Optical fiber supported molded body

Abstract

To make it easier to identify the position of the optical fiber in a molded body supporting an optical fiber. [Solution] The device comprises a long core material and one or more optical fibers located within the core material and extending in the axial direction of the core material, wherein the core material has a covering portion that covers the optical fibers from the outer surface of the core material, and the covering portion is semi-transparent. The core material has a core material body having one or more grooves extending in the axial direction on its outer surface, and the covering portion that fills the grooves and covers the openings of the grooves, and preferably the outer surface of the core material has exposed portions in the circumferential direction where the covering portion is not present.

Description

[Technical Field]

[0001] The present invention relates to an optical fiber-carrying molded article. [Background Art]

[0002] There is an optical fiber-carrying molded article having a long core material (e.g., a resin pipe) and an optical fiber embedded linearly or spirally in the core material so as to extend in the axial direction. The optical fiber-carrying molded article can constantly monitor changes in bending, elongation, torsional strain, pressure change, and temperature change that occur in the core material, from frequency changes or phase changes of Rayleigh scattering in the optical fiber. When connecting the optical fiber-carrying molded article to a measuring instrument, it is necessary to take out the optical fiber from the core material at an end portion of the carrying molded article. A method has been proposed in which an end portion of the optical fiber-carrying molded article is heated to melt a portion covering the optical fiber, and the optical fiber is taken out from the core material (Patent Document 1). [Prior Art Literature] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2022-115167 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, there has been a problem that visually, it is difficult to identify the position of the optical fiber from the outer surface of the optical fiber-carrying molded article. Accordingly, an object of the present invention is to provide an optical fiber-carrying molded article that allows easy identification of the position of an optical fiber. [Means for Solving the Problem]

[0005] The present invention has the following aspects. <1> comprising a long core material, and one or more optical fibers positioned inside the core material and extending in the axial direction of the core material, The core material has a covering portion that covers the optical fiber from the outer surface of the core material, The aforementioned covering portion is a semi-transparent, optical fiber-supported molded body. <2> The core material comprises a core material body having one or more grooves extending in the axial direction on its outer surface, and a covering portion that fills the grooves and covers the openings of the grooves. The outer surface of the core material has an exposed portion in the circumferential direction where the covering portion is absent. <1> A molded fiber optic support as described above. <3> The aforementioned coating has a total light transmittance of 35% or more as specified in JIS K7361-1. <1> or <2> A molded fiber optic support as described above. <4> The aforementioned coating has a haze value of 98% or less as specified in JIS K7136. <1> ~ <3> A molded fiber-supported body as described in any of the following. <5> The thickness of the coating on the optical fiber is 0.1 to 2.5 mm. <1> ~ <4> A molded fiber-supported body as described in any of the following. <6> The coating contains polyethylene, and the degree of crystallinity of the coating, as measured by DSC analysis as specified in JIS K7122, is 27-67%. <1> ~ <5> A molded fiber-supported body as described in any of the following. [Effects of the Invention]

[0006] According to the optical fiber-supported molded body of the present invention, the optical fiber can be more securely fixed within the core material. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing a molded fiber-supported body according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] This is a magnified view of region s in Figure 2. [Figure 4] This is a cross-sectional view showing an example of an optical fiber. [Figure 5] It is a perspective view showing an optical fiber-carrying molded article according to an embodiment of the present invention. [Figure 6] It is a schematic diagram showing an example of a manufacturing apparatus for an optical fiber-carrying molded article. [Figure 7] It is a schematic diagram showing an example of a manufacturing apparatus for an optical fiber-carrying molded article. MODE FOR CARRYING OUT THE INVENTION

[0008] In the present specification and claims, the symbol "~" indicating a numerical range means that the numerical values described before and after it are included as the lower limit value and the upper limit value.

[0009] (Optical Fiber-Carrying Molded Article) The optical fiber-carrying molded article of the present invention includes a core material and one or two or more optical fibers extending in the axial direction of the core material. Hereinafter, an embodiment of the optical fiber-carrying molded article of the present invention will be described for illustration. The optical fiber-carrying molded article 10 in Fig. 1 is a cylindrical long resin tube. The optical fiber-carrying molded article 10 includes a cylindrical core material 11 and an optical fiber 12 extending in a cylindrical wall 11A of the core material 11 in the direction of an axis (tube axis) O1 of the core material 11. In the present embodiment, the core material 11 includes: a core material main body 111 having one or more recessed grooves 110 extending in the axial direction on the outer surface thereof; and a covering portion 112 that fills the inside of the recessed groove 110 and covers the opening surface of the recessed groove 110. The outer surface of the core material 11 has an exposed portion 23 where the covering portion 112 does not exist in the circumferential direction.

[0010] As shown in Figs. 1 to 3, the core material main body 111 has the recessed groove 110 extending in the direction of the axis O1 on the outer surface thereof. In the present embodiment, the core material main body 111 has four recessed grooves 110. The recessed groove 110 is recessed inward from the outer surface of the core material main body 111. That is, the recessed groove 110 is open to the outer surface of the core material main body 111. The four recessed grooves 110 are parallel to each other and along the axis O1. In the present embodiment, the four optical fibers 12 are substantially parallel in a side view.

[0011] The optical fiber 12 is located within the groove 110. In this embodiment, one optical fiber 12 is located within one groove 110. The covering portion 112 has a filling portion 112a that fills the recessed portion 110 and a raised portion 112b that covers the opening surface of the recessed portion 110. Between any covering portion 112 and any other covering portion 112 adjacent to it, there is an exposed portion 23 which is a region without a raised portion 112b (a region where the core material 11 is exposed). That is, the optical fiber supported molded body 10 has an exposed portion 23 on its outer surface in which there is no covering portion 112 (raised portion 112b) in the circumferential direction.

[0012] In this embodiment, the optical fiber-supported molded body 10 has four optical fibers 12 inside the cylindrical wall 11A. 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 direction of the tube axis O1 in the cylindrical wall 11A of the core material 11. In this embodiment, the optical fibers 12 are located at 90° intervals in a cross section perpendicular to the direction of the tube axis O1 of the core material 11. That is, within the cylindrical wall 11A, the four optical fibers 12 are located at equal intervals around the tube axis O1.

[0013] 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. When there are two or more optical fibers 12, bending displacement can be detected more effectively. When 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. When the number of optical fibers 12 is below the above upper limit, the mechanical strength of the core material 11 can be further increased. If there are two or more optical fibers 12, it is preferable that the two or more optical fibers 12 are positioned at equal intervals around the tube axis O1.

[0014] The length of the optical fiber-supported molded body 10 is not particularly limited, and can be, for example, 1m to 1000m.

[0015] <Core material> The core material 11 has a core material body 111 and a covering portion 112. In this embodiment, the core material 11 is cylindrical. However, the core material 11 may be polygonal tubular, or a solid cylindrical or polygonal prism.

[0016] The outer diameter R1 of the core material 11 is preferably 20 to 50 mm, and more preferably 30 to 40 mm. If the outer diameter R1 is greater than or equal to the lower limit, signal interference between optical fibers 12 can be suppressed more effectively. If the outer diameter R1 is less than or equal to the upper limit, the core material 11 can more easily follow the displacement of the structure, thereby improving the accuracy of measurements by the optical fiber supported molded body 10.

[0017] The inner diameter R2 of the core material 11 is preferably 10 to 45 mm, and more preferably 30 to 40 mm. If the inner diameter R2 is above the lower limit, further weight reduction can be achieved. If the inner diameter R2 is below the upper limit, the strength of the core material 11 can be further increased.

[0018] The thickness T of the cylindrical wall 11A is preferably 2.5 to 10 mm, and more preferably 3 to 5 mm. If the thickness T 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 T 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 molded body 10 can be further improved.

[0019] ≪Core material≫ The color tone of the core material body 111 is not particularly limited and will be determined appropriately considering the application and design of the optical fiber-supported molded body. The core material body 111 may be transparent, semi-transparent, or opaque. The color tone and total light transmittance of the core material body 111 can be adjusted by the composition (the combination of the type of resin (A), the type of optional component (A), and the amount of each component in the resin composition (A) described later).

[0020] Examples of materials for the core body 111 include resin, metal, glass, and ceramics. Among these, resin is preferred because it is lightweight and easy to process. Examples of resin core materials include cured products of resin composition (A) containing resin (A).

[0021] Examples of resin (A) include polyolefin resins such as polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer. Examples of polyethylene include low-density polyethylene (LDPE, density: 910 kg / m³). 3 More than 930kg / m 3 (less than), medium-density polyethylene (MDPE, density: 930 kg / m³) 3 More than 942kg / m 3 (less than), high-density polyethylene (HDPE, density: 942 kg / m³) 3 The above are examples. Resin (A) may be used alone or in combination of two or more types.

[0022] As resin (A), polyethylene is preferred, MDPE and HDPE are more preferred, and a mixture of MDPE and HDPE is even more preferred. When resin (A) is a mixture of MDPE and HDPE, the mass ratio of MDPE to HDPE (MDPE / HDPE) (M / H ratio) is preferably 40 / 60 to 90 / 10, and more preferably 60 / 40 to 90 / 10. If the M / H ratio is above the lower limit, shrinkage during molding is reduced, and the accuracy of the measurement can be further improved. If the M / H ratio is below the upper limit, the dimensions of the core material 11 can be made more stable.

[0023] If resin (A) contains resins other than polyolefins, the content of resins other than polyolefins relative to the total mass (100% by mass) of resin (A) is preferably 20% by mass or less, more preferably 10% by mass or less, and may even be 0% by mass.

[0024] The content of resin (A) relative to the total mass (100% by mass) of resin composition (A) is preferably 80% by mass or more, more preferably 90% by mass or more, and may also be 100% by mass.

[0025] The density of the resin composition (A) (i.e., the density of the core material body 111) is 0.920 to 0.960 g / cm³. 3 Preferably, 0.930~0.950 g / cm³ 3 This is more preferable. If the density of the core material body 111 is above the lower limit, the rigidity can be further increased. If the density of the core material body 111 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".

[0026] The melt flow rate (MFR) of the core material body 111 (i.e., the MFR of the resin composition (A)) is preferably, for example, 0.1 to 1.3 g / 10 min., and more preferably 0.2 to 0.8 g / 10 min. If the MFR of the core material body 111 is above the lower limit, the core material body 111 can be molded more easily. If the MFR of the core material body 111 is below the upper limit, the mechanical strength of the core material body 111 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.

[0027] The resin composition (A) may contain components other than 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 polyolefin resins.

[0028] The groove 110 narrows in width from the outer surface of the core material 11 inwards (in the direction of the axis O1). That is, the groove 110 has a narrowing section in which the width decreases from the outer surface inwards.

[0029] The cross-sectional shape of the recessed ridge 110 may or may not have a narrowed width section. The cross-sectional shape of the recessed ridge 110 may be V-shaped, U-shaped, or a rectangle with the same width from the opening to the bottom. From the viewpoint of ease of processing and ease of the arrangement process described later, the cross-sectional shape of the recessed ridge 110 is preferably a shape with a narrowed width section (e.g., V-shaped, U-shaped, etc.). For example, the recessed ridge 110 may deepen inward from the outer surface of the core material 11 with the same width, and then become a narrowed width section. Alternatively, the recessed ridge 110 may become narrower in width from the outer surface inward, and then deepen with the same width.

[0030] The opening width (maximum width in this embodiment) W of the groove 110 is preferably 0.9 to 7.3 mm, more preferably 1.0 to 6.0 mm, and even more preferably 3.0 to 5.0 mm. If the opening width W is greater than or equal to the lower limit, the optical fiber 12 can be more reliably protected when inserting it into an excavation hole in the object to be measured (structure, etc.) during construction. When constructing the optical fiber carrying molded body 10, it is necessary to cut the end of the optical fiber carrying molded body 10 to expose the optical fiber 12. If the opening width W is less than or equal to the upper limit, the covering portion 112 can be easily peeled off from the core material body 111, and the workability of connecting the optical fiber 12 to the measuring instrument can be further improved. In this embodiment, the opening width W is the width of the opening surface of the groove 110. The width of the opening surface is the distance between the contact points P-P' between the tangent Q (Figure 3) and the outer surface of the core material 11 when a tangent Q is drawn on the opening surface.

[0031] The depth D of the groove 110 is preferably 0.9 to 2.7 mm, more preferably 1.0 to 2.0 mm, and even more preferably 1.1 to 1.4 mm. If the depth D is greater than or equal to the lower limit, the positional accuracy of the optical fiber 12 can be further improved. If the depth D is less than or equal to the upper limit, the strength of the core material body 111 can be further improved. The depth D is the distance from the tangent Q to the bottom of the concave groove 110.

[0032] <Covered part> The covering portion 112 has a filling portion 112a and a raised portion 112b. The filling portion 112a and the raised portion 112b are a single molded body. The filling portion 112a fills the recessed portion 110. The raised portion 112b covers the opening surface of the recessed portion 110 and is raised on the opening surface of the recessed portion 110. Because the covering portion 112 has the raised portion 112b, it can be visually confirmed that the inside of the recessed portion 110 is filled with the filling portion 112a and that there are no voids inside the recessed portion 110. The covering portion 112 only needs to cover the optical fiber 12 to the extent that it is not exposed. For this reason, the covering portion 112 may consist only of the filling portion 112a.

[0033] The color tone of the covering portion 112 is not particularly limited and will be determined appropriately considering the application and design of the optical fiber-supported molded body. The covering portion 112 is transparent or translucent. When the covering portion 112 is transparent or translucent, the position of the optical fiber 12 within the groove 110 can be easily identified by visual inspection. In particular, it is preferable that the covering portion 112 is translucent. When the covering portion 112 is translucent, the boundary between the covering portion 112 and the core material body 111 can be easily identified by visual inspection. "Transparent" means that the total light transmittance is 100%. "Semi-transparent" means that the total light transmittance is less than 100%, and that it can transmit visible light to the extent that the position of the optical fiber 12 within the groove 110 can be seen. The color tone and total light transmittance of the coated portion 112 can be adjusted by the composition (for example, the combination of the type of resin (C), the type and amount of optional component (C) in the resin composition (C) described later), thickness, etc.

[0034] The total light transmittance of the covering portion 112, as defined in JIS K7361-1, is preferably 35% or more, more preferably 45% or more, even more preferably 70% or more, and may be 100%. If the total light transmittance of the covering portion 112 is above the above lower limit, the optical fiber 12 inside the groove 110 can be more easily identified from the outside.

[0035] In the coating portion 112, the haze value specified in JIS K7136 is preferably 98% or less, more preferably 90% or less, and even more preferably 80% or less. When the haze value of the coating portion 112 is below the above upper limit, the optical fiber 12 inside the groove 110 can be more easily identified from the outside. The lower limit of the haze value of the coated portion 112 is not particularly limited, but is substantially 30% or more.

[0036] Examples of materials for the covering portion 112 include resin, metal, glass, and ceramics. Among these, resin is preferred because it is lightweight and easy to process. Examples of the resin coating portion 112 include a cured product of a resin composition (C) containing resin (C). Examples of resin (C) include thermoplastic resins and energy-ray curable resins. Examples of thermoplastic resins include polyolefins, polyesters, polyamides, polyimides, and fluororesins. Examples of energy-ray curable resins include phenolic resins and epoxy resins. Among these, thermoplastic resins are preferred as resin (C), polyolefins are more preferred, and polyethylene is even more preferred.

[0037] The content of resin (C) relative to the total mass (100% by mass) of resin composition (C) is preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass.

[0038] The resin composition (C) may contain components other than resin (C) (optional component (C)). Optional component (C) is the same as optional component (A).

[0039] If the coating portion 112 contains polyethylene, the degree of crystallinity of the coating portion 112, as measured by DSC analysis as specified in JIS K7122, is preferably 27-67%, more preferably 30-55%, and even more preferably 33-45%. If the degree of crystallinity of the coating portion 112 is above the lower limit, the strength can be increased. If the degree of crystallinity of the coating portion 112 is below the upper limit, the visibility of the optical fiber can be increased.

[0040] The MFR of the coating portion 112 (i.e., the MFR of the resin composition (C)) is preferably, for example, 0.1 to 3.7 g / 10 min., and more preferably 0.8 to 2.0 g / 10 min. If the MFR of the coating portion 112 is above the lower limit, the coating portion 112 can be molded more easily. If the MFR of the coating portion 112 is below the upper limit, the mechanical strength of the coating portion 112 can be increased.

[0041] The MFR of the covering portion 112 may be the same as or different from the MFR of the core material body 111. From the viewpoint of easily peeling the covering portion 112 from the core material body 111 when exposing the optical fiber 12, it is preferable that the MFR of the covering portion 112 and the MFR of the core material body 111 be different.

[0042] The thickness T112 of the coating portion 112 on the optical fiber 12 is preferably 0.1 to 2.5 mm, more preferably 0.4 to 2.0 mm, and even more preferably 0.5 to 1.5 mm. If the thickness T112 is greater than or equal to the lower limit, the optical fiber 12 can be more reliably protected from external impacts. If the thickness T112 is less than or equal to the upper limit, the optical fiber can be removed more easily.

[0043] The width w of the convex portion 112b is preferably equal to or wider than the opening width W of the concave portion 110, and more preferably wider than the opening width W. By having a width w equal to or wider than the opening width W, the adhesion between the core material 11 and the optical fiber 12 can be further improved.

[0044] The width w of the protruding portion 112b is preferably 0.9 to 8.0 mm, and more preferably 1.0 to 5.0 mm. If the width w is greater than or equal to the lower limit, the strain generated in the object to be measured (structure, etc.) can be accurately transmitted to the optical fiber. If the width w is less than or equal to the upper limit, the resistance is reduced when inserting it into excavation holes in structures during construction, thereby improving workability.

[0045] The thickness c of the protruding portion 112b is preferably, for example, 0.01 to 3.1 mm, and more preferably 0.3 to 2.0 mm. If the thickness c is greater than or equal to the lower limit, the strain generated in the object to be measured (structure, etc.) can be accurately transmitted to the optical fiber 12. If the thickness c is less than or equal to the upper limit, the resistance is reduced when inserting it into the excavation hole of the structure during construction, thereby improving workability.

[0046] In the cross-sectional shape of the protruding portion 112b, the angle θ of the corner formed by the top surface and the side surface is preferably 5 to 80°, and more preferably 10 to 45°. If the angle θ is greater than or equal to the lower limit, three-dimensional measurement capabilities can be further enhanced. If the angle θ is less than or equal to the upper limit, resistance is reduced when inserting it into excavation holes in structures during construction, thereby improving workability.

[0047] <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 4, 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 4 is a so-called fiber core.

[0048] When the optical fiber-supported 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, multimode 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.

[0049] The optical fiber-supported 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.

[0050] 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.

[0051] The optical fiber strand 13 of this embodiment has 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.

[0052] 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.

[0053] The coating resin layer 14 is a cured product of an adhesive resin composition (B) containing resin (B). Examples of resin (B) include polyolefin, polyester, polyamide, polyimide, and fluororesin. These resins (B) may also be elastomers containing hard segments and soft segments. Among these, polyester, polyamide, and polyimide are preferred as resin (B). Furthermore, the coating resin layer 14 may be a multilayer structure consisting of two or more layers. If it is a multilayer structure, the outermost layer is preferably polyester, polyamide, or polyimide. Resin (B) may be used alone or in combination of two or more types.

[0054] The color tone of the coating resin layer 14 (i.e., the color tone of the outer surface of the optical fiber 12) is not particularly limited and will be determined appropriately considering the application and design of the optical fiber supported molded body 1. The coating resin layer 14 may be transparent, semi-transparent, or opaque. However, from the viewpoint of making the position of the optical fiber 12 easier to see, the coating resin layer 14 is preferably semi-transparent or opaque, and more preferably opaque. The color tone and total light transmittance of the coating resin layer 14 can be adjusted by the composition (for example, the combination of the type of resin (B), the type and amount of optional component (B) in the resin composition (B) described later), thickness, etc.

[0055] The content of resin (B) relative to the total mass (100% by mass) of resin composition (B) is preferably 80% by mass or more, more preferably 90% by mass or more, and may also be 100% by mass.

[0056] The content of at least one resin selected from polyester, polyamide, polyolefin, fluororesin, and polyimide, relative to the total mass (100% by mass) of resin (B), is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass.

[0057] The resin composition (B) may contain components other than resin (B) (optional component (B)). Optional component (B) is the same as optional component (A).

[0058] 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.

[0059] The outer diameter r of the optical fiber 12 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 of the optical fiber 12 is below the upper limit, the peeling of the coating resin can be performed more easily when connecting optical fiber-supported molded bodies 10 together or when connecting the optical fiber 12 to a measuring instrument.

[0060] 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.

[0061] In this embodiment, the optical fiber-supported molded body has a transparent or semi-transparent covering portion that encloses the optical fiber, allowing the position of the optical fiber to be easily observed from the outside. Therefore, the optical fiber-supported molded body of this embodiment facilitates connection work with measuring instruments and the like.

[0062] <Other Embodiments> The present invention is not limited to the embodiments described above. In the embodiments described above, the core material has grooves and a covering portion, but the present invention is not limited thereto. The optical fiber-supported molded body of the present invention may be formed by integrally molding the core material body, the covering portion, and the optical fiber. For example, a resin composition (A) that becomes transparent or translucent after curing may be extruded into a tubular shape while an optical fiber is supplied to an extruder to form an optical fiber-supported molded body having a transparent or translucent core material and an optical fiber located within the tube wall of the core material. Alternatively, while supplying optical fibers to an extruder, an opaque resin composition (A) and a resin composition (C) that becomes transparent or translucent after curing may be extruded into a tubular shape to form an optical fiber-supported molded body having an opaque core material body, a transparent or translucent covering portion, and an optical fiber covered by the covering portion and located inside the tube wall.

[0063] The optical fiber-supported molded body of the present invention may be, for example, the optical fiber-supported molded body 20 shown in Figure 5. The optical fiber-supported molded body 20 has a cylindrical core material 21 and optical fibers 12 that are spirally embedded in 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 axis O2 direction of the core material 21 in the circumferential direction. The core material 21 has a core material body 121 and a spiral covering portion 122. In this embodiment, grooves are formed in a spiral shape, and the optical fibers 12 are located within the spiral grooves. The covering portion 122 fills the inside of the spiral grooves and covers the opening surface of the grooves. The optical fiber-supported molded body 20 also has exposed portions 23a between the covering portions 122. The optical fiber-supported molded body 20 differs from the optical fiber-supported molded body 10 only in that the optical fiber 12 forms a spiral around the axis O2 of the core material 21.

[0064] The helical pitch P of the optical fiber 12 is preferably 10 to 600 mm, more preferably 100 to 500 mm, and even more preferably 300 to 400 mm. If the helical pitch P is greater than or equal to the above upper limit, the measurement accuracy can be improved without excessively increasing the length of the optical fiber 12. If the helical pitch P is less than or equal to the above upper limit, the measurement accuracy can be further improved.

[0065] ≪Manufacturing method≫ The method for manufacturing an optical fiber-supported molded body involves placing optical fibers in grooves on a core material having grooves on its outer surface, filling the grooves with uncured coating material, and curing the filled uncured coating material to form a coating. The following describes an example of a method for manufacturing an optical fiber-supported molded body, using the optical fiber-supported molded body 20 as an example. The manufacturing method of this embodiment comprises a core material manufacturing step, a placement step, a filling step, and a hardening step.

[0066] The core material manufacturing process is the process of manufacturing the core material. Examples of core material manufacturing processes include obtaining a long member (molding process) and forming grooves on the outer surface of the obtained member to form the core material body (post-grooving method). Alternatively, a method of extruding the core material body with grooves can be used.

[0067] When manufacturing the core material body using the post-ridge formation method, one example is to manufacture a long member (for example, a resin pipe), and then feed the member out while pressing a cutting blade against the outer surface of the member.

[0068] The placement, filling, and curing processes may be carried out independently in batches or continuously. An example of a method for continuously carrying out the placement, filling, and curing processes will be explained using Figure 6. The optical fiber-supported molded body manufacturing apparatus (hereinafter sometimes simply referred to as "manufacturing apparatus") 200 in Figure 6 comprises a heater 210, four rollers 220, a filling machine 230, an outer diameter adjuster 240, a take-up machine 250, and a bundling machine 260.

[0069] Examples of heating devices 210 include infrared heating devices and steam heating devices. Examples of filling machines 230 include extrusion molding machines, molds, rotary extruders, rotary molds, and the like. Examples of outer diameter adjusting devices 240 include crimping rollers and rotating rollers. Examples of the take-up machine 250 include rotary take-up machines, take-up machines, and the like. Examples of the binding machine 260 include rotary winding machines, winding machines, and the like.

[0070] A method for manufacturing a fiber-optic supported molded body using the manufacturing apparatus 200 will be described. The core material body 121 is inserted into the heater 210 and heated to a desired temperature (heating operation). The heating operation softens the core material body 121. If the core material body 121 is a cured product of resin composition (A), the heating operation involves heating the core material body 121 to, for example, 80 to 120°C. The heated core material body 121 is taken up by the take-up machine 250. During this process, the core material body 121 is taken up while rotating in the direction of arrow F (around the axis of the core material body 121). The roller 220 supplies the optical fiber 12 to the groove of the core material body 121 and positions the optical fiber 12 within the groove (positioning process).

[0071] Uncured coating material is filled into the grooves where the optical fibers 12 are positioned from the filling machine 230. If the coating is a cured product of resin composition (C), the resin composition (C) is supplied as uncured coating material during the filling process. At this time, the uncured coating material is left to protrude from the grooves. After supplying the uncured coating material into the groove, the outer diameter adjuster 240 is used to push the uncured coating material into the groove and smooth it out. In this way, the groove is filled with the uncured coating material and the uncured coating material is raised above the opening surface of the groove (this completes the filling process).

[0072] Subsequently, the uncured coating material is cured to form the coating portion (curing step). The method for curing the uncured coating material can be appropriately determined according to the type of uncured coating material. If the uncured coating material is a resin composition (C) containing resin (C), and resin (C) is a thermoplastic resin, the uncured coating material can be cured by cooling. If resin (C) is an energy-ray curable resin, the uncured coating material is cured by irradiating it with energy rays (e.g., heat, ultraviolet light, etc.). In this way, the optical fiber 12 and the core material body 121 are joined within the groove by the cured product (coating portion) of the uncured coating material to form an optical fiber supported molded body 20. The optical fiber-supported molded body 20 is wound onto the bundling machine 260.

[0073] The optical fiber-supported molded body 20 is wound up by the bundling machine 260 and secured in several places with cable ties to prevent it from unraveling, forming a roll. This roll is brought to the construction site, the cable ties are cut, and the roll is laid while being unwound. Furthermore, by performing the placement and filling processes without rotating the core material body 121, the optical fiber supported molded body 10 shown in Figure 1 can be manufactured.

[0074] Alternatively, using the manufacturing apparatus 200a in Figure 7, the core material body 121 may not be rotated, but the filling machine 230 and the optical fiber supply machine 12 may be rotated in the F1 direction around the axis of the core material body 121 while performing the placement and filling processes. [Examples]

[0075] The present invention will be described in more detail below, but the present invention is not limited to the following embodiments.

[0076] (Materials used) <Resin (B)> L522: Polyethylene, manufactured by Mitsubishi Chemical Corporation. LB540: Polyethylene, manufactured by Mitsui Chemicals, Inc. LF300: Polyethylene, manufactured by Mitsui Chemicals, Inc. HB122R: Polyethylene, MFR = 0.14 g / min, manufactured by Nippon Polyethylene Co., Ltd. • 8100M: Polyethylene, MFR = 0.05 g / min, manufactured by PTT.

[0077] <Bare Fiber> • Fiber core: SMF28 (product name), thickness = 0.8mm, color = yellow, manufactured by THORLABS.

[0078] (Measurement method) <Haze, total light transmittance> Each resin was molded into a 1mm thick plate (unstretched) to create a flat sample. The light transmittance of the flat sample was measured using a turbidimeter (Nippon Denshoku Industries Co., Ltd. NDH2000) with a light source of D65.

[0079] <Crystallization> Measurements were performed using a differential scanning calorimeter (Hitachi High-Tech Science Corporation, DSC7020, Seiko Instruments Inc.). The sample was sealed in an aluminum container for measuring the heat of fusion. Under a nitrogen atmosphere, the temperature was raised from 20°C to 280°C at a heating rate of 10°C / min, and the heat of fusion was calculated from the obtained DSC curve. The literature value for the heat of fusion of a perfect crystal of polyethylene (286.7 J / g) was used as the reference value for 100% crystallinity, and the degree of crystallinity (%) was calculated by dividing the heat of fusion of the sample by the aforementioned literature value.

[0080] (Evaluation method) <Visibility> For each example of a molded fiber-supported body, its appearance was observed visually and evaluated according to the evaluation criteria below.

[0081] ≪Evaluation Criteria≫ ○: The position of the optical fiber within the recess can be easily identified. △: The position of the optical fiber within the recess can be recognized to some extent. ×: The position of the optical fiber within the recess cannot be recognized.

[0082] (Measurement example) For resins 1-6 listed below, the total light transmittance, haze, density, and degree of crystallinity were measured, and the results are shown in Table 1.

[0083] [Table 1]

[0084] (Example of experiment) According to the specifications shown in Table 2, a tube was formed from resin (A), and grooves with a width of 4.0 mm and a depth of 1.5 mm were formed on the outer surface of the resulting tube to form the core material body. An optical fiber (0.8 mm thick fiber core) was placed within the grooves of the core material. The grooves were filled with resin (C) to form a coating, and the optical fiber-supported molded bodies for each example were obtained. The thickness T122 of the coating was used as the thickness in Table 2. The visibility of the obtained optical fiber-supported resin tubes was evaluated, and the results are shown in the table.

[0085] [Table 2]

[0086] As shown in Table 2, experimental examples 1 to 7 to which the present invention was applied showed visibility as either "○" or "△". [Explanation of symbols]

[0087] 10, 20 Fiber optic supported molded body 11, 21 Core material 11A, 21A Cylinder wall 12, 12A optical fiber 13 Optical fiber strands 14. Coating resin layer 23, 23a Exposed part 110 Concave line 111, 121 Core material body 112, 122 Covering part O1, O2 axis

Claims

1. It comprises a long core material and one or more optical fibers located within the core material and extending in the axial direction of the core material, The core material has a covering portion that covers the optical fiber from the outer surface of the core material, The aforementioned covering portion is a semi-transparent, optical fiber-supported molded body.

2. The core material comprises a core material body having one or more grooves extending in the axial direction on its outer surface, and a covering portion that fills the grooves and covers the openings of the grooves. The optical fiber supported molded body according to claim 1, wherein the outer surface of the core material has an exposed portion in the circumferential direction where the covering portion is absent.

3. The optical fiber supported molded body according to claim 1 or 2, wherein the covering portion has a total light transmittance of 35% or more as defined in JIS K7361-1.

4. The optical fiber supported molded body according to claim 1 or 2, wherein the covering portion has a haze value of 98% or less as defined in JIS K7136.

5. The optical fiber-supported molded body according to claim 1 or 2, wherein the thickness of the coating portion on the optical fiber is 0.1 to 2.5 mm.

6. The optical fiber supported molded body according to claim 1 or 2, wherein the coating portion contains polyethylene, and the degree of crystallinity of the coating portion, as measured by DSC analysis as defined in JIS K7122, is 27 to 67%.

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