JPH0627910B2 - Contact lens material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a contact lens material.

[Conventional technology and its problems]

In recent years, highly oxygen permeable contact lenses that supply oxygen required for metabolism of corneal tissue from the atmosphere to the cornea through the lens material have been highlighted. As such a contact lens, for example, an oxygen-permeable hard contact lens made of a polymer essentially consisting of styrene containing silicon as disclosed in JP-A-60-142324 has been proposed. . In the publication, the siloxane moiety further bonded to styrene is a branched chain,
It is disclosed that it is preferable to the linear one in terms of rigidity.

However, when the siloxane moiety is branched, for example, those in which a silicon atom at the branch point is directly bonded to styrene, such as bis (trimethylsiloxy) methylsilylstyrene or tris (trimethylsiloxy) silylstyrene), In general, the glass transition temperature (Tg) tends to be higher than that of a linear siloxane moiety having the same number of silicon atoms, which lowers the oxygen permeability of the obtained material or makes the material brittle. The problem is that it tends to give In addition, there is no material such as silicon-containing styrene that satisfies the oxygen permeability yet. For example, in the case of a contact lens, the oxygen permeability is not sufficient for continuous wear over a long period of time. Not enough.

[Problems to be solved by the invention]

Therefore, the present inventors have arrived at the present invention as a result of earnest studies to obtain a contact lens material having excellent oxygen permeability in view of the above-mentioned problems of the conventional art.

[Means for solving problems]

That is, the present invention has the general formula (I): The present invention relates to a contact lens material comprising a styrene derivative represented by the formula (wherein R represents a methyl group, X represents a methyl group or a trimethylsilyloxyl group) and a polymer obtained by polymerizing a comonomer copolymerizable with the styrene derivative.

[Operation and Example]

The contact lens material of the present invention has the general formula (I): (In the formula, R represents a methyl group, X represents a methyl group or a trimethylsilyloxyl group), and a polymer obtained by polymerizing a comonomer copolymerizable with the styrene derivative.

The styrene derivative represented by the general formula (I) used in the present invention has a branched siloxane portion, but since the silicon atom at the branch point (branch center) is not directly bonded to styrene, for example, Since the free movement of the silicon-containing part ahead of the branch point is easier than that in the case where the silicon atom of the branch point such as bis (trimethylsiloxy) methylsilylstyrene or tris (trimethylsiloxy) silylstyrene) is directly bonded to styrene. The glass transition point (Tg) of the obtained polymer can be made relatively low.

Therefore, the obtained polymer has excellent oxygen permeability and can reduce brittleness.

Further, according to the present invention, it is possible to obtain a material which is transparent and has a relatively high refractive index due to the presence of aromatic rings in the material. In general, when used as a contact lens material, a material having a high refractive index is desirable in order to reduce the thickness of the lens to improve the wearing comfort and reduce the weight. As long as the material has a high refractive index, even a lens that gives the same power (power) can be made thin, and the contact lens material of the present invention is advantageous in this respect.

Examples of the compound represented by the general formula (I) include pentamethyl-3,3-bis (trimethylsiloxy) trisiloxanylstyrene and hexamethyl-3-trimethylsiloxytrisiloxanylstyrene, which are used alone. Alternatively, they may be mixed and used.

Next, a method for producing p- [pentamethyl-3,3-bis (trimethylsiloxy) trisiloxanyl] styrene will be described as an example of the pentamethyl-3,3-bis (trimethylsiloxy-trisiloxanylstyrene).

That is, p-chlorostyrene is converted into Grignard and then reacted with dimethyldichlorosilane to obtain p-dimethylchlorosilylstyrene. The p-dimethylchlorosilylstyrene obtained next is hydrolyzed with an aqueous sodium bicarbonate solution or aqueous ammonia to obtain p-vinylphenyldimethylsilanol. On the other hand, trichlorosilane is reacted with lithium trimethylsilanoate to form tris (trimethylsiloxy) silane. Then, chlorine gas is blown into the obtained tris (trimethylsiloxy) silane to obtain tris (trimethylsiloxy) cyclolosilane. The p- [pentamethyl-3,3-bis (trimethylsiloxy) trisiloxanyl] styrene is obtained by reacting the p-vinylphenyldimethylsilanol obtained above with tris (trimethylsiloxy) chlorosilane.

Next, as an example of the above-mentioned hexamethyl-3-trimethylsiloxytrisiloxanylstyrene, p- [hexamethyl-3-
A method for producing trimethylsiloxytrisiloxanyl] styrene will be described.

That is, chlorine gas is blown into bis (trimethylsiloxy) methylsilane to obtain bis (trimethylsiloxy) methylchlorosilane. Next, the p- [pentamethyl-3,
3-bis (trimethylsiloxy) trisiloxanyl] styrene was produced by reacting the p-vinylphenyldimethylsilanol obtained with the bis (trimethylsiloxy) methylchlorosilane with p- [hexamethyl-3-trimethylsiloxytriol]. Siloxanyl] styrene is obtained.

The styrene derivative used in the present invention uses a comonomer copolymerizable with the styrene derivative, and is copolymerized in consideration of polymerizability, film-forming property and other moldability. Specific examples of the comonomer copolymerizable with the styrene derivative include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth). Linear, branched or cyclic alkyl (meth) acrylates such as acrylates; styrene or styrene derivatives such as pentafluorostyrene, methylstyrene, trimethylsilylstyrene, trifluoromethylstyrene, dimethylaminostyrene; benzyl (meth) acrylates Aromatic ring-containing (meth) acrylates; optionally substituted alkyl esters such as itaconic acid, crotonic acid or maleic acid; glycidyl (meth) acrylate; tetrahydrofurfuryl (meth Acrylate; trifluoroethyl (meth) acrylate, fluoroalkyl such as hexafluoroisopropyl (meth) acrylate (meth)
Acrylate; Silicon-containing (meth) acrylate such as tris (trimethylsiloxy) silylpropyl (meth) acrylate, pentamethyldisiloxanylmethyl (meth) acrylate, bis (trimethylsiloxy) silylpropylglycerol (meth) acrylate; Hydroxyethyl ( (Meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, dihydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate and other hydroxyl group-containing (meth) acrylates; methoxyethyl (meth) acrylate, methoxydiethylene glycol mono Alkoxy group-containing (meth) acrylate such as (meth) acrylate; (meth) acrylic acid; (meth) acrylamide, dimethyl (Meth) acrylamides such as (meth) acrylamide; aminoalkyl (meth) acrylates such as aminoethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate; N-vinylpyrrolidone, α-methylene-N-methylpyrrolidone Vinyl lactams; vinyl pyridine, vinyl imidazole and the like, and it is preferable to use one or more selected from these. The amount used is about 0 to 80 parts by weight, more preferably 10 to 70 parts by weight, based on 100 parts by weight of the total monomer mixture. If the amount of these comonomers used exceeds the above range, the effect of using the styrene derivative represented by the general formula (I) will be diminished.

In addition, in order to impart appropriate strength to the obtained material such as alkyl (meth) acrylate and styrene to improve durability, the silicon-containing monomer appropriately improves or maintains the oxygen permeability of the material. In addition, in order to appropriately improve or maintain the chemical resistance, stain resistance, strength, oxygen permeability and the like of the fluorine-containing monomer, the styrene derivative and the aromatic ring-containing monomer improve the refractive index. In addition, the hydroxyl group-containing or alkoxy group-containing monomer, (meth) acrylic acid, (meth) acrylamides, aminoalkyl (meth) acrylates, vinyl lactams, vinyl pyridine, vinyl imidazole, etc. are used as contact lens materials. It is preferably used for imparting hydrophilicity.

Further, in order to form the obtained contact lens material into a contact lens, it is preferable to use a crosslinking agent during the polymerization. However, a cross-linking agent is not always necessary if only film formation is performed. Specific examples of such a cross-linking agent include ethylene glycol (meth) acrylate, diethylene glycol di (meth) acrylate, allyl (meth) acrylate, and trimethylolpropane tri (meth) acrylate. It is preferable to select and use two or more kinds. The amount used is about 0 in 100 parts by weight of the total monomer mixture.
-20 parts by weight, more preferably about 1-10 parts by weight. If the crosslinking agent is used in a large amount exceeding the above range, the obtained material becomes brittle and cannot be used.

The method for polymerizing the monomer or the mixture of monomers as described above can be easily performed by a method commonly used in the art. For example, it can be carried out by using a radical polymerization initiator and heating to a temperature of room temperature to about 130 ° C. or irradiation with radiation. In the case of heat polymerization, the temperature may be raised stepwise. The polymerization may be a bulk polymerization method or various methods such as a solution polymerization method using a solvent.

Specific examples of the radical polymerization initiator that can be used include, for example, azobisisobutyronitrile, azobisdimethylvaleronitrile, benzoylperoxide, etc., and one or more of them can be selected and used. To do. It is suitable to use it in an amount of 0.011 to 1 part by weight based on 100 parts by weight of all the monomers or monomer mixture used for the polymerization.

If no crosslinker is used, the molecular weight of the resulting polymer is
50,000-5,000,000, more preferably 100,000-1,000,
It is 000. If the molecular weight is smaller than the above range, it will be difficult to form a film described later, or even if it is moldable, the (mechanical) strength will be small. On the other hand, if the molecular weight exceeds the above range, molding becomes difficult or the molding method is limited, which is not preferable.

In the case of molding a contact lens, a molding method commonly used by those skilled in the art can be adopted. For example, the polymerization may be carried out in a suitable mold or container to form blocks, plates,
After obtaining a rod-shaped material, machine it into a desired shape by machining such as cutting or polishing, or prepare a mold corresponding to the desired shape, perform polymerization directly in this mold and mold it as necessary. It may be subjected to finishing processing according to need.

In addition, in the case of simply forming a film, a method usually practiced by those skilled in the art can be adopted. As an example, the uncrosslinked polymer is dissolved in a suitable solvent, the solution is spread on a suitable substrate such as a glass plate, and then the solvent is evaporated to dryness, and the resulting film is peeled from the substrate. A film can be easily formed.

In addition, a gas-permeable composite membrane can be obtained by uniformly laminating a thin film made of the material of the present invention on a porous support. As the porous support, a flat film-shaped one or a hollow fiber-shaped one can be adopted, and as the material thereof, polysulfone, cellulose acetate, nitrocellulose, ethyl cellulose, polyacrylonitrile, polypropylene,
A homopolymer such as polyvinyl chloride or a blend thereof may be employed, but the present invention is not limited to these and other ones may be used.

Specific examples of the solvent used in forming the film include chlorinated hydrocarbons such as methylene chloride, tetrachloroethane, chloroform, dichloroethane, chlorobenzene and dichlorobenzene; fluorinated carbons such as trifluoromonochloromethane and trifluoromonochloroethane. hydrogen;
Examples thereof include hydrocarbons such as benzene, toluene, xylene and cyclohexane; cyclic ether compounds such as tetrahydrofuran and dioxane, and it is preferable to use them alone or as a mixture.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1 and 2 Sufficiently purified monomers and comonomers shown in Table 1 were placed in an ampoule tube, and then tetrahydrofuran (hereinafter referred to as TH
Azobisisobutyronitrile (hereinafter referred to as AIBN) dissolved and diluted with (F) was added. The THF was prepared in a proportion of 1 ml with respect to the total monomer amount of 1 g, and the AIBN was prepared in a proportion of 0.05 to 0.1 mol% of the total monomer amount. Thereafter, the tube was degassed and sealed, and the radical polymerization reaction was carried out at 60 ° C. for 1 week.

The obtained polymer was diluted with THF and added dropwise to a large amount of methanol with stirring to cause precipitation, and the precipitate was collected. This reprecipitation operation scan was repeated several times, after which the precipitate was dissolved in benzene and freeze-dried to obtain a white polymer. The molecular weight of the obtained polymer was measured by gel permeation chromatography (hereinafter referred to as GPC).
The results are also shown in Table 1.

0.1 g of the obtained copolymer was dissolved in 4 ml of THF,
The THF solution was taken in a syringe and gently poured on a horizontally placed glass plate having a diameter of 6 cm, and then left standing at room temperature (about 20 ° C.) for 12 hours. Remove the obtained film from the glass plate, and at room temperature
After vacuum drying for 24 hours, a colorless transparent and durable film was obtained.
The thickness of the obtained film, oxygen gas permeability coefficient (hereinafter,
The separation coefficient was calculated by measuring the permeation coefficient (hereinafter referred to as PO ₂ ) and the nitrogen gas permeation coefficient (hereinafter referred to as PN ₂ ). The results are also shown in Table 1.

PO ₂ and PN ₂ were measured by a gas chromatograph method (Yanagimoto gas permeation measuring device, Model GTR-10; manufactured by Yanagimoto Manufacturing Co., Ltd. and Hitachi Gas Chromatograph K23 type; manufactured by Hitachi Manufacturing Co., Ltd.).

Comparative Example 1 In the same manner as in Examples 1 and 2, 80 parts by weight of pentamethyldisiloxanyl styrene and 20 parts by weight of styrene were copolymerized to obtain a copolymer conventionally used as an oxygen-enriched membrane material. (Yield: 65.4%). The number average molecular weight of the obtained copolymer was 18.8 × 10 ⁴ , and the weight average molecular weight was 43.2 × 10 ⁴ . Also, a film was formed in the same manner as in Examples 1 and 2, and the PO ₂ of the obtained film was 19.6 × 10 ⁻¹⁰ cc (STP) · cm / (cm ²
・ Sec ・ cmHg), PN ₂ is 5.8 × 10 ^-10 cc (STP) ・ cm / (c
m ² · sec · cmHg) and the separation factor was 3.39.

The film obtained in Comparative Example 1 had a considerably low oxygen gas permeability coefficient, which was not a satisfactory value.

Examples 3 and 4 As shown in Table 2, various components were mixed, and after thoroughly stirring, the mixture was poured into a test tube and sealed. This was placed in a constant temperature water tank, and heat-polymerized at 35 ° C for 40 hours, and then gradually heated to 130 ° C in 16 hours to heat-polymerize. The obtained rod-shaped polymer was cut and mechanically processed by cutting and polishing to obtain a colorless transparent tough contact lens.

A film having a thickness of 0.2 mm was prepared from the same material in the same manner as in Examples 1 and 2, and the oxygen permeability coefficient (hereinafter referred to as DK) was measured. The results are also shown in Table 2.

In addition, Dk was measured in 0.9% physiological saline at 35 using a Seikaken film oxygen permeability meter (manufactured by Rika Seiki Co., Ltd.). The results are shown in Table 2.

In the example of the prior document (Japanese Patent Laid-Open No. 60-142324),
Oxygen permeability coefficient (Dk) is approximately 15.0 × 10 ^{-11 to} 58.9 × 10 ^-11
It was cc (STP) · cm / (cm ² · sec · mmHg), whereas the material of the present invention was approximately 90 × 10 ^{−11 to} 150 × 10 ^−11.
It is cc (STP) · cm / (cm ² · sec · mmHg), which shows that the oxygen permeability is remarkably improved.

[Advantages of the Invention] The contact lens material of the present invention is transparent, has excellent oxygen permeability, and has a preferable strength as a contact lens, and therefore can be very suitably used as a contact lens material. Further, the presence of the aromatic ring in the material exhibits a relatively high refractive index, so that it is possible to obtain a contact lens having a thinner thickness than conventional products.

Claims (1)

[Claims] 1. General formula (I): A contact lens material comprising a styrene derivative represented by the formula (wherein R represents a methyl group, X represents a methyl group or a trimethylsilyloxyl group) and a polymer obtained by polymerizing a comonomer copolymerizable with the styrene derivative.