JP2005178173A - Plastic film, functional film, and image display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film which suppresses interference spots and is excellent in physical strength and weatherability. <P>SOLUTION: In the plastic film, a layer which directly adjoins at one surface of a transparent support and contains fine inorganic particles containing titanium dioxide as a main component and at least one element selected from cobalt, aluminum, and zirconium is formed, and haze is 5.0% or below. A functional film having a functional layer is prorided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a functional film that prevents interference spots and has excellent weather resistance. The present invention also relates to an image display device provided with a functional film that prevents interference spots and has excellent weather resistance.

In recent years, transparent plastic supports have been applied to plastic products, plastic surface displays such as LCDs, display panels for mobile phones and portable games, touch panels, etc. to impart scratch resistance, and glass products, glass such as CRT and PDP. Demand is growing as a support for hard coat films, antireflection films and the like for imparting functions such as anti-scattering, antireflection, and antifouling properties to display surfaces.
Among them, polyester resin-based films, particularly polyethylene terephthalate (PET) biaxially stretched films have excellent mechanical properties, flame resistance, chemical resistance, etc., and therefore are in demand as functional film support films. The growth is remarkable.

  In the case of forming a functional plastic film using these transparent plastic supports, a functional layer of several μm to 50 μm composed of an organic compound resin is often formed directly on the support or through a thin easy-adhesive layer, etc. For example, a hardened layer such as a hard coat layer is formed. The refractive index (plane direction) of the PET film is about 1.65, whereas the refractive index of the hard coat layer formed of an organic compound such as an acrylic resin is usually 1.50 to 1.56 centering on 1.53. Yes, there is a refractive index difference of 0.10 or more. For this reason, the functional film of which the support is PET has (i) a high reflectance at the interface, (ii) interference spots occur due to the interference between the reflected light at the interface and the reflected light at the surface, (iii) There is a problem that interference spots occur due to interference of reflected light on the front and back surfaces of the PET. From these three problems (i), (ii), and (iii), articles such as bonded image display devices It degrades the visibility and impairs the sense of quality.

  In particular, under a three-wavelength fluorescent lamp, interference spots are emphasized because the ratio of the emission line spectral component is high. In recent years, the spread of three-wavelength fluorescent lamps has been rapidly progressing in ordinary households, and the problem of interference spots has become important. Therefore, the use application of the functional plastic film using the PET film as a support is remarkably limited. Otherwise, functional films are being sent out to the world with the problem of interference spots. In fact, in the field of large flat televisions where PET film is used as a support, interference spots are observed in most of the antireflection films currently mounted.

  Interference spots occur due to subtle film thickness unevenness of a hardened layer such as a hard coat layer of about several μm to 50 μm or an adhesive layer formed on the support. The solution to this problem of film thickness unevenness is fundamentally different from, for example, a hard coat layer of a synthetic resin lens, which is formed by a film forming method with little coating unevenness, such as an immersion method or a vapor deposition method. Usually, in a plastic film and a functional film produced by a roll film having a width of 30 cm or more and a length of 10 m or more, it is not possible to eliminate subtle coating unevenness that occurs randomly in the conventional coating method.

  For the purpose of preventing such interference spots, focusing on making the refractive index of the hard coat layer close to the refractive index of the PET film, an ionizing radiation curable resin containing metal oxide ultrafine particles having a high refractive index is used. A method of forming a hard coat layer by applying and curing on a high refractive index film such as a film, or a method of laminating an intermediate refractive index layer between a hard coat layer and a PET film and changing the refractive index stepwise. It has been proposed (see, for example, Patent Document 1). Thus, since the refractive index of a PET film is as high as 1.65, a layer having a high refractive index adjacent to the PET film (hereinafter referred to as a support-adjacent high refractive index layer) is required.

The high refractive index layer adjacent to the support can also be formed using a resin having a high refractive index, but it is more preferable to prepare by dispersing fine particles of inorganic fine particles having a high refractive index into the film. Simple and preferred. A transparent high refractive index layer having a higher refractive index can be formed by introducing more inorganic fine particles having a high refractive index into the film while maintaining a fine dispersion state (for example, Patent Documents). 2-8). For this reason, it is very effective to introduce titanium dioxide fine particles having an extremely high refractive index into the high refractive index layer adjacent to the support.
However, the titanium dioxide fine particles have a photocatalytic action. When a functional film having a high refractive index layer adjacent to the support is used under sunlight for a long time, the photocatalytic action causes the high refractive index layer adjacent to the support. The organic compound contained in is decomposed, and the physical strength and optical performance of the functional film are significantly deteriorated. Such a phenomenon occurs particularly remarkably in the high refractive index layer adjacent to the support in which the titanium dioxide fine particles are kept in a finely dispersed state. In particular, in a functional film in which a functional layer such as a hard coat layer having a thickness of 2 μm or more is further laminated directly or via another layer on the support adjacent high refractive index layer, the support adjacent high refractive index layer is When the titanium dioxide fine particles are destroyed by the photocatalytic action, the functional layer of 2 μm or more is also peeled off at the same time, not only losing the function, but also damaging the appearance.
Therefore, there is a demand for a functional film that can be produced by coating, contains titanium dioxide fine particles, and has a support-adjacent high refractive index layer that is excellent in weather resistance (particularly light resistance). No fully satisfactory functional film is provided.
JP 2000-111706 A JP-A-8-110401 JP-A-8-179123 JP-A-11-153703 JP 2001-166104 A JP 2001-188104 A JP 2002-116323 A JP 2002-156508 A

In view of the above situation, the object of the present invention is to suppress interference spots in a plastic film or functional film having a layer containing titanium dioxide fine particles directly adjacent to a support, and is excellent in physical strength and weather resistance. Is to provide a good film.
Another object of the present invention is to provide a functional film that is inexpensive and can be mass-produced, suppresses interference spots, and has excellent physical strength and weather resistance.
Still another object of the present invention is to provide a functional film having various functionalities, particularly an antireflection film having a low reflectance, and further provide an image display device provided with the functional film. There is.

  As a result of intensive studies, the present inventors have used titanium dioxide fine particles in order to optimize the refractive index of the layer adjacent to the transparent support, and by optimizing the elemental composition of the titanium dioxide fine particles, It was found that mass production is possible, interference spots are suppressed, and a film excellent in physical strength and weather resistance can be provided.

Specifically, it has been found that the above problem can be achieved by the following means.
1. Directly adjacent to at least one surface on a transparent support, having a layer containing inorganic fine particles containing titanium dioxide as a main component and containing at least one element selected from cobalt, aluminum and zirconium, and having a haze of 5.0% A plastic film characterized by:
2. 2. The plastic film as described in 1 above, wherein the inorganic fine particles contain at least cobalt.
3. 3. The plastic film as described in 2 above, wherein the content (mass ratio) of cobalt to titanium is 1% or more.
4). 4. The plastic film as described in any one of 1 to 3 above, wherein the layer containing the inorganic fine particles contains an organic compound binder.

5). 5. The plastic film according to any one of 1 to 4, wherein at least one functional layer having a thickness of 2 μm or more is laminated on at least one surface of the transparent support.
6). 6. The functional film as described in 5 above, wherein the layer containing the inorganic fine particles is the functional layer.

7). 6. The functional film as described in 5 above, wherein the functional layer is laminated on the layer containing the inorganic fine particles directly or via another layer.
8). 8. The functional film as described in any one of 5 to 7 above, wherein the transmittance of all layers laminated on the layer containing the inorganic fine particles with respect to a wavelength of 380 nm is 50% or more.
9. 9. The functional film as described in 7 or 8 above, wherein the refractive index n _S of the transparent support and the refractive index n _H of at least one of the functional layers satisfy the following formula (1).
Formula (1): 0.03 ≦ | n _S −n _H |
10. 9. The functional film as described in 7 or 8 above, wherein the refractive index n _S of the transparent support and the refractive index n _H of at least one of the functional layers satisfy the following formula (11).
Formula (11): 0.06 ≦ | n _S −n _H |
11. 9. The functional film as described in 7 or 8 above, wherein the refractive index n _S of the transparent support and the refractive index n _H of at least one of the functional layers satisfy the following formula (12).
Formula (12): 0.10 ≦ | n _S −n _H |

12 The functional film as described in any one of 9 to 11 above, further comprising a primer layer including a layer containing at least the inorganic fine particles between the transparent support and the functional layer.
13. 13. The functional film as described in 12 above, wherein the refractive index n _S of the transparent support, the refractive index n _H of the functional layer, and the refractive index n _{P of the} primer layer satisfy the following formula (2).
Formula (2)

14 13. The functional film as described in 12 above, wherein the refractive index n _S of the transparent support, the refractive index n _H of the functional layer, and the refractive index n _{P of the} primer layer satisfy the following formula (4).
Formula (4)

15. The functional film according to the above 13 or 14, wherein the refractive index n _P and the film thickness d _{P of the} primer layer satisfy the following formula (3).
Formula (3) d _P = (2N−1) × λ / (4n _P )
In Formula (3), λ is a wavelength of visible light and is any value in the range of 450 nm to 650 nm, and N is a natural number.
16. 16. The functional film as described in 15 above, wherein N = 1 or N = 2.
17. 16. The functional film as described in 15 above, wherein N = 1.
18. λ is the functional film according to any one of the above 15 to 17, wherein λ is a wavelength of visible light and is any value in the range of 500 nm to 600 nm.
19. The functional film according to any one of 15 to 17 above, wherein λ is a wavelength of visible light and is any value within a range of 530 nm to 580 nm.

20. 20. The hard coat film as described in any one of 5 to 19 above, wherein the functional layer is a hard coat layer.
21. 21. The hard coat film as described in 20 above, wherein the surface has a pencil hardness of H or more.
22. The functional film according to any one of 5 to 21, wherein the total thickness of the functional layers is 5 μm or more.
23. The functional film as described in any one of 5 to 21 above, wherein the total thickness of the functional layers is 15 μm or more.

24. 24. The functional film as described in any one of 5 to 23 above, wherein the transparent support is a transparent plastic film.
25. 25. The functional film as described in 24 above, wherein the transparent support is a polyethylene terephthalate (PET) film.
26. 25. The functional film as described in 24 above, wherein the transparent support is a triacetyl cellulose (TAC) film.
27. 25. The functional film as described in 24 above, wherein the transparent support is a polycarbonate (PC) film.

28. 5. The antireflection film, wherein the plastic film according to any one of 1 to 4 or the functional film according to 5 to 27 has an antireflection layer.
29. At least one layer of the antireflection layer is a layer containing inorganic fine particles containing titanium dioxide as a main component and containing at least one element selected from cobalt, aluminum and zirconium, and an organic compound binder. 29. An antireflection film according to 28.
30. 30. The antireflection film as described in 29 above, wherein the inorganic fine particles contain an element selected from cobalt, aluminum and zirconium.
31. 31. The antireflection film as described in 29 or 30 above, wherein the inorganic fine particles contain at least cobalt.
32. 32. The antireflection film as described in any one of 28 to 31, wherein the antireflection layer has a surface reflectance of 3% or less.
33. 32. The antireflection film as described in any one of 28 to 31, wherein the antireflection layer has a surface reflectance of 1.5% or less.

34. 34. The functional film with the pressure-sensitive adhesive layer according to the above 28-33, wherein the pressure-sensitive adhesive layer is laminated directly or via another layer on the transparent support.
35. A layer containing inorganic fine particles containing titanium dioxide as a main component and containing at least one element selected from cobalt, aluminum, and zirconium and an organic compound binder is laminated between the support and the pressure-sensitive adhesive layer. The functional film with an adhesive layer according to 34 above.
36. 34. The functional film with an adhesive as described in 33 above, wherein the transmittance of the functional film at a wavelength of 380 nm is 50% or more.

37. 37. An image display device comprising the functional film according to any one of 34 to 36 above.

  According to the present invention, it is possible to provide a plastic film and a functional film having a layer containing specific titanium dioxide fine particles directly adjacent to a support and having excellent physical strength and weather resistance. The film of the present invention can also suppress interference spots by adjusting the reflectance at the interface between the constituent layers of the film using a layer containing titanium dioxide fine particles. Furthermore, since it can be manufactured by coating, it is inexpensive and can be mass-produced. In addition, the functional layer can be provided with various functions, and a functional film having various functionalities, in particular, an antireflection film having low reflectivity and excellent physical strength and weather resistance can be provided. . These various functional films are suitable for improving various performances such as the visibility of the display image of the image display device and the scratch resistance of the display surface.

Details of the present invention will be described below. In the present specification, the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”.
[Interference spots]
The interference spots taken up in the present invention include, for example, a layer having a large refractive index difference between a hard coat layer, an adhesive layer and the support on a high refractive index support film typified by PET (polyethylene terephthalate). When it is provided, the reflectance at the interface between the layer and the support becomes high, and it is generated by interference between the reflected light from the interface and the reflected light from the film surface. The interference is affected by a subtle film thickness change of the layer such as the hard coat layer provided on the support or the support, and generates spots (unevenness) that are observed in stripes or spots. Although this phenomenon is expressed as interference fringes and Newton rings depending on published patents and literatures, the appearance of unevenness caused by the same mechanism is not necessarily striped or ring-shaped, and the film thickness is particularly thin (several If there is a (μm or less) layer, it may be observed as a mottled pattern. In the present invention, based on this situation, it is expressed as interference spots.

  The interference spots taken up in the present invention are strongly observed when a low refractive index support film typified by TAC (triacetyl cellulose) is used as a support when combined with a hard coat layer having a high refractive index. The

When such interference spots occur, the refractive index difference (absolute value) between the layer provided on the support and the support is usually 0, as described in JP-A-7-15902. It is supposed to occur when there is 03 or more.
Therefore, the present invention described below has a remarkable effect of preventing interference spots when the difference between the refractive index of the functional layer such as the hard coat layer and the pressure-sensitive adhesive layer and the refractive index of the support is 0.03 or more. appear. The effect is greater when the difference in refractive index is 0.06 or more, and the effect is greater when it is 0.10 or more.

  It is well known that the distance at which light can interfere, that is, the coherent length (coherence distance), is approximately determined by the wavelength and bandwidth (emission spectrum width) of light and is expressed by the following equation (for example, JDRancourt, “OPTICAL THIN FILMS USER HANDBOOK” Optical Coating Laboratory, Inc. 11 (1996)).

Coherent length L = λ ² / Δλ (Δλ: bandwidth)

  From this equation, light from a light source including a spectrum having a narrow bandwidth Δλ has a long coherence length, so that interference spots are likely to be observed, and a fluorescent lamp including an emission line spectrum having a narrow bandwidth due to emission of mercury atoms due to discharge. Interference spots are observed below, and it can be understood that the interference spots are particularly strong under a light source having a high emission spectrum component ratio with a narrow bandwidth, for example, a three-wavelength fluorescent lamp.

On the other hand, for example, when the hard coat layer is a functional layer and the interference between the reflected light from the hard coat layer / support interface and the reflected light from the hard coat layer surface is considered, the thickness of the hard coat layer is coherent. Since it can be said that interference is likely to occur when the length is shorter than the length, it is understood that interference spots appear strongly in a hard coat film having a film thickness of about 5 μm and a relatively thin hard coat layer. However, since the emission spectrum of the three-wavelength fluorescent lamp includes an emission line spectrum (such as 546.074 nm) with a very narrow bandwidth due to the emission of mercury atoms, the interference spots become strong as described above. Interference spots are also observed in the coat layer.
Therefore, as a method of eliminating the interference spots, the thickness of the hard coat layer is increased to 20 μm or more to reduce the interference spots, and the reflectance of the hard coat layer and the support is further lowered to reduce the reflected light itself. By doing so, a method of completely eliminating the interference spots can be considered.

  The essential solution to this interference spot is to reduce the reflectivity of the functional layer / support interface and reduce the reflected light from the interface, preferably eliminating it from the surface of the functional layer. It is to prevent interference with the reflected light. This is effective for functional layers that cause interference spots, particularly for layers in which the value of the refractive index that affects the reflectance is not normally considered, such as hard coat layers and pressure-sensitive adhesive layers. / Reducing the reflectance from the interface with the support leads to the solution of interference spots.

  In the present invention, as a method for solving interference spots, a method of providing a layer containing titanium dioxide fine particles having a specific composition directly adjacent to a support can be used. That is, as one method of preventing interference spots, a method of eliminating the refractive index difference between the functional layer and the transparent support by incorporating titanium dioxide fine particles in the functional layer and making the functional layer adjacent to the support. Is mentioned. As another method, a primer layer containing titanium dioxide fine particles and including a layer adjacent to the support is provided at the interface between the transparent support and the functional layer, and physical properties such as refractive index and reflectance of each layer are provided. By optimizing the above, there is a method of reducing the reflectance at this interface and preventing the occurrence of interference spots. Since the functional film of the present invention uses fine titanium dioxide particles having a specific composition, interference spots are prevented and physical strength and weather resistance are also excellent.

Hereinafter, the functional film of the present invention will be described in detail.
[Transparent support]
The transparent support used in the present invention is preferably a transparent plastic support. A film shape, a sheet shape, or a plate shape is preferable. The “film” referred to in the present invention includes not only a film shape but also a sheet shape or plate shape as a support.

  When the functional film of the present invention is used as, for example, a hard coat film having a hard coat layer as a functional layer, the refractive index of the hard coat layer formed of a curable organic compound is usually around 1.53. It is preferable to use a support having a high refractive index (1.56 or more). In this case, the refractive index of the support is preferably 1.56 or more and less than 1.90, and more preferably 1.60 or more and less than 1.70. A plastic film formed from a polymer having a high refractive index is preferable. Examples of the polymer having a high refractive index include polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, Polyethylene-1,2-diphenoxyethane-4,4′-dicarboxylate, polybutylene terephthalate) polysulfone, polyarylate and polystyrene (eg, syndiotactic polystyrene). Of these, polycarbonate and polyethylene terephthalate are preferable in terms of availability, and polyethylene terephthalate is particularly preferable in terms of cost.

  In addition, when using a low refractive index hard coat layer having a refractive index lower than usual, it is preferable to use the above-mentioned support having a high refractive index. The refractive index difference is larger than the above.

  In addition, when a high refractive index hard coat layer having a higher refractive index than usual is used, a support having a low refractive index (1.50 or less) may be used. A plastic film formed from a low polymer is preferred. Examples of the polymer having a low refractive index include cellulose acylate (cellulose acetate (eg, triacetylcellulose, cellulose acetate butyrate, cellulose acetate propionate), cellulose tripropionate, cellulose tributyrate), PMMA (polymethyl methacrylate). , PP (polypropylene), and fluorine resin films such as FEP (tetrafluoroethylene-hexafluoropropylene polymer). Of these, triacetyl cellulose is preferable in view of availability.

  “Transparent” of the transparent support means that the light transmittance in the visible light region is 80% or more, and preferably 86% or more. However, when the functional film with the pressure-sensitive adhesive layer is used as a sticker or the like, there may be a printing layer between the primer layer and the pressure-sensitive adhesive layer, and the light transmittance may partially be 80% or less.

The plastic film of the present invention has a haze of 5.0% or less from the viewpoint of visibility. The haze is preferably 3.0% or less, more preferably 2.0% or less, and particularly preferably 1.0% or less. The haze of the transparent support itself is preferably 50% or less, more preferably 25% or less, and particularly preferably 10% or less. However, since it is required to have low haze particularly in applications where linear transmitted light is important, it is preferably 3.0% or less, more preferably 2.0% or less, and 1.0% or less. It is particularly preferred that
The lower limit of the haze is preferably 0%, but is suitably 0.01% from the viewpoint of measurement and the like.

When the support is in the form of a film, the thickness of the support is preferably 20 to 300 μm, and more preferably 80 to 200 μm. When the thickness of the support film is too thin, the film strength is weak, and when it is thick, the rigidity becomes too large. In the case of a sheet, the thickness of the support may be in a range that does not impair the transparency, and those having a thickness of 300 μm to several mm can be used.
When the thickness of the support is 1 mm or less, particularly 300 μm or less, interference spots may be seen due to interference between reflected light on the support surface and the back surface under a light source containing a bright line component in the visible light region, for example, a three-wavelength fluorescent lamp. In this case, in the present invention, the interference spots on the front and back surfaces of the support can be reduced by providing the primer layer containing the titanium dioxide fine particles described above on both sides. In general, a synthetic resin lens has a large thickness, and interference spots due to reflected light on the front and back surfaces do not occur. This is the fundamental difference between synthetic resin lenses and films.

  In the present invention, as described above, by providing a primer layer at the interface between the functional layer such as the hard coat layer and the pressure-sensitive adhesive layer and the support, the reflectance at the interface is greatly reduced, and interference spots are hardly visible. Can be eliminated.

In the primer layer, interference spots occur when the difference between the refractive index n _S of the support and the refractive index n _H of the functional layer is 0.03 or more, and a countermeasure effect appears. The effect is greater when the difference in refractive index is 0.06 or more, and the effect is greater when it is 0.10 or more.

When the refractive index n _P of the primer layer satisfies the following formula (2), the reflectance at the functional layer / support interface can be reduced, and interference spots can be suppressed.
Formula (2)

Furthermore, in order to reduce the reflectance at the hard coat layer / support interface, the refractive index n _P preferably satisfies the following formula (7).
Formula (7)

Furthermore, when the refractive index n _P satisfies the following formula (9), the reflectance can be made to be zero in calculation with the control of the thickness d _p of the primer layer for the line spectrum of a specific wavelength. Is very preferable.
Formula (9)

Furthermore, when the film thickness d _{P is set} to a specific value (formula (3)), the reflectance at the interface can be greatly reduced, and the effect of suppressing interference spots can be enhanced.

Formula (3) d _P = (2N−1) × λ / (4n _P )

  In Formula (3), λ is a wavelength of visible light and any value in the range of 450 nm to 650 nm, and N represents a natural number.

Here, formulas (9) and (3) are described in general optical textbooks (for example, JDRancourt, “OPTICAL THIN FILMS USER HANDBOOK” Optical Coating Laboratory, Inc. 9). 1996)), if the refractive index n _P and the film thickness d _P satisfy both equations, the reflectivity is theoretically completely zero. However, in practice, even if there is a slight deviation from Equation (9) and Equation (3), the reflectance is extremely small and interference spots are not actually recognized. In the present invention, an allowable range of the deviation was found. Specifically, the formula (2) and the formula (7) give a width to the formula (9) and define an allowable range of the deviation.
Equation (7) shows that when a primer layer and a functional layer having a refractive index of 1.53 are laminated on a PET film having a refractive index of 1.65, the reflectance at the interface shows no interference spots. | N _S −n _H | = A width equivalent to 0.03. Formula (2) has a double width.

The thinner the primer layer thickness d _p , the greater the antireflection effect, and the thinner the primer layer, from the viewpoint of mechanical strength. Therefore, for these two reasons, N ≦ 2 (d _P = λ / (4n _P ) or d _P = 3λ / (4n _P )) is preferable, and N = 1 (d _P = λ / (4n _P )) ) Is more preferable.

Furthermore, human eyes have high green visibility (viscosity peak is at 550 nm: JIS-R-3106), and the emission line component of the three-wavelength fluorescent lamp is concentrated around 545 nm. Then, λ is preferably any value in the range of 500 nm to 600 nm, and more preferably any value in the range of 530 nm to 580 nm.
In addition, a film thickness design of λ = 546 nm is also preferable in which the emission line of the fluorescent lamp is aimed at the 546.074 nm (green) emission line. Even in this case, the average reflectance of the interface with respect to the entire visible light area is reduced to about 10% as compared with the case without the primer layer, and the reflectance is reduced to about 1.5% in the visibility weighted average. There is a sufficient anti-reflective effect.

  The present invention is not limited to a functional film used under a fluorescent lamp including a three-wavelength fluorescent lamp. The present invention can be applied to any light source as long as it includes a bright line component in the visible light range. For example, if the light source of the usage environment is a functional film limited to a sodium lamp, a film thickness design of λ = 589 nm can be performed.

As a specific example that satisfies the above formula, for example, when a hard coat film is taken as an example, when the support is PET and the refractive index of the hard coat layer is about 1.53, the following refractive index and film thickness: A primer layer having is preferred.
(E) Refractive index is 1.58 or more and 1.60 or less.
(F) The film thickness is 74 nm to 98 nm or 222 nm to 294 nm.

Moreover, when the refractive index of the support is TAC lower than that of the hard coat layer and the refractive index of the hard coat layer is about 1.60, a primer layer having the following refractive index and film thickness is preferable.
(G) Refractive index is 1.49 or more and 1.51 or less.
(H) The film thickness is 78 nm to 104 nm or 235 nm to 312 nm.

When the functional film of the present invention, for example, a hard coat film is bonded to an image display device or the like, usually, a pressure-sensitive adhesive layer is provided on the side of the support opposite to the side on which the hard coat layer is provided, and the pressure-sensitive adhesive layer Paste through.
In this case, at the interface between the pressure-sensitive adhesive layer and the support, a specific refractive index n _Q and a film having the same relationship as the primer layer with respect to the refractive index n _A of the pressure-sensitive adhesive layer and the refractive index n _{S of the} support. providing a primer layer having a thickness d _Q is, it is possible to reduce the reflectivity at the interface, preferably.

In addition, when the support does not have a specific functional layer such as a hard coat layer, or when the refractive index difference between the functional layer and the support is 0.03 or less, the support Similar problems occur between the adhesive layers. That is, as described above, when the refractive index difference between the support and the pressure-sensitive adhesive layer is 0.03 or more, the reflectance at the interface between the pressure-sensitive adhesive layer and the support is high, and interference spots occur.
In the functional film with the pressure-sensitive adhesive layer of the present invention, the same primer layer as described above is provided between the support and the pressure-sensitive adhesive layer, the reflectance at the interface between the support and the pressure-sensitive adhesive layer is suppressed, and interference spots are reduced. It is a film.

Various pressure-sensitive adhesives usually have a refractive index of about 1.40 to 1.70. An acrylic material having a refractive index of 1.50 to 1.55 is mainly used for pasting the transparent film as in the present invention, but the refractive index n of the adhesive is not limited by this refractive index range. By adjusting the refractive index (n _M ) of the material of the surface of the object (for example, an image display device) to which _{A is} to be attached, the reflectance of the hard coat and the adhesive is suppressed, and further the adhesive and the adhesive are applied. The reflectivity at the interface of the wearing object can be minimized. In recent years, pressure-sensitive adhesives or adhesives with various refractive indexes have been developed (for example, Fumio Ide et al., Optical Transparent Resin, Technical Information Association, 177-180 (2001)). When combined with, the applicable range is extremely wide.

The refractive index difference | n _A −n _M | between the pressure-sensitive adhesive layer provided on the functional film of the present invention and the material of the object to be bonded is preferably | n _A −n _M | ≦ 0.03 or less. _A −n _M | ≦ 0.02 or less is more preferable, and | n _A −n _M | ≦ 0.01 is particularly preferable. Further, the above-mentioned | n _S -n _H | if and similarly | n _S -n _A | accordance increases, the reflectivity of the adhesive interface and the support is increased, | n _S -n _A | is The larger the effect, the greater the effect of the present invention. Therefore, | n _S −n _A | ≧ 0.03 is preferable, | n _S −n _A | ≧ 0.06 is more preferable, and | n _S −n _A | ≧ 0.10 is particularly preferable.

  When primer layers are formed on both surfaces of the same support, each primer layer can be formed of a separate composition depending on the purpose. For example, when the refractive index of the hard coat layer and the pressure-sensitive adhesive layer required for the above reasons are different, the composition design can be performed according to the refractive index. On the other hand, it is also a preferred embodiment that the same composition is formed from the viewpoint of productivity. It is a feature of the present invention for films that the primer layers on the front and back sides can select a unique composition. For example, in the case of a synthetic resin lens, since the required qualities of the primer layer and the hard coat layer are exactly the same on the front and back surfaces, they are usually formed by the dipping method with the same composition and the same film thickness. This is the decisive difference between the functional film of the present invention and the synthetic resin lens.

  When a polyester film is used as a support, the polyester film has high surface cohesiveness due to crystal orientation and poor adhesion to various materials. For the purpose of improving the adhesion between the polyester film and the functional layer, one or both sides of the polyester film can be subjected to a surface treatment by an oxidation method, an unevenness method, or the like as desired. Examples of the oxidation method include corona discharge treatment, glow discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and the like.

[Inorganic fine particles mainly composed of titanium dioxide]
The functional film of the present invention has a layer containing inorganic fine particles containing titanium dioxide as a main component and containing at least one element selected from cobalt, aluminum and zirconium. Here, the main component means a component having the largest content (mass%) among the components constituting the particles.
The refractive index of the layer containing inorganic fine particles mainly composed of titanium dioxide is preferably 1.55 to 2.40. The layer containing inorganic fine particles mainly composed of titanium dioxide of the present invention is adjacent to the support, but preferably has high physical strength. When a large amount of inorganic fine particles is contained, the refractive index of the layer is increased but the physical strength is weakened. Therefore, it is more preferable to suppress the content of the inorganic fine particles and to set the refractive index to a relatively low refractive index of 1.55 to 2.00. Further, 1.55 to 1.70 is particularly preferable. In the following specification, this layer is also referred to as a high refractive index layer of the present invention.

The inorganic fine particles mainly composed of titanium dioxide in the present invention preferably have a refractive index of 1.90 to 2.80, more preferably 2.10 to 2.80, and 2.20 to 2.80. 80 is most preferred.
The mass average diameter of primary particles of inorganic fine particles mainly composed of titanium dioxide is preferably 1 to 200 nm, more preferably 1 to 150 nm, still more preferably 1 to 100 nm, and particularly preferably 1 to 80 nm.

The particle diameter of the inorganic fine particles can be measured by a light scattering method or an electron micrograph. The specific surface area of the inorganic fine particles is preferably 10 to 400 m ² / g, more preferably from 20 to 200 m ² / g, and most preferably from 30 to 150 m ² / g.
The crystal structure of the inorganic fine particles containing titanium dioxide as a main component is preferably a rutile, rutile / anatase mixed crystal, anatase or amorphous structure, particularly preferably a rutile structure. The main component means a component having the largest content (mass%) among the components constituting the particles.

By containing at least one element selected from Co (cobalt), Al (aluminum) and Zr (zirconium) in the inorganic fine particles mainly composed of titanium dioxide, the photocatalytic activity of titanium dioxide can be suppressed, The weather resistance of the high refractive index layer of the present invention can be improved.
A particularly preferable element is Co (cobalt). It is also preferable to use two or more types in combination.

  The contents of Co (cobalt), Al (aluminum), and Zr (zirconium) with respect to Ti (titanium) are each preferably 0.05 to 30% by mass, more preferably 0.1 to 10% with respect to Ti. % By mass, more preferably 0.2-7% by mass, particularly preferably 0.3-5% by mass, most preferably 0.5-3% by mass.

Co (cobalt), Al (aluminum), and Zr (zirconium) can be present in at least one of the inside and the surface of the inorganic fine particles mainly composed of titanium dioxide, but the inorganic fine particles mainly composed of titanium dioxide. It is preferable to exist in the inside of the inside, and it is most preferable to exist in both the inside and the surface.
There are various methods for causing Co (cobalt), Al (aluminum), and Zr (zirconium) to exist (for example, dope) in the inorganic fine particles mainly composed of titanium dioxide. For example, an ion implantation method (Vol.18, No.5, pp.262-268, 1998; Yasushi Aoki), Japanese Patent Laid-Open Nos. 11-263620, 11-512336, and European Published Patent No. 0335773 are disclosed. And a method described in JP-A-5-330825.
In the process of forming inorganic fine particles mainly composed of titanium dioxide, a method of introducing Co (cobalt), Al (aluminum), and Zr (zirconium) (for example, JP 11-512336, European Patent No. 0335773, JP-A-5-330825) is particularly preferred.

Co (cobalt), Al (aluminum), and Zr (zirconium) are also preferably present as oxides.
The inorganic fine particles mainly composed of titanium dioxide can further contain other elements depending on the purpose. Other elements may be included as impurities. Examples of other elements include Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Mg, Si, P, and S.

The inorganic fine particles mainly composed of titanium dioxide used in the present invention may be surface-treated. The surface treatment is performed using an inorganic compound or an organic compound. Examples of inorganic compounds used for the surface treatment include inorganic compounds containing cobalt (CoO ₂ , Co ₂ O ₃ , Co ₃ O _4, etc.), inorganic compounds containing aluminum (Al ₂ O ₃ , Al (OH) _{3, etc.} Etc.), inorganic compounds containing zirconium (ZrO ₂ , Zr (OH) ₄ etc.), inorganic compounds containing silicon (SiO ₂ etc.), inorganic compounds containing iron (Fe ₂ O ₃ etc.), etc. .
Inorganic compounds containing cobalt, inorganic compounds containing aluminum, and inorganic compounds containing zirconium are particularly preferred, and inorganic compounds containing cobalt, Al (OH) ₃ , and Zr (OH) ₄ are most preferred.
Examples of organic compounds used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Silane coupling agents are most preferred. In particular, the surface treatment is preferably performed with an organometallic compound represented by the following general formula A and derivatives thereof.

Formula A: (R ¹ ) _m —Si (OR ² ) _n

In general formula A, R ¹ represents a substituted or unsubstituted alkyl group or aryl group. R ² represents a substituted or unsubstituted alkyl group or acyl group. m represents an integer of 0 to 3, and n represents an integer of 1 to 4, but the sum of m and n is 4.

In the general formula A, examples of the alkyl group represented by R ¹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a hexyl group, a t-butyl group, a sec-butyl group, a hexyl group, a decyl group, and a hexadecyl group. Can be mentioned. The carbon number of the alkyl group represented by R ¹ is preferably 1-30, more preferably 1-16, and particularly preferably 1-6. Examples of the aryl group represented by R ¹ include a phenyl group and a naphthyl group, and a phenyl group is preferable.

There are no particular limitations on the substituent R ¹ has a halogen atom (fluorine, chlorine, bromine), a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group (a methyl group, an ethyl group, i- propyl group, Propyl group, t-butyl group etc.), aryl group (phenyl group, naphthyl group etc.), aromatic heterocyclic group (furyl group, pyrazolyl group, pyridyl group etc.), alkoxy group (methoxy, ethoxy, i-propoxy group, Hexyloxy group etc.), aryloxy group (phenoxy group etc.), alkylthio group (methylthio group, ethylthio group etc.), arylthio group (phenylthio etc.), alkenyl group (vinyl group, 1-propenyl group etc.), alkoxysilyl group ( Trimethoxysilyl group, triethoxysilyl group, etc.), acyloxy group (acetoxy group, (meth) acryloylio) Si group etc.), alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group etc.), aryloxycarbonyl group (phenoxycarbonyl group etc.), carbamoyl group (carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N-methyl-N-octylcarbamoyl group, etc.), acylamino groups (acetylamino group, benzoylamino group, (meth) acryloylamino group, etc.) and the like are preferable. In addition, in this application, description of (meth) acryloyl etc. represents the meaning of acryloyl or methacryloyl.

  Of these, more preferred are a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, an alkoxysilyl group, an acyloxy group, and an acylamino group, and particularly preferred are an epoxy group and a polymerizable acyloxy group ((meth) acryloyloxy). Group) and a polymerizable acylamino group ((meth) acryloylamino group and the like). These substituents may be further substituted with these substituents.

R ² represents an alkyl group having 1 to 10 carbon atoms and an acyl group having 2 to 10 carbon atoms. Specific examples of these groups, and substituents that these groups can have are those described in the description of R ^1. The same. R ² is preferably an unsubstituted alkyl group or an unsubstituted acyl group, and particularly preferably an unsubstituted alkyl group.

m represents an integer of 0 to 3. n represents an integer of 1 to 4. The sum of m and n is 4. When R ¹ or R ² there are a plurality, the plurality of R ¹ or R ² may be different even in the same, respectively. m is preferably 0, 1, 2 and particularly preferably 1.

  Specific examples of the compound represented by Formula A are shown below, but the present invention is not limited thereto.

Among these specific examples, (1), (12), (18), (19) and the like are particularly preferable.
The content of the compound of the general formula A is preferably 1 to 90% by mass, more preferably 2 to 80% by mass, particularly preferably the total solid content of the layer containing inorganic fine particles mainly composed of titanium dioxide of the present invention. Is 5-50 mass%.

  Examples of titanate coupling agents include metal alkoxides such as tetramethoxy titanium, tetraethoxy titanium, and throat tetraisopropoxy titanium, preneact (KR-TTS, KR-46B, KR-55, KR-41B, etc .; Ajinomoto Co., Inc. ))).

  As the organic compound used for the surface treatment, an organic compound having an anionic group is also preferable, and an organic compound having a carboxyl group, a sulfonic acid group, or a phosphoric acid group is particularly preferable. Stearic acid, lauric acid, oleic acid, linoleic acid, linolenic acid and the like can be preferably used.

  The organic compound used for the surface treatment preferably further has a crosslinked or polymerizable functional group. Examples of the cross-linkable or polymerizable functional group include ethylenically unsaturated groups (for example, (meth) acryl group, allyl group, styryl group, vinyloxy group, etc.) capable of addition reaction / polymerization reaction with radical species, cationic polymerizable group (epoxy) Groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups), and the like. Preferred are groups having an ethylenically unsaturated group.

Two or more kinds of organic compounds used for these surface treatments can be used in combination. It is particularly preferable to use an inorganic compound containing aluminum and an inorganic compound containing zirconium in combination.
The inorganic fine particles mainly composed of titanium dioxide of the present invention may have a core / shell structure as described in JP-A-2001-166104 by surface treatment.

  The shape of the inorganic fine particles mainly composed of titanium dioxide of the present invention is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape, or an indefinite shape, and particularly preferably an indefinite shape or a spindle shape.

[Dispersant]
The inorganic fine particles mainly composed of titanium dioxide of the present invention are preferably used after being dispersed using a dispersant. It is particularly preferable to use a dispersant having an anionic group as the dispersant.
As anionic groups, carboxyl groups, sulfate groups (sulfoxy groups and sulfo groups), phosphoric acid groups (phosphonoxy groups and phosphono groups), groups having acidic protons such as sulfonamide groups, or salts thereof are effective. In particular, a carboxyl group, a sulfo group, a phosphoric acid group and a salt thereof are preferable, and a carboxyl group and a phosphoric acid group are particularly preferable. The number of anionic groups contained in the dispersant per molecule may be one or more.
A plurality of anionic groups may be contained for the purpose of further improving the dispersibility of the inorganic fine particles. The average number is preferably 2 or more, more preferably 5 or more, and particularly preferably 10 or more. Moreover, the anionic group contained in a dispersing agent may contain multiple types in 1 molecule.

The dispersant preferably further contains a crosslinkable or polymerizable functional group. Examples of the crosslinkable or polymerizable functional group include ethylenically unsaturated groups (for example, (meth) acryloyl group, allyl group, styryl group, vinyloxy group, etc.) capable of addition reaction / polymerization reaction by radical species, cationic polymerizable group (epoxy) Groups, oxatanyl groups, vinyloxy groups, etc.), polycondensation reactive groups (hydrolyzable silyl groups, etc., N-methylol groups), and the like. Preferred are functional groups having an ethylenically unsaturated group.
A preferred dispersant used for dispersion of inorganic fine particles mainly composed of titanium dioxide of the present invention is a dispersion having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in the side chain. It is an agent.
The weight average molecular weight (Mw) of the dispersant having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in the side chain is not particularly limited, but is preferably 1000 or more. . The more preferred weight average molecular weight (Mw) of the dispersant is 2,000 to 1,000,000, more preferably 5,000 to 200,000, and particularly preferably 10,000 to 100,000.

The dispersant having an anionic group and a crosslinkable or polymerizable functional group and having the crosslinkable or polymerizable functional group in the side chain has the anionic group in the side chain or terminal. Particularly preferred dispersants are those having an anionic group in the side chain.
Examples of the method for introducing an anionic group into the side chain include an anionic group-containing monomer (for example, (meth) acrylic acid, maleic acid, partially esterified maleic acid, itaconic acid, crotonic acid, 2-carboxyethyl (meth) acrylate. , Polymer reaction such as a method of polymerizing 2-sulfoethyl (meth) acrylate, mono-2- (meth) acryloyloxyethyl ester of phosphoric acid, a method of allowing an acid anhydride to act on a polymer having a hydroxyl group, an amino group, etc. Can be synthesized by using
In the dispersant having an anionic group in the side chain, the composition of the anionic group-containing repeating unit is in the range of 10 ^{−4 to} 100 mol%, preferably 1 to 50 mol%, particularly preferably 5 in the total repeating units. ˜20 mol%.

  On the other hand, as a technique for introducing an anionic group at the terminal, a technique for carrying out a polymerization reaction in the presence of an anionic group-containing chain transfer agent (for example, thioglycolic acid), an anionic group-containing polymerization initiator (for example, Wako Pure Chemical Industries, Ltd.) It can be synthesized by a technique of conducting a polymerization reaction using industrial V-501).

In the preferred dispersant for use in the present invention, examples of the repeating unit having an ethylenically unsaturated group in the side chain include poly-1,2-butadiene and poly-1,2-isoprene structures or (meth) acrylic acid. An ester or amide repeating unit having a specific residue (the -COOR or -CONHR R group) bound thereto can be used. Examples of the specific residue (R _{group), - (CH 2) n} -CR 11 = CR 12 R 13, - (CH 2 O) n-CH 2 CR 11 = CR 12 R 13, - (CH ₂ CH ₂ O) n-CH ₂ CR ¹¹ = CR ¹² R ¹³ ,-(CH ₂ ) n-NH-CO-O-CH ₂ CR ¹¹ = CR ¹² R ¹³ ,-(CH ₂ ) nO-CO-CR ¹¹ = CR ¹² R ¹³ and — (CH ₂ CH ₂ O) ₂ —X (R ^{11 to} R ¹³ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group, An aryloxy group, R ¹¹ and R ¹² or R ¹³ may combine with each other to form a ring, n is an integer of 1 to 10, and X is a dicyclopentadienyl residue) Can be mentioned. Specific examples of the ester residue include —CH ₂ CH═CH ₂ (corresponding to an allyl (meth) acrylate polymer described in JP-A No. 64-17047), —CH ₂ CH ₂ O—CH ₂ CH═CH ₂ , -CH ₂ CH ₂ OCOCH = CH ₂ , -CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , -CH ₂ C (CH ₃ ) = CH ₂ , -CH ₂ CH = CH-C ₆ H ₅ , _{-CH 2 CH 2 OCOCH = CH-} C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and -CH ₂ CH ₂ OX (X is a dicyclopentadienyl residue) are included. Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (Y is a 1-cyclohexenyl residue) and —CH ₂ CH ₂ —OCO—CH═CH ₂ , —CH ₂ CH ₂ —OCO—C (CH ₃ ) ═CH ₂ is included.

  In the dispersant having an ethylenically unsaturated group, a free radical (a polymerization initiation radical or a growth radical of a polymerization process of a polymerizable compound) is added to the unsaturated bond group, and the polymer compound is directly or between molecules. Addition polymerization is carried out through the polymerization chain, and a crosslink is formed between the molecules to cure. Alternatively, atoms in the molecule (for example, hydrogen atoms on carbon atoms adjacent to the unsaturated bond group) are extracted by free radicals to form polymer radicals that are bonded together to form a bridge between the molecules. Harden.

  A method for introducing a cross-linkable or polymerizable functional group into the side chain is, for example, as described in JP-A-3-249653, etc., a crosslinkable or polymerizable functional group-containing monomer (for example, allyl (meth) acrylate, glycidyl (meth) acrylate, Copolymerization of trialkoxysilylpropyl methacrylate, etc., copolymerization of butadiene or isoprene, copolymerization of vinyl monomers having a 3-chloropropionic acid ester moiety followed by dehydrochlorination, crosslinking or polymerization by polymer reaction Can be synthesized by introduction of a functional group (for example, polymer reaction of an epoxy group-containing vinyl monomer to a carboxyl group-containing polymer).

  The cross-linkable or polymerizable functional group-containing unit may constitute all repeating units other than the anionic group-containing repeating unit, preferably 5 to 50 mol% of the total cross-linking or repeating unit, particularly Preferably it is 5-30 mol%.

A preferable dispersant of the present invention may be a copolymer with a suitable monomer other than a monomer having a crosslinkable or polymerizable functional group or an anionic group. Although it does not specifically limit regarding a copolymerization component, It selects from various viewpoints, such as dispersion stability, compatibility with another monomer component, and the intensity | strength of a formed film. Preferable examples include methyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, styrene and the like.
The form of the preferable dispersant of the present invention is not particularly limited, but is preferably a block copolymer or a random copolymer, and particularly preferably a random copolymer from the viewpoint of cost and synthetic ease.

  Specific examples of the dispersant preferably used in the present invention are shown below, but the dispersant for the present invention is not limited thereto. Unless otherwise specified, a random copolymer is represented.

  The amount of the dispersant used with respect to the inorganic fine particles mainly composed of titanium dioxide is preferably in the range of 1 to 50% by mass, more preferably in the range of 5 to 30% by mass, and 5 to 20% by mass. Most preferably it is. Two or more dispersants may be used in combination.

[Ultrafine particles and dispersion method of high refractive index inorganic ultrafine particles]
Composition for forming a layer (layer adjacent to a support, hereinafter referred to as a support adjacent high refractive index layer) containing inorganic fine particles mainly composed of titanium dioxide of the present invention (support adjacent high refractive index) In the layer composition, it is preferable that the high refractive index inorganic particles contained in the composition be an ultrafine particle dispersion having an average particle size of 100 nm or less. Thereby, the stability of the liquid of the composition is improved, and the resulting support-adjacent high-refractive-index layer is uniformly distributed in the form of ultrafine particles in the matrix of the support-adjacent high-refractive index layer. It is possible to form a support-adjacent high refractive index layer which is present in a dispersed state and has uniform optical properties and is transparent. The size of the ultrafine particles present in the matrix of the high refractive index layer adjacent to the support is preferably in the range of an average particle size of 3 to 100 nm, more preferably 5 to 100 nm. In particular, 10 to 80 nm is most preferable.

  Furthermore, it is preferable that large particles having an average particle diameter of 500 nm or more are not included, and it is particularly preferable that large particles having an average particle diameter of 300 nm or more are not included. Thereby, the surface shape for a support adjacent high refractive index layer and also the functional film using this to exhibit functions, such as reflection prevention, can be formed.

  In order to disperse the high refractive index inorganic ultrafine particles into the size of ultrafine particles not containing coarse particles in the above range, a wet dispersion method using a medium having an average particle diameter of less than 0.8 mm together with the dispersant It is preferable to disperse with.

Examples of the wet disperser include conventionally known ones such as a sand grinder mill (eg, a bead mill with pins), a dyno mill, a high-speed impeller mill, a pebble mill, a roller mill, an attritor, and a colloid mill.
In particular, in order to disperse the high refractive index inorganic fine particles of the present invention in ultrafine particles, a sand grinder mill, a dyno mill, and a high-speed impeller mill are preferable.

  As the media used together with the disperser, the average particle size is less than 0.8 mm, the average particle size is within this range, the average particle size of the ultrafine particles is 100 nm or less, and the particle size Uniform ultrafine particles can be obtained. The average particle size of the media is preferably 0.5 mm or less, more preferably 0.05 to 0.3 mm.

  Moreover, as a medium used for wet dispersion, beads are preferable. Specifically, zirconia beads, glass beads, ceramic beads, steel beads, etc. are mentioned, and 0.05 to 0.3 mm from the viewpoint of durability and ultrafine particle formation such that the beads are not easily broken during dispersion. Zirconia beads are particularly preferred.

The dispersion temperature in the dispersion step is preferably 20 to 60 ° C, more preferably 25 to 45 ° C. When dispersed in ultrafine particles at a temperature in this range, re-aggregation and precipitation of the dispersed particles do not occur. This is presumably because the dispersant is appropriately adsorbed onto the inorganic particles and does not cause poor dispersion stability due to desorption of the dispersant from the particles at room temperature.
In such a range, the transparency is uniform, the refractive index is uniform, the film strength is high, and the support-adjacent high refractive index layer can be formed.

Moreover, you may implement a preliminary dispersion process before the said wet dispersion | distribution process. Examples of the disperser used for the preliminary dispersion treatment include a ball mill, a three-roll mill, a kneader, and an extruder.
Furthermore, in order to remove coarse aggregates in the dispersion, the dispersion particles in the dispersion satisfy the above-mentioned range of the average particle diameter and the monodispersity of the particle diameter. It is also preferable to arrange the filter medium so as to be microfiltered. The filter medium for fine filtration preferably has a filtration particle size of 25 μm or less. The type of filter medium for microfiltration is not particularly limited as long as it has the above performance, and examples thereof include a filament type, a felt type, and a mesh type. The material of the filter medium for finely filtering the dispersion is not particularly limited as long as it has the above-described performance and does not adversely affect the coating solution, and examples thereof include stainless steel, polyethylene, polypropylene, and nylon.

  The addition amount of these high refractive index inorganic ultrafine particles is preferably 10 to 90%, more preferably 20 to 70%, particularly preferably 30 to 50% of the total mass of the high refractive index layer adjacent to the support. %.

  Such a high refractive index inorganic ultrafine particle has a particle size sufficiently smaller than the wavelength of light and therefore does not scatter, and the matrix in which the high refractive index inorganic ultrafine particle is dispersed is optically uniform as described above. It is preferable because it behaves as a new material.

[High refractive index layer adjacent to support]
Examples of the support-adjacent high refractive index layer of the present invention include the following [High refractive index primer layer] and [High refractive index functional layer]. However, the function of the support adjacent high refractive index layer of the present invention is not limited to the function of preventing interference spots. A support adjacent high refractive index layer may be provided for other purposes.

[High refractive index primer layer]
When setting the high refractive index layer adjacent to the support as the primer layer of the support, the copolymerization of vinyl chloride, vinylidene chloride, butadiene, (meth) acrylic acid ester, vinyl ester, etc. Examples thereof include water-soluble polymers such as coalescence or latex, low molecular weight polyester, and gelatin. Further, the primer layer can contain a metal oxide such as tin oxide, tin oxide / antimony oxide composite oxide, tin oxide / indium oxide composite oxide, or an antistatic agent such as a quaternary ammonium salt.
Moreover, in order to improve adhesiveness with the functional layer provided on a primer layer, easy-adhesiveness can be added and the function as an adhesive undercoat layer can also be provided to a primer layer. In order to add easy adhesiveness, a primer layer may be provided by applying an easily adhesive coating material.

  As the primer layer coating liquid, an organic solvent system and an aqueous system are conceivable, but either can be used in the present invention. From the viewpoint of safety such as deterioration of the environment due to volatilization, hygiene and resource saving, water-based ones are preferable.

  Examples of the water-based easy-adhesive coating material include water-soluble or water-dispersible polyurethane and copolymer polyurethane resin, and the primer layer can be formed using these. Moreover, a primer layer can also be formed by bridge | crosslinking of the acrylic resin and acrylic modified polyester resin which are described in Unexamined-Japanese-Patent No. 1-108037. Furthermore, a primer layer can also be formed using a styrene-butadiene resin or acrylonitrile-butadiene resin and a specific polyester resin described in JP-B-3-22899. Moreover, the styrene-butadiene-type copolymer and acrylic modified polyester resin which are described in Unexamined-Japanese-Patent No. 10-166517 can also be used.

The refractive index of the primer layer in the present invention can be controlled by changing the mixing ratio of the resin and inorganic fine particles mainly composed of titanium dioxide.
Metal oxide fine particles other than inorganic fine particles mainly composed of titanium dioxide can be used in combination. Examples of the metal oxide fine particles used in combination include those having an average particle size of 100 nm or less, preferably 50 nm or less, such as tin oxide, indium oxide, zinc oxide, zirconium oxide particles, and aluminum oxide particles having a refractive index of greater than 1.6. It is done.

  In the case of forming a primer layer having a high refractive index, a polymer having a high refractive index can be used as a binder in combination with inorganic fine particles mainly composed of titanium dioxide. Of course, a combination of a high refractive index binder and metal oxide fine particles having a high refractive index is also possible. The polymer having a high refractive index used as a binder for the primer layer is preferably a polymer having a cyclic group or a polymer containing a halogen atom other than fluorine. A polymer having a cyclic group is preferred to a polymer containing a halogen atom other than fluorine. A polymer containing both a cyclic group and a halogen atom other than fluorine may be used. The cyclic group includes an aromatic group, a heterocyclic group and an aliphatic ring group. Aromatic groups are particularly preferred. As a halogen atom other than fluorine, a chlorine atom is preferable.

  Examples of polymers having a high refractive index include polybis (4-methacryloylthiophenoxy) sulfide, polyvinylphenyl sulfide, poly-4-methacryloyloxyphenyl-4′-methoxyphenyl thioether, polystyrene, styrene copolymer, polycarbonate, and melamine resin. , Phenol resin, epoxy resin and polyurethane obtained by reaction of cyclic (alicyclic or aromatic) isocyanate and polyol, polythiourethane obtained by reaction of xylylene diisocyanate and benzene diol, trithioisocyanate and trimercaptobenzene Polythiourethane obtained by the reaction with styrene, and polyphenylene sulfide obtained by the reaction of sodium sulfide with dichlorobenzene and dichloroquaterphenyl. A sulfide-based polymer having an aromatic group and a thiourethane-based polymer having an aromatic group are particularly preferable. The above polymer latex is preferably used for the primer layer coating solution. The average particle size of the polymer particles in the latex is preferably 0.01 to 1 μm, and more preferably 0.02 to 0.5 μm. In addition to the latex of the polymer, colloidal silica or a surfactant may be added to the primer layer coating solution.

  The primer layer is preferably formed of a single layer from the viewpoint of productivity, but can be formed of two or more layers as necessary.

When the primer layer having the above-described antireflection function cannot be realized by one layer, two or more layers having different refractive indexes are alternately stacked, and the above-described single layer having the antireflection function is laminated. You may form the layer which has an effect equivalent to.
In addition to the multilayer film equivalent to the single-layer film described above, even if a multi-layer antireflection layer having a true structure of λ / 4-λ / 2-λ / 4 is used, the interface of the present invention can be used. The objective of lowering the reflectance of and preventing interference spots can be achieved, but the productivity is slightly reduced.

The high refractive index primer layer can be provided between the pressure-sensitive adhesive layer and the support when the functional film of the present invention is bonded to an image display device or the like using a pressure-sensitive adhesive. This is particularly effective in a system where the transparency of the film is high and the ultraviolet transmittance is high. In the conventional high refractive index layer adjacent to the support using titanium dioxide fine particles, even if it is provided between the support and the adhesive layer for the purpose of preventing interference spots, ultraviolet rays emitted from sunlight etc. This is because the peripheral organic compound is decomposed by the catalytic action of titanium dioxide in the high refractive index layer adjacent to the support, and the functional film is peeled off from the adhesive.
Therefore, a thin support having a thickness of 100 μm or less is often used, and the functional film has a high ultraviolet transmittance, specifically, a function with a transmittance of 50% or more at a wavelength of 380 nm (long wavelength end of ultraviolet rays). In the case of an adhesive film, it is particularly effective to provide the support-adjacent high refractive index layer of the present invention between the support and the pressure-sensitive adhesive layer.

[Functional layer]
In the functional film of the present invention, a functional layer such as a hard coat layer of 2 μm or more can be laminated on the support-adjacent high refractive index layer directly or via another layer. In the conventional functional layer adjacent to the support using titanium dioxide, when it is destroyed by the photocatalytic action of titanium dioxide, the functional layer of 2 μm or more laminated on it is also peeled off at the same time. At the same time as losing the function that has been done, the appearance damage is also great. In the present invention, since the titanium dioxide fine particles having an optimized composition and excellent weather resistance are used for the support-adjacent high refractive index layer, this appearance damage can be prevented. Since the damage on the appearance is larger as the thickness of the functional layer is larger, the effect of the present invention becomes more conspicuous when the functional layer is 5 μm or more, and becomes more remarkable when the functional layer is 15 μm or more.
When the functional layer is a hard coat layer, the pencil thickness of the surface tends to increase as the thickness increases, and the present invention is particularly effective in such a case.

The higher the refractive index of the support layer of the present invention is, the higher the transparency of the functional layer is and the higher the ultraviolet transmittance is. When a high refractive index layer adjacent to a support is formed by conventional titanium dioxide fine particles and an organic compound binder, most of the ultraviolet rays emitted from sunlight and the like are transmitted through the functional layer, and the catalytic action adjacent to the support causes the dioxide dioxide in the layer. This is to decompose the organic binder around the titanium fine particles.
Therefore, when the total transmittance of the layer laminated on the support adjacent high refractive layer has a transmittance of 50% or more at a wavelength of 380 nm (long wave end of ultraviolet rays), specific inorganic fine particles mainly composed of the titanium dioxide fine particles of the present invention A support-adjacent high refractive index layer containing is particularly effective.

[Hard coat layer]
The functional film of the present invention can be used as a hard coat film by providing a hard coat layer as a functional layer. The hard coat film preferably has a surface hardness of H or more by a pencil hardness test described later, and the hard coat layer is a layer for achieving this pencil hardness. In the present invention, the hard coat layer is provided on the high refractive index primer layer as the support adjacent high refractive index layer, or the support adjacent high refractive index layer itself is used as the high refractive index functional layer and the hard coat layer. To be created. As the hard coat film, by providing a hard coat layer, the pencil hardness of the hard coat side surface is preferably 3H or more, more preferably 4H or more, and particularly preferably 5H or more.

  The method for forming the hard coat layer of the present invention may be any method, but from the viewpoint of productivity, a curable composition that is cured by irradiation with active energy rays is applied, and curing that is cured by irradiation with the active energy rays is performed. A layer made of a conductive resin is preferable.

When a high refractive index support film and a high refractive index primer layer are used and a hard coat layer is provided on the high refractive index primer layer, the refractive index of the resin constituting the hard coat layer is preferably 1.45. 1.6, more preferably 1.50 to 1.55.
The curable resin that is cured by irradiation with active energy rays is preferably a curable resin having two or more acrylic groups in the same molecule. Specific examples include ethylene glycol diacrylate, 1,6-hexanediol diacrylate, bisphenol-A diacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipenta. Polyfunctional urethane acrylates and polyepoxy curable resins obtained by reaction of polyol polyacrylates such as erythritol pentaacrylate and dipentaerythritol hexaacrylate, and polyisocyanate curable resins and hydroxyl-containing acrylates such as hydroxyethyl acrylate and hydroxyethyl acrylate Polyfunctionality obtained by reaction of hydroxyl group-containing acrylate (methacrylate) It can be exemplified port carboxymethyl acrylate. A polymer having an ethylenically unsaturated group in the side chain can also be used.

  In the present invention, for curing the hard coat layer, radiation, gamma rays, alpha rays, electron beams, ultraviolet rays and the like are used as active energy rays. Among these methods, a method of adding a polymerization initiator that generates radicals using ultraviolet rays and curing with ultraviolet rays is particularly preferable.

  The polymerization initiators may be used alone or in combination with a plurality of initiators. The addition amount of the polymerization initiator is 0.1 to 15% by mass with respect to the total mass of the ethylenically unsaturated group-containing curable resin and the ring-opening polymerizable group-containing curable resin contained in the curable composition. It is preferably used in a range, and more preferably in a range of 1 to 10% by mass.

The hard coat layer may be formed of a material having a low refractive index.
For example, in order to increase the hardness of the hard coat layer, a method of filling an organic compound binder with silica inorganic fine particle filler is widely known, but the refractive index of silica filler is as low as 1.46, and the hard filler filled with this is hard. The refractive index of the coat layer is also low (approximately 1.48 to 1.51).
An example of a low refractive index (refractive index 1.49) hard coat composition in which ultrafine colloidal silica particles are dispersed in a UV curable organic compound (Takashi Ukachi, Plastic Hard Coat Material, CMC, 71-77 (2000) Such a low refractive index hard coat layer can also be used.

[High refractive index hard coat layer]
In the present invention, a high refractive index hard coat layer may be used as the high refractive index functional layer.
One purpose is to eliminate the difference in refractive index between the high refractive index support represented by PET and the hard coat layer. The high refractive index hard coat layer of the present invention can be formed by forming a hard coat layer with a material having a high refractive index including specific inorganic fine particles mainly composed of titanium dioxide. Specifically, the materials described in [High refractive index primer layer] can be used.

On the other hand, in order to increase the hardness of the hard coat layer, a method of filling an organic compound binder with inorganic fine particle filler such as alumina, titanium oxide, zirconia, etc. is widely known. The refractive index of the hard coat layer filled with these is as high as 6 to 2.7 (approximately 1.55 to 1.7).
A hard coat film in which a hard coat layer formed only of an organic compound is laminated on a cellulose acylate film has a small difference in refractive index, so that usually strong interference spots are not observed, but the above inorganic fine particle filler is included for the purpose of imparting hardness. When the hard coat layer is laminated, the difference in refractive index increases and interference spots appear strongly. In such a case, it is preferable to reduce interference spots using the high refractive index primer layer.

As an example of the composition for forming the above high refractive index hard coat layer, the resin-forming component of the hard coat layer is a polyfunctional acrylate monomer and contains a powdery inorganic filler such as alumina and titanium oxide. A coating composition is disclosed in US Pat. No. 18,15116. Japanese Patent No. 1416240 describes a photopolymerizable composition containing an inorganic charge material made of alumina.
It is also widely known that a conductive material is mixed in the hard coat layer to impart antistatic properties. When ATO (antimony-doped tin oxide), PTO (phosphorus-doped tin oxide) or ITO (tin-doped indium oxide) is used as the metal oxide fine particles, conductivity can be imparted. These conductive metal oxide fine particles also have a high refractive index and cause the same problems as described above. Examples of organic solvent-based transparent conductive paints are described in (Michio Komatsu, characteristics of antireflection film and optimum design / film production technology, Technical Information Association, 37-39 (2001)).

The case where a hard coat layer having a high refractive index is necessary has been described above with some examples, but the present invention is not limited to these examples.
For other purposes, when a high refractive index hard coat layer is required and a difference in refractive index occurs between the support and the support, the problem of interference spots becomes apparent, and specific inorganic fine particles mainly composed of titanium dioxide of the present invention A primer layer containing is effective.

  As another method of forming a hard coat layer having a high refractive index, there is a method of forming with a polymer having a high refractive index. Examples of the polymer having a high refractive index include a polymer having a cyclic group and a polymer containing a halogen atom other than fluorine. Also included are polymers containing both cyclic groups and halogen atoms other than fluorine. Cyclic groups include aromatic, heterocyclic groups and aliphatic ring groups.

The film thickness of the hard coat layer is not particularly limited, but if it exceeds 10 μm, the interference spots become thinner due to the above-mentioned coherent length relationship, and if it is 20 μm or more, the interference spots are completely eliminated when combined with the high refractive index primer layer of the present invention. It becomes easy to lose. Therefore, from this point, the film thickness of the hard coat layer is 10 μm or more, preferably 20 μm or more, more preferably 30 μm or more. On the other hand, when the thickness is increased, the interference spots are reduced, but it is difficult to bend the film, and cracks due to bending are more likely to occur. Therefore, the thickness is preferably 60 μm or less, more preferably 50 μm or less.
The thickness of a preferable hard coat is 10 to 60 μm, more preferably 20 to 50 μm, and particularly preferably 30 to 50 μm. The hard coat consists of one layer, and two or more layers are possible.

The hard coat layer of the present invention is prepared by dipping the active energy ray curable coating solution on a transparent support, spinner method, spray method, roll coater method, gravure method, wire bar method, slot extrusion coater method (single layer). , Multi-layered), and a known thin film forming method such as a slide coater method, followed by drying, irradiation with active energy rays, and curing.
Drying is preferably performed under conditions where the organic solvent concentration in the applied liquid film is 5% by mass or less after drying, more preferably 2% by mass or less, and even more preferably 1% by mass or less. The drying conditions are affected by the thermal strength of the support, the conveyance speed, the length of the drying process, etc., but the lower the content of the organic solvent as possible is preferable from the viewpoint of increasing the polymerization rate.

  The hard coat layer can have a multi-layer structure, and can be produced by appropriately laminating in order of hardness.

[Antireflection film]
In order to prevent reflection from the film surface, the functional film of the present invention can be provided with an antireflection layer to form an antireflection film. For example, a hard coat film provided with the above hard coat layer has a high surface hardness by providing an antireflection layer excellent in scratch resistance comprising a low refractive index layer and a high refractive index layer on the hard coat layer. It can be set as the antireflection hard coat film which has. In this case, the high refractive index layer and the low refractive index layer are formed in this order on the hard coat layer.

The low refractive index layer and the high refractive index layer are mainly composed of a curable resin that is cured by irradiation with active energy rays, or the low refractive index layer and the high refractive index layer are curable resins that are cured by irradiation with active energy rays. A layer composed of metal oxide fine particles is preferable.
The curable resin that is cured by irradiation with active energy rays is preferably a curable resin having two or more acrylic groups in the same molecule. Specific examples include ethylene glycol diacrylate, 1,6-hexanediol diacrylate, bisphenol-A diacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipenta. Polyfunctional urethane acrylates and polyepoxy curable resins obtained by reaction of polyol polyacrylates such as erythritol pentaacrylate and dipentaerythritol hexaacrylate, and polyisocyanate curable resins and hydroxyl-containing acrylates such as hydroxyethyl acrylate and hydroxyethyl acrylate Polyfunctionality obtained by reaction of hydroxyl group-containing acrylate (methacrylate) It can be exemplified port carboxymethyl acrylate. A polymer having an ethylenically unsaturated group in the side chain can also be used.

  The metal oxide fine particles include titanium dioxide (eg, rutile, rutile / anatase mixed crystal, anatase, amorphous structure), tin oxide, indium oxide, zinc oxide, zirconium oxide having an average particle size of 100 nm or less, preferably 50 nm or less. Examples thereof include particles and aluminum oxide particles having a refractive index of greater than 1.6. Titanium dioxide having a large refractive index is preferred because the amount added can be reduced. Furthermore, it is preferable in terms of light resistance to use titanium dioxide fine particles used in the support adjacent layer of the present invention.

[High refractive index layer and formation method thereof]
In order to increase the affinity between the inorganic fine particles and the organic component, the surface of the inorganic fine particles is preferably treated with a surface modifier containing an organic segment, and the surface modifier can form a bond with the inorganic fine particles or be adsorbed on the inorganic fine particles. Those having a high affinity for the functional group and, on the other hand, a curable resin that is cured by irradiation with active energy rays are preferred.
Examples of the surface modifier having a functional group capable of binding or adsorbing to inorganic fine particles include metal alkoxide curable resins such as silane, aluminum, titanium and zirconium, and phosphoric acid groups, phosphonic acid groups, sulfuric acid groups, sulfonic acid groups, carboxylic acids. A surface modifier having an anionic group such as an acid group is preferred. Furthermore, the functional group having a high affinity with the organic component may be simply a combination of the organic component and the hydrophilicity / hydrophobicity, but a functional group that can be chemically bonded to the organic component is preferable, and an ethylenically unsaturated group is particularly preferable. preferable.
In the present invention, the metal oxide fine particle surface modifier is preferably a metal alkoxide or an acrylic acid copolymer having an anionic group and an ethylenically unsaturated group in the same molecule and an anionic group such as a carboxylic acid. Etc.

Representative examples of these surface modifiers include the following unsaturated double bond-containing coupling agents, phosphate group-containing organic curable resins, sulfate group-containing organic curable resins, carboxylic acid group-containing organic curable resins, and the like. It is done.
S-1 H ₂ C═C (X) COOC ₃ H ₆ Si (OCH ₃ ) _{3
S-2 H 2 C = C} (X) COOC 2 H 4 OTi (OC 2 H 5) 3
S-3 H ₂ C═C (X) COOC ₂ H ₄ OCOC ₅ H ₁₀ OPO (OH) ₂
S-4 (H ₂ C═C (X) COOC ₂ H ₄ OCOC ₅ H ₁₀ O) ₂ POOH
S-5 H ₂ C═C (X) COOC ₂ H ₄ OSO ₃ H
S-6 H ₂ C═C (X) COO (C ₅ H ₁₀ COO) ₂ H
S-7 H ₂ C═C (X) COOC ₅ H ₁₀ COOH
(X represents H or CH ₃ )

The surface modification of these inorganic fine particles is preferably performed in a solution. When inorganic fine particles are mechanically finely dispersed, a surface modifier is present together, or after finely dispersing inorganic fine particles, the surface modifier is added and stirred, or further before finely dispersing inorganic fine particles Alternatively, the surface may be modified (if necessary, heated, dried and then heated, or changed in pH), and then finely dispersed.
As the solution for dissolving the surface modifier, an organic solvent having a large polarity is preferable. Specific examples include known solvents such as alcohols, ketones and esters.

  In the present invention, radiation, gamma rays, alpha rays, electron beams, ultraviolet rays, and the like are used as active energy rays for curing the high refractive index layer. Among these methods, a method of adding a polymerization initiator that generates radicals using ultraviolet rays and curing with ultraviolet rays is particularly preferable.

  Examples of polymerization initiators that generate radicals by ultraviolet rays include known radical generators such as acetophenones, benzophenones, Michler's ketone, benzoylbenzoate, benzoins, α-acyloxime esters, tetramethylthiuram monosulfide, and thioxanthone. Can be used. Further, as mentioned above, since sulfonium salts and iodonium salts that are usually used as photoacid generators also act as radical generators upon irradiation with ultraviolet rays, these may be used alone in the present invention. In addition to a polymerization initiator, a sensitizer may be used for the purpose of increasing sensitivity. Examples of the sensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, and thioxanthone derivatives.

  The polymerization initiators may be used alone or in combination with a plurality of initiators. The addition amount of the polymerization initiator is 0.1 to 15% by mass with respect to the total mass of the ethylenically unsaturated group-containing curable resin and the ring-opening polymerizable group-containing curable resin contained in the curable composition. It is preferably used in a range, and more preferably in a range of 1 to 10% by mass.

  The refractive index of the high refractive index layer comprising a curable resin and metal oxide fine particles that are cured by irradiation with these active energy rays is preferably 1.6 or more, more preferably 1.65 or more, and more than the refractive index of the low refractive index layer. It is preferably 0.2 or more.

[Low refractive index layer]
In the present invention, the low refractive index layer is preferably formed of a cured film of a copolymer comprising a repeating unit derived from a fluorine-containing vinyl monomer and a repeating unit having a (meth) acryloyl group in the side chain as essential constituent components. . The copolymer-derived component preferably occupies 70% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more. From the viewpoint of compatibility between low refractive index and film hardness, and compatibility, a form of adding a curing agent such as polyfunctional (meth) acrylate is not preferable.

The refractive index of the low refractive index layer is preferably 1.20 to 1.49, more preferably 1.20 to 1.45, and particularly preferably 1.20 to 1.44.
The thickness of the low refractive index layer is preferably 50 to 400 nm, and more preferably 50 to 200 nm. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less. The specific strength of the low refractive index layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test under a 1 kg load.
In order to improve the antifouling performance of the film, the surface contact angle with water is preferably 90 ° or more. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.

The copolymer used for the low-refractive-index layer of this invention is demonstrated below.
Examples of the fluorine-containing vinyl monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, etc.), (meth) acrylic acid moieties or fully fluorinated alkyl ester derivatives (for example, biscoat 6FM (trade name) , Osaka Organic Chemical Co., Ltd.), M-2020 (trade name, manufactured by Daikin Co., Ltd.), fully or partially fluorinated vinyl ethers, and the like. Preferred are perfluoroolefins, refractive index, solubility, and transparency. From the viewpoint of availability, hexafluoropropylene is particularly preferable. Increasing the composition ratio of these fluorinated vinyl monomers can lower the refractive index but lowers the film strength. In the present invention, the fluorine-containing vinyl monomer is preferably introduced so that the fluorine content of the copolymer is 20 to 60% by mass, more preferably 25 to 55% by mass, and particularly preferably 30 to 50%. This is a case of mass%.

  The said copolymer has a repeating unit which has a (meth) acryloyl group in a side chain as an essential component. The method for introducing the (meth) acryloyl group into the copolymer is not particularly limited. For example, after synthesizing a polymer having a nucleophilic group such as (i) a hydroxyl group or an amino group, (meth) acrylic acid is used. A method in which chloride, (meth) acrylic anhydride, (meth) acrylic acid and methanesulfonic acid mixed acid anhydride, etc. are allowed to act, (ii) the polymer having the nucleophilic group in the presence of a catalyst such as sulfuric acid ( (Iii) a method of allowing methacrylic acid to act, (iii) a method of causing a compound having both an isocyanate group such as methacryloyloxypropyl isocyanate and (meth) acryloyl group to act on the polymer having the nucleophilic group, and (iv) a polymer having an epoxy group. (V) a method in which (meth) acrylic acid is allowed to act after synthesis of (v) an epoxy group such as glycidyl methacrylate and (meth) on a polymer having a carboxyl group Examples thereof include a method of allowing a compound having an acryloyl group to act, and (vi) a method of dehydrochlorination after polymerizing a vinyl monomer having a 3-chloropropionic acid ester moiety. Among these, in the present invention, it is particularly preferable to introduce a (meth) acryloyl group by the method (i) or (ii) to a polymer containing a hydroxyl group.

  If the composition ratio of these (meth) acryloyl group-containing repeating units is increased, the film strength is improved, but the refractive index is also increased. Generally, the (meth) acryloyl group-containing repeating unit preferably accounts for 5 to 90% by mass, more preferably 30 to 70% by mass, although it varies depending on the type of repeating unit derived from the fluorine-containing vinyl monomer. It is particularly preferred to account for ~ 60% by weight.

  In the copolymer, in addition to the repeating unit derived from the fluorine-containing vinyl monomer and the repeating unit having a (meth) acryloyl group in the side chain, adhesion to the lower layer, Tg of the polymer (contributes to film hardness), solvent Other vinyl monomers can be copolymerized as appropriate from various viewpoints such as solubility, transparency, slipperiness, and dust / stain resistance. A plurality of these vinyl monomers may be combined depending on the purpose, and are preferably introduced in the range of 0 to 65 mol% in the copolymer in total, and more preferably in the range of 0 to 40 mol%. Is particularly preferably in the range of 0 to 30 mol%.

  The vinyl monomer unit that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid) 2-ethylhexyl, 2-hydroxyethyl acrylate), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, etc.), styrene derivatives (styrene, p-hydroxymethylstyrene, p -Methoxystyrene, etc.), vinyl ethers (methyl vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, etc.), vinyl esters (vinyl acetate) Vinyl propionate, vinyl cinnamate, etc.), unsaturated carboxylic acids (acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, etc.), acrylamides (N, N-dimethylacrylamide, N-tertbutylacrylamide, N- Cyclohexyl acrylamide, etc.), methacrylamides (N, N-dimethylmethacrylamide), acrylonitrile and the like.

  As a preferable form of the copolymer used in the present invention, the following general formula (1) may be mentioned.

In the general formula (1), L represents a linking group having 1 to 10 carbon atoms, more preferably a linking group having 1 to 6 carbon atoms, and particularly preferably a linking group having 2 to 4 carbon atoms, which is linear. Alternatively, it may have a branched structure, may have a ring structure, and may have a heteroatom selected from O, N, and S.
Preferred examples include *-(CH ₂ ) ₂ -O-**, *-(CH ₂ ) ₂ -NH-**, *-(CH ₂ ) ₄ -O-**, *-(CH ₂ ) ₆ -O-**, *-(CH ₂ ) ₂ -O- (CH ₂ ) ₂ -O-**, -CONH- (CH ₂ ) ₃ -O-**, * -CH ₂ CH (OH) CH ₂ -O- *, * -CH ₂ CH ₂ OCONH (CH ₂ ) ₃ -O-** (* represents the linking site on the polymer main chain side, and ** represents the linking site on the (meth) acryloyl group side. And the like).
m represents 0 or 1;

  In general formula (1), X represents a hydrogen atom or a methyl group. From the viewpoint of curing reactivity, a hydrogen atom is more preferable.

  In the general formula (1), A represents a repeating unit derived from an arbitrary vinyl monomer, and is not particularly limited as long as it is a constituent component of a monomer copolymerizable with hexafluoropropylene. The polymer Tg (contributes to film hardness), solubility in solvents, transparency, slipperiness, dustproof / antifouling properties, etc., can be selected as appropriate, depending on the purpose. You may be comprised by the monomer.

  Preferred examples include methyl vinyl ether, ethyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether, isopropyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, glycidyl vinyl ether, vinyl ethers such as allyl vinyl ether, vinyl acetate, vinyl propionate, butyric acid. (Meth) such as vinyl esters such as vinyl, methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, glycidyl methacrylate, allyl (meth) acrylate, (meth) acryloyloxypropyltrimethoxysilane Acrylates, styrene, styrene derivatives such as p-hydroxymethylstyrene, crotonic acid, maleic acid, itaconic acid Can be mentioned unsaturated carboxylic acids and derivatives thereof, more preferably ether derivatives, vinyl ester derivatives, particularly preferably a vinyl ether derivative.

  x, y, and z represent mol% of each constituent component, and represent values satisfying 30 ≦ x ≦ 60, 5 ≦ y ≦ 70, and 0 ≦ z ≦ 65. Preferably, 35 ≦ x ≦ 55, 30 ≦ y ≦ 60, and 0 ≦ z ≦ 20, and particularly preferably 40 ≦ x ≦ 55, 40 ≦ y ≦ 55, and 0 ≦ z ≦ 10.

  The following general formula (2) is mentioned as a particularly preferred form of the copolymer used in the present invention.

In the general formula (2), X, x, and y have the same meaning as in the general formula (1), and preferred ranges are also the same.
n represents an integer of 2 ≦ n ≦ 10, preferably 2 ≦ n ≦ 6, and particularly preferably 2 ≦ n ≦ 4.
B represents a repeating unit derived from an arbitrary vinyl monomer, and may be composed of a single composition or a plurality of compositions. As an example, what was demonstrated as an example of A in the said General formula (1) is applicable.
z1 and z2 represent mol% of each repeating unit, and represent values satisfying 0 ≦ z1 ≦ 65 and 0 ≦ z2 ≦ 65. It is preferable that 0 ≦ z1 ≦ 30 and 0 ≦ z2 ≦ 10 respectively, and it is particularly preferable that 0 ≦ z1 ≦ 10 and 0 ≦ z2 ≦ 5.

  The copolymer represented by the general formula (1) or (2) is, for example, a copolymer containing a hexafluoropropylene component and a hydroxyalkyl vinyl ether component having a (meth) acryloyl group by any one of the methods described above. It can be synthesized by introduction.

  Although the preferable example of the said copolymer useful by this invention is shown below, this invention is not limited to these.

  The copolymer used in the present invention is synthesized by synthesizing a precursor such as a hydroxyl group-containing polymer by various polymerization methods such as solution polymerization, precipitation polymerization, suspension polymerization, precipitation polymerization, bulk polymerization, and emulsion polymerization. It can be carried out by introducing a (meth) acryloyl group by the polymer reaction. The polymerization reaction can be performed by a known operation such as a batch system, a semi-continuous system, or a continuous system.

  The polymerization initiation method includes a method using a radical initiator, a method of irradiating light or radiation, and the like. These polymerization methods and polymerization initiation methods are, for example, the revised version of Tsuruta Junji “Polymer Synthesis Method” (published by Nikkan Kogyo Shimbun, 1971), Takatsu Otsu, Masato Kinoshita, “Experimental Methods for Polymer Synthesis” It is described in pp. 47-154 published in 1972.

  Among the above polymerization methods, a solution polymerization method using a radical initiator is particularly preferable. Solvents used in the solution polymerization method include, for example, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, benzene, toluene, acetonitrile, A single organic organic solvent such as methylene chloride, chloroform, dichloroethane, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, or a mixture of two or more thereof may be used, or a mixed solvent with water may be used.

  The polymerization temperature needs to be set in relation to the molecular weight of the polymer to be produced, the type of initiator, etc., and can be from 0 ° C. or lower to 100 ° C. or higher, but it is preferable to carry out the polymerization in the range of 50 to 100 ° C.

The reaction pressure can be selected as appropriate, but it is usually 1-100 kg / cm ² , particularly about 1-30 kg / cm ² . The reaction time is about 5 to 30 hours.

  As the reprecipitation solvent for the obtained polymer, isopropanol, hexane, methanol and the like are preferable.

  The composition for forming a low refractive index layer of the present invention is usually in the form of a liquid, and the copolymer is an essential constituent, and various additives and a radical polymerization initiator are dissolved in an appropriate solvent as necessary. Produced. At this time, the concentration of the solid content is appropriately selected according to the use, but is generally about 0.01 to 60% by mass, preferably 0.5 to 50% by mass, particularly preferably 1% to 20% by mass. %.

  From the viewpoint of film hardness of the low refractive index layer, it is not always advantageous to add an additive such as a curing agent, but from the viewpoint of interfacial adhesion to the high refractive index layer, etc., a polyfunctional (meth) acrylate compound Further, a curing agent such as polyfunctional epoxy compound, polyisocyanate compound, aminoplast, polybasic acid or anhydride thereof, or a small amount of inorganic fine particles such as silica can be added. When adding these, it is preferable that it is the range of 0-30 mass% with respect to the total solid of a low refractive index layer membrane | film | coat, It is more preferable that it is the range of 0-20 mass%, 0-10 mass % Range is particularly preferred.

  In addition, for the purpose of imparting properties such as antifouling properties, water resistance, chemical resistance, and slipping properties, known silicone-based or fluorine-based antifouling agents, slipping agents, and the like can be appropriately added. When these additives are added, it is preferably added in the range of 0 to 20% by mass of the total solid content of the low refractive index layer, and more preferably in the range of 0 to 10% by mass. Particularly preferred is 0 to 5% by mass.

  The radical polymerization initiator may be in any form of generating radicals by the action of heat or generating radicals by the action of light.

As the compound that initiates radical polymerization by the action of heat, organic or inorganic peroxides, organic azo, diazo compounds, and the like can be used.
Specifically, benzoyl peroxide, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide as organic peroxides, hydrogen peroxide, peroxides as inorganic peroxides. Ammonium sulfate, potassium persulfate, etc., 2-azo-bis-isobutyronitrile, 2-azo-bis-propionitrile, 2-azo-bis-cyclohexanedinitrile, etc. as diazo compounds, diazoaminobenzene, p-nitrobenzenediazonium Etc.

When a compound that initiates radical polymerization by the action of light is used, the coating is cured by irradiation with active energy rays.
Examples of such radical photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds , Disulfide compounds, fluoroamine compounds and aromatic sulfoniums. Examples of acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone and 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone is included. Examples of benzoins include benzoin benzene sulfonate, benzoin toluene sulfonate, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether. Examples of the benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Sensitizing dyes can also be preferably used in combination with these photoradical polymerization initiators.

  The amount of the compound that initiates radical polymerization by the action of heat or light may be any amount that can initiate the polymerization of the carbon-carbon double bond, but generally the total amount in the low refractive index layer forming composition is not limited. 0.1-15 mass% is preferable with respect to solid content, More preferably, it is 0.5-10 mass%, Most preferably, it is a case of 2-5 mass%.

  The solvent contained in the low refractive index layer coating liquid composition is not particularly limited as long as the composition containing the fluorine-containing copolymer is uniformly dissolved or dispersed without causing precipitation. A solvent can also be used in combination. Preferred examples include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), ethers (tetrahydrofuran, 1,4-dioxane, etc.), alcohols (methanol, ethanol, isopropyl). Alcohol, butanol, ethylene glycol, etc.), aromatic hydrocarbons (toluene, xylene, etc.), water and the like.

  The low refractive index layer may contain a filler (for example, inorganic fine particles and organic fine particles), a silane coupling agent, a slip agent (silicone compound such as dimethyl silicone), a surfactant, etc. in addition to the fluorine-containing compound. it can. In particular, it is preferable to contain inorganic fine particles, a silane coupling agent, and a slip agent.

  As the inorganic fine particles, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride) and the like are preferable. Particularly preferred is silicon dioxide (silica). The mass average diameter of primary particles of the inorganic fine particles is preferably 1 to 150 nm, more preferably 1 to 100 nm, and most preferably 1 to 80 nm. It is preferable that the inorganic fine particles are more finely dispersed in the outermost layer. The shape of the inorganic fine particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape, a short fiber shape, a ring shape, or an indefinite shape.

  As the silane coupling agent, a compound represented by the general formula A and / or a derivative compound thereof can be used. Preferred are silane coupling agents containing a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, an alkoxysilyl group, an acyloxy group, and an acylamino group, and particularly preferred are an epoxy group and a polymerizable acyloxy group ( (Meth) acryloyl), a silane coupling agent containing a polymerizable acylamino group (acrylamino, methacrylamino).

Particularly preferred among the compounds represented by formula A are compounds having a (meth) acryloyl group as a crosslinkable or polymerizable functional group, such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxy. Silane etc. are mentioned.
As the slip agent, dimethyl silicone and a fluorine-containing compound into which a polysiloxane segment is introduced are preferable.

The low-refractive index layer is a cross-linking reaction by applying light irradiation, electron beam irradiation or heating at the same time as or after application of a coating composition in which a fluorine-containing compound and other optional components contained therein are dissolved or dispersed. Or it is preferable to form by a polymerization reaction.
In particular, when the low refractive index layer is formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound, the crosslinking reaction or the polymerization reaction is preferably performed in an atmosphere having an oxygen concentration of 10% by volume or less. . By forming in an atmosphere having an oxygen concentration of 10% by volume or less, an outermost layer having excellent physical strength and chemical resistance can be obtained.
The oxygen concentration is preferably 6% by volume or less, more preferably 4% by volume or less, particularly preferably 2% by volume or less, and most preferably 1% by volume or less.

  As a method of reducing the oxygen concentration to 10% by volume or less, it is preferable to replace the atmosphere (nitrogen concentration of about 79% by volume, oxygen concentration of about 21% by volume) with another gas, particularly preferably replacement with nitrogen (nitrogen purge). It is to be.

[Antireflection film formation method, etc.]
In the present invention, each layer constituting the antireflection film is preferably prepared by a coating method. When formed by coating, each layer is formed by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, micro gravure coating or extrusion coating (US Pat. No. 2,681, 294 specification). Two or more layers may be applied simultaneously. For the method of simultaneous application, US Pat. Nos. 2,761,791, 2,941,898, 3,508,947, 3,526,528 and Yuji Harasaki, coating engineering Page 253, Asakura Shoten (1973). Wire bar coating, gravure coating, and micro gravure coating are preferred.
In addition to the fine particles, polymerization initiator, and photosensitizer described above, each layer of the antireflection film includes a resin, a dispersant, a surfactant, an antistatic agent, a silane coupling agent, a thickener, and an anti-coloring agent. Agents, colorants (pigments, dyes), antifoaming agents, leveling agents, flame retardants, UV absorbers, adhesion-imparting agents, polymerization inhibitors, antioxidants, surface modifiers, and the like can also be added.

[Physical properties of antireflection film]
In the present invention, the antireflection film preferably has a coefficient of dynamic friction on the surface having the antireflection layer of 0.25 or less in order to improve physical strength (such as scratch resistance). The dynamic friction coefficient described here is the surface on the side having the antireflection layer when a load of 0.98 N is applied to a stainless hard sphere having a diameter of 5 mm and the surface on the side having the antireflection layer is moved at a speed of 60 cm / min. And the coefficient of dynamic friction between 5 mm diameter stainless steel hard spheres. Preferably it is 0.17 or less, Most preferably, it is 0.15 or less.
The antireflection film preferably has a contact angle with water of 90 ° or more on the surface having the antireflection layer in order to improve antifouling performance. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.
When the antireflection film does not have an antiglare function, the haze is preferably as low as possible.
When the antireflection film has an antiglare function, the haze is preferably 0.5 to 50%, more preferably 1 to 40%, and most preferably 1 to 30%.

[Configuration of antireflection film]
A configuration example of the antireflection film of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing a layer structure of an antireflection film having excellent antireflection performance.
The embodiment shown in FIG. 1A has a layer structure in the order of a transparent support 1, a primer layer 2, a hard coat layer 3, a high refractive index layer 4, and a low refractive index layer (outermost layer) 5. The primer layer 2 is a layer containing inorganic fine particles mainly composed of titanium dioxide of the present invention. Further, the transparent support 1, the high refractive index layer 4, and the low refractive index layer 5 have a refractive index that satisfies the following relationship.

Refractive index of high refractive index layer> Refractive index of transparent support> Refractive index of low refractive index layer

  In the layer structure as shown in FIG. 1A, as described in JP-A-59-50401, the high refractive index layer has the following formula (I) and the low refractive index layer has the following formula (II). Satisfying each is preferable in that an antireflection film having further excellent antireflection performance can be produced.

Formula (I) (mλ / 4) × 0.7 <n ₁ d ₁ <(mλ / 4) × 1.3

In the formula (I), m is a positive integer (generally 1, 2 or 3), n ₁ is the refractive index of the high refractive index layer, and d ₁ is the layer thickness (nm) of the high refractive index layer. It is. λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm.

Formula (II) (nλ / 4) × 0.7 <n ₂ d ₂ <(nλ / 4) × 1.3

In formula (II), n is a positive odd number (generally 1), n ₂ is the refractive index of the low refractive index layer, and d ₂ is the layer thickness (nm) of the low refractive index layer. λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm.
In addition, satisfy | filling said numerical formula (I) and numerical formula (II) means m (positive integer, generally 1, 2 or 3) which satisfy | fills numerical formula (I) in the range of each said wavelength, and numerical formula (II) ) Satisfying (a positive odd number, generally 1). The same applies to equations (III) to (VIII) below.

  The mode shown in FIG. 1B is a layer structure in the order of a transparent support 1, a primer layer 2, a hard coat layer 3, a medium refractive index layer 6, a high refractive index layer 4, and a low refractive index layer (outermost layer) 5. Have The primer layer 2 is a layer containing inorganic fine particles mainly composed of titanium dioxide of the present invention. Further, the transparent support 1, the medium refractive index layer 6, the high refractive index layer 4 and the low refractive index layer 5 have a refractive index satisfying the following relationship.

  Refractive index of high refractive index layer> refractive index of medium refractive index layer> refractive index of transparent support> refractive index of low refractive index layer

  In the layer structure as shown in FIG. 1B, as described in JP-A-59-50401, the medium refractive index layer is represented by the following mathematical formula (III), and the high refractive index layer is represented by the following mathematical formula (IV). It is preferable that the low refractive index layer satisfies the following mathematical formula (V) in that an antireflection film having more excellent antireflection performance can be produced.

Formula (III) (hλ / 4) × 0.7 <n ₃ d ₃ <(hλ / 4) × 1.3

In formula (III), h is a positive integer (generally 1, 2 or 3), n ₃ is the refractive index of the medium refractive index layer, and d ₃ is the layer thickness (nm) of the medium refractive index layer. It is. λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm.

Formula (IV) (iλ / 4) × 0.7 <n ₄ d ₄ <(iλ / 4) × 1.3

In formula (IV), i is a positive integer (generally 1, 2 or 3), n ₄ is the refractive index of the high refractive index layer, and d ₄ is the layer thickness (nm) of the high refractive index layer. It is. λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm.

Formula (V) (jλ / 4) × 0.7 <n ₅ d ₅ <(jλ / 4) × 1.3

In the formula (V), j is a positive odd number (generally 1), n ₅ is the refractive index of the low refractive index layer, and d ₅ is the layer thickness (nm) of the low refractive index layer. λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm.

In the layer structure as shown in FIG. 1B, the medium refractive index layer satisfies the following formula (VI), the high refractive index layer satisfies the following formula (VII), and the low refractive index layer satisfies the following formula (VIII). Is particularly preferred.
Here, λ is 500 nm, h is 1, i is 2, and j is 1.

Formula (VI) (hλ / 4) × 0.80 <n ₃ d ₃ <(hλ / 4) × 1.00,
Formula (VII) (iλ / 4) × 0.75 <n ₄ d ₄ <(iλ / 4) × 0.95,
Formula (VIII) (jλ / 4) × 0.95 <n ₅ d ₅ <(jλ / 4) × 1.05

  The high refractive index, medium refractive index, and low refractive index described here refer to the relative refractive index between layers. Moreover, in FIG. 1 (a)-(b), the high refractive index layer is used as a light interference layer, and the antireflection film which has the very outstanding antireflection performance can be produced.

  The reflectance (regular reflectance) of the antireflection layer composed of the high refractive index layer and the low refractive index layer (and the middle refractive index layer) is preferably 3.0% or less, and is 1.5% or less. More preferably. When a hard coat having a refractive index of 1.53 is formed on a PET film having a refractive index of 1.65, the reflectivity at the interface between the PET film and the hard coat is 0.15%. When the present invention is used, the reflectance can be reduced to 0.02%, and the reduction range of the reflectance is 0.13%. The importance of this reduction width increases as the reflectance of the antireflection film decreases.

  The functional film of the present invention is laminated together with layers having functions such as an ultraviolet / infrared absorbing layer, a colored layer, a selective wavelength absorbing layer, an electromagnetic wave shielding layer, in addition to the hard coat layer and the antireflection layer. And is provided as a functional film having high hardness.

  Moreover, as an image display apparatus provided with the functional film of this invention, displays, touch panels, a display board of a portable game, etc., such as CRT, LCD, FED, and EL, are preferable. In particular, a flat CRT television that requires the base material to be PET from the viewpoint of preventing crushing and a PDP in which a part of the base material is made of PET are preferable.

[Production of substrate]
(Preparation of titanium dioxide dispersion)
(1) Preparation of Titanium Dioxide Fine Particle Dispersion 1 As titanium dioxide fine particles, titanium dioxide fine particles (MPT-129C, Ishihara Sangyo Co., Ltd.) containing cobalt and surface-treated with aluminum hydroxide and zirconium hydroxide. TiO ₂ : Co ₃ O ₄ : Al ₂ O ₃ : ZrO ₂ = 90.5: 3.0: 4.0: 0.5 weight ratio).
The following dispersant 38.6 g and cyclohexanone 704.3 g were added to 257.1 g of the titanium dioxide fine particles and dispersed by dynomill to prepare a titanium dioxide dispersion having a mass average diameter of 70 nm.

(2) Preparation of titanium dioxide fine particle dispersion 2 The titanium dioxide fine particle dispersion 1 was changed to use titanium dioxide fine particles (TTO-55N, manufactured by Ishihara Sangyo Co., Ltd.).

(Preparation of primer layer coating solution)
(1) Preparation of primer layer coating liquid (p-1) Dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.) and radical photopolymerization initiator (Irgacure 184, Ciba Geigy) were added to the titanium dioxide fine particle dispersion 1. The total amount of monomers (5% based on the total amount of dipentaerythritol hexaacrylate, anionic monomer and cationic monomer) manufactured by the company, and titanium dioxide fine particles so that the refractive index of the primer layer is 1.59 The mixing ratio of Dispersion 1 was adjusted.

(2) Preparation of primer layer coating liquid (p-2) Titanium dioxide fine particle dispersion 1 was changed to titanium dioxide fine particle dispersion 2 with respect to primer layer coating liquid (p-1). The mixing ratio of the titanium dioxide fine particle dispersion 2 was adjusted so that the refractive index of the primer layer was 1.59.

(3) Preparation of primer layer coating liquid (p-3) The mixing ratio of the titanium dioxide fine particle dispersion 1 was changed so that the refractive index was 1.54 with respect to the primer layer coating liquid (p-1).

(4) Preparation of primer layer coating liquid (p-4) The mixing ratio of the titanium dioxide fine particle dispersion 2 was changed so that the refractive index was 1.54 with respect to the primer layer coating liquid (p-2).

(Application of primer layer)
The said primer layer coating liquid was apply | coated to the single side | surface or both surfaces of a support body, and the base material shown in following Table 1 was produced. As the support, corona-treated both sides of PET (biaxially stretched polyethylene terephthalate film, refractive index 1.65) having a thickness of 100 μm, and TAC film (triacetyl cellulose film (TAC-TD80U, Fuji) having a thickness of 80 μm are used. PC (polycarbonate film: Teijin Pure Ace, refractive index 1.59) having a refractive index of 1.48) and a thickness of 80 μm was used. Moreover, the film thickness shown in Table 1 is the film thickness after drying.

[Preparation of hard coat film]
(Preparation of coating solution for hard coat layer)
(1) Preparation of hard coat layer coating solution (h-1) 1296 g of trimethylolpropane triacrylate (TMPTA: Biscote # 295, manufactured by Nippon Kayaku Co., Ltd.) and polyglycidyl methacrylate (mass average molecular weight: 1.5 × 10 ⁴ ) 80909 g of a 53.2 mass% methyl ethyl ketone solution was dissolved in a mixed solution of 943 g of methyl ethyl ketone and 880 g of cyclohexanone, and then stirred with Irgacure 184, 48.1 g, and di (t-butylphenyl) iodonium hexafluorophosphate. (Di (t-butylphenyl) iodonium hexafluorophosphate) 24 g was added and stirred for 10 minutes. The mixture was filtered through a polypropylene filter having a pore size of 0.5 μm to prepare a coating solution for a hard coat layer. The refractive index after curing was 1.52.

(2) Preparation of hard coat layer coating liquid (h-2) Dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) and titanium radical fine particle dispersion 1 and radical photopolymerization initiator (Irgacure 184, Ciba)・ Mixed by Specialty Chemicals, 5% of the total amount of monomers (based on the total amount of dipentaerythritol hexaacrylate, anionic monomer and cationic monomer), and the refractive index after curing is 1.60. Thus, the mixing ratio of the titanium dioxide dispersion 1 was adjusted.

(3) Preparation of hard coat layer coating solution (h-3) The mixing ratio of titanium dioxide dispersion 1 was adjusted so that the refractive index after curing was 1.65 with respect to the hard coat coating solution (h-2). changed.

(4) Preparation of Hard Coat Layer Coating Liquid (h-4) Dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.) and a photo radical polymerization initiator (Irgacure 184, Ciba)・ Mixed by Specialty Chemicals, total amount of monomer (5% based on total amount of dipentaerythritol hexaacrylate, anionic monomer and cationic monomer), and the refractive index after curing becomes 1.65 Thus, the mixing ratio of the titanium dioxide dispersion 2 was adjusted.

(4) Preparation of hard coat layer coating liquid (h-5) The mixing ratio of titanium dioxide dispersion 2 was adjusted so that the refractive index after curing was 1.60 with respect to the hard coat coating liquid (h-4). changed.

(Preparation of hard coat film)
On the primer layer (one side) of the above-prepared base material, a hard coat layer coating solution was applied using a gravure coater. After drying at 100 ° C., an irradiance of 400 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ² , the coating layer was cured by irradiating with an irradiation amount of 300 mJ / cm ² to form a hard coat layer having a thickness shown in Table 2. The substrate and sample number are summarized in Table 2.
In Comparative Example Sample 4 preparation, both sides of 100 μm thick PET (biaxially stretched polyethylene terephthalate film, refractive index 1.65) were subjected to corona treatment before application of the hard coat coating solution (h-1).

(Evaluation of hard coat film)
(1) Evaluation of interference spots The sample was rubbed with sandpaper and black magic was applied to prevent reflection on the back surface. The sample was placed on a desk, and a three-wavelength fluorescent lamp (National Parook fluorescent lamp FL20SS · EX) The sample was illuminated with -D / 18), interference spots were observed, and two-stage evaluation was performed according to the following criteria.
○: almost inconspicuous
X: Recognized clearly.

(2) Evaluation of light resistance Using a xenon arc lamp type light resistance tester (XF type) adjusted to the average outdoor sunlight condition with a borosilicate oxygen glass filter and a quartz filter, irradiation surface illumination 80 klux, black body temperature 63 ° C The light resistance test of each level of exposure time 0 hours and 300 hours was performed in an atmosphere with a relative humidity of 50%.
The hard coat film after exposure was conditioned for 2 hours under conditions of a temperature of 25 ° C. and a relative humidity of 60%.
The surface of the side having the hard coat layer is cut into 11 squares and 11 horizontal cuts with a cutter knife, and a total of 100 square squares are engraved, and a polyester adhesive tape manufactured by Nitto Denko Corporation (NO .31B) was pressed and the adhesion test was repeated three times at the same location. The presence or absence of peeling was visually observed, and the following three-stage evaluation was performed.
○: No more than 10 cm in which peeling was observed in 100 cells,
(Triangle | delta): The thing by which peeling was recognized in 100 squares is a thing of 11-30 squares,
X: The thing in which peeling was recognized in 100 squares exceeded 30 squares.

(3) Appearance of peeled portion after light resistance Since there is a difference in the appearance of the peeled portion after the light resistance test described in (2) above, a four-step evaluation was performed as follows.
○: No peeling part,
Δ: The peeled portion is very difficult to understand,
×: What can be understood when the peeled portion is seen closely,
XX: The peeled portion can be seen immediately.

(4) Evaluation of pencil hardness The hardness of the pencil scratch test is determined by adjusting the humidity of the prepared hard coat film for 2 hours under the conditions of a temperature of 25 ° C. and a relative humidity of 60%, and then the test pencil specified by JIS-S-6006. It is the value of the hardness of the pencil in which scratches are not recognized at a load of 9.8 N according to the pencil hardness evaluation method specified by JIS-K-5400.
(5) Evaluation of haze It measured using haze meter MODEL 1001DP (made by Nippon Denshoku Industries Co., Ltd.).

  The above evaluation results are summarized in Table 3.

From the above results, the following is clear.
From the evaluation results of Example Samples 1 to 6, which are examples of the present invention, the present invention shows no interference spots and has good light resistance.
From the evaluation results of Example Samples 1 to 3 and Comparative Example Samples 1 to 4, when a typical hard coat layer formed of an organic solvent is directly formed on a PET film that is a high refractive index support, the refraction of the hard coat layer is performed. It can be seen that the interference spots are conspicuous from the refractive index difference with the support at a rate of around 1.52. When the layer containing the titanium dioxide fine particles of the present invention is provided between the support and the hard coat layer, interference spots are not visible and the light resistance is good, but those using conventional titanium dioxide fine particles are interference. Spots are not visible, but light resistance is poor.

In addition, from the comparison of Comparative Samples 1 to 3, even if a conventional high refractive index layer (high refractive index primer layer) is provided using conventional titanium dioxide fine particles, a hard coat layer of 2 μm or less is formed on the upper layer. It can be seen that the peeled portion is difficult to recognize, but the one provided with the hard coat layer of 5 μm or more is relatively easy to recognize, and the one provided with the hard coat layer of 15 μm or more can easily recognize the peeled portion.
Therefore, the effect of the present invention is easily recognized when a functional layer such as a hard coat layer having a thickness of 2 μm or more is provided on the high refractive index layer adjacent to the support of the present invention, and further recognized when the thickness is 5 μm or more. It is easy to recognize especially when it is 15 μm or more.

From the evaluation results of Example Sample 6 and Comparative Sample 6, both interference spots and light resistance can be obtained even when a high refractive index hard coat layer using the titanium dioxide fine particles of the present invention is directly provided on a PET film which is a high refractive index support. Although it is good, it can be seen that the high refractive index hard coat layer formed using conventional titanium dioxide fine particles has poor light resistance.
From the evaluation results of Example Sample 5, Comparative Sample 5 and Example Sample 7, when a high refractive index hard coat layer is directly formed on a TAC film which is a low refractive index support using conventional titanium dioxide fine particles, interference spots appear. bad. It can be seen that those provided with the high refractive index primer layer containing the titanium dioxide fine particles of the present invention and the high refractive index hard coat have good interference spots and light resistance.

  From the evaluation results of Example Sample 7 and Comparative Samples 8 and 9, it was found that a PC film as a high refractive index support directly provided with a hard coat layer having a low refractive index consisting only of an organic compound was found to have interference spots due to the difference in refractive index. Can be seen. When conventional titanium dioxide fine particles are used and the refractive index of the hard coat layer is adjusted to the refractive index of the support, interference spots are not visible, but the light resistance is deteriorated. By using the titanium dioxide fine particles of the present invention, the problem of interference spots and light resistance can be solved simultaneously. The present invention is also effective for PC films.

[Production of hard coat film with adhesive layer]
(Preparation of glass plate with hard coat film)
The base material of the hard coat film shown in Example Sample 1 was changed from the base material-1A shown in Table 1 to base material-1B, base material-10, and base material-3B, and acrylic refraction was applied to the B surface. An adhesive layer having a rate of 1.52 is provided and adhered to one side of a 3 mm (thickness) glass plate, and a hard coat film-attached glass plate with an adhesive layer (Example Sample 31, Comparative Example Sample 31, Comparative Example Material) 32) was produced.

(Evaluation of hard coat film with adhesive layer)
The following evaluation was performed on the above-described example sample 31 and comparative example samples 31-32. The results are shown in Table 4.
(1) Evaluation of interference spots Place a black paper on a desk, and place the hard coat pasted glass plate shown in Example Sample 31 and Comparative Example Materials 31 and 32 on the surface so that the hard coat film is on the surface. The sample was illuminated from the side where the hard coat layer was provided with a three-wavelength fluorescent lamp (National Paroch fluorescent lamp FL20SS · EX-D / 18) from above 30 cm, and interference spots were observed.
○: Interference spots are hardly noticeable,
Δ: Interference spots appear thin,
X: Interference spots are clearly recognized.

(2) Evaluation of light resistance Using a xenon arc lamp type light resistance tester (XF type) adjusted to the average outdoor sunlight condition with a borosilicate oxygen glass filter and a quartz filter, irradiation surface illumination 80 klux, black body temperature 63 ° C The light resistance test of each level of exposure time 0 hours and 300 hours was performed in an atmosphere with a relative humidity of 50%.
The hard coat film after exposure was conditioned for 2 hours under conditions of a temperature of 25 ° C. and a relative humidity of 60%.
After that, the surface on the side having the adhesive layer was cut into 11 squares and 11 horizontal cuts in a grid pattern so as to penetrate the hard coat film with a cutter knife. A polyester pressure-sensitive adhesive tape (NO. 31B) manufactured by Co., Ltd. was pressed and the adhesion test was repeated three times at the same place. The presence or absence of peeling was visually observed, and the following three-stage evaluation was performed.
○: No more than 10 cm in which peeling was observed in 100 cells,
(Triangle | delta): The thing by which peeling was recognized in 100 squares is a thing of 11-30 squares,
X: The thing in which peeling was recognized in 100 squares exceeded 30 squares.
(3) Evaluation of haze The haze shown in Table 4 represents the haze of the hard coat film before lamination of the adhesive layer, and the hard coat film before lamination of the adhesive layer is treated with a haze meter MODEL 1001DP (Nippon Denshoku). Measured by Kogyo Co., Ltd.).

From the above results, the following is clear.
What provided the high refractive index primer layer containing the titanium dioxide microparticles | fine-particles of this invention between a support body and an adhesive layer is favorable in both light resistance and an interference spot prevention effect (Example sample 31).
On the other hand, interference spots are observed in the case where the primer layer is not provided (Comparative Example Sample 31), and the conventional titanium dioxide provided with the primer layer can prevent interference spots, but the light resistance is poor (Comparative Example Material). 32) In the conventional technique, it was not possible to achieve both prevention of interference spots and good light resistance.

[Preparation of antireflection film]
(Preparation of coating liquid A for medium refractive index layer)
(1) Preparation of Medium Refractive Index Layer Coating Solution A To 88.9 g of the titanium dioxide dispersion 1 used in [Preparation of Substrate], a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA) 58.4 g, 3.1 g of photopolymerization initiator (Irgacure 907), 1.1 g of photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.), 482.4 g of methyl ethyl ketone and 1869.8 g of cyclohexanone were added and stirred. did. After sufficiently stirring, the solution was filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a coating solution A for medium refractive index layer.

(2) Preparation of Medium Refractive Index Layer Coating Liquid B In the medium refractive index layer coating liquid A, the titanium dioxide dispersion 1 is changed to the titanium dioxide dispersion 2 used in [Preparation of Substrate]. Refractive index layer coating solution B was prepared.

(Preparation of coating liquid A for high refractive index layer)
(1) Preparation of coating solution A for high refractive index layer To 586.8 g of titanium dioxide dispersion 1 used in [Preparation of base material], a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA , Nippon Kayaku Co., Ltd.) 47.9 g, Photopolymerization initiator (Irgacure 907, Nippon Ciba Geigy Co., Ltd.) 4.0 g, Photosensitizer (Kayacure-DETX, Nippon Kayaku Co., Ltd.) 1 .3 g, methyl ethyl ketone 455.8 g, and cyclohexanone 1427.8 g were added and stirred. Filtration through a polypropylene filter having a pore diameter of 0.4 μm prepared a coating solution A for a high refractive index layer.

(2) Preparation of Coating Solution B for High Refractive Index Layer The titanium dioxide dispersion 1 is changed to the titanium dioxide dispersion 2 used in [Preparation of Substrate] with respect to the coating solution A for high refractive index layer. Refractive index layer coating solution B was prepared.

(Preparation of coating solution A for low refractive index layer)
The copolymer (P-1) is dissolved in methyl isobutyl ketone so as to have a concentration of 30% by mass, and a photoradical generator Irgacure 907 (trade name) is added at 5% by mass with respect to the solid content. Layer coating solution A was prepared.

(Preparation of antireflection film)
(1) Creation of Example Sample 11 The base material of the hard coat film shown in Example Sample 3 was changed from Base Material-1A to Base Material-1C to prepare a hard coat film. Further, the medium refractive index layer coating solution A was applied onto the hard coat layer using a gravure coater. After drying at 100 ° C., an illuminance of 550 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 240 W / cm while purging with nitrogen so that the atmosphere has an oxygen concentration of 1.0% by volume or less. ^2. An ultraviolet ray with an irradiation amount of 600 mJ / cm ² was irradiated to cure the coating layer to form a medium refractive index layer (refractive index 1.65, film thickness 67 nm).

On the medium refractive index layer, the coating liquid A for high refractive index layer was applied using a gravure coater. After drying at 100 ° C., an illuminance of 550 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 240 W / cm while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ^{2. The} coating layer was cured by irradiating with an ultraviolet ray having an irradiation amount of 600 mJ / cm ² to form a high refractive index layer (refractive index 1.93, film thickness 107 nm).

On the high refractive index layer, the coating solution A for low refractive index layer was applied using a gravure coater. After drying at 80 ° C. and using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less, the illuminance is 550 mW / A low refractive index layer (refractive index: 1.43, film thickness: 86 nm) was formed by irradiating ultraviolet rays with a cm ² and an irradiation amount of 600 mJ / cm ² . Thus, the antireflection film 101 of the present invention was produced.

(2) Preparation of Example Sample 12 The Example Sample 12 was prepared by changing the medium refractive index coating liquid A to the medium refractive coating liquid B and the high refractive index coating liquid A to the high refractive index coating liquid B. Created.

(3) Preparation of Comparative Example Sample 11 Comparative Example Sample 11 was prepared by changing the base material of Example Sample 11 from Example Sample 2 to Comparative Example Sample 2.

(Evaluation of antireflection film)
(1) Measurement of surface reflectance A sample was prepared by rubbing the back surface with sandpaper and applying black magic so that reflection on the back surface did not occur, and using a spectrophotometer (manufactured by JASCO Corporation), 450- The surface reflectance of regular reflection at 5 ° incident light in the wavelength region of 650 nm was determined.

(2) Interference spot evaluation Place the sample with rubbing the back side with sandpaper and applying black magic so that the reflection on the back side does not occur on the desk, and the three-wavelength fluorescent lamp (National PALUCK fluorescent lamp FL20SS · EX- The sample was illuminated with D / 18), the interference spots were observed, and evaluated in two stages according to the following criteria.
○: almost inconspicuous
X: Recognized clearly.

(3) Evaluation of light resistance Using a xenon arc lamp type light resistance tester (XF type) adjusted to the average outdoor sunlight condition with a borosilicate oxygen glass filter and a quartz filter, irradiation surface illumination 80 klux, black body temperature 63 ° C The light resistance test of each level of exposure time 0 hours and 300 hours was performed in an atmosphere with a relative humidity of 50%.
The antireflection film was conditioned for 2 hours at a temperature of 25 ° C. and a relative humidity of 60%.
Nitto Denko Co., Ltd. made a total of 100 square squares by making 11 vertical and 11 horizontal cuts so that the hard coat film was penetrated with a cutter knife on the surface having the antireflection layer. ) Polyester pressure-sensitive adhesive tape (NO.31B) was pressed and the adhesion test was repeated three times at the same place. The presence or absence of peeling was visually observed, and the following three-stage evaluation was performed.
○: No more than 10 cm in which peeling was observed in 100 cells,
(Triangle | delta): The thing by which peeling was recognized in 100 squares is a thing of 11-30 squares,
X: The thing in which peeling was recognized in 100 squares exceeded 30 squares.

(4) How the peeled portion looks after light resistance Since there is a difference in how the peeled portion looks after the light resistance test described in (3) above, a 43-step evaluation was performed as follows.
○: No peeling part,
Δ: The peeled portion is very difficult to understand,
×: What can be understood when the peeled portion is seen closely,
XX: The peeled portion can be seen immediately.

  Table 5 shows the characteristics of the antireflection film prepared above.

From the above results, the following is clear.
Example Sample 11 of the present invention in which the titanium dioxide fine particles of the present invention were used for the support adjacent high refractive index layer (high refractive index primer layer) and the middle refractive index layer and the high refractive index layer of the antireflection layer was the reflectance. The interference spots are not noticeable and the light resistance is good. Moreover, although the Example sample 12 which used the titanium dioxide fine particle of this invention only for the support body adjacent high refractive index layer can peel in a light resistance test, peeling is restricted to the thin layer of the surface and is not conspicuous. .
On the other hand, in the case where conventional titanium dioxide fine particles are used for the high refractive index layer adjacent to the support, the release layer is thick and the release portion is noticeable.

[Application of antireflection film to PDP front plate]
The antireflection film on the surface of the front plate of the plasma display (PDP-433HD-U Pioneer) is peeled off, and the antireflection hard coat film of Example Sample 11 cut into 10 cm × 10 cm is attached to the center part. A room where a three-wavelength fluorescent lamp (National Parook fluorescent lamp FL40SS / EX-D / 37) was used as room lighting, which was bonded with an acrylic adhesive having a refractive index of 1.52 so that the antireflection layer would be the outermost surface. Observed at. The display provided with the anti-reflection hard coat film had good visibility without interference spots. From this result, it was found that the antireflection hard coat film obtained by the present invention is suitable for a PDP front plate as an image display device.

[Production of transparent plastic film with adhesive layer]
(Preparation of PET film with primer layer)
Both sides of PET (biaxially stretched polyethylene terephthalate film, refractive index 1.65) having a thickness of 50 μm were corona-treated, and the primer layer coating solution (p-1) and (p-2) used in the above [Preparation of substrate] ) Was applied to form a primer layer, and PET films with a primer layer of Examples 21 to 22 and Comparative Example 21 shown in Table 6 were prepared.

(Creation of PET film-laminated glass plate with primer layer)
An acrylic pressure-sensitive adhesive layer having a refractive index of 1.52 was provided on the surface on which the primer layer of the PET film with primer layer prepared above was laminated, and was adhered to one side of a 3 mm (thickness) glass plate. In addition, as a comparative example sample 22, a sample in which the primer layer was not laminated on the example sample 21 was prepared, and a sample having an adhesive layer directly provided on the PET surface was prepared and evaluated according to the following evaluation method. The results are shown in Table 6.

(Evaluation of PET film-laminated glass plate with primer layer)
(1) Evaluation of interference spots Place a black paper on the desk, raise the sample so that the surface on which the film is not pasted becomes the back side, and start from 30 cm above the three-wavelength fluorescent lamp (National Parck fluorescence) The sample was illuminated with a lamp FL20SS · EX-D / 18), interference spots were observed, and two-stage evaluation was performed according to the following criteria.
○: almost inconspicuous
X: Recognized clearly.

(2) Evaluation of light resistance Using a xenon arc lamp type light resistance tester (XF type) adjusted to the average outdoor sunlight condition with a borosilicate oxygen glass filter and a quartz filter, irradiation surface illumination 80 klux, black body temperature 63 ° C The light resistance test of each level of exposure time 0 hours and 300 hours was performed in an atmosphere with a relative humidity of 50%. At this time, the sample was set so that the surface where the film was bonded faced the lamp.
The exposed sample was conditioned for 2 hours under conditions of a temperature of 25 ° C. and a relative humidity of 60%.
Nitto Denko Co., Ltd. Polyester adhesive tape made by cutting 11 square and 11 horizontal cuts in a grid pattern with a cutter knife on the surface to which the sample film was bonded. (NO.31B) was pressure-bonded and the adhesion test was repeated three times at the same place. The presence or absence of peeling was visually observed, and the following three-stage evaluation was performed.
○: No more than 10 cm in which peeling was observed in 100 cells,
(Triangle | delta): The thing by which peeling was recognized in 100 squares is a thing of 11-30 squares,
X: The thing in which peeling was recognized in 100 squares exceeded 30 squares.

From the above results, the following is clear.
What provided the high refractive index primer layer containing the titanium dioxide microparticles | fine-particles of this invention between a support body and an adhesive layer is favorable in both light resistance and an interference spot prevention effect. On the other hand, conventional titanium dioxide fine particles provided with a high refractive index primer layer have a good interference spot prevention effect but a poor light resistance. In addition, a material in which a high refractive index primer layer is not provided and a pressure-sensitive adhesive layer is directly provided on PET has good light resistance but has a poor interference spot prevention effect.

It is a schematic sectional drawing which shows typically the layer structure of the antireflection film excellent in the antireflection performance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent support 2 Primer layer (layer containing the titanium dioxide microparticles | fine-particles of this invention)
3 Hard coat layer 4 High refractive index layer 5 Low refractive index layer (outermost layer)
6 Medium refractive index layer

Claims (9)

  Directly adjacent to at least one surface on a transparent support, having a layer containing inorganic fine particles containing titanium dioxide as a main component and containing at least one element selected from cobalt, aluminum and zirconium, and having a haze of 5.0% A plastic film characterized by:   The plastic film according to claim 1, wherein the inorganic fine particles contain at least cobalt.   The plastic film according to claim 2, wherein the content (mass ratio) of cobalt to titanium is 1% or more. The plastic film according to claim 1, wherein a functional layer having a thickness of 2 μm or more is laminated on the transparent support directly or via another layer on the layer containing the inorganic fine particles. And a refractive index n _S of the transparent support and a refractive index n _H of the functional layer satisfy the following formula (1).
Formula (1): 0.03 ≦ | n _S −n _H | A primer layer including at least a layer containing the inorganic fine particles is provided between the transparent support and the functional layer, and the refractive index n _{P of the} primer layer satisfies the following formula (2): The functional film according to claim 4.
Formula (2)

The functional film according to claim 5, wherein the refractive index n _P and the film thickness d _{P of the} primer layer satisfy the following formula (3).
Formula (3) d _P = (2N−1) × λ / (4n _P )
In Formula (3), λ is a wavelength of visible light and is any value in the range of 450 nm to 650 nm, and N is a natural number.   The plastic film according to any one of claims 1 to 3 or the functional film according to any one of claims 4 to 6, wherein the surface has a pencil hardness of H or more.   The plastic film according to any one of claims 1 to 3 or the functional film according to any one of claims 4 to 7, wherein the antireflection layer is formed directly on the layer containing the inorganic fine particles or via another layer. An antireflection film comprising:   A plastic film according to any one of claims 1 to 3, a functional film according to any one of claims 4 to 7, a hard coat film according to claim 7, or an antireflection film according to claim 8. An image display device characterized by that.

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