JPH09269401A - Plastic lens having absorptivity for uv ray and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unevenness in absorptivity for UV rays on the lens surface by dissolving a compd. having absorptivity for UV rays in an org. solvent and applying the obtd. soln on a plastic base body. SOLUTION: A compd. having absorptivity for UV rays is dissolved in an org. solvent and applied on a plastic base body. The compd. having absorptivity for UV rays has an absorption region in the range of 1300 to 800cm<-1> , 1900 to 1500cm<-1> or 3800 to 2700cm<-1> . The plastic lens has <1% average transmittance for rays in the wavelength range of 300 to 400nm. The org. solvent used has >=70 deg.C boiling point. This is because heating the plastic lens to >=60 deg.C is required to impregnate the base body with the UV absorbent and that a solvent having higher boiling point than the heating temp. is required. As for the solvent, methanol, ethanol, etc., can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for imparting an ultraviolet absorbing ability to a plastic lens, a method for producing a plastic lens having the ultraviolet absorbing ability, and the plastic lens.

[0002]

2. Description of the Related Art Ultraviolet rays have a wavelength of about 200 to 400 mμ.
It is said that it is a ray of light and has a bad effect on the human body.
It is also known that the eyes of the human body are particularly vulnerable to the effects of ultraviolet rays, and that cataracts are likely to occur if the eyes are exposed to excessive ultraviolet rays for a long period of time. It is also known that absorption of light with a wavelength of 400 nm or less can prevent glare, make objects easier to see, and make eyes less tired.

[0003] For the purpose of preventing the harmful effects of these ultraviolet rays on the human body, the ability to absorb ultraviolet rays in cosmetics, clothes, and umbrellas (to prevent ultraviolet rays from reaching the human body by absorbing ultraviolet rays in fibers or dyes) Those with the mark are sold. Also in the field of spectacle lenses, a plastic lens having a UV absorbing ability (a lens that absorbs an ultraviolet ray by the lens and does not reach the eye) is claimed, and its demand has recently been increasing.

Conventionally, the following methods have been used as a method for imparting an ultraviolet absorbing ability to a plastic lens. The first method is a method of kneading a substance called an ultraviolet absorber into a monomer (liquid) that becomes a plastic lens substrate (adding and mixing an ultraviolet absorber to a liquid monomer) in a plastic lens substrate molding process. is there. After the ultraviolet absorber is kneaded, the monomer is poured into a molding die and cured by heating or the like to mold a plastic lens. The second method is a method of dispersing an ultraviolet absorber in water to form an aqueous solution, and immersing the molded lens substrate in the aqueous solution to impregnate the surface of the lens substrate with the ultraviolet absorber. The third method is a method of depositing an inorganic substance that absorbs ultraviolet rays on the surface of the lens substrate by vacuum deposition.

For example, Japanese Patent Application Laid-Open No. 60-221704 proposes an optical element that transmits light having a wavelength within a specific range among light rays in the visible region and absorbs other ultraviolet rays. The ultraviolet absorber described here is a colorant composed of a blue dye such as disposer blue or disposer orange or an orange dye, and is a method of impregnating the surface of a lens with the colorant.

[0006]

Recently, due to ozone layer depletion, which is one of the environmental problems, ultraviolet rays in the sun's rays are not blocked by the ozone layer, and more ultraviolet rays than before are directly transmitted to the ground. The phenomenon of reaching is happening. As described above, since the eye is a part that is easily affected by ultraviolet rays, the demand for eyeglass lenses that absorb ultraviolet rays is increasing.

Conventionally, in order to manufacture a plastic lens having the light resistance of a plastic lens (durability against yellowing of a plastic material due to irradiation of sunlight, deterioration such as cracks), weather resistance and ultraviolet absorption ability, as described above. At the time of lens molding, a method of adding an ultraviolet absorber was used, and the addition amount of the ultraviolet absorber was changed and added to the monomer.

However, in order to impart the ultraviolet absorbing ability,
When a very small amount of the ultraviolet absorber is added to the monomer, the monomer cannot be cured and the lens cannot be molded. This was particularly remarkable when added to diethylene glycol bisallyl carbonate resin. In addition, an ultraviolet absorber was added to other synthetic resins, and molding of lenses was tried. However, although molding was possible, there was a problem in that the lens had a bad appearance and was colored in yellow, resulting in a very unsightly lens.

From these problems, it has been found that it is very difficult to give the plastic lens an ultraviolet absorbing ability for absorbing light having a wavelength of 400 nm or less by the kneading method. The present inventors decided to use the dipping method, which is one of the conventional manufacturing methods described above. Then, the present inventors attempted to impregnate the surface of the lens substrate with the ultraviolet absorber by a method of dispersing the ultraviolet absorber in water and impregnating the surface of the plastic lens substrate. However, even with this method, it was not possible to sufficiently absorb light having a wavelength of 400 nm or less.

Further, a method of coating an inorganic substance such as Ti, which is a material having an ultraviolet absorbing ability, by a vacuum deposition method was tried. However, there is no good inorganic substance capable of absorbing light having a wavelength of 400 nm or less, and there is a limit to the method using the vacuum deposition method. And, JP-A-60-22170
The optical element manufactured by the method of Japanese Patent Publication No. 4 must use a colorant having a limited color, so that it is not possible to freely select a color or manufacture a lens having high transmittance. is there.

According to the method disclosed in Japanese Patent Application Laid-Open No. 1-200033, when applied to a lens substrate, unevenness occurs on the lens surface, and uniform ultraviolet absorbing ability cannot be imparted. Further, if it is desired to obtain a desired ultraviolet ray absorbing ability, a very long dipping time is required, resulting in a very poor productivity. Alternatively, no matter how long the immersion time is, the equilibrium state is reached before the desired ultraviolet absorbing ability is reached, so that the desired ultraviolet absorbing ability cannot be obtained.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above conventional problems and obtain a plastic lens that absorbs light having a wavelength of 400 nm or less.

[0013]

Among the conventional techniques, the dipping method is the most efficient method, and since the plastic lens having the ultraviolet absorbing ability can be manufactured at a low cost, the present inventors have improved the dipping method. Therefore, the problem that the ultraviolet absorbing ability cannot be uniformly given to the lens surface was examined.

As a result, it was found that the reason why the ultraviolet absorbing ability cannot be imparted uniformly to the lens surface is that the ultraviolet absorbing agent is partially aggregated on the lens surface. Further, the inventors furthered the study and studied to prevent the ultraviolet absorber from partially aggregating on the lens surface.
Therefore, in order to solve each of the above problems, it was decided to use water as a solvent, make a solution in which an ultraviolet absorber was dissolved, and immerse the lens substrate. Then, an attempt was made to increase the concentration of the ultraviolet absorber in the solution, but again it was not possible to uniformly impart the ultraviolet absorbing ability to the lens surface. From these results, the present inventors have found that the ultraviolet absorber aggregates due to the problem of solubility between the ultraviolet absorber and water that is a medium for impregnating the lens with the ultraviolet absorber, and the ultraviolet absorber is evenly distributed on the lens substrate surface. It has been found that it is not possible to impregnate UV absorbers.

When the present inventors studied the cause of this,
Increasing the concentration of the UV absorber in the water of the solvent causes the UV absorber to aggregate in the solution, preventing the UV absorber from entering the surface of the plastic substrate, and imparting a uniform UV absorbing ability to the lens surface. It turns out that I can't. Therefore, the present inventor has decided to solve the problem relating to the aggregation of the ultraviolet absorbent by using a solvent other than water and uniformly dissolving the ultraviolet absorbent in the solvent, thus completing the present invention.

Therefore, the first aspect of the present invention is "a method for producing a plastic lens having an ultraviolet absorbing ability, which is characterized in that a compound having an ultraviolet absorbing ability is dissolved in an organic solvent and applied to a plastic lens substrate. Claim 1) "is provided. Secondly, "the compound having the ultraviolet absorbing ability is 1300 to 800 cm ^-1 or 1900 to ¹
500 cm ^-1 or manufacturing method according to claim 1, characterized by having an absorption region 3800~2700cm ^-1 (claim 2) "provides. Thirdly, "300 nm-40
A plastic lens (claim 3) having an ultraviolet absorbing ability according to claim 1 having an average light transmittance of less than 1% for light with a wavelength of 0 nm.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION As the ultraviolet absorber used in the present invention, for example, a benzophenone compound (1), a salicylate compound (2), or a benzotriazole compound (2) having the following chemical formula can be used. However, the present invention is not limited to this, and it is possible to use a conventional substance having an ultraviolet absorbing ability.

These substances are one or more kinds of surfactants, a benzophenone compound represented by the following general formula (1), a salicylate compound represented by the general formula (2) and a general formula (3). At least one compound selected from benzotriazole compounds and a boiling point of 75 ° C.
A method for producing an ultraviolet absorbing plastic lens, which comprises imparting ultraviolet absorbing ability by immersing a plastic lens substrate in an aqueous solution containing at least one organic solvent as described above. (In the formula, R _{1 to} R ₄ are each independently an OH group, a C _{1 to} C ₁₀ alkoxy group, a C _{1 to} C ₅
Represents an alkyl group, a halogen atom or a hydrogen atom, and at least one of R _{1 to} R ₂ is an OH group. )

[0019]

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[0020]

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[0021]

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The ultraviolet absorbing material used in the present invention is 1300 to 800 cm ^-1 or 190 in the infrared region.
0-1500 cm ^-1 or 3800-2700 cm ^-1
It has an absorption region. In the present invention, when the plastic lens substrate is impregnated with an ultraviolet absorber,
A solvent having a high solubility of the ultraviolet absorber is used in order to impart a high ultraviolet absorbing ability. When using the dipping method,
It is necessary to heat the plastic lens substrate surface to about 60 ° C. or more in order to impregnate the surface with the ultraviolet absorber. Therefore, the solvent used in the present invention must have a boiling point of about 60 degrees or higher. It is preferably 70 degrees or more. 60
This is because if the solvent has a boiling point lower than the above, the solvent will boil when heated and cannot be used. It is also a necessary condition that there is no danger or toxicity.

Under these conditions, the solvent used in the present invention is methanol, ethanol, butanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol. , 2-pentanol, 3-
Pentanol and 2-methyl-1-butanol can be used, and these can be used alone or as a mixture of two or more kinds. Further, it is also possible to use water and the above solvent in a mixture. The boiling point of the solvent is preferably 70 ° C or higher. The reason is that in the present invention, in order to impregnate the plastic lens substrate with the ultraviolet absorber, the temperature is 60 ° C.
The above heating is necessary, but only a solvent having a boiling point higher than that can be used.

The amount of the ultraviolet absorber dissolved in the solvent is
Less than 500 ml in 1 liter of aqueous solution. If necessary, a surfactant, various dispersants, antioxidants, stabilizers, accelerators, and other additives can be added. The temperature of the impregnating liquid when the surface of the plastic lens substrate is impregnated with the ultraviolet absorber is 30 ° C to 100 ° C, preferably 50 ° C.
It is in the range of ℃ to 95 ℃. The processing time is 1 second to 1 hour, preferably 30 seconds to 30 minutes. These conditions are determined by the material of the ultraviolet absorber and the base material, taking into consideration the occurrence of aggregation of the ultraviolet absorber and the influence on the base material.

Further, after this treatment, a primer layer for freely dyeing and, if necessary, improving impact resistance and adhesion, a hard coat layer for improving scratch resistance, an antireflection film, and It is also possible to apply other films. As the material of the primer layer, a material such as a urethane compound is used. The hard coat layer can be formed by a wet method such as a dipping method, a spin coating method, a spray method, or a dry method such as a vacuum evaporation method, a CVD method, or a sputtering method. An organic silicon compound or the like is used as the material. It is possible. In addition, fine particles such as titanium oxide, antimony oxide, tin oxide, tungsten oxide, aluminum oxide, iron oxide, tantalum oxide, and silicon oxide are added to the hard coat layer to prevent the occurrence of interference fringes, prevent static electricity, and improve hardness. It is possible to add effects such as.

The material of the plastic lens substrate used in the present invention is, for example, polymethylmethacrylate and its copolymer, acrylonitrile-styrene copolymer, polycarbonate, cellulose acetate, polyvinyl chloride, polyethylene terephthalate, epoxy resin, Unsaturated polyester resin, polyurethane resin, CR-39 polymer, or monomer mixture containing one or more polyisocyanates and one or more polyols and / or one or more polythiols Can be used for the material obtained by polymerizing.

It is also possible to improve productivity by adding a surfactant.

[0028]

Example 1 (1) Manufacture of Plastic Lens Base Material A lens molding die comprising two lens molding dies and a gasket is prepared. 100 parts of diethylene glycol bisallyl carbonate (monomer resin), which is a raw material for the lens matrix, and 3 parts of diisopropyl peroxydicarbonate as a polymerization initiator are injected into the mold. This was mounted in an electric furnace, and the temperature was raised from about 40 to 80 degrees with a heating time of 20 hours to carry out polymerization to cure the monomer resin. (2) Preparation of UV Absorber and Impregnation into Plastic Substrate As a UV absorber, 100 g of benzophenone compound 2,2′-dihydroxy-4,4′-dimethoxy-benzophenone and 30 ml of benzyl alcohol as an organic solvent are used. , And mix it with pure water to make 1 liter,
An ultraviolet absorbent impregnating solution was prepared. This was heated to 93 ° C. The diethylene glycol bisallyl carbonate resin lens molded in (1) was immersed in the ultraviolet absorbent impregnating liquid for 20 minutes. The lens after the immersion was dried by leaving it at room temperature or by forced drying, for example, leaving it in a constant temperature layer.

The lens thus obtained was analyzed for transmittance in the wavelength range of 380 to 420 nm with a spectrophotometer U-3410 manufactured by Hitachi, Ltd. The result is shown in FIG.
From these results, the lens of the present invention has a transmittance of 2.5% for light having a wavelength of 400 nm, and thus a lens capable of absorbing ultraviolet rays could be manufactured. Furthermore, as a result of performing 100 similar treatments with the same impregnation liquid, an average of 2,75%
A lens having a transmittance of 1 was obtained.

[0030]

Example 2 (1) Production of plastic lens substrate 11 parts of hexamethylene diisocyanate, 44 parts of 2-hydroxyethyl methacrylate, 20 parts of 2,4,6-tribromophenyl methacrylate, 15 parts of methylstyrene
Parts, 10 parts of divinylbenzene, and 0.01 parts of dibutyltin dilaurate were allowed to react, and a mixture of a liquid urethane monomer and 2 parts of uraloyl peroxide as a polymerization initiator was poured into a molding die in the same manner as in Example 1, Polymerization was carried out by raising the temperature from 50 to 110 ° C. over 20 hours.
After the polymerization was completed, the molded lens substrate was taken out of the molding die, placed in a heating furnace, and heat-treated at 120 ° C. for 1 hour. (2) Adjustment of UV Absorber and Impregnation into Plastic Base Material 120 g of ethyl-2-cyano-3,3-diphenylacrylate as a UV absorber, 200 ml of isobutyl alcohol as an organic solvent and pure water were added to make 1 l,
The ultraviolet absorbent impregnated liquid was adjusted and heated to 90 ° C.
The lens substrate molded in (1) was immersed in this impregnating liquid for 15 minutes.

As a result of measuring the transmittance of this lens in the same manner as in Example 1, it was possible to manufacture a lens capable of absorbing 4.8% of ultraviolet light having a wavelength of 400 nm. Also, 1
By adjusting the ultraviolet absorbent impregnating solution once, it was possible to process 100 lens substrates. Furthermore, a dyed lens can be produced by mixing a commercially available disperse dye in the impregnation liquid.

[Comparative Example] Diethylene glycol bisallyl carbonate resin lens was used as a lens substrate, and dissolved in 10 g pure 1 l of 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone, which is an ultraviolet absorber, and impregnated with the ultraviolet absorber. The liquid was adjusted and heated to 93 ° C. It was immersed in this ultraviolet absorbent impregnating liquid for 60 minutes.

This lens is shown in FIG. 1 like 40
It was difficult to absorb light with a wavelength of 0 nm or less.

[0034]

According to the present invention, it is possible to manufacture a lens that absorbs light of a specific wavelength and has a large amount and uniform properties by adjusting the impregnating liquid once. Since the lens of the present invention has a uniform ultraviolet absorbing ability over the entire surface, a lens with less eye fatigue can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing spectral transmittance curves of plastic lenses impregnated with an ultraviolet absorber prepared in Examples and Comparative Examples.

[Explanation of symbols]

1 ... Spectral distribution curve of a plastic lens impregnated with an ultraviolet absorber produced in the example 2 ... Spectral distribution curve of a plastic lens impregnated with an ultraviolet absorber produced in a comparative example

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Claims (4)

[Claims] 1. A method for producing a plastic lens having an ultraviolet absorbing ability, which comprises dissolving a compound having an ultraviolet absorbing ability in an organic solvent and applying this to a plastic lens substrate. 2. The compound having the ultraviolet absorbing ability is 13
The manufacturing method according to claim 1, which has an absorption region at 00 to 800 cm ^-1 or 1900 to 1500 cm ^-1 or 3800 to 2700 cm ^-1 . 3. The method according to claim 1, wherein the boiling point of the organic solvent is 70 ° C. or higher. 4. A plastic lens having an ultraviolet absorbing ability according to claim 1, which has an average light transmittance of less than 1% for light having a wavelength of 300 nm to 400 nm.