JPH0579962B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing a synthetic resin light transmitting body having a refractive index distribution, and more particularly to a technique that enables continuous production of a synthetic resin light transmitting body. [Summary of the Invention] The present invention provides a method for manufacturing a synthetic resin optical transmission body, in which a prepolymer is supplied to a molded tube and continuously molded into a base material having self-shape retention. By installing a molding nozzle in the molding nozzle and letting liquid seep out from the molding nozzle, it is possible to prevent the base material from adhering to the molded tube and to prevent the monomers diffused into the base material from entering the molded tube. This makes it possible to stably and continuously manufacture synthetic resin optical transmission bodies over a long period of time. [Prior Art] A transparent rod-shaped body having a refractive index distribution that decreases approximately in proportion to the square of the distance from the central axis is known as a light transmission body. This transparent rod-shaped body has a convex lens effect, and its refractive index distribution is expressed by the following formula (1) n(r)=n ₀ (1-1/2Ar ² )...(1) (where n(r ) is the refractive index at a point at a distance r from the central axis, n ₀ is the refractive index at the central axis, and A is a positive constant. A light beam meanderingly propagates through such a transparent rod-shaped body, and its period L is expressed by the following formula (2) L=2π/√...(2) (where A is the same as above). expressed. In addition, the following formula (3) n(r)=n ₀ (1+1/2Br ² ) ...(3) (where n(r) and n ₀ are the same as above,
B is a positive constant. ) A transparent rod-shaped body having a refractive index distribution that increases in proportion to the square of the distance from the central axis becomes a light transmission body having a concave lens effect. Japanese Patent Publication No. 52-5857 (hereinafter referred to as Patent Application 1), Japanese Patent Application Publication No. 16394-1988 (hereinafter referred to as Patent Application 2), Japanese Patent Publication No. 56-37521 (hereinafter referred to as Patent Application 3), and Publication No. 182702/1983 (hereinafter referred to as Patent Application 4) discloses that a transparent gel body of a network polymer obtained by partially polymerizing a crosslinkable monomer Ma has a refractive index different from that of the network polymer. By bringing the monomer Mb that produces a polymer with a refractive index into contact with the surface of the transparent gel object in a liquid phase, gas phase, or droplet state, and polymerizing it after being diffused into the interior or simultaneously with the diffusion. discloses a method for manufacturing a synthetic resin light transmitting body in which the refractive index changes continuously from the surface toward the inside. In addition, Japanese Patent Application Laid-Open No. 12509/1982 (hereinafter referred to as Patent Application 5) and Japanese Patent Application No. 1983/1988 (hereinafter referred to as Patent Application 6) disclose that a synthetic resin optical transmission body is manufactured continuously. A method for continuously manufacturing the base material is described. In the methods described in these applications, when forming the base material, monomer Ma is prepolymerized, and the general formula (4) expressing plastic flow is D = Kσ ⁿ ... (4) (where D is A prepolymer exhibiting plastic flow with a value of n of 1.10 or more at 20°C (shear rate, σ is shear stress, K is the reciprocal of plastic viscosity, and n is a constant) is obtained, and then this prepolymer is elongated. The above-mentioned base material is obtained by supplying it to a passage and heating and polymerizing it while advancing through this passage. The reasons for using the prepolymer under the above conditions are as follows. When an object similar to a Newtonian fluid, such as a monomer or a low-viscosity prepolymer, is introduced into a long and narrow forming tube and is heated and polymerized while passing through the tube, the heat is applied from the outside of the tube. Polymerization proceeds from the peripheral region near the inner wall, and the viscosity increases accordingly. The fluid flowing inside the tube originally has a velocity distribution in which the flow velocity is maximum at the center and decreases parabolically toward the periphery, but as polymerization progresses, the phase between the peripheral region and the center region increases. The speed difference becomes even larger. and,
Ultimately, the fluid in the peripheral region gels first and stays in the tube, while the fluid in the central region flows out of the tube without much polymerization. In order to correct this, it is necessary to make the velocity distribution of the fluid within the pipe as constant as possible. That is, it is sufficient to bring the fluid in the pipe closer to Bingham fluid. In the case of Bingham fluid, n=∞ in the above equation (4), and the flow rate of the fluid in the pipe is constant.
As n becomes smaller and approaches 1, the fluid approaches a Newtonian fluid. Furthermore, the flow velocity of the fluid near the inner wall of the pipe does not change much depending on the value of n; rather, the larger n is, the sharper the parabola of the flow velocity distribution becomes. From this point of view, in Patent 5, the monomer Ma is prepolymerized as described above, and the value of n is increased.
It is made into a viscous liquid with a viscosity of 1.10 or higher before being sent into the molding tube. That is, its value is 1.10
If it is less than 100%, if the surrounding area is first gelled, the monomer Ma near the center will not be polymerized and will flow out of the tube, making it impossible to form a good base material. Also,
Preferably the value of n is at most 1.50. This is because if the value of n is too large, it becomes difficult to push the material into the pipe, and the base material becomes non-uniform, causing problems. The molded base material is continuously drawn out from the outlet of the molding tube and guided to a diffusion chamber, where monomer Mb in a liquid, gas, or mist state is diffused into the base material. . However, in this state, there is a problem in that the monomer Mb in the diffusion chamber enters the gap between the base material and the molded tube before the base material comes out of the molded tube. When the monomer Mb enters the molded tube in this manner, the monomer Mb diffuses from the surroundings into the prepolymer that is being molded into a base material having a predetermined cross-sectional shape. At this time, if the polymerization rate of monomer Mb or the copolymerization rate of monomer Mb and monomer Ma in the prepolymer is higher than the polymerization rate of monomer Ma, the surrounding area where monomer Mb has diffused In this case, polymerization proceeds further from the central region, and in order to keep the velocity distribution in the forming tube as constant as possible, the velocity distribution of the prepolymer changes as it is kept close to the Pingam fluid. In other words, the flow velocity in the peripheral region decreases and the velocity difference with the central region increases, and as a result, the prepolymer in the peripheral region remains on the molded tube wall, making the base material thinner and the surface uneven. This not only makes manufacturing conditions unstable, but also adversely affects optical performance. Furthermore, in the end, the prepolymer in the peripheral region gels first and stays in the molded tube, and as the flow area decreases, the prepolymer in the central region flows at a high speed, so the prepolymer in the central region gels first and stays in the molded tube. flowed out of the molded tube with almost no polymerization, resulting in the problem that the base material, which had been continuously molded, would break. The above patent application 6 includes monomers as mentioned above.
To prevent Mb from entering the molding tube, the gap between the molding base material and the inner wall of the molding means at the exit of the molding means is filled with a chemically inert liquid, the same monomer as the base material, etc. A method is described in which the base material is sealed with a sealing layer made of a liquid that does not substantially have an adverse effect on the base material, and the base material is continuously pulled out by such a manufacturing method, and the manufacturing methods of the above-mentioned patent applications 1 to 4 are described. A synthetic resin light transmitting body is continuously manufactured by passing through these steps continuously. [Problems to be Solved by the Invention] However, the conventional method described above has the following drawbacks. As mentioned above, monomer Ma is prepolymerized to form n
A viscous fluid with a value of 1.10 or more is used, and when molding into the base material by feeding this viscous fluid into a forming tube and thermally polymerizing it while advancing inside the tube, if the value of n exceeds 1.50, Inconveniences may occur if it becomes difficult to push into the pipe or if the base material becomes non-uniform. Therefore, since the viscosity cannot be increased indefinitely, a difference in flow velocity between the peripheral region and the central region still exists. Furthermore, the monomer Ma has poor thermal conductivity and acts as a heat insulating material, causing a difference in polymerization rate between the peripheral region and the central region. For this reason, polymerization progresses from the surrounding area, and the gelled product stays on the wall of the molded tube, resulting in a phenomenon similar to when monomer Ma invades the gap between the molding base material and the inner wall of the molded tube, as described above. As a result, irregularities appeared on the surface of the base material, and the base material was easily broken, making it extremely difficult to continuously manufacture synthetic resin optical transmitters. [Means for Solving the Problems] In view of the above-mentioned problems, the present invention partially polymerizes a monomer Ma that produces a network polymer Pa having a refractive index of Na to form a fluid prepolymer, and The polymer is supplied to a long and thin molding tube, and as it progresses through the molding tube, it is continuously molded into a self-shape-retaining base material by heating, and a refractive index different from the refractive index Na is formed by heating the polymer.
monomer Mb to produce polymer Pb with Nb,
In the method for manufacturing a synthetic resin light transmitting body having a refractive index distribution that is diffused from the surface of the base material to the inside thereof and polymerized, when molding the base material, the exit portion of the molded tube has liquid permeability. A molding nozzle made of a porous material is provided, and liquid is exuded from the molding nozzle to prevent the base material from adhering to the wall of the molded pipe and to seal between the base material and the molding nozzle. The present invention provides a method for manufacturing a synthetic resin optical transmission body characterized by the following. [Example] Next, an example of the method for manufacturing a synthetic resin optical transmission body according to the present invention will be described using the apparatus shown in the drawings. In FIG. 1, an extruder 1 cooled by cooling water contains a prepolymer, which is a viscous fluid used as a raw material for a synthetic resin light transmitting body. In this prepolymer, the monomer Ma is partially dissolved until immediately before gelation to maintain fluidity. Further, the extruder 1 has an extrusion tool (not shown), and the prepolymer 7 is extruded by this extrusion tool. After the prepolymer 7 has been extruded, it is subsequently introduced continuously into a forming tube 3 which passes through a heating jacket 2 consisting of a brass block or the like. This formed tube 3 has a circular cross section and a diameter of 1 to 20 mm.
It may be something like that. Here, if the lower end of the stainless steel tube is inserted into the formed tube 3 from above in advance, the tip of the prepolymer 7 will gel while in contact with the lower end of the stainless steel tube. and the tip of the prepolymer 7 are integrally bonded. Next, when the stainless steel tube is pulled up by a pulling device at the same speed as the extrusion speed, the prepolymer accompanying the stainless steel tube becomes a light transmitter during the entire manufacturing process and is continuously and without stagnation in the device. It is formed and comes out. The heating jacket 2 is supplied with relatively high-temperature water 10 at its upper part and lower-temperature water 11 at its lower part, and the formed tube 3 is heated with a temperature gradient such that the temperature gradually increases from the lower part to the upper part. It's heating up. The prepolymer 7 is gelled by thermal polymerization while passing through the forming tube 3, and this gelled prepolymer becomes a continuous cylindrical base material 8. The heating rate during this thermal polymerization is preferably 0.1 to 10°C/min. When the prepolymer 7 is heated under the temperature gradient described above, both the polymerization and the resulting increase in viscosity proceed gradually, and it is possible to use the prepolymer 7 as a Bingham fluid to flow the prepolymer 7 in a fluid state. becomes. As a result, it becomes possible to continuously mold the base material 8 having a uniform composition in the radial direction. Note that using a fluororesin tube as the molded tube 3 means that the prepolymer 7
The tube is particularly useful because of its low friction with the base material 8, but tubes made of other resins or metals may also be used. In this way, a transparent gel-like base material 8 having almost no fluidity and self-retaining properties is molded and comes out from the molding tube 3 in the heating jacket 2. This base material 8 preferably contains 5 to 90% by weight of components insoluble in acetone, that is, the network polymer portion.
More preferably, the content is 10 to 50% by weight. If this component is too small, the fluidity becomes high, and if it is too large, the diffusion rate of monomer Mb becomes too slow in the subsequent diffusion step, which is not preferable. A jacket 4 is provided on the outside of the forming tube 3 and extends along the forming tube 3 from just before the inlet of the heating jacket 2. Inside the jacket 4 is a sealing liquid 12 of a liquid sealing device to be explained later (see Fig. 2). ) is flowing. As shown in detail in FIG. 2, at the outlet of the molded tube 3, there is a molded nozzle (hereinafter simply referred to as a nozzle) 13 made of a porous material such as a sintered body of metal or synthetic resin that is permeable to liquid. The sealing liquid 12 flowing through the jacket 4 is connected to the nozzle 1.
2 and seep out onto the inner wall of the nozzle. This exuded sealing liquid 12 enters the gap between the inner wall of the nozzle and the prepolymer 7 that is being molded, acts as a lubricant, and coats the inner wall of the molded tube 3 and nozzle 13 with the prepolymer 7 that has previously gelled near the tube wall. This prevents the particles from accumulating in the forming tube 3 and the nozzle 13. The base material 8 that has exited the nozzle 13 is sent into the vapor phase diffusion device 5. A liquid sealing device 14 is attached to the lowermost end of the gas phase diffusion device 5 to prevent the monomer Mb from entering the nozzle 13. This liquid sealing device 14 is provided between the outlet of the nozzle 13 and the diffusion device 5, and has a liquid reservoir chamber 14a,
The sealing liquid 12 that has seeped out through the nozzle 13 is continuously sent into the chamber 14a and is discharged to the outside through the discharge port 15. The base material 8 that has passed through the sealing liquid 12 in the liquid reservoir chamber 14a and entered the diffusion device 5 is filled with the monomer Mb in any one of the liquid phase, gas phase, and mist state. It is guided to the diffusion chamber 5b inside the diffusion device 5, which is located inside the diffusion device 5. During a certain period of time when the base material 8 passes through the diffusion chamber 5b, the monomer Mb diffuses and moves in the radial direction from the peripheral surface of the base material. As a result, a concentration gradient is formed in the base material 8 in which the concentration of the monomer Mb gradually increases from the central axis toward the peripheral surface, and the refraction shown by the above formula (1) or formula (3) is created. A rate distribution is obtained. Regardless of whether the monomer Mb is in the liquid phase, gas phase, or atomized state, the gap between the nozzle 13 and the base material 8 is hermetically sealed with the sealing liquid 12, so that the base material 8
It does not enter the gap between the nozzle 13 and the nozzle 13 and diffuse into the prepolymer that is being molded into the base material. Therefore, the flow velocity distribution in the prepolymer is not adversely affected by the diffusion of the monomer Mb, and the base material does not have surface irregularities and there is no fear of breakage, and the base material with a good surface condition is continuous. pushed out. Since the sealing liquid 12 plays the role of a lubricant between the inner wall of the nozzle 13 and the base material 8, it is preferable to flow the sealing liquid 12 continuously as in the specific example described later. If it is allowed to flow, the concentration of the monomer Ma that seeps out (that is, diffuses) from the base material will always be constant, so the manufacturing conditions can be kept constant, and the monomer Ma in the sealing liquid can be kept constant. This is preferable because polymerization of the polymer Ma is prevented. From the above point of view, when flowing the sealing liquid, it is desirable that the flow rate be at least 10 ml or more per hour. Examples of the sealing liquid 12 that can be used in the present invention include the same monomer as the monomer Ma constituting the base material, or another monomer Mc different from the monomer Ma and the diffusion monomer Mb. When using a monomer Mc solution as above,
As long as the condition r _c ≦ r _a (where r _c is the monomer reactivity ratio of Mc, and r _a is the reactivity ratio of the base material monomer Ma), even if the refractive index is high, It doesn't matter if it's low. Another sealing liquid 12 that can be used in the present invention is a chemically inert liquid that does not chemically react with the base material and cannot diffuse into the base material and has a molecular volume larger than that of the monomer Ma. Examples include silicone oil, polyethylene glycol, water, and the like. However, when monomer Mb is to be diffused into the base material in a liquid phase, it is necessary to use a monomer or a chemically inert liquid that has a higher specific gravity than monomer Mb and is not soluble. The diffusion device 5 includes an outer tube 5 surrounding the diffusion chamber 5b.
a, and hot water 18 flows through this outer pipe 5a from an inlet 16 to an outlet 17. By heating the inside of the diffusion chamber 5b with the hot water 18, the monomer
A part of Mb diffuses and polymerizes alone or together with the prepolymer in the base material 8, and the above concentration gradient is fixed. The atmosphere in the diffusion chamber 5b is previously evacuated or replaced with nitrogen in order to avoid inhibition of polymerization by oxygen. Further, the ambient temperature is set to, for example, 5 to 90°C, as in the case of known methods. As this temperature increases, the diffusion rate of the monomer Mb increases, but the polymerization rate of the base material itself also increases, which is not preferable. In addition, the time (diffusion time) for contacting the base material with the monomer Mb in the diffusion chamber 5b and the above-mentioned diffusion temperature depend on the refractive index gradient of the desired optical transmission body, that is, the above-mentioned concentration gradient of the monomer Mb. You can decide. However, if this diffusion time is extremely long or the diffusion temperature is too high, the monomer
There is a risk that the concentration gradient of Mb may flatten or become suddenly large near the outer periphery of the base material, making it difficult to obtain a desired refractive index gradient. After diffusing monomer Mb, base material 8 becomes monomer
It is introduced into a microwave irradiation container 6 for heat treatment in order to fix the refractive index gradient obtained by diffusion of Mb, make it a solvent-insoluble component, and improve weather resistance. The synthetic resin light transmitting body 9 thus formed is continuously pulled up by rollers 19 and 20. The microwave irradiation container 6 is provided with a gas introduction pipe 21 and a gas discharge pipe 22, respectively, and nitrogen gas or other inert gas such as helium, argon, etc. is introduced into the container 6 through these pipes 21 and 22. Or it is discharged from the container 6. The microwave irradiation container 6 is provided with a temperature measurement window 23, and a radiation thermometer 24 is disposed adjacent to the temperature measurement window 23. The microwave irradiation container 6 is also provided with a microwave waveguide 25, and this microwave waveguide 25 is connected to a matching box 26.
is connected to a visible microwave transmitter 27.
The microwave transmitter 27 is controlled by a control section 28, to which a measurement signal from the radiation thermometer 24 and a set temperature signal from the temperature setting section 29 are respectively input. Base material 8 with monomer Mb diffused in the diffusion device 5
The polymerization is completed while passing through the microwave irradiation container 6, and the refractive index gradient obtained by the diffusion of the monomer Mb is fixed. The refractive index of the optical transmission body obtained in this way increases or decreases in the radial direction approximately in proportion to the square of the distance from the central axis, depending on the combination of monomer Ma and monomer Mb, as described later. It has a refractive index gradient of This refractive index remains constant without changing in the length direction of the optical transmission body. The monomer Ma to be the raw material of the transparent gel body as the base material in the above examples is a monomer having two or more types of groups among allyl group, acrylic acid group, methacrylic acid group, or vinyl group. can be used. Next, a specific example of monomer Ma will be given. (1) Allyl compounds: Diallyl esters such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, and diethylene glycol bisallyl carbonate; Triallyl esters such as triallyl trimellitate, triallyl phosphate, and triallyl phosphite; Allyl methacrylate, acrylic Unsaturated acid allyl esters such as allyl acids. (2) Compound represented by R ₁ −R ₂ −R ₃ : R ₁ and R ₃ are both vinyl group, acrylic group,
A compound that is a vinyl ester group or a methacrylic group; one of R ₁ and R ₃ is one of the four groups vinyl, acrylic, meccryl, and vinyl ester, and the other is the remaining A compound that is any of the three groups. here
R ₂ can be selected from the divalent groups shown below.

[ka]

【formula】

[Chemical] −CH ₂ CH ₂ O) _n −CH ₂ CH ₂ − (m=0 to 20)

[Formula] −(CH ₂ ) _p (p=3 to 15)

[ka]

(3) A mixture of the monomers (1) and (2) above, or at least one of the five monovinyl compounds, vinyl esters, acrylic esters, and methacrylic esters and the above ( Mixtures with monomers 1) or (2) (or mixtures thereof). Furthermore, examples of the monomer Mb include the following compounds. (Four)

Compound represented by [Formula]: However, X is a hydrogen atom or a methyl group, Y is

【formula】

[Formula] -CH= _CH2 , -( _CH2 )H (l=1-8), i-propyl group,
i-butyl group, s-butyl group, t-butyl group,

【formula】

[Formula] and a group selected from the group consisting of -(CH ₂ CH ₂ O) _p -CH ₂ CH ₃ (p=1 to 6), or -(CF ₂ ) _a -F (a=1 to
6), -CH ₂ (CF ₂ ) _b H (b = 1 to 8), -CH ₂ CH ₂
O・CH ₂ CF ₃ , −(CH ₂ CH ₂ O) _c CF ₂ CF ₂ H (c=
1 to 4), -CH ₂ CH ₂ O・CH ₂ (CF ₂ ) _a F (a=1
~6), _-CH2 ( _CF2 ) _dO ( _CF2 ) _lF (d=1~2,l
=1-4) and Si( _{OC2H5 )3 .} (Five)

Compound represented by [Formula]: However, R ₄ is -(CH ₂ ) _f -CH ₃ (f=0~
2), -(CH ₂ ) _g H (g = 1 to 3),

[Formula] and

〔Effect of the invention〕

As described above, this invention prevents the phenomenon in which the prepolymer in the surrounding area gels and stagnates in the molded tube first, and the oozing liquid becomes a liquid layer seal, so that the diffused substance in the diffusion means is spread inside the molded tube. This has made it possible to stably and continuously manufacture synthetic resin optical transmitters over a long period of time. Next, this invention will be explained with reference to a specific example. Specific example Diethylene glycol bisallyl carbonate (CR-39) in which 3.0% by weight of benzoyl peroxide (BPO) was dissolved as a polymerization initiator was heated at 75°C for 65°C.
Partial polymerization was achieved by heating for a minute to obtain a prepolymer that maintained fluidity just before gelation. The viscosity of this prepolymer is 1015 cps at 20°C, and the above formula (4)
The values of K and n in are respectively 2.57×10 ^-2 cm ²
dyne ^-1 sec ^-1 and 1.21. This prepolymer 7 is put into the extruder 1 of the apparatus shown in FIG.
It was fed continuously at a constant flow rate of 3.0×10 ^-2 ml/min. A temperature gradient was created by flowing hot water 10 at 80°C in the upper part of the jacket 2 and hot water 11 at 64°C in the lower part. Prepolymer 7 gels while passing through tube 3 for about 32 minutes, and
It was molded into a base material 8 of mmφ. This matrix 8 contains 25% by weight of a component insoluble in acetone (reticular polymer portion), 5% by weight of a component soluble in acetone but insoluble in methanol (linear polymer portion), and soluble in both acetone and methanol. It consisted of 70% by weight of soluble components (monomers and low molecular weight prepolymer parts). A sealing liquid 12 of a liquid sealing device 14, which will be explained later, was caused to flow into the jacket tube 4 by a pump 34 at a flow rate of about 30 mm/hr. The sealing liquid 12 flowing through the jacket tube 4 penetrates into the nozzle 13 made of a liquid-permeable porous material.
It exudes from the inner wall of the nozzle and acts as a lubricant between the inner wall of the nozzle and the prepolymer 7 that is being molded. This prevents the prepolymer that has first gelled near the tube wall of the molded tube 3 from staying inside the molded tube 3, and the surface condition is not damaged.
No more breakage. Next, the base material 8 is pulled up by 6.2mm/
It was fed into the gas phase diffusion device 5 at a constant speed of min.
Liquid sealing device 1 below this gas phase diffusion device 5
Silicone oil was used as the sealing liquid 12 in No. 4.
The base material 8 passes through a liquid phase of silicone oil formed in the liquid reservoir chamber 14a of the liquid sealing device 14 due to the silicone oil exuding from the nozzle 13, and then is guided into the diffusion chamber 5b in the gas phase diffusion device 5. Ta. By doing this, the phenomenon that has been a problem in the past can be avoided, namely, the monomer Mb in the diffusion chamber 5b enters through the gap between the base material 8 and the tube 3, and the prepolymer 7 being molded into the base material 8. There was no occurrence of unevenness on the surface of the base material due to diffusion, and therefore no breakage of the base material occurred. The base material 8 sent into the diffusion chamber 5b is passed through an atmosphere containing vapor of 2,2,2-trifluoroethyl methacrylate (3FMA) for about 40 minutes to diffuse and partially polymerize 3FMA. I made it.
3FMA was vaporized in the steam generator 30 and then introduced into the diffusion chamber 5b through the inlet 31.
3FMA vapor was collected from the outlet 33 by the pump 32 and liquefied in the trap.
Since 3FMA was hardly polymerized, it could be used repeatedly. Note that before introducing 3FMA into the diffusion chamber 5b, nitrogen gas was introduced at a flow rate of 1000/min to previously replace the air in the system with nitrogen. The outer tube 5a is divided into three parts, each from the bottom.
Warm water at 75, 80 and 85°C was run. The base material 8 that passed through the diffusion device 5 was introduced into the microwave irradiation container 6 . Set the surface temperature of the base material 8 of the transparent gel object to 110°C using the temperature setting unit 29,
The radiation thermometer 24 measures the surface temperature, and the measurement signal is fed back to the microwave transmitter.
The microwave output was controlled so that the surface temperature of the base material 8 was 110°C. In this way, a synthetic resin optical transmitter 9 with a diameter of 2.5 mm was obtained stably for a long time with a good surface.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an example of a manufacturing apparatus that can be used to carry out the manufacturing method of the present invention, and FIG. 2 is a cross-sectional view showing the main part of FIG. 1. In addition, in the symbols used in the drawings, 1...extruder, 2...heating jacket, 3...forming tube, 4...
...Jacket tube, 5...Diffusion device, 5b...
... Diffusion chamber, 6 ... Microwave irradiation container, 7 ... Prepolymer, 8 ... Base material, 9 ... Synthetic resin light transmission body, 10 ... High temperature water, 11 ... Low temperature water, 12
... Seal liquid, 13 ... Porous nozzle, 14 ...
Liquid sealing device, 24... Radiation thermometer, 27... Microwave transmitter, 28... Control section, 29... Temperature setting section.

Claims (1)

[Claims] 1 Monomer that produces a network polymer Pa with a refractive index of Na
Ma is partially polymerized to form a fluid prepolymer, and this prepolymer is supplied to a long and thin molding tube, and as it progresses through the molding tube, it is continuously molded into a self-shape-retaining base material by heating. rate
Manufacture of a synthetic resin optical transmitter having a refractive index distribution in which a monomer Mb that produces a polymer Pb having a refractive index Nb different from Na is diffused from the surface of the base material to the inside thereof and polymerized. In the method, when molding the base material, a molding nozzle made of a liquid-permeable porous material is provided at the exit portion of the molding tube, and liquid is exuded from the molding nozzle to form the base material and the wall of the molded tube. 1. A method for manufacturing a synthetic resin optical transmission body, characterized in that it prevents the adhesion of , and seals between a base material and a molded nozzle.