JPH01109308A - Heat-resistant sheath composition for optical fiber - Google Patents

Abstract

PURPOSE:To improve the heat resistance of a UV curing type sheath compsn. by incorporating specific alkyl mercaptan as a thermal stabilizer. CONSTITUTION:The title compsn. contains a compd. contg. a fluorined alkyl group having >=1 H and (meth)acryloyl group, multifunctional monomer, oligomer, photopolymn. initiator, and the alkyl mercaptan (A) as the thermal stabilizer. The alkyl mercaptan having >=2 mercapto groups in one molecule is preferably used as the component A and trimethylol propathioglycolate, etc., are usable. Since this compsn. can be made into a liquid state at room temp., the compsn. is capable of forming a sheath layer at room temp. and is curable in a short period of time by UV irradiation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an ultraviolet curable sheath material composition that can be used as a sheath material for optical fibers.

[Conventional technology]

Physical properties required of optical fibers include low refractive index, high transparency, and excellent mechanical strength and heat resistance. Examples of conventionally used sheath materials include vinylidene fluoride polymers, fluoroalkyl methacrylate polymers, and silicone resins.

Of the physical properties required for the sheath material, all of these materials were almost satisfactory in terms of physical properties other than heat resistance, but they were insufficient in terms of heat resistance.

[Means for Solving the Problems] ^ The present invention solves this drawback by combining a fluorinated alkyl group having at least one hydrogen atom and a 7-acryloyl group or a methacryloyl group in one molecule. Compound (5k), polyfunctional monomer (b), oligomer (c)
, a photopolymerization initiator (d) and an alkyl mercaptan having one or more mercapto groups in one molecule as a thermal stability rule (
A heat-resistant sheath material composition for optical fibers characterized by containing e).

The composition of the present invention is characterized by being cured by ultraviolet light. Since the ultraviolet curable sheath material has a fast curing speed, it is compatible with the high-speed core component drawing process, and high productivity can be obtained. Furthermore, since it is cured by ultraviolet rays, it has excellent stability and workability, and sufficient strength can be obtained after curing. This polymer forms a three-dimensional network through crosslinking and is imparted with heat resistance, and since the composition of the present invention contains a heat stabilizer, the heat resistance is significantly improved.

Examples of the compound (a) having a fluorinated alkyl group containing at least one hydrogen atom and an acryloyl group or a methacryloyl group in one molecule used in the present invention include fluoroalkyl methacrylates and fluoroalkyl acrylates. . For example, in fluoroalkyl methacrylate, the ester moiety has an electron-withdrawing group,
The generation of this monomer may cause foaming and cracks. In addition, unlike the zipper-type depolymerization of methacrylate polymers, fluoroalkyl acrylates have methine protons in the polymer main chain, so they undergo decomposition initiated by this hydrogen abstraction, resulting in the generation of unsaturated The coloring of the polymer progresses due to the presence of these groups. The composition of the present invention aims to improve heat resistance by using a mercapto group as a radical scavenging group to capture radical initiation points generated when a polymer made of such monomers is heat-treated. It is.

Individual examples of component (a) include the following compounds. Trifluoro CI (meth)acrylate, 2.2.5
．． 5-tetrafluoropropyl (meth)acrylate,
2,2,3,3,3-pentafluoropropyl (meth)
acrylate), 2-)lifluoromethyl, 5,5,5
-Trifluoromethyl (meth)acrylate, 2-trifluoromethyl-2,3,3,5-tetrafluoropropyl (meth)acrylate, 2.2.5.4,4.4-
Hexafluorobutyl (meth)acrylate, 1-methyl-2,2,5,4,4,4-hexafluorobutyl (
meth)acrylate, 1,L2,2-tetrahydroperfluorodecyl (meth)acrylate, 1,1.2.2
-tetrahydro-9-trifluoromethylperfluorodecyl (meth)acryle), 1,1-dihydroperfluorobutyl (meth)acryle), 1,1-dimethyl-2,2,S,S-tetrafluoropropyl (meth)acrylate, 1,1-dimethyl-2,2,5°5.4.
4,5.5-octafluoropentyl (meth)acrylate, 1.1-dimethyl-2,2,S, 4.4.4-hexafluorobutyl (meth)acrylate, and the like.

Examples of the polyfunctional monomer (b) include the following compounds. Examples of difunctional monomers include 1,3-butanediol diacrylate), 1,4-butanediol diacrylate, 1,6-hexadiol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, and polyethylene glycol. diacrylate, tripropylene glycol diacrylate,
Hydroxypivalic acid ester neopentyl glycol diacrylate, hydroxypivalic acid ester neopentyl glycol derivative diacrylate, neopentyl glycol modified trimethylolpropane diacrylate, trifunctional monomers include trimethylolpropane triacrylate, pentaerythritol triacrylate , dipentaerythritol monohydroxypentaacrylate as a pentafunctional monomer, dipentaerythritol hexaacrylate as a hexafunctional monomer, and the like. It is also possible to use a mixture of two or more of these polyfunctional monomers.

Oligomer (e) determines the basic physical properties after curing, and for example, poly(meth)acrylate-based oligomers such as polyester poly(meth)acrylate, epoxy poly(meth)acrylate, and polyurethane poly(meth)acrylate are used. preferable. Furthermore, by introducing fluorine atoms into the structure, it is possible to lower the refractive index of the cured product, suppress water absorption and hygroscopicity, and improve physical properties such as solvent resistance. Since such oligomers generally have a high viscosity, it is preferable to adjust the viscosity by diluting them with a reactive monomer for the purpose of improving workability. As such a reactive monomer, for example, the following compounds are used. (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate,
Butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, decyl (meth)acrylate, stearyl (meth)acrylate, n-hexyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl ( Meta)
acrylate, butoxyethyl (meth)acrylate,
methoxydiethylene glycol (meth)acrylate,
ethoxydiethylene glycol (meth)acrylate,
Cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol ( meth)acrylate, methoxypolypropylene glycol (meth)acrylate,
Phenoxyethyl (meth)butarylate, phenoxypolyethylene glycol (meth)acrylate, alkylphenoxyethyl (meth)acrylate, alkylphenoxypolyalkylene glycol (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, tetrahydrofurfuryl Oxypolyalkylene glycol (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyalkyl (meth)acrylate, dicyclopentenyloxypolyalkylene glycol (meth)acrylate, 2-hydroxyalkyl (meth)acryloyl phosphate, acetic acid Vinyl, vinyl propionate, etc.

Examples of the photopolymerization initiator (d) include the following compounds. Carbonyl compounds such as benzine, benzoin isobutyl ether, benzophenone, p-chloropentuphenone, p-methoxybenzophenone, etc. Sulfur compounds such as tetramethylthiuram monosulfide,
Tetramethylthiuram disulfide, azo compounds such as azobisisobutyronitrile, azobis-2,4-
Peroxide compounds such as dimethylvaleronitrile, benzoyl peroxide, ditertiary butyl peroxide, and the like. Preferred photopolymerization initiators include the following compounds.

4'-isopropyl-2-hydroxy-2-methylpropionphenone, 2-hydroxy-2-methylglopiophenone, α,α-dichloro-4-phenoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, benzyl dimethyl ketal, 2 .2-Jethoxyacetophenone, chlorothioxanthone, 2-isopropylthioxanthone, Kayacure DI'rX (titoxanthone compound manufactured by Nippon Kayaku Co., Ltd.), Kayacure MBP (
benzophenone compound manufactured by the same company), Juvecryl P36 (dicarally polymerizable high molecular weight benzophenone manufactured by UCB, Peru), etc.

The composition of the present invention may contain a photosensitizer. Examples of the photosensitizer include the following compounds. aliphatic amines, aromatic amines, ureas such as 0-tolylthiourea, sulfur compounds such as sodium diethyldithiophosphate, J-benzylinthiuronium-p-)luenesulfonate, nitrites such as N,N-disubstituted-p-amino Benzonitrile, phosphorus compounds e.g.
-butylphosphine, nitrogen compounds such as N-nitrosohydroxylamine derivatives. Preferred photosensitizers include the following compounds. Ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate,
4.4'-bisdiethylaminobenzophenone, Yupecryl P104 (radical polymer polymerized tertiary amine manufactured by UCB, Belgium), N-methyljetanolamine, diethylaminoethyl methacrylate, triethylamine, etc.

The content of the photopolymerization initiator and photosensitizer is 0.01 to 0.01 to
10% by weight, preferably 1-5% by weight. If the content is higher than this, storage stability will decrease and it will be difficult to dissolve.

Examples of the alkylmercaptan (e) having one or more mercapto groups in one molecule include the following compounds. Tertiary butyl mercaptan, hydroxyethyl mercaptan, thioglycolic acid, β-mercaptopropionic acid, n-hexyl mercaptan, n-octyl mercaptan, ammonium thioglycolate, monoethanolamine thioglycolate, ethyl thioglycolate,
Butyl thioglycolate, octyl thioglycolate,
Methoxybutyl thioglycolate, ethoxyethylthioglycolate, butoxyethylthioglycolate, phenoxyethylthioglycolate, triethylene glycol dimethylcaptan, trimethylolpropanethioglycolate, pentaerythritol tetrathioglycolate, trimethylolpropane tris- β-mercaptoglopionate, pentaerythritol tetrathiopropionate, mercaptoethyl borate, polyfunctional polymers produced from polyglycidyl methacrylate and thioglycolic acid, and the like.

The content of the alkyl mercaptan (e) is preferably 0.05 to 50 parts by weight per 100 parts by weight of the sheath material layer and the acid.
．． It is 1 to 10 parts by weight.

Compound (a) and oligomer (e) of the resin composition of the present invention
) is preferably 99=1 to so:so by weight.

Further, the proportion of the polyfunctional monomer (b) is preferably 50 parts by weight or less based on 100 parts by weight of the total amount of the compound (a) and the oligomer (c).

Since the resin composition of the present invention can be made liquid at room temperature, the sheath material layer can be formed at room temperature. The resin composition can be applied by passing the core fiber through a goo filled with the resin composition. Next, by irradiating the fiber coated with the resin composition with ultraviolet rays, curing can be completed in a short time. Examples of ultraviolet light sources include xenon lamps, low-pressure mercury lamps, high-pressure mercury lamps, and ultra-high-pressure mercury lamps.

Example 1 L2s2- ) 9 Fluoroethyl A II) 1/-) 9
0 parts by weight, polyurethane polyacrylate resin (manufactured by Toagosei Kagaku Kogyo Co., Ltd., trade name Aronix M-1200)
10 parts by weight of trimethylolpropane triacrylate, 2 parts by weight of benzyl dimethyl ketal (manufactured by Ciba Geigy, trade name Irgacure 651), and 1 part by weight of trimethylolpropane glycolate were mixed at room temperature to form a photocurable resin composition. I got something. This resin composition was cast onto a glass plate to a thickness of 100 μm and tightly covered with a polyester film to prepare a sample.

This sample was exposed to light at 80 W/m for about 1 second using an ultraviolet exposure device equipped with a high-pressure mercury lamp to obtain a cured product. This cured product was a transparent and flexible film with a refractive index of 1.419. There was no change in transparency even after this film was heat treated at 200° C. for 100 hours.

Example 2 Diameter 200μ obtained from quartz glass with a refractive index of 1.46
After applying the ultraviolet curable resin composition of Example 1 as a sheath component onto the surface of the core component using a die, immediately irradiation energy of 80 W/m was applied as a core component.
A sheath component was formed by passing cIn at a distance of about 10 cWI from an ultraviolet irradiation light source, and a plastic clad quartz fiber having a core-sheath structure was obtained.

The transmission loss of this fiber was 8 dB/km at a wavelength of 850 nm. This was heated to 150℃ for 1000
The transmission loss after time heat treatment was good at 10 dB at wavelength 850 nm and 4 m.

Examples 3 to 9 A cured product was obtained in the same manner as in Example 1 except that the heat stabilizer of the photocurable resin composition of Example 1 was changed as shown below. The films of all photocurable resin compositions were transparent and flexible. Further, there was no change in transparency even after heat treatment at 150°C for 1000 hours. The results are also shown in the table. In addition, Y and engineering (yellow index value) in the table were based on ASTM D 1925.

Example 10 A cured product was obtained in the same manner as in Example 1 using the following composition.

Both films were transparent and flexible. Further, there was no change in transparency even after heat treatment at 150°C for 1000 hours. The refractive index and Y and I values are also shown.

Composition: Polyester acrylate resin (Aronix 801 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) 10 parts by weight 2
．． 2.2-trifluoroethyl acrylate 4
0 IH, IH, 2H, 2H-heptadecafluorodecyl acrylate 3
0 Trimethylolpropane triacrylate
10 〃1-Hydroxycyclohexylphenylketone 2 〃Trimethylolpropane tris-β-mercaptopropionate
1 Refractive index: 1.401 Y, I (initial value): 2.1 Y, engineering (after heat treatment): 2.9 Comparative example A sample was prepared in the same manner as in Example 1 without adding alkyl mercaptan. When heat treated at 150°C for 1000 hours, Y and I were 56 and turned pale yellow. Furthermore, when a plastic clad quartz fiber was produced in the same manner as in Example 2 and heat treated at 150° C. for 1000 hours, the transmission loss was as follows, and an increase in loss due to heat treatment was observed.

Transmission loss (initial value): 8 dB/km (after heat treatment): 28 dB/km

Claims (1)

[Scope of Claims] 1. A compound (a) having a fluorinated alkyl group having at least one hydrogen atom and an acryloyl group or a methacryloyl group in one molecule, a polyfunctional monomer (b), an oligomer ( c) A heat-resistant sheath material composition for an optical fiber, comprising a photopolymerization initiator (d) and an alkyl mercaptan having one or more mercapto groups in one molecule (e) as a heat stabilizer. 2. The heat-resistant sheath material composition for optical fibers according to claim 1, characterized in that an alkyl mercaptan having two or more mercapto groups in one molecule is used as a heat stabilizer. 3. The heat-resistant sheath material composition for optical fibers according to claim 1, wherein the amount of alkyl mercaptan is 0.05 to 50 parts by weight based on 100 parts by weight of the sheath material composition.