WO2018185590A1

WO2018185590A1 - Hydrophilic hard coat laminate and method for manufacturing same

Info

Publication number: WO2018185590A1
Application number: PCT/IB2018/051931
Authority: WO
Inventors: Naota SUGIYAMA
Original assignee: 3M Innovative Properties Company
Priority date: 2017-04-05
Filing date: 2018-03-22
Publication date: 2018-10-11
Also published as: JP2018180099A

Abstract

A hydrophilic hard coat laminate with superior hydrophilicity and scratch resistance, and a method for manufacturing said laminate is provide. The hydrophilic hard coat laminate has an initial water contact angle of no more than approximately 20 degrees, and includes a base material and a hydrophilic hard coat layer, where the hydrophilic hard coat layer contains a hydrophilic binder and at least approximately 60 wt% of inorganic nanoparticles based on an entire weight of the hydrophilic hard coat layer, and the inorganic nanoparticles are dispersed in the hydrophilic binder.

Description

HYDROPHILIC HARD COAT LAMINATE AND METHOD FOR MANUFACTURING SAME

Cross Reference To Related Application

This application claims the benefit of Japanese Patent Application No. 2017-075514, filed April 5, 2017, the disclosure of which is incorporated by reference herein in its entirety.

Technical Field

The present disclosure relates to a hydrophilic hard coat laminate with superior hydrophilicity and scratch resistance, and a method for manufacturing said laminate.

Background

Coating agents having scratch resisting capabilities and films provided with a layer of said coating agent are used to protect windows on buildings, vehicles, optical displays, and the like.

Hydrophilic coating agents, films, and the like having a layer of said coating agent are also used to impart capabilities such as self-cleaning properties and anti-fogging properties.

PCT Patent Application Publication WO 2007/505359 discloses a durable optical film that includes a polymerized optical film structure having a micro structured surface and a plurality of surface- modified colloidal nanoparticles made from silica, zirconia, or a mixture thereof.

A molding, made from an anti-fogging resin sheet the surface of which is coated with a mixture of a polyhydric alcohol type nonionic surfactant and a polyethylene glycol type nonionic surfactant, is disclosed in patent application publication JP 2008-095116A, where the polyethylene glycol type nonionic surfactant is a polyoxypropylene polyoxyethylene block copolymer.

Summary of the Invention

Problem to be Solved by the Invention:

A hard coat agent to which an anti-fogging agent, such as a surfactant, has been added can impart temporary anti-fogging properties (hydrophilicity) in conjunction with bleeding of the surfactant. However, a layer made from such a hard coat agent not only has inferior scratch resistance but does not readily impart permanent anti-fogging properties. While an anti-fogging coating agent containing a hydrophilic resin can impart permanent anti-fogging properties, because the hydrophilic resin itself is a flexible resin said resin has problems in that both scratch resistance and hardness thereof are inferior.

Means for Solving the Problem :

The present disclosure provides a hydrophilic hard coat laminate with superior hydrophilicity and scratch resistance, and a method for manufacturing said laminate.

An embodiment of the present disclosure provides a hydrophilic hard coat laminate having an initial water contact angle of no more than approximately 20 degrees, and including a base material and a hydrophilic hard coat layer, where the hydrophilic hard coat layer contains a hydrophilic binder and at least approximately 60 wt% of inorganic nanoparticles based on an entire weight of the hydrophilic hard coat layer, and the inorganic nanoparticles are dispersed in the hydrophilic binder.

Another embodiment of the present disclosure provides a method for manufacturing the aforementioned hydrophilic hard coat laminate that includes: a step for forming an unhardened hydrophilic hard coat layer by randomly applying and then drying a hydrophilic hard coat agent containing an organic solvent having water-dispersible inorganic nanoparticles, a hydrophilic binder, water, and an organic solvent compatible with water, on a base material provided with a primer layer; and a step for hardening the unhardened hydrophilic hard coat layer.

Brief Description of the Drawings

FIG. 1 is a schematic view illustrating a hydrophilic hard coat laminate according to the present disclosure.

Detailed Description

The hydrophilic hard coat laminate in a first embodiment has an initial water contact angle of no more than approximately 20 degrees, is provided with a base material and a hydrophilic hard coat layer, where the hydrophilic hard coat layer contains a hydrophilic binder and at least approximately 60 wt% of inorganic nanoparticles based on an entire weight of the hydrophilic hard coat layer, and the inorganic nanoparticles are dispersed in the hydrophilic binder. The hydrophilic hard coat laminate can achieve a hard coat laminate with superior hydrophilicity, scratch resistance, and the like, because the hard coat layer not only contains the hydrophilic binder but a high degree of the inorganic nanoparticles that impart hydrophilicity, scratch resistance, and the like. Dispersion indicates that there is no aggregation. For example, if the inorganic nanoparticles are dispersed in a transparent hydrophilic binder, an initial haze value of the hydrophilic hard coat layer can be kept to no more than approximately 20%.

The hydrophilic hard coat laminate in the first embodiment can use, as the hydrophilic binder, at least one type selected from (meth)acrylic resins having at least one selected from resins having polyethylene glycol and a hydroxyl group, as well as, amphoteric ions, ethylene oxide, and propylene oxide. Because the hard coat layer contains a high degree of inorganic nanoparticles, said layer can enhance hardness, and the like, even if a flexible hydrophilic binder is used.

The hydrophilic hard coat laminate in the first embodiment can use, as the hydrophilic binder, at least one type selected from polyethylene glycol di(meth)acrylate and polypropylene glycol

di(meth)acrylate. These resins not only exhibit hydrophilicity, but also have superior scratch resistance, hardness, and the like.

The hydrophilic hard coat laminate in the first embodiment can use, as the inorganic

nanoparticles, at least one type of particle selected from particles made of silica, alumina, zinc oxide, zirconium oxide, tin-doped indium oxide, and antimony-doped tin oxide. Because these particles not only have excellent scratch resistance and hardness, but also have a relatively large number of hydrophilic locations, such as hydroxyl groups, and the like, on the surfaces thereof, the capabilities of the hard coat layer, in terms of hydrophilicity, scratch resistance, and the like, can be enhanced. Note that the hydrophilic hard coat laminate in the first embodiment can be produced using unmodified water- dispersible inorganic nanoparticles. Unmodified indicates that the end groups of the inorganic nanoparticle surfaces have not been modified by functional groups. Water-dispersible indicates a state where the inorganic nanoparticles do not aggregate in water. Producing the laminate using water- dispersible inorganic nanoparticles enables the realization of a hydrophilic hard coat laminate where an initial water contact angle is no more than approximately 20 degrees. The hydrophilic hard coat laminate may contain, based on the entire weight of the hydrophilic hard coat laminate, no more than

approximately 10 wt% of surface modified inorganic nanoparticles, preferably no more than

approximately 5 wt% thereof, and more preferably no more than approximately 1 wt% thereof, while it is most preferable that the laminate not contain any surface modified inorganic nanoparticles.

The hydrophilic hard coat layer in the hydrophilic hard coat laminate in the first embodiment may also contain a silane coupling agent. Because the inorganic nanoparticles and the hydrophilic binder can be bound together when the silane coupling agent is added to the hard coat layer, it becomes possible to prevent the inorganic nanoparticles from dropping out of the hard coat layer. In cases where an inorganic base material, such as glass, or the like, is used, the use of the silane coupling agent is useful in enhancing interlayer adhesion between the base material and the hard coat layer.

A ratio of an eluting hydrophilicity imparting component to water in the hydrophilic hard coat layer in the hydrophilic hard coat laminate in the first embodiment can be held to no more than 1.0 wt% with respect to the entire weight of the hydrophilic hard coat layer. When the ratio of the hydrophilicity imparting component of a surfactant, and the like, that can have an adverse effect on scratch resistance is within this range in the hydrophilic hard coat layer, scratch resistance can be enhanced.

The hydrophilic hard coat laminate in the first embodiment can have a hydrophilic hard coat layer thickness of no more than approximately 20 μπι.

The hydrophilic hard coat layer in the hydrophilic hard coat laminate in the first embodiment has a Δ haze value in the range of, for example, approximately -0.20% to approximately 0.20%. Here, the Δ haze value is a value after 10 cycles of a steel wool abrasion test using #0000 steel wool and a 350 g weight.

With conventional methods of manufacturing, it is difficult to add high amounts of unmodified water-dispersible inorganic nanoparticles to hard coat agents containing hydrophilic binders, and it is also difficult to apply said hard coat agents to base materials at a predetermined film thickness. Through the use of the method of manufacturing according to the present disclosure, which is described later, a hydrophilic hard coat layer that satisfies the aforementioned thickness and water contact angle can be formed. The hydrophilic hard coat laminate in the first embodiment can include a primer layer between the base material and the hydrophilic hard coat layer. Applying the primer layer allows an interlayer adhesion between the base material and the hydrophilic hard coat layer to be enhanced.

The method for manufacturing the hydrophilic hard coat laminate in the first embodiment includes: a step for forming an unhardened hydrophilic hard coat layer by randomly applying and then drying a hydrophilic hard coat agent containing an organic solvent having water-dispersible inorganic nanoparticles, a hydrophilic binder, water, and an organic solvent compatible with water, on a base material provided with a primer layer; and a step for hardening the unhardened hydrophilic hard coat layer.

In the method for manufacturing the hydrophilic hard coat laminate in the first embodiment, the hydrophilic hard coat agent contains water and at least one type of methanol, ethanol, isopropanol, and l-methoxy-2-propanol, and can contain at least approximately 30 wt% of water, based on the entire weight of the hydrophilic hard coat agent. Using water and an organic solvent compatible with water (especially, an organic solvent in which at least one type of methanol, ethanol, isopropanol, and 1- methoxy-2-propanol is mixed) in combination, allows the unmodified inorganic nanoparticles to be dispersed to a high degree in the hard coat agent containing the hydrophilic binder. The solubility parameter (SP) value of the organic solvent compatible with water is, for example, at least approximately 9.3, at least approximately 10.2, or less than 23.4. The SP value is the Hildebrand solubility parameter that is further described, for example, at https://en.wikipedia.org/wiki/Hildebrand_solubility_parameter.

A detailed description of the present invention is given below for the purpose of illustrating representative embodiments, but these embodiments should not be construed as limiting the present invention.

In the present disclosure, "(meth)acrylic" means acrylic or methacrylic, while "(meth)acrylate" means acrylate or methacrylate.

In the present disclosure, "hydrophilic" means having a lower water contact angle compared to the base material, or a capacity to exhibit water dispersibility or water solubility.

In the present disclosure, "dispersed" means not aggregated, while "water dispersibility" means a state where there the inorganic nanoparticles do not aggregate in water. For example, if the inorganic nanoparticles are dispersed in a transparent hydrophilic binder, an initial haze value of the hydrophilic hard coat layer can be kept to no more than approximately 20%.

In the present disclosure, "unmodified" means that the end groups of the inorganic nanoparticle surfaces have not been modified by functional groups.

A hydrophilic hard coat laminate 100 according to an embodiment of the present disclosure has an initial water contact angle of no more than approximately 20 degrees, and, as illustrated in FIG. 1, is provided with a base material 101 and a hydrophilic hard coat layer 104, where the hydrophilic hard coat layer 104 contains a hydrophilic binder 103 and at least approximately 60 wt% of inorganic

nanoparticles 102 based on an entire weight of the hydrophilic hard coat layer 104, and the inorganic nanoparticles 102 are dispersed in the hydrophilic binder 103.

Base Material

Examples of materials that can be used as the base material of the present disclosure include, but are not limited to, polycarbonates, poly(meth)acrylates (for example, poly methyl methacrylate

(PMMA)), polyolefins (for example, polyethylene (PE), polypropylene (PP)), polyurethanes, polyesters (for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN)), polyamides, polyimides, phenol resins, cellulose diacetates, cellulose triacetates, polystyrenes, styrene acrylonitrile copolymers, acrylonitrile butadiene styrene copolymers (ABS), epoxies, polyacetates, polyvinyl chlorides, glass, and the like. A film like base material, a plate like base material, a film like or plate like laminated base material, and the like, can be used as the base material. The base material may be transparent or may be colored and transparent. When used in the present specification "transparent" indicates that a total light transmittance in the visible region of the electromagnetic spectrum of at least 90%, and "colored and transparent" means a transparency that allows objects to be visible through a colored material, and a total light transmittance in such a case may be 90% or less.

When the base material is film like, thickness thereof can be in, but is not limited to, the range of at least approximately 5 μπι and less than approximately 500 μπι. When the base material is plate like, the thickness thereof can be at least approximately 0.5 mm and up to no more than approximately 10 mm, no more than approximately 5 mm, or no more than approximately 3 mm.

Hydrophilic Binder

Any binder that is water dispersible or water soluble can be used as the hydrophilic binder of the present disclosure, and examples include, but are not limited to, polyethylene glycols, poly-N- vinylpyrrolidones, polyvinyl acetates, poly(meth)acrylates (especially, (meth)acrylic resins having at least one selected from amphoteric ions, ethylene oxides, and propylene oxides), polyurethanes, resins having hydroxyl groups, and the like. The hydrophilic binder can improve scratch resistance of a hydrophilic hard coat layer containing the binder and/or adhesiveness with respect to a base material. In consideration of these capabilities, it is preferable to use, of these, at least one type selected from polyethylene glycol, a resin having a hydroxyl group, and (meth)acrylic resins having at least one of amphoteric ions, ethylene oxide, and propylene oxide. Polyvinyl alcohols, hydroxyl group-containing (meth)acrylic resins obtained from curable (meth)acrylic monomers or oligomers, hydroxyl group- containing polyester resins, and the like, can be used as the resins having a hydroxyl group. Note that when the silane coupling agent to be described below is a silane coupling agent that is hydrophilic and has a vinyl group or a (meth)acrylic group, such a silane coupling agent can be regarded as one type of hydrophilic binder.

When considering capabilities, such as hydrophilicity and scratch resistance, agents that are (meth)acrylic resins having at least one selected from ethylene oxide and propylene oxide are preferable. Such (meth)acrylic resins can be obtained by polymerizing hydrophilic monomers, such as polyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, polyethylene glycol tri(meth)acrylate, polypropylene glycol (meth)acrylate, polypropylene glycol di(meth)acrylate, polypropylene glycol tri(meth)acrylate, and the like. One type of these hydrophilic monomers may be used alone, or two or more types thereof may be used in combination. Such polyethylene glycol (meth)acrylates and polypropylene glycol (meth)acrylates can use various monomers with different ethylene and propylene chain lengths, and hydrophilicity can be controlled by chain length (n). For example, a binder with a chain length of at least one, and preferably with a chain length at least five, at least seven, or at least 10 can be used as the binder having hydrophilicity.

As long as the aforementioned (meth)acrylic resin is hydrophilic, one type or two or more types of a known curable type monofunctional monomer, or polyfunctional monomer or oligomer having, or not having, hydrophilicity may be used in combination with - out of the aforementioned hydrophilic monomers - polyethylene glycol di(meth)acrylate, polyethylene glycol tri(meth)acrylate, polypropylene glycol di(meth)acrylate, and polypropylene glycol tri(meth)acrylate, which are polyfunctional monomers.

A monofunctional monomer is a monomer having one ethylenic double bond. Examples of monomers that can be used as the monofunctional monomer include, but are not limited to, for example, 2-hydroxyethyl acrylate (HEA), 2-hydroxypropyl acrylate (HP A), 2-hydroxyethyl methacrylate (HEMA), styrene monomers, ethyl acrylate, butyl acrylate, and the like.

Curable type monomers having two or more reactive functional group are, for example, polyfunctional (meth)acrylate monomers, polyfunctional (meth)acrylic urethanes, and oligomers of these.

A polyfunctional (meth)acrylate type monomer is an organic compound having at least two (meth)acryloyloxy groups in each molecule. Examples of polyfunctional (meth)acrylate type monomers and oligomers that can be used include, but are not limited to, tricyclodecane dimethylol diacrylate, polypropylene glycol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethyipropane PO-modified triacrylate, glycerin PO adduct triacrylate, ε-caprolactone-modified tris (acroxyethyl) isocyanurate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, dendrimer acrylate, oligomers of these, and the like.

A polyfunctional (meth)acrylic urethane type monomer is an organic compound having at least two (meth)acryloyloxy groups in each molecule. Examples of polyfunctional (meth)acrylic urethane type monomers and oligomers that can be used include, but are not limited to, phenyl glycidyl ether acrylate hexamethylene diisocyanate urethane prepolymers, pentaerythritol triacrylate toluene diisocyanate urethane prepolymers, dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane

prepolymers, oligomers of these, and the like.

When hydrophilic polyfunctional monomers, non-hydrophilic polyfunctional monomers or oligomers, hydrophilic monofunctional monomers, and non-hydrophilic monofunctional monomers are used in combination, appropriate mixtures thereof can be used in consideration of hydrophilicity and scratch resistance.

Monomer polymerization can be performed through thermal polymerization and photo polymerization, but is not limited thereto. A thermal polymerization initiator is used in the case of thermal polymerization. Examples of what can be used as the thermal polymerization initiator include, but are not limited to, hydrophilic polymerization initiators, such as peroxides, such as potassium peroxodisulfide, ammonium peroxodisulfide, and the like, and azo compounds, such as VA-044, V-50, V-501, VA-057 (manufactured by Wako Pure Chemical Industries, Ltd.), and the like. Radical initiators, and the like, having polyethylene oxide chains can also be used. Ν,Ν,Ν',Ν'-tetramethylethylenediamine, β-dimethylaminopropionitrile, or the like, which are tertiary amine compounds, can be used as catalysts.

Photo polymerization can use, for example, an electron beam, ultraviolet rays, and the like. While is it not necessary to use a photo polymerization initiator when an electron beam is used, a photo polymerization initiator is used in the case of photo polymerization using ultraviolet rays. Examples of water soluble or hydrophilic photo polymerization initiators that can be used as the photo polymerization initiator include, but are not limited to, IRGACURE 2959, DAROCUR 1173, DAROCUR 1116, IRGACURE 184 (manufactured by BASF), QUANTACURE ABQ, BT, QTX (manufactured by Shell Chemical, Inc., and the like.

The hydrophilic binder can be used in the ranges of at least approximately 9 wt% or at least approximately 14 wt% and up to no more than approximately 39 wt%, no more than approximately 29 wt%, or no more than approximately 24 wt%, based on the entire weight (dry coating amount) of the hydrophilic hard coat layer.

Inorganic Nanoparticles

Examples of particles that can be used as the inorganic nanoparticles according to the present disclosure include, but are not limited to, at least one type of particle selected from particles made from silica (SiO, S1O2), alumina (AI2O3), zinc oxide (ZnO), zirconium oxide (ZrC ), tin-doped indium oxide (ITO), and antimony-doped tin oxide (ATO). Among these, silica, alumina, and zirconium oxide are preferred, with silica being particularly preferred. Because water dispersible silica nanoparticles have silanol groups on the surfaces thereof, such nanoparticles can enhance the hydrophilicity of the hard coat layer more than other particles can. Examples of particles that can be used as the inorganic nanoparticles include NALCO 2327 (manufactured by Nalco, Inc.) as silica particles; BIRAL AL-A7 (manufactured by Taki Chemical Co., Ltd.) as alumina particles; NANOBYK 3820 (manufactured by BYK, Inc.) as zinc oxide particles; BIRAL Zr-20 (manufactured by Taki Chemical Co., Ltd.) as zirconium oxide particles; PI-3 (manufactured by Mitsubishi Material Electronic Chemical Co., Ltd.) as tin-doped indium oxide particles; and 549541 (manufactured by Sigma-Aldrich, Co., Ltd.) as antimony -doped tin oxide particles. In consideration of hydrophilicity and scratch resistance, the inorganic nanoparticles according to the present disclosure are preferably particles that are unmodified and can be dispersed in water in an un-aggregated state, and particles that can be used as these nanoparticles include, but are not limited to, particles that disperse in water due to the electrostatic repulsion of particle surfaces alone, based on pH adjustment. Here, unmodified means that the end groups of the inorganic nanoparticle surfaces have not been modified by functional groups, and includes, for example, applying a treatment for bonding (covalent bonding, ionic bonding, or bonding through physical adsorption) a surface treating agent to the inorganic nanoparticle surfaces to make the inorganic nanoparticles readily dispersible in water and in the hard coat agent. When particles where the surfaces of the inorganic nanoparticles are exposed (in an unmodified state) without having been treated with a surface treating agent, such as a polymer, and the like, are used as the inorganic nanoparticles according to the present disclosure, the scratch resistance, hardness, and hydrophilicity of the inorganic nanoparticles themselves can be expressed through the hard coat layer to which the particles have been added.

The inorganic nanoparticles can be used in the ranges of at least approximately 60 wt%, at least approximately 70 wt%, or at least approximately 75 wt%, while examples of upper limit ranges in which the particles can be used include, but are not limited to, no more than approximately 90 wt% or no more than approximately 85 wt%. Because the inorganic nanoparticles are added to a high degree in the hard coat layer, said particles can enhance the scratch resistance and the hydrophilicity of the hard coat layer surface.

The average particle diameter of the inorganic nanoparticles can be measured by a Transmission Electron Microscope (TEM), or the like, using techniques in general use in the present technical field. To measure the average particle diameter of the inorganic nanoparticles, a sol sample for TEM images can be prepared by dropping a sol sample on a 400 mesh copper TEM lattice having an ultra-thin carbon substrate on an upper surface of a mesh lace carbon (available from Ted Pella, Inc. (Redding, CA)). A portion of the droplets can be removed by causing said droplets to make contact with filter paper, as well as, a side part or a bottom part of the lattice. The remaining sol solvent can be removed by heating or by leaving the particles to sit at room temperature. Therefore, the particles can be left on an ultra-thin carbon base material, and can thus be imaged with minimum interference from said base material. Next, TEM images can be recorded in many positions across the entire surface of the lattice. Enough images are recorded to enable particle diameter measurements of 500 to 1000 particles. Next, the average particle size of the inorganic nanoparticles can be calculated based on the particle diameter measured value in each of the samples. The TEM images can be obtained using a high-resolution transmission electron microscope (available from Hitachi Technologies under the commercial name "Hitachi H- 9000") operating (using an LaB6 source) at 300 KV. The images can be recorded using a camera (available, for example, from Gatan, Inc. (Pleasanton, CA) under the commercial name "GATAN ULTRASCAN CCD:" Model No. 895, 2k x 2k chip). The images can be captured magnified either 50,000 times or 100,000 times. In some samples, images can be captured magnified 300,000 times. The average particle diameter of the inorganic nanoparticles can be in the ranges of at least approximately 1 nm or at least approximately 2 nm, and no more than approximately 500 nm or no more than approximately 400 nm. The inorganic nanoparticles may be made up of a group of small particles and a group of large particles, in which case, the average particle diameter of the group of small particles can be in the ranges of at least approximately 2 nm, at least approximately 3 nm or at least

approximately 5 nm, and no more than approximately 200 nm, no more than approximately 150 nm, no more than approximately 120 nm, or no more than approximately 100 nm. The average particle diameter of the group of the large particles can be in the ranges of at least approximately 60 nm, at least approximately 65 nm, at least approximately 70 nm, or at least approximately 75 nm, and no more than approximately 400 nm, no more than approximately 350 nm, no more than approximately 300 nm, or no more than approximately 200 nm.

In consideration of the fact that the hydrophilic hard coat layer will be filled to a high degree with the inorganic nanoparticles, it is preferable to use a mixture of inorganic nanoparticles having a particle diameter distribution that includes at least two different types of inorganic nanoparticles. The particle diameter distribution of the inorganic nanoparticles may exhibit bimodality or multimodality, where peaks are the average particle diameter of the group of small particles and the average particle diameter of the group of large particles. In several embodiments, a ratio between an average particle diameter of inorganic nanoparticles having an average particle diameter in the range of approximately 2 nm to approximately 200 nm and an average particle diameter of inorganic nanoparticles having an average particle diameter in the range of approximately 60 nm to approximately 400 nm is in the range of 2: 1 to 200: 1, while, in several embodiments, the ratio is in the range of 2.5: 1 to 100: 1, or 2.5: 1 to 25: 1. Examples of combinations of preferred average particle diameters include 5 nm / 190 nm, 5 nm / 75 nm, 20 nm / 190 nm, 5 nm / 20 nm, 20 nm / 75 nm, 75 nm / 190 nm, or 5 nm / 20 nm / 190 nm. By using a mixture of inorganic nanoparticles with different sizes, the hard coat layer can be filled with a large amount of inorganic nanoparticles, and thus, the hardness, scratch resistance, and hydrophilicity capabilities of the hard coat layer can be increased.

For example, transparency (haze, etc.), scratch resistance, hardness, hydrophilicity, and the like, can be changed by selecting the type, volume, size, and ratio of the inorganic nanoparticles.

A mass ratio (%) between the group of small particles and the group of large particles can be selected based on the used particle diameter or on a combination of the used particle diameters. It is possible to select preferable mass ratios based on the used particle diameter or combinations of used particle diameters using software that can be obtained under the commercial name "CALVOLD2." For example, selection can be made based on simulations between mass ratios and fill rates of the group of small particles and the group of large particles with respect to a combination (group of small particles/group of large particles) of particle diameters (also see, "Verification of a Model for Estimating the Void Fraction in a Three-Component Randomly Packed Bed," M. Suzuki and T. Oshima: Powder Technol., 43, 147-153 (1985). Hydrophilic Hard Coat Layer

The hydrophilic hard coat layer according to the present disclosure can be applied to one or both sides of a base material. Examples of hydrophilic hard coat layer thickness ranges that can be used include, but are not limited to, at least approximately 0.1 μιη, at least approximately 0.5 μιη, or at least approximately 1 μιη, and up to no more than approximately 20 μιη, no more than approximately 15 μιη, or no more than approximately 10 μιη.

To the degree that doing so does not cause defects in capabilities, such as hydrophilicity, scratch resistance, and the like, known additives, such as silane coupling agents, ultraviolet light absorbers, leveling agents, anti-static agents, dyes, and the like, can be added to the hydrophilic hard coat layer as needed. Here, examples of preferably used silane coupling agents include, but are not limited to, epoxy- modified alkoxysilanes, such as amino-modified alkoxysilanes, glycidyl-modified alkoxysilanes, and the like, and hydrophilic silane coupling agents, such as polyether-modified alkoxysilanes, zwitterionic alkoxysilanes, and the like. Because the inorganic nanoparticles and the hydrophilic binder can be bound together when the silane coupling agent is added to the hard coat layer, it becomes possible to prevent the inorganic nanoparticles from dropping out of the hard coat layer. In cases where an inorganic base material, such as glass, or the like, is used, the use of the silane coupling agent is useful in enhancing interlayer adhesion between the base material and the hard coat layer. For example, when a silane coupling agent having a vinyl group and a (meth)acrylic group is used, said agent can be used as the hydrophilic binder. Therefore, the silane coupling agent can be used in the ranges of at least approximately 0.1 wt% or at least approximately 1 wt%, and up to no more than approximately 39 wt%, no more than approximately 29 wt%, or no more than approximately 24 wt%, based on the entire weight (dry coating amount) of the hydrophilic hard coat layer.

For example, a hydrophilicity imparting component eluting with respect to a surfactant, such as water, and the like, may bleed onto the hard coat layer surface, and thus lower the transparency and scratch resistance of the hard coat layer. Hydrophilicity imparting components include, for example, anti -fogging property imparting components. The hydrophilic hard coat layer according to the present disclosure may contain a hydrophilicity imparting component that elutes with respect to water in the ranges of no more than approximately 1.0 wt%, no more than approximately 0.5 wt%, or no more than approximately 0.01 wt%, based on the entire weight of the hard coat layer. It is more preferable that the layer not contain a hydrophilicity imparting component. For example, the hydrophilic hard coat layer according to the present disclosure can exhibit adequate hydrophilicity even when said layer does not contain a hydrophilicity imparting component that elutes with respect to water.

Hydrophilic Hard Coat Laminate

Because the hydrophilic hard coat layer according to the present disclosure can be filled to an adequately high degree with unmodified inorganic nanoparticles even if said particles are not coarsened, in such cases, the layer will have not only hydrophilicity and scratch resistance, but excellent transparency as well. Accordingly, when the hard coat layer is applied to one surface of a transparent base material, such as a general optical film, and the like, for example, COSMO SHINE A4100

(manufactured by Toyobo Co., Ltd.) to a thickness of 1.5 μπι, an initial haze value of the obtained laminate can be reduced to no more than approximately 5%, no more than approximately 3%, or no more than approximately 1%. A steel wool abrasion resistance test using #0000 steel wool and a 350 g weight can make a Δ haze value (base value after 10 cycles - initial haze value) in this hydrophilic hard coat laminate approximately - 0.20% to approximately 0.20%, approximately - 0.15% to approximately 0.15%, or approximately - 0.10% to approximately 0.10%. The hydrophilicity of the hydrophilic hard coat layer can be expressed in terms of, for example, a water contact angle, and the initial water contact angle in the hydrophilic hard coat layer is no more than approximately 20 degrees, no more than approximately 17 degrees, or no more than approximately 15 degrees.

To increase adhesion between the hydrophilic hard coat layer and the base material, the base material surface of the hydrophilic hard coat laminate according to the present disclosure may be surface treated, and a primer layer may be applied onto said base material surface.

Examples of surface treatments include surface treatments well-known in the present technical field, such as plasma treatments, corona discharge treatments, flame treatments, electron beam irradiation, roughening, ozone treatments, chemical oxidation treatments using chromic acid or sulfuric acid, and the like.

Examples of the primer layer material include (meth)acrylic resins ((meth)acrylic

homopolymers, copolymers of two or more (meth)acrylates, or copolymers of a (meth)acrylate and another polymerizable monomer), urethane resins (for example, two-liquid curable urethane resins composed of polyols and isocyanate curing agents), (meth)acrylic urethane copolymers (for example, acrylic urethane block copolymers), chlorinated polyolefins (for example, chlorinated polyethylenes, chlorinated polypropylenes), polyester resins, butyral resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate copolymers, , and the like, and copolymers and derivatives thereof (for example, chlorinated ethylene -propylene copolymers, chlorinated ethylene-vinyl acetate copolymers, (meth) acrylic-modified chlorinated polypropylenes, maleic anhydride-modified chlorinated polypropylenes, and urethane-modified chlorinated polypropylenes), and the like.

The primer layer can be formed by applying, drying, and, when necessary, heat curing or photo curing a primer solution - prepared by dissolving the aforementioned resins in solvent - on the base material using a method well-known in the present technical field, such as, for example, bar coating, deep coating, spin coating, capillary coating, spray coating, gravure coating, screen printing, and the like. The thickness of the primer layer can be in the ranges of at least approximately 0.1 μπι or at least approximately 0.5 μπι, and up to no more than approximately 20 μπι or no more than approximately 5 μπι. A base material provided with a primer layer can be used. Examples of base materials that can be used include LUMIRROR U32 (manufactured by Toray, Inc.), COSMO SHINE A4100 and A4300 (manufactured by Toyobo Co., Ltd.), and the like.

A colored layer, a decorative layer, a conductive layer, an adhesive layer, a pressure-sensitive adhesive layer, or the like, may be applied, for example, between the hydrophilic hard coat layer and the base material or on the base material surface on the opposite side of the hydrophilic hard coat layer of the hydrophilic hard coat laminate according to the present disclosure.

The hydrophilic hard coat laminate according to the present disclosure may be sheet material or roll body wound like roll.

Method for Manufacturing Hydrophilic Hard Coat Laminate

The hydrophilic hard coat laminate according to the present disclosure can be manufactured using, for example: a step for forming an unhardened hydrophilic hard coat layer by randomly applying and then drying a hydrophilic hard coat agent - containing an organic solvent having water-dispersible inorganic nanoparticles, a hydrophilic binder, water, and an organic solvent compatible with water - on a base material provided with a primer layer; and a step for hardening the unhardened hydrophilic hard coat layer. Here, "compatible with water" means that the water and the organic solvent are mixed together uniformly without separating from one another. The SP value of the organic solvent compatible with water is, for example, at least approximately 9.3, at least approximately 10.2, or less than 23.4.

The hydrophilic hard coat agent according to the present disclosure can be prepared by combining specific components. For example, the hydrophilic hard coat agent can be obtained by mixing a sol of water-dispersible inorganic nanoparticles and a reaction initiator with a hydrophilic binder (hydrophilic curable monomer) in a solvent, and then adding solvent as needed to adjust to a desired solids content. For example, a photo polymerization initiator or a thermal polymerization initiator well- known in the present technical field can be used as the reaction initiator.

For example, unmodified water-dispersible inorganic nanoparticles are dispersed in the sol by nothing more than the electrostatic repulsion between the particles. Therefore, it is difficult to disperse inorganic nanoparticles in a hydrophilic hard coat agent containing a hydrophilic binder, and the like. When a hard coat agent with insufficient dispersion is used, the inorganic nanoparticles aggregate such that particle diameter is too large, which thus reduces the performance of the obtained hard coat layer in terms of transparency, and the like. The ability to disperse unmodified water-dispersible inorganic nanoparticles in the hydrophilic hard coat agent when the hydrophilic hard coat agent is adjusted in the manufacturing method according to the present disclosure depends on the solvent selected. A mixed solvent of water and an organic solvent compatible with water can be used as the solvent. The amount of water that can be used in the mixed solvent is at least approximately 30 wt%, at least approximately 35 wt%, at least approximately 40 wt%, at least approximately 50 wt%, or at least approximately 60 wt%, based on the entire weight of the hydrophilic hard coat agent. At least one type out of methanol, ethanol, isopropanol, l-methoxy-2-propanol, and the like, can be used as the organic solvent compatible with water. It is preferable to use an organic solvent of l-methoxy-2-propanol mixed with at least one type out of methanol, ethanol, and isopropanol. The mass ratio between the water and the organic solvent compatible with water can be 30:70, 35:65, 40:60, 50:50, or 60:40. The mass ratio between the 1- methoxy-2-propanol and the at least one type out of methanol, ethanol, and isopropanol in the organic solvent compatible with water can be 95:5, 90: 10, 80:20, 70:30, 60:40, 50:50, or 40:60.

For example, bar coating, deep coating, spin coating, capillary coating, spray coating, gravure coating, screen printing, or the like, may be suitably used as the technique for applying the hydrophilic hard coat agent to the surface of the base material. The coated hydrophilic hard coat agent can be dried, and then, cured using a polymerizing method well-known in the present technical field, such as photo polymerization or thermal polymerization using ultraviolet rays or electron beams, as needed. The hydrophilic hard coat laminate according to the present disclosure can be obtained by forming the hydrophilic hard coat layer on the base material in this way.

Application

The hydrophilic hard coat laminate according to the present disclosure is useful for various products like, for example, optical displays (for example, Cathode Ray Tubes (CRTs), Light Emitting Diode (LED) displays), cards, camera lenses or bodies, fans, door knobs, faucet handles, mirrors, and consumer electronic goods such as vacuums and clothes washers, as well as, devices, such as portable information terminals (PDAs), mobile phones, Liquid Crystal Display (LCD) panels, touch screens, and detachable computer screens, and the like. The hydrophilic hard coat laminate according to the present disclosure can also be used in, for example, furniture, doors, windows, toilets and bathtubs, vehicle interior and exterior members, lenses (for eyeglasses or goggles), liquid transporting members, medical components, solar panels, or the like.

Examples

In the following examples, specific embodiments of the present disclosure are given by way of example, but the present invention should not be construed as being restricted thereto. All portions and percentages are by mass unless otherwise indicated.

Evaluation Method

The characteristics of the hydrophilic hard coat according to the present disclosure were evaluated in accordance with the following methods.

1. Optical Characteristics

The optical characteristics (haze and total light transmittance (TT)) of the hydrophilic hard coat laminate, and the like, were measured before and after the steel wool abrasion resistance test shown below using an NDH-5000W (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with both JIS K7136 (2000) and JIS K7361-1 (1997). 2. Steel Wool Abrasion Resistance Test

The scratch resistance of the hard coat layer, and the like, was evaluated based on surface changes after a steel wool abrasion resistance test. A 27 mm square of #0000 steel wool was used in a steel wool abrasion resistance test device (Rubbing Tester IMC-157C, manufactured by Imoto

Machinery Co., Ltd.) to polish the surface of the hard coat layer, and the like, 10 times (strokes) using a 350 g weight, 85 mm strokes, and a speed of 60 cycles per minute. After the sample was polished, the degree of scratching of the sample surface was confirmed both using the aforementioned optical measuring device, and visually. The confirmation using the optical measuring device evaluated total light transmittance, haze, and Δ haze (haze after abrasion test - initial haze). The visual confirmation evaluated the sample according to five stages, being "Absolutely no scratches: 0," "Several slight scratches observed only with reflected light: 1," "Several slight scratches: 2," "Several slight scratches and several deep scratches: 3," and "Many deep scratches easily observed with reflected light or transmitted light, or the coating has peeled off completely: 4."

3. Water Contact Angle

The water contact angle of the hard coat layer, and the like, was measured according to the Sessile Drop Method using a contact angle meter (available from Kyowa Interface Science Co., Ltd. under the commercial name "DROP MASTER FACE"). The water contact angle was measured based on an optical microscope image taken after 2 of water was dripped on the surface of the hard coat layer, and the like. The value of the water contact angle was calculated from an average of five measurements.

4. Adhesiveness Test

Adhesive performance was evaluated using the crosscut method in accordance with JIS K5600. Here, a 5 ^χ 5 grid with grid spacing of 1 mm, and CELLOPHANE TAPE CT-24 (manufactured by Nichiban Co., Ltd.) were used.

The raw materials, and the like, used in the present example are shown below in Table 1.

Table 1

SR9035 15 mol ethoxylated trimethylolpropane Arkema Group (U.S.) triacrylate

SAC Silane coupling agent prepared as described 3M Company (U.S.)

in Preparative Example 7 of U.S. Patent

Publication No. 2015/0203708 (Klun et al.).

The structure is CH₂=CH-(CO)0-(CH₂)₂- 0(CO)-NH-(CH₂)3-Si(OCH₃)3.

SILQUEST A- 174 Silane coupling agent: 3- Alfa Aesar (U.S.)

methacryloxypropyltrimethoxysilane

IRGACURE 2959 1- [4- (2-hydroxyethoxy) -phenyl] -2- BASF Japan, Inc.

hydroxy-2 -methyl- 1 -propane- 1 -one (Minato-ku, Tokyo, Japan)

PROSTAB 4-hydroxy-2,2,6,6-trimethyl piperidine- 1 -oxyl BASF Japan, Inc.

(Minato-ku, Tokyo, Japan)

MIPA 1 -methoxy-2-propanol Sigma Aldrich (U.S.)

IPA 2-propanol Sigma Aldrich (U.S.)

COSMO SHINE A4100 50 um thick PET film, one surface treated for Toyobo Co., Ltd. (Osaka, easy adhesion Japan)

COSMO SHINE A4300 50 um thick PET film, both surfaces treated Toyobo Co., Ltd. (Osaka, for easy adhesion Japan)

Preparation of Modified Silica Sol (Modified Sol 1)

A comparative example modified silica sol ("Modified Sol 1") was prepared as described below. 5.95 g of SILQUEST A-174 and 0.5 g of PROSTAB were added to a mixture of 400 g NALCO 2329 and 450 g of MIPA in a glass bottle, and the mixture was stirred for 10 minutes at room temperature. The bottle was sealed, and was then placed in an 80°C oven for 16 hours. The bottle was then cooled to room temperature. At 60°C, water was removed from the obtained solution using a rotary evaporator until the solid content of the solution reached close to 45 wt%. 200 g of MIPA was added to the obtained solution, and then, at 60°C, the rotary evaporator was used to remove the remaining water. The latter half steps were repeated twice to remove even more water from the solution. Finally, a total concentration of Si0₂ nanoparticles was adjusted to 45 wt% by adding MIPA, and thus an Si0₂ sol (hereinafter, Modified Sol 1) containing surface modified Si0₂ nanoparticles with an average particle diameter 75 nm was obtained.

Preparation of Modified Silica Sol (Modified Sol 2)

A comparative example modified silica sol ("Modified Sol 2") was prepared as described below. 25.25 g of SILQUEST A-174 and 0.5 g of PROSTAB were added to a mixture of 400 g NALCO 2327 and 450 g of MIPA in a glass bottle, and the mixture was stirred for 10 minutes at room temperature. The bottle was sealed, and was then placed in an 80°C oven for 16 hours. The bottle was then cooled to room temperature. At 60°C, water was removed from the obtained solution using a rotary evaporator until the solid content of the solution reached close to 45 wt%. 200 g of MIPA was added to the obtained solution, and then, at 60°C, the rotary evaporator was used to remove the remaining water. The latter half steps were repeated twice to remove even more water from the solution. Finally, a total concentration of S1O2 nanoparticles was adjusted to 45 wt% by adding MIPA, and thus an S1O2 sol (hereinafter, Modified Sol 2) containing surface modified S1O2 nanoparticles with an average particle diameter 20 nm was obtained.

Preparation of Hydrophilic Hard Coat Agent 1

3.09 g of NALCO 2329, 1.25 g of NALCO 2327, 0.49 g of EBECRYL 11, and 0.01 g of SAC were mixed. 0.06 g of IRGACURE 2959 was added to the mixture as a polymerization initiator. Next, 1.60 g of IPA, 2.40 g of MIPA, and 1.17 g of distilled water were added and adjusted until a solid content reached 20.48 wt%, and thus Hydrophilic Hard Coat Agent 1 was prepared.

Preparation of Hydrophilic Hard Coat Agent 2

3.29 g of NALCO 2329, 1.33 g of NALCO 2327, 0.39 g of EBECRYL 11, and 0.008 g of SAC were mixed. 0.06 g of IRGACURE 2959 was added to the mixture as a polymerization initiator. Next, 1.60 g of IPA, 2.40 g of MIPA, and 0.98 g of distilled water were added and adjusted until a solid content reached 20.48 wt%, and thus Hydrophilic Hard Coat Agent 2 was prepared.

Preparation of Hard Coat Agent A Containing Modified Sol

23.1 g of Modified Sol 1, 1.24 g of Modified Sol 2, 0.39 g of EBECRYL 11, and 0.008 g of SAC were mixed. 0.06 g of IRGACURE 2959 was added to the mixture as a polymerization initiator. Next, 1.60 g of IPA, and 4.44 g of MIPA distilled water were added and adjusted until a solid content reached 20.48 wt%, and thus Hard Coat Agent A was prepared.

Preparation of Hard Coat Agent B Containing Modified Sol

23.1 g of Modified Sol 1, 1.24 g of Modified Sol 2, 0.39 g of SR9035, and 0.008 g of SAC were mixed. 0.06 g of IRGACURE 2959 was added to the mixture as a polymerization initiator. Next, 1.60 g of IPA, and 4.44 g of MIPA were added and adjusted until a solid content reached 20.48 wt%, and thus Hard Coat Agent B was prepared.

Preparation of Hard Coat Agent C Containing Modified Sol

23.1 g of Modified Sol 1, 1.24 g of Modified Sol 2, and 0.4 g of EBECRYL 11 were mixed. 0.06 g of IRGACURE 2959 was added to the mixture as a polymerization initiator. Next, 1.60 g of IPA, and 4.44 g of MIPA were added and adjusted until a solid content reached 20.48 wt%, and thus Hard Coat Agent C was prepared.

Preparation of Hard Coat Agent D Containing Modified Sol

23.1 g of Modified Sol 1, 1.24 g of Modified Sol 2, and 0.4 g of EBECRYL 11 were mixed. 0.06 g of IRGACURE 2959 was added to the mixture as a polymerization initiator. Next, 1.60 g of IPA, and 4.44 g of MIPA were added and adjusted until a solid content reached 20.48 wt%, and thus Hard Coat Agent D was prepared.

The composition of each type of adjusted hard coat agent (HC) is shown in Table 2. Note that contained amounts are all in grams.

Table 2

Example 1 A hydrophilic hard coat agent HC-1 was applied to a surface treated for easy adhesion of a 50 μηι thick COSMO SHINE A4100 base material using a #8 mayer rod, and was then dried for five minutes at 60°C. Next, a base material to which a hydrophilic hard coat layer had been applied was passed twice through a UV irradiator (H-Bulb (DRS Model) by Fusion UV System, Inc.) under a nitrogen atmosphere to thus cure the hydrophilic hard coat layer. At this time, ultraviolet rays (UV-A) were irradiated onto the hydrophilic hard coat layer surface under the conditions of illuminance of 700 mW/cm² and total amount of light of 900 mJ/cm². In this way, a hydrophilic hard coat laminate having a 1.5 μιη thick hydrophilic hard coat layer was produced.

Example 2

Except that Hydrophilic Hard Coat Agent HC- 1 was replaced with Hydrophilic Hard Coat Agent HC-2, a hydrophilic hard coat laminate was produced in the same way as in Example 1.

Example 3

A hydrophilic hard coat agent HC-2 was applied to one side of a surface treated for easy adhesion of a 50 μιη thick COSMO SHINE A4300 base material using a #8 mayer rod, and was then dried for five minutes at 60°C. Next, a base material to which a hydrophilic hard coat layer had been applied was passed twice through a UV irradiator (H-Bulb (DRS Model) by Fusion UV System, Inc.) under a nitrogen atmosphere to thus cure the hydrophilic hard coat layer. At this time, ultraviolet rays (UV-A) were irradiated onto the hydrophilic hard coat layer surface under the conditions of illuminance of 700 mW/cm² and total amount of light of 900 mJ/cm². The thickness of the hydrophilic hard coat layer was 1.5 μιη. Next, Hydrophilic Hard Coat Agent HC-2 was applied to the side of the A4300 surface treated for easy adhesion on which a hydrophilic hard coat layer had not been formed using a #8 mayer rod, and was then dried for five minutes at 60°C. Next, a base material to which a hydrophilic hard coat layer had been applied was passed twice through a UV irradiator (H-Bulb (DRS Model) by Fusion UV System, Inc.) under a nitrogen atmosphere to thus cure the hydrophilic hard coat layer. At this time, ultraviolet rays (UV-A) were irradiated onto the hydrophilic hard coat layer surface under the conditions of illuminance of 700 mW/cm² and total amount of light of 900 mJ/cm². The thickness of the hydrophilic hard coat layer was 1.5 μιη. In this way, a hydrophilic hard coat laminate having a 1.5 μιη thick hydrophilic hard coat layers on both surfaces was produced.

Comparative Example 1

A 50 μιη thick COSMO SHINE A4100, which is a polyethylene terephthalate film, was used as Comparative Example 1.

Comparative Example 2

A 50 μπι thick COSMO SHINE A4300, which is a polyethylene terephthalate film, was used as Comparative Example 2.

Comparative Example 3

Except that Hydrophilic Hard Coat Agent HC-1 was replaced with Hydrophilic Hard Coat Agent HC-A, a hydrophilic hard coat laminate was produced in the same way as in Example 1.

Comparative Example 4

Except that Hydrophilic Hard Coat Agent HC-1 was replaced with Hydrophilic Hard Coat Agent HC-B, a hydrophilic hard coat laminate was produced in the same way as in Example 1.

Comparative Example 5

Except that Hydrophilic Hard Coat Agent HC-1 was replaced with Hydrophilic Hard Coat Agent HC-C, a hydrophilic hard coat laminate was produced in the same way as in Example 1.

Comparative Example 6

Except that Hydrophilic Hard Coat Agent HC- 1 was replaced with Hydrophilic Hard Coat Agent HC-D, a hydrophilic hard coat laminate was produced in the same way as in Example 1.

Examples 1 through 3 and Comparative Examples 1 through 6 were evaluated, and the results are shown in Table 3.

Table 3

Initial characteristics After steel wool abrasion test

Optical Adhesion Water (350 g, 10 times, 2.7 x 2.7 cm²,

characteristics contact #0000)

TT Haze angle (°) TT Haze AHaze Visual Water

(%) (%) (%) (%) (%) results contact

angle (°)

Example 1 90.96 0.51 25/25 11.6 90.75 0.65 0.14 1 17.8

Example 2 90.69 0.42 25/25 15.1 90.53 0.44 0.02 1 20.2

Example 3 92.69 0.33 25/25 13.8 92.65 0.36 0.03 1 24.7

Comparative 89.62 0.71 76.0 90.54 6.68 5.97 4 76.4

Example 1

Comparative 90.66 1.20 72.1 91.74 6.49 5.29 4 74.3

Example 2

Comparative 90.83 0.55 25/25 59.1 90.74 0.62 0.07 0 42.9

Example 3 Comparative 90.75 0.99 25/25 66.3 90.73 0.73 -0.26 0 46.4 Example 4

Comparative 90.74 0.55 25/25 60.8 90.75 0.58 0.03 0 45.7

Example 5

Comparative 90.63 0.57 25/25 64.7 90.66 0.60 0.03 0 41.0

Example 6

As can be seen from the results for Examples 1 through 3 and Comparative Examples 1 and 2, it was confirmed not only that the hydrophilic hard coat layer according to the present disclosure is superior in terms of transparency and adhesion, but that said layer improved hydrophilicity and scratch resistance significantly. As can be seen from the results for Examples 1 through 3 and Comparative Examples 3 through 6, it was confirmed that the hydrophilic hard coat layer according to the present disclosure is able to enhance hydrophilicity better than hard coat layers using modified and treated silica particles.

It is obvious to anyone skilled in the art that the aforementioned embodiments and examples can be modified in various ways without departing from the basic principle of the present invention. It is also obvious to anyone skilled in the art that a variety of improvements and modifications can be made to the present invention without departing from the spirit and scope of the present invention.

Reference Numerals:

100 Hydrophilic hard coat laminate

101 Base material

102 Inorganic nanoparticles

103 Hydrophilic binder

104 Hydrophilic hard coat layer

Claims

What is Claimed is:

1. A hydrophilic hard coat laminate, comprising:

a base material; and

a hydrophilic hard coat layer, wherein the hydrophilic hard coat laminate has an initial water contact angle of no more than approximately 20 degrees, and

the hydrophilic hard coat layer contains

a hydrophilic binder, and

at least 60 wt% of inorganic nanoparticles based on a total weight of the hydrophilic hard coat layer,

and the inorganic nanoparticles are dispersed in the hydrophilic binder.

2. The hydrophilic hard coat laminate according to claim 1, wherein the hydrophilic binder is at least one type selected from polyethylene glycol, resins having a hydroxyl group, and (meth)acrylic resins having at least one selected from amphoteric ions, ethylene oxide, and propylene oxide.

3. The hydrophilic hard coat laminate according to claim 1 or 2, wherein the hydrophilic binder contains at least one type selected from polyethylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate.

4. The hydrophilic hard coat laminate according to any one of claims 1 through 3, wherein the inorganic nanoparticles are at least one type selected from particles made from silica, alumina, zinc oxide, zirconium oxide, tin-doped indium oxide, and antimony-doped tin oxide.

5. The hydrophilic hard coat laminate according to any one of claims 1 through 4, wherein the hydrophilic hard coat layer also contains a silane coupling agent.

6. The hydrophilic hard coat laminate according to any one of claims 1 through 5, wherein a ratio of a hydrophilicity imparting component, that elutes with respect to water, in the hydrophilic hard coat layer is no more than 1.0 wt% with respect to an entire weight of said hydrophilic hard coat layer.

7. The hydrophilic hard coat laminate according to any one of claims 1 through 6, wherein a thickness of the hydrophilic hard coat layer is no more than 20 μιη.

8. The hydrophilic hard coat laminate according to any one of claims 1 through 7, wherein the hydrophilic hard coat layer has a Δ haze value in the range of - 0.20% to 0.20%, and

the Δ haze value is a value after 10 cycles of a steel wool abrasion resistance test using #0000 steel wool and a 350 gram weight.

9. The hydrophilic hard coat laminate according to any one of claims 1 through 8, further comprising:

a primer layer between the base material and the hydrophilic hard coat layer.

10. A method for manufacturing a hydrophilic hard coat laminate, which method is a method for manufacturing the hydrophilic hard coat laminate according to any one of claims 1 through 9, comprising:

a step of forming an unhardened hydrophilic hard coat layer by randomly applying and then drying a hydrophilic hard coat agent containing an organic solvent having water-dispersible inorganic nanoparticles, a hydrophilic binder, water, and an organic solvent compatible with water, on a base material provided with an arbitrary primer layer; and

a step of hardening the unhardened hydrophilic hard coat layer.

11. The method for manufacturing a hydrophilic hard coat laminate according to claim 10, wherein the hydrophilic hard coat agent contains water and at least one alcohol type selected from methanol, ethanol, isopropanol, and l-methoxy-2-propanol, and contains at least 30 wt% of said water, based on the entire weight of the hydrophilic hard coat agent.