JPS63137201A - Manufacture of plastic optical fiber - Google Patents

Abstract

PURPOSE:To prevent a substance which exerts adverse influence upon light guide loss from being mixed by arranging a polymer melting cylinder provided with heating facilities in an extruder field zone, plasticizing an annular polymer in the polymer melting cylinder, and supplying it to an extruder and carrying out extrusion molding. CONSTITUTION:A pellet type core material 3 is supplied from the hopper 2 of the core material extruder 1, plasticized by a screw 4, and passed through a gear pump 5. Then it come together at a die 7 for common extrusion with a sheath material extruded from a sheath material extruder 6 and then a plastic optical fiber consisting of the core part 9 and sheath part 10 is extruded from a nozzle 8. Then >=1 heat melting cylinder 12 is provided in the screw field zone 11 and a polymer 13 for the core material (i.e. lump polymer) obtained by lump polymerization is charged in the melting cylinder 12, heated and plasticized, and pressed and supplied to the screw 4. Thus, the material which exerts adverse influence upon the light guide loss is prevented from being mixed to manufacture the plastic optical fiber with low light guide loss.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a plastic optical fiber with low light guiding loss by extrusion molding.

<Prior art> Optical m-fibers are conventionally manufactured using glass-based materials as a base.
It is widely used as an optical signal transmission medium for measurement control between and within devices, for data transmission, for medical purposes, for decoration, and for image transmission.

However, optical bags and bags made of glass-based materials have the disadvantage that they have poor flammability unless they are made with a thin inner diameter, and they also tend to break easily, have a high specific gravity, and have problems with connectors, etc. Recently, various attempts have been made to make this using sticky dough, due to the fact that it is expensive.
The major characteristics of using plastic are that it is lightweight, and even with a large inner diameter of 1#, it is strong and flammable.
Therefore, it is possible to use optical moulds, such as those using plastics, which have excellent operability, such as a high aperture, a large aperture, and easy connection with the light-emitting/receiving tag.
! A common method for producing A is to use glass as a core component, which has a large refractive index and good light transmittance, and to use a transparent plastic as a core component, which also has a low refractive index. This forms fibers having a core-sheath structure. This method transmits light by emitting all the light at the core-sheath interface.There are two methods for producing optical fibers with a core-sheath structure. This is a method of imparting a core-sheath structure by simultaneously discharging both the core-sheath components in a molten state through a special nozzle, and is called a composite spinning method. The other method is a so-called coating method in which the core component is first formed into a predetermined fiber, and then the core component is dissolved in an appropriate solvent and coated with the core component, and then the solvent is removed to form an optical fiber. Amorphous materials are preferable as plastics with high properties, and polymethyl methacrylate and polystyrene are attracting attention from an industrial perspective. (For example,
-8978 Publication) Among them, a polymer mainly composed of methyl methacrylate is most preferable in terms of transparency.0 <Problems to be solved by the invention> The main cause of light guide loss in plastic optical fibers largely depends on the core material. However, the polymers mainly composed of methyl methacrylate used for the core material of plastic optical fibers are generally manufactured by suspension polymerization, and the worsening of light guide loss that is thought to be caused by suspension polymerization is an important factor. It is considered. In other words, contamination of optical impurities in the water used during suspension polymerization, granulation process when beads obtained by suspension polymerization are made into pellets, and optical impurities during the process of feeding the pellets to the hopper. Contamination with impurities and heat in such processes! The present invention solves this problem, in which the oxidation and decomposition products of the core material caused by 9M are directly carried into the core of the plastic optical fiber, increasing the light guiding loss. The present invention relates to a method of manufacturing a plastic optical fiber with low light guiding loss. That is,
The present invention provides a method for extrusion molding a plastic optical fiber, in which at least one polymer melting tube equipped with heating equipment is disposed in the extruder feed zone, a bulk polymer is plasticized in the polymer melting tube, and the polymer is extruded. The present invention relates to a method of manufacturing a plastic optical fiber with low light guiding loss, which is characterized by supplying the fiber to a machine and extrusion molding.

The features of the method of the present invention will be explained with reference to drawings.0 Figure 1 shows an overall view of a plastic optical fiber extrusion device, in which a pellet-shaped core material (8) is supplied from a hopper (2) of a core material extruder (1). The sheath material, which is plasticized by the screw (4) and passed through the gear pump (5), is extruded from the sheath material extruder (6) and joins the co-extrusion die (7) to the nozzle (8).
A plastic optical fiber consisting of a core (9) and a sheath (10) is extruded from the plastic optical fiber.The present invention provides an extrusion apparatus for plastic optical fibers without using the hopper (2) of the core extruder (1). , the screw feed zone (11) is provided with one or more heat-melting tubes (12), and the core material polymer (12) obtained by bulk polymerization is placed in the heat-melting tubes (
In other words, it is characterized in that it is filled with bulk polymer') (18), heated, plasticized, and then supplied to the screw under pressure.0 Figure 2 shows an example of a heat-melting cylinder. Melting tube (
12), a heater to heat it (18 pressurizing device (1
4) and a gear bonder or pulp (15) that controls the supply amount of the plasticized core material. The shape of the heat-melting cylinder is preferably such that the inner surface of the cylinder does not have a concave portion or a groove-like structure so that the molten resin does not stagnate.

Two or more heat-melting cylinders used in the present invention can be used in parallel. Figure 8 shows one example of this.
2-1, 12-2, 12-8) are installed in parallel, and the pulp (15-1, 15-2, 15-8) at the bottom is passed through the flow pipe (16) to the screw feed zone (11). By switching the 0 valve to be supplied, the core material melted in the #L melting cylinder can be continuously supplied to the screw. Further, the heating melting cylinder used in the present invention has one or more P! at the bottom of the melting cylinder. By installing a core material discharge port, it is possible to continuously feed the core material to the screw while discharging a small amount of the melted resin that has been subjected to excessive heat history in contact with the inner wall of the heating melting cylinder.
In the example shown, two or more discharge ports (17-1゜17-2) are provided on the outer periphery of the lower part of the heated melt M cylinder. Has no control [1.

In addition, the heating melting cylinder of the present invention not only allows the buried polymer to be heated, but also allows the bulk polymerization reaction itself to be carried out inside the cylinder.

Examples of the core material used in the present invention include methyl methacrylate polymers and styrene polymers, with methyl methacrylate polymers being preferred in terms of light guide loss and durability.

Examples of the methyl methacrylate-based polymer used in the present invention include those containing methyl methacrylate monomer as the main component and copolymerized with a small amount of acrylic acid ester monomers such as methyl acrylate, ethyl acrylate, and butyl acrylate, and those that have improved heat resistance. Bornyl methacrylate and fentilme for the purpose! Examples include, but are not limited to, those copolymerized with acrylate. Other important ingredients constituting the present invention include polymers containing at least 20 M of 7-purple. It is. Preferred polymers include 2/polymer resin, thermoplastic 7-polymer rubber, and 7-polymer resin.
9 votes rubber. For example, α-
Fluorine-containing polymers and copolymers made of fluoroalkyl fluoroacrylates, alkyl α-fluoroacrylates, fluoroalkyl methacrylates, 74I-containing olefins, and the like can be mentioned.

α-Fluoroalkyl acrylate polymer, α-
Specifically, the alkyl fluoroacrylate and fluoroalkyl methacrylate polymers include α-fluoroacrylic acid 2 , 2 .

2-trifluoroethyl, α-fluoroacrylate 7L' acid 2#2#8,8-tetrafluoropropyl, and its corresponding fluoroalkyl methacrylate, methyl α-fluoroacrylate, ethyl α-fluoroacrylate, Examples include polymers composed of propyl α-fluoroacrylate and the like.

In addition, examples of the fluorine-containing olefin polymer include vinyligne fluoride-tetophfluoroethylene copolymer, trifluoroethylene-vinylidene fluoride copolymer,
Examples include vinylidene fluoride-tetrafluoroethylene-hexafluoroprobene copolymer. <Effects of the invention> There are no oxidative decomposition products generated, and the contamination and generation of substances that affect light guide loss KM are prevented as much as possible. Therefore, it is possible to provide an excellent optical fiber exhibiting low light guiding loss.

<Examples> Next, the present invention will be explained with reference to Examples, but these are merely illustrative examples, and the present invention is not limited thereto.

Example 1 (1) Purification of monomer The monomer used in the polymerization of the core material polymer was one that had been thoroughly passed through and distilled. All polymerizations were performed in an atmosphere with a cleanliness level of 100. The blemishes formed here were observed using a 0.8 μm filter and bright spot observation using a He-No laser.
Vacuum distillation was carried out through basic alumina (with activity level i) (2 polymerized methyl methacrylate (97%) and methyl acrylate (8fi%) were mixed, inner diameter 80 m, total length 5.
0.0018 m as an initiator.
o7/J lauryl peroxide, 0.02 as chain transfer agent
Dissolved gas was removed by adding mol/11 worylmerkabutane, and polymerization was carried out under reduced pressure. Polymerization is 4
0°C for 50fI, 50'Cff for 20 hours, 60c
The temperature was increased stepwise for 10 hours at 80°C and 5 hours at 80°C.
Finally, it was heat-treated at 120CK for 8 hours (8) Spinning The polymer mainly composed of methyl methacrylate, which was bulk polymerized as described above, was processed into a stainless steel P with an inner diameter of 80 m and a total length of 600 m installed in the feed zone of the extruder screw. ,
The mixture was placed in a melting cylinder (flat 12 in Figure 1 or Figure 2) and heated to melt after reducing the pressure. After melting, a load or pressure (for example, nitrogen pressure) is applied to the extrusion rod (14), and a gear pump is used to supply a constant amount into the extruder cylinder to spin an optical fiber.The sheath material used is methacrylic acid 2.2.8 .8 tetoffluoroglovir polymer. The spinning conditions were a core moisture content of 220℃, a sheath material temperature of 210℃, and an extrusion rate of 2 core materials.
．． OKv'hr, the sheath material was 0.4 Kf/hr, and the light guide loss of the obtained plastic optical fiber is shown in Table 1.09i! Example 2 *A plastic optical fiber was manufactured in the same manner as in Example 1, except that the purified monomer was filled into the heat-melting part of the male side 1 and polymerized. The light guide loss of the obtained optical fiber is shown in Table 1.

Comparative Example 1 A polymer mainly composed of suspension polymerized methyl methacrylate (
Sumipex MHO (manufactured by Sumitomo Chemical Industries) was supplied from the extruder hopper (2 in FIG. 1).

All other extrusion molding was carried out under the same conditions as in Example 1. The light guide losses of the obtained optical fibers were as shown in Table IK. Table 1

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a low light guide loss differential optical fiber extrusion apparatus of the present invention. FIG. 2 is a schematic diagram of a heating melting tube, FIG. 8 is a schematic diagram of a parallel heating melting tube, and FIG. 4 is a schematic diagram of a pressurizing melting tube equipped with a discharge port. 1...Core material extruder 2...Hopper 8...Bellet-like core material 4...Screw 5...Gear pump 6...Sheath material extruder 7...Coextrusion die 7 8. ... Nozzle 9 ... Core section 10 ... Sheath section 11 ... Screw feed zone 12 ... Heat melting tube 13 ... Core material polymer (bulk polymer) 14 ... Pressure device ( Extrusion rod) 15...Gear pump or pulp 16...Flow tube 17...Melting~barrel outlet 18...Heating device Fig. 2 Heating melting section

Claims (1)

[Claims] In a method of extrusion molding a plastic optical fiber, at least one polymer melting tube equipped with heating equipment is disposed in an extruder feed zone, and the bulk polymer is plasticized in the polymer melting tube and fed to the extruder. , a method for producing a plastic optical fiber with low light guiding loss, characterized by carrying out extrusion molding.