JPH10279531A - Fluorine-containing compound, optical thin film and reflectionproof article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily obtain the subject new compound having unsaturated double bond group and polar group in the molecule, and useful as a raw material for optical thin film excellent in such low reflectivity and scratch resistance as to be used in reflectionproof articles. SOLUTION: This compound is shown by the formula (CH2 =CR1COOR2)2 Rf (R1 is H or methyl; R2 is a 1-10C alkyl bearing one hydroxyl group; Rf is a fluoroalkyl) [e.g. CH2 =CHCOOCH2 CH(OH)CH2 (CF2 )8 CH2CH(OH)CH2 OCOCH= CH2 ]. The compound of the formula is obtained by reaction between a fluorine- contg. diepoxy compound and a carboxyl group-bearing (meth)acrylate in the equivalent ratio of the latter to former of (0.3-2.0) [pref. (0.5-1.5)] pref. using a catalyst such as pyridine and a polymerization inhibitor such as metoquinone pref. at 40-150 deg.C (more pref. 50-130 deg.C) for 2-80 h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluorine-containing compound,
Optical thin films and anti-reflection articles using the same, particularly for anti-reflection of various display devices such as anti-reflection films for television cathode-ray tubes, liquid crystal display devices, and anti-reflection filters for CRT monitors, as well as for display cases The present invention relates to an optical thin film and an anti-reflective article suitably used for anti-reflection of, for example, an anti-reflection film, a show window, a picture frame, a window glass, an optical lens, an eyeglass lens and the like.

[0002]

2. Description of the Related Art An antireflection article such as an antireflection filter used for a display device or the like has a low refractive index optical thin film provided on a substrate in a single layer, or a high refractive index and low refractive index optical thin film. In many cases, the anti-reflection layer is formed by alternately providing multiple layers.

A method for obtaining such an optical thin film is as follows.
In general, an inorganic substance is laminated on a substrate by vapor deposition, sputtering, or the like, and the antireflection film thus obtained has low reflection and excellent scratch resistance. However, the method of performing antireflection treatment by vapor-depositing or sputtering an inorganic substance, although a high-performance antireflection layer can be obtained, is inferior in productivity because a large-scale apparatus requiring vacuum is used, and the production cost is expensive. . Further, in these methods, the substrate is heated to 80 ° C. or more during vapor deposition or sputtering, so that the usable substrates are limited in terms of heat resistance and the like.

Recently, there has been known a method of dissolving a low-refractive-index organic substance in a solvent, coating the substrate with a low-refractive-index organic substance to form a low-refractive-index organic thin film to form an antireflection film. It became so. Such a solution coating method is disclosed, for example, in JP-A-4-355401 and JP-A-6-355601.
No. -18705. The low refractive index substance used in these solution coating methods is a resin having a high fluorine content, and exhibits excellent antireflection characteristics. In addition, since these form a thin film by solution coating, it is possible to form an anti-reflection film with high productivity, unlike the method of performing anti-reflection treatment by vapor deposition or sputtering of an inorganic substance.

However, the organic thin film made of a fluorine-containing resin described in JP-A-4-355401 or JP-A-6-18705 has a high productivity because it can be solution-coated, and has an excellent reflection due to a low refractive index. Although they exhibit prevention properties, these cured fluorine-containing resins have low cross-linking densities and thus have low surface hardness and poor abrasion resistance. Furthermore, since heat curing is required after coating, usable substrates are limited in terms of heat resistance and the like.

Further, as a fluorine-containing resin having a high surface hardness and a high crosslinking density, a cured product of perfluorodivinyl ether disclosed in US Pat. No. 3,310,606 is cited. Insoluble in solvent and high temperature,
Since it is necessary to mold under high pressure, an optical thin film cannot be obtained.

On the other hand, JP-A-8-239430 proposes a fluorine-containing di (meth) acrylate having a specific chemical structure. However, these compounds generally have low polarity, and have caused a problem in adhesion to the lower layer. Further, there is a problem that the esterification and purification steps require time and effort for producing the compound.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to an optical thin film having excellent low reflectivity and scratch resistance, an antireflection article using the same, and an unsaturated double bond group and a polar group as raw materials thereof. It is an object of the present invention to provide a novel fluorine-containing compound having the following formula:

[0009]

In order to achieve the above object, the present invention has the following arrangement.

(1) A fluorine-containing compound represented by the following general formula: (CH2 = CR1COOR2) 2Rf (wherein, R1 represents a hydrogen atom or a methyl group, and R2 represents 1
Represents an alkyl group having 1 to 10 carbon atoms having two hydroxyl groups,
Rf represents a fluorine-containing alkyl group. In addition, the optical thin film of the present invention has the following configuration.

(2) An optical thin film obtained by polymerizing a composition containing a fluorine-containing compound represented by the above general formula.

(3) An anti-reflective article obtained by using the optical thin film according to (2).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The optical thin film of the present invention is a thin film in which, when a light beam enters a base material on which a thin film is present, the light beam intersects at a boundary having a different refractive index to cause interference. In an optical thin film, reflected light appears as interference light of incident light.
For example, when a transparent optical thin film is provided on a transparent substrate, part of the incident reflected light is reflected at the boundary between air and the thin film,
Part is reflected at the interface between the thin film and the substrate, and the reflected light as a whole becomes their interference light. The interference light results in a reduction or increase in the reflectivity of the substrate. The optical thin film is thin enough to cause interference of light, and the reflectance of the substrate depends on the refractive index and the thickness of the optical thin film.

Although the present invention is not limited in application, the present invention mainly provides an optical thin film having a low refractive index for the purpose of reducing the reflectance, and the optical thin film has a thickness of λ / 4.
An odd multiple of n is preferred. Here, λ indicates the wavelength of the light in the thin film, and when the wavelength of the light exists in a certain width, λ indicates the central wavelength of the light. n represents a film refractive index. The wavelength of light to be used in the present invention is visible light in many cases, and the center wavelength is preferably set to 500 to 550 nm, which is usually felt by humans.

The thickness of the optical thin film of the present invention depends on the refractive index of the film, but is preferably from 70 to 700 n from the viewpoint of exhibiting the effect of reducing the reflectance due to light interference in visible light.
m, more preferably 80 to 120 nm, even more preferably 90 to 110 nm.

When a low refractive index film is provided on the surface of an article thicker than the optical film thickness to provide antireflection, there is no effect of reducing the reflectance due to light interference and the reflection due to the low refractive index of the substrate surface. Since only the reduction of the reflectance is achieved, the reflectance is higher and the antireflection effect is inferior to the case where the optical thin film is provided.

In order to enhance the anti-reflection effect, the value of the refractive index of the substrate itself or the film on the surface of the substrate measured by D-line is 1.5.
6 or more, preferably 1.6 or more, more preferably 1.
It is preferable to use a material having a relatively high refractive index of 70 or more, and provide a film having a lower refractive index than the film on the substrate or the substrate surface. Further, when the film has a film on the surface of the base material, the film has a refractive index preferably in the range described later, and may further have conductivity. For example, when a thin film having a refractive index of 1.38 is provided on a substrate having a refractive index of 1.6, the reflectance can be 1% or less by appropriately selecting the thickness of the thin film.

Polymethyl methacrylate (hereinafter referred to as PMM)
From the viewpoint of providing an antireflection effect even for a substrate such as A) or glass having a refractive index lower than 1.56, the refractive index of the optical thin film provided on the substrate is set to 1.45 or less, and further to 1. 4
It is preferably set to 2 or less.

In the optical thin film of the present invention, the surface hardness after polymerization is higher than the pencil hardness H. If the surface hardness is low, there is a problem that the resulting film has poor scratch resistance and durability is reduced.

The fluorine-containing compound having two or more unsaturated double bonds used in the present invention has the following general formula (CH2 = CR1COOR2) 2Rf (wherein R1 represents a hydrogen atom or a methyl group, and R2 represents 1
Represents an alkyl group having 1 to 10 carbon atoms having two hydroxyl groups,
Rf represents a fluorine-containing alkyl group. ), But R
1, R2 and Rf may each be linear or branched.

Examples of such a fluorine-containing compound having two unsaturated double bonds include the following compounds.

[0022]

Embedded image

Embedded image

Embedded image In the above general formula, k is an integer of 2 or more and 12 or less. From the viewpoint of reducing the refractive index and improving the scratch resistance, k is preferably 4 or more and 10 or less.

The method for synthesizing the fluorine-containing compound of the present invention will be described below. A fluorinated di (meth) acrylate obtained from a fluorinated diepoxy compound and a (meth) acrylate having a carboxyl group has a hydroxyl group content of 0.1 equivalent to 1 equivalent.
It can be produced by reacting at a ratio of 3 to 2.0 chemical equivalents, more preferably 0.5 to 1.5 chemical equivalents.

At this time, a reaction solvent can be added,
As a substance corresponding to these, any solvent can be used as long as it can dissolve both, and an organic solvent is generally used.

Further, it is preferable to use a catalyst for the purpose of accelerating the reaction. For example, pyridine, isoquinoline, N, N-dimethylcyclohexylamine, picoline, triethylamine, tributylamine, N, N-dimethylaniline, benzyltriethylammonium chloride, triphenylphosphine, potassium hydroxide, sodium hydroxide, BF3 and the like are used. . The amount used is preferably 0.1 to 15 parts with respect to the reaction raw material mixture.
% By weight, more preferably 0.3 to 5.0% by weight.

In order to inhibit the polymerization during the reaction, it is preferable to use a polymerization inhibitor.
For example, metoquinone, hydroquinone, phenothiazine and the like can be mentioned. The addition amount is preferably 0.01 to 5%, more preferably 0.05 to 3%, based on the reaction raw material mixture.

The reaction temperature varies depending on the diluting solvent and catalyst, but is preferably a temperature at which thermal polymerization of the raw materials, reaction intermediates and products does not occur, preferably from 40 to 150 ° C, more preferably from 50 to 130 ° C. The reaction time depends on the catalyst and the reaction temperature, but is 2 to 80 hours. After the reaction,
Unreacted (meth) acrylate, diluting solvent and the like can be distilled off, and they can be used next without removing them. In addition to the fluorine-containing compound having two unsaturated double bonds described above, if necessary, a fluorine-containing compound having an unsaturated double bond, a polymerization initiator, and other monomers and compounds are added to the composition. be able to. These monomers and compounds are appropriately added for adjusting hardness, refractive index, coating property, and the like, and can be polymerized into an optical thin film.

Examples of such a fluorine-containing compound having one unsaturated double bond include 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2 , 3,4,4,4
Monofunctional fluorine-containing (meth) acrylates such as hexafluorobutyl methacrylate, perfluorooctylethyl acrylate, and β- (perfluorooctyl) ethyl methacrylate. In order to lower the refractive index of the optical thin film, it is preferable to add a compound having a high fluorine content containing one unsaturated double bond. Further, the hardness of the optical thin film can be increased by adding a small amount of a difluorovinyl compound.

Further, commercially available polyfunctional monomers and the like can be added to the composition for adjusting the hardness and refractive index and imparting other properties. The use amount of the polyfunctional monomer is preferably 50% by weight or less, more preferably 40% by weight or less, from the viewpoint of preventing the refractive index from increasing and the antireflection performance from decreasing.

Examples of such polyfunctional monomers include, for example, triethylene glycol di (meth) acrylate,
Polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-
Hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and the like can be mentioned, provided that they have good compatibility and can obtain a cured product having a pencil hardness of H or more. There is no particular limitation.

In order to further improve the coating property, a leveling agent having an effect of smoothing the surface of the coating film may be added.
-5% by weight, more preferably 0.1-2% by weight.

The polymerization method for the optical thin film of the present invention, such as a thermal polymerization method, a photopolymerization method, and an electron beam polymerization method, is not particularly limited, but is preferably cured by a photopolymerization method which is not affected by the heat resistance of the substrate. You. As the thermal polymerization initiator, peroxide compounds and the like are used in addition to azo compounds such as azoisobutyronitrile. Examples of the photopolymerization initiator include, for example, isopropylthioxanthone, 2-hydroxy-2-methyl-1-phenylpropan-1-one,
-Hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, and the like, but are not particularly limited thereto. The addition amount of the photopolymerization initiator is 0.1% of the whole cured product composition.
It is 1 to 20% by weight, preferably 0.1 to 10% by weight.

In the present invention, if necessary, a composition containing a photopolymerization initiator, a commercially available polyfunctional monomer, a leveling agent, etc., as it is or diluted to an appropriate concentration with an appropriate solvent is coated on a substrate. For example, it is uniformly applied by a method such as spin coating, dip coating, die coating, spray coating, bar coater coating, roll coating, curtain flow coating and the like. Then, after the solvent is distilled off by heating or the like, an effect film is formed by heating or light irradiation. Above all, ultraviolet irradiation using a low-pressure or high-pressure mercury lamp, a xenon lamp or the like is preferable.

The substrate provided with anti-reflection performance by the optical thin film of the present invention is not particularly limited. For example, ordinary glass, thin glass having a thickness of 1 mm or less, polycarbonate resin, PMMA resin, polyethylene terephthalate (PE)
T) Resin transparent substrates such as resins, films such as PET films, and the like.

When the optical thin film of the present invention is formed on a base material, the base material may be subjected to a surface treatment or a base material of the present invention, if necessary, for the purpose of improving adhesion and coating properties. An intermediate film can be provided between the optical thin film. When an optical thin film having a higher refractive index than that of the optical thin film is provided as the intermediate film, the antireflection effect is enhanced. A protective article can be obtained. In order to enhance the antireflection effect, the refractive index when the film is provided on the substrate surface is equal to or higher than the substrate, 1.56 or more,
Further, it is preferably 1.6 or more, particularly preferably 1.7 or more. The method and material for forming the high refractive index film are not particularly limited. Further, those obtained by imparting conductivity to these high refractive index films can also be preferably used. Further, the optical thin film of the present invention can impart not only low reflectivity but also water repellency due to the effect of elemental fluorine.

[0036]

EXAMPLES The present invention will be specifically described with reference to examples.

[Synthesis of fluorinated di (meth) acrylate] 0.05 mol of fluorinated diepoxy represented by the following formula:
l, 0.10 mol of (meth) acrylic acid, hydroquinone 1
40 mg, 240 mg of triethylbenzylammonium chloride, and 50 g of a solvent were charged into a 500-cc three-necked flask completely replaced with nitrogen and equipped with a stirrer, a thermometer, and a condenser, and heated and stirred at 70 ° C. for 5 hours under a nitrogen purge.

[0038]

Embedded image The solvent is distilled off, and the fluorine-containing diacrylate having an unsaturated double bond of the present invention CH2 = CHCOOCH2CH (OH) CH2 (CF2) 8CH2CH (OH) CH2OCOCH = CH2 (I) CH2 = CHCOOCH (CH2OH) CH2 ( CF2) 8CH2CH (CH2OH) OCOCH = CH2 or dimethacrylate CH2 = C (CH3) COOCH2CH (OH) CH2 (CF2) 8CH2CH (OH) CH2OCOC (CH3) = CH2 (II) CH2 = C (CH3) COOCH (CH2OH) CH2 (CF2) 8CH2CH (CH2OH) OCOC (CH3) = CH2 was obtained.

Example 1 Fluorine-containing compound (I) having an unsaturated double bond of the present invention
Five parts, 0.2 part of isopropylthioxanthone as a photoinitiator and 90 parts of isobutanol were mixed and stirred to prepare a coating solution. The coating solution was applied to a hard-coated polycarbonate substrate by a dip coating method so as to have a film thickness of 100 nm, and then irradiated with UV at 5,000 mJ / cm 2 for 3 minutes using a high-pressure mercury lamp to polymerize. The refractive index of the hard-coated polycarbonate substrate was 1.59. Table 1 shows the reflectance at 540 nm of the optical thin film substrate, the pencil hardness of the polymer cured product, the refractive index at D line, and the eraser resistance of the thin film.

The obtained optical thin film substrate has low reflectance,
And it was excellent in scratch resistance. In addition, the eraser resistance of the thin film was evaluated using an eraser of LION, No. 50.
Evaluation was made by observing the presence or absence of scratches after five reciprocations under a load of 1 kg.

Example 2 Fluorine-containing compound (II) having an unsaturated double bond of the present invention
An optical thin film was prepared and evaluated in the same manner as in Example 1 except that was used. The results are shown in Table 1.

Example 3 Fluorine-containing compound of the present invention having an unsaturated double bond CH2 = C (CH3) COOCH2CH2CH (OH) OCO (CF2) 6COOCH (OH) CH2CH2O
80 parts of COC (CH3) = CH2 and perfluorooctylethyl acrylate 1
5 parts, trimethylolpropane triacrylate 5 parts,
900 parts by weight of isobutanol, and 1-
One part of hydroxycyclohexyl phenyl ketone was mixed and stirred to prepare a coating solution. A coating solution is applied on a hard-coated polycarbonate substrate by spin coating to a thickness of 1 μm.
After coating to a thickness of 00 nm, the mixture was irradiated with 5000 mJ / cm2 UV for 3 minutes using a high-pressure mercury lamp to polymerize. The refractive index of the hard-coated polycarbonate substrate was 1.59.

The reflectance of the obtained optical thin film substrate at 540 nm, the pencil hardness of the polymer cured product, the refractive index at D line, and the eraser resistance of the thin film are also shown in Table 1.

The obtained optical thin film substrate had a low reflectance and was excellent in scratch resistance.

Example 4 Fluorine-containing compound (I) having an unsaturated double bond of the present invention
95 parts, 5 parts by weight of pentaerythritol tri (meth) acrylate, and 2-methyl-1- as a photoinitiator
1 part by weight of [4- (methylthio) phenyl] -2-morpholinopropanone-1, and S as a leveling agent
H190 (Toray Dow Corning Silicone Co., Ltd.)
Of n-butyl acetate 50 as a solvent.
The parts by weight were mixed and stirred to prepare a coating solution. On a polycarbonate substrate, a hard coat having a refractive index of 1.7 and a thickness of 150 nm made of a mixture of a metal oxide and a polyfunctional acrylate is formed, and the coating liquid is further formed thereon by spin coating to a thickness of 100 nm. After applying,
5000mJ / cm2 U for 3 minutes using high pressure mercury lamp
V irradiation and polymerization were carried out to form a two-layer film of a high refractive index thin film and a low refractive index thin film on a polycarbonate substrate.

The reflectance at 540 nm of the optical thin film substrate, the pencil hardness of the polymerized cured product, the refractive index at D line,
Table 1 shows the eraser resistance of the thin film.

The obtained optical thin film substrate had low reflectance and excellent scratch resistance.

Example 5 An optical thin film substrate was produced in the same manner as in Example 1 except that the paint-coated substrate was changed to PMMA.

The reflectance of the obtained optical thin film substrate at 540 nm, the pencil hardness of the polymerized and cured product, the refractive index at D line, and the eraser resistance of the thin film are also shown in Table 1.

The obtained optical thin film substrate had low reflectance and excellent scratch resistance.

Comparative Example 1 5 parts by weight of neopentyl glycol diacrylate, 0.4 part by weight of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photoinitiator and 90 parts by weight of isopropyl alcohol were mixed. By stirring, a coating solution was prepared. The coating solution was applied on a polycarbonate substrate hard-coated by a dip coating method so as to have a thickness of 100 nm, and then 5,000 mJ for 3 minutes using a high-pressure mercury lamp.
/ Cm 2 UV irradiation for curing. The refractive index of the hard-coated polycarbonate substrate was 1.59.

The reflectance at 540 nm of the optical thin film substrate, the pencil hardness of the polymerized cured product, the refractive index at D-line,
Table 1 shows the eraser resistance of the thin film.

The antireflection effect of the obtained thin film was low.

Comparative Example 2 A thin film was formed on a PMMA substrate in the same manner as in Comparative Example 1 except that PMMA was used as the substrate. The refractive index of the PMMA substrate was 1.50.

Table 1 also shows the reflectance at 540 nm, the pencil hardness of the polymerized cured product, the refractive index at the D line, and the eraser resistance of the thin film.

The antireflection effect of the obtained thin film was low.

Comparative Example 3 Commercially available fluorine-containing resin (CYTOP, manufactured by Asahi Glass Co., Ltd.)
2% solution was applied to a hard-coated polycarbonate substrate by dip coating to a thickness of 100 nm, and dried at 90 ° C. for 1 hour to obtain an optical thin film. The refractive index of the hard coat film was 1.7.

Table 1 also shows the reflectance at 540 nm, the pencil hardness of the cured polymer, the refractive index at the D line, and the eraser resistance of the thin film.

The cured product was soft and scratched by the eraser.

Comparative Example 4 A commercially available fluorine-containing resin represented by the following chemical formula C8H17 (CH2) 2OCOC (CH3) = CH2 (Mitsubishi Rayon Co., Ltd.)
3% solution obtained by dissolving 3 parts by weight of FM17) in 97 parts by weight of perfluoro-2-butyltetrahydrofuran was applied to a hard-coated polycarbonate substrate with a film thickness of 1%.
After applying by the dip coating method to become 00 nm,
After drying at 80 ° C. for 1 hour, an optical thin film was obtained. 540n
Table 1 also shows the reflectance at m, the pencil hardness of the polymerized cured product, the refractive index at D line, and the eraser resistance of the thin film. The refractive index of the hard coat film was 1.7.

It became a soft polymerized and cured product, and was scratched by the eraser.

[0062]

[Table 1]

[0063]

The fluorine-containing compound of the present invention is a material which is excellent in abrasion resistance, has good weather resistance and heat resistance, and forms an antireflection optical thin film having good coatability. Such an optical thin film has water repellency as well as antireflection properties.

The anti-reflective article obtained from the optical thin film of the present invention is used for anti-reflection of various display devices such as a CRT of a television, an anti-reflection film for a liquid crystal display, and an anti-reflection filter for a CRT monitor. It can be used as a case, show window, picture frame, window glass, optical lens, eyeglass lens, etc.

Claims (11)

[Claims] 1. A fluorine-containing compound represented by the following general formula: (CH2 = CR1COOR2) 2Rf (wherein, R1 represents a hydrogen atom or a methyl group, and R2 represents 1
Represents an alkyl group having 1 to 10 carbon atoms having two hydroxyl groups,
Rf represents a fluorine-containing alkyl group. ) 2. R2 is CH2CH (OH) (CH2) q or CH (CH2OH) (CH
2. The method according to claim 1, wherein q is an integer of 1 to 3.
The fluorine-containing compound according to the above. 3. An optical thin film obtained by polymerizing a composition containing a fluorine-containing compound represented by the following general formula. (CH2 = CR1COOR2) 2Rf (wherein, R1 represents a hydrogen atom or a methyl group, and R2 represents 1
Represents an alkyl group having 1 to 10 carbon atoms having two hydroxyl groups,
Rf represents a fluorine-containing alkyl group. ) 4. A fluorine-containing compound 10 represented by the following general formula:
An optical thin film obtained by polymerizing a composition obtained by adding 50 parts by weight or less of a polyfunctional (meth) acrylate to 0 parts by weight. (CH2 = CR1COOR2) 2Rf (wherein, R1 represents a hydrogen atom or a methyl group, and R2 represents 1
Represents an alkyl group having 1 to 10 carbon atoms having two hydroxyl groups,
Rf represents a fluorine-containing alkyl group. ) 5. The method according to claim 4, wherein the polyfunctional (meth) acrylate is a trifunctional or tetrafunctional (meth) acrylate.
3. The optical thin film according to claim 1. 6. In the above general formula, Rf is (CF2) k
The optical thin film according to claim 3, wherein k is an integer of 2 or more and 12 or less. 7. The optical thin film according to claim 3, wherein Rf is (CF2) m (m is an integer of 4 or more and 10 or less). 8. The optical thin film according to claim 3, wherein the refractive index at D line is 1.45 or less. 9. The optical thin film according to claim 3, wherein the optical thin film is polymerized by light. 10. An antireflective article comprising the optical thin film according to claim 3 on a substrate. 11. An anti-reflective article comprising the optical thin film according to claim 3 provided on a substrate provided with a high refractive index film having a refractive index of 1.56 or more. .