JPH1135585A - Fluorine-containing compounds, optical thin films and anti-reflective articles - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] An optical thin film having a low refractive index which is excellent in abrasion resistance and durability and is easy to form. A novel fluorine-containing compound represented by the general formula (1) is synthesized, and the compound has a low refractive index, a high hardness after curing, and is extremely promising as an optical thin film. Was. A specific fluorine-containing compound and a silicon-containing isocyanate compound are synthesized by urethanization reaction. The compound is applied to the substrate surface, polymerized and cured,
An optical thin film having a refractive index not exceeding 1.46 can be formed. It can be used alone or in combination with a hard coat, a high refractive index film, a high conductive film, or the like to prevent light reflection in a resin plate, a resin film, a CRT, a PDP, a liquid crystal panel, a glass, a lens, or the like. Embedded image

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel fluorine-containing compound and a method for producing the fluorine-containing compound, and further relates to a low-refractive-index optical thin film containing the fluorine-containing compound and having excellent scratch resistance. The present invention relates to an antireflection article and an antireflection method using an optical thin film. The optical thin film of the present invention may be used as a CRT, a liquid crystal display, an antireflection filter for a CRT, an antireflection filter for a plasma display,
It can be formed on the surface of articles such as glass and lenses, and can be used to prevent reflection of light rays.

In the present invention, an optical thin film refers to a thin film formed of a transparent thin film on the surface of a substrate and causing interference at a boundary having a different refractive index when a light beam illuminating the substrate is incident on the substrate. That means. Therefore, in the optical thin film, the reflected light appears as interference light of the incident light. The thickness of the optical thin film is usually 1μ
m or less. In the description of the present invention, the refractive index is a measured value at the D line of the sodium emission spectrum, unless otherwise specified, and is a one-sided reflectance (also simply referred to as a reflectance).
Is a measured value in a light beam having a wavelength of 540 nm.

[0003]

2. Description of the Related Art Many conventional anti-reflection articles have a single-layered low-refractive-index optical thin film or a low-refractive-index and high-refractive-index optical thin film alternately laminated on the surface to prevent light reflection. ing.
The reflected light of the optical thin film is interference light of each reflected light on the optical thin film surface or the thin film boundary surface, and the reflectance is reduced or increased by the refractive index and the film thickness of the optical thin film, but the refractive index is low in principle The more it is, the more advantageous in reducing the reflectance. In general, an optical thin film forms an inorganic film on the surface of an article (substrate) by using vapor deposition, sputtering, or the like. The obtained anti-reflection film has low reflectivity and excellent scratch resistance, but the productivity is low and the production cost is high because a vacuum device or the like is used. In addition, there is a problem that the material that can be used is limited because the base material is heated in the manufacturing process.

To solve the above problem, Japanese Patent Laid-Open No.
JP-A-355401 and JP-A-6-18705 disclose a solution coating method in which a low refractive index organic substance is dissolved in a solvent and coated on a substrate to form a low refractive index antireflection film. . By using the solution coating method, it is possible to coat a fluorine-containing resin having a lower refractive index than the magnesium fluoride thin film having the lowest refractive index among the inorganic thin films. Moreover, solution coating is highly productive and economical.

[0005] However, the organic thin film comprising a fluorine-containing resin described in JP-A-4-355401 and JP-A-6-18705 has a low surface hardness due to a low crosslinking density of a cured product of the fluorine-containing resin, and has a low scratch resistance. There was a problem with sex. In addition, the substrate that can be used after coating is required to be cured by heating, so that the usable substrate is limited. In addition, US Pat. No. 3,310,606 discloses a cured product of perfluorodivinyl ether as a fluorine-containing resin having a high crosslinking density and a high surface hardness. An optical thin film cannot be obtained because it needs to be molded below.

Japanese Patent Application Laid-Open No. Hei 8-239430 discloses that a polyfunctional (meth) acrylate is added to 100 parts by weight of a fluorine-containing di (meth) acrylate having a specific structure.
A fluorine-containing curable composition containing 0 to 90 parts by weight and having water repellency, oil repellency and scratch resistance is disclosed. However, this curable composition tends to have a refractive index of more than 1.45, and it is difficult to obtain antireflection properties.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical thin film having low reflectivity, excellent scratch resistance, and which can be easily formed, and an antireflection article using the optical thin film. It was completed as a result of research on the subject.

[0008]

In order to solve the above-mentioned problems, the present inventor synthesizes various compounds including a novel synthetic compound, measures optical characteristics, mechanical characteristics, and the like, and applies the compounds to the optical thin film. The possibility of using was examined. As a result, a new fluorine-containing compound having a structure represented by the general formula (1) was successfully synthesized in Chemical Formula 3, and a cured product of the novel compound had a low refractive index and a high cross-linking property. It has been found that it has high hardness and is very promising, for example, as an optical thin film.

The present invention first provides a novel fluorine-containing compound represented by the following general formula (1) which can solve the above-mentioned problems.

[0010]

Embedded image The fluorine-containing compound represented by the general formula (1) can be produced by subjecting a compound having a structure represented by the following general formula (2) and a compound having a structure represented by the general formula (3) to urethanation reaction. it can.

[0011]

Embedded image The novel fluorine-containing compound represented by the general formula (1) hardens a composition containing this compound and easily has a refractive index of 1.
A thin film not exceeding 46 can be formed, and can be effectively used as an optical thin film. At that time, it is preferable that the thickness of the optical thin film is formed to 30 to 700 nm. Further, the optical thin film can be cured by adding a polyfunctional silane compound in an amount not exceeding 100 parts by weight with respect to 100 parts by weight of the fluorine-containing compound represented by the general formula (1). A polyfunctional silane compound having an epoxy group in an amount not exceeding 100 parts by weight, based on 100 parts by weight of the fluorine-containing compound represented by the general formula (1),
A polyfunctional epoxy resin in an amount not exceeding 100 parts by weight can be added and cured.

When any of the above optical thin films is formed on the surface of a substrate, it is useful as an excellent antireflection article. When an optical thin film is formed on the surface of a substrate, an organic and / or inorganic binder and fine particles of a metal compound are interposed between the surface of the substrate and the optical thin film, and the refractive index is ± 0 of the refractive index of the substrate. By forming a hard coat layer having a thickness within 0.02, the scratch resistance can be increased and the occurrence of interference fringes can be prevented. Further, a high refractive index film having a higher refractive index than the optical thin film and the hard coat layer may be laminated between the base material or the hard coat layer and the optical thin film to improve the antireflection property.

The anti-reflective article has a general formula (2)
And a compound represented by the general formula (3) are dissolved in an organic solvent having no group capable of reacting with isocyanate and reacted at room temperature to 80 ° C., and a coating solution containing the obtained reaction solution is prepared. It can be rationally manufactured by preparing, coating the prepared coating liquid on the surface of the base material and curing, and forming an optical thin film having a refractive index not exceeding 1.46 on the surface of the base material.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described sequentially with reference to specific embodiments. First, a method for producing a fluorine-containing compound represented by the general formula (1), which is a novel compound provided by the present invention, will be described. The compound represented by the general formula (1) can be synthesized by subjecting the fluorine-containing compound represented by the general formula (2) to an isocyanate compound represented by the general formula (3) to undergo a urethanation reaction. The fluorine-containing compound of the general formula (2) can be synthesized by hydrolyzing the compound of the general formula (4).

[0015]

Embedded image Among the fluorine-containing compounds represented by the general formula (2), n
Can easily produce the compound of the general formula (1) by using the compound of 4 to 12. In addition, it is easy to obtain an optical thin film having a low refractive index. On the other hand, among the compounds represented by the general formula (3), the compounds represented by the general formulas (5) to (8)
Can be preferably used. There is an advantage that the crosslinkability of the reaction product is large and the reaction product can be easily produced.

[0016]

Embedded image Specifically, the urethanization reaction was carried out, and the general formula (1)
In order to produce the compound represented by the general formula (2) and the compound represented by the general formula (3), an ester-based, ketone-based, ether-based or hydrocarbon-based compound having a group which reacts with isocyanate It may be dissolved in an organic solvent and reacted at a temperature of about room temperature to about 80 ° C. that time,
For example, a urethanization catalyst such as di-n-butyltin dilaurate can be added to accelerate the reaction rate.
After the urethanization reaction, the solvent is removed by an appropriate means, and the urethanized compound, that is, the compound represented by the general formula (1) can be obtained.

When the compound of the general formula (1) is used for forming an optical thin film, the product of the urethanization reaction is used as a coating solution for forming an optical thin film as a reaction solution without being separated from a solvent. That is, a method of integrally performing the urethanization reaction in the process of preparing the coating liquid is preferable. According to this method, all or a part of the organic solvent is also used as a solvent for the coating liquid.

In the present invention, in order to improve the properties such as the surface hardness and adhesion of the optical thin film and to adjust the refractive index,
A polyfunctional silane compound can be added. The amount of the polyfunctional silane compound added is 10 parts by weight of the polyfunctional silane compound per 100 parts by weight of the compound represented by the general formula (1) of the present invention.
It can be added in a range not exceeding 0 parts by weight, preferably in a range of 90 parts by weight or less. If the amount of the polyfunctional silane compound exceeds 100 parts by weight, the refractive index tends to be 1.46 or more, and the antireflection performance aimed at by the present invention tends not to be exhibited.

The polyfunctional silane compound used in the present invention includes dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxysilane Examples thereof include propyltrimethoxysilane and vinyltriethoxysilane, and these polyfunctional silane compounds can be used alone or in combination of two or more.

Among the polyfunctional silane compounds, those having an epoxy group are preferably used because they have the effect of improving the hardness and the adhesion to the upper and lower layers. When adding a polyfunctional silane compound having an epoxy group, a polyfunctional epoxy resin in an amount not exceeding 100 parts by weight, preferably 90 parts by weight or less, is added to 100 parts by weight of the compound of the general formula (1). Can be added. If the addition amount of the polyfunctional epoxy resin exceeds 100 parts by weight, the refractive index exceeds 1.46, and the antireflection performance of the present invention tends to be unable to be obtained. The optical thin film of the present invention preferably contains the compound represented by the general formula (1) in an amount of 30% by weight or more.

The polyfunctional epoxy resin used in the present invention includes bisphenol A diglycidyl ether, novolak polyglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether. These resins can be added alone or as a mixture of two or more.

Next, the optical thin film of the present invention, which is generally represented by the general formula (1), is prepared by adding the optical thin film of the present invention represented by the above general formula (1) to an organic solvent such as an alcohol, ester, ketone, ether or hydrocarbon. A compound or a coating liquid to which the above-mentioned polyfunctional silane compound is further added is prepared, and the prepared coating liquid is thinly applied to the surface of a substrate, and is polymerized and cured to be formed. Usually, as a pretreatment for coating, a silane-based hydrolyzable group contained in the coating liquid is hydrolyzed. For the hydrolysis, a method of adding an equivalent amount of water and stirring is generally used. However, it is effective to use a small amount of an acid, particularly hydrochloric acid, as a catalyst. A curing agent is added to the coating liquid. As a curing agent, metal chelate compounds such as aluminum, iron, and copper with a long pot life,
For example, it is common to use aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum-di-n-butoxide monoethylacetoacetate, aluminum-di-iso-propoxide monomethylacetoacetate, and the like. The curing agent may be added in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on the entire cured composition.

Further, in order to improve uniform coating properties and adhesion, a chemical such as a leveling agent or a coupling agent is added to the coating solution. These agents are used in an amount of 0.05 to 5 parts by weight, preferably 0.1 to 5 parts by weight of the whole cured composition.
It is advisable to add 2 parts by weight.

The coating solution can be applied without any particular limitation as long as it can be applied uniformly and thinly to the substrate. Specific examples include spin coating, dip coating, die coating, spray coating, bar coater coating, roll coating, and curtain. Means such as flow coat can be used.

In the coating solution, the curable composition for forming the optical thin film of the present invention is preferably heat-cured after being uniformly applied to an optical film thickness. There is no particular limitation on the substrate on which the optical thin film of the present invention can be formed to provide antireflection performance. For example, glass, resin moldings such as polycarbonate and acrylic resin, films such as polyethylene terephthalate film, etc. Can be used effectively. Since the thin film formed of the fluorine-containing compound of the present invention has excellent properties such as water repellency and oil repellency in addition to the above properties, those properties can also be used. There is no particular limitation on the shape of the substrate.

The optical thin film of the present invention can be formed not only as a single layer on a substrate but also as a laminate with another thin film.
For example, the base material may be subjected to a surface treatment in order to improve the adhesiveness and the coatability, or a hard coat layer may be laminated to improve the hardness of the base material to obtain an antireflection article. Further, in order to enhance the antireflection effect of the substrate, an optical thin film having a high refractive index may be formed between the substrate and the optical thin film of the present invention. By alternately laminating the optical thin film and the high refractive index thin film of the present invention, a more excellent antireflection film can be obtained. The high-refractive-index film needs to have a refractive index equal to or higher than that of the base material, and specifically, is preferably at least 1.58, more preferably 1.6.
Above, more preferably 1.7 or more.

A preferred embodiment of an antireflective article formed by laminating the optical thin film of the present invention with another thin film and forming it on the surface of a substrate will be described. In order to impart hardness and prevent interference fringes on the surface of the base material such as polycarbonate or methacrylic resin, the difference in refractive index from the base material is within ± 0.02, and the thickness is 2-5 μm.
It is desired to provide a hard coat layer of a certain degree. The hard coat layer is made of an organic or inorganic binder and, if necessary, ultrafine metal oxide particles such as Si, Sb, Ce, Ti, and Sn, that is, fine particles having a particle diameter smaller than the wavelength of visible light. Use the added coating. Examples of the organic binder include a cured epoxy resin and a resin obtained by radical cross-linking polymerization, and examples of the inorganic binder include a hydrolyzed cured product of a silane-based compound, but are not particularly limited. In general, it is preferable to use a photo-curing method for curing because of a higher curing speed than a thermal curing method.

Further, in order to obtain a high antireflection property by laminating the high refractive index film between the hard coat layer and the optical thin film of the present invention, the high refractive index film must have a thickness of 90 to 400 nm.
More preferably, the thickness is set to 110 to 180 nm. The high-refractive-index film is generally formed by vacuum deposition of a metal oxide or (b) Sb using a (meth) acrylate such as pentaerythritol triacrylate or 2-hydroxy-3-phenoxyacrylate; a silane; an epoxy resin as a binder. , Ce, Ti, Sn and the like. It is preferable that the metal oxide has conductivity, because it can impart a charge retention preventing property. It is preferable that the binder can be cured by a photo-curing method because the curing speed is high.

The present invention provides an optical thin film having a low refractive index for the purpose of reducing the reflectance, and the lower the refractive index, the more advantageous the reduction of the reflectance. The thickness of the optical thin film is λ /
An odd multiple of 4n is preferred. Here, λ indicates the wavelength of light in the thin film, n indicates the refractive index of the thin film, and λ indicates the central wavelength of light when the wavelength of light exists in a certain width. The wavelength of the light targeted in the present invention is often visible light, and the center wavelength is usually 500 to 550, which is usually sensitive to humans.
It is preferably set to nm.

The thickness of the optical thin film of the present invention depends on the refractive index of the thin film, but is preferably 30 to 700 nm, more preferably 40 to 120 nm. Optical film thickness is 3
If it is less than 0 nm, the reduction of the reflectance due to light interference with visible light may be insufficient. Also, when the thickness of the optical thin film exceeds 700 nm, the reflectivity substantially depends only on the reflection at the interface between air and the thin film, so that the reflectivity tends to be insufficiently reduced due to light interference in visible light. For example, when a thin film having a refractive index of 1.38 is provided on a base material having a refractive index of 1.6, the reflectance is 1% or less when the film thickness is an optimum optical film thickness, but the film thickness is several μm or more. In this case, the reflectance is about 3%. The optical thin film has a refractive index of 1.
When it is higher than 46, the effect of the antireflection treatment on a substrate having a relatively low refractive index such as polymethyl methacrylate or glass is not remarkably recognized.

[0031]

EXAMPLES The present invention will be described more specifically with reference to examples. The evaluation means and measurement means used in the following examples and reference examples are as follows. a. Film thickness: Measured with an ellipsometer. b. Single-sided reflectivity: After roughening the back surface of the measurement surface with sandpaper, it is painted black with oil-based ink, and then measured with a spectrophotometer.
The reflectance of the measurement surface at 40 nm was measured.

C. Interference fringes: The sample was allowed to stand 20 cm below the fluorescent lamp stand, and evaluated by visual observation. d. Scratch resistance: Eraser (No. 50 (Lion Corporation)
Was reciprocated 20 times on the reflecting surface with a contact area of about 0.5 cm ² and a load of 1 kg, and was visually judged. Those having no scratches were judged to be acceptable. Further, the present invention will be specifically described with reference to examples.

Example 1 A solution having the composition shown in Table 1 was prepared and reacted at 40 ° C. for 6 hours to obtain a solution R containing a fluorine-containing compound represented by the following structural formula (9). The refractive index of this fluorine-containing compound is
nd = 1.40.

[0034]

Embedded image

[0035]

[Table 1] Next, using the obtained solution R, a coating material A, which is a hydrolysis liquid having the following composition, was prepared.

The coating solution A R 15 parts by weight Isopropanol 85 parts by weight of _^1/10 N hydrochloric acid 0.5 parts by weight Further, spin-coated on the surface of a polycarbonate plate having a thickness of 2mm paint A was formulated, in an open and 80 ° C. 2
Heated for hours. Subsequently, the film is cured at 130 ° C. for 2 hours, and the thickness of the optical thin film of the present invention is 95 nm
A cured film was formed. The refractive index of the formed optical thin film is nd
= 1.44, and the single-sided reflectance was 1.5%.

Reference Example 1 As a blank sample, the same single-sided reflectance of the same polycarbonate plate as used in Example 1 was measured.
%Met.

Example 2 A solution having the composition shown in Table 2 was prepared and reacted at 40 ° C. for 6 hours. The obtained reaction solution (hereinafter, referred to as solution S) contains 2 mol of the compound represented by Structural Formula (b) and 1 mol of the compound represented by Structural Formula (a) in Table 3 containing a urethane bond. A fluorine compound had been synthesized. The measured refractive index of the fluorine-containing compound was 1.39.

[0039]

[Table 2] Using the solution S, a paint B, which is a hydrolysis solution having the following composition, was prepared. Paint B was applied to the surface of a polycarbonate plate and cured in the same manner as in Example 1 to form an optical thin film of the present invention. The refractive index of this optical thin film was nd = 1.44, and the single-sided reflectance was 1.5%.

The formulated coating C is hydrolysis product of the composition according to the coating solution B S 30 parts by weight of methyltriethoxysilane and 2 parts by weight of isopropanol 60 parts by weight of _^1/10 N hydrochloric acid 1.2 parts by weight Example 3 Table 3 did. Paint C was applied to the surface of a polycarbonate plate and cured in the same manner as in Example 1 to form an optical thin film of the present invention. The refractive index of this optical thin film was nd = 1.45, and the single-sided reflectance was 1.7%.

[0041]

[Table 3] Examples 4 to 6 The surface of a polycarbonate plate having a refractive index of 1.59 and a thickness of 2 mm was photocured with ultrafine antimony pentoxide, pentaerythritol triacrylate, and 2-hydroxy-3-phenoxyacrylate as main components. A hard coat layer having a refractive index of 1.59 and a thickness of 3 μm was formed. Further, paints A, B, and C were applied to the surface of the hard coat layer in the same manner as in Example 1, and cured to form an optical thin film. When the formed optical thin films were evaluated, all showed high scratch resistance. Table 4 shows other evaluation results.

[0042]

[Table 4] Examples 7 to 9 A hard coat layer was formed on the surface of a polycarbonate plate in the same manner as in Examples 4 to 6. A composition film mainly composed of antimony-doped tin oxide ultrafine particles, pentaerythritol triacrylate, and 2-hydroxy-3-phenoxyacrylate is laminated on the surface of the formed hard coat layer by photocuring, and has a thickness of 150 nm and a refractive index of nd. = 1.7
A conductive high refractive index layer having a surface resistance of 2 × 109 Ω / □ was obtained. Further, paints A, B, and C were applied on the surface of the high refractive index layer and cured in the same manner as in Example 1 to form an optical thin film. When the formed optical thin films were evaluated, all showed high scratch resistance. Table 5 shows other evaluation results.

[0043]

[Table 5]

[0044]

The cured product of the novel fluorine-containing compound provided by the present invention has an extremely low refractive index, has a high hardness after curing, and is particularly promising as an optical thin film having a low refractive index. And,
It has high surface hardness and excellent scratch resistance and durability. In addition, it has high effects on water repellency and oil resistance. Moreover,
Before curing, since it is soluble in a solvent, it can be applied and cured by economical solution coating, which enables simple and continuous processing and is economical. Further, the low refractive index film of the present invention is formed on the hard coat layer or the high refractive index film to further improve the scratch resistance and the antireflection performance, and to impart multifunctionality. In addition to the optical thin film, it is expected to be used for optical filters, various display members, display members, transparent members, constituent materials of optical devices, and the like.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09K 3/00 C09K 3/00 U G02B 1/11 G02B 1/10 A

Claims (10)

[Claims] 1. A fluorine-containing compound represented by the following general formula (1). Embedded image 2. A compound represented by the following general formula (2) and a compound represented by the following general formula (3) are subjected to a urethanation reaction to produce a fluorine-containing compound represented by the above general formula (1). A method for producing a fluorine-containing compound, characterized in that: Embedded image 3. A composition having a refractive index of 1.4 formed by curing a composition containing the fluorine-containing compound represented by the general formula (1).
An optical thin film comprising a thin film not exceeding 6. 4. A thin film having a thickness of 30 to 700 nm.
The optical thin film according to claim 3, wherein 5. A fluorine-containing compound 1 represented by the general formula (1)
The optical thin film according to claim 3, wherein the polyfunctional silane compound is added and hardened in an amount not exceeding 100 parts by weight with respect to 00 parts by weight. 6. A fluorine-containing compound 1 represented by the general formula (1)
It is characterized by being added and cured with a polyfunctional silane compound having an epoxy group in an amount not exceeding 100 parts by weight and a polyfunctional epoxy resin in an amount not exceeding 100 parts by weight with respect to 00 parts by weight. The optical thin film according to claim 3, 4 or 5, wherein: 7. An antireflective article comprising the optical thin film according to claim 3 formed on a substrate surface. 8. A hard disk comprising an organic and / or inorganic binder and fine particles of a metal compound at an intermediate position between the substrate surface and the optical thin film and having a refractive index within ± 0.02 of the refractive index of the substrate. The antireflective article according to claim 7, wherein a coat layer is formed. 9. A high refractive index film having a higher refractive index than the optical thin film and the hard coat layer is laminated between the substrate or the hard coat layer and the optical thin film. Item 10. An antireflective article according to Item 8. 10. A compound represented by the general formula (2) and a compound represented by the general formula (3) are dissolved in an organic solvent having no group capable of reacting with isocyanate at room temperature to 8 ° C.
A reaction is performed at 0 ° C., a coating liquid containing the obtained reaction solution is prepared, and the prepared coating liquid is applied to the surface of the substrate and cured, and the refractive index on the surface of the substrate does not exceed 1.46. A method for producing an antireflective article, comprising forming a thin film.