JP2014133393A - Front substrate for touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front substrate for a touch panel with a hard coat layer having preferable slipperiness.SOLUTION: A front substrate for a touch panel includes a substrate, and a hard coat layer formed on the substrate, wherein the hard coat layer contains a fluorine silicone-based surfactant.

Description

  The present invention relates to a front substrate for a touch panel having a hard coat layer with good slipperiness.

  Today, touch panels are widely used as input means. In many cases, the touch panel is used together with the display device as an input means for various devices in which a display device such as a liquid crystal display or a plasma display is incorporated, for example, a ticket machine, an ATM device, a mobile phone, a game machine or the like. . In such a device, the touch panel is arranged on the display surface of the display device, which allows the touch panel to make a very direct input to the display device.

Generally, in a touch panel, a front substrate is disposed on the outermost surface for surface protection. Conventionally, tempered glass has been used for the front substrate, but tempered glass has problems such as being heavy and breaking. Therefore, a change from tempered glass to a transparent resin substrate has been studied. On the other hand, the transparent resin substrate has the advantage of being light and difficult to break, but has the disadvantage that the surface is easily damaged.
In addition, since many touch panels are used by directly bringing a finger into contact with the front substrate, the front substrate is required to have good scratch resistance and antifouling properties.

  By the way, in the front substrate used for a display apparatus, the technique which coats and hardens | cures the curable resin composition on the surface of a transparent resin substrate, forms a hard-coat layer, and improves abrasion resistance is proposed. For example, in Patent Document 1, it is possible to improve the scratch resistance of the front substrate by using a configuration in which a heat-resistant acrylic resin layer is formed on at least one side of the polycarbonate resin layer as the configuration of the substrate used for the front substrate. Is disclosed. Patent Documents 2 to 4 disclose that the scratch resistance of the front substrate can be improved by using a hard coat layer formed by curing a curable composition to which reactive irregularly shaped silica fine particles are added. Has been. Moreover, in patent document 5, the fingerprint of a front substrate is used by using the hard-coat layer formed by hardening | curing curable resin composition containing an inorganic oxide particle, a specific compound, a specific fatty acid ester type surfactant, etc. It is disclosed that visibility, fingerprint wiping property, and wear resistance can be improved.

JP 2009-279806 A JP 2010-102123 A JP 2010-120182 A International Publication No. 2012/018009 Pamphlet JP 2012-148484 A

  By the way, as a touch operation of the touch panel, in addition to tapping the operation screen lightly, recently, dragging the operation screen with a finger, flicking the operation screen lightly with a finger, and between two fingers touching the operation screen For example, a pinch-in operation that shortens the distance between the two fingers and a pinch-out operation that increases the distance between two fingers that touch the operation screen are used to move the finger while touching the operation screen. In such a touch operation, there is a concern that the touch operation cannot be smoothly performed or a malfunction occurs due to the movement of the finger on the surface of the front substrate. Therefore, the front substrate of the touch panel is required to have good slipperiness such as a finger on the surface, that is, easy slipperiness.

  This invention is made | formed in view of the said situation, and it aims at providing the front substrate for touchscreens which has a hard-coat layer with favorable slidability.

  As a result of intensive studies to solve the above problems, the inventors of the present invention can obtain a hard coat layer exhibiting good slipperiness by containing a fluorosilicone surfactant in the hard coat layer. As a result, the present invention has been completed.

  In order to solve the above-mentioned problem, the present invention is a front substrate for a touch panel having a substrate and a hard coat layer formed on the substrate, wherein the hard coat layer contains a fluorosilicone surfactant. Provided is a front substrate for a touch panel.

  ADVANTAGE OF THE INVENTION According to this invention, the said hard-coat layer can provide the front substrate for touchscreens which has a hard-coat layer with favorable slidability by containing a fluorine-silicon-type surfactant.

  The front substrate for a touch panel of the present invention has an operational effect that the slidability of the hard coat layer is good.

It is a schematic sectional drawing which shows an example of the front substrate for touchscreens of this invention. It is a schematic sectional drawing which shows the other example of the front substrate for touchscreens of this invention. It is a schematic sectional drawing which shows the other example of the front substrate for touchscreens of this invention.

Hereinafter, the front substrate for a touch panel of the present invention will be described.
The front substrate for a touch panel of the present invention comprises a substrate and a hard coat layer formed on the substrate, wherein the hard coat layer contains a fluorosilicone surfactant. Is.

  FIG. 1 is a schematic cross-sectional view showing an example of a front substrate for a touch panel according to the present invention. As illustrated in FIG. 1, the touch panel front substrate 10 of the present invention includes a substrate 1 and a hard coat layer 2 formed on the substrate 1. Further, the hard coat layer 2 contains a fluorosilicone surfactant.

According to this invention, it can be set as the front substrate for touchscreens which has a hard-coat layer with favorable slipperiness, when a hard-coat layer contains a fluorosilicone surfactant.
Moreover, according to this invention, antifouling property can be provided to a hard-coat layer because a hard-coat layer contains a fluorine silicon type surfactant.
Hereinafter, the details of the front substrate for a touch panel of the present invention will be described.

1. Hard coat layer The hard coat layer in the present invention contains a fluorosilicone surfactant.
The hard coat layer is usually composed of a cured product of a curable resin composition containing a fluorosilicone surfactant, inorganic oxide fine particles, a polymer, a monomer, and a polymerization initiator. Hereinafter, the curable resin composition will be described.

(1) Curable resin composition The curable resin composition used in the present invention contains a fluorosilicone surfactant, inorganic oxide fine particles, a polymer, a monomer, and a polymerization initiator.

(A) Fluorosilicon-based surfactant The fluorinated silicon-based surfactant contained in the curable resin composition is a component that imparts lubricity to the hard coat layer.
Examples of the fluorosilicone surfactant include a compound having a perfluoroalkyl group and a siloxane bond. Specifically, a compound having a perfluoroalkyl group and a copolymer of siloxane and polyether. Is mentioned. The carbon number of the perfluoroalkyl group is, for example, 4 to 10. The perfluoroalkyl group may be linear or branched. Examples of the polyether group include a polyethylene oxide chain, a polypropylene oxide chain, and a copolymer thereof.

  Specific examples of such a fluorosilicone surfactant include compounds represented by the following chemical formula (1).

  In the above formula (1), R is a perfluoroalkyl group having 4 to 10 carbon atoms, Q is a polyethylene oxide chain or a polypropylene oxide chain, k and m are each 0 or 1, and n is 1, 2 or 3 It is.

  In addition, the fluorosilicone surfactant may have a reactive functional group. As the reactive functional group, for example, a polymerizable unsaturated group is used. Specifically, a photocurable unsaturated group may be used, and more specifically, an ionizing radiation curable unsaturated group may be used. . Specifically, a (meth) acryloyl group may be used as the reactive functional group.

  Specific examples of the fluorosilicone surfactant include X-71-1203M, X-70-090, X-70-091, X-70-092, X-70-093, manufactured by Shin-Etsu Chemical Co., Ltd., DIC Corporation. Examples thereof include Megafac R-08, XRB-4, and the like.

  The content of the fluorosilicone surfactant is preferably 1% by mass or less, more preferably 0.2% by mass or less, and more preferably 0.08% by mass with respect to the total solid content of the curable resin composition. It is particularly preferable that the content be in the range of% to 0.1% by mass. When the content of the fluorosilicone surfactant is within the above range, desired slipperiness can be imparted to the hard coat layer.

(B) Inorganic oxide fine particle In this invention, an inorganic oxide fine particle is a component which contributes to the hardness improvement of a hard-coat layer.

Examples of the inorganic oxide used for the inorganic oxide fine particles include silica, alumina, zirconia, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, tin-containing indium oxide, antimony oxide, and cerium oxide. Among these, silica is preferable.
Further, as the silica fine particles, it is preferable to use reactive silica fine particles having a reactive functional group.

  The reactive silica fine particles usually have a reactive functional group. As the reactive functional group, a polymerizable unsaturated group is suitably used, preferably a photocurable unsaturated group, and particularly preferably an ionizing radiation curable unsaturated group. Specific examples thereof include ethylenically unsaturated bonds such as (meth) acryloyl group, vinyl group and allyl group, and epoxy group.

  In the present specification, (meth) acryloyl means at least one of acryloyl and methacryloyl, (meth) acrylate means at least one of acrylate and methacrylate, and (meth) acryl is at least one of acrylic and methacrylic. Means.

  Further, the reactive silica fine particles may be spherical reactive silica fine particles, or irregular-shaped reactive silica fine particles (hereinafter sometimes referred to as reactive irregular-shaped silica fine particles). The latter is preferred. This is because it is easy to improve the hardness of the hard coat layer.

  Examples of the reactive irregularly shaped silica fine particles include reactive irregularly shaped silica fine particles in which a plurality of silica fine particles are bonded by an inorganic chemical bond. In particular, the reactive irregularly shaped silica fine particles are reactive irregularly shaped silica fine particles having 3 to 20 silica fine particles having an average primary particle diameter of 1 nm to 100 nm bonded by an inorganic chemical bond and having a reactive functional group on the surface. Is preferred. The reactive irregularly shaped silica fine particles have a reactive functional group, so that they can undergo a curing reaction that crosslinks with the reactive irregularly shaped silica fine particles and the monomer, and can impart scratch resistance and hardness to the hard coat layer. .

The average primary particle size of the silica fine particles constituting the reactive irregularly shaped silica fine particles is preferably in the range of 1 nm to 100 nm, and more preferably in the range of 5 nm to 80 nm. If the average primary particle size of the silica fine particles is small, only reactive irregularly shaped silica fine particles having a small average secondary particle size can be obtained, and sufficient hardness may not be imparted to the hard coat layer. Further, if the average primary particle size of the silica fine particles is large, the average secondary particle size of the reactive irregularly shaped silica fine particles tends to be large, and if the average secondary particle size is large, the transparency of the hard coat layer is lowered and the transmittance is reduced. Deterioration and haze increase may occur.
The average secondary particle diameter of the reactive irregularly shaped silica fine particles is preferably in the range of 5 nm to 300 nm, and more preferably in the range of 10 nm to 200 nm. If the average secondary particle size of the reactive irregularly shaped silica fine particles is within the above range, it is easy to impart hardness to the hard coat layer and maintain the transparency of the hard coat layer.

  Here, the average primary particle size of the silica fine particles is determined by measuring the silica fine particles in the curable resin composition by a dynamic light scattering method, and the 50% particle size (d50 median) when the particle size distribution is expressed as a cumulative distribution. Diameter). The average primary particle size can be measured using a Microtrac particle size analyzer or a Nanotrac particle size analyzer manufactured by Nikkiso Co., Ltd. In addition, the average secondary particle size of the reactive irregularly shaped silica fine particles can be determined by the same method as the average primary particle size in the curable resin composition. On the other hand, the average secondary particle size of the reactive irregularly shaped silica fine particles is such that, in the hard coat layer, the cross section of the hard coat layer is observed using an SEM photograph or a TEM photograph, and the observed cured reactive irregularly shaped silica fine particles are 100. It can be obtained as an average value of individual selection.

  Silica fine particles do not exclude the use of particles having pores or porous structures inside the particles, such as hollow particles, but solid particles having no pores or porous structures inside the particles should be used. It is more preferable from the viewpoint of improving the hardness.

  The reactive irregularly shaped silica fine particles are formed by bonding the above-mentioned silica fine particles, preferably 3 to 20, more preferably 3 to 10, by an inorganic chemical bond. When the number of silica fine particles bonded by inorganic chemical bonds is small, it is substantially the same as monodisperse particles, and it is difficult to obtain a hard coat layer excellent in adhesion to the substrate, scratch resistance, and pencil hardness. Moreover, when there are many silica fine particles couple | bonded by the inorganic chemical bond, the transparency of a hard-coat layer will fall, and the deterioration of the transmittance | permeability and the raise of a haze may be caused.

  Examples of inorganic chemical bonds include ionic bonds, metal bonds, coordinate bonds, and covalent bonds. Among them, a bond in which the bonded silica fine particles are not dispersed even when the reactive deformed silica fine particles are added to the polar solvent, specifically, a metal bond, a coordination bond, and a covalent bond is preferable, and a covalent bond is particularly preferable. Examples of the polar solvent include water and lower alcohols such as methanol, ethanol and isopropyl alcohol.

  As the particle state of the reactive deformed silica fine particles, 3 to 20 silica fine particles are bonded by an inorganic chemical bond and aggregated particles (aggregated particles), and 3 to 20 silica fine particles are inorganic. Examples thereof include chain particles bonded by chemical bonds and bonded in a chain. Among these, from the viewpoint of increasing the hardness of the hard coat layer, chain particles are preferable as the particle state of the reactive irregularly shaped silica fine particles. Further, it is preferable that the chain particles are contained in at least a part of the reactive irregular shaped silica fine particles.

  Here, when the reactive irregularly shaped silica fine particles are chain particles, the average number of bonds of the silica fine particles is determined by observing the cross section of the hard coat layer using an SEM photograph or a TEM photograph and observing the cured reactive irregularly shaped silica fine particles. 100 are selected, the silica fine particles contained in each reactive deformed silica fine particle are counted, and the average value can be obtained.

  The method for producing reactive irregularly shaped silica fine particles is not particularly limited as long as the silica fine particles bonded by inorganic bonds are obtained, and conventionally known methods can be appropriately selected and used. For example, it can be obtained by adjusting the concentration or pH of the monodispersed silica fine particle dispersion and performing hydrothermal treatment at a high temperature of 100 ° C. or higher. At this time, if necessary, a binder component can be added to promote the binding of the silica fine particles. Further, ions may be removed by passing the silica fine particle dispersion used through an ion exchange resin. Such ion exchange treatment can promote the binding of silica fine particles. After the hydrothermal treatment, the ion exchange treatment may be performed again.

  The reactive irregular shaped silica fine particles have at least a part of the surface coated with an organic component and have a reactive functional group introduced by the organic component on the surface. Here, the organic component is a component containing carbon. Moreover, as an aspect in which at least a part of the surface is coated with an organic component, for example, a compound containing an organic component such as a silane coupling agent reacts with a hydroxyl group present on the surface of the silica fine particles to cause a part of the surface In addition to the mode in which the organic component is bonded to the surface, or the mode in which the organic component having an isocyanate group is reacted with the hydroxyl group present on the surface of the silica fine particle and the organic component is bonded to a part of the surface, for example, silica Examples include an aspect in which an organic component is attached to a hydroxyl group present on the surface of the fine particles by an interaction such as hydrogen bonding, and an aspect in which silica fine particles are contained in the polymer particles.

At least a part of the surface is coated with an organic component, and a method for preparing reactive deformed silica fine particles having a reactive functional group introduced by the organic component on the surface is a reactive functional group to be introduced into the reactive deformed silica fine particles. Thus, a conventionally known method can be appropriately selected and used. Among these, from the viewpoint of suppressing aggregation of the reactive deformed silica fine particles and improving the hardness of the hard coat layer, any one of the following reactive deformed silica fine particles (i) and (ii) may be appropriately selected and used. preferable.
(I) saturated or unsaturated carboxylic acid, acid anhydride, acid chloride, ester and acid amide corresponding to the carboxylic acid, amino acid, imine, nitrile, isonitrile, epoxy compound, amine, β-dicarbonyl compound, silane, And the modified silica fine particles are dispersed in at least one of water and an organic solvent as a dispersion medium in the presence of one or more surface modification compounds having a molecular weight of 500 or less selected from the group consisting of metal compounds having functional groups. Reactive deformed silica fine particles having a reactive functional group on the surface, obtained by
(Ii) a compound containing a reactive functional group to be introduced into the deformed silica fine particle before coating, a group represented by the following chemical formula (2), and a silanol group or a group that generates a silanol group by hydrolysis, and metal oxide fine particles Reactive deformed silica fine particles having a reactive functional group on the surface, obtained by bonding.
−Q ¹ −C (= Q ² ) −Q ³ − (2)
(In formula (2), Q ¹ represents NH, O or S, Q ² represents O or S, and Q ³ represents NH or a divalent or higher organic group.)
Hereinafter, the reactive irregular-shaped silica fine particle used suitably is demonstrated.

(I) saturated or unsaturated carboxylic acid, acid anhydride, acid chloride, ester and acid amide corresponding to the carboxylic acid, amino acid, imine, nitrile, isonitrile, epoxy compound, amine, β-dicarbonyl compound, silane, And the modified silica fine particles are dispersed in at least one of water and an organic solvent as a dispersion medium in the presence of one or more surface modification compounds having a molecular weight of 500 or less selected from the group consisting of metal compounds having functional groups. Reactive deformed silica fine particles having a reactive functional group on the surface, obtained by
When the reactive irregularly shaped silica fine particles (i) are used, there is an advantage that the strength of the hard coat layer can be improved even if the organic component content is small.

  The surface-modifying compound used for the reactive deformed silica fine particles (i) is a carboxyl group, acid anhydride group, acid chloride group, acid amide group, ester group, imino group, nitrile group, isonitrile group, hydroxyl group, thiol. Groups, epoxy groups, primary, secondary and tertiary amino groups, Si-OH groups, hydrolysable residues of silanes, or C-H acid groups such as β-dicarbonyl compounds It has a functional group capable of chemically bonding with a group present on the surface of the deformed silica fine particle under conditions. The chemical bond here preferably includes a covalent bond, an ionic bond or a coordination bond, but also includes a hydrogen bond. The coordination bond is considered to be complex formation. For example, an acid-base reaction, complex formation or esterification according to Bronsted or Lewis occurs between the functional group of the surface modifying compound and the group on the surface of the deformed silica fine particle. The surface modification compound used for the reactive irregular shaped silica fine particles (i) can be used alone or in combination of two or more.

  The surface-modifying compound is usually added to at least one functional group capable of participating in chemical bonding with the surface group of the irregular-shaped silica fine particle, and after binding to the surface-modifying compound via this functional group, the irregular-shaped silica fine particle is newly added. It has molecular residues that give unique properties. Hereinafter, at least one functional group that can participate in chemical bonding with a group on the surface of the irregular shaped silica fine particle is referred to as a first functional group. The molecular residue or a part thereof is hydrophobic or hydrophilic and, for example, stabilizes, integrates, or activates irregular shaped silica fine particles. For example, the hydrophobic molecular residue includes an alkyl, aryl, alkaryl, aralkyl, or fluorine-containing alkyl group that causes inactivation or repulsion. Examples of the hydrophilic group include a hydroxy group, an alkoxy group, and a polyester group.

  The reactive functional group introduced to the surface so that the reactive irregularly shaped silica fine particles can react with the monomer described later is appropriately selected according to the monomer. As the reactive functional group, a polymerizable unsaturated group is suitably used, preferably a photocurable unsaturated group, and particularly preferably an ionizing radiation curable unsaturated group. Specific examples thereof include ethylenically unsaturated bonds such as (meth) acryloyl group, vinyl group and allyl group, and epoxy group.

  When a reactive functional group capable of reacting with a monomer described later is contained in the molecular residue of the surface modifying compound, the first functional group contained in the surface modifying compound is reacted with the surface of the deformed silica fine particle. By this, it is possible to introduce a reactive functional group capable of reacting with the monomer on the surface of the reactive deformed silica fine particles (i). For example, in addition to the first functional group, a surface modification compound further having a polymerizable unsaturated group is preferable.

  On the other hand, in the molecular residue of the surface modification compound, a second reactive functional group is contained, and the second reactive functional group is used as a foothold for the reactive deformed silica fine particles of (i). A reactive functional group capable of reacting with the monomer may be introduced on the surface. For example, a hydrogen bond-forming group capable of hydrogen bonding such as a hydroxyl group and an oxy group is introduced as the second reactive functional group, and another surface modification compound is added to the hydrogen bond-forming group introduced on the surface of the fine particles. It is preferable to introduce a reactive functional group capable of reacting with the monomer by the reaction of the hydrogen bond forming group. That is, as a surface modification compound, it is preferable to use a compound having a hydrogen bond forming group and a compound having a reactive functional group capable of reacting with a monomer such as a polymerizable unsaturated group and a compound having a hydrogen bond forming group in combination. As mentioned. Specific examples of the hydrogen bond-forming group indicate a functional group such as a hydroxyl group, a carboxyl group, an epoxy group, a glycidyl group, an amide group, or an amide bond. Here, the amide bond indicates that the bond unit contains —NHC (O) or> NC (O) —. Among the hydrogen bond forming groups used in the surface modification compound, a carboxyl group, a hydroxyl group, and an amide group are particularly preferable.

  The surface-modifying compound used in the reactive deformed silica fine particles of (i) above has a molecular weight of 500 or less, more preferably 400, particularly 200. Since it has such a low molecular weight, it is presumed that the surface of the silica fine particles can be rapidly occupied and aggregation of the reactive irregular shaped silica fine particles can be prevented.

  The surface modifying compound used in the reactive deformed silica fine particles (i) is preferably a liquid under the reaction conditions for surface modification, and is preferably soluble or at least emulsifiable in a dispersion medium. Among these, it is preferable that the polymer is dissolved in the dispersion medium and uniformly distributed as discrete molecules or molecular ions in the dispersion medium.

  Saturated or unsaturated carboxylic acids have 1 to 24 carbon atoms, such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, acrylic acid, methacrylic acid, crotonic acid, citric acid, Examples include adipic acid, succinic acid, glutaric acid, oxalic acid, maleic acid, fumaric acid, itaconic acid and stearic acid, and the corresponding acid anhydrides, chlorides, esters and amides such as caprolactam. Further, when an unsaturated carboxylic acid is used, a polymerizable unsaturated group can be introduced.

Examples of preferred amines are those having the following chemical formula:
Q _3-n NH _n
In the above formula, n is 0, 1 or 2. Residue Q is independently alkyl having 1 to 12, especially 1 to 6, particularly preferably 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, i-propyl and butyl, and 6 to 24 Represents aryl, alkaryl or aralkyl having 5 carbon atoms such as phenyl, naphthyl, tolyl and benzyl. Examples of preferred amines include polyalkyleneamines, and specific examples are methylamine, dimethylamine, trimethylamine, ethylamine, aniline, N-methylaniline, diphenylamine, triphenylamine, toluidine, ethylenediamine, and diethylenetriamine. .

Preferred β-dicarbonyl compounds are those having 4 to 12, particularly 5 to 8 carbon atoms, such as diketones such as acetylacetone, 2,3-hexanedione, 3,5-heptanedione, acetoacetic acid, acetoacetic acid. -C acetoacetate such as ethyl ester 1 _-C 4 _- alkyl esters, diacetyl and acetonyl acetone.
Examples of amino acids include β-alanine, glycine, valine, aminocaproic acid, leucine and isoleucine.

  Preferred silanes are hydrolyzable organosilanes having at least one hydrolyzable group or hydroxy group and at least one non-hydrolyzable residue. Here, examples of the hydrolyzable group include a halogen, an alkoxy group, and an acyloxy group. As the non-hydrolyzable residue, a non-hydrolyzable residue having a reactive functional group or not having a reactive functional group is used. Silanes having at least partially organic residues substituted with fluorine may also be used.

As the silane used is not particularly limited, for _{example, CH 2 = CHSi (OOCCH 3} ) 3, CH 2 = CHSiCl 3, CH 2 = CHSi (OC 2 H 5) 3, CH 2 = CHSi (OC 2 H _{4 OCH 3) 3, CH 2} = CH-CH 2 -Si (OC 2 H 5) 3, CH 2 = CH-CH 2 -Si (OOCCH 3) 3, γ- glycidyloxypropyltrimethoxysilane (GPTS), γ-glycidyloxypropyldimethylchlorosilane, 3-aminopropyltrimethoxysilane (APTS), 3-aminopropyltriethoxysilane (APTES), N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- [ N '-(2'-aminoethyl) -2-aminoethyl] -3-aminopropyltrimethoxy Sisilane, hydroxymethyltrimethoxysilane, 2- [methoxy (polyethyleneoxy) propyl] trimethoxysilane, bis- (hydroxyethyl) -3-aminopropyltriethoxysilane, N-hydroxyethyl-N-methylaminopropyltriethoxysilane , 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, and the like.

  The silane coupling agent is not particularly limited and may include known ones, such as KBM-502, KBM-503, KBE-502, KBE-503 manufactured by Shin-Etsu Chemical Co., Ltd. be able to.

Examples of the metal compound having a functional group include a metal compound of metal M from at least one of the first group III to V and the second group II to IV of the periodic table. Specific examples include zirconium and titanium alkoxides represented by the following chemical formula.
M (OR) ₄
In the above formula, M is Ti or Zr. A part of the OR group is substituted with a complexing agent such as a β-dicarbonyl compound or a monocarboxylic acid. When a compound having a polymerizable unsaturated group such as methacrylic acid is used as a complexing agent, a polymerizable unsaturated group can be introduced.

As the dispersion medium, at least one of water and an organic solvent is preferably used. A particularly preferred dispersion medium is distilled pure water. As the organic solvent, polar, nonpolar and aprotic solvents are preferred. Examples thereof include alcohols such as aliphatic alcohols having 1 to 6 carbon atoms such as methanol, ethanol, n- and i-propanol and butanol, ketones such as methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, acetone and butanone, acetic acid Esters such as ethyl; ethers such as diethyl ether, tetrahydrofuran and tetrahydropyran; amides such as dimethylacetamide and dimethylformamide; sulfoxides and sulfones such as sulfolane and dimethyl sulfoxide; and optionally, such as pentane, hexane and cyclohexane Aliphatic hydrocarbons which may be halogenated are mentioned. These dispersion media can be used as a mixture.
The dispersion medium preferably has a boiling point that can be easily removed by distillation, optionally under reduced pressure, and a solvent having a boiling point of 200 ° C. or lower, particularly 150 ° C. or lower is preferable.

  In the preparation of the reactive deformed silica fine particles (i), the concentration of the dispersion medium is usually within the range of 40% by mass to 90% by mass, preferably within the range of 50% by mass to 80% by mass, particularly 55% by mass to 75%. It is in the range of mass%. The rest of the dispersion is composed of untreated silica fine particles and the surface modifying compound. Here, the weight ratio of silica fine particles: surface modification compound is preferably 100: 1 to 4: 1, more preferably 50: 1 to 8: 1, and particularly preferably 25: 1 to 10: 1.

  The reactive irregularly shaped silica fine particles (i) are preferably prepared in a temperature range of about 20 ° C. to the boiling point of the dispersion medium. Particularly preferably, the dispersion temperature is 50 ° C to 100 ° C. The dispersion time depends in particular on the type of material used, but is generally from a few minutes to a few hours, for example from 1 to 24 hours.

(Ii) a reactive functional group to be introduced into the deformed silica fine particle before coating, a group represented by the following chemical formula (2), and a compound containing a silanol group or a group that generates a silanol group by hydrolysis; Reactive deformed silica fine particles having a reactive functional group on the surface, obtained by bonding with metal oxide fine particles.
−Q ¹ −C (= Q ² ) −Q ³ − (2)
(In formula (2), Q ¹ represents NH, O or S, Q ² represents O or S, and Q ³ represents NH or a divalent or higher organic group.)
When the reactive irregularly shaped silica fine particles (ii) are used, there are advantages that the amount of organic components is increased, and the dispersibility and the strength of the hard coat layer are further increased.

First, a compound containing a reactive functional group to be introduced into the silica fine particles before coating, a group represented by the above chemical formula (2), and a silanol group or a group that generates a silanol group by hydrolysis will be described. Hereinafter, the compound may be referred to as a reactive functional group-modified hydrolyzable silane.
In the reactive functional group-modified hydrolyzable silane, the reactive functional group to be introduced into the silica fine particles is not particularly limited as long as it is appropriately selected so as to be capable of reacting with a monomer described later. Suitable for introducing polymerizable unsaturated groups as described above.

In the reactive functional group-modified hydrolyzable silane, the [—Q ¹ —C (═Q ² ) —] moiety of the group represented by the chemical formula (2) is specifically [—O—C (═O )-], [-OC (= S)-], [-SC (= O)-], [-NH-C (= O)-], [-NH-C (= S)- ] And [-S-C (= S)-]. These groups can be used alone or in combination of two or more. Among them, from the viewpoint of thermal stability, at least of a [—O—C (═O) —] group, a [—O—C (═S) —] group, and a [—S—C (═O) —] group It is preferable to use one type in combination. The group [—Q ¹ —C (= Q ² ) —Q ³ —] represented by the above formula (2) generates an appropriate cohesive force due to hydrogen bonding between molecules, and has excellent mechanical properties when formed into a cured product. It is considered that properties such as strength, adhesion to the substrate, and heat resistance can be imparted.

  Examples of the group that generates a silanol group by hydrolysis include a group having an alkoxy group, an aryloxy group, an acetoxy group, an amino group, a halogen atom, etc. on the silicon atom. An oxysilyl group is preferred. A silanol group or a group that generates a silanol group by hydrolysis can be combined with the metal oxide fine particles by a condensation reaction or a condensation reaction that occurs following hydrolysis.

  Preferable specific examples of the reactive functional group-modified hydrolyzable silane include compounds represented by the following chemical formulas (3) and (4), and the compound represented by the following chemical formula (4) is from the point of hardness. More preferably used.

In the above formulas (3) and (4), R ^a and R ^b may be the same or different, but are a hydrogen atom or a C ₁ to C ₈ alkyl group or aryl group, for example, methyl, ethyl, propyl , Butyl, octyl, phenyl, xylyl group and the like. Here, m is 1, 2 or 3.
Examples of the group represented by [(R ^a O) _m R ^b _3-m Si—] include a trimethoxysilyl group, a triethoxysilyl group, a triphenoxysilyl group, a methyldimethoxysilyl group, and a dimethylmethoxysilyl group. Can be mentioned. Of these groups, a trimethoxysilyl group or a triethoxysilyl group is preferable.

In formulas (3) and (4), R ^c is a divalent organic group having a C ₁ to C ₁₂ aliphatic or aromatic structure and may contain a chain, branched or cyclic structure. . Examples of such an organic group include methylene, ethylene, propylene, butylene, hexamethylene, cyclohexylene, phenylene, xylylene, and dodecamethylene. Among these, preferred examples are methylene, propylene, cyclohexylene, phenylene and the like.

In the formula (3), R ^d is a divalent organic group, and is usually selected from divalent organic groups having a molecular weight of 14 to 10,000, preferably a molecular weight of 76 to 500. For example, chain polyalkylene groups such as hexamethylene, octamethylene, dodecamethylene; alicyclic or polycyclic divalent organic groups such as cyclohexylene and norbornylene; divalent groups such as phenylene, naphthylene, biphenylene and polyphenylene An aromatic group; and these alkyl group-substituted and aryl group-substituted products. Further, these divalent organic groups may contain an atomic group containing an element other than carbon and hydrogen atoms, and include a polyether bond, a polyester bond, a polyamide bond, a polycarbonate bond, and a group represented by the above formula (2). Can also be included.

In the formulas (3) and (4), R ^e is an (n + 1) valent organic group, preferably selected from a chain, branched or cyclic saturated hydrocarbon group and unsaturated hydrocarbon group.

  In the formulas (3) and (4), Y ′ represents a monovalent organic group having a reactive functional group. The reactive functional group itself as described above may be used. For example, when the reactive functional group is selected from a polymerizable unsaturated group, (meth) acryloyl (oxy) group, vinyl (oxy) group, propenyl (oxy) group, butadienyl (oxy) group, styryl (oxy) group, Examples include ethynyl (oxy) group, cinnamoyl (oxy) group, maleate group, (meth) acrylamide group and the like. N is preferably a positive integer of 1 to 20, more preferably 1 to 10, particularly preferably 1 to 5.

  For the synthesis of the reactive functional group-modified hydrolyzable silane, for example, the method described in JP-A-9-100111 can be used. That is, for example, when it is desired to introduce a polymerizable unsaturated group, (A) an addition reaction between a mercaptoalkoxysilane, a polyisocyanate compound, and an active hydrogen group-containing polymerizable unsaturated compound capable of reacting with an isocyanate group is performed. it can. Moreover, it can carry out by (B) direct reaction with the compound which has an alkoxy silyl group and an isocyanate group in a molecule | numerator, and an active hydrogen group containing polymerizable unsaturated compound. Furthermore, it can also be directly synthesized by addition reaction of (C) a compound having a polymerizable unsaturated group and an isocyanate group in the molecule with mercaptoalkoxysilane or aminosilane.

  In the production of the reactive deformed silica fine particles of (ii), after separately hydrolyzing the reactive functional group-modified hydrolyzable silane, this is mixed with the deformed silica fine particles, followed by heating and stirring operation, Alternatively, a method of hydrolyzing a reactive functional group-modified hydrolyzable silane in the presence of deformed silica fine particles, and other components such as polyunsaturated organic compounds, monounsaturated organic compounds, radiation polymerization initiators, etc. Although the method of performing the surface treatment of the deformed silica fine particles in the presence of can be selected, a method of hydrolyzing the reactive functional group-modified hydrolyzable silane in the presence of the deformed silica fine particles is preferable. When the reactive deformed silica fine particles (ii) are produced, the temperature is usually 20 ° C. or higher and 150 ° C. or lower, and the treatment time is in the range of 5 minutes to 24 hours.

  In order to accelerate the hydrolysis reaction, an acid, salt or base may be added as a catalyst. Preferable examples of the acid include organic acids and unsaturated organic acids; examples of the base include tertiary amines or quaternary ammonium hydroxides. The addition amount of these acid or base catalysts is within the range of 0.001% by mass to 1.0% by mass, preferably 0.01% by mass to 0.1% by mass with respect to the reactive functional group-modified hydrolyzable silane. Within range.

  As the reactive irregularly shaped silica fine particles, powdery fine particles not containing a dispersion medium may be used. However, it is preferable to use a fine particle in a solvent dispersion sol because the dispersion step can be omitted and the productivity is high.

  On the other hand, when the reactive silica fine particles are spherical reactive silica fine particles, a reactive functional group is formed on the surface of the silica fine particles having an average primary particle diameter in the range of 1 nm to 100 nm, more preferably in the range of 5 nm to 80 nm. What has is preferable. Since the silica fine particles used for the spherical reactive silica fine particles and the method for introducing the reactive functional group can be the same as those of the reactive deformed silica fine particles, description thereof is omitted here.

The content of the inorganic oxide fine particles is preferably in the range of 40% by mass to 70% by mass with respect to the total solid content of the curable resin composition, and is in the range of 50% by mass to 60% by mass. Is more preferable. When the content is small, there is a possibility that sufficient hardness cannot be imparted to the hard coat layer. When the content is large, the filling rate is excessively increased, the adhesion between the inorganic oxide fine particles and the monomer is deteriorated, and the hardness of the hard coat layer may be lowered.
Here, solid content means things other than a solvent among the components contained in curable resin composition.

(C) Polymer In the present invention, the polymer is a component that imparts flexibility to the hard coat layer.
Examples of the polymer include urethane polymers and acrylic polymers.
Among them, it is preferable to use an acrylic polymer. This is because processability can be improved while maintaining the hardness of the hard coat layer.

  As the urethane polymer, known components are used as components of a general hard coat layer, and examples thereof include those described in JP 2010-120182 and JP 2012-148484 PR.

The acrylic polymer has a weight average molecular weight in the range of 30,000 to 80,000 and 60,000 to 80,000 from the viewpoint of imparting flexibility to the hard coat layer and preventing cracks during processing. It is preferable to be within the range.
Here, the weight average molecular weight refers to a weight average molecular weight which is a polystyrene conversion value measured by gel permeation chromatography.

The acrylic polymer has an acrylic equivalent in the range of 200 to 1,000, preferably in the range of 200 to 400.
Here, the acrylic equivalent indicates a value obtained by dividing the weight average molecular weight of the acrylic polymer by the number of (meth) acrylic groups in one molecule.

The acrylic polymer is not particularly limited as long as it satisfies the above weight average molecular weight and acrylic equivalent, but it is a polymer of glycerol (meth) acrylate or a compound of a compound obtained by addition polymerization of (meth) acrylic acid to glycidyl methacrylate. It is preferably a coalescence.
Specifically, a polymer of an acrylic monomer represented by the following chemical formula (5) or (6) is preferably used.

In the above formula (5), R ^{1 to} R ³ are each independently an acrylate group, a methacrylate group or a hydrogen atom, and one or more of R ^{1 to} R ³ are an acrylate group or a methacrylate group. That is, the glycerol (meth) acrylate represented by the above formula (5) may be monofunctional, bifunctional, or trifunctional.
In the above formula (6), R is an acrylic acid group or a methacrylic acid group.

As such an acrylic polymer, for example, BL-2002 manufactured by Seiko PMC Co., Ltd. may be mentioned.
Moreover, as an acrylic polymer, you may use individually by 1 type, and may mix and use 2 or more types suitably.

The polymer content is preferably in the range of 3% by mass to 20% by mass, more preferably 5% by mass to 10% by mass, and more preferably 6% by mass with respect to the total solid content of the curable resin composition. More preferably, it is in the range of% to 8% by mass. If content of a polymer is in the said range, the workability of the front substrate for touchscreens can be improved.
The polymer content is preferably in the range of 5 to 80 parts by weight, more preferably in the range of 20 to 40 parts by weight, based on 100 parts by weight of the monomer described below. More preferably, it is in the range of 10 to 30 parts by weight.

(D) Monomer In this invention, a monomer is a component used as the matrix of a hard-coat layer.
The monomer usually has a reactive functional group. Monomers crosslink between monomers when cured. In addition, when the reactive irregularly shaped silica fine particles are contained, the reactive functional group of the monomer has cross-linking reactivity with the reactive functional group of the reactive irregularly shaped silica fine particles, so that the monomer crosslinks with the reactive irregularly shaped silica fine particles, A structure is formed which further enhances the hardness and scratch resistance of the hard coat layer. As the reactive functional group, a polymerizable unsaturated group is suitably used, preferably a photocurable unsaturated group, and particularly preferably an ionizing radiation curable unsaturated group. Specific examples include ethylenically unsaturated bonds such as (meth) acryloyl groups, vinyl groups, allyl groups, and epoxy groups. The reactive functional group of the monomer may be the same as or different from the reactive functional group of the reactive deformed silica fine particle.

  As the monomer, a curable organic resin is preferable, and a translucent material that transmits light when it is used as a coating film is preferable. An ionizing radiation curable resin that is a resin that is cured by ionizing radiation represented by ultraviolet rays or electron beams, Other known curable resins and the like may be appropriately employed according to required performance. Examples of the ionizing radiation curable resin include acrylate-based, oxetane-based, and silicone-based resins. As the monomer, one type or two or more types of monomers can be used.

The monomer preferably has three or more reactive functional groups from the viewpoint of increasing the crosslinking density. Examples of the polyfunctional monomer having three or more reactive functional groups include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and dipentaerythritol penta (meth) acrylate. , Trimethylolpropane tri (meth) acrylate, trimethylolpropane hexa (meth) acrylate, and modified products thereof. In addition, as a modified body, an ethylene oxide modified body, a propylene oxide modified body, a caprolactone modified body, an isocyanuric acid modified body, etc. are mentioned.
Among them, as the polyfunctional monomer, pentaerythritol triacrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, and dipentaerythritol pentaacrylate are preferably used, and dipentaerythritol hexaacrylate, penta Erythritol tetraacrylate and dipentaerythritol pentaacrylate are particularly preferably used.

  The content of the monomer is preferably in the range of 25% by mass to 44% by mass and more preferably in the range of 30% by mass to 40% by mass with respect to the total solid content of the curable resin composition. . When the content is small, there is a possibility that sufficient hardness cannot be imparted to the hard coat layer. Moreover, when there is much content, the hardness of a hard-coat layer will go up too much, and content of a polymer may become relatively small, and there exists a possibility of reducing the workability of the front substrate for touchscreens.

(E) Polymerization initiator The polymerization initiator is decomposed by at least one of light and heat to generate radicals or cations to advance radical polymerization and cationic polymerization.
As the polymerization initiator, radical polymerization initiators, cationic polymerization initiators, radicals and cationic polymerization initiators can be appropriately selected and used.

  The radical polymerization initiator only needs to be capable of releasing a substance that initiates radical polymerization by at least one of light and heat. For example, examples of the photo radical polymerization initiator include imidazole derivatives, bisimidazole derivatives, N-aryl glycine derivatives, organic azide compounds, titanocenes, aluminate complexes, organic peroxides, N-alkoxypyridinium salts, thioxanthone derivatives, and the like. It is done. Specific examples include those described in JP 2010-102123 A and JP 2010-120182 A.

Moreover, the cationic polymerization initiator should just be able to discharge | release the substance which starts cationic polymerization by at least any one of light and a heat | fever. Examples of the cationic polymerization initiator include sulfonic acid ester, imide sulfonate, dialkyl-4-hydroxysulfonium salt, arylsulfonic acid-p-nitrobenzyl ester, silanol-aluminum complex, (η ⁶ -benzene) (η ⁵ -cyclopentadidiene). Enil) iron (II) and the like. Specific examples include those described in JP 2010-102123 A and JP 2010-120182 A.

  Examples of radical polymerization initiators and cationic polymerization initiators that can be used include aromatic iodonium salts, aromatic sulfonium salts, aromatic diazonium salts, aromatic phosphonium salts, triazine compounds, and iron arene complexes. Specific examples include those described in JP 2010-102123 A and JP 2010-120182 A.

  Among them, the polymerization initiator preferably has a relatively low absorption rate in the visible light region. This is because if the absorptance in the visible light region is high, the light transmittance of the front substrate for touch panel may be lowered.

  The content of the polymerization initiator is preferably in the range of 2% by mass to 5% by mass with respect to the total solid content of the curable resin composition, and preferably in the range of 2% by mass to 2.5% by mass. It is more preferable. If the content is small, the polymerization reaction of monomers or the like does not proceed sufficiently, and there is a possibility that sufficient hardness cannot be imparted to the hard coat layer. Moreover, when there is much content, polymerization reaction, such as a monomer, advances rapidly, and there exists a possibility that workability | operativity may fall or it may become a non-uniform hardened | cured material.

(F) Solvent The curable resin composition usually contains a solvent. Although the kind of solvent is not specifically limited, For example, methyl isobutyl ketone, propylene glycol monomethyl ether, normal propanol, isopropanol, normal butanol, sec-butanol, isobutanol, tert-butanol etc. are mentioned.

(G) Other components The curable resin composition used for this invention may contain the antistatic agent, the glare-proof agent, various sensitizers, etc. as needed.

(H) Curable resin composition The curable resin composition is prepared by mixing and dispersing dispersion of reactive irregularly shaped silica fine particles, acrylic polymer, monomer, polymerization initiator and the like in a solvent according to a general preparation method. Can do. For mixing and dispersing, a paint shaker or a bead mill can be used.

(2) Hard Coat Layer The dynamic friction coefficient of the surface of the hard coat layer used in the present invention is not particularly limited as long as desired slipperiness can be exhibited. The said dynamic friction coefficient can show favorable slipperiness, so that the value is small. The coefficient of dynamic friction on the surface of the hard coat layer is, for example, preferably 0.200 or less, and more preferably 0.100 or less. This is because if the dynamic friction coefficient is too large, it may be difficult to perform a good touch operation on the surface of the hard coat layer.
The dynamic friction coefficient can be measured by a method according to JIS K7125. For example, a dynamic friction tester HEIDON Type HHS2000 manufactured by Shinto Kagaku Co., Ltd. is used, a stainless hard ball having a diameter of 10 mm, a load of 200 g, and a speed. The dynamic friction coefficient can be measured at 5 mm / sec.

The wettability of the hard coat layer is appropriately determined according to the components used in the curable resin composition, and is not particularly limited, but the contact angle of water droplets on the hard coat layer is 90 ° or more. Preferably, it is 100 ° or more, and more preferably 110 ° or more. This is because the hard coat layer can exhibit good antifouling properties. On the other hand, the contact angle of the water droplet is usually 120 ° or less.
In addition, the contact angle of a water droplet can be calculated | required by measuring using a contact angle measuring device (Kyowa Interface Science Co., Ltd. product CA-Z type | mold) 30 seconds after dripping a water droplet from a microsyringe.

The hard coat layer is light transmissive. Specifically, the transmittance of the hard coat layer in the visible light region is preferably 80% or more, and more preferably 90% or more. It is because it can be set as the hard-coat layer excellent in the light transmittance because the said transmittance | permeability is the said range.
Here, the transmittance of the hard coat layer is the total light transmittance measured by the method defined in JIS K 7105.

The haze value of the hard coat layer is appropriately determined according to the type of inorganic oxide fine particles and the like, and is not particularly limited. For example, it is 1.0 or less, particularly 0.8 or less, particularly 0.5 or less. preferable. It is because it can be set as the hard-coat layer with favorable light transmittance because haze value is the said range.
In addition, a haze value can be measured by the method based on JIS-K-7136, for example, can be measured with the direct reading haze meter by Toyo Seiki Seisakusho Co., Ltd. using a semi-integral sphere.

  The hardness of the hard coat layer can be evaluated by a pencil hardness test (4.9 N load) defined by JIS K5600-5-4 (1999). The pencil hardness of the hard coat layer is preferably 6H or more, more preferably 7H or more, and particularly preferably 9H or more.

  The thickness of the hard coat layer is not particularly limited as long as it can have desired slipperiness, hardness, scratch resistance, and the like, and can be, for example, about 5 μm to 40 μm, and more preferably 10 μm to 30 μm. It is preferable to be in the range, particularly in the range of 18 to 22 μm. This is because if the hard coat layer is thin, sufficient hardness cannot be exhibited, and if it is thick, cracks and warpage may occur.

The method for forming the hard coat layer is not particularly limited as long as the hard coat layer can be formed using the curable resin composition, and the curable resin composition is applied onto the substrate, A method of curing the coating film can be used.
The coating method of the curable resin composition is not particularly limited as long as the curable resin composition can be uniformly coated on the substrate, and is not limited to spin coating, dipping, spraying, slide coating. Various methods such as a method, a bar coat method, a roll coater method, a meniscus coater method, a flexographic printing method, a screen printing method, and a speed coater method can be used. Moreover, it is preferable to adjust as the coating amount of the curable resin composition on a board | substrate so that the hard-coat layer of a desired film thickness may be obtained.
Examples of the method for drying the coating film include reduced-pressure drying, heat drying, and combinations thereof. When drying at normal pressure, it is preferable to dry in a temperature range in which the substrate does not deteriorate. For example, it is preferable to dry within a range of 30 ° C to 110 ° C.

As a method for curing the coating film, at least one of light irradiation and heating can be used.
For light irradiation, ultraviolet rays, visible light, electron beams, ionizing radiation, etc. are mainly used, and among these, ultraviolet rays are preferably used. In the case of ultraviolet curing, ultraviolet rays emitted from light such as an ultra high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp are used. The amount of irradiation with the energy radiation source of accumulative exposure at an ultraviolet wavelength of 365 nm, is preferably in the range of, for example, ^{50mJ / cm 2 ~5000mJ / cm 2} .
Moreover, when heating, it is preferable to heat in the temperature range in which a board | substrate does not deteriorate, for example, it is preferable to heat within the range of 40 to 120 degreeC. Moreover, you may react by leaving it to stand for 24 hours or more at room temperature of about 25 degreeC.

2. Substrate The substrate used in the present invention is not particularly limited as long as it has optical transparency and satisfies physical properties that can be used as a substrate for a front substrate for a touch panel. Usually, a substrate used for a front substrate for a touch panel may be transparent, translucent, colorless, or colored, but is required to have light transmittance.

  Examples of the substrate material include acrylate polymers, polycarbonates, polyesters, cellulose acylates, and cycloolefin polymers. Specific examples of the acrylate polymer include methyl poly (meth) acrylate, poly (meth) ethyl acrylate, methyl (meth) acrylate-butyl (meth) acrylate, and the like. Specific examples of the polycarbonate include aromatic polycarbonates based on bisphenols such as bisphenol A, and aliphatic polycarbonates such as diethylene glycol bisallyl carbonate. Specific examples of the polyester include polyethylene terephthalate and polyethylene naphthalate. Specific examples of cellulose acylate include cellulose triacetate, cellulose diacetate, and cellulose acetate butyrate. Specific examples of the cycloolefin polymer include norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymer resins, and the like.

  The substrate may be a single layer or a laminate of a plurality of layers. In the case of a single layer, the substrate material is preferably an acrylate polymer, more preferably polymethyl methacrylate. This is because the transparency is high. On the other hand, in the case of a plurality of layers, the substrate has a plurality of resin layers. The number of resin layers may be two or more, preferably in the range of 3 to 5 layers, and more preferably 3 layers.

  When the substrate has three or more resin layers, the two outermost layers are the outermost resin layers, and the layers positioned inside the two outermost resin layers are the inner resin layers. As shown in FIG. 2, for example, when the substrate 1 has three resin layers 1a to 1c, the two outermost resin layers 1b and 1c are the two outermost resin layers 1b and 1c, The layer located inside 1c is referred to as an inner resin layer 1a. The inner resin layer 1a may be a single layer or a plurality of layers.

  When the substrate has three or more resin layers, the pencil hardness of the two outermost resin layers located on both sides of the substrate is preferably higher than the pencil hardness of the inner resin layer. By increasing the hardness of the outermost resin layer, it becomes easier to form a front substrate for a touch panel with high hardness, and by reducing the hardness of the inner resin layer, the stress caused by the difference in coefficient of thermal expansion can be relieved, that is, This is because the inner resin layer becomes a cushion layer, and impact resistance such as falling ball test resistance is improved. The difference in hardness between the outermost resin layer and the inner resin layer is preferably two or more steps, more preferably three or more steps, on the basis of pencil hardness. For example, the pencil hardness of the outermost resin layer is preferably HB or higher, and more preferably H or higher and 5H or lower. The pencil hardness of the inner resin layer is preferably H or less, for example, and more preferably 3B or more and HB or less.

When the substrate has a plurality of resin layers, the pencil hardness of the substrate is preferably 2H or more, and more preferably 3H or more. This is because the hardness of the front substrate for touch panel can be further improved. The pencil hardness of the substrate is preferably high, but is usually 4H or less.
On the other hand, even when the substrate is a single layer, the pencil hardness of the substrate is preferably 2H or more.

  Moreover, as illustrated in FIG. 2, when the substrate 1 has three resin layers 1a to 1c, the inner resin layer 1a is polycarbonate, and the two outermost resin layers 1b and 1c are acrylate polymers. Is preferred. This is because the impact resistance is improved. In this case, the thickness of one outermost resin layer is preferably in the range of 60 μm to 110 μm.

  The substrate preferably transmits more light. The total light transmittance in the visible light region is preferably 80% or more, and more preferably 90% or more. The total light transmittance is a value measured by a method defined in JIS K 7105.

Although the thickness of a board | substrate is not specifically limited, It is preferable that it is 0.3 mm or more, and it is more preferable that it exists in the range of 0.3 mm-5 mm. It is because sufficient impact resistance can be maintained within the above range.
Further, the substrate may be subjected to surface treatment such as saponification treatment, glow discharge treatment, corona discharge treatment, ultraviolet treatment, flame treatment and the like.

3. Other Configurations The front substrate for a touch panel of the present invention may have a substrate and a hard coat layer, but may further have another layer depending on the use of the front substrate for touch panel. Examples of other layers include a primer layer, an antistatic layer, an antiglare layer, and a low refractive index layer.

In the present invention, as illustrated in FIG. 3, the second hard coat layer 3 may be formed on the surface of the substrate 1 opposite to the surface on which the hard coat layer 2 is formed. By forming the second hard coat layer, the hardness of the front substrate for touch panel can be further improved.
The curable resin composition used for the second hard coat layer may be the same as or different from the curable resin composition used for the hard coat layer.

4). Front substrate for touch panel The front substrate for touch panel of the present invention is disposed on the outermost surface of the touch panel. Moreover, the front substrate for touch panels of this invention can be used suitably for the touch panel operated by making a finger | toe contact directly.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  The following examples illustrate the present invention in more detail.

[Example 1]
(Preparation)
As a substrate, a laminate in which polymethyl methacrylate (PMMA), polycarbonate (PC), and polymethyl methacrylate (PMMA) were laminated in this order was prepared. The laminate had an overall thickness of 1.0 mm, a PMMA thickness of 100 μm, and a pencil hardness of 3H.
As reactive irregularly shaped silica fine particles, 3 to 10 silica fine particles having an average primary particle size of 55 nm are bonded by an inorganic chemical bond and have an average secondary particle size of 100 to 300 nm, and have a photocurable unsaturated group as a reactive functional group. Using reactive irregularly shaped silica fine particles, a dispersion of propylene glycol-1-methyl ether acetate (PGMEA) solvent having a solid content concentration of 40.0% by mass was prepared.
Pentaerythritol triacrylate (PETA) was prepared as a monomer. As a polymerization initiator, Irgacure 184 manufactured by Ciba Japan Co., Ltd. was prepared.
Fluorine silicon surfactant X-71-1203M manufactured by Shin-Etsu Chemical Co., Ltd. was prepared as the fluorine silicon surfactant. Propylene glycol-1-methyl ether acetate (PGMEA) was prepared as a solvent.
As the polymer, BL-2002 manufactured by Seiko PMC Co., Ltd., which is an acrylic polymer having a weight average molecular weight of 70,000 and an acrylic equivalent of 265, was used. The composition of BL-2002 manufactured by Seiko PMC Co., Ltd. is 30-40 parts by weight of acrylic resin, 60-70 parts by weight of methyl ethyl ketone, less than 1 part by weight of acetic acid, 2,6-di-tert-butyl-4-cresol. Less than 1 part by weight.

(Preparation of curable resin composition)
A curable resin composition was prepared with the following composition.
Reactive silica fine particle dispersion: 52.5 parts by weight (solid content concentration 40% by mass)
Monomer: 15.0 parts by weight Polymer: 8.60 parts by weight Polymerization initiator: 0.905 parts by weight Fluorosilicone surfactant: 0.190 parts by weight Solvent: 22.8 parts by weight

(Formation of hard coat layer)
A curable resin composition is applied to one side of the substrate by a spin coating method, dried on a hot plate at a temperature of 80 ° C. for 180 seconds, the solvent in the coating film is evaporated, and ultraviolet light is accumulated to 3000 mJ / cm ² . The hard coat layer having a film thickness of 20 μm was formed by curing the coating film by irradiation. The integrated exposure amount was calculated using a wavelength of 365 nm.

[Comparative Example 1]
As a comparative example of the following physical property evaluation, RGW310 manufactured by Nasaka Vacuum Industry Co., Ltd. was prepared. RGW310 uses a three-layer product (C101 manufactured by Sumitomo Chemical Co., Ltd.) in which PMMA, PC, and PMMA are laminated in this order as the base material. The curable resin composition used for the hard coat layer is made of silicon as the surfactant. Surfactant, spherical silica having an average primary particle diameter of 15 nm as inorganic oxide fine particles (about 65% by mass), pentaerythritol polyfunctional acrylate as a monomer, dicyclohexylmethane diisocyanate (hydrogenated MDI) and isophorone diisocyanate (IPDI) as a polymer, It contained Irgacure 184 as a photopolymerization initiator and ε-caprolactone as another component.

[Comparative Example 2]
As a comparative example for the following physical property evaluation, RGW200 manufactured by Nasaka Vacuum Industry Co., Ltd. was prepared. RGW200 uses a PMMA single layer plate as a base material, and the curable resin composition used for the hard coat layer has a silicon-based surfactant as a surfactant and an average primary particle size of 15 nm as inorganic oxide fine particles. Spherical silica (about 65% by mass), pentaerythritol polyfunctional acrylate as monomer, dicyclohexylmethane diisocyanate (hydrogenated MDI) and isophorone diisocyanate (IPDI) as polymer, Irgacure 184 as photopolymerization initiator, and ε-caprolactone as other components Contained.

[Comparative Example 3]
As a comparative example for the following physical property evaluation, a PMMA substrate (Delaglass A999 manufactured by Asahi Kasei Technoplus Co., Ltd.) having a thickness of 1.0 mm was prepared.

[Evaluation 1]
(Dynamic friction coefficient)
About the hard coat layer of the front substrate for touch panels, the dynamic friction coefficient was measured with a dynamic friction tester HEIDON Type HHS2000 manufactured by Shinto Kagaku Co., Ltd. using a stainless hard ball having a diameter of 10 mm at a load of 200 g and a speed of 5 mm / sec.

(Fluorine content and silicon content)
Using X-ray photoelectron spectroscopy (XPS), fluorine (F) content (%) and silicon (Si) content (in the range from the outermost surface of the hard coat layer to 5 nm in the thickness direction ( %) Was measured as follows.
As a measuring device, ESCALAB 220i-XL (XPS device manufactured by Thermo Fisher Scientific) was used. Monochromated Al Kα (monochromic X-ray, hν = 1486.6 eV) was used as incident X-ray. X-ray output was 10 kV · 18 mA (180 W). A Large Area XL (magnetic lens) was used as the lens. Set the aperture opening to F. O. V. = Open, A.I. A. = Open, the measurement region was 700 μmφ, and the photoelectron capture angle was 90 degrees (the input lens was present on the sample normal). Further, using a neutralization auxiliary mask, neutralization was performed with an electron neutralizing gun at +4 (V) · 0.08 (mA).
The fluorine content is the ratio of the number of fluorine to the total number of oxygen, carbon, fluorine, and silicon (unit: atomic%) contained in the hard coat layer. The silicon content is a ratio of the number of silicon to the total number of oxygen, carbon, fluorine, and silicon (unit: atomic%) contained in the hard coat layer.

(Pencil hardness test)
The obtained front substrate for a touch panel is conditioned for 2 hours under conditions of a temperature of 25 ° C. and a relative humidity of 60%, and then using a test pencil specified by JIS-S-6006, JIS K5600-5-4 (1999). The pencil hardness test (4.9 N load) specified in Section 1 was performed, and the highest pencil hardness without scratches was evaluated.

(Mandrel test)
In accordance with the mandrel test described in JIS-K5600-5-1 (a test in which a sample is wound around a metal cylinder), the hard coat layer is wound around the cylinder in the length direction of the front substrate for the touch panel, and cracks occur. The minimum diameter of the bar where no occurred was evaluated. For example, when a crack was generated in a cylinder having a diameter of 150 mm and no crack was generated in a cylinder having a diameter of 160 mm, the thickness was set to 160 mm.
Here, as a result of examining the workability of the front substrate for touch panel by the present inventors, there is a correlation between the mandrel test and the workability, and when the bendability by the mandrel test is good, punching, router processing, cutting Workability in processing and the like was good.

[Comparative Example 4]
As a surfactant used in the curable resin composition, instead of the fluorine silicon surfactant X-71-1203M manufactured by Shin-Etsu Chemical Co., Ltd., the fluorine surfactant Megafac MCF350-5 manufactured by DIC Corporation. A full-surface substrate for a touch panel was prepared in the same manner as in Example 1 except that was used.

[Comparative Example 5]
As a surfactant used in the curable resin composition, a silicon surfactant X22-163A manufactured by Shin-Etsu Chemical Co., Ltd. is used in place of the fluorine silicon surfactant X-71-1203M manufactured by Shin-Etsu Chemical Co., Ltd. A touch panel full board was prepared in the same manner as in Example 1 except that.

[Evaluation 2]
In the same manner as in Example 1, the dynamic friction coefficient on the surface of the hard coat layer of the entire touch panel substrate for Comparative Example 4 and Comparative Example 5 was measured.

  As shown in Table 1 and Table 2, it was confirmed that the lubricity of the hard coat layer was improved by adding a fluorosilicone surfactant.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2 ... Hard-coat layer 10 ... Front board for touchscreens

Claims (1)

A front substrate for a touch panel having a substrate and a hard coat layer formed on the substrate,
The front substrate for a touch panel, wherein the hard coat layer contains a fluorosilicone surfactant.

Images