Plastic optical fiber and method for manufacturing plastic optical fiber

Abstract

We provide a plastic optical fiber with a core formed from a novel core material. [Solution] A plastic optical fiber 10 in which the resin material of the core 11 is at least one selected from the following group: (I) At least one cured product selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a portion of the silanol groups are capped, and deuterated polysilsesquioxane containing deuterium. (II) A polymer containing a constituent unit (A) represented by the following formula (1). JPEG2026122747000031.jpg56170 (In formula (1), R 1 ~R 3 (Each of these independently represents either hydrogen (H) or deuterium (D).)

Description

Technical Field

[0001] The present disclosure relates to plastic optical fibers and a method for manufacturing plastic optical fibers.

Background Art

[0002] An optical fiber includes a core as a portion for transmitting light, and a region called a clad provided on the outer periphery of the core for confining light in the core.

[0003] Optical fibers include plastic optical fibers (hereinafter referred to as "POF") in which the core is formed of a resin material, and glass optical fibers (hereinafter referred to as "GOF") in which the core is formed of a glass material. POF is more flexible than GOF and has superior bending resistance (i.e., flexibility) and processability compared to GOF. Furthermore, POF is lighter than GOF. Due to these advantages of POF, it is expected to be applied to various uses.

[0004] In POF, the core is formed of a resin material having a high refractive index. For example, in Patent Document 1, polymethyl methacrylate or a copolymer of one or more vinyl monomer units and methyl methacrylate units has been proposed as a resin material for forming the core.

Prior Art Documents

Patent Documents

[0005]

Patent Document ~ 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present disclosure is to provide a new POF including a core formed of a novel core material not proposed as a core material for conventional POF.

Means for Solving the Problems

[0007] The first aspect of the present disclosure is a plastic optical fiber, wherein the plastic optical fiber includes a core as an optical transmission part, the core contains a resin material as a main component, the resin material is at least one selected from the group consisting of the following (I) to (IV), a plastic optical fiber. (I) At least one cured product selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a part of silanol groups is capped, and deuterated polysilsesquioxane containing deuterium. (II) A polymer containing a structural unit (A) represented by the following formula (1). (III) A polymer containing a structural unit (B) represented by the following formula (2). (IV) A polymer containing a structural unit (C) represented by the following formula (3).

Chemical formula

Chemical formula

Chemical formula

[0008] The second aspect of the present disclosure is a method for manufacturing a plastic optical fiber, the manufacturing method is Heating a core material to make the viscosity of the core material within a range suitable for melt spinning, and forming a core from the core material by a melt spinning method, where the core material contains at least one selected from the group consisting of the following (i) to (iv) as a main component, A method for manufacturing a plastic optical fiber. (i) At least one selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a part of silanol groups is capped, and deuterated polysilsesquioxane containing deuterium. (ii) A polymer containing a structural unit (A) represented by the following formula (1). (iii) A polymer containing a structural unit (B) represented by the following formula (2). (iv) A polymer containing a structural unit (C) represented by the following formula (3). [[ID=I4]] [Chemical formula] (In formula (1), R 1 ~R 3 each independently represents hydrogen H or deuterium D.) [Chemical formula] (In formula (2), R 4 ~R 6 each independently represents hydrogen H or deuterium D.) [Chemical formula] (In formula (3), R 7 ~R 9 each independently represents hydrogen H or deuterium D.) [Advantages of the Invention]

[0009] The present disclosure provides a novel POF provided with a core formed of a novel core material. [Brief Description of the Drawings]

[0010] [Figure 1]Figure 1 is a schematic diagram showing an example of a cross-sectional structure of POF according to an embodiment of the present disclosure. [Figure 2] Figure 2 is an explanatory diagram illustrating that some of the terminal silanol groups of polysilsesquioxane are capped by a reaction with hexamethyldisilazane, resulting in modified polysilsesquioxane. [Figure 3] Figure 3 is a flowchart showing a method for manufacturing POF according to an embodiment of the present disclosure. [Figure 4] Figure 4 is a schematic cross-sectional view showing an example of a manufacturing apparatus that can be used to manufacture POF according to the embodiments of this disclosure. [Modes for carrying out the invention]

[0011] The POF according to the embodiments of this disclosure will be described.

[0012] Figure 1 is a schematic diagram showing an example of a cross-sectional structure of POF according to an embodiment of the present disclosure.

[0013] The POF10 according to this embodiment includes a core 11 as an optical transmission section. As shown in Figure 1, the POF10 according to this embodiment may further include a cladding 12 arranged on the outer periphery of the core 11 and a covering layer 13 arranged on the outer periphery of the cladding 12. If the cladding 12 is provided, the covering layer 13 is arranged on the outer periphery of the cladding 12; however, if the cladding 12 is not provided, for example, the covering layer 13 may be arranged on the outer periphery of the core 11, in contact with the core 11.

[0014] Core 11 mainly contains a resin material. Here, the main component in Core 11 refers to the component that is present in the largest mass ratio in Core 11. For example, Core 11 may contain 75% by mass or more of the resin component, 80% by mass or more, or 85% by mass or more.

[0015] The resin material that is the main component of core 11 is at least one selected from the group consisting of (I) to (IV) below.

[0016] (I) At least one cured product selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a portion of the silanol groups are capped, and deuterated polysilsesquioxane containing deuterium. (II) A polymer containing a constituent unit (A) represented by the following formula (1). (III) A polymer containing the constituent unit (B) represented by the following formula (2). (IV) A polymer containing a constituent unit (C) represented by the following formula (3). [ka] (In formula (1), R 1 ~R 3 (Each of these independently represents either hydrogen (H) or deuterium (D).) [ka] (In formula (2), R 4 ~R 6 (Each of these independently represents either hydrogen (H) or deuterium (D).) [ka] (In formula (3), R 7 ~R 9 (Each of these independently represents either hydrogen (H) or deuterium (D).)

[0017] The resin materials described in (I) to (IV) above have sufficient transmittance to light at the communication wavelength used in POF (e.g., 850 nm), thus enabling the realization of a core capable of transmitting light, while also possessing the heat resistance required for a POF core. Therefore, the POF 10 according to this embodiment, which has a core 11 mainly composed of the resin materials described in (I) to (IV) above, is a novel POF with a core formed from a novel core material.

[0018] As described above, the resin material in (I) is at least one cured product selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane, and deuterated polysilsesquioxane.

[0019] Polysilsesquioxane has the chemical formula (RSiO 1.5 ) n This is a compound represented by the formula shown. Here, R represents an alkyl group or a phenyl group, and n is, for example, 1 to 10000. The polysilsesquioxane may contain any of the following: a polysilsesquioxane having a random structure (random-type polysilsesquioxane), a polysilsesquioxane having a ladder structure (ladder-type polysilsesquioxane), or a polysilsesquioxane having a cage structure. In order to reduce refractive index unevenness in core 11, it is preferable that the polysilsesquioxane contains random-type polysilsesquioxane as the main component. Note that a polysilsesquioxane containing random-type polysilsesquioxane as the main component means that the most abundant structure is random-type polysilsesquioxane.

[0020] The cured polysilsesquioxane is formed by crosslinking polysilsesquioxane. The cured polysilsesquioxane may be formed by a condensation reaction or by addition polymerization. To further reduce the coloration of the resulting cured product and achieve high transparency, it is preferable that the cured polysilsesquioxane is formed by a condensation reaction. That is, it is preferable that the polysilsesquioxane used is a condensation-curing type that hardens by a condensation reaction. For example, polysilsesquioxane containing silanol groups (Si-OH) at the terminal groups can be suitably used.

[0021] Modified polysilsesquioxane has the chemical formula (RSiO 1.5 ) nIn the polysilsesquioxane represented by , at least a portion of the terminal silanol groups (Si-OH) is capped. Such a modified polysilsesquioxane can be obtained, for example, by reacting the terminal silanol groups of polysilsesquioxane with a silane compound. Examples of silane compounds that can be used for capping include hexamethyldisilazane ([(CH3)3Si]2)NH), chlorotrimethylsilane ((CH3)3SiCl), and N,O-bis(trimethylsilyl)acetamide (CH3C[=NSi(CH3)3]OSi(CH3)3). By using such a modified polysilsesquioxane, the thermosetting reaction during the production of the core 11 is suppressed from progressing too much, and the pot life can be extended. Therefore, the production of the core 11 when using the resin material of (I) above is made easier. Figure 2 shows that some of the terminal silanol groups of polysilsesquioxane are capped by reaction with hexamethyldisilazane, resulting in modified polysilsesquioxane.

[0022] For the reasons stated above, when the resin material that is the main component of the core 11 is (I) above, it is preferable that the resin material contains a cured product of modified polysilsesquioxane in order to facilitate the manufacture of the core 11.

[0023] Regarding modified polysilsesquioxane, in order to reduce refractive index unevenness in core 11, it is preferable that the modified polysilsesquioxane mainly contains modified polysilsesquioxane having a random structure (random-type modified polysilsesquioxane). Note that modified polysilsesquioxane mainly containing random-type modified polysilsesquioxane means that the most abundant structure in the modified polysilsesquioxane is random-type modified polysilsesquioxane.

[0024] Furthermore, the fact that the polysilsesquioxane contained in core 11 is a modified polysilsesquioxane with capped silanol groups can be confirmed, for example, by detecting the atomic groups used for capping using Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR).

[0025] Regarding the cured product of the modified polysilsesquioxane, it is preferable that it be formed by a condensation reaction, similar to the cured product of polysilsesquioxane, in order to further reduce the coloration of the resulting cured product and achieve high transparency. Therefore, it is preferable that the modified polysilsesquioxane used in the production of core 11 has some of its terminal silanol groups capped and also contains silanol groups as terminal groups.

[0026] Deuterated polysilsesquioxane is a polysilsesquioxane in which at least some of the hydrogen atoms are replaced with deuterium. By using a cured product of such deuterated polysilsesquioxane as the resin material for core 11, the absorption loss at a wavelength of 850 nm due to harmonic absorption of CH stretching vibrations is reduced.

[0027] For the reasons stated above, if the resin material that is the main component of the core 11 is (I) above, for example, the absorption loss at a wavelength of 850 nm is reduced, so it is preferable that the resin material contains a cured product of deuterated polysilsesquioxane.

[0028] Regarding deuterated polysilsesquioxane, in order to reduce refractive index unevenness in core 11, it is preferable that the deuterated polysilsesquioxane mainly contains deuterated polysilsesquioxane having a random structure (random-type modified polysilsesquioxane). Note that deuterated polysilsesquioxane mainly containing random-type deuterated polysilsesquioxane means that the most abundant structure in the deuterated polysilsesquioxane is random-type deuterated polysilsesquioxane.

[0029] In order to further reduce the coloration of the resulting cured product of deuterated polysilsesquioxane and achieve high transparency, it is preferable that the cured product of deuterated polysilsesquioxane be formed by a condensation reaction, similar to the cured product of polysilsesquioxane.

[0030] The resin material of (II) above is a polymer containing the constituent unit (A) represented by the formula (1) above. Preferably, the resin material of (II) above is a polymer having repeating units of constituent unit (A). The degree of polymerization of the repeating units is, for example, 10 to 5000. The resin material of (II) above may be a copolymer further containing other constituent units other than constituent unit (A).

[0031] In the constituent unit (A), R 1 ~R 3 ∫ may represent deuterium D. That is, the polymer containing the constituent unit (A) may be deuterated. This reduces, for example, the absorption loss at a wavelength of 850 nm, which originates from the CH bond.

[0032] The monomers that form the constituent unit (A) by polymerization are pentafluorostyrene represented by the following formula (4), or pentafluorostyrene that has been deuterated so that hydrogen H is replaced with deuterium D. [ka] (In formula (4), R 10 ~R 12 (Each of these independently represents either hydrogen (H) or deuterium (D).)

[0033] The resin material of (III) above is a polymer containing the constituent unit (B) represented by formula (2) above. Preferably, the resin material of (III) above is a polymer having repeating units of constituent unit (B). The degree of polymerization of the repeating units is, for example, 10 to 3000. The resin material of (III) above may be a copolymer further containing other constituent units other than constituent unit (B).

[0034] In the constituent unit (B), R 4 ~R6 ∫ may represent deuterium D. That is, the polymer containing the constituent unit (B) may be deuterated. This makes it possible to reduce the absorption loss at a wavelength of 850 nm that originates from the CH bond.

[0035] The monomers that form the constituent unit (B) by polymerization are 4-vinylbiphenyl represented by the following formula (5), or 4-vinylbiphenyl that has been deuterated so that hydrogen H is replaced with deuterium D. [ka] (In formula (5), R 13 ~R 15 (Each of these independently represents either hydrogen (H) or deuterium (D).)

[0036] The resin material of (IV) above is a polymer containing the constituent unit (C) represented by formula (3) above. Preferably, the resin material of (IV) above is a polymer having repeating units of constituent unit (C). The degree of polymerization of the repeating units is, for example, 10 to 3000. The resin material of (IV) above may be a copolymer further containing other constituent units other than constituent unit (C).

[0037] In the constituent unit (C), R 7 ~R 9 ∫ may represent deuterium D. That is, the polymer containing the constituent unit (C) may be deuterated. This makes it possible to reduce the absorption loss at a wavelength of 850 nm that originates from the CH bond.

[0038] The monomers that form the constituent unit (C) by polymerization are 2-vinylbiphenyl represented by the following formula (6), or 2-vinylbiphenyl that has been deuterated so that hydrogen H is replaced by deuterium D. [ka] (In formula (6), R 16 ~R 18 (Each of these independently represents either hydrogen (H) or deuterium (D).)

[0039] The following provides a more detailed explanation of each component of POF10.

[0040] (Core 11) As described above, the core 11 is the region that transmits light. The core 11 is made of a material with a higher refractive index than the cladding 12. With this configuration, light that enters the core 11 is confined inside the core 11 by the cladding 12 and propagates through the optical fiber 10.

[0041] The resin components that make up core 11 are as described above.

[0042] The core 11 may further contain additives in addition to the resin components described above. These additives may include, for example, refractive index modifiers. That is, the core 11 may be formed from a resin composition containing the resin components and additives such as refractive index modifiers.

[0043] For example, germanium-containing compounds and sulfur-containing compounds can be used as refractive index adjusting agents. That is, the refractive index adjusting agent contained in the core 11 may contain at least one selected from the group consisting of germanium-containing compounds and sulfur-containing compounds. By adding these compounds to the resin component contained as the main component of the core 11, the refractive index of the core 11 can be effectively increased.

[0044] Suitable germanium-containing compounds include, for example, hexamethyldigermanium(IV) and octamethyltrigermanium(IV). Suitable sulfur-containing compounds include, for example, diphenyl sulfoxide and diphenyl sulfide. The refractive index modifier contained in core 11 may include at least one selected from the group consisting of hexamethyldigermanium(IV) and diphenyl sulfoxide.

[0045] For example, if the core 11 mainly contains the resin component described in (I) above, germanium-containing compounds and sulfur-containing compounds can be suitably used as refractive index adjusters. Also, if the core 11 mainly contains the resin components described in (II) to (IV) above, sulfur-containing compounds can be suitably used as refractive index adjusters.

[0046] The content ratio of the refractive index adjusting agent in the core 11 is, for example, 1% by mass or more and 25% by mass or less. By including the refractive index adjusting agent in the core 11 in such a ratio, the refractive index of the core 11 can be effectively increased to a desired range.

[0047] Core 11 may contain additives other than refractive index modifiers.

[0048] The core 11 does not necessarily have a refractive index distribution, but it is preferable that it has a refractive index distribution. That is, the POF 10 according to this embodiment may be a step index (SI) type POF, but it is preferable that it is a refractive index distribution (GI) type POF.

[0049] For example, if the core 11 contains the resin component described in (I) above as its main component, the maximum refractive index of the core 11 for light with a wavelength of 850 nm may be, for example, 1.40 or more and 1.43 or less, and the minimum refractive index of the core 11 for light with a wavelength of 850 nm may be, for example, 1.39 or more and 1.40 or less.

[0050] (Clad 12) In the POF10 according to this embodiment, the cladding 12 has a lower refractive index than the core 11. This configuration allows the cladding 12 to confine light within the core 11. The cladding 12 mainly contains, for example, a resin component. Here, "mainly containing a resin component" means that the resin component is the most abundant component by mass in the cladding 12. The cladding 12 may contain 80% by mass or more of the resin component, 90% by mass or more, or 95% by mass or more. The cladding 12 may consist only of the resin component. In addition to the resin component, the cladding 12 may further contain additives.

[0051] The resin components included in the cladding 12 are not particularly limited, as long as they are composed of resins with high transparency. The resin components (I) to (IV) described above may be used as the resin components included in the cladding 12, or as the resin components that are the main components of the core 11.

[0052] For example, if the core 11 contains the above (I) as the main resin component, the cladding 12 may contain cured silicone as the main component. This lowers the refractive index of the cladding 12, allowing light to be trapped in the core 11.

[0053] (Coating layer 13) The coating layer 13 is positioned on the outer periphery of the core 11 to improve the mechanical strength of the POF 10. In the case of a configuration with a cladding 12, the coating layer 13 is positioned on the outer periphery of the cladding 12. For example, the coating layer 13 can be made of materials and configurations that are used as coating layers in known POFs. Examples of materials for the coating layer 13 include various engineering plastics such as polycarbonate, polyester, cycloolefin polymers, cycloolefin copolymers, polytetrafluoroethylene (PTFE), modified PTFE, and tetrafluoroethylene-perfluoroalkoxyethylene copolymers (PFA), or copolymers and mixtures thereof.

[0054] The coating layer 13 may contain polycarbonate resin as its main component. This can improve the mechanical strength and heat resistance of POF10.

[0055] The thickness of the coating layer 13 is preferably, for example, 50 μm or more and 250 μm or less. A thickness of 50 μm or more of the coating layer 13 allows for sufficient protection of the core 11 and cladding 12, thus enabling the production of a highly reliable POF 10. Furthermore, a thickness of 250 μm or less of the coating layer 13 allows for the production of a highly flexible POF 10.

[0056] (POF manufacturing method) The POF10 of this embodiment is manufactured, for example, using a melt spinning method. That is, an example of the manufacturing method of the POF of this embodiment is shown in Figure 3, The core material is heated to a viscosity range that allows for melt spinning, and a core is formed from the core material by melt spinning (S1). Includes.

[0057] The above core material contains as a main component at least one selected from the group consisting of (i) to (iv) below. (i) at least one selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a portion of the silanol groups are capped, and deuterated polysilsesquioxane containing deuterium. (ii) A polymer containing a constituent unit (A) represented by the following formula (1). (iii) A polymer containing the constituent unit (B) represented by the following formula (2). (iv) A polymer containing the constituent unit (C) represented by the following formula (3). [ka] (In formula (1), R 1 ~R 3 (Each of these independently represents either hydrogen (H) or deuterium (D).) [ka] (In formula (2), R 4 ~R 6 (Each of these independently represents either hydrogen (H) or deuterium (D).) [ka] (In formula (3), R 7 ~R 9 (Each of these independently represents either hydrogen (H) or deuterium (D).)

[0058] The viscosity of the core material during melt spinning is preferably, for example, 100 Pa·s or more and 1000 Pa·s or less. The viscosity of the core material can be adjusted, for example, by the heating temperature of the core material.

[0059] When the core material includes the material described in (i) above, it is preferable that the polysilsesquioxane includes polysilsesquioxane having a random structure, the modified polysilsesquioxane includes modified polysilsesquioxane having a random structure, and the deuterated polysilsesquioxane includes deuterated polysilsesquioxane having a random structure. This makes it possible to produce a core 11 with reduced refractive index unevenness.

[0060] Furthermore, if the core material includes the material described in (i) above, the method for manufacturing POF according to this embodiment is: A linear body formed from a core material by melt spinning is subjected to a hardening treatment with a base. Preferably, it further includes

[0061] When a core is fabricated using the melt spinning method with the material described in (i) above, the viscosity of the material may decrease during the heating process to a predetermined temperature to completely harden the linear body formed from the core material by the melt spinning method, making it impossible to maintain the shape of the linear body. Even in such cases, by performing a hardening treatment with a base on the linear body formed from the core material, the shape of the linear body can be maintained until the linear body is completely hardened and the core is formed. Therefore, a core of the desired dimensions can be fabricated with high precision.

[0062] The hardening treatment with a base may be carried out, for example, by exposing a linear body formed from the core material to ammonia gas.

[0063] Figure 4 is a schematic cross-sectional view showing an example of a manufacturing apparatus that can be used to produce the POF10 shown in Figure 1. Here, we will describe an example of manufacturing GI-type POF.

[0064] The apparatus 1000 shown in Figure 4 comprises a first extruder 101a for extruding a first core material, a second extruder 101b for extruding a second core material, a third extruder 101c for extruding a cladding material, and a fourth extruder 101d for forming a coating layer.

[0065] The first extruder 101a includes a first housing section 102a for housing the first core material 1a, and a first extrusion section 103a for pushing the first core material 1a from the first housing section 102a. The first extruder 101a is further provided with a heating section (not shown) so that the first core material 1a can be melted in the first housing section 102a, and so that the molten first core material 1a can be maintained in a molten state until it is molded. A rod-shaped first core material (preform) 1a is inserted into the first housing section 102a through an opening above the first housing section 102a and melted by heating within the first housing section 102a.

[0066] In the first extruder 101a, the first core material 1a is extruded by gas through the first extrusion section 103a to form the core inner layer 2 from the first housing section 102a. The first core material 1a that has been extruded through the first extrusion section 103a to form the core inner layer 2 then moves vertically downward and is supplied to the first chamber 110.

[0067] The second extruder 101b includes a second housing section 102b for housing the second core material 1b, and a second extrusion section 103b for extruding the second core material 1b housed in the second housing section 102b from the second housing section 102b. The second extruder 101b extrudes the molten second core material so as to cover the outer circumference of the core inner layer 2 formed from the first core material 1a extruded from the first extruder 101a. Specifically, the second core material extruded from the second extruder 101b is supplied to the first chamber 110. Within the first chamber 110, the core inner layer 2 formed from the first core material 1a is covered with the second core material to form a core outer circumference 3 that covers the outer circumference of the core inner layer 2. The laminate 4, formed by the core inner layer 2 and the core outer periphery 3 covering the outer periphery of the core inner layer 2, moves from the first chamber 110 to the diffusion tube 120 located vertically below the first chamber 110. The diffusion tube 120 is equipped with a heater (not shown) for heating the laminate. The diffusion tube 120 diffuses the refractive index adjusting agent and the like contained in the core inner layer 2 of the laminate 4 that passes through the inside of the diffusion tube 120 toward the core outer periphery 3. In other words, the core is ultimately formed by the core inner layer 2 and the core outer periphery 3.

[0068] If the core material is the material described in (i) above, for example, the linear body of the laminate 4 after the refractive index adjusting agent has been diffused to form a refractive index distribution may be subjected to a hardening treatment with a base.

[0069] The third extruder 101c has a third housing section 102c for housing the cladding material 1c, and a third extruder section 103c for pushing the cladding material 1c from the third housing section 102c. The third extruder 101c pushes the molten cladding material 1c so as to cover the outer circumference of the laminate 4 that has passed through the diffusion tube 120. Specifically, the cladding material 1c pushed out from the third extruder 101c is supplied to the second chamber 130. Within the second chamber 130, the cladding material 1c is used to cover the laminate 4 (i.e., the core) to form a cladding material 5 that covers the outer circumference of the core. Hereinafter, the laminate 4 will be referred to as the core 4. The laminate formed by the core 4 and the cladding material 5 moves from the second chamber 130 to the third chamber 140, which is located vertically below the second chamber 130.

[0070] If a thermosetting material such as silicone is used for the cladding material 1c, the cladding material 1c is extruded to cover the outer circumference of the laminate 4, and then the cladding material 1c is thermoset.

[0071] The fourth extruder 101d includes a fourth storage section 102d for containing a resin composition 1d for forming a coating layer, a screw 104 positioned within the fourth storage section 102d, and a hopper 105 connected to the fourth storage section 102d. In the fourth extruder 101d, for example, pelletized resin composition 1d is supplied to the fourth storage section 102d through the hopper 105. The resin composition 1d supplied to the fourth storage section 102d is heated and kneaded by the screw 104, softening it and making it flowable. The softened resin composition 1d is then extruded from the fourth storage section 102d by the screw 104.

[0072] The resin composition 1d extruded from the fourth extruder 101d is supplied to the third chamber 140. Inside the third chamber 140, a coating layer 6 is formed that covers the outer periphery of the cladding 5 by coating the surface of the first laminate formed of the core 4 and cladding 5 with the resin composition 1d.

[0073] The second laminate 7, in which the core 4, cladding 5, and coating layer 6 are stacked concentrically, flows from the third chamber 140 into the internal flow channel through the inlet of the nozzle 150. The second laminate 7 is reduced in diameter as it passes through the internal flow channel and is discharged in a fiber-like manner from the discharge port of the nozzle 150.

[0074] The second laminate 7, discharged in a fibrous form from the nozzle 150, flows into the internal space 161 of the cooling tube 160, is cooled as it passes through the internal space 161, and is discharged out of the cooling tube 160 through the opening. The second laminate 7 discharged from the cooling tube 160 passes between the two rolls 171 and 172 of the nip roll 170, and further passes through the guide rolls 173 to 175 before being wound onto the winding roll 176 as POF 10. A displacement meter 180 may be further provided to measure the outer diameter of the POF 10 in the vicinity of the winding roll 176, for example, between the guide roll 175 and the winding roll 176. [Examples]

[0075] (Example 1) [First core material] As the first core material, modified silsesquioxane, the material described in (i) above, was prepared. The silanol groups of silsesquioxane "SR-13H" manufactured by Konishi Chemical Industry Co., Ltd. were capped with hexamethyldisilazane. Specifically, capping was performed by the following method: 300 parts by mass of acetonitrile were added to 100 parts by mass of silsesquioxane (manufactured by Konishi Chemical Industry Co., Ltd., SR-13H) to dissolve the silsesquioxane and obtain a solution. Next, 12 parts by mass of hexamethyldisilazane were added dropwise to the obtained solution while stirring at room temperature for 1 hour, and the silsesquioxane and hexamethyldisilazane reacted to obtain a reaction solution. The acetonitrile contained in the obtained reaction solution was evaporated using an evaporator, and the reaction solution was dried. This obtained modified silsesquioxane.

[0076] Diphenyl sulfoxide was used as a refractive index modifier.

[0077] The modified polysilsesquioxane prepared by the above method was dissolved in ethyl acetate, a solvent, and mixed with diphenyl sulfoxide, a refractive index modifier. The solution was added dropwise, and the solvent was evaporated under conditions of 100°C to dry the mixture. The rod-shaped resin composition obtained by drying was used as the first core material. The concentration of the refractive index modifier in the first core material was 5% by mass.

[0078] [Second core material] The modified silsesquioxane used as the first core material was used as the second core material.

[0079] [Clad materials] Thermosetting silicone (FER-7061-A / B, manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the cladding material. The refractive index of the cladding material was 1.38 (23°C / 589 nm).

[0080] [Materials for forming a coating layer] Polycarbonate resin (Teijin Corporation, Panlite L-1225LM) was used as the material for forming the coating layer.

[0081] [Production of POF] Using the first core material, second core material, cladding material, and material for forming the coating layer prepared by the method described above, a POF having the same structure as POF10 shown in Figure 1 was produced by melt spinning. In this example, the manufacturing apparatus shown in Figure 4 was used for the production of the POF. The specific manufacturing conditions were as follows.

[0082] The first core material was extruded at 100°C to form the core inner layer. The second core material was extruded at 100°C to cover the outer periphery of the core inner layer formed by the first core material, thereby laminating the outer periphery of the core formed by the second core material onto the outer periphery of the core inner layer formed by the first core material. Next, the cladding material was extruded at 100°C to cover the outer periphery of the laminate of the core inner layer and the core outer periphery, and then the cladding layer was extruded at 250°C to laminate onto the outer periphery of the cladding material, after which it was wound up. After that, the wound POF was exposed to 28 wt% ammonia vapor for 2 days to cure the first and second core materials at room temperature.

[0083] For the POF prepared in Example 1, the core diameter (outer diameter of the core) measured by the method described later was 50 μm, the outer diameter of the cladding was 60 μm, and the outer diameter of the coating layer was 250 μm.

[0084] (Example 2) [First core material] As the first core material, a modified silsesquioxane similar to that in Example 1 was prepared.

[0085] Hexamethyldigermanium(IV) was used as a refractive index modifier.

[0086] Modified polysilsesquioxane was dissolved in ethyl acetate, a solvent, and mixed with hexamethyldigermanium(IV), a refractive index modifier. The solution was added dropwise, and the solvent was evaporated at 100°C to dry the mixture. The rod-shaped resin composition obtained by drying was used as the first core material. The concentration of the refractive index modifier in the first core material was 20% by mass.

[0087] [Second core material] The modified silsesquioxane used as the first core material was used as the second core material.

[0088] [Clad materials] The same cladding material as in Example 1 was used.

[0089] [Materials for forming a coating layer] The same coating layer formation material as in Example 1 was used.

[0090] [Production of POF] POF was prepared using the same method as in Example 1.

[0091] For the POF prepared in Example 2, the core diameter (outer diameter of the core) measured by the method described later was 50 μm, the outer diameter of the cladding was 60 μm, and the outer diameter of the coating layer was 250 μm.

[0092] (Example 3) [First core material] As the first core material, silsesquioxane, the material described in (i) above, was prepared. Specifically, silsesquioxane "SR-13H" manufactured by Konishi Chemical Industry Co., Ltd. was used.

[0093] Diphenyl sulfoxide was used as a refractive index modifier.

[0094] Polysilsesquioxane was dissolved in ethyl acetate, a solvent, and mixed with diphenyl sulfoxide, a refractive index modifier. The solution was added dropwise, and the solvent was evaporated at 100°C to dry the mixture. The rod-shaped resin composition obtained by drying was used as the first core material. The concentration of the refractive index modifier in the first core material was 5% by mass.

[0095] [Second core material] The silsesquioxane used as the first core material (i.e., silsesquioxane "SR-13H" manufactured by Konishi Chemical Industry Co., Ltd.) was used as the second core material.

[0096] [Clad materials] The same cladding material as in Example 1 was used.

[0097] [Materials for forming a coating layer] The same coating layer formation material as in Example 1 was used.

[0098] [Production of POF] POF was prepared using the same method as in Example 1.

[0099] For the POF prepared in Example 3, the core diameter (outer diameter of the core) measured by the method described later was 50 μm, the cladding outer diameter was 60 μm, and the coating layer outer diameter was 250 μm.

[0100] (Example 4) [First core material] As the first core material, the polymer described in (ii) above was prepared. Specifically, the polymer described in (ii) above was synthesized based on Paz Pazos, Marta, “Synthesis and Characterization of Copolymers Based on 2,3,4,5,6-Pentafluorostyrene”, 2005, Doctor of Philosophy, University of Akron, Polymer Science.

[0101] Diphenyl sulfoxide was used as a refractive index modifier.

[0102] Polypentafluorostyrene was dissolved in acetone, a solvent, and mixed with diphenyl sulfoxide, a refractive index modifier. The solution was added dropwise, and the solvent was evaporated at 50°C to dry it out. The rod-shaped resin composition obtained by drying was used as the first core material. The concentration of the refractive index modifier in the first core material was 5% by mass. The rod-shaped resin composition was prepared under an inert gas atmosphere (nitrogen gas atmosphere).

[0103] [Second core material] The polypentafluorostyrene used as the first core material was also used as the second core material.

[0104] [Clad materials] Polymethylpentene (TPX DX845, manufactured by Mitsui Chemicals, Inc.) was used as the cladding material.

[0105] [Materials for forming a coating layer] The same coating layer formation material as in Example 1 was used.

[0106] [Production of POF] Using the first core material, second core material, cladding material, and coating layer forming material prepared by the method described above, a POF having the same structure as POF10 shown in Figure 1 was produced by melt spinning. In this example, the manufacturing apparatus shown in Figure 4 was used for the production of the POF.

[0107] In this embodiment, the melting temperature of the first core material was 200°C, the melting temperature of the second core material was 200°C, the melting temperature of the cladding material was 250°C, and the melting temperature of the material for forming the coating layer was 250°C. The temperature of the diffusion tube 120 was also set to 200°C. A core was formed from the first core material and the second core material. The temperature at which the second laminate, consisting of the core, cladding, and coating layer, was drawn down was 250°C.

[0108] For the POF prepared in Example 4, the core diameter (outer diameter of the core) measured by the method described later was 50 μm, the outer diameter of the cladding was 60 μm, and the outer diameter of the coating layer was 250 μm.

[0109] (Example 5) [First core material] As the first core material, the deuterated polymer described in (ii) above was prepared. Specifically, commercially available pentafluorostyrene monomer was purchased, and deuterated pentafluorostyrene monomer was synthesized with reference to Miyuki Hatano, Takahiro Nishimura, Hideki Yorimitsu, “Selective HD exchange at vinyl and methylidene groups with D2O catalyzed by an Iridium complex”, Organic Letters, 2016, 18, 15, 3674-3677. The obtained monomer was polymerized in the same manner as in Example 4, based on the literature Paz Pazos, Marta, “Synthesis and Characterization of Copolymers Based on 2,3,4,5,6-Pentafluorostyrene”, 2005, Doctor of Philosophy, University of Akron, Polymer Science. This yielded deuterated polypentafluorostyrene.

[0110] Diphenyl sulfoxide was used as a refractive index modifier.

[0111] Deuterated polypentafluorostyrene was dissolved in acetone, a solvent, and mixed with diphenyl sulfoxide, a refractive index modifier. The solution was added dropwise, and the solvent was evaporated at 50°C to dry it out. The rod-shaped resin composition obtained by drying was used as the first core material. The concentration of the refractive index modifier in the first core material was 5% by mass. The rod-shaped resin composition was prepared under an inert gas atmosphere (nitrogen gas atmosphere).

[0112] [Second core material] The deuterated polypentafluorostyrene used as the first core material was used as the second core material.

[0113] [Clad materials] The same cladding material as in Example 4 was used.

[0114] [Materials for forming a coating layer] The same coating layer forming material as in Example 4 was used.

[0115] [Production of POF] POF was prepared using the same method as in Example 4.

[0116] For the POF prepared in Example 4, the core diameter (outer diameter of the core) measured by the method described later was 50 μm, the outer diameter of the cladding was 60 μm, and the outer diameter of the coating layer was 250 μm.

[0117] (Example 6) [First core material] As the first core material, the polymer described in (iii) above was prepared.

[0118] Diphenyl sulfoxide was used as a refractive index modifier.

[0119] Polynonafluorovinyl biphenyl was dissolved in acetone, a solvent, and mixed with diphenyl sulfoxide, a refractive index modifier. The solution was added dropwise, and the solvent was evaporated at 50°C to dry it out. The rod-shaped resin composition obtained by drying was used as the first core material. The concentration of the refractive index modifier in the first core material was 5% by mass. The rod-shaped resin composition was prepared under an inert gas atmosphere (nitrogen gas atmosphere).

[0120] In Example 6, the suitability of the rod-shaped resin composition as a core material for POF was confirmed by verifying its heat resistance and transparency using the method described later.

[0121] [Heat resistance evaluation] The heat resistance of the POF cores in Examples 1-6 was evaluated by the following method. The heat resistance of the cores was evaluated using a rod-shaped first core material. The heat resistance of the core material was evaluated by measuring the glass transition temperature of the resin using a differential scanning calorimeter (DSC). A glass transition temperature of 80°C or higher was considered heat-resistant and the evaluation was given as "A". A TA Instruments Q2000 was used as the apparatus. The measurements were performed in a nitrogen atmosphere.

[0122] [Transparency Assessment] The transparency of the POF cores in Examples 1 to 6 was evaluated by the following method. The heat resistance of the core was evaluated using a rod-shaped first core material. The internal transmittance of the rod-shaped first core material was determined in accordance with JIS Z 8722. When the internal transmittance of a 10 mm thickness was 95% or higher, it was considered transparent and received an evaluation of "A".

[0123] [Refractive index of the core] The refractive index of the POF cores in Examples 1-5 for light at a wavelength of 850 nm was measured by the following method. The core material (rod-shaped first core material) was powdered and a film with a thickness of approximately 100 microns was fabricated by hot pressing. Using this film, the refractive index at a wavelength of 850 nm was determined using a Metricon Model 2010 / M prism coupler.

[0124] [Refractive index of cladding] The refractive index of the cladding of the POF in Examples 1-5 for light at a wavelength of 850 nm was measured using the same method as the refractive index of the core.

[0125] [Evaluation of numerical aperture (NA)] For POFs in Examples 1-5, the numerical aperture (NA) was measured using the Far Field Pattern (FFP) method with 850 nm light, in accordance with IEC60793-1-43 and IEC60793-2-40 sub-category A4h. A 6 m long POF was prepared, and 850 nm LED light was incident from one end. The light intensity distribution with respect to the angular position of the emitted light at a distance of 6 m was measured, and the NA was calculated. A numerical aperture of 0.19 or higher was considered good and received an evaluation of "A".

[0126] [Fustable] The melt-spindle properties of the core and cladding of the POF in Examples 1-3 were evaluated. The cores and cladding of Examples 1-3, which are thermosetting resins, were found to become highly viscous liquids when heated to 80-100°C, and when dropped, the liquid exhibited the property of forming threads (spindle properties). Spinning was performed at this temperature. If spinning was successful, it was evaluated as having melt-spindle properties and given an "A" rating.

[0127] [Evaluation of core diameter] The core diameter was measured using the NFP method with 850 nm wavelength light, in accordance with IEC60793-1-20 and IEC60793-2-40 sub-category A4h. A 6 m long POF was prepared, and 850 nm LED light was incident from one end. The light intensity distribution of the emitted light at a distance of 6 m was measured, and the diameter at 5% light intensity was calculated.

[0128] [Table 1]

[0129] [Table 2]

[0130] As shown in Tables 1 and 2, the core materials of Examples 1 to 6 exhibited excellent heat resistance and transparency, confirming their suitability as core materials for POF. Furthermore, it was confirmed that polysilsesquioxane and modified polysilsesquioxane, the resin components used in Examples 1 to 3, are thermosetting materials but can also be melt-spun. Additionally, when polysilsesquioxane used in Example 3 was melt-spun into fibers and the light transmission properties of these fibers at a wavelength of 850 nm were confirmed, light transmission was observed.

[0131] [Note] To summarize, one embodiment of the invention disclosed herein is as follows:

[0132] (1) Plastic optical fiber, The aforementioned plastic optical fiber includes a core that serves as an optical transmission section. The aforementioned core contains a resin material as its main component, The aforementioned resin material is at least one selected from the group consisting of (I) to (IV) below. Plastic optical fiber. (I) At least one cured product selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a portion of the silanol groups are capped, and deuterated polysilsesquioxane containing deuterium. (II) A polymer containing a constituent unit (A) represented by the following formula (1). (III) A polymer containing the constituent unit (B) represented by the following formula (2). (IV) A polymer containing a constituent unit (C) represented by the following formula (3). [ka] (In formula (1), R 1 ~R 3 (Each of these independently represents either hydrogen (H) or deuterium (D).) [ka] (In formula (2), R4 ~R 6 (Each of these independently represents either hydrogen (H) or deuterium (D).) [ka] (In formula (3), R 7 ~R 9 (Each of these independently represents either hydrogen (H) or deuterium (D).)

[0133] (2) The core further comprises a refractive index adjusting agent. The plastic optical fiber described in (1) above.

[0134] (3) The refractive index adjusting agent comprises at least one selected from the group consisting of germanium-containing compounds and sulfur-containing compounds. The plastic optical fiber described in (2) above.

[0135] (4) The refractive index adjusting agent comprises at least one selected from the group consisting of hexamethyldigermanium(IV) and diphenyl sulfoxide. The plastic optical fiber described in (3) above.

[0136] (5) The content ratio of the refractive index adjusting agent in the core is 1% by mass or more and 25% by mass or less. The plastic optical fiber described in (4) above.

[0137] (6) The resin material is (I) above, The polysilsesquioxane includes a polysilsesquioxane having a random structure, The modified polysilsesquioxane includes a modified polysilsesquioxane having a random structure, The deuterated polysilsesquioxane includes a deuterated polysilsesquioxane having a random structure. A plastic optical fiber as described in any one of the above (1) through (5).

[0138] (7) The aforementioned resin material is (I), and The aforementioned resin material includes a cured product of modified polysilsesquioxane. A plastic optical fiber as described in any one of the above (1) through (6).

[0139] (8) The aforementioned resin material is (I), and The aforementioned resin material includes a cured product of deuterated polysilsesquioxane. A plastic optical fiber as described in any one of the above (1) through (7).

[0140] (9) The aforementioned resin material is (II) above, and In the aforementioned structural unit (A), R 1 ~R 3 This represents deuterium (D). A plastic optical fiber as described in any one of the above (1) through (8).

[0141] (10) The aforementioned resin material is (III) above, and In the aforementioned structural unit (B), R 4 ~R 6 This represents deuterium (D). A plastic optical fiber as described in any one of the above (1) through (9).

[0142] (11) The resin material is the above (IV), and In the aforementioned constituent unit (C), R 7 ~R 9 This represents deuterium (D). A plastic optical fiber as described in any one of the above (1) through (10).

[0143] (12) The core further includes a cladding arranged on the outer circumference of the core. A plastic optical fiber as described in any one of the above (1) through (11).

[0144] (13) The resin material is (I) above, The aforementioned cladding mainly comprises cured silicone. The plastic optical fiber described in (12) above.

[0145] (14) The core further comprises a coating layer arranged on the outer periphery of the core, The coating layer mainly contains polycarbonate resin. A plastic optical fiber as described in any one of the above (1) through (13).

[0146] (15) The resin material is (I) above, The core has a refractive index distribution, In the aforementioned core, the maximum refractive index for light with a wavelength of 850 nm is 1.40 or greater and 1.43 or less. In the aforementioned core, the minimum refractive index for light with a wavelength of 850 nm is 1.39 or greater and 1.40 or less. A plastic optical fiber as described in any one of the above (1) through (14).

[0147] (16) A method for manufacturing plastic optical fibers, The aforementioned manufacturing method is The process includes heating the core material to adjust its viscosity to a range that allows for melt spinning, and forming a core from the core material by a melt spinning method. The core material comprises, as a main component, at least one selected from the group consisting of (i) to (iv) below: A method for manufacturing plastic optical fibers. (i) at least one selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a portion of the silanol groups are capped, and deuterated polysilsesquioxane containing deuterium. (ii) A polymer containing a constituent unit (A) represented by the following formula (1). (iii) A polymer containing the constituent unit (B) represented by the following formula (2). (iv) A polymer containing the constituent unit (C) represented by the following formula (3). [ka] (In formula (1), R 1 ~R 3 (Each of these independently represents either hydrogen (H) or deuterium (D).) [ka] (In formula (2), R 4 ~R 6 (Each of these independently represents either hydrogen (H) or deuterium (D).) [ka] (In formula (3), R 7 ~R 9 (Each of these independently represents either hydrogen (H) or deuterium (D).)

[0148] (17) The core material includes the material of (i), The polysilsesquioxane includes a polysilsesquioxane having a random structure, The modified polysilsesquioxane includes a modified polysilsesquioxane having a random structure, The deuterated polysilsesquioxane includes a deuterated polysilsesquioxane having a random structure. The manufacturing method described in (16) above.

[0149] (18) The core material includes the material of (i), The manufacturing method further includes curing the linear body formed from the core material by the melt spinning method with a base. The manufacturing method described in (16) or (17) above.

[0150] (19) The core material includes the material of (i), The polysilsesquioxane, the modified polysilsesquioxane, and the deuterated polysilsesquioxane are condensation-curing types that harden through a condensation reaction. The manufacturing method described in any one of (16) to (18) above.

[0151] (20) The viscosity of the core material during melt spinning is 100 Pa·s or more and 1000 Pa·s or less. The manufacturing method described in any one of (16) to (19) above. [Industrial applicability]

[0152] The POF disclosed herein includes a core formed from a novel core material and is expected to be used in a variety of applications, including those where conventional materials are unsuitable. [Explanation of Symbols]

[0153] 1a First core material 1b Second core material 1c Clad material 1d resin composition 2. Core inner layer 3 Core outer periphery 4. Laminate (core) 5 clad 6 Covering layer 7. Second layer 10 POF 11 cores 12 clad 13 Covering layer 101a First extruder 101b Second extruder 101c Third extruder 101d Fourth extruder 102a First containment area 102b Second containment area 102c Third containment area 102d Fourth containment unit 103a First extrusion section 103b Second extrusion section 103c Third extrusion section 104 Screw 105 Hopper 110 Room 1 120 Diffusion tube 130 Room 2 140 Room 3 150 nozzles 160 Cooling pipe 161 Interior space 170 Nip Roll 171,172 rolls 173,174,175 Guide Roll 176 Reel Roll 180 Displacement Gauge 1000 manufacturing equipment

Claims

1. Plastic optical fiber, The aforementioned plastic optical fiber includes a core that serves as an optical transmission section. The aforementioned core contains a resin material as its main component, The resin material is at least one selected from the group consisting of (I) to (IV) below. Plastic optical fiber. (I) At least one cured product selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a portion of the silanol groups are capped, and deuterated polysilsesquioxane containing deuterium. (II) A polymer containing a constituent unit (A) represented by the following formula (1). (III) A polymer containing a constituent unit (B) represented by the following formula (2). (IV) A polymer containing a constituent unit (C) represented by the following formula (3). 【Chemistry 1】 (In formula (1), R 1 ~R 3 (Each of these independently represents either hydrogen (H) or deuterium (D).) 【Chemistry 2】 (In formula (2), R 4 ~R 6 (Each of these independently represents either hydrogen (H) or deuterium (D).) 【Transformation 3】 (In formula (3), R 7 ~R 9 (Each of these independently represents either hydrogen (H) or deuterium (D).)

2. The core further comprises a refractive index adjusting agent. The plastic optical fiber according to claim 1.

3. The refractive index adjusting agent comprises at least one selected from the group consisting of germanium-containing compounds and sulfur-containing compounds. The plastic optical fiber according to claim 2.

4. The refractive index adjusting agent comprises at least one selected from the group consisting of hexamethyldigermanium(IV) and diphenyl sulfoxide. The plastic optical fiber according to claim 3.

5. The content ratio of the refractive index adjusting agent in the core is 1% by mass or more and 25% by mass or less. The plastic optical fiber according to claim 4.

6. The aforementioned resin material is (I), The polysilsesquioxane includes a polysilsesquioxane having a random structure, The modified polysilsesquioxane includes a modified polysilsesquioxane having a random structure. The deuterated polysilsesquioxane includes a deuterated polysilsesquioxane having a random structure. The plastic optical fiber according to claim 1.

7. The resin material is (I), and The aforementioned resin material includes a cured product of modified polysilsesquioxane. The plastic optical fiber according to claim 1.

8. The resin material is (I), and The aforementioned resin material includes a cured product of deuterated polysilsesquioxane. The plastic optical fiber according to claim 1.

9. The aforementioned resin material is (II), and In the aforementioned structural unit (A), R 1 ~R 3 This represents deuterium D. The plastic optical fiber according to claim 1.

10. The aforementioned resin material is (III) above, and In the constituent unit (B), R 4 to R 6 represents deuterium D, The plastic optical fiber according to claim 1.

11. The aforementioned resin material is (IV), and In the aforementioned structural unit (C), R 7 ~R 9 This represents deuterium D. The plastic optical fiber according to claim 1.

12. The core further includes a cladding arranged on the outer circumference of the core. The plastic optical fiber according to claim 1.

13. The aforementioned resin material is (I), The aforementioned cladding mainly comprises cured silicone. The plastic optical fiber according to claim 12.

14. The core further comprises a coating layer arranged on the outer periphery of the core, The coating layer mainly contains polycarbonate resin. The plastic optical fiber according to claim 1.

15. The aforementioned resin material is (I), The core has a refractive index distribution, In the aforementioned core, the maximum refractive index for light with a wavelength of 850 nm is 1.40 or more and 1.43 or less. In the aforementioned core, the minimum refractive index for light with a wavelength of 850 nm is 1.39 or greater and 1.40 or less. The plastic optical fiber according to claim 1.

16. A method for manufacturing plastic optical fibers, The aforementioned manufacturing method is The process includes heating the core material to adjust its viscosity to a range that allows for melt spinning, and forming a core from the core material by a melt spinning method. The core material comprises, as a main component, at least one selected from the group consisting of (i) to (iv) below: A method for manufacturing plastic optical fibers. (i) at least one selected from the group consisting of polysilsesquioxane, modified polysilsesquioxane in which at least a portion of the silanol groups are capped, and deuterated polysilsesquioxane containing deuterium. (ii) A polymer containing a constituent unit (A) represented by the following formula (1). (iii) A polymer containing a constituent unit (B) represented by the following formula (2). (iv) A polymer containing a constituent unit (C) represented by the following formula (3). 【Chemistry 1】 (In formula (1), R 1 ~R 3 (Each of these independently represents either hydrogen (H) or deuterium (D).) 【Chemistry 2】 (In formula (2), R 4 ~R 6 (Each of these independently represents either hydrogen (H) or deuterium (D).) 【Transformation 3】 (In formula (3), R 7 ~R 9 (Each of these independently represents either hydrogen (H) or deuterium (D).)

17. The core material includes the material of (i), The polysilsesquioxane includes a polysilsesquioxane having a random structure, The modified polysilsesquioxane includes a modified polysilsesquioxane having a random structure. The deuterated polysilsesquioxane includes a deuterated polysilsesquioxane having a random structure. The manufacturing method according to claim 16.

18. The core material includes the material of (i), The manufacturing method further includes curing the linear body formed from the core material by the melt spinning method with a base. The manufacturing method according to claim 16.

19. The core material includes the material of (i), The polysilsesquioxane, the modified polysilsesquioxane, and the deuterated polysilsesquioxane are condensation-curing types that harden through a condensation reaction. The manufacturing method according to claim 16.

20. The viscosity of the core material during melt spinning is 100 Pa·s or more and 1000 Pa·s or less. The manufacturing method according to claim 16.

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