JPH0381704A - Production of plastic optical transmission body - Google Patents

Abstract

PURPOSE:To obtain a continuous refractive index distribution by molding a mixture composed of a monomer A and a polymer B to a fiber shape, then diffusing a monomer C which forms a polymer of low refractive index into the fiber from the outer peripheral part thereof after the polymerization of a part of the monomer A. CONSTITUTION:The mixture 1 composed of the monomer A and the polymer B is inserted into a cylinder 3 and is extruded from a nozzle 4 by a piston 2 and is thereby molded to a fiber shape; thereafter, the monomer A is partly polymerized in a part 5 for irradiation with active rays. The monomer C which has the refractive index lower than the refractive index of the polymer of the monomer A after polymn. is diffused into the fiber from the outer peripheral part thereof in a diffusing chamber 6 to form the concn. distribution of the monomers A and C from the center toward the outer periphery. The monomers are then polymerized in a part 7 for irradiation with active rays to obtain the optical transmission body 9. The optical transmission body having the continuous refractive index distribution is obtd. in this way.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a plastic optical transmission device having a continuous refractive index distribution from the center to the outer periphery, which is used in a light-focusing lens, a light-focusing fiber, etc. The present invention relates to a method of manufacturing a body.

[Conventional technology and issues to be solved! ! ! ] As an optical transmission body having a continuous refractive index distribution from the center to the outer periphery, a glass one has already been proposed in Japanese Patent Publication No. 47-816.

However, glass optical transmission bodies have low productivity and
It has the problems of being expensive and having poor flexibility.

Several methods have been proposed for manufacturing a plastic optical transmission body in contrast to such a glass optical transmission body. The manufacturing methods of plastic optical transmitters having a continuous refractive index distribution from the center to the outer periphery can be roughly divided into (
]) A synthetic resin body made of an ionically crosslinked polymer in which the concentration of metal ions changes continuously from the central axis toward the surface (Japanese Patent Publication No. 47-26913);
(2) A synthetic resin body manufactured from a mixture of two or more transparent polymers having different refractive indexes is treated with a specific solvent to partially dissolve and remove at least one of the structural components of the synthetic resin body. Products manufactured by
No. 8059) (3) Two types of monomers with different refractive indexes,
The polymerization method is devised to create a continuous refractive index distribution from the surface to the inside (Special Publication Publication No. 54-303).
01), (4) Diffuse a monomer with a lower refractive index than the surface of the crosslinked polymer, arrange it so that the content of this monomer changes continuously from the surface to the inside, and then polymerize to increase the refractive index. Those with distribution (Special Publications 52-5
No. 857, Special Publication No. 56-37521), and (5)
A low-molecular compound having a refractive index lower than that of the polymer is diffused and reacted with the surface of a reactive polymer to create a continuous refractive index distribution from the surface to the inside (Japanese Patent Publication No. 1983- No. 29682), etc.

A common problem with these conventional methods is that processes such as diffusion and extraction take a long time and are limited in length, so the production process is intermittent, in other words, it is a batch production method. These manufacturing methods each have their own problems as an industrial technology, such as extremely low productivity, extremely difficult selection of manufacturing conditions, and inability to achieve reproducibility.

[Means for Solving the Problems] The present invention solves the irrationality caused by the intermittent production process of the above-mentioned conventional technology, and enables continuous production similar to glass or plastic optical fibers. This prevents the rapid volatilization of the monomer from the surface of the fibrous excipient from the mixture of polymer and monomer, and uniformly diffuses the low refractive index monomer into the fibrous material. The present invention was developed as a result of studies aimed at obtaining an optical transmission body that always has a uniform refractive index distribution.

That is, the gist of the present invention is to form a mixture of monomer (A) and polymer (B) into a fiber shape, and to form the mixture of monomer (A) and polymer (B) into a fiber.
A monomer (C) that becomes a polymer with a refractive index lower than that of the polymer of monomer (A) after polymerizing a part of A).
is diffused from the outer periphery of the fiber to shape the concentration distribution of monomer (A) and monomer (C), and then the unpolymerized monomer is polymerized, which is continuous from the center to the outer periphery. The present invention relates to a method for manufacturing a plastic optical transmission body having a refractive index distribution.

An example of the manufacturing method of the present invention is shown in FIG. 1.

A mixture (1) of monomer (A) and polymer (B) is inserted into a cylinder (3), and a piston (2) is used to introduce the mixture (1) into a nozzle (4).
) and shaped into a fiber, a part of the monomer (A) is polymerized in the actinic ray irradiation section (5).
Next, monomer (C), which has a lower refractive index after polymerization than the polymer of monomer (A), is diffused from the outer periphery of the fiber in a diffusion tank (6), and the monomer is dispersed from the center to the outer periphery. (A
) and the monomer (C), polymerize in the actinic ray irradiation section (7), and continuously obtain the desired light transmitting body (9) with the nip rollers (8).

At this time, it is desirable to introduce a gas such as nitrogen or argon gas into the irradiation section in order to facilitate polymerization by actinic rays.Also, the polymerization rate of monomer (A) can be controlled by the actinic ray irradiation section ( It can be performed using the irradiation time shown in 5).

Next, the present invention will be explained in detail with reference to Examples.

As the monomer (A) and monomer (C) used in carrying out the present invention, monomers that can provide polymers with various refractive indexes can be used, including methyl (meth)acrylate,
Ethyl (meth)acrylate, butyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, cyclohexyl (meth)acrylate, adamantyl (meth)acrylate, perfluoroalkyl (meth)acrylate, perfluorodimethyldioxole , perfluoroalkyl vinyl ether, styrene, α-methylstyrene, etc.
A good combination of these monomers is such that the refractive index of the polymer obtained from monomer (A) is greater than the refractive index of the polymer obtained from monomer (C). This is a necessary condition to obtain an optical transmission body with a refractive index distribution.

As the polymer (B) used in carrying out the present invention, any polymer can be used as long as it has good compatibility with the monomer (A) and the monomer (C). For example, methyl Methacrylate polymers, styrene polymers, polycarbonates, poly4-methylpentene-1, and homopolymers or copolymers of monomers (A) and monomers (C) can be used. Coalescence is essential for improving the shapeability of the filamentary optical transmission body of the present invention and for improving the refractive index distribution and sharpness.

In the present invention, it is necessary that the refractive index of the monomer (C) after polymerization is smaller than the refractive index of the polymer made from the monomer (A), and if this condition is not satisfied, It is not possible to obtain an optical transmission body having a refractive index distribution with desired characteristics.

The present invention has the great advantage that it is possible to always produce an optical transmission body with extremely excellent uniformity and a desired refractive index distribution.

[Example] Example 1 Methyl methacrylate (polymer n-1,489) 5
0 parts by weight, polymethyl methacrylate ([η]-0,3
6 (MEK, 25°C)) A mixture of 50 parts by weight of 1-hydroxycyclohexylphenyl ketone and 1 part by weight of 1-hydroxycyclohexylphenyl ketone was uniformly mixed and inserted into the l cylinder (3) shown in Fig. 1, and then inserted into the piston (2). The cylinder temperature at this time was 70°C.

Next, N at 50℃! Gas is 54! /sin to the active light irradiation part (5), and chemical rough 1 at 20-
Eight fibers were irradiated with ultraviolet light for 30 seconds and photopolymerized to obtain a fiber with a monomer (methyl methacrylate) polymerization rate of 50%. The obtained fiber is guided to a diffusion tank (6), and 2.2.
3. Diffuse 3-tetrafluoropropyl methacrylate from the outer periphery of the fiber. The liquid temperature at that time was 40℃
The contact diffusion time between the fiber and 2.2.3.3-tetrafluoropropyl methacrylate was 30 seconds.

Next, N8 gas at 50°C was 54! In the actinic ray irradiation section (7) running at /win, ultraviolet rays were irradiated for 1 minute using three low-pressure mercury lamps for photopolymerization to obtain a plastic optical transmission body with a diameter of 1 square inch.

When the refractive index distribution of this light transmission body was measured using an interfaco interference microscope, the refractive index at the center was 1.487 and the refractive index at the outer periphery was 1.470, and it was found that the refractive index varied continuously from the center to the outer periphery.

Further, when this optical transmission body was cut into a length of 5 am and both ends thereof were polished and an image was observed, an inverted real image was observed.

Example 2 Benzyl methacrylate (polymer nゎ-1,56) 3
A mixture of 0 parts by weight, 20 parts by weight of methyl methacrylate, 50 parts by weight of polymethyl methacrylate, and 1 part by weight of l-hydroxycyclohexylphenyl ketone was uniformly mixed and inserted into the l cylinder (3) shown in Figure 1. The cylinder temperature at this time was 70° C. and extruded from the nozzle (4) with the piston (2).

Next, 5 m of N8 gas at 50°C! /win was introduced into the actinic ray irradiation section (5), and irradiated with ultraviolet rays for 30 seconds using eight 20W Kegokar lamps, resulting in photopolymerization to obtain a fiber with a monomer polymerization rate of 40%. The obtained fiber is introduced into a diffusion tank (6), and 2.2.3.3-tetrafluoropropyl methacrylate is diffused from the outer periphery of the fiber at a liquid temperature of 30° C. and for a contact time of 30 seconds.

Next, 5j! of N8 gas at 50°C! Ultraviolet rays were irradiated for 1 minute using three low-pressure mercury lamps in the actinic ray irradiation section (7) flowing at /sin for photopolymerization to obtain a plastic optical transmission body with a diameter of 1 inch.

When the refractive index distribution of this light transmission body was measured using an interfaco interference microscope, the refractive index at the center was 1.505 and the refractive index at the outer periphery was 1.465, and it was found to change continuously from the center to the outer periphery.

Furthermore, when this optical transmission body was cut into a length of 2.7 mm, both ends of which were polished and the image observed, an inverted real image was observed.

Example 3 Benzyl methacrylate (polymer n, -1,56) 3
A mixture of 0 parts by weight, 20 parts by weight of methyl methacrylate, 50 parts by weight of polymethyl methacrylate, and 1 part by weight of 1-hydroxycyclohexylphenyl ketone was uniformly mixed and inserted into the cylinder (3) shown in FIG. , the cylinder temperature at this time was 70''C.

Next, N8 gas at 50°C is 54! The fiber was guided to the actinic ray irradiation section (5) flowing at /sin, and irradiated with ultraviolet rays for 30 seconds using eight 20-inch lamps, resulting in photopolymerization to obtain a fiber with a monomer polymerization rate of 40%. The obtained fiber is guided to the diffusion tank (6) and 2.2.3.3.4, 4, 5.5
- Octafluoropentyl methacrylate at a liquid temperature of 30℃
The contact time between the two was 30 seconds, and the fiber was diffused from the outer periphery.

Next, in the actinic ray irradiation section (7) where N8 gas at 50°C is flowing at 51/inch, ultraviolet rays are irradiated with three low-pressure mercury lamps.
It was irradiated for a minute and photopolymerized to obtain a plastic optical transmission body with a diameter of 1 m.

When the refractive index distribution of this light transmission body was measured using an interfaco interference microscope, the refractive index at the center was 1.500 and the refractive index at the outer periphery was 1.461, and it was found to change continuously from the center to the outer periphery.

Furthermore, when this optical transmission body was cut into a length of 2.8 cm and both ends were polished and the image was observed, an inverted real image was observed.

[Effects of the Invention] The manufacturing method of the present invention overcomes the difficulty of manufacturing an optical transmission body with a uniform refractive index distribution, which was the problem with the prior art, and the unreasonableness of the production process being intermittent. This solution made it possible to produce continuous optical transmission bodies.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the method of manufacturing a plastic optical transmission body of the present invention. 2... Piston 3... Cylinder 4... Nozzle 6... Diffusion tank 5.7... Actinic ray irradiation section 8... Nip roller 9... Light transmission body

Claims (1)

[Claims] A mixture of monomer (A) and polymer (B) is shaped into a fiber, and a portion of monomer (A) is polymerized. A monomer (C) that becomes a polymer with a refractive index is diffused from the outer periphery of the fiber, and a monomer (A)
A method for producing a plastic optical transmitter having a continuous refractive index distribution from the center to the outer periphery, the method comprising forming a concentration distribution of a monomer (C) and then polymerizing unpolymerized monomers.