HK1207104A1 - Anti-reflective hard coat and anti-reflective article - Google Patents

Abstract

An anti-reflective hard coat contains a nanoparticle mixture and a binder and has a dry-etched surface. The nanoparticles constitute from 40 to 95 mass% of an entire mass of the anti-reflective hard coat. From 10 to 50 mass% of the nanoparticles have an average particle size within a range of 2 to 200 nm. From 50 to 90 mass% of the nanoparticles have an average particle size within a range of 60 to 400 nm. A ratio of the average particle size of nanoparticles having an average particle size within the range of 60 to 400 nm to the average particle size of nanoparticles having an average particle size within a range of 2 to 200 nm is from 2:1 to 200:1. The particle size distribution of the nanoparticles is bimodal or multimodal.

Description

Antireflective hardcoat and antireflective article

Cross Reference to Related Applications

This patent application claims priority from japanese patent application JP 2012-170716, filed on 8/1/2012, the disclosure of which is incorporated by reference in its entirety.

Technical Field

The present disclosure relates to antireflective hardcoats and antireflective articles.

Background

Anti-reflective (AR) coatings are used to obtain sharp video images by avoiding the projection of internal light, etc., onto the display. Further, a hard coat treatment is sometimes performed for providing the display surface with scratch resistance against scratches caused by wiping with cloth or the like or contact with nails or the like.

Japanese unexamined patent application publication 2006-297680 describes "a low refractive index film in which a solid substrate is alternatively immersed in (a) a dispersion of fine particles containing an electrolyte at a concentration of 0.01 to 0.25 mol/liter and (B) an ionic polymer solution having a charge opposite to the surface charge of the fine particles, whereby a particulate laminate film is formed from the microparticles and the polymer alternatively laminated on the substrate, and the particulate laminate film has a pore structure that does not allow scattering of visible light. "

Japanese unexamined patent application publication 2002-079616 describes "a transparent coated substrate composed of a substrate and a transparent coating layer provided on a surface of the substrate, the transparent coating layer having (i) a matrix containing a siloxane component containing a fluorine-substituted alkyl group and (ii) an outer shell layer, wherein an inner member contains inorganic compound particles so as to be porous or hollow, and porous or hollow quality is maintained in the transparent coating layer. "

Japanese unexamined patent application publication H07-092305 describes "a low refractive index antireflection film in which (1) a portion composed of a mixture of air and organic ultrafine particles having a surface roughness formed by exposing the surface of the organic ultrafine particles having a refractive index of at most 1.45 is formed at the outermost layer of the antireflection film, (2) a portion composed of the organic ultrafine particles is formed inside the antireflection film extending from the outermost layer, in which the outermost layer of the organic ultrafine particles is crosslinked or fused by itself, and (3) the antireflection film has a refractive index gradually increasing from the outermost layer toward the bottom. "

The japanese translation of published PCT patent application 2012-514238 describes a composite formed by a process having the steps of "providing a matrix comprising a nanodispersed phase and forming an anisotropic surface with random nanostructures by etching the matrix using a plasma", wherein the composite is used as an article having nanostructures useful as an antireflective article.

Comprising SiO modified by a photocurable silane coupling agent₂Nanoparticle hardcoat materials are described in U.S. Pat. Nos. 5104929 and 7074463.

There is also a strong need to provide anti-smudge properties to display surfaces. Hardcoat materials having antifouling properties and having an easily washable surface obtained by curing a polymerizable composition comprising a fluorine compound having hexafluoropropylene oxide sites are described in U.S. patent 7718264 and U.S. patent application publication 2008/0124555.

Disclosure of Invention

It is an object of the present disclosure to provide an antireflective hardcoat and an antireflective article having excellent scratch resistance.

One embodiment of the present disclosure provides an antireflective hardcoat comprising a nanoparticle mixture and a binder, the antireflective hardcoat having a dry etched surface; the nanoparticles constitute 40 to 95 mass% of the entire mass of the hard coat layer; 10 to 50 mass% of the nanoparticles have an average particle size in the range of 2 to 200 nm; 50 to 90 mass% of the nanoparticles have an average particle size in the range of 60 to 400 nm; the ratio of the average particle size of the nanoparticles having an average particle size in the range of 60nm to 400nm to the average particle size of the nanoparticles having an average particle size in the range of 2nm to 200nm is in the range of 2:1 to 200: 1.

Another embodiment of the present disclosure provides an antireflective article comprising a substrate and a layer of antireflective hardcoat, wherein the substrate has a first surface and the layer of antireflective hardcoat is disposed on the first surface of the substrate.

The antireflective hardcoat of the present disclosure filled with high levels of nanoparticles exhibits both excellent scratch resistance and impact resistance, and exhibits high antireflective properties resulting from moth-eye structures formed on the dry etched surface.

The above description should not be taken as a disclosure of all embodiments of the invention or all advantages of the invention.

Drawings

Fig. 1 is a graph showing the results of a simulation between the mass ratio of the small particle group to the large particle group and the filling rate for several combinations of particle sizes (small particle group/large particle group).

Fig. 2 is a cross-sectional view of an antireflective article according to an embodiment of the disclosure.

Fig. 3 is a cross-sectional view of an antireflective article according to another embodiment of the disclosure.

Fig. 4 is a cross-sectional view of a display unit including an antireflective article of an embodiment of the disclosure.

Fig. 5 is a cross-sectional view of a display unit including an antireflective article according to another embodiment of the disclosure.

Fig. 6 is a cross-sectional view of a display unit including an antireflective article according to another embodiment of the disclosure.

Fig. 7 is a graph showing the transmittance measurement results of example 1 and comparative example 1.

Fig. 8 is a graph showing the transmittance measurement results of example 2 and comparative example 2.

Fig. 9 is a graph showing the transmittance measurement results of example 3 and comparative example 3.

Fig. 10 is a graph showing the transmittance measurement results of example 4 and comparative example 4.

Fig. 11 is a graph showing the transmittance measurement results of examples 5 to 8 and comparative examples 5 and 6.

Fig. 12 is a graph showing the transmittance measurement results of examples 9 and 10 and comparative examples 5 and 7.

Fig. 13 is a graph showing the transmittance measurement results of examples 11 and 12 and comparative examples 5 and 8.

Detailed Description

The present invention will be further described in detail below for the purpose of illustrating representative embodiments of the present invention, however, the present invention is not limited to these embodiments.

In the present disclosure, "(meth) acrylic" means "acrylic or methacrylic", and "(meth) acrylate" means "acrylate or methacrylate". Further, "antireflective hard coat layer" refers to a hard coat layer in which reflection of light in the visible light range is reduced or suppressed at least some areas of the hard coat layer surface. Further, "dry etched surface" refers to a surface that has been at least partially subjected to dry etching.

The antireflective hardcoat of one embodiment of the present disclosure comprises a nanoparticle mixture and a binder and has a dry etched surface.

Examples of representative binders contained in the antireflective hardcoat layer include resins obtained by polymerizing curable monomers and/or curable oligomers and resins obtained by polymerizing sol-gel glass. More specific examples include acrylic resins, polyurethane resins, epoxy resins, phenol resins, and polyvinyl alcohol resins. Further, the curable monomer or curable oligomer may be selected from curable monomers or curable oligomers known in the art, and a mixture of two or more curable monomers, a mixture of two or more curable oligomers, or a mixture of one or two or more curable monomers and one or two or more curable oligomers may be used. In several embodiments, examples of resins include dipentaerythritol pentaacrylate (e.g., Sartomer Company, Exton, PA, available under the product name "SR 399" from Sartomer Company, Exton, axton, PA), pentaerythritol triacrylate isophorone diisocyanate (IPDI) (e.g., Nippon kayaku co, ltd., Tokyo Japan under the product name "UX-5000"), urethane acrylates (e.g., Nippon Synthetic Chemical Industry co., ltd., Tokyo Japan under the product name "UV 1700B" and "UB 6300B"), trimethylhydroxy diisocyanate/hydroxyethyl acrylate (TMHDI/HEA, e.g., dazo polyester Company, available under the product name "ecrryl 58" from Tokyo cellulose Company, da ltd., Japan, ltd., Tokyo Japan)), polyethylene oxide (PEO) modified bis-a-diacrylate (e.g., a product name "R551" available from Nippon Kayaku co., ltd., Tokyo Japan), PEO modified bis-a-epoxyacrylate (e.g., a product name "3002M" available from kyo Chemical co., Osaka), a silane-based UV curable resin (e.g., a product name "SK 501M" available from Nagase mtex Corporation, Osaka, Japan), and 2-phenoxyethyl methacrylate (e.g., a product name "SR 340" available from sartome company, sartany, and a polymer mixture of these compounds. For example, when 2-phenoxyethyl methacrylate is used in the range of about 1.0 to 20 mass%, improvement in adhesion to polycarbonate is observed. When a bifunctional resin (e.g., PEO-modified bis-a-diacrylate "R551") and trimethylhydroxydiisocyanate/hydroxyethyl acrylate (TMHDI/HEA) (e.g., available under the product name "EBECRYL 4858" from celluloid-cyanotex corporation (Daicel-Cytec Company, ltd., Tokyo Japan) of Tokyo, Japan) were used, the hardcoat was observed to improve in hardness, impact resistance, and flexibility at the same time.

The amount of binder in the antireflective hardcoat layer is typically about 5 to 60 mass%, and in several embodiments about 10 to 40 mass% or about 15 to 30 mass% of the total mass of the antireflective hardcoat layer. According to the present disclosure, even if the amount of the binder is relatively small, the antireflective hard coating layer can be formed.

The antireflective hardcoat layer may also be cured with another curable monomer or curable oligomer, if necessary. Representative examples of curable monomers or curable oligomers include multifunctional (meth) acrylic monomers and multifunctional (meth) acrylic oligomers selected from the group consisting of: (a) compounds having two (meth) acrylic groups such as 1, 3-butanediol diacrylate, 1, 4-butanediol diacrylate, 1, 6-hexanediol monoacrylate, ethylene glycol diacrylate, alkoxylated aliphatic diacrylates, alkoxylated cyclohexanedimethanol diacrylates, alkoxylated hexanediol diacrylates, alkoxylated neopentyl glycol diacrylates, caprolactone-modified neopentyl glycol hydroxypivalate diacrylate, cyclohexanedimethanol diacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, ethoxylated (10) bisphenol-A-diacrylate, ethoxylated (3) bisphenol-A-diacrylate, ethylene glycol diacrylate, ethylene, Ethoxylated (30) bisphenol-A diacrylate, ethoxylated (4) bisphenol-A diacrylate, hydroxypivalaldehyde modified trimethylolpropane diacrylate, neopentyl glycol diacrylate, polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate, propoxylated neopentyl glycol diacrylate, tetraethylene glycol diacrylate, tricyclodecane dimethanol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, and the like; (b) compounds having three (meth) acrylic groups such as glycerol triacrylate, trimethylolpropane triacrylate, ethoxylated triacrylates (e.g., ethoxylated (3) trimethylolpropane triacrylate, ethoxylated (6) trimethylolpropane triacrylate, ethoxylated (9) trimethylolpropane triacrylate, ethoxylated (20) trimethylolpropane triacrylate, etc.), pentaerythritol triacrylate, propoxylated triacrylates (e.g., propoxylated (3) glyceryl triacrylate, propoxylated (5.5) glyceryl triacrylate, propoxylated (3) trimethylolpropane triacrylate, propoxylated (6) trimethylolpropane triacrylate, and the like), trimethylolpropane triacrylate, tris- (2-hydroxyethyl) isocyanurate triacrylate, and the like; (c) compounds having four (meth) acrylic groups such as ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, ethoxylated (4) pentaerythritol tetraacrylate, caprolactone-modified dipentaerythritol hexaacrylate, and the like; (d) oligomer (meth) acrylic compounds such as urethane acrylates, polyester acrylates, epoxy acrylates, and the like; polyacrylamide analogues of the above; and combinations thereof. Such compounds are commercially available, and at least several of these compounds are available from Sartomer Company (Sartomer Company), UCB chemicals of sammaca, georgia (ucbcchemicals Corporation, Smyrna, GA), Aldrich chemicals of Milwaukee, wisconsin, and the like. Examples of other useful (meth) acrylates include hydantoin moiety-containing poly (meth) acrylates such as those disclosed in U.S. patent 4262072.

Preferred curable monomers or curable oligomers contain at least three (meth) acrylic groups. Preferred commercially available curable monomers or curable oligomers include those available from Sartomer Company (Sartomer Company), such as trimethylolpropane triacrylate (TMPTA) (product name: "SR 351"), pentaerythritol tri/tetraacrylate (PETA) (product names: "SR 444" and "SR 295"), and dipentaerythritol pentaacrylate (product name: "SR 399"). In addition, mixtures of multifunctional (meth) acrylates and monofunctional (meth) acrylates may be used, such as a mixture of PETA and 2-phenoxyethyl acrylate (PEA).

The mixture of nanoparticles included in the antireflective hardcoat layer constitutes about 40 to 95 mass% of the total mass of the antireflective hardcoat layer, and in several embodiments, about 60 to 90 mass% or about 70 to 85 mass% of the total mass of the antireflective hardcoat layer. The nanoparticle mixture includes about 10 to 50 mass% of nanoparticles having an average particle size in a range of about 2 to 200nm (hereinafter referred to as a small particle group or a first nanoparticle group) and about 50 to 90 mass% of nanoparticles having an average particle size in a range of about 60 to 400nm (hereinafter referred to as a large particle group or a second nanoparticle group). For example, the nanoparticle mixture may be obtained by mixing a first nanoparticle group having an average particle size of about 2nm to 200nm and a second nanoparticle group having an average particle size of about 60nm to 400nm in a mass ratio of about 10:90 to 50: 50.

The average particle size of the nanoparticles can be measured using Transmission Electron Microscopy (TEM) using techniques commonly used in the art. In the measurement of the average particle size of the nanoparticles, a sol sample for TEM images can be prepared by dropping the sol sample into a 400-mesh copper TEM grid with an ultra-thin carbon substrate (from Ted Pella inc., Redding, CA) on the upper surface of the mesh lace-like carbon. Some of the liquid droplets may be removed by contacting the droplets with filter paper and the side or bottom portions of the mesh. The remaining sol solvent can be removed by heating or allowing the solution to remain at room temperature. This allows the particles to remain on the ultra-thin carbon substrate and be imaged with minimal interference from the substrate. Next, TEM images may be recorded at many locations across the entire grid. Enough images were recorded to allow measurement of particle sizes of 500 to 1000 particles. Next, the average particle size of the nanoparticles may be calculated based on the particle size measurements of each sample. The TEM image may be taken using a high resolution transmission electron microscope (using LaB)₆Source) (available under the product name "Hitachi H-9000" from Hitachi High technologies corporation) was obtained by operating at 300 KV. A camera (available under the product name "GATANULTRASCAN CCD" from Gatan, inc., great santon, CA) of pleisenton, california may be used, for example: model 895, 2k × 2k sheet) recorded the image. The image may be taken at a magnification of 50,000 to 100,000 times. Images may be taken at 300,000 times magnification for several samples.

The nanoparticles are typically inorganic particles. Examples of the inorganic particles include inorganic oxides such as aluminum oxide, zinc oxide, antimony oxide, silicon dioxide (SiO )₂) Zirconia, titania, ferrites, and the like, and mixtures thereof, or mixed oxides thereof; metal vanadates, metal tungstates, metal phosphates, metal nitrates, metal sulfates, metal carbides, and the like. Inorganic oxide sols can be used as the inorganic oxide nanoparticles. As the silica nanoparticles, for example, a silica sol obtained by using liquid glass (sodium silicate solution) as a raw material can be usedAnd (5) obtaining the product. Depending on the manufacturing conditions, the silica sol obtained from the liquid glass can have a very narrow particle size distribution; therefore, when the silica sol is used, a hard coating layer having desired characteristics can be obtained by more precisely controlling the filling rate of the nanoparticles in the hard coating layer.

The small particle groups have an average particle size in the range of about 2nm to 200 nm. The particle size is preferably from about 2nm to 150nm, from about 3nm to 120nm, or from about 5nm to 100 nm. The large particle group has an average particle size in the range of about 60nm to 400 nm. The particle size is preferably from about 65nm to 350nm, from about 70nm to 300nm, or from about 75nm to 200 nm.

The nanoparticle mixture comprises a particle size distribution of at least two different types of nanoparticles. The particle size distribution of the nanoparticle mixture may exhibit a bimodal or multimodal peak at the average particle size of the small particle group and the average particle size of the large particle group. In addition to the particle size distribution, the nanoparticles may be the same as or different from each other (e.g., compositionally surface modified or not) in several embodiments, the ratio of the average particle size of the nanoparticles having an average particle size in the range of about 2nm to 200nm to the average particle size of the nanoparticles having an average particle size in the range of about 60nm to 400nm is in the range of 2:1 to 200:1 and, in several embodiments, in the range of 2.5:1 to 100:1 or 2.5:1 to 25: 1. Examples of preferred average particle size combinations include combinations of 5nm/190nm, 5nm/75nm, 20nm/190nm, 5nm/20nm, 20nm/75nm, 75nm/190nm, and 5nm/20nm/190 nm. By using a mixture of nanoparticles of different sizes, the antireflective hardcoat can be filled with a large number of nanoparticles, thereby increasing the hardness of the antireflective hardcoat.

Further, the transmittance (haze, etc.) and hardness can be varied by selecting, for example, the type, amount, size, and ratio of nanoparticles. In several embodiments, antireflective hardcoats having both desired transmittance and hardness can be obtained.

The mass ratio (%) of the small particle group to the large particle group may be selected according to the particle size used or the combination of the particle sizes used. The preferred mass ratio can be selected by using software obtained under the product name "CALVOLD 2" according to the particle size used or the particle size combination used, and can be selected based on a simulation between the mass ratio and the filling ratio of the small-particle group and the large-particle group for the particle size combination (small-particle group/large-particle group), for example (see also "Verification of a Model for estimating the Void Fraction in a Three-Component Randomly filled base" (Verification of a Model for estimating the Void Fraction in a Three-Component Randomly filled base) ", m.suzuki and t.oshima: Powder technology (Powder technology.), 43, 147-. The simulation results are shown in fig. 1. According to the simulation, the mass ratio (small particle group: large particle group) for the combination of 5nm/190nm was about 45:55 to 13:87 or about 40:60 to 15: 85. The mass ratio for the combination of 5nm/75nm is preferably about 45:55 to 10:90 or about 35:65 to 15: 85. The mass ratio for the combination of 20nm/190nm is preferably about 45:55 to 10: 90. The mass ratio for the combination of 5nm/20nm is preferably about 50:50 to 20: 80. The mass ratio for the combination of 20nm/75nm is preferably about 50:50 to 22: 78. The mass ratio for the combination of 75nm/190nm is preferably about 50:50 to 27: 73.

In several embodiments, the use of preferred particle size combinations and nanoparticles makes it possible to increase the amount of nanoparticles that fill the antireflective hardcoat and adjust the transmittance and hardness of the resulting antireflective hardcoat.

The thickness of the hard coat layer is typically in the range of about 80nm to 30 μm (in several embodiments, about 200nm to 20 μm or about 1 μm to 10 μm), however, even when the thickness deviates from these ranges, the hard coat layer may sometimes be effectively used. The use of a mixture of nanoparticles of different sizes sometimes makes it possible to obtain an antireflective hardcoat with greater thickness and higher hardness.

If necessary, the surface of the nanoparticles may be modified using a surface treatment agent. The surface treatment agent typically has a first end bonded to the surface of the particle (by covalent, ionic, or strong physisorption) and a second end that imparts compatibility of the particle with the resin and/or reacts with the resin during curing. Examples of surface treatment agents include alcohols, amines, carboxylic acids, sulfonic acids, phosphonic acids, silanes, and titanates. The preferred type of surface treatment agent is determined in part by the chemistry of the nanoparticle surface. Silanes are preferred when silica or another siliceous filler is used as the nanoparticles. For metal oxides, silanes and carboxylic acids are preferred. The surface modification may be performed before, during or after mixing with the curable monomer or curable oligomer. When a silane is used, the reaction between the silane and the surface of the nanoparticles is preferably performed before mixing with the curable monomer or curable oligomer. The required amount of surface treatment agent is determined by several factors such as the particle size and type of the nanoparticles and the molecular weight and type of the surface treatment agent. It is generally preferred to deposit a layer of surface treatment agent onto the surface of the particles. The desired deposition procedure or reaction conditions are also determined by the surface treatment agent used. When silane is used, the surface treatment is preferably performed at high temperature under acidic or basic conditions for about 1 to 24 hours. In the case of surface treatment agents such as carboxylic acids, high temperatures or long periods of time are generally not necessary.

Representative examples of surface treatments include compounds such as isooctyltrimethoxysilane, polyalkylene oxide alkoxysilanes (e.g., obtained under the product designation "SILQUEST A1230" from Momentive Specialty Chemicals Inc., Columbus, OH), N- (3-triethoxysilylpropyl) methoxyethoxyethylethyl carbamate, 3- (methacryloyloxy) propyltrimethoxysilane (e.g., obtained under the product designation "SILQUEST A174" from Alfa Aesar, Ward Hill, MA, Wodel, Mass.), 3- (acryloyloxy) propyltrimethoxysilane, 3- (methacryloyloxy) propyltriethoxysilane, 3- (methacryloyloxy) propylmethyldimethoxysilane, 3- (acryloyloxy) propylmethyldimethoxysilane, 3- (methacryloyloxy) propyldimethylethoxysilane, vinyldimethylethoxysilane, phenyltrimethoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, octadecyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, vinylmethyldiacetoxysilane, vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri (t-butoxy) silane, vinyltri (isobutoxy) silane, vinyltriisopropenoxysilane, vinyltri- (2-methoxyethoxy) silane, styrylethyltrimethoxysilane, vinyldimethylethoxysilane, vinyltriethoxysilane, mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, acrylic acid, methacrylic acid, oleic acid, stearic acid, dodecanoic acid, 2- [2- (2-methoxyethoxy) ethoxy ] acetic acid (MEEAA), beta-carboxyethyl acrylate, 2- (2-methoxyethoxy) acetic acid, and methoxyphenylacetic acid and mixtures thereof.

The binder of the antireflective hardcoat layer may further contain known additives such as ultraviolet absorbers, antifouling agents, antifogging agents, leveling agents, ultraviolet reflecting agents, or antistatic agents.

In some embodiments, the uv absorber is included in the binder of the antireflective hardcoat. According to this embodiment, wavelength selectivity (absorption of ultraviolet rays and transmission of visible light) can be provided for the antireflective hard coating layer. The ultraviolet absorber may be mixed with the curable monomer or curable oligomer. Known agents may be used as ultraviolet light absorbers. For example, ultraviolet absorbers such as benzophenone absorbers (e.g., from BASF AG under the product name "Uvinul 3050"), benzotriazole absorbers (e.g., from BASF AG under the product name "Tinuvin 928"), triazine absorbers (e.g., from BASF AG under the product name "Tinuvin 1577"), salicylate absorbers, diphenylacrylate absorbers, and cyanoacrylate absorbers and Hindered Amine Light Stabilizers (HALS) (e.g., from BASF AG under the product name "Tinuvin 292") may be used. By using the known ultraviolet absorber and the hindered amine light stabilizer in combination, the ultraviolet absorption of the antireflective hardcoat layer can be further increased as compared with the use of the respective components alone.

The amount of the ultraviolet absorber added may be, for example, in the range of about 0.01 to 20 parts by mass (in several embodiments, about 0.1 to 15 parts by mass or about 0.2 to 10 parts by mass) relative to 100 parts by mass of the total of the nanoparticles, the curable monomer, and the curable oligomer. In some embodiments, an antireflective hardcoat comprising an ultraviolet absorber can achieve less than 3% ultraviolet transmission.

In some embodiments, the anti-fouling agent is included in the binder of the antireflective hardcoat. It was observed that the anti-soiling agent improved the washability of the anti-reflective hard coat surface (e.g., by avoiding the adhesion of fingerprints, oil-repellent, dust-repellent and/or soil-repellent function). Fluorinated (meth) acrylic compounds are useful as antifouling agents. Examples of the fluorinated (meth) acrylic compound include HFPO urethane acrylate or modified HFPO described in japanese unexamined patent application publication 2008-538195. The fluorinated (meth) acrylic compound may be contained in the binder of the antireflective hardcoat layer as an unreacted fluorinated (meth) acrylic compound, as a reaction product resulting from reaction with a curable monomer or curable oligomer, or as a combination thereof. Silicone polyether acrylates (available, for example, from avonik gold schmitt, EvonicGoldschmidt GmbH, Essen, Germany under the product name "TEGORAD 2250") can also be used as antifouling agents.

In the present disclosure, HFPO is referred to as F (CF (CF3) CF)₂O)_nCF(CF₃) A perfluoroether moiety represented by- (n is 2 to 15) and a compound containing such a perfluoroether moiety.

The antifouling agent is preferably a multifunctional fluorinated (meth) acrylic compound. The multifunctional fluorinated (meth) acrylic compound has a plurality of (meth) acrylic groups and thus can react with a curable monomer or curable oligomer as a crosslinking agent or non-covalently interact with functional groups contained in the binder at a plurality of sites. Therefore, the durability of the antifouling property can be increased. When a polyfunctional fluorinated (meth) acrylic compound is used as the stain resistant agent, the scratch resistance can also be increased by reducing the friction coefficient of the surface of the antireflective hardcoat layer. When a polyfunctional fluorinated (meth) acrylic compound having three or more (meth) acrylic groups is used, the durability of the antifouling property can be further increased.

Since the perfluoroether group provides excellent antifouling property to the antireflective hard coating layer, the polyfunctional fluorinated (meth) acrylic compound is preferably a perfluoroether compound having two or more (meth) acrylic groups.

For example, polyfunctional perfluoroether (meth) acrylates described in Japanese unexamined patent application publication No. 2008-538195 and Japanese unexamined patent application publication No. 2008-527090 are useful as perfluoroether compounds having two or more (meth) acrylic groups. Specific examples of such multifunctional perfluoroether (meth) acrylates include:

HFPO-C(O)N(H)CH(CH₂OC(O)CH＝CH₂)₂；

HFPO-C(O)N(H)C(CH₂CH₃)(CH₂OC(O)CH＝CH₂)₂；

HFPO-C(O)NHC(CH₂OC(O)CH＝CH₂)₃；

HFPO-C(O)N(CH₂CH₂OC(O)CH＝CH₂)₂；

HFPO-C(O)NHCH₂CH₂N(C(O)CH＝CH₂)CH₂OC(O)CH＝CH₂；

HFPO-C(O)NHCH(CH₂OC(O)CH＝CH₂)₂；

HFPO-C(O)NHC(CH₃)(CH₂OC(O)CH＝CH₂)₂；

HFPO-C(O)NHC(CH₂CH₃)(CH₂OC(O)CH＝CH₂)₂；

HFPO-C(O)NHCH₂CH(OC(O)CH＝CH₂)CH₂OC(O)CH＝CH₂；

HFPO-C(O)NHCH₂CH₂CH₂N(CH₂CH₂OC(O)CH＝CH₂)₂；

HFPO-C(O)OCH₂C(CH₂OC(O)CH＝CH₂)₃；

HFPO-C(O)NH(CH₂CH₂N(C(O)CH＝CH₂))₄CH₂CH₂NC(O)-HFPO；

CH₂＝CHC(O)OCH₂CH(OC(O)HFPO)CH₂OCH₂CH(OH)CH₂OCH₂CH(OC(O)HFPO)CH₂OCOCH＝CH₂；

HFPO-CH₂O-CH₂CH(OC(O)CH＝CH₂)CH₂OC(O)CH＝CH₂(ii) a And so on.

The above-mentioned polyfunctional perfluoropolyether (meth) acrylate can be synthesized, for example, by the following steps: the first step of reacting a poly (hexafluoropropylene oxide) ester such as HFPO-C (O) OCH₃Or poly (hexafluoropropylene oxide) acid halide: HFPO-c (o) F with a material comprising at least three alcohol or primary or secondary amino groups to produce HFPO-esters with HFPO-amide polyols or polyamines, HFPO-ester polyols or polyamines, HFPO-amides or mixed amine and alcohol groups, and a second step of (meth) acrylation of the alcohol groups and/or amine groups with (meth) acrylyl halides, (meth) acrylic anhydrides or (meth) acrylic acids. Alternatively, the multifunctional perfluoropolyether (meth) acrylates can be synthesized using Michael-type addition reactions of reactive perfluoroethers, such as HFPO-C (O) N (H) CH₂CH₂CH₂N(H)CH₃And trimethylolpropane triacrylate (TMPTA) and poly (meth) acrylate adducts.

The preferred polyfunctional fluorinated (meth) acrylic compound is a compound in which the perfluoroether moiety is divalent and the (meth) acrylic group is bonded to both terminals directly or through other groups or bonds (ether bond, ester bond, amide bond, urethane bond, etc.). While not being bound by any particular theory, it is believed that such compounds form strong bonds with the antireflective hardcoat to improve the durability of the antisoiling properties, and perfluoroether sites between (meth) acrylic groups migrate to the surface of the antireflective hardcoat to be easily oriented in the planar direction. Therefore, antifouling properties can be sufficiently exhibited.

The multifunctional fluorinated (meth) acrylic compound may comprise siloxane units. When the nanoparticles are inorganic oxides, the polyfunctional fluorinated (meth) acrylic compound containing siloxane units is more strongly bound to the antireflective hardcoat layer not only by the reaction between the (meth) acrylic groups and the curable monomer or curable oligomer but also by the interaction between the siloxane bonds and the nanoparticles, which is considered to further increase the durability of the antifouling property. The nanoparticles are preferably silica nanoparticles that are chemically similar and have a high affinity for siloxane bonds.

The polyfunctional fluorinated (meth) acrylic compound containing a siloxane unit can be synthesized, for example, by adding (hydrosilating) a perfluoropolyether compound having one or two or more unsaturated vinyl groups to a linear or cyclic oligosiloxane or a polysiloxane (hydrosiloxane) containing three or more Si-H bonds in the presence of a platinum catalyst or the like of less than one equivalent volume relative to the Si-H bonds, similarly adding (hydrosilating) an unsaturated vinyl compound containing a hydroxyl group to the remaining Si-H bonds in the presence of a platinum catalyst or the like, and then reacting the hydroxyl group with an epoxy (meth) acrylate, a polyurethane (meth) acrylate, or the like. The partial molecular weight of the perfluoroether site calculated from the chemical formula may be 500 to 30,000.

In order to sufficiently express the antifouling property imparted by the fluorinated site, the siloxane unit is preferably a cyclic siloxane unit derived from tetramethylcyclotetrasiloxane, pentamethylcyclopentasiloxane, or the like. The number of silicon atoms constituting the cyclic siloxane unit is preferably 3 to 7.

Examples of the polyfunctional fluorinated (meth) acrylic compound containing a siloxane unit are perfluoropolyether compounds having two or more (meth) acrylic groups described in, for example, japanese unexamined patent application publication 2010-285501. For example, the compounds of formula (19) and formula (21) in this publication have a structure in which a cyclic siloxane has four silicon atoms bonded to both ends of a divalent perfluoropolyether group, respectively: -CF₂(OCF₂CF₂)p(OCF₂)_qOCF₂- (p/q ═ 0.9, p + q ≈ 45), and three acryloyloxy groups bonded to each of these cyclic siloxanes through a urethane group, which are suitable for the antireflective hardcoat layer of the present disclosure.

The amount of the antifouling agent added may be, for example, in the range of about 0.01 to 20 parts by mass (in several embodiments, about 0.1 to 10 parts by mass or about 0.2 to 5 parts by mass) relative to 100 parts by mass of the total of the nanoparticles, the curable monomer, and the curable oligomer.

In some embodiments, the dehazer is included in the binder of the antireflective hardcoat. The antireflective hardcoat of this embodiment can inhibit condensation when the article comprising the antireflective hardcoat is used in an environment where temperature changes are substantial. The dehazer can be mixed with the curable monomer and curable oligomer. Anionic, cationic, nonionic or amphoteric surfactants can be used as the dehazing agent, and examples thereof include sorbitan surfactants such as sorbitan monostearate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monobehenate, and sorbitan, alkylene glycol condensate and fatty acid esters; a glycerol surfactant such as glycerol monopalmitate, glycerol monostearate, glycerol monolaurate, diglycerol monopalmitate, glycerol dipalmitate, glycerol distearate, glycerol monopalmitate/glycerol monostearate, triglycerol distearate, or alkylene oxide adducts thereof; polyethylene glycol surfactants such as polyethylene glycol monostearate, polyethylene glycol glycerol monopalmitate, and polyethylene glycol alkylphenyl ether; trimethylolpropane surfactants such as trimethylolpropane monostearate; pentaerythritol surfactants such as pentaerythritol glycerol monopalmitate and pentaerythritol monostearate; alkylene oxide adducts of alkyl phenols; esters of sorbitan/glycerol condensates with fatty acids and esters of sorbitan alkylene glycol condensates with fatty acids; diglycerol dialkoxide sodium lauryl sulfate, sodium dodecylbenzene sulfonate, cetyltrimethylammonium chloride, dodecylamine hydrochloride, laurylamide laurate ethylphosphate, triethylhexadecylammonium iodide, oleylaminodiethylamine hydrochloride, dodecylpyridine salt, and isomers thereof. The dehazer may additionally have functional groups that react with the curable monomer or curable oligomer.

The amount of the dehazing agent added may be, for example, in the range of about 0.01 to 20 parts by mass (in several embodiments, about 0.1 to 15 parts by mass or about 0.2 to 10 parts by mass) relative to 100 parts by mass of the total of the nanoparticles, the curable monomer, and the curable oligomer.

The hard coating precursor that can be used to form the antireflective hard coating layer comprises the above nanoparticle mixture, a curable monomer and/or curable oligomer, a reaction initiator, and, if necessary, a solvent such as Methyl Ethyl Ketone (MEK) or 1-methoxy-2-propanol (MP-OH), and the above additives such as a uv absorber, an antifouling agent, a defogging agent, a leveling agent, a uv reflecting agent, an antistatic agent, and the like. The hard coating precursor of some embodiments comprises a nanoparticle mixture and a binder, wherein the nanoparticles constitute 40 to 95 mass% of the total mass of the nanoparticles and the binder. 10 to 50 mass% of the nanoparticles have an average particle size in the range of 2 to 200nm, and 50 to 90 mass% of the nanoparticles have an average particle size in the range of 60 to 400 nm. The ratio of the average particle size of the nanoparticles having an average particle size in the range of 60nm to 400nm to the average particle size of the nanoparticles having an average particle size in the range of 2nm to 200nm is in the range of 2:1 to 200: 1.

As is generally known in the art, the hard coating precursor may be prepared by mixing the specific components of the hard coating precursor. For example, the hardcoat precursor can be prepared by preparing two or more different sized modified or unmodified nanoparticle sols having a desired solids content by mixing curable monomers and/or curable oligomers in a solvent along with a reaction initiator and adding the solvent. For example, a photoinitiator or a thermal polymerization initiator known in the art may be used as the reaction initiator. Depending on the curable monomer and/or curable oligomer used, the use of a solvent may not be necessary.

When surface-modified nanoparticles are used, for example, a hard coating precursor may be prepared as follows. The inhibitor and the surface modifier are added to a solvent in a container (e.g., in a glass vial), and the resulting mixture is added to an aqueous solution in which the nanoparticles are dispersed, and then stirred. The container is sealed and placed in an oven at elevated temperature (e.g., 80 ℃) for several hours (e.g., 16 hours). Next, water is removed from the solution at an elevated temperature (e.g., 60 ℃) using, for example, a rotary evaporator. The remaining water was removed from the solution by pouring the solvent into the solution and then evaporating the solution. It is sometimes preferred to repeat the latter half of the steps several times. By adjusting the volume of the solvent, the concentration of the nanoparticles can be adjusted to a desired concentration (mass%).

Techniques for applying a hard coat precursor (solution) to a substrate surface are known in the art, and examples include bar coating, dip coating, spin coating, capillary coating, spray coating, gravure coating, screen printing, and the like. The coated hard coat precursor is dried as needed, and it may be cured using polymerization methods known in the art such as optical polymerization using ultraviolet rays or electron beams, thermal polymerization, or the like. In this way, a hard coat layer can be formed on the substrate.

Next, dry etching is performed on the hard coat layer surface. As a result of the dry etching, the binder is preferentially etched when the nanoparticles serve as an etching mask, thus producing a moth-eye structure having a plurality of prism structures on the hard coat layer surface. The dry etching used may be of the dry etching type well known in the art, and examples include methods such as ion etching, plasma etching, radical etching, Reactive Ion Etching (RIE), Reactive Ion Beam Etching (RIBE), plasma etching, molecular beam etching, atmospheric pressure plasma treatment, air corona treatment, and the like. From the viewpoints of minimizing damage to the substrate, good in-plane uniformity, high etching perpendicular anisotropy, and high yield, plasma etching, Reactive Ion Etching (RIE), and Reactive Ion Beam Etching (RIBE) are preferable, and plasma etching is particularly advantageously used. The dry etch may be performed over the entire hard coat surface or only partially over the desired area of the hard coat surface. For example, dry etching may be selectively performed on the hard coat layer surface by masking regions that are not required to have an antireflection function or adhesion.

Depending on the type of dry etching, various process pressure conditions in the range of atmospheric pressure to vacuum may be used. For example, when performing plasma etching or reactive ion etching, the pressure can be set to at least about 1mTorr (about 0.13Pa) or at least about 5mTorr (about 0.67Pa) and at most about 20mTorr (about 2.7Pa) or at most about 10mmTorr (about 1.3 Pa).

Typical etching gases that may be used in dry etching include ArO₂、H₂、CF₄、C₂F₆、C₃F₈、CHF₃、CH₂F₂、CF₃Br、N₂、NF₃、Cl₂、CCl₄、HBr、SF₆And so on. The flow rate of the etching gas is adjusted according to various conditions such as the type of dry etching, the volume of the chamber used, the electrode area, the pressure inside the chamber, and the like. For example, when performing plasma etching or reactive ion etching, the flow rate can be set to at least about 1sccm or at least about 5sccm and at most about 1000sccm or up to about 200 sccm.

The frequency of the RF (radio frequency) power oscillator that can be used in dry etching is typically 13.56MHz, but other frequencies can be used. For example, when using a capacitively coupled vacuum plasma with an oscillation frequency of 13.56MHz, the RF power output is typically in the range of about 100W to 20kW, and the power density is preferably in the range of about 0.1 to 1.0 watts per square centimeter (in several embodiments, about 0.2 to 0.3 watts per square centimeter).

The dry etching temperature is determined so that the hard coating layer and the substrate are not excessively damaged, and is in the range of about-60 ℃ to 100 ℃. The dry etching time is determined such that the etching depth of the hard coating layer is about 10 to 500nm, and the dry etching time is generally in the range of about 1 second to 2 minutes.

Since the antireflective hard coating layer of the present disclosure is filled with high levels of nanoparticles, the depth of the plurality of recesses formed after dry etching is less than the wavelength of visible light, and is preferably 1/4 up to the wavelength of visible light, such as, for example, 100nm to 200nm or less. Therefore, the antireflective hard coating layer exhibits antireflective characteristics and exhibits excellent scratch resistance due to the relatively large amount of nanoparticles remaining on the dry-etched surface.

In the antireflective hardcoat of the present disclosure, the dry etching causes an increase in the exposed area of the nanoparticles, and thus a silane coupling process may also be performed on the dry-etched surface, if necessary. Such silane coupling treatment makes it possible to also provide other functions to the surface of the antireflective hardcoat, such as stain resistance or fog resistance.

The silane coupling treatment may be performed by a known method using a hydrophilic or hydrophobic silane coupling agent. Examples of the hydrophilic silane coupling agent include amino-modified alkoxysilanes, epoxy resin-modified alkoxysilanes such as glycidyl-modified alkoxysilanes, polyether-modified alkoxysilanes, zwitterionic alkoxysilanes, and the like. Examples of the hydrophobic silane coupling agent include chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, and allylphenyldichlorosilane, hexamethyldisilazane, alkylalkoxysilanes, phenylalkoxysilanes, vinylalkoxysilanes, and the like.

The hydrophilicity may also be enhanced by applying a modified silicone oil such as an amino-modified silicone oil or an epoxy-modified silicone oil to the silane coupling treated surface. Hydrophobicity can also be enhanced by applying dimethyl silicone oil, methylphenyl silicone oil, alkyl-modified silicone oil, or the like to the silane coupling treated surface.

One embodiment of the present disclosure provides an antireflective article having a layer of the aforementioned antireflective hardcoat on the surface of a substrate. In the antireflective article 10 of the embodiment of the disclosure shown in fig. 2, a hard coat layer 14 having a dry etched surface 15 is disposed on a first surface of a substrate 12. Examples of substrates that can be used in the antireflective article include transparent substrates such as films, plastics (polymer sheets), glass sheets. In the present disclosure, "transparent" means that the total light transmittance in the visible light range (380nm to 780nm) is at least 90%. Examples of representative films include films formed from: polyolefins (e.g., Polyethylene (PE), polypropylene (PP), etc.), polyurethanes, polyesters (e.g., polyethylene terephthalate (PET), etc.), poly (meth) acrylates (e.g., polymethyl methacrylate (PMMA), etc.), polyvinyl chloride, polycarbonates, polyamides, polyimides, phenol resins, cellulose diacetate, cellulose triacetate, polystyrene, styrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene copolymers (ABS), epoxy resins, polyacetates, or glass. Examples of representative plastics (polymer sheets) include plastics formed from: polycarbonate (PC), Polymethylmethacrylate (PMMA), styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), a blend of PC and PMMA or a laminate of PC and PMMA.

The thickness of the thin film is in the range of about 5 μm to 500 μm (in several embodiments, about 10 μm to 200 μm or about 25 μm to 100 μm). The thickness of the plastic (polymer sheet) is in the range of about 0.5mm to 10cm (in several embodiments, about 0.5mm to 5mm or about 0.5mm to 3 mm). The thickness of the glass sheet is in a range from about 5 μm to 500 μm or from about 0.5mm to 10cm (in several embodiments, from about 0.5mm to 5mm or from about 0.5 to 3 mm). Even when the thickness deviates from the above range, these substrates can sometimes be effectively used.

The antireflective article can have the aforementioned antireflective coating on multiple surfaces of the substrate. For example, the substrate may have a first surface and a second surface, and the aforementioned antireflective hardcoat layer may be disposed on the first surface and the second surface of the substrate. The second surface may be disposed on an opposite side of the first surface when viewed from the substrate. That is, the first surface and the second surface may be two opposing surfaces of the substrate. In the antireflective article 20 shown in fig. 3, for example, a hard coat layer 24 having a dry-etched surface 25 is provided on a first surface and a second surface opposite the first surface of the substrate 22, respectively. When a plurality of antireflective hardcoats are used in this manner, the antireflective properties of the antireflective article can be enhanced. A laminate of a plurality of antireflective hardcoats may also be disposed on the surface of the substrate.

In several embodiments, to improve the adhesion of the antireflective hardcoat layer to the substrate, the surface of the substrate is primed or a primer layer is disposed on the surface of the substrate. In particular, priming or primer layers are particularly effective when the substrate is a poorly adherent film such as polypropylene, polyvinyl chloride, and the like.

Priming is known in the art, and examples include plasma treatment, corona discharge treatment, flame treatment, electron beam irradiation, surface roughening, ozone treatment, chemical oxidation treatment using chromic acid or sulfuric acid, and the like.

Examples of the material for the primer layer include (meth) acrylic resins ((homopolymers of (meth) acrylic esters, copolymers of two or more types of (meth) acrylic esters, or copolymers of (meth) acrylic esters and other polymerizable monomers), polyurethane resins (e.g., 2-solution curable polyurethane resins composed of a polyol and an isocyanate curing agent), (meth) acryl-polyurethane copolymers (e.g., acryl-polyurethane block copolymers), polyester resins, butyral resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate copolymers, chlorinated polyolefins such as chlorinated polyethylene or chlorinated polypropylene, and copolymers and derivatives thereof (e.g., chlorinated ethylene-propylene copolymers, chlorinated ethylene-vinyl acetate copolymers, chlorinated polypropylene, and copolymers and derivatives thereof, Chlorinated ethylene-vinyl acetate copolymer, acryl-modified chlorinated polypropylene, maleic anhydride-modified chlorinated polypropylene, and polyurethane-modified chlorinated polypropylene), and the like. When the substrate is a polypropylene film, it is advantageous that the primer comprises chlorinated polypropylene or modified chlorinated polypropylene.

The primer layer may be formed by applying a primer solution prepared by dissolving the aforementioned resin in a solvent using a method known in the art and then drying the solution. The thickness of the primer layer is typically in the range of about 0.1 μm to 20 μm (in several embodiments, about 0.5 μm to 5 μm).

In some embodiments, the antireflective article may have an adhesive layer on the dry etched surface. The dry-etched surface has a precise surface roughness, resulting in excellent adhesion by the adhesive layer. In this embodiment, the use of the adhesive layer makes it possible to easily provide other articles having antireflection characteristics. Rubber adhesives, acrylic adhesives, polyurethane adhesives, polyolefin adhesives, polyester adhesives, and silicon adhesives or pressure sensitive adhesives known in the art may be used as the adhesive layer. The adhesive or pressure sensitive adhesive is preferably an optically clear adhesive or pressure sensitive adhesive, such as an optically clear acrylic adhesive or pressure sensitive adhesive. In the present disclosure, "optically transparent" means that the total light transmittance in the visible light range (380nm to 780nm) is at least 90% and, if necessary, the total light transmittance of light of other wavelength ranges (e.g., ultraviolet range) is also at least 90%. The adhesive layer may be formed by applying or extruding the adhesive and pressure sensitive adhesive directly onto the substrate, or the adhesive layer may be formed by applying the adhesive and pressure sensitive adhesive onto a release liner that may be laminated and transferred to the substrate.

The thickness of the adhesive layer comprising the adhesive or pressure sensitive adhesive is typically in the range of about 1 μm to 100 μm (in several embodiments, about 5 μm to 75 μm or about 10 μm to 50 μm). The adhesive or pressure sensitive adhesive may also contain the above-mentioned ultraviolet absorbers.

If necessary, the antireflective hardcoat and/or adhesive layer may also have a release liner as is known in the art. Materials known in the art and prepared by performing a silicon treatment or the like on paper or a polymer film may be used as the release liner.

In some embodiments, the antireflective article can further comprise a second substrate laminated on the dry etched surface independent of the substrate supporting the antireflective hardcoat. For example, such a second substrate may be laminated on the dry etched surface by the adhesive layer described above. The adhesive layer is preferably formed using an optically clear adhesive or a pressure sensitive adhesive.

Cross-sectional views of display cells 30,40, and 50 in which the second substrate is a liquid crystal display panel 37,47, and 57 are shown in fig. 4 through 6 as examples of using the antireflective article of the present disclosure. In fig. 4, a hard coat layer 34 is provided on both sides of a substrate 32, and a part of a dry-etched surface 35 and a liquid crystal display panel 37 are attached to each other by an optically transparent adhesive layer 36. In fig. 4, a printed layer 38 is provided at the outer periphery of the dry-etched surface 35 as a frame of an image display region of the liquid crystal display panel 37. Dry-etched surface 35 having precise surface roughness also has excellent printing characteristics with respect to the printing ink or the like used to form printed layer 38. In fig. 5, the hard coating layer 44 on both sides of the substrate 42 has a dry-etched surface 45, and thus the anti-reflection property is further improved compared to fig. 4. In fig. 6, a silane coupling process is also performed on a dry-etched surface 59 located on the opposite side of the liquid crystal display panel 57 in order to provide a surface of the display unit having functionality such as stain resistance, fog resistance, and the like.

For example, the antireflective hard coating and antireflective article of the present disclosure are suitable for various applications such as liquid crystal displays, EL displays, LED displays, plasma displays, touch panels, lenses for cameras, and the like, solar power panels (solar panels), and the like. However, the antireflective hardcoats and antireflective articles of the present disclosure are not limited to these applications and may be used in a variety of applications where antireflective properties are desired.

The present disclosure provides various embodiments of antireflective hardcoats, articles, and displays.

Example 1 is an antireflective hardcoat comprising a nanoparticle mixture and a binder, the antireflective hardcoat having a dry etched surface; the nanoparticles constitute 40 to 95 mass% of the entire mass of the hard coat layer; 10 to 50 mass% of the nanoparticles have an average particle size in the range of 2 to 200 nm; 50 to 90 mass% of the nanoparticles have an average particle size in the range of 60 to 400 nm; the ratio of the average particle size of the nanoparticles having an average particle size in the range of 60nm to 400nm to the average particle size of the nanoparticles having an average particle size in the range of 2nm to 200nm is in the range of 2:1 to 200:1, wherein the particle size distribution of the nanoparticles is bimodal or multimodal.

Embodiment 2 is the antireflective hardcoat of embodiment 1 wherein the nanoparticles are surface modified nanoparticles.

Embodiment 3 is the antireflective hardcoat of embodiment 1 or embodiment 2 wherein the dry etch is a plasma etch.

Embodiment 4 is the antireflective hardcoat of any one of embodiments 1 to 3 wherein the binder comprises a fluorinated (meth) acrylic compound, a reaction product thereof, or a combination thereof.

Embodiment 5 is the antireflective hardcoat of any of embodiments 1 through 4 wherein a silane coupling treatment is also performed on the dry etched surface.

Example 6 is a composition comprising a substrate having a first surface; and a layer of the antireflective hardcoat of any one of examples 1-5 disposed on the first surface of the substrate.

Embodiment 7 is the antireflective article of any one of embodiments 1 to 6, wherein the substrate further comprises a second surface and further comprises a layer of the antireflective hardcoat of any one of embodiments 1 to 5 disposed on the second surface of the substrate.

Embodiment 8 is the antireflective article of any one of embodiments 1 through 7, wherein a second substrate is laminated on the dry etched surface.

Embodiment 9 is the antireflective article of any one of embodiments 1 through 8, wherein a second substrate is laminated on the dry etched surface through an optically clear adhesive layer.

Embodiment 10 is a display unit comprising the antireflective article of any one of embodiments 1 through 9, wherein the second substrate is a liquid crystal display panel.

Examples of the invention

The following examples illustrate specific embodiments of the present disclosure, but the present invention is not limited to these embodiments. All "parts" and "percentages" are by mass unless otherwise specified.

Evaluation methodMethod of

The characteristics of the antireflective hardcoat of the present disclosure were evaluated according to the following methods.

1. Optical characteristics

The transmittance at wavelengths of 350 to 850nm was measured using a UV-vis spectrophotometer (U-4100, available from Hitachihigh Technologies Corporation).

2. Contact angle

The water contact angle of the antireflective hardcoat surface was measured by sessile drop method using a contact angle meter (obtained by Kyowa Kaimen Kagaku co., Ltd.) under the product name "DROPMASTER FACE"). For the measurement of the static contact angle, the volume of the liquid droplet was set to 4 μ L. The value of the water contact angle was calculated from the average of five measurements. A surface having a water contact angle exceeding 100 degrees may prevent deposition of dust and the like. On the other hand, a surface having a water contact angle of less than 20 degrees has high hydrophilicity, which can prevent fogging due to condensation of water vapor on the surface.

3. Adhesion testing

An optically clear adhesive tape (CEF0806, from 3M Company (3M Company)) having a width of 25nm was attached to the antireflective hardcoat surface of each substrate using a 2.0kg roll, and the adhesive force was measured at 25 ℃ at a peel angle of 90 degrees and a peel rate of 300 mm/min.

Table 1: reagents and raw materials

Surface-modified silica sols (Sol 1)Preparation of

A surface-modified silica sol ("sol 1") was prepared as follows. First, 5.95g of SILQUEST A174 and 0.5g of PROSTAB were added to a mixture of 400g of NALCO 2329 and 450g of 1-methoxy-2-propanol in a glass vial and stirred at room temperature for 10 minutes. The glass vial was sealed and placed in an oven at 80 ℃ for 16 hours. Water was removed from the resulting solution with a rotary evaporator until the solid content of the solution at 60 ℃ reached almost 45 mass%. Two hundred grams of 1-methoxy-2-propanol were added to the resulting solution and the remaining water was removed using a rotary evaporator at 60 ℃. The second half of the procedure was repeated twice to further remove the water from the solution. Finally, all SiO was removed by addition of 1-methoxy-2-propanol₂The concentration of the nanoparticles was adjusted to 45 mass%, and SiO containing surface modification was obtained₂SiO of nanoparticles₂Sol (hereinafter referred to as "sol 1") in which the nanoparticles have an average particle size of 75 nm.

Preparation of surface-modified silica Sol (Sol 2)

A surface-modified silica sol ("sol 2") was prepared as follows. The modification was carried out in the same manner as in sol 1, except that 400g of NALCO 2327, 25.25g of SILQUEST A174 and 0.5g of PROSTAB were used, and a surface-modified SiO solution containing 45 mass% of SiO was obtained₂SiO of nanoparticles₂Sol (hereinafter referred to as "sol 2") in which the nanoparticles have an average particle size of 20 nm.

Preparation of surface-modified silica Sol (Sol 3)

A surface-modified silica sol ("sol 3") was prepared as follows. The modification was carried out in the same manner as in sol 1, except that 400g of MP-2040, 4.74g of SILQUESTA174 and 0.5g of PROSTAB were used, and a surface-modified SiO solution containing 45 mass% was obtained₂SiO of nanoparticles₂Sol (hereinafter referred to as "sol 3") in which the nanoparticles have an average particle size of 190 nm.

Example 1

Sol 1 and sol 2 were mixed at a ratio (mass ratio) of 65:35, and the amount of 1-methoxy-2-propanol was adjusted to obtain a mixture containing 46.65 mass% of surface-modified nanoparticles in total. The binder was prepared by mixing EBECRYL 4858, SR340 and IRGACURE 184 in a ratio (mass ratio) of 90:10: 8. The mixture comprising the surface-modified nanoparticles and the binder were mixed in a ratio (mass ratio) of 75: 25. The resulting antireflective hardcoat composition was applied to a 2mm thick glass sheet (white glass sheet, available from shoddy AG) using a #4Meyer rod and dried at 40 ℃ for 10 minutes. Next, the composition was irradiated with ultraviolet rays having a wavelength of 253.7nm for 5 minutes (dose: 268.43 mJ/cm) using a 25W UV lamp (germicidal lamp G25T8, available from Sankyo Denki) in a nitrogen-containing atmosphere²). This formed a hard coat layer of example 1 on the glass sheet. The base pressure inside the chamber was then set to 10mTorr using a PDC210 plasma treatment apparatus (obtained from Yamato Scientific co., Ltd.) and then at 25 ℃ at 13.56MHz, 200W power and 28.7J/cm²Plasma etching was performed on the hard coat surface for 60 seconds while maintaining the pressure inside the chamber at 46mTorr to 48mTorr with an oxygen flow rate of 73sccm to prepare a sample for transmittance measurement.

Example 2

A sample for transmittance measurement was prepared in the same manner as in example 1, except that the ratio of the mixture containing the surface-modified nanoparticles to the binder was set to 69:31 (mass ratio).

Example 3

A sample for transmittance measurement was prepared in the same manner as in example 1, except that the ratio of the mixture containing the surface-modified nanoparticles to the binder was set to 65:35 (mass ratio).

Example 4

A sample for transmittance measurement was prepared in the same manner as in example 1, except that sol 3 was used instead of sol 1 and a Glass sheet (float Glass, obtained from Asahi Glass co., Ltd.) having a thickness of 2mm was used.

Comparative examples 1 to 4

Samples for transmittance measurement in comparative examples 1 to 4 were prepared by the same procedure as in examples 1 to 4, respectively, except that plasma etching was not performed on the hard coat layer surface.

The results of measuring the optical characteristics of the samples of examples 1 to 4 and comparative examples 1 to 4 are shown in fig. 7 to 10.

Preparation of hard coating precursor (HC-1)

First, 108.33g of sol 1, 58.33g of sol 2 and 25g of Kayurad UX-5000 were mixed. Next, 2.0g of IRGACURE 184 as an optical polymerization initiator was added to the mixture, and 0.01g of BYK-UV3500 as a leveling agent was added to the mixture. Then, the mixture was adjusted to have a solid content of 50 mass% by adding 1-methoxy-2-propanol, thereby preparing a hard coat precursor HC-1.

Preparation of hardcoat precursors (HC-2 and HC-3)

Hard coat precursors HC-2 and HC-3 were prepared in the same manner as HC-1 using the formulations described in Table 2. HFPO urethane acrylate was added to HC-2 as an antifouling agent, and KY-1203 was added to HC-3.

The compositions of HC-1 to HC-3 are shown in Table 2.

TABLE 2

Hard coat precursor composition (mixing amount is expressed in grams)

Example 5

A polycarbonate substrate (100 × 53 × 1mm, available under the product name "Lupilon NF 2000" from Mitsubishi gas chemical Company, Inc.) was suspended from the head of the dip coater and fixed to the head of the dip coater, and immersed in the hard coat precursor HC-1. After 30 seconds, the substrate was pulled up at a rate of 3.33 mm/sec. After drying the substrate at 60 ℃ for 5 minutes, the substrate was placed in a nitrogen purged box with an oxygen concentration of 50 ppm. Next, the substrate was irradiated with ultraviolet rays having a wavelength of 253.7nm for 5 minutes from both sides using a 25W UV lamp (germicidal lamp G25T8, available from Sankyo Denki) in a nitrogen-containing atmosphere (irradiation amount: 268.43 mJ/cm)²). The base pressure inside the chamber was set to 10mTorr using a PDC210 plasma treatment apparatus (obtained from Yamato Scientific co., Ltd.) and then at 25 ℃ at 13.56MHz, 200W power and 28.3J/cm²Plasma etching was performed on the hard coat surface for 60 seconds while maintaining the pressure inside the chamber at 46mTorr to 48mTorr with an oxygen flow rate of 73 seem.

Example 6

The hard coat precursor HC-1 was applied and cured in the same manner as in example 5. Plasma etching was performed on both sides of the sample under the same conditions as in example 5.

Example 7

The hard coat precursor HC-1 was applied and cured in the same manner as in example 5. Plasma etching was performed on both sides of the sample under the same conditions as in example 5. After plasma etching, a hydrophobic silane coupling agent EGC1720 was applied to one surface and cured by heating at 100 ℃ for 30 minutes.

Example 8

The hard coat precursor HC-1 was applied and cured in the same manner as in example 5. Plasma etching was performed on both sides of the sample under the same conditions as in example 5. After plasma etching, a hydrophilic silane coupling agent L-21074 was applied to one surface and cured by heating at 100 ℃ for 30 minutes.

Examples 9 and 10

The hard coat precursor HC-2 was applied and cured in the same manner as in example 5. Plasma etching was performed on one side (example 9) or both sides (example 10) of the sample under the same conditions as in example 5.

Examples 11 and 12

The hard coat precursor HC-3 was applied and cured in the same manner as in example 5. Plasma etching was performed on one side (example 11) or both sides (example 12) of the sample under the same conditions as in example 5.

Comparative examples 5 to 8

An untreated polycarbonate substrate (100 × 53 × 1mm, available under the product name "Lupilon NF 2000" from Mitsubishi gas chemical Company, Inc.) was used as comparative example 5, and substrates in which plasma etching was not performed after the hard coat precursor was applied and cured in the same manner as in examples 5, 9 and 11 were used as comparative examples 6 to 8, respectively.

The results of evaluating these hard coatings are shown in table 3 and fig. 11 to 13.

Table 3: surface properties of plasma etched antireflective hardcoats and untreated hardcoats

As shown in fig. 7 to 13, the reflectivity of the hard coating surface decreases and the transmittance of the hard coating increases due to the plasma etching. In particular, the hard coatings plasma etched on both sides showed about 5% higher transmission than those not plasma etched.

Table 3 shows the water contact angle and adhesion force before and after plasma etching. Hardcoats with anti-fouling agents and without plasma etching (comparative examples 7 and 8) showed water contact angles in excess of 100 degrees. Example 7, subjected to a hydrophobic silane coupling treatment, also shows a water contact angle in excess of 100 degrees. On the other hand, example 8, which was subjected to the hydrophilic silane coupling treatment, had a water contact angle of less than 20 degrees. These results indicate that further performing a silane coupling treatment on the plasma-etched surface makes it possible to provide an antireflective hard coating having stain resistance or fog resistance.

After plasma etching, the adhesion of the optically clear adhesive increased (comparative examples 6 and 5, comparative examples 7 and 9, and comparative examples 8 and 11). These results indicate that the dry-etched surface of the antireflective hardcoat of the present disclosure has excellent adhesion of the binder and printing suitability for printing ink and the like.

Interpretation of identification numbers：

10,20 antireflective articles

12,22 base material

14,24 hard coating

15,25 dry etched surfaces

30,40,50 liquid crystal display

32,42,52 base material

34,44,54 hard coating

35,45,55 dry etched surfaces

36,46,56 optically clear adhesive layer

37,47,57 liquid crystal display panel

38,48,58 print layer

59 dry etched and silane coupling treated surface

Claims (10)

1. An antireflective hardcoat comprising a nanoparticle mixture and a binder, the antireflective hardcoat having a dry etched surface;

the nanoparticles constitute 40 to 95 mass% of the entire mass of the hard coat layer;

10 to 50 mass% of the nanoparticles have an average particle size in the range of 2 to 200 nm;

50 to 90 mass% of the nanoparticles have an average particle size in the range of 60 to 400 nm;

a ratio of the average particle size of nanoparticles having an average particle size in the range of 60nm to 400nm to the average particle size of nanoparticles having an average particle size in the range of 2nm to 200nm is in the range of 2:1 to 200:1,

wherein the particle size distribution of the nanoparticles is bimodal or multimodal.

2. The antireflective hardcoat of claim 1 wherein the nanoparticles are surface modified nanoparticles.

3. The antireflective hardcoat of claim 1 or 2 wherein the dry etch is a plasma etch.

4. The antireflective hardcoat of any one of claims 1 to 3 wherein the binder comprises a fluorinated (meth) acrylic compound, a reaction product thereof, or a combination thereof.

5. The antireflective hardcoat of any one of claims 1 to 4 wherein a silane coupling treatment is also performed on the dry etched surface.

6. An antireflective article, comprising: a substrate having a first surface; and

a layer of the antireflective hardcoat of any one of claims 1 to 5 disposed on the first surface of the substrate.

7. The antireflective article according to claim 6, wherein the substrate further comprises a second surface and further comprising a layer of the antireflective hardcoat according to any one of claims 1 to 5 disposed on the second surface of the substrate.

8. The antireflective article of claim 6 or 7 wherein a second substrate is laminated on the dry etched surface.

9. The antireflective article of claim 8 wherein the second substrate is laminated on the dry etched surface by an optically clear adhesive layer.

10. A display unit comprising the antireflective article of claim 8 or 9, wherein the second substrate is a liquid crystal display panel.