JPS5928101A - Optical fiber for transmission - Google Patents

Abstract

PURPOSE:To improve the molding workability and other various characteristics of a coating material for an optical fiber for transmission by using copolymerized polyamide contg. a specified amount of a monomer component having a ring in the principal chain. CONSTITUTION:Copolymerized polyamide contg. 40-80wt% monomer component having a ring in the principal chain is used as a primary and/or secondary coating material for an optical fiber for transmission. Any of monomers of amino acid type and dicarboxylic acid-diamine salt type may be used as the monomer having a ring in the principal chain. The polyamide is easily molded and worked, so a core fiber can be coated efficiently with the polyamide. The polyamide causes a small transmission loss due to a molding strain, etc., can be molded at a low temp., and can minimize an increase in the transmission loss due to external force.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber with excellent transmission characteristics and high mechanical strength.

In order to make an optical fiber cable for normal transmission, consideration is being given to reinforcing the optical fiber core by coating it with plastic or the like.

However, for general plastics, approximately 200
It is extremely difficult for VC to uniformly apply a plastic coating of 100 to 500μ to an optical fiber core of less than μg, and even if the coating is uniform, distortion occurs in the solidification process of the plastic, increasing optical transmission loss. , cannot be put to practical use.

Therefore, plastics having the following properties are useful as coating materials for transmission optical fibers.In the coating process, plastics having the following properties are used to coat optical fibers with a weak mechanical strength of 200 to 500 μy. can be coated with high efficiency. 2) The molding distortion after molding is small and the optical transmission loss is small.

3) The quartz and optical glass materials used in optical fiber cores are subject to oxidative deterioration and chemical deterioration due to moisture, etc. To prevent this deterioration, a certain type of primer is applied to optical fiber cores. , this primer is 200
It should be possible to coat at a low molding temperature, as high temperatures above ℃ can cause thermal decomposition and reduce the performance of the original fiber core.

4) In the process of converging or laying optical fiber cables for transmission, the cable must be flexible and easy to bend;
Good sliding properties, easier connection between cables, and even smaller reduction in optical transmission loss.

5) The heat resistance stability of the superior material (thermal deterioration at high temperatures of 80 to 100 degrees Celsius, thermal cycle deterioration), dimensional stability,
It must have moisture absorption stability, stability in mechanical properties, and stability against long-term changes in transmission loss of the optical 7-eye cable for transmission.

Nylon 12, copolymerized nylon, and mixtures thereof are excellent materials having the above characteristics and are already preferably used. However, as cables that bundle multiple Optical 7 Eyepers are put into practical use, it has become clear that the increase in transmission loss due to external force applied to Optical 7 Eyepers is greater than expected, and the increase in transmission loss due to this external force must be minimized. This has become a serious issue.

It is known that the increase in transmission loss due to external force is caused by microbending of the optical fiber core due to external force. Therefore, in order to prevent this, primary and/or secondary
It is effective to use a hard material with low crystallinity for the subsequent coating. However, generally hard materials do not satisfy any or all of the above characteristics 1 to 5.

The purpose of the present invention is to reduce the transmission loss of the fiber itself.
Another object of the present invention is to provide an optical fiber for transmission in which the increase in transmission loss due to external force is small.

The present inventor has achieved the above by using a copolyamide containing 4o11ttt% to 80w-1h of a polyamide monomer component having a ring in the main chain as the primary and/or secondary pupil of a 7-eyeper optical transmission. I achieved my goal. That is,
This polyamide is easy to mold, can be formed into core wires with high efficiency, has low transmission loss due to molding distortion, can be molded at low temperatures, has good sliding properties, and has excellent long-term properties.
They also found that it has the property of being hard and is particularly suitable for coating optical 7-eye glasses that are subject to external forces.

By copolymerizing a monobu component having a ring in the main chain in an amount of 40 M or more, shrinkage accompanying molding can be reduced and hardness can be obtained. -10,000, ta*W monomer is 80% by weight or less, in other words, the linear monomer having no ring is 20% by weight or less.
Copolymerization of 1 t% or more by weight improves moldability.

As the monomer having a ring in the main chain, either an amino acid form or a salt form of dicarboxylic acid and diamic acid can be used.
Examples of the former include aminobenzoic acid, examples of the latter dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, etc., and examples of diamines include phenylenediamine, isoporo/diamine, bis(p-aminocyclohexyl)methane, etc. I can give an example.

In the salt form of diamine and dicarboxylic acid, either one may have a ring in the main chain, and in that case, the other monomer is a commonly used aliphatic diamine or dicarboxylic acid.

Examples of monomers without a ring in the main chain include nylon 6, nylon 66, nylon 610. nylon 612,
Nylon 11. 3. Optical fibers for transmission coated with a copolymerized polyamide with lower water absorption, which can be exemplified by monomers such as nylon 1 and 2, have excellent long-term characteristics.
For this purpose, a nylon 11 or nylon 12 monomer is most preferably used as a monomer having no ring in its main chain.

Examples and comparative examples will be described below.

Example 1. Comparative Example 1.2゜lauryllactam 34% by weight, isophthalic acid 31% by weight
%, isophoronediamine 16% by weight, bis(p-aminocyclohexyl)methane 19% by weight, 1% copolyamide.
1, a 40 mm extruder with a draw-down die, fully extruded, with an outer diameter of 15 mm with a primary coating of thermosetting polyurethane.
A secondary coating was applied on a 0μ multimode grated glass fiber core (transmission loss 2.cziB/Km).1 Transmission by optical disappearance of the thus obtained optical fiber with a wavelength of 0.84μ I checked the loss 1. Also, I sandwiched this optical fiber between 80 grit sandpaper and
The transmission loss under external force with a similar wavelength was investigated by applying a load of k(l).

On the other hand, similar experiments were conducted on nylon 12, 80:20 copolymer-2 of lauryllactam and caprolactam, and the results are shown in Table-1.

Patent Applicant Daicel Kaji Kogyo Co., Ltd. Procedural Amendment (Method) % Formula % 1. Indication of Case 1982 Patent Application No. 137760
No. 2, Title of the invention Transmission optical fiber 3, Relationship with the case of the person making the amendment Patent applicant 4, Date of amendment order November 30, 1980 (shipment date) 5, Subject of amendment Full text of the specification 6, Amendment Contents As shown in the attached sheet (no changes to the contents)

Claims (1)

[Claims] An optical fiber for transmission, characterized in that a copolymerized polyamide containing 40% by weight or more and 80% by weight or less of a polyamide monomer component having a ring in the main chain is used as the primary and/or secondary coating material of the optical fiber for transmission. .