JPH09146050A - Method for dyeing lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for dyeing lenses capable of improving the dyeability of plastic lenses and prolonging the pot life of a dyeing bath without staining the lenses by previously impregnating the plastic lenses with an aq. dyeing assistant soln. to penetrate the dyeing assistant in the lens surface and attracting the dye to the assistant. SOLUTION: Plastic lenses are first impregnated with an aq. dyeing assistant soln. The lenses pulled up from the bath after the impregnation with the aq. dyeing assistant soln are washed with water and dried and, thereafter, the lenses are subjected to dyeing, i.e., dip dyeing in the dyeing bath. The dip dyeing is executed by dispersing a dispersion dye and surfactant into water or a mixture composed of water and an org. solvent to prepare the dyeing bath, immersing the plastic lenses into this dyeing bath and dyeing the lenses for a prescribed time at a prescribed temp. The dyeing assistant is previously made to penetrate into the lens surfaces in such a manner and the dye is attracted to the assistant, thereby, the dye adsorption to the lenses is accelerated.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for dyeing a plastic lens for eyeglasses.

[0002]

2. Description of the Related Art Conventionally, plastic lenses for eyeglasses are dyed from the viewpoint of their fashionability, etc.
We give half dyeing. However, since plastic lenses are difficult to dye, dyeing is performed by adding a dyeing aid to a dyeing bath in order to improve dyeing properties.
However, dyeing baths containing dyeing aids tend to cause evaporation of dyeing aids and dyes, and because the dyeing aids accelerate sublimation and evaporation of dyes, their pot life is short and hue control is also possible. There is a problem that the lens is difficult to be stained, and the lens is easily contaminated during dyeing, especially half dyeing.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for dyeing a lens which improves the dyeability of a plastic lens, does not contaminate the lens and can extend the pot life of the dye bath. And

[0004]

According to the present invention, a plastic lens is previously impregnated with an aqueous dyeing aid solution, the dyeing aid is permeated into the lens surface, and the dye is attracted to the aid to adsorb the dye on the lens. The above problems have been solved by promoting the above. That is, the method for dyeing a lens of the present invention is characterized in that a plastic lens is impregnated with an aqueous solution of a dyeing aid, and then immersed in a dyeing bath containing no dyeing aid for dyeing.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the plastic lens is not particularly limited, and the plastic lens base is made of various plastic lens materials such as diethylene glycol bisallyl carbonate polymer, polyurethane resin, acrylic resin, polycarbonate resin and polystyrene. May be something.

In the method of the present invention, a plastic lens is first impregnated with an aqueous dyeing aid solution. As the dyeing aid, any of those conventionally added to a dyeing bath can be used, and examples thereof include alkylnaphthalene-based compounds such as methylnaphthalene, diphenyl, diphenyl-based compounds such as o-phenylphenol, trichlorobenzene, and dichlorobenzene. Examples include chlorobenzene, chlorobenzene, and other chlorobenzene-based, and ethylene glycol, benzyl alcohol, and other alcohol-based auxiliary agents, and one or more of these may be used. The concentration of the dyeing aid in the aqueous dyeing aid solution is 0.
It is preferably 3 to 3.0% by weight, more preferably 0.5 to 2% by weight. When the concentration of the dyeing aid is less than 0.3% by weight, the effect of promoting the dye adsorption is not sufficiently obtained, and when it exceeds 3% by weight, the surface of the plastic lens may be damaged.

When the dyeing assistant is insoluble or hardly soluble in water, it is emulsified using an emulsifier such as an alkali soap, an organic amine soap, a sulfate of a higher alcohol, or a synthetic surfactant.

[0008] The aqueous solution of the dyeing aid is heated to a temperature of 95 ° C or lower, preferably 80 to 95 ° C. By heating the aqueous solution of the dyeing aid in this way, the dyeing aid can easily penetrate into the immersed plastic lens. If the temperature exceeds 95 ° C., evaporation will be severe and the stability of the aqueous solution will be poor. The impregnation with the dyeing aid aqueous solution is carried out by immersing the dyeing aid solution in an aqueous solution having the above dyeing aid concentration at a temperature of 95 ° C. or lower for several minutes to several tens of minutes.

After the lens is impregnated with the dyeing auxiliary solution, the lens taken out from the bath is washed with water, dried, and then dyed in the dyeing bath, that is, dip dyeing is performed. The dye used in the present invention is not particularly limited, but a dye having high fastness is preferable.
For example, anthraquinone dye, quinophthalone dye,
Disperse dyes such as nitrodiphenylamine dyes and azo dyes can be used. Specific examples of the disperse dye include p-anisidine, aniline, p-aminoacetanilide, p-aminophenol, 1-chloro-2,4.
-Dinitrobenzene, 2-chloro-4-nitroaniline, o-chloronitrobenzene, diphenylamine, m
-Nitroaniline, p-nitroaniline, N, N-bis (2-hydroxyethyl) aniline, 1-phenyl-3
-Methyl-5-pyrazolone, benzene-based intermediates such as phenol, p-cresidine (6-methoxy-m-toluidine), m-cresol, p-cresol, m-toluidine, 2-nitro-p-toluidine, p- Toluene-based intermediates such as nitrotoluene, 1-naphthylamine, naphthalene-based intermediates such as 2-naphthol, 1-amino-4-bromoanthraquinone-2-sulfonic acid (bromamic acid),
1-anthraquinonesulfonic acid, 1,4-diaminoanthraquinone, 1,5-dichloroanthraquinone, 1,4
-Dihydroxy anthraquinone (quinizarin), 1,5
-Dihydroxyanthraquinone (anthralphin),
Examples thereof include phthalic anhydride such as 1,2,4-trihydroxyanthraquinone (purpurin) and 2-methylanthraquinone, and anthraquinone-based intermediates. The disperse dyes may be used alone or in combination of two or more. The disperse dye is usually dispersed in water to form a dyeing bath, but an organic solvent such as methanol, ethanol or benzyl alcohol may be used together as a solvent.

A surfactant may be added to the dye bath as a dispersant for the dye. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonate, alkylnaphthalene sulfonate, alkylsulfosuccinate, aromatic sulfonic acid formalin condensate, and lauryl sulfate, polyoxyethyl alkyl ether, and alkyl. Examples thereof include nonionic surfactants such as amine ethers and polyoxyethylene sorbitan fatty acid esters. These surfactants are used in an amount of 5 to 200% based on the amount of the dye used, depending on the coloring density of the lens.
It is preferred to use in the range of weight%. In the dip dyeing, a disperse dye and a surfactant are dispersed in water or a mixture of water and an organic solvent to prepare a dyeing bath, a plastic lens is immersed in the dyeing bath, and dyeing is performed at a predetermined temperature for a predetermined time. The dyeing temperature and time vary depending on the desired color density,
Usually, it may be several minutes to 30 minutes at 95 ° C. or less. Further, the dye concentration of the dyeing bath is preferably 0.01 to 5% by weight. The plastic lens dyed as described above is dyed well, and the hard coat film and / or the antireflection film can be formed thereon by a known method.

[0011]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto.

Example 1 20 g of methylnaphthalene and a surfactant (manufactured by Nichika Chemical Co., Ltd.,
10 g of sun salt 7000) was dissolved in 1 liter of water, and a polyurethane resin lens (Asahi Optical Co., Ltd., trade name Asmore) was immersed in a dyeing aid aqueous solution heated to 90 ° C. for 10 minutes, and the taken out lens was washed with water, After drying, dyeing was carried out at 80 ° C. for 10 minutes in the following dyeing bath (gray mixture). Sumikaron Blue S-RPD (Sumitomo Chemical) 2g Sumikaron Red S-RPD (Sumitomo Chemical) 2g Sumikaron Yellow S-RPD (Sumitomo Chemical) 4g Water 1 liter

Example 2 16 g of dichlorobenzene and a surfactant (manufactured by Nichika Chemical Co., Ltd.,
10 g of sun salt 7000) was dissolved in 1 liter of water, and a polyurethane resin lens (Asahi Optical Co., Ltd., trade name Asmore) was immersed in a dyeing aid aqueous solution heated to 90 ° C. for 10 minutes, and the taken out lens was washed with water, After drying, the dyeing bath used in Example 1 was dyed at 80 ° C. for 10 minutes.

Comparative Example 1 A polyurethane resin lens (trade name: Asmore, manufactured by Asahi Optical Co., Ltd.) was immersed in the dyeing bath used in Example 1 as it was, and dyeing was carried out at 80 ° C. for 10 minutes.

Comparative Example 2 To the dyeing bath used in Example 1, 2% by weight of methylnaphthalene and 1% by weight of a surfactant (Nichika Kagaku Co., Ltd., Sun Salt 7000) were added, and the resulting dyeing bath was untreated. Dip a polyurethane resin lens (Asahi Optical Co., Ltd., trade name Asmore),
Dyeing was carried out at 80 ° C. for 10 minutes.

Comparative Example 3 To the dyeing bath used in Example 1, 2% by weight of dichlorobenzene and 1% by weight of a surfactant (Nichika Kagaku Co., Ltd., Sun Salt 7000) were added, and the resulting dyeing bath was untreated. Immerse a polyurethane resin lens (made by Asahi Optical Co., Ltd., trade name Asmore)
Dyeing was carried out at 80 ° C. for 10 minutes.

The dyeing density (transmittance) of the lenses obtained in each of the Examples and Comparative Examples and the stains on the lenses at the time of half dyeing were observed, and the results are shown in Table 1. Further, the pot lives of the dyeing auxiliary solution and the dyeing bath were examined, and the results are shown in Table 1. In addition, the dyeing density is measured by Hitachi's own recording spectrophotometer U.
-3210, and the dirt of the lens was visually observed.

[0018]

[Table 1]

[0019]

EFFECTS OF THE INVENTION According to the present invention, the dyeing aid that has been permeated into the lens in advance attracts the dye in the subsequent dyeing process, so that the dye adsorption to the lens is promoted and the lens can be dyed easily, and As compared with the conventional method in which the agent is added to the dyeing bath, the lens does not become dirty and the pot life of the dyeing bath is significantly extended.

Claims (6)

[Claims] 1. A method for dyeing a lens, which comprises immersing a plastic lens in an aqueous solution of a dyeing aid, and then immersing the lens in a dyeing bath containing no dyeing aid for dyeing. 2. The method for dyeing a lens according to claim 1, wherein the dyeing aid aqueous solution is an aqueous solution containing 0.3 to 3% by weight of the dyeing aid. 3. The method for dyeing a lens according to claim 1, wherein an aqueous dyeing aid solution heated to a temperature of 95 ° C. or lower is used. 4. The method for dyeing a lens according to claim 1, wherein the dyeing aid is at least one selected from alkylnaphthalene type, diphenyl type, chlorobenzene type and alcohol type. 5. The dye concentration of the dyeing bath is 0.01 to 5% by weight.
The method for dyeing a lens according to claim 1, wherein 6. The method for dyeing a lens according to claim 1, wherein the temperature of the dyeing bath is 95 ° C. or lower.