JPH0115847B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a novel hydrous contact lens. [Prior Art] Various water-containing contact lenses have been known, and among them, lenses with a water content of 40% (weight %, hereinafter the same) whose main component is 2-hydroxyethyl methacrylate (hereinafter abbreviated as 2-HEMA) The one before and after is the most widespread. However, this type of water-containing contact lens does not have sufficient permeability to the corneal physiologically required amount of oxygen, so it has the disadvantage that it cannot be worn continuously for long periods of time. Wearing it in excess is not preferable as it may cause metabolic disorders of the cornea. For this reason, research has been carried out on various high water content contact lenses with the aim of increasing the water content and supplying the cornea with the amount of oxygen necessary for corneal physiology from the atmosphere through the large amount of water contained in the contact lens material. being done. The most common material for highly hydrophilic contact lenses is N-, which is a strongly hydrophilic monomer.
Vinyl-2-pyrrolidone (hereinafter abbreviated as N-VP)
It is a copolymer obtained by copolymerizing this with an alkyl ester of methacrylic acid or acrylic acid, such as methyl methacrylate (hereinafter abbreviated as MMA). High water content contact lenses made of these copolymers usually have a
It has a water-holding capacity of 80%, and generally the amount of oxygen required by the cornea can be supplied to the cornea from the atmosphere through the water contained in the lens material. However, such copolymers have N-
Due to the difference in polymerizability between the N-vinyl group of VP and the methacryloyl and acryloyl groups of the alkyl ester of methacrylic acid or acrylic acid, a polymer of N-VP and a polymer of an alkyl ester of methacrylic acid or acrylic acid They tend to undergo phase separation, which has disadvantages such as reduced transparency when hydrated and insufficient mechanical properties. Therefore, the present inventors developed N-methyl-3-methylene-2-pyrrolidone (hereinafter abbreviated as N-MMP), which has strong hydrophilicity equal to or higher than that of N-VP and has excellent polymerizability. - It has been found that the combination use with VP is extremely useful for solving the above-mentioned drawbacks, and the present invention has been completed. [Structure of the Invention] That is, the present invention provides a strong hydrophilic monomer N
The present invention provides a water-containing contact lens made of a copolymer mainly composed of -MMP and N-VP and an alkyl ester of methacrylic acid or acrylic acid, which is most suitable as a reinforcing monomer. In detail, as a hydrophilic monomer unit, the formula () N-MMP and N-VP, represented by A group having 1 to 3 carbon atoms and a group having 8 to 18 carbon atoms are used together in a weight ratio of about 1:3 to 3:1, and the hydrophilic monomer unit and the reinforcement are combined. The usage ratio of the monomer units is approximately 50:50 to 95:5 by weight.
and a water-containing contact lens made of a copolymer characterized in that the ratio of N-MMP and N-VP used is about 1:3 to 3:1 by weight. . N used as a hydrophilic monomer unit in the present invention
- Since the polymerizable group of MMP is an amide C=CH ₂ group adjacent to a carbonyl group, it is not copolymerizable even when copolymerized with an alkyl ester of methacrylic acid or acrylic acid used as a reinforcing monomer unit. Therefore, the resulting copolymer is well crosslinked; for example, even when a water-containing contact lens made of the resulting copolymer is sterilized by boiling, the uncrosslinked N-MMP polymer remains There is very little possibility that it will elute, and it is stable. N-MMP with these properties
By using N-VP in combination with the conventionally used N-VP, there is no phase separation in the copolymer or phenomena such as clouding when water is added, which have been observed in the past.
A water-containing contact lens material with excellent transparency and optical properties can be obtained, and water-containing contact lenses manufactured from this material also have excellent transparency and optical properties. The ratio of N-MMP and N-VP used is in the range of about 1:3 to 3:1 by weight, preferably in the range of about 1:2 to 2:1. N-MMP and N-
If the ratio of VP to be used is not within the above range, macroscopic polymerization of the alkyl ester of methacrylic acid or acrylic acid, which is a reinforcing monomer unit, and the polymer of N-VP, which is a hydrophilic monomer unit, will occur as described above. If phase separation occurs or if only N-MMP is used as a hydrophilic monomer unit, the rubber hardness when hydrated is low and the shape stability tends to be poor, which is not preferable. Examples of the alkyl ester of methacrylic acid or acrylic acid used as the reinforcing monomer in the present invention include esters of alkyl groups or halogen-substituted alkyl groups. In order to make the hydrous contact lens of the present invention have excellent mechanical properties, that is, hardness and strength, it is necessary to use two or more types of alkyl esters of methacrylic acid or acrylic acid with different properties. In particular, those in which the alkyl group in the alkyl ester of methacrylic acid or acrylic acid has 1 to 3 carbon atoms, and those in which the number of carbon atoms is 8
It is preferable to use 1 to 18 pieces together at a weight ratio of about 1:3 to 3:1. More preferably it is in the range of about 1:2 to 2:1. Specific examples of reinforcing monomers used in the present invention include methacrylate compounds such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, tetradecyl methacrylate, and trifluoroethyl methacrylate; Examples include acrylate compounds for The ratio of the two types of monomer units, i.e., hydrophilic monomer units N-MMP and N-VP, and reinforcing monomer units methacrylic acid or alkyl ester of acrylic acid, is approximately
In the range of 50:50 to 95:5, preferably about 60:40 to 90:10, the total amount of these two monomers used
If the amount of alkyl ester of methacrylic acid or acrylic acid used is less than 5 parts by weight per 100 parts (parts by weight, the same applies hereinafter), it is difficult to obtain a product with sufficient strength, and if it is more than 50 parts by weight. Then, N-MMP and N-MMP used in the present invention
The strong hydrophilic effect of VP is negated, resulting in a decrease in water content and eventually oxygen permeability, which is undesirable. Further, from the viewpoint of stabilizing the shape of the water-containing contact lens of the present invention and improving solvent resistance, a crosslinkable monomer having two or more polymerizable functional groups is usually used. Such crosslinking monomers include, for example, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate,
Polyethylene glycol dimethacrylates such as triethylene glycol dimethacrylate and tetraethylene glycol dimethacrylate and diacrylate compounds corresponding to these dimethacrylate compounds, polypropylene glycols such as propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, and tripropylene glycol dimethacrylate Dimethacrylate and diacrylate compounds corresponding to these dimethacrylate compounds, vinyl methacrylate, vinyl acrylate, allyl methacrylate, allyl acrylate, divinylbenzene, diallyl phthalate, trimethylolpropane trimethacrylate, glycerol dimethacrylate, glycerol diacrylate, 3-allyloxy -2-hydroxypropyl methacrylate, etc., and one or two of these
Use by mixing more than one species. The amount of the crosslinking monomer used is approximately 0.01 to 100 parts of the total amount of the hydrophilic monomer units N-MMP and N-VP and the reinforcing monomer unit methacrylic acid or alkyl ester of acrylic acid. A range of 5 parts is preferred. In the present invention, a portion of the amount of the hydrophilic monomer units used may be replaced with various hydrophilic monomers used as components of ordinary hydrous contact lenses. Examples of such hydrophilic monomers include 2-
Examples include hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, ethylene glycol monomethyl ether methacrylate, and N,N-dimethylacrylamide. The amount of these hydrophilic monomers used is the hydrophilic monomer unit N-MMP.
and approximately 0:100 in weight ratio to the total amount of N-VP.
A ratio of 20:80 to 20:80 is necessary from the viewpoint of ensuring the desired properties of the hydrous contact lens of the present invention. During polymerization, common polymerization initiators such as azobisisobutyronitrile, azobisdimethylvaleronitrile, t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, acetyl peroxide, di-t-peroxide are used. -Butyl, azodicyclohexylcarbonitrile, dimethyl azodiisobutyrate, succinic acid peroxide, etc. can be used, and the amount used is in the range of about 0.001 to 5 parts, preferably about 0.01 to 2 parts, based on 100 parts of the total polymerization monomer. It is. Further, the polymerization method may be either ordinary bulk polymerization or solution polymerization. In the case of solution polymerization, the solvent used is one that can dissolve all the monomers used in the polymerization, such as acelonitrile, N
- Preference is given to using methylpyrrolidone, dimethylsulfoxide, dimethylformamide, ethanol, methanol and the like. In addition, in the case of any polymerization method, the temperature increasing method is used, for example, about
After heating and polymerizing at 40 to 50℃ for several to several tens of hours, approx.
It is preferable to complete the polymerization by increasing the temperature at a rate of 10° C./several hours. The above polymerization can be carried out in a mold having a shape corresponding to the desired contact lens to obtain a contact lens of the desired shape, or it can be formed into a contact lens by machining such as cutting and polishing. By hydrating and swelling the molded product, the desired water-containing contact lens can be obtained. [Effects of the Invention] The thus obtained water-containing contact lens contains N-
By using MMP and N-VP together,
It is possible to maintain a high water content (approx. 55-90%) without sacrificing excellent optical properties such as transparency, and it also contributes to improving mechanical properties such as rubber hardness, resulting in shape stability. It will be an improved version. In addition, because it can achieve a high water content, it has excellent oxygen permeability and can be worn continuously on the eye for a long time. There is virtually no elution of MMP polymers, etc., making it extremely safe for eye tissues. [Examples and Comparative Examples] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Example 1 42.5 parts of N-MMP in a polypropylene test tube,
42.5 parts of N-VP, 7.5 parts of MMA, 7.5 parts of dodecyl methacrylate, 0.5 part of allyl methacrylate, and 0.1 part of azobisisobutyronitrile as a polymerization initiator were mixed and heated in a 40°C water bath for 36 hours. The polymerization was completed after 8 hours in a hot air circulation dryer at 50°C for 4 hours and then increasing the temperature by 10°C every 1.5 hours to 110°C. The polymer was then taken out from the polypropylene test tube, cured at 90°C for 2 hours, processed into blocks with a diameter of 10 mm and a thickness of 3.5 mm, and films with a diameter of 10 mm and a thickness of 0.15 mm. Physical properties were measured. The results are shown in Table 1. The physical properties were measured using the above film in the following manner. Moisture content (wt%) = Equilibrium water-containing film weight (
W) - Dry film weight (Wo) / Equilibrium water-containing film weight (W) x 100 Linear swelling rate = Equilibrium water-containing film diameter / Diameter of film before swelling Oxygen permeability coefficient (DX) (m10 ₂・cm/cm ²・sec・mm
Hg): Measured using a Seikaken film oxygen permeability meter (manufactured by Rika Seiki Kogyo Co., Ltd.). Puncture load (g): Using an Instron-type compression tester, a pressure needle with a diameter of 1/16 inch was applied to the center of the film in a water-containing state, and the weight at breakage was measured. Elongation rate (%): The elongation rate (%) at break of the film was measured when the above punching load (g) was measured. Rubber hardness (degrees): Measured according to JIS K6301. Visible light transmittance (%): Using UV240 manufactured by Shimadzu Corporation, the transmittance of visible light in the wavelength range of 780 to 380 nm was measured. Further, the block with a diameter of 10 mm and a thickness of 3.5 mm was cut and polished to form a contact lens shape, and this was swollen with physiological saline to obtain the desired hydrous contact lens. The obtained contact lens was colorless and transparent, and was satisfactory as a water-containing contact lens. Examples 2 to 16 After polymerizing a monomer mixture containing the components and amounts shown in Table 1 as in Example 1,
A film having a thickness of 0.15 mm was processed, and the physical properties of this film were measured in the same manner as in Example 1. The results are shown in Table 1.

【table】

【table】

[Table] Comparative Examples 1 to 6 Comparative examples in which only either N-MMP or N-VP was used as the hydrophilic monomer unit are shown in Table 2. Example 1
After polymerizing in the same manner as above, the diameter is 10 mm and the thickness is 0.15 mm.
It was processed into a mm film and various physical properties were measured. The results are shown in Table 2. Examples 1, 4, 7, 10, 13 and Comparative Examples 1, 2,
Comparing No. 3 and No. 5, we found that the combined use of N-MMP and N-VP as hydrophilic monomer units resulted in excellent physical properties such as optical properties, high water content, and high oxygen permeability. While maintaining the same, the punching load (g) and rubber hardness (degrees) were improved by several steps, which can be said to indicate improved durability and shape stability as a hydrous contact lens.

【table】

Claims (1)

[Claims] 1 As a hydrophilic monomer unit, the formula () A copolymer containing N-methyl-3-methylene-2-pyrrolidone and N-vinyl-2-pyrrolidone represented by the above, and an alkyl ester of methacrylic acid or acrylic acid as a reinforcing monomer unit, The alkyl ester of methacrylic acid or acrylic acid is used in a weight ratio of about 1:3 to 3:1 of the alkyl group having 1 to 3 carbon atoms and the alkyl group having 8 to 18 carbon atoms. and the ratio of the hydrophilic monomer unit and the reinforcing monomer unit is about 50:50 to 50:50 by weight.
95:5, and the ratio of the N-methyl-3-methylene-2-pyrrolidone to N-vinyl-2-pyrrolidone is about 1:3 to 3:1 by weight. A water-containing contact lens made of copolymer.