Varnish composition, laminate, laminate with printed layer, PTP lid material and PTP

Abstract

Provided is a varnish composition capable of forming a protective receiving layer for PTP that has excellent receptivity to ultraviolet-curable inkjet ink, adhesion to metal foil, and heat resistance. [Solution] A varnish composition for forming a protective receiving layer for PTP, comprising a binder resin (A), a melamine resin (B), and an organic solvent (C), wherein the binder resin (A) comprises a (meth)acrylic resin (A1) having a hydroxyl group and an ultraviolet-curable functional group, the hydroxyl value of the (meth)acrylic resin (A1) being 2.0 mgKOH / g or more, and the content of the (meth)acrylic resin (A1) in terms of solid content being 60 to 100 mass% relative to the total mass of the solid content of the binder resin (A).

Description

[Technical Field]

[0001] The present invention relates to a varnish composition, a laminate, a laminate with a printed layer, a lid material for PTP, and a PTP. [Background technology]

[0002] Press-through packs (PTPs) are commonly used when individually packaging medications such as tablets and capsules. PTPs are typically manufactured by bonding a blister container with a pocket for storing medications to a metal foil lid via a heat-seal layer. Blister containers are typically manufactured by molding plastic sheets such as polypropylene (PP), polyvinyl chloride (PVC), and amorphous polyethylene terephthalate (A-PET).

[0003] In PTP applications, metal foil is typically printed by gravure printing or the like with information, such as the product name of the drug or other product to be contained, as well as a design, on the side where a heat-seal layer for bonding to a blister container is laminated and on the opposite side. In addition, to protect the printed layer formed by gravure printing or the like from high external heat (for example, heat during heat-sealing processing) and friction, an overprint varnish (hereinafter also referred to as OP varnish) may be laminated on the surface of the printed layer. Patent Document 1 discloses a packaging sheet for PTP lid materials, which has a coating layer containing titanium oxide on the front side of an aluminum foil, and an overcoat layer on the surface of the coating layer, the overcoat layer containing at least one of an epoxy resin, a nitrocellulose resin, and an acrylic resin as a main component, and which has a heat seal layer on the back side of the aluminum foil.

[0004] Recently, there has been a widespread demand for variable information such as manufacturing dates and lot numbers for pharmaceuticals to be printed on PTPs. Therefore, inkjet printing using UV-curable inkjet inks has been attempted. This makes it possible to print a wide variety of information in small lots. However, it is very difficult to directly laminate a UV-curable inkjet ink onto a metal foil from the viewpoint of adhesion to the metal foil. Therefore, a layer that acts as an adhesion promoter is required between the metal foil and the UV-curable inkjet ink. This layer is required to have excellent receptivity to the UV-curable inkjet ink, excellent adhesion to the metal foil, and heat resistance that can withstand the high heat applied during the subsequent lamination. Patent Document 2 discloses a metal foil coated with a coating layer formed from a PTP coating composition containing a cellulose resin, an epoxy resin, a melamine resin, and an acrylic resin, and having an inkjet ink laminated on the coating layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-040072 [Patent Document 2] Japanese Patent Publication No. 2023-060716 Summary of the Invention [Problem to be solved by the invention]

[0006] The overcoat layer described in Patent Document 1 is not intended for printing with ultraviolet-curable inkjet ink, and does not have the receptivity for ultraviolet-curable inkjet ink. Although the coating layer described in Patent Document 2 is said to have receptivity to ultraviolet-curable inkjet ink, the effect is not necessarily sufficient, and further improvement is required. In addition, there is still room for improvement in the adhesion to metal foil and heat resistance required for OP varnish applications.

[0007] The present invention has been made in consideration of the above circumstances, and its object is to provide a varnish composition capable of forming a protective receiving layer for PTPs that has excellent receptivity to ultraviolet-curable inkjet inks, adhesion to metal foils, and heat resistance, as well as a laminate, a laminate with a printed layer, a PTP lid material, and a PTP that use the same. [Means for solving the problem]

[0008] The present invention has the following aspects. [1] A varnish composition for forming a protective receiving layer for a PTP, Contains a binder resin (A), a melamine resin (B), and an organic solvent (C), the binder resin (A) contains a (meth)acrylic resin (A1) having a hydroxyl group and an ultraviolet-curable functional group, the (meth)acrylic resin (A1) has a hydroxyl value of 2.0 mgKOH / g or more, A varnish composition, wherein the content of the (meth)acrylic resin (A1) in terms of solid content is 60 to 100 mass % relative to the total mass of the solid content of the binder resin (A). [2] The varnish composition according to [1], wherein the total content of the binder resin (A) and the melamine resin (B) in terms of solid content is 90 to 99 mass % relative to the total mass of the solid content of the varnish composition. [3] The varnish composition according to [1] or [2], wherein the mass ratio of the melamine resin (B) to the binder resin (A) is 0.03 to 0.8 in terms of solid content. [4] The varnish composition according to any one of [1] to [3], wherein the ultraviolet-curable (meth)acrylic resin (A1) has a weight-average molecular weight of 5,000 to 50,000. [5] The varnish composition according to any one of [1] to [4], further comprising an acid catalyst (D). [6] The varnish composition according to any one of [1] to [5], further comprising a hydrocarbon wax (E). [7] The varnish composition according to any one of [1] to [6], further comprising silica (F). [8] The varnish composition according to any one of [1] to [7], which is for gravure printing. [9] A metal foil and a protective receiving layer for PTP formed on one side of the metal foil, The protective receiving layer for PTP is a layer formed using the varnish composition according to any one of [1] to [8], and contains a reaction product of the (meth)acrylic resin (A1) and the melamine resin (B), and the reaction product has the ultraviolet-curable functional group.

[10] The laminate according to [9], further comprising a pattern layer between the metal foil and the protective receiving layer for PTP.

[11] The laminate according to [9] or

[10] , further comprising a heat seal layer on the other surface of the metal foil.

[12] The laminate according to

[11] , further comprising a design layer between the metal foil and the heat seal layer.

[13] A laminate with a printed layer, comprising a printed layer formed using an ultraviolet-curable inkjet ink on the surface of the PTP protection receiving layer of the laminate described in [9].

[14] A lid material for PTP, comprising the laminate according to any one of [9] to

[12] .

[15] A PTP lid material comprising the laminate with a printed layer according to

[13] .

[16] A PTP comprising a plastic sheet having a pocket for accommodating an item to be packaged and the PTP lid material described in

[14] .

[17] A PTP comprising a plastic sheet having a pocket for accommodating an item to be packaged and the PTP lid material described in

[15] . [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a varnish composition capable of forming a protective receiving layer for PTPs that has excellent receptivity to ultraviolet-curable inkjet inks, adhesion to metal foils, and heat resistance, as well as a laminate, a laminate with a printed layer, a PTP lid material, and a PTP that use the same. [Brief explanation of the drawings]

[0010] [Figure 1]1 is a schematic cross-sectional view showing an example of a laminate with a printed layer of the present embodiment. [Figure 2] 1 is a schematic cross-sectional view showing an example of a PTP according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below by showing embodiments. The following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from the spirit of the present invention. In the present invention, the "protective receiving layer for PTP" refers to a protective layer (OP varnish) that covers the design layer in a PTP, particularly in the cover material of the PTP, and protects the design layer from external heat and friction, and / or a layer that functions as a receiving layer for the ultraviolet-curable inkjet ink printed on its surface. In this specification, the contents of the binder resin (A), melamine resin (B), acid catalyst (D), hydrocarbon wax (E), silica (F), and other optional components are all calculated as solid contents. "Solid content" refers to the components contained in the varnish composition excluding volatile media such as organic solvents, and is the component that will ultimately form the coating film (printed layer). Specifically, it is measured in accordance with JIS K 5601-1-2:2008. The term "(meth)acryloyl group" refers to an acryloyl group or a methacryloyl group. The same applies to "(meth)acrylate" and "(meth)acrylic acid". The symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. For the sake of convenience, the scale of each part in the drawings may differ from the actual scale. In the following, "ultraviolet rays" will also be abbreviated as "UV."

[0012] [Varnish composition] The varnish composition of this embodiment is a varnish composition for forming a protective receiving layer for PTP (hereinafter also simply referred to as "protective receiving layer"). The varnish composition of this embodiment is typically printed on the metal foil that constitutes the lid material for PTP. PTPs will be described in detail later.

[0013] The varnish composition of this embodiment contains the following binder resin (A), melamine resin (B), and organic solvent (C). The varnish composition of this embodiment may, if necessary, further contain at least one component selected from the group consisting of an acid catalyst (D), a hydrocarbon wax (E), silica (F), and other components (hereinafter also referred to as "other optional components"), as long as the effects of the present invention are not impaired.

[0014] <Binder resin (A)> The binder resin (A) contains a (meth)acrylic resin (A1) having a hydroxyl group and a UV-curable functional group. The binder resin (A) may further contain a binder resin other than the (meth)acrylic resin (A1) within the range that does not impair the effects of the present invention.

[0015] "(Meth)acrylic resin (A1)" The (meth)acrylic resin (A1) is a resin whose main chain is made of (meth)acrylic monomer units and which has hydroxyl groups and UV-curable functional groups on its side chains and / or at the ends of the main chain. The (meth)acrylic resin (A1) may have a hydroxyl group on a side chain, at a terminal of the main chain, or on both sides. The (meth)acrylic resin (A1) may have a UV-curable functional group on a side chain, at the end of the main chain, or on both sides.

[0016] The UV-curable functional group is typically a functional group containing a polymerizable unsaturated bond. The UV-curable functional group is not particularly limited, but a representative example is a (meth)acryloyl group. When the varnish composition contains the (meth)acrylic resin (A1), the protective receptor layer has excellent receptivity to UV-curable inkjet ink. Since the varnish composition contains the (meth)acrylic resin (A1), UV-curable functional groups are present on the surface of the protective receptor layer. The UV-curable inkjet ink also contains a component with a UV-curable functional group. When the UV-curable inkjet ink is applied to the surface of the protective receptor layer and cured by UV irradiation, a crosslinking reaction occurs between the UV-curable functional groups of the protective receptor layer and the UV-curable functional groups of the UV-curable inkjet ink, which is thought to result in excellent receptivity for the UV-curable inkjet ink. After the UV-curable inkjet ink is cured, the protective receptor layer may or may not contain a UV-curable functional group.

[0017] The (meth)acrylic resin (A1) is not particularly limited as long as it has a hydroxyl group and a UV-curable functional group, and examples thereof include a reaction product obtained by reacting (addition reaction) a polymer having units based on an epoxy group-containing (meth)acrylate with (meth)acrylic acid, and a reaction product obtained by reacting (addition reaction) a polymer having units based on (meth)acrylic acid with a (meth)acrylate having an epoxy group. The polymer having units based on an epoxy group-containing (meth)acrylate and the polymer having units based on (meth)acrylic acid may each further have units based on a polymerizable monomer other than the epoxy group-containing (meth)acrylate and (meth)acrylic acid.

[0018] Examples of the (meth)acrylate having an epoxy group include (meth)acrylates having a glycidyl group such as glycidyl (meth)acrylate and β-methylglycidyl (meth)acrylate, and (3,4-epoxycyclohexyl)methyl (meth)acrylate. The (meth)acrylate having an epoxy group may be used alone or in combination of two or more kinds.

[0019] Examples of other polymerizable monomers include (meth)acrylic acid esters and styrene-based monomers. Examples of (meth)acrylic acid esters include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate; (meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (meth)acrylic acid aryl esters such as phenyl (meth)acrylate and naphthyl (meth)acrylate; and (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. Examples of the styrene-based monomer include styrene, α-methylstyrene, vinyltoluene, and derivatives thereof. The other polymerizable monomers may be used alone or in combination of two or more.

[0020] The hydroxyl value (hereinafter also referred to as OH value) of the (meth)acrylic resin (A1) is 2.0 mgKOH / g or more, preferably 2.0 to 300 mgKOH / g, more preferably 2.0 to 200 mgKOH / g, and particularly preferably 2.0 to 150 mgKOH / g. If the OH value of the (meth)acrylic resin (A1) is less than the above-mentioned lower limit, the network-forming crosslinking reaction between the (meth)acrylic resin (A1) and the melamine resin (B) does not proceed sufficiently, resulting in reduced heat resistance and abrasion resistance of the protective receiving layer. If the OH value of the (meth)acrylic resin (A1) is more than the above-mentioned upper limit, the blocking resistance of the protective receiving layer is slightly reduced. The OH value is a value measured in accordance with JIS K 1557-1.

[0021] The number of UV-curable functional groups that the (meth)acrylic resin (A1) has in one molecule is not particularly limited, but may be 1 to 20, further 1 to 15, or even 1 to 10.

[0022] The weight average molecular weight (hereinafter also referred to as Mw) of the (meth)acrylic resin (A1) is preferably 5,000 to 50,000, more preferably 8,000 to 48,000, and particularly preferably 10,000 to 45,000. If the Mw of the (meth)acrylic resin (A1) is less than the above lower limit, the heat resistance, abrasion resistance, and blocking resistance of the protective receptor layer will be slightly reduced. If the Mw of the (meth)acrylic resin (A1) is more than the above upper limit, the receptivity of the protective receptor layer to UV-curable inkjet ink and adhesion to metal foil will be slightly reduced. Mw is a value calculated in terms of standard polystyrene determined by gel permeation chromatography (GPC).

[0023] The glass transition temperature (hereinafter also referred to as Tg) of the (meth)acrylic resin (A1) is preferably 10 to 120°C, more preferably 20 to 100°C, and particularly preferably 30 to 90°C. If the Tg of the (meth)acrylic resin (A1) is less than the above lower limit, the heat resistance of the protective receiving layer will be slightly reduced. If the Tg of the (meth)acrylic resin (A1) is more than the above upper limit, the adhesion to the metal foil will be slightly reduced. Tg is determined in accordance with JIS K 7121 using a differential scanning calorimeter by heating 10 mg of a sample from -100°C to 160°C at a rate of 20°C / min, and is determined from the intersection of the baseline and the tangent to the endothermic curve in the DSC curve.

[0024] "Epoxy resin (A2)" The binder resin (A) may further contain an epoxy resin (A2) for the purpose of further improving heat resistance, within the range that does not impair the effects of the present invention. However, when the epoxy resin (A2) is contained, the content of the (meth)acrylic resin (A1) becomes relatively small, and therefore the acceptability for UV-curable inkjet inks decreases slightly.

[0025] Examples of the epoxy resin (A2) include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol E-type epoxy resins, bisphenol S-type epoxy resins, and bisphenol AD-type epoxy resins; novolac-type epoxy resins such as cresol novolac-type epoxy resins and phenol novolac-type epoxy resins; hydrogenated bisphenol-type epoxy resins such as hydrogenated bisphenol A-type epoxy resins, hydrogenated bisphenol F-type epoxy resins, hydrogenated bisphenol E-type epoxy resins, hydrogenated bisphenol S-type epoxy resins, and hydrogenated bisphenol AD-type epoxy resins; polyglycol-type epoxy resins obtained using polyether polyols such as polyethylene glycol and polypropylene glycol as raw materials; brominated epoxy resins, silicone-modified epoxy resins, urethane-modified epoxy resins, polyester-modified epoxy resins, polyamide-combined epoxy resins, amino resin-combined epoxy resins, and alkyd resin-combined epoxy resins. The epoxy resin (A2) may be used alone or in combination of two or more kinds.

[0026] "Cellulose-based resin (A3)" The binder resin (A) may further contain a cellulose-based resin (A3) for the purpose of further improving blocking resistance and from the standpoint of cost, within the range that does not impair the effects of the present invention. However, when the cellulose-based resin (A3) is contained, the content of the (meth)acrylic resin (A1) becomes relatively small, which slightly reduces the acceptability for UV-curable inkjet ink and also reduces the yellowing resistance due to heat during heat sealing. Therefore, in applications where design is required, it is preferable not to contain the cellulose-based resin (A3).

[0027] Examples of the cellulose-based resin (A3) include nitrocellulose; cellulose esters such as cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose acetate propionate, and cellulose acetate butyrate; and alkyl celluloses such as hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, and carboxypropyl cellulose. The cellulose-based resin (A3) may be used alone or in combination of two or more kinds.

[0028] <Melamine resin (B)> The melamine resin (B) is a thermosetting resin obtained by polycondensation of melamine and formaldehyde. The melamine resin (B) contains methylol groups obtained by polycondensation of melamine and formaldehyde. The number of methylol groups contained in the melamine resin (B) is not particularly limited and may be any number from 1 to 6. The methylol groups may be alkylated to form alkoxymethyl groups. By including the melamine resin (B) in the varnish composition, when the varnish composition is applied and then baked, a crosslinking reaction between the (meth)acrylic resin (A1) and the melamine resin (B) and a self-crosslinking reaction of the melamine resin (B) proceed in a mesh-like pattern, making it possible to form a protective receiving layer that has excellent heat resistance, adhesion to metal foil, abrasion resistance, and blocking resistance.

[0029] Examples of the melamine resin (B) include methylated melamine resin, ethylated melamine resin, propylated melamine resin, n-butylated melamine resin, i-butylated melamine resin, methylated ethylated melamine resin, methylated n-butylated melamine resin, and methylated i-butylated melamine resin. The melamine resin (B) may be used alone or in combination of two or more kinds.

[0030] <Organic solvent (C)> Examples of the organic solvent (C) include ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; monohydric alcohol-based organic solvents such as methanol, ethanol, n-propanol, i-propanol, and n-butanol; polyhydric alcohol-based organic solvents such as ethylene glycol, propylene glycol, and glycerin; ester-based organic solvents such as methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and i-butyl acetate; ether-based organic solvents such as tetrahydrofuran, dioxane, diethyl ether, and methyl ethyl ether; and n-hexane, n-heptane, and n-octane. aliphatic hydrocarbon organic solvents such as those mentioned above; glycol ester solvents such as propylene glycol monomethyl ether acetate; glycol ether solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and dipropylene glycol methyl ether; alicyclic hydrocarbon organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane; and aromatic hydrocarbon organic solvents such as toluene and xylene. The organic solvent (C) is preferably one that can dissolve the binder resin (A) and the melamine resin (B). The organic solvent (C) may be used alone or in combination of two or more kinds. The organic solvent (C) preferably contains a ketone organic solvent and an aromatic hydrocarbon organic solvent, since these solvents have excellent solubility in the binder resin (A) and the melamine resin (B) and excellent printability.

[0031] <Acid catalyst (D)> The varnish composition may contain an acid catalyst (D) for the purpose of further improving heat resistance, adhesion to metal foil, abrasion resistance, and blocking resistance. This effect is thought to be due to the acid catalyst (D) accelerating the crosslinking reaction of the melamine resin (B) during baking. Examples of the acid catalyst (D) include dodecylbenzenesulfonic acid, p-toluenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, alkylphosphoric acid, and phenylphosphoric acid. Among these, dodecylbenzenesulfonic acid and p-toluenesulfonic acid are particularly preferred. The acid catalyst (D) may be either a blocked acid catalyst or an unblocked acid catalyst. The acid catalyst (D) may be used alone or in combination of two or more kinds.

[0032] <Hydrocarbon Wax (E)> The varnish composition may contain a hydrocarbon wax (E) for the purpose of further improving rub resistance and blocking resistance. Examples of hydrocarbon waxes (E) include polyethylene wax, Fischer-Tropsch wax, paraffin wax, microcrystalline wax, and polypropylene wax. Among these, polyethylene wax and Fischer-Tropsch wax are preferred. Examples of polyethylene wax include high-density polymerized polyethylene, low-density polymerized polyethylene, oxidized polyethylene, acid-modified polyethylene, and special monomer-modified polyethylene. Fischer-Tropsch wax is a wax produced by the Fischer-Tropsch process using carbon monoxide and hydrogen as raw materials, and has a nearly saturated, unbranched, linear molecular structure. The hydrocarbon wax (E) may be used alone or in combination of two or more kinds.

[0033] The penetration (hardness) of the hydrocarbon wax (E) at 25°C as defined in JIS K 2207 is preferably not more than 30, more preferably not more than 20, and particularly preferably not more than 15. If the penetration of the hydrocarbon wax (E) exceeds the upper limit, the abrasion resistance and printability will be slightly reduced.

[0034] <Silica (F)> The varnish composition may contain silica (F) for the purpose of further improving the abrasion resistance and blocking resistance. Silica (F) may be either natural or synthetic. The synthesis method may be either a dry method or a wet method. Known dry methods include the combustion method and the arc method. Known wet methods include the precipitation method and the gel method. Silica (F) may be either crystalline or amorphous, and may be either hydrophobic or hydrophilic. The silica (F) may be used alone or in combination of two or more kinds.

[0035] The average particle size of silica (F) is preferably 0.1 to 10 μm, more preferably 1 to 8 μm, and particularly preferably 2 to 6 μm. If the average particle size of silica (F) is less than the above lower limit, the effects of improving abrasion resistance and blocking resistance may not be fully achieved. If the average particle size of silica (F) is more than the above upper limit, the storage stability and printability of the varnish composition may be slightly reduced. The average particle size of silica (F) means the particle size at 50% cumulative value (D50) in the volume-based particle size distribution, and can be determined by a laser diffraction / scattering method.

[0036] <Other optional ingredients> Examples of other optional components include extender pigments, rosin derivatives, chelating agents, lubricants, anti-settling agents, UV absorbers, antioxidants, antistatic agents, leveling agents, thickeners, surfactants, antifoaming agents, plasticizers, dispersants, stabilizers, etc. One type of other optional component may be used alone, or two or more types may be used in combination. Note that UV-curable ink compositions, including UV-curable inkjet inks, typically contain a photopolymerization initiator in addition to a component having a UV-curable functional group in order to UV-cure the coating film. However, the varnish composition of the present embodiment does not typically contain a photopolymerization initiator because it does not UV-cure the coating film.

[0037] <Content of each ingredient> The content of the (meth)acrylic resin (A1) in terms of solid content is 60 to 100 mass %, preferably 65 to 100 mass %, and more preferably 70 to 100 mass %, based on the total mass of the solid content of the binder resin (A). If the content of the (meth)acrylic resin (A1) is less than the above lower limit, the binder resin (A) will not contain enough hydroxyl groups and UV-curable functional groups derived from the (meth)acrylic resin (A1), resulting in reduced acceptability for UV-curable inkjet inks and reduced adhesion to metal foils.

[0038] The total content of the binder resin (A) and the melamine resin (B) in the varnish composition, calculated as solid content, is preferably 90 to 99 mass%, more preferably 92 to 98.5 mass%, and particularly preferably 94 to 98 mass%, based on the total mass of the solid content of the varnish composition. If the total content of the binder resin (A) and the melamine resin (B) is less than the above lower limit, the acceptability for UV-curable inkjet ink and heat resistance will be slightly reduced. If the total content of the binder resin (A) and the melamine resin (B) is more than the above upper limit, the adhesion to metal foil will be slightly reduced.

[0039] The mass ratio of melamine resin (B) to binder resin (A) in terms of solid content is preferably 0.03 to 0.8, more preferably 0.05 to 0.6, and particularly preferably 0.08 to 0.5. If the mass ratio of melamine resin (B) to binder resin (A) in terms of solid content is less than the above lower limit, the heat resistance, abrasion resistance, and blocking resistance will be slightly reduced. If the mass ratio of melamine resin (B) to binder resin (A) in terms of solid content is more than the above upper limit, the heat resistance, adhesion to metal foil, abrasion resistance, and blocking resistance will be slightly reduced.

[0040] The content of the organic solvent (C) is preferably 20 to 90% by mass relative to the total mass of the varnish composition.

[0041] When the organic solvent (C) contains a ketone organic solvent and an aromatic hydrocarbon organic solvent, the content of the ketone organic solvent in the organic solvent (C) is preferably 20 to 80 mass% relative to the total mass of the organic solvent (C).The content of the aromatic hydrocarbon organic solvent in the organic solvent (C) is preferably 20 to 80 mass% relative to the total mass of the organic solvent (C).

[0042] When the varnish composition contains an acid catalyst (D), the content of the acid catalyst is preferably 0.3 to 7 mass%, more preferably 0.5 to 5 mass%, and particularly preferably 1 to 3 mass%, based on the total mass of the solids of the varnish composition. If the content of the acid catalyst (D) is less than the above lower limit, the effects of improving heat resistance, adhesion to metal foil, abrasion resistance, and blocking resistance may not be fully achieved. If the content of the acid catalyst (D) is more than the above upper limit, blocking resistance will be slightly reduced.

[0043] When the varnish composition contains a hydrocarbon wax (E), the content of the hydrocarbon wax (E) is preferably 0.1 to 3 mass%, more preferably 0.3 to 2 mass%, and particularly preferably 0.5 to 1 mass%, based on the total mass of the solids of the varnish composition. If the content of the hydrocarbon wax (E) is less than the above lower limit, the effects of improving abrasion resistance and blocking resistance may not be fully achieved. If the content of the hydrocarbon wax (E) is more than the above upper limit, printability and heat resistance may be slightly reduced.

[0044] When the varnish composition contains silica (F), the content of silica (F) is preferably 0.05 to 2 mass%, more preferably 0.08 to 1 mass%, and particularly preferably 0.1 to 0.5 mass%, relative to the total mass of the solids in the varnish composition. If the content of silica (F) is less than the above lower limit, the effects of improving abrasion resistance and blocking resistance may not be fully achieved. If the content of silica (F) exceeds the above upper limit, the storage stability, fluidity, and printability of the varnish composition may be slightly reduced.

[0045] <Method of manufacturing varnish composition> The varnish composition of this embodiment can be obtained, for example, by dissolving or dispersing the (meth)acrylic resin (A1), the melamine resin (B), and, if necessary, optional components in the organic solvent (C). The method for dissolving or dispersing each component in the organic solvent (C) is not particularly limited and can be performed by a known method. Examples include a dissolver, paint shaker, ball mill, attritor, sand mill, bead mill, dyno mill, roll mill, ultrasonic mill, high-pressure collision disperser, etc. In this case, one method may be used once or multiple times, or two or more methods may be used in combination multiple times.

[0046] <Action and effect> The varnish composition of the present embodiment described above contains a binder resin (A), a melamine resin (B), and an organic solvent (C), wherein the binder resin (A) contains a (meth)acrylic resin (A1) having a hydroxyl group and a UV-curable functional group, the (meth)acrylic resin (A1) having an OH value of 2.0 mgKOH / g or more, and the content of the (meth)acrylic resin (A1) converted into solid content is 60 to 100 mass% relative to the total mass of the solid content of the binder resin (A), and therefore a protective receiving layer can be formed that has excellent receptivity to UV-curable inkjet ink, adhesion to metal foil, and heat resistance.

[0047] [Laminate] The laminate of this embodiment includes a metal foil and a protective receiving layer formed on one surface of the metal foil. The laminate may further comprise a heat seal layer on the other side of the metal foil. The laminate may further comprise a design layer between the metal foil and the protective receiving layer and / or between the metal foil and the heat seal layer. In the laminate of this embodiment, the protective receiving layer is located as the outermost layer on one side of the metal foil, and no other layers (for example, a printed layer formed using a UV-curable inkjet ink) are formed on top of it.

[0048] <Metal foil> As the metal foil, aluminum foil is preferred from the viewpoints of availability and cost, and hard aluminum foil is preferred because the lid material is less likely to stretch and tear when the non-packaged item is pushed out of the pocket portion of the PTP. The thickness of the metal foil is, for example, 15 to 30 μm.

[0049] <Protective Receptive Layer> The protective receptor layer is a layer formed using the varnish composition of this embodiment and contains a reaction product of a (meth)acrylic resin (A1) and a melamine resin (B). This reaction product has a UV-curable functional group derived from the (meth)acrylic resin (A1). This reaction product is produced by a crosslinking reaction between the (meth)acrylic resin (A1) and the melamine resin (B) and a self-crosslinking reaction of the melamine resin (B). The protective receptor layer can be formed by applying the varnish composition of this embodiment to one side of a metal foil and baking it. If necessary, drying may be performed before baking. UV irradiation is not performed when forming the protective receptor layer, so that the UV-curable functional groups of the (meth)acrylic resin (A1) remain. The method for applying the varnish composition is not particularly limited, and known application methods such as gravure printing, flexographic printing, brush coating, gravure coater method, die coater method, bar coater method, spray coating method, flow coating method, dip coating method, spin coating method, and curtain coating method can be used. Among these, gravure printing and flexographic printing are preferred because they have excellent drying properties and are suitable for high-speed printing, and gravure printing is particularly preferred because it can ensure an appropriate application amount required to achieve various required physical properties. Therefore, it is particularly preferred that the varnish composition of this embodiment is for gravure printing. The baking method is not particularly limited, and examples include heating in an oven set at about 200°C for about 10 seconds, or blowing hot air at about 260°C. The thickness of the protective receiving layer is, for example, 0.5 to 5 μm.

[0050] <Picture layer> The pattern layer (the first pattern layer, the second pattern layer) is optionally provided to display invariant information such as the product name and pattern of the packaged item to be packaged in PTP, etc. The pattern layer can be formed by applying ink onto at least one surface of the metal foil and drying it. Known inks can be used. The method of applying the ink can be a known method according to the ink. For example, a method similar to the method of applying a varnish composition can be mentioned. The thickness of the pattern layer is, for example, 0.5 to 5 μm.

[0051] <Heat seal layer> The heat seal layer is used to bond the metal foil (the pattern layer may be formed thereon) and the plastic sheet (blister container) of PTP. The heat seal layer typically contains a heat-sealable resin. Examples of the heat-sealable resin include polyester, modified polyester, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polypropylene (PP), etc. The heat seal layer can be formed by a known method. The thickness of the heat seal layer is, for example, 1 to 20 μm.

[0052] 〔Laminated body with printing layer〕 The laminated body with a printing layer of the present embodiment includes a printing layer (hereinafter also referred to as a "UV-IJ ink layer") formed using UV-curable inkjet ink (hereinafter also referred to as "UV-IJ ink") on the surface of the protective receiving layer of the laminated body of the present embodiment.

[0053] <UV-IJ ink layer> The UV-IJ ink layer is provided, for example, to display variable information such as the manufacturing date and lot number of the packaged item to be packaged in PTP. The UV-IJ ink layer can be formed by applying UV-IJ ink onto the protective receiving layer using an inkjet printer and irradiating it with UV. Known UV-IJ inks and inkjet printers can be used. UV-IJ inks typically contain a component containing a UV-curable functional group, a photopolymerization initiator, a pigment, a dispersant, and a sensitizer. Examples of the component containing a UV-curable functional group include monofunctional monomers, monofunctional oligomers, multifunctional monomers, and multifunctional oligomers. The thickness of the UV-IJ ink layer is, for example, 1 to 10 μm.

[0054] FIG. 1 is a schematic cross-sectional view showing an example of a laminate with a printed layer of the present embodiment. In this example, the laminate 10 with a printed layer comprises a metal foil 11, a first pattern layer 12 formed on one side of the metal foil 11, a protective receiving layer 13 formed on the first pattern layer 12, a UV-IJ ink layer 14 formed on the protective receiving layer 13, a second pattern layer 15 formed on the other side of the metal foil 11, and a heat seal layer 16 formed on the second pattern layer 15. A laminate 10 with a printed layer may be obtained by forming a UV-IJ ink layer 14 on the surface of the protective receiving layer 13 of a laminate in which a first pattern layer 12 and a protective receiving layer 13 are formed on one side of the metal foil 11 and a second pattern layer 15 and a heat seal layer 16 are formed on the other side of the metal foil 11, or by forming a UV-IJ ink layer 14 on the surface of the protective receiving layer 13 of a laminate in which a first pattern layer 12 and a protective receiving layer 13 are formed on one side of the metal foil 11 and a second pattern layer 15 and a heat seal layer 16 are not formed on the other side of the metal foil 11, and then forming a second pattern layer 15 and a heat seal layer 16 on the other side of the metal foil 11 to obtain a laminate 10 with a printed layer.

[0055] [PTP] The PTP of this embodiment includes a plastic sheet and a PTP lid material. The plastic sheet is a so-called blister container having a pocket portion for accommodating a packaged item. The PTP lid material includes the laminate of this embodiment or the laminate with a printed layer of this embodiment.

[0056] FIG. 2 is a schematic cross-sectional view showing an example of the PTP of this embodiment. The PTP 1 in this example has a plastic sheet 3 and a PTP lid material 5 . The plastic sheet 3 has a pocket portion 3a for accommodating the packaged item X. The PTP lid material 5 is attached to one surface (the upper surface in the drawing) of the plastic sheet 3 to seal the opening of the pocket portion 3a.

[0057] The plastic constituting the plastic sheet may be a known plastic, such as polypropylene (PP), polyvinyl chloride (PVC), or amorphous polyethylene terephthalate (A-PET). The thickness of the plastic sheet is, for example, 50 to 500 μm. The plastic sheet can be produced by molding a pocket into a flat plastic sheet. The pocket can be formed by a known method, such as a heat press method. The depth and shape of the pocket can be appropriately set depending on the packaged item to be contained.

[0058] After the packaged item is placed in the pocket of the plastic sheet, the plastic sheet and the PTP lid material are bonded together by the heat seal layer of the PTP lid material and one side of the plastic sheet, thereby obtaining a package in which the packaged item is packaged in the PTP. The packaged items are not particularly limited, and examples thereof include medicines such as tablets and capsules, and foods. The plastic sheet and the PTP lid material can be bonded together by a known method. A PTP lid material having a UV-IJ ink layer formed thereon (a laminate with a printed layer of this embodiment) may be bonded to a plastic sheet, or a PTP lid material having no UV-IJ ink layer formed thereon (a laminate of this embodiment) may be bonded to a plastic sheet, and then a UV-IJ ink layer may be formed on the protective receiving layer. [Example]

[0059] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0060] (Raw materials used) The following compounds were used:

[0061] <(Meth)acrylic resin (A1), comparison product> A1-1: UV-curable (meth)acrylic resin, OH value: 4.4 mg KOH / g, Mw: 20,000, Tg: 77°C A1-2: UV-curable (meth)acrylic resin, OH value: 77 mg KOH / g, Mw: 40,000, Tg: 53°C A1-3: UV-curable (meth)acrylic resin, OH value: 115 mg KOH / g, Mw: 65,000, Tg: 107°C A1-4: (Meth)acrylic resin, OH value: 21 mg KOH / g, Mw: 20,000, Tg: 41°C It should be noted that A1-4 does not fall under the category of the (meth)acrylic resin (A1) in that it does not have a UV-curable functional group. A1-5: UV-curable (meth)acrylic resin, OH value: 235 mg KOH / g, Mw: 40,000, Tg: 53°C A1-6: UV-curable (meth)acrylic resin, OH value: 1.2 mg KOH / g, Mw: 20,000, Tg: 64°C

[0062] <Epoxy resin (A2)> A2-1: Manufactured by Sankyo Kasei Co., Ltd., product name "Epototo YD-011" <Cellulose-based resin (A3)> A3-1: Cellulose acetate butyrate, product name "CAB-551-0.01", manufactured by Eastman Chemical Company

[0063] <Melamine resin (B)> B-1: Cymel 303LF, manufactured by Allnex Japan B-2: Made of Changchun artificial resin, product name "Sumimar M-40ST"

[0064] <Organic solvent (C)> ·MEK / Tol: Methyl ethyl ketone / toluene = 1 / 1 (mass ratio)

[0065] <Acid catalyst (D)> ·D-1: Dodecylbenzenesulfonic acid ·D-2: p-Toluenesulfonic acid

[0066] <Hydrocarbon wax (E)> ·E-1: Manufactured by Mitsui Chemicals, Inc., trade name "Hiwax 220P", melting point 110 °C, penetration 13 <Silica (F)> ·F-1: Manufactured by Fuji Silysia Chemical Ltd., trade name "Silohobic 200", hydrophobic silica, average particle size 3.9 μm <Other optional components> ·Anti-settling agent: Manufactured by Enomoto Kasei Co., Ltd., trade name "Disparon PFA-131"

[0067] <UV curable inkjet ink (UV-IJ ink)> The following two types of UV-IJ inks were prepared. AL1: Manufactured by Dainichi Seiko Kogyo Co., Ltd., trade name "UV-IJ AL-ink 1" AL2: Manufactured by Dainichi Seiko Kogyo Co., Ltd., trade name "UV-IJ AL-ink 2" The composition of each UV-IJ ink is shown in Table 1. In Table 1, "NV." indicates the solid content. "%" indicates mass %. [[ID=—]]

[0068] [[ID=—]] [[ID=—]]

Table 1

[0069] [[ID=—]] (Examples 1 to 18, Comparative Examples 1 to 7)[[ID=—]] <Preparation of varnish composition>[[ID=—]] According to the compositions shown in Tables 2 to 3, the binder resin (A), melamine resin (B), organic solvent (C), and other components were mixed, and the resulting mixture was stirred with a dissolver to obtain a varnish composition.[[ID=—]] [[ID=—]]

[0070] [[ID=—]] <Production of printed matter> The prepared varnish composition was diluted with a mixed solvent of methyl ethyl ketone:toluene = 1:1 (mass ratio) so that the viscosity at 20 °C measured using a Zahn cup #3 was 18 seconds, and a printing varnish was prepared. Using a gravure printing machine equipped with a heliogravure 175 lines / inch engraving plate (manufactured by Matsuo Sangyo Co., Ltd., trade name "K Printing Proof"), the prepared printing varnish was applied to the matte surface of a hard aluminum foil (thickness: 20 μm). Then, by baking at 200 °C for 10 seconds, a protective receiving layer was formed to obtain a printed matter.

[0071] The following evaluations were performed on the obtained printed matter. The results are shown in Tables 2 to 3.

[0072] <Evaluation of UV-IJ ink receptivity> The UV-IJ inks shown in Tables 2 to 3 were applied to the surface of the protective receiving layer of the printed matter using a bar coater #3, and a UV-IJ ink layer was formed by irradiating with UV twice under the conditions of 1 metal halide lamp 120 W / cm and 50 m / min. After sticking cellophane tape (manufactured by Nichiban Co., Ltd.) on the surface of the obtained UV-IJ ink layer, this cellophane tape was quickly peeled off. This operation was performed 3 times at the same location, and then the state of the UV-IJ ink layer was visually confirmed, and the UV-IJ ink receptivity was evaluated according to the following evaluation criteria. 5: The ratio of the peeled area to the total area of the UV-IJ ink layer is 0%. 4: The ratio of the peeled area to the total area of the UV-IJ ink layer is more than 0% and less than 5%. 3: The ratio of the peeled area to the total area of the UV-IJ ink layer is more than 5% and less than 20%. 2: The ratio of the peeled area to the total area of the UV-IJ ink layer is more than 20% and less than 50%. 1: The ratio of the peeled area to the total area of the UV-IJ ink layer is more than 50%.

[0073] <Evaluation of heat resistance> The printed surfaces (protective receiving layer side) of two identical printed materials were placed together, and one of the printed materials was subjected to heat seal testing at 220-260°C (in 20°C increments) and 2 kg / cm using a heat seal tester (manufactured by Tester Sangyo Co., Ltd., product name "TP-701-C Heat Seal Tester"). 2 After that, the two printed materials were peeled off, and the state of the printed surface of each printed material was visually inspected, and the heat resistance was evaluated according to the evaluation criteria shown below. 5: When heated at 260°C, neither sticking of the printed surfaces nor defects in the appearance of the printed surfaces were observed. 4: When heated at 260°C, only slight sticking between printed surfaces was observed. 3: When heated at 240°C, only slight sticking between printed surfaces was observed. When heated at 260°C, both sticking between printed surfaces and poor appearance of the printed surfaces were observed. 2: When heated at 220°C, only slight sticking between printed surfaces was observed. When heated at 240°C, both sticking between printed surfaces and poor appearance of the printed surfaces were observed. 1: When heated at 220°C, both the printed surfaces stuck together and the appearance of the printed surfaces became poor.

[0074] <Evaluation of adhesion to metal foil> Cellophane tape (manufactured by Nichiban Co., Ltd.) was applied to the surface of the protective receptor layer of the printed matter, and then the cellophane tape was quickly peeled off. This operation was repeated three times at the same location, and then the condition of the protective receptor layer was visually inspected and the adhesion to the metal foil was evaluated according to the following evaluation criteria. 5: The ratio of the peeled area to the total area of ​​the protective receiving layer is 0%. 4: The ratio of the peeled area to the total area of ​​the protective receiving layer is more than 0% and less than 5%. 3: The ratio of the peeled area to the total area of ​​the protective receiving layer is more than 5% and less than 20%. 2: The ratio of the peeled area to the total area of ​​the protective receiving layer is more than 20% and less than 50%. 1: The ratio of the peeled area to the total area of ​​the protective receiving layer is more than 50%.

[0075] <Evaluation of heat yellowing resistance> Two identical printed materials were placed one on top of the other, and a heat seal tester (manufactured by Tester Sangyo Co., Ltd., product name "TP-701-C Heat Seal Tester") was used to test one of the printed materials at 260°C and 2 kg / cm 2 After that, the two printed materials were peeled off, and the state of the protective receptor layer of each printed material was visually inspected, and the heat yellowing resistance was evaluated according to the following evaluation criteria. 5: No yellowing was observed in the protective receptor layer. 4: Slight yellowing was observed in the protective receptor layer. 3: Slight yellowing was observed in the protective receptor layer. 2: Yellowing was observed in the protective receptor layer. 1: Severe yellowing was observed in the protective receptor layer.

[0076] <Abrasion resistance> A rubbing test was conducted on the printed surface of the printed matter by rubbing it back and forth 100 times with a black cloth (gold cloth No. 3) under a load of 200 gf using a Gakushin-type rubbing fastness tester (manufactured by Tester Sangyo Co., Ltd., product name "AB-301"). After that, the appearance of the protective-receptive layer was visually confirmed, and the rubbing resistance was evaluated according to the evaluation criteria shown below. 5: The ratio of the area that has migrated to the black cloth (gold cloth No. 3) side to the total area of ​​the protective receiving layer is 0%. 4: The ratio of the area that has migrated to the black cloth (gold cloth No. 3) side to the total area of ​​the protective receiving layer is more than 0% and less than 10%. 3: The ratio of the area that has migrated to the black cloth (gold cloth No. 3) side to the total area of ​​the protective receiving layer is 10% or more but less than 30%. 2: The ratio of the area that has migrated to the black cloth (gold cloth No. 3) side to the total area of ​​the protective receiving layer is 30% or more but less than 50%. 1: The ratio of the area that has migrated to the black cloth (gold cloth No. 3) side to the total area of ​​the protective receiving layer is 50% or more and 100% or less.

[0077] <Evaluation of blocking resistance> The printed surface of the printed material is placed on hard aluminum foil, and the pressure is 4 kg / cm 2A load of 1000 kJ / cm was applied to the printed material, and the printed material was stored for 24 hours in a thermostatic chamber at 40° C. Thereafter, the printed material was peeled off from the hard aluminum foil, and the blocking resistance was evaluated according to the following evaluation criteria. 5: No peel resistance. 4: Slight sticking was observed. 3: Sticking was confirmed. 2: Peelable, but hard aluminum foil deforms. 1: Difficult to peel off.

[0078] [Table 2]

[0079] [Table 3]

[0080] In Tables 2 and 3, "NV." indicates solid content. "%" indicates mass %. "Total," "Total solid content," "Proportion of (A) + (B) in solid content," "(A1) / (A) × 100," and "(B) / (A)" are values ​​for the varnish composition. [Industrial Applicability]

[0081] The varnish composition of the present invention can form a protective receiving layer for PTP that is excellent in various physical properties such as receptivity to UV-curable inkjet ink, adhesion to metal foil, and heat resistance. [Explanation of symbols]

[0082] 1 PTP 3 plastic sheets 3a Pocket 5 Lid material for PTP 10 Laminate with printed layer 11 Metal foil 12 First pattern layer 13 Protective Receptor Layer 14 UV-IJ ink layer (printed layer formed using UV-curable inkjet ink) 15 Second pattern layer 16 Heat seal layer

Claims

1. A varnish composition for forming a protective receiving layer for a PTP, comprising: Contains a binder resin (A), a melamine resin (B), and an organic solvent (C), the binder resin (A) contains a (meth)acrylic resin (A1) having a hydroxyl group and an ultraviolet-curable functional group, the (meth)acrylic resin (A1) has a hydroxyl value of 2.0 mgKOH / g or more, A varnish composition in which the content of the (meth)acrylic resin (A1) in terms of solid content is 60 to 100 mass % based on the total mass of the solid content of the binder resin (A).

2. 2. The varnish composition according to claim 1, wherein the total content of the binder resin (A) and the melamine resin (B) in terms of solid content is 90 to 99 mass % relative to the total mass of the solid content of the varnish composition.

3. 2. The varnish composition according to claim 1, wherein the mass ratio of the melamine resin (B) to the binder resin (A) is 0.03 to 0.8 in terms of solid content.

4. 2. The varnish composition according to claim 1, wherein the (meth)acrylic resin (A1) has a weight average molecular weight of 5,000 to 50,000.

5. 2. The varnish composition according to claim 1, further comprising an acid catalyst (D).

6. 2. The varnish composition according to claim 1, further comprising a hydrocarbon wax (E).

7. 2. The varnish composition according to claim 1, further comprising silica (F).

8. The varnish composition according to any one of claims 1 to 7, which is for gravure printing.

9. A metal foil and a protective receiving layer for a PTP formed on one side of the metal foil, The protective receiving layer for the PTP is a layer formed using the varnish composition described in any one of claims 1 to 7, and includes a reaction product of the (meth)acrylic resin (A1) and the melamine resin (B), and the reaction product has the ultraviolet-curable functional group.

10. The laminate according to claim 9, further comprising a design layer between the metal foil and the protective receiving layer for the PTP.

11. The laminate according to claim 9, further comprising a heat seal layer on the other side of the metal foil.

12. The laminate according to claim 11, further comprising a design layer between the metal foil and the heat seal layer.

13. A laminate with a printed layer, comprising a printed layer formed using an ultraviolet-curable inkjet ink on the surface of the protective receiving layer for PTP of the laminate according to claim 9.

14. A lid material for PTP, comprising the laminate according to claim 9.

15. A PTP lid material comprising the printed layer-attached laminate according to claim 13.

16. A PTP comprising a plastic sheet having a pocket for accommodating an item to be packaged, and the PTP lid material according to claim 14.

17. A PTP comprising: a plastic sheet having a pocket portion for accommodating an item to be packaged; and the PTP lid material according to claim 15.

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