JPH0222610A - Coated optical fiber - Google Patents

Abstract

PURPOSE:To improve adhesiveness and moisture resistance characteristic by using a specific energy ray curing type resin. CONSTITUTION:Alkoxyisocyanate silane is used as the isocyanate component of the methacrylic oligomer to be compounded with the energy ray curing type resin. The methacrylic oligomer generates a siloxane bond with the surface of the optical fiber after curing of the alkoxyisocyanate silane incorporated as the isocyanate component therein. The adhesive property of the coating layer and the optical fiber is improved in this way and the moisture resistant characteristic is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Minute Hand> The present invention relates to a coated optical fiber i% 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 (especially optical glass fibers and quartz-based glass fibers), it is considered preferable to immediately apply a plastic coating to the outer periphery of the fibers after they are made into fibers. 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 turned 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. Demand for UV resin-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 may be 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.
There is a problem that coating layers using these resins may deteriorate the strength of the optical fiber when they absorb moisture.

In addition, there are attempts to improve the adhesion of the coating layer by using additives such as silane coupling agents in the above-mentioned resins, but even with such additives, it is not possible to improve the moisture resistance properties. I can hardly do it.

Therefore, a silane coupling agent having an amino group has been proposed as an additive for improving such moisture resistance characteristics (Japanese Patent Laid-Open No. 59-92947).

<Problems to be Solved by the Invention> In order to improve the moisture resistance properties using the silane coupling agent having an amino group as described above, it is necessary to add a large amount of the silane coupling agent, which in this case is caused by energy rays. A problem arises in that the curing speed of the curable resin becomes slow, leading to a decrease in production. In addition, since silane coupling agents with amino groups do not contain polymerizable carbon/carbon double bonds in their molecules, if they are used in large quantities, there is a risk of precipitation from the coating layer after curing at the interface between the optical fiber and the coating layer. There is.

In view of the above-mentioned circumstances, the present invention has been developed to form a coating layer that adheres well to an optical fiber and has excellent moisture resistance without reducing the curing speed, and which allows additives to bond with the optical fiber from the coating layer over time. An object of the present invention is to provide a coated optical fiber that is free from the risk of precipitation at the interface.

<*Means for solving the problem> 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 an alkoxyisocyanate silane.

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 containing 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 the resin is usually 100 at 25°C.
It is preferable to adjust it within the range of 0 to 10,000 centipoise.

Furthermore, 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 an alkoxyisocyanate silane is used as the isocyanate component.

In such a (meth)acrylic oligomer, the alkoxyleisocyanate silane contained as an isocyanate component forms a siloxane bond with the optical fiber surface after curing. Therefore, the adhesion between the coating layer and the optical fiber is improved, and moisture resistance is improved.

Additionally, since alkoxyisocyanates are used as the isocyanate component in (meth)acrylic oligomers, unlike the case of silane coupling agents with amino groups, there is a risk that they will precipitate at the interface between the coating layer and the optical fiber over time. Nor.

Here, the 1-rukoxyisocyanate tolerane includes dimethoxysilyl diisocyanate, jetoxysilyl diisocyanate-1.,1,1.2.2-tetramethoxydiisocyanate disilane, 1,1,2,2-tetraethoisylane-1. Examples include diisocyanate disilane.

Further, as the (meth)acrylate component, those having a hydroxyalkyl 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, polycaprolactone polyols, and the like are used.

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

2-Ethylhexyl (meth)acrylate, (meth)acrylate of tetrahydrofurfuryl alcohol caprolactone adduct, (meth)acrylate of nonylphenol ethylene oxide adduct, polyprolene glycol di(meth)acrylate, polypropylene glycol di( meth)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.

Furthermore, the following vinyl compounds can also be used 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, Benzyl~ 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 may be used together with these initiators.

The amount of the polymerization initiator added is the total of the (meth)acrylic oligomer and the reactive diluent; ilo.

It may be used in an amount of usually about 1 to 10 parts by weight, preferably 1 to 5 parts by weight.

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.

Example of implementation〉 The following is a book! A preferred embodiment and a comparative example for comparison will be described.

Example 1 1 mole of polyoxytetramethylene glycol with an average molecular weight of 1000 and 2 moles of dimethoxysilyl diisocyanate were charged into a 3I four-bottle flask equipped with a stirrer, a condenser, and a thermometer, 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 23
The reaction was continued until the characteristic absorption band at 00 cm-' disappeared.

60 parts of the urethane acrylate oligomer thus obtained were mixed with 2-ethylhexyl acrylate 401 (indicated by weight, hereinafter the same) as a reactive diluent and 3 parts of benzoin methyl ether as a polymerization initiator, and then energy rays were added. A 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.

A 1 m long coated optical fiber 3 was wound around a mandrel having a length of 50 en and a diameter of 3 m, and was immersed in water. The coated optical fiber broke after 7 days, indicating that the #4 moisture properties of the coating layer were excellent.

Example 2 1 mole of polyoxytetramethylene glycol with an average molecular weight of 1000 and 2 moles of jetoxysilyl diisocyanate were charged into a 3I four-bottle flask equipped with a stirrer, a condenser, and a thermometer, and the mixture was heated at 60 to 70°C for 2 hours. Made it react.

Then, 2 moles of 2-hydroxyethyl acrylate were added, and the infrared absorption spectrum showed 23 of the isocyanate group.
The reaction was continued until the characteristic absorption band of 00(7)-1 disappeared.

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

A coated optical fiber 3 was manufactured in the same manner as in Example 1 using this energy ray curable resin.

When this coated optical fiber 3 was subjected to the same test as in Example 1, it took 7 days to break, and it was confirmed that it also had excellent moisture resistance.

Example 3 1 mole of polyoxytetramethylene glycol having an average molecular weight of 1000 and 2 moles of 1,1,2.2-tetramethoxydiisocyanate disilane were charged into a 31-meter four-bottle flask equipped with a stirrer, a condenser, and a thermometer. ~70℃
The mixture was allowed to react for 2 hours. Then, 2 moles of 2-hydroxyethyl acrylate were added and the reaction was continued until the characteristic absorption band of the isocyanate group at 2300 an' disappeared according to an infrared absorption spectrum.

In this way, 40 parts of 2-ethylhexyl acrylate as a reactive diluent and 3 parts of benzoin methyl ether as a 171 initiator were blended with 60 parts of the urethane acrylate oligomer prepared above to obtain an energy ray-curable resin. .

A coated optical fiber 3 was manufactured using this energy ray curable resin in the same manner as in Example 1.

When this coated optical fiber was subjected to the same test as in Example 1, it took 8 days to break, and it was found that it still had excellent moisture resistance.

Comparative Example 1 In a 3I four-bottle flask equipped with a stirrer, a condenser, and a thermometer, 1 mol of polyoxytetramethylene glycol with an average molecular weight of xooo and 2 mol of tetramethylene diisocyanate were added.
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 am-' 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 fi polymerization initiator were blended to form an energy ray-curable resin. I got it.

A coated optical fiber 3 was manufactured in the same manner as in Example 1 using this energy ray curable resin.

When this coated optical fiber was tested in the same manner as in Examples 1 and n, it was found that since no alkoxyisoleanato silane was used, the #4 humidity characteristics were poor, and the time until the optical fiber broke was as short as 20 hours. .

Comparative Example 2 5 parts of urethane acrylate oligomer obtained in the same manner as in Example 1 were mixed with 95 parts of 2-ethylhexyl acrylate and 3 parts of benzoin methyl ether as reaction diluents to obtain an energy ray-curable resin.

A coated optical fiber was manufactured in the same manner as in Example 1 using this energy ray curable resin.

When the same test as in Example 1 was conducted, it was found that because the content of urethane acrylate oligomer in the energy beam curable resin was small, the moisture resistance did not improve and the time it took for the optical fiber to break was as short as 24 hours. Ta.

Comparative Example 3 95 parts of urethane acrylate oligomer obtained in the same manner as in Example 1 were mixed with 5 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 13,000 centipoise, the manufactured coated optical fiber was impaired in its appearance and shape.

<Effects of the Invention> As explained above, in the present invention, alkoxyreisocyanate silane is used as the isocyanate component of the (meth)acrylic oligomer blended into the energy ray curable resin, so it has good adhesion and moisture resistance. We can provide superior coated optical fibers. Further, the tear-colored energy ray-curable resin of the present invention does not have the disadvantage of a decrease in curing speed, and there is no fear that additives will precipitate at the interface with the optical fiber after curing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a coated optical fiber according to an embodiment of the present invention. In the drawing, 1 is an optical fiber, 2 is a coated stone, and 3 is a coated optical fiber. Patent application agent Sumitomo Electric Industries Co., Ltd.

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 in that it uses 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 an alkoxyisocyanate silane. . 2) The above alkoxyisocyanate silane is represented by the following general formula ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (However, R is an alkyl group such as a methyl group or an ethyl group or an aryl group, and n represents a repeating unit.) The coated optical fiber according to claim 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 10% by weight or more and less than 90% by weight.