JP6939134B2 - Hard coat sheet and packaging case for case assembly - Google Patents

Description

The present invention relates to a hard coat sheet, and more particularly to a packaging case made of a plastic sheet and a hard coat sheet for assembling a case for assembling the packaging case.

Conventionally, plastic sheets (for example, polypropylene sheets (hereinafter, may be referred to as PP sheets), unstretched polyester sheets, etc.) have excellent transparency, mechanical strength, and the like, and have been used for packaging cases.

In the packaging case, there is a problem that the surface of the case is rubbed and scratches occur when the packaging cases come into contact with each other, such as during transportation. Therefore, with respect to the plastic sheet constituting the packaging case, in order to improve the slipperiness and scratch resistance of the sheet surface, a radiation-curable silicone resin is added to the polyfunctional acrylate to achieve both the slipperiness and the scratch resistance. Proposals have been made (see, for example, Patent Document 1 and Patent Document 2).

On the other hand, in the case of a packaging case made of PP sheet, when UV offset printing, automatic punching, and automatic glue pasting (using hot melt or primer treatment and instant adhesive) are performed on the packaging case used for the clear case, etc., the PP sheet A treatment such as aging may be performed so that the antistatic agent, the slip agent, etc., which are compounding agents (kneading), bleed out to the sheet surface to improve the antistatic property and the slip property. For example, after the production of the PP sheet, aging (curing) is performed at 40 to 50 ° C. for 2 to 3 days, and then the PP sheet is left to stand for 2 to 3 weeks for additional aging. Express performance. Further, in order to further improve the slipperiness, powder such as cornstarch powder is made into a mist and sprayed on both the front and back surfaces of the sheet. Although it is performed separately from the antistatic agent, the slip agent, and the embossing of the surface, it is considered that the improvement of the slip property by these treatments may be insufficient (for example, Patent Documents). 3. See Patent Document 4).

Japanese Unexamined Patent Publication No. 2002-322301 Japanese Unexamined Patent Publication No. 11-29720 Japanese Unexamined Patent Publication No. 2006-89652 Japanese Unexamined Patent Publication No. 6-246829

However, according to Patent Document 1, when a silicone-treated release film is attached to a shelf board for use in order to improve the slipperiness of the packaging case, the slipperiness is good but the scratch resistance is weak. Therefore, there was a problem that it was scratched and it was difficult to use it for a long period of time. Further, in order to improve the scratch resistance, it is conceivable to use a hard coat sheet, but the slipperiness is often insufficient.
Patent Document 2 is a hard coat sheet having a structure in which a radiation-curable silicone resin is added to a polyfunctional acrylate and a hard coat layer is provided, which proposes to achieve both slipperiness and scratch resistance. Needed to be further improved in slipperiness.
Further, in the plastic sheets used for the packaging cases of Patent Documents 3 and 4, further improvement in slipperiness and scratch resistance has been desired.

An object of the present invention is to provide a hard coat sheet for assembling a case having excellent transparency, slipperiness, scratch resistance, and bending property, and a packaging case having excellent transparency, slipperiness, and scratch resistance. Is to be.

That is, the gist of the present invention is as follows.
<1> Photocurability containing at least one selected from the group consisting of polyfunctional (meth) acrylate, urethane (meth) acrylate, photopolymerization initiator, and fluorine compound and silicone compound on at least one side of the plastic sheet. A hard coat sheet for assembling a case, in which a photocurable resin layer having a thickness of 0.1 to 0.8 μm obtained by curing the composition is laminated.
<2> The hard coat sheet for case assembly according to <1>, wherein the polyfunctional (meth) acrylate contains at least one selected from the group consisting of pentaerythritol triacrylate and pentaerythritol tetraacrylate.
<3> The hard coat sheet for assembling a case according to <1> or <2>, wherein the plastic sheet is an unstretched polyester sheet or a polypropylene sheet.
<4> The unstretched polyester sheet is at least two copolymerized polyester layers, and the polyester layer on the photocurable resin layer side has a structure derived from terephthalic acid as a dicarboxylic acid component and ethylene as a diol component. The hard coat sheet for case assembly according to <3>, which comprises a polyester having a structure derived from glycol and a structure derived from 1,4-cyclohexanedimethanol.
<5> A packaging case using the hard coat sheet for assembling the case according to any one of <1> to <4>.

According to the present invention, a hard coat sheet for assembling a case having excellent transparency, slipperiness, scratch resistance, and bending property, and a packaging case having excellent transparency, slipperiness, and scratch resistance are provided. Can be done.

<Hard coat sheet>
The hard coat sheet of the present invention includes a plastic sheet and a photocurable resin layer having a thickness of 0.1 to 0.8 μm, and a case assembly hardware in which a photocurable resin layer is laminated on at least one surface of the plastic sheet. It is a coat sheet. Further, the photocurable resin layer is at least one selected from the group consisting of a polyfunctional (meth) acrylate, a urethane (meth) acrylate, a photopolymerization initiator, and a fluorine compound and a silicone compound on at least one side of the plastic sheet. It is a layer which hardened the photocurable composition containing.
Since the photocurable composition containing the above components is excellent in curability, it is excellent in slipperiness and scratch resistance. Further, since it is excellent in curability, it can be cured even if the content of the component of the photocurable composition is small, and the layer thickness of the photocurable resin layer can be made into a thin film of 0.1 to 0.8 μm, which is transparent. It has excellent properties and can be bent.
Hereinafter, the hard coat sheet for assembling the case may be simply referred to as a hard coat sheet.

[Plastic sheet]
The material of the plastic sheet used as the base material of the hard coat sheet is not particularly limited, but from the viewpoint of good folding resistance, biological resins such as polyester, polypropylene (PP), polyethylene, polycarbonate, and polylactic acid, Other resin alone or a composite thereof can be used.
Among the above, polyester sheets and polypropylene sheets are preferable because they have good transparency and high rigidity. Further, since the polyester sheet has better transparency and is unstretched, it does not depend on the direction of the sheet and has high strength. Therefore, it is preferable that the polyester sheet is an unstretched polyester sheet. Therefore, the plastic sheet is more preferably an unstretched polyester sheet or a polypropylene sheet.

The unstretched polyester sheet is at least two polyester layers, and the polyester layer on the photocurable resin layer side has a structure derived from terephthalic acid as a dicarboxylic acid component, a structure derived from ethylene glycol as a diol component, and 1, It preferably contains a polyester having a structure derived from 4-cyclohexanedimethanol.
The unstretched polyester sheet is more preferably a laminate composed of at least three polyester layers, that is, a substrate layer (A) and a surface layer (B).
The surface layer (B) refers to a polyester layer including an exposed surface of a laminated body, and the substrate layer (A) refers to an intermediate layer sandwiched between two surface layers (B). The substrate layer (A) may be one layer or two or more layers.

As described above, in the hard coat sheet of the present invention, a photocurable resin layer is laminated on at least one side of the plastic sheet. When the photocurable resin layer is laminated on only one side of the plastic sheet, the surface layer on the photocurable resin layer side is referred to as a "surface layer (front)" for convenience, and is not adjacent to the photocurable resin layer. The side surface layer is referred to as a "surface layer (back)". The layer structure is represented by, for example, a surface layer (front) / a substrate layer (A) / a surface layer (back).
The thickness of the base layer (A) is as a whole, that is, if the base layer (A) is one layer, it is the thickness of one layer, and if the base layer (A) is three layers, it is the thickness of all three layers. It is preferably 100 to 300 μm, more preferably 150 to 250 μm.
The layer thickness of the surface layer (B) is preferably 10 to 40 μm, more preferably 20 to 30 μm per layer.

The polyester resin constituting the base layer (A) is preferably a polyester resin containing polyethylene terephthalate, which is a polycondensation of terephthalic acid and ethylene glycol, as a main component. That is, the copolymer of ethylene terephthalate or 60 mol% or more, preferably 90 mol% or more of the dicarboxylic acid is terephthalic acid, and 60 mol% or more, preferably 90 mol% or more of the diol component is ethylene glycol. It consists of a coalescence or a mixture of such various polyester resins.
In addition, terephthalic acid and ethylene glycol as a raw material for producing a polyester resin may be an ester-forming derivative (for example, dimethyl terephthalate), and the same applies to the copolymerization component described later.

When the polyester resin is a copolymer, specific examples of copolymerization components other than terephthalic acid and ethylene glycol include isophthalic acid, phthalic acid, adipic acid, sebacic acid, neopentylic acid, diphenylcarboxylic acid, diphenyl ether dicarboxylic acid, and diphenylsulfone dicarboxylic acid. Examples thereof include dicarboxylic acids such as acids and naphthalenedicarboxylic acids, and diol components such as diethylene glycol, polyalkylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, hexamethylene glycol, trimethylene glycol, propylene glycol and styrene glycol. ..

The polyester resin containing the above-mentioned copolymer component is easy to form into a sheet, has excellent mechanical strength, rigidity, transparency, bendability, etc., and is a sheet base of a packaging container composed of a highly transparent sheet. Suitable as a material.

The polyester resin constituting the surface layer (B) has a dicarboxylic acid component containing terephthalic acid as a main component and a glycol component composed of 90 to 10 mol% of ethylene glycol and 10 to 90 mol% of 1,4-cyclohexanedimethanol. It is preferable to use a polymerized polyester resin as a main component.
Further, at least one layer of the surface layer on the photocurable resin layer side has a structure derived from terephthalic acid as a dicarboxylic acid component, a structure derived from ethylene glycol as a diol component, and a structure derived from 1,4-cyclohexanedimethanol. It is preferable to include the polyester having. In addition, at least one layer of the surface layer on the photocurable resin layer side means the photocurable resin layer when the photocurable resin layer is laminated only on one side of the unstretched polyester sheet, and is photocured. When the sex resin layer is laminated on both sides of the unstretched polyester sheet, it means one layer or both layers (preferably both layers) of the two surface layers.
When an unstretched polyester sheet is formed by using a copolymerized polyester of these two types of glycol components and a dicarboxylic acid component as a surface layer, a functional layer (for example, a printing layer, a hard coat layer, etc.) is formed on the unstretched polyester sheet. When the above is provided, there is an advantage that the adhesion between the unstretched polyester sheet and the functional layer is improved. Further, since the copolymerized polyester has good solvent resistance, for example, even if a printing layer containing a solvent is processed on the copolymerized polyester layer, the film surface has an advantage that it is difficult to whiten.

The polyester layer constituting the surface layer (B) and the substrate layer (A) preferably has an intrinsic viscosity of 0.4 to 1.1 (d / l) in order to secure the mechanical strength of the sheet itself. .. When the intrinsic viscosity is 0.4 (d / l) or more, the mechanical strength of the final product such as the packaging container formed of the sheet is improved, and the impact strength is excellent especially in a low temperature state, and the packaging container is bent. It is easy to secure the desired flexibility during processing. On the other hand, when the intrinsic viscosity is 1.1 (d / l) or less, the melt moldability for forming a film into a sheet is excellent.
The intrinsic viscosity of the polyester in each layer constituting the unstretched polyester sheet is obtained by precisely weighing 1 g of the polyester from which other polymer components and pigments incompatible with the polyester have been removed, and phenol / tetrachloroethane = 50/50 (weight ratio). ) Is added to dissolve 100 ml of the mixed solvent, and the mixture is measured at 30 ° C. to obtain the substance.

The surface layer (B) may be composed of a polyester resin composition containing inert particles together with the polyester resin. The inert particles are preferably added to such an extent that the transparency is not reduced. Specific examples of such inert particles include inorganic particles such as silica, titanium oxide, calcium carbonate, iron oxide, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, barium sulfate, calcium phosphate, aluminum hydroxide, and the like. Mixtures or inorganic compounds such as talc, clay, wollastonite, kaolin, terephthalic acid salts (Ca salt, Ba salt, Zn salt, Mn salt, etc.), organic compounds with high melting point that can withstand the molding temperature of polyester resin, heat Examples thereof include crosslinked polymers such as curable resins. Among the inert particles, those having a high affinity with the polyester resin are preferable, and silica particles are particularly preferable.

[Photocurable resin layer]
The photocurable resin layer is provided on at least one surface of the plastic sheet surface, and is selected from the group consisting of a polyfunctional (meth) acrylate, a urethane (meth) acrylate, a photopolymerization initiator, a fluorine compound, and a silicone compound. A layer obtained by curing a photocurable composition containing at least one, and having a thickness of 0.1 to 0.8 μm.

From the viewpoint of achieving both high surface hardness and flexibility of the photocurable resin layer, the photocurable composition includes polyfunctional (meth) acrylate, urethane (meth) acrylate, photopolymerization initiator, and fluorine compound and silicone. Contains at least one selected from the group consisting of compounds.

(Polyfunctional (meth) acrylate)
Specific examples of the polyfunctional (meth) acrylate include dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, and ditrimethylol. Propanetetra (meth) acrylate, trimethyl propanetri (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, hexanediol Examples thereof include di (meth) acrylate and neopentyl glycol di (meth) acrylate. Only one kind of these polyfunctional (meth) acrylates may be used, or two or more kinds may be used.
Among the above, the polyfunctional (meth) acrylate preferably contains at least one selected from the group consisting of pentaerythritol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate, and pentaerythritol triacrylate and pentaerythritol. More preferably, it contains at least one selected from the group consisting of tetraacrylates.

(Urethane (meth) acrylate)
Further, the photocurable composition contains, in addition to the polyfunctional (meth) acrylate, urethane (meth) acrylate described below from the viewpoint of widening the adjustment range of the flexibility of the hard coat sheet.
Urethane (meth) acrylate has four or more (meth) acryloyl groups in one molecule obtained by reacting an aliphatic polyisocyanate with a (meth) acrylate having a hydroxyl group. Aliphatic polyisocyanate is a compound in which the moiety other than the isocyanate group is composed of an aliphatic hydrocarbon. Specific examples of this aliphatic polyisocyanate include aliphatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, and lysine triisocyanate; norbornan diisocyanate, isophorone diisocyanate, methylenebis (4-cyclohexylisocyanate), and 1,3-bis (isocyanato). Examples thereof include alicyclic polyisocyanates such as methyl) cyclohexane, 2-methyl-1,3-diisocyanatocyclohexane, and 2-methyl-1,5-diisocyanatocyclohexane.
Among the above, urethane acrylate is used in combination with pentaerythritol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate and urethane acrylate from the viewpoint of achieving both high surface hardness and flexibility of the photocurable resin layer. Is preferable.

The blending ratio of the polyfunctional (meth) acrylate and the urethane (meth) acrylate [polyfunctional (meth) acrylate / urethane (meth) acrylate] is preferably in the range of 90/10 to 10/90 in terms of mass ratio. More preferably, the range is 80/20 to 40/60.

(Photopolymerization initiator)
The photopolymerization initiator is not particularly limited, and examples thereof include a ketone-based photopolymerization initiator and an amine-based photopolymerization initiator.
Above all, from the viewpoint of curability of the photocurable composition, it is preferable to use a ketone-based photopolymerization initiator, and a compound represented by the following formula (I) is more preferable.

In formula (I), R ^{1 to} R ⁷ each independently represent a hydrogen atom, R ⁸ S-, an alkyl group, or an aryl group, and R ⁶ and R ⁷ are bonded to each other to form a ring structure. May be good. R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ⁸ represents a hydrogen atom, an alkyl group, or an aryl group. X ¹ represents a hydroxy group or a tertiary amino group.

In R ^{1 to} R ⁸ , the alkyl group includes a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and n. -Butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, n-octyl group, n-decyl group, n-dodecyl group and the like can be mentioned. The alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms. The alkyl group may further have a substituent.
In R ⁸ S-, when R ⁸ is an alkyl group, ^{it means that R 8} S- is an alkyl thio group, and when R ⁸ is an aryl group ^{, it means that R 8} S- is an aryl thio group. Then, when R ⁸ is a hydrogen atom, ^{it means that R 8} S- is a sulfanyl group.

In R ^{1 to} R ⁸ , examples of the aryl group include an aryl group having 6 to 20 carbon atoms, and examples thereof include a phenyl group and a naphthyl group. The aryl group preferably has 6 to 12 carbon atoms. The aryl group may further have a substituent.

Examples of the substituent that the alkyl group and the aryl group may further have include a hydroxy group, a halogen atom, an alkyl group, an aryl group, a carbonyl group, and a group composed of a combination thereof. The same applies to the substituents that the alkyl group may further have in ^Ra , R ^b , R ^{21 to} R ²⁷ and R ^{31 to} R ³⁵ , which will be described later, and the substituents that the aryl group may further have will be described later. The same applies to R ^{21 to} R ²⁷ and R ^{31 to} R ^35.

R ¹ , R ² , R ⁴ and R ⁵ are each independently preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. It is preferably a hydrogen atom, and more preferably a hydrogen atom.
R ³ is preferably a hydrogen atom, R ⁸ S-, or an alkyl group having 1 to 12 carbon atoms, and more preferably a hydrogen atom or R ⁸ S-.
R ⁸ is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and further preferably an alkyl group having 1 to 3 carbon atoms. preferable.

In X ¹ , the tertiary amino group is represented by ^{−NR a} (R ^{b ), Ra} and R ^b each independently represent an alkyl group, and ^Ra and R ^b are bonded to each other to form a ring structure. It may be formed.
The alkyl groups represented by ^{R a} and R ^b are the same as the alkyl groups represented by ^{R 1 to} R ^7.
R ^a and R ^b are each independently preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.

The compound represented by the formula (I) is preferably a compound represented by the following formula (II-1) or (II-2), and is represented by the formula (II-1) from the viewpoint of curability. It is preferable to use a compound and a compound represented by (II-2).

In formula (II-1), R ^{21 to} R ²⁶ independently represent a hydrogen atom, an alkyl group, or an aryl group, and R ²⁷ represents a hydrogen atom, a hydroxy group, an alkyl group, or an aryl group. X ² represents a nitrogen atom or an oxygen atom.
In formula (II-2), R ^{31 to} R ³⁴ independently represent a hydrogen atom, an alkyl group, or an aryl group, and R ³⁵ represents a hydrogen atom, a hydroxy group, an alkyl group, or an aryl group.

The alkyl and aryl groups represented by ^{R 21 to} R ²⁷ and R ^{31 to} R ³⁵ are the same as the alkyl and aryl groups represented by ^{R 1 to} R ^7.
R ²¹ , R ²² , R ²⁴ and R ²⁵ are each independently preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. It is preferably a hydrogen atom, and more preferably a hydrogen atom.
R ²³ is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms, and further preferably an alkyl group having 1 to 3 carbon atoms.
R ²⁶ and R ²⁷ are preferably hydrogen atoms or alkyl groups having 1 to 12 carbon atoms, more preferably hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, and alkyl groups having 1 to 3 carbon atoms. Is more preferable.
X ² is preferably an oxygen atom.

R ^{31 to} R ³⁴ are each independently preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and are hydrogen atoms. Is even more preferable. R ³⁵ is preferably a hydroxy group.

Examples of the compound represented by the formula (I) include the following compounds (1) to (3). The compound (1) is a compound represented by the formula (II-1), and the compound (2) is a compound represented by the formula (II-2).

Only one type of photopolymerization initiator may be used, or two or more types may be used.
From the viewpoint of enhancing the curability of the photocurable composition, it is preferable to use two or more photopolymerization initiators. The upper limit is not particularly limited, but from the viewpoint of the efficiency of use of the photopolymerization initiator, it is preferably 5 or less, and more preferably 2 to 4 types.

As the photopolymerization initiator, a commercially available photocuring initiator may be used. As specific examples, BASF's Irgacure 184, 1173, 2959, 907, 369E, 127, Darocure 1116, 1173, Lucillin TPO, 8893; UCB's Yubekrill P36; Fratelli Lamberti's Ezacure KIP150, KIP65LT, Examples thereof include KIP100F, KT37, KT55, KTO46, KIP75 / B, benzophenone, and acetophenone.

In addition, a sensitizer may be used in combination with the photocuring initiator, if necessary. Specific examples thereof include aliphatic amines such as n-butylamine, triethylamine, and ethyl p-dimethylaminobenzoate, and aromatic amines.

The content of the photopolymerization initiator in the photocurable composition is in the range of 1 to 10 parts by mass of the photopolymerization initiator with respect to 100 parts by mass of the total of the polyfunctional (meth) acrylate and the urethane (meth) acrylate. It is preferable to have.
When the amount of the photopolymerization initiator is 1 part by mass or more, the desired polymerization initiation effect can be obtained, and when the amount of the photopolymerization initiator is 10 parts by mass or less, yellowing of the photocurable resin layer is suppressed. Can be done. The photocurable initiator and sensitizer are preferably used in a proportion of 20% by mass or less based on the solid content of the photocurable composition.

(Fluorine compound, silicone compound)
By containing one or both of the fluorine compound and the silicone compound in the photocurable composition, when the photocurable composition is applied to the surface of the plastic sheet, the photocurable composition is prevented from repelling, and light is also prevented. The uniformity of the curable composition film can be improved.

The fluorine compound is not particularly limited _{, but a fluorine compound having a fluorinated alkyl group represented by the general formula F (CF 2} ) _n CH ₂ CH _2- (in the formula, n is an integer of 1 to 10) is used. preferable. The fluorinated alkyl group is a perfluoroalkyl group in which all hydrogen atoms in the alkyl group are substituted with fluorine atoms, and a part of hydrogen atoms in the alkyl group is substituted with fluorine atoms (for example, HCF ₂ CF _2). It _{may be either CF 2} CF ₂ -etc.), And it may be either a linear group or a branched group. Further, those containing an oxygen atom in the fluorinated alkyl group (for example, CF _3- (OCF ₂ CF ₂ ) _2-, etc.) may be used. The number of carbon atoms of the fluorinated alkyl group is usually an integer of 1 to 20, preferably an integer of 3 to 12, and more preferably an integer of 6 to 10 from the viewpoint of high effect of surface activity. be. Further, it is preferably a linear perfluoroalkyl group.

Examples of commercially available fluorine-based leveling agents include Mega Fvck series manufactured by DIC (MCF350-5, F445, F444, F455, F178, F470, F475, F479, F477, TF1025, F478, F178K, RS-56, etc. RS-75, RS-78, etc.), TSF series manufactured by Momentive Performance Materials Japan GK, etc. can also be used. Only one kind of these may be used, or two or more kinds may be used.

The silicone compound is preferably a silicone compound having a structure represented by the following formula (i).

In the formula, Ra represents an alkyl group having 1 to 8 carbon atoms or a phenyl group, and Rb represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a polyether-modified group. Each Ra and Rb may be the same or different from each other. Further, m and n are integers.
Examples of the alkyl group represented by Ra include a methyl group and the like.
The alkyl group and alkoxy group represented by Rb may be unsubstituted or substituted with one or more selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxyl group, an acryloyl group and a methacryloyl group. May be.

The silicone compound can be obtained as a commercially available product. For example, as polyether-modified silicone oil, TSF4440, TSF4446, TSF4452, TSF4460 (manufactured by Momentive Performance Chemicals Japan GK), X-22-4952, X-22-4272, KF-6123 (manufactured by Shin-Etsu Chemical Co., Ltd.) ) Etc., various modified silicone oils can be obtained according to the purpose.
Only one kind of these may be used, or two or more kinds may be used.

Commercially available products that can be used as the above-mentioned fluorine compound and silicone compound include, for example, Polyflow KL-401, KL-402, KL-403, KL-404 (all manufactured by Kyoeisha Co., Ltd.); BYK-302, BYK. -307, BYK-325, BYK-331, BYK-333, BYK348, BYK378, BYK-UV-3535, BYK-UV-3530, BYK-UV-3500, BYK-381, BYK-3441 (above, Big Chemie Japan) (Manufactured by Co., Ltd.); DOWN CORNING TORAY8019ADDITIVE, DOWN CORNING TORAY 1313 ANTIFORM EMULSION (all manufactured by Toray Dow Corning Co., Ltd.) and the like are exemplified.
The content (total amount) of the fluorine compound and the silicone compound in the photocurable composition is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the polyfunctional (meth) acrylate, and is 0.01. More preferably, it is ~ 5 parts by mass.

(Inorganic oxide particles)
The photocurable composition may contain inorganic oxide particles in order to improve the hardness of the surface of the photocurable resin layer.
The inorganic oxide particles are, for example, at least one selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, antimony oxide and cerium oxide, preferably. Particles containing at least one oxide as a main component selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide, and titanium oxide are preferable. These may be those surface-treated with a compound having an alkoxy group, a carboxy group, a (meth) acryloyl group, an epoxy group, or the like. The average particle size of the inorganic oxide particles is preferably 5 to 500 nm.
The content of the inorganic oxide particles in the photocurable composition is preferably 1 to 100 parts by mass with respect to 100 parts by mass in total of the polyfunctional (meth) acrylate and the urethane (meth) acrylate. More preferably, it is 5 to 50 parts by mass.

(solvent)
As the photocurable composition, at least one selected from the group consisting of a polyfunctional (meth) acrylate, a urethane (meth) acrylate, a photopolymerization initiator, and a fluorine compound and a silicone compound can be used as needed. It can be prepared by mixing with oxide particles.
A known solvent may be added in the preparation of the photocurable composition, but the solvent is not contained from the viewpoint of enhancing the curability of the photocurable composition and suppressing the influence on the printing layer described later. Is preferable. Specifically, the content of the solvent in the photocurable composition is preferably 5% by mass or less, more preferably 1% by mass or less, and further preferably 0% by mass.
Further, since the photocurable composition does not contain a solvent, the time required for drying and curing the photocurable composition can be shortened, and the productivity of the hard coat sheet can be improved.
In the present invention, the solvent refers to water, an organic compound having no polymerizable functional group and having a molecular weight of 300 or less, and a mixed solution thereof.

[Manufacturing method of hard coat sheet]
The method for producing the hard coat sheet is not particularly limited, and a photocurable composition is applied to one or both sides of the above-mentioned plastic sheet so that the layer thickness after curing is 0.1 to 0.8 μm. By curing the photocurable composition film, a hard coat sheet in which a photocurable resin layer is laminated on a plastic sheet can be produced.
As a method of providing the photocurable composition film on the plastic sheet, conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, and curtain coating can be used. Regarding the coating method, there is an example described in "Coating Method" by Yuji Harasaki, published in 1979.
Further, the photocurable composition film is provided on the plastic sheet by immersing the plastic sheet in the photocurable composition liquid or transferring the photocurable composition film formed on the release sheet to the plastic sheet. May be good.

Further, the photocurable composition-imparted surface of the plastic sheet may be subjected to corona treatment, plasma treatment or the like in advance, or may be provided with a coating layer having functions such as antistatic property and easy adhesiveness. good.

The photocurable composition film formed on the plastic sheet can be dried and cured by irradiating the photocurable composition film with ultraviolet rays to form a photocurable resin layer.
The photocurable composition film may be dried by heating at 80 to 150 ° C. for 15 to 120 seconds. Further, the irradiation condition of ultraviolet irradiation may be 10 to 800 W / cm. A high-pressure mercury lamp can be used for ultraviolet irradiation.

The thickness of the plastic sheet is preferably 0.1 to 1.0 mm, more preferably 0.2 to 0.6 mm, in consideration of folding resistance and rigidity.
When the sheet thickness is 0.1 mm or more, it is hard to be damaged when the hard coat sheet is bent, and when the hard coat is 1.0 mm or less, when the hard coat is used for the packaging case, during the bending process in the packaging case manufacturing process. The pressure required for processing is unlikely to increase excessively.

When the hard coat sheet is used for a packaging case, a ruled line is formed on the surface of the hard coat sheet through a ruled line processing process. At that time, the type of the folding ruled line, which is a polygonal line, is not particularly limited. As a specific example, a ruled line with intermittent slits such as perforations, a concave hole-shaped push ruled line, a V-shaped or U-shaped ruled line with intermittent or continuous trapezoidal grooves, and a two-step groove inside the groove. Examples thereof include a two-step ruled line and a ruled line in which streaky grooves are arranged in parallel in close proximity to each other. In addition, the type of ruled line can be appropriately selected according to the dimensions of the case, the material of the plastic sheet, the rigidity, the thickness, and the like.

Further, a printing layer may be provided between the plastic sheet and the photocurable resin layer. The printing method is not particularly limited, and printing can be performed by a conventionally known method such as offset printing, gravure printing, flexographic printing, and screen printing.

In the present invention, the photocurable resin layer provided on the plastic sheet is preferably composed of a solvent-free photocurable composition.
As described above, when the printing layer is provided in advance on the plastic sheet, for example, when a multicolor printing machine is used, the photocurable resin layer may be continuously provided on the printing layer after the printing layer is provided. It will be possible. By using the solvent-free photocurable composition, it is not necessary to process the print layer itself to give solvent resistance, and once the print sheet is wound, the photocurable resin layer is provided again. Since the labor can be saved, the productivity of the hard coat sheet can be improved. Further, the printing layer may be provided on the opposite surface of the sheet surface provided with the photocurable resin layer.

The hard coat sheet of the present invention is suitable for case assembly because it has high transparency and is excellent in slipperiness, scratch resistance and bendability.
For example, the hard coat sheet of the present invention can be punched into a predetermined shape and bent along a polygonal line formed on the surface of the hard coat sheet to be assembled.

<Packaging case>
The packaging case of the present invention is made by using the hard coat sheet of the present invention.
Examples of the packaging case include a plastic sheet packaging case suitable for storing cosmetics, daily necessities, and other items for sale, exhibition, and the like.
A packaging case can be obtained by bending the hard coat sheet of the present invention along a polygonal line formed on the surface of the packaging case, assembling the sheet, or attaching the sheet to the surface of the case.
Since a part or all of the surface of the packaging case is covered with the hard coat sheet of the present invention, even if the packaging cases rub against each other during transportation of the packaging case, the surface is slippery and the surface is scratch resistant. Since it is excellent, the surface of the packaging case is not easily scratched and the transparency is not impaired, so that the contents are excellent in visibility.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. The evaluation method and sample processing method in Examples and Comparative Examples are as follows. Further, "parts" in Examples and Comparative Examples indicates "parts by mass".

<Manufacturing of polyester A>
100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, and 0.07 part of calcium acetate monohydrate were taken in a reactor, heated and heated, and methanol was distilled off to carry out a transesterification reaction. It took about four and a half hours after the reaction started. Then, the temperature was raised to 230 ° C., and the transesterification reaction was substantially completed. Next, 0.04 part of phosphoric acid and 0.035 part of antimony trioxide were added, and the mixture was polymerized according to a conventional method. That is, the reaction temperature was gradually increased to 280 ° C., while the pressure was gradually reduced to 0.05 mmHg. After 4 hours, the reaction was terminated and chips were obtained according to a conventional method to obtain polyester A. The intrinsic viscosity of the obtained polyester A was 0.75 (d / l).

<Manufacturing of polyester B>
In the above method for producing polyester A, silica particles having an average particle size of 4.5 μm were produced in the same manner as polyester A except that 0.15 parts by mass were added to obtain polyester B. The intrinsic viscosity of the obtained polyester B was 0.75 (d / l).

<Manufacturing of polyester C>
In the above method for producing polyester B, polyester C was produced by the same method as polyester B except that ethylene glycol was 67 mol% and 1,4-cyclohexanedimethanol was 33 mol% as diol components. The intrinsic viscosity of the obtained polyester C was 0.68 (d / l).

<Manufacturing of unstretched polyester sheet 1>
The polyester C is used as a raw material for the surface layer (B), and the polyester A is used as a raw material for the base layer (A). An amorphous sheet (250 μm) in which two types and three layers were laminated on the surface layer (back surface) was obtained. The thickness structure of each layer is 25 μm / 200 μm / 25 μm.

<Manufacturing of unstretched polyester sheet 2>
The polyester B is used as a raw material for the surface layer (B), and the polyester A is used as a raw material for the base layer (A). An amorphous sheet (250 μm) in which two types and three layers were laminated on the surface layer (back surface) was obtained. The thickness structure of each layer is 25 μm / 200 μm / 25 μm.
Hereinafter, the unstretched polyester sheet 1 and the unstretched polyester sheet 2 may be referred to as an unstretched PET sheet.

<Preparation of photocurable composition>
The following components were used to prepare the photocurable composition.
Each component was mixed according to the component compositions shown in Tables 1 and 2, and photocurable compositions of Examples and Comparative Examples were prepared.

[Polyfunctional (meth) acrylate and urethane (meth) acrylate]
(A1)
A mixture of pentaerythritol triacrylate: pentaerythritol tetraacrylate: urethane acrylate (isophorone skeleton) = 52.6: 44.6: 2.8 (mass%) was used. Here, the urethane acrylate is a reaction product of isophorone diisocyanate and pentaerythritol tri (meth) acrylate.

(A2)
A mixture having a mixing ratio (mass basis) of pentaerythritol triacrylate: pentaerythritol tetraacrylate: urethane acrylate: inorganic oxide particles = 50.1: 42.0: 2.8: 5.1 (mass%) was used.
As the inorganic oxide particles, silica particles (average particle size: 50 nm) were used.
(A3)
Dipentaerythritol hexaacrylate 100% by mass

[Photopolymerization initiator]
(B1)
BASF's "Irgacure 184"[1-hydroxy-cyclohexyl-phenyl-ketone; compound (2)]
(B2)
BASF's "Irgacure 907" [2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one; compound (1)]
(B3)
BASF's "Irgacure 127" [2-hydroxy1-{4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one; compound (3) ]

[Fluorine compounds]
(C1)
"RS76-NS" (leveling agent) manufactured by DIC Corporation
[Silicone compounds]
(D1)
"KP-341" (leveling agent) manufactured by Shin-Etsu Chemical Co., Ltd.

<Manufacturing of hard coat sheet>
[Examples 1 and 2, and Comparative Examples 1 and 2]
An unstretched polyester sheet 1 was used as the plastic sheet.
The photocurable composition having the composition shown in Table 1 or 2 is applied to the surface of the unstretched PET sheet, and the coating thickness (after drying) is the layer thickness shown in Table 1 or Table 2 (for example, 0.4 μm in Example 1). It was applied so as to become. The obtained photocurable composition film was irradiated with ultraviolet rays using a UV irradiation device (model: UVC-05016S1AGF) (irradiation conditions: 11.2 W / cm), and a hard having a photocurable resin layer was provided. I got a coat sheet.

[Example 3]
A hard coat sheet was obtained in the same manner as in Example 1 except that the type of the plastic sheet was changed to a polypropylene sheet (PP sheet) (thickness: 250 μm).

[Example 4]
In Example 2, a hard coat sheet was obtained in the same manner as in Example 2 except that the type of plastic sheet was changed to unstretched polyester sheet 2 (thickness 250 μm).

[Example 5]
In Example 1, a hard coat sheet was obtained in the same manner as in Example 1 except that the photocurable composition: toluene solvent = 1: 1 (mass basis) was diluted and applied to the sheet surface.

[Comparative Example 3]
A hard coat sheet was obtained by producing in the same manner as in Example 2 except that the photocurable composition having the composition shown in Table 1 was changed to A3.

[Comparative Example 4]
The photocurable composition was not applied to the unstretched polyester sheet 1, and the unstretched polyester sheet 1 was used as it was.

[Comparative Example 5]
The photocurable composition having the composition shown in Table 2 was produced in the same manner as in Example 2 except that the thickness of the hard coat layer was changed to 1 μm to obtain a hard coat sheet.

<Measurement of physical properties of polyesters A, B, C>
(1) Method for measuring the intrinsic viscosity (d / l) of polyesters A, B and C The intrinsic viscosity of polyesters A, B and C is 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed. Weighed, 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) was added and dissolved, and the measurement was carried out at 30 ° C.

(2) Average particle size of particles in polyesters A, B, and C The average particle size of particles in polyesters A, B, and C is the centrifugal sedimentation type particle size distribution measuring device SA-CP3 manufactured by Shimadzu Corporation. Was measured by the sedimentation method based on the resistance value of the stock.

<Evaluation of hard coat sheet and sheet of Comparative Example 4>
1. 1. Photocurable Resin Layer Thickness For each of the hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and 5, a contact type surface roughness meter (SurF Coder ET4000A, manufactured by Kosaka Research Institute Co., Ltd.) was used. , The layer thickness of the photocurable resin layer was measured. The measurement results are shown in Tables 1 and 2.

2. Curability of Photocurable Composition Each of the hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was measured with a spectrophotometer (UV-2450, manufactured by Shimadzu Corporation). The absorbance at the wavelength was measured to evaluate the curability of the photocurable composition. The larger this value is, the better the curability is. The evaluation results are shown in Tables 1 and 2.

3. 3. Optical Properties 3-1) Transparency The transparency of the hard coat sheet and the sheet of Comparative Example 4 was evaluated from the viewpoint of light transmittance and haze.
Specifically, the hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and the sheets of Comparative Example 4 were used with a haze meter (NDH5000 manufactured by Nippon Denshoku Kogyo Co., Ltd.). The light transmittance and the haze value were measured. The evaluation results are shown in Tables 1 and 2.

3-2) Glossiness Glossiness was also evaluated as an optical characteristic of the hard coat sheet.
The hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and the sheets of Comparative Example 4 were subjected to a glossiness using a multi-angle gloss meter (GS-4K, manufactured by Suga Test Instruments Co., Ltd.). Was measured. The evaluation results are shown in Tables 1 and 2.

4. Scratch resistance The scratch resistance of the hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and the sheet of Comparative Example 4 is compared with the presence or absence of scratches and light generated when the sheets are rubbed against each other. It was evaluated from the viewpoint of the surface hardness of the curable resin layer. The evaluation results are shown in Tables 1 and 2.
4-1) Rubbing of Sheets With respect to the hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and the sheets of Comparative Example 4, the surfaces of the photocurable resin layers are aligned with each other. After rubbing the hard coat sheets or the sheets of Comparative Example 4 against each other, the presence or absence of scratches was visually confirmed.
(Evaluation criteria)
⊚: No scratches are confirmed ○: Scratches are very slightly confirmed.
Δ: Scratches are partially confirmed.
X: Scratches are clearly confirmed on the entire surface.

4-2) Surface hardness For each of the hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and 5 and the sheet of Comparative Example 4, an ultrafine hardness tester (manufactured by Shimadzu Corporation, DUH-). In W201), the surface hardness of the photocurable resin layer was measured. The measurement results are shown in Tables 1 and 2.

5. Slipperiness Regarding the slipperiness of the photocurable resin layer of each of the hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and the sheet of Comparative Example 4, the coefficient of static friction was determined according to JIS K 7125. It was measured. The measurement results are shown in Tables 1 and 2.

6. Processability 6-1) Continuous processability Regarding the continuous processability of each hard coat sheet obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and 5, after providing a print layer on the surface of the plastic sheet, the print layer was formed. A hard coat layer was continuously provided on the opposite surface of the provided sheet surface. Then, the state of the print layer was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 and 2.

(How to apply the print layer)
A printing layer composition (manufactured by Toyo Ink Co., Ltd .: Flash Dry FD S New R1 Indigo) was applied to the surface of the plastic sheet so that the coating thickness (after drying) was 1 μm. The obtained print layer composition film was irradiated with ultraviolet rays using a UV irradiation device (model: UVC-05016S1AGF) (irradiation conditions: 11.2 W / cm) to provide a print layer.
(Evaluation criteria)
◯: The print layer does not come off even if the print layer is rubbed with a fingertip.
Δ: When the print layer is rubbed with a fingertip, the print layer may be easily peeled off.
(During hard coat lamination, the print layer is likely to be partially peeled off due to the influence of the volatile solvent generated during the drying process.)

6-2) Bending property The foldability of each of the hard coat sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 3 and the sheet of Comparative Example 4 is evaluated from the viewpoint of the presence or absence of cracks in the photocurable resin layer. Evaluated from.
After each hard coat sheet and the sheet of Comparative Example 4 were folded in half, the creases were observed with an optical microscope to confirm the presence or absence of cracks in the photocurable resin layer. The evaluation results are shown in Tables 1 and 2.
(Evaluation criteria)
◯: No crack.
×: There is a crack.

In Tables 1 and 2, the amount (% ^* ) of "urethane (meth) acrylate" indicates the amount of urethane (meth) acrylate in (A1) to (A3).
As can be seen from Tables 1 and 2, at least one selected from the group consisting of polyfunctional (meth) acrylate, urethane (meth) acrylate, photopolymerization initiator, and fluorine compound and silicone compound on at least one side of the plastic sheet. A hard coat sheet on which a photocurable resin layer having a thickness of 0.1 to 0.8 μm obtained by curing a photocurable composition containing a compound is laminated has excellent curability of the photocurable composition. It can be seen that even if the photocurable resin layer is a thin film, it is excellent in scratch resistance and bending property, excellent in slipperiness, and high in transparency.

The hard coat sheets of Examples 1 and 2 using the unstretched PET sheet as the plastic sheet were more transparent than the hard coat sheet of Example 3 using the polypropylene sheet.
Further, as the plastic sheet, the hard coat sheets of Examples 1 and 2 using the unstretched polyester sheet 1 containing polyester C having a diol component having a structure derived from ethylene glycol and a structure derived from 1,4-cyclohexanedimethanol were used. Adhesion between the sheet and the hard coat layer when stored for a long period of time in the state of the hard coat sheet as compared with the hard coat sheet of Example 4 using the unstretched polyester sheet 2 containing the polyester B containing no diol component. Was hard to decrease over time.

Further, since the hard coat sheets of Examples 1 and 2 form a photocurable resin layer without diluting the photocurable composition with an organic solvent, printing is performed even if the printing layer is present on the plastic sheet. Since it is not necessary to consider the deterioration of the layer and the drying step of the organic solvent is not required, the hard coat sheet is produced as compared with the hard coat sheet of Example 5 formed by diluting the photocurable composition with the organic solvent. Excellent in sex.

The hard coat sheets of Examples 1 and 2 in which the photocurable resin layer was formed using the photocurable composition containing urethane (meth) acrylate were photocurable without using urethane (meth) acrylate. Compared with the hard coat sheet of Comparative Example 3 having a resin layer, it was excellent in bendability.

The sheet of Comparative Example 4 having no photocurable resin layer was excellent in optical properties and bendability, but was not excellent in scratch resistance and slipperiness. Further, the hard coat sheet of Comparative Example 5 in which the layer thickness of the photocurable resin layer exceeded 0.8 μm was not excellent in bendability.

Since the hard coat sheet of the present invention is excellent in transparency, slipperiness, scratch resistance and bendability, it is particularly suitable as a packaging case made of a plastic sheet and a case assembling sheet for assembling the packaging case. For example, cosmetics, daily necessities, and other items can be stored and sold or exhibited, and their industrial value is high.

Claims (9)

A photocurable composition containing at least one selected from the group consisting of a polyfunctional (meth) acrylate, a urethane (meth) acrylate, a photopolymerization initiator, and a fluorine compound and a silicone compound on at least one side of a plastic sheet. A photocurable resin layer having a cured thickness of 0.1 to 0.8 μm is laminated, and the cured resin layer is laminated.
The plastic sheet is an unstretched polyester sheet, the unstretched polyester sheet is at least two copolymerized polyester layers, and the polyester layer on the photocurable resin layer side is derived from terephthalic acid as a dicarboxylic acid component. A hard coat sheet for assembling a case, which comprises a polyester having a structure derived from the above and a structure derived from ethylene glycol and a structure derived from 1,4-cyclohexanedimethanol as a diol component. The hard coat sheet for assembling a case according to claim 1, wherein the compounding ratio of the polyfunctional (meth) acrylate and the urethane (meth) acrylate is 80/20 to 97.2 / 2.8. The hard coat sheet for assembling a case according to claim 1 or 2, wherein the urethane (meth) acrylate contains isophorone diisocyanate as a constituent unit. A photocurable composition containing at least one selected from the group consisting of a polyfunctional (meth) acrylate, a urethane (meth) acrylate, a photopolymerization initiator, and a fluorine compound and a silicone compound on at least one side of a plastic sheet. A photocurable resin layer having a cured thickness of 0.1 to 0.8 μm is laminated, and the cured resin layer is laminated.
The polyfunctional (meth) mixing ratio of the acrylate and the urethane (meth) acrylate, a 80/20 to 97.2 / 2.8, to case assembly for a hard coat sheet. The hard coat sheet for assembling a case according to claim 4, wherein the urethane (meth) acrylate contains isophorone diisocyanate as a constituent unit. A photocurable composition containing at least one selected from the group consisting of a polyfunctional (meth) acrylate, a urethane (meth) acrylate, a photopolymerization initiator, and a fluorine compound and a silicone compound on at least one side of a plastic sheet. A photocurable resin layer having a cured thickness of 0.1 to 0.8 μm is laminated, and the cured resin layer is laminated.
The urethane (meth) acrylate, including isophorone diisocyanate as a constituent unit, to case assembly for a hard coat sheet. The hard coat sheet for assembling a case according to any one of claims 4 to 6, wherein the plastic sheet is an unstretched polyester sheet or a polypropylene sheet. The hard coat sheet for case assembly according to any one of claims 1 to 7, wherein the polyfunctional (meth) acrylate contains at least one selected from pentaerythritol triacrylate and pentaerythritol tetraacrylate. A packaging case using the hard coat sheet for assembling the case according to any one of claims 1 to 8.