JP6928766B2 - Manufacturing method for packaging materials, packaging containers and recycled base materials - Google Patents

Description

The present invention relates to a packaging material suitable for recyclability of a plastic base material, a packaging container formed of the packaging material, and a method for producing a recycled base material.

In recent years, packages made from plastic films, plastic bottles and other plastic products have been disposed of and dumped as garbage in the ocean, which has become a problem of environmental pollution. These plastic products are decomposed into submicron-sized fragments (microplastics) in seawater and float in seawater. If the plastic is ingested by marine organisms such as fish, it will be concentrated in the organism and there is a concern that it will affect the health of seabirds and humans who ingest the marine organism as food.

Examples of the plastic products include food packaging packages using a plastic base material. In the package, various plastic base materials such as polyester (PET) base material, nylon (NY) base material, polypropylene (PP) base material and the like are used as the film base material. These plastic base materials are subjected to a printing layer with gravure ink, flexographic ink, and other printing inks, and are further bonded to a heat-melted resin base material via an adhesive or the like to form a laminated body, and then the laminated body is formed. It is cut and heat-sealed to form a package.

In an attempt to reduce the amount of microplastic, (1) the plastic base material is replaced with "paper" made from wood, which is a recyclable resource, and (2) the plastic base material is made of a single material (2). Examples thereof include a method of converting a plastic substrate into a monomaterial and recycling it, and (3) a method of removing impurities and recycling a plastic base material.

The above (1) is promising in terms of safety and recyclability, but there are many aspects inferior in performance to conventional plastic base materials such as gas barrier property, water vapor barrier property, and water resistance.
In (2) above, a technique for covering the weak points of polyolefin with a functional coating agent such as a barrier coating agent is being developed, but the performance is inferior to that of a conventional plastic base material such as retort suitability and light shielding property. , Replacement with polyolefin is not easy. Further, inks, functional coating agents, adhesives, etc. between polyolefin substrates also have a problem of becoming impurities in recycling polyolefins.

As the above (3), an attempt has been made to remove the printed layer on the outer surface of the package, which becomes an impurity in the recycling process, with an alkaline aqueous solution.
For example, Reference 1 discloses a technique in which an undercoat layer made of an acrylic resin or a styrene-maleic acid-based resin is provided on a plastic base material, and a printing layer arranged on the undercoat layer is removed with alkaline water.
In Patent Document 2, a technique is provided in which a primer layer formed of an aqueous primer composition containing a urethane resin and a hydrazine compound is provided on a plastic base material, and the printing layer arranged on the primer layer is removed with alkaline water. It is disclosed.
However, these are techniques that only remove the front printing ink layer on the outside of the package, and have not yet removed the back printing ink layer in the laminated laminate to separate the base materials from each other.
Further, these primer layers are formed of an aqueous composition in order to increase the solubility in a basic aqueous solution, and in order to improve the production efficiency, the drying temperature is lowered or the printing speed is increased. In this case, there is a problem that the primer layer is poorly dried, and the image quality of the print layer is poor, such as a decrease in print density and a decrease in pattern reproducibility.

Therefore, in packaging materials with excellent image quality of printed layers, in addition to removing the printed layer on the outside of the package for plastic recycling, the technology for removing the printed layer on the inside of the package, which is a laminated laminate, promotes plastic recycling. In addition, it is an important technology that can be used industrially for environmental protection, but a technology that can achieve both of these has not yet been reported.

Japanese Unexamined Patent Publication No. 2001-131484 JP-A-2017-114930

Therefore, the subject of the present invention is a packaging material having excellent image quality of the print layer, and it is possible to remove not only the print layer on the outer side of the package but also the print layer on the inner side, and the print base material is excellent in detachability. , To provide packaging materials and packaging containers suitable for plastic recycling.

The present invention relates to the following inventions [1] to [10].

[1] A packaging material provided with at least a first base material, a primer layer for desorbing the first base material, and a printing layer in this order.
The primer layer contains a cured product of a hydroxyl group-containing resin and polyisocyanate, and contains
A packaging material in which the primer layer is provided in contact with the first base material.

[2] A packaging material provided with at least a first base material, a primer layer for desorbing the first base material, a printing layer, and a second base material in this order.
The primer layer contains a cured product of a hydroxyl group-containing resin and polyisocyanate, and contains
A packaging material in which the primer layer is provided in contact with the first base material.

[3] The packaging material according to [1] or [2], wherein the hydroxyl group-containing resin is a urethane resin.

[4] The item according to any one of [1] to [3], wherein the urethane resin contains a structural unit derived from at least one polyol selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols. Packaging material.

[5] The packaging material according to [4], wherein the polyol contains 50% by mass or more of a polyester polyol having an ester bond concentration of 4 to 11 mmol / g.

[6] The packaging material according to any one of [3] to [5], wherein the urethane resin has a molecular weight distribution (Mw / Mn) of 6.0 or less.

[7] The primer layer further contains at least one resin selected from the group consisting of cellulose resin, vinyl chloride resin, rosin resin, acrylic resin and styrene-maleic acid copolymer resin [1] to [ 6] The packaging material according to any one of the items.

[8] The packaging material according to any one of [1] to [7], wherein the primer layer further contains an extender pigment.

[9] A packaging container in which at least a part thereof is formed of the packaging material according to any one of [1] to [8].

[10] A method for producing a recycled base material, which comprises a step of immersing the packaging material according to any one of [1] to [8] or the packaging container according to [9] in a basic aqueous solution.
A method for producing a recycled base material, wherein the basic aqueous solution contains 0.5 to 20% by mass of the total basic aqueous solution, and the water temperature of the basic aqueous solution at the time of immersion is 25 to 120 ° C.

INDUSTRIAL APPLICABILITY According to the present invention, it is a packaging material having excellent image quality of a printing layer, and it is possible to remove not only the printing layer on the outer side of the package but also the printing layer on the inner side, and the printing base material is excellent in detachability, for plastic recycling. Suitable packaging materials and packaging containers can be provided.

The embodiments of the present invention will be described in detail below, but the description of the embodiments or requirements described below is an example of the embodiments of the present invention, and the present invention includes these contents as long as the gist thereof is not exceeded. Not limited.

The packaging material of the present invention is a packaging material provided with at least a first base material, a primer layer for desorbing the first base material, and a printing layer in this order, and the primer layer is a hydroxyl group-containing resin. It is characterized in that it contains a cured product of polyisocyanate and the primer layer is provided in contact with the first base material.
Further, the packaging material of the present invention is a packaging material provided with at least a first base material, a primer layer for desorbing the first base material, a printing layer and a second base material in this order. The primer layer contains a cured product of a hydroxyl group-containing resin and a polyisocyanate, and the primer layer is provided in contact with the first base material.

In the packaging material, the primer layer is dissolved and peeled off with a basic aqueous solution or the like, so that the first base material is detached and the first base material can be separated and recovered. Therefore, the packaging material of the present invention corresponds to the packaging material used for separating and recovering the first base material. Further, since the urethane crosslinked structure is introduced into the primer layer, the packaging material suppresses the penetration and bleeding of the printing layer formed on the primer layer, and can exhibit excellent image quality.
The present invention will be described in detail below, but these are examples of embodiments of the present invention, and the present invention is not limited to these contents as long as the gist thereof is not exceeded.

<Primer layer for desorbing the first substrate>
The primer layer in the present invention is arranged in contact with the first base material, and is a layer for desorbing the first base material by dissolution, peeling, etc. using a basic aqueous solution, and is a layer for desorbing the first base material, and is a hydroxyl group-containing resin. Contains a cured product with polyisocyanate. Specifically, the primer layer preferably contains a cured product of a primer composition containing a hydroxyl group-containing resin and polyisocyanate, and is formed on the primer layer by introducing a urethane crosslinked structure by a curing reaction. Penetration and bleeding of the print layer are suppressed, and excellent image quality is exhibited.

<Hydroxy group-containing resin>
The hydroxyl group-containing resin is not particularly limited and can be selected from conventionally known resins, and may be used alone or in combination of two or more.
Examples of the resin skeleton of the hydroxyl group-containing resin include acrylic resin, urethane resin, polyester resin, rosin resin, amino resin, phenol resin, epoxy resin, and cellulose, which are preferable because they have good laminating suitability. Is.

[Hydroxy group-containing urethane resin]
The hydroxyl value of the hydroxyl group-containing urethane resin is preferably 1 to 35 mgKOH / g, and more preferably 10 to 30 mgKOH / g. When it is 1 mgKOH / g or more, it is preferable because the desorption property by a basic aqueous solution is good, and when it is 35 mgKOH / g or less, it is preferable because the substrate adhesion is good.
The acid value of the hydroxyl group-containing urethane resin is preferably 15 mgKOH / g or more, more preferably 15 to 70 mgKOH / g, and even more preferably 20 to 50 mgKOH / g. When it is 15 mgKOH / g or more, it is preferable because the desorption property by a basic aqueous solution is good, and when it is 70 mgKOH / g or less, it is preferable because the substrate adhesion and the retort resistance are good.
Both the hydroxyl value and the acid value are values measured according to JIS K0070.

The weight average molecular weight of the hydroxyl group-containing urethane resin is preferably 10,000 to 100,000, more preferably 15,000 to 70,000, and even more preferably 15,000 to 50,000.
The molecular weight distribution (Mw / Mn) of the hydroxyl group-containing urethane resin is preferably 6 or less. Mw represents the weight average molecular weight and Mn represents the number average molecular weight. When the molecular weight distribution is 6 or less, the influence caused by the excessive high molecular weight component, the unreacted component, the side reaction component and other low molecular weight components can be avoided, and the desorption property and the drying property of the primer composition can be avoided. Good retort resistance.

Further, the smaller the molecular weight distribution, that is, the sharper the molecular weight distribution, the more uniformly the dissolution / peeling action of the basic aqueous solution occurs and the detachability of the first base material is improved, which is preferable. The molecular weight distribution is more preferably 5 or less, still more preferably 4 or less. The molecular weight distribution is preferably 1.5 or more, more preferably 1.2 or more.
Mw, Mn and the molecular weight distribution (Mw / Mn) are polystyrene-equivalent values obtained by gel permeation chromatography (GPC).
When the molecular weight distribution and the acid value are within the above ranges, not only the desorption property by the basic aqueous solution but also the drying property, the substrate adhesion and the retort resistance of the primer composition are improved, which is preferable.

The hydroxyl group-containing urethane resin may have an amine value. When the hydroxyl group-containing urethane resin has an amine value, the amine value is preferably 0.1 to 20 mgKOH / g, more preferably 1 to 10 mgKOH / g. When it is within the above range, the adhesion to the base material is good, which is preferable.

The hydroxyl group-containing urethane resin is not particularly limited, and is preferably a resin obtained by reacting a polyol, a hydroxy acid, and a polyisocyanate, for example. By using a hydroxy acid, an acid value can be imparted to the urethane resin, and desorption property can be improved. More preferably, it is a resin obtained by reacting a resin obtained by reacting a polyol, a hydroxy acid and a polyisocyanate with a polyamine.

(Polyol)
Polyol is a general term for compounds having at least two hydroxyl groups in one molecule, and does not contain hydroxy acids, which will be described later.
The number average molecular weight of the polyol is preferably 500 to 10,000, more preferably 1,000 to 5,000. The number average molecular weight referred to here is calculated from the hydroxyl value of the polyol, and the hydroxyl value is a value measured by JISK0070. When the number average molecular weight of the polyol is 500 or more, the flexibility of the primer layer is excellent and the adhesion to the first substrate is improved. When the number average molecular weight is 10,000 or less, the blocking resistance to the first substrate is excellent.

The polyol is not particularly limited, and more preferably, at least one polyol selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols is used. Further, the polyol may also contain other dimer diols, hydrogenated dimer diols, castor oil-modified polyols and the like.
That is, the hydroxyl group-containing urethane resin in the present invention preferably contains a structural unit derived from at least one polyol selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols. Since the ester bond site of the polyester polyol is alkaline hydrolyzed to improve the desorption property, it more preferably contains a constituent unit derived from the polyester polyol.
The content of the constituent unit derived from the polyol is preferably 10 to 75% by mass, more preferably 15 to 70% by mass, and further preferably 20 to 65% by mass with respect to the total amount of the hydroxyl group-containing urethane resin. The content of the constituent units derived from the polyester polyol is preferably 5% by mass or more, more preferably 30% by mass or more, still more preferably 60% by mass or more, and particularly preferably 80% by mass, based on the total amount of the constituent units derived from the polyol. That is all.

[Polyester polyol]
Examples of the polyester polyol include a polyester polyol composed of a condensate of a dibasic acid and a diol; a polyester polyol composed of a polylactone polyol which is a ring-opening polymer of a cyclic ester compound; and a polyester diol is preferable. The polyester polyol can be used alone or in combination of two or more.
Dibasic 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, with adipic acid or succinic acid being preferred.

Examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol (hereinafter referred to as propylene glycol), 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, and 1,6-. Hexanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 3,3,5-trimethyl Pentandiol 2,4-diethyl-1,5-pentanediol, 1,12-octadecanediol, 1,2-alkanediol, 1,3-alkanediol, 1-monoglyceride, 2-monoglyceride, 1-monoglycerin ether , 2-Monoglycerin ether, dimerdiol, hydrogenated dimerdiol and the like.

As the polyester diol, a condensate of a dibasic acid and a diol having a branched structure may be used. It is preferable to use a diol having a branched structure because the adhesion to the plastic base material and the retort resistance can be improved.
The diol having a branched structure is preferably a diol having a structure in which at least one hydrogen atom of the alkylene glycol is substituted with an alkyl group, and is, for example, 1,2-propanediol, 1,3-butanediol, or 2-methyl. -1,3-propanediol, neopentyl glycol, 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-pentane Examples thereof include diols and 2,2,4-trimethyl-1,6-hexanediols. Of these, at least one selected from the group consisting of 1,2-propanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, and 2-butyl-2-ethyl-1,3-propanediol is preferable. Therefore, 1,2-propanediol or 3-methyl-1,5-pentanediol is preferably used.

As the raw material of the polyester polyol, a polyol having 3 or more hydroxyl groups and a polyvalent carboxylic acid having 3 or more carboxyl groups may be used in combination.
Preferable examples of the cyclic ester compound include α-acetolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone.

The polyol in the present application contains 50% by mass or more of the polyester polyol having an ester bond concentration of 4 to 11 mmol / g in the total mass of the polyol in order to improve the peelability of the primer layer and facilitate the desorption of the first base material. It is preferable to contain it. The ester bond concentration is more preferably 7 to 11 mmol / g, still more preferably 8 to 11 mmol / g, and particularly preferably 9 to 11 mmol / g.

Here, the ester bond concentration is a value represented by the following formula (1).
Formula (1): Ester bond concentration (mmol / g) = total number of moles of ester bonds in polyester polyol (mmol) / total solid content mass (g) of polyester polyol

When the polyester polyol is a polyester polyol obtained by polycondensing dibasic acid and diol as described above, the ester bond concentration is represented by the following formula (2) based on the amount of dibasic acid used for the polycondensation. Can be calculated.
Formula (2): Ester bond concentration (mmol / g) = total number of moles of carboxyl groups of dibasic acid (mmol) / total solid mass of polyester polyol (g)

The polyester polyol having such a specific ester bond concentration preferably has a structural unit represented by the following general formula (1).

General formula (1)

In the general formula (1), R ¹ and R ² are independently substituted or unsubstituted alkylene groups having 1 to 10 carbon atoms, and may be the same or different from each other. n is a natural number.
The linear carbon number of the alkylene group in R ¹ and R ² is preferably 1 to 6 and more preferably 1 to 3 independently of each other.
The linear carbon number of the alkylene group referred to here is a carbon number that does not include carbon contained in the branched structure or the substituent. For example, in the case of 3-methyl-1,5-pentanediol, the linear carbon number is In the case of 2-butyl-2-ethyl-1,3-propanediol, the number of linear carbon atoms is 3.

Polyester polyols having a structural unit represented by the general formula (1) include, for example, dibasic acids such as adipic acid, succinic acid and sebacic acid, and 1,2-propanediol (propylene glycol) and 1,3-butane. It can be obtained by polycondensation with a diol such as diol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol.

[Polyether polyol]
Examples of the polyether polyol include polymers or copolymers such as methylene oxide, ethylene oxide, propylene oxide, and tetrahydrofuran, and specific examples thereof include polyethylene glycol, polypropylene glycol, polytrimethylene glycol, and polytetramethylene glycol. , Or a copolymer thereof, more preferably polyethylene glycol, polypropylene glycol, or polytetramethylene glycol. These can be used alone or in combination of two or more.

[Polycarbonate polyol]
As the polycarbonate polyol, those containing an aliphatic polycarbonate polyol are preferable. The number average molecular weight of the polycarbonate polyol is preferably 500 to 5,000, more preferably 800 to 4,000, and even more preferably 1,000 to 3,000.

The aliphatic polycarbonate polyol preferably contains a structural unit derived from an aliphatic diol such as a substituted or unsubstituted alkylene glycol, and the method for producing the aliphatic polycarbonate polyol is not limited, but the aliphatic diol and the carbonate compound are used. It is preferably a polycondensate produced by a transesterification reaction.

The aliphatic diol preferably has 4 to 10 carbon atoms, and for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and the like. 2-Methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl -1,8-octanediol, 1,10-decanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butinediol, 2,2,4-trimethyl-1,3-pentane Examples thereof include diol, 1,4-cyclohexanedimethanol, diethylene glycol, polypropylene glycol, dipropylene glycol and the like. The substituent contained in the aliphatic diol is preferably an alkyl group having 10 or less carbon atoms. These aliphatic diols can be used alone or in combination of two or more.

The carbonate compound is not particularly limited, and examples thereof include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, and dibutyl carbonate; diaryl carbonates such as diphenyl carbonate; and alkylene carbonates such as ethylene carbonate. Since it becomes a polycondensate in the transesterification reaction with the aliphatic diol and is replaced, the structure of the carbonate compound is not limited, and a compound having good reactivity may be appropriately selected.

The polycarbonate polyol is preferably liquid at 25 ° C. By using a liquid polycarbonate polyol as a raw material for a polyurethane resin, flexibility and elasticity are given to the primer layer, adhesion to a base material is improved, and retort suitability and blocking resistance are improved.
Examples of such a liquid polycarbonate polyol include an alkylene glycol having an odd number of carbon atoms and having a linear structure and an alkylene glycol having an even number of carbon atoms and having a linear structure (linear diol) as an aliphatic diol component. And, an aliphatic polycarbonate diol using, or an aliphatic polycarbonate polyol using an alkylene glycol (branched diol) having an alkyl substituent can be preferably mentioned.

It is preferable that the aliphatic polycarbonate polyol contains a structural unit derived from a branched diol having a tertiary carbon as an aliphatic diol component because the desorption property and the blocking resistance are improved.
Examples of the branched diol having a tertiary carbon include 1,2-propanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, and 2-methyl-1,8-octane. Examples thereof include diols and 2,2,4-trimethyl-1,3-pentanediol, preferably 3-methyl-1,5-pentanediol.
More preferably, a linear diol and a branched diol having a tertiary carbon are used in combination, and an aliphatic polycarbonate polyol using 1,6-hexanediol and 3-methyl-1,5-pentanediol is used. Especially preferable.
The mass ratio (linear diol: branched diol having tertiary carbon) to the total mass of the aliphatic polycarbonate polyol is preferably 70:30 to 5:95, and more preferably 50:50 to 10:90.

(Hydroxy acid)
The hydroxy acid in the present invention refers to a compound having both a hydroxyl group as an active hydrogen group and an acidic functional group in one molecule.
The acidic functional group indicates a functional group that can be neutralized with potassium hydroxide when measuring the acid value, and specific examples thereof include a carboxyl group and a sulfonic acid group, and a carboxyl group is preferable. Since the probability that the acidic group reacts with the isocyanate group is low, the acid value can be maintained even when a hydroxyl group-containing urethane resin is used.
The hydroxy acid is not particularly limited, and for example, dimethylolalkanoic acid such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid is preferably used. These can be used alone or in combination of two or more.

(Polyisocyanate)
The polyisocyanate is not particularly limited and can be selected from conventionally known polyisocyanates, preferably containing diisocyanate or triisocyanate, and more preferably containing aromatic, aliphatic or alicyclic diisocyanate. These may be used alone or in combination of two or more.

Examples of aromatic, aliphatic or alicyclic diisocyanates include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, and 4,4'-dibenzylisocyanate. , Dimethyldiphenylmethane diisocyanate, tetramethyldiphenylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, o-xylylene diisocyanate and 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 2,6-tolylene diisocyanate; tetramethylene diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate Alibo diisocyanates such as: cyclohexane-1,4-diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methyl Examples thereof include cyclohexanediisocyanate, m-tetramethylxylylene diisocyanate, and alicyclic diisocyanate such as dimerged isocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group.

Among them, from the viewpoint of reactivity, preferably from isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane-4,4'-diisocyanate. At least one selected from the group of The diisocyanate is also preferably a triisocyanate having a trimer structure such as an isocyanurate structure.

(Polyamine)
The polyamine in the present invention is not particularly limited, and is preferably a diamine compound.
Examples of the diamine compound include ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, and dimerdiamine obtained by converting the carboxyl group of dimer acid into an amino group. These can be used alone or in combination of two or more.
More preferably, hydroxyl groups such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. It is a diamine having. By using a diamine having a hydroxyl group, a certain amount of the hydroxyl group can remain unreacted, and the hydroxyl value can be introduced into the urethane resin.

Amino acids can be used as the diamine compound. Amino acid refers to a compound having both an amino group and an acidic functional group in one molecule, and examples thereof include glutamine, asparagine, lysine, diaminopropionic acid, ornithine, diaminobenzoic acid, and diaminobenzenesulfonic acid. Since the acidic group has a low probability of reacting with the isocyanate group, the acid value can be maintained in the polyurethane resin.

When reacting the polyamine, a polymerization inhibitor may be used in combination. Examples of the polymerization terminator include dialkylamine compounds such as di-n-dibutylamine; monoethanolamine, diethanolamine, butanolamine, 2-amino-2-methyl-1-propanol, tri (hydroxymethyl) aminomethane, and the like. Hydroxyl groups such as 2-amino-2-ethyl-1,3-propanediol, N-di-2-hydroxyethylethylenediamine, N-di-2-hydroxyethylpropylenediamine, N-di-2-hydroxypropylethylenediamine Amine compounds having; examples include monoamine-type amino acid compounds such as glycine, alanine, glutamic acid, taurine, aspartic acid, aminobutyric acid, valine, aminocaproic acid, aminobenzoic acid, aminoisophthalic acid, sulfamic acid. In order to introduce the hydroxyl value into the polyurethane resin, it is preferable to use an amine compound having a hydroxyl group.

[Manufacturing of hydroxyl group-containing urethane resin]
As described above, the hydroxyl group-containing urethane resin is more preferably a resin obtained by reacting a polyol, a hydroxy acid, and a polyisocyanate with a urethane prepolymer having an isocyanate group at the terminal, and further reacting a polyamine to extend the chain. In this case, in the reaction of the polyol, the hydroxy acid and the polyisocyanate (hereinafter referred to as the urethanization step), the functional group molar ratio (NCO / OH) of the polyisocyanate and the polyol and the hydroxy acid is preferably 1.05 to 3. It is .0, more preferably 1.1 to 2.8. The functional group molar ratio (amino group / NCO) of the isocyanate group of the urethane prepolymer and the amino group of the polyamine is preferably 0.7 to 1.3.

The number of urethane bonds of the hydroxyl group-containing polyurethane resin is preferably 1 to 3 mmol / g, and more preferably 1.5 to 2 mmol / g. The number of urea bonds in the hydroxyl group-containing polyurethane resin is preferably 0 to 3 mmol / g, more preferably 0.2 to 1 mmol / g. The total number of urethane bonds and urea bonds is preferably 1 to 6 mmol / g, and more preferably 1.7 to 3 mmol / g.
It is preferable to set the number of urethane bonds and the number of urea bonds in the corresponding ranges because desorption and substrate adhesion are improved.

The number of urethane bonds is a value represented by the following formula (3) when (number of NCO moles / number of OH moles)> 1 in the urethanization reaction step, and (number of NCO moles / number of OH moles) ≤ 1. In the case, it is a value represented by the following equation (4).
Formula (3): Number of urethane bonds (mmol / g) = Total number of moles of hydroxyl groups (mmol) / Total mass of solids (g)
Formula (4): Number of urethane bonds (mmol / g) = Total number of moles of isocyanate groups (mmol) /
Total solid mass (g)
In the formulas (3) and (4), the total number of moles of hydroxyl groups represents the total number of moles of hydroxyl groups of the polyol and hydroxyic acid used in the urethanization step, and the total solid content is the total number of non-volatile components of the polyurethane resin. Represents the mass, and the total number of moles of isocyanate groups represents the total number of moles of isocyanate groups contained in the polyisocyanate.

The urea bond number is a value applied to those subjected to the urethanization reaction under the condition of (NCO molar number / OH molar number)> 1.
The urea bond number is a value represented by the following formula (5) when (number of moles of amino groups / number of moles of NCO)> 1 in the urea conversion reaction step (number of moles of amino groups / number of moles of NCO) ≤ 1. In the case of, it is a value represented by the following equation (6).
Formula (5): Number of urea bonds (mmol / g) = [total number of moles of isocyanate groups (mmol) -total number of moles of hydroxyl groups (mmol)] / total solid mass (g)
Formula (6): Number of urea bonds (mmol / g) = Total number of moles of amino groups (mmol) / Total mass of solids (g)
In the formulas (5) and (6), the total number of moles of isocyanate groups represents the total number of moles of isocyanate groups contained in the polyisocyanate used in the urethanization step, and the total number of moles of hydroxyl groups is the polyol used in the urethanization step and the number of moles of hydroxyl groups. The total number of moles of hydroxyl groups contained in hydroxyic acid and the like is represented by the total number of moles of amino groups, and the total number of moles of amino groups represents the total number of moles of primary and / or secondary amino groups possessed by the polyamine used in the ureation reaction step. The mass represents the total mass of the non-volatile components of the polyurethane resin.

<Polyisocyanate>
The polyisocyanate constituting the primer layer is not particularly limited and can be selected from conventionally known polyisocyanates, and examples thereof include aliphatic polyisocyanates and aromatic aliphatic polyisocyanates. These may be used alone or in combination of two or more.

As the aliphatic polyisocyanate, well-known aliphatic diisocyanates, alicyclic diisocyanates, aromatic aliphatic diisocyanates or derivatives thereof can be used.
Examples of the aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4. Alibo diisocyanates such as 4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl caproate; 1,4-cyclohexanediisocyanate, 1,3-cyclohexanediisocyanate, 3-isocyanatomethyl-3 , 5,5-trimethylcyclohexylisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), methyl2,4-cyclohexanediisocyanate, methyl2,6-cyclohexanediisocyanate, 1,4-bis (isocyanatemethyl) cyclohexane, 1,3 -Alicyclic diisocyanate such as bis (isocyanate methyl) cyclohexane; 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,3- or 1, Arophilic diisocyanates such as 4-bis (1-isocyanate-1-methylethyl) benzene or a mixture thereof; allophanate-type, nurate-type, biuret-type, adduct-type derivatives, or complexes thereof derived from the above diisocyanates, etc. Polyisocyanate; etc.

As the aromatic polyisocyanate, a well-known aromatic diisocyanate or a derivative thereof can be used.
Examples of the aromatic diisocyanate include toluene diisocyanate, diphenylmethane diisocyanate, and allophanate-type, nurate-type, biuret-type, and adduct-type derivatives derived from the above-mentioned diisocyanate, or complexes thereof.

The polyisocyanate is preferably an adduct-type polyisocyanate (hereinafter, adduct), a biuret-type polyisocyanate (hereinafter, biuret), or a diphenylmethane diisocyanate (hereinafter, MDI) or hexamethylene diisocyanate (hereinafter, HDI). Isocyanurate-type polyisocyanate (hereinafter referred to as isocyanurate), more preferably a trimethylolpropan adduct (HDI-TPM), biuret, or isocyanurate derived from hexamethylene diisocyanate.

[Other ingredients]
The primer layer may further contain other components. Other components may be blended with either the hydroxyl group-containing resin or the polyisocyanate, or may be added when the hydroxyl group-containing resin and the polyisocyanate are blended.

(Other resins)
The primer layer may further contain a resin other than the hydroxyl group-containing resin.
Examples of other resins include vinyl chloride resins such as cellulose resins, polyamide resins, vinyl chloride-vinyl acetate copolymer resins or vinyl chloride-acrylic copolymer resins, rosin resins, ethylene-vinyl acetate copolymer resins, and acetic acid. Vinyl resin, acrylic resin, styrene resin, dammar resin, styrene-maleic acid copolymer resin, styrene-acrylic copolymer resin, polyester resin, alkyd resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, rubber chloride , Butyral, polyacetal resin, petroleum resin, and modified resins thereof. These resins may be used alone or in combination of two or more.
Above all, the primer layer preferably contains at least one resin selected from the group consisting of cellulose resin, vinyl chloride resin, rosin resin, acrylic resin and styrene-maleic acid copolymer resin. It is still preferable that the resin is at least one selected from the group consisting of vinyl chloride-based resins, styrene-maleic acid copolymer resins, and rosin-based resins. The vinyl chloride resin has excellent compatibility when a urethane resin is used as the main resin, and is preferably used for the purpose of imparting coating film strength. More preferably, it is particularly preferable to use a rosin-based resin, a dibasic acid-modified resin of rosin, a styrene maleic acid copolymer resin, and an acrylic resin containing acrylic acid and methacrylic acid in combination. These resins have an acid value, are hydrophilic, and are excellent in swelling property and solubility in an alkaline aqueous solution, and thus are advantageous in desorption. The acid value of the resin is preferably 100 mgKOH / g or more, and more preferably 150 mgKOH / g or more.
The resin is preferably contained in either or both of the primer layer and the printing layer. When it is contained in the primer layer, the primer layer has excellent swelling property and desorption property to the alkaline solution, so that the desorption property is improved, and when it is contained in the printing layer, the hydrophilicity of the peeled printing layer is improved. It is preferable that the printed layer peeled pieces can be prevented from reattaching to the isolated transparent substrate, and the transparent substrate having high purity can be recycled.
The mass ratio of the hydroxyl group-containing urethane resin to the other resin (hydroxyl group-containing urethane resin: other resin) is preferably 95: 5 to 50:50. Within the above range, when the print layer is peeled off together with the primer layer in the basic aqueous solution, the print layer is peeled off in a thin film state, which is preferable because recovery is easy.

(Constitution pigment)
The primer layer preferably contains an extender pigment from the viewpoint of improving the film strength, improving the optical properties, and improving the fluidity of the primer composition.
Examples of the extender pigment include metal oxides such as silica, barium sulfate, kaolin, clay, calcium carbonate, magnesium carbonate, zinc oxide, and zirconium oxide. These are used to improve fluidity, film strength, optical properties, and image quality when overprinting printing inks. Of these, the use of silica and barium sulfate is preferable. When it is silica, it is preferably hydrophilic. In the case of barium sulfate, it is preferably precipitated barium sulfate. The extender pigment preferably has an average particle size of 0.5 to 10 μm, and more preferably 1 to 8 μm. The extender pigment is preferably contained in an amount of 0.5 to 30% by mass, and more preferably 1 to 25% by mass in the total amount of the ink. Further, silica is preferably 1 to 5% by mass, and barium sulfate is preferably 10 to 25% by mass.

<Primer composition>
The primer composition can be produced by dissolving and / or dispersing at least a hydroxyl group-containing resin and polyisocyanate in an organic solvent, and may contain the above-mentioned other components, if necessary.
Examples of the organic solvent include aromatic organic solvents such as toluene and xylene; ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester organic solvents such as ethyl acetate, n-propyl acetate, isopropyl acetate and isobutyl acetate. Known organic solvents such as alcohol-based organic solvents such as methanol, ethanol, n-propanol, isopropanol, and n-butanol; glycol ether-based solvents such as ethylene glycol monopropyl ether and propylene glycol monomethyl ether; Alternatively, two or more types can be mixed and used.

The content of polyisocyanate in the primer composition is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, still more preferably, based on the total amount of solids in the composition. Is 1 to 7% by mass. When it is within the above range, penetration and bleeding of the print layer formed on the primer layer are suppressed, and excellent image quality is exhibited, which is preferable.

The solid content concentration in the primer composition is preferably 5 to 50% by mass, more preferably 10 to 40% by mass. Further, the content of the hydroxyl group-containing resin in the primer composition is preferably 0.5 to 50% by mass, more preferably 5 to 30% by mass. Optimal printability can be obtained within the above range.
The viscosity of the primer composition is preferably 20 to 500 mPa · s, more preferably 30 to 300 mPa · s, because appropriate printability can be obtained in the printing process. The viscosity of the primer composition can be appropriately adjusted depending on the content of the hydroxyl group-containing resin and the polyisocyanate, the content of other components described later, and the like.

The primer composition may further contain known additives. Known additives include dispersants, wetting agents, adhesion aids, leveling agents, defoamers, antistatic agents, viscosity modifiers, metal chelates, trapping agents, blocking inhibitors, wax components other than the above, and silane cups. Ring agents and the like can be mentioned. Further, the primer composition preferably contains an anti-fog agent, a hydrophilic agent, and an antistatic agent as additives. The anti-fog agent, hydrophilic agent, and antistatic agent may include those conventionally known as additives to be added to general films and coating agents for the purpose of imparting anti-fog property, hydrophilic property, and antistatic property. can. Specific preferred examples include glycerin fatty acid ester, phosphoric acid ester, and quaternary ammonium salt.
Moreover, it is preferable that the additive is contained in either or both of the primer layer and the printing layer.
When it is contained in the primer layer, the hydrophilicity of the primer layer is improved, so that neutralization, swelling, dissolution, etc. by the alkaline solution proceed quickly, so that the desorption property is improved. When it is contained in the print layer, the hydrophilicity of the peeled print layer is improved and the dispersibility in the alkaline aqueous solution is improved, so that the reattachment of the print layer peeled piece to the transparent substrate can be prevented and the purity is high. Suitable for isolating a transparent substrate.

<First base material>
Examples of the first base material include a plastic base material on a film or sheet that is generally used for packaging materials, a gas barrier base material such as a metal foil, paper, and the like, and even if these are laminated. good.
Examples of the plastic base material include a film of a thermoplastic resin and a thermosetting resin, and a film of a thermoplastic resin is preferable. Examples of the thermoplastic resin include polyolefin resins, polyester resins, polyamide resins, polystyrene resins, vinyl chloride resins, vinyl acetate resins, ABS resins, acrylic resins, acetal resins, polycarbonate resins, and fibrous plastics.

More specifically, polyolefin resin films such as polyethylene (PE), biaxially stretched polypropylene (OPP); polyester resin films such as polyethylene terephthalate, polyethylene naphthalate (PEN), polylactic acid (PLA); Polyethylene resin films such as nylon 6, poly-p-xylylene adipamide (MXD6 nylon); polycarbonate resin films; polyacrylic nitrile resin films; polyimide resin films; these multilayers (eg, nylon 6 / MXD6 / Nylon 6, nylon 6 / polyethylene-vinyl alcohol copolymer / nylon 6), a mixture; and the like are used. Among them, those having mechanical strength and dimensional stability are preferable.
The thickness of the plastic film is preferably 5 μm or more and 200 μm or less, more preferably 10 μm or more and 100 μm or less, and further preferably 10 μm or more and 50 μm or less.

Examples of the gas barrier base material include aluminum foil; a plastic base material having an inorganic vapor-deposited layer such as aluminum, silica, and alumina; and a plastic base material having an organic layer such as polyvinyl alcohol. In the case of aluminum foil, a thickness in the range of 3 to 50 μm is preferable from the economical point of view. Commercially available products of plastic substrates having an inorganic vapor deposition layer include, for example, "GL FILM" (manufactured by Toppan Printing Co., Ltd.) in which an inorganic vapor deposition layer such as alumina is laminated on a plastic substrate, and IB-FILM (Dai Nippon Printing Co., Ltd.). (Made by Nippon Printing Co., Ltd.) and the like. Since aluminum and alumina have solubility in a basic aqueous solution, they can be dissolved in a desorption step described later and only the plastic base material can be recycled.

If necessary, the plastic base material may be coated or kneaded with additives such as antistatic agents, anti-fog agents, and UV protection agents, or the surface of the base material may be corona-treated or low-temperature plasma-treated. Can be used.
In particular, a plastic film having anti-fog properties obtained by applying or kneading an anti-fog agent to a polypropylene base material or the like has high hydrophilicity of the base material itself, which is advantageous in desorption.

From the viewpoint of reuse as a recycled base material, the first base material preferably contains a polyolefin resin film such as polyethylene and biaxially stretched polypropylene.

When the first base material is a laminated body, it is preferable that the base materials are laminated via an adhesive layer. The method for forming the adhesive layer is not limited, and a known adhesive can be used to form the adhesive layer by a known method.

<Print layer>
The printing layer in the present invention is a layer provided in contact with the primer layer on the side opposite to the first base material of the primer layer, and is used for decoration, aesthetics, contents, expiration date, manufacturer or seller. It is a layer for forming an arbitrary printing pattern for the purpose of displaying the above, and also includes a solid printing layer. The printing layer can be provided, for example, between the primer layer and the adhesive layer, and may be provided on the entire surface or a part of the primer layer.
The printing layer can be formed by using a conventionally known pigment or dye, and may be formed by using a printing ink containing the pigment or dye, and the forming method thereof is not particularly limited. The print layer may be formed of a single layer or a plurality of layers.
The thickness of the printing layer is preferably 0.1 μm or more and 100 μm or less, more preferably 0.1 μm or more and 10 μm or less, and further preferably 1 μm or more and 5 μm or less.

Examples of the printing ink for forming the printing layer include printing inks containing a medium such as a pigment, a binder, a solvent, or water. Examples of the binder include fiber materials such as nitrocellulose, cellulose acetate / propionate, chlorinated polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, acrylic, polyurethane and acrylic urethane, and polyamide. Polybutyral-based, cyclized rubber-based, chloride-rubber-based, or a binder in which they are appropriately used can be used. Further, as described above, for the purpose of increasing the hydrophilicity of the printed layer peeled piece, conventionally known antifogging agents, hydrophilic agents, antistatic agents, rosin-based resin dibasic acid-modified resin of rosin, and styrene maleic acid. It can contain a copolymer resin, an acrylic resin containing acrylic acid and methacrylic acid, and the like.

The method of applying the printing ink is not particularly limited, and the printing ink can be applied by a method such as a gravure coating method, a flexographic coating method, a roll coating method, a bar coating method, a die coating method, a curtain coating method, a spin coating method, or an inkjet method. .. The printed layer can be formed by leaving it as it is or, if necessary, by blowing air, heating, drying under reduced pressure, irradiating with ultraviolet rays, or the like.

<Second base material>
The second base material may be, for example, the base material mentioned in the above-mentioned first base material or a sealant base material, and may be a laminated body in which these are laminated. The second base material is preferably a sealant base material and contains polyolefin. The second base material may have a vapor-deposited film of silica, alumina, or the like.
Examples of the sealant base material include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE) and other polyethylene, acid-modified polyethylene, unstretched polypropylene (CPP), and acid-modified polypropylene. Examples thereof include copolymerized polypropylene, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid ester copolymer, ethylene- (meth) acrylic acid copolymer, and ionomer.
From the viewpoint of recyclability, the second base material is the first base material low-density polyethylene, polyethylene such as linear low-density polyethylene or high-density polyethylene, acid-modified polyethylene, unstretched polypropylene, acid-modified polypropylene, copolymerization. Polyethylene and other polyolefins are preferred.
From the viewpoint of retort resistance, polypropylene is preferable, and from the viewpoint of heat sealability, unstretched polypropylene is preferable.

The thickness of the second base material is not particularly limited, and is preferably 10 μm or more and 150 μm or less, and more preferably 20 μm or more and 70 μm or less in consideration of processability to the packaging container or heat sealability. By providing the second base material with irregularities having a height difference of about several μm, slipperiness and tearability of the packaging material can be imparted.
The method of laminating the second base material is not particularly limited, and for example, the printed surface of the laminated film having the first base material, the primer layer and the printing layer and the second base material are bonded to each other by using a laminating adhesive. A method of laminating the resin together; a method of melting the resin constituting the second base material, extruding the resin onto the printing layer, and cooling and solidifying the resin; and the like.

The following is an example of the structure of the packaging material of the present invention, but the present invention is not limited thereto. As described above, the first base material and the second base material may be a laminated body in which a plurality of base materials are laminated.
-First base material / primer layer / printing layer-first base material (laminate) / primer layer / printing layer-first base material / primer layer / printing layer / adhesive layer / second base material -First base material / primer layer / printing layer / adhesive layer / second base material (laminate)

<Packaging container>
The packaging container of the present invention is at least partially formed of the packaging material. By being formed of the packaging material, a packaging container having excellent detachability of the first base material mainly used as a printing base material and suitable for recycling can be obtained.
The type and use of the packaging container of the present invention are not particularly limited, but can be suitably used for, for example, food containers, detergent containers, cosmetic containers, pharmaceutical containers, and the like. The shape of the packaging container is not limited, and it can be molded into a shape according to the contents, and is preferably used for a pouch or the like.

<Recycled base material manufacturing method>
The method for producing a recycled base material of the present invention is
At least, a first base material, a primer layer for desorbing the first base material, and a printing layer are provided in this order, and the primer layer contains a cured product of a hydroxyl group-containing resin and a polyisocyanate, and the first base material is contained. A packaging material in which the primer layer is provided in contact with the base material of the above and a printing layer is provided on the side opposite to the first base material of the primer layer, or formed of the packaging material. The step of immersing the packaging container in a basic aqueous solution is included.
In the present invention, "desorption" means that the first base material is desorbed from the packaging material by neutralizing or dissolving the primer layer with a basic aqueous solution and peeling off, and (1) the primer layer is dissolved. When the first base material is desorbed, (2) even if the primer layer is not dissolved, it is peeled off by neutralization, swelling, etc., and the first base material is desorbed. ..

Since the object of the present invention is to obtain the first base material after desorption as a recycled base material / recycled base material, it is preferable to remove as much primer layer as possible from the first base material. be. Specifically, it is preferable that at least 50% by mass or more of the 100% by mass of the primer layer is desorbed in the area and film thickness direction. It is more preferable that 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more are desorbed.

The basic compound used in the basic aqueous solution is not particularly limited, and is, for example, sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca (OH) ₂ ), ammonia, barium hydroxide (Ba (Ba). OH) ₂ ) and sodium carbonate (Na ₂ CO ₃ ) are preferably used, but are not limited thereto. More preferably, it is at least one selected in the group consisting of sodium hydroxide and potassium hydroxide.
The basic aqueous solution preferably contains a basic compound in an amount of 0.5 to 20% by mass, more preferably 1 to 15% by mass, and particularly preferably 3 to 15% by mass, based on the total amount of the basic aqueous solution. When the concentration is within the above range, the basic aqueous solution can retain sufficient basicity to exfoliate the primer layer by dissolution or swelling to desorb the first base material.

The basic aqueous solution permeates from the end portion of the packaging material or the packaging container, contacts the primer layer, dissolves or swells, and separates the first base material from the primer layer. Therefore, in order to efficiently proceed with the desorption step, it is preferable that the packaging material or the packaging container is in a state where the primer layer is exposed on the cross section when the packaging material or the packaging container is cut or crushed and immersed in a basic aqueous solution. In such a case, the first base material layer can be desorbed in a shorter time.

The temperature of the basic aqueous solution when the packaging material is immersed is preferably 25 to 120 ° C, more preferably 30 to 120 ° C, and particularly preferably 30 to 80 ° C. The immersion time in the basic aqueous solution is preferably 1 minute to 24 hours, more preferably 1 minute to 12 hours, and preferably 1 minute to 6 hours. The amount of the basic aqueous solution used is preferably 1 to 1,000,000 times the mass of the packaging material, and it is preferable to stir or circulate the basic aqueous solution in order to improve the desorption efficiency. The rotation speed is preferably 80 to 250 rpm, more preferably 80 to 200 rpm.

A recycled base material can be obtained through a step of peeling the primer layer together with the printing layer from the packaging material, removing and recovering the first base material, and then washing and drying the first base material with water. The removal rate of the print layer on the surface of the first base material is preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more, based on the area of the print layer before desorption.

Therefore, according to the present invention, the step of immersing the packaging material or the packaging container in the basic aqueous solution, the step of dissolving or peeling the primer layer from the packaging material or the packaging container to remove the first base material, the first step. A recycled base material of the first base material can be obtained by going through a step of recovering the base material and a step of washing and drying the first base material with water. Further, the obtained recycled base material can be processed into pellets by an extruder or the like and reused as a recycled resin.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. The "parts" and "%" in the present invention mean "parts by mass" and "% by mass" unless otherwise specified.

(Molecular weight and molecular weight distribution)
The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) were measured by GPC (gel permeation chromatography) and determined as converted molecular weights using polystyrene as a standard substance. The measurement conditions are shown below.
GPC device: Showa Denko Shodex GPC-104
Column: The following columns were connected in series and used.
Showa Denko Shodex LF-404 2 pieces Showa Denko Shodex LF-G
Detector: RI (Differential Refractometer)
Measurement conditions: Column temperature 40 ° C
Eluent: tetrahydrofuran Flow rate: 0.3 mL / min

(Acid value, hydroxyl value)
The acid value and hydroxyl value were measured according to the method described in JIS K0070 (1992).

<Manufacturing of hydroxyl group-containing resin>
[Synthesis Example 1] (Polyurethane resin P1)
Adipic acid / propane-1,2-diol polymer having a number average molecular weight of 2,000 while introducing nitrogen gas in a reactor equipped with a reflux cooling tube, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer. 159.0 parts (hereinafter, PPA), 27.1 parts of 2,2-dimethylol propanoic acid (hereinafter, DMPA), 99.6 parts of isophorone diisocyanate (hereinafter, IPDI), and 200 parts of methyl ethyl ketone (hereinafter, MEK) are charged. , 90 ° C. for 5 hours to obtain a urethane prepolymer solution having an isocyanate group at the terminal.
Then, a mixture of 13.6 parts of 2- (2-aminoethylamino) ethanol (hereinafter, AEA) and 350 parts of isopropyl alcohol (hereinafter, IPA) was added dropwise at room temperature over 60 minutes, and then at 70 ° C. The reaction was carried out for 3 hours to obtain a hydroxyl group-containing polyurethane resin solution.
MEK was added to the obtained polyurethane resin solution to adjust the solid content, and the solid content concentration was 30%, the weight average molecular weight was 33,000, Mw / Mn = 3.0, the acid value was 37.8 mgKOH / g, and the hydroxyl value was 25. A solution of a hydroxyl group-containing polyurethane resin P1 of .7 mgKOH / g was obtained.

[Synthetic Examples 2-7, Comparative Synthesis Example 1] (Polyurethane Resins P2 to P7, PP1)
A solution of the hydroxyl group-containing polyurethane resins P2 to P7 and PP1 was obtained by the same method as in Synthesis Example 1 except that the raw materials and the charged amounts shown in Table 1 were used. Table 2 shows the resin properties such as Mw and acid value.

[Synthesis Example 8] (Polyurethane resin P8)
While introducing nitrogen gas in a reactor equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer, PPA 209.9 parts, DMPA 27.2 parts, IPDI 63.0 parts, and MEK 200 parts were charged. , 90 ° C. for 5 hours to obtain a polyurethane resin solution having a hydroxyl group at the terminal.
MEK and IPA were added to the obtained polyurethane resin solution to adjust the solid content, and the solid content concentration was 30%, the weight average molecular weight was 41,000, Mw / Mn = 3.6, the acid value was 37.9 mgKOH / g, and the hydroxyl group. A solution of a hydroxyl group-containing polyurethane resin P8 having a value of 9.0 mgKOH / g was obtained.

[Comparative Synthesis Example 2] (Polyurethane Resin PP2)
129.8 parts of PPA, 28.8 parts of PPG, 26.1 parts of DMPA while introducing nitrogen gas in a reactor equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer. 94.4 parts of IPDI and 200 parts of MEK were charged and reacted at 90 ° C. for 5 hours to obtain a prepolymer solution having an isocyanate group at the terminal.
Next, a mixture of 20.9 parts of isophorone diamine (hereinafter, IPDA) and 150 parts of IPA was added dropwise at room temperature over 60 minutes, and then 10.0 parts of 28% ammonia water and 690 parts of ion-exchanged water were gradually added. Then, the carboxyl group in the resin was neutralized to make it water-soluble.
Next, MEK and IPA were distilled off under reduced pressure to obtain a polyurethane resin PP2 having a solid content concentration of 30%, a weight average molecular weight of 44,000, Mw / Mn = 3.8, an acid value of 36.4 mgKOH / g, and a hydroxyl value of 0 mgKOH / g. Was obtained. However, the acid value in PP2 is the value before neutralization.

The abbreviations in Tables 1 and 2 are shown below.
PPA: Polyesterdiol (condensation polymer of adipic acid and 1,2-propanediol number average molecular weight 2,000 ester bond concentration 8.7 mmol / g)
PMPA: Polyesterdiol (condensation polymer of adipic acid and 3-methyl-1,5-pentanediol number average molecular weight 2,000 ester bond concentration 7.1 mmol / g)
PMPS: Polyesterdiol (condensation polymer of sebacic acid and 3-methyl-1,5-pentanediol number average molecular weight 2,000 ester bond concentration 5.9 mmol / g)
PC: Polycarbonate diol PPG having a number average molecular weight of 2,000, which is 3-methyl-1,5-pentanediol / 1,6-hexanediol (mass ratio) of 9/1, and a liquid at 25 ° C. PPG: number average molecular weight 2 000 Polypropylene Glycol DMPA: 2,2-Dimethylolpropanoic Acid IPDI: Isophorone Diisocyanate MEK: Methylethylketone AEA: 2- (2-Aminoethylamino) Ethanol IPDA: Isophorone Diamine IPA: Isophorone Alcohol In Synthesis Example 2, the synthesis conditions such as the dropping amount, dropping rate, temperature control, and stirring rate were adjusted so as to obtain Mw and Mw / Mn shown in Table 2.

<Composition for forming a primer layer>
[Production Example 1] (Primer composition S1)
84 parts of polyurethane resin P1 solution, 5 parts of ethyl acetate (hereinafter referred to as EA), 5 parts of IPA, 3 parts of silica particles (P-73 manufactured by Mizusawa Chemical Co., Ltd .: hydrophilic silica particles having an average particle diameter of 3.8 μm), curing agent A ( 3 parts of HDI-TMP adduct (diluted product with 50% solid content of ethyl acetate) was stirred and mixed with a disper to obtain a primer composition S1.

[Production Examples 2 to 15, Comparative Production Examples 1 to 3] (Primer Compositions S2 to S15, SS1 to SS3)
Primer compositions S2 to S13 and SS1 to SS3 were obtained by the same method as in Production Example 1 except that the raw materials and blending ratios shown in Table 3 were used.

The abbreviations in Table 3 are shown below.
-Vinyl chloride-based resin solution: A solution of vinyl chloride-vinyl acetate copolymer resin (vinyl chloride / vinyl acetate / vinyl alcohol = 88/11/11 (mass ratio)) with a solid content concentration of 30% -Acrylic resin solution: solid Styrene-acrylic copolymer resin solution with a concentration of 30% (weight average molecular weight 40,000, acid value 60 mgKOH / g)
-Rosin-maleic acid resin solution: rosin-maleic acid-modified resin solution with a solid content concentration of 30% and an acid value of 200 mgKOH / g-Hydrophilic agent A: Glycerin mono 12-hydroxystearate-Polyisocyanate curing agent A: HDI-TMP Adduct body 50% solid content ethyl acetate diluted product / polyisocyanate curing agent B: XDI-TMP Adduct body solid content 50% ethyl acetate diluted product
-Carbodiimide hardener C: Carbodilite V-02 manufactured by Nisshinbo
-Silica particles: P-73 manufactured by Mizusawa Industrial Chemicals, Inc. (hydrophilic silica particles with an average particle diameter of 3.8 μm)
-Polyethylene particles: High wax 220P (Mw2,000 low molecular weight polyethylene wax) manufactured by Mitsui Chemicals, Inc.
-Barium sulfate: Variace B30 manufactured by Sakai Chemical Industry Co., Ltd. (average particle size 0.3 μm)

<Ink manufacturing>
[Manufacturing Example A] (Printing Ink R1)
Polyurethane resin solution (KL-593 manufactured by Arakawa Chemical Co., Ltd .: Polyester resin combined with polyester polyether) Solid content concentration 30% Mixed solution of ethyl acetate and isopropanol) 30 parts, Vinyl chloride-vinyl acetate co-weighted resin solution (manufactured by Nisshin Chemical Co., Ltd.) Solverine TAO: 10 parts of ethyl acetate solution with a solid content concentration of 30%, 10 parts of indigo pigment (Rionol Blue FG7330 manufactured by Toyo Color Co., Ltd.), and 20 parts of a mixed solvent of normal propyl acetate and isopropanol were mixed by stirring and mixed using a sand mill. The dispersion treatment was carried out for 20 minutes. Then, 30 parts of a mixed solvent of normal propyl acetate and isopropanol was stirred and mixed to obtain printing ink R1.

[Manufacturing Example B] (Printing Ink R2)
Polyurethane resin solution (KL-593 manufactured by Arakawa Chemical Co., Ltd .: polyester / polyether polyurethane resin solid content concentration 30% mixed solution of ethyl acetate and isopropanol) 20 parts, nitrocellulose resin solution (nitrogen content 11.5% Mw50,000 10 parts of nitrocellulose solid content concentration 30% solution), 10 parts of indigo pigment (Rionol Blue FG7330 manufactured by Toyo Color Co., Ltd.), and 20 parts of a mixed solvent of normal propyl acetate and isopropanol were stirred and mixed, and 20 parts were mixed using a sand mill. Dispersion treatment was performed for 1 minute. Then, 30 parts of a mixed solvent of normal propyl acetate and isopropanol was stirred and mixed to obtain printing ink R2.

[Manufacturing Example C] (Printing Ink R3)
20 parts of polyamide resin solution (30% solid content concentration solution of polyamide resin having a dimer acid-derived structure), 20 parts of nitrocellulose resin solution (30% nitrocellulose solid content solution having a nitrogen content of 11.5% Mw50,000), 10 parts of indigo pigment (Rionol Blue FG7330 manufactured by Toyo Color Co., Ltd.) and 20 parts of a mixed solvent of normal propyl acetate and isopropanol were mixed by stirring and dispersed for 20 minutes using a sand mill. Then, 30 parts of a mixed solvent of normal propyl acetate and isopropanol was further stirred and mixed to obtain printing ink R3.

[Manufacturing Example D] (Printing Ink R4)
40 parts of acrylic resin solution (Mw 40,000, acid value 60 mgKOH / g styrene-acrylic copolymer resin solid content concentration 30% solution), indigo pigment (Rionol Blue FG7330 manufactured by Toyo Color Co., Ltd.), and normal propyl acetate And 20 parts of the mixed solvent of isopropanol were stirred and mixed, and the dispersion treatment was carried out for 20 minutes using a sand mill. Then, 20 parts of a mixed solvent of normal propyl acetate and isopropanol was further stirred and mixed to obtain printing ink R4.

[Manufacturing Example E] (Printing Ink R5)
Polyurethane resin solution (KL-593 manufactured by Arakawa Chemical Co., Ltd .: Polyester resin combined with polyester polyether) Solid content concentration 30% Mixed solution of ethyl acetate and isopropanol) 30 parts, Vinyl chloride-vinyl acetate co-weighted resin solution (manufactured by Nisshin Chemical Co., Ltd.) Solverine TAO: 10 parts of ethyl acetate solution with a solid content concentration of 30%, 10 parts of indigo pigment (Rionol Blue FG7330 manufactured by Toyo Color Co., Ltd.), and 20 parts of a mixed solvent of normal propyl acetate and isopropanol were mixed by stirring and mixed using a sand mill. The dispersion treatment was carried out for 20 minutes. Then, 30 parts of a mixed solvent of normal propyl acetate and isopropanol and 3 parts of a curing agent A were stirred and mixed to obtain printing ink R5.

[Manufacturing Example F] (Preparation of printing ink R6)
Polyurethane resin solution (KL-593 manufactured by Arakawa Chemical Co., Ltd .: Polyurethane resin combined with polyester polyether) Solid content concentration 30% Mixed solution of ethyl acetate and isopropanol) 30 parts, Vinyl chloride-vinyl acetate co-weighted resin solution (manufactured by Nissin Chemical Co., Ltd.) Solverine TAO: Ethyl acetate solution with a solid content of 30%) 20 parts, 50 parts of a mixed solvent of normal propyl acetate and isopropanol, and 3 parts of a chelating agent (Organix TC-100 manufactured by Matsumoto Fine Chemical Co., Ltd.) are mixed by stirring and mixed with a transparent varnish. A printing ink R6 was obtained.

[Manufacturing Example G] (Printing ink R7 created)
Polyurethane resin solution (KL-593 manufactured by Arakawa Chemical Co., Ltd .: Polyester resin combined with polyester polyether) Solid content concentration 30% Mixed solution of ethyl acetate and isopropanol) 25 parts, Vinyl chloride-vinyl acetate co-weighted resin solution (manufactured by Nissin Chemical Co., Ltd.) Solvent TAO: 8 parts of rosin-maleic acid resin solution (solid content concentration 30% ethyl acetate solution), 7 parts of rosin-maleic acid resin solution (solid content concentration 30%, acid value 200 mgKOH / g rosin-maleic acid modified resin solution), indigo pigment (Toyo color) 10 parts of Lionol Blue FG7330 manufactured by the same company and 20 parts of a mixed solvent of normal propyl acetate and isopropanol were mixed by stirring and dispersed for 20 minutes using a sand mill. Then, 30 parts of a mixed solvent of normal propyl acetate and isopropanol and 3 parts of a curing agent A were stirred and mixed to obtain printing ink R7.

[Manufacturing Example H] (Preparation of printing ink R8)
Polyurethane resin solution (KL-593 manufactured by Arakawa Chemical Co., Ltd .: Polyurethane resin combined with polyester polyether) Solid content concentration 30% Mixed solution of ethyl acetate and isopropanol) 28 parts, Vinyl chloride-vinyl acetate copolymer resin solution (manufactured by Nisshin Chemical Co., Ltd.) Solvine TAO: 30% solid content ethyl acetate solution) 10 parts, glycerin mono 12-hydroxystearate 2 parts,
10 parts of indigo pigment (Rionol Blue FG7330 manufactured by Toyo Color Co., Ltd.) and 20 parts of a mixed solvent of normal propyl acetate and isopropanol were mixed by stirring and dispersed for 20 minutes using a sand mill. Then, 30 parts of a mixed solvent of normal propyl acetate and isopropanol and 3 parts of a curing agent A were stirred and mixed to obtain printing ink R8.

<Manufacturing of packaging materials>
In the production of the following packaging materials, the following gravure plates were used for printing the primer composition and the printing ink. The printing speed was 70 m / min.
Primer Composition S1 to S13: Laser 175 Lines / inch 25 μm Solid Plate Printing Ink R1 to R5: Helio 175 Lines / inch Plate Type Compressed 100% to 5% Gradient Pattern Printing Ink R6: Laser 175 Lines / inch 25 μm Solid Plate The thickness of both the primer layer and the printing layer was 0.8 μm. However, the film thickness of the print layer is a value measured in the portion where the gradation pattern is 100%.

[Example 1] (Packaging material L1)
The primer composition S1 and the printing ink R1 were each diluted with a mixed solvent of EA / IPA (mass ratio 70/30) at 25 ° C. of Zahn Cup # 3 (manufactured by Rigo Co., Ltd.) for 15 seconds.
The diluted primer composition S1 and printing ink R1 were printed on an OPP film having a thickness of 20 μm in this order using a gravure two-color printing machine equipped with a gravure plate, dried at 50 ° C., and the first group was printed. A packaging material L1 having a structure of a material layer (OPP) / primer layer / printing layer was obtained.

[Examples 2 to 16, 18 to 22, 47 to 51] (Packaging materials L2 to L16, L18 to L22, L47 to L51)
Packaging materials L2 to L16, L18 to L22, and L47 to L51 were obtained by the same method as the packaging material L1 except that the materials shown in Table 3 were used. For the packaging material L22, a diluted primer composition was printed on the vapor-deposited surface of the VM / OPP film having a thickness of 50 μm.

[Example 17] (Packaging material L17)
Primer composition S1, printing inks R1 and R6, respectively, using a mixed solvent of EA / IPA (mass ratio 70/30), so that it takes 15 seconds at 25 ° C. in Zahn Cup # 3 (manufactured by Rikaisha). Diluted.
The diluted primer compositions S1 and printing inks R1 and R6 were printed on an s-PET film having a thickness of 30 μm in this order using a gravure three-color printing machine equipped with a gravure plate, dried at 50 ° C., and dried. A packaging material L17 having a composition of a first base material layer (s-PET) / primer layer / printing layer (R1 / R6) was obtained.

[Example 23] (Packaging material L23)
Adhesive A (TM-340V / CAT-29B manufactured by Toyo Morton Co., Ltd.) is applied and dried on a PE film having a thickness of 50 μm using a dry laminating machine so that the coating amount becomes 2 g / m ² . A first base material was produced by laminating with a PE film having a thickness of 50 μm.
Then, the primer composition S1 and the printing ink R1 were diluted with a mixed solvent of EA / IPA (mass ratio 70/30) at Zahn cup # 3 at 25 ° C. for 15 seconds, respectively.
The diluted primer composition S1 and the printing ink R1 are printed on the PE surface of the first base material in this order using a gravure two-color printing machine equipped with a gravure plate, dried at 50 ° C., and the first A packaging material L23 having the composition of the base material layer (PE / adhesive layer / PE) / primer layer / printing layer of No. 1 was obtained.

[Examples 24 to 25] (Packaging materials L24 to L25)
Packaging materials L24 to L25 were obtained by the same method as the packaging material L23 except that the materials shown in Table 4 were used.

[Example 26] (Packaging material L26)
The primer composition S1 and the printing ink R1 were each diluted with a mixed solvent of EA / IPA (mass ratio 70/30) at Zahn cup # 3 at 25 ° C. for 15 seconds.
The primer composition S1 and the printing ink R1 were printed on an OPP film having a thickness of 20 μm in this order using a gravure two-color printing machine equipped with a gravure plate, dried at 50 ° C., and the first substrate layer. A laminate having the composition of (OPP) / primer layer / printing layer was obtained.
Next, adhesive A (TM-340V / CAT-29B manufactured by Toyo Morton Co., Ltd.) was applied onto the printed layer of the obtained laminate using a dry laminating machine so that the coating amount after drying was 2 g / m ^2. -After drying, the packaging material is bonded to a CPP film having a thickness of 30 μm to form a first base material layer (OPP) / primer layer / printing layer / adhesive layer / second base material layer (CPP). Obtained L26.

[Examples 27 to 44, 52, 53, Comparative Examples 2 to 4] (Packaging materials L27 to L44, L52, L53, LL2 to LL4)
Packaging materials L27 to L44, L52, L53, and LL2 to LL4 were obtained by the same method as the packaging material L20 except that the materials shown in Table 3 were used. For the packaging material L43, a diluted primer composition was printed on the alumina-deposited surface of the alumina-deposited PET film having a thickness of 12 μm. In the packaging material L44, a vapor-deposited surface of a VM / CPP film having a thickness of 25 μm was bonded onto the adhesive layer.

[Example 45] (Manufacturing of packaging material L45)
The primer composition S1 and the printing ink R1 were each diluted with a mixed solvent of EA / IPA (mass ratio 70/30) at Zahn cup # 3 at 25 ° C. for 15 seconds.
The diluted primer composition S1 and printing ink R1 were printed on a PET film having a thickness of 12 μm in this order using a gravure two-color printing machine equipped with a gravure plate, dried at 50 ° C., and the first substrate was dried. A laminate having a structure of a layer (PET) / primer layer / printing layer was obtained.
Next, the adhesive A was applied onto the printed layer of the obtained laminate using a dry laminating machine so that the coating amount was 2 g / m ^2, and then an aluminum foil having a thickness of 7 μm (hereinafter referred to as AL). ) And pasted together.
Next, the adhesive A is applied onto AL so that the coating amount is 2 g / m ² , and then bonded to CPP to form a first base material layer (PET) / primer layer / printed layer /. A packaging material L45 having an adhesive layer / second base material layer (AL / adhesive layer / CPP) was obtained.

[Example 46] (Packaging material L46) A packaging material L46 was obtained by the same method as the packaging material L45 except that the materials shown in Table 4 were used.

[Comparative Example 1] (Packaging material LL1)
The printing ink R1 was diluted with a mixed solvent of EA / IPA (mass ratio 70/30) using Zahn cup # 3 at 25 ° C. for 15 seconds. Diluted printing ink R1 is printed on a PET film having a thickness of 12 μm using a gravure one-color printing machine equipped with a gravure plate, dried at 50 ° C., and the first substrate layer (PET) 1 /. A packaging material LL1 which is a constitution of a printing layer was obtained.

<Evaluation of packaging materials>
The following evaluation was performed on the obtained packaging material. The results are shown in Table 4.

(Evaluation of image quality of print layer)
The reflection density value at the 100% gradation point was measured using X-Rite 530. Based on the measured values, the image quality was evaluated according to the following criteria. A, B and C are ranges in which there is no practical problem.
A (excellent): Reflection density value is 2.1 or more B (good): Reflection density value is 1.7 or more and less than 2.1 C (possible): Reflection density value is 1.5 or more and 1.7 Less than D (impossible): Reflection density value is less than 1.5

(Desorption speed)
The obtained packaging material is cut into a size of 1.5 cm × 1.5 cm, immersed in 50 g of an aqueous solution having a solid content concentration of sodium hydroxide (hereinafter, NaOH) of 3%, and then stirred at a liquid temperature of 60 ° C. and a rotation speed of 150 rpm. bottom. The detachability of the first base material was visually observed and evaluated according to the following criteria. A, B and C are ranges in which there is no practical problem.
A (excellent): All the printing layers are peeled off from the first base material within 30 minutes of stirring, and the first base material is detached. B (good): The printing layer exceeds 30 minutes of stirring and within 2 hours. Is all peeled off from the first base material and the first base material is desorbed. D (impossible): Other than A to C

(Dirt on the base material after desorption)
The obtained packaging material was cut into a size of 1.5 cm × 1.5 cm, immersed in 50 g of an aqueous solution having a solid content of sodium hydroxide of 3%, and then stirred at a liquid temperature of 60 ° C. and a rotation speed of 150 rpm. The printed layer on the first substrate after stirring for 2 hours was visually observed and evaluated according to the following criteria. A, B and C are ranges in which there is no practical problem.
A (excellent): 90% or more of the surface area of the first substrate has the printed layer removed. B (good): 80% or more and less than 90% of the surface area of the first substrate is the printed layer. C (possible): 70% or more and less than 80% of the surface area of the first substrate has the print layer removed D (impossible): Other than A to C

(Yield of transparent substrate)
The packaging materials L1, L26, and L47 to L53 were evaluated for desorption suitability under more severe conditions. 100 samples of packaging materials L1, L26, L47 to L53 cut into a size of 1.5 cm × 1.5 cm and 800 g of a 3% aqueous solution of sodium hydroxide (hereinafter referred to as NaOH) in a 1 L flask were placed in a 1 L flask. The mixture was stirred at ° C. and a rotation speed of 200 rpm for 45 minutes. After washing and drying the sample with water, a transparent film from which the print layer was visually removed by 80% or more was collected and the number of sheets was counted. The yield was calculated by the following formula. The results are shown in Table 4 (continued).
Yield = number of transparent films recovered / number of plastic base materials constituting the original packaging material The yield was evaluated according to the following criteria.
A: Yield is 90% or more B: Yield is 75% or more and less than 90% C: Yield is less than 75%

The abbreviations in Table 4 are shown below.
OPP: Stretched polypropylene film Thickness 20 μm
PET: Polyethylene terephthalate film Thickness 12 μm
s-PET: Polyethylene terephthalate film for shrink thickness 30 μm
VM / OPP: Stretched polypropylene film with a vapor-deposited layer of aluminum deposited in an amorphous form, thickness 50 μm
PE: Linear low density polyethylene film Thickness 50 μm
CPP: Unstretched polypropylene film Thickness 30 μm
Alumina / PET: Alumina vapor-deposited PET film Thickness 12 μm
VM / CPP: Unstretched polypropylene film with a vapor-deposited layer of aluminum deposited in an amorphous shape 25 μm thick
AL: Aluminum foil thickness 7 μm
NY: Nylon film thickness 15 μm
Anti-fog OPP: Futamura Chemical Co., Ltd. Stretched polypropylene film Anti-fog grade AF642 (thickness 20 μm)

From the evaluation results, the packaging material of the present invention not only has excellent detachability of the printing base material in the packaging material having the printing layer on the outside, but also removes the printing base material in the packaging material having the printing layer inside the laminate. It is also excellent in releasability. Further, the packaging material of the present invention has good image quality of the printing layer.
Therefore, the packaging material of the present invention and the packaging container using the packaging material are useful as the packaging material and the packaging container suitable for plastic recycling.

Claims (7)

A packaging material provided with at least a first base material, a primer layer for desorbing the first base material, and a printing layer in this order.
The primer layer contains a cured product of a hydroxyl group-containing resin and polyisocyanate, and contains
The primer layer is provided in contact with the first base material, and the primer layer is provided .
The hydroxyl group-containing resin is a urethane resin having an acid value of 15 to 70 mgKOH / g.
The urethane resin contains a structural unit derived from at least one polyol selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols.
A packaging material in which the polyol contains 50% by mass or more of a polyester polyol having an ester bond concentration of 4 to 11 mmol / g. A packaging material provided with at least a first base material, a primer layer for desorbing the first base material, a printing layer, and a second base material in this order.
The primer layer contains a cured product of a hydroxyl group-containing resin and polyisocyanate, and contains
The primer layer is provided in contact with the first base material, and the primer layer is provided .
The hydroxyl group-containing resin is a urethane resin having an acid value of 15 to 70 mgKOH / g.
The urethane resin contains a structural unit derived from at least one polyol selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols.
A packaging material in which the polyol contains 50% by mass or more of a polyester polyol having an ester bond concentration of 4 to 11 mmol / g.
The packaging material according to claim 1 or 2 , wherein the urethane resin has a molecular weight distribution (Mw / Mn) of 6.0 or less. Any one of claims 1 to 3 , wherein the primer layer further contains at least one resin selected from the group consisting of a cellulose resin, a vinyl chloride resin, a rosin resin, an acrylic resin and a styrene-maleic acid copolymer resin. The packaging material described in the section. The packaging material according to any one of claims 1 to 4 , wherein the primer layer further contains an extender pigment. A packaging container in which at least a part thereof is formed of the packaging material according to any one of claims 1 to 5. A method for producing a recycled base material, which comprises a step of immersing the packaging material according to any one of claims 1 to 5 or the packaging container according to claim 6 in a basic aqueous solution.
A method for producing a recycled base material, wherein the basic aqueous solution contains 0.5 to 20% by mass of the total basic aqueous solution, and the water temperature of the basic aqueous solution at the time of immersion is 25 to 120 ° C.