JPH06331830A - Cable for light emission from flank - Google Patents

Abstract

PURPOSE:To enable soft and uniform light emission without unequalness in the light emission from a flank by arranging the bare wire of a plastic optical fiber made of a core consisting of a resin mainly composed of methyl methacrylate and a sheath consisting of a resin mainly composed of vinylidene fluoride in a light diffusing layer. CONSTITUTION:An opaque mixture composed of a silicone elastomer of a thermoplasticizer and a polyolefin resin of a light diffusing material is used as the resin for forming the light diffusing layer 4. The core polymer 1 of the plastic optical fiber consists of the resin mainly composed of the methacrylic acid and the sheath polymer 2 consists of the resin mainly composed of the vinylidene fluoride as the high mechanical strength of the plastic optical fiber is demanded. A hindered amine optical stabilizer of >=2000 number average mol.wt. which is high polymered is used as the optical stabilizer, by which the coloration of the plastic optical fiber is lessened and the weatherability of the light diffusing layer is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side-emission fiber suitable for illumination, in which light incident on the end face of the fiber is leaked from the side face of the fiber to show the shape or existence of an object, or the destination and the like. It is used for indicating the direction and for decoration.

[0002]

2. Description of the Related Art As a method of emitting light linearly or in a plane over a relatively long distance, there are many side emission techniques using a plastic optical fiber. These techniques include mechanically scratching the interface between the core and the sheath of the plastic optical fiber, or by partially dissolving the interface with a solvent to leak the light, or bending the plastic optical fiber to release the light. A leaking method, a plastic optical fiber woven fabric, a planar light emitting device in which a semi-transparent light scattering film layer is adhered to one side thereof, a bare plastic optical fiber bundle that is inserted into a transparent hose, etc. is there.

When it is desired to widen the light emitting surface for emitting light, there is usually a method of arranging a plurality of plastic optical fibers on a plane, or arranging the plastic optical fibers with different thicknesses and widths for side light emission. No. 247705.

[0004]

Among the side surface light emitters according to the prior art, the one in which the cladding of the plastic optical fiber is damaged has the mechanical strength of the plastic optical fiber lowered and a uniform damage. Because it is difficult to
The problem is that the light emission becomes uneven and lacks elegance. When a plastic optical fiber is bent or made into a woven fabric, the light shines strongly at the bend, so it has a special taste, so depending on the taste of the user, that taste may be used. is there. However, its use is limited because it is not a light emitter that emits uniform light. In the case where multiple commercially available plastic optical fibers are inserted into a transparent plastic hose, the plastic optical fibers are intricately overlapped and twisted in the hose, and since they are transparent hose, uneven light emission is noticeable .

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a hose-shaped product made of a material obtained by adding a polymerized hindered amine-based light stabilizer to an opaque resin composed of a polyolefin resin and a thermoplastic silicone elastomer. A side emitting cable in which a bare layer of a plastic optical fiber having a core made of a resin mainly composed of methyl methacrylate and a sheath made of a resin mainly composed of vinylidene fluoride is disposed as a diffusion layer.

The cable of the present invention is a plastic optical fiber cable coated with an opaque resin having a light diffusive property, and is a side light emitting cable which emits light evenly from the side surface and emits soft and uniform light. . In particular, when only one bare bare plastic optical fiber is placed inside, the light emission from the side becomes more uniform, and when laying the cable, the cable is curved with a smooth curve like a universal ruler. Because it bends, it enables an elegant light emission. The thickness of the bare wire of the plastic optical fiber can be generally 0.5 mm to 3.5 mm when arranging a plurality of bare wires, but when arranging only one bare wire. A diameter of about 2.0 mm to 5.0 mm is suitable.
If it is less than 2.0 mm, the amount of light emission is insufficient. Brightness increases as the thickness increases, but rigidity increases, so it is preferable to select the thickness according to the application. When only one bare optical fiber with a diameter of 2 mm or more is covered with a light diffusing layer, the outside of the bare plastic optical fiber is made of an opaque resin having a light diffusing property and has a thickness of 0.1 mm or more. Needs to be covered. A gap is required between this diffusion layer and the bare plastic optical fiber. It is necessary that 20% or more of the entire circumference of the bare plastic optical fiber has a clearance of 100 μm or more. If there is no gap and the bare wire of the plastic optical fiber and the diffusion layer are in close contact with each other, for example, when a rigid plastic optical fiber with a large diameter is bent, contact between the bare plastic optical fiber and the diffusion layer This is because stress due to misalignment at the portion causes excessive light leakage, resulting in a defect that the portion becomes extremely bright. By providing a gap here, the bare plastic optical fiber can easily slip with the diffusion layer and suppress optical loss due to bending. The light diffusion layer may be a single layer or a multilayer. The coating layer outside the plastic optical fiber bare wire is generically called a light diffusion layer.

In the present invention, an opaque mixture with at least a polyolefin resin using a silicone elastomer as a light diffusing material as a light diffusing material is used as the resin forming the light diffusing layer. The thermoplastic silicone elastomer is a polyorganosiloxane grafted with polyethylene or ethylene copolymer. Examples of such resins commercially available include those commercialized under the name of SIGLRAFT as products of Nippon Unicar Co., Ltd. When the sheet is irradiated with white light from the back side of a sheet made of a mixture of such a thermoplastic silicone elastomer and polyethylene or a mixture of ethylene and vinyl acetate copolymer, ethylene and ethyl acrylate copolymer or polyolefin resin such as polypropylene, the sheet This is because it has been found that it is a resin suitable for a light diffusion layer, which itself is bright and vivid, shines white like a fluorescent lamp, and is transparent and invisible.

It is essential that the resin constituting the light diffusing layer of the present invention is a mixture of the above-mentioned thermoplastic silicone elastomer and polyolefin resin.
In some cases, the present invention includes a coating layer made of other transparent, translucent, or opaque resin. These resins include polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyolefin resin such as polypropylene, polyvinyl chloride resin, thermoplastic polyurethane resin, styrene / butadiene block copolymer elastomer. Hydrogenated most of the double bonds of this copolymer, vinylidene fluoride and hexafluoropropene copolymer, vinylidene fluoride and hexafluoropropene and tetrafluoroethylene copolymer, vinylidene fluoride and chloro Examples thereof include trifluoroethylene copolymer, but are not limited to these lengths.

A light diffusing layer made of a mixture of a thermoplastic silicone elastomer and a polyolefin resin is preferably used as the outermost layer, and this light diffusing layer leaks from a plastic optical fiber bare wire. It becomes a soft luminous body that diffuses light and is evenly leveled. The light diffusion layer may be lightly colored if desired. The thickness of the light diffusion layer is required to be at least 0.1 mm in order to maintain mechanical strength and to softly diffuse the light of the internal plastic optical fiber bare wire. More preferable thickness is 0.4
It is about mm to about 1.5 mm. The outer diameter of the cable may be about 2 mm to 15 mm depending on the intended use. The light diffusion layer is opaque, but the term opaque here means that the inside is opaque and opaque. The degree of turbidity and thickness of the resin in the light diffusion layer must be considered synergistically. To reduce the thickness, the turbidity of the resin must be thick, and to increase the thickness, the turbidity of the resin must be thin. There is. As a preferable requirement for this light diffusion layer, a sheet molded to the thickness of the light diffusion layer actually used may be confirmed in advance by the following evaluation method. That is, the sample sheet is irradiated with a laser beam (for example, a He-Ne laser beam of 2 mm) at a right angle, and the intensity of the light emitted from the back side is measured with respect to the angle with respect to the incident optical axis. It is preferable to select about 10 to 50 degrees, more preferably 20 to 40 degrees from the viewpoint of light uniformity and brightness.

In the case of a multi-layer structure, the same evaluation can be performed by stacking resin sheets molded to the thickness of each layer. However, for a material whose light scattering degree differs depending on the molding conditions, it is better to judge by the value when evaluated in the state of being finished in an actual cable. In this case, take out the light-scattering layer from the side-emitting cable, divide it into two, and apply a razor ray with a light diameter smaller than the diameter of the bare wire of the plastic optical fiber from the inside of the obtained semi-annular ring. It is preferable to measure the intensity of the light emitted from the back side with respect to the angle with respect to the incident optical axis, and to select the half-value width of the spectrum to be about 10 degrees to 50 degrees, more preferably 20 degrees to 40 degrees. It is preferable in terms of light uniformity and brightness.

In the plastic optical fiber, the core polymer is a resin mainly composed of methyl methacrylate. For example, it is a homopolymer of methyl methacrylate, a copolymer of methyl methacrylate and an acrylic acid ester or a methacrylic acid ester, and the like. Since the sheath polymer is required to be a plastic optical fiber having a high mechanical strength, vinylidene fluoride is preferable as the main component. For example, vinylidene fluoride having a proportion of 60% to 99% is vinylidene fluoride. Fluoride and tetrafluoroethylene copolymer, polyvinylidene fluoride, vinylidene fluoride and hexafluoropropene copolymer, vinylidene fluoride and tetrafluoroethylene and hexafluoropropene copolymer, vinylidene fluoride and trifluoroethylene and hexa Examples thereof include fluoroacetone copolymers. In particular, when it is desired to increase the light scattering loss and to enhance the light emission in a short distance, it is preferable to use a mixture of a plurality of vinylidene fluoride resins obtained by completely different production and having different compositions. By this mixing, the sheath resin becomes cloudy, and only the light scattering loss of the optical fiber is increased, and there is no light absorption loss and no adverse effect on mechanical properties.

The resin used as the light diffusing layer, when used for coating a general optical fiber, usually has carbon black added or pigment added to block ultraviolet rays, and therefore is called weather resistant. From the point of view, there is not much problem, but for side emitting cables, the light diffusion layer diffuses light, so it can not be seen through, but scattered light is a layer that shines brightly, and when installed outdoors The sun rays may enter the light diffusion layer, and the weather resistance of the light diffusion layer itself becomes a problem. In fact, it has been found that a cable that has not been light-stabilized causes a problem that the light diffusion layer becomes brittle after long-term use.

From the viewpoint of improving the weather resistance of the light-diffusing layer with respect to the resin, it was thought that an amine-based light stabilizer would be effective, but when several amine-based light stabilizers are actually used, Although the effect of maintaining the mechanical strength of the resin of the diffusion layer in the weather resistance test was observed, the plastic optical fiber itself had a problem of yellowing. In order to solve this problem, as a result of diligent studies, if a polymerized hindered amine-based compound having a number average molecular weight of 1000 or more, preferably 2000 or more is used as a light stabilizer, relatively,
It was found that the coloring of the plastic optical fiber was small and the weather resistance of the light diffusing resin could be improved. Among them, the compound having no NH bond in the molecule is particularly preferable. To give a specific example, dimethyl succinate (2-hydroxyethyl) -4-hydroxy-2,2
6,6-Tetramethylpiperidine polycondensate, average molecular weight Mn> 3000 Ciba-Gigi Tinuvin (trademark) 62
It's like 2LD.

[0014]

[Chemical 1]

Such polymer hindered amine is added to the light diffusion layer resin in an amount of usually 100 ppm to 5000 ppm, preferably 500 ppm to 3000 ppm, and the weather resistance is several times longer than that in the case where nothing is added. It starts to show stability. The adverse effect on the plastic optical fiber can be almost ignored even under severe conditions such as high temperature and high humidity.

The method of coating the diffusion layer according to the present invention is such that the bare wire of the plastic optical fiber is melt-coated with a crosshead die so that the bare wire of the plastic optical fiber is coated, and another method is There is a method of molding a hose in advance and inserting a plastic optical fiber into this, and either method is acceptable. As a method of using this cable, light is incident from one end surface or both end surfaces to emit light from the side surface, but in some cases, light is incident only from one end surface,
Light emitted from the other end can be softly illuminated by being wrapped with a diffuser which surrounds the light much larger than the thickness of the fiber like the glass bulb of a white light bulb.

[0017]

EXAMPLES The present invention will be described below with reference to examples in order to further clarify the present invention, but the scope of the present invention is not limited to these examples.

[0018]

Example 1 A molecular weight of 19.5 consisting of 99.5% MMA and 0.5% MA produced by a continuous polymerization method as a PMMA resin.
300,000 resin was directly introduced into the composite spinning die from the devolatilizing extruder, and the sheath resin was polyvinylidene fluoride and the refractive index was 1.4.
2, melting point 170 ° C, melt index (ASTM-1
238 temperature 230 ° C., weight 3.8 kg, die inner diameter 2.0955 mm) of 20 g / 10 min, vinylidene fluoride 81 mol% and tetrafluoroethylene 19 mol% melt index (ASTM-1238 temperature 2
30 ℃, Weight 3.8kg, Die inner diameter 2.0955m
The mixture of m) of 30 g / 10 min in a weight ratio of 3 to 7 was put into a sheath extruder, and the molten core polymer and the sheath polymer were introduced into a composite spinning die, and a core-sheath structure was formed at a temperature of 230 ° C. Manufactured bare plastic optical fiber. The bare wire had a diameter of 3.5 mm and a sheath thickness of 30 μm. The transmission loss of this plastic optical fiber is the incident NA = 0.
The measured value by cutback of 11m-1m at 15 is 65.
It was 200 dB / km at 0 nm. This plastic optical fiber bare wire is not colored low density polyethylene NUC-9025, 90 parts by weight made by Nippon Unicar, and thermoplastic silicone elastomer SI made by Nippon Unicar
10 parts by weight of LGRAFT-210, and a light-stabilizing white coating made of a resin in which 0.3 wt% of TINUVIN (trademark) 622LD average molecular weight Mn> 3000 of Ciba-Geigy Co., Ltd. was mixed as a light stabilizer was applied. . This layer had an inner diameter of 4.4 mm and an outer diameter of 6.0 mm.

About 1 of the light diffusion layer portion is obtained from the obtained cable.
A ring having a length of 0 mm was taken out, and this was vertically divided into halves with a razor to prepare a semi-annular sample. A He-Ne razor (NH405A manufactured by Nippon Kagaku Engineering Co., Ltd.) having a light spot diameter of about 1 mm was applied to this sample with a razor beam perpendicular to the surface of the sample from the back side, and the light emitted from the front surface was 0. Photodetector with a 0.5 mm slit on the front (81520A.OP manufactured by Hewlett Packard)
TICAL HEAD). This detector is capable of scanning on a circle with a radius of 20 mm from the center of the razor beam of the sample, and records the value obtained by reading the intensity of light at each angle with respect to the incident axis of the razor beam,
The half width was calculated. The measurement system is shown in FIG. The result of the measurement is shown in FIG. The optical power detected directly in the blank state without the sample was 300 μW. From this result, the light diffusion layer of this example had a full width at half maximum of 32 degrees.

This cable is taken for 10 m and one end surface is 10
When connected to a light source led from a 0 W halogen lamp through an optical fiber light guide through 30 cm, the brightness of 1 m, 3 m, 5 m and 9 m is 2 respectively.
It was 5, 17, 11, and 8 cd / m ² , and the cable was bent to radii of 50 mm and 80 mm at the position of 5 m to increase the light leakage, but the brightness was 60 cd / m ² and 13 cd / m.
^{It was 2} and it was found that the radius of curvature can be kept relatively small.

10 m of this cable was left in an oven at 60 ° C. and 95% relative humidity for 1000 hours to examine the change in transmission loss. The measurement is performed with a cutback of 10m and 1m at the initial stage and a cutback of 9m and 1m after the completion of the test.
It carried out by incidence NA = 0.15. As a result, the transmission loss is 200 dB / km at 650 nm in the initial and after tests.
From 30 dB / km to 30 dB / km, which is the theoretical reason due to moisture absorption.
It was stable from 50 dB / km to 152 dB / km.
Further, the light diffusing layer of this cable was heated with a sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd.) to a bath temperature of 43.
The test was conducted at 1000C for 12 hours under a water spraying condition of 12 minutes per hour. In order to measure the elongation at break of the light diffusion layer, the distance between chucks was 50 mm and the pulling speed was 100 mm / min using a tensile tester. Initial elongation at break is 400
˜470%, while the value after the test is 250% ˜4
It was 00%.

[0022]

COMPARATIVE EXAMPLE 1 The same procedure as in Example 1 was carried out except that the light stabilizer was not added to the resin of the light diffusion layer. The light diffusion layer of this cable was exposed to a sunshine weatherometer for 1000 hours, and the elongation at break before and after the exposure test was examined.
It was found that the initial value was 400 to 470%, and the value was 26 to 150%, showing a large variation and brittleness.

[0023]

Comparative Example 2 In Example 1, as a light stabilizer added to the resin of the light diffusion layer, Tinuvin 77 manufactured by Ciba-Geigy Co., Ltd.
The same was applied except that 0 and a molecular weight of 480 were added by 0.3% by weight. The cable 10m covered with this light diffusion layer is 60 ° C,
Leave it in an oven at 95% relative humidity for 1000 hours,
The change in transmission loss was investigated. The measurement was carried out with a cutback of 9 m and 1 m after the completion of the cutback test of 10 m and 1 m in the initial stage, and at an incident NA = 0.15. Initially 200 dB / km at 650 nm, 32 after testing
It was 0 dB / km. However, at 570 nm, the initial value is 1
While it was 50 dB / km, it was 200 after the test.
It increased to 0 dB / km and the plastic optical fiber became brown.

[0024]

Comparative Example 3 The plastic optical fiber of Example 1 and a bare wire having a diameter of 3.5 mm were coated with a light diffusing layer by an electric wire coating extruder. A pressure die is used as the coating die,
It was manufactured so that the bare wire and the light diffusion layer were in close contact with each other. The resin of the light diffusion layer is uncolored low density polyethylene NUC-9025 made by Nippon Unicar, 90 parts by weight, and the thermoplastic silicone elastomer SILGRAFT made by Nippon Unicar.
10 parts by weight of -210, and as a light stabilizer, Tinubin (trademark) 622LD average molecular weight Mn> of Ciba-Geigy Co.
It is a white resin having a strong light diffusivity, which is a resin in which 0.3% by weight of 3000 is mixed. The inner diameter of this light diffusion layer is 3.5.
The outer diameter was 6.0 mm and the outer diameter was 6.0 mm.

Take 10 m of this cable, and use 10
When connected to a light source led from a 0 W halogen lamp through an optical fiber light guide through 30 cm, the brightness of 1 m, 3 m, 5 m and 9 m is 2 respectively.
It was 8, 16, 10 and ⁷ cd / m ² . And 5m
When the cable was bent into a circle with a radius of 50 mm and a radius of 80 mm at the position, and the leakage light was increased, the brightness of that part was 1
It was 05 cd / m ² and 65 cd / m ² , and it was found that light greatly leaked with respect to the radius of curvature. Light leakage was much larger than that of the same test as in Example 1. (The more it bends, the more light it leaks, so the transmission loss increases.)

[0026]

Example 2 The same as Example 1 except that 0.3% by weight of Chimassorb (trademark) 994LD70 molecular weight Mn> 2500 manufactured by Ciba-Geigy Co., Ltd. was added as a light stabilizer added to the resin of the light diffusion layer. . 10 m of the cable coated with this light diffusion layer was left in an oven at 60 ° C. and 95% relative humidity for 1000 hours, and the change in transmission loss was examined. The measurement is performed with a cutback test of 10 m and 1 m in the initial stage and a cutback of 9 m and 1 m after the completion of the test, and the incident NA = 0.15.
It was carried out in. Initially 200 dB / k at 650 nm
m, and was 250 dB / km after the test. At a short wavelength of 570 nm, the initial value was 150 dB / km, whereas after the test, it was 300 dB / km, which was almost usable. Further, the light diffusion layer of this cable was subjected to a weather resistance test for 1000 hours with a sunshine weatherometer, and the initial elongation at break was 400 to 470.
%, The value after the test was 320% to 420%.

[0027]

EFFECTS OF THE INVENTION A side light emitting cable that is homogeneous, clean, bright, and emits soft light, and has excellent weather resistance.

[Brief description of drawings]

FIG. 1 is a sectional view of a plastic optical fiber structure of the present invention (in the case of a single bare wire)

FIG. 2 is a sectional view of a plastic optical fiber structure of the present invention (in the case of a plurality of bare wires)

FIG. 3 is a device for evaluating the degree of diffusion of a light diffusion layer.

FIG. 4 is a spectrum of light diffusivity of Example 1.

[Explanation of symbols]

 1, core 2, sheath 3, gap 4, light diffusion layer

Claims (3)

[Claims] 1. A light-diffusing layer comprising a hose-like material made of a material obtained by adding a polymerized hindered amine-based light stabilizer to an opaque resin composed of a polyolefin resin and a thermoplastic silicone elastomer. A side emitting cable in which a bare optical plastic fiber whose core is made of a resin mainly containing methyl methacrylate and whose sheath is made of a resin mainly containing vinylidene fluoride is arranged. 2. The side light emitting cable according to claim 1, wherein the light stabilizer is a hindered amine-based polymer having a molecular weight of 2000 or more and does not have an NH structure in its molecular structure. 3. The bare plastic optical fiber disposed in the light diffusion layer has a diameter of 2 mm to 5 mm,
Also, a side surface emitting cable, in which only one wire is arranged and a gap of 100 μm or more is present in 20% or more of the entire circumference of the bare wire between the light diffusing layer directly covering the bare wire.