JPS60200223A - Oxygen permeable hard contact lens - Google Patents

Abstract

PURPOSE:To improve oxygen permeability by using a specific copolymer. CONSTITUTION:A copolymer is obtd. by using >=40wt% total of the alkyl methacrylate (AMA) or alkyl acrylate (AA) expressed by the formula I (R1 is H or methyl, R2 is alkyl of 5-20C) and crosslinkable monomer and the ratio of using two kinds of these monomers is made 95/5-65/35 by weight. The copolymer is used in combination with the AMA or AA expressed by the formula II (R1 is the same as in the formula I , R3 is alkyl, etc. of 1-4C) in a <=60wt% range. A hydrophilic monomer is further incorporated into the copolymer in a <=20wt% range. For example, ethylene glycol dimethacrylate, etc. are used for the crosslinkable monomer and, for example, 2-hydroxy methacrylate, etc. are used for the hydrophilic monomer. The hard contact lens having desirable hardness and brittleness and excellent oxygen permeability is obtd. by using such compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oxygen permeable rigid contact lens made of a novel copolymer.

Recently, regular oxygen permeable rigid contact lenses have gained wide market acceptance. These oxygen-permeable hard contact lenses have excellent machinability and durability because the material itself is hard, and their good oxygen permeability allows oxygen to be supplied to the cornea from the outside air through the contact lens. Therefore, it is safe and has no risk of causing metabolic disorders of the cornea. Also,
Since it is substantially water-free, there is no risk of contamination with bacteria, etc., and it has excellent dimensional stability.

Conventional materials for this type of contact lenses include copolymers of siloxanylalkyl methacrylate and methyl methacrylate, copolymers of fluoroalkyl methacrylate and methyl methacrylate, and polymers using styrene monomers as the main component. Such,
Various materials have been reported, but among them, it is said that a material containing siloxanyl alkyl methacrylate as a main component is preferred because it provides a material with particularly excellent oxygen permeability.

However, in general, the above-mentioned silicone-containing monomers are not commercially available, and even if they are available, they are expensive, which poses problems particularly in terms of production efficiency and cost, and improvements have been desired.

Therefore, the present inventors continued research to improve the production efficiency and reduce material costs of hard contact lenses with excellent oxygen permeability. We have discovered that the copolymer as a component can be preferably used as an oxygen permeable hard contact lens material,
The present invention has now been completed.

That is, the present invention relates to the general formula (I) Bird CH,=C-C-0--(I) 1 (wherein, R1 is a hydrogen atom or a methyl group, and Bird is a linear or A copolymer obtained by using an alkyl methacrylate or alkyl acrylate represented by (representing a branched alkyl group) and a crosslinking monomer in a total amount of 40% by weight or more, wherein the usage ratio of these two monomers is The object of the present invention is to provide an oxygen permeable hard contact lens made of a copolymer having a ratio of 95:5 to 65:35.

Examples of the alkyl methacrylate or alkyl acrylate corresponding to the general formula (I) include pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, and tetradecyl. Methacrylate, pentadecyl methacrylate, hexadecyl methacrylate, hetadecyl methacrylate, octadecyl methacrylate,
Nonadecyl methacrylate, 2-ethylthimethyl methacrylate, 2-nibblehexyl methacrylate), 2-ethyl-4-methylpentyl methacrylate, 3.5.5-)limethylhexyl methacrylate, bis(2-methylpropyl)methyl methacrylate, 3.
Examples include alkyl methacrylates such as 7-dimethyloctyl methacrylate and acrylate compounds corresponding to these methacrylate compounds;
The crosslinking monomer used by selecting one species or two or more species may be any compound having two or more polymerizable groups in the molecule, such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol dimethacrylate, Dimethacrylate compounds such as methacrylate, triethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate, or diacrylate compounds corresponding to these dimethacrylate compounds, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, allyl methacrylate, allyl acrylate, vinyl Examples include methacrylate, vinyl acrylate, diallyl phthalate, and divinylbenzene, and one or more of these may be selected and used.

The weight ratio of the alkyl methacrylate or alkyl acrylate represented by the general formula (I) to the crosslinking monomer is 95:5 to 65:35, preferably 90:10 to 70:30. It is. That is, the alkyl methacrylate or alkyl acrylate polymer represented by the general formula (I) has extremely high rubber elasticity, and in order to have good machinability, the crosslinking monomer must be added at a weight ratio of 5/5. On the other hand, increasing the proportion of crosslinking monomer used increases machinability and hardness, but on the other hand, the material tends to become brittle, and oxygen permeability also decreases accordingly. Therefore, it is necessary that the weight ratio of the crosslinking monomer is 35/65 or less.

In a preferred embodiment of the invention, the general formula (I
I) ・° Bird (in the formula, Toshi is the same as above, Bird is a linear or branched alkyl group having 1 to 4 carbon atoms, and the alkyl group may be substituted with halogen) Use together with alkyl methacrylate or alkyl acrylate.

Examples of such compounds include methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, inbutyl methacrylate, t-butyl methacrylate, trifluoroethyl methacrylate, bis(trifluoromethyl)methyl methacrylate, and tris(trifluoromethyl)methyl methacrylate. compounds and acrylate compounds corresponding to these methacrylate compounds, among which one
Select and use one species or two or more species. Among them, in the general formula (II), the avian alkyl group has 3 to 4 carbon atoms.
It is preferable to use a branched chain.

These compounds have high hardness as polymers themselves, but are not so good in terms of oxygen permeability, so the amount used should be 60% by weight or less of the total monomers used for copolymerization. It is.

That is, if 60% by weight or more is used, the resulting copolymer will be inferior in the desired oxygen permeability.

Furthermore, in the present invention, for the purpose of imparting hydrophilicity to the surface, an ordinary hydrophilic hexamer can also be used.

Examples of such hydrophilic seven polymers include 2-hydroxyethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxybutyl methacrylate, 2.
3-dihydroxypropyl methacrylate, polyethylene glycol monomethacrylate, N-vinyl-2-pyrrolid/, N.

Examples include N-dimethylacrylamide, acrylamide, and one or more selected from these. The amount used should be 20% by weight or less of the edible food to be subjected to copolymerization from the viewpoint of maintaining the water-free properties of the resulting copolymer.

The copolymer of the present invention can be easily produced by a method commonly used in the technical field. For example, using a radical polymerization initiator commonly used in the polymerization of unsaturated hydrocarbon compounds,
It can be carried out at a temperature of °C. Examples of radical polymerization initiators that can be used include benzoyl peroxide, azobisisobutyronitrile, azobisdimethylvaleronitrile, and acetyl peroxide.
One or more of these may be selected and used. The amount used is suitably in the range of about 0.01 to 1% by weight based on the total monomer mixture to be subjected to polymerization. Molding into contact lenses can also be carried out by a conventional method. For example, after polymerization is carried out in a suitable mold or container to obtain a block-shaped, plate-shaped or round bar-shaped material, the desired contact lens can be formed by ordinary machining such as cutting and polishing, or machining operations can be carried out. To make it easier, polymerization is carried out in a mold that corresponds to the shape of the contact lens, and the product is directly molded into a shape close to the shape of the contact lens.
This can also be mechanically finished to form a desired contact lens.

The oxygen-permeable hard contact lens of the present invention as seen above has (a) hardness and rigidity desirable for a hard contact lens, and is brittle as well, mainly consisting of siloxanyl alkyl methacrylate, which has been conventionally used. This is a hard contact lens with improved durability compared to conventional oxygen permeable hard contact lenses. Lens (oxygen permeability coefficient is approximately 1.OX 10-1' atOz-cs
It has the advantage that it can be produced at a considerably lower cost compared to lenses (N/CD-SEE/WR H6 or higher).

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these embodiments.

Example 1 52.5 parts of 2-ethylbutyl methacrylate) +7
40 parts of fluoroethyl methacrylate, 7.5 parts of ff-ethylene glycol dimethacrylate, and 0.1 part of 2,2'-azobis-(2,4-dimethylvaleronitrile) as a polymerization initiator were thoroughly mixed and placed in a glass test tube. It was injected into the container and sealed with a stopper. Put this in a circulating constant temperature water tank,
39 hours at 35°C, 4 hours at 50°C, 1.5 hours at 60°C, 1.5 hours at 70°C, 1.5 hours at 80°C, 90°C
1 hour at 100℃, 1 hour at 110℃, 12
Heat polymerization was carried out stepwise at 0°C for 1 hour and at 130°C for 1.5 hours. The resulting colorless and transparent polymer was cut and machined by cutting and polishing to obtain a hard contact lens. When the physical properties of the hard contact lens observed were measured, it was found that the oxygen permeability coefficient was 1.43 x 10-" (ml
It had a Vickers hardness (7.5 NHV) of 8.8 and a refractive index of 1.46.

Note that each physical property value was measured according to the following method.

(1) Oxygen permeability coefficient (do, ・crn / cd ・
wm Hg) was measured using a Seikaken film oxygen permeability meter manufactured by Rika Seiki Kogyo Co., Ltd., on a test piece with a diameter of 13 mm and a thickness of 0.2 m in 0.9% physiological saline at 35°C. It was measured.

(2) Vickers hardness (7.5 NHV) was measured using a hardness meter manufactured by Akashi Seisakusho Co., Ltd. in a constant temperature and humidity room at 20° C. and 50% RH on a test piece with a diameter of 13 blinds and a thickness of 4 rugs.

(3) The refractive index (nto) was measured on a test piece with a diameter of 13 snc and a thickness of 4M in a constant temperature and humidity room at 20° C. and 50% RH using a new Elma Atsube refractometer manufactured by Elma Optical Co., Ltd.

Examples 2 to 17 Each monomer component and its usage amount in copolymerization were
Experiments were conducted in the same manner as in Example 1, except that the lenses were changed to those shown in the table, and the desired oxygen-permeable hard contact lenses were obtained. Their main physical property values are also shown in Table 1.

Claims (1)

[Claims] (1) General formula (I) CH2=C-C-0-bird (I) 1 (wherein, R is a hydrogen atom or a methyl group, and bird has 5 to 20 carbon atoms. A copolymer obtained by using an alkyl methacrylate or alkyl acrylate represented by (representing a straight-chain or branched alkyl group) and a crosslinkable monomer in a total amount of 40% by weight or more, the copolymer being obtained by using a total of 40% by weight or more of a crosslinking monomer, An oxygen-permeable hard contact lens made of a copolymer, characterized in that the ratio of use of the copolymer is 95=5 to 65:35 by weight. e) The copolymer has the general formula (II) CH2=C-C-0-Tori (II) 1 (In the formula, Toshi is the same as above, and Tori is a linear or branched chain having 1 to 4 carbon atoms. The oxygen-permeable hard material according to claim 1, which contains an alkyl methacrylate or alkyl acrylate represented by an alkyl group (which may be halogen-substituted) in an amount of 60% by weight or less. contact lens. (3) The oxygen permeable hard contact lens according to claim (1), wherein the copolymer contains a hydrophilic monomer in an amount of 20% by weight or less;