JPH10282301A - Plastic lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict the occurrence of interference fringes by making the refraction factors of a base material, intermediate layers and a hard coat layer gradually smaller from the base material side toward the hard coat layer side. SOLUTION: If intermediate layers 2-5 are formed in a multilayered structure between a plastic lens base material 6 and a hard coat layer 1, a difference in refraction factor between the layers neighboring each other is set to be smaller than about 0.1 and the refraction factors are made gradually smaller from the plastic lens base material 6 toward the hard coat layer 1. In this way, even if the refraction factor of the plastic lens base material 6 is different 0.2 or more from that of the hard coat layer 1, a lens with restricted interference fringes can be manufactured. Similarly, if a single intermediate layer is formed, it is preferable that differences in refraction factor between the base material and the intermediate layer and between the hard coat layer and the intermediate layer are smaller than 0.1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens in which the occurrence of interference fringes is suppressed.

[0002]

2. Description of the Related Art Recently, plastic lenses have been widely used as optical materials because of their advantages such as light weight, excellent impact resistance, easy workability, and easy dyeing. Widespread. However, plastic lenses generally have the disadvantage that they are easily damaged. Therefore, usually, a scratch resistance is improved by forming a hard coat layer on the surface of a plastic lens substrate.

[0003] As a material for forming the hard coat layer,
It is common to use an organosilicon compound. For example, when manufacturing a lens using a relatively low refractive index plastic lens substrate having a refractive index of about 1.5, a hard coat layer is usually formed using an organosilicon compound. The refractive index of the hard coat layer is generally about 1.5, which is almost the same as that of the plastic lens substrate.

Further, in recent years, a large number of high refractive index plastic lens substrates having a refractive index of about 1.65 or more have been developed.
Even when a lens is manufactured using these high-refractive index plastic lens substrates, it was possible to improve the scratch resistance of the lens by forming a hard coat layer made of an organosilicon compound. Was generated and a problem occurred in appearance. This interference fringe is caused by a large difference in the refractive index between the substrate and the hard coat layer. Conventionally, in order to solve the problem of the interference fringes, it has been performed to reduce the difference in the refractive index between the hard coat layer and the plastic lens substrate. It is difficult to adjust the refractive index of the lens substrate, and the work efficiency is poor. Therefore, the refractive index of the hard coat layer is increased to approach the refractive index of the plastic lens substrate, and the refractive index difference between the two is reduced. That has been done.

A method for increasing the refractive index of the hard coat layer is as follows.
Many have been reported so far. As a general method, there is a method of adjusting the refractive index by adding inorganic oxide fine particles to an organosilicon compound to be a hard coat layer. Japanese Patent Publication No. Sho 61-54331 discloses a coating technique in which an antimony pentoxide sol and an organic compound containing an organosilicon compound are used as a material on a substrate, and a film is formed from the organic compound. JP-A-5-287241 discloses a hard coat layer containing, in addition to antimony oxide sol, fine particles selected from titania, cerium oxide, tin oxide, tungsten oxide, iron oxide and the like in an organosilicon compound. ing.

[0006]

However, in the conventional method of suppressing the occurrence of interference fringes by making the refractive indices of the plastic lens substrate and the hard coat layer substantially the same, the refractive index of the plastic lens substrate is reduced. , The refractive index of the hard coat layer had to be adjusted each time. Therefore, problems such as an increase in production cost and a decrease in production efficiency may occur.

Further, oxide fine particles added to the hard coat layer for adjusting the refractive index are expensive,
In the case of forming a hard coat layer having a large difference in refractive index from the base material, a large amount of the hard coat layer has to be added, so that there is a problem that a burden is increased in terms of manufacturing cost.

[0008]

A case where the refractive index of a plastic lens substrate is different from that of a hard coat layer directly formed thereon is considered. When a film is formed on a substrate, interference fringes always occur. This is related to the thickness of the deposited film. If the thickness of the formed film is uniform, there is theoretically no occurrence of interference fringes. However, since the thickness of the actually formed film is not uniform, interference fringes occur. Further, when the difference in the refractive index between the substrate and the film formed thereon is large, the reflectance at the interface between the substrate and the film increases. This makes the interference fringes more noticeable.

In the interference fringes generated due to the nonuniformity of the thickness of the hard coat layer, the light reflected on the upper surface of the hard coat layer interferes with the light reflected on the interface between the hard coat layer and the plastic lens substrate. It is known that this is caused by things. Considering the case where light is perpendicularly incident on a substance having a refractive index of n2 from a substance having a refractive index of n1, a reflectance R at an interface between the two substances is expressed by the following equation 1 as n = n2 / n1.

[0010]

(Equation 1)

Thus, it is clear that the greater the difference between the refractive indices of the two substances constituting the interface, the higher the reflectance at the interface. With these things in mind,
In order to suppress the occurrence of interference fringes, the unevenness of the film thickness of the hard coat layer is eliminated, or the reflectance at the interface between the hard coat layer and the plastic substrate is reduced, and the light that contributes to the formation of interference fringes is reduced. It turns out that it is effective to reduce the ratio.

The present inventors first attempted to make the film thickness uniform when forming a hard coat layer on a lens substrate using an organosilicon compound. However, the surface of the lens substrate is generally a curved surface, and it has been very difficult to precisely make the film thickness of the hard coat layer uniform. Therefore, it was abandoned to suppress the generation of interference fringes by forming the hard coat layer with a uniform thickness.

Next, the difference in the refractive index between the materials forming the hard coat layer and the plastic lens substrate is reduced to suppress the occurrence of interference fringes. As a result of repeated research, rather than adjusting the refractive index of the hard coat layer to reduce the refractive index difference, the refractive index between the base material and the hard coat layer is between the base material and the hard coat layer. By providing an intermediate layer having a refractive index and reducing the refractive index between the base material and the hard coat layer, without adding oxide fine particles or the like for adjusting the refractive index to the base material and the hard coat layer, It was found that the occurrence of interference fringes was suppressed.

Therefore, the present invention firstly provides a plastic lens having a plastic lens substrate, a single-layered intermediate layer formed on the plastic lens substrate, and a hard coat layer formed on the intermediate layer. Wherein the refractive index of the base material, the refractive index of the intermediate layer, and the refractive index of the hard coat layer decrease from the base material side toward the hard coat layer side. Item 1) ”is provided. Second, "the difference between the refractive indices of the plastic lens substrate and the intermediate layer and the difference between the refractive indices of the intermediate layer and the hard coat layer are each approximately 0.
A plastic lens according to claim 1 (claim 2), which is smaller than 1. Thirdly, there is provided "a plastic lens according to claim 1, wherein the intermediate layer having the single-layer structure has a multilayer structure." Fourth, the difference in the refractive index between the layers in the intermediate layer having the multilayer structure is substantially 0.1, the difference in the refractive index between the plastic lens substrate and the intermediate layer adjacent to the plastic lens substrate, The difference in refractive index between the layer and the intermediate layer adjacent to the hard coat layer is less than about 0.1, and the refractive index gradually decreases from the substrate side toward the hard coat layer. The plastic lens according to claim 3 (claim 4) "is provided. Fifthly, the plastic lens according to any one of claims 1, 2, 3, and 4, wherein the intermediate layer is mainly composed of a polyvinyl acetal resin and / or a polymer thereof (claim 5). .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an intermediate layer having a refractive index substantially intermediate between the refractive indexes of the hard coat layer and the substrate is formed, and the occurrence of interference fringes can be reduced without changing the properties of the hard coat layer. Can be suppressed. According to the study of the present inventors, it is most preferable that the difference between the two refractive indexes is smaller than about 0.1, and when the difference between the two refractive indexes becomes about 0.1 or more, the interference fringes become conspicuous. Is known to come.

FIG. 1 is a schematic side view of a plastic lens according to the present invention. As shown in FIG. 1, when one intermediate layer (2) is provided between the plastic lens substrate (3) and the hard coat layer (1), the refractive index of the intermediate layer (2) is set to If the refractive index is substantially intermediate between the refractive index of (1) and the refractive index of the hard coat layer (1), interference fringes can be reduced. If the refractive index of the intermediate layer is adjusted so that the difference in refractive index between the intermediate layer (2) and the hard coat layer (1) becomes smaller than about 0.1, the interference fringes of the hard coat layer (1) can be further reduced. It is possible to obtain an optical article which is reduced and has practically no problem of interference fringes.

If the difference between the refractive indices of the intermediate layer (2) and the plastic lens substrate (3) is made smaller than about 0.1, the thickness of the intermediate layer (2) becomes nonuniform. The interference fringes that occur can be further reduced. Therefore, in the case of a spectacle lens having the configuration shown in FIG. 1, the difference in the refractive index between the hard coat layer (1) and the plastic lens substrate (3) is allowed to be about 0.2 at the maximum. Therefore, conventionally, a hard coat layer having a refractive index that causes interference fringes can also be formed,
The allowable range of the refractive index of the hard coat layer is expanded.

The difference in the refractive index between the hard coat layer and the substrate is about 0.1.
In the case of two or more, the number of intermediate layers may be plural.
FIG. 2 is a schematic side view of a lens provided with four intermediate layers according to the present invention. As shown in FIG. 2, the intermediate layer (2),
When (3), (4) and (5) have a multilayer structure, the difference between the refractive indices between adjacent layers is set to be smaller than about 0.1 and the plastic lens substrate (6 ) To the hard coat layer (1) so that the refractive index gradually decreases. With such a configuration, it is possible to manufacture a lens in which interference fringes are suppressed even if the refractive index between the plastic lens substrate (6) and the hard coat layer (1) is different by about 0.2 or more. Become. Naturally, it is preferable that the difference in the refractive index between the base material and the intermediate layer and between the hard coat layer and the intermediate layer be smaller than 0.1 as in the case of forming the single-layer intermediate layer.

When a single intermediate layer is provided, its thickness is
It is preferable that the thickness be about 0.05 to 50 μm. When a multilayer intermediate layer is formed, the thickness of each layer is 0.05 μm.
As described above, the total film thickness of the entire layer is preferably 50 μm or less. The reason for setting the minimum film thickness to 0.05 μm is that this film thickness is the smallest film thickness that can be formed by the current film forming technology. The reason for setting the thickness to 50 μm or less is that if the film thickness is further increased, the surface accuracy is deteriorated.

As the material for forming the intermediate layer according to the present invention, for example, cross-linked polyvinyl acetal, acryl-urethane copolymer, epoxy resin-based material, melamine resin-based material and the like can be used. Adjustment of the refractive index is performed by adding a particulate inorganic substance composed of a metal oxide to the above-described organic compound and controlling the amount of addition. Examples of the particulate inorganic oxide dispersed in the intermediate layer include zinc oxide, aluminum oxide, titanium oxide, zirconium oxide, tin oxide, antimony oxide, silicon oxide, beryllium oxide, tungsten oxide, iron oxide, and cerium oxide. Is not limited to these.
These particulate inorganic oxides may be added alone or as a mixture of a plurality of particulates. Alternatively, a plurality of fine particles may be in a composite state.

Generally, the refractive index of the metal oxide is higher than the refractive index of polyvinyl acetal. Therefore, the refractive index of the intermediate layer increases as the amount of the metal oxide fine particles increases. In dispersing the metal oxide fine particles, as a form before the dispersion, a fine powder form can be used, but in order to achieve the object of the present invention, a colloidal form in a liquid volatile dispersion solvent is used. It is particularly effective to mix a dispersion (particulate inorganic substance made of metal oxide) with a vehicle component (substrate) and then evaporate the volatile dispersion medium. At that time, the average particle diameter of the fine-particle inorganic oxide is 1 to 3
About 100 nm is desirable, preferably 1 to 50 nm.
nm. If the average particle size is too large, when dispersed in a vehicle component and then cured on a substrate, scattered light is strongly generated, and the appearance becomes cloudy, which is not desirable. Incidentally, these fine particles may be present in an aggregated state.
In such a case, the aggregated particles should be about 100
Those having a thickness of ~ 200 nm are preferred.

As the volatile dispersion medium, hydrocarbons, halogenated hydrocarbons, alcohols, ketones, esters, ethers and other known solvents can be used. Further, these solvents may be used alone or as a mixture of two or more kinds. That is, the formation of the intermediate layer composed of crosslinked polyvinyl acetal is performed by dissolving or containing at least one of a polyvinyl acetal as a main component, a hydrolyzable organosilane compound or a dialdehyde as a crosslinking agent, and a curing catalyst. The coating can be performed by dip-coating or spin-coating a coating liquid prepared by dispersing a particulate inorganic substance made of a metal oxide on a plastic lens, followed by heat treatment.

As the polyvinyl acetal as the main component of the composition of the intermediate layer, those having 0 to 20 carbon atoms in the alkyl group of the acetal portion can be used, preferably those having 0 to 10 carbon atoms, and particularly preferred are those having 0 to 10 carbon atoms. Polyvinyl butyral having 3 carbon atoms. Acetalization degree of 10 to 90% can be used, preferably 20 to 80%
Use things. The average degree of polymerization of the polyvinyl acetal is preferably not more than 5,000, more preferably 100 to 3,000. If the average degree of polymerization is too high, it will be difficult to dissolve in a solvent and the viscosity of the coating liquid will increase, which is not practical. On the other hand, if the average degree of polymerization is too low, the impact resistance when the intermediate layer is formed on a plastic lens is not sufficiently improved, which is not preferable.

Examples of the crosslinking agent include tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane,
Organosilane compounds such as tetraethoxysilane, ethyltriethoxysilane and diethyldiethoxysilane are used. These organosilane compounds may be used alone or as a mixture of two or more. In these organosilane compounds, a hydrolyzable group is hydrolyzed to generate a silanol group, and cross-linking is performed between molecules or within a molecule by dehydration-condensation with a hydroxyl group in polyvinyl acetal by the action of a catalyst and heat. The addition amount of these organosilane compounds is 0.01 to 30% by weight of the coating solution for the intermediate layer, and more preferably 0.1 to 30% by weight.
20% by weight. Further, these organosilane compounds may be added as they are, or may be added after a hydrolysis reaction has been performed in advance.

Further, organotitanium compounds such as tetramethoxytitanium, methyltrimethoxytitanium, dimethyldimethoxytitanium, tetraethoxytitanium, ethyltriethoxytitanium and diethyldiethoxytitanium can also be used as the crosslinking agent. These organotitanium compounds may be used alone or as a mixture of two or more. Further, these organotitanium compounds undergo cross-linking between molecules or within a molecule by a hydrolysis and dehydration condensation reaction similarly to the above-mentioned organosilane compounds. The addition amount of these organotitanium compounds is 0.01 to 30% by weight, more preferably 0.1 to 20% by weight, of the coating solution for the intermediate layer. Further, these organotitanium compounds may be added as they are, or may be added after a hydrolysis reaction has been performed in advance.

Further, glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde,
A dialdehyde compound such as adipindialdehyde, maleic dialdehyde, phthalaldehyde, isophthalaldehyde, terephthalaldehyde or an acetal compound of dialdehyde can also be used as a crosslinking agent. In the case of a dialdehyde compound, an aldehyde group reacts with a hydroxyl group in polyvinyl acetal by the action of a catalyst or forms an acetal bond by an acetal exchange reaction with an alkyl acetal group. The dialdehyde compound or the acetal compound of dialdehyde may be used alone, or two or more compounds may be used as a mixture. The addition amount of the dialdehyde compound or the acetal compound in the intermediate layer coating solution is 0.01 to 30% by weight,
The content is preferably 0.1 to 20% by weight, and when used in a mixture with the organosilane compound and the organotitanium compound, the content is preferably 50 mol% or less of the organosilane compound and the organotitanium compound.

As a curing catalyst, in a system using a hydrolyzable organosilane compound and an organotitanium compound as a crosslinking agent, dehydration condensation between silanol groups and titanol groups formed by hydrolysis and hydroxyl groups in polyvinyl acetal is promoted. In a system using a dialdehyde compound or an acetal compound of a dialdehyde as a catalyst, there is no particular limitation as long as it promotes an acetalization reaction between an aldehyde group and a hydroxyl group in polyvinyl acetal. The catalyst may be used alone, or a mixture of two or more catalysts may be used. The addition amount of the acidic catalyst in the intermediate layer coating solution is 0.002 to 20% by weight, preferably 0.005 to 5% by weight. In addition, it is effective to use a solid catalyst. Examples of the solid catalyst include metals, metal oxides and metal sulfides, sulfates, carbonates, and the like, but any catalyst having the above-described catalytic ability may be used. The catalyst may be used alone, or a mixture of two or more catalysts may be used. Further, it may be used by mixing with an acidic catalyst. The addition amount of the metal catalyst in the intermediate layer coating solution is 0.001 to 10% by weight, preferably 0.005 to 5% by weight.

In addition, pure water, a leveling agent, a functional material and the like can be added. For example, various leveling agents for the purpose of improving the surface state at the time of coating the intermediate layer, or an ultraviolet absorber or an antioxidant for improving the weather resistance, and also a normal dye,
Pigments, photochromic dyes and the same pigments can be mentioned. Under the above conditions, an intermediate layer coating solution containing an appropriate amount of the metal oxide fine particles and having a refractive index adjusted to be an intermediate value between the plastic lens substrate and the hard coat layer is prepared, and spin-coated on the plastic lens. The film is formed by a coating method or a dipping method. The film thickness at that time is usually 0.1.
It is about 5 to 3 microns. The intermediate layer may be a single layer, but when the difference between the refractive indices of the plastic lens substrate and the hard coat layer is large, a plurality of intermediate layers having slightly different refractive indices may be sequentially laminated.

Before the application of the intermediate layer coating liquid, various pretreatments may be applied to the plastic lens in order to improve the adhesion of the intermediate layer to the plastic lens. Examples of the pretreatment include a saponification treatment, a plasma treatment, and a surface treatment with ultraviolet rays. In the saponification treatment, the plastic lens is immersed in an aqueous solution of about 10% by weight of sodium hydroxide at about 60 ° C. for about 5 minutes. Washing is performed in a washing process composed of pure water or the like. On the other hand, plasma treatment is to place the plastic lens surface in contact with oxygen plasma,
In this method, the surface of the plastic is reacted with oxygen ions or oxygen radicals in the plasma to modify the surface. Further, the surface treatment with ultraviolet rays is a treatment for exposing a plastic lens to ultraviolet rays such as a mercury lamp to improve the hydrophilicity of the surface.

On the intermediate layer, a hard coat layer for improving scratch resistance is provided. In general, as a method for forming a hard coat layer, an organic silicon-based hard coating technique under wet conditions has been put to practical use. The composition of the hard coat liquid is composed of a hydrolyzate of an organoalkoxysilane, metal oxide fine particles, and a metal complex catalyst.The film forming method includes a dipping method and a spin coating method. Let it cure. In addition, treatment under dry conditions is also possible. Conventionally, the refractive index of the hard coat layer must be completely matched to the refractive index of the plastic substrate or adjusted to a very close value even if it does not match, as the type of plastic lens substrate increases Therefore, it was necessary to prepare various kinds of coating liquids. However, according to the present invention, it has become possible to apply one type of hard coat to various plastic substrates.

On the hard coat layer, if necessary,
An anti-reflection coat can be applied. As the antireflection coat, a film having a single layer or a multilayer structure based on optical theory is employed. Materials include SiO, SiO ₂ , A
l ₂ O ₃ , Y ₂ O ₃ , Yb ₂ O ₃ , CeO ₃ , Ta ₂ O ₃ , Ti
Inorganic dielectrics such as O ₂ , MgF ₂ , ZrO ₂ are used,
It is common to form a film by a vacuum deposition method, a sputtering method, an ion plating method, or the like.

Further, if necessary, an organic layer having a hydrophobic group such as an alkyl group, a phenyl group or a polyfluoroalkyl group in a side chain may be provided on the upper layer of the antireflection coating layer for the purpose of preventing stain adhesion and preventing water scorching. It is also possible to form an ultra-thin film of a silicon compound or a fluorine-containing hydrocarbon compound. In addition, by imparting additional functions such as shock absorption to the intermediate layer, excellent impact resistance, scratch resistance, excellent wear resistance,
It is possible to provide an inexpensive plastic lens having a good appearance. In particular, when a crosslinked polyvinyl acetal is used, the improvement in impact resistance becomes remarkable.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

[0034]

Example 1 (1-1) Preparation of Coating Solution for Intermediate Layer A commercially available degree of butyralization of about 25% and an average degree of polymerization of 2,400
Polyvinyl butyral resin (Wako Pure Chemical Industries, Ltd.) 70
Parts by weight of n-butanol was dissolved in 630 parts by weight of n-butanol.
) Is gradually added with stirring. Further, 100 parts by weight of water, 8.5 parts by weight of methyltrimethoxysilane as a cross-linking agent, 1.2 parts by weight of p-toluenesulfonic acid as a curing catalyst, and Florad FC4 as a leveling agent
301 parts by weight were sequentially added, and the mixture was sufficiently stirred until the mixture became homogeneous. Then, the mixture was filtered through a 0.2 μm membrane filter to prepare a coating solution for an intermediate layer.

(1-2) Measurement of Refractive Index and Measurement of Film Thickness of Intermediate Layer The coating solution prepared in the above 1-1 was applied to a plastic plate for glasses having a refractive index of 1.66, and then placed in a heating furnace.
Heat at 0 ° C. for 30 minutes. When the spectral reflectance of the obtained sample is measured in the wavelength range of 400 nm to 800 nm, the reflectance shows a periodic change according to the wavelength. However, coating was performed from the peaks and valleys of the reflectance curve at this time. The refractive index and the film thickness of the film could be measured. The refractive index of the intermediate layer in this example was 1.55, and the film thickness was 1 μm.

(1-3) A plastic lens for spectacles (Nikon NLII) having a coating and curing degree of the intermediate layer coating liquid of -3.00 diopter, a center thickness of 1.0 mm and a refractive index of 1.60.
First, plasma treatment was performed for the purpose of enhancing the adhesion of the intermediate layer. The plasma processing was performed using "Plasma Reactor PR501A" manufactured by Yamato Scientific Co., Ltd., at an oxygen gas pressure of about 0.2 Torr, an RF output of 200 W, and a processing time of 30 seconds. Thereafter, the intermediate layer coating solution prepared in the above 1-1 was applied to both surfaces of the plastic lens by a spin coating method. Spin coating conditions: primary rotation speed 500
The rotation speed was 5 seconds at rpm, the rotation speed at 2,000 rpm for 10 seconds, and the primer film thickness was approximately 1 μm. afterwards,
The high refractive index plastic lens coated with the intermediate layer coating solution was placed in a heating furnace and heated at 80 ° C. for 30 minutes to cure the intermediate layer.

(1-4) Preparation of Hard Coating Solution Silane Coupling Agent (Sila Ace, manufactured by Chisso Corporation)
180 ml was stirred and 50 ml of 0.001N hydrochloric acid aqueous solution was added.
Was added and further stirred. Next, methanol silica sol 6
80 ml was added and stirring was continued. Finally, after adding a small amount of a surfactant using a small amount of iron acetylacetone as a catalyst, the mixture was stirred for 1 hour or more, and then stored in a cool place.

(1-5) Measurement of Refractive Index and Measurement of Film Thickness of Hard Coat Film
The refractive index measurement and the film thickness measurement of the hard coat film were performed in the same manner as in Example-2. However, the time of the heat treatment was 4 hours. As a result, the refractive index was 1.49 and the film thickness was 1.2 μm. (1-6) Application and curing of hard coat liquid The hard coat liquid obtained in 1-4 above was dipped on both surfaces of the plastic lens having the intermediate layer obtained in 1-3 above (dipping speed 100 cm / min). ). The coated lens was heated at 80 ° C. for 4 hours to cure the hard coat layer.

(1-7) Formation of Antireflection Coat A four-layer antireflection coat was formed on both surfaces of the plastic lens having the intermediate layer and the hard coat layer obtained in 1-6 by a vacuum EB evaporation method. (1-8) Performance Evaluation of Plastic Lens The plastic lens having the composite film obtained in 1-7 above was subjected to the following tests to evaluate the performance. The evaluation results are shown in Table 1.

1) Scratch resistance The surface of the plastic lens was coated with steel wool (# 000).
In 0), the degree of scratching when rubbing 30 times by applying a load of 400 g was evaluated according to the following criteria. A: The area with the scratch is within 10%. B: The area with the scratch exceeds 10% and is within 30%.

C: The area with the damage is 30% or more. 2) Impact resistance The impact resistance of the plastic lens was evaluated by a hard ball drop test. Using a 20.0 g hard ball that is about 26% heavier than the conditions specified by the FDA, let it fall naturally from the height of 127 cm toward the center of the plastic lens, and before the plastic lens cracks or cracks one time The number of times was used as a measure of the impact resistance of the lens, and the lens was dropped up to five times.

3) Interference fringes In a dark room, light from a fluorescent lamp was applied to a plastic lens, and the degree of interference fringes due to reflection was visually evaluated. The evaluation was performed according to the following criteria. A: Almost no interference fringes can be seen. B: Some interference fringes are visible, but not to a degree that poses a practical problem.

C: Interference fringes are conspicuous, which is not preferable for practical use.

[0044]

Example 2 (2-1) Preparation of Coating Solution for Intermediate Layer 70 parts by weight of a commercially available polyvinyl butyral resin (manufactured by Wako Pure Chemical Industries, Ltd.) having a butyralization degree of about 70% and an average degree of polymerization of 700 was mixed with n-butanol 630. 120 parts by weight of a composite sol of a particulate inorganic substance composed of tin oxide and a particulate inorganic substance composed of tungsten oxide (manufactured by Nissan Chemical Industries, Ltd., methanol solvent dispersion) are gradually added. The addition was performed gradually with stirring, and a rotor and a magnetic stirrer were used for stirring. And 100 parts by weight of water,
8.5 parts by weight of methyltrimethoxysilane as a cross-linking agent, 1 part by weight of glutaraldehyde, 1.2 parts by weight of p-toluenesulfonic acid as a curing catalyst, and 1 part by weight of Florad FC430, a silicon-based surfactant as a leveling agent. In addition, the mixture was sufficiently stirred until it became homogeneous, and then filtered through a 0.2 μm membrane filter.
A primer composition for coating was prepared.

(2-2) Measurement of Refractive Index and Measurement of Film Thickness of Intermediate Layer The coating solution prepared in 2-1 was applied to a plastic plate for glasses having a refractive index of 1.66, and then placed in a heating furnace.
Heat at 0 ° C. for 30 minutes. When the spectral reflectance of the obtained sample is measured in the wavelength range of 400 nm to 800 nm, the reflectance shows a periodic change according to the wavelength. However, coating was performed from the peaks and valleys of the reflectance curve at this time. The refractive index and the film thickness of the film could be measured. The refractive index of the intermediate layer in this example was 1.58, and the film thickness was 1 μm.

(2-3) Plastic lens for spectacles (Nikon NLI) having a coating and curing degree of the intermediate layer coating liquid of -3.00 diopter, a center thickness of 1.0 mm and a refractive index of 1.66.
V) First, plasma treatment was performed for the purpose of enhancing the adhesion of the intermediate layer. The plasma processing was performed using "Plasma Reactor PR501A" manufactured by Yamato Scientific Co., Ltd., with an oxygen gas pressure of about 0.2 Tool, an RF output of 200 W, and a processing time of 30 seconds. Thereafter, the intermediate layer coating solution prepared in the above 2-1 was applied to both surfaces of the plastic lens by a spin coating method. Spin coating conditions: primary rotation speed 500
The rotation speed was 5 seconds at rpm, the rotation speed at 2,000 rpm for 10 seconds, and the primer film thickness was approximately 1 μm. afterwards,
The high refractive index plastic lens coated with the intermediate layer coating solution was placed in a heating furnace and heated at 80 ° C. for 30 minutes to cure the intermediate layer.

(2-4) Preparation of Hard Coating Solution A hard coating solution was prepared in the same manner as in 1-4 of Example 1. (2-5) Refractive index measurement and film thickness measurement of hard coat film The refractive index measurement and film thickness measurement of the hard coat film were performed in the same manner as in 1-5 of Example 1. As a result, the refractive index is 1.
49, and the film thickness was 1.0 μm.

(2-6) Application and Hardening of Hard Coat Solution The hard coat solution obtained in 2-4 was dipped on both sides of the plastic lens having the intermediate layer obtained in 2-3 above by a dipping method (pulling speed). (100 cm / min). The coated lens was heated at 80 ° C. for 4 hours to cure the hard coat layer.

(2-7) Formation of Antireflection Coat A four-layer antireflection coat was formed by vacuum EB evaporation on both surfaces of the plastic lens having the intermediate layer and the hard coat layer obtained in 2-6 above. (2-8) Performance Evaluation of Plastic Lens Using the plastic lens having the composite film obtained in 2-7 above, performance evaluation was performed in the same manner as in 1-8 of Example 1. The evaluation results are shown in Table 1.

[0050]

Example 3 (3-1) Preparation of Coating Solution for Intermediate Layer The same procedure as in Example 1-1 was carried out. (3-2) Measurement of Refractive Index and Film Thickness of Intermediate Layer The coating solution prepared in 1-1 was applied to a plastic flat plate for glasses having a refractive index of 1.66, and then 1-2 in Example 1 was measured.
The refractive index and the film thickness of the applied film were measured using the same method as described above. The refractive index of the intermediate layer in this example was 1.55, and the film thickness was 0.8 μm.

(3-3) Plastic lens for spectacles (CR39) having a coating and curing degree of the intermediate layer coating liquid of -3.00 diopter, a center thickness of 1.0 mm and a refractive index of 1.50.
First, saponification treatment was performed for the purpose of strengthening the adhesion of the intermediate layer. The saponification treatment was performed by immersing the plastic in a 10% aqueous sodium hydroxide solution heated to 60 ° C. for 5 minutes. Thereafter, the intermediate layer coating solution prepared in 3-1 was applied to both surfaces of the plastic lens by spin coating. Spin coating conditions: primary rotation speed 5
The speed was set to 00 rpm for 5 seconds, the secondary rotation speed was set to 2,000 rpm for 10 seconds, and the primer film thickness was set to approximately 1 μm. Thereafter, the high refractive index plastic lens coated with the intermediate layer coating solution is placed in a heating furnace and heated at 80 ° C. for 30 minutes.
The intermediate layer was cured.

(3-4) Preparation of Hard Coating Solution In a reaction vessel equipped with a rotor, 180 parts by weight of γ-glycidoxypropyltrimethoxysilane was charged, and the mixture was stirred thoroughly with a magnetic stirrer. .0
40 parts by weight of a 1 N hydrochloric acid aqueous solution was added all at once. Immediately after the addition, the solution was a heterogeneous solution, but became a uniform and transparent solution while generating heat within a few minutes. The mixture was further stirred for one hour for hydrolysis to obtain a partially condensed hydrolyzate.

A commercially available tin oxide sol (methanol dispersion, average particle diameter 10 to 15 nm) was added to the above hydrolyzate in 6 parts.
30 parts by weight, 4 parts by weight of aluminum ethylenediaminetetraacetate as a curing catalyst, and 0.45 parts by weight of Florad FC430, a silicon-based surfactant as a leveling agent, were sufficiently stirred, and then filtered through a 3 μm membrane filter. Then, a hard coat liquid was prepared.

(3-5) Measurement of Refractive Index and Film Thickness of Hard Coat Film The coating liquid prepared in the above 3-4 was applied to a plastic plate for spectacles having a refractive index of 1.50, and then Example 1-1-1 5
The measurement was performed in the same manner as described above. The refractive index of the hard coat layer of this example was 1.61, and the film thickness was 0.8 μm. (3-6) Application and curing of hard coat liquid The hard coat liquid obtained in 3-4 was dipped on both surfaces of the plastic lens having the intermediate layer obtained in 3-3 above (dipping speed: 100 cm / min). ). The coated lens was heated at 80 ° C. for 4 hours to cure the hard coat layer.

(3-7) Formation of Antireflection Coat A four-layer antireflection coat was formed on both surfaces of the plastic lens having the intermediate layer and the hard coat layer obtained in 3-6 by a vacuum EB evaporation method. (3-8) Performance Evaluation of Plastic Lens Using the plastic lens having the composite film obtained in 3-7, performance evaluation was performed in the same manner as in 1-8 of Example 1. The evaluation results are shown in Table 1.

[0056]

Example 4 (4-1) Preparation of Coating Solution 1 for Intermediate Layer 70 parts by weight of a commercially available polyvinyl butyral resin (manufactured by Wako Pure Chemical Industries, Ltd.) having a butyralization degree of about 70% and an average polymerization degree of 700 were added to n-butanol. After dissolving in 630 parts by weight, 140 parts by weight of a composite sol of a particulate inorganic substance composed of tin oxide and a particulate inorganic substance composed of tungsten oxide (manufactured by Nissan Chemical Industries, Ltd., methanol solvent dispersion) are gradually added. The addition was performed gradually with stirring, and a rotor and a magnetic stirrer were used for stirring. And 100 parts by weight of water,
8.5 parts by weight of methyltrimethoxysilane as a cross-linking agent, 1 part by weight of glutaraldehyde, 1.2 parts by weight of p-toluenesulfonic acid as a curing catalyst, and 1 part by weight of Florad FC430, a silicon-based surfactant as a leveling agent. In addition, the mixture was sufficiently stirred until it became homogeneous, and then filtered through a 0.2 μm membrane filter.
A primer composition for coating was prepared.

(4-2) Measurement of Refractive Index and Measurement of Film Thickness of Intermediate Layer 1 The coating liquid 1 prepared in 4-1 was applied to a plastic flat plate for spectacles having a refractive index of 1.50. The same measurement as in Example-2 was performed. The refractive index of the intermediate layer 1 of this example was 1.60, and the film thickness was 1 μm. (4-3) Plastic lens for spectacles (Nikon NLI) having a coating and curing frequency of the intermediate layer coating liquid 1 of -3.00 diopter, a center thickness of 1.0 mm and a refractive index of 1.66.
V) First, plasma treatment was performed for the purpose of enhancing the adhesion of the intermediate layer. The plasma processing was performed using "Plasma Reactor PR501A" manufactured by Yamato Scientific Co., Ltd., at an oxygen gas pressure of about 0.2 Torr, an RF output of 200 W, and a processing time of 30 seconds. Thereafter, the intermediate layer coating solution 1 prepared in 4-1 was applied to both surfaces of the plastic lens by spin coating. Spin coating conditions: primary rotation speed 50
The rotation speed was set to 0 rpm for 5 seconds, the secondary rotation speed was set to 2,000 rpm for 10 seconds, and the primer film thickness was set to approximately 1 μm. afterwards,
The high refractive index plastic lens coated with the intermediate layer coating liquid 1 was placed in a heating furnace and heated at 80 ° C. for 30 minutes to cure the intermediate layer.

(4-4) Preparation of Coating Solution 2 for Intermediate Layer 70 parts by weight of a commercially available polyvinyl butyral resin (manufactured by Wako Pure Chemical Industries, Ltd.) having a degree of butyralization of about 70% and an average degree of polymerization of 700 were mixed with 630 parts by weight of n-butanol. Then, 60 parts by weight of a composite sol of a particulate inorganic substance composed of tin oxide and a particulate inorganic substance composed of tungsten oxide (manufactured by Nissan Chemical Industries, Ltd., methanol solvent dispersion) are gradually added. The addition was performed gradually with stirring, and a rotor and a magnetic stirrer were used for stirring. Further, 100 parts by weight of water, 8.5 parts by weight of methyltrimethoxylane and 1 part by weight of glutaraldehyde as a crosslinking agent, 1.2 parts by weight of p-toluenesulfonic acid as a curing catalyst, and a silicon-based surfactant as a leveling agent. 1 part by weight of Florade FC430 was added in order, and the mixture was sufficiently stirred until the mixture became homogeneous. Then, the mixture was filtered through a 0.2 μm membrane filter to prepare a primer composition for coating.

(4-5) Measurement of Refractive Index and Measurement of Film Thickness of Intermediate Layer 2 The intermediate layer coating liquid 2 prepared in the above 4-4 was applied with a refractive index of 1.6.
Example 1 after application to the plastic plate for glasses of No. 6
The same measurement as 1-2 was performed. The refractive index of the intermediate layer 1 of this example was 1.55, and the film thickness was 1 μm. (4-6) Application and curing of intermediate layer coating liquid 2 On the plastic lens on which intermediate layer 1 was applied in 4-3, the intermediate layer coating liquid 2 prepared in 4-4 was further applied by spin coating. Applied. Spin coating conditions: primary rotation speed 500 rpm for 5 seconds, secondary rotation speed 2,000 rpm
For 10 seconds, and the primer film thickness was approximately 1 μm. Thereafter, the high refractive index plastic lens coated with the intermediate layer coating liquid 2 was placed in a heating furnace, and heated at 80 ° C. for 30 minutes to cure the intermediate layer 2.

(4-7) Preparation of Hard Coat Solution A hard coat solution was prepared in the same manner as in 1-4 of Example 1. (4-8) Refractive Index Measurement and Film Thickness Measurement of Hard Coat Film The refractive index measurement and the film thickness measurement of the hard coat film were performed in the same manner as in 1-5 of Example 1. As a result, the refractive index is 1.
49, and the film thickness was 1.0 μm.

(4-9) Application and Hardening of Hard Coat Solution The hard coat solution obtained in 4-7 is applied to both surfaces of the plastic lens having the intermediate layer 1 and the intermediate layer 2 obtained in 4-6 above. Dipping method (pulling speed 100cm
/ Min). Apply the coated lens at 80 ° C for 4
The heat treatment was performed for a time to cure the hard coat layer.

(4-10) Formation of Antireflection Coat A four-layer antireflection coat is formed on both surfaces of the plastic lens having the intermediate layer 1, the intermediate layer 2, and the hard coat layer obtained in 4-9 by vacuum EB evaporation. It was formed by a method. (4-11) Performance evaluation of plastic lens Using the plastic lens having the composite film obtained in 4-10 above, performance evaluation was performed in the same manner as in 1-8 of Example 1. The evaluation results are shown in Table 1. Comparative Example 1 The same procedure as in Example 1 was carried out except that the plastic lens was not provided with an intermediate layer. In addition, all evaluation methods were the same as in Example 1.
The evaluation results are shown in Table 1. Comparative Example 2 The same procedure as in Example 2 was carried out except that the plastic lens was not provided with an intermediate layer. In addition, all evaluation methods were the same as in Example 2.
The evaluation results are shown in Table 1. Comparative Example 3 The same procedure as in Example 3 was carried out except that the plastic lens was not provided with an intermediate layer. All evaluation methods were the same as in Example 3.
The evaluation results are shown in Table 1.

[0063]

[Table 1]

[0064]

According to the present invention, it is possible to suppress interference fringes without changing the properties of the hard coat layer, there is no practical problem of interference fringes, the appearance is excellent, the scratch resistance, A plastic lens having excellent wear properties can be obtained. Also, if a material having excellent impact resistance such as cross-linked polyvinyl acetal is used as the material for forming the intermediate layer, an interference fringe-free appearance having durability such as impact resistance, scratch resistance, and abrasion resistance can be obtained. An excellent plastic lens can be obtained.

In the present invention, the amount of metal fine particles used for adjusting the refractive index may be smaller than the amount of metal fine particles conventionally added to the hard coat layer. Accordingly, since the amount of expensive fine particles used is reduced, it is possible to manufacture a lens at low cost. This is particularly noticeable in the production of high refractive index lenses using expensive titanium oxide fine particles and tin oxide fine particles.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a plastic lens having a single intermediate layer according to the present invention.

FIG. 2 is a schematic side view of a plastic lens having a multilayer intermediate layer according to the present invention.

[Explanation of symbols]

 1 ... Hard coat layer 2, 3, 4, 5 ... Intermediate layer 6 ... Plastic lens substrate

Claims (5)

[Claims] 1. A plastic lens having a plastic lens substrate, an intermediate layer having a single-layer structure formed on the plastic lens substrate, and a hard coat layer formed on the intermediate layer. A plastic lens, wherein a refractive index, a refractive index of the intermediate layer, and a refractive index of the hard coat layer decrease from the substrate side toward the hard coat layer side. 2. The method according to claim 1, wherein a difference in refractive index between the plastic lens substrate and the intermediate layer and a difference in refractive index between the intermediate layer and the hard coat layer are each less than about 0.1. The plastic lens according to 1. 3. The plastic lens according to claim 1, wherein the intermediate layer having the single-layer structure has a multilayer structure. 4. The difference in refractive index between the layers in the intermediate layer of the multilayer structure is substantially 0.1, the difference in the refractive index between the plastic lens substrate and the intermediate layer adjacent to the plastic lens substrate, and The difference in the refractive index between the coat layer and the intermediate layer adjacent to the hard coat layer is smaller than approximately 0.1, and the refractive index is gradually reduced from the substrate side toward the hard coat layer. The plastic lens according to claim 3, wherein: 5. The plastic lens according to claim 1, wherein the intermediate layer is mainly composed of a polyvinyl acetal resin and / or a polymer thereof.