JPH0345908A - Plastic optical fiber having heat resistance - Google Patents

Abstract

PURPOSE:To obtain the plastic optical fiber which has excellent heat resistance by consisting a core material of two kinds of polycarbonate copolymers having specific repeating units. CONSTITUTION:The core material consists of a polycarbonate copolymers having at least the repeating unit expressed by formula I and the repeating unit expressed by formula II. In the formulas I and II, X1 to X4 denote a hydrogen atom, >= 1C alkyl group (more preferably 1 to 4C alkyl group), chlorine atom, bromine atom or fluorine atom. There is no particular limitation for the ratio of the repeating unit expressed by the formula I and the repeating unit expressed by the formula II and can be adequately determined according to applications and required characteristics. The plastic optical fiber which has an excellent heat resistance and is adequate for use in sections, such as in the engine room of automobiles, where the temp. rises to a high temp., is obtd. in this way.

Description

[Detailed description of the invention] (Industrial application field).

The present invention relates to a plastic optical fiber having high heat resistance.

(Prior Art) Conventionally, fibers for transmitting light have been made of quartz glass or plastic. Silica glass optical fibers have low loss and are currently widely used for long-distance transmission. Although the transmission loss of plastic optical fibers is greater than that of quartz glass fibers, they are flexible, lightweight, and easy to process, so they are used in electronic equipment and the like for short-distance transmission.

Most of the plastic optical fibers currently in practical use have a core material made of highly transparent poly(methyl methacrylate), but poly(methyl methacrylate)
Since the glass transition point of plastic optical fibers is about 100° C., these plastic optical fibers cannot be used for transmitting control signals of automobiles in the engine room of automobiles where the temperature is high (for example, 150° C. or higher).

Therefore, various attempts have been made to improve the heat resistance of plastic optical fibers. For example, in order to improve the heat resistance of poly(methyl methacrylate), there is a method of copolymerizing methyl methacrylate and N-arylmaleimide (Japanese Patent Publication No. 43-9753), and a method of imidizing a part of poly(methyl methacrylate). Attempts have been made such as a method of copolymerizing methyl methacrylate and α-methylstyrene (Japanese Patent Application Laid-open Nos. 60-184212 and 60-185905). In addition, in recent years, polycarbonate has come to be used as a core material other than poly(methyl methacrylate) (Japanese Patent Application Laid-open Nos. 57-46204 and 61-66).
No. 04).

(Problem to be solved by the invention) However, even the conventionally used plastic optical fiber made of polycarbonate has a heat resistance temperature of 125°C.
It was not able to withstand the high temperatures found in the engine room of a car.

An object of the present invention is to provide a plastic optical fiber with excellent heat resistance.

(Means for Solving the Problems) The above object of the present invention is that the core material has at least one type of general formula (wherein x, , x, , Xs and X4 are hydrogen atoms, and the number of carbon atoms is 1 or more represents an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms), a chlorine atom, a bromine atom, or a fluorine atom, which may be the same or different from each other; and a repeating unit represented by the general formula (in the formula, X+, X2, Xs and x4 are hydrogen atoms,
An alkyl group having 1 or more carbon atoms (preferably 1 to 4 carbon atoms)
(alkyl group), chlorine atom, bromine atom, or fluorine atom, and may be the same or different from each other. ) This was achieved using a plastic optical fiber characterized by being made of a polycarbonate copolymer having repeating units represented by:

In the present invention, the ratio of the repeating unit represented by the above general formula (I) to the repeating unit represented by the general formula (II) is not particularly limited and can be determined as appropriate depending on the use, required characteristics, etc., but is preferably The ratio is 1:9 to 7:3.

The polycarbonate used for the core material of the plastic optical fiber of the present invention has general formula (I) as the third structural unit.
, (II) but having different structures, the following aromatic polycarbonate components (1) to (5), aromatic polyesters, polysiloxanes, etc. may be copolymerized.

Specific examples of copolymer components Shimon 3 CH.

In the above formula, Y1 to Y4 are hydrogen atoms, hydrocarbon groups (for example,
methyl group, ethyl group, isopropyl group, etc.), or a halogen atom (C, Br, etc.).

The sheath material used in the plastic optical fiber of the present invention is a fluororesin (e.g., tetrafluoroethylene,
homopolymers or copolymers of vinylidene fluoride, propylene hexafluoride, etc.), polymethylpentene polymers, imidized or dehydrated methacrylic acid polymers,
An acrylic compound having a long alkyl chain or a polycarbonate having a relatively low refractive index having a repeating unit can be used.

When spinning the plastic optical fiber of the present invention, a higher temperature than before is required because the resin has a high glass transition point. In other words, in the case of poly(methyl methacrylate) resin, it is 240
The temperature was about 300°C, but it is necessary to raise the temperature to about 300°C or more.

Other points can be spun according to conventional methods.

(Example) Next, the present invention will be explained in more detail based on examples.

Examples As shown in Experiment Nos. 1 to 25 in Table 1 below, one type of copolymerization component among bisphenol AF, tetrabromobisphenol AF, tetrachlorobisphenol AF, tetrafluorobisphenol AF, and tetramethylbisphenol AF, Bisphenol S, Tetrabromobisphenol S, Tetrachlorobisphenol S1
A polycarbonate was synthesized by the phosgene method using tetrafluorobisphenol S1 and one type of tetramethylbisphenol S in a weight ratio of 50:50. The heat distortion temperature of the obtained polycarbonate is 180-2
The temperature was in the range of 50°C, and the refractive index was 1.56 to 1.62. The average molecular weight is approximately 18,000 to 20,000.
Met. This polycarbonate was fed under oxygen-free conditions to a double extruder with a melting section temperature of 300° C. or higher.

On the other hand, FEP (polyfluorinated ethylene propylene), which is a cladding material, was also supplied to the double extruder. The core material and cladding material fed into these double extruders were extruded through a spinneret. The extruded fiber was cooled and then wound. The core diameter of the optical fiber was approximately 800 μm, and the cladding thickness was 1100 μm. Loss measurement is 770nm LE
Performed with 12m/2m cutback method using D light source.lk
It was calculated by converting it into a loss value in m. In order to compare the heat resistance, 10 m of the fiber was exposed to 150° C. for 5 days, and then the loss value was measured again with a 10 m/2 m cutback. The results are also shown in Table 1.

Comparative example Bisphenol A and bisphenol A as copolymerization components
A polycarbonate copolymer was synthesized by the phosgene method in the same manner as in the example except that F was used at a weight ratio of 50:50. The heat distortion temperature of the obtained polycarbonate was 171°C
The refractive index was 1.57. The average molecular weight is approximately 2
It was 0,000. Using this polycarbonate, an optical fiber was manufactured in exactly the same manner as in the example, and the same tests as in the example were conducted. The results are shown in Table 1 for Experiment No. 26.
It is also shown as

Next, as Experiment No. 27, a polycarbonate made from bisphenol A, Panlite L-1250 (trade name, manufactured by Kijin Kasei Co., Ltd., average molecular weight: 20.000), was selected as the core material. The refractive index was about 1.59. This polycarbonate was fed under oxygen-free conditions to a double extruder with a melting point of 280°C. On the other hand, poly(4-methylpentene-1) was used as a cladding material and fed to a double extruder. After that, the same treatment as in the example was performed. 7
Fiber loss value at 70nm is 1200dB/k
However, after heat treatment at 150 °C for 5 days, the loss value was observed to increase by about 400 dB/km. The results are shown in Table 1.

As is clear from the results in Table 1, the samples of the present invention have better heat resistance than the comparative examples, as shown by the loss value after heat treatment at 150° C. for 5 days.

(Effects of the Invention) An optical fiber using the specific polycarbonate copolymer of the present invention as a core material has extremely excellent heat resistance and is suitable for use in areas that reach high temperatures, such as the engine room of an automobile.

Claims (1)

[Claims] At least one core material has a general formula ▲ Numerical formula, chemical formula, table, etc. ▼...(I) (In the formula, X_1, X_2, X_3 and The above alkyl groups, chlorine atoms, bromine atoms, or fluorine atoms may be the same or different. In the formula, X_1, X_2, X_3 and X_4 represent a hydrogen atom, an alkyl group having 1 or more carbon atoms, a chlorine atom, a bromine atom or a fluorine atom, and may be the same or different from each other. A plastic optical fiber comprising a polycarbonate copolymer having