JPH05295143A - Production of contact lens - Google Patents

Abstract

PURPOSE:To obtain the lens which is completely freed from unreacted monomer and is nontoxic by subjecting a contact lens base made from a specified polymer to specified treatments. CONSTITUTION:The surface of a contact lens made from a methacrylic copolymer essentially consisting of an alkyl methacrylate (e.g. methyl methacrylate) and a siloxanyl methacrylate of formula I (wherein X and Y are each a 1-5C alkyl or a group of formula II; a is a 1-5C alkyl; and k, l, m and n are each 0 or greater) is subjected to a discharge treatment at atmospheric pressure or in a vacuum. A hydrophilic monomer (e.g. acrylamide) is grafted onto this surface, and the grafted base is immersed in a solvent, desirably water at 20 deg.C or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for obtaining a hard contact lens which maintains the wettability of the surface permanently and is excellent in wearing feeling.

[0002]

2. Description of the Related Art In order to reduce the foreign body sensation when wearing a contact lens and improve the wearing sensation, it is important to improve the conformity between the cornea and the lens surface. As a specific method, it is possible to improve the wettability of the lens surface by graft-polymerizing a hydrophilic monomer on the surface of the contact lens. The surface graft polymerization treatment process will be briefly described. First, a contact lens substrate that has been subjected to discharge treatment or the like is immersed in a monomer solution. Next, dissolved oxygen is removed, and then the surface is subjected to surface graft polymerization treatment by heating it.

[0003]

However, in the above-mentioned prior art, the unpolymerized monomer component remains on the surface of the lens substrate, and the residual monomer causes irritation to the eye during wearing of a contact lens or the cornea. Turbidity, conjunctival congestion,
In the worst case, it had the problem of leading to blindness.

Therefore, the present invention is to solve such a conventional problem, and an object of the present invention is to prevent a monomer which is an unpolymerized reaction product from remaining on the lens surface after surface graft polymerization. It is to provide a method of manufacturing a contact lens that is completely non-toxic.

[0005]

In order to solve the above-mentioned problems, the method for producing a contact lens according to the present invention comprises at least an alkyl methacrylate and a siloxanyl methacrylate (

[0006]

[Chemical 3]

Wherein X and Y are selected from the group consisting of C ₁ -C ₅ alkyl groups and groups, and Z is a structural formula

[0008]

[Chemical 4]

A represents a C ₁ -C ₅ alkyl group. k, l, m, and n represent 0 or a positive integer. (A) a contact lens substrate using as a raw material a polymer of a methacrylic acid ester compound which is a copolymer of (a) a step of subjecting the surface to an electric discharge treatment under normal pressure or a reduced pressure; The method is characterized by comprising a step of graft-polymerizing a hydrophilic monomer with and a step of immersing (c) the grafted substrate in a solvent. Further, the solvent in the step (c) is water.
The temperature of this water is 20 ° C. or higher.

The following are typical ester compounds of methacrylic acid. Pentamethyldisiloxanyl methyl methacrylate

[0011]

[Chemical 5]

Tris (trimethylsiloxy) -γ-methacryloxypropylsilane

[0013]

[Chemical 6]

Isobutyl hexamethyl trisiloxanyl methyl methacrylate

[0015]

[Chemical 7]

The present invention will be described in detail below with reference to examples.

[0017]

【Example】

(Example 1) 10 g of acrylamide was dissolved in distilled water to 100 ml to prepare a monomer aqueous solution.

Graft polymerization was carried out as follows.
Methyl methacrylate 60 wt%, tris (trimethylsiloxy) silylpropyl methacrylate 35 wt%,
A contact lens substrate made of a copolymer of 2-hydroxyethyl methacrylate 5 wt% was prepared.

The lens substrate was placed in a discharge device (6 cm between electrodes, voltage between electrodes 270 V, frequency 60 Hz), and glow discharge treatment was performed for 5 seconds in an argon atmosphere of 0.04 torr. After exposing the lens base material subjected to the electric discharge to the air, the lens base material was put into a test tube, and the monomer aqueous solution was added in such an amount that the lens base material was sufficiently immersed. This was connected to a vacuum system, the inside of the tube was degassed, and the tube was vacuum sealed as it was. In this state, the test tube was inserted into a reciprocal shaker (EP-1, manufactured by Taiyo Service Center Co., Ltd.) and subjected to a graft polymerization treatment on the surface of the base material for 60 minutes at a constant temperature of 80 ° C. while shaking. After the completion of the polymerization, the lens was taken out, immersed in pure water set to a predetermined temperature, and rinsed for 3 hours. The temperature was set as shown in Table 1, and 1 gram (about 100 lenses) of contact lens was used for each temperature (Sample 1
~ 8). On the other hand, for comparison, the surface-grafted contact lens according to the conventional method, that is, the method without the above-mentioned rinsing step with pure water is 1 gram (about 100 g).
(Comparative example 1). The monomer (here, acrylamide) remaining on the lens surface was quantified by the method described below.

Sufficiently dried contact lenses were crushed with a hammer, passed through a 50-mesh sieve to recover exactly 1 gram, and placed in a glass bottle. To this, 50 ml of pure water was added and kept at 100 ° C for 30 minutes in an autoclave. After taking out from the autoclave and cooling to room temperature, a supernatant liquid was collected and subjected to analysis by liquid chromatography.

Table 1 shows the peak heights of acrylamide obtained for Samples 1 to 8 and Comparative Example 1. Here, the peak height represents a relative value with that for Comparative Example 1 being 1.0. As is clear from Table 1, in Comparative Example 1, that is, the conventional method, the largest amount of acrylamide monomer was detected as a result of the analysis. On the other hand, in the samples according to the present invention (Samples 1 to 8), almost no acrylamide monomer was detected, and especially in Samples 3 to 8, that is, when the temperature of pure water was 20 ° C. or higher in the rinse step with pure water, 3 hours It was revealed that the acrylamide monomer was completely removed from the surface of the lens by the immersion.

In this embodiment, pure water was used as the solvent in the rinsing step, but the solvent is not limited to this, and any solvent having a certain degree of solubility in the monomer may be used.

[0023]

[Table 1]

Example 2 10 g of acrylamide was dissolved in distilled water to 100 ml to prepare an aqueous monomer solution.

Graft polymerization was carried out as follows.
Methyl methacrylate 60 wt%, tris (trimethylsiloxy) silylpropyl methacrylate 35 wt%,
A contact lens substrate made of a copolymer of 2-hydroxyethyl methacrylate 5 wt% was prepared.

A space made of a spacer having a thickness of 1.5 mm is provided between the electrodes of a corona discharge treatment device having a distance between the electrodes of 3.5 cm, a voltage between the electrodes of 15 kV, and a frequency of 60 hertz. Install the material,
Discharge treatment was performed. It should be noted that discharge treatment was performed on one side and on both sides for 40 seconds. Next, this discharge-treated lens substrate was put into a test tube, and the monomer aqueous solution was added in such an amount that the lens substrate was sufficiently immersed. This was connected to a vacuum system, the inside of the tube was degassed, and the tube was vacuum sealed. In this state, the test tube was inserted into a reciprocal shaker (EP-1, manufactured by Taiyo Service Center Co., Ltd.) and subjected to a graft polymerization treatment on the surface of the base material for 60 minutes at a constant temperature of 80 ° C. while shaking.

After the completion of the polymerization, the lens was taken out, immersed in pure water set to a predetermined temperature, and rinsed for 3 hours. The temperature was set as shown in Table 2, and 1 gram (about 100 lenses) of contact lens was used for each temperature (Samples 1 to 1).
8). On the other hand, for comparison, the surface-grafted contact lens according to the conventional method, that is, the method without the above-mentioned rinsing step with pure water is 1 gram (about 100 g).
(Comparative example 1).

The monomer (here, acrylamide) remaining on the lens surface was quantified by the following method.

A sufficiently dried contact lens was crushed with a hammer, passed through a 50-mesh sieve to recover exactly 1 gram, and placed in a glass bottle. To this, 50 ml of pure water was added and kept at 100 ° C for 30 minutes in an autoclave. After taking out from the autoclave and cooling to room temperature, a supernatant liquid was collected and subjected to analysis by liquid chromatography.

Table 2 shows the peak heights of acrylamide obtained for Samples 1 to 8 and Comparative Example 1. Here, the peak height represents a relative value with that for Comparative Example 1 being 1.0.

As is clear from Table 2, in Comparative Example 1, that is, the conventional method, the largest amount of acrylamide monomer was detected as a result of the analysis. On the other hand, in the samples according to the present invention (Samples 1 to 8), almost no acrylamide monomer was detected, and particularly in Samples 3 to 8, that is, when the pure water temperature was 20 ° C. or higher in the rinse step with pure water.
It was revealed that the acrylamide monomer was completely removed from the lens surface by immersion for a time.

In this embodiment, pure water was used as the solvent in the rinsing step, but the solvent is not limited to this, and any solvent having a certain degree of solubility in the monomer may be used.

[0033]

[Table 2]

In the embodiment of the present invention, a Si-based PMM is used.
Although the description has been made using the contact lens made by A, the same result is obtained not only for this but also for other hard contact lenses and soft contact lenses such as silicon rubber.

Further, similar results were obtained for surface treatment of polyethylene film, polypropylene, polyvinyl chloride, polyvinylidene chloride, acetate, polyester, polyvinyl alcohol, polystyrene, polycarbonate, polyurethane and various other polymeric materials. ..

In addition, it can be applied to various packaging materials using the above-mentioned materials, agricultural water retention materials, or medical products such as artificial organs.

[0037]

According to the present invention, since the surface graft polymerization treatment is followed by the rinse treatment in a solvent, the monomer which is an unpolymerized reaction product does not remain on the surface of the contact lens and it is completely non-toxic. You can get contact lenses.

Claims (3)

[Claims] 1. At least an alkyl methacrylate,
Siloxanyl methacrylate (Chemical formula 1) Where X and Y are selected from the group consisting of C ₁ -C ₅ alkyl groups and Z groups, where Z is a structural formula And A represents a C _{1 to} C ₅ alkyl group.
k, l, m, and n represent 0 or a positive integer. (A) a contact lens substrate using as a raw material a polymer of an ester compound of methacrylic acid which is a copolymer with (a) a step of subjecting the surface to an electric discharge treatment under normal pressure or reduced pressure;
A method for producing a contact lens, comprising (b) a step of graft-polymerizing a hydrophilic monomer on the surface of the base material, and (c) a step of immersing the grafted base material in a solvent. 2. The method for producing a contact lens according to claim 1, wherein the solvent in the step (c) is water. 3. The method for manufacturing a contact lens according to claim 2, wherein the water temperature is 20 ° C. or higher.