JPH10104554A - Highly hydrous contact lens and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly hydrous contact lens which is optically transparent and has excellent mechanical strength and a process for producing the same. SOLUTION: This method for producing the hydrous soft contact lens consists in polymerizing a monomer for the contact lens in the presence of a diluting agent for the monomer and substituting the diluting agent continued in the resulted polymer with an aq. soln. The diluting agent described above is one or >=2 kinds of the compds. selected from a group consisting of triethylene glycol, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether. The hydrous contact lens consists of the copolymer of the monomer for the contact lens contg. (1) >=2 kinds of hydrophilic monomers selected from a group consisting of 2-hydroxyethyl methacrylate, N-vinl-2-pyrrolidone and N,N-dimethyl acrylamide, (2) acryl methacrylate and (3) a crosslinkable monomer as essential components and the aq. soln. The moisture contact is 50 to 70% and the thrust-through strength is >=1100gf/mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a liquid having a water content of 50-7.
The present invention relates to a high water content soft contact lens of 0% and a method for producing the same. More specifically, by polymerizing the monomer mixture in the presence of a diluent that can be replaced with water or a saline solution, and replacing the diluent contained in the obtained polymer with water or a physiological saline solution, The present invention relates to a method for obtaining a hydrated contact lens, particularly to a method for producing a highly hydrated contact lens having excellent transparency and high mechanical strength.

[0002]

2. Description of the Related Art It is known that soft contact lenses have a good feeling of wearing due to the flexibility of the material. In particular, it is said that a soft contact lens having a higher water content has a better wearing feeling. However, high water content soft contact lenses generally have the disadvantage of low strength and are therefore difficult to handle. Usually, soft contact lenses are manufactured by cutting and polishing, which is obtained by cutting and polishing a copolymer and swelling the copolymer in water. When a high water content soft contact lens is manufactured by this cutting and polishing method, it is not easy to increase the achievement rate of a target lens because the copolymer absorbs moisture in the air during processing. In addition, the cutting and polishing method, in addition to these problems, includes many steps that require precision, such as cutting and polishing the base curve, front curve, and edge portion, etc., which is not suitable for mass production of contact lenses. is there.

On the other hand, as a method of manufacturing a contact lens which does not require cutting and polishing and is suitable for mass production, a method of cast polymerization using a mold for manufacturing a contact lens is known. However, in this method, in interfacial polymerization in a mold having a small volume, the polymerization is inhibited by the influence of the oxygen molecules adsorbed on the mold, and the strength and the transparency may decrease, particularly, cloudiness may occur. Further, when a high water content soft contact lens is manufactured by this method, there is also a problem that precise control of lens parameters is difficult due to a high elongation rate in a swelling process of the lens. Therefore, recently, a method for producing a high water content soft contact lens having a constant parameter using this cast polymerization has been used. In this method, a contact lens is obtained by polymerizing a lens monomer in the presence of a diluent for a monomer that does not inhibit polymerization of the monomer, and replacing the obtained polymer with water, physiological saline, or the like. According to this method, the swelling ratio of the lens can be suppressed, and precise control of lens parameters becomes easy.

[0004] For example, JP-A-6-289331 (hereinafter referred to as Prior Art 1) discloses that a hydrophilic monomer is polymerized in the presence of an aqueous solution selected from pure water, dioxane, and dimethyl sulfoxide. Discloses a method of casting and polymerizing a contact lens. The content of the water-soluble solution in the polymerization mixture is 100
It is recommended that the amount be 30 to 80 parts by weight per part by weight. Japanese Patent Publication No. 4-49093 (hereinafter referred to as Prior Art 2) discloses an acrylic or methacrylic monomer.
A method is disclosed for static casting contact lenses by polymerizing in the presence of a mixture of water-replaceable borate esters. Examples of borate esters include borate esters of glycerol, sorbitol, propylene glycol or mixtures thereof.

Japanese Patent Application Laid-Open No. 4-110311 (hereinafter referred to as Prior Art 3) discloses that a major proportion of a hydrophilic (meth) acrylate ester monomer having an alkyl group of at least 4
It discloses casting polymerization in the presence of an alkyl methacrylate containing two carbon atoms and a diluent capable of replacing the bridging monomer with water to obtain a contact lens.
Here, the diluent is a boric acid ester of a certain dihydric alcohol. U.S. Pat. No. 3,699,089 (hereinafter, "U.S. Pat.
Prior Art 4) discloses spin casting soft contact lenses by polymerizing a hydrophilic monomer in the presence of water or a water-miscible solvent. Here, the water-miscible solvent is ethylene glycol, glycerol,
And dioxane. As is clear from the above-mentioned prior art disclosure, the solvent or diluent is appropriately selected according to the type of the monomer in order to obtain a contact lens that is optically transparent and has excellent mechanical strength.

According to the study of the present inventors, in the presence of the diluent used in the method disclosed in the above prior art,
By casting and polymerizing a monomer composed of a hydrophilic monomer and an alkyl methacrylate and substituting a diluent (or solvent), it is possible to obtain the above-mentioned contact lens having optical transparency and excellent mechanical strength. It was extremely difficult. The prior art methods described above only provide lenses that are optically opaque or have low mechanical strength.

Accordingly, an object of the present invention is to provide a highly water-containing soft contact lens comprising a polymer of a monomer comprising a hydrophilic monomer and an alkyl methacrylate, which is optically transparent and has excellent mechanical strength. And a method of manufacturing the same.

[0008]

DISCLOSURE OF THE INVENTION In view of the above prior art, the present inventors have developed a soft contact lens having high water content and excellent transparency and high mechanical strength by cast polymerization suitable for mass production. Diligent research was conducted to see if it could be manufactured. As a result, they have found that the above problems can be solved by using triethylene glycol, diethylene glycol monomethyl ether, and triethylene glycol monomethyl ether as diluents, and have completed the present invention.

That is, the present invention provides a hydrated soft contact lens by polymerizing a contact lens monomer in the presence of a monomer diluent and replacing the diluent contained in the obtained polymer with an aqueous solution. Wherein the diluent is one or more compounds selected from the group consisting of triethylene glycol, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The present invention is a method for producing a hydrated soft contact lens by polymerizing a contact lens monomer in the presence of a monomer diluent and replacing the diluent contained in the obtained polymer with an aqueous solution. The method itself using such a diluent is known, and in the method of the present invention, the polymerization method and conditions, the aqueous solution to be replaced with the diluent, the replacement method, and the like can use the conventional methods as they are. A specific method will be described later.

A feature of the present invention is that the diluent is one or more compounds selected from the group consisting of triethylene glycol, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether. By using these diluents, when replacing the diluent in the contact lens with an aqueous solution such as water or physiological saline after polymerization to obtain a hydrated contact lens,
The swelling ratio of the lens can be kept low, and the lens parameters can be uniformly and precisely controlled. Further, these diluents effectively remove the heat of polymerization generated during the polymerization in the mold, and exhibit the effect of obtaining a contact lens having excellent uniformity. The monomer diluent is suitably present in the range of 20 to 40% by weight based on the total amount of the monomer diluent and the contact lens monomer. If the amount of the monomer diluent is less than 20% by weight, it tends to be difficult to suppress the swelling ratio of a water-containing contact lens to a low level. If it exceeds 40% by weight, the strength of the obtained lens tends to decrease. In particular, the amount of the diluent for monomers is preferably in the range of 25 to 35% by weight.

In the method of the present invention, the monomer for contact lens is (1) two or more hydrophilic monomers selected from the group consisting of 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone and N, N-dimethylacrylamide. It is appropriate to contain the monomer, (2) alkyl methacrylate, and (3) a crosslinkable monomer as main components. The hydrophilic monomer is used for adjusting the water content of the contact lens. In particular, by using two or more hydrophilic monomers, a contact lens having a high water content can be obtained. These hydrophilic monomers are suitably in the range of 50 to 75% by weight based on the total amount of the diluent for monomers and the monomer for contact lenses. If the amount of the hydrophilic monomer is less than 50% by weight, it becomes difficult to obtain the objective high water content soft contact lens,
On the other hand, if it exceeds 75% by weight, the strength of the obtained lens tends to decrease. In particular, the amount of hydrophilic monomer is 55
It is preferably about 70% by weight.

[0013] Alkyl methacrylate (hereinafter referred to as RMA) is used for the purpose of improving the mechanical strength of a lens. As RMA, for example, methyl methacrylate, ethyl methacrylate or both can be used. The RMA is suitably in the range of 3 to 20% by weight based on the total amount of the monomer diluent and the contact lens monomer. If the amount of RMA is less than 3% by weight, the mechanical strength cannot be sufficiently improved, and if it exceeds 20% by weight, the flexibility of the lens decreases or the surface water leakage of the lens decreases. In some cases. In particular, the amount of RMA is preferably 5 to 18% by weight.

[0014] Crosslinkable monomers are used for the purpose of preventing deformation of contact lenses and improving mechanical strength. The crosslinkable monomer is at least one monomer selected from the group consisting of di (meth) acrylate of a polyhydric alcohol and at least one monomer having an allyl group in the molecule. Examples of the poly (alcohol) di (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate. Can be. Examples of the monomer having at least one allyl group in the molecule include allyl (meth) acrylate, diallyl maleate, diallyl phthalate, diallyl isophthalate, triallyl isocyanurate and the like. In addition, in this specification, "(meth) acrylate" means both acrylate and methacrylate. The amount of the crosslinkable monomer used is suitably in the range of 0.1 to 2% by weight based on the total amount of the hydrophilic monomer and the alkyl methacrylate. If the amount is less than 0.1% by weight, the effect of introducing the crosslinkable monomer is unlikely to be exhibited, and if it exceeds 2% by weight, the lens tends to become brittle and the mechanical properties tend to deteriorate. In particular, the amount of crosslinking monomer is between 0.25 and 1
% By weight.

Further, in the present invention, as a copolymer component, for example, a polymerizable ultraviolet absorber, a polymerizable dye, or the like can be used in order to impart an ultraviolet absorbing ability to the obtained contact lens or to color the contact lens. Specific examples of the polymerizable ultraviolet absorber include 5-chloro-2- [2-hydroxy-5
-(β-methacryloyloxyethylcarbamoyloxyethyl)] phenyl-2H-benzotriazole, 2- [2-hydroxy-5- (β-methacryloyloxyethylcarbamoyloxyethyl)] phenyl-2H-benzotriazole, 5-
Chloro-2- [2-hydroxy-4- (p-vinylbenzyloxy-2)
-Hydroxypropyloxy)] phenyl-2H-benzotriazole and the like.

Specific examples of the polymerizable dye include 1,4-bis (4-vinylbenzylamino) anthraquinone, 1-p-hydroxybenzylamino-4-p-vinylbenzylaminoanthraquinone, 1-anilino-4- Methacryloylaminoanthraquinone and the like. When coloring the contact lens of the present invention, these polymerizable dyes are not used, and the leuco body of the dye is immersed in a vat dye bath to sufficiently impregnate the entire lens, and then immersed in an oxidation bath to convert the leuco body to an oxidized body. The vat dyeing method of fixing by use may be used. In addition, phthalocyanine dyes such as Alcian Blue 8GX and Alcian Green 2GX can be used as a coloring agent. Since the compounding amount of the polymerizable ultraviolet absorber and the polymerizable dye is affected by the thickness of the lens, the amount is preferably 5% by weight or less, particularly preferably 0.02 to 3% by weight of the copolymer component. is there. If the compounding amount exceeds 5% by weight, the mechanical strength of the obtained contact lens may be reduced, and in consideration of the toxicity of the ultraviolet absorber and the dye, it is suitable as a soft contact lens that comes into direct contact with a living body. Tends to disappear.

In producing a soft contact lens according to the present invention, first, a polymerization initiator is added to a mixture containing the above-mentioned diluent and monomer, and the mixture is sufficiently stirred to obtain a homogeneous monomer mixture. As the radical initiator used here, peroxides such as lauroyl peroxide, cumene hydroperoxide, and benzoyl peroxide, which are known as general radical initiators,
Examples include azobisvaleronitrile and azobisisobutyronitrile. The use amount of these initiators is suitably in the range of 0.1 to 1% by weight based on the total amount of the hydrophilic monomer and the alkyl methacrylate.

The above monomer mixture is polymerized after being injected into a mold for producing a contact lens. This mold is a combined mold having convex and concave curvatures, and can be made of a material such as metal, glass, or resin. However, it is preferable that the material has good releasability of the polymer and excellent solvent resistance and heat resistance. Further, a resin mold is preferable because a mold having a shape required for a desired lens design can be easily manufactured. These resin materials are preferably selected from those having low molding shrinkage, good surface transferability from a mold, and excellent dimensional accuracy and solvent resistance. Examples of such resin materials include polyethylene, Polypropylene, polymethylpentene (TPX), polysulfone, polyphenylene sulfide, cyclic olefin-based copolymer (for example, “Apel
(APL) ", Mitsui Petrochemical Co., Ltd.," ZEONEX "Nippon Zeon Co., Ltd.), olefin / maleimide copolymer, and the like. After depressurizing the mold sufficiently to remove substances affecting the reaction such as moisture and oxygen on the mold surface and purging with an inert gas such as nitrogen or argon,
The monomer mixture is poured into the mold. Injecting the monomer mixture is preferably performed in an atmosphere of an inert gas such as nitrogen or argon.

As a polymerization method, for example, the temperature is raised stepwise or continuously in a temperature range of 25 to 120 ° C.,
A method of completing polymerization in 24 hours can be mentioned. At this time, it is preferable that the polymerization is performed in an atmosphere of an inert gas such as nitrogen or argon in the polymerization furnace and the polymerization is performed under the atmospheric pressure or the pressurized state. In addition, at the time of polymerization, after blending a photopolymerization initiator, it is also possible to apply a photopolymerization method using ultraviolet light, visible light, or the like. After the completion of the polymerization, the copolymer is taken out of the mold, and the diluent contained in the copolymer is replaced with an aqueous solution to obtain a hydrated contact lens. The aqueous solution to be replaced with the diluent may be an aqueous solution usually contained in a hydrated contact lens, and examples thereof include water, physiological saline, and a preservative for soft contact lenses. In order to efficiently remove the unpolymerized monomer and diluent in the copolymer, first, the lens may be replaced with an alcohol having a high degree of swelling or an alcohol / water mixture, and then replaced with the above aqueous solution. it can.

The present invention also includes a novel hydrated contact lens. The hydrated contact lens of the present invention is a hydrated contact lens comprising a copolymer of a monomer for a contact lens containing the hydrophilic monomer, alkyl methacrylate and a crosslinkable monomer as main components and an aqueous solution. The hydrophilic monomers, alkyl methacrylates and crosslinkable monomers and the amounts used (copolymer amounts) thereof are the same as those described in the above production method. Further, the type of the aqueous solution is the same as that described in the above manufacturing method. In addition, the water-containing contact lens of the present invention has excellent mechanical strength with a punch-out strength of 1100 gf / mm or more, despite its high water content of 50 to 70%. The water content of the water-containing contact lens of the present invention is preferably 55 to 70% from the viewpoint of excellent wearing feeling.

Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited to these examples.

Example 1 2-Hydroxyethyl methacrylate (hereinafter referred to as HEMA) was placed in a glass sample bottle having a capacity of 100 ml.
75 g (37.5% by weight), 13.5 g (27% by weight) of N-vinyl-2-pyrrolidone (hereinafter referred to as NVP), 5.25 g of ethyl methacrylate (hereinafter referred to as EMA)
(10.5% by weight), triethylene glycol (hereinafter, referred to as
12.5 g (25% by weight) of TEG) and 0.1875 g of diallyl maleate (hereinafter referred to as DAM) (HE
0.5% by weight based on the total amount of MA, NVP and EMA) and 2,2′-azobisisobutyronitrile (hereinafter referred to as AI)
0.15 g (referred to as BN) (0.4% by weight based on the total amount of HEMA, NVP and EMA) was added thereto, and the mixture was sufficiently stirred to prepare a monomer mixture. The monomer mixture was placed in a polypropylene contact lens-shaped mold, and was placed in a nitrogen atmosphere at a pressure of 2 (kgf / cm ² ) for 25 to 11 hours.
Polymerization was carried out at 0 ° C. for 15 hours. After completion of the polymerization, the polymer was taken out of the mold and immersed in a large amount of distilled water to remove the diluent. Then, the objective contact lens was obtained by immersion in physiological saline. The obtained contact lens was transparent when hydrated, and had good mechanical strength.

Using this contact lens, various physical properties were examined according to the following methods. Table 1 shows the results. Transparency A contact lens in a physiological saline solution at 25 ° C. was visually observed and evaluated based on the following evaluation. [Evaluation criteria] ○: Transparent △: Lightly cloudy ×: Strongly cloudy

Moisture Content When the weight of a contact lens that has reached equilibrium swelling in a physiological saline solution at 25 ° C. after hydration swelling is Ww, and the weight after re-drying (80 ° C., 4 hours) is Dw, the following formula is obtained. The water content was calculated. Water content (%) = {(Ww-Dw) / Ww} × 100 Swelling ratio After polymerization, the diameter of the lens before replacing the diluent is Dd. After swelling by hydration, equilibrium swelling in physiological saline at 25 ° C. Assuming that the diameter of the reached contact lens is Wd, the swelling ratio was calculated by the following equation. Swelling ratio (%) = {(Wd−Dd) / Dd} × 100

Punching Strength A punching rod having a steel ball having a diameter of 1/16 inch attached to the tip of a stainless steel rod was attached to an Instron universal material tester Model 4310, and the lens fixed in a saline solution at 25 ° C. The punching load (g) at the time of breaking of the center portion was measured. However, the values in Table 1 are values obtained by dividing the punching load at break by the center thickness (mm) of the lens. The center thickness of the lens used for the measurement was 0.10
０．１0.12 (mm).

Examples 2 to 10 Contact lenses were obtained in the same manner as in Example 1 except that the composition was changed as shown in Table 1. The obtained contact lens was transparent when hydrated, and had good mechanical strength.

Comparative Example 1 (Japanese Patent Laid-Open No. 6-289331 (Prior Art 1)) In the same manner as in Example 1, except that the TEG used as a diluent was changed to dimethyl sulfoxide (hereinafter referred to as DMSO). I got a contact lens. The obtained contact lens had lower mechanical strength than the contact lens obtained in Example 1.

Comparative Example 2 (Japanese Patent Application Laid-Open No. 4-1103111 (Prior Art 3)) In Example 1, the TEG used as a diluent was changed to diethylene glycol borate ⁽¹⁾ (hereinafter referred to as DEG boric acid). A contact lens was obtained in the same manner as in Example 1. The obtained contact lens was strongly clouded and could not be used as a contact lens. (1) 17% by weight of 82.2% by weight of diethylene glycol.
It was produced by reacting with 8% by weight of boric acid under a vacuum of 10 mmHg at a temperature of 80 ° C. for 4 hours (JP-A-4-110311, ester No. 21 in Table 2).

Comparative Example 3 (Japanese Patent Publication No. 4-49093 (Prior Art 2)) In Example 1, TEG used as a diluent was changed to glycerol borate ⁽²⁾ (hereinafter referred to as Gly boric acid). A contact lens was obtained in the same manner as in Example 1. The resulting contact lens becomes strongly cloudy,
It could not be used as a contact lens. (2) 73.5% by weight of glycerol is 26.5% by weight
Of boric acid at a temperature of 80 ° C. for 4 hours under a vacuum of 10 mmHg (Japanese Patent Publication No. 4-49).
093, diluent of Example 2).

Comparative Example 4 A contact lens was obtained in the same manner as in Example 1, except that the TEG used as a diluent was changed to diethylene glycol (hereinafter referred to as DEG). The obtained contact lens had lower mechanical strength than the contact lens obtained in Example 1.

Comparative Example 5 (US Pat. No. 3,699,089)
No. (Prior Art 4)) A contact lens was obtained in the same manner as in Example 1 except that TEG used as a diluent was changed to ethylene glycol (hereinafter referred to as EG). The obtained contact lens had lower mechanical strength than the contact lens obtained in Example 1.

Comparative Example 6 (US Pat. No. 3,699,089)
No. (Prior Art 4)) In Example 1, TEG used as a diluent was changed to glycerol (hereinafter, referred to as Gly), and a monomer mixture was prepared in the same manner as in Example 1, but EMA and Gly were separated. A uniform monomer mixture could not be obtained.

Comparative Example 7 (System without Diluent) HEMA17.
5g (35% by weight), NVP 25g (50% by weight), methyl methacrylate (hereinafter referred to as MMA) 7.5g
(15% by weight), DAM 0.25 g (HEMA, NV
P, 0.5% by weight based on the total weight of MMA) and AIB
0.2 g of N (0.4% by weight based on the total amount of HEMA, NVP and MMA) was added, and the mixture was sufficiently stirred to prepare a monomer mixture. Thereafter, a contact lens was obtained in the same manner as in Example 1. The resulting contact lens is thin and cloudy,
The swelling ratio was higher than that of the contact lens obtained in Example 1, and the mechanical strength was weaker.

[0034]

[Table 1]

As shown in Table 1, Comparative Examples 1, 4 and 5
Although the swelling ratio was suppressed by using the diluent, the contact lens of No. 1 had low mechanical strength. The contact lenses of Comparative Examples 2 and 3 were cloudy and could not be used as contact lenses. In Comparative Example 6, since the monomer and the diluent were separated, a uniform monomer mixture could not be prepared. Comparative Example 7
Contact lenses are thin and cloudy, and the swelling rate is large because the contact lenses were made without using diluents.
Further, the mechanical strength was weak.

On the other hand, all of the contact lenses of Examples 1 to 10 are transparent, can suppress the swelling ratio as compared with the system using no diluent (Comparative Example 7), and have a higher punch-out strength. It was 1100 gf / mm or more and had high mechanical strength. This is especially true for triethylene glycol, diethylene glycol monomethyl ether,
This is the effect of using a solvent such as triethylene glycol monomethyl ether as a diluent.

[0037]

The contact lens of the present invention has the advantage that it has high water content, has excellent transparency and high mechanical strength, and can be produced by cast polymerization suitable for mass production by the production method of the present invention. There is.

Claims (10)

[Claims] 1. A method for producing a water-containing soft contact lens by polymerizing a contact lens monomer in the presence of a monomer diluent and replacing the diluent contained in the obtained polymer with an aqueous solution. Wherein the diluent is one or more compounds selected from the group consisting of triethylene glycol, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether. 2. The method according to claim 1, wherein the monomer diluent is present in an amount of 20 to 40% by weight based on the total amount of the monomer diluent and the contact lens monomer. 3. The method according to claim 1, wherein the monomer for contact lens is (1) 2-
Contains, as main components, two or more hydrophilic monomers selected from the group consisting of hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone and N, N-dimethylacrylamide, (2) alkyl methacrylate, and (3) a crosslinkable monomer. The production method according to claim 1 or 2, wherein: 4. The monomer for a contact lens contains 50 to 75% by weight of a hydrophilic monomer and 3 to 20% by weight of an alkyl methacrylate based on the total amount of a diluent for a monomer and a monomer for a contact lens. 3. The production method according to 3. 5. The production method according to claim 3, wherein the alkyl methacrylate is methyl methacrylate and / or ethyl methacrylate. 6. The crosslinkable monomer is a polyhydric alcohol di (meth) acrylate or at least one monomer selected from the group consisting of monomers having at least one allyl group in the molecule. Any one of
The production method according to the paragraph. 7. The contact lens monomer according to claim 3, wherein the monomer for contact lens contains 0.1 to 2% by weight of a crosslinking monomer based on the total amount of the hydrophilic monomer and the alkyl methacrylate. The production method described in 1. 8. A contact lens-shaped polymer obtained by injecting a mixture of a monomer diluent and a contact lens monomer into a mold and copolymerizing the mixture.
The production method according to any one of the above. 9. A composition comprising: (1) two or more hydrophilic monomers selected from the group consisting of 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone and N, N-dimethylacrylamide; (2) alkyl methacrylate; 3) A water-containing contact lens comprising a copolymer of a contact lens monomer containing a crosslinkable monomer as a main component and an aqueous solution, having a water content of 50 to 70% and a punch-out strength of 1100 gf / mm or more. A water-containing contact lens, characterized in that: 10. A hydrated contact lens produced by the method according to claim 3, wherein the hydrated contact lens has a water content of 50 to 70%.