JPH0342604A - Production of light transmission body made of plastic - Google Patents

Abstract

PURPOSE:To allow continuous production by imparting a continuous refractive index distribution from the center toward the outer periphery of a columnar material comprising polymn. of unpolymeized monomers. CONSTITUTION:A mixture composed of the monomer C which applies a polymer B having the refractive index higher than the refractive index of a polymer A to the hollow part of a hollow yarn-shaped body or a monomer mixture composed of the monomer C and other monomer D forming a transparent polymer and a transparent polymer E is charged into a cylinder 1 and is heated by a heater 3. The mixture is passed at a constant rate in a kneading part by a piston 4 and is extruded and packed as the uniform compsn. While the extrusion is kept at a circular cylindrical shape and is pulled up at a constant speed into the temp. insulating column 7, the monomer C or the monomer C and the monomer D are diffused into the wall part of the hollow yarn 6 of the polymer A to apply such a refractive index distribution as to lower the refractive index from the central part of the columnar body toward the outer periphery thereof. The polymer is introduced to an irradiating part 8 of active rays where the polymer is polymerized and solidified. The fiber is then taken up on a take-up drum 11 via nip rollers 10. The continuous production is executed in this way.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a continuous curvature distribution from the center to the outer periphery of a plastic columnar body used in light-focusing lenses, light-focusing fibers, etc. The present invention relates to a method of manufacturing a plastic optical transmission body having the following properties.

[Prior Art] As an optical transmission body having a continuous curvature distribution from the center to the outer periphery of a columnar body, one made of glass has already been proposed in Japanese Patent Publication No. 47-816. However, the productivity of gradient index optical transmission bodies made of glass is low;
It has the problems of being expensive and having poor flexibility.

In contrast to such a gradient index optical transmission body made of glass, several methods have been proposed for manufacturing a gradient index optical transmission body made of plastic.

The manufacturing method of plastic optical transmitters having a continuous refractive index distribution from the center to the outer circumference of these plastic columnar bodies can be roughly divided into: (1) from the central axis of a synthetic resin rod made of an ionically crosslinked polymer to its surface; A device in which the concentration of metal ions is continuously changed toward
726913), (2) A synthetic resin columnar body manufactured from a mixture of two or more transparent polymers having different refractive indexes is treated with a specific solvent, and at least one of the constituent bones of the synthetic resin body is treated with a specific solvent. (Japanese Patent Publication No. 47-28059), (3)
A method in which a mixture of two monomers with different refractive indexes is polymerized into a columnar shape by devising a polymerization method to create a continuous refractive index distribution from the surface to the inside (Japanese Patent Publication No. 54-30
301 Publication), (4) A monomer having a lower refractive index than the surface of the columnar crosslinked polymer is diffused toward the inside, and the content of this monomer is arranged so as to change continuously from the surface to the inside. Those that are later polymerized to give a refractive index distribution (Japanese Patent Publication No. 52-5857, Japanese Patent Publication No. 56-37521), and (5) Reactive columnar polymers from the surface to the inside. , a method in which a low-molecular compound having a refractive index lower than that of the polymer is diffused and reacted to provide a continuous refractive index distribution from the surface to the interior (Japanese Patent Publication No. 57-29682).

Common problems with conventional methods for producing these gradient index columnar bodies include the long time it takes to diffuse or extract various compounds into the columnar bodies, and the length of the columnar bodies is limited. It is an intermittent production method, in other words, it is a batch production method, which has extremely low productivity, and at the same time, it is extremely difficult to select manufacturing conditions and cannot achieve reproducibility.
As industrial technologies, each manufacturing method has its own problems.

[Problems to be Solved by the Invention] The present invention solves the irrationality caused by the intermittent production process of the above-mentioned prior art, and enables continuous production similar to glass or plastic optical fibers. It is.

"Means for Solving the Problems" That is, the gist of the present invention is to form a polymer (A) with a low refractive index into a hollow shape, and form a polymer with a higher refractive index than the polymer (8). Monomer (C) alone that provides polymer (B), or monomer (D) that can form a transparent polymer with monomer (C)
A polymerizable composition consisting of a monomer mixture containing a transparent polymer (E) and a transparent polymer (E) is filled into the hollow interior to form a thread, and then the monomer (C) is diffused into the polymer (A). After or while providing a continuous concentration distribution of the monomer (C) and, if necessary, the monomer (D) from the center to the outer periphery of the filament, these unpolymerized monomers are polymerized. A method of manufacturing a plastic light transmitting body is characterized in that a continuous refractive index distribution is imparted from the center to the outer periphery of a columnar object.

An example of the method for manufacturing the gradient index plastic optical transmission body of the present invention is shown in FIG. First, a transparent polymer (A) having a relatively low refractive index is extruded from an extrusion nozzle head (5) into a hollow system. The polymer (A
) gives a polymer (B) with a higher refractive index than the monomer (C
) or a monomer mixture of the monomer (C) and another monomer (D) capable of forming a transparent polymer, and a transparent polymer (E)
A mixture of
) and quantitatively passed through a kneading section with a piston (4) to form a uniform composition, which is then extruded and filled. Next, while maintaining this extrudate in a cylindrical shape, it is pulled up at a constant speed and introduced into the heat-retaining group (7), and the monomer (C)
Alternatively, the monomer (C) and the monomer (D) are diffused into the wall of the hollow fiber (6) of the polymer (A), so that the refractive index decreases from the center of the columnar body toward the outer periphery. While or after giving a refractive index distribution such that
10) is wound around the drum (11) to obtain the desired graded index plastic optical transmission body. At this time, improving the temperature controllability of the heat retaining base (7),
In order to increase the irradiation efficiency of actinic rays, gas introduction holes (9
) It is better to introduce a gas such as nitrogen or argon.

Specific examples of the transparent polymer (A) used in carrying out the present invention include acrylic polymers including polymethyl methacrylate, styrenic polymers including polystyrene, polycarbonates, and polyfluoroalkyl (meth). Acrylate homopolymers or copolymers,
Examples include copolymers mainly composed of vinyldene fluoride and tetrafluoroethylene, copolymers of perfluoro 2,2-dimethyl-L3-dioxole and other fluorine-containing monomers, etc. It is necessary that a transparent hollow fiber-like product can be formed by extrusion molding.

Specific examples of the monomer (C) that can produce a polymer with a higher refractive index than the polymer (A) when carrying out the present invention include methyl (meth)acrylate, benzyl (meth)acrylate, and cyclohexyl (meth)acrylate. , adamantyl (meth)acrylate, divinylbenzene, n-butyl (meth)acrylate, etc., and these monomers (C) have a refractive index of the polymer. 0.0 with respect to the refractive index of the polymer (A).
It is preferable to select a value larger than 0.01, preferably larger than 0.03.

When carrying out the present invention, monomers (D
) can be the same monomer as the monomer shown in monomer (C). In this case, the monomer (D) can be one that can form a polymer with a different refractive index from that of the monomer (C), and the monomer (C) and monomer (D) By using a monomer mixture, the center of the columnar body can be made into a refractive index distribution type plastic optical transmitter with a large refractive index difference from the outer periphery, or a refractive index distribution type plastic with a clear quadratic curve distribution type can be formed. It becomes possible to obtain optical transmission bodies.

The polymer (E) used in combination with monomer (C) or a monomer mixture of monomer (C) and monomer ('D) is the polymer (E) used to make the hollow fiber material ( The same polymers as in A) can be used. To obtain a refractive index distribution type plastic optical transmitter whose refractive index distribution approximates a quadratic curve distribution, polymer 1 is used.
As '), it is preferable to use a polymer having the same or almost the same refractive index as the polymer (A).

According to the method of the present invention, unlike the conventional method for manufacturing a refractive index distribution type plastic optical transmitter, it is extremely easy to make the manufacturing process continuous, and the columnar shape of the compound for imparting the refractive index distribution is very easy. It has the great feature that there is no need to use inconvenient and complicated processes such as volatilization and extraction of substances, and that it is possible to produce a refractive index distribution type plastic optical transmission body with a uniform refractive index distribution.

The present invention will be explained in more detail with reference to Examples below.

Example 1 Poly-(2,2,3,3-tetrafluoropropyl methacrylate) (Nn = 1.423, [η) 0.5
5 (measured on M1! at 25°C) at 220°C into a hollow shape with an outer diameter of 1, an inner diameter of 0.5 mm, and poly(2,2 ,3,3-tetrafluoropropyl methacrylate) (ND=1.423, [
η) 2.98 (MEK, measured at 25°C) 50 parts by weight, 50 parts by weight of methyl methacrylate (refractive index of the monomer polymer ND = 1.489), 1-hydroxycyclohexylphenyl ketone 1 Parts by weight are uniformly mixed and inserted into the cylinder (1) shown in FIG. 1, and then passed through the kneading section (2) and extruded from the nozzle (5). After obtaining a composite strand fiber in this way, this strand fiber (6) was heated to 70°C with N2 gas at 51! ,/min
20 + 10 after 3 minutes.
The product was photopolymerized by irradiation with ultraviolet rays from 8 Kegokar lamps for 3 minutes to obtain a gradient index optical transmission body with a diameter of 1.0 mm.

When the refractive index distribution of this optical transmission body was measured using an interfaco interference microscope, the refractive index at the center was 1,452 and the refractive index at the outer periphery was 1.428, which changed continuously from the center to the outer periphery. .

Furthermore, when both ends of this optical transmission body were polished to a length of 3.2 mm and an image was observed, an inverted real image was observed.

Example 2 Polymethyl methacrylate (ND=1.489, [η)
0.36 (MEK, measured at 25°C) to 23
A hollow shape with an outer diameter of 0.95 mm and an inner diameter of 0.78 mm was formed at 0°C, and polymethyl methacrylate (Nn -1,489, [η) 0.36 (
MEK, measured at 25°C) 50 parts by weight, Hensyl methacrylate 40 parts by weight (polymer refractive index N of the monomer,
-10 parts by weight of 1,568L methyl methacrylate (polymer refractive index of the monomer ND-1,489) and 1 part by weight of 1-hydroxycyclohexylphenyl ketone were placed in the cylinder (1) shown in FIG. The mixture is uniformly mixed and inserted into the kneading section (2), and then extruded from the nozzle (5). After obtaining a composite strand fiber in this way, this strand fiber (6) was heated to 542/m of N2 gas at 70°C.
After 3 minutes, it was irradiated with ultraviolet rays for 3 minutes using eight 20-liter chemical lamps for photopolymerization to obtain a gradient index optical transmission body with a diameter of 1.0 mm. .

When the refractive index distribution of this optical transmission body was measured using an interfaco interference microscope, the refractive index at the center was 1.515 and the refractive index at the outer periphery was 1.495, and it changed continuously from the center to the outer periphery. .

Furthermore, when both ends of this optical transmission body were polished to a length of 2.7 m+n and the image was observed, an inverted real image was observed.

[Brief explanation of drawings]

Claims (1)

[Claims] A monomer (C) alone, or a monomer (C) that shapes a low refractive index polymer (A) into a hollow shape and simultaneously provides a polymer (B) with a higher refractive index than that polymer. A polymerizable composition consisting of a monomer mixture containing a monomer (D) capable of forming a transparent polymer and a polymer (D) is filled into a hollow interior to form a thread, and then the monomer After or while providing a continuous concentration distribution of monomer (C) from the center to the outer periphery of the filament by diffusing (C) into the polymer (A), unpolymerized monomer 1. A method for producing a plastic light transmitting body having a continuous refractive index distribution from the center to the outer periphery, the method comprising polymerizing the body.