KR102215669B1 - Hard coated laminate and method for producing same - Google Patents

Abstract

A hard coat laminate (1) comprising a substrate sheet (2), a hard coat layer (3) laminated on one main surface side of the substrate sheet, and a curl suppressing layer (4) laminated on the other main surface side of the substrate sheet ), the hard coat layer (3) is made of a material obtained by curing a composition containing a curable component and an inorganic filler, and the curl suppressing layer (4) is made of a material obtained by curing a composition containing a curable component, and The thickness of (2) is 25 to 100 µm, the thickness of the hard coat layer 3 is 20 to 50 µm, and the ratio of the thickness of the hard coat layer 3 to the thickness of the base sheet 2 is 0.2 to 2, , A hard coat laminate (1) in which the ratio of the thickness of the curl suppressing layer 4 to the thickness of the hard coat layer 3 is 0.2 to 2. Such a hard coat laminate 1 has a high surface hardness, and curl is suppressed.

Description

Hard coat laminate and its manufacturing method TECHNICAL FIELD [HARD COATED LAMINATE AND METHOD FOR PRODUCING SAME}

The present invention relates to a hard coat laminate comprising a base sheet and a hard coat layer, and a method of manufacturing the same.

In recent years, in various electronic devices, various displays such as a liquid crystal display (LCD), a plasma display (PDP), an organic EL display (OELD), and a touch panel are widely used. On the surface of these various displays, a hard coat film having a hard coat layer is usually formed in order to prevent scratches from occurring. Energy ray-curable resin is generally used for the hard coat layer.

The hard coat film is required to have a high surface hardness from the viewpoint of protection from scratches. Here, in order to improve the surface hardness of the hard coat film, there may be a method of thickening the hard coat layer formed on the surface side. However, when the hard coat layer is thickened in order to improve the surface hardness, curing shrinkage due to the energy ray-curable resin increases, and warping (curls) occurs in the hard coat film. That is, the improvement of the surface hardness and the suppression of curl were in the relationship of the trade-off.

Among these, a method of suppressing curling of a hard coat film by forming first and second hard coat layers on both sides of a base film and defining the layer thickness and curing degree of the first and second hard coat layers in a predetermined range It has been proposed (see Patent Document 1).

Patent Document 1: Japanese Laid-Open Patent Publication No. 2012-240235

However, in the method of Patent Document 1, since it is necessary to define the difference in layer thickness between the first and second hard coat layers in a predetermined range, the hard coat layer is sufficiently thick (for example, the thickness is set to 10 μm or more. It was difficult to do), and it was impossible to obtain a hard coat laminate of high hardness.

The present invention has been made in view of such a reality, and an object of the present invention is to provide a hard coat laminate having high surface hardness and suppressed curl.

In order to achieve the above object, first, the present invention provides a substrate sheet, a hard coat layer laminated on one main surface side of the substrate sheet, and curl suppression laminated on the other main surface side of the substrate sheet. A hard coat laminate having a layer, wherein the hard coat layer is made of a material obtained by curing a composition containing a curable component and an inorganic filler, and the curl suppressing layer is made of a material obtained by curing a composition containing a curable component. , The thickness of the base sheet is 25 to 100 µm, the thickness of the hard coat layer is 20 to 50 µm, the ratio of the thickness of the hard coat layer to the thickness of the base sheet is 0.2 to 2, and the hard coat It provides a hard coat laminate, characterized in that the ratio of the thickness of the curling inhibiting layer to the thickness of the layer is 0.2 to 2 (Invention 1).

The hard coat laminate according to the above invention (invention 1) has a hard coat layer made of a material obtained by curing a composition containing an inorganic filler in addition to a curable component, the thickness of the base sheet is 25 μm or more, and the hard coat When the thickness of the layer is 20 µm or more and the ratio of the thickness of the hard coat layer to the thickness of the base sheet is 0.2 or more, it has a high surface hardness. Further, according to the above invention (invention 1), a curl suppressing layer made of a material obtained by curing a composition containing a curable component is provided, and the ratio of the thickness of the curl suppressing layer to the thickness of the hard coat layer is 0.2 to 2, Curing shrinkage due to the hard coat layer and curing shrinkage due to the curl suppression layer are canceled out. Therefore, the hard coat laminate according to the invention (invention 1) has curling suppressed.

In the above invention (invention 1), it is preferable that the pencil hardness measured in accordance with JIS K 5600-5-4 of the hard coat layer is 5H or more (invention 2).

In the above invention (Inventions 1 and 2), the composition constituting the curl suppressing layer is preferably the same as the composition constituting the hard coat layer (Invention 3).

In the above invention (Inventions 1 to 3), the inorganic filler is preferably at least one selected from reactive silica and titanium oxide (Invention 4).

In the above invention (Invention 1 to 4), in dimensions of 10 cm in length and 10 cm in width, it is preferable that the total value of the heights of the warpage of the four corners is 5 cm or less (Invention 5).

In the above invention (Invention 1 to 5), it is preferable that the curable component in the hard coat layer composition and the curable component in the curl suppression layer composition are an energy ray curable component (Invention 6).

Secondly, the present invention is a method of manufacturing a hard coat laminate according to Invention 6, wherein a first layer made of the hard coat layer composition is laminated on one main surface side of a substrate sheet, and the substrate sheet of the first layer A laminate in which a cover sheet was laminated on the opposite side of the laminate was prepared, a second layer made of the composition for curl suppressing layer was formed on the other main surface side of the base sheet in the laminate, and irradiated with energy rays. The first layer and the second layer are cured to provide a method for producing a hard coat layered product, comprising a hard coat layer and a curl suppressing layer (invention 7).

The hard coat laminate according to the present invention has a high surface hardness and a curl is suppressed.

1 is a cross-sectional view of a hard coat laminate according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described.

1 is a cross-sectional view of a hard coat laminate according to an embodiment of the present invention. The hard coat laminate 1 according to the present embodiment includes a base sheet 2, a hard coat layer 3 laminated on one main surface side of the base sheet (upper side in FIG. 1), and a base sheet ( 2) It is comprised with the curl suppressing layer 4 laminated|stacked on the other main surface side (lower side in FIG. 1).

In the hard coat laminate (1) according to the present embodiment, the hard coat layer (3) is made of a material obtained by curing a composition containing a curable component and an inorganic filler, and the curl suppressing layer (4) contains a curable component. The composition is made of a cured material, the thickness of the base sheet 2 is 25 to 100 µm, the thickness of the hard coat layer 3 is 20 to 50 µm, and the hard coat layer relative to the thickness of the base sheet 2 The ratio of the thickness of (3) is 0.2 to 2, and the ratio of the thickness of the curl suppressing layer 4 to the thickness of the hard coat layer 3 is 0.2 to 2.

The hard coat laminate according to the present embodiment has high surface hardness and suppressed curl by having the above configuration.

(1) base sheet

The base sheet 2 of the hard coat laminate 1 according to the present embodiment may be appropriately selected according to the use of the hard coat laminate 1, but the hard coat layer 3 and the curl suppressing layer 4 It is preferable to use a resin film having good affinity for. By using a resin film for the base sheet 2, the hard coat laminate 1 according to the present embodiment has excellent bending resistance, and can be transported and stored in a wound body or from a wound body. Handling of the hard coat laminate 1 such as processing after unwinding (for example, processing by roll-to-roll, etc.) becomes easy. Moreover, when a transparent resin film is used as a resin film, since the hard coat laminated body 1 concerning this embodiment can be used for an optical use, it is especially preferable.

Examples of such resin films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyolefin films such as polyethylene films and polypropylene films, cellophane, diacetylcellulose films, and triacetylcellulose. Film, acetylcellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether Ether ketone film, polyether sulfone film, polyetherimide film, fluororesin film, polyamide film, polyimide film, polyamideimide film, acrylic resin film, polyurethane resin film, norbornene polymer film, cyclic olefin film Resin films such as polymer films, cyclic conjugated diene polymer films, and vinyl alicyclic hydrocarbon polymer films, or laminated films thereof. Among them, for reasons such as easy to obtain high hardness and excellent transparency when used as the hard coat laminate (1), polyethylene terephthalate film, polyethylene naphthalate film, polyamide film, polyimide film, and polyamide A mid film, a polycarbonate film, a triacetyl cellulose film, a polyvinyl alcohol film, a cyclic olefin polymer film, a polyether sulfone film, etc. are preferable, and in particular, a polyethylene terephthalate film, a polyethylene naphthalate film, a triacetyl cellulose film, and a poly An amide film, a polyamideimide film, etc. are preferable.

In addition, in the base sheet (2), for the purpose of improving the adhesion to the layer formed on the surface (such as the hard coat layer (3) or the curl suppression layer (4)), if desired, one or both sides are treated with a primer. , The surface treatment can be performed by an oxidation method, an uneven method, or the like. Examples of the oxidation method include corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone-ultraviolet treatment, and the like, and examples of the unevenness method include a sandblast method and a solvent treatment method. These surface treatment methods are appropriately selected depending on the type of the base sheet 2. As an example, a resin film, in particular a polyethylene terephthalate film, in which an easy-adhesion layer was formed by primer treatment is preferably used.

The thickness of the base sheet 2 is 25 to 100 µm, preferably 35 to 100 µm, particularly preferably 35 to 75 µm, and more preferably 50 to 75 µm. When the thickness of the base sheet 2 is 25 µm or more, high hardness is obtained when it is set as the hard coat laminate 1. In addition, if the thickness of the base sheet 2 is 25 µm or more, irregularities of the adherend are prevented when the hard coat laminate 1 according to the present embodiment is applied to another member (adherent) in the manufacture of various displays, etc. By absorbing, the surface of the display (the surface of the hard coat laminate 1 according to the present embodiment) can be made flat. On the other hand, when the thickness of the base sheet 2 is 100 µm or less, the hard coat laminate 1 according to the present embodiment has sufficient bending resistance and is easy to handle.

(2) Hard coat layer

The hard coat layer 3 of the hard coat laminate 1 according to the present embodiment is laminated on one main surface side (upper side in Fig. 1) of the base sheet 2, and the hard coat laminate 1 Gives high surface hardness to

The hard coat layer 3 of the hard coat layered product 1 according to the present embodiment cured a composition containing a curable component and an inorganic filler (hereinafter, this may be referred to as a “hard coat layer composition”). It is made of materials.

(2-1) curable component

As the curable component, an energy ray curable component, a heat curable component, or the like can be used, but an energy ray curable component is preferable.

It does not specifically limit as an energy ray-curable component, What is necessary is just to select suitably what suits the performance to be given to the hard coat layer 3, such as high hardness. Here, the term “energy rays” refers to those having both energy among electromagnetic waves or charged particle rays, and specifically, ultraviolet rays, electron rays, and the like are exemplified. Among the energy rays, ultraviolet rays that are easy to handle are particularly preferred.

Specific examples of the energy ray-curable component include polyfunctional (meth) acrylate-based monomers, (meth) acrylate-based prepolymers, and polymers having energy ray-curing properties. Among them, polyfunctional (meth) acrylate-based monomers And/or a (meth)acrylate-based prepolymer. The polyfunctional (meth)acrylate-based monomer and the (meth)acrylate-based prepolymer may be used individually or in combination of both. In addition, in this specification, (meth)acrylate means both an acrylate and a methacrylate. Other similar terms are the same.

As a polyfunctional (meth)acrylate-based monomer, for example, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate , Polyethylene glycol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, dicyclopentanyldi(meth)acrylate, caprolactone modified dicyclopentenyldi(meth)acrylate, ethylene oxide modified Phosphoric acid di(meth)acrylate, allylated cyclohexyldi(meth)acrylate, isocyanurate di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate , Propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, propionic acid modified And polyfunctional (meth)acrylates such as dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate. These may be used individually by 1 type, and may be used in combination of 2 or more types.

On the other hand, examples of the (meth)acrylate-based prepolymer include prepolymers such as polyester acrylate, epoxy acrylate, urethane acrylate, and polyol acrylate.

As a polyester acrylate prepolymer, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyhydric carboxylic acid and a polyhydric alcohol with (meth)acrylic acid, or It can be obtained by esterifying the hydroxyl group at the terminal of an oligomer obtained by adding an alkylene oxide to a carboxylic acid with (meth)acrylic acid.

The epoxy acrylate prepolymer can be obtained, for example, by reacting (meth)acrylic acid with an oxysilane ring of a relatively low molecular weight bisphenol type epoxy resin or a novolak type epoxy resin for esterification.

The urethane acrylate prepolymer can be obtained, for example, by esterifying a polyurethane oligomer obtained by reaction of a polyether polyol or a polyester polyol with a polyisocyanate with (meth)acrylic acid.

The polyol acrylate prepolymer can be obtained by esterifying the hydroxyl group of a polyether polyol with (meth)acrylic acid, for example.

The above prepolymers may be used alone or in combination of two or more.

In the case of using a polymer having energy ray-curable properties as the energy ray-curable component, the polymer is, for example, a (meth)acrylic acid ester copolymer having an energy ray-curable group in the side chain (hereinafter referred to as ``energy ray-curable (meth)acrylic acid Ester copolymer (A)".) can be used. The energy ray-curable (meth)acrylic acid ester copolymer (A) is preferably obtained by reacting an acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound (a2) having a substituent bonded to the functional group. Do.

The acrylic copolymer (a1) contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or a derivative thereof.

The functional group-containing monomer contained as a structural unit of the acrylic copolymer (a1) is a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group in the molecule, and is preferably a hydroxyl group. An unsaturated compound containing an actual group or an unsaturated compound containing a carboxyl group is used.

More specific examples of such a functional group-containing monomer include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl acryl. And carboxyl group-containing compounds such as hydroxyl group-containing acrylates such as rate, acrylic acid, methacrylic acid, and itaconic acid, and these are used alone or in combination of two or more.

Examples of the (meth)acrylic acid ester monomer contained in the acrylic copolymer (a1) as a structural unit include cycloalkyl (meth)acrylate, benzyl (meth)acrylate, alkyl (meth)acrylate having 1 to 18 carbon atoms in the alkyl group. Is used. Among these, particularly preferably, the alkyl group has 1 to 18 carbon atoms (meth)acrylate alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth) Acrylate, 2-ethylhexyl (meth)acrylate, and the like are used.

The acrylic copolymer (a1) contains a structural unit derived from the functional group-containing monomer in a proportion of usually 3 to 100 mass%, preferably 5 to 40 mass%, particularly preferably 10 to 30 mass%, ( Constituent units derived from a meth)acrylic acid ester monomer or a derivative thereof are usually contained in an amount of 0 to 97% by mass, preferably 60 to 95% by mass, and particularly preferably 70 to 90% by mass.

The acrylic copolymer (a1) is obtained by copolymerizing a functional group-containing monomer as described above with a (meth)acrylic acid ester monomer or a derivative thereof by a conventional method, but in addition to these monomers, a small amount (for example, 10% by mass or less, preferably Preferably, vinyl formate, vinyl acetate, styrene, or the like may be copolymerized at a ratio of 5% by mass or less.

The substituent that the unsaturated group-containing compound (a2) has can be appropriately selected according to the kind of the functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, when the functional group is a hydroxyl group, an amino group or a substituted amino group, an isocyanate group or an epoxy group is preferable as the substituent, and when the functional group is a carboxyl group, an aziridinyl group, an epoxy group or an oxazoline group is preferable as the substituent, and a functional group When is an epoxy group, an amino group, a carboxyl group, or an aziridinyl group is preferable as the substituent. One such substituent is contained for each molecule of the unsaturated group-containing compound (a2).

Further, the unsaturated group-containing compound (a2) contains 1 to 5, preferably 1 to 2, energy ray-curable unsaturated groups (carbon-carbon double bonds) per molecule. Specific examples of such an unsaturated group-containing compound (a2) include, for example, acryloyloxyethyl isocyanate, methacryloyloxyethyl isocyanate, meth-isopropenyl-α,α-dimethylbenzyl isocyanate, and methacrylo. Monoisocyanate and allyl isocyanate; Acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or a polyisocyanate compound, and hydroxyethyl (meth)acrylate; Acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or a polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate; Glycidyl (meth)acrylate; (Meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, and the like.

The unsaturated group-containing compound (a2) is used in a ratio of usually 20 to 100 equivalents, preferably 40 to 100 equivalents, and particularly preferably 60 to 100 equivalents per 100 equivalents of the functional group-containing monomer of the acrylic copolymer (a1). do.

The energy ray-curable (meth)acrylic acid ester copolymer (A) is obtained by reacting the acrylic copolymer (a1) and the unsaturated group-containing compound (a2) in an organic solvent by a conventional method. The weight average molecular weight (Mw) of the energy ray-curable (meth)acrylic acid ester copolymer (A) is preferably 10,000 to 100,000, particularly preferably 20,000 to 80,000, and further preferably 30,000 to 60,000. In addition, the weight average molecular weight (Mw) in this specification is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

In addition, when a thermosetting component is used as the curable component, examples of the thermosetting component that can be used include epoxy resins, polyimide resins, phenolic resins, silicone resins, cyanate resins, bismaleimide triazine resins, Allylated polyphenylene ether resins (heat curable PPE), formaldehyde resins, unsaturated polyesters, or copolymers thereof, and the like, among others, epoxy resins are preferred.

The curable component constituting the hard coat layer 3 of the present embodiment preferably has a glass transition point of 130°C or higher after curing, more preferably 150°C or higher, and particularly preferably a glass transition point not observed. Here, in the manufacture of the touch panel, the process of heating the hard coat laminate 1 may be included. In this case, the heat shrinkage of the hard coat laminate 1 becomes a problem, but the glass transition point satisfies the above conditions. By using the curable component described above, the hard coat layer 3 is also excellent in heat resistance, and excellent heat resistance can be imparted to the hard coat layered product 1.

(2-2) inorganic filler

The composition for a hard coat layer constituting the hard coat layer 3 of the present embodiment contains an inorganic filler in addition to the above-described curable component. By containing the inorganic filler, high surface hardness is imparted to the hard coat layer 3 of the present embodiment.

Preferred inorganic fillers include powders such as silica, alumina, boehmite, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, boron nitride, and zirconium oxide, beads in which these are spheroidized, single crystal fibers, and glass fibers. And these may be used alone or in combination of two or more. Among these, silica, alumina, boehmite, titanium oxide, zirconium oxide, and the like are preferable, and silica, titanium oxide, and zirconium oxide are more preferable. In particular, since silica has light transmittance, it can be preferably used when the hard coat laminate 1 according to the present embodiment is used for an optical application.

In addition, it is preferable that the inorganic filler is surface-modified. Reactive silica can be illustrated as such a particularly preferred inorganic filler.

In the present specification, "reactive silica" refers to silica fine particles surface-modified with an organic compound having an energy ray-curable unsaturated group. The silica fine particles (reactive silica) surface-modified with an organic compound having an energy ray-curable unsaturated group is, for example, a silanol group on the surface of the silica fine particles having an average particle diameter of about 0.5 to 500 nm, and preferably having an average particle diameter of 1 to 200 nm. It can be obtained by reacting an energy ray-curable unsaturated group-containing organic compound having a (meth)acryloyl group which is a functional group capable of reacting with the silanol group.

As an energy ray-curable unsaturated group-containing organic compound having a functional group capable of reacting with a silanol group, for example, general formula (I)

[Formula 1]

(In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a halogen atom,

[Formula 2]

It is a group represented by.)

The compound represented by and is preferably used.

Examples of such compounds include (meth)acrylic acid, (meth)acrylic acid chloride, (meth)acryloyloxyethyl isocyanate, (meth)acrylic acid glycidyl, (meth)acrylic acid 2,3-iminopropyl, (Meth)acrylic acid derivatives such as 2-hydroxyethyl (meth)acrylate and acryloyloxypropyltrimethoxysilane can be used. These (meth)acrylic acid derivatives may be used singly or in combination of two or more.

Organic-inorganic hybrid material containing such reactive silica (silica fine particles surface-modified with an organic compound having an energy ray-curable unsaturated group) and the above-described polyfunctional (meth)acrylate-based monomer and/or (meth)acrylate-based prepolymer As for the furnace, for example, brand names "Opstar Z7530", "Opstar Z7524", "Opstar TU4086", "Opstar Z7537" (above, manufactured by JSR), and the like can be used.

The inorganic filler used in the present embodiment preferably has an average particle diameter of 1 to 200 nm, particularly preferably 10 to 200 nm, and more preferably 20 to 200 nm. When the average particle diameter of the inorganic filler is 1 nm or more, the hard coat layer 3 obtained by curing the composition for a hard coat layer has a higher surface hardness. In addition, when the average particle diameter of the inorganic filler is 200 nm or less, light scattering is less likely to occur in the obtained hard coat layer 3, and the transparency of the hard coat layer 3 increases. Therefore, by using the above-described transparent resin film together as the hard coat layer 3 and the base sheet 2, the hard coat laminate 1 according to the present embodiment has high transparency, and is particularly preferable for optical applications. Can be used. In addition, the average particle diameter of the inorganic filler is measured by the zeta potential measurement method.

The content of the inorganic filler in the hard coat layer (3) of the present embodiment is preferably 10 to 85% by volume, particularly preferably 20 to 80% by volume, and 40 to 80% by volume with respect to the hard coat layer (3). It is more preferably 70% by volume, and most preferably 45 to 65% by volume. When the content of the inorganic filler is 10% by volume or more, the surface hardness imparted to the hard coat layer 3 is higher. On the other hand, when the content of the inorganic filler is 85% by volume or less, layer formation using the composition for a hard coat layer becomes easy.

In addition, the content of the inorganic filler in the present specification is determined as follows. The organic component is burned according to JIS 7250-1, the mass% of the inorganic filler is calculated from the resulting ash, and the true density of the inorganic filler is determined again according to JIS Z 8807. Thereafter, the density of the hard coat layer 3 is determined from JIS Z 8807, and the volume% of the inorganic filler is determined from the measured values of the mass% of the inorganic filler, the true density of the inorganic filler, and the density of the hard coat layer 3.

(2-3) Other ingredients

The composition for a hard coat layer constituting the hard coat layer 3 of the present embodiment may contain various additives in addition to the above-described curable component and inorganic filler. As various additives, for example, photopolymerization initiator, ultraviolet absorber, antioxidant, light stabilizer, antistatic agent, silane coupling agent, aging inhibitor, thermal polymerization inhibitor, colorant, surfactant, storage stabilizer, plasticizer, lubricant, antifoaming agent, Organic fillers, wettability improving agents, coating surface improving agents, and the like.

As a photoinitiator, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl Phenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2(hydroxy-2- Propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone, 2 -Aminoanthraquinone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chloro thioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyl dimethyl ketal, aceto Phenone dimethyl ketal, p-dimethylaminobenzoic acid ester, and the like. These may be used individually by 1 type, and may be used in combination of 2 or more types. The content of the photopolymerization initiator in the composition for a hard coat layer is usually selected in the range of 0.2 to 20 parts by mass per 100 parts by mass of the energy ray-curable component.

(2-4) Physical properties of the hard coat layer

The thickness of the hard coat layer 3 is 20 to 50 µm, preferably 25 to 50 µm. When the thickness of the hard coat layer 3 is 20 μm or more, sufficient surface hardness is imparted to the hard coat laminate 1 according to the present embodiment. On the other hand, when the thickness of the hard coat layer is 50 μm or less, the hard coat laminate (1) is excellent in bending resistance and is easy to handle, and the hard coat laminate (1) is thickened without the need, or the manufacturing cost is reduced. It can be prevented from increasing or doing.

In addition, in the hard coat layered product (1) of the present embodiment, the ratio of the thickness of the hard coat layer 3 to the thickness of the base sheet 2 is 0.2 to 2, preferably 0.25 to 1.5, particularly preferably Preferably, it is 0.25-1, and more preferably 0.5-1. When the ratio of the thickness of the hard coat layer 3 to the thickness of the base sheet 2 is 0.2 or more, sufficient surface hardness is imparted to the hard coat laminate 1 according to the present embodiment. On the other hand, when the ratio of the thickness is 2 or less, the hard coat laminate 1 is excellent in bending resistance, and handling becomes easy.

The pencil hardness measured in accordance with JIS K 5600-5-4 of the hard coat layer 3 is preferably 5H or more, particularly preferably 6H or more, and even more preferably 8H or more. The hard coat layered product 1 in which the hard coat layer 3 satisfies these conditions has a very high surface hardness and is excellent in scratch resistance.

(3) curl suppression layer

The curl suppressing layer 4 of the hard coat layered product 1 according to the present embodiment is the side of the other main surface of the base sheet 2 (the surface opposite to the surface on which the hard coat layer 3 is laminated) ( By laminating on the lower side in FIG. 1), the curing shrinkage of the hard coat layer 3 is canceled by the curing shrinkage of the curl suppressing layer 4, and curling of the hard coat layered product 1 is suppressed.

The curl suppression layer 4 of the hard coat laminate 1 according to the present embodiment is made of a material obtained by curing a composition containing a curable component (hereinafter, this may be referred to as a "curl suppression layer composition"). will be.

As the curable component of the composition for the curl suppressing layer, a curable component according to the performance to be imparted to the curl suppressing layer 4 may be appropriately selected, but in particular, from the viewpoint of suppressing curl, the curing shrinkage of the same degree as the hard coat layer 3 It is preferable to select a curable component having As a specific curable component, the same components as those used in the composition for a hard coat layer described above can be used.

Moreover, it is preferable that the composition for curl suppressing layers contains an inorganic filler in addition to a curable component. Here, as the inorganic filler used in the composition for a curl suppressing layer, it is preferable to use the same as that used in the composition for a hard coat layer, and the content of the inorganic filler in the composition for a curl suppressing layer is the same as that of the composition for a hard coat layer. It is desirable to do so. When the composition for the curl suppressing layer contains the inorganic filler in this way, the curing shrinkage of the curl suppressing layer 4 and the curing shrinkage of the hard coat layer 3 become the same degree, and the curl of the hard coat layered product 1 is more effective. Is suppressed.

And the composition for curl suppressing layer may contain various additives other than the above-mentioned component. As various additives, the same additives as those used in the above-described hard coat layer composition may be used.

It is preferable that the composition for a curl suppressing layer be the same as the composition for a hard coat layer described above. By making the composition for the curl suppressing layer and the composition for the hard coat layer the same, the curing shrinkage of the curl suppressing layer 4 and the curing shrinkage of the hard coat layer 3 become the same degree, and the curl of the hard coat laminate 1 is more Effectively suppressed.

In the hard coat layered product (1) of the present embodiment, the ratio of the thickness of the curl suppressing layer 4 to the thickness of the hard coat layer 3 is 0.2 to 2, preferably 0.2 to 1, particularly preferably It is preferably from 0.3 to 0.8, more preferably from 0.5 to 0.8. When the ratio of the thickness of the curl suppressing layer 4 to the thickness of the hard coat layer 3 is 0.2 to 2, the curing shrinkage due to the hard coat layer 3 and the curing shrinkage due to the curl suppressing layer 4 are canceled out. , Curling of the hard coat laminate 1 according to the present embodiment is suppressed.

More specifically, the thickness of the curl suppressing layer 4 is preferably 4 to 100 µm, particularly preferably 5 to 100 µm, even more preferably 20 to 50 µm, and most preferably 25 to 50 µm. desirable. When the thickness of the curl suppressing layer 4 is in the above range, the ratio of the thickness of the curl suppressing layer 4 to the thickness of the hard coat layer 3 easily satisfies the above-described condition, and the hard coating according to the present embodiment The curl of the coat laminate 1 is suppressed more effectively.

(4) Physical properties of hard coat laminate

In the hard coat laminate (1) according to the present embodiment, in dimensions of 10 cm in length and 10 cm in width, the total value of the heights of the four corners is preferably 5 cm or less, more preferably 3 cm or less, It is particularly preferably 2 cm or less, and most preferably 1 cm or less. The hard coat laminate 1 that satisfies these conditions is one in which warpage (curl) is suppressed. In addition, the details of a specific measurement method are shown in the test example mentioned later.

In addition, the hard coat laminate (1) according to the present embodiment has a minimum mandrel diameter of 32 mm or less in which cracks do not occur in the bending resistance test by the cylindrical mandrel method in accordance with JIS K 5600-5-1. It is preferable, it is more preferable that it is 25 mm or less, and it is especially preferable that it is 20 mm or less. The hard coat laminate (1) that satisfies these conditions is not easily cracked or peeled off even when it is wound up with a winding body or released from the winding body, and has excellent bending resistance, making it easy to handle. do.

The haze value of the hard coat layered product 1 according to the present embodiment is preferably 3.0% or less, more preferably 1.0% or less, particularly preferably 0.8% or less, and still more preferably 0.7% or less. When the haze value is 3.0% or less, transparency is high, and the hard coat layered product 1 according to the present embodiment is preferable as an optical use. In addition, the haze value is a value measured in accordance with JIS K 7136-2000 using a haze meter "NDH5000" manufactured by Nippon Denshoku Kogyo.

(5) Manufacturing method of hard coat laminate (1)

In the hard coat laminate (1) according to the present embodiment, for example, a composition for a hard coat layer is applied to one side of the base sheet (2), and a composition for a curl suppressing layer is applied to the other side. It is obtained by forming the hard coat layer (3) and the curl suppressing layer (4) by curing them. Hereinafter, the case where the composition for a hard coat layer and the composition for a curl suppressing layer contains an energy ray-curable component as a curable component is demonstrated. In addition, since the layers of the composition for a hard coat layer and the composition for a curl suppressing layer before curing are basically composed of a coating film, they are hereinafter mainly referred to as "coating films". However, the present invention is not limited to this.

As a specific manufacturing method of the hard coat laminated body 1 according to the present embodiment, two described below are exemplified, but are not limited to these methods.

The first method is a coating film of a layer of a composition for a hard coat layer applied or bonded on one side of the base sheet 2, and a layer of a composition for a curl suppressing layer applied or bonded on the other side of the base sheet 2 This is a method of curing the coating film at once to obtain a hard coat layer 3 and a curl suppressing layer 4, respectively. As an example, first, a first coating film made of a composition for a hard coat layer (a layer that becomes the hard coat layer 3 after curing) is formed on one side of the substrate sheet 2, and the substrate in the first coating film By laminating a cover sheet on the side opposite to the sheet 2, a laminate comprising a base sheet/first coating film/cover sheet is produced. At this time, a first coating film may be formed on the cover sheet, and the first coating film having the cover sheet may be bonded to one surface of the base sheet 2. Moreover, as a cover sheet, what was illustrated as a resin film above can be used.

The first coating film made of the hard coat layer composition is an energy ray-curable component, an inorganic filler, and other materials constituting the hard coat layer composition, and, if desired, a coating agent containing a further solvent is prepared, and this is a base sheet (2) or a cover. It is formed by applying to a sheet and drying. The coating agent may be applied by a conventional method, for example, a bar coat method, a knife coat method, a Meyer bar method, a roll coat method, a blade coat method, a die coat method, or a gravure coat method. Drying can be performed by heating at 80-150 degreeC for about 30 seconds-5 minutes, for example.

Subsequently, on the other side of the base sheet 2 in the laminate (the side where the base sheet 2 is exposed), a second coating film made of the composition for a curl suppressing layer (after curing, the curl suppressing layer 4) was formed. Layer) is formed, and a cover sheet is further laminated on the surface opposite to the base sheet 2 in the second coating film (the lower surface in Fig. 1). At this time, a second coating film may be formed on the cover sheet, and the second coating film having the cover sheet may be bonded to the other surface of the base sheet 2.

The second coating made of the composition for the curl suppressing layer is to prepare a coating agent containing an energy ray-curable component and other materials constituting the composition for the curl suppressing layer, and if desired, a coating agent containing additional solvent, and this is applied to the base sheet (2) or the cover sheet And dried. Steps such as coating and drying may be performed in the same manner as in the case of forming the first coating film made of the composition for a hard coat layer.

The obtained cover sheet/first coating film/substrate sheet (2)/second coating/cover sheet was irradiated with energy rays from one or both of the main surfaces, and the first coating film and curl made of the composition for a hard coat layer The 2nd coating film made of the composition for suppression layers is hardened, and it is set as the hard coat layer 3 and the curl suppression layer 4, respectively.

Curing of the first and second coating films (formation of the hard coat layer 3 and the curl suppressing layer 4) is performed by irradiating the coating films with active energy rays such as ultraviolet rays and electron beams. Ultraviolet irradiation can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, or the like, and the irradiation amount of the ultraviolet ray is preferably about 50 to 1000 mW/cm 2 of illuminance and 50 to 1000 mJ/cm 2 of light. On the other hand, the electron beam irradiation can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad.

As described above, the cover sheet is laminated further outside the hard coat layer 3, and the cover sheet is laminated further outside the curl suppressing layer 4, and the hard coat laminate according to the present embodiment (1) can be obtained.

Moreover, in the above-described method, the composition for a hard coat layer and the composition for a curl suppressing layer may be replaced. That is, firstly, a first coating film made of the composition for a curl suppressing layer is formed, and then a second coating film made of the composition for a hard coat layer is formed, and thereafter, they may be cured to produce a hard coat laminate (1).

Here, the cover sheet is used for the purpose of supporting the laminate in the manufacturing process or blocking oxygen in the air that inhibits the energy ray curing reaction from the coating film of the composition for a hard coat layer. ) Is removed when used. Further, the cover sheet on the side of the second coating film can be omitted, and in that case, it is preferable to perform the curing treatment in an atmosphere having a low oxygen concentration (eg, in a nitrogen atmosphere).

In the second method, a coating film of the composition for a hard coat layer applied or bonded to one side of the base sheet 2 and a coating film of the composition for curl suppressing layer applied or bonded to the other side of the base sheet 2 are separately applied. It is a method of curing by a process to form the hard coat layer 3 and the curl suppressing layer 4, respectively.

As an example, first, as a first step, a hard coat layer 3 is formed on one main surface side of the base sheet 2. Specifically, in the same manner as in the first method described above, a laminate made of a first coating film/cover sheet made of a base sheet/hard coat layer composition is produced. The obtained laminate is irradiated with energy rays from one or both main surfaces to cure the first coating film made of the composition for a hard coat layer to obtain a hard coat layer (3).

Subsequently, with respect to the obtained laminate, as a second step, the curl suppressing layer 4 is formed on the other surface of the base sheet 2 (the surface where the base sheet 2 is exposed). Specifically, a second coating film and a cover sheet made of a composition for a curl suppressing layer are laminated on the surface of the laminate on which the hard coat layer 3 is formed, on which the base sheet 2 is exposed. The second coating film may be formed by directly applying to the base sheet 2, or may be bonded to the base sheet 2 by applying to the cover sheet.

The obtained laminate is irradiated with energy rays from one or both of the main surfaces to cure the second coating film made of the composition for a curl suppressing layer, thereby forming the curl suppressing layer 4. Thereby, the cover sheet is laminated further outside the hard coat layer 3, and the cover sheet is laminated further outside the curl suppressing layer 4, and the hard coat laminate 1 according to the present embodiment is prepared. Can be obtained.

Further, in the second method, the composition for a hard coat layer and the composition for a curl suppressing layer may be replaced. That is, in the first step, a first coating film made of the composition for a curl suppressing layer is formed on one surface of the base sheet 2, and the first coating film is cured to obtain the curl suppressing layer 4. Subsequently, in the second step, a second coating film made of the composition for a hard coat layer is formed on the other side of the base sheet 2 (the side where the base sheet 2 is exposed), and this is cured to obtain a hard coat layer. do. In this way, you may manufacture the hard coat laminated body (1).

In addition, in the second method, one or both of the two cover sheets can be omitted, and in that case, it is preferable to perform the curing treatment in an atmosphere with a low oxygen concentration (for example, in a nitrogen atmosphere). Do.

According to the method described above, the hard coat laminate (1) according to the present embodiment can be produced. Among them, the first method is preferable, and in particular, in the first method, a first coating film comprising a composition for a hard coat layer and A method of forming a second coating film made of the composition for a curl suppressing layer and irradiating an energy ray to form the hard coat layer 3 and the curl suppressing layer 4 is preferred.

(6) Use of the hard coat laminate (1)

The use of the hard coat layered product 1 according to the present embodiment can be suitably used for applications requiring both high surface hardness and curl suppression. In particular, in the case of having transparency such as a small haze value of the hard coat laminate 1, an optical member such as a liquid crystal display (LCD), a plasma display (PDP), an organic EL display (OELD), and furthermore It can be used as a surface layer of various displays such as touch panels. Among them, the hard coat laminate 1 according to the present embodiment is particularly preferable as a surface layer of a touch panel because it has a high surface hardness.

Further, in the hard coat laminate 1 according to the present embodiment, an adhesive agent layer, a barrier layer, a conductive layer, a low reflection layer, an easy-to-print layer, an antifouling layer, and the like may be laminated.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents falling within the technical scope of the present invention.

For example, another layer may be interposed between the base sheet 2 in the hard coat laminate (1) and the hard coat layer (3) and/or the curl suppressing layer (4).

Example

Hereinafter, the present invention will be described more specifically by examples and the like, but the scope of the present invention is not limited to these examples.

[Example 1]

Composition for hard coat layer (manufactured by JSR, brand name "Opstar Z7530", dipentaerythritol hexaacrylate (density: 1.25 g/cm 3) as energy ray curable component and reactive silica as inorganic filler (density: 2.1 g/cm 3) Was contained in a mass ratio of 40:60, inorganic filler content: 49 vol%, photopolymerization initiator: 3 mass%, solid content concentration: 73 mass%, solvent: methyl ethyl ketone), a polyethylene terephthalate (PET) film as a base sheet ( Toyobo Co., Ltd., brand name "Cosmoshine PET25A4300", thickness: 25 μm) was coated with a die coater so that the thickness after drying became 25 μm, and then treated at 80° C. for 1 minute to form a coating film of the composition for a hard coat layer. Formed. Subsequently, after bonding a cover sheet (manufactured by Toyobo, brand name "Cosmoshine PET38A4100") to the obtained coating film, ultraviolet (UV) irradiation from the cover sheet side of the obtained laminate (irradiance: 230 mW/cm 2, light quantity: 190 mJ/ Cm2) to cure the composition for a hard coat layer to form a hard coat layer (thickness: 25 µm).

Subsequently, the composition for a curl suppression layer (manufactured by JSR, brand name ``Opstar Z7530'', the same as the above-described hard coat layer composition) on the surface of the obtained laminate to which the cover sheet is not bonded (the surface where the base sheet is exposed). ) Was applied with a die coater so that the thickness after drying became 25 μm, and then treated at 80° C. for 1 minute to form a coating film of the composition for a curl suppressing layer. Next, after bonding a cover sheet (manufactured by Toyobo, brand name "Cosmoshine PET38A4300") to the obtained coating film, UV irradiation from the cover sheet side of the obtained laminate (irradiance: 230 mW/cm2, light quantity: 190 mJ/cm2) And curing the composition for a curl suppressing layer to form a curl suppressing layer (thickness: 25 µm). In this way, a laminate made of a cover sheet/hard coat layer/substrate sheet/curl suppression layer/cover sheet, that is, a hard coat laminate in a state in which a cover sheet is laminated on the outside of the hard coat layer and the curl suppressing layer, was obtained.

[Examples 2 to 8, Comparative Examples 1 to 4]

A hard coat laminate in the same manner as in Example 1, except that a PET film having the thickness shown in Table 1 was used as the base sheet, and the thickness of the hard coat layer and the thickness of the curl suppressing layer were changed to the values shown in Table 1. Was prepared.

[Example 9]

As a composition for a curl suppressing layer, 100 parts by mass of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Industries, Ltd.) as an energy ray-curable component and hydroxycyclohexylphenyl ketone as a photoinitiator (manufactured by BASF, brand name ``Irgacure 184'') ) A hard coat laminate in the same manner as in Example 1, except that 2.5 parts by mass of the mixture was used, a PET film having a thickness of 50 µm was used as the base sheet, and the thickness of the curl suppressing layer was changed to 5 µm. Was prepared.

(Example 10, Comparative Example 5)

A hard coat laminate was produced in the same manner as in Example 9, except that the thickness of the curl suppressing layer was changed to the value shown in Table 1.

[Comparative Example 6]

As a composition for a hard coat layer and a composition for a curl suppression layer, 100 parts by mass of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) as an energy ray-curable component and hydroxycyclohexylphenyl ketone (manufactured by BASF, trade name) as a photoinitiator Irgacure 184") A hard coat laminate was produced in the same manner as in Example 1, except that a mixture of 2.5 parts by mass was used and a PET film having a thickness of 100 µm was used as the base sheet.

[Test Example 1] (Measurement of pencil hardness)

Two cover sheets were peeled off from the hard coat laminates obtained in Examples and Comparative Examples, and the surface of the hard coat layer was exposed to fix it on a glass plate. Regarding the exposed hard coat surface, pencil hardness was measured using a pencil scratch hardness tester (manufactured by Yasuda Seiki Co., Ltd., product name "No.553-M") in accordance with JIS K 5600-5-4. The scratch speed was 1 mm/sec. Table 1 shows the results. In addition, a pencil hardness of 5H or more was evaluated as good (○), and a pencil hardness of 4H or less was evaluated as defective (x). Table 1 shows the results.

[Test Example 2] (Measurement of curl amount)

The hard coat laminates obtained in Examples and Comparative Examples were cut to be 10 cm long and 10 cm wide, and the cover sheet was removed to obtain a test piece. The obtained test piece was measured for the vertical distance (cm) from the table surface at the four corners in an atmosphere of 23°C and 50% RH, and the total value of the distances at four locations was defined as the amount of curl (cm). Table 1 shows the results. In addition, a curl amount of 5 cm or less was evaluated as good ((circle)), and a curling amount exceeding 5 cm was evaluated as defective (x). Table 1 shows the results.

As is clear from Table 1, the hard coat laminate obtained in Examples had a high surface hardness, and curl was suppressed. In contrast, the hard coat laminates obtained in Comparative Examples 1 to 3 had poor surface hardness, and the hard coat laminates obtained in Comparative Examples 4 to 5 had a remarkable degree of curling. In addition, the hard coat laminate obtained in Comparative Example 6 had a poor surface hardness and a remarkable degree of curling.

Industrial availability

The hard coat laminate of the present invention is preferably used for a surface layer protective sheet of various displays such as a liquid crystal display (LCD), a plasma display (PDP), an organic EL display (OELD), and a touch panel.

One … Hard coat laminate
2 … Base sheet
3… Hard coat layer
4 … Curl suppression layer

Claims (7)

A hard coat laminate comprising a substrate sheet, a hard coat layer laminated on one main surface side of the substrate sheet, and a curl suppressing layer laminated on the other main surface side of the substrate sheet,
The hard coat layer is made of a material obtained by curing a composition containing a curable component and an inorganic filler,
The curl suppressing layer is made of a material obtained by curing a composition containing a curable component and an inorganic filler,
The thickness of the base sheet is 25 to 100 μm,
The thickness of the hard coat layer is 20 to 50 ㎛,
The ratio of the thickness of the hard coat layer to the thickness of the base sheet is 0.2 to 2,
A hard coat laminate, characterized in that the ratio of the thickness of the curl suppressing layer to the thickness of the hard coat layer is 0.2 to 2. The method of claim 1,
The hard coat laminate, characterized in that the pencil hardness of the hard coat layer measured according to JIS K 5600-5-4 is 5H or more. The method of claim 1,
The composition constituting the curl suppressing layer is the same as the composition constituting the hard coat layer. The method of claim 1,
The inorganic filler contained in the composition constituting the hard coat layer is at least one selected from reactive silica and titanium oxide. The method of claim 1,
A hard coat laminate, characterized in that, in dimensions of 10 cm in length and 10 cm in width, the sum of the heights of the four corners is 5 cm or less. The method of claim 1,
The hard coat layered product, wherein the curable component in the hard coat layer composition and the curable component in the curl suppressing layer composition are energy ray curable components. As a method for producing the hard coat laminate according to claim 6,
To prepare a laminate in which a first layer made of the hard coat layer composition is laminated on one main surface side of the base sheet, and a cover sheet is laminated on the side opposite to the base sheet side of the first layer
Forming a second layer made of the composition for curl suppressing layer on the other main surface side of the base sheet in the laminate,
A method for producing a hard coat laminate, characterized in that the first layer and the second layer are cured by irradiation with energy rays to form a hard coat layer and a curl suppressing layer.

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