JP2024025822A - Packaging material, packaging bag and method for manufacturing packaging material - Google Patents

Abstract

To provide a packaging material and a packaging bag which are excellent in piercing resistance, blocking resistance, heat resistance and glossiness while maintaining heat sealability and water vapor barrier property.SOLUTION: There are provided a packaging material which sequentially has a heat seal layer, a paper base material, a printing layer and a surface protective layer, wherein the heat seal layer contains a polyethylene resin, and the surface protective layer contains a cellulose-based resin (A) and a plasticizer; a package using the packaging material; and a manufacturing method which can provide the packaging material.SELECTED DRAWING: None

Description

The present invention relates to a packaging material, a packaging bag, and a manufacturing method capable of providing the packaging material, which has excellent puncture resistance, blocking resistance, heat resistance, and gloss while maintaining heat-sealing properties and water vapor barrier properties.

In recent years, it has become common for product packages and other packaging to be printed for decoration or surface protection. Furthermore, the quality of printing, such as the design, beauty, and luxury of printed matter, promotes consumers' desire to purchase the printed matter, and has great industrial value.

Conventionally, packages have mainly been constructed using laminate packaging materials using plastic films. For example, Patent Document 1 describes an invention relating to a laminate packaging material that includes a base material, a printed layer, an adhesive layer, and a sealant layer, and in which a biomass resin is used for the printed layer and the adhesive layer. However, laminated packaging materials use a large amount of plastic film made of petroleum-derived materials, and from the viewpoints of reducing plastics, being environmentally friendly, and being carbon neutral, there is a desire to switch to paper (paper-based packaging materials). Technology is being developed.

For example, Patent Document 2 describes an example in which a paper base material is used as a part of a packaging material, including a resin layer, a printed layer, a paper base material layer, a metal vapor deposited film layer, a gas barrier film layer, and a heat-sealable resin layer. An invention is described that relates to a paper laminate having sequential properties. However, the resin layer formed on the printing layer is made of low density polyethylene or the like in order to provide heat sealability. Therefore, the hardness, toughness, and surface smoothness of the coating film are insufficient, and there are problems with puncture resistance, blocking resistance, heat resistance, and surface gloss. Furthermore, in addition to the above-mentioned problems, paper packaging materials are required to have water vapor barrier properties.

For example, Patent Document 3 describes an invention relating to a packaging material that sequentially has a surface protective layer, a printed layer, a paper base layer, and a resin layer, and the surface protective layer contains nitrocellulose. However, since the above-mentioned surface protective layer is formed only from nitrocellulose, the surface protective layer lacks smoothness, tack breakage, and toughness, and has problems with gloss, blocking resistance, and heat resistance. .

That is, a packaging material using a paper base material that maintains heat-sealing properties and water vapor barrier properties while exhibiting excellent puncture resistance, blocking resistance, heat resistance, and gloss has not yet been found.

Japanese Patent Application Publication No. 2018-051796 Japanese Patent Application Publication No. 2006-256198 JP2020-55171A

An object of the present invention is to provide a packaging material and a packaging bag that have excellent puncture resistance, blocking resistance, heat resistance, and gloss while maintaining heat sealability and water vapor barrier properties.

As a result of extensive research into the above-mentioned problems, the present inventors have discovered that the above-mentioned problems can be solved by using the packaging material described below, and have accomplished the present invention.

A packaging material according to one aspect of the present invention is a packaging material having a heat-sealing layer, a paper base material, a printing layer, and a surface protective layer in this order, wherein the heat-sealing layer contains a polyethylene resin, and the surface protective layer is characterized by containing a cellulose resin (A) and a plasticizer.

The packaging material according to one aspect of the present invention is characterized in that the surface protective layer has a gloss value of 25 or more as measured according to JIS Z 8741.

The packaging material according to one aspect of the present invention is characterized in that the viscosity of the cellulose resin (A) as measured by JIS K 6703 satisfies any of the following (1) to (3).
(1) The viscosity at a solution concentration of 12.2% by mass is 1.5 to 16 seconds.
(2) The viscosity at a solution concentration of 20.0% by mass is 3.0 to 40 seconds.
(3) The viscosity at a solution concentration of 25.0% by mass is 0.1 to 22 seconds.

The packaging material according to one aspect of the present invention is characterized in that it further includes a barrier layer.

A packaging material according to one aspect of the present invention is characterized in that the cellulose resin (A) includes a nitrocellulose resin.

A packaging material according to one aspect of the present invention is characterized in that the printing layer contains a cellulose resin (B).

In the packaging material according to one aspect of the present invention, the printing layer further includes at least one type selected from the group consisting of polyamide resin, urethane resin, styrene-maleic acid copolymer resin, styrene-allyl alcohol copolymer resin, and acrylic resin. It is characterized by containing the following resin (C).

The packaging material according to one aspect of the present invention is characterized in that the mass ratio of cellulose resin (B) to resin (C) is 99:1 to 30:70.

The packaging material according to one aspect of the present invention is characterized in that the surface protective layer further contains a polyamide resin.

The packaging material according to one aspect of the present invention is characterized in that the mass ratio of cellulose resin (A) to polyamide resin is 99:1 to 15:85.

A packaging material according to one aspect of the present invention is characterized in that the surface protective layer further contains amide wax.

A packaging bag according to one aspect of the present invention is characterized by being formed from the above packaging material.

A method for manufacturing a packaging material according to one aspect of the present invention is a method for manufacturing a packaging material having a heat seal layer, a paper base material, a printing layer, and a surface protection layer in this order,
a process of gravure printing a printing ink on one side of a paper base material to form a printing layer;
A step of gravure printing an overcoat agent containing a cellulose resin (A) and a plasticizer onto the printing layer to form a surface protective layer, and a step of coating the other side of the paper base material with a molten polyethylene resin. forming a heat-sealing layer;
It is characterized by including.

According to the present invention, it is possible to provide a packaging material and a packaging bag that have excellent puncture resistance, blocking resistance, heat resistance, and gloss while maintaining heat sealability and water vapor barrier properties.

<Packaging material>
The packaging material in the present invention has a heat-sealing layer, a paper base material, a printing layer, and a surface protection layer in this order, the heat-sealing layer containing a polyethylene resin, and the surface protection layer containing a cellulose resin (A). and a plasticizer. With the above configuration, the packaging material has good hardness, flexibility, toughness, and surface smoothness, and can exhibit excellent puncture resistance, blocking resistance, heat resistance, and gloss.
The embodiments of the present invention will be described in detail below, but the explanation of the constituent elements described below is an example of the embodiments of the present invention, and the present invention is not limited to these contents unless it exceeds the gist thereof. .
In this specification, "parts" and "%" represent "parts by mass" and "% by mass" unless otherwise specified. In addition, the packaging material may be simply abbreviated as a "laminate", but it has the same meaning. Moreover, "solid content" represents the total mass of nonvolatile components.
Further, in this specification, "printing ink" refers to an ink containing a coloring agent such as a pigment. On the other hand, "overcoat agent" refers to an agent that does not contain a colorant such as a pigment, but does not exclude an agent that contains a small amount of colorant that is unintentionally mixed.

<Surface protective layer>
The surface protective layer in the present invention contains a cellulose resin (A) and a plasticizer.
The surface protective layer can be formed using an overcoat agent containing cellulose resin (A) and a plasticizer. The method for forming the surface protective layer can be appropriately selected from known printing methods such as a gravure printing method and a flexographic printing method, and preferably a gravure printing method. The viscosity of the overcoat agent is preferably 20 to 200 mPa·s from the viewpoint of printability and the like.
The thickness of the surface protective layer is preferably 0.3 to 10 μm, more preferably 1 to 7 μm.

[Overcoat agent]
The overcoat agent contains a cellulose resin (A) and a plasticizer, and may further contain an organic solvent.

(Cellulose resin (A))
As the cellulose resin (A), cellulose ester resin is suitable. Cellulose ester resin is a resin obtained by esterifying cellulose derived from non-edible plants such as wood fibers and cotton, and examples thereof include cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and nitrocellulose. The cellulose ester resin is preferably nitrocellulose from the viewpoint of heat resistance.

The cellulose resin (A) preferably has a viscosity that satisfies any of the following (1) to (3) as measured in accordance with JIS K 6703-1995. The above viscosity is the time it takes for a steel ball to fall through the isopropanol solution of the cellulose resin (A) (steel ball falling time (seconds)).
(1) The viscosity at a solution concentration of 12.2% is 1.5 to 16 seconds.
(2) The viscosity at a solution concentration of 20.0% is 3.0 to 40 seconds.
(3) The viscosity at a solution concentration of 25.0% is 0.1 to 22 seconds.
Among these, it is preferable that the viscosity of the cellulose resin (A) satisfies the above (3). In (3) above, the viscosity at a solution concentration of 25.0% is preferably 0.5 to 15 seconds, more preferably 0.5 to 9 seconds. When the viscosity is within the above range, surface smoothness and toughness are imparted to the surface protective layer, and gloss and heat resistance are improved.

The weight average molecular weight (Mw) of the cellulose resin (A) is preferably 5,000 to 200,000, more preferably 10,000 to 100,000, and even more preferably 10,000 to 80,000. . When it is within the above range, the hardness and flexibility of the coating film can be achieved at the same time, and the puncture resistance, blocking resistance, and adhesion between the surface protective layer and the printed layer are improved.
Further, the glass transition temperature of the cellulose resin (A) is preferably 80°C to 160°C. When it is within the above range, the surface protective layer can have both hardness and flexibility, and the puncture resistance, blocking resistance, and adhesion between the surface protective layer and the printed layer are improved.

The weight average molecular weight can be measured, for example, by GPC (gel permeation chromatography), and can be determined as a converted molecular weight using polyethylene glycol as a standard substance. Examples of the measuring device include a GPC device such as Shodex GPC-104 manufactured by Showa Denko, and examples of the column include Shodex LF-404 manufactured by Showa Denko. Examples of the detector include RI (differential refractometer), and the measurement temperature is preferably a column temperature of 20 to 50°C. Examples of the eluent include tetrahydrofuran, and the flow rate is generally in the range of 0.2 to 5.0 mL/min.

The glass transition temperature can be measured using, for example, a differential scanning calorimeter (DSC measuring device, "DSC-60A" manufactured by Shimadzu Corporation), and the temperature at the inflection point in the baseline shift is used as the glass transition temperature. be able to. The measurement is preferably carried out under a nitrogen atmosphere, the measurement temperature range is -100 to 200°C, and the temperature increase rate is preferably 1 to 5°C/min.

When the cellulose resin (A) is nitrocellulose, the nitrogen content of the nitrocellulose is preferably 10 to 13% by mass, more preferably 10.7 to 12.2% by mass based on the total solid content of nitrocellulose. %. When it is within the above range, the surface protective layer can have both hardness and flexibility, and the puncture resistance, blocking resistance, and adhesion between the surface protective layer and the printed layer are improved.

The weight average molecular weight of nitrocellulose is preferably 3,000 to 40,000, more preferably 3,000 to 25,000, and more preferably 5,000 to 15,000. When it is within the above range, the surface protective layer can have both hardness and flexibility, and the puncture resistance, blocking resistance, and adhesion between the surface protective layer and the printed layer are improved.
Examples of commercially available nitrocellulose include those manufactured by NOBEL (DHX3-5, DHX5-10, DHX8-13).

(Plasticizer)
The plasticizer, when added in a small amount, has the role of accelerating the volatility of the organic solvent, imparting flexibility to the surface protective layer, and increasing adhesion to the printing layer.
As the plasticizer, in addition to the cellulose resin (A), those having excellent compatibility with other resin components contained in the surface protective layer and having low volatility are suitably used, such as citric acid ester, phthalic acid ester, etc. It is preferable that at least one selected from esters, phosphoric acid esters, trimetic acid esters, aliphatic dibasic acid esters, glycol ethers, sulfonic acid amide systems, and castor oil is included.

As the citric acid ester, acetyl trialkyl citrate such as triethyl citrate, acetyl triethyl citrate, tri-n-butyl citrate, acetyl tri-n-butyl citrate, and 2-ethylhexyl acetyl citrate is preferred. The alkyl group preferably has 2 to 12 carbon atoms. Among them, acetyl tri-n-butyl citrate, acetyl triethyl citrate, etc. are preferably used.
Examples of phthalate esters include dialkyl phthalates such as bis(2-ethylhexyl) phthalate, diisononyl phthalate, diisodecyl phthalate, and diundecyl phthalate, and the alkyl group preferably has 2 to 12 carbon atoms. preferable. Among them, diisononyl phthalate, diisodecyl phthalate, and the like are preferably used.
As the phosphoric acid ester, phosphoric acid esters such as tricresyl phosphate, triphenyl phosphate, and tributyl phosphate are preferably mentioned, and tributyl phosphate is more preferable.
As the trimetate ester, trialkyl trimellitates such as tri-2-ethylhexyl trimetate, trioctyl trimetate, and triisononyl trimetate are preferred. The alkyl group preferably has 2 to 12 carbon atoms. Among them, tri-2-ethylhexyl trimetate and the like are preferably used.
The aliphatic dibasic acid ester is preferably a fatty acid dialkyl ester, and the alkyl group preferably has 2 to 12 carbon atoms. Examples of fatty acid dialkyl esters include adipate esters and sebacate esters, among which bis(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, bis(2-ethylhexyl) sebacate, and diisononyl sebacate. , diisodecyl sebacate is preferably used.
Preferred examples of the sulfonic acid amide include N-butylbenzenesulfonic acid amide and N-ethyltoluenesulfonic acid amide.
In addition, examples of glycol ethers include diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, etc.

The surface protective layer in the present invention preferably contains at least one plasticizer selected from the group consisting of castor oil, glycol ether, aliphatic dibasic acid ester, and citric acid ester, and glycol ether is more preferred.
The content of the plasticizer in the surface protective layer is preferably 0.1 to 15% by mass, more preferably 3 to 12% by mass, and particularly preferably 5 to 9% by mass. When it is within the above range, the surface protective layer can have both hardness and toughness, and the blocking resistance and heat resistance are improved.

The surface protective layer of the packaging material of the present invention preferably has a gloss value of 25 or more. It is more preferably 30 or more, still more preferably 35 or more, particularly preferably 40 or more. The above gloss value is a 60 degree gloss value (Gs(60)) measured in accordance with JIS Z 8741:1997.
Note that the above gloss value does not refer to the gloss level (mirror reflection) of a metal layer such as an aluminum vapor deposited layer on the inside of the packaging material, but refers to the gloss value of the outermost surface protective layer.
From the viewpoint of keeping the gloss value of the surface protective layer within the above range, it is preferable that the surface protective layer further contains a polyamide resin in addition to the cellulose resin (A) and the plasticizer. Moreover, from the viewpoint of blocking resistance and heat resistance, it is preferable that the surface protective layer further contains amide wax.

(Polyamide resin)
As mentioned above, the surface protective layer of the present invention preferably further contains a polyamide resin in addition to the cellulose resin (A) and the plasticizer, from the viewpoint of achieving a gloss value of 25 or more.
Although the polyamide resin is not particularly limited, it is preferably a thermoplastic polyamide soluble in an organic solvent, and a polycondensate of a polybasic acid and a polyvalent amine is preferably used.
Among these, polyamide resins containing a reaction product of an acid component containing a polymerized fatty acid and/or a dimer acid and an aliphatic and/or aromatic polyamine are preferred, and those containing a portion of primary and secondary monoamines are more preferred.

Examples of polybasic acids used as raw materials for polyamide resin include adipic acid, sebacic acid, azelaic acid, phthalic anhydride, isophthalic acid, suberic acid, glutaric acid, fumaric acid, pimelic acid, oxalic acid, malonic acid, Examples include succinic acid, maleic acid, terephthalic acid, 1,4-cyclohexyldicarboxylic acid, trimellitic acid, dimer acid, hydrogenated dimer acid, and polymerized fatty acids. Among them, dimer acids and polymerized fatty acids are preferably used.
The polyamide resin preferably has a structure derived from a polymerized fatty acid or a (hydrogenated) dimer acid, and it is preferable that the polyamide resin contains 50% by mass or more of a structure derived from a dimer acid and a polymerized fatty acid.
Here, the polymerized fatty acid is obtained by a cyclization reaction of unsaturated fatty acids, and includes monobasic fatty acids, dimerized fatty acids, trimerized fatty acids, and the like. When using polymerized fatty acids, monobasic fatty acids containing unsaturated fatty acids or those obtained by ester polymerization thereof are preferable, and those obtained by polymerization of unsaturated fatty acids having 16 to 22 carbon atoms or their esters are preferable. . One type of polymerized fatty acid may be used alone, or two or more types may be used in combination in any ratio.
The fatty acids constituting the dimer acid or polymerized fatty acid are preferably derived from natural oils such as soybean oil, palm oil, and rice bran oil, and more preferably are those derived from oleic acid and linoleic acid.
A monocarboxylic acid can also be used in combination with the polybasic acid. Examples of monocarboxylic acids used in combination include acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid, and cyclohexanecarboxylic acid.

Examples of polyvalent amines include polyamines and primary or secondary monoamines.
The above polyamines include aliphatic diamines such as ethylene diamine, propylene diamine, hexamethylene diamine, and methylaminopropylamine; aliphatic polyamines such as diethylene triamine and triethylene tetramine; alicyclic polyamines such as cyclohexylene diamine and isophorone diamine; Examples include aromatic aliphatic polyamines such as amines; aromatic polyamines such as phenylenediamine and diaminodiphenylmethane.
Examples of primary and secondary monoamines include n-butylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, and dipropanolamine.
From the viewpoints of adhesiveness, blocking resistance, oil resistance, and heat resistance, the polyamide resin preferably has a hydroxyl group in the molecule, and it is preferable to use an alkanolamine as the primary or secondary monoamine component.

As commercially available polyamide resins, for example, Vegechem Green series (manufactured by Tsukino Shokuhin Kogyo Co., Ltd.), Newmide series (manufactured by Harima Kasei Co., Ltd.), etc. can be used.

The polyamide resin preferably has a softening point of 80 to 140°C, more preferably 90 to 120°C. When the softening point is 80° C. or higher, the surface tack of the surface protective layer can be easily cut off, and blocking can be suppressed. When the softening point is 140° C. or lower, the surface protective layer becomes flexible and the adhesion between the surface protective layer and the printed layer is improved.
The weight average molecular weight of the polyamide resin is preferably in the range of 2,000 to 70,000, more preferably 5,000 to 30,000, from the viewpoint of solubility of the polyamide resin. When the weight average molecular weight is 2,000 or more, the surface protective layer becomes tough and heat resistance improves. When the weight average molecular weight is 50,000 or less, the viscosity of the overcoat agent can be lowered and storage stability becomes good.
Note that the softening point can be measured in accordance with JIS K 2207 (ring and ball method).

In the surface protective layer, the mass ratio of cellulose resin (A) to polyamide resin is preferably 99:1 to 15:85, more preferably 50:50 to 15:85, even more preferably 30:70 to 15: It is 85. Within the above range, the surface protective layer has a good balance of hardness, toughness, and surface smoothness, and has excellent blocking resistance, heat resistance, and gloss.

(Other resins)
The overcoat agent may contain other resins than the cellulose resin (A) and the polyamide resin, as long as the effects of the present invention are not impaired. Examples of other resins include polylactic acid resin, urethane resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, rosin resin, vinyl acetate resin, and ethylene-vinyl acetate copolymer resin. Coalescence resin, vinyl acetate resin, acrylic resin, urethane-acrylic resin, styrene resin, styrene-acrylic acid resin, styrene-allyl alcohol resin, styrene-maleic acid resin, maleic anhydride resin, maleic acid resin, rosin-modified maleic acid resin , cycloolefin resin, dammar resin, polyester resin, alkyd resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, polyacetal resin, silicone resin, and modified resins thereof.

(Organic solvent)
The overcoat agent may contain an organic solvent. Examples of organic solvents include hydrocarbons such as methylcyclohexane and ethylcyclohexane; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone; esters such as ethyl acetate, n-propyl acetate, and butyl acetate; Alcohol-based non-aromatic organic solvents such as alcohol, ethanol, propanol, isopropanol (IPA), and butanol can be used. The organic solvent may be appropriately selected in consideration of reducing the amount of solvent remaining in the film after printing, and one type may be used alone or two or more types may be used in combination.

In order to improve halftone dot reproducibility during printing, it is preferable to use a glycol ether solvent. Examples of the glycol ether-based solvent include, but are not particularly limited to, ethylene glycol-based (E.O.-based) ether and propylene glycol-based (P.O.-based) ether.
Among them, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether are preferred, and diethylene glycol monoethyl ether is more preferred. The glycol ether solvent is preferably used in an amount of 5 to 25% by mass in the organic solvent.

(amide wax)
As mentioned above, the overcoat agent and surface protective layer of the present invention preferably further contain amide wax in addition to the cellulose resin (A) and the plasticizer from the viewpoint of blocking resistance and heat resistance.
The amide wax is a fatty acid amide, and preferably has a fatty acid residue and an amide group. It is thought that the fatty acid amide is oriented on the surface of the surface protective layer after printing, exhibits slipperiness, and improves blocking resistance. Note that this explanation is based on technical considerations and does not limit the invention in any way.

Preferred fatty acid amides include, for example, monoamides, substituted amides, bisamides, methylolamides, and esteramides, and preferably at least one selected from the group consisting of monoamides, substituted amides, and bisamides.

The melting point of the fatty acid amide is preferably 50°C to 150°C.
Examples of monoamides having a melting point of 50°C to 150°C include lauric acid amide (melting point 87°C), palmitic acid amide (melting point 100°C), stearic acid amide (melting point 101°C), behenic acid amide (melting point 110°C), Examples include hydroxystearamide (melting point 107°C), oleic acid amide (melting point 75°C), and erucic acid amide (melting point 81°C).
Examples of substituted amides having a melting point of 50°C to 150°C include N-oleyl palmitic acid amide (melting point 68°C), N-stearyl stearic acid amide (melting point 95°C), and N-stearyl oleic acid amide (melting point 67°C). , N-oleyl stearic acid amide (melting point: 74°C), and N-stearyl erucic acid amide (melting point: 69°C).
Examples of bisamides having a melting point of 50°C to 150°C include methylene bisstearamide (melting point 142°C), ethylene bisstearamide (melting point 145°C), ethylene bishydroxystearamide (melting point 145°C), and ethylene bisstearamide (melting point 145°C). Behenic acid amide (melting point 142°C), hexamethylene bisstearic acid amide (melting point 140°C), hexamethylene bisbehenic acid amide (melting point 142°C), hexamethylene hydroxystearic acid amide (melting point 135°C), ethylene bisoleic acid amide (melting point 119°C), ethylene biserucic acid amide (melting point 120°C), hexamethylenebisoleic acid amide (melting point 110°C), N,N'-distearyladipic acid amide (melting point 141°C), N,N'- Examples include distearyl sebacic acid amide (melting point 136°C), N,N'-dioleyladipic acid amide (melting point 118°C), and N,N'-dioleylsebacic acid amide (melting point 113°C).
Examples of the methylolamide having a melting point of 50°C to 150°C include methylolstearamide (melting point of 110°C).
Examples of esteramides having a melting point of 50°C to 150°C include stearamide ethyl stearate (melting point 82°C).
Among these, those having a molecular weight of 200 to 800 are preferred in order to maintain lamination strength. More preferably it is 250-700.

The fatty acids constituting the fatty acid amide are preferably saturated fatty acids with 12 to 22 carbon atoms and/or unsaturated fatty acids with 16 to 25 carbon atoms, and saturated fatty acids with 16 to 18 carbon atoms and/or unsaturated fatty acids with 18 to 22 carbon atoms. Saturated fatty acids are more preferred. Particularly preferred saturated fatty acids are lauric acid, palmitic acid, stearic acid, behenic acid, and hydroxystearic acid, and particularly preferred unsaturated fatty acids are oleic acid and erucic acid.
Among these, fatty acid amides consisting of at least one fatty acid selected from the group consisting of palmitic acid, stearic acid, behenic acid, hydroxystearic acid, oleic acid, and erucic acid are preferred, and more preferably palmitic acid amide, erucic acid amide, Ethylene bisoleic acid amide is particularly preferred, and ethylene bisoleic acid amide is particularly preferred.

The content of amide wax contained in the surface protective layer is preferably 0.1 to 22.5% by mass, more preferably 0.1 to 15% by mass, and even more preferably 0.1 to 7.5% by mass. It is. When it is within the above range, it is possible to achieve both tack breakage and toughness of the surface protective layer, and the blocking resistance and heat resistance are improved.

(Additive)
The surface protective layer may contain optional components such as additives within a range that does not impair the effects of the present invention.

《Hydrocarbon wax particles》
Preferably, the overcoat agent and the surface protective layer contain hydrocarbon wax particles. Including hydrocarbon wax particles improves the abrasion resistance of the surface protective layer.
The hydrocarbon wax particles are preferably hydrocarbon wax particles having a hardness (penetration) of 0.5 to 12. Examples of hydrocarbon wax particles include polyethylene wax, Fischer-Tropsch wax, paraffin wax, microstalline wax, and polypropylene wax. Among them, hydrocarbon waxes including polyethylene wax are preferred.
In the overcoat agent, the average particle diameter of the hydrocarbon wax particles is preferably 0.3 to 10 μm, more preferably 0.8 to 7 μm. The content of the hydrocarbon wax particles in the surface protective layer is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass.

《Chelate crosslinking agent》
It is preferable that the overcoat agent and the surface protective layer contain a chelate crosslinking agent. Examples of the chelate crosslinking agent include titanium chelate and zirconium chelate. Examples of titanium chelates include titanium alkoxides such as tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate, and tetrastearyl titanate, triethanolamine titanate, titanium acetylacetetonate, and titanium. Tetraacetylacetonate, tetraisopropoxytitanium, titanium ethyl acetoacetate, titanium lactate, octylene glycol titanate, titanium n-butyl phosphate, propanediox titanium bis(ethyl acetylacetate), and the like can be mentioned. Examples of the zirconium chelate include zirconium propionate, zirconium acetylacetate, and the like. Among these, chelate crosslinking agents that do not generate acetylacetone after the crosslinking reaction are preferred from an environmental standpoint.

The content of the chelate crosslinking agent in the surface protective layer is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass. When the content is 0.1% by mass or more, heat resistance, oil resistance, and vinyl chloride blocking resistance are improved, and when the content is 5.0% by mass or less, the overcoat agent has excellent storage stability. The use of these chelate crosslinking agents has the effect of improving the abrasion resistance of the formed film.

<Print layer>
The printing layer in the present invention is a layer containing a pigment and a binder resin, and is arranged on the surface of the paper base material opposite to the surface provided with the heat seal layer. The printing layer is formed using printing ink, and the printing method can be appropriately selected from known printing methods such as gravure printing and flexo printing, with gravure printing being preferred. The thickness of the printed layer is preferably 0.1 to 10 μm, more preferably 0.3 to 6 μm, and particularly preferably 0.5 to 3 μm.
In this specification, the term "printed layer" includes not only a single printed layer but also a layer in which a plurality of printed layers are laminated, and printed layers having different hues can be arbitrarily combined.

[Printing ink]
The printing ink contains a pigment and a binder resin, and may further contain an organic solvent and optional additives. From the viewpoint of pigment dispersibility and workability, the printing ink preferably has a viscosity of 50 to 1,000 mPa·s at 25°C.

(pigment)
Examples of pigments include organic pigments, inorganic pigments, and extender pigments.
《Organic pigment》
Examples of organic pigments include organic compounds and organometallic complexes, such as soluble azo, insoluble azo, azo, phthalocyanine, halogenated phthalocyanine, anthraquinone, anthurone, dianthraquinonyl, and anthraquinone. Pyrimidine series, perylene series, perinone series, quinacridone series, thioindigo series, dioxazine series, isoindolinone series, quinophthalone series, azomethine azo series, flavanthrone series, diketopyrrolopyrrole series, isoindoline series, indanthrone series, carbon black One example is the system.
Also, for example, Carmine 6B, Lake Red C, Permanent Red 2B, Disazo Yellow, Pyrazolone Orange, Carmine FB, Chromophthal Yellow, Chromophthal Red, Phthalocyanine Blue, Phthalocyanine Green, Dioxazine Violet, Quinacridone Magenta, Quinacridone Red, Indance. Examples include lon blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, and daylight fluorescent pigments.

The hue of the organic pigment is preferably at least one selected from the group consisting of black pigment, indigo pigment, green pigment, red pigment, purple pigment, yellow pigment, orange pigment, and brown pigment. Furthermore, at least one selected from the group consisting of black pigments, indigo pigments, red pigments, and yellow pigments is more preferred.

Specific examples of organic pigments are listed in C.I. of Color Index International (abbreviated as C.I.). I. Indicate by number.
Preferably C. I. Pigment Red 57:1, C.I. I. Pigment Red 48:1, C.I. I. Pigment Red 48:2, C. I. Pigment Red 48:3, C.I. I. Pigment Red 146, C. I. Pigment Red 242, C. I. Pigment Yellow 83, C. I. Pigment Yellow 14, C. I. Pigment Orange 38, C. I. Pigment Orange 13, C. I. Pigment Yellow 180, C. I. Pigment Yellow 139, C. I. Pigment Red 185, C. I. Pigment Red 122, C. I. Pigment Red 178, C. I. Pigment Red 149, C. I. Pigment Red 144, C. I. Pigment Red 166, C. I. Pigment Violet 23, C. I. Pigment Violet 37, C. I. Pigment Blue 15, C. I. Pigment Blue 15:1, C. I. Pigment Blue 15:2, C. I. Pigment Blue 15:3, C. I. Pigment Blue 15:4, C. I. Pigment Blue 15:6, C. I. Pigment Green 7, C. I. Pigment Orange 34, C. I. Pigment Orange 64, C. I. Pigment Black 7, and it is preferable to use one kind or two or more kinds.

《Inorganic pigment》
Examples of inorganic pigments include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, aluminum particles, mica, bronze powder, chrome vermilion, chrome yellow, cadmium red, and titanium oxide. , ultramarine, navy blue, red iron oxide, yellow iron oxide, iron black, titanium oxide, and zinc oxide.Aluminum can be of leafing type or non-leafing type, but non-leafing type is preferable.

The inorganic pigment preferably contains titanium oxide. Any titanium oxide having an anatase type, rutile type, or brookite type crystal structure may be used, and two or more types may be used in combination. Among them, it is preferable to use rutile-type titanium oxide because of its excellent pigment dispersibility.
In addition, it is preferable that the titanium oxide be surface-treated so that printability in gravure printing is improved. Particularly preferred are those whose surface has been treated with at least one metal selected from Si, Al, Zn, Zr, and their oxides.

The oil absorption of titanium oxide measured in accordance with JIS K5101 is preferably 14 to 35 ml/100 g, more preferably 17 to 32 ml/100 g. Further, the titanium oxide preferably has an average particle size (median particle size) of 0.2 to 0.3 μm as measured by a transmission electron microscope.

《Extender pigment》
As extender pigments, silica, barium sulfate, kaolin, clay, calcium carbonate, magnesium carbonate, etc. are preferably used.

(binder resin)
The binder resin is not particularly limited and can be appropriately selected from known resins used in printing inks. Examples of such binder resins include polylactic acid resin, urethane resin, cellulose resin, polyamide resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, castor oil resin, Rosin resin, vinyl acetate resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, acrylic resin, urethane-acrylic resin, styrene resin, styrene-acrylic acid resin, styrene-allyl alcohol copolymer resin, styrene-maleic acid Copolymer resin, maleic anhydride resin, maleic acid resin, rosin-modified maleic acid resin, cycloolefin resin, dammar resin, polyester resin, alkyd resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, chlorinated rubber, Examples include butyral, polyacetal resin, silicone resin, and modified resins thereof, and one type can be used alone or two or more types can be used in combination.
It is preferable that the printing layer contains cellulose resin (B) as a binder resin.

(Cellulose resin (B))
As the cellulose resin (B), cellulose ester resin is suitable. Cellulose ester resin is a resin obtained by esterifying cellulose derived from non-edible plants such as wood fibers and cotton, and examples include cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and nitrocellulose. The cellulose ester resin is preferably nitrocellulose from the viewpoint of heat resistance.
As for the cellulose resin (B) and its preferred embodiments, the description in the above section (Cellulose resin (A)) can be cited.

(Resin (C))
The printing layer further contains, as a binder resin, at least one resin (C) selected from the group consisting of polyamide resin, urethane resin, styrene-maleic acid copolymer resin, styrene-allyl alcohol copolymer resin, and acrylic resin. It is preferable to contain.
Among these, the resin (C) preferably contains at least one selected from the group consisting of polyamide resins, urethane resins, and styrene-maleic acid resins, and more preferably contains urethane resins.

《Urethane resin》
The urethane resin preferably has a weight average molecular weight of 10,000 to 100,000, more preferably 20,000 to 80,000. The glass transition temperature is preferably 0°C or lower, more preferably -60 to 0°C, even more preferably -40 to -5°C. When it is within the above range, both the toughness and flexibility of the printed layer can be achieved, resulting in good heat resistance and good adhesion between the printed layer and the base material.
Further, the urethane resin preferably has an amine value and/or a hydroxyl value, and the amine value is preferably 10 mgKOH/g or less, and 5 mgKOH/g or less in view of browning when mixed with the cellulose resin (B). /g or less is more preferable, and 3 mgKOH/g or less is particularly preferable. The hydroxyl value is preferably 0.5 to 30 mgKOH/g, more preferably 1 to 20 mgKOH/g. Within the above range, it is possible to achieve both adhesion to the substrate and affinity for alcohol solvents, and the adhesion between the printing layer and the substrate and alcohol bleed resistance are improved.

The above amine value is the number of mg of potassium hydroxide equivalent to the equivalent of hydrochloric acid required to neutralize the amino groups contained in 1 g of resin. The method for measuring the amine value is as follows.
[Method for measuring amine value]
Accurately weigh 5 to 10 g of the sample (solid mass of sample S, g). Add 25 mL of toluene and 25 mL of n-butanol to the accurately weighed sample and dissolve thoroughly. Add 30 mL of methanol to this, and perform potentiometric titration with a 0.1 mol/L hydrochloric acid aqueous solution (potency: f). Using the titration amount (AmL) at this time, the amine value can be determined by the following (Formula 1).

(Formula 1)
Amine value = (A x f x 0.1 x 56.108)/S [mgKOH/g]

The above hydroxyl value is the value obtained by converting the amount of hydroxyl groups in 1 g of resin into mg of potassium hydroxide, which is calculated by acetylating the hydroxyl groups in the resin with an excess of acetylation reagent and back titrating the remaining acid with an alkali. In accordance with JIS K0070.

The urethane resin preferably contains structural units derived from polyether polyol and/or polyester polyol, and the total content thereof is preferably 10 to 50% by mass based on 100% by mass of the urethane resin solid content, and more preferably It is preferably 10 to 60% by weight, more preferably 5 to 80% by weight. When it is within the above range, the printed layer can have both toughness and flexibility, resulting in good heat resistance and good adhesion between the printed layer and the base material.
The urethane resin is not limited, but for example, a urethane resin obtained by reacting a polyamine as a chain extender with a urethane prepolymer having an isocyanate group at the end obtained by reacting a polyol and a polyisocyanate. Can be mentioned.

As the polyol, for example, various known polyester polyols, polyether polyols, etc. can be used, and one type or two or more types of each may be used in combination.
Examples of the polyester polyols include polyester polyols obtained by dehydration condensation or polymerization of saturated or unsaturated low-molecular-weight polyols and polyhydric carboxylic acids or their anhydrides; cyclic ester compounds such as polycaprolactone, polyvalerolactone, Examples include polyester polyols obtained by ring-opening polymerization of lactones such as poly(β-methyl-γ-valerolactone).
Examples of the saturated or unsaturated low-molecular polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2methyl-1,3propanediol, 2ethyl-2butyl-1,3propane. Diol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4- Examples include butylene diol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, and pentaesthritol. . Examples of the polyhydric carboxylic acids include adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, and sebacic acid. Acids include trimellitic acid and pyromellitic acid.
Examples of polyether polyols include polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, and tetrahydrofuran.
Both the polyester polyol and the polyether polyol preferably have a branched structure.

Examples of the polyisocyanate include various known aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc. that are commonly used in the production of urethane resins. These may form a trimer to form an isocyanurate ring structure.
Examples of the aromatic diisocyanate include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzylisocyanate, dialkyldiphenylmethane diisocyanate, Examples include tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and tolylene diisocyanate.
Examples of the aliphatic diisocyanate include butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.
Examples of the alicyclic diisocyanate include cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, Examples include norbornane diisocyanate, m-tetramethylxylylene diisocyanate, hydrogenated 4,4-diphenylmethane diisocyanate, and dimer diisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group.
Among these, at least one selected from the group consisting of tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, bis(isocyanatomethyl)cyclohexane, hexamethylene diisocyanate, and a trimer of hexamethylene diisocyanate is preferred. These polyisocyanates can be used alone or in combination of two or more.

Examples of the polyamine as a chain extender include ethylene diamine, propylene diamine, hexamethylene diamine, isophorone diamine, dicyclohexylmethane-4,4'-diamine, and the like. In addition, as polyamines, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxyethylpropylenediamine, Polyamines having a hydroxyl group in the molecule, such as -hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine, may also be used. These chain extenders can be used alone or in combination of two or more, and isophorone diamine is particularly preferred.

《Polyamide resin》
Although the polyamide resin is not particularly limited, it is preferably a thermoplastic polyamide soluble in an organic solvent, and a polycondensate of a polybasic acid and a polyvalent amine is preferably used.
Among these, polyamide resins containing a reaction product of an acid component containing a polymerized fatty acid and/or a dimer acid and an aliphatic and/or aromatic polyamine are preferred, and those containing a portion of primary and secondary monoamines are more preferred.
As for the polyamide resin and its preferred embodiments, the description in the above section (Polyamide resin) can be cited.

《Styrene-maleic acid copolymer resin》
The styrene-maleic acid copolymer resin can be obtained, for example, by radical copolymerization of a styrene monomer and a maleic acid monomer. The solid content mass ratio of styrene monomer and maleic acid monomer is preferably 1:9 to 6:4, more preferably 2:8 to 5:5.

The styrene-maleic acid copolymer resin preferably has an acid value of 150 to 300 mgKOH/g, more preferably 215 to 270 mgKOH/g. When the acid value of the styrene-maleic acid copolymer is 150 mgKOH/g or more, halftone dot reproducibility tends to improve, and when it is 300 mgKOH/g or less, the solubility in solvents increases and the storage stability of the printing ink increases. Excellent in sex. Note that the acid value is the number of mg of potassium hydroxide required to neutralize the acidic groups contained in 1 g of resin solid content, and is based on JIS K 0070.

The glass transition temperature of the styrene-maleic acid copolymer resin is preferably 60 to 125°C, more preferably 70 to 105°C. When the glass transition temperature of the styrene-maleic acid copolymer is 60° C. or higher, the printed layer becomes tougher and thus the heat resistance tends to improve. When the glass transition temperature is 125° C. or less, the solubility in solvents is high and the printing ink has excellent storage stability. The weight average molecular weight is preferably 6,000 to 16,000, more preferably 10,000 to 15,000. In the case of the above range, both toughness and flexibility of the printed layer can be achieved, and heat resistance and adhesion between the printed layer and the base material are improved.

Commercially available styrene-maleic acid copolymer resins include, for example, the XIRAN series (manufactured by Kawasaki Kagaku Co., Ltd.) and the Alastair series (manufactured by Arakawa Chemical Co., Ltd.).

《Styrene-allyl alcohol copolymer resin》
The styrene-allylic alcohol copolymer resin can be obtained, for example, by radical copolymerization of a styrene monomer and an allyl alcohol monomer. The solid content mass ratio of styrene monomer and allyl alcohol monomer is preferably styrene monomer/allyl alcohol monomer = 1/9 to 6/4, more preferably 2/8 to 5/5.

The styrene-allyl alcohol copolymer resin preferably has a hydroxyl value of 150 to 300 mgKOH/g, more preferably 180 to 250 mgKOH/g. When the hydroxyl value of the styrene-allylic alcohol copolymer is 100 mgKOH/g or more, the halftone reproducibility tends to improve, and when it is 50 mgKOH/g or less, the solubility in solvents increases and the storage stability of the printing ink increases. They tend to be excellent.

The glass transition temperature of the styrene-allylic alcohol copolymer resin is preferably 40 to 100°C, more preferably 50 to 80°C. When the glass transition temperature of the styrene-allylic alcohol copolymer is 40° C. or higher, the printed layer tends to be tough and have improved heat resistance and abrasion resistance. When the glass transition temperature is 100° C. or less, the solubility in solvents becomes high, and the printing ink tends to have excellent storage stability. The weight average molecular weight of the styrene-allyl alcohol copolymer is preferably from 1,000 to 5,000, more preferably from 2,000 to 4,000. In the case of the above range, both toughness and flexibility of the printed layer can be achieved, and heat resistance, abrasion resistance, and adhesion between the printed layer and the base material are improved. The acid value is preferably 50 to 300 mgKOH/g, more preferably 100 to 200 mgKOH/g.

Commercially available styrene-allyl alcohol resins include, for example, the SAA series (manufactured by Iondellbasell).

"acrylic resin"
Acrylic resins are obtained by polymerizing monomers having unsaturated double bonds, including (meth)acrylic monomers, in a solvent using a polymerization initiator. The glass transition temperature of the acrylic resin is preferably 40 to 110°C, more preferably 60 to 90°C. When the glass transition temperature of the acrylic resin is 40°C or higher, the toughness of the printed layer tends to be high and the heat resistance tends to improve. When the glass transition temperature is 110° C. or lower, the solubility in solvents becomes high, and the printing ink tends to have excellent storage stability. Further, the weight average molecular weight of the acrylic resin is preferably 5,000 to 100,000, more preferably 8,000 to 40,000. In the case of the above range, the printed layer can have both toughness and flexibility, and the heat resistance and the adhesion between the printed layer and the base material are improved.

The glass transition temperature of the acrylic resin and the vinyl chloride-vinyl acetate copolymer resin was measured using a differential scanning calorimeter (DSC measurement device, "DSC-60A" manufactured by Shimadzu Corporation) as described in the section (Nitrocellulose resin (A)) above. ), but it can be estimated using the FOX formula below.
<FOX style>
1/Tg=W1/Tg1+W2/Tg2+...+Wi/Tgi+...+Wn/Tgn
[In the above FOX formula, the glass transition temperature of the homopolymer of each monomer constituting the polymer consisting of n types of monomers is Tgi (K), the mass fraction of each monomer is Wi, and (W1+W2+... +Wi+...Wn=1). ]

Examples of the monomer having an unsaturated double bond containing the (meth)acrylic monomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n- At least one alkyl ester compound of (meth)acrylic acid such as hexyl (meth)acrylate, n-octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate; N-methylol (meth)acrylamide, etc. (Meth)acrylic acid amide derivatives containing N-substituted methylol groups; dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dipropylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl Aminoalkyl esters of (meth)acrylic acid such as (meth)acrylate and dipropylaminopropyl (meth)acrylate; Mono- or diesters of (meth)acrylic acid of glycols such as diethylene glycol and dipropylene glycol; Styrene, α- Styrene derivatives such as methylstyrene; hydroxyalkyl ester compounds of (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-hydroxypropyl (meth)acrylate; acrylic acid, methacrylic Vinyl compounds having an acid group such as acid, maleic acid, itaconic acid, etc. can be mentioned.
From the viewpoint of adhesion to the paper base material and surface protective layer and heat resistance, the acrylic resin preferably has a carboxyl group and/or a hydroxyl group. When the acrylic resin has a hydroxyl group, the monomer constituting the acrylic resin (meth) ) Those containing a hydroxyalkyl ester compound of acrylic acid are preferred.

Examples of commercially available acrylic resins include the DIANAL series (manufactured by Mitsubishi Rayon Co., Ltd.) and the ACRYDIC series (manufactured by DIC Co., Ltd.).

The mass ratio of cellulose resin (B) to resin (C) in the printing layer is preferably 99:1 to 30:70, more preferably 99:1 to 50:50, and still more preferably 99:1 to 80. :20. When it is within the above range, the printed layer can have both hardness and toughness, and the puncture resistance, blocking resistance, and heat resistance are improved.

The content of the binder resin contained in the printing layer is preferably 20 to 80% by mass, more preferably 40 to 60% by mass. When it is within the above range, the printed layer can have both hardness and flexibility, and the puncture resistance, blocking resistance, and adhesion between the printed layer and the paper base material are improved.

(Organic solvent)
The printing ink may contain an organic solvent. Examples of organic solvents include hydrocarbons such as methylcyclohexane and ethylcyclohexane; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone; esters such as ethyl acetate, n-propyl acetate, and butyl acetate; Alcohol-based non-aromatic organic solvents such as alcohol, ethanol, propanol, isopropanol (IPA), and butanol can be used. The organic solvent may be appropriately selected in consideration of reducing the amount of solvent remaining in the film after printing, and one type may be used alone or two or more types may be used in combination.
As for the organic solvent and its preferred embodiment, the description in the above-mentioned [Overcoating Agent] (Organic Solvent) section can be referred to.

(Other ingredients)
The printing ink and the printing layer may further contain pigment dispersants, isocyanate curing agents, chelate crosslinking agents, hydrocarbon wax particles, matting agents, vapor phase silica, wet silica, organic Additives such as finely powdered silica such as treated silica and alumina-treated silica, polyethylene wax, fatty acid amide wax, antifoaming agents, leveling agents, plasticizers, infrared absorbers, ultraviolet absorbers, and flame retardants can be used.

《Pigment dispersant》
As the pigment dispersant, anionic, nonionic, cationic, amphoteric, and other surfactants can be used.

《Isocyanate curing agent》
As the isocyanate curing agent, polyisocyanates and modified compounds thereof can be used. Specifically, biuret, isocyanurate, and adduct polyisocyanates are preferred, and diisocyanates are preferred as polyisocyanates; aromatic diisocyanates such as tolylene diisocyanate; 1,4-cyclohexane diisocyanate, isophorone diisocyanate, etc. Alicyclic diisocyanates; aliphatic diisocyanates such as hexamethylene diisocyanate; and araliphatic diisocyanates such as α, α, α', α'-tetramethylxylylene diisocyanate are preferably used.
Commercially available isocyanate curing agents include, for example, 24A-100, 22A-75, TPA-100, TSA-100, TSS-100, TAE-100, TKA-100, P301-75E, E402-808, E405- 70B, AE700-100, D101, D201, A101H (Asahi Kasei), My Tech Y260A (Mitsubishi Chemical), Coronate HX, Coronate Coronate HL, Coronate Coronate L (manufactured by Japan) Module N75MPA / X (manufactured by Bayer). Among these, isophorone diisocyanate and adducts and/or isocyanurates of isophorone diisocyanate are preferred.

《Chelate crosslinking agent》
Preferably, the printing ink and printing layer contain a chelate crosslinking agent. As for the chelate crosslinking agent and its preferred embodiment, the description in the above-mentioned [Overcoating agent] <<Chelate crosslinking agent>> section can be cited.
The content of the chelate crosslinking agent in the printed layer is preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight. When the content is 0.1% by mass or more, heat resistance, oil resistance, and vinyl chloride blocking resistance are improved, and when the content is 5.0% by mass or less, the printing ink has excellent storage stability. The use of these chelate crosslinking agents has the effect of improving adhesion to surface-coated paper substrates.

《Hydrocarbon wax particles》
Preferably, the printing ink and the printing layer contain hydrocarbon wax particles. The inclusion of hydrocarbon wax particles improves the adhesion to the paper substrate and the abrasion resistance of the printed layer. As for the hydrocarbon wax particles and their preferred embodiments, the description in the above-mentioned [Overcoat Agent] <<Hydrocarbon Wax Particles>> section can be cited.
In the overcoat agent, the average particle diameter of the hydrocarbon wax particles is preferably 0.3 to 10 μm, more preferably 0.8 to 7 μm. The content of the hydrocarbon wax particles in the surface protective layer is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass.

《Plasticizer》
It is preferable that the printing ink and the printing layer contain a plasticizer. The plasticizer, when added in a small amount, has the role of accelerating the volatility of the organic solvent, imparting flexibility to the printing layer, and improving adhesion to the paper base material. As for the plasticizer and its preferred embodiment, the description in the above-mentioned [Overcoat agent] (Plasticizer) section can be referred to.
The printing layer in the present invention preferably contains at least one plasticizer selected from the group consisting of castor oil, glycol ether, aliphatic dibasic acid ester, and tributyl acetyl citrate, and castor oil is more preferable.
The content of plasticizer in the printing layer is preferably 0.1 to 15% by weight, more preferably 5 to 15% by weight, and still more preferably 11 to 15% by weight. When it is within the above range, both hardness and toughness of the printed layer can be achieved, and blocking resistance and heat resistance are improved.

<Heat seal layer>
The heat-sealing layer in the present invention includes a polyethylene resin and is located on the paper substrate opposite the side provided with the printing layer. Examples of the polyethylene resin include low-density polyethylene resin, linear low-density polyethylene resin, medium-density polyethylene resin, and high-density polyethylene resin, and the melting point of the polyethylene resin is preferably 90 to 150°C.
The heat seal layer only needs to have a polyethylene resin as its main component, and may contain components other than polyethylene resin. The heat seal layer preferably contains polyethylene resin in an amount of 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.
The heat-sealing layer is formed by, for example, extruding a polyethylene resin heat-melted at 300 to 400°C into a film using a slit-shaped device called a T-die and coating (laminating) it on a paper base material. can do.
The thickness of the heat seal layer is preferably 5 to 100 μm, more preferably 15 to 50 μm.

<Paper base material>
The paper base material is not particularly limited, and any known paper base material can be used. Such paper base materials include, for example, medium-quality paper, high-quality paper, newsprint, Yupo paper, various types of coated paper, lined paper, impregnated paper, cardboard, art paper, cast paper, kraft paper, coated board, and ivory paper. Examples include paper, card paper, cup base paper, cast paper, light-shielding paper, and surface-treated paper base materials thereof.
Further, the paper base material may be a vapor-deposited paper on which a metal oxide such as silica or alumina, or a metal such as aluminum (also referred to as an inorganic compound) is vapor-deposited. The vapor-deposited paper may have an anchor layer between the paper base material and the vapor-deposited layer in order to uniformly form the vapor-deposited layer on the paper base material, and the vapor-deposited layer may be coated with polyvinyl alcohol or the like. may have been applied.
The thickness of the paper base material is preferably 50 to 150 g/m ² , more preferably 60 to 120 g/m ² , and still more preferably 60 to 90 g/m ² .

<Barrier layer>
It is preferable that the packaging material of the present invention further includes a barrier layer. The barrier layer is preferably disposed between the paper base layer and the printing layer, and preferably contains an inorganic compound such as aluminum, alumina, or silica. The purity of the inorganic compound is preferably 99% or more, more preferably 99.9% or more.
The method for forming the barrier layer is not particularly limited, and the inorganic compound layer can be formed on the paper base material by a known method such as a vacuum evaporation method or a sputtering method. Further, by using the above-mentioned vapor-deposited paper, a barrier layer can also be provided on the paper base material.
The vacuum evaporation method is performed under conditions of 1200 to 1500° C. and about 10 ⁻¹ to 10 ⁻² Pa using high-frequency induction heating, direct current heating, electron beam heating, or the like. The surface of the object to be deposited can be subjected to adhesion improvement treatment such as corona discharge treatment before vacuum deposition. The thickness of the inorganic compound film formed by vacuum deposition is preferably 10 to 300 nm from the viewpoints of barrier properties, light shielding properties, and economic efficiency.
The sputtering method is carried out by introducing an inert gas such as Ar and applying a voltage under conditions of approximately 10 ⁻¹ to 10 ⁻² Pa. The thickness of the inorganic compound film to be formed is preferably 10 to 300 nm from the viewpoints of barrier properties, light shielding properties, and economic efficiency.

<Manufacturing method of packaging material>
The packaging material of the present invention includes a step of printing printing ink on one side of a paper base material to form a printing layer, and printing an overcoat agent containing a cellulose resin (A) and a plasticizer on the printing layer. and a step of coating the other side of the paper base material with a molten polyethylene resin to form a heat-sealing layer.
In the above steps, the timing of the step of forming the heat-seal layer is not particularly limited, but it is preferable to sequentially form the printing layer, the surface protective layer, and the heat-seal layer.

As a method for forming the printing layer and the surface protective layer, a gravure printing method and a flexographic printing method are suitably used, and the gravure printing method is preferable. Gravure printing enables high-speed printing and significantly improves productivity.

The packaging material of the present invention may have a heat seal layer, a paper base material, a printed layer, and a surface protection layer in this order, and may further have another layer such as the barrier layer described above depending on the required performance. You may do so. Preferred examples of the laminated structure of the packaging material include the following.
Heat sealing layer / Paper base material / Printing layer / Surface protection layer Heat sealing layer / Barrier layer / Paper base material / Printing layer / Surface protection layer Heat sealing layer / Paper base material / Barrier layer / Printing layer / Surface protection layer Heat sealing Layer/paper base material/printing layer/barrier layer/surface protection layer

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples. Note that "parts" and "%" in the present invention represent "parts by mass" and "% by mass" unless otherwise noted. Moreover, "NV." represents the mass % of non-volatile content.

<Preparation of cellulose resin solution>
(Preparation example 1) Preparation of nitrocellulose resin solution NC1 Nitrocellulose nc1 (manufactured by NOBEL, product name NC DHX 5-10, NV. 70% (solvent: isopropyl alcohol), weight average molecular weight: 10,000, solution concentration 25 Viscosity at 0%: 2 seconds) was mixed and dissolved in 33.6 parts of ethyl acetate and 33.6 parts of isopropyl alcohol to obtain a nitrocellulose resin solution (NC1) with a solid content of 30%.

(Preparation Examples 2-4) Preparation of Nitrocellulose Resin Solutions NC2-4 Nitrocellulose resin solutions NC2-5 were obtained in the same manner as in Preparation Example 1, except that the raw materials described below were used. Note that nc4 does not satisfy any of the above-mentioned preferred viscosity ranges (1) to (3).
・(NC2) Nitrocellulose nc2 (manufactured by NOBEL, product name NC DHX 4-6, NV.70% (solvent: isopropyl alcohol), viscosity at 25.0% solution concentration: 1.2 seconds)
・(NC3) Nitrocellulose nc3 (manufactured by NOBEL, product name NC DHX 30-50, NV.70% (solvent: isopropyl alcohol), viscosity at solution concentration 25.0%: 10 seconds)
・(NC4) Nitrocellulose nc4 (manufactured by NOBEL, product name NC DHL 120-170, NV.70% (solvent: isopropyl alcohol), viscosity at solution concentration 12.2%: 20 seconds,)

(Preparation example 3) Preparation of cellulose acetate butyrate resin solution CAB1 Cellulose acetate butyrate (manufactured by EASTMAN CHEMICAL, product name CAB553-0.4, NV. 70% (solvent: isopropyl alcohol), glass transition temperature: 136 ° C. A cellulose acetate butyrate resin solution (CAB1) having a solid content of 30% was obtained by mixing and dissolving 72 parts (weight average molecular weight: 20,000) in 33.6 parts of ethyl acetate and 33.6 parts of isopropyl alcohol.

<Adjustment of resin solution>
(Preparation Example 4) Preparation of polyamide resin solution PA1 30 parts of polyamide resin pa1 (manufactured by Tsukino Shokuhin Kogyo Co., Ltd., product name Vegechem Green 725, NV. 100%, softening point 116°C, weight average molecular weight 8,000), and 70 parts of isopropyl alcohol was charged and dissolved at 50° C. for 2 hours under a nitrogen stream to obtain a polyamide resin solution (PA1) with a solid content of 30%.

(Adjustment Example 5) Adjustment of polyamide resin solutions PA2 and PA3)
Polyamide resin solutions PA2 and PA3 having a solid content of 30% were obtained in the same manner as in Preparation Example 4, except that the raw materials described below were used.
・(PA2) Polyamide resin pa2 (manufactured by Harima Kasei Co., Ltd., product name Newmide 846, NV. 100%, softening point 110°C)
・(PA3) Polyamide resin pa3 (manufactured by Harima Kasei Co., Ltd., product name Newmide 872, NV. 100%, softening point 112°C)

(Preparation Example 6) Preparation of styrene-maleic acid copolymer resin solution SMA1 In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, styrene-maleic acid copolymer resin (raw crude oil Company, product name: XIRAN2625P), NV. 100%, glass transition temperature 110°C, weight average molecular weight 9,000, acid value 270mgKOH/g), 33.3 parts of ethyl acetate and 33.3 parts of isopropyl alcohol were charged, and the mixture was heated at 50°C under a nitrogen stream. After dissolving for a period of time, a styrene-maleic acid copolymer resin solution (SMA1) with a solid content of 30% was obtained.

(Preparation Example 7) Preparation of styrene-allyl alcohol resin solution SA1 Styrene-allyl alcohol resin (manufactured by Iyondellbasell, product name SAA-100, NV. 100%, hydroxyl value: 205 mgKOH/g, weight average molecular weight 3,100) 30 and 70 parts of ethyl acetate were charged therein and dissolved at 50° C. for 2 hours under a nitrogen stream to obtain a styrene-allylic alcohol copolymer resin solution (SA1) with a solid content of 30%.

(Preparation Example 8) Preparation of acrylic resin solution AC1 30 parts of acrylic resin (manufactured by Gifu Cerac Co., Ltd., product name TSA-28, NV. 100%, weight average molecular weight 10,000, acid value 195 mgKOH/g), 70 parts of ethyl acetate was charged and dissolved at 50° C. for 2 hours under a nitrogen stream to obtain an acrylic resin solution (AC1) with a solid content of 30%.

(Preparation Example 9) Preparation of vinyl chloride-vinyl acetate copolymer resin solution PVC1 Vinyl chloride-vinyl acetate copolymer resin (manufactured by Nissin Chemical Industry Co., Ltd., product name Solvine TA5R, NV. 100%, glass transition temperature 78°C, weight 30 parts (average molecular weight: 61,000) and 70 parts of ethyl acetate were charged and dissolved at 50°C for 2 hours under a nitrogen stream to obtain a vinyl chloride-vinyl acetate copolymer resin solution (PVC1) with a solid content of 30%.

(Preparation Example 10) Preparation of urethane resin solution PU1 Poly(1,2-propylene glycol) having a number average molecular weight of 2,000 ( 257.86 parts of hydroxyl value 56.1 mgKOH/g), 18.01 parts of isophorone diisocyanate, 20.27 parts of diphenylmethane diisocyanate, 0.03 parts of tin(II) 2-ethylhexanoate, and 200 parts of ethyl acetate were charged, followed by a nitrogen stream. The mixture was reacted at 90° C. for 3 hours to obtain 496.14 parts of a solution of terminal isocyanate prepolymer. Next, a mixture of 3.86 parts of isophoronediamine, 280 parts of isopropyl alcohol, and 220 parts of ethyl acetate was gradually added to the obtained solution of the terminal isocyanate prepolymer at room temperature, and then reacted at 50 ° C. for 1 hour. A urethane resin solution (PU1) was obtained with a solid content of 30%, a weight average molecular weight of 78,000, and an amine value not detected (less than 0.1 mgKOH/g).

(Preparation Example 11) Preparation of chlorinated rubber resin solution CG1 30 parts of chlorinated rubber resin CG1 (manufactured by Sumika Bayer Urethane Co., Ltd., product name: Pergood S20, NV. 100%) and 70 parts of ethyl acetate were charged and heated under a nitrogen stream. The mixture was dissolved at 50° C. for 2 hours to obtain a chlorinated rubber resin solution (CG1) with a solid content of 30%.

<Manufacture of printing ink>
(Production Example 1) Production of printing ink K1 86 parts of Lionol Yellow TT1405G (manufactured by Toyo Color Co., Ltd., NV. 100%), 193 parts of nitrocellulose resin solution NC1, 140 parts of N-propyl acetate, 40 parts of ethyl acetate, isopropyl After stirring and mixing 30 parts of alcohol and dispersing the pigment in a bead mill (using zirconia beads), 193 parts of nitrocellulose resin solution NC1, 93 parts of N-propyl acetate, 18 parts of ethyl acetate, 35 parts of isopropyl alcohol, and polyethylene wax (NV .15%, solvent: ethyl acetate) 40 parts, diethylene glycol monobutyl ether (NV. 100%) 20 parts, castor oil plasticizer (NV. 100%) 16 parts, titanium chelate (NV. 50%, solvent: ethyl acetate) 40 parts were stirred and mixed to obtain printing ink K1.

(Production Examples 2 to 17) Production of Printing Inks K2 to 17 Printing inks K2 to 17 were obtained in the same manner as Production Example 1, except that the raw materials and compounding ratios listed in Table 1 were used.

<Manufacture of overcoat agent>
(Production Example 18) Production of overcoat agent V1 65.5 parts of nitrocellulose resin solution NC1, 5.5 parts of N-propyl acetate, 3 parts of ethyl acetate, 5.5 parts of isopropyl alcohol, 5.4 parts of methylcyclohexane, 0.9 parts of methylpropylene glycol, 0.9 parts of water, 1.85 parts of diethylene glycol monobutyl ether (NV. 100%), and 3 parts of hexamenlene bisoleic acid amide (NV. 100%) were stirred and mixed to form an overcoat. Agent V1 was obtained.

(Production Examples 19 to 31, Comparative Production Examples 1 to 3) Production of Overcoat Agents V2 to 17 In the same manner as Production Example 18 except that the raw materials and compounding ratios listed in Table 2 were used, Overcoat Agents V2 to I got 17.

<Manufacture of packaging materials>
(Example 1) Production of packaging material P1 Printing ink K1 and overcoat agent V4 were diluted with a mixed solvent of ethyl acetate: isopropyl alcohol = 7:3 (mass ratio), and each was diluted with Zahn cup #3 (manufactured by Rigosha) 25 The viscosity was adjusted to 15 seconds at °C.
^{Next ,} aluminum ( (purity of 99.9% or more) was vacuum-deposited to form a barrier layer. A printing layer was formed by printing diluted printing ink K1 on the barrier layer using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm at a printing speed of 50 m/min and an in-line oven of 60° C. After forming, overcoat agent V4 was printed on the printing layer using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm under conditions of a printing speed of 50 m/min and an in-line oven of 60° C. An intermediate laminate p1 having a structure of base material/barrier layer/printed layer/surface protection layer was obtained.
Polyethylene resin (melting point: 120°C) was hot-melt extruded on the opposite side of the printed layer of the base material in the intermediate laminate p1 under conditions of a resin temperature of 330°C, a coating speed of 80 m/min, and a coating thickness of 20 μm. A packaging material P1 having a structure of heat seal layer/paper base material/barrier layer/print layer/surface protection layer was obtained by coating.

(Examples 2 to 34, Comparative Examples 1 to 5) Production of packaging materials P2 to 39 The same procedure was followed as for the production of packaging material P1, except that the printing ink and overcoating agent shown in Table 3 were used. Packaging materials P2 to P39 having the following configurations were respectively produced. The properties of the raw materials used are as follows.
・Polypropylene resin PP1 (manufactured by Mitsubishi Chemical Corporation, product name Novatec PP)

<Evaluation of packaging materials>
The obtained packaging material was evaluated as described below. The results are shown in Table 3.

(Piercing)
The obtained packaging material was cut into 70 mm square pieces, tested under the following test conditions using a method based on JIS 1707, and evaluated according to the following criteria. Note that A, B, and C are within a range that causes no practical problems.
《Piercing test conditions》
Pierce speed: 50mm/min, needle diameter: 1mm,
Needle piercing surface: Overcoat agent surface of second laminate (evaluation criteria)
A. The piercing strength is 12N or more.
B. The puncture strength is 10N or more and less than 12N.
C. The puncture strength is 5N or more and less than 10N.
D. The puncture strength is less than 5N.

(Blocking resistance evaluation)
The obtained packaging material was cut into two pieces of 40 mm square, the heat seal layer surface of one packaging material piece and the surface protection layer surface of the other packaging material piece were completely overlapped, and the temperature was 40 ° C. and the humidity was 80% RH. Pressure bonding was carried out under a load of 100 N/cm ² . After standing still for 24 hours, the two stacked packaging materials were peeled off, and the peeling state of the printed layer was visually observed and evaluated based on the following criteria. Note that A, B, and C are within a range that causes no practical problems.
"Evaluation criteria"
A. No transfer of the printed layer to the heat seal layer surface is observed.
B. The amount of transfer of the printed layer to the surface of the heat seal layer is more than 0 area % and less than 10 area %.
C. The amount of transfer of the printed layer to the surface of the heat seal layer is 10 area % or more and less than 30 area %.
D. The amount of transfer of the printed layer to the surface of the heat seal layer is 30 area % or more.

(glossy)
The 60 degree gloss value of the surface of the surface protective layer of the obtained packaging material was measured using a Micro-TRI-gloss meter manufactured by BYK-Gardner. It was also visually observed and evaluated using the following criteria. The gloss value was measured in accordance with JIS Z8741:1997, 60 degree specular gloss (Gs(60)). Note that A, B, and C are within a range that causes no practical problems.
"Evaluation criteria"
A. The gloss value is 40 or more.
B. The gloss value is 25 or more and less than 40, and there is no matte feeling when visually observed.
C. The gloss value is 25 or more and less than 40, and it has a slightly matte feel when visually observed.
D. A gloss value of less than 25 and a strong matte appearance when visually observed.

(Heat resistance evaluation)
The obtained packaging material was cut into a size of 15 mm x 100 mm, and a glossy aluminum foil (thickness: 15 microns) with a size of 15 mm x 100 mm was layered on the surface protective layer, and heat sealed using the following equipment and conditions. After that, the aluminum foil was peeled off, and the heat resistance was evaluated according to the following criteria based on the peeled state of the printed layer. Note that A, B, and C are within a range that causes no practical problems.
《Heat sealing conditions》
Equipment: Thermal gradient heat sealer [manufactured by Toyo Seiki Co., Ltd.; TYPE, HG-100],
Seal width: 10mm from the bending part, heater temperature: 240℃,
Seal pressure: 2 kg/cm ² , seal time: 1 sec
"Evaluation criteria"
A. No peeling of the printed layer was observed.
B. Less than 20 area percent of the printed layer peeled off.
C. At least 20% by area and less than 50% by area of the printed layer peeled off.
D. More than 50 area% of the printed layer was peeled off.

(Heat sealability evaluation)
The obtained packaging material was cut into a size of 15 mm x 100 mm, bent so that the heat-sealed layer surfaces overlapped, heat-sealed using the following equipment and conditions, and fixed both unsealed ends to a small tensile tester. Heat seal strength was evaluated. Note that A, B, and C are within a range that causes no practical problems.
《Heat sealing conditions》
Equipment: Heat seal tester manufactured by Tester Sangyo Co., Ltd.
Seal width: 10mm from the bending part,
Heater temperature: 160°C, seal pressure: 2kg/cm ² ,
Seal time: 1sec
《Heat seal strength measurement》
Equipment: Intesco small tensile testing machine (model: IM-20), specimen width: 15 mm, peeling mode: 90° peeling, tensile speed: 300 mm/min
"Evaluation criteria"
A. Heat seal strength is 3.5N or more.
B. Heat seal strength is 2.5N or more and less than 3.5N.
C. Heat seal strength is 1.0N or more and less than 2.5N.
D. Heat seal strength is less than 1.0N.

(Water vapor barrier evaluation)
The moisture permeability of the obtained packaging material was measured in accordance with JIS Z0208 and evaluated based on the following criteria. Note that A, B, and C are within a range that causes no practical problems.
"Evaluation criteria"
A. Moisture permeability is less than 5g/m ² ·15h.
B. Moisture permeability is 5 g/m ² ·15 h or more and less than 1000 g/m ² ·15 h.
C. Moisture permeability is 1000 g/m ² ·15 h or more and less than 3000 g/m ² ·15 h.
D. Moisture permeability is 3000g/ ^m2・15h or more.

ADVANTAGE OF THE INVENTION According to the present invention, it was possible to provide a packaging material and a packaging bag that have excellent puncture resistance, blocking resistance, heat resistance, and gloss while maintaining heat-sealing properties and water vapor barrier properties.
In particular, the surface protective layer contains nitrocellulose resin and polyamide resin in the range of 30:70 to 15:85, the printing layer contains nitrocellulose resin and urethane resin in the range of 99:1 to 80:20, and the heat seal layer Example 1 containing a polyethylene resin was excellent in piercing properties, blocking resistance, gloss, heat resistance, heat sealing properties, and water vapor barrier properties.
On the other hand, Comparative Example 1 in which the heat sealing layer contained a polypropylene resin did not meet the standards in heat sealability, and Comparative Example 4 in which the surface protective layer contained urethane resin did not meet the standards in blocking resistance.

Claims (13)

A packaging material comprising a heat seal layer, a paper base material, a printing layer and a surface protection layer in this order,
The heat seal layer includes a polyethylene resin,
A packaging material in which the surface protective layer contains a cellulose resin (A) and a plasticizer. The packaging material according to claim 1, wherein the surface protective layer has a gloss value of 25 or more as measured according to JIS Z 8741. The packaging material according to claim 1 or 2, wherein the cellulose resin (A) has a viscosity measured according to JIS K 6703 that satisfies any of the following (1) to (3).
(1) The viscosity at a solution concentration of 12.2% by mass is 1.5 to 16 seconds.
(2) The viscosity at a solution concentration of 20.0% by mass is 3.0 to 40 seconds.
(3) The viscosity at a solution concentration of 25.0% by mass is 0.1 to 22 seconds. The packaging material according to any one of claims 1 to 3, further comprising a barrier layer. The packaging material according to any one of claims 1 to 4, wherein the cellulose resin (A) contains a nitrocellulose resin. The packaging material according to any one of claims 1 to 5, wherein the printing layer contains cellulose resin (B). Claim 6: The printing layer further contains at least one resin (C) selected from the group consisting of polyamide resin, urethane resin, styrene-maleic acid copolymer resin, styrene-allyl alcohol copolymer resin, and acrylic resin. Packaging materials listed in . The packaging material according to claim 7, wherein the mass ratio of cellulose resin (B) to resin (C) is 99:1 to 30:70. The packaging material according to any one of claims 1 to 8, wherein the surface protective layer further contains a polyamide resin. The packaging material according to claim 9, wherein the mass ratio of cellulose resin (A) and polyamide resin is 99:1 to 15:85. The packaging material according to any one of claims 1 to 10, wherein the surface protective layer further contains amide wax. A packaging bag formed from the packaging material according to any one of claims 1 to 11. A method for producing a packaging material having a heat seal layer, a paper base material, a printing layer and a surface protection layer in this order,
a step of gravure printing a printing ink on one side of a paper base material to form a printing layer;
A step of gravure printing an overcoat agent containing a cellulose resin (A) and a plasticizer onto the printing layer to form a surface protective layer, and a step of coating the other side of the paper base material with a molten polyethylene resin. forming a heat-sealing layer;
A method for manufacturing packaging materials, including: