JP2010271710A - Plastic optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic optical fiber cable which has chemical resistance to chemicals such as alcohols, oil and fats, wax, lubricant, petroleum, and is reliable. <P>SOLUTION: The plastic optical fiber cable (10) includes an optical fiber and a coating layer (16) formed to coat the outer periphery of the optical fiber, wherein the thickness of the coating layer (16) is 50 to 700 μm, the melting point of the coating layer (16) is 150 to 250°C, and the coating layer includes ethylene-tetrafluoroethylene based copolymer having reactive functional group terminal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plastic optical fiber cable.

  A plastic optical fiber has a structure in which a core made of a transparent resin is surrounded by a sheath layer made of a resin having a refractive index lower than that of the transparent resin, and light is reflected at the boundary between the core and the sheath layer so that the inside of the core is reflected. This is a medium for transmitting optical signals. In general, a plastic optical fiber is used as a plastic optical fiber cable in which a coating resin layer is provided on the outside of a plastic optical fiber consisting of a core and a sheath layer in order to prevent physical or chemical damage.

  For example, as a plastic optical fiber excellent in heat resistance, a transparent resin constituting the core is a polymethyl methacrylate (hereinafter also referred to as “PMMA”) resin, and a sheath resin constituting the sheath layer is a polyvinylidene fluoride resin. A plastic optical fiber cable in which a fluorine-containing polyolefin resin is coated on a plastic optical fiber strand is proposed (see Patent Document 1).

  In addition, on a plastic optical fiber having a core resin as a PMMA resin and a sheath resin as a copolymer having a specific composition of vinylidene fluoride, tetrofluoroethylene, and hexafluoropropene, a polymer having a melting point of 120 ° C. or higher is used. A plastic optical fiber provided with a protective layer made of vinylidene fluoride resin, nylon 12 or nylon 11, and a cable with a jacket made of polyethylene, polyvinyl chloride, polyurethane, nylon, polypropylene, etc. on the outside are proposed. (See Patent Document 2).

  In addition, an attempt has been made to use a plastic optical fiber for a pedestrian detection sensor that detects a collision between a vehicle and a pedestrian (see Patent Document 3).

  As a plastic optical fiber using a fluorine-containing polyolefin resin as a coating layer, a plastic in which a fluorine-containing polyolefin resin having a melting point of 250 to 320 ° C. such as a copolymer of ethylene and tetrafluoroethylene is coated to a thickness of 2 to 50 μm. An optical fiber is known (see Patent Document 4).

  On the other hand, in the technical field of fuel-based resin hoses, laminated laminates of aliphatic polyamide resins and metal laminate films made by laminating a layer of a modified fluororesin or a modified tetrafluoroethylene copolymer on one or both sides of a metal foil Proposals for use have been made (see Patent Documents 5 and 6).

Japanese Patent No. 2951677 JP-A-11-160552 Japanese Patent No. 4082692 JP 2004-361610 A JP 2005-262673 A JP 2006-9957 A

  However, the polyvinylidene fluoride resin described in Patent Documents 1 and 2 may have insufficient chemical resistance depending on the environment in which it is used. In addition, since members that are brought in separately during long-term use may contain chemical substances that are harmful to optical fibers, it is desirable to have chemical resistance against chemical substances when expanding the use of optical fibers.

  In addition, when an optical fiber cable is used as in-vehicle wiring, FA equipment wiring, or household equipment wiring, members containing various chemical substances can be disposed around the optical fiber cable. Since the optical fiber cable can come into contact with these, if the wiring is performed carelessly, the optical fiber cable is deteriorated by the chemical substance, and there is a problem that the transmission loss becomes large or the wire breaks.

  Chemical substances that can affect the optical fiber cable include chemical substances such as alcohols, oils and fats, waxes, lubricants, and petroleums. In the above-mentioned application, it is necessary to evaluate compatibility with all chemical substances that may come into contact with the optical fiber cable before using the optical fiber cable. It has become.

  For example, in the technical field described in Patent Document 3, alcohol resistance is required because it may be splashed by a window shear liquid containing alcohol as a component.

  The optical fiber described in Patent Document 4 needs to be manufactured by a method of melt-coating a high melting point fluorine-containing polyolefin resin in contact with an optical fiber, so that only a coating thickness of about 2 to 50 μm can be obtained. Absent. Therefore, in order to sufficiently protect the optical fiber so as not to be damaged by a physical external force, there is a problem that another coating resin layer must be provided on the outer side.

  Therefore, the present invention has been made in view of the above circumstances, and is a highly reliable plastic that has chemical resistance to chemicals such as alcohols, fats and oils, waxes, lubricants, petroleums, and the like, and has low transmission loss and high reliability. An object is to provide an optical fiber cable.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have determined that the thickness of the coating layer is 50 to 700 μm, the melting point is 150 to 250 ° C., and ethylene-tetrafluoroethylene having a reactive functional group end. The present inventors have found that a plastic optical fiber cable having excellent chemical resistance and low transmission loss and high reliability can be obtained by using a coating layer containing a copolymer, and the present invention has been completed.

That is, the present invention is as follows.
[1]
An optical fiber cable having an optical fiber and a coating layer formed on the outer periphery of the optical fiber,
The coating layer has a thickness of 50 to 700 μm,
The covering layer has a melting point of 150 to 250 ° C. and includes an ethylene-tetrafluoroethylene copolymer having a reactive functional group terminal, and is a plastic optical fiber cable.
[2]
The plastic optical fiber cable according to [1], wherein the ethylene-tetrafluoroethylene copolymer having a reactive functional group terminal is a carbonate-modified ethylene-tetrafluoroethylene copolymer.
[3]
[1] or [1], wherein the optical fiber is composed of a core formed of a transparent resin and at least one sheath layer coated on the outer periphery of the core with a fluororesin having a refractive index lower than that of the transparent resin. 2] Plastic optical fiber cable.
[4]
[3] The plastic optical fiber cable according to [3], wherein the optical fiber further has a protective layer coated on the outer periphery of the sheath layer.
[5]
The plastic optical fiber cable according to any one of [1] to [4], wherein the optical fiber is a multi-core optical fiber.

  The plastic optical fiber cable of the present invention is excellent in chemical resistance of chemicals such as alcohols, fats, waxes, lubricants, petroleums, etc., and has low transmission loss and high reliability.

It is sectional drawing of the one aspect | mode of the single core optical fiber cable of this embodiment. It is sectional drawing of another aspect of the single core optical fiber cable of this embodiment. It is sectional drawing of the one aspect | mode of the multi-core optical fiber cable of this embodiment. It is sectional drawing of another aspect of the multi-core optical fiber cable of this embodiment. It is sectional drawing of another aspect of the multi-core optical fiber cable of this embodiment.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with appropriate modifications within the scope of the gist thereof.

  The plastic optical fiber cable of this embodiment is a plastic optical fiber cable having an optical fiber and a coating layer formed on the outer periphery of the optical fiber, and the thickness of the coating layer is 50 The coating layer has an melting point of 150 to 250 ° C. and contains an ethylene-tetrafluoroethylene copolymer having a reactive functional group terminal.

  In addition, the “coating layer formed on the outer periphery of the optical fiber” does not necessarily require that the outer peripheral surface of the optical fiber is in contact with the outer surface of the optical fiber, and between the coating layer and the optical fiber. Another layer may intervene.

  FIG. 1 is a cross-sectional view of one aspect of the single-core optical fiber cable of the present embodiment. A plastic optical fiber cable 10 shown in FIG. 1 is a single-core optical fiber cable having one core 12. The plastic optical fiber cable 10 has a core 12 at the center, and includes a sheath layer 14 formed on the outer periphery of the core 12 and a cover layer 16 formed on the outer periphery of the sheath layer 14. In this case, the core 12 and the sheath layer 14 are referred to as an optical fiber. An outer coating layer (not shown) may be further provided on the outer periphery of the coating layer 16. As a result, the optical fiber can be more reliably protected from the effects of long-term outdoor use and chemicals that come into contact therewith. The optical fiber cable according to the present embodiment is highly resistant to chemicals such as alcohols, oils and fats, waxes, lubricants, petroleums, plasticizers, and the like, and has a low transmission loss, and thus has high reliability.

  FIG. 2 is a cross-sectional view of another aspect of the single-core optical fiber cable of the present embodiment. As shown in FIG. 2, the plastic optical fiber cable of the present embodiment preferably includes a protective layer between the sheath layer and the covering layer. The plastic optical fiber cable 20 has a core 22 in the center, a sheath layer 24 coated on the outer periphery of the core 22, a protective layer 26 coated on the outer periphery of the sheath layer 24, and an outer periphery of the protective layer 26. And a coating layer 28 formed as a coating. By further including a protective layer coated on the outer periphery of the sheath layer, the optical fiber can be more reliably protected from long-term use in the field, the influence of chemicals that come into contact, and the like.

  FIG. 3 is a cross-sectional view of one aspect of the multi-core optical fiber cable of the present embodiment. As shown in FIG. 3, the plastic optical fiber cable of the present embodiment may be a multi-core optical fiber cable having a plurality of cores. The plastic optical fiber cable 30 is a seven-core type optical fiber cable. The plastic optical fiber cable 30 is multi-core by covering seven cores 32 with a sheath layer 34. The outer periphery of the sheath layer 34 is covered with a coating layer 36. An outer coating layer (not shown) may be further provided on the outer periphery of the coating layer 36. As a result, the optical fiber can be more reliably protected from long-term outdoor use and the influence of chemicals that come into contact therewith.

  FIG. 4 is a cross-sectional view of another aspect of the multi-core optical fiber cable of the present embodiment. As shown in FIG. 4, in the plastic optical fiber cable of this embodiment, each core may be individually covered with a sheath layer. The plastic optical fiber cable 40 has a core 42 covered with a first sheath layer 44, and is coated with a second sheath layer 46 to be multi-core. A coating layer 48 is formed on the outer periphery of the second sheath layer 46.

  FIG. 5 is a cross-sectional view of still another aspect of the multi-core optical fiber cable of the present embodiment. As shown in FIG. 5, it may be a multi-core optical fiber cable having a protective layer. Each of the plastic optical fiber cables 50 has a core 52 covered with a sheath layer 54, and the seven cores 52 covered with the sheath layer 54 are covered with a protective layer 56 to be multi-core. A coating layer 58 is formed on the outer periphery of the protective layer 56.

<Core>
The resin constituting the core (hereinafter also referred to as “core resin”) is preferably a transparent resin. As the core resin, those known as the core resin of plastic optical fibers can be used, and examples thereof include polymethyl methacrylate resin and polycarbonate resin. Among these, from the viewpoint of transparency, a polymethyl methacrylate resin is preferable.

  The polymethyl methacrylate resin refers to a homopolymer of methyl methacrylate or a copolymer containing 50% by mass or more of a methyl methacrylate component. The polymethyl methacrylate resin may be a copolymer containing methyl methacrylate and a component copolymerizable with methyl methacrylate. The component copolymerizable with methyl methacrylate is not particularly limited, and acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, and methacrylic acid esters such as ethyl methacrylate, propyl methacrylate, and cyclohexyl methacrylate. And maleimides such as isopropylmaleimide, acrylic acid, methacrylic acid, styrene and the like, and two or more of these may be selected.

  The molecular weight of the polymethyl methacrylate resin is preferably from 80,000 to 200,000, and more preferably from 100,000 to 120,000, as the weight average molecular weight, from the viewpoint of melt flow (ease of molding).

  The number of cores in the cross section of the optical fiber cable of the present embodiment is preferably one for a single core or at least seven for a multi-core, which allows for a circular arrangement. The maximum number of cores in the cross section in the case of a multi-core is preferably 10,000 or less, more preferably 19 to 1000, from the viewpoint of ease of manufacture. In the case of a multi-core, the core diameter is preferably 5 μm to 500 μm, more preferably 60 μm to 200 μm. If the core diameter is 5 μm or more, the amount of light passing therethrough can be further increased. Moreover, if the diameter of the core is 500 μm or less, the decrease in the amount of transmitted light due to bending can be further reduced.

<Sheath layer>
The sheath layer is formed on the outer periphery of the core. By providing the sheath layer, an optical signal is propagated in the optical fiber bent by reflection at the interface between the sheath layer and the core. A plurality of sheath layers may be formed. In that case, if the refractive index of the second sheath layer located outside the first sheath layer located inside is lowered, the first sheath layer is penetrated. It is preferable because a part of light can be collected by interface reflection between the first sheath layer and the second sheath layer.

  The resin constituting the sheath layer (hereinafter also referred to as “sheath resin”) is not particularly limited as long as the resin has a refractive index smaller than that of the resin constituting the core, and a known resin can be used. As a preferable aspect of the plastic optical fiber cable of the present embodiment, an optical fiber is coated on the outer periphery of the core with the core made of the above-described transparent resin and a fluororesin having a refractive index lower than that of the transparent resin. In addition, there may be mentioned at least one sheath layer. More preferably, the refractive index of the resin constituting the core is preferably 0.01 to 0.15 higher than the refractive index of the resin constituting the sheath layer. The smaller the difference in refractive index between the resin constituting the core and the resin constituting the sheath layer, the more the signal can be propagated up to a higher frequency, but the cable tends to be vulnerable to bending. On the other hand, the larger the difference in refractive index, the stronger the cable can be bent, but there is a tendency that high-frequency light does not pass easily. From this viewpoint, it is preferable that the difference in refractive index between the resin constituting the core and the resin constituting the sheath layer be within the above numerical range.

  Although it does not specifically limit as resin which comprises a sheath layer, Specifically, a fluororesin etc. are mentioned. Among them, a fluororesin having a high transmittance with respect to light to be used is preferable. Transmission loss can be further suppressed by using the fluororesin. Examples of the fluororesin include a fluorinated methacrylate polymer and a polyvinylidene fluoride resin.

  The fluorinated methacrylate polymer is not particularly limited, but contains fluorine such as fluoroalkyl methacrylate, fluoroalkyl acrylate, and α-fluoro-fluoroalkyl acrylate from the viewpoint of high transmittance and excellent heat resistance and moldability. Acrylate monomers or methacrylate monomers are preferred. Further, it may be a copolymer containing a fluorine-containing (meth) acrylate monomer and other components copolymerizable therewith, and a copolymer of a copolymerizable hydrocarbon monomer such as methyl methacrylate. Coalescence is preferred. It is preferable to use a copolymer of a fluorine-containing (meth) acrylate monomer and a hydrocarbon monomer copolymerizable therewith, because the refractive index can be controlled.

  On the other hand, the polyvinylidene fluoride resin is not particularly limited, but from the viewpoint of excellent heat resistance and moldability, vinylidene fluoride homopolymer; vinylidene fluoride, tetrafluoroethylene, hexafluoropropene, trifluoro A copolymer of at least one monomer selected from the group consisting of ethylene, hexafluoroacetone, perfluoroalkyl vinyl ether, chlorotrifluoroethylene, ethylene, and propylene; a polymer containing these vinylidene fluoride components and PMMA An alloy with a resin is preferable.

<Protective layer>
The protective layer is formed by coating the outer periphery of the sheath layer. The protective layer can impart functions such as mechanical properties, heat resistance, and light shielding properties to the optical fiber cable as necessary, and is a layer made of a resin in contact with the outside of the sheath layer. In this embodiment, when the refractive index is higher than that of the inner sheath layer, or is opaque or colored (that is, not transparent enough to reflect the target light), it is not the outer sheath layer. It shall be a protective layer. The material for the protective layer is not particularly limited, and, for example, polyvinylidene fluoride resin can be used. As the refractive index, a value measured at 20 ° C. with sodium D line is used.

  Here, in the case of a multi-core optical fiber cable, the ratio of the cross-sectional areas of the core, the sheath layer, and the protective layer in the cross section of the optical fiber is preferably 60 to 90%. 75 -90% is more preferable. The amount of 60% or more is preferable because a sufficient amount of light can be obtained. A content of 90% or less is preferable because a phenomenon in which the core deforms from a circular shape is less likely to occur, and a reduction in transmission loss can be suppressed.

  The cross-sectional area ratio of the sheath layer is preferably 2 to 20%, and more preferably 2 to 10%. By setting the lower limit of the cross-sectional area ratio of the sheath layer to the above numerical value, the thickness of the sheath layer that functions reliably as an optical fiber can be obtained. By setting the upper limit value of the cross-sectional area ratio of the sheath layer to the above numerical value, good area efficiency can be obtained.

  The cross-sectional area ratio of the protective layer is preferably 8 to 20%, more preferably 10 to 20%. By setting the upper limit value of the cross-sectional area ratio of the protective layer to the above value, the mechanical strength can be improved. By setting the upper limit value of the cross-sectional area ratio of the protective layer to the above numerical value, it is possible to achieve good area efficiency.

  The sheath layer is preferably arranged in a ring shape around the core, and the protective layer is preferably arranged so as to surround the sheath layer, particularly from the viewpoint of mechanical reinforcement, except for the core in the cross section of the optical fiber strand It is more preferable that most of the area is turned to the protective layer. In particular, the protective layer can exhibit a function of protecting the optical fiber cable from an external force such as a lateral pressure, and can also exhibit an effect of mitigating an external impact.

  In the present embodiment, in the case of a multi-core plastic optical fiber, the diameter of the strand is preferably 0.2 mm to 3.0 mm, more preferably 0.5 mm to 2.0 mm. Moreover, the thickness of a sheath layer becomes like this. Preferably they are 1 micrometer-30 micrometers, More preferably, they are 1 micrometer-20 micrometers. Furthermore, the thickness of the protective layer is preferably 1 μm to 50 μm, more preferably 1 μm to 30 μm. By setting it in the above numerical range, a multicore plastic optical fiber having a more stable transmission loss value can be obtained.

  In the case of a single-core optical fiber cable, the diameter of the strand is preferably 0.2 mm to 3.0 mm, the thickness of the sheath layer is preferably 2 μm to 50 μm, and the thickness of the protective layer is preferably 2 μm to 300 μm. It is. By setting it within the above numerical range, a single-core plastic optical fiber having a more stable transmission loss value can be obtained.

<Coating layer>
In the present embodiment, the coating layer is formed on the outer periphery of the optical fiber. The coating layer contains an ethylene-tetrafluoroethylene copolymer (hereinafter also referred to as “modified fluororesin”) having a melting point of 150 to 250 ° C. and having a reactive functional group terminal. The present inventor uses such a modified fluororesin for the coating layer, so that not only chemical resistance but also excellent heat resistance, water resistance, mechanical strength, and surface smoothness, It was found that surface tackiness can be suppressed. Here, “having a reactive functional group end” means having a reactive functional group at the end of the main chain and / or side chain.

  The modified fluororesin used as the coating layer may contain an ethylenic monomer in which all or some of the hydrogen atoms are substituted with fluorine atoms (halogen atoms other than fluorine such as chlorine may be included. Or a monomer copolymerizable with the fluorine-containing monomer, and a reactive functional group such as a carbonate group (carbonyldioxy) in the main chain or side chain. Group), an ester group, a haloformyl group, a carboxyl group and the like are introduced and modified. By introducing the reactive functional group described above, it is possible to improve the adhesion with an adjacent layer, particularly a protective layer or an outer coating layer. Among them, those having a carbonate group are preferable. The modified fluororesin introduced with a reactive functional group having a carbonate group can be easily introduced by using peroxycarbonate as a polymerization initiator at the time of polymerization of the modified fluororesin, has excellent adhesiveness with a wide range of resins, Among them, there are advantages such as particularly excellent adhesion to polyamide resins such as nylon 12. As a result, excellent chemical resistance and heat resistance can be imparted to the plastic optical fiber.

  Although content of the modified | denatured fluororesin in a coating layer is not specifically limited, 70 mass% or more is preferable, 85 mass% or more is more preferable, 90 mass% or more is further more preferable, 95 mass% or more is still more preferable. By setting it as the said content, the effect of this embodiment becomes still more remarkable.

  In addition, the above-described sheath layer, protective layer, coating layer, and the like may contain other additive components other than the modified fluororesin as long as the effects of the present embodiment are not impaired. Depending on the purpose of use, additives such as antioxidants, ultraviolet absorbers, light stabilizers, metal deactivators, lubricants, flame retardant (auxiliary) agents, fillers and the like can be used.

  The introduction of the reactive functional group is not particularly limited, and can be performed by, for example, a known method. However, it is preferably introduced into the copolymer as a polymerization initiator, and with respect to 100 parts by mass of the obtained copolymer. The polymerization initiator is preferably 0.05 to 20 parts by mass.

  The modified fluororesin has an ethylene-tetrafluoroethylene copolymer as a main skeleton. The molar ratio of ethylene / tetrafluoroethylene in the ethylene-tetrafluoroethylene copolymer is not particularly limited, but is preferably 70/30 to 30/70 from the viewpoint of the balance between moldability and chemical resistance. . Furthermore, together with tetrafluoroethylene and ethylene, other monomers copolymerizable therewith (for example, hexafluoropropylene, hexafluoroisobutene, propylene, 1-butene, 2-butene, vinyl chloride, vinylidene chloride, fluoride It may be a copolymer of olefins such as vinylidene, chlorotrifluoroethylene, vinyl fluoride, hexafluoroisobutene, perfluoro (alkyl vinyl ether), etc. In this case, ethylene / tetrafluoroethylene / copolymerizable others The molar ratio of the monomer is not particularly limited, but is preferably (10-80) / (20-80) / (0-40) from the viewpoint of the balance between moldability and chemical resistance.

  More preferable modified fluororesin is a polymer chain obtained from a monomer component composed of tetrafluoroethylene 62 to 80 mol%, ethylene 20 to 38 mol%, and monomers 0 to 10 mol% copolymerizable therewith. A carbonyldioxy group-containing copolymer having tetrafluoroethylene 20-80 mol%, ethylene 10-80 mol%, hexafluoropropylene 0-30 mol%, and monomers 0-10 mol copolymerizable therewith A carbonyldioxy group-containing copolymer having a polymer chain obtained from a monomer component consisting of%. The modified fluororesin is preferable because it is excellent in chemical resistance and heat resistance.

  The melting point of the modified fluororesin is in the range of 150 ° C to 250 ° C. When the melting point is within such a temperature range, it is preferable because molding can be performed at a molding temperature of 300 ° C. or lower that allows thermal decomposition of the polymethyl methacrylate resin. The melting point can be measured by differential scanning calorimetry. For example, the temperature can be measured by using a differential scanning calorimeter (EXSTAR DSC6200) manufactured by Seiko Instruments Inc. and heating the sample at a temperature rising rate of 20 ° C./min.

  As such a modified fluororesin, commercially available products include NEOFRON EFEP RP5000 and RP4020 manufactured by Daikin Industries, Ltd., and Fullon LM-ETFE AH2000 manufactured by Asahi Glass. Among these, NEOFRON EFEP RP5000 and RP4020 are carbonate-modified ethylene-tetrafluoroethylene copolymers containing a carbonyldioxy group as a reactive functional group.

  In this embodiment, the thickness of the coating layer is 50 μm to 700 μm. If the thickness is less than 50 μm, the mechanical strength cannot be secured sufficiently by coating the outer periphery of the optical fiber with the modified fluororesin. If it exceeds 700 μm, the cable becomes too rigid, which is not preferable. From this viewpoint, a more preferable thickness is 100 μm to 300 μm.

<Outer coating layer>
Although the optical fiber cable of this embodiment can use the coating layer as the outermost surface layer, the outer periphery thereof is made of a thermoplastic resin such as nylon 12, soft nylon, polyethylene, polyvinyl chloride, polypropylene, or fluororesin. An outer coating layer (also referred to as “outer jacket”) may be applied to provide a more reinforced optical fiber cable.

  As described above, the optical fiber cable of this embodiment may be either a single-core or multi-core type. In the case of a multi-core, the optical fiber cable may be of a type having 7 or more cores. .

<Manufacturing method>
Production of the plastic optical fiber cable of the present embodiment is not particularly limited, and can be performed by a known method. For example, a method of coating and forming the modified fluororesin heat-melted by a crosshead die on the outside of a plastic optical fiber produced by a known composite spinning method can be preferably used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.

[Measuring method]
(1) Refractive index measurement The value measured at 20 ° C. using sodium D line was adopted.
(2) Melt flow index measurement It measured based on ASTM D1238.
(3) Melting point measurement The melting point was measured by differential scanning calorimetry. The measurement was performed by heating the sample at a temperature rising rate of 20 ° C./min using a differential scanning calorimeter (EXSTAR DSC6200) manufactured by Seiko Instruments Inc.
(4) Shore D hardness measurement It measured based on ASTM D2240.

<Example 1>
The core resin is a polymethyl methacrylate resin having a refractive index of 1.492 measured at 20 ° C. with sodium D line, a weight average molecular weight of 100,000, a melt flow index of 230 ° C., a load of 3.8 kg, Under the conditions of a diameter of 2 mm and a length of 8 mm, the one having 2.5 g / 10 minutes was used.

  As a sheath resin, a copolymer comprising 57% by mole of vinylidene fluoride, 32% by mole of tetrofluoroethylene, and 11% by mole of hexafluoropropene, having a melt flow index of 8 g / 10 minutes and a refractive index of 1.36, A resin having a melting point of 120 ° C. was used.

  The core resin and sheath resin were introduced into a two-layer composite die, and the die temperature was spun at 235 ° C. The strand discharged from the die was stretched twice and heat-treated to obtain a single-core plastic optical fiber having a core diameter of 980 μm and a sheath thickness of 10 μm and a diameter of 1000 μm as shown in FIG. The transmission loss measured by the 52 m-2 m cutback method using a light source having a wavelength of 650 nm and an aperture angle of 0.16 radians was 135 dB / km.

  Next, a modified fluororesin (manufactured by Daikin Industries, NEOFRON EFEP RP5000: melting point 200 ° C.) melted at 250 ° C. is introduced into a crosshead die for covering the electric wire to a thickness of 200 μm. An optical fiber cable having a diameter of 1400 μm was obtained. The transmission loss measured by the 52 m-2 m cutback method using a light source with a wavelength of 650 nm and an aperture angle of 0.16 radians was 143 dB / km.

  3 m of the plastic optical fiber cable thus manufactured was taken, and 1.5 m of the cable was immersed in 99.8% ethanol at room temperature, and the change with time was observed. First, regarding the transmission performance, the optical power was measured with a tester with an LED light of 650 nm (manufactured by Hakutronics, Optical Power Meter PHOTO205), and the value before immersion was -10.9 dBm, while 240 The value after time was also −10.9 dBm, which was stable, the diameter of the immersion part was 1415 μm, and the swelling was small.

  Further, 3 m of the plastic optical fiber cable of Example 1 was taken, and 1 m of that was immersed in N, N-dimethylformaldehyde (DMF) at room temperature, and the change with time was observed. First, the transmission performance was measured with an optical power meter with an LED light of 650 nm (manufactured by Haktronics, optical power meter PHOTOM 205). While the value before immersion was -10.8 dBm, the value after 240 hours was also -10.8 dBm and was stable.

  Further, 3 m of the plastic optical fiber cable of Example 1 was taken, and 1 m of the cable was immersed in a brake fluid (Toyota brake fluid 2500H) at room temperature, and the change with time was observed. First, the transmission performance was measured with an optical power meter with an LED light of 650 nm (manufactured by Hakutronics, Optical Power Meter PHOTO205), and values before immersion were -10.5 dBm and -10.6 dBm. On the other hand, the values after 3000 hours were also −10.6 dBm and −10.6 dBm, and were stable.

<Example 2>
The strand of Example 1 was introduced into a crosshead die for covering electric wires, and a modified fluororesin (manufactured by Daikin Industries, NEOFRON EFEP RP4020: melting point 166 ° C.) melted at 235 ° C. was coated to a thickness of 600 μm. A single-core optical fiber cable having a structure shown in FIG. 1 and having a diameter of 2200 μm was obtained. The transmission loss measured by the 52 m-2 m cutback method using a light source with a wavelength of 650 nm and an aperture angle of 0.16 radians was 140 dB / km.

  3 m of the plastic optical fiber cable thus manufactured was taken, and 1.5 m of the cable was immersed in 99.8% ethanol at room temperature, and the change with time was observed. First, regarding the transmission performance, the optical power was measured with a tester with an LED light of 650 nm (manufactured by Hakutronics, Optical Power Meter PHOTO205), and the value before immersion was −10.3 dBm, whereas 240 The value after time was also −10.4 dBm, which was stable, the diameter of the immersion part was 2224 μm, and the swelling was small.

  Further, 3 m of the plastic optical fiber cable of Example 2 was taken, and 1 m of the cable was immersed in DMF (N, N-dimethylformaldehyde) at room temperature, and the change with time was observed. First, the transmission performance was measured with an optical power meter with an LED light of 650 nm (manufactured by Haktronics, optical power meter PHOTOM 205). While the value before immersion was -10.3 dBm, the value after 240 hours was also stable at -10.3 dBm.

  Further, 3 m of the plastic optical fiber cable of Example 2 was taken, and 1 m of the cable was immersed in a brake fluid (Toyota brake fluid 2500H) at room temperature, and the change with time was observed. First, regarding the transmission performance, two optical power meters with an LED light of 650 nm (manufactured by Hakutronics, Optical Power Meter PHOTO205) were measured, and values before immersion were −10.2 dBm and −10.4 dBm. On the other hand, the values after 3000 hours were also −10.2 dBm and −10.4 dBm, which were stable.

<Example 3>
The core resin is a polymethyl methacrylate resin having a refractive index of 1.492 measured at 20 ° C. with sodium D line, a weight average molecular weight of 100,000, a melt flow index of 230 ° C., a load of 3.8 kg, Under the conditions of a diameter of 2 mm and a length of 8 mm, the one having 2.5 g / 10 minutes was used.

  As a sheath resin, a copolymer comprising 57% by mole of vinylidene fluoride, 32% by mole of tetrofluoroethylene, and 11% by mole of hexafluoropropene, having a melt flow index of 8 g / 10 minutes and a refractive index of 1.36, A resin having a melting point of 120 ° C. was used.

  As a resin for the coating layer, a single amount comprising 43 mol% tetrafluoroethylene, 41 mol% ethylene, 15.5 mol% hexafluoropropylene, 0.5 mol% perfluoro (1,1,5-trihydro-pentene) A carbonyldioxy group-containing copolymer having a carbonyldioxy group introduced at the ends of the main chain and side chain of the polymer chain obtained from the body component, having a refractive index of 1.358, a melt flow index of 230 ° C., a load A modified fluororesin having a value of 3.8 kg, an orifice diameter of 2 mm, a length of 8 mm, 11 g / 10 minutes, a melting point of 166 ° C., and a Shore D hardness value of 67 was used.

  The core resin and sheath resin were introduced into a two-layer composite die, and the die temperature was spun at 235 ° C. The strand discharged from the die was stretched twice and heat-treated to obtain a single-core plastic optical fiber having a core diameter of 980 μm and a sheath thickness of 10 μm and a diameter of 1000 μm as shown in FIG. The transmission loss measured by the 52 m-2 m cutback method using a light source having a wavelength of 650 nm and an aperture angle of 0.16 radians was 135 dB / km.

  The plastic optical fiber was introduced into a crosshead die for covering electric wires, and the modified fluororesin melted at 235 ° C. was coated to a thickness of 600 μm to obtain an optical fiber cable having a diameter of 2200 μm. The transmission loss measured by the 52 m-2 m cutback method using a light source with a wavelength of 650 nm and an aperture angle of 0.16 radians was 140 dB / km.

  3 m of the plastic optical fiber cable thus manufactured was taken, and 1.5 m of the cable was immersed in 99.8% ethanol at room temperature, and the change with time was observed. First, regarding the transmission performance, the optical power was measured with a tester with an LED light of 650 nm (manufactured by Hakutronics, Optical Power Meter PHOTO205), and the value before immersion was −10.3 dBm, whereas 240 The value after time was also stable at −10.4 dBm, the diameter of the immersion part was 2224 μm, and the swelling was small.

  Further, 3 m of the plastic optical fiber cable of Example 3 was taken, and 1 m of the cable was immersed in DMF (N, N-dimethylformaldehyde) at room temperature, and the change with time was observed. First, the transmission performance was measured with an optical power meter with an LED light of 650 nm (manufactured by Haktronics, optical power meter PHOTOM 205). While the value before immersion was -10.3 dBm, the value after 240 hours was also stable at -10.3 dBm.

  Further, 3 m of the plastic optical fiber cable of Example 3 was taken, and 1 m of the cable was immersed in a brake fluid (Toyota brake fluid 2500H) at room temperature, and the change with time was observed. First, regarding the transmission performance, two optical power meters with an LED light of 650 nm (manufactured by Hakutronics, Optical Power Meter PHOTO205) were measured, and values before immersion were −10.2 dBm and −10.4 dBm. On the other hand, the values after 3000 hours were also −10.2 dBm and −10.4 dBm, which were stable.

<Comparative Example 1>
The plastic optical fiber used in Example 1 was introduced into a crosshead die for covering electric wires, and at 12O 0 C, nylon 12 (melting point: 178 ° C) was coated to a thickness of 200 µm, and the diameter was 1400 µm. A single core cable was obtained. The transmission loss measured by the 52 m-2 m cutback method using a light source having a wavelength of 650 nm and an aperture angle of 0.16 radians was 138 dB / km.

  3 m of the plastic optical fiber cable thus manufactured was taken, and 1.5 m of the cable was immersed in 99.8% ethanol at room temperature. Regarding the transmission performance, the optical power was measured with an optical power meter (manufactured by Hacktronics, Optical Power Meter PHOTOM 205) with LED light of 650 nm, and the value before immersion was −10.9 dBm, whereas 120 After a time, it decreased to -14.4 dBm, and the diameter of the immersion part was swollen at 1440 μm.

  From the above, it was confirmed that the plastic optical fiber cable of this embodiment is excellent in chemical resistance and has little reduction in transmission loss.

  The plastic optical fiber cable of the present invention is resistant to alcohols, oils and fats, waxes, lubricants, chemicals such as petroleum, and has low transmission loss and high reliability. Even where there is a possibility of contact with chemicals such as an internal machine, it can be suitably used.

10, 20, 30, 40, 50 Plastic optical fiber cable 12, 22, 32, 42, 52 Core 14, 24, 34, 44, 46, 54 Sheath layer 26, 56 Protective layer 16, 28, 36, 48, 58 Coating layer

Claims (5)

An optical fiber cable having an optical fiber and a coating layer formed on the outer periphery of the optical fiber,
The coating layer has a thickness of 50 to 700 μm,
The covering layer has a melting point of 150 to 250 ° C., and includes an ethylene-tetrafluoroethylene copolymer having a reactive functional group terminal, and is a plastic optical fiber cable.   The plastic optical fiber cable according to claim 1, wherein the ethylene-tetrafluoroethylene copolymer having a reactive functional group terminal is a carbonate-modified ethylene-tetrafluoroethylene copolymer.   The said optical fiber strand consists of a core formed with a transparent resin, and at least one sheath layer coated on the outer periphery of the core with a fluororesin having a refractive index lower than that of the transparent resin. The plastic optical fiber cable described in 1.   The plastic optical fiber cable according to claim 3, wherein the optical fiber further has a protective layer coated on an outer periphery of the sheath layer.   The plastic optical fiber cable according to any one of claims 1 to 4, wherein the optical fiber strand is a multi-core optical fiber strand.

Images