JP2009058570A - Dyeing method of plastic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dyeing method of a plastic lens by which the adhesion of a deposit on a lens surface does not arise and the occurrence of color unevenness is suppressed. <P>SOLUTION: The dyeing method of the plastic lens comprises dyeing the thiourethane-based plastic lens by immersing the lens into a dyeing liquid which contains a disperse dye, 2-ethyl hexyl sulfate sodium salt as a surfactant in the range of 1 to 30 ml per 1 litter water and, as a dyeing carrier, at least one or more kinds of compounds selected from among phenols, such as p-phenyl phenol, m-phenyl phenol, o-phenyl phenol, cinnamyl alcohol, and benzyl alcohol or alcohols having aromatic rings. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plastic lens dyeing method in which a plastic lens is immersed in a dyeing solution for dyeing.

In recent years, plastic lenses have been used in many fields including eyeglass lenses and camera lenses. The easy coloring is one of the greatest advantages of the spectacle lens. At present, for coloring plastic lenses, a dyeing method is used in which a disperse dye is dissolved and dispersed in warm water or an organic solvent, and the plastic lens is immersed therein.
As such a dyeing method, a lens is dyed by immersing a plastic lens in a dyeing solution (dyeing bath) containing a disperse dye and a surfactant in warm water of about 85 ° C. to 95 ° C. Yes. At this time, the surfactant helps to disperse the disperse dye in water and has an effect of uniformly dispersing the disperse dye.

  In addition, plastic lenses have been increased in refractive index in order to meet the demand for thinning, and thiourethane lens materials having a refractive index of 1.60 or more are widely used. When dyeing such a thiourethane plastic lens, a dyeing carrier is further added because a dyeing solution containing only a disperse dye and a surfactant has a low dyeing speed (Patent Document 1). ,reference).

Japanese Patent Laid-Open No. 11-12959

However, in the case of dyeing a plastic lens using a dyeing solution to which a dyeing carrier is added, a disperse dye or a mixture of a disperse dye and a dyeing carrier often adheres to the dyed lens surface (described later). (See FIG. 2).
This deposit cannot be removed by washing with water, but can be removed from the lens surface by wiping the lens surface with paper containing acetone, ethanol, or the like. However, in order to remove all deposits cleanly without remaining on the surface of the lens, it takes a lot of time and man-hours such as changing and wiping the paper several times. In addition, when the amount of deposits is small, the effect on appearance performance such as color unevenness is small, but when a long dyeing time such as dark dyeing is required, such as plastic eyeglass lenses for sunglasses. It is a factor that deteriorates the appearance performance such as uneven dyeing by adhering in large amounts.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The plastic lens dyeing method according to this application example is a plastic lens dyeing method in which a plastic lens is colored by immersing the plastic lens in a dyeing solution, and the dyeing solution contains a disperse dye, a dyeing carrier, a surfactant, The surfactant is 2-ethylhexyl sulfate sodium salt represented by the following general formula (1).

According to this, the dyeing solution for dyeing a plastic lens contains 2-disperse dye, a dyeing carrier, and a surfactant, and the surfactant is 2-ethylhexyl sulfate sodium salt represented by the general formula (1). As a result, the dispersibility of the disperse dye in the dyeing solution is improved, and the disperse dye or the mixture of the disperse dye and the dye carrier can be prevented from adhering to the lens surface. In addition, the dyeing speed of the plastic lens can be sufficiently ensured by not reducing the affinity between the disperse dye and the plastic lens. Therefore, it is possible to obtain a dyeing method capable of exhibiting sufficient dyeability and dyeing stability, and to avoid operations such as dropping the deposits.

[Application Example 2]
In the plastic lens dyeing method according to the application example described above, the content of the 2-ethylhexyl sulfate sodium salt is preferably in the range of 1 ml to 30 ml per liter of water.
According to this, the content of 2-ethylhexyl sulfate sodium salt (surfactant) represented by the general formula (1) contained in the staining liquid is in the range of 1 ml to 30 ml per liter of water. Thus, the dispersibility of the disperse dye in the dyeing liquid is improved, and the disperse dye or the mixture of the disperse dye and the dye carrier can be prevented from adhering to the lens surface. When the content of 2-ethylhexyl sulfate sodium salt is less than 1 ml, a large amount of the disperse dye or a mixture of the disperse dye and the dye carrier is generated on the lens surface. On the other hand, if it exceeds 30 ml, there is no adhesion to the lens surface, but uneven dyeing of the plastic lens occurs.

[Application Example 3]
In the plastic lens dyeing method according to the application example, it is preferable that the plastic lens is a thiourethane plastic lens.
According to this, the dyeing solution for dyeing a plastic lens contains 2-disperse dye, a dyeing carrier, and a surfactant, and the surfactant is 2-ethylhexyl sulfate sodium salt represented by the general formula (1). As a result, a thiourethane plastic lens having a refractive index of 1.60 or more can be easily dyed. That is, a high refractive index plastic lens can be easily dyed.

[Application Example 4]
In the plastic lens dyeing method according to the application example described above, the dyeing carrier is preferably at least one compound selected from phenols or alcohols having an aromatic ring.
According to this, the dyeing liquid containing 2-ethylhexyl sulfate sodium salt (surfactant) represented by the above general formula (1) is selected from phenols or alcohols having an aromatic ring as a dyeing carrier. By including at least one kind of compound, it is possible to suppress adhesion of deposits on the lens surface and improve the dyeing speed. Further, a plastic lens dyed with a good lens appearance without color unevenness can be obtained.

[Application Example 5]
In the method for dyeing a plastic lens according to the above application example, the phenol or the alcohol having an aromatic ring is preferably p-phenylphenol, m-phenylphenol, o-phenylphenol, cinnamon alcohol, or benzyl alcohol.
According to this, the dyeing carrier contained in the dyeing liquid may be any of p-phenylphenol, m-phenylphenol, o-phenylphenol, cinnamon alcohol, phenols of benzyl alcohol or alcohols having an aromatic ring. In addition, it is possible to suppress the adhesion of deposits to the lens surface and improve the dyeing speed. Further, a plastic lens dyed with a good lens appearance without color unevenness can be obtained.

Hereinafter, embodiments will be described.
The plastic lens dyeing method according to the present embodiment is preferably used for a plastic lens (hereinafter referred to as a lens) made of a thiourethane plastic lens material (thiourethane resin) obtained by reacting an isocyanate compound and a polythiol compound. Can do. A lens made of thiourethane resin can obtain a high refractive index lens having a refractive index of 1.60 or more.

  Conventionally, a lens made of an allyl plastic lens material such as CR-39, which has been widely used, can be easily dyed using a dyeing liquid to which a disperse dye and a surfactant are added without using a dyeing carrier. However, for dyeing a lens made of a thiourethane resin, a dyeing liquid obtained by adding a disperse dye, a surfactant and a dyeing carrier to water is often used. The refractive index of CR-39 is about 1.50.

  As the disperse dye, a blue dye such as anthraquinone or azo, a red dye, a yellow dye, or a brown dye is used. These disperse dyes may be used alone or in combination of two or more so that they can be dyed in a desired color. Although disperse dyes are hardly soluble in water, the addition of a surfactant makes it possible to uniformly disperse and soak evenly immersed plastic lenses in water.

  As the surfactant, 2-ethylhexyl sulfate sodium salt represented by the following general formula (1) is used. As a specific example, Shintrex (registered trademark) EH-R made by NOF can be exemplified.

This surfactant improves the dispersibility of the disperse dye in the dyeing solution (dye bath) and prevents the disperse dye or the mixture of the disperse dye and the dye carrier from adhering to the lens surface. By suppressing the decrease in the affinity, it is possible to obtain an effect of preventing the lens dyeing speed from decreasing. Hereinafter, a disperse dye or a mixture of a disperse dye and a dye carrier adhering to the lens surface may be referred to as an adhering substance or a surface adhering substance.

  Incidentally, conventionally used alkyl sulfate sodium salt, alkyl ether sulfate sodium salt, polyoxyethylene alkyl ether sulfate sodium salt, polyoxyethylene alkyl ether sulfate triethanolamine salt, polyoxyethylene alkyl. Surfactants such as ether sulfate, sodium alkylbenzene sulfonate, polyethylene glycol lauryl ether, polyethylene glycol cetyl ether, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol lauryl amine, polyethylene glycol stearyl amine are added in small amounts. In this case, the dispersibility is insufficient, and deposits are generated on the dyed lens surface. Further, when added in a large amount, the dispersibility is improved, but there is a drawback that the dyeing speed of the lens is lowered. These surfactants are presumed to reduce the dyeing speed when added in a large amount by reducing the affinity between the disperse dye and the lens surface.

  As the dyeing carrier, phenols or alcohols having aromatic rings (aromatic alcohols) are used. Specific examples of phenols include p-phenylphenol, o-phenylphenol, m-phenylphenol, p-chlorophenol, o-chlorophenol, m-chlorophenol and the like. Examples of aromatic alcohols include benzyl alcohol and cinnamon alcohol. Such a dyeing carrier has the effect of improving the dyeing speed.

A dyeing solution for dyeing plastic lenses is used by adding these disperse dyes, surfactants and dyeing carriers to water.
About 1 ml to 30 ml of a surfactant of 2-ethylhexyl sulfate sodium salt represented by the above general formula (1) is added to warm water in which 1 liter of water is heated to about 90 ° C. to 95 ° C., and further dyeing is performed. The dyeing solution is completed by adding about 0.01 g to 10 g of one or two or more disperse dyes according to a predetermined color tone and about 1 g to 10 g of a dyeing carrier such as p-phenylphenol.

The lens is colored by immersing the plastic lens in this staining solution. The immersion time of the lens varies depending on the dyeing density to be dyed, and is about 10 seconds to 10 minutes for light coloring and about 10 minutes to 10 hours for dark coloring.
Then, the colored lens is pulled up from the dyeing solution, and then immersed in water at about 10 ° C. to 30 ° C. to be washed with water and cooled.

  Then, the lens surface is wiped with a paper soaked with an organic solvent such as acetone or ethanol, and it is checked whether there are any appearance defects such as color unevenness and whether the staining density and color tone are as specified. The dyeing is finished, and the dyed plastic lens is completed.

Examples and comparative examples based on the embodiment will be described below.
(Example 1)
A plastic lens (hereinafter referred to as a lens) was produced and dyed with a predetermined staining solution. Three types of lenses, lenses A, B, and C, were produced.
First, the three types of lenses produced will be described.

[Lens A]
(1.1) Preparation of raw material monomer In a glass container equipped with a stirrer, 50.6 parts by mass of m-xylylene diisocyanate, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9- Trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithia 49.4 parts by mass of a compound obtained by mixing at least one of undecane, or two to three selected from these, 1.2 parts by mass of an ultraviolet absorber (SEESORB701, manufactured by Dipro Kasei Kogyo), and After 0.1 part by mass of an internal mold release agent (Zelec UN, manufactured by Stepan) was added, it was sufficiently stirred and mixed to uniformly disperse or dissolve. Thereafter, 0.005 part by mass of dibutyltin dichloride and 0.005 part by mass of N, N-dimethylcyclohexylamine were further added to this mixed solution, and the mixture was sufficiently stirred and dissolved while maintaining at 30 ° C. Then, the pressure was reduced to 5 mmHg, and deaeration was performed for 30 minutes while continuing stirring to obtain a mixed solution (monomer).

(2.1) Cast polymerization In a lens mold formed by holding two opposing glass molds with a sealing tape, the liquid mixture obtained in the above "(1.1) Preparation of raw material monomers" Injected. And after throwing the lens mold in which the liquid mixture was inject | poured into a warm air heating furnace, it heated up from 30 degreeC to 120 degreeC over 12 hours, and hold | maintained at 120 degreeC for 0.5 hour. And it was allowed to cool to 70 ° C. over 2 hours. Thereafter, the polymerized polymer was released from the lens mold to obtain a thiourethane lens A. The obtained lens A had a refractive index (ne) of 1.67.

[Lens B]
(1.2) Preparation of raw material monomer In a glass container equipped with a stirrer, a polythiol composition containing 50.6 parts by mass of norbornene diisocyanate and pentaerythritol tetrakis (3-mercaptopropionate) as main components is used. 9 parts by mass, 25.5 parts by mass of a polythiol composition based on 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, and 3.0% of an ultraviolet absorber (SEESORB 709, Dipro Kasei Kogyo) After adding 0.1 part by mass of the mass part and the internal mold release agent (Zelec UN, Stepan), the mixture was sufficiently stirred and mixed to uniformly disperse or dissolve. Thereafter, 0.025 parts by mass of dibutyltin dichloride was further added to this mixed solution, and the mixture was sufficiently stirred and dissolved while maintaining at 30 ° C. Then, the pressure was reduced to 5 mmHg, and deaeration was performed for 30 minutes while continuing stirring to obtain a mixed solution (monomer).

(2.2) Casting polymerization In a lens mold formed by holding two opposing glass molds with a sealing tape, the liquid mixture obtained in the above "(1.2) Preparation of raw material monomer" Injected. Then, the lens mold was put into a warm air heating furnace, heated from 30 ° C. to 130 ° C. over 12 hours, held at 130 ° C. for 2 hours, and then allowed to cool to 70 ° C. over 1 hour. Then, the polymer was released from the lens mold to obtain a thiourethane lens B. The obtained lens B had a refractive index (ne) of 1.60.

[Lens C]
(1.3) Preparation of raw material monomer In a glass container equipped with a stirrer, polythiol containing 44.4 parts by mass of m-xylylene diisocyanate and 1,1,3,3-tetrakis (mercaptomethylthio) propane as main components. After 55.6 parts by mass of the composition, 1.2 parts by mass of the ultraviolet absorber (SEESORB701, manufactured by Dipro Kasei Kogyo), and 0.1 parts by mass of the internal mold release agent (Zelec UN, manufactured by Stepan), It was sufficiently stirred and mixed to uniformly disperse or dissolve. Thereafter, 0.02 part by mass of dibutyltin dichloride was further added to this mixed solution, and the mixture was sufficiently stirred and dissolved while maintaining at 30 ° C., then degassed for 30 minutes while continuing to stir while reducing the pressure to 5 mmHg. A mixed liquid (monomer) was obtained.

(2.3) Casting polymerization In a lens mold formed by holding two opposing glass molds with a sealing tape, the mixed solution obtained in the above "(1.3) Preparation of raw material monomer" Injected. Then, the lens mold was put into a warm air heating furnace, heated from 30 ° C. to 120 ° C. over 12 hours, held at 120 ° C. for 0.5 hours, and then allowed to cool to 70 ° C. over 2 hours. . Then, the polymer was released from the lens mold to obtain a thiourethane lens C. The obtained lens C had a refractive index (ne) of 1.70.

  Next, the three types of lenses A, B, and C produced were dyed using a predetermined dyeing solution. For dyeing, after a dyeing solution is prepared, each lens is immersed in the dyeing solution to be colored and dyeing is performed.

(3) Preparation of staining solution While stirring 1 liter of pure water in a beaker with a stirrer, the temperature was kept at 90 ° C. using an indirect tank. Then, 2.5 g of p-phenylphenol (die carrier DK-CN, manufactured by Daiwa Chemical Industry Co., Ltd.) as a dyeing carrier and 2-ethylhexyl sulfate sodium salt (Shintrex (registered) as a surfactant in pure water in a beaker that has been kept warm. (Trademark) EH-R, manufactured by NOF Corporation) was added. As a disperse dye, 2.35 g of a blue dye (FSP Blue AUL-S, manufactured by Futaba Sangyo), 0.14 g of a red dye (FSP Red E-A, manufactured by Futaba Sangyo), a yellow dye (FSP Yellow FL, manufactured by Futaba Sangyo) 0.24 g of brown dye (FSP Red SN, manufactured by Futaba Sangyo) was added. And the aqueous solution in a beaker was stirred for 20 minutes or more using the stirrer, and each additive was disperse | distributed and dissolved uniformly, and the dyeing | staining liquid was created. During preparation of the staining solution, the temperature of the solution was kept constant so as to always maintain a constant temperature of 90 ° C.

(4) Lens staining The prepared dyeing solution was allowed to stand for 30 minutes with stirring while maintaining the liquid temperature at 90 ° C. Then, the lenses A, B, and C obtained by cast polymerization of the raw material monomers were immersed in a dyeing solution for 30 minutes to dye each lens. Then, the colored lenses A, B, and C were pulled up from the dyeing solution and then immersed in water at room temperature for 1 minute to perform water washing to obtain a dyed lens. The stained lens A, lens B, and lens C are referred to as Sample 1, Sample 2, and Sample 3, respectively.

(Example 2)
Example 1 except that 6 ml of cinnamon alcohol was added instead of p-phenylphenol (die carrier DK-CN, manufactured by Daiwa Chemical Industries) as a dyeing carrier in “(3) Preparation of dyeing solution” in Example 1 The dyeing solution was prepared in the same manner as described above, and the three types of lenses A, B, and C produced were similarly dyed. The stained lens A, lens B, and lens C are referred to as sample 4, sample 5, and sample 6, respectively.

(Comparative example)
Comparison of four samples (sample 7 to sample 10) stained with a staining liquid prepared by combining a staining carrier used in Example 1 and Example 2 with a surfactant generally used in the past. As an example. All four samples were stained using only the lens A.

  Sample 7: Example 1 except that 5 ml of polyoxyethylene alkyl ether sodium sulfate (NIKKOL (registered trademark) NES-203, manufactured by Nikko Chemicals) was added instead of 2-ethylhexyl sulfate sodium salt as a surfactant. The dyeing solution was prepared in the same manner, and the lens was dyed in the same manner.

  Sample 8: Example 1 except that 30 ml of polyoxyethylene alkyl ether sodium sulfate (NIKKOL (registered trademark) NES-203, manufactured by Nikko Chemicals) was added in place of 2-ethylhexyl sulfate sodium salt as a surfactant. The dyeing solution was prepared in the same manner, and the lens was dyed in the same manner.

  Sample 9: 6 ml of cinnamon alcohol was added instead of p-phenylphenol as a staining carrier, and sodium polyoxyethylene alkyl ether sulfate (NIKKOL (registered trademark) NES-) was used instead of 2-ethylhexyl sulfate sodium salt as a surfactant. 203, manufactured by Nikko Chemicals), except that 5 ml was added, a staining solution was prepared in the same manner as in Example 1, and the lens was dyed in the same manner.

  Sample 10: A staining solution was prepared in the same manner as in Example 1 except that no staining carrier was added, and the lens was stained in the same manner.

  For each lens of Sample 1 to Sample 10 obtained in Example 1, Example 2, and Comparative Example, the amount of surface deposits adhered to the lens surface was visually evaluated. Thereafter, the lens surface was wiped with a paper soaked with acetone to remove adhered matters including dirt, and the appearance of the lens such as uneven staining was visually evaluated.

The amount of surface deposits and the evaluation criteria for lens appearance are shown below.
(1) Amount of surface deposits ○: No deposits or very little.
Δ: Medium deposits.
X: There are many deposits.
(2) Lens appearance ○: Good appearance.
X: Appearance defects such as color unevenness.

  The evaluation results are shown in Table 1 including a list of dyeing carriers added to the dyeing solution, surfactants, and lenses used for dyeing. In addition, the dyeing | staining carrier and surfactant in Table 1 are represented by the abbreviation of a brand name.

In Table 1, Example 1 (Sample 1 to Sample 3) and Example 2 (Sample 4) using 2-ethylhexyl sulfate sodium salt (Syntrex (registered trademark) EH-R, manufactured by NOF Corporation) as a surfactant. -The lens of Sample 6) has a lens appearance that is free from adhesion of substances on the lens surface and free from color unevenness, regardless of whether phenols or aromatic alcohols are used as the dyeing carrier. It has been. That is, good dyeing can be performed with any lens (lens A, B, C) made of any thiourethane resin having a refractive index of 1.60 or more.
FIG. 1 shows an image of the lens surface in Sample 1 (a lens dyed with the surfactant according to this embodiment).

  On the other hand, in Comparative Example, Sample 7 to Sample 9 using sodium polyoxyethylene alkyl ether sulfate (NIKKOL (registered trademark) NES-203, manufactured by Nikko Chemicals), which is conventionally used as a surfactant, are dyed. Even when phenols or aromatic alcohols are used as the carrier, the amount of deposits on the lens surface is large. Moreover, although 2-ethylhexyl sulfate sodium salt was used as the surfactant, the sample 10 to which no dye carrier was added did not contain the dye carrier, although the adhering substance did not adhere to the lens surface. Therefore, the dyeing speed was extremely slow and almost no dyeing was possible.

  FIG. 2 shows an image of the lens surface in Sample 7 (lens dyed with a conventional surfactant). In FIG. 2, the deposit is locally generated on the lens surface, and the portion imaged black in the region a indicated by the two-dot chain line ellipse indicates the deposit.

  Samples 1 to 6 (Example 1 and Example 2) were able to remove the deposits by wiping once with a paper containing acetone even if the deposits were slightly adhered. However, in the samples 7 to 9 shown in the comparative example, the adhering matter firmly adhered to the lens surface, and it was necessary to wipe it with a paper containing acetone four times or more.

Next, based on the above evaluation results, the preferred amount of 2-ethylhexyl sulfate sodium salt (surfactant) added in the staining solution was confirmed.
As a dyeing carrier, 2.5 g of phenolic p-phenylphenol (die carrier DK-CN, manufactured by Daiwa Chemical Industry) used in Examples 1 and 2 above and 6 ml of aromatic alcohol cinnamon alcohol were added. To each staining solution, 0.5 ml, 1 ml, 30 ml, and 35 ml of 2-ethylhexyl sulfate sodium salt (Syntrex (registered trademark) EH-R, manufactured by NOF Corporation) was added as a surfactant, for a total of 8 types The dyeing solution was prepared. And lens A was dye | stained using each dyeing | staining liquid.

  Samples 11 to 11 were obtained by staining lenses stained with staining solutions using p-phenylphenol as a staining carrier and adding 0.5 ml, 1 ml, 30 ml, and 35 ml of a surfactant (2-ethylhexyl sulfate sodium salt), respectively, in this order. 14 is called. Similarly, lenses stained with a staining solution using cinnamon alcohol as a staining carrier are referred to as Sample 15 to Sample 18 in this order.

And each lens of the obtained samples 11 to 18 was evaluated based on the evaluation items (amount of surface deposits, lens appearance) and evaluation criteria.
The evaluation results are shown in Table 2 including the addition amount of the dyeing carrier and the surfactant. In addition, the dyeing | staining carrier and surfactant in Table 2 are represented by the abbreviation of a brand name.

In Table 2, addition of surfactant Syntrex (registered trademark) (2-ethylhexyl sulfate sodium salt), regardless of whether the dyeing carrier contained in the dyeing solution is phenols or aromatic alcohols Samples 11 and 15 having an amount of 0.5 ml are found to adhere to the lens surface. On the other hand, in Sample 14 and Sample 18 in which the added amount of Syntrex (registered trademark) was 35 ml, turbidity occurred in the staining solution during staining. Color unevenness occurred in the entire dyed lens.
Other samples 12 and 16 with an addition amount of SYNTREX (registered trademark) of 1 ml, and samples 13 and 17 with an addition amount of 30 ml have no adhesion on the lens surface, and color unevenness etc. No lens appearance was obtained.

Therefore, from the confirmation of the addition amount of the surfactant and the evaluation results of Examples 1 and 2, the dyeing solution for dyeing the plastic lens made of thiourethane-based resin is 2 in the range of 1 to 30 ml per liter of water. -It is preferable to add ethylhexyl sulfate sodium salt (surfactant).
In addition, although the confirmation of the addition amount of Syntrex (registered trademark) has been described for the case where the lens A (refractive index 1.67) is used as the lens to be dyed, the lens B (refractive index 1.60) and the lens C ( The same was true for the case of refractive index 1.70).

  The plastic lens staining method described above can be suitably used for plastic lenses such as spectacle lenses, camera lenses, telescope lenses, microscope lenses, and stepper condenser lenses. Furthermore, the technical idea of this embodiment can also be applied to dyeing various plastic substrates such as plastic sheets and films.

According to such a plastic lens dyeing method, the following effects can be obtained.
(1) The dyeing solution for dyeing the plastic lens is a 2-ethylhexyl sulfate sodium salt represented by the above general formula (1), which contains a disperse dye, a dyeing carrier, and a surfactant. Thus, the dispersibility of the disperse dye in the dyeing liquid is improved, and the disperse dye or the mixture of the disperse dye and the dye carrier can be prevented from adhering to the lens surface. As a result, the amount of organic solvent such as acetone used for wiping can be reduced. In addition, the dyeing speed of the plastic lens can be sufficiently ensured by not reducing the affinity between the disperse dye and the plastic lens. Therefore, it is possible to obtain a dyeing method capable of exhibiting sufficient dyeability and dyeing stability, and to avoid operations such as dropping the deposits.

  (2) The dispersibility of the disperse dye in the dyeing solution is improved because the content of 2-ethylhexyl sulfate sodium salt (surfactant) contained in the dyeing solution is in the range of 1 ml to 30 ml per liter of water. In addition, the disperse dye or the mixture of the disperse dye and the dyeing carrier can be prevented from adhering to the lens surface. Furthermore, a thiourethane plastic lens having a refractive index of 1.60 or more can be easily dyed. That is, a high refractive index plastic lens can be easily dyed.

The image of the lens surface dye | stained using the surfactant which concerns on this embodiment. An image of a lens surface dyed with a conventional surfactant.

Explanation of symbols

  a: A region where a deposit adheres to the lens surface.

Claims (5)

A method for dyeing a plastic lens, wherein the plastic lens is colored by immersing the plastic lens in a staining solution,
The dyeing liquid contains a disperse dye, a dyeing carrier, and a surfactant,
The method for dyeing a plastic lens, wherein the surfactant is 2-ethylhexyl sulfate sodium salt represented by the following general formula (1).
In the dyeing method of the plastic lens according to claim 1,
The method for dyeing plastic lenses, wherein the content of 2-ethylhexyl sulfate sodium salt is in the range of 1 ml to 30 ml per liter of water. The plastic lens dyeing method according to claim 1 or 2,
A plastic lens dyeing method, wherein the plastic lens is a thiourethane plastic lens. In the dyeing | staining method of the plastic lens as described in any one of Claims 1-3,
The plastic lens dyeing method, wherein the dyeing carrier is at least one compound selected from phenols or alcohols having an aromatic ring. In the plastic lens dyeing method according to claim 4,
The phenols or alcohols having an aromatic ring are
A method for dyeing a plastic lens, which is p-phenylphenol, m-phenylphenol, o-phenylphenol, cinnamon alcohol, or benzyl alcohol.