JP2014114432A - Composition for forming hard coat layer, and hard coat layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coat layer with high hardness, and excellent scratch resistance and impact resistance.SOLUTION: An aqueous composition contains inorganic particles with an average aspect ratio of 30-5000, and a polymerizable monomer. The proportion of the inorganic particles to the total solid content in the aqueous composition is 25-65 mass%.

Description

  The present invention relates to a composition for forming a hard coat layer, a hard coat layer, and a laminated film. Specifically, the present invention includes inorganic particles having an average aspect ratio of 30 to 5000 and a polymerizable monomer, and the proportion of the inorganic particles to the total solid content in the aqueous composition is 25 to 65% by mass. It relates to an aqueous composition. Moreover, this invention relates to the laminated film containing the laminated body which laminated | stacked the hard-coat layer formed from this aqueous composition, and the hard-coat layer containing a specific inorganic particle on this hard-coat layer.

  In recent years, display devices such as a liquid crystal display, a plasma display, and a touch panel display are rapidly spreading. Since the surfaces of these display devices come into contact with various objects, they are easily damaged. Also, sometimes a strong impact is applied. For this reason, the surface of a display device is required to have high scratch resistance and impact resistance.

In order to give high scratch resistance and impact resistance to the surface of the display device, a hard coat layer is often provided on the surface layer of the display device. The hard coat layer is formed by curing a material containing a polyfunctional acrylic polymerizable monomer or oligomer by irradiating with ultraviolet rays or electron beams, or condensing and hydrolyzing a hydrolyzate of alkoxysilane.
For example, Patent Document 1 discloses a hard coat film in which a hard coat layer is coated on a transparent substrate film. Here, in order to increase the hardness of the hard coat layer, inorganic fine particles having an average aspect ratio of 1.5 to 20 are included. In Patent Document 1, an organic solvent is used as a solvent for the hard coat layer forming composition.

  Patent Document 2 discloses an alumina porous membrane using alumina particles having an average aspect ratio of 30 to 5000. The alumina porous film disclosed in Patent Document 2 is a film-like structure having both light emitting ability and intensity by ultraviolet excitation. In this film-like structure, inorganic particles having a high aspect ratio are used, but a binder such as a resin and an alkoxysilane mixed when a normal hard coat layer is formed is not contained.

JP 2002-60526 A JP 2010-105846 A

As described above, the hard coat layer described in Patent Document 1 contains inorganic fine particles having an average aspect ratio of 1.5 to 20, but the hardness thereof is not sufficient. For this reason, a hard coat layer with higher hardness and excellent scratch resistance has been demanded.
Moreover, since the composition for hard-coat layer formation of patent document 1 uses the organic solvent as a solvent, the load to an environment is large, and the deterioration of the manufacturing environment by the organic solvent volatilizing in a manufacturing process becomes a problem. It was.

  Moreover, in patent document 2, although the alumina porous film | membrane is formed using the alumina particle whose average aspect-ratio is 30-5000, since it did not contain a binder, it was difficult to form a thick film. . For this reason, the alumina porous membrane disclosed in Patent Document 2 has a problem that it is vulnerable to impact. Furthermore, since the binder is not contained in the coating liquid, a process of heating to a high temperature of about 1000 ° C. is required at the time of film formation, and there is a problem that the production suitability is poor.

  In order to solve the problems of the prior art, the inventors of the present application have studied for the purpose of providing a hard coat layer having high hardness and excellent scratch resistance and impact resistance. Advanced. The inventors of the present application have also studied for the purpose of forming a hard coat layer by a method having low environmental burden and excellent manufacturing suitability.

As a result of diligent studies to solve the above problems, the inventors of the present application made a hard coat layer from an aqueous composition containing inorganic particles (inorganic filler) having an average aspect ratio of 30 to 5000 and a polymerizable monomer. It was found that a hard coat layer having high hardness and excellent scratch resistance and impact resistance can be obtained by forming. Furthermore, the inventors of the present invention succeeded in reducing the environmental burden and improving the production suitability by using an aqueous composition as the coating liquid for forming the hard coat layer, and completed the present invention.
Specifically, the present invention has the following configuration.

[1] An aqueous composition containing inorganic particles and a polymerizable monomer, wherein the inorganic particles have an average aspect ratio of 30 to 5000, and the proportion of the inorganic particles to the total solid content in the aqueous composition Is an aqueous composition, characterized in that it is 25 to 65% by mass.
[2] The aqueous composition according to [1], wherein the inorganic particles have an average aspect ratio of 300 to 800.
[3] The aqueous composition according to [1] or [2], wherein the ratio of the inorganic particles to the total solid content in the aqueous composition is 30 to 60% by mass.
[4] The aqueous composition according to any one of [1] to [3], wherein the polymerizable monomer is an alkoxysilane.
[5] The aqueous composition according to [4], wherein the alkoxysilane is a mixture of tetraalkoxysilane and alkyltrialkoxysilane.
[6] The aqueous composition according to any one of [1] to [5], further comprising a curing accelerator.
[7] The aqueous composition according to [6], wherein the curing accelerator is an aluminum chelate complex.
[8] A hard coat layer formed by curing the aqueous composition according to any one of [1] to [7].
[9] An average aspect ratio of 1 to 1 is formed on the first hard coat layer formed by curing the aqueous composition according to any one of [1] to [7] and the first hard coat layer. Including a laminate in which a second hard coat layer containing 10 inorganic particles is laminated,
The difference in the content of the inorganic particles contained in the first hard coat layer and the second hard coat layer is 10% or less.
[10] The laminated film according to [9], wherein the average particle diameter of the inorganic particles contained in the second hard coat layer is 50 nm or less.
[11] The laminated film according to [9] or [10], wherein the haze value is 1% or less.
[12] A support is further provided, and the support is provided on one surface side of the first hard coat layer and on the side opposite to the surface on which the second hard coat layer is laminated. The laminated film according to any one of [9] to [11], wherein
[13] The laminated film according to [12], wherein an easy adhesion layer is further provided between the support and the first hard coat layer.
[14] The laminated film according to any one of [9] to [13], wherein the total of the average film thicknesses of the first hard coat layer and the second hard coat layer is 2 μm or more.
[15] An aqueous composition comprising inorganic particles having an average aspect ratio of 30 to 5000 and a polymerizable monomer, wherein the aqueous composition accounts for 25 to 65% by mass of the inorganic particles with respect to the total solid content A step of coating the body and forming a first hard coat layer, wherein the step of forming the first hard coat layer includes a step of heating at 120 to 300 ° C. A method for producing a laminated film.
[16] The method for producing a laminated film according to [15], wherein the heating is performed at 120 to 300 ° C. for 10 seconds to 1 hour.
[17] After the step of forming the first hard coat layer, the step of forming a second hard coat layer is further included, and the step of forming the second hard coat layer includes an average aspect ratio. Of the laminated film according to [15] or [16], which comprises a step of applying an aqueous composition comprising inorganic particles of 1 to 10 and a polymerizable monomer on the first hard coat layer. Production method.
[18] A laminated film produced by the production method according to any one of [15] to [17].

  According to the present invention, a hard coat layer with high hardness can be obtained, and the scratch resistance of the hard coat layer can be improved. Furthermore, the hard coat layer obtained by the present invention is not easily broken and has excellent impact resistance.

  In addition, according to the present invention, since a hard coat layer can be formed from an aqueous composition, the burden on the environment can be reduced. Furthermore, according to the present invention, since the heating temperature during film formation can be set low, the production of the hard coat layer can be facilitated, and the production suitability can be enhanced. Furthermore, the cost concerning manufacture of a hard-coat layer can be suppressed.

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

(Aqueous composition)
The aqueous composition of the present invention contains inorganic particles having an average aspect ratio of 30 to 5,000 and a polymerizable monomer. The ratio of the inorganic particles to the total solid content in the aqueous composition is 25 to 65% by mass. A hard coat layer is formed by applying the aqueous composition described above onto a support and curing it. That is, the aqueous composition of the present invention can be an aqueous composition for forming a hard coat layer.

In the present invention, by including inorganic particles having an average aspect ratio of 30 to 5000 and a polymerizable monomer, the hardness can be increased when the hard coat layer is formed, and the scratch resistance and impact resistance can be further increased. Can do. In the present invention, the thickness of the hard coat layer can be increased by mixing high aspect ratio inorganic particles having an average aspect ratio of 30 to 5,000 and a polymerizable monomer. Thereby, the hardness of a hard-coat layer can be raised more.
Since the hard coat layer obtained by the present invention has excellent scratch resistance and impact resistance in addition to high hardness, it is suitably used for display devices such as touch panels.

  In this invention, the heating temperature at the time of film-forming of a hard-coat layer can be made low by mixing an inorganic particle with an average aspect-ratio of 30-5000, and a polymerizable monomer. Thereby, the manufacturing efficiency of a hard-coat layer can be improved and the cost concerning manufacture can be reduced.

  Moreover, since the aqueous composition of this invention does not use the organic solvent, what evaporates when apply | coating and drying an aqueous composition becomes a water component mainly. For this reason, compared with the case where an organic solvent is used, the load to an environment can be reduced significantly.

(Inorganic particles)
The aqueous composition of the present invention contains inorganic particles. The inorganic particles have a high aspect ratio, and the average aspect ratio is 30 to 5000. The aspect ratio of the inorganic particles may be 30 or more, preferably 100 or more, more preferably 200 or more, and further preferably 300 or more. The aspect ratio of the inorganic particles may be 5000 or less, preferably 3000 or less, more preferably 1500 or less, and still more preferably 800 or less. For example, 350-750 etc. are mentioned.
In the present invention, a hard coat layer with higher hardness can be formed by setting the average aspect ratio of the inorganic particles within the above range.

  Here, the average aspect ratio is the average minor axis of the inorganic particles in the thickness direction perpendicular to the major axis direction of the inorganic particles, r (nm), and the average major axis of the inorganic particles in the major axis direction of the inorganic particles is L (nm). ) Means the L / r ratio. That is, the aspect ratio can be calculated by observing inorganic particles contained in the aqueous composition and dividing the major axis of the inorganic particles by the minor axis.

  In the present invention, the average minor axis r (nm) of the inorganic particles is preferably 1 to 20 nm. The average minor axis r (nm) is preferably 1 nm or more, and more preferably 2 nm or more. The average minor axis r (nm) is preferably 20 nm or less, more preferably 15 nm or less, and further preferably 10 nm or less. Moreover, it is preferable that average major axis L (nm) is 100-10000 nm. The average major axis L (nm) is preferably 100 nm or more, more preferably 300 nm or more, and further preferably 700 nm or more. The average major axis L (nm) is preferably 10,000 nm or less, more preferably 8000 nm or less, and further preferably 5000 nm or less. By setting the minor axis and the major axis of the inorganic particles within the above ranges, the average aspect ratio of the inorganic particles can be within a preferable range.

  The length of the inorganic particles described above can be measured using an optical microscope or an electron microscope. For example, using a scanning electron microscope (SEM), select 100 arbitrary inorganic particles having a major axis of 100 nm or more present in a cross section perpendicular to the longitudinal direction of the hard coat layer and a cross section parallel to the longitudinal direction. The aspect ratio can be obtained by measuring the major axis and minor axis of the inorganic particles. The major axis and minor axis are measured for every 100 inorganic particles, and the average aspect ratio can be calculated from these aspect ratios.

The inorganic particles are not particularly limited as long as the average aspect ratio is 30 to 5000, but are preferably inorganic oxide particles having high hardness and Mohs hardness of 6 or more. For example, silicon dioxide particles, titanium dioxide particles, zirconium oxide particles, aluminum oxide particles and the like are used, and aluminum oxide particles are preferably used. Among these, alumina hydrate particles or alumina particles having a fibrous or needle-like shape are particularly suitable. The alumina hydrate particles are preferably at least one selected from amorphous, boehmite or pseudoboehmite, and more preferably boehmite or pseudoboehmite. Here, boehmite is a crystal of alumina hydrate represented by Al ₂ O ₃ .nH ₂ O (n = 1 to 1.5). Pseudoboehmite refers to a colloidal aggregate of boehmite. The crystal system of alumina particles that can be used as inorganic particles is preferably at least one selected from γ, θ, or α, and more preferably selected from γ or θ. Commercially available products include, for example, boehmite sol (manufactured by Kawaken Fine Chemical Co., Ltd.), AS-520 (manufactured by Nissan Chemical Co., Ltd.), Quartron (manufactured by Fuso Chemical Co., Ltd.), and AKP series (manufactured by Sumitomo Chemical Co., Ltd.). From these, those having an average aspect ratio and a crystal system of alumina particles within the scope of the present invention can be used.

The alumina hydrate particles or alumina particles are preferably dispersed in an aqueous solution. Alumina hydrate particles or an aqueous solution in which alumina particles are dispersed is called an aqueous alumina sol, and this aqueous alumina sol can be produced by hydrolyzing a hydrolyzable aluminum compound and forming a colloid under acidic conditions. . The hydrolyzable aluminum compound includes various inorganic aluminum compounds and aluminum compounds having an organic group. Examples of the inorganic aluminum compound include salts of inorganic acids such as aluminum chloride, aluminum sulfate, and aluminum nitrate, aluminates such as sodium aluminate, and aluminum hydroxide.
Examples of the aluminum compound having an organic group include carboxylates such as aluminum acetate, aluminum ethoxide, aluminum isopropoxide, aluminum n-butoxide, aluminum sec-butoxide, and other aluminum alkoxides, cyclic aluminum oligomers, Illustrative are aluminum chelates such as propoxy (ethylacetoacetate) aluminum and tris (ethylacetoacetate) aluminum, and organoaluminum compounds such as alkylaluminum.

Among these compounds, aluminum alkoxides are preferable and those having an alkoxyl group having 2 to 5 carbon atoms are particularly preferable because they have moderate hydrolyzability and easy removal of by-products.
As the acid used for the hydrolysis, monovalent acids such as hydrochloric acid, nitric acid, formic acid, acetic acid, propionic acid and butyric acid are preferable, and acetic acid is particularly preferably used in terms of operability and economy. The usage-amount of an acid is 0.2-2.0 mol times with respect to aluminum alkoxide, Preferably it is 0.3-1.8 mol times. By making the usage-amount of the acid used for a hydrolysis into the said range, the average aspect-ratio of the particle | grains obtained can be made into a desired range, and stability with time can be improved. In addition, it is preferable to perform a hydrolysis at 100 degrees C or less for 0.1 to 3 hours.

  2-15 mass% is preferable, and, as for the solid content concentration of the acid aqueous solution of the aluminum alkoxide to hydrolyze, Preferably it is 3-10 mass%. By setting the solid content concentration within the above range, the average aspect ratio of the obtained particles can be set to a desired range, and the stirrability of the reaction liquid can be enhanced.

  After the alcohol produced by hydrolysis is distilled off, peptization is performed. The peptization treatment is performed at 100 to 200 ° C. for 0.1 to 10 hours, more preferably at 110 to 180 ° C. for 0.5 to 5 hours. In this way, inorganic particles having a desired average aspect ratio can be obtained.

  In the hard coat layer obtained in the present invention, it is preferable that the long axis direction of the inorganic particles having an average aspect ratio of 30 to 5000 is stacked and accumulated in a state of being oriented in parallel, so that the inorganic particles form a bundle structure. It is more preferable that they are stacked. In order to accumulate inorganic particles in such a manner, the inorganic particles are preferably dispersed uniformly in the aqueous composition. The accumulation state can also be adjusted by adjusting the film formation conditions of the hard coat layer and the pH of the aqueous composition.

  In the present invention, the pH of the aqueous composition is preferably 2 to 7, more preferably 2 to 6, further preferably 2 to 5, and particularly preferably 3 to 4. In order to set the pH of the aqueous composition within the above range, it is preferable to add an acid such as acetic acid, hydrochloric acid, nitric acid, formic acid, propionic acid, butyric acid to the aqueous composition. Among them, it is particularly preferable to add acetic acid, and it is most preferable to adjust the pH to 3 to 4 by adding acetic acid. By setting the pH of the aqueous composition as described above, the inorganic particles can be stacked and accumulated in a state in which the long axis direction of the inorganic particles is oriented in parallel while enhancing the dispersibility of the inorganic particles. Thereby, it is possible to form a hard coat layer having a uniform film thickness and a high hardness. Furthermore, by accumulating the inorganic particles in a state where the major axis directions are oriented in parallel, it is possible to obtain a hard coat layer that is hard to be damaged and is resistant to impact.

  The ratio of the inorganic particles to the total solid content in the aqueous composition may be 25% by mass or more, preferably 28% by mass or more, and more preferably 30% by mass or more. The proportion of inorganic particles may be 65% by mass or less, preferably 60% by mass or less, more preferably 55% by mass or less, and further preferably 50% by mass or less. It is especially preferable that it is 40 mass% or less. Two or more kinds of inorganic particles may be used in combination, and in this case, the total amount of all kinds used is within the above range. By making the ratio which an inorganic particle accounts in the said range, the dispersibility of the inorganic particle in an aqueous composition can be improved. Furthermore, a hard coat layer having high hardness and excellent scratch resistance and impact resistance can be formed.

(Polymerizable monomer)
The aqueous composition of the present invention contains a polymerizable monomer. Here, the polymerizable monomer means a compound that can form an oligomer by polymerization of the monomers. The polymerizable monomer is preferably an alkoxysilane. As the alkoxysilane, it is preferable to use a water-soluble or water-dispersible material. The use of a water-soluble or water-dispersible material is particularly preferable from the viewpoint of reducing environmental pollution caused by VOC (volatile organic compounds).

  Alkoxysilane has a hydrolyzable group. Silanol is generated by hydrolyzing the hydrolyzable group in an acidic aqueous solution, and an oligomer is generated by condensation between the silanols. In the aqueous composition of the present invention, a part of the alkoxysilane may be hydrolyzed.

  It is preferable that 40-70 mass% of a polymerizable monomer is contained with respect to the aqueous composition total mass. The content of the polymerizable monomer is preferably 40% by mass or more, more preferably 45% by mass or more, and more preferably 50% by mass or more. Moreover, it is preferable that the content rate of a polymerizable monomer is 70 mass% or less, and it is more preferable that it is 65 mass% or less. Two or more polymerizable monomers may be used in combination, and in that case, the total amount of all kinds used is within the above range. By setting the content of the polymerizable monomer within the above range, the temporal stability of the aqueous composition can be increased, and the hardness when the hard coat layer is formed can be increased. Furthermore, it is possible to increase the thickness of the hard coat layer.

  The alkoxysilane preferably contains tetraalkoxysilane, more preferably a mixture of tetraalkoxysilane and alkyltrialkoxysilane. When the alkoxysilane contains tetraalkoxysilane, which is a tetrafunctional alkoxysilane, sufficient hardness can be obtained when the hard coat layer is formed. In addition, by mixing alkyltrialkoxysilane, which is a trifunctional alkoxysilane, moderate flexibility can be imparted while maintaining the hardness of the hardcoat layer high, and a hardcoat layer that is more difficult to crack is obtained. be able to.

  When the alkoxysilane is a mixture of tetraalkoxysilane and alkyltrialkoxysilane, the molar ratio of tetraalkoxysilane and alkyltrialkoxysilane is preferably 0: 100 to 85:15, 5:95 to 80: 20 is more preferable, and 10:90 to 75:25 is even more preferable. By setting the molar ratio within the above range, a hard coat layer having high hardness and excellent scratch resistance and impact resistance can be obtained.

  As the tetraalkoxysilane, those having 1 to 4 carbon atoms of each alkoxy group are more preferably used. Among these, tetraalkoxysilane is particularly preferably tetramethoxysilane or tetraethoxysilane. By setting the number of carbon atoms of each alkoxy group to 4 or less, the hydrolysis rate of the tetrafunctional alkoxysilane when mixed with acidic water is not too slow, and the time required for dissolution until a uniform aqueous solution is obtained. Shorter. Thereby, the manufacturing efficiency at the time of manufacturing a hard-coat layer can be improved. Examples of commercially available products include KBE-04 (manufactured by Shin-Etsu Chemical Co., Ltd.).

The alkyltrialkoxysilane is a trifunctional alkoxysilane represented by the following general formula (1).
RSi (OR ¹ ) ₃ (1)
Here, R is an organic group having 1 to 15 carbon atoms not containing an amino group, and R ¹ is an alkyl group having 4 or less carbon atoms such as methyl and ethyl groups.

The alkyltrialkoxysilane represented by the general formula (1) does not contain an amino group as a functional group. That is, this alkyltrialkoxysilane has an organic group R having no amino group. When R has an amino group, if it is mixed with tetraalkoxysilane and hydrolyzed, dehydration condensation will be promoted between the produced silanols. For this reason, an aqueous composition becomes unstable and is not preferable.
R in the general formula (1) may be an organic group having a molecular chain length that has 1 to 15 carbon atoms. By setting the number of carbon atoms to 15 or less, the flexibility of the hard coat layer is not excessively increased and sufficient hardness can be obtained.

  Furthermore, the organic group represented by R preferably has a heteroatom such as oxygen, nitrogen, or sulfur. In particular, it is preferable that an epoxy group, an amide group, a urethane group, a urea group, an ester group, a hydroxy group, a carboxyl group, and the like are in the organic group R. Among them, an alkyltrialkoxysilane containing an epoxy group is particularly preferable because it has an effect of increasing the stability of silanol in acidic water. Moreover, the alkyl trialkoxysilane containing an epoxy group can provide sufficient hardness while imparting appropriate flexibility to the hard coat layer.

R ¹ in the general formula (1) is an alkyl group having 4 or less carbon atoms. Among these, R ¹ is particularly preferably a methyl group or an ethyl group. By making R ¹ an alkyl group having 4 or less carbon atoms, the hydrophilicity of the trifunctional or bifunctional alkoxysilane can be increased, and hydrolysis in an aqueous solution can be promoted.

  Among the alkyltrialkoxysilanes used in the present invention, preferred compounds are vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, and 3-ureidopropyl. Trimethoxysilane, propyltrimethoxysilane, phenyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltriethoxysilane, 3- Acryloxypropyltriethoxysilane, 3-chloropropyltriethoxysilane, 3-ureidopropyltriethoxysilane, propyltriethoxysilane, phenyltriethoxysilane, 2- ( , May be mentioned 4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl triethoxysilane. Among them, the alkyltrialkoxysilane is preferably 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, or a mixture thereof. Examples of commercially available products include KBE-403 (manufactured by Shin-Etsu Chemical Co., Ltd.).

As the polymerizable monomer, a known curable resin can be used in addition to the alkoxysilane described above. Known curable resins include thermosetting resins and activated energy ray polymerization resins.
A thermosetting resin is a resin that cures when heated. Some thermosetting resins utilize a cross-linking reaction of prepolymers such as melamine resins, urethane resins, and epoxy resins. Examples of thermosetting resins include polyester resins containing carboxyl (—COOH) groups and / or hydroxyl (—OH) groups, epoxy resins, polyacrylate resins, polymethacrylate resins, polyamide resins, fluororesins, polyimide resins, polyurethane resins. And alkyd resins.

  The active energy ray polymerizable resin is formed by applying a coating solution containing a polyfunctional monomer and a polymerization initiator and polymerizing the polyfunctional monomer with active energy rays. Examples of the functional group possessed by the monomer include a polymerizable unsaturated double bond group. Examples of the polymerizable unsaturated double bond include an acrylate group, a methacrylate group, and a vinyl group. From the viewpoint of reactivity, an acrylate group is preferably used.

  As the active energy ray, radiation, gamma ray, alpha ray, electron beam, ultraviolet ray and the like can be used, and ultraviolet ray (UV) is preferably used. Examples of the UV curable resin include acrylic resins made of acrylate monomers, epoxy resins, and urethane resins.

(Curing accelerator)
The aqueous composition of the present invention preferably further contains a curing accelerator. The curing accelerator is preferably water-soluble. The curing accelerator used in the present invention functions to promote the formation of siloxane bonds by promoting dehydration condensation of silanol in the aqueous composition. As the curing accelerator, a water-soluble inorganic acid, organic acid, organic acid salt, inorganic acid salt, metal alkoxide, or metal complex can be used. As the metal complex, a metal complex composed of Al, Mg, Mn, Ti, Cu, Co, Zn, Hf and Zr is preferable, and these can be used in combination.

  Examples of the inorganic acid include boric acid, phosphoric acid, hydrochloric acid, nitric acid, and sulfuric acid, and examples of the organic acid include acetic acid, formic acid, oxalic acid, citric acid, malic acid, and ascorbic acid. Organic acid salts include aluminum acetate, aluminum oxalate, zinc acetate, zinc oxalate, magnesium acetate, magnesium oxalate, zirconium acetate, zirconium oxalate, and inorganic acid salts include aluminum chloride, aluminum sulfate, nitric acid Examples include aluminum, zinc chloride, zinc sulfate, zinc nitrate, magnesium chloride, magnesium sulfate, magnesium nitrate, zirconium chloride, zirconium sulfate, and zirconium nitrate. Examples of the metal alkoxide include aluminum alkoxide, titanium alkoxide, and zirconium alkoxide. Examples of metal complexes include aluminum such as ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetyl acetate bis (ethyl acetoacetate), aluminum tris (acetylacetonate), etc. Chelate compounds, magnesium chelate compounds such as ethyl acetoacetate magnesium monoisopropylate, magnesium bis (ethylacetoacetate), alkyl acetoacetate magnesium monoisopropylate, magnesium bis (acetylacetonate), zirconium tetraacetylacetonate, zirconium tributoxyacetyl Acetonate, zirconium acetylacetonate bis Ethylacetoacetate), manganese acetylacetonate, cobalt acetylacetonate, copper acetylacetonate, titanium acetylacetonate and titanium oxy acetylacetonate. Of these, aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), magnesium bis (acetylacetonate), magnesium bis (ethylacetoacetate), and zirconium tetraacetylacetonate are preferred, and storage stability Considering availability, aluminum tris (acetylacetonate) and aluminum tris (ethylacetoacetate), which are aluminum chelate complexes, are particularly preferable. Examples of commercially available products include aluminum chelate A (W) (manufactured by Kawaken Fine Chemical Co., Ltd.).

  The curing accelerator is preferably mixed and dissolved uniformly in the coating solution, and is preferably dissolved in water as a solvent for the coating solution in the present invention. This is because when the solubility in water is low, it exists as a solid in the coating solution, so that it remains as a foreign substance even after coating and drying, resulting in a hard coat layer with low transparency.

  The addition amount of the curing accelerator is preferably 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, and 1 to 8% by weight with respect to all alkoxysilanes. Is more preferable. By setting the addition amount of the curing accelerator within the above range, the reaction rate of dehydration condensation of silanol can be set to an appropriate rate, and a hard coat layer having a uniform film thickness can be obtained.

(Other additives)
A surfactant may be added to the aqueous composition of the present invention for the purpose of improving the smoothness of the hard coat layer and reducing the friction on the coating surface. Further, the hard coat layer may be colored by dispersing pigments, dyes, and other fine particles. Furthermore, for the purpose of improving the weather resistance, an ultraviolet absorber, an antioxidant or the like may be added.

(Surfactant)
Various surfactants may be added to the aqueous composition of the present invention from the viewpoint of further improving coatability. As the surfactant, various surfactants such as a fluorine-based surfactant, a nonionic surfactant, a cationic surfactant, an anionic surfactant, and a silicone-based surfactant can be used.

  Examples of the fluorosurfactant include Megafac F171, F172, F173, F176, F176, F177, F141, F142, F143, F144, R30, F437, F475, F479, F482, F554, F780, F780, F781 (above DIC Corporation), Florard FC430, FC431, FC171 (above, Sumitomo 3M Limited), Surflon S-382, SC-101, Same SC-103, Same SC-104, Same SC-105, Same SC1068, Same SC-381, Same SC-383, Same S393, Same KH-40 (manufactured by Asahi Glass Co., Ltd.), PF636, PF656, PF6320 PF6520, PF7002 (manufactured by OMNOVA), and the like.

  Specific examples of nonionic surfactants include glycerol, trimethylolpropane, trimethylolethane, and ethoxylates and propoxylates thereof (for example, glycerol propoxylate, glycerin ethoxylate, etc.), polyoxyethylene lauryl ether, polyoxyethylene Stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate, sorbitan fatty acid ester (Pluronic L10, L31, L61, L62 manufactured by BASF, 10R5, 17R2, 25R2, Tetronic 304, 701, 704, 901, 904, 150R1, Pi Nin D-6512, D-6414, D-6112, D-6115, D-6120, D-6131, D-6108-W, D-6112-W, D-6115-W, D-6115-X, D -6120-X (manufactured by Takemoto Yushi Co., Ltd.), Solsperse 20000 (manufactured by Nippon Lubrizol Co., Ltd.), NAROACTY CL-95, HN-100 (manufactured by Sanyo Chemical Industries, Ltd.) and the like.

  Specific examples of the cationic surfactant include phthalocyanine derivatives (trade name: EFKA-745, manufactured by Morishita Sangyo Co., Ltd.), organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), (meth) acrylic acid ( Co) polymer polyflow no. 75, no. 90, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), W001 (manufactured by Yusho Co., Ltd.) and the like.

  Specific examples of the anionic surfactant include W004, W005, W017 (manufactured by Yusho Co., Ltd.), sanded BL (manufactured by Sanyo Chemical Industries, Ltd.), and the like.

Examples of the silicone surfactant include “Toray Silicone DC3PA”, “Toray Silicone SH7PA”, “Toray Silicone DC11PA”, “Tore Silicone SH21PA”, “Tore Silicone SH28PA”, “Toray Silicone” manufactured by Toray Dow Corning Co., Ltd. “Silicone SH29PA”, “Toresilicone SH30PA”, “Toresilicone SH8400”, “TSF-4440”, “TSF-4300”, “TSF-4445”, “TSF-4460”, “TSF” manufactured by Momentive Performance Materials, Inc. -4552 "," KP341 "," KF6001 "," KF6002 "manufactured by Shin-Etsu Silicone Co., Ltd.," BYK307 "," BYK323 "," BYK330 "manufactured by Big Chemie.
Only one type of surfactant may be used, or two or more types may be combined.
The addition amount of the surfactant is preferably 0.001% by mass to 2.0% by mass, and more preferably 0.005% by mass to 1.0% by mass with respect to the total mass of the aqueous composition.

(Hard coat layer / Laminated film)
The hard coat layer of the present invention is obtained by curing the above-described aqueous composition. The hard coat layer is formed by applying an aqueous composition on a support or the like and drying it.

  The thickness of the hard coat layer can be controlled by adjusting the coating amount of the aqueous composition. From the viewpoint of the hardness of the obtained hard coat layer, the average film thickness is preferably 2 μm or more. The average film thickness of the hard coat layer is preferably 2 μm or more, more preferably 3 μm or more, and further preferably 4 μm or more. The average film thickness of the hard coat layer is preferably 12 μm or less, more preferably 10 μm or less, and further preferably 8 μm or less. The thickness of the hard coat layer is more preferably constant within the above range. If the thickness is less than 2 μm, sufficient hardness may not be exhibited and the function as a hard coat layer may not be obtained. May end up.

  The refractive index of the hard coat layer can be in the range of 1.54 to 1.64, for example. By making the refractive index of a hard-coat layer into the said range, it can use suitably also for a touchscreen etc.

  The laminated film of the present invention preferably includes a laminate in which at least two hard coat layers are laminated. When one of the two hard coat layers is a first hard coat layer and the other is a second hard coat layer, the first hard coat layer includes inorganic particles having an average aspect ratio of 30 to 5000, The second hard coat layer includes inorganic particles having an average aspect ratio of 1 to 10. Here, the first hard coat layer is a hard coat layer formed by curing the above-described aqueous composition.

  The second hard coat layer is laminated on the first hard coat layer. The second hard coat layer is formed by applying and curing an aqueous composition containing inorganic particles having an average aspect ratio of 1 to 10 and a polymerizable monomer on the first hard coat layer. In addition, although other layers may be laminated | stacked between a 1st hard-coat layer and a 2nd hard-coat layer, it is preferable to laminate | stack adjacent.

  The average aspect ratio of the inorganic particles contained in the second hard coat layer is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 6, and the inorganic particles are substantially Particularly preferred is a spherical shape. Thus, the haze value can be lowered by laminating the second hard coat layer containing inorganic particles having a small average aspect ratio on the first hard coat layer.

  The average particle size of the inorganic particles contained in the second hard coat layer is preferably 50 nm or less, more preferably 40 nm or less, and further preferably 30 nm or less. By setting the average particle size of the inorganic particles contained in the second hard coat layer within the above range, the haze value of the laminated film can be more effectively lowered.

In the present invention, the difference between the content of the inorganic particles contained in the first hard coat layer and the content of the inorganic particles contained in the second hard coat layer is preferably within a certain range. Specifically, the difference in the content of the inorganic particles contained in the first hard coat layer and the second hard coat layer is 10% or less as an absolute value, not a ratio of each content, and 5% or less. Preferably there is.
The content ratio of the inorganic particles having an average aspect ratio of 30 to 5000 contained in the first hard coat layer is 25 to 65% by mass, preferably 30 to 60% by mass, and 30 to 40% by mass. It is more preferable. The content of the inorganic particles having an average aspect ratio of 1 to 10 contained in the second hard coat layer is 20 to 70% by mass, preferably 30 to 60% by mass, and 30 to 40% by mass. More preferably. Here, the content ratio of the inorganic particles indicates the ratio of the mass of the inorganic particles to the total mass of each hard coat layer.

  The difference in refractive index between the first hard coat layer and the second hard coat layer is preferably 0.1 or less, and more preferably 0.08 or less. Such a reduction in refractive index difference can be achieved by setting the difference in the content of the inorganic particles contained in the first hard coat layer and the second hard coat layer within the above range. In the present invention, by laminating two hard coat layers having a small difference in refractive index, the haze value of the laminated film in which the first hard coat layer and the second hard coat layer are laminated can be lowered. Thereby, a laminated film with low haze and high hardness can be obtained.

  The haze value of the laminated film in which the second hard coat layer is laminated on the first hard coat layer is preferably 1% or less, and more preferably 0.8% or less. In the present invention, a low-haze laminated film can be obtained by providing the second hard coat layer on the first hard coat layer.

  The total average film thickness of the first hard coat layer and the second hard coat layer is preferably 2 μm or more. The total average film thickness of the two hard coat layers is preferably 2 μm or more, more preferably 3 μm or more, and further preferably 4 μm or more. The total average film thickness of the two hard coat layers is preferably 12 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less. By setting the total of the average film thicknesses of the two hard coat layers within the above range, the haze value can be suppressed more effectively. Moreover, it can suppress that a laminated | multilayer film deform | transforms by making the sum total of the average film thickness of two hard-coat layers into the said range.

  It is preferable that the laminated film including the laminated body obtained by laminating the two hard coat layers as described above further has a support. The support is provided on one surface side of the first hard coat layer and on the side opposite to the surface on which the second hard coat layer is laminated. That is, in a laminated film having a support, each layer is configured in the order of support → first hard coat layer → second hard coat layer. In the present invention, a laminate obtained by laminating two hard coat layers is referred to as a laminate, and a film comprising this laminate or a film including this laminate is referred to as a laminate film.

  As the support on which the hard coat layer is laminated, a polymer compound formed into a film shape by a melt film forming method or a solution film forming method can be used. The polymer compound used for the support is not particularly limited, but polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polyarylates, polyether sulfone, polycarbonate Polyether ketone, polysulfone, polyphenylene sulfide, polyester-based liquid crystal polymer, triacetyl cellulose, cellulose derivative, polypropylene, polyamides, polyimide, polycycloolefins, and the like are preferable. Among these, PET, PEN, triacetyl cellulose, and cellulose derivatives are more preferable, and PET and PEN are particularly preferable.

  These supports are preferably biaxially stretched. Biaxial stretching refers to stretching in both directions by regarding the width direction and the longitudinal direction of the film as uniaxial. Thus, the biaxially stretched polyester film has very good mechanical strength because the molecular orientation in the biaxial direction is sufficiently controlled. The draw ratio is not particularly limited, but the draw ratio in one direction is preferably 1.5 to 7 times, more preferably 2 to 5 times. In particular, a polyester film that has been biaxially stretched at a stretching ratio of 2 to 5 times per uniaxial direction has a very excellent mechanical strength because the molecular orientation is controlled more efficiently and effectively. Suitable as a film.

  The support may have a surface subjected to corona treatment or glow treatment. By these treatments, the surface of the support is hydrophilized, and the wettability of the aqueous composition can be improved, so that the adhesion with the hard coat layer or the adhesion layer can be further increased.

  Furthermore, in this invention, it is preferable that the easily bonding layer is provided between the support body and the 1st hard-coat layer. The easy-adhesion layer is appropriately provided on the support in order to improve the adhesion between the support and the hard coat layer and to increase the adhesion with the hard coat layer. The easy-adhesion layer is usually formed by applying a coating liquid comprising a binder, a curing agent, and a surfactant to the surface of the support on which the hard coat layer is provided. Organic or inorganic fine particles may be appropriately added to the easy adhesion layer. Although not particularly limited, for example, metal oxides can be mentioned. Specifically, tin oxide, zirconium oxide, zinc oxide, titanium oxide, cerium oxide, niobium oxide and the like are preferable, and these are used alone or in combination of two or more. May be. Examples of commercially available products include ET-500W and other ET series, FT-2000 and other FT series, SN-100P and other SN series, FS-10D and other FS series (manufactured by Ishihara Sangyo Co., Ltd.).

  The binder used for the easy-adhesion layer is not particularly limited, but is preferably at least one of polyester, polyurethane, acrylic resin, and styrene-butadiene copolymer from the viewpoint of adhesiveness. In addition, a binder having water solubility or water dispersibility is particularly preferable from the viewpoint that the load on the environment is small. Examples of commercially available products include Carbodilite V-02-L2 and other Carbodilite series (Nisshinbo Co., Ltd.) Takelac WS-5100 and Takerak WS Series (Mitsui Chemicals).

  The thickness of the easy-adhesion layer can be appropriately adjusted by adjusting the coating amount. The thickness of the easy adhesion layer is more preferably constant in the range of 0.01 to 5 μm. If the thickness is less than 0.01 μm, the adhesiveness may be insufficient. If it is larger than 5 μm, it may be difficult to form an adhesive having a uniform thickness, and the amount of solution used may increase. The drying time takes too long and the cost increases. A more preferable thickness range is 0.02 to 3 μm. Only one layer may be sufficient as an easily bonding layer, and the aspect which piled up this may be sufficient. When a plurality of easy-adhesion layers are stacked, the total thickness of all the easy-adhesion layers is regarded as the thickness.

  The laminated film of the present invention has high transparency, and the transmittance of light having a wavelength of 340 nm among incident light can be in the range of 70% to 100%. Thereby, the laminated | multilayer film of this invention can be applied to various uses.

(Production method)
The hard coat layer is formed by applying the aqueous composition of the present invention to the surface of a support such as a polyester film. Specifically, the hard coat layer (first hard coat layer) is obtained by applying an aqueous composition containing inorganic particles having an aspect ratio of 30 to 5000 and a polymerizable monomer on a support and curing. be able to. In addition, the ratio for which an inorganic particle accounts with respect to the total solid in an aqueous composition is 25-65 mass% here.

  The laminated film is formed by providing a step of forming a second hard coat layer after the step of forming the first hard coat layer as described above. The step of forming the second hard coat layer is an aqueous composition containing inorganic particles having an average aspect ratio of 1 to 10 and a polymerizable monomer, and the ratio of the inorganic particles to the total solid content is 25 to 25%. Applying a 65% by weight aqueous composition on the first hardcoat layer. Thus, by forming the second hard coat layer on the first hard coat layer, the haze value of the entire laminated film can be kept low.

  The pH of the aqueous composition forming the first hard coat layer and the second hard coat layer is preferably adjusted in advance. For example, before the aqueous composition is applied, it is preferable to add an acidic solution to the aqueous composition and adjust the pH to a desired range. The acidic solution preferably has a pH of 2 to 6, and the aqueous composition is preferably adjusted to have a pH of 2 to 7, preferably 2 to 6.

Although the application | coating process of an aqueous composition may be provided in the middle of the extending process of a polyester film, it is preferable to be provided after an extending process. A known applicator can be used as appropriate for application of the aqueous composition. For example, a spin coater, a roll coater, a bar coater, a curtain coater, etc. can be mentioned.
A step of drying the coating solution is provided after the coating step. In the drying step, it is preferable to perform heat drying. In heat drying, heat treatment is preferably performed so that the temperature of the coating film is 120 ° C. or higher, the temperature of the coating film is more preferably 140 ° C. or higher, and further preferably 160 ° C. or higher. The temperature of the coating film is preferably 300 ° C. or lower, more preferably 280 ° C. or lower, and further preferably 260 ° C. or lower. By setting the heat treatment temperature within the above range, the coating film can be sufficiently cured, and deformation of the hard coat layer can be prevented. The heating time may be 10 seconds to 1 hour, and preferably 10 seconds to 5 minutes. In the present invention, in the heating step, it is sufficient to heat at a heating temperature of about 120 ° C. to 300 ° C., and the heating time is as short as about 10 seconds to 1 hour. For this reason, manufacturing efficiency can be improved and the cost concerning manufacture can be suppressed.

  The laminated film obtained after the drying step may then be wound into a roll or cut into a sheet. In addition, a heat treatment process may be provided in the drying process after an application | coating process, and may be provided in a heat treatment process, after winding up in roll shape.

  On the hard coat layer, another constituent layer may be further laminated to form a display device such as a touch panel. As a method for laminating other constituent layers, a conventionally known method can be appropriately selected.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

Example 1
An adhesive solution was prepared with the following composition. This adhesive solution was designated as an adhesive solution sample A.

[Adhesive solution sample A]
-Tin oxide dispersion 8.0 parts by weight (FS-10D, solid content concentration 20%, manufactured by Ishihara Sangyo Co., Ltd.)
-Takelac WS-5100 2.8 parts by weight (solid content concentration 30%, manufactured by Mitsui Chemicals, Inc.)
Carbodilite V-02-L2 4.2 parts by weight (solid content concentration 40%, manufactured by Nisshinbo Co., Ltd.)
・ Surfactant 0.2 part by weight (10% aqueous solution of Narrow Acty CL-95, manufactured by Sanyo Chemical Industries, Ltd.)
・ Surfactant 0.2 parts by weight (10% aqueous solution of Sandet BL, manufactured by Sanyo Chemical Industries)
・ 84.6 parts by weight of water

  One side of a PET film (Cosmo Shine A4300 125 μm, Toyobo) was subjected to corona discharge treatment. The adhesive solution sample A was applied to the surface subjected to the corona discharge treatment and dried at 120 ° C. for 2 minutes to form an adhesive layer having a thickness of 0.1 μm.

  A coating solution for forming a hard coat layer was prepared with the following composition. This coating solution was designated as coating solution sample A.

[Coating liquid sample A]
・ Tetraethoxysilane 50 parts by weight (KBE-04, manufactured by Shin-Etsu Chemical Co., Ltd.)
・ 50 parts by weight of 3-glycidoxypropyltriethoxysilane (KBE-403, manufactured by Shin-Etsu Chemical Co., Ltd.)
-Aqueous acetic acid solution (acetic acid concentration = 1%) 100 parts by weight-Curing agent 1 part by weight (Aluminum Chelate A (W), manufactured by Kawaken Fine Chemical Co., Ltd.)
Alumina sol 857 parts by weight (Fibrous boehmite sol F-1000, average major axis 1400 nm, average minor axis 4 nm,
(5% solid content, pH = 3.3, manufactured by Kawaken Fine Chemical Co., Ltd.)
-Surfactant 1 part by weight (10% aqueous solution of Narrow Acty CL-95, manufactured by Sanyo Chemical Industries, Ltd.)
・ 1800 parts by weight of water

The coating liquid sample A was prepared by the following method. First, 3-glycidoxypropyltrimethoxysilane was added to the acetic acid aqueous solution while vigorously stirring the acetic acid aqueous solution, and then the stirring was continued for 30 minutes. Next, tetramethoxysilane as tetraalkoxysilane was added to the acetic acid aqueous solution with vigorous stirring, and then the stirring was continued for 1 hour. Next, alumina sol was added to the alkoxysilane aqueous solution, and then stirring was continued for 30 minutes. Next, the curing agent was added and stirring was continued for 1 hour. Next, water was sequentially added so that the surfactant and the solid content would be 7% to prepare a coating solution sample A.
This coating solution sample A was applied onto the adhesive layer by a bar coating method, heated at 150 ° C. for 2 minutes and dried to form a hard coating layer having a thickness of 4.0 μm, and a laminated film was obtained.

The following (1) and (2) were evaluated about the coating liquid sample A and the obtained laminated film. These results are shown in Table 1.

(1) Presence / absence and degree of cracking of hard coat layer A baking treatment was performed at 150 ° C. for 1 hour, the hard coat layer was visually observed, and evaluated according to the following criteria. The more cracks there are and the more they are generated, the worse the light transmission, durability and appearance.
A: No cracks are observed B: Cracks are locally observed, but can be used depending on the application C: Levels where cracks are recognized over the entire surface and cannot be used as a product

(2) Pencil hardness Bake treatment at 150 ° C. for 1 hour, using a reciprocating wear tester, Tribogear (registered trademark) TYPE: 30S (manufactured by Shinto Kagaku Co., Ltd.), based on JIS K5600-5-4, The pencil hardness of the hard coat layer was measured at a moving speed of 0.5 mm / sec and a load of 750 g. The pencil hardness of the hard coat layer varies depending on the application, but when used on the outermost surface, it can be said that the function as the hard coat layer is satisfactory if it is “4H” or higher.

(Examples 2-6 and Comparative Examples 1-4)
An adhesive layer was formed in the same manner as in Example 1, and a coating solution sample prepared so as to have a blending ratio shown in Table 1 was applied in the same manner as in Example 1 to prepare a sample. The results of evaluation (1) and (2) are shown in Table 1.
The inorganic particles used here are
Aspect ratio 350: fibrous boehmite sol F-1000, average major axis 1400 nm, average minor axis 4 nm, solid content concentration 5%, pH = 3.3, aspect ratio 750 manufactured by Kawaken Fine Chemicals Co., Ltd .: fibrous boehmite sol F- 3000, average major axis 3000 nm, average minor axis 4 nm, solid content concentration 5%, pH = 3.0, aspect ratio 1: aluminum sol A2, manufactured by Kawaken Fine Chemicals Co., Ltd., average particle size 10-20 nm, solid content concentration 10%, pH = 3.8, Kawaken Fine Chemical Co., Ltd. aspect ratio 20: AKP-G015, average major axis 100 nm, average minor axis 5 nm, solid content concentration 5%, manufactured by Sumitomo Chemical Co., Ltd.

In Examples 1 to 6, the aspect ratio of the inorganic particles is within the range of 30 to 5000, and the solid content concentration of the inorganic particles contained in the aqueous composition forming the inorganic particles is 25% by mass or more. For this reason, in Examples 1-6, high pencil hardness is obtained without a crack, and it turns out that a hard-coat layer is high hardness.
On the other hand, in Comparative Example 1, the solid content concentration of the inorganic particles in the aqueous composition was less than 25% by mass. In this case, the aqueous composition gelled, and a hard coat layer having a preferable hardness was not obtained. . Moreover, in Comparative Examples 2-4, since the aspect-ratio is less than 30, it turns out that the hardness of a hard-coat layer is small.

(Examples 7-11 and Comparative Examples 5-7)
Furthermore, in Examples 7 to 11 and Comparative Examples 5 to 7, laminated films including a first hard coat layer and a second hard coat layer were produced.

  An adhesive layer was formed in the same manner as in Example 1, and a coating solution sample prepared so as to have a blending ratio shown in Table 2 as the first hard coat layer was applied in the same manner as in Example 1. Furthermore, as a second hard coat layer, a coating solution sample prepared so as to have a blending ratio shown in Table 2 was applied onto the first hard coat layer by a bar coat method, and dried by heating at 150 ° C. for 2 minutes. Then, a second hard coat layer having a thickness of 1.0 μm was formed to obtain a laminated film.

The inorganic particles used here are
Aspect ratio 350: fibrous boehmite sol F-1000, average major axis 1400 nm, average minor axis 4 nm, solid content concentration 5%, pH = 3.3, aspect ratio 750 manufactured by Kawaken Fine Chemicals Co., Ltd .: fibrous boehmite sol F- 3000, average major axis 3000 nm, average minor axis 4 nm, solid content concentration 5%, pH = 3.0, manufactured by Kawaken Fine Chemical Co., Ltd., aspect ratio 10: alumina sol-200, average major axis 100 nm, average minor axis 10 nm, solid content concentration 11%, pH = 4.8, manufactured by Nissan Chemical Industries, Ltd., aspect ratio 1: aluminum sol-A2, average particle size 10-20 nm, solid content concentration 10%, pH = 3.8, manufactured by Kawaken Fine Chemicals Co., Ltd. It is.

  Evaluation of said (1) and (2) and following (3) was implemented about the obtained laminated | multilayer film. These results are shown in Table 2.

(3) Haze The haze value was measured using a haze meter NDH5000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The haze value was measured based on JIS K7136.

In Examples 7-11, the aspect-ratio of the inorganic particle contained in a 1st hard-coat layer exists in the range of 30-5000, and the content rate of an inorganic particle is 25-65 mass%. Moreover, the aspect-ratio of the inorganic particle contained in a 2nd hard-coat layer is 1-10, and the content rate of an inorganic particle is 20-70 mass%. Further, the difference between the content of the inorganic particles in the first hard coat layer and the content of the inorganic particles in the second hard coat layer is 10% or less. For this reason, in Examples 7-11, it turns out that the haze value is restrained low. In particular, in Examples 7, 8, 10 and 11, the haze value is kept low.
On the other hand, Comparative Example 5 has a high haze value because the aspect ratio of the inorganic particles contained in the second hard coat layer is outside the range of 1 to 10. In Comparative Examples 6 and 7, the difference between the content of the inorganic particles in the first hard coat layer and the content of the inorganic particles in the second hard coat layer exceeds 10%. For this reason, the haze value tends to increase.

  According to the present invention, a hard coat layer having high hardness and excellent scratch resistance and impact resistance can be obtained. In addition, according to the present invention, since the hard coat layer can be formed from the aqueous composition, the load on the environment can be reduced, and the heating temperature at the time of film formation can be set low, Manufacture of a hard-coat layer can be made easy and manufacturing aptitude can be improved. The hard coat layer of the present invention can be suitably used for a display device such as a touch panel, and has high industrial applicability.

Claims (18)

An aqueous composition comprising inorganic particles and a polymerizable monomer,
The average aspect ratio of the inorganic particles is 30 to 5000,
A ratio of the inorganic particles to 25 to 65% by mass with respect to the total solid content in the aqueous composition is 25 to 65% by mass.   The aqueous composition according to claim 1, wherein the inorganic particles have an average aspect ratio of 300 to 800.   The ratio which the said inorganic particle accounts with respect to the total solid in the said aqueous composition is 30-60 mass%, The aqueous composition of Claim 1 or 2 characterized by the above-mentioned.   The aqueous composition according to claim 1, wherein the polymerizable monomer is an alkoxysilane.   The aqueous composition according to claim 4, wherein the alkoxysilane is a mixture of tetraalkoxysilane and alkyltrialkoxysilane.   The aqueous composition according to any one of claims 1 to 5, further comprising a curing accelerator.   The aqueous composition according to claim 6, wherein the curing accelerator is an aluminum chelate complex.   A hard coat layer formed by curing the aqueous composition according to claim 1. An inorganic having an average aspect ratio of 1 to 10 on the first hard coat layer formed by curing the aqueous composition according to any one of claims 1 to 7 and the first hard coat layer. Including a laminate in which a second hard coat layer containing particles is laminated,
The difference in the content of the inorganic particles contained in the first hard coat layer and the second hard coat layer is 10% or less.   The laminated film according to claim 9, wherein the average particle diameter of the inorganic particles contained in the second hard coat layer is 50 nm or less.   The laminated film according to claim 9 or 10, wherein a haze value is 1% or less.   Furthermore, it has a support body, and the said support body is provided in the one surface side of the said 1st hard-coat layer, and the opposite side to the surface where the said 2nd hard-coat layer was laminated | stacked. The laminated film according to any one of claims 9 to 11, wherein:   The laminated film according to claim 12, wherein an easy adhesion layer is further provided between the support and the first hard coat layer.   14. The laminated film according to claim 9, wherein the total of the average film thicknesses of the first hard coat layer and the second hard coat layer is 2 μm or more. An aqueous composition comprising inorganic particles having an average aspect ratio of 30 to 5,000 and a polymerizable monomer, wherein the proportion of the inorganic particles in the total solid content is 25 to 65% by mass on the support. And a step of forming a first hard coat layer,
The step of forming the first hard coat layer includes a step of heating at 120 to 300 ° C.   In the said process to heat, it heats at 120-300 degreeC for 10 second-1 hour, The manufacturing method of the laminated | multilayer film of Claim 15 characterized by the above-mentioned. After the step of forming the first hard coat layer, further comprising the step of forming a second hard coat layer,
The step of forming the second hard coat layer includes a step of applying an aqueous composition containing inorganic particles having an average aspect ratio of 1 to 10 and a polymerizable monomer on the first hard coat layer. The method for producing a laminated film according to claim 15 or 16.   The laminated film manufactured by the manufacturing method of any one of Claims 15-17.