JP2925278B2 - Gel optical supplies - Google Patents

Description

The present invention relates to an optical article. For more information, see Syndiotacticity-rich new polyvinyl alcohol (PV
A) The present invention relates to an optical article represented by a soft contact lens or an intraocular lens made of an aqueous gel of a system polymer.

[Prior Art] Regarding a gel of PVA-based polymer or its use,
Japanese Patent Application Laid-Open No. 63-23126 discloses a method in which a PVA-based polymer dissolved in a mixed solvent of water and an organic solvent is crystallized at a temperature lower than ordinary temperature to form a gel. Discloses an example in which a gel produced by this method is applied to a soft contact lens.

As a related matter, Japanese Patent Application Laid-Open No. 60-6444 discloses a soft contact lens material comprising a gel obtained by saponifying a copolymer of vinyl trifluoroacetate and a comonomer.

[Problems to be Solved by the Invention] However, the soft contact lens described in JP-A-63-23126 is based on a conventionally available PVA-based polymer. In a soft contact lens, deformation due to external stress is relatively large.

On the other hand, the soft contact lens disclosed in Japanese Patent Application Laid-Open No. 60-6444 has a modulus, that is, a relatively large initial tensile modulus. However, the initial tensile modulus (hereinafter, referred to as modulus) at a high water content is not necessarily high.

In gel optical articles, low optical distortion is extremely important and shows high oxygen permeability,
In addition, in order to reduce such distortion, a material that exhibits little deformation due to external stress at a high water content, that is, a material exhibiting a high modulus is required. Accordingly, an object of the present invention is to provide a gel optical article comprising a polymer having a high modulus even at a so-called high water content of 55% or more.

Means for Solving the Problems The present inventors have proposed that the soft contact lens disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 63-23126 has a so-called atactic (a syndiotacticity by diad display). The content was about 53 mol%), and the present inventors have conducted intensive studies and found that an optical article obtained from a PVA-based polymer having a high syndiotacticity can solve the above-mentioned problems, and have reached the present invention. .

That is, the present invention relates to the general formula [1] An optical article comprising an aqueous gel of a PVA-based polymer containing a vinyl ester unit represented by the following formula:

In the formula [1], R ¹ represents a hydrogen atom or a hydrocarbon group, R ² and R ³ represent a hydrocarbon group, but R ¹ , R ² and R ³ are the same or different and represent a hydrocarbon group. As such a hydrocarbon group, a C1-C18 hydrocarbon group such as a lower alkyl group such as methyl, ethyl, propyl and butyl; an aryl group such as phenyl; and a cycloalkyl such as cyclohexyl are preferable. R ¹ and R ² , R ² and R ³ , or R ¹ , R ² and R ³ may together form a ring. Among them, a vinyl ester represented by the following general formula [ll], which is highly syndiotactic and easily obtains a polymer having a high degree of polymerization, easily undergoes a decomposition reaction, and has good water resistance of the resulting PVA-based polymer. PVA-based polymers from polymers or copolymers are preferably used.

(Here, R ¹ , R ² and R ³ are the same as described above.) Specific examples of such a vinyl ester include vinyl pivalate, dimethyl ethyl vinyl acetate, dimethyl propyl acetate, diethyl methyl vinyl acetate, triethyl vinyl acetate, and triethyl vinyl acetate. Cyclovinyls such as trialkyl vinyl acetates such as propyl vinyl acetate and vinyl versatate, dialkyl vinyl acetates such as dimethyl vinyl acetate and diethyl vinyl acetate, methyl cyclohexyl acetate, vinyl 1-norbornane carboxylate and vinyl 3-noradamantane carboxylate And vinyl esters having the formula (1), but particularly preferred is vinyl pivalate or vinyl versatate.

In the case of a copolymer, the comonomer unit is divided into a unit that forms a vinyl alcohol unit by saponification and another unit. The former units are copolymerized for the purpose of controlling tacticity, and include vinyl acetate, vinyl formate,
Vinyl propionate, vinyl butyrate, vinyl laurate,
Vinyl esters such as vinyl stearate and vinyl benzoate, and the copolymerization amount is set in relation to the syndiotacticity amount. On the other hand, the latter comonomer is copolymerized mainly for the purpose of modification, and is in a range that does not impair the purpose of the present invention, is usually 20 mol% or less, preferably 10 mol% or less, and more preferably 5 mol% or less. used. Such units include ethylene, propylene,
Olefins such as butene and isobutene, acrylic acid and salts thereof, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-acrylate Acrylates such as -butyl, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, methacrylic acid and its salts, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, methacrylic acid Methacrylates such as n-butyl acrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, acrylamide, N-methylacrylamide, N-ethylacryl Bromide, N, N-dimethylacrylamide, diacetone acrylamide, acrylamide propanesulfonic acid and salts thereof, acrylamide propyl dimethylamine and a salt thereof or a quaternary salt, N
Acrylamide derivatives such as methylol acrylamide and its derivatives, methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propanesulfonic acid and its salts, methacrylamidopropyl dimethylamine and its salts or quaternary salts, -Methacrylamide derivatives such as methylol methacrylamide and derivatives thereof, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether, etc. Vinyl ethers, acrylonitrile, nitriles such as methacrylonitrile, vinyl chloride, vinylidene chloride, fluoride Vinyl halides such as vinylyl fluoride and vinylidene fluoride; allyl compounds such as allyl acetate allyl chloride; maleic acid and its salts or esters; itaconic acid and its salts or esters; vinylsilyl compounds such as vinyltrimethoxysilane; Examples include, but are not limited to, propenyl.

Conventionally used PVA-based polymers are so-called atactic polymers, and have a syndiotacticity of about 53 mol% as described above. On the other hand, Japanese Patent Application Laid-Open No. 60-6444 mentions that the PVA-based polymer partially has a syndiotactic structure, but the described modulus has a high water content. There is no recognition or suggestion that a PVA-based polymer having a high syndiotacticity is not necessarily high and has a small deformation due to external stress.

The optical article of the present invention is made of a PVA-based polymer having a syndiotacticity of about 55 mol% or more, and an optical article made of the polymer is a conventional PV article.
It has higher syndiotacticity, higher modulus and higher strength, and less optical distortion than optical products made from A-based polymers.

As a material of the optical article of the present invention, a PVA polymer having a syndiotacticity of about 55 mol% or more is preferable. The syndiotacticity referred to in the present invention is d ₆ −
Triad tacticity obtained from NMR spectroscopy of hydroxyl protons of completely saponified PVA dissolved in DMSO (in the case of partial saponification, measurement of completely saponified product), that is, isotacticity (l),
It means s calculated as s = S + H / 2 from heterotacticity (H) and syndiotacticity (S).

As described above, the PVA-based polymer used as a material of the optical article of the present invention preferably has a syndiotacticity of 55% by mole or more, but particularly has a syndiotacticity of 55% because of its excellent heat resistance. At least 0.01 mol% and at most 90 mol%, preferably at least 0.01 mol% and at most 70 mol%, more preferably at least 0.01 mol% and at most 50 mol%. Things are awarded. When the content of vinyl ester units in the polymer exceeds 90 mol%, the water content of optical articles such as contact lenses tends to decrease, and the strength tends to decrease. Conversely, if this unit is less than 0.01 mol%, the processability such as the solubility of the PVA-based polymer itself tends to decrease.

The degree of polymerization of the PVA-based polymer also affects the performance of the optical article obtained by the present invention. The degree of polymerization is PV
0.3dl / g of intrinsic viscosity at 30 ° C [η] of polyvinyl acetate obtained by acetylating the A-based polymer in benzene
Or more, preferably 0.65 dl / g or more, more preferably 0.98 dl / g
It is desirable that it is dl / g or more and 9.0 dl / g or less.

Next, in order to obtain the optical article of the present invention, for example, the following method can be used. That is, a solution obtained by dissolving a PVA-based polymer in a mixed solvent of an organic solvent having an affinity for water and water is poured into a mold corresponding to the shape of a target optical article, and is brought into contact with a liquid having a temperature of room temperature or lower to crystallize. PV
A gel polymer optical article of the A-based polymer may be obtained, washed with water, and the organic solvent may be completely removed to obtain a desired gel optical article of the PVA-based polymer. The optical article of the present invention can be manufactured by such a simple method. Hereinafter, a method for obtaining the optical article of the present invention will be described more specifically.

The organic solvent used for dissolving the PVA-based polymer is not particularly limited as long as it has good affinity for water and is well mixed at an arbitrary ratio, but preferred examples include dimethyl sulfoxide, glycerin, ethylene glycol, and the like. Propylene glycol, triethylene glycol,
Examples include dimethylformamide, methyl alcohol, ethyl alcohol, acetone, tetrahydrofuran, aminoethanol, phenol, n-propyl alcohol, and isopropyl alcohol. These solvents may be a mixture of two or more. In the present invention,
Among the above organic solvents, it is particularly preferable to use dimethyl sulfoxide in view of the solubility in the PVA-based polymer, the mixing ratio with water, and the decrease in freezing point.

The mixing ratio of the organic solvent and water can be arbitrarily selected. Usually, the ratio of water to the organic solvent is selected from 90:10 to 10:90 (weight ratio), but when this ratio is 70:30 to 10:90 (weight ratio), the gel strength and transparency are further increased. preferable. Although a gel can be prepared from a PVA-based polymer solution containing 100% of dimethyl sulfoxide, the gel may be slightly opaque after replacing dimethyl sulfoxide with water.

In the present invention, first, a solution of a PVA-based polymer is prepared. The concentration is preferably in the range of 2 to 30% by weight depending on the desired strength and water content. Such a solution is generally prepared by heating and dissolving the PVA-based polymer, but it may be simply heated under stirring, or may be dissolved using an autoclave or a microwave oven.

Next, the completely dissolved PVA-based polymer solution is poured into a mold having a concave surface and a convex surface corresponding to the shape of an optical article, and the mold is cooled by contacting the mold with a liquid at room temperature or lower. The temperature of the liquid is required to be a temperature at which the solvent of the PVA-based polymer solution does not freeze, but is preferably 0 ° C or lower, more preferably -10 ° C or lower, and -20 ° C or lower from the viewpoint of improving the crystallinity. Is more preferred. Further, it is preferable that the liquid is stirred rather than being left standing. The volume of this liquid is preferably at least 10 times the volume of the mold. The time for contact with the liquid is preferably 3 minutes or more, more preferably 1 hour or more, for stabilizing crystallization.

The liquid is not particularly limited as long as it maintains a liquid state in a desired temperature range. For example, water, alcohols such as methanol and ethanol, acetone, chloroform,
Examples thereof include an aqueous solution in which halogenated hydrocarbons such as trichlene, hydrocarbons such as hexane and benzene, dimethyl sulfoxide, or salts such as sodium chloride, calcium chloride, and sodium sulfate are dissolved. These liquids and aqueous solutions may be mixtures. Among them, a mixed solution of ethanol, acetone, trichlene, hexane, and water-dimethyl sulfoxide is preferable in view of handleability.

In this way, the liquid cooled to a temperature below room temperature
When the mold charged with the solution of the A-based polymer is brought into contact and cooled, the surface of the manufactured lens is smooth, and the image of the lens is clear and has a high modulus. In addition, the mold charged with the PVA-based polymer solution can be freely cooled via gas.

The shape and the material of the mold are generally round and consist of two portions of irregularities, but are not particularly limited. Although the mold is usually used repeatedly, it may be disposable.

In the present invention, further, a cross-linking reaction is carried out using glutaraldehyde or boric acid in order to sterilize and improve the dimensional stability, heat resistance, mechanical strength, and the like of the obtained PVA polymer gel optical article. Or irradiation with radiation such as γ-rays or electron beams.

[Examples] Next, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

 In the examples, all “parts” represent parts by weight.

Reference Example 1 (Preparation of PVA-based polymer) Vinyl pivalate monomer was placed in a reactor equipped with a stirrer.
600 parts and 200 parts of methanol were charged, and the system was replaced with nitrogen by bubbling nitrogen gas. Separately, a solution prepared by dissolving 0.0712 parts of 2,2'-azobisisobutyronitrile as an initiator in methanol was prepared, and nitrogen was replaced by bubbling with nitrogen gas.

When the temperature of the reaction vessel was raised and the internal temperature reached 60 ° C., a methanol solution in which an initiator was dissolved was injected to initiate polymerization. After 150 minutes, when the polymerization rate reached 42%, the polymerization was stopped by cooling, and while the t-butanol was occasionally converted, unreacted vinyl pivalate monomer was removed under reduced pressure.
A t-butanol solution of polyvinyl pivalate was used. Subsequently, t-butanol was distilled off under reduced pressure to obtain 45.7% by weight of a polyvinyl polypivalate solution in tetrahydrofuran.

The solution is then placed in a reactor equipped with a stirrer and reflux condenser.
21.9 parts were charged, heated to 60 ° C., flushed with nitrogen gas and replaced with nitrogen, and kept at 60 ° C., separately prepared and replaced with nitrogen.
21 parts by weight of a methanol solution of potassium hydroxide by weight was added and stirred thoroughly. This solution gelled in about 20 minutes, but was further kept at 60 ° C. for 100 minutes, and then 3.8 parts of acetic acid was added together with 20 parts of methanol to neutralize potassium hydroxide. Subsequently, after the gel was pulverized, Soxhlet washing with methanol was performed to obtain PVA. To 0.5 part of the obtained PVA, 10 parts of acetic anhydride and 2 parts of pyridine were added, and the tube was sealed.
The mixture was heated at 120 ° C. for 8 hours to acetylate. The obtained polyvinyl acetate was precipitated with n-hexane, and re-precipitated twice with an acetone / n-hexane system to purify. The obtained PVA is d
This PVA was dissolved in _6- DMSO and measured by ¹ H-NMR.
Contained 99.6 mol% of vinyl alcohol units and 0.4 mol% of vinyl pivalate units, and had syndiotacticity of 61.7 mol%. [Η] measured at 30 ° C. in benzene of polyvinyl acetate obtained by acetylation was 1.
It was 17 dl / g.

Reference Example 2 (Preparation of PVA-based polymer) Vinyl pivalate monomer was placed in a reactor equipped with a stirrer.
870 parts and 130 parts of methanol were charged, and the system was purged with nitrogen by bubbling nitrogen gas. Separately, a solution was prepared by dissolving 0.080 part of 2,2'-azobisisobutyronitrile in methanol as an initiator, and the atmosphere was replaced with nitrogen by bubbling with nitrogen gas.

When the temperature of the reaction vessel was raised and the internal temperature reached 60 ° C., a methanol solution in which an initiator was dissolved was injected to initiate polymerization. After 220 minutes, when the polymerization rate reached 30%, the polymerization was stopped by cooling, and the unreacted vinyl pivalate monomer was distilled off under reduced pressure, and methyl ethyl ketone was added thereto to add 20% by weight of polyvinyl pivalate. Was prepared as a methyl ethyl ketone solution.

Next, the solution was placed in a reactor equipped with a stirrer and a reflux condenser.
Charge 150 parts, 90 parts of methyl ethyl ketone and 60 parts of methanol, heat to 60 ° C., purge with nitrogen by flowing nitrogen gas, and maintain at 60 ° C., then separately prepare and replace with 25% of nitrogen
63.6 parts of a methanol solution of potassium hydroxide was added, and the mixture was sufficiently stirred. The system gelled in about 13 minutes,
, And potassium hydroxide was neutralized by adding 25 parts of acetic acid together with 10 parts of methanol. Subsequently, after the gel was pulverized, Soxhlet washing with methanol was performed to obtain PVA. To 0.5 parts of the obtained PVA, 10 parts of acetic anhydride,
After adding 2 parts of pyridine and sealing the tube, it was heated at 120 ° C. for 8 hours to acetylate. The obtained polyvinyl acetate was precipitated in n-hexane, and reprecipitated twice in an acetone / n-hexane system, and purified. The resulting PVA was dissolved in d ₆ -DMSO, ¹ H
When the NMR spectrum was measured, the PVA contained 80.6 mol% of vinyl alcohol units and 19.4 mol of vinyl pivalate units.
Mol%, and syndiotacticity was 61.5%. [Η] of the polyvinyl acetate obtained by acetylation measured at 30 ° C. in benzene was 1.75 dl / g.

Example 1 10 g of the PVA obtained in Reference Example 1 was added to 90 g of an 80% by weight aqueous solution of dimethyl sulfoxide, and the mixture was stirred with a magnetic stirrer at 140 ° C. for 2 hours to be dissolved to obtain a uniform solution.

This PVA solution was heated to 90 ° C., and the contact lens and the convex mold having a diameter of 16 mm were heated to the same temperature. Inject 2 ml of the above solution into the concave mold, immediately press it with a convex mold, and at -20 ° C.
In an ethyl alcohol bath for 20 hours. Thereafter, the mold was taken out of the ethyl alcohol bath, left to reach room temperature, and the formed soft contact lens was taken out and immersed in distilled water. After 30 minutes, the distilled water was renewed. In this manner, the replacement with water was carried out until no more dimethylsulfoxide could be detected by gas chromatography.

The PVA soft contact lens swollen with water was observed with a transmission stereo microscope and a transmission projector (10 magnification). The lens surface was uniform and no defects such as striae were observed.

 The sharpness of the image formed by the lens was also good.

The results of a tensile test of this lens are shown in Table 1. The lens showed a very high modulus, that is, an initial tensile modulus.

Example 2 A contact lens was obtained in the same manner as in Example 1 except that 15 g of the PVA-based polymer was dissolved in 85 g of an 80% by weight aqueous solution of dimethyl sulfoxide. Table 1 shows the tensile test results of the present lens. This lens also showed a very large modulus.

Comparative Examples 1 and 2 The same operation as in Examples 1 and 2 was carried out using PVA (Kuraray Co., Ltd., PVA-117H) having a degree of polymerization of 1750, a degree of saponification of 99.6 mol%, and a syndiotacticity of 53.5 mol%. Contact lenses were obtained. Table 1 shows the tensile test results of the present lens.

Example 3 A contact lens was obtained in the same manner as in Example 2 using the PVA obtained in Reference Example 2. Table 1 shows the tensile test results of the present lens. This lens also showed a very large modulus.

[Effects of the Invention] According to the present invention, optical articles such as soft contact lenses, intraocular lenses, and corneal inlays having a high water content and a large initial tensile modulus (modulus) can be obtained. Such an optical article is a practical optical article with little optical distortion because of little deformation due to external stress at a high moisture content, and the usefulness of the present invention is great.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02C 7/04

Claims (1)

(57) [Claims] 1. The general formula [1] (In the formula, R ¹ represents a hydrogen atom or a hydrocarbon group, and R ² and R ³ represent a hydrocarbon group.) An optical article comprising an aqueous gel of a polyvinyl alcohol-based polymer containing a vinyl ester unit represented by the following formula: