JPH08184786A - Hydrous soft contact lens and its production - Google Patents

Abstract

PURPOSE: To provide a hydrous soft contact lens which has a high hydrous property and excellent transparency and has not only adequate strength as a hydrous soft contact lens but excellent shape stability as well and a method capable of making continuous mass production of this hydrous soft contact lens at a low cost in a short period of time, CONSTITUTION: This hydrous soft contact lens consists of a polymer formed by crosslinking and polymerizing a vinyl monomer component contg. a hydrophilic (meth)acryl amide and a cellulose deriv. of 3 to 75wt.% content of the hydroxypropoxyl group in one molecule. This process for producing the hydrous soft contact lens comprises crosslinking and polymerizing the vinyl monomer component by compatibilizing the vinyl monomer component and the cellulose deriv.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrous soft contact lens and a method for producing the same. More specifically, it has a high hydrous content, is excellent in transparency, and of course has an appropriate mechanical strength as a hydrous soft contact lens, as well as a hydrous soft contact lens excellent in shape stability, and The present invention relates to a method capable of continuously mass-producing the hydrous soft contact lens in a short time and at low cost.

[0002]

2. Description of the Related Art In recent years, soft contact lenses having a high water content, particularly disposable type high water content soft contact lenses, have been extensively researched, and such disposable type high water content soft contact lenses are manufactured. In this case, it is particularly required to use inexpensive materials to reduce the cost and continuously mass-produce.

By the way, various studies and developments have been made so far on hydrous gels and manufacturing methods thereof, and use of such hydrous gels for contact lenses has been proposed.

For example, 2-hydroxyethyl methacrylate, methacrylic acid, N-vinylpyrrolidone, N, N-
Hydrogels obtained by polymerizing hydrophilic monomers such as dimethylacrylamide are used for contact lenses. However, when such a hydrophilic monomer is used, if the water content of the obtained hydrogel is increased, its mechanical strength tends to decrease, and both the water content and the mechanical strength are increased. It had the drawback of being difficult.

Therefore, it has been proposed to use a raw material having a high molecular weight in order to avoid such a decrease in mechanical strength due to the improvement of the water content.

For example, Japanese Patent Publication No. 59-1744 discloses a group obtained by copolymerizing a hydrophilic (meth) acrylic polymer obtained by polymerizing a hydroxyalkyl (meth) acrylate and a hydrophobic monomer. A self-reinforcing hydrogel containing water as a material is disclosed. However, there is a problem in that it takes time to carry out the polymerization in two stages, and the cost increases. In addition, Japanese Patent Publication No. 1412
Japanese Unexamined Patent Publication (Kokai) No. 4 describes a method for producing a hydrogel by introducing a polymerizable group into an existing hydrophilic polymer compound such as polyethylene glycol, and then mixing and polymerizing the mixture with a monomer. However, since such a method is basically a two-step polymerization method, there is a problem that it takes time to produce the hydrogel and it is difficult to mass-produce the hydrogel at low cost.

Further, a method using a cellulose derivative as a contact lens material has been proposed because it has good biocompatibility and relatively good oxygen permeability.

For example, Japanese Patent Application Laid-Open No. 53-52447 describes a method of obtaining a contact lens by mixing a low molecular weight compatible plasticizer with a cellulose ester or a cellulose ether and, for example, by injection molding.
However, such a method can be suitably used for obtaining a non-hydrous contact lens basically, but since there is no cross-linking portion in the polymer, even if a hydrophilic cellulose ester or cellulose ether is used. However, there is a problem in that the shape required for a contact lens cannot be maintained when water is included.

Further, US Pat. No. 4,231,905 describes a method of obtaining a contact lens by dissolving a small amount of cellulose ether or cellulose ester in methyl methacrylate and then polymerizing and dissolving it. However, such a method can also be adopted when obtaining a non-hydrated contact lens, but it becomes difficult to apply to the production of a hydrated contact lens because it becomes cloudy when hydrated.

On the other hand, it has been attempted to use a cellulose derivative for a water-containing contact lens, for example, the following.

In Japanese Patent Laid-Open No. 2-168958, a regenerated cellulose prepared by adding a polyacid having two or more hydroxyl groups in the molecule, a polyhydric alcohol or the like to a regenerated cellulose dissolved in an organic solvent as a crosslinking agent. There is described a method for obtaining a hydrous contact lens by forming a crosslinked structure by a hydrogen bond generated between a gel and a crosslinking agent to cause gelation, and then substituting water for the organic solvent in the gel. However, in such a method, since the polymer molecular chains are cross-linked by hydrogen bonds, the hydrogen bonds are decomposed by a slight environmental change. Therefore, reproducibility and the water-containing contact lens obtained are There is a problem of poor shape stability.

Further, in JP-A-5-237142, a crosslinking agent such as epichlorohydrin or ethylene glycol diglycidyl ether is added to an alkaline aqueous solution of cellulose or a cellulose derivative to cause a cross-linking reaction. A method of obtaining a lens is described. However, such a method has a problem of poor reproducibility because it is difficult to cause a uniform reaction because an ester bond or an ether bond is formed in an aqueous solution to form a crosslinked structure.

Further, in JP-A-5-86101, hydroxyethyl cellulose is reacted with, for example, 2-isocyanatoethyl methacrylate in a dimethylsulfoxide solution, and dimethyl of hydroxyethyl cellulose having a methacryloyl group as a side chain is obtained. A method is described in which a monomer such as methylmethacrylate is added to a sulfoxide solution to cause a reaction, and then the organic solvent in the gel is replaced with water to obtain an intended hydrous contact lens. However, since the compatibility of hydroxyethyl cellulose and organic solvent is not so good in such a method, the reaction must be carried out in a dilute solution of the polymer, and as a result, the obtained gel has low mechanical strength. And many manufacturing processes,
There is a problem that the cost becomes high.

Therefore, it is possible to establish a soft contact lens having high water content, excellent shape stability, and moderate mechanical strength, and a method capable of continuously mass-producing the soft contact lens at low cost. Long-awaited.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art and has not only excellent transparency but also appropriate mechanical strength and shape stability. An object of the present invention is to provide an excellent hydrous soft contact lens, for example, a disposable type hydrous soft contact lens, and a method capable of continuously mass-producing the hydrous soft contact lens in a short time and at low cost. .

[0016]

Means for Solving the Problems The present invention comprises a polymer obtained by cross-linking and polymerizing a vinyl monomer component containing hydrophilic (meth) acrylamide, and the content of hydroxypropoxyl group in one molecule is 3 to 75% by weight. % Of cellulose derivative, a vinyl monomer component containing hydrophilic (meth) acrylamide, and a cellulose derivative having a hydroxypropoxyl group content in one molecule of 3 to 75% by weight. The present invention relates to a method for producing a hydrous soft contact lens, which is characterized in that the vinyl monomer component is cross-linked and polymerized.

[0017]

Functions and Examples As described above, the hydrous soft contact lens of the present invention comprises a polymer obtained by crosslinking and polymerizing a vinyl monomer component containing hydrophilic (meth) acrylamide, and a hydroxypropoxyl group in one molecule. Is a cellulose derivative having a content of 3 to 75% by weight, and the method for producing the hydrous soft contact lens is as follows: a vinyl monomer component containing hydrophilic (meth) acrylamide and a hydroxypropoxyl group in one molecule. Quantity 3
˜75% by weight of a cellulose derivative is made compatible with each other, and the vinyl monomer component is cross-linked and polymerized.

In the method for producing the hydrous soft contact lens of the present invention, since the vinyl monomer component is substantially hard to react with the cellulose derivative, the vinyl monomer component is not reacted with the cellulose derivative, It alone can be cross-linked to form a polymer. Therefore, the polymer obtained by cross-linking and polymerizing only the vinyl monomer component and the cellulose derivative are entangled with each other, and have a high water content and an appropriate strength as a water-containing soft contact lens, and have transparency and molding processability. Excellent composite polymer can be obtained.

As described above, the hydrous soft contact lens of the present invention is usually made of a composite polymer having a structure in which a polymer obtained by cross-linking and polymerizing only such a vinyl monomer component and a cellulose derivative are entangled with each other. However, the polymer obtained by cross-linking polymerization of the vinyl monomer component and the cellulose derivative are, for example, a polyfunctional compound capable of cross-linking the cellulose derivative within a range that does not impede the object of the present invention. It may be crosslinked via.

One of the major characteristics of the method for producing a hydrous soft contact lens of the present invention is that a cellulose derivative having a specific amount of a specific substituent is used.

The cellulose derivative is hydrophilic (meth).
Since it has excellent compatibility with the vinyl monomer component containing acrylamide, a composite polymer can be easily formed, and since it has hydrophilicity, the water content of the composite polymer can be increased and white turbidity Since it does not occur and has a rigid molecular chain structure, the shape stability of the composite polymer is enhanced. Also,
The cellulose derivative is not likely to be eluted from the composite polymer even when the composite polymer is made to contain water, and the hydrous soft contact lens obtained from the composite polymer has excellent safety.

The vinyl monomer component used in the present invention contains hydrophilic (meth) acrylamide.

The above-mentioned hydrophilic (meth) acrylamide is a substance that is substantially unreactive with and compatible with the cellulose derivative, as long as it does not deteriorate the transparency of the obtained hydrous soft contact lens. Good. Typical examples of the hydrophilic (meth) acrylamide include, for example, (meth) acrylamide; N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, and other alkyl groups having an alkyl group having 1 to 2 carbon atoms. (Meth) acrylamide or alkyl group having 1 to 2 carbon atoms
Examples of dialkyl (meth) acrylamide,
These may be used alone or in combination of two or more. Among these, dialkyl (meth) acrylamides having 1 to 2 carbon atoms in the alkyl group are preferable because they are easy to handle, have excellent compatibility with cellulose derivatives, and improve the transparency of the resulting hydrous soft contact lens. preferable.

The total amount of the vinyl monomer component may be the hydrophilic (meth) acrylamide or a part thereof may be the hydrophilic (meth) acrylamide. When the content of the hydrophilic (meth) acrylamide is too low, the viscosity tends to be too high when the vinyl monomer component and the cellulose derivative are compatibilized with each other, which makes it difficult to handle. The content of the functional (meth) acrylamide is preferably 40 to 100% by weight of the vinyl monomer component, and 50% by weight.
It is more preferable that the above is satisfied. In order to sufficiently improve the mechanical strength of the cellulose derivative and prevent the resulting hydrous soft contact lens from becoming brittle when hydrous, the content of the hydrophilic (meth) acrylamide is More preferably, it is 90% by weight or less of the vinyl monomer component.

In addition to the hydrophilic (meth) acrylamide, the vinyl monomer component may contain a hydrophobic vinyl monomer for the purpose of further improving the mechanical strength of the resulting hydrous soft contact lens. Good.

As the above-mentioned hydrophobic vinyl monomer, any one may be used as long as it is substantially unreactive with and compatible with the cellulose derivative, and typical examples thereof include methyl (meth) acrylate and ethyl (meth) acrylate. ,
For example, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate and the like, for example, alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms; fluoroalkyl group having 3 to 12 carbon atoms in a fluoroalkyl group ( (Meth) acrylate; siloxanylalkyl (meth) acrylate having a siloxanylalkyl group having 3 to 12 carbon atoms; vinyl acetate; styrene, a styrene-based monomer such as alkylstyrene having an alkyl group having 1 to 6 carbon atoms; alkyl Alkenes such as alkene having 2 to 18 carbon atoms in the group and haloalkene having 2 to 18 carbon atoms in the alkyl group; (meth) acrylonitrile and the like, which may be used alone or in admixture of two or more. You can Among these, the compatibility with the cellulose derivative is good, and the effect of improving the mechanical strength of the hydrous soft contact lens is large,
An alkyl (meth) acrylate in which the alkyl group has 1 to 12 carbon atoms is preferable.

If the content of the hydrophobic vinyl monomer is too large, the water content of the obtained hydrous soft contact lens tends to decrease, so that the content of the vinyl monomer component is 0 to 60% by weight. Preferably,
It is more preferably 50% by weight or less. In order to fully bring out the effect of improving the mechanical strength of the hydrous soft contact lens by using the hydrophobic vinyl monomer, the content of the hydrophobic vinyl monomer is 10% by weight of the vinyl monomer component. It is more preferable that the above is satisfied.

The cellulose derivative used in the present invention is
It improves the mechanical strength of the resulting hydrous soft contact lens and exhibits the effect of suppressing polymerization shrinkage.

The hydrous soft contact lens of the present invention has a mechanical strength reinforced to a certain extent by a polymer composed of a vinyl monomer component having a high molecular weight, and further, the cellulose derivative has sufficient mechanical strength as a hydrous soft contact lens. Strength is imparted. Also, since cellulose derivatives are not monomers,
A system to which such a cellulose derivative is added has a lower polymerization shrinkage rate than a system containing only a vinyl monomer component, and a hydrous soft contact lens having a desired shape can be obtained.

Further, since the cellulose derivative used in the present invention has hydrophilicity and excellent compatibility with the vinyl monomer component, it is compatible with the vinyl monomer component so as to have a uniform composition. Unlike the case of using a water-insoluble polymer substance, cloudiness does not occur in a hydrous soft contact lens without controlling the initial polymerization rate.

The cellulose derivative has the formula (I):

[0032]

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Some of the hydroxyl groups in the cellulose having the repeating unit represented by are substituted with hydroxypropoxyl groups, and the content of hydroxypropoxyl groups in one molecule is 3 to 75% by weight. Is.

In the cellulose derivative, unless the object of the present invention is impaired, part of the hydroxyl groups in the cellulose is not only a hydroxypropoxyl group but also a hydroxypropoxyl group such as an alkoxyl group or a carboxyl group. It may be substituted with a substituent other than.

Typical examples of the cellulose derivative used in the present invention include, for example, the general formula (II):

[0036]

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(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydroxypropoxyl group, an alkoxyl group having 1 to 12 carbon atoms, a carboxyl group, a carboxybenzoyl group, An acetoxyl group, a succinooxyl group or a hydroxyl group, wherein at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is a hydroxypropoxyl group, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are not all hydroxyl groups at the same time).

Specific examples of the compound represented by the general formula (II) include hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylethylcellulose, hydroxypropylbutylcellulose, hydroxypropylmethylcellulose phthalate and hydroxypropylmethylcellulose acetate succinate. can give.

Since the cellulose derivative containing a specific amount of hydroxypropoxyl group used in the present invention has substantially no reactivity with the vinyl monomer component and has excellent compatibility, the vinyl monomer is used. Since the components are entangled with the polymer obtained by cross-linking polymerization, it has an appropriate mechanical strength and high water content as a water-containing soft contact lens, and a good composite polymer with excellent transparency and molding processability can be easily obtained. available.

If the content of the hydroxypropoxyl group in one molecule of the cellulose derivative is too small, the compatibility between the cellulose derivative and the vinyl monomer component will decrease, and the resulting hydrous soft contact will be obtained. Since the lens tends to become cloudy, it is 3% by weight or more, preferably 5% by weight or more, more preferably 6% by weight or more. The content of such hydroxypropoxyl group is
If the amount is too large, the hydrophilicity of the cellulose derivative is lowered, and the water content of the obtained hydrous soft contact lens is lowered, so that it is 75% by weight or less, preferably 70% by weight or less, and more preferably 65% by weight or less. It is less than or equal to weight%.

Since it is difficult to directly measure the molecular weight of the cellulose derivative used in the present invention, the molecular weight is indirectly defined by the viscosity of the aqueous solution of the cellulose derivative in the present invention.

When the molecular weight of the cellulose derivative is too small, that is, when the viscosity of the aqueous solution is too low, it is a low molecular weight substance, so that the mechanical strength of the obtained hydrous soft contact lens is improved. Since the hardening effect tends not to be sufficiently exhibited, the viscosity (20 ° C.) of the 2% aqueous solution is 0.2 cP or more, preferably 0.5 cP or more, more preferably 1 c.
It is preferably P or more. When the molecular weight of the cellulose derivative is too large, that is, when the viscosity of the aqueous solution is too high, the viscosity of the system that is compatible with the vinyl monomer component becomes high because it is a high molecular weight substance. However, the viscosity of the 2% aqueous solution (20 ° C.) is 10000 c because it tends to be difficult to handle.
P or less, preferably 8000 cP or less, more preferably 6000 cP or less.

In the production method of the present invention, the vinyl monomer component and the cellulose derivative having a hydroxypropoxyl group content in one molecule of 3 to 75% by weight are made compatible with each other. The weight ratio with the cellulose derivative (vinyl monomer component / cellulose derivative) is such that if the vinyl monomer component is too small, that is, if the cellulose derivative is too much, the viscosity of the system in which both are compatible increases. It tends to be difficult to handle because it is too much, so the weight ratio is 1
It is desirable to adjust it to 5/85 or more, preferably 30/70 or more, and when the vinyl monomer component is too much, that is, when the cellulose derivative is too little, the water-containing softness of the cellulose derivative is used. Since the effect of improving the mechanical strength of the contact lens and the effect of suppressing polymerization shrinkage tend not to be sufficiently manifested, it is 95/5 or less, preferably 90 /
It is desirable to adjust the value to 10 or less.

For example, after adjusting the blending amounts of the vinyl monomer component and the cellulose derivative so as to obtain the above weight ratio, they are made compatible with each other and the vinyl monomer component is cross-linked and polymerized. Cross-linking polymerization with a water-soluble vinyl monomer is preferable from the viewpoint of further improving the shape stability of the obtained hydrous soft contact lens.

The crosslinkable vinyl monomer may be any one that can crosslink only the vinyl monomer component, and typical examples thereof include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate and triethylene glycol di (meth) acrylate. Ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth)
Acrylate, vinyl (meth) acrylate, 1,4-
Di-, tri- or tetravinyl compounds such as butanediol di (meth) acrylate, N, N-methylenebis (meth) acrylamide, hexamethylene bismaleimide, divinylbenzene, trimethylolpropane tri (meth) acrylate, diallyl succinate, diethylene glycol bis Allyl compounds such as allyl carbonate,
Examples thereof include allyl vinyl compounds such as allyl (meth) acrylate, and these can be used alone or in admixture of two or more. Among these, from the viewpoint of easy handling and good crosslinking reactivity,
Ethylene glycol di (meth) acrylate is preferred.

If the amount of the crosslinkable vinyl monomer is too small, the effect of improving the crosslinking reactivity of the vinyl monomer component due to the use of the crosslinkable vinyl monomer tends not to be sufficiently exhibited. 0.01% by weight of the total amount of the vinyl monomer component
It is desirable that the amount is adjusted to be not less than 0.1% by weight, more preferably not less than 0.2% by weight. If the amount of the crosslinkable vinyl monomer is too large, the water content of the resulting hydrous soft contact lens tends to decrease, or the mechanical strength tends to decrease. It is desirable to adjust the total amount to 10% by weight or less, preferably 5% by weight or less.

The features of the manufacturing method of the present invention are, as described above,
By cross-linking and polymerizing the vinyl monomer component by itself, a composite polymer can be obtained from a polymer obtained by cross-linking and polymerizing such vinyl monomer components and a cellulose derivative, but further improving the mechanical strength of such a composite polymer. For the purpose of hardening, it is preferable to crosslink not only the vinyl monomer component but also the cellulose derivative by itself. By cross-linking such cellulose derivatives, a polymer obtained by cross-linking and polymerizing the vinyl monomer component and a cross-linked cellulose derivative are entangled with each other to obtain a composite polymer, and the composite polymer has a reduced water content. However, there is no cloudiness, and the mechanical strength is extremely improved.

By cross-linking the cellulose derivative with, for example, a polyfunctional compound capable of cross-linking with the cellulose derivative, it is possible to further improve the mechanical strength of the obtained water-containing soft contact lens. It is preferable from the viewpoint that when a soft contact lens is made to contain water, there is no possibility of elution of the cellulose derivative.

The polyfunctional compound is capable of reacting with the hydroxyl group in the cellulose derivative to crosslink only the cellulose derivative. For example, an isocyanate group, a carboxyl group, an aldehyde group, an amide group, a hydroxyl group or a chlorosulfone group. Any compound having a functional group may be used. As typical examples thereof, for example, polyisocyanate which is a multimer of hexamethylene diisocyanate, hexamethylene diisocyanate, paraformaldehyde,
Examples thereof include phthalic anhydride, methylated melamine resin, polyvinyl alcohol, boric acid, titanate ester, and vanadium ion. As the polyisocyanate, which is a multimer of hexamethylene diisocyanate,
For example, there are those containing a trimer of hexamethylene diisocyanate (trifunctional) as a main component and a hexamer of hexamethylene diisocyanate (tetrafunctional) in addition to the trimer. As a typical example of the polyisocyanate, for example, Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd., number average molecular weight: 700, isocyanate group content: 21.3% by weight, number of isocyanate groups in one molecule: average about) 3.55) and Coronate HK (manufactured by Nippon Polyurethane Industry Co., Ltd., number average molecular weight: 1000, content of isocyanate group: 20% by weight, number of isocyanate groups in one molecule: about 4.76 on average) Other examples include block-type polyisocyanates. These polyfunctional compounds can be used alone or as a mixture of two or more kinds, but among them, from the viewpoints of easy handling, exhibiting an appropriate crosslinking rate, and excellent stability of crosslinking. Polyisocyanate, which is a multimer of hexamethylene diisocyanate, is preferable.

The blending amount of the polyfunctional compound capable of crosslinking with the cellulose derivative varies depending on the types of the cellulose derivative and the polyfunctional compound used, and is not particularly limited. Usually, the hydroxyl group and the polyfunctional compound in the cellulose derivative are mixed with each other. It is considered to depend on the ratio of the functional group to the functional compound. When the amount of the functional group in the polyfunctional compound with respect to the amount of the hydroxyl group in the cellulose derivative is too small, the crosslinking effect of the cellulose derivative by using the polyfunctional compound is not sufficiently expressed, and Since the mechanical strength of the water-containing soft contact lens tends to not be improved so much, the equivalence ratio (hydroxyl group / functional group) between the hydroxyl group in the cellulose derivative and the functional group in the polyfunctional compound is 150.
/ 1 or less, especially 100/1 or less, and when the amount of the functional group is too large relative to the amount of the hydroxyl group, the water content of the obtained water-containing soft contact lens is lowered. Therefore, it is preferable to adjust the equivalence ratio to 2/1 or more, especially 5/1 or more.

In the method for producing a hydrous soft contact lens of the present invention, first, a vinyl monomer component and a cellulose derivative are blended in a predetermined blending ratio, and both are made compatible with each other. After blending a predetermined amount of a polyfunctional compound that is a crosslinking agent of a crosslinkable vinyl monomer or a cellulose derivative that is, a polymerization initiator such as a radical polymerization initiator or a photopolymerization initiator is added to this, The vinyl monomer components are cross-linked and polymerized, and the cellulose derivatives are cross-linked as necessary.

As a specific example of such a method, for example, a radical polymerization initiator is added to a system in which the vinyl monomer component and the cellulose derivative are compatible with each other, and then, for example, about 0.5 to 60 at about 30 to 150 ° C. Cross-linking polymerization by heating for minutes to carry out cross-linking polymerization (heat-polymerization method), after blending a photo-polymerization initiator, and then irradiating a light ray (for example, ultraviolet ray) having a wavelength corresponding to the absorption band of activation of the photo-polymerization initiator. Examples thereof include a method (photopolymerization method), a method in which a heat polymerization method and a photopolymerization method are combined to perform cross-linking polymerization.

When the above-mentioned heat polymerization method is used, heating may be carried out in a thermostat or a thermostatic chamber, irradiation with electromagnetic waves such as microwaves may be carried out, and heating may be carried out stepwise. . Further, when the photopolymerization method is used, a sensitizer may be further added.

In the production of the hydrous soft contact lens of the present invention, it is preferable to employ the usual bulk polymerization method because the hydrous soft contact lens can be efficiently obtained, but the cellulose used in the present invention is preferable. Since the derivative has compatibility with ordinary solvents,
If necessary, a solution polymerization method using an organic solvent such as dimethyl sulfoxide, acetone, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, and hexamethylphosphoramide may be adopted. it can.

As typical examples of the radical polymerization initiator, for example, azobisisobutyronitrile, azobisdimethylvaleronitrile, benzoyl peroxide, t-
Butyl hydroperoxide, cumene peroxide and the like can be mentioned.

Typical examples of the photopolymerization initiator include benzoin, methyl orthobenzoyl benzoate, methyl benzoyl formate, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and benzoin-n-butyl ether. Benzoin-based photopolymerization initiator; 2-hydroxy-2-methyl-1-phenylpropan-1-one, p-isopropyl-α-hydroxyisobutylphenone, pt-butyltrichloroacetophenone, 2,2-dimethoxy-2- Phenone-based photopolymerization initiators such as phenylacetophenone, α, α-dichloro-4-phenoxyacetophenone, N, N-tetraethyl-4,4-diaminobenzophenone; 1-hydroxycyclohexyl group Niruketon; 1-phenyl -
1,2-propanedione-2- (o-ethoxycarbonyl) oxime; thioxanthone photoinitiators such as 2-chlorothioxanthone and 2-methylthioxanthone;
Examples include dibenzosubarone; 2-ethylanthraquinone; benzophenone acrylate; benzophenone; benzyl.

As the radical polymerization initiator or the photopolymerization initiator, one kind or two or more kinds may be selected from these and used. The amount of the polymerization initiator used is 100 parts by weight of the total amount of the vinyl monomer component (weight. Part, the same applies hereinafter), preferably about 0.001 to 5 parts, especially about 0.01 to 2 parts.

In the present invention, when molding a water-containing soft contact lens, for example, a processing method (mechanical processing method) by cutting / polishing, a molding method using a die, which is usually carried out by those skilled in the art, Molding method) or a method combining a molding method and a mechanical processing method can be adopted.

In the mechanical processing method, after the vinyl monomer component and the cellulose derivative are made compatible with each other, the vinyl monomer component is subjected to cross-linking polymerization in a suitable mold or container to obtain a rod-shaped, block-shaped or plate-shaped material. It is a method of making a desired soft contact lens shape by subjecting it to mechanical processing such as cutting and polishing.

In the molding method, the vinyl monomer component and the cellulose derivative are made compatible with each other in a mold having a shape corresponding to the desired shape of the soft contact lens, and then the vinyl monomer component is crosslinked and polymerized. This is a method for obtaining a soft contact lens, and the obtained soft contact lens is mechanically finished as necessary.

In the method of combining the molding method and the mechanical processing method, first, a mold having a shape corresponding to at least one surface of the shape of the desired soft contact lens is prepared,
In this mold, the vinyl monomer component and the cellulose derivative are made compatible with each other, and the vinyl monomer component is cross-linked and polymerized,
Then, if necessary, mechanical processing is performed to obtain a soft contact lens.

According to the manufacturing method of the present invention, a water-containing soft contact lens can be easily manufactured in a short time and at low cost. In particular, the above-mentioned molding method and the combination of the molding method and the mechanical processing method are used. Compared with the mechanical processing method only, this method requires less vinyl monomer component and cellulose derivative as raw materials, lowers costs, requires less manufacturing process, and requires cross-linking polymerization. It has the advantages that the time is short and it is extremely easy to continuously mass-produce hydrous soft contact lenses.

Further, for example, a molded product obtained by the mechanical processing method, the molding method or a combination of both methods is immersed in water and boiled for about 5 to 30 minutes, and then physiological saline (0 A hydrated soft contact lens that is safe for living organisms can be obtained by subjecting it to boiling treatment for about 5 to 120 minutes in a (9% sodium chloride aqueous solution).

The hydrous soft contact lens of the present invention usually has a high water content of about 50 to 95% by weight, and further has appropriate strength as a hydrous soft contact lens and is excellent in transparency. It is a thing.

Next, the water-containing soft contact lens of the present invention and the method for producing the same will be described in more detail based on examples, but the present invention is not limited to these examples.

Examples 1 to 4 The cellulose derivatives shown in Table 1 (hereinafter referred to as HPC) were placed in a 100 ml Erlenmeyer flask so as to have the compositions shown in Table 2.
, N as hydrophilic (meth) acrylamide, N
-Dimethylacrylamide (hereinafter, referred to as DMAA) and ethylene glycol dimethacrylate (hereinafter, referred to as EDMA) as a crosslinkable vinyl monomer were added and mixed sufficiently to make HPC and DMAA compatible with each other, and benzoyl peroxide as a polymerization initiator. (Hereafter, BPO
) Was added and mixed rapidly by stirring.

In Example 4, methyl methacrylate (hereinafter referred to as MMA) as a hydrophobic vinyl monomer was added together with DMAA to make HPC compatible with DMAA and MMA.

Also, HPC and DMAA (and MMA)
Whether or not and were compatible was observed by visually observing the mixed solution and examined by whether or not it was transparent (cloud point method). As a result, in Examples 1 to 4, both HPC and DM
It was confirmed that AA (and MMA) were compatible with each other.

Next, this mixed solution was transferred into a press machine in which two polyester films were placed at intervals of 0.1 mm and polymerized at 130 ° C. for 10 minutes.

The obtained film polymer was dipped in 50 ml of water to swell with water, and then boiled for 30 minutes to remove unreacted monomers. After further exchanging water and performing the boiling treatment twice, the water was exchanged with the same amount of physiological saline and boiled for 30 minutes to obtain a water-containing film.

When the obtained films were pulled by hand and the feeling of strength was confirmed, the films obtained in any of the examples had appropriate strength as a water-containing soft contact lens. .

As the physical properties of the obtained film, water content, visible light transmittance and shape stability were examined according to the following methods. The results are shown in Table 2.

(A) Water content A film having a thickness of 0.2 mm when water is contained is 15 mm × 15.
The test piece obtained by cutting into a size of mm is stored in physiological saline at 20 ° C. for 120 minutes or more, and then water droplets on the surface of the test piece are quickly wiped to obtain a weight (W (g)) when water is contained.
Was measured. Next, this test piece was dried at 60 ° C. for 12 hours and then allowed to cool at room temperature to give a weight (Wo) when dried.
(G)) was measured and the water content (% by weight) was calculated based on the following formula.

Moisture content (% by weight) = {(W-Wo) / W} × 100 (b) Visible light transmittance Autograph spectrophotometer (UV-240 manufactured by Shimadzu Corporation)
Was used to measure the visible light transmittance (%) in the wavelength range of 780 to 380 nm. The film used had a thickness of 0.2 mm when it contained water, and the measurement was performed in water.

(C) Shape stability A test piece obtained by cutting a film having a thickness of 0.2 mm when hydrated at 20 ° C. into a size of 16 mm in diameter was used in physiological saline at 120 ° C. at 120 ° C. After boiling for a period of time, the diameter (Z (mm)) of the test piece was measured, and the dimensional change rate (%) was calculated based on the following formula to evaluate the shape stability. The dimensional change rate in the table is an average value for five test pieces.

Dimensional change rate (%) = {(Z−16) / 16} × 100 H shown by the abbreviations in Table 2 and Tables 3 to 4 below.
The PC is as shown in Table 1 below.

Further, in Table 2, DMAA (and MM
The ratio (% by weight) of the weight of EDMA to the weight of A) is also shown.

[0078]

[Table 1]

[0079]

[Table 2]

From the results shown in Table 2, each of the films obtained in Examples 1 to 4 had a high water content of about 80 to 90% by weight, a high visible light transmittance, and a high transparency. It can be seen that, in addition to being excellent, the dimensional change rate is less than 1%, and the shape stability is also excellent.

Examples 5 to 13 HPC, DMAA and EDMA shown in Table 1 were added to a 100 ml Erlenmeyer flask so as to have the composition shown in Table 3.
, HPC and DMAA were made to be compatible with each other, BPO was added as a polymerization initiator, and the mixture was rapidly stirred and mixed. Then, as a polyfunctional compound, polyisocyanate (Coronate HX, hereinafter referred to as HX)
Was added and mixed.

In Example 7, n-butyl methacrylate (hereinafter referred to as BMA) as a hydrophobic vinyl monomer was added together with DMAA, and in Examples 8 and 9, MMA was added together with DMAA to prepare HPC and DPC.
MAA and hydrophobic vinyl monomer were compatibilized.

Further, whether or not HPC and DMAA (and the hydrophobic vinyl monomer) are compatible with each other was examined in the same manner as in Example 1. In Examples 5 to 13, HPC and DMAA ( And hydrophobic vinyl monomer) were confirmed to be compatible with each other.

Next, using the obtained mixed solution, a film-like polymer was obtained in the same manner as in Example 1, and then a water-containing film was produced.

When the obtained films were pulled by hand and the feeling of strength was confirmed, the films obtained in any of the examples had appropriate strength as a water-containing soft contact lens. .

Further, the physical properties of the obtained film were evaluated in Example 1.
I examined it in the same way. Table 3 shows the results.

In Table 3, the ratio of the weight of EDMA to the weight of DMAA (and the hydrophobic vinyl monomer) (% by weight), and the equivalent ratio of the hydroxyl group in HPC to the isocyanate group in HX (hydroxyl group / hydroxyl group / Isocyanate group)
Are also shown.

[0088]

[Table 3]

From the results shown in Table 3, Examples 5 to 13
Each of the obtained films has a high water content of about 67 to 83% by weight, has a high visible light transmittance, is excellent in transparency, and has a dimensional change rate of less than 1%, and is stable in shape. It turns out that it is excellent.

Examples 14 to 17 The HPC shown in Table 1 was used in a 100 ml Erlenmeyer flask so that the composition shown in Table 4 was obtained, and dimethyl sulfoxide (hereinafter referred to as DMSO) as a solvent, DMAA and E.
DMA was added and thoroughly mixed to make HPC and DMSO and DMAA compatible with each other, azobisisobutyronitrile (hereinafter referred to as AIBN) was added as a polymerization initiator, and the mixture was rapidly stirred and mixed. Then HX was added and mixed.

In Example 17, MMA was added together with DMAA to prepare HPC, DMSO and DMAA.
And MMA.

Further, whether or not HPC was compatible with DMSO and the vinyl monomer component was examined in the same manner as in Example 1. In Examples 14 to 17, HPC, DMSO and the vinyl monomer component were all found. It was confirmed that and were compatible with each other.

Next, this mixed solution was transferred into a press machine in which two polyester films were placed at intervals of 0.1 mm and polymerized at 100 ° C. for 5 minutes.

The film-like polymer containing the obtained solvent was immersed in 500 ml of water to replace the solvent with water, and then immersed in 50 ml of water and boiled for 30 minutes to unreacted monomer and residual solvent. Was removed. After further exchanging water and performing the boiling treatment twice, the water was exchanged with the same amount of physiological saline and boiled for 30 minutes to obtain a water-containing film.

When the obtained films were pulled by hand and the feeling of strength was confirmed, the films obtained in any of the examples had appropriate strength as a water-containing soft contact lens. .

Further, the physical properties of the obtained film were evaluated in Example 1.
I examined it in the same way. The results are shown in Table 4.

In Table 4, DMAA (and MM
Ratio of the weight of EDMA to the weight of A) (wt%),
Also, the equivalent ratio (hydroxyl group / isocyanate group) between the hydroxyl group in HPC and the isocyanate group in HX is shown together.

[0098]

[Table 4]

From the results shown in Table 4, Examples 14 to 1
In Example 7, DMSO was used as a solvent, but all of the films obtained in Examples 14 to 17 had about 8%.
It has a high water content of 8 to 95% by weight, has a high visible light transmittance, is excellent in transparency, and has a dimensional change rate of less than 1%, and is also excellent in shape stability. .

Example 18 In Example 7, 0.6 part of AIBN was used as a polymerization initiator instead of 0.6 part of BPO, and 4 parts of polyisocyanate (Coronate HK) was used as a polyfunctional compound instead of 2 parts of HX. ED as a crosslinkable vinyl monomer
A mixed solution was obtained in the same manner as in Example 7 except that 0.8 part of 1,4-butanediol dimethacrylate was used instead of 0.6 part of MA.

The equivalent ratio of hydroxyl groups in HPC to isocyanate groups in HK (hydroxyl group / isocyanate group) is 20/1.

Further, whether or not HPC was compatible with DMAA and BMA was examined in the same manner as in Example 1, and it was confirmed that HPC was compatible with DMAA and BMA.

Next, this mixed solution was prepared in advance with 10
It was injected into a set of two molds having a shape corresponding to the shape of the soft contact lens preheated to 0 ° C., and polymerized at 100 ° C. for 5 minutes.

After the polymerization was completed, the mold was immersed in water and boiled for about 15 minutes, the mold was opened, and a transparent hydrous soft contact lens swollen with water was obtained.

The obtained hydrous soft contact lens was pulled by hand and the feeling of strength was confirmed. As a result, it was found that the hydrous soft contact lens had an appropriate strength.

Comparative Example 1 5 g of hydroxyethyl cellulose having a viscosity of about 6500 cP at 20 ° C. at 20 ° C. and a hydroxyethoxyl group content of 41% by weight in one molecule and 10 g of DMAA were mixed at room temperature (25 ° C.), and 30 After stirring for a minute, hydroxyethyl cellulose and DMAA were not compatible with each other.

Next, the mixture of hydroxyethyl cellulose and DMAA was heated at 90 ° C. for 1 hour, but again they could not be made compatible with each other.

From the results of Comparative Example 1, when hydroxyethyl cellulose was used, the hydrophilic vinyl monomer could not be made compatible with each other, the transparency as obtained by the production method of the present invention was excellent, and a suitable amount was obtained. It can be seen that it is difficult to obtain a highly hydrous soft contact lens having strength and excellent shape stability.

[0109]

EFFECT OF THE INVENTION The hydrous soft contact lens of the present invention has a high hydrous content, is excellent in transparency, and has appropriate strength as a hydrous soft contact lens, and is also stable in shape. It is excellent.

Further, according to the manufacturing method of the present invention, since the hydrous soft contact lens can be easily produced in a short time, the cost can be reduced, and the hydrous soft contact lens, especially the disposable type, can be manufactured at a high cost. The effect that continuous mass production of hydrous soft contact lenses is possible is exhibited.

Claims (15)

[Claims] 1. A polymer obtained by crosslinking and polymerizing a vinyl monomer component containing hydrophilic (meth) acrylamide, and the content of hydroxypropoxyl groups in one molecule is 3.
A hydrous soft contact lens comprising ˜75% by weight of a cellulose derivative. 2. The hydrous soft contact lens according to claim 1, wherein the vinyl monomer component and the cellulose derivative are compatible with each other, and the vinyl monomer component is cross-linked and polymerized. 3. A vinyl monomer component containing hydrophilic (meth) acrylamide and a cellulose derivative having a hydroxypropoxyl group content in one molecule of 3 to 75% by weight are made compatible with each other, and the vinyl monomer component is A method for producing a water-containing soft contact lens, which comprises cross-linking polymerization. 4. The method for producing a hydrous soft contact lens according to claim 3, wherein the hydrophilic (meth) acrylamide is a dialkyl (meth) acrylamide. 5. The method for producing a hydrous soft contact lens according to claim 3, wherein the vinyl monomer component contains 40% by weight or more of hydrophilic (meth) acrylamide. 6. The method for producing a water-containing soft contact lens according to claim 3, wherein the vinyl monomer component contains a hydrophobic vinyl monomer. 7. The method for producing a water-containing soft contact lens according to claim 6, wherein the hydrophobic vinyl monomer is an alkyl (meth) acrylate. 8. The method for producing a hydrous soft contact lens according to claim 6, wherein the vinyl monomer component contains 60% by weight or less of a hydrophobic vinyl monomer. 9. A weight ratio of a vinyl monomer component and a cellulose derivative (vinyl monomer component / cellulose derivative).
Is 15 / 85-95 / 5.
7. The method for producing a water-containing soft contact lens according to 7 or 8. 10. A cross-linking vinyl monomer is used to cross-link and polymerize a vinyl monomer component.
7. A method for producing a hydrous soft contact lens according to 7, 8 or 9. 11. The method for producing a water-containing soft contact lens according to claim 10, wherein the content of the crosslinkable vinyl monomer is 0.01 to 10% by weight based on the total weight of the vinyl monomer component. 12. The cross-linking polymerization of a vinyl monomer component while cross-linking cellulose derivatives with each other.
The method for producing a water-containing soft contact lens according to 4, 5, 6, 7, 8, 9, 10 or 11. 13. The method for producing a hydrous soft contact lens according to claim 12, wherein the cellulose derivative is crosslinked with a polyfunctional compound capable of crosslinking with the cellulose derivative. 14. The method for producing a hydrous soft contact lens according to claim 13, wherein the polyfunctional compound capable of crosslinking with the cellulose derivative is polyisocyanate. 15. The vinyl monomer component is cross-linked and polymerized in a mold having a shape corresponding to the shape of the soft contact lens.
The method for producing a water-containing soft contact lens according to 1, 12, 13 or 14.