JP2003251750A - Optical film having coating layer for reducing interactive mottle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film which has a good solvent resistance and flaw resistance without an interactive mottle, and is used as a basic material for all types of optical film. <P>SOLUTION: This is an optical film which has a coating layer made of a curing-type resin with a membrane thickness being 0.01 μm to 20 μm on at least one surface of a high-molecular film with a total light transmission factor being over 80%, and satisfies the following formula (a) in case the refraction factor of the coating layer is n<SB>1</SB>and the refraction factor of the high-molecular film is n<SB>2</SB>. |n<SB>2</SB>-n<SB>1</SB>|≤0.02 (a) (in the said formula, the refraction factors n<SB>1</SB>, n<SB>2</SB>are measured at 25°C using a 589-nm wavelength of sodium D-ray. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical film and a method for producing the same, and more particularly, to an optical film having less interference spots by providing a coating layer on a polymer film and a method for producing the same.

[0002]

2. Description of the Related Art Since polymer films are generally weak against solvents and scratches, their utility value is greatly expanded by imparting properties such as solvent resistance and scratch resistance. To impart solvent resistance and scratch resistance, a polymer film is usually coated by a dry method or a wet method, and a coating layer is provided on the surface thereof.
However, in this case, reflection occurs at the interface between the coat layer and the polymer film, and interference spots due to this are likely to occur, which is a cause of degrading the quality of the polymer film for optical use.

[0003]

The main object of the present invention is to:
An object of the present invention is to provide an optical film which is excellent in solvent resistance and scratch resistance, has less interference spots, and is a base material for all optical films.

[0004]

In order to achieve the above object, the authors of the present invention have focused on a cost-effective coating method by a wet method. It has been found that the coating layer formed on the polymer film by this method is difficult to have a uniform film thickness with high accuracy. In particular,
In an optical film used as a substrate for various displays, extremely high visibility is required, but it has been found that subtle unevenness in thickness causes interference spots of reflected light, that is, reduction in visibility. . Therefore, focusing on the interface between the coating layer and the polymer film that causes reflection, reducing the difference in the refractive index between them, and suppressing the generation of the reflected light itself, an optical film with good visibility can be obtained and the present invention can be obtained. I arrived.

That is, the present invention is as follows. 1. At least one surface of the polymer film having a total light transmittance of 80% or more is made of a curable resin and has a thickness of 0.
An optical film having a coat layer of 01 μm to 20 μm, which satisfies the following formula (a), where n _{1 is} the refractive index of the coat layer and n ₂ is the refractive index of the polymer film. | N ₂ −n ₁ | ≦ 0.02 (a) (Here, the refractive indices n ₁ and n ₂ are measured at 25 ° C. and the wavelength of sodium D line of 589 nm.)

2. The coating layer is composed of a curable resin produced by applying active energy ray irradiation and / or heat after applying a coating composition containing a monomer having a fluorene skeleton in the molecular structure on at least one side of the polymer film. the film.

3. The coating layer comprises a curable resin produced by irradiating active energy rays and / or heat after applying a coating composition containing at least two kinds of monomers having different refractive indexes to at least one surface of the polymer film. the film.

4. A monomer having a fluorene skeleton in the molecular structure is represented by the following formula (b):

[0009]

[Chemical 4]

[In the above formula (b), R _{1 and} R ₂ are each independently a divalent hydrocarbon group having 2 to 6 carbon atoms, and R ₃
To R ₁₀ are each independently at least one group selected from the group consisting of a hydrogen atom, a halogen atom, and a monovalent hydrocarbon group having 1 to 6 carbon atoms. ] The above-mentioned optical film represented by the above, and the coating composition is cured by irradiation with active energy rays.

5. The polymer film has the following formula (c)

[0012]

[Chemical 5]

[In the above formula (c), R _{11 to} R ₁₈ are each independently a hydrogen atom, a halogen atom and a carbon number of 1 to
It is at least one group selected from the group consisting of 6 hydrocarbon groups. ] And the following formula (d)

[0014]

[Chemical 6]

[In the above formula (d), R _{19 to} R ₂₆ are each independently a hydrogen atom, a halogen atom and a carbon number of 1 to
6 is at least one group selected from the group consisting of 6 hydrocarbon groups, and X is a hydrocarbon group having 1 to 15 carbon atoms. ] The optical film as described in any one of the above, which is mainly composed of a polycarbonate composed of a repeating unit represented by the formula: and the repeating unit represented by the formula (c) is 0 to 90 mol% of the whole.

6. A refraction consisting of a curable resin obtained by applying a coating composition containing a monomer to at least one surface of a polymer film having a refractive index n ₂ and then curing the coating composition by irradiation with active energy rays and / or heat. A method for producing an optical film having a coating layer having a rate of n ₁ , wherein at least 2 monomers are contained in the coating composition so as to satisfy the following formula (a) | n ₂ −n ₁ | ≦ 0.02 (a). A method for producing an optical film, which comprises selecting the type and controlling the refractive index of the coating layer.

In particular, the coating composition for forming the coat layer contains a mixture of at least two kinds of monomers, and bisphenoxyethanol fluorange acrylate having a high refractive index is used as one of the monomers, and one or more other components. For this, a monomer having a lower refractive index than this was selected at an appropriate time. The refractive index of the coat layer can be freely changed by freely changing the compounding ratio of the two or more monomers, and as a result, the transparency is excellent, and the low refractive index to the high refractive index can be changed. Also in the case of a polymer film, it is possible to provide an optical film with less interference unevenness due to the unevenness of the coating layer thickness.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below.

In the present invention, a particularly important point is that by using a material capable of freely adjusting the refractive index of the coating layer, the refractive index of the polymeric film and the coating layer in the visible light range are brought close to each other as much as possible. The object is to reduce reflection occurring at the interface of the coat layer and interference spots resulting from this, and improve the quality as an optical film. That is,
The refractive index of the coating layer is n ₁ , and the refractive index of the polymer film is n _2.
Then, the coating layer and the polymer film are appropriately selected so that the following formula (a) | n ₂ −n ₁ | ≦ 0.02 (a) is satisfied, and the refractive index is adjusted. When the refractive index of the coating layer and the polymer film is | n ₂ −n ₁ |> 0.02, the difference in refractive index is large, and interference fringes of reflected light due to the thickness unevenness of the coating layer are conspicuous. Therefore, | n ₂ −n ₁ | ≦ 0.0
It is more preferably 1.

The polymer film of the present invention has a total light transmittance of 80% or more, preferably 85% or more, and is excellent in transparency. As such a material, for example, polycarbonate, polyether sulfone, epoxy resin, polyester, poly (meth) acrylate, polystyrene, polyarylate, polyolefin, or any polymer that is transparent in the visible light region can be used. It is not limited. Generally, a polymer film may have birefringence (refractive index anisotropy) due to its manufacturing method or post-treatment such as stretching, but the present invention may be a film having such desired birefringence. . For example, an optical compensation film (for example, a retardation film) or a λ / 4 plate suitable for a liquid crystal display element corresponds to this. Even in such a film, when solvent resistance and scratch resistance are required, the refractive index of the coating layer is N ₁ and the average of the three-dimensional refractive index of the polymer film is the refractive index n ₂ (that is, n ₂ = (n _x +
If n _y + n _z ) / 3) satisfies the above formula (a), an effect of reducing interference spots to some extent can be expected. Here, n _x is the refractive index in the direction of the largest refractive index in the film surface of the polymer film, n _y is the refractive index in the direction orthogonal to the n _x direction in the film surface of the polymer film, and _nz is the film Is the refractive index in the thickness direction. However, for polyethylene terephthalate, polynaphthalene terephthalate, etc., which have a large refractive index, it is difficult to bring the refractive index close to each other only by the coating layer as described below, and therefore metal oxide particles or a polymer containing a metal in the molecule is used in the coating layer. The effect of reducing interference spots can be expected by including them in.

However, when the polymer film of the present invention is used for optical applications, especially for display applications such as liquid crystals, a polymer film having a small birefringence, for example, a retardation at a wavelength of 550 nm of 20 nm or less is desirable. As such a material, for example, polycarbonate, polyether sulfone, polyester, polyester carbonate and the like are desirable. And it is desirable that these are manufactured by the melting method or the casting method. Among them, the casting method, which is excellent in the surface flatness and optical isotropy of the film, is more desirable.

In particular, as a polymer having small optical anisotropy, high heat resistance and capable of being formed into a film by the casting method, the following formula (c) is used.

[0023]

[Chemical 7]

[In the above formula (c), R _{11 to} R ₁₈ are each independently a hydrogen atom, a halogen atom and a carbon number of 1 to
It is at least one selected from monovalent hydrocarbon groups of 6. ] The repeating unit represented by and the following formula (d)

[0025]

[Chemical 8]

[In the above formula (d), R _{19 to} R ₂₆ are each independently a hydrogen atom, a halogen atom and a carbon number of 1 to 1].
Selected from monovalent hydrocarbon groups of 6 and X has 1 to 15 carbon atoms.
Is a hydrocarbon group. ] A polycarbonate composed of a polymer represented by Here, when the composition ratio of the above formula (c) is 0 to 100 mol%, the refractive index is 1.58 to
It takes a relatively large value of 1.64.

In the above formula (c), R _{11 to} R ₁₈ are each independently a hydrogen atom, a halogen atom such as chlorine or bromine,
It is a monovalent hydrocarbon group having 1 to 6 carbon atoms. Examples of such a hydrocarbon group include a methyl group, an ethyl group, an isopropyl group,
Examples thereof include an alkyl group such as a cyclohexyl group and an aryl group such as a phenyl group. Among these, a hydrogen atom and a methyl group are preferable. It is particularly preferable that R ₁₁ or R ₁₃ is a methyl group and R ₁₆ or R ₁₈ is a methyl group.

In the above formula (d), R _{19 to} R ₂₆ are each independently a hydrogen atom, a halogen atom such as chlorine or bromine, or a monovalent hydrocarbon group having 1 to 6 carbon atoms. Examples of such a hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, an isopropyl group and a cyclohexyl group, and an aryl group such as a phenyl group. Among these, a hydrogen atom and a methyl group are preferable. X is a hydrocarbon group having 1 to 15 carbon atoms, and specific examples include the following formula group

[0029]

[Chemical 9]

And the like. Where R ₂₇ to R in X
Each ₃₃ is independently selected from a hydrogen atom, a halogen atom, and a monovalent hydrocarbon group having 1 to 22 carbon atoms, and Ar is at least one group selected from an aryl group having 6 to 10 carbon atoms. Specific examples of R ₂₇ to R ₃₃ are the same as the above R _{11 to} R _26, and specific examples of Ar include a phenyl group and a naphthyl group.

With respect to the proportion of the repeating units represented by the above formulas (c) and (d), the above formula (c) is 0 to 90 mol%, preferably 30 to 8 mol% with respect to the whole polycarbonate.
It is 0 mol%. When the content of the repeating unit represented by the above formula (c) is 10 mol% or more, the glass transition point is 170 ° C.
As described above, the process margin when manufacturing a device as an optical film is expanded. On the contrary, when the repeating unit represented by the above formula (c) is more than 90 mol%, the light transmittance is lowered and the film becomes brittle, which is not preferable.

The thickness of the polymer film in the present invention is usually 20 to 500 μm, and particularly preferably 50 to 400 μm for display applications.

The coat layer in the present invention is formed on at least one surface of the polymer film. The coat layer is made of a curable resin from the viewpoint of improving solvent resistance and scratch resistance. Examples thereof include resins having a three-dimensional crosslinked structure such as (meth) acrylic crosslinked resin, vinyl crosslinked resin, polysiloxane crosslinked resin, and epoxy crosslinked resin. Such a coating layer is formed by coating a coating composition containing a curable resin monomer and an appropriate solvent on the surface of a polymer film by a known coating method, and then irradiating the formed coating film with active energy rays. The reaction occurs and is cured by heating or heating.
Among them, a monomer having an unsaturated double bond such as a (meth) acrylic group or a vinyl group is treated with an ultraviolet ray, a visible ray, an electron beam, an X-ray.
From the viewpoint of productivity, it is preferable to carry out a crosslinking reaction and cure with an active energy ray such as a ray. Among these, acrylic resins having an acrylic group are preferable from the viewpoint of reactivity, and specific examples thereof include epoxy acrylate,
Urethane acrylate, polyester acrylate, silicone acrylate and the like are preferably mentioned, but these are not particularly limited here. Suitable initiators for these compounds (polymerization initiators, photosensitizers, etc.)
Are preferably used in combination, and the initiators may be used alone or in combination of two or more.

The thickness of the coating layer thus formed is from 0.01 μm to 20 μm, preferably 0.03 μm.
It can be appropriately selected from the range of m to 10 μm.

Generally, a refractive index of a crosslinkable resin such as a (meth) acrylic resin, a polysiloxane resin or an epoxy resin is smaller than 1.58. Therefore, polycarbonate is used as a polymer film. When a coating layer made of these crosslinkable resins is applied to the surface, the difference in refractive index between the polymer film and the coating layer becomes large,
The unevenness of the thickness of the coating layer generated during coating becomes conspicuous due to reflection and interference. Therefore, it is preferable to use a material having a refractive index close to that of the polymer film used for the coat layer. At this time, it is desirable that the refractive index of the coat layer and the polymer film be close to each other by containing a component having a similar molecular skeleton used in the polymer film to the molecular skeleton of the monomer used in the coat layer. This is because the refractive index wavelength dependence of the polymer (generally referred to as refractive index wavelength dispersion) and the refractive index wavelength dependence of the coating layer are close to each other, and the effect of being able to reduce the refractive index difference in a wide wavelength range can also be expected. This is because. However, the method of adjusting the refractive index of the coat layer is not necessarily limited to the above.

One feature of the coating layer of the present invention is that the refractive index of the coating layer can be adjusted so that the refractive index of the polymer film and the refractive index of the coating layer are close to each other. For this purpose, at least two kinds of the above-mentioned crosslinkable monomers are appropriately selected, and at least one component has a higher refractive index than the polymer film used and at least one component has a lower refractive index than the polymer film used. Is desirable. At this time, the molecular skeleton used for the polymer film,
It is desirable that the monomer to be used contains a component having a similar molecular skeleton as a method for bringing the refractive index of the polymer film and the refractive index of the coat layer close to each other. This is because the wavelength dependence of the refractive index of the polymer film (generally referred to as wavelength dispersion of the refractive index) and the wavelength dependence of the refractive index of the coating layer are close to each other, and the effect of reducing the refractive index difference in a wide wavelength range can be expected. . However, the method of adjusting the refractive index of the coat layer is not limited to the above. For example, for the purpose of increasing the refractive index of the coating layer, but within a range in which the surface smoothness of the coating layer is lowered or the haze is not increased so much, metal oxide fine particles typified by titanium oxide or zinc oxide are used in combination with the above monomers. However, it is also possible to add it to the coating composition. As a material for increasing the refractive index, a monomer containing an aromatic ring, chlorine, bromine, iodine or sulfur is effective, but a monomer containing a metal such as titanium in the molecule is also effective.

Specific monomers forming the curable resin include, for example, those having a fluorene skeleton in the molecular structure, specifically, the following formula (b):

[0038]

[Chemical 10]

A crosslinkable acrylate monomer represented by
It is particularly preferable to include Above all, in the above formula (b)
And R₁~ R₂Are both ethyl groups having 2 carbon atoms
R ₃~ R_TenIs a hydrogen atom, a crosslinking reaction occurs
The refractive index of the coating layer formed by increasing it to around 1.63
Therefore, the refractive index is higher than that of the above formula (b).
A combination of at least two types of low-crosslinking monomers
Coated layer with an arbitrary refractive index
Can be adjusted.

In this case, the crosslinkable monomer that gives a curable resin having a lower refractive index than the polymer film used is not particularly limited, but other acrylates other than the acrylate monomer represented by the above formula (b), or For example, a material containing a fluorine atom or a silicon atom and having many olefin skeletons or alkyl groups is effective. The crosslinkable monomer that gives a curable resin having a higher refractive index and a lower refractive index than these polymer films is mixed at an appropriate mixing ratio so as to match the refractive index of the polymer film as much as possible, for example, represented by the above formula (b). 1 to 99 mol% of the total monomers to be mixed. However, if the refractive index of the applicable polymer film and the refractive index of the two or more monomers to be blended are relatively close to each other, even if the ratio of the blended monomers is slightly shifted, it does not greatly differ from the target refractive index. It is preferable in terms.

When a bifunctional monomer such as the above formula (b) is used as the crosslinkable monomer having a high refractive index,
Two or more, preferably three or more crosslinking points (acrylic group, etc.) in one molecule in at least one of the other components to be blended.
It is preferable to have the following because solvent resistance and scratch resistance are improved. However, when a monomer having an extremely large number of crosslinking points (for example, one having 10 or more crosslinking points in one molecule) is used in combination with the above formula (b), the more the monomer component having a large number of crosslinking points, the more Although it is possible to improve solvent resistance and scratch resistance, it tends to become brittle. Therefore, when a monomer having a large number of crosslinking points is used in combination, brittleness can be prevented by appropriately using a monomer of the third component having a reduced number of crosslinking points in one molecule.

The polymer film as described above,
And by using the coat layer, there are few interference spots,
An optical film having excellent solvent resistance and scratch resistance can be obtained.

The optical film of the present invention is excellent in transparency, the light transmittance is usually 80% or more, and the haze is usually 3.0.
% Or less, especially when used for display applications represented by liquid crystal display elements, organic EL elements, paper-like displays, and touch panels, the light transmittance is 85%.
As described above, the haze is preferably 1.0% or less.

When the optical film of the present invention is used for the above liquid crystal display device or organic EL device, the optical film is further provided on the optical film according to the use and the purpose, and a transparent conductive layer. Further, a slipping layer, a light reflecting layer, a light absorbing layer, a light diffusing layer and the like can be appropriately added.

[0045]

EFFECTS OF THE INVENTION According to the present invention, by laminating a coating layer having a refractive index extremely close to that of the polymer film on the polymer film, optical interference caused by unevenness in the thickness of the coat layer can be prevented. It is possible to impart functions such as solvent resistance and scratch resistance while reducing the visibility and maintaining excellent visibility as an optical film.

Further, as the monomer used for the coat layer,
Fluorene derivative with high refractive index and at least two kinds of monomer with low refractive index are contained, and by changing the compounding ratio of the monomer, the refractive index can be freely adjusted according to the applicable polymer film. It is possible to

The optical film of the present invention has not only solvent resistance and scratch resistance but also excellent visibility, and can be used in any industry where optical characteristics are important. Among them, the present invention is a liquid crystal display device, an organic EL device.
It can be used as a transparent film substrate for devices, paper-like displays, touch panels, and other displays.

[0048]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Parts and% in the examples are by weight unless otherwise specified. Further, various measurements in the examples were performed as follows. (1) Refractive index: Measurement was performed using a refractometer 2-T manufactured by Atago Co., Ltd. The temperature at the time of measurement was 25 ° C., and the light source was D line 589 nm of a sodium lamp. The coat layer was obtained by coating glass and peeling it off. (2) Interference spot: The interference spot was visually observed under a three-wavelength light type fluorescent lamp. (3) Total light transmittance: COH-30 manufactured by Nippon Denshoku Industries Co., Ltd.
It was measured using 0A. (4) Haze: Measured using COH-300A manufactured by Nippon Denshoku Industries Co., Ltd.

The following abbreviations were used for the compounds shown below. BisA: 2,2-bis (4-hydroxyphenyl) propane BCF: 9,9-bis (4-hydroxy-3-methylphenyl) fluorene ITO: Indium-tin oxide BPEF-A: Bisphenoxyethanol full orange acrylate (Osaka Gas) UA: Urethane acrylate (“NK oligo U-15HA” manufactured by Shin-Nakamura Chemical) DCP-A: Dimethylol tricyclodecane diacrylate (“Light acrylate DCP- manufactured by Kyoeisha Chemical”)
A ")

Example 1 Average molecular weight 3 in which bisphenol component is BisA / BCF = 70/30 in molar ratio
A polycarbonate resin having a Tg of 193 ° C. at 7,000 was dissolved in methylene chloride so as to be 20% by weight. Then, the liquid was cast on a polyester film having a thickness of 175 μm by a die coating method. Then, it was dried in a drying oven until the residual solvent concentration reached 13% by weight, and peeled from the polyester film. Then, the polycarbonate film obtained was kept in a drying oven at 180 ° C. in such a manner that the vertical and horizontal tensions did not differ as much as possible and the tension balance was kept to a minimum to maintain the film, while the residual solvent concentration of the film was almost 0. It was dried to 0.3% by weight and adjusted to have a thickness of 120 μm. The total light transmittance was 90.4%.

One side of the polymer film thus obtained is coated with a coating composition serving as a coat layer,
After drying at 60 ° C. for 30 seconds, ultraviolet rays having an integrated light amount of 700 mJ / cm ² were irradiated by a high pressure mercury lamp having an intensity of 160 w to form a film having a thickness of 4 μm. The coating composition for the coat layer was BPEF-A: 390 parts by weight, U
A: 110 parts by weight, toluene as diluent solvent: 1150
By weight, IGAGACURE 184: 15 parts by weight of Ciba-Geigy as a photoinitiator, and SH28PA: 0.18 parts by weight of Toray Dow Corning as a leveling agent were sequentially added and stirred until uniform.

As shown in Table 1, the finished optical film had no interference spots, a high light transmittance, a low haze, and showed good characteristics as an optical film.

Example 2 Bisphenol is Bis
A / BCF = 50/50 (molar ratio), a polymer film having a thickness of 120 μm, which is composed of a polycarbonate copolymer having a Tg of 211 ° C., and two coating compositions used for the coating layer are BPEF-A: An optical film was produced in the same manner as in Example 1 except that the content was changed to 460 parts by weight and UA: 40 parts by weight. Total light transmittance is 9
It was 0.9%.

As shown in Table 1, the finished optical film had no interference spots, a high light transmittance and a low haze, and showed good characteristics as an optical film.

[Example 3] Bisphenol component is Bis
A = 100 μm, a polymer film having a Tg of 155 ° C. and a thickness of 120 μm, a total light transmittance of 91.3%, and two coating compositions used for the coating layers, BPEF- A: 30
An optical film was produced in the same manner as in Example 1 except that the amount was changed to 4.5 parts by weight and UA: 195.5 parts by weight.

As shown in Table 1, the finished optical film had no interference spots, a high light transmittance and a low haze, and showed good characteristics as an optical film.

Example 4 Bisphenol component is Bis
A = 42 mol% and 3,3,5-trimethyl-1,1-di (4-phenol) cyclohexylidene = 58 mol% polycarbonate copolymer (APEC-H manufactured by Bayer AG)
T9371, Tg = 205 ° C.), a polymer film having a thickness of 120 μm was used, and the total light transmittance was 91.3%.
BPEF-A: 205 parts by weight, UA: 295
An optical film was produced in the same manner as in Example 1 except that the amount was changed to parts by weight.

As shown in Table 1, the finished optical film had no interference spots, a high light transmittance, a low haze, and showed good characteristics as an optical film.

Comparative Example 1 BPFE-A of the coating composition used for the coating layer in Example 2 was replaced with DCP-
A: An optical film was produced in the same manner as in Example 2 except that 375 parts by weight and UA were changed to 125 parts by weight.

As shown in Table 1, the finished optical film was excellent in total light transmittance and haze, but had poor visibility due to interference spots.

[0061]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C08L 69:00 G02B 1/10 Z (72) Inventor Saito Tokken 4-3 Asahigaoka, Hino-shi, Tokyo No. 2 Inside the Tokyo Research Center, Teijin Ltd. (72) Inventor Hiroshi Hara 4-chome, Asahigaoka, Hino-shi, Tokyo No. 2 Inside the Tokyo Research Center, Teijin Limited (72) Toshiaki Yatabe 4-chome, Asahigaoka, Hino-shi, Tokyo Ban No. 2 Teijin Ltd. of Tokyo research Center in the F-term (reference) 2K009 AA15 BB24 CC24 DD05 4F006 AA36 AB43 CA05 EA03 4F100 AK01A AK01B AK01C AK03A AK12A AK25A AK41A AK45A AK53A AK54A AL05B AL05C BA02 BA03 BA06 BA10A BA10C BA15 CC00B CC00C GB41 JB07 JB12B JB12C JB14B JB14C JK14 JN01 JN01A JN18B JN18C YY00 YY00B YY00C 4J100 AL66P BA02 BC43 BC48 CA01 CA03 JA32

Claims (6)

[Claims] 1. An optical film having a coating layer made of a curable resin and having a film thickness of 0.01 μm to 20 μm on at least one side of a polymer film having a total light transmittance of 80% or more, The refractive index of the coat layer is n ₁ ,
An optical film satisfying the following formula (a), where n ₂ is the refractive index of the polymer film. │n ₂ −n ₁ │ ≦ 0.02 (a) (In the above formula, the refractive indices n ₁ and n ₂ are 25 ° C., sodium D
(Measure at line wavelength 589 nm) 2. The coating layer comprises a coating composition containing a monomer having a fluorene skeleton in its molecular structure, coated on at least one side of a polymer film, and then a curable resin produced by irradiation with active energy rays and / or heat. The optical film according to claim 1, which is 3. The coating layer is formed by coating a coating composition containing at least two kinds of monomers having different refractive indexes on at least one surface of a polymer film, and then curing the resin by irradiation with active energy rays and / or heat. The optical film according to claim 1 or 2, wherein 4. The monomer has the following formula (b): [In the above formula (b), R _{1 to} R ₂ are each independently a divalent hydrocarbon group having 2 to 6 carbon atoms, and R _{3 to} R ₁₀ are each independently a hydrogen atom, a halogen atom and a carbon number 1 to 1]. 6
Which is at least one group selected from the group consisting of monovalent hydrocarbon groups. ] The optical film of Claim 2 or 3 which has a fluorene skeleton in the molecular structure represented by these, and is hardened | cured by active energy ray irradiation. 5. The polymer film has the following formula (c): [In the above formula (c), R _{11 to} R ₁₈ are each independently at least one group selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group having 1 to 6 carbon atoms. ] And a repeating unit represented by the following formula (d): [In the formula (d), R _{19 to} R ₂₆ are each independently at least one group selected from the group consisting of a hydrogen atom, a halogen atom, and a monovalent hydrocarbon group having 1 to 6 carbon atoms, and X is It is a hydrocarbon group having 1 to 15 carbon atoms. ] The optical film according to any one of claims 1 to 4, which is mainly composed of a polycarbonate composed of a repeating unit represented by the formula: and the repeating unit represented by the formula (c) is 0 to 90 mol% of the whole. . 6. A cured product obtained by applying a coating composition containing a monomer to at least one surface of a polymer film having a refractive index n ₂ and then curing the coating composition by irradiation with active energy rays and / or heat. A method for producing an optical film having a coat layer of a refractive index n _{1 made of} an organic resin, wherein the coating composition comprises the following formula (a) | n ₂ −n ₁ | ≦ 0.02 (a): 2. A method for producing an optical film, which comprises selecting at least two kinds of the above monomers and controlling the refractive index of the coat layer.