JPS6294819A - Contact lens - Google Patents

Abstract

PURPOSE:To provide a contact lens capable of supplying O2 during closing of eyes, having softness and hydrophilic property and sufficient compatibility to eye, and to permit continuous use for a long time by graft polymerizing hydrophilic polymer chains with the surface of a polymer lens consisting principally of poly(trialkylvinylsilane). CONSTITUTION:The surface of a hydrophobic lens consisting principally of poly(trialkylvinylsilane) is irradiated with low temp. gas plasma, then the treated lens is taken out to bring into atmosphere; thus, peroxides are formed on the surface. Then, the lens is immersed in a solution of a kind of hydrophilic monomer or a mixture of several kinds of hydrophilic monomers, and hydrophilic graft chains are introduced to the surface of the lens by redox polymn. or thermal polymn. The contact lens prepd. by this process can keep the hydrophilic property permanently even if it is allowed to stand in the air. Further, the antifouling property is also improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contact lens made by making the surface of a lens base material mainly made of hydrophobic poly(trialkylvinylsilane) hydrophilic.

More specifically, the present invention relates to a contact lens made hydrophilic by forming hydrophilic graft chains on the surface of a lens mainly made of poly(trialkylvinylsilane).

Poly(trialkylvinylsilanes) have oxygen permeability,
It has attracted attention as a material for contact lenses because of its excellent transparency, chemical stability, and thermal stability. However, when worn as a contact lens, the hydrophobicity is a problem and the performance as a contact lens cannot be fully expressed.

The present inventors have created a lens using poly(trialkylvinylsilane) as its main material, imparted hydrophilic properties to the lens, and improved its suitability for wearing.The present inventors have created a lens that is extremely practical and satisfies almost all of the physical properties required for contact lenses. He invented contact lenses.

In general, the requirements for contact lenses are that they do not interfere with the metabolic function of the cornea, that they have good vision correction ability and good transparency, that they do not scratch the cornea, and that they do not stain easily with components in tear fluid. The design of the contact lens is optimal, allowing it to move easily over the cornea, the material is not adhering to the cornea, and it is easy to handle and difficult to break.

Currently, contact lenses are broadly classified into two types: hard contact lenses, which are smaller than the corneal diameter and made of a hard material, and soft contact lenses, which are larger than the corneal diameter and made of a soft material. It doesn't satisfy everything. For example, hard contact lenses made of poly(methyl methacrylate) are known, and they have excellent vision correction ability and are relatively easy to handle, making them the mainstream contact lens.
Because it is hard and hydrophobic, it has poor affinity with the eyes.
It has the disadvantage that it feels like a foreign body when wearing it, and it also has the disadvantage that it feels like a foreign body when worn.
Methyl methacrylate) has extremely low oxygen permeability, so (0,005xl ○-9cm3(STP)CIIl
/cI112・sec-clIIHg) It inhibits oxygen respiration of the cornea, which is an avascular tissue, and limits the wearing time.

In order to improve the oxygen permeability of poly(methyl methacrylate), copolymers with various silicone compounds are known (Japanese Unexamined Patent Publication No. 50-87184, No. 54-5545).
5) The oxygen permeability is insufficient to supply all the oxygen necessary to the cornea through the contact lens, which is still a problem.

On the other hand, soft contact lenses have been developed with improved wearing comfort and oxygen permeability, and are mainly made of hydrogel type mokuno made from poly(2-hydroxyethyl methacrylate), silicone rubber, and butyl rubber. There is a water-free elastic material that can be swallowed. Poly(2-hydroxyethyl methacrylate) contact lenses are flexible hydrogel contact lenses that are compatible with eye tissue and have the advantage of less foreign body sensation when worn. However, since it is a hydrous gel, it lacks dimensional stability and mechanical strength, has poor vision correcting ability, is easily damaged, and is troublesome to handle, such as when disinfecting contact lenses.
There are problems with lachrymal stains and drug uptake in the washing solution, and the oxygen permeability is not necessarily sufficient for the cornea's needs.

Silicone rubber contact lenses have high oxygen permeability, but because they are elastic, they are difficult to precisely process, and they also have the disadvantage that components in tear fluid accumulate inside the contact lenses.

In addition, butyl rubber contact lenses do not necessarily have sufficient oxygen permeability to meet the needs of the cornea, and because they are elastic, it is difficult to process them precisely, and components of tear fluid may deposit inside the contact lens. There are drawbacks.

In view of the above, the present inventors believe that the ultimate goal of contact lenses is long-term continuous wear, and we have developed poly(trialkylvinylsilane) as a contact lens base material that has oxygen permeability sufficient to supply sufficient oxygen to the cornea even when the eyes are open. )
Focusing on polymers, we believed that if they were made to be more flexible, hydrophilic, and highly compatible with the eyes, they would become ideal contact lenses, and as a result of intensive research, we finally arrived at the present invention.

In the present invention, first, a polymer containing poly(trialkylvinylsilane) as a main component is mainly used as a raw material monomer, and n-butylvinylsilane is used as a raw material monomer.
It is obtained by adding an anionic polymerization initiator such as lithium and performing anionic polymerization in an inert gas atmosphere. Examples of the alkyl group here include methyl, ethyl, propyl, butyl, and isobutyl groups. These alkyl groups may be the same or two or more different groups, but are preferably methyl groups. It is also possible to use mixtures of trimethylvinylsilane and other trialkylvinylsilanes.

Next, a lens having an arbitrary shape can be obtained by molding the polymer containing poly(trialkylvinylsilane) as a main component into a desired shape by a known method and subjecting it to machining.

Lens materials used in the present invention include poly(trialkylvinylsilane) alone, block copolymers of poly(trialkylvinylsilane) and polystyrene, polysiloxane, or polyethylene oxide, and poly(trialkylvinylsilane) as a material. vinyl silane) and poly(
Methyl methacrylate) or a blend with poly(2-hydroxyethyl methacrylate-siloxanyl methacrylate) copolymer and the like.

However, if left as is, the surface is hydrophobic and has poor affinity with the eye, giving a strong foreign body sensation.

The surface of the hydrophobic lens made of poly(trialkylvinylsilane) as a main material was treated with low-temperature gas plasma using a known method (Japanese Unexamined Patent Publication No. 53-27436), and a depth of several microns from the surface was treated. It is also possible to impart hydrophilic properties to the layer.

As mentioned above, the surface of a lens made mainly of poly(trialkylvinylsilane) treated with low-temperature gas plasma becomes hydrophilic, and its wettability with water is improved.

Generally, the degree of hydrophilicity is expressed by the contact angle between a sample and a water droplet.

The contact angle of a lens made of poly(trialkylvinylsilane) decreases from 113° before hydrophilic treatment to 20 to 35° immediately after hydrophilic treatment by low-temperature gas plasma treatment, resulting in significantly improved wettability.

However, if the material is left to dry in the air after the low-temperature gas plasma treatment, the contact angle increases and gradually becomes hydrophobic, eventually reaching 113°, which is exactly the same value as before the hydrophilic treatment.

In this way, the lens surface, which is mainly made of poly(trialkylvinylsilane), will improve its wettability immediately after simply undergoing low-temperature gas plasma treatment, but if it is left to dry in the air, it will gradually deteriorate. hydrophilicity is lost.

Therefore, in order to permanently maintain hydrophilicity even when left in the air, in the present invention, the lens surface mainly made of poly(trialkylvinylsilane) is made hydrophilic by plasma graft polymerization or photograft polymerization. Introducing polymer graft chains.

After generating a peroxide bond that can be graft-polymerized, a water-soluble monomer is graft-polymerized to form a peroxide group by an addition reaction with atmospheric oxygen, and then the water-soluble monomer is subjected to radical graft polymerization. It is. However, γ-ray and electron beam irradiation have a pretreatment effect on the bulk layer deeper than the surface layer, and the oxygen permeability decreases significantly due to crosslinking reactions, etc., and is not suitable for application to contact lenses. That is, the above-described plasma graft polymerization or photograft polymerization is a very effective method for imparting functionality.

In the present invention, first, the surface of a hydrophobic lens mainly made of poly(trialkylvinylsilane) is irradiated with low-temperature gas plasma, which has an initial effect only on a layer several microns deep from the surface. It is taken out into the air and peroxide groups are introduced onto the surface. Here, as the gas, argon gas, helium gas, nitrogen gas, oxygen gas, ammonia gas, etc., or a mixed gas thereof is used. In the present invention, glow discharge treatment is performed at a system gas pressure of 0.2 to 20 m+aHg or a system gas pressure of 150 mml (g
The plasma condition of the corona discharge treatment is ~atmospheric pressure, and the treatment time is 5 seconds to 20 minutes, preferably 15 seconds to 5 minutes.

Examples of monomers that can be suitably used herein and polymerized into hydrophilic graft chains include methacrylic acid, acrylic acid,
n-vinylpyrrolidone, acrylamide, etc. and 2-
Hydroxyalkyl methacrylates and hydroxyalkyl methacrylates, such as hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate and the corresponding acrylic esters, diethylene glycol monomethacrylate, triethylene glycol monomethacrylate, tetraethylene glycol monomethacrylate, pro- and lengelicol mono Olefin glycol monomethacrylates and corresponding acrylic esters such as methacrylate and decaethylene glycol monomethacrylate and methoxyethylene glycol methacrylate, methoxytriethylene glycol methacrylate, methoxytetraethylene glycol methacrylate, methoxypropylene glycol methacrylate and methoxypolyethylene glycol methacrylate Methoxyolefin glycol methacrylate and the corresponding acrylic ester, 2-dimethylaminoethyl methacrylate, piperidinoethyl methacrylate, and 2-butylaminoalkyl methacrylate can be used in plasma graft polymerization. i.e. poly(trialkylvinylsilane)
The lens, which is mainly made of Through polymerization, hydrophilic graft chains are introduced onto the surface of a poly(trialkylvinylsilane)-based lens.

In the present invention, another method for introducing hydrophilic graft chains onto the surface of a poly(trialkylvinylsilane)-based lens is photograft polymerization, i.e., a suitable photointensifier such as benzophenone, anthraquinone or benzoyl peroxide. In the presence of a sensitizing agent, under irradiation with light from a high-pressure or low-pressure mercury lamp, etc., the hydrophilic monomer 1 was formed into a lens mainly composed of poly(trialkylvinylsilane).
Hydrophilic graft chains are introduced onto the poly(trialkylvinylsilane)-based contact lens surface by irradiation with the seed or several vapors or solutions.

Unlike contact lenses that have simply been subjected to low-temperature gas plasma treatment, the contact lenses obtained in this way can maintain their hydrophilic properties almost permanently even when left in the air.

Furthermore, surprisingly, the present invention was further developed by discovering that stain resistance can also be improved by introducing such hydrophilic graft chains.

The present invention will be explained below with reference to Examples.

[Example 1] 0.1 g of a 15% n-butyllithium hexane solution was added to 50 g of purified trimethylvinylsilane, and anionic polymerization was performed at 60'C in an anhydrous atmosphere in nitrogen for 24 hours, followed by polymerization with a cyclohexane-methanol system. Reprecipitation purification was performed to obtain 45 g of poly(trimethylvinylsilane). 5
A wt% cyclohexane solution was poured into a mold, and a colorless and transparent film was obtained by solvent evaporation. This film was roughly cut and polished to create a lens.

Next, this lens was placed in a plasma tube, and while helium gas was passed through it, helium plasma was generated with an applied power of 128 Watts at 0.6 Torr, and glow discharge treatment was performed for 20 seconds.

After taking it out into the air and generating peroxide on the surface,
Hydrophilic graft chains were introduced onto the lens surface by immersion in a vinylpyrrolidone monomer solution and thermal polymerization at 80'C for 8 hours. Contact lenses treated in this way were well wetted with water. The contact angle of a similarly treated film is
The hydrophilicity was 40°, which was dramatically improved compared to 113° before treatment, and this hydrophilicity hardly changed over time.

In addition, when measuring the ATR-IR spectrum, it is 1600 to 1
An absorption band of carbonyl groups derived from poly-n vinylpyrrolidone was confirmed at 700 cm''.

In addition, when an aqueous solution of bovine serum albumin 50 mg/d 1 was prepared and the film was immersed for 1 hour and the ATR-IR spectrum was measured, 1 derived from amide 1 of bovine serum albumin was found.
Almost no absorption band at 655 cm" was observed, and the contact lens made of such a material had excellent stain resistance.

[Example 2] A lens obtained in the same manner as in Example 1 was placed in a plasma tube,
Corona discharge treatment was performed for 20 seconds by generating argon plasma at normal pressure while passing argon gas. ff1n vinylpyrrolidone monomer, methoxypolyethylene glycol (Mw
= 2080) Hydrophilic graft chains were introduced onto the lens surface by immersion in a solution of monoffi 3/1 (weight ratio) and thermal polymerization for 18 hours at 80'C. Contact lenses treated in this way were well wetted with water. Further, the contact angle of a film treated in the same manner was 500 and hardly changed over time.

In addition, when an aqueous solution of bovine serum albumin 50 mg/di was prepared and the film was immersed for 1 hour and the ATR-IR spectrum was measured, 16 derived from amide 1 of bovine serum albumin was detected.
Almost no absorption band at 55 cm" was observed, and the contact lens made of such a material had excellent stain resistance.

[Example 3] After benzoyl peroxide was immobilized on a lens obtained in the same manner as in Example 1, the lens was placed in a quartz glass tube.
5x in the presence of n-vinylpyrrolidone monomer in a high-pressure mercury lamp
Light was irradiated at 10-2 mmHg, 60'C, for 1 hour. Contact lenses treated in this way were well wetted with water. The contact angle of a similarly treated film was 4
00 and hardly changed over time.

Also, when measuring the ATR-IR spectrum, it is 1600 ~
An absorption band of carbonyl group originating from poly-n vinylpyrrolidone was confirmed at 1700 cm-'.

In addition, when an aqueous solution of bovine serum albumin 50 mg/dl was prepared and the film was immersed for 1 hour and the ATR-IR spectrum was measured, 16 derived from amide 1 of bovine serum albumin was detected.
Almost no absorption band at 55 cm-' was observed, and a contact lens made of such a material had excellent stain resistance.

(Margin below)

Claims (4)

[Claims] (1) A contact lens characterized in that a hydrophilic polymer chain is graft-polymerized on the surface of a polymer lens mainly composed of poly(trialkylvinylsilane). (2) The contact lens according to claim (1), wherein the alkyl group is a methyl group. (3) A contact lens according to claims (1) and (2), wherein the graft polymerization is plasma graft polymerization. (4) A contact lens according to claims (1) and (2), wherein the graft polymerization is photograft polymerization.