JP2007086250A - Manufacturing method of plastic optical material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing, with superior productivity, a plastic optical fiber cord to which a fine diameter and desired characteristics are imparted while disconnection, deformation or deterioration during the process is prevented. <P>SOLUTION: In a resin pot 42, a delivered POF 12 is coated on the outer circumference with a protective layer-forming resin 55a having a thermosetting property with a viscosity of 10-200 Pa S, and is then fed into a warm bath 43. Assuming that Tg is the glass transition temperature of a polymer constituting the POF 12, the POF 12 is immersed in warm water 61 adjusted to (Tg-50) to Tg (°C), thereby hardening by heat the protective layer-forming resin 55a to form a protective layer. As a result, a cord 10 with a fine diameter can be obtained to which protective layer characteristics are imparted such as fire retardancy without causing the POF 12 to be disconnected, deformed or deteriorated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a plastic optical material, and more particularly, to a method for producing a plastic optical material that can be used for an optical waveguide such as an optical fiber or an optical interconnection waveguide.

  Conventionally, optical materials that propagate light have been chemically stable and glass materials have been used because of their excellent properties such as transparency, moldability, and hardness. Optical waveguides such as optical interconnection waveguides, lenses, electronic components, and the like are manufactured. However, recently, plastic materials are used in place of optical glass because of advantages such as transparency, workability, and weight reduction. For example, in an optical fiber having a core composed of a core that propagates light and a clad that confines light, a plastic optical fiber (POF) is attracting attention as an alternative to the conventional silica-based optical fiber. Has been. This POF has a light transmission loss larger than that of silica-based optical fiber, but has advantages such as ease of connection due to large diameter, ease of terminal processing, and the need for a high-precision alignment mechanism. In addition, the cost of the connector part is low, or the danger from piercing disasters to the human body is low, and it is excellent in workability and layability due to high flexibility, and from the advantages such as vibration resistance and low price, Not only is it attracting attention for in-vehicle use, but its use as an extremely short distance and large capacity cable such as an internal wiring of a high-speed data processing device or a DVI (Digital Visual Interface) link is also being studied. In addition, utilization as an optical HDMI link cable conforming to the High Definition Multimedia Interface (HDMI) standard is also being studied.

  Generally, such a POF is used as a plastic optical fiber cord (hereinafter referred to as a cord) by providing one or more protective layers made of resin on the outer periphery thereof. If a protective layer is provided on the outer periphery of the POF in this way, the mechanical properties such as the bending strength and tensile strength of the POF and the weather resistance are improved, the moisture resistance is improved, the deterioration of performance is suppressed, flame resistance is imparted, and chemical damage is caused. Protection, noise prevention by external light, and improvement of commercial value by coloring can be realized.

  In general, the method of forming a protective layer on the outer periphery of POF follows the method of applying an electric wire made of metal (hereinafter referred to as a metal electric wire), and transports a protective layer forming resin such as a thermoplastic resin. A method is used in which the resin is melt-extruded on the outer periphery of the POF and then cured (see, for example, Patent Document 1). However, unlike metal wires, POF is vulnerable to heat, and therefore, when the temperature of the molten resin used for coating is high, problems such as deformation and deterioration of the material constituting the POF occur. Therefore, when a resin or the like is applied to the outer periphery of the POF, it is necessary to pay attention to the selection of the protective layer forming resin and the temperature at the time of application.

  For example, when a polyvinyl chloride resin (PVC) is used as the protective layer forming resin, PVC requires a melt extrusion temperature of about 180 to 230 ° C. However, at this temperature, part of the POF melts and the shape is disturbed, resulting in an increase in transmission loss. In addition, such a resin having a high melting temperature often has a high viscosity. However, when such a high-viscosity resin is used as the protective layer-forming resin, a high pressure is often required during coating, and the pressure causes deformation such as cutting or stretching of the POF. The problem is that the loss increases. Further, if an attempt is made to increase the coating speed for the purpose of improving productivity, a difference occurs between the resin extrusion speed and the POF conveyance speed. In order to reduce this difference, improvement in the extrusion speed or reduction in the conveyance speed due to a decrease in the resin viscosity can be considered. However, in the former case, when the temperature is increased to lower the viscosity, the deformation of the POF or It causes deterioration. On the other hand, in the latter case, the protective layer is wound with insufficient curing due to insufficient cooling of the applied resin, and as a result, problems such as an increase in transmission loss of the resulting cord occur in a chain, resulting in a vicious circle Will cause. Therefore, at present, for example, when a protective layer is provided on a PMMA-based POF, in order to suppress deformation and deterioration of the POF, the protective layer-forming resin is melted at about 120 ° C. and has excellent flow at this temperature. High fluidity low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc. which show the property are used. However, this causes new problems such as limitation of the protective layer forming resin.

In addition, as described above, a cord with a protective layer provided on the outer periphery of the POF to improve its characteristics is laid on the electrical wiring of outdoor or apartment buildings, but the cord has excellent mechanical properties. And flame retardancy are required. However, in order to avoid various problems when forming the protective layer as described above, at present, the first protective layer is provided once by LDPE, LLPDE, etc., and deformation and deterioration due to heating at the time of coating are suppressed. Then, after improving the heat resistance of the POF, an operation of securing a desired characteristic by providing a second protective layer with PVC, chlorinated PVC, or the like is performed. And generally, a 2nd protective layer is formed with resin which adds a flame retardant to resin which forms a 2nd protective layer, or shows a flame retardance. In addition, as a flame-retarding technology for polyethylene, a polyethylene resin composition (for example, refer to Patent Document 2) in which a predetermined amount of a hydrated metal compound, a phosphate ester and red phosphorus are blended with polyethylene, a bromine compound or an antimony compound is used. A resin composition provided with an added protective layer has been proposed (see, for example, Patent Document 3). In addition, a flame retardant resin composition using a predetermined flame retardant has been proposed (see, for example, Patent Document 4).
JP 2001-174777 A JP-A-5-093097 JP-A-6-329847 WO2003 / 046083 "Flame-retardant resin composition"

  However, when the cord must be laid on an electronic substrate in a very narrow space or in a laying pipe, the method of forming the second protective layer on the first protective layer as described above provides a small-diameter cord. Is difficult. Therefore, it is desired to establish a manufacturing method that can produce a cord having characteristics such as excellent flame retardancy by forming only one protective layer on the outer periphery of the POF. Moreover, although patent document 3 can acquire the outstanding flame-retardant effect, the bromine compound and antimony compound which are used have a danger of causing environmental pollution etc., and there exists a problem in using. Further, in Patent Document 4, an excellent flame retardancy effect can be obtained. However, since a glass short fiber or glass flake is contained in a resin imparting flame retardancy, such a resin is used as a POF. If it is applied to the outer periphery, short glass fibers and flakes may contact the POF unevenly, causing local distortion and increasing transmission loss, which is not preferable.

  The present invention can provide a protective layer on the outer periphery of an optical waveguide containing POF without causing a decrease in productivity and deformation or deterioration of the optical waveguide, and has excellent flame retardancy and optical characteristics. It aims at providing the manufacturing method which can manufacture material.

  In order to solve the above-mentioned problems, a method for producing a plastic optical material according to the present invention is a method for producing a plastic optical material in which a protective layer is provided on an optical waveguide made of a polymer, and the viscosity is 10 to 200 (Pa · S). A coating step in which a protective layer forming material is applied to the outer periphery of the optical waveguide by passing the optical waveguide through the layer forming material, and a protective layer forming material applied in the coating step when the glass transition temperature of the polymer is Tg And a protective layer forming material curing step for curing at a temperature of (Tg-50) to Tg (° C.).

  In the coating step, it is preferable to pressurize the container filled with the protective layer forming resin and to extrude the protective layer forming material to the outer periphery of the strand by this pressurization. Moreover, it is preferable that a protective layer does not contain either a chlorine compound, a bromine compound, an antimony compound, a cadmium compound, a lead compound, a chromium compound, a zinc compound, or a tin compound. And when an optical waveguide consists of the area | region which has a some glass transition temperature, it is preferable to make said glass transition temperature into said Tg among the glass transition temperatures of this some area | region.

  Moreover, it is preferable that time T1 required for hardening of a protective layer forming material is 1 second or more and 60 minutes or less. The optical waveguide is a plastic optical fiber, and the outer diameter of the plastic optical fiber including the protective layer is preferably 1.5 mm or less.

  When the present invention is used for manufacturing a cord from POF, a cord having excellent flame retardancy and optical properties is manufactured by providing a protective layer on the outer periphery of the POF without causing a decrease in productivity and deformation or deterioration of the POF. can do. And since this invention uses resin for protective layer formation of a predetermined | prescribed viscosity under normal temperature normal pressure, it has advantages, such as easy temperature control of resin. In addition, since a resin having a relatively low viscosity is used as the protective layer forming resin, a high pressure is not required when the resin is transferred during coating. In addition, since liquid resin is used at the time of application, it is possible to transfer by compressed air. By using a protective layer forming facility using such a transfer function, it is possible to reduce power consumption by reducing energy. it can.

  Embodiments to which the present invention is applied will be described below with reference to the drawings. In the present embodiment, a plastic optical fiber cord (hereinafter referred to as a cord) is manufactured as an optical material. However, the present invention is not limited to the present embodiment, and can be applied to, for example, manufacturing an optical interconnection waveguide. FIG. 1 is a manufacturing process diagram of a cord. Only the process flow will be described here.

  The cord 10 of the present invention is obtained by providing a protective layer on the outer periphery of the POF 12 obtained by drawing the preform 11. Therefore, the manufacturing process of the cord 10 includes a preform forming process 15, a drawing process 16, and a protective layer forming process 17.

  In the preform forming step 15, the preform 11 is produced. The preform 11 of the present invention has a core part and a clad part. The method for manufacturing the preform 11 is not particularly limited, and any method known as a method for manufacturing the preform 11 can be applied. For example, there is a method described in Japanese Patent No. 3332922, and this embodiment uses this method. First, a cylindrical clad part forming an outer shell part is formed by a desired resin composition (in this embodiment, PVDF is used) by commercially available melt extrusion molding. And after inject | pouring the resin composition (this embodiment uses PMMA-d8 as a main component in this embodiment) which forms a core part inside this clad part, this resin composition is polymerized by the interfacial gel polymerization method. A core part is formed. In addition to the above, the preform 11 is produced by sequentially injecting a polymerizable composition having a different refractive index after polymerization into the inside of the clad portion, and repeating the polymerization step to form the core portion. This is also applicable to the present invention.

  Next, in the drawing step 16, the preform 11 is drawn to produce the POF 12. The drawing step 16 is a step of reducing the diameter of the preform 11 by stretching it in the longitudinal direction in a state where the preform 11 is heated and melted. By controlling the stretch ratio of the preform 11 in the drawing process 16, the POF 12 having a desired diameter can be manufactured.

  Note that the heating temperature of the preform 11 in the drawing step 16 is appropriately determined according to the material of the preform 11 and the like. It is preferable to set the heating temperature to 180 to 280 ° C., since it can be easily stretched while suppressing deformation and deterioration of the preform 11. Stretching conditions such as heating temperature, stretch ratio, and drawing tension may be appropriately determined in consideration of the diameter of the preform 11, the material, the diameter of the target POF 12, and the like, and are not particularly limited. For example, as described in Japanese Patent Application Laid-Open No. 7-234322, the drawing tension is set to 0.1 N or more in order to orient the molten plastic, or described in Japanese Patent Application Laid-Open No. 7-234324. Thus, in order not to leave distortion after melt drawing, it is preferable to make it 1N or less. Further, as described in JP-A-8-106015, a method of preheating the preform 11 in advance at the time of stretching can also be applied. The POF 12 obtained as described above has an elongation at break and hardness as defined in JP-A-7-244220 and is excellent in mechanical properties.

  In the protective layer forming step 17, the cord 10 is manufactured by providing a protective layer on the outer periphery of the POF 12. The protective layer forming step 17 includes a coating step 18 for applying a protective layer forming resin and a curing step 19 for curing the resin to form a protective layer.

  In the application step 18, a protective layer forming resin is applied to the outer periphery of the POF 12. Next, in the curing step 19, the resin is heated and cured to form the protective layer 20 to manufacture the cord 10. In the present embodiment, one protective layer 20 is provided on the outer periphery of the POF 12, but two or more protective layers may be provided if the outer diameter of the POF 12 is within a predetermined range. In this case, the protective layer forming step 17 may be repeated until a desired number of protective layers are obtained. Details of the protective layer forming step 17 will be described later.

  One or more of the manufactured cords 10 are bundled in the combining step 21, and then the outer periphery thereof is covered with a covering material in the covering step 22, so that a plastic optical fiber cable (hereinafter referred to as a cable) 23 can be obtained. . In addition, when the cord 10 and the tensile wire are bundled together in the combining step 21, a cable 23 having toughness can be obtained. Details of the cable 23 will be described later.

  FIG. 2 shows a cross-sectional view in the radial direction of the cord 10 obtained by the present invention. The cord 10 includes a POF 12 including a core portion 30 and a cladding portion 31 and a protective layer 20 provided on the outer periphery thereof. The clad portion 31 includes an inner clad 31a and an outer clad 31b.

  The POF 12 is a portion that becomes a core wire of the cord 10, and propagates light by reflecting light incident inside the core portion 30 at an interface with the cladding portion 31 having a different refractive index. When the thickness of the protective layer 20 is t1 (mm), t1 is preferably 0.2 to 3 mm. More preferably, t1 is 1 to 2 mm. When two or more protective layers 20 are provided, the outer diameter of the protective layer that is the outermost layer among the plurality of protective layers 20 is t1. Thereby, since the characteristic (for example, toughness, a flame retardance, etc.) of the material which comprises the protective layer 20 can fully be reflected with respect to POF12, the code | cord | chord 10 with which the desired characteristic was provided is obtained. Can do. However, if the thickness t1 of the protective layer 20 is less than 0.2 mm, the effect of forming the protective layer 20 may not be obtained. On the other hand, when t1 is thicker than 3 mm, there is a possibility that problems such as slow progress of curing of the resin for forming the protective layer 20 and generation of unreacted parts may occur.

  When the outer diameter of the POF 12 is D1 (mm), it is preferable to satisfy D1 of 0.2 to 1.0 mm because a cord 10 capable of fine wiring can be obtained. However, D1 is not particularly limited, and may be appropriately determined according to the application. In addition, when the diameter of the core part 30 is set to D2 (mm), it is preferable that D2 is 0.1-1 mm.

  In the present invention, when the outer diameter of the cord 10 is D3 (mm), the thickness and size of each member are adjusted so that D3 is 1.5 mm or less. Thereby, even the cord 10 having the protective layer 20 having a desired number of layers or thickness can be laid on an electronic substrate in a very narrow space or in a laying pipe.

  Further, the core part 30 of the present embodiment has a refractive index higher than that of the clad part 31 and has a refractive index that continuously increases from the boundary toward the center, and is a GI POF. The POF 12 having such a multi-layer structure may be produced by melting and extruding a material for forming each member at once by a melt extrusion method, or after forming a cylindrical clad portion 31 by a melt extrusion method in advance. Alternatively, it may be formed by injecting a material for forming the core portion 30 on the inner side and then polymerizing the material. However, when the materials for forming each member are extruded at a time by the melt extrusion method as in the former, a plurality of molten resins having different concentrations of refractive index adjusting agents (dopants) that cause each material to exhibit a difference in refractive index. Are arranged concentrically and extruded. In the radial direction of the circular cross section, the difference between the maximum value and the minimum value of the refractive index is preferably 0.001 or more and 0.3 or less. When the material for forming the core portion 30 is polymerized as in the latter case, it is preferable to use a rotational polymerization method because the work can be performed while realizing an excellent degree of polymerization of the material. The POF 12 only needs to have a distribution in which the refractive index increases toward the center of the diameter, and the form is not particularly limited. Such POF12 expresses a function as a GI-type POF.

  In addition, the form of the core part 30 and the clad part 31 is not limited to FIG. For example, in addition to the structure shown in FIG. 2, the core part 30 may have a multi-step index type having a multilayer structure of three or more layers, or the inner circumference of the clad part 31 without a boundary in the core part 30. A structure in which the refractive index increases continuously or stepwise from the center toward the center of the core portion 30 can be given. On the other hand, the clad part 31 may have, for example, a single-layer structure as necessary. As described above, the POF 12 of the present invention can be applied to any type of SI type and GI type. However, by using the GI type POF as in this embodiment, the POF 12 is lighter than the SI type. A code 10 having excellent transmission characteristics can be obtained.

  In FIG. 3, the schematic of the protective layer formation equipment used in this embodiment is shown. In the present embodiment, the cord 10 is manufactured by providing one protective layer on the outer periphery of the POF 12 manufactured in advance. Therefore, the protective layer forming facility 40 includes a POF delivery device 41, a coating device 42, a hot tub 43, a pair of take-up rollers 44, and a winding device 45. In addition, this invention is not limited to embodiment shown here.

  The POF delivery device 41 includes a POF delivery reel 50 and a dancer arm 51a having a pulley 51 at the tip. A POF roll is installed on the POF delivery reel 50, and the POF 12 is continuously sent from the POF delivery device 41 to the coating device 42 while rotating the POF roll and adjusting the alignment of the POF 12 by the pulley 51.

  The coating device 42 has a resin pot 55 and a die 56. The resin pot 55 is a container filled with a protective layer forming resin 55a that satisfies a predetermined viscosity range, and this protective layer forming resin 55a is appropriately supplied from a resin supply device (not shown) connected to the resin pot 55. The desired amount is supplied. When a gas supply device (not shown) is connected to the resin pot 55 and a clean and dry inert gas is supplied to the top of the resin pot 55, the liquid level of the resin 55a stored inside the resin pot 55 is increased. This is preferable because it can suppress thickening and adhesion of dust to the liquid surface.

  The POF 12 is coated with the protective layer forming resin 55a on the outer periphery while being transported inside the resin pot 55. After the application, the excessively applied protective layer forming resin 55 a is removed in the die 56. As a result, the POF 12 carried out from the die outlet 56 a becomes a coated POF 85 to which a desired amount of the protective layer forming resin 55 a has been applied, and is conveyed to the curing step 19.

The tension applied to the POF 12 when it is transported inside the coating apparatus 42 is preferably 700 N / cm ² or less in order to prevent deformation and tearing. The transport tension is more preferably as small as possible within a predetermined range, but is not particularly limited. Moreover, it is preferable that the conveyance speed V (cm / min) of POF12 is 10-10000 cm / min. More preferably, V is 50 to 6000 cm / min, and particularly preferably V is 100 to 5000 cm / min. As a result, the protective layer forming resin 55a can be applied substantially uniformly to the outer periphery of the POF 12, and the production speed of the cord 10 is a satisfactory value. Therefore, excellent productivity without incurring production time and the like. Thus, the cord 10 can be manufactured.

  However, the protective layer forming resin 55a used in the present invention has a viscosity P (Pa · S) satisfying 10 to 200 Pa · S. More preferably, the viscosity P is 50 to 200 Pa · S, and particularly preferably 100 to 200 Pa · S. When the protective layer forming resin 55a satisfying such a viscosity range is used, it is not necessary to perform temperature control at a high temperature. That is, since the management temperature may be relatively low, the management is easy, and the energy cost can be reduced by not requiring a high temperature. Further, since the coating operation can be performed at a relatively low temperature, the protective layer 20 having desired characteristics can be formed at a time, and as a result, the small-diameter cord 10 can be obtained. However, if the viscosity of the protective layer-forming resin 55a is less than 10 Pa · S, the fluidity is too high, so that dripping occurs when applied to the outer periphery of the POF 12, and a coating layer having a desired thickness is formed. Is difficult to form. On the other hand, if the viscosity exceeds 200 Pa · S, the fluidity is too low, which may cause uneven coating, which is not preferable. In this embodiment, as the protective layer forming resin 55a, a one-component low-temperature thermosetting urethane elastomer having a viscosity of 160 Pa · S (manufactured by Sunstar Giken Co., Ltd., freely molded elastomer “PENGUIN FOAM” RD10336C) is used. ing.

  When the viscosity P of the protective layer forming resin 55a satisfies the above range, the protective layer forming resin 55a can be transferred by compressed air from the air pressure regulator. Further, it is liquid even in the normal temperature region, and it is not necessary to heat melt the resin or to provide a heat retaining mechanism in the transfer flow path, which is preferable because energy costs can be reduced and equipment can be simplified.

  The applied POF 60 is fed into a hot tub 43 filled with hot water 61. A temperature adjusting device 63 is connected to the hot tub 43, and the temperature adjusting device 63 circulates the hot water 61 so that the temperature is controlled to a desired temperature. In this embodiment, the temperature is controlled to 80 ° C. It is preferable to circulate the hot water 61 in the hot tub 43 in this way because the temperature of the hot water 61 can be kept substantially uniform. Then, the coated POF 60 is supported by the pulley 62 disposed inside the hot tub 43 and conveyed inside the hot tub 43. As a result, the protective layer forming resin 55a is cured to such an extent that the fluidity disappears and a protective layer is formed, so that the cord 10 having the protective layer 20 formed on the outer periphery of the POF 12 is obtained. When the coated POF 60 is transported inside the hot tub 43, a transporting means such as a roller can be used instead of the pulley 62.

  In this embodiment, the protective layer forming resin 55a is cured by being immersed in the warm water 61. However, since the protective layer forming resin 55a satisfying a predetermined viscosity range is used, the protective layer forming resin 55a is relatively low in temperature. Even if the operation is performed in the warm water 61, the curing of the protective layer forming resin 55a can be sufficiently promoted. Further, when the hot tub 43 using the hot water 61 is used as a curing device, the protective layer forming resin 55a can be uniformly heated and cured, so that uneven curing is less likely to occur. This is preferable because the management of temperature, heat insulation and adjustment is easy.

  However, when the protective layer forming resin 55a is cured, when the glass transition temperature of the polymer constituting the POF 12 is Tg (° C.), the temperature around the coated POF 60 is (Tg-50) to Tg ° C. Fill the range. More preferably, it is (Tg-40) -Tg (degreeC), Most preferably, it is (Tg-30) -Tg (degreeC). That is, in this embodiment, the temperature of the hot water 61 in the hot tub 43 is adjusted so as to satisfy the above range. Therefore, in this embodiment, since the POF 12 having a Tg of about 90 ° C. at the center portion is formed, the temperature of the hot water 61 is adjusted to be 80 ° C. As a result, the curing of the protective layer forming resin 55a can be promoted in a short time, thereby realizing reduction of non-standard products and shortening of working time due to uncured or non-uniform curing of the protective layer forming resin 55a. be able to.

  However, when the curing temperature is less than (Tg-50) ° C., a material having a low curing temperature has a short pot life and is not preferable because curing starts in the pot. In addition, although the form which installed one hot tub 43 as a hardening apparatus was shown in this embodiment, you may arrange | position two or more. Thus, when using a some hardening apparatus, you may adjust so that it may become respectively different temperature, and you may adjust so that it may become the same temperature.

  Further, when the POF 12 is made of a plurality of polymers and there are a plurality of regions having glass transition temperatures, the lowest glass transition temperature among the glass transition temperatures of the plurality of regions is set as Tg, and the temperature is set in the curing step 19. It shall be used when In addition, when the polymer which comprises POF12 does not have a glass transition temperature, a thing with the lowest phase transition temperature (for example, melting | fusing point etc.) is made into Tg (degreeC).

  Further, the time required for the protective layer forming resin 55a to cure, that is, the time T1 required from when the coated POF 60 is immersed in the hot water 61 from the inlet 43a of the hot tub 43 to when it is carried out from the outlet 43b is: 1 second to 10 minutes. More preferably, T1 is 1 second or more and 3 minutes or less. T1 may be appropriately selected within a predetermined range in consideration of the type of the protective layer forming resin 55a and the thickness of the protective layer 20. When the curing time of the protective layer forming resin 55a satisfies the above range, the thickness of the protective layer 20 can be easily controlled. However, if the curing time is less than 1 second, uneven curing may occur when the protective layer 20 is thickened. On the other hand, if a material having a curing time exceeding 600 seconds is used, the POF 12 is exposed to warming conditions for a long time.

  In this embodiment, the hot water 61 is used to cure the protective layer forming resin 55a. However, the present invention is not limited to this. For example, the temperature adjusted to a desired temperature range on the outer periphery of the coated POF 60 is not limited thereto. A blowing device that cures the protective layer forming resin 55a by blowing air, a temperature control device that can be heated to a desired temperature, or the like may be used.

  Hereinafter, materials that can be used as the protective layer forming resin 55a are specifically exemplified. As the protective layer forming resin 55a, it is preferable to use a rubber having a high elastic modulus which is one form of a polymer because excellent mechanical properties (for example, bending strength) can be imparted.

  As the protective layer forming resin 55a, it is possible to use a liquid rubber that exhibits excellent fluidity at room temperature and has a property that the fluidity disappears and cures when heated. As the liquid rubber, for example, the basic structure is a polydiene type such as polyisoprene, polybutadiene, butadiene-acrylonitrile copolymer, and polychloroprene, for example, the basic structure is a polyolefin type such as poly (oxypropylene), for example, the basic structure is poly ( Examples thereof include polysulfide systems such as oxyalkylene disulfide), for example, polysiloxane systems whose basic structure is poly (dimethylsiloxane).

  What hardens | cures the liquid which mixed the material used as a polymer precursor, the reaction material, etc. can also be used as resin 55a for protective layer formation. Examples thereof include a one-component thermosetting urethane composition produced from an NCO block prepolymer and a fine powder coating amine described in JP-A-10-158353. In addition, a one-component thermosetting urethane composition comprising an NCO group-containing urethane prepolymer described in WO95 / 26374 and a solid amine of 20 μm or less can also be used.

  In addition, the above materials that can be used as the protective layer forming resin 55a include additives such as flame retardants, antioxidants, radical scavengers, lubricants, inorganic compounds, and organic compounds for the purpose of improving performance. The filler containing these etc. can be added suitably. For example, when a flame retardant is added to the protective layer forming resin 55a, flame retardancy can be imparted to the POF 12, and as a result, the cord 10 exhibiting excellent flame retardancy can be produced.

  However, the protective layer forming resin 55a is characterized by not containing any of a chlorine compound, a bromine compound, an antimony compound, a cadmium compound, a lead compound, a chromium compound, a zinc compound, and a tin compound. Since these compounds can become environmental pollutants, if they are contained in the protective layer 20, they may be contaminated to the outside environment by leaching to the outside, which is not preferable.

  The cord 10 on which the protective layer 20 is formed is taken out from the hot tub 43 by the pair of take-up rollers 44 while being supported by the support roller 65. A first moisture removing device 70 and a second moisture removing device 71 are provided between the support roller 65 and the take-up roller 44. The inside of the first moisture removing device 70 is provided with a blowing function, and wind is blown onto the cord 10 carried out of the hot tub 43 to wipe away moisture present on the surface of the cord 10. Further, the second moisture removing device 71 is provided with a suction function, and the moisture removal of the cord 10 is more effectively promoted by sucking the outer periphery of the cord 10 whose moisture has been wiped away by blowing air.

  In addition, an appearance inspection device and an outer diameter measuring device (both not shown) are arranged on the downstream side of the second moisture removing device, and presence or absence of lumps due to aggregation of the protective layer forming resin 55a on the surface of the cord 10 and It is preferable to determine whether or not a desired value is obtained by measuring the outer diameter of the cord 10 because it is possible to efficiently determine whether or not the product is a nonstandard product during manufacture of the cord 10.

  A motor 44 a is attached to one of the pair of take-up rollers 44. And the tension | tensile_strength at the time of taking out the code | cord | chord 10 is controlled by adjusting this motor 44a. The other take-up roller 44 is provided with a pressing member 44b. Thereby, the conveyance stability of the code | cord | chord 10 can be improved and it can work. In addition, although the form which uses the spring as the pressing member 44b is shown in this embodiment, what is necessary is just a member which can press the take-up roller 44, and it does not specifically limit.

  Inside the winding device 45, a support roller 75 and a winding roll 76 are provided. And the code | cord | chord 10 which supported by the support roller 75 and improved conveyance stability is wound up by the winding roll 76 sequentially, and is set as a cord product. In the present embodiment, the form of winding on the winding roll 76 is shown, but it is possible to cut the sheet into a desired shape and dimensions as it is without winding, and use it as a product.

  A plastic optical fiber cable (Plastic Optical Cable) 23 can be obtained by appropriately bundling the cord 10 on which the protective layer 20 is formed. In the present invention, a single cord 10 is used and, if necessary, the outer periphery thereof is further coated with a coating material is referred to as a single fiber cable. Further, after a plurality of cords 10 are assembled together with a tension member or the like, a cord whose outer periphery is covered with a coating material is referred to as a multi-fiber cable. The plastic optical fiber cable 23 includes both the single fiber cable and the multi-fiber cable.

  A material for forming the POF 12 will be described. Of the POF 12 forming materials that can be preferably used in the present invention, a material for forming the core portion 30 is an organic material having high light transmittance, and it is preferable to use this organic material as a molten resin. The material is not particularly limited as long as the function of optical transmission is not impaired, but it is preferable to use, as the main component, a polymer made of (meth) acrylic acid ester as the molten resin. Details of these materials will be described later. The clad part 31 has no problem as long as a material having a lower refractive index than that of the core part 30 is used. However, when a fluorine-based resin is used for the clad part 31, a low refractive index and an optically no problem can be easily obtained. Can be manufactured.

  In addition, as a forming material of the clad part 31, as described above, the refractive index is lower than that of the core part 30 so that the light transmitted through the core part 30 is totally reflected at the interface between the core part 30 and the clad part 31. A polymer is preferred. The material for forming the core part 30 and the clad part 31 is preferably an amorphous polymer so as not to cause light scattering. Further, the material is excellent in adhesion to each other and is shown in toughness. It is more preferable that the mechanical properties are excellent and the heat and humidity resistance is also excellent.

  Further, for the purpose of preventing moisture from entering the core portion 30 as much as possible, it is preferable to use a material having a low water absorption rate as the material for forming the outer cladding 31a. For example, the outer clad 31a is preferably mainly composed of a polymer having a saturated water absorption rate of less than 1.8%. More preferably, the outer clad 31a is formed of a polymer having a saturated water absorption rate of less than 1.5%, particularly preferably a saturated water absorption rate of less than 1.0%. Here, the saturated water absorption is a value based on ASTM D570, and specifically, a value obtained by measuring the water absorption when a sample is immersed in water at 23 ° C. for 1 week.

  Examples of the material for forming the core 30 include (meth) acrylic acid esters (fluorine-free (meth) acrylic acid ester (a), fluorine-containing (meth) acrylic acid ester (b)), styrene compounds ( c), vinyl esters (d), main chain cyclic fluorinated polymer forming monomers (e), bisphenol A which is a raw material of polycarbonates, and the like can be used as a polymerizable compound.

  Moreover, the copolymer which combined and polymerized 2 or more types among said material, and the mixture by various combinations of said homopolymer and a copolymer can also be mentioned as an example. In the case of a copolymer and a blend polymer obtained using a mixture as a raw material, the glass transition point of each copolymer or blend polymer is defined as Tg. And among these, what contains (meth) acrylic acid esters or a fluorine-containing polymer as a component is more preferable when comprising an optical transmission body. Next, the above example will be described in more detail.

  As the above (a) fluorine-free methacrylic acid ester and fluorine-free acrylic acid ester, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, tert-butyl methacrylate, benzyl methacrylate, phenyl methacrylate, methacrylic acid Examples include cyclohexyl, diphenylmethyl methacrylate, tricyclo [5.2,1.02,6] decanyl methacrylate, adamantyl methacrylate, isobornyl methacrylate, norbornyl methacrylate, methyl acrylate, ethyl acrylate, acrylic acid- Examples include tert-butyl and phenyl acrylate.

  (B) As fluorine-containing acrylic ester and fluorine-containing methacrylate ester, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3,3 -Pentafluoropropyl methacrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl methacrylate, 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate, 2,2,3, Examples include 3,4,4-hexafluorobutyl methacrylate.

  Examples of (c) styrene compounds include styrene, α-methylstyrene, chlorostyrene, and bromostyrene. Examples of (d) vinyl esters include vinyl acetate, vinyl benzoate, vinyl phenyl acetate, and vinyl chloroacetate. In addition, (e) main chain cyclic fluorinated polymer-forming monomers include those having a cyclic structure as a monomer, or cyclopolymerization to form a fluorinated polymer having a cyclic structure in an amorphous main chain. A monomer for forming a polymer having an alicyclic ring or a heterocyclic ring in the main chain exemplified in Japanese Patent Application Laid-Open No. 8-334634, and Japanese Patent Application No. 2004-2004 And those exemplified in No. 186199. However, the material which can be used for the core part 30 is not limited to these. The type and composition ratio should be determined so that the refractive index of a polymer composed of a polymerizable compound alone or a copolymer has a predetermined refractive index distribution in the multilayer resin when molded into an optical transmission body. Is preferred.

  In addition, when these polymers contain a hydrogen atom (H), it is preferable that the hydrogen atom is substituted with a deuterium atom (D), thereby reducing transmission loss, particularly in the near infrared region. It is possible to reduce the transmission loss at the wavelength.

  Furthermore, in order to use POF12 for near-infrared light, absorption loss due to the C—H bond constituting the polymer occurs, which is described in Japanese Patent No. 3332922 and Japanese Patent Application Laid-Open No. 2003-192708. By using a polymer in which C—H bond hydrogen atoms are replaced with deuterium atoms or fluorine, the wavelength range causing this transmission loss can be lengthened, and the loss of transmission signal light can be reduced. can do. Examples of such polymers include deuterated polymethyl methacrylate (PMMA-d8), polytrifluoroethyl methacrylate (P3FMA), polyhexafluoroisopropyl 2-fluoroacrylate (HFIP 2-FA), and the like. it can. In addition, in order that the compound used as a raw material does not impair the transparency after polymerization, it is desirable that impurities and foreign substances serving as scattering sources are sufficiently removed before polymerization.

  As will be described later, the polymer forming the core portion 30 and the clad portion 31 preferably has a weight average molecular weight of 1 to 1,000,000, more preferably 3 from the viewpoint that it can be suitably stretched after being extruded into a thread shape. ~ 500,000. The suitability for stretching is also related to the molecular weight distribution (MWD: weight average molecular weight / number average molecular weight). If the MWD is too large, the stretchability is increased when components having an extremely large molecular weight are mixed. May worsen, making stretching impossible. Therefore, a preferable MWD range is 4 or less, and a more preferable range is 3 or less.

  When a polymerizable compound is polymerized to obtain a polymer, a polymerization initiator may be used. As the polymerization initiator, for example, there are various types that generate radicals. For example, benzoyl peroxide (BPO), tert-butylperoxy-2-ethylhexanate (PBO), di-tert-butyl peroxide (PBD), tert-butylperoxyisopropyl carbonate (PBI) ) And peroxide compounds such as n-butyl-4,4-bis (tert-butylperoxy) valerate (PHV). 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylpropane), 2,2′-azobis (2-methylbutane), 2,2′-azobis (2-methylpentane), 2,2′-azobis (2,3-dimethylbutane), 2,2 '-Azobis (2-methylhexane), 2,2'-azobis (2,4-dimethylpentane), 2,2'-azobis (2,3,3-trimethylbutane), 2,2'-azobis (2 , 4,4-trimethylpentane), 3,3′-azobis (3-methylpentane), 3,3′-azobis (3-methylhexane), 3,3′-azobis (3,4-dimethylpentane), 3,3'-azobis 3-ethylpentane), dimethyl-2,2′-azobis (2-methylpropionate), diethyl-2,2′-azobis (2-methylpropionate), di-tert-butyl-2,2 ′ -Azo compounds such as azobis (2-methylpropionate). In addition, a polymerization initiator is not limited to these, Moreover, you may use 2 or more types together.

  In order to keep various physical property values such as mechanical properties and thermophysical properties uniform when used as a polymer, it is preferable to adjust the degree of polymerization. A chain transfer agent can be used to adjust the degree of polymerization. About a chain transfer agent, according to the kind of polymerizable monomer used together, a kind and addition amount can be selected suitably. The chain transfer constant of the chain transfer agent for each monomer can be referred to, for example, Polymer Handbook 3rd Edition (J. BRANDRUP and EH IMMERGUT edition, published by JOHN WILEY & SON). The chain transfer constant can also be obtained by experiment with reference to Takayuki Otsu and Masaaki Kinoshita "Experimental Method for Polymer Synthesis", Kagaku Dojin, published in 1972.

  Examples of the chain transfer agent include alkyl mercaptans (for example, n-butyl mercaptan, n-pentyl mercaptan, n-octyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan), thiophenols (thiophenol, m-bromothio). Phenol, p-bromothiophenol, m-toluenethiol, p-toluenethiol, etc.) are preferably used. In particular, it is preferable to use an alkyl mercaptan such as n-octyl mercaptan, n-lauryl mercaptan, and tert-dodecyl mercaptan. A chain transfer agent in which a hydrogen atom of a C—H bond is substituted with a deuterium atom or a fluorine atom can also be used. Of course, the chain transfer agent is not limited to these, and two or more of these chain transfer agents may be used in combination.

  In addition, other additives can be added to the core part 30, the clad part 31, or a part thereof in a range that does not deteriorate the optical transmission performance. For example, a stabilizer can be added to the core 30 or a part thereof for the purpose of improving weather resistance, durability, and the like. In addition, for the purpose of improving optical transmission performance, a stimulated emission functional compound for optical signal amplification can also be added. By adding the compound, the attenuated signal light can be amplified by the excitation light, and the transmission distance can be improved. For example, it can be used as a fiber amplifier in a part of the optical transmission link. These additives can also be contained in the core part 30, the clad part 31, or a part of them by adding to the various polymerizable compounds as the raw material and then polymerizing.

  As described above, when the POF 12 is a GI-type POF in which the refractive index distribution gradually changes from the center of the diameter toward the outside in the core portion 30, an increase in transmission loss can be suppressed and a wider band can be obtained. Optical communication can be performed, and a POF 12 for high-performance communication can be obtained, which is preferable. In order to develop such a desired high and low refractive index distribution, a plurality of polymers having different refractive indexes may be used, and the core portion 30 may be formed as a copolymer by combining them. A method of adding a dopant to the material for forming the core portion 30 is exemplified.

The dopant is a compound that is non-polymerizable and has a different refractive index from the polymerizable monomer that forms the core portion 30 as described above. Further, in comparison with a polymer produced by the synthesis of monomers as described in Japanese Patent No. 3332922 and Japanese Patent Laid-Open No. 5-173026, the difference from the solubility parameter is 7 (cal / cm ³ ) Within ^1/2 , the difference in refractive index is 0.001 or more, and the polymer containing this has the property that the refractive index changes compared to the additive-free polymer. As long as it is stable under the polymerization conditions (such as heating and pressurization) of the polymerizable monomer that forms each of the above members, and can be used without any particular limitation. .

  In addition, when adding a dopant only to the core part 30, it is preferable that the addition rate shall be 0.01-25 weight% with respect to the polymer used as the main component of the core part 30, and 1-20 weight% More preferably. This makes it easier to control the refractive index distribution coefficient in the radial direction of the circular cross section within the preferred range as described above. The dopant concentration is gradually increased toward the center in the radial direction.

  The dopant is preferably a low molecular compound having a high refractive index, a large molecular volume, and a predetermined diffusion rate in the molten resin without participating in polymerization. In this embodiment, after adding such a dopant to the material for forming the core part 30, the progress of polymerization is controlled by the interfacial gel polymerization method, and the concentration of the dopant is given a gradient. Based on the concentration distribution, the refractive index in the radial direction of the core portion 30 is changed. The dopant may be a polymerizable compound, but when a dopant of the polymerizable compound is used, the copolymer containing this as a copolymerization component has an increased refractive index compared to a polymer not containing this. It is preferable to use those having the property of In addition, a dopant is not limited to a monomer, An oligomer (a dimer, a trimer, etc. are included) may be sufficient.

  Examples of the dopant include benzyl benzoate (BEN), diphenyl sulfide (DPS), triphenyl phosphate (TPP), benzyl-n-butyl phthalate (BBP), diphenyl phthalate (DPP), diphenyl (DP), Examples include diphenylmethane (DPM), tricresyl phosphate (TCP), and diphenyl sulfoxide (DPSO), among which BEN, DPS, TPP, and DPSO are preferable. The dopant may be a polymerizable compound such as tribromophenyl methacrylate. In this case, since the polymerizable monomer and the polymerizable dopant are copolymerized when forming the base material in which the dopant is dispersed, it becomes difficult to control the optical characteristics, but the heat resistance can be improved. The effect is obtained.

  The method for imparting the refractive index distribution to the core 30 is not limited to this embodiment. For example, a method of diffusing a dopant after forming the preform 11 that is a precursor of POF 12 is used. And can be applied to the present invention.

  In addition, other additives can be added to the core part 30 and the clad part 31 as long as the optical transmission performance is not deteriorated. For example, a stabilizer can be added to the core 30 or a part thereof for the purpose of improving weather resistance, durability, and the like. In addition, for the purpose of improving optical transmission performance, a stimulated emission functional compound for optical signal amplification can also be added. By adding such a compound, the attenuated signal light can be amplified by the excitation light, and the transmission distance can be improved. For example, it can be used as a fiber amplifier in a part of the optical transmission link.

  About each addition amount of the polymerization initiator mentioned above, a chain transfer agent, and a dopant, a preferable range can be suitably determined according to the kind etc. of the forming material for cores to be used. In this embodiment, the polymerization initiator is added so that it may become 0.005-0.050 mass% with respect to the polymeric compound for cores, and this addition rate is 0.010-0.020. It is more preferable to set it as mass%. The chain transfer agent is added so as to be 0.10 to 0.40% by mass with respect to the polymerizable compound for the core, and the addition rate is 0.15 to 0.30% by mass. More preferably.

  In the present invention, the method for producing POF 12 is not particularly limited, and a method known as a POF production method can be applied. In this embodiment, a material for forming the inner clad 31b and the core portion 30 is sequentially injected into a cylindrical outer clad 31a formed in advance by melt extrusion molding, and is subjected to rotational gel polymerization to perform a three-layered preform. 11 was produced and then stretched while being melted by heating to form POF 12 having a desired diameter. As in the present embodiment, once the preform 11 that is the precursor of the POF 12 is formed and then the POF 12 is formed, for example, the core part 30 and the clad part 31 are separately formed, and then these members are formed. Examples thereof include a method of forming the preform 11 by combining them, and a method of forming the preform 11 by concentrically melting and extruding the material for forming each member at a time and then stretching the material to form the POF 12. In addition, there is a method in which each material is polymerized by applying energy such as heating after extruding each material by melt extrusion without forming the preform 11 to form POF 12.

  In addition, in order to continuously and stably produce a cord by forming a protective layer on the outer periphery of the POF according to the present invention, it is used for curing a protective layer forming resin, such as before and after a coating device or in a hot tub, in a protective layer forming facility. It is preferable to provide a tension measuring device for measuring the tension of the POF and the cord before and after the device for controlling the conveying tension and speed while referring to the tension obtained by the measurement. Thus, the work can be performed while the POF and the cord are smoothly conveyed without being cut or deformed in the middle. Further, before the protective layer is formed on the outer periphery of the POF, if a foreign matter such as dust is wiped off by blowing air around the outer periphery of the POF, a protective layer free from foreign matters can be formed.

  Moreover, when manufacturing the plastic optical fiber cable 23 (henceforth a cable) by coat | covering the outer periphery using the cord 10 obtained by this invention, the coating form is not specifically limited, Various Various forms can be used. As this coating form, a contact type coating in which the interface between one cord 10 and the coating material or the interface between the outer periphery of the cord 10 in a bundled state and the coating material are all in contact with each other, and the coating material There is a loose type coating that forms a void at the interface between the cord 10 and the cord 10, and these can be selected and used as appropriate. However, for loose type coating, for example, when the coating layer peels off at the connection with the connector, moisture may enter from the gaps at the end face and diffuse in the longitudinal direction. Is preferred. However, in the case of the loose type, since the covering material and the cord 10 are not in close contact with each other, it has an advantage that most of the damage such as stress and heat applied to the cable 23 can be alleviated by the covering layer. Depending on the case, it can be preferably used.

  However, the propagation of moisture from the connector connecting portion with the loose-type coating is prevented by filling a gap-like portion at the interface between the cord 10 and the coating material with a fluid semi-solid or granular material having fluidity. be able to. Furthermore, when other different functions such as heat resistance and improvement of mechanical functions are given to these semi-solids and powders, the cable 23 having a multi-functional coating layer can be manufactured. When performing loose type coating, a layer having voids can be formed by adjusting the position of the extrusion nipple of the crosshead die and adjusting the degree of pressure reduction by the pressure reducing device. The thickness of the void layer may be adjusted by pressurizing / depressurizing the nipple thickness and the void layer. When covering the outer periphery of the cord 10 regardless of the contact type or the loose type, a flame retardant, an ultraviolet absorber, an antioxidant, a light raising agent, a lubricant, etc. are included in the coating material. You may add in the range of conditions which do not affect an optical transmission characteristic.

  Moreover, in order to provide the cable 23 with a plurality of functions, a coating layer serving as a functional layer may be appropriately stacked. Examples of the functional layer other than the flame retardant layer include a barrier layer for suppressing moisture absorption of the POF 12 and a moisture absorbing material layer for removing moisture contained in the POF 12. As a method for applying the moisture absorbing material layer, for example, there is a method of providing a moisture absorbing tape or a moisture absorbing gel in a predetermined coating layer or between coating layers.

  In addition, as other functional layers, a flexible material layer for relaxing stress at the time of flexibility, a foam material layer that functions as a buffer material for buffering external stress, and a reinforcing layer for improving rigidity Etc. Further, as the structural material (covering material) of the cable 23, in addition to the resin, for example, a fiber having a high elastic modulus (so-called tensile fiber) and / or a wire material such as a highly rigid metal wire is included in the thermoplastic resin. Can be mentioned. Use of such a material is preferable because the mechanical strength of the cable 23 can be reinforced.

  In addition, examples of the tensile strength fiber include aramid fiber, polyester fiber, and polyamide fiber. Examples of the metal wire include stainless steel wire, zinc alloy wire, and copper wire. However, the tensile strength fiber and the metal wire that can be applied to the present invention are not limited to these. In addition, a metal tube exterior for protecting the cable 23, an aerial support line, a mechanism for improving workability during wiring, and the like can be incorporated in the outer peripheral portion of the cable 23. The shape of the cable 23 may be, for example, a collective type in which the cords 10 are concentrically arranged, a tape type in which the cords 10 are arranged in a line, or a type in which the cables 23 are collected in a presser roll or a wrap sheath. It is done. In addition, what is necessary is just to select these usage forms suitably according to a use.

  In addition, in this invention, the code | cord | chord 10 which provided the protective layer to which the flame retardant was provided expresses the outstanding flame retardance. This flame retardancy is evaluated by performing a combustion test among flame retardance standards determined by UL (Underwriters Laboratory). Although this combustion test may vary depending on the form of the sample, CMX (combustion test, usually referred to as VW-1 test), CM (vertical tray combustion test), CMR (riser Grades such as test) and CMP (plenum test) are set. In the case of POF, since most of the core material is formed of a combustible material, the cord 10 or the cable 23 having a standard of VW-1 or higher is preferable in order to prevent the spread of fire during a fire.

  Since the cable 23 obtained from the cord 10 of the present invention has a higher tolerance for axial displacement than the conventional product, it can be used even if it is joined by butting with a simple jig. However, more preferably, the optical cable is provided with an optical connector for connection at the end of the optical cable, and the mutual connection parts are securely fixed. As the connector, various commercially available connectors such as PN type, SMA type and SMI type which are generally known can be used. Therefore, the cable 23 of the present invention is suitably used in combination with various light emitting elements, light receiving elements, optical switches, optical isolators, optical integrated circuits, optical signal processing devices including optical components such as optical transmission / reception modules, and the like. At this time, it may be combined with other optical fibers as necessary. Any known technique can be applied as a technique related to them. For example, refer to the basics and actuality of plastic optical fibers (issued by NTS), Nikkei Electronics 2001.1.2.3, pages 110-127, "Optical components are mounted on printed circuit boards. be able to.

  Also, by combining with various technologies described in these documents, in-device wiring in computers and various digital devices, internal wiring in vehicles and ships, optical terminals and digital devices, optical links between digital devices and general households For optical transmission systems suitable for short distances such as high-speed and large-capacity data communications such as indoor and regional optical LANs in buildings, apartment houses, factories, offices, hospitals, schools, etc., and control applications that are not affected by electromagnetic waves It can be used suitably.

  Further, IEICE TRANS. ELECTRON. , VOL. E84-C, No. 3, MARCH 2001, p. 339-344 “High-Uniformity Star Coupler Using Diffused Light Transmission”, Journal of Japan Institute of Electronics Packaging, Vol. 3, No. 6,2000, pages 476 to 480, which are described in “Interconnection by Optical Sheet Bus Technology”, and the arrangement of light emitting elements on the waveguide surface described in Japanese Patent Application Laid-Open No. 2003-152284; , JP-A-2002-90571, JP-A-2001-290055, and the like; JP-A-2001-74971, JP-A-2000-329962, JP-A-2001-74966, JP-A-2001-74968 , JP 2001-318263, JP 2001-31840, etc .; optical branch couplers described in JP 2000-241655, etc .; optical star couplers described in JP 2000-241655, etc .; Optical signals described in Japanese Patent Laid-Open Nos. 2002-101044 and 2001-305395 Optical signal bus system; optical signal processing apparatus described in JP-A No. 2002-23011; optical signal cross-connect system described in JP-A No. 2001-86537; optical described in JP-A No. 2002-26815 Multi-function system described in each publication such as JP 2001-339554 A and JP 2001-339555 A; various optical waveguides, optical splitters, optical couplers, optical multiplexers, optical demultiplexers, etc. By combining with, a more advanced optical transmission system using multiplexed transmission and reception can be constructed.

  In addition to the above optical transmission applications, it can also be used in the fields of illumination (light guide), energy transmission, illumination, lenses, and sensors. As the lens, for example, the present invention can be applied to a convex lens whose refractive index gradually decreases from the center of the diameter toward the outside, and conversely, a concave lens whose refractive index gradually increases from the center of the diameter toward the outside. it can.

  Hereinafter, an example is shown and the effect of the present invention is explained concretely. However, the embodiment relating to the present invention is not limited to the embodiment shown here. Further, the manufacturing conditions and manufacturing method of the preform and POF will be described in detail in the first embodiment, and the description of the second embodiment will be omitted when the second embodiment is the same as the first embodiment. In addition, Example 2 is a comparative example with respect to Example 1.

  In Example 1, the coating apparatus shown in FIG. 4 was used in place of the protective layer forming facility 40 shown in FIG. In FIG. 4, the schematic of the coating device used in Example 1 is shown. The coating device 80 includes a die head 81 that functions as a resin pot in FIG. 3, and a screw-type quantitative supply device 82 and a pressurized container 83 as a stirrer.

  In the pressurized container 83, a cartridge 86 filled with a protective layer forming resin 85 in advance is installed at a predetermined position. An air pressure regulator 87 is connected to the pressurized container 83. Then, in response to a request to send the protective layer forming resin 85 to the die head 81, compressed air is sent from the air pressure regulator 87 to the pressurized container 54. As a result, the pressurized container 83 is pressurized, the cartridge-type slide-type bottom pig 89 is moved downward, and the protective layer forming resin 85 in the cartridge 86 is fed into the screw-type metering supply device 82. The degree of pressurization by the air pressure regulator 87 may be appropriately adjusted so that the viscosity of the protective layer forming resin 85 to be used or a desired extrusion amount can be obtained, and is not particularly limited.

  A screw 82 a whose movement is controlled by a motor 88 is provided inside the screw type quantitative supply device 82. Then, by rotating the screw 82a, the protective layer forming resin 85 is stably fed into the die head 81 as appropriate. As described above, when the protective layer forming resin 85 before being fed into the die head 81 is pushed out by the screw type quantitative supply device 82, the protective layer forming resin 85 can be stably supplied, and the thickness of the protective layer can be easily controlled. Therefore, it is preferable.

  Further, inside the die head 81, the protective layer forming resin 85 supplied from the screw type quantitative supply device 82 is pushed out to the outer periphery of the POF 12 being conveyed. As described above, the protective layer forming resin 85 is applied to the outer periphery of the POF 12 to form a coated POF 60. The shape of the die head 81 is not particularly limited as long as the protective layer forming resin 85 can be applied substantially uniformly on the outer periphery of the application target such as the POF 12.

  A method for manufacturing the POF 12 will be described. As the outer clad 31a, PVDF was used to produce a cylindrical tube having an inner diameter of 18.7 mm and a length of 90 cm by commercially available melt extrusion molding. In this cylindrical tube, 204.1 g of deuterated methyl methacrylate (MMA-d8), which is a radical polymerizable compound from which water was removed to 100 ppm or less by distillation as a raw material for the inner cladding 31b, was polymerized. A mixture of dimethyl 2,2′-azobis (2-methylpropionate) (trade name; V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as an initiator and n-lauryl mercaptan as a chain transfer agent is predetermined. The temperature was adjusted before injection. The addition ratios of dimethyl 2,2'-azobis (2-methylpropionate) and n-lauryl mercaptan to MMA are 0.012 mol% and 0.2 mol%, respectively.

  The cylindrical tube into which the raw material for inner cladding was injected was set in a polymerization vessel inside a rotary polymerization apparatus (not shown) so that its longitudinal direction was horizontal, and this was rotated at 3000 rpm in an atmosphere of 70 ° C. under an atmosphere of 70 ° C. Rotation polymerization was carried out by heating for a period of time. At this time, an ungrounded thermocouple was provided in the vicinity of the rotating polymerization vessel, specifically at a distance of 1 to 2 cm, and the measurement temperature by this thermocouple was regarded as the reaction temperature by the polymerization reaction. And when reaction temperature was measured by this method and the temperature peak by the heat_generation | fever of a polymerization reaction was calculated | required, in Example 1, the exothermic peak of 60.8 degreeC was recognized after progress for about 15 hours from superposition | polymerization start. Thus, the cylindrical layer which consists of PMMA-d8 was formed inside the outer clad 31a, and this layer was used as the inner clad 31b.

  Under normal temperature and normal pressure, a material for forming the core part 30 was injected into the hollow part of the inner cladding 31b. The core portion forming material is 81.7 g of MMA-d8 from which moisture is removed to 100 ppm or less, dimethyl 2,2′-azobis (2-methylpropionate) as a polymerization initiator, and n-lauryl as a chain transfer agent. It is a mixture of mercaptan and diphenyl sulfide (DPS) which is a non-polymerizable compound as a dopant. The addition ratios of dimethyl 2,2′-azobis (2-methylpropionate), n-lauryl mercaptan, and DPS to MMA are 0.04 mol%, 0.2 mol%, and 7 mol%, respectively. It was.

  Next, the clad part 31 into which the core part forming material has been injected is set in the polymerization container in the rotary polymerization apparatus used earlier so that its longitudinal direction is horizontal, and then rotated at a rotation speed of 3000 rpm. Polymerization was carried out by heating in an atmosphere at 70 ° C. for 5 hours. Thereafter, the temperature of the atmosphere was raised to 90 ° C. and heat polymerization was performed for 5 hours, and then the rotation was continued at a rotation speed of 500 rpm, and heat treatment was performed at 120 ° C. for 24 hours to form the core portion 30. In addition, after the core portion 30 was formed, natural cooling was performed while rotating to obtain a GI-type preform 11 having a refractive index that gradually increased from the outside of the diameter toward the center. The preform 11 had a Tg of 90 ° C.

  The preform 11 was stored in a drying apparatus capable of adjusting the internal temperature and humidity. In Example 1, the preform 11 was placed in a desiccator (not shown) whose atmosphere was 23 ° C./5% or less and left to stand for one week. Then, this preform 11 was stretched while being heated by a heat stretching apparatus (not shown) to produce POF 12 having an outer diameter of 320 μm. At this time, POF 12 was wound around a winding roll to form a roll. The POF 12 obtained had a transmission loss of 76 dB / km at a measurement wavelength of 650 nm and a transmission band of 2.2 Gb / s · 100 m.

  A cord 10 was manufactured by forming a protective layer on the outer periphery of the POF 12 obtained by heating and stretching the preform 11. First, the POF 12 was continuously sent from the POF roll set on the POF delivery reel 50 and fed to the die head 81 while being supported by the support roller 52. Then, a one-component low-temperature thermosetting urethane elastomer having a viscosity of 160 Pa · S (manufactured by Sunstar Giken Co., Ltd., “PENGUIN FOAM” RD10336C) is fed into the die head 81 as the protective layer forming resin 85. Then, the coating was applied so that the coating outer diameter was 1.2 mm. At the time of application, a cartridge 86 filled with the elastomer is set in a pressurized container 83 in advance, pressurized to 2 atm by an air pressure regulator 87, and the pressure is adjusted so as to be always constant, while the delivery temperature is adjusted. The protective layer forming resin 85 was fed into the die head 81 at room temperature. The rotational speed of the screw 82a inside the screw type quantitative supply device 82 is a value obtained by measuring the outer diameter of the cord 10 after the protective layer forming resin 85 is cured with a laser type outer diameter measuring machine (not shown). Control was made to be constant.

  While the coated POF 60 coated with the protective layer forming resin 85 was fed into the hot tub 43 and conveyed while being wound by the pulley 62, the resin was cured to form the protective layer 20. At this time, the conveying speed was adjusted so that the coated POF 60 was immersed in the hot water 60 for 5 to 10 seconds, and the temperature adjusting device 63 was adjusted to 80 ° C. while circulating the hot water 60. Then, while being supported by the support roller 65, the cord 10 is fed into the first moisture removing device 70 and the second moisture removing device 71 to sufficiently remove moisture adhering to the outer periphery of the cord 10, and then the cord 10 is wound up. It was wound up with a roll 76. In addition, the tension | tensile_strength at the time of conveying the code | cord | chord 10 from the hot tub 43 is adjusted with the take-up roller 44 so that the tear and deformation | transformation of the code | cord | chord 10 may not occur, and the take-up speed of the code | cord | chord 10 by the take-off roller 44 is 20m. / Min. When the flame resistance of the manufactured cord 10 was tested by UL-1581 among the tests standardized by UL, VW-1 showing excellent flame retardancy was achieved. Moreover, it was 1.8 kWh when the power consumption of the protective layer formation equipment 40 was measured.

  A cord 110 was produced by applying a protective layer forming resin to the outer periphery of the POF produced in Example 1 using the protective layer forming equipment 90 shown in FIG. The protective layer forming facility 90 is a typical facility that is generally used when coating an electric wire, a silica-based optical fiber, or the like, and this facility can also be applied to the present invention. The protective layer forming facility 90 includes a delivery device 91, a dust removing device 92, a coating device 93, a first cooling device 94, a second cooling device 95, a moisture removing device 96, a take-up device 97, and a winding device 98.

  The sending device 91 is provided with a tension control means, and sends the POF 100 to the dust removing device 92 while adjusting the tension from the POF roll 91a attached at a predetermined position. Then, while the POF 100 is transported inside the dust removing device 92, the dust attached to the outer periphery is removed by blowing air.

Inside the coating device 93, a delivery device 101 and a die head 102 in which a protective layer forming resin is stored are arranged. Then, while the desired tension is applied and the POF 100 is conveyed, the protective layer forming resin supplied from the delivery device 101 is applied to the outer periphery of the die head 102. At this time, the tension applied to the POF 100 is preferably as small as possible and preferably 700 N / cm ² or less in order not to cause tearing or deformation, but is limited to this value. It is not something.

  The coated POF 105 is sent to the first cooling water tank 94 and then sent to the second cooling water tank 95. Both the first cooling water tank 94 and the second cooling water tank 95 have water tanks adjusted to a desired water temperature, and the protective layer is formed by immersing the coated POF 105 in these water tanks during transportation. The protective resin is cured to form a protective layer. In addition, although the form which used the water tank was shown as an apparatus to cool, it is not specifically limited, For example, you may blow cooling air directly on the code | cord 105 with a blower.

  After cooling, the cord 110 is blown while being transported inside the moisture removing device 96, so that moisture adhering to the outer periphery is wiped off. Then, after being transported by a take-up roller 97 a disposed inside the take-up device 97, it is taken up by a take-up roll 98 a in the take-up device 98. In addition, an appearance inspection device 120, an outer diameter measuring device 121, and a tension meter 122 are provided between the take-up device 97 and the winding device 98. Then, the appearance inspection device 120 observes the presence or absence of foreign matter (for example, a lump due to aggregation of the protective layer forming resin) adhering to the surface of the cord 110 and the outer diameter measuring device 121 measures the diameter of the cord 10. By determining whether or not the value is a desired value, it is possible to determine whether or not the product is a nonstandard product. Note that it is preferable to perform the work while observing and adjusting the tension sequentially with the tension meter 122, since the work related to the formation of the protective layer can be performed while suppressing the cutting and deformation of the POF 100 and the cord 110.

  In Example 2, first, POF 100 was sequentially sent from the POF roll 91a set at a predetermined position inside the sending device 91 to the dust removing device 92, and foreign matters such as dust adhered to the outer periphery of the POF 100 were removed. Then, when the POF 100 was transported to a predetermined position, the desired amount of PVC was sent from the delivery device 101 to the die head 102 and applied to the outer periphery of the POF 100. At this time, the coating treatment was performed while adjusting the temperature at the time of feeding PVC to 170 ° C. and adjusting the conveyance speed to 20 m / min.

  Next, using the first cooling device 94 and the second cooling device 95 in which the coated POF 105 is adjusted so that the temperature of the cooling water is both 10 ° C., the PVC is cooled and protected while being transported inside. A cord 110 provided with a layer was produced. In Example 2, the coating treatment of the resin for forming the protective layer could be performed, but the transmission loss of the obtained cord 110 was 1000 dB / km or more, the cord 110 was cut in the radial direction, and the cross section was observed. As a result, fusion was observed between the POF 100 and the PVC protective layer. Moreover, as a result of conducting the flame retardance test of the cord 110 manufactured by the same method as in Example 1, V-0 was achieved. In addition, the power consumption of the protective layer formation equipment 90 in Example 2 was 20.7 kWh.

  From the results of Examples 1 and 2, Example 1, to which the present invention is applied, has a predetermined viscosity range as compared with Example 2, and is protected by adding an additive such as a flame retardant that imparts desired properties. Since the protective layer is formed using the layer forming resin, the coating process can be performed at a relatively low temperature, and the curing reaction is accelerated in a relatively low temperature range of (Tg-50) to Tg (° C.). I can see that Therefore, since the cord 10 can be manufactured without the POH 12 being cut off during the coating process or the like and without being deformed or deteriorated by being exposed to high heat, as a result, excellent productivity is achieved. It can be seen that the cord 10 having desired characteristics such as excellent flame retardancy on the outer periphery can be manufactured. In addition, since the protective layer which has a desired characteristic can be formed at once when the application | coating operation | work at low temperature is attained as mentioned above, it will become possible to obtain the small diameter cord 10.

  Regarding the power consumption, the value of the first embodiment is very low at about 1/11 compared to the second embodiment. As a cause of this, in Example 1, since a resin having a predetermined viscosity range was used as the protective layer forming resin 55a, a general coating resin was heated and melted by the extrusion pressure at the time of application and the use of compressed air. In addition, the energy can be significantly reduced for cooling, and the temperature of the coating resin can be lowered, so that the pressure applied to the POF 12 during application can be reduced and the deterioration of the POF 12 due to heating can be suppressed. It is considered possible. In Example 1, although the hot tub 43 was used in the curing process of the protective layer forming resin, it can be considered that one of the causes of low power consumption is that the energy can be reduced. In addition to the above effects, the first embodiment can be expected to reduce the cost of manufacturing the device and reduce the size of the device by simplifying the device.

  As described above, when the present invention is applied to a POF manufacturing method, a protective layer having characteristics such as flame retardancy and the like is obtained without causing the POF to be cut, deformed or deteriorated during the operation, and has low energy. It can be formed on the outer periphery of. Thus, the cord in which the protective layer is provided on the outer periphery of the POF exhibits the functionality of the protective layer and has excellent optical characteristics. Therefore, it turns out that this invention is a manufacturing method of the plastic optical material which can implement | achieve the outstanding productivity and low power consumption.

It is a manufacturing-process figure of the plastic optical fiber cord using this invention. It is sectional drawing in the radial direction of the plastic optical fiber cord of this invention. It is the schematic of the protective layer formation equipment used by this invention. It is the schematic of another form of a coating device. It is the schematic of another form of the equipment for protective layer formation.

Explanation of symbols

10 Plastic Optical Fiber Cord 11 Preform 12 Plastic Optical Fiber Wire (POF)
DESCRIPTION OF SYMBOLS 17 Protective layer formation process 18 Application | coating process 19 Curing process 20 Protective layer 30 Core part 31 Clad part 55a Resin for protective layer formation

Claims (6)

In a method for producing a plastic optical material in which a protective layer is provided on an optical waveguide made of a polymer,
An application step of passing the optical waveguide through a protective layer forming material having a viscosity of 10 to 200 (Pa · S) and applying the protective layer forming material to the outer periphery of the optical waveguide;
When the glass transition temperature of the polymer is Tg,
A method for producing a plastic optical material, comprising: a protective layer forming material curing step of curing the protective layer forming material applied in the applying step at a temperature of (Tg-50) to Tg (° C.).   2. The plastic optical material according to claim 1, wherein in the coating step, a container filled with the protective layer forming resin is pressurized, and the protective layer forming material is extruded to the outer periphery of the optical waveguide by the pressure. Production method.   3. The plastic optical material according to claim 1, wherein the protective layer does not contain any of a chlorine compound, a bromine compound, an antimony compound, a cadmium compound, a lead compound, a chromium compound, a zinc compound, and a tin compound. Production method.   4. When the optical waveguide is composed of a region having a plurality of glass transition temperatures, the lowest glass transition temperature among the glass transition temperatures of the plurality of regions is defined as the Tg. A method for producing a plastic optical material according to any one of the above.   5. The method for producing a plastic optical material according to claim 1, wherein a time T <b> 1 required for curing the protective layer forming material is 1 second or more and 10 minutes or less. 6. The plastic according to claim 1, wherein the optical waveguide is a plastic optical fiber, and an outer diameter of the plastic optical fiber including the protective layer is 1.5 mm or less. Manufacturing method of optical material.

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