JP2011209487A - Plastic optical fiber cord - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic optical fiber cord that has long-term heat resistance by which it withstands the use at an actual use temperature of 105°C and is excellent in adhesion strength between a coating layer and a plastic optical fiber.SOLUTION: The plastic optical fiber cord has at least one coating layer in an outer layer of a plastic optical fiber having a core and at least one clad layer. The outermost clad of the plastic optical fiber is formed of a copolymer containing, as copolymerization components, 10-35 wt.% of ethylene, 44-69 wt.% of tetrafluoroethylene, 20-45 wt.% of hexafluoropropylene, and 0.01-10 wt.% of a fluorovinyl compound expressed by formula (1): CH=CX(CF)Xin which Xrepresents a fluorine atom or a hydrogen atom, Xrepresents a fluorine atom, a hydrogen atom or a hydrocarbon group, and n represents an integer of 1-10. The adhesion strength between the coating layer and the plastic optical fiber in a length of 30 mm is 50 N or more.

Description

  The present invention relates to a plastic optical fiber cord having at least one coating layer on the outer layer of a plastic optical fiber (hereinafter sometimes abbreviated as POF). More specifically, the present invention relates to a plastic optical fiber cord having long-term heat resistance that can withstand use at an actual use temperature of 105 ° C. and having excellent adhesion between a coating layer and the plastic optical fiber.

  Since POF is superior to glass-based optical fibers in terms of processability, handleability, and manufacturing cost, it is suitably used for short-distance optical communication transmission, photoelectric sensors, light guides, and the like. In particular, recently, a plastic optical fiber cord in which POF is coated with a thermoplastic resin such as nylon (polyamide) has been proposed as information communication wiring in an automobile.

  POF is composed of a core and a clad. Conventionally, a polymer excellent in transparency and weather resistance, typically polymethyl methacrylate (hereinafter sometimes abbreviated as PMMA), is used for the core. ing. On the other hand, the clad needs to have a lower refractive index than the core in order to confine light inside the core, and fluorine-containing polymers are widely used.

  For indoor wiring and in-vehicle information communication wiring applications, POF is often applied in a narrow space in a hot and humid environment, and has heat resistance, heat and humidity resistance, bending resistance, and bending loss resistance characteristics. Required. In particular, the wiring in an automobile roof or engine room has an environmental temperature as high as about 100 ° C. Therefore, the plastic optical fiber cord is also required to satisfy long-term heat resistance at a high temperature of 100 to 105 ° C. Yes.

  In addition, plastic optical fiber cords are usually used with a connector attached to the end. However, when peeling off the coating layer, the plastic optical fiber bare wire (elementary wire) is easily damaged. A mounting method is employed in which the connector parts are connected and fixed while remaining. When connecting and fixing the coating layer to the connector component, it is necessary that the adhesion between the bare plastic optical fiber (elementary wire) and the coating layer be high in order to maintain the connection strength between the connector component and the plastic optical fiber cord. . Therefore, a plastic optical fiber cable having a first coating layer made of a fluorine-containing polyolefin resin composition on the outside of a plastic optical fiber strand clad with a fluorinated methacrylate copolymer or a vinylidene fluoride copolymer is proposed. (For example, refer to Patent Document 1). However, this proposal has a problem that the long-term heat resistance in a temperature environment of 105 ° C. and the adhesion between the coating layer and the plastic optical fiber are insufficient.

  By the way, several techniques for improving the heat resistance of a plastic optical fiber cord using PMMA as a core and improving the adhesion between a clad and a covering material have been proposed.

  For example, the first cladding is made of a copolymer composed of 15 to 90% by mass of the fluoroalkyl (meth) acrylate unit (A) and 10 to 85% by mass of another copolymerizable monomer unit (B). 2. Description of the Related Art A plastic optical fiber cable in which a cladding is coated with a coating layer made of a polyamide-based resin composition on the outer periphery of a plastic optical fiber strand made of a fluorine-containing olefin-based resin containing a tetrafluoroethylene unit has been proposed (for example, , See Patent Document 2). However, in this proposal, the fluoroalkyl (meth) acrylate copolymer used as a clad material for plastic optical fibers is amorphous and has a high glass transition point, and a temperature environment of 105 ° C. as a plastic optical fiber strand. Although the heat resistance below is improved, it is not sufficient, and there is a problem that the adhesion between the coating layer and the plastic optical fiber is insufficient.

  Further, a plastic in which a cladding layer made of a thermoplastic resin is formed on the outer side of an optical fiber whose clad is composed of a terpolymer having a copolymerization ratio of 5-30 wt% ethylene, 40-75 wt% TFE, and 15-50 wt% HFP. An optical fiber cord has been proposed (see, for example, Patent Document 3). In this proposal, the ethylene / TFE / HFP copolymer used as a clad material has a low refractive index and a low crystallinity, and therefore has good translucency, but in a temperature environment of 105 ° C. There was a problem that the long-term heat resistance and the adhesion between the coating layer and the plastic optical fiber were insufficient.

  Further, a resin composition comprising at least a polyamide resin and a non-maleated polyolefin resin as constituents on the outside of a plastic optical fiber having a core made of a transparent resin and one or more fluororesin layers surrounding the core. A plastic optical fiber cord having a coating layer is proposed (see, for example, Patent Document 4). In this proposal, although the adhesion between the coating layer and the plastic optical fiber is improved, there is a problem that the long-term heat resistance in a temperature environment of 105 ° C. is insufficient.

Japanese Patent No. 3004845 (Claims) JP 2005-234135 A (Claims) JP 2001-074944 A (Claims) JP 2004-037979 A (Claims)

  Accordingly, an object of the present invention is to provide a plastic optical fiber cord having long-term heat resistance that can withstand use at an actual use temperature of 105 ° C. and having excellent adhesion between the coating layer and the plastic optical fiber.

That is, the present invention provides a plastic optical fiber cord having at least one coating layer on an outer layer of a plastic optical fiber having a core and at least one cladding, wherein the outermost cladding of the plastic optical fiber is made of ethylene 10 -35 wt%, tetrafluoroethylene 44-69 wt%, hexafluoropropylene 20-45 wt% and the following formula (1)
CH ₂ = CX ¹ (CF ₂ ) _n X ² (1)
(In formula (1), X ¹ is a fluorine atom or a hydrogen atom, X ² is a fluorine atom, a hydrogen atom or a hydrocarbon group, and n is an integer of 1 to 10) 0.01 to It is a plastic optical fiber cord that is made of a copolymer containing 10% by weight as a copolymerization component and has an adhesive force of 50 N or more between a coating layer and a plastic optical fiber at a length of 30 mm.

  According to the present invention, it is possible to provide a plastic optical fiber cord having long-term heat resistance that can withstand use at 105 ° C. and having excellent adhesion between the coating layer and the plastic optical fiber.

  The plastic optical fiber cord of the present invention has a core and at least one coating layer on the outer layer of the plastic optical fiber having at least one clad.

  The core material of the plastic optical fiber cord of the present invention is preferably a (co) polymer having methyl methacrylate (hereinafter sometimes abbreviated as MMA) as a main polymerization component. Specific examples include (co) polymers obtained by polymerizing a polymerization component containing 70% by weight or more of polymethyl methacrylate (PMMA) or MMA. Examples of the copolymer include a copolymer of MMA and acrylic acid ester, (meth) acrylic acid, (substituted) styrene and (N-substituted) maleimide, glutaric anhydride obtained by polymerizing them, Examples include modified polymers such as glutarimide. In the present invention, the (co) polymer represents a polymer and a copolymer. Similarly, (meth) acrylic acid ester represents acrylic acid ester and methacrylic acid ester.

  Examples of (meth) acrylic acid esters include methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenyl methacrylate, bornyl methacrylate, and adamantyl methacrylate. Examples of the substituted styrene include methyl styrene and α-methyl styrene. Examples of the N-substituted maleimide include N-isopropylmaleimide, N-cyclohexylmaleimide, N-methylmaleimide, N-ethylmaleimide, and N-o-methylphenylmaleimide. Two or more of these may be used, and a small amount of components other than these may be used.

  Further, the core material may contain a stabilizer such as an antioxidant in an amount that does not adversely affect the translucency.

  In the present invention, it is most preferable that the core material is substantially PMMA from the viewpoints of productivity, translucency and environmental resistance.

  The plastic optical fiber cord of the present invention has at least one clad. The clad may have two or more layers. For example, the first clad having a refractive index lower than that of the core and the second clad having a refractive index lower than that of the first clad are arranged in this order on the outer side of the core. It is done. By the second clad having a low refractive index, light leaking from the bent portion of the POF or the irregular portion of the first clad can be reflected and collected. Furthermore, a third clad having a lower refractive index than the second clad may be provided outside the second clad, and light leaking from the second clad can be reflected and collected. On the other hand, from the viewpoint of cost and productivity, the cladding is preferably two layers or less.

In the plastic optical fiber cord of the present invention, the outermost clad of the plastic optical fiber is composed of 10 to 35% by weight of ethylene, 44 to 69% by weight of tetrafluoroethylene, 20 to 45% by weight of hexafluoropropylene, and the following formula (1)
CH ₂ = CX ¹ (CF ₂ ) _n X ² (1)
(In formula (1), X ¹ is a fluorine atom or a hydrogen atom, X ² is a fluorine atom, a hydrogen atom or a hydrocarbon group, and n is an integer of 1 to 10) 0.01 to It is formed from a copolymer containing 10% by weight as a copolymerization component. The outermost clad refers to the clad when it has one layer, and refers to the outermost clad when it has two or more layers.

  When ethylene is less than 10% by weight in the copolymer component, the molding stability is lowered. When it exceeds 35% by weight, the crystallinity becomes high, the transparency is lowered, and the transmission characteristics are lowered. 11-30 weight% is preferable. When tetrafluoroethylene is less than 44% by weight, molding stability is lowered. When it exceeds 69% by weight, the crystallinity becomes high, the transparency is lowered, and the transmission characteristics are lowered. In addition, the melting point increases, and the fluidity near the spinning temperature of the optical fiber decreases. When hexafluoropropylene is less than 20% by weight, flexibility is lowered and bending loss is lowered. When it exceeds 45% by weight, the tackiness increases, so that the workability when coating the coating layer is lowered.

  In particular, in order to provide adhesion with the coating layer and long-term heat resistance, it is necessary to contain 0.01% by weight or more of the fluorovinyl compound represented by the above formula (1) in the copolymer component. On the other hand, the content is 10% by weight or less from the relationship with the content of other copolymer components.

  In the formula (1), examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and a pentyl group. As for carbon number, 1-5 are preferred.

Examples of the fluorovinyl compound represented by the formula (1) include CH ₂ ═CF (CF ₂ ) ₃ H, CH ₂ ═CH (CF ₂ ) ₃ H, CH ₂ ═CF (CF ₂ ) ₄ H, _{CH 2 = CH (CF 2)} 4 H, CH 2 = CF (CF 2) 3 CH 3, CH 2 = CF (CF 2) 3 C 2 H 5, CH 2 = CH (CF 2) 3 F , and the like It is done. Two or more of these may be used.

In particular, the following formula (2)
_{CH 2 = CF (CF 2)} 3 H (2)
Is preferable, and is excellent in productivity, cost, environmental performance, and transmission characteristics of the plastic optical fiber.

  The melt flow rate (hereinafter sometimes abbreviated as MFR) of the clad of the outermost layer of the plastic optical fiber cord of the present invention is 10 to 100 g / 10 min (conditions: temperature 265 ° C., load 5 kg, orifice diameter 2 mm). The length is preferably within the range of 8 mm). More preferably, it is 20-60 g / 10min. Since the extrusion becomes easy by setting the MFR within the above range, the spinning proceeds smoothly. Moreover, the adhesiveness with a core can be kept moderate, eccentricity becomes favorable, and the outer-diameter fluctuation | variation of a plastic optical fiber can be suppressed.

  In the present invention, the combination of the outermost cladding and at least one coating layer described later increases the interaction between the plastic optical fiber and the coating layer component. As will be described later, 30 mm of the plastic optical fiber cord is used. The adhesion between the coating layer and the plastic optical fiber in the length can be easily set to 50 N or more.

In the plastic optical fiber cord of the present invention, when the clad is one layer, the refractive index of the clad made of the copolymer is lower than that of the core, and the theoretical numerical aperture obtained from the refractive index of the core and the clad by the following formula (4) (NA) is preferably 0.51 to 0.65.
Theoretical numerical aperture = ((core refractive index) ² − (cladding refractive index) ² ) ^1/2 (4)
The numerical aperture of plastic optical fiber with PMMA as a core that has been put into practical use is around 0.45 to 0.65, and it is also put into practical use by setting the theoretical numerical aperture to 0.51 to 0.65. Compatibility with peripheral components such as the light emitting / receiving element can be maintained.

  When the plastic optical fiber cord of the present invention has two or more clads, the innermost clad is preferably made of a copolymer containing vinylidene fluoride and tetrafluoroethylene as copolymerization components. By using such a copolymer, the bending resistance and chemical resistance of the plastic fiber cord of the present invention and the adhesion to the core layer are improved.

The copolymer containing vinylidene fluoride and tetrafluoroethylene as a copolymer component is preferably (1) a copolymer containing 65 to 85% by weight of vinylidene fluoride and 15 to 35% by weight of tetrafluoroethylene as a copolymer component. (2) a copolymer containing 35 to 60% by weight of vinylidene fluoride, 35 to 60% by weight of tetrafluoroethylene, and 5 to 30% by weight of hexafluoropropylene as a copolymerization component, and (3) 10 to 35 of vinylidene fluoride. Examples thereof include a polymer containing, as a copolymerization component, wt%, tetrafluoroethylene 45 to 75 wt%, hexafluoropropylene 10 to 30 wt%, and perfluoroalkyl vinyl ethers 1 to 10 wt%. The perfluoroalkyl vinyl _{ethers, CF 2 = CFOCF 3, CF} 2 = CFOCF 2 CF 3, CF 2 = CFOCF 2 CF 2 CF 3, CF 2 = CFOCH 2 CF 3, CF 2 = CFOCH 2 CF 2 CF 3, _{CF 2 = CFOCH 2 CF 2 CF} 2 CF 3, CF 2 = CFOCH 3, CF 2 = CFOCH 2 the like CH ₃ and the like, in that it enables to reduce the cost of the raw _material, CF 2 = CFOCF _3, A compound selected from the group consisting of CF ₂ = CFOCF ₂ CF ₃ and CF ₂ = CFOCF ₂ CF ₂ CF ₃ is particularly preferably used. By using the copolymer (3), the shape stability at the time of molding and the fluidity at the time of melting can be further improved, and the transmission loss is improved.

  In the plastic optical fiber cord of the present invention, when the clad has two or more layers, the innermost clad is preferably made of a polymer containing perfluoroalkyl (meth) acrylate as a polymerization component. By using such a polymer, long-term heat resistance and moist heat resistance are further improved. When it has three or more clads, it is more preferable that all the clads other than the outermost layer are made of a polymer containing perfluoroalkyl (meth) acrylate as a polymerization component. In the present invention, perfluoroalkyl (meth) acrylate represents perfluoroalkyl acrylate and perfluoroalkyl methacrylate.

As the polymer containing perfluoroalkyl (meth) acrylate as a polymerization component, the following formula (3)
_{CH 2 = C (CH 3)} -COO (CH 2) m (CF 2) n R (3)
(In Formula (3), R is a fluorine atom or a hydrogen atom, m is 1 or 2, and n is an integer of 1 to 10.) Perfluoroalkyl methacrylate represented by 60 to 95% by weight and methyl methacrylate 5 to 40 It is preferable to use a copolymer containing% by weight as a copolymerization component. By using the perfluoroalkyl methacrylate represented by the above formula (3) as a copolymerization component, white turbidity and yellowing of the obtained copolymer are suppressed, the translucency of the plastic optical fiber cord is improved, and transmission loss is reduced. Can be reduced. Moreover, it is excellent in mechanical characteristics, and can improve long-term heat resistance and bending resistance.

Furthermore, the perfluoroalkyl methacrylate represented by the formula (3) is represented by the following formula (5):
_{CH 2 = C (CH 3)} -COOCH 2 (CF 2) p R (5)
(In formula (5), R is preferably a fluorine atom or a hydrogen atom, and p is an integer of 1 to 4).

  Polymers containing perfluoroalkyl (meth) acrylates preferably used in the present invention as polymerization components include (meth) acrylic acid esters other than MMA, methacrylic acid having alicyclic hydrocarbons in the ester, and (meth) acrylic. Acid, (substituted) styrene and (N-substituted) maleimide may be copolymerized within about 10% by weight.

Moreover, it is preferable that the theoretical numerical aperture (NA) of the POF using the inner layer clad is 0.45 to 0.52. By setting the numerical aperture to 0.45 to 0.52, it is possible to use a clad having a well-balanced physical property, which has been conventionally used for one layer, as it is as the innermost layer clad of the present invention. The theoretical numerical aperture is expressed by the difference in refractive index between the core and the first cladding as in the following equation.
Numerical aperture = ((refractive index of the core) ² − (refractive index of the first cladding) ² ) ^1/2

  Further, the plastic optical fiber cord of the present invention is a clad layer for further improving the adhesion between the coating layer and the plastic optical fiber, which will be described later, and for reducing the thermal damage that the plastic optical fiber receives when the coating layer is coated. Further, a clad layer or a coating layer may be provided around the periphery.

  The plastic optical fiber cord of the present invention has at least one coating layer on the outer layer of the plastic optical fiber. Two or more coating layers may be provided, and three or less are preferable.

  The coating layer is preferably composed of a thermoplastic resin or a thermoplastic elastomer. Examples of the thermoplastic resin include polyolefin resins, olefin resins containing an organic silane group, ethylene-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene fluoride, polyamide resins such as nylon 12, polyester resins, urethane resins, A fluororesin etc. are mentioned. The thermoplastic elastomer includes a structure in which a soft segment composed of a soft rubber component (soft phase) and a hard segment composed of a hard resin component (hard phase) are separated. The soft segment exhibits the property of being softly compositionally deformed, and the hard segment functions to prevent (restrain) plastic deformation like a crosslinking point of vulcanized rubber. Examples of the thermoplastic elastomer include polyamide elastomers such as nylon 12 elastomer, polyester elastomers, and polyolefin elastomers.

  In the present invention, the innermost layer of the coating layer in contact with the clad of the plastic optical fiber preferably contains a polyamide resin as a main component. When the innermost layer of the coating layer contains a polyamide resin as a main component, it is possible to improve oil resistance, wear resistance, heat resistance, and impact resistance, which are characteristics required for use in automobile information communication wiring. On the other hand, the outermost layer of the coating layer is preferably composed mainly of a polyamide resin and / or a polyamide elastomer. Thereby, oil resistance, abrasion resistance, heat resistance, impact resistance, and bending resistance, which are characteristics necessary for use in automobile information communication wiring, can be improved. In addition, the innermost layer of a coating layer refers to the said coating layer, when it has one coating layer, and when it has two or more coating layers, it points out the coating layer located in the innermost among them. The outermost layer of the coating layer refers to the coating layer when having one coating layer, and refers to the coating layer located on the outermost side when having two or more coating layers. In addition, “having a polyamide resin as a main component” means containing 50% by weight or more of a polyamide resin, and “having a polyamide resin and / or a polyamide elastomer as a main component” means adding the polyamide and the polyamide elastomer together. It means to contain 50% by weight or more. As the polyamide resin, those having nylon 12 as a main component are preferable, and examples include nylon 12 homopolymer and a copolymer containing 50% by weight or more of nylon 12 units. As the polyamide resin, a general commercial product having properties such as a flexural modulus of 1.0 to 2.0 GPa, a tensile yield strength of 30 to 55 MPa, and a deflection temperature under load (0.45 MPa) of 135 to 150 ° C. can be preferably used. Other characteristics may be used. The coating layer may contain other resins and elastomers, plasticizers, flame retardants, antioxidants, anti-aging agents, stabilizers such as UV stabilizers, carbon black for coloring, pigments And may contain dyes and the like.

  In the plastic optical fiber cord of the present invention, it is important that the adhesion between the coating layer and the plastic optical fiber in a length of 30 mm is 50 N or more. If the adhesive force is less than 50 N, when the plastic optical fiber cord is pulled out from the connector, the plastic optical fiber and the coating layer are peeled off and the end face of the plastic optical fiber is retracted, so that the reliability of optical coupling is lowered. Also, pistoning may occur due to environmental changes. Preferably it is 60N or more. On the other hand, in the case of a plastic optical fiber having an outer diameter of 1000 μm, the adhesion is preferably 100 N or less. If the adhesion is 100 N or less, the plastic optical fiber can suppress cutting.

  Here, the adhesion force between the coating layer and the plastic optical fiber at a length of 30 mm can be measured by the following method. The coating layer of the plastic optical fiber cord having a test length of 90 mm is peeled off by 60 mm, and the plastic optical fiber is exposed leaving only the coating layer by 30 mm. The exposed plastic optical fiber is passed through a metal plate having a hole 0.1 mm larger than the diameter of the plastic optical fiber, and the plastic optical fiber is pulled out at a tensile speed of 50 mm / min with a tensile tester. The diameter of the plastic optical fiber is generally 1000 μm. Measurement of n = 20 is performed, and the minimum value of the tensile yield strength is defined as the adhesion strength.

  The plastic optical fiber cord having an adhesion force of 50 N or more between the coating layer and the plastic optical fiber is, for example, 10 to 35% by weight of ethylene, 44 to 69% by weight of tetrafluoroethylene, 20 to 45% by weight of hexafluoropropylene, and the above formula A clad outermost layer formed of a copolymer containing 0.01 to 10% by weight of the fluorovinyl compound represented by (1) as a copolymerization component is combined with an innermost coating layer mainly composed of a polyamide resin. Therefore, it can be easily obtained.

  The plastic optical fiber cord of the present invention preferably has a bending resistance at a length of 100 mm of 8 N / mm or more. If the bending resistance is 8 N / mm or more, even when it is bent and arranged in an automobile, the influence of pressure applied to the side surface from peripheral parts and devices is small, and a reduction in light amount can be suppressed. .

  Here, the bending resistance at a length of 100 mm can be measured by the following method. A plastic optical fiber cord having a test length of 100 mm is arranged perpendicularly to the tensile direction, and is sandwiched by using a metal jig bent into a U shape. The tensile yield strength per 1 mm is measured when pulled 1 cm at a tensile speed of 5 mm / min with a tensile tester. Measurement of n = 10 is performed, and the lowest value of tensile yield strength is defined as bending resistance.

  The plastic optical fiber cord having a bending resistance of 8 N / mm or more is represented by, for example, ethylene 10 to 35% by weight, tetrafluoroethylene 44 to 69% by weight, hexafluoropropylene 20 to 45% by weight, and the above formula (1). It is easily obtained by combining a clad outermost layer formed by a copolymer containing 0.01 to 10% by weight of a fluorovinyl compound as a copolymer component and a coating layer innermost layer mainly composed of a polyamide resin. be able to. Since the clad outermost layer having the above composition is excellent in affinity with the coating layer, the resistance to bending can be increased.

  In order to achieve a bending resistance of 8 N / mm or more, the outermost cladding layer is composed of 10 to 35% by weight of ethylene, 44 to 69% by weight of tetrafluoroethylene, 20 to 45% by weight of hexafluoropropylene, and the above formula (1). It is preferably formed from a copolymer containing 0.01 to 10% by weight of the indicated fluorovinyl compound as a copolymerization component.

  In the plastic optical fiber cord of the present invention, the outer diameter of the plastic optical fiber is usually about 0.1 to 3 mm. Further, from the viewpoint of strength for wiring in an automobile and handleability, the core diameter is preferably 0.7 to 1.5 mmφ, and the cladding thickness is preferably 0.005 to 0.3 mm. Furthermore, when forming a protective layer in the circumference | surroundings, 0.005-0.5 mm is preferable.

  In the plastic optical fiber cord of the present invention, the thickness of the coating layer is preferably 0.05 to 30 mm.

  Next, the manufacturing method of the plastic optical fiber cord of this invention is demonstrated.

  First, a method for producing a plastic optical fiber having a core and at least one clad will be described. Such a plastic optical fiber can be manufactured by a conventional method. For example, a core / first clad / second composite spinning method in which a core material and a clad material are discharged from a composite die for concentric composites in a heated and melted state to form a core / clad two-layer core-sheath structure. A composite spinning method for forming a clad three-layer core-sheath structure is preferably used. In the case where a protective layer is provided, a composite spinning method is preferred in which the core material, the clad material, and the protective material are discharged from a composite die for concentric composites in a heated and melted state to form a core / clad / protective layer. . Subsequently, a stretching process of about 1.2 to 3 times is generally performed for the purpose of improving mechanical properties.

  Next, a method for manufacturing a plastic optical fiber cord will be described. A plastic optical fiber cord is obtained by forming the above-mentioned plastic optical fiber as a strand and forming at least one coating layer on the outer layer thereof by a method such as a melt extrusion method using a crosshead die. Preferably, a plastic optical fiber fed with a supply tension of 50 to 1400 g by a wire feeder or the like is fed from the rear part of the crosshead die, and the coating material in a heated and melted state extruded from the extruder in the die is a plastic optical fiber. There is a method of coating by fusing around. For the purpose of preventing a decrease in translucency due to an increase in the amount of heat received per unit time of the plastic optical fiber, a step of rapidly cooling and solidifying the coating material around the plastic optical fiber may be provided. The cooling medium used in the cooling step is generally water, but other cooling mediums may be used.

  Hereinafter, the present invention will be described in more detail with reference to examples. Evaluation was performed by the following method.

Melt flow rate (MFR) of the cladding material:
According to Japanese Industrial Standard JIS K7210, the amount discharged from the nozzle for 10 minutes was measured under the conditions of 265 ° C., load 5.0 kg, nozzle diameter 2 mm, and length 8 mm.

Transmission loss:
Measurement was performed by a 30/2 m cutback method using halogen parallel light (wavelength 650 nm, incident NA = 0.25). If it is 150 dB / km or less, it is a pass.

Adhesion:
The coating layer of a plastic optical fiber cord having a test length of 90 mm was peeled off by 60 mm, and the optical fiber was exposed leaving only the coating layer by 30 mm. The plastic optical fiber was passed through a metal plate having a hole 0.1 mm larger than the diameter of the plastic optical fiber, and the fiber was drawn at a tensile speed of 50 mm / min with a general commercial tensile tester, and the tensile yield strength was measured. The measurement of n = 20 was performed and the minimum value of the tensile yield strength was shown as the adhesion. If it is 50N or more, it is a pass.

Bending resistance:
A plastic optical fiber cord having a test length of 100 mm is arranged perpendicular to the tensile direction and is sandwiched by using a metal jig bent into a U shape, and is 1 cm at a tensile speed of 5 mm / min with a commercially available tensile tester. The tensile yield strength per 1 mm when pulled was measured. The measurement of n = 10 was performed and the minimum value of the tensile yield strength was shown as bending resistance. If it is 8 N / mm or more, it is acceptable.

Long-term heat resistance:
A plastic optical fiber cord having a test length of 28 m (1 m at each end is outside the oven) was placed in a high-temperature oven at 105 ° C. (PHH-200 manufactured by Tabai Espec) for 500 hours, and the amount of light before and after the treatment was measured. The measurement of n = 3 was performed, and the average value of the light amount change before and after the treatment was shown as long-term heat resistance (minus indicates a light amount decrease). If it is within -1.0 dB, it is a pass.

Moisture and heat resistance:
A plastic optical fiber coat of 28m of sample (1m at each end is outside the high-temperature and high-humidity tank) is placed in a constant temperature and humidity chamber (LH41-12A manufactured by Nagano Science Co., Ltd.) with a temperature of 85 ° C and a humidity of 85% for 500 hours. The amount of light was measured. The measurement of n = 3 was performed, and the average value of the amount of change in light quantity before and after the treatment was shown as moisture and heat resistance (minus indicates a decrease in light quantity). If it is within -1.0 dB, it is a pass.

Bending loss:
A 660 nm LED was used, a plastic optical fiber cord was wound 360 ° around a round bar having a metal radius of 10 mm, and the amount of light before and after brazing was measured. The measurement of n = 3 was performed, and the average value of the amount of change in light quantity before and after plating was shown as a bending loss (minus indicates a decrease in light quantity). If it is within -1.0 dB, it is a pass.

Refractive index:
An Abbe refractometer was used as a measuring device, and measurement was performed at room temperature and 25 ° C.

Number of continuous bends:
A load of 500 g is applied to one end of the plastic optical fiber cord, supported by a mandrel having a diameter of 30 mm, and the other end of the plastic optical fiber cord is continuously bent at an angle of 90 ° around the support point, and the cord is cut. The number of times until was measured. The measurement of n = 5 was performed, and the average value of the number of cuttings was defined as the number of continuous bending. If it is 50,000 times or more, it is a pass.

[Example 1]
As a clad material, ethylene (Et) / tetrafluoroethylene (4F) / hexafluoropropylene (6F) / monomer A (CH ₂ ═CF (CF ₂ ) ₃ H) having the composition shown in Table 1 is used as a copolymer component. The copolymer (refractive index 1.387) was fed to a compound spinning machine. Furthermore, PMMA (refractive index: 1.492) manufactured by continuous soul polymerization is supplied as a core material to a compound spinning machine, and the core and cladding are melt melt-spun at 235 ° C., and the fiber diameter is 1000 μm (core diameter). A plastic optical fiber having a thickness of 980 μm and a cladding thickness of 10.0 μm was obtained. The first cladding is the outermost cladding.

  On the outer layer of the obtained plastic optical fiber, nylon 12 (“Daiamide (registered trademark)” L1640 manufactured by Daicel-Evonik Co., Ltd.) having a tensile yield strength of 40 MPa and a melting point of 178 ° C. was melt-extruded under a linear velocity of 50 m / min. A plastic optical fiber cord was fused by the above method so that the outer diameter was 1.5 mm to form a first coating layer having a thickness of 1.5 μm. Further, a polyamide elastomer resin having a tensile yield strength of 25 MPa and a melting point of 178 ° C. is used as an outer layer of the outer layer so that the outer diameter becomes 2.3 mm by using a crosshead cable coating apparatus with a crosshead die under a linear velocity of 50 m / min. To form a plastic optical fiber cord. The first coating layer is the innermost coating layer, and the second coating layer is the outermost coating layer.

  The plastic optical fiber cord thus obtained was evaluated by the above evaluation method. The results are shown in Table 3. As can be seen from Table 3, transmission loss, adhesion, bending resistance, number of continuous bending, long-term heat resistance, heat and humidity resistance, and bending loss were all excellent.

[Examples 2 to 8]
A plastic optical fiber cord was obtained in the same manner as in Example 1 except that the first cladding or the second coating layer was changed as shown in Table 1 (however, all the fiber diameters were unified to 1000 μm). These plastic optical fiber cords were used for the same evaluation as in Example 1, and the results are shown in Table 3. In Examples 2 to 8, transmission loss, adhesion, bending resistance, number of continuous bending, long-term heat resistance, moist heat resistance, and bending loss were all excellent.

[Examples 9 to 12]
Two types of clad were used when the core and clad were melt-spun at the core and clad at 235 ° C., except that the second clad shown in Table 2 was provided around the first clad (however, the fiber diameter was all 1000 μm) Unification) A plastic optical fiber cord was obtained in the same manner as in Example 1. The second cladding is the outermost cladding. These plastic optical fiber cords were used for the same evaluation as in Example 1, and the results are shown in Table 3. Examples 9 to 12 were all excellent in moisture and heat resistance, adhesion, bending resistance, transmission loss continuous bending frequency, long-term heat resistance, and bending loss.

[Comparative Examples 1 and 3]
A plastic optical fiber cord was obtained in the same manner as in Example 1 except that the first cladding was changed as shown in Table 2 (however, all the fiber diameters were unified to 1000 μm). Adhesion and long-term heat resistance were insufficient.

[Comparative Example 2]
A plastic optical fiber cord was obtained in the same manner as in Example 9 except that the second cladding was changed as shown in Table 2 (however, all the fiber diameters were unified to 1000 μm). Adhesion and long-term heat resistance were insufficient.

[Comparative Example 4]
A plastic optical fiber cord was obtained in the same manner as in Example 2 except that the first coating layer was changed as shown in Table 2. Adhesion was insufficient.

Et: ethylene FVE: heptafluoropropyl vinyl ether PMMA: polymethyl methacrylate MMA: methyl methacrylate 4FM: 2,2,3,3-tetrafluoropropyl methacrylate 5FM: 2,2,3,3,3-pentafluoropropyl methacrylate 2F : Vinylidene fluoride 4F: Tetrafluoroethylene 6F: Hexafluoropropylene

  The plastic optical fiber cord of the present invention has long-term heat resistance that can withstand use at 105 ° C., and can suppress a decrease in light amount under high temperature conditions within −1.0 dB. Control parts such as automobile steering, brakes, ABS units, transmissions, and engines have a temperature rise to 105 ° C. Therefore, long-term heat resistance, coating layers, etc. The plastic optical fiber cord of the present invention having excellent adhesion to the plastic optical fiber can be suitably used. In addition, the plastic optical fiber cord of the present invention is preferably used for more stable use in in-vehicle information communication wiring applications such as audio, navigation, and monitor that are not currently required to have heat resistance up to 105 ° C. be able to.

Claims (11)

A plastic optical fiber cord having at least one coating layer on an outer layer of a plastic optical fiber having a core and at least one clad, wherein the outermost clad of the plastic optical fiber comprises 10 to 35% by weight of ethylene, tetra 44 to 69% by weight of fluoroethylene, 20 to 45% by weight of hexafluoropropylene, and the following formula (1)
CH ₂ = CX ¹ (CF ₂ ) _n X ² (1)
(In formula (1), X ¹ is a fluorine atom or a hydrogen atom, X ² is a fluorine atom, a hydrogen atom or a hydrocarbon group, and n is an integer of 1 to 10) 0.01 to A plastic optical fiber cord comprising a copolymer containing 10% by weight as a copolymer component and having an adhesion force of 50 N or more between a coating layer and a plastic optical fiber at a length of 30 mm. The plastic optical fiber cord according to claim 1, wherein a bending resistance at a length of 100 mm is 8 N / mm or more. The fluorovinyl compound is represented by the following formula (2)
_{CH 2 = CF (CF 2)} 3 H (2)
The plastic optical fiber cord according to claim 1, which is a compound represented by the formula: The plastic optical fiber according to any one of claims 1 to 3, wherein the plastic optical fiber has two or more clads, and the innermost clad is made of a copolymer containing vinylidene fluoride and tetrafluoroethylene as copolymerization components. code. The plastic optical fiber cord according to claim 4, wherein the innermost clad is made of a copolymer containing 65 to 85% by weight of vinylidene fluoride and 15 to 35% by weight of tetrafluoroethylene as a copolymerization component. 5. The plastic according to claim 4, wherein the innermost cladding is made of a copolymer containing 35 to 60% by weight of vinylidene fluoride, 35 to 60% by weight of tetrafluoroethylene and 5 to 30% by weight of hexafluoropropylene as copolymerization components. Fiber optic cord. The innermost clad contains 10 to 35% by weight of vinylidene fluoride, 45 to 75% by weight of tetrafluoroethylene, 10 to 30% by weight of hexafluoropropylene, and 1 to 10% by weight of perfluoroalkyl vinyl ethers as copolymer components. The plastic optical fiber cord according to claim 4, comprising a copolymer. The plastic optical fiber cord according to any one of claims 1 to 3, wherein the plastic optical fiber has two or more clads, and the innermost clad is made of a polymer containing perfluoroalkyl (meth) acrylate as a polymerization component. The innermost cladding is formed by the following formula (3)
_{CH 2 = C (CH 3)} -COO (CH 2) m (CF 2) n R (3)
(In formula (3), R is a fluorine atom or a hydrogen atom, m is 1 or 2, and n is an integer of 1 to 10.) Perfluoroalkyl methacrylate 60 to 95% by weight and methyl methacrylate 9. The plastic optical fiber cord according to claim 8, comprising a copolymer containing 5 to 40% by weight as a copolymer component. The plastic optical fiber cord according to any one of claims 1 to 9, wherein an innermost layer of the covering layer is mainly composed of a polyamide resin. The plastic optical fiber cord according to any one of claims 1 to 10, wherein the plastic optical fiber cord has two or more coating layers, and an outermost layer of the coating layer is mainly composed of a polyamide resin and / or a polyamide elastomer.