JP5196891B2 - Plastic optical fiber manufacturing apparatus and plastic optical fiber manufacturing method - Google Patents

Description

  The present invention relates to a plastic optical fiber manufacturing apparatus and a plastic optical fiber manufacturing method.

A plastic optical fiber (hereinafter referred to as “POF”) has a shorter transmission distance than a glass optical fiber, but is easy to handle and handle, is inexpensive and lightweight, and can be set to a large diameter. Therefore, it is used in various applications such as lighting, sensors, and communications. In recent years, practical use for in-vehicle applications has progressed, and the production amount of POF is also increasing.
Examples of such POF include those made of a single material and those having a core-sheath structure in which the surface of the core (core) is covered with a sheath (cladding) made of a material different from the core. ing.

As an industrial production process of POF, the following methods are common.
For example, two or more kinds of resins (polymer materials) having different refractive indexes are melted and discharged by a spinning means equipped with a composite nozzle and spun to form a POF having a concentric core-sheath structure. Next, the POF is guided to a stretching means such as a heating type stretching furnace and subjected to thermal stretching for imparting strength. Next, the stretched POF is wound around a bobbin or the like by winding means such as a winder.
In addition, a composite nozzle has been developed that has a spinning head capable of simultaneously spinning a plurality of POFs by continuously discharging molten resin from a plurality of discharge ports, which enables mass production. It has become.

In the POF manufacturing process as described above, POFs may be fused together at the entrance / exit of the drawing furnace due to yarn swaying in the drawing furnace or in the vicinity of the entrance / exit, and yarn droop resulting from tension drop due to drawing heating. The POF may come into contact with the surface of the POF. In particular, when manufacturing a POF having a core-sheath structure, the outermost layer of the clad portion made of the sheath material was easily damaged.
Therefore, for the purpose of suppressing yarn droop and preventing POF fusion and contact, guide members for restricting the travel of the POF are provided at various locations such as downstream of the spinning means and the drawing means and upstream of the winding means. Yes. Further, for the purpose of ensuring the stability of the yarn introduction, rolls for sending the POF to the post-process or taking it from the pre-process are also provided in various places.

However, the more places where guide members and rolls are installed, the greater the chances of contact with the POF. For this reason, mechanical stress is applied to the outermost layer of the clad portion due to the drag force and friction force received by the POF, and there are cases where various kinds of scratches are generated.
Further, the POF immediately after spinning or immediately after stretching is often in a high temperature state, and the higher the temperature of the POF surface when subjected to stress, the more often the damage to the outermost layer of the clad portion becomes more prominent. .
Furthermore, in recent years, there is a tendency to increase the spinning speed in order to cope with an increase in production volume. However, the higher the spinning speed, the higher the probability that the outermost layer of the cladding part will be damaged.
As described above, the outermost layer of the clad portion is easily damaged by contact force such as a drag force and a friction force constantly received by the POF, and there is a problem peculiar to the core-sheath POF.

Therefore, as a method of suppressing damage to POF, in a heating furnace, in order to suppress contact inside and outside the heating furnace, by providing a non-contact type yarn guide that supplies compressed air to the outlet side of the heating furnace, Prevents the POF from coming into contact with the inner wall of the furnace or between the POFs, thereby reducing yarn swinging in the furnace, suppressing yarn drooping, and avoiding fusion between POFs and formation of scratches on the POF surface. A method has been proposed (see, for example, Patent Document 1).
In addition, after heat stretching of the POF, a heat treatment such as an annealing process is performed while maintaining the POF in a constant length state, the sheath material is melted or plasticized, and the sheath material itself is substantially free of specific birefringence. Thus, a method for preventing an increase in transmission loss has been proposed (see, for example, Patent Document 2).
JP-A-6-201270 JP 2001-174660 A

However, the method described in Patent Document 1 is difficult to apply to guide members disposed at locations other than upstream and downstream of the heating furnace, and guides disposed downstream of the spinning means or upstream of the winding means. It was difficult to reduce POF damage due to contact with members.
In addition, although the method described in Patent Document 2 can reduce the influence of contact scratches as an optical property, it has not always been sufficient to essentially suppress damage to POF.

  The present invention has been made in view of the above circumstances, and an object thereof is to realize a plastic optical fiber manufacturing apparatus and a plastic optical fiber manufacturing method in which damage caused by contact with a guide member is suppressed.

  As a result of intensive studies, the present inventors have provided a metal film (composite plating layer) in which fluororesin fine particles are dispersed on the surface of the guide member, so that even if the plastic optical fiber comes into contact with the guide member, it is difficult to be damaged. As a result, the present invention has been completed.

That is, the plastic optical fiber manufacturing apparatus of the present invention includes spinning means for melt spinning molten resin into a core-sheath structure, stretching means for performing a stretching process, and winding means, and restricts the travel of the plastic optical fiber. A plastic optical fiber manufacturing apparatus provided with a guide member for forming a composite plating layer made of a plating solution containing fluororesin fine particles and a nickel-phosphorous alloy is formed on the surface of the guide member.
Moreover, it is preferable that the said plating solution contains 5-40 volume% of polytetrafluoroethylene.
Furthermore, the present invention is particularly suitable when the guide member is provided downstream of the spinning means, downstream of the stretching means, and upstream of the winding means.

  The plastic optical fiber manufacturing method of the present invention includes a spinning process in which a molten resin is melt-spun into a core-sheath structure by a spinning means, a stretching process in which a stretching process is performed by the stretching means, and a winding using a winding means. A plastic optical fiber manufacturing method that regulates the travel of the plastic optical fiber with a guide member, and a composite plating layer made of a plating solution containing fluororesin fine particles and a nickel-phosphorous alloy on the surface of the guide member Is formed.

Furthermore, even when the final spinning speed of the molten resin is 8 m / min or more, the plastic optical fiber is hardly damaged.
The present invention also includes a core portion and a clad portion having a single-layer or multi-layer structure formed concentrically on the outer periphery of the core portion, wherein the core portion is polymethyl methacrylate, or one or more types The outermost layer of the clad portion contains a tetrafluoroethylene unit and has a heat of crystal melting of 59 mJ / in differential scanning calorimetry (DSC). This method is particularly suitable for producing a plastic optical fiber made of a fluorine-containing olefin resin having a mg or less.

  ADVANTAGE OF THE INVENTION According to this invention, the damage which arises by contacting with a guide member can be suppressed, and the manufacturing apparatus of a plastic optical fiber and the manufacturing method of a plastic optical fiber which can obtain a high quality plastic optical fiber are realizable.

The present invention will be described in detail below.
Hereinafter, the plastic optical fiber (POF) manufacturing apparatus of the present invention will be described with reference to FIG.
FIG. 1 is a schematic diagram showing an example of the overall structure of a POF manufacturing apparatus.

The POF manufacturing apparatus 1 in this example includes a spinning means 10 that heats and melts two or more kinds of resins (polymer materials) having different refractive indexes as raw materials to a predetermined temperature, and spins the POF, and the spinning means. 10 includes a stretching means 30 for performing a stretching process on the POF 20 spun by 10 and a winding means 40 for winding the POF 20 stretched by the stretching means.
Further, the POF manufacturing apparatus 1 of the present invention is provided with a guide member 50 that regulates the travel of the POF 20.

The spinning means 10 is basically composed of a composite nozzle that spins POF, but if necessary, for example, a pipe that supplies the molten resin supplied into the spinning means 10 to the composite nozzle or a composite nozzle. In order to prevent the supplied molten resin from solidifying, heating means (not shown) for heating the inside of the composite nozzle, means for controlling the flow rate of the molten resin flowing into the composite nozzle (not shown), and the like are provided.
The composite nozzle is not particularly limited. For example, if a nozzle having a plurality of discharge ports is used, a plurality of POFs can be spun simultaneously and mass production becomes possible.

The stretching means 30 is not particularly limited as long as it can perform a stretching process on the POF 20, but for example, a heating-type stretching furnace 31 is preferably used. In the stretching furnace 31, the POF is stretched while being heated by a heated gas or steam (steam) supplied into the furnace. By subjecting the POF 20 to stretching, the mechanical strength of the POF 20 can be improved, or the diameter of the POF 20 can be adjusted to be constant.
In addition, before and after the stretching furnace 31, a drive-type feeding-side stretching roll 32 and a take-up-side stretching roll 33 are provided. The POF 20 is guided to the drawing furnace 31 by the take-up drawing roll 33. At this time, the take-up speed of the take-up drawing roll 33 is set to a speed equal to or higher than the feed speed of the feed-side drawing roll 32. A drawing process can be performed.

  The winding means 40 is not particularly limited as long as the stretched POF can be wound around a bobbin or the like. For example, as shown in JP-A-1-321259, characteristics due to damage of POF In order to prevent the deterioration, it is preferable that the interval (pitch) between the POFs is narrowed and wound with a tension as low as possible within a range where no collapse occurs. As an apparatus for winding the POF around the bobbin while controlling the tension, an apparatus having a configuration in which the tension of the optical fiber is controlled by a tension roll, a torque motor or the like and the POF is wound while traversing the guide or the bobbin is suitable.

The POF manufacturing apparatus 1 of the present invention is provided with a guide member 50 that regulates the travel of the POF 20. By providing the guide member 50, it is possible to suppress the drooping of the yarn and prevent the POF from being fused and from contacting inside / outside of each means or near the entrance / exit.
As the shape of the guide member 50, any shape such as a fixed type in which the guide is connected to the shaft core, a rotary type using a bearing, and a comb type can be used. Among these, when controlling the yarn introduction direction of the POF 20 immediately after spinning, or when supporting the POF 20 on the outlet side (downstream) of the stretching means 30, heat may be accumulated in the POF 20. It is preferable to use a rotary guide member capable of obtaining Further, when the yarn introduction direction is precisely controlled, it is preferable to use a fixed guide member.

  As the material of the guide member 50, various metal materials such as stainless steel, aluminum alloy, titanium, titanium alloy, iron, copper, magnesium, magnesium alloy, nickel, and nickel alloy can be used. Among these, it is preferable to use an aluminum alloy because it is lightweight and inexpensive.

A composite plating layer made of a plating solution is formed on the surface of the guide member 50 used in the present invention.
As the plating solution, a solution in which fluororesin fine particles are dispersed in a solution using a nickel-phosphorus alloy as a metal matrix is used. Thus, by using the guide member 50 whose surface is plated with the plating solution in which the fluororesin fine particles are dispersed, the slipperiness of the guide member 50 is improved, and the wear of the POF 20 can be suppressed. Therefore, even if the POF 20 comes into contact with the guide member 50, the surface of the POF 20 is hardly damaged.
In the present invention, when a plurality of guide members 50 are provided, it is not necessary that the composite plating layer is formed on the surfaces of all the guide members.

  Specific examples of the plating solution include those in which fluororesin fine particles are dispersed in an aqueous solution in which a metal salt of a nickel-phosphorus alloy is dissolved. Examples of the metal salt of a nickel-phosphorus alloy include Nim made by Uemura Kogyo Co., Ltd. Den series, Schuma series manufactured by Nihon Kanisen, Melplate series manufactured by Meltex, Top Nicolon series manufactured by Okuno Pharmaceutical Co., Ltd., etc.

Fluorine resin fine particles include polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polyvinylidene fluoride, polyfluoride. Vinylidene fluoride / tetrafluoroethylene copolymer, tetrafluoroethylene / ethylene copolymer (ETFE), and the like. Among these, polytetrafluoroethylene is preferable from the viewpoint of excellent self-lubricity.
The particle size of the fluororesin fine particles is not limited, but is preferably 0.05 to 10 μm and more preferably 0.1 to 2 μm from the viewpoint of dispersibility in the plating solution and stability during film formation. .

  The dispersion amount of the fluororesin fine particles is not limited. For example, when polytetrafluoroethylene is used as the fluororesin fine particles, 5 to 40% by volume is preferable in 100% by volume of the plating solution, and 10 to 30% by volume. More preferred is 15 to 25% by volume. When the content is less than 5% by volume, the amount of the fluororesin fine particles in the composite plating layer formed on the surface of the guide member 50 becomes insufficient, and slipperiness tends to decrease. On the other hand, if the content exceeds 40% by volume, the amount of the fluororesin present in the surface layer of the plating film increases, and the surface may be easily worn.

  The plating solution may contain a reducing agent and a buffer as other additives.

  A method for forming the composite plating layer on the surface of the guide member 50 is not particularly limited, and various plating methods such as an electrolytic plating method and an electroless plating method can be used. In order to form a uniform film in a complicated shape such as the guide member 50, the electroless composite plating method is particularly preferable. According to the present invention, by using the above-described plating solution and applying an electroless composite plating method, a composite plating layer in which fluororesin fine particles are co-deposited on the plating film can be easily formed.

  The thickness of the composite plating layer is not particularly limited as long as the sliding property with POF can be secured, but is preferably 1 nm to 100 μm, and more preferably 10 nm to 50 μm. If the thickness of the composite plating layer is within the above range, the function is sufficiently exhibited. If the thickness is less than 1 nm, the effect of slipperiness may not be fully exhibited. On the other hand, when the thickness exceeds 100 μm, the layer becomes too thick and the film tends to be peeled off.

The installation location of the guide member 50 is not particularly limited, but usually, as shown in FIG. 1, the guide member is usually provided downstream of the spinning means 10, downstream of the stretching means 30, and upstream of the winding means 40. .
The guide member 50A provided downstream of the spinning means 10 serves to control the yarn introduction direction of the POF 20 immediately after spinning.
The guide member 50B provided downstream of the stretching means 30 supports the POF 20 together with the guide member 50A, and plays a role of suppressing the POF 20 from coming into contact with the entrance / exit of the stretching means 30.
The guide member 50 </ b> C provided upstream of the winding means 40 plays a role of preventing thread drooping and collapse to the bobbin in order to smoothly wind the POF 20.
As described above, when the guide member 50 is provided at each location, the number of times the POF 20 contacts the guide member 50 increases in proportion to the number of installations, and the POF 20 is easily damaged. However, by using the guide member 50 having the composite plating layer formed on the surface as in the present invention, even if the POF 20 contacts the guide member 50, the surface of the POF 20 is hardly damaged.

  In the present invention, for the purpose of ensuring the stability of the yarn introduction, rolls for feeding the POF to the post-process or taking it from the pre-process (for example, the drive-type feed side draw roll 32 and the take-up side draw roll 33). Etc.), the above-described composite plating layer may be formed on the roll surface as long as the function of the roll is not impaired.

Next, the POF manufacturing method of the present invention will be described using the POF manufacturing apparatus 1 of FIG.
The method for producing POF of the present invention comprises a spinning process in which a molten resin is melt-spun into a core-sheath structure by the spinning means 10, a stretching process in which the POF 20 spun by the stretching means 30 is stretched, and a stretched POF 20 And a winding step of winding the wire by the winding means 40.

Further, in the present invention, the traveling of the POF is regulated using the guide member 50 described above. As a result, the drooping of the POF can be suppressed, and the POF can be prevented from being fused and contacted at the inside / outside of each means or near the entrance / exit.
By using the guide member 50, the guide member 50 and the POF 20 come into contact with each other. However, in the present invention, as the guide member 50, a guide member having a composite plating layer formed on the surface as described above is used. Since it is used, the slipperiness of the surface of the guide member is improved, and even if the guide member and the POF come into contact with each other, the surface of the POF is hardly damaged.

  The installation location of the guide member 50 is not particularly limited. For example, the guide member 50 may be provided downstream of the spinning means 10, downstream of the stretching means 30, and upstream of the winding means 40 as shown in FIG. The effect can be fully demonstrated.

The spinning step is a step of melt spinning the molten resin into a core-sheath structure.
In recent years, the spinning speed of the molten resin tends to increase in order to cope with the increase in production volume. However, as the spinning speed increases, the frictional force when contacting the guide member increases, so the POF is easily damaged. If the final speed of the spinning speed is less than 8 m / min, damage to the POF due to contact with the guide member is unlikely to occur, but if the final speed of the spinning speed is 8 m / min or more, the yarn jump at the guide member is large. Therefore, the POF is easily damaged. However, in the present invention, since the guide member having the composite plating layer formed on the surface as described above is used, the sliding property of the guide member is improved by the self-lubricating effect of the fluororesin fine particles, and the yarn jump is suppressed. Therefore, damage to the POF surface is greatly reduced.
Therefore, according to the present invention, even if the final spinning speed of the molten resin is 8 m / min or more, the POF is hardly damaged.

  The spinning speed is preferably an initial speed of 3 to 35 m / min, more preferably 5 to 20 m / min. On the other hand, the final speed is preferably 8 to 100 m / min, more preferably 8 to 60 m / min. If the spinning speed is within the above range, mass production can be realized while suppressing damage to the POF.

The stretching step is a step of performing a stretching process on the spun POF. By performing the stretching treatment, mechanical strength can be imparted to the POF, or the diameter of the POF can be adjusted to be constant.
The stretching method is not particularly limited, but for example, a method of stretching while heating using a heating type stretching furnace is preferable.
The heating temperature of POF is preferably Tgc-30 ° C. or higher and Tgc or lower (Tgc is a glass transition temperature of a core material (core material) described later). Moreover, you may extend | stretch, using the heating gas and vapor | steam heated to the temperature of this range, blowing these.
Moreover, it is preferable to extend | stretch so that the aperture of POF may be 250-3000 micrometers.

  The winding process is a process of winding the stretched POF. The winding object is not particularly limited, and examples thereof include a bobbin.

Such a POF manufacturing method has a core-sheath structure having a core portion 21 and a single-layer or multi-layer clad portion 22 formed concentrically on the outer periphery of the core portion 21 as shown in FIG. This is particularly suitable when manufacturing POF20 (SI type POF).
As the core material (core material) that forms the core portion 21, a methyl methacrylate (MMA) -based polymer is used in terms of excellent balance between transparency and mechanical strength. Specifically, homopolymers of MMA units (ie, polymethyl methacrylate (PMMA)), copolymers based on MMA units, copolymers based on benzyl methacrylate units, and fluorinated alkyls Examples thereof include a copolymer having a methacrylate unit as a main component. Among these, PMMA or a copolymer mainly containing MMA units is preferable.

  As the copolymer mainly composed of MMA units, copolymers of MMA units and monomers copolymerizable with the MMA units are preferable. Examples of monomers copolymerizable with MMA include methacrylic acid esters such as cyclohexyl methacrylate, isobornyl methacrylate, benzyl methacrylate, phenyl methacrylate, 2-2-2trifluoroethyl methacrylate, and acrylic acid. Acrylic esters such as methyl and ethyl acrylate; for the purpose of improving heat resistance, monomers such as maleimide compounds such as N-cyclohexylmaleimide and N-isopropylmaleimide, α-methylene-β-methyl- Examples include lactone compounds such as γ-butyrolactone. Among these, α-methylene-β-methyl-γ-butyrolactone is preferable.

The refractive index of the core material is preferably 1.48 to 1.60. If the refractive index is less than 1.48, the difference in refractive index from the sheath material (the inner sheath material or the outer sheath material) becomes small, and the loss increase when bent may be increased. On the other hand, if the refractive index exceeds 1.60, the communication band may be reduced due to a decrease in transparency or a difference in refractive index from the sheath material.
Further, the MFR (melt flow rate) of the core material is preferably 1 to 10 g / 10 minutes. If the MFR is less than 1 g / 10 minutes, the material viscosity becomes too high, and the moldability may be significantly reduced. On the other hand, if the MFR exceeds 10 g / 10 min, the flexibility and workability of the POF may be reduced.

On the other hand, the clad portion 22 may have a single layer structure or a multilayer structure.
However, in the present invention, at least the outermost layer of the clad part 22 includes a tetrafluoroethylene (TFE) unit, and the fluorinated olefin resin has a crystal melting heat in differential scanning calorimetry (DSC) of 59 mJ / mg or less. It is a layer. In addition, when the clad part 22 is a single layer, that layer becomes the outermost layer.

When the clad portion 22 has a multilayer structure, for example, as shown in FIG. 2, it is preferable to have a two-layer structure including an inner layer 22a and an outermost layer 22b. The POF 20 in this example has one inner layer, but may have a layer structure of three or more layers including a plurality of inner layers and an outermost layer. If the clad part has a multi-layer structure, the mechanical properties, heat resistance, and impact resistance of POF are excellent.
The inner sheath material (inner clad material) forming the inner layer 22a is not particularly limited as long as it is a resin used as a POF sheath material. For example, a fluorinated methacrylate polymer (fluorinated MA), fluoride Vinylidene polymers, tetrafluoroethylene polymers, and the like can be used. Among these, a fluorinated methacrylate-based polymer is suitable as an inner sheath material because it can easily adjust the refractive index, has good transparency and heat resistance, and is excellent in flexibility and workability.

The refractive index of the inner sheath material is preferably 1.390 to 1.475. If the refractive index is less than 1.390, the transmission band characteristics when used for communication become narrow, making it difficult to use for communication purposes. On the other hand, if the refractive index exceeds 1.475, the transmission band can be widened, but the light quantity when bent is likely to be significant.
Further, the MFR of the inner sheath material is preferably 5 to 40 g / 10 minutes. If the MFR is less than 5 g / 10 minutes, the material viscosity becomes too high, and the moldability may be significantly reduced. On the other hand, if the MFR exceeds 40 g / 10 min, the flexibility and workability of the POF may be reduced.

As the outer sheath material (outer cladding material) that forms the outermost layer 22b, it is preferable to use a fluorinated olefin resin that includes a TFE unit as a constituent unit and has a heat of crystal melting in DSC of 59 mJ / mg or less.
Such a fluorine-containing olefin-based resin is not particularly limited, but is selected from the group consisting of, for example, vinylidene fluoride (VDF) units, hexafluoropropylene (HFP) units, and perfluoro (fluoro) alkyl vinyl ether (FVE) units. A copolymer obtained by copolymerizing one or more units and a TFE unit, a copolymer obtained by copolymerizing a VDF unit, a TFE unit and a hexafluoroacetone unit, an HFP unit, a TFE unit and ethylene Examples thereof include copolymers obtained by copolymerizing units. VDF units, HFP units, and FVE units are suitable as a copolymerization component with TFE units because they are low in cost, have high transparency, and are excellent in heat resistance.

  The heat of crystal melting is the amount of heat generated due to the heat melting of the fluorine-containing olefin resin, and the crystallinity of the resin increases as the amount of heat increases, and the crystallinity of the resin decreases as it decreases. Is done. Therefore, since the transparency of the clad portion 22 tends to increase as the heat of crystal melting decreases, the smaller the heat of crystal melting, the more suitable the fluorine-containing olefin resin. POF using such a resin tends to suppress an increase in transmission loss even when exposed to a high temperature environment for a long time.

In general, among the fluorinated olefin resins suitably used as the outer sheath material, the fluorinated olefin resin having a crystal melting heat depyrification of 59 mJ / mg or less is a fluorinated olefin resin having a crystal melting heat exceeding 59 mJ / mg. Since the crystallinity is low compared to the resin and the outer sheath material itself is highly elastomeric, the stickiness (adhesiveness) tends to increase. Therefore, when spinning at a high speed, friction at the guide member increases, and yarn jumping is likely to occur. If this yarn jump occurs frequently, not only the surface of the POF (outermost layer) is easily damaged, but also when the guide member has a seam, the POF enters the seam, resulting in a fatal scratch or the POF from the guide member. There is a risk of coming off. However, according to the present invention, since the POF is manufactured using the guide member having the composite plating layer formed on the surface, yarn jumping at the guide member can be suppressed, and damage to the POF surface can be reduced.
Therefore, the present invention can exert a remarkable effect when a fluorine-containing olefin resin having a heat of crystal melting of 59 mJ / mg or less is used as the outer sheath material.

The refractive index of the outer sheath material is preferably 1.325 to 1.420. If the refractive index is less than 1.325, the transmission band may be significantly reduced. On the other hand, if the refractive index exceeds 1.420, the amount of light retained when the POF is bent may be reduced.
Further, the MFR of the outer sheath material is preferably 5 to 120 g / 10 minutes. If the MFR is less than 5 g / 10 minutes, the material viscosity becomes too high, and the moldability may be significantly reduced. On the other hand, if MFR exceeds 120 g / 10 min, the flexibility and workability of POF may be reduced.

The POF obtained in this way may be used in a high temperature environment of, for example, about 70 to 105 ° C. or an environment with a large temperature difference, and a pistoning phenomenon may occur. In order to suppress the pistoning phenomenon, in the POF manufacturing method of the present invention, after the stretching step, annealing may be performed in a continuous manner or in a batch manner in a high temperature environment.
The treatment temperature in the annealing treatment is preferably 90 to 120 ° C., and the treatment time is preferably 1 minute to 100 hours.

  The structure of the POF is not limited to the structure (SI type) as shown in FIG. 2, for example, a GI type POF in which the refractive index of the core portion gradually decreases from the center toward the outer periphery, the center The present invention can also be applied to a structure such as a multi-layer type POF in which the refractive index of the core portion decreases stepwise from the outside to a multi-core type POF having a plurality of core portions in one POF. In order to increase the bandwidth of the POF and perform high-speed signal transmission, it is preferable to use a multilayer POF. Note that the outermost layer made of the outer sheath material as described above may be coated on the outer periphery of the GI-type POF or the multilayer-type POF.

As described above, according to the present invention, by using the guide member having the composite plating layer formed on the surface, the sliding property of the surface of the guide member is improved, so that the contact friction between the POF and the guide member is reduced. , Can suppress damage such as physical scratches. Therefore, even if the POF comes into contact with the guide member, the POF surface is hardly damaged and a high-quality POF can be obtained.
In the present invention, since the composite plating layer is formed using a plating solution in which fluororesin fine particles are dispersed, the guide member exhibits excellent slipperiness due to the self-lubricating property of the fluororesin fine particles and damages to the POF. Reduce.

Further, according to the present invention, even when the final spinning speed when spinning POF is as high as 8 m / min or more, damage to POF can be suppressed.
Furthermore, the present invention provides a high quality product that suppresses damage even when producing an easily damaged POF having a core-sheath structure having an outermost layer made of a fluorinated olefin resin having a melting / melting heat release of 59 mJ / mg or less. POF having a core-sheath structure can be obtained.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
About each measuring method in an Example, it implemented by the following method.

<Measurement method>
(Crystal melting heat (ΔH))
A differential scanning calorimeter (DSC) (manufactured by Seiko Instruments Inc., “DSC-220”) was used for the measurement. The sample was heated to 200 ° C. at a rate of temperature increase of 10 ° C./min, held in that state for 5 minutes and melted, and then cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./min. This operation was repeated again, and the heat of crystal melting at this time was determined.

(Refractive index)
A 200 μm-thick film-shaped test piece was formed by a melt press, and the refractive index (n _D 25) of sodium D-line at 25 ° C. was measured using an Abbe refractometer.

(Melt flow rate (MFR))
Based on the Japanese Industrial Standard JIS K 7210A, MFR was measured from the amount of resin discharged for 10 minutes from a nozzle having a diameter of 2 mm and a length of 8 mm at a load of 210 ° C. and 5 kg.

(PoF surface damage observation)
The surface of the POF was observed using a transmission differential interference microscope (manufactured by Nikon Corporation, “XF-NT-16 type”, magnification: 40 times), and visually evaluated according to the following evaluation criteria.
○: No scratches due to rubbing on the surface.
(Triangle | delta): It is a grade which does not become a problem visually when there is some cracks.
X: Many scratches occurred.

<Example 1>
(material)
Core material: Methyl methacrylate (MMA) homopolymer (PMMA), MFR = 2.4, refractive index = 1.492.
Inner sheath material: fluorinated methacrylate polymer (fluorinated MA; 2,2,2-trifluoroethyl methacrylate (3FM) / 1,1,2,2-perfluorodecyl methacrylate (17FM) / MMA / methacrylic acid (MAA) = 31/50/18/1 (mass%) copolymer), MFR = 20, refractive index = 1.417.
Outer sheath material: fluorinated olefin resin (copolymer of VDF / TFE / HFP = 48/43/9 (mass%)), MFR = 45, refractive index = 1.374, heat of crystal fusion = 14 mJ / mg.

(Manufacturing method)
In the heating-type drawing furnace set at 140 ° C., using the POF production apparatus shown in FIG. 1, melting the raw material, melt spinning the raw material at a final spinning speed of 8 m / min using a concentric composite nozzle, Then, a POF 20 having a diameter of 1000 μm, an inner layer 22a thickness of 5 μm, and an outermost layer 22b thickness of 10 μm as shown in FIG. 2 is manufactured and wound around a bobbin. I took it.
In this case, an electroless composite plating method using a plating solution as a guide member 50A downstream of the spinning means 10 in FIG. 1, a guide member 50B downstream of the stretching means 30, and a guide member 50C upstream of the winder means. An aluminum guide having a composite plating layer formed on the surface was used. As the plating solution, polytetrafluoroethylene (PTFE) having a particle size of 0.5 μm is dispersed in an aqueous solution of a nickel-phosphorus alloy (manufactured by Nippon Kanisen Co., Ltd., “Schuma SK100”) so that the amount of dispersion is 20% by volume. The plating solution was used.
The guide member 50A is a fixed guide, and the guide member 50B and the guide member 50C are rotary guides having a ball bearing attached to the shaft core.
Table 1 shows the composition of the raw materials used in Example 1, and Table 2 shows the manufacturing conditions and the results of POF surface damage observation.

<Examples 2 to 4>
Of the POF materials, the composition of the outer sheath material was changed to that shown in Table 1, and the final speed of the spinning speed was changed to the value shown in Table 2 to produce POF in the same manner as in Example 1. .
Table 2 shows the results of damage observation on the POF surface.

<Comparative Examples 1, 3, 4>
As each guide member 50, an aluminum guide having a hard chrome plated surface is used, the composition of the outer sheath material is changed to that shown in Table 1, and the final spinning speed is changed to the value shown in Table 2. Produced POF in the same manner as in Example 1. The hard chrome plating was performed as follows.
A hard chrome plating layer was formed on the surface of the guide by electrolytic plating using a Sargent bath consisting of 250 g / L of chromic acid and 2.5 g / L of sulfuric acid.
Table 2 shows the results of damage observation on the POF surface.

<Comparative example 2>
Example 1 except that an aluminum guide having a nickel plating layer formed on the surface thereof by an electroless composite plating method was used as each guide member 50 using a plating solution in which PTFE was not dispersed. Thus, POF was produced.
Table 2 shows the results of damage observation on the POF surface.

As apparent from Table 2, the POFs obtained in the examples were excellent products with no scratches on the surface.
On the other hand, scratches were observed on the surface of the POF obtained in the comparative example. In particular, many scratches were observed on the surface of the POFs obtained in Comparative Examples 1, 3, and 4, which were defective.

The present invention has an effect of suppressing the occurrence of scratches on the surface of the POF because the sliding property of the guide member provided in the manufacturing apparatus is good. Further, the structure of the manufactured POF is not limited, and it can correspond to the manufacture of POF having various structures such as SI type, GI type, and multi-core type.
In particular, the effect of the present invention is remarkably exhibited when the spinning speed is increased or when the outermost layer of the clad part is formed of a resin having a low value of heat of crystal fusion in the core-sheath POF.
In recent years, with the expansion of POF communication applications, the scope of use of the present invention is extremely wide from an industrial viewpoint in terms of increasing the production efficiency of POF.

It is the schematic which shows an example of the whole structure of the manufacturing apparatus of POF of this invention. It is sectional drawing which shows an example of the structure of POF.

Explanation of symbols

1: Manufacturing apparatus 10: Spinning means 20: POF
21: Core part 22: Clad part 30: Extending means 40: Winding means 50: Guide member

Claims (6)

A plastic optical fiber manufacturing apparatus having a spinning means for melt spinning a molten resin into a core-sheath structure, a drawing means for performing a drawing process, and a winding means, and provided with a guide member for restricting the travel of the plastic optical fiber. There,
An apparatus for manufacturing a plastic optical fiber, wherein a composite plating layer is formed on a surface of the guide member by a plating solution containing fluororesin fine particles and a nickel-phosphorus alloy.   The apparatus for producing a plastic optical fiber according to claim 1, wherein the plating solution contains 5 to 40% by volume of polytetrafluoroethylene.   3. The plastic optical fiber manufacturing apparatus according to claim 1, wherein the guide member is provided downstream of the spinning means, downstream of the drawing means, and upstream of the winding means. It has a spinning process in which a molten resin is melt-spun into a core-sheath structure by a spinning means, a stretching process in which a stretching process is performed by a stretching means, and a winding process using a winding means. In the manufacturing method of the plastic optical fiber that regulates the traveling of the fiber,
A plastic optical fiber manufacturing method, wherein a composite plating layer is formed on a surface of the guide member by a plating solution containing fluororesin fine particles and a nickel-phosphorus alloy.   5. The method for producing a plastic optical fiber according to claim 4, wherein a final spinning speed of the molten resin is 8 m / min or more. The plastic optical fiber has a core part, and a clad part of a single layer or a multilayer structure formed concentrically on the outer periphery of the core part,
The core portion is made of polymethyl methacrylate or a copolymer of one or more types of vinyl monomer units and methyl methacrylate units, and the outermost layer of the clad portion includes tetrafluoroethylene units, and The method for producing a plastic optical fiber according to claim 4 or 5, comprising a fluorine-containing olefin resin having a heat of crystal fusion of 59 mJ / mg or less in differential scanning calorimetry (DSC).

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