JPH04108637A - Coated optical fiber - Google Patents

Abstract

PURPOSE:To improve heat resistance by coating the outside of an optical fiber with a specified energy ray-curing resin. CONSTITUTION:An energy ray-curing resin of 1000-1000000mol.wt. having 1000-10000cPs viscosity (at 25 deg.C) is prepared by compounding 10-90 pts.wt. of (meth)acryl oligomer and 90-10 pts.wt. of reactive diluent having F and cyano groups expressed by formula I or II (wherein (l), (m) and (n) are 1-10) with total 100 pts.wt., and 1-10 pts.wt. polymn. initiator (e.g. benzoin). The (meth)acryl oligomer is obtained by the reaction of polyol component (e.g. polyoxytetramethylene glycol), isocyanate component (e.g. tolylene diisocyanate) and acrylate component (e.g. 2-hydroxyethyl (meth)acrylate). Then, this resin is applied on the outside of an optical fiber 1 and cured by irradiation of energy ray to form a coating layer 2. Thus, the coated optical fiber 3 is obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a coated optical fiber in which a coating of an energy ray-curable resin that is cured by irradiation with energy rays such as ultraviolet rays is formed on the outer periphery of the optical fiber. It is about improvement.

[Conventional technology]

In optical fibers used for optical communications, it is desirable to apply a plastic coating to the outer periphery of any optical fiber, whether it is an optical glass fiber or a silica-based glass fiber, immediately after being made into a fiber. This is to prevent the strength of the fiber from deteriorating due to scratches on the surface of the fiber that occur when the fiber is made into a fiber or cracks that grow when the bare fiber is exposed to air. Such a plastic layer is generally made of thermosetting silicone resin or ultraviolet curable resin (hereinafter also abbreviated as rUV resin).
Energy ray curable resins such as radiation curable resins and the like are used, and the demand for UV resin-coated fibers has particularly increased in recent years.

[Problem to be solved by the invention]

Examples of the UV resin used in the UV resin-coated fiber include epoxy acrylate, urethane acrylate, and polyester acrylate. However, the UV resin currently used as an optical fiber coating material has a problem in that it cannot be said to be excellent in heat resistance.

Therefore, in areas where there is no risk of exposure to high temperatures, UV
Even if resin-coated optical fibers could be used, they could not be used in cases where this risk existed.

An object of the present invention is to provide a coated optical fiber that solves the problem of heat resistance and can be installed even in places where it may be exposed to high temperatures.

[Means to solve the problem]

As a result of efforts in research and development to achieve the above object, the present inventors discovered that heat resistance can be greatly improved by incorporating fluorine atoms and cyano groups into the coating resin layer, and have thus arrived at the present invention. did it.

That is, the present invention provides a coated optical fiber having a coating made of an energy ray curable resin on the outer periphery of the optical fiber, wherein the energy ray curable resin contains a (meth)acrylic oligomer, a reactive diluent, and a polymerization initiator. A coated optical fiber is provided which is polymerized as a basic component and wherein the reactive diluent contains a fluorine atom and a cyano group.

[Effect]

The energy ray-curable resin used for the coating of the present invention has a (meth)acrylic oligomer, a reactive diluent, and a polymerization initiator as essential components, and the reactive diluent has a fluorine atom and an ano group. The resin has a molecular weight of 1.000 to 1.000.00.
0.

Since the coated optical fiber of the present invention contains fluorine atoms and cyano groups derived from the reactive diluent in the coating resin layer, the heat resistance of the coating layer can be improved compared to conventional products. The reason for this is that the carbon-fluorine bond energy is large, and the cyano group undergoes a cycloaddition reaction by heat treatment to form a 6N ring, resulting in a rigid structure.

Examples of the reactive diluent compound containing a fluorine atom and a cyano group of the present invention include the following general formulas (I), (I
Those shown in I) can be mentioned.

General formula (1) % formula %) General formula (n) CF,=CF(OCF, CF(CF, ))nOCF2C
F(C)l)CF.

However, in general formula (1), (I[), 1. m.

n represents a repeating unit, and each represents an integer of 1 to 10.

Particularly preferred compounds of the above general formulas (I) and (II) include the following compounds (1) to (2).

Compound■ CF3 CFz=CFOCFzCFOCFtCN compound■ CF3 CFz”CFOCFtCFOCFtCFtCN compound■ C.F.

CFz''CFOCFzCFOCFzCFCFsN It is also possible to use a combination of a reactive diluent containing a fluorine atom and a reactive diluent containing a cyano group.

The (meth)acrylic oligomer in the present invention consists of a polyol component, an isocyanate component, and an acrylate component. Examples of the polyol component include polyether polyols such as polyoxytetramethylene glycol, polypropylene glycol, and polyethylene glycol, polyolefin glycols, polyester polyols, and polycarbonates. Examples include polyol, polycaprolactone polyol, and the like.

In addition, the isocyanate component of the (meth)acrylic oligomer includes tolylene diisocyanate, diphenylmethane diisocyanate, p-phenylene diisocyanate,
Examples include hexamethylene diisocyanate, xylylene diisocyanate, inphorone diisocyanate, and the like.

As the acrylate component, those having a hydroxyalkyl group having about 2 to 4 carbon atoms, such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate, are used.

Further, in addition to the above-described reactive diluent containing a fluorine atom and a cyano group of the present invention, it is also possible to use the following diluent.

・2-ethylhexynyl (meth)acrylate ・(meth)acrylate of tetrahydrofurfuryl alcohol caprolactone adduct ・(meth)acrylate of nonylphenol ethylene oxide adduct ・Polyethylene glycol di(meth)acrylate ・Polypropylene glycol di(meth)acrylate ・Bisphenol Diethylene glycol di(meth)acrylate, hydrogenated bisphenol triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, epoxy(meth)acrylate synthesized from bisphenol diglycidyl ether, etc. Mono- or poly (meth)acrylates, allyl esters such as diallyl adipate, diallyl phthalate, triallyl trimellitate, triallyl isocyanurate, styrene, vinyl compounds such as vinyl acetate, etc. The polymerization initiator of the present invention includes a resin composition. Preferably, the material can be cured quickly by irradiation with energy rays.
Especially as an initiator for UV-curable paints.

Those used as sensitizers are suitable, such as: benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-methylbenzoin, benzophenone, Michler's ketone, benzyl, benzyl dimethyl ketal, benzyl Diethyl ketal, anthraquinone, methylanthraquinone, 2,2-jethoxyacetophenone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, anthracene, 1,1-dichloroacetophenone, methylorthobenzoylbenzoate, etc. Also, these polymerization initiation Examples include those in which the agent is used in combination with a small amount of sensitizing aid such as amines.

The content of the (meth)acrylic oligomer in the energy ray-curable resin of the present invention is preferably 10 parts by weight or more and less than 90 parts by weight, and the reason why it is limited to this range is the necessity of adjusting the viscosity during coating. It also depends on the content of the reactive diluent.

It is particularly preferable that the reactive diluent containing a fluorine atom and a cyano group in the present invention is contained in the energy ray curable resin in a proportion of 10 parts by weight or more and less than 90 parts by weight. If it is less than 10 parts by weight, it will not be effective in improving heat resistance (
This is inconvenient, and if it exceeds 90 parts by weight, it is not preferable because the coating properties for optical fibers deteriorate.

In the present invention, the amount of the above polymerization initiator added is (meth)
Usually about 1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the total amount of acrylic oligomer and reactive diluent.
Parts by weight. If this amount is too small, the curability cannot be satisfied, and even if it exceeds a predetermined amount, no further improvement in the curing rate can be expected.

The energy ray curable resin of the present invention has the above-mentioned (meth)acrylic oligomer, a reactive diluent containing a fluorine atom and a cyano group, and a polymerization initiator as essential components, and optionally acrylic resin, polyamide resin, Approximately 10 parts by weight of various modification resins such as polyether resin, polyurethane resin, polyamideimide resin, silicone resin, and phenol resin, and various additives such as organosilicon compounds, surfactants, and sensitizers are blended. From the viewpoint of workability, it is desirable that the overall viscosity is usually adjusted to a range of 1,000 to 10,000 centivoise (25° C.).

The coated optical fiber of the present invention may be manufactured by a conventionally known resin coating forming method of this type. For example, an energy beam curing type in which an optical fiber base material is sent into a drawing furnace, heated and melted, and drawn into an optical fiber (glass fiber), and then a reactive diluent and a polymerization initiator are added as described above using a coating device. After applying the resin, the applied layer is cured by irradiating the resin with energy rays to form a coated optical fiber, which is then wound up while being taken off. Examples of curing means include means such as using an ultraviolet curing device using a metal halide lamp when irradiating ultraviolet rays as energy rays. Regarding the curing conditions, etc., the Young's modulus, gel fraction, etc. of the resin are measured, and the material and composition of the optical fiber are not particularly limited.

〔Example〕

Hereinafter, the structure and effects of the present invention will be explained in more detail by giving specific examples and comparative examples of the present invention.

Examples 1 to 3 and Comparative Examples 1 to 3 1 mole of polyoxyditetramethylene glycol with an average molecular weight of 2000 and 2 moles of tolylene diisocyanate were charged into a 51 four-bottle flask equipped with a stirrer, a condenser, and a thermometer. The reaction was carried out at ~70°C for 2 hours. Then 2-
Adding 2 moles of hydroxyethyl acrylate, 2270 cl of isocyanate group was determined by infrared absorption spectrum.
The reaction was continued until the characteristic absorption band ' disappeared.

70 parts of the urethane acrylate oligomer thus obtained (hereinafter, parts by weight are expressed unless otherwise specified)
30 parts of the above compound 1 as a reactive diluent and 3 parts of benzoin methyl ether as a polymerization initiator were added to
An energy ray-curable resin was obtained. This energy ray curing resin is applied around the optical fiber 1 having the structure shown in Fig. 1, and is irradiated and cured using two metal halide lamps with a length of 50 effl to form a coating layer 2, thereby forming a coated optical fiber. 3 (product of the present invention) was manufactured. After heat-treating the coated optical fiber obtained above at 100°C for 3 hours,
Although it was left in an air atmosphere at 200° C. and observed for 3 days, no cracks in the coating were found (Example 1).

Various coated optical fibers were manufactured in the same manner as in Example 1 except that the type of reactive diluent was changed to the compound shown in Table 1 (Examples 2 and 3 and Comparative Examples 1 to 3).
. These were also observed for cracks in the coating.

Table 1 below shows the oligomers, reactive diluents, and polymerization initiators used in each of the Examples and Comparative Examples above, as well as the presence or absence of cracks in the coatings after being left at 200° C. for 3 days.

From the results of the above Examples and Comparative Examples, it can be seen that the fibers of the coated resin layer of the present invention have excellent heat resistance, and that the fibers in the limited range of the present invention are effective.

〔Effect of the invention〕

As explained above, since the coated optical fiber of the present invention contains fluorine atoms and cyano groups in the coating layer, it is possible to provide a coated optical fiber with excellent heat resistance. Therefore, the coated optical fiber of the present invention, as well as the cable using the same, can be installed and used in a high temperature atmosphere.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a coated optical fiber of the present invention, where 1 represents an optical fiber, 2 represents an energy beam-curable resin coating layer, and 3 represents a coated optical fiber.

Claims (1)

[Claims] (1) In a coated optical fiber having a coating made of an energy ray curable resin on the outer periphery of the optical fiber, the energy ray curable resin contains (meth)acrylic oligomer, a reactive diluent, and a polymerization initiator as basic components. 1. A coated optical fiber characterized in that the coated optical fiber is polymerized as a polymer, and the reaction inhibiting diluent contains a fluorine atom and a cyano group.