JPH10253931A - Hydrous contact lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen accumulation on the surface by the charge included in the protein, etc., in the lacrimal fluid, and to improve the economy and thermal stability, by constituting a hydrous contact lens of a polymer obtd. by polymerizing a monomer mixture consisting of a specific radial polymerizable polymer, etc., and making quaternary ammonium ions, etc., exist therein in a specific form. SOLUTION: This hydrous contact lens consists of a polymer obtd. by polymerizing the monomer mixture consisting of 0.5 to 49 pts.wt. radical polymerizable monomer having a quaternary ammonium salt, 0.5 to 49 pts.wt. radical polymerizable polymer which is the (meth)acryloyoxyethylcarbocylic acid expressed by the formula, 8 to 97 pts.wt. 2-hydroxyethyl methacrylate and 2 to 91 pts.wt. their copolymerizable monomer. The counter ions of the quaternary ammonium ions and the carboxyl ions are deoxidized or desalted and exist in the for of zwitter ions. In the formula, R denotes hydrogen atom or methyl group. X denotes a 2 to 6C alkyl group, phenyl group or cyclohexyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a quaternary ammonium ion and a carboxyl ion in which counter ions of a quaternary ammonium ion and a carboxyl ion are deoxidized or desalted to form a zwitter ion. The present invention relates to a water-containing contact lens excellent in thermal stability, which can greatly improve shape stability and mechanical strength by forming.

[0002]

BACKGROUND OF THE INVENTION Hydrous contact lens materials are generally
It is made from a hydrophilic derivative of acrylic acid or methacrylic acid (eg, a hydrophilic ester) or a copolymer based on a hydrophilic vinyl polymer such as acrylamide or vinylpyrrolidone. Of these, contact lenses containing vinylpyrrolidone as the main component are representative of high water content soft contact lenses, and because of their high water content, they have sufficient oxygen permeability, so they can be used for continuous wear and corneal protection for surgery. It is used as a medical use for

[0003] However, when the lens contains more than 70% by weight of water, there is a problem that the mechanical strength is greatly reduced, and it is further troublesome that various wastes contained in tears such as proteins, lipids and mucoids are contained. Are easy to accumulate on the surface. It is said that this tendency is not only due to the high water content, but also due to the interaction between the charge-bearing group present in the waste components and the charge associated with the surface of the water-containing contact lens. I have.

[0004] Efforts have been made to remedy these problems in various ways or by using specific monomers to reduce fouling. For example, Japanese Translation of International Patent Publication No. 6-5088
No. 58 describes that an anionic monomer and a cationic monomer are copolymerized with a contact lens component to form an aminide bond between a carboxyl group and an amine by a radical reaction, thereby further improving the stain resistance. I have.

[0005]

However, in the method disclosed in Japanese Patent Publication No. 6-508858, since the copolymer is a random blend, the copolymer is not necessarily contained in the copolymer by an ethylenically unsaturated inner salt or an aminide bond. It is difficult to say that an amphoteric ion pair is formed, and even if it is completely formed, it is thought that the effect of ionic charge in the base material has disappeared because it is an amide bond, and improvement in stain resistance is Not always enough. Further, it is considered that as the amount of the ionic monomer added increases, the mechanical strength decreases as in the past.

Accordingly, an object of the present invention is to form a complete zwitter ion by a quaternary ammonium ion and a carboxyl ion, and to greatly improve shape stability and mechanical strength by forming the zwitter ion. Provided is a highly economical, thermostable, water-containing contact lens that can significantly reduce surface accumulation due to charges contained in proteins, lipids, cell fragments, and other wastes in tears. It is in.

[0007]

According to the present invention, there is provided a radical polymerizable monomer having a quaternary ammonium salt of 0.5 to 49.
Parts by weight, 0.5 to 49 parts by weight of a radical polymerizable monomer which is (meth) acryloyloxyethyl carboxylic acid represented by the following general formula (1), 8-97 parts by weight of 2-hydroxyethyl methacrylate, It consists of a polymer obtained by polymerizing a monomer mixture consisting of 2 to 91 parts by weight of a monomer copolymerizable therewith, and quaternary ammonium ions and carboxyl ions are deoxidized or desalted. A hydrated contact lens having excellent thermal stability, characterized in that the quaternary ammonium ion and carboxyl ion obtained are present in the form of zwitter ions.

[0008]

Embedded image (In the formula, R represents a hydrogen atom or a methyl group. X represents an alkyl group having 2 to 6 carbon atoms, a phenyl group or a cyclohexyl group.) As X in the general formula (1), a hydrophobic alkyl group;
The reason that a phenyl or cyclohexyl group is used is based on the discovery that the presence of a hydrophobic moiety next to the carboxyl group significantly improves the thermal stability of the contact lenses of the present invention and is less susceptible to hydrolysis. Conversely, if the number of carbon atoms in X exceeds 6, hydrolysis resistance is improved, but hydrophobicity is increased and the water content is reduced. For this reason, in the present invention, X needs to be an alkyl group having 2 to 6 carbon atoms, a phenyl group, or a cyclohexyl group.

The present invention also provides the above-mentioned hydrous contact lens, wherein the water content is 35 to 85% by weight.

[0010] The present invention is also the above-mentioned water-containing contact lens, wherein the polymer is a water-mixed system and is obtained by polymerization in a mold having a shape corresponding to the desired product.

The present invention also provides the above-mentioned hydrous contact lens, wherein the polymerization is carried out by irradiation with ultraviolet rays.

Further, the present invention is the above-mentioned hydrous contact lens, wherein the deionization or desalting of the counter ions of the quaternary ammonium ion and the carboxyl ion is carried out with an aqueous alkali solution.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The contact lens of the present invention comprises a radically polymerizable monomer having a quaternary ammonium salt (hereinafter referred to as a quaternary ammonium salt-containing monomer) represented by the general formula (1). Radical polymerizable monomers (hereinafter, referred to as carboxylic acid-containing monomers) which are represented by (meth) acryloyloxyethyl carboxylic acid and 2-hydroxyethyl methacrylate (HEMA) are essential components. As an example, examples of the quaternary ammonium salt-containing monomer include dimethylaminoethyl methyl methoxide (meth) acrylate, dimethylaminoethyl methyl methacrylate chloride, dimethylaminoethyl methyl methacrylate sulfate, and methacrylamide dimethylamino. Propylmethyl chloride, vinylbenzyltrimethylammonium Chloride, and the like.
Of course, one type or two or more types may be used. Examples of the carboxylic acid-containing monomer include succinic acid 2-
Examples thereof include (meth) acryloyloxyethyl, 2- (meth) acryloyloxyethyl phthalate, and 2- (meth) acryloyloxyethyl hexahydrophthalate.

[0014] In the present invention, a quaternary ammonium ion (-N ⁺⁾ and carboxyl ion (-COO ^-), so that needs to be present in the form of a zwitterion, in the present invention, -N ⁺ / -COO ^The molar ratio is usually -N ⁺ / -C
OO ^- = approximately 0.8 to 1.2 is used as the preferred range. Further, the quaternary ammonium salt monomer, the carboxylic acid-containing monomer, it is necessary to adjust the monomer mixing ratio depending on the type of monomer, the quaternary ammonium salt-containing monomer 0.5 ~ 49 parts by weight, carboxylic acid-containing monomer 0.5-4
9 parts by weight are used. If the amount is less than 0.5 part by weight, a sufficient stain-resistant effect on proteins, lipids, mucoids and the like in tears will be poor, and if it exceeds 49 parts by weight, a contact lens having sufficient strength will not be obtained. In the present invention, the quaternary ammonium salt-containing monomer and the carboxylic acid-containing monomer are each preferably used in an amount of 1 to 30 parts by weight, since a better effect can be obtained.

Next, in the present invention, 2-
Although hydroxyethyl methacrylate is used, these are monomers having good hydrophilicity and can give sufficient strength to general contact lenses containing these monomers, and therefore are important in the present invention. Components
It is used in the present invention in the range of 8 to 97 parts by weight. Preferably, it is used in the range of 15 to 90 parts by weight.

In the present invention, monomers other than quaternary ammonium salt-containing monomers, carboxylic acid-containing monomers and 2-hydroxyethyl methacrylate are used. Is used for various purposes such as imparting strength to the polymer composition, controlling the water content, controlling the crosslink density, and further controlling the polymerization rate. Specifically, alkyl (meth) acrylate, fluoroalkyl (meth) acrylate, hydroxyalkyl (meth) acrylate, polyethylene glycol (meth) acrylate, polyhydric alcohol (meth) acrylate, vinyl (meth) acrylate and the like (Meth) acrylic acid esters, styrene derivatives, vinyl compounds such as N-vinyl lactam, and the like. More specifically, styrene, methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, tridecyl (meth) acrylate, 2-hydroxypropyl (Meth) acrylate, N, N-dimethylacrylamide,
N, N-dimethylaminoethyl (meth) acrylate,
In addition to monomers such as N, N-dimethylaminopropyl (meth) acrylamide, bisacrylamide, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di ( Bifunctional and polyfunctional monomers such as (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin di (meth) acrylate, glycerin tri (meth) acrylate, and allyl methacrylate are used. In the present invention, these monomers are used depending on the purpose of use.
Although it is used in the range of -91 parts by weight, if it exceeds 91 parts by weight, the hydrophilicity of the polymer becomes poor. Preferably 2-8
0 parts by weight, more preferably 2 to 50 parts by weight.

Next, the polymerizability of these compositions will be described. In the present invention, since a quaternary ammonium salt-containing monomer and a carboxylic acid-containing monomer are used as constituent components, polymerization can be performed in a water-mixed state. However, when the amount of these monomers is relatively small, it is possible to carry out the polymerization in a non-hydrated state. When the polymerization is carried out in a water-mixed state, the ratio of monomer / water is not particularly limited. In the present invention, water is usually used in an amount of about 0 to 300 parts by weight based on 100 parts by weight of the monomer. Next, the desired component composition is prepared, a normal radical polymerization initiator is added in a water-containing or non-water-containing state, and polymerization is carried out by heating or irradiation with ultraviolet light. For example, high energy using X-rays or electron beams is used. It is possible to carry out the polymerization using radiation.

The polymerization is carried out by injecting a water-containing or non-water-containing monomer composition into a contact lens-shaped mold or a test tube mold in advance and polymerizing to form a water-containing or non-water-containing product. Is obtained. The contact lens can be polished or used as it is.

In the present invention, the formed product obtained in the state of a counter ion is subjected to deoxidation or desalting treatment to form a zwitter ion. In this case, the formed product in the state of the counter ion is used. Although it is possible to transfer to zwitter ions even with an aqueous solution treatment at 50 ° C. or more, as shown in this example, it is necessary to perform deoxidation / desalting treatment using an alkaline aqueous solution to shift to zwitter ions. Is efficient and preferred.

[0020]

EXAMPLES The present invention will be described with reference to examples, but the present invention is not limited to these examples. [Example 1] 2-hydroxyethyl methacrylate 79
1 part by weight of dimethylaminoethyl methyl methacrylate chloride, 10 parts by weight of 2-methacryloyloxyethyl succinate, 1.2 parts by weight of water externally, and 0.6 parts by weight of ethylene glycol dimethacrylate and polymerization After mixing 0.06% of Darocur 1173 (manufactured by Ciba Geigy) as an initiator, the mixture was filled in a resin mold made of PP, and was then mixed with a high-pressure mercury lamp of 80 W / cm.
Ultraviolet rays were irradiated at an irradiation distance of 20 cm for 15 minutes to obtain a polymer. The obtained polymer was taken out from the resin mold, swelled and washed with ultrapure water, and then immersed in a 0.1% NaOH aqueous solution to perform a desalting treatment. Thereafter, the water content, swelling ratio, transparency, stain resistance, tensile strength, tensile elongation and dimensional stability of the copolymer obtained by washing again with ultrapure water are measured by the following methods. It was measured. Table 2 shows the measurement results.

In this example, the determination of chlorine was also performed. Immediately after the swelling and washing, the chlorine content in the lens after the alkali treatment was quantified by elemental analysis by the combustion flask method. As a result, it was 84% immediately after the swelling and 1.2% after the alkali treatment.

<Water content, swelling ratio> A sample obtained by drying the water-containing copolymer at room temperature under reduced pressure for a day and a night, and after drying, immersing in pure water and swelling, and then immersing in a 0.1% NaOH aqueous solution. The samples were immersed for desalting and then washed with pure water. The water content and the swelling ratio were determined by weight change and dimensional change.

Water content (% by weight) = (W1−W2) / W1 × 100 W1: Lens weight when saturated with water W2: Lens weight when dehydrated and dried Swelling ratio = S1 / S2 S1: Lens diameter when saturated with water S2 : Lens diameter when dehydrated and dried

<Stain Resistance> One lens was immersed in 5 ml of a known amount of an aqueous solution of lysozyme, allowed to stand at 40 ° C. for one week, and the amount of lysozyme adsorbed on the formed product was determined by a staining method.

<Tensile Strength, Tensile Elongation> A hydrous lens was cut into a 2.0 mm-wide strip to obtain a test sample. The test was performed in water (37 ° C.). The upper and lower ends of the test sample were sandwiched between jigs at 6.0 mm intervals, and were continuously pulled at a constant speed. The load (rupture strength) and elongation (elongation at break) at the time of breakage of the test sample were measured. The test was performed with the following tensile tester.

Measurement equipment: Shimadzu AGS-5A Distance between chucks: 6.0 mm Test speed: 100 mm / min Breaking strength (gf / mm ² ) = Load at break (gf) / Sample cross-sectional area (mm ² ) Breaking elongation (%) = Elongation (mm) / initial value (mm) × 10
0

<Dimensional stability> Thermal stability / chemical disinfection stability test: Stability of lens dimensions against heat treatment and chemical disinfection treatment was examined. 100 hours of boiling treatment for heat treatment and 50 treatments of concept F (Seed, etc.) for chemical disinfection
A cycle was performed. The lens dimensions (size, weight, base curve, power) before and after each treatment were measured.

[Examples 2 to 6 and Comparative Examples 1 to 4] A transparent copolymer was obtained in the same manner as in Example 1 except that the composition of the components used for the polymerization was changed as shown in Table 1. And

The physical properties of the obtained test piece were measured in the same manner as in Example 1. Table 2 shows the results.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

The counter ions of the quaternary ammonium ion and the carboxyl ion are present in the form of deoxidized or desalted zwitter ions. While showing high moisture content,
An optically homogeneous and economical contact lens having excellent shape stability, mechanical strength and stain resistance could be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuki Ikeda 2-40-2 Hongo, Bunkyo-ku, Tokyo Seed Co., Ltd.

Claims (5)

[Claims] A radical polymerizable monomer having a quaternary ammonium salt in an amount of 0.5 to 49 parts by weight, represented by the following general formula (1):
0.5 to 49 parts by weight of a radical polymerizable monomer which is a (meth) acryloyloxyethyl carboxylic acid represented by the formula: 8 to 97 parts by weight of 2-hydroxyethyl methacrylate, and a monomer copolymerizable therewith. Consisting of a polymer obtained by polymerizing a monomer mixture consisting of 2 to 91 parts by weight,
Water content excellent in heat stability characterized in that quaternary ammonium ions and carboxyl ions are present in the form of zwitter ions in which the counter ions of quaternary ammonium ions and carboxyl ions are deoxidized or desalted. contact lens. Embedded image (In the formula, R represents a hydrogen atom or a methyl group. X represents an alkyl group having 2 to 6 carbon atoms, a phenyl group, or a cyclohexyl group.) 2. The hydrous contact lens according to claim 1, wherein the water content is 35 to 85% by weight. 3. The water-containing contact lens according to claim 1, wherein the polymer is a water-mixed system and is obtained by polymerization in a mold having a shape corresponding to an object. 4. The hydrous contact lens according to claim 1, wherein the polymerization is carried out by ultraviolet irradiation. 5. The method according to claim 1, wherein the deionization or desalting of the counter ions of the quaternary ammonium ion and the carboxyl ion is performed with an aqueous alkali solution.
5. The hydrous contact lens according to 2, 3 or 4.