JP2010286832A - Plastic optical fiber and cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable plastic optical fiber and cable, having a high numerical aperture and heat resistance, and chemical-resistant against alcohols, oils and fats, waxes, lubricants and petroleums. <P>SOLUTION: The plastic optical fiber 10 includes a core 12 formed of a transparent resin, and a sheath layer 14 formed in the periphery of the core 12 and comprising at least one layer of modified fluororesin, and the modified fluororesin is an ethylene-tetrafluoro ethylene copolymer having a melting point within a range of 150-200°C, 1.37-1.41 of refractive index measured at 20°C by a sodium D-ray, and 5-100 g/10 min. of molten flow index (230°C, 3.8 kg of load, 2 mm of orifice diameter, and 8 mm of length), and containing a reactive functional terminal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plastic optical fiber and a 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 lower refractive index than the transparent resin, and light is reflected at the boundary between the core and the sheath layer. A medium for transmitting an optical signal in the core. In general, a plastic optical fiber is used as a plastic optical fiber cable in which a coating 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, a plastic optical fiber having a high numerical aperture, heat resistance, and excellent chemical resistance, the core is made of polymethyl methacrylate resin, and the sheath layer is vinylidene fluoride, hexafluoropropene, and tetrafluoro A plastic optical fiber made of an ethylene copolymer has been proposed (see Patent Document 1).

  Also, a plastic optical fiber element comprising a core made of a polymethylmethacrylate resin and a sheath layer made of a copolymer of vinylidene fluoride, tetrafluoroethylene, and hexafluoropropene, and then subjected to drawing heat treatment. A plastic optical fiber cable has been proposed in which a coating layer made of nylon 12 is directly coated on the outside (see Patent Document 2).

JP 2001-174646 A JP 2000-266970 A

  When a plastic optical fiber is used, members containing various chemical substances can be arranged around the plastic optical fiber depending on the application. Since the plastic optical fiber can come into contact with these, if the wiring is performed carelessly, the chemical substance may cause the plastic optical fiber to be deteriorated, resulting in an increase in transmission loss or a failure that leads to disconnection.

  Known chemical substances that can affect plastic optical fibers include alcohols and PVC plasticizers, but other chemicals such as fats, waxes, lubricants, plasticizers, and petroleum Should be careful. Therefore, before using a plastic optical fiber, it is necessary to evaluate compatibility with all chemical substances that the plastic optical fiber may come into contact with.

  For example, in the use of a pedestrian detection sensor that detects a collision between a vehicle and a pedestrian, the plastic optical fiber is required to have alcohol resistance because it may be splashed by a window washer liquid mainly composed of alcohol. However, the plastic optical fiber strands and plastic optical fiber cables described in Patent Document 1 and Patent Document 2 are not sufficient for alcohol and oils and fats for the application.

  The present invention has been made in view of the above circumstances, has a high numerical aperture and heat resistance, and has high chemical resistance to chemicals such as alcohols, fats, waxes, lubricants, petroleums, and the like. An object of the present invention is to provide a plastic optical fiber and a cable.

  As a result of studying to solve the above problems, the present inventor, as a resin constituting the sheath layer of the plastic optical fiber strand, by using a fluororesin that has been modified within a range that does not impair the original properties of the fluororesin, The present inventors have found that a plastic optical fiber and cable having a high numerical aperture and heat resistance and excellent chemical resistance and high reliability can be obtained, and the present invention has been completed.

That is, the present invention is as follows.
[1]
A plastic optical fiber having a core formed of a transparent resin and a sheath layer made of at least one layer of a modified fluororesin formed around the core,
The modified fluororesin has a melting point in the range of 150 to 200 ° C., the refractive index measured at 20 ° C. with sodium D line is 1.37 to 1.41, and the melt flow index (230 ° C., load 3. A plastic optical fiber, which is an ethylene-tetrafluoroethylene copolymer resin having a reactive functional group terminal, having a diameter of 8 kg, an orifice diameter of 2 mm, and a length of 8 mm) of 5 to 100 g / 10 min.
[2]
The plastic optical fiber according to [1], wherein the transparent resin is a polymethyl methacrylate resin.
[3]
The plastic optical fiber strand according to [1] or [2], wherein the modified fluororesin is a carbonate-modified ethylene-tetrafluoroethylene-based copolymer.
[4]
[1] to [3] The plastic optical fiber strand according to any one of
A coating layer containing a thermoplastic resin formed on the outside of the plastic optical fiber;
A plastic optical fiber cable.
[5]
The sheath layer comprises at least two layers,
The outermost layer of the sheath layer includes 40 to 62 mol% of vinylidene fluoride component, more than 28 mol% of tetrafluoroethylene component and 40 mol% or less, and 8 to 22 mol% of hexafluoropropene component. Made of polymer,
The plastic optical fiber cable according to [4], wherein the coating layer in contact with the outside of the outermost layer of the sheath layer contains a polyamide resin.

  The plastic optical fiber and cable of the present invention have a high numerical aperture and heat resistance, and are also highly resistant to chemicals such as alcohols, oils and fats, waxes, lubricants, petroleums, etc., and have 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.

  FIG. 1 is a cross-sectional view of one aspect of the plastic optical fiber cable of the present embodiment. The plastic optical fiber cable 10 shown in FIG. 1 is a single-core plastic 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 coating 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 a plastic optical fiber. The sheath layer 2 may be composed of a plurality of layers whose refractive index decreases as the outer layer is formed. Further, an outer coating layer (not shown) may be further provided outside the coating layer 16. As a result, the plastic optical fiber can be more reliably protected from long-term outdoor use and the influence of 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 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. A coating layer 36 is formed on the outer periphery of the sheath layer 34. 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.

  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. Hereinafter, each layer will be described.

  The type of resin constituting the core (hereinafter also referred to as “core resin”) is not particularly limited, and may be a transparent resin. As the transparent resin, conventionally known resins can be used as the core resin of the plastic optical fiber, and examples thereof include polymethyl methacrylate (PMMA) resin and polycarbonate resin. Among them, polymethyl methacrylate resin is particularly preferable from the viewpoint of transparency.

  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. Examples of components copolymerizable with the methyl methacrylate component include acrylic acid esters such as methyl acrylate, ethyl acrylate and butyl acrylate, methacrylates such as ethyl methacrylate, propyl methacrylate and cyclohexyl methacrylate, and isopropyl maleimide. And the like, and acrylic acid, methacrylic acid, styrene, etc. are mentioned, and those obtained by appropriately selecting one or more from these and copolymerizing them are preferred.

  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 sheath layer is coated on the outside 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. In this embodiment, 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 critical angle is exceeded. It is preferable because at least a part of the light penetrating the first sheath layer can be collected by interface reflection between the first sheath layer and the second sheath layer.

  As the resin constituting the sheath layer (hereinafter also referred to as “sheath resin”), a known resin can be used as long as it has a lower refractive index than that of the core resin. What is necessary is just to contain the modified | denatured fluororesin which has the characteristics of these. That is, when the sheath layer is composed of a plurality of layers, at least one of the sheath layers has a melting point in the range of 150 to 200 ° C., and the refractive index measured at 20 ° C. with sodium D line is 1.37 to 1. .41, the melt flow index (230 ° C., load 3.8 kg, orifice diameter 2 mm, length 8 mm) is 5 to 100 g / 10 min, and has a reactive functional group terminal, an ethylene-tetrafluoroethylene copolymer. It contains a modified fluororesin that is a polymer resin.

  The modified fluororesin is an ethylenic monomer in which all or a part of hydrogen atoms are substituted with fluorine atoms (may contain halogen atoms other than fluorine such as chlorine. Hereinafter, it is also referred to as “fluorinated monomer”. ), Or a copolymer of a monomer copolymerizable with the fluorine-containing monomer, which has a reactive functional group (for example, carbonate group (carbonyldioxy group), ester on the main chain or side chain). Group, haloformyl group, carboxyl group, etc.) are introduced and modified. Here, “having a reactive functional group end” means having a reactive functional group at the end of the main chain and / or side chain.

  By introducing the reactive functional group, not only the chemical resistance and heat resistance are excellent, but also the adhesion to an adjacent layer, particularly a coating layer containing a thermoplastic resin, can be improved. Of the reactive functional groups, those having a carbonate group are particularly preferred from the viewpoints of chemical resistance and heat resistance and adhesiveness to the coating layer. 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 and the plastic optical fiber cable.

  The introduction of these reactive functional groups can be carried out by a known method, but it is preferably introduced into the copolymer as a polymerization initiator, and the polymerization initiator is added to 100 parts by mass of the obtained copolymer. It is preferable that it is 0.05-20 mass parts.

  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 Copolymerized olefins such as vinylidene, chlorotrifluoroethylene, vinyl fluoride, hexafluoroisobutene and perfluoro (alkyl vinyl ether) may also be used.

  In this case, the molar ratio of ethylene / tetrafluoroethylene / other copolymerizable monomers is not particularly limited, but (10-80) / (20-80) from the viewpoint of the balance between moldability and chemical resistance. ) / (0 to 40).

  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 particularly excellent in chemical resistance and heat resistance.

  The melting point of the modified fluororesin is preferably in the range of 150 ° C to 200 ° 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, it can be measured 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.

  In the present embodiment, the modified fluororesin is preferably an ethylene-tetrafluoroethylene copolymer resin having a reactive functional group terminal. The ethylene-tetrafluoroethylene copolymer resin may be a copolymer obtained by copolymerizing monomers such as propylene together with tetrafluoroethylene and ethylene. Among these, if the melting point is in the range of 150 ° C. to 200 ° C. and the melt flow index (230 ° C., load 3.8 kg, orifice diameter 2 mm, length 8 mm) is 5 to 100 g / 10 min, polymethyl methacrylate type It is preferable because the resin can be molded at a molding temperature of 300 ° C. or less that allows thermal decomposition of the resin. The resin usually has a Shore D hardness (ASTM D2240) value at 23 ° C. in the range of 60-80. Although the Shore D hardness is increased, the introduction of a reactive functional group into the sheath resin causes adhesion with the core, and even with a hard sheath resin, it is difficult to peel off from the core, and the problem of the core popping out of the sheath is It is not expected to occur.

  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.

  The sheath layer is preferably formed from a sheath resin containing 70% by mass or more of an ethylene-tetrafluoroethylene copolymer having a reactive functional group terminal, more preferably 85% by mass or more, and still more preferably 90% by mass. % Or more, particularly preferably 95% by mass or more.

  In the present embodiment, when the sheath layer is configured in multiple layers and the modified fluororesin is used as the inner sheath resin that configures the first sheath layer positioned on the inner side, the second sheath layer positioned on the outer side is configured. As the outer sheath resin, a vinylidene fluoride resin having a refractive index smaller than that of the modified fluororesin is preferable. On the other hand, when the modified fluororesin is used as the outer sheath resin, a fluorinated methacrylate resin having a refractive index larger than that of the modified fluororesin is preferred as the inner sheath resin.

  Although it does not specifically limit as vinylidene fluoride type-resin, From the viewpoint of being excellent in heat resistance and a moldability, the homopolymer of vinylidene fluoride; vinylidene fluoride and tetrafluoroethylene, hexafluoro propene, trifluoroethylene, hexa A copolymer of at least one monomer selected from the group consisting of fluoroacetone, perfluoroalkyl vinyl ether, chlorotrifluoroethylene, ethylene, and propylene; a polymer containing these vinylidene fluoride components and a PMMA resin; Are preferred.

  The fluorinated methacrylate-based resin is not particularly limited, but contains fluorine such as fluoroalkyl methacrylate, fluoroalkyl acrylate, 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. A copolymer of a fluorine-containing (meth) acrylate monomer and a hydrocarbon monomer copolymerizable therewith is preferable because the refractive index can be controlled.

  In the single-core plastic optical fiber, the diameter of the strand is preferably 200 μm to 3000 μm, and the thickness of the sheath layer is preferably 5 μm to 50 μm. If the thickness of the sheath layer is 5 μm or more, the mechanical strength and chemical resistance are improved by coating the modified fluororesin. Moreover, if the thickness of the sheath layer is within 50 μm, a sufficient cross-sectional area of the core that functions as an optical fiber can be secured.

  Next, a multi-core plastic optical fiber having a plurality of cores will be described. 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, so that a circular arrangement is possible. The maximum number of cores in the cross section in the case of multi-core is preferably within 10,000 because of ease of manufacture. More preferably, it is 19-1000. In the case of a multi-core, the core diameter is preferably 5 μm to 500 μm. More preferably, it is 60 micrometers-200 micrometers. If the core diameter is 5 μm or more, the amount of light passing therethrough can be increased. Moreover, if the diameter of the core is 500 μm or less, a decrease in the amount of transmitted light due to bending can be reduced.

  Here, in the case of a multi-core plastic optical fiber, the ratio of the cross-sectional areas of the core, the first sheath layer, and the second sheath layer in the cross section of the optical fiber will be described. % Is preferable, and 75 to 90% is more preferable. 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, so that a reduction in transmission loss can be suppressed.

  The cross-sectional area ratio of the first 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 first sheath layer to the above numerical value, the thickness of the sheath layer that functions reliably as an optical fiber can be obtained. Moreover, it can be set as favorable area efficiency by making the upper limit of the cross-sectional area ratio of a 1st sheath layer into the said numerical value.

  The cross-sectional area ratio of the second sheath 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 second sheath layer to the above numerical value, the mechanical strength can be improved. By setting the upper limit value of the cross-sectional area ratio of the second sheath layer to the above numerical value, it is possible to achieve good area efficiency.

  The first sheath layer is preferably arranged in a ring around the core, and the second sheath layer is preferably arranged so as to surround the first sheath layer, particularly for mechanical reinforcement. The majority of the area other than the core in the cross section of the optical fiber is preferably turned to the protective layer. In particular, the second sheath layer can exhibit a function of protecting the optical fiber cable from an external force such as a side pressure, and can also exhibit an effect of mitigating an external impact. Further, the first sheath layer and the second sheath layer may be made of the same resin and integrated.

  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. The thickness of the first sheath layer is preferably 1 μm to 30 μm, more preferably 1 μm to 20 μm. Furthermore, the thickness of the second sheath layer is preferably 1 μm to 50 μm, more preferably 1 μm to 30 μm. By setting the numerical value within the above range, a multicore plastic optical fiber having a stable transmission loss value can be obtained.

  The plastic optical fiber wire of this embodiment can be used as it is, but mechanical and chemical durability can be obtained by forming a plastic optical fiber cable with a coating layer formed on the outer periphery of the strand. Can be improved. Examples of the resin constituting the coating layer (hereinafter also referred to as “coating resin”) include polyethylene resin, polyvinyl chloride resin, polypropylene resin, polyester resin, polyurethane resin, polyamide resin, polyolefin elastomer resin, and the like. These thermoplastic resins can be used. As the thermoplastic resin, a polyamide-based resin is preferable, and among them, nylon 12 is more preferable. In coating the coating layer, a method of forming the coating layer on the plastic optical fiber using a crosshead die can be preferably used.

  In particular, the sheath layer is composed of at least two layers, and the outermost layer of the sheath layer is 40 to 62 mol% of vinylidene fluoride component, more than 28 mol% of tetrafluoroethylene component and 40 mol% or less of hexafluoropropene component. More preferably, the coating layer in contact with the outside of the outermost layer of the sheath layer contains a polyamide-based resin, comprising a copolymer (vinylidene fluoride-based resin) containing 8 to 22 mol%. In particular, when nylon 12 is directly coated on a plastic optical fiber, the outer sheath resin and nylon 12 are more strongly adhered to each other and can be handled as a unit, which is more preferable.

  The thickness of the coating layer is preferably 50 μm to 700 μm. A thickness of 50 μm or more is preferable because the mechanical strength is further improved. Moreover, if thickness is 700 micrometers or less, since a moderate softness | flexibility can be hold | maintained, it is preferable. A more preferable thickness is 100 μm to 300 μm.

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

  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.

  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 the outer side of a plastic optical fiber manufactured by a known composite spinning method with a resin thermally melted by a crosshead die can be preferably used.

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

(1) Refractive Index Measurement A value measured at 20 ° C. using a 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 melting point was measured by heating the sample at a heating rate of 20 ° C./min using a differential scanning calorimeter (EXSTAR DSC6200) manufactured by Seiko Instruments Inc.
(4) Shore D hardness Measured according to 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, an orifice Under the conditions of a diameter of 2 mm and a length of 8 mm, 1.5 g / 10 min was used. As a sheath resin, a modified fluororesin having a refractive index of 1.385, a melt flow index of 11 g / 10 min, a melting point of 166 ° C., and a Shore D hardness (ASTM D2240) value of 67 (manufactured by Daikin Industries, NEOFRON EFEP RP4020) ) Was used.

  The core resin and sheath resin were introduced into a two-layer composite die, and the die temperature was spun at 240 ° C. The strand discharged from the die was stretched twice and heat-treated to obtain a plastic optical fiber having a core diameter of 980 μm and a sheath layer thickness of 10 μm and a diameter of 1000 μm. The transmission loss measured by the 52 m-2 m cut-back method at a wavelength of 650 nm and an incident numerical aperture (incidence NA) of 0.15 was 135 dB / km.

  The plastic optical fiber thus produced was wound 20 times around a stainless steel rod having a radius of 10 mm, ethanol having a content of 99.5% was dropped, and the occurrence probability of environmental stress cracks was examined. It occurred in 1 out of 10 pieces.

  Further, 3 m of a plastic optical fiber was taken, and 1 m 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 in the mixed solution were -10. 6 dBm and -10. The value after 3000 hours was not changed between -10.6 dBm and -10.7 dBm with respect to 7 dBm.

  Next, this plastic optical fiber was introduced into a crosshead die for covering electric wires, and at 210 ° C., nylon 12 was coated to a thickness of 250 μm to obtain a cable having a diameter of 1500 μm. The plastic optical fiber cable was removed by leaving 30 mm of the coating layer, and the pulling strength of the primary coating layer was measured through a hole having a diameter of 1.1 mm. The pull-out strength was 21N.

<Example 2>
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, an orifice Under the conditions of a diameter of 2 mm and a length of 8 mm, 1.5 g / 10 min was used. As the sheath resin, a single amount comprising 43 mol% tetrafluoroethylene, 41 mol% ethylene, 15.5 mol% hexafluoropropylene, 0.5 mol% perfluoro (1,1,5-trihydro-1-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 1.385 and a melt flow index of 11 g / 10 min A modified fluororesin having a melting point of 166 ° C. and a Shore D hardness (ASTM D2240) 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 240 ° C. The strand discharged from the die was stretched twice and heat-treated to obtain a plastic optical fiber having a core diameter of 980 μm and a sheath layer thickness of 10 μm and a diameter of 1000 μm. The transmission loss measured by the 52 m-2 m cut-back method at a wavelength of 650 nm and an incident numerical aperture (incidence NA) of 0.15 was 135 dB / km.

  The plastic optical fiber thus produced was wound 20 times around a stainless steel rod having a radius of 10 mm, ethanol having a content of 99.5% was dropped, and the occurrence probability of environmental stress cracks was examined. It occurred in 1 out of 10 pieces.

  Further, 3 m of a plastic optical fiber was taken, and 1 m 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 in the mixed solution were -10. 6 dBm and -10. The value after 3000 hours was not changed between -10.6 dBm and -10.7 dBm with respect to 7 dBm.

  Next, this plastic optical fiber was introduced into a crosshead die for covering electric wires, and at 210 ° C., nylon 12 was coated to a thickness of 250 μm to obtain a cable having a diameter of 1500 μm. The plastic optical fiber cable was removed by leaving 30 mm of the coating layer, and the pulling strength of the primary coating layer was measured through a hole having a diameter of 1.1 mm. The pull-out strength was 21N.

<Comparative 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, an orifice Under the conditions of a diameter of 2 mm and a length of 8 mm, 1.5 g / 10 min was used. As a sheath resin, a copolymer comprising 30% by mole of vinylidene fluoride, 57% by mole of tetrafluoroethylene, and 13% by mole of hexafluoropropene, a resin having a melt flow index of 6 g / 10 min and a refractive index of 1.36 Was used.

  The above core resin and sheath resin are introduced into a two-layer composite die and spun as in the examples described in JP-A-2001-174646, and a plastic optical fiber element having a core diameter of 980 μm and a sheath layer thickness of 10 μm and a diameter of 1000 μm Got a line. The transmission loss measured by the 52 m-2 m cutback method with a wavelength of 650 nm and an incident numerical aperture (incidence NA) of 0.15 was 138 dB / km.

  The plastic optical fiber thus produced was wound 20 times around a stainless steel rod having a radius of 10 mm, ethanol having a content of 99.5% was dropped, and the occurrence probability of environmental stress cracks was examined. It occurred in 9 out of 10 and 12 locations.

  Further, 3 m of this plastic optical fiber was taken, and 1 m was immersed in 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 Hacktronics, optical power meter PHOTO205), and the first value before immersion in the mixed solution was 48 with respect to 10.3 dBm. It became -10.8 dBm in time, and then it was disconnected. The second one was -10.9 dBm in 2000 hours with respect to the value before immersion of -10.4 dBm, and then disconnected.

<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, an orifice Under the conditions of a diameter of 2 mm and a length of 8 mm, 1.5 g / 10 min was used. As a first sheath resin, a modified fluororesin having a refractive index of 1.385, a melt flow index of 11 g / 10 min, a melting point of 166 ° C., and a Shore D hardness (ASTM D2240) of 67 (manufactured by Daikin Industries, Neofron) EFEP RP4020) was used. As the second sheath resin constituting the second sheath layer formed on the outer periphery of the first sheath layer (layer composed of the first sheath resin), 57 mol% of vinylidene fluoride, 32 mol of tetrafluoroethylene %, A copolymer of 11 mol% hexafluoropropene, having a refractive index of 1.36, a melt flow index of 8 g / 10 min, and a melting point of 120 ° C. was used.

  The core resin and sheath resin were introduced into a three-layer composite die, and the die temperature was spun at 240 ° C. The strand discharged from the die was stretched twice and heat-treated to obtain a plastic optical fiber having a core diameter of 960 μm, a first sheath layer thickness of 10 μm, and a second sheath layer thickness of 10 μm and a diameter of 1000 μm. The transmission loss of this strand was 134 dB / km.

  Next, this plastic optical fiber was introduced into a crosshead die for covering electric wires, and at 210 ° C., nylon 12 was coated to a thickness of 250 μm to obtain a cable having a diameter of 1500 μm. The pull-out strength was 70 N or higher when the strands started to stretch.

<Example 4>
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, an orifice Under the conditions of a diameter of 2 mm and a length of 8 mm, 1.5 g / 10 min was used. As the first sheath resin, tetrafluoroethylene 43 mol%, ethylene 41 mol%, hexafluoropropylene 15.5 mol%, perfluoro (1,1,5-trihydro-1-pentene) 0.5 mol% 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 monomer component, having a refractive index of 1.385 and a melt flow index of 11 g / 10 min, a modified fluororesin having a melting point of 166 ° C. and a Shore D hardness (ASTM D2240) value of 67 was used. As the second sheath resin constituting the second sheath layer formed on the outer periphery of the first sheath layer (layer composed of the first sheath resin), 57 mol% of vinylidene fluoride, 32 mol of tetrafluoroethylene %, A copolymer of 11 mol% hexafluoropropene, having a refractive index of 1.36, a melt flow index of 8 g / 10 min, and a melting point of 120 ° C. was used.

  The core resin and sheath resin were introduced into a three-layer composite die, and the die temperature was spun at 240 ° C. The strand discharged from the die was stretched twice and heat-treated to obtain a plastic optical fiber having a core diameter of 960 μm, a first sheath layer thickness of 10 μm, and a second sheath layer thickness of 10 μm and a diameter of 1000 μm. The transmission loss of this strand was 134 dB / km.

  Next, this plastic optical fiber was introduced into a crosshead die for covering electric wires, and at 210 ° C., nylon 12 was coated to a thickness of 250 μm to obtain a cable having a diameter of 1500 μm. The pull-out strength was 70 N or higher when the strands started to stretch.

  The plastic optical fiber and cable of the present invention have chemical resistance such as alcohols, fats and oils, waxes, lubricants, petroleums, etc., and have high reliability, in-vehicle wiring, FA equipment wiring, household equipment, etc. Even where there is a possibility of contact with chemicals, 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)

A plastic optical fiber having a core formed of a transparent resin and a sheath layer made of at least one layer of a modified fluororesin formed around the core,
The modified fluororesin has a melting point in the range of 150 to 200 ° C., the refractive index measured at 20 ° C. with sodium D line is 1.37 to 1.41, and the melt flow index (230 ° C., load 3. A plastic optical fiber, which is an ethylene-tetrafluoroethylene copolymer resin having a reactive functional group terminal, having a diameter of 8 kg, an orifice diameter of 2 mm, and a length of 8 mm) of 5 to 100 g / 10 min.   2. The plastic optical fiber according to claim 1, wherein the transparent resin is a polymethyl methacrylate resin.   The plastic optical fiber strand according to claim 1 or 2, wherein the modified fluororesin is a carbonate-modified ethylene-tetrafluoroethylene copolymer. The plastic optical fiber strand according to any one of claims 1 to 3,
A coating layer containing a thermoplastic resin formed on the outside of the plastic optical fiber;
A plastic optical fiber cable. The sheath layer comprises at least two layers,
The outermost layer of the sheath layer contains 40 to 62 mol% of vinylidene fluoride component, more than 28 mol% of tetrafluoroethylene component and 40 mol% or less, and 8 to 22 mol% of hexafluoropropene component. Made of polymer,
The plastic optical fiber cable according to claim 4, wherein the coating layer in contact with the outside of the outermost sheath layer contains a polyamide-based resin.

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