JPH0756026A - Production of plastic member for light transmission - Google Patents

Abstract

PURPOSE:To provide a process for production of the plastic member for light transmission which has a desired refractive index change, is easily produced and is inexpensive. CONSTITUTION:This plastic member is constituted by molding a circular cylinder 10 consisting of a polymer A having a photoreactive active group and diffusing a compd. C, which is formed by reaction with the polymer A and of which the refractive index (Nb) of the resulted product B thereof is lower than the refractive index (Na) of the polymer A from the outer periphery to the inside of the circular cylinder 10 by using a diffusion soln. 12 of this compd. C to form a concn. distribution in which the concn. of the compd. C decreases gradually from the outer peripheral part of the cylinder toward the center. The circular cylinder is thereafter irradiated with UV light capable of bringing the photoreactive active group of the polymer A into reaction, by which a photoreaction is effected and the product B is fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical transmission plastic member used for optical communication.

[0002]

2. Description of the Related Art An optical fiber having both a core and a clad made of plastic is used as a short-distance optical transmission line in which transmission loss is not a problem between electronic devices for transmitting and receiving optical signals. Since it is easier to use and cheaper than glass fiber, it is widely used and is particularly important in the concept of next-generation communication networks such as LAN and ISDN.

Conventionally, as shown in FIG. 3, in the plastic optical fiber 01, PMMA (polymethylmethacrylate resin), PC (polycarbonate resin) or a copolymer resin of these is used for the core 02, and the cladding 0
A step index (SI) type optical fiber having a refractive index distribution as shown in FIG.

Further, a great index (GI) type optical fiber having a refractive index distribution as shown in FIG. 3C, which can send a large amount of information per time to this SI type optical fiber, is, for example, a special one. It is disclosed in various publications such as JP-B-52-5857, JP-B-54-30301, JP-A-61-130904 and JP-B-61-130904, but there are various problems from the viewpoint of manufacturing. , I haven't got what I want.

On the other hand, the applicant of the present invention also has a plastic optical fiber plug whose refractive index changes continuously by repeatedly injecting two kinds of materials having different refractive indexes into a cylinder and polymerizing and laminating the materials under centrifugal force. Although a method for manufacturing a reform has been previously proposed (see Japanese Patent Laid-Open No. 60-119509), it takes time to manage the refractive index according to a desired design value,
There is a problem that it cannot be manufactured at a low price.

In view of the above problems, it is an object of the present invention to provide a method of manufacturing a plastic member for optical transmission which has a desired change in refractive index and is simple and inexpensive to manufacture.

[0007]

A first method for producing a plastic member for optical transmission according to the present invention, which achieves the above object, is a columnar body or a linear body made of a polymer A having a photoreactive active group. A columnar body or a linear body using a compound C which is formed by reacting with the polymer A and has a refractive index (Nb) of the product B lower than that of the polymer A (Na). The compound C is diffused from the outer periphery to the inner part of the polymer to form a concentration distribution in which the concentration of the compound C is gradually reduced from the outer periphery to the center, and then the photoreactive active group of the polymer A is reacted from the outside. It is characterized in that the product B is fixed by irradiating light capable of causing the photoreaction.

In the second production method, the polymer A having a photoreactive active group is reacted with the polymer A and the product D has a refractive index (Nd) of the polymer A. And a compound E having a refractive index (Na) higher than that of the above, a columnar body or a linear body is molded, and then the compound E is volatilized from the outer periphery of the columnar body or the linear body, and a center is formed from the outer periphery. To form a concentration distribution in which the concentration of the compound E is gradually reduced, and then to externally irradiate light capable of reacting the photoreactive active group of the polymer A to cause a photoreaction to fix the product D. Is characterized by.

In the third production method, the polymer A having a photoreactive active group is reacted with the polymer A, and the product D has a refractive index (Nd) of the polymer A. And a compound E having a refractive index (Na) higher than that of the above, a columnar body or a linear body is molded, and then the compound E is volatilized from the outer periphery of the columnar body or the linear body, and a center is formed from the outer periphery. To form a concentration distribution in which the concentration of the compound E is gradually decreased, or after that, the reaction is performed with the polymer A, and the refractive index (Nb) of the product B is the refractive index of the polymer A ( Using a compound C which is lower than Na),
The compound C is diffused from the outer periphery of the columnar body or the linear body to the inside thereof, and thereafter, light capable of reacting the photoreactive active group of the polymer A is irradiated from the outside to cause a photoreaction,
It is characterized in that the product is fixed.

Further, in the above manufacturing, the cylindrical body is a plastic optical fiber preform, and the linear body is a plastic optical fiber.

Further, in the above production, the cylindrical body is the preform for the plastic optical fiber, and the preform for the optical fiber is heated and melted and drawn into the optical fiber, and then the photoreaction of the compound A is performed. Characterize.

The contents of the present invention will be described below.

Here, the polymer A having a photoreactive active group in the present invention is a compound in which the active groups react with each other by irradiation with light having heat energy such as ultraviolet rays and chemically bond with each other. And the side chain has, for example, α / β- such as cinnamic acid residue.
A polymer or copolymer containing an unsaturated carbonyl group.
Specifically, ethylene-P-vinyl ethyl cinnamate containing a cinnamic acid residue (refractive index: Na = 1.525) can be exemplified.

The product B obtained by reacting with the above polymer A
The compound C having a lower refractive index (Nb) than the refractive index (Na) of the polymer A means cinnamic acid trifluoroethyl ester (when the polymer A is an ethylene-vinyl cinnamate copolymer). Refractive index: Nc = 1.485) can be exemplified.

Next, an example of manufacturing a plastic optical fiber preform will be described with reference to FIG.

FIG. 1 is a schematic view of a coating apparatus used in the method of the present invention. In the figure, reference numeral 10 is a cylindrical body, 11 is a dipping tank, and 12 is a diffusion solution.

In the first production method of the present invention, the polymer A having a photoreactive active group is shaped into a cylindrical columnar body 10,
Next, the columnar body 10 is immersed in an immersion tank 11 containing a compound C as a diffusion solution 12 (see FIG. 1).
(See (A)). After soaking under a predetermined condition, the columnar body 10 is pulled up, and while the columnar body 10 is rotated, ultraviolet rays (UV) are irradiated from the outside (see FIGS. 1B and 1C). As a result, a plastic optical fiber preform having a refractive index distribution in which the refractive index gradually decreases from the center to the outside along the concentration distribution of the compound C is obtained. In addition to the above-mentioned dipping-type application, for example, a brush application using a brush may be similarly performed.

FIG. 2A shows the plastic optical fiber preform 13 thus obtained, and FIG. 2B shows its GI type refractive index profile.

The optical fiber preform obtained as described above is subjected to a normal drawing operation, for example, holding the optical fiber preform in a vertical state and heating and melting it to obtain a desired plastic optical fiber.

In the above-mentioned method, an optical fiber is manufactured by forming a desired optical fiber preform and then drawing the optical fiber. However, the present invention is not limited to this, and the polymer A is used instead of the cylindrical body. After forming a predetermined linear body on the above, the above-mentioned operation may be performed in the same manner. At that time, in order to cause a photoreaction, it is sufficient to irradiate the ultraviolet rays while winding the linear body.

In the first production method described above, the compound C is impregnated into the columnar body or linear body made of the polymer A. In addition to such an operation, the second method is used. As a method for producing the above, a compound E which is produced by reacting with the polymer A and the product D of which is higher than the refractive index (Na) of the polymer A is used. First, from the polymer A and the compound E,
Form a cylindrical body or a linear body. Then, the compound E is volatilized from the molded body to obtain a concentration distribution in which the concentration of the compound E is gradually reduced from the center to the outer peripheral portion, and thereafter, by irradiating light from the outside, the compound E is continuously formed in a form along the concentration distribution. The product D formed by the reaction between the polymer A and the compound E may be fixed to a columnar body or a linear body by forming the above refractive index distribution.

Here, as the compound E, when the polymer A is an ethylene-vinyl cinnamate copolymer having a cinnamic acid residue (refractive index: Na = 1.525), for example, cinnamic acid ethyl ester is exemplified. be able to.

Further, as the third manufacturing method, the above-mentioned 2
Method in which two kinds of methods are used in combination, that is, the compound E forms a continuous concentration distribution from the center to the outer peripheral portion by the second method, and at the same time or after that, the compound C is formed by using the compound C by the first method. It is also possible to obtain a columnar body or a linear body in which the concentration distribution of the reaction product is changed by gradually diffusing it to the outside and then gradually changing the refractive index from the center to the outer periphery. .

The chemical formulas of the above-mentioned polymer A and its specific examples, product B, compound C, product D and compound E are shown in the following "Chemical formula 1" to "Chemical formula 6", respectively.

[0025]

[Chemical 1]

[0026]

[Chemical 2]

[0027]

[Chemical 3]

[0028]

[Chemical 4]

[0029]

[Chemical 5]

[0030]

[Chemical 6]

[0031]

The preferred embodiments of the present invention will be described below.

(Embodiment 1) Embodiment 1 will be described with reference to FIG. Ethylene containing 1 mol% of cinnamic acid residue
Ethyl P-vinyl cinnamate (Polymer A, Na = 1.525)
Is kneaded by heating to 100 ° C. and extruded to give a diameter of 1
A cylindrical body 10 having a length of 0 mm and a length of 300 mm was obtained. The cylindrical body 10
As a diffusion solution 12 in a liquid of cinnamic acid trifluoroethyl ester (compound C; Nc = 1.485) at 70 ° C.,
It was immersed for about 4 hours, and was made to be in a state of being impregnated with the ester except for the central portion of the columnar body 10 (see FIG. 1B). Next, while rotating the cylindrical body after impregnation, from the outer peripheral portion,
Ultraviolet irradiation was carried out for about 20 minutes using an ultraviolet lamp (1 kw mercury lamp) to chemically bond the cinnamic acid residue and the ester by a photodimerization reaction to obtain a plastic optical fiber preform 13 (Fig. 1). (See (C)). When the optical fiber preform 13 was measured by an interference microscope (manufactured by Mizojiri Co., Ltd.),
The refractive index in the central part is n _D = 1.523, and the refractive index in the peripheral part is n _D = 1.
497, and the distribution was a GI type refractive index distribution (see FIGS. 2A and 2B).

(Example 2) Ethyl ethylene-P-vinyl cinnamate containing 1 mol% of cinnamic acid residue (polymer A, Na = 1.
525) was kneaded by heating at 100 ° C. and extruded to obtain a linear body having a diameter of 500 μm and a length of 300 m. The linear body was immersed in a liquid of cinnamic acid trifluoroethyl ester (compound C; Nc = 1.485) at 40 ° C. for about 5 minutes, and the ester was impregnated except the central portion of the linear body. I was in a state of doing. Next, while winding the impregnated linear body at a linear velocity of 50 m / min, an ultraviolet lamp (1 kw
It was irradiated with ultraviolet rays using a mercury lamp) to chemically bond the cinnamic acid residue and the ester by a photodimerization reaction to obtain a plastic optical fiber. When this optical fiber was measured by an interference microscope (manufactured by Mizojiri Co., Ltd.), the refractive index at the central portion was n _D = 1.53, and the peripheral portion was n _D = 1.50, and its distribution was a GI type refractive index. It was a distribution.

Example 3 Ethyl ethylene-P-vinyl cinnamate containing 1 mol% cinnamic acid residue (polymer A, Na = 1.
525) 85 parts by weight and 15 parts by weight of cinnamic acid ethyl ester (compound E) were kneaded by heating at 100 ° C. and extruded to obtain a cylindrical body having a diameter of 10 mm and a length of 300 mm.
The cylinder is dried under reduced pressure of 5 mmHg at 50 ° C. for 1 hour,
The cinnamic acid ethyl ester in the column was partially volatilized.
Next, while the columnar body after volatilization was rotated, ultraviolet rays were irradiated from its outer peripheral portion for about 20 minutes using an ultraviolet lamp (1 kw mercury lamp), and the cinnamic acid residue and the ester were subjected to a photodimerization reaction. It was chemically bonded to obtain a plastic optical fiber preform. When this optical fiber preform was measured with an interference microscope (Mizojiri Co., Ltd.), the refractive index at the center was n _D.
= 1.562, the peripheral part had n _D = 1.525, and the distribution was a GI type refractive index distribution.

Example 4 Ethyl ethylene-P-vinyl cinnamate containing 1 mol% cinnamic acid residue (polymer A, Na = 1.
525) 85 parts by weight and 15 parts by weight of cinnamic acid ethyl ester (compound E) were kneaded by heating at 100 ° C. and extruded to obtain a linear body having a diameter of 500 μm × a length of 300 m. The linear body was dried under reduced pressure of 25 mmHg at 50 ° C. for 10 minutes to partially volatilize cinnamic acid ethyl ester in the linear body. Next, while winding the volatilized linear body at a linear velocity of 50 m / min, the peripheral portion thereof was irradiated with ultraviolet rays using an ultraviolet lamp (1 kw mercury lamp) to remove the cinnamic acid residue and the ester. A plastic optical fiber was obtained by chemically bonding by a photodimerization reaction. When this optical fiber was measured by an interference microscope (manufactured by Mizojiri Co., Ltd.), the refractive index in the central part was n _D = 1.56, and the peripheral part was n _D = 1.53, and its distribution was a GI type refractive index. It was a distribution.

Example 5 Ethyl ethylene-P-vinyl cinnamate containing 1 mol% cinnamic acid residue (Polymer A, Na = 1.
525) 85 parts by weight and 15 parts by weight of cinnamic acid ethyl ester (compound E) were kneaded by heating at 100 ° C. and extruded to obtain a cylindrical body having a diameter of 10 mm and a length of 300 mm.
The columnar body was immersed in a liquid of cinnamic acid trifluoroethyl ester (Compound C; Nc = 1.485) at 70 ° C. for about 1 hour to partially replace the columnar ester with fluoroethyl ester. did. Next, while rotating the columnar body after the substitution, ultraviolet rays are irradiated from its outer peripheral portion for about 20 minutes using an ultraviolet lamp (1 kw mercury lamp), and the cinnamic acid residue, the ester and the fluoroester are exposed to light. It was chemically bound by a dimerization reaction to obtain a plastic optical fiber preform. When this optical fiber preform was measured with an interference microscope (Mizojiri Co., Ltd.), the refractive index at the center was n _D = 1.56.
3, n _D = 1.499 in the peripheral portion, and the distribution was a GI type refractive index distribution.

Example 6 Ethyl ethylene-P-vinyl cinnamate containing 1 mol% cinnamic acid residue (polymer A, Na = 1.
525) 85 parts by weight and 15 parts by weight of cinnamic acid ethyl ester (compound E) were kneaded by heating at 100 ° C. and extruded to obtain a linear body having a diameter of 500 μm × a length of 300 m. Approximately 3 parts of the linear compound was added to cinnamic acid trifluoroethyl ester (compound C; Nc = 1.485) at 40 ° C.
Dipping for a minute allowed the ester of the linear to partially replace the fluoroethyl ester. Next, while winding the substituted linear body at a linear velocity of 50 m / min, the peripheral portion of the linear body was irradiated with ultraviolet rays using an ultraviolet lamp (1 kw mercury lamp) to obtain the cinnamic acid residue, the ester, and the ester. Fluoroester and light 2
It was chemically bound by a quantification reaction to obtain a plastic optical fiber. This optical fiber is an interference microscope (Mizojiri)
The refractive index in the central part was measured as follows: n _D = 1.5
6, n _D = 1.50 in the peripheral portion, and its distribution was a GI type refractive index distribution.

[0038]

As described above with reference to the embodiments, according to the present invention, it is possible to control the refractive index distribution, which is extremely difficult by the conventional method, by an easy and simple method, and a uniform GI type plastic optical material. A fiber preform can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the method of the present invention.

FIG. 2 is a plastic base material and its refractive index distribution chart.

FIG. 3A is a schematic view of a plastic base material,
(B) is a SI type refractive index profile and (C) is a GI type refractive index profile.

[Explanation of symbols]

 10 Cylindrical body 11 Immersion tank 12 Solution 13 Optical fiber base material

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroo Matsuda 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works

Claims (5)

[Claims] 1. A cylindrical body or a linear body made of a polymer A having a photoreactive active group is molded and reacted with the polymer A, and the product B has a refractive index (Nb) of Using the compound C having a refractive index (Na) lower than that of the polymer A, the compound C is diffused from the outer circumference to the inside of the cylindrical body or the linear body, and the concentration of the compound C gradually increases from the outer circumference to the center. A plastic member for optical transmission, characterized by forming a reduced concentration distribution, and then irradiating light capable of reacting the photoreactive active group of the polymer A from the outside to cause a photoreaction to fix the product. Manufacturing method. 2. A polymer A having a photoreactive active group,
A columnar body or a linear body is formed by using the compound E which reacts with the polymer A and has a refractive index (Nd) of the product D higher than the refractive index (Na) of the polymer A. Then, the compound E is volatilized from the outer periphery of the columnar body or the linear body to form a concentration distribution in which the concentration of the compound E is gradually reduced from the outer periphery to the center, and then the light of the polymer A is externally applied. A method for producing a plastic member for optical transmission, which comprises irradiating light capable of reacting a reactive active group to cause photoreaction to fix the product. 3. A polymer A having a photoreactive active group,
A columnar body or a linear body is formed by using the compound E which reacts with the polymer A and has a refractive index (Nd) of the product D higher than the refractive index (Na) of the polymer A. Then, the compound E is volatilized from the outer periphery of the columnar body or the linear body to form a concentration distribution in which the concentration of the compound E gradually decreases from the outer periphery to the center, or after that, the polymer A And the product B has a refractive index (Nb) of the polymer A.
By using the compound C which becomes lower, the compound C is diffused from the outer periphery of the columnar body or the linear body to the inside thereof, and thereafter, a light capable of reacting the photoreactive active group of the polymer A is irradiated from the outside. A method for producing a plastic member for optical transmission, characterized in that the product is fixed by photoreacting with light. 4. The method for manufacturing a plastic member for optical transmission according to claim 1, wherein the cylindrical body is a base material for a plastic optical fiber, and the linear body is a plastic optical fiber. 5. The compound A according to claim 1, wherein the cylindrical body is a plastic optical fiber preform, and the optical fiber preform is heated and melted and drawn into an optical fiber.
A method for producing a plastic member for optical transmission, which comprises performing the photoreaction of