JP2513653B2 - Tension member with optical cable spacer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a tension member in which a spacer portion holding an optical fiber used as a central tensile strength member of a multi-core optical fiber cable of the present invention is integrated.

[Conventional technology and problems]

Various protective measures have been taken to protect the multi-core optical fiber cable by external force. Above all, the tension member that mainly supports the load at the center of the cable is an important element.

Conventionally, such a tension member with a spacer uses a steel wire as a tensile strength element, a resin-impregnated glass fiber so-called pull-out method FRP rod, a preformed high-strength material linear material such as `` Kevlar '' fiber, In order to provide a groove for fixing an optical fiber, the outer surface of the optical fiber is manufactured by profile extrusion coating molding of a thermoplastic resin such as polyethylene by the same extrusion coating molding method as that for forming an insulating coating of an electric wire. This conventional method requires a two-step process,
There was a problem that it was troublesome.

[Means for solving problems]

In view of the above problems, the inventors of the present invention have conducted extensive studies on the material of the optical cable tension member, and as a result, melt-processable polyester (hereinafter,
Focusing on the high strength of liquid crystal polyester), the present invention has been completed through various studies.

That is, the present invention is a rod-shaped body made of liquid crystalline polyester, characterized in that it has one or more spiral grooves extending over the entire length thereof and a hollow portion extending over the entire length at substantially the center thereof. A tension member with an optical cable spacer is provided.

The liquid crystalline polyester used in the present invention is a melt-processable polyester and has a property that the polymer molecular chains take a regular parallel arrangement in a molten state. The state in which molecules are arranged in this manner is often referred to as a liquid crystal state or a nematic phase of a liquid crystal substance. Such polymer molecules are generally elongated, flat, and fairly stiff along the long axis of the molecule,
Consisting of polymers having a plurality of chain extension bonds, usually in either a coaxial or parallel relationship.

The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using a crossed polarizer. More specifically, the confirmation of the heterogeneous molten phase can be carried out by using a Leitz polarization microscope and observing the molten sample placed on the Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times. The polymer is optically anisotropic. That is, it transmits light when inspected between crossed polarizers. If the sample is optically anisotropic, polarized light will be transmitted even if it is stationary.

The constituent component of the polymer forming the anisotropic molten phase as described above comprises one or more of aromatic dicarboxylic acid and alicyclic dicarboxylic acid. 1 of aromatic diol, alicyclic diol and aliphatic diol. One or more One or more aromatic hydroxycarboxylic acids One or more aromatic thiolcarboxylic acids One or more aromatic dithiols, aromatic thiolphenols A polymer selected from aromatic hydroxyamines, ones or more of aromatic diamines, etc., and the polymer forming the anisotropic molten phase is a polyester II) consisting of I) and a polyester III) consisting only of Polyester consisting of IV) Polythiol ester consisting only of V) Polythiol ester consisting of Ether VI) is a polyester that forms a composed anisotropic melt phase from the combination of such polyesteramides consisting polythiol ester VII) polyester amides VIII) and consisting of Toto and capital consisting Toto.

Further, although not included in the category of the combination of the above components, the polymer forming the anisotropic molten phase includes aromatic polyazomethine, and specific examples of such a polymer include:
Poly (nitrilo-2-methyl-1,4-phenylene nitriloethylidyne-1,4-phenyleneethylidine); poly (nitrilo-2-methyl-1,4-phenylene nitrilomethylidyne-1,4-phenylenemethylidine ); And poly (nitrilo-2-chloro-1,4-phenylene nitrilomethylidine-1,4-phenylenemethylidine).

Further, although not included in the category of the combination of the above components, polyester carbonate is included as the polymer forming the anisotropic molten phase. It consists essentially of 4-oxybenzoyl units, dioxyphenyl units, dioxycarbonyl units and terephthaloyl units.

The polyesters of the above I), II) and III) and the polyesteramides of VIII), which are polymers forming an anisotropic molten phase suitable for use in the present invention, have a functional group capable of forming a required repeating unit by condensation. It can be produced by various ester forming methods capable of reacting the organic monomer compounds with each other. For example, the functional groups of these organic monomer compounds are carboxylic acid groups, hydroxyl groups, ester groups, acyloxy groups, acid halides,
An amine group may be used. The above-mentioned organic monomer compound can be reacted without a heat exchange fluid by a melt acidosis method. In this method, the monomers are first heated together to form a molten solution of the reactants. As the reaction continues, solid polymer particles become suspended in the liquid. Vacuum may be applied to facilitate removal of volatiles (eg acetic acid or water) by-produced in the final stage of the condensation.

Also, a slurry polymerization method can be employed for forming a liquid crystalline polyester suitable for use in the present invention. in this way,
The solid product is obtained in suspension in a heat exchange medium.

Regardless of which of the above-mentioned melt-acidification method and slurry polymerization method is employed, the organic monomer reactant that induces the liquid crystalline polyester is in a modified form in which the hydroxyl group of such a monomer is esterified (that is, as a lower acyl ester). It can be subjected to a reaction. Further, the lower acyl group preferably has about 2 to 4 carbon atoms. Preferably, the acetic acid ester of such an organic monomer reactant is subjected to the reaction.

Representative examples of catalysts that can be optionally used in either the melt acidilysis method or the slurry method include dialkyltin oxide (eg, dibutyltin oxide), diaryltin oxide, titanium dioxide, antimony trioxide, alkoxytitanium silicate, and titanium alkoxide. , Alkali and alkaline earth metal salts of carboxylic acids (eg, zinc acetate), Lewis acids (eg, BF ₃ ), hydrogen halides (eg, HC
l) and other gaseous acid catalysts. The amount of catalyst used is generally from about 0.001 to 1 based on the total weight of the monomers.
% By weight, especially about 0.01 to 0.2% by weight.

Liquid crystalline polymers suitable for use in the present invention tend to be substantially insoluble in common solvents and are therefore unsuitable for solution processing. But as already mentioned,
These polymers can be easily processed by conventional melt processing methods. Particularly preferred liquid crystalline polymers are somewhat soluble in pentafluorophenol.

Liquid crystalline polyesters suitable for use in the present invention generally have a weight average molecular weight of about 2,000 to 200,000, preferably about 1
It is preferably from 20,000 to 50,000, particularly preferably from about 20,000 to 25,000. On the other hand, suitable wholly aromatic polyesteramides generally have a molecular weight of about 5,000 to 50,000, preferably about 10,000 to 30,
000, for example, 15,000 to 17,000. The measurement of such a molecular weight can be carried out by a standard measurement method which does not involve solution formation of gel permeation chromatography and other polymers, for example, by quantifying an end group by infrared spectroscopy on a compression molded film. The molecular weight can also be measured by using a pentafluorophenol solution and using a light scattering method.

The above-mentioned liquid crystalline polyesters and polyester amides also contain 0.1% by weight of pentafluorophenol at 60 ° C.
It typically exhibits an inherent viscosity (IV) of at least about 2.0 dl / g, for example about 2.0 to 10.0 dl / g when dissolved at a concentration.

The polymer exhibiting the anisotropic melt phase used in the present invention is
Aromatic polyesters and aromatic polyesteramides are preferable, and aromatic polyesters and polyesters partially containing aromatic polyesteramides in the same molecular chain are also preferable examples.

Preferred examples of compounds constituting them are 2,6-naphthalenedicarboxylic acid, 2,6-dihydroxynaphthalene,
1,4-dihydroxynaphthalene and 6-hydroxy-2
-Naphthalene compounds such as naphthoic acid, biphenyl compounds such as 4,4'-diphenyldicarboxylic acid and 4,4'-dihydroxybiphenyl, the following general formulas (I), (II) or (II)
Compound represented by I): (However, X: alkylene (C _{1 to} C ₄ ), alkylidene, -0
A group selected from —, —SO—, —SO ₂ —, —S—, and —CO— Y: — (CH ₂ ) _n — (n = 1 to 4), —O (CH ₂ ) _n O—
(Group selected from n = 1 to 4) Para-substituted benzene compounds such as p-hydroxybenzoic acid, terephthalic acid, hydroquinone, p-aminophenol and p-phenylenediamine, and their nucleus-substituted benzene compounds (substituents) Are selected from chlorine, bromine, methyl, phenyl, 1-phenylethyl), isophthalic acid, resorcin, and the like, and meta-substituted benzene compounds.

Further, the liquid crystalline polyester used in the present invention may be a polyalkylene terephthalate which does not partially show an anisotropic melt phase in the same molecular chain, in addition to the above-mentioned constituents. In this case, the alkyl group has 2 to 4 carbon atoms.

Among the above-mentioned components, those containing one or more compounds selected from a naphthalene compound, a biphenyl compound and a para-substituted benzene compound as essential components are more preferable examples. Of the p-position-substituted benzene compounds, p-hydroxybenzoic acid, methylhydroquinone and 1-phenylethylhydroquinone are particularly preferable examples.

Particularly preferred polyesters that form an anisotropic melt phase for use in the present invention include repeating units containing a naphthalene moiety such as 6-hydroxy-2-naphthoyl, 2,6-dihydroxynaphthalene and 2,6-dicarboxynaphthalene. About 10
It is contained in an amount of not less than mol%. Preferred polyesteramides are those containing repeating units of the naphthalene moiety described above and a moiety consisting of 4-aminophenol or 1,4-phenylenediamine.

Incidentally, specific examples of the compounds constituting the above-mentioned I) to VIII) and specific examples of the polyester forming the anisotropic melt phase which is preferable for use in the present invention are described in JP-A-61-698.
No. 66 publication.

The liquid crystalline polyester may further contain various inorganic fillers depending on the purpose. Examples of the inorganic substance include substances added to general thermoplastic resins and thermosetting resins, that is, general inorganic fibers such as glass fiber, carbon fiber, metal fiber, ceramic fiber, boron fiber, potassium titanate fiber, and asbestos. , Calcium carbonate, highly dispersible silicate, alumina, aluminum hydroxide, talc, clay, mica, glass flakes, glass powder, glass beads, quartz sand, silica sand, wollastonite, various metal powders, carbon black, sulfuric acid It includes powder substances such as barium and calcined gypsum, powdered particles of silicon carbide, alumina, boron nitrite, silicon nitride and the like, plate-like inorganic compounds, whiskers and metal whiskers and the like.

These inorganic fillers may be used alone or in combination of two or more.

Since the inorganic filler used in the present invention enhances the adhesiveness to the liquid crystalline polyester, it is possible and desirable to use a commonly used known surface treatment agent and sizing agent together.

Examples are functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, titanate compounds and the like.

The inorganic filler may be used after being subjected to surface treatment or converging treatment with these compounds in advance, or may be added at the same time when the material is adjusted.

Further, the liquid crystalline polyester of the present invention may be a polymer blended with another thermoplastic resin within a range that does not impair the intended purpose of the present invention.

The thermoplastic resin used in this case is not particularly limited, but examples thereof include polyolefins such as polyethylene and polypropylene, aromatic dicarboxylic acids such as polyethylene terephthalate and polybutylene terephthalate, and aromatic polyesters comprising diols or oxycarboxylic acids. , Polyacetal (homo or copolymer), polystyrene, polyvinyl chloride, polyamide, polycarbonate, ABS, polyoxyphenylene oxide, polyoxyphenylene sulfide, fluororesin and the like. Further, these thermoplastic resins can be used as a mixture of two or more kinds. Further, in order to improve various properties such as mechanical, electrical and chemical properties and flame retardancy, it is possible to add various additives and reinforcing agents to these resins, if necessary. .

Further, known substances added to general thermoplastic resins and thermosetting resins, that is, plasticizers, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, surface treatment agents, surfactants,
Flame retardants, colorants such as dyes and pigments, lubricants for improving fluidity and releasability, lubricants, crystallization accelerators (nucleating agents) and the like can be appropriately used depending on the required performance.

The liquid crystalline polyester has a good fluidity when melted and is extremely excellent in moldability, and can be easily molded by an ordinary profile extrusion molding method.

Regarding the spiral groove which is the next requirement of the present invention, both the groove size and the spiral pitch vary depending on the thickness and the number of optical cables supported by this tension member and the purpose of use, but generally about several hundred millimeters. The pitch. When the groove is straight, tension is applied only to the optical cable and the fiber located outside when the cable is wound on a drum or bent at the time of wiring, which is not only difficult to bend but also damages the fiber. Therefore, the point is to make the tension evenly applied to each optical cable as much as possible when the optical cable group supported by this tension member is bent. You must make a decision considering the loss that will occur.

The liquid crystalline polyester has a strong molecular orientation at the surface portion during molding, and therefore the surface strength is greater than that inside.
In the case of the tension member of the present invention, the surface area is increased due to the spiral groove extending over the entire length, which is convenient,
Furthermore, in order to take advantage of this feature, the rod is made hollow.
The cross-sectional shape of the hollow portion is not particularly limited, but it may be circular as shown in FIG. 3, but a star shape as shown in FIG. 4 will further improve the strength.

〔The invention's effect〕

Since the liquid crystalline polyester used in the present invention undergoes molecular orientation along the flow of the resin during molding, and the tensile strength in that direction is extremely large compared to the strength in the direction perpendicular to this, it is unidirectional as in the present invention. It is extremely convenient for a molded product that is extremely long and that exerts a force in its longitudinal direction. In particular, it is extremely convenient for the present invention that this feature is exhibited in the extrusion direction of extrusion molding. Moreover, it is convenient that it can be manufactured by one-step molding.

The outer part of the conventional tension member made of thermoplastic resin such as polyethylene cannot be expected to contribute much in terms of strength, but by molding this part with liquid crystalline polyester, more strength can be achieved with the same cross-sectional area than conventional products. It is possible to obtain Further, by making the center part hollow, the strength per cross-sectional area of the used material can be improved, so that it can be made thinner, and if the viewpoint is changed, the used material can be saved.

Further, since the liquid crystalline polyester has a coefficient of linear expansion equivalent to that of an optical fiber, friction between the two due to environmental changes during use is eliminated, stress strain of the optical fiber is reduced, and fatigue due to repeated tension-relaxation is eliminated. It is convenient. The spiral groove relieves the fatigue caused by the expansion and contraction due to the temperature change of the ring mirror, in addition to the above-mentioned dispersion of the tension applied to the outer fiber at the time of bending.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to examples.

Reference Examples 1 to 5 and Comparative Example 1 Liquid crystalline polyester resins A, B, C, D and E, which will be described later, are used, and 100 parts by weight of these resins are used, and a material in which 30 parts by weight of carbon fiber is added is used. Having an enlarged cross-sectional view as shown,
Tension member 1 with spacer having diameter r ₁ of 4.5 mm, core diameter r ₂ of 2.3 mm, and groove 2 with spiral pitch of 200 mm
Was extruded.

The strength of this member is as shown in Table 1, and the diameter
The strength of the tension member with a spacer (Comparative Example 1) composed of polyethylene of the same cross-section with a 1 mm FRP rod as the core material was improved by about 20% compared to the strength of 170 kg.

Reference Examples 6 to 10 The strength of the tension members similarly molded without using carbon fibers in Reference Examples 1 to 5 was as shown in Table 2.

Examples 1 to 5 Hollow tension members as shown in FIG. 3 were manufactured in the same manner as in Reference Examples 1 to 5 except that the hollow portion having a circular cross section with a diameter of 1.1 mm was provided at the center. The strength of this product was as shown in Table 3.

Examples 6 to 10 As shown in FIG. 4, the distance r ₃ = 2.0 mm, r ₄ = at the center.
Reference Examples 1 to 5 except having a 0.8 mm star-shaped hollow portion 4
A hollow tension member was manufactured in the same manner as in. The strength of this product was as shown in Table 4.

The resins A to E used in the examples have the following constitutional units.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of the tension member of the present invention, FIG. 2 is a schematic sectional view of the tension member of FIG. 1, and FIG. 3 is a schematic sectional view of another example of the tension member of the present invention. FIG. 4 is a schematic sectional view of still another example of the tension member of the present invention. 1 ... Tension member 2 ... Spiral groove 3,4 ... Hollow part

Claims (1)

(57) [Claims] 1. A rod-shaped body made of melt-processable polyester capable of forming an anisotropic molten phase, having one or more spiral grooves extending over the entire length thereof, and having a full-length center substantially at its center. A tension member with an optical cable spacer, which has a hollow portion extending over.