JPH0580279A - Soft contact lens - Google Patents

Abstract

PURPOSE:To provide the soft contact lens which provides a sufficient sight correcting power in wear, less affects the cornea and is not easily broken in handling of the lens, such as washing by using specific three components as essential components. CONSTITUTION:This lens consists essentially of N-(2-metharyloyl oxyethyl)-2- pyrrolmdone (A), alkyl (meth)acrylate having 1 to 4C alkyl group (B), and fluoroalkyl (meth)acrylate (C). The component A is preferably incorporated into the lens at 20 to 80 pts. wt., the component B at 5 to 40 pts.wt., and the component C at 5 to 40 pts.wt. Further, a hydrophilic monomer is preferably incorporated at <40 pts.wt. in addition to the above-mentioned polymers therein. Such hydrophilic monomer is preferably, for example, 2,3-dihydroxyl propyl methacrylate. The lens which has the mechanical strength to prevent the easy failure of the lens during handling of the lens, such as washing, has the sufficient optical performance for correction of the astigmatism and has the high safety to substantially prevent the sticking of stains and to suppress the propagation of bacteria is obtd. in this way.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a soft contact lens having excellent optical performance and a composition thereof. Furthermore, N- (2-methacryloyloxyethyl) -2-pyrrolidone, an alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms (hereinafter, acrylate and methacrylate are collectively referred to as (meth) acrylate), and As it contains fluoroalkyl (meth) acrylate, it not only has excellent oxygen permeability,
The present invention relates to a soft contact lens which is less likely to be contaminated by tear fluid or the like during wearing and has little toughness when handling the lens because it has toughness.

[0002]

2. Description of the Related Art In recent years, soft contact lenses have been widely used by people who have not been able to wear conventional hard contact lenses because of their good wearing comfort. Most of the currently popular soft contact lenses are those having 2-hydroxyethyl methacrylate as a main component and those having N-vinyl-2-pyrrolidone as a main component.

Generally, a soft contact lens is soft and has a good feeling to wear, but since it is flexible, it has a problem that its shape is likely to change on the cornea during wearing, and the expected optical performance cannot be obtained. If the shape of the lens changes on the cornea, it becomes impossible to correct strong corneal astigmatism, and the required power may not be obtained. Further, as a drawback of the soft contact lens, easiness of breakage when handling the lens has become a problem. Regarding the improvement of mechanical strength, a soft contact lens containing 2,3-dihydroxypropyl methacrylate and methyl methacrylate as main components has been proposed as a material having relatively high rigidity (Japanese Patent Publication No. 62-32456) and is commercially available. There is. on the other hand,
Several proposals have been made for improving the stain resistance, for example, Japanese Patent Publication No. 62-62323 proposes a soft contact lens containing alkylene glycol monomethacrylate and a specific fluorine-containing monomer as main components. ..

JP-A-63-295611 discloses a soft contact lens containing a silicon-containing (meth) acrylate for the purpose of improving oxygen permeability. Further, Japanese Patent Laid-Open No. 63-293520 discloses that
Disclosed is a contact lens containing dimethylacrylamide and fluoroalkyl (meth) acrylate as main components, which has excellent mechanical strength, stain resistance, and oxygen permeability. Furthermore, as a non-hydrous material having high oxygen permeability, a soft contact lens made of a silicone rubber made of polyorganosiloxane has been developed and put on the market. In addition to these, to improve oxygen permeability,
For example, JP-A-54-29660 discloses a methacrylate compound having a hydrophilic group such as a hydroxyl group or a sulfonyl group and a methacrylate compound having a long-chain fluoroalkyl group, and JP-B-60-25766.
The publication proposes a composition comprising a fluoroalkyl acrylate, an alkyl methacrylate, some cross-linking agent and a wetting monomer.

[0005]

The problems of the soft contact lens are that the shape of the soft contact lens is likely to change on the cornea during wearing, the expected optical performance is not obtained, stains easily adhere, and bacteria and fungi propagate. It is easy to handle, complicated to handle, weak in strength, and easily damaged. Due to these problems, soft contact lenses have not been widely used in spite of a good feeling of wearing, and some questions have been raised regarding safety.

Focusing on these problems, as a material having relatively high rigidity and excellent optical performance, Japanese Examined Patent Publication No. 62-3245.
No. 6 discloses a soft contact lens produced by copolymerization of 2,3-dihydroxypropyl methacrylate and methyl methacrylate. Among the conventional techniques, contact lenses made of a copolymer having 2-hydroxyethyl methacrylate as a main component, which is now widely used, are very flexible and have a good wearing feeling. However, due to its softness, the optical surface is constantly changed when the eyeball moves or blinks during wearing, so that the expected optical performance cannot be obtained. If the lens shape changes on the eyeball, it is impossible to correct the strong corneal astigmatism, and it may not be possible to obtain appropriate and reliable visual acuity. In this regard, the soft contact lens produced by the copolymerization of 2,3-dihydroxypropyl methacrylate and methyl methacrylate has a relatively high rigidity and therefore has only a small change in the optical surface and has excellent optical performance. However, correction of corneal astigmatism with soft contact lenses has become possible to some extent. However, while this contact lens has high rigidity, the toughness of the material is small and the contact lens is fragile, so that there is a problem in that the contact lens is easily damaged during handling.

Next, as a problem of the soft contact lens, there is a tendency to get stains, and the technique as described above is disclosed as a material which hardly stains, but it is still not sufficient. That is, the composition disclosed in Japanese Examined Patent Publication No. 62-62323 is one in which a fluorine-containing monomer is added to conventionally known 2-hydroxyethyl methacrylate, and the addition amount of the latter is 10% by weight depending on the mixing ratio. If it exceeds the percentage, the stain resistance can be improved, but the amount of the fluorine-containing monomer added at that time causes a decrease in the strength of the raw material, and there is a risk of breakage.

Furthermore, oxygen permeability is an important factor required for contact lenses. If the oxygen permeability is poor, the cornea lacks the necessary oxygen, and if it is worn for a long time, it may cause hyperemia or even impair corneal metabolism. Regarding this oxygen permeability, JP-A-63-29
The soft contact lens containing a silicon-containing (meth) acrylate described in Japanese Patent No. 5611 has improved oxygen permeability but insufficient strength. On the other hand, the contact lens containing dimethylacrylamide and fluoroalkyl (meth) acrylate as main components described in JP-A-63-293520 has a high water content of N-vinyl-2-.
Compared to contact lenses containing pyrrolidone as the main component,
Poor oxygen permeability. On the other hand, on the other hand, the oxygen permeability is greatly improved by making the contact lens high in water content, but the mechanical strength tends to decrease as the water content increases. In particular, contact lenses containing N-vinyl-2-pyrrolidone as a main component have poor copolymerizability with other polymerizable monomers added to improve strength, which is also a cause of insufficient strength. It is one.

As another example, JP-A-54-2
Nos. 9660 and 60-25766 propose a composition containing a hydroxyl group-containing or sulfonyl group-containing hydrophilic methacrylate compound or alkyl methacrylate and a fluorine-containing monomer, and further a small amount of a crosslinking agent and a wetting monomer. However, even in these cases, the strength is insufficient, which is a practical problem. Particularly, in the case of a soft contact lens, unlike a hard contact lens, it deforms along the shape of the cornea of the eye and adheres exactly, so oxygen permeability and stain resistance are important, and improvements have been made to this. However, while the oxygen permeability and the stain resistance are improved, it cannot be said that the mechanical strength is practically sufficient.

The advantages and problems of the current soft contact lens have been described above, but the present invention is aimed at obtaining a soft contact lens having excellent optical performance and has sufficient oxygen permeability. By using a material that has excellent stain resistance and copolymerizability with various polymerizable monomers, it is possible to overcome the brittleness of the material and to make a hydrous soft contact lens with sufficient mechanical strength. Is the subject. That is, in wearing a soft contact lens, sufficient visual acuity correction power can be obtained, the cornea is less affected, and when handling the lens such as cleaning,
The object is to obtain a safe contact lens composition which is not easily damaged.

[0011]

That is, the soft contact lens of the present invention is characterized by containing the following A, B and C as essential components. A: N- (2-methacryloyloxyethyl) -2-pyrrolidone B: Alkyl (meth) having an alkyl group having 1 to 4 carbon atoms
Acrylate C: Fluoroalkyl (meth) acrylate Further, the components A, B and C are 20 to 80 parts by weight of the component A, 5 to 40 parts by weight of the component B, and 5 to 40 parts by weight of the component C. It is characterized by being.
Furthermore, it is characterized in that it contains less than 40% by weight of a hydrophilic monomer in addition to the above essential components, and the hydrophilic monomer is, for example, 2,3-dihydroxypropyl methacrylate. is there. Furthermore, it is characterized in that it contains less than 5% by weight of a cross-linking agent in addition to the above essential components.

A more detailed description will be given. Here, N of A component
-(2-methacryloyloxyethyl) -2-pyrrolidone is a basic skeleton for making the present soft contact lens hydrophilic. Conventionally used N-vinyl-2-
Pyrrolidone was not good in copolymerizability with various polymerizable monomers represented by (meth) acrylic acid ester which is generally used as a raw material for contact lenses. On the other hand, N- (2-methacryloyloxyethyl) -2-pyrrolidone of this component has a significantly improved copolymerizability with various polymerizable monomers by changing the vinyl group to a methacryloyl group, and the obtained copolymer Not only is the strength of the coalescence improved, but the flexibility of the selection of usable copolymerizable monomers is increased. When the amount of this component used is relatively large, the water content of the resulting copolymer is increased and the oxygen permeability is improved, but the mechanical strength and stain resistance are reduced. On the other hand, when the amount used is small, the water content decreases and sufficient oxygen permeability cannot be obtained, which is not preferable.

Next, the alkyl (meth) acrylate as the B component will be described. For example, those represented by the following general formula can be given.

[0014]

[Chemical 1]

(In the formula, X represents a hydrogen atom or a methyl group, and Y represents a linear or branched alkyl group having 1 to 4 carbon atoms.) Here, if Y has too many carbon atoms, the copolymer It is not preferable because the coalescence becomes cloudy and becomes brittle against a force such as pulling. The above-mentioned polymer of alkyl (meth) acrylate is a substance having sufficient mechanical strength and elasticity due to its chemical structure. Examples of the alkyl (meth) acrylate represented by the above general formula include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate and the like. It can be selected and used. When the amount of this component used is relatively large, the water content of the obtained copolymer decreases and the copolymer does not function as a water-containing soft contact lens. On the other hand, when the amount used is small, it is not preferable because sufficient strength cannot be obtained.

Next, the C component fluoroalkyl (meth)
The acrylate will be described. For example, those represented by the following general formula can be given.

[0017]

[Chemical 2]

(Wherein, X is a hydrogen atom or a methyl group, —C _i H _j F _{2i + 1-j} is a linear or branched fluorine-containing group, i is an integer of 1 to 18, and j Represents an integer of 1 to 2i), where the larger the value of i and the more branches, the better the stain resistance and the higher the oxygen permeability. However, conversely, when i becomes large, the shape stability is deteriorated and the production becomes difficult, which is not preferable. Also, j is large,
That is, when the number of fluorine atoms decreases, oxygen permeability decreases, and conversely, when j is 0, the chemical stability of the monomer deteriorates. Therefore, j is preferably 1 to 2i. Examples of the fluoroalkyl (meth) acrylate represented by the above general formula include 2,2,2-trifluoroethyl (meth) acrylate and 2,2,2-trifluoro-1.
-Trifluoromethylethyl (meth) acrylate,
3,3,4,4,5,5,5-heptafluoropentyl (meth) acrylate, 3,3,4,4,5,5,6
6,6-nonafluorohexyl (meth) acrylate,
3,3,4,4,5,5,6,6,7,7,8,8,8
-Tridecafluorooctyl (meth) acrylate,
3,3,4,4,5,5,6,6,7,7,8,8,
9,9,10,10,10-heptadecafluorodecyl (meth) acrylate, 1,1,2,2-tetrahydroperfluorooctadecyl (meth) acrylate, 2,
2,3,3-tetrafluoropropyl (meth) acrylate, 2,2,3,3,4,4,5,5,6,6,7,
7,8,8,9,9-hexadecafluorononyl (meth) acrylate, 2,2,3,3,4,4,5,5
6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11,
There are 11-eicosafluoroundecyl (meth) acrylate and the like, and of these, one kind or two or more kinds can be selected and used. When the amount of this component used is relatively large, the resulting copolymer may become cloudy due to the compatibility with other monomers, and may be easily broken. On the other hand, when the amount used is small, sufficient oxygen permeability cannot be obtained and the stain resistance is also reduced, which is not preferable.

In addition to the above essential components A, B and C, a hydrophilic monomer can be added and is used when controlling the water content or strength. Examples of hydrophilic monomers include:
2,3-dihydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, N, N-dimethylacrylamide, acrylic acid, methacrylic acid and the like can be mentioned. Among them, the use of 2,3-dihydroxypropyl methacrylate is extremely effective in adding rigidity to the material and bringing out excellent optical performance. This is preferably obtained by hydrolyzing glycidyl methacrylate.

The basic components are as described above, but it is desirable to use various crosslinking agents in the range of 0.1 to 5 weight percent for the purpose of maintaining the shape of the contact lens and improving the strength. The purpose of the cross-linking agent is to improve the thermal properties of the copolymer to improve the shape stability, to impart appropriate hardness and elasticity, and to obtain the effects of obtaining good vision correction power as a contact lens. is there. Therefore, the cross-linking agent which is another component will be described. Examples of the cross-linking agent include di- or tri (meth) acrylates of polyfunctional alcohols, and specific examples thereof include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate and triethylene glycol di (meth). Acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butanediol di (meth) acrylate,
Di (meth) acrylates such as pentaerythritol di (meth) acrylate, trimethylolpropane,
Examples thereof include polyhydric esters of (meth) acrylic acid with polyhydric alcohols such as pentaerythritol. The appropriate amount of the cross-linking agent used is 0.1 to 5 weight percent in the polymerizable monomer. If it is less than 0.1% by weight, it becomes difficult to control the water content, which is not preferable. On the other hand, if it exceeds 5% by weight, the oxygen permeability decreases with the decrease in water content, and the flexibility as a soft contact lens decreases, which is not preferable.

In addition to these, additives such as dyeing agents, colorants, and UV inhibitors, and reactive monomers can be added.

Next, the polymerization of these comonomers will be described. Polymerization is carried out by heating or irradiation with active energy rays such as ultraviolet rays in the presence of a usual polymerization initiator. As a specific polymerization initiator, a radical polymerization initiator is desirable, and for example, benzoyl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxypivalate, t -Butylperoxydiisobutyrate, t-butylperoxyisopropyl carbonate, lauroyl peroxide, azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile)
Etc. are used. Further, in the case of irradiation with active energy rays, a photopolymerization initiator such as benzoin ether or a sensitizer is used if necessary. The amount of these initiators used is preferably 0.001 to 2% by weight based on the monomers used.

In the contact lens of the present invention, these monomers are injected into a glass tube, a tube made of polypropylene or polytetrafluoroethylene, or a sheet-like void and heated to cause thermal polymerization, or ultraviolet rays are applied. Irradiation and photopolymerization are suitable. Also,
After that, when distortion occurs in the polymer due to polymerization shrinkage or polymerization heat, it is desirable to perform heat annealing in order to eliminate the distortion. The contact lens thus formed is appropriately swelled by immersing it in physiological saline or the like.

[0024]

The contact lens according to the present invention copolymerizes N- (2-methacryloyloxyethyl) -2-pyrrolidone, an alkyl (meth) acrylate and a fluoroalkyl (meth) acrylate having excellent copolymerizability with various monomers. It has excellent optical performance,
It has sufficient mechanical strength so that it is not easily damaged by handling the lens such as washing. Further, since it contains a fluoroalkyl (meth) acrylate, it is possible to impart a shape stability and a property of being less likely to be contaminated.
In the present invention, a composition that exhibits these advantages is found.

[0025]

[Examples] The present invention will be described in more detail with reference to the following examples.
The present invention is not limited to these. In addition, a part represents a weight part in an Example.

(Example 1) N- (2-methacryloyloxyethyl) -2-pyrrolidone 60 parts by weight, methyl methacrylate 20 parts by weight, 2,2,2-trifluoroethyl methacrylate 19 parts by weight, trimethylolpropane trimethacrylate 1 part by weight and 0.1 part by weight of azobis (2,4-dimethylvaleronitrile) were mixed well, and this mixture was placed in a glass sealed tube, the inside was replaced with nitrogen and deaeration was repeated, and the mixture was sealed under vacuum. This sealed tube is heated in warm water at 30 ℃
10 hours, 40 ° C for 5 hours, 50 ° C for 5 hours, 60 ° C
For 3 hours and 70 ° C for 3 hours, and then in an atmospheric furnace for 100 hours.
Polymerization was carried out by heating at ℃ for 2 hours to obtain a round bar. The obtained rod was cut to obtain a contact lens. This lens was swollen in pure water, washed, and then immersed in physiological saline to absorb a predetermined amount of water, and at the same time, the elution of the eluate was completed. The contact lens thus obtained has a water content of 44%, has a good wearing feeling, has excellent optical performance, and has a breaking strength of 211 g and an elongation of 1%.
At 9 mm, the mechanical strength was excellent. In addition, as a result of the evaluation of the stain resistance, it was found that the adhesion of protein was extremely small as compared with the conventional soft contact lens. The oxygen permeability is ^{25 × 10 -1 1 ml · cm} / c
It was m ² · sec · mmHg.

The evaluation method was carried out according to the following criteria. <Evaluation Criteria> (1) Oxygen Permeability Coefficient (Dk Value) Using a Scientific Instruments film oxygen permeability meter manufactured by Rika Seiki Co., Ltd., a diameter of 12. The thickness and the current value (i ∞) of the samples with the thickness of 7 mm changed were measured. Taking the obtained thickness on the x-axis and n · F · A · Pi∞ on the y-axis, a regression line y = ax + b is obtained by the method of least squares, and the reciprocal of this gradient (1 / a) is taken as [Dk value]. did. However, here
n is the number of electrons involved in the electrode reaction, F is the Faraday constant,
A is the area of the platinum electrode, and P is the atmospheric pressure.

(2) Water content As described above, after washing with pure water and replacing with physiological saline, several lenses were prepared and the total weight (a) was measured, After replacement with pure water again, the product was dried in a vacuum dryer for 72 hours, the total weight (b) of the dried lenses was obtained, and the water content was calculated by the following formula. Moisture content = (a−b) ÷ a × 100 (3) Strength: 0.1 mm in thickness and 8 m in width with water containing physiological saline.
A plate-shaped molded product of m was prepared and used as a test piece. This test piece was sandwiched between the upper and lower ends in physiological saline at 10 mm intervals,
It was stretched, and the stress at break (break strength) and the distance (elongation) between the fulcrums at that time were measured. (4) Stain resistance Contact lenses were placed in a physiological saline solution containing 0.5% by weight of egg white lysozyme, left at 60 ° C. for 2 hours, thoroughly washed with physiological saline, and then the UV absorbance at a wavelength of 280 nm was measured. Then, the adhesion amount of the obtained egg white lysozyme was determined.

(Examples 2 to 10) Examples 2 to 10 are shown in Table 1.
Shown in. Polymerization and tests were carried out in the same manner as in Example 1 with the compositions shown in Table 1.

[0030]

[Table 1]

The abbreviations of the monomers in the table are as follows. NMEP: N- (2-methacryloyloxyethyl)-
2-Pyrrolidone MMA: Methyl Methacrylate R4MA: n-Butyl Methacrylate F3MA: 2,2,2-Trifluoroethyl Methacrylate F9MA: 3,3,4,4,5,5,6,6,6-Nonafluorohexyl Methacrylate F6MA : 2,2,2-trifluoro-1-trifluoromethylethyl methacrylate GMA: 2,3-dihydroxypropyl methacrylate DMA: N, N-dimethylacrylamide SiMA: tris (trimethylsiloxy) silylpropyl methacrylate EGDMA: ethylene glycol dimethacrylate TMPTMA: trimethylolpropane trimethacrylate (Comparative Example 1) In Example 1, containing no N- (2-methacryloyloxyethyl) -2-pyrrolidone,
Instead, a contact lens was obtained in the same manner as in Example 1 except that 60 parts by weight of N-vinyl-2-pyrrolidone was used. In the same manner as in Example 1, immersion in physiological saline was performed to sufficiently absorb water, and at the same time, elution of the eluate was completed. The contact lens thus obtained had a water content of 55% and a good wearing sensation, but had insufficient mechanical strength. Moreover, as a result of the evaluation of the stain resistance, protein adhesion was slightly observed. (Comparative Example 2) The same procedure as in Example 1 was repeated except that 2,2,2-trifluoroethyl methacrylate was not contained at all and 39 parts by weight of methyl methacrylate was used instead of the contact in Example 1. Got the lens.
In the same manner as in Example 1, immersion in physiological saline was performed to sufficiently absorb water, and at the same time, elution of the eluate was completed. The contact lens thus obtained has a water content of 4
At 5%, the feeling of wearing was good, but the oxygen permeability was insufficient.

[0032]

The contact lens according to the present invention comprises N- (2-methacryloyloxyethyl) -2-pyrrolidone, an alkyl (meth) acrylate and a fluoroalkyl (meth) acrylate which have excellent copolymerizability with various monomers. In addition to having sufficient mechanical strength so as not to be easily damaged by handling the lens such as washing, it also has sufficient optical performance capable of correcting corneal astigmatism. In addition, since it is difficult for dirt to adhere and the growth of bacteria is suppressed, it can be expected that safety is high.

Claims (5)

[Claims] 1. A soft contact lens comprising the following A, B and C as essential components. A: N- (2-methacryloyloxyethyl) -2-pyrrolidone B: Alkyl (meth) having an alkyl group having 1 to 4 carbon atoms
Acrylate C: Fluoroalkyl (meth) acrylate 2. The components A, B and C are characterized in that the component A is 20 to 80 parts by weight, the component B is 5 to 40 parts by weight, and the component C is 5 to 40 parts by weight. Item 1. A soft contact lens according to item 1. 3. The soft contact lens according to claim 1, which contains less than 40% by weight of a hydrophilic monomer in addition to the essential components. 4. The hydrophilic monomer according to claim 3,
Soft contact lens according to claim 1, characterized in that it is dihydroxypropyl methacrylate. 5. The soft contact lens according to claim 1, which contains less than 5% by weight of a cross-linking agent in addition to the essential components.