JPH0361911A - Heat resistant plastic optical fiber - Google Patents

Abstract

PURPOSE:To obtain the optical fiber having excellent heat resistance by using a specific polycarbonate copolymer as a core material. CONSTITUTION:The core material is so formed as to consist of at least one kind of the polycarbonate copolymers having the repeating unit expressed by formula I and the repeating unit expressed by formula II. In the formula II, X1 to X4 denote a hydrogen atom, halogen atom (more preferably chlorine, fluorine, bromine) or alkyl group (more preferably 1 to 4C alkyl group), which may be the same as or different from each other. The part of the formula I in this polycarbonate copolymer improves transparency and the part of the formula II improves the heat resistance. The copolymn. ratio of both is preferably 20 to 90wt.% for the part of the formula I and 10 to 80wt.% for the part of the formula II, more preferably 25 to 85wt.% for the part of the formula I and 20 to 75wt.% for the part of the formula II. The plastic optical fiber having excellent heat resistance is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) 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 higher than that of quartz glass fibers, they are flexible, lightweight, and easy to process, so they are used in electronic equipment for short-distance transmission and are not currently in practical use. The core material of most of the plastic optical fibers that are used in the
Since the glass transition point of II (methyl methacrylate) is about 100°C, these plastic optical fibers reach high temperatures (for example, 150°C). Above) It cannot be used for transmitting control signals of a vehicle in the engine room of a vehicle.

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 problems) The above object of the present invention is that the core material is A repeating unit represented by formula (In the formula, X.

X3 and X4 are hydrogen atoms, halogen atoms (preferably chlorine, fluorine, bromine)
or an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms), which may be the same or different from each other. This was achieved by a plastic optical fiber characterized in that it consists of at least one polycarbonate copolymer having repeating units represented by:

In the polycarbonate copolymer used in the core material of the present invention, the part represented by formula (I) improves transparency, and the part represented by formula (n) improves heat resistance.

The copolymerization ratio of both is preferably such that the moiety of formula CI) is 20
~90% by weight, 10-80% by weight of the moiety of formula (n), more preferably 25-80% by weight of the moiety of formula (I)
, the moiety of formula (II) is 20 to 75% by weight. Formula (I
) If the proportion of the portion is too small, the transmission loss will decrease, and if the proportion is too large, the heat resistance will decrease.

Used in the core material of the plastic optical fiber of the present invention
#+1 +! &+−1,1,+f (T
1T)L+ (In addition to those represented by TTl, it may be copolymerized with the following aromatic polycarbonate components (1) to (5), aromatic polyester, polysiloxane, etc.

Specific examples of copolymerizable components In the above formula, Y and -Y4 represent a hydrogen atom, a hydrocarbon group (eg, a phosphorus 1-methyl group, an ethyl group, an isopropyl group, etc.), or a halogen atom (C°C, Br, etc.).

When the polycarbonate used in the core material of the present invention contains a copolymer component other than general formula (I) or (II) as described above, the content thereof is preferably 10% by weight or less.

The component of formula (I) of the polycarbonate used as the core material of the plastic optical fiber of the present invention has a cyclic group between the benzene rings, so it has a large amorphous property and is different from conventional bisphenol A. It has higher transparency than the resulting polycarbonate.

Furthermore, the polycarbonate of the present invention has a repeating unit represented by formula (n) and has higher heat resistance than polycarbonate obtained from conventional bisphenol A.

The sheath material used in the plastic optical fiber of the present invention may be a fluororesin (for example, a homopolymer or copolymer of tetrafluoroethylene, vinylidene fluoride, propylene hexafluoride, etc.), or a polymethylpentene polymer. , imidized or dehydrated methacrylic acid polymers, acrylic compounds with long alkyl chains, or polycarbonates with a relatively low refractive index such as those with repeating units, and are not particularly limited as long as they have heat resistance of 150°C or higher. .

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.

Example 1 Using bisphenol Z and bisphenol AF as starting materials (mixed molar ratio 1:1), polycarbonate (components of formula (I) and
A copolymer with a hydrogen atom component) was synthesized. The heat distortion temperature of the obtained polycarbonate was 175°C, and the refractive index was 1.54. Also, the average molecular weight is 28.000
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 8001 Lm, and the cladding thickness was 1100 tL. The fiber loss value at 770 nm is 1200 dB/km and 150
Almost no change was observed in the loss value even after heat treatment for 1 day at °C.

Example 2 Using bisphenol Z and tetrachlorobisphenol AF as starting materials (mixing molar ratio 1:1), polycarbonate (a component of formula (I) and a component of formula (II) in which X1 to copolymer) was synthesized. The heat distortion temperature of the obtained polycarbonate was 190°C, and the refractive index was 1.59. Also, the average molecular weight is 3
It was 3.000. 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, 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 tLm, and the cladding thickness was 100 μm.

The fiber loss value at 770nm is 1200dB
/km, and almost no change was observed in the loss value even after heat treatment at 150°C for 1 day.

Example 3 A polycarbonate copolymer was synthesized by the phosgene method using bisphenol Z and bisphenol AF (fi combined molar ratio 8:2) as starting materials. The heat distortion temperature of the obtained polycarbonate was 175°C, and the refractive index was 1.53. Moreover, the average molecular weight was 28.000. When this polycarbonate is heated in an oxygen-free state, the temperature of the melted part is 300℃.
The above double extruder was fed. On the other hand, poly(4-methylpentene-1) was used as a cladding material and fed to a double extruder. The rest of the process was carried out in the same manner as in Example 1. 770
The loss value of the fiber at nm is 1100 dB/km, and even after heat treatment at 150°C for 1 day, the loss value is 300 dB.
/km.

Example 4 Bisphenol Z and bisphenol AF (mixing molar ratio 2
: Polycarbonate was synthesized by the phosgene method using 8) as a starting material. The heat distortion temperature of the obtained polycarbonate was 180°C, and the refractive index was 1.52. Moreover, the average molecular weight was 28.000. This polycarbonate was fed under oxygen-free conditions to a double extruder where the temperature of the melting section was 300°C or higher. On the other hand, poly(4-
Methylpentene-1) was used to feed the double extruder.

After that, the same treatment as in Example 1 was performed. The fiber loss value at 770 nm is 1500 dB/km and 15
Even after heat treatment at 0°C for 1 day, almost no change was observed in the loss value.

Comparative Example 1 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 approximately 1.59. This polycarbonate was fed under oxygen-free conditions to a double extruder with a melting section temperature of 280° C. or higher.

On the other hand, poly(4-methylpentene-1) is used as a cladding material.
was used to feed the double extruder. After that, the same treatment as in Example 1 was performed. The loss value of the fiber at 770 nm is 1200 dB/km, and after heat treatment for 150'' CI days, the loss value is 1 ooo.

An increase of more than dB/km was observed.

Comparative Example 2 A polycarbonate (a polymer consisting only of the components of formula (I)) was synthesized using bisphenol Z by the phosgene method. The heat distortion temperature of the obtained polycarbonate was I70°C, and the refractive index was 1.59. Also, the average molecular weight is 28,
It was 000. This polycarbonate was fed under oxygen-free conditions to a double extruder where the temperature of the melting section was 300°C or higher.

On the other hand, poly(4-methylpentene-1) is used as a cladding material.
was used to feed the double extruder. After that, the same treatment as in Example 1 was performed. The loss value of the fiber at 770 nm was ILOO dB/km, and after heat treatment at 150° C. for 1 day, the loss value increased by more than 1000 dB/km.

Comparative Example 3 Polycarbonate (formula (II) in which X, ~X4 are hydrogen atoms) by the phosgene method using bisphenol AF as a starting material
A polymer consisting only of the following components was synthesized. The heat distortion temperature of the obtained polycarbonate was 183°C, and the refractive index was 1.50.

Moreover, the average molecular weight was about 25,000. When this polycarbonate is heated in an oxygen-free state, the temperature of the melted part is 300℃.
It was fed into a double extruder above ℃.

On the other hand, poly(4-methylpentene-1) is used as a cladding material.
was used to feed the double extruder. After that, the same treatment as in Example 1 was performed. The fiber loss value at 770 nm was 1700 dB/km.

Comparative Example 4 A polycarbonate (a polymer consisting only of the component of formula (II) in which X and -X4 are chlorine atoms) was synthesized by the phosgene method using tetrachlorobisphenol AF as a starting material.

The heat distortion temperature of the obtained polycarbonate was 205°C, and the refractive index was 1.59. Also, the average molecular weight is 32
,000. 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, poly(4-methylpentene-1) was used as a cladding material and fed to a double extruder. The rest is Example 1
The same process was performed. The fiber loss value at 770 nm was 1700 dB/km.

(Effects of the Invention) By using a polycarbonate copolymer as a core material in the present invention, it is possible to obtain a plastic optical fiber that has a high numerical aperture and can withstand high temperatures.

Claims (1)

[Scope of Claims] The core material is a repeating unit represented by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (I) and the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (II) (In the formula, X_1, X_2, X_3 and X_4 represent a hydrogen atom, a halogen atom or an alkyl group, and may be the same or different from each other. A plastic optical fiber characterized by: