JPS63293520A - Hydrous soft contact lens - Google Patents

Abstract

PURPOSE:To decrease the degradation in mechanical strength and adhesion of stains by copolymerizing a specific compsn. and molding the copolymer, thereby enhancing the oxygen permeability of a lens and suppressing an increase in the moisture content thereof. CONSTITUTION:The titled lens is molded of the copolymer of the compsn. essentially consisting of 30-50wt.% dimethylacrylamide and 30-50wt.% fluoroalkyl (meth)acrylate (A). The above-mentioned component A is preferably selected from trifluoroethyl-, tetrafluoropropyl- and hexafluoroisopropyl (meth)acrylates. 10-20wt.% ethyl methacrylate and 0.1-10wt.% crosslinking agent (e.g.: ethylene glycol dimethacrylate) are preferably incorporated further into the above- mentioned compsn.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydrous soft contact lens, and more specifically, a hydrous soft contact lens that has high oxygen permeability independent of water content and has low contamination caused by protein sticking. Regarding soft contact lenses.

[Prior art] Contact lenses are broadly classified into hard contact lenses and soft contact lenses. Generally, hard contact lenses are optically superior, but because of their low oxygen permeability, they cannot be worn for long periods of time, and they also damage the cornea. Due to the lack of familiarity with contact lenses, they have drawbacks such as causing lachrymation and a foreign body sensation, and in recent years soft contact lenses have become widely used in place of these lenses. For soft contact lenses, hydrophilic 2-droxyethyl methacrylate (
It is known that the main component is a polymer (hereinafter referred to as HEMA), and its water content ranges from 20% by weight to 80% by weight.
and covers a wide range. Typical lenses of this type are those made by copolymerizing HEMA with N-vinylpyrrolidone and those made by copolymerizing HEMA with methacrylic acid. Soft contact lenses have oxygen permeability due to the water in their gel.
There is a nearly linear proportional relationship between oxygen permeability and water content. Therefore, in the past, in order to enable long-term continuous wear, the water content of the hydrogel was increased to improve oxygen permeability, or the lens was made extremely thin to increase the amount of oxygen permeation per unit area per unit time. There were two methods taken.

[Problems to be Solved by the Invention] However, in the method of increasing oxygen permeability by increasing the water content, the mechanical strength of the lens material weakens as the water content increases, and the variation in swelling ratio increases. Disadvantages include that it becomes difficult to obtain stable vision, and that dirt seeps into the lens, making it difficult to clean and remove.

In addition, with the method of making the lens thinner and increasing the amount of oxygen permeation, the lens may adhere along the pad of the finger when worn, or
The drawback is that the lenses roll up, making them extremely inconvenient to wear.

Therefore, a lens material that has oxygen permeability higher than expected for its water content is desired, and the present invention has sufficient oxygen permeability without increasing the water content too much, and has excellent mechanical strength and stain resistance. The object is to provide a soft contact lens with high oxygen permeability that is improved in terms of adhesion.

[Means for solving the problems] The present invention provides 30 to 50% by weight of dimethylacrylamide,
A water-containing soft contact lens characterized by being molded by copolymerizing a composition containing 30 to 50% by weight of fluoroalkyl acrylate or fluoroalkyl methacrylate as a main component.

Dimethylacrylamide is not preferable if it is less than 30% by weight because it reduces flexibility when it contains water (if it exceeds 50% by weight, the strength decreases and the water content becomes too high, resulting in unstable vision and problems with attached dirt. This is not preferable because it has drawbacks such as being difficult to remove.

If fluoroalkyl acrylate or fluoroalkyl methacrylate is less than 30% by weight, the effect of improving oxygen permeability is low, and the effect of preventing dirt from sticking is low;
If it exceeds 0% by weight, it is not preferable because it tends to cause staining due to lipids. The fluoroalkyl (meth)acrylate preferably comprises an alcohol having a fluoroalkyl group, particularly a perfluoroalkyl group, in which the hydrogen atoms of an alkyl group having 2 to 10 carbon atoms are partially substituted with fluorine atoms, and (meth)acrylic acid. In the ester, the alkyl group may be annular or may have a side chain.

Typically trifluoroethyl (meth)acrylate,
Tetrafluoropropyl (meth)acrylate, hexafluoroisopropyl (meth)acrylate1. Octafluoropentyl (meth)acrylate and tetrahydrohexadecafluorodecyl (meth)acrylate are mentioned, but other fluoroalkyl (meth)acrylates can also be used.

In the present invention, in addition to the above dimethylacrylamide and fluoroalkyl (meth)acrylate, methyl methacrylate can be added, preferably in an amount of 10 to 20%. This is for the purpose of improving strength, and if it is less than 10% by weight, this effect will be low, and if it exceeds 20% by weight, the effects of dimethylacrylamide and fluoroalkyl (meth)acrylate will be relatively low, which is not preferable.

Further, for the purpose of improving cutting and polishing properties, dimensional stability during hydration swelling, etc., a crosslinking agent may be preferably added in an amount of 0.1 to 10% by weight. The crosslinking agent is selected from at least one of the polyfunctional I11 groups, typically ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene. Glycol diacrylate, allyl methacrylate, allyl acrylate, vinyl methacrylate, diallyl succinate,
Examples include divinyl succinate, trimethylolpropane trimethacrylate, diallyl phthalate, divinylbenzene, pentaerythritol tetramethacrylate, triallyl isocyanurate, and the like.

The water-containing soft contact lens of the present invention is produced by adding a conventional radical polymerization initiator to the above composition, mixing with stirring, placing the mixture in a mold, and polymerizing it generally at a temperature in the range of 40°C to 100°C. After cooling, cutting and polishing are performed to form a lens shape with desired dimensions. This is immersed in physiological saline to hydrate and swell.

The hydrous soft contact lenses of the invention thus obtained have a higher oxygen permeability than would be expected at a given water content, and therefore have sufficient oxygen permeability even if the water content is not too high. As a result, it is possible to improve the problems of mechanical strength reduction and dirt adhesion caused by high water content, and the lens becomes less likely to attract dirt even when the water content is the same.

[Example] Monomers having the compositions shown in Table 1 were mixed and stirred, placed in a polypropylene test tube, and polymerized by being held in an aqueous solution at 60°C for 48 hours and then in an air atmosphere at 90°C for 72 hours.

After cooling, the rod-shaped polymer was extracted from the test tube and processed into a contact lens shape by a known cutting and polishing method.
Hydration swelling was achieved by immersion in physiological saline at 0° C. for 16 hours.

Table 1 shows the physical properties of each lens obtained. The oxygen permeability and water/octane contact angle were determined by forming a disk with a diameter of 11.4 nn and a thickness of 0.17 m in the same manner as above.
Measurements were made using this disk.

The oxygen permeability coefficient was measured at 37° C. using a Seikaken film oxygen permeability meter. In general water-containing soft contact lenses, oxygen permeability depends on the amount of water in the hydrogel, so the oxygen permeability coefficient and water content are linearly proportional, as shown in the standard straight line shown in the graph of the attached drawing. However, in the lenses obtained in Examples 1 to 4 according to the present invention, the relationships between oxygen permeability coefficient and water content are all above this straight line, which is expected at a constant water content for this type of hydrogel. It can be seen that the oxygen permeability is significantly higher than that of the

The water/octane contact angle is calculated by leaving a sample hydrated in pure water at a temperature of 25°C and bringing an n-octane oil droplet into contact with the bottom surface of the sample, and then calculating the angle formed between the sample surface and the oil droplet. It was measured using a contact angle meter manufactured by Kyowa Scientific Co., Ltd. This contact angle is a measure of the strength of the interaction between a sample and a protein, and there is a proportional relationship between the size of the angle and the surface energy of the resin.Therefore, the larger this angle is, the more likely it is that protein stains will occur.According to the present invention The samples obtained in Examples 1 to 4 all have smaller water/octane contact angles than the samples of Comparative Examples, and are resistant to sticking of protein stains.

[Brief explanation of the drawing]

The accompanying drawing is a graph showing the relationship between water content and oxygen permeability coefficient in a hydrous soft contact lens. Patent applicant: Seed Kaichu Co., Ltd. ('7o)

Claims (5)

[Claims] (1) A hydrous soft contact lens characterized by being molded by copolymerizing a composition whose main components are 30 to 50% by weight of dimethylacrylamide and 30 to 50% by weight of fluoroalkyl acrylate or fluoroalkyl methacrylate. (2) Fluoroalkyl acrylate or fluoroalkyl methacrylate is trifluoroethyl (meth)
acrylate, tetrafluoropropyl (meth)acrylate, hexafluoroisopropyl (meth)acrylate, octafluoropentyl (meth)acrylate,
The water-containing soft contact lens according to claim (1), which is at least one compound selected from the group consisting of tetrahydrohexadecafluorodecyl (meth)acrylate. (3) The hydrous soft contact lens according to claim (1) or (2), wherein the composition further contains 10 to 20% by weight of methyl methacrylate. (4) The hydrous soft contact lens according to any one of claims (1) to (3), wherein the composition further contains 0.1 to 10% by weight of a crosslinking agent. (5) The crosslinking agent is ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, allyl methacrylate, allyl acrylate, vinyl methacrylate, diallyl succinate. , divinyl succinate, trimethylolpropane trimethacrylate, diallyl phthalate, divinylbenzene, pentaerythritol tetramethacrylate, and triallyl isocyanurate. The water-containing soft contact lens according to item (4).