JPH11153776A - Lens for eye and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce a lens, to improve shape stability and mechanical strength and to maintain an excellent high water-holding rate by hydrolyzing a copolymer which consists of vinyl esters and N-vinylpyrrolidone and triallyl(iso)cyanurate or the like as the crosslinking component. SOLUTION: The crosslinked polyvinylalcohol lens for eyes containing N- vinylpyrrolidone as the structural component is obtd. by hydrolyzing a copolymer comprising vinylesters expressed by the formula and N-vinylpyrrolidone and triallyl(iso)cyanurate or diallylidene pentaerythrite as the crosslinking component. In the formula, R is a hydrocarbon group. In this case, the hydrocarbon group expressed by R is preferably 1 to 8C alkyl group, cycloalkyl group or aryl group. As vinylesters, for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl acrylate, vinyl methacrylate and vinyl sorbate can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmic lens and a method for manufacturing the same. More specifically, the present invention relates to a novel crosslinked polyvinyl alcohol intraocular lens and contact lens and a method for producing the same.

[0002]

2. Description of the Related Art Polyvinyl alcohol is excellent in biocompatibility and is a hydrogel having a high water content, and is expected to be used as ophthalmic lenses such as contact lenses and intraocular lenses.

[0003] In general, polyvinyl alcohol is obtained by hydrolyzing a polyvinyl ester such as polyvinyl acetate, but it is not easy to crosslink the polyvinyl alcohol. That is, in the conventional crosslinking of polyvinyl alcohol, a method has been employed in which polyvinyl acetate is first hydrolyzed into polyvinyl alcohol, and then crosslinked with aldehyde or the like. However, in this method, it is not easy to control the degree of cross-linking of polyvinyl alcohol, and thus it is difficult to maintain a high water content and to maintain a balance between shape stability and mechanical strength.

Also, polyvinyl alcohol itself is difficult to form into a lens shape due to its unique properties, and the polyvinyl alcohol itself is easily dried in the air. It was easy to use and had a dry feeling when worn on the eyes, and the use of polyvinyl alcohol materials for ophthalmic lenses was not satisfactory.

On the other hand, JP-A-9-40719 discloses a copolymer comprising vinyl acetate and triallyl isocyanurate, and JP-A-9-40720 discloses a copolymer comprising vinyl acetate and dialylidenepentaerythritol. A crosslinked polyvinyl alcohol ophthalmic lens is disclosed which hydrolyzes the copolymer after cooling into a lens shape under cooling.

[0006] Japanese Patent Application Laid-Open No. 9-43547 discloses that
As an improvement of Japanese Patent Application Laid-Open No. 9-40720, a crosslinked polyvinyl alcohol ophthalmic lens characterized by preliminarily polymerizing a mixture of vinyl acetate and a crosslinking agent is disclosed.

Further, in order to achieve both strength and high water content, JP-A-59-2299 discloses a polyvinyl alcohol-based polymer and a block polymer of a hydrophobic monomer.
Mixtures with N-vinylpyrrolidone polymers are disclosed.

[0008]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. 9-40719
In Japanese Patent Application Laid-Open No. 9-40720 and in Japanese Patent Application Laid-Open No. 9-40720, after bulk polymerization of triallyl isocyanurate and diarylidenepentaerythritol as a cross-linking agent and vinyl acetate in a container such as a test tube, the polymer is cooled. It is hydrolyzed from lens-like material by machining such as cutting and polishing,
The obtained lenticular material is useful as a crosslinked polyvinyl alcohol ophthalmic lens having a high water content.

However, since it is a thermal polymerization method in a test tube, it is difficult to handle vinyl acetate having a small specific gravity and easy to vaporize, and it is difficult to carry out polymerization with triallyl isocyanurate and dialylidene pentaerythrit which have a large specific gravity and are difficult to vaporize. Control was not easy. That is, when several lens-like objects are cut out from one rod-like lump, the swelled lens has variations in lens shape and shape stability, and a lens of uniform quality can be obtained. There was a problem of difficulty.

Further, the vinyl acetate copolymer cannot be sufficiently hardened at room temperature, so it must be machined while cooling, and the manufacturing process is complicated such as maintaining the processing conditions. It was difficult to mass-produce continuously at low cost. In addition, although the machining is performed while cooling, the processing heat generated during the processing adversely affects the vinyl acetate copolymer, and as a result, the lens surface after the processing becomes rough and is optically satisfactory. It was not something.

Further, Japanese Patent Application Laid-Open No. 9-43547, which is an improved patent of Japanese Patent Application Laid-Open No. 9-40720, discloses a method for overcoming the disadvantages of vinyl acetate such as low boiling point, low viscosity and large polymerization shrinkage. After pre-polymerization, thermal polymerization was performed in a glass mold for contact lens molding.However, since low-temperature vinyl acetate was used for thermal polymerization to raise the temperature to 80 ° C., unpolymerized resin in the mold was not used. The vinyl acetate vaporized, and the resulting lens had non-uniform physical properties such as water content, shape stability, and mechanical strength.

In Japanese Patent Application Laid-Open No. Sho 59-2299,
It is said that the N-vinylpyrrolidone polymer is confined within the three-dimensional crosslink of the polyvinyl alcohol polymer in order to crosslink the polyvinyl alcohol polymer later by acid treatment or the like. In addition, it is difficult to control the crosslinking, it is difficult to grasp whether the N-vinylpyrrolidone polymer is incorporated at a desired ratio, and it is not possible to maintain the high water content of polyvinyl alcohol itself, resulting in a decrease in the water content.

[0013] Accordingly, there has been a strong demand for a crosslinked polyvinyl alcohol ophthalmic lens which can be easily produced, has excellent shape stability, and has excellent mechanical strength and maintains a high water content.

An object of the present invention is to provide an easy-to-handle lens having a uniform lens surface, a small variation in polymerization composition, a high water content and a high mechanical strength, and excellent lens shape stability in a swollen state after completion. An object of the present invention is to provide a crosslinked polyvinyl alcohol-made ophthalmic lens which can be mass-produced with high quality, has high water content, which is a characteristic of polyvinyl alcohol itself, and has water retention.

[0015]

The crosslinked polyvinyl alcohol ophthalmic lens comprising N-vinylpyrrolidone as a component of the present invention is a vinyl ester represented by the following structural formula (1) and N-vinylpyrrolidone as a crosslinkable component. It is characterized by being obtained by hydrolyzing a copolymer consisting of triallyl (iso) cyanurate or dialylidene pentaerythritol.

[0016] (In the formula, R represents a hydrocarbon group.)

The method for producing a crosslinked polyvinyl alcohol ophthalmic lens using N-vinylpyrrolidone according to the present invention is characterized in that 1 to 30 parts by weight of N-vinylpyrrolidone per 100 parts by weight of the monomer represented by the above structural formula (1) is used. Parts by weight, and triallyl (iso) cyanurate or diarylidenepentaerythritol as a crosslinking component is added in an amount of 0.05 to 10%.
A mixture was prepared by adding a weight part and an ultraviolet polymerization initiator.Then, the mixture was filled in a lens mold, and irradiated with ultraviolet rays to form a lens-shaped copolymer. It is characterized by hydrolysis.

According to this method, since it is possible to polymerize into a lens shape from the beginning with a molding tool in a short time, triallyl (iso) cyanurate or dialylidene pentaerythryl is effectively cross-linked to polyvinyl ester to maintain the lens shape. Think.

Further, since ultraviolet light is used as the polymerization means, the heat applied from the outside of the mold during polymerization is very small, so that the vaporization of vinyl acetate is suppressed, and the completed lens composition is kept uniform.

Further, by copolymerizing N-vinylpyrrolidone with the vinyl ester, N-vinylpyrrolidone can be incorporated at a desired ratio, so that the characteristics of N-vinylpyrrolidone can be utilized as it is. This is an advantage that leads to an improvement in shape stability in a water-containing state after saponification and an improvement in water retention that is a maintenance of a water content.

In addition, when the lenticular copolymer is polymerized, the viscosity is preliminarily polymerized to 20 to 200 centipoise, whereby a good lenticular copolymer having particularly excellent strength can be obtained.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a vinyl ester as a main component of polyvinyl alcohol is represented by the structural formula (1), and the hydrocarbon group represented by R is a C1-C8 alkyl group, alkenyl group, cycloalkyl group. Groups or aryl groups are preferred.

Specifically, a methyl group as an alkyl group,
Examples of the alkenyl group include a vinyl group, a propenyl group, a butynyl group, and a hexajunyl group. Examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group. Examples of the aryl group include a phenyl group.

As the vinyl ester, vinyl acetate in which R is a methyl group is particularly preferable. However, in order to adjust the polymerization rate, monomer viscosity, hydrolysis rate, etc.
A C8 alkyl group, alkenyl group, cycloalkyl group,
A vinyl ester such as an aryl group may be used in combination.

When R is an alkyl group exceeding C8, hydrolysis of the vinyl ester tends to be difficult, and the saponification rate is 80%.
% Of polyvinyl alcohol tends to be difficult to obtain.

Specific examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl acrylate, vinyl methacrylate, and vinyl sorbate.

In the present invention, N-vinylpyrrolidone is involved in the improvement of the shape stability and the water content of the ophthalmic lens in a water-containing state after saponification, and particularly in the improvement of the water retention power. When only vinyl ester was used as the main component, it was difficult to maintain the water-containing state for a long time, and it was not possible to suppress a change in the shape of the ophthalmic lens due to drying in a short time. However, by copolymerizing N-vinylpyrrolidone, it becomes possible to take in the water-retaining property due to the molecular structure of N-vinylpyrrolidone, and it is possible to suppress the disappearance of water held by the ophthalmic lens. There is an advantage that it leads to suppressing.

The reason for using N-vinylpyrrolidone in the range of 1 to 30 parts by weight lies in the properties of N-vinylpyrrolidone itself. N-vinylpyrrolidone has a property such as a high water content, but has a large swelling ratio in a water-containing state, so
If the amount is more than 10 parts by weight, the swelling ratio of the crosslinked polyvinyl alcohol ophthalmic lens after saponification is large, and the strength is reduced accordingly, which is likely to be unsuitable for practical use.

With less than 0.05 parts by weight of triallyl (iso) cyanurate [triallyl cyanurate or triallyl isocyanurate] and diarylidene pentaerythritol as a crosslinking component, crosslinking as a gel after completion of hydrolysis is not possible. This is sufficient, and it is difficult to maintain the shape as an ophthalmic lens. On the other hand, when the amount exceeds 10 parts by weight, the crosslink density becomes too large, and not only a soft ophthalmic lens is not obtained in a water-containing state, but also the water content decreases. Therefore, in the present invention, 0.05 to 10 parts by weight, preferably 0.06 to 10 parts by weight.
Used in 5 parts by weight.

The mold used in the present invention is polyethylene,
It is made of plastic such as polypropylene, polystyrene, ABS resin, glass, or the like, and has high optical precision. Further, in the case of a vinyl ester having a small number of carbon atoms of R such as vinyl acetate, it is necessary to pay sufficient attention to the airtightness of the mold because it is easily vaporized.

The polymerization method is radical polymerization by ultraviolet irradiation. In the method by thermal polymerization using a mold, when the vaporization of a vinyl ester such as vinyl acetate progresses due to heat before the polymerization starts, when the air density of the mold is high, or when the internal pressure of the mold is too high. May cause rupture or the like. In this respect, the control of polymerization heat is relatively easy in the polymerization by ultraviolet rays as compared with the thermal polymerization method.

In the present invention, the ultraviolet light in the mold
It is also important to control the polymerization reaction caused by the reaction.
In other words, by polymerization using a mold with a small amount of monomer used
Is a polymerization reaction between vinyl ester and N-vinylpyrrolidone
Speed and crosslinker triallyl (iso) cyanurate
Reaction rate of pentaerythritol and diarylidene pentaerythritol
Strict adjustment is required. About this,
By adjusting the amount of initiator and UV irradiation
Can be achieved. That is, as the polymerization reaction conditions by both,
Means that the polymerization initiator is 5,000 to 25,000 ppm
Then, as the irradiation energy of ultraviolet rays,
10,000-70,000 mJ / cm ^Two Within the range
It is preferred to do so.

In the polymerized polymer, it is difficult to generate a temperature which greatly exceeds the softening point in the polymerization by ultraviolet rays.
Although peeling of the vinyl ester copolymer is easy, it is also recommended that the entire mold be cooled to a temperature lower than the softening point of the vinyl ester copolymer and taken out of the mold.

Examples of the UV polymerization initiator include diethoxyacetophenone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, and 2-hydroxy-2-methyl-1-phenylpropane-1-. On, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 1-hydroxycyclohexyl-phenylketone, 2-benzyl-2-dimethylamino-1-morpholinophenyl) -butanone, benzyl Dimethyl ketal and the like can be mentioned.

The lens-shaped vinyl ester copolymer polymerized in the mold becomes a desired crosslinked polyvinyl alcohol ophthalmic lens by hydrolysis.

The method of hydrolysis is not particularly limited, but the lens-shaped molding is immersed in an alkaline aqueous solution and reacted. For example, it is preferable that the lens-shaped molded body is swollen in advance with a lower alcohol such as methanol, then immersed in a mixed solution of an aqueous sodium hydroxide solution and a lower alcohol such as methanol, and subjected to hydrolysis under heating. At this time, if the hydrolysis is not sufficiently performed, not only the high water content, which is a feature of the present invention, but also the transparency of the polymer tends to be low, which tends to make it difficult to use as an ophthalmic lens. The decomposition ratio is preferably 80% or more of the vinyl ester.

As described above, according to the present invention, it is possible to easily provide an ophthalmic lens made of crosslinked polyvinyl alcohol having excellent flexibility, high water content, water retention, and excellent shape stability and lens quality. .

[0038]

EXAMPLE 1 A mixture of 18 g of vinyl acetate, 2 g of N-vinylpyrrolidone and 0.3 g of triallylisocyanurate was added to a mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one (2-hydroxy-2-methyl-1-phenylpropan-1-one) as an ultraviolet initiator. (DAROCUR1173, manufactured by Nippon Ciba Geigy) was added and the mixture was sufficiently stirred. Thereafter, the mixture was filled in a polypropylene mold, and irradiated with ultraviolet light irradiation energy of 15.3 mW / cm ² for 30 minutes using a high-pressure mercury lamp in an ultraviolet irradiation device (integrated light amount: 27540 mJ / cm ² ). A lenticular polymer was obtained. Furthermore, methanol and distilled water are mixed in 2:
8 was added to the aqueous solution mixed at a ratio of 1.0.
The lens-shaped molded product was immersed in the solution so as to have a molar concentration, and hydrolyzed at 40 ° C. for 2 hours or more. Thereafter, the lens-shaped molded body was taken out and thoroughly washed with a large amount of water to obtain a crosslinked polyvinyl alcohol-made ophthalmic lens.

It was confirmed by infrared spectrophotometry that the saponification of vinyl ester to vinyl alcohol had progressed about 80% or more in the lens-shaped molded article. This lens has a light transmittance of 95% or more and a water content of 7%.
It was 2%, and no roughening of the lens surface was observed. The swollen state lens after completion was soft, had excellent shape stability, was easy to handle, and had excellent quality.

Example 2 Crosslinking was carried out in the same manner as in Example 1 except that 20,000 ppm of an ultraviolet initiator DAROCUR 1173 was added to a mixture of 14 g of vinyl acetate, 6 g of N-vinylpyrrolidone, and 0.3 g of triallylisocyanurate. An ophthalmic lens made of polyvinyl alcohol was obtained. In the lens-shaped molded product, it was confirmed by an infrared spectrophotometer that saponification of vinyl ester to vinyl alcohol had progressed by about 80% or more. This lens has a light transmittance of 95% or more, a water content of 76%, no roughness on the lens surface, and the finished swollen lens is flexible, has excellent shape stability, is easy to handle and has good quality. Was excellent.

Example 3 16 g of vinyl acetate, 2 g of vinyl propionate, 2 g of N-vinylpyrrolidone, 0.3 of triallylisocyanurate
A crosslinked polyvinyl alcohol-made ophthalmic lens was obtained in the same manner as in Example 1, except that 20,000 ppm of the UV initiator DAROCUR 1173 was added to the mixed solution of the g.
In the lens-shaped molded product, it was confirmed by an infrared spectrophotometer that saponification of vinyl ester to vinyl alcohol had progressed by about 80% or more. This lens has a light transmittance of 95% or more, a water content of 74%, and no rough surface of the lens. The swollen state of the finished lens is flexible, has excellent shape stability, is easy to handle, and has high quality. Was excellent.

Example 4 The same method as in Example 1 except that 20,000 ppm of DAROCUR 1173 was added to a mixture of 18 g of vinyl acetate, 2 g of N-vinylpyrrolidone and 0.3 g of diarylidenepentaerythritol. Thus, a crosslinked polyvinyl alcohol ophthalmic lens was obtained. The lens-shaped molded body,
It was confirmed by infrared spectrophotometry that the saponification of vinyl ester to vinyl alcohol progressed by about 80% or more. This lens has a light transmittance of 95% or more, and has a water content of 72%. No roughening of the lens surface is observed. The swollen state lens after completion is flexible, has excellent shape stability, is easy to handle, and has good quality. Was excellent.

Example 5 A mixture of 18 g of vinyl acetate, 2 g of N-vinylpyrrolidone and 0.3 g of diarylidenepentaerythritol was added with
After adding 0.05 part by weight of 2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) and replacing the atmosphere in the vessel with nitrogen, the temperature was raised to 50 ° C. with stirring to carry out prepolymerization. When the viscosity became 50 to 70 centipoise, a polymerization inhibitor hydroquinone was added so as to have a concentration of 400 ppm, and further cooled to -10 ° C to terminate the polymerization. To 100 parts by weight of the monomer mixture, an ultraviolet initiator DAROC was added.
A crosslinked polyvinyl alcohol ophthalmic lens was obtained in the same manner as in Example 1 except that 20,000 ppm of UR1173 was added. In the lens-shaped molded product, it was confirmed by an infrared spectrophotometer that saponification of vinyl ester to vinyl alcohol had progressed by about 80% or more. This lens has a light transmittance of 95% or more and a water content of 7%.
It was 0%, and no roughening of the lens surface was observed. The swollen lens after completion was soft, had excellent shape stability, was easy to handle, and had excellent quality.

Comparative Example 1 Vinyl acetate 20 g, triallyl isocyanurate 0.3
g, UV initiator DAROCUR 1173 at 20,000
A crosslinked polyvinyl alcohol ophthalmic lens was obtained in the same manner as in Example 1 except that 0 ppm was added. In the lens-shaped molded product, it was confirmed by an infrared spectrophotometer that saponification of vinyl ester to vinyl alcohol had progressed by about 80% or more. This lens had a light transmittance of 95% or more and a water content of 72%, and showed no roughness on the lens surface. However, it dried quickly and was poor in water retention.

<Water retention test> From a state completely hydrated with physiological saline, the mixture was allowed to stand at room temperature 25 ° C and humidity 50%.
The dry state of the lens surface was determined from the change in the water content after 10 minutes. As a criterion, the change amount within 10% was represented by ◎, the change amount within 20% was represented by ○, the change amount within 30% was represented by Δ, and the change amount was indicated by ×. As a result, as shown in the following table, those having a large amount of change had a rapid drying of the lens surface and poor water retention.

[0046]

Regarding the shape, since the copolymer is a copolymer of N-vinylpyrrolidone, vinyl acetate and a cross-linking agent of triallylisocyanurate or diarylidenepentaerythritol, Examples 1 to 5 have good water retention and good shape. Met. In Comparative Example 1, since N-vinylpyrrolidone was not used, the water retention was poor. Therefore, the lens surface was easily dried in the air, and the shape was changed accordingly.

[0048]

The present invention provides a crosslinked polyvinyl alcohol ophthalmic lens having high transparency and high water content, and
The crosslinked polyvinyl alcohol ophthalmic lens is added with a crosslinking agent and an ultraviolet polymerization initiator to a mixture of vinyl ester and N-vinylpyrrolidone, and polymerized in a short time with ultraviolet rays in a lens shape in a molding die in which polymerization conditions are controlled, The swelled lens after completion has excellent shape stability and water retention, so it is easy to handle and practical, and enables a method of mass-producing with a constant quality.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 226: 06 224: 00) (72) Inventor Kenji Uno 2-40-2 Hongo, Bunkyo-ku, Tokyo Seed Co., Ltd.

Claims (5)

[Claims] 1. A copolymer obtained by hydrolyzing a copolymer comprising a vinyl ester represented by the following structural formula (1), N-vinylpyrrolidone, and triallyl (iso) cyanurate or diarylidenepentaerythrit as a crosslinking component. An ophthalmic lens made of crosslinked polyvinyl alcohol, characterized in that: (In the formula, R represents a hydrocarbon group.) 2. The vinyl ester according to claim 1, wherein R is C1 to C8.
The crosslinked polyvinyl alcohol ophthalmic lens according to claim 1, which is an alkyl group, an alkenyl group, a cycloalkyl group, or an aryl group. 3. The crosslinked polyvinyl alcohol ophthalmic lens according to claim 1, wherein the vinyl ester is a mixture of at least two vinyl esters. 4. N-vinylpyrrolidone is mixed in an amount of 1 to 30 parts by weight, based on 100 parts by weight of all monomers, 0.05 to 10 parts by weight of triallyl (iso) cyanurate or diarylidenepentaerythritol as a crosslinking component, and ultraviolet rays. Preparing a mixture to which a polymerization initiator is added, filling the mixture into a lens mold, irradiating ultraviolet rays to form a lenticular copolymer, and then hydrolyzing the lenticular copolymer. A method for producing an ophthalmic lens made of crosslinked polyvinyl alcohol, characterized in that: 5. The method according to claim 1, wherein the viscosity of the monomer mixture is previously set at 20.
A method for producing an ophthalmic lens made of crosslinked polyvinyl alcohol, which is obtained by the production method according to claim 4 after pre-polymerization to 200 centipoise.