JPH071352B2 - Marking method for soft contact lenses - Google Patents

Description

TECHNICAL FIELD The present invention relates to a soft contact lens marking method, and more particularly to a method capable of sharply marking a high water content soft contact lens.

(Prior art) Conventionally, soft contact lenses have been made clear by distinguishing the front and back and distinguishing between left and right lenses when they become soft by absorbing water.
For the purpose of facilitating the arrangement, desired marks such as letters and symbols are provided, and for example, together with a hydrophilic monomer such as hydroxyethyl methacrylate, a color reaction with a diazo component is caused. By copolymerizing a coupler material, a contact lens material containing the coupler material in advance, and after molding the lens, it is immersed in an aqueous solution of diazo to cause a coupling reaction to develop a color, A coupling method is known in which a required mark is provided.

Further, in JP-A-53-13673, JP-A-53-114876, JP-A-54-58508, etc., a desired mark is imprinted on a contact lens using a solution of a photosensitive dye, Thereafter, a printing method has also been clarified in which the dye is irradiated with ultraviolet rays or the like to make the dye insoluble in water and develop a color. As the dye used in this printing method, a photosensitive soluble vat dye is used from the viewpoint of fastness and the like.

(Problem) However, in these conventional marking methods,
Both of them have considerable problems. For example, in the case of marking by the above coupling method, it is necessary to give a coloring component to a portion other than the required mark portion. There are inherent defects such as discoloration of marks and marks.

Further, in the marking by the above printing method, when a desired mark is printed on the soft contact lens in the swollen state, bleeding of the dye occurs, and the printed characters and symbols lack sharpness (visibility). The problem is inherent.
This is because water-soluble dyes, especially water-soluble vat dyes, are used as the dyes to be used, so that the dyes permeate and diffuse into the swollen contact lens. Therefore,
This printing method is not always satisfactory as a method for imparting very fine marks, letters and other marks required for contact lenses.

And sharpness (sharpness) for such characters and symbols
Marking lacking in water is especially high in water content
This is remarkable in 40% or more of soft contact lenses.

(Solution) Here, the present invention has been made to solve such a conventional problem, and is characterized in that a high water content soft contact lens having a water content of 40% or more is provided. , After immersing in a salt solution with a concentration of 1/3 or more of the saturated concentration and allowing the salt solution to penetrate into the lens,
For the obtained soft contact lens in the swollen state,
Marks such as required letters, symbols, etc. were given using a soluble vat dye, and then the vat dye was made to develop color, thereby causing a clear marking without causing problems such as bleeding of the dye. It was possible to do it.

(Operation / Effect) As described above, in the present invention, the water content of 40% is set before the predetermined marking is performed using the predetermined vat dye.
% Or more of water-containing soft contact lens is dipped in a high-concentration salt solution, and the desired marking is performed under the condition where the salt solution is allowed to penetrate into the lens, so that characters and symbols can be displayed. Although the sharpness of the mark is markedly improved, the mechanism of action of the pretreatment with such a high-concentration salt aqueous solution has not been sufficiently clarified.

However, according to the inventor's speculation, due to the presence of a high concentration of salts in the swollen soft contact lens, the vat dye is dissolved in water due to the magnitude of so-called salt breakage or ionization tendency in the lens. It is a state where it is deposited from the inside, which suppresses its diffusion in the lens, and thus prevents the dye bleeding well,
It is believed that the sharpness of the mark will be improved.

(Specific Description of Structure) In the present invention, in order to advantageously improve the bleeding of the dye and the sharpness of the mark, a high-concentration aqueous solution of a salt of an inorganic salt or an organic salt is used, and the hydrous soft contact is used. The lens needs to be processed. This is because, if the salt concentration is low and effective precipitation of the dye in the lens cannot be expected. In order to effectively precipitate such a dye, it is necessary to use it as an aqueous solution having a concentration of about 1/3 or more of the saturated concentration of the salt used. In addition,
If the salt concentration in the aqueous solution is brought close to its saturation concentration, the dye will appear to precipitate with almost any salt, but the higher the concentration, the more marked the change in lens size, and the precipitation of salt. Therefore, it is rather difficult to make the mark clear, so in actual use, it is preferable that the saturated concentration is around 2/3 of the saturated concentration, and generally within the range of 1 / 3-3 / 3 of the saturated concentration, especially 1 / 2-5.
A concentration within the range of / 6 will be preferably adopted.

Further, the salt constituting the aqueous salt solution is appropriately selected from inorganic salts and organic salts, and is represented by the general formula: MnXm (where M is an alkali metal such as Na or K, Ca or Ba).
Alkaline earth metals such as, or NY ₄ groups such as ammonium and tetraalkylammonium (Y is hydrogen or an alkyl group having 1 to 3 carbon atoms), X is Cl, Br,
Halogen such as I, SO ₄ ²⁻ , CO ₃ ²⁻ or organic acid ion such as citric acid or acetic acid, and n and m are 1 or 2 respectively.
Will be used.
Of course, these inorganic salts or organic salts have a property of being well soluble in water, and specifically, they are BaCl ₂ , CaBr ₂ , CaCO ₃ , CaC.
_{l 2, MgBr 2, MgCl 2} , NH 4 Cl, NaBr, NaCl, Na 2 CO 3, NaI,
Examples thereof include Na ₂ SO ₄ , KCl, KBr, KI, K ₂ SO ₄ , trisodium citrate, and sodium acetate. Among them, KCl, NH ₄ Cl, NaCl and the like are particularly preferably used because of the characteristics such as the ease of precipitation of the dye, the easy availability, and the effect at a low concentration.

Further, according to the present invention, the hydrous soft contact lens which is subjected to the immersion treatment in such a high-concentration aqueous salt solution has a hydrophilic monolayer such as N-vinylpyrrolidone or hydroxyethylmethacrylate as well known in the art. A water-containing soft contact lens obtained from a hydrophilic resin containing a monomer as a main component, and particularly in the present invention, a high water content soft contact lens having a water content of 40% or more, preferably 60% or more. It is applied to and exerts an excellent effect. In addition, such a hydrous soft contact lens is soaked in a predetermined high-concentration salt aqueous solution in a dry state not swollen with water, and physiological saline is previously prepared before such an immersion treatment. There is no problem even if it is made to swell with water or the like and then immersed in the above-mentioned predetermined aqueous salt solution.

Then, by such immersion treatment in a high-concentration predetermined salt aqueous solution, such a salt aqueous solution is permeated into the hydrous soft contact lens, and the soft contact swollen with such a salt aqueous solution. A lens is obtained, and such a soft contact lens is subjected to a conventional marking operation using a predetermined soluble vat dye.

By the way, examples of the soluble vat dye used in such marking operation include soluble vat yellow 3 (CI.61726) and soluble vat yellow 4 (CI.591).
01), Soluble Butt Yellow 7 (CI.60531), Soluble Butt Yellow 8 (CI.60606), Soluble Butt Red 1 (CI.73361), Soluble Butt Red 2 (CI.7336).
6), Soluble Vat Red 10 (CI.67001), Soluble Vat Blue 2 (CI.73046), Soluble Vat Blue 5
(CI.73066), Soluble Vat Blue 8 (CI.73801),
Soluble Vat Black 1 (CI.73671), Soluble Vat Black 6 (CI.73661), Soluble Vat Violet 8 (CI.73601) and the like can be mentioned.

In addition, when applying a predetermined marking to a contact lens in a swollen state using such a soluble vat dye, after removing water etc. adhering to the lens surface with Kimwipe (manufactured by Tojo Kimberley Co., Ltd.), imprinting or silk A mark such as a desired character or symbol is provided at a predetermined position on the lens by a method such as screen printing.

More specifically, in the screen printing method preferably used in the present invention, a silk screen provided with a pattern of required characters, symbols, etc. is placed so as to be in contact with the contact lens in a swollen state. Then, a dyeing solution consisting of the above-mentioned aqueous solution of soluble vat dye is applied. The silk screen used at this time is preferably made of a material such as nylon or polyester that has a mold corresponding to the required characters and symbols, and the number of lenses that can be processed depends on the number of lenses that can be processed. It is possible to carry out a large amount of marking at a time by providing a mold of the corresponding character, symbol, etc. in the portion that contacts with.

Then, after the desired mark is formed on the contact lens in this way, color development processing such as oxidation processing is further applied,
The vat dye (mark) is colored and dyed. Examples of this oxidation treatment method include a method of air oxidation under UV irradiation. It should be noted that this UV irradiation may be performed for a short time from above the silk screen with an exposure device.For example, using a UV lamp of 350 to 380 nm, UV irradiation may be performed for a predetermined time according to each dye. Become.

The contact lens provided with the predetermined mark thus obtained does not have the bleeding of the used vat dye, is sharply provided with letters and symbols, and can be used for a long time, and has a commercial value. It is expensive.

(Examples) Hereinafter, several examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is subject to any restrictions by the description of such examples. Needless to say, it is not a thing. The ratios and percentages in the examples are based on weight.

Further, the present invention is not limited to the following embodiments, and in addition to the above specific description, various changes, modifications, improvements and the like based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that can be added.

Example 1 A water-containing soft contact lens (water content: 78%) made of N-vinylpyrrolidone-based hydrophilic resin was mixed with 14.7% KCl.
The water contained in the lens was completely replaced with the KCl aqueous solution by immersion in the aqueous solution for 5 minutes or more. Then, the lens was taken out and wiped with Kimwipe so that no water droplets remained on the lens surface, and it was firmly fixed under the silk screen. Then, 3.8% soluble Bat Black 1 (Anthrasol Gray IBL, West Germany: Hoechst) aqueous solution was gently sprayed on the screen using a high performance airbrush handpiece (HP-101 type manufactured by Olympus), and 10 as it was. After leaving it for a minute to dry on the screen, the lens was taken out, and then the dye was insolubilized and colored by irradiating with ultraviolet rays (355 nm) for 5 minutes.

It was confirmed that the soft contact lens subjected to the marking operation had almost no dye bleeding and had a clear mark.

On the other hand, when the predetermined marking was performed by the same marking operation as above without immersing the above soft contact lens in the KCl aqueous solution, the dye bleeds over the entire lens, and it was not possible to clearly dye only the letters. .

Example 2 Instead of the soluble vat dye in Example 1, soluble vat red 2 (Anthrasol Brill.Pink I3B, West Germany:
Hoechst) 2.5% dye solution, Soluble Vat Blue 5 (Anthrasol O4BS, West Germany: Hoechst) 1.9
% Dye solution or soluble vat blue 8 (Anthraso
Using a 1.9% dye solution (Blue AGG, West Germany: Hoechst), a marking operation was performed in the same manner as in Example 1 to obtain a soft contact lens having a very sharp mark.

Example 3 Using a water-containing soft contact lens (water content: 63%) made of N-vinylpyrrolidone-based hydrophilic resin and using a 22.2% concentration NH ₄ Cl aqueous solution, With respect to the dyes, the marking operation in each of the examples was carried out to obtain a soft contact lens in which all the dyes were beautifully marked.

Comparative Example 1 Using the hydrous soft contact lens of Example 1, it was immersed in physiological saline (0.9% NaCl aqueous solution) for 10 minutes to replace the water in the lens with saline. Then, the lens was taken out, the surface was wiped, and it was fixed under a predetermined silk screen. Then, 3.8% of soluble Bat Black 1 aqueous solution was gently sprayed on the screen using an airbrush handpiece, the screen was dried by a dryer, and then the lens was taken out and then irradiated with ultraviolet rays for 5 minutes. , Insolubilize the dye,
I made it color.

By this marking operation, a mark was given on the soft contact lens, but without impregnating the physiological saline solution, just like the case where the lens is simply impregnated with distilled water, the dye bleeds throughout, It was not possible to clearly color only the letters.

Comparative Example 2 The same hydrous soft contact lens as in Example 1 was used, and it was immersed in ethanol for 10 minutes to replace the water in the lens with ethanol. Then, the lens was taken out, the surface was wiped and fixed under a predetermined silk screen, then 3.8% soluble Bat Black 1 aqueous solution was lightly sprayed from above the screen using an airbrush handpiece, and further dried on the screen by a dryer. After that, the lens was taken out, and then the dye was insolubilized and colored by irradiation with ultraviolet rays for 5 minutes.

In the case of the soft contact lens that has been subjected to such an operation, it is considered that the dye has completely diffused into the lens, which causes color development throughout the lens, making it impossible to perform the intended marking at all. It was

Comparative Example 3 Marking was performed in the same manner as in Example 1 except that the lens was immersed in a mixed solvent having a mixing ratio of water: ethanol: glycerin = 8: 1: 1 (10 minutes). As a result, the mark was added to the lens, but it was not possible to clearly stain only the letters by bleeding over the entire surface.

Claims (3)

[Claims] 1. A high water content soft contact lens having a water content of 40% or more is immersed in a salt aqueous solution having a concentration of ⅓ or more of a saturated concentration to allow the salt aqueous solution to penetrate into the lens. The obtained swollen soft contact lens is provided with a mark such as a required character or symbol using a soluble vat dye, and then the vat dye is colored, which is a method for marking a soft contact lens. . 2. The aqueous salt solution has the general formula: MnXm [wherein
M is an alkali metal, alkaline earth metal or NY ₄ group (Y
Is hydrogen or an alkyl group having 1 to 3 carbon atoms), X is halogen, SO ₄ ²⁻ , CO ₃ ²⁻ or an organic acid ion, and n and m are 1 or 2, respectively.] The method for marking a soft contact lens according to claim 1, which is an aqueous solution containing the inorganic salt or organic salt represented. 3. The marking method for a soft contact lens according to claim 1 or 2, wherein the vat dye is colored by ultraviolet irradiation.