JP2777289B2 - Composition for optical fiber core material and synthetic resin optical fiber using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for a core material of an optical fiber and a synthetic resin optical fiber using the same.
In particular, the present invention relates to a composition for forming a synthetic resin core of a copolymer and a synthetic resin optical fiber using the same.

[0002]

2. Description of the Related Art In recent years, the development of an optical fiber used as an optical transmitter such as an optical branching device has been advanced, and an optical fiber using silica glass has been particularly applied to a large-capacity long-distance optical communication system. On the other hand, an optical fiber using a synthetic resin has a large transmission loss as compared with a silica glass optical fiber, but has a large numerical aperture (NA) and flexibility and can be manufactured. It has advantages such as easy handling, decoration field such as display,
It is expected to be applied to office automation, factory automation, in-vehicle communication, etc.

[0003] The above synthetic resin optical fiber has a double structure of a core material made of a polymer having good light transmittance and a high refractive index and a clad material made of a polymer having a lower refractive index than the polymer of the core material. It has become. As the core material, generally, a material having excellent permeability, weather resistance, mechanical properties, and the like is selected, and in practice, polymethyl methacrylate is mainly used. It has also been proposed to use a silicone resin as a core material to enhance heat resistance (Japanese Patent Application Laid-Open No. 54-15 / 1979).
0139, JP-A-60-42712, JP-A-60-
43613, JP-A-61-254625, JP-A-61-254625
1-275706, JP-A-63-98603 and JP-A-63-112004).

[0004] However, the above-mentioned conventional synthetic resin optical fibers have the following disadvantages. The synthetic resin optical fiber using polymethyl methacrylate as a core material has a disadvantage that heat resistance is low due to the basic properties of the resin and that it can be practically used only at 100 ° C. or lower. On the other hand, a synthetic resin optical fiber having a silicone resin core has extremely excellent heat resistance, but when used in a hot and humid state, water vapor dissolves in the silicone resin constituting the core, and the temperature or humidity changes. There was a disadvantage that the water vapor in the core sometimes condensed and the light transmittance was significantly reduced.

As described above, the conventional synthetic resin optical fibers as described above have limited applications due to the problem of heat resistance and moisture resistance, and are used in various fields such as factory automation and the automobile industry. There was a high demand for an optical fiber with high performance.

Therefore, in order to improve the moisture resistance of a synthetic resin optical fiber having the above-mentioned silicone resin as a core material, Japanese Patent Application Laid-Open No. 63-16807 discloses a method of providing a metal waterproof layer outside the optical fiber. JP-A-63-253303 proposes a method in which a silicone resin having hydrophilicity is used as a core material.

[0007]

However, Japanese Patent Application Laid-Open No.
In the method of No. 16806, although the moisture resistance is improved,
Since it is necessary to provide a metal water-impermeable layer, the configuration of the optical fiber becomes complicated, and the fiber becomes rigid and difficult to handle. Also, JP-A-63-
According to the method of No. 253303, improvement in moisture resistance was insufficient.

[0008]

Accordingly, an object of the present invention is to provide a composition for a core material for obtaining a synthetic resin optical fiber which is excellent in heat resistance and moisture resistance and is easy to handle, and a synthetic resin optical fiber using the core. is there.

[0009]

DISCLOSURE OF THE INVENTION The present invention relates to a composition for an optical fiber core material, which comprises an organosiloxane and a compound represented by the following formula (5) in order to obtain a synthetic resin optical fiber having excellent heat resistance and moisture resistance and easy to handle.

Embedded image (However, R _A is hydrogen or a methyl group, R _B is hydrogen or a carbon number of 1 to 18 substituted or unsubstituted monovalent hydrocarbon group.) And a carboxylic acid ester represented by essential components, before
The organosiloxane has the following

The components (a), (b), and
Contains component (c).

As described above, an optical fiber using a silicone resin for the core has a disadvantage that it is generally excellent in heat resistance but inferior in moisture resistance as compared with an optical fiber using the polymethyl methacrylate resin for the core. I was Therefore, as a result of examining the improvement of moisture resistance, it was found that if a copolymer of an organosiloxane and a carboxylic acid ester represented by the above formula (5) is used as a core material, a synthetic material having excellent heat resistance and moisture resistance and easy handling can be obtained. It has been found that a resin optical fiber can be obtained.

(Organosiloxane) The organosiloxane contained as an essential component in the core material composition of the present invention is a compound obtained by copolymerizing with a carboxylic acid ester represented by the above formula (5) for use as an optical fiber core. There is no particular limitation as long as the required transparency is satisfied. However, in consideration of copolymerizability with the carboxylic acid ester and moisture resistance, the following compounds are selected . That is, (a) In the molecule,

Embedded image (Where R _C is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms) and an alkenyl group directly bonded to a silicon atom in an amount of 0% per silicon atom. (B) an organosiloxane containing at least two hydrogen atoms per molecule directly bonded to a silicon atom, and (c) a platinum catalyst and a radical. One or both of the polymerization initiators are respectively contained .

Regarding the component (a), in the organosiloxane of the component (a), the organosiloxane structure before curing contains the three-dimensional structural unit represented by the formula (6) in order to increase the crosslinking density. is there. In addition, moisture resistance
From the viewpoint of increasing the total weight of the above components (a) and (b)
In the organosiloxane of the component (a) with respect to the amount of 100 g
It is desirable to contain at least 0.02 mol of silanol groups of
New By using such an organosiloxane, the transparency and moisture resistance of the copolymer are improved.

In the above formula, R _c has 1 to 1 carbon atoms.
0 is a substituted or unsubstituted monovalent hydrocarbon group, specifically, for example, an alkyl group such as a methyl group, an ethyl group, and a propyl group, an alkenyl group such as a vinyl group, an allyl group, and a hexenyl group; group, a tolyl group, ants such as xylyl
Thiol group , tetrachlorophenyl group, chlorophenyl group,
Examples include a halogen-substituted monovalent hydrocarbon group such as a chloromethyl group, a pentafluorobutyl group, and a trifluoropropyl group. Among these, a methyl group, a phenyl group, and a vinyl group are particularly preferred. The proportion of these substituents is not particularly limited, but the proportion of the structural unit represented by Formula 6 is
It is preferable that the organosiloxane of the component (a) be contained in a proportion of 30 to 80 mol%, particularly 40 to 70 mol%.

The organosiloxane of component (a) is
In the presence of a hydrogen atom directly bonded to a silicon atom of the organosiloxane of the component (b) and a platinum catalyst or a radical polymerization initiator of the component (c), the composition is cured by an addition crosslinking reaction.
In this method, an alkenyl group such as a vinyl group, an allyl group, or an acryl group directly bonded to a silicon atom in an organosiloxane is copolymerized with a carboxylic acid ester represented by the above formula (5). For this reason, a vinyl group directly connected to a silicon atom,
The alkenyl group such as an allyl group and an acryl group is preferably contained at least 0.05, more preferably at least 0.15 per silicon atom in one molecule of the organosiloxane. When the number of alkenyl groups is less than 0.05 per silicon atom, there arises a problem that the curing speed becomes slow or a cured product cannot be obtained.

The organosiloxane of the component (a) is used to improve the moisture resistance and copolymerizability of the optical fiber by adding a silanol group (SiOH) to the total weight of the components (a) and (b) to 100 g. 0.02 mol or more,
In particular, it is preferably contained in an amount of 0.04 mol or more. When the amount of the silanol group is less than 0.02 mol, the obtained copolymer has poor moisture resistance.

Component (b) Component (b) is an organosiloxane having at least two hydrogen atoms in one molecule directly bonded to a silicon atom, and is added to an alkenyl group in the organosiloxane of component (a). It is a component for copolymerization by a cross-linking reaction or an addition reaction with a carboxylic acid ester represented by the above formula (5).

In this case, the ratio of the number of hydrogen atoms B directly bonded to silicon atoms in the organosiloxane of the component (b) to the number of alkenyl groups A in the organosiloxane of the component (a) is determined by good curing characteristics and A / B is not particularly limited as long as transparency of the copolymer obtained with the carboxylic acid ester represented by
It is desirable that the molar ratio be 10/1 to 1/10, particularly 5/1 to 1/5.

In the organosiloxane of component (b), the organic group bonded to a silicon atom other than a hydrogen atom is not particularly limited as long as it is a monovalent organic group, but may be a monovalent substituted or unsubstituted hydrocarbon. Groups are preferred. The monovalent substituted or unsubstituted hydrocarbon group includes the component (A) R
Examples include the same alkyl group, aryl group , and halogen-substituted monovalent hydrocarbon group as in _c, with a methyl group and a phenyl group being particularly preferred.

Component (c) The core composition of the present invention is obtained by a copolymerization reaction of a precursor of the resin composition comprising the organosiloxane and the carboxylic acid ester. Platinum catalysts such as acids, or benzoyl peroxide,
Peroxides such as dicumyl peroxide and lauroyl peroxide, azobisisobutyronitrile, azobis-
When the reaction is carried out under a condition in which a radical polymerization initiator represented by an azo compound such as (2,4-dimethylvaleronitrile) or a platinum-based catalyst is used in combination with a radical polymerization initiator, appropriate energy such as heat or ultraviolet light is applied. Promoted.

When a platinum-based catalyst is used as the above catalyst, the polymerization reaction proceeds even at around normal temperature, and the progress of the reaction is further accelerated under heating. Therefore, a reaction inhibitor may be added from the viewpoint of operation. Examples of the reaction inhibitor include acetylene alcohols, 3-methyl-butyn-2-ol, 2-methyl-1-pentyl-3-ol, and 3,5-dimethyl-1-hexyne-3-ol.
All, 2,5-dimethyl-3-hexyne-2,5-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5-decyne-
4,7-diol and the like. The addition amount of the reaction inhibitor is not particularly limited, and may be appropriately selected according to the working conditions.

(Carboxylic acid ester) The carboxylic acid ester represented by the formula (5) is, for example, an acrylate or a methacrylate, and copolymerizes with the above-mentioned organosiloxane to contribute to an improvement in moisture resistance. .

In the formula, R _B is a substituted or unsubstituted monovalent hydrogen oxide group having 1 to 18 carbon atoms.
For example, alkyl groups such as methyl group, ethyl group and propyl group, alkenyl groups such as vinyl group, allyl group and hexenyl group, and aryl groups such as phenyl group, tolyl group and xylyl group
And halogen-substituted monovalent hydrocarbon groups such as a tetrachlorophenyl group, a chlorophenyl group, a chloromethyl group, a 2,2,2-trifluoroethyl group, a pentafluorobutyl group and a trifluoropropyl group.

The content of the carboxylic acid ester represented by the formula (5) in the whole core composition is 0.5 to 0.5 by weight.
Although it may be in the range of 50% by weight, particularly 1 to 30% by weight
Is preferable. When the content of the carboxylic acid ester is less than 0.5% by weight, the moisture resistance of the obtained optical fiber is not sufficiently improved. On the other hand, when the content exceeds 50% by weight, the copolymerizability becomes poor and the core becomes transparent. This causes a problem that the performance is insufficient.

(Clad Material) Next, the clad material constituting the optical fiber together with the above-mentioned core material is not particularly limited, and a known material can be used. However, the refractive index of the clad material must be smaller than the refractive index of the core material described above,
In particular, a polymer having a refractive index smaller than 1% is desirable.

Examples of such a clad material include polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, vinylidene fluoride / terafluoroethylene copolymer, tetrafluoroethylene / Vinylidene fluoride copolymer, tetrafluoroethylene / perfluoroalkylvinyl ether copolymer, chlorotrifluoroethylene polymer, 4-methyl-1-pentene polymer, organosiloxane polymer, fluorine-containing acrylate or methacrylate polymer, etc. Is given as an example.

[0026]

Next, an embodiment of the present invention will be described. The above-mentioned organosiloxanes and carboxylic esters were variously selected, and nine types of core material compositions of Examples 1 to 9 shown below were produced. Further, an optical fiber having a cross section as shown in FIG. 1 was prepared using these core material compositions. The optical fiber 10 has a clad 1 around a core 11.
2 has a double structure covering.

The following tests were conducted to examine the properties of the core material composition and the optical fiber using the same. Each of the optical fibers using the core compositions of Examples 1 to 9 was manufactured in order to compare them with Comparative Examples 1 to 9.
With the optical fiber of No. 3, an initial transmission loss and moisture resistance test were performed by the following method.

(Transmission Loss) The optical transmission performance was evaluated based on the magnitude of the transmission loss a by the following cutback method. First, light of a predetermined wavelength obtained by dispersing a light source of a halogen lamp with a monochromator is converted into a light having a length L as shown in FIG.
₁ m is incident from one end of the optical fiber, and the light quantity P ₁ (W) at the other end is measured. Next, this optical fiber is
₂ (m), the same light as above is incident from one end of the optical fiber from one end, and the light amount P
₂ Measure (W). The transmission loss a (dB / m) is given by Equation 1.
Obtained from the formula.

(Equation 1) In this embodiment, the wavelength is 660 nm, L ₁ = 5 m,
The measurement was performed under the condition of L ₂ = 1 m.

(Moisture Resistance) The moisture resistance was evaluated based on the light quantity retention rate determined by the following method. Temperature is 60 ° C
The optical fiber to be tested is put in a constant temperature / humidity chamber having a relative humidity of 90%, the optical fiber is taken out from the constant temperature / humidity chamber every predetermined time, and after 30 minutes, the transmitted light amount of the 660 nm LED light source is measured. The light quantity holding ratio (%) was determined from the equation (2).

(Equation 2)

Next, the compositions of the respective examples and comparative examples and a method of manufacturing an optical fiber using the same will be described. In addition, the organosiloxane represented by the chemical formula (7) or (8) is used for the component (a), and the organosiloxane represented by the chemical formula (9) is used for the component (b). Was.

Embedded image

Embedded image

Embedded image Me represents a methyl group, and Vi represents a vinyl group. Also,
All parts in the following examples and comparative examples indicate parts by weight.

[0031]

EXAMPLE 1 10 parts of methyl methacrylate, 52.2 parts of a component represented by the formula (hereinafter, referred to as "Chemical component 7"), and a component represented by the formula (Chemical formula 8). )) 2
0.3 part, 17.5 parts of a component represented by the following chemical formula (hereinafter referred to as “a chemical 9 component”), and lauroyl peroxide 0.0
To 5 parts, an octyl alcohol-modified solution of chloroplatinic acid was added so as to be 0.9 ppm of platinum.

The obtained core composition precursor was coated with a cladding material of tetrafluoroethylene / hexafluoropropylene copolymer having an inner diameter of 1.5 mm and an outer diameter of 2.2 mm.
After injecting into a tube at 150 ° C. for 1 hour and 150 ° C.
The mixture was heated at a temperature of 5 ° C. for 5 hours to cure the precursor of the core composition, thereby obtaining the optical fiber of Example 1.

[0033]

Example 2 10 parts of benzyl methacrylate, chemical formula 5 component 5
2.2 parts, 20.3 parts of Chemical Formula 8, and 17.5 parts of Chemical Formula 8 and 0.05 part of lauroyl peroxide were used to prepare a solution of octyl alcohol modified with chloroplatinic acid as platinum at 0.
It was added to 9 ppm. Using the obtained core composition precursor, the same clad material as used in Example 1,
And the optical fiber of Example 2 was obtained using the same method.

[0033]

Example 3 10 parts of ethyl methacrylate, chemical formula 5
To 2.2 parts, 20.3 parts of the chemical formula 8, 17.5 parts of the chemical formula 9 and 0.05 parts of lauroyl peroxide, 0.9% of octyl alcohol-modified chloroplatinic acid as platinum was used.
ppm was added. An optical fiber of Example 3 was obtained from the obtained core composition precursor using the same clad material as used in Example 1 and using the same method.

[0034]

Example 4 10 parts of 2,2,2-trifluoroethyl methacrylate, 52.2 parts of Chemical Formula 7, and 20.3 of Chemical Formula 8
Octyl alcohol-modified solution of chloroplatinic acid was added to 0.9 parts by weight of platinum to 17.5 parts of the compound, 17.5 parts of the chemical formula 9, and 0.05 part of lauroyl peroxide. An optical fiber of Example 4 was obtained from the obtained core composition precursor using the same clad material as used in Example 1 and using the same method.

[0035]

Example 5 10 parts of n-butyl acrylate, chemical formula 5
To 2.2 parts, 20.3 parts of the chemical formula 8, 17.5 parts of the chemical formula 9 and 0.05 parts of lauroyl peroxide, 0.9% of octyl alcohol-modified chloroplatinic acid as platinum was used.
ppm was added. An optical fiber of Example 5 was obtained from the obtained core composition precursor using the same clad material as used in Example 1 and using the same method.

[0036]

Example 6 25 parts of methyl methacrylate, chemical formula 4
To 0.6 part, 15.8 parts of Chemical Formula 8, 13.6 parts of Chemical Formula 9, and 0.05 part of lauroyl peroxide, 0.9% of an octyl alcohol-modified chloroplatinic acid solution as platinum was used.
ppm was added. The optical fiber of Example 6 was obtained from the obtained core composition precursor using the same clad material as used in Example 1 and using the same method.

[0037]

Example 7: 10 parts of methyl methacrylate, compound 7
0.2 parts of a octyl alcohol-modified solution of chloroplatinic acid was 0.9 ppm as platinum with respect to 0.2 part, 4 parts of the formula 8, 15.8 parts of the formula 9, and 0.05 part of lauroyl peroxide.
Was added so that The optical fiber of Example 7 was obtained from the obtained core composition precursor using the same clad material as used in Example 1 and using the same method.

[0038]

Example 8 10 parts of methyl methacrylate, chemical formula 5 component 5
An octyl alcohol-modified solution of chloroplatinic acid was added to 2.2 parts, 20.3 parts of Chemical Formula 8, and 17.5 parts of Chemical Formula 9 so as to be 1 ppm of platinum. An optical fiber of Example 8 was obtained from the obtained core composition precursor using the same clad material as used in Example 1 and using the same method.

[0039]

Example 9 10 parts of methyl methacrylate, compound 7
2.2 parts, 20.3 parts of Chemical Formula 8, 17.5 parts of Chemical Formula 9, and 0.05 part of lauroyl peroxide were mixed. The optical fiber of Example 9 was obtained from the obtained core composition precursor using the same clad material as used in Example 1 and using the same method.

[0040]

Comparative Example 1 60 parts of methyl methacrylate, compound 29
Octyl alcohol-modified solution of chloroplatinic acid was added to 0.9 parts by weight of platinum to 11.3 parts, 11.3 parts of Chemical Formula 8, 9.7 parts of Chemical Formula 9, and 0.05 part of lauroyl peroxide. The obtained core composition part precursor,
An optical fiber of Comparative Example 1 was obtained using the same clad material as used in Example 1 and using the same method.

[0041]

Comparative Example 2 Methyl methacrylate 0.2 part, Chemical formula 7 component 5
To 7.9 parts, 22.5 parts of Chemical Formula 8, 19.4 parts of Chemical Formula 9, and 0.01 part of lauroyl peroxide, 0.9% of octyl alcohol-modified chloroplatinic acid was converted to platinum.
ppm was added. The obtained core composition precursor was used, using the same clad as used in Example 1,
An optical fiber of Comparative Example 2 was obtained using the same method.

[0042]

Comparative Example 3 An octyl alcohol-modified solution of chloroplatinic acid was added to 58 parts of the chemical formula 7, 22.6 parts of the chemical formula 8, and 19.4 parts of the chemical formula 9 so as to be 1.0 ppm of platinum. An optical fiber of Comparative Example 3 was obtained from the obtained core composition precursor using the same clad material as used in Example 1 and using the same method.

[0043]

[Evaluation of Characteristics of Each Example] Table 1 shows various characteristics of each example and each comparative example.

[Table 1]

In Table 1, the content (% by weight) of the carboxylic acid ester represented by Formula 5 in the core composition and the content (mol) of the silanol group in the organosiloxane in the core composition are shown in Table 1. / 100 g), the initial transmission loss (dB / m) of each optical fiber, and the temperature of the optical fiber at 60 ° C.
It shows the light quantity holding ratio after standing at 90% relative humidity for 1000 hours.

As can be seen from the table, each of the optical fibers of the examples had a relatively small initial transmission loss and a good light quantity holding ratio, whereas the optical fiber of the comparative example had a poor light quantity holding rate. In particular, the core of the optical fiber of Comparative Example 1 was opaque and had no light transmission performance.

FIG. 3 shows a Y-branched optical waveguide substrate manufactured using the composition for a core material of the present invention. Y-branch optical waveguide substrate 2
0 denotes a poly 4- having a Y-shaped groove 21 by injection molding.
A substrate 22 of a methyl-1-pentene polymer was prepared, and a groove 2 was formed.
The core composition precursor of Example 1 was poured onto
Obtained by heating at 10 ° C. for 10 hours. The core 23 is obtained by curing and molding the core composition precursor poured into the groove by the heating. The Y-branch optical waveguide substrate 20 has a temperature of 6
Even after being left at 0 ° C. and 90% relative humidity for 1000 hours, it had excellent light guide performance.

[0047]

As described above, the optical fiber using the optical fiber core composition of the present invention is excellent in heat resistance and moisture resistance and is easy to handle, so that the field of application of the synthetic resin optical fiber is expanded. Things.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical fiber according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a transmission loss measuring method.

FIG. 3 is a perspective view showing a Y-branch optical waveguide substrate according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 optical fiber 11 core 12 clad 20 Y-branched optical waveguide substrate 21 groove 22 substrate 23 core

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-273804 (JP, A) JP-A-3-144404 (JP, A) Patent 2550724 (JP, B2) (58) Fields studied (Int. Cl. ^6, DB name) G02B 6/00 391 C08L 83/05 C08L 83/06 C08L 83/07 G02B 6/12

Claims (4)

(57) [Claims] 1. An organosiloxane and a compound represented by the following formula: (However, R _A is hydrogen or a methyl group, R _B is hydrogen or a carbon number of 1 to 18 substituted or unsubstituted monovalent hydrocarbon group.) And a carboxylic acid ester represented by the essential components
The organosiloxane has the following formula (a) : (However, R _C is a substituted or unsubstituted _C 1-10 carbon atom.)
Is a monovalent hydrocarbon group. ) And the unit
An alkenyl group directly connected to an iodine atom
Each containing at least 0.05 silanol groups
And (ii) a hydrogen atom directly bonded to a silicon atom for at least 1 minute.
Organosiloxane having two or more per child, also one of (c) platinum catalyst and a radical polymerization initiator
Is an optical fiber core characterized by containing both
Material composition. 2. The composition for a core material of an optical fiber according to claim 1, wherein the composition contains 0.5 to 50% by weight of the carboxylic acid ester represented by the formula (1). 3. It has a core and a clad, wherein the core is:
Organosiloxane and Formula 3 (However, R _A is hydrogen or a methyl group, R _B is hydrogen or a carbon number of 1 to 18 substituted or unsubstituted monovalent hydrocarbon group.) A carboxylic acid ester represented by the essential components,
The organosiloxane is represented by (a) a molecule represented by the following formula : (However, R _C is a substituted or unsubstituted _C 1-10 carbon atom.)
Is a monovalent hydrocarbon group. ) And the unit
An alkenyl group directly connected to an iodine atom
Each containing at least 0.05 silanol groups
And (ii) a hydrogen atom directly bonded to a silicon atom for at least 1 minute.
Organosiloxane having two or more in the child, and either (c) a platinum catalyst and a radical polymerization initiator
Is a synthetic resin optical fiber characterized by containing both
Ba. 4. The synthetic resin optical fiber according to claim 3, wherein the composition which is a raw material of the synthetic resin constituting the core contains 0.5 to 50% by weight of the carboxylic acid ester represented by the formula ( 3 ). .