JPH04178609A - Production of contact lens - Google Patents

Abstract

PURPOSE:To allow the uniform treatment of excellent reproducibility required at the time of mass production by regulating the time for impressing ultrasonic waves at the time of removing the dissolved oxygen in an aq. monomer soln. CONSTITUTION:The contact lens base material formed of the polymer of the ester compd. of methacrylic acid which is the copolymer of at least the alkyl methacrylate of formula I, siloxyanyl methacrylate and the methacrylate contg. the fluorine substituent of formula II is used. The time for impressing the ultrasonic waves is specified to 10 seconds to 10 minutes at the time of removing the dissolved oxygen in the aq. soln. consisting essentially of the acrylamide monomer by impressing the ultrasonic waves under vacuum to this aq. soln. in the process for producing the contact lens consisting of a stage for subjecting the surface of the above-mentioned contact lens base material to a discharge treatment under an atm. pressure or reduced pressure and a stage for graft polymerizing the acrylamide on the lens surface. In the formula, X and Y are selected from the group consisting of 1 to 5C alkyl group and the Z group of formula III; A denotes 1 to 5C alkyl group; k, l, m, n denote 0 or positive integer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a manufacturing method for obtaining a hard contact lens that permanently maintains surface wettability and is comfortable to wear.

[Conventional technology]

In order to reduce the foreign body sensation and improve the wearing comfort when wearing contact lenses, 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. By the way, when performing surface graft polymerization, it is necessary to degas dissolved oxygen in the monomer solution. Conventionally, a typical method for this purpose has been to apply ultrasonic waves to a monomer solution in a vacuum to degas it.

[Problem to be solved by the invention]

However, the above-mentioned prior art does not mention the ultrasonic application conditions at all, which causes various problems. For example, if the ultrasonic application time is extremely short, dissolved oxygen in the monomer solution cannot be removed sufficiently, which may prevent the polymerization reaction from proceeding. On the other hand, if the application time is too long, the monomer solution will be concentrated and the monomer concentration will become high because vacuum is drawn during this time. In this case, the surface state obtained by surface grafting may differ from the original aim, or may lead to non-uniformity. Therefore, the present invention is intended to solve these conventional problems, and its purpose is to specify the ultrasonic application time and enable uniform processing with excellent reproducibility, which is especially required in mass production. An object of the present invention is to provide a method for manufacturing contact lenses.

[Means to solve the problem]

In order to solve the above problems, the method for manufacturing a conotact lens of the present invention includes (a) at least alkyl methacrylate, siloxanyl methacrylate A
OCH! Y and a methacrylate containing a fluorine substituent (where X and Y are a group consisting of a C1-c5 alkyl group and a Z group, 2 is a group having the structural formula %, and A is a 01-c5 alkyl group) Indicates the group.

k, l, , mSn represent ol or a positive integer. ) is a contact lens base material made from a polymer of methacrylic acid ester compound, which is a copolymer with (b).
) A method for producing a contact lens comprising a step of graft polymerizing acrylamide onto the lens surface, in which the dissolved oxygen in the aqueous solution containing the acrylamide monomer as a product in step (b) is removed by applying ultrasound under vacuum. When degassing, the application time is 10 seconds or more and 10
A method for manufacturing a contact lens, characterized in that the manufacturing time is less than 1 minute.

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

Pentamethyldisiloxanyl methyl methacrylate tris(trimethylsiloquine)-r-methacryloquine pill 7 run CIh CHrS 1-CHi ■ CHyS 1-CH! Hs Isobutylhexamethyltrilinoxanylmethyl methacrylate The details of the present invention will be illustrated below with reference to Examples.

[Example of implementation l]

10 g of acrylamide was weighed and dissolved in distilled water to make 100 ml to prepare an aqueous monomer solution.

Graft polymerization was carried out as follows. A contact lens base material made of a copolymer of 60 wt% methyl methacrylate, 35 wt% tris(trimethylnroxy)solylbrobyl methacrylate, and 5 wt% 2-hydroxyethyl methacrylate was prepared. Discharge device (electrode tube 6
Centimeters, voltage between electrodes 270 volts, frequency 60
The lens base material was placed in a 0.04 Torr argon atmosphere and subjected to glow discharge treatment for 5 seconds. After exposing the discharge-treated lens base material to the air, it was placed in a test tube, and the acrylamide monomer aqueous solution was added thereto, and then connected to a vacuum system. Subsequently, the test tube was immersed in water filled with an ultrasonic vibrating bath.

In this state, the inside of the tube was evacuated for 1 minute using a rotary pump, and then ultrasonic waves were applied. After a predetermined period of time had elapsed, the application of ultrasonic waves was stopped, the test tube was vacuum-sealed, and it was immersed in a constant temperature bath at 80° C. for 60 minutes to attempt graft polymerization onto the surface of the lens base material. The output and application time of the applied ultrasonic waves are as shown in Tables 1 and 2.

As is clear from Table 1, surface graft polymerization was possible when the ultrasonic wave application time was 10 seconds or more. It was found that when the application time was less than 10 seconds, the dissolved oxygen in the monomer solution could not be sufficiently removed and polymerization did not occur.

On the other hand, Table 2 reveals that when the ultrasonic application time is longer than 10 minutes, the monomer solution is concentrated, and as a result, white turbidity occurs over a part or the entire grafted surface. When the application time was 20 minutes or less, the condition of the grafted surface was good.

Table 1 No. 211 0 Good surface grafting condition × Poor surface grafting condition (cloudy) [Example 2] Methyl methacrylate 60 wt%, tris(trimethylnroquine)silylpropyl methacrylate 35 wt
%, 2-hydroxyethyl methacrylate) 5 wt
% of the copolymer was prepared. This lens base material was installed in a space created by a 1.5 mm thick spacer between the electrodes of a corona discharge treatment device with an inter-electrode distance of 3.5 cm, an inter-electrode voltage of 15 kilovolts, and a frequency of 60 Hz, and the discharge treatment was performed. I did it. 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 thereafter the same treatment as in Example 1 was performed. The results are shown in Tables 3 and 4.

As in Example 1, if the ultrasonic application time is less than 10 seconds, dissolved oxygen in the monomer solution cannot be sufficiently degassed.
Surface graft polymerization was not possible.

Furthermore, it was found that when the application time was longer than 10 minutes, clouding occurred on the surface after the surface grafting treatment. From the results in Tables 3 and 4, the application time is 10 seconds or more and 10
It has been found that a good surface grafting state can be obtained only when the temperature is less than 10 minutes.

Table 3: 0 Surface grafting possible Similar results were obtained for the surface treatment of polyethylene film, polypropylene, polyvinyl chloride, polyvinylidene chloride, acetate, polyester, polyvinyl alcohol, polystyrene, polycarbonate, and various other polymeric materials without being affected. Furthermore, the above-mentioned materials can be applied to various packaging materials, agricultural water retaining materials, and medical products such as artificial organs.

〔Effect of the invention〕

As described above, according to the present invention, since the range of ultrasonic application time when removing dissolved oxygen in a monomer aqueous solution is clarified, the application time is fixed at any point within this time range for degassing. By performing the treatment, reliable and uniform surface graft polymerization treatment is possible. Therefore, the present invention has great effects, especially in simplifying process control during mass production.

Claims (1)

[Claims] (a) At least alkyl methacrylates, siloxanyl methacrylates ▲ have mathematical formulas, chemical formulas, tables, etc. ▼ and methacrylates containing fluorine substituents ▲ have mathematical formulas, chemical formulas, tables, etc. ▼ (wherein X and Y is selected from the group consisting of C1 to C5 alkyl groups and Z groups, Z is a group having the structural formula ▲ Numerical formula, chemical formula, table, etc. ▼, and A represents a C1 to C5 alkyl group.k , l, m, and n are 0 or a positive integer.) In a contact lens base material made from a polymer of a methacrylic acid ester compound, which is a copolymer with In the method for manufacturing a contact lens, the method comprises the steps of: (b) performing a discharge treatment; and (b) grafting acrylamide onto the lens surface;
A contact characterized in that when degassing dissolved oxygen in an aqueous solution containing an acrylamide monomer as a main component during a process by applying ultrasonic waves under vacuum, the application time is 10 seconds or more and 10 minutes or less. How to manufacture lenses.