HUT70585A - Method for preparing dye useful for tinting contact lenses - Google Patents

Abstract

The invention relates to a high purity jrto nomer ink unit suitable for coloring contact lenses. The above monomer dye units are prepared by reacting a hydrophilic monomer in an aqueous solution with a dye in the presence of a base, with a molar amount of base greater than or equal to the molar amount of dye. 80961-6384 Ski

Description

The present invention relates to a unit of high purity "roto nomer" dye suitable for coloring contact lenses. The above monomer dye units are prepared by reacting a hydrophilic monomer in an aqueous solution with a dye in the presence of a base, wherein the molar amount of the base is greater than or equal to the molar amount of the dye.

80961-6384 Si

PUBLICATION LITERATURE

Representative:

Danubia Patent and Trademark Office Ltd.

APPLICABLE FOR COLORING CONTACT LENSES

FOR THE PRODUCTION OF DYES

Johnson and Johnson Vision Products, Inc., Jacksonville,

FI, US

inventors:

MOLOCK Frank F., Orange Park, FI, US

FORD James D., Orange Park, FI, US

HILL Gregory A., Ponté Vedra Beach, FI, US

WOOD Joe M., Jacksonville, FI, US

Date of filing: 23.1.1995

Priority: January 24, 1994 (08/185,747) US

80961-6384 Si

The present invention relates to a process for coloring contact lenses. More particularly, the present invention relates to an improved process for the preparation of a highly pure compound of a hydrophilic monomer and a dye.

A conventional method of applying uniformly dispersed dye to soft contact lenses is described, for example, in U.S. Patent No. 4,468,229. Usually, the lens is first soaked in an aqueous solution of the paint, and then the paint is bound to the lens in another solution. The lens typically consists of a hydrophilic polymer resulting from the polymerization of hydrophilic monomers. Binding of the ink to the lens is accomplished by contacting the soaked lens with an aqueous base prior to the final hydration step, which is intended to provide the soft hydrogel lens with the desired amount of water at an acceptable pH.

The dyes used in the known process are typically derived from a halo-triazine such as a dihalo-triazine or a monohalo-triazine, especially water-soluble dichlorotriazines. For example, dichlorotriazine or monohalo-triazine dyes containing sulfonate functional groups are soluble in water, and therefore, binding to the lens hydrophilic polymer must occur before the final hydration step. Otherwise, the toner may move around the lens, creating an uneven distribution or filtering out of the lens into the wearer's eyes.

The ink, which provides the color of soft lenses produced by the conventional method, not only disperses the lens in the lens, but also does not migrate within the lens or filter. • · · ·

- 3 out of the lens after the bond has formed. The colored lens is stable even in aqueous media, repeatedly exposed to high temperatures, which occur during routine wear and cleaning. In the conventional method, the lenses are soaked in a solution containing the dye at a specific concentration and having a specific conductivity such that the dye diffuses into the polymer. The conductivity is significant because the swelling of the lenses can be controlled by selecting different salt concentrations. It is also important that the concentration of the dye and the time during which the lens is in the dye-soak liquid are accurately controlled, since diffusion kinetics determine the intensity of tinted contact lenses. In the conventional process, the paint is used in high concentrations in the paint soak to ensure continuous coloring. Unfortunately, this process is cumbersome and requires several steps, especially in industrial scale production, since the lenses must be soaked in a solution containing a specific concentration of paint for a certain period of time to disperse the paint in the lens. This problem therefore necessitated the development of other procedures.

U.S. Patent 4,559,059 discloses that a monomer such as 2-hydroxyethyl methacrylate may be reacted with a reactive dye prior to polymerization, and thereafter the monomer dye unit may be polymerized during the polymerization of the lenses forming the lens. However, this patent does not disclose either the process or the reaction conditions required to prepare the polymerizable monomer dye units. The impurities of the agent ···· ··· «

- varying from high concentrations of 4 single salts to surfactants used as dusting agents. Impurities are inorganic salts used to accelerate the dissolution of auxiliaries used in the process, such as paints. These components are added because the main application of these inks is the dyeing of cellulosic fabrics. These additives make the reactive dye even more reactive in textile dyeing processes. Synthetic impurities include dye precursors and reaction by-products. These substances are inactive and must be removed from industrial waters before being discharged into the sewer system. By reacting the above dyes with hydrophilic monomers, monofunctional monomer dye units are usually obtained in low yields. Therefore, one object of the present invention was to provide a high purity monomer dye unit. It is a further object of the present invention to provide a process for the preparation of a high purity monomer dye unit.

The disadvantages of typical reactions for coupling a dye to a hydrophilic monomer unit result from the contamination of commercially available dyes commonly used for dyeing contact lenses.

In U.S. Patent No. 4,157,892, a functional group is incorporated into the polymer from which the lens is made which is capable of reacting with the dye. The functionalized polymer is prepared by reacting a coupling monomer with a conventional hydrophilic monomer. This coupling monomer is likely to change the physical properties of the polymer. The lenses made from the functionalized polymer are immersed in a solution of a diazonium dye, where the dye is then bonded to the polymer. Although proper binding is achieved, this process also requires immersion of the finished lens in a dye solution.

Another method for coloring soft lenses is described in U.S. Patent No. 4,640,805. In this patent, colored lenses are produced by conventional rotary molding techniques. A suspension of the dye pigment in the liquid monomer is applied to the surface of the mold prior to polymerization of the rotating monomer. Although this method can easily color the surface of the lenses, the shape has to be stamped or stamped with specific geometry and size.

Attempts have been made to introduce dye into the lenses by polymerizing the hydrophilic monomer from which the lens is made in the presence of the dye. For example, U.S. Patent No. 4,252,421 describes the polymerization of a hydrophilic monomer in the presence of a water-insoluble phthalocyanine dye. It was assumed that the ink would remain trapped in the finished hydrated lens because it was not compatible with water. However, the lenses obtained by polymerization of the most commonly used hydrophilic monomer, hydroxyethyl methacrylate (HEMA), filter out the dye when the lens is fully hydrated at about 40% by weight. This is even more problematic for materials with higher water content.

U.S. Patent No. 4,252,421, above, discloses the functionalization of a dye with a polymerizable vinyl group followed by a linkage of the functionalized dye ····

6 during the polymerization of the monomers forming the lenses. Although this eliminates the need for a post-curing step, the water content of the lenses has a detrimental effect unless the hydrophilic -SO3H or -SO3Na groups are added to the phthalocyanine dye core (as discussed in column 8 of the patent). This, in turn, represents another arduous step in the process of making a contact lens suitable for long-term wear.

Similarly, EP 0 396 376 discloses the use of an uncharged anthraquinone dye, which is functionalized with a polymerizable group which promotes the binding of the functionalized dye during the polymerization of the hydrophilic monomer. Unfortunately, the lack of charge leads to lower water solubility (if any) in the paint, which in turn limits the amount of paint that can be used in the lens. More importantly, however, a functionalized anthraquinone dye is necessarily a bifunctional dye in this case. As a result of these two functions, the paint acts as a cross-linking agent. As a result, the water content of the lenses is further reduced, and lenses produced with such a dual-function dye are unacceptably hard when the concentration of the dye in the lens increases.

Finally, a further attempt to color contact lenses is described in U.S. Patent No. 4,639,105. According to this description, a mixture of liquid monomer, soluble dye, and pigment particles is processed by rotary molding to produce lenses of various colors, wherein the color of the lens is formed by the migration of the pigment particles.

- 7 • · «• · · •« · · · ················································································································· her. Although this specification indicates that the dye does not migrate, it does not mention what specific dye has been used, and it is believed that such dyes will in fact migrate or filter out during wear unless the dye used is functionalized with a polymerizable group as described above. We mentioned. In addition, such lenses are not suitable for applications where uniform distribution of the dye or colorant is necessary or desirable.

Given the above shortcomings of the prior art, there is a real need for an economical process for producing colored contact lenses which does not involve immersion of the finished lens in a dye solution.

The present invention relates to an improved process for the preparation of polymerizable monomer dye compounds which can then be polymerized with monomers which form the material of soft hydrogel contact lenses. The improvement consists in reacting the dye with the hydrophilic monomer under conditions to obtain a high purity, polymerizable, monofunctional dye. The high purity monofunctional dye is then polymerized in the presence of a homogeneous solution of the monomers used to make the soft hydrogel contact lenses. The improved process of the present invention eliminates the need to immerse lenses in an aqueous dye solution after polymerizing the hydrophilic monomer used to make the finished lens. In addition, it is not necessary to attach the paint to the lens after forming the lens. This is possible because the polymerizable monofunctional dye polymerizes with the hydrophilic monomers used to make the soft hydrogel contact lens and thus forms an integral part of the polymer backbone of the lens.

The color intensity of the lens can be precisely controlled by the concentration of the polymerizable monofunctional dye in the solution of the hydrophilic monomer. In addition, the physical and optical properties of the tinted lens are substantially the same as those of the corresponding lens without dye incorporation. Thus, for example, handling characteristics, wearing comfort, and lens cleaning are not impaired when the dye is incorporated into the lens by the improved process of the present invention. More importantly, this polymerizable monofunctional dye does not act as a crosslinking agent, since it is essentially monofunctional and thus incorporates larger amounts of dye without sacrificing the water content or handling characteristics of the lens, such as its flexibility.

A preferred class of halo-triazine dyes used to react with the hydrophilic monomeric 2-hydroxymethyl acrylate are dihalo-triazine dyes, in particular dichlorotriazine dyes, which contain at least one sulfonate functional group which renders the dye water-soluble. Such dichlorotriazine dyes are described, for example, in U.S. Patent Nos. 4,559,059 and 4,891,046, the entire contents of which are incorporated herein by reference. The most preferred dichlorotriazine dye is the Color Index Reactive Blue 4. Monochlorochlorothiazine dyes containing at least one sulfonate function, such as Reactive Blue 2, may also be reacted with 2-hydroxymethacrylate in the lens material. Examples of water-soluble inks other than Color Index Reactive Blue 4 include Procion Blue MRS, Fiber

Reactive Brilliant Blue MRS, 1-Amino-4- {3 - [(4,6-dichloro-triazin-2-yl) -amino] -4-sulfoanilino} -9,10-dihydro-9,10- dioxo-2-anthracenesulfonic acid disodium salt, 1-amino-4- {3 - [(4,6-dichloro-1,3,5-triazin-2-yl) amino] -4-sulfophenylamino} -9,10-Dihydro-9,10-dioxo-2-anthracenesulfonic acid disodium salt and 1-amino-4- {3 - [(4,6-dichloro-triazin-2-yl) -amino] 4-sulfo-anilino} -9,10-dihydro-9,10-dioxo-2-antracénszulfonsav.

The reaction conditions between the water-soluble halo-triazine dye which is essentially a monofunctional dye and the hydrophilic monomer will depend on the specific monomer chosen and the type of halotriazine dye used. These circumstances can be easily determined empirically.

A polymerizable dye is highly monofunctional when at least 50% of the polymerizable dye compounds formed as a result of the reaction contain only one reactive functional site as a result of the reaction of the hydrophilic monomer dye. If more than 50% of the polymerizable dye compound were difunctional, the dye would act as a crosslinking agent which would adversely affect the physical properties of the finished lens. Preferably, at least 80% of the polymerizable dye compounds are monofunctional. Ideally, at least 95% of the polymerizable paint is monofunctional.

The reaction between the monomer and the dye is preferably carried out in the presence of a base capable of solubilizing the monomer and the dye. The reaction can be accelerated towards completion of the reaction by adding the monomer in equimolar or molar excess. The reaction temperature is preferably raised above room temperature.

10, for example, are worked at 35-70 ° C for about 16-32 hours. Once the reaction is complete, the mixture is preferably neutralized to a pH of from 5 to 8. Excess reactants, solvents, or by-products may be removed from the reactive dye compounds by known methods.

The Lewis base solvent acts as an inert diluent in the reaction between the monomer and the dye. Suitable solvents include pyridine, tetrahydrofuran (THF) and dimethylsulfoxide (DMSO). However, the preferred solvent is an aqueous base, preferably an alkali metal or alkaline earth metal carbonate or phosphate.

As used herein, a soft hydrogel contact lens is a gel-like lens formed by the polymerization of a monomeric composition containing a hydrophilic monomer. By hydrophilic monomer is meant any monomer which, upon polymerization, produces a hydrophilic polymer which can be contacted with water to form a hydrogel. Examples of hydrophilic monomers include, but are not limited to, hydroxy esters of acrylic or methacrylic acid, N, N-dimethylacrylamide (DMA), N-vinylpyrrolidone (NVP), and styrylsulfonic acid, as well as those known in the art. other hydrophilic monomers. Subsequent polymeric lenses are formed by swelling a significant amount of water with the hydrogel lenses, the amount of water usually being greater than 30% and preferably at least 65%.

A preferred hydrophilic monomer is the hydroxy ester of acrylic acid or methacrylic acid. Examples of hydroxy esters of acrylic acid and methacrylic acid include, but are not limited to, hydroxyethyl methacrylate (HEMA), hydroxyethyl acrylate (HEA), ···· ······························ «· · · • •

- 11 glyceryl methacrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate and hydroxy trimethylene acrylate. Most preferred hydroxy esters of acrylic acid or methacrylic acid are HEMA, which is the most commonly used monomer for making soft hydrogel contact lenses.

Preferably, the hydrophilic monomer is copolymerized with comonomers in a monomer reaction mixture to achieve specific improvements in chemical and physical properties depending on the particular application desired. For example, the equilibrium water content of the lens can be increased by using methacrylic acid (MAA) as comonomer. In addition, relatively small amounts of multifunctional crosslinking monomers such as ethylene glycol dimethyl acrylate (EGDMA) and trimethylol propane trimethyl acrylate (TMPTMA) can be used in the reaction mixture to improve the dimensional stability and other physical properties of the lens. Similarly, other components may be added for specific applications, such as providing the UV absorbing property of the lens.

The monomeric reaction mixture also contains an initiator, typically about 0.05 to 1% of a free radical initiator, which can be thermally activated. Typical examples of the above initiators include lauroyl peroxide benzoyl peroxide, isopropyl percarbonate, azobis isobutyronitrile and known redox systems such as ammonium persulfate, sodium metabisulfite combination and the like. Ultraviolet light, electron beam or radioactive source may also be used to initiate the polymerization reaction, optionally with the addition of a polymerization initiator such as benzoin or its ethers.

• · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · • • • • · · · · · · · · · · · · · · · · · · · · · · · · · · · · everything · Like · |

The polymerization of the monomer reaction mixture is carried out after contacting the mixture with the desired amount of polymerizable dye and forming a homogeneous solution of the dye. The time needed to form a homogeneous solution can be easily determined empirically.

The polymerizable dye is added to the reaction mixture in an amount sufficient to provide the desired color or coloration of the lens. This amount, which can be determined empirically easily, depends on the thickness of the lens rim, the components of the reactive monomer mixture, and other factors.

The improved process of the present invention is preferably used to provide the lens with a coloring that renders the lens visible and easy to handle. This amount allows the wearer to visually notice if the lens is temporarily not applied during treatment, but should not be so large that the colored rim of the lens can be readily distinguished from the wearer's cornea during use. The amount of polymerizable dye added to the homogeneous solution prior to polymerization - which is the desired visibility! necessary to achieve coloration - depends on the purity of the dye added to the solution and should therefore be determined empirically. Generally, it may be present in an amount of from 0.01% to 0.35% by weight of the hydrophilic monomer, preferably from about 0.01% to about 0.2% by weight. The most preferred concentration range is about 0.05 to 0.15% by weight.

With the improved process of the present invention,

Thanks to the lens, accent coloring can also be provided. Accent coloring simply highlights the lens wearer's original eye color, for example, blue eyes look even more blue with accent lens coloring. The amount of polymerizable dye to be added to the homogeneous solution for emphasis coloration may conveniently be from about 0.35 to about 0.75% by weight of the hydrophilic monomer, preferably from about 0.35 to 0.50% by weight. The polymerization may be carried out in the presence or absence of an inert diluent. If the polymerization is carried out without diluent, the resulting polymeric composition may be formed, for example, by a sharp turning to the desired lens shape and then swollen with the required amount of water following the above procedure. Alternatively, and more preferably, the polymerization is carried out in the presence of a suitable inert diluent. A preferred inert diluent is a water displaceable boronic ester. The characteristics of the desired boronic acid esters as well as the preferred concentration of the ester in the polymerization reaction mixture are described in detail in U.S. Patent 4,680,336, the entire contents of which are incorporated herein by reference. Preferred methods of forming the desired lens when using a diluent include centrifugal molding and molding, such as those described in U.S. Patent 4,565,348, and combinations of the above with other methods generally described herein.

Once the polymerization reaction used to produce the lens has been satisfactorily completed, the lens can be hydrated to equilibrium water content. Preferably the water content of the lens is · ·

From about 35 to about 80% by weight, more preferably from about 55 to about 65% by weight. This range is ideal for long-term wear, when patient comfort and treatment characteristics are critical parameters.

The invention is further illustrated by the following non-limiting examples. Many other embodiments will be apparent to those skilled in the art, which are also within the scope of the invention.

The components used in the preparation of the contact lenses in the examples are abbreviated as follows: 2-hydroxyethyl methacrylate (HEMA), methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), boric ester of glycerol (0.16 mol boron / mol glycerol) ( GBAE), Ethoxylated Methyl Glucosidyl Aurate (MLE-80), Reactive Blue 4 [1-Amino- {4- [3- (4,6-dichloro-triazin-2-yl) -amino] -4-sulfoanilino } -9,10-dihydro-9,10-dioxo-2-anthracenesulfonic acid] (RB4), a dichlorotriazine dye, and hydroxy-α, of-dimethylacetophenone (Darocur 1173), a UV-reactive initiator . The HEMA used in each example is a high purity HEMA containing less than 0.1% by weight of impurities. The following tests were used to determine the physical and optical properties described in Table 1.

Oxygen permeability

The oxygen permeability through the lens is expressed as the Dk value multiplied by a factor having a 10 ^-11 cm ml02 / ml cis-mniHg unit. This was measured with a polarographic oxygen sensor consisting of a 4 mm diameter gold cathode and a silver-silver-chloride annular anode.

- 15 ·· «· ····

Tensile properties (modulus, elongation and strength)

The lens to be examined was cut to the desired size and shape and the cross-sectional area was measured. The sample was then fixed in the upper jaw of a constant velocity cross head motion tester equipped with a loading cell. The crosshead was lowered to the initial length and the sample was attached to the fixed clamp. The sample was then stretched at constant speed and the resulting stress-elongation curve recorded. Elongation is expressed as a percentage and the modulus of elongation and strength in psi (pound / square inch).

UV light transmission

This procedure may be used to determine the transmission of light through the lens. A light beam (200-800 nm) is passed through a quartz cuvette containing the lens in solution. The intensity of light emitted from the cuvette is measured and proportional to that of the reference beam. Values are expressed as% transmission.

color Stability

The lens was sterilized in an autoclave for 30 minutes and then qualitatively compared to a non-autoclaved lens for loss of color intensity. This procedure was repeated five times, and lenses that did not discolour were eligible for the assay.

Example 1

HEMA-bound RB4 reactive dye: Synthesis 1

Weigh 350 ml of 5% potassium into a 500 ml round-bottomed flask · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

- 16 - carbonate solution. HEMA (0.10 mol, 13.0 g) was added and the mixture was stirred for 10 minutes. To the resulting solution was added 0.08 mol (51.0 g) of RB4. After the paint has completely dispersed, the temperature is raised to 40-50 ° C. The reaction is monitored by chromatographic HPLC (Hanggi et al., 1985, Analytical Biochemistry 149: 91-104) to detect the reaction of chlorotriazine dyes with monofunctional alcohols. Using the above procedure, the formation of the monosubstituted monochlorotriazine-HEMA polymerizable dye is evident after about 42 minutes.

After 40-50 hours, a satisfactory conversion was achieved, whereupon the reaction mixture was filtered and the precipitate remaining on the filter was collected and dried. This precipitate can be applied to the color of the contact lenses itself. The filtrate can be evaporated in vacuo using a rotary evaporator to remove water from the reaction product. The remaining blue powder can be used to color the lenses. The inorganic compounds may be removed depending on the coloring requirements. Conversion of halo-triazine can be increased by reducing the amount of water in the reaction mixture. This will also increase the amount of duplex derivatives in the paint.

Example 2

HEMA-bound RB4 Reactive Dye: Synthesis 2

The reaction is performed as described below to give a monofunctional monochlorotriazine-HEMA polymerizable dye of about 85% purity. A limerizable dye with mechanical agitation is obtained. 2 L three-necked flask with mechanical stirring (cooled to 22 ° C before addition of reagents), 497.2 g. (27.62 moles) of water and 9.95 g (0.0721 moles) of potassium carbonate (Purity Purity, Aldrich 20261- 9) added. The solution was equilibrated at 22 ° C before the reagents were added. The reaction temperature must be monitored during the addition of the reagents. The pH of the above solution is maintained at 10-12. To the solution was added 497.2 g (3.82 moles) of high purity HEMA (containing 0.1263% EGDMA and 0.0275% MAA, Rhom Tech Mhoromer BM-920) at 22 ° C. Let C equilibrate. After adding a total of 76.5 g (0.120 mol) of RB4, the mixture was stirred for 30 minutes or until all lumps had dispersed. The reaction temperature was raised to 40 ° C and the disappearance of the RB4 peak was monitored by HPLC. When the RB4 peak is less than 3% of the total chromophobic peak area (about 170 hours), the mixture is neutralized to about 6.5-7.0 with dilute hydrochloric acid (40: 1). The mixture was stirred for 30 minutes and filtered. The precipitate remaining on the filter was transferred from the Buchner funnel to a vacuum desiccator and dried. The mortar and pestle filtrates may optionally be washed with diethyl ether, ethanol, acetone or methanol to remove organic impurities such as EGDMA, MAA or ethylene glycol.

Example 3

HEMA-bound RB4 reactive dye: Synthesis 3

To flask 1 was added 76.5 g RB4 and 450 g deionized water. Stir the contents of the flask at room temperature for 30 minutes. 497.5 g of hydroxyethyl methacrylate (HEMA) are added to the flask. Stir the contents of the flask for 20 minutes. 12.7 g of potassium carbonate in deionized water are added.

• · ···· ····

- 18 Heat the contents of the flask at 40 ° C for 96 hours. The mixture was neutralized to pH 6.5 with 2.5 N sulfuric acid. The contents of the flask were cooled for 24 hours at 5 ° C. The product was collected by vacuum filtration. The wet solid was suspended in a solution of 50 g deionized water and 100 g reagent ethyl alcohol. The product is recovered by vacuum filtration. The product obtained by washing as above was suspended in 100 g of reagent in ethyl alcohol and collected by vacuum filtration. The product thus obtained is dried at room temperature under a vacuum of less than 1 mm Hg.

The above synthesis gave 19.9 g of a blue powder which gave a single peak when analyzed by HPLC.

Example 4

HEMA-bound RB4 reactive dye: Synthesis 4

Flask 1 was charged with 75 g of RB4 and 572.5 g of deionized water. Stir the contents of the flask at room temperature for 30 minutes. 187.5 g of hydroxyethyl methacrylate (HEMA) are added to the flask. Stir the contents of the flask for 20 minutes. To the solution was added 11 g of 50% sodium hydroxide solution. The contents of the flask were stirred at room temperature for 1 hour. The mixture was neutralized to pH 6.5 with 2N sulfuric acid. The contents of the flask were cooled at 5 ° C for 24 hours. The product is recovered by vacuum filtration. The wet solid was suspended in a solution of 50 g deionized water and 100 g reagent ethyl alcohol. The product is recovered by vacuum filtration. The product of this wash is suspended in 100 g of reagent in ethyl alcohol and collected by vacuum filtration. The product thus obtained is dried at room temperature under a vacuum of 1 mm Hg.

·· ···· ····

19 The above synthesis gives 17.2 g of a blue powder which

It gives a single peak by HPLC analysis.

5, Ex

HEMA-bound RB4 Reactive Dye: Synthesis 5

9.0 g reactive black 5 (Remazol Black B, cas 17095-24-8) and 57.2 g deionized water were added to a 100 mL flask, and the contents were stirred at room temperature for 30 minutes. 18.7 g of hydroxymethyl acrylate are added to the flask. Stir the contents of the flask for 20 minutes. To the solution was added 1.0 g of 50% sodium hydroxide solution. The mixture was stirred at room temperature for 1 hour 20 minutes. The mixture was neutralized to pH 6.0 with 2.5 N sulfuric acid. The contents of the flask were cooled at 5 ° C for 24 hours. The product is recovered by vacuum filtration. The product was dried at room temperature under vacuum at a pressure of less than 1 mmHg. The product obtained in the synthesis was 0.52 g of a blue powder, which gave a single peak by HPLC analysis.

Preparation of High Water Color Tinted Contact Lenses A homogeneous mixture is prepared by mixing the following components: 58.08 parts HEMA, 0.71 parts EGDMA, 0.76 parts MAA, 0.14 parts Darocur 1173, 0.07 parts Polymerizable paint prepared according to Example 3. and 40 parts GBAE. The resulting mixture is polymerized in the form of contact lenses under UV light. After the polymerization is complete, the mold is opened and the molded lens is immersed in either 0.50% aqueous MLE-80 solution or 0.90% sodium chloride solution containing 0.50% MLE 80. The molds were placed in the above solutions at a temperature of 60-70 ° C. The colored lenses thus obtained are physical and optical ················································• · · «· · ··

Its properties are summarized in Table 1.

for comparison, the physical and optical properties of a tinted lens and a tinted lens by a known method are also shown in Table 1 as an example for control A and B. The colorless lens was prepared in substantially the same manner as described above except that no dye was used. The tinted lens of the prior art was prepared by first soaking the unstained lens in a RB4 solution containing 0.5% MLE-80 and then contacting the RB4 with the soaked lens by contacting it with an aqueous base before final hydration.

Table 1

Physical and optical properties of colored contact lenses

Properties Physical properties control Example B 1 . example Control The example Water content% 60 60 60 Oxygen permeability 28 26 28 Extensibility module, psi 36 36 34 Stretch% 120 118 128 Extensibility, psi 32 35 34

Optical properties

UV Transmittance Minimum% 85 85 85 Sz.íngtai? ILITA $ 5 Yes IGJ

·········· ·········································································································································································································································································, Once again, this will be working for you.

The results of Table 1 show that the physical and optical properties of the tinted contact lenses produced by the improved process of the present invention are substantially the same as those of the corresponding non-tinted lenses and the conventional process tinted contact lenses.

·· 4 4 * 4 ····

4 · ** ···· • · · «444 · • · · · 44« 444 · «44 4 4 ♦ ·

- 22 Patent claims

Claims (13)

Claims A process for the preparation of hydrophilic monomers comprising a water-soluble halo-triazine dye as a branching group, characterized in that: i) adding a base to an aqueous solution of a hydrophilic monomer; and ii) reacting the dye with the hydrophilic monomer; wherein the molar amount of base is greater than or equal to the molar amount of dye. 2. A process according to claim 1 wherein the hydrophilic monomer is hydroxy ester of acrylic acid or methacrylic acid. 3. The process according to claim 2, wherein the hydroxyl ester is HEMA. The process of claim 3, wherein the HEMA is used in the aqueous solution in an amount of about 10% to about 65% by weight. The process of claim 4, wherein the HEMA is used in an aqueous solution in an amount of from about 25% to about 40% by weight. 6. The process of claim 1, wherein the base and dye are used in an equimolar amount. The process of claim 1, wherein the molar ratio of base to dye is approximately 2: 1. The process of claim 1, wherein the molar ratio of base to dye is approximately 3: 1. The method of claim 1, characterized by: ·········································· · · · · · · · · · · · · · · · ··· ·· · «·· ·· 23, wherein the halo-triazine dye is a dihalo-triazine dye. 10. The process according to claim 7, wherein the dichlorotriazine dye is at least one sulfonate functional group. 11. The method of claim 8 wherein the dichlorotriazine dye is Color Index Reactive Blue 4. 12. A process for the preparation of hydrophilic monomers comprising a water soluble vinyl sulfone dye as a branching group, characterized in that: i) adding a base to an aqueous solution of a hydrophilic monomer; and ii) reacting the dye with the hydrophilic monomer; wherein the molar amount of base is greater than or equal to the molar amount of dye. 13. Hydrophilic monomer dye unit, having at least 85% chromatographic purity. 13. Hydrophilic monomer dye unit with 100% chromatographic purity. The agent shall: DANUBIA Patent and Trademark Office Ltd.