JP2007106930A - Film-forming composition, antireflection film, polarizing plate, and image display device - Google Patents

Abstract

[PROBLEMS] To provide a film-forming composition for preparing a coating-type anti-reflection film suitable for mass production, and having sufficient anti-reflection ability, scratch resistance and antifouling property using this film-forming composition. Improved antireflection film, and a polarizing plate and an image display device using the antireflection film are provided.
The main chain contains at least one fluorine-containing copolymer having a polysiloxane segment in the main chain and a fluorine-containing copolymer having a main chain composed of only carbon atoms, and has a polysiloxane segment in the main chain. The composition for film formation whose content rate of a fluorine-containing copolymer is 30 mass% or less with respect to the whole copolymer. An antireflection film comprising a low refractive index layer formed by coating the film-forming composition on a transparent support. A polarizing plate in which this antireflection film is used for one of two protective films of a polarizing film. An image display device in which these antireflection films or polarizing plates are used on the outermost surface of the display.
[Selection figure] None

Description

  The present invention relates to a film-forming composition comprising a fluorine-containing copolymer having a main chain composed only of carbon atoms, and a fluorine-containing copolymer having a polysiloxane segment in the main chain, and the film-forming composition. The present invention relates to an antireflection film used, and a polarizing plate and an image display device using the antireflection film.

  In general, an antireflection film is used for an image display device such as a cathode ray tube display (CRT), a plasma display (PDP), an electroluminescence display (ELD), a liquid crystal display (LCD), etc. In order to prevent reflection of images and images, it is arranged on the outermost surface of the display so as to reduce the reflectance by using the principle of optical interference.

  Such an antireflection film can be generally produced by forming a low refractive index layer having an appropriate thickness on a support or a high refractive index layer formed thereon. As a material for the low refractive index layer, a material having a refractive index as low as possible is desired from the viewpoint of antireflection performance, and at the same time, since it is used for the outermost surface of the display, high scratch resistance is required. In order to realize high scratch resistance in a thin film having a thickness of around 100 nm, it is important to increase the strength of the coating itself and the adhesion to the lower layer.

  In order to lower the refractive index of the material, there are means such as (1) introducing fluorine atoms, (2) lowering the density (introducing voids), etc., both of which decrease the film strength and interface adhesion, The scratch resistance is in the direction of decreasing, and it has been a difficult task to achieve both low refractive index and high scratch resistance. In addition, since the antireflection film is installed on the outermost surface of a display or the like, improvement of antifouling properties such as making it difficult to adhere dirt and facilitating wiping off the attached dirt has been a problem.

  Patent Documents 1 and 2 propose a technique in which a fluorine-containing polymer is applied and then cured to form a low refractive index layer.

  Patent Documents 3 and 4 propose a technique for improving slip resistance by introducing a polysiloxane structure into a fluorine-containing polymer to impart slipperiness.

Patent Document 5 proposes a technique for introducing a polysiloxane structure into a fluorine-containing polymer and increasing the hydroxyl group content.
Japanese Patent No. 3498381 JP 2003-26732 A JP-A-11-189621 Japanese Patent Laid-Open No. 11-228631 JP 2004-307524 A

  The techniques of Patent Document 1 and Patent Document 2 are insufficient in both scratch resistance and antifouling properties.

When the techniques of Patent Document 3 and Patent Document 4 are used, the coefficient of friction on the surface of the film is lowered, which is effective to some extent for improving the scratch resistance, but the essential film strength and interfacial adhesion are insufficient. For the film, sufficient scratch resistance cannot be obtained only by the technique.

  The scratch resistance is improved by the technique of Patent Document 5.

  However, the antifouling property was provided by introducing a polysiloxane structure in the techniques of Patent Documents 3 to 5, but was further improved. Moreover, in order to control the content of the polysiloxane structure to be introduced, it is necessary to cope with it at the manufacturing stage, and it is not always easy to adjust the balance with various performances.

  The present invention firstly provides a film-forming composition for producing a coating-type antireflection film suitable for mass production, and secondly, using such a film-forming composition, Providing an antireflection film having excellent antireflection performance and scratch resistance, and thirdly, providing an antireflection film with improved antifouling properties, and further using such an antireflection film. The object is to provide a polarizing plate and an image display device.

As a result of intensive studies, the present inventors have used a low refractive index layer comprising a fluorine-containing copolymer having a polysiloxane segment and a fluorine-containing copolymer not containing a polysiloxane segment in a specific ratio. Thus, an antireflection film having low reflectivity and excellent scratch resistance and antifouling properties was obtained.
That is, the said subject of this invention was achieved by the following means.

[1] Fluorine containing at least one fluorine-containing copolymer having a polysiloxane segment in the main chain and a fluorine-containing copolymer having a main chain consisting of only carbon atoms, and having a polysiloxane segment in the main chain A film-forming composition, wherein the content of the containing copolymer is 30% by mass or less based on the entire copolymer.

[2] The film forming composition according to [1], wherein the fluorine-containing copolymer having a polysiloxane segment in the main chain includes a structure represented by the following general formula (1).
General formula (1):

In the general formula (1), Rf ¹¹ represents a perfluoroalkyl group having 1 to 5 carbon atoms, Rf ¹² represents a fluorine-containing alkyl group having 1 to 30 carbon atoms, A represents a hydroxyl group-containing vinyl monomer polymerization unit, B Represents an optional component, and R ¹¹ and R ¹² may be the same or different and each represents an alkyl group or an aryl group. a1 to e1 each represent a mole fraction (%) of each constituent component, and relationships of 0 <a1 <50, 0 ≦ b1 ≦ 40, 0 <c1 ≦ 10, 0 ≦ d1 <50, 10 ≦ e1 <100, respectively. Meet.

[3] The film-forming composition as described in [1] above, wherein the fluorine-containing copolymer whose main chain consists only of carbon atoms includes a structure represented by the following general formula (2).
General formula (2):

In the general formula (2), Rf ¹¹ represents a perfluoroalkyl group having 1 to 5 carbon atoms, Rf ¹² represents a fluorine-containing alkyl group having 1 to 30 carbon atoms, A represents a hydroxyl group-containing vinyl monomer polymerization unit, B Represents an optional component. a2 to d2 each represent a mole fraction (%) of each constituent component, and satisfy the relationships of 30 ≦ a2 ≦ 70, 0 ≦ b2 ≦ 40, 0 <c2 ≦ 70, and 0 ≦ d2 ≦ 40, respectively.

[4] The film-forming composition according to any one of [1] to [3], wherein the film-forming composition further comprises a crosslinking agent capable of reacting with a hydroxyl group contained in any of the fluorine-containing copolymers. .

[5] The film forming composition according to any one of [1] to [4], wherein the film forming composition further contains inorganic fine particles.

[6] An antireflection film having a low refractive index layer on a transparent support, wherein the low refractive index layer is formed from the film forming composition according to any one of [1] to [5]. An antireflection film characterized by that.

[7] A polarizing plate, wherein the antireflection film according to [6] is used for one of the two protective films of the polarizing film in the polarizing plate.

[8] An image display device, wherein the antireflection film according to [6] or the polarizing plate according to [7] is used on the outermost surface of the display.

  Since the film forming composition of the present invention has a high fluorine content, the refractive index of the film obtained is low. Moreover, the antireflection film formed from the film forming composition has high antireflection ability and excellent scratch resistance. In addition, since it contains a polysiloxane segment, it is given slipperiness, improved scratch resistance, and excellent antifouling properties. A polarizing plate and a liquid crystal display device using this antireflection film are sufficiently prevented from reflecting external light, have high scratch resistance, and have excellent antifouling properties.

  In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value. The term “polymerization” as used in the present invention is intended to include copolymerization. Furthermore, “on the support” as used in the present invention includes both the case where it refers to the direct surface of the support and the like and the case where it refers to the surface provided with any layer (film) on the support or the like. It is the purpose.

<Film-forming composition>
The film-forming composition of the present invention comprises at least one fluorine-containing copolymer having a polysiloxane segment in the main chain and at least one fluorine-containing copolymer having a main chain composed only of carbon atoms. The content of the fluorine-containing copolymer having a polysiloxane segment in the chain is 30% by mass or less based on the total amount of the fluorine-containing copolymer.
Hereinafter, each fluorine-containing copolymer will be described.

[Fluorine-containing copolymer]
[Fluorine-containing copolymer having polysiloxane segments in the main chain]
The structure of the polymerization unit constituting the fluorine-containing copolymer having a polysiloxane segment in the main chain is not particularly limited as long as it has a polysiloxane segment and a fluorine atom as essential components. Examples thereof include polymerized units based on fluorine-containing olefins, perfluoroalkyl vinyl ethers, vinyl ethers having fluorine-containing alkyl groups, (meth) acrylates, and the like.

Especially, as a fluorine-containing copolymer which has a polysiloxane segment in a principal chain, it is preferable that it is a copolymer represented by following General formula (1).
General formula (1):

In the general formula (1), Rf ¹¹ represents a perfluoroalkyl group having 1 to 5 carbon atoms, Rf ¹² represents a fluorine-containing alkyl group having 1 to 30 carbon atoms, A represents a hydroxyl group-containing vinyl monomer polymerization unit, B Represents an optional component, and R ¹¹ and R ¹² may be the same or different and each represents an alkyl group or an aryl group. a1 to e1 each represent a mole fraction (%) of each constituent component, and relationships of 0 <a1 <50, 0 ≦ b1 ≦ 40, 0 <c1 ≦ 10, 0 ≦ d1 <50, 10 ≦ e1 <100, respectively. Meet.

(Fluorine-containing monomer component represented by general formula M1 or M2)
The copolymer of the general formula (1) includes a fluorine-containing monomer component represented by the following general formula M1 or M2, a monomer component that forms a hydroxyl group-containing vinyl monomer polymerization unit A and an optional component B, and a main chain. The random copolymer which consists of a structural component containing a polysiloxane segment. Each of the constituent components represented by the respective general formulas may be composed of one kind or a plurality of monomers.

In the general formula M1, Rf ¹¹ represents a C 1-5 perfluoroalkyl group, preferably a perfluoromethyl group or a perfluoroethyl group from the viewpoint of polymerization reactivity, and a perfluoromethyl group {in the general formula M1 from the viewpoint of availability. The perfluoroolefin monomer represented is particularly preferably hexafluoropropylene (HFP)}.

  The introduction amount of the monomer represented by the general formula M1, that is, the value of a1 in the general formula (1) is in the range of 0 <a1 <50 mol% and 0 <a1 <25 mol%. In order to increase the introduction rate of the polysiloxane segment of the copolymer, it is more preferable that the range is 0 <a1 <15 mol%.

In the Formula M2, Rf ¹² represents a fluorine-containing alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, particularly preferably containing fluorinated alkyl group having 1 to 10 carbon atoms, 1 to carbon atoms More preferably, it is 10 perfluoroalkyl groups. The fluorinated alkyl group may have a substituent. Specific examples of _{^{Rf 12, -CF 3 [M2- (}} 1)], - CF 2 CF 3 [M2- (2)], - CF 2 CF 2 CF 3 [M2- (3)], - CF 2 CF (OCF ₂ CF ₂ CF ₃ ) CF ₃ [M2- (4)] and the like can be mentioned.

  The introduction amount of the monomer represented by the general formula M2, that is, the value of b1 in the general formula (1) is in the range of 0 ≦ b1 ≦ 40 mol% and 0 ≦ b1 <20 mol%. Preferably, similarly to M1, in order to increase the introduction rate of the polysiloxane segment of the copolymer, it is more preferable that the range is 0 ≦ b1 <10 mol%.

(Hydroxyl group-containing vinyl monomer polymerization unit A)
As the hydroxyl group-containing vinyl monomer, any vinyl ethers, (meth) acrylates, styrenes and the like can be used as long as they are copolymerizable with the above-described fluorine-containing vinyl monomer polymerization unit. For example, when a perfluoroolefin (such as hexafluoropropylene) is used as the fluorine-containing vinyl monomer, it is preferable to use a hydroxyl group-containing vinyl ether having good copolymerization properties, specifically 2-hydroxyethyl vinyl ether, 4-hydroxybutyl. Examples include, but are not limited to, vinyl ether, 6-hydroxyhexyl vinyl ether, 8-hydroxyoctyl vinyl ether, diethylene glycol vinyl ether, triethylene glycol vinyl ether, 4- (hydroxymethyl) cyclohexyl methyl vinyl ether, and the like.

  The introduction amount of these polymerization units A, that is, the value of c1 in the general formula (1) is in the range of 0 <c1 ≦ 10 mol%, preferably in the range of 2 ≦ c1 ≦ 10 mol%, and the hardness of the film In order to increase the ratio and increase the introduction rate of the polysiloxane segment of the copolymer, it is more preferable that the range is 4 ≦ c1 ≦ 10 mol%.

(Optional component B)
Copolymerization components other than those described above, that is, those represented by the component B in the general formula (1), are appropriately selected from various viewpoints such as hardness, adhesion to a substrate, solubility in a solvent, and transparency. Can do. For example, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, t-butyl vinyl ether, n-butyl vinyl ether, cyclohexyl vinyl ether, isopropyl vinyl ether, vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl cyclohexanecarboxylate, etc. As an example.

  In the present invention, when the obtained film-forming composition is used as the optional component B for forming the low refractive index layer, it is represented by the following general formula M3 in order to reduce the refractive index of the formed film. Fluorine-containing vinyl ether may be copolymerized.

In the general formula M3, Rf ¹³ represents a fluorine-containing alkyl group having 1 to 30 carbon atoms, preferably a fluorine-containing alkyl group having 1 to 20 carbon atoms, particularly preferably 1 to 15 carbon atoms, CF ₂ CF ₃ , —CH ₂ (CF ₂ ) ₄ H, —CH ₂ (CF ₂ ) ₈ CF ₃ , —CH ₂ CH ₂ (CF ₂ ) ₄ H, etc.} CF ₃ ) ₂ , CH ₂ CF (CF ₃ ) ₂ , —CH (CH ₃ ) CF ₂ CF ₃ , —CH (CH ₃ ) (CF ₂ ) ₅ CF ₂ H, etc.} It may have an alicyclic structure (preferably a 5- or 6-membered ring such as a perfluorocyclohexyl group, a perfluorocyclopentyl group or an alkyl group substituted with these), and an ether bond (for example, CH ₂ OCH _{2 CF 2 CF 3, CH 2} CH 2 OCH 2 C 4 F 8 H, _{H 2 CH 2 OCH 2 C 6} F 12 H, CH 2 CH 2 OCH 2 CH 2 C 4 F 9, CH 2 CH 2 OCH 2 CH 2 C 6 F 13, CH 2 CH 2 OCF 2 CF 2 OCF 2 CF 2 H) and the like.

  Examples of the monomer represented by the general formula M3 include “Macromolecules”, Vol. 32 (21), p. 7122 (1999), a method in which a fluorine-containing alcohol is allowed to act on a leaving group-substituted alkyl vinyl ether such as vinyloxyalkyl sulfonate and vinyloxyalkyl chloride as described in JP-A-2-721. A method of exchanging vinyl groups by mixing a fluorine-containing alcohol and a vinyl ether such as butyl vinyl ether in the presence of a palladium catalyst as described in International Patent Application No. 92/05135; as described in US Pat. No. 3,420,793. , A method in which a fluorine-containing ketone and dibromoethane are reacted in the presence of a potassium fluoride catalyst, followed by a de-HBr reaction with an alkali catalyst;

  The amount of component B introduced, that is, the value of d1 in the general formula (1) is in the range of 0 ≦ d1 <50 mol%, preferably in the range of 0 ≦ d1 ≦ 30 mol%. In order to increase the introduction rate of the polysiloxane segment of the coalescence, it is more preferable that the range is 0 ≦ d1 ≦ 20 mol%.

(Polysiloxane segment)
R ¹¹ and R ¹² of the polysiloxane segment in the general formula (1) may be the same or different and each represents an alkyl group or an aryl group. The introduction method is not limited as long as it is introduced into the main chain skeleton. That is, it may have an arbitrary structure in addition to the polysiloxane segment, but from the viewpoint of ease of operation, it is preferable to use a polymer polymerization initiator, and radicals such as azo groups and peroxy groups can be generated. This is the case with polysiloxane compounds having groups. In particular, it preferably contains a polysiloxane structure represented by the following general formula (3).
General formula (3):

In General Formula (3), R ¹¹ and R ¹² each independently represent an alkyl group or an aryl group, and R ¹³ and R ¹⁴ each independently represent a hydrogen atom, an alkyl group, a haloalkyl group, or an aryl group. (Preferably a phenyl group), and R ^{15 to} R ¹⁸ each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkoxycarbonyl group or a cyano group. q1 and q2 each independently represents an integer of 1 to 10. q3 and q4 each independently represents an integer of 0 to 10. p represents an integer of 10 to 1000.

  The polymerization initiator represented by the general formula (3) can be synthesized as described in, for example, JP-B-6-104711, JP-A-6-93100, and the like.

  Examples of preferred polymer polymerization initiators are shown below, but the present invention is not limited thereto.

  The amount of polysiloxane segment introduced, that is, the value of e1 in the general formula (1) is in the range of 10 ≦ e1 <100 mol%, preferably in the range of 30 ≦ e1 <100 mol%. In order to sufficiently impart slipping performance and antifouling performance to the film comprising the coalescence, it is more preferable that the range is 50 ≦ e1 <100 mol%.

  The number average molecular weight of the fluorine-containing copolymer having a polysiloxane segment in the main chain in the present invention is preferably in the range of 1,000 to 1,000,000, more preferably 5,000 to 500,000. More preferably, it is the range of 10,000-100,000.

  Although the specific example of the fluorine-containing copolymer which has a polysiloxane segment in the principal chain useful in this invention in Table 1 is shown, this invention is not limited to these. Table 1 shows the molar fraction (%) of the polymerized units.

The abbreviations in Table 1 are as follows.
HFP: hexafluoropropylene,
HEVE: 2-hydroxyethyl vinyl ether,
HBVE: 4-hydroxybutyl vinyl ether,
DEGVE: Diethylene glycol vinyl ether,
HMcHVE: 4- (hydroxymethyl) cyclohexylmethyl vinyl ether,
EVE: ethyl vinyl ether,
cHVE: cyclohexyl vinyl ether,
tBVE: t-butyl vinyl ether,
VAc: vinyl acetate,
_{C 4 F 9 VE: 2- (} 1H, 1H, 2H, 2H- perfluoro hexyloxy) ethyl vinyl ether.

[Fluorine-containing copolymer whose main chain consists only of carbon atoms]
The structure of the polymer unit constituting the fluorine-containing copolymer whose main chain is composed of only carbon atoms is not particularly limited as long as it includes at least one structural unit containing fluorine. Examples include polymerized units based on fluorine-containing olefins, perfluoroalkyl vinyl ethers, vinyl ethers having fluorine-containing alkyl groups, and (meth) acrylates. The fluorine-containing polymer is preferably a copolymer of a fluorine-containing olefin and a vinyl ether because of suitability for production and properties required for a low refractive index layer such as a refractive index and film strength. More preferably, it is a copolymer. Further, as a copolymer component, perfluoroalkyl vinyl ether, vinyl ether having a fluorine-containing alkyl group, (meth) acrylate, or the like may be included for the purpose of reducing the refractive index.
Among these, a copolymer represented by the general formula (2) is preferable.
General formula (2):

In the general formula (2), Rf ¹¹ represents a perfluoroalkyl group having 1 to 5 carbon atoms, and the monomer constituting the polymer unit represented by —CF ₂ CF (Rf ¹¹ ) — The explanation of what was done applies. The monomer constituting the polymer unit represented by —CF ₂ CF (ORf ¹² ) — is the same as that described above as the general formula M2, and the definition and preferred range of Rf ¹² can be similarly applied. A represents a hydroxyl group-containing vinyl monomer polymerization unit, and B represents an optional component. A is the same as the definition of the hydroxyl group-containing vinyl monomer polymerization unit described above, and B is not particularly limited, but vinyl ethers and vinyl esters are preferable from the viewpoint of copolymerization. Specific examples include the monomers exemplified in [Optional Component B] and the monomer represented by Formula M3. A monomer having a polysiloxane structure is also preferable from the viewpoint of imparting antifouling properties. For example, “Silaplane FM-0711”, “Silaplane FM-0721”, “Silaplane FM-0725” manufactured by Chisso Corporation may be used.

  a2 to d2 represent the mole fraction (%) of each constituent component, and 30 ≦ a2 ≦ 70 (more preferably 30 ≦ a2 ≦ 60, more preferably 35 ≦ a2 ≦ 60) and 0 ≦ b2 ≦ 40, respectively. (0 ≦ b2 ≦ 30, more preferably 0 ≦ b2 ≦ 20), 0 <c2 ≦ 70 (more preferably 10 <c2 ≦ 60, still more preferably 20 ≦ c2 ≦ 55, particularly preferably 25 ≦ c2 ≦ 50) , 0 ≦ d2 ≦ 40 (more preferably 0 ≦ d ≦ 30).

  The number average molecular weight of the fluorine-containing copolymer in the present invention is preferably 5,000 to 1,000,000, more preferably 8,000 to 500,000, and particularly preferably 10,000 to 100,000. is there.

  Specific examples of polymers useful in the present invention are shown in Table 2, but the present invention is not limited thereto. Table 2 shows the molar fraction (%) of the polymerized units. Further, FM0721 in Table 2 is a macromonomer having a polysiloxane structure, and refers to “Silaplane FM-0721” (number average molecular weight 5,000) {manufactured by Chisso Corporation}.

  Two types of fluorine-containing copolymers used in the present invention (a fluorine-containing copolymer having a polysiloxane segment in the main chain and a fluorine-containing copolymer having a main chain composed only of carbon atoms) are each one type. It may be used, or a plurality of copolymers may be used in combination. However, the content of the fluorine-containing copolymer having a polysiloxane segment in the main chain should not exceed 30% by mass with respect to the total amount of the fluorine-containing copolymer. Moreover, it is preferable that a polysiloxane segment is added so that it may become 0.1-20 mass% with respect to a fluorine-containing copolymer, It is more preferable that it is 0.5-15 mass%, 1.0- More preferably, it is added so that it may become 10 mass%.

[Synthesis of fluorine-containing copolymer]
The two fluorine-containing copolymers used in the present invention can be synthesized by various polymerization methods such as solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, and emulsion polymerization. Moreover, it is compoundable by well-known operations, such as a batch type, a semi-continuous type, and a continuous type.

  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 are, 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 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 perform polymerization in the range of 40 to 100 ° C. .

  The use of a polymer polymerization initiator (silicone macromer) was cited as a preferred method for introducing the polysiloxane segment. However, if the copolymerization reactivity is poor, the monomer may be added dropwise or divided as appropriate. Good.

  The reaction pressure can be appropriately selected, but is usually 0.01 to 10 MPa, preferably 0.05 to 5 MPa, more preferably about 0.1 to 2 MPa. The reaction time is about 5 to 30 hours.

  The obtained polymer can be used as it is for the application of the present invention, or can be purified by reprecipitation or liquid separation operation.

The film-forming composition of the present invention contains at least one fluorine-containing copolymer having a polysiloxane segment in the main chain described above and a fluorine-containing copolymer having a main chain composed of only carbon atoms. It becomes. If the content of the polysiloxane segment in the film-forming composition becomes too large, the compatibility of the copolymer, the deterioration of the surface condition when the film is formed, and the lack of transparency become problems. Although depending on the content of the polysiloxane segment in the fluorine-containing copolymer having a segment, the fluorine-containing copolymer having a polysiloxane segment is 30% by mass or less based on the copolymer in the film-forming composition. It is necessary to use within the range. If the content of the polysiloxane segment in the fluorine-containing copolymer having a polysiloxane segment is large, it can be used in a smaller proportion.

[Curable resin composition]
[Curing agent (crosslinking agent)]
The film-forming composition of the present invention includes a fluorine-containing copolymer having a polysiloxane segment in the main chain, a fluorine-containing copolymer having a main chain composed only of carbon atoms, and a hydroxyl group in these fluorine-containing copolymers. It is preferable that it is a curable composition containing a compound (curing agent) that can react with the curable resin, that is, a so-called curable resin composition. The curing agent preferably has two or more sites that react with a hydroxyl group, and more preferably has four or more sites.

  The structure of the curing agent is not particularly limited as long as it has the above number of functional groups capable of reacting with hydroxyl groups. For example, polyisocyanates, partial condensates of isocyanate compounds, multimers, polyhydric alcohols, low molecular weight polyester films And the like, block polyisocyanate compounds in which isocyanate groups are blocked with a blocking agent such as phenol, aminoplasts, polybasic acids or anhydrides thereof.

(Aminoplasts)
Among these, in the present invention, aminoplasts that undergo a crosslinking reaction with a hydroxyl group-containing compound under acidic conditions are preferable from the viewpoints of both stability during storage and the activity of the crosslinking reaction, and the strength of the formed film. Aminoplasts contain an amino group capable of reacting with a hydroxyl group present in the fluorine-containing polymer, that is, a hydroxyalkylamino group or an alkoxyalkylamino group, or a carbon atom adjacent to a nitrogen atom and substituted with an alkoxy group. A compound. Specific examples include melamine compounds, urea compounds, benzoguanamine compounds, and the like.

  The melamine compounds are generally known as compounds having a skeleton in which a nitrogen atom is bonded to a triazine ring, and specific examples include melamine, alkylated melamine, methylol melamine, and alkoxylated methyl melamine. . In particular, methylolated melamine and alkoxylated methyl melamine obtained by reacting melamine and formaldehyde under basic conditions and derivatives thereof are preferable, and alkoxylated methyl melamine is particularly preferable in view of storage stability. There are no particular restrictions on methylolated melamine and alkoxylated methylmelamine. For example, use of various resins obtained by the method described in “Plastic Materials Course [8] Urea Melamine Resin” (Nikkan Kogyo Shimbun) Is also possible.

  As the urea compound, in addition to urea, an alkoxylated methylurea which is a polymethylolated urea derivative thereof, and a compound having a glycoluril skeleton or a 2-imidazolidinone skeleton having a cyclic urea structure are also preferable. As for the amino compounds such as the urea derivatives, various resins described in the above-mentioned “Yurea / Melamine resin” can be used.

As a compound suitably used as a crosslinking agent in the present invention, a melamine compound or a glycoluril compound is particularly preferable from the viewpoint of compatibility with a fluorine-containing copolymer, and among these, from the viewpoint of reactivity, the crosslinking agent is in the molecule. The compound preferably contains a nitrogen atom and contains two or more carbon atoms substituted with an alkoxy group adjacent to the nitrogen atom. Particularly preferred compounds are compounds having structures represented by the following structural formulas (H-1) and (H-2), and partial condensates thereof. In the formula, R represents an alkyl group having 1 to 6 carbon atoms or a hydroxyl group.
Structural formulas (H-1) and (H-2):

  As addition amount of aminoplasts with respect to a fluorine-containing copolymer, it is 1-50 mass parts per 100 mass parts of copolymers, Preferably it is 3-40 mass parts, More preferably, it is 5-30 mass parts. is there. If it is 1 part by mass or more, the durability as a thin film that is a feature of the present invention can be sufficiently exhibited, and if it is 50 parts by mass or less, the low refractive index layer in the present invention when used for optical applications. This is preferable because the low refractive index, which is a characteristic of the above, can be maintained. From the viewpoint of keeping the refractive index low even when a curing agent is added, a curing agent that has a small increase in refractive index even when added is preferable, and from this viewpoint, the above compound has a skeleton represented by H-2. Compounds are more preferred.

[Curing catalyst]
Since aminoplasts that are preferably used as a curing agent in the curable resin composition, which is a preferred embodiment of the film-forming composition of the present invention, are cured by an acid catalyst, the curable resin composition includes: It is desirable to add acidic substances. In order to achieve both storage stability and curing activity, it is more preferable to add a compound that generates an acid by heating and / or light irradiation.

(Thermal acid generator)
The compound that generates an acid by heating, that is, a thermal acid generator, can improve the heating conditions to be milder when the coating film of the curable resin composition is heated and cured. It is a possible substance.

  Specific examples of the thermal acid generator include, for example, various aliphatic sulfonic acids and salts thereof; various aliphatic carboxylic acids such as citric acid, acetic acid, and maleic acid; and salts thereof; various aromatics such as benzoic acid and phthalic acid. Examples thereof include carboxylic acids and salts thereof, alkylbenzene sulfonic acids and ammonium salts thereof, seed metal salts; esters of phosphoric acid and organic acids, and the like. The use ratio of the thermal acid generator is preferably 0 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the fluoropolymer in the curable resin composition. If the ratio of the thermal acid generator is less than or equal to the upper limit value, there is no inconvenience such as poor storage stability of the curable resin composition, which is preferable.

(Photosensitive acid generator)
The compound that generates an acid by light irradiation that can be blended in the curable resin composition used in the present invention, that is, a photosensitive acid generator, imparts photosensitivity to the coating film of the curable resin composition, For example, it is a substance that enables the coating film to be photocured by irradiation with radiation such as light.

Typical photosensitive acid generators include, for example, (1) various onium salts such as iodonium salt, sulfonium salt, phosphonium salt, diazonium salt, ammonium salt, pyridinium salt; (2) β-ketoester, β-sulfonylsulfone And sulfone compounds such as α-diazo compounds; (3) sulfonate esters such as alkyl sulfonate, haloalkyl sulfonate, aryl sulfonate, and imino sulfonate; (4) represented by the following general formula (4) (5) diazomethane compounds represented by the following general formula (5); and the like.
General formula (4):

In the general formula (4), Y ⁴¹ represents a divalent group such as an alkylene group, an arylene group, or an alkoxylen group, and R ⁴¹ represents an alkyl group, an aryl group, a halogen-substituted alkyl group, a halogen-substituted aryl group, or the like. A monovalent group is shown.

  General formula (5):

In the general formula (5), R ⁵¹ may be the same or different and represents a monovalent group such as an alkyl group, an aryl group, a halogen-substituted alkyl group, or a halogen-substituted aryl group.

  The photosensitive acid generator can be used alone or in combination of two or more, and can also be used in combination with the thermal acid generator. The use ratio of the photosensitive acid generator is preferably 0 to 20 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the fluorine-containing copolymer in the curable resin composition. If the ratio of the photosensitive acid generator is less than or equal to the upper limit, it is preferable because the resulting cured film has excellent strength and good transparency.

[solvent]
The film-forming composition of the present invention is usually prepared by dissolving a fluorine-containing copolymer in a suitable solvent. Under the present circumstances, although the density | concentration of this copolymer is suitably selected according to a use, generally it is about 0.01-60 mass%, Preferably it is 0.5-50 mass%, Most preferably, it is 1 About 20% by mass.

  The solvent is not particularly limited as long as the composition containing the fluorine-containing copolymer is uniformly dissolved or dispersed without causing precipitation, and two or more kinds of solvents can be used in combination. Preferred examples include ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (eg, ethyl acetate, butyl acetate, etc.), ethers (eg, tetrahydrofuran, 1,4-dioxane, etc.), alcohols (eg, methanol) Ethanol, isopropyl alcohol, butanol, ethylene glycol, etc.), aromatic hydrocarbons (eg, toluene, xylene, etc.), and water.

<Antireflection film>
Next, an antireflection film in which a low refractive index layer is formed using the above solid film forming composition will be described.

[Basic structure of antireflection film]
As an embodiment of the present invention, a basic configuration of a suitable antireflection film will be described with reference to the drawings.

  The cross-sectional view schematically shown in FIG. 1A is an example of the antireflection film of the present invention. The antireflection film 1 a has a layer structure in the order of a transparent support 2, a hard coat layer 3, an antiglare hard coat layer 4, and a low refractive index layer 5.

  Matte particles (not shown) are dispersed in the antiglare hard coat layer 4, and the refractive index of the material other than the matte particles of the antiglare hard coat layer 4 is in the range of 1.48 to 2.00. The refractive index of the low refractive index layer 5 is preferably in the range of 1.20 to 1.47.

  In the present invention, the hard coat layer may be a hard coat layer having an antiglare property as described above, a hard coat layer having no antiglare property, or a single layer, or a plurality of layers, for example, 2 to 4 layers. It may be comprised. Alternatively, there may be no hard coat layer. Accordingly, the hard coat layer 3 and the antiglare hard coat layer 4 shown in FIG. 1 are not essential, but any one of these hard coat layers is preferably applied to impart film strength. The low refractive index layer is coated on the outermost layer.

The cross-sectional view schematically shown in FIG. 1B is an example of the antireflection film of the present invention. The antireflection film 1b includes a transparent support 2, a hard coat layer 3, a medium refractive index 7, and a high refractive index. It has a layer structure in the order of the layer 8 and the low refractive index layer (outermost layer) 5. The transparent support 2, the middle refractive index layer 7, the high refractive index layer 8, and the low refractive index layer 5 have a refractive index that satisfies the following relationship.
The refractive index of the high refractive index layer> the refractive index of the medium refractive index layer> the refractive index of the transparent support> the refractive index of the 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 (1), and the high refractive index layer is represented by the following mathematical formula (2). It is preferable that the low refractive index layer satisfies the following formula (3) in that an antireflection film having more excellent antireflection performance can be produced.

Formula (1): (hλ / 4) × 0.7 <n ₁ d ₁ <(hλ / 4) × 1.3
Formula (2): (iλ / 4) × 0.7 <n ₂ d ₂ <(iλ / 4) × 1.3
Formula (3): (jλ / 4) × 0.7 <n ₃ d ₃ <(jλ / 4) × 1.3

In formulas (1) to (3), h and i are positive integers (generally 1, 2 or 3), and j is a positive odd number (generally 1). n ₁ , n ₂ and n ₃ are the refractive indexes of the medium refractive index layer, the high refractive index layer and the low refractive index layer, respectively, and d ₁ , d ₂ and d ₃ are the medium refractive index layer, the high refractive index layer and the high refractive index layer, respectively. It is the layer thickness (nm) of the refractive index layer and the low refractive index layer. Here, λ is a design wavelength for which the reflectance is desired to be reduced. When the antireflection film is used for a normal display surface, λ is the wavelength (nm) of visible light, and is a value in the range of 380 to 680 nm. In particular, an antireflection film having a low luminous reflectance can be designed by setting λ in the range of 500 to 550 nm, which has a high human visual sensitivity.

  In the layer configuration as shown in FIG. 1B, the medium refractive index layer is represented by the following mathematical formula (1-1), the high refractive index layer is represented by the following mathematical formula (2-1), and the low refractive index layer is represented by the following mathematical formula (3-1). It is particularly preferable that each of these is satisfied. Here, λ is 500 nm, h is 1, i is 2, and j is 1.

Formula (1-1): (hλ / 4) × 0.80 <n ₁ d ₁ <(hλ / 4) × 1.00
Formula (2-1): (iλ / 4) × 0.75 <n ₂ d ₂ <(iλ / 4) × 0.95
Formula (3-1): (jλ / 4) × 0.95 <n ₃ d ₃ <(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 (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.

(Low refractive index layer)
Next, the low refractive index layer in the antireflection film of the present invention will be described below.
The refractive index of the low refractive index layer in the present invention is preferably 1.20 to 1.47, more preferably 1.30 to 1.44.
The thickness of the low refractive index layer in the invention is preferably from 50 nm to 400 nm, more preferably from 60 nm to 150 nm, and most preferably from 60 nm to 130 nm.

Furthermore, the low refractive index layer preferably satisfies the formula (3) as described above from the viewpoint of reducing the reflectance.
Formula (3): (jλ / 4) × 0.7 <n ₃ d ₃ <(jλ / 4) × 1.3
In Equation (3), j is a positive odd number, and n ₃ and d ₃ are the refractive index and film thickness (nm) of the low refractive index layer, respectively, as described above. Here, λ is a design wavelength for which the reflectance is desired to be reduced. In particular, an antireflection film having a low luminous reflectance can be designed by setting λ in the range of 500 to 550 nm, which has a high human visual sensitivity.
In addition, satisfy | filling said Numerical formula (3) means that j (positive odd number, usually 1) which satisfy | fills Numerical formula (3) exists in the said wavelength range.

[Material for low refractive index layer]
(Film-forming composition)
In the present invention, the film forming composition containing the fluorine-containing copolymer described above is used as a low refractive index layer forming composition, and this is coated on a transparent support to form a low refractive index layer. By doing so, an antireflection film can be produced.

  In the present invention, the low refractive index layer is a preferred embodiment in the above-mentioned film forming composition, and further contains inorganic fine particles and an organosilane compound described later, in the curable resin composition containing a curing agent and a curing catalyst. It is also preferable that

(Inorganic fine particles for low refractive index layer)
The amount of the inorganic fine particles to a low refractive index layer is ^{preferably, 1mg / m 2 ~100mg / m} 2 , more preferably ^{5mg / m 2 ~80mg / m 2} , more preferably 10mg / m ² ~60mg / m ² . If the blending amount of the inorganic fine particles is equal to or higher than the lower limit value, the effect of improving the scratch resistance is remarkable, and if it is equal to or lower than the upper limit value, fine irregularities are formed on the surface of the low refractive index layer, black tightening, etc. Therefore, it is preferable to be within the above-mentioned range.

  Since the inorganic fine particles are contained in the low refractive index layer, it is desirable that the inorganic fine particles have a low refractive index. Examples thereof include fine particles of magnesium fluoride and silica. In particular, silica fine particles are preferable in terms of refractive index, dispersion stability, and cost.

  The size of these inorganic fine particles is preferably 1 to 200 nm, more preferably 5 to 90 nm. If the particle size of the inorganic fine particle is equal to or greater than the lower limit, the effect of improving the scratch resistance is increased. If the particle size is equal to or smaller than the upper limit, fine irregularities are formed on the surface of the low refractive index layer, and black tightening, etc. Therefore, it is preferable to be within the above-mentioned range.

  The inorganic fine particles may be either crystalline or amorphous, and may be monodispersed particles or aggregated particles as long as a predetermined particle size is satisfied. The shape is most preferably a spherical diameter, but there is no problem even if the shape is indefinite.

(Organosilane compound)
In the present invention, the low refractive index layer may be formed from a curable composition further comprising an organosilane compound. The definition of the organosilane compound and the structure of the preferred compound are the same as those described in JP-A-2004-331812, [0059] to [0085].

(Other additives)
In the antireflection film of the present invention, when the curable resin composition is used as a composition for forming a low refractive index layer, the composition contains the above-described fluorine-containing copolymer having a polysiloxane segment in the main chain, and the main chain. If necessary, a curing agent, inorganic fine particles, an organosilane compound, various additives, a radical polymerization initiator, and a cationic polymerization initiator are added to a fluorine-containing copolymer consisting of only carbon atoms. It is prepared by dissolving in a solvent. 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 interfacial adhesion between the lower refractive index layer and the lower layer that is in direct contact, a curing agent such as a polyfunctional (meth) acrylate compound, polyfunctional epoxy compound, polyisocyanate compound, aminoplast, polybasic acid, or an anhydride thereof. Can also be added in small amounts. When adding these, it is preferable to set it as the range of 30 mass% or less with respect to the total solid of a low refractive index layer film | membrane, It is more preferable to set it as the range of 20 mass% or less, The range of 10 mass% or less It is particularly preferable that

  In addition, for the purpose of imparting properties such as antifouling property, water resistance, chemical resistance, and slipping property, a known silicone compound or fluorine compound antifouling agent, slipping agent, and the like may be appropriately added. When these additives are added, it is preferably added in the range of 0.01 to 20% by mass of the total solid content of the curable resin composition, more preferably in the range of 0.05 to 10% by mass. Particularly preferably 0.1 to 5% by mass.

  Preferable examples of the silicone compound include those having a substituent at the end of the compound chain and / or the side chain, containing a plurality of dimethylsilyloxy units as repeating units. The compound chain containing dimethylsilyloxy as a repeating unit may contain a structural unit other than dimethylsilyloxy.

  The molecular weight of the silicone compound is not particularly limited, but is preferably 100,000 or less, particularly preferably 50,000 or less, and most preferably 3,000 to 30,000.

  The silicone compound preferably contains a hydroxyl group or a functional group that reacts with the hydroxyl group to form a bond from the viewpoint of preventing the transfer. This bond formation reaction preferably proceeds rapidly under heating conditions and / or in the presence of a catalyst. Examples of such a substituent include an epoxy group and a carboxyl group. Although the following are mentioned as an example of a preferable compound, It is not limited to these.

(Including hydroxyl group)
"X-22-160AS", "KF-6001", "KF-6002", "KF-6003", "X-22-170DX", "X-22-176DX", "X-22-176D", “X-22-176F” {manufactured by Shin-Etsu Chemical Co., Ltd.}; “FM-4411”, “FM-4421”, “FM-4425”, “FM-0411”, “FM-0421”, “ FM-0425 "," FM-DA11 "," FM-DA21 "," FM-DA25 "{above, manufactured by Chisso Corporation};" CMS-626 "," CMS-222 "{above, manufactured by Gelest} .

(Containing functional groups that react with hydroxyl groups)
“X-22-162C”, “KF-105” {manufactured by Shin-Etsu Chemical Co., Ltd.}; “FM-5511”, “FM-5521”, “FM-5525”, “FM-6611”, “ FM-6621 "," FM-6625 "{above, manufactured by Chisso Corporation}.

As the fluorine compound, a compound having a fluoroalkyl group is preferable. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and a straight chain {for example, —CF ₂ CF ₃ , —CH ₂ (CF ₂ ) ₄ H, —CH ₂ (CF ₂ ) ₈ CF ₃ , —CH ₂ CH ₂ (CF ₂ ) ₄ H, etc.}, branched structures {eg, —CH (CF ₃ ) ₂ , —CH ₂ CF (CF ₃ ) ₂ , —CH (CH ₃ ) CF ₂ CF ₃ , —CH (CH ₃ ) (CF ₂ ) ₅ CF ₂ H, etc.}, an alicyclic structure (preferably a 5- or 6-membered ring such as a perfluorocyclohexyl group, A perfluorocyclopentyl group or an alkyl group substituted with these, and may have an ether bond (for example, —CH ₂ OCH ₂ CF ₂ CF ₃ , —CH ₂ CH ₂ OCH ₂ C ₄ F). _{8 H, -CH 2 CH 2 OCH} 2 CH 2 C 8 F 17, -CH 2 CH 2 OCF ₂ CF ₂ OCF ₂ CF ₂ H, etc.). A plurality of the fluoroalkyl groups may be contained in the same molecule.

  It is preferable that the fluorine-based compound further has a substituent that contributes to bond formation or compatibility with the low refractive index layer film. The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group, amino group and the like. The fluorine-based compound may be a polymer or an oligomer with a compound not containing a fluorine atom, and the molecular weight is not particularly limited.

  Although there is no restriction | limiting in particular in fluorine atom content in a fluorine-type compound, It is preferable that it is 20 mass% or more, It is especially preferable that it is 30-70 mass%, It is most preferable that it is 40-70 mass%. . Examples of preferred fluorine-based compounds include "R-2020", "M-2020", "R-3833", "M-3833" (trade names) manufactured by Daikin Industries, Ltd .; Dainippon Ink and Chemicals, Inc. “Megafuck F-171”, “Megafuck F-172”, “Megafuck F-179A”, “Defenser MCF-300” (named above) are available, but are not limited to these. It is not something.

  The curable resin composition for forming the low refractive index layer is further provided with a dust-proofing agent such as a known cationic surfactant or polyoxyalkylene-based compound for the purpose of imparting properties such as dustproofing and antistatic properties, and charging. An inhibitor or the like can be appropriately added. As for these dustproof agent and antistatic agent, the structural unit may be included in the silicone-based compound or the fluorine-based compound as a part of the function.

  When these are added as additives, it is preferably added in the range of 0.01 to 20% by mass of the total solid content of the curable resin composition, more preferably in the range of 0.05 to 10% by mass. It is a case where it is added, and particularly preferably 0.1 to 5% by mass.

  Examples of preferred compounds include “Megafac F-150” (trade name) manufactured by Dainippon Ink & Chemicals, Inc., “SH-3748” (trade name) manufactured by Toray Dow Corning Co., Ltd. However, it is not limited to these.

(Solvent for coating low refractive index layer)
In the present invention, as the solvent used in the coating liquid (curable resin composition) for forming the low refractive index layer, each component can be dissolved or dispersed, and a uniform surface shape in the coating process and the drying process. It is possible to use various solvents selected from the viewpoints of easily becoming liquid, ensuring liquid storage stability, having an appropriate saturated vapor pressure, and the like. From the viewpoint of low load on drying, it is preferable to use a solvent having a boiling point of 100 ° C. or lower at normal pressure and room temperature, and a small amount of solvent having a boiling point of 100 ° C. or higher for adjusting the drying speed. .

  Examples of the solvent having a boiling point of 100 ° C. or lower include hydrocarbons such as hexane (boiling point 68.7 ° C.), heptane (98.4 ° C.), cyclohexane (80.7 ° C.), benzene (80.1 ° C.), Halogenated carbonization such as dichloromethane (39.8 ° C), chloroform (61.2 ° C), carbon tetrachloride (76.8 ° C), 1,2-dichloroethane (83.5 ° C), trichloroethylene (87.2 ° C) Hydrogens, diethyl ether (34.6 ° C), diisopropyl ether (68.5 ° C), dipropyl ether (90.5 ° C), ethers such as tetrahydrofuran (66 ° C), ethyl formate (54.2 ° C), Esters such as methyl acetate (57.8 ° C.), ethyl acetate (77.1 ° C.), isopropyl acetate (89 ° C.), acetone (56.1 ° C.), 2-butanone (methyl ethyl) Ketones such as Luketone, 79.6 ° C, methanol (64.5 ° C), ethanol (78.3 ° C), 2-propanol (82.4 ° C), 1-propanol (97.2 ° C), etc. Alcohols, cyano compounds such as acetonitrile (81.6 ° C.), propionitrile (97.4 ° C.), carbon disulfide (46.2 ° C.), and the like. Of these, ketones and esters are preferable, and ketones are particularly preferable. Among the ketones, 2-butanone is particularly preferable.

  Examples of the solvent having a boiling point of 100 ° C. or more include, for example, octane (125.7 ° C.), toluene (110.6 ° C.), xylene (138 ° C.), tetrachloroethylene (121.2 ° C.), and chlorobenzene (131.7 ° C.). , Dioxane (101.3 ° C.), dibutyl ether (142.4 ° C.), isobutyl acetate (118 ° C.), cyclohexanone (155.7 ° C.), 2-methyl-4-pentanone {same as methyl isobutyl ketone (MIBK), 115.9 ° C.}, 1-butanol (117.7 ° C.), N, N-dimethylformamide (153 ° C.), N, N-dimethylacetamide (166 ° C.), dimethyl sulfoxide (189 ° C.) and the like. Cyclohexanone and 2-methyl-4-pentanone are preferable.

[Method of forming low refractive index layer]
The low refractive index layer of the antireflection film of the present invention can be formed by the following coating method, but is not limited to this method.

  First, a coating solution containing components for forming a low refractive index layer is prepared. Using the obtained coating liquid, dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method, extrusion coating method (see US Pat. No. 2,681,294), etc. Apply on a transparent support by heating and drying. Of these coating methods, the gravure coating method is preferable because a coating solution with a small coating amount can be applied with high film thickness uniformity as in the case of forming each layer of the antireflection film. Among the gravure coating methods, the micro gravure method is more preferable because of high film thickness uniformity.

  The micro gravure coating method used in the present invention is a gravure roll having a diameter of about 10 to 100 mm, preferably about 20 to 50 mm and having a gravure pattern engraved on the entire circumference, below the support and in the transport direction of the support. The gravure roll is rotated in reverse with respect to the gravure roll, the excess coating liquid is scraped off from the surface of the gravure roll by a doctor blade, and a fixed amount of the coating liquid is removed from the support in a position where the upper surface of the support is in a free state. The coating method is characterized in that the coating liquid is transferred onto the lower surface for coating.

  As coating conditions by the micro gravure coating method, the number of lines of the gravure pattern engraved on the gravure roll is preferably 50 to 800 lines / in, more preferably 100 to 300 lines / in, and the depth of the gravure pattern is 1 to 600 μm. Is preferable, 5 to 200 μm is more preferable, the rotation speed of the gravure roll is preferably 3 to 800 rpm, more preferably 5 to 200 rpm, and the conveyance speed of the support is 0.5 to 100 m / min. It is preferably 1 to 50 m / min.

  In order to supply the antireflection film of the present invention with high productivity, an extrusion method (die coating method) is preferably used. Furthermore, since the die coating method is a pre-measuring method, the film thickness control is relatively easy, and further, there is little evaporation of the solvent in the coating part, which is preferable.

[Low refractive index layer curing conditions]
The low refractive index layer in the present invention is in the form of a web after drying of the solvent, and can pass through a coating curing zone by heat and / or ionizing radiation to cure the low refractive index layer. The curing means can be arbitrarily selected depending on the material to be used, but it is also preferable to carry out both of them in succession, whether thermosetting alone or ionizing radiation irradiation alone.

  The conditions for thermosetting are not particularly limited as long as the binder causes a crosslinking reaction, but are preferably 40 to 200 ° C or less, more preferably 60 to 130 ° C, and most preferably 80 to 120 ° C. The heat curing time varies depending on the composition of the curing component, catalyst type and amount, etc., but is 30 seconds to 24 hours, preferably 60 seconds to 1 hour, and most preferably 3 minutes to 20 minutes.

  Although there is no particular limitation on the method of bringing the film surface temperature of the film to a desired temperature, a method of heating a roll to contact the film, a method of spraying heated nitrogen, irradiation with far infrared rays or infrared rays is preferable. A method of flowing hot water or steam through a rotating metal roll described in Japanese Patent No. 2523574 can also be used. On the other hand, at the time of irradiation of ionizing radiation described below, when the film surface temperature of the film rises, a method of cooling the roll and bringing it into contact with the film can be used.

  The ionizing radiation species in the present invention is not particularly limited, and may be selected from ultraviolet rays, electron beams, near ultraviolet rays, visible light, near infrared rays, infrared rays, X-rays, and the like depending on the type of curable composition forming the film. Although it can be appropriately selected, ultraviolet rays and electron beams are preferred, and ultraviolet rays are particularly preferred because they are easy to handle and high energy can be easily obtained.

  As the ultraviolet light source for photopolymerizing the ultraviolet reactive compound, any light source that generates ultraviolet light can be used. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used. Among these, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp can be preferably used.

  Moreover, an electron beam can be used similarly. As an electron beam, 50 to 1000 keV, preferably 100 to 100, emitted from various electron beam accelerators such as a cockroft Walton type, a bandegraph type, a resonance transformation type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. An electron beam having an energy of 300 keV can be given.

Irradiation conditions vary depending on each lamp, but the irradiation light quantity is preferably 10 mJ / cm ² or more, more preferably 50 mJ / cm ^{2 to} 10000 mJ / cm ² , and particularly preferably 50 mJ / cm ^{2 to} 2000 mJ / cm ^2. It is. At that time, the irradiation distribution in the width direction of the web is preferably 50 to 100%, more preferably 80 to 100%, including both ends with respect to the central maximum irradiation.

In the present invention, at least one layer laminated on the support is irradiated with ionizing radiation and heated to a film surface temperature of 60 ° C. or more for 0.5 seconds or more from the start of irradiation with ionizing radiation, with an oxygen concentration of 10 volumes. It is preferable to cure by the step of irradiating ionizing radiation in an atmosphere of less than or equal to%.
It is also preferable to heat in an atmosphere having an oxygen concentration of 3% by volume or less simultaneously and / or continuously with ionizing radiation irradiation.
In particular, the low refractive index layer which is the outermost layer and has a relatively thin film thickness is preferably cured by this method. The curing reaction is accelerated by heat, and a film having excellent physical strength and chemical resistance can be formed.

The irradiation time of ionizing radiation is more preferably 0.7 seconds or more and 60 seconds or less, and further preferably 0.7 seconds or more and 10 seconds or less.
If it is 0.5 second or more, the curing reaction can be completed and sufficient curing can be performed. Also, maintaining low oxygen conditions for a long time is not preferable because the equipment becomes large and a large amount of inert gas is required.

  The oxygen concentration is more preferably formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound in an atmosphere of 6% by volume or less, more preferably 4% by volume or less, particularly preferably 2% by volume of oxygen. % Or less, most preferably 1% by volume or less. In order to reduce the oxygen concentration more than necessary, a large amount of inert gas such as nitrogen is required, which is not preferable from the viewpoint of production cost.

  Moreover, the curing rate (100-residual functional group content) of the layer below the low refractive index layer was set to a value less than 100%, and a low refractive index layer was provided thereon and cured by ionizing radiation and / or heat. If the lower layer has a higher curing rate than before the low refractive index layer is provided, the adhesion between the lower layer and the low refractive index layer is improved, which is preferable.

[Layer structure of antireflection film]
The antireflection film of the present invention has a functional layer having a refractive index different from that of a base material on a transparent base material. The functional layer may be a single layer or a plurality of layers, but at least one of the functional layers is a low refractive index layer formed from the film-forming composition. For example, as an antireflection film, on a transparent base material, if necessary, it has a hard coat layer to be described later, and the refractive index, the film thickness, the number of layers so that the reflectance is reduced by optical interference thereon, The structure laminated | stacked considering the layer order etc. is mentioned.

  In the simplest configuration, the low-reflection antireflection film has a configuration in which only a low refractive index layer is coated on a substrate. In order to further reduce the reflectance, the antireflection layer is preferably constituted by combining a high refractive index layer having a higher refractive index than that of the base material and a low refractive index layer having a lower refractive index than that of the base material. Examples of configurations include two layers of a high refractive index layer / low refractive index layer from the base material side, and three layers having different refractive indices, a medium refractive index layer (having a higher refractive index than the base material or the hard coat layer). , A layer having a refractive index lower than that of a high refractive index layer) / a layer having a high refractive index / a layer having a low refractive index, and the like.

The example of the preferable layer structure of the antireflection film of this invention is shown below. In the following configuration, the base film functions as a support.
・ Base film / low refractive index layer,
・ Base film / Antistatic layer / Low refractive index layer,
・ Base film / Anti-glare layer / Low refractive index layer,
Base film / antiglare layer / antistatic layer / low refractive index layer,
Base film / antistatic layer / antiglare layer / low refractive index layer,
・ Base film / hard coat layer / antiglare layer / low refractive index layer,
・ Base film / hard coat layer / antiglare layer / antistatic layer / low refractive index layer,
・ Base film / hard coat layer / antistatic layer / antiglare layer / low refractive index layer,
・ Base film / hard coat layer / high refractive index layer / low refractive index layer,
・ Base film / hard coat layer / antistatic layer / high refractive index layer / low refractive index layer,
Base film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Base film / antiglare layer / high refractive index layer / low refractive index layer,
Base film / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Base film / antistatic layer / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Antistatic layer / base film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Base film / antistatic layer / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Antistatic layer / base film / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Antistatic layer / base film / antiglare layer / high refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer.

  As long as the reflectance can be reduced by optical interference, it is not limited to these layer configurations. The high refractive index layer may be a light diffusing layer having no antiglare property. The antistatic layer is preferably a layer containing conductive polymer particles or metal oxide fine particles (for example, ATO, ITO), and can be provided by coating or atmospheric pressure plasma treatment.

[Layers other than low refractive index layer]
[Film-forming binder]
In the present invention, as the main film-forming binder component of the film-forming composition for forming a layer other than the low refractive index layer, it is possible to use a compound having an ethylenically unsaturated group to improve film strength, coating solution stability, coating It is preferable in terms of membrane productivity. The main film-forming binder refers to one that accounts for 10% by mass or more of the film-forming components excluding inorganic particles. Preferably, they are 20 mass% or more and 100 mass% or less, More preferably, they are 30 mass% or more and 95% or less.

  A polymer having a saturated hydrocarbon chain or a polyether chain as a main chain is preferable, and a polymer having a saturated hydrocarbon chain as a main chain is more preferable. As the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a (co) polymer of monomers having two or more ethylenically unsaturated groups is preferable.

  In order to make the formed film have a high refractive index, the monomer structure contains an aromatic ring, at least one atom selected from halogen atoms other than fluorine, sulfur atoms, phosphorus atoms, and nitrogen atoms. It is preferable.

Examples of the monomer having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid {for example, ethylene glycol di (meth) acrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetra ( (Meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipenta Erythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester Acrylate, etc.}, vinylbenzene and derivatives thereof (for example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone, etc.), vinylsulfone (for example, divinylsulfone), acrylamide (For example, methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination.
In the present specification, “(meth) acrylate” represents “acrylate or methacrylate”.

  Specific examples of the high refractive index monomer include bis (4-methacryloylthiophenyl) sulfide, vinyl naphthalene, vinyl phenyl sulfide, 4-methacryloxyphenyl-4′-methoxyphenyl thioether, and the like. Two or more of these monomers may be used in combination.

  Polymerization of these monomers having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.

  As radical photopolymerization initiators, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds And 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 benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

  In addition, P. of “Latest UV Curing Technology”. Various examples are also described in 159 {Issuer: Kazuhiro Takasato, Issuer; Technical Information Association, Inc., published in 1991}, which is useful for the present invention.

  Preferable examples of commercially available photocleavable photoradical polymerization initiators include “Irgacure (651, 184, 907)” manufactured by Ciba Specialty Chemicals.

  It is preferable to use a photoinitiator in the range of 0.1-15 mass parts with respect to 100 mass parts of polyfunctional monomers, More preferably, it is the range of 1-10 mass parts.

  In addition to the photopolymerization initiator, a photosensitizer may be used. Specific examples of the photosensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, Michler's ketone and thioxanthone.

  As the thermal radical initiator, 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-azobisisobutyronitrile, 2-azobispropionitrile, 2-azobiscyclohexanedinitrile, etc. as azo compounds, diazoaminobenzene, p-nitrobenzenediazonium, etc. as diazo compounds be able to.

In the present invention, a polymer having a polyether as a main chain can also be used. A ring-opening polymer of a polyfunctional epoxy compound is preferred. Ring-opening polymerization of polyfunctional epoxy compounds
It can be carried out by irradiation with ionizing radiation or heating in the presence of a photoacid generator or a thermal acid generator.

  Instead of or in addition to a monomer having two or more ethylenically unsaturated groups, a monomer having a crosslinkable functional group is used to introduce a crosslinkable functional group into the polymer, and this crosslinkable functional group reacts. A crosslinked structure may be introduced into the binder polymer.

  Examples of the crosslinkable functional group include an isocyanate group, an epoxy group, an aziridine group, an oxazoline group, an aldehyde group, a carbonyl group, a hydrazine group, a carboxyl group, a methylol group, and an active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, in the present invention, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition.

  These binder polymers having a crosslinkable functional group can form a crosslinked structure by heating after coating.

[Hard coat layer]
(Material for hard coat layer)
In the present invention, it is preferable to provide a hard coat layer. The hard coat layer can also serve as an antiglare layer by adding matte particles for imparting antiglare properties to the binder. Moreover, it can serve as a high refractive index layer by adding an inorganic filler for increasing the refractive index, preventing crosslinking shrinkage, and increasing the strength. Further, (organosilane compound) described in [Low refractive index layer] may be added.

(Matte particles)
In the hard coat layer, for the purpose of imparting antiglare properties, mat particles having an average particle size of 0.1 to 5.0 μm, preferably 1.5 to 3.5 μm, such as inorganic compound particles or larger than filler particles. Resin particles can be contained.

  If the difference in refractive index between the matte particles and the binder is too large, the film becomes cloudy, and if it is too small, a sufficient light diffusion effect cannot be obtained, so 0.02 to 0.20 is preferable, and 0.04 to Particularly preferred is 0.10. Similarly to the refractive index, the amount of addition of the matting particles to the binder is too large, the film becomes cloudy, and if it is too small, a sufficient light diffusion effect cannot be obtained. % Is particularly preferred.

As specific examples of the mat particles, inorganic particles such as silica particles and TiO ₂ particles; resin particles such as acrylic particles, crosslinked acrylic particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles are preferable. Can be mentioned. Of these, crosslinked styrene particles, crosslinked acrylic particles, and silica particles are preferred.
As the shape of the mat particle, either a true sphere or an indefinite shape can be used.

Two or more different kinds of mat particles may be used in combination.
When two or more kinds of mat particles are used, the difference in refractive index is preferably 0.02 or more and 0.10 or less in order to effectively exert the refractive index control by mixing the two, and 0.03 or more. Is particularly preferably 0.07 or less. Further, it is possible to impart an antiglare property with mat particles having a larger particle size and to impart another optical characteristic with mat particles having a smaller particle size. For example, when an antireflection film is attached to a high-definition display of 133 ppi or higher, it is required that there is no problem in optical performance called glare. Glare originates from the fact that the pixels are enlarged or reduced due to unevenness existing on the film surface (contributing to anti-glare properties) and lose uniformity of brightness, but with a particle size smaller than that of mat particles that provide anti-glare properties. It can be greatly improved by using mat particles having a different refractive index from the binder.

  Further, the particle size distribution of the mat particles is most preferably monodisperse, and the particle sizes of the particles are preferably closer to each other. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less, more preferably 0.1% of the total number of particles. Or less, more preferably 0.01% or less. Matt particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and a matting agent having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree of classification.

The mat particles are contained in the hard coat layer so that the amount of the mat particles in the formed hard coat layer is preferably 10 to 1000 mg / m ² , more preferably 100 to 700 mg / m ² .

  The particle size distribution of the matte particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution.

(Inorganic filler)
The hard coat layer has at least one selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, in addition to the above mat particles, in order to increase the refractive index of the layer and to reduce curing shrinkage. It is preferable to contain an inorganic filler made of one kind of metal oxide and having an average particle size of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less.

  In order to increase the difference in refractive index from the mat particles, it is also preferable to use a silicon oxide in the hard coat layer using the high refractive index mat particles in order to keep the refractive index of the layer low. The preferred particle size is the same as that of the inorganic filler.

Specific examples of the inorganic filler used in the hard coat layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO, SiO _{2 and the} like. TiO ₂ and ZrO ₂ are particularly preferable in terms of increasing the refractive index.

  The surface of the inorganic filler is also preferably subjected to silane coupling treatment or titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with the binder species on the filler surface is preferably used.

  The amount of these inorganic fillers added is preferably 10 to 90% of the total mass of the hard coat layer, more preferably 20 to 80%, and particularly preferably 30 to 70%.

  Such a filler does not scatter because the particle size is sufficiently smaller than the wavelength of light, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.

  The bulk refractive index of the mixture of binder and inorganic filler in the hard coat layer in the present invention is preferably 1.48 to 2.00, more preferably 1.50 to 1.80. In order to make the refractive index within the above range, the kind and amount ratio of the binder and the inorganic filler may be appropriately selected. How to select can be easily known experimentally in advance.

  The antireflection film of the present invention thus formed has a haze value of 3 to 70%, preferably 4 to 60%, and an average reflectance of 450 nm to 650 nm is preferably 3.0% or less, preferably Is 2.5% or less. When the antireflection film of the present invention has a haze value and an average reflectance within this range, good antiglare properties and antireflection properties can be obtained without causing deterioration of the transmitted image.

[Support]
As the transparent support of the antireflection film of the present invention, a plastic film is preferably used. As a polymer for forming a plastic film, cellulose ester {for example, triacetyl cellulose, diacetyl cellulose, typically “TAC-TD80U”, “TAC-TD80UF”, etc. manufactured by Fuji Photo Film Co., Ltd.}, polyamide, polycarbonate, Polyester (for example, polyethylene terephthalate, polyethylene naphthalate, etc.), polystyrene, polyolefin, norbornene resin {"Arton" (trade name), manufactured by JSR Corporation}, amorphous polyolefin {"ZEONEX" (trade name), Japan ZEON Co., Ltd.}. Of these, triacetyl cellulose, polyethylene terephthalate, and polyethylene naphthalate are preferable, and triacetyl cellulose is particularly preferable.

  In addition, a cellulose acylate film substantially free of halogenated hydrocarbons such as dichloromethane and a method for producing the same are disclosed in JIII Journal of Technical Disclosure No. 2001-1745, published on March 15, 2001, the following. The cellulose acylate described here is also preferably used in the present invention.

[Saponification]
When the antireflection film of the present invention is used in an image display device, it is disposed on the outermost surface of the display by providing an adhesive layer on one side. When the transparent support of the antireflection film is triacetylcellulose, since triacetylcellulose is used as a protective film for protecting the polarizing film of the polarizing plate, it is costly to use the antireflection film of the present invention as it is for the protective film. Preferred above.

  The antireflective film of the present invention is a transparent support in order to sufficiently adhere it when it is disposed on the outermost surface of a display by providing an adhesive layer on one side or used as it is as a protective film for a polarizing plate. It is preferable to carry out a saponification treatment after an outermost layer mainly composed of a fluoropolymer is formed thereon.

  The saponification treatment is performed by a known method, for example, by immersing the film in an alkali solution for an appropriate time. After being immersed in the alkali solution, it is preferable to sufficiently wash with water so that the alkali component does not remain in the film, and to soak in a dilute acid to neutralize the alkali component. By saponification treatment, the surface of the transparent support opposite to the side having the outermost layer is hydrophilized.

  The hydrophilized surface is particularly effective for improving the adhesion with a polarizing film containing polyvinyl alcohol as a main component. In addition, the hydrophilic surface makes it difficult for dust in the air to adhere to it, so when adhering to the polarizing film, it is difficult for dust to enter between the polarizing film and the anti-reflection film, thereby preventing point defects due to dust. It is effective for.

The saponification treatment is preferably carried out so that the contact angle of water on the surface of the transparent support on the side opposite to the side having the outermost layer is 40 ° or less. More preferably, it is 30 ° or less, particularly preferably 20 ° or less.

  Specific means for the alkali saponification treatment can be selected from the following two means (1) and (2). (1) is superior in that it can be processed in the same process as a general-purpose triacetyl cellulose film, but since the surface of the antireflection film is saponified, the surface is alkali-hydrolyzed and the film deteriorates. The point that it becomes dirty when the liquid remains can be a problem. In that case, although it becomes a special process, (2) is excellent.

(1) After the antireflection layer is formed on the transparent support, the back surface of the film is saponified by immersing it in an alkaline solution at least once.
(2) Before or after forming the antireflection layer on the transparent support, an alkaline solution is applied to the surface of the antireflection film opposite to the surface on which the antireflection layer is formed, and is heated, washed and / or neutralized. By doing so, only the back surface of the film is saponified.

[Coating film forming method]
The antireflection film of the present invention can be formed by the following method, but is not limited to this method.

  First, a coating solution containing components for forming each layer is prepared. The coating solution is applied on the transparent support by the dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method, extrusion coating method (see US Pat. No. 2,681,294). Apply, heat and dry.

  Among these coating methods, the gravure coating method is preferable because a coating solution with a small coating amount such as each layer of the antireflection film can be applied with high film thickness uniformity. Among the gravure coating methods, the micro gravure method is more preferable because of high film thickness uniformity.

  Even with the die coating method, it is possible to apply a coating solution with a small coating amount with high film thickness uniformity, and the die coating method is a pre-weighing method, so that the film thickness can be controlled relatively easily. This is preferable because of less evaporation of the solvent.

  In the antireflection film consisting of a plurality of layers, two or more layers may be applied simultaneously. Regarding the method of simultaneous application, U.S. Pat. Nos. 2,761,791, 2,941,898, 3,508,947, 3,526,528 and Yuji Harasaki Author, “Coating Engineering”, page 253, {Asakura Shoten (1973)}.

<Use of antireflection film>
〔Polarizer〕
The polarizing plate is mainly composed of two protective films that sandwich the polarizing film from both sides. The antireflection film of the present invention is preferably used for at least one of the two protective films sandwiching the polarizing film from both sides. Since the antireflection film of the present invention also serves as a protective film, the production cost of the polarizing plate can be reduced. Further, by using the antireflection film of the present invention as the outermost layer, reflection of external light and the like can be prevented, and a polarizing plate excellent in scratch resistance, antifouling property and the like can be obtained.

[Polarizing film]
As the polarizing film, a known polarizing film or a polarizing film cut out from a long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction may be used.

A long polarizing film in which the absorption axis of the polarizing film is neither parallel nor perpendicular to the longitudinal direction is produced by the following method. That is, both ends of a continuously supplied polymer film are stretched by applying a tension while being held by a holding means and stretched at least 1.1 to 20.0 times in the film width direction. The longitudinal movement speed difference of the holding device is within 3%, and the angle formed by the film traveling direction at the exit of the step of holding both ends of the film and the substantial stretching direction of the film is inclined by 20 to 70 °. It can be produced by a stretching method in which the traveling direction is bent with both ends of the film held. In particular, those inclined at 45 ° are preferably used from the viewpoint of productivity.

  The method for stretching the polymer film is described in detail in paragraphs 0020 to 0030 of JP-A-2002-86554.

(Image display device)
The image display device of the present invention uses the antireflection film or the polarizing plate on the outermost surface of the display. For example, in the aspect used as one side of the surface protective film of the polarizing film, twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically compensated bend It can be preferably used for a transmissive, reflective, or transflective liquid crystal display device in a mode such as a cell (OCB).

In VA mode liquid crystal cell,
(1) In addition to a narrowly-defined VA mode liquid crystal cell (described in JP-A-2-176625) in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied. ,
(2) Liquid crystal cell ("SID97, Digest of tech. Papers" (Preliminary Collection), Vol. 28 (1997), p. 845},
(3) A liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Procedures 58-59 (1998) ) Description) and
(4) Includes SURVAVAL mode liquid crystal cells (announced at "LCD International 98").

  For a VA mode liquid crystal cell, a polarizing plate prepared by combining a biaxially stretched triacetyl cellulose film with the antireflection film of the present invention is preferably used. As for the method for producing a biaxially stretched triacetyl cellulose film, for example, the methods described in JP-A Nos. 2001-249223 and 2003-170492 are preferably used.

  The OCB mode liquid crystal cell is a liquid crystal display device using a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between the upper part and the lower part of the liquid crystal cell. It is disclosed in the specifications of Japanese Patent Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

  In an ECB mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and is most frequently used as a color TFT liquid crystal display device, and is described in many documents. For example, it is described in “EL, PDP, LCD display” {issued by Toray Research Center (2001)}.

  Particularly for TN mode and IPS mode liquid crystal display devices, as described in JP-A-2001-100043, an optical compensation film having a viewing angle widening effect is protected on the two front and back surfaces of the polarizing film. By using it on the surface of the film opposite to the antireflection film of the present invention, a polarizing plate having an antireflection effect and a viewing angle expansion effect can be obtained with the thickness of one polarizing plate, which is particularly preferable.

  In order to describe the present invention in detail, examples will be described below, but the present invention is not limited thereto. Unless otherwise specified, “part” and “%” are based on mass.

<Preparation of antireflection film>
(Synthesis of fluorine-containing copolymer)
Synthesis Example 1: Synthesis of fluorine-containing copolymer (SP-1) having a polysiloxane segment In an autoclave with a stainless steel stirrer having an internal volume of 100 mL, 40 mL of ethyl acetate, 2.20 g of HEVE, 5.40 g of EVE, {S- 3.98 g of a polymer initiator corresponding to (1)} and 0.40 g of dilauroyl peroxide were charged, and the inside of the system was deaerated and replaced with nitrogen gas. Further, 16.5 g of hexafluoropropylene (HFP) was introduced into the autoclave and the temperature was raised to 65 ° C. The pressure when the temperature in the autoclave reached 65 ° C. was 5.4 kg / cm ² . The temperature was maintained at 65 ° C., and the reaction was continued for 10 hours. When the pressure reached 3.2 kg / cm ² , the heating was stopped and the mixture was allowed to cool. When the internal temperature dropped to room temperature, unreacted monomers were driven out, the autoclave was opened, and the reaction solution was taken out.

  The reaction solution was poured into a large excess of methanol, and the resulting polymer was dissolved in a small amount of ethyl acetate and reprecipitated twice to completely remove residual monomers. The polymer was dried under reduced pressure to obtain a fluorine-containing copolymer (SP-1) having a polysiloxane segment.

  A fluorine-containing copolymer (SP) having another polysiloxane segment useful for the present invention and a fluorine-containing copolymer (MP) having a main chain composed only of carbon atoms are synthesized in the same manner.

(Preparation of curable composition)
Examples 1-1 to 1-36 and Comparative Examples 1-1 to 1-7
[Preparation of coating solution for low refractive index layer (Ln1 to Ln36)]
Each component is mixed in the parts by mass shown in Table 3 below, dissolved in methyl ethyl ketone so as to be 6% by mass, filtered through a polypropylene filter having a pore size of 1 μm, and a coating solution for forming a low refractive index layer is obtained. Prepared.

  In Table 3, colloidal silica “MEK-ST” is “MEK-ST” (trade name) manufactured by Nissan Chemical Industries, Ltd., and curing agent “CY303” is “Cymel 303” (trade name) is Mitsui Cytec. ) Made of methylolated melamine, the curing catalyst “pTSA” represents p-toluenesulfonic acid, respectively.

[Preparation of Comparative Refractive Index Layer Coating Liquids (Lnr1 to Lnr7)]
In the same manner as in the above example, the components shown in Table 4 were mixed and dissolved with methyl ethyl ketone so as to be 6% by mass, and then filtered through a polypropylene filter having a pore size of 1 μm, for a low refractive index layer for a comparative example. A coating solution was prepared.

In Table 4, the copolymers indicated as “SPr-1” and “SPr-2” are compounds having the following structures, and were synthesized under the same conditions as described in the following patents.
SPr-1: copolymer of Example 2 described in JP-A-11-189621.
SPr-2: copolymer of Example 7 described in JP-A No. 2004-307524.
The numbers represent the mole fraction of each monomer.

[Preparation of antireflection film]
Example 11-1
[Preparation of coating liquid for hard coat layer (HC1)]
"PET-30" 50.0g
"Irgacure 184" 2.0g
"SX-350" (30%) 1.5g
Cross-linked acrylic-styrene particles (30%) 13.9g
"KBM-5103" 10.0g
Toluene 38.5g

  The mixed solution was filtered through a polypropylene filter having a pore size of 30 μm to prepare a hard coat layer coating solution (HC1).

The compounds used are shown below.
“PET-30”: a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate {manufactured by Nippon Kayaku Co., Ltd.}.
“Irgacure 184”: polymerization initiator {manufactured by Ciba Specialty Chemicals Co., Ltd.}.
“SX-350”: Cross-linked polystyrene particles having an average particle size of 3.5 μm {refractive index: 1.60, manufactured by Soken Chemical Co., Ltd., 30% toluene dispersion. Use after dispersion for 20 minutes at 10,000 rpm in a Polytron disperser}.
Cross-linked acrylic-styrene particles: average particle size 3.5 μm {refractive index 1.55, manufactured by Soken Chemical Co., Ltd., 30% toluene dispersion. Use after dispersion for 20 minutes at 10,000 rpm in a Polytron disperser}.
“KBM-5103”: acryloyloxypropyltrimethoxysilane {manufactured by Shin-Etsu Chemical Co., Ltd.}.

[Preparation of Antireflection Film (1-1)]
An 80 μm-thick triacetylcellulose film “TAC-TD80U” (manufactured by Fuji Photo Film Co., Ltd.) is unwound in a roll form, and the above hard coat layer coating solution (HC1) is directly applied to 180 lines. / In, using a micro gravure roll with a diameter of 50 mm having a gravure pattern with a depth of 40 μm and a doctor blade, applying at a gravure roll rotation speed of 30 rpm and a conveyance speed of 30 m / min, drying at 60 ° C. for 150 seconds, Using an "air-cooled metal halide lamp" {manufactured by Eye Graphics Co., Ltd.} with an oxygen concentration of 0.1% by volume under a nitrogen purge, ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 110 mJ / cm ² were irradiated. The coating layer was cured to form a 6 μm thick layer and wound up. The surface roughness of the hard coat layer thus obtained was Ra = 0.18 μm, Rz = 1.40 μm, and haze 35%.

On the hard coat layer thus obtained, using the microgravure roll with a diameter of 50 mm having a gravure pattern with a line number of 180 lines / inch and a depth of 40 μm, and a doctor blade, the low refractive index material coating solution Ln1, The coating was applied under the conditions of a gravure roll rotation speed of 30 rpm and a conveyance speed of 15 m / min, dried at 120 ° C. for 150 seconds, and further cured at 120 ° C. for 10 minutes. Thereafter, using a 240 W / cm air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) under a nitrogen purge, ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 400 mJ / cm ² were used, and a low refractive index of 95 nm was obtained. A layer was formed and wound up.

Examples 11-2 to 11-36 and Comparative Examples 11-1 to 11-7
[Preparation of Antireflection Films (1-2) to (1-36) and (1-r1) to (1-r7)]
In the production of the antireflection film (1-1) of Example 11-1, any one of (Ln2) to (Ln36) and (Lnr1) to (Lnr7) was used instead of using the coating solution for low refractive index layer (Ln1). The antireflection films (1-2) to (1-36) and comparative antireflection films (1-r1) to (1- Each of r7) was prepared.

[Saponification treatment of antireflection film]
Each of the obtained antireflection films was treated and dried under the following saponification standard conditions.
Alkaline bath: 1.5 mol / dm ³ sodium hydroxide aqueous solution, 55 ° C.-120 seconds.
First washing bath: tap water, 60 seconds.
Neutralization bath: 0.05 mol / dm ³ sulfuric acid, 30 ° C.-20 seconds.
Second washing bath: tap water, 60 seconds.
Drying: 120 ° C., 60 seconds.

[Evaluation of antireflection film]
The following evaluation was performed using the saponified antireflection film thus obtained.

(Evaluation 1) Measurement of average reflectance Using a spectrophotometer "V-550" {manufactured by JASCO Corporation}, spectral reflectance at an incident angle of 5 ° using an integrating sphere in a wavelength range of 380 to 780 nm. Was measured. In the evaluation of the spectral reflectance, an average reflectance of 450 to 650 nm was used.

After the back surface of the antireflection film was roughened, it was light-absorbed with black ink (transmittance at 380 to 780 nm was less than 10%) and measured on a black table.
In addition, the sample processed into the polarizing plate mentioned later measured using the thing of a polarizing plate form as it is. In the case of a display device that does not use a polarizing plate, the back surface of the antireflection film is roughened and then light-absorbed with black ink (transmittance at 380 to 780 nm is less than 10%). Measured on a table.

(Evaluation 2) Steel Wool Scratch Resistance Evaluation A rubbing test was performed using a rubbing tester under the following conditions.
Evaluation environmental conditions: 25 ° C., 60% RH.
Rubbing material: Steel wool {"No. 0000" made by Nippon Steel Wool Co., Ltd.} was wound around the rubbing tip (1 cm x 1 cm) of a tester that was in contact with the sample, and the band was fixed so as not to move. Then, the reciprocating rubbing motion under the following conditions was given.
Moving distance (one way): 13 cm, rubbing speed: 13 cm / sec.
Load: 200 g / cm ² , tip contact area: 1 cm × 1 cm.
Number of rubs: 10 round trips.

An oil-based black ink was applied to the back side of the rubbed sample and visually observed with reflected light, and scratches on the rubbed portion were evaluated according to the following criteria.
○: Even if you look very carefully, no scratches are visible.
○ △: Slightly weak scratches are visible when viewed very carefully.
Δ: Weak scratches are visible.
Δ ×: moderate scratches are visible.
X: There is a scratch that can be seen at first glance.

(Evaluation 3) Eraser rubbing scratch resistance evaluation A rubbing test was performed using a rubbing tester under the following conditions.
Evaluation environmental conditions: 25 ° C., 60% RH.
Rubbing material: A plastic eraser {"MONO" manufactured by Dragonfly Pencil Co., Ltd.) was fixed to the tip (1 cm x 1 cm) of the rubbing tester in contact with the sample.
Moving distance (one way): 4 cm, rubbing speed: 2 cm / sec, load: 500 g / cm ² , tip contact area: 1 cm × 1 cm.
Number of rubs: 100 round trips.

An oil-based black ink was applied to the back side of the rubbed sample and visually observed with reflected light, and scratches on the rubbed portion were evaluated according to the following criteria.
○: Even if you look very carefully, no scratches are visible.
○ △: Slightly weak scratches are visible when viewed very carefully.
Δ: Weak scratches are visible.
Δ ×: moderate scratches are visible.
X: There is a scratch that can be seen at first glance.
XX: Single-sided film is damaged.

(Evaluation 4) “Magic Ink” Adhesion Evaluation As an index of surface contamination resistance, an antireflection film was conditioned at a temperature of 25 ° C. and 60% RH for 2 hours, and then “magic ink” (trade name) was applied to the sample surface. ) Was attached, and then the state when it was wiped off with a cleaning cloth was observed, and the magic adhesion was evaluated as follows.
A: The mark of “magic ink” can be completely wiped off.
○: A trace of “magic ink” is visible.
Δ: A trace of “magic ink” is visible.
X: Traces of “magic ink” are hardly wiped off.

  The evaluation results are shown in Table 5.

  As is clear from this example, it can be seen that the antireflection film obtained by the present invention has sufficiently strong film strength and slipperiness, and thus has excellent scratch resistance. In addition, since the fluorine content is high and the film surface has excellent leveling properties, it has a very low surface reflectance in a wide wavelength region, and maintains the same surface reflectance as that of the comparative example. I understand that. Furthermore, the antifouling property is also greatly improved.

Example 12-1
The multilayer antireflection film shown below was produced.

[Preparation of coating liquid for hard coat layer (HC2)]
“Desolite Z7404” {Hardcoat composition liquid containing zirconia fine particles: JSR Corporation
100 parts by mass, "DPHA" {UV curable resin: Nippon Kayaku Co., Ltd.} 31 parts by mass, "KBM-5103" {Silane coupling agent: Shin-Etsu Chemical Co., Ltd.} 10 parts by mass, 29 parts by mass of methyl ethyl ketone (MEK), 13 parts by mass of methyl isobutyl ketone (MIBK), and 5 parts by mass of cyclohexanone were put into a mixing tank and stirred to obtain a hard coat layer coating solution (HC2).

[Preparation of antireflection film (2-1)]
As a support, a triacetyl cellulose film “TACTD80U” (manufactured by Fuji Photo Film Co., Ltd.) was unwound in a roll form, and the above hard coat layer coating solution (HCL-2) was coated with 135 lines / inch, Using a microgravure roll having a diameter of 60 μm and a doctor blade having a gravure pattern of 60 μm in depth, the coating was performed at a conveyance speed of 10 m / min, drying at 60 ° C. for 150 seconds, and further 160 W / cm under a nitrogen purge. Using an “air-cooled metal halide lamp” {manufactured by Eye Graphics Co., Ltd.}, the coating layer is cured by irradiating with ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 100 mJ / cm ² , forming a hard coat layer, and winding It was. The hard coat layer was prepared by adjusting the rotational speed of the gravure roll so that the thickness of the hard coat layer after curing was 4.0 μm.

On the hard coat layer thus obtained, using the microgravure roll with a diameter of 50 mm having a gravure pattern with a line number of 180 lines / inch and a depth of 40 μm, and a doctor blade, the low refractive index material coating solution Ln1, The coating was applied under the conditions of a gravure roll rotation speed of 30 rpm and a conveyance speed of 15 m / min, dried at 120 ° C. for 150 seconds, and further cured at 120 ° C. for 10 minutes. Thereafter, using a 240 W / cm air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) under a nitrogen purge, ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 400 mJ / cm ² were used, and a low refractive index of 95 nm was obtained. A layer was formed and wound up.

  When evaluated according to Example 11, the same effect was obtained by using the antireflection film of the present invention.

<Preparation of polarizing plate with antireflection film>
Example 21
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. Each antireflection film (1-1) to (1-36) produced in Example 11 was saponified in the same manner as in Example 11, and a polyvinyl alcohol adhesive was used to support the antireflection film. Each was attached to one side of the polarizing film such that the (triacetylcellulose) side was the polarizing film side. A viewing angle widening film “wide view film SA12B” (manufactured by Fuji Photo Film Co., Ltd.) having an optical compensation layer was saponified and pasted on the other side of each polarizing film using a polyvinyl alcohol adhesive. . Thus, each polarizing plate was produced. As a result of performing the evaluation according to Example 11 in this polarizing plate state, the same effect was obtained by using the antireflection film of the present invention.

<Production of image display device>
Example 31
When each antireflection film sample of Examples 11 and 12 and each polarizing plate sample of Example 21 were bonded to the glass plate on the surface of the organic EL display device via an adhesive, both were on the glass surface. Reflection was suppressed, and a display device with high visibility was obtained.

Fig.1 (a) is a cross-sectional schematic diagram which shows the layer structure of one Embodiment in the antireflection film of this invention. FIG.1 (b) is a cross-sectional schematic diagram which shows the layer structure of another embodiment in the antireflection film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a: Antireflection film 1b: Antireflection film 2: Transparent support 3: Hard coat layer 4: Anti-glare hard coat layer 5: Low refractive index layer 7: Medium refractive index layer 8: High refractive index layer

Claims (8)

  A fluorine-containing copolymer having a polysiloxane segment in the main chain and a fluorine-containing copolymer having a main chain composed of only carbon atoms, respectively, and having a polysiloxane segment in the main chain A film-forming composition, wherein the content of the polymer is 30% by mass or less based on the total amount of the fluorine-containing copolymer. The film forming composition according to claim 1, wherein the fluorine-containing copolymer having a polysiloxane segment in the main chain includes a structure represented by the following general formula (1).
General formula (1):

In the general formula (1), Rf ¹¹ represents a perfluoroalkyl group having 1 to 5 carbon atoms, Rf ¹² represents a fluorine-containing alkyl group having 1 to 30 carbon atoms, A represents a hydroxyl group-containing vinyl monomer polymerization unit, B Represents an optional component, and R ¹¹ and R ¹² may be the same or different and each represents an alkyl group or an aryl group. a1 to e1 each represent a mole fraction (%) of each constituent component, and relationships of 0 <a1 <50, 0 ≦ b1 ≦ 40, 0 <c1 ≦ 10, 0 ≦ d1 <50, 10 ≦ e1 <100, respectively. Meet. The film-forming composition according to claim 1, wherein the fluorine-containing copolymer whose main chain is composed only of carbon atoms includes a structure represented by the following general formula (2).
General formula (2):

In the general formula (2), Rf ¹¹ represents a perfluoroalkyl group having 1 to 5 carbon atoms, Rf ¹² represents a fluorine-containing alkyl group having 1 to 30 carbon atoms, A represents a hydroxyl group-containing vinyl monomer polymerization unit, B Represents an optional component. a2 to d2 each represent a mole fraction (%) of each constituent component, and satisfy the relationships of 30 ≦ a2 ≦ 70, 0 ≦ b2 ≦ 40, 0 <c2 ≦ 70, and 0 ≦ d2 ≦ 40, respectively.   The film-forming composition according to claim 2 or 3, wherein the film-forming composition further comprises a crosslinking agent capable of reacting with a hydroxyl group contained in any of the fluorine-containing copolymers.   The composition for film formation according to any one of claims 1 to 4, wherein the composition for film formation further contains inorganic fine particles.   An antireflection film having a low refractive index layer on a transparent support, wherein the low refractive index layer is formed from the film forming composition according to any one of claims 1 to 5. Antireflection film.   The antireflection film according to claim 6 is used for one of two protective films of a polarizing film in a polarizing plate.   An anti-reflection film according to claim 6 or a polarizing plate according to claim 7 is used on the outermost surface of a display.

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