Resin molded article carrying optical fiber

Abstract

To provide an optical fiber carrying resin molding capable of further improving measurement accuracy.SOLUTION: The optical fiber-supporting resin-molded article includes a long core 11, one or more optical fibers 12 extending in the direction of the axis O1 of the core 11, and a fixing member 112 for fixing the optical fibers 12 to the core 11, wherein the optical fibers 12 each include a bare fiber and an optical-fiber coating layer covering the peripheral surface of the bare fiber, and the fixing member 112 has a melting temperature lower than the melting temperatures of the core 11 and the optical-fiber coating layer.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a resin molded article carrying an optical fiber. [Background technology]

[0002] As a sensor capable of monitoring the displacement of a structure using an optical fiber, for example, an optical fiber carrier equipped with an optical fiber is used. The optical fiber holder integrally comprises, for example, a long core material and an optical fiber extending in the axial direction of the core material. The optical fiber holder connects the optical fiber to a measuring instrument, and the measuring instrument can constantly monitor the bending, elongation, and twisting strain changes, pressure changes, and temperature changes occurring in the core material from frequency changes or phase changes of Rayleigh scattering of the optical fiber.

[0003] For example, Patent Document 1 proposes a detection device (optical fiber carrier) including a rod-shaped member made of polyolefin resin, a groove formed on the outer surface of the rod-shaped member, an optical fiber fitted into the groove, and a welding member made of polyolefin resin and fused to the rod-shaped member.As a manufacturing method of this optical fiber carrier, a method is given in which a groove (recess) is formed on the outer surface of the rod-shaped member (core material), an optical fiber is fitted into this recess, the opening of the recess is covered with the welding member, and the welding member is pushed into the recess while hot air is blown onto the welding member and the outer sheath. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-132824 Summary of the Invention [Problem to be solved by the invention]

[0005] When connecting the optical fiber of the optical fiber holder of Patent Document 1 to a measuring instrument, it is necessary to blow hot air onto the welding member to melt it, and then remove the optical fiber from within the welding member. According to the findings of the present inventors, when the welding material covering the optical fiber is melted, heat is transferred to the optical fiber, and the coating resin of the optical fiber also melts, which releases stress relaxation and causes microbend loss, which can reduce measurement accuracy.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide a resin molded article carrying an optical fiber that can further improve measurement accuracy. [Means for solving the problem]

[0007] The present invention has the following aspects. <1> An optical fiber-supported resin molding comprising a long core material, one or more optical fibers extending in the axial direction of the core material, and a fixing member for fixing the optical fibers to the core material, wherein the optical fibers comprise a bare fiber and an optical fiber coating layer covering the circumferential surface of the bare fiber, and the melting point of the fixing member is lower than both the melting point of the core material and the melting point of the optical fiber coating layer. <2> the difference between the melting point of the fixing member and the melting point of the optical fiber coating layer is 30°C or more; <1> The optical fiber-supporting resin molded article according to claim 1. <3> the melting point of the optical fiber coating layer is higher than the melting point of the core material; <1> or <2> The optical fiber-supporting resin molded article according to claim 1. <4> The melt flow rate of the fixing member is 0.5 to 4.0 g / 10 min. <1> ~ <3> 10. The resin molded article carrying an optical fiber according to claim 9, wherein the resin molded article carries an optical fiber. <5> The fixing member contains an acid-modified polyolefin resin. <1> ~ <4> 10. The resin molded article carrying an optical fiber according to claim 9, wherein the resin molded article carries an optical fiber. <6> the optical fiber coating layer comprises at least one of nylon and polyester elastomer; <1> ~ <5> 10. The resin molded article carrying an optical fiber according to claim 9, wherein the resin molded article carries an optical fiber. <7> the optical fiber coating layer is made of a photocurable resin composition; <1> ~ <5> 10. The resin molded article carrying an optical fiber according to claim 9, wherein the resin molded article carries an optical fiber. <8> the core material has one or more grooves extending in the axial direction on its outer surface, the optical fiber is positioned in the grooves, the fixing member has a filling portion filling the grooves and a protruding portion covering an opening surface of the grooves and rising above the opening surface, and the outer surface of the core material has an exposed portion in the circumferential direction where the protruding portion is not present. <1> ~ <7> 10. The resin molded article carrying an optical fiber according to claim 9, wherein the resin molded article carries an optical fiber. [Effects of the Invention]

[0008] According to the resin molded article supported by an optical fiber of the present invention, the measurement accuracy can be further improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing an optical fiber-supported resin molded article according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Figure 3] FIG. 3 is an enlarged view of an area S1 in FIG. [Figure 4] 10A and 10B are schematic cross-sectional views for explaining a method for extracting an optical fiber. [Figure 5] FIG. 10 is a perspective view showing an optical fiber-supported resin molded article according to another embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view showing a modified example of the resin molded article carrying an optical fiber. [Figure 7] FIG. 7 is an enlarged view of an area S2 in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] In this specification and claims, the use of "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0011] (Optical fiber supported resin molding) The resin molded article supported by an optical fiber of the present invention has a core material, one or more optical fibers extending in the axial direction of the core material, and a fixing member for fixing the optical fibers. An embodiment of the resin molded article carrying an optical fiber according to the present invention will be described below. 1 is a long cylindrical resin tube. The resin molded product 10 includes a cylindrical core material 11, an optical fiber 12 extending in the direction of the axis (tube axis) O1 of the core material 11 within a cylindrical wall 11A of the core material 11, and a fixing member 112.

[0012] As shown in FIGS. 2 and 3, the core material 11 has grooves 110 on its outer surface that extend in the direction of the axis O1. In this embodiment, the core material 11 has four grooves 110. The grooves 110 are recessed inward from the outer surface of the core material 11. That is, the grooves 110 open to the outer surface of the core material 11. The four grooves 110 are parallel to each other and along the axis O1. In this embodiment, the four optical fibers 12 are approximately parallel to each other in a side view.

[0013] The optical fibers 12 are positioned inside the grooves 110. In this embodiment, one optical fiber 12 is positioned inside one groove 110. The fixing members 112 fix the optical fibers 12 in the grooves 110 so that they are integrated with the core material 11. The fixing members 112 have filling portions 112a that fill the grooves 110 and protruding portions 112b that cover the opening surfaces of the grooves 110. Between any one fixing member 112 and another adjacent fixing member 112, there is an exposed portion 23 that is a region that does not have the protruding portion 112b (a region where the core material 11 is exposed). In other words, the optical fiber-supported resin molding 10 has, on its outer surface, an exposed portion 23 where no protruding portion 112b exists in the circumferential direction.

[0014] In this embodiment, the resin molded product 10 carries four optical fibers 12 inside the cylindrical wall 11A. The four optical fibers 12 are preferably arranged at positions that are rotationally symmetrical to one another in a cross section perpendicular to the tube axis O1 direction in the cylindrical wall 11A of the core material 11. In this embodiment, the optical fibers 12 are positioned at 90° intervals in a cross section perpendicular to the tube axis O1 direction of the core material 11. That is, the four optical fibers 12 are positioned at equal intervals around the tube axis O1 inside the cylindrical wall 11A.

[0015] The number of optical fibers 12 in the cylindrical wall 11A may be one or more. The number of optical fibers 12 in the cylindrical wall 11A is preferably two or more, 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, twisting and flattening displacement can be detected more effectively. The number of optical fibers 12 in the cylindrical wall 11A is preferably 20 or less. When the number of optical fibers 12 is equal to or less than the above upper limit, the mechanical strength of the core material 11 can be further increased. When there are two or more optical fibers 12, the two or more optical fibers 12 are preferably positioned at equal intervals around the tube axis O1.

[0016] The length of the resin molded product 10 carrying optical fiber is not particularly limited, and is, for example, 1 m to 1000 m.

[0017] <Core material> The core material 11 is a cylindrical molded body, but may be a polygonal tube, a solid cylinder, or a polygonal pillar.

[0018] The outer diameter R1 of the core material 11 is preferably 20 to 50 mm, more preferably 30 to 40 mm. When the outer diameter R1 is equal to or greater than the above-mentioned lower limit, signal interference between the optical fibers 12 can be better suppressed. When the outer diameter R1 is equal to or less than the above-mentioned 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 molding 10 can be further improved.

[0019] The inner diameter R2 of the core material 11 is preferably 10 to 45 mm, more preferably 30 to 40 mm. When the inner diameter R2 is equal to or greater than the above lower limit, the weight can be further reduced. When the inner diameter R2 is equal to or less than the above upper limit, the strength of the core material 11 can be further increased.

[0020] The thickness T of the cylindrical wall 11A is preferably 2.5 to 10 mm, more preferably 3 to 5 mm. When the thickness T is equal to or greater than the lower limit, even if the cylindrical wall 11A is damaged during construction of the resin molded article supported by optical fiber, 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. When the thickness T is equal to or less than the upper limit, the core material 11 can more easily follow the displacement of the structure, and the accuracy of measurement by the resin molded article supported by optical fiber 10 can be further improved.

[0021] The recessed ribs 110 become narrower in width from the outer surface toward the inside (direction of the axis O1) of the core material 11. That is, the recessed ribs 110 have narrower width portions that become narrower in width from the outer surface toward the inside.

[0022] The cross-sectional shape of the groove 110 may or may not have a narrowed width portion. The cross-sectional shape of the groove 110 may be V-shaped, U-shaped, or rectangular with the same width from the opening to the bottom. From the viewpoint of ease of processing and ease of arranging the optical fiber 12 in the groove 110, the cross-sectional shape of the groove 110 is preferably a shape with a narrowed width portion (e.g., V-shaped, U-shaped, etc.). For example, the groove 110 may deepen from the outer surface of the core material 11 toward the inside at the same width, and then become a narrowed width portion. Alternatively, the groove 110 may narrow from the outer surface toward the inside, and then deepen at the same width.

[0023] The opening width W1 (maximum width in this embodiment) 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 W1 is equal to or greater than the above-mentioned lower limit, the optical fiber 12 can be more reliably protected when inserted into a borehole or the like of a measurement target (structure or the like) during construction. If the opening width W1 is equal to or less than the above-mentioned upper limit, the fixing member 112 can be more easily peeled off from the core material 11, and the workability when removing the optical fiber 12 can be further improved. The opening width W1 in this embodiment is the width of the opening surface of the recessed rib 110. The width of the opening surface is the distance between the point of contact P-P' between the tangent line Q (FIG. 3) and the outer surface of the core material 11 when the tangent line Q is drawn to the opening surface.

[0024] The depth D of the grooves 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. When the depth D is equal to or greater than the lower limit, the positional accuracy of the optical fiber can be further improved. When the depth D is equal to or less than the upper limit, the strength of the core material can be further improved. Furthermore, the ratio of the depth D to the thickness T of the cylindrical wall 11A (D / T ratio) is preferably 0.1 to 1.8, more preferably 0.2 to 1.0, and even more preferably 0.3 to 0.8. When the D / T ratio is equal to or greater than the lower limit, the positional accuracy of the optical fiber can be further improved. When the D / T ratio is equal to or less than the upper limit, the strength of the cylindrical wall 11A can be further improved. The depth D is the distance from the tangent line Q to the bottom of the groove 110 .

[0025] The core material 11 is a cured product of a resin composition (A) containing a resin (A). The melting point of the core material 11 is higher than the melting point of the fixing member 112. The melting point will be described later. Examples of the resin (A) include polyolefin resins such as polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer, etc. The resin (A) may be used alone or in combination of two or more.

[0026] The resin composition (A) may contain a component (optional component (A)) other than the resin (A). That is, the core material 11 may contain the optional component (A). Examples of the optional component (A) include known additives used in polyolefin resins, such as plasticizers, colorants (pigments, dyes), lubricants, ultraviolet absorbers, and antioxidants.

[0027] The melt flow rate (MFR) of the resin composition (A) (i.e., the MFR of the resin core 11) is, for example, preferably 0.1 to 1.3 g / 10 min, and more preferably 0.2 to 0.8 g / 10 min. When the MFR of the cylindrical wall 11A is equal to or greater than the above lower limit, the core 11 can be more easily molded. When the MFR of the core 11 is equal to or less than the above upper limit, the mechanical strength of the core 11 can be further increased. MFR is a value measured in accordance with Method A of ISO 1133 "Mass flow rate and volume flow rate of plastics" at 190°C and a load of 2.16 kg.

[0028] The density of the resin composition (A) (i.e., the density of the cylindrical wall 11A) is 0.920 to 0.960 g / cm 3 is preferable, and 0.93 to 0.95 g / cm 3 It is more preferable that the density of the cylindrical wall 11A is equal to or higher than the lower limit, the rigidity can be further increased. If the density of the cylindrical wall 11A is equal to or lower than the upper limit, molding shrinkage can be suppressed. The density is a value measured in accordance with ISO 1183-1:2019 "Plastics - Determination of density of non-cellular plastics - Part 1: Immersion method, liquid pycnometer method and titration method."

[0029] <Optical fiber> The optical fiber 12 has a bare fiber and an optical fiber coating layer. The optical fiber coating layer may be one layer or two or more layers. The optical fiber 12 may be an optical fiber wire in which the outer periphery (surface) of a bare fiber is coated with a photocurable resin composition, or may be an optical fiber core wire in which the outer periphery of the optical fiber wire is further coated with a thermoplastic resin composition. The optical fiber 12 may be an optical fiber wire or an optical fiber core wire known in optical fiber displacement sensors. The surface (outer surface) of the optical fiber coating layer may be roughened by any method, including, but not limited to, mechanical methods such as sandblasting, physical methods such as corona treatment, and chemical methods such as primer treatment and etching.

[0030] A bare fiber is a fiber made of only glass and consisting of a core and at least one cladding layer surrounding the core. The refractive index of the cladding layer is lower than that of the core. The present invention is not limited to this, and the bare fiber may not have a cladding layer. However, a bare fiber having a core and a cladding layer is preferable. By having a core and a cladding layer, the bare fiber can generate scattered light derived from strain or temperature of the core, such as Brillouin scattering or Raman scattering, by injecting discontinuous pump light such as laser light into the core, thereby further improving measurement accuracy.

[0031] The core may be made of, for example, silica glass. It may contain a dopant to adjust the refractive index. The cladding layer may be made of the same material as the core. It may contain a dopant to adjust the refractive index. The materials of the core and cladding layer, other than the dopant, may be the same or different.

[0032] The thickness of the optical fiber coating layer is, for example, preferably 5 to 950 μm, more preferably 10 to 900 μm, and even more preferably 15 to 850 μm. If the thickness is equal to or greater than the above lower limit, the mechanical strength of the optical fiber 12 can be further increased. If the thickness is equal to or less than the above upper limit, the optical fiber coating layer can be more easily peeled off during splicing.

[0033] The outer diameter r of the optical fiber 12 is preferably 125 to 2000 μm, and more preferably 150 to 1000 μm. When the outer diameter r is equal to or greater than the above lower limit, the optical fiber is less likely to break when a load is applied, thereby improving productivity and durability. When the outer diameter of the optical fiber 12 is equal to or less than the above upper limit, the optical fiber coating layer can be more easily peeled off when connecting optical fiber-supported resin molded products 10 together or when connecting the optical fiber 12 to a measuring instrument.

[0034] The ratio of the opening width W1 to the outer diameter r (W1 / r ratio) is preferably 1.0 to 8.1, more preferably 2.0 to 7.0, and even more preferably 3.0 to 6.0. When the W1 / r ratio is equal to or greater than the lower limit, the workability in arranging the optical fiber 12 in the groove 110 can be further improved. When the W1 / r ratio is equal to or less than the upper limit, the strength of the core material can be further increased.

[0035] The ratio of the depth D to the outer diameter r (D / r ratio) is preferably 1.0 to 3.0, more preferably 1.1 to 2.0, and even more preferably 1.2 to 1.5. When the D / r ratio is equal to or greater than the above lower limit, the optical fiber 12 can be more reliably protected. When the D / r ratio is equal to or less than the above upper limit, the strength of the core material can be further increased.

[0036] The optical fiber coating layer is a cured product of a resin composition (B) containing a resin (B). The melting point of the optical fiber coating layer is higher than that of the fixing member 112. It is preferably higher than that of the core material 11. The melting point will be described later. The resin composition (B) is preferably a thermoplastic resin composition in which the resin (B) contains a thermoplastic resin, or a photocurable resin composition in which the resin (B) contains a photocurable resin. Examples of the thermoplastic resin include polyolefin, polyester, polyamide, polyimide, fluororesin, etc. These resins may be elastomers containing hard segments and soft segments. Examples of the photocurable resin include phenol resin and epoxy resin. The resin (B) may be used alone or in combination of two or more.

[0037] When resin (B) is a thermoplastic resin, it is preferable that resin (B) contains at least one of nylon and polyester elastomer from the viewpoint of cost. For example, the total content of nylon and polyester elastomer relative to the total mass of resin (B) is preferably 80 mass% or more, more preferably 90 mass% or more, and may be 100 mass%.

[0038] The resin composition (B) may contain a component (optional component (B)) other than the resin (B). That is, the optical fiber coating layer may contain the optional component (B). Examples of the optional component (B) include additives known in the optical fiber coating layer.

[0039] <Fixing material> The fixing member 112 has a filling portion 112a and a protruding portion 112b. The filling portion 112a and the protruding portion 112b are an integrally molded body. The filling portion 112a fills the recessed rib 110. The protruding portion 112b covers the opening surface of the recessed rib 110 and protrudes above the opening surface of the recessed rib 110. Because the fixing member 112 has the protruding portion 112b, it can be visually confirmed that the inside of the recessed rib 110 is filled with the filling portion 112a and that there are no voids within the recessed rib 110.

[0040] The width W2 of the convex streak portion 112b is preferably equal to or wider than the opening width W1 of the concave streak 110, and more preferably wider than the opening width W1. When the width W2 is equal to or wider than the opening width W1, the adhesion between the core material 11 and the optical fiber 12 can be further improved.

[0041] The width W2 of the convex ridge portion 112b is preferably, for example, 0.9 to 8.0 mm, and more preferably 1.0 to 5.0 mm. When the width W2 is equal to or greater than the above-mentioned lower limit, strain occurring in the measurement target (structure, etc.) can be transmitted to the optical fiber with high accuracy. When the width W2 is equal to or less than the above-mentioned upper limit, resistance is reduced when inserting the optical fiber into a borehole, etc., in the structure during construction, thereby further improving workability.

[0042] The ratio of the width W2 to the opening width W1 (W2 / W1 ratio) is preferably 1.0 to 21.0, and more preferably 3.0 to 11.0. When the W2 / W1 ratio is equal to or greater than the above lower limit, the fixing member 112 can be more firmly joined to the core material 11. When the W2 / W1 ratio is equal to or less than the above upper limit, resistance is reduced when inserting the fixing member 112 into a borehole or the like in a structure during construction, thereby improving workability.

[0043] The thickness c of the ridge portion 112b is preferably, for example, 0.3 to 3.1 mm, and more preferably 1.0 to 2.0 mm. When the thickness c is equal to or greater than the above lower limit, strain occurring in the measurement target (structure, etc.) can be transmitted to the optical fiber with high accuracy. When the thickness c is equal to or less than the above upper limit, resistance is reduced when inserting the optical fiber into a borehole, etc., in the structure during construction, thereby further improving workability.

[0044] In the cross-sectional shape of the convex ridge portion 112b, the angle θ of the corner formed by the top surface and the side surface is preferably 5 to 170°, and more preferably 45 to 140°. If the angle θ is equal to or greater than the above lower limit, resistance is reduced when inserting the convex ridge portion 112b into a borehole or the like in a structure during construction, thereby improving workability. If the angle θ is equal to or less than the above upper limit, resistance is reduced when inserting the convex ridge portion 112b into a borehole or the like in a structure during construction, thereby improving workability. In the cross-sectional shape of the protruding ridge portion 112b, the corner formed by the top surface and the side surface may have a straight or curved corner cut.

[0045] The fixing member 112 is a cured product of a resin composition (C) containing a thermoplastic resin (C). The melting point of the fixing member 112 is lower than both the melting point of the core material 11 and the melting point of the optical fiber coating layer. The melting point will be described later. The thermoplastic resin (C) preferably contains an acid-modified polyolefin. Examples of acid-modified polyolefins include acid (including anhydride) modified products of polyolefins such as polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer. Among these, maleic acid (anhydride) modified resins of polyethylene, acrylic acid modified resins of polyethylene, and fumaric acid modified resins of polyethylene are preferred. When the thermoplastic resin (C) contains an acid-modified polyolefin, the adhesive strength of the fixing member 112 can be increased. One type of thermoplastic resin (C) may be used alone, or two or more types may be used in combination. The thermoplastic resin (C) may contain a resin other than the acid-modified polyolefin. The content of the acid-modified polyolefin relative to the total mass (100 mass%) of the thermoplastic resin (C) is preferably 80 mass% or more, more preferably 90 mass% or more, and may be 100 mass%.

[0046] The resin composition (C) may contain a component (optional component (C)) other than the thermoplastic resin (C). The optional component (C) is the same as the optional component (A). The content of the thermoplastic resin (C) relative to the total mass (100 mass%) of the resin composition (C) is preferably 80 mass% or more, more preferably 90 mass% or more, and may be 100 mass%.

[0047] The MFR of the fixing member 112 (i.e., the MFR of the resin composition (C)) is preferably 0.1 to 3.7 g / 10 min, and more preferably 0.8 to 2.0 g / 10 min. When the MFR of the fixing member 112 is equal to or greater than the above lower limit, the fixing member 112 can be more easily molded. When the MFR of the fixing member 112 is equal to or less than the above upper limit, the mechanical strength of the fixing member 112 can be further increased.

[0048] The MFR of the fixing member 112 may be the same as or different from the MFR of the core material 11. From the viewpoint of easily peeling the fixing member 112 from the core material 11 when exposing the optical fiber 12, it is preferable that the MFR of the fixing member 112 and the MFR of the core material 11 are different.

[0049] (Melting Point) In the resin molded article carried with an optical fiber of this embodiment, the melting point M3 of the fixing member is lower than both the melting point M1 of the core material and the melting point M2 of the optical fiber coating layer. In the optical fiber extraction method described below, when the fixing member is heated and melted to extract the optical fiber, if the melting point M3 of the fixing member is lower than the melting point M2 of the optical fiber coating, the fixing member melts but the optical fiber coating does not. Therefore, stress fluctuations in the optical fiber can be prevented during the optical fiber extraction process, and measurement accuracy can be further improved. Furthermore, when the fixing member is heated and melted to extract the optical fiber, if the melting point M3 of the fixing member is lower than the melting point M1 of the core material, the core material will not melt even if the fixing member melts. This prevents deformation of the core material during the process of extracting the optical fiber, further improving measurement accuracy. In addition, when the fixing member or the optical fiber coating layer contains two or more resins with different melting points, i.e., when there are two or more melting points, the highest melting point in the fixing member is defined as M3, and the lowest melting point in the optical fiber coating layer is defined as M2, with M3 being lower than M2. Furthermore, when the optical fiber 12 has two or more optical fiber coating layers, the lowest melting point among the optical fiber coating layers is defined as M2, and M3 is set lower than M2. Usually, the melting point of the coating layer (thermoplastic resin composition) of the optical fiber core is lower than the melting point of the coating layer (photocurable resin composition) of the optical fiber core. Furthermore, when the fixing member or core material contains two or more resins with different melting points, i.e., when there are two or more melting points, the highest melting point in the fixing member is designated as M3, the lowest melting point in the core material is designated as M1, and M3 is lower than M1.

[0050] The difference (M2-M3) between the melting point M2 of the optical fiber coating layer and the melting point M3 of the fixing member is preferably 30°C or more, more preferably 50°C or more, and even more preferably 70°C or more. If the difference between M2 and M3 is equal to or greater than the above-mentioned lower limit, stress fluctuations in the optical fiber can be more reliably prevented from occurring in the optical fiber during the process of extracting the optical fiber. There is no particular upper limit for the difference between M2 and M3, but from the viewpoint of fixing the optical fiber, it is preferably 260°C or less, more preferably 160°C or less, and even more preferably 120°C or less.

[0051] The difference (M1-M3) between the melting point M1 of the core material and the melting point M3 of the fixing member is preferably 1°C or more, more preferably 10°C or more, and even more preferably 20°C or more. If the difference between M1 and M3 is equal to or greater than the above-mentioned lower limit, deformation of the core material can be more reliably prevented during the process of extracting the optical fiber. There is no particular upper limit for the difference between M1 and M3, but from the viewpoint of temperature control during molding, it is preferably 50°C or less, more preferably 40°C or less, and even more preferably 30°C or less.

[0052] The melting point M2 of the optical fiber coating layer is preferably higher than the melting point M1 of the core material. In the optical fiber extraction method described below, when the fixing member is heated and melted to extract the optical fiber, if the melting point M2 of the optical fiber coating layer is higher than the melting point M1 of the core material, stress fluctuations in the optical fiber can be more reliably prevented during the optical fiber extraction process. In addition, when the core material or the optical fiber coating layer contains two or more resins with different melting points, i.e., when there are two or more melting points, the highest melting point in the core material is designated as M1, and the lowest melting point in the optical fiber coating layer is designated as M2, with M2 being higher than M1.

[0053] The difference (M2-M1) between the melting point M2 of the optical fiber coating layer and the melting point M1 of the core material is preferably 30°C or more, more preferably 50°C or more. If the difference between M2 and M1 is equal to or greater than the above-mentioned lower limit, stress fluctuations in the optical fiber can be more reliably prevented from occurring in the process of extracting the optical fiber. There is no particular upper limit for the difference between M2 and M1, but from the viewpoint of workability in removing the optical fiber coating layer, it is preferably 370°C or less, more preferably 300°C or less, and even more preferably 250°C or less.

[0054] The melting point M1 of the core material 11 is preferably 100 to 151° C., more preferably 110 to 141° C., and even more preferably 120 to 131° C. If the melting point M1 of the core material 11 is not less than the lower limit, the strength of the core material increases, and if it is not more than the upper limit, the flexibility is good and measurement accuracy increases. The melting point M2 of the optical fiber coating layer is preferably 160 to 370° C., more preferably 170 to 280° C., and even more preferably 190 to 240° C. Although not particularly limited, when the melting point M2 of the optical fiber coating layer is equal to or higher than the above lower limit, the workability of taking out the optical fiber improves, and when it is equal to or lower than the above upper limit, the workability of removing the optical fiber coating layer improves. The melting point M3 of the fixing member is preferably 90 to 150° C., more preferably 95 to 140° C., and even more preferably 100 to 130° C. Although not particularly limited, when the melting point M3 of the fixing member is equal to or higher than the above lower limit, molding and handling are improved, and when it is equal to or lower than the above upper limit, workability in taking out the optical fiber is improved.

[0055] [Manufacturing method] The optical fiber-supported resin molding of this embodiment can be manufactured by placing the optical fiber 12 in the groove 110 of a core material 11 having a groove 110 on its outer surface, filling the groove 110 with uncured material for the fixing member 112 (uncured resin material), and curing the filled uncured resin material to form the fixing member 112. The core material 11 having the grooves 110 on its outer surface can be manufactured, for example, by forming a long member and then using a technique such as cutting to form the grooves 110 on its outer surface, or by extrusion molding the core material 11 having the grooves 110. After placing the optical fiber 12 in the grooves 110, uncured resin material is supplied and pressed into the grooves, and the uncured resin material is leveled to fill the grooves and cause the uncured resin material to protrude from the openings of the grooves. The uncured resin material is then cooled and hardened, resulting in a fixing member 112 having a shape including a filling portion 112a that fills the grooves 110 and a protruding portion 112b that covers the openings of the grooves 110.

[0056] In the resin molded product 10 supported on optical fiber thus obtained, the fixing member 112 is joined to the optical fiber 12 and the core material 21 within the grooves 110, and integrally fixes the core material 21 and the optical fiber 12. In addition, since the fixing member 112 has the protruding portions 112b, the uncured resin material is filled in an amount greater than that which fills the grooves, and it can be visually confirmed from the appearance that the grooves 110 are filled with the filled portions and do not have voids. Therefore, the resin molded product supported on optical fiber of this embodiment can further improve measurement accuracy.

[0057] [How to extract optical fiber] When applying the resin molded product 10 carrying an optical fiber of this embodiment, it is necessary to take out the optical fiber 12 from a desired take-out position (for example, an end portion) of the resin molded product 10 carrying an optical fiber. 4, when the optical fiber is removed from the optical fiber-supported resin molding of this embodiment, the fixing member 112 at the removal position is heated to a temperature equal to or higher than the melting point to melt it, and the optical fiber is removed from inside the melted fixing member 112. Heating means H for heating the fixing member 112 can be, for example, a device that blows hot air.

[0058] <Other embodiments> The present invention is not limited to the above-described embodiments. The resin molded product supported by an optical fiber of the present invention may be, for example, a resin molded product supported by an optical fiber 20 shown in FIG. The resin molded product 20 of this embodiment differs from the resin molded product 10 of the above embodiment in that the optical fiber 12 forms a spiral around the axis O2 of the core material 21. The resin molded product 20 carries an optical fiber, and includes a cylindrical core 21, an optical fiber 12 embedded in a cylindrical wall 21A of the core 21 in a spiral shape at an inclination angle of more than 0 degrees and less than 90 degrees from the axis O2 direction of the core 21 toward the circumferential direction, and a spiral fixing member 122. In this embodiment, the grooves are formed in a spiral shape, and the optical fiber 12 is positioned within the spiral grooves. The fixing member 122 fills the spiral grooves and covers the opening surfaces of the grooves. The resin molded product 20 carries an exposed portion 23a between the fixing members 122. Although FIG. 5 shows only one optical fiber 12 and the fixing member 122 that fixes it, the other three optical fibers 12 and the fixing members 122 that fix them are also present in a spiral shape.

[0059] The helical pitch P1 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 P1 is equal to or greater than the upper limit, the measurement accuracy can be improved without excessively increasing the length of the optical fiber 12. If the helical pitch P1 is equal to or less than the upper limit, the measurement accuracy can be further improved.

[0060] In this embodiment, the melting point M1 of the core material 21, the melting point M2 of the optical fiber coating layer, and the melting point M3 of the fixing member 122 are set in the same manner as in the above embodiment, thereby achieving the same effects.

[0061] <Modification> In the above-described embodiments of the resin molded optical fiber support 10, 20, the fixing members 112, 122 are provided intermittently in the circumferential direction of the core material via the exposed portions 23, 23a, but the fixing members may be present over the entire circumferential direction of the core material. In addition, in the optical fiber-supported resin moldings 10 and 20, grooves are provided on the outer surface of the core material and the optical fiber is housed within these grooves, but the optical fiber may also be placed outside the core material and fixed together.

[0062] For example, the resin molded article 30 carrying an optical fiber may have the configuration shown in FIGS. The optical fiber-supported resin molding 30 of this example has a cylindrical core material 31 and a layer-like fixing member 132 that covers the entire outer surface of the core material 31, and has an optical fiber 12 that extends in the direction of the axis (tube axis) O3 of the core material 31 within the fixing member 132. The optical fiber 12 of this example is an optical fiber core having an optical fiber strand 12a and an optical fiber coating layer 12b. In this example, the melting point M1 of the core material 31, the melting point M2 of the optical fiber coating layer 12b, and the melting point M3 of the fixing member 132 are set in the same manner as in the above embodiment, thereby achieving the same effect. [Explanation of symbols]

[0063] 10, 20, 30 Optical fiber-supported resin molding 11, 21, 31 Core material 12 Optical Fiber 23, 23a Exposed part 110 Concave line 112, 122, 132 Fixing member 112a Filling section 112b Convex part O1, O2, O3 axis

Claims

1. A long core material and one or more optical fibers extending in the axial direction of the core material; a fixing member that fixes the optical fiber to the core material, the optical fiber has a bare fiber and an optical fiber coating layer that covers a peripheral surface of the bare fiber, The resin molded article carrying an optical fiber, wherein the melting point of the fixing member is lower than both the melting point of the core material and the melting point of the optical fiber coating layer.

2. 2. The resin molded article supported by an optical fiber according to claim 1, wherein the difference between the melting point of said fixing member and the melting point of said optical fiber coating layer is 30[deg.] C. or more.

3. 2. The resin molded article supported by an optical fiber according to claim 1, wherein the melting point of said optical fiber coating layer is higher than the melting point of said core material.

4. 2. The resin molded article supported by an optical fiber according to claim 1, wherein the fixing member has a melt flow rate of 0.5 to 4.0 g / 10 min.

5. The resin molded article supported by an optical fiber according to claim 1 , wherein the fixing member comprises an acid-modified polyolefin.

6. 2. The resin molded article supported by an optical fiber according to claim 1, wherein the optical fiber coating layer contains at least one of nylon and polyester elastomer.

7. 2. The resin-molded article supported by an optical fiber according to claim 1, wherein the optical fiber coating layer is made of a photocurable resin composition.

8. the core member has one or more grooves extending in the axial direction on its outer surface; the optical fiber is located within the groove; The fixing member has a filling portion that fills the recessed streak and a protruding streak portion that covers an opening surface of the recessed streak and protrudes above the opening surface, 8. The resin molded article supported by an optical fiber according to claim 1, wherein an outer surface of the core material has an exposed portion in the circumferential direction where the convex ridge portion is not present.

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