JPH0522203B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a light transmission fiber using a curable fluorine-containing copolymer as a sheath material, and more specifically, it relates to a light transmission fiber using a curable fluorine-containing copolymer as a sheath material, and more specifically, it relates to a light transmission fiber using a curable fluorine-containing copolymer as a sheath material. The present invention relates to an optical transmission fiber whose sheath material component is a curable fluorine-containing copolymer containing a hydroxy group-containing allyl ether as an essential component. Advances in semiconductor lasers and optical devices have brought optical communication systems into practical use, and the development of various optical technologies has become active. The basis of this optical communication system is optical transmission fiber, and various optical cables have been commercialized using materials such as quartz, multicomponent glass, and plastic. (Prior art) Quartz and multicomponent glass optical transmission fibers are mainly used for long-distance transmission because of their low optical transmission loss, and plastic optical transmission fibers can be made into large diameters and have excellent workability. Because of this, it has been commercialized for short-distance use. Also, recently,
Composite optical transmission fibers with a quartz or glass core and a plastic sheath are expected to be used for medium-distance transmission. As the sheath material for the optical transmission fibers mentioned above, glass-based materials with low refractive index, silicone-based resins, and fluorine-based resins are often used. In addition, water resistance,
It is also attracting attention from the perspective of weather resistance. (Problems to be Solved by the Invention) The following items are required for the sheath component of the optical transmission fiber. (1) It is inexpensive (2) It has a heat softening temperature of 100℃ or higher (3) It has excellent processability as an optical transmission fiber (4) It has excellent adhesion to the core material ( 5) Few impurities, (6) Weather resistance, (7) Low absorption, (8) High transparency, and (9) Low refractive index, etc., and it completely satisfies these requirements. There is little pod material. For example, JP-A-49-107790, JP-A-49-
108321, JP-A-49-115556, JP-A-49-129545,
Unexamined Japanese Patent Publications 1972-156450, 1972-122453, 1972
-82250, JP-A-52-148137, and JP-A-59-
The monomers of the fluorine-based (meth)acrylic resins disclosed in No. 116701 and the like are expensive, so the resin itself is also expensive. Furthermore, many have thermal softening temperatures of 100°C or lower, which poses thermal problems. On the other hand, vinylidene fluoride copolymers are examples of resins that can be produced at low cost. For example, the resins disclosed in JP-A-51-52849 and JP-A-53-60242 are considered to be produced relatively inexpensively, but they have drawbacks in melting temperature, melt viscosity, and crystallinity. Since the transparency of the resin itself is deteriorated, optical transmission loss is reduced. (Means for Solving the Problems) As a result of extensive research, the present inventors have found that a chlorotrifluoroethene copolymer, a fatty acid vinyl ester or a fatty acid isopropenyl The present inventors have discovered that a curable resin containing an ester and a hydroxy group-containing allyl ether as essential components satisfies the above-mentioned requirements, and have completed the present invention. The copolymer of chlorotrifluoroethylene and fatty acid vinyl ester exhibits high transparency over a wide wavelength range, and is relatively easily dissolved in organic solvents by heating, as disclosed in British Patent No. 888014.
No., WHTomas, etc. (J. Polymer Science, 11
(5), 455 (1953)). but,
Since thermal stability is also a necessary condition for optical transmission fibers, the present inventors used a monomer with a functional group capable of causing a curing reaction, that is, a hydroxy group-containing allyl ether, as the monomer. We attempted to copolymerize it and apply it to optical transmission fibers as a hardening type resin. The present invention will be described in detail below. The fluorine-containing copolymer that is the sheath component of the present invention is
Chlorotrifluoroethylene and the formula

[Formula] (However, R ₁ = H or -CH ₃ , R ₂ = -C _o H _2o+1 ; n = an integer of 1 to 12) fatty acid vinyl ester or fatty acid isopropenyl ester, and the formula CH ₂ =CH- _CH2 -O- _R3 (however, _R3 =(- _CH2CH2O ) _-nH ; _m =an integer of 1 to 6) is an essential component of hydroxy group-containing allyl ether; amounts of 25 to 75 mol%, 10 to 70 mol%, and 3 to 40 mol%, respectively;
Preferably, the range is 40-70 mol%, 20-50 mol%, and 5-30 mol%. In addition to the above-mentioned essential components, 0 to 20 mol% of other comonomers described below may be added. The content of chlorotrifluoroethylene can be arbitrarily changed depending on the amount of each monomer added, but if it is too high, the solubility of the copolymer in organic solvents will decrease, and the copolymer will have problems during polymerization. The yield also decreases. On the other hand, if the amount is small, it is unfavorable from the viewpoint of physical properties such as weather resistance and chemical resistance, and the refractive index may also become high. The fluorine-containing copolymer can be produced by any conventional method such as solution polymerization, emulsion polymerization, suspension polymerization, or bulk polymerization in the presence of a radical initiator. Usable fatty acid vinyl esters include vinyl acetate, vinyl lactate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl isocaproate, vinyl bivaricate, vinyl caprylate, etc., but the number of carbon atoms in the alkyl group is 1 to 1. 3 is preferred. Examples of fatty acid isopropenyl esters include isopropenyl acetate and isopropenyl propionate. As the hydroxy group-containing allyl ether, ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, triethylene glycol monoallyl ether, etc. can be used, but (-CH ₂ CH ₂ O
) _-n units are preferably m=1 to 2. In addition to the essential components, other monomers include acrylic acid esters such as hydroxyethyl (meth)acrylate, methyl (meth)acrylate, and glycidyl (meth)acrylate, acrylamides such as acrylamide, N-methylolacrylamide, and ethyl vinyl ether. , vinyl ethers such as butyl vinyl ether, vinyl chloride, fluorine-containing (meth)acrylic acid esters, etc. can be copolymerized. Since the copolymer obtained in the above manner has active hydrogen in its molecular chain, it can contain compounds that react with active hydrogen, such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and naphthylene diisocyanate. It can be hardened by adding polyvalent isocyanates such as , tolidine diisocyanate, hexamethylene diisocyanate, or lysine diisocyanate, melamine, urea resins, polybasic acids, or their anhydrides. The amount of polyvalent isocyanate added is 1 n-valent polyvalent isocyanate per n molecules of hydroxy group-containing allyl ether in the polymer.
The amount of molecules is appropriate, and other curing agents are appropriately selected depending on the state of melt spinning. In the present invention, the material used as the core material can be any material used for ordinary optical transmission fibers. For example, quartz-based material is used for long-to-medium distance transmission, and for short-distance transmission, Methacrylic acid ester polymers, styrene polymers, etc. can be used. Immediately after melt-spinning a core material of quartz or plastic, the optical transmission fiber is passed through an organic solution of the fluorine-containing copolymer or an organic solution of the fluorine-containing copolymer containing a curing agent, and then, The sheath material coating is applied by evaporating the organic solvent, drying and curing. This makes it possible to obtain an SI type optical transmission fiber. The organic solvents used include cyclic ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as benzene and toluene, ethyl acetate,
Esters such as butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, dimethyl formamide,
Examples include nitrogen-containing solvents such as dimethylacetamide and pyridine, halogen-containing solvents such as 1.1.1-trichloroethane and trichloroethylene, and mixed solvents of the above-mentioned solvents. Drying and curing can be carried out under normal pressure or reduced pressure at a temperature ranging from room temperature to about 300°C. Note that from the viewpoint of productivity, it is desirable to carry out the process at a high temperature. The optical transmission fiber obtained as described above showed no change in appearance for more than 3000 hours in an accelerated weather resistance test using a weatherometer, and no decrease in transmission loss was observed. It also has thermal stability and resistance to acids, alkalis, water, and the like. In addition, the fluorine-containing copolymer used as the pod material has a wavelength of 400nm.
It is possible to provide an optical transmission fiber with no absorption from 2500 nm to near infrared region, and low transmission loss over a wide wavelength range. The present invention will be explained below with reference to Examples, but is not limited thereto. Example 1 38.7 g of vinyl acetate (VAc), 30.6 g of ethylene glycol monoallyl ether (EGMAE), 645 ml of water, 75 ml of tertiary butyl alcohol (trBuOH), and methyl cellulose were placed in a stainless steel autoclave with an internal volume of 1.4 and equipped with a magnetic stirrer. (Mc), 3.0 g of sodium borate, and 0.75 g of diisopropyl peroxydicarbonate (IPP) as a radical initiator were charged, and the inside of the autoclave was purged with nitrogen gas three times. Then,
After cooling and degassing the autoclave, 87.5 g of chlorotrifluoroethylene (CTFE) was introduced into the autoclave (CTFE/VAc/EGMAE=50/30/
20 molar ratio), and the temperature was gradually raised. After polymerization was carried out at 40° C. for 24 hours, unreacted CTFE was removed, the autoclave was opened, and the copolymer was washed with water and dried to obtain 91 g of a copolymer. The intrinsic viscosity of this copolymer in tetrahydrofuran (THF) at 30°C was 0.31 dl/g. 40g of this copolymer and dibutyltin dilaurate
Polyvalent isocyanate curing agent, 20 g of Coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.) ^, 10 g of methyl isobutyl ketone,
A solution to which 12 g of a mixed solution of 10 g of toluene was added,
It was spread on a Teflon plate. Thereafter, the solvent was evaporated and heated at 100°C to obtain a film with a thickness of 100 μm.
The light transmittance of the obtained film (polymer 1) is shown in FIG. 1, and other properties are shown in Table 1. Example 2 In the same manner as in Example 1, the monomers of the charging composition were changed to CTFE/VAc/EGMAE=50/45/5, 60/
Polymerization was carried out at molar compositions of 30/10 and 60/20/20, and cured according to Example 1 to obtain a film with a thickness of 100 μm. The resulting resin films were designated as polymers 2, 3, and 4, respectively, and their properties are shown in Table 1. When producing the film, the solvent was changed to ethyl acetate and butyl acetate, but the properties of the films obtained were almost the same. Example 3 In the same manner as in Example 1, CTFE, vinyl caproate (VCa), and EGMAE were mixed at 50/30/20, and CTFE,
Isopropenyl acetate (iso-PAc), EGMAE
Polymerization was carried out at a molar composition of 50/30/20. Further, the film was cured according to Example 1 to obtain a film having a thickness of 100 μm. The obtained resin films were designated as Polymers 5 and 6, respectively, and their properties are shown in Table 1.

[Table] Example 4 120 g of fluorine-containing copolymer CTFE/VAc/EGMAE (50/30/20 charging molar ratio) obtained by the same method as Example 1, and 3.6× dibutyltin dilaurate
10 ^-3 g dissolved in 60 g of methyl isobutyl ketone and 60 g of toluene, 50 g of Coronate EH used in Example 1 and 25 g of methyl isobutyl ketone were added.
A solution was prepared by adding 36 g of a mixed solution of 25 g of toluene and 25 g of toluene. Next, quartz glass with an outer diameter of 125 μm is spun as the core material of the optical transmission fiber using a high-frequency induction heating furnace, passed through the fluorine-containing copolymer solution at a point 3 m directly below it, and then dried at 60°C. passed through the vessel.
The film was further passed through a heat treatment machine at 200°C and then wound up. The average coating thickness of the obtained pod material was 14 μm. The core material and the sheath material adhered well, no phenomena such as peeling were observed, and the flexibility was excellent. Also
The transmission loss found with a 623.8nm He-Ne laser is
It was 40dB/Km. Example 5 120 g of fluorine-containing copolymer CTFE/VAc/EGMAE (50/30/20 molar ratio) obtained in the same manner as in Example 1, and 3.6× dibutyltin dilaurate
10 ^-3 , 55g of methyl isobutyl ketone and toluene
50 g of Coronate EH used in Example 1, 25 g of methyl isobutyl ketone,
A solution was prepared by adding 36 g of a mixed solution of 25 g of toluene. Next, quartz glass with an outer diameter of 250 μm is spun as the core material of the optical transmission fiber using a high-frequency induction heating furnace, passed through the fluorine-containing copolymer solution 3 m directly below it, and then dried at 60°C. passed through the vessel.
The film was further passed through a heat treatment machine at 200°C and then wound up. The average coating thickness of the obtained sheath material was 18 μm. The core material and the sheath material adhered well, no phenomena such as peeling were observed, and the flexibility was excellent. Also,
The transmission loss found with a 623.8nm He-Ne laser is
It was 32dB/Km. In addition, the above-mentioned optical transmission fiber once coated with sheath material,
Pass it through the fluorine-containing copolymer solution again, and then
It was passed through a dryer at 60°C. The film was further passed through a heat treatment machine at 200°C and then wound up. The coating thickness of the sheath material was 40 μm on average, and the transmission loss determined by a 623.8 nm He-Ne laser was 31 dB/Km. Example 6 Fluorine-containing copolymer obtained by the same method as Example 1
CTFE/VAc/EGMAE (60/30/10 molar ratio)
Coronate used in Example 1 was added to a solution of 120 g of dibutyltin dilaurate and 3.6×10 ^-3 dissolved in 60 g of methyl isobutyl ketone and 60 g of toluene.
A solution was prepared by adding 21 g of a mixed solution of 50 g of EH, 25 g of methyl isobutyl ketone, and 25 g of toluene. Next, as the core material of the optical transmission fiber, quartz glass with an outer diameter of 125 μm was spun using a high-frequency induction heating furnace.
The fluorine-containing copolymer solution was passed through the solution at a point 3 m directly below it, and then passed through a dryer at 60°C. The film was further passed through a heat treatment machine at 200°C and then wound up. The average coating thickness of the obtained pod material was 14 μm. The core material and the sheath material adhered well, no phenomena such as peeling were observed, and the flexibility was excellent. Also
The transmission loss found with a 623.8nm He-Ne laser is
It was 38dB/Km. Example 7 Fluorine-containing copolymer CTFE, vinyl caproate,
EGMAE was polymerized at a charging molar ratio of 50/30/20. 90 g of the obtained copolymer and 2.7×10 ^-3 g of dibutyltin dilaurate were mixed with 105 g of methyl isobutyl ketone.
g and 25 g of methyl isobutyl ketone, 25 g of toluene, and coronate in a solution dissolved in 105 g of toluene.
A fluorine-containing copolymer solution was prepared by adding 9.5 g of a mixed solution of 50 g of EH. Next, as the core material of the optical transmission fiber, quartz glass with an outer diameter of 125 μm was spun using a high-frequency induction heating furnace.
The fluorine-containing copolymer solution was passed through the solution at a point 3 m directly below it, and then passed through a dryer at 60°C. After further heat treatment at 200°C, winding was performed. The average coating thickness of the obtained pod material was 15 μm. Furthermore, the transmission loss determined using a 623.8 nm He-Ne laser was 40 dB/Km. Example 8 Fluorine-containing copolymer CTFE/VAc/EGMAE
(50/30/20 charge molar ratio) 120 g and dibutyltin dilaurate 3.6 x 10 ^-3 g were dissolved in 36 g of methyl isobutyl ketone and 36 g of toluene, and 50 g of Coronate EH, 25 g of methyl isobutyl ketone,
A fluorine-containing copolymer solution was prepared by adding 36 g of a mixed solution of 25 g of toluene. Next, polymethyl methacrylate (trade name: Acrypet manufactured by Mitsubishi Rayon; melt index value 4 g/10 min) was melt-spun at 220°C as a core material.
A filament with a diameter of 0.8 mm was obtained. This filament was passed through the fluorine-containing copolymer solution and then passed through a dryer at 60°C. moreover
After heat treatment at 120°C, winding was performed to obtain a plastic optical transmission fiber. The average coating thickness of the obtained sheath material was 26 μm. The transmission loss determined using a 623.8nm He-Ne laser was 160dB/Km.

[Brief explanation of the drawing]

FIG. 1 shows the light transmittance of the film in Example 1.

Claims (1)

_[ Claims] 1. _{Chlorotrifluoroethylene} and _{a fatty acid} represented by the formula: vinyl ester or fatty acid isopropenyl ester, and the formula _CH2 =CH- _CH2 -O- _R3 (however,
A fluorine-containing copolymer containing a hydroxy group-containing allyl ether represented by R ₃ = (-CH ₂ CH ₂ O)- _n H; m = an integer of 1 to 6 as an essential component is used as the sheath material. optical transmission fiber. 2 Polyvalent isocyanate, fluorine-containing copolymer,
The optical transmission fiber according to claim 1, characterized in that a fluorine-containing film cured by adding melamine, urea resin, polybasic acid, etc. is used.