JPH0467011A - Contact lens manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to contact lenses, and particularly to hard contact lenses that are excellent in wettability and wear comfort.

[Prior Art] In order to reduce the feeling of a foreign body when wearing a contact lens and improve the feeling of wearing it, it is important to improve the compatibility 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, onto the surface of the contact lens. Conventionally, graft polymerization has been carried out by bringing only acrylamide monomer into contact with a contact lens base material.

[Problem M to be solved by the invention] However, in the above-mentioned conventional technology, the adhesion strength between the graft polymer and the lens base material is low, and the graft polymer peels off when rubbed with fingers, resulting in poor wettability before grafting. It had the disadvantage of returning. Therefore, the present invention is intended to solve this problem, and its purpose is to provide a method for manufacturing contact lenses with high wear resistance that improves the adhesion strength between the lens base material and the graft polymer. be.

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a contact lens of the present invention includes: (a) at least alkyl methacrylate and siloxanyl methacrylate in which X and Y are C;
selected from the group consisting of a 1-C5 alkyl group and a Z group, Z is a group having a structural formula, and A represents an 01-C5 alkyl group.

m and n are 0. Or indicates a positive integer. (b) Graft polymerization of acrylamide onto the lens surface in a contact lens base material made from a polymer of an ester compound of methacrylic acid, which is a copolymer with A method for manufacturing a contact lens comprising the steps of (b) adding a crosslinking agent to the aqueous acrylamide monomer solution in step (b).

In addition, the following are listed as typical ester compounds of methacrylic acid.

Pentamethyldisiloxanyl methyl methacrylate Isobutyl hexamethyltrisiloxanyl methyl methacrylate Tris(trimethylsiloxy)-γ-methacryloxypropylsilane Show details.

[Example 1] Crosslinking agent N,N'-methylenebisacrylamide 2
．． Dissolve 5g and 10g of acrylamide in water for 100m
1, and an aqueous monomer solution was prepared.

Graft polymerization was carried out as follows. A contact lens base material made of a copolymer of 60 wt% methyl methacrylate, 35 wt% tris(trimethylsiloxy)silylpropyl methacrylate, and 5 wt% 2-hydroxyethyl methacrylate was prepared. The lens base material was placed in a discharge device (electrode spacing 6 cm, interelectrode voltage 270 volts, frequency 60 hertz), and glow discharge treatment was performed for 5 seconds in an argon atmosphere of 0.041 mm. After exposing the discharge-treated lens base material to the air, it was placed in a test tube, a crosslinking agent-added acrylamide monomer aqueous solution was added, the tube was replaced with nitrogen gas, and the tube was sealed under reduced pressure. The test tube was placed in a constant temperature bath at 80° C. for 60 minutes, and acrylamide was graft-polymerized on the surface of the lens base material (Samples Nos. 011 to 6). In addition, for comparison with the conventional method, a sample was prepared using a 10 wt % acrylamide monomer aqueous solution to which no crosslinking agent was added. (Comparative Examples 1 to 6) The polymerization conditions at this time were exactly the same as those for the samples with the addition of a crosslinking agent. In addition, the treated lenses were rubbed 1,000 times with the palm of the hand sprinkled with detergent to perform an abrasion resistance test. Graft polymer peeling was evaluated by examining the change in contact angle between the lens surface before and after rubbing. The contact angle was measured by the dripping method, and water was used as the solvent. These results are listed in Table 1.

Table 1 Methyl methacrylate 60 wt%, tris(trimethylsiloxy)silylpropyl methacrylate 35 wt%,
A contact lens base material made of a copolymer of 5 wt% 2-hydroxyethyl methacryate was prepared. Interelectrode path 93. This lens base material was placed in a space created by a 1.5 mm thick spacer between the electrodes of a corona discharge treatment device with a diameter of 5 cm, an interelectrode voltage of 15 kilovolts, and a frequency of 60 Hz, and discharge treatment was performed. Incidentally, discharge treatment was applied to one side and both sides for 40 seconds each. Next, this discharge-treated lens base material was placed in a test tube, and the same crosslinking agent-added acrylamide monomer aqueous solution as used in Example 1 was added thereto, and the tube was sealed under reduced pressure after purging with nitrogen gas. 8 test tubes
The lenses were placed in a constant temperature bath at 0° C. for 60 minutes to graft-polymerize acrylamide onto the surface of the lens base material (Samples Nos. 1 to 6).

In addition, for comparison with the conventional method, 10 wt without crosslinking agent was added.
% acrylamide aqueous solution was prepared.

(Comparative Examples 1 to 6) The polymerization conditions at this time were exactly the same as those for the samples in which a crosslinking agent was added. In addition, the treated lenses were rubbed 1,000 times with the palm of the hand sprinkled with detergent to perform an abrasion resistance test. Graft polymer peeling was evaluated by examining the change in contact angle between the lens surface before and after rubbing. The contact angle was measured by the dripping method, and water was used as the solvent.

These results are listed in Table 2.

As is clear from the second slope of Table 2, the increase in the contact angle after rubbing was significantly suppressed by adding the crosslinking agent, and the water wettability of the lens surface was maintained. That is,
By crosslinking the acrylamide polymer with N,N-methylenebisacrylamide, the adhesion strength between the lens base material and the graft polymer was increased, and the abrasion resistance of the graft lens surface was able to be improved.

Although the embodiments of the present invention have been explained using Si-based PMMA contact lenses, the present invention is not limited thereto, and is not limited to polyethylene films, polypropylene, polyvinyl chloride,
Polyvinylidene chloride, acetate, polyester, polyvinyl alcohol, polystyrene, polycarbonate,
Similar results were obtained for surface treatments of various other plastic films. Furthermore, the above-mentioned trees can be used in various packaging materials, agricultural water retaining materials, and medical products such as artificial organs.

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

[Effects of the Invention] As described above, according to the invention, by adding N,N'-methylenebisacrylamide to the acrylamide monomer aqueous solution that is the polymerization system, the grafted polymer takes on a crosslinked structure and forms a lens base material. The adhesion strength has been strengthened and wear resistance has been dramatically improved. This has the effect that the water wettability of the contact lens can be maintained for a long period of time.

Therefore, the present invention can be said to be a very effective method for producing contact lenses that are comfortable to wear.

that's all Applicant: Seiko Epson Corporation

Claims (1)

[Claims] (a) At least alkyl methacrylate and siloxanyl methacrylate (▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, X and Y are C_1 to C_5 alkyl groups and Z
is selected from the group consisting of groups, Z is a group having the structural formula ▲ Numerical formula, chemical formula, table, etc. ▼, and A represents an alkyl group of C_1 to C_5. m and n represent 0 or a positive integer. (b) Graft polymerization of acrylamide onto the lens surface in a contact lens base material made from a polymer of a methacrylic acid ester compound, which is a copolymer with A method for producing a contact lens comprising the step of (b) adding a crosslinking agent to the aqueous acrylamide monomer solution in step (b).