JP2995823B2 - Method of manufacturing contact lenses - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a contact lens, and more particularly to a hard contact lens excellent in wettability and wearing feeling.

[Related Art] In order to reduce the feeling of foreign matter when wearing a contact lens and to improve the wearing feeling, it is important to improve the familiarity between the cornea and the lens surface. A specific method is to improve the wettability of the lens surface by graft polymerizing acrylamide, which is a hydrophilic monomer, on the surface of the contact lens. Further, there is a method of improving abrasion resistance by crosslinking a graft chain in order to maintain wettability for a long period of time. Conventionally, it has been considered that the larger the amount of the crosslinking agent added, the more the effect of crosslinking can be improved, and the more the abrasion resistance of the graft chain can be improved.

[Problems to be Solved by the Invention] However, the above-described conventional technology has a disadvantage that the surface of the lens becomes cloudy and the transparency is deteriorated because light scattering occurs in the graft polymer layer on the lens. Therefore, the present invention solves this problem, and an object of the present invention is to provide a method for manufacturing a contact lens that maintains high wettability for a long period of time and is excellent in transparency.

[Means for Solving the Problems] In order to solve the above problems, the method for producing a contact lens according to the present invention comprises: (a) at least an alkyl methacrylate and a siloxanyl methacrylate ( Wherein X and Y are selected from the group consisting of C ₁ -C ₅ alkyl groups and Z groups; A group having, A is an alkyl group of C ₁ -C _5. m, n
Represents 0 or a positive integer. A) subjecting a contact lens substrate made of a polymer of an ester compound of methacrylic acid, which is a copolymer with the above, to a discharge treatment under normal pressure or reduced pressure, and (b) applying a hydrophilic monomer to the lens surface. A method of producing a contact lens, comprising: a step of graft-polymerizing the concentration of N, N′-methylenebisacrylamide in a monomer aqueous solution comprising at least acrylamide, N, N′-methylenebisacrylamide and water in the step (b). It is characterized by being 10 wt% or less.

The following are typical examples of methacrylic acid ester compounds.

Pentamethyldisiloxanylmethyl methacrylate Tris (trimethylsiloxy) -γ-methacryloxypropylsilane Isobutyl hexamethyltrisiloxanyl methyl methacrylate Hereinafter, the present invention will be described in detail with reference to examples.

[Example 1] A contact lens substrate comprising a copolymer of methyl methacrylate 60 wt%, tris (trimethylsiloxy) silylpropyl methacrylate 35 wt%, and 2-hydroxyethyl methacrylate 5 wt% was prepared. The lens substrate was placed in a discharge device (6 cm between electrodes, voltage between electrodes 270 volts, frequency 60 Hz), and glow discharge treatment was performed for 5 seconds in an argon atmosphere of 0.04 torr. The discharge-treated lens substrate was exposed to air and placed in a test tube.

Acrylamide and N, N'-methylenebisacrylamide were dissolved in water to obtain a monomer aqueous solution. At that time, the first
Six types of aqueous solutions in which the weight ratio of each component was changed according to the table were prepared. 2.5 ml of each aqueous solution was dispensed into a test tube so that the entire lens substrate was immersed in the monomer aqueous solution. After purging with nitrogen gas, the tube was sealed under reduced pressure. Test tubes in 80 ° C constant temperature bath
After 60 minutes, a monomer was graft-polymerized on the lens substrate surface (Sample Nos. 1 to 6).

For comparison with the conventional method, 10 wt%
Samples using an aqueous acrylamide monomer solution were prepared (Comparative Examples 1 to 6). The polymerization conditions at this time were as follows:
It was exactly the same as at the time.

Visible light (480nm) for the lens after grafting
Was measured to evaluate the degree of white turbidity of the lens.
The results are shown in Table 1.

Subsequently, a lens having high transmittance and no cloudiness (No. 1
Tables, the same as those of Sample Nos. 1 to 4) were subjected to tests for confirming wear resistance.

First, a 1000-round scrub was carried out with a detergent-coated palm. Next, the contact angle of the lens surface after rubbing was measured, and the degree of peeling of the graft polymer was evaluated by observing the difference from the contact angle before rubbing recorded in advance.

For comparison, a graft-treated product with a 10 wt% acrylamide aqueous solution system to which no crosslinking agent was added (Table 1, Comparative Examples 1 to 6)
The same operation as in Samples Nos. 1 to 4 was performed.

The measurement of the contact angle was performed by a droplet method, and water was used as a solvent. Table 2 shows the results.

[Example 2] A contact lens substrate made of a copolymer of methyl methacrylate 60 wt%, tris (trimethylsiloxy) silylpropyl methacrylate 35 wt%, and 2-hydroxyethyl methacrylate 5 wt% was prepared. This lens substrate is placed in a space made of spacers with a thickness of 1.5 mm between the electrodes of a corona discharge treatment device with a distance of 3.5 cm between electrodes, a voltage of 15 kV between electrodes, and a frequency of 60 Hz.
Discharge treatment was performed. In addition, discharge treatment was performed on each side and each side for 40 seconds.

Next, in the same manner as in Example 1, 2.5 ml of each of the monomer aqueous solutions having different component ratios was prepared in a test tube, and Mohr's salt (ammonium ferrous sulfate) as a redox catalyst was added to each and stirred to dissolve. The lens substrate subjected to the discharge treatment was put therein, and after nitrogen gas replacement, the tube was sealed under reduced pressure. Test tubes
The monomer was graft-polymerized on the surface of the lens substrate by placing it in a thermostat at 30 to 50 ° C. for 40 to 90 minutes (Sample Nos. 1 to 6).

For comparison, a sample using a 10 wt% acrylamide monomer aqueous solution without a crosslinking agent was prepared. (Comparative Examples 1 to 6) The polymerization conditions at this time were exactly the same as those for Samples Nos. 1 to 6.

Visible light (480nm) for the lens after grafting
Was measured to evaluate the degree of white turbidity of the lens.
The results are shown in Table 3.

Subsequently, a lens having high transmittance and no cloudiness (No. 1
Tables, the same as those of Sample Nos. 1 to 4) were subjected to tests for confirming wear resistance.

First, a 1000-round scrub was carried out with a detergent-coated palm. Next, the contact angle of the lens surface after rubbing was measured, and the degree of peeling of the graft polymer was evaluated by observing the difference from the contact angle before rubbing recorded in advance.

For comparison, a graft-treated product with a 10 wt% acrylamide aqueous solution system to which no crosslinking agent was added (Table 1, Comparative Examples 1 to 6)
The same operation as in Samples Nos. 1 to 4 was performed.

The measurement of the contact angle was performed by a droplet method, and water was used as a solvent. These results are listed in Table 4.

As is clear from Tables 1 and 3, at least:
In a polymerization solution composed of acrylamide, N, N'-methylenebisacrylamide, and water, those having 10% by weight or less of N, N'-methylenebisacrylamide (Samples 1 to 4) are excellent in transmission of visible light, and have excellent lens surface. Was not observed. Further, the value of the transmittance at this time was not inferior to the polymer (Comparative Examples 1 to 6) in a 10 wt% acrylamide aqueous solution system, and was a sufficiently satisfactory value as the transparency of the contact lens. On the other hand, when the amount of N, N'-methylenebisacrylamide exceeded 10% by weight (samples Nos. 5 and 6), the lens surface became cloudy, and the transmittance was greatly reduced.

As is clear from Tables 2 and 4, the increase in the contact angle after rubbing was caused by the addition of the crosslinking agent (Sample No. 1).
4) were significantly suppressed, and the water wettability of the lens surface was maintained. From these results, it was confirmed that the durability of the graft contact lens having no turbidity was sufficiently large and had commercial value.

As described above, a graft contact lens having high durability and having no cloudiness on the lens surface could be produced.

Although the embodiment of the present invention has been described using a Si-based PMMA contact lens, the present invention is not limited to this, and similar results are obtained with other hard contact lenses and soft contact lenses such as silicon rubber.

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

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

In addition, acrylates such as glycerin diacrylate and trimethylolpropane triacrylate as crosslinking agents, and methacrylates such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate. Similar results were obtained when used.

[Effects of the Invention] As described above, according to the invention, the amount of N, N'-methylenebisacrylamide added is limited as described in the claims, thereby improving the abrasion resistance of the graft chain, High wettability could be maintained for a long time.
Moreover, no surface turbidity was generated, and the original optical characteristics of the lens did not deteriorate. Therefore, it can be said that the present invention is very effective for the production of a contact lens excellent in wearing feeling.

Claims (1)

(57) [Claims] (1) At least (a) an alkyl methacrylate and a siloxanyl methacrylate ( Wherein X and Y are selected from the group consisting of C ₁ -C ₅ alkyl groups and Z groups; A group having, A is an alkyl group of C ₁ -C _5. m, n
Represents 0 or a positive integer. A) subjecting a contact lens substrate made of a polymer of an ester compound of methacrylic acid, which is a copolymer with the above, to a discharge treatment under normal pressure or reduced pressure, and (b) applying a hydrophilic monomer to the lens surface. A method of producing a contact lens, comprising: a step of graft-polymerizing the concentration of N, N′-methylenebisacrylamide in a monomer aqueous solution comprising at least acrylamide, N, N′-methylenebisacrylamide and water in the step (b). A method for producing a contact lens, characterized in that the content is 10 wt% or less.