Optical fiber for woven fabric and optical fiber woven fabric

Abstract

The present invention makes it possible to provide an optical fiber for a woven fabric that is less susceptible to defects such as occurrence of bright spots and breakage due to damage to the optical fiber during a manufacturing process for woven fabric using the optical fiber.　An optical fiber (10) for woven fabric, comprising at least one core (1) and a first sheath layer (11) surrounding an outer periphery of the core (1), wherein the bending stiffness of the optical fiber (10) as measured by the KES pure bending test is 0.500 gf·cm2 / yarn or less.

Description

Optical fibers for textiles and optical fiber fabrics

[0001] This invention relates to optical fibers for textiles and optical fiber textiles.

[0002] A plastic optical fiber has a structure in which the outer circumference of a core made of transparent resin is covered with a sheath layer made of a resin with a lower refractive index than the transparent resin. It is a medium that transmits light within the core by totally internalizing the light at the boundary between the core and the sheath layer. Plastic optical fibers are usually used with a coating layer on the outside of the plastic optical fiber to prevent physical and chemical damage. Because light incident from one end of a plastic optical fiber is efficiently transmitted to the other end while undergoing total internalization at the interface between the core and the sheath, it is widely used as a communication medium in industrial and automotive applications.

[0003] In the aforementioned communication medium applications, it is crucial to transmit light from one end to the other without any leakage along the way. On the other hand, if the optical fiber functions as a side-emitting optical fiber, allowing light to leak from the side, it could be used for applications such as indirect lighting inside and outside buildings, or as an alternative to electronic displays. Furthermore, by using these side-emitting optical fibers as constituent yarns in textiles and knitted fabrics, applications such as interior lighting for mobile vehicles like automobiles, trains, and aircraft, as well as decorative lighting, can be expected.

[0004] As fabrics using side-emitting optical fibers as described above, optical fiber fabrics that emit various illumination effects by partially removing the sheath layer of the plastic optical fiber used in the fabric using a grinding wheel, blade, laser heat ray, ultraviolet laser, etc., and allowing light to leak from numerous damaged areas, as well as decorative items using such optical fiber fabrics, have been reported (see, for example, Patent Document 1). Furthermore, a technology has been disclosed for a light-emitting decorative fabric in which at least a portion of the weft is composed of optical fibers having locally distributed light-leading areas in the longitudinal direction, and the warp is composed of metal wires that are more flexible than the optical fibers, and the weft and warp are woven together in a blind weave (see, for example, Patent Document 2). In addition, a technology has been disclosed in which bending at the intersection of the warp and weft and destruction or damage to the cladding layer of the optical fiber are suppressed by arranging at least one auxiliary thread adjacent to the optical fiber (see, for example, Patent Document 3).

[0005] Japanese Patent Publication No. 2006-39287, Japanese Patent Publication No. Hei 6-08700, Japanese Patent Publication No. 2009-084738

[0006] However, as disclosed in Patent Document 2, textiles using optical fibers have the problem that the optical fibers are prone to coming loose from the textile because their surface is smooth. Furthermore, in the textile manufacturing process, tension must be applied to the warp threads during weaving, but the optical fibers may break at the light leakage point under this tension. When such a break occurs, it is virtually impossible to reconnect the broken part, resulting in a defective product and other problems.

[0007] Furthermore, as disclosed in Patent Document 3, at the intersection of warp and weft threads in a woven fabric using optical fibers, the optical fiber bends due to the interference of the opposing warp or weft thread, causing light leakage at this bend and reducing the light guiding efficiency. In addition, due to the characteristics of a woven fabric, the bent optical fiber protrudes from the surface of the fabric, resulting in friction with other fabric surfaces or other material surfaces, which can damage or break the sheath layer of the optical fiber. This increases light leakage and further reduces the light guiding efficiency, which presents a problem.

[0008] Therefore, the present invention aims to provide an optical fiber for textiles that exhibits fewer defects, such as the generation of bright spots or disconnections due to damage to the optical fiber, during the manufacturing process of textiles using optical fibers, and an optical fiber textile using the said optical fiber for textiles.

[0009] The inventors of the present invention conducted diligent research to solve the above-mentioned problems and found that by specifying the bending stiffness in the pure bending measurement of KES to be below a predetermined value in an optical fiber having at least one core and a first sheath layer surrounding the outer circumference of the core, it is possible to reduce the occurrence of bright spots due to damage to the optical fiber and defects such as disconnection during the process of manufacturing the fabric, thus completing the present invention. That is, the present invention is as follows.

[0010] [1] An optical fiber having at least one core and a first sheath layer surrounding the outer circumference of the core, wherein the bending stiffness in the pure bending measurement of KES is 0.500 gf·cm ２[1] An optical fiber for textiles having a yield of / yarn or less. [2] An optical fiber for textiles according to [1], further comprising a second sheath layer surrounding the outer circumference of the first sheath layer. [3] An optical fiber for textiles according to [1] or [2], wherein the core contains a (meth)acrylate resin. [4] An optical fiber for textiles according to any one of [1] to [3], wherein the first sheath layer contains one or more resins selected from the group consisting of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether copolymer, and fluorinated methacrylate polymer. [5] An optical fiber for textiles according to any one of [2] to [4], wherein the second sheath layer contains a tetrafluoroethylene-vinylidene fluoride copolymer. [6] The optical fiber for textiles according to any one of [2] to [5], wherein the first sheath layer contains one or more resins selected from the group consisting of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether copolymer, and fluorinated methacrylate polymer, and the second sheath layer contains tetrafluoroethylene-vinylidene fluoride copolymer. [7] The optical fiber for textiles according to any one of [1] to [6], wherein the outer diameter of the core is 85% or less of the outer diameter of the optical fiber for textiles. [8] The optical fiber for textiles according to any one of [1] to [7], wherein the outer diameter of the optical fiber for textiles is 100 to 300 μm. [9] The optical fiber for textiles according to any one of [1] to [8], wherein the refractive index of the first sheath layer is 1.330 to 1.480.

[10] The optical fiber for textiles according to any one of [2] to [9], wherein the refractive index of the second sheath layer is 1.400 to 1.485.

[11] An optical fiber fabric in which the optical fiber for textiles according to any one of [1] to

[10] is woven as at least a part of the warp and / or weft threads.

[12] The optical fiber fabric according to

[11] , wherein at least a part of the optical fiber for textiles has an exposed region in which the core is exposed.

[13] A fiber optic fabric in which at least a portion of the weft is composed of the optical fiber for weaving described in any one of [1] to

[10] , and other threads other than the optical fiber for weaving constitute the warp threads and are woven together.

[14] The fiber optic fabric according to

[13] , wherein at least a portion of the optical fiber for weaving has an exposed region in which the core is exposed.

[0011] According to the present invention, it is possible to provide an optical fiber for textiles that reduces problems such as the occurrence of bright spots and disconnections due to damage to the optical fiber during the manufacturing process of textiles using optical fibers.

[0012] A schematic cross-sectional view of an example of a single-core optical fiber according to this embodiment is shown. A schematic cross-sectional view of another example of a single-core optical fiber according to this embodiment is shown. A schematic cross-sectional view of an example of a multi-core optical fiber according to this embodiment is shown.

[0013] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"), with reference to the drawings as necessary. However, the present invention is not limited to the embodiments described below. The present invention can be implemented in various modifications within the scope of its gist.

[0014] [Optical Fiber for Textiles] The optical fiber for textiles of this embodiment is an optical fiber having at least one core and a first sheath layer surrounding the outer circumference of the core, wherein the bending stiffness in the pure bending measurement of KES is 0.500 gf·cm ２ It is below / yarn.

[0015] According to the configuration described above, in the manufacturing process of textiles using optical fibers of this embodiment, it is possible to prevent the occurrence of bright spots due to damage to the optical fibers, as well as defects such as disconnections.

[0016] Figure 1 is a schematic cross-sectional view of an example of a textile optical fiber according to this embodiment. The optical fiber 10 is a single-core, single-wire optical fiber, having a core 1 inside and a first sheath layer 11 formed to cover the outer circumference of the core 1. The optical fiber in Figure 1 may also have a predetermined covering layer (not shown) formed to cover the outer circumference of the first sheath layer 11. This protects the optical fiber 10 from long-term use and the effects of chemicals it comes into contact with.

[0017] Figure 2 is a schematic cross-sectional view of another example of the textile optical fiber according to this embodiment. The optical fiber 20 shown in Figure 2 is a single-core, single-wire optical fiber, having a core 1 inside, a first sheath layer 11 formed to cover the outer circumference of the core 1, and a second sheath layer 12 on the outer circumference of the first sheath layer 11. The optical fiber 20 shown in Figure 2 may also have a predetermined covering layer (not shown) formed to cover the outer circumference of the second sheath layer 12. This protects the optical fiber 20 from long-term use and the effects of chemicals it comes into contact with.

[0018] Figure 3 is a schematic cross-sectional view of another example of the textile optical fiber according to this embodiment. The optical fiber 30 shown in Figure 3 is a multi-core, single-wire optical fiber, having a plurality of cores 1 inside, a first sheath layer 11 formed to cover the outer circumference of the cores 1, and a second sheath layer 12 on the outer circumference of the first sheath layer 11. The optical fiber 30 shown in Figure 3 is a 7-core type optical fiber, but the optical fiber of this embodiment is not limited to this configuration, and the number of cores can be selected as appropriate. The optical fiber 30 is made multi-core by covering seven cores 1 with the first sheath layer 11. The optical fiber 30 shown in Figure 3 may further have an outer covering layer (not shown) on the outer circumference of the second sheath layer 12. This makes it possible to more reliably protect the optical fiber from long-term outdoor use and the effects of chemicals it comes into contact with.

[0019] (Bending stiffness in pure bending measurement using KES) The textile optical fiber of this embodiment has a bending stiffness of 0.500 gf·cm in pure bending measurement using KES. ２ The value is less than or equal to / yarn. This improves the softness and smoothness of the optical fiber, and in the manufacturing process of the textile using the optical fiber of this embodiment, it reduces friction and interference between threads other than the optical fiber used as warp or weft threads, or between optical fibers themselves, and effectively prevents defects such as the occurrence of bright spots due to damage to the optical fiber and disconnection. From the above viewpoint, the bending stiffness of the KES in pure bending measurement is 0.490 gf·cm ２ Preferably, it should be less than or equal to / yarn, and 0.480 gf·cm ２It is more preferable that the value is less than or equal to / yarn. Furthermore, the lower limit of the bending stiffness is set to 0.050 gf·cm from the viewpoint of ensuring sufficient strength, such as stiffness and resilience, in the fabric using the optical fiber of this embodiment, and ensuring that it functions sufficiently as a planar light-emitting body. ２ Preferably, it is 0.100 gf·cm² or more. ２ It is more preferable that it be greater than or equal to / yarn.

[0020] In this embodiment, the bending stiffness of the KES in pure bending measurement of the optical fiber for textiles can be controlled to the above-mentioned numerical range by appropriately selecting the outer diameter of the core constituting the optical fiber, the outer diameter of the optical fiber, the material of the sheath layer, the bending stiffness of the sheath layer, and the thickness of the sheath layer, and by adjusting the value of (outer diameter of the core / outer diameter of the optical fiber for textiles). Pure bending measurement of KES can be performed using a KES bending measuring machine. For example, using a KES bending measuring machine (KES-FB2-A manufactured by Kato Tech Co., Ltd.), the curvature is swept in the range of -2.5 to 2.5 / cm, the SENS value (measurement sensitivity) is set to 4 to 50g, and the average value of the slope from -0.5 to -1.5 / cm is taken as the bending stiffness (B value). A larger B value indicates stronger bending stiffness and less bending. Specifically, it can be measured by the method described in the embodiments below.

[0021] (Optical Fiber Configuration) In this embodiment, all existing optical fibers such as silica-based optical fibers, glass-based optical fibers, and plastic-based optical fibers can be used as the optical fiber for textiles, but plastic-based optical fibers are preferred from the viewpoint of flexibility and excellent bending resistance. The outer diameter of the optical fiber for textiles in this embodiment is preferably 300 μm or less from the viewpoint of ease of weaving of warp and weft threads, and preferably 100 μm or more from the viewpoint of ensuring good optical properties and breaking strength to prevent damage in the textile manufacturing process. More preferably 200 to 280 μm, and even more preferably 220 to 270 μm. The bending stiffness of the optical fiber for textiles in this embodiment in the pure bending measurement of KES is 0.500 gf·cm. ２ From the viewpoint of controlling the density to be less than / yarn, a density of 240 μm or less is preferred, and 230 μm or less is more preferred.

[0022] (Core) As the material used for the core 1, any of quartz, glass, and resin materials can be used. However, by forming the core with a resin material, an optical fiber that is flexible and has excellent bending resistance can be obtained. From the perspective of good transparency and low light attenuation of the core resin, an acrylic resin is preferable, and it is preferably included in a (meth)acrylate resin. Examples of the core resin include, but are not limited to, resins with excellent transparency such as polymethyl methacrylate resin (PMMA), polyethyl methacrylate resin (PEMA), polyethyl acrylate resin (PEA), polycarbonate resin, polystyrene resin, and polyolefin resin. These resins may be used alone or in combination of two or more. From the perspective of melt flow (ease of molding), the molecular weight of the acrylic resin is preferably 70,000 to 200,000 as the weight average molecular weight (Mw), and more preferably 80,000 to 120,000.

[0023] (Outer diameter of the core) Regarding the outer diameter of the core, from the perspective of controlling the bending rigidity in the pure bending measurement of the KES of the optical fiber for fabric of this embodiment to 0.500 gf·cm ２ / yarn or less, it is preferable that the ratio of the outer diameter of the core to the outer diameter of the optical fiber for fabric ((outer diameter of the core / outer diameter of the optical fiber for fabric) × 100 (%)) is 85% or less. More preferably, it is 84% or less, and still more preferably, it is 83% or less. On the other hand, from the perspective of manufacturing cost and productivity, 60% or more is preferable, 70% or more is more preferable, and 75% or more is still more preferable. The ratio of the outer diameter of the core to the outer diameter of the optical fiber for fabric can be calculated by (W １ / W ２ ) × 100 (%) in FIG. 1, and by (W ３ / W ４It can be calculated by ) × 100 (%). In a multi-core optical fiber as shown in FIG. 3, it can be calculated by (width of the entire core group / outer diameter of the optical fiber for fabric) × 100 (%). From the above viewpoints, the diameter of the cross-section of the core is preferably 60 μm to 255 μm, more preferably 70 to 252 μm, and even more preferably 75 to 249 μm. If the diameter of the cross-section of the core is 60 μm or more, a practically sufficient optical transmission function can be obtained. Also, if the diameter of the core is 255 μm or less, breakage in the fabric manufacturing process can be prevented, and sufficient optical transmission is possible even in a bent state.

[0024] (First sheath layer) The optical fiber for fabric of the present embodiment surrounds the entire outer periphery of the core 1 with a first sheath layer 11 having a refractive index smaller than that of the material of the core. By providing the first sheath layer 11, light is propagated even when the optical fiber for fabric of the present embodiment is bent due to reflection at the interface between the first sheath layer 11 and the core 1. The material used for the first sheath layer 11 may be any material having a refractive index smaller than that of the core 1, and a resin material is preferable. The smaller the difference in refractive index between the core 1 and the first sheath layer 11, the more light with high frequency and high optical power can be propagated, but there is a tendency to be vulnerable to bending of the optical fiber. On the other hand, the larger the difference in refractive index between the core and the first sheath layer, the stronger it can be against bending of the optical fiber, but there is a tendency for light with a high frequency to be less likely to pass through. From the viewpoint of balancing the characteristics of both the first sheath layer 11 being able to propagate a high-frequency signal and being strong against bending of the optical fiber, the refractive index (n) of the resin of the first sheath layer 11 is preferably 1.330 ≦ n ≦ 1.480, more preferably 1.340 ≦ n ≦ 1.440, and even more preferably 1.350 ≦ n ≦ 1.430.

[0025] The material resin constituting the first sheath layer 11 is not limited to the following, but examples include fluororesins. By using a fluororesin for the first sheath layer 11, a good light transmission function can be obtained. Examples of fluororesins include one or more resins selected from the group consisting of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether copolymer, and fluorinated methacrylate polymer. The fluorinated methacrylate polymer is not limited to the following, but from the viewpoint of high transmittance and excellent heat resistance and moldability, for example, fluorine-containing acrylate monomers or methacrylate monomers such as fluoroalkyl methacrylate, fluoroalkyl acrylate, and α-fluoro-fluoroalkyl acrylate are preferred. Furthermore, it may be a copolymer containing units derived from fluorine-containing (meth)acrylate monomers and units derived from other components copolymerizable with these, and copolymers with units derived from copolymerizable hydrocarbon monomers such as methyl methacrylate are preferred. By using the above-described material as the resin for the first sheath layer 11, it is possible to propagate high-frequency, high-intensity light while ensuring sufficient strength against bending of the optical fiber, and there is a tendency to balance the characteristics of both. Furthermore, by using the above-described material as the resin for the first sheath layer 11, there is a tendency to reduce the bending stiffness in the pure bending measurement of the KES of the optical fiber for textiles of this embodiment. Moreover, from the viewpoint of reducing the bending stiffness in the pure bending measurement of the KES of the optical fiber for textiles of this embodiment, the bending stiffness of the resin for the first sheath layer is set to 100 N・mm ２ ~150000N・mm ２ Preferably, it is 1000 N・mm ２ ~120000N・mm ２ More preferably 1500 N・mm ２ ~80000N・mm ２ That is the case.

[0026] As described above, it is preferable to control the average thickness of the first sheath layer 11 and the ratio of the cross-sectional area of ​​the core to the first sheath layer (core / first sheath layer) so that the value of (outer diameter of the core / outer diameter of the optical fiber for textiles) × 100 (%) is 85% or less. Furthermore, the average thickness of the first sheath layer 11 is preferably 1.0 μm or more from the viewpoint of reducing light leakage and reducing the bending stiffness in the pure bending measurement of the KES of the optical fiber for textiles of this embodiment, and preferably 50 μm or less from the viewpoint of ensuring a sufficient amount of incident light. More preferably it is 1.0 μm to 20 μm, and even more preferably 1.0 μm to 15 μm. The average thickness of the first sheath layer 11 can be controlled to the above numerical range by adjusting the amount of resin in the first sheath layer in the manufacturing process of the optical fiber for textiles of this embodiment, and more specifically, it can be controlled to the above numerical range by adjusting the amount of core resin and the amount of resin in the first sheath layer in the core resin distribution chamber and the sheath resin distribution chamber in the manufacturing process of the optical fiber for textiles.

[0027] (Second Sheath Layer) The textile optical fiber of this embodiment may have a second sheath layer 12 surrounding the outer circumference of the first sheath layer 11, as shown in Figure 2. The second sheath layer 12 has the function of protecting the textile optical fiber of this embodiment and maintaining abrasion resistance and mechanical strength. The second sheath layer 12 is made of a material with a refractive index smaller than that of the first sheath layer 11, and from the viewpoint of reflecting light leaked from the first sheath layer 11 at the outermost layer and efficiently propagating light, it is preferable that the refractive index (N) of the resin of the second sheath layer 12 is 1.400 ≤ N ≤ 1.485. More preferably it is 1.401 to 1.484, and even more preferably 1.402 to 1.483.

[0028] The material of the second sheath layer 12 may be any material different from the material of the first sheath layer 11, and there is no particular limitation. However, as a preferable example, a fluororesin having strong adhesion to the resin of the first sheath layer can be mentioned. Such fluororesins include fluororesins applicable to the first sheath layer 11 described above and different from the resin constituting the first sheath layer 11, and preferably include tetrafluoroethylene-vinylidene fluoride copolymers. In particular, when the first sheath layer 11 contains one or more resins selected from the group consisting of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether copolymer, and methacrylate fluoride polymer, it is preferable for the second sheath layer 12 to contain a tetrafluoroethylene-vinylidene fluoride copolymer from the viewpoint of reducing the mechanical strength and bending rigidity of the optical fiber for fabric. Further, by using the above-described materials as the resin of the second sheath layer 12, there is a tendency to reduce the bending rigidity in the pure bending measurement of KES of the optical fiber for fabric of the present embodiment. Furthermore, from the viewpoint of reducing the bending rigidity in the pure bending measurement of KES of the optical fiber for fabric of the present embodiment, the bending rigidity of the resin for the second sheath layer is 100 N·mm ２ to 150000 N·mm ２ is preferable, more preferably 1000 N·mm ２ to 120000 N·mm ２ , still more preferably 1500 N·mm ２ to 80000 N·mm ２ is.

[0029] Furthermore, a non-fluororesin other than the fluororesin mentioned above can be used as the resin for the second sheath layer 12. As the non-fluororesin, for example, an acrylic resin is preferred from the viewpoint of mechanical strength. The resin for the second sheath layer 12 may be used alone or two or more types may be used in combination. Polymethyl methacrylate resins are particularly preferred. A polymethyl methacrylate resin refers to a homopolymer of methyl methacrylate, or a copolymer containing 50% by mass or more of a methyl methacrylate component. The polymethyl methacrylate resin may be a copolymer containing methyl methacrylate and a component copolymerizable with methyl methacrylate. The component copolymerizable with methyl methacrylate is not limited to the following, but examples include acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate; methacrylic acid esters such as ethyl methacrylate, propyl methacrylate, and cyclohexyl methacrylate; maleimides such as isopropyl maleimide, acrylic acid, methacrylic acid, styrene, etc. These copolymerizable components may be used individually or in combination of two or more. From the viewpoint of melt flow (ease of molding), the molecular weight of the acrylic resin used as the resin for the second sheath layer 12 is preferably 80,000 to 200,000 as a weight-average molecular weight (Mw), and more preferably 90,000 to 120,000.

[0030] As described above, it is preferable to control the average thickness of the second sheath layer 12 so that the value of (outer diameter of the core / outer diameter of the optical fiber for textiles) × 100 (%) is 85% or less. From the viewpoint of maintaining the mechanical strength of the optical fiber for textiles of this embodiment and from the viewpoint of reducing the bending stiffness in the pure bending measurement of the optical fiber for textiles of this embodiment, it is preferable that the average thickness of the second sheath layer 12 be 1.0 μm or more, and from the viewpoint of ensuring a sufficient amount of incident light, it is preferable that it be 50 μm or less. More preferably it is 2.0 μm to 20 μm, and even more preferably it is 4.0 μm to 15 μm. The average thickness of the second sheath layer 12 can be controlled to the above numerical range by adjusting the amount of resin in the second sheath layer in the manufacturing process of the optical fiber for textiles of this embodiment, and more specifically, it can be controlled to the above numerical range by adjusting the amount of resin in the second sheath layer in the sheath resin distribution chamber in the manufacturing process of the optical fiber for textiles.

[0031] (Coating layer) The optical fiber for textiles in this embodiment may have an additional predetermined coating layer on the outside of the first coating layer 11 or the second coating layer 12.

[0032] The constituent material of the coating layer is not particularly limited, but from the viewpoint of protecting the textile optical fiber of this embodiment, a resin with excellent mechanical strength and a flame-retardant resin are preferred, and a resin with excellent mechanical strength is particularly preferred. Examples of resins with excellent mechanical strength are, but are not limited to, polyamide resins, polyethylene resins, polypropylene resins, polyvinylidene fluoride resins, etc. These tend to be able to protect the textile optical fiber from external forces such as lateral pressure and also have the effect of mitigating external impacts. The resin constituting the coating layer preferably has sufficient strength to protect from external forces, and a resin with a tensile yield strength (JIS K7113) of about 20 MPa or higher is particularly preferred. Examples of resins with such strength include polyamide 12 resins, crosslinked polyethylene resins, crosslinked polyethylene resins, and polypropylene resins. On the other hand, as a flame-retardant resin, it is preferable that it is made of a resin composition that meets the UL VW-1 standard. By using such a resin composition in the coating layer, a textile optical fiber that can be used in high-temperature environments can be obtained. It is presumed that meeting the UL VW-1 standard is useful in preventing the deterioration of transmission loss in high-temperature environments, as follows: In other words, resins with high flame retardancy are generally presumed to have high heat resistance, and it is thought that having sufficient flame retardancy to meet this standard contributes to improving the heat resistance of optical fibers. For this reason, it is preferable that the resin material constituting the coating layer used in the textile optical fiber of this embodiment meets the UL VW-1 standard.

[0033] Examples of resin materials used for the coating layer include polyethylene resins, flame-retardant polyethylene resins, polyamide resins, vinyl chloride resins, and fluororesins such as polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymer (ETFE), and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA); and silicone resins. In particular, flame-retardant polyethylene resins, which are obtained by compounding a flame retardant with polyethylene resin to impart flame retardancy, are preferred from the viewpoint of environmental consideration as they do not contain halogens. Flame-retardant polyethylene resins are not limited to the following, but are preferably those containing (A) at least one copolymer selected from the group consisting of ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer, (B) high-density polyethylene modified with an unsaturated carboxylic acid or its derivative, (C) magnesium hydroxide, and (D) red phosphorus. Furthermore, from the viewpoint of further improving flame retardancy, it is more preferable to include (E) melamine isocyanurate. In addition, from the viewpoint of improving heat resistance, polyamide resins are preferred. Examples of polyamide resins include polyamide 66 resin, polyamide 6 resin, polyamide 11 resin, polyamide 12 resin, and polyamide 10-10 resin. Among these, polyamide 11 resin and polyamide 12 resin are preferred due to their excellent heat resistance. Furthermore, polyamide 10-10 resin can be manufactured from plant-based raw materials such as castor oil, which is preferable from the viewpoint of reducing carbon dioxide emissions.

[0034] (Other Components) Each part constituting the optical fiber for textiles of this embodiment may further contain predetermined additives, to the extent that they do not impair the effects of this embodiment. Such additives can be selected according to the purpose of use and are not limited to the following, but examples include colorants such as carbon black, antioxidants, ultraviolet absorbers, light stabilizers, metal deactivators, lubricants, flame retardants other than those mentioned above, flame retardant aids, fillers, etc. An example of using additives is adding carbon black to the first sheath layer, second sheath layer, and coating layer for the purpose of preventing light leakage from the optical fiber.

[0035] (Other configurations) As described above, the optical fiber for textiles of this embodiment has one or more cores and a first sheath layer formed on the outer circumference of the cores. The optical fiber for textiles of this embodiment may further have a second sheath layer and a coating layer, and the number of wires can be selected as appropriate.

[0036] [Method for Manufacturing Optical Fibers for Textiles] The method for manufacturing optical fibers for textiles in this embodiment is not particularly limited and can be carried out by known methods. For example, they can be manufactured by known composite spinning methods, and a coating layer made of the polyethylene resin, polyvinyl chloride, polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and silicone resin, which are heat-melted by a crosshead die, may be formed on the outside of the optical fiber.

[0037] [Optical Fiber Fabric] In this embodiment, the optical fiber fabric is woven in such a way that the optical fiber for weaving described above is incorporated as at least a portion of the warp and / or weft threads. Alternatively, in this embodiment, the optical fiber fabric may be such that the optical fiber for weaving described above constitutes at least a portion of the weft threads, and other threads other than the optical fiber for weaving constitute the warp threads. As the other threads, a material with greater flexibility than the optical fiber for weaving described above, such as a metal wire, can be used. According to this embodiment, the optical fiber fabric can effectively suppress the breakage and damage of the optical fiber at the intersection of the warp and weft threads.

[0038] The optical fiber fabric of this embodiment may have an exposed region in at least a part of the optical fiber fabric in which the core is exposed. In the exposed region, the surface shape of the exposed core is formed to conform to the interface between the core and the sheath layer. The optical fiber fabric of this embodiment allows for the arrangement of multiple optical fibers in a planar manner, and the removal of the sheath layer in each optical fiber to be arranged in two dimensions. By using a light-emitting means to inject light into each optical fiber, various patterns and characters can be displayed by leaking light from the exposed portion of the core.

[0039] The core exposure area can be formed using an ultraviolet laser. Specifically, by irradiating an optical fiber fabric containing optical fibers with a core and sheath layer mainly composed of acrylic resin with an ultraviolet laser having a wavelength in the range of 190 nm to 355 nm to remove the sheath layer, the ultraviolet laser is irradiated while the optical fibers are still attached to the optical fiber fabric, allowing for precise positioning and processing of the areas where the sheath layer is removed. Therefore, even when forming areas where the sheath layer is removed to create two-dimensional patterns, the desired patterns, characters, and designs can be easily processed by positioning the ultraviolet laser in accordance with the pattern.

[0040] Furthermore, since the optical fiber fabric itself serves as the display element in this embodiment, it can be made into a thin and flexible display element. In addition, by using multiple light-emitting means that emit different colors, multi-color display is also possible.

[0041] By placing the optical fiber fabric of this embodiment on the back of a liquid crystal substrate and equipping a liquid crystal display device with light-emitting means for irradiating the optical fibers of the optical fiber fabric with light, it can also be used as a backlight to illuminate the liquid crystal substrate almost uniformly from the back. Furthermore, if the liquid crystal substrate is flexible, the backlight function can be easily added without impairing the flexibility of the liquid crystal substrate.

[0042] (Applications) The optical fiber fabric of this embodiment is suitable for applications such as clothing, accessories, interior goods, indoor and outdoor decorations, information boards, bulletin boards, signs and other display devices, and liquid crystal display devices. In particular, it is useful for textile products (jackets, coats, sportswear, shoes, etc.), sports goods, accessories (bags, hats, belts, hoodies, umbrellas, etc.), household goods (curtains, tents, velours, covers), automotive products (interior decorations), and safety products (clothing for police officers and rescue workers, clothing for professional technicians, safety flags for automobiles, truck tents, automobile covers, etc.).

[0043] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. The physical properties used in this specification, and the evaluated physical properties evaluated in the examples and comparative examples described later, are measured and evaluated using the methods shown below, respectively.

[0044] [Measurement of Physical Properties of Plastic Optical Fibers] (Measurement of KES Bending Stiffness) The bending stiffness of plastic optical fibers, which were fabricated as described below for use in textiles, was measured using a KES-FB2-A pure bending tester manufactured by Kato Tech. Twenty plastic optical fibers were cut to 6 cm lengths, and measurement samples were prepared by sequentially stretching the optical fibers in parallel at 1 mm intervals with the same tension. The maximum curvature was set to 2.5 / cm, the SENS value was set to 50 g, and each fiber was measured five times. The average value was calculated as the bending stiffness B value.

[0045] (Bending stiffness of the sheath layer material) The material of the sheath layer used in the fabrication of plastic optical fibers, as described later, was used as the measurement target. The sheath layer material was molded to a size of 10 mm (width) x 4 mm (thickness) x 80 mm (length) to form a test specimen. The bending modulus E (Pa) was measured in accordance with ISO 178. The bending stiffness was expressed as the bending modulus E (Pa) of the test specimen and the second moment of area I (m ４ The bending stiffness (N・m) was calculated from the following formula: ２ )=E(Pa)×I(m ４ Furthermore, since the cross-section of the test specimen is rectangular, the second moment of area I of the rectangular cross-section is I = bh, where b (m) is the width of the test specimen and h (m) is the thickness. ３ / 12 (m ４ ) was assumed to be the case.

[0046] [Evaluation of the properties of plastic optical fibers] (Measurement of the breaking strength of plastic optical fibers) Tensile tests were conducted on plastic optical fibers fabricated as described below using a Shimadzu Autograph AGS-X. The tests were performed on a 175 mm plastic optical fiber at a test speed of 100 mm / min and a gripping distance of 100 mm. The load at the time of breakage was defined as the breaking strength (N), and the following evaluation criteria were used for evaluation. <Evaluation criteria> ○: Breaking strength of 6 N or more ×: Breaking strength less than 6 N

[0047] (Evaluation of defects such as bright spots and disconnections in the weaving process) Using a rapier weaving machine (manufactured by Itema Weaving Co.), optical fibers and polyester fibers were spun and woven. The occurrence of defects such as bright spots due to yarn damage and disconnections in the weaving process was checked and evaluated according to the following evaluation criteria. <Evaluation Criteria> ○: Defect occurrence rate is less than 10% ×: Defect occurrence rate is 10% or more

[0048] [Fabrication of Plastic Optical Fibers] (Materials) The following materials were used as the sheath material for the sheath layer constituting the optical fiber for textiles. Sheath material A: Tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (refractive index 1.350) Sheath material B: Ethylene-tetrafluoroethylene copolymer (refractive index 1.385) Sheath material C: Tetrafluoroethylene-vinylidene fluoride copolymer (refractive index 1.400) Sheath material D: Tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether copolymer (refractive index: 1.352) Sheath material E: Fluorinated methacrylate copolymer (refractive index 1.418) Sheath material F: Fluorinated methacrylate copolymer (refractive index 1.462)

[0049] [Example 1] Using sheath material A for the first sheath layer and sheath material C for the second sheath layer, and using polymethyl methacrylate (refractive index 1.491) as the core material, melt spinning was performed using a composite spinning machine to obtain a plastic optical fiber with a fiber diameter of 254 μm. The amount of sheath layer material supplied to the composite spinning machine was adjusted so that the sum of the thicknesses of the first and second sheath layers ((thickness of the first sheath layer + thickness of the second sheath layer) × 2) was 52 μm. Using the fabricated plastic optical fiber, an optical fiber fabric was made using a rapier weaving machine (manufactured by Itema Weaving Co., Ltd.), evaluated using the evaluation method described above, and the results are shown in Table 1.

[0050] [Example 2, Comparative Example 1] The total thickness of the first and second sheath layers was changed as shown in Table 1. The core outer diameter was also changed as shown in Table 1. Plastic optical fibers and optical fiber fabrics were manufactured under the same conditions as in Example 1.

[0051] [Example 3] Using sheath material E for the first sheath layer and sheath material C for the second sheath layer as the sheath layer material, and polymethyl methacrylate (refractive index 1.491) as the core material, melt spinning was performed using a composite spinning machine to obtain a plastic optical fiber with a fiber diameter of 253 μm. The amount of sheath layer material supplied to the composite spinning machine was adjusted so that the sum of the thicknesses of the first and second sheath layers ((thickness of the first sheath layer + thickness of the second sheath layer) × 2) was 37 μm. Using the fabricated plastic optical fiber, an optical fiber fabric was made using a rapier weaving machine (manufactured by Itema Weaving Co., Ltd.), evaluated using the evaluation method described above, and the results are shown in Table 1.

[0052] [Example 4, Comparative Example 2] The total thickness of the first and second sheath layers was changed as shown in Table 1. The core outer diameter was also changed as shown in Table 1. Plastic optical fibers and optical fiber fabrics were manufactured under the same conditions as in Example 3.

[0053] [Example 5] Using sheath material D for the first sheath layer and sheath material C for the second sheath layer as the sheath layer material, and using polymethyl methacrylate (refractive index 1.491) as the core material, melt spinning was performed using a composite spinning machine to obtain a plastic optical fiber with a fiber diameter of 201 μm. The amount of sheath layer material supplied to the composite spinning machine was adjusted so that the sum of the thicknesses of the first and second sheath layers ((thickness of the first sheath layer + thickness of the second sheath layer) × 2) was 19 μm. Using the fabricated plastic optical fiber, an optical fiber fabric was made using a rapier weaving machine (manufactured by Itema Weaving Co., Ltd.), evaluated using the evaluation method described above, and the results are shown in Table 1.

[0054] [Example 6] As the material for the sheath layer, sheath material C was used for the first sheath layer, and a second sheath layer was not formed. Polymethyl methacrylate (refractive index 1.491) was used as the core material, and melt spinning was performed using a composite spinning machine to obtain a plastic optical fiber with a fiber diameter of 175 μm. The amount of sheath layer material supplied to the composite spinning machine was adjusted so that the sum of the thicknesses of the first and second sheath layers ((thickness of the first sheath layer + thickness of the second sheath layer) × 2) was 12 μm. Using the fabricated plastic optical fiber, an optical fiber fabric was made using a rapier weaving machine (manufactured by Itema Weaving Co., Ltd.), evaluated using the evaluation method described above, and the results are shown in Table 1.

[0055] [Comparative Example 3] As the material for the sheath layer, sheath material B was used for the first sheath layer, no second sheath layer was formed, and polymethyl methacrylate (refractive index 1.491) was used as the core material. Melt spinning was performed using a composite spinning machine to obtain a plastic optical fiber with a fiber diameter of 250 μm. The amount of sheath layer material supplied to the composite spinning machine was adjusted so that the total thickness of the first sheath layer (thickness of the first sheath layer × 2) was 12 μm. Using the fabricated plastic optical fiber, an optical fiber fabric was made using a rapier weaving machine (manufactured by Itema Weaving Co., Ltd.), evaluated using the evaluation method described above, and the results are shown in Table 1.

[0056] [Comparative Example 4] As the material for the sheath layer, sheath material C was used for the first sheath layer, no second sheath layer was formed, and polymethyl methacrylate (refractive index 1.491) was used as the core material. Melt spinning was performed using a composite spinning machine to obtain a plastic optical fiber with a fiber diameter of 250 μm. The amount of sheath layer material supplied to the composite spinning machine was adjusted so that the total thickness of the first sheath layer (thickness of the first sheath layer × 2) was 10 μm. Using the fabricated plastic optical fiber, an optical fiber fabric was made using a rapier weaving machine (manufactured by Itema Weaving Co., Ltd.) and evaluated using the evaluation method described above. The results are shown in Table 1.

[0057] [Comparative Example 5] Using sheath material F for the first sheath layer and sheath material C for the second sheath layer as the sheath layer material, and using polymethyl methacrylate (refractive index 1.491) as the core material, melt spinning was performed using a composite spinning machine to obtain a plastic optical fiber with a fiber diameter of 253 μm. The amount of sheath layer material supplied to the composite spinning machine was adjusted so that the sum of the thicknesses of the first and second sheath layers ((thickness of the first sheath layer + thickness of the second sheath layer) × 2) was 37 μm. Using the fabricated plastic optical fiber, an optical fiber fabric was made using a rapier weaving machine (manufactured by Itema Weaving Co., Ltd.), evaluated using the evaluation method described above, and the results are shown in Table 1.

[0058] [Comparative Example 6] Using sheath material C for the first sheath layer and sheath material F for the second sheath layer as the sheath layer material, and using polymethyl methacrylate (refractive index 1.491) as the core material, melt spinning was performed using a composite spinning machine to obtain a plastic optical fiber with a fiber diameter of 253 μm. The amount of sheath layer material supplied to the composite spinning machine was adjusted so that the sum of the thicknesses of the first and second sheath layers ((thickness of the first sheath layer + thickness of the second sheath layer) × 2) was 37 μm. Using the fabricated plastic optical fiber, an optical fiber fabric was made using a rapier weaving machine (manufactured by Itema Weaving Co., Ltd.), evaluated using the evaluation method described above, and the results are shown in Table 1.

[0059]

[0060] Comparative Examples 1-6 showed a bending stiffness of 0.500 gf·cm in the pure bending measurement using KES. ２Because it was greater than / yarn, it was confirmed that a problem occurred in the weaving process. On the other hand, in Examples 1 to 6, the bending stiffness in the pure bending measurement of KES was 0.500 gf・cm ２ Because the yield was less than / yarn, the defect rate in the weaving process was low and favorable.

[0061] This application is based on Japanese Patent Application No. 2024-207298, filed with the Japan Patent Office on November 28, 2024, the contents of which are incorporated herein by reference.

[0062] The textile optical fiber of the present invention has industrial applicability as a material for clothing, accessories, interior goods, indoor and outdoor decorations, display devices such as signboards, bulletin boards, and billboards, and light-emitting decorative items such as liquid crystal display devices.

[0063] 1 core 11 first sheath layer 12 second sheath layer W １ , W ３ Core outer diameter W ２ , W ４ Outer diameter of optical fiber W ２ -W １ Sum of the thicknesses of the first sheath layer W ４ -W ３ Sum of sheath layer thicknesses: 10, 20, 30; Optical fibers for textiles

Claims

1. An optical fiber having at least one core and a first sheath layer surrounding the outer circumference of the core, wherein the bending stiffness in a pure bending measurement using KES is 0.500 gf·cm ２ Optical fibers for textiles, with a length of / yarn or less.

2. The optical fiber for textiles according to claim 1, further comprising a second sheath layer surrounding the outer periphery of the first sheath layer.

3. The optical fiber for textiles according to claim 1, wherein the core contains a (meth)acrylate resin.

4. The optical fiber for textiles according to claim 1, wherein the first sheath layer comprises one or more resins selected from the group consisting of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether copolymer, and fluorinated methacrylate polymer.

5. The optical fiber for textiles according to claim 2, wherein the second sheath layer comprises a tetrafluoroethylene-vinylidene fluoride copolymer.

6. The optical fiber for textiles according to claim 2, wherein the first sheath layer contains one or more resins selected from the group consisting of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether copolymer, and fluorinated methacrylate polymer, and the second sheath layer contains tetrafluoroethylene-vinylidene fluoride copolymer.

7. The optical fiber for textiles according to claim 1, wherein the outer diameter of the core is 85% or less of the outer diameter of the optical fiber for textiles.

8. The optical fiber for textiles according to claim 1, wherein the outer diameter of the optical fiber for textiles is 100 to 300 μm.

9. The optical fiber for textiles according to claim 1, wherein the refractive index of the first sheath layer is 1.330 to 1.

480.

10. The optical fiber for textiles according to claim 2, wherein the refractive index of the second sheath layer is 1.400 to 1.

485.

11. A fiber optic fabric in which the optical fiber for textiles described in any one of claims 1 to 10 is woven as at least part of the warp and / or weft threads.

12. The optical fiber fabric according to claim 11, wherein at least a portion of the optical fiber for the fabric has an exposed region in which the core is exposed.

13. A fiber optic fabric in which at least a portion of the weft threads are composed of the fiber optics for weaving described in any one of claims 1 to 10, and other threads other than the fiber optics for weaving constitute the warp threads and are woven into the fabric.

14. The optical fiber fabric according to claim 13, wherein at least a portion of the optical fiber for the fabric has an exposed region in which the core is exposed.

Images