JPS60103312A - Production of near parabolic plastic body - Google Patents

Abstract

PURPOSE:To obtain easily a titled resin body by swelling a circular columnar transparent polymer contg. an epoxy resin then diffusing low mol. compds. which react with the epoxy group and forms the polymer having the refractive index lower than the refractive index of the polymer into the polymer and bringing said compd. into reaction with said polymer. CONSTITUTION:A circular columnar transparent polymer having an epoxy group (e.g.; beta-methyl glycidyl methacrylate polymer) is dipped in a swellable liquid (e.g.; ethylene glycol) which satisfies the equation I (V0 is the volume of the polymer before dipping; V is the volume of the polymer when dipped and swollen until the content of the liquid in the polymer attains roughly a specified value) and is swollen to a prescribed volume. Then >=2 kinds of low mol. compds. (e.g.; the formula II, the formula III) which have reactivity with the epoxy resin and form the polymer having the refractive index lower than the refractive index of the polymer are diffused into the polymer and are brought into reaction therewith and are dried, by which the intended near parabolic plastic body is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an improved light-focusing synthetic resin body.

As a converging light transmitting material, a glass fiber material in which the refractive index gradually decreases from the entire central axis toward the surface has already been proposed in Japanese Patent Publication No. 47-816. However, such a converging light transmitting body made of glass has problems in that it has low productivity, is expensive, and has poor flexibility.

In contrast to such a convergent optical transmitter made of glass, a method has been proposed for manufacturing a convergent optical transmitter made of synthetic resin that is highly productive and has excellent flexibility. These synthetic 4tt4 resin focusing transmitters can be roughly classified into (1) 'I
A neon bridge polymer is a synthetic resin body called V, in which the concentration of metal ions changes continuously from the central axis toward the surface (Japanese Patent Publication No. 47-26913), (2) different refractive index of the cover. A synthetic resin body made from a mixture of two or more transparent polymers is treated with a specific solvent to partially dissolve and remove at least one of the constituent components of the synthetic resin body. (Tokuko Sho 47-2805)
(No. 9), (3) Two types of refractive index n seven polymers were created by devising a polymerization method to create a continuous refractive index distribution from the surface to the inside (Special Publication Publication No. 1973-
30301), (4) From the surface of the crosslinked subaggregate, a monomer with a refractive index lower than that of the aggregate is diffused from the surface to the inside, and the 7Vi content of the monomer is arranged so that it changes continuously. - Polymerized to give a refractive index distribution (Special Publication No. 52-5857, Samurai Publication No. 56-
(No. 37521), and (5) diffuse and react a low-molecular compound with a refractive index lower than that of the N polymer from the narrow surface of the polymer with high reactivity to continuously increase the refractive index V from the surface to the interior. A device designed to allow distribution (Special Publication Publication No. 57-2)
No. 9682) etc. Among these methods, methods (1) to (4) are difficult to manufacture optical transmission bodies with high light focusing properties, and it is extremely difficult to specify manufacturing conditions to improve light focusing properties. , or even if conditions for high 1-light-year flux are found, reproducibility is not necessarily obtained, and these manufacturing methods each have their own problems as an industrialization technology. These methods (1) to (4) Compared to the method (5), the method (5) has the advantage that the conditions for forming the refractive index distribution can be selected from a wider range, and that it can be obtained with relatively high reproducibility.

However, the production conditions described in this invention, that is, the method in which the reactive monomer is directly immersed in a reactant having a refractive index lower than that of the polymer, or in a diluted solution of the reactant, do not allow the production of polymers. In many cases, the diffusion behavior of low-molecular substances into the interior does not match the formation conditions of the refractive index distribution that degrades the light focusing property (l-boss). In order to set the conditions for the optimum refraction amount distribution, it is extremely difficult to select the conditions in a method in which the temperature and concentration of the processing solution are changed over time.

In order to solve these problems in forming the refractive index distribution, the present inventors have made extensive studies, and by applying the method shown below, the desired refractive index distribution can be easily and easily achieved. He discovered that it was possible to obtain a polymer with gold-like properties, and completed his invention.

That is, the gist of the present invention is to immerse a cylindrical transparent polymer k (1) having an epoxy group in a titrating swelling liquid to swell it to a predetermined volume.
[having reactivity with an epoxy group] ~, and reacting with the polymer, the refractive index is lower than that of the polymer) 01 refractive index total M A is diffused and reacted inside the polymer, and then dried and simmered in the first step, which is the sign of IP!,?U'0 Focused synthesis+;
0 1.1 ≦--≦ 3.0 (1) [In the formula, vo is 11, Sugi 4-month 1 pickled in raw liquid 011
The volume of the polymerized i book, ■ is the i + 7i, and the body Vr - tun f1
The volume of the 8C polymer immersed and swollen in 1, which is equivalent to almost the entire volume of liquid in the body, is shown. ] Here, the volume (V) of the polymer at which the liquid content within the polymer becomes almost constant is defined as the degree of swelling (TE) of the columnar polymer after immersion that fluctuates within V5 per hour. The swollen polymer does not exist at the boundary surface 75 due to liquid diffusion within the width and when visually observed, it has a volume in a state where equilibrium swelling occurs.

In this way, by pre-swelling the polymer before reacting it with a low-molecular compound, it has become possible to easily form a refractive index distribution that exhibits high light focusing properties. The degree of swelling has a close relationship with the type of low-molecular compound to be reacted in the next step, especially the molecular size. Molecules with a large molecular size will diffuse, and the degree of swelling of the polymer before reaction will increase. There is a need.

If the swelling degree (-) of a cylindrical transparent polymer containing epoxy groups when immersed in a total swelling liquid is less than 1.1, the epoxy groups will be removed in the next step. When immersed in a dilute solution containing a low-molecular compound that is reactive and has a total refractive index lower than that of the polymer, the diffusion rate of the low-molecular compound into the polymer becomes too slow, resulting in production Not only does sex significantly decrease,
Reactions occur preferentially at the polymer surface layer, making it difficult to form a refractive index distribution with a continuous VC change from the surface toward the center, which is necessary for image transmission.

On the other hand, if the swelling degree (-H) value when a cylindrical transparent polymer containing an epoxy group is immersed in a liquid is greater than 50, the swelling degree is too steep and the refractive index distribution is formed. After drying, the polymer may stretch due to its own weight, wrinkles may appear on the surface due to shrinkage, and depending on the conditions, the polymer may whiten or crack.

Therefore, when a polymer is immersed in a liquid to swell, the degree of swelling needs to be set within a range that satisfies equation (1).

However, in order to provide a refractive index distribution that exhibits high light focusing properties, it is necessary not only to control the degree of swelling described above, but also to take measures to address the problems described below. That is, a cylindrical transparent polymer containing an epoxy group that has been swollen to the extent that formula (1) is satisfied is used to form a polymer that has a reactivity with the epoxy group and has a refractive index lower than that of the polymer upon reaction. When the cylinder is immersed in a dilute solution containing a low-molecular-weight compound that generates coalescence and reacts with the low-molecular compound, as the low-molecular compound reacts with the epoxy group, the epoxy groups involved in the reaction near the surface layer of the cylinder are For example, applied optics1
Volume 9, page 1099 (19804E) VC is listed.
The deviation of the refractive index distribution from the theoretical refractive index distribution formula of a rod-shaped lens becomes large near the surface layer of the rod9, resulting in a difference in light focusing between the middle part of the rod and the surface part of the rod. Light focusing performance deteriorates.

In order to prevent such a decrease in light focusing performance, it is necessary to correct the deviation of the refractive index distribution from the ideal distribution due to the decrease in the relative reaction probability of the surface layer that occurs as the reaction progresses.

As a solution to this problem, at least two low-molecular compounds that are reactive with epoxy groups and that react to produce a polymer with a refractive index lower than that of the polymer are used to create a swollen circle. When a columnar polymer is immersed in a reaction solution, the decrease in the refractive index of the polymer after the reaction of a low-molecular compound with a high diffusion rate into the polymer is relatively small compared to a low-molecular compound with a low diffusion rate. In some cases, the swollen cylindrical polymer is immersed in a mixture of low-molecular-weight compounds for a suitable amount of time to react, or in some cases, a reaction solution containing a mixture of low-molecular-weight compounds with different concentrations is used. It is possible to create a total of two or more types of cylindrical polymers and react them by immersing them in order from a low concentration solution to a high concentration solution (for an appropriate amount of time).

As a specific example of the transparent polymer containing an epoxy group used in the present invention, '''C is at least one monomer selected from glycidyl acrylate, glycidyl methacrylate, β-methylglycidyl acrylate, and β-methylglycidyl methacrylate. Other monomers such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenyl methacrylate, styrene, α
- Copolymers with methylstyrene, trifluoroethyl methacrylate, hexafluoroisopropyl methacrylate, pentafluoropropyl methacrylate, ethylene glycol dimethacrylate, pentaerythritol diacrylate, trimethylolpropane triacrylate, etc., or glycidyl methacrylate, β-methylglycidyl methacrylate Examples include homopolymers of Among these, polymers containing β-methylglycidyl methacrylate as the main component have relatively good thermal stability of the epoxy group, high transparency, and a relatively low secondary transition point (approximately 75 ℃), which makes it the most preferable.

The amount of epoxy groups contained in the polymer is not particularly limited, but it is related to the difference in refractive index between the polymer surface and the shell, and the amount of epoxy groups contained in the polymer is related to the large numerical aperture. The ratio of 1 in 11 monomers contained is 10 in 1vLit body morti.
If it is less than a molar level, the transmission rate will be low and only a small field of view can be obtained. Therefore, from a practical point of view,
The epoxy group-containing monomer is preferably contained in the polymer in an amount of 10 mol or more, preferably 40 mol or more.

The cylindrical transparent polymer containing epoxy groups used in the present invention is produced by bulk polymerization. The method of shaping into a cylindrical shape is to make the inner diameter of the tube as uniform as possible,
A mixture of a monomer or a partially polymerized product and a polymerization initiator is placed in a cylindrical container holding a perfect circle, and heated or heated. Examples include a method in which 11N is joined together, and a method in which a resin plate manufactured by a cast polymerization method using two tempered glass plates is completely cut and machined into a cylindrical shape. Suitable examples of the cylindrical container include a fully lengthened peelable glass tube, a cylindrical tube made of polypropylene or polyethylene, and a cylindrical tube made of polytetrafluoroethylene.

An inner diameter of the cylindrical tube of about 0.5 to 10 mm is suitable for the cylindrical transparent polymer used in the present invention.

As the polymerization initiator, commonly used thermal polymerization initiators such as azobisisobutyronitrile, penzoyl peroxide, lauryl peroxide, etc., photopolymerization initiators,
For example, benzoin alkyl ether and the like can be used. Two or more of these polymerization initiators may be used in combination.

In addition, when producing a cylindrical transparent polymer, a method for minimizing air bubbles generated in the polymer is to use a partially polymerized product under pressure and change the polymerization area ff for 1 hour (IS
However, the polymerization conditions must be appropriately selected depending on the type and size of the cylindrical tube used.

Specific examples of the liquid used for swelling the epoxy group @ repolymer used in the invention include methanol, ethanol, ゛robanol tyrene glycol, and these alcohols, methyl acetate, ethyl acetate, Examples include, but are not limited to, mixed solvents with toethyl ether such as methyl ethyl ketone, methylal, anisole, and ethylene glycol dimethyl ether, inflovir ether, butyl ether, and the like.

Specific examples of low-molecular compounds that are reactive with epoxy groups and have a refractive index lower than that of the polymer used in the present invention include fluorinated compounds represented by the following general formulas [1] to [IV]. Carboxylic acid, a fluorinated carboxylic anhydride represented by the general formula [V] ~ [ ~, and a general formula [rX3 ~ [Xl+
] Fluorinated alcohols, etc., are available.

C11”2r+41 C0OH port] C, F2n+, 0H2000H[1] H(OF20F2 >mC0OH[river] ■I(CF2C
F2) mCH2COoH[■]0n1″'211-1-
I COx[V]CnF2n+1CO1 0n F2 n +l OH2001[■]CnF2n
+, C112C! 0< CnF2n-1-1cl(2o)i [■]H(0F2
0F2), ncl(2o)I [X]I Engineering(0F20F
2) lI]0H2cH20H[Xl]CnF2n-1-
1c)12c)(2of([Kari](General formula [D ~ [X
In I+, 1, n is an integer of 1 to 12, and m is an integer of 1 to 6. ] At least two represented by these general formulas [1] to [X1]
In order to impart sufficient light focusing performance to the polymer in the reaction between a low-molecular-weight compound larger than a persimmon and a cylindrical transparent polymer containing an epoxy group in a swollen state that satisfies the formula (υ′ft) , it is necessary to cause the low molecular compound to undergo a diffusion reaction so as to match as much as possible the refractive index distribution shown by the following theoretical formula (2).

n2(r) = n(OPSec2(gr) (2)
r = distance from the center of the rod to the surface direction g - refractive index distribution constant Therefore, K is suitable for selecting at least two or more reactants, and the diffusion rate in the reactants is high and the refractive index is relatively large. It is necessary to prepare a reaction solution containing a large low-molecular compound and a low-molecular compound with a low diffusion rate and a relatively low refractive index in appropriate proportions. Also, the concentration of the reactant,
Regarding the temperature and pressure of the reaction solution, the swelling PJ degree of the polymer, etc., it is necessary to appropriately select and determine the refractive index distribution of the theoretical formula (2).

If the general formula [13~[ Therefore, the value of n, II); 112
, 6 or less is combined with r'EL, i. −
In addition, a low polymer that has a reactivity with that of the polymer and which reacts to produce a polymer having a refractive index lower than that of the polymer I.
When the f1 and 0 product is a fluorinated alcohol represented by the general formula [1 to [X1lJ], in order to promote the reaction, for example,
9 Clayton, Kotome, 1, edited by Yoshio Tanaka [Epoxy resin, chemistry and technology] Part 3 (published by Detsuka Publishing) (197
3rd year) (ゝ'ICPOX'Y J (BjSINI9
” Ohomlstryand Technology
edited by 01ayton A May
and Yoshio Tanaka, DIGKKER
Basic catalysts such as gold alkoxides and tertiary amines as described in IIJO, ), sulfuric acid, boron trifluoride ethyl ether complex, boron trifluoride methanol complex, carvone A method in which the reaction is carried out in combination with an acid catalyst such as an acid is preferred.

Specific examples of diluents used to satisfy formula (2) when reacting compounds represented by general formulas (1) to [Xll] with a polymer include methyl alcohol, ethyl alcohol, propyl alcohol, Preferred examples include butyl alcohol, ethylene glycol, anisole, ethylene glycol dimethyl ether, and mixtures of these with ethyl ether, propyl ether, butyl ether, etc., but are not limited to these.

After arranging a low-molecular-weight compound that is reactive with epoxy groups with a continuous concentration gradient from the surface of the cylindrical polymer toward the center, when the polymer is taken out of the reaction tank and dried, the reaction solution is After pre-drying under conditions that do not exceed the boiling point of the diluent plus 10°C, the process is followed by two-stage drying at a temperature in the range of 120 to 150°C until almost no diluent remains in the polymer. The method is preferred. The reason is kalpa at high temperatures, intense heating! This is because bubbles are less likely to form in the l1 polymer.

The light-focusing synthetic resin body produced in this manner is cut to the length of the rod, and the cut surfaces are polished before use.

The (°C) focusing synthetic resin body according to the present invention has excellent light focusing properties, so it can be used for rod lenses used in copying machine lens arrays, original fiber coupling elements, optical demultiplexers, line sensors, etc. It is expected to be used in a wide range of applications including G, i, and type optical fibers.

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

The production of the transparent polymer and the evaluation of the degree of swelling and C focusing performance were carried out as follows.

(1) Preparation of cylindrical transparent polymer containing epoxy groups Into a polytetrafluoroethylene tube with an inner diameter of 3 tubes, jγ diameter of 1 tube, and length of 30α, mix stock solution with the composition shown in Table 1. Injected, first stage polymerization 'fr, 2 o'clock Ii:i] in a constant temperature water bath at 70°C, followed by second stage polymerization 112
The process was carried out in an air heating oven at 0° C. for 2 hours to obtain cylindrical transparent polymers a″-c.

Table 1 (2) Evaluation of degree of swelling of cylindrical transparent polymer The degree of swelling is -
A cylindrical polymer is immersed in a glass container made of polished glass with opposing glass surfaces parallel to each other, and the outer diameter (ro) of the polymer before swelling is measured using a cassette meter from a direction perpendicular to the polished glass surface. , by measuring the long grass (to) and the outer diameter (rJ) of the polymer after swelling, the long formula (1),
It was calculated using the following formula.

v r2L VO: expansion 1'i: l ntl polymer volume vor♂lo V: after tt 〃 (3) Original focusing Note IJ Hi's iff value Figure 1 shows the spot size measuring device N that shows the light focusing performance.
This is the explanation factor. The jTh axis of the sample lens (1) coincides with the optical axis (2) of the apparatus. l: Adjust the sea urchin and place the table (
(not shown). ■(θ−NθV −(1”
- converting the output light of (3) into parallel light with a diameter larger than the diameter of the sample lens by a beam expander (4); When this parallel beam is made incident on a sample lens having a total pitch length of 174, a spot image is generated at the other end [IIIV]. Enlarge this image using the magnifying glass (5) Ic, and use the television camera (6)
The spot image (9) is displayed on the screen of the TV monitor (8) via the camera controller (7).

The camera controller has a function of displaying the light intensity distribution at the position of the cursor θ1 on the television monitor 0 screen as a curve Ov. By aligning this cursor 0 with the center of the elephant and obtaining the distribution curve of C, the spot size can be determined.

FIG. 2 is a light distribution curve of a spot image.

The spot size is a distance d''''C where the light m is at the thickest rib 1102.

Example 1 A cylindrical transparent polymer a f was immersed in a swelling liquid consisting of 50 parts by weight of ethylene glycol dimethyl ether and 50 parts of isopropyl ether at 65°C for 13 hours, 14 hours, and 15 hours, and the degree of swelling was measured. t43,1
．． 44 and 1.45, which were almost constant. The sample soaked for 15 hours was mixed with 507 parts by weight of ethylene glycol dimethyl ether, 50 parts by weight of Improvil ether, and 5 parts by weight of Improvil ether.
H-octafluoropentanoic acid, 1 part by weight and Hif 1(-
The sample was immersed in a reaction solution at 65° C. containing 1 part by weight of dodecafluorohebbutanoic acid and reacted for 10 hours, then transferred to methanol at room temperature and allowed to exchange the solvent for 1 hour. This sample was dried in a vacuum dryer at 75°C for 24 hours and then at 120°C for 24 hours.
After drying under reduced pressure for a period of time, the entire resin body with a light focusing property Jb was prepared.

When the BCU focusing performance of this sample was evaluated, the spot size d was 5 μn+.

Example 2 Cylindrical transparent polymer a f When the degree of swelling was measured by immersing it in a swelling liquid consisting of 65° C. ethylene glycol dimethyl ether soMz part and 50 parts by weight of isopropyl ether for 13 hours, 14 hours, and 15 hours, the swelling degree was 1. 45,
It remained almost constant at 1.44 and 1.45. The sample soaked for 15 hours was mixed with 50 parts by weight of ethylene glycol dimethyl ether and 50 parts by weight of Improvil ether II! ,
immersed in a reaction solution at 65°C consisting of 1 piece of hetafluorobutyric acid and 0.5 piece of pentadecafluorooctanoic acid, reacted for 7 hours, then transferred to methanol at room temperature,
The solvent was replaced for 1 hour.

This sample was dried in a vacuum dryer at 75°C for 24 hours, and then for 1 hour.
It was dried under reduced pressure at 20° C. for 24 hours to produce a light-focusing synthetic resin body. When the light focusing performance of this sample was evaluated, the spot size dld was 4.5 μm.

Examples 3 to 9, Comparative Examples 1 to 3 Example 1 except that the swelling condition in the first step and the reaction condition of two or more low molecular weight compounds for lowering the refractive index in the second step are 1. A whole B-C focusing synthetic resin body was prepared under exactly the same conditions as described above, and the light focusing performance was completely evaluated. Table 2 shows the respective conditions and evaluation results of light focusing performance.

GDM: Ethylene glycol dimethyl ether PE
: Isopropyl ether MθOH: Methanol 1ijtOH: Ethanol KtAc: Ethyl acetate b2o: Ethyl ether 8F'PA: 5H-octafluoropenkun 17F
BA: Heptafluorobutyric acid 12FHA: 7H-dodecafluorohebbutanoic acid 15
FOA: heptadecafluorooctanoic acid 3Fl! i
:2,2.2-)Refluoroethanol 3FAA:)Refluoro vinegar rice 8FF :2,2,3,3,4,4,5.5-octafluoropentanol 5FPA : (02F600)2
0,! IFB-BF3: ! lBoron fluoride trifluoroethanol complex

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a spot size measuring device, and FIG. 2 is a light amount distribution curve of a spot image. 1: Sample 3: ] (e-tJθ laser 4: Beam expander 5: Microscope 6: Television camera 7: Camera controller 8: Digital monitor

Claims (1)

[Claims] A cylindrical transparent polymer containing all epoxy groups is immersed in an expandable liquid A that satisfies formula (1) to swell to a predetermined volume of 1, and then the polymer is swollen to a predetermined volume of 1. using at least two types of low-molecular-weight compounds that have a low molecular weight and react to produce a polymer having a refractive index lower than that of the polymer, the low-molecular-weight compounds are diffused into the interior of the polymer, reacted, and then dried. This is a method for manufacturing a light-focusing synthetic resin body. 1.1 □ ≦ 5 〇 (suO [where vo is the volume of the polymer before immersion in the swelling liquid A,
(2) is the volume of the polymer when immersed and swollen in the liquid at 1, where the liquid content in the polymer is almost constant.]