JP2006126702A - Continuous extrusion system and continuous manufacturing method of plastic optical member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress generation of foreign matters from a polymer in fusion extrusion, and to obtain a plastic optical member superior in optical characteristics. <P>SOLUTION: The maximum height Ry of the surface roughness is set ≤0.8S, in forming the inner surfaces 15a-17a, 38a-40a, 42a-44a of tubes 15-17 and of the liquid flow passages 38, 39, 43, the pockets 40, 44 and the DPS diffusing section 43 of a three-layer joint extruding die 14. To the three-layer joint extruding die 14, PMMA+DPS 35 that is to be the inner core is supplied through the tubes 15-17, as are PMMA 36 that is to be the outer core and PVDF 37 that is to be a clad. The flow passage of each polymer is superior in smoothness, so that depositing of foreign matters is suppressed. Each polymer is extruded as a raw optical fiber filament 18. By imparting desired drawing to the raw optical fiber filament 18, a plastic optical fiber can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plastic optical member continuous extrusion apparatus and a method for continuously producing a plastic optical member.

  In recent years, with the development of the communication industry, the demand for plastic optical transmission bodies has increased, transmission loss is small, and low cost is required. The plastic optical transmission body has advantages such as easy manufacture and processing and low cost compared to the quartz optical transmission body having the same structure. In particular, the plastic optical transmission body has a disadvantage that the transmission loss is slightly larger than that of the quartz-based optical transmission body because all the materials are made of plastic. However, it has the advantages of having good flexibility, light weight, good workability, and easy manufacture of an optical transmission body having a large diameter compared to a quartz optical transmission body. Further, it has an advantage that it can be manufactured at low cost. Therefore, various studies have been made on optical transmission bodies for short distances where the magnitude of transmission loss is not a problem (see, for example, Patent Document 1).

  The plastic optical transmission body includes a core made of plastic (hereinafter referred to as a core or a core part) and an outer shell made of plastic having a lower refractive index than the core part (hereinafter referred to as a clad or a clad part). As one method for producing a plastic optical transmission body, a method is known in which a pipe-like clad portion (hereinafter referred to as a clad pipe) is formed by a melt extrusion method, and a core portion is formed in the clad pipe. In particular, a refractive index distribution type (graded index type, hereinafter referred to as GI type) plastic optical transmission body including a core portion having a distribution of refractive index from the center toward the outside is used for an optical signal to be transmitted. Since it is possible to increase the bandwidth, it has recently attracted attention as an optical transmission body having a high transmission capacity. In one of the manufacturing methods of such a GI type plastic optical transmission body, a preform (base material) is produced by utilizing an interfacial gel polymerization method. Thereafter, a method is known in which the preform is fed into a heating furnace and heated, melted and stretched (see, for example, Patent Document 2).

Another method for producing POF is a melt continuous extrusion method (see, for example, Patent Documents 3 to 6). In this method, a composite fiber composite spinning method can be applied, and productivity can be increased by increasing the number of cores. Furthermore, it has the advantage that clean fibers can be produced continuously and efficiently. That is, POF can be obtained by simultaneously extruding and stretching the core and the clad. Furthermore, a core, a clad, and an outermost layer (usually functioning as a protective layer) are simultaneously extruded and stretched to perform a plastic optical fiber cord (also referred to as a plastic optical fiber core, hereinafter referred to as an optical fiber cord). ) Can be obtained continuously.
JP-A-61-130904 Japanese Patent No. 3332922 JP 2000-356716 A JP 2003-531394 A Japanese Patent No. 34471015 JP-A-8-334635

  The continuous extrusion manufacturing method of GI-type POF described in Patent Document 3 is a method in which a molten resin layer laminated concentrically including a layer containing a dopant is passed through a diffusion region. In this method, the resin layer may stay in the diffusion region for a long time, and the generation of foreign matters due to resin baking on the inner surface of the diffusion region becomes a problem.

  In the method described in Patent Document 4, after each layer is extruded by a multilayer die, the POF precursor is heated at a temperature not higher than the glass transition temperature Tg of the polymer forming the outermost layer, and the diffusibility of the inner layer of the POF precursor is increased. The additive is thermally diffused to create a GI structure. There is no mention of resin seizure on the inner surface of the die, anti-corrosion measures when using a highly corrosive fluorine-based material as the outermost layer, and resin seizure, and a reduction in transmission loss due to the generation of foreign matter becomes a problem. Patent Document 5 describes a method in which a diffusible polymer coexists and flows concentrically and diffuses within a predetermined time. However, this method does not specifically mention productivity.

  In Patent Document 6, two or more kinds of polymers containing a non-polymerizable compound forming an optical transmission body are caused to flow concentrically in a die to produce a plastic optical transmission body. A production method using a resin having a higher viscosity at the center is described. However, measures against adhesion and generation of foreign matter on the inner surface of the flow path have not been studied, and a reduction in transmission loss due to the occurrence of foreign matter becomes a problem.

  An object of the present invention is to provide a plastic optical member continuous manufacturing apparatus and a plastic optical member continuous manufacturing method capable of preventing a reduction in transmission loss due to the generation of foreign matter and continuously manufacturing a plastic optical member.

  The plastic optical member continuous extrusion apparatus of the present invention comprises an extrusion part, an extrusion die, and a pipe connecting the extrusion part and the extrusion die, and extrudes a polymer forming a core and a clad from the extrusion part, In a plastic optical member continuous extrusion apparatus for obtaining a plastic optical member in which the outer periphery of the core is covered with the clad by an extrusion die, the inner surface of the tube through which the polymer flows and / or the extrusion die is smoothed. The plastic optical member continuous extrusion apparatus of the present invention includes a plurality of paths including an extruding part, an extruding die, and a pipe connecting the extruding part and the extruding die, and the polymer extruded from each of the paths is concentrically formed. In the plastic optical member continuous extrusion apparatus that is laminated and extruded from the extrusion die, the path is disposed concentrically, and at least the inner surface of the path disposed inside is smoothed. The surface roughness Ry of the inner surface is preferably 0.8S or less. The inner surface of the tube or the extrusion die is preferably surface-treated with a fluorine-based material. The inner surface of the tube or the extrusion die is preferably surface-treated with a ceramic material. The inner surface of the tube or the extrusion die is preferably subjected to Ni plating treatment or HCr plating treatment.

  In the method for producing a plastic optical member of the present invention, a polymer that forms a core and a clad is extruded from an extruder, and after passing through a tube, a plastic optical member having an outer periphery of the core covered with the clad is obtained by an extrusion die. In the continuous manufacturing method of a plastic optical member, the tube and / or the extrusion die in which the polymer with a smooth inner surface flows are used. The method for producing a plastic optical member of the present invention includes a plurality of paths including an extruding part, an extruding die, and a tube connecting the extruding part and the extruding die, and the polymers extruded from the respective paths are laminated concentrically. Then, in a continuous manufacturing method of a plastic optical member obtained by extruding from the extrusion die to obtain a plastic optical member whose outer periphery of the core is covered with a clad, a path in which at least the inner side of the path arranged concentrically has a smooth inner surface It is. The inner surface of the tube or the extrusion die is preferably surface-treated with a fluorine-based material. The inner surface of the tube or the extrusion die is preferably surface-treated with a ceramic material. The inner surface of the tube or the extrusion die is preferably subjected to Ni plating treatment or HCr plating treatment.

  The polymer is preferably polymethyl methacrylate. The core is preferably a refractive index distribution type.

  When the plastic optical member continuous extrusion apparatus of the present invention is used, the resin flow on the inner surface of the flow path of the plastic optical member material is smooth and the adhesiveness is low, so that there is a resin defect such as thermal deterioration and seizure due to the retention of the material. A plastic optical member that is hardly generated and can be stably produced even for a long time can be manufactured by extrusion. The plastic optical member, particularly a plastic optical fiber, suppresses deterioration of transmission loss.

  Furthermore, the plastic optical member continuous extrusion apparatus of the present invention facilitates cleaning of the die by the inner surface treatment, and has an effect of shortening the cleaning time.

  Hereinafter, the present invention will be described in detail. The preferred embodiment describes a preferred application example of the present invention, and does not limit the present invention.

(Core part)
As the polymerizable monomer for the raw material of the core part, it is preferable to select a raw material that can be easily bulk-polymerized. Examples of raw materials that are highly light transmissive and easy to bulk polymerize include the following (meth) acrylic acid esters (fluorine-free (meth) acrylic acid ester (a), fluorine-containing (meth) acrylic acid ester (b) ), Styrenic compounds (c), vinyl esters (d), main chain cyclic fluorinated polymer-forming monomers (e), etc., and the core is a homopolymer of these, or two of these monomers It can form from the copolymer which consists of the above, and the mixture of a homopolymer and / or a copolymer. Among these, a composition containing (meth) acrylic acid esters as a polymerizable monomer can be preferably used.

Specific examples of the polymerizable monomer listed above include (a) fluorine-free methacrylic acid ester and fluorine-free acrylic acid ester: methyl methacrylate (MMA), ethyl methacrylate, isopropyl methacrylate, methacrylic acid-tert - butyl, phenyl methacrylate benzyl (BzMA), methacrylate, cyclohexyl methacrylate, diphenylmethyl, tricyclo [5 · 2 · 1 · 0 ^2,6] decanyl methacrylate, adamantyl methacrylate, isobornyl methacrylate, norbornene Nyl methacrylate and the like, and methyl acrylate, ethyl acrylate, tert-butyl acrylate, phenyl acrylate, and the like. In addition, (b) fluorine-containing acrylic acid ester and fluorine-containing methacrylate ester include 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, 3,3,4,4-hexafluorobutyl methacrylate and the like. Further, (c) styrene compounds include styrene, α-methylstyrene, chlorostyrene, bromostyrene, and (d) vinyl esters include vinyl acetate, vinyl benzoate, vinyl phenyl acetate, vinyl chloroacetate. (E) The main chain cyclic fluorinated polymer-forming monomers include a polymer having a cyclic structure as a monomer or forming a fluorinated polymer having a cyclic structure in an amorphous main chain by cyclopolymerization. A monomer that forms 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. 2004-186199. What is illustrated by No. is mentioned. Of course, it is not limited to these. The type and composition ratio of the constituent monomers are selected so that the refractive index of the polymer of the core portion made of a monomer alone or a copolymer is equal to or higher than that of the cladding portion. A particularly preferred polymer is polymethyl methacrylate (PMMA), which is a transparent resin.

  Furthermore, when a plastic optical fiber (hereinafter referred to as POF), which is a kind of optical member to be produced, is used for near-infrared applications, an absorption loss due to the C—H bond constituting the polymer of the core portion occurs. Deuterated polymethyl methacrylate (PMMA-d8), polytrifluoroethyl methacrylate (P3FMA), polyhexafluoroisopropyl 2-fluoroacrylate (HFIP 2-FA) and the like as described in Japanese Patent No. 3333292 Using a polymer in which hydrogen atoms (H) of C—H bonds are substituted with deuterium atoms (D), fluorine (F), etc., to increase the wavelength region that causes this transmission loss. And loss of transmission signal light can be reduced. In addition, in order not to impair the transparency after polymerization of the raw material monomer, it is desirable to sufficiently reduce impurities and foreign substances that become scattering sources before polymerization.

(Clad part)
For the material of the clad part, it is preferable to use a material having a refractive index lower than the refractive index of the core part and having good adhesion to the core part because the light transmitted through the core part is totally reflected at the interface between them. Can do. However, in the case where irregularity of the interface between the core part and the clad part is likely to occur due to selection of the material or it is not preferable in terms of manufacturing suitability, a layer may be further provided between the core part and the clad part. For example, by forming an outer core layer made of a polymer having the same composition as the matrix of the core part at the interface with the core part (that is, the inner wall surface of the hollow tube), the interface state between the core part and the cladding part is corrected. can do. Details of the outer core layer will be described later. Of course, without forming the outer core layer, the cladding part itself can be formed of a polymer having the same composition as the matrix of the core part.

  As the material for the clad part, a material excellent in toughness and heat and heat resistance is preferably used. For example, it preferably comprises a homopolymer or copolymer of a fluorine-containing monomer. As the fluorine-containing monomer, vinylidene fluoride (PVDF) is preferable, and a fluororesin obtained by polymerizing one or more polymerizable monomers containing 10% by mass or more of vinylidene fluoride can be preferably used.

  Moreover, when forming a clad part by shape | molding a polymer with the below-mentioned melt extrusion method, it is necessary for the melt viscosity of a polymer to be suitable. As for the melt viscosity, molecular weight is used as a correlated physical property, and particularly, there is a correlation with the weight average molecular weight. In the present invention, the weight average molecular weight is suitably in the range of 10,000 to 1,000,000, more preferably in the range of 50,000 to 500,000.

  Furthermore, it is preferable to prevent moisture from entering the core as much as possible. For this purpose, a polymer having a low water absorption rate is used as a material (material) for the cladding. That is, it is preferable to produce a clad part using a polymer having a saturated water absorption rate (hereinafter referred to as a water absorption rate) of less than 1.8%. More preferably, the clad portion is formed using less than 1.5% polymer, and more preferably less than 1.0% polymer. Further, it is preferable to use a polymer having the same water absorption rate when the outer core layer is produced. The water absorption rate (%) can be calculated by immersing the test piece in water at 23 ° C. for 1 week according to the ASTM D 570 test method and measuring the water absorption rate at that time.

(Polymerization initiator)
When the core part and / or the clad part are made from a polymer polymerized from a polymerizable monomer, a polymerization initiator is used in the polymerization. As a polymerization initiator, it can select suitably according to the monomer and polymerization method to be used, for example, benzoyl peroxide (BPO), tert- butyl peroxy-2-ethyl hexanate (PBO), di-tert-butyl. Examples thereof include peroxide compounds such as peroxide (PBD), tert-butyl peroxyisopropyl carbonate (PBI), and n-butyl-4,4-bis (tert-butylperoxy) valerate (PHV). In addition, 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′-azobis (2- And azo compounds such as methyl propionate). Of course, the polymerization initiator is not limited to these, and two or more kinds may be used in combination.

(Chain transfer agent)
The polymerizable composition for forming a core part and the polymerizable composition for forming a clad part preferably contain a chain transfer agent. The chain transfer agent is mainly used for adjusting the molecular weight of the polymer. When the polymerizable composition for forming the clad part and the core part contains a chain transfer agent, when the polymer is formed from the polymerizable monomer, the polymerization rate and the degree of polymerization are more controlled by the chain transfer agent. And the molecular weight of the polymer can be adjusted to a desired molecular weight. For example, when the obtained preform is drawn by drawing to make POF, the mechanical properties at the time of drawing can be adjusted to a desired range by adjusting the molecular weight, which contributes to improvement of productivity. .

  About the said 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 (edited by J. BRANDRUP and EH IMMERGUT, published by JOHN WILEY & SON). The chain transfer constant can also be obtained by experiment with reference to Takayuki Otsu and Masato Kinoshita, “Experimental Methods for Polymer Synthesis”, Kagaku Dojin, published in 1972.

  Examples of chain transfer agents include alkyl mercaptans (for example, n-butyl mercaptan, n-pentyl mercaptan, n-octyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan), thiophenols (for example, thiophenol, m- Bromothiophenol, 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 (D) or a fluorine atom (F) 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.

(Refractive index modifier)
It is preferable to add a refractive index adjusting agent to the polymerizable composition for the core part. In some cases, the clad part polymerizable composition may contain a refractive index adjusting agent. By providing a distribution of the concentration of the refractive index adjusting agent, a refractive index distribution type core can be easily produced based on the concentration distribution. Even without using a refractive index adjusting agent, it is possible to introduce a refractive index distribution structure by using two or more polymerizable monomers for forming the core portion and having a distribution of the copolymerization ratio in the core portion. It is preferable to use a refractive index adjusting agent in view of the ease of production and the like as compared with the composition ratio control of copolymerization.

The refractive index adjusting agent is also called a dopant, and is a compound different from the refractive index of the polymerizable monomer used together. The refractive index difference is preferably 0.005 or more. The dopant has the property that the polymer containing it has a higher refractive index than the additive-free polymer. These have a difference in solubility parameter of 7 (cal / cm ^{3) in} comparison with a polymer produced by monomer synthesis as described in Japanese Patent No. 3333292 and Japanese Patent Laid-Open No. 5-173026. ) Within ^1/2 , and the difference in refractive index is 0.001 or more, and the polymer containing this has the property of changing the refractive index as compared to the additive-free polymer. Any of those which can stably coexist and are stable under the polymerization conditions (polymerization conditions such as heating and pressurization) of the polymerizable monomer which is the above-mentioned raw material can be used.

  In this embodiment, a dopant is contained in the polymerizable composition for forming a core part, and in the step of forming the core part, the concentration distribution is controlled by the content in the layer and thermal diffusion, and the concentration of the dopant is given a gradient. A method of forming a refractive index distribution structure based on the concentration distribution of the dopant in the core portion will be exemplified. Thus, the core portion having the refractive index distribution is referred to as a “refractive index distribution type core portion”. By forming the gradient index core part, the obtained optical member becomes a gradient index plastic optical fiber (GI POF) having a wide transmission band.

  Examples of the dopant include benzyl benzoate (BEN), diphenyl sulfide (DPS), triphenyl phosphate (TPP), and phthalic acid as described in Japanese Patent No. 3332922 and JP-A-11-142657. Examples include benzyl-n-butyl (BBP), diphenyl phthalate (DPP), diphenyl (DP), diphenylmethane (DPM), tricresyl phosphate (TCP), diphenyl sulfoxide (DPSO), diphenyl sulfide derivatives, and dithian derivatives. Among them, BEN, DPS, TPP, DPSO, sulfurized diphenyl derivatives, and dithian derivatives are preferable. In addition, compounds obtained by substituting hydrogen atoms present in these compounds with deuterium atoms can also be used for the purpose of improving transparency in a wide wavelength region.

  By adjusting the concentration and distribution of the refractive index adjusting agent, the refractive index of the POF that is the optical member can be changed to a desired value. The addition amount is appropriately selected according to the use and the member to be combined. A plurality of types of refractive index adjusting agents may be added.

(Other additives)
In addition, other additives can be added to the polymerizable composition for producing them in the core part, the clad part, or a part thereof, as long as the optical transmission performance is not deteriorated. For example, a stabilizer can be added to the core portion or a part thereof for the purpose of improving weather resistance, durability, and the like. Further, for the purpose of improving optical transmission performance, a stimulated emission functional compound for optical signal amplification can be added. By adding the stimulated emission functional compound, the attenuated signal light can be amplified by the excitation light, and the transmission distance is improved. For example, it can be used as an optical fiber amplifier in a part of the optical transmission link. . These additives can also be contained in the core part, the clad part, or a part of them by adding to the raw material monomer and then polymerizing.

[Protective layer forming material]
By forming a protective layer on the POF manufactured according to the present invention to form an optical fiber cord, the mechanical strength increases and handling becomes easy. As the protective layer forming material used, a material that does not cause thermal damage (for example, deformation, modification, thermal decomposition, etc.) to the POF is selected. Therefore, it is preferable to use a polymer that can be cured at a glass transition temperature Tg (° C.) or lower and (Tg-50) ° C. or higher of the polymer that forms POF. Further, in order to reduce production cost, it is more preferable to use a molding time (time for curing the material) of 1 second to 10 minutes, preferably 1 second to 5 minutes. When the POF is formed from a plurality of polymers, the glass transition temperature at the lowest temperature among the glass transition temperatures of each polymer is regarded as Tg (° C.). In the case where the glass transition temperature Tg (° C.) is not higher than room temperature (for example, about −40 ° C. for PVDF) such as PVDF, or in the case of a polymer having no glass transition temperature, other phase transition temperatures, for example, The melting point is taken as the reference temperature.

  In addition to general olefin polymers such as polyethylene (PE) and polypropylene (PP), and highly versatile polymers such as vinyl chloride and nylon, specific materials for protective layer formation include: Can be mentioned. Since these have high elasticity, they are also effective from the viewpoint of imparting mechanical properties such as bending. First, rubber which is one form of the polymer can be mentioned. Specifically, isoprene-based rubber (for example, natural rubber, isoprene rubber, etc.), butadiene-based rubber (for example, styrene-butadiene copolymer rubber, butadiene rubber), diene special rubber (for example, nitrile rubber, chloroprene rubber, etc.) ), Olefin rubber (for example, ethylene-propylene rubber, acrylic rubber, butyl rubber, halogenated butyl rubber, etc.), ether rubber, polysulfide rubber, urethane rubber and the like.

  As the material for forming the protective layer, it is possible to use a liquid rubber that exhibits fluidity at room temperature and is cured by heating when the fluidity disappears. Specifically, polydiene-based (for example, basic structure is polyisoprene, polybutadiene, butadiene-acrylonitrile copolymer, polychloroprene, etc.), polyolefin-based (for example, basic structure is polyolefin, polyisobutylene, etc.), polyether-based (for example, , Basic structure is poly (oxypropylene), etc., polysulfide type (eg, basic structure is poly (oxyalkylene disulfide), etc.), polysiloxane type (eg, basic structure is poly (dimethylsiloxane), etc.) Can do.

  Examples of the resin (including the base resin of the masterbatch) used in the present invention include thermoplastic resins such as ethylene, propylene or α-olefin polymers. Examples of these polymers include ethylene homopolymers, ethylene-α-olefin copolymers, and ethylene-propylene copolymers.

  A master batch containing a metal hydrate or phosphorus and nitrogen and a flame retardant material as a colorant is used together with these thermoplastic resins. A masterbatch is a product obtained by mixing a functional additive in a resin at a high concentration and kneading. Since the additive is kneaded with the bulk resin, an inorganic compound that is stable against heat is often selected, and its functionality includes an antistatic conductive material, a flame retardant material, a coloring dye, Pigments, and the like, and is often used particularly when a colorant is used as an additive. Further, in order to disperse at a high concentration when preparing a masterbatch, it may be produced by adding a dispersant or a lubricant or modifying the additive.

  Inorganic fine particles as additives used in the present invention are preferably fine in particle size. In particular, if the innermost layer or the outermost layer in contact with the plastic optical fiber is mixed with coarse particles, it is not preferable because the optical fiber is damaged or the workability deteriorates.

  Although it is not specifically limited as an additive, for example, as a conductive substance, noble metal fine particles such as tin, zinc alloy powder and silver, and as a flame retardant substance, metal water such as magnesium hydroxide and aluminum hydroxide is used. Examples of the coloring pigment include carbon black, titanium oxide, and zirconium oxide. Carbon black is low-cost, and when used as a coating material for optical fibers, it has antistatic properties in addition to coloring, making it difficult to be charged with static electricity. It is particularly preferable because it has many advantages such as being restrained from being returned to the outside of the optical fiber due to bending or the like.

  The concentration of the additive contained in the master batch is in the range of 30.0% by weight or less, preferably in the range of 5% by weight or more and 20.0% by weight or less, more preferably 10.0% by weight or more. It is in the range of 15.0% by weight or less. When there are too few additives, there is no effect as a masterbatch, and when it contains more than 30% by weight, the masterbatch becomes brittle or the dispersibility decreases.

  The concentration of the preferred additive contained in the polymer obtained by mixing the masterbatch and the bulk resin is 0.10 wt% or more and 10.0 wt% or less, more preferably 0.15 wt% or more and 5.0 wt%. % Or less, more preferably 0.20% by weight or more and 3.0% by weight or less. When the amount is less than 0.10% by weight, the additive effect of the additive is not substantially exhibited. When the amount exceeds 10%, the fluidity and toughness of the resin are impaired, and troubles such as resin breakage and outer diameter fluctuation occur during coating. appear.

  Further, the molecular weight (for example, number average molecular weight, weight average molecular weight, etc.), molecular weight distribution, melting point, melt flow rate and the like of the thermoplastic resin and masterbatch used in the present invention are not particularly limited. As for the melt flow rate, the melt flow rate (MFR) obtained by the thermoplastic flow test method (JIS K 7210 1916) is an indicator of the fluidity of the resin. The closer the value of MFR, the more uniform the extrusion.

  If the resin melting temperature of the bulk resin and the master batch are different, the flow in the extrusion device becomes non-uniform (the amount of extrusion with the screw varies), resulting in large fluctuations in discharge, and the outer diameter after coating also varies. End up. Therefore, it is preferable that the temperature difference between the melting point of these resins, the bulk resin melting point Ta (° C.) and the master batch melting point Tb (° C.) is small.

In the present invention, the difference between the melting point Ta (° C.) of the thermoplastic resin and the melting point Tb (° C.) of the master batch is preferably | Ta−Tb | ° C ≦ 25 ° C., more preferably | Ta−Tb | ° C. ≦ 10 ° C., and most preferably | Ta−Tb | ° C. ≦ 5 ° C.
When Ta is higher than Tb by 20 ° C., melting of the thermoplastic resin proceeds, but formation of a protective layer becomes difficult because melting of the masterbatch does not proceed. On the other hand, when the difference is larger than 20 ° C., it is necessary to increase the temperature in order to dissolve the thermoplastic resin or the master batch. In this case, the base resin (base resin) constituting the master batch may be decomposed.

In the present invention, the ratio of the melt flow rate M1 (g / 10 min) of the thermoplastic resin to the melt flow rate M2 (g / 10 min) of the master batch is set to (1/4) ≦ (M2 / M1) ≦ ( 4/1), more preferably (1/2) ≦ (M2 / M1) ≦ (2/1), and most preferably (1 / 1.5) ≦ (M2 / M1) ≦. (1.5 / 1).
When the ratio is smaller than 1/4 or when the ratio is larger than 4/1, the coating material has poor compatibility between the thermoplastic resin and the master batch, and it is difficult to form a uniform protective layer. This may cause a problem in dispersion of the additive or lose the flexibility of the protective layer.

In the present invention, the content x (wt%) of the colored fine particles in the coating material is preferably 0.05 ≦ x (wt%) ≦ 20, more preferably 0.07 ≦ x (wt%) ≦ 10. And most preferably 0.1 ≦ x (wt%) ≦ 5.
If it is less than 0.05 wt%, the function of the additive may not be sufficiently exhibited. Moreover, when it exceeds 20 wt%, there exists a possibility that the flexibility of the polymer of a protective layer may be lost.

  As a material for the protective layer, thermoplastic elastomer (TPE) can also be used. Thermoplastic elastomers are a group of substances that exhibit rubber elasticity at room temperature, are plasticized at high temperatures, and are easy to mold. Specific examples include styrene TPE, olefin TPE, vinyl chloride TPE, urethane TPE, ester TPE, amide TPE, and the like. The listed polymers are not particularly limited to the above materials as long as they can be molded at a glass transition temperature Tg (° C.) or less of the POF polymer, particularly the polymer of the core portion. Copolymers and mixed polymers can also be used.

  Moreover, what hardens the liquid which mixed the polymer precursor, the reactive agent, etc. can be used. 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 composed of 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, for the purpose of improving performance, additives such as flame retardants, antioxidants, radical scavengers, lubricants, and various fillers composed of inorganic compounds and / or organic compounds can be added.

  FIG. 1 schematically shows a plastic optical fiber continuous extrusion apparatus (hereinafter referred to as an optical fiber continuous extrusion apparatus) 10 and other apparatuses according to the present invention. The optical fiber continuous extrusion device 10 includes an inner core portion forming material extrusion device 11, an outer core portion formation material extrusion device 12, a cladding portion formation material extrusion device 13, and a three-layer coextrusion die 14. Each extrusion apparatus 11, 12, 13 and the three-layer coextrusion die 14 are connected by pipes 15, 16, and 17. Each material is sent from each of the extrusion apparatuses 11 to 13 to the three-layer coextrusion die 14 through the pipes 15 to 17. Each material is drawn out by a first roller 19 as a fiber (hereinafter referred to as an optical fiber yarn) 18 by a three-layer coextrusion die 14. The drawn optical fiber yarn 18 is conveyed into the water tank 20. Cooling water at 5 ° C. to 30 ° C. is placed in the water tank 20 and the optical fiber yarn 18 is cooled. In the present invention, this cooling step can be omitted.

  An optical fiber is formed by changing the refractive index of the core part and the clad part. In this case, a compound (for example, DPS (diphenyl sulfide), BEN (benzyl benzoate), TPP) that increases the refractive index of the refractive index adjusting agent (dopant) in the core portion forming material or the inner core portion forming material. (Triphenyl phosphate, etc.). Alternatively, a material for reducing the refractive index (for example, a copolymerized fluororesin, a cyclic fluororesin, or the like) is contained in the cladding portion forming material. As a result, a difference in refractive index occurs between the core portion and the clad portion of the optical fiber yarn 18, and the core portion becomes an optical waveguide.

  In the case of a graded index type (GI type) whose center is the highest in the cross section in the cross section and continuously decreases toward the outer periphery (radial direction), a polymerizable monomer (for example, MMA) and a dopant (for example, , DPS) and further an additive such as a polymerization initiator are mixed and fed into the three-layer coextrusion die 14, so that MMA becomes PMMA while polymerizing, and its central portion has the highest refractive index and goes in the radial direction. An optical fiber having a form in which the refractive index continuously decreases can be obtained. Further, instead of the polymerizable monomer, the dopant, and the polymerization initiator, the polymer and the dopant may be fed into the three-layer coextrusion die 14 in a molten state.

  The optical fiber yarn 18 is conveyed through the heating furnace 22 while being drawn by the second roller 19. Although the temperature of the heating furnace 22 is not specifically limited, It is preferable to set it as 120 to 180 degreeC. Further, the optical fiber yarn 18 is further drawn into a plastic optical fiber (hereinafter referred to as an optical fiber) 23 by making the take-up speed of the second roller 21 faster than the take-up speed of the first roller 19. it can. By redrawing the melt-extruded optical fiber yarn 18 in this way, a higher-strength optical fiber 23 can be obtained. Finally, the optical fiber 23 is wound into a roll by a winder 24 and stored as an optical fiber roll 25. By forming a protective layer on the optical fiber roll 25 to obtain a plastic optical fiber cord (plastic optical fiber core wire), an optical transmission body having further improved mechanical strength can be obtained.

  FIG. 2 shows an enlarged view of essential parts such as a three-layer coextrusion die 14 and tubes 15 to 17 used in the present invention. The three-layer coextrusion die 14 includes a core part die 30, a clad part die 31, and a heat insulating plate 32 that insulates them. In addition, temperature controllers 33 and 34 are provided to adjust the temperatures of the dies 30 and 31, respectively. The core part die 30 is connected to the pipe 15 for supplying the inner core part forming material 35 and the pipe 16 for supplying the outer core part forming material 36. Further, a pipe 17 for supplying a clad part forming material 37 is connected to the clad part die 31.

  The inner core portion forming material 35 is sent from the tube 15 to the inner core portion forming portion 38 of the core portion die 30 to form a rod-shaped inner core (hereinafter referred to as a rod-shaped inner core portion). The outer core portion forming material 36 is supplied from the tube 16 to the pocket 40 through the liquid flow path 39. The pressure distribution of the outer core portion forming material 36 is relaxed in the pocket 40, and the outer core portion is formed with a substantially uniform thickness on the outer peripheral surface of the rod-shaped inner core portion. The outer core portion forming material 36 is covered from the pocket 40 so as to cover the outer peripheral surface of the rod-shaped inner core, thereby forming the outer core portion. The core part 41 in which the outer core is formed passes through the diffusion part 42 of the core part die 30. While passing through the diffusion part 42, the dopant is diffused to a desired state. Thereby, the core part which has a refractive index profile of a step index type or a graded index type is obtained. The clad forming material 37 is supplied to the pocket 44 through the pipe 17 and the liquid flow path 43. The pressure distribution of the cladding portion forming material 37 is relaxed by the pockets 44, and the thickness becomes substantially uniform when the outer peripheral surface of the core portion 41 is covered. A clad part forming material 37 is coated so as to cover the outer peripheral surface of the core part 41 and is sent out from the three-layer coextrusion die 14 as a plastic optical fiber yarn (hereinafter referred to as an optical fiber yarn) 18.

  In the present invention, the inner core portion forming material 35, the outer core portion forming material 36, the tubes 15 to 17 through which the cladding portion forming material 37 passes, the inner core portion forming portion 38, the liquid in the optical fiber continuous extrusion apparatus 10. The surface roughness Ry of the flow paths 39, 43, the pockets 40, 44, and the inner surfaces 15a, 16a, 17a, 38a, 39a, 43a, 40a, 44a, 42a of the diffusing portion 42 is set to a predetermined value or less. Thereby, the flow of each forming material 35-37 becomes smooth, and adhesion of each forming material 35-37 to inner surface 15a-17a, 38a-40a, 42a-44a is prevented. And defects, such as thermal deterioration of each forming material 35-37 by the retention | staining accompanying adhesion | attachment of each forming material 35-37, and a burning, can be prevented. Therefore, the optical fiber 23 can be produced continuously for a long time, and productivity can be improved. Further, since the bonding of the respective forming materials 35 to 37 is prevented, there is an effect that the cleaning efficiency is improved when the optical fiber continuous extrusion apparatus 10 is cleaned.

  In order to acquire the said effect, it is preferable that the maximum height Ry of the surface roughness of inner surface 15a-17a, 38a-40a, 42a-44a is 0.8S or less. In the present invention, the maximum height Ry of the surface roughness is a value defined in JIS B0601-1994. In particular, the maximum height Ry of the inner surfaces 38a to 40a and 42a to 44a in the three-layer coextrusion die 14 in which the respective forming materials 35 to 37 are heated, melted and flowed is set to 0.8 S or less. This is preferable because no stagnation accompanying the adhesion of 37 occurs. The maximum height Ry is more preferably 0.4S or less, and most preferably 0.1S or less. Further, the inner surfaces 15a to 17a of the tubes 15 to 17 are also preferably set to have a maximum height Ry of 0.8S or less, more preferably 0.4S or less, and most preferably 0.1S or less. is there. The lower limit of the maximum height Ry is most preferably about 0S. However, since the production of such a three-layer coextrusion die 14 and tubes 15 to 17 causes an increase in production cost, the effect of the present invention can be obtained even when 0.4S or more is used.

  In the present invention, the manufacturing method for satisfying the maximum height Ry of the inner surfaces 15a to 17a, 38a to 40a, and 42a to 44a of the tubes 15 to 17 and the three-layer coextrusion die 14 is not particularly limited. Moreover, the inner surface 15a-17a, 38a-40a, 42a-44a is surface-treated with a fluorine-type material, and the method of obtaining the same effect is mentioned. The fluorine-based material is not particularly limited, but PTFE (polytetrafluoroethylene) or the like is preferably used. Further, the surface treatment method using a fluorine-based material is not particularly limited, and examples thereof include an electroless composite nickel plating method and a vapor deposition method.

Moreover, the method of surface-treating inner surface 15a-17a, 38a-40a, 42a-44a with a ceramic type material is also mentioned. The ceramic material is not particularly limited, but Cr ₂ O ₃ (chromium oxide), TiO ₂ (titania), WC-Co, and the like are preferably used. Further, the forming method is not particularly limited, and examples thereof include a thermal spraying method.

  Furthermore, the method of plating the inner surfaces 15a to 17a, 38a to 40a, and 42a to 44a is also mentioned. As the plating treatment, nickel plating treatment (Ni plating treatment), hard chrome plating treatment (HCr plating treatment) or the like is preferably performed. The Ni plating method is not particularly limited, and an electroless plating method can be used. Further, the HCr plating method is not particularly limited.

  FIG. 3 shows a cross-sectional view of 23 of a plastic optical fiber (optical fiber) according to the present invention. The optical fiber 23 includes an inner core 50 and an outer core 51 that serve as light waveguides, and a clad 52 that totally reflects transmission light at its interface with a lower refractive index than the outer core 51. The diameter and thickness of each part are not particularly limited, but when the inner core diameter D1 is 100 μm to 500 μm, the outer core diameter D2 is preferably 200 μm to 700 μm, and the cladding outer diameter D3 is preferably 300 μm to 1000 μm.

  Further, the main component of the cores 50 and 51 is preferably polymethyl methacrylate (PMMA) in order to reduce optical characteristics and manufacturing costs. By reducing the dopant concentration from the center of the inner core 50 in the radial direction, a graded index plastic optical fiber (GI-POF) that is a refractive index distribution type can be obtained. In order to obtain GI-POF, the inner core portion forming material 35 contains a dopant, and is passed through the diffusion portion 42 of the three-layer coextrusion die 14 so that PMMA is used as a matrix and the dopant is arranged in the gap. An optical fiber yarn 18 can be obtained. GI-POF can be obtained by redrawing the optical fiber yarn 18 as it is or as shown in FIG. When the diffusion of the dopant or the like in the diffusion portion 42 is not sufficient, the refractive index distribution can be formed by heating the optical fiber raw yarn 18 offline for a desired time.

  Further, the plastic optical fiber continuous manufacturing apparatus 10 according to the present invention is not limited to the one shown in FIG. For example, a two-layer coextrusion die that continuously extrudes a core and a clad at the same time, or a die that can coextrude more layers can be used. Alternatively, a plastic optical fiber cord (plastic optical fiber core wire) can be obtained by simultaneously melting and extruding the core portion, the clad portion, and the protective layer. In addition, the flat plastic molding obtained by controlling the take-off speed and extruding to a desired diameter and cutting it in the direction perpendicular to the longitudinal direction has a different refractive index between the central part and the outer peripheral part. It can be used as a so-called GRIN lens.

  An optical fiber according to the present invention, an optical fiber core manufactured using the optical fiber, and a system for transmitting an optical signal using an optical fiber cable include various light emitting elements, light receiving elements, optical switches, optical isolators, An optical signal processing device including optical components such as an optical integrated circuit and an optical transceiver module is used. Moreover, you may combine with another optical fiber etc. as needed. Any known technique can be applied as a technique related to them. For example, the basic and actual of plastic optical fiber (published by NTS Corporation), Nikkei Electronics 2001.1.2.3, pp. 110-127 “Printed Wiring You can refer to "This time, optical components are mounted on the board." Combined with various technologies described in the above documents, internal wiring in computers and various digital devices, internal wiring in vehicles and ships, optical terminals and digital devices, optical links between digital devices, general households and housing complexes・ Suitable for optical transmission systems suitable for short distances such as high-speed, large-capacity data communications and control applications that are not affected by electromagnetic waves, including optical LANs in factories, offices, hospitals, schools, etc. Can be used.

  Furthermore, 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 pp. 476 to 480 described in “Interconnection by Optical Sheet Bus Technology”, and JP-A-10-123350, JP-A-2002-90571, JP-A-2001-290055, etc. Optical bus; described in JP-A-2001-74971, JP-A-2000-329962, JP-A-2001-74966, JP-A-2001-74968, JP-A-2001-318263, JP-A-2001-31840, etc. Optical star couplers described in JP 2000-241655 A, etc .; JP 2002-62457 A, JP 2002-101044 A, JP Optical signal transmission apparatus and optical data bus system described in each publication such as 001-305395; Optical signal processing apparatus disclosed in JP-A-2002-23011; Optical signal cross-connect described in JP-A-2001-86537 System; optical transmission system described in JP-A-2002-26815; multi-function system described in JP-A-2001-339554, JP-A-2001-339555, etc .; and various optical waveguides, optical splitters, By combining with an optical coupler, optical multiplexer, optical demultiplexer, etc., a more advanced optical transmission system using multiplexed transmission / reception can be constructed. In addition to the above optical transmission applications, it can also be used in the fields of illumination, energy transmission, illumination, and sensors.

  Hereinafter, the plastic optical fiber continuous manufacturing method according to the present invention will be described more specifically with reference to Experiment 1 to Experiment 7 according to the present invention. The description was made in detail in Experiment 1 and in other experiments, only the points different from Experiment 1 were explained. The following types of materials, their proportions, operations and the like can be appropriately changed without departing from the spirit of the present invention. Accordingly, the scope of the present invention is not limited to the following examples.

<Experiment 1>
A plastic optical fiber continuous extrusion apparatus 10 equipped with three φ16 mm diameter screw extruders (manufactured by Randcastle) 11, 12, 13 was used. The respective materials 35, 36, and 37 were selected so that the inner core 50 was PMMA + DPS (20 wt%), the outer core 51 was PMMA, and the cladding 52 was PVDF. The extrusion temperature was adjusted with temperature controllers 34 and 35 so that the inner core was 210 ° C, the outer core was 240 ° C, and the clad was 230 ° C.
Each material 35-37 was extruded from the three-layer coextrusion die 14 so as to be an optical fiber yarn 18 having an outer diameter of 1 mm. A three-layer coextrusion die 14 having a φ1 mm inner diameter was used. The tube inner surfaces 15a to 17a and the three-layer coextrusion die inner surfaces 38a to 40a and 42a to 44a were all coated with a fluorine material (PTFE).

  The extruded optical fiber yarn 18 was cooled in a water bath 20 at 15 ° C. and taken up at a speed of 5 m / min by a low speed godet roll 19. And it was taken up at a speed of 9 m / min with the high-speed godet roll 21 while heating in the heating furnace 22 at 150 ° C. An optical fiber 23 having a diameter of about φ750 μm was manufactured and wound as an optical fiber roll 25 by a winder 24. The wound optical fiber 23 was heated in a thermostatic chamber at 190 ° C. for 5 minutes and naturally cooled at room temperature to obtain a gradient index plastic optical fiber. Each material 35-37 was extruded continuously for 1 hour, and the optical fiber 23 was manufactured. Transmission loss was measured using the optical fiber 23 after 1 hour as a sample (30 m long). Ten samples were prepared each. The transmission loss of the manufactured optical fiber 23 was measured at a transmission loss per 1 km (dB / km). The average transmission loss of the optical fiber 23 produced in Experiment 1 was 160 dB / km, which was at a level with no practical problem.

<Experiment 2>
In Experiment 2, inner surfaces 15a to 17a, 38a to 40a, and 42a to 44a were formed of chromium molybdenum steel having a surface roughness Ry of 0.4S. The transmission loss of the obtained optical fiber was an average of 170 dB / km, and none exceeded 200 dB / km.

<Experiment 3>
In Experiment 3, the inner surfaces 15a to 17a, 38a to 40a, and 42a to 44a were subjected to ceramic surface treatment (Cr ₂ O ₃ (chromium oxide) spraying). The transmission loss of the obtained optical fiber averaged 170 dB / km, and there were no samples exceeding 200 dB / km.

<Experiment 4>
In Experiment 4, inner surfaces 15a to 17a, 38a to 40a, and 42a to 44a were subjected to Ni plating treatment (electroless plating method). The average transmission loss of the obtained optical fiber was 180 dB / km, and there were no samples exceeding 200 dB / km.

<Experiment 5>
The fiber optic yarn 18 was continuously extruded for 10 hours under the same conditions as in Experiment 1. An optical fiber after 10 hours was used as a sample. The transmission loss of the obtained optical fiber averaged 170 dB / km, and there were no samples exceeding 200 dB / km. From this, it was found that the plastic optical fiber continuous extrusion apparatus according to the present invention and the plastic optical fiber continuous production method using the apparatus are suitable for long-time continuous production.

<Experiment 6>
In Experiment 6 as a comparative example, the inner surfaces 15a to 17a, 38a to 40a, and 42a to 44a were manufactured from a chromium molybdenum steel having a maximum surface roughness height Ry of 1.6S. The average transmission loss of the obtained optical fiber was 170 dB / km, but one out of 10 exceeded 200 dB / km.

<Experiment 7>
The fiber optic yarn was extruded continuously for 10 hours under the same conditions as in Experiment 6, and the optical fiber after 10 hours was used as a sample. The transmission loss of the obtained optical fiber was 190 dB / km on average, and there were 3 out of 10 samples exceeding 200 dB / km.

1 is a schematic view of a plastic optical fiber continuous device according to the present invention. It is a principal part enlarged view of FIG. It is a cross-sectional view of the plastic optical fiber according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plastic optical fiber continuous extrusion apparatus 14 3 layer coextrusion die 15, 16, 17 Tube 23 Optical fiber 30 Core part die 31 Clad part die

Claims (13)

An extrusion section, an extrusion die, and a tube connecting the extrusion section and the extrusion die,
In a plastic optical member continuous extrusion apparatus for extruding a polymer that forms a core and a clad from the extruding portion, and obtaining a plastic optical member in which an outer periphery of the core is covered with the clad by the extrusion die,
A plastic optical member continuous extrusion apparatus characterized by smoothing the inner surface of the tube and / or the extrusion die through which the polymer flows. Provided with a plurality of paths composed of an extrusion part, an extrusion die, and a pipe connecting the extrusion part and the extrusion die,
In the plastic optical member continuous extrusion apparatus in which the polymer extruded from each of the paths is laminated concentrically and extruded from the extrusion die,
A plastic optical member continuous extrusion apparatus characterized in that the path is arranged concentrically, and at least the inner surface of the path arranged inside is smooth.   3. The plastic optical member continuous extrusion apparatus according to claim 1, wherein the inner surface has a surface roughness Ry of 0.8 S or less.   The plastic optical member continuous extrusion apparatus according to any one of claims 1 to 3, wherein the inner surface of the tube or the extrusion die is surface-treated with a fluorine-based material.   The plastic optical member continuous extrusion apparatus according to any one of claims 1 to 3, wherein the inner surface of the tube or the extrusion die is surface-treated with a ceramic material.   The plastic optical member continuous extrusion apparatus according to any one of claims 1 to 3, wherein an inner surface of the tube or the extrusion die is Ni-plated or HCr-plated. In a continuous production method of a plastic optical member, a polymer that forms a core and a clad is extruded from an extruder, and after passing through a tube, an outer periphery of the core is covered with the clad by an extrusion die.
A method for continuously producing a plastic optical member, wherein the tube and / or the extrusion die in which the polymer having a smooth inner surface flows are used. Provided with a plurality of paths composed of an extrusion part, an extrusion die, and a pipe connecting the extrusion part and the extrusion die,
In the continuous manufacturing method of a plastic optical member for obtaining a plastic optical member in which the outer periphery of the core is covered with a clad by laminating polymers extruded from the respective paths concentrically and extruding from the extrusion die,
A method for continuously producing a plastic optical member, wherein at least an inner side of the paths arranged concentrically is a path having a smooth inner surface.   The method for continuously producing a plastic optical member according to claim 7 or 8, wherein the inner surface of the tube or the extrusion die is surface-treated with a fluorine-based material.   The method for continuously producing a plastic optical member according to claim 7 or 8, wherein the inner surface of the tube or the extrusion die is surface-treated with a ceramic material.   The method for continuously producing a plastic optical member according to claim 7 or 8, wherein an inner surface of the tube or the extrusion die is subjected to Ni plating or HCr plating.   The method for continuously producing a plastic optical member according to any one of claims 7 to 11, wherein the polymer is polymethyl methacrylate. The method for continuously producing a plastic optical member according to any one of claims 7 to 12, wherein the core is a refractive index distribution type.

Images