JP6097836B2 - Hard coat laminate and method for producing the same - Google Patents

Description

  The present invention relates to a hard coat laminate including a base sheet and a hard coat layer, and a method for producing the same.

  In recent years, 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 in various electronic devices. The surface of these various displays is usually provided with a hard coat film having a hard coat layer to prevent scratches. Generally, an energy ray curable resin is 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, it is conceivable to increase the thickness of the hard coat layer provided on the surface side. However, if the hard coat layer is thickened in order to improve the surface hardness, curing shrinkage due to the energy ray curable resin increases, and the hard coat film is warped (curled). That is, the improvement in surface hardness and curling suppression were in a trade-off relationship.

  Under such circumstances, the first and second hard coat layers are provided on both surfaces of the base film, and the layer thickness and the degree of cure of the first and second hard coat layers are defined within a predetermined range, A method for suppressing curling of a coated film has been proposed (see Patent Document 1).

JP 2012-240235 A

  However, in the method of Patent Document 1, since the layer thickness difference between the first and second hard coat layers needs to be regulated within a predetermined range, the hard coat layer is sufficiently thick (for example, the thickness is 10 μm or more). It was difficult to obtain a hard coat laminate with high hardness.

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

  In order to achieve the above object, first, the present invention provides a base sheet, a hard coat layer laminated on one main surface side of the base sheet, and the other main surface side of the base sheet. A hard coat laminate comprising a laminated curl suppression 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 suppression layer is cured. It is made of a material obtained by curing a composition containing an ionic 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 is 0.2-2, and the ratio of the thickness of the curl suppression layer to the thickness of the hard coat layer is 0.2-2. Provide a hard coat laminate ( Invention 1).

  The hard coat laminate according to the invention (invention 1) includes a hard coat layer made of a material obtained by curing a composition containing an inorganic filler in addition to a curable component, and the thickness of the base sheet is 25 μm or more. In addition, when the thickness of the hard coat 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, the surface has high surface hardness. Moreover, according to the said invention (invention 1), the curl suppression layer which consists of a material which hardened the composition containing a sclerosing | hardenable component is provided, and ratio of the thickness of the curl suppression layer with respect to the thickness of a hard-coat layer is 0. .2 or 2 offsets the curing shrinkage caused by the hard coat layer and the curing shrinkage caused by the curl suppressing layer. Therefore, the hard coat laminate according to the above invention (Invention 1) has curling suppressed.

  In the said invention (invention 1), it is preferable that the pencil hardness measured based on JISK5600-5-4 of the said hard-coat layer is 5H or more (invention 2).

  In the said invention (invention 1 and 2), it is preferable that the composition which comprises the said curl suppression layer is the same as the composition which comprises the said hard-coat layer (invention 3).

  In the said invention (invention 1-3), it is preferable that the said inorganic filler is at least 1 sort (s) chosen from reactive silica and a titanium oxide (invention 4).

  In the said invention (invention 1-4), it is preferable that the total value of the height of curvature of four corners is 5 cm or less in the dimension of 10 cm in length and 10 cm in width (invention 5).

  In the said invention (invention 1-5), it is preferable that the said curable component in the composition for said hard-coat layers and the said curable component in the said composition for curl suppression layers are energy-beam curable components. (Invention 6).

  2ndly, this invention is a method of manufacturing the hard-coat laminated body which concerns on invention 6, Comprising: The 1st layer which consists of a composition for said hard-coat layers is laminated | stacked on the one main surface side of a base material sheet. A laminate in which a cover sheet is laminated on the side opposite to the base sheet side of the first layer is prepared, and the curl suppressing layer is provided on the other main surface side of the base sheet in the laminate. A hard coat laminate comprising: forming a second layer comprising a composition; and curing the first layer and the second layer by irradiation with an energy beam to form a hard coat layer and a curl suppressing layer. A manufacturing method is provided (Invention 7).

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

It is sectional drawing of the hard-coat laminated body which concerns on one Embodiment of this invention.

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

  The hard coat laminate 1 according to the present embodiment is a composition in which 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. Made of a cured material, the thickness of the base sheet 2 is 25 to 100 μm, the thickness of the hard coat layer 4 is 20 to 50 μm, and the thickness of the hard coat layer 3 with respect to the thickness of the base sheet 2 The ratio of thickness 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 a high surface hardness and curling is suppressed by having the above-described 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. 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 is transported and stored in the state of the wound body, or is fed from the wound body. It becomes easy to handle the hard coat laminate 1 such as all processes (for example, roll-to-roll process). In addition, when a transparent resin film is used as the resin film, the hard coat laminate 1 according to the present embodiment can be used for optical applications, which is particularly preferable.

  Examples of such a resin film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyolefin films such as polyethylene film and polypropylene film, cellophane, diacetyl cellulose film, triacetyl cellulose film, acetyl cellulose 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, poly Etherimide film, fluororesin film, poly Mid film, polyimide film, polyamideimide film, acrylic resin film, polyurethane resin film, norbornene polymer film, cyclic olefin polymer film, cyclic conjugated diene polymer film, vinyl alicyclic hydrocarbon polymer film, etc. A resin film or a laminated film thereof may be mentioned. Among them, for the reason that high hardness is easily obtained when the hard coat laminate 1 is obtained, and because it is excellent in transparency, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyamide film, a polyimide film, a polyamideimide film, a polycarbonate film, A triacetyl cellulose film, a polyvinyl alcohol film, a cyclic olefin polymer film, a polyether sulfone film, and the like are preferable, and a polyethylene terephthalate film, a polyethylene naphthalate film, a triacetyl cellulose film, a polyamide film, a polyamideimide film, and the like are particularly preferable.

  Moreover, in the said base material sheet 2, with the objective of improving the adhesiveness with the layers (the hard-coat layer 3, the curl suppression layer 4, etc.) provided in the surface, a primer process and an oxidation method may be applied to one side or both sides as desired. The surface treatment can be performed by 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 examples of the unevenness method include a sand blast method and a solvent treatment method. These surface treatment methods are appropriately selected according to the type of the substrate sheet 2. As an example, a resin film, particularly a polyethylene terephthalate film, on which an easy-adhesion layer is formed by primer treatment is preferably used.

  The thickness of the base material sheet 2 is 25-100 micrometers, Preferably it is 35-100 micrometers, Especially preferably, it is 35-75 micrometers, More preferably, it is 50-75 micrometers. When the thickness of the base sheet 2 is 25 μm or more, high hardness is obtained when the hard coat laminate 1 is obtained. Moreover, when the thickness of the base material sheet 2 is 25 μm or more, when the hard coat laminate 1 according to the present embodiment is adhered to another member (adhered body) in manufacturing various displays and the like, The unevenness of the body can be absorbed, and the surface of the display (the surface of the hard coat laminate 1 according to this 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 this 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 this embodiment is laminated on one main surface side (upper side in FIG. 1) of the base sheet 2 and is higher than the hard coat laminate 1. Gives surface hardness.

  The hard coat layer 3 of the hard coat laminate 1 according to the present embodiment cures a composition containing a curable component and an inorganic filler (hereinafter sometimes referred to as “hard coat layer composition”). It is made of materials.

(2-1) Curing Component As the curable component, an energy ray curable component, a thermosetting component, or the like can be used, but an energy ray curable component is preferable.

  The energy ray curable component is not particularly limited, and may be appropriately selected according to the performance to be imparted to the hard coat layer 3 such as high hardness. Here, the energy ray refers to an electromagnetic wave or a charged particle beam having energy quanta, and specifically includes ultraviolet rays and electron beams. Among energy rays, ultraviolet rays that are easy to handle are particularly preferable.

  Specific energy ray curable components include polyfunctional (meth) acrylate monomers, (meth) acrylate prepolymers, energy ray curable polymers, etc., among which polyfunctional (meth) acrylates. It is preferable that it is a system monomer and / or a (meth) acrylate system prepolymer. The polyfunctional (meth) acrylate monomer and the (meth) acrylate prepolymer may be used alone or in combination. In the present specification, (meth) acrylate means both acrylate and methacrylate. The same applies to other similar terms.

  Examples of the multifunctional (meth) acrylate monomer include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and polyethylene glycol diene. (Meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate phosphoric acid, allylation Cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentae Thritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol Examples include polyfunctional (meth) acrylates such as 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 type.

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

  Examples of the polyester acrylate-based prepolymer include esterification of a hydroxyl group of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid, It can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding alkylene oxide to carboxylic acid with (meth) acrylic acid.

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

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

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

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

  When a polymer having energy beam curable properties is used as the energy beam curable component, the polymer may be, for example, a (meth) acrylate copolymer having an energy beam curable group in the side chain (hereinafter referred to as “energy beam curable”). (Meth) acrylic acid ester copolymer (A) ”). The energy ray-curable (meth) acrylic acid ester copolymer (A) includes an acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound having a substituent bonded to the functional group. Those obtained by reacting with (a2) are preferred.

  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 in the acrylic copolymer (a1) as a structural unit is a molecule containing 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. The monomer contained therein, preferably a hydroxyl group-containing unsaturated compound or a carboxyl group-containing unsaturated compound.

  More specific examples of such functional group-containing monomers include hydroxyl group-containing compounds such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl acrylate. Examples include carboxyl group-containing compounds such as acrylate, 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, and an alkyl group having 1 to 18 carbon atoms (meta ) Acrylic acid alkyl esters are used. Among these, particularly preferably, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate 2-ethylhexyl (meth) acrylate or the like is used.

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

  The acrylic copolymer (a1) can be obtained by copolymerizing a functional group-containing monomer as described above with a (meth) acrylic acid ester monomer or a derivative thereof in a conventional manner. Vinyl formate, vinyl acetate, styrene and the like may be copolymerized in a small amount (for example, 10% by mass or less, preferably 5% by mass or less).

  The substituent which an unsaturated group containing compound (a2) has can be suitably selected according to the kind of functional group of the functional group containing monomer unit which an acrylic copolymer (a1) has. For example, when the functional group is a hydroxyl group, an amino group or a substituted amino group, the substituent is preferably an isocyanate group or an epoxy group. When the functional group is a carboxyl group, the substituent is an aziridinyl group, an epoxy group or an oxazoline group. Preferably, when the functional group is an epoxy group, the substituent is preferably an amino group, a carboxyl group or an aziridinyl group. One such substituent is included in 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 unsaturated group-containing compound (a2) include, for example, acryloyloxyethyl isocyanate, methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate; Alternatively, an acryloyl monoisocyanate compound obtained by reacting a polyisocyanate compound with hydroxyethyl (meth) acrylate; an acryloyl monoisocyanate obtained by reacting a diisocyanate compound or polyisocyanate compound with a polyol compound and hydroxyethyl (meth) acrylate Compound: Glycidyl (meth) acrylate; (meth) acrylic acid, 2- (1-aziridinyl) ethyl (meth) T) Acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline and the like.

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

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

  In addition, when a thermosetting component is used as the curable component, usable thermosetting components include epoxy resins, polyimide resins, phenolic resins, silicone resins, cyanate resins, bismaleimide triazine resins, allyls. Polyphenylene ether resins (thermosetting PPE), formaldehyde resins, unsaturated polyesters or copolymers thereof, among which epoxy resins are preferred.

  The curable component constituting the hard coat layer 3 of the present embodiment preferably has a glass transition point after curing of 130 ° C. or higher, more preferably 150 ° C. or higher, and no glass transition point is observed. It is particularly preferred. Here, in the manufacture of the touch panel, a process of heating the hard coat laminate 1 may be included. In this case, thermal contraction of the hard coat laminate 1 becomes a problem, but the glass transition point satisfies the above conditions. By using the curable component to be filled, the hard coat layer 3 becomes excellent in heat resistance, and excellent heat resistance can be imparted to the hard coat laminate 1.

(2-2) Inorganic filler The composition for hard-coat layers which comprises the hard-coat layer 3 of this embodiment contains an inorganic filler in addition to the sclerosing | hardenable component mentioned above. By including 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, zirconium oxide, beads spheroidized from these, single crystal fibers, glass fibers, and the like. 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 optical transparency, it can be suitably used when the hard coat laminate 1 according to this embodiment is used for optical applications.

  The inorganic filler is preferably surface-modified. An example of such a particularly preferred inorganic filler is reactive silica.

  In this specification, “reactive silica” refers to silica fine particles whose surface is 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 are usually silica having an average particle size of about 0.5 to 500 nm, preferably an average particle size of 1 to 200 nm. It can be obtained by reacting a silanol group on the surface of the fine particle with 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.

（式中、Ｒ^１は水素原子またはメチル基、Ｒ^２はハロゲン原子、

で示される基である。）
で表される化合物等が好ましく用いられる。As an energy ray-curable unsaturated group-containing organic compound having a functional group capable of reacting with a silanol group, for example, the general formula (I)

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a halogen atom,

It is group shown by these. )
A compound represented by the formula is preferably used.

  Examples of such compounds include (meth) acrylic acid, (meth) acrylic acid chloride, (meth) acryloyloxyethyl isocyanate, glycidyl (meth) acrylate, 2,3-iminopropyl (meth) acrylate, (meth ) (Meth) acrylic acid derivatives such as 2-hydroxyethyl acrylate and acryloyloxypropyltrimethoxysilane can be used. These (meth) acrylic acid derivatives may be used individually by 1 type, and may be used in combination of 2 or more type.

  Such reactive silica (silica fine particles surface-modified with an organic compound having an energy ray-curable unsaturated group), the above-mentioned polyfunctional (meth) acrylate monomer and / or (meth) acrylate prepolymer, As the organic-inorganic hybrid material containing, for example, trade names “OPSTAR Z7530”, “OPSTAR Z7524”, “OPSTAR TU4086”, “OPSTAR Z7537” (manufactured by JSR Corporation) and the like can be used.

  The inorganic filler used in the present embodiment preferably has an average particle size of 1 to 200 nm, particularly preferably 10 to 200 nm, and further preferably 20 to 200 nm. When the average particle size of the inorganic filler is 1 nm or more, the hard coat layer 3 obtained by curing the composition for hard coat layer has higher surface hardness. Further, when the average particle size of the inorganic filler is 200 nm or less, light scattering hardly occurs in the obtained hard coat layer 3 and the transparency of the hard coat layer 3 is increased. Therefore, by using such a hard coat layer 3 together with the transparent resin film described above as the base sheet 2, the hard coat laminate 1 according to the present embodiment becomes highly transparent, particularly for optical applications. It can be used suitably. In addition, the average particle diameter of an inorganic filler shall be measured by the zeta potential measuring 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 70% by volume with respect to the hard coat layer 3. % Is more preferable, and 45 to 65% by volume is most preferable. The surface hardness given to the hard-coat layer 3 becomes higher because content of an inorganic filler is 10 volume% or more. On the other hand, layer formation using the composition for hard-coat layers becomes easy because content of an inorganic filler is 85 volume% or less.

  In addition, content of the inorganic filler in this specification shall be calculated | required as follows. The organic component is combusted according to JIS 7250-1, the mass% of the inorganic filler is determined from the obtained ash, and the true density of the inorganic filler is determined according to JIS Z8807. Thereafter, the density of the heat-resistant layer 3 is obtained from JIS Z8807, and the volume% of the inorganic filler is obtained from the measured values of the mass% of the inorganic filler, the true density of the inorganic filler, and the density of the heat-resistant layer 3.

(2-3) Other components The composition for hard-coat layers which comprises the hard-coat layer 3 of this embodiment may contain various additives other than the sclerosing | hardenable component and inorganic filler which were mentioned above. As various additives, for example, photopolymerization initiator, ultraviolet absorber, antioxidant, light stabilizer, antistatic agent, silane coupling agent, anti-aging agent, thermal polymerization inhibitor, colorant, surfactant, Examples include storage stabilizers, plasticizers, lubricants, antifoaming agents, organic fillers, wettability improvers, and coating surface improvers.

  Examples of the photopolymerization initiator include 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 phenyl ketone, 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′-diethylaminobenzof Non, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2 , 4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, and the like. These may be used individually by 1 type and may be used in combination of 2 or more type. Content of the photoinitiator in the composition for hard-coat layers is normally chosen in the range of 0.2-20 mass parts with respect to 100 mass parts of energy-beam curable components.

(2-4) Physical properties of hard coat layer The thickness of the hard coat layer 3 is 20 to 50 µm, preferably 25 to 50 µm. Sufficient surface hardness is provided to the hard-coat laminated body 1 which concerns on this embodiment because the thickness of the hard-coat layer 3 is 20 micrometers or more. 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 easy to handle, and the hard coat laminate 1 becomes unnecessarily thick and the manufacturing cost increases. Can be prevented.

  Moreover, in the hard-coat laminated body 1 of this embodiment, the ratio of the thickness of the hard-coat layer 3 with respect to the thickness of the base material sheet 2 is 0.2-2, Preferably it is 0.25-1.5. Yes, particularly preferably 0.25 to 1, more preferably 0.5 to 1. Sufficient surface hardness is provided to the hard-coat laminated body 1 which concerns on this embodiment because the ratio of the thickness of the hard-coat layer 3 with respect to the thickness of the base material sheet 2 is 0.2 or more. On the other hand, when the thickness ratio is 2 or less, the hard coat laminate 1 is excellent in bending resistance and easy to handle.

  The pencil hardness measured according to JIS K5600-5-4 of the hard coat layer 3 is preferably 5H or more, particularly preferably 6H or more, and further preferably 8H or more. The hard coat laminate 1 that satisfies the requirements of the hard coat layer 3 has a very high surface hardness and is excellent in scratch resistance.

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

  The curl suppressing 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, sometimes referred to as “curl suppressing layer composition”). It will be.

  As the curable component of the curl suppressing layer composition, a component corresponding to the performance to be imparted to the curl suppressing layer 4 may be appropriately selected. It is preferable to select a curable component having a curing shrinkage ratio of 5%. As a specific curable component, the same components as those used in the hard coat layer composition described above can be used.

  Moreover, it is preferable that the composition for curl suppression layers contains an inorganic filler other than a sclerosing | hardenable component. Here, the inorganic filler used in the curl suppression layer composition is preferably the same as that used in the hard coat layer composition, and the content of the inorganic filler in the curl suppression layer composition is The hard coat layer composition is preferably the same level. By including the inorganic filler in this manner, the curling suppression layer 4 and the hard coat layer 3 have the same shrinkage in curing and shrinkage in the hard coat layer 3, and the curling of the hard coat laminate 1 is more effective. Is suppressed.

  Furthermore, the composition for curl suppression layers may contain various additives in addition to the components described above. As various additives, the same additives as those used in the hard coat layer composition described above can be used.

  The curl-suppressing layer composition is preferably the same as the hard coat layer composition described above. By making the composition for curl suppression layer and the composition for hard coat layer the same, the cure shrinkage of curl restraint layer 4 and the cure shrinkage of hard coat layer 3 become the same, and the curl of hard coat laminate 1 is the same. Is suppressed more effectively.

  In the hard coat laminate 1 of the present embodiment, the ratio of the thickness of the curl suppression layer 4 to the thickness of the hard coat layer 3 is 0.2 to 2, preferably 0.2 to 1, particularly preferably. Is 0.3 to 0.8, more preferably 0.5 to 0.8. Since the ratio of the thickness of the curl suppression layer 4 to the thickness of the hard coat layer 3 is 0.2 to 2, the cure shrinkage due to the hard coat layer 3 and the cure shrinkage due to the curl suppression layer 4 are offset. Curling of the hard coat laminate 1 according to the 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, further preferably 20 to 50 μm, and preferably 25 to 50 μm. Is most preferred. When the thickness of the curl suppression layer 4 is in the above range, the ratio of the thickness of the curl suppression layer 4 to the thickness of the hard coat layer 3 easily satisfies the above-described conditions, and the hard coat laminate according to the present embodiment. 1 curl is more effectively suppressed.

(4) Physical Properties of Hard Coat Laminate The hard coat laminate 1 according to the present embodiment preferably has a total height of warp at the four corners of 5 cm or less in the dimensions of 10 cm in length and 10 cm in width. More preferably, it is more preferably 2 cm or less, and most preferably 1 cm or less. The hard coat laminate 1 satisfying such a condition is one in which warpage (curling) is suppressed. In addition, the detail of the specific measuring method is shown in the test example mentioned later.

  In addition, the hard coat laminate 1 according to the present embodiment preferably has a minimum mandrel diameter of 32 mm or less at which no cracking occurs in a flexural resistance test by a cylindrical mandrel method according to JIS K5600-5-1. 25 mm or less is more preferable, and 20 mm or less is particularly preferable. The hard coat laminate 1 satisfying such a condition is not easily cracked or peeled off even when it is wound on or taken out from the winding body, and has excellent bending resistance and is easy to handle. become.

  The haze value of the hard coat laminate 1 according to this embodiment is preferably 3.0% or less, more preferably 1.0% or less, and particularly preferably 0.8% or less, More preferably, it is 0.7% or less. When the haze value is 3.0% or less, the transparency is high, and the hard coat laminate 1 according to this embodiment is suitable for optical use. The haze value is a value measured according to JIS K7136-2000, using a haze meter “NDH5000” manufactured by Nippon Denshoku Industries Co., Ltd.

(5) Manufacturing method of hard coat laminated body 1 The hard coat laminated body 1 which concerns on this embodiment is a curl on the other surface and the composition for hard-coat layers on the one surface of the base material sheet 2 mentioned above, for example. The composition for suppressing layer is applied or bonded, respectively, and cured to form the hard coat layer 3 and the curl suppressing layer 4. Hereinafter, the case where the composition for hard-coat layers and the composition for curl suppression layers contain an energy-beam curable component as a curable component is demonstrated. In addition, since the layer of the composition for hard-coat layers and the composition for curl suppression layers before hardening is fundamentally comprised by the coating film, it is mainly called "coating film" below. However, the present invention is not limited to this.

  Specific methods for producing the hard coat laminate 1 according to the present embodiment include the following two methods, but are not limited to these methods.

  The first method is a coating film of a composition for a hard coat layer applied or bonded to one surface of the substrate sheet 2 and a curl suppression layer applied or bonded to the other surface of the substrate sheet 2. This is a method in which the coating film of the composition layer is cured at once to form the hard coat layer 3 and the curl suppression layer 4, respectively. As an example, first, a first coating film (a layer that becomes the hard coat layer 3 after curing) made of the hard coat layer composition is formed on one surface of the base sheet 2. By further laminating a cover sheet on the surface opposite to the base material sheet 2, a laminate composed of the base material 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 with the cover sheet may be bonded to one surface of the base sheet 2. In addition, as a cover sheet, what was illustrated as a resin film above can be used.

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

  Subsequently, on the other surface of the base material sheet 2 in the laminate (the surface on which the base material sheet 2 is exposed), a second coating film (curling suppression layer 4 after curing) And a cover sheet is further laminated on the surface of the second coating film opposite to the base sheet 2 (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 with the cover sheet may be bonded to the other surface of the base sheet 2.

  The second coating film comprising the curl-suppressing layer composition is prepared by preparing a coating agent containing an energy ray-curable component and other materials constituting the curl-suppressing layer composition and, if desired, a solvent. It forms by apply | coating to the base material sheet 2 or a cover sheet, and making it dry. The 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 hard coat layer.

  For the hard coat layer, the laminate comprising the obtained cover sheet / first coating film / substrate sheet 2 / second coating film / cover sheet is irradiated with energy rays from one or both main surfaces. The first coating film made of the composition and the second coating film made of the composition for curl suppression layer are cured to form a hard coat layer 3 and a curl suppression layer 4, respectively.

Curing of the first and second coating films (formation of the hard coat layer 3 and the curl suppression layer 4) is performed by irradiating these coating films with active energy rays such as ultraviolet rays and electron beams. UV irradiation, high-pressure mercury lamp, a fusion H lamp, can be carried out by a xenon lamp or the like, the dose of ultraviolet ray is illuminance 50~1000mW / cm ^2, about the amount of light 50~1000mJ / cm ² is preferred. 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 hard coat laminate 1 according to the present embodiment is obtained in a state where the cover sheet is laminated on the outer side of the hard coat layer 3 and the cover sheet is laminated on the outer side of the curl suppression layer 4. be able to.

  In the above-described method, the hard coat layer composition and the curl suppression layer composition may be interchanged. That is, a first coating film composed of the composition for curl suppression layer is formed first, then a second coating film composed of the composition for hard coat layer is formed, and then these are cured to hard coat lamination. The body 1 may be produced.

  Here, the cover sheet is used for the purpose of, for example, supporting the laminate in the production process and blocking oxygen in the air that inhibits the energy ray curing reaction from the coating film of the hard coat layer composition, It is removed when the hard coat laminate 1 is used. Note that the cover sheet on the second coating film side can be omitted, and in that case, it is preferable to perform the curing process in an atmosphere having a low oxygen concentration (for example, in a nitrogen atmosphere).

  The second method is a composition for a hard coat layer composition applied or bonded to one surface of the substrate sheet 2 and a curl suppression layer composition applied or bonded to the other surface of the substrate sheet 2. In this method, the coating film of the product is cured in separate steps to form the hard coat layer 3 and the curl suppression layer 4 respectively.

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

  Then, the curl suppression layer 4 is formed in the other surface (surface in which the base material sheet 2 is exposed) of the base material sheet 2 as a 2nd process with respect to the obtained laminated body. Specifically, the second coating film and the cover sheet made of the curl suppressing layer composition are laminated on the surface of the laminate on which the hard coat layer 3 is formed, where the base sheet 2 is exposed. A 2nd coating film may be directly apply | coated and formed on the base material sheet 2, and what was apply | coated and formed on the cover sheet may be bonded to the base material sheet 2. FIG.

  The obtained laminate is irradiated with energy rays from one or both main surface sides to cure the second coating film composed of the curl suppression layer composition, thereby forming the curl suppression layer 4. Thereby, the hard coat laminated body 1 which concerns on this embodiment can be obtained in the state by which the cover sheet was laminated | stacked further on the outer side of the hard-coat layer 3, and the cover sheet was laminated | stacked further on the outer side of the curl suppression layer 4. .

  In the second method, the hard coat layer composition and the curl suppression layer composition may be interchanged. That is, in the first step, a first coating film made of the curl suppression layer composition is formed on one surface of the base sheet 2, and the first coating film is cured to form the curl suppression layer 4. . Subsequently, in the second step, a second coating film made of the composition for hard coat layer is formed on the other surface of the substrate sheet 2 (the surface on which the substrate sheet 2 is exposed) and cured. Let it be a hard coat layer. In this way, the hard coat laminate 1 may be produced.

  In the second method, one or both of the two cover sheets can be omitted. In that case, the curing process can be performed in an atmosphere having a low oxygen concentration (for example, in a nitrogen atmosphere). preferable.

  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 the hard coat layer composition is particularly preferable in the first method. The method of forming the 1st coating film and the 2nd coating film which consists of a composition for curl suppression layers, and irradiating an energy ray and forming the hard-coat layer 3 and the curl suppression layer 4 is preferable.

(6) Use of Hard Coat Laminate 1 The use of the hard coat laminate 1 according to the present embodiment can be preferably used for applications that require both high surface hardness and curl suppression. In particular, when the hard coat laminate 1 has transparency such as a small haze value, an optical member such as a liquid crystal display (LCD), a plasma display (PDP), an organic EL display (OELD), a touch panel, etc. It can be used as the surface layer of various displays. Especially, since the hard coat laminated body 1 which concerns on this embodiment has high surface hardness, it is especially suitable as a surface layer of a touch panel.

  The hard coat laminate 1 according to this embodiment may be laminated with an adhesive layer, a barrier layer, a conductive layer, a low reflection layer, an easy print layer, an antifouling layer, and the like.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

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

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
Hard coat layer composition (manufactured by JSR, trade name “OPSTAR Z7530”, dipentaerythritol hexaacrylate (density: 1.25 g / cm ³ ) as an energy ray-curable component and reactive silica (density) : 2.1 g / cm ³ ) at a mass ratio of 40:60, inorganic filler content: 49% by volume, photopolymerization initiator: 3% by mass, solid content concentration: 73% by mass, solvent: methyl ethyl ketone) , Coated on one side of a polyethylene terephthalate (PET) film (trade name “Cosmo Shine PET25A4300”, thickness: 25 μm, manufactured by Toyobo Co., Ltd.) as a base sheet with a die coater so that the thickness after drying is 25 μm Then, it processed at 80 degreeC for 1 minute, and formed the coating film of the composition for hard-coat layers. Next, a cover sheet (trade name “Cosmo Shine PET38A4100” manufactured by Toyobo Co., Ltd.) was bonded to the obtained coating film, and then ultraviolet (UV) irradiation (illuminance: 230 mW / cm) from the cover sheet side of the obtained laminate. ² , light quantity: 190 mJ / cm ² ), and the hard coat layer composition was cured to form a hard coat layer (thickness: 25 μm).

Subsequently, a curl-suppressing layer composition (manufactured by JSR, trade name “OPSTAR Z7530”, as described above) is formed on the surface of the obtained laminate to which the cover sheet is not bonded (the surface on which the base sheet is exposed). The same coating composition as the hard coat layer) was applied with a die coater so that the thickness after drying was 25 μm, and then treated at 80 ° C. for 1 minute to form a coating film of the curl suppression layer composition. did. Next, after a cover sheet (trade name “Cosmo Shine PET38A4300” manufactured by Toyobo Co., Ltd.) was bonded to the obtained coating film, UV irradiation (illuminance: 230 mW / cm ² , from the cover sheet side of the obtained laminate was performed. Light amount: 190 mJ / cm ² ) to cure the curl suppression layer composition to form a curl suppression layer (thickness: 25 μm). Thus, a laminate comprising a cover sheet / hard coat layer / base sheet / curl suppression layer / cover sheet, that is, a hard coat laminate in which the cover sheet is laminated on the outside of the hard coat layer and the curl suppression layer. Got the body.

[Examples 2 to 8, Comparative Examples 1 to 4]
Similar to Example 1 except that a PET film having the thickness shown in Table 1 is used as the base sheet, and the thickness of the hard coat layer and the thickness of the curl suppressing layer are changed to the values shown in Table 1. Thus, a hard coat laminate was produced.

Example 9
As a composition for curl suppression layer, 100 parts by mass of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) as an energy ray-curable component, and hydroxycyclohexyl phenyl ketone (manufactured by BASF, as a photopolymerization initiator) “Irgacure 184”) Example with the exception of using a mixture with 2.5 parts by weight, using a PET film with a thickness of 50 μm as the base sheet, and changing the thickness of the curl suppression layer to 5 μm. In the same manner as in Example 1, a hard coat laminate was produced.

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

[Test Example 1] (Measurement of pencil hardness)
Two cover sheets were peeled from the hard coat laminates obtained in Examples and Comparative Examples, and the hard coat layer surface was exposed and fixed on a glass plate. About the exposed hard-coat surface, according to JISK5600-5-4, the pencil hardness was measured using the pencil scratch hardness tester (The product name "No.553-M" by Yasuda Seiki Seisakusyo Co., Ltd.). The scratching speed was 1 mm / second. The results are shown in Table 1. Moreover, the thing whose pencil hardness is 5H or more was evaluated as favorable ((circle)) and 4H or less as bad (x). The results are shown in Table 1.

[Test Example 2] (Measurement of curl amount)
The hard coat laminates obtained in the examples and comparative examples were cut so as 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 vertical distances (cm) from the table surface at the four corners in an atmosphere of 23 ° C. and 50% RH, and the total value of the four distances was defined as the curl amount (cm). The results are shown in Table 1. Moreover, the curl amount of 5 cm or less was evaluated as good (◯), and the curl amount exceeding 5 cm was evaluated as bad (×). The results are shown in Table 1.

  As is clear from Table 1, the hard coat laminates obtained in the examples had high surface hardness and curling was suppressed. On the other hand, the hard coat laminates obtained in Comparative Examples 1 to 3 were inferior in surface hardness, and the hard coat laminates obtained in Comparative Examples 4 to 5 had a remarkable degree of curling. Furthermore, the hard coat laminate obtained in Comparative Example 6 was inferior in surface hardness and had a remarkable degree of curling.

  The hard coat laminated body of this invention is used suitably for the surface layer protective sheet of various displays, such as a liquid crystal display (LCD), a plasma display (PDP), an organic electroluminescent display (OELD), a touch panel, for example.

DESCRIPTION OF SYMBOLS 1 ... Hard-coat laminated body 2 ... Base material sheet 3 ... Hard-coat layer 4 ... Curl suppression layer

Claims (7)

A hard coat laminate comprising a base sheet, a hard coat layer laminated on one main surface side of the base sheet, and a curl suppression layer laminated on the other main surface side of the base sheet. There,
The hard coat layer is made of a material obtained by curing a composition containing a curable component and an inorganic filler,
The content of the inorganic filler in the hard coat layer is 40 to 85 vol% with respect to the hard coat layer,
The curl suppressing layer is made of a material obtained by curing a composition containing a curable component and an inorganic filler,
The base sheet has a thickness of 25 to 100 μm,
The hard coat layer has a thickness of 20 to 50 μm,
The ratio of the thickness of the hard coat layer to the thickness of the base sheet is 0.2-2.
The ratio of the thickness of the curl suppressing layer to the thickness of the hard coat layer is 0.2 to 2, wherein the hard coat laminate is characterized in that   The hard coat laminate according to claim 1, wherein the hard coat layer has a pencil hardness measured in accordance with JIS K5600-5-4 of 5H or more.   The hard coat laminate according to claim 1 or 2, wherein the composition constituting the curl suppression layer is the same as the composition constituting the hard coat layer. Wherein the inorganic filler in the composition for a hard coat layer, the hard coat laminate according to claim 1, characterized in that the reactive silica.   The hard coat laminate according to any one of claims 1 to 4, wherein the total height of warp at the four corners is 5 cm or less in the dimensions of 10 cm in length and 10 cm in width.   6. The curable component in the hard coat layer composition and the curable component in the curl suppression layer composition are energy ray curable components. The hard coat laminate according to one item. A method for producing the hard coat laminate according to claim 6, comprising:
A first layer made of the composition for the hard coat layer was laminated on one main surface side of the base sheet, and a cover sheet was laminated on the side opposite to the base sheet side of the first layer. Make a laminate,
Forming a second layer made of the composition for curl suppression layer on the other main surface side of the base sheet in the laminate,
A method for producing a hard coat laminate, wherein the first layer and the second layer are cured by energy ray irradiation to form a hard coat layer and a curl suppression layer.

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