JP2002055243A - Plastic optical fiber cable, plastic optical fiber cable with plug, their fixing method and optical transmission parts - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide excellent adhesion between a POF strand and a covering material,
Provided is a plastic optical fiber cable having a coating layer made of a polyamide resin having excellent environmental resistance. SOLUTION: A plastic optical fiber is heated to 105 ° C.
When the heat shrinkage in the axial direction of the plastic optical fiber is 1.5% or less when heat-treated at 24 ° C. for 24 hours, and the plastic optical fiber cable provided with the polyamide resin coating layer is heat-treated at 105 ° C. for 100 hours. Is less than 1 / 10,000 or less of the total length of the plastic optical fiber cable, the transmission loss after heat treatment at 105 ° C. for 1000 hours is 0.1 dB / m or less, and the plastic optical fiber strand and the coating layer A plastic optical fiber cable having a pull-out strength of 15 N or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic having a polyamide resin coating layer having excellent heat resistance, flame retardancy and chemical resistance of about 100.degree. The present invention relates to an optical fiber cable.

[0002]

2. Description of the Related Art Plastic optical fibers (hereinafter referred to as POF)
That. ) Has characteristics such as inexpensiveness, light weight, flexibility, large diameter, etc., though the transmission distance is shorter than that of quartz-based optical fibers, and is suitable for short-distance communication applications such as lighting applications, FA, OA, and LAN. Practical in the field. Most of such POFs have a core-sheath structure in which polymethyl methacrylate (PMMA) is used as a core material and a resin material having a lower refractive index than the core material is disposed around the core material. As the core material, in addition to polymethyl methacrylate, various amorphous resin materials such as polycarbonate and polystyrene have been proposed. However, since the material is inferior in light transmission, material price, and durability, it is not suitable as a core material for POF. Polymethyl methacrylate has become popular as a preferred one.

[0003] In recent years, in view of the spread of car navigation systems, an increase in the amount of communication information due to the concept of introducing an ITC / ETC system, and the like, reduction in the weight of harness cables, construction of inexpensive communication systems, and the like. From
The POF using polymethyl methacrylate as a core material is being developed for use in automobiles. At present, the upper limit temperature of practical use of POF is about 80 ° C., and it is used only in a place where the environmental conditions are relatively low and the environmental conditions are mild, avoiding severe environmental points inside the automobile. To further expand the range of use, it is necessary to improve the heat-resistant upper limit temperature of POF.

Therefore, many proposals have been made with the aim of improving the heat-resistant upper limit temperature by selecting and improving the sheath material and the coating layer material using PMMA having excellent transmission characteristics as a core material.
For example, JP-A-61-103107, JP-A-61-103107
-240205 and JP-B-2-50442 propose a POF using a copolymer composed of α-fluoroacrylic ester as a sheath material having high heat resistance. JP-A-11-16
No. 0552 proposes a POF and a POF cable using a vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer and a vinylidene fluoride / hexafluoropropylene copolymer as a sheath material. The coating layer is also disclosed in JP-A-61-2380.
No. 02 proposes a POF cable provided with a high heat resistance and a method stability by providing a coating of a polyolefin having a crosslinked structure formed by silanol condensation.

[0005]

The POF cable for communication used in automobiles is used in summer and in an environment close to a high temperature body such as an engine, so that it has heat resistance, heat-resistant dimensional stability, oil and electrolyte. In addition, in an environment where a flammable material such as gasoline is present, it is required that the POF and the coating layer be strongly adhered from the viewpoint of protecting the POF against vibration, in addition to chemical resistance and flame retardancy. For this reason, a polyamide resin such as nylon is preferred as the coating layer, and polyamide resins such as nylon 11 and nylon 12 are also used in POF cables for automobiles currently used. However, such a POF cable in which a bare POF wire is simply coated with a polyamide resin has the following problems.
When used at a high temperature of 05 ° C. for a long time, the POF wire is drawn into the coating layer, so-called pistoning occurs, the heat-resistant transmission loss increases, and the transmission loss under the heat-resistance increases greatly. Had the problem of becoming

Further, in the case of the POF having the above-mentioned copolymer of α-fluoroacrylic acid ester as a sheath material, the sheath material itself is non-crystalline and has a high glass transition temperature of 110 ° C. or higher. Although the wire shows stable transmission characteristics even at a high temperature of about 105 ° C., when a sheath layer of a polyamide resin is provided outside this sheath, the shrinkage of the POF wire cannot be sufficiently suppressed by the sheath layer. And the dimensional stability during heat resistance was insufficient.

Further, a sheath made of vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer or vinylidene fluoride / hexafluoropropylene copolymer is used, and a coating layer such as polyamide resin or vinyl chloride resin is formed. Although a high heat resistance of about 110 ° C. and dimensional stability can be obtained, the sheath material has a low glass transition temperature of room temperature or lower and is a soft material. It is necessary to apply a protective layer or pre-coating layer that thermally protects the strands, and even if the coating layer is applied, if it is subjected to mechanical action at high temperatures, the shape of the sheath material will be deformed and the optical characteristics will deteriorate. Therefore, there is a possibility that a problem such as a loosened portion of the connector portion may occur.

In the case of forming a coating layer of a polyolefin having a crosslinked structure introduced by silanol condensation, a POF strand is coated with an unreacted water-crosslinked polyolefin precursor and then treated with warm water or hot water to relax the POF cable. It is necessary to perform a crosslinking treatment. For this reason, the effect of improving the heat shrinkage characteristics of the POF wire and the morphological stability of the crosslinked polyolefin are combined, so that P can be used at about 110 ° C.
Although an OF cable can be obtained, when hot water or hot water treatment is performed, the morphological change of the POF strand and the coating layer is accompanied, so that the adhesion between the POF strand and the coating layer is higher than that of a normal polyolefin-coated POF cable. However, there is a problem that sufficient adhesion cannot be ensured in applications where strong adhesion is required from the viewpoint of vibration resistance when used for automobiles. Further, a coating layer made of polyolefin cannot obtain the same characteristics as a coating layer made of a polyamide resin in terms of flame retardancy and chemical resistance.

Accordingly, an object of the present invention is to provide a POF cable suitable for an automobile having a polyamide resin coating layer having excellent heat resistance, flame retardancy and chemical resistance of about 100 ° C. is there.

[0010]

That is, the plastic optical fiber cable according to the present invention has a core material composed of a polymer containing polymethyl methacrylate as a main component, and a structural unit composed of α-fluoroacrylic ester outside the core material. Of a plastic optical fiber cable having a sheath layer made of a polymer having the same and having a coating layer made of a polyamide resin on the plastic optical fiber wire, the plastic optical fiber wire when the plastic optical fiber wire is heat-treated at 105 ° C. for 24 hours. The heat shrinkage in the axial direction is 1.5% or less, and when the plastic optical fiber cable provided with the coating layer of the polyamide resin is heat-treated at 105 ° C. for 100 hours, the pistoning is performed with respect to the entire length of the plastic optical fiber cable. 1 / 10,000 or less, heat treatment at 105 ° C for 1000 hours 0.1d increase in transmission loss after the
B / m or less, and the pull-out strength between the plastic optical fiber and the coating layer is 15 N or more.

Further, a plastic optical fiber cable with a plug according to the present invention is characterized in that a plug is connected to one or both ends of the plastic optical fiber cable as described above.

Further, the optical transmission component of the present invention is characterized in that the coating layer of the plastic optical fiber cable or the plastic optical fiber cable with a plug as described above is melted by heat and adhered to another component. is there.

In addition, the method of fixing a plastic optical fiber cable according to the present invention is to heat-melt the coating layer of the plastic optical fiber cable or the plastic optical fiber cable with a plug as described above, and to bond it to other parts. It is a feature.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The POF wire of the present invention has a core-sheath structure P using a polymer mainly composed of PMMA as a core material.
OF. In the present invention, as a core material, a component other than methyl methacrylate is used as a copolymerization component as a PMM.
It is also possible to use those introduced in A, or a mixture of PMMA and another polymer. As the copolymerization component, materials that have been proposed as core materials for POF such as methacrylates and acrylates can be appropriately selected. In the present invention, P
From the viewpoint of obtaining OF, it is preferable to use, as the core material, a polymer having a structural unit composed of methyl methacrylate of 90 mol% or more, and particularly preferably, a polymer using a homopolymer of methyl methacrylate as the core material. It is.

The polymer constituting the core material of the present invention is 125
An azoalkane-based thermal polymerization initiator as an initiator is polymerized by continuous bulk polymerization using a low boiling point mercaptan as a chain transfer agent at a temperature of ~ 135 ° C, and then supplied to a devolatilizing extruder to obtain unreacted monomers and mercaptan. It is preferable that the polymer is manufactured by removing such factors, since a polymer suitable as a core material having high heat resistance and little deterioration of transmission loss in a high-temperature environment can be obtained. By performing polymerization in such a polymerization system, the stereoregularity of the polymer used as the core material is improved, the heat-resistant transmission characteristics as POF, and the dimensional stability in a high-temperature environment can be improved. Can be further increased.

For example, when PMMA is used as the core material, 2,2′-azobisisobutyronitrile, dimethyl 2,2′-azobisisobutyrate (V-
601), at least one kind of 2,2′-azobis (2,4,4-trimethylpentane) (VR-110) is used as a chain transfer agent using normal butyl mercaptan, and 125
It is preferable that the polymerization is carried out at a temperature of from 0 ° C. to 135 ° C. until the polymerization rate reaches 40 to 50% as a residence time of about 4 hours, and then supplied to a devolatilizing extruder to obtain a polymer.

The unreacted monomer, dimer (dimer), and residual mercaptan present in the polymer used as the core material cause a reduction in the heat resistance of the POF. Hereinafter, 0.
It is preferable that the content be 3% by weight or less.

As the sheath material used in the present invention, it is necessary to use a polymer having a structural unit composed of α-fluoroacrylic acid ester. Since this polymer has a fluorine atom at the α-position, it has a higher glass transition temperature than a polymer composed of a (meth) acrylate having the same ester group, and POF having a polymethyl methacrylate core material By using as a sheath material, it becomes possible to make the heat resistance temperature of POF about the glass transition temperature of the core material. In order to exhibit sufficient heat resistance and dimensional stability at about 105 ° C. for automobiles, which are main applications of the POF cable of the present invention, the glass transition temperature of the polymer constituting the sheath material must be higher than the practical temperature. Preferably, the temperature is usually set to 120 ° C. or higher. Further, by using the polymer constituting the sheath material in a state in which the micro-brown motion of the main chain is suppressed, stable transmission characteristics at a high temperature for a long period of time are maintained, and at the same time, POF described later is used.
It becomes possible to reduce minute structural defects while maintaining the orientation of the sheath material in the process of reducing the shrinkage of the strand, and it is possible to further improve the transmission under high temperature and the dimensional stability. .

In the present invention, the α-fluoroacrylic ester constituting the polymer used as the sheath material is preferably α-methyl methyl acrylate (alone) from the viewpoint of the glass transition temperature and the thermal decomposition resistance (prevention of depolymerization). Glass transition temperature of polymer 140 ° C.), α-fluoroacrylic acid 2,
2,2-trifluoroethyl (glass transition temperature of homopolymer 120 ° C.), α-fluoroacrylic acid 2,2,3
3,3-pentafluoropropyl (homopolymer glass transition temperature: 95 ° C.) is preferred, and one or more of these α-fluoroacrylates can be used as a component of the polymer.

Further, the polymer constituting the sheath material of the present invention includes, in addition to a polymer having a structural unit composed of α-fluoroacrylic acid ester, methyl acrylate and (meth) from the viewpoint of improving thermal decomposition resistance. It is preferable to use acrylic acid or the like.

The polymer having such a structural unit composed of α-fluoroacrylate has a refractive index of 1.38.
It is preferably in the range of ~ 1.42. This is because most of the commercially available POFs made of PMMA as a core material have an NA of about 0.5. When connecting to these POFs or connecting to light receiving and emitting elements based on these POFs. This is because, in order to suppress an increase in coupling loss due to the difference in NA, it is preferable to design the same as the NA of a conventionally used POF. The numerical aperture (N
A: Numerical Aperture refers to the refractive index (n _core ) of the _core material and the refractive index (n _{c lad} ) of the sheath material, as in the case of the numerical aperture (NA) generally used in the optical field, and NA = (n _core). ^2- n _clad ² ) A parameter defined by ^0.5 . When PMMA is used as the core material, the refractive index of the sheath material when NA is 0.5 is about 1.40.

As described above, the NA of the POF can be designed by adjusting the refractive index of the sheath material.
In connection with the OF, compatibility can be provided, and the PO connected to the optical element and the housing of the conversion unit in the E / O, O / E conversion unit placed in a high temperature environment.
It can be suitably used as a relay wiring cable used for relaying F and protecting an optical element that is vulnerable to dirt and mechanical damage.

In the POF strand of the present invention, a protective layer made of a thermoplastic resin may be provided as the outermost layer of the POF strand for the purpose of improving mechanical properties and chemical resistance. The protective layer is not particularly limited and can be appropriately selected from those usually used as a protective layer for POF. Vinylidene fluoride, vinylidene fluoride / tetrafluoroethylene, polycarbonate, polymethyl methacrylate And the like are preferable because the shaping temperature is close to that of the core material and the sheath material and it is possible to carry out the spinning integrally with the melt composite spinning.

The POF wire having the above structure is
It is necessary that the heat shrinkage in the axial direction of the POF strand when heat-treated at 105 ° C. for 24 hours is 1.5% or less. This is because when the heat shrinkage exceeds 1.5%, the POF cable can be used even if a coating layer made of polyamide resin is formed.
When used at a high temperature of 05 ° C. for a long time, shrinkage of the POF wire cannot be completely suppressed by the coating layer, and pistoning occurs. The heat shrinkage in the axial direction of the POF strand is preferably 1% or less, in order to further improve the dimensional stability of the POF strand under heat resistance and to further reduce the pistoning of the POF. Preferably 0.5%
It is as follows.

[0025] The POF strand satisfying such heat shrinkage characteristics can be obtained, for example, by subjecting the POF strand itself to heat treatment or relaxation treatment to reduce the heat shrinkage, or to heat treatment after coating a coating resin such as a water-crosslinked polyolefin resin. Alternatively, it can be obtained by a method of reducing the heat shrinkage by performing a relaxation treatment. In the present invention, since the coating layer is a polyamide resin having good dimensional stability even at a high temperature, the latter method of lowering the heat shrinkage of the POF wire after coating with a water-crosslinked polyolefin resin or the like, compared to the former. Since it is necessary to lengthen the processing time or to tighten the processing conditions, and other characteristics of the POF wire tend to decrease,
A method of performing a heat treatment or a relaxation treatment on the POF strand itself is preferable.

The temperature of the heat treatment and the relaxation treatment is 90 ° C.
The temperature is preferably from about to 120 ° C. This is because, when the temperature is higher than 120 ° C., the stretch orientation generally applied for the purpose of imparting strength in the method of producing POF tends to decrease,
If the temperature is lower than 90 ° C., heat treatment for a very long time is required in order to obtain desired heat shrinkage properties, or relaxation treatment tends to be required many times. Also,
The temperature of the heat treatment and the relaxation treatment is performed at a temperature equal to or lower than the lower one of the glass transition temperature of the core material and the glass transition temperature of the sheath material.
It is preferable because it is possible to improve the heat shrinkage property and obtain a strand having excellent mechanical properties.

As the method of the heat treatment and the relaxation treatment, water,
The heating can be performed by heating the POF wire with a heating medium such as steam or a heating gas, or by passing the POF wire through the heating medium and changing the supply and discharge speeds of the POF wire before and after the furnace. When performing such processing, P
By applying a tension of several hundred gf to the OF wire, the preservability of the stretch orientation can be improved, which is preferable.

The polyamide resin used as the coating layer for coating the POF strand in the present invention includes nylon 66,
Nylon 6, Nylon 11, Nylon 12, Nylon 6
12, nylon 621, various copolymerized nylons having these structures, nylon elastomers, and copolymers and mixtures thereof. Above all, it has a relatively low melting point, can exhibit high adhesion to the POF strand without deteriorating the properties of the POF strand of the present invention, has low water absorption, and has dimensional stability during heat resistance. It is preferable to use a material containing nylon 11 or nylon 12 as a main component from the viewpoint of good properties.

In the coating layer of the present invention, various dyes, pigments, phosphoric acid esters,
A commonly used flame retardant such as an inorganic hydroxide, a halogen compound or a triazine compound may be mixed with a polyamide resin. As a flame retardant, the amount of addition is small, the flexibility of the POF cable is not impaired, the generation of toxic gas at the time of combustion is small, and there is no transfer to the POF wire and there is no penetration. Materials are preferred.

Further, in the present invention, by adding an organic acid or an organic acid anhydride to the coating layer, the adhesion between the POF wire and the coating layer can be further improved. The amount of the organic acid or organic acid anhydride to be added is preferably 0.2 to 10% by weight, more preferably 0.5 to 5% by weight, based on the resin constituting the coating layer. If the amount of addition is less than 0.2% by weight, the desired improvement effect tends not to be obtained, and if it exceeds 10% by weight, the fluidity of the resin decreases and the smoothness of the surface of the POF cable tends to decrease. It is because there is. Organic acids and organic acid anhydrides to be used include:
Examples include acrylic acid, methacrylic acid, maleic acid, fumaric acid, salicylic acid, succinic acid, glutaric acid, phthalic acid, and anhydrides thereof.

In the present invention, a plurality of coating layers may be formed. For example, various physical properties of the POF cable can be adjusted by using a polyamide resin having different characteristics for each coating layer.

The coating layer can be formed by a method generally used as a method of forming a POF wire into a cable. The method of forming the coating layer using a crosshead die is described in the present invention. That fully exhibited the effect of
It is preferable because an OF cable can be obtained.

The POF cable having a coating layer formed on the outside of the thus obtained POF wire must have a pull-out strength of 15 N or more between the POF wire and the coating layer. This is because by setting the pull-out strength to 15 N or more, the adhesion between the POF strand and the coating layer can be sufficiently increased, and the connector part firmly fixed by mechanical action such as vibration. Breakage of the POF strand at the end or the like can be prevented. The pull-out strength is preferably 25N or more, more preferably 40N or more.

Further, in the POF cable of the present invention, it is necessary that the pistoning of the POF wire used for the communication use be within a range that does not deteriorate the light receiving and emitting characteristics, and the pistoning when heat-treated at 105 ° C. for 100 hours. Needs to be 1 / 10,000 or less with respect to the entire length of the POF cable. 1/1000 for pistoning
By setting it to 0 or less, the pistoning at each light receiving / emitting end of the POF link can be made 0.5 mm or less,
The total length of the light receiving end and the light emitting end can be set to 1 mm or less, and it is possible to allow the position accuracy and tolerance within the range. This pistoning is preferably 1/20000 or less, and by doing so, even if the device is continuously used at 100 ° C. for several years or more, deterioration of the light receiving and emitting characteristics of the POF can hardly occur.

The increase in the transmission loss of the POF cable of the present invention during heat resistance is required to be 0.1 dB / km or less when subjected to heat treatment at 105 ° C. for 1000 hours, and preferably 0.1 dB / km. 05 dB or less, more preferably 0.03 dB or less. This increase in transmission loss is reduced by 0.1
By setting it to dB / km or less, sufficient heat loss characteristics can be obtained even at a high temperature of 105 ° C.

In particular, E /
When used as a POF cable connected to the housing of the optical element and the conversion unit in the O, O / E conversion unit,
With the above-mentioned characteristics of increasing the pistoning and the heat transmission loss, there is almost no deterioration of the characteristics under a heat-resistant environment, and the device can be used with high reliability.

The POF cable of the present invention can be used as a POF cable with a plug, a point sensor or the like by providing a connection plug at one end or both ends. As the plug to be used, a plug that is usually used as a plug of a POF cable can be used according to the purpose.

Further, when the POF cable of the present invention is connected to another component such as a connector, the portion of the component to be connected to the POF cable is formed of the same polyamide resin as the coating layer, thereby connecting the POF cable and the component. After that, it becomes possible to irradiate a laser beam, an electron beam, or the like, to thermally fuse the coating layer and the component to fix them. In this way P
By fixing the OF cable and components, the normal P
The crimping process, which is a method of fixing the OF cable, is not required, and the POF cable and the component can be firmly connected.

[0039]

The present invention will be described below with reference to examples. In addition, about the evaluation method in the Example of this invention, it implemented by the following method.

(Transmission characteristics) Measurement wavelength 650 nm, excitation N
Under the condition of A = 0.1, it was measured by a 25 m-5 m cutback method.

(Quantitative Determination of Residual Monomer, Residual Mercaptan and Dimer in the Core Material) The core material polymer is dissolved in acetone, the solution is analyzed by pyrolysis gas chromatography, and a calibration curve previously determined is used. Then, the content in the polymer was quantified.

(Evaluation of Heat Shrinkage Rate of Wire) A wire having a distance between test lengths of 1 m was suspended in a dryer at 105 ° C., the distance between the test lengths after 24 hours was measured, and divided by the test length. The contraction rate of the strand in the fiber axis direction was determined.

(Coating pull-out strength) Using the fixing jig shown in FIG. 1, a tensile tester was used to grip the strand portion of the cable, and the maximum value of the tensile strength was measured at a measuring length of 30 mm to pull out the coating. Strength.

(Evaluation of Gasoline Resistance) A cable having a test length of 25 m was immersed in gasoline at an environment temperature of 25 ° C. for 1000 hours, and evaluated by a transmission loss value after immersion.

(Evaluation of Pistoning) A cable having a test length of 200 mm was heat-treated at 105 ° C. for 100 hours, the difference in length between the treated cable and the strand was measured, divided by the test length, and the ratio to the total cable length was measured.

(Evaluation of Flame Retardancy) Twenty samples were evaluated according to the measurement method of DIN72551-5, and when the number of passed samples was 18 or more, the samples were judged as acceptable, and those with less than 18 were judged as unacceptable.

[0047]

Example 1 100 parts by weight of methyl methacrylate, 2,
Dimethyl 2'-azobisisobutyrate 0.01 part by weight and normal butyl mercaptan 0.15 part by weight were polymerized at a polymerization temperature of 12
Continuous continuous bulk polymerization was carried out at 5 ° C. for 4 hours, and the resulting polymerization solution was fed to a degassing extruder to remove low-boiling components such as unreacted monomers and mercaptan to remove polymethacrylic acid for the core material. Methyl was made. This core material and α-methyl acrylate / α-fluoroacrylate 2,2,2
A strand obtained by melt-composite spinning using a trifluoroethyl copolymer (15/85 mol%) as a sheath material is stretched twice in the fiber axis direction in a hot air oven at 140 ° C.
C. through a hot air oven to obtain a core-sheath POF having a diameter of 1 mm and a sheath thickness of 10 μm.

The refractive index of the sheath used for this POF strand was 1.39, and the glass transition temperature measured by DSC was 12
At 0 ° C., the residual monomer, MMA dimer, and residual mercaptan in the core material were 0.25% and 0.15% 3 ppm, respectively, as measured by pyrolysis gas chromatography.

The obtained POF wire was heated at 105 ° C. and 300 g.
Heat treatment was performed for 24 hours under the tension of f. This POF wire was coated with nylon 12 resin (manufactured by Daicel Huls: nylon 12) with a crosshead die set at 220 ° C. to produce a POF cable having a diameter of 1.5 mm. The coating layer of this POF cable was stripped, and the thermal shrinkage of the POF wire was measured to be 0.7%. Also, P
Various evaluations of the OF cable were performed, and the results are shown in Table 1. The obtained POF cable is a POF cable which is less deteriorated in transmission characteristics under heat-resistant environment, has less pistoning, has strong adhesion between the POF wire and the coating layer, has excellent gasoline resistance, and is excellent in use in automotive applications. Was

[0050]

Example 2 100 parts by weight of nylon 12 as a coating material
A POF cable was produced in the same manner as in Example 1 except that 1 part by weight of maleic anhydride was added and kneaded to obtain a kneading resin. Various characteristics of the obtained POF cable were evaluated, and the results are shown in Table 1.

[0051]

Embodiments 3 to 6, Comparative Examples 1 and 2 Configuration of POF strand, P
A POF cable was produced in the same manner as in Example 2 except that the conditions of the OF wire low heat shrinkage treatment were as shown in Table 1. Various characteristics of the obtained POF cable were evaluated, and the results are shown in Table 1. In the case where the POF strand has a large heat shrinkage as in Comparative Example 1, the pistoning and the POF
The heat shrinkage of the cable itself was large, and the reliability during heat-resistant use was insufficient.

[0052]

Examples 7 and 8 Same as Example 2, except that 20 parts by weight of melamic acid isocyanate and 1 part by weight of maleic anhydride were added and kneaded as a flame retardant to 100 parts by weight of nylon 12. To produce a POF cable. Various characteristics of the obtained POF cable were evaluated, and the results are shown in Table 1. Further, when the flame retardancy test of this POF cable was performed, all 20 samples passed.

[0053]

Comparative Examples 3 and 4 A POF cable was produced in the same manner as in Comparative Example 1 except that a water-crosslinked polyethylene resin was coated as a coating resin. This POF cable is immersed in hot water of 98 ° C. for 3 hours to simultaneously carry out the water crosslinking reaction of the coating resin and the heat treatment of the POF strand, thereby obtaining a water-crosslinked polyethylene-coated POF.
Was prepared. Various characteristics of the obtained POF cable were evaluated, and the results are shown in Table 1. This POF cable is
The gasoline resistance was inferior to the polyamide resin coated.

[0054]

Comparative Example 4 The diameter of the POF cable of Comparative Example 3 was 1.3 m.
POF produced by changing the thickness of the coating layer so as to obtain m
Nylon 12 was coated as a secondary coating on the outside of the cable to produce a two-layer coated cable having a POF cable diameter of 1.5 mm. Various characteristics of the obtained POF cable were evaluated, and the results are shown in Table 1. This POF cable is
The adhesion between the water-crosslinked polyethylene of the primary coating layer and the nylon 12 of the secondary coating layer was low, and in the pull-out test, peeling occurred between the primary coating layer and the secondary coating layer.

[0055]

[Table 1] In the table, compound abbreviations indicate the following compounds, respectively. α3FA / αFMe: α-fluoroacrylic acid 2, 2,
2-trifluoroethyl / α-methyl methyl acrylate copolymer (85/15 mol%) α3FA / α5FA / α
3FMe: α-fluoroacrylic acid 2,2,2-trifluoroethyl / α-fluoroacrylic acid 2,2,3,
3,3-pentafluoropropyl / α-methyl fluoroacrylate copolymer (60/10/30 mol%) VdF / TFE: vinylidene fluoride / tetrafluoroethylene copolymer (80/20 mol%) fluorinated methacrylate Copolymer: methacrylic acid 2,
2,2-trifluoroethyl / 2- (perfluorooctyl) ethyl methacrylate / methyl methacrylate copolymer (50/30/20% by weight)

According to the present invention, it is possible to provide a POF cable having a coating layer made of a polyamide resin having excellent adhesion between a bare POF wire and a coating material, and having excellent heat resistance and environmental resistance.
It is possible to provide a POF cable which has high resistance to vibration in a high-temperature environment and is particularly suitable for use in a vehicle-mounted application such as an automobile.

Further, the POF cable of the present invention is excellent in the connectivity with a POF having a numerical aperture of about 0.5, which is widely used conventionally, and a light receiving / emitting element designed for connection with the POF. This is suitable for use as a cable for relay wiring between an optical element unit disposed in an O / E conversion device and an external fiber.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a fixing jig for measuring a coating pull-out strength.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 6/44 301 G02B 6/44 301A (72) Inventor Kazumi Nakamura 1-6-1, Konan, Minato-ku, Tokyo No. Mitsubishi Rayon Co., Ltd. F-term (reference) 2H050 AA13 AB43X AB47Y BA16 BA34 BB03Q BB19Q BD03 4J011 AA05 FA02 FB05 NB04 4J015 AA02 AA04 AA06

Claims (13)

[Claims] 1. A plastic optical fiber element comprising a core material comprising a polymer comprising polymethyl methacrylate as a main component, and a sheath material comprising a polymer having a structural unit comprising α-fluoroacrylate ester on the outside thereof. In a plastic optical fiber cable provided with a coating layer made of a polyamide resin, when the plastic optical fiber wire is heat-treated at 105 ° C. for 24 hours, the heat shrinkage in the axial direction of the plastic optical fiber wire is 1.5% or less. When the plastic optical fiber cable provided with the coating layer of the polyamide resin was heat-treated at 105 ° C. for 100 hours, the pistoning was 1 to the entire length of the plastic optical fiber cable.
/ 10000 or less, the increase in transmission loss after heat treatment at 105 ° C for 1000 hours is 0.1 dB / m or less, and the pull-out strength between the plastic optical fiber and the coating layer is 15N or more. Plastic optical fiber cable. 2. The plastic optical fiber cable according to claim 1, wherein the core material is polymethyl methacrylate. 3. The polymer constituting the core material has a residual monomer content of 0.5% by weight or less, a residual mercaptan content of 10 ppm or less, and a dimer content of 0.3% or less.
The plastic optical fiber cable according to claim 1 or 2, wherein: 4. The α-fluoroacrylic acid ester, which is a constituent unit of the polymer constituting the sheath material, is selected from the group consisting of methyl α-fluoroacrylate, 2,2,2-trifluoroethyl α-fluoroacrylate, and α-fluoro Acrylic acid 2,2
The plastic optical fiber cable according to any one of claims 1 to 3, wherein the cable is at least one selected from 3,3,3-pentafluoropropyl. 5. The plastic optical fiber cable according to claim 4, wherein the sheath material has a glass transition temperature of 120 ° C. or higher. 6. The plastic optical fiber cable according to claim 1, wherein a layer made of vinylidene fluoride / tetrafluoroethylene copolymer is provided as an outermost layer of the plastic optical fiber. . 7. The plastic optical fiber cable according to claim 1, wherein the coating layer is nylon 12. 8. The plastic optical fiber cable according to claim 1, wherein the coating layer contains an organic acid or an organic acid anhydride. 9. The polymer constituting the core material is 2,2′-azobisisobutylonitrile, dimethyl 2,2′-azobisisobutyrate, or 2,2′-azobis (2,4,4-trimethylpentane). At least one as a thermal polymerization initiator,
Using normal butyl mercaptan as a chain transfer agent, 12
The plastic optical fiber cable according to any one of claims 1 to 8, wherein the plastic optical fiber cable is obtained by performing devolatilization extrusion after performing continuous bulk polymerization at a temperature of 5 ° C to 135 ° C. 10. A heat treatment is performed at a temperature lower than a lower one of a glass transition temperature of a core material of a plastic optical fiber and a glass transition temperature of a sheath material, and then a coating resin is coated to form a coating layer. The plastic optical fiber cable according to any one of claims 1 to 9, wherein: 11. A plastic optical fiber cable with a plug, wherein a plug is connected to one end or both ends of the plastic optical fiber cable according to any one of claims 1 to 10. 12. An optical transmission component wherein the coating layer of the plastic optical fiber cable or the plugged plastic optical fiber cable according to claim 1 is melted by heat and bonded to another component. . 13. A plastic optical fiber cable characterized in that the coating layer of the plastic optical fiber cable or the plugged plastic optical fiber cable according to any one of claims 1 to 11 is melted by heat and bonded to other parts. How to fix.