Optical fiber supported resin molded body and method for manufacturing the same

Abstract

To further improve the measurement accuracy of resin molded bodies supporting optical fibers. [Solution] The invention comprises a long core material, one or more optical fibers located within the core material and extending in the axial direction of the core material, and an adhesive portion located in at least a part of the space between the core material and the optical fibers. The core material contains a polypropylene resin, the optical fibers have a polyimide resin coating layer, and the adhesive portion is a cured product of a base-adhesive polypropylene resin composition.

Description

[Technical Field]

[0001] The present invention relates to a resin molded body supporting optical fibers and a method for manufacturing the same. [Background technology]

[0002] There is a resin molded body supporting optical fibers, which has a long core material (e.g., a resin tube) and optical fibers embedded in the core material in a linear or spiral manner so as to extend axially. The resin molded body supporting optical fibers can constantly monitor changes in bending, elongation, and torsional strain, as well as pressure and temperature changes, that occur in the core material based on frequency or phase changes of Rayleigh scattering of the optical fibers. In resin molded bodies supporting optical fibers, it is necessary to fix the optical fibers within the core material. For example, Patent Document 1 proposes a resin molded body supporting optical fibers, which comprises a cylindrical resin tube, one or more optical fibers located within the wall of the resin tube and extending in the axial direction of the resin tube, and an adhesive portion located in at least a portion between the outer surface of the optical fibers and the resin tube. According to the invention of Patent Document 1, the adhesive strength between the optical fibers and the resin tube is improved. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-134116 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, in resin molded bodies supporting optical fibers, it is necessary to securely fix the optical fibers within the core material. Therefore, the present invention aims to more securely fix the optical fiber within the core material. [Means for solving the problem]

[0005] The present invention has the following aspects. <1> An optical fiber-carrying resin molded article comprising: a long core material; one or more optical fibers positioned within the core material and extending in the axial direction of the core material; and an adhesive portion positioned in at least a part between the core material and the optical fiber, wherein the core material contains a polypropylene-based resin, the optical fiber has a coating resin layer made of a polyimide-based resin, and the adhesive portion is a cured product of a base-adhesive polypropylene-based resin composition. <2> The optical fiber-carrying resin molded article according to <1>, wherein the base-adhesive polypropylene-based resin composition contains imine-modified polypropylene. <3> In the adhesive portion, with respect to the absorbance peak height α at 1168 cm -1 measured by a Fourier transform infrared spectrophotometer, the ratio (β / α) of the absorbance peak height β at 2120 cm -1 thereto is 0.6 or more and 0.9 or less, the optical fiber-carrying resin molded article according to <1> or <2>. <4> In the adhesive portion, with respect to the absorbance peak height α at 1168 cm -1 measured by a Fourier transform infrared spectrophotometer, the ratio (γ / α) of the absorbance peak height γ at 2160 cm -1 thereto is 0.20 or more and 0.27 or less, the optical fiber-carrying resin molded article according to any one of <1> to <3>. <5> The optical fiber-carrying resin molded article according to any one of <1> to <4>, wherein in a cross section perpendicular to the axial direction, the ratio of the cross-sectional area F of the optical fiber to the cross-sectional area G of the adhesive portion is 0.1% or more and 6% or less. <6> The optical fiber-carrying resin molded article according to any one of <1> to <5>, wherein the adhesive portion contains acrylic-modified polytetrafluoroethylene. <7> The optical fiber-carrying resin molded article according to <6>, wherein the content of the acrylic-modified polytetrafluoroethylene is 1% by mass or more and 16% by mass or less based on the total mass of the adhesive portion. <8> The optical fiber-carrying resin molded article according to any one of <1> to <7>, wherein a melt flow rate (MFR) of the adhesive portion, measured in accordance with Method A of ISO 1133 at 230°C under a load of 2.16 kg, is not less than 0.05 g / 10min. and not more than 4.0 g / 10min.. <9> The base-adhesive polypropylene-based resin composition, the optical fiber, and a core material composition containing the polypropylene-based resin are supplied to an extrusion molding machine, The method for producing an optical fiber-carrying resin molded article according to any one of <1> to <8>, comprising a step of melting the core material composition and the base-adhesive polypropylene-based resin composition, extruding the molten composition together with the optical fiber into an elongated shape, and cooling the extrudate to obtain the optical fiber-carrying resin molded article. [Effects of the Invention]

[0006] According to the optical fiber-carrying resin molded article of the present invention, an optical fiber can be more reliably fixed inside a core material. [Brief Description of the Drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing an optical fiber-carrying resin molded article according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view perpendicular to an axis O1 in FIG. 1. [Figure 3] FIG. 3 is an enlarged view showing one example of a region s in FIG. 2. [Figure 4] FIG. 4 is an enlarged view showing another example of the region s in FIG. 2. [Figure 5] FIG. 5 is a cross-sectional view showing one example of an optical fiber. [Figure 6] FIG. 6 is a perspective view showing an optical fiber-carrying resin molded article according to another embodiment of the present invention. [Mode for Carrying Out the Invention]

[0008] (Optical Fiber-Carrying Resin Molded Article) The optical fiber-supported resin molded body of the present invention comprises a core material and one or more optical fibers located within the core material and extending in the direction of the tube axis of the core material. An embodiment of the optical fiber-supported resin molded body of the present invention will be described below. The optical fiber-supported resin molded body 10 in Figure 1 is a long, cylindrical resin tube. The optical fiber-supported resin molded body 10 has a cylindrical core material 11 and an optical fiber 12 extending in the direction of the core material 11's axis (tube axis) O1 within the cylindrical wall 11A of the core material 11. That is, in the optical fiber-supported resin molded body 10, the optical fiber 12 is embedded in the cured resin that constitutes the core material 11. As shown in Figures 2-3, an adhesive portion 16 is located between the core material 11 and the optical fiber 12.

[0009] The number of optical fibers 12 inside the cylindrical wall 11A may be one or more. Preferably, there may be two or more optical fibers 12 inside the cylindrical wall 11A, and more preferably four or more. If there are two or more optical fibers 12, bending displacement can be detected more effectively. If there are four or more optical fibers 12, torsional and flattening displacement can be detected more effectively. Preferably, there may be 20 or fewer optical fibers 12 inside the cylindrical wall 11A. If the number of optical fibers 12 is below the above upper limit, the mechanical strength of the core material 11 can be further increased. It is preferable that the optical fiber 12 is located within 25% of the thickness of the cylindrical wall 11A from the center in the thickness direction (i.e., the point where the thickness is divided in half) toward the surface. This prevents the optical fiber 12 from being exposed to the outside of the core material 11 when the surface of the core material 11 is scraped during the installation of the optical fiber-supported resin molded body 10, thus reducing the risk of damage to the optical fiber 12.

[0010] It is preferable that the four optical fibers 12 are arranged in positions that are rotationally symmetrical to one another in a cross section perpendicular to the tube axis O1 direction of the core material 11. In this embodiment, the optical fibers 12 are arranged at 90° intervals in a cross section perpendicular to the tube axis O1 direction of the core material 11. That is, within the tube wall 11A, the four optical fibers 12 are positioned at equal intervals around the tube axis O1. If there are five or more optical fibers 12, it is preferable that the five or more optical fibers 12 are positioned at equal intervals around the tube axis O1.

[0011] <Core material> The core material 11 in this embodiment is formed by molding a core material composition (A) containing resin (A) into a cylindrical shape and hardening it. The core material 11 is composed of a cylindrical wall 11A. Although the core material 11 in this embodiment is cylindrical, the present invention is not limited thereto. The core material 11 may be polygonal, solid cylindrical, or prismatic. However, from the viewpoint of reducing the weight of the optical fiber-supported resin molded body 10, a cylindrical core material 11 is preferred.

[0012] The outer diameter R of the core material 11 is preferably 20 mm or more and 50 mm or less, and more preferably 30 mm or more and 40 mm or less. If the outer diameter R is above the lower limit, signal interference between optical fibers 12 can be suppressed more effectively. If the outer diameter R is below the upper limit, the core material 11 can more easily follow the displacement of the structure, and the accuracy of measurement by the optical fiber-supported resin molded body 10 can be further improved.

[0013] The thickness of the cylindrical wall 11A is preferably 2.5 mm or more and 10 mm or less, and more preferably 3 mm or more and 5 mm or less. If the thickness of the cylindrical wall 11A is greater than or equal to the lower limit, even if the cylindrical wall 11A is damaged during installation, the optical fiber 12 will not be exposed from the cylindrical wall 11A, and the transmission loss of the optical fiber 12 can be further reduced. If the thickness of the cylindrical wall 11A is less than or equal to the upper limit, the core material 11 will be able to follow the displacement of the structure more easily, and the accuracy of measurements by the optical fiber supported resin molded body 10 can be further improved.

[0014] Resin (A) contains a propylene-based resin. The inclusion of a propylene-based resin in resin (A) improves the accuracy of the measurements. Polypropylene resins are resins consisting solely of propylene units, or polyolefins containing 50 mol% or more of propylene units. Resin (A) may include resins other than polypropylene resins (any resin). Examples of any resin include polyolefin resins (excluding polypropylene), such as polyethylene, polybutene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer. These optional resins may be used individually or in combination of two or more types.

[0015] The polypropylene resin content is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass (i.e., effectively no arbitrary resin) based on the total mass (100% by mass) of resin (A).

[0016] The density of the core material composition (A) (i.e., the density of the cylinder wall 11A) is 0.8 g / cm³. 3 More than 1.0g / cm 3 The following is preferable: 0.85 g / cm³ 3 More than 0.95g / cm 3 The following are more preferable: If the density of the cylinder wall 11A is above the lower limit, the rigidity can be further increased. If the density of the cylinder wall 11A is below the upper limit, molding shrinkage can be suppressed. The density is measured according to ISO 1183-1:2019 "Plastics - Methods for determining the density of non-foamed plastics - Part 1: Immersion method, liquid pycnometer method and titration method".

[0017] The melt flow rate (MFR) of the cylinder wall 11A is preferably, for example, 0.05 g / 10 min. to 4.0 g / 10 min., and more preferably 0.1 g / 10 min. to 3.0 g / 10 min. If the MFR of the cylinder wall 11A is above the lower limit, the core material 11 can be molded more easily. If the MFR of the cylinder wall 11A is below the upper limit, the mechanical strength of the core material 11 can be increased. The MFR (Mass Flow Rate) was measured according to Method A of ISO 1133 "Mass Flow Rate and Volume Flow Rate of Plastics" at 190°C and under a load of 2.16 kg.

[0018] The core material composition (A) may contain components other than the resin (A) (optional component (A)). That is, the core material 11 may contain optional component (A). Examples of optional component (A) include plasticizers, colorants (pigments, dyes), lubricants, ultraviolet absorbers, antioxidants, and other known additives used in polypropylene.

[0019] <Adhesive part> The adhesive portion 16 is a cured product of a base-adhesive polypropylene resin composition. In this embodiment, the presence of the adhesive portion 16 in the optical fiber-supported resin molded body 10 further enhances the adhesive strength between the optical fiber 12 and the cylindrical wall 11A of the core material 11.

[0020] The adhesive portion 16 may be entirely embedded within the cylindrical wall 11A, or a portion of it may be exposed to the outside of the cylindrical wall 11A (i.e., the outer surface of the core material 11). The adhesive portion 16 may cover the entire outer surface (circumferential surface) of the optical fiber 12 (Figure 3), or it may cover only a part of it (Figure 4). That is, the adhesive portion 16 only needs to be located in at least a part of the space between the optical fiber 12 and the cylindrical wall 11A of the core material 11. However, by having the adhesive portion 16 cover the entire outer surface of the optical fiber 12, the adhesive force between the optical fiber 12 and the cylindrical wall 11A of the core material 11 can be further increased, and the optical fiber 12 can be more securely fixed inside the cylindrical wall 11A.

[0021] As shown in Figure 4, when the adhesive portion 16 covers only a part of the optical fiber 12A, in a cross-sectional view, it is preferable that the adhesive portion 16 covers 50% or more of the outer circumference length of the optical fiber 12A, more preferably 70% or more, and even more preferably 90% or more.

[0022] In a cross-section perpendicular to the axis O1, the F / G ratio is the ratio of the area (cross-sectional area) F of the optical fiber 12 to the area (cross-sectional area) G of the adhesive portion 16, and is expressed as a percentage. Preferably, the F / G ratio is 0.1% or more and 6% or less, and more preferably 0.2% or more and 5% or less. If the F / G ratio is above the lower limit, the adhesive strength between the optical fiber 12 and the cylindrical wall 11A of the core material 11 is increased, and the optical fiber 12 can be more securely fixed inside the cylindrical wall 11A. If the F / G ratio is below the upper limit, the workability of stripping the optical fiber is increased. Note that the cross-sectional areas F and G are values ​​obtained through image analysis using an image dimension measuring instrument.

[0023] The base-adhesive polypropylene-based resin composition constituting the adhesive portion 16 (hereinafter sometimes referred to as "adhesive composition (C)") contains base-adhesive polypropylene as a main component. That is, the adhesive portion 16 contains base-adhesive polypropylene as a main component. The adhesive composition (C) contains a resin containing base-adhesive polypropylene (hereinafter sometimes referred to as "resin (C)") and optional components as needed (hereinafter referred to as "optional component (C)").

[0024] The resin (C) contains base-adhesive polypropylene. Imine-modified polypropylene and the like are preferable as the base-adhesive polypropylene. When the resin (C) contains imine-modified polypropylene, the adhesive force between the optical fiber 12 and the cylindrical wall 11A of the core material 11 can be further enhanced.

[0025] The molecular weight of the base-adhesive polypropylene is, for example, 2×10 5 or more and 6×10 5 or less. The molecular weight of the base-adhesive polypropylene is a number average molecular weight determined by GPC (gel permeation chromatography).

[0026] Examples of the base-adhesive polypropylene include ADMER TM IP (imine-modified polypropylene, manufactured by Mitsui Chemicals, Inc., model AT2937) and the like.

[0027] The content of the resin (C) is preferably 90% by mass or more, more preferably 95% by mass or more, and may be 100% by mass, based on the total mass of the adhesive composition (C). The content of the base-adhesive polypropylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass, based on the total mass of the resin (C).

[0028] Examples of the optional component (C) include known additives used for polypropylene, such as plasticizers, colorants (pigments, dyes), lubricants, ultraviolet absorbers, and antioxidants. In addition, examples of the optional component (C) include tackifiers, fillers, thickeners, anti-aging agents, antifoaming agents, and the like. As the optional component (C), acrylic-modified polytetrafluoroethylene is preferred. The adhesive strength can be further enhanced by including acrylic-modified polytetrafluoroethylene in the adhesive portion 16. If the adhesive portion 16 contains acrylic-modified polytetrafluoroethylene, the content of acrylic-modified polytetrafluoroethylene is preferably 1% by mass or more and 10% by mass or less, and more preferably 1.5% by mass or more and 5% by mass or less, based on the total mass of the adhesive portion 16.

[0029] When the adhesive portion 16 was measured with a Fourier transform infrared spectrophotometer, the absorption spectrum due to the methyl group was 1140 cm⁻¹. -1 From 1180cm -1 It appears in the range, and the arithmetic mean of the absorption spectrum is 1168 cm⁻¹. -1 This will be the main focus. 1140cm -1 From 1180cm -1 The peak height of the absorption spectrum in the range 1140 cm² indicates the abundance of methyl groups. -1 From 1180cm -1 The arithmetic mean of the absorption spectra in the range is 1168 cm⁻¹. -1 This will be the main focus. In this paper, we report the measurement of 1168 cm⁻¹ using a Fourier transform infrared spectrophotometer. -1 Let the height of the absorption spectrum (the peak height of the absorbance) be defined as the peak height α. When the adhesive portion 16 was measured with a Fourier transform infrared spectrophotometer, the absorption spectrum due to the imine group was 2090 cm⁻¹. -1 From 2150cm -1 The range, or 2230cm -1 From 2280cm -1 It appears within the range of 2090cm. -1 From 2150cm -1 The range, or 2230cm -1 From 2280cm -1 The absorption spectrum in the range of 2090 cm² indicates the abundance of the imine group. -1 From 2150cm -1 The range, or 2230cm -1 From 2280cm -1 The arithmetic mean of the absorption spectra in the range is 2120 cm⁻¹.-1 , 2260cm -1 This will be the main focus. In this paper, we present the 2120 cm² measured with a Fourier transform infrared spectrophotometer. -1 , 2260cm -1 Let the heights of the absorption spectra be the peak heights β and γ, respectively.

[0030] In the adhesive portion 16, the ratio of peak height β to peak height α (β / α ratio) is 0.6 or more and 0.9 or less, preferably 0.65 or more and 0.85 or less, and more preferably 0.7 or more and 0.8 or less. The ratio of peak height γ to peak height α (γ / α ratio) is 0.20 or more and 0.27 or less, preferably 0.22 or more and 0.26 or less, and more preferably 0.23 or more and 0.25 or less. If the β / α ratio and γ / α ratio are within the above ranges, the affinity with both the optical fiber 12 and the core material 11 will be further increased, and the adhesive strength between the optical fiber 12 and the cylindrical wall 11A of the core material 11 can be further enhanced.

[0031] The density of the adhesive portion 16 is 0.8 g / cm³. 3 More than 1.0g / cm 3 The following is preferable: 0.85 g / cm³ 3 More than 0.95g / cm 3 The following are more preferable: If the density of the adhesive portion 16 is above the lower limit, the rigidity can be further increased. If the density of the adhesive portion 16 is below the upper limit, the adhesive strength can be further increased. The density of the adhesive portion 16 may be the same as or different from the density of the cylindrical wall 11A.

[0032] The MFR of the adhesive portion 16 is preferably, for example, 0.5 g / 10 min. to 4 g / 10 min., more preferably 0.6 g / 10 min. to 3.9 g / 10 min., and even more preferably 0.7 g / 10 min. to 3.8 g / 10 min. If the MFR of the adhesive portion 16 is above the lower limit, the fluidity is good, and the adhesive strength between the optical fiber 12 and the cylindrical wall 11A of the core material 11 can be further increased. If the MFR of the adhesive portion 16 is below the upper limit, the moldability is good, and stable manufacturing is possible. The MFR of the adhesive portion 16 may be the same as or different from the MFR of the cylindrical wall 11A. The MFR of the adhesive portion 16 can be adjusted by the combination of the composition of the resin (C), the type of optional component (C), and the amount of each component.

[0033] The softening point of the adhesive portion 16 is preferably, for example, 30°C to 115°C, more preferably 35°C to 110°C, and even more preferably 40°C to 105°C. If the softening point of the adhesive portion 16 is above the lower limit, the handling properties are excellent, and the adhesive strength between the optical fiber 12 and the core material 11 can be further increased. If the softening point of the adhesive portion 16 is below the upper limit, the moldability is good, and the adhesive strength between the optical fiber 12 and the cylindrical wall 11A of the core material 11 can be further increased. The softening point of the adhesive portion 16 is the Vicat softening point measured according to ISO 306. The softening point of the adhesive portion 16 can be adjusted by the combination of the composition of the resin (C), the type of optional component (C), and the amount added.

[0034] The dimensional shrinkage rate of the adhesive portion 16 is preferably 5.5% or less, more preferably 5.4% or less, and even more preferably 5.3% or less. If the dimensional shrinkage rate of the adhesive portion 16 is less than or equal to the above values, the stress during bonding can be kept low, thereby increasing the adhesive strength between the optical fiber 12 and the core material 11. The dimensional shrinkage rate of the adhesive portion 16 is a value calculated by taking the cube root of the volume shrinkage rate measured by the constant pressure temperature change mode of PVT measurement, and is calculated using the measurement results of volume shrinkage at a pressure of 10 MPa from 180°C to 30°C. An example of such a PVT measuring device is the "PVT Test System" manufactured by Toyo Seiki Seisakusho. The dimensional shrinkage rate of the adhesive portion 16 can be adjusted by the combination of the composition of the resin (C), the type of optional component (C), and the amount added.

[0035] <Optical fiber> The optical fiber 12 may be a bare fiber, a fiber strand, or a fiber core. A bare fiber is a fiber consisting of a core and at least one cladding layer surrounding the core, and is composed solely of glass. A fiber strand is a fiber in which the outer circumference of a bare fiber is coated with an ultraviolet-curing resin. A fiber core is a fiber in which the outer circumference of the fiber strands is coated with a thermoplastic resin (a fiber having a thermoplastic resin coating layer). As shown in Figure 5, the optical fiber 12 of this embodiment has an optical fiber strand 13 and a coating resin layer 14 that covers the circumferential surface of the optical fiber strand 13. The optical fiber 12 in Figure 5 is a so-called fiber core.

[0036] When the optical fiber-supported resin molded body 10 is used as an optical fiber for strain measurement or an optical fiber for temperature measurement, the type of optical fiber 12 is not particularly limited and can be selected according to the strain measurement method, the temperature measurement method, the type of scattered light used during measurement, etc. For example, it is preferable to use at least one type of optical fiber selected from the group consisting of single-mode optical fiber, multi-mode optical fiber, and polarization-maintaining optical fiber as the optical fiber for strain measurement or the optical fiber for temperature measurement. The optical fiber used for strain measurement and the optical fiber used for temperature measurement may be of the same type or different types.

[0037] The optical fiber-supported resin molded body 10 of this embodiment can have one or more optical fibers as strain measuring optical fibers or temperature measuring optical fibers, depending on the measurement method, etc. Therefore, for example, two or more optical fibers of different types or the same type can be used as strain measuring optical fibers. The same applies to the temperature measuring optical fiber.

[0038] For strain measurement, single-mode optical fibers are preferred. Single-mode optical fibers are preferred because, when performing measurements, they can preferably use Brillouin scattered light, Rayleigh scattered light, etc., as scattered light, and sharp peaks can be obtained. For temperature measurement, multimode optical fibers are preferred. Multimode optical fibers are preferred because they can preferably use Raman scattered light or the like as scattered light, and can obtain high peak intensity. In this way, by selecting an optical fiber 12 suitable for the scattered light used for measurement, strain and temperature can be measured with high accuracy.

[0039] The optical fiber strand 13 of this embodiment has, for example, a core 13A, a cladding 13B, and an ultraviolet-curing resin (not shown). The present invention is not limited thereto, and the optical fiber strand 13 does not have to have cladding 13B. However, it is preferable that the optical fiber strand 13 has a core 13A and cladding 13B. By having a core 13A and cladding 13B, the optical fiber strand 13 can be subjected to discontinuous pump light such as laser light to the core 13A, generating scattered light originating from core strain, temperature, etc., such as Brillouin scattering and Raman scattering, thereby improving measurement accuracy.

[0040] Examples of materials for core 13A include quartz glass. The material of clad 13B is the same as the material of core 13A. The materials of core 13A and cladding 13B may be the same or different.

[0041] The coating resin layer 14 is a cured product of an adhesive resin composition (coating composition) (B) containing resin (B). Resin (B) is a polyimide resin. Polyimide resins mainly consist of polyimide. The polyimide content is preferably 70% by mass or more, preferably 90% by mass or more, and more preferably 100% by mass, based on the total mass of resin (B). Furthermore, the coating resin layer 14 may be a multilayer structure consisting of two or more layers. If the coating resin layer 14 is a multilayer structure, at least the outermost layer is a cured product of the resin composition (B). Resin (B) may be used alone or in combination of two or more types.

[0042] The content of resin (B) relative to the total mass of coating composition (B) is preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass.

[0043] The coating composition (B) may contain components other than the resin (B) (optional component (B)). Optional component (B) is the same as optional component (A).

[0044] The surface (outer surface) of the coating resin layer 14 may be subjected to a roughening treatment. The method of surface roughening is not particularly limited and includes, for example, mechanical methods such as sandblasting, physical methods such as corona treatment, and chemical methods such as primer treatment and etching.

[0045] The outer diameter r of the optical fiber strand 13 is preferably 125 to 2000 μm, and more preferably 150 to 1000 μm. If the outer diameter r is above the lower limit, it becomes less likely to break when a load is applied, thereby increasing productivity and durability. If the outer diameter r of the optical fiber strand 13 is below the upper limit, the peeling of the coating resin can be performed more easily when connecting optical fiber-supported resin molded bodies 10 together or when connecting the optical fiber 12 to a measuring instrument.

[0046] The thickness t14 of the coating resin layer 14 is preferably, for example, 5 to 950 μm, more preferably 10 to 900 μm, and even more preferably 15 to 850 μm. If the thickness t14 is above the lower limit, the mechanical strength of the optical fiber 12 can be further increased. If the thickness t14 is below the upper limit, the peeling of the coating resin during connection can be made easier.

[0047] (Method for manufacturing a resin molded body with optical fibers supported) A method for manufacturing a resin molded body supporting optical fibers will be explained with an example. The manufacturing method of the optical fiber-supported resin molded body of this embodiment includes the step of providing an optical fiber 12, which has a coating resin layer 14 pre-formed on it, inside the cylindrical wall 11A.

[0048] One method for providing an optical fiber 12 within the cylindrical wall 11A is to supply the optical fiber 12 to an extrusion molding machine, extrude the molten core material composition (A) and adhesive composition (C) into a long cylindrical shape, and then cool the cylindrical molded product while taking it back to harden the core material composition (A) and adhesive composition (C) to obtain an optical fiber-supported resin molded body (integral molding method). When supplying the optical fiber 12 to the extrusion molding machine, the adhesive composition is supplied to the mold so that the adhesive composition is located on the outer surface of the optical fiber 12, thereby creating an adhesive portion 16 between the optical fiber 12 and the core material 11. In the integral molding method, it is preferable that the adhesive portion 16 is not exposed on the outer surface of the core material 11.

[0049] Alternatively, optical fibers 12 may be provided inside the cylinder wall 11A by a post-coating method. The post-coating method is described below. A core material 11 is prepared in advance. A groove is formed on the outer surface of this core material 11, extending toward the inner surface. The number of grooves is the number of optical fibers 12 to be provided inside the cylinder wall 11A. Note that a core material 11 with grooves may be manufactured when the core material 11 is produced. The optical fiber 12 is fitted into the grooves on the outer surface of the core material 11. Next, the adhesive composition (C) is filled into the recesses through the openings of the grooves. Then, the adhesive composition (C) filled into the recesses is cured to provide the optical fiber 12 inside the cylindrical wall 11A. In the post-coating method, the adhesive portion 16 is exposed on the outer surface of the core material 11. In the post-coating method, after filling the recesses with the adhesive composition, the recesses may be sealed with a resin composition (for example, core material composition (A)). By sealing the recesses with a resin composition, the adhesive portion 16 is not exposed on the outer surface of the core material 11. In this way, a resin molded body 10 supporting optical fibers is obtained.

[0050] According to the optical fiber-supported resin molded body of this embodiment, at least a portion of the outer surface of the optical fiber has a specific adhesive portion, and the optical fiber and the core material are bonded together at the adhesive portion. As a result, the optical fiber is less likely to peel off from the core material. In addition, because it has an adhesive portion with a specific composition, the adhesion between the optical fiber and the core material is improved, and displacement of the optical fiber within the core material during manufacturing can be prevented. Therefore, according to the present invention, the optical fiber can be more securely fixed within the core material.

[0051] (Other embodiments) The present invention is not limited to the embodiments described above. The optical fiber-supported resin molded body 10 of the present invention may be, for example, the optical fiber-supported resin molded body 20 shown in Figure 6. The optical fiber-supported resin molded body 20 includes a cylindrical core material 21 and an optical fiber 22 that is spirally embedded within the cylindrical wall 21A of the core material 21 at an inclination angle of more than 0 degrees and less than 90 degrees from the axial direction O2 of the core material 21 toward the circumferential direction. The optical fiber-supported resin molded body 20 differs from the optical fiber-supported resin molded body 10 only in that the optical fiber 22 forms a spiral around the axis O2 of the core material 21.

[0052] The helical pitch P of the optical fiber 22 is preferably 10 mm or more and 600 mm or less, more preferably 50 mm or more and 500 mm or less, and even more preferably 100 mm or more and 200 mm or less. If the helical pitch P is above the above upper limit, the measurement accuracy can be improved without making the length of the optical fiber 22 excessively long. If the helical pitch P is below the above upper limit, the measurement accuracy can be further improved. [Examples]

[0053] The present invention will be described in more detail below, but the present invention is not limited to the following embodiments.

[0054] (Materials used) <Core material composition (A)> Composition A-1: ​​Polypropylene, 0.91 g / cm³ 3 MFR = 0.5g / 10min.

[0055] <Core material composition (A')> Comparative product of core material composition • Composition A'-1: Low-density polyethylene, 0.9 g / cm³ 3 MFR = 2.0g / 10min.

[0056] <Coating composition (B)> Composition B-1: Polyimide, 1.4 g / cm³ 3 .

[0057] <Coated composition (B')> Comparative product of coated composition Composition B'-1: Nylon elastomer, 1.0 g / cm³ 3 .

[0058] <Adhesive composition (C)> Composition C-1: Imine-modified polypropylene (product name "Admer™IP AT2937", manufactured by Mitsui Chemicals, Inc.). Peak height α = 0.267, peak height β = 0.215, peak height γ = 0.064. Composition C-2: Imine-modified polypropylene (product name "Admer™IP AT2937", manufactured by Mitsui Chemicals, Inc.) with 2.0% by mass of acrylic-modified polytetrafluoroethylene (product name "Metablen", manufactured by Mitsubishi Chemical Corporation). Peak height α = 0.267, peak height β = 0.215, peak height γ = 0.064. Composition C-3: Imine-modified polypropylene (product name "Admer™IP AT2937", manufactured by Mitsui Chemicals, Inc.) with 9.0% by mass of acrylic-modified polytetrafluoroethylene (product name "Metablen", manufactured by Mitsubishi Chemical Corporation). Peak height α = 0.267, peak height β = 0.215, peak height γ = 0.064. Composition C-4: Imine-modified polypropylene (product name "Admer™IP AT2937", manufactured by Mitsui Chemicals, Inc.) with 15.0% by mass of acrylic-modified polytetrafluoroethylene (product name "Metablen", manufactured by Mitsubishi Chemical Corporation). Peak height α = 0.267, peak height β = 0.215, peak height γ = 0.064.

[0059] <Adhesive composition (C')> Comparative product of adhesive composition Composition C'-1: Acid-modified olefin (product name "QF500"), manufactured by Mitsui Chemicals, Inc. Peak height α = 0.207, peak height β = 0.034, peak height γ = 0.033. • Composition C'-2: Acid-modified olefin (product name "QB550"), manufactured by Mitsui Chemicals, Inc. Peak height α = 0.263, peak height β = 0.039, peak height γ = 0.039. • Composition C'-3: Acid-modified olefin (product name "SF731"), manufactured by Mitsui Chemicals, Inc. Peak height α = 0.117, peak height β = 0.033, peak height γ = 0.035. • Composition C'-4: Acid-modified olefin (product name "P674V"), manufactured by Mitsubishi Chemical Corporation. Peak height α = 0.335, peak height β = 0.036, peak height γ = 0.038. • Composition C'-5: Polypropylene (product name "B241"), manufactured by Prime Polymer. Peak height α = 0.604, peak height β = 0.030, peak height γ = 0.045.

[0060] <Bare Fiber> • Bare fiber: PYROCOAT, manufactured by Furukawa Electric Co., Ltd.

[0061] (Evaluation method) <Optical fiber conductivity> For each example of a resin molded body supporting an optical fiber, a red light checker was used to input red light into the optical fiber and measure the optical fiber conductivity based on the amount of light leakage. The measurement results were evaluated according to the evaluation criteria below.

[0062] ≪Evaluation Criteria≫ ○: No red light was observed in the middle of the optical fiber, but red light was observed at the end of the optical fiber. ×: Red light can be seen midway through the optical fiber, but not at the end of the optical fiber.

[0063] <Adhesiveness> For each example of a resin molded body supporting an optical fiber, the adhesiveness was measured using a tensile testing machine, observing the optical fiber failure pattern when the optical fiber was pulled out at 23°C and a tensile speed of 20 mm / min. The measurement results were evaluated according to the following evaluation criteria.

[0064] ≪Evaluation Criteria≫ ○: The glass strands of the optical fiber break. △: The optical fiber does not break, but the adhesive material is damaged. ×: The glass strands of the optical fiber do not break, but the interface between the adhesive and the optical fiber peels off and the fiber is pulled out.

[0065] <Position misalignment> For each example of a resin molded body supporting optical fibers, the positional displacement was measured using an image dimension measuring instrument. The measurement results were evaluated according to the evaluation criteria below.

[0066] ≪Evaluation Criteria≫ ○: The optical fiber is contained within the adhesive composition. ×: The optical fiber protrudes from the adhesive composition.

[0067] (Examples 1-5, Comparative Examples 1-6) According to Table 1, bare fibers were coated with a coating composition (thickness: 150 μm) to obtain the optical fibers for each example. According to Table 1, the optical fibers, core material composition, and adhesive composition for each example were supplied to an extrusion molding machine and extruded into a cylindrical shape to obtain an optical fiber-supported resin molded body with an outer diameter R=34 mm and a cylindrical wall thickness=4 mm. For the obtained optical fiber-supported resin molded body, the β / α ratio and F / G ratio of the adhesive portion were determined, and the adhesiveness and positional misalignment were evaluated. The results are shown in the table.

[0068] [Table 1]

[0069] As shown in Table 1, Examples 1 to 4 to which the present invention was applied showed "○" for adhesion and "○" for misalignment, while Example 5 showed "△" for adhesion and "○" for misalignment. Comparative Example 1, which used compositions A'-1 and B'-1 instead of compositions A-1 and B-1, showed poor optical fiber conductivity and adhesion. Comparative Examples 2-6, which used compositions C'-1 to C'-5 instead of composition C-1, showed poor adhesion ("×"). [Explanation of Symbols]

[0070] 10, 20 Fiber optic supported resin molded body 11 Core material 11A Cylinder wall 12, 12A optical fiber 13 Optical fiber strands 14. Coating resin layer 16 Adhesive part O1, O2 axis

Claims

1. It comprises a long core material, one or more optical fibers located within the core material and extending in the axial direction of the core material, and an adhesive portion located in at least a portion between the core material and the optical fibers, The aforementioned core material contains a polypropylene resin, The optical fiber has a coating resin layer of polyimide resin, The adhesive portion is a molded resin body supporting optical fibers, which is a cured product of a base-adhesive polypropylene resin composition.

2. The optical fiber-supported resin molded article according to claim 1, wherein the base-adhering polypropylene resin composition comprises imine-modified polypropylene.

3. The adhesive portion is measured at 1168 cm⁻¹ using a Fourier transform infrared spectrophotometer. －１ 2120 cm² relative to the peak height α of absorbance at －１ The optical fiber-supported resin molded article according to claim 1, wherein the ratio of the peak height β of the absorbance in (β / α) is 0.6 or more and 0.9 or less.

4. The adhesive portion is measured at 1168 cm⁻¹ using a Fourier transform infrared spectrophotometer. －１ 2160 cm² relative to the peak height α of absorbance at [location] －１ The optical fiber-supported resin molded article according to claim 1, wherein the ratio of the peak height γ of the absorbance in (γ / α) is 0.20 or more and 0.27 or less.

5. The optical fiber-supported resin molded article according to claim 1, wherein, in a cross section perpendicular to the axial direction, the ratio of the cross-sectional area F of the optical fiber to the cross-sectional area G of the adhesive portion is 0.1% or more and 6% or less.

6. The adhesive portion contains acrylic-modified polytetrafluoroethylene, as described in claim 1, for the optical fiber-supported resin molded article.

7. The optical fiber supported resin molded article according to claim 6, wherein the content of the acrylic-modified polytetrafluoroethylene is 1% by mass or more and 16% by mass or less based on the total mass of the adhesive portion.

8. The optical fiber-supported resin molded article according to claim 1, wherein the melt flow rate (MFR) of the adhesive portion is 0.05 g / 10 min. to 4.0 g / 10 min., measured in accordance with ISO 1133 Method A at 230°C and a load of 2.16 kg.

9. The base-adhesive polypropylene resin composition, the optical fiber, and the core material composition containing the polypropylene resin are supplied to an extrusion molding machine. A method for producing an optical fiber-supported resin molded article according to any one of claims 1 to 8, comprising the steps of melting the core material composition and the base-adhesive polypropylene resin composition, extruding them together with the optical fiber in a long length, and cooling to obtain the optical fiber-supported resin molded article.

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