JPH0216505A - Plastic light transmission body and production thereof - Google Patents

Abstract

PURPOSE:To allow continuous production and to obtain the light transmission body having good transparency by forming said body of a polymerizable mixture essentially composed of methyl methacrylate and/or fluorinated alkyl methacrylate and changing the polymn. ratio of the two polymers from the inside of the light transmission body toward the surface. CONSTITUTION:The ratio of the fluorinated alkyl methacrylate in the polymerixable mixture is preferably 0-80wt.%, more, particularly preferably 0-60wt.%. The polymerizable mixture is required to have 10<3>-10<5> poise and is produced by using a yarn molding device. The desired distributed index type light transmission body 6 is obtd. by concentrically extruding 1>=2 kinds of the polymerizable mixtures having the different ratios of the fluorinated alkyl methacrylate units, diffusing 3 the monomers of the polymerizable mixtures between the respective layers to each other during the passage in a guide pipe to apply a refractive index distribution, then subjecting the molding to polymerization curing 4. The distributed index type plastic light transmission body 6 having good flexibility is continuously and efficiently produced in this way.

Description

[Detailed description of the invention] [Industrial application field] The present invention has a continuous refractive index distribution from the surface to the inside,
This invention relates to a plastic optical transmission body used for light-focusing X-Z, light-focusing optical fiber, optical IC, etc., and a method for manufacturing the same.

[Conventional technology]

As an optical transmission body having a continuous refractive index distribution from the surface to the inside, a glass one has already been proposed in Japanese Patent Publication No. 47-816. However, optical transmission bodies made of glass have the problems of low productivity (and high price), and poor flexibility.In contrast to such optical transmission bodies made of glass, optical transmission bodies made of plastic Several methods have been proposed for manufacturing bodies.

These plastic optical transmitters that have a continuous refractive index distribution from the surface to the inside can be roughly divided into: (1) metal ions that are continuously directed from the central axis of the synthetic resin body made of an ionically crosslinked polymer toward the surface; (2) Synthetic resin bodies made from a mixture of two or more transparent polymers with different refractive indexes are treated with a specific solvent. , produced by partially dissolving and removing at least one of the constituent components of the synthetic resin body (Japanese Patent Publication No. 47-28059)
, (!t) Two types of monomers with different refractive indexes were created by devising a polymerization method to create a continuous refractive index distribution from the surface to the inside (%
(Refer to Publication No. 54-50501) (4) Diffusion of monomer i having a lower refractive index than the polymer from the surface of the crosslinked polymer, so that the content of the monomer changes continuously from the surface to the inside. (5) Polymerized from the surface of the reactive polymer, which is then polymerized to give it a refractive index distribution (see Japanese Patent Publication No. 52-5857 and Japanese Patent Publication No. 57521/1983). Examples include those in which a low-molecular compound having a refractive index lower than that of a coalescence is diffused and reacted to provide a continuous refractive index distribution from the surface to the interior (see Japanese Patent Publication No. 57-29682).

[Problems to be solved by the invention] These conventional methods have low productivity because diffusion or extraction processes require a long time, the length of the optical transmission body is limited, and the production process is intermittent. There are problems such as extremely low performance, difficulty in selecting manufacturing conditions, and inability to achieve reproducibility.

The present invention solves the unreasonableness of the conventional intermittent production process, enables continuous production, and provides an optical transmission body with good transparency and a method for manufacturing the same.

[Means to solve the problem]

The present invention provides a plastic optical transmitter made of a polymer mixture mainly composed of methyl methacrylate and/or fluorinated alkyl methacrylate, in which the mixing ratio of both polymers changes from the inside of the optical transmitter toward the surface. It is.

The plastic optical transmitter of the present invention is a (co)polymer of methyl methacrylate or fluorinated alkyl methacrylate (
Produced by extruding two or more polymerizable mixtures containing A) and methyl methacrylate and/or fluorinated alkyl methacrylate (B) as main components and having different amounts of fluorinated alkyl methacrylate in a concentric manner, and then polymerizing and curing the mixture. be able to.

The (co)polymer (A) of methyl methacrylate or fluorinated alkyl methacrylate used in the present invention includes:
Methyl methacrylate homopolymer, fluorinated alkyl methacrylate homopolymer, 6-copolymer of methyl methacrylate and fluorinated alkyl methacrylate, methyl methacrylate or fluorinated alkyl methacrylate with other copolymerizable monomers, etc. ”.

Examples of fluorinated alkyl methacrylate include C2,2.
2-trifluoroethyl methacrylate, 2.2,3.
3-tetrafluoroglovir methacrylate, 2,2.
S, 4.4.4-hexafluorobutyl methacrylate, 2,2,3,3,4,4,5.5-octafluoropentyl methacrylate, and the like.

Examples of other copolymerizable monomers include the following compounds. Monofunctional (meth)acrylates such as ethyl (meth)acrylate, n-propyl (meth)acrylate, inglovir (meth)acrylate, tertiary butyl (meth)acrylate, cyclohexyl (meth)acrylate
Acrylate, 2-hydroxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate), 2
-(n-7"toxy)ethyl (meth)acrylate, glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, etc., fluorinated alkyl acrylates such as 2, 2.2-) Lifluoroethyl acrylate, styrene, chlorostyrene, methacrylic acid, acrylic acid, polyfunctional (meth)acrylates such as alkylene glycol di(meth)acrylate, trimethylolpropane di- or tri(meth)acrylate, penta In addition to erythritol g-tri or tetra(meth)acrylate, diglycerin tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, diethylene glycol pisallyl carbonate), 144 alkylene glycol poly(meth)
acrylate etc.

When manufacturing the optical transmission body of the present invention, first, methyl methacrylate or fluorinated alkyl methacrylate ((
Two or more types of polymerizable mixtures containing the co-)polymer (A) and methyl methacrylate and/or fluorinated alkyl methacrylate (B) as main components and having different amounts of fluorinated alkyl methacrylate are prepared. At that time, a thermosetting catalyst and/or a photocuring catalyst is also added.

The ratio of the (co)polymer (A) and monomer (B) in the polymerizable mixture is usually A:B=mouth, 1.:999 to 99 by weight.
, 9: 0.1. The amount of fluorinated alkyl methacrylate in the polymerizable mixture is from 0 to 80% by weight, especially from 0 to 60% by weight.
Weight percent is preferred. It is also possible to replace part of the methyl methacrylate of monomer (B) with other methacrylates, such as phenyl methacrylate.

A common peroxide catalyst is used as the thermosetting catalyst. As a photopolymerization catalyst, benzophenone, benzoin alkyl ether 4/-improvil-2-hydroxy-2-methyl-propiophenone, 1-hydroxycyclohexylphenyl ketone, benzyl methyl ketal, 2,2-jethoxyacetophenone, chloro Examples include thioxanthone, thioxanthone compounds, benzophenone compounds, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, N-methyljetanolamine, and triethylamine.

The polymerizable mixture must have a viscosity of 103 to 105 voids and be curable. If the viscosity is less than 103 poise, yarn breakage occurs during spinning, making it difficult to form a filament. Moreover, if the viscosity is greater than 105 poise, the spinning operability will be poor and it will be difficult to obtain a filamentous material with low accounting properties.

Next, two or more types of polymerizable mixtures having different amounts of fluorinated alkyl methacrylate units are extruded concentrically, and while passing through a guide tube, the monomers of the polymerizable mixture between each layer are diffused into each other, and then polymerized and hardened. By doing so, the desired refractive index gradient type optical transmission body can be obtained.

In the monomer interdiffusion section, the thread-like material can be heated if necessary, but in any case, it is maintained in an uncured state during that time.

Next, in order to cure the uncured filamentous material, the filamentous material containing the thermosetting catalyst and/or photocuring catalyst is subjected to heat treatment or light irradiation treatment, preferably by applying ultraviolet rays from the surroundings in the curing section.

The gradient index optical transmission body of the present invention can be manufactured using, for example, the thread forming apparatus shown in FIG. Figure 1 is a process diagram that schematically shows the thread forming device, with only the interdiffusion section being a vertical cross-sectional view. A filamentous material, 3 is a mutual diffusion-4 part for mutually diffusing the monomers in each layer of the filamentous material to give a refractive index distribution, 4 is a curing treatment section for curing the uncured material, and 5 is a take-up roller. 6 is a refractive index gradient plastic optical transmission body, 7 is a winding portion, 8 is an inert gas inlet, and 9 is an inert gas outlet. In order to remove volatile substances liberated from the filamentous material 2 from the interdiffusion section 6 and the curing section 4, an inert gas such as nitrogen gas is introduced from the inert gas inlet 8.

The gradient index optical transmission body of the present invention may further be provided with a coating layer having a low refractive index. To form the coating layer, trifluoroalkyl acrylate, pentafluoroalkyl acrylate, hexafluoroalkyl acrylate, fluoroalkylene diacrylate), 1,
1,2.2-Tetrahydrohebbutadecafluorodecyl acrylate, hexanediol diacrylate, neopentyl glycol diacrylate, dipentaerythritol hexaacrylate, etc. are appropriately mixed to adjust coating properties and refractive index as necessary. It is preferable to use a polymer in which the above-mentioned fluorinated acrylate or methafrylate polymer is added to the above-described photopolymerization initiator.

Light sources for photopolymerization include carbon arc lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, low-pressure mercury lamps, chemical lamps, and xenon lamps that emit light with a wavelength of 150 to 600 nm.1. Laser light or the like is used.

[Effects of the present invention]

According to the present invention, it is possible to continuously and efficiently manufacture a refractive index gradient plastic two-light transmitter having good flexibility. Furthermore, by changing the refractive index of the components of each layer of the gradient index plastic optical transmission body and the thickness of each layer, it is possible to easily control the refractive index distribution, which has been extremely difficult with conventional techniques.

Example 1 Polymethyl methacrylate ([η]=0.45, MEK
, 25°C) 50 parts by weight, methyl methacrylate 50 parts by weight, 1-hydroxycyclohexylphenyl ketone 0
．． 2 parts by weight and 0.1 part by weight of hydroquinone were heated to 70°C and kneaded to prepare a stock solution for the first layer. Also, polymethyl methacrylate ([η] = 0.34, MICK, 256C
), 55 parts by weight of 2,2.5.3-tetrafluoropropyl methacrylate, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone and 0.1 part by weight of hydroquinone were heated to 70°C and kneaded. This was used as the stock solution for the second layer. The stock solution for the first layer and the stock solution for the second layer were simultaneously extruded using a concentric compound nozzle. The viscosity during extrusion is
The stock solution for the first layer was 4.2 x 104 poise, and the stock solution for the second layer was 3.0 x 10' poise. Further, the heat retention temperature of the composite nozzle was 55°C.

Next, using the apparatus shown in Figure 1, the fiber was passed through a mutual diffusion section with a length of 90 crn, and then inserted into the center of a quartz tube around which 12 40 W fluorescent lamps with a length of 120 cm were arranged at equal intervals. was passed at a speed of 25 cm for 7 minutes to cure, and then removed with a nip roller.

When the discharge ratio is 1:1 = 1:1, the obtained fiber has a diameter of 1000 μm, and the refractive index nD distribution measured with an Interfaco interference microscope (manufactured by Carl Zeiss, East Germany) shows that the center part is 1.490, peripheral area 1.45
9, and decreased continuously from the center to the periphery. The total amount of residual methyl methacrylate and 2,2.3.5-tetrafluoroglobyl methacrylate monomers was 0.8% by weight. Furthermore, as a result of measuring the lens performance, the image of the square lattice had less distortion.

In addition, when the ejection ratio is 1st layer: 2nd layer = 1:2, the obtained fiber has a diameter of 1060 μm, and the refractive index nD distribution is 1.487 at the center, 1,458 at the periphery, and It decreased continuously from the central part to the peripheral part. The total amount of residual monomers was 1.0% by weight. Furthermore, as a result of measuring lens performance, the square grid image had less distortion.

Example 2 Polymethyl methacrylate ([η) = 0.45, MEK
, 25°C) 50 parts by weight, methyl methacrylate) 401
10 parts by weight of phenyl methacrylate, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone, and 0.1 parts by weight of hydroquinone were heated to 60°C and kneaded.
It was used as a stock solution for the layer. Also, polymethyl methacrylate ([η
]=0°40, MEK 125°C) 48 parts by weight, 40 parts by weight of methyl methacrylate, 12 parts by weight of 2.2,5.5-tetrafluoropropyl methacrylate, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone, and hydroquinone. 0.1 part by weight was heated to 60°C and kneaded to obtain a stock solution for the second layer. In addition, polymethyl methacrylate ((V
) = O, S4, MEK.

25°C) 40 parts by weight, 2,2,5.5,4,4,5,5
-octafluoropentyl methacrylate-) 40ii parts,
20 parts by weight of methyl methacrylate, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone, and 0.1 parts by weight of hydroquinone were heated to 60°C and kneaded to prepare a stock solution for the third layer. The stock solutions of the first layer, second layer, and third layer were simultaneously extruded using a concentric compound nozzle. The viscosity of the first layer stock solution during extrusion was 5. OX 10' voids, the stock solution for the second layer was 3.5 x 10' voids, and the stock solution for the third layer was 2°4 x 10' voids. Further, the heat retention temperature of the composite nozzle was 60°C.

Next, using the apparatus shown in FIG. 1, the fiber was passed through an interdiffusion section having a length of 45 cm, and a fiber was obtained in the same manner as in Example 1.

When the ejection ratio is 1st layer: 2nd layer: 3rd layer = 2:1:1,
The obtained fiber had a diameter of 1020 μm, and the refractive index nc+15 distribution measured using an interfaco interference microscope was 1.497 at the center and 1°459 at the periphery.
It decreased continuously from the center to the periphery. The total monomer residue was 0.9% by weight. Furthermore, as a result of measuring the lens performance, the image of the square lattice had less distortion.

When the ejection ratio is 1st layer: 2nd layer: 6th layer == -1:1:1, the obtained fiber has a diameter of 998 μm, and the refractive index distribution is 1.489 at the center and 1.489 at the periphery. It was 1.456, and decreased continuously from the center to the periphery. The total monomer residue was 1.2% by weight. Furthermore, as a result of measuring the lens performance, the image of the square lattice had less distortion.

Example 3 Polymer consisting of 50% by weight of methyl methacrylate and 50% by weight of 2.2.6.3 tetrafluoroglobyl methacrylate (nD=1,456, [η]1,00) 50
parts by weight, 50 parts by weight of methyl methacrylate,
0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone and 0.1 parts by weight of hydroquinone were heated to 70°C;
The mixture was kneaded to obtain a stock solution for the first layer. Also, 45 parts by weight of the same polymer as the first layer, 554 parts by weight of 2.2,3.3-tetrafluoropropyl methacrylate, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone, and 7 parts by weight of 1-hydroxycyclohexylphenyl ketone.
0.1 part by weight was heated to 70°C and kneaded to prepare a stock solution for the second layer. The stock solution for the first layer and the stock solution for the second layer were simultaneously extruded using a concentric compound nozzle. The viscosity during extrusion is 4.0 x 104 poise for the first layer stock solution and 2.0 x 104 poise for the second layer stock solution.
．． It was 3 x 104 voices. Further, the heat retention temperature of the composite nozzle was 60°C.

Next, using the apparatus shown in FIG. 1, a fiber was obtained in the same manner as in Example 1 (the interdiffusion portion was 90 crn).

When the ejection ratio is 1st layer: 2nd layer = 1:1, the obtained fiber has a diameter of 1050 Am, and the refractive index nD-distribution measured by an interfaco interference microscope is 1 at the center.
．． 475 and 1°439 at the periphery, decreasing continuously from the center to the periphery. The residual content of methyl methacrylate and 2,2,3,3-tetrafluoropropyl methacrylate was 1.0% by weight. Furthermore, as a result of measuring the lens performance, the image of the square lattice had less distortion.

When the ejection ratio is 1st layer: 2nd layer = 1:2, the obtained fiber has a diameter of 1000 μm, and the refractive index distribution is 1.468 at the center and 1°466 at the periphery. It decreased continuously from the center to the periphery. Also the first
The distribution curve was different from that in the case of a discharge ratio of layer:second layer=1:1. The total monomer residue was 1.2% by weight. Furthermore, as a result of measuring the lens performance, the image of the square lattice had less distortion.

Example 4 Poly(2,2,3,3-tetrafluoropropyl methacrylate) ([η)=3.01, MEK, 25°C) 50
parts by weight, 50 parts by weight of methyl methacrylate, 0.2 parts by weight of 1-hydroxycyclohexylphenyl ketone, and 0.1 parts by weight of hydroquinone were heated to 70°C and kneaded to prepare a stock solution for the first layer. Also, poly(2,2,3,3-tetrafluoropropyl methacrylate) ([η)=3.01
, MEK, 25°C) 45 parts by weight, 2,2,3.3-
Tetrafluoropropyl methacrylate 55 parts by weight, 1
-Hydroxycyclohexylphenylketone o, :[1
part by weight and 0.1 part by weight of hydroquinone were heated to 70°C and kneaded to prepare a stock solution for the second layer. The stock solution for the first layer and the stock solution for the second layer were simultaneously extruded using a concentric compound nozzle. The viscosity of the first layer stock solution during extrusion was 4. OX 10'poise, and the stock solution for the second layer was 2.5 x 104 poise.

The heat retention temperature of the composite nozzle was 60°C.

Next, using the apparatus shown in FIG. 1, a fiber was obtained in the same manner as in Example 1 (the interdiffusion portion was 90 crn).

When the ejection ratio is 1st layer: 2nd layer = 1 = 1, the obtained fiber has a diameter of 980 μm, and the refractive index n8 distribution measured by an interfaco interference microscope is 1.45 at the center.
5. The peripheral area was 1.436, and it decreased continuously from the center to the peripheral area. Methyl methacrylate and 2
．． The residual content of 2,3.3-tetrafluoroprobyl methacrylate monomer was 1.1% by weight. Furthermore, as a result of measuring the lens performance, the image of the square lattice had less distortion.

In addition, the lens performance and refractive index distribution in the examples were measured by the following method.

1. Measurement of lens performance Evaluation device Lens performance was measured using the apparatus shown in FIG.

He-N passing through the optical transmission body obtained in Sample Preparation Example
e Period of the light beam (λ) determined from the undulation of the laser beam
The sample was cut to approximately 1/4 length (λ/4), and polished using a polishing machine so that both end surfaces of the sample became parallel planes perpendicular to the long axis, and used as an evaluation sample.

Measurement method: Set the prototype evaluation sample (18) on the sample stage (16) placed on the optical pliers (11), and
4) so that the light from the light source (12) passes through the condensing lens (
13) After passing through the diaphragm (14) and the glass plate (15) so that the light is incident on the entire end face of the sample, adjust the positions of the sample (18) and Polaroid camera (17) so that they are focused on the Polaroid film. Then, a square lattice image was taken and the distortion of the lattice was observed. The glass plate (15) used was a chrome-plated glass for photomasks that had a chrome coating precisely processed into a 0.1 fl square grid pattern.

(2) Measurement of refractive distribution Measurement was carried out by a known method using an Interfaco interference microscope manufactured by Carl Zeiss.

BRIEF DESCRIPTION OF THE FIRST DRAWINGS FIG. 1 is a process diagram schematically showing the thread forming apparatus used for manufacturing the optical transmission body of the present invention, and only the interdiffusion part and the curing part are shown in longitudinal section. , Fig. 2 is a partially longitudinal side view schematically showing the lens performance measuring device, in which symbol 1 is a concentric compound nozzle, 2 is a filamentous material, 3 is a mutual diffusion part, and 4 is a hardening treatment part. , 6 is an optical transmission body, 12 is a light source, 1
3 is a lens, 14 is an aperture, 15 is a glass plate, 17 is a camera, and 18 is a sample.

Claims (1)

[Claims] 1. A plastic made from a polymer mixture mainly composed of methyl methacrylate and/or fluorinated alkyl methacrylate, in which the mixing ratio of both polymers changes from the inside to the surface of the optical transmitter. optical transmission body. 2. Two or more types of polymerizable polymers whose main components are a (co)polymer of methyl methacrylate or fluorinated alkyl methacrylate (A) and methyl methacrylate and/or fluorinated alkyl methacrylate (B), with different amounts of fluorinated alkyl methacrylate A method for manufacturing a plastic optical transmitter, characterized by extruding a mixture in concentric circles and then polymerizing and curing the mixture to produce an optical transmitter having a refractive index that changes sequentially from the inside toward the surface.