JP2745771B2 - 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.

[Prior art] As a means for reducing the feeling of foreign matter when wearing a contact lens and improving the feeling of wearing, a hydrophilic monomer is graft-polymerized on the surface of the contact lens to improve wettability and to improve the corneal and lens surfaces. There are ways to improve familiarity. First, the lens is subjected to discharge treatment to generate radicals on the surface, and the peroxide is introduced by exposing it to the atmosphere. Thereafter, the lens is immersed in an aqueous acrylamide monomer solution to start graft polymerization. In order for the polymerization to start, it is necessary that the peroxide introduced to the surface decomposes, that is, acts as a polymerization initiator. That is, in order to carry out the polymerization, the energy required for peroxide decomposition must be supplied. Conventionally, at the start of polymerization, a thermal polymerization method of heating an aqueous monomer solution at a high temperature of 50 ° C. or higher has been employed.

[Problem to be Solved by the Invention] However, the above-described conventional technology has a disadvantage that the lens is placed in a harsh environment of high heat. In making contact lenses, advanced processing techniques are used, and rigorous inspections are performed to ensure thoroughness. Therefore, the present invention solves this problem, and an object of the present invention is to provide a method for producing a contact lens that enables graft polymerization at a low temperature.

[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 (1) 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. And (2) graft polymerization of acrylamide onto the lens surface of a contact lens substrate made from a polymer of an ester compound of methacrylic acid, which is a copolymer of A contact lens manufacturing method, characterized in that the step (2) is performed at a low temperature by adding ferrous ammonium sulfate (Mole salt) to an aqueous acrylamide solution.

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] An aqueous solution of acrylamide with a Mohr salt was prepared as follows. First, ferrous ammonium sulfate hexahydrate 0.07
84 g was weighed, dissolved in a 10 wt% acrylamide aqueous solution prepared in advance, and made up to 20 ml.

The graft polymerization was performed as follows. A contact lens substrate composed of a copolymer of methyl methacrylate 60% by weight, tris (tomimethylsiloxy) silylpropyl methacrylate 35% by weight, and 2-hydroxyethyl methacrylate 5% by weight was prepared, and the lens curvature before the graft treatment was measured. 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. After the discharge-treated lens substrate was taken out into the air, it was put into a test tube, an aqueous solution of acrylamide with Mohr's salt was added thereto, and the atmosphere was replaced with nitrogen gas. Test tube at 30 ℃
Was placed in a constant temperature bath for 60 minutes, and acrylamide was graft-polymerized on the surface of the lens substrate (Sample Nos. 1 to 6). For comparison with the conventional method, a sample was prepared by a thermal polymerization method using a 10 wt% acrylamide aqueous solution without addition of Mohr's salt. (Comparative Examples 1 to 6) At this time, the polymerization temperature was set to 80 ° C., and the polymerization time was set to 20 minutes. In addition, the lens curvature after the treatment was measured. The contact angle with water was measured by a droplet method, and the amount of acrylamide grafted was quantified by a ninhydrin method. The results are listed in Table 1.

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, and the lens curvature before the grafting treatment was measured. did. 3.5 cm between electrodes,
This lens substrate was placed in a space made of 1.5 mm thick spacers between the electrodes of a corona discharge treatment device with a voltage between electrodes of 15 kV and a frequency of 60 Hz, and discharge treatment was performed. In addition, discharge treatment was performed on each side and each side for 40 seconds. Next, the discharge-treated lens substrate is placed in a test tube,
The same aqueous solution of acrylamide with a Mohr salt as used in Example 1 was added thereto, and the atmosphere was replaced with nitrogen gas. The test tube was placed in a thermostat at 30 ° C for 60 minutes, and acrylamide was graft-polymerized on the surface of the lens substrate (Sample Nos. 1 to 4).
6). For comparison with the conventional method,
A sample was prepared by a thermal polymerization method using a 10 wt% acrylamide aqueous solution. (Comparative Examples 1 to 6) The polymerization temperature at this time was 80
C., the polymerization time was set to 20 minutes, and the discharge conditions and the like were exactly the same as those of the sample to which Mohr's salt was added. In addition, the lens curvature after the treatment was measured. The contact angle with water was measured by a droplet method, and the graft amount of acrylamide was quantified by a ninhydrin method. Table 2 shows the results.

As is clear from Tables 1 and 2, the change in the curvature of the lens is much smaller when the low-temperature treatment is performed by adding Mohr's salt. Moreover, the wettability and the amount of grafting were not inferior to those of the conventional thermal polymerization method.

Examples of the present invention have been described using a Si-based PMMA contact lens, but without being limited thereto, polyethylene film, polypropylene, polyvinyl chloride, polyvinylidene chloride, acetate, polyester, polyvinyl alcohol, polystyrene, polycarbonate Similar results were obtained for various other plastic film surface treatments. 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.

[Effects of the Invention] As described above, according to the invention, a low-temperature grafting treatment can be performed by adding a Mohr salt to an acrylamide aqueous solution. This has the effect that the lens can be released under harsh processing conditions. Therefore, from the viewpoint of protecting the base material, the present invention can be said to be a very effective method, but the effect brought by it is great.

Claims (2)

(57) [Claims] (1) at least an alkyl methacrylate, 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) a discharge treatment under normal pressure or reduced pressure on the surface of a contact lens substrate made from a polymer of an ester compound of methacrylic acid, which is a copolymer of the contact lens substrate; and acrylamide on the surface of the contact lens substrate. In the method for producing a contact lens comprising a second step of graft polymerization, the second step comprises adding ammonium ferrous sulfate (mole salt) to an aqueous acrylamide solution and grafting acrylamide onto the surface of the contact lens substrate at a low temperature. A method for producing a contact lens, comprising polymerizing. 2. The method of manufacturing a contact lens according to claim 1, wherein said second step comprises graft-polymerizing acrylamide onto the surface of said contact lens substrate at a low temperature of less than 50 ° C.