JPS63157115A - Tension member provided with optical cable spacer - Google Patents

Abstract

PURPOSE:To increase the tensile strength, and also, to facilitate the extrusion molding by constituting a rod-like body having one piece or plural pieces of spiral grooves on the outside periphery, of melt workability polyester being capable of forming an anisotropic molten phase, and using it as a tension member. CONSTITUTION:A rod-like body consisting of melt workability polyester (liquid crystal polyester) being capable of forming an anisotropic molten phase is used as a base material, and on its outside periphery, one piece or more of spiral grooves 2 extending over the overall length are provided, and in its grooves, an optical fiber is fixed. As for the liquid crystal polyester, a molecular orientation occurs strongly in the surface part along a flow of a resin at the time of molding, and the tensile strength in its direction is extremely larger than the strength in the direction vertical to said direction. By the spiral groove 2 extending over the overall length of a tension member 1 provided with an optical cable spacer, the surface area increases, therefore, by the same cross-sectional area, the more strength can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a tension member in which a portion of a spacer for holding an optical fiber is integrated, which is used as a central tensile strength member of a multicore optical fiber cable of the present invention.

[Conventional technology and problems]

Various protection measures have been taken to protect multicore optical fiber cables from external forces. Among these, the tension member, which is located at the center of the cable and mainly supports the load, is an important element.

Conventionally, such tension members with spacers are
As tensile strength elements, pre-made wires of high-strength materials are used, such as steel wires, resin-impregnated glass fiber so-called pultruded FRP rods, and "Kepler" fibers. It is manufactured by extrusion molding a thermoplastic resin such as polyethylene into a profile using the same extrusion molding method used to form an insulating sheath on an electric wire. This conventional method requires a two-step process and has the problem of being time-consuming.

Means for Solving 5 Problems] In view of the above problems, the present inventors conducted intensive research on materials for optical cable tension members, and as a result, they developed a melt-processable polyester (hereinafter referred to as Focusing on the high strength of liquid crystalline polyester (abbreviated as "liquid crystalline polyester"), the present invention was completed after various further studies.

That is, the present invention provides a tension member with an optical cable spacer, which is a rod-shaped body made of liquid crystalline polyester and has one or more full-length spiral grooves on its outer periphery. .

The liquid crystalline polyester used in the present invention is a melt-processable polyester, and has the property that polymer molecular chains are regularly arranged in parallel in a molten state. The state in which the molecules are arranged in this way is often called the liquid crystal state or the nematic phase of liquid crystal materials. Such polymer molecules are generally elongated, oblate, fairly rigid along the long axis of the molecule, and have multiple chain extensions, usually in either coaxial or parallel relationships. Consisting of

The nature of the anisotropic melt phase can be confirmed by conventional polarization testing using crossed polarizers. More specifically, the anisotropic melt phase can be confirmed by observing a molten sample placed on a Leitz hot stage at 40x magnification under a nitrogen atmosphere using a Leitz polarizing microscope. The polymer is optically anisotropic. That is,
Transmits light when examined between orthogonal polarizers.

If the sample is optically anisotropic, polarized light will pass through it even if it is at rest.

Constituent components of the polymer that forms the anisotropic melt phase as described above include: - Consisting of one or more of aromatic dicarboxylic acids and alicyclic dicarboxylic acids - Aromatic diols, alicyclic diols, and aliphatic diols ■ Consisting of one or more aromatic hydroxycarboxylic acids ■ Consisting of one or more aromatic thiol carboxylic acids ■ One of aromatic dithiol, aromatic thiol phenol
Polyesters consisting of one or more of aromatic hydroxyamines and aromatic diamines and forming an anisotropic melt phase are polyesters consisting of ■)■ and ■■) Polyester consisting of only ■ Polyester consisting of ■) ■, ■ and ■ ■) Polythiol ester consisting only of ■ ■) Polythiol ester consisting of ■ and ■ ■) Polythiol ester consisting of ■ and ■ ■) ■ and ■ It is a polyester that forms an anisotropic melt phase composed of a combination of polyester amide consisting of ■), ■, polyester amide consisting of ■, and ■.

Furthermore, although not included in the above range of combinations of ingredients,
Polymers that form an anisotropic melt phase include aromatic polyazomethines, and specific examples of such polymers include poly-2-methyl-1,4-phenylenenitrilomethylidine-1,4-phenylenemethylidine. ) ; poly
trilo-2-methyl-1,4-phenylenenitrilomethylidine-1,4-phenylenemethylidine); Can be mentioned.

Furthermore, although it is not included in the above range of combinations of ingredients,
Polyester carbonate is included as a polymer that forms an anisotropic melt phase. It may consist essentially of 4-oxybenzoyl units, dioxyphenyl units, dioxycarbonyl units and terephthaloyl units.

The polyesters of 1), If), and m) and the polyesteramides of ①), which are polymers that form an anisotropic melt phase suitable for use in the present invention, have functional groups that form the required repeating units by condensation. It can be produced by various ester formation methods that allow the organic monomer compounds that are present to react with each other. For example, the functional groups of these organic monomer compounds include carboxylic acid groups, hydroxyl groups, ester groups, acyloxy groups, acid halides,
An amine group or the like may be used. The above organic monomer compounds can be reacted without the presence of a heat exchange fluid by a melt acidolysis 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 by-product volatiles (eg acetic acid or water) during the final stage of condensation.

Additionally, slurry polymerization methods can also be employed to form liquid crystalline polyesters suitable for use in the present invention.

In this process, a solid product is obtained in suspension in a heat exchange medium.

Regardless of whether the above-mentioned melt acidolysis method or slurry polymerization method is employed, the organic monomer reactant for inducing the liquid crystalline polyester is in a modified form in which the hydroxyl groups of the heptads are esterified (i.e., lower acyl esters). ) can be subjected to reaction. Furthermore, the lower acyl group preferably has about 2 to 4 carbon atoms.

Preferably, an acetate ester of such an organic monomer reactant is subjected to the reaction.

Furthermore, representative examples of catalysts that can optionally be used in either the melt acidolysis method or the slurry method include dialkyltin oxides (e.g., dibutyltin oxide), diaryltin oxides, titanium dioxide, antimony trioxide, alkoxytitanium silicates, titanium alkoxides. , alkali and alkaline earth metal salts of carboxylic acids (eg, zinc acetate), Lewis acids (eg, BFs), gaseous acid catalysts such as hydrogen halides (eg, HCI), and the like. The amount of catalyst used is generally about 0.05% based on the total weight of monomer.
0.001 to 1% 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. However, as previously mentioned, these polymers can be readily processed using conventional melt processing techniques. Particularly preferred liquid crystalline polymers are somewhat tolerant of 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 10,000 to 50,000. Particularly preferred is about 20,000 to 25,000. On the other hand, the preferred fully aromatic polyester amide P generally has a molecular weight of about 5.0.
00 to 50,000, preferably about io, ooo to 30
．． 000°, for example, 15,000 to 17,000.

Such molecular weight measurements can be carried out by gel permeation chromatography as well as other standard methods of measuring polymers that do not involve solution formation, such as quantification of end groups by infrared spectroscopy on compression molded films. Alternatively, the molecular weight can be measured using a light scattering method using a pentafluorophenol solution.

The liquid crystalline polyesters and polyesteramides described above also provide at least about 2.0 dl/g when dissolved in pentafluorophenol at 60°C at a concentration of 0.1% by weight.
, for example, a logarithmic viscosity of about 2.0 to 10.0 dl/g (1
,V,) is generally denoted.

The polymer exhibiting an anisotropic melt phase used in the present invention is preferably an aromatic polyester or an aromatic polyester amide, and a polyester partially containing an aromatic polyester or an aromatic polyester amide in the same molecular chain is also a preferred example. .

Preferred examples of the compounds constituting them are naphthalene compounds such as 2°6-naphthalene dicarboxylic acid, 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, and 6-hydroxy-2-naphthoic acid; Biphenyl compounds such as diphenyl dicarbon a, 4,4'-dihydroxybiphenyl, the following general formula (1), (If
) or (DI): (X: a group Y selected from alkylene (C+ to C4), alkylidene, -O-, -5O-1-S(h-, -s-, -CO-) Knee (CHz), l-(n□1~4), -0(CHz
), 0-(n・1 to 4)) benzene compounds substituted at the rose position such as p-hydroxybenzoic acid, terephthalic acid, hydroquinone, p-aminophenol, and p-phenylenediamine, and their nuclear substitutions. Benzene compound (substituent selected from chlorine, bromine, methyl, phenyl, 1-phenylethyl), isophthalic acid,
It is a meta-substituted benzene compound such as resorcinol.

In addition to the above-mentioned constituent components, the liquid crystalline polyester used in the present invention may also be polyalkylene terephthalate that does not partially exhibit an anisotropic melt phase in the same molecular chain. In this case, the alkyl group has 2 to 4 carbon atoms.

Among the above-mentioned components, a more preferred example is one containing one or more compounds selected from naphthalene compounds, biphenyl compounds, and para-substituted benzene compounds as an essential component. Among the p-substituted benzene compounds, p-hydroxybenzoic acid, methylhydroquinone and 1-phenylethylhydroquinone are particularly preferred examples.

Particularly preferred anisotropic melt phase forming polyesters for use in the present invention include repeating units containing naphthalene moieties such as 6-hydroxy-2-naphthoyl, 2,6-dihydroxynaphthalene and 2,6-dicarboxynaphthalene. It contains about 10 mol% or more. Preferred polyesteramides are those containing repeating units of the naphthalene moiety described above and a moiety consisting of 4-aminophenol or 1,4-phenylenediamine.

For specific examples of the compounds constituting the above-mentioned components I) to (ii) and specific examples of polyesters forming an anisotropic melt phase that are preferable for use in the present invention, see JP-A-61-69.
It is described in Publication No. 866.

The liquid crystalline polyester can further contain various inorganic fillers depending on the purpose.

Examples of inorganic substances include substances added to general thermoplastic resins and thermosetting resins, such as general N-free substances such as glass fibers, carbon fibers, metal fibers, ceramic fibers, boron fibers, potassium titanate fibers, and asbestos. Fiber, calcium carbonate, highly dispersed silicate, alumina, aluminum hydroxide, talc, clay, mica, glass flakes, glass powder, glass peas, quartz sand, silica sand, wollastonite, various metal powders, carbon black, barium sulfate,
Includes powder substances such as calcined gypsum, powder-grained or plate-like inorganic compounds such as silicon carbide, alumina, boron nitride, and silicon nitride, whiskers, and metal whiskers.

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

In order to improve the adhesiveness of the inorganic filler used in the present invention to the liquid crystalline polyester, it is possible and desirable to use a known surface treatment agent and binding agent used in -C together.

Examples include functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, and titanate compounds.

The inorganic filler may be used after being previously subjected to surface treatment or convergence treatment with these compounds, or may be added at the same time when preparing the material.

Furthermore, the liquid crystalline polyester of the present invention may be a polymer blend with other thermoplastic resins to the extent that the intended purpose of the present invention is not impaired.

The thermoplastic resin used in this case is not particularly limited, but examples include polyolefins such as polyethylene and polypropylene, and aromatic polyesters made of aromatic dicarboxylic acids and diols or oxycarboxylic acids such as polyethylene terephthalate and polybutylene terephthalate. ,
Polyacetal (homo or copolymer), polystyrene, polyvinyl chloride, polyamide, polycarbonate, A
Examples include BS, polyoxyphenylene oxide, polyoxyphenylene sulfide, and fluororesin. Moreover, these thermoplastic resins can be used in combination of two or more types. These resins also have mechanical,
In order to improve various properties such as electrical and chemical properties and flame retardancy, various additives and reinforcing agents can be added as necessary.

Also, known substances added to general thermoplastic resins and thermosetting resins, such as plasticizers, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, surface treatment agents, surfactants, and flame retardants. Coloring agents such as dyes and pigments, lubricants, lubricants, and crystallization accelerators (nucleating agents) for improving fluidity and mold release properties can also be used as appropriate depending on the required performance.

Liquid crystalline polyester has good fluidity when melted and has extremely excellent moldability, and can be easily molded using a normal profile extrusion molding method.

Regarding the spiral groove, which is the next requirement of the present invention, the size of the groove and the pitch of the spiral vary depending on the thickness and number of optical cables supported by this tension member and the purpose of use, but generally the groove is about several hundred mm. It's pitch. If this groove is straight, when the cable is wound around a drum or bent during wiring, tension is applied only to the optical cable and fiber located on the outside, which not only makes it difficult to bend, but also causes damage to the fiber. Therefore, the point is that when the optical cable group supported by this tension member is bent, the tension is applied to each optical cable as evenly as possible. Decisions must be made taking into account the losses that may occur.

It should be noted that when liquid crystalline polyester is molded, molecular orientation occurs strongly on the surface, and therefore the strength of the surface is greater than that of the inside. In the case of the tension member of the present invention, the surface area is advantageously increased by the helical groove along the entire length, but to take advantage of this feature, it is preferable to make the rod-shaped body hollow.

The cross-sectional shape of the hollow part is not particularly limited, but may be circular as shown in FIG. 3, but a star-shaped shape as shown in FIG. 4 will further increase the strength.

〔Effect of the invention〕

In the liquid crystalline polyester used in the present invention, molecular orientation occurs 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. This is extremely convenient for long molded products that are subject to force in the longitudinal direction. It is particularly advantageous for the present invention that this feature is exhibited in the extrusion direction of extrusion molding. Moreover, it is advantageous that it can be manufactured in one step of molding.

The outer shell of conventional tension members made of thermoplastic resin such as polyethylene cannot be expected to contribute much to strength, but by molding this part with liquid crystalline polyester, it has greater strength than conventional products with the same cross-sectional area. It is possible to obtain Furthermore, by making the center hollow, the strength per cross-sectional area of the material used can be improved, so it can be made even thinner, and from a different perspective, it can also save on the materials used.

In addition, since liquid crystalline polyester has a linear expansion coefficient equivalent to that of optical fiber, it eliminates friction caused by misalignment between the two due to environmental changes during use, reduces stress strain on the optical fiber, and eliminates fatigue caused by repeated tension-relaxation.
It's convenient. In addition to dispersing the tension applied to the outer fiber during bending, the spiral groove also alleviates fatigue caused by expansion and contraction due to environmental temperature changes.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.

Examples 1 to 5 and Comparative Example 1 Liquid crystalline polyester resins A and B described below.

Using C, D, and E, and using a material in which 30 parts by weight of carbon fiber was added to 100 parts by weight of these resins, it had an enlarged cross-sectional view as shown in Fig. 2, its diameter rl was 4.5 mm, and a core. A tension member 1 with a spacer having a diameter r2 of 2.3 mm+ and a spiral groove 20 Qmm was extruded.

The strength of this member is as shown in Table 1, and the diameter is 1
The strength was improved by about 20% compared to the 170 kg strength of the tension member with a spacer (Comparative Example 1), which was made of polyethylene with the same cross-sectional shape and a core material of FRP loft of 1.5 mm.

Table 1 Examples 6 to 10 Table 2 shows the strength of the tension members molded in the same manner as in Examples 1 to 5 without using carbon fiber.

Table 2 Examples 11 to 15 Hollow tension members as shown in FIG. 3 were manufactured in the same manner as Examples 1 to 5 except that a hollow portion with a circular cross section of 1.1 n+m in diameter was provided at the center.

The strength of this product was as shown in Table 3.

Table 3 Examples 16-20 As shown in FIG. 4, the distance r x = 2,
A hollow tension member was manufactured in the same manner as in Examples 1 to 5 except that it had a foot-shaped hollow part 4 with a diameter of 0ml ra = 0.8mm. The strength of this product was as shown in Table 4.

Table 4: Resins A to E used in Examples have the following structural units.

= 60/20/20 =70/15/l 5 1 = 60/20/20 (The above numbers are molar ratios)

[Brief explanation of the drawing]

1 is a perspective view showing an example of the tension member of the present invention; FIG. 2 is a schematic cross-sectional view of the tension member of FIG. 1; FIG. 3 is a schematic cross-sectional view of another example of the tension member of the present invention; FIG. 4 is a schematic cross-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)

[Claims] 1. A rod-shaped body made of melt-processable polyester capable of forming an anisotropic melt phase, characterized by having one or more full-length spiral grooves on its outer periphery. Tension member with optical cable spacer. 2. The tension member with an optical cable spacer according to claim 1, which has a hollow portion extending over the entire length approximately at the center.