JPS6012507A - Manufacture of synthetic resin optical transmission body - Google Patents

Abstract

PURPOSE:To form a desired refractive index distribution extending over a wide range of a base material extending from the center to the outside circumferential part by setting a characteristic value related to a refractive index of a monomer for forming the base material and a monomer diffused in the inside of the base material, to a specified relation. CONSTITUTION:A base material 7 having a self-shape is formed by executing an incomplete polymerization of a monome Ma, a monomer Mb is diffused to its inside, and at least an initial stage of the subsequent heating polymerization is executed in an atmosphere containing a monomer Mc which is the same as the monomer Mb or different from it. In case the monomer Mc which is different from the monomer Mb is used, the monomer Mb in a liquid phase diffusion chamber 9 is not bubbled but used only for a liquid phase diffusion, and a gaseous or fog-like monomer Mc is led into a gaseous phase chamber 13 from a vapor generator, etc. In any case, however, in case a refractive index of a single polymer of the monomers Ma, Mb and Mc is denoted as Na, Nb, Nc, respectively, a combintion is selected so that Nc is also larger than Na in case Nb is larger than Na, and on the contrary, Nc is also smaller than Na in case Nb is smaller than Na.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a synthetic resin optical transmission body having a refractive index distribution.

A transparent rod-shaped body having a refractive index distribution that decreases 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 approximated by equation (1).

(In the formula, n (rl represents the refractive index at the distance r from the central axis, no represents the refractive index at the central axis, and A represents a positive constant.) A light beam meanders through such a transparent rod-shaped body. The period is expressed by equation (2).

L=2 danger...four circles (2).

Furthermore, as approximated by equation (3), if the refractive index distribution increases in proportion to the square of the distance from the center,
The transparent rod-shaped body becomes a light transmission body having a concave lens effect.

(In the formula, n(r) and no are the same as above, and 13
is a positive constant. ] A method for manufacturing a synthetic resin optical transmission body having such a refractive index distribution is disclosed in Japanese Patent Publication No. 52-5857 and Japanese Patent Application Laid-open No. 51-1.
It is described in JP-A No. 6394, JP-A-54-119959, and the like. In the methods described in Japanese Patent Publication No. 52-5857 and Japanese Patent Application Laid-Open No. 51-16394,
First, a crosslinkable monomer Ma that produces a network polymer Pa is initially polymerized from a liquid state to a gel state that has lost fluidity to form a transparent gel-like base material. Next, this base material is immersed in a liquid phase consisting of a monomer Mb different from the monomer Ma to create a concentration gradient of the monomer Mb such that the base material gradually decreases from the surface toward the inside. monomer M to have
Diffuse b. At this time, the monomer Mb is a polymer P having a refractive index different from that of the network polymer Pa.
A monomer that produces b is used.

The monomer Mb is polymerized simultaneously with the diffusion and/or during the heat treatment step after the diffusion, and at this time the polymerization of the monomer Ma is also completed. Japanese Patent Publication No. 52-5857 and Japanese Unexamined Patent Publication No. 51
In the method described in Japanese Patent No. 16394, a synthetic resin optical transmission body having a refractive index distribution is obtained in this manner.

However, in the method described above, the base material is a liquid monomer Mb.
The direct contact between the surface of the base material and the liquid monomer Mb by immersion therein had several disadvantages. for example,
In cases where the diffusion and polymerization of the monomer Mb are carried out simultaneously, the dipping temperature must be relatively high, and the polymerization initiator normally contained in the base material will enter the liquid phase as the dipping time passes. Because of the elution, monomer Mb gradually polymerizes even in the liquid phase and becomes viscous. As a result, when the base material is removed from the liquid phase after diffusion, the viscous layer thus formed remains attached to the surface of the base material. During the heat treatment process, the monomer Mb is leached from the viscous layer and diffused into the base material, causing an increase in undesirable distortion in the refractive index near the outer periphery of the resulting light transmitting body. In order to eliminate such drawbacks, it may be possible to add a polymerization inhibitor that suppresses the polymerization of monomer Mb in the liquid phase, but in this case, this polymerization initiator may inhibit the polymerization of monomer Mb. This causes a new drawback in that it diffuses into the base material at the same time as the diffusion of , inhibiting the completion of polymerization in the heat treatment step.

In addition, in the case of ζ polymerization after diffusion of the monomer Mb, a relatively low immersion temperature is required, but in this case, the diffused monomer Mb evaporates from the outer periphery of the base material during the heat treatment process. , which also causes an increase in undesirable distortion in the refractive index distribution near the outer periphery.

The method described in JP-A-54-119939 is an improvement on the above-mentioned method to avoid distortion of the refractive index distribution near the outer periphery. According to this method, monomer Mb is diffused in a gas phase. That is, the base material is placed in a vapor atmosphere of monomer Mb for a predetermined period of time, and
B is diffused into the base material, and at the same time as this diffusion, a portion of the monomer Mb is polymerized, and finally the polymerization is completed by heat treatment. This method has the following advantages because the base material comes into contact with the gas phase monomer Mb rather than with the liquid phase monomer Mb.

(1) Excess monomer Mb does not adhere to the surface of the base material (therefore, monomer Mb attached during the heat treatment process does not diffuse from the surface of the base material to the inside. Since the heat treatment is carried out at a high temperature, the monomer Mb is polymerized and fixed while diffusing into the base material. Therefore, the monomer Mb does not evaporate from the outer periphery of the base material during the heat treatment process.

Therefore, it is possible to obtain an optical transmission body with little distortion of the refractive index at the outer circumference and having an initial refractive index distribution over a wide range.

(2) By adding a polymerization inhibitor to the liquid monomer Mb that is the source of the vapor of the monomer Mb, polymerization of the monomer Mb in the liquid phase can be prevented. At this time, if a polymerization inhibitor with a low vapor pressure is used, it will hardly vaporize and will not diffuse into the base material, so that polymerization will not be inhibited during the heat treatment process. Furthermore, by adjusting the supply rate of monomer Mb, there is no need to add a polymerization inhibitor, and monomer Mb can be used repeatedly, increasing its recovery rate.

However, this method has the following drawbacks. In other words, when monomer Mb is diffused from the gas phase into the base material, the concentration of monomer Mb in the gas phase depends on the vapor pressure at the gas phase temperature. The types of monomers suitable for proceeding are limited to specific monomers with high vapor pressures. For example, JP-A-51-163
Diethylene glycol bisallyl carbonate (monomer 'Ma) that can be used in manufacturing a synthetic resin optical transmission body having low chromatic aberration by the method of No. 94, and 1,1.3-
In combination with trihydroperfluoropropyl (monomer Mb), the latter has a low vapor pressure and a diameter of 4. The method of JP-A-54-119939 could not be applied because it was difficult to diffuse into the ROM or other base materials.

The present invention overcomes the drawbacks of these prior art technologies while taking advantage of their respective strengths.

We also developed a method for manufacturing synthetic resin optical transmitters that can form desired refractive index distributions over a wide range of the base material from the center to the outer periphery for various combinations of monomers Ma and monomers Mb. This is what we provide.

That is, this invention performs incomplete polymerization of a monomer Ma that produces a network polymer Pa having a refractive index Na to form a base material having self-shape retention, and has a refractive index N different from the refractive index Na.
Synthetic resin having a refractive index distribution, which produces a polymer Pb having a polymer Pb and a monomer Mb in a liquid state, which is brought into contact with the surface of the base material, diffused into the interior thereof, and then heated and polymerized. In the method for producing an optical transmission body, at least the initial stage of the thermal polymerization is performed using a monomer Mc that is the same as or different from the monomer Mb, (a), Nc = Nb (b), Nc (Na and Nb (Na(C), Nc
) Na and Nb) An atmosphere containing a gaseous or droplet-like monomer Me that produces a polymer Pc having a refractive index Nc that satisfies any one of the conditions (a) to (C), which is Na and Nb) The present invention relates to a method for manufacturing a synthetic resin light transmitting body, characterized in that the manufacturing method is carried out in a medium.

According to the manufacturing method of the present invention configured as described above, the monomer Mb, which accounts for most of the monomers diffused into the base material, is not limited to those having a high vapor pressure, and the monomer W is also diffused into the base material. Since it is only necessary to suppress the evaporation of the monomer Mb from the outer peripheral part of the material, there is no need for the material to have a particularly high vapor pressure. In addition, since the heat treatment is performed in an atmosphere containing vapor (gaseous or mist-like) of the monomer Mc (which may be the same as the monomer excitation), the refractive index distribution near the outer periphery of the base material is distortion can be removed or avoided.

Next, an embodiment 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.

First, the monomer Ma is prepolymerized to produce a viscous fluid (prepolymer) that maintains fluidity just before gelation. Put this prepolymer (1) into an extruder (2),
Extrude continuously while cooling with cooling water.

Here, the prepolymer has the general formula: % Formula % (4) (where D is the shear rate, σ is the shear stress, and K is the plastic power law), and the value of n at 20C is 1.10 or more. It is desirable to indicate. The reason is explained below.

When a fluid similar to a Newtonian fluid such as a monomer or a low-viscosity prepolymer is introduced into a long and thin tube and is heated and polymerized while passing through the tube, the heat is applied from the outside of the tube, so Polymerization proceeds from the peripheral region, 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 velocity difference between the peripheral region and the central region increases. becomes even larger. In the end, 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 polymerizing.

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 the Bingham fluid. Bingham fluid is a case where n; ω 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. Also, the flow velocity of the fluid near the periphery near the inner wall of the pipe does not change much depending on the value of n.In fact, the larger n is, the greater the flow velocity is, but the closer n approaches 1, the faster the flow velocity near the center becomes. grow bigger,
As a result, the difference in flow velocity between the peripheral region and the central region becomes large, and the parabola of the velocity distribution becomes sharp.

From this point of view, it is preferable to prepolymerize the monomer Ma as described above to form a viscous fluid in which the value of n is 1.10 or more before feeding it into the pipe.

That is, if the value of n is less than 1.10, 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. In this case, if the flow rate is extremely reduced, the base material will not be formed, but productivity will be poor and this is not practical. Further, more preferably, the value of n is at most 1.50. This is because if the value of n is too large, it will become difficult to push into the pipe or the base material will become non-uniform, causing problems.

Note that the value of K and the value of n in the above equation (4) can be determined using a viscometer (for example, a rotational viscometer). In other words, the rotational speed of the viscometer (this determines D)
After changing σ and measuring each σ, plot these on a graph and calculate the values of K and n.

The extruded prepolymer (1) is then continuously introduced into a Teflon tube (4) passing through a heating jacket (3), such as a brass block. This Teflon tube (4) may have a circular cross section and a diameter of 1 to 20 mm. Here, prepare the Teflon tube (4) in advance.
Insert the lower end of the stainless steel pipe from above into the
Since the tip of the prepolymer (1) gels while in contact with the lower end of the stainless steel tube, the lower end of the stainless steel tube and the tip of the prepolymer (1) are integrally connected. When the stainless steel tube is pulled up by a pulling device at the same speed as this push-out speed, the prepolymer accompanying it becomes a light transmitting body and is produced continuously and without stagnation within the device during the entire manufacturing process. It comes out. The heating jacket (3) has relatively high temperature hot water (5) on the top thereof;
Hot water (6) at a lower temperature is supplied to the lower part, and the Teflon tube (4) is heated with a temperature gradient such that the temperature gradually increases from the lower part to the upper part. Then, while passing through the Teflon tube (4), the prepolymer (1) is polymerized and gelled by heating, and this gelled prepolymer becomes the base material (7). The heating rate during this thermal polymerization is preferably 0.1 to 10 C/min. When heated under the above-mentioned temperature gradient, both the polymerization of the prepolymer (1) and the accompanying increase in viscosity proceed gradually, so the prepolymer (1) is heated while being maintained in a fluid state similar to Bingham fluid. (]) can be made to flow. As a result, it becomes possible to continuously form a base material (7) having a uniform composition in the radial direction. Note that Teflon tubes are particularly useful here because they have low friction with the prepolymer (1) and the base material (7), but tubes made of other resins or metals may also be used.

In this way, the Teflon tube (4) within the heating jacket (3) generates a gel-like base material (7) that has almost lost its fluidity and has self-shape retention. This matrix (7) preferably contains from 5 to 90% by weight, more preferably from 10 to 50% by weight, of components insoluble in acetone, ie, parts of flocculent polymers. If this component is too small, the fluidity becomes high, and if it is too large, the diffusion rate of the monomer Mb becomes too slow in the subsequent wave measurement process, which is not preferable.

Subsequently, the base material (7) is fed into the diffusion device (8).

The lower part of this diffusion device (8) is a liquid phase diffusion chamber (9), and liquid monomer Mb is supplied to this liquid phase diffusion chamber (9) from an injection port 00). This monomer Mb is stored in the liquid phase diffusion chamber (9), and its surplus is discharged from the discharge port (11). While staying in the liquid phase diffusion chamber (9), the monomer Mb diffuses into the base material (7) almost to its center, and increases continuously in approximately proportion to the square of the distance from the central axis. Such a concentration gradient of the monomer Mb is formed in the base material (7). In addition, a bubbler Cl21 is arranged in the monomer Mb of this liquid phase diffusion chamber (9), and the vapor of the monomer Mb is generated by generating bubbles of ♀ elementary gas from this bubbler 0z. generate. In this way, the vapor of the monomer Mb in the form of gas or droplets rises to the gas phase chamber 03) which is connected to the upper part of the liquid phase diffusion chamber (9) and fills this gas phase chamber θ. gas phase! (In 131, an atmosphere containing vapor of monomer Mb is formed. Monomer Mb is recovered from the exhaust port (■η) by a vacuum pump (not shown). The liquid phase diffusion chamber (9) It has been replaced with nitrogen in advance and is hidden to prevent inhibition of polymerization by oxygen.

The base material (7) in which the monomer Mb has been diffused is thus introduced into the gas phase chamber 0 filled with an atmosphere containing the monomer Mb vapor. The gas phase chamber 03) is heated by hot water flowing through the outer tube 0(a) surrounding it. While staying in this gas phase chamber 03), a part of the diffused monomer Mb polymerizes alone or with the monomer Ma or prepolymer remaining in the base material (7), and As a result, the concentration gradient of monomer Mb is fixed within the base material (7).

At this time, since the base material (7) is surrounded by an atmosphere containing the vapor of monomer Mb, evaporation of monomer Mb from the outer periphery of the base material (7) into the gas phase is suppressed. be done.

As a result, it is possible to produce an optical transmission body in which distortion in the refractive index near the outer periphery is almost absent or exists only in a narrow range. The monomer Mb should be contained in a small amount in the gas phase (at least 20 g or more of its saturated concentration) during punching. If the inside diameter is large, the monomer Mb is diffused from the gas phase into the base material simultaneously with the thermal polymerization of the monomer Mb.

The temperature of the monomer Mb in the liquid phase diffusion chamber (9) can be adjusted to such an extent that the monomer Mb
has a relatively high vapor pressure and must be maintained at a value that allows it to diffuse into the base material, for example, it is set at 5 to 9°C.

As this temperature increases, the diffusion rate of monomer Mb increases, but the polymerization rate of the base material itself also increases, and monomer Mb polymerizes in the liquid phase and becomes viscous. Undesirable. Further, the time for which the base material is allowed to stay in the diffusion chamber (8) (diffusion time) and the above-mentioned diffusion temperature are determined by the refractive index gradient of the optical transmission body to be obtained, that is, the above-mentioned concentration gradient of the monomer Mb. It will be done. However, if this diffusion time is extremely long or the diffusion temperature is too high, monomer M
There is a possibility that the concentration gradient of b becomes flat or suddenly increases near the outer periphery of the base material, making it impossible to obtain a desired refractive index gradient.

In this embodiment, the monomer Mb in the liquid phase diffusion chamber (9) is used to form the atmosphere in the gas phase chamber (3). In other words, although the case where the monomer Mc is the same as the monomer Mb is shown, the monomer Me may be different from the monomer Mb or a mixture thereof, or it may be different from the monomer Mb. It may also be a mixture with other monomers.

When the gaseous or atomized monomer Mc, which is completely different from the monomer Mb, is contained in the gas phase, the gas phase chamber (13) and the liquid phase diffusion chamber (9) are partitioned, and the liquid phase The monomer Mb in the diffusion chamber (9) is used only for liquid phase diffusion without bubbling. Then, a gaseous or mist-like monomer alcohol is introduced into the gas phase chamber (I3) from a steam generator or the like. Further, when the vapor of monomer Mb is filled in the vapor phase chamber in the same manner as in the example, and the vapor of another monomer Mc is introduced into the vapor phase chamber, the vapor of monomer Mb is filled in the vapor phase chamber. The system is a mixture of the monomer Mc and the monomer Mc vapor.

In such a case, even a compound in which the monomer Mc is a gas at room temperature can be used. However, in any case, the refractive index of the monopolymer Pa%Pb%Pc of 4a, Mb and Me is changed to Na, Nb, respectively.
%Nc, if Nb is larger than Na, N
If c is also larger than Na and conversely Nb is smaller than Na, the desired refractive index distribution cannot be obtained unless a combination is selected in which Nc is also smaller than Na.

After heating and polymerizing in the gas phase chamber 03), the base material (7) is further led to a heat treatment tube (151) which is purged with nitrogen to complete the heating polymerization. However, it is also possible to form a temperature gradient by increasing the temperature of this heater (161) stepwise from the bottom to the top of the device. Mb vapor may be introduced.

The refractive index of the optical transmission body θ obtained in this way increases continuously in the radial direction approximately in proportion to the square of the distance from the central axis due to the combination of t monomer Mal and monomer Mb, as will be described later. Alternatively, it has a decreasing refractive index gradient. This refractive index does not change in the length direction of the optical transmission body and remains constant.

In the embodiments described above, the step of forming the base material, the monomer M
Since the process of diffusing b and the heat treatment process are all carried out continuously, it is possible to manufacture an optical transmission body with uniform characteristics and constant quality. However, like the conventional example mentioned at the beginning, the manufacturing method of the present invention is also applicable to a batch method in which each step is performed separately.

In the method of this invention, a monomer that can be polymerized to produce a transparent network polymer Pa having a refractive index of Na is used as the monomer Ma, but this monomer is a single monomer. It may be a monomer or a mixture of multiple types of monomers.

Such monomers Ma each have two or more groups containing double bonds, such as allyl groups, acrylic acid groups, methacrylic acid groups, and vinyl groups, or two or more of these groups.
Monomers having more than one type at the same time are preferred. Next, specific examples of monomer Ma will be given.

(1) Allyl compounds and mixtures thereof.

Diallyl esters such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diethylene glycol bisallyl carbonate; triallyl trimellidate,
Triallyl esters such as triallyl phosphate and triallyl phosphite; unsaturated acid allyl esters such as allyl methacrylate and allyl acrylate.

(2) A compound represented by R1-R2-R3 and a mixture thereof. A compound in which both R1 and R3 are a vinyl group, a 1-acrylic group, a vinyl ester group, a monoacrylic group, or a methacrylic group; R1
and a compound in which either one of R3 is a vinyl group or one of the four groups, and the other is one of the remaining six groups. Therefore, R2 is 2 shown below.
can be selected from among the valence groups.

I(C- H3-(CI(2C)120+-C112CH2-(m=0
~20) 1 σ? H,)-(p=3-15) (3), a mixture of the monomers (1) and (2) above, or five types of monovinyl compounds, vinyl esters, acrylic esters, and methacrylic esters A mixture of at least one of the above and the monomer (1) or (2) (or a mixture thereof).

In this invention, the monomer Mb is selected from a monomer which forms a transparent polymer Pb having a refractive index Nb greater than or less than the above-mentioned refractive index Na when it is polymerized. This monomer Mb may be a single monomer or a mixture of multiple types of monomers. The polymer Pb may be either a network polymer or a linear polymer. When the refractive index Nb is smaller than the refractive index Na, the resulting optical transmission body has a convex lens effect with a refractive index distribution as expressed by the above equation (1). Conversely, when the refractive index Nb is larger than the refractive index Na, an optical transmission body having a concave lens effect can be obtained with the refractive index distribution expressed by the above equation (3). The difference in these refractive indexes (lNa-Nbl)
is preferably 0.005 or more; if this difference is too small, the desired refractive index gradient cannot be obtained. In addition, monomer M
b preferably has a relatively high vapor pressure, especially when diffused in the gas phase, for example preferably has a saturated vapor pressure higher than 5 mm Hg at the diffusion temperature. Examples of such monomeric MbO include styrene, methacrylates, acrylates, vinyl acetate, vinyl chloride, acrylonitrile, butadiene, and mixtures thereof.

Preferred examples of the combination of the network polymer Pa and the monomer Mb of the present invention include those suitable for producing a light transmitting body with low chromatic aberration as described below. First, in the case of Na) Nb, diallyl phthalate polymer - methyl methacrylate, diallyl phthalate polymer - a mixture of methyl acrylate and methyl methacrylate, diallyl isophthalate polymer - methyl methacrylate, diallyl phthalate polymer and Copolymer with styrene - methacrylic acid ester, copolymer with diallyl isophthalate and styrene - acrylic acid ester, copolymer with divinyl phthalate and divinyl benzoate - methacrylic acid ester, divinyl isophthalate and vinyl benzoate These include copolymers with vinyl benzoate and diallyl isophthalate and methacrylic esters.

Examples of Na (Nb) include diethylene glycol bisallyl carbonate polymer-styrene, diethylene glycol bisallyl carbonate polymer-diallyl isophthalate, and the like.

In addition, the following combinations of monomers Ma and monomers Mb are particularly suitable for manufacturing a synthetic resin optical transmission body with low chromatic aberration.

(a) Diethylene glycol bisallyl carbonate as Ma, or a mixture thereof with diallyl phthalate, diallyl isophthalate, vinyl benzoate or styrene (provided that the amount of diethylene glycol bisallyl carbonate in this mixture is 50% by weight or more) (more preferably 70% by weight or more).

As Mb, compound (A): CH2=C-COOY
) [wherein, X is a hydrogen atom or a methyl group, Y is a phenyl group, a methylphenyl group, a vinyl group
20) Represents a group selected from the group consisting of CH3 (z=1-3). ] A compound represented by or a mixture thereof.

(b) Diethylene glycol bisallyl carbonate as Ma, or a mixture thereof with methyl acrylate, ethyl acrylate, n-butyl methacrylate or t-butyl methacrylate (however, the amount of diethylene glycol bisallyl carbonate in this mixture is 10
(Preferably, it is at least 100% tS). As Mb, compound (B) CH2= C-C00Y ・・・・・・・・・・・・(
B) [In the formula, X is a hydrogen atom or a methyl group, and Y is -(CF2)iF (i = 1-6), -CI4
2 (CF2)jH (j=1-s), - mark, CH20CH
2CF3, - (CH,,CH20)kCF2CF2H
(k = 1~4), -(CH2CH20CH2(CF
2) NoF (l=1 to 6), -CH2(CF2) 0(
CF2) represents a group selected from the group consisting of F (m = 1 to 2, n = 1 m n to 4). ] or a fluorine-containing alcohol ester of methacrylic acid or acrylic acid, or a fluorine-containing alcohol ester of methacrylic acid or acrylic acid;
OC2H5) S compound (C1゜(C), monomer Ma is a mixture of diethylene glycol bisallyl carbonate and the above compound (13+t)(q) (however, the amount of diethylene glycol bisallyl carbonate in this mixture is 10]i (It is preferable that the amount is at least 100%)
. The above compound (A) as monomer Mb.

The monomer Me of this invention is the same or different from the monomer Mb, and produces a polymer Pc having a refractive index Nc. The monomer Mc may be either a single monomer or a mixture of multiple types of monomers, and the monomer Nb (!:l, It can be used as body Mc.Those with particularly high vapor pressure are suitable.

Next, a specific example of this invention will be shown.

Specific example 1 3. As a polymerization initiator. (wt% benzoyl peroxide (
Diethylene glycol bisallyl carbonate (CR-59) in which BPO) was dissolved was prepolymerized by heating at 75 Hayashi C for 65 minutes to obtain a prepolymer that maintained fluidity just before gelation. The viscosity of this prepolymer is 20C
is 1015 cp, and the values of K and n in the above equation (4) are each 2.57x10 cm dyne
sec and 1.21 Te Atsuta. The conoprepolymer (1) is placed in the extruder (2) of the apparatus shown in Figure 1, and the Teflon tube (
4) (Diameter 4mm, length 200mm) 6, 3X
It was fed continuously at a constant flow rate of i Oml/min. The heating jacket (3) has 78'C hot water (
5) A temperature gradient was created by flowing hot water (6) at 58'c in the lower part. Teflon tube (4
) for 40 minutes, the prepolymer (1) gelled and was molded into a base material (7) with a diameter of 4 mm. This base material (7) is acetone-insoluble component (reticular polymer part) 2
5% by weight of components soluble in acetone but insoluble in methanol (the linear polymer portion), and 70% by weight of components soluble in both acetone and methanol (the monomer and the low molecular weight prepolymer portion). Ta.

Then, the base material (0.25 cr by a force pulling device)
It was introduced into the diffuser (8) at a constant speed of VI minutes. In the liquid phase diffusion chamber (9), 1.0711% of methacrylic acid-1,1,3-rehydrofluoropropyl (dFMA) was added.
The flow rate was constant at J/min. This 4FMA was used without adding a polymerization inhibitor. Also, during this JFMA, 2
By bubbling nitrogen at a flow rate of 00m11 minutes,
Generate 4FMA of steam and move the gas phase chamber (131 to 4F
Filled with MA vapor. The temperature of the liquid phase diffusion chamber (9) is 70
C, and the gas phase chamber 03) was heated by flowing hot water of 80 C through the outer tube. The 4FMA vapor was collected by a vacuum pump at a flow rate of 8001 nl/min and liquefied in the trap. The liquefied 4FMA and the 4FMA flowing out from the liquid phase diffusion chamber a9 were hardly polymerized and could be used repeatedly as they were. Note that 1. Nitrogen gas was introduced at a flow rate of oomty for nitrogen replacement.

The base material (7) is placed in the liquid phase diffusion chamber (9) for about 5 minutes, and the vapor phase chamber 0:
Diffuse JFMA while staying in 1 for about 30 minutes,
A part of it was polymerized by heating.

The base material (7) that had passed through the diffusion device (8) was then fed into a heat treatment tube that was purged with nitrogen. This heat-treated tube (+4) is heated sequentially from the bottom by the heater (6) to 9 D C, 1
10tr.

It was heated to 120r and 130C to form a temperature gradient.

The base material was heat treated in this heat treatment tube for 6 hours to complete polymerization.

From the rod-shaped bodies having a diameter of 4M that were continuously manufactured in this manner, a rod-shaped convex lens having uniform optical performance, that is, a desired light transmission body was obtained. This rod-shaped body is an optical transmission body in which the value of A in the above formula (1) is 2.22 x 10 mm,
The period L of the light flux that meanders through this rod-shaped body (Equation (2)
)] was 42.5 mm.

Moreover, since this rod-shaped body had a refractive index distribution expressed by the formula (1) almost up to the outer periphery, there was no need to shave off the periphery. moreover.

The evaluation value as a convex lens and the numerical aperture NA were also large at 045.

Specific Example 2 Ethylene glycol dimethacrylate (EDMA) in which 0.10% by weight of BPO and 0.50% by weight of carbon tetrabromide (CBr4) were dissolved was heated to 50% by weight at 45C under nitrogen atmosphere.
Viscosity at 20C is 930 cp after heating for minutes.

K=3.23 x 10 cm dyne sec,
and n=1.19 (7) prepolymers were obtained.

The obtained prepolymer (1) was put into an extruder (2) in the same manner as in Example 1, and then hot water at 60'C (5
), Teflon tube (inner diameter 4 mm, length 96 mm) passing through the heating jacket (3) in which 30 tr of hot water (6) was flowed at the bottom (4) of 6.0X10
It was fed continuously at a constant flow rate of 1 ml/min. While passing through this Teflon tube (4), the prepolymer (1
) gelled to form a transparent cylindrical base material (7 mm in diameter).
) was molded. This base material (7) contains 15.5% by weight of a component insoluble in acetone (reticular polymer portion) and 0.5% by weight of a component soluble in acetone and insoluble in methanol (linear polymer portion).
3% by weight and 84.2% by weight of components (monomers and low molecular weight prepolymers) soluble in both acetone and methanol.

This base material (7) was subsequently fed into a liquid phase diffusion chamber (9) into which 4FMA was injected at a constant flow rate of 1.0 ml/min.

The temperature of this liquid phase diffusion chamber (9) was 6Or. While staying in this liquid phase diffusion chamber (9) for about 5 minutes, dFMA was diffused into the base material (at a depth of 24 m).
m), 4FMA is evaporated by bubbling nitrogen at a flow rate of 200ml/min, and the gas phase chamber (13) is
Filled with FMA vapor. Furthermore, this 4FMA vapor was collected at a flow rate of 8 [IQml/min]. The gas phase chamber 03) was heated with 65r hot water flowing through an outer tube (72 mm in length). The base material (force) was retained in this gas phase chamber Q3 for about 15 minutes.

After 4FMA was diffused and partially polymerized, heating polymerization was completed by introducing force into the base material (heat-treated tube αa). This heat-treated tube was heated to 65 r and 70 C using a heater.

A temperature gradient was created by heating to 85C and 100C. In this way, desired rod-shaped light transmitters could be continuously manufactured. In this optical transmission body, the radius of the portion having the refractive index distribution is 1.68 mm (69% of the whole), and A=3.03×10 mm.

n=36.1 mm. Also, the center diameter is 2.7 m.
The part m was a rod-shaped convex lens with a numerical aperture NA=0.36.

[Brief explanation of drawings]

FIG. 1 is a longitudinal 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 partially enlarged view of the manufacturing apparatus shown in FIG. In addition, considering the symbol t used in the drawings, (1)... Prepolymer (2)
・・・・・・・・・・・・Extruder (3)・・・・・・
・・・・・・Heating jacket (4)・・・・・・・・・・・・
・・Teflon tube (7)・・・・・・・・・・・・
Base material (8)... Diffusion device (9)...
......Liquid phase diffusion chamber QO)...
... Gas phase chamber α ... Heat treatment tube - ... Light transmission body. Agent Souvenir Katsu〃 Yoshio Tsunekako〃 Toshiki Sugiura Figure 1↑ 1g 77'/ //7 Japanese Patent Publication Sho GO-125 (17 (10) Figure 2, / Pusou", 7

Claims (3)

[Claims] (1) Monomer M that produces a network polymer Pa with an A refraction index of Na
The monomer Mb in a liquid state is formed by incomplete polymerization of a to form a base material having self-shape retention, and produces a polymer Pb having a refractive index Nb different from the refractive index Na, and is in a liquid state. In a method for manufacturing a synthetic resin optical transmitter having a refractive index distribution, which is brought into contact with the surface of a base material and diffused into the interior thereof, and then heated and polymerized, at least the initial stage of the heating polymerization is performed using a monomer. Monomer Me that is the same as or different from the body Mb
, (al, Nc = Nb (b), Nc (Na and Nb (Na(C), Nc
:> Na and Nb) Na (a) to (C)
A synthetic resin optical transmitter characterized in that the process is carried out in an atmosphere containing a gaseous or mist-like monomer Mc that produces a polymer Pc having a refractive index Nc that satisfies any one of the following conditions. Production method. (2), the monomer Mc is at least 20% of its saturation concentration;
The method for manufacturing a synthetic resin light transmitting body according to claim 1, wherein the amount of the synthetic resin light transmitting body is contained in an amount corresponding to . (3) The method for manufacturing a synthetic resin optical transmission body according to claim 1, wherein the monomer Mc is the same as the monomer Mb.