JPH0572424A - Plastical optical fiber - Google Patents

Abstract

PURPOSE:To extremely enhance heat resistance and to decrease transmission losses by having specific polycarbonate controlled in mol.wt. between 20000 to 100000 as the core of the fiber, thereby constituting the above-mentioned optical fiber. CONSTITUTION:The core is formed of the modified polycarbonate copolymer having the main chain expressed by formula I and having 20000 to 100000 average mol.wt. In the formula I, R1 and R2 respectively denote a hydrogen atom, lower alkyl group or trifluoromethyl group. Further, R1, R2 may together form a ring; n denotes a positive number. The mechanical strength of the modified polycarbonate copolymer when made into the fiber is insufficient if the average mol.wt. is below 20000. The spinning to the fiber is extremely difficult if the average mol.wt. exceeds 100000.

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 having high heat resistance.

[0002]

2. Description of the Related Art Conventionally, an optical fiber is made of inorganic glass and has been widely used for signal transmission for long distance transmission. In recent years, plastic optical fibers have been inferior in transmission loss to conventional inorganic glass optical fibers, but have been widely used for electronic devices because they are resistant to bending, are not easily broken, are lightweight, and are easy to handle. In many of the plastic optical fibers currently in practical use, the core material is composed of polymethylmethacrylate having good light transmittance, but the heat resistance temperature of polymethylmethacrylate is about 100 ° C. It cannot be used for sensors in microwave ovens or for transmitting control signals in the engine room of automobiles.

Therefore, various attempts have been made to improve the heat resistant temperature of plastic optical fibers. For example, a method of copolymerizing methyl methacrylate and maleic anhydride,
A method of copolymerizing methyl methacrylate and N-arylmaleimide, a method of imidizing a part of polymethylmethacrylate (JP-A-60-184212, 60-1).
No. 8590) has been proposed.

Further, studies have been made on the use of polycarbonate instead of polymethylmethacrylate (JP-A-57-46204 and 61-6604). Further, among these polycarbonates, studies have been made on a plastic optical fiber having a core material of a polycarbonate made of bisphenol AF or bisphenol Z, which has a higher glass transition point than that of a usual bisphenol A-based polycarbonate (JP-A-64-19308). Issue 6
4-28602).

[0005]

However, the method of modifying polymethylmethacrylate has problems such as insufficient heat resistance and extremely low productivity. Also, the heat resistance of plastic optical fibers using polycarbonate made of bisphenol A as a core material is 12
The temperature was about 5 ° C., which was not able to withstand the high temperatures found in the engine room of automobiles.

Further, in a plastic optical fiber using a polycarbonate made of bisphenol AF or bisphenol Z as a raw material instead of bisphenol A, the glass transition temperature is high but the decomposition temperature is low, and the raw material is expensive. There were difficulties. Therefore, there is a demand for the development of a plastic optical fiber that can withstand high temperatures and that overcomes these problems.

[0007]

The object of the present invention is to provide a core material,
formula

[Chemical 2] (Respectively R ₁ and R ₂ have the formula hydrogen atom, a lower alkyl group (preferably an alkyl group having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, butyl, etc.) or a trifluoromethyl group. Further R ₁ , R ₂ together may form a ring, n is a positive number, and has an average molecular weight of 20000 to 10000.
Achieved by a plastic optical fiber characterized by being formed of a modified polycarbonate copolymer which is 0.

The polycarbonate used as the core material in the plastic optical fiber of the present invention has the structural unit of the above formula (I), and is mechanically deformed at a high temperature as compared with the polycarbonate having other structural units. And the tendency for transmission loss to increase is small. The polycarbonate used as the core material of the plastic optical fiber of the present invention can be produced, for example, according to the following formula (A).

[0009]

[Chemical 3]

In the above reaction, the biphenol bischloroformate ester (1) is dissolved in an organic solvent such as methylene chloride or a mixed solvent of an organic solvent and water to prepare a bisphenol represented by the formula (2) and an alkali hydroxide such as caustic soda. The aqueous solution is added dropwise at 0 to 50 ° C or added in several batches, and then usually 2 hours to 1 until the desired molecular weight is reached.
It is performed by stirring for 0 hours.

The molar ratio of the reaction is 0.9 to 1.1 mol, preferably equimolar, of the bisphenol represented by the formula (2) to 1 mol of the biphenol bischloroformate ester of the formula (1), and the alkali hydroxide is 1 mol. 0.8 to 2.2 mol, preferably around 2 mol, and 0 to 2.
It is also possible to add 0 mol.

When the desired molecular weight is reached, the stirring can be stopped and a conventional post-treatment can be carried out to obtain the copolymer. The polycarbonate of the present invention has the following formula (B)
Can also be manufactured according to.

[0013]

[Chemical 4]

This reaction and polymerization can be carried out in the same manner as in the above reaction formula (A). The bischloroformate ester represented by the formula (1) or (3) is represented by the formula (4).
Alternatively, it can be obtained by phosgenating the compound represented by (2).

The modified polycarbonate polymer of the present invention thus obtained has an average molecular weight of 20,000 to 100.
It is necessary to be 000, and if it is less than 20,000, the mechanical strength when made into a fiber is insufficient, and
If it exceeds 0000, the fiber spinning process becomes extremely difficult.

As the sheath material used in the plastic optical fiber of the present invention, a fluorine resin (for example, homopolymer or copolymer of tetrafluoroethylene, vinylidene fluoride, propylene hexafluoride, etc., fluorinated acrylic resin,
A fluororesin having an aliphatic or aromatic ring in its main chain), polymethylpentene, an imidized or dehydrated methacrylic acid polymer, a polymer of a long-chain acrylic compound, or the like may be used as long as it has a heat resistance of 150 ° C. or higher. ..

A protective layer may be provided outside the sheath layer.
Examples of the protective layer include engineering plastics such as polycarbonate, polyarylate, polysulfone, polyamide, and polyethersulfone.

When the plastic optical fiber of the present invention is spun, it can be obtained by composite spinning according to a conventional method.
The spinning head temperature varies depending on the structural unit (I), but is 28
Spinning is performed at about 0 to 330 ° C.

[0019]

EXAMPLES The present invention will be described in more detail based on examples.

Example 1 Biphenol bischloroformate ester was produced according to the following formula.

[0021]

[Chemical 5]

400 ml of tetrahydrofuran was added to a 1-liter flask equipped with a stirrer, a thermometer, and a gas introduction tube, and 140 g of phosgene was blown at -10 ° C to -5 ° C to dissolve it. Then, while stirring this, 74.4 g of biphenol was added and dissolved, and then 96.8 g of N, N-dimethylaniline was added dropwise at -5 to 0 ° C for 1 hour. After dropping, the mixture was stirred at the same temperature for 30 minutes and then gradually heated to 20 to 20.
After reacting at 25 ° C. for about 3 hours under stirring, degassing was performed. The reaction solution was poured into ice water, and the precipitated crystals were collected by filtration, washed with water, dried, and recrystallized with acetone. Yield 73.0 g (59% yield), m.p. p. = 130-1
31 ° C

Then, a bisphenol A-biphenol type polycarbonate was synthesized according to the following formula.

[0024]

[Chemical 6]

To a 1 liter flask equipped with a stirrer and a thermometer, 625 ml of methylene chloride was added, and while stirring,
31.1 g of biphenol bischloroformate was added and dissolved. Further, 125 ml of ion-exchanged water was added thereto, and then a solution in which 22.8 g of bisphenol A was dissolved in 228.6 g of a 3.5% sodium hydroxide aqueous solution was added dropwise at 20 to 25 ° C. for 1 hour while sufficiently stirring. After the dropping, stirring was continued at the same temperature, and after 8 hours, the molecular weight was 30,000 (GPC,
(Converted to polystyrene), the stirring was stopped and the mixture was allowed to stand.

The aqueous layer was separated, and the methylene chloride layer was washed with ion-exchanged water, 1% hydrochloric acid and ion-exchanged water, azeotropically dehydrated and then filtered with a 0.1 μm filter. Then, the filtrate was poured into 1.2 liters of methanol, and the precipitated crystals were filtered and dried. Yield 39.5 g (yield 85%) The obtained polycarbonate was determined by ¹ H-NMR to be of formula (I)
It was confirmed to be an alternating copolymer having the structure shown in. δ (ppm): 1.70 (s, 6H), 7.20 (d,
4H) 7.27 (d, 4H), 7.35 (d, 4H) 7.59 (d, 4H)

This polycarbonate had a melting point at 252 ° C. If this is raised to a temperature above the melting point and rapidly cooled, amorphization occurs and the melting point does not appear, and the glass transition point is 16
Appeared at 5 ° C. This polycarbonate was dissolved in methylene chloride at a concentration of 5 wt%, filtered through a 0.1 μm filter, and the transmittance was measured. Transmittance at 600 nm is 10
The measurement was performed using a cm liquid cell. Results of measurement 98.
It was 1%.

This polycarbonate is used as a core material and an ethylene-tetrafluoroethylene copolymer is used as a clad material, and these resins are supplied to a double spinning head at 290 ° C.
Spun in. The obtained plastic optical fiber had a core diameter of 0.95 mm and a clad thickness of 0.04 mm.
The transmission loss of the obtained plastic optical fiber is 1100.
db / km and the transmission loss after 1 week at 140 ° C is 1300
It was db / km.

Example 2 Bisphenol A-biphenol type polycarbonate was produced according to the following formula.

[0030]

[Chemical 7]

To a 1 liter flask equipped with a stirrer and a thermometer, 625 ml of methylene chloride was added, and while stirring,
35.3 g of bisphenol A bischloroformate was added and dissolved. Further, 125 ml of ion-exchanged water was added thereto, and then a solution in which 18.6 g of biphenol was dissolved in 228.6 g of a 3.5% sodium hydroxide aqueous solution was added dropwise at 20 to 25 ° C. over 1 hour while sufficiently stirring.

After dropping, stirring was continued at the same temperature, and after 4 hours, 2
After adding 14.3 g of an 8% aqueous sodium hydroxide solution, the mixture was further stirred for 5 hours until the molecular weight became 60000 (GPC, converted to polystyrene). The stirring was stopped and the mixture was allowed to stand. The post-treatment was performed in the same manner as in Example 1. Yield 36.7 g (yield 79%) The obtained polycarbonate was ¹ H--N in the same manner as in Example 1.
According to MR, it was found to be an alternating copolymer having the structure of formula (I). This polycarbonate had a melting point at 254 ° C. If this is raised to a temperature above the melting point and rapidly cooled, amorphization occurs and the melting point does not appear, and the glass transition point is 16
Appeared at 9 ° C.

This polycarbonate is used as a core material and an ethylene-tetrafluoroethylene copolymer as a clad material, and these resins are supplied to a double spinning head at 290 ° C.
Spun in. The obtained plastic optical fiber had a core diameter of 0.95 mm and a clad thickness of 0.04 mm.
The transmission loss of the obtained plastic optical fiber is 1100.
db / km and the transmission loss after 1 week at 140 ° C is 1300
It was db / km.

Example 3 Bisphenol AF-biphenol type polycarbonate was synthesized according to the following formula.

[0035]

[Chemical 8]

To a 1-liter flask equipped with a stirrer and a thermometer, 625 ml of methylene chloride was added, and while stirring,
31.1 g of biphenol bischloroformate was added and dissolved. Further, 125 ml of ion-exchanged water was added thereto, and then a solution in which 33.6 g of bisphenol AF was dissolved in 228.6 g of a 3.5% sodium hydroxide aqueous solution was added dropwise at 20 to 25 ° C. for 1 hour while sufficiently stirring.

After the dropping, stirring was continued at the same temperature, and after 7 hours, the molecular weight became 30,000 (GPC, polystyrene conversion), and the stirring was stopped and the mixture was allowed to stand. The aqueous layer is separated, and the methylene chloride layer is washed with deionized water, 1% hydrochloric acid, deionized water,
After azeotropic dehydration, it was filtered with a 0.1 μm filter.
It was then poured into 1.2 liters of methanol,
The precipitated crystals were filtered and dried. Yield 42.5 g (yield 74%) It was confirmed from ¹ H-NMR that the obtained polycarbonate was an alternating copolymer. δ (ppm): 7.35 (d, 4H), 7.37 (d,
4H) 7.47 (d, 4H), 7.61 (d, 4H) This polycarbonate had a melting point at 261 ° C.
Further, when the temperature was raised to a temperature equal to or higher than the melting point and rapidly cooled, amorphization occurred, no melting point appeared, and a glass transition point appeared at 183 ° C.

This polycarbonate was mixed with methylene chloride to give 5 parts.
It was dissolved at a concentration of wt%, filtered through a 0.1 μm filter, and then the transmittance was measured. The transmittance was 600 nm and the measurement was performed using a 10 cm liquid cell. The measurement result was 98.4%.

This polycarbonate is used as a core material and an ethylene-tetrafluoroethylene copolymer as a clad material, and these resins are supplied to a double spinning head at 290 ° C.
Spun in. The obtained plastic optical fiber had a core diameter of 0.95 mm and a clad thickness of 0.04 mm.
The transmission loss of the obtained plastic optical fiber is 1200.
db / km and the transmission loss after 1 week at 140 ° C is 1300
It was db / km.

[0040]

Industrial Applicability The plastic optical fiber of the present invention comprises a polycarbonate having a structure of the above formula (I) whose molecular weight is controlled between 20,000 and 100,000 as a core material of the fiber, and has extremely high heat resistance. Also, it has an excellent effect that the transmission loss is small.

Claims (1)

[Claims] 1. A core material has the formula: (Each of R ₁ and R ₂ wherein hydrogen atom, a lower alkyl group or a trifluoromethyl group. Further R _1, R
_Two may together form a ring. n shows a positive number. ) Has a main chain and an average molecular weight of 200
A plastic optical fiber, which is formed of a modified polycarbonate copolymer having a size of 00 to 100,000.