JP2560526B2 - Composition for optical fiber core and optical fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to an organopolysiloxane composition used as a core material of a plastic optical fiber and a plastic optical fiber having a cured product of the composition as a core.

[Problems to be Solved by Conventional Techniques and Inventions] As is well known, in addition to glass-based optical fibers having silica glass or multi-component glass as a core component or a sheath (clad) component, as is well known. There is a plastic optical fiber made of plastic for both the core component and the sheath component. Compared to glass-based optical fiber, this plastic optical fiber
Although it has a drawback that it has a large transmission loss and is not suitable for long-distance communication, it has advantages that it has a larger numerical aperture, is easier to handle, and is cheaper than a glass-based optical fiber.

Conventionally, a plastic optical fiber is usually composed of a core made of an organic polymer having good light transmittance and a sheath made of an organic polymer having a smaller refractive index than the core component and having good transparency. In this case, polymethylmethacrylate, polystyrene, etc. are known as an organic polymer having a good light-transmitting property suitable as a core substance. Furthermore, in recent years, it has been proposed in JP-A-60-43613 to use an organopolysiloxane elastic body as a core substance, and a plastic optical fiber using this as a core substance has polymethyl methacrylate as a core component. It has the advantages of being more flexible and superior in heat resistance than those of other products.

However, when the organopolysiloxane is applied as a core component of a plastic optical fiber, it has a drawback that the optical transmission loss increases in a short time when left under high humidity conditions, and it is desired to solve this drawback. It was

The present invention has been made in view of the above circumstances, and has a composition for an optical fiber core that gives an organopolysiloxane cured product having a small optical transmission loss even under high humidity conditions, and the cured product as a core. An object is to provide an optical fiber.

[Means and Actions for Solving the Problems]

The present inventor has conducted extensive studies in order to achieve the above object, and as a result, (A) The following formula (1) and formula (2) in the molecule RSiO _1.5 (1) (Provided that R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a is 0, 1 or 2, and b is an integer of 1 to 6). An organopolysiloxane having 0.05 or more alkenyl groups directly bonded to a silicon atom per silicon atom, and (B) an organopolysiloxane having at least two hydrogen atoms directly bonded to a silicon atom in one molecule. An organopolysiloxane composition containing (C) a platinum-based catalyst is very effective as a composition for a core of an optical fiber, and an optical fiber having a cured product of the composition applied to the core has a high humidity condition. It has been found that the light transmission does not decrease even when exposed to a lower surface for a long time, and the optical transmission loss is small.

That is, in order to increase the crosslink density, the above organopolysiloxane composition has RS represented by the above formula (1) which is a three-dimensional constitutional unit in the organopolysiloxane structure before curing.
It has _1.5 units of iO and is represented by the above formula (2) in order to improve the moisture resistance. It has a unit, and by using such an organopolysiloxane, a high light transmittance can be stably maintained against a change in humidity.

Therefore, the present invention provides a composition for an optical fiber core containing the organopolysiloxane as the component (A), the organopolysiloxane as the component (B), and the platinum-based catalyst as the component (C), and curing of the composition. An optical fiber having an object as a core is provided.

 Hereinafter, the present invention will be described in more detail.

The organopolysiloxane of the component (A) that constitutes the organopolysiloxane composition for the core of the optical fiber of the present invention has the following three-dimensional constitutional unit (1), RSiO _1.5 (1) and the following unit (2) having an amide bond. ) And has at least 0.05 alkenyl groups directly bonded to silicon atoms per silicon atom.

Here, in the three-dimensional structural unit (1) and the unit (2) having an amide bond, R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms. Specific examples include alkyl groups such as methyl group, ethyl group and propyl group, alkenyl groups such as vinyl group, allyl group and hexenyl group, cycloalkyl groups such as cyclohexyl group, phenyl group, tolyl group and xylyl group. Examples of the aryl group, benzyl group, aralkyl group such as phenylethyl group, tetrachlorophenyl group, chlorophenyl group, chloromethyl group, pentafluorobutyl group, and halogen-substituted monovalent hydrocarbon group such as trifluoropropyl group. Of these, a methyl group, a phenyl group, and a vinyl group are preferable, and the ratio of these substituents is not particularly limited.

The organopolysiloxane of the component (A) preferably contains the three-dimensional constitutional unit of the above formula (1) in an amount of 30 to 80 mol%, particularly 40 to 70 mol%, and the other constitutional units include In addition to the constitutional unit having an amide bond represented by the formula (2), R ₂ SiO unit, R ₃ SiO _0.5 unit (R has the same meaning as described above), SiO ₂ unit and the like can be mentioned.

Next, in the constitutional unit having an amide bond of the formula (2) which is essentially contained in the component (A) for improving the moisture resistance, R has the same meaning as described above, and a is 0, 1 or 2 , B
Represents an integer of 1 to 6, but b is preferably 3 in terms of ease of synthesis. The constituent unit represented by the formula (2) should be contained in an amount of 0.02 mol or more, particularly 0.04 mol or more based on 100 g of the total weight of the components (A), (B) and (C). Is preferred.

Further, the organopolysiloxane of the component (A) is
It cures by an addition cross-linking reaction in the presence of a hydrogen atom directly connected to a silicon atom of the organopolysiloxane of the component (B) and a platinum-based catalyst of the component (C), which will be described later. One alkenyl group such as vinyl group, allyl group, and acryl group directly linked to a silicon atom per silicon atom
It is necessary to have 0.05 or more, preferably 0.15 or more. If the number of alkenyl groups directly connected to the silicon atom is less than 0.05 per silicon atom, the curing speed will be slow or a cured product will not be obtained.

The organopolysiloxane of component (A) is
From the low viscosity of about 100cs at 25 ℃, 10,
A wide range of materials can be used, including those with high viscosities exceeding, 000,000cs, but the three-dimensional constitutional unit of the above formula (1) is usually 30-
In the case of containing 80 mol%, the resin generally has a three-dimensional structure at room temperature.

The organopolysiloxane of the component (A) having the three-dimensional constitutional unit of the formula (1), the constitutional unit (2) having the amide bond of the formula (2) and the alkenyl group is specifically shown by the following average composition formula. What is done is illustrated. In addition,
Me is a methyl group, Vi is a vinyl group, and Ph is a phenyl group.

(However, each of l, m, n, p, and q is a positive number less than 1.) These organopolysiloxanes co-hydrolyze the alkoxysilane or halogenosilane corresponding to each constituent unit in the above formula. It can be obtained by a known method.

Next, the component (B) which constitutes the organopolysiloxane composition for a core of the present invention is an organopolysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule. It is a component for forming a cured product by addition crosslinking reaction with the alkenyl group in the organopolysiloxane of component A). In this case, the ratio of the hydrogen atom (Y) directly bonded to the silicon atom in the organopolysiloxane of the component (B) to the alkenyl group (X) in the organopolysiloxane of the component (A) is sufficient to achieve the curing purpose. Although there is no particular limitation, Y / X is 1 in a molar ratio.
It is preferably 0/1 to 1/10, particularly 5/1 to 1/5.

In this organopolysiloxane of component (B),
As an organic group bonded to a silicon atom other than a hydrogen atom,
It is not particularly limited as long as it is a monovalent organic group similar to R in the component (A) described above, but a monovalent unsubstituted or substituted hydrocarbon group having 1 to 8 carbon atoms excluding an alkenyl group is preferable. Examples of the monovalent unsubstituted or substituted hydrocarbon group excluding the alkenyl group include the same alkyl groups, aralkyl groups, and halogen-substituted monovalent hydrocarbon groups as R of the component (A) described above, A methyl group and a phenyl group are preferred. The molecular structure of the organopolysiloxane of the component (B) is not particularly limited as long as it is compatible with the organopolysiloxane of the component (A), and may be, for example, cyclic, chain-like, branched or three-dimensional network. It doesn't matter. Furthermore, a wide range of viscosities from low viscosities of 10 cs or less to high viscosities of 1000 cs or more at 25 ° C. can be used, but from the viewpoint of optical fiber production, low-viscosity organopolysiloxane compositions are preferred. In order to reduce the viscosity of the composition, the organopolysiloxane as the component (B) preferably has a low viscosity of 1000 cs or less.

The platinum-based catalyst of the component (C) which constitutes the organopolysiloxane composition for a core of the present invention is composed of a silicon-bonded alkenyl group in the organopolysiloxane of the component (A) and a silicon bond in the organopolysiloxane of the component (B). It is a catalyst for accelerating the formation of cross-links by the addition reaction with elementary-bonded hydrogen atoms and shortening the time required for curing. Examples of the platinum-based catalyst include platinum black and chloroplatinic acid. To dissolve in organopolysiloxane, for example, use a solution such as an alcohol-modified solution of chloroplatinic acid or a silicone-modified solution of chloroplatinic acid. Is preferred. Also,
The amount of the platinum-based catalyst as the component (C) is the amount of catalyst usually used,
For example, about 0.01 to 100 ppm of platinum can be added to the total amount of the components (A) and (B), but when used in an optical fiber, platinum affects optical transmission loss. It is better that the amount of platinum is smaller, specifically, 5 pt as platinum for the total amount of component (A) and component (B).
It is preferably pm or less, and particularly preferably 1 ppm or less.

The organopolysiloxane composition for the core of the optical fiber of the present invention is the above-mentioned component (A), component (B) and (C).
The composition contains components, but when these components are mixed to form a composition, the addition reaction of the components (A) and (B) is caused by the catalytic action of the platinum-based catalyst of the component (C). The reaction proceeds even at around room temperature and the addition reaction proceeds rapidly under heating. Therefore, a reaction inhibitor may be added from the viewpoint of workability. Examples of this reaction inhibitor include acetylene alcohols and 3-methyl-3-butyne-2.
-Ol, 2-methyl-1-pentyl-3-ol, 3,5-
Dimethyl-1-hexyn-3-ol, 2,5-dimethyl-
3-hexyne-2,5-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5-
Examples include decyne-4,7-diol. The amount of the reaction inhibitor added is not particularly limited and may be appropriately selected according to the working conditions.

The composition for a core of the present invention can be manufactured by forming a fiber by a known method such as simply mixing the above components and press-fitting into a tube, and then heating and curing to produce a core of an optical fiber. In this case, the curing conditions are usually 100-150.
It is preferable to heat at 3 ° C. for 3 hours or more.

Although the optical fiber of the present invention is applied as a core, the clad (sheath) component may be made of known plastic. Specifically, as preferable materials for the clad component, for example, polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, polychlorotrifluoroethylene, tetrafluoroethylene / Fluorine-containing polymers such as ethylene copolymer, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene / vinylidene fluoride copolymer, polyamide resin, polyimide resin, polyamideimide resin, epoxy resin, polyvinyl chloride resin, polyester resin Etc. can be mentioned.

〔The invention's effect〕

The silicone-based plastic optical fiber using the cured product of the composition of the present invention in the core does not cause large optical transmission loss even when exposed to high humidity, and stably maintains a high light transmittance with respect to changes in humidity. Therefore, it is possible to expand the range of application of the plastic optical fiber in combination with the original flexibility and heat resistance.

<Examples and Comparative Examples> Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight, Me in the formula represents a methyl group, and Vi represents a vinyl group.

Example 1 The following composition formula (A-1) 100 parts of a resinous vinyl group-containing organopolysiloxane represented by the following formula and the following formula (B-1) 34.2 parts of an organohydrogenpolysiloxane having silicon-bonded hydrogen atoms represented by are mixed, and a 2 wt% octyl alcohol-modified solution of chloroplatinic acid based on the weight of this mixture is added so that the concentration of platinum is 1 ppm. Thus, an organopolysiloxane composition was prepared.

Example 2 The following composition formula (A-2) 100 parts of a resinous vinyl group-containing organopolysiloxane represented by the formula (1) and 34.2 parts of the organohydrogenpolysiloxane represented by the formula (B-1) used in Example 1 were mixed, and the mixture was used on the basis of the weight of the mixture. A 2 wt% octyl alcohol-modified solution of chloroplatinic acid was added as platinum to 1 ppm to prepare an organopolysiloxane composition.

Example 3 The following composition formula (A-3) 100 parts of the resinous vinyl group-containing organopolysiloxane represented by the formula (1) and 29.5 parts of the organohydrogenpolysiloxane represented by the formula (B-1) used in Example 1 were mixed, and the mixture was used on the basis of the weight of the mixture. A 2 wt% octyl alcohol-modified solution of chloroplatinic acid was added as platinum to 1 ppm to prepare an organopolysiloxane composition.

Comparative Example 1 The following composition formula (i) (MeSiO _1.5 ) _0.5 (MeViSiO) _0.25 (Me ₂ SiO) _0.25 ...
(I) 100 parts of a resinous vinyl group-containing organopolysiloxane represented by (i) and 37.3 parts of the organohydrogenpolysiloxane represented by the formula (B-1) used in Example 1 were mixed, and the weight of the mixture was mixed. A 2% by weight octyl alcohol-modified solution of chloroplatinic acid was added as platinum to a concentration of 1 ppm to prepare an organopolysiloxane composition.

[Comparative Example 2] The following composition formula (ii) 100 parts of a resinous vinyl group-containing organopolysiloxane represented by the formula (3) and 30.6 parts of the organohydrogenpolysiloxane represented by the formula (B-1) used in Example 1 were mixed, and the mixture was used on the basis of the weight of the mixture. A 2 wt% octyl alcohol-modified solution of chloroplatinic acid was added as platinum to 1 ppm to prepare an organopolysiloxane composition.

The organopolysiloxane compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were pressed into a fluororesin tube having an inner diameter of 1.5 mm and an outer diameter of 2.2 mm, and heat-cured at 150 ° C. for 3 hours. Then, an optical fiber was produced.

These optical fibers were exposed to a high-humidity environment under the following conditions, and the change in the amount of light before and after that was measured with light of 660 nm.

Condition The optical fiber was exposed to the environment of 60 RH and 90RH% for 100 hours, taken out at room temperature and left for 2 hours, and then the light intensity was measured.

 The results are shown in the table below.

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Claims (2)

(57) [Claims] 1. The following formulas (1) and (2) in the molecule (A) RSiO _1.5 (1) (Provided that R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a is 0, 1 or 2, and b is an integer of 1 to 6). An organopolysiloxane having 0.05 or more alkenyl groups directly bonded to a silicon atom per silicon atom, and (B) an organopolysiloxane having at least two hydrogen atoms directly bonded to a silicon atom in one molecule. And (C) a platinum-based catalyst. 2. An optical fiber having a cured product of the composition according to claim 1 as a core.