Plastic molded article, plastic optical fiber, and method for manufacturing plastic optical fiber

Abstract

An object is to provide a plastic molded body that can be used as a raw material for manufacturing an optical fiber capable of reducing noise caused by return light. 【Solution means】The plastic molded body 10 of the present disclosure is a molded body of a polymer in which the total scattering loss α total [dB / km] is represented by the following formula (I), and α total =α1 iso +α2 iso +α aniso ···(I) Here, in the formula (I), α1 iso is isotropic scattering [dB / km] having no angular dependence, α2 iso is isotropic scattering [dB / km] having angular dependence, and α aniso is anisotropic scattering [dB / km]. The ratio (α2 total / α iso ) of the isotropic scattering α2 iso having angular dependence with respect to the total scattering loss α total is 0.75 or more and 0.95 or less.

Description

[Technical Field]

[0001] This disclosure relates to a plastic molded article, a plastic optical fiber, and a method for manufacturing a plastic optical fiber. [Background technology]

[0002] With the increase in network traffic, communication methods are shifting from conventional binary signals (e.g., NRZ (Non-Return to Zero)) to multi-level pulse amplitude modulation (PAM-X, X=3, 4, 6, 8, etc.). Multi-level amplitude modulation narrows the potential difference between each value, making amplitude noise a significant issue. In VCSELs (Vertical Cavity Surface Emitting Lasers), used as light sources in optical communication, emitted light is reflected from the end face of the optical fiber or the surface of the photodetector and re-enters the VCSEL as reflected light. This reflected light is known to generate noise.

[0003] Methods to reduce noise caused by reflected light include intentionally misaligning the VCSEL, the optical components for coupling the light emitted from the VCSEL to the optical fiber, and the optical fiber itself, cutting the end face of the optical fiber at an angle, and using an optical isolator. Furthermore, reducing noise caused by reflected light using an optical transmission system that employs a photodetector equipped with signal correction equipment, such as the one disclosed in Patent Document 1, is also being considered. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-151516 [Overview of the project] [Problems that the invention aims to solve]

[0005] Using optical isolators requires the proper placement of optical crystals and polarizers to rotate the polarization plane, making them unsuitable for communication transceivers where compactness is essential, and also increasing costs. Shifting the optical axis can lead to increased coupling loss and stray light. If signal correction is required, a correction device must be mounted on the receiver, resulting in a larger system due to the addition of components.

[0006] Therefore, it is desirable to reduce noise caused by reflected light not through the installation method of the optical fiber, additional components, or additional equipment, but through the optical fiber itself.

[0007] This disclosure has been made in view of the above, and aims to provide a plastic molded article that can be used as a raw material for manufacturing optical fibers that can reduce noise due to reflected light. Furthermore, it also aims to provide a plastic optical fiber that can reduce noise due to reflected light and a method for manufacturing such a plastic optical fiber. [Means for solving the problem]

[0008] The first aspect of this disclosure is: A plastic molded body, The plastic molded body has a total scattering loss α determined by measurement using the light scattering method. total [dB / km] is a molded polymer represented by the following formula (I), α total =α1 iso +α2 iso +α aniso ...(I) Here, in equation (I) above, α1 iso This is isotropic scattering [dB / km] that does not have angle dependence. α2 iso This is isotropic scattering with angle dependence [dB / km], and α aniso This is anisotropic scattering [dB / km] And, The total scattering loss α total The isotropic scattering α2 having the angular dependence with respect to iso The ratio of (α2 iso / α total ) is 0.75 or more and 0.95 or less.

[0009] The second aspect of the present disclosure is A plastic optical fiber having a core that is an optical transmission region, The core contains a polymer, The polymer is obtained by dropping the polymer within a temperature range of 150 to 400 ° C in a molten state and molding it into a cylindrical shape with a diameter of 10 mm and a length of 50 mm. The obtained molded body of the polymer is used as a test piece, and the total scattering loss α total [dB / km] is a polymer represented by the following formula (III), α total =α1 iso +α2 iso +α aniso ···(III) Here, in the formula (III), α1 iso Is isotropic scattering [dB / km] having no angular dependence, α2 iso Is isotropic scattering [dB / km] having an angular dependence, and α<00000​​​​​​​​​​​​​​​​​​​​​

[0011] A plastic molded article according to the first aspect of this disclosure can be used as a raw material for manufacturing plastic optical fibers that can reduce noise due to reflected light. A plastic optical fiber according to the second aspect of this disclosure can reduce noise due to reflected light. A manufacturing method according to the third aspect of this disclosure can manufacture plastic optical fibers that can reduce noise due to reflected light. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram showing an example of a plastic molded body according to Embodiment 1. [Figure 2] Figure 2 is a schematic diagram showing an example of a cross-sectional structure of a plastic optical fiber according to Embodiment 2. [Figure 3] Figure 3 is a schematic diagram showing a modified cross-sectional structure of a plastic optical fiber according to Embodiment 2. [Figure 4] Figure 4 is a schematic cross-sectional view showing an example of a manufacturing apparatus that can be used to manufacture plastic optical fibers according to Embodiment 2. [Figure 5A] Figure 5A is a schematic diagram illustrating isotropic scattering that does not have angle dependence. [Figure 5B] Figure 5B is a schematic diagram illustrating isotropic scattering with angle dependence. [Modes for carrying out the invention]

[0013] <Knowledge that forms the basis of this disclosure> As described in the [Background Technology] section, reflected light refers to light that is emitted from a light source, reflected by the end face of an optical fiber or the surface of a photodetector, and returns to the light source. As a result of studies on reducing this reflected light, the inventors have found that of the reflected light reflected from the end face of an optical fiber or the surface of a photodetector, only the amount of light corresponding to the spot size and divergence angle of the light emitted from the light source returns to the light source.

[0014] An optical fiber has a first end into which light emitted from a light source is incident, and a second end into which light that has passed through the optical fiber is emitted. In an optical fiber, the end from which light that becomes reflected light is emitted is the first end into which light emitted from the light source is incident. That is, as a result of diligent research, the inventors have found that in order to reduce reflected light, it is important to reduce the light density by scattering the light emitted from the first end of the optical fiber toward the light source. Here, the light emitted from the first end toward the light source includes both the light reflected at the first end and the light reflected at the second end. When the light emitted from the first end of the optical fiber toward the light source is scattered and the light density is reduced, the reflected light returning to the light source can be reduced, and thus noise can be reduced. Furthermore, the inventors have found that the microscopic non-uniform structure of the material constituting the optical fiber is related to scattering the light emitted from the first end of the optical fiber toward the light source in such a way that reflected light is effectively reduced. iso Considering that scattering is the sum of scattering originating from the non-uniform structure of the material and foreign matter, we also focused on the amount of foreign matter in the material (i.e., the ratio of luminance area).

[0015] Therefore, the inventors conducted diligent research and arrived at the present disclosure of a plastic molded article having a structure suitable as a raw material for manufacturing optical fibers that can reduce noise caused by reflected light.

[0016] <Embodiments of this Disclosure> [First Embodiment] The plastic molded body according to the first embodiment has a total scattering loss α determined by measurement using the light scattering method. total [dB / km] is a molded polymer represented by the following formula (I).

[0017] α total =α1 iso +α2 iso +α aniso ...(I)

[0018] Here, in equation (I) above, α1iso This is isotropic scattering [dB / km] that does not have angle dependence. α2 iso This is isotropic scattering with angle dependence [dB / km], and α aniso This is anisotropic scattering [dB / km] That is the case.

[0019] In the plastic molded article of the polymer according to the first embodiment, the total scattering loss α total Angle-dependent isotropic scattering α2 iso The ratio (α2 iso / α total The value of ) is between 0.75 and 0.95. Below, the total scattering loss α total Angle-dependent isotropic scattering α2 iso The ratio (α2 iso / α total ) to "Ratio α2 iso / α total It states, "."

[0020] Furthermore, isotropic scattering is synonymous with Rayleigh scattering. Isotropic scattering without angle dependence means that scattering occurs isotropically regardless of the angle (see Figure 5A). Isotropic scattering with angle dependence means that the scattering intensity differs depending on the angle due to interference between Rayleigh scattering from a small region with a non-uniform refractive index (see Figure 5B).

[0021] The term "light scattering method" refers specifically to static light scattering (SLS).

[0022] In this specification, the total scattering loss α determined by measurement using the light scattering method is defined as follows: total [dB / km] is a value measured using light with a wavelength of 633 nm.

[0023] Furthermore, the luminance area ratio (%) of the plastic molded article according to the first embodiment may be, for example, 1% or less.

[0024] In this specification, the luminance area ratio (%) is determined as follows: (1) A 532 nm continuous wave laser beam is incident on a rod-shaped plastic molded body, and an image of the molded body is acquired. (2) The ratio of the area of ​​regions with a luminance (a value between 0 and 255) of 100 or more to the total area of ​​the obtained image is defined as the luminance area ratio.

[0025] The total scattering loss α expressed by the above formula (I) is α total In this case, angle-dependent isotropic scattering α2 iso This represents the scattering loss originating from the heterogeneous structure, i.e., the ratio α2. iso / α total This represents the proportion of scattering loss originating from the heterogeneous structure to the total scattering loss. The plastic molded article according to the first embodiment has a ratio of α2 iso / α total Because the polymer molded article satisfies a ratio of 0.75 or more and 0.95 or less, when the plastic molded article according to the first embodiment is used as a raw material for plastic optical fibers, for example, as a raw material for producing the core, which is the optical transmission region of a plastic optical fiber (hereinafter referred to as "POF"), the light emitted from the first end of the POF toward the light source can be scattered in such a way that reflected light is effectively reduced. Therefore, the plastic molded article according to the first embodiment can be used as a raw material for producing a POF that can reduce noise due to reflected light.

[0026] Conventionally, for POFs, materials with high uniformity have been considered desirable in order to suppress the optical loss of the POF. Therefore, the ideal POF material is one in which the ratio of scattering loss originating from the heterogeneous structure to the total scattering loss, i.e., isotropic scattering α2 with angle dependence, is important. iso The material should have the smallest possible ratio, and the most ideal material has a ratio of α2 iso / α total It has been thought that the material has a ratio close to 0 (zero). However, unlike the material that was previously considered to be the ideal POF material, the ratio α2 iso / α totalAccording to the plastic molded article of Embodiment 1, which is a polymer molded article in which the ratio α2 is 0.75 or more and 0.95 or less, a POF that can reduce noise due to reflected light can be realized. Here, for example, by controlling the amount of foreign matter in the polymer so that the luminance area ratio is 1% or less, the polymer ratio α2 iso / α total It can be adjusted to a range of 0.75 or higher and 0.95 or lower.

[0027] In order to realize a POF that can further reduce noise caused by reflected light, in the plastic molded body according to Embodiment 1, ratio α2 iso / α total It may be 0.8 or higher.

[0028] In order to realize a POF that can further reduce noise caused by reflected light, in the plastic molded body according to Embodiment 1, ratio α2 iso / α total It may be 0.9 or less or 0.85 or less.

[0029] In the plastic molded article according to Embodiment 1, angle-dependent isotropic scattering α2 iso This may be 20 dB / km or more. This makes it possible to realize a POF that can further reduce noise due to reflected light. In order to realize a POF that can further reduce noise due to reflected light, angle-dependent isotropic scattering α2 iso This may be 25 dB / km or higher, or 28 dB / km or higher.

[0030] In the plastic molded article according to Embodiment 1, angle-dependent isotropic scattering α2 iso For example, it may be 100 dB / km or less or 50 dB / km or less.

[0031] In order to suppress excessive light loss, the total scattering loss α in the plastic molded body according to Embodiment 1 total The noise level is preferably 100 dB / km or less, and more preferably 50 dB / km or less.

[0032] In order to realize a POF that can further reduce noise due to reflected light, the total scattering loss α in the plastic molded body according to Embodiment 1 total For example, it may be 30 dB / km or higher.

[0033] Scattering originating from heterogeneous structures in solids can be expressed by the following equation (II), considering the interference effect of the scattered light from the multiple dipoles induced by the heterogeneous structure.

number

[0034] In the above equation (II), V V isotropic scattering intensity, a is the correlation length, k is the wave number. θ is the scattering angle. 〈η 2 > is dielectric constant fluctuation, and λ is wavelength That is the case.

[0035] The heterogeneous structure in a solid is determined by the correlation length a and dielectric constant fluctuations 〈η〉 in equation (II) above. 2 It can be evaluated by >.

[0036] It is preferable that the relationship between the scattering angle and scattering intensity obtained by measurement (wavelength: 633 nm) of the plastic molded body according to Embodiment 1 satisfies formula (II) above, and that the correlation length a of the polymer is 30 nm or more. This makes it possible to realize a POF that can further reduce noise due to reflected light. In order to realize a POF that can further reduce noise due to reflected light, the correlation length a may be 33 nm or more, 35 nm or more, or even 37 nm or more.

[0037] In order to reduce Rayleigh scattering, in the plastic molded article according to Embodiment 1, the correlation length a may be, for example, 400 nm or less, or 200 nm or less.

[0038] To improve the transparency of the plastic molded article and reduce transmission loss, in the plastic molded article according to Embodiment 1, the luminance area ratio (%) may be 0.8% or less, 0.6% or less, or 0.5% or less.

[0039] Furthermore, from a manufacturing standpoint, in the plastic molded article according to Embodiment 1, the luminance area ratio (%) may be greater than 0% and may be 0.1% or greater.

[0040] The relationship between the scattering angle and scattering intensity obtained by the light scattering method of the plastic molded body according to Embodiment 1 satisfies the above equation (II), and the dielectric constant fluctuation of the polymer <η 2 > is 0.5 × 10 -8 Preferably, it is 1.0 × 10 -8 The above is more preferable. This makes it possible to realize a POF that can further reduce noise due to reflected light. In order to realize a POF that can further reduce noise due to reflected light, dielectric constant fluctuation <η 2 > is 1.5 × 10 -8 It may be greater than or equal to 2.0 × 10 -8 The above is also acceptable. Furthermore, from the viewpoint of the refractive index of the plastic molded body, dielectric constant fluctuations <η 2 > is 1.5 × 10 -7 The following is also acceptable: 1 × 10 -7 The following is also acceptable.

[0041] The polymer constituting the plastic molded article according to Embodiment 1 preferably has, for example, a fluorine-containing aliphatic ring structure. The fluorine-containing aliphatic ring structure may be included in the main chain of the fluorine-containing polymer or in the side chain of the fluorine-containing polymer. The fluorine-containing polymer has, for example, a constituent unit (A) represented by the following formula (1). [ka]

[0042] In formula (1), R ff 1 ~R ff 4 each independently represents a fluorine atom, a perfluoroalkyl group having 1 to 7 carbon atoms, or a perfluoroalkyl ether group having 1 to 7 carbon atoms. R ff 1 and R ff 2 may be linked to form a ring. "Perfluoro" means that all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. In formula (1), the number of carbon atoms of the perfluoroalkyl group is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1. The perfluoroalkyl group may be linear or branched. Examples of the perfluoroalkyl group include a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, and the like.

[0043] In formula (1), the number of carbon atoms of the perfluoroalkyl ether group is preferably 1 to 5, more preferably 1 to 3. The perfluoroalkyl ether group may be linear or branched. Examples of the perfluoroalkyl ether group include a perfluoromethoxymethyl group, and the like.

[0044] R ff 1 and R ff 2 When they are linked to form a ring, the ring may be a 5-membered ring or a 6-membered ring. Examples of this ring include a perfluorotetrahydrofuran ring, a perfluorocyclopentane ring, a perfluorocyclohexane ring, and the like.

[0045] Specific examples of the structural unit (A) include, for example, structural units represented by the following formulas (A1) to (A8).

Chemical formula

[0046] The constituent unit (A) is preferably constituent unit (A2), that is, the constituent unit represented by the following formula (2), among the constituent units represented by the above formulas (A1) to (A8). [ka]

[0047] The fluorine-containing polymer may contain one or more constituent units (A). In the fluorine-containing polymer, the content of constituent units (A) is preferably 20 mol% or more, and more preferably 40 mol% or more, relative to the total of all constituent units. When constituent units (A) are present in a quantity of 20 mol% or more, the fluorine-containing polymer tends to have higher heat resistance. When constituent units (A) are present in a quantity of 40 mol% or more, the fluorine-containing polymer tends to have higher transparency and higher mechanical strength in addition to high heat resistance. In the fluorine-containing polymer, the content of constituent units (A) is preferably 95 mol% or less, and more preferably 70 mol% or less, relative to the total of all constituent units.

[0048] The constituent unit (A) is derived, for example, from a compound represented by the following formula (3). In formula (3), R ff 1 ~R ff 4 This is the same as formula (1). The compound represented by formula (3) can be obtained by known manufacturing methods, including, for example, the manufacturing method disclosed in Japanese Patent Publication No. 2007-504125. [ka]

[0049] Specific examples of compounds represented by formula (3) above include, for example, the compounds represented by the following formulas (M1) to (M8). [ka]

[0050] The fluorine-containing polymer may further contain other constitutional units in addition to the constitutional unit (A). Examples of the other constitutional units include the following constitutional units (B) to (D).

[0051] The constitutional unit (B) is represented by the following formula (4). [Chemical formula]

[0052] In formula (4), R 1 ~R 3 each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 7 carbon atoms. R 4 represents a perfluoroalkyl group having 1 to 7 carbon atoms. The perfluoroalkyl group may have a ring structure. A part of the fluorine atoms may be substituted with halogen atoms other than fluorine atoms. A part of the fluorine atoms in the perfluoroalkyl group may be substituted with halogen atoms other than fluorine atoms.

[0053] The fluorine-containing polymer may contain one or more kinds of the constitutional unit (B). In the fluorine-containing polymer, the content of the constitutional unit (B) is preferably 5 to 10 mol% based on the total of all constitutional units. The content of the constitutional unit (B) may be 9 mol% or less, or may be 8 mol% or less.

[0054] The constitutional unit (B) is derived from, for example, a compound represented by the following formula (5). In formula (5), R 1 ~R 4 is the same as in formula (4). The compound represented by formula (5) is a fluorine-containing vinyl ether such as perfluorovinyl ether. [Chemical formula]

[0055] The constitutional unit (C) is represented by the following formula (6). [Chemical formula]

[0056] In formula (8), R 5 ~R 8 Each of these independently represents a fluorine atom or a perfluoroalkyl group having 1 to 7 carbon atoms. The perfluoroalkyl group may have a ring structure. Some of the fluorine atoms may be substituted with halogen atoms other than fluorine atoms. Some of the fluorine atoms in the perfluoroalkyl group may be substituted with halogen atoms other than fluorine atoms.

[0057] The fluorine-containing polymer may contain one or more constituent units (C). In the fluorine-containing polymer, the content of constituent units (C) is preferably 5 to 10 mol% of the total amount of all constituent units. The content of constituent units (C) may be 9 mol% or less, or 8 mol% or less.

[0058] The constituent unit (C) is derived, for example, from a compound represented by the following formula (7). In formula (7), R 5 ~R 8 This is the same as formula (6). The compounds represented by formula (7) are fluorine-containing olefins such as tetrafluoroethylene and chlorotrifluoroethylene. [ka]

[0059] The constituent unit (D) is represented by the following formula (8). [ka]

[0060] In formula (8), Z is an oxygen atom, a single bond, or -OC(R 19 R 20 ) represents O-, R 9 ~R 20Each independently represents a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms. Some of the fluorine atoms may be substituted with halogen atoms other than fluorine atoms. Some of the fluorine atoms in a perfluoroalkyl group may be substituted with halogen atoms other than fluorine atoms. Some of the fluorine atoms in a perfluoroalkoxy group may be substituted with halogen atoms other than fluorine atoms. s and t are each independently integers from 0 to 5, and s+t is an integer from 1 to 6 (where Z is -OC(R 19 R 20 (In the case of O-, s+t may be 0.)

[0061] The constituent unit (D) is preferably represented by the following formula (9). Note that the constituent unit represented by the following formula (9) is the case in formula (8) above where Z is an oxygen atom, s is 0, and t is 2. [ka]

[0062] In formula (9), R 141 , R 142 , R 151 , and R 152 Each of these independently represents a fluorine atom, a C1-C5 perfluoroalkyl group, or a C1-C5 perfluoroalkoxy group. Some of the fluorine atoms may be substituted with halogen atoms other than fluorine. Some of the fluorine atoms in a perfluoroalkyl group may be substituted with halogen atoms other than fluorine. Some of the fluorine atoms in a perfluoroalkoxy group may be substituted with halogen atoms other than fluorine.

[0063] The fluorine-containing polymer may contain one or more constituent units (D). In the fluorine-containing polymer, the content of constituent units (D) is preferably 30 to 67 mol% of the total amount of all constituent units. The content of constituent units (D) may be, for example, 35 mol% or more, 60 mol% or less, or 55 mol% or less.

[0064] The constituent unit (D) is derived, for example, from a compound represented by the following formula (10). In formula (10), Z, R 9 ~R 18 , s and t are the same as in formula (8). The compound represented by formula (10) is a fluorine-containing compound having two or more polymerizable double bonds and capable of cyclization. [ka]

[0065] The constituent unit (D) is preferably derived from a compound represented by the following formula (11). In formula (11), R 141 , R 142 , R 151 , and R 152 This is the same as equation (9). [ka]

[0066] Specific examples of compounds represented by formula (10) or formula (11) include the following compounds. CF2=CFOCF2CF=CF2 CF2 = CFOCF(CF3)CF = CF2 CF2=CFOCF2CF2CF=CF2 CF2 = CFOCF2CF(CF3)CF = CF2 CF2 = CFOCF(CF3)CF2CF = CF2 CF2 = CFOCFClCF2CF = CF2 CF2 = CFOCCl2CF2CF = CF2 CF2=CFOCF2OCF=CF2 CF2 = CFOC(CF3)2OCF = CF2 CF2 = CFOCF2CF(OCF3)CF = CF2 CF2=CFCF2CF=CF2 CF2=CFCF2CF2CF=CF2 CF2=CFCF2OCF2CF=CF2 CF2 = CFOCF2CFClCF = CF2 CF2=CFOCF2CF2CCl=CF2 CF2 = CFOCF2CF2CF = CFCl CF2 = CFOCF2CF(CF3)CCl = CF2 CF2=CFOCF2OCF=CF2 CF2 = CFOCCl2OCF = CF2 CF2 = CClOCF2OCCl = CF2

[0067] The fluorine-containing polymer may further contain other constituent units besides constituent units (A) to (D), but it is preferable that it substantially contains no other constituent units besides constituent units (A) to (D). The statement that the fluorine-containing polymer substantially contains no other constituent units besides constituent units (A) to (D) means that the sum of constituent units (A) to (D) is 95 mol% or more, preferably 98 mol% or more, of the total number of constituent units in the fluorine-containing polymer.

[0068] The polymerization method for fluorine-containing polymers is not particularly limited, and general polymerization methods such as radical polymerization can be used. The polymerization initiator for polymerizing fluorine-containing polymers may be a totally fluorinated compound.

[0069] The glass transition temperature of the fluorine-containing polymer is, for example, greater than 105°C and 140°C or less, and may be 120°C or higher.

[0070] The shape of the plastic molded body according to Embodiment 1 is not particularly limited, but the plastic molded body according to Embodiment 1 may be, for example, rod-shaped. As an example, the plastic molded body according to Embodiment 1 may be a cylindrical plastic molded body 1 as shown in Figure 1.

[0071] The plastic molded article according to Embodiment 1 can be manufactured, for example, by the following method.

[0072] Prepare a polymer constituting the plastic molded article according to Embodiment 1, such as the fluorine-containing polymer described above, and a solvent capable of dissolving the polymer. If the polymer is a fluorine-containing polymer, a fluorine-based solvent may be used, for example. The polymer is heated and dissolved in the solvent, and the resulting solution is filtered, for example. This suppresses the incorporation of foreign matter contained in the polymer into the molded article. After that, the solvent is removed and the resulting polymer is melted, and the molten polymer can be molded into a desired shape by dropping it, for example, within a temperature range of 150 to 400°C. From the viewpoint of reducing foreign matter in the molten polymer, a temperature range of 270°C to 290°C is desirable. In this specification, the temperature range of 150 to 400°C is synonymous with a temperature range of 150°C or more and 400°C or less.

[0073] [Second Embodiment] Figure 2 is a schematic diagram showing an example of the cross-sectional structure of a POF according to the second embodiment. The POF 10 according to the second embodiment includes a core 11 which is an optical transmission region. The core 11 contains a polymer.

[0074] The polymer contained in core 11 is molded into a cylindrical shape with a diameter of 10 mm and a length of 50 mm by dropping the polymer from a molten state within a temperature range of 150 to 400°C. The resulting molded polymer is used as a test specimen, and the total scattering loss α is determined by measuring the test specimen using the light scattering method. total [dB / km] is a polymer represented by the following formula (III).

[0075] α total =α1 iso +α2 iso +α aniso ...(III)

[0076] Here, in equation (III) above, α1 iso This is isotropic scattering [dB / km] that does not have angle dependence. α2 iso This is isotropic scattering with angle dependence [dB / km], and α anisoThis is anisotropic scattering [dB / km] That is the case.

[0077] For the above polymer, the total scattering loss α total Angle-dependent isotropic scattering α2 iso The ratio (α2 iso / α total The value is between 0.75 and 0.95.

[0078] By providing a core 11 containing a polymer having the above-described characteristics, the POF 10 according to the second embodiment can reduce noise caused by reflected light.

[0079] The polymer contained in the core 11 of the POF10 according to Embodiment 2 can be the polymer that constitutes the plastic molded body according to Embodiment 1. Therefore, when the test piece used in the measurement by the light scattering method described above is considered to be the plastic molded body according to Embodiment 1, it is preferable that the polymer contained in the core 11 of the POF10 according to Embodiment 2 has the same configuration as the plastic molded body described in Embodiment 1.

[0080] As shown in Figure 2, the POF 10 according to the second embodiment may further include a cladding 12 arranged on the outer circumference of the core 11. A POF 10 having such a configuration preferably has a numerical aperture (NA) of 0.10 or more and 0.23 or less. Having such a numerical aperture allows the POF 10 according to the second embodiment to further reduce noise caused by reflected light. Here, the numerical aperture (NA) is determined as follows. (1) Prepare a 6m length of POF. (2) Light from an 850nm LED is incident from one end. (3) Measure the light intensity distribution with respect to the angular position of the emitted light 6m away (i.e., the light from the other end) and calculate the numerical aperture (NA). The numerical aperture (NA) is determined using methods compliant with IEC60793-1-43 and IEC60793-2-40 sub-category A4h. The above (1) to (3) are calculation methods using the FFP (Far Field Pattern) method. The larger the numerical aperture (NA), which is the maximum input / output angle at which light can propagate through an optical fiber, the wider the reflected light emitted from the optical fiber becomes, thereby reducing the coupling with light sources such as VCSELs.

[0081] The following provides a more detailed explanation of each component of POF10.

[0082] (Core 11) As described above, the core 11 is the region that transmits light (the optical transmission region). The core 11 is made of a material with a higher refractive index than the cladding 12. With this configuration, light incident on the core 11 is confined inside the core 11 by the cladding 12 and propagates within the POF 10.

[0083] Core 11 contains a polymer as described above. As described above, the polymer that constitutes the plastic molded article according to Embodiment 1 can be used as this polymer. Core 11 may contain the above polymer as its main component. Here, Core 11 containing the above polymer as its main component means that the polymer is the most abundant component by mass in Core 11. Core 11 may contain 75% by mass or more of the above polymer, 80% by mass or more, or 85% by mass or more.

[0084] Core 11 may further contain additives in addition to the polymer described above. The additives may be, for example, refractive index modifiers. That is, core 11 may be formed from a resin composition containing the polymer and additives such as refractive index modifiers. As the refractive index modifier, for example, known refractive index modifiers used in the material of core 11 of POF10 may be used. The material of core 11 may also contain other additives besides refractive index modifiers.

[0085] The diameter (outer diameter) of the core 11 is preferably 30 μm or more and 100 μm, and more preferably 40 μm or more and 70 μm or less.

[0086] (Clad 12) In the POF10 of this embodiment, the cladding 12 includes, for example, a polymer. The polymer included in the cladding 12 is not particularly limited, as long as it is a polymer with high transparency. An example of the polymer used in the cladding 12 may be the polymer used in the core 11.

[0087] Clad 12 may contain polymers as its main component. Here, "containing polymers as its main component" means that the polymer is the most abundant component by mass in Clad 12. Clad 12 may contain 80% by mass or more of polymers, 90% by mass or more, or 95% by mass or more. Clad 12 may consist solely of polymers. Clad 12 may also contain additives in addition to polymers.

[0088] For example, the polymer used in the cladding 12 can be a polymer that can be used in the core 11, i.e., a polymer that constitutes the plastic molded article according to Embodiment 1. Therefore, the polymer used in the cladding 12 may be a fluorine-containing polymer as exemplified by the polymer that constitutes the plastic molded article according to Embodiment 1.

[0089] The fluorine-containing polymer used in cladding 12 may further contain the constituent unit (E) represented by the following formula (12) and have an amorphous structure. [ka] (In formula (12), Z is an oxygen atom, a single bond, or -OC(R 31 R 32 ) represents O-, R 21 ~R 32Each of these independently represents a fluorine atom, a C1-C5 perfluoroalkyl group, or a C1-C5 perfluoroalkoxy group. "Perfluoro" means that all hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms. Some of the fluorine atoms may be replaced by halogen atoms other than fluorine. Some of the fluorine atoms in a perfluoroalkyl group may be replaced by halogen atoms other than fluorine. Some of the fluorine atoms in a perfluoroalkoxy group may be replaced by halogen atoms other than fluorine. s and t are each independently between 0 and 5, and s+t is an integer between 1 and 6 (where Z is -OC(R) 31 R 32 (In the case of O-, s+t may be 0.) u and v are independently either 0 or 1.

[0090] A fluorine-containing polymer containing the constituent unit (E) may further contain the constituent unit (F) represented by the following formula (13). [ka] (In formula (13), R 33 ~R 36 Each of these independently represents a fluorine atom or a perfluoroalkyl group having 1 to 7 carbon atoms. The perfluoroalkyl group may have a ring structure. Some of the fluorine atoms may be substituted with halogen atoms other than fluorine atoms. (Some of the fluorine atoms in the perfluoroalkyl group may be substituted with halogen atoms other than fluorine atoms.)

[0091] If the fluorine-containing polymer contained in cladding 12 is the copolymer described above, the ratio of constituent unit (E) to constituent unit (F) is arbitrary and not particularly limited.

[0092] The fluorine-containing polymer contained in cladding 12 is preferably at least one selected from the group consisting of fluorine-containing polymer A and fluorine-containing polymer B shown below.

[0093] Fluorine-containing polymer A contains the constituent unit (G) represented by the following formula (14) and the constituent unit (H) represented by the following formula (15). Note that in the following formula (14), R 23 , R 24 , R 31 , and R 32 This is the same as equation (12) above.

[0094] [ka] [ka] (In formula (15), R 37 ~R 40 Each of these independently represents a fluorine atom or a perfluoroalkyl group having 1 to 7 carbon atoms. The perfluoroalkyl group may have a ring structure. Some of the fluorine atoms may be substituted with halogen atoms other than fluorine atoms. (Some of the fluorine atoms in the perfluoroalkyl group may be substituted with halogen atoms other than fluorine atoms.)

[0095] Fluorine-containing polymer B contains the constituent unit (I) represented by the following formula (16). Note that in the following formula (16), R 21 ~R 24 , R 27 ~R 30 , R 31 , and R 32 This is the same as equation (12) above. [ka]

[0096] The fluorine-containing polymers A and B described above have very high transparency and can also have a very low refractive index compared to the typical refractive index of fluorine-containing polymers used as materials for the core 11. Therefore, when at least one selected from the group consisting of fluorine-containing polymers A and B is used as the fluorine-containing polymer for the cladding 12, it is possible to further reduce the refractive index while maintaining the high transparency of the cladding 12. As a result, the difference between the refractive index of the core 11 and the refractive index of the cladding 12 can be made even larger, further improving the light confinement effect of the cladding 12 within the core 11 and making it easier to achieve low transmission loss in the POF 10.

[0097] The second fluorine-containing polymer preferably contains the constituent unit (J) represented by the following formula (17). [ka] (In equation (17), m and n are any integers)

[0098] The fluorine-containing plasticizer is preferably a fluorine-containing polyether, and more preferably a perfluoropolyether.

[0099] Examples of perfluoropolyethers include organic compounds represented by the following formulas (18) or (19). In formulas (18) and (19), p1, q1, p2, and q2 are all arbitrary integers. CF3-[(O(CF3)CFCF2) p1 -(OCF2) q1 ]OCF3(18) CF3-[(OCF2CF2) p2 -(OCF2) q2 ]OCF3(19)

[0100] The glass transition temperature Tg2 of the polymer contained in cladding 12 is not particularly limited and may be, for example, greater than 105°C and less than or equal to 170°C, and may be greater than or equal to 125°C.

[0101] Furthermore, the outer diameter of the cladding 12 is preferably 40 μm or more and 120 μm or less, and more preferably 50 μm or more and 90 μm or less.

[0102] (modified version) Figure 3 is a schematic diagram showing a modified cross-sectional structure of POF according to Embodiment 2. The POF 20 shown in Figure 3 has a configuration in which a coating layer 21 is further provided on the outer circumference of the cladding 12 compared to the POF 10. The coating layer 21 is provided to improve the mechanical strength of the POF 20. For example, materials and configurations used as coating layers in known POFs may be applied to the coating layer 21. Examples of materials for the coating layer 21 include various engineering plastics such as polycarbonate, polyester, cycloolefin polymer, cycloolefin copolymer, polytetrafluoroethylene (PTFE), modified PTFE, and tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), or copolymers and mixtures thereof. The outer diameter of the coating layer 21 is preferably 150 μm to 400 μm, and more preferably 170 μm to 300 μm.

[0103] (POF manufacturing method) POF10 according to Embodiment 2 can be manufactured, for example, by the following method.

[0104] The method for manufacturing POF10 according to Embodiment 2 includes, for example, producing a core by melt spinning using a plastic molded body according to Embodiment 1.

[0105] In other words, an example of a method for manufacturing POF10 according to Embodiment 2 is: A core material is prepared using a plastic molded body according to Embodiment 1, and the core material is melted and extruded into a fibrous form to produce a fibrous molded body made of the core material. The cladding material is melted and extruded to cover the surface of the molded body, thereby producing a laminate in which the core material and the cladding material are stacked concentrically. Includes.

[0106] The core material can be prepared, for example, by melting a plastic molded body according to Embodiment 1 and adding necessary additives such as a refractive index adjuster.

[0107] When producing a fibrous molded body made of a core material, first, a first core material containing a refractive index adjusting agent may be extruded to form an inner core layer, and then a second core material may be extruded to cover the outer circumference of the inner core layer formed by the first core material. In this case, the refractive index adjusting agent contained in the first core material can be diffused toward the outer circumference of the core formed by the second core material to form a refractive index distribution in the core 11.

[0108] When manufacturing POF20 as shown in Figure 3, a laminate is created in which the core material and cladding material are stacked concentrically, and then a coating layer is further created to cover the laminate.

[0109] Figure 4 is a schematic cross-sectional view showing an example of a manufacturing apparatus that can be used to produce the POF20 shown in Figure 3.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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 dopants such as refractive index adjusters contained in the core inner layer 2 of the laminate 4 that pass 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.

[0114] 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.

[0115] The fourth extruder 101d comprises a fourth storage section 102d for containing the coating material 1d, 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 coating material 1d is supplied to the fourth storage section 102d through the hopper 105. The coating material 1d supplied to the fourth storage section 102d is heated and kneaded by the screw 104, softening and making it flowable. The softened coating material 1d is then extruded from the fourth storage section 102d by the screw 104.

[0116] The coating layer material 1d extruded from the fourth extruder 101d is supplied to the third chamber 140. Inside the third chamber 140, the coating layer 6 covering the outer periphery of the cladding 5 is formed by covering the surface of the laminate formed by the core 4 and cladding 5 with the coating layer material 1d.

[0117] The 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 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.

[0118] The laminate 7, discharged in a fiber-like manner 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 an opening. The 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 for measuring the outer diameter of the optical fiber may be further provided in the vicinity of the winding roll 176, for example, between the guide roll 175 and the winding roll 176. [Examples]

[0119] (Example 1) [Fabrication of plastic molded products] As a plastic molded product, a molded product of a fluorine-containing polymer was prepared.

[0120] As a fluorine-containing polymer, a polymer of perfluoro-4-methyl-2-methylene-1,3-dioxolane (PFMMD) was prepared. Perfluoro-4-methyl-2-methylene-1,3-dioxolane was first synthesized by synthesizing 2-carbomethyl-2-trifluoromethyl-4-methyl-1,3-dioxolane, fluorinating it, and then decarboxylating the resulting carboxylate salt. Perfluorobenzoyl peroxide was used as a polymerization initiator for the polymerization of perfluoro-4-methyl-2-methylene-1,3-dioxolane.

[0121] The synthesis of 2-carbomethyl-2-trifluoromethyl-4-methyl-1,3-dioxolane, the fluorination of 2-carbomethyl-2-trifluoromethyl-4-methyl-1,3-dioxolane, the synthesis of perfluoro-4-methyl-2-methylene-1,3-dioxolane, and the polymerization of perfluoro-4-methyl-2-methylene-1,3-dioxolane are described in detail below.

[0122] <Synthesis of 2-carbomethyl-2-trifluoromethyl-4-methyl-1,3-dioxolane> A 3 L three-necked flask equipped with a water-cooled condenser, a thermometer, a magnetic stirrer, and an isobaric dropping funnel were prepared. 139.4 g (1.4 mol total) of a mixture of 2-chloro-1-propanol and 1-chloro-2-propanol was placed in the flask. The flask was cooled to 0°C, and methyl trifluoropyruvate was slowly added, and the mixture was stirred for a further 2 hours. 100 mL of dimethyl sulfoxide (DMSO) and 194 g of potassium carbonate were added over 1 hour, and the mixture was stirred for a further 8 hours to obtain the reaction mixture. This reaction mixture was mixed with 1 L of water, the aqueous phase was separated, and this was further extracted with dichloromethylene. The dichloromethylene solution was then mixed with the organic reaction mixture phase, and the solution was dried over magnesium sulfate. After removing the solvent, 245.5 g of crude product was obtained. The crude product was fractionated under reduced pressure (12 Torr) to obtain 230.9 g of purified 2-carbomethyl-2-trifluoromethyl-4-methyl-1,3-dioxolane. The boiling point of the purified product was 77-78°C, and the yield was 77%. The identity of the obtained purified product as 2-carbomethyl-2-trifluoromethyl-4-methyl-1,3-dioxolane was confirmed by 1H NMR and 19 Confirmed by FNMR.

[0123] HNMR(ppm):4.2-4.6,3.8-3.6(CHCH2,multiplet,3H),3.85-3.88(COOCH3,multiplet,3H),1.36-1.43(CCH3,multiplet,3H) 19 FNMR (ppm): -81.3 (CF3, s, 3F)

[0124] <Fluorination of 2-carbomethyl-2-trifluoromethyl-4-methyl-1,3-dioxolane> 4 L of 1,1,2-trichlorotrifluoroethane was poured into a 10 L stirred reactor. Nitrogen was flowed into the reactor at a flow rate of 1340 cc / min and fluorine at a flow rate of 580 cc / min to create a nitrogen / fluorine atmosphere. After 5 minutes, 290 g of the previously prepared 2-carbomethyl-2-trifluoromethyl-4-methyl-1,3-dioxolane was dissolved in 750 mL of 1,1,2-trichlorotrifluoroethane solution, and this solution was added to the reactor at a rate of 0.5 ml / min. The reactor was cooled to 0°C. After adding all of the dioxolane over 24 hours, the flow of fluorine gas was stopped. After purging with nitrogen gas, potassium hydroxide aqueous solution was added until the mixture became weakly alkaline.

[0125] After removing volatile substances under reduced pressure, the reaction vessel was cooled, and then dried under reduced pressure at 70°C for 48 hours to obtain a solid reaction product. The solid reaction product was dissolved in 500 mL of water, and excess hydrochloric acid was added to separate it into an organic phase and an aqueous phase. The organic phase was separated and distilled under reduced pressure to obtain perfluoro-2,4-dimethyl-1,3-dioxolane-2-carboxylic acid. The boiling point of the main distillate was 103°C–106°C / 100 mmHg. The yield of fluorination was 85%.

[0126] <Synthesis of perfluoro-4-methyl-2-methylene-1,3-dioxolane> The above distillate was neutralized with an aqueous potassium hydroxide solution to obtain potassium-1,3-dioxolane perfluoro-2,4-dimethyl-2-carboxylate. This potassium salt was vacuum-dried at 70°C for 1 day. The salt was decomposed at 250°C to 280°C under a nitrogen or argon atmosphere. It was condensed in a refrigeration trap cooled to -78°C to obtain perfluoro-4-methyl-2-methylene-1,3-dioxolane in 82% yield. The boiling point of the product was 45°C / 760 mmHg. 19 The product was identified using FNMR and GC-MS.

[0127] 19 FNMR:-84ppm(3F,CF3),-129ppm(2F,=CF2) GC-MS:m / e244(Molecular ion)225,197,169,150,131,100,75,50.

[0128] <Polymerization of perfluoro-4-methyl-2-methylene-1,3-dioxolane> 100 g of perfluoro-4-methyl-2-methylene-1,3-dioxolane obtained by the above method and 1 g of perfluorobenzoyl peroxide were sealed in a glass tube. After the oxygen in the system was removed from this glass tube by freeze-degassing, argon was refilled and the tube was heated at 50°C for several hours. The contents became solid, but when heated further at 70°C overnight, a 100 g transparent rod-shaped substance was obtained.

[0129] The obtained transparent rod-shaped material was dissolved in Fluorinert FC-75 (manufactured by Sumitomo 3M), and the resulting solution was poured onto a glass plate to obtain a thin film of polymer. The glass transition temperature of the obtained polymer was 117°C, and it was completely amorphous. The transparent rod-shaped material was dissolved in hexafluorobenzene, and the product was purified by adding chloroform to precipitate it. The glass transition temperature of the purified polymer was approximately 131°C. This polymer was designated as a fluorine-containing polymer. This fluorine-containing polymer was dissolved in Opteon SF79 (manufactured by Mitsui Chemours Fluoroproducts Co., Ltd.), which was used as a solvent. The solution was filtered once through a 100 nm pore size filter "LPJ-CTA-001-N3" (manufactured by Rokitechno Co., Ltd.), and the filtrate was heated to 260°C to evaporate the solvent and dry it. The fluorine-containing polymer obtained after drying and filtration was melted and molded into a rod shape by dropping it at 270°C for 60 hours. The resulting molded body was designated as the plastic molded body of Example 1.

[0130] [Refractive Index Adjuster] Chlorotrifluoroethylene oligomer (molecular weight 585) was used as a refractive index modifier. Specifically, Daikin Industries' "Dai-Floil #10" was distilled, and only the component with a molecular weight of 585 was isolated. The isolated component with a molecular weight of 585 was filtered through a 40 nm pore size filter "DFA1ANDESW44" (manufactured by PALL) to obtain the refractive index modifier.

[0131] [First core material] The plastic molded body prepared by the above method was dissolved in the solvents Bartrell XF-UP and Opteon SF79 (both solvents manufactured by Mitsui Chemours Fluoroproducts). The solution was filtered twice through a 100 nm pore size filter "LPJ-CTA-001-N3" (manufactured by Rokitechno), and the filtrate was dropped into a Hastelloy container heated to 260°C to evaporate the solvent and dry it out. The fluorine-containing polymer obtained after drying and filtration treatment and the above refractive index modifier were melt-mixed at 260°C to prepare a resin composition. The concentration of the refractive index modifier in the obtained resin composition was 12% by mass. This resin composition was used as the first core material.

[0132] [Second core material] The plastic molded body produced by the above method was filtered using the same method as when the first core material was produced, and the fluorine-containing polymer after filtration was used as the second core material.

[0133] [Clad material] A fluorine-containing polymer was prepared as a cladding material. "Teflon AF1600" (manufactured by Mitsui Chemours Fluoroproducts), used as the cladding material, and "Fomblin YR" (manufactured by Solvay), used as a viscosity modifier, were dissolved in the solvents Bartrell XF-UP and Opteon SF79 (both solvents manufactured by Mitsui Chemours Fluoroproducts). The mixing ratio of "Teflon AF1600" to "Fomblin YR" was 7:3 by mass. The resulting solution was filtered through a 300nm pore size filter "LPA-SLF-003-N2" (manufactured by Rokitechno), and the filtrate was dropped into a Hastelloy container heated to 260°C to evaporate the solvent and allow it to dry. The resulting resin composition was used as the cladding material.

[0134] [Coating layer material] Xylex (manufactured by SABIC, glass transition temperature: 113°C) was used as the coating layer material.

[0135] [Production of POF] Using the first core material, second core material, cladding material, and coating layer material prepared by the method described above, an optical fiber having the same configuration as POF20 shown in Figure 3 was fabricated by melt spinning. In this example, the manufacturing apparatus shown in Figure 4 was used for the production of the POF.

[0136] In this embodiment, the inner diameter (diameter) of the diffusion tube 120 was 6.3 mm. The length of the diffusion tube 120 was set so that the diffusion time was 120 min.

[0137] In this embodiment, the melting temperature of the first core material was 250°C, the melting temperature of the second core material was 255°C, the melting temperature of the cladding material was 260°C, and the melting temperature of the coating layer material was 240°C. The temperature of the diffusion tube 120 was set to 275°C. A core was formed from the first core material and the second core material. The temperature at which the laminate 7, consisting of the core, cladding, and coating layer, was drawn down was 240°C.

[0138] The volume ratios of each material extruded were as follows: 1 part first core material, 1.04 parts second core material, 0.705 parts cladding material, and 40.438 parts coating layer material.

[0139] In the first chamber 110 shown in Figure 4, the temperature of the merging mold used when covering the core inner layer formed of the first core material with the second core material was set to 260°C. In the second chamber 130 shown in Figure 4, the temperature of the merging mold used when covering the core with the cladding material was set to 205°C. In the third chamber 140 shown in Figure 4, the temperature of the merging mold used when covering the surface of the laminate formed of the core and cladding with the coating layer material was set to 250°C.

[0140] For the POF fabricated in Example 1, the core diameter (outer diameter of the core) measured by the method described below was 50 μm, the thickness of the second region of the core was 2.5 μm, the outer diameter of the cladding was 62 μm (i.e., the thickness of the cladding was 6.0 μm), and the outer diameter of the coating layer was 250 μm.

[0141] (Comparative Example 1) Instead of the plastic molded body used in Example 1, synthetic quartz SUPRASIL-F300 (transparent synthetic quartz for optical components manufactured by Shin-Etsu Quartz Co., Ltd. using the CVD method) was used. The optical fiber in Comparative Example 1 was fabricated by melt spinning.

[0142] (Comparative Example 2) In Comparative Example 2, synthetic quartz (synthetic quartz produced by the slurry casting (SC) method by Hubei Industrial Co., Ltd.) was used instead of the plastic molded body used in Example 1. The optical fiber in Comparative Example 2 was fabricated by melt spinning.

[0143] (Comparative Example 3) The plastic molded article was prepared in the same manner as in Example 1, except that CYTOP (manufactured by AGC Inc.) was used instead of the fluorine-containing polymer used in Example 1. The POF of Comparative Example 3 was prepared in the same manner as in Example 1, except that the plastic molded article of Comparative Example 3 was used instead of the plastic molded article of Example 1.

[0144] (Comparative Example 4) A plastic molded article was prepared in the same manner as in Example 1, except that polymethyl methacrylate (PMMA) was used instead of the fluorine-containing polymer used in Example 1.

[0145] (Comparative Example 5) A plastic molded article was prepared in the same manner as in Example 1, except that trichloroethyl methacrylate (TCEMA) was used instead of the fluorine-containing polymer in Example 1, and the filtrate after filtration was heated to 150°C to evaporate the solvent. The POF of Comparative Example 5 was prepared in the same manner as in Example 1, except that the plastic molded article of Comparative Example 5 was used instead of the plastic molded article of Example 1.

[0146] (Comparative Example 6) The plastic molded body was prepared in the same manner as in Example 1, except that the filter used for filtering the fluorine-containing polymer solution was changed to a filter with a pore size of 1000 nm (Fluorinert membrane FALP, manufactured by Merck). The POF of Comparative Example 6 was prepared in the same manner as in Example 1, except that the plastic molded body of Comparative Example 6 was used instead of the plastic molded body of Example 1.

[0147] (Comparative Example 7) In the filtration of the fluorine-containing polymer solution, the filter used was changed to a filter with a pore size of 1000 nm (Fluorinert membrane FALP, manufactured by Merck), and the temperature at which the fluorine-containing polymer obtained after drying and filtration was molded was changed to 290°C. A plastic molded article was then prepared in the same manner as in Example 1. The POF of Comparative Example 7 was prepared in the same manner as in Example 1, except that the plastic molded article of Comparative Example 7 was used instead of the plastic molded article of Example 1.

[0148] (Comparative Example 8) A plastic molded article was prepared in the same manner as in Example 1, except that a copolymer of PFMMD and chlorotrifluoroethylene (CTEF) was used instead of the fluorine-containing polymer used in Example 1. The POF of Comparative Example 8 was prepared in the same manner as in Example 1, except that the plastic molded article of Comparative Example 8 was used instead of the plastic molded article of Example 1.

[0149] (Evaluation of scattering properties of plastic molded materials and synthetic quartz) [Method for preparing test specimens] For the plastic molded articles of Example 1, Comparative Example 3, Comparative Example 4, and Comparative Examples 6-8, the last obtained lot-shaped material was processed into a cylindrical shape with a diameter of 10 mm and a length of 50 mm to prepare test specimens for light scattering testing. In addition, for the synthetic quartz of Comparative Examples 1 and 2, and the plastic molded article of Comparative Example 5, the material was processed into a cylindrical shape with a diameter of 20 mm (Comparative Example 1), a diameter of 16 mm (Comparative Example 2), a diameter of 30 mm (Comparative Example 5), and a length of 50 mm to prepare test specimens for light scattering testing and evaluation of the luminance area ratio.

[0150] [Light scattering test] The test specimens of Example 1 and Comparative Examples 1-8 were placed in a container. Dimethyl silicone oil (Momentive) was then added to the container containing the test specimens, immersing them in the oil. A 633 nm laser beam was then shone onto the curved surface of the molded body. The scattered light from the molded body was measured using a dynamic light scattering photometer DLS-8000 (Otsuka Electronics) to determine the scattering intensity at 10° intervals within the scattering angle range of 70-140°.

[0151] [Method for evaluating the luminance area ratio] The luminance area ratios of the plastic molded articles of Example 1 and Comparative Examples 3-8 and the synthetic quartz of Comparative Examples 1 and 2 were determined as follows.

[0152] A 532nm continuous-wave laser beam was irradiated onto a molded body or synthetic quartz. Specifically, the continuous-wave laser beam was irradiated from the bottom surface of the cylindrical molded body or synthetic quartz described above. Images were then acquired of the side surface of the molded body or synthetic quartz using a VHX8000 (manufactured by Keyence). The luminance area ratio was defined as the ratio of the area of ​​regions with a luminance of 100 or more to the total area of ​​the image. A more detailed method is as follows.

[0153] In a darkroom, a semiconductor laser device (THORLABS PL201, wavelength: 532nm) was used to irradiate the cylindrical test specimen (plastic molded body or synthetic quartz) described above with laser light from one bottom surface. The laser light intensity was adjusted to within 860mW ± 15%. The test specimen irradiated with laser light was then photographed in a darkroom using a VHX-8000 (KEYENCE microscope) from a direction intersecting the direction of light propagation, i.e., from the side of the cylindrical test specimen, under conditions of shutter speed 100ms and gain 18dB, and image data was acquired. The ratio of the area of ​​regions with a luminance (a value between 0 and 255) of 100 or more to the total area of ​​the image was defined as the luminance area ratio. The results are shown in Table 1.

[0154] (Evaluation of POF Noise (Measurement of BER (Bit Error Rate) Value)) Using a BER tester (manufactured by VeEX), light with a wavelength of 850 nm was incident on one end of a POF (length: 3 m), and the light emitted from the other end of the optical fiber was received to measure the bit error rate. The results are shown in Table 1. In Table 1, "Communication impossible" means that the BER is 10 -10 or more. "No measurement result" means that the BER has not been measured.

Table 1

[0155] As shown in Table 1, the POF produced using the plastic molded body of Example 1 as a raw material has excellent BER values compared to the optical fibers of Comparative Examples 1 to 7, and it was confirmed that the noise was reduced.

[0156] [Appendix] Summarizing the above, one form of the invention of the present disclosure is as follows.

[0157] (1) A plastic molded body, The total scattering loss α total [dB / km] obtained by measurement using the light scattering method is a molded body of a polymer represented by the following formula (I), α total = α1 iso + α2 iso + α aniso ···(I) Here, in the above formula (I), α1 iso is isotropic scattering [dB / km] having no angular dependence, α2 iso is isotropic scattering [dB / km] having angular dependence, and α aniso is anisotropic scattering [dB / km] and the total scattering loss α totalThe isotropic scattering α2 having the angle dependence for the above iso The ratio (α2 iso / α total ) is 0.75 or greater and 0.95 or less. Plastic molded body.

[0158] (2) The brightness area ratio (%) of the aforementioned plastic molded body is 1% or less. The plastic molded article described in (1) above.

[0159] (3) The angle-dependent isotropic scattering α2 iso However, it is 20 dB / km or higher. The plastic molded article described in (1) or (2) above.

[0160] (4) The total scattering loss α total However, it is less than 100 dB / km. A plastic molded article as described in any one of the above items (1) to (3).

[0161] (5) The total scattering loss α total However, it is less than 50 dB / km. The plastic molded article described in (4) above.

[0162] (6) The relationship between the scattering angle and scattering intensity obtained by measurement of the plastic molded body by light scattering satisfies the following equation (II):

number

[0163] (7) The relationship between the scattering angle and the scattering intensity obtained by measuring the plastic molded article by the light scattering method satisfies the following formula (II):

Number

[0164] (8) The dielectric fluctuation of the plastic molded article is 1.0×10 -8 or more. The plastic molded article according to (7) above.

[0165] (9) The plastic molded article is an amorphous polymer. The plastic molded article according to any one of (1) to (8) above.

[0166] (10) A plastic optical fiber having a core that is an optical transmission region, The core contains a polymer, The polymer is prepared by dropping the molten polymer, which is in a temperature range of 150 to 400°C, into a cylindrical shape with a diameter of 10 mm and a length of 50 mm. The resulting molded polymer is used as a test specimen, and the total scattering loss α is determined by measuring the test specimen using the light scattering method. total [dB / km] is a polymer represented by the following formula (III), α total =α1 iso +α2 iso +α aniso ...(III) Here, in equation (III) above, α1 iso This is isotropic scattering [dB / km] that does not have angle dependence. α2 iso This is isotropic scattering with angle dependence [dB / km], and α aniso This is anisotropic scattering [dB / km] and For the polymer, the total scattering loss α total The isotropic scattering α2 having the angle dependence for the above iso The ratio (α2 iso / α total ) is 0.75 or greater and 0.95 or less. Plastic optical fiber.

[0167] (11) The core further comprises a cladding arranged on the outer circumference of the core, The numerical aperture (NA) of the aforementioned plastic optical fiber is 0.10 or more and 0.23 or less. The plastic optical fiber described in (10) above.

[0168] (12) A method for manufacturing a plastic optical fiber having a core that is an optical transmission region, The manufacturing method includes producing the core by melt spinning using a plastic molded body described in any one of the above items (1) to (9). A method for manufacturing plastic optical fibers. [Industrial applicability]

[0169] The POF of this disclosure is suitable as an optical fiber that requires high speed and high capacity because it can reduce reflected light and suppress noise generation. [Explanation of symbols]

[0170] 1 Plastic molded body 1a First core material 1b Second core material 1c Clad material 1d Covering layer material 2. Core inner layer 3 Core outer periphery 4. Laminate (core) 5 clad 6 Covering layer 7 Laminate 10, 20 POF 11 cores 12 clad 21 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. A plastic molded body, The plastic molded body has a total scattering loss α determined by measurement using the light scattering method. total [dB / km] is a molded article of a polymer represented by the following formula (I), a total =a 1 iso +a 2 iso +a aniso ・・・(I) Here, in equation (I) above, α 1 iso is the isotropic scattering [dB / km] that has no angular dependence, α 2 iso This is isotropic scattering with angle dependence [dB / km], and α aniso Anisotropic scattering [dB / km] And, The total scattering loss α total The isotropic scattering α with respect to the angle dependence 2 iso The ratio (α 2 iso / α total ) is 0.75 or higher and 0.95 or lower. Plastic molded body.

2. The brightness area ratio (%) of the aforementioned plastic molded body is 1% or less. The plastic molded article according to claim 1.

3. The angle-dependent isotropic scattering α 2 iso However, it is 20 dB / km or higher. The plastic molded article according to claim 1.

4. The total scattering loss α total However, it is less than 100 dB / km. The plastic molded article according to claim 1.

5. The total scattering loss α total However, it is less than 50 dB / km. The plastic molded article according to claim 4.

6. The relationship between the scattering angle and scattering intensity obtained by measurement of the aforementioned plastic molded body by light scattering satisfies the following equation (II): 【Number 1】 Here, in equation (II) above, V V isotropic scattering intensity, a is the correlation length, k is the wave number. θ is the scattering angle. 〈η 2 > is dielectric constant fluctuation, and λ is wavelength And, The correlation length of the polymer is 30 nm or more. The plastic molded article according to claim 1.

7. The relationship between the scattering angle and scattering intensity obtained by measurement of the aforementioned plastic molded body by light scattering satisfies the following equation (II): [Math 1] Here, in equation (II) above, V V isotropic scattering intensity a is the correlation length, k is the wave number. θ is the scattering angle. 〈η 2 > is dielectric constant fluctuation, and λ is wavelength And, The dielectric constant fluctuation of the polymer is 0.5 × 10 -8 That's all. The plastic molded article according to claim 1.

8. The dielectric constant fluctuation of the aforementioned plastic molded body is 1.0 × 10 -8 That's all. The plastic molded article according to claim 7.

9. The aforementioned plastic molded body is an amorphous polymer. The plastic molded article according to claim 1.

10. A plastic optical fiber having a core that is an optical transmission region, The core comprises a polymer, The polymer is prepared by dropping the molten polymer, which is in a temperature range of 150 to 400°C, into a cylindrical shape with a diameter of 10 mm and a length of 50 mm. The resulting molded polymer is used as a test piece, and the total scattering loss α is determined by measuring the test piece using the light scattering method. total [dB / km] is a polymer represented by the following formula (III), a total =a 1 iso +a 2 iso +a aniso ・・・(III) Here, in equation (III) above, α 1 iso This is isotropic scattering [dB / km] that does not have angle dependence. α 2 iso This is isotropic scattering with angle dependence [dB / km], and α aniso Anisotropic scattering [dB / km] and For the polymer, the total scattering loss α total The isotropic scattering α with respect to the angle dependence 2 iso The ratio (α 2 iso / α total ) is 0.75 or higher and 0.95 or lower. Plastic optical fiber.

11. The core further comprises a cladding arranged on the outer circumference of the core, The numerical aperture (NA) of the aforementioned plastic optical fiber is 0.10 or more and 0.23 or less. The plastic optical fiber according to claim 10.

12. A method for manufacturing a plastic optical fiber having a core that is an optical transmission region, The manufacturing method includes producing the core by melt spinning using a plastic molded body according to any one of claims 1 to 8. A method for manufacturing plastic optical fibers.

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