JP7199635B2 - Packaging material having glitter printed layer, and method for producing the same - Google Patents

Description

The present invention relates to packaging materials. In particular, it relates to a packaging material having a bright printed layer containing a bright pigment that can be used in microwave ovens and retort pouches.

Packaging materials are sometimes decorated with metallic decorations from the viewpoint of producing a sense of luxury and luxury of the packaged objects and creating a beautiful appearance. Conventionally, as such a means of decoration, a base material on which a metal such as aluminum is vapor-deposited has been used in some cases, but in recent years, the number of cases in which decoration is performed using a printed layer using aluminum paste or other bright pigments has increased. rice field.

Moreover, in recent years, packaging materials have become highly functional, and include those having retort resistance and those having resistance to microwave ovens. However, even in the case of a laminated packaging material having a printed layer using the bright pigment between substrates, delamination (floating) in boiling or retorting, sparks when microwaved, etc. was pointed out to be happening. Particularly in terms of resistance to microwave ovens, it is difficult to use luster pigments made from metals in printed layers of packaging materials, and such usage patterns have generally been avoided.

Therefore, various efforts have been made to avoid the above problems. For example, Patent Document 1 discloses a packaging material including a printed layer made of an ink for a bright printed layer that uses aluminum paste as a bright pigment and uses a urethane resin as a binder resin. It is said that there is no Further, for example, Patent Document 2 describes an invention in which a resin-coated aluminum paste is used to improve retort resistance and laminate strength.

However, when microwave oven or retort heating is performed, there are many cases where problems such as difficulty in tearing when opening the packaging material occur. It is thought that this is due to the deterioration of the bright printed layer, etc. On the other hand, it is thought that the ease of opening can be improved by reducing the content of the bright pigment in the printed layer. It is difficult to satisfy sexuality.

Japanese Patent Application Laid-Open No. 2020-33109 JP 2010-053193 A

It is an object of the present invention to provide a packaging material which has designability, resistance to microwave ovens and boiling/retorting, and which can be easily opened by tearing even after heating.

As a result of diligent studies, the inventors have found that the above problems can be solved by using the packaging material of the present invention, and have completed the present invention.

That is, the present invention is a packaging material having at least a substrate, a glitter print layer, an adhesive layer and a sealant in this order,
The glitter print layer contains a glitter pigment and a urethane resin and is crosslinked with an isocyanate curing agent, and the isocyanate curing agent has a weight average molecular weight of 800 to 8000 ,
The luster pigment includes a pearl pigment, and the pearl pigment has an average particle size of 2 to 200 μm .

The present invention also relates to the packaging material, wherein the mass ratio of the urethane resin and the isocyanate curing agent is 99:1 to 60:40.

The present invention also relates to the packaging material, wherein the isocyanate-based curing agent has a molecular weight distribution (Mw/Mn) of 1.5 to 5.

The present invention also relates to the packaging material, wherein the urethane resin contains polyester-derived structural units.

The present invention also relates to the packaging material, wherein the urethane resin has a molecular weight distribution (Mw/Mn) of 1.5 to 5.

The present invention also relates to the above packaging material, wherein the base material is a polyester base material or a polyamide base material.

The present invention also relates to the above packaging material, wherein the luster pigment further contains scale aluminum.

The present invention also relates to the packaging material for microwave ovens or boiling retort pouches.

The present invention also provides a method for producing a packaging material having at least a base material, a glitter print layer, an adhesive layer and a sealant in this order,
The glitter printing layer comprises a glitter ink containing a glitter pigment containing a pearl pigment having an average particle diameter of 2 to 200 μm , a urethane resin, and an isocyanate curing agent having a weight average molecular weight of 800 to 8000. The present invention relates to a method of manufacturing packaging, including the process of being formed by printing or flexographic printing.

According to the present invention, it is possible to provide a packaging material that has good design and resistance to microwave ovens and boiling/retorting, and that can be easily opened by tearing even after heating.

Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of embodiments of the present invention, and the present invention does not exceed the gist thereof. Content is not limited.

The packaging material of the present invention will be described in detail below.
The present invention relates to a packaging material having at least a base material, a glitter printed layer, an adhesive layer and a sealant in this order, wherein the printed layer contains a glitter pigment and a urethane resin and is crosslinked with an isocyanate curing agent. and the isocyanate-based curing agent has a weight average molecular weight of 800 to 8,000.
The glitter printed layer only needs to have a decorative appearance, and by using a glitter pigment and urethane resin, the adhesion to the substrate etc. is improved, and the weight average molecular weight of the isocyanate type is 800 to 8000. Cross-linking with a curing agent makes the entire packaging material durable and easily tearable even after heating in a microwave oven or boiling/retorting.

In this specification, a printed layer that does not contain a glitter pigment is called an "ink layer", in contrast to a "glitter printed layer". The glittering print layer is sometimes referred to as a "glitter printing layer" and a "glitter layer", but they have the same meaning.

<Packaging material>
The packaging material of the present invention is a packaging material having a configuration in which at least a base material, a glittering print layer, an adhesive layer and a sealant are laminated in this order from the outer layer side. Specifically, the lamination structure can be exemplified by the following lamination structure in order from the outer layer side (left side). In addition, in the structural representations (1) to (4) below, "/" means the boundary of each layer.
(1) Base material/Glitter print layer/Adhesive layer/Sealant (2) Base material/Glitter print layer/Adhesive layer/Intermediate base material layer/Adhesive layer/Sealant (3) Base material/Glitter print Layer/Ink layer/Adhesive layer/Sealant (4) Substrate/Glitter printed layer/Ink layer/Adhesive layer/Intermediate substrate layer/Adhesive layer/Sealant ) can be arbitrarily selected.

<Glitter printing layer>
The packaging material of the present invention has a glitter printed layer between the substrate and the sealant. The glitter print layer may be provided on the entire surface of the base material, or may be provided on a part of the area of the base material. Moreover, you may have an ink layer further. The glitter printed layer of the packaging material of the present invention contains a urethane resin and a glitter pigment and is crosslinked with an isocyanate curing agent having a weight average molecular weight of 800 to 8,000.
The thickness of the glitter printed layer is preferably 0.5 to 10 μm, more preferably 0.8 to 7 μm, still more preferably 1.0 μm, from the viewpoint of giving a sufficient impression of metallic luster. 0 to 5 μm.

(Glitter ink)
The glitter printed layer can be formed by printing and applying a glitter ink. The glitter ink contains a urethane resin as a binder resin and an isocyanate curing agent in addition to the glitter pigment described above.

(Luminous pigment)
The luster pigment preferably contains at least one selected from pearl pigments and metal flakes.

(pearl pigment)
As pearl pigments, for example, white pearl pigments, interference pearl pigments, colored pearl pigments, and the like are preferably exemplified. Pearl pigments are suitable because they tend to improve the microwave resistance of packaging materials. Generally, the coloring effect of pigments is based on the phenomenon of light absorption and scattering by pigment particles. Pearl pigments, on the other hand, have special optical properties such as natural pearl-like deep luster, iris colors, or metallic effects that are obtained by utilizing the multi-reflection and interference phenomena of light in the thin film on the surface of the pigment. pigment.

The white pearl pigment is obtained by covering a scaly matrix of mica, aluminum, glass or the like with a coating layer made of a colorless material with a high refractive index such as titanium dioxide. They are relatively small, on the order of 15 μm, and reflect almost all wavelengths of light, giving them a white, silvery or iridescent appearance. The interference pearl pigment has a coating layer made of a colorless high refractive index material such as titanium dioxide, and the thickness of the coating layer is greater than that of the white pearl pigment, exceeding 0.15 μm. This thickness changes the reflected and transmitted light, resulting in different interference colors. It is sometimes called an iris colored pearl.
The colored pearl pigment is a chromatic color, and the coating layer is made of a colored high refractive index material such as ferric oxide, and the white pearl pigment is surrounded by a colored high refractive index material such as ferric oxide or other colored There are those that are coated with pigments, and those that have pigments or other coloring agents added to the coating layer.

The average particle size of the pearl pigment is preferably 2 to 200 μm, more preferably 3 to 100 μm, further preferably 5 to 70 μm. This is because the gloss is good while having microwave resistance and retort resistance. In addition, the said average particle diameter says the measured value by a laser-light-scattering method, and is a value of D50 (cumulative mass 50% particle diameter).

The content of the pearl pigment in the glitter print layer (that is, the content of the pearl pigment in the total glitter ink solid content) is 15 to 55 in the total mass of the glitter print layer (out of the total glitter ink solid content). % by mass, more preferably 20 to 50% by mass, still more preferably 25 to 45% by mass.

(metal scale)
Metals and alloys such as aluminum, gold, silver, brass, titanium, chromium, nickel, nickel-chromium, and stainless steel are suitably used as materials for the metal scales. Among them, aluminum flakes are preferred.

Metal scales are preferably non-leafing type metal scales. The non-leafing type metal flakes are uniformly dispersed in the process of forming the glitter printed layer, so that they have good design and excellent lamination strength as a packaging material. Therefore, even when heated in a microwave oven or boil/retort, the durability is improved. Non-leafing type metal flakes are preferably those in which oleic acid, linoleic acid, linolenic acid and other unsaturated fatty acids are adsorbed on the surface of the metal.

It is also preferable that the metal scales are coated with an acrylic resin on the surface of the metal scales. The resin-coated metal flakes have excellent lamination strength as a packaging material, and thus have good durability even when heated in a microwave oven, boil/retort. Resin-coated metal flakes can be produced, for example, by the methods described in JP-A-2010-053193 and JP-A-2012-241039.

The average particle size of the metal scales is preferably 3 to 30 μm, more preferably 4 to 25 μm, still more preferably 5 to 20 μm, particularly preferably 8 to 15 μm. . If the particle size is 3 μm or more, the appearance quality of printed matter is improved. If the thickness is 80 μm or less, the hiding power of the gravure ink coating film is improved, and the resistance to microwave ovens and retort resistance is also good. The average particle size of the metal particles is measured by a particle size distribution analyzer using light scattering. In the present invention, the particle size determined by the light scattering method was defined as the average particle size of the D50 value (50% cumulative mass particle size).

The content of metal flakes in the glitter print layer (that is, the content of metal flakes in the total glitter ink solid content) is 15 to 15 in the total mass of the glitter print layer (out of the total glitter ink solid content). It is preferably 55% by mass, more preferably 20 to 50% by mass, still more preferably 25 to 45% by mass.

The aspect ratio (average length/average thickness) of luster pigments such as pearl pigments and metal flakes is preferably 20 or more, more preferably 30 or more. Also, the aspect ratio of the bright pigment is preferably 400 or less, more preferably 200 or less, and even more preferably 100 or less. This is because the easy tearability after heating in a microwave oven and after retorting is improved.

(coloring agent)
The glitter print layer of the present invention may contain a coloring agent. Colorants include dyes, pigments and other colorants. Among them, it is preferable to contain a pigment, and the pigment can be either an organic pigment or an inorganic pigment. Examples of inorganic pigments include yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine blue, and cobalt blue. Examples of organic pigments include soluble azo-based, insoluble azo-based, azo-based, phthalocyanine-based, halogenated phthalocyanine-based, Anthraquinones, anthanthrones, dianthraquinonyls, anthrapyrimidines, perylenes, perinones, quinacridones, thioindigos, dioxazines, isoindolinones, quinophthalones, azomethinazos, flavanthrones, diketopyrrolo Pigments such as pyrrole-based, isoindoline-based, and indanthrone-based pigments can be used. Also, the C.I. I. Any pigment indicated by the pigment number can be used.

A yellow organic pigment is generally used at the same time in order to give the glitter printed layer a gold color. Examples of the yellow organic pigment include C.I. I. Pigment Yellow 1 to 219, yellow pigments that are organic compounds or organometallic complexes are preferred, for example, C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 3, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, Pigment Yellow 17, C.I. I. Pigment Yellow 24, C.I. I. Pigment Yellow 42, C.I. I. Pigment Yellow 55, C.I. I. Pigment Yellow 62, C.I. I. Pigment Yellow 65, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 83, C.I. I. Pigment Yellow 86, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 95, C.I. I. Pigment Yellow 109, C.I. I. Pigment Yellow 110, C.I. I. Pigment Yellow 117, C.I. I. Pigment Yellow 120, Pigment Yellow 125, C.I. I. Pigment Yellow 128, C.I. I. Pigment Yellow 129, C.I. I. Pigment Yellow 137, C.I. I. Pigment, Yellow 138, C.I. I. Pigment Yellow 139, C.I. I. Pigment Yellow 147, C.I. I. Pigment Yellow 148, C.I. I. Pigment Yellow 150, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 153, C.I. I. Pigment Yellow 154, C.I. I. Pigment Yellow 155, C.I. I. Pigment Yellow 166, C.I. I. Pigment Yellow 168, C.I. I. Pigment Yellow 174, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185 and C.I. I. Pigment Yellow 213 and the like are preferred. C. I. Pigment Yellow 83 and the like are preferably used.

The content of the colorant is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, and further preferably 30 to 50 parts by mass with respect to 100 parts by mass of the bright pigment. preferable.

(urethane resin)
The urethane resin used in the present invention is not limited to the following, but for example, a urethane prepolymer obtained by reacting a polyisocyanate and a polyol, and further a polyamine (chain extender) and, if necessary, a reaction terminator. A urethane resin obtained by a reaction may be mentioned. The urethane resin may be a resin having a urethane bond, and even if it has a urea bond or the like in addition to the urethane bond, it corresponds to the concept of the urethane resin. As the urethane resin, it is preferable to have a constitutional unit derived from polyester. In order to obtain a polyester-derived structural unit, for example, a polyester polyol is used as the polyol.

(polyisocyanate)
The polyisocyanate preferably contains a diisocyanate. Examples of the diisocyanate include aliphatic diisocyanates such as tetramethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate;
Cyclohexane-1,4-diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethyl Alicyclic diisocyanates such as xylylene diisocyanate and dimer diisocyanate obtained by converting the carboxyl group of dimer acid to an isocyanate group;
α,α,α',α'-tetramethylxylylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate , dimethyldiphenylmethane diisocyanate, tetramethyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, o-xylylene diisocyanate and 2,4-tolylene diisocyanate, aromatic diisocyanates such as 2,6-tolylene diisocyanate; Among these, alicyclic or araliphatic diisocyanates are preferred from the viewpoint of easy control of the reaction and good balance of performance of the resulting urethane resin, and in particular, isophorone diisocyanate, α, α, α', α '-Tetramethylxylylene diisocyanate is preferred. At least one type of diisocyanate may be used, and two or more types may be used in combination.

(polyol)
Polyols that can be used include polyester polyols, polyether polyols, polycarbonate polyols, and polyolefin polyols. The urethane resin preferably has structural units derived from polyester polyol. In this case, it is preferably 50% by mass or more (main component) in the total mass of the urethane resin.

The polyol used in the present invention preferably has a number average molecular weight of 500 to 10,000. Here, the number average molecular weight used in the polyol is calculated from the hydroxyl value. It is a value obtained by converting the amount of hydroxyl groups into the number of mg of potassium hydroxide, and is a value obtained according to JIS K0070. When the number average molecular weight of the polyol is 10,000 or less, the blocking resistance to plastic films is excellent. Further, when the number average molecular weight of the polyol is 500 or more, the flexibility of the urethane resin film is excellent and the adhesion to the plastic film is excellent. For the above reasons, the number average molecular weight is more preferably 1,000 to 5,000.

A diol is preferable as the polyol. In addition, a diol means a compound having two hydroxyl groups in one molecule. Examples of the diols include polyols such as polyester diols, polyether diols, polycarbonates and polybutadiene glycol. At least one type of diol may be used, and two or more types may be used in combination.

(polyester polyol)
The polyester polyol is preferably a polyester diol, and the polyester diol is preferably a polyester diol which is a condensate of a diol and a dicarboxylic acid.
Examples of the polyester diol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, and 1,8-octane. Diol, 1,9-nonanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 3,3,5-trimethylpentanediol, 2,4-diethyl -1,5-pentanediol, 1,12-octadecanediol, 1,2-alkanediol, 1,3-alkanediol, 1-monoglyceride, 2-monoglyceride, 1-monoglycerol ether, 2-monoglycerol ether, dimer Diols, hydrogenated dimer diols, and the like are preferred. A polyester polyol can be used individually or in mixture of 2 or more types. A polyester diol that is a condensate of a diol containing a branched diol and a dicarboxylic acid is preferred. Polyester diols obtained by ring-opening reaction of cyclic esters (such as lactones) may also be used.
Such dicarboxylic acids include adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, glutaric acid, 1 , 4-cyclohexyldicarboxylic acid, dimer acid, hydrogenated dimer acid, and the like, among which adipic acid, succinic acid, sebacic acid, and the like are preferable.
Furthermore, polyols having 3 or more hydroxyl groups and polyvalent carboxylic acids having 3 or more carboxyl groups can be used in combination as raw materials for polyester polyols.

Preferred specific examples of these include those containing a polyester-derived structural unit composed of a dibasic acid such as adipic acid, succinic acid, sebacic acid, and a diol having a branched structure. This is because the adhesiveness to the plastic substrate and the solubility of the ink composition can be improved. The diol having a branched structure is preferably a diol having a structure in which at least one hydrogen of alkylene glycol is substituted with an alkyl group. Examples of diols having a branched structure include 1,2-propanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyldiol, 1,4-pentanediol, 3-methyl-1,5-pentanediol, 2,5-hexanediol, 2-methyl -1,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,8-octanediol, 2,2 ,4-trimethyl-1,3-pentanediol and 2,2,4-trimethyl-1,6-hexanediol are preferred. Among them, at least one selected from 1,2-propanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, and 2-butyl-2-ethyl-1,3-propanediol is preferable. , 2-propanediol and/or 3-methyl-1,5-pentanediol are preferably used.

(polyether polyol)
Suitable polyether polyols include polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, and the like. These can be used alone or in combination of two or more. More specifically, it preferably contains polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol, and a copolymer composed of any of these, and may contain polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. It is more preferable.

(polyamine)
Preferably, the chain extender is a polyamine. Examples of the polyamine include, but are not limited to, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, and dimer diamine obtained by converting the carboxyl group of dimer acid into an amino group. Diamines are preferred. These can be used alone or in combination of two or more.
Amino acids can also be used for chain extension. Amino acid refers to a compound having both an amino group and an acidic functional group in one molecule, and preferably includes glutamine, asparagine, lysine, diaminopropionic acid, ornithine, diaminobenzoic acid, diaminobenzenesulfonic acid and the like. In the process of synthesizing the urethane resin, the acidic group is highly likely to remain unreacted with the isocyanate group, so that the acid value can be maintained in the urethane resin.

The reaction terminator is preferably a monoalcohol or monoamine in the case of a urethane resin that can be produced only in the urethanization step, and a monoamine in the case of a urethane resin that is produced by performing a urea reaction step in addition to the urethanization step. is preferred.
The monoalcohol is preferably a substituted or unsubstituted alcohol, such as methanol, ethanol, n-propanol, isopropyl alcohol, 1-butanol, and the like. The monoamine is preferably a substituted or unsubstituted monoamine, and preferred examples include n-butylamine, n-dibutylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, and dipropanolamine. Moreover, as the reaction terminator, the compounds exemplified as the chain elongation agent can also be used, and at least one of them may be used, and two or more of them can be used in combination.

In the production of a urethane prepolymer having terminal isocyanate groups obtained by reacting a polyisocyanate and a polyol, the molar equivalent ratio of the NCO of the polyisocyanate to the OH of the polyol (molar equivalent of the NCO of the polyisocyanate/mole of the OH of the polyol compound equivalent) is preferably 1.3 to 3, more preferably 1.5 to 2.

The urethane resin preferably has active hydrogen groups such as a hydroxyl value and/or an amine value. This is for obtaining a reaction site with a curing agent, which will be described later. The hydroxyl value is preferably 0.5 to 30 mgKOH/g, more preferably 1 to 20 mgKOH/g, even more preferably 2 to 15 mgKOH/g. When it has an amine value, it is preferably 0.1 to 15 mgKOH/g, more preferably 1 to 12 mgKOH/g. On the other hand, the acid value of the urethane resin is preferably 5 mgKOH/g or less, more preferably 3 mgKOH/g or less. This is because the acid value is difficult to react with the isocyanate-based curing agent described below.

The weight average molecular weight of the urethane resin is preferably from 5,000 to 100,000, more preferably from 5,000 to 80,000, and even more preferably from 10,000 to 60,000. This is because the bright print layer is formed into a strong film by cross-linking with a curing agent, which will be described later, and can withstand heating in a microwave oven and retort.
The weight average molecular weight of the present invention and the molecular weight distribution (Mw/Mn) described below can be measured by gel permeation chromatography (GPC). As an example, Water2690 (manufactured by Waters Co., Ltd.) and HLC-8220 (manufactured by Tosoh Corporation) are used as the GPC apparatus, PLgel, 5 μm, MIXED-D (manufactured by Polymer Laboratories), TSKgelSuperAW series (manufactured by Tosoh Corporation), etc. as the column. can be done. Tetrahydrofuran, 1,2,4-trichlorobenzene, N,N-dimethylformamide (0.01N-lithium bromide added) and the like can be used as a developing solvent at a flow rate of 0.5 to 1.5 ml/min. Preferably. An RI detector or the like can be used for detection, and measurement can be performed under conditions such as a sample injection concentration of 0.5 to 1.5 mg/ml and an injection amount of 0.1 to 1.0 microliter. A weight average molecular weight can be calculated|required as a polystyrene conversion value.

The molecular weight distribution (Mw/Mn) of the urethane resin is preferably from 1.5 to 5, and from 2 to
4 is more preferred, and 2.2 to 3.5 is even more preferred. Mw represents weight average molecular weight and Mn represents number average molecular weight. When Mw/Mn is within the above range, cross-linking with an isocyanate-based curing agent described below enhances cohesion and adhesion, exhibits sufficient resistance in microwave ovens, boiling, and retorting, and exhibits easy tearability. Then it is thought. Mw, Mn and Mw/Mn can be determined by gel permeation chromatography (GPC) as described above.

In order to make the molecular weight distribution (Mw/Mn) of the urethane resin within the above range, the selection of the urethane synthesis raw materials and the solid content mass ratio in the synthesis of the urethane resin, the dropping speed of the reactive raw material such as polyisocyanate in the synthesis reaction, and the stirring speed The molecular weight distribution (Mw/Mn) can be made within the range by appropriately setting the shape of the stirring blade and the reaction temperature. In the case of further chain extension reaction, it is effective to set the molecular weight distribution within a predetermined range by controlling the dropping rate and the temperature range in particular when the polyamine and the urethane prepolymer are reacted. It is important to control the reaction temperature. It is preferable to control the reaction temperature in the range of 50 to 130°C in the synthesis of the urethane prepolymer, and to control it in the range of 10 to 50°C in the reaction of the polyamine and the urethane prepolymer. preferable.
It is also effective to set the charging ratio of the reaction raw materials to an appropriate ratio to keep the molecular weight distribution within a predetermined range. The feed ratio includes, for example, the ratio of the hydroxyl groups of the polyol and the hydroxy acid, and the ratio of the isocyanate groups of the polyisocyanate, and the NCO/OH ratio, which is the ratio of the amino groups of the polyamine and the isocyanate groups of the urethane prepolymer. , amino group/NCO ratio, and the like. In order to control the molecular weight distribution, it is preferable to use a polymerization terminator (also referred to as a reaction terminator) for the purpose of preventing excessive polymerization reaction. Preferred examples of the polymerization terminator include monoalcohols and monoamines.

(Isocyanate curing agent)
In the packaging material of the present invention, an isocyanate-based curing agent is used in order to improve microwave oven resistance, retort resistance, and subsequent tearability. If the urethane resin has a hydroxyl group, amino group, or other active hydrogen group, it is crosslinked with the active hydrogen group. Laminate strength, easy tearability, etc. are improved. The urethane resin preferably has a hydroxyl group, an amino group, or other active hydrogen groups.

The weight-average molecular weight of the isocyanate-based curing agents conventionally used in packaging materials is as small as less than 600, and in most cases they are low-molecular-weight compounds. However, in this case, although there is no problem if it is simply used as a packaging material, when pearl pigments, metal flakes, etc. are included as pigment components, the cohesive force is insufficient and the properties are not satisfied. In addition, there is a concern that low-molecular-weight compounds may migrate to the substrate, ink layer, or adhesive layer.

Preferred embodiments of the isocyanate curing agent are shown below. The weight average molecular weight of the isocyanate-based curing agent is required to be 800 to 8,000, preferably 900 to 6,000, and more preferably 1,000 to 4,000. The molecular weight distribution (Mw/Mn) of the isocyanate-based curing agent is preferably 1.5-5, more preferably 2-5, and even more preferably 2-4. When the weight-average molecular weight and further Mw/Mn are within the above ranges, cohesion and adhesion are strengthened by the action of the urethane resin, exhibiting sufficient resistance in microwave ovens, boiling and retorting, and easy tearability. It is thought that it expresses

As the isocyanate-based curing agent, polyisocyanates including adduct-type polyisocyanate (adduct), biuret-type polyisocyanate (biuret), isocyanurate-type polyisocyanate (isocyanurate), etc. are suitable.
Biuret forms and isocyanurate forms are, for example, adduct forms obtained from the reaction of trimethylolpropane or other polyols with diisocyanates, biuret forms obtained by dimerizing diisocyanate and linked by biuret bonds, and obtained from cyclic trimerization reactions of diisocyanates. Examples include isocyanurate bodies and the like. As the diisocyanate, the diisocyanate described above may be arbitrarily selected and used, among which tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), and hexamethylene diisocyanate (HDI). , isophorone diisocyanate, xylylene diisocyanate (XDI), and hydrogenated xylylene diisocyanate (hydrogenated XDI). The adduct-type polyisocyanate, biuret-type polyisocyanate, and isocyanurate-type polyisocyanate may be used in combination, and may also be used in combination with other polyisocyanates.

In order to make the weight average molecular weight and molecular weight distribution (Mw/Mn) of the isocyanate curing agent within the above ranges, it is necessary to select diisocyanate, polyol, etc. in the synthesis of the isocyanate curing agent, the solid content mass ratio, and the polyisocyanate in the synthesis reaction. By appropriately setting the dropping speed of the reactive raw material, the stirring speed, the shape of the stirring blades, and the reaction temperature, it is possible to make it within the range. It is effective to set the molecular weight distribution within a predetermined range by controlling the dropping rate and the temperature range when reacting the polyamine and the polyisocyanate within a predetermined range.
Moreover, it is effective to set the molecular weight distribution within a predetermined range by setting the charging ratio of the reaction raw materials to an appropriate ratio. The feed ratio includes, for example, the NCO/OH ratio, which is the ratio of the isocyanate groups of the polyol and the polyisocyanate, and the amino group/NCO ratio, which is the ratio of the amino groups of the polyamine and the isocyanate groups of the polyisocyanate. is mentioned. Reaction temperature control is important, and in synthesis using polyol and polyisocyanate, it is preferable to control within the range of 50 to 130 ° C. When reacting polyamine and polyisocyanate, it is controlled within the range of 10 to 50 ° C. is preferred. The solid content is also important, and the solid content during the reaction is preferably 40 to 80% by mass. The reaction solvent is also important, and it is preferable to use ethyl acetate, n-propyl acetate and other ester-based organic solvents.

Further, the mass ratio of the urethane resin and the isocyanate curing agent (urethane resin:isocyanate curing agent) is preferably 99:1 to 60:40, preferably 98:2 to 65:35. More preferably, it is 95:5 to 70:30. When using a combination resin described below in addition to the urethane resin, the mass ratio of the total amount of the urethane resin and the combination resin to the isocyanate curing agent is preferably 99:1 to 60:40. , 95:5 to 70:30. This is because it is considered that within this range, the effects of cross-linking and adhesion to the substrate are good, sufficient resistance is exhibited in microwave ovens and boiling/retorting, and easy tearability is exhibited.

<Combined resin>
The glitter ink for forming the glitter print layer preferably contains a combined resin together with the urethane resin. Preferred embodiments of the combined resin are shown below.
For example, polyolefin-based resins such as polyethylene-based resins and chlorinated polypropylene-based resins, poly(meth)acrylic-based resins, polyvinyl chloride-based resins, polyvinyl acetate-based resins, vinyl chloride-vinyl acetate copolymers, polystyrene-based resins, Styrene-butadiene copolymer, vinylidene fluoride resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyvinyl butyral resin, polybutadiene resin, polyester resin, polyamide resin, alkyd resin, epoxy resin, unsaturated Fibers such as polyester-based resin, thermosetting poly(meth)acrylic-based resin, melamine-based resin, urea-based resin, phenol-based resin, xylene-based resin, maleic acid resin, nitrocellulose, ethyl cellulose, acetylbutyl cellulose, ethyloxyethyl cellulose, etc. base resin, rubber resin such as chlorinated rubber and cyclized rubber,
natural resins such as petroleum-based resins, rosin, and casein;
Among them, at least one selected from vinyl chloride copolymer resins, cellulose resins and rosin resins is preferable. A vinyl chloride copolymer resin is more preferable.

The vinyl chloride copolymer resin is preferably a vinyl chloride-vinyl acetate copolymer resin, a vinyl chloride-acrylic copolymer resin, or the like. The vinyl chloride copolymer resin preferably has a weight average molecular weight of 5,000 to 100,000, more preferably 5,000 to 50,000. The content of the structural unit derived from the vinyl acetate monomer in 100% by mass of the solid content of the vinyl chloride copolymer resin is preferably 70 to 95% by mass. Also, the glass transition temperature is preferably 50°C to 90°C. Also, the vinyl chloride copolymer resin preferably has a hydroxyl group, and preferably has a hydroxyl value of 10 to 200 mgKOH/g. This is because the reactivity with the isocyanate-based curing agent is improved, and the hydroxyl group is preferably derived from a vinyl alcohol unit-derived hydroxyl group or from an acrylic monomer having a hydroxyl group.

The mass ratio of the urethane resin to the vinyl chloride copolymer resin or other combined resin (urethane resin: combined resin) is preferably 95:5 to 30:70, more preferably 90:10 to 40:60. more preferred. This is because the adhesion to the base material, film physical properties, lamination strength, etc. are improved.

(Organic solvent)
The glitter ink may contain an organic solvent, water or other medium. Organic solvents include, but are not limited to, toluene and other aromatic organic solvents, methyl ethyl ketone and other ketone organic solvents, ethyl acetate, normal propyl acetate and other ester organic solvents, ethanol, isopropanol, normal propanol and other solvents. Alcohol-based organic solvents and the like are suitable. It may contain water, and when an organic solvent is used as a main medium, it is preferably contained in an amount of 10% by mass or less.

(Additive)
Glittering inks may further include fillers, stabilizers, plasticizers, antioxidants, light stabilizers such as UV absorbers, dispersants, thickeners, desiccants, lubricants, and electrifying agents, if necessary. Optional additives such as inhibitors, cross-linking agents, etc. can be added.

(ink layer)
The ink layer refers to a printed layer formed from a printing ink that does not have the bright pigment, and suitable examples include conventional screen inks, gravure inks, flexographic inks, inkjet inks, offset inks, and other printing inks. For example, JP-A-2005-298618, JP-A-2006-299136, JP-A-2009-249388, JP-A-2013-127038, JP-A-2017-19991, JP-A-2006-131844, Printing inks described in JP-A-2013-40248, JP-A-2007-231148, JP-A-2006-257302, etc. can be preferably used. However, it is not limited to these. Among them, gravure ink, flexographic ink and inkjet ink are preferred, and gravure ink and/or flexographic ink are more preferred.

<Base material>
The base material is preferably a plastic film, which plays a role as a base material on the outer layer side of the packaging material, and is composed of a light-transmitting material so that the glitter printed layer can be visually recognized from the outside.
Specifically, polyolefin resins such as polyethylene (PE) and polypropylene (PP), cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymer (AS) resins, acrylonitrile-butadiene-styrene copolymers (ABS) resin, poly (meth) acrylic resin, polycarbonate resin, polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer (EVOH), ethylene-vinyl ester copolymer saponified product, polyethylene terephthalate (PET) and poly Polyester resins such as butylene terephthalate (PBT) and polyethylene naphthalate (PEN), polyamide resins such as various nylons (Ny), polyurethane resins, acetal resins, cellulose resins, polyvinylidene chloride resins (PVDC), etc. is mentioned. The substrate may be uniaxially or biaxially oriented. Also, a composite film in which two or more of the above resin films are laminated may be used. Moreover, the form in which metal oxides, such as silica and an alumina, were vapor-deposited may be sufficient.

The substrate preferably has excellent heat resistance from the viewpoint of heating in a microwave oven and retort treatment. Polyester-based resins and/or polyamide-based resins are suitable as resins constituting the substrate having excellent heat resistance.
Specific examples of the base material having excellent heat resistance include a single polyester film, a single polyamide film such as nylon, and a composite film containing one or more of a polyester film and a polyamide film. Examples of the composite film include a coextruded stretched film composed of PET/Ny/PET and PET/Ny from the outer layer side. As the composite film, it is also preferable to combine one or more of polyester film and polyamide film with one or more of ethylene-vinyl alcohol copolymer film and polyvinylidene chloride film.

The thickness of the base material is not particularly limited, and can be appropriately set according to the use of the packaging material.

The substrate preferably has a total light transmittance of 85% or more, more preferably 90% or more, according to JIS K7361-1:1997. The haze of the base material is preferably 1.5% or less, more preferably 1.0% or less, and even more preferably 0.5% or less, according to JISK7136:2000.

<Formation of Glitter Print Layer and Ink Layer>
As a method for forming a glittering print layer and an ink layer, a printing method such as screen printing, offset printing, flexographic printing, dry offset printing, gravure printing, and inkjet printing is performed on the substrate using the glittering ink or the like. can be formed more suitably. Among them, gravure printing or flexographic printing is more preferable.

<Gravure printing>
(gravure version)
A gravure plate is a metal cylindrical plate, in which depressions are made for each color by engraving or etching/laser. There are no restrictions on the use of engraving and laser, and settings can be made arbitrarily according to the pattern. A line number of 100 to 300 lines is appropriately used, and the larger the number of lines, the finer the printing is possible. The thickness of the printed layer is preferably 0.1 μm to 100 μm.
(gravure printing machine)
In a gravure printing press, one printing unit includes the gravure plate and the doctor blade. There are many printing units, and printing units corresponding to organic solvent-based printing inks and graphic inks can be set, and each unit has an oven drying unit. Printing is carried out by rotary printing, which is a web printing method. The type of plate and the type of doctor blade can be selected as appropriate, and can be selected according to the specifications.

<Flexographic printing>
(flexographic plate)
Examples of plates used in flexographic printing include photosensitive resin plates utilizing ultraviolet curing with a UV light source and elastomer material plates using a direct laser engraving system. Regardless of the method of forming the image area of the flexographic plate, a plate having a screening ruling of 75 lpi or more is used. Any sleeve or cushion tape for attaching the plate can be used.
(Flexographic printing machine)
Flexographic printing machines include CI type multicolor flexographic printing machines, unit type multicolor flexographic printing machines, etc. As for the ink supply system, a chamber system and a two-roll system can be mentioned, and an appropriate printing machine can be used. can.

(Gas barrier layer)
A gas barrier layer can be provided anywhere between the substrate and the sealant, if desired. The gas barrier layer plays a role of blocking permeation of oxygen, water vapor, and the like between an object to be packaged by the packaging material and the external environment of the packaging material. In addition, it may also have a light-shielding property that blocks the transmission of visible light, ultraviolet rays, and the like. The gas barrier layer may be composed of only one layer, or may be composed of two or more layers.

Examples of the gas barrier layer (deposited film) include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron ( B), inorganic substances such as titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), etc., or vapor-deposited films formed of oxides thereof are suitable. Among these, inorganic oxides such as silicon oxide, aluminum oxide and magnesium oxide are preferable when the packaging material is for a microwave oven.
Examples of methods for forming a deposited film include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. law, etc.

The film thickness of the deposited film varies depending on the forming material, the required gas barrier performance, etc., but is generally preferably about 5 to 200 nm, more preferably 5 to 150 nm, further preferably 10 to 100 nm. In the case of inorganic oxides such as silicon oxides and aluminum oxides, the thickness is preferably about 5 to 100 nm, more preferably 5 to 50 nm, still more preferably 10 to 30 nm.

<Intermediate base material layer>
The packaging material of the present invention may have an intermediate substrate layer between the glitter printed layer and the sealant. The intermediate base material layer is a layer provided as necessary for the purpose of improving the strength and processability of the packaging material. Examples of the constituent material of the intermediate base material layer include a plastic film-like base material. As the base material, the same base material as described above can be used. In consideration of heating in a microwave oven and retort treatment, the intermediate base material layer preferably has excellent heat resistance in order to increase the heat resistance of the packaging material. A polyester base material, a polyamide base material, or the like is preferably used.

<Adhesive layer>
In the packaging material, each component layer is laminated via an adhesive layer from the viewpoint of improving the bonding strength between the layers. The adhesive layer can be formed by a method using a known adhesive for dry lamination.
Examples of dry laminate adhesives include polyvinyl acetate adhesives, polyacrylate adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives, cellulose adhesives, polyester adhesives, and polyamide adhesives. Adhesives, polyimide adhesives, amino resin adhesives such as urea resins and melamine resins, phenol resin adhesives, epoxy adhesives, polyurethane adhesives (for example, cured products of polyols and isocyanate compounds), reactions Examples include (meth)acrylic acid-based adhesives, rubber-based adhesives such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber, silicone-based adhesives, and inorganic adhesives such as alkali metal silicate and low-melting glass.
The adhesive is formed by applying it to the printed layer, sealant or intermediate substrate layer and then laminating each layer, substrate or sealant. The coating film thickness is preferably 0.5 to 5 μm, and more preferably 1 to 4 μm.

<Sealant>
The sealant has a surface on the inner layer side that comes into direct contact with the object to be packaged and plays a role of protecting the object to be packaged. It is preferable that the innermost layer of the sealant has a heat-sealing property in order to make the packaging material bag-like. Materials constituting the sealant include, for example, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer, and propylene. Examples include polyolefin resins such as homopolymers and ethylene-propylene copolymers, and one or more of these resins can be used. The sealant may be composed of a single layer or multiple layers of two or more layers. It should be noted that the sealant is preferably a non-stretched film made of the resin described above in order to suppress shrinkage during heat sealing.

From the viewpoint of heating in a microwave oven or retort, the sealant is preferably composed of a resin with excellent heat resistance in order to increase heat resistance. Specifically, propylene-based resins such as polypropylene and ethylene-propylene copolymer. and HDPE are preferred.

The thickness of the sealant is not particularly limited, and is appropriately set according to the use of the packaging material and the type and properties of the object to be packaged, but it is usually preferably 10 to 200 μm. In the case of pouches (especially retort pouches), the thickness of the sealant is preferably 20-150 μm, more preferably 30-100 μm.

(Method for manufacturing packaging material)
The packaging material of the present invention is a method for producing a packaging material having at least a substrate, a glittering print layer, an adhesive layer and a sealant in this order, wherein the glittering printing layer comprises a glittering pigment, a urethane resin and a weight-average molecular weight A step of forming a glitter ink containing an isocyanate curing agent of 800 to 8000 on the substrate by gravure printing or flexographic printing. Further, if necessary, an ink layer may be arbitrarily formed on the glitter printed layer to form a printed layer to improve the design. The adhesive layer may be formed by applying it on the printed layer, or may be formed by applying it to the sealant.
A preferred mode is, for example, a mode in which an adhesive is applied on the printed layer, and then a sealant is attached. In addition, when the packaging material further has an intermediate base material layer, there is an aspect including a step of bonding the printed layer and the intermediate base material layer together with an adhesive, and further bonding the intermediate base material layer and the sealant. preferable. Note that the configuration is arbitrary and not particularly limited.
The packaging material thus obtained is cut to a predetermined size and heat-sealed at the edges with the sealants aligned with each other to form a bag. The heat sealing temperature is preferably 50 to 250°C, more preferably 80 to 180°C. The heat sealing pressure may be 1 to 5 kg/cm ² or the like. A single packaging material may be folded and heat-sealed at the edges, or two or more packaging materials may be heat-sealed. Moreover, the bag made of the packaging material may be one in which all the openings are heat-sealed after the contents are packaged.

(Boiled retort)
Usually, packaging materials such as pouches are subjected to high-temperature heating (pressurization) treatment for the purpose of sterilizing after sealing the contents in advance in order to extend the expiration date, and this is called retort. The heating time required to kill bacteria decreases logarithmically with increasing temperature. On the other hand, boiling sterilization is a method of sterilizing food by placing it in hot water after packaging.
The general method is to put the food in a basket, immerse it in a hot water bath at a specified temperature, and take it out after a certain period of time. This means that it can be processed in Retort is generally performed at 120-130°C,
Boil is about 100°C. Therefore, if the packaging material has heat resistance in retort, it also has resistance in boiling.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples. Parts and % in the present invention represent parts by mass and % by mass unless otherwise specified. Examples 1 to 9 are Reference Examples 1 to 9.

(hydroxyl value)
It was obtained according to JISK0070.
(acid value)
It was obtained according to JISK0070.
(amine value)
The amine value was obtained in mg of potassium hydroxide equivalent to the equivalent of hydrochloric acid required to neutralize the amino groups contained in 1 g of the resin according to JIS K0070 according to the following method.
0.5 to 2 g of the sample was accurately weighed (sample solid content: Sg). 50 mL of a mixed solution of methanol/methyl ethyl ketone=60/40 (mass ratio) was added to the accurately weighed sample to dissolve the sample. Bromophenol blue was added to the resulting solution as an indicator, and the resulting solution was titrated with a 0.2 mol/L ethanolic hydrochloric acid solution (potency: f). The point at which the color of the solution changed from green to yellow was defined as the end point, and the titration amount (AmL) at this time was used to determine the amine value by the following (formula 2).
(Formula 2) Amine value = (A x f x 0.2 x 56.108) / S [mgKOH/g]

(Weight average molecular weight Mw, number average molecular weight Mn and molecular weight distribution Mw/Mn)
The weight average molecular weight Mw, the number average molecular weight Mn and the molecular weight distribution Mw/Mn are measured using a GPC (gel permeation chromatography) device (HLC-8220 manufactured by Tosoh Corporation), and polystyrene is used as a standard substance. It was obtained as a converted molecular weight. Measurement conditions are shown below.
Column: The following columns were connected in series and used.
TSKgelSuperAW2500 manufactured by Tosoh Corporation
TSKgelSuperAW3000 manufactured by Tosoh Corporation
TSKgelSuperAW4000 manufactured by Tosoh Corporation
TSK gelguard column Super AWH manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Measurement conditions: Column temperature 40°C
Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min

[Synthesis Example 1] (Synthesis of urethane resin 1)
A condensate of 3-methyl-1,5-pentanediol (hereinafter referred to as "MPD") and adipic acid (hereinafter referred to as "AA") having a number average molecular weight of 2000 in a reaction vessel equipped with stirring blades under a nitrogen gas atmosphere. 90 parts of polyester polyol (polyol P-2010 manufactured by Kuraray Co., Ltd.), 10 parts of polypropylene glycol having a number average molecular weight of 2000 (hereinafter "PPG"), 1,3-propanediol (hereinafter "1,3-PD") .5 parts, 31 parts of isophorone diisocyanate (hereinafter "IPDI"), and 33.1 parts of propyl acetate were reacted under a nitrogen stream at 80°C and a stirring speed of 150 rpm for 5 hours to obtain a solvent solution of a terminal isocyanate urethane prepolymer. . Next, in another reaction vessel equipped with stirring blades, 11 parts of isophoronediamine (hereinafter "IPDA"), 1.5 parts of iminobispropylamine (hereinafter "IBPA"), and 0.8 part of 2-ethanolamine (hereinafter "2EtAm") were added. 307.1 parts of a mixed solvent of propyl acetate/isopropanol (hereinafter "IPA") = 60/40 were rapidly stirred at a stirring speed of 180 rpm and maintained at 40°C to obtain a terminal isocyanate prepolymer solution. was added dropwise at 40° C. over 60 minutes and then reacted at 80° C. for 1 hour. After completion of the reaction, the solid content was adjusted to 30% by mass with a propyl acetate/IPA mixed solvent to obtain a urethane resin 1 solution.

(Urethane resin 1)
Amine value: 6.5 mgKOH/g
Hydroxyl value: 5.0mgKOH/g
Acid value: 0.1mgKOH/g
Glass transition temperature: -40°C
Weight average molecular weight: 50000
Mw/Mn: 2.7

[Synthesis Example 2] (Synthesis of urethane resin 2)
In a nitrogen gas atmosphere, in a reaction vessel with stirring blades, 90 parts of polyester polyol (polyol P-2010 manufactured by Kuraray Co., Ltd.) which is a condensation product of MPD and AA, 10 parts of PPG, 1.5 parts of 1,3-PD, 31 parts of IPDI and 33.1 parts of propyl acetate were reacted under a nitrogen stream at 50° C. and a stirring speed of 50 rpm for 8 hours to obtain a solvent solution of a terminal isocyanate urethane prepolymer. Next, 11 parts of IPDA, 1.5 parts of IBPA, 0.8 parts of 2EtAm, and 307.1 parts of a mixed solvent of propyl acetate/IPA) = 60/40 are stirred at a stirring speed of 80 rpm and maintained at 80°C to obtain The isocyanate-terminated prepolymer solution was added dropwise at 80°C over 60 minutes and then reacted at 80°C for 1 hour. After completion of the reaction, the solid content was adjusted to 30% by mass with a propyl acetate/IPA mixed solvent to obtain a urethane resin 2 solution.

(Urethane resin 2)
Amine value: 6.0 mgKOH/g
Hydroxyl value: 5.0mgKOH/g
Acid value: 0.1mgKOH/g
Glass transition temperature: -40°C
Weight average molecular weight: 60000
Mw/Mn: 5.6

[Synthesis Example 3] (Synthesis of urethane resin 3)
Under a nitrogen gas atmosphere, 100 parts of polypropylene glycol having a number average molecular weight of 2000, 1.5 parts of 1,3-PD, 31 parts of IPDI, and 33.1 parts of propyl acetate are stirred at 80° C. under a nitrogen stream in a reactor equipped with stirring blades. A reaction was carried out at a speed of 150 rpm for 5 hours to obtain a solvent solution of a terminal isocyanate urethane prepolymer. Next, in another reactor equipped with stirring blades, 11 parts of IPDA, 1.5 parts of IBPA, 0.8 parts of 2EtAm, and 307.1 parts of a mixed solvent of propyl acetate/IPA = 60/40 were rapidly stirred at a stirring speed of 180 rpm, Maintained at 40°C, the resulting isocyanate terminated prepolymer solution was added dropwise at 40°C over 60 minutes and then reacted at 80°C for 1 hour. After completion of the reaction, the solid content was adjusted to 30% by mass with a propyl acetate/IPA mixed solvent to obtain a urethane resin 1 solution.

(Urethane resin 3)
Amine value: 6.0 mgKOH/g
Hydroxyl value: 5.0mgKOH/g
Acid value: 0.1mgKOH/g
Glass transition temperature: -70°C
Weight average molecular weight: 45000
Mw/Mn: 2.6

[Synthesis Example 4] (Synthesis of Curing Agent 1)
In a nitrogen gas atmosphere, 15 parts of trimethylolpropane, 60.3 parts of toluene-2,4-diisocyanate, and 32.3 parts of previously dehydrated ethyl acetate were stirred at 50° C. and 150 rpm in a reactor equipped with stirring blades. A curing agent 1 having a solid content of 70% by mass was obtained by reacting at a high speed for 3 hours.
(Curing agent 1 (adduct type))
Weight average molecular weight: 1200
Mw/Mn: 2.5

[Synthesis Example 5] (Synthesis of Curing Agent 2)
In a nitrogen gas atmosphere, 15 parts of trimethylolpropane, 29.8 parts of toluene-2,4-diisocyanate, and 99.3 parts of previously dehydrated ethyl acetate were stirred at 50° C. and 150 rpm in a reactor equipped with stirring blades. A curing agent 2 having a solid content of 70% by mass was obtained by reacting at a high speed for 3 hours.
(Curing agent 2 (adduct type))
Weight average molecular weight: 2500
Mw/Mn: 3.3

[Synthesis Example 6] (Synthesis of Curing Agent 3)
15 parts of ditrimethylolpropane, 39.7 parts of toluene-2,4-diisocyanate and 23.4 parts of ethyl acetate were reacted at 100° C. for 3 hours at a stirring speed of 100 rpm in a reaction vessel equipped with stirring blades under a nitrogen gas atmosphere. A curing agent 3 having a solid content of 70% by mass was obtained.
(Curing agent 3 (adduct type))
Weight average molecular weight: 3500
Mw/Mn: 5.5

[Example 1] (Production of packaging material 1)
On the entire surface of the gas barrier layer of a 12 μm-thick plastic film (silica-deposited polyethylene terephthalate film, Techbarrier VX, manufactured by Mitsubishi Chemical Corporation), the following glitter ink S1 was gravure printed and dried to give a dry film thickness of 1.5 μm. A printed layer was formed. Next, white ink (Rio Alpha R manufactured by Toyo Ink Co., Ltd.
631 white) was gravure printed and dried to form a white printed layer with a dry film thickness of 1.5 μm. Next, a urethane-based adhesive (TM-250HV/CAT-RT86L-60 manufactured by Toyo-Morton Co., Ltd.) is applied on the white printed layer and dried to form a first adhesive layer with a thickness of 2.5 μm. The first adhesive layer and the intermediate substrate layer (stretched nylon (Ny), thickness 15 μm) were dry-laminated.
Next, a urethane-based adhesive (TM-250HV/CAT-RT86L-60 manufactured by Toyo-Morton Co., Ltd.) is applied to the sealant (CPP, unstretched polypropylene, thickness 70 μm) and dried to form an adhesive layer with a thickness of 2.5 μm. formed. Next, the sealant having the second adhesive layer formed thereon was dry-laminated on the surface of the intermediate base material layer to obtain the packaging material 1 of Example 1.
The packaging material 1 of Example 1 includes, from the outer layer side, a silica vapor deposition base material, a printed layer (bright printed layer, white printed layer), a first adhesive layer, an intermediate base material layer, a second adhesive layer and I have the sealant in that order.

<Glitter ink S1>
・ 15 parts by mass of a composition containing metal flakes and mineral spirits (solid content: 12 parts by mass)
(The content of metal flakes is 80% by mass)
(Metal flakes: non-leafing type aluminum flakes with surface adsorption of oleic acid, average particle diameter 10 μm, average thickness 0.07 μm)
・ Yellow organic pigment 1 3 parts by mass (CI Pigment Yellow 83 average particle size: 150 nm)
・ Inorganic fine particles 1 part by mass (silica particles, average primary particle size: 20 nm)
・Binder resin 50 parts by mass (solid content 15 parts by mass)
(Urethane resin 1 above)
・Organic solvent 78 parts by mass (mixed solvent of propylene glycol monomethyl ether, normal propyl acetate, ethyl acetate and isopropanol)
・Isocyanate curing agent 3 parts by mass (solid content 2.1 parts by mass)
(Curing agent 1 above)

[Examples 2 to 12] (Production of packaging materials 2 to 12)
Packaging materials 2 to 12 of Examples 2 to 12 were obtained in the same manner as in Example 1, except that the raw materials and the bright inks having the mixing ratios shown in Table 1 were used. Abbreviations in Table 1 represent the following.・ White pearl pigment: mica coated with titanium oxide Average particle size 12 μm Solid content 100% by mass
・ TLA-100: Asahi Kasei isocyanurate type isocyanate curing agent Weight average molecular weight: 1300 Mw / Mn: 2.4 Solid content 70% by mass
・ E402-80B: isocyanate curing agent manufactured by Asahi Kasei Co., Ltd. Weight average molecular weight: 4000
Mw/Mn: 3.4 solid content 70% by mass
・ D-178NL: Mitsui Chemicals isocyanate curing agent Weight average molecular weight: 600 Solid content 70% by mass

[Comparative Examples 1 to 4] (Production of packaging materials 15 to 18)
Packaging materials 15 to 18 of Comparative Examples 1 to 4 were obtained in the same manner as in Example 1, except that the raw materials and the bright inks having the mixing ratios shown in Table 1 were used. Abbreviations in Table 1 represent the following.・ White pigment: Titanium oxide CR-90 manufactured by Ishihara Sangyo Co., Ltd. Solid content 100%

(measurement and evaluation)
The following measurements and evaluations were performed on the packaging materials of Examples and Comparative Examples. Table 1 shows the results.

<Designability>
Under the illumination of a three-wavelength fluorescent lamp, the packaging materials of Examples and Comparative Examples were observed from a direction slightly shifted from the specular reflection direction of the fluorescent lamp, and the aesthetic appearance due to gloss was evaluated.
A high level of metallic luster can be felt, and 4 points indicate that the aesthetic appearance based on metallic luster is extremely excellent, and 2 points indicate that neither can be said to be either. Twenty subjects performed evaluation, with 1 point being assigned to one that could not be said, and the average score was calculated.
<Evaluation Criteria>
A: Average score of 3.5 or more B: Average score of more than 3 and less than 3.5 C: Average score of more than 2.5 and less than 3 D: Average score of less than 2.5

<microwave resistance>
For the packaging materials obtained in the above examples and comparative examples, the contents were made into a 1:1:1 soup (ketchup: vinegar: water = 1:1:1 in mass ratio) and heated in a microwave oven at 600 W for 3 minutes. Appearance was evaluated.
A: No change was observed in appearance. (Good)
B: No change was observed in appearance, but slight deformation was observed. (somewhat good)
C: Laminate float was observed only at one place in the appearance. (Practical)
D: A plurality of laminate lifts were observed in the appearance. (defective)
It should be noted that the practical evaluations are A, B and C.
All of the above packaging materials were found to expand due to steam during the heating process in the microwave oven, but no sparks or holes were observed.

<Retort resistance>
The packaging materials obtained in the above Examples and Comparative Examples were subjected to retort treatment at 120° C. for 30 minutes with the contents as 1:1:1 soup (ketchup: vinegar: water = 1:1:1 in mass ratio). Changes in appearance were visually evaluated according to the following criteria.
A: No change was observed in appearance. (Good)
B: No change was observed in appearance, but slight deformation was observed. (somewhat good)
C: Laminate float was observed only at one place in the appearance. (Practical)
D: A plurality of laminate lifts were observed in the appearance. (defective)
It should be noted that the practical evaluations are A, B and C.

<Easy tearability>
For the packaging materials obtained in the above examples and comparative examples, after conducting the above microwave oven test, samples were prepared according to JISK7128-1: 1998 and evaluated by resistance when torn with a 201 universal tensile tester manufactured by Intesco. bottom.
[Evaluation criteria]
A: less than 1.5N (good)
B: 1.5 N or more and less than 2.0 N (slightly good)
C: 2.0 N or more and less than 2.5 N (practical)
D: 2.5 N or more (defective)
It should be noted that the practical evaluations are A, B and C.

[Example 13] (Production of packaging material 13)
The glitter ink S1 was gravure-printed on the entire surface of the gas barrier layer of a 12 μm-thick plastic film (silica-deposited polyamide (nylon) film, Techbarrier NR manufactured by Mitsubishi Chemical Corporation) and dried to form a dry film having a thickness of 1.5 μm. A glitter printed layer was formed. Next, white ink (Rio Alpha R631 White, manufactured by Toyo Ink Co., Ltd.) was gravure printed on the entire surface of the glitter printed layer and dried to form a white printed layer having a dry film thickness of 1.5 μm. Next, an adhesive (TM-250HV/CAT-RT86L-60 manufactured by Toyo-Morton Co., Ltd.) is applied on the white printed layer and dried to form a urethane-based adhesive layer having a thickness of 2.5 μm. A packaging material 13 of Example 13 was obtained by dry laminating a sealant (CPP, unstretched polypropylene, thickness 70 μm) thereon.
The packaging material 13 has, from the outer layer side, a silica deposition base material, a printed layer (a glitter printed layer, a white printed layer), an adhesive layer and a sealant in this order. When this packaging material was evaluated in the same manner as in the above examples, designability: A, microwave oven resistance: A, retort resistance: B, and tearability: A were obtained.

[Example 14] (Production of packaging material 14)
The glitter ink S10 was gravure-printed on the entire surface of the gas barrier layer of a 12 μm-thick plastic film (silica-deposited polyamide (nylon) film, Techbarrier NR manufactured by Mitsubishi Chemical Corporation) and dried to form a dry film thickness of 1.5 μm. A glitter printed layer was formed.
Next, white ink (Rio Alpha R631 White, manufactured by Toyo Ink Co., Ltd.) was gravure printed on the entire surface of the glitter printed layer and dried to form a white printed layer having a dry film thickness of 1.5 μm. Next, an adhesive (TM-250HV/CAT-RT86L-60 manufactured by Toyo-Morton Co., Ltd.) is applied on the white printed layer and dried to form a urethane-based adhesive layer having a thickness of 2.5 μm. A packaging material 14 of Example 14 was obtained by dry-laminating a sealant (CPP, unstretched polypropylene, thickness 70 μm) thereon.
The packaging material 14 has, from the outer layer side, a silica deposition base material, a printed layer (a glitter printed layer, a white printed layer), an adhesive layer and a sealant in this order. When this packaging material was evaluated in the same manner as in the above examples, designability: A, microwave oven resistance: A, retort resistance: B, and tearability: A were obtained.

From the above, it was found that the packaging material of the present invention is a packaging material that is excellent in microwave oven resistance and retort resistance and has easy tearability even after the heating. If the isocyanate-based curing agent does not have a predetermined weight-average molecular weight or does not contain a curing agent, it is inferior in tearability, etc., and if it does not contain a bright pigment, the design is lacking. .

Claims (9)

A packaging material having, in order, at least a substrate, a glitter printing layer, an adhesive layer and a sealant,
The glitter print layer contains a glitter pigment and a urethane resin, and is crosslinked with an isocyanate curing agent,
The isocyanate curing agent has a weight average molecular weight of 800 to 8000 ,
The packaging material , wherein the luster pigment includes a pearl pigment, and the pearl pigment has an average particle size of 2 to 200 μm . The packaging material according to claim 1, wherein the mass ratio of the urethane resin and the isocyanate curing agent is 99:1 to 60:40. The packaging material according to claim 1 or 2, wherein the isocyanate curing agent has a molecular weight distribution (Mw/Mn) of 1.5 to 5. The packaging material according to any one of claims 1 to 3, wherein the urethane resin contains polyester-derived structural units. The packaging material according to any one of claims 1 to 4, wherein the urethane resin has a molecular weight distribution (Mw/Mn) of 1.5 to 5. The packaging material according to any one of claims 1 to 5, wherein the base material is a polyester base material or a polyamide base material. The packaging material according to any one of claims 1 to 6, wherein the luster pigment further contains scale aluminum. The packaging material according to any one of claims 1 to 7, which is for a microwave oven or a boil/retort pouch. A method for producing a packaging material having, in order, at least a substrate, a glitter print layer, an adhesive layer and a sealant,
The glitter printing layer comprises a glitter ink containing a glitter pigment containing a pearl pigment having an average particle diameter of 2 to 200 μm , a urethane resin, and an isocyanate curing agent having a weight average molecular weight of 800 to 8000. A method of manufacturing a packaging material, comprising forming by printing or flexographic printing.