JP2002258119A - Plastic optical cord - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a POF which has excellent dimensional stability and a low transmission loss. SOLUTION: This plastic optical cord is constituted by longitudinally attaching a fiber (A) to the outer periphery of a plastic coated optical fiber and bonding the fiber (A) by the resin layer. The fiber (A) is a core-and-sheath type composite fiber of which the core component is a molten anisotropic polyester and the sheath component is a flexible polymer containing 0 to 30 mass% molten anisotropic polyester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic optical cord, and more particularly, to a plastic optical cord which has excellent dimensional stability against load and heat and has small transmission loss.

[0002]

2. Description of the Related Art Conventionally, as an optical fiber, an inorganic silica-based optical fiber capable of performing excellent light transmission over a wide wavelength range has been known, and has been widely used mainly in a trunk system of optical communication. I have. On the other hand, plastic optical fibers, which are organic optical fibers, are also known, but are inferior in performance to quartz optical fibers, and have not reached widespread use.

However, in recent years, the performance of plastic optical fibers (hereinafter sometimes referred to as POFs) has been further improved, and optical communication networks have become widespread, and demands for wiring from homes to homes or buildings have increased. Attention has been paid to its large diameter, easy end face processing, and good handleability.

[0004] When used in such a wide variety of applications, the required performance becomes severe, and in particular, there is a demand for a small change in performance when a thermal or mechanical force, which is a weak point of POF, is applied. . Therefore, for example, Japanese Patent Application Laid-Open No. 58-18608 proposes to increase the heat resistance by forming a structure in which a protective layer is further provided around the sheath material. Further, for the purpose of improving the heat resistance and various characteristics of the POF itself, for example, JP-A-62-131206, JP-A-63-303304, and JP-A-2-68503.
JP, JP-A-5-11128, JP-A-6-20
No. 1270 proposes an improvement of a stretching / heat treatment method during POF production. However, the POFs obtained by these methods have poor dimensional stability and are not satisfactory in performance such as an increase in transmission loss.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a plastic optical cord having excellent dimensional stability and low transmission loss.

[0006]

That is, the present invention provides a plastic optical cord in which the outer periphery of a plastic optical fiber is vertically attached by a fiber (A), and the fiber (A) is bound by a resin layer. The fiber (A) is a core-sheath type composite fiber in which the core component is a flexible polymer containing 0 to 30% by mass of the melt-anisotropic aromatic polyester and the sheath component of the melt-anisotropic aromatic polyester. There is a plastic optical cord.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a POF constituting a plastic optical cord according to the present invention will be described. The material of the POF used for the core of the optical cord of the present invention is not particularly limited, but an amorphous transparent polymer is preferably used. As such polymers, methyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, adamantyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylate homopolymers such as naphthyl methacrylate, or these Copolymer of monomer and copolymerizable monomer, polycarbonate, polystyrene, styrene-
Methacrylate copolymers, deuterated polymers in which some or all of the hydrogen atoms of these polymers have been replaced by deuterium atoms, and the like can be used.

The methyl methacrylate copolymer used in the present invention is, assuming that the total amount of monomers as raw materials is 100% by mass, 70% by mass or more of methyl methacrylate and 30% by mass of another monomer copolymerizable with methyl methacrylate. It is preferably a copolymer of the following. Examples of other monomers copolymerizable with methyl methacrylate include methacrylic esters such as cyclohexyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, and 2,2,2-trifluoroethyl methacrylate. And monomers such as acrylates such as methyl acrylate and ethyl acrylate, and maleimide compounds such as N-cyclohexylmaleimide and N-isopropylmaleimide.

The method for producing the POF core wire can be produced by a known polymerization method, and is not particularly limited, but a continuous bulk polymerization or a continuous solution polymerization method can be employed from the viewpoint of preventing foreign matter from being mixed. preferable.

In the present invention, if necessary, a core-sheath type POF core wire may be formed by coating with a sheath material. As the sheath material, known materials can be used, and a homopolymer of a fluorine-based methacrylate, a copolymer of a fluorine-based methacrylate and a methacrylate-based monomer, a copolymer containing vinylidene fluoride as a main component, α -Fluoromethacrylate resins, mixtures thereof, and the like are preferably used.

Next, the plastic optical cord of the present invention will be described. The plastic optical cord of the present invention has a POF
It is characterized in that the outer periphery of the core wire is longitudinally attached by a fiber (A), and the fiber (A) is bound by a resin layer. The fiber (A) used in the present invention is a composite fiber whose core component is a melt-anisotropic aromatic polyester and whose sheath component is a flexible polymer. By vertically applying the fiber (A) to the POF core wire, a POF having excellent dimensional stability can be obtained.

The term "melt anisotropy" as used in the present invention means that the polymer exhibits optical anisotropy (liquid crystal properties) in a molten phase. For example, it can be recognized by placing the sample on a hot stage, heating it in a nitrogen atmosphere, and observing the transmitted light of the sample. The melt-anisotropic aromatic polyester constituting the core component according to the present invention has a repeating structural unit derived from an aromatic diol, an aromatic dicarboxylic acid, or an aromatic hydroxycarboxylic acid. Those comprising a combination of the indicated repeating units are preferred.

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Particularly preferred is a polymer comprising a combination of repeating structural units (5), (8), and (9) shown in Chemical Formula 1, more preferably a polymer corresponding to (5), An aromatic polyester in which the component (Q) in Chemical Formula 2 is 4-45 mol%.

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The preferred melting anisotropic aromatic polyester has a melting point (MP) of 250 to 350 ° C., more preferably 26 to 350 ° C.
0-320 ° C. The melting point as used herein means a differential scanning calorimeter (DSC: for example, TA300 manufactured by Mettler).
0) is the peak temperature of the main endothermic peak observed in (J)
IS K7121). Specifically, after taking 10 to 20 mg of a sample in a DSC device and enclosing the sample in an aluminum pan, nitrogen as a carrier gas is flowed at 100 mL / min.
Measure the endothermic peak when the temperature rises in minutes. If a clear endothermic peak does not appear in the first run depending on the type of polymer, raise the temperature to a temperature 50 ° C. higher than the expected flow temperature at a rate of 50 ° C./min, and hold at that temperature for 3 minutes or more. After complete melting, 5 ° C / min.
After cooling to 0 ° C., the endothermic peak may be measured at a heating rate of 20 ° C./min.

The melt anisotropic aromatic polyester used in the present invention includes polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyphenylene sulfide, and polyether ester ketone as long as the effects of the present invention are not impaired. , A fluorine resin or the like may be added. In addition, various additives such as inorganic substances such as titanium oxide, silica and barium oxide, carbon black, coloring agents such as dyes and pigments, antioxidants, ultraviolet absorbers and light stabilizers may be contained.

The flexible polymer used as the sheath component of the fiber (A) in the present invention has an optical anisotropy in the molten phase.
There is no particular limitation as long as it does not exhibit (liquid crystallinity), and examples thereof include thermoplastic polymers having a fiber-forming ability such as polyolefin, polyamide, polyester, polyarylate, polycarbonate, polyphenylene sulfide, polyester ether ketone, and fluororesin. . A preferred example is a polymer whose melting point is similar to that of the melt-anisotropic aromatic polyester as the core component.

More preferable sheath components are polyphenylene sulfide (PPS) and polyethylene naphthalate (PEN). These polymers are particularly suitable for the purposes of the present invention because of their high second order transition temperatures and high melting points.

In the present invention, by adding a melt-anisotropic aromatic polyester to the flexible polymer as the sheath component, it is possible to increase the strength of the sheath component and at the same time to enhance the adhesion to the core component. .

As the melt anisotropic aromatic polyester contained in the flexible polymer of the sheath component, the melt anisotropic aromatic polyester described for the core component can be used. in this case,
It may be the same or different from the core polymer. The content of the melt-anisotropic aromatic polyester is 0 to 30% by mass, and preferably 5 to 25% by mass. If it exceeds 30% by mass, bump-like irregularities are generated on the sheath, and the spinnability becomes poor.

It is preferable that the sheath component ratio in the fiber (A) of the present invention is 0.2 to 0.65. The sheath component is 0.
When it is less than 2, the core is easily exposed, and when it exceeds 0.65, the strength becomes insufficient. The sheath component ratio in the present invention is represented by D / (C + D) where C is the mass of the core component of the conjugate fiber and D is the mass of the sheath component. The sheath component ratio can also be determined from a micrograph of a fiber cross section.

The fiber (A) according to the present invention can be obtained by a known melt spinning method. The resulting fiber may be monofilament or multifilament.

Although the spun yarn can be used as it is for the obtained fiber (A), it is preferable to perform a heat treatment in order to further exert the effects of the present invention. By performing the heat treatment, the melt-anisotropic aromatic polyester undergoes solid-phase polymerization, so that the melting point can be increased and the strength, elastic modulus, and heat resistance can be improved.

The heat treatment can be performed in an atmosphere of an inert gas such as nitrogen, an atmosphere of an active gas containing oxygen such as air, or under reduced pressure. The heat treatment atmosphere has a dew point of -80 ° C
The following low humidity gases are preferred. Preferred heat treatment conditions include a temperature pattern in which the temperature is sequentially increased from the melting point of the core component −40 ° C. or lower to the melting point of the sheath component or lower. The heat treatment is preferably performed at a temperature equal to or lower than the melting point of the sheath component, but may be higher than the melting point of the sheath component as long as the sheath component does not stick.

Heat can be supplied by a method using a gaseous medium, a method using radiation by a heating plate, an infrared heater, or the like, an internal heating method using high frequency or the like. The shape of the treatment may be a scallop shape, a tow shape (for example, the treatment is performed on a metal net or the like), or the treatment may be performed continuously between rollers.

The plastic optical cord of the present invention can be obtained by vertically attaching the fiber (A) obtained by the above-described method to the outer periphery of the POF core and binding it with a resin layer. Examples of the binding method using a resin layer include a method in which the outer periphery of the POF and the fiber (A) is coated with a resin, a method in which a sheath component of the fiber (A) is thermally fused to form a resin layer, and the like.

The resin forming the resin layer according to the present invention is POF.
Any material can be used as long as it functions as a matrix resin for arranging and binding the fibers (A) around the core wire, and examples thereof include a thermoplastic resin, a thermosetting resin, and an ultraviolet curable resin. Thermosetting resins such as unsaturated polyester resins are preferably used.

As a method of coating the POF and the fiber (A) with a resin, a method of longitudinally adding the fiber (A) to the outer periphery of the POF core wire, impregnating the resin with a thermosetting resin, and then curing the resin is used. No. Here, it is extremely important to arrange the fibers (A) uniformly around the POF. Moreover, it is preferable to fix in a state of being arranged under high tension.
For this purpose, the amount of fibers to be arranged is designed according to the use of the optical cord, but the thickness is 0.1 to 1.0 mm.
It is important that they are arranged uniformly so that there is no unevenness in thickness. For that purpose, it is important to arrange the yarns in multiple layers with a guide and cover the outer periphery of the POF with high tension. Aramid fiber and melt anisotropic aromatic polyester fiber are
Although it has a high elastic modulus, fibrillation by a guide or the like occurs at the time of aligning the yarns, and pills and neps are included in the cord, which is not preferable. On the other hand, the fiber (A) used in the present invention can cover the POF with a high tension and a uniform thickness without generation of fibrils since the sheath component is composed of a flexible polymer.

Also, in the present invention, the fiber (A) is
After arranging on the outer periphery of the OF core wire, the sheath component of the fiber (A) may be thermally fused to form a resin layer and bind. According to this method, the fiber can be covered with the sheath component of the fiber (A).
Since a so-called tight-type optical cord that covers the core wire can be used, it is preferable in that the optical cord of the present invention can be reduced in diameter and a sufficient reinforcing effect can be imparted.

When the fiber (A) is manufactured by the above-described method, the ratio of the sheath component is 0.4 to 0.65.
It is more preferable to use the composite fiber of the above. If it is less than 0.4, it is necessary to perform heat fusion under high temperature and pressure, and the performance of the POF itself may be impaired. If it exceeds 0.65, the reinforcing effect may be insufficient. More preferably, a flexible polymer containing 5 to 30% by mass of a melt anisotropic aromatic polyester as the sheath component of the fiber (A) is preferably used. Thereby, even if the sheath component ratio is increased, a sufficient reinforcing effect can be provided. As the melt anisotropic aromatic polyester to be used, the same kind of polymer as the core component or a different kind of polymer may be used.

[0030]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In addition, the measured value in this example is a value measured by the following method. [Melt viscosity MV] Melting point + 20 ° C., shear rate r = 10
The measurement was performed using a Toyo Seiki Capillograph 1B under the conditions of 00 sec ^-1 . [Logarithmic viscosity ηinh] A sample was dissolved in pentafluorophenol at 0.1% by mass (60 to 80 ° C), and the relative viscosity (ηre was measured using a Ubbelohde viscometer in a thermostat at 60 ° C.
1) was measured and calculated by ηinh = ln (ηrel) / c. Here, c is the polymer concentration (g / dl). [Strength of elongation] Test length 20c according to JIS L 1013
m, initial load 0.09 cN / dtex, tensile speed 10 cm
The elongation at break was determined under the condition of / min, measured at five arbitrary points, and the average value was adopted. [Shrinkage Ratio] The shrinkage ratio when a sample having a sample length of 1 m was left in a constant temperature dryer at 100 ° C. for 24 hours was determined. [Tensile strength] A change of length (elongation) was measured every 1 m after applying a load of 0.5 kg to the sample and allowing the sample to stand for 24 hours. [Transmission loss] Incident angle NA = 0.1 by cutback method
Was measured for transmission loss at a wavelength of 650 nm.

Example 1 (1) Production of POF Polymethyl methacrylate as a core material, 55% by mass of methacrylic acid-2,2,2-trifluoromethyl as a sheath material and methacrylic acid-1,1,2,2- 30% by mass of tetrahydroperfluorodecyl, 15% by mass of methyl methacrylate
Was spun at 235 ° C. using vinylidene fluoride as a coating layer. 150 of this filament
Stretched 2.8 times at ℃, 1000μm in diameter, 10μ in sheath thickness
m, and a POF core wire having a coating layer thickness of 15 μm was obtained. (2) Production of Fiber (A) The melt-anisotropic aromatic polyester (MP =) in which the constitutional unit is represented by Chemical Formula 1 (5) as the core component and the structural unit (Q) represented by Chemical Formula 3 is 27 mol% 280 ° C, MV = 42Pa ・
s), and polyphenylene sulfide (MP = 281 ° C., MV = 110 Pa · s) was used as a sheath component. Using such a polymer, a nozzle diameter of 0.15 mm
Using a φ, 16-hole die, the amount of discharge was set so that the sheath component ratio became 0.4, and spinning was performed at 320 ° C. The obtained composite fiber was 110 dtex. The obtained fiber was heat-treated in a nitrogen atmosphere from 180 ° C. to 265 ° C. for 30 hours. The strength of the obtained fiber is 16.3 cN /
dtex and elongation were 3.6%. (3) Manufacture of plastic optical cord POF core wire at the center and fiber (A) on the outer circumference
Then, through the guide and the perforated plate, 20 of which are arranged in the second round, and then through the circumferential slit, 80% by mass of the vinyl ester resin and the unsaturated polyester resin 2
A curable resin consisting of 0% by mass was impregnated, and then the resin was cured. The ratio of the resin to the fiber was 42% by mass. The thickness of the coating layer is 80 to 110 μm and 1 k
In the production of m, there were no fluff or neps at all. The obtained cord had a shrinkage of 0.04%, a tensile strength of 0.06%, and a transmission loss of 142 dB / km. 0.5kg to this optical cord
Was measured and the transmission loss after standing for 24 hours was 145 dB / km. Table 1 shows the results.

[0032]

[Table 1]

Comparative Example 1 A plastic optical cord was prepared using only a POF core wire, and the same evaluation as in Example 1 was performed. Table 1 shows the results.

COMPARATIVE EXAMPLE 2 Nylon 12 is 0.6 m thick around the periphery of the POF core wire.
An optical cord having a coating layer of m was prepared and evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 2 The sheath component of the fiber (A) was PEN (MP = 265 ° C., MV =
Except for using 135 Pa · s), a composite fiber was produced in the same manner as in Example 1. The strength of the obtained fiber is 1
8.1 cN / dtex and elongation were 38%. The obtained fiber (A) is longitudinally attached to the outer periphery of the POF core wire in the same manner as in Example 1, and then is passed through an orifice heated to 300 ° C. to thermally fuse the sheath component of the composite fiber to obtain an optical cord. It was created. Table 1 shows the results.

Comparative Example 3 A fiber consisting of only the melt-anisotropic aromatic polyester was spun to obtain a fiber of 112dex / 16 filaments. The fiber obtained by heat-treating the obtained fiber under the same conditions as in Example 1 had a strength of 24.3 cN / dtex and an elongation of 4.2%. An attempt was made to coat the obtained fiber with a POF core wire under the same conditions as in Example 1. However, pills made of fibrils accumulated on the guide and the perforated plate, which were carried into the cord, and troubles continued.

[0037]

According to the present invention, a plastic optical cord having excellent dimensional stability and low transmission loss can be obtained.

Claims (4)

[The claims] 1. A plastic optical cord in which an outer periphery of a plastic optical fiber core is vertically attached by a fiber (A), and the fiber (A) is bound by a resin layer, and the fiber (A) is , The core component is a melt anisotropic aromatic polyester,
A plastic optical cord whose core component is a core-sheath type conjugate fiber composed of a flexible polymer containing 0 to 30% by mass of a melt anisotropic aromatic polyester. 2. The plastic optical cord according to claim 1, wherein the sheath component of the fiber (A) is polyphenylene sulfide. 3. The plastic optical cord according to claim 1, wherein the sheath component of the fiber (A) is polyethylene naphthalate. 4. The plastic optical cord according to claim 1, wherein the resin layer comprises a sheath component of the fiber (A).