JPH0476367B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a (meth)acrylate-fluorinated (meth)acrylate copolymer.
Specifically, the present invention provides an ultra-high molecular weight (meth)acrylate-fluorinated (meth)acrylate having an arbitrary refractive index between the refractive indexes of the homopolymers of each monomer and having excellent heat resistance, mechanical strength, etc. It relates to acrylate copolymers. (Prior Art) In recent years, the use of optical technology in place of electrical and electronic technology has been attracting attention in the fields of measurement, information transmission and processing, and the like. In such optical technology, quartz glass-based, multi-component glass-based, and plastic-based materials are currently used as optical materials constituting, for example, transmission paths. Among these, plastic-based materials are inferior to quartz glass-based materials in terms of characteristics such as transmission loss, but they are superior in economy, processability, and workability, and are lightweight and have excellent performance such as impact resistance and vibration resistance. It is in good condition. For example, when an optical fiber is used, it has the advantage of being able to use visible light with a large diameter, having a large numerical aperture, and being easy to bend. However, plastic materials have inferior heat resistance compared to inorganic materials such as quartz glass and multi-component glass, and their optical properties are highly dependent on temperature, so the scope of use of plastic materials as optical materials is limited. , it had become quite limited. For example, polymethyl methacrylate has excellent transparency and low birefringence, and has been widely used as an optical material. When produced, it can only be used at temperatures below the heat resistance temperature of polymethyl methacrylate or other plastic materials, and its limit is usually around 100°C. Furthermore, when combined with inorganic materials such as silica glass and multi-component glass, the rate of change of the refractive index of the two with respect to temperature is significantly different (about a difference of 10 ² orders of magnitude), so the refractive index difference between the two varies greatly depending on the temperature. However, it was practically unusable in an environment with temperature changes. By the way, the present inventors have discovered that a plasma-initiated polymerization method in which a gas phase containing monomer vapor is first irradiated with plasma, and the generated polymerization-initiating active species are guided to the solidified phase of the monomer to perform chain growth polymerization of the monomer, at least We developed a plasma-initiated polymerization method that uses a radical polymerization initiator in combination with a radical polymerization initiator that is present in the gas phase (Japanese Patent Application Laid-Open No.
60−22001). According to this method, it is possible to easily obtain an ultrahigh molecular weight polymer in high yield,
For example, in the case of polymethyl methacrylate, ultra-high molecular weight polymethyl methacrylate with a molecular weight on the order of 10 ⁷ can be obtained. Such ultra-high molecular weight polymethyl methacrylate has the same excellent transparency and properties as conventional polymethyl methacrylate.
It not only has low birefringence, but also has excellent high-temperature mechanical properties, as well as excellent abrasion resistance and attraction strength, and can be suitably used as an optical material. Therefore, a material that has an appropriate refractive index difference with respect to such ultra-high molecular weight poly(meth)acrylate and has almost the same properties as the ultra-high molecular weight poly(meth)acrylate in other properties is needed. If developed, the scope of use of plastic materials as optical materials will be greatly expanded. (Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a novel plastic optical material. Another object of the present invention is to provide a plastic optical material that has an appropriate refractive index difference with respect to ultra-high molecular weight poly(meth)acrylate and has excellent heat resistance, mechanical strength, etc. The present invention further provides a plastic (meth)acrylic copolymer having an arbitrary refractive index difference between homopolymers of each monomer and obtained by a plasma initiated polymerization method using a radical polymerization initiator. The purpose is to provide a system optical material. (Means for Solving the Problems) The above objects are such that the main chain is substantially composed of the following repeating units (A) and (B) arranged in a molar ratio of 4:1 to 200:1, Intrinsic viscosity η in benzene at 30℃ is 1
Characterized by ×10 ³ to 4 × 10 ³ (meta)
This is achieved using an acrylate-fluorinated (meth)acrylate copolymer.

【formula】

[Formula] (In the formula, R ¹ and R ³ are hydrogen or methyl groups, R ²
is an alkyl group having 1 to 5 carbon atoms, and R ⁴ is a fluorinated alkyl group having 1 to 5 carbon atoms and having 1 to 11 fluorine substituents. ) The present invention also provides (meth)acrylate having a heat distortion temperature of 150°C or higher and a total light transmittance of 90% or higher.
It shows a fluorinated (meth)acrylate copolymer. (Function) Therefore, in the present invention, the intrinsic viscosity η is 1 × 10 ³ ~
Since it is a (meth)acrylate-fluorinated (meth)acrylate copolymer characterized by a molecular weight of 4×10 ³ , it has a lower molecular weight than a general (meth)acrylate-fluorinated (meth)acrylate copolymer.
It is an ultra-high molecular weight polymer that is about 10 to 100 times larger, has excellent high-temperature mechanical properties, and also has good mechanical strength. In addition, the refractive index of the ultra-high molecular weight polymer varies depending on the fluorine content compared to the refractive index of the (meth)acrylate homopolymer, that is, the refractive index of the (meth)acrylate and fluorinated (meth)acrylate copolymer. Therefore, it can have any suitable refractive index difference with respect to the (meth)acrylate homopolymer. Furthermore, the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention can be easily obtained in good yield by a plasma-initiated polymerization method using a radical polymerization initiator. As mentioned above, the polymer obtained by the plasma initiated polymerization method using a radical polymerization initiator can be an ultra-high molecular weight polymer. For example, when methyl methacrylate is used as a monomer, the intrinsic viscosity η is 10. Polymethyl methacrylates on the order of ³ can be prepared. Therefore, a refractive index that has excellent optical properties similar to such ultra-high molecular weight poly(meth)acrylate and has an appropriate refractive index difference with respect to the refractive index of the ultra-high molecular weight poly(meth)acrylate is needed. If polymers having the above-mentioned properties can be obtained by the plasma-initiated polymerization method described above, their use as optical materials is promising. However, monomers that can be polymerized by plasma-initiated polymerization are generally (meth)
It is believed that the polymers are acrylate, (meth)acrylic acid, (meth)acrylamide, etc., and it has been difficult to obtain a polymer that meets the above requirements. As a result of extensive research, the present inventors found that
We have discovered that the polymerization of a (meth)acrylate-fluorinated (meth)acrylate copolymer can easily proceed and become ultra-high molecular weight polymerization by a plasma-initiated polymerization method that uses a radical polymerization initiator in combination, leading to the present invention. be. Hereinafter, the present invention will be explained in more detail based on embodiments. The (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention has an intrinsic viscosity η of 1×
10 ³ to 4×10 3 , and the main chain is substantially a repeating unit.

【formula】

[Formula] (wherein R ¹ and R ³ are hydrogen or methyl groups, R ² is an alkyl group with 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, R ⁴ is 1 to 11 carbon atoms, More preferably, it is a fluorinated alkyl group having 1 to 7 carbon atoms and 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms. The intrinsic viscosity η=3.6×10 ³ corresponds to 5×10 ⁷ when converted to the viscosity average molecular weight of polymethacrylate. As described above, the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention has an extremely high intrinsic viscosity, or in other words, an ultra-high molecular weight, so it has excellent heat resistance, mechanical strength, etc. , the temperature dependence of optical properties can be kept low. Furthermore, since the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention is a (meth)acrylate copolymer, it has good optical properties such as transparency and total light transmittance. Since it is suitable as a material and has almost the same physical properties as the similar ultra-high molecular weight poly(meth)acrylate except for the refractive index, it can be combined and applied to various optical fields. The refractive index of the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention is a value between the refractive index of the homopolymer of each monomer, that is, the refractive index of poly(meth)acrylate and polyfluorinated (meth)acrylate. The composition ratio can be arbitrarily varied within the range of the composition ratio shown below. For example, in the case of methyl methacrylate-trifluoroethyl methacrylate copolymer, the refractive index of polymethyl methacrylate n ²⁵ _D = 1.49
and the refractive index of polytrifluoroethyl methacrylate n ²⁵ _D = 1.42, but
In particular, it is desired that the refractive index difference with respect to poly(meth)acrylate be about 10 ^-3 to 3×10 ^-1 . Furthermore, it is particularly desirable for the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention to have a heat distortion temperature of 150°C or higher and a total light transmittance of 90% or higher when used as an optical material. be. The (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention is produced by allowing a radical polymerization initiator to exist in a gas phase containing monomer vapor, and irradiating plasma into this gas phase to generate a polymerization reaction. It can be prepared easily and with good yield by a plasma-initiated polymerization method that uses a radical polymerization initiator in combination with a radical polymerization initiator that introduces the activated species into the monomer solidification phase to perform chain growth polymerization of the monomers. In addition, in this polymerization method, it is not necessary that all types of monomers constituting the copolymer be present in the gas phase, and all types of monomers may even be present in the post-polymerization process after plasma irradiation. Only one type of monomer may be present in the gas phase. In addition, when alcohol is present in the coagulation phase for post-polymerization, the polymerization time is shortened and the yield is also improved (JP-A-60-224892). The (meth)acrylate that is one of the monomers constituting the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention includes methyl methacrylate, ethyl methacrylate, n-
Examples include (meth)acrylates having an alkyl group having 1 to 5 carbon atoms, such as butyl methacrylate, methyl acrylate, ethyl acrylate, and n-butyl acrylate, and the other monomer, fluorinated (meth)acrylate, includes monofluoromethyl Methacrylate, difluoroethyl methacrylate, trifluoroethyl methacrylate, trifluoroisopyl methacrylate, hexafluoroisopyl methacrylate, monofluoromethyl acrylate, difluoroethyl acrylate, trifluoroethyl acrylate, trifluoroisopylacrylate, hexafluoroisopylacrylate, etc. Examples include fluorinated (meth)acrylates having a fluorinated alkyl group having 1 to 5 carbon atoms, and the number of fluorine substitutions in the fluorinated alkyl group is preferably about 1 to 7. The composition ratio of these monomers is (meth)acrylate:fluorinated (meth)acrylate in a molar ratio of 4:1 to 200:1, more preferably 8:1 to 20:
1. Particularly preferably, it is within the range of 10:1 to 15:1 from the viewpoint of polymerization yield and physical properties of the obtained copolymer, but if it is within this range, the desired copolymer It can be arbitrarily changed depending on the refractive index to be imparted to. Furthermore, in the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention, the (meth)acrylate component and the fluorinated (meth)acrylate component do not necessarily have to be one type of each, but a plurality of them. It is also possible to make a multi-component polymer by combining these. Among these monomer combinations, particularly preferred are methyl methacrylate and trifluoroethyl methacrylate. On the other hand, the radical polymerization initiator used in the plasma-initiated polymerization method may be any one used in general radical polymerization of monomers, such as acetylcyclohexylsulfonyl peroxide, isobutyryl peroxide, Cumyl peroxyneodecanoate, diisopropyl peroxydicarbonate, di-n
-Propyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, dimyristyl peroxydicarbonate, di-(2-ethoxyethyl)peroxydicarbonate, di-(methoxyisopropyl)peroxy)dicarbonate, di-(2-ethylhexyl) Peroxides such as peroxy) dicarbonate, di-(3-methyl-3-methoxybutyl) peroxydicarbonate, t-butyl peroxyneodecanoate, potassium persulfate, ammonium persulfate, 2,2'- Low-temperature active radical polymerization initiators such as azo compounds such as azobis(4-methoxy-2,4-dimethylvaleronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile), and t-butylcumyl peroxide. , diisopropylbenzene hydroperoxide, di-t-butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane-3,1,1,3 , 3-tetramethylbutyl hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,1-bis(t-butylperoxy) −
3,3,5-trimethylcyclohexane, 1,1
-bis(t-butylperoxy)cyclohexane, t-butylperoxymaleate, t-butylperoxylaurate, t-butylperoxy-3,5,5-trimethylhexanoate, t-
butyl peroxy-2-ethylhexanoate,
Cyclohexanone peroxide, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,2-bis(t-butylperoxy)
Octane, t-butyl peroxyacetate,
2,2-bis(t-butylperoxy)butane,
t-Butyl peroxybenzoate, n-butyl-4,4-bis(t-butylperoxy)valerate, di-t-butyl diperoxyisophthalate, methyl ethyl ketone peroxide, α,α'-
Bis(t-butylperoxyisopropyl)benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butyl hydroperoxide, m-toluoyl peroxide, benzoyl peroxide,
Peroxides such as t-butyl peroxyisobutyrate, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide, succinic acid peroxide, 1,1'-azobis(cyclohexane) There are high temperature active radical polymerization initiators such as azo compounds such as 1-carbonitrile) and azobisisobutyronitrile. Here, the low-temperature active radical polymerization initiator is one with a decomposition temperature of 50°C or less to obtain a 10-hour half-life,
On the other hand, as a high-temperature active radical polymerization initiator, the decomposition temperature to obtain a 10-hour half-life is about 60 to 220°C. The amount of these radical polymerization initiators to be added to the monomer cannot be determined unconditionally because it depends on the degree of polymerization of the polymer to be obtained and the types of monomer and radical polymerization initiator. However, it is not preferable to add more radical polymerization initiator than necessary because the radical polymerization initiator will not disappear during the polymerization period and will remain in the resulting polymer. For example, when trying to obtain a methyl methacrylate-trifluoroethyl methacrylate copolymer with an intrinsic viscosity η on the order of 10 ³ , benzoyl peroxide ( ^BPO ) has ^a 6× for bisisobutyronitrile (AIBN)
It is about 10 ^-5 to 6×10 ^-3 mol/. The plasma used in the above plasma-initiated polymerization method is preferably non-equilibrium plasma, especially low-temperature plasma generated by glow discharge. Obtained by applying a voltage of 30-50W. The electrodes used include external or internal parallel plate electrodes or coiled electrodes, preferably external parallel plate electrodes. The plasma generation source gas may be any gas such as hydrogen, methane, nitrogen, argon, ethylene, etc.
Alternatively, it may be the monomer gas itself. In addition, in the plasma initiated polymerization method, generally, during plasma irradiation, the solidified phase 2 of the monomer and the gas phase 1 of the monomer are not separated by a partition wall or the like, but in a container 3, as shown in FIGS. 1a and 1b. An equilibrium state is maintained, and post-polymerization is initiated when polymerization active species generated by plasma irradiation of the gas phase 1 come into contact with the surface of the solidified phase. However, as is known, for example, in a plasma initiated polymerization method, as shown in FIGS.
For example, the gas phase 1 is separated by a partition wall 3, etc.
It is also possible to remove the partition wall 3 after performing plasma irradiation, guide the gas phase 1 containing the polymerization active species to the coagulation phase 2, and bring the polymerization active species into contact with the coagulation phase 2 to initiate post-polymerization. As shown in Figures 3a to 3d, during plasma irradiation, only the gas phase 1 containing monomer vapor is sealed in the plasma reactor 4, and after the plasma irradiation, the gas phase 1 is discharged from the reactor 4 to the outside of the system. It is also possible to carry out post-polymerization in the coagulation phase 2 by reintroducing new monomer into the reactor 4 that has been removed and then subjected to plasma irradiation. This method is possible because an ultra-thin film of polymer is coated on the surface of the plasma reactor 4 made of a material such as glass even during plasma-initiated polymerization, and the polymerization active species are absorbed by this polymer. This is because the matrix structure traps the polymer, and also because there is a finely powdered plasma-polymerized polymer in which similar polymerization active species are trapped in the gas phase 1 (Masayuki Kuzuya, "Plasma-initiated polymerization mechanism") , Proceedings of the Plasma Chemistry Symposium (November 14, 1984)). In addition, when carrying out the plasma-initiated polymerization method by the method shown in FIGS. 1a-b or 3a-c, the material of the plasma reactor 4 used is particularly one made of an ultra-thin polymer film for the upper gas electrode. It is desirable to use a material that can be easily coated, such as various glasses such as quartz glass and pyrex glass, and preferably pyrex glass. In FIGS. 1a, 2a, and 3a, reference numeral 5 indicates an electrode, 6 indicates an RF oscillation device, and 7 indicates a control unit. Therefore, the plasma irradiation to the gas phase 1 is carried out at a temperature at which monomer vapor can exist in the reduced pressure gas phase 2;
Generally, irradiation is carried out under temperature conditions near room temperature, and the irradiation time is not particularly limited, but a short time is sufficient to generate polymerization active species.
Usually it takes several seconds to several minutes. Further, the postpolymerization in the coagulation phase 2 is carried out at room temperature, although it depends on the type of radical polymerization initiator used. In other words, if the post-polymerization is carried out at too high a temperature, the reaction will proceed thermally.
This is because there is a risk of producing a polymer with a low degree of polymerization. In addition, if the polymerization is carried out at too low a temperature, there is a possibility that the polymerization will not proceed properly. However, when a low-temperature active radical polymerization initiator is used as a radical polymerization initiator, post-polymerization in the coagulation phase is carried out in a low-temperature range, such as 0 to It progressed satisfactorily even at -20°C. Further, the degree of polymerization of the polymer obtained in the plasma-initiated polymerization method of the present invention can be adjusted by generating a stoichiometric amount of the polymerizable active species when the polymerizable active species is obtained by plasma irradiation. In addition, examples of the alcohol used when adding it to the reaction system as described above include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol,
1 carbon atom such as tert-butanol, n-amyl alcohol, isoamyl alcohol, hexanol, peptanol, octanol, caprylic alcohol, nonyl alcohol, decyl alcohol, etc.
About 10 alcohols can be mentioned, among which lower alcohols, particularly methanol, are preferable.
Note that these alcohols may be used during plasma irradiation.
It may or may not be present in the gas phase. The (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention obtained in this manner can be used for various purposes as an optical material, and can be obtained by a similar plasma-initiated polymerization method. In combination with ultra-high molecular weight poly(meth)acrylate, it can be used for example in optical fibers, optical waveguides used in splitters, polarizers, etc., or in addition, in JP-A-59-
It can be suitably used as a material constituting the light guide system of a contact type color image sensor as shown in No. 113660. When combined with ultra-high molecular weight poly(meth)acrylate in this way, the ultra-high molecular weight poly(meth)acrylate and ultra-high molecular weight (meth)acrylate-fluorinated (meth)acrylate copolymer constituting each member will eventually It also has high heat resistance, vibration resistance, and impact resistance, so it exhibits sufficient performance even in harsh environments. It is possible to almost match the refractive index change and expansion coefficient, etc. with respect to the temperature change, eliminating the risk of optical distortion such as birefringence due to fluctuations in the refractive index difference due to temperature changes and stress caused by temperature changes, and high thermal deformation. The optical properties are stable up to temperatures close to that of the original. (Examples) Hereinafter, the present invention will be described in more detail based on Examples. Example 1 Polymer tube made of Pyrex glass with an inner diameter of 15 mm (capacity
1.71 ml of trifluoroethyl methacrylate (TFEMA), 12.82 ml of methyl methacrylate (MMA), and 4.13×10 ^-3 mol of benzoyl peroxide (BPO) were added to a 42 ml tube, and the polymerization tube was connected to a vacuum line and frozen with liquid nitrogen. . This system
It was degassed at 10 ^-3 Torr or less to sufficiently remove oxygen from the system and melt again. After repeating this operation three times, the pot was closed and the monomer in the polymerization tube was again sufficiently cooled and frozen using liquid nitrogen. Plasma was generated in the gas phase when a portion of the monomer in the polymerization tube began to dissolve at around room temperature. The electrodes used were parallel plate electrodes made of copper, 15.0 x 10.0 cm, with a distance between the electrodes of 18 mm, and an output of 50 W was applied to the electrodes by a radio frequency (RF) transmitter with a 13.56 MHz control unit. Plasma irradiation time is
It was hot in 60 seconds. After plasma irradiation, the polymerization tube was sealed and polymerized by shaking at 25℃ for 5 days (post-polymerization).
I did this. The resulting polymerization reaction product was purified by dissolving it in benzene, reprecipitating it with methanol, filtering it, and drying it under vacuum at 80°C to obtain a white polymer. The yield was 19.7% by weight. When the obtained polymer was subjected to infrared absorption spectrum,
υ _CE3 660cm ^-1 , an absorption of 1040cm ^-1 thought to be based on the aryl fluoride system was observed, and υ _C=0 1740cm ^-1 , δ _CH 1240 which is a polymethyl methacrylate skeleton.
cm ^-1 , υ _C-0 1300 to 1160 cm ^-1 is observed.
It was confirmed that it was a TFEMA-MMA copolymer. An infrared absorption spectrum chart is shown in FIG. Various physical properties of this TFEMA-MMA copolymer were measured by the methods described below. The results are shown in Table 1. Reference Example 1 Polymerization was carried out in the same manner as in Example 1, except that 5.0 ml of TFEMA and 4.13×10 ^-3 mol/BPO were added to the polymerization tube, to obtain a white polymer with a slight rubber elasticity. The yield was 1.5% by weight. When this polymer was subjected to an infrared absorption spectrum, a chart as shown in FIG. 5 was obtained, and it was confirmed that it was polytrifluoroethyl methacrylate. Various physical properties of this polymer were measured by the methods described below. The results are shown in Table 1. Reference Example 2 Polymerization was carried out in the same manner as in Example 1 except that 15.0 ml of MMA and 4.13×10 ^-3 mol/BPO were added to the polymerization tube, and a colorless polymer was obtained with a yield of 77.0% by weight.
When this polymer was subjected to an infrared absorption spectrum, a chart as shown in FIG. 6 was obtained, and it was confirmed that it was polymethyl methacrylate.
Various physical properties of this polymer were measured by the methods described below. The results are shown in Table 1. Reference Example 3 Polymerization was carried out in the same manner as Reference Example 1 except that BPO was not added. Since the yield was 0, it was assumed that no polymerization reaction occurred. Intrinsic Viscosity To measure the intrinsic viscosity η, the polymer was dissolved in benzene and the intrinsic viscosity η was measured at 30°C.
Mark-Howink equation η
-KM〓, the average molecular weight M of PMMA was calculated. However, in PMMA, K=5.2×10 ^-3 , α=
It was set to 0.76. Refractive index Dissolve 0.1g of polymer in 10ml of chloroform,
A film with a thickness of 20 μm was produced by casting. The refractive index for the D-line (589 nm) of the film from which the solvent had been completely removed was determined using an Atsube refractometer (manufactured by Atago Co., Ltd., model No. 302). The measurement was performed at 25°C using 5 mol/potassium mercury iodide aqueous solution as an intermediate solution. Melting temperature The polymer powder was measured using a micro melting point measuring device (manufactured by Yanagimoto Seisakusho Co., Ltd.). Total light transmittance was measured using ASTM D1003 test method.

[Table] Copolymer
(1:10)

[Table] (Effect of the invention) As described above, the present invention has a main chain in which the following repeating units (A) and (B) are substantially arranged in a molar ratio of 4:1 to 200:1. It is a (meth)acrylate-fluorinated (meth)acrylate copolymer characterized by an intrinsic viscosity η of 1×10 ³ to 4×10 ³ in benzene at 30°C, and has an ultra-high molecular weight structure. Because of this, it has excellent heat resistance, mechanical strength, etc., and has low temperature dependence of optical properties such as refractive index, so it can be suitably used as various optical materials.
For example, by combining similar ultra-high molecular weight poly(meth)acrylates with appropriate refractive index differences, optical fibers,
It can be applied to applications such as optical waveguides and light guide systems for contact type color image sensors. Further, when the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention has a heat distortion temperature of 150°C or higher and a total light transmittance of 90% or higher, it can provide even better characteristics to the optical system. Become something.

[Brief explanation of the drawing]

Figures 1a-b, 2a-b and 3a-d
The figures each show an embodiment of the plasma-initiated polymerization method used to prepare the (meth)acrylate-fluorinated (meth)acrylate copolymer of the present invention.
An infrared absorption spectrum chart of an example of a fluorinated (meth)acrylate copolymer, FIG. 5 is an infrared absorption spectrum chart of polytrifluoroethyl methacrylate, and FIG. 6 is an infrared absorption spectrum chart of polymethyl methacrylate. This is a spectrum chart. 1... Monomer gas phase, 2... Monomer solidification phase,
3...Plasma reactor.

Claims (1)

[Scope of Claims] 1. The main chain is substantially composed of the following repeating units (A) and (B) arranged in a molar ratio of 4:1 to 200:1, and 30
The intrinsic viscosity η in benzene at °C is 1×10 ³ to 4×
10 ³ A (meth)acrylate-fluorinated (meth)acrylate copolymer. [Formula] [Formula] (In the formula, R ¹ and R ³ are hydrogen or methyl groups, R ²
is an alkyl group having 1 to 5 carbon atoms, and R ⁴ is a fluorinated alkyl group having 1 to 5 carbon atoms and having 1 to 11 fluorine substituents. )