JP2541159B2 - Optical transmission fiber - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission fiber, which uses an active energy ray-curable resin composition which gives a cured resin which has a low refractive index and is tough and transparent upon irradiation with an active energy ray as a sheath component. Regarding fiber.

[0002]

Fluorine-containing monomers have been used as high-performance materials in various fields because they generally have high chemical resistance, weather resistance, water / oil repellency, surface lubricity and the like. In recent years, attention has been paid to its optical characteristics, that is, a low refractive index, and its use as a sheath material of an optical transmission fiber has been activated.

[0003] Optical transmission fibers are broadly classified into inorganic glass-based and synthetic resin-based ones, each of which is composed of a core portion having high transparency and a high refractive index, and a sheath portion having a relatively low refractive index. I have. Conventionally, as a method of forming a sheath portion,
Coatings of low refractive index silicone compounds or fluoropolymers have been proposed and practiced. For example, (1) a method of applying a silicone-based resin to a drawn quartz-based core wire and forming a sheath portion of the silicone resin by thermosetting,
(2) A polymer of a fluorinated alkyl group-containing (meth) acrylate obtained by a polymerization method such as solution polymerization, bulk polymerization, or emulsion polymerization, with a core material such as poly (methyl methacrylate) or poly (styrene) , Copolymers of fluorinated alkyl group-containing (meth) acrylate with other comonomers, or poly (tetrafluoroethylene), poly (vinylidene fluoride / tetrafluoroethylene), poly (vinylidene fluoride / hexafluoropropylene), etc. And a fluorinated polymer of which the sheath portion is formed (Japanese Patent Publication No. 43-8978, Japanese Patent Publication No. 56-8321, Japanese Patent Publication No. 56-8322, and Japanese Patent Publication No. 56-8323). JP-A-59-84203, JP-A-59-84204, JP-A-59-98116, JP-A-147011, HirakiAkira 59 over No. 204002),
(3) A method in which a fused or solution of a fluoropolymer such as poly (vinylidene fluoride / tetrafluoroethylene) is applied to a fibrous shaped quartz or plastic core wire to form a sheath. (Japanese Patent Publication Sho 53-21660
No. 56-41966).

However, among these proposals, (1)
Although the silicone resin described in 1) has excellent heat resistance, it has poor oil resistance, and has the drawback that it swells when immersed in mineral oil or the like, causing a change in the refractive index and peeling from the core wire. For this reason, the optical transmission fiber having a silicone resin as a sheath material is limited in use, and it is unsuitable for use in oil such as transformers and thyristors.

Further, the silicone resin composition before curing has a short pot life and its viscosity increases with time. Therefore, in order to coat the core wire with a constant film thickness, the coating speed and the temperature of the atmosphere are controlled. There was a work drawback that I had to do.

Furthermore, the refractive index of the silicone resin is limited to about 1.40, which is insufficient in terms of performance as a sheath material for a large-diameter optical transmission fiber required in accordance with the increase in communication capacity. There is a drawback that.

On the other hand, the fluorine-containing polymers described in (2) and (3) have a low refractive index of about 1.36. Therefore, as a sheath material for a large-diameter optical transmission fiber, a silicone-based resin is preferable. Is suitable.

However, in the conventional method of forming the sheath portion from the fluoropolymer as shown in (2) and (3), the core wire and the sheath portion are composite-spun at high temperature, and the fiber is also used. Since the core wire shaped like a wire is coated with the melt or solution of the fluoropolymer, the diameter of the core wire and the thickness of the sheath portion are likely to be uneven.

For this reason, there is a problem that light is scattered at a locally bent portion at the interface between the core portion and the sheath portion, and transmission loss is increased. Further, in the optical transmission fiber formed by these conventional methods, the adhesion between the core portion and the sheath portion is not always sufficient, and delamination is easily caused by various external factors such as bending, pressure change, temperature change, and the like. , Durability and the like.

Furthermore, in the method for producing an optical transmission fiber by applying the melt or solution of the fluoropolymer as shown in (2) and (3), it takes a long time to cure the sheath portion, and The solution coating method has drawbacks in productivity, safety, economic efficiency, etc., since the manufacturing process and equipment are complicated because the solvent must be completely removed out of the system.

[0011]

DISCLOSURE OF THE INVENTION The present invention relates to a sheath material which is satisfactory in terms of performance such as mechanical strength and adhesion, and is satisfactory in terms of productivity, safety, economy and the like in the production of optical transmission fibers. It is another object of the present invention to provide an optical transmission fiber having a sheath material having a lower refractive index, which enables a higher numerical aperture and a larger diameter.

[0012]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a fluorine-containing polymer having a fluorine atom content of 30% by weight or more and a fluorine-based reactive monomer. It has been found that a cured product of an active energy ray of a resin composition characterized by containing and is excellent in mechanical strength and adhesion to a core wire as compared with a sheath material of a conventional optical transmission fiber. .

Further, in a resin composition containing a fluorine-containing polymer having a fluorine atom content of 30% by weight or more and a fluorine-based reactive monomer, the degree of polymerization of the fluorine-containing polymer is Since the viscosity of the resin composition can be arbitrarily adjusted by adjusting the content of the resin composition and / or the content thereof, a resin composition having a viscosity that matches the coating equipment and the required coating thickness of the core wire can be easily prepared, and further the fluorine-containing content can be further improved. By increasing the content of fluorine atoms in the polymer, it is possible to further increase the numerical aperture and diameter of the optical transmission fiber, and to obtain a sheath material having a refractive index of about 1.33. The advantages were discovered and the present invention was completed.

That is, the present invention provides the following general formula (I) having a fluorine atom content of 30% by weight or more.

[0015]

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[Wherein Rf is a perfluoroalkyl group having 1 to 20 carbon atoms, a partially fluorinated aliphatic group, or an oxygen atom intervening in the main chain thereof, and R ₁ is H or C.
H _3, Cl, F or -X-Rf, X represents a divalent linking group. ] A polymer of a fluorine-containing (meth) acrylate (a) represented by the following, or an ester monomer (b) and / or a vinyl group of the fluorine-containing (meth) acrylate (a) and an α, β-ethylenically unsaturated dicarboxylic acid A copolymer with the containing monomer (c), a fluorine-containing (meth) acrylate (a) represented by the above general formula (I) and / or the following general formula (II)

[0017]

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[Wherein x is an integer of 1 to 2 and y is 4 to 12]
, R ₇ represents H, CH ₃ , Cl or F. ] An optical transmission fiber containing a fluorine-containing (meth) acrylate (d) represented by the formula (d) and having an active energy ray-curable resin composition as a sheath component, which gives a cured product having a refractive index of 1.44 or less. To do.

The active energy ray-curable resin composition according to the present invention contains essential components of a fluoropolymer (A) having a fluorine atom content of 30% by weight or more and a fluorine-based reactive monomer (B). Other than the above, a non-fluorine-based monomer (C), an additive (D), and a photopolymerization initiator (E) may be contained, if necessary.

The fluorine-containing polymer (A) has a fluorine atom content of 30 from the viewpoint of compatibility with the fluorine-based reactive monomer (B) and the non-fluorine-based monomer (C).
Fluorine-containing acrylate or methacrylate by weight% or more [hereinafter, the acrylate and the methacrylate are combined and abbreviated as (meth) acrylate. ] The polymer of (a) or a fluorine-containing (meth) acrylate (a),
Copolymer with one or more monomers selected from ester monomers (b) and / or vinyl group-containing monomers (c) of α, β-ethylenically unsaturated dicarboxylic acids such as fumaric acid and maleic acid. Is used.

Among these, the introduction of the ester monomer (b) of the α, β-ethylenically unsaturated dicarboxylic acid into the fluoropolymer (A) reduces the crystallinity of the fluoropolymer (A) and makes it transparent. Property, improved compatibility with the fluorine-based reactive monomer (B) and the non-fluorine-based monomer (C), and a cured resin obtained by irradiating the resin composition according to the present invention with active energy rays, that is, a sheath It is extremely effective in improving the transparency and flexibility of the material.

The introduction of the vinyl group-containing monomer (c) into the fluoropolymer (A) also reduces the crystallinity of the fluoropolymer (A), improves the transparency, and the fluorine-based reactive monomer (B). And effective in improving the compatibility with the non-fluorine-containing monomer (C), and improving the transparency and flexibility of the cured resin obtained by irradiating the resin composition according to the present invention with active energy rays, that is, the sheath material. Is.

The copolymerization ratio of the α, β-ethylenically unsaturated carboxylic acid ester monomer (b) and / or the vinyl group-containing monomer (c) in the fluoropolymer (A) is such that the fluoropolymer (A There is no particular limitation as long as the content of fluorine atoms in) is less than 30% by weight. When the fluorine atom content of the fluoropolymer (A) is less than 30% by weight, poor compatibility with the fluorine-based reactive monomer (B) occurs, and the transparency of the cured resin obtained after irradiation with active energy rays is remarkable. It becomes low and cannot be used as a sheath material for optical transmission fibers.

The molecular weight of the fluorinated polymer (A) is not particularly limited, but with respect to the resin composition according to the present invention,
The number average molecular weight Mn is preferably 1,000 or more for the purpose of imparting a viscosity that can be applied to the optical transmission fiber core wire.

The fluoropolymer (A) is essential for imparting to the resin composition according to the present invention a viscosity that can be applied to the optical transmission fiber core wire, and the fluoropolymer (A) is used. ) Is very difficult to apply, and the optical transmission fiber is also poor.

The fluorine-containing (meth) acrylate (a) has a fluorine atom content of 30% by weight or more and contains an acryloyl group or a methacryloyl group in the molecule, and has the general formula (I).

[0027]

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[In the formula, Rf is a perfluoroalkyl group having 1 to 20 carbon atoms, a partially fluorinated aliphatic group, or those in which an oxygen atom intervenes in the main chain thereof, for example,

[0029]

[Chemical 6]

Etc., R ₁ is H, CH ₃ , Cl, F or --X--Rf, X is a divalent linking group, specifically-(CH ₂ ) _n- ,

[0031]

[Chemical 7]

[0032]

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[0033]

[Chemical 9]

(However, n is an integer of 1 to 10, and R ₂
Is H or an alkyl group having 1 to 6 carbon atoms. ),

[0035]

[Chemical 10]

[0036]

[Chemical 11]

[0037]

[Chemical 12]

[0038]

[Chemical 13]

[0039]

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[0040]

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Etc. ], A compound represented by

[0042]

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Examples of such compounds include compounds having a plurality of perfluoroalkyl groups in the molecule. More specific examples of these include the following.

[0044]

[Chemical 17]

[0045]

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[0046]

[Chemical 19]

[0047]

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As the fluorine-containing (meth) acrylate (a), two or more kinds of compounds having different structures may be used.
It goes without saying that the present invention is not limited to the above specific examples.

Specific examples of the ester monomer (b) of α, β-ethylenically unsaturated carboxylic acid include the general formula R ₅ OOC (R ₃ ) C═C (R ₄ ) COOR ₆ (III) R ₃ and R ₄ are H, F, Cl or CH ₃ ,
R ₃ and R ₄ may be the same or different, and R ₅ and R ₆ are H
Alternatively, it is a group containing an alkyl group having 1 to 20 carbon atoms or a fluorinated alkyl group, and R ₅ and R ₆ may be the same or different, but when either one is H, the other is H.
It is a group other than. ] The compound represented by this is mentioned. When R ₅ and R ₆ are alkyl groups among them, the number of carbon atoms thereof is compatible with the fluorine-containing (meth) acrylate (a), non-crystallizing, and the fluorine-containing reactive monomer (B). From the viewpoint of compatibility and transparency as a resin obtained by curing after irradiation with active energy, that is, a sheath material, 3
-8 are especially preferable.

More specific examples of the ester monomer (b) of α, β-ethylenically unsaturated dicarboxylic acid include the following compounds. b-1 fumaric acid diethyl ester b-2 fumaric acid di-n-butyl ester b-3 fumaric acid di-iso-butyl ester b-4 fumaric acid di-t-butyl ester b-5 fumaric acid dipropyl ester b- 6 Fumaric acid di-2-ethylhexyl ester b-7 Fumaric acid dihexyl ester b-8 Fumaric acid ethyl butyrate b-9 Maleic acid dibutyl ester b-10 Maleic acid dioleyl ester b-11 Fumarate n-butyl, t- Butyl ester b-12 Ethyl fumarate, iso-butyl ester

[0051]

[Chemical 21]

[0052]

[Chemical formula 22]

[0053]

[Chemical formula 23]

Needless to say, the present invention is not limited to these specific examples. The vinyl group-containing monomer (c) is roughly classified into those containing one or more vinyl groups in the molecule, and the form of introducing the vinyl group into the molecule is an acryloyl group or a methacryloyl group. Good.

Specific examples of the vinyl group-containing monomer (c) containing one vinyl group in the molecule include: c-1 styrene c-2 nucleus-substituted methylstyrene c-3 nucleus-substituted methoxystyrene c-4 N-vinyl. Pyrrolidone c-5 N-vinylcaprolactam c-6 acrylonitrile c-7 (meth) acrylic acid c-8 methyl (meth) acrylate c-9 ethyl (meth) acrylate c-10 n-propyl (meth) acrylate c-11 iso -Propyl (meth) acrylate c-12 n-butyl (meth) acrylate c-13 iso-butyl (meth) acrylate c-14 t-butyl (meth) acrylate c-15 hexyl (meth) acrylate c-16 2-ethylhexyl (Meth) acrylate c-17 ethyl carbitol (meth) acry Rate c-18 Methyl triglycol (meth) acrylate c-19 Methyl propylene glycol (meth) acrylate c-20 Methyl dipropylene glycol (meth) acrylate c-21 Methyl tripropylene glycol (meth)
Acrylate c-22 polypropylene glycol mono (meth) acrylate (number average molecular weight 150 to 1000) c-23 stearyl (meth) acrylate c-24 phenoxyethyl (meth) acrylate c-25 ethoxyethyl (meth) acrylate c-26 methoxyethyl (Meth) acrylate c-27 butoxyethyl (meth) acrylate c-28 N, N-diethylaminoethyl (meth) acrylate c-29 N, N-dimethylaminoethyl (meth) acrylate c-30 glycidyl (meth) acrylate c- 31 allyl (meth) acrylate c-32 2-hydroxyethyl (meth) acrylate c-33 2-hydroxymethyl (meth) acrylate c-34 2-methoxyethoxyethyl (meth) acrylate c-3 2-ethoxyethoxy ethyl (meth) c-36 benzyl (meth) acrylate c-37-cyclohexyl (meth) acrylate c-38 dicyclopentenyl (meth) acrylate c-39 dicyclopentenyloxyethyl (meth)
Acrylate c-40 2-Hydroxyethyl (meth) acryloyl phosphate c-41 Tetrahydrofurfuryl (meth) acrylate c-42 Dicyclopentadienyl (meth) acrylate c-43 Dicyclopentadiene ethoxy (meth) acrylate c-44 p -Benzylphenoxyethyl (meth) acrylate c-45 1,6-hexanediol mono (meth) acrylate c-46 neopentyl glycol mono (meth) acrylate c-47 glycerin mono (meth) acrylate c-48 trimethylolpropane mono ( (Meth) acrylate c-49 pentaerythritol mono (meth) acrylate c-50 2-hydroxy-3-phenyloxypropyl (meth) acrylate c-51 2-hydroxy-3-octyl io Shipuropiru (meth) acrylate c-52 diethylene glycol mono (meth) acrylate c-53 polyethylene glycol (400) mono (meth) acrylate c-54-methyl polypropylene glycol mono (meth) acrylate (number average molecular weight 150 to 1000)

[0056]

[Chemical formula 24]

[0057]

[Chemical 25]

A specific example of the vinyl group-containing monomer (c) containing two or more vinyl groups in the molecule is a polyvalent (meth) acrylate in which two or more (meth) acrylic acids are bonded to a polyhydric alcohol. The following compounds may be mentioned as more specific compounds. c-58 ethylene glycol di (meth) acrylate c-59 diethylene glycol di (meth) acrylate c-60 triethylene glycol di (meth) acrylate c-61 polyethylene glycol di (meth) acrylate (number average molecular weight 150 to 1000) c- 62 propylene glycol di (meth) acrylate c-63 dipropylene glycol di (meth) acrylate c-64 tripropylene glycol di (meth) acrylate c-65 polypropylene glycol di (meth) acrylate (number average molecular weight 200 to 1000) c- 66 neopentyl glycol di (meth) acrylate c-67 1,3-butanediol di (meth) acrylate c-68 1,4-butanediol di (meth) acrylate c-69 1,6-he San'njioruji (meth) acrylate c-70-hydroxy Viva phosphoric acid ester neopentyl glycol di (meth) acrylate

[0059]

[Chemical formula 26]

[0060]

[Chemical 27]

C-73 Bisfer A di (meth) acrylate c-74 trimethylolpropane tri (meth) acrylate c-75 pentaerythritol tri (meth) acrylate c-76 dipentaerythritol hexa (meth) acrylate c-77 penta Erythritol tetra (meth) acrylate c-78 Trimethylolpropane di (meth) acrylate c-79 Dipentaerythritol monohydroxypenta (meth) acrylate In addition to the above, as the vinyl group-containing monomer (c), neomer NA-305, neomer BA-601, Neomar T
A-505, Neomer TA-401, Neomer PHA4
05X, Neomar TA705X, Neomar EA400
X, NEOMER EE401X, NEOMER EP405X, NEOMER HB601X, NEOMER HB605X [above, Sanyo Chemical Industry Co., Ltd.], KAYARAD HX-22
0, HX-620, D-310, D-320, D-33
0, DPHA, DPCA-20, DPCA-30, DP
CA-60, DPCA-120 [above, Nippon Kayaku Co., Ltd.
[Made].

According to the knowledge of the present inventors, from the viewpoint of the transparency of the resin after curing, among the above specific examples, the vinyl group-containing monomer (c) has a methyl group in the molecule. Is particularly preferable. Further, as the vinyl group-containing monomer (c), a single compound may be used, or two or more kinds of compounds having different structures may be used.

Needless to say, the present invention is not limited to the above specific examples. The fluorinated polymer (A) according to the present invention is produced by a polymerization method known in the art, for example, radical polymerization, anionic polymerization, cationic polymerization or the like, using heat, light, electron beam, radiation or the like as polymerization initiation energy. However, industrially, radical polymerization using heat and / or light as the polymerization initiation energy is preferable. Any of bulk polymerization, solution polymerization, and emulsion polymerization can be adopted as the polymerization form by these polymerization methods.

When heat is used as the polymerization initiation energy, when a catalyst is used or a polymerization initiator such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide-cobalt naphthenate, or light such as ultraviolet rays is used. In addition, a so-called photopolymerization initiator known in the art (for example, compounds shown in E-1 to 11 described below) is included.
Then, if necessary, a photosensitizer such as an amine compound or a phosphorus compound can be added to further accelerate the polymerization.

In these radical polymerizations, a chain transfer agent such as lauryl mercaptan, octyl thioglycolate, C ₃ F ₁₇ CH ₂ CH ₂ SH, etc. may be used in combination, if necessary, to give a fluorine-containing polymer (A). The degree of polymerization can be adjusted.

In the case of polymerizing and curing with an electron beam or radiation, it is not necessary to add a polymerization initiator or the like. When the fluoropolymer (A) is obtained by solution polymerization, the solvent is not limited as long as it does not adversely affect the polymerization reaction.

The fluorine-based reactive monomer (B) according to the present invention can be polymerized in the presence or absence of a photopolymerization initiator, and has a fluorine-containing (meta) structure represented by the general formula (I). ) An acrylate and / or a fluorine-containing (meth) acrylate represented by the general formula (II). Of these, considering the dilutability of the fluoropolymer (A) and the transparency of the resin after curing, in the compound of the general formula (I), Rf has 1 to 12 carbon atoms,
The divalent linking group is _{-CH 2 -, - CH 2 CH} 2 -,

[0068]

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[0069]

[Chemical 29]

[0070]

Embedded image

[0071]

[Chemical 31]

[0072]

Embedded image

[0073]

[Chemical 33]

And the like are preferable. Furthermore, the general formula (II)

[0075]

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[Wherein x is an integer of 1 to 2 and y is 4 to 12]
, R ₇ represents H, CH ₃ , Cl or F. ] The compound represented by the above can also be used as the fluorine-based reactive monomer (B). Specific examples of these include the following.

[0077]

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[0078]

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The fluorine-based reactive monomer (B) does not necessarily have to be a single compound, and may be a mixture of two or more kinds of compounds having different structures. The proportion of the fluorine-based reactive monomer in the resin composition of the present invention is preferably 10% by weight or more from the viewpoint of the transparency of the resin after curing.
If it is less than 10% by weight, transmission loss due to turbidity of the resin occurs.

The non-fluorine-based monomer (C) is used for the purpose of imparting transparency, flexibility, toughness and the like after curing of the active energy ray-curable composition according to the present invention, and refraction of the resin after curing. It is extremely important for the purpose of adjusting the refractive index, and the proportion in the resin composition according to the present invention is not particularly limited, but 50% by weight or less is preferable for the purpose of controlling the refractive index to 1.44 or less.

Examples of the non-fluorine-containing monomer (C) include the same as the vinyl group-containing monomer (c). However, from the viewpoint of imparting transparency, flexibility, and toughness to the resin after curing, and the compatibility with the fluorine-based reactive monomer (B), the inventors of the present invention have found that 1 in the molecule. It is more preferable to have one or more methyl groups and to contain one or more methacryloyl groups or acryloyl groups.

Typical typical examples of these are: c-10, 11, 12, 13, 14, 17, 19,
20, 21, 22, 26, 27, 34, 35, 46, 4
8, 54, 55, 56, 57, 62, 63, 64, 6
5, 66, 67, 70, 71, 72, 74, 78 etc.,
Neomer NA-305, TA505, PHA405X,
TA705X, EP405X, HB605X [above-mentioned Sanyo Chemical Industry Co., Ltd. make] etc.

The non-fluorine-containing monomer (C) does not necessarily have to be a single compound, and may be a mixture of two or more compounds having different structures. Further, it goes without saying that the present invention is not limited to the above specific examples.

Examples of the additive (D) according to the present invention include a solvent for adjusting viscosity, a light resistance stabilizer, a coupling agent and other additives for improving adhesion to the optical transmission fiber core wire, and core wire. As the defoaming agent, the leveling agent, and the surfactant for uniform application, fluorine-based ones are preferable.

In addition to the above-mentioned additives (D),
Non-polymerizable fluorine compound, for example, HO- (CH _{2) r} -C
_S F _{2S +} 1 (r is an integer from 1 to 4, s is an integer from 1 to 20.) Such as fluorinated alcohol, HOOC-
Fluorinated carboxylic acid such as (CH ₂ ) _t -C _u F _{2u + 1} (t is 0 or an integer of 1 to 4 and u is an integer of 1 to 20), commonly called a fluorine oil. Fluorinated polyether, N (C ₄ H ₈ ) ₃ , perfluorodecalin, C ₈
Compounds commonly referred to as fluorine-based inert liquids such as F ₁₇ OC ₄ F ₉ and C ₉ F ₂₀ can be used. The proportion of the non-polymerizable fluorine compound additive in the active energy ray-curable resin composition is preferably 30% by weight or less, and 20% by weight or less, because the strength of the resin after curing decreases if added excessively. More preferable.

The active energy ray-curable resin composition according to the present invention is prepared by applying or impregnating a base material or the like to an optical transmission fiber core wire, and then irradiating the active energy ray such as light, electron beam or radiation. It can be polymerized and cured to form a desired coating film such as a sheath material. In some cases, heat can also be used as an energy source.

When light such as ultraviolet rays is used as the active energy source, a photopolymerization initiator (E) known in the art, for example, E-1: benzophenone, E-2: acetophenone, E-3: benzoin, E -4: Benzoin ethyl ether, E-5: Benzoin isobutyl ether, E-
6: benzylmethyl ketal, E-7: azobisisobutyronitrile, E-8: 1-hydroxycyclohexyl phenyl ketone, E-9: 2-hydroxy-2-methyl-1-phenylpropan-1-one, E-10: 1- (4'-Isopropylphenyl) -2-hydroxy-2
-Methylpropan-1-one, E-11: 1 (4'dodecyl-phenyl) -2-hydroxy-2-methylpropan-1-one and the like are preferably used as a catalyst.

If necessary, a photosensitizer such as an amine compound or a phosphorus compound can be added to accelerate the polymerization. The preferable ratio of the photopolymerization initiator in the active energy ray-curable resin composition according to the present invention is 0.0
It is 1 to 10% by weight, more preferably 0.1 to 7% by weight. When polymerizing and curing with an electron beam or radiation, it is not necessary to add a polymerization initiator.

As described above, the solvent can be added in order to control the viscosity, coatability and film thickness of the coating composition of the present invention. Such a solvent is not limited as long as it does not adversely affect the polymerization reactivity of the composition of the present invention, but is not limited to alcohols such as methanol, ethanol and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and acetic acid. Methyl, ethyl acetate, butyl acetate, etc. ester type, chloroform, dichloroethane, carbon tetrachloride, etc. chlorine type, benzotrifluoride, chlorobenzotrifluoride, m-xylene hexafluoride, tetrachlorodifluoroethane, 1 ，
1,2-trichloro-1,2,2-trifluoroethane,
A low boiling point solvent such as trichloromonofluoromethane is preferable from the viewpoint of workability.

When the active energy ray-curable resin composition of the present invention is applied to or impregnated into a substrate as a solution prepared by dissolving it in a solvent, it is heated at room temperature, or if necessary, heated or decompressed before the initiation of polymerization and curing. Therefore, a step of removing the solvent is required. When the solvent is removed by heating, it is preferable to carry out the heating at a temperature of 80 ° C. or lower so as not to cause the polymerization of the monomer or the like by heating.

The energy ray-curable resin composition according to the present invention can be applied to a substrate by various methods known in the art, such as brush coating, applicator, bar coater, roller brush, roll coater and the like. A coating method, a spray coating method using an air spray or an airless spray coating machine, a flow coating method using a shower coater or a curtain flow coater (flow coating), a dipping method, a casting method, and a spinner coating method can be used. It is desirable to properly use the base material in accordance with the material, shape, application, etc.

As a method of applying the energy ray-curable resin composition according to the present invention to the core wire of an optical transmission fiber and curing it, the optical transmission fiber core wire is continuously immersed in a storage tank containing the resin composition of the present invention. By pulling, removing the solvent if necessary, a method of irradiating with an active energy ray to cure and form the sheath portion, or continuously applying the resin composition of the present invention through a light-transmitting fiber core wire to a die capable of continuously supplying the resin composition. , DT 2,45, such as a method of irradiating with active energy rays to cure and form the sheath portion after removing the solvent as necessary.
Methods known in the art such as those shown in JP-A No. 9,320 and JP-A No. 53-139545 can be used.

When the resin composition of the present invention is polymerized and cured by irradiation with energy rays, sterilizing lamps, fluorescent lamps for ultraviolet rays, carbon arc, xenon lamps, high-pressure mercury lamps for copying, medium-pressure or high-pressure mercury lamps and A high-pressure mercury lamp, an electrodeless lamp, a metal halide lamp, ultraviolet rays using natural light as a light ray, or an electron beam from a scanning type or curtain type electron beam accelerating path can be used. In this case, it is preferable to irradiate in an atmosphere of an inert gas such as nitrogen gas from the viewpoint of efficient polymerization.

Examples of the optical fiber core wire according to the present invention include quartz type and plastic type such as polymethylmethacrylate, deuterated polymethylmethacrylate, polyethylmethacrylate, polystyrene and polycarbonate.

In the formation of the sheath component of the optical transmission fiber of the present invention, when a conventional heat-curable silicone resin or a hot melt of a fluoropolymer as described above is used, it is caused by shrinkage of the sheath component after curing. In some cases, micro-pending occurs in the optical transmission fiber, resulting in significant transmission loss.

However, according to the method for producing an optical transmission fiber of the present invention, there is no problem as described above,
There are economic advantages such as improvement of the quality and yield of the optical transmission fiber. Further, the drawing speed of the optical transmission fiber is 3 to 6 m / sec, and there is an advantage in terms of production that the manufacturing speed of the optical transmission fiber is 3 to 5 times faster than the conventional one. Furthermore, the optical transmission fiber of the present invention is remarkably excellent in the adhesion between the core portion and the sheath portion as compared with the conventional fiber, and therefore has an advantage that it can withstand use conditions involving severe vibration and bending. .

In the resin composition of the present invention, a resin having a refractive index suitable for the purpose can be easily obtained by adjusting the ratio of each constituent as described above, and the refractive index is 1.3.
Since a transparent resin of about 3 can be obtained, it is possible to increase the numerical aperture and the diameter of the optical transmission fiber.

Next, specific synthesis examples and examples of the present invention will be described, but it goes without saying that the present invention is not limited to these examples. "Part" in the sentence,
“%” Is based on weight.

The performance of the cured resin obtained by irradiation with active energy rays was then evaluated by the method. Evaluation of Adhesiveness Polymethylmethacrylate plate [Acrylite (trade name)-# 001, plate thickness 2 mm, manufactured by Mitsubishi Rayon Co., Ltd.], polystyrene plate [Styron (trade name) plate thickness 2 mm, Dow Chemical Company] and glass plate (plate thickness 5 mm) ) Has a cured film thickness of 10
The active energy ray-curable resin according to the present invention was applied so as to have a thickness of 0 μm.

As the active energy ray source, a two-lamp condensing type high-pressure mercury lamp (160 W / cm) was used and cured at a conveyor speed of 200 m / min. In the case of the comparative hot-melt type fluorine-containing resin, a film having a thickness of 100 μm was obtained from a heat press at 200 ° C. for 5 minutes at a pressure of 100 kg / cm ² .
Lay this on each substrate surface, 230 ℃ for 10 seconds, 5kg / c
It was laminated by pressure bonding under the condition of m ² .

The adhesion test of the thus obtained sample was evaluated according to the evaluation standard according to JIS5400.

[0102]

[Table 1]

Evaluation of optical transmission performance The optical transmission performance of the optical transmission fiber is the same as that of the device shown in FIG.
/ Km) was measured and evaluated. The measurement conditions are as follows.

Interference filter (main wavelength) 650 μm Total length of optical transmission fiber 5 m Cutting length of optical transmission fiber 4 m Bobbin diameter 190 mm Mandrel test To evaluate the adhesion and toughness of the sheath material to the optical transmission fiber core wire, the diameter of 5 mm The optical transmission fiber was wound around the mandrel and enlarged with a microscope, and the adhesion between the optical transmission fiber core wire and the sheath material and the presence or absence of cracks in the sheath material portion were observed, and evaluated according to the following three grades.

Evaluation point 3: No change in adhesion between the core portion and the sheath portion and no occurrence of cracks or the like in the sheath portion. 2: A change in adhesion between the core portion and the sheath portion and / or a slight occurrence of cracks or the like in the sheath portion is recognized.

1: Separation between the core portion and the sheath portion and / or occurrence of cracks in the sheath portion are recognized. Hereinafter, all the abbreviations of the compounds indicate the aforementioned compounds. Further, Ac after the abbreviation is an acrylate compound, Ma
c indicates a methacrylate compound.

Synthesis Example 1 Synthesis of a-1 / b-2 / c-12 (Ac) copolymer 90/5/5 (%) 500 ml equipped with cooling condenser, thermometer and stirrer
In a 4-neck round bottom flask, 180 g of a-1 and b-1 1
0 g, 10 g of c-12, and 1 g of azobisisobutyronitrile (hereinafter referred to as AIBN) were weighed and stirred under N ₂ gas atmosphere at 70 ° C. for 30 minutes. Further 120
After stirring at 0 ° C. for 5 minutes, the viscous massive polymer was taken out of the system when heated.

The molecular weight calculated from GPC was Mn = 920,000 in terms of styrene. Fluorine atom content is 56.1%
Met. The polymer was transparent under an atmosphere of 25 ° C., and the refractive index nD ²⁵ was 1.368.

Synthesis Example 2 to Synthesis Example 9 The molecular weight and refractive index of the fluoropolymer synthesized in the same manner as in Synthesis Example 1 are summarized in Table 2 below.

[0110]

[Table 2]

Synthesis Example 10 Synthesis of a-3 / b-17 / c-14 (Mac) copolymer 80/10/10 (%) 500 ml equipped with cooling condenser, thermometer and stirrer
In a four-necked round bottom flask, a-3 80 g, b-17
10g, c-14 (Mac) 10g, and lauryl mercaptan 1 g, AIBN0.3G, was weighed 1,1,1-trichloroethane 230 g, N ₂ gas atmosphere, 8
The reaction was carried out at 0 ° C for 10 hours. The solvent was distilled off under reduced pressure to obtain the desired polymer. Mn = 11 Man, nD ²⁵ = 1.37
It was one.

Synthetic Examples 11 and 12 Table 3 shows the molecular weight and refractive index of the fluoropolymers synthesized in the same manner as in Synthetic Example 10.

[0113]

[Table 3]

Synthesis Example 13 Synthesis of a-1 / c-46 (Mac) copolymer 95/5 (%) In a 500 ml glass cylindrical flask equipped with a stirrer,
a-1 380 g, c-46 (Mac) 20 g, thioglycolic acid octyl 2 g, and E-9 12 g as a photopolymerization initiator were weighed, and while being stirred at 60 ° C., an ultraviolet fluorescent lamp 60 W2 was installed on the side. And then reacted for 1 hour. By this operation, a viscous polymer of 200 ps was obtained at 80 ° C. Since it is a crosslinked polymer, its molecular weight could not be measured by GPC. The fluorine content was 59.2%. By gas chromatography, 24% of the total amount of unreacted monomer remained. The refractive index nD ²⁵ was 1.352.

Comparative Synthesis Example 1 In the same manner as in Synthesis Example 1, a-1 / b-2 / c-12 (A
c) Copolymerization was performed at a composition of 40/30/30 (%). The resulting polymer had a fluorine atom content of 24.9%, a styrene-equivalent molecular weight Mn of 910,000, and a refractive index n.
D ²⁵ was 1.451.

Production Examples 1 to 13 and Comparative Production Examples 1 to 4 (Production of Active Energy Ray-Curable Resin Composition) Fluorine-containing polymers (A) and fluorine obtained in Synthesis Examples 1 to 13 and Comparative Synthesis Example 1 System reactive monomer (B), non-fluorine monomer (C), additive (D), and photopolymerization initiator (E) are used, and active energy ray-curable resin is blended in Table 4, Table 5 and Table 6. A composition was prepared.

Examples 1 to 13 and Comparative Examples 1 to 7 The adhesiveness of this resin composition to polymethylmethacrylate plates, polystyrene plates, and glass plates, and various properties when used as a sheath material for optical transmission fibers are shown. Table 7, Table 8,
The results are summarized in Tables 9 and 10.

When the active energy ray-curable resin composition is used, the optical transmission fiber core wire is continuously dipped in the bath of the resin composition and pulled up to obtain 160 W / cm at a drawing speed of 300 m / min. Ultraviolet rays were irradiated from three high pressure mercury lamp condensing type lamps to form an optical transmission fiber.

The optical transmission fibers shown in Comparative Examples 5 and 6 were formed by applying a fluoropolymer melted at the temperature shown in the table to the optical transmission fiber core wire and air-cooling.

The silicone resin shown in Comparative Example 7 was cured at 150 ° C. for 1 minute. In this case, the drawing speed of the optical transmission fiber is 3 m / min. In the optical transmission fiber containing polymethylmethacrylate and polystyrene as core components, the core wire diameter was 500 μm, and the sheath component thickness was 40 μm. Further, in the optical transmission fiber having quartz as the core component, the diameter of the core wire was 250 μm, and the thickness of the sheath portion was 30 μm.

In Tables 7 to 10, PM and PS are optical transmission fibers having polymethylmethacrylate and polystyrene as cores, respectively, and G is an optical transmission fiber having quartz as cores.

[0122]

[Table 4]

[0123]

[Table 5]

[0124]

[Table 6]

[0125]

[Table 7]

[0126]

[Table 8]

[Table 9]

[Table 10]

As is apparent from Tables 7 to 10, the optical transmission fiber using the active energy ray-curable resin according to the present invention as a sheath material has a significantly superior optical transmission property to the conventional one. .

Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 5/101 C08K 5/101 C08L 33/16 LHW C08L 33/16 LHW G02B 6/00 386 G02B 6/00 386 391 391

Claims (1)

(57) [Claims] 1. The following general formula (I) having a fluorine atom content of 30% by weight or more: [In the formula, Rf is a perfluoroalkyl group having 1 to 20 carbon atoms, a partially fluorinated aliphatic group or an intervening oxygen atom in the main chain thereof, and R ₁ is H, CH ₃ , Cl, F
Alternatively, it is -X-Rf, and X represents a divalent linking group. ] The polymer of the fluorine-containing (meth) acrylate (a) represented by or the ester monomer (b) and / or vinyl group of this fluorine-containing (meth) acrylate (a) and α, β-ethylenically unsaturated dicarboxylic acid A copolymer with the containing monomer (c), the fluorine-containing (meth) acrylate (a) represented by the above general formula (I) and / or the following general formula (II): [In the formula, x is an integer of 1 to 2, y is an integer of 4 to 12, R ₇
Represents H, CH ₃ , Cl or F. ] The fluorine-containing (meth) acrylate (d) represented by these, The optical transmission fiber which uses the active energy ray curable resin composition which gives a hardened | cured material whose refractive index is 1.44 or less as a sheath component.