Optical fiber ribbon core and method for manufacturing optical fiber ribbon core

Abstract

To provide an optical fiber ribbon core that can prevent winding collapse during bobbin winding and has high single-core isolation properties. [Solution] The optical fiber ribbon core according to the present invention comprises a plurality of colored optical fiber cores arranged in parallel, and a ribbon layer that covers the plurality of colored optical fiber cores and connects the plurality of colored optical fiber cores, wherein the equilibrium modulus of the ribbon layer is 12.5 MPa or more and 48.3 MPa or less, and the storage modulus of the ribbon layer at 25°C is 1210 MPa or more.

Description

Technical Field

[0001] The present invention relates to an optical fiber ribbon core wire and a method for manufacturing the same.

Background Art

[0002] Patent Document 1 discloses a technique for forming a single optical fiber ribbon core wire by coating a plurality of optical fiber colored core wires with a ribbon layer formed of an ultraviolet curable resin and connecting the plurality of optical fiber colored core wires. Further, Patent Document 2 discloses a technique for improving the lubricity of the surface of an optical fiber ribbon core wire during bobbin winding by forming a coating layer of the optical fiber ribbon core wire using a resin composition containing a lubricating resin. Patent Document 3 discloses a technique for improving the single-core separability of an optical fiber ribbon core wire by forming a colored layer on the outer periphery of an optical fiber element wire through an adhesive layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Optical fiber ribbon cores are held in a wound state on a bobbin during manufacturing. To prevent winding collapse during bobbin winding, the storage modulus of the ribbon layer, which is the outermost layer of the optical fiber ribbon core, must be high. On the other hand, to maintain the single-core separability of the optical fiber ribbon core, the elongation at break of the ribbon layer must be high, that is, the equilibrium modulus must be low. However, since there is a trade-off relationship between modulus and elongation at break, it has been difficult to maintain high single-core separability while preventing winding collapse during bobbin winding.

[0005] Therefore, in view of the above-mentioned problems, the present invention aims to provide an optical fiber ribbon core and a method for manufacturing an optical fiber ribbon core that can prevent winding collapse during bobbin winding and have high single-core separation properties. [Means for solving the problem]

[0006] According to one aspect of the present invention, an optical fiber ribbon core is provided, comprising a plurality of colored optical fiber cores arranged in parallel, and a ribbon layer covering the plurality of colored optical fiber cores and connecting the plurality of colored optical fiber cores, wherein the equilibrium modulus of the ribbon layer is 12.5 MPa or more and 48.3 MPa or less, and the storage modulus of the ribbon layer at 25°C is 1210 MPa or more.

[0007] According to another aspect of the present invention, a method for manufacturing an optical fiber ribbon core is provided, comprising the steps of: arranging a plurality of colored optical fiber cores in parallel; and forming a ribbon layer that covers the plurality of colored optical fiber cores and connects the plurality of colored optical fiber cores, wherein the equilibrium modulus of the ribbon layer is 12.5 MPa or more and 48.3 MPa or less, and the storage modulus of the ribbon layer at 25°C is 1210 MPa or more. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an optical fiber ribbon core that can prevent winding collapse during bobbin winding and has high single-core separation properties, as well as a method for manufacturing the same. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of an optical fiber ribbon core in one embodiment. [Figure 2] This is a cross-sectional view of a colored optical fiber core in one embodiment. [Figure 3] This is a cross-sectional view showing an example of a sample piece of ribbon layer used in testing an optical fiber ribbon core in one embodiment. [Figure 4] This figure illustrates the single-core separation of an optical fiber ribbon in one embodiment. [Figure 5] This is a schematic diagram of a manufacturing apparatus for optical fiber ribbon cores in one embodiment. [Figure 6] This is a block diagram of a control device in one embodiment. [Figure 7] This is a flowchart of a method for manufacturing an optical fiber ribbon core in one embodiment. [Figure 8] This is a flowchart of the method for manufacturing the ribbon layer in one embodiment. [Figure 9] This is a cross-sectional view of an optical fiber ribbon core in a modified embodiment. [Figure 10] This is a cross-sectional view of an optical fiber ribbon core in a modified embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. Throughout this specification, the same reference numerals mean substantially the same components.

[0011] Figure 1 is a cross-sectional view of the optical fiber ribbon core 1 in this embodiment. The optical fiber ribbon core 1 comprises four colored optical fiber cores 3 arranged in parallel and a ribbon layer 2. The colored optical fiber cores 3 are bundled together in a strip shape by the ribbon layer 2. The number of colored optical fiber cores 3 is not limited to this, and for example, they may be bundled in groups of 2, 8, 12, or 24.

[0012] The ribbon layer 2 is the outermost layer of the optical fiber ribbon core wire 1. The ribbon layer 2 is formed of an ultraviolet curable resin and is coated on the outer periphery of a plurality of optical fiber colored core wires 3. The ribbon layer 2 has a function of protecting the optical fiber colored core wire 3 from external forces. The ribbon layer 2 is formed by curing the ultraviolet curable resin by irradiation with ultraviolet rays. The ribbon layer 2 is formed in a substantially oval shape on the outer periphery of four optical fiber colored core wires 3 in a cross-sectional view.

[0013] FIG. 2 is a cross-sectional view of the optical fiber colored core wire 3 in the present embodiment. The optical fiber colored core wire 3 includes an optical fiber bare wire 31, a primary layer 32, a secondary layer 33, and a coloring layer 34. The optical fiber bare wire 31 is formed of, for example, quartz-based glass or the like. The primary layer 32 is formed of an ultraviolet curable resin and is coated on the outer periphery of the optical fiber bare wire 31. The secondary layer 33 is formed of an ultraviolet curable resin and is coated on the outer periphery of the primary layer 32. The primary layer 32 and the secondary layer 33 are each formed by curing the ultraviolet curable resin by irradiation with ultraviolet rays. In this specification, the optical fiber bare wire 31, the primary layer 32, and the secondary layer 33 are collectively referred to as an "optical fiber element wire". However, the configuration of the optical fiber element wire 31 is not limited to the above configuration, and for example, it may be formed of a single coating layer.

[0014] The coloring layer 34 is the outermost layer of the optical fiber colored core wire 3. The coloring layer 34 has a function of protecting the optical fiber bare wire 31, the primary layer 32, and the secondary layer 33 from external forces. The coloring layer 34 is formed of an ultraviolet curable resin and is coated on the outer periphery of the secondary layer 33. The coloring layer 34 is formed by curing the ultraviolet curable resin by irradiation with ultraviolet rays in the same manner as the primary layer 32 and the secondary layer 33. The ultraviolet curable resin forming the coloring layer 34 may include additives such as oligomers, monomers, etc., and lubricants such as photoinitiators, photosensitizers, ultraviolet absorbers, antioxidants, chain transfer agents, silicone, and titanium oxide.

[0015] Further, the coloring layer 34 is colored with a colorant mixed with a pigment, a lubricant, or the like so as to be able to distinguish a plurality of optical fiber colored cores 3. The types of colors can be, for example, white, black, gray, purple, blue, light blue, green, brown, yellow, orange, pink, red, and the like. Note that the coloring layer 34 may be a secondary layer 33 colored with a colorant. In this case, by containing the same colorant as the colorant that colors the ultraviolet curable resin used for the coloring layer 34 in the ultraviolet curable resin used for the secondary layer 33, the secondary layer 33 can be colored.

[0016] In the present embodiment, the ultraviolet curable resin forming the primary layer 32, the secondary layer 33, the coloring layer 34, and the ribbon layer 2 is, for example, a urethane acrylate (methacrylate)-based ultraviolet curable resin. The urethane acrylate (methacrylate)-based ultraviolet curable resin is composed of an oligomer, a monomer, and the like. The ultraviolet curable resin composition appropriately contains additives such as a photoinitiator, a photosensitizer, a chain transfer agent, an ultraviolet absorber, an antioxidant, a silane coupling agent, a lubricant such as silicone, and a pigment such as titanium oxide. By appropriately adjusting the molecular weight, the number of branches, the type of functional group, the number of functional groups of the oligomer, the molecular weight, the type of functional group, the number of functional groups of the monomer, the components and the blending ratio of the ultraviolet curable resin composition, physical properties such as conversion rate, Young's modulus, storage elastic modulus, elongation at break, and equilibrium elastic modulus can be changed and controlled. Note that the molecular weight of the oligomer can be measured, for example, by gel permeation chromatography (GPC). In GPC, for example, tetrahydrofuran is used as a solvent, and it can be calculated as the relative molecular weight to polystyrene.

[0017] Examples of photoinitiators include 1-hydroxycyclohexyl-phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl bis(p-tolyl)phosphine oxide, ethyl (2,4,6-trimethylbenzoyl)(phenyl)phosphinate, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. Examples include photoinitiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one. However, the types of photoinitiators are not limited to those mentioned above.

[0018] By adding photoinitiators and photosensitizers, UV curing using UV-LEDs can be performed efficiently. For example, photoinitiators with an absorption range of 300 nm or higher include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl bis(p-tolyl)phosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. In addition, photosensitizers with an absorption range of 300 nm or higher include 2,4-diethyl-9H-thioxanthen-9-one and 2-isopropylthioxanthone.

[0019] Furthermore, to promote the reaction between the silane coupling agent and the bare optical fiber 31, an additive that generates acid upon ultraviolet irradiation (photoacid generator) may be added as appropriate. An example of a photoacid generator is CPI-200K manufactured by Sunapro Co., Ltd. However, the type of photoacid generator is not limited to this.

[0020] Mercapto-containing compounds may be added to adjust the Young's modulus of UV-curable resins. Mercapto-containing compounds have the effect of stopping the polymerization of polymerizable compounds, such as urethane (meth)acrylate contained in UV-curable resins, by reacting with the mercapto group. Examples of mercapto-containing compounds include isooctyl 3-mercaptopropionate and ethyl mercaptan. Mercaptan, 1-Butanethiol, 1-Heptanethiol, 1-Undecanethiol, 4-Hydroxybenzenethiol, (2-Mercaptoethyl)pyrazine, 2,3-Butanedithiol, 3-Methyl-2-butanethiol, 3-Mercapto-1,2,4-triazole, 1,3,4-Thiadiazole-2-thiol, Isobutyl mercaptan Examples include mercaptan, 4-methoxy-α-toluenethiol, 4,4'-biphenyldithiol, trimethylsilylmethanethiol, 1,4-butanedithiol, 1,8-octanedithiol, 3-ethoxybenzenethiol, and pentaerythritol tetra(3-mercaptopropionate). However, the types of mercapto-containing compounds are not limited to these. Furthermore, compounds that react with UV-curable resins to halt polymerization may be added, in addition to mercapto-containing compounds.

[0021] Ultraviolet irradiation is performed using, for example, a mercury lamp or a UV-LED light source, at an appropriate illuminance and irradiation dose. The Young's modulus of the primary layer 32, the secondary layer 33, and the colored layer 34 varies depending on the manufacturing conditions of the optical fiber (e.g., linear velocity, UV irradiation intensity, UV light source type, resin coating temperature, etc.) and cannot be uniquely determined by the UV-curable resin used.

[0022] The diameter of the bare optical fiber 31 is 80 μm or more and 150 μm or less, preferably 124 μm or more and 126 μm or less. The thickness of the primary layer 32 may be 5 μm or more and 60 μm or less. The thickness of the secondary layer 33 may be 5 μm or more and 60 μm or less. The thickness of the colored layer 34 may be several μm. Here, the diameter of the optical fiber strand can be determined by the sum of the diameter of the bare optical fiber 31, twice the length of the primary layer 32, and twice the length of the secondary layer 33. Therefore, the diameter of the bare optical fiber 31, the thickness of the primary layer 32, and the thickness of the secondary layer 33 can be selected so that the diameter of the optical fiber strand is approximately 120 to 280 μm.

[0023] [Measurement of Young's modulus] The Young's modulus of the primary layer 32 corresponds to ISM (In Situ Modulus). The measurement of the Young's modulus of the primary layer 32 (P-ISM) is defined as being measured by the following method. First, using a commercially available stripper, the primary layer 32 and secondary layer 33 of the middle section of a sample optical fiber, which has been conditioned in an atmosphere of 23°C and 50% relative humidity, are stripped off to a length of several millimeters. Then, one end of the optical fiber with the coating layer formed is fixed onto a glass slide with adhesive, and a load F is applied to the other end of the optical fiber with the coating layer formed. In this state, the displacement δ of the primary layer 32 at the boundary between the stripped portion and the portion with the coating layer is read using a microscope. Then, a graph of displacement δ against load F is created by setting the load F to 10, 20, 30, 50 and 70 gf (i.e., 98, 196, 294, 490 and 686 mN respectively). The primary modulus of elasticity is then calculated using the slope obtained from the graph and the following equation (1). The calculated primary modulus corresponds to the so-called ISM, and will therefore be referred to as P-ISM hereafter. When drawing the colored optical fiber core 3, the drawing speed and ultraviolet irradiance were controlled to adjust the P-ISM. The P-ISM measurement was performed in an atmosphere of 23°C and 50% relative humidity. P-ISM=(3F / δ)*(1 / 2πl)*ln(DP / DG) (Formula 1)

[0024] Here, the unit of P-ISM is [MPa]. Also, F / δ is the slope shown in the graph of displacement (δ) [μm] against load (F) [gf], l is the sample length (e.g., 10 mm), and DP / DG is the ratio of the outer diameter (DP) [μm] of the primary layer 32 to the outer diameter (DG) [μm] of the cladding portion of the optical fiber. Therefore, when calculating P-ISM using the above formula from the F, δ, and l used, it is necessary to perform the required unit conversion. The outer diameter of the primary layer 32 and the outer diameter of the cladding portion can be measured by observing the cross-section of the optical fiber cut with a fiber cutter under a microscope.

[0025] The method for measuring the Young's modulus of the secondary layer 33 is as follows. First, the optical fiber was immersed in liquid nitrogen, and the coating layer of the optical fiber was stripped using a commercially available stripper. A hollow cylindrical sample consisting only of the coating layer was prepared, and the end portion of the sample was fixed to an aluminum plate and conditioned in an atmosphere of 23°C and 50% relative humidity. Next, the aluminum plate portion was chucked using a Tensilon universal tensile testing machine in an atmosphere of 23°C and 50% relative humidity. Then, the sample was pulled at a width of 6 mm, a gauge spacing of 25 mm, and a tensile speed of 1 mm / min, and the force at 2.5% elongation was measured. Based on the measured value, the elastic modulus (secondary modulus) S-ISM (2.5% secant modulus) of the secondary layer 33 was calculated. Although the hollow cylindrical sample also contains the primary layer 32, the S-ISM value is sufficiently large compared to the P-ISM, so the influence of the primary layer 32 was treated as negligible.

[0026] Generally, the Young's modulus of the primary layer 32 can range from 0.1 to 2.0 MPa. The Young's modulus of the secondary layer 33 can range from 500 to 2000 MPa. The Young's modulus of the colored layer 34 can also range from 500 to 2000 MPa.

[0027] Next, we will explain the Young's modulus of ribbon layer 2. Generally, the Young's modulus of ribbon layer 2 can be in the range of 10 to 2000 MPa.

[0028] The method for measuring the Young's modulus of ribbon layer 2 is as follows. First, the ribbon layer 2 on one side of the segmented optical fiber ribbon core 1 (the side where multiple colored optical fiber cores 3 are arranged in parallel) is scraped off using a single-edged blade or similar tool. Then, the remaining colored optical fiber cores 3 along with the ribbon layer 2 are removed from the other side. Next, the ribbon layer 2 is conditioned at a constant temperature and humidity (23°C, 50% constant), and then a 25 mm long sample piece S is prepared. The sample piece S is then pulled at a tensile speed of 1 mm / min, and the Young's modulus at 2.5% strain is calculated. The cross-sectional area of ​​sample piece S was measured using a microscope. Figure 3 is a cross-sectional view showing an example of a sample piece S of ribbon layer 2 used in the test of optical fiber ribbon core 1. Sample piece S contains only the ribbon layer 2. The cross-sectional area of ​​sample piece S was measured using a microscope.

[0029] The storage modulus is the component of energy stored within an object from the energy generated by external force and strain, and represents the elastic element of the material. In this specification, the storage modulus at 150°C is defined as the "equilibrium modulus." The storage modulus and equilibrium modulus of the ribbon layer of the optical fiber ribbon core 1 can be measured by dynamic mechanical analysis (DMA). Dynamic mechanical analysis is the viscoelasticity observed when a periodically changing strain or stress is applied to an object. By measuring dynamic mechanical analysis, data for the storage modulus (G'), loss modulus (G''), and loss tangent (tanδ = G'' / G') can be obtained. Here, the loss modulus represents the viscous element of the material. The loss tangent is the value obtained by dividing the loss modulus by the storage modulus, and represents the balance between the elastic and viscous elements.

[0030] In the case of a perfectly elastic material, stress and strain are proportional, and stress is detected without delay (zero phase difference) in response to the applied stress. On the other hand, in the case of a perfectly viscous material, stress and strain rate are proportional, so when stress is applied as sin(ωt), the response strain is -cos(ωt)=sin(ωt-π / 2), and the strain is detected with a 1 / 4 wavelength delay (phase difference of π / 2) in relation to the stress. The measurement detects the displacement of the sample when an AC force is applied to it. Then, a Fourier simulation is performed on the AC force applied to the sample and the detected displacement to determine the phase difference. General polymers have properties intermediate between perfectly elastic and viscous materials, and the phase difference is between 0 and π / 2. The relationship between stress and strain is measured, and the loss tangent value, which represents the ratio of the storage modulus of the elastic component to the loss modulus of the viscous component, is output. In this specification, the temperature at which the loss tangent value shows a maximum value is defined as the "glass transition temperature".

[0031] In this embodiment, an RSA-G2® manufactured by T.A. Instruments was used as the dynamic viscoelasticity apparatus, and a sample piece S of the ribbon layer 2 was fixed to the tensile jig of the RSA-G2® and measured under the following dynamic viscoelasticity test conditions. <Dynamic viscoelasticity test conditions> Vibration frequency: 1Hz Sample heating rate: 5°C / min

[0032] [Effective core cross-sectional area and microbend loss] Effective core area (Aeff) is an indicator of the likelihood of microbend loss occurring in optical fibers. In this embodiment, the optical fiber has an Aeff of 60 μm. 2 (≧60μm) 2 A fine-grained optical fiber is used. In optical fibers, Aeff is an indicator of microbend sensitivity, and a larger Aeff indicates higher microbend sensitivity. Generally, the effective core cross-sectional area is 100 μm². 2 If it exceeds 130 μm, it is said to have high microbend sensitivity. In particular, Aeff is 130 μm 2 More than 150μm 2The following conditions indicate that the optical fiber has sufficiently high microbend sensitivity. Note that the effective core cross-sectional area (Aeff) refers to the (MFD) 2 This is expressed by the formula ×π×k / 4 (where MFD is the mode field diameter (μm) and k is a constant), and is described, for example, in C-3-76 and C-3-77 of the 1999 IEICE Electronics Society Conference proceedings. Furthermore, Aeff is assumed to be measured at 1550 nm.

[0033] The optical fiber strands and colored optical fiber cores 3 according to this embodiment have a microbend loss of 0.1 dB / km or less.

[0034] Various methods can be considered for measuring microbend loss. In this specification, the value of microbend loss is defined as the difference between the transmission loss of the optical fiber under measurement in the first state, where an optical fiber of 400m or more in length is wound in a single layer without overlapping at a tension of 100gf on a large bobbin wrapped with #1000 grit sandpaper, and the transmission loss of the optical fiber in the second state, which is wound on the same bobbin as the first state with the same tension and length, but without the sandpaper. Here, the transmission loss of the optical fiber in the second state does not include microbend loss and is considered to be the transmission loss inherent to the optical fiber itself.

[0035] This measurement method is similar to the fixed-diameter drum method specified in JIS C6823:2010. This measurement method is also known as the sandpaper method. Furthermore, in this measurement method, the transmission loss is measured at a wavelength of 1550 nm, so the microbend loss in this specification is also a value measured at a wavelength of 1550 nm.

[0036] Figure 4 illustrates the single-core separability of the optical fiber ribbon core 1. Here, the ribbon layer 2 is removed from the optical fiber ribbon core 1, and the state in which one optical fiber ribbon core 1 is separated into four single-core colored optical fiber cores 3 is shown.

[0037] Figure 5 is a schematic diagram of a manufacturing apparatus 5 used in the manufacturing method of the optical fiber ribbon core 1 in this embodiment. The manufacturing apparatus 5 includes a core holding device 51, a guide roller 52, a ribbon layer coating device 53, a guide roller 55, a winding device 56, and a control device 7.

[0038] The core holding device 51 winds up and holds the manufactured colored optical fiber cores 3. The colored optical fiber cores 3 are pulled out from the core holding device 51, guided by guide rollers 52, and transported to the ribbon layer coating device 53. The number of core holding devices 51 and guide rollers 52 may vary depending on the number of colored optical fiber cores 3 contained in the optical fiber ribbon core 1. In this embodiment, the optical fiber ribbon core 1 is manufactured using four colored optical fiber cores 3. Therefore, the number of core holding devices 51 and guide rollers 52 are each four. Each core holding device 51 holds a colored optical fiber core 3, and each guide roller 52 transports the colored optical fiber cores 3 to the ribbon layer coating device 53.

[0039] The ribbon layer coating apparatus 53 includes a resin coating apparatus 531 and an ultraviolet irradiation apparatus 532. The resin coating apparatus 531 holds an ultraviolet-curable resin and applies the ultraviolet-curable resin to the outer circumference of the colored optical fiber core 3. The resin coating apparatus 531 is called a coating die or die. The ultraviolet irradiation apparatus 532 is equipped with any ultraviolet light source 533 such as a metal halide lamp, mercury lamp, or UV-LED light source, and is located downstream of the resin coating apparatus 531 (corresponding to the bottom in Figure 5). The ultraviolet irradiation apparatus 532 is called a curing furnace and irradiates the colored optical fiber core 3 coated with ultraviolet light to form the ribbon layer 2. The UV light source 533 is provided so as to surround the outer circumference of the colored optical fiber core 3. Multiple ultraviolet irradiation apparatuses 532 may be provided in the ribbon layer coating apparatus 53. When multiple ultraviolet irradiation apparatuses 532 are provided, the multiple ultraviolet irradiation apparatuses 532 are provided in series with respect to the transport direction of the colored optical fiber core 3. By providing multiple ultraviolet irradiation devices 532, the irradiation time of the ultraviolet-curable resin can be extended. Furthermore, by measuring the surface temperature of the ribbon layer 2 immediately after ultraviolet irradiation by the UV light source 533 (at the outlet 534 of the ultraviolet irradiation device 532 in Figure 5), the temperature of the ribbon layer 2 immediately after the ultraviolet-curable resin has cured can be measured.

[0040] As the colored optical fiber core 3 passes through the inside of the ultraviolet irradiation device 532, ultraviolet light from the UV light source 533 irradiates the ultraviolet-curable resin coated on the outer circumference of the colored optical fiber core 3. The ultraviolet-curable resin coated on the outer circumference of the colored optical fiber core 3 hardens, forming the ribbon layer 2. The optical fiber ribbon core 1 is transported from the ribbon layer coating device 53 to the winding device 56 via the guide roller 55, where it is wound up.

[0041] The control device 7 controls, for example, the transport speed of the guide rollers 52 and 55, the pressure applied when supplying the UV-curable resin under pressure in the ribbon layer coating device 53, the temperature of the UV-curable resin supplied to the resin coating device 531, the outlet diameter of the ribbon layer coating device 53, the intensity of the UV light source of the UV irradiation device 532, the internal temperature of the ribbon layer coating device 53, and the winding torque of the winding device 56.

[0042] Figure 6 is a block diagram of the control device 7 in this embodiment. The control device 7 includes a CPU (Central Processing Unit) 701, a ROM (Read Only Memory) 702, a RAM (Random Access Memory) 703, a storage device 704, a display 705, a touch sensor 706, an input device 707, a communication interface 708, and a sensor interface 709. Each part is interconnected via a bus 710.

[0043] The CPU 701 controls each part of the manufacturing apparatus 5 using an application program. The ROM 702 consists of non-volatile memory and stores the application program for controlling each part of the manufacturing apparatus 5. The RAM 703 provides the memory area necessary for the operation of the CPU 701. The storage device 704 consists of a hard disk, semiconductor memory, etc.

[0044] The display 705 is composed of, for example, a liquid crystal display, an OLED (Organic Light Emitting Diode) display, an LED (Light Emitting Diode) display, etc. A touch sensor 706 is placed on the surface of the display 705. The touch sensor 706 is equipped with a capacitive or resistive detection circuit. The input device 707 is a user interface and may be, for example, a keyboard, a mouse, etc.

[0045] The communication interface 708 is a communication unit that transmits and receives data, and connects the control device 7 and the ribbon layer coating device 53 in a communicative manner. Communication between the control device 7 and the manufacturing device 5 via the communication interface 708 may be either wired communication or wireless communication. The wireless communication method may be, for example, third-generation mobile communication, LTE (Long Term Evolution), fourth-generation mobile communication, fifth-generation mobile communication, short-range wireless communication such as Bluetooth®, or wireless LAN connection such as Wi-Fi.

[0046] The sensor I / F 709 acquires various data from the sensors provided by the manufacturing apparatus 5 and stores it in the storage device 704, etc. The various data may include, for example, the temperature of the UV-curable resin supplied to the resin coating apparatus 531, the pressure applied when supplying the UV-curable resin under pressure, the temperature of the tank storing the UV-curable resin, the intensity of the UV light source of the UV light source 533, the internal temperature of the ribbon layer coating apparatus 53, the surface temperature of the colored optical fiber core 3, the surface temperature of the optical fiber ribbon core 1, and the surface temperature of the optical fiber ribbon core 1.

[0047] The control device 7 receives control parameters for the manufacturing apparatus 5 through operator input and controls the manufacturing apparatus 5. The control device 7 can also receive information from sensors (not shown) installed in the manufacturing apparatus 5 via the sensor I / F 709 and calculate the transport speed of the guide rollers 52 and 55, the temperature of the tank storing the ultraviolet-curable resin supplied to the resin coating device 531, the surface temperature of the colored optical fiber core 3, the surface temperature of the optical fiber ribbon core 1, the internal temperature of the ribbon layer coating device 53, etc., and reflect these calculations in the control of the manufacturing apparatus 5.

[0048] Figure 7 is a flowchart of the manufacturing method for the optical fiber ribbon core 1 in this embodiment. First, the optical fiber base material is placed in a drawing device (not shown) (step S101). The optical fiber base material is heated with a heater and the bare optical fiber 31 is drawn (step S102). An ultraviolet-curable resin is applied to the outer circumference of the drawn bare optical fiber 31 and irradiated with ultraviolet light to form a primary layer 32 (step S103). An ultraviolet-curable resin is applied to the outer circumference of the primary layer 32 and irradiated with ultraviolet light to form a secondary layer 33 (step S104). Optical fiber strands are obtained through steps S101 to S104. A colored optical fiber core 3 is obtained through steps S101 to S105. The manufactured colored optical fiber core 3 is wound onto a core holding device 51. Steps S101 to S105 are performed for each colored optical fiber core 3.

[0049] The manufacturing apparatus 5 loads the colored optical fiber cores 3 from the core holding device 51 into each of the ribbon layer coating devices 53, and the ribbon layer coating device 53 forms a ribbon layer 2 on the outer circumference of the colored optical fiber cores 3 (step S106). By forming a ribbon layer 2 on the outer circumference of the colored optical fiber cores 3, one optical fiber ribbon core 1 is obtained from four colored optical fiber cores 3. The optical fiber ribbon core 1 is wound onto a bobbin of the winding device 56.

[0050] Figure 8 is a flowchart of the manufacturing method for the ribbon layer 2 in this embodiment. First, the manufacturing apparatus 5 sets the light source output of the UV light source 533, the irradiation time of ultraviolet light to the UV-curable resin, the temperature of the UV-curable resin, etc. (step S201). The output of the UV light source 533 is set in the range of 0 to 100%, with the maximum output of the UV light source 533 being 100%. The irradiation time of ultraviolet light to the UV-curable resin is set by controlling the linear velocity of the colored optical fiber core 3 as it passes through the UV irradiation device 532. Also, as explained in Figure 5, the irradiation time of ultraviolet light to the UV-curable resin can be controlled by providing multiple UV irradiation devices 532. The temperature of the UV-curable resin is set by an operator or the like via the control device 7. The predetermined temperature may be, for example, in the range of 25°C (room temperature) to 50°C.

[0051] The manufacturing apparatus 5 heats the UV-curable resin held in the ribbon layer coating apparatus 53 to a predetermined temperature based on the UV-curable resin temperature set in step S201 (step S202). The UV-curable resin may be heated inside the ribbon layer coating apparatus 53, or it may be heated in a tank (not shown) that houses the UV-curable resin and supplies it to the ribbon layer coating apparatus 53. When applying the UV-curable resin to the colored optical fiber core 3, it is preferable that the UV-curable resin is heated to the temperature set in step S201. The temperature of the UV-curable resin is measured using a thermocouple type thermometer.

[0052] When the UV-curable resin reaches a predetermined temperature, the manufacturing apparatus 5 transports the four colored optical fiber cores 3 wound on the core holding device 51 to the ribbon layer coating device 53. The ribbon layer coating device 53 applies the UV-curable resin to the outer circumference of the colored optical fiber cores 3 in the resin coating device 531 (step S203). Furthermore, the UV irradiation device 532 irradiates the UV-curable resin with UV light for a predetermined irradiation time to form a ribbon layer 2 on the outer circumference of the colored optical fiber cores 3 (step S204). The UV light source provided in the UV irradiation device 532 may be, for example, a metal halide lamp, a mercury lamp, or a UV-LED light source. Examples of wavelengths for the UV-LED light source include 275nm±20nm, 365nm±20nm, 385nm±20nm, and 395nm±20nm.

[0053] Steps S201 to S204 form a ribbon layer 2 on the outer circumference of the colored optical fiber core 3, and one optical fiber ribbon core 1 is obtained from four colored optical fiber cores 3.

[0054] When a cable is made using an optical fiber ribbon core 1 that has become unwinded, excessive load is placed on the optical fiber ribbon core 1, increasing optical loss. Therefore, it is necessary to avoid unwinding on the bobbin during the manufacturing of the optical fiber ribbon core 1. One possible cause of unwinding is friction between the ribbon layers 2 of the optical fiber ribbon core 1. If the frictional force between the ribbon layers 2 is large, the optical fiber ribbon cores 1 will not slide easily when they overlap. As a result, the optical fiber ribbon cores 1 will remain overlapping. Then, when a subsequent optical fiber ribbon core 1 is wound on top of the overlapping optical fiber ribbon cores 1, unwinding may occur.

[0055] To prevent winding collapse, it is necessary to reduce the frictional force between the optical fiber ribbon cores 1. It is generally known that surface friction decreases when the Young's modulus and storage modulus are high. Therefore, in this embodiment, the storage modulus of the ribbon layer 2 is increased in order to reduce the frictional force.

[0056] Furthermore, from the viewpoint of workability at the end of the optical fiber ribbon core 1, the characteristic of separating only the ribbon layer 2 from the colored layer into individual colored optical fiber cores (single-core separability) is required. Maintaining single-core separability requires that the ribbon layer 2 does not break when peeled from the colored layer. For this reason, a high elongation at break of the ribbon layer 2 is required. When the elongation at break is high, the equilibrium modulus tends to be low. Therefore, in this embodiment, the equilibrium modulus of the ribbon layer 2 is lowered. The equilibrium modulus and storage modulus of the ribbon layer 2 can be arbitrarily changed by appropriately adjusting the molecular weight, branching number, functional species, and number of functional groups of the oligomer, the molecular weight, functional species, and number of functional groups of the monomer, and the components and blending ratio of the UV-curable resin composition. For example, increasing the molecular weight of the oligomer can improve the elongation at break, but the storage modulus tends to decrease. Conversely, decreasing the molecular weight of the oligomer reduces its contribution to improving the elongation at break, but it does not significantly decrease the storage modulus. In other words, by appropriately adjusting the molecular weight of the oligomer, it is possible to maintain the storage modulus while also increasing the elongation at break.

[0057] Furthermore, increasing the number of reactive groups (functional groups) involved in the construction of crosslinking structures within the oligomer / monomer structure increases the number of crosslinking points and improves the storage modulus, but tends to decrease the elongation at break. In other words, by appropriately adjusting the number of functional groups involved in the construction of crosslinking structures and combining multiple types of oligomer / monomers, it is possible to maintain the storage modulus while also increasing the elongation at break. In the optical fiber ribbon core 1 of this embodiment, in order to adjust the storage modulus and equilibrium modulus of the ribbon layer 2, one or more types were selected from the oligomer group with a total number-average molecular weight of 1000 to 6000 g / mol. In addition, in order to adjust the storage modulus and equilibrium modulus of the ribbon layer 2, one or more types were selected from the monomer / oligomer group with 1 to 4 reactive groups (functional groups) involved in the construction of crosslinking structures.

[0058] Furthermore, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide was added as a photoinitiator to the UV-curable resin forming ribbon layer 2. Since 2,4,6-trimethylbenzoyl-diphenylphosphine oxide has an absorption region in the 340nm to 420nm wavelength range, the curing reaction proceeds even with long-wavelength UV light. However, the type of photoinitiator is not limited to 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0059] Furthermore, silicone was added as appropriate to the UV-curable resin forming the ribbon layer 2. However, adding too much silicone would reduce the compatibility of the resin, impairing its long-term storage capabilities, or cause partial delamination between the colored layer and the ribbon layer due to silicone bleeding after ribbon core formation; therefore, the type and amount of silicone added could not be too large. In addition, the aforementioned additives such as antioxidants and chain transfer agents were added as needed.

[0060] In this embodiment, the optical fiber ribbon core 1 has an equilibrium modulus of 12.5 MPa or more and 48.3 MPa or less, and a storage modulus of 1210 MPa or more at 25°C. By adjusting the values ​​of the equilibrium modulus and storage modulus of the ribbon layer 2 to satisfy these conditions, an optical fiber ribbon core 1 is provided that can prevent winding collapse during bobbin winding and has high single-core separation properties.

[0061] [Examples] Next, Examples 1-14 and Comparative Example 1-4 of the present invention will be described. The results of the tests in Examples 1-14 and Comparative Example 1-4 are shown in Table 1 below. [Table 1]

[0062] Table 1 shows the equilibrium modulus, storage modulus at 25°C, and glass transition temperature of the ribbon layer 2 of the optical fiber ribbon core 1. Table 1 also shows the evaluation results of the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing. A good winding condition was evaluated as "Good (A)" during manufacturing, while a winding collapse occurred as "Poor (N)".

[0063] Furthermore, Table 1 shows the evaluation results for the single-core separation capability of the optical fiber ribbon core 1. Here, we evaluated whether it was possible to separate a 30cm to 50cm long colored optical fiber core 3 into a single core by cracking the ribbon layer 2 of the optical fiber ribbon core 1 without using special tools and then removing the ribbon layer 2. If there was no peeling or breakage of the colored layer 34 and the colored optical fiber core 3 could be cleanly removed from the ribbon layer 2 without any residue of the ribbon layer 2 remaining on the core, it was evaluated as "Good (A)". However, if single-core separation was possible but the ribbon layer 2 was torn 2 to 4 times or the separation process was time-consuming, it was evaluated as "Acceptable (B)". Also, if peeling or breakage of the colored layer 34 occurred, or if the ribbon layer 2 was torn 5 or more times before a single core was formed, it was evaluated as "Poor (N)".

[0064] [Example 1] In Example 1, a ribbon layer 2 was used with an equilibrium modulus of 20.4 MPa, a storage modulus of 1780 MPa at 25°C, and a glass transition temperature of 55.5°C. In Example 1, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0065] [Example 2] In Example 2, a ribbon layer 2 was used with an equilibrium modulus of 19.5 MPa, a storage modulus of 1900 MPa at 25°C, and a glass transition temperature of 55.9°C. In Example 2, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0066] [Example 3] In Example 3, a ribbon layer 2 was used with an equilibrium modulus of 30.3 MPa, a storage modulus of 2300 MPa at 25°C, and a glass transition temperature of 60.0°C. In Example 3, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0067] [Example 4] In Example 4, a ribbon layer 2 was used with an equilibrium modulus of 33.3 MPa, a storage modulus of 1490 MPa at 25°C, and a glass transition temperature of 60.4°C. In Example 4, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0068] [Example 5] In Example 5, a ribbon layer 2 was used with an equilibrium modulus of 33.7 MPa, a storage modulus of 1820 MPa at 25°C, and a glass transition temperature of 63.7°C. In Example 5, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0069] [Example 6] In Example 6, a ribbon layer 2 was used with an equilibrium modulus of 39.9 MPa, a storage modulus of 2000 MPa at 25°C, and a glass transition temperature of 68.2°C. In Example 6, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0070] [Example 7] In Example 7, a ribbon layer 2 was used with an equilibrium modulus of 13.6 MPa, a storage modulus of 1610 MPa at 25°C, and a glass transition temperature of 106.1°C. In Example 7, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0071] [Example 8] In Example 8, a ribbon layer 2 was used with an equilibrium modulus of 13.3 MPa, a storage modulus of 1500 MPa at 25°C, and a glass transition temperature of 107.1°C. In Example 8, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0072] [Example 9] In Example 9, a ribbon layer 2 was used with an equilibrium modulus of 13.1 MPa, a storage modulus of 1210 MPa at 25°C, and a glass transition temperature of 99.7°C. In Example 9, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0073] [Example 10] In Example 10, a ribbon layer 2 was used with an equilibrium modulus of 12.5 MPa, a storage modulus of 1940 MPa at 25°C, and a glass transition temperature of 100.4°C. In Example 10, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as good (A).

[0074] [Example 11] In Example 11, a ribbon layer 2 was used with an equilibrium modulus of 42.1 MPa, a storage modulus of 1970 MPa at 25°C, and a glass transition temperature of 68.4°C. In Example 11, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as acceptable (B).

[0075] [Example 12] In Example 12, a ribbon layer 2 was used with an equilibrium modulus of 43.7 MPa, a storage modulus of 1240 MPa at 25°C, and a glass transition temperature of 99.3°C. In Example 12, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as acceptable (B).

[0076] [Example 13] In Example 13, a ribbon layer 2 was used with an equilibrium modulus of 44.7 MPa, a storage modulus of 1690 MPa at 25°C, and a glass transition temperature of 66.4°C. In Example 13, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as acceptable (B).

[0077] [Example 14] In Example 14, a ribbon layer 2 was used with an equilibrium modulus of 48.3 MPa, a storage modulus of 1380 MPa at 25°C, and a glass transition temperature of 76.9°C. In Example 14, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), and the single-core separability of the optical fiber ribbon core was evaluated as acceptable (B).

[0078] [Comparative Example 1] In Comparative Example 1, a ribbon layer 2 was used with an equilibrium modulus of 20.2 MPa, a storage modulus of 112 MPa at 25°C, and a glass transition temperature of -52.1°C. In Comparative Example 1, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as poor (N), while the single-core separation of the optical fiber ribbon core was evaluated as good (A).

[0079] [Comparative Example 2] In Comparative Example 2, a ribbon layer 2 was used with an equilibrium modulus of 29.2 MPa, a storage modulus of 154 MPa at 25°C, and a glass transition temperature of -56.9°C. In Comparative Example 2, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as poor (N), while the single-core separation capability of the optical fiber ribbon core was evaluated as good (A).

[0080] In Examples 1-14 and Comparative Examples 1 and 2, bobbin winding was performed while applying a lubricant such as silicone to prevent winding collapse. Normally, when a lubricant is applied, the frictional force in the ribbon layer 2 is reduced, and it is expected that the winding condition will be good. However, in Comparative Examples 1 and 2, the storage modulus of elasticity was set lower than that of the ribbon layer 2 in Examples 1-14, and winding collapse occurred. It was found that in order to prevent winding collapse, it is necessary to set the storage modulus of elasticity of the ribbon layer 2 to a predetermined value or higher.

[0081] [Comparative Example 3] In Comparative Example 3, a ribbon layer 2 was used with an equilibrium modulus of 50.1 MPa, a storage modulus of 970 MPa at 25°C, and a glass transition temperature of 88.8°C. In Comparative Example 3, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), while the single-core separation of the optical fiber ribbon core was evaluated as poor (N).

[0082] [Comparative Example 4] In Comparative Example 4, a ribbon layer 2 was used with an equilibrium modulus of 70.0 MPa, a storage modulus of 1770 MPa at 25°C, and a glass transition temperature of 92.8°C. In Comparative Example 4, the bobbin winding condition of the optical fiber ribbon core 1 during manufacturing was evaluated as good (A), while the single-core separation of the optical fiber ribbon core was evaluated as poor (N).

[0083] Based on the above examples and comparative examples, it was found that when the equilibrium modulus of the ribbon layer 2 is 12.5 MPa or more and 48.3 MPa or less, and the storage modulus of the ribbon layer 2 at room temperature (25°C) is 1210 MPa or more, the bobbin winding condition during manufacturing of the optical fiber ribbon core 1 is good, and an optical fiber ribbon core 1 with high single-core separation is obtained.

[0084] Furthermore, according to the examples and comparative examples, it is more preferable that the equilibrium modulus of the ribbon layer 2 is 12.5 MPa or more and 39.9 MPa or less, and the storage modulus of the ribbon layer 2 at room temperature (25°C) is 1210 MPa or more and 2300 MPa or less.

[0085] Furthermore, according to the examples and comparative examples, it is more preferable for the ribbon layer 2 to have a glass transition temperature of room temperature (25°C) or higher. The reason for adjusting the glass transition temperature of the ribbon layer 2 to be room temperature (25°C) or higher is that if the glass transition temperature of the ribbon layer 2 is below room temperature, the ribbon layer 2 may have a certain degree of stickiness under manufacturing conditions, which will adversely affect the bobbin winding state. It is more preferable for the ribbon layer 2 to have a glass transition temperature of 55.5°C or higher. If the ribbon layer 2 has multiple glass transition temperatures, the highest glass transition temperature should be considered.

[0086] The present invention is not limited to the embodiments described above and can be modified in various ways. For example, an example in which a part of the configuration of one embodiment is added to another embodiment, or in which a part of the configuration of another embodiment is replaced, is also an embodiment of the present invention. Furthermore, for parts that are not specifically described or illustrated in the embodiments, well-known or prior art in the relevant field can be applied as appropriate.

[0087] For example, in the examples and comparative examples, the four-core optical fiber ribbon wire 1 shown in Figure 1 was used, but the structure in Figure 1 is merely one example. Figures 9 and 10 are cross-sectional views of the optical fiber ribbon wire 1 in a modified embodiment. In Figure 9, the shape of the ribbon layer 2 differs from the shape of the ribbon layer 2 shown in Figure 1, with irregularities formed on the surface. In Figure 10, the four colored optical fiber cores are divided into two sets of two, and each set is covered with a tape layer 21 to form two bundled optical fiber ribbon wires. Additionally, the two bundled optical fiber ribbon wires are covered with a bind layer 22 to form a divided optical fiber ribbon wire 1. The tape layer 21 and bind layer 22 shown in Figure 10 are made of ultraviolet-curable resin. The tape layer 21 and bind layer 22 constitute the ribbon layer 2 shown in Figure 1. Even in optical fiber ribbon wires 1 having other structures such as those shown in Figures 9 and 10, the same effects as in the above-described embodiments can be achieved by similarly adjusting the values ​​of the equilibrium modulus and storage modulus in the ribbon layer 2. [Explanation of Symbols]

[0088] 1: Optical fiber ribbon core 2: Ribbon layer 3: Colored fiber optic core

Claims

1. Multiple colored optical fiber cores arranged in parallel, A ribbon layer covering the plurality of colored optical fiber cores and connecting the plurality of colored optical fiber cores, Equipped with, The equilibrium modulus of the ribbon layer is 12.5 MPa or more and 48.3 MPa or less. The storage modulus of the ribbon layer at 25°C is 1210 MPa or more. Optical fiber ribbon core characterized by the following features.

2. The equilibrium modulus is 39.9 MPa or less. The storage modulus is 2300 MPa or less. The optical fiber ribbon core according to feature 1.

3. The ribbon layer has a glass transition temperature of 25°C or higher. The optical fiber ribbon core according to feature 1 or 2.

4. The ribbon layer has a glass transition temperature of 55.5°C or higher. The optical fiber ribbon core according to feature 1 or 2.

5. The steps include arranging multiple colored optical fiber cores in parallel, The steps include: covering the plurality of colored optical fiber cores and forming a ribbon layer that connects the plurality of colored optical fiber cores; Equipped with, The equilibrium modulus of the ribbon layer is 12.5 MPa or more and 48.3 MPa or less. The storage modulus of the ribbon layer at 25°C is 1210 MPa or more. A method for manufacturing optical fiber ribbon cores, characterized by the following features.

6. The equilibrium modulus is 39.9 MPa or less. The storage modulus is 2300 MPa or less. The method for manufacturing an optical fiber ribbon core according to feature 5.

7. The ribbon layer has a glass transition temperature of 25°C or higher. A method for manufacturing an optical fiber ribbon core according to claim 5 or 6.

8. The ribbon layer has a glass transition temperature of 55.5°C or higher. A method for manufacturing an optical fiber ribbon core according to claim 5 or 6.

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