JPH04316012A - Contact lens manufacturing method - Google Patents

Abstract

PURPOSE:To enhance the wear resistance of graft chains and transparency and to hold high wettability for a long period by restricting an amount of N,N'-methylenebisacrylamide to be added. CONSTITUTION:The polymer to be used as the starting material to fabricate the contact lens is the polymer of (meth)arcylate, such as siloxyalkyl (meth) acrylate represeted by formula I in which R is H or methyl, and each of X and Y is 1-6C alkyl, cycloalkyl, phenyl, or the like. The concentration of the N,N'-methylenebisacrylamide in an aqueous monomer solution composed of acrylamide, N,N'-methylenebisacryamide, and water to be used in the manufacturing process is regulated to <=10wt.%.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to contact lenses, and more particularly to hard contact lenses that have excellent wettability and wear comfort.

0002

2. Description of the Related 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. Furthermore, in order to maintain wettability over a long period of time, there is a method of crosslinking graft chains to improve wear resistance. Conventionally, it has been thought that the greater the amount of crosslinking agent added, the more the crosslinking effect improves and the wear resistance of the graft chains can be improved.

0003

However, the above-mentioned prior art has the drawback that light scattering occurs in the graft polymer layer on the lens, resulting in cloudy lens surfaces and poor transparency. The present invention is intended to solve this problem, and its purpose is to provide a method for manufacturing a contact lens that maintains high wettability over a long period of time and has excellent transparency.

0004

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a contact lens of the present invention provides a siloxy-substituted ester of acrylic acid or methacrylic acid (

[0005]

[Chemical formula 11]

), fluoroalkyl-substituted acrylic acid or methacrylic acid having not more than 20 fluorine atoms represented by the following general formula (

[0007]

[Chemical formula 12]

), polyfluoroalkylsiloxy-substituted esters of acrylic acid or methacrylic acid represented by the following general formula (

[0009]

[Chemical formula 13]

), acrylic (methacrylic)oxyalkylsilanol (

[0011]

[Chemical formula 14]

), polyacrylic represented by the following general formula (
methacrylic)oxyalkylpolysiloxane (

001
3]

[Chemical formula 15]

), fluorine-containing siloxanyl methacrylate (

[0015]

[Chemical formula 16]

), a fluorine-containing acrylic acid or methacrylic acid ester monomer (

00
17]

[Chemical formula 17]

), a fluorine-containing acrylic acid or methacrylic acid ester monomer represented by the following general formula

001
9]

[Chemical formula 18]

), a fluorine-containing diacrylate or dimethacrylate monomer (

002
1]

[Chemical formula 19]

) and fluorine-containing cyclic olefins (

[0023]

[C20]

Regarding a contact lens base material made from a polymer of an ester compound of acrylic acid or methacrylic acid, which is a copolymer containing at least one of the above, (a) its surface is subjected to normal pressure or reduced pressure; (b) a step of graft polymerizing acrylamide onto the lens surface; It is characterized in that the concentration of N,N'-methylenebisacrylamide in the monomer aqueous solution is 10 wt% or less.

[0025] Typical compounds represented by the above general formula include the following.

Fluorobutylhexamethyltrisiloxanyl methacrylate

[0027]

[C21]

Trifluoroethyl methacrylate

00
29]

[C22]

Trifluoropropyltetramethyldisiloxanyl methyl methacrylate

[0031]

[C23]

[0032] The details of the present invention will be explained below with reference to Examples.

[0033]

【Example】

(Example 1) γ-methacryloxypropyl-tris (
trimethylsiloxy)silane 48wt%, 2,2,2-
Trifluoroethyl methacrylate 19wt%, 1,3
-bis(γ-methacryloxypropyl)-1,1,3
, 3-tetrakis(trimethylsiloxy)disiloxane 8wt%, bis(trimethylsiloxy)-γ-methacryloxypropylsilanol 7wt%, methacrylic acid 1
A contact made of a copolymer of 0 wt%, methyl methacrylate 1 wt%, ethylene glycol dimethacrylate 7 wt%, and 2,2'-azobis(2,4-isobutyronitrile) (as a polymerization initiator) 0.25 wt%. A lens base material was prepared. The lens base material was placed in a discharge device (electrode spacing 6 cm, interelectrode voltage 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 form an aqueous monomer solution. At that time, six types of aqueous solutions were prepared in which the weight ratio of each component was changed according to Table 1. 2.5 ml of each aqueous solution was dispensed into test tubes 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. 8 test tubes
The monomers were graft-polymerized onto the surface of the lens base material by placing them in a constant temperature bath at 0° C. for 60 minutes (Samples Nos. 1 to 6).

In addition, for comparison with the conventional method, samples were 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 Sample No. It was exactly the same as in times 1 to 6.

[0036] The transmittance of the lens after the graft treatment in visible light (480 nm) was measured to evaluate the degree of cloudiness of the lens. The results are listed in Table 1.

[0037]

[Table 1]

Continuing on, regarding lenses with high transmittance and no clouding (Table 1, same as samples Nos. 1 to 4),
Tests were conducted to confirm the wear resistance of each.

First, the surface was rubbed 1000 times with the palm of the hand coated with detergent. Next, the contact angle of the lens surface after rubbing was measured, and the degree of peeling of the graft polymer was evaluated by looking at the difference between the contact angle and the pre-recorded contact angle before rubbing.

For comparison, 10Wt without adding crosslinking agent
% acrylamide aqueous solution system (Table 1,
Same as Comparative Examples 1 to 6) Sample No. The same operations as in steps 1 to 4 were performed.

[0041] The contact angle was measured by the droplet method, and water was used as the solvent. These results are listed in Table 2.

[0042]

[Table 2]

(Example 2) 48 wt% γ-methacryloxypropyl-tris(trimethylsiloxy)silane,
1,1-dihydroperfluorobutyl methacrylate 1
9 wt%, 1,3-bis(γ-methacryloxypropyl)-1,1,3,3-tetrakis(trimethylsiloxy)disiloxane 7 wt%, bis(trimethylsiloxy)-γ-methacryloxypropylsilanol 8 wt%
, 11 wt% methacrylic acid, 7 wt% ethylene glycol dimethacrylate, 2,2'-azobis(2,4-
isobutylnitrile) (as a polymerization initiator) 0
．． A contact lens base material made of a 25 wt % copolymer 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 inter-electrode distance of 3.5 cm, an inter-electrode voltage of 15 kilovolts, and a frequency of 60 hertz. Discharge treatment was performed. Incidentally, discharge treatment was applied to one side and both sides for 40 seconds each.

Next, as in Example 1, prepare 2.5 ml of monomer aqueous solutions with different component ratios in test tubes, add Mohr's salt (ferrous ammonium sulfate) as a redox catalyst to each, and stir. , dissolved. A discharge-treated lens base material was placed therein, and after nitrogen gas substitution, the tube was sealed under reduced pressure. The test tube was placed in a constant temperature bath at 30 to 50°C for 40 to 90 minutes, and the monomer was graft-polymerized on the surface of the lens base material (
Sample No. 1-6).

[0046] For comparison, 10w with no crosslinking agent added
A sample was prepared using a t% acrylamide monomer aqueous solution. (Comparative Examples 1 to 6) The polymerization conditions at this time were Sample No.
．． It was exactly the same as in times 1 to 6.

[0047] The transmittance of the lens after the graft treatment in visible light (480 nm) was measured to evaluate the degree of cloudiness of the lens. The results are listed in Table 3.

[0048]

[Table 3]

Continuing on, regarding lenses with high transmittance and no clouding (Table 3, same as samples Nos. 1 to 4),
Tests were conducted to confirm the wear resistance of each.

First, the surface was rubbed 1000 times with the palm of the hand coated with detergent. Next, the contact angle of the lens surface after rubbing was measured, and the degree of peeling of the graft polymer was evaluated by looking at the difference between the contact angle and the pre-recorded contact angle before rubbing.

For comparison, 10wt without adding crosslinking agent
% acrylamide aqueous solution system (Table 3,
Same as Comparative Examples 1 to 6) Sample No. The same operations as in steps 1 to 4 were performed.

[0052] The contact angle was measured by the droplet method, and water was used as the solvent. These results are listed in Table 4.

[0053]

[Table 4]

As is clear from Tables 1 and 3, in the polymerization solution consisting of at least acrylamide, N,N'-methylenebisacrylamide and water, N,N'
- Those containing 10 wt % or less of methylene bisacrylamide (Samples 1 to 4) were excellent in transmitting visible light, and no clouding of the lens surface was observed. Moreover, the transmittance value at this time was not inferior to that of the polymers in the 10 wt % acrylamide aqueous solution system (Comparative Examples 1 to 6), and was a sufficiently satisfactory value for the transparency of the contact lens. On the other hand, N,
For those containing more than 10 wt % of N'-methylenebisacrylamide (Samples Nos. 5 and 6), the lens surface became cloudy and the transmittance was significantly reduced.

[0055] Furthermore, as is clear from Tables 2 and 4,
The increase in contact angle after rubbing was significantly suppressed for those to which a crosslinking agent was added (Samples Nos. 1 to 4), and the water wettability of the lens surface was maintained. These results confirmed that the graft contact lens without clouding had sufficient durability and commercial value.

As described above, a graft contact lens which is highly durable and has no clouding on the lens surface was able to be produced.

Although the embodiments of the present invention have been explained using fluoroalkyl-containing contact lenses, similar results can be obtained with hard contact lenses of other compositions and soft contact lenses such as silicone rubber. ing.

Furthermore, similar results were obtained for surface treatments of polyethylene film, polypropylene, polyvinyl chloride, polyvinylidene chloride, acetate, polyester, polyvinyl alcohol, polystyrene, polycarbonate, and various other polymeric materials.

In addition, the above-mentioned resins can be applied to various packaging materials, agricultural water retaining materials, and medical products such as artificial organs.

In the examples of the present invention, acrylamide was used as a hydrophilic monomer, and N,N'-
The explanation was given using methylene bisacrylamide as an example, but
Other hydrophilic monomers including, but not limited to, 2-hydroxyethyl methacrylate, polyvinyl alcohol,
It can also be applied to N-vinylpyrrolidone, polyethylene oxide, dimethylacrylamide, etc. Furthermore, it can also be used as a crosslinking agent for 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. can.

[0061]

[Effect of the invention] As described above, according to the invention, N,
By limiting the amount of N'-methylenebisacrylamide added as stated in the claims, it was possible to improve the wear resistance of the graft chains and maintain high wettability over a long period of time. Moreover, no surface cloudiness was generated and the original optical properties of the lens were not deteriorated. Therefore, it can be said that the present invention is very effective in producing contact lenses that are comfortable to wear.

Claims (1)

[Claims] Claim 1: A siloxy-substituted ester of acrylic or methacrylic acid having the general formula: Fluoroalkyl-substituted acids ([Chemical formula 2]), polyfluoroalkylsiloxy-substituted esters of acrylic acid or methacrylic acid represented by the following general formula ([Chemical formula 3]), acrylic acids represented by the following general formula ([Chemical formula 3]) methacrylic) oxyalkylsilanol ( [Chemical formula 4] ), polyacrylic (methacrylic) represented by the following general formula
Oxyalkyl polysiloxane (Chemical formula 5), fluorine-containing siloxanyl methacrylate (Chemical formula 6) represented by the following general formula, fluorine-containing acrylic acid or methacrylic acid ester monomer represented by the following general formula ( [Chemical 7] ), a fluorine-containing acrylic acid or methacrylate monomer represented by the following general formula [Chemical 8] ), a fluorine-containing diacrylate or dimethacrylate monomer ( [ The raw material is a polymer of an ester compound of acrylic acid or methacrylic acid, which is a copolymer containing at least one of the following: In a contact lens manufacturing method comprising: (a) discharging the surface of the contact lens base material under normal pressure or reduced pressure; and (b) graft polymerizing acrylamide onto the lens surface. At least acrylamide, N,
1. A method for producing a contact lens, which comprises controlling the concentration of N,N'-methylenebisacrylamide in an aqueous monomer solution comprising N'-methylenebisacrylamide and water to 10 wt% or less.