JPH02113003A - Reinforcing material for optical fiber cable - Google Patents

Abstract

PURPOSE:To obtain the subject material, consisting of a molecular oriented substance of a specific ultrahigh-molecular weight ethylene.alpha-olefin copolymer without deterioration in transmission characteristics due to no water absorbability and excellent in creep properties and impact resistance. CONSTITUTION:The objective material consisting of a molecular oriented substance of an ultrahigh-molecular weight ethylene.alpha-olefin copolymer having >=5dl/g intrinsic viscosity [eta] and 0.1-20 content of >=3C alpha-olefin based on 1000 number of carbon atoms. The above-mentioned molecular oriented substance is obtained by blending, e.g., an ultrahigh-molecular weight ethylene.alpha-olefin copolymer prepared by slurry polymerization using a Ziegler-based catalyst with a diluent, such as n-nonane, melt kneading the resultant mixture, melt extrusion molding the obtained spinning solution and then drawing the resultant undrawn molded body so as to apply molecular orientation to at least one direction thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reinforcing material for optical fiber cables, and more specifically, the present invention relates to a reinforcing material for optical fiber cables. This invention relates to reinforcing materials for optical fiber cables.

Technical background of the invention and its problems In recent years, optical communications using optical fiber cables have begun to be used. This optical communication transmits audio or image information as an optical signal, and an optical fiber cable is used as a transmission medium for the optical signal.

Conventionally, so-called optical fiber cables have been used by assembling a plurality of single-core fiber cords into various shapes. Many methods of combining sets have been proposed.

One example is a structure in which a plurality of single-core optical fiber bar cords are assembled, a tensile strength fiber layer is placed along the outer peripheral surface of the optical fiber core, and this is further covered with a PvC (polyvinyl chloride) resin layer.

The light transmission properties of fiber optic bar codes are significantly affected by the tensile and compressive stresses on the fiber optic cord itself. In other words, the transmission characteristics significantly deteriorate with respect to tensile and compressive deformations with the stress-free state at the peak. The decrease is particularly remarkable under tensile stress. Such stress on the optical fiber bar code itself does not occur during normal installation, but for example, if the cable itself is stretched while being installed, residual stress may remain locally unrelieved. , also occurs and remains when installed in passages with small curvature. Furthermore, if the structure is installed in the air, tensile stress will always be applied due to its own weight. Thus, during installation, any fiber optic cable requires a high tensile strength fiber layer in order to prevent stress after installation from being applied to the fiber optic bar cord itself. Fiber optic cables that do not contain a tensile fiber layer are rare, if any. As the material for the tensile strength fiber layer, glass fiber, carbon fiber, metal wire, heat-resistant organic fiber, etc. are used. Conventionally, organic fibers have been selected as the material for the tensile strength fiber layer in order to particularly improve compatibility with PVA resin and improve mechanical properties. Among organic fibers, para-aramid fibers, which have particularly excellent elastic modulus and strength, are selected as the material for tensile strength wires.

However, when such para-aramid fibers are used in the tensile strength fiber layer, their equilibrium moisture content reaches as high as 3.5%. Optical fiber bar cords are manufactured with various structures, but the core wire is usually one in which a cladding is applied to the iGI type 31 core and a support layer is provided on the outside. A buffer layer and a thermoplastic resin film are sequentially laminated on the surface to form an optical fiber barcode. A silicon-based rubber material with a small compressive Young's modulus is used for the buffer layer. Further, the thermoplastic resin film protects the optical fiber core wire, and a film having a low water absorption rate, a relatively small Young's modulus, and high flexibility is used. A typical material suitable for this thermoplastic resin film is nylon, and in fact, nylon is used as the thermoplastic resin film in most optical fiber bar codes.

The equilibrium water content of this nylon layer is 1% or less, and lowering this equilibrium water content directly leads to the maintenance of long-term high transmission characteristics of the optical fiber core wire.

In other words, when a tensile strength fiber layer made of para-aramid fiber exists adjacent to the nylon layer, it becomes a source of moisture in the long term, making it difficult to maintain the high transmission characteristics of optical fiber barcodes over a long period of time. . In fact, optical cables using such tensile strength fiber layers made of para-aramid fibers often experience a significant decline in optical transmission characteristics after about 6 months have passed, which has become a major problem. There is. Also, the density of para-aramid fiber is 1.
45, it is not effective for weight reduction. In view of these problems, tensile strength fiber layers made of high modulus and high strength polyethylene fibers have been proposed in recent years. High elastic modulus, high strength polyethylene fiber has excellent elastic modulus and strength, and has a specific gravity of 0.98, so its specific elastic modulus and specific strength are superior to para-aramid fibers. In addition, since the equilibrium water content is 0.1% or less, the drawbacks of para-aramid fibers, such as water absorption and lightness, are overcome. However, compared to para-aramid fibers, high-modulus, high-strength polyethylene is inferior in creep resistance, and if the tensile stress during installation is not partially resolved, tensile stress will be applied to the optical fiber bar code over a long period of time, resulting in transmission. It has the disadvantage of being difficult to handle because it impairs its properties.

Furthermore, the elongation at break of para-aramid fiber and high-modulus, high-strength polyethylene fiber is 2% and 4%, respectively, both of which are smaller than the 6% or more of optical fiber, and from the perspective of impact resistance. is also not a desirable material. In particular, in the case of high-modulus, high-strength polyethylene fibers, the melting point is extremely low, so complicated considerations are required when coating with PVC resin.

Purpose of the Invention The present invention aims to solve the above-mentioned problems associated with the prior art. The object of the present invention is to provide a material for a tensile strength fiber layer for an optical fiber cable, that is, a reinforcing material for an optical fiber cable.

Summary of the Invention The reinforcing material for optical fiber cables according to the present invention has an intrinsic viscosity [η of at least 5 dl/g, and an average content of α-olefin having 3 or more carbon atoms of 0.1 to 1000 carbon atoms. 20 ultra-high molecular weight ethylene α
-It is characterized by being composed of a molecularly oriented body of an olefin copolymer.

Since the reinforcing material for optical fiber cables according to the present invention is made of the molecularly oriented ultra-high molecular weight ethylene/α-olefin copolymer as described above, it does not absorb water and therefore does not deteriorate the transmission characteristics of the optical fiber. Moreover, it has excellent creep resistance and impact resistance.

DETAILED DESCRIPTION OF THE INVENTION The reinforcing material for optical fiber cables according to the present invention will be specifically described below.

First, the molecularly oriented ultrahigh molecular weight ethylene/α-olefin copolymer constituting the reinforcing material for optical fiber cables according to the present invention will be explained.

The molecularly oriented ultrahigh molecular weight ethylene/α-olefin copolymer used in the present invention is a molecularly oriented body of ultrahigh molecular weight ethylene of ethylene and an α-olefin having 3 or more carbon atoms.・The α-olefin copolymer has an intrinsic viscosity [η] of at least 5 dll/g or more, and the α-olefin has a carbon number of 1 in the copolymer.
It is contained in the ultra-high molecular weight ethylene/α-olefin copolymer in an average amount of 0.1 to 20 pieces per 1,000 fli.

1. Ultra-high molecular weight polyester constituting the molecularly oriented molded product used in the present invention. Examples of the N/α-olefin copolymer include ultra-high molecular weight ethylene/propylene copolymer, ultra-high molecular weight ethylene/l-butene copolymer, and ultra-high molecular weight ethylene/4-butene copolymer.
Methyl-1-pentene copolymer, ultra-high molecular weight ethylene,
1-hexene copolymer, ultra-high molecular weight ethylene/l-octene copolymer, ultra-high molecular weight ethylene/1-decene copolymer, etc., containing ethylene and carbon atoms of 3 to 20. Preferred examples include ultra-high molecular weight ethylene/α-olefin copolymers with 4 to 10 α-olefins. In this ultra-high molecular weight ethylene/α-olefin copolymer, the number of α-olefins having 3 or more carbon atoms is 0.1 to 20, preferably 0.5 to 1 per 1000 carbon atoms of the polymer.
It is contained in an amount of 0 pieces, more preferably 1 to 7 pieces.

The molecularly oriented molded product obtained from such an ultra-high molecular weight ethylene-α-olefin copolymer has particularly excellent impact resistance and creep resistance compared to the molecularly oriented molded product obtained from ultra-high molecular weight polyethylene. . This ultra-high molecular weight ethylene/α-olefin copolymer is lightweight and has high strength, and has excellent abrasion resistance, impact resistance, and creep resistance, as well as weather resistance, water resistance, and salt water resistance.

The ultra-high molecular weight polyolefin or ethylene/α-olefin copolymer constituting the molecularly oriented molded article used in the present invention has an intrinsic viscosity [η] of 5 dll/g or more, preferably in the range of 7 to 30 dR/g, The molecularly oriented molded product obtained from this copolymer has excellent mechanical properties and heat resistance. That is, since molecular terminals do not contribute to fiber strength and the number of molecular terminals is the reciprocal of the molecular weight (viscosity), it can be seen that a material with a large intrinsic viscosity [η] gives high strength.

The density of the molecularly oriented molded product used in the present invention is 0.990
to 0.900 g/ad, preferably 0.960 to 0.985 g/ad.

Here, the density is determined according to the standard method (ASTM D 1505),
It was measured using the density gradient tube method. The density gradient tube at this time was prepared by using carbon tetrachloride and toluene, and the measurement was performed at room temperature (23° C.).

Dielectric constant (IKHz
, 23°C) is 1.4 to 3.0, preferably 1.8 to 2.4, and the positive dissipation tangent (lKHz, 80°C) is 0.
．． 0.05 to 0.08%, preferably 0.040 to 0.010%. Here, the dielectric constant and positive voltage junction were determined using ASTM D using a film-like sample made by closely arranging fibers and tape-like molecularly oriented molded bodies in one direction.
150. The stretching ratio of the molecularly oriented molded article used in the present invention is 5 to 80 times, preferably 10 to 50 times.

The degree of molecular orientation in the molecularly oriented molded product used in the present invention can be determined by an X-ray diffraction method, a birefringence method, a fluorescence polarization method, or the like. When the ultrahigh molecular weight polymer of the present invention is a drawn filament, for example, the degree of orientation according to the half value 11, which is described in detail in Yukichi Go, Teruichi Kubo: Industrial Chemistry Magazine, Vol. 39, p. 992 (1939), that is, the degree of orientation according to the formula The degree of orientation (F) defined by the formula % is 0.90 Above, especially 0.9
From the viewpoint of mechanical properties, it is desirable that the molecules be oriented so that the number of particles is 5 or more.

Furthermore, the ultra-high molecular weight ethylene a-
Molecularly oriented molded products of olefin copolymers also have excellent mechanical properties; for example, in the form of drawn filaments,
Elastic modulus of GPa or more, especially 300Pa or more, and 1.2G
It has a tensile strength of Pa or more, especially 165 GPa or more.

The impulse voltage breakdown value of the molecularly oriented molded product used in the present invention is 110 to 250 KV/m+s, preferably 1
50 to 220Kv/ll11. The impulse voltage breakdown value was measured using the same sample as in the case of dielectric constant, using a JIS type electrode with a yellow body (25 yarn diameter) on a copper plate, and increasing the voltage while applying a negative impulse in steps of 2 KV/3 times.

When the molecularly oriented molded product used in the present invention is a molecularly oriented molded product of an ultra-high molecular weight ethylene/α-olefin polymer, this molecularly oriented molded product has extremely excellent impact resistance, breaking energy, and creep resistance. It has the characteristic of The characteristics of the molecularly oriented molded products of these ultra-high molecular weight ethylene/α-olefin copolymers are expressed by the following physical properties.

The breaking energy of the molecularly oriented molded product of ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention is 8 hg-m.
72 or more, preferably 10 kg-m72 or more.

Further, the molecularly oriented molded product of the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention has excellent creep resistance. In particular, it has outstanding creep resistance at high temperatures, which corresponds to conditions that promote normal temperature creep, and when the load is 30% breaking load and the ambient temperature is 70°C,
The creep determined as elongation (%) after 90 seconds is 7% or less, especially 5% or less, and the creep rate (ε, 5ec-"l) after 90 seconds to 180 seconds is 4 X 10-'
see −' or less, especially 5 x 10 = sec −'
It is as follows.

Among the molecularly oriented materials used in the present invention, the molecularly oriented materials of ultra-high molecular weight ethylene/α-olefin copolymers have the above-mentioned room temperature properties, but in addition to these room temperature properties, they also have the following thermal properties. It is preferable that the material has both of these properties because the above-mentioned room temperature physical properties are further improved and the heat resistance is also excellent.

The molecularly oriented molded product of the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention has at least one crystal melting peak at a temperature at least 20°C higher than the original crystal melting temperature (Tm) of the copolymer. The heat of fusion based on (Tp) is 15% or more, preferably 20% or more, particularly 30% or more.

Ultra-high molecular weight ethylene copolymer original crystal melting temperature (T-
) can be determined by a method in which the molded body is completely melted, cooled to relax the molecular orientation in the molded body, and then heated again, a so-called second run in a differential scanning calorimeter.

To explain further, in the molecularly oriented molded product used in the present invention, there is no crystal melting peak at all in the above-mentioned crystal melting temperature range inherent to the copolymer, or even if it exists, it exists only as a very slight tailing. Only. The crystal melting peak (Tp) is generally within the temperature range To++20°C.
~TI+50℃, especially T++++20℃~Tm+100
It is usually expressed in the region of °C, and this peak (T
I)) often appears as a plurality of peaks within the above temperature range. That is, this crystal melting peak ("rp
) is the high temperature side melting peak (T p 1 ) in the temperature range Ta++35°C to Tm+100°C and the temperature range Tm
Low temperature side melting peak at +20℃~Tm+35℃ (
Tp2) and Tp2), and depending on the manufacturing conditions of the molecularly oriented molded product, Tp and T[J2 may further consist of a plurality of peaks.

These high crystal melting peaks (T p , T p z
) is said to significantly improve the heat resistance of molecularly oriented molded products of ultra-high molecular weight ethylene/α-olefin copolymers and contribute to strength retention or elastic modulus retention after high-temperature thermal history. Seem.

Further, it is desirable that the sum of the heat of fusion based on the high temperature side melting peak (Tp, ) in the temperature range Tm + 35°C - Ti + 20°C is 1.596 or more, particularly 3.0% or more, based on the total heat of fusion.

Furthermore, as long as the sum of the heat of fusion based on the high-temperature side melting peak (Tp 1) satisfies the above-mentioned value, if the high-temperature side melting peak (Tp 1) does not stand out as a main peak, that is, it is a small peak. Even if it becomes an aggregate or a broad peak, the heat resistance may be slightly lost, but the creep resistance is excellent.

The melting point and heat of crystal fusion in the present invention were measured by the following method.

The melting point was determined using a differential scanning calorimeter as follows.

A DSCII type (manufactured by PerkinElmer) was used as a differential scanning calorimeter. The sample was restrained in the orientation direction by wrapping about 3111 g around an aluminum plate measuring 4 mm x 4 mm and 0.2 mm thick. Next, the sample wrapped around an aluminum plate was sealed in an aluminum pan to serve as a running/running sample. Additionally, the empty aluminum pan that is usually placed in the reference holder was filled with the same aluminum plate used for the sample to maintain heat balance. First, the sample was held at 30°C for about 1 minute, then at 10°C.
The temperature was raised to 250° C. at a temperature increase rate of /min, and the melting point measurement at the first temperature increase was completed. Continue at 250℃ for 10
The sample was held at 30°C for 10 minutes, then the temperature was lowered at a rate of 20°C/min, and the sample was held at 30°C for 10 minutes.

Then, the second temperature increase was made to 250°C at a heating rate of 10°C/min.
At this time, the melting point measurement during the second temperature increase (second run) was completed. At this time, the maximum value of the melting peak was taken as the melting point. When it appears as a shoulder, a tangent is drawn at the inflection point immediately on the low-temperature side and the inflection point immediately on the high-temperature side of the shoulder, and the intersection is used as the excitation point.

In addition, the straight line (
Draw a perpendicular line to a point 20°C higher than the original crystalline melting temperature (TIIl) of the ultra-high molecular weight ethylene copolymer, which is determined as the main melting peak during the second temperature rise, and the area surrounded by these on the low temperature side. is based on the crystal melting (Tm) inherent to the ultra-high molecular weight ethylene copolymer, and the high temperature side part is based on the crystal melting (Tp) that expresses the function of the molecularly oriented molded product used in the present invention, The heat of fusion of each crystal was calculated from these areas.

In addition, the heat of fusion based on the melting of Tpl and T p 2 is determined by the perpendicular line from Ti + 20°C and Ts +
The part surrounded by the perpendicular line from +35℃ is the heat of fusion based on the melting of T I) 2, and the high; H side part is Tpl.
The heat of fusion was calculated in the same way based on the melting of .

The drawn filaments of the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention have a strength retention rate of 95% or more and an elastic modulus retention rate of 95% or more after being subjected to a heat history of 5 minutes at 170°C. % or more, especially 95% or more, and has excellent heat resistance that is completely unrecognizable in conventional drawn polyethylene filaments.

Method for producing molecularly oriented molded product of ultra-high molecular weight polyolefin As a method for obtaining the above-mentioned drawn ultra-high molecular weight polyolefin product having high elasticity and high tensile strength, for example, JP-A-56
-15408, JP 585228, JP 59-130313, JP 59-18761
The stretchability of ultra-high molecular weight polyethylene can be improved by making ultra-high molecular weight polyethylene into a dilute solution, or by adding a low molecular weight compound such as paraffin wax to ultra-high molecular weight polyethylene, as detailed in Publication No. 4, etc. An example of a method of improving the drawing ratio and stretching it to a high magnification can be exemplified.

Method for producing a molecularly oriented molded article of ultra-high molecular weight ethylene/a-olefin copolymer Next, the present invention will be explained below in the order of raw materials and production method for easy understanding.

Raw Materials The ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention is obtained by slurry polymerizing ethylene and an α-olefin having 3 or more carbon atoms in an organic solvent using a Ziegler catalyst. It will be done.

As the α-olefin having 3 or more carbon atoms, propylene,
Butene-1, Pentene-1,4-methylpentene-11
Hexene-1, heptene-11octene-1, etc. are used, and among these, butene-1,4-methylpentene-11hexene-1, octene-1, etc. are particularly preferred.

Such α-olefins are copolymerized with ethylene in the amount stated above per 1000 carbon atoms of the resulting copolymer. Further, the ultra-high molecular weight ethylene/α-olefin copolymer used as a base when producing the molecularly oriented product in the present invention should have a molecular weight corresponding to the above-mentioned intrinsic viscosity [η].

The α-olefin component in the ultra-high molecular weight ethylene/α-olefin copolymer used in the present invention is determined using an infrared spectrophotometer (manufactured by JASCO Corporation). Specifically, the absorbance at 1378 cm, which represents the bending vibration of the methyl group of the α-olefin incorporated into the ethylene chain, was measured using an infrared spectrophotometer, and this value was determined in advance by 13c nuclear magnetic resonance. Using the equipment, quantify the amount of α-olefin in the ultra-high molecular weight ethylene/α-olefin copolymer by converting it into the number of methyl branches per 1000 carbon atoms using a calibration curve created using a model compound. .

Production method In the present invention, when producing a molecularly oriented body from the ultra-high molecular weight ethylene/α-olefin copolymer, a diluent is blended into the copolymer. As such a diluent, a solvent for the ultra-high molecular weight ethylene copolymer or various wax-like substances having compatibility with the ultra-high molecular weight ethylene copolymer can be used.

Such a solvent has a boiling point higher than the melting point of the copolymer, more preferably 20°C higher than the melting point of the copolymer.
A solvent having a boiling point higher than that is used.

Specifically, such solvents include n-nonane, n-
- Decane, n-undecane, n-dodecane, n-tetradecane, n-octadecane or liquid paraffin, aliphatic hydrocarbon solvents such as kerosene, xylene, naphthalene,
Tetralin, butylbenzene, p-cymene, cyclohexylbenzene, diethylbenzene, pentylbenzene,
Aromatic hydrocarbon solvents such as dodecylbenzene, bicyclohexyl, decalin, methylnaphthalene, ethylnaphthalene or hydrogenated derivatives thereof, 1.1.2.2-Tetrachloroethane, pentachloroethane, hexachloroethane, 1.2.3- Examples include halogenated hydrocarbon solvents such as trichloropropane, dichlorobenzene, 1.2.4-trichlorobenzene, and bromobenzene, and mineral oils such as paraffinic process oils, naphthenic process oils, and aromatic process oils.

Further, as the wax as a diluent, specifically, an aliphatic hydrocarbon compound or a derivative thereof is used.

Such aliphatic hydrocarbon compounds are mainly composed of saturated aliphatic hydrocarbon compounds, and are usually compounds called paraffin waxes having a molecular weight of 2,000 or less, preferably 1,000 or less, more preferably 800 or less.

Examples of such aliphatic hydrocarbon compounds include n-alkanes having 22 or more carbon atoms such as tocosan, tricosane, tetracosane, and triacontane, mixtures of these with lower n-alkanes as main components, petroleum So-called paraffin wax separated and purified from ethylene or low-molecular-weight dipolymers obtained by copolymerizing ethylene with other α-olefins, medium-low pressure polyethylene wax, high-pressure polyethylene wax, ethylene copolymer wax, or Waxes obtained by reducing the molecular weight of polyethylene such as medium- and low-pressure polyethylene and high-pressure polyethylene by thermal degradation, oxides of these waxes, oxidized waxes modified with maleic acid, and waxes modified with maleic acid are used.

Examples of aliphatic hydrocarbon compound derivatives include, for example, one or more carboxyl groups, preferably one to two carboxyl groups, particularly preferably one carboxyl group, at the terminal or inside of an aliphatic hydrocarbon group (alkyl group, alkenyl group), A compound that combines functional groups such as a hydroxyl group, a carbamoyl group, an ester group, a meltcapto group, and a carbonyl group, and has a carbon number of 8 or more, preferably a carbon number of 12 to 50, or a molecular weight of 130 to 2000.
Preferably, 200 to 800 fatty acids, aliphatic alcohols, fatty acid amides, fatty acid esters, aliphatic mercaptans, aliphatic aldehydes, aliphatic ketones, etc. are used.

Examples of such aliphatic hydrocarbon compound derivatives include fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid, lauric alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol. Fatty acid amides such as caprinamide, lauramide, valmitinamide, and stearylamide, and fatty acid esters such as stearyl acetate are used.

The ultra-high molecular weight ethylene/α-olefin copolymer and diluent differ depending on their type, but -
:97-80 :20, especially 15:85-60:40
used in a weight ratio of If the amount of the diluent is lower than the above range, the melt viscosity will become too high, making melt kneading and melt molding difficult, and the resulting molded product will have a markedly rough surface, easily causing stretch breakage, etc. . On the other hand, if the amount of diluent exceeds the above range, melt-kneading becomes difficult.
Moreover, the stretchability of the molded product obtained becomes poor.

Melting crosstalk is generally 150~300℃, especially 170~2
It is carried out at a temperature of 70°C. If the temperature is lower than the above range, the melt viscosity will be too high and melt molding will be difficult; if the temperature is higher than the above range, the molecular weight of the ultra-high molecular weight ethylene α-olefin copolymer will decrease due to thermal degradation. death,
It becomes difficult to obtain a molded article having excellent high elastic modulus and high strength. The blending may be done by dry blending using a Henschel mixer V-type blender, etc.
Alternatively, it may be carried out using a single screw extruder or a multi-screw extruder.

Melt molding of a dope (spinning stock solution) consisting of an ultrahigh molecular weight m-ethylene/α-olefin copolymer and a diluent is generally performed by melt extrusion molding. Specifically, filaments for drawing are obtained by melt extruding the dope through a spinneret.

At this time, the molten material extruded from the spinneret may be drafted, that is, drawn in the molten state. The extrusion speed of the molten forged resin in the die orifice is 2v. The ratio of the winding speed V of the cooled and solidified undrawn material can be defined as a draft ratio by the following formula.

Draft ratio - ¥/Vo (2) This draft ratio varies depending on the temperature of the mixture, the molecular weight of the ultra-high molecular weight ethylene copolymer, etc., but is usually 3 or more, preferably 6 or more. can.

Next, the ultra-high molecular weight ethylene α obtained in this way
- Stretching the unstretched molded olefin copolymer. The stretching is carried out so as to effectively impart at least uniaxial molecular orientation to the unstretched molded article obtained from the ultrahigh molecular weight Fm ethylene/α-olefin polymer.

Stretching of an unstretched molded article obtained from an ultra-high molecular weight ethylene/α-olefin copolymer is generally carried out at a temperature of 40 to 160°C, particularly 80 to 145°C. Air,
Either steam or liquid medium can be used. However, as a heat medium, a liquid medium that is a solvent capable of eluting and removing the diluent described above and whose boiling point is higher than the melting point of the molded article composition, specifically, decalin, decane, kerosene, etc., is used. It is preferable to carry out the stretching operation in such a manner that the diluent described above can be removed, uneven stretching will not occur during stretching, and a high stretching ratio can be achieved.

The means for removing the diluent from the ultra-high molecular weight ethylene/α-olefin copolymer is not limited to the above-mentioned method, but may include a method of treating an unstretched material with a solvent such as hexane, heptane, hot ethanol, chloroform, or benzene, and then stretching it; A stretched product with high elastic modulus and high strength can also be obtained by removing the diluent in the molded product by treating the stretched product with a solvent such as hexane, heptane, hot ethanol, chloroform, or benzene.

The stretching operation can be performed in one stage or in multiple stages of two or more stages. The stretching ratio depends on the desired molecular orientation and the associated effect of increasing the melting temperature, but is generally between 5 and 5.
80 times, preferably 10 to 50 times.

In general, it is preferable to carry out the stretching operation in two or more stages, and in the -th stage, the stretching operation is carried out while extracting the diluent in the extrudate at a relatively low temperature of 80 to 120°C. From the second stage onward, it is preferable to stretch the molded body at a temperature of 120 to 160°C, and at a temperature higher than the first stage stretching temperature.

In the case of a uniaxial stretching operation, tension stretching may be performed between rollers having different circumferential speeds.

The molecularly oriented molded product thus obtained can be heat-treated under restrictive conditions if desired.

This heat treatment is generally carried out at 140-180°C, preferably at 15°C.
At a temperature of 0 to 175°C for 1 to 20 minutes, preferably 3 to 1
It can be done for 0 minutes. The heat treatment further advances the crystallization of the oriented crystal parts, shifts the crystal melting temperature to a higher temperature side, improves the strength and elastic modulus, and further improves the creep resistance at high temperatures.

In the present invention, a reinforcing material for an optical fiber cable is formed from a filament-like molecularly oriented body of the ultra-high molecular weight ethylene/α-olefin copolymer as described above. A conventionally known method is used to form the tension member.

The molecularly oriented molded product of ultra-high molecular weight ethylene/α-olefin copolymer can be used as a reinforcing material in the form of a monofilament or tape, which can be used along an optical fiber barcode or an aggregate of optical fiber barcodes, or as a multifilament. It is also possible to make a so-called pultrusion molded product in which a multifilament is impregnated with a resin along an optical fiber barcode or an aggregate of optical fiber barcodes. It can also be used in the form of a robe, string, or woven fabric made of multi-fibers, or it can be used as a prunol-john molded product by impregnating or coating a resin component with these braids or fabrics. can.

Effects of the Invention As mentioned above, in the present invention, ultra-high molecular weight ethylene α-
Since a molecularly oriented molded product of olefin copolymer is used as a reinforcing material for optical fiber cables, it has low water absorption and does not deteriorate the transmission characteristics of optical fiber coats.
It also has excellent creep resistance and impact resistance. Furthermore, it has excellent heat resistance compared to molecularly oriented molded products using ultra-high molecular weight polyethylene.

Hereinafter, the present invention will be explained using examples, but the invention is not restricted to the examples as long as the gist of the present invention is not exceeded.

Example 1 Polymerization of ultra-high molecular weight ethylene/butene-1 copolymer> An ultra-high molecular weight ethylene/butene-1 copolymer was slurry polymerized using a Ziegler catalyst and 1 g of n-decane as a polymerization solvent. . A mixed monomer gas containing ethylene and butene-1 in a molar ratio of 97.2:2.35 was continuously supplied to the reactor so as to maintain a constant pressure of 5 kg/c-. Polymerization was completed in about 2 hours at a reaction temperature of 70°C.

The yield of the obtained ultra-high molecular weight ethylene-butene-1 copolymer powder was 160 g, and the intrinsic viscosity [η] (decalin: 13
5° C.) was 8.2 d, l)/g, and the butene-1 content by infrared spectrophotometer was 1.5 per 1000 carbon atoms.

Preparation of stretched and oriented ultra-high molecular weight ethylene/butene-1 copolymer> 20 parts by weight of the ultra-high molecular weight ethylene/butene-1 copolymer powder obtained by the above polymerization and paraffin wax (melting point -69°C, molecular weight -490) and 80 parts by weight was melt-spun under the following conditions.

3.5- as a process stabilizer to 100 parts by weight of the mixture.
Di-tert-butyl-4-hydroxytoluene 0
．． 1 part by weight was added. Next, the mixture was melt-kneaded using a screw extruder (screw diameter = 25 mm, L/D-25, manufactured by Thermoplastics) at a set temperature of 1.90°C. Subsequently, the mixed melt was melt-spun using a spinning die with two orifice diameters attached to the extruder. The extrusion melt is 36 with an air gap of 180c+n.
The fibers were taken at a double draft ratio, cooled and solidified in the air, and undrawn fibers were obtained. Furthermore, the undrawn fibers were drawn under the following conditions.

Two-stage stretching was performed using a Godetstrol made by Ohdai. At this time, the heat medium in the first drawing tank is n-decane, and the temperature is 1
The heating medium in the second drawing tank was triethylene glycol, and the temperature was 145°C. The effective length of each tank was 50 cm.

During stretching, the rotational speed of the first godet roll is set to 0.
By changing the rotational speed of the third godet roll to 5 m/min, oriented fibers with a desired drawing ratio were obtained. The rotational speed of the second godet roll was appropriately selected within a range that allowed stable stretching. Almost all of the initially mixed paraffin wax was extracted into n-decane during stretching. Thereafter, the oriented fibers were washed with water, dried under reduced pressure at room temperature overnight, and subjected to measurement of various physical properties. Note that the stretching ratio was calculated from the rotational speed ratio of the first godet roll and the third godet roll.

Measurement of Tensile Properties> The elastic modulus and tensile strength were measured at room temperature (23° C.) using a new model DC5-50M tensile tester manufactured by Shimadzu.

At this time, the sample length between the clamps was 100 mm, and the tensile rate was 100 mm/min (100%/min strain rate). The elastic modulus was calculated using the slope of the tangent at the initial elastic modulus. The fiber cross-sectional area required for calculation was calculated from the weight, assuming the density as 0.960 g/ee.

<Tensile modulus and strength retention after heat history> The heat history test was conducted by leaving the material in a gear oven (Perfect Oven, manufactured by Nihai Seisakusho).

The sample had a length of about 3 m, and was folded over a stainless steel frame equipped with a plurality of pulleys at both ends to fix both ends of the sample. At this time, both ends of the sample were fixed to the extent that the sample did not sag, and no tension was actively applied to the sample. The tensile properties after the thermal history were measured based on the description of the measurement of the tensile properties described above.

Measurement of creep resistance〉 Creep characteristics were measured using a thermal stress strain measuring device TMA/5SI.
Using O (manufactured by Seiko Electronics Co., Ltd.), the sample length was 1 cn+
, the ambient temperature is 70℃, the load is 30% of the breaking load at room temperature.
It was carried out under accelerated conditions with a weight corresponding to . In order to quantitatively evaluate the amount of creep, the following two values were determined. In other words, the creep elongation after 90 seconds after loading (96) CR9o
and the average creep rate ε from 90 seconds to 180 seconds
(see −1) was calculated.

Table 1 shows the tensile properties of the obtained drawn and oriented fibers.

Table 1 The degree of orientation of the ultra-high molecular weight ethylene-butene-1 copolymer drawn filament (Sample-1) is 0.975, and its original crystal melting peak is 1.26.7°C. Tp relative to the total crystal melting peak area The proportion was 33.8%. In addition, the creep resistance is CR9゜-3.1%, E-3,03
It took 10-5 seconds. Furthermore, 170℃, 5
After a thermal history of 1 minute, the elastic modulus retention rate was 102.2% and the strength retention rate was 102.5%, showing no deterioration in performance due to the thermal history.

Also, the amount of work required to break the drawn filament is 10
, 3 kg-m/g, density is 0.973g/c
j, the dielectric constant was 2.2, the dielectric loss tangent was 0.024, and the -impulse voltage breakdown value was 180 KV/mm.

Preparation of Optical Fiber Cable> A thermoplastic resin film made of nylon 12 is provided on the outer peripheral surface of an optical fiber core wire made of GI type rough fiber via a silicone rubber buffer layer, and the outer diameter is 1! ll11, and on the outer circumferential surface thereof, drawn filaments of ultra-high molecular weight ethylene-butene-1 copolymer spun and drawn as described above were placed on the outer circumferential surface of the filament.
Six bundles of 1300 denier filaments (multifilaments) made up of 0 filaments bundled in parallel are arranged in symmetrical positions, and soft vinyl chloride is extruded and coated on the outer periphery to form a protective layer with a thickness of 0.5 mm. Then, optical fiber cables with an outer diameter of 2.4 mm were manufactured.

Example 2 Polymerization of ultra-high molecular weight ethylene/octene-1 copolymer Ethylene slurry polymerization was carried out using a Ziegler catalyst and 1 g of n-decane as a polymerization solvent.

At this time, 125 ml of octene-1 as a comonomer and 4 ON ml of hydrogen for molecular weight adjustment were added before starting the polymerization to start the polymerization. When the pressure of the reactor is 5
Continuously supply so as to maintain a constant pressure of kg / c-,
Polymerization was completed in 2 hours at 70°C. The yield of the obtained ultra-high molecular weight ethylene/octene-1 copolymer powder was 178 g.
Its intrinsic viscosity [η] (decalin, 135°C) is 10.
66 dfl/g.

The octene-1 comonomer content by infrared spectrophotometer is 10
The number was 0.5 per 00 carbon atoms.

<Preparation of drawn and oriented ultra-high molecular weight ethylene/octene-1 copolymer and its physical properties> A drawn and oriented fiber was prepared by the method described in Example 1.

Table 2 shows the tensile properties of the ultra-high molecular weight ethylene/octene-1 copolymer drawn fibers obtained.

Table 2 The degree of orientation of the ultra-high molecular weight ethylene/octene-1 copolymer drawn filament (Sample-2) is 0.978, and its original crystal melting peak is 131.1°C, and Tp relative to the total crystal melting peak area and Tpl percentages were 97.7% and 5.0%, respectively. The creep resistance of sample-2 filament is CR9, -2,0%, ε-9
, 50×10 −6 sec −1 . Mata, 170℃
, the elastic modulus retention after 5 minutes of thermal history is 108.2%,
The strength retention rate was 102.1%. Furthermore, the amount of work required to break the filament of sample-2 is 10.1 kg・m
/g-, density is 0.971g/aJ, relative permittivity is 2.2
, dielectric voltage contact is 0.031, impulse voltage breakdown value is 18
It was 5 KV/mm.

All other configurations were the same except that the tensile strength fiber layer was formed from six 1300-denier filament bundles made by bundling 130 ultra-high molecular weight ethylene octene-1 copolymer drawn filaments of Sample-2 in parallel. An optical fiber cable of Example 2 was manufactured using the same configuration as that of Example 1.

Comparative Example 1 Ultra-high molecular weight polyethylene (homopolymer) powder (intrinsic viscosity [η = 7.42 dN/g, decalin.

135°C): 20 parts by weight and paraffin wax (melting point -
69°C, molecular weight -490): 80 parts by weight of the mixture was melt-spun and drawn by the method of Example 1 to obtain drawn and oriented fibers.

Table 3 shows the tensile properties of the obtained drawn and oriented fibers.

Table 3 Ultra-high molecular weight polyethylene drawn filament (Sample-3)
The degree of orientation is 0.980, and the original crystal melting peak is 1
．． 35.1℃1. The ratio of Tp to the total crystal melting peak area was 8.8%. Similarly, the ratio of the high temperature side peak T p t to the total crystal melting peak area was 196 or less. Creep resistance is CH2O-11,
9%, ε-1,07×10-"5ee-'te.

In addition, the elastic modulus retention after 5 minutes of thermal history at 170°C is 80.
．． 4%, and the strength retention rate was 78.2%. Furthermore, the amount of work required for sample-3 to break is 10.2 kg-m/g, the density is 0.985 g/cJ, the dielectric constant is 2.3, the dielectric loss tangent is 0.030, and the impulse voltage breakdown value is 182 KV /
It was mm.

All other configurations were the same as in Example 1, except that the tensile strength fiber layer was formed of six 1300-denier filament bundles made by bundling 130 ultra-high molecular weight polyethylene filaments of Sample-3 in parallel. An optical fiber cable of Comparative Example 1 was prepared in the following manner.

Comparative Example 2 The structure of Comparative Example 1 was the same as that of Example 1 except that the tensile strength fiber layer was formed of a 450-denier aramid fiber (trade name: Kevlar-49) filament bundle. An optical fiber cable was created.

For both the optical fiber cables of Examples 1 and 2 and the optical fiber cables of Comparative Example 1.2, one was subjected to an accelerated humidification test for 5 months, and the other was stored in a vacuum container without an accelerated humidification test. When the signal transmission loss of each optical fiber cable was investigated, the results shown in Table 4 were obtained. The conditions for promoting humidification were a humidity of 100% and a temperature of 60°C.

Table 4 As is clear from Table 4 above, the optical fiber cables of Examples 1 and 2 have much lower water absorption rates than those of Comparative Example 2, and have excellent long-term signal transmission characteristics.

Further, the optical fiber cable of Example 1.2 and Comparative Example 1
．． Tensile property tests were conducted on both optical fiber cables. That is, a load giving a strain of 0.5% was applied to the optical fiber cable for 1 minute, and the residual strain and signal transmission loss after unloading were investigated, and the results shown in Table 5 were obtained. The tensile property test was conducted at a temperature of 23°C and a humidity of 55% R1.
I did it with +.

As is clear from Table 5 above, the optical fiber cable of Example 1.2 is far superior to the optical fiber cable of Comparative Example 1 in terms of residual strain under load, and as a result, it is also superior in signal transmission loss.

As explained above, certain ultra-high molecular weight ethylene α-
The optical fiber used as the olefin copolymer stretched oriented filament reinforcing material has no water absorption and has excellent creep resistance, so it has remarkable effects such as excellent signal transmission properties.

Table 5

Claims (1)

[Scope of Claims] 1) A superorganism having an intrinsic viscosity [η] of at least 5 dl/g and an average content of α-olefins having 3 or more carbon atoms of 0.1 to 20 per 1000 carbon atoms. A reinforcing material for optical fiber cables made of a molecularly oriented polymer of high molecular weight ethylene/α-olefin copolymer. 2) α-olefin is butene-1,4-methylpentene-1, hexene-1, octene-1 or decene-1
The reinforcing material for an optical fiber cable according to claim 1. 3) The reinforcing material for an optical fiber cable according to claim 1, wherein the content of α-olefin is on average 0.5 to 10 per 1000 carbon atoms.