JPH0713031A - Plastic optical fiber - Google Patents

Abstract

PURPOSE:To provide the plastic optical fiber having high heat resistance and the excellent reproducibility of exit light by forming a core layer of a silicone resin contg. coloring agents. CONSTITUTION:The core layer of the plastic optical fiber consisting of the core layer and clad layer consists of the silicone resin contg. the coloring agent, of which the max. absorption wavelength in a visible light region exists in a 550 to 700nm range. The coloring agents to be added to the silicone resin of the core layer are required to be dissolved in the silicone resin of the core material. Such coloring agents are preferably oil-soluble dyes of an anthraquinone system, phthalocyanine system, triphenyl methane system and are more preferably the dyes of a phthalocyanine system if heat resistance is taken into consideration. The silicone resins may be properly selected and adopted from commercially marketed coloring agents. The effect is insufficient if the amt. of the coloring agents is too little. Transmission loss increases drastically and exist light colors blue if the amt. thereof is to much.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic optical fiber preferably used as an illumination or a fiberscope.

[0002]

2. Description of the Related Art Although a plastic optical fiber has a large transmission loss, it has a large aperture coefficient, is flexible, can be made large in diameter, and has good terminal processability. Therefore, it is expected as an optical light guide. There is. Conventionally, a plastic optical fiber mainly used as an optical light guide has a core layer formed of polymethylmethacrylate. However, this plastic optical fiber having a core layer of polymethylmethacrylate has poor heat resistance, and its heat resistance is about 85.degree. Therefore, in order to improve heat resistance, a plastic optical fiber whose core layer is made of polycarbonate has been developed in recent years.When light enters a plastic optical fiber whose core layer is made of polycarbonate, the emitted light becomes yellowish and white light is emitted. However, there was a drawback that the light could not be transmitted as it was. In order to improve this, it has been considered to add a blue dye to the polycarbonate of the core layer to whiten it, but it has to be molded at a high temperature, and an increase in loss is observed due to decomposition of the dye in the core layer. It has been difficult to produce a product that can withstand use.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plastic optical fiber having high heat resistance and excellent reproducibility of emitted light.

[0004]

The inventors of the present invention have conducted various studies in order to overcome the drawbacks of the conventional plastic optical fiber, and as a result, have formed a silicone resin as a core layer and forming a clad layer on the core layer. It was found that by adding a predetermined amount of blue dye to the silicone resin composition of the core layer in the production of the plastic optical fiber, the optical properties of the obtained plastic optical fiber are remarkably improved. The present invention has been completed based on the findings. That is, the present invention is a plastic optical fiber comprising a core layer and a clad layer, wherein the core layer is made of a silicone resin containing a colorant having a maximum absorption wavelength in the visible light range of 550 nm to 700 nm. A plastic optical fiber is provided.

The colorant added to the core layer silicone resin of the present invention has a maximum absorption wavelength in the visible light region of 550 n.
The colorant needs to be in the range of m to 700 nm and needs to be dissolved in the core material silicone resin. As such a colorant, oil-soluble dyes such as anthraquinone type, phthalocyanine type and triphenylmethane type are preferable, but phthalocyanine type dyes are preferable in consideration of heat resistance. This colorant can be appropriately selected and used from the commercially available products. The amount of the blue colorant varies depending on the type of the core material silicone resin and the colorant, but is preferably 0.
001 ppm to 100 ppm, more preferably 0.05
ppm to 10 ppm. If the amount of the colorant is too small, the effect is insufficient, and if it is too large, the transmission loss remarkably increases or the emitted light is colored blue.

The core material silicone resin used in the plastic optical fiber is not particularly limited. For example, (1) an organopolysiloxane containing at least two alkenyl groups in one molecule (2) the above (1) Organohydrogenpolysiloxane having at least 2 hydrogen atoms in one molecule in an amount sufficient to give 0.5 to 5 hydrogen atoms bonded to silicon atoms per alkenyl group in component (3) (3) Platinum Compound (4) It is a composition of 100 to 5000 cps, which is usually composed of a coloring agent. A composition that cures is used. Examples of the organopolysiloxane containing at least two alkenyl groups in one molecule of the above (1) include those having the following structures.

[0007]

[Chemical 1]

In the component (1), the organic group other than the alkenyl group directly bonded to the silicon atom and the oxygen atom is not particularly limited, but is preferably a substituted or unsubstituted monovalent hydrocarbon group, It is preferably composed of a methyl group and a phenyl group. Further, it has at least two hydrogen atoms in one molecule in an amount sufficient to give 0.5 to 5 hydrogen atoms bonded to silicon atoms per one alkenyl group in the component (1) of the above (2). Examples of the organohydrogenpolysiloxane include those having the following structures. The organohydrogenpolysiloxane as the component (2) is a cross-linking agent for curing the composition by forming a cross-linking reaction by the addition reaction with the alkenyl group as the component (1), and as described above, one molecule has one molecule. It has two or more hydrogen atoms directly bonded to silicon atoms.

[0009]

[Chemical 2]

In the component (2), the organic group other than the hydrogen atom and oxygen atom directly bonded to the silicon atom is not particularly limited, but is a substituted or unsubstituted monovalent group containing no aliphatic unsaturated group. It is preferably a hydrocarbon group, and more preferably a methyl group and a phenyl group. The organohydrogenpolysiloxane may have any of a chain structure, a branched chain structure and a network structure. This may be a single substance or a mixture of two or more types. Further, in order to increase the transparency among the constituents of the silicone resin composition and to suppress yellowing of the light emitted from the plastic optical fiber as much as possible, the amount of the platinum catalyst is preferably 5 ppm or less with respect to the entire silicone resin. It is necessary to suppress the amount to preferably 2 ppm or less. Further, it is preferable that the core material silicone resin is sufficiently subjected to purification treatment such as filter treatment. In the past, it was impossible to whiten the emitted light only by suppressing the amount of platinum catalyst, but whitening is possible by adding a predetermined amount of blue colorant to the core material as in the present invention. Became. As the clad layer resin, a resin having a smaller refractive index than the core portion and further high heat resistance is used. As such a clad layer resin, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer , Polytetrafluoroethylene, polymethylpentene, Teflon AF,
Cytop etc. are mentioned.

Unlike the case of a thermoplastic resin such as polycarbonate, the plastic optical fiber of the present invention has a very low molding temperature of the fiber core layer of about 150 ° C. or less, and deterioration of the contained blue colorant (dye). It hardly happens. Therefore, yellowing of the core material and deterioration of transmission efficiency due to deterioration of the dye hardly occur, and when white light is incident on such a plastic optical fiber, white light can be emitted with high efficiency without yellowing. It has become possible. Further, in the case of such a curable silicone resin, the colorant is easily mixed and the dispersibility is excellent, so that the emission color characteristics can be effectively controlled by the blue colorant. In the present invention, the colorant can be contained in the silicone resin composition by dispersing it in the silicone resin composition and curing it after defoaming, and the method is simple, and the possibility of contamination of impurities is extremely small. Can be suppressed. Next, the method for producing the plastic optical fiber of the present invention will be specifically described. After the tube is made of the clad material, the inside of the tube is thoroughly washed and dried. Next, a liquid silicone resin is mixed, and a blue dye is added thereto and mixed well. After mixing, degas this thoroughly. This is introduced into the above-mentioned tube, and after introduction, it is cured by heat, electron beam, radiation or the like to obtain a plastic optical fiber having a core-clad layer.
In the plastic optical fiber of the present invention, a protective layer is provided on the outside of the clad layer for the purpose of blocking the light from the outside, blocking the water to the core, and improving the fiber strength. It may be provided. The protective layer resin is not particularly limited, but examples thereof include polyarylate, polycarbonate, polysulfone, ethylene-tetrafluoroethylene copolymer, and hexafluoropropylene-tetrafluoroethylene copolymer.

[0012]

The present invention will be described in more detail based on the following examples. The measurement was performed by the following method. The silicone resin used is as follows. -Transmission loss: A 660 nm LED was used as a light source and measured by the 5 m-1 m cutback method. -Emitting light characteristic at each wavelength White light was made incident on a plastic optical fiber cut to a length of 2 m and subjected to terminal treatment through a monochromator, and the emitted light was measured by a photomarmeter. The measurement was performed continuously between 890 nm and 350 nm at a speed of 60 nm / min. A tungsten lamp was used as the white light source. Two-component mixed thermosetting silicone resin A A composition containing the following components 1), 2) and 3). 1) Linear methylphenylpolysiloxane 98.1 parts by weight of which both ends of the molecular chain are blocked with vinyldimethylsilyl groups 2) Methylhydrogenpolysiloxane having 1.21 mol / 100 g of hydrogen atoms bonded to silicon atoms 1.9 parts by weight 3) Octyl alcohol chloroplatinate modified solution 0.005 parts by weight (platinum content 2% by weight)

Example 1 To 100 g of a two-component mixed thermosetting silicone resin A was added 10 mg of a blue dye Oil Color Blue BOS (Orient Chemical Co., Ltd.) diluted to 0.1% with a toluene solution.
After mixing well, defoaming was performed to prepare a silicone resin core material. An FEP tube with an inner diameter of 3φ and an outer diameter of 4φ is cut into 8 m, and the inside is thoroughly washed with Fluorinert FC72, dried while flowing nitrogen gas into this tube, and further 120 ° C.
And dried for 6 hours. The above silicone resin was pressed into this tube at a pressure of 5 kgf / cm ² , introduced for 8 m, and the end was closed and sealed. Next, from this end, linear velocity 0.5m / min, 3
Primary curing was performed in a furnace at 50 ° C., and the core layer was completely cured by heating at 150 ° C. for 6 hours to obtain a plastic optical fiber. The transmission loss at 660 nm of this plastic optical fiber was 1500 dB / km. When the plastic optical fiber 2m was cut and white light was made incident, the emitted light was almost white light.
Moreover, when the emitted light characteristics at each wavelength are measured,
As shown, the output light characteristics were almost flat in the visible light region.

Example 2 5 mg of a blue dye Savinyl Blue RS (manufactured by Orient Chemical Industry Co., Ltd.) diluted to 0.1% with toluene was added to 100 g of a two-liquid type thermosetting silicone resin A, and well mixed and defoamed. Then, a core material silicone resin was prepared, and thereafter, a plastic optical fiber was prepared in the same manner as in Example 1. The transmission loss at 660 nm of this plastic optical fiber was 1400 dB / km. When this plastic optical fiber 2m was cut and white light was incident,
The emitted light was almost white light.

Comparative Example 1 100 g of the two-component mixed thermosetting silicone resin A was thoroughly mixed and then defoamed to prepare a core silicone resin. Thereafter, a plastic optical fiber was prepared in the same manner as in Example 1. The transmission loss at 660 nm of this plastic optical fiber was 1200 dB / km. When the plastic optical fiber 2m was cut and white light was made incident, the emitted light was yellowish. Further, when the emitted light characteristics at each wavelength were measured, it was confirmed that the absorption intensity was shorter in the short wavelength region in the visible light region as shown in FIG.

[0016]

The plastic optical fiber of the present invention contains a blue colorant in the core silicone resin, has excellent heat resistance, and has uniform emission light characteristics in the visible light region.
It is preferably used for making a plastic light guide. Such an optical light guide having excellent heat resistance can be applied to a high output light source, and its effect is great as a plastic optical fiber used for medical devices, automobiles, and the like.

[Brief description of drawings]

FIG. 1 is a graph showing emission light characteristics of a plastic optical fiber obtained in Example 1 in comparison with those in Comparative Example 1.

Claims (2)

[Claims] 1. A plastic optical fiber comprising a core layer and a clad layer, wherein the core layer is made of a silicone resin containing a colorant having a maximum absorption wavelength in the visible light range of 550 nm to 700 nm. Plastic optical fiber. 2. The amount of colorant in the silicone resin is 0.0
The plastic optical fiber according to claim 1, wherein the content is 01 ppm to 100 ppm.