JPH0435725B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical material having an antireflection layer and a method for producing the same.

[Conventional technology]

Generally, optical lenses such as eyeglass lenses and camera lenses, as well as other plastic optical materials, are required to have anti-reflection properties.In particular, eyeglass lenses are required to have a hard coating to prevent scratches. In addition to the layer, to prevent the formation of reflected images called ghosts and flares,
Antireflection layers consisting of a single layer or multiple layers have been formed.

Conventionally, anti-reflection layers have been formed directly on the surface of a substrate made of glass or plastic, or by depositing organic substances on the surface of the substrate, using vapor deposition methods such as vacuum evaporation, sputtering, ion plating, and CVD. A method is known in which a hard coat layer or a primer coat layer is formed and then silica or other inorganic material is deposited on the hard coat layer or primer coat layer.

However, in the method of forming an antireflection layer by such a vapor deposition method, in addition to the disadvantages of low productivity and high cost, there is also the problem that the characteristics of the substrate are not expressed or are impaired. There is. For example, when the substrate is a plastic substrate, the substrate itself has dyeability, but the dyeability is lost due to the formation of an anti-reflection layer by vapor deposition, and the harsh conditions for vapor deposition As a result, the impact resistance of the plastic substrate is significantly reduced. Furthermore, although vapor deposition methods require heating the substrate to, for example, 300° C. or higher, plastic substrates cannot be heated to such high temperatures. However, when vapor deposition is performed at a low heating temperature, the formed vapor deposited film has insufficient adhesion to the substrate.

In addition, when a hard coat layer or a primer coat layer made of an organic substance is formed on the surface of the substrate, their durability and heat resistance are low, so it is difficult to form an antireflection layer on top of it by vapor deposition. However, there is a problem in that cracks and peeling of the antireflection layer occur relatively early.

On the other hand, instead of using the above vapor deposition method, a material made of an organic or inorganic material is applied to the surface of the substrate by a dipping method, spin coating method, spray coating method, etc., thereby forming a single layer. Alternatively, many methods for forming multilayer antireflection layers have been proposed, such as JP-A-59-49501, JP-A-59-49502, JP-A-60-68319, and JP-A-60-60. Publication No. 213901 and the like describe the formation of an antireflection layer consisting of a coating made of a silicon-containing compound or a coating made by dispersing fine silica powder.

[Problem to be solved by the invention]

The above anti-reflection layer utilizes the low refractive properties of silicon oxide, but the refractive index of silicon oxide is 1.46.
However, it is not sufficiently low, and therefore, there is a problem in that it is not necessarily possible to obtain an excellent antireflection effect.

[Purpose of the invention]

An object of the present invention is to provide an optical material having an antireflection layer that has a sufficiently low refractive index and exhibits an excellent antireflection effect.

Another object of the present invention is to provide a method that can advantageously produce an optical material having an antireflection layer as described above.

[Summary of the invention]

The optical material having an antireflection layer of the present invention comprises a transparent plastic substrate with a refractive index of 1.48 or more, and an inorganic microorganism made of magnesium fluoride with an average particle size of 0.3 to 200 nm, which is formed to cover the surface of the plastic substrate. It is characterized by comprising a powder dispersed in a binder and an antireflection layer having a thickness of 50 to 5000 nm and having a refractive index lower by 0.02 or more than the plastic substrate.

In the manufacturing method of the present invention, particles with an average particle diameter of 0.3 are coated on the surface of a transparent plastic substrate with a refractive index of 1.48 or more.
An antireflection layer forming coating solution containing an inorganic fine powder of magnesium fluoride of ~200 nm and a binder material is applied, and the inorganic fine powder is dispersed in the binder, and the anti-reflection layer is 0.02 or more lower than the plastic substrate. Thickness 50~5000nm with refractive index
It is characterized by forming an antireflection layer.

[Specific description of the invention]

The present invention will be specifically explained below.

In the present invention, a transparent plastic substrate having a refractive index of 1.48 or more is used as the substrate on which the antireflection layer is formed. As long as such a plastic base is used, the material is not limited, and for example, those made of polymethyl methacrylate, polycarbonate, polystyrene, diethylene glycol bisallyl carbonate, cellulose acetate, and other resins can be used. , various acrylate copolymers, methacrylate copolymers, polymers containing aromatic bromine compounds, polyurethane, etc. that have been proposed as high refractive index materials can also be used.

The plastic substrate used in the present invention must have a refractive index of 1.48 or more; if a plastic substrate with a refractive index of less than 1.48 is used, the antireflection effect may not be substantially achieved. When a plastic substrate with a refractive index of 1.54 or more is used, a sufficiently excellent antireflection effect can be obtained.

Thus, the refractive index of the plastic substrate is 1.48
However, in the present invention, when an antireflection layer is formed on a plastic material having a relatively low refractive index, for example, a refractive index of 1.53 or less, the refractive index is but
A surface layer made of a transparent organic material having a refractive index of 1.48 or more, preferably 1.53 or more can be formed, thereby controlling the refractive index of the surface portion, and this can be used as a plastic substrate. Preferably, this surface layer has a refractive index similar to that of the plastic material. This surface layer can also be formed to have properties as a hard coat layer.

The plastic substrate used in the present invention may be of any shape as long as it can be shaped according to the final purpose of use; for example, it may be shaped as an optical material such as various lenses, or it may be a flat plate, It may have another form and be later processed into the form of an optical material. Such a plastic substrate can be manufactured by injection molding, cast polymerization, or the like.

In the present invention, an antireflection layer is formed to cover the surface of the plastic substrate. This antireflection layer is made by dispersing inorganic fine powder, mainly consisting of fine magnesium fluoride powder, in a binder. This inorganic fine powder may be composed only of fine magnesium fluoride powder, or may be mainly composed of fine magnesium fluoride powder and may contain fine powder of other inorganic substances.

The magnesium fluoride fine powder used here has an average particle size of 0.3 to 200 nm.
Particularly preferred is a fine powder of 0.5 to 100 nm. Magnesium fluoride fine powder with an average particle size of less than 0.3 nm is difficult to manufacture, resulting in high costs and is not practical.On the other hand, when using one with an average particle size of more than 200 nm, the anti-reflection that is formed The transparency of the layer decreases.

Examples of fine inorganic powders used together with fine magnesium fluoride powder include silica (SiO ₂ ,
Refractive index 1.46), aluminum fluoride (AlF ₃ , refractive index 1.33-1.39), calcium fluoride (CaF ₂ , refractive index 1.44), lithium fluoride (LiF, refractive index 1.36-1.39)
1.37), sodium fluoride (NaF, refractive index 1.32~
1.34) and thorium fluoride (ThF ₄ , refractive index 1.45)
~1.5). These fine powders preferably have an average particle diameter of 0.3 to 200 nm, and one or more of them can be used.

When the fine powders of the above inorganic substances are used together, it is preferable that the fine magnesium fluoride powder accounts for 50% by weight or more of the whole fine inorganic powders.

The above-mentioned inorganic fine powder mainly composed of magnesium fluoride is dispersed in a binder described later to form an antireflection layer. The refractive index of this antireflection layer must be 0.02 or more lower than that of the plastic substrate, and if the difference in refractive index is not 0.02 or more, excellent antireflection effects cannot be obtained.
Further, the proportion of the inorganic fine powder mainly composed of magnesium fluoride in the antireflection layer is preferably 3% by weight or more, particularly 5% by weight or more of the entire antireflection layer, from the viewpoint of scratch resistance.

In the present invention, the antireflection layer is formed as follows. That is, a coating solution for forming an antireflection layer is prepared by mixing the above-mentioned inorganic fine powder mainly composed of magnesium fluoride with a binder material and a necessary dispersion medium, and this is coated on the surface of a plastic substrate, and then heated. The antireflection layer is formed by curing the antireflection layer by a curing process such as the following.

As the binder, a resin having film-forming properties can be used. Examples of such resins include acrylic resin, polyurethane resin, melamine resin, epoxy resin, polyester resin,
Thermoplastic resins or thermosetting resins such as polyamide resins, alkyd resins, vinyl chloride resins, fluorine resins, and silicone resins are used. When a thermosetting resin is used as the binder, a precursor of the resin is used as the material, and a coating liquid for forming an antireflection layer is prepared using this.

In addition to the above-mentioned resins, in the present invention, metal alkoxides that form a film that hardens upon heating can be used as a binder, and since an antireflection layer with a particularly low refractive index is formed, silane alkoxides can be used. is preferred. As the silane alkoxide, alkoxysilane or carbon functional polyorganosiloxane is used.

Specific examples of alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyl Triethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxysilane, propyltributoxysilane, dimethyldimethoxysilane,
Dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane,
Examples include diethyldipropoxysilane, diethyldibudoxysilane, methylethyldimethoxysilane, and methylpropyldiethoxysilane.

Examples of the carbon functional polyorganosiloxane include 3,4-epoxycyclohexylalkyltrialkoxysilane, methacryloxyalkyltrialkoxysilane, vinyltrialkoxysilane, γ-glycidoxyalkyltrialkoxysilane, and aminoalkyltrialkoxysilane. There is.

The above-mentioned binder material is dispersed or dissolved in a dispersion medium in which inorganic fine powder mainly composed of magnesium fluoride is dispersed in the coating liquid for forming an antireflection layer. In particular, when the binder is a silane alkoxide, it can be mixed in a dispersion medium consisting of an inorganic fine powder mainly composed of magnesium fluoride and an organic solvent, or a part of it can be further hydrolyzed into an oligomer form and aged. Accordingly, a suitable coating liquid for forming an antireflection layer can be obtained.

In order to facilitate the preparation of the coating solution for forming an antireflection layer, the inorganic fine particles mainly composed of magnesium fluoride may be subjected to a hydrophilic treatment or a hydrophobic treatment, if necessary.

The coating solution for forming an antireflection layer is made by uniformly dispersing the above-mentioned inorganic fine powder and binder in a dispersion medium consisting of water or an organic solvent at an appropriate concentration so that it can be easily applied to a plastic substrate. It is assumed that the In order to achieve particularly uniform application, it is preferable to use an organic solvent as a dispersion medium.

Examples of organic solvents used as dispersants include alcohols, ketones, esters, halogenated hydrocarbons, and ethers, particularly methyl alcohol, ethyl alcohol, butyl alcohol,
Alcohols such as n-propyl alcohol and isopropyl alcohol are preferably used.

It is also possible to further add a flow control agent, an ultraviolet absorber, an antioxidant, etc. to the coating solution for forming an antireflection layer in order to improve the surface smoothness of the coating film.

Such a coating solution for forming an anti-reflection layer is applied to the surface of a plastic substrate using a normal dipping method or spin coating method, and the formed coating film is cured to form an anti-reflection film. Ru.

When applying the coating solution for forming an antireflection layer, it is preferable to pre-treat the surface of the plastic substrate, thereby improving the adhesion of the antireflection layer to the plastic substrate.

Such pretreatment includes chemical treatment, activated gas treatment, and the like. Chemical treatment is generally acid or alkali treatment. Also,
Activated gas treatments include corona discharge treatment and low-temperature plasma treatment, and treatments using ultraviolet rays and ozone are also effective. A plurality of these pretreatments can be carried out continuously, in stages, or in parallel.

Generally, when forming a single-layer antireflection layer on the surface of a transparent substrate, the refractive index of the substrate is n ₀ ,
If the refractive index of the antireflection layer is n ₁ , its layer thickness is d ₁ , and the design wavelength is λ, then when n ₁ · d ₁ = λ/4 or an odd multiple thereof, the phase difference for vertically incident light becomes 180 degrees, and the intensity of reflected light due to interference becomes minimum. This is called the phase condition. Here, (n ₁ ·d ₁ ) is called the optical film thickness, and once the refractive index of the substance and the design wavelength λ are determined, the specific thickness of the antireflection layer is designed. Here, the design wavelength λ is generally selected from the visible wavelength range of 300 to 800 nm depending on the purpose.

Further, the reflectance is minimum when the refractive index of the antireflection layer is equal to the square root of the refractive index of the substrate, that is, when n ₁ =√ ₀ . This is called the amplitude condition.

Therefore, it is preferable to satisfy these two conditions as much as possible by appropriately selecting the material used to form the antireflection layer and controlling the refractive index and thickness of the antireflection layer.

The smaller the thickness of the antireflection layer, the easier it is to realize the phase conditions, which is desirable for achieving the antireflection effect. On the other hand, since the antireflection layer actually forms the outermost surface of the optical material, it is practically essential that it has a certain degree of hardness, and in order to achieve this, the antireflection layer must have a large thickness. It is desirable that the From this point of view, in the present invention, the thickness of the antireflection layer is within the range of 50 to 5000 nm, preferably 100 to 3000 nm.

By appropriately selecting the material used to form the antireflection layer, it is possible to improve various properties of the antireflection layer, such as adhesion to a plastic substrate and scratch resistance.

〔effect〕

The optical material having an antireflection layer of the present invention has an antireflection layer formed to cover a plastic substrate, in which fine inorganic powder mainly composed of fine magnesium fluoride powder is dispersed in a binder, and the antireflection layer is formed to cover a plastic substrate. Magnesium chloride has an extremely low refractive index of 1.38, which provides excellent antireflection effects. In addition, the average particle size of magnesium fluoride fine powder is
Since the particles have a very small particle size of 0.3 to 200 nm, sufficient transparency can be obtained in the antireflection layer formed. Furthermore, since this anti-reflection layer is formed from a binder made of organic substances, it can be dyed, has excellent scratch resistance and durability, and has high adhesion to plastic substrates. Obtainable.

In addition, in order to form an anti-reflection layer, the coating solution for forming an anti-reflection layer can be applied to the surface of a plastic substrate and cured, making it extremely easy to manufacture and highly efficient. The properties of the material are not impaired, and the impact resistance is not reduced.

The optical material of the present invention can be preferably used for eyeglass lenses, sunglasses, fashion glasses, ski or motorcycle goggles, safety glasses, binocular lenses, camera lenses, and other uses.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited thereto.

Example 1 Plastic substrate diethylene glycol bisallyl carbonate
35 parts by weight of diallylphthalate and 65 parts by weight of diallyl phthalate were copolymerized using isopropenyl peroxydicarbonate as a polymerization initiator to produce a plastic substrate molded into a plate shape with a thickness of 2 mm. The refractive index of this plastic substrate was 1.54.

Coating liquid for forming an antireflection layer: 60 parts by weight of fine magnesium fluoride powder with an average particle size of about 20 nm, and 46 parts by weight of epoxy resins ("EP4100", "ED503", and "EH261" manufactured by Asahi Denka Kogyo Co., Ltd.): 40 parts by weight (mixed at a ratio of 31:23) in ethyl alcohol and dispersed to form a coating liquid A for forming an antireflection layer with a solid content concentration of 5.5% by weight.
was prepared.

Antireflection layer The above plastic substrate is pretreated by immersing it in a 5% sodium hydroxide aqueous solution at 50°C for 10 minutes, and the above coating liquid A for forming an antireflection layer is applied to the surface of the plastic substrate. Apply by dipping method, then at 60℃ for 30 minutes and at 80℃.
An optical material was manufactured by heating and curing for 16 hours to form an antireflection layer with an average thickness of 300 nm and a refractive index of 1.40.

Evaluation The optical material obtained as described above had a reddish-purple reflected light color, and its total light transmittance was 96.4%. The total light transmittance of the plastic substrate before forming the antireflection layer was 91.8%, and it is therefore clear that the antireflection layer provides an excellent antireflection effect.

When this optical material was dyed by immersing it in a disperse dye solution containing a mixture of three colors: red, blue, and yellow at 90°C for 25 minutes, the dyeing process was completed until the total light transmittance decreased to 60%. It was done. In this optical material after dyeing, no peeling of the antireflection layer was observed, and no decrease in the antireflection effect was observed.

In addition, a total of 100 pieces of anti-reflection layer are formed by making cuts in the anti-reflection layer at 1 mm intervals vertically and horizontally, and adhesive tape is pasted on top of the pieces and then peeled off.At this time, the anti-reflection layer is peeled off along with the adhesive tape. The adhesion of the antireflection layer was tested by examining the presence or absence of layer pieces. As a result, the number of peeled antireflection layer pieces was zero.

In addition, steel wool was placed against the surface of the anti-reflection layer with a load of 500 g and rubbed back and forth 10 times. An abrasion resistance test was conducted in which the scratch resistance was evaluated in six grades: B', C, and C', and the result was B. Here, if the evaluation is A, A', B, or B', it is recognized that the material has scratch resistance that causes no practical problems.

Furthermore, the above optical material was subjected to an accelerated process of being irradiated with light from a "Sunshine Weather Meter" for 400 hours, and after that, the presence or absence of cracks was examined, and the same adhesion test and scratch resistance test as above were conducted. Ivy. As a result, there were no cracks, and the results of the adhesion test and scratch resistance test were the same as before the accelerated treatment, and no abnormalities were observed.

Example 2 Plastic base Commercially available diethylene glycol bisallyl carbonate eyeglass lens (outer diameter 70 mm, center thickness 1.8 mm,
A plastic material with a power of -0.25 diopters and a refractive index of 1.49 was prepared.

On the other hand, 35 parts by weight of γ-glycidoxypropyltrimethoxysilane and methyl alcohol silica sol
Tetraisopropyl bis(dioctyl phosphite) is added to 100 parts by weight of a mixture of 50 parts by weight, 10 parts by weight of 0.01N hydrochloric acid, and 5 parts by weight of maleic anhydride.
Titanate “Plen Act 41B” (manufactured by Ajinomoto Co., Inc.)
A coating liquid A for forming a surface layer was prepared by adding 20 parts by weight. Then, the surface of the plastic material was pretreated in the same manner as in Example 1, and the coating liquid A for forming a surface layer was applied by a dipping method,
After that, it is cured by heating at 60°C for 20 minutes and at 120°C for 3 hours to form a surface layer having properties as a hard coat layer with an average thickness of 2500 nm and a refractive index of 1.57.
A plastic substrate was obtained.

Antireflection Layer The coating liquid A for forming an antireflection layer prepared in Example 1 was applied to the plastic substrate on which the above surface layer was formed under the same conditions as in Example 1, but the dipping speed was adjusted, and the coating was cured. Then, an antireflection layer with an average thickness of 100 nm and a refractive index of 1.40 was formed to produce an optical material.

Evaluation The total light transmittance of the optical material obtained as described above was 96.8%. The total light transmittance of the plastic substrate having the surface layer before forming the antireflection layer was 90.3%, and it is therefore clear that the antireflection layer provides an excellent antireflection effect.

In addition, when this optical material was dyed with a disperse dye solution containing a mixture of three colors of red, blue, and yellow in the same manner as in Example 1, the dyeing was completed until the total light transmittance decreased to 74%. . In this optical material after dyeing, no peeling of the antireflection layer was observed, and no decrease in the antireflection effect was observed.

Further, the number of peeled antireflection layer pieces was 0 in the adhesion test conducted in the same manner as in Example 1, and the evaluation in the scratch resistance test was A'.

Furthermore, no cracks occurred in the optical material after the accelerated treatment performed in the same manner as in Example 1, and the results of the adhesion test and the scratch resistance test were the same as before the accelerated treatment, and no abnormalities were observed. Nakatsuta.

Furthermore, an impact resistance test using a falling ball method was conducted on the optical material having this antireflection layer. In other words, at a temperature of 20℃, the weight is 16.3 from a height of 1.27m.
The presence or absence of damage to the optical material was examined by allowing a steel ball of g to fall freely onto the optical material. As a result, no damage was observed to the optical material.

Incidentally, an optical material for comparison was manufactured by depositing magnesium fluoride on a plastic substrate having the above-mentioned surface layer by a conventional sputtering method to form an antireflection layer. However, this optical material
It completely shattered in the impact resistance test using the falling ball method.

From the above, it is clear that in the optical material of the present invention, the impact resistance of the plastic substrate is not impaired by the formation of the antireflection layer.

Example 3 Plastic Substrate A plastic substrate having the same refractive index of 1.54 as that used in Example 1 was prepared.

Coating liquid for forming an antireflection layer: 100 parts by weight of ethyl alcohol containing 5% by weight of fine magnesium fluoride powder with an average particle size of approximately 20 nm, 3 parts by weight of γ-glycidoxypropyltrimethoxysilane, and 15 parts by weight of methyltrimethoxysilane. 50 parts by weight of n-propyl alcohol and 3.7 parts by weight of ethyl cellosolve were added to a mixture of 10 parts by weight of 0.01N hydrochloric acid, and 0.5 parts by weight of maleic anhydride, and the mixture was stirred to form an antireflection layer. Coating liquid B was prepared.

Antireflection Layer The surface of the plastic substrate was pretreated in the same manner as in Example 1, and then the coating solution B for forming an antireflection layer was applied by a dipping method.
Cured by heating at 60℃ for 1 hour and 120℃ for 3 hours,
An optical material was manufactured by forming an antireflection layer with an average thickness of 250 nm and a refractive index of 1.41.

Evaluation The total light transmittance of the optical material obtained as described above was 96.4%. The total light transmittance of the plastic substrate before forming the antireflection layer is 91.8.
%, therefore, it is clear that an excellent antireflection effect can be obtained by the antireflection layer.

In addition, when this optical material was dyed with a dispersion dyeing solution containing a mixture of three colors, red, blue, and yellow, in the same manner as in Example 1, it was dyed until the total light transmittance decreased to 42%. . In this optical material after dyeing, no peeling of the antireflection layer was observed, and no decrease in the antireflection effect was observed.

Further, the number of peeled antireflection layer pieces was 0 in the adhesion test conducted in the same manner as in Example 1, and the evaluation in the scratch resistance test was B.

Furthermore, no cracks occurred in the optical material after the accelerated treatment performed in the same manner as in Example 1, and the results of the adhesion test and the scratch resistance test were the same as before the accelerated treatment, and no abnormalities were observed. Nakatsuta.

Example 4 Plastic base Commercially available diethylene glycol bisallyl carbonate eyeglass lens (outer diameter 70 mm, center thickness 2.0 mm,
A plastic material with a power of -0.25 diopters and a refractive index of 1.49 was prepared.

On the other hand, commercially available silicone hard coating agent "Sumimar G-35" (manufactured by Sumitomo Chemical Co., Ltd.) 100 c.c. was mixed with colloidal antimony pentoxide sol "ATM-130S" (manufactured by Nissan Chemical Co., Ltd.) with an average particle size of 60 nm. ) 15g, isopropyl alcohol 10g, and ethyl cellosolve 5g
A coating liquid B for forming a surface layer was prepared by adding the following.

The surface of the above plastic material was pretreated in the same manner as in Example 1, and then the above coating liquid B for forming a surface layer was applied by a dipping method and cured by heating to form a hard coat with an average thickness of 3600 nm and a refractive index of 1.57. A plastic substrate was obtained by forming a surface layer having the properties of a layer.

Antireflection Layer The plastic substrate on which the above surface layer was formed was coated and cured in the same manner as in Example 3 using coating solution B for forming an antireflection layer prepared in Example 3, so that the average thickness was 270 nm. An optical material was manufactured by forming an antireflection layer with a refractive index of 1.41.

Evaluation The total light transmittance of the optical material obtained as described above was 96.4%. The total light transmittance of the plastic substrate having the surface layer before forming the antireflection layer was 90.3%, and it is therefore clear that the antireflection layer provides an excellent antireflection effect.

In addition, when this optical material was dyed with a dispersion dyeing solution containing a mixture of three colors of red, blue, and yellow in the same manner as in Example 1, the dyeing was performed until the total light transmittance decreased to 48%. . In this optical material after dyeing, no peeling of the antireflection layer was observed, and no decrease in the antireflection effect was observed.

Further, the number of peeled antireflection layer pieces was 0 in the adhesion test conducted in the same manner as in Example 1, and the evaluation in the scratch resistance test was A'.

Furthermore, no cracks occurred in the optical material after the accelerated treatment performed in the same manner as in Example 1, and the results of the adhesion test and the scratch resistance test were the same as before the accelerated treatment, and no abnormalities were observed. Nakatsuta.

Furthermore, when the optical material having this antireflection layer was subjected to an impact resistance test using the falling ball method in the same manner as in Example 2, no damage was observed in the optical material.

Incidentally, an optical material for comparison was manufactured by depositing magnesium fluoride on a plastic substrate having the above-mentioned surface layer by a conventional sputtering method to form an antireflection layer. However, this optical material
It was completely damaged in an impact resistance test using the falling ball method.

From the above, it is clear that in the optical material of the present invention, the impact resistance of the plastic substrate is not impaired by the formation of the antireflection layer.

Example 5 Plastic substrate A plastic material with the same refractive index of 1.54 as that used in Example 1 was prepared, its surface was pretreated in the same manner as in Example 1, and the same material as that prepared in Example 2 was prepared. Coating liquid A for surface layer formation was applied by a dipping method and further heated and cured to form a surface layer having properties as a hard coat layer with an average thickness of 2500 nm and a refractive index of 1.57, thereby obtaining a plastic substrate.

Coating liquid for forming an antireflection layer Coating liquid C for forming an antireflection layer was prepared in the same manner as in Example 3, except that fine magnesium fluoride powder having an average particle size of about 40 nm was used.

Antireflection layer The surface of the plastic substrate was pretreated with plasma for 1 minute using a plasma reactor device "PR-501A" (manufactured by Yamato Scientific Co., Ltd.) at an oxygen gas flow rate of 150ml/min and an output of 500W, and then Coating liquid C for forming a prevention layer was applied by spin coating at a rotation speed of 3000 rpm for 1 minute, and then heated at 60°C for 1 hour and 120°C for 3 hours to cure, and the average thickness was
An optical material was manufactured by forming an antireflection layer with a thickness of 98 nm and a refractive index of 1.41.

Evaluation The total light transmittance of the optical material obtained as described above was 96.8%. The total light transmittance of the plastic substrate before forming the antireflection layer is 90.3.
%, therefore, it is clear that the antireflection layer provides an excellent antireflection effect.

Further, the number of peeled antireflection layer pieces was 0 in the adhesion test conducted in the same manner as in Example 1, and the evaluation in the scratch resistance test was A'.

Furthermore, no cracks occurred in the optical material after the accelerated treatment performed in the same manner as in Example 1, and the results of the adhesion test and the scratch resistance test were the same as before the accelerated treatment, and no abnormalities were observed. Nakatsuta.

Example 6 Plastic Substrate A plastic material having the same refractive index of 1.54 as that used in Example 1 was prepared.

On the other hand, 15 parts by weight of dipentaerythritol hexaacrylate, which is a polyfunctional acrylic resin, 15 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate, which is an aromatic acrylic resin, and 70 parts by weight of ethyl alcohol were mixed with light. A coating liquid C for forming a surface layer was prepared by adding 0.6 parts by weight of a polymerization initiator "Irgacure 184". Then, the surface of the plastic material was pretreated in the same manner as in Example 1, and then the coating liquid C for forming a surface layer was applied by the dipping method, and then pre-dried at 60°C for 10 minutes. The surface layer was cured by irradiating it with light from an ultraviolet irradiation device equipped with a high-pressure mercury lamp for 10 seconds at a position 15 cm downward to form a surface layer with properties as a hard coat layer with an average thickness of 3000 nm and a refractive index of 1.56. A plastic substrate was obtained.

Antireflection layer The plastic substrate on which the above surface layer was formed was coated and cured in the same manner as in Example 5 using the coating liquid C for forming an antireflection layer prepared in Example 5, so that the average thickness was 98 nm. An optical material was manufactured by forming an antireflection layer with a refractive index of 1.41.

Evaluation The total light transmittance of the optical material obtained as described above was 96.8%. The total light transmittance of the plastic substrate having the surface layer before forming the antireflection layer was 90.7%, and it is therefore clear that the antireflection layer provides an excellent antireflection effect.

Further, the number of peeled antireflection layer pieces was 0 in the adhesion test conducted in the same manner as in Example 1, and the evaluation in the scratch resistance test was A'.

Furthermore, no cracks occurred in the optical material after the accelerated treatment performed in the same manner as in Example 1, and the results of the adhesion test and the scratch resistance test were the same as before the accelerated treatment, and no abnormalities were observed. Nakatsuta.

Furthermore, when the optical material having this antireflection layer was subjected to an impact resistance test using the falling ball method in the same manner as in Example 2, no damage was observed in the optical material.

Incidentally, an optical material for comparison was manufactured by depositing magnesium fluoride on a plastic substrate having the above-mentioned surface layer by a conventional sputtering method to form an antireflection layer. However, this optical material
It completely shattered in the impact resistance test using the falling ball method.

From the above, it is clear that in the optical material of the present invention, the impact resistance of the plastic substrate is not impaired by the formation of the antireflection layer.

Example 7 Plastic Substrate A plastic substrate having the same refractive index of 1.54 as that used in Example 1 was prepared.

Coating liquid for forming an antireflection layer An antireflection layer was formed in the same manner as in the coating liquid B for forming an antireflection layer in Example 3, except that 7 parts by weight of diacetone alcohol was used instead of 50 parts by weight of n-propyl alcohol. Coating liquid D was prepared.

Antireflection layer The surface of the plastic substrate was pretreated with plasma for 1 minute using a plasma reactor device "PR-501A" (manufactured by Yamato Scientific Co., Ltd.) at an oxygen gas flow rate of 150ml/min and an output of 500W, and then Coating liquid D for forming an antireflection layer is applied by a dipping method, and then heated at 60°C for 30 minutes and at 120°C for 3 hours to cure, forming an antireflection layer with an average thickness of 500 nm and a refractive index of 1.41 to form an optical material. was manufactured.

Evaluation The total light transmittance of the optical material obtained as described above was 96.0%. The total light transmittance of the plastic substrate before forming the antireflection layer is 91.5.
%, therefore, it is clear that the antireflection layer provides an excellent antireflection effect.

In addition, when this optical material was dyed with a disperse dye solution containing a mixture of three colors, red, blue, and yellow, in the same manner as in Example 1, the dyeing was completed until the total light transmittance decreased to 47%. . In this optical material after dyeing, no peeling of the antireflection layer was observed, and no decrease in the antireflection effect was observed.

Further, the number of peeled antireflection layer pieces was 0 in the adhesion test conducted in the same manner as in Example 1, and the evaluation in the scratch resistance test was B.

Furthermore, no cracks occurred in the optical material after the accelerated treatment performed in the same manner as in Example 1, and the results of the adhesion test and impact resistance test were the same as before the accelerated treatment, and no abnormalities were observed. Nakatsuta.

Furthermore, when the optical material having this antireflection layer was subjected to an impact resistance test using the falling ball method in the same manner as in Example 2, no damage was observed in the optical material.

From the above, it is clear that in the optical material of the present invention, the impact resistance of the plastic substrate is not impaired by the formation of the antireflection layer.

Example 8 Plastic substrate 25 parts by weight of 1-acryloxy-2,4,6-tribromobenzene and 2,2-bis(4-methacryloxyethoxy-3,5-dibromophenyl)
A plastic substrate molded into a plate having a thickness of 2 mm was produced by copolymerizing 50 parts by weight of propane and 15 parts by weight of styrene. The refractive index of this plastic substrate was 1.60.

Coating liquid for forming an antireflection layer In the coating liquid B for forming an antireflection layer in Example 3, the content ratio of fine magnesium fluoride powder was
Coating for forming an antireflection layer was carried out in the same manner as in Example 3, except that the concentration was changed to 15% by weight, and the amounts of n-propyl alcohol and ethyl cellosolve were adjusted to make the total solids concentration 25% by weight. Solution E was prepared.

Antireflection layer The above plastic substrate is pretreated by immersing it in an aqueous sodium hydroxide solution with a concentration of 20% at 80°C for 30 minutes, and the above coating liquid E for forming an antireflection layer is applied to the surface of the plastic substrate by a dipping method. The average thickness was 2800 nm, the refractive index was
An optical material was manufactured by forming an antireflection layer of 1.40.

Evaluation The total light transmittance of the optical material obtained as described above was 96.0%. The total light transmittance of the plastic substrate before forming the antireflection layer is 88.6.
%, therefore, it is clear that the antireflection layer provides an excellent antireflection effect.

In addition, when this optical material was dyed with a disperse dye solution containing a mixture of three colors of red, blue, and yellow in the same manner as in Example 1, the dyeing was completed until the total light transmittance decreased to 72%. . In this optical material after dyeing, no peeling of the antireflection layer was observed, and no decrease in the antireflection effect was observed.

Further, the number of peeled antireflection layer pieces was 0 in the adhesion test conducted in the same manner as in Example 1, and the evaluation in the scratch resistance test was A'.

Furthermore, no cracks occurred in the optical material after the accelerated treatment performed in the same manner as in Example 1, and the results of the adhesion test and the scratch resistance test were the same as before the accelerated treatment, and no abnormalities were observed. Nakatsuta.

Furthermore, when the optical material having this antireflection layer was subjected to an impact resistance test using the falling ball method in the same manner as in Example 2, no damage was observed in the optical material.

From the above, it is clear that in the optical material of the present invention, the impact resistance of the plastic substrate is not impaired by the formation of the antireflection layer.

Claims (1)

[Claims] 1. A transparent plastic substrate with a refractive index of 1.48 or more, and an inorganic fine powder made of magnesium fluoride with an average particle size of 0.3 to 200 nm, which is formed to cover the surface of the plastic substrate, in a binder. 1. An optical material having an antireflection layer having a thickness of 50 to 5000 nm and having a refractive index lower by 0.02 or more than the plastic substrate. 2 The plastic substrate has a refractive index on its surface.
The optical material having an antireflection layer according to claim 1, having a surface layer of 1.48 or more. 3. Applying a coating liquid for forming an antireflection layer containing a binder material and an inorganic fine powder of magnesium fluoride with an average particle size of 0.3 to 200 nm on the surface of a transparent plastic substrate with a refractive index of 1.48 or more, An optical material having an antireflection layer, characterized in that the inorganic fine powder is dispersed in a binder to form an antireflection layer with a thickness of 50 to 5000 nm and having a refractive index lower than that of the plastic substrate by 0.02 or more. Production method.