JPH11300899A - Optical functional film and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a functional film, wherein an adhesion of a SiO2 gel layer to a base film is improved, maintaining high performance and high-quality characteristics and productivity, and suitable for practical use. SOLUTION: An interlayer 2 composed of a perhydropolysilazane represented by a unit structure of -(SiH2 NH)- and a low-refractive index layer 3 are. formed on a surface of a base film 1 directly or with another layer therebetween. The low-refractive index layer 3 is an SiO2 gel layer composed by gelling an SiO2 sol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an ultraviolet shielding effect,
The present invention relates to an optically functional film excellent in heat ray reflection effect, antireflection effect and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an ultraviolet blocking effect, a heat ray reflecting effect,
A method for forming an optically functional film having an antireflection effect or the like is generally roughly classified into a gas phase method and a coating method. The former method for producing an optically functional film by a gas phase method includes a vacuum deposition method,
There are a physical method such as a sputtering method and a chemical method such as a CVD method. Also, the latter coating method includes a spray method,
There are an immersion method and a screen printing method.

[0003]

The method for producing an optically functional film by a vapor phase method has an advantage that a high-performance and high-quality thin film can be obtained. However, there is a problem that precise atmosphere control in a high vacuum system is required.
Further, a special heating or ion generation accelerating device is required, and there is a problem that the manufacturing cost is inevitably increased because the manufacturing device is complicated and large. Further, there is a problem that it is difficult to increase the area of the thin film or to manufacture a thin film having a complicated shape.

On the other hand, among the methods for producing an optical functional film by a coating method, those using a spray method have problems such as poor utilization efficiency of a coating liquid to be applied and difficulty in controlling film forming conditions. . Also, among the methods for producing an optical functional film by the coating method, the dipping method and the screen printing method are more efficient in using the film forming material than the spraying method, and are advantageous in mass production and equipment cost. There is. However, the optical functional film obtained by these coating methods has a problem that the function and quality are inferior to the film obtained by the gas phase method.

In recent years, as a method for obtaining a thin film of excellent quality by a coating method, a method has been proposed in which a dispersion of inorganic or organic ultrafine particles dispersed in an acidic or alkaline aqueous solution is coated on a substrate and baked. . According to this manufacturing method, there is an advantage that it is advantageous in terms of mass production and equipment costs. However, since a firing process at a high temperature is required during the manufacturing process, there is a drawback that a film cannot be formed on a plastic substrate film. Further, there is also a problem that the uniformity of the thin film is not sufficient due to a difference in the degree of shrinkage between the substrate and the coating film, and the performance is still inferior when compared with a thin film obtained by a gas phase method. Further, the heat treatment requires a long time, for example, several tens minutes or more, and has a disadvantage that productivity is poor.

In order to solve such a problem, the present inventors have already reported the general formula R _m Si (OR ′) _n (where R is an alkyl group having 1 to 10 carbon atoms, a vinyl group, A) an acryloyl group, an epoxy group, an amide group, a sulfonyl group, a hydroxyl group, a reactive group such as a carboxyl group or a group containing these groups, and R ′ represents an alkyl group having 1 to 10 carbon atoms;
m represents an integer of 0 to 3, n represents an integer of 1 to 4, and m + n represents an integer of 4. The SiO ₂ sol prepared by hydrolyzing the silicon alkoxide represented by the formula (1) is applied directly or via another layer on the base film, and the formed coating layer does not damage the base film. A method for efficiently producing a desired high-quality functional thin film without damaging the substrate film by heating or irradiating an active energy ray to form a SiO ₂ gel layer was proposed. However, the SiO ₂ sol obtained by an ordinary method has a practical problem that it easily peels off from the substrate film because of its poor adhesion to the substrate film when formed into a gel film.

In view of the above situation, the present inventors have made intensive studies and as a result, before forming the SiO ₂ gel layer on the base film, the unit structure of the intermediate layer was — (SiH ₂ NH) —
By forming a perhydropolysilazane layer represented by the formula, an optical functional film that has excellent adhesion to a substrate, maintains high-performance and high-quality characteristics and productivity, and can withstand practical use is developed. Reached.

[0008]

That is, in the present invention, the unit structure is-(S) on the surface of the substrate film directly or via another layer.
An intermediate layer made of perhydropolysilazane represented by (iH ₂ NH) — and a low refractive index layer are formed, and the low refractive index layer is a SiO ₂ gel layer obtained by gelling an SiO ₂ sol. And a method for producing the same.

[0009]

Next, the present invention will be described in more detail with reference to preferred embodiments. The optical functional film of the present invention is obtained by imparting various optical functional characteristics to a base film. Specifically, for example, the optical functional film of the present invention is used for various displays such as word processors, computers, and televisions, the surface of polarizing plates used for liquid crystal display elements, sunglass lenses, prescription eyeglass lenses, and optical lenses such as camera finder lenses. This is useful for the purpose of providing a function required for a cover of various instruments, a window glass of a car, a train, and the like, for example, an antireflection function.

The structure of the optical functional film of the present invention will be described with reference to the drawings. FIG. 1 shows that an intermediate layer 2 is formed on the surface of a base film 1 and a low refractive index layer 3 is formed thereon. FIG. 2 schematically illustrates a cross section of the embodiment. FIG. 2 schematically illustrates a cross section of an embodiment in which the low refractive index layer 3 is formed on the base film 1 via the hard coat layer 4 and the intermediate layer 2. FIG. In FIG. 2, the low refractive index layer 3 is formed via the hard coat layer 4 and the intermediate layer 2, but may be formed between the base film 1, the intermediate layer 2 and the low refractive index layer 3 if necessary. For example, another layer such as a transparent conductive layer, an adhesive layer, and a primer layer may be interposed in addition to or instead of the hard coat layer 4.

Examples of the film which can be preferably used as the base film constituting the optical functional film of the present invention include, for example, acetate butyrate cellulose film, polyether sulfone film, polyacrylic resin film, polyurethane resin film, polyester resin Transparent resin films such as films, polycarbonate films, polysulfone films, polyether films, trimethylpentene films, polyetherketone films, and (meth) acrylonitrile films. Among them, particularly, a uniaxially stretched polyester film is preferably used because it is excellent in transparency and has no optical anisotropy. Although the thickness of the base film is not particularly limited, it is usually 8 to 1,
Those having a size of about 000 μm are preferably used.

In the present invention, an intermediate layer is formed on the above-mentioned base film. The unit structure of the intermediate layer is-(S
iH ₂ NH) — is a perhydropolysilazane layer. In the present invention, the use of the perhydropolysilazane layer as an intermediate layer enables a strong adhesion of the SiO ₂ gel layer to the base film. The thickness of the intermediate layer is not particularly limited, but is preferably in the range of about 0.03 to 3 μm. When the thickness of the intermediate layer is less than the above range, the adhesion of the SiO ₂ gel layer to the base film becomes insufficient, and when the thickness of the intermediate layer exceeds the above range, the coating film shrinks sharply, Cracks and the like occur in the film.

The perhydropolysilazane used in the present invention is described in, for example, JP-A-60-145903, D.
Communication of Am. Cer., C-13, January by Seyferth et al.
Polymers disclosed in 1983 and the like, JP-B-6-18885, JP-A-7-223867 and JP-A-9-2
No. 96048, or a cross-linked product thereof, which can be obtained from the market or synthesized by itself and used in the present invention. The perhydropolysilazane used in the present invention has a molecular weight of 500
2,500 (number average molecular weight in terms of polystyrene), but when these perhydropolysilazanes are cross-linked products, the molecular weight may be 500-100,000.

The SiO ₂ gel layer forming the low refractive index layer of the optical functional film of the present invention is formed by gelling SiO ₂ sol.
Consists of _two gels. The method for obtaining the SiO ₂ sol is not particularly limited, but is most preferably prepared by hydrolyzing a silicon alkoxide as described below.

The silicon alkoxide preferably used as a raw material of the SiO ₂ sol is represented by the general formula R _m Si (O
R ′) _n . However, R in the formula represents a reactivity of an alkyl group having 1 to 10 carbon atoms, a vinyl group, a (meth) acryloyl group, an epoxy group, an amide group, a sulfonyl group, a hydroxyl group, a carboxyl group or a group containing these groups. R ′ represents an alkyl group having 1 to 10 carbon atoms, m represents an integer of 0 to 3, n represents an integer of 1 to 4, and m + n is 4.

Specific examples of the compound corresponding to this include, for example, tetramethoxysilane, tetraethoxysilane, tetraiso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-s
tetraalkoxysilanes such as ec-butoxysilane and tetratert-butoxysilane; tetrapentaethoxysilane, tetrapenta-iso-propoxysilane,
Tetrapenta-n-propoxysilane, tetrapenta-
n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane,
Methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, hexyltrimethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- Glycidoxypropyltrimethoxysilane, 3-(-2-aminoethylaminopropyl) trimethoxysilane and the like can be mentioned.

By hydrolyzing the silicon alkoxide,
An SiO ₂ sol can be obtained. The hydrolysis may be performed by dissolving the silicon alkoxide in a suitable solvent. Examples of usable solvents include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone;
Alcohols such as methanol, ethanol and isopropyl alcohol; esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons such as carbon tetrachloride, chloroform and methylene chloride; aromatic hydrocarbons such as toluene and xylene; or mixtures thereof. Can be

The silicon alkoxide is preferably 0.1% in terms of SiO _2, which is assumed to be 100% hydrolyzed and condensed in the solvent.
It is dissolved so as to be at least 0.1% by weight, more preferably 0.1 to 10% by weight. This is because if the concentration of silicon alkoxide in the solvent in terms of SiO ₂ is too small, the characteristics of the optically functional film finally formed may not be sufficiently exhibited, while if the concentration is too large. This is because it may be difficult to form a transparent and homogeneous film. Further, in the solvent in which the silicon alkoxide is dissolved, Si
An organic or inorganic binder can be added as long as it does not hinder the preparation of the O ₂ sol.

In the hydrolysis of the silicon alkoxide, the amount of water required for the hydrolysis or more is added to the solvent in which the silicon alkoxide is dissolved as described above.
The stirring may be performed at a temperature of 5 to 35 ° C, more preferably 22 to 28 ° C, preferably for 5 to 30 hours, more preferably for 12 to 16 hours. In the hydrolysis, it is preferable to use a catalyst. As a catalyst that can be preferably used,
For example, acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid and acetic acid can be mentioned. These acids are preferably from about 0.001-2.
An aqueous solution of 0.0N, more preferably about 0.005 to 5.0N, may be added to the solution in which the silicon alkoxide is dissolved. The water in the added aqueous solution can be used as water for hydrolysis.

The SiO ₂ sol obtained as described above is
It is a colorless and transparent liquid and a stable solution with a pot life of about one month. Therefore, it is most preferably used for forming the SiO ₂ gel layer of the optically functional film of the present invention, because it has good leakage property to the base film and excellent application suitability.

Various additives can be added to the SiO ₂ sol. Most preferred additives include curing agents that promote film formation. Examples of such a curing agent include an organic acid solution such as acetic acid and formic acid of an organic acid metal salt such as sodium acetate and lithium acetate. The concentration of the organic acid solution is preferably about 0.01 to 0.1% by weight. Further, the addition amount relative to the SiO ₂ sol is from about 0.1 to 1 parts by weight of the organic acid salt is preferred for SiO ₂ 100 parts by weight present in the sol.

Further, when the finally obtained optical functional film of the present invention is used for, for example, an antireflection film, a heat ray reflection film, a scattering film, etc., the low refractive index formed by the SiO ₂ gel layer is used. It is preferable to adjust the refractive index of the refractive index layer to about 1.38 to 1.46. Specifically, a fluorine-based organic silicon compound or the like may be added to lower the refractive index of the layer, and an organic silicon compound or the like may be added to increase the refractive index of the layer. Compounds that can be added include, for example, tetraethoxysilane, tetramethoxysilane, tetrapropoxysilane, tetrabutoxysilane, alkyltrialkoxysilane, Corocoat 40 (manufactured by Colcoat), MS51 (manufactured by Mitsubishi Chemical), Snowtex (manufactured by Nissan Chemical) Organic silicon compounds such as Zafflon FC-110, 220, 250 (manufactured by Toa Gosei Chemical), sexual coat A-402B (manufactured by Central Glass), heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, trifluoro Fluorinated organic silicon compounds such as propyltrimethoxysilane; and boron-based compounds such as triethyl borate, trimethyl borate, tripropyl borate, and tributyl borate.

[0023] These additives may be added during the preparation of the SiO ₂ sol may be added after preparation of the SiO ₂ sol. When these additives are used, the additives react with silanol groups during or after hydrolysis of the silicon alkoxide to obtain a more uniform and transparent SiO ₂ sol solution, and the refraction of the formed SiO ₂ gel layer. The rate can be adjusted to some extent.

The low-refractive-index layer of the optical functional film of the present invention is provided on the surface of the intermediate layer formed on the base film by using the SiO 2
₂ It is preferable to apply the sol using a coating method, and then form the coated material as a SiO ₂ gel layer by heating or irradiation with active energy rays. Examples of the method of applying the SiO ₂ sol to the base film include a spin coating method, a dipping method, a spray method, a roll coater method,
Meniscus coater method, flexographic printing method, screen printing method, bead coater method and the like can be mentioned.

Examples of a method for gelling the SiO ₂ sol applied to the base film include methods such as heating and irradiation with active energy rays. The gelation by heating is preferably performed at 150 ° C. or lower, more preferably 120 ° C. or lower, since the damage to the base film must be considered.

When an active energy ray irradiation treatment is used as a method for gelling the SiO ₂ sol, the active energy rays include, for example, electron beams or ultraviolet rays.
In particular, it is preferable to perform gelation with an electron beam. In the case of performing gelation with an electron beam, for example, it is released from various electron beam accelerators such as Cockloft-Walton type, Bande graph type, Resonant transformation type, Insulating core transformer type, Linear type, Dynamitron type and High frequency type 50 to 1,000 KeV,
Preferably, an electron beam having an energy of about 100 to 300 KeV is used.

On the other hand, when gelling is carried out by ultraviolet rays, for example, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp,
It is preferable to use ultraviolet rays emitted from a light source such as a carbon arc, a xenon arc, and a metal halide lamp. When the active energy ray is an electron beam, the total irradiation amount of the active energy ray such as an electron beam or an ultraviolet ray is preferably 2 Mrad or more, more preferably 2 to 50 Mrad.

The electron beam irradiation on the SiO ₂ sol is preferably performed while replacing air with oxygen or in a sufficient oxygen atmosphere.
Formation, polymerization and condensation of ₂ , etc. are promoted, and a more uniform and high quality SiO ₂ gel layer can be formed. The thickness of the SiO ₂ sol layer thus formed is 0.001 to 1
0 μm, and preferably 0.01 to 1 μm. S
When the thickness of the iO ₂ gel layer is less than the above range, it is not preferable in that the optical characteristics as a low refractive index layer are hardly exhibited, and the reflection is large when the thickness of the SiO ₂ gel layer exceeds the above range. It is not preferable in terms of becoming.

In the present invention, the intermediate layer may be formed on the base film via another layer. As the other layers, various layers are possible as described above.
The case where the other layer is the hard coat layer 4 as shown in FIG. In the present invention, the term “hard coat layer” refers to a layer showing a hardness of H or more in a pencil hardness test shown in JIS-K5400.

The hard coat layer is preferably formed using a reaction curable resin. The curable resin has good adhesion to the base film, scratch resistance, hardness, light resistance, moisture resistance, and good adhesion to the low refractive index layer formed on the hard coat layer. If it is, there is no particular limitation. As such a reaction curable resin, for example, a (meth) acrylate of a polyfunctional compound such as an alkyd resin and a polyhydric alcohol (hereinafter, in the present specification, both acrylate and methacrylate are referred to as (meth) acrylate). And ionizing radiation-curable resins (including their precursors) such as those containing relatively large amounts of oligomers or prepolymers and reactive diluents.

Examples of the reactive diluent include monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, vinyltoluene and N-vinylpyrrolidone, and polyfunctional monomers such as trimethylolpropane. Tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6- Hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate and the like can be mentioned.

Further, when the above-mentioned ionizing radiation-curable resin is used as an ultraviolet-curable resin, among these, as a photopolymerization initiator, for example, acetophenones, benzophenones, Michler benzoyl benzoate, α-amilo Xime esters, thioxanthones, and as a photosensitizer, for example, n-butylamine, triethylamine,
A mixture of tri-n-butylphosphine and the like is used.

A reactive organic silicon compound may be used in combination with the ionizing radiation-curable resin. The reactive organic silicon compound is used in a range of 10 to 100% by weight based on the total amount of the ionizing radiation-curable resin and the reactive organic silicon compound. In particular, when an ionizing radiation-curable organic silicon compound is used, it is possible to form a hard coat layer using only this as a resin component. Examples of such an ionizing radiation-curable silicon compound include an organic silicon compound having a molecular weight of 5,000 or less and having a plurality of groups that are reactively crosslinked by ionizing radiation, for example, a polymerizable double bond group. Such a reactive organosilicon compound is a vinyl functional polysilane at one end, a vinyl functional polysilane at both ends, a vinyl functional polysiloxane at one end, a vinyl functional polysiloxane at both ends, or a vinyl functional compound obtained by reacting these compounds. Examples include polysilane or vinyl-functional polysiloxane.

Further, by making the refractive index of the hard coat layer higher than that of the low refractive index layer, the low reflectivity of the optical functional film of the present invention can be further improved. The refractive index of a normal hard coat layer is 1.48 to
Although it is about 1.52, the preferable refractive index of the hard coat layer in the present invention is about 1.55 to 2.50.

In order to make the hard coat layer have a high refractive index,
Ultrafine particles of a metal or metal oxide having a high refractive index can be added to the layer-forming resin component. The ultrafine particles having a high refractive index used in the present invention have a particle diameter of 1 to 50.
nm and a refractive index of about 1.60 to 2.70 are preferable, and specifically, for example, ZnO (refractive index 1.9)
0), TiO ₂ (refractive index 2.3~2.7), CeO ₂ (refractive index 1.95), Sb ₂ O ₅ (refractive index 1.71), SnO
₂ , ITO (refractive index: 1.95), Y ₂ O ₃ (refractive index: 1.8)
7), fine powders such as La ₂ O ₃ (refractive index: 1.95), ZrO ₂ (refractive index: 2.05), Al ₂ O ₃ (refractive index: 1.63).

In order to form a hard coat layer using the reaction-curable resin composition comprising the above components, the above components are dissolved or dispersed in an appropriate solvent to form a coating solution. Apply directly on the substrate film and cure, or
Alternatively, it can also be formed by applying the composition onto a release film and curing it, and then transferring it onto a base film using an appropriate adhesive. When the transfer method is used, the transfer may be performed after the low refractive index layer is formed on the hard coat layer. The thickness of the hard coat layer thus formed is usually about 1 to 50 μm, preferably 3 to 20 μm.
It is about μm.

The other layer may be formed by directly or indirectly applying a desired coating liquid on the transparent substrate film as described above, or on the transparent substrate film. When the hard coat layer is formed by transfer, a coating liquid to be another layer (such as an adhesive layer) is applied on the hard coat layer formed on the release film in advance, and then each layer is laminated. The above-described layers may be transferred to the transparent base film by laminating the release film and the transparent base film with the laminated surface of the release film inside, and then peeling the release film.

As described above, the optical functional film of the present invention
It can be used as a single-layer antireflection film or as a multilayer antireflection film. Further, in the method for producing an optical functional film of the present invention, another optical functional film having a desired function can be obtained by selecting a coating material to be used.

[0039]

The present invention will be described below more specifically with reference to examples and comparative examples. Example 1 (Two-layer type antireflection film) Preparation of sol liquid for forming low refractive index layer Methyltriethoxysilane (MTEOS) is ideally S
The MT is adjusted so that the solid content concentration becomes 3% by weight, assuming that it is hydrolyzed and condensed to iO ₂ or CH ₃ SiO _1.5.
EOS was dissolved in a solvent, methyl ethyl ketone, and stirred for 30 minutes until the liquid temperature was stabilized at 25 ° C. This is designated as solution A.

To solution A, hydrochloric acid having a concentration of 0.005 N as a catalyst was added in an equimolar amount with the alkoxy group of MTEOS, and
Hydrolysis was performed at 5 ° C. for 3 hours. This is designated as solution B.
To this solution B, a mixture of sodium acetate / acetic acid (weight ratio 9/1) as a curing agent was added at 100 mol times the concentration of hydrochloric acid, followed by stirring at 25 ° C. for 1 hour to obtain a SiO ₂ sol. MTEOS was dissolved in methyl ethyl ketone so that the solid concentration would be 1.5% by weight assuming that this SiO ₂ sol was hydrolyzed and condensed to CH ₃ SiO _1.5 ,
_Two sols were obtained.

Synthesis of Perhydropolysilazane 34.4 g of dried 85% sodium cyanate and 100 ml of a mixed solvent of acetonitrile and benzene were placed in a 200 ml flask and kept at 20 ° C. A solution obtained by dissolving 20.3 g of trichlorosilane in a mixed solvent of 20 ml of acetonitrile-benzene was added dropwise over 30 minutes. After the addition was completed, the reaction mixture was stirred at 35 ° C. for 3 hours. After adding about 7 g of decane as a reference substance to this reaction mixture, the solid content was filtered off. Thereafter, the solvent was removed under reduced pressure to obtain triisocyanatosilane.

The obtained triisocyanatosilane was dissolved in ether, and stirred at -60 ° C. for 1.5 hours while introducing gaseous ammonia. By-product NH ₄ NCO was filtered off, and the solvent was distilled off from the filtrate at room temperature. Thereafter, an initiator (trimethylamine) was added and reacted at 150 ° C. for 24 hours to obtain a perhydropolysilazane having a number average molecular weight of 2,000.

Formation of High Refractive Index Hard Coat Layer A PET film (A-4350: trade name, manufactured by Toyobo) having a thickness of 100 μm was prepared as a base film. On the other hand, ZrO ₂ ultrafine particles having a refractive index of 1.9 (No. 1275)
A: Trade name, manufactured by Sumitomo Osaka Cement) and ionizing radiation-curable resin (X-12-2400-6: trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed at a weight ratio of 2: 1. The obtained resin composition was applied on a PET film by gravure reverse coating so as to have a thickness of 7 μm / dry, and the solvent was removed by drying. Thereafter, the coating film was cured by irradiating an electron beam with 5 Mrad at 175 kv to form a high refractive index hard coat layer (refractive index: 1.75).

On the high refractive index hard coat layer obtained in the preparation of the low refractive index layer, first, a 2% by weight xylene solution of perhydropolysilazane synthesized by .1 μm. Then, in the synthesized SiO ₂ sol solution, the thickness of the SiO ₂ gel layer 0.1μ
m. The curing conditions used were the following two methods. That is, (1) heat treatment at 120 ° C. for 1 hour, and (2) 180 ° C. using an electron beam irradiation apparatus.
kv, 20 mAd, one irradiation dose at 20 mA, 2
An antireflection film was obtained in both cases where irradiation was performed 0 times. The refractive index of the formed low refractive index layer is (1) 1.
42, (2) 1.42.

Examples 2 to 5 Instead of methyltriethoxysilane, tetramethoxysilane (Example 2), tetraethoxysilane (Example 3), methyltrimethoxysilane (Example 4), dimethyldiethoxysilane (Example Except that Example 5) was used, the same operation as in Example 1 was performed to obtain a total of eight kinds of two types of antireflection films.

Evaluation of Characteristics of Antireflection Film The optical characteristics of the two types of antireflection films of Example 1 obtained by heating and electron beam irradiation through the above steps (1) to (4) were both such that the total light transmittance was 94.0%. , A haze value of 0.
5. The minimum reflectance in the visible light wavelength region was 1.2, and the antireflection performance was excellent. Further, the evaluation of the adhesion of the SiO ₂ gel layer to the perhydropolysilazane layer on the substrate film by a tape peeling test was 100% in both cases, and the adhesion to the substrate was also good. Also, Example 2
The eight anti-reflection films obtained in Example 5 also obtained almost the same evaluation values as the anti-reflection film of Example 1.

Comparative Example An SiO ₂ sol was obtained under the same conditions as in Example 1. This SiO ₂ sol was applied to a thickness of 0.1 μm on the high refractive index hard coat layer prepared in Example, and
Heat treatment was performed at 0 ° C. for 1 hour to obtain an optical functional film for comparison. In addition, the refractive index of the formed low refractive index layer was 1.42. The optical properties of this optical functional film for comparison were 94.0% in total light transmittance, 0.5 haze, and the minimum reflectance in the visible light wavelength region was 1.2. The antireflection performance equivalent to that of the film was exhibited. However, in the evaluation of the adhesion of the SiO ₂ gel layer to the substrate film by a tape peeling test, partial peeling of the coating film was observed.

[0048]

As described above, according to the present invention, when the SiO ₂ sol is applied to the base film to form the low refractive index layer composed of the SiO ₂ gel layer, the unit structure is-(SiH ₂ NH)- By using the perhydropolysilazane layer represented by the formula (1) as an intermediate layer, an SiO ₂ gel layer having improved adhesion to a substrate can be obtained while maintaining optical characteristics. Such S
The iO ₂ sol is sufficiently cured at a temperature that does not damage the base film, and an SiO ₂ gel film having the same characteristics can be obtained by irradiation with active energy rays. Optical functional films using these gel films have excellent optical characteristics such as an antireflection effect.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a cross section of an optical functional film of the present invention.

FIG. 2 is a diagram schematically illustrating a cross section of the optical functional film of the present invention.

[Explanation of symbols]

 1: base film 2: intermediate layer 3: low refractive index layer 4: hard coat layer

Claims (7)

[Claims] 1. An intermediate layer comprising a perhydropolysilazane whose unit structure is represented by-(SiH ₂ NH)-and a low refractive index layer formed directly or via another layer on the surface of a substrate film. An optically functional film, wherein the low refractive index layer is an SiO ₂ gel layer obtained by gelling an SiO ₂ sol. 2. The method according to claim 1, wherein the SiO ₂ sol has the general formula R _m Si (O
R ′) _n (where R represents an alkyl group having 1 to 10 carbon atoms, a vinyl group, a (meth) acryloyl group, an epoxy group,
An amide group, a sulfonyl group, a hydroxyl group, a carboxyl group or a reactive group such as a group containing these groups; R ′ represents an alkyl group having 1 to 10 carbon atoms; m represents a number of 0 to 3; n represents the number of 1-4, and m + n is 4. The optical functional film according to claim 1, which is a SiO ₂ sol prepared by hydrolyzing a silicon alkoxide represented by the formula (1). 3. The optical functional film according to claim 1, wherein the thickness of the intermediate layer is 0.03 to 3 μm. 4. The low refractive index layer has a refractive index of 1.38 to 1.4.
The optically functional film according to claim 1, which is 6. 5. The optical functional film according to claim 1, wherein the base film is a uniaxially stretched polyester film. 6. The optical functional film according to claim 1, wherein the other layer is a hard coat layer. 7. An SiO ₂ sol is applied to the surface of an intermediate layer composed of perhydropolysilazane having a unit structure represented by — (SiH ₂ NH) — formed on a base film, and then heated or activated by an active energy ray. Irradiation treatment and SiO ₂
The method for producing an optically functional film according to any one of claims 1 to 6, wherein a gel layer is formed.