JPH03288816A - Production of contact lens - Google Patents

Abstract

PURPOSE:To assure graft polymn. and to uniformize the graft of a lens surface as well as to prevent the fluctuation with each solid by setting the polymn. time of a stage for graft polymn. of acrylamide on the lens surface at 5 to 90 minutes. CONSTITUTION:The polymer of the ester compd. of methacrylic acid which is the copolymer of at least the alkyl methacrylate and siloxanyl methacrylate of formula I (in the formula I, X and Y are selected from a group consisting of 1 to 5C alkyl group and Z group; Z is a group having formula II; A denotes 1 to 5C alkyl group; m, n denote 0 or positive integer) is used as a raw material. The polymn. time of the production process for the contact lens consisting of the stage for subjecting the surface of the base material of the contact lens to a discharge treatment under atm. pressure or reduced pressure and the stage for graft polymn. of the acrylamide on the lens surface is set at 5 to 90 minutes. The permanent enhancement of the effect of the subsequent surface reforming is possible in this way and the treatment in a large quantity and a drastic cost reduction are possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to contact lenses, and particularly to hard contact lenses that have excellent wettability and wear comfort.

[Prior Art] As a means of reducing the foreign body sensation when wearing contact lenses and improving the so-called wearing comfort, graft polymerization of a tree-philic monomer to the surface of the contact lens improves wettability, thereby bonding the cornea and the lens. There is a way to improve the conformability of the surface. In performing surface grafting, the surface is first subjected to electrical discharge treatment to generate radicals on the surface. At this time,
In order to make the grafts on the lens surface uniform and free from individual variations, it is necessary to optimize the polymerization time and control the amount of grafts produced.

Conventionally, it was thought that the longer the polymerization time, the larger the amount of grafting and the better the surface wettability.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, not only is the cost high if the polymerization time is too long, but also the graft monomers are three-dimensionally cross-linked to form a cross-linked polymer that is insoluble in water. . The surface wettability at this time is very poor. On the other hand, if the polymerization time is short, the growth of the graft polymer chains will be insufficient.
It had the disadvantage that its molecular weight was small and the amount of grafting was small. The present invention is intended to solve these problems, and its purpose is to provide a method that is sufficient to polymerize a large amount of graft polymer, while also preventing the resulting graft polymer from forming a three-dimensional crosslinked structure. An object of the present invention is to provide a contact lens manufacturing method that ensures graft polymerization by setting an optimum polymerization time.

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a contact lens of the present invention includes: (1) at least alkyl methacrylate and siloxanyl methacrylate (wherein X and Y are C1 to C5 alkyl and Z group, Z is a group having the structural formula %, and A represents an alkyl group of 01 to C5.

m and n are 0. Or indicates a positive integer. (2) 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 In the method for manufacturing a contact lens, the method comprises the step of (2)
It is characterized in that it is achieved by setting the polymerization time of the step to 5 minutes to 90 minutes.

Typical ester compounds of methacrylic acid include the following.

Tris(trimethylsiloxy)-γ-methacryloxypropylsilane CH3 CH3-Si-CH3 CH30 CH3-8i-CH3 H3 Pentamethyldisiloxanyl methyl methacrylate Isobutylhexamethyltrisiloxanyl methyl methacrylate CH3CH3CH3 [Action] Molding of contact lenses By subjecting the body to electrical discharge treatment, radicals are generated on the surface of the molded body. When this compact is exposed to an oxygen atmosphere, peroxides such as 10-0-H are produced.

Furthermore, when this is immersed in a wood-philic monomer solution and the temperature is raised, the peroxide decomposes and becomes an initiator, and polymerization begins.
Hydrophilic monomers will be grafted onto the lens surface.

Hereinafter, the details of the present invention will be shown by examples.

[Example 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 methacrylate was prepared. Discharge device (6 cm between electrodes, 270 volts between electrodes,
The lens base material is installed at a frequency of 60 Hz), and the frequency is 0.04
Glow discharge treatment was performed for 5 seconds in an argon atmosphere in a F-room. After exposing the discharge-treated lens base material to the air,
The tube was placed in a test tube, a 10 wt % acrylamide aqueous solution was added thereto, the atmosphere was replaced with nitrogen gas, and the tube was sealed under reduced pressure. The test tube was placed in a constant temperature bath at 60°C, and acrylamide was graft-polymerized on the surface of the lens base material. After polymerization, the lens was immersed in hot pure water at 70°C, and the by-product homopolymer was removed by stirring the late pure water. A total of 13 samples were prepared by performing the same operation while changing the polymerization time (Table 1). In addition, the contact angle of the lens surface with water was measured using a droplet method. In addition, the amount of acrylamide grafted was determined using the ninhydrin method. These results are listed in Table 1.

Table 1 *μgcm-2 [Example 2] Methyl methacryate 60wt%, tris(trimethylsiloxy)siwalpropylmethacrylate) 35wt%
A contact lens base material made of a copolymer of 5 wt % of 2-hydroxyethyl methacrylate was prepared. 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 an interelectrode distance of 3.5 cm, an interelectrode voltage of 15 kilovolts, and a frequency of 60 Hz, and subjected to discharge treatment. was carried out. 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, a 10 wt % acrylamide aqueous solution was added thereto, 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 60°C, and acrylamide was graft-polymerized on the surface of the lens base material.

After polymerization, the lens was immersed in hot pure water at 70'C, and the by-product homopolymer was removed by stirring the late pure water. A total of 13 samples were prepared by performing the same operation while changing the polymerization time (Table 2). In addition, the contact angle of the lens surface with water was measured using a droplet method. In addition, the amount of acrylamide grafted was determined using the ninhydrin method. These results are listed in Table 2.

Table 2 *μgcm-2 As is clear from Tables 1 and 2, samples 1 and 2, that is, polymerization times of 3 minutes or less, were due to insufficient radical chain transfer accompanying peroxide decomposition. Acrylamide did not graft and the contact angle did not decrease. 50
When the contact angle was longer than 60 minutes (sample 8°9.10), the contact angle decreased significantly, and especially when the contact angle was 60 to 70 minutes (sample 9.10), it reached the minimum value. However, when the polymerization time exceeded 90 minutes (sample 12.13), while the amount of grafting increased, the contact angle was high because a three-dimensionally crosslinked polymer was formed. This does not suit the purpose of surface modification.

As shown in Examples 1 and 2 above, it can be said that it is appropriate to set the polymerization time to 5 minutes to 90 minutes.

It is obvious that the optimum polymerization time will change if various pretreatment conditions such as the distance between the electrodes during discharge, the voltage, and the concentration of the monomer solution are changed. However, if there are some differences in conditions,
It is obvious that if the polymerization time is short, the polymerization will be insufficient, and if it is too long, a three-dimensional cross-linked polymer will be formed and the wettability will deteriorate, but by slightly changing the conditions, the polymerization time can be increased from 5 minutes to 5 minutes.
It is reasonable to set it to 90 minutes.

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 resins can be applied to various packaging materials, agricultural water retaining materials, and medical products such as artificial organs.

The effects it brings are significant, such as the ability to reduce costs.

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Claims (1)

[Claims] (1) 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. (2) 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 manufacturing a contact lens, characterized in that the polymerization time in step (2) is set to 5 minutes to 90 minutes.