JPH01224703A - Plastic clad quartz optical fiber - Google Patents

Abstract

PURPOSE:To improve the bonding property of the glass of a core material and a sheath material by using a fluorinated polymer added with a compd. having an active silyl group as a polymer for the sheath material. CONSTITUTION:The polymer obtd. from a compd. having a fluorinated alkyl group and (meth)acrylic group, polyfunctional monomer, photopolymn. initiator and polymerizable carbon-carbon unsatd. bond and the compd. having the active sylyl group is used as the sheath material. The compd. having the polymerizable carbon-carbon unsatd. bond and the active silyl group is preferably the compd. expressed by formula I. In formula R1 is a hydrogen atom., fluorine atom. or methyl group; R2 denotes a methyl group, ethyl group, propyl group or methoxy ethyl group; (n) denotes >=3 integer. The active silyl group has the excellent bonding property to glass surface which is the core material and contributes to an improvement in the boundary face between the sheath material and the core material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel plastic-clad quartz optical fiber.

Plastic clad quartz optical fibers using quartz glass or optical glass as a core material and dimethyl silicone resin as a sheath material are known.

This plastic-clad quartz optical fiber using dimethyl silicone resin as a sheath material has the disadvantage that the core fiber protrudes from one end face of the optical fiber as the temperature changes in the environment in which it is used, and the optical transmission performance fluctuates significantly.

Furthermore, the dimethyl silicone resin used as the sheath material is generally soft and has insufficient adhesion to the quartz glass core material, making it difficult to attach the connector to the fiber end. In other words, it is impossible to use a crimp connector, and the sheath material must be stripped off, a portion of the core glass fiber is attached to the connector with adhesive, and then the cross section must be polished.

These problems greatly limit the use of plastic-clad quartz optical fibers.

The present inventors completed the present invention as a result of conducting research to solve the above problems.

The present invention is a plastic clad quartz optical fiber using (a) a compound having a fluorinated alkyl group and a (meth)acrylic group, and (b) a polyfunctional monomer and a polymer as a sheath material.

In the present invention, in place of the conventional dimethyl silicone resin as the polymer for the sheath material, a fluorinated polymer to which a compound having an active silyl group is added is used, thereby improving the bond between the glass of the core material and the sheath material. It is something that makes you As a result, it becomes possible to use the crimp connector with the sheath material still attached, and the workability in using optical fibers can be greatly improved. In addition, it is possible to prevent deterioration in optical transmission performance and protrusion of the core material at one end face of the fiber caused by temperature changes.

Examples of the compound (a) having a fluorinated alkyl group and a (meth)acrylic group used in the present invention include the following compounds. Trifluoroethyl (meth)acrylate, 2,2,3.3-tetrafluoropropyl (
meth)acrylate, 2.2,3,3.3-pentafluoropropyl (meth)acrylate, 2-trifluoromethyl-6,3゜6-trifluoropropyl (meth)acrylate, 2-trifluoromethyl-2, 3, 3, 3
-Tetrafluoropropyl (meth)acrylate, 2゜2.3,4,4.4-hexafluorobutyl (meth)acrylate, 1-methyl-2,2,3,4,4,4-hexafluorobutyl (meth)acrylate, 1,1゜2
．． 2-tetrahydroperfluorododecyl (meth)acrylate, 1,1,2.2-tetrahydro-9-trifluoromethylperfluorodecyl (meth)acrylate, 1,1-dihydroperfluorobutyl (meth)acrylate, 1,1 -dimethyl-2,2,3,3-tetrafluoropropyl (meth)acrylate, 1,1-dimethyl-2,2,,5,5,4,.

4.5.5-octafluoropentyl (meth)acrylate, 1,1-dimethyl-2,2,5,4,4,4-hexafluorobutyl (meth)acrylate, etc.

These polymers can also be used.

(b) Examples of the polyfunctional monomer include the following compounds. 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanethiol di(meth)acrylate, diethylene glycol di(meth)acrylate, neobentyl glycol di( meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. These polyfunctional monomers may be used alone or in a mixture of two or more.

The photopolymerization initiator (c) used in the present invention may be one used as a photopolymerization initiator or sensitizer in ultraviolet curable dyes, and examples thereof include the following compounds. Benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin butyl ether, 2
- Methylhentuin, benzophenone, Michler's ketone, benzyl, benzyl dimethyl ketal, benzyl diethyl ketal, anthraquinone, methyl anthraquinone, diacetal, acetophenone, diphenyl disulfide, anthracene, etc., as well as mixtures of these with small amounts of sensitizers, such as amines.

(d) Compounds having a polymerizable carbon-carbon unsaturated bond and an active silyl group include the general formula (wherein R1 is a hydrogen atom, a fluorine atom, or a methyl group, and R2 is a methyl group, an ethyl group,
A compound represented by a propyl group or a methoxyethyl group (n is an integer of 6 or more) is preferred. Examples include the following compounds. 3-(meth)acryloxypropyltrimethoxysilane, 6-(meth)acryloxypropyltris(methoxyethoxy)silane, 3-(meth)acryloxyglobylmethyldiethoxysilane, 3-(meth)acryloxypropyldimethyl Ethoxysilane, 3
-(meth)acryloxypropyldimethylethoxysilane, N-(3-(meth)acryloxy-2-hydroxypropyl]6-amituprobyltriethoxysilane, etc.

These (co)polymers can also be used.

Since these compounds have a polymerizable group such as an acrylic group or a methacryloxy group in the molecule, (
Active silyl groups can be introduced into the sheath material by forming a copolymer with a) a compound having a fluorinated alkyl group and a (meth)acrylic group or fb) a polyfunctional monomer. The active silyl group has excellent bonding properties with the glass surface of the core material, making it possible to obtain a plastic-clad quartz optical fiber with improved adhesion at the interface between the sheath material and the core material.

In manufacturing the plastic-clad quartz optical fiber of the present invention, first a sheath material composition containing components a% d is prepared.

The content of each component in the sheath material composition is 60 to 90 parts by weight of component a and components b1 to 7 with respect to 100 parts by weight of the sheath material composition.
0 parts by weight is preferred. The content of component d is preferably 0.1 to 60 parts by weight based on 100 parts by weight of the sheath material composition. If the content is less than 0.1 part by weight, the effect of improving adhesion will be insufficient, and if the content is more than 30 parts by weight, the transparency and storage stability of the sheath material composition will decrease.

Furthermore, an oligomer or polymer having good compatibility with the sheath material composition can be added to the sheath material composition used in the present invention for the purpose of adjusting the viscosity of the composition. As these oligomers and polymers, fluorinated oligomers or fluorinated polymers containing fluorine atoms are preferred.

Next, the quartz core fiber is coated with the sheath material composition and then photopolymerized to obtain the desired optical fiber.

As a method for coating the quartz core fiber, for example, a method of applying a sheath material composition, a method of dipping the quartz core fiber in a sheath material composition, etc. are used. Photopolymerization can be carried out, for example, by irradiating with ultraviolet rays.

Test Example 1 50 parts by weight of trifluoroethyl acrylate, 2.2,
3.10 parts by weight of 6-titrafluorobrobyl acrylate, 7 parts by weight of trimethylolpropane triacrylate, 60 parts by weight of trifluoroethyl methacrylate polymer, 3 parts by weight of benzyl dimethyl ketal (manufactured by Ciba Geigy, Irgacure 651) as a photopolymerization initiator Part and 3
- Mixing 2 parts by weight of methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM 503),
A uniform photopolymerizable sheath material composition was obtained by thorough stirring. Next, this photopolymerizable sheath material composition was spread on a glass plate to a thickness of 50 μm.
A sample was prepared by casting the sample onto a polyester film and closely covering it with a polyester film. When this sample was irradiated with ultraviolet rays for about 10 seconds from a high-pressure mercury lamp with an output of 80 w/cm, a uniform and transparent cured film was obtained. This cured film was peeled from the glass plate in a 90° direction, and the peel strength at that time was measured and found to be 2609/CrIK.

Comparative Test Example 6 - A cured film was prepared in the same manner as in Test Example 1 except that a sheath material composition containing no methacryloxypropyltrimethoxysilane was used.

The peel strength of this cured film from a glass plate was measured and was as low as 5 g/Cm.

Example After applying the photopolymerizable sheath material composition prepared in Test Example 1 to the surface of a quartz core fiber with a diameter of 200 μm, the photopolymerizable sheath material composition was polymerized using an ultraviolet irradiation device with a built-in high-pressure mercury lamp. As a result, a polymer-clad quartz optical fiber having an outer diameter of 250 μm was obtained. 8 of this optical fiber
The transmission loss at a wavelength of 50 μm was 5 dB/km, indicating good transmission performance. This optical fiber
When a heat cycle was performed with a temperature change of 0 to +70°C, the change in transmission performance was as good as ±1 dB/km or less, and no protrusion of the core fiber from one end surface of the optical fiber occurred.

Test Examples 2 to 4 Using the following photopolymerizable sheath material compositions, cured films were prepared in the same manner as in Test Example 1, and the peel strength from the glass plate was measured. The results are also shown in the table. The copolymers in the table were produced by the following method.

Production of methyl methacrylate/6-methacrylokidiglobil trimethoxysilane copolymer: 90 g of methyl methacrylate in 150 g of thoroughly purified and dried toluene,
10g of 3-methacryloxypropyltrimethoxysilane
and 0.2 g of azobisisobutyronitrile were added and mixed well. This mixture was mixed into a 6QQm with a cooling tube and a stirrer.
The mixture was placed in a flask, the atmosphere was purged with dry nitrogen gas, and the mixture was heated to 75°C without stirring. Stirring and heating were continued for 4 hours to complete polymerization, and then the mixture was poured into methanol to separate the polymer. The polymer thus obtained was dried at room temperature.

Claims (1)

[Claims] 1. (a) a compound having a fluorinated alkyl group and a (meth)acrylic group, (b) a polyfunctional monomer, (c) a photopolymerization initiator, and (d) a polymerizable carbon- A plastic clad quartz optical fiber whose sheath material is a polymer obtained from a compound having carbon unsaturated bonds and active silyl groups. 2. Compounds with polymerizable carbon-carbon unsaturated bonds and active silyl groups have general formulas ▲mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 is a hydrogen atom, a fluorine atom, or a methyl group, R_
2. The plastic-clad quartz optical fiber according to claim 1, wherein 2 is a methyl group, ethyl group, propyl group, or methoxyethyl group, and n is an integer of 3 or more.