JPH081481B2 - Plastic mirror lenses - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention improves the scratch resistance of a surface, and The present invention relates to a plastic mirror-coated lens with reduced side reflection.

[Conventional technology]

Various types of sunglasses for cashiers are on the market, but recently, particularly overseas, the number of sunglasses in which a glass surface is mirror-coated to give a metallic luster is increasing. However, since these mirror-coated sunglasses are made of glass as a base material, they are heavy and easily broken, and therefore are not suitable for active activities at the time of registering. In order to solve such a problem, it is conceivable that the base material is made organic, and some mirror-coated lenses made of the organic base material are commercially available. However, such a mirror-coated lens has a problem in terms of heat resistance of the material,
Further, since the adhesion to the metal is not sufficient, the scratch resistance of the lens is extremely poor.

However, with the recent progress of the vacuum evaporation method, a method of improving the adhesion of metal to a plastic material has been gradually put into practical use. Examples of applying those techniques to plastic mirror-coated sunglasses are disclosed in JP-A-55-46713, JP-A-55-46714, JP-A-55-46715, and JP-A-55-46716. It is disclosed. In these publications, C is a metal that can be used as a mirror coat.
u, Au, Al, Ti, Ni, Cr, Co, Ag, etc. are coated on various plastics by the high frequency ion plating method to improve the adhesion.

[Problems to be solved by the invention]

However, in the actual use of eyeglass lenses and sunglasses,
It is not enough to improve the adhesiveness of the coating film alone, and particularly in the case of plastic lenses, it is an important issue to sufficiently provide the surface with scratch-resistant resin. Further, merely coating the plastic lens with a metal causes strong reflection on both surfaces of the coating film, which is disadvantageous in use as a mirror-coated lens and reduces the commercial value.

[Means for solving problems]

In order to solve the above-mentioned problems of the prior art, the present inventors focused on a method of applying an organic hard coat film having good scratch resistance as a base layer on the plastic surface, and applying a mirror coat on it, research Layered. As a result, the general formula with colloidal silica (In the formula, R ₁ is an alkyl group having 1 to 6 carbon atoms, and R ₂ is 1 carbon atom.
When an organosilicon compound having an alkyl group of 6 to 6) is used, the coating film has sufficient flexibility, heat resistance and weather resistance even if the organosilicon compound is in a relatively small amount, and as a result, a hardness imparting component. It is possible to keep the ratio of colloidal silica, which is a high value, and to form a multilayer structure of metal oxide and metal on this organic hard coat film to reduce the reflection on the opposite surface while keeping the reflection on the coated surface. I found what I could do.

The present invention has been achieved based on such knowledge, and colloidal silica and a general formula are formed on the surface of a plastic lens. (In the formula, R ₁ is an alkyl group having 1 to 6 carbon atoms, and R ₂ is 1 carbon atom.
To an alkylene group of 6) as a main component, and an underlayer formed by curing with a curing agent is applied, and a layer composed of a metal oxide and a metal are formed thereon by a method such as vacuum deposition. Alternatively, the mirror-coated lens made of plastic is provided with a mirror-coated layer having a multilayer structure including a layer made of a metal oxide.

That is, the lens of the present invention has 75-90 mol% on any surface of the plastic lens.
(SiO ₂ solid content conversion value) colloidal silica and general formula (In the formula, R ₁ is an alkyl group having 1 to 6 carbon atoms, R ₂ is 1 carbon atom
-5 is an alkylene group of -6), and an underlayer formed by curing with a curing agent is provided with 25-5 mol% of an organosilicon compound as a main component, and the following vapor deposition is performed on this underlayer by a vacuum vapor deposition method. A mirror coat lens made of plastic, which is provided with a multi-layered mirror coat film: a first layer; any one or more kinds of metal oxides of SiO, TiO ₂ and ZrO ₂ and having a thickness of λ / 4 Second layer; metal consisting of Cr or Ti, or lower oxide of these metals, having a film thickness of λ of 450 to 550 nm and transmittance of 60 to 50% Third layer: TiO ₂ , ZrO ₂ , Ti ₂ O _{3 and} at least one kind of metal oxide having a film thickness of λ / 4 fourth layer; the same metal as those of the second layer or a metal oxide thereof, and having a transmittance of 20 at λ of 450 to 550 nm. -10% film thickness 5th layer; SiO ₂ film thickness is λ / 4 6th layer; SiO, TiO, TiO ₂ , Ti ₂ O ₃ , ZrO ₂ Any one or more metal oxide film thickness Is λ / 4 Is.

In the present invention, the plastic lens is a diethylene glycol bisallyl carbonate polymer (CR-3
9), polymethylmethacrylate (PMMA), polycarbonate, polystyrene and the like. Further, the plastic lens can be dyed as desired before the coating process in order to adjust the transmission color of the lens.

The colloidal silica and the organosilicon compound represented by the general formula are such that the amount of colloidal silica is 75 to 90 mol% (SiO ₂ solid content conversion value) and the amount of organosilicon compound is 25 to 50 mol% based on the total amount of the organosilicon compound. The amount of the curing agent is an amount sufficient to cure the colloidal silica and the hydrolyzate of the organosilicon compound.

As the organosilicon compound having the above general formula used in the present invention, R _{1 in} the formula is a methyl group, an ethyl group,
Preferred is a propyl group or a butyl group, and R ₂ is a methylene group, an ethylene group, a propylene group or a butylene group.

Further, in the present invention, as the colloidal silica, in order to prevent excess water from being left after the hydrolysis of the organosilicon compound, water-dispersed colloidal silica having a high concentration (SiO ₂ solid content of 40 to 50%) is used as much as possible. Is preferred. The particle size is preferably about 5 mμ to 30 mμ. Sunotetsukusu -40 Specific examples of colloidal silica (Nissan Chemical, SiO ₂ 40% concentration, water-dispersible silica), Cataloid -S
l-40 (Catalysts & Chemicals Industries, SiO ₂ 40% strength, aqueous dispersion of silica), Cataloid -sl-50 (Catalysts & Chemicals Industries, 50% strength,
Water-dispersed silica) and the like.

Further, alcohol-dispersed colloidal silica can be used instead of water-dispersed colloidal silica, but when the obtained composition is applied and cured, there is a problem that cloudiness and small gel-like bumps are likely to occur. Dispersed colloidal silica is preferred.

Examples of the curing agent used in the present invention include imidazole derivatives, but acetylacetone metal salt is particularly effective. The amount of addition is sufficient to cure the colloidal silica and the hydrolyzate of the organosilicon compound, for example, 1 to 10 g per 1 mol of the total of the hydrolyzate of colloidal silica (SiO ₂ conversion) and the organosilicon compound. Is.

Examples of the solvent used in the coating composition include lower alcohols, esters, ethers and ketones, with isopropyl alcohol, butanol and methyl cellosolve being particularly preferred.

A silicone-based surfactant may be added to the composition for the underlayer for the purpose of improving the smoothness of the coating film.
Furthermore, for the purpose of improving weather resistance or preventing deterioration of the coating film,
It is also possible to add an ultraviolet absorber, an antioxidant and the like.

Various additives may be added for the purpose of improving practicality such as adhesion to a substrate (plastic lens) and improvement of physical properties.

Further, the addition of sodium acetate, which is generally used for stabilizing the pH of the coating liquid and also as a catalyst, is not preferable in the present invention. The reason is that sodium acetate tends to precipitate toward the film surface after coating and curing the coating composition, which adversely affects the film formation of the vapor deposition material,
Further, even if the lens surface is cleaned by hand-wiping or washing before vapor deposition, it is deposited in vacuum or by heating, which also has an adverse effect.

The mirror coat film provided on the base layer has a multilayer structure including a layer made of a metal oxide and a layer made of a metal or a metal oxide. Here, the metal oxide is silicon monoxide (Si
O), silicon dioxide (SiO ₂ ), titanium dioxide (TiO ₂ ), zirconium dioxide (ZrO ₂ ), titanium trioxide (Ti ₂ O ₃ ),
Examples thereof include titanium monoxide (TiO) and a lower oxide of Cr, and examples of the metal include Cr or Tr.
As a result of examining various metal oxides and metals capable of more sufficiently maintaining the adhesion and scratch resistance of the mirror coat film, when forming the mirror coat film by the vacuum deposition method, SiO, SiO ₂ , ZrO
₂ , it has been found that the combination of the metal oxide of TiO _{2 and} the metal of Cr or Ti is effective.

Further, in the present invention, it is preferable that the number of the mirror coat layers having a multi-layer structure including the underlayer be seven. in this case,
When the underlayer is the first layer, the second layer is a thin film made of one or more metal oxides of SiO, TiO _{2 and} ZrO ₂ , and the third layer is
A thin film made of a metal of Cr or Ti, or a lower oxide of these metals, a fourth layer is a thin film made of one or more kinds of metal oxides of TiO ₂ , ZrO ₂ or Ti ₂ O ₃ , and a fifth layer is A film made of the same metal or metal oxide as the third layer and having a thickness about twice that of the third layer, a sixth layer is a thin film made of SiO ₂ , and a seventh layer is
When each layer of a thin film made of one or more kinds of metal oxides of SiO, TiO ₂ , ZrO ₂ , Ti ₂ O ₃ or TiO is sequentially laminated, a plastic mirror-coated lens having such a multilayered mirror-coated layer is formed. Can be sufficiently used as a spectacle lens, and reflection on the opposite surface of the mirror coat film can be reduced. The second layer is particularly SiO, the third layer is especially Cr or its lower oxide, and the fourth layer is especially Zr.
O ₂ and Cr or its lower oxide are particularly effective as the fifth layer, SiO ₂ is especially effective as the sixth layer, and SiO is especially effective as the seventh layer.

The second SiO layer has an optical film thickness of λ / 4 (λ: 450 to 550 nm),
The third Cr layer has a transmittance (λ) of 60 to 50%, the fourth ZrO ₂ layer has an optical thickness λ / 4, and the fifth Cr layer has a transmittance (λ). If the film thickness is 20 to 10%, the sixth SiO ₂ layer has an optical thickness λ / 4, and the seventh SiO layer has an optical thickness λ / 4, the scratch resistance of the mirror coat film and the mirror The effect of reducing reflection on the surface opposite to the coating film surface is great.

Next, an example of the coating method of the plastic lens using the composition for the underlayer will be described.

First, an inorganic acid such as hydrochloric acid or an organic acid such as acetic acid is added to colloidal silica to make the colloidal silica acidic (for example,
The pH is set to 2 to 6), then the liquid temperature is set to 30 to 50 ° C., and the organosilicon compound having the above general formula is added dropwise and stirred to hydrolyze the organosilicon compound.

The above-mentioned solvent, for example, isopropyl alcohol, butanol, methyl cellosolve, etc., is added to the hydrolyzed mixed solution, and a predetermined amount of a curing agent is further added.

The composition thus obtained does not cause gelation and does not increase in viscosity, although the colloidal silica content is 75 to 95 mol%.

The composition obtained above is then applied onto the plastic lens by a commonly used dipping and pulling method (a dipping method), a spin coater method, a roll coater method, a spray method or the like.

Curing of the composition applied on the plastic lens
Mainly performed by heat treatment, the heating temperature can be in a wide range, preferably 40 ℃ ~
150 ° C, particularly preferably 80 ° C to 120 ° C. The heating time of 1 to 4 hours or more gives good results.

The coating film obtained by the heat-curing treatment has excellent wear resistance (hardness) and also flexibility (flexibility), heat resistance, and chemical resistance (alkali).

Before applying the coating composition of the present invention, it is preferable to pretreat the plastic lens by alkali treatment, plasma treatment, ultraviolet irradiation treatment or the like. The opposite side of the lens with the mirror coat film By applying a multilayer anti-reflection coating of SiO, Al ₂ O ₃ , SiO ₂ , ZrO ₂ , TiO ₂ etc. to the The reflection of can be further reduced.

〔The invention's effect〕

According to the present invention, the surface hardness (wear resistance, scratch resistance) of the coating film can be kept high, and the mirror coat lens using this coating film as the underlying layer is the biggest drawback of the conventional plastic mirror coat. It is possible to manufacture a lens that overcomes the susceptibility to scratches and has the antireflection effect required for a spectacle lens.

Example of Invention

Examples of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto. In the examples, [part] is part by weight.

Example 1 Colloidal silica (Snowtex-40, Nissan Chemical)
A solution prepared by adding 2.0 parts of 0.5N hydrochloric acid and 20 parts of acetic acid to 240 parts is prepared at 35 ° C.
With stirring, 94.4 parts of γ-glycidoxypropyltrimethoxysilane was added dropwise, and the mixture was stirred at room temperature for 8 hours and left at room temperature for 16 hours. 80 parts of methyl cellosolve, 120 parts of isopropyl alcohol, 40 parts of butyl alcohol, 16 parts of aluminum acetylacetone,
A silicone-based surfactant (0.2 parts) and an ultraviolet absorber (0.1 parts) were added, and the mixture was stirred for 8 hours and then aged at room temperature for 24 hours to obtain a coating composition.

The ratio of silicon compound is 80 mol of colloidal silica.
% (SiO ₂ solid content) and 20 mole% of γ-glycidoxypropyltrimethoxysilane.

This coating composition was applied to the plastic lens (CR-39) 1 shown in FIG. 1 and cured by heating to about 3 μm.
A thick organic hard coat film 2 was provided. Then, SiO (λ / 4 λ: 450 to 5 is formed on the organic hard coat film 2 by a vacuum deposition method.
50 nm) layer 3, Cr (λ) layer 4 having a film thickness of 60% in transmittance, ZrO ₂
(Λ / 4) layer 5, Cr (λ) layer 6 having a film thickness of 20% in transmittance, Ci
An O ₂ (λ / 4) layer 7 and a SiO (λ / 4) layer 8 were formed.

Of the mirror coat film formed as described above The spectral reflectances of are shown in FIGS. 2 (a) and 2 (b), respectively. In FIG. 2, A is the spectral reflectance when the hard coat film is treated and B is applied with the mirror coat film. From Figure 2 The reflection on the coated side of the surface is strong enough throughout the visible range, nevertheless Reflection of the coating film to the surface side is around 0.7% (lens It can be seen that the film has a sufficiently good antireflection function as well as residual reflection (excluding 4% of surface reflection).

Comparative Example 1 Colloidal silica (Snowtex-40, Nissan Chemical)
To 90 parts, 2.0 parts of 0.5N hydrochloric acid, 20 parts of acetic acid, and 90 parts of water were added, and 190 parts of methyltrimethoxysilane was added dropwise with stirring. After that, the mixture was stirred at room temperature for 8 hours and left at room temperature for 16 hours. Then, a coating composition was obtained in the same manner as in Example 1.

The ratio of silicon compound is 30 moles of colloidal silica.
% (Solid content) and 70 mole% of methyltrimethoxysilane. Application of this coating composition to a CR-39 lens, heat curing, and treatment of the mirror coat film were the same as in Example 1.

Comparative Example 2 Colloidal silica (Snowtex-40, Nissan Chemical)
To 150 parts, add 2.0 parts of 0.5N hydrochloric acid, 20 parts of acetic acid, 54 parts of water,
After 136 parts of methyltrimethoxysilane was added dropwise with stirring, the mixture was stirred at room temperature for 8 hours and allowed to stand at room temperature for 16 hours, and a coating composition was obtained in the same manner as in Example 1 below.

The ratio of silicon compound is 50 moles of colloidal silica.
% (Solid content) and 50 mole% of methyltrimethoxysilane. Application of this coating composition to a CR-39 lens, heat curing, and treatment of the mirror coat film were the same as in Example 1.

Proportional 3 Colloidal Silica (Snowtex-40, Nissan Chemical)
After adding 2.0 parts of 0.5N hydrochloric acid, 20 parts of acetic acid and 36 parts of water to 180 parts, 110 parts of methyltrimethoxysilane was added dropwise with stirring,
After stirring at room temperature for 8 hours and leaving at room temperature for 16 hours, a coating composition was obtained in the same manner as in Example 1 below.

The ratio of silicon compound is 60mole of colloidal silica.
% (Solid content) and 40 mole% of methyltrimethoxysilane. Application of this coating composition to a CR-39 lens, heat curing, and treatment of the mirror coat film were the same as in Example 1.

Comparative Example 4 472 parts of γ-glycidoxypropylmethoxysilane, water 1
00 parts and 0.1 part of 0.1N hydrochloric acid were added, and the mixture was stirred for 8 hours and allowed to stand at room temperature for 16 hours. Then, a coating composition was obtained in the same manner as in Example 1. Application of this composition to CR-39, heat curing, and treatment of the mirror coat film were the same as in Example 1.

Comparative Example 5 A CR-39 lens was coated with a SiO ₂ film to a thickness of about 2 μm by a vacuum deposition method to form a hard coat film. The deposition conditions were a vacuum degree of 2 × 10 ⁻⁵ nmHg and a substrate temperature of 80 ° C. The treatment of the mirror coat film on this lens is the same as that in the first embodiment.

Test example The test is to apply the coating composition to the CR-39 lens,
A hard coat lens formed by heating and curing to form a coating film, a hard coat lens of SiO ₂ film having a film thickness of 2 μm coated by vacuum vapor deposition, and a mirror coat layer by vacuum vapor deposition on the cured coating film of the hard coat lens. I made a comparison with the one given. As shown in FIG. 1, this mirror coat film is made of metal oxides SiO, ZrO ₂ , SiO ₂ and metal Cr as shown in FIG. 1 in order to reduce the reflected light from the coat film to the opposite surface. It has a laminated structure. The mirror coat film was obtained by simultaneously treating all the hard coat lenses of Comparative Example and Example 1.

 The outline of various test methods will be described below.

(A) Abrasion resistance (scratch resistance) The surface is loaded with 1000 g of # 0000 steel wool.
After rubbing 500 times (round trip), the following judgment was made.

A: Almost no scratches.

B: A little scratched.

C: Many scratches.

D: Film peeling occurs.

This test was carried out both on a plastic lens having a hard coat film and on a plastic lens having a hard coat film and a mirror coat film.

(B) Adhesiveness 10 × 10 pieces of 1 mm square gougin were formed, and a peeling test with a cellophane adhesive tape was performed 3 times to examine the number of gougin eyes left.

The cellophane tape used was that of Nichiban JIS-Z-1522.

(C) Appearance The transparency, the colored state, the surface state and the like were examined by visual observation.

(D) Heat resistance and hot water resistance (a) A plastic lens coated with the coating composition and cured was placed in a constant temperature oven at 150 ° C., and it was examined whether or not cracks were formed in the coating film.

(B) It was immersed in boiling water for 1 hour and examined for changes due to appearance.

(E) Weather resistance Xenon long life weather meter WEI-25AX
(Suga tester), accelerated exposure was carried out for 500 hours to examine whether the coating film was yellowed or deteriorated.

(F) Chemical resistance The coating film was immersed in the following solution for 1 hour at room temperature, and the change in the coating film was examined.

1. 10% NaOH solution 2. 10% HCl solution 3. Acetone solution 4. Methanol solution The test results for Example 1 and Comparative Examples 1 to 5 are shown in the table below.

As is clear from the above table, Example 1 has an appearance, adhesion,
While it provides a coating film with excellent heat resistance, hot water resistance, weather resistance, chemical resistance, and abrasion resistance,
Comparative Examples 1-5 were inferior in at least one of the above properties. Further, in Example 1, the improvement of abrasion resistance was particularly remarkable in the plastic lens having the hard coat film (underlayer) and the mirror coat film.

Even in the component systems of colloidal silica and methyltrimethoxysilane shown in Comparative Examples 1 to 3, as the proportion of colloidal silica (mole%) increased, the hardness of the composite film as the underlayer of the mirror coat film was Although it can be seen that cracking occurs when the proportion of colloidal silica exceeds 60 mole%. Therefore, more than this,
The proportion of colloidal silica cannot be increased, and the hardness of the composite film cannot be improved beyond a certain level.

In Comparative Example 4, the hardness of the hard coat film alone is high, but when the mirror coat film is provided on the hard coat film, the effect of the hard coat layer as the underlying layer is small and the abrasion resistance of the mirror coat is lowered. Further, in Comparative Example 5, the wear resistance is lower than that in Example 1.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of a ⊥ face of a lens showing an embodiment of the present invention, and FIG. 2 (a) is a reflectance characteristic diagram on the ⊥ face side of a mirror-coated lens obtained in Embodiment 1. FIG. 2B shows the mirror-coated lens obtained in Example 1. It is a reflectance characteristic view of the surface side. 1 ... CR-39 (plastic base material) 2 ... organic hard coat film, 3 ... SiO layer 4 ... Cr layer, 5 ... ZrO ₂ layer 6 ... Cr layer, 7 ... SiO ₂ layer 8 ... … SiO layer

Claims (2)

[Claims] 1. A plastic lens having 75
-90 mol% (SiO ₂ solid content equivalent) colloidal silica and general formula (In the formula, R ₁ is an alkyl group having 1 to 6 carbon atoms, R ₂ is 1 carbon atom
-5 is an alkylene group of -6), and an underlayer formed by curing with a curing agent is applied as a main component with 25-5 mol% of an organosilicon compound, and the following vapor deposition is performed on this underlayer by a vacuum vapor deposition method. A mirror coat lens made of plastic, which is provided with a multi-layered mirror coat film: a first layer; any one or more kinds of metal oxides of SiO, TiO ₂ and ZrO ₂ and having a thickness of λ / 4 Second layer; metal consisting of Cr or Ti, or lower oxide of these metals, having a film thickness of λ of 450 to 550 nm and transmittance of 60 to 50% Third layer: TiO ₂ , ZrO ₂ , Ti ₂ O _{3 and} at least one kind of metal oxide having a film thickness of λ / 4 fourth layer; the same metal as those of the second layer or a metal oxide thereof, and having a transmittance of 20 at λ of 450 to 550 nm. -10% film thickness 5th layer; SiO ₂ film thickness is λ / 4 6th layer; SiO, TiO, TiO ₂ , Ti ₂ O ₃ , ZrO ₂ Any one or more metal oxide film thickness Is λ / 4 2. The plastic mirror-coated lens according to claim 1, wherein a multilayer antireflection film is provided on the opposite surface of the plastic lens provided with the mirror-coated film.