming an anisotropic molten phase. CONSTITUTION:The objective conjugate stringy material is obtained by using high-tenacity fiber (A) composed of an aromatic polyester capable of forming an anisotropic molten phase. This stringy material is characterized by having a cross-sectional structure in which binder fiber (B) composed of a thermoplastic polymer is located in the core thereof and the fiber (A) is located in its outer peripheral part so as to surround the outer periphery of the fiber (B) and fusing the binder fiber (B) in the core part to the high-tenacity fiber (A) in its outer peripheral part in at least a part thereof by melting of the fiber (B).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high performance composite string using aromatic polyester fibers having a high strength and a high elastic modulus, which are made of aromatic polyester capable of forming an anisotropic melt phase.

[0002]

2. Description of the Related Art As string-like objects, drawn fibers,
There are twisted yarns, various braids, ropes, cords and the like made of them, and further, those whose surface is coated with a thermoplastic resin.

Fiber materials used in fields requiring high strength and high elastic modulus include carbon fibers, glass fibers, and
There are aramid fibers, and recently, high-strength polyethylene fibers and aromatic polyester fibers have been added, and these are used for various purposes.

However, when these fibers are formed into a rope-like material such as various ropes and cords, the carbon fibers and the glass fibers have extremely poor bending fatigue properties. Aramid fiber is not as bad as both of these fibers, but it is never good. On the other hand, high-strength polyethylene fibers have the drawbacks of insufficient heat resistance and weakness against rubbing. Further, the aromatic polyester fiber has a bending fatigue property as compared with the above fiber,
It has an excellent balance of heat resistance, but when made into a string-like material,
It was hard to say that the value of the strength utilization factor was sufficient, and the original fiber performance could not be fully exhibited.

In order to solve such a problem, a high-strength, low-elongation fiber made of an aromatic polyester compound capable of forming an anisotropic molten phase is formed into a string-like material, and the string-like material is coated with a thermoplastic resin. Attempts have also been made. (JP-A-63-06
1696, JP-A-3-269187).

However, when high-strength and high-modulus fibers are used as the core, even if the surface of the core is covered, the fibers are in direct contact with each other at the core, so that the fibers are abraded and the durability is poor. I have.

[0007]

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to improve the bending fatigue resistance of high-strength fibers and to improve the yarn performance when used as a cord, that is, the tenacity utilization factor. The present invention has been achieved through intensive research on this problem.

[0008]

The object of the present invention is to provide a cord-like material using a high-strength fiber A made of an aromatic polyester capable of forming an anisotropic melt phase, which is It has a cross-sectional structure in which a binder fiber B made of a plastic polymer is located in the core portion, and the fiber A is located in the outer peripheral portion so as to surround the outer periphery of the fiber B, and the binder fiber B in the core portion is also present. And the high-strength fiber A on the outer periphery of the
A composite string-like material, characterized in that at least a part thereof is fused by melting of the fiber B. It is achieved by adopting a configuration such that

The main fibers of the string-like material are high-strength fibers made of rigid polymers such as aramid, polyarylate, and polyamide-imide, high-strength fibers made of bent-chain polymers such as polyethylene and polyvinyl alcohol, carbon fibers, and alumina. Fiber, silicon carbide fiber, inorganic fiber such as glass fiber, or metal fiber may be used, but the target fiber of the present invention is an aromatic polyester fiber having excellent balance of bending fatigue resistance and heat resistance as described above. is there. The fiber made of this aromatic polyester is known as a so-called high-strength and high-modulus fiber, and is therefore simply referred to as a high-strength fiber in this specification to avoid complicated description of the fiber. Yes, and is not limited to the particular strength of the fiber.

The aromatic polyester capable of forming an anisotropic melt phase as referred to in the present invention is a polymer obtained from an aromatic diol, an aromatic dicarboxylic acid, an aromatic hydroxycarboxylic acid, etc., and has an optical difference in the melt phase. It shows the directionality (liquid crystallinity). Such characteristics can be easily identified by heating the sample on the hot stage in a nitrogen atmosphere and observing the transmitted light.

The anisotropic melting component used in the present invention comprises a combination of repeating structural units shown in the following chemical formula 1.

[0012]

[Chemical 1]

Particularly preferred is a polymer in which the proportion of the repeating constitutional units (I) and (II) represented by the following chemical formula 2 is 65% by weight or more, and particularly the component (II) is 5 to 45%. Certain aromatic polyesters are preferred.

[0014]

[Chemical 2]

In the melt-anisotropic polymer, other polymers or pigments, carbon, antioxidants, heat stabilizers, UV absorbers, etc. are added within the range in which the strength is not substantially reduced.
Additives such as lubricants and brightening agents may be included.

To obtain fibers from this melt-anisotropic polymer, the polymer melting temperature (sometimes referred to as the melting point)
Discharge from a nozzle so that the shear rate (γ) is 10 ³ sec ^-1 or more, preferably 10 ⁴ sec ^-1 or more, at a temperature higher than 10 ° C or higher and within a temperature range in which a molten liquid crystal is formed. Spinning is preferred. If this condition is not satisfied, the orientation of the molecules becomes insufficient and the desired high strength may not be obtained in the subsequent heat treatment. The shear rate (γ) is the shear rate (γ) = 4Q / πr ³ (sec) when the nozzle diameter is r (cm) and the polymer discharge amount per single hole is Q (cm ³ / sec). ^-1 ).

The fiber A made of an aromatic polyester capable of forming an anisotropic molten phase thus obtained is generally heat-treated to improve its strength.

By the way, the melting temperature of this fiber is gradually increased by the heat treatment. Therefore, a heat treatment temperature higher than the initial melting temperature is also performed.

The heat treatment may be carried out under tension or without tension depending on the purpose. In addition, the shape at that time is a mould-like shape, a cheese-like shape, a tow-like shape (which is processed by placing it on a wire mesh or the like), or a continuous processing between rollers.

The heat treatment atmosphere may be an inert gas such as nitrogen or argon, an active gas such as air or oxygen, or under reduced pressure. When the heat treatment gas has a dew point of −40 ° C. or lower, strength reduction due to hydrolysis of the ester does not easily occur.

The binder fiber B made of a thermoplastic polymer as referred to in the present invention is, for example, polyolefin such as polyethylene or polypropylene, polyvinyl chloride, nylon,
It is a single fiber made of a thermoplastic polymer such as polyester, polyurethane, polycarbonate and polyarylate. The other is to use these fibrous polymers as a core component and to newly add a third component different from the core component, for example, ethylene-vinyl alcohol copolymer, polyisoprene, polybutadiene, polyethylene, polyolefin such as polypropylene, polyester. It is a composite fiber in which thermoplastic polymers such as polyurethane, polycarbonate and polyarylate are combined as a sheath component.

Therefore, the cross-sectional shape of the binder fiber B is
As shown in FIG. 1 (a), a single body, or FIG.
It is a composite as shown in (g), and in the latter case, the core component 1 may be covered with the sheath component 2.

The commonly used additives may also be contained in the fiber B component polymer.

The composite string-like product of the present invention comprises a multi-strand composed of one or more kinds of high-strength fiber A made of aromatic polyester and binder fiber B made of thermoplastic polymer, each of which forms the anisotropic molten phase. As a non-twisted yarn of filaments, as a ply-twisted yarn, or as a aligned yarn composed of a plurality of these, further as a twisted yarn, as a braid, and further, a cord, a rope or the like composed of these plural yarns. In the present invention, the fiber B
Is located in the core part, and the fiber A is located in the surface layer part (outer peripheral part) so as to surround the outer periphery of the fiber B, and the fiber A of the surface layer part and the fiber B of the core part are at least a part thereof, Fiber B
It is characterized in that it is fused with.

In the present invention, it is essential to have a cross-sectional structure in which the fiber B is located in the core portion and the fiber A is located in the surface layer portion (outer peripheral portion) surrounding the outer periphery of the fiber B, and the fiber B is the surface layer surrounding the fiber A. The effect cannot be exerted when the fibers are located in a section or when the fibers A and B are arranged in parallel. This pulls on fiber A,
Alternatively, when a load such as bending is applied, it is presumed that the fiber B of the core portion becomes a good cushioning material and the mechanical characteristics of the fiber A are not deteriorated.

Further, in the fiber constitution of the present invention, the volume of the aromatic polyester fiber A is X _A , and the binder fiber B is
When the volume of X is X _B , the volume ratio X _B / (X _A + X _B ) of the fibers B in the two fibers is preferably in the range of 0.02 to 0.5. If this volume ratio is less than 0.02 and the amount of binder fiber B is small, the cushioning action and adhesion of the binder fiber are not sufficient, and it is impossible to expect improvement in bending fatigue property or strength utilization ratio. On the contrary, 0.5
If the amount of the binder fiber B exceeds the above range, the ratio of the component A decreases, and the desired strength cannot be obtained, which is outside the scope of the present invention.

Further, it is not enough that the fiber B is simply located at the center of the surface layer fiber made of the fiber A, and the fiber A in the surface layer and the fiber B in the core portion are fused at least at a part thereof. It is essential that It is considered that by fixing the fiber A in the string-like material, the interfiber wear of the fibers A can be suppressed, and as a result, the flex fatigue life is extended.

As the heat processing method for heat-bonding the binder fibers B in the above string-like material, a general heating roller or heating furnace can be used. The temperature of the heating body at this time is Tm-20 when the melting temperature of the binder fiber is Tm.
To Tm + 150 (° C.), it is preferable that the temperature is lower than the temperature at which the aromatic polyester fiber A thermally adheres.

As a method of increasing the heat fusion of the binder fiber B, there are a method of passing the pressure-sensitive roller while heating the string-like material, and a method of increasing the tension of the string-like material during processing.

As described above, the aromatic polyester fiber A having a high strength and a high elastic modulus under the above-mentioned conditions is heat-fused with the thermoplastic binder fiber B located in the core portion, so that it is stronger than the conventionally known string-like product. It has become possible to provide a high-strength, high-performance composite string-like material with improved utilization and flex fatigue.

The composite cord-like material of the present invention is particularly suitable for the following uses. Fishing line, sewing thread, fishing net, protective net for golf, protective net for baseball and software, center net for tennis and volleyball, soccer, handball, ice hockey, goal net for basketball, various protective items, sports equipment and ropes, cables, Various cords such as cords.

[0032]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The logarithmic viscosity [ηinh] of the polymer, the melting temperature Mp, the strength utilization factor of the string-like material, and the bending fatigue property (strength retention rate) were determined by the following measuring methods.

(1) Measurement of logarithmic viscosity [ηinh]: 0.1% by weight of a sample was dissolved in pentafluorophenol (6
Relative viscosity [ηre] in an Ubbelohde-type capillary viscometer (for example, "Polymer Science Experimental Method", Tokyo Kagaku Dojin P179 (1986) Tokyo) in a constant temperature bath of 0 to 80 ° C) and 60 ° C.
1] was measured and calculated by the following formula. The flow-down time of the solvent is 107 seconds. ηinh = [1n (ηrel)] / C where C is the polymer concentration (g / dl).

(2) Measurement of melting temperature Mp: 10 to 12 mg of a sample was placed in a DSC (for example, Mettler, TA-3000) device, sealed in an aluminum pan, and then 50 cc / N ₂ of carrier gas was used. Measured at a temperature rising rate of 20 ° C./min for a min flow rate, and indicated by the temperature at the position of the endothermic peak. Depending on the type of polymer,
In some cases, no clear endothermic peak appears in the first run (1st-Run), but in such a case, 5
At a heating rate of 0 ° C./min, the temperature is about 50 ° C. higher than the expected melting temperature for about 3 minutes to completely melt it, and then it is cooled to 50 ° C. at 80 ° C./min.
It is advisable to measure at a rate of temperature rise of min.

(3) Measurement of tenacity utilization factor: The value of tenacity utilization factor is the initial yarn strength DTyarn (g / d) of the fiber A.
And the breaking strength DTco (g / d) of the string-like material were calculated by the following formula. Strength utilization ratio = DTco / DTyarn × 100 However, the yarn fineness at the breaking strength DTyarn (g / d) is the sum of the total fineness of the fiber A and the binder fiber B.

(4) Measurement of flex fatigue (strength retention):
Using the tester shown in FIG. 2, the ratio D / d of the roller diameter (D) to the string diameter (d) of one string-shaped object was 25, the tensile tension was 2.4 kg, and the rotation speed of the reversing pulley was 300 times /
The test piece was reciprocated 250,000 times in min, and the breaking strength before and after the test was measured. The value of the strength retention was determined from the pre-test breaking strength K _A and the post-test breaking strength K _B by the following formula. Strong retention rate = K _B / K _A × 100

Example 1 As an aromatic polyester capable of forming an anisotropic melt phase, an aromatic polyester polymer having a molar ratio of the structural units (I) and (II) of the chemical formula 2 of 70/30 was used. . The physical properties of this polymer are ηin
h = 6.0 dl / g and Mp = 280 ° C. This polymer was discharged from a 320 ° C. spinning head equipped with a 50-hole spinneret, and 278 dr / 50 f at a winding speed of 800 m.
Fibers were obtained. This spun yarn is wound on a bobbin with holes and wound at a winding density of 0.57 g / cc, at 260 ° C. for 1 hour and at 270 ° C.
To 280 ° C for 3 hours, 280 ° C to 285 ° C for 5 hours
Heat treatment was performed for an hour.

The mechanical properties of the obtained heat treated yarn were yarn fineness (DR): 252 dr, yarn strength (DT): 26.2 g / d, yarn elongation (DE): 3.8%. This fiber was used as the component A of the composite string.

On the other hand, a circular cross-section composite fiber 200 having a core / sheath ratio of 7/3 using polyester as the core and polyethylene as the sheath.
dr / 20f was used as the binder fiber (component B).

Eight yarns 252dr / 50f of A component were combined to form a braid. At this time, B component 200 dr /
Two pieces of 20f were passed through the center of the braid to form a composite string. The volume ratio X _B / (X _A + X _B ) of the B component was 0.18. Subsequently, the string-like material was heated in a furnace preheated to 180 ° C. for 10 seconds and then passed through a heat roller to heat-bond the sheath component of the binder fiber B to obtain a composite string-like material.

Table 1 shows the results of the strength retention and flex fatigue of the composite cord-like material of the present invention thus produced.

Example 2 The same aromatic polyester fiber as in Example 1 was used as component A, while the binder fiber was a polyester resin having a core / polyester sheath and a copolymer / polyester sheath having a core / sheath ratio of 7/3. Composite fiber 200 dr /
20f was used as the B component. The composition of the copolyester is 27.5 mol% terephthalic acid, 22.5 mol% isophthalic acid, 45.0 mol% ethylene glycol, and 5.0 mol% diethylene glycol.

As in Example 1, the A component yarn 252d
8 pieces of r / 50f were combined to form a braid. At this time, two B components of 200 dr / 20f were passed through the center of the braid to form a composite string. Volume ratio of B component X _B / (X _A + X
_B ) was 0.18. Continuously, the string-like material
After heating for 10 seconds in a preheated furnace, it was passed through a heating roller to heat-bond the sheath component of the binder fiber B to form a composite string. Table 1 shows the results of the strength retention and flex fatigue of this composite string.

Example 3: The structural unit is (I
II) / (IV) / (V) / (VI) mol% ratio is 60
Melt spinning was performed using an aromatic polyester polymer of /5/17.5/17.5. The physical properties of this polymer are η
inh = 6.7 dl / g and Mp = 349 ° C.

[0045]

[Chemical 3]

This polymer is spun at a discharge temperature of 362 ° C.
The same procedure as in Example 1 was carried out except that the above was carried out, and the obtained spun raw yarn was rewound under the same conditions as in Example 1,
Heat treatment was performed for 3 hours from 290 ° C. to 310 ° C. for 5 hours from 315 ° C. to 325 ° C.

The mechanical properties of the heat-treated yarn obtained were as follows: yarn fineness (DR): 255 dr yarn strength (DT): 21.8 g / dr yarn elongation (DE): 2.1%. It was used as the A component of.

The same binder fiber as in Example 1 (component B)
Was used, and a composite string was prepared under the same conditions. The volume ratio X _B / (X _A + X _B ) of the B component was 0.09. Table 1 shows the results of the strength utilization ratio and flex fatigue of this composite string.

Comparative Example 1 Using the same aromatic polyester fiber A as in the example, 8 braids were made without the binder fiber B. That is, the volume ratio of the B component X _B / (X _A + X
_B ) is 0. Table 1 shows the results of the strength utilization factor and bending fatigue resistance of this string-like material.

Comparative Example 2: Using the same A component fiber and B component fiber as in Example 1, the A component yarn 252 dr /
4 pieces of 50f were combined to form a braid. At this time, pass 7 B components of 200 dr / 20f through the center of the braid,
It was a composite string. Volume ratio of B component X _B / (X _A + X _B )
Was 0.6. Subsequently, heat fusion was performed under the same conditions as in Example 1 to obtain a composite string-like material. Table 1 shows the results of the strength utilization factor and bending fatigue resistance of this string-like material.

Comparative Example 3 A high performance composite was prepared in the same manner as in Example 1 except that the aromatic polyester fiber A was replaced by Kevlar R (manufactured by DuPont) which is an aramid fiber and 10 yarns of 200 dr / 134f were combined. I made a string. The mechanical properties of Kevlar R were DR = 204 dr DT = 22.4 g / d DE = 3.6%. Table 1 shows the results of the strength utilization ratio and flex fatigue of this composite string.

[0052]

[Table 1]

[0053]

EFFECT OF THE INVENTION The high-performance composite string-shaped article obtained by compounding the aromatic polyester fiber capable of forming the anisotropic molten phase with the thermoplastic binder fiber of the present invention has excellent bending fatigue property and high strength utilization rate. It is useful as fishing line, sewing thread, fishing net, various sports protection nets, ropes, cables and cords.

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of a representative binder fiber that can be used in the present invention.

FIG. 2 is an explanatory diagram of a bending fatigue test.

[Explanation of symbols]

1 Core component in binder composite fiber 2 Sheath component in binder composite fiber 3 String to be tested 4 Free roller 5 Reverse pulley 6 Spring

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location D04C 1/12 D07B 1/04

Claims (1)

[Claims] 1. A cord-like material using a high-strength fiber A made of an aromatic polyester capable of forming an anisotropic molten phase,
The string-like material has a cross-sectional structure in which a binder fiber B made of a thermoplastic polymer is located in the core part thereof, and the fiber A is located in the outer peripheral part so as to surround the outer periphery of the fiber B, and At least a part of the binder fiber B of the core portion and the high-strength fiber A of the outer peripheral portion of the fiber B
A composite string-like object characterized by being fused by melting of.