JPH0455588B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention has excellent scratch resistance, abrasion resistance, impact resistance,
Chemical resistance, flexibility, heat resistance, hot water resistance, light resistance,
The present invention relates to an antireflection article that has excellent weather resistance, stainability, and antireflection properties and is suitable for optical applications such as eyeglass lenses, camera lenses, and CRT filters, and a method for manufacturing the same. [Prior Art] Plastic molded products, especially molded products such as plastic lenses, have been in great demand in recent years because they have extremely excellent impact resistance and transparency, are lightweight, and can be easily dyed. is increasing. However, plastic has the disadvantage that its surface hardness is lower than that of inorganic glass and it is easily scratched. Furthermore, when viewing objects through a transparent substrate such as an inorganic glass article or a transparent plastic molded article, the reflected light is strong and it is troublesome for the reflected image to be clear. For example, in eyeglass lenses, reflected images called ghosts and flares can occur. This can cause eye discomfort. Therefore, in order to prevent reflection, a method has heretofore been used in which a film of a material having a refractive index different from that of the base material is formed on the base material by vacuum evaporation or the like. In this case, it is known that the selection of the thickness of the material coating the base material is important in order to have a high antireflection effect (Optical Technology Contact Vol. 9).
No. 8, 17-23, (1971)). For example, in a single-layer film, if a material with a lower refractive index than the base material is selected so that the optical film thickness is 1/4 or an odd multiple of the wavelength of light, minimum reflectance, that is, maximum transmittance can be obtained. It has been known. The optical film thickness here is given by the product of the refractive index of the film forming material and the film thickness of the film. Further, JP-A-52-16586 proposes providing an organopolysiloxane resin layer on a plastic molded product, and providing a metal and/or inorganic ceramic material layer thereon. [Problems to be Solved by the Invention] However, coating a film made of an inorganic oxide on a film made of an organopolysiloxane resin does not provide a sufficiently strong adhesion, resulting in peeling of the film and surface problems. It has many drawbacks, such as a decrease in hardness and the scratches that occur are thick and deep, resulting in poor practical durability. [Means for Solving the Problems] The present inventors have conducted intensive studies to solve the problems of the prior art, and as a result, have the following configuration. That is, the present invention provides an antireflection article characterized by having a two-layer structure in which the following coatings A and B are laminated in this order on the surface of a transparent base material. A has a refractive index of 1.47 to 1.65, Film thickness is 100~
20,000 nm, and a coating made of an organic polymer containing 5 to 80% by weight of inorganic oxide fine particles as a coating component. B: A film made of SiO ₂ . Here, the transparent base material is a transparent base material whose haze value calculated by the following formula is 80% or less, and
If necessary, this may include those colored with dyes or the like, and those colored in patterns. In addition, transparent substrates coated with a coating material to impart scratch resistance, etc., are also included in the transparent substrates of the present invention if the haze value determined by the following formula is 80% or less. be able to. Haze value (percentage) = Diffuse light transmittance/Total light transmittance x 100 In order to more effectively exhibit the effect of reducing light reflectance and improving light transmittance as intended by the present invention, it is necessary to make the material as transparent as possible. Preferably. Furthermore, in the case where the reduction in light reflectance in the present invention is sufficient on only one side of the base material, even if the opposite side is covered with an opaque material,
It can be used as a transparent substrate as referred to in the present invention. In this case, the haze value must be defined without the opaque material on the opposite side. Examples of such transparent substrates include molded articles such as glass and plastic articles, sheets, and films. The present invention first applies the above-mentioned A to the surface of these transparent substrates.
The A coating has a refractive index of 1.47 to 1.65, and a film thickness of 100 to 1.65.
It needs to be 20000nm. That is,
If the refractive index is less than 1.47, the antireflection effect will be poor, and if it is less than 1.45, reflection will increase. On the other hand, if the refractive index exceeds 1.65, a difference in refractive index with the transparent base material is likely to occur, reflection interference fringes will be observed, and the commercial value will be low. Further, if the film thickness is less than 100 nm, the improvement in surface hardness, heat resistance, chemical resistance, etc., which is the purpose of providing the A coating, cannot be expected. Moreover, if it exceeds 20,000 nm, a decrease in impact resistance etc. is observed, which is not preferable. As a component constituting the A film having these characteristics, inorganic oxide fine particles are contained in the film in an amount of 5 to 80% by weight.
It is necessary to include. i.e. 5% by weight
If it is less than 80% by weight, it will not be possible to obtain a sufficiently strong adhesive strength with the SiO ₂ coating, and if it exceeds 80% by weight, there will be problems such as poor adhesion to the transparent substrate, cracks in the A coating, and decreased impact resistance. In addition, the inorganic oxide fine particles used here are not limited as long as they do not impair transparency in the coating state, but from the viewpoint of workability and transparency, particularly preferred examples include colloidal particles. Examples include sol dispersed in More specific examples include silica sol, titania sol, zirconia sol, antimony oxide sol, and alumina sol. Among these, antimony oxide sol and titania sol are particularly preferred from the viewpoint of surface hardness, durability against perspiration, and improvement in gloss. The inorganic oxide fine particles have an average particle diameter of 1 to
A particle size of 200 mμ is usually used, but preferably a particle size of 5 to 100 mμ is used. If the average particle size exceeds 200 mμ, the resulting film will have reduced transparency and become highly cloudy, making it difficult to thicken the film. Further, there is no problem in adding various surfactants and amines to improve the dispersibility of the fine particles. Furthermore, there is no problem in using two or more types of inorganic oxide fine particles in combination. Coating A in the present invention contains a polymer made of an organic substance in addition to the above-mentioned inorganic oxide fine particles, and the organic polymer has transparency and uniformly disperses the inorganic oxide fine particles. Although there are no particular limitations on the resin as long as it can be used to form a transparent film, heat-effect resins are preferably used from the viewpoint of the hardness and chemical resistance of the film. Preferred specific examples of these thermosetting resins include monomers, oligomers, or prepolymers having polyfunctional acrylic groups, melamine resins, epoxy resins, and polyurethane resins. Polyurethane resins include aliphatic, alicyclic or aromatic isocyanates, and urethane-forming compositions comprising these and polyols. Furthermore, it also includes various modified resins that have been made capable of radical curing by introducing double bonds into the above-mentioned compounds.
Furthermore, organopolysiloxane compounds obtained from aeration-substituted silicon compounds are also preferably used. The above silicon-based compound is a compound represented by the general formula R ¹ _a R ² _b SiX _4-(a+b) or a hydrolysis product thereof. Here, R ¹ and R ² are each an alkyl group, an alkenyl group, an aryl group, or a hydrocarbon group having a halogen group, an epoxy group, a glycidoxy group, an amino group, a mercapto group, a methacryloxy group or a cyano group, and are of the same type. They may be of different species. X is a hydrolyzable substituent selected from alkoxy, alkoxyalkoxy, phenoxy to acetoxy groups, a and b are each 0, 1 or 2, and a+b is 1 or 2. In the case where an epoxy group or a glycidoxy group is contained in the above, the coating can be easily dyed or colored with a disperse dye or the like, resulting in a high added value. The above compositions are usually diluted in volatile solvents and applied as liquid compositions. The solvent used as a solvent is not particularly limited, but when used, it is required that it does not impair the surface properties of the object to be coated, and in addition, the stability of the composition, wettability to the substrate, volatility, etc. The decision should also be taken into consideration. Moreover, it is also possible to use not only one type of solvent but also a mixture of two or more types. Furthermore, various surfactants can be used in these coating compositions for the purpose of improving flow during application, especially block or graft copolymers of dimethylpolysiloxane and alkylene oxide. , and fluorine-based surfactants are also effective. Furthermore, it is also possible to add an ultraviolet absorber for the purpose of improving weather resistance, or an antioxidant to improve heat deterioration resistance. As the coating method, methods used in ordinary coating operations can be applied, but for example, dip coating, flow coating, spin coating, etc. are preferable. The coating composition thus applied is dried or cured by heating. As a heating method, hot air, infrared rays, etc. can be used. The heating temperature should be determined depending on the substrate to be applied and the coating composition used, but it is usually from room temperature to 250℃,
More preferably, a temperature of 35 to 200°C is used. If the temperature is lower than this, curing or drying tends to be insufficient, and if the temperature is higher than this, thermal decomposition, cracking, etc. occur, and furthermore, problems such as yellowing are likely to occur. When applying the A film in the present invention, it is preferable that the surface to be applied is cleaned, and cleaning involves removing dirt with a surfactant, degreasing with an organic solvent, and steam cleaning with Freon. etc. apply. Furthermore, it is also an effective means to perform various pretreatments for the purpose of improving adhesion and durability. A particularly preferably used method is chemical treatment with acid, alkali, etc., depending on the concentration. In the present invention, inorganic compounds other than inorganic oxide fine particles can be added to the A coating within a range that does not significantly reduce coating performance, transparency, etc. By using these additives in combination, various physical properties such as adhesion to the substrate, chemical resistance, surface hardness, durability, and dyeability can be improved. The inorganic materials that can be added include metal alkoxides and/or metal alkoxides represented by the following general formula [].
or its hydrolyzate, and further metal chelate compounds. M(OR) _n [] (Here, R is an alkyl group, an acyl group, or an alkoxyalkyl group, and m is the same value as the number of charges of the metal M. M is silicon, titanium, zircon,
They are antimony, tantalum, germanium, and aluminum. ) When the organic polymer contained in Coating A of the present invention is formed from a thermosetting resin, various curing agents can be used for the purpose of accelerating curing, enabling low-temperature curing, etc. As the curing agent, various epoxy resin curing agents or various organosilicon resin curing agents can be used. Specific examples of these curing agents include various organic acids and their acid anhydrides, nitrogen-containing organic compounds, various metal complex compounds or metal alkoxides, and organic carboxylates of alkali metals.
Examples include various salts such as carbonates, and radical polymerization initiators such as peroxides and azobisisobutynitrile. It is also possible to use a mixture of two or more of these curing agents. Among these curing agents, the aluminum chelate compounds shown below are particularly useful for the purpose of the present invention from the viewpoints of stability of the coating material, prevention of discoloration of the coating film after coating, and the like. The aluminum chelate compound mentioned here is
It is an aluminum chelate compound represented by the general formula AlX _o Y _3-o . (However, in the formula, X is OL (L is a lower alkyl group), Y
is a ligand derived from a compound represented by the general formula M ¹ COCH ₂ COM ² (M ¹ and M ² are both lower alkyl groups), and a ligand derived from the compound represented by the general formula M ³ COCH ₂ COOM ⁴ (M ³ and M ⁴ are both lower alkyl groups). is at least one ligand derived from a compound represented by a lower alkyl group), and n is 0, 1 or 2. ) The general formula AlX _o is particularly useful as a curing agent in the present invention.
Among the aluminum chelate compounds represented by Y _3-o , aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, Preferred examples include aluminum di-n-butoxide monoethylacetoacetate and aluminum di-iso-propoxide monomethylacetoacetate. It is also possible to use a mixture of two or more of these. Before forming the B coating, activated gas treatment, chemical treatment, etc. may be performed. In addition, as a method for forming SiO ₂ which is the B film, from the viewpoint of adhesion strength with the A film and improvement of film density, forming means in a vacuum atmosphere is preferable, such as vacuum evaporation method,
Particularly preferred are sputtering method and ion plating method. On the other hand, the surface treatment with activated gas, which is the pretreatment for the A coating, can be performed separately from vacuum evaporation, sputtering, ion plating, etc., but it is better to perform them in the same chamber, as well as improve productivity. This is effective in further improving adhesion. When applying such activated gas treatment, the treatment conditions should be optimized depending on the composition of the A coating, curing conditions, film thickness, presence or absence of dyeing, etc., and should be determined experimentally. It is something. The thickness of the B coating made of SiO ₂ is determined by the desired anti-reflection performance, such as surface hardness, anti-reflection properties, chemical resistance, etc. From this point of view, it is desirable that the optical film thickness at the applied wavelength λ be set to λ/4. Further, a preferred embodiment of the present invention includes an antireflection article in which a transparent base material having a coating A is dyed in advance using a disperse dye or the like, and then the above-mentioned coating B is provided and colored. Although the antireflection article of the present invention has sufficient performance for practical use by itself, a single layer or multilayer antireflection coating may be further provided on the coating of the present invention for the purpose of further enhancing the antireflection effect. It is possible. [Examples] Examples will be described below, but the present invention is not limited thereto. Examples 1 to 3, Comparative Examples 1 to 3 (1) Preparation of transparent substrate to be coated Hydroxyl group-containing compound 1 in which 1 mole of acrylic acid is bonded to 2 moles of ethylene oxide adduct of tetrabromobisphenol A by esterification 70 parts of a monomer containing a polyfunctional acrylate monomer to which 0.9 mol of hexamethylene diisocyanate has been added and 30 parts of styrene were cast-polymerized using isopropyl peroxide as a polymerization initiator, and a base material was subjected to low-temperature plasma treatment to obtain a surface-treated material. A base material was obtained. The refractive index of the obtained resin was 1.6. (2) Preparation of coating composition (a) Preparation of γ-glycidoxypropyltrimethoxysilane hydrolyzate 95.3 g of γ-glycidoxypropyltrimethoxysilane was charged into a reactor equipped with a rotor, and the liquid temperature was 21.8g of 0.01N hydrochloric acid aqueous solution while keeping at 10℃ and stirring with a magnetic stirrer.
Gradually drip. After the dropwise addition was completed, cooling was stopped to obtain hydrolysis of γ-glycidoxypropyltrimethoxysilane. (b) Preparation of paint Add methanol 216 to the silane hydrolyzate.
g, dimethylformamide 216 g, fluorine-based surfactant 0.5 g, bisphenol A type epoxy resin (manufactured by Ciel Chemical Co., Ltd., trade name: Epicoat 827) 67.5 g, and further colloidal antimony pentoxide sol (manufactured by Nissan Chemical Co., Ltd.). 270 g of antimony sol A-2550 (trade name, average particle size 60 mμ) and 13.5 g of aluminum acetylacetonate were added and stirred sufficiently to obtain a coating composition. (3) Preparation of plastic molded article having A coating The coating composition prepared in (2) above was immersed in the resin to be coated obtained in (1) above at a pulling rate of 10 cm/min. The resin was coated, then precured at 82°C for 12 minutes, and further heated at 93°C for 4 hours to obtain a plastic molded article having a coating A. The refractive index of the A film was 1.58, and the film thickness was 2300 nm. (4) Preparation of antireflection article SiO ₂ , which is the B coating, was deposited on the transparent substrate having the A coating obtained in (3) above by vacuum evaporation, and the optical film thicknesses are shown in Table 1. The film thickness was set as shown in . In addition, as a comparative example, only a transparent base material (comparative example 1),
Only the A coating (Comparative Example 2) and the same procedure as in Example 1 except that the inorganic oxide fine particles contained in the A coating were removed (Comparative Example 3)
We also conducted the following performance evaluations. (5) Performance evaluation The performance of the obtained antireflection article was tested according to the following method. The results are shown in Table 1. (a) Rub the painted surface with steel wool with a hardness of #0000.
Assess the degree of injury. The criteria for evaluation are: A: No scratches even with strong friction. B... If you rub it quite strongly, it will get a little scratched. C...Even weak friction can cause damage. (B) Adhesion: Using a steel knife, insert 100 gongs that reach the base material at 1 mm intervals on the coating surface, and firmly adhere cellophane adhesive tape (trade name "Cello Tape" manufactured by Nichiban Co., Ltd.). It was rapidly peeled off in a 90 degree direction and the presence or absence of paint film peeling was examined. (c) Appearance The obtained article was visually observed for its transparency, presence or absence of cracks, etc. (d) Total light transmittance The light transmittance in the entire visible light range was measured.

〔Effect of the invention〕

The antireflection article obtained by the present invention has the following effects. (1) High anti-reflection effect. (2) Has high surface hardness. (3) High adhesion and durability against sweat, etc.

Claims (1)

[Scope of Claims] 1. An antireflection article characterized by having a two-layer structure in which the following coatings A and B are laminated in this order on the surface of a transparent base material. A The refractive index is 1.47 to 1.65, and the film thickness is 100 to
20,000 nm, and a coating made of an organic polymer containing 5 to 80% by weight of inorganic oxide fine particles as a coating component. B A film made of SiO ₂ . 2. The antireflection article according to claim 1, wherein the organic polymer that is a forming component of the A coating is a thermosetting resin. 3. The antireflection article according to claim 1, wherein the B coating is a vacuum-deposited film. 4. The antireflection article according to claim 1, wherein the inorganic oxide fine particles contained in the A coating are one or more selected from antimony oxide, titania, zirconia, and aluminum oxide. 5 By heating the surface of a transparent substrate, the refractive index is 1.47 to 1.65 and the film thickness is 100 to 20000 nm,
and 5 to 5 inorganic oxide fine particles as a coating component.
A method for producing an antireflection article, comprising applying a coating composition capable of forming a coating A consisting of an organic polymer containing 80% by weight, and further providing a coating B consisting of SiO ₂ thereon in a vacuum atmosphere. 6. The method for producing an antireflection article according to claim 5, wherein the organic polymer that is a forming component of the A coating is a thermosetting resin. 6. The method for manufacturing an antireflection article according to claim 5, wherein the B coating is formed by any one of a vacuum deposition method, a sputtering method, and an ion plating method.