JPH0222611A - coated optical fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Public Expenses for Industrial Use> The present invention relates to a coated optical fiber in which a coating layer cured by energy rays such as ultraviolet rays is formed on the outer periphery of the optical fiber.

<Prior Art> In optical fibers used for optical communications, it is considered preferable to immediately apply a plastic coating to the outer periphery of any optical fiber, not only optical glass fiber or quartz-based glass fiber, 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 the air. In addition to thermosetting silicone resins, energy ray curable resins such as ultraviolet ray curable resins (hereinafter referred to as rUV resins) and radiation curable resins are generally used for such plastic layers. The demand for UV@fat-coated optical fibers is increasing.

Such a UV resin-coated optical fiber is manufactured by, for example, continuously applying UV resin using a coating die to an optical fiber that has been drawn in a drawing furnace, and then curing the applied UV resin by irradiating it with ultraviolet rays. Ru. Furthermore, such UV resin-coated optical fibers are further coated with a secondary coating either singly or in combination to form optical fiber cores.

Here, as the UV resin used for the above-mentioned primary coating, for example, epoxy acrylate, urethane acrylate, polyester acrylate, etc. are used, and these resins have excellent adhesion to the optical fiber by being cured by ultraviolet irradiation. Forms a good coating of 9 layers.

However, when connecting optical fiber core wires using such conventional coated optical fibers, the coating layer must be removed using a wire stripper, etc., but the outer peripheral surface of the optical fiber and the primary coating layer must be removed. Since the adhesion with Aro UV resin is too high, there is a problem in that a great deal of force is required to remove the coating. In particular, considerable force is required when removing the coating of a 5-core ribbon core formed by arranging, for example, 5 coated optical fibers in a horizontal direction.

Conventionally, in order to reduce the pull-out force of this coating layer, a mixture of UV411 oil and an additive such as silicone oil is applied to the optical fiber and cured with ultraviolet light to form a coated optical fiber. Methods are being considered.

<Problems to be Solved by the Invention> However, when conventional UV resins are mixed with additives such as silicone oil, the curing speed decreases, so a large amount of ultraviolet irradiation is required to cure the UV resins. For example, there is a problem in that the linear velocity of the optical fiber passing through the curing device must be reduced.

Furthermore, there is a problem in that the resulting cured coating layer changes over time, and silicone oil may precipitate at the interface between the optical fiber and the coating material or on the coating surface, resulting in damage to the appearance and shape.

In view of the above-mentioned circumstances, an object of the present invention is to provide a coated optical fiber in which the coating layer formed on the optical fiber can be easily removed without reducing the coating curing speed. shall be.

<Means for Solving the Problems> The coated optical fiber according to the present invention that achieves the above object has the following features:
Apply energy ray-curable resin to the outer circumference of the optical fiber,
In a coated optical fiber formed by applying a coating layer by curing by irradiation with energy rays, an acrylic or methacrylic oligomer consisting of an acrylate or methacrylate component, an isocyanate component, and a polyol component;
The present invention is characterized in that it uses an energy ray-curable resin that contains a reactive diluent and a polymerization initiator, and in which the isocyanate component is a fluorine-containing diisocyanate.

As mentioned above, the energy ray-curable resin used in the present invention has an acrylic or methacrylic oligomer, a reactive diluent, and a polymerization initiator as essential components, and if necessary, an acrylic resin, polyamide resin,
It is a compound of various modifying resins such as polyether resin, polyurethane resin, polyamideimide resin, silicone resin, and phenol resin, as well as various additives such as organosilicon compounds and surfactants. From the viewpoint of workability, the viscosity of is usually 100 at 25°C.
It is preferable to adjust it within the range of 0 to 10,000 centipoise.

In addition, the acrylic or methacrylic oligomer used in the present invention (hereinafter, acrylic or methacrylic oligomer is referred to as (meth)acrylic oligomer) is an acrylate or methacrylate component (hereinafter, acrylate or methacrylate is referred to as (meth)acrylate). , an isocyanate component and a polyol component, and a fluorine-containing diisocyanate containing a fluorine atom in the molecule is used as the isocyanate component.

Since such a (meth)acrylic oligomer contains a fluorine-containing diisocyanate as an isocyanate component, it can reduce the surface energy of the resin after curing and reduce the pulling force of the coating layer. Furthermore, since the (meth)acrylic oligomer has polymerizable carbon-carbon double bonds at both ends of the molecule, there is no risk of chemical bonding with other resin components and precipitation during the curing reaction.

Here, the fluorine-containing diisocyanate includes 2,2,
3.3-Tetrafluorotetramethylene diisocyanate, 2.2.3.3.4.4.5.5-octafluorohexamethylene diisocyanate, 3, 3.4.4.5
．． 5.6.8.7.7.8.8-Dodecafluorooctamethylene diisocyanate, oxydi(2,2,3,3
-tetrafluoropropane isocyanate).

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

As the polyol component, polyether polyols such as polyoxytetramethylene glycol, polypropylene glycol, and polyethylene glycol, polyolefin glycols, polyester polyols, polycarbonate polyols, and polycaprolactone polyols may be used.

Furthermore, the following can be mentioned as the reactive diluent used in the present invention.

2-Ethylhexyl (meth)acrylate, tetra-drofurfuryl alcohol caprolactone adduct (meth)acrylate, nonylphenol ethylene oxide adduct (meth)acrylate, polyprolene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate ) acrylate, bisphenol diethylene glycol di(meth)acrylate, hydrogenated bisphenol triethylene glycol di(meth)acrylate
Mono- or poly(meth)acrylates such as acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and epoxy(meth)acrylate synthesized from bisphenol diglycidyl ether.

It is also possible to use the following vinyl compounds as the reactive diluent.

diallyl adipate, diallyl phthalate, triallyl trimellitate, Allyl esters such as triallyl isocyanurate, styrene, vinyl acetate, N-vinylpyrrolidone, N, N-dimethylacrylamide, N,N-dimethylaminopropylacrylamide, N,N-dimethylaminoethyl acrylate.

The polymerization initiator used in the present invention is preferably one that can quickly cure the resin composition by irradiation with energy rays, and in particular, those used as initiators and sensitizers for conventional ultraviolet curable paints are suitable. ing. Some examples are shown below.

benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-methylbenzoin, benzophenone, michler's ketone, benzil, benzyl dimethyl ketal, benzyl diethyl ketal, anthraquinone, methylanthraquinone, 2.2-jethoxyacetophenone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, anthracene, 1.1-dichloroacetophenone, Methyl orthobenzoyl benzoate.

Furthermore, as the polymerization initiator, a small amount of sensitizing aid such as amines can be used together with these initiators.

The amount of polymerization initiator added is usually 1 part by weight per 100 parts by weight of the (meth)acrylic oligomer and reactive diluent.
About 10 parts by weight, preferably 1 to 5 parts by weight may be used.

If the amount of this polymerization initiator is too small, it will be difficult to satisfy the curability, while if it exceeds a predetermined amount, no further improvement in the curing rate can be expected.

Examples> Preferred examples of the present invention and comparative examples for comparison will be described below.

Example 1 1 mole of polyoxytetramethylene glycol having an average molecular weight of 1000 and 2 moles of 2,2.3.3-tetrafluorotetramethylene diisocyanate were charged into a 31-piece four-bottle flask equipped with a stirrer, a condenser, and a thermometer. 60～
The reaction was carried out at 70°C for 2 hours. Then, 2 moles of 2- and droxyethyl acrylate were added, and the reaction was continued until the characteristic absorption band of the isocyanate group at 2270 cm' disappeared according to an infrared absorption spectrum.

60 parts of the urethane acrylate oligomer thus obtained were mixed with 40 parts of 2-ethylhexyl acrylate (2-ethylhexyl acrylate) as a reactive diluent (indicates the amount of li, same as below) and 3 parts of benzoin methyl ether as a polymerization initiator. An energy ray-curable resin was obtained.

By applying this energy ray curable resin around the optical fiber obtained by drawing and irradiating it with ultraviolet rays, the first
As shown in the figure, a coated optical fiber 3 was obtained by forming a coating layer 2 around an optical fiber 1.

Further, as shown in FIG. 2, five of these coated optical fibers 3 were laterally arranged and a secondary coating layer 4 was applied to produce a five-core tape core 1/s5.

When the coating of this five-core tape core wire 5 was removed all at once, the pulling force was 0.90 kg, and the coating could be removed very easily.

Example 2 1 mole of polyoxytetramethylene glycol with an average molecular weight of 1000, 2, 2.3.3.4.4.5.5- in a 31 four-bottle flask equipped with a stirrer, a condenser and a thermometer.
Two moles of octafluorohexamethylene diisocyanate were charged, and the mixture was reacted at 60 to 70°C for 2 hours. Then,
2- and 2 moles of droxyethyl acrylate were added, and the infrared absorption spectrum showed that the isocyanate group was 2270 a
The reaction was continued until the characteristic absorption band m-' disappeared.

40 parts of 2-ethylhexyl acrylate as a reactive diluent and 3 parts of benzoin methyl ether as a polymerization initiator were blended with 60 parts of the urethane acrylate oligomer thus obtained to obtain an energy ray curable resin.

Using this energy ray curable resin, a coated optical fiber 3 and a five-core tape core 5 were manufactured in the same manner as in Example 1.

Further, when the coating of this 5-core tape core i%i15 was removed all at once, the pulling force was 0.89 kg, and it could be easily removed.

Example 3 1 mole of polyoxytetramethylene glycol having an average molecular weight of 1000, 3, 3.4.4.5.5.6.6.
7.7.8.2 mol of 8-dotecafluorooctamethylene diisocyanate was charged and reacted at 60 to 70°C for 2 hours.

Next, 2 moles of 2-hydroxyethyl acrylate were added and the infrared absorption spectrum revealed that the isocyanate group was 22
The reaction was continued until the characteristic absorption band at 70 cm-' disappeared.

40 parts of 2-ethylhexyl acrylate as a reactive diluent and 3 parts of benzoin methyl ether as a polymerization initiator were blended with 60 parts of the urethane acrylate oligomer thus obtained to obtain an energy ray curable resin.

Using this energy ray curable resin, a coated optical fiber 3 and a 5-core ribbon ribbon 5 were manufactured in the same manner as in Example 1.

Further, when the coating of the five-core tape core wire 5 was removed all at once, the pulling force was 0.88 kg, and the coating could be easily removed.

Comparative Example 1 1 mol of polyoxytetramethylene glycol with an average molecular weight of 1000 and 2 mol of tetramethylene diisocyanate were placed in a 3I four-bottle flask equipped with a stirrer, a condenser, and a thermometer.
mol was charged and reacted at 60 to 70°C for 2 hours. Next, 2 moles of 2-hydroxyethyl acrylate were added and the infrared absorption spectrum showed that the isocyanate group was 2270
The reaction was continued until the characteristic absorption band of e+n-' disappeared.

To 60 parts of the urethane acrylate oligomer thus obtained, 40 parts of 2-ethylhexyl acrylate as a reactive diluent and 3 parts of benzoin methyl ether as a polymerization initiator were blended to obtain an energy ray-curable resin.

Using this energy ray curable resin, a 5-core tape core was produced in the same manner as in Example 1, and the coating was removed all at once. Therefore, the effect of the present invention cannot be obtained, and the pulling force is 1.5k.
g, and it took a lot of force to remove it.

Comparative Example 2 85 parts of 2-ethylhexyl acrylate and 3 parts of benzoin methyl ether were added as a reaction diluent to 15 parts of urethane acrylate oligomer obtained in the same manner as in Example 1 to obtain an energy ray curable resin.

Using this energy ray curable resin, a 5-core ribbon was produced in the same manner as in Example 1, and the coating was removed all at once. As the content of urethane acrylate oligomer in the energy ray curable resin was small, The effect of the present invention was not noticeable, and the pulling force was 1.3 kg.

Comparative Example 3 85 parts of urethane acrylate oligomer obtained in the same manner as in Example 1 was mixed with 15 parts of 2-ethylhexyl acrylate as a reactive diluent and 3 parts of benzoin methyl ether as a polymerization initiator to produce an energy ray-curable type. Resin was obtained.

Using this energy ray curable resin, a coating layer was formed around the optical fiber in the same manner as in Example 1 to produce a coated optical fiber. However, the viscosity of energy ray-curable resin is
Since the temperature at 25° C. was as high as 20,000 centipoise, the manufactured coated optical fiber was impaired in its appearance and shape.

<Effects of the Invention> As explained above, in the present invention, since fluorine-containing diisocyanate is used as the isocyanate component of the (meth)acrylic oligomer blended into the energy ray curable resin, the coating can be cured without reducing the coating curing speed. A covering layer can be formed, and the formed covering layer can be easily removed. Therefore, even when using a multi-core tape core, the pulling force can be suppressed to 1.0 kg or less.

Further, according to the present invention, unlike conventional products in which silicone oil or the like is added, there is no fear that additives and the like will precipitate over time and impair the appearance and shape.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a coated optical fiber according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a five-core tape core using the coated optical fiber. In the drawings, 1 is an optical fiber, 2 is a coating layer, 3 is a coated optical fiber, 4 is a secondary coating layer, and 5 is a 5-core tape core wire. Figure Figure

Claims (1)

[Claims] 1) A coated optical fiber in which a coating layer is provided by coating an energy ray-curable resin on the outer periphery of the optical fiber and curing it by irradiation with energy rays, which comprises an acrylate or methacrylate component, an isocyanate component, and a polyol. A coated optical fiber characterized by using an energy ray-curable resin having an acrylic or methacrylic oligomer consisting of the following components, a reactive diluent, and a polymerization initiator, and in which the isocyanate component is a fluorine-containing diisocyanate. . 2) A claim in which the fluorine-containing diisocyanate is represented by the following general formula OCNCH_2R_fCH_2NCO (wherein, R_f is a perfluoroalkylene group having 1 to 20 carbon atoms, and also includes those containing one or more ether bonds). 1. The coated optical fiber according to 1. 3) The coated optical fiber according to claim 1 or 2, wherein the energy beam curable resin contains an acrylic or methacrylic oligomer in a proportion of 20% by weight or more and less than 80% by weight.