JP2536897B2 - Contact lens manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a contact lens, and more particularly to a method for producing a hard type contact lens having good oxygen permeability.

[Conventional technology]

In general, contact lenses have come to be used together with eyeglass lenses as means for correcting visual acuity, but at present, there are relatively few contact lens wearers as compared with eyeglass lenses. The reason for this is considered to be that the contact lens material itself used has a problem. As a contact lens material that has been widely used from the past, polymethyl methacrylate (PMMA) can be mentioned.
This PMMA lens is easy to machine, optically transparent, and has excellent durability, but it is hard to wear and has a poor oxygen permeability. It has the drawback of not being able to do so.

On the other hand, a water-containing type so-called soft contact lens has been developed in contrast to such a hard type contact lens. According to this contact lens, good oxygen permeability and a feeling of wearing can be obtained, but it has drawbacks such as low strength, and it easily becomes a culture medium of fungi. Further, it is apt to be optically inaccurate. To be done. As one means for solving such a drawback, for example, Japanese Patent Laid-Open No. 52-74
In Japanese Patent Laid-Open No. 360, a hard type solid part (1),
A composite contact lens in which a soft type hydrophilic material part (2) is chemically bonded has been introduced.

On the other hand, recently, a hard contact lens having a high oxygen permeability is being studied as a single lens material having both advantages. This type of contact lens often consists of a polymer containing silicon atoms and fluorine atoms, which are known to have good oxygen permeability. Such hard contact lenses are disclosed, for example, in JP-A-57-93315, JP-A-58-194014,
JP-A-58-127914, JP-A-60-146219, JP-A-60-
It is described in publications such as 165617.

[Problems to be solved by the invention]

However, in order to realize the required oxygen permeability with silicon atoms and fluorine atoms, it is necessary to increase the content thereof. However, doing so not only increases the cost of the contact lens, but also reduces other properties required for the contact lens, such as strength, machinability, and surface wettability.

An object of the present invention is to provide a method capable of easily manufacturing a hard type contact lens having a high oxygen transmittance without sacrificing properties such as hardness and parallel light transmittance. .

[Means for solving problems]

In order to achieve the above object, in the present invention, a contact lens is manufactured by a method including the following first step and second step.

First step: Inject a mixture obtained by mixing 100 parts by weight of a monomer composition containing a crosslinking agent, which is polymerized to give a hard type contact lens material, and 5 to 400 parts by weight of a highly compatible solvent. A step of performing a mold polymerization treatment to obtain a polymerization molded product in which the solvent is finely dispersed.

Second step: a step of forming voids having an optical size by removing the solvent finely dispersed in the polymerized molded product obtained in the first step.

Here, the "optical size" means a size of several tens of nm or less.

 Hereinafter, the present invention will be specifically described.

In the first step of the method of the present invention, a monomer composition containing a crosslinkable monomer that is polymerized to form a hard-type contact lens material is mixed with a highly compatible solvent at a constant ratio, This is a step of obtaining a polymerized molded product in which the solvent is finely dispersed by polymerizing this mixture using a casting polymerization container.

Here, the phrase “highly compatible” with respect to the solvent means that the monomer composition and the solvent are mixed to form a transparent mixture, and the mixture does not become opaque during the polymerization treatment. And, "not opaque" means that the parallel light transmittance of the obtained polymerized molded product having a thickness of 1 mm is 80% or more, preferably 85% or more. Here, the "highly compatible" solvent is dispersed and contained in the polymerization molded product in a minute state, and sufficient transparency is maintained (not opaque) even during polymer treatment.

The type of solvent actually used is selected in consideration of this compatibility with the monomer composition and the relationship between its boiling point and the polymerization temperature. Of course, it is necessary that this solvent does not inhibit the polymerization of the monomer composition.

Specific examples of the solvent that can be used include ethyl acetate, n-propyl acetate, iso-propyl acetate, and n-acetate.
-Ethyl acetates such as butyl and tert-butyl acetate, acetones, 2-butanone, ketones such as methyl isobutyl ketone, aromatic hydrocarbon compounds such as benzene and toluene, ethanol, isopropanol, n-butanol, methoxyethanol, Alcohols such as ethylene glycol, butyl ether, diglyme, ethers such as dimethyl cellosolve, saturated aliphatic hydrocarbon compounds such as hexane, heptane and cyclohexane, N, N-
Examples thereof include amides such as dimethylformamide and N, N-dimethylacetamide, and dimethyl sulfoxide. Further, a solvent comprising a fluorocarbon such as tetrachlorodifluoroethane and a fluorine-containing compound such as a fluorinated cyclic ether is also preferably used. Of course, the solvent used in the present invention is not limited to these. Further, not only one kind of this solvent but also two or more kinds can be used in combination.

The amount of the solvent used is 5 with respect to 100 parts by weight of the monomer composition.
˜400 parts by weight, preferably 8 to 350 parts by weight. This is because when the amount of solvent used is 5 parts by weight or less, the oxygen permeability of the obtained contact lens becomes low, and conversely 400%
This is because the strength of the contact lens obtained may be too small if the amount exceeds the weight range.

As the monomer of the monomer composition, as a non-crosslinking component,
Methyl (meth) acrylate, iso-propyl (meth)
Acrylate, tert-butyl (meth) acrylate, 2
-(Meth) acrylate compounds such as ethylhexyl (meth) acrylate and hydroxyethyl (meth) acrylate, vinyl compounds such as vinylpyrrolidone, styrene, p-tert-butylstyrene and vinyl acetate, allyl alcohol, 3-cyclohexylpropionic acid Examples thereof include allyl compounds such as allyl, fumaric acid esters such as diiso-propyl fumarate, ditert-butyl fumarate, and di-2-ethylhexyl fumarate.

Further, as the cross-linking component, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetraethylene glycol di (meth) acrylate, 4,4′- (Meth) acrylate compounds such as isopropylidene diphenol dimethacrylate, divinylbenzene, diisopropenylbenzene,
Examples thereof include vinyl compounds such as divinyl adipate and allyl compounds such as diallyl phthalate, diallyl succinate, and diethylene glycol bisallyl carbonate.

Further, it is preferable to use a fluorine-containing monomer as one component of the monomer composition. Specific examples of the fluorine-containing monomer include, as non-crosslinking components, 2,2,2-trifluoroethyl (meth) acrylate and 2,2,3,4,4,4-hexafluorobutyl (meth). Acrylate, 2- (perfluoro-n-hexyl) ethyl (meth) acrylate, (meth) acrylates of fluorine-containing alcohols such as di-2,2,2-trifluoroethyl fumarate, fumaric acid esters, 1, 1,2,2-tetrafluoroethyl vinyl ether,
Fluorine-containing unsaturated compounds such as vinyl ethers and allyl ethers of fluorine-containing alcohols such as 1,1,2,3,3,3-hexafluoropropylallyl ether, perfluorohexylethylene and 1-perfluorohexyl-2-methylpropene An aliphatic compound etc. can be mentioned.

As the cross-linking component, a fluorine-containing polyol such as perfluorodiethylene glycol di (meth) acrylate, perfluorohexane-1,6-diol dimethacrylate, or 4,4'-hexafluoroisopropylidene diphenol di (meth) acrylate can be used. In addition to di- or higher (meth) acrylates, the following components 1 to 3
Fluorine-containing urethane monomers composed of the three addition reaction products of

Component 1: Radical-polymerizable monomer having active hydrogen capable of addition reaction with isocyanate group Component 2: Bifunctional or higher polyisocyanate compound Component 3: Formula R _f · (OH) _h Fluorine-containing alcohol represented by formula R fluorine-containing carboxylic acid represented by _f · COOH, wherein
Fluorine-containing amine represented by R _f · NH ₂ or formula R _f · CON
Fluorine-containing amide represented by H ₂ (wherein n is 1 to 3)
And R _f represents an alkyl group having 1 to 25 carbon atoms in which some or all of hydrogen atoms are replaced by fluorine atoms, an alkylphenyl group, and a phenyl group. ) Specific examples of the component 1 include (meth) acrylic acid,
2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, allyl alcohol,
2-hydroxy-1,3-dimethacryloxypropane, tetramethylolmethanetrimethacrylate, (meth) acrylamide, N-methylol (meth) acrylamide, 1,2-bis (3-methacryloxy-2-hydroxypropoxy) ethane, p -(Meth) acryloxybenzyl alcohol etc. can be mentioned.

Specific examples of the component 2 include hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate trimer (trimer type), biuretization reaction product of hexamethylene diisocyanate, 2-isocyanatopropyl- 2,6-diisocyanate hexanoate and the like can be mentioned.

Specific examples of the component 3 include 2,2,3,3-tetrafluoro-1-propanol, 2,2,3,4,4,4-hexafluorobutanol and 2- (perfluoro-n-hexyl) ethanol. , 1,1,1,3,3,3-hexafluoro-2-propanol, 3- (perfluoro-n-octyl) propane-1,
2-diol, pentafluorophenol, 3,5-bis (trifluoromethyl) phenol, perfluorooctanoic acid, perfluoropropionic acid, 3,5-dichloro-
2,4-difluoroaniline, 4-trifluoromethylaniline, 4-trifluoromethylbenzamide, 4-trifluoromethylbenzoic acid and the like can be mentioned.

The above compounds are examples, and each of the components 1 to 3 is not limited to the examples. In addition, each component is
Not only one kind but also two or more kinds may be used in combination depending on desired characteristics.

The addition reaction of these components 1 to 3 may be performed prior to the polymerization treatment of the monomer composition. Since the urethane monomer produced is usually very viscous, it is preferable to carry out the addition reaction after previously mixing with the other monomers of the components 1 to 3 and the solvent. Further, this addition reaction can be carried out in a multi-step manner, for example, in such a manner that the reaction of the component 2 and the component 3 is performed in advance, and then the component 1 is added to complete the reaction. It is also possible to carry out simultaneously with the polymerization.

Since this addition reaction may occur only by heating, it is possible to obtain a fluorine-containing urethane monomer by this, but usually, for example, dibutyltin dilaurate, 1,2,2,6,6-pentamethyl. It is preferable to use a reaction initiator commonly used in the production of polyurethane such as -4-hydroxypiperidine, stannas octoate, and dimethyltin dichlorite. The amount of these reaction initiators used is 0.001 to 3.0 with respect to 100 parts by weight of the total of components 1 to 3.
It is desirable that the amount is parts by weight.

The ratio of the above components 1 to 3 is the molar amount of isocyanate groups in the polyisocyanate compound of component 2 [NC
Ratio [H] / [NCO] of the total molar amount [H] of active hydrogen in the radical-polymerizable monomer of component 1 and the fluorine-containing compound of component 3 to O] (this ratio is hereinafter referred to as "active hydrogen equivalent"). It is desirable that the value of) be close to 1, particularly preferably more than 0.85 and less than 1.5.

Further, it is preferable that the organism of the monomer composition contains a silicon-containing monomer, and specific examples thereof include tris (trimethylsiloxy) siloxypropyl (meth) acrylate and pentamethyldisiloxy as non-crosslinking components. Examples thereof include propyl (meth) acrylate, methyldi (trimethylsiloxy) silylpropyl glycerol (meth) acrylate and tris (pentamethyldisiloxy) silylpropyl (meth) acrylate.

Examples of the cross-linking component include bis (methacryloxypropyl) tetramethyldisiloxane, bis (methacryloxybutyl) tetramethyldisiloxane, and divinyldimersilane.

The above compounds are examples, and the present invention is not limited thereto. The silicon-containing monomer composition may be used alone or in combination of two or more.

It is particularly preferable that not only one of the fluorine-containing monomer and the silicon-containing monomer preferable as the above-described monomer but also both are contained in the monomer composition.

In the first step of the method of the present invention, a composition for polymerization consisting of the monomer composition, a solvent and a necessary polymerization initiator is injected into a desired shape, for example, a lens-shaped mold or container,
It is achieved by performing a cast polymerization treatment. This makes it possible to obtain the contactor lens directly,
The obtained contact lens can be subjected to machining or polishing treatment using a known technique. Further, the contact lens of the present invention can be manufactured by obtaining a rod-shaped, block-shaped or sheet-shaped polymerized product and cutting or polishing the polymerized product.

The second step of the method of the present invention is a step of forming voids having an optical size by removing the solvent finely dispersed in the polymerized molding obtained in the first step.

Specifically, the optimum means is selected depending on the shape of the polymerized molded product, the type of solvent mixed in the monomer composition, and the like.

The most gentle method is the solvent replacement method. According to this means, the solvent in the polymerized molded product is replaced by immersing the polymerized molded product obtained in the first step in a large amount of extraction solvent, and then the polymerized molded product is taken out, dried and replaced by extraction. The solvent is removed by evaporating the solvent.

The feature of this means is that the solvent can be removed under relatively mild conditions, so that the polymerization molded product is not significantly deformed, and if an appropriate extraction solvent is selected, it is mixed with the monomer composition. That is, the solvent can be sufficiently removed regardless of the kind of the solvent.

Here, as the extraction solvent, it is preferable to use an organic solvent that is well miscible with the solvent mixed with the monomer composition and does not have a high boiling point. Of course, it is necessary that the polymerized product does not denature.

As the extraction solvent that can be used, those already mentioned as the solvent for mixing with the monomer composition can be mentioned, and specifically, ethyl acetate, n-propyl acetate, acetic acid can be used.
Acetates such as iso-propyl, acetone, 2-
Ketones such as butanone, aromatic hydrocarbon compounds such as benzene and toluene, lower alcohols such as methanol, ethanol and isopropanol, saturated aliphatic hydrocarbon compounds such as hexane, heptane and cyclohexane, dichloromethane, chloroform, tetrachloride Examples thereof include halogenated hydrocarbons such as carbon and various freons. In addition, the drying process for removing the extraction solvent that follows the extraction process is preferably performed at a low temperature so that the advantage of this means is not impaired.

The second step of the method of the present invention can also be performed by a vacuum drying method. This means is effective when the solvent mixed with the monomer composition is relatively easy to exert. However, when the reduced pressure is suddenly applied, the solvent may be rapidly evaporated to cause cracks or the like in the polymerized molded product. When using this means, it is possible to heat at the same time.

Further, the second step can be carried out by a drying method by heating, but the thermal influence on the removal rate of the solvent and the polymerized molded product is relatively large.

As mentioned above, the typical means for removing the solvent from the polymerization molded product has been mentioned, but it is preferable that the polymerization molded product has a thin shape in any case, and in this case,
Removal of solvent can be achieved with high efficiency. A final molding step can be performed subsequent to the second step.

〔effect〕

According to the method of the present invention, as is clear from the description of the examples given later, it is possible to easily form a hard contact lens having a high oxygen transmittance without significantly lowering various properties such as hardness and parallel light transmittance. Can be manufactured.

The reason for this is as follows. That is, since what is subjected to the cast polymerization treatment in the first step is a transparent mixture composed of the monomer composition and a solvent having high compatibility, the solvent is extremely mixed in the obtained polymerization molded product. It exists in a finely dispersed state. Then, voids are formed in the polymerized molded product after the solvent is removed, but the solvent contained in the polymerized molded product obtained through the first step has a very fine dispersion state, It is considered that the voids formed are sufficiently small and have an optical size (several tens of nm or less) or less, and thus sufficient transparency is maintained and good void permeability is obtained by the voids.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited thereto.

Example 1 30 parts by weight of tert-butyl methacrylate, 2,2,3,4,4,
62 parts by weight of 4-hexafluorobutyl methacrylate,
8 parts by weight of neopentyl glycol dimethacrylate were mixed to obtain a monomer composition, and acetic acid n- was used as a solvent.
15 parts by weight of butyl and 1.4 parts by weight of tert-butyl peroxypivalate as a polymerization initiator were added to a test tube and injected at 45 ° C for 8 hours, 60 ° C for 4 hours, 80 ° C for 2 hours, Polymerization was performed according to a heating program at 90 ° C. for 1 hour.

After that, take out the polymerized molded product from the test tube and make it 0.8m thick.
It was sliced into a disc of m and immersed in 200 ml of ethanol. After a lapse of one day, the ethanol was replaced with a new one, and immersion was carried out for another day. After the polymerized molded product taken out from ethanol was dried at room temperature, it was further dried in a vacuum dryer to obtain a contact lens of the present invention. The weight change of the disc-shaped polymer before and after the solvent substitution method was 12%, which was 122 mg, which was 138 mg.

This contact lens was colorless and transparent, and the parallel light transmittance was measured by "HAZE METER TC-H III" (manufactured by Tokyo Denshoku Co., Ltd.) and found to be 95% or more. The oxygen permeability of this contact lens was measured using a Seikaken-type oxygen permeability meter and found to be 11 × 10
^It showed a high value of ^-11 cc · cm ² · sec.mmHg. The value of the oxygen transmission rate is 0.4 mm, 0.3 mm, 0.2 according to the literature (Magazine "Nippon Contact Lenses" Vol. 26, page 208, 1984).
Oxygen permeability was measured for samples with three thicknesses of mm and an extrapolated value of infinite thickness was adopted. In addition, the Vickers hardness of this contact lens can be measured with the "Vickers hardness meter AVK-
It was 10.6 when measured using "A" (manufactured by Akashi Seisakusho).

Comparative Example 1 A polymerized molded product was obtained in the same manner as in Example 1 except that n-butyl acetate was not added, and thus the solvent removal step was not performed. Regarding this, a parallel light transmittance, oxygen was obtained in the same manner as in Example 1. The transmittance and Vickers hardness were measured. The results are as follows.

Parallel light transmittance: 95% or more Oxygen transmittance: 8 × 10 ⁻¹¹ cc · cm ² · sec.mmHg Vickers hardness: 11.8 Example 2 3- (perfluoro-n-octyl) propane-1 was placed in an Erlenmeyer flask. 1,2-diol 9.8 parts by weight, isophorone diisocyanate 9.1 parts by weight, hydroxypropyl methacrylate 6.1 parts by weight, 2- (perfluorohexyl) ethyl methacrylate 65 parts by weight, tert-butyl methacrylate 10 parts by weight, acetic acid n- 10 parts by weight of butyl,
Dibutyltin dilaurate (0.04 parts by weight) was added, and urethanization reaction was carried out at 60 ° C. for 3 hours. After the reaction, 1.5 parts by weight of tert-butyl peroxypivalate was added, and this was placed in a test tube and polymerized in the same manner as in Example 1.

After the completion of polymerization, the thickness of the polymerized molded product taken out from the test tube
It was sliced into a 0.8 mm disc shape, vacuum dried at room temperature for one day in a vacuum drier, and further dried at 50 ° C. for 2 hours to obtain a pale yellow transparent contact lens of the present invention. The weight change of the disc-shaped polymer before and after this vacuum drying was 14
It was a 7% decrease from 7 mg to 136 mg.

For this contact lens, the parallel light transmittance, the oxygen transmittance, and the Vickers hardness were measured in the same manner as in Example 1. The results are as follows.

Parallel light transmittance: 95% or more Oxygen transmittance: 17 × 10 ^-11 cc · cm / cm ² · sec.mmHg Vickers hardness: 7.8 Comparative Example 2 n-Butyl acetate is not added, and therefore the vacuum drying step is not performed. A polymerized molded product was obtained in the same manner as in Example 2 except for the above, and the parallel light transmittance, oxygen transmittance, and Vickers hardness were measured in the same manner as in Example 1. The results are as follows.

Parallel light transmittance: 90% Oxygen transmittance: 14 × 10 ^-11 cc · cm / cm ² · sec.mmHg Vickers hardness: 8.5 Example 3 Hexamethylene diisocyanate trimer, which is a trifunctional isocyanate (trimmer type, NCO content 21.3% by weight) 17.4 parts by weight, 2- (perfluorohexyl) ethanol 16.2 parts by weight, 2- (perfluorooctyl) ethyl methacrylate 50 parts by weight, tert-butyl methacrylate 10 parts by weight, dimethyl cellosolve 20 parts by weight Parts and 0.04 part by weight of dibutyltin dilaurate were placed in a reaction vessel and subjected to a urethanization reaction at 60 ° C. for 1 hour, and then 6.4 parts by weight of hydroxypropyl methacrylate was added to continue the reaction. After the reaction, tert-butyl peroxypivalate
Example 1 was prepared by adding 1.5 parts by weight to a test tube.
Polymerization was carried out in the same manner as in.

After the completion of polymerization, the thickness of the polymerized molded product taken out from the test tube
It was sliced into a 0.8 mm disk shape, and the solvent was removed by the same solvent substitution method as in Example 1 to obtain a light yellow transparent contact lens of the present invention. The weight change of the disc-shaped polymer before and after this solvent substitution method was 15%, which was 151 mg to 129 mg.

For this contact lens, the parallel light transmittance, the oxygen transmittance, and the Vickers hardness were measured in the same manner as in Example 1. The results are as follows.

Parallel light transmittance: 95% or more Oxygen transmittance: 28 × 10 ^-11 cc · cm / cm ² · sec.mmHg Vickers hardness: 7.3 Comparative Example 3 Except that no dimethyl cellosolve is added and therefore the solvent removal step is not performed A polymerized molded product was obtained in the same manner as in Example 3, and the parallel light transmittance, oxygen transmittance, and Vickers hardness of this were measured in the same manner as in Example 1. The results are as follows.

Parallel light transmittance: 90% Oxygen transmittance: 20 × 10 ^-11 cc ・ cm / cm ²・ sec.mmHg Vickers hardness: 8.5

Claims (1)

(57) [Claims] 1. A method of manufacturing a contact lens, comprising the following first step and second step. First step: Inject a mixture obtained by mixing 100 parts by weight of a monomer composition containing a crosslinking agent, which is polymerized to give a hard type contact lens material, and 5 to 400 parts by weight of a highly compatible solvent. A step of performing a mold polymerization treatment to obtain a polymerization molded product in which the solvent is finely dispersed. Second step: a step of forming voids having an optical size by removing the solvent finely dispersed in the polymerized molded product obtained in the first step.