JP2021088184A - Packaging material and package - Google Patents

Abstract

To provide a packaging material that has excellent adhesive strength and boil-retort resistance, and is excellent in the separation or desorption of a sealant base material from the packaging material, and a package formed from the packaging material.SOLUTION: A packaging material has a structure in which at least a first base material, a printed layer, a polyurethane adhesive layer for the detachment of a second base material, and the second base material are laminated from the outer layer side in the stated order, the polyurethane adhesive layer being provided in contact with the second base material. A package is formed from the packaging material.SELECTED DRAWING: None

Description

The present invention relates to a packaging material suitable for recyclability of a plastic base material and a packaging container formed of the packaging 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. A printing layer is applied to these plastic base materials with gravure ink, flexographic ink, and other printing inks, and the plastic base material is further bonded to the sealant base material via an adhesive or the like to form a laminated body, and then the laminated body is cut. Then, it is 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, Cited Document 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. Further, Patent Document 2 discloses a technique of printing an ink using a polyurethane resin or an acrylic resin having an acidic group as a binder resin and removing the printing layer with alkaline water. However, these are techniques that only remove the front printing ink on the outside of the package, and have not yet peeled off the sealant base material and other base materials in the laminated laminate.

The base material including the plastic layer and the printing layer and the sealant base material peel off the sealant base material and other base materials from the packaging material laminated with an adhesive, and are particularly thick and occupy the entire packaging material. The technology for recycling a high proportion of sealant base materials will be an important technology that can be used industrially in order to promote the recycling of plastics and contribute to environmental conservation. However, a packaging material having an adhesive layer that has both the required performance required as a laminate adhesive and the function of peeling the sealant base material from other base materials has not yet been reported.

Japanese Unexamined Patent Publication No. 2001-131484 Japanese Unexamined Patent Publication No. 11-209677

An object of the present invention is to provide a packaging material having excellent adhesive strength and boil / retort resistance, and excellent separation / detachment of a base material from the packaging material, and a packaging container formed of the packaging material. To do.

The present invention relates to the following inventions [1] to [8].

[1] At least, the first base material, the printing layer, the polyurethane-based adhesive layer for desorbing the second base material, and the second base material are laminated in this order from the outer layer side. A packaging material in which the polyurethane-based adhesive layer is provided in contact with the second base material.

[2] The packaging material according to [1], wherein the polyurethane-based adhesive layer is a cured product of an adhesive containing a polyol component and a polyisocyanate component, and the polyol component contains a polyester polyol.

[3] The packaging material according to [2], wherein the polyester polyol has a urethane bond.

[4] The packaging material according to [2] or [3], wherein the polyisocyanate component contains at least one selected from the group consisting of an aliphatic polyisocyanate and an aromatic aliphatic polyisocyanate.

[5] The packaging material according to any one of [1] to [4], wherein the acid value of the adhesive is 5 to 45 mgKOH / g.

[6] Any of [1] to [5], wherein the polyurethane-based adhesive layer further contains oxygen acid of phosphorus or a derivative thereof in an amount of 0.01 to 5% by mass based on the mass of the polyurethane-based adhesive layer. The packaging material according to item 1.

[7] The packaging material according to any one of [1] to [6], wherein the polyurethane-based adhesive layer further contains fine particles having an average particle size of 1 to 10 μm.

[8] The packaging material according to [7], wherein the content of the fine particles is 0.1 to 10% by mass based on the mass of the polyurethane-based adhesive layer.

[9] The packaging material according to any one of [1] to [8], wherein the polyurethane-based adhesive layer has a thickness of 1 to 6 μm.

[10] The packaging material according to any one of [1] to [9], wherein the second base material contains polyolefin.

[11] Any one of [1] to [10], wherein the second base material is a layer laminated by extrusion lamination, and the thickness of the polyurethane-based adhesive layer is 0.01 to 1 μm. The packaging material described in the section.

[12] A packaging container in which at least a part thereof is formed of the packaging material according to any one of [1] to [10].

INDUSTRIAL APPLICABILITY The present invention provides a packaging material having excellent adhesive strength and boil / retort resistance, and excellent separation / detachment of a base material from a packaging material, and a packaging container formed of the packaging material. Can be done.

The packaging material of the present invention has at least a first base material, a printing layer, a polyurethane-based adhesive layer for desorbing a second base material (hereinafter, also referred to as a desorbable adhesive layer), and a second base material. It is a packaging material having a structure in which the base materials are laminated from the outer layer side in this order, and is characterized in that the polyurethane-based adhesive layer is provided in contact with the second base material.
In the packaging material, the second base material can be separated and recovered by removing the polyurethane-based adhesive layer for removing the second base material from the second base material. Therefore, the packaging material of the present invention corresponds to the packaging material used for separating and recovering the second base material.
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.

<Polyurethane-based adhesive layer for desorbing the second base material>
"Desorption" in the polyurethane-based adhesive layer for desorbing the second base material means that the adhesive layer is neutralized with a basic aqueous solution and dissolved or swollen, so that the printed layer and the second group are desorbed. It means that the material is peeled off. When (1) the polyurethane adhesive layer is melted and the printed layer and the second base material are peeled off, (2) the polyurethane adhesive layer is melted and swollen, etc. Includes both forms when the adhesive layer is detached from the second substrate.
Since the present invention aims to obtain the second base material as a recycled base material / recycled base material, it is preferable to remove as much polyurethane-based adhesive layer as possible from the second base material. .. Specifically, it is preferable that at least 50% by mass or more of the 100% by mass of the polyurethane-based adhesive 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 from the group consisting of sodium hydroxide and potassium hydroxide.

As a mechanism of desorption, in a packaging material containing a polyurethane-based adhesive layer (for example, a first base material / printing layer / polyurethane-based adhesive layer / second base material, etc.), a base is formed from a gap between the layers. It is presumed that the acidic aqueous solution permeates and comes into contact with the polyurethane-based adhesive layer, and the base material 2 is detached by dissolution of the polyurethane-based adhesive layer or the like. Therefore, it is preferable that the desorption step is performed in a state where the packaging material is cut and the cross section is exposed, that is, in a state where the polyurethane adhesive layer is exposed.

The polyurethane-based adhesive layer in the present invention is in contact with the second base material described later, the second base material is removed, the second base material is separated and recovered from the packaging material, and the recycled base material is recycled. Since the solder resist, the color resist, etc. are provided for the purpose of obtaining, not only the technical fields are completely different, but also a certain amount of the film is left after the treatment with the alkaline aqueous solution. Therefore, the polyurethane type of the present invention is used. The technical idea is different from the adhesive layer.

<Adhesive for forming polyurethane adhesive layer>
The polyurethane-based adhesive layer is not particularly limited as long as it is polyurethane-based, and is preferably a cured product of a two-component curable polyurethane-based adhesive containing a polyol component and a polyisocyanate component.

[Polycarbonate component]
The polyol component is not particularly limited and can be selected from conventionally known polyol components, and may be used alone or in combination of two or more.
The polyol component preferably contains a polyester polyol because the desorption property is improved when it has an ester bond having a high affinity with an alkaline aqueous solution.
Polyester polyols include, but are not limited to, for example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, tetrahydrophthalic anhydride, Dibasic acids such as hexahydrophthalic anhydride, maleic anhydride, and itaconic anhydride, dialkyl esters thereof, or mixtures thereof (hereinafter, also referred to as carboxyl group components),
For example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, butylene glycol, neopentyl glycol, dineopentyl glycol, trimethylolpropane, glycerin, 1,6-hexanediol, 1,4-butanediol, 1,4-Cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 3,3'-dimethylol heptane, 1,9-nonanediol, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol , Polyether polyols, polycarbonate polyols, polyolefin polyols, acrylic polyols, polyurethane polyols and other diols or mixtures thereof (hereinafter, also referred to as hydroxyl group components).
Examples thereof include polyester polyols obtained by reacting the above; or polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly (β-methyl-γ-valerolactone).
Two or more kinds of the above-mentioned carboxyl group component and hydroxyl group component may be used in combination.

The polyester polyol preferably has a urethane bond, and may be a polyester polyurethane polyol obtained by reacting with diisocyanate. Further, the polyester polyol and the polyester polyurethane polyol may be those obtained by further reacting with an acid anhydride.
Examples of the diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalenedi isocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate and the like. Can be mentioned.
Examples of the acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, trimellitic acid ester anhydride and the like. Examples of the trimellitic acid ester anhydride include ethylene glycol bisamhydrotrimerite and propylene glycol bisuanhydrotrimeritate.

Above all, the polyester polyol preferably contains an acid anhydride modified product of the polyester polyurethane polyol. Since the polyester polyol component has a urethane bond, excellent heat resistance and adhesiveness can be exhibited. When the polyester polyol is an acid anhydride modified product, the acid value can be finely controlled, and a polyester polyol in a suitable acid value range as described later can be easily obtained, which is preferable.

The adhesive for forming the polyurethane-based adhesive layer preferably has an acid value. When the adhesive has an acid value, the neutralizing action with the alkali facilitates the peeling of the second base material in the basic aqueous solution. Therefore, the polyester polyol preferably has an acid value, and the acid value of the polyester polyol is preferably 8 mgKOH / g or more, more preferably 10 mgKOH / g or more. The acid value of the polyester polyol is preferably 45 mgKOH / g or less. When the polyester polyol has the above acid value, the adhesive layer formed from the adhesive containing the polyester polyol exhibits excellent detachability while maintaining the adhesive strength, and is a second base material from the packaging material. It is most suitable for recycling applications.
When the polyester polyol contains a plurality of polyester polyols, the acid value of the polyester polyol can be obtained from the acid value of each polyester polyol and its mass ratio.

The polyester polyol has a number average molecular weight (Mn) of preferably 3,000 to 20,000, more preferably 5,000 to the number average molecular weight (Mn) of the polyester polyol mixture from the viewpoint of heat sterilization treatment of the adhesive layer and coatability. It is 15,000, particularly preferably 7,000 to 12,000. When the number average molecular weight (Mn) of the polyester polyol is 3,000 or more, not only coatability but also sufficient retort suitability can be exhibited, and when it is 20,000 or less, not only coatability but also desorption It is preferable because the property is improved.
The number average molecular weight of the present specification is a value converted to standard polystyrene using GPC (gel permeation chromatography) "Shodex GPC System-21" manufactured by Showa Denko KK and Tetrohydrofuran as a solvent.

The polyester polyol may be used in combination with a plurality of polyester polyols in order to satisfy various physical properties required for the packaging material, and the number average molecular weight of the polyester polyol component in that case is the number average molecular weight of each polyester polyol and its It can be obtained from the mass ratio.
Each polyester polyol component preferably contains a polyester polyol having a number average molecular weight of 5,000 to 15,000, and further contains a polyester polyol having a number average molecular weight of less than 3,000 in order to improve substrate adhesion. Is preferable.
The content of the polyester polyol having a number average molecular weight of less than 3,000 is preferably 0 to 30% by mass, preferably 0 to 20% by mass, based on the total amount of the polyester polyol components. When it is 30% by mass or less, the retort resistance does not decrease, which is preferable.

The polyester polyol can contain the following three types of polyols from the viewpoint of adhesive performance and detachability.
First polyol: Polyester polyol having an acid value of 10 mg / KOH or more Second polyol: Polyester polyol having a number average molecular weight of less than 3,000 Third polyol: Polyester polyol having a number average molecular weight of 5,000 or more (However, the second (Except when the polyol and the third polyol are the first polyol component)

The first polyol component has a role of imparting desorption. The second polyol component improves the adhesion to the base material and contributes to the improvement of coatability. The third polyol component has a role of improving the retort property.
The content of the first polyol component is preferably 50% by mass or more with respect to the total amount of the polyester polyol component from the viewpoint of exhibiting sufficient desorption. The first polyol component is preferably a polyester polyurethane polyol modified with an acid anhydride, more preferably has a number average molecular weight of 5,000 or more and 10,000 or less, and an acid value of 15 to 40 mgKOH / g. It is as follows.
The second polyol component preferably has an acid value of 5 mgKOH / g or less, more preferably 1 mgKOH / g or less.
The third polyol component is preferably a polyester polyurethane polyol modified with an acid anhydride, more preferably has a number average molecular weight of 5,000 or more and 10,000 or less, and an acid value of 5 mgKOH / g or less.

(Other polyols)
The adhesive in the present invention may contain other polyols other than the polyester polyol described above. The polyols that may be contained in addition to the polyester polyol are not particularly limited, and examples thereof include polycarbonate polyols, polycaprolactone polyols, polyether polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, and fluorine-based polyols. .. These may be used alone or in combination of two or more.

[Polyisocyanate component]
The polyisocyanate component is not particularly limited and can be selected from conventionally known polyisocyanates, and preferably contains at least one polyisocyanate component selected from the group consisting of aliphatic polyisocyanates and aromatic aliphatic polyisocyanates. These may be used alone or in combination of two or more.

(Aliphatic polyisocyanate)
The aliphatic polyisocyanate is not limited to the following, and a well-known aliphatic diisocyanate or a compound derived from an alicyclic diisocyanate can be used.
Examples of the aliphatic polyisocyanate that can be used in the present invention include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, and 1,3. -Alphatic diisocyanates such as butylene diisocyanate, 2,4,4- 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, methyl Alicyclic diisocyanates such as 2,6-cyclohexanediisocyanate, 1,4-bis (isocyanatemethyl) cyclohexane, and 1,3-bis (isocyanatemethyl) cyclohexane;
Alternatively, polyisocyanates such as allophanate type, nurate type, biuret type, adduct type derivatives, or complexes thereof derived from the above aliphatic diisocyanate or alicyclic diisocyanate; and the like can be mentioned.
The derivative is preferably a nurate type or adduct type derivative, and particularly preferably an adduct type.
The aliphatic polyisocyanate is preferably a polyisocyanate derived from hexamethylene diisocyanate (hereinafter referred to as HDI), which makes it easy to secure a balance between desorption and laminated physical properties.

(Aromatic aliphatic polyisocyanate)
The aromatic aliphatic polyisocyanate is not limited to the following, and a compound derived from a well-known aromatic aliphatic diisocyanate can be used.
Examples of the aromatic aliphatic polyisocyanate that can be used in the present invention include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,3- or 1 , 4-bis (1-isocyanate-1-methylethyl) benzene or a mixture thereof, etc. Arophilic aliphatic diisocyanate;
Alternatively, a polyisocyanate such as a derivative of the above aromatic aliphatic diisocyanate or a complex thereof; and the like can be mentioned.

(Other polyisocyanate components)
The adhesive may contain other polyisocyanates other than the above-mentioned aliphatic polyisocyanate and aromatic aliphatic polyisocyanate. Examples of other polyisocyanates include aromatic diisocyanates such as toluene diisocyanate and diphenylmethane diisocyanate; or polyisocyanates such as derivatives of the above diisocyanates or complexes thereof.
The derivative is preferably an adduct type derivative.

<Manufacturing of adhesive>
The adhesive for forming the polyurethane-based adhesive layer may further contain other components. Other components may be added to either the polyol component or the polyisocyanate component, or may be added when the polyol component and the polyisocyanate component are mixed.

[Other ingredients]
(Silane coupling agent)
The adhesive can further contain a silane coupling agent in order to increase heat resistance and water resistance. Examples of the silane coupling agent include trialkoxysilanes having a vinyl group such as vinyltrimethoxysilane and vinyltriethoxysilane, 3-aminopropyltriethoxysilane, and N- (2-aminoethyl) 3-aminopropyltrimethoxysilane. It has a glycidyl group such as trialkoxysilane having an amino group such as 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane. Examples thereof include trialkoxysilane. The amount of the silane coupling agent added is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, based on the solid content of the adhesive.

(Oxygen acid of phosphorus or its derivative)
The adhesive may further contain an oxygen acid of phosphorus or a derivative thereof in order to enhance acid resistance. Among the oxygen acids of phosphorus or derivatives thereof, the oxygen acid of phosphorus may be any one having at least one free oxygen acid, for example, hypophosphoric acid, phosphoric acid, orthophosphoric acid, the following. Examples thereof include phosphoric acids such as phosphoric acid, and condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and ultraphosphoric acid. Examples of the derivative of the oxygen acid of phosphorus include those in which the oxygen acid of phosphorus is partially esterified with alcohols while leaving at least one free oxygen acid. Examples of these alcohols include fatty alcohols such as methanol, ethanol, ethylene glycol and glycerin, and aromatic alcohols such as phenol, xylenol, hydroquinone, catechol and fluoroglycinol. The oxygen acid of phosphorus or a derivative thereof may be used in combination of two or more. The amount of phosphorus oxygen acid or a derivative thereof added is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, based on the solid content of the adhesive, and is 0.1. It is particularly preferably ~ 1% by mass.

In addition, the adhesive may contain the above-mentioned oxygen acid of phosphorus or a derivative thereof in order to improve the detachability of the second base material and enhance the recyclability of the second base material. From the viewpoint of the strength and detachability of the packaging material, the content of the oxygen acid of phosphorus or a derivative thereof is preferably 0.01 to 5% by mass based on the solid content of the adhesive. That is, the polyurethane-based adhesive layer contains an oxygen acid of phosphorus or a derivative thereof in a range of preferably 0.01 to 5% by mass based on the mass of the polyurethane-based adhesive layer.
More specifically, the blending amount of the oxygen acid of phosphorus is more preferably 0.01 to 1% by mass, still more preferably 0.01 to 0.5% by mass, based on the solid content of the adhesive. When the blending amount is 0.01% by mass or more, the detachability is further improved while maintaining the strength of the packaging material. When it is within 1% by mass, the strength as a packaging material is more excellent.
The blending amount of the phosphoric acid derivative is preferably 0.01 to 5% by mass, more preferably 0.1 to 3% by mass, based on the solid content of the adhesive. When the blending amount is 0.01% by mass or more, the detachability is further improved while maintaining the strength of the packaging material. When it is within 5% by mass, the strength as a packaging material is more excellent.

(Leveling agent or antifoaming agent)
The adhesive may further contain a leveling agent or defoaming agent to improve the appearance of the laminate. Leveling agents include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, polyether ester-modified hydroxyl group-containing polydimethylsiloxane, acrylic copolymer, and methacryl. Examples thereof include system copolymers, polyether-modified polymethylalkylsiloxanes, acrylic acid alkyl ester copolymers, methacrylic acid alkyl ester copolymers, and lecithin.
Examples of the defoaming agent include known ones such as a silicone resin, a silicone solution, and a copolymer of an alkyl vinyl ether, an acrylic acid alkyl ester, and a methacrylic acid alkyl ester.

(Reaction Accelerator) Since the adhesive accelerates the urethanization reaction, it can further contain a reaction accelerator. As the reaction accelerator, metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimarate; 1,8-diazabicyclo (5,4,0) undecene-7,1,5-diazabicyclo (4,3,0) Tertiary amines such as nonen-5,6-dibutylamino-1,8-diazabicyclo (5,4,0) undecene-7; reactive tertiary amines such as triethanolamine One or more reaction promoters selected from these groups can be used.

The adhesive may contain various additives as long as the effects of the present invention are not impaired. Examples of the additive include inorganic fillers such as silica, alumina, mica, talc, aluminum flakes, and glass flakes, layered inorganic compounds, stabilizers (antioxidants, heat stabilizers, ultraviolet absorbers, hydrolysis inhibitors, etc.). ), Anticorrosive agents, thickeners, plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, fillers, crystal nucleating agents, catalysts for adjusting the curing reaction, and the like.

Further, the adhesive can contain fine particles having an average particle size of 1 to 10 μm as the above-mentioned additive in order to improve the detachability and the recyclability of the second base material. It is presumed that the inclusion of such fine particles improves the detachability because the contact area between the adhesive and the base material is reduced while the strength of the packaging material is maintained by the anchoring effect on the base material.
When the average particle size is 1 μm or more, the detachability is further improved while maintaining the strength of the packaging material. When the average particle size is within 10 μm, the strength as a packaging material can be maintained. The average particle diameter in the present specification means the median diameter when measured by a particle diameter distribution measuring device using a laser diffraction / scattering method.
The fine particles having an average particle diameter of 1 to 10 μm are not particularly limited, and are, for example, inorganic fillers such as silica, alumina, mica, talc, aluminum flakes, and glass flakes, as well as aluminum hydroxide and precipitated barium sulfate. , Magnesium carbonate, calcium carbonate, zeolite, and resin beads such as acrylic beads and urethane beads.

From the viewpoint of the strength and detachability of the packaging material, the blending amount of the fine particles is preferably 0.1 to 10% by mass, more preferably 0.5 to 5.0, based on the solid content of the adhesive. It is mass%. That is, the polyurethane-based adhesive layer in the present invention contains fine particles having an average particle diameter of 1 to 10 μm in a range of preferably 0.1 to 10% by mass based on the mass of the polyurethane-based adhesive layer. Yes, more preferably in the range of 0.5 to 5.0% by mass.
When the content is 0.5% by mass or more, the strength of the packaging material is maintained and the detachability is further improved. When it is within 5.0% by mass, the strength as a packaging material is more excellent.

The polyurethane-based adhesive layer preferably contains both the oxygen acid of phosphorus or a derivative thereof and the fine particles having an average particle size of 1 to 10 μm. By including both, the detachability and the removal rate are further improved.

When the viscosity of the adhesive is room temperature to 150 ° C., preferably room temperature to 100 ° C. and 100 to 10,000 mPa · s, preferably 100 to 5,000 mPa · s, the adhesive can be used in a solvent-free type. If the viscosity of the adhesive is higher than the above range, it may be diluted with an organic solvent. As the organic solvent, for example, an ester type such as ethyl acetate, a ketone type such as methyl ethyl ketone, an aromatic hydrocarbon type such as toluene and xylene, etc., which are inert to the polyisocyanate component, are preferably used and are appropriately selected. Can be used.

The acid value immediately after blending the adhesive for forming the polyurethane-based adhesive layer for desorbing the second base material is preferably 5 mgKOH / g or more, more preferably 7 mgKOH / g or more, still more preferably. It is 10 mgKOH / g or more, particularly preferably 20 mgKOH / g or more. The acid value immediately after blending the adhesive is preferably 45 mgKOH / g or less, more preferably 40 mgKOH / g or less, and further preferably 35 mgKOH / g or less.
When the acid value is 5 mgKOH / g or more, the peeling of the second base material with a basic aqueous solution becomes easy. When the acid value is 45 mgKOH / g or less, the adhesiveness and water resistance of the adhesive layer are good. Therefore, when the acid value is within the above range, it is preferable because the sealant base material can be recovered by exhibiting excellent desorption while maintaining the adhesive strength and retort resistance required for the laminated adhesive.

When the polyol component and the polyisocyanate component are blended, the equivalent ratio (NCO / OH) of the isocyanate group of the polyisocyanate to the hydroxyl group in the polyol is 0.3 to 5.0. It is more preferably 0.3 to 2.0, and particularly preferably 0.5 to 1.5.

As a method for forming a polyurethane-based adhesive layer, generally, a printed layer is formed on a first base material, the adhesive is applied on the printed layer, and if necessary, an organic step is performed. Examples thereof include a method in which the solvent is volatilized, then bonded to a second base material using a laminator, and cured at room temperature or heating to form a polyurethane-based adhesive layer.
When the second base material is a base material made of a sealant resin, the second base material may be a layer laminated by extrusion lamination. As a method of laminating the second base material by extrusion lamination, for example, an adhesive is applied on the print layer of a laminate having a print layer on the first base material, and if necessary, an organic substance is subjected to a drying step. After volatilizing the solvent, the sealant resin melted by the T-die method is extruded, the second base material is laminated with a cooling roll, and cured at room temperature or heating to form a removable adhesive layer. Can be mentioned.
The amount of the adhesive applied after drying is not limited and is usually in ^{the range of 0.001 to 6 g / m 2 , preferably 1 to 2.5 g / m 2 for} the solvent-free type and 1 to 6 g / m for the solvent type. It is in the range of ^2. The thickness of the adhesive layer is not limited and is usually in the range of 0.001 to 5 μm, preferably in the range of 1 to 2 μm in the solvent-free type and 1 to 5 μm in the solvent type.
When the second base material is a layer laminated by extrusion lamination, the amount of the adhesive applied after drying is preferably in the range of 0.01 to 1 μm, more preferably 0.05 to 0.05. The range is 0.5 μm.

<First base material>
Examples of the first base material include plastic films generally used for packaging materials, gas barrier base materials such as metal foil, and paper.
Examples of the plastic film 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 polyolefins, polyesters, polyamides, polystyrenes, vinyl chloride resins, vinyl acetate resins, ABS resins, acrylic resins, acetal resins, polycarbonate resins, and fibrous plastics.

More specifically, polyester resin films such as polyethylene terephthalate, polyethylene naphthalate (PEN), polylactic acid (PLA); polyolefin resin films such as polyethylene (PE), polypropylene (PP); polystyrene resin films; nylon 6, Polyethylene resin film such as poly-p-xylylene adipamide (MXD6 nylon); polycarbonate resin film; polyacrylic nitrile resin film; polyimide resin film; these multilayers (eg, nylon 6 / MXD6 / nylon 6, Nylon 6 / polyethylene-vinyl alcohol copolymer / nylon 6) or a mixture; etc. 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 film having a vapor-deposited layer of aluminum, silica, alumina and the like; and the like. In the case of aluminum foil, a thickness in the range of 3 to 50 μm is preferable from the economical point of view.

<Print layer>
The printing layer is a layer for forming an arbitrary printing pattern for the purpose of decoration, imparting aesthetics, contents, expiration date, display of a manufacturer or a seller, and the like, and includes a solid printing layer. The printing layer can be provided, for example, between the base material and the adhesive layer, and may be provided on the entire surface or a part of the base material.
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 10 μm or less, more preferably 1 μm or more and 5 μm or less, and further preferably 1 μm or more and 3 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. Polybutylal type, cyclized rubber type, chloride rubber type, or a binder in which they are appropriately used can be used.

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.

A primer layer may be formed between the first base material and the printing layer, if necessary, in order to satisfy various required performances for the packaging material such as base material adhesion. As the primer layer, a conventionally known one can be used.

<Second base material>
The second base material includes, for example, the base material mentioned in the above-mentioned first base material or a sealant base material, and 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 polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE), acid-modified polyethylene, polypropylene (PP), acid-modified polypropylene, and copolymerization. Examples thereof include 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 preferably polyethylene such as low-density polyethylene, linear low-density polyethylene or high-density polyethylene, acid-modified polyethylene, polypropylene, acid-modified polypropylene, copolymerized polypropylene or the like.
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 laminated film having the base material 1 and the printing layer and the second base material are made of a polyurethane-based material for desorbing the second base material. A method of bonding using an adhesive; a method of melting the resin constituting the second base material, extruding it onto a polyurethane-based adhesive layer for desorbing the second base material, and cooling and solidifying it; etc. Can be mentioned.

The following is an example of the structure of the packaging material of the present invention, but the present invention is not limited thereto.
Biaxially stretched polypropylene (hereinafter OPP) / printing layer / polyurethane adhesive layer / unstretched polypropylene (hereinafter CPP),
OPP / printing layer / polyurethane adhesive layer / AL vapor deposition CPP (hereinafter referred to as VMCPP),
OPP / printing layer / polyurethane adhesive layer / PE,
Biaxially stretched nylon (hereinafter ONY) / printing layer / polyurethane adhesive layer / PE,
ONY / printing layer / polyurethane adhesive layer / CPP,
PET / printing layer / polyurethane adhesive layer / CPP,
PET / printing layer / adhesive layer / ONY / polyurethane adhesive layer / CPP,
Transparent vapor deposition PET / printing layer / adhesive layer / NY / polyurethane adhesive layer / CPP,
PET / printing layer / adhesive layer / AL / polyurethane adhesive layer / CPP,
PET / printing layer / adhesive layer / AL / polyurethane adhesive layer / PE,
PET / printing layer / adhesive layer / ONY / adhesive layer / AL / polyurethane adhesive layer / CPP,
PET / printing layer / adhesive layer / AL / adhesive layer / ONY / polyurethane adhesive layer / CPP,
PET / printing layer / polyurethane adhesive layer / LDPE ^EXT ,
ONY / Print layer / Polyurethane adhesive layer / LLDPE ^EXT ,
OPP / printing layer / polyurethane adhesive layer / LDPE ^EXT ,
OPP / printing layer / polyurethane adhesive layer / LLDPE ^EXT ,
PET / printing layer / adhesive layer / AL / polyurethane adhesive layer / LDPE ^EXT ,
PET / printing layer / adhesive layer / AL / polyurethane adhesive layer / LLDPE ^EXT

<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 sealant 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>
In the method for producing a recycled base material in the present invention, the first base material, the printing layer, the polyurethane adhesive layer for desorbing the second base material, and the second base material are laminated in this order from the outer layer side. The step of immersing the packaging material having the above-mentioned structure in a basic aqueous solution is included. More specifically, the method for producing a recycled base material in the present invention includes a step of immersing the packaging material in a basic aqueous solution and a step of peeling and recovering the second base material from the packaging material.

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 maintain sufficient basicity to dissolve or swell the polyurethane-based adhesive layer and peel off the second base material.
The basic aqueous solution permeates from the end portion of the packaging material, contacts the polyurethane-based adhesive layer, dissolves or swells, and separates the printed layer from the second base material. Therefore, in order to efficiently proceed with the desorption step, it is preferable that the packaging material is cut or crushed and the polyurethane adhesive layer is exposed on the cross section when immersed in the basic aqueous solution. In such a case, the print layer, the base material, and the like can be removed 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 particularly 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 after the printing layer is peeled off from the packaging material to recover the second base material, and then the second base material is washed with water and dried. The removal rate of the polyurethane-based adhesive layer on the surface of the second base material is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more.

Therefore, in the present invention, a step of immersing the packaging material in a basic aqueous solution, a step of peeling off the printing layer to remove the second base material, a step of separating and recovering the second base material, and a second base material. The recycled base material of the second base material can be obtained through the steps of washing with water and drying. 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 more detail with reference to Examples and Comparative Examples. “Parts” and “%” in Examples and Comparative Examples mean “parts by mass” and “% by mass” unless otherwise specified.

<Measurement of acid value>
Precisely weigh about 1 g of the sample in an Erlenmeyer flask with a stopper, add 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixture to dissolve it, add a phenolphthalein test solution as an indicator, and add it for 30 seconds. Retained. Then, the solution was titrated with a 0.1 N alcoholic potassium hydroxide solution until the solution turned pink, and the acid value was determined by the following formula.
Acid value (mgKOH / g) = (5.611 × a × F) / S
S: Sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Factor of 0.1N alcoholic potassium hydroxide solution

<Number average molecular weight (Mn)>
The number average molecular weight (Mn) was measured using GPC (gel permeation chromatography) "Shodex GPC System-21" manufactured by Showa Denko KK. In the measurement, tetrohydrofuran was used as a solvent, and the value converted to standard polystyrene was obtained.

<Manufacturing of aqueous primer>
The aqueous primer composition S15 described in JP-A-2017-114930 was used as an aqueous primer.
Specifically, while introducing nitrogen gas in a reactor equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube, poly (3-methyl-1,5-) having a number average molecular weight of 2,000 is introduced. 100 parts of pentaneadipate diol (hereinafter "PMPA"), 40 parts of poly (3-methyl-1,5-pentaneadipate) diol with a number average molecular weight of 1,000, polyethylene glycol having a number average molecular weight of 2,000 (hereinafter "PEG") ”) 35 parts, 30 parts of 2,2-dimethylol propionic acid (hereinafter“ DMPA ”) and 109.6 parts of isophorone diisocyanate (hereinafter“ IPDI ”), 6 in 77.4 parts of methyl ethyl ketone (hereinafter“ MEK ”). A solvent solution of the terminal isocyanate prepolymer was obtained by refluxing the reaction at 80 ° C. for an hour to obtain a terminal isocyanate prepolymer and then cooling to 40 ° C.
Next, 14 parts of isophorone diamine (hereinafter "IPDA"), 8.6 parts of 2-hydroxyethylethylenediamine (hereinafter "AEA"), 1.0 part of dibutylamine (hereinafter "DBA") and 699.9 parts of acetone are mixed. The obtained terminal isocyanate prepolymer solution was gradually added to the solution at room temperature and reacted at 80 ° C. for 1 hour to obtain a solvent-type polyurethane resin solution.
Next, 13.6 parts of 28% ammonia water and 777.3 parts of ion-exchanged water were gradually added to the solvent-type polyurethane resin solution to neutralize the mixture to make it water-soluble, and further, the total amount of MEK and acetone under azeotrope. Was distilled off, and water was added to adjust the solid content to obtain a polyurethane resin having an acid value of 37.7 mgKOH / g, a solid content concentration of 30%, and a mass average molecular weight of 30,000.
65 parts of the obtained polyurethane resin, 2 parts of a styrene maleic acid resin derivative (“SMA1440H” manufactured by Sartmer, 30% solid content aqueous solution, ammonia neutralized product of alcohol-modified styrene maleic acid), vinyl chloride emulsion ( Nisshin Kagaku Kogyo Co., Ltd. "Viniblanc 700", 30% solid content aqueous solution, 4 parts of vinyl chloride and other double-binding monomer copolymer), 24 parts of water, isopropanol (hereinafter "IPA") Five parts were mixed and stirred with a disper for 30 minutes to obtain an aqueous primer.

<Manufacturing of polyol>
(Production Example 1) Polyester polyol (P-1)
830 parts of diethylene glycol and 870 parts of adipic acid are charged in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a nitrogen gas introduction pipe, and the temperature is raised to 240 ° C. while stirring under a nitrogen stream to esterify. The chemical reaction was carried out. After distilling out a predetermined amount of water and continuing the reaction until the acid value became 5 or less, the pressure was gradually reduced and the deglycolation reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. Then, the mixture was diluted with ethyl acetate until the non-volatile content became 50% to obtain a solution of a polyester polyol (P-1) having a number average molecular weight of 2,300 and an acid value of 0.7 mgKOH / g.

(Production Example 2) Polyester polyol (P-2)
Ethylene glycol 279 parts, neopentyl glycol 242 parts, 1,6-hexanediol 189 parts, terephthalic acid 81 parts, isophthalic acid in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping tank and nitrogen gas introduction tube. 710 parts of acid and 218 parts of adipic acid were charged, and the temperature was raised to 250 ° C. with stirring under a nitrogen stream to carry out an esterification reaction. After distilling out a predetermined amount of water and continuing the reaction until the acid value became 5 or less, the pressure was gradually reduced and the deglycolation reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. Then, 2 parts of isophorone diisocyanate was gradually added, and the reaction was carried out at 150 ° C. for about 2 hours to obtain a polyester polyurethane polyol. 2.5 parts of trimellitic anhydride was added to 100 parts of this polyester polyurethane polyol, reacted at 180 ° C. for about 2 hours, and then diluted with ethyl acetate until the non-volatile content became 50%, so that the number average molecular weight was 6,000. , A solution of a partially acid-modified polyester polyol (P-2) having an acid value of 14.6 mgKOH / g was obtained.

(Production Example 3) Polyester polyol (P-3)
142 parts of ethylene glycol, 156 parts of diethylene glycol, 148 parts of neopentyl glycol, 350 parts of 1,6-hexanediol, terephthalic acid in a reaction vessel equipped with a stirrer, a thermometer, a reflux cooling tube, a dropping tank and a nitrogen gas introduction tube. 437 parts, 437 parts of isophthalic acid, and 192 parts of adipic acid were charged, and the temperature was raised to 250 ° C. with stirring under a nitrogen stream to carry out an esterification reaction. After distilling out a predetermined amount of water and continuing the reaction until the acid value became 5 or less, the pressure was gradually reduced and the deglycolation reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. By adding 0.5 part of trimellitic anhydride to 100 parts of this polyester polyol, reacting at 180 ° C. for about 2 hours, and then diluting with ethyl acetate until the non-volatile content becomes 50%, the number average molecular weight is 7,500. A solution of a partially acid-modified polyester polyol (P-3) having an acid value of 3.1 mgKOH / g was obtained.

(Production Example 4) Polyester polyol (P-4)
168 parts of ethylene glycol, 312 parts of neopentyl glycol, 217 parts of 1,6-hexanediol, 89 parts of terephthalic acid, isophthalic acid in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a nitrogen gas introduction pipe. 568 parts of acid and 345 parts of sebacic acid were charged, and the temperature was raised to 250 ° C. with stirring under a nitrogen stream to carry out an esterification reaction. After distilling out a predetermined amount of water and continuing the reaction until the acid value became 5 or less, the pressure was gradually reduced and the deglycolation reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. Then, 20 parts of isophorone diisocyanate was gradually added, and the reaction was carried out at 150 ° C. for about 2 hours to obtain a polyester polyurethane polyol. To 100 parts of this polyester polyurethane polyol, 3.0 parts of ethylene glycol bisuanhydrotrimeritate was added, reacted at 180 ° C. for about 2 hours, and then diluted with ethyl acetate until the non-volatile content became 50%. A solution of a partially acid-modified polyester polyol (P-4) having a molecular weight of 8,000 and an acid value of 8.5 mgKOH / g was obtained.

(Production Example 5) Polyester polyol (P-5)
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping tank and nitrogen gas introduction tube, 124 parts of ethylene glycol, 212 parts of neopentyl glycol, 368 parts of 1,6-hexanediol, 645 parts of isophthalic acid, and adipic acid. 36 parts of acid and 265 parts of sebacic acid were charged, and the temperature was raised to 250 ° C. with stirring under a nitrogen stream to carry out an esterification reaction. After distilling out a predetermined amount of water and continuing the reaction until the acid value became 5 or less, the pressure was gradually reduced and the deglycolation reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. Then, 35 parts of isophorone diisocyanate was gradually added, and the reaction was carried out at 150 ° C. for about 2 hours to obtain a polyester polyurethane polyol. To 100 parts of this polyester polyurethane polyol, 12.0 parts of ethylene glycol bisamhydrotrimeritate was added, reacted at 180 ° C. for about 2 hours, and then diluted with ethyl acetate until the non-volatile content became 50%. A solution of a partially acid-modified polyester polyol (P-5) having a molecular weight of 9,000 and an acid value of 30.3 mgKOH / g was obtained.

(Production Example 6) Polyester polyol (P-6)
58 parts of ethylene glycol, 412 parts of diethylene glycol, 343 parts of neopentyl glycol, 517 parts of isophthalic acid, and 393 parts of adipic acid are charged in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a nitrogen gas introduction pipe. The temperature was raised to 250 ° C. with stirring under a nitrogen stream to carry out an esterification reaction. After distilling out a predetermined amount of water and continuing the reaction until the acid value became 5 or less, the pressure was gradually reduced and the deglycolation reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. 4.0 parts of trimellitic anhydride was added to 100 parts of this polyester polyol, reacted at 180 ° C. for about 2 hours, and then diluted with ethyl acetate until the non-volatile content became 50%. A solution of a partially acid-modified polyester polyol (P-6) having an acid value of 23.5 mgKOH / g was obtained.

(Production Example 7) Polyether polyol (P-7)
P-2000 (trade name, bifunctional polyoxypropylene glycol manufactured by ADEKA Co., Ltd., hydroxyl value 56.1) was placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux cooling tube, a dropping tank and a nitrogen gas introduction tube. 57 parts, P-400 (trade name, manufactured by ADEKA Co., Ltd., bifunctional polyoxypropylene glycol, hydroxyl value 265.9), 247 parts, T-400 (trade name, manufactured by Mitsui Chemicals Co., Ltd., trifunctional polyoxypropylene) 57 parts of glycol, hydroxyl value 404), 12 parts of dimethylolpropionic acid, 207 parts of ethyl acetate, 118 parts of tolylene diisocyanate, 0.102 parts of dibutyltin laurate were charged, and the temperature was raised to 90 ° C. for infrared absorption. The reaction was carried out until the peak of the isocyanate group disappeared in the spectrum. Then, it was diluted with ethyl acetate so as to have a non-volatile content of 50% to obtain a solution of a partially acid-modified polyether polyol (P-7) having a number average molecular weight of 8,500 and an acid value of 10.2 mgKOH / g.

<Adjustment of polyisocyanate>
(Production Example 8) Polyisocyanate (C-1)
Coronate 2785 (biuret-type polyisocyanate derived from hexamethylene diisocyanate, manufactured by Tosoh Corporation) is diluted with ethyl acetate to adjust the non-volatile content to 50% and NCO% = 9.6% to obtain polyisocyanate (C-1). Solution was obtained.

(Production Example 9) Polyisocyanate (C-2)
Bestanato T1890 / 100 (neurate-type polyisocyanate derived from isophorone diisocyanate (IPDI), manufactured by Ebonic Corporation) is diluted with ethyl acetate to adjust the non-volatile content to 50% and NCO% = 8.7%, and poly. A solution of isocyanate (C-2) was obtained.

(Production Example 10) Polyisocyanate (C-3)
Takenate D-110NB (trimethylolpropane adduct-type polyisocyanate derived from xylylene diisocyanate (XDI), manufactured by Mitsui Chemicals, Inc.) is diluted with ethyl acetate to have a non-volatile content of 50% and NCO% = 7.9%. To obtain a solution of polyisocyanate (C-3).

(Production Example 11) Polyisocyanate (C-4)
Coronate L (trimethylolpropane adduct-type polyisocyanate derived from toluene diisocyanate (TDI), manufactured by Tosoh Corporation) is diluted with ethyl acetate to adjust the non-volatile content to 50% and NCO% = 8.8%. A solution of polyisocyanate (C-4) was obtained.

(Production Example 12) Polyisocyanate (C-5) Milionate MR-200 (polymeric polyisocyanate derived from diphenylmethane diisocyanate (hereinafter, MDI), manufactured by Tosoh Corporation) is diluted with ethyl acetate to obtain a non-volatile content of 50%. The NCO% was adjusted to 15.5% to obtain a solution of polyisocyanate (C-5).

<Manufacturing of adhesive>
(Adhesives 1-11)
The polyol solution and the polyisocyanate solution obtained in Production Examples 1 to 7 were blended at the ratios (mass ratios) shown in Table 2, and ethyl acetate was added to prepare an adhesive solution having a non-volatile content of 30% by mass.

(Adhesive 12-23)
The polyol solution, polyisocyanate solution, and other components obtained in Production Examples 1 to 7 above are blended in the ratio (mass ratio) shown in Table 5, and ethyl acetate is added to prepare an adhesive solution having a non-volatile content of 30% by mass. It was adjusted.

The abbreviations in Table 5 are shown below.
Phosphoric acid: 85% aqueous solution of phosphoric acid Phosphoric acid derivative: Phosphanol RL-310, Aluminum hydroxide 1: BF013 manufactured by Toho Kagaku Kogyo Co., Ltd., Nippon Light Metal Co., Ltd., average particle size 1 μm
Aluminum hydroxide 2: BX103, manufactured by Nippon Light Metal Co., Ltd., average particle size 5 μm
Aluminum hydroxide 3: BF083, manufactured by Nippon Light Metal Co., Ltd., average particle size 10 μm
Acrylic resin beads: Art Pearl J-7P, manufactured by Negami Kogyo Co., Ltd., average particle size 6 μm

<Manufacturing of packaging materials>
[Example 1] Packaging material 1
Printing ink (Rio Alpha R631 White, manufactured by Toyo Ink Co., Ltd.) is mixed with ethyl acetate / IPA solvent (mass ratio 70/30) so that the viscosity becomes 16 seconds (25 ° C, Zahn Cup No. 3). Diluted to. Diluted printing ink is printed on a corona-treated OPP film having a thickness of 20 μm at a printing speed of 50 m / min using a gravure proofing machine equipped with a solid plate having a plate depth of 35 μm, dried at 50 ° C., and OPP / A laminate of print layers was obtained. The thickness of the print layer was 1 μm.
Next, the adhesive 1 was applied onto the printed layer of the obtained laminate using a laminator to volatilize the solvent, and then the coated surface was bonded to a surface corona discharge-treated CPP film having a thickness of 25 μm. The thickness of the adhesive layer was 2 μm.
Next, the obtained laminate was kept warm at 40 ° C. for 4 days to obtain a packaging material 1 having a composition of OPP (20 μm) / printing layer (1 μm) / release adhesive layer (2 μm) / CPP (25 μm). It was.

[Examples 2 to 8, Comparative Examples 1 to 3] Packaging materials 2 to 8, 16 to 18
Packaging materials 2 to 8 and 16 to 18 were obtained in the same manner as in the packaging material 1 except that the adhesive and the printing ink were changed to the adhesives shown in Table 3.

[Examples 9 to 11] Packaging materials 9 to 11
The packaging material 9 is the same as the packaging material 1 except that the thicknesses of the first base material, the printing ink, the second base material, the desorption adhesive, and the desorption adhesive layer are changed to the contents shown in Table 3. ~ 11 was obtained.

[Example 12] Packaging material 12
Printing ink (Rio Alpha R631 White, manufactured by Toyo Ink Co., Ltd.) is mixed with ethyl acetate / IPA (mass ratio 70/30) so that the viscosity becomes 16 seconds (25 ° C, Zahn Cup No. 3). Diluted. Diluted printing ink was applied to the vapor-deposited layer side of a transparent vapor-deposited PET film (GL-ARH, thickness 12 μm, manufactured by Toppan Printing Co., Ltd.) using a gravure proof machine equipped with a solid plate with a plate depth of 35 μm, and the printing speed was 50 m / min. After printing at 50 ° C., a laminate of PET / vapor deposition layer / printing layer was obtained. The thickness of the print layer was 1 μm.
Next, the adhesive 11 was applied onto the printed layer of the obtained laminate using a laminator to volatilize the solvent, and then the coated surface was bonded to a nylon film having a thickness of 15 μm. The thickness of the adhesive layer was 3 μm.
Next, the adhesive 8 was applied to the nylon film surface of the obtained laminate using a laminator to volatilize the solvent, and then the coated surface was bonded to a surface corona discharge-treated CPP film having a thickness of 70 μm. The thickness of the desorbing adhesive layer was 3 μm.
Next, the obtained laminate was kept warm at 40 ° C. for 4 days, and PET-deposited layer (12 μm) / printed layer (1 μm) / adhesive layer (3 μm) / NY (15 μm) / desorption adhesive layer (3 μm). A packaging material having a / CPP (70 μm) configuration was obtained.

[Examples 13 and 14] Packaging materials 13, 14
Packaging materials 13 and 14 were obtained in the same manner as the packaging material 12, except that the base material and the release adhesive were changed to the contents shown in Table 3.

[Example 15] Packaging material 15
The above-mentioned aqueous primer and printing ink (Rioalpha R631 white manufactured by Toyo Ink Co., Ltd.) were each subjected to ethyl acetate / IPA mixed solvent (mass ratio 70/30) to have a viscosity of 16 seconds (25 ° C., Zahn cup No.). It was diluted to be 0.3).
After printing the diluted aqueous primer and diluted printing ink on a corona-treated OPP film with a thickness of 20 μm in this order at a printing speed of 50 m / min with a gravure proofing two-color machine equipped with a solid plate with a plate depth of 35 μm. Each unit was dried at 50 ° C. to obtain a laminate of OPP / primer layer / printing layer. The thickness of the primer layer and the printing layer was 1 μm each.
Next, the adhesive 1 was applied onto the printed layer of the obtained laminate using a laminator to volatilize the solvent, and then the coated surface was bonded to a surface corona discharge-treated LLDPE film having a thickness of 40 μm. The thickness of the desorbing adhesive layer was 3 μm.
The obtained laminate was kept warm at 40 ° C. for 4 days to obtain a packaging material having a composition of OPP / primer layer / printing layer / desorption adhesive layer / LLDPE.

[Example 16] Packaging material 19
A packaging material 19 was obtained in the same manner as the packaging material 8 except that the second base material was changed to a surface corona discharge-treated CPP film having a thickness of 30 μm.

[Examples 17 to 28] Packaging materials 20 to 31
Packaging materials 20 to 31 were obtained in the same manner as the packaging material 19 except that the adhesive was changed to the adhesive shown in Table 6.

[Example 29] Packaging material 32
Printing inks (Rio Alpha R39 Indigo, R631 White, manufactured by Toyo Ink Co., Ltd.) are each viscous for 16 seconds (25 ° C., Zahn Cup No. 3) with an ethyl acetate / IPA mixed solvent (mass ratio 70/30). ) Was diluted. Each diluted printing ink was printed on a corona-treated PET film (PET) having a thickness of 12 μm in the order of indigo and white on a gravure proofing two-color machine equipped with a solid plate having a plate depth of 35 μm. The printing speed was 50 m / min, and drying was performed at 50 ° C. in each unit to obtain a PET / printed layer laminate. The thickness of the print layer was 1 μm indigo and 1 μm in white, for a total of 2 μm.
Next, the obtained laminate was sent out from the first roll, and the adhesive 3 was applied onto the printing layer using a gravure coater to volatilize the solvent to form a removable adhesive layer having a thickness of 0.3 μm. did. ^{Next, extraction polyethylene (LDPE EXT} ) was extruded from the T-die onto the removable adhesive layer at 315 ° C., cooled with a cooling roll, and then the laminate was wound up.
The obtained laminate was kept warm at 40 ° C. for 4 days, and a packaging material 32 having a composition of PET (12 μm) / printing layer (2 μm) / detachable adhesive layer (0.3 μm) / LDPE ^{EXT (35 μm).} Got

[Examples 30 and 31] Packaging materials 33 and 34
Packaging materials 33 and 34 were obtained in the same manner as the packaging material 32 except that the adhesive was changed to the adhesive shown in Table 7.

<Evaluation of packaging materials 1 to 18>
The following evaluation was performed using the obtained packaging materials 1 to 18. The results are shown in Tables 3 and 4.

(Adhesive strength: initial)
A test piece having a size of 15 mm × 300 mm was prepared from the packaging materials 1 to 18, and the peeling speed was 30 cm / min by T-type peeling under the conditions of a temperature of 20 ° C. and a relative humidity of 65% using a tensile tester. The lamination strength (N / 15 mm) between both substrates in contact with the polyurethane-based desorbing adhesive layer was measured.

(Adhesive strength: after boiling)
A pouch having a size of 21 cm × 30 cm was prepared using the packaging material 9, and a sauce containing salad oil, ketchup, and 4.2% vinegar in a mass ratio of 1: 1: 1 was vacuum-filled as the contents. The obtained pouch was boiled at 98 ° C. for 30 minutes.
A test piece having a size of 15 mm × 300 mm was prepared from the boiled pouch, and the lamination strength (N / 15 mm) between NY and LLDPE was measured in the same manner as the initial adhesive strength.

(Adhesive strength: after retort)
Using the packaging materials 12 to 14, each pouch having a size of 21 cm × 30 cm was prepared, and a sauce containing salad oil, ketchup, and 4.2% vinegar in a mass ratio of 1: 1: 1 was used as the contents. Vacuum filled. The obtained pouch was retorted at 10 rpm at 120 ° C. for 30 minutes under a pressure of 3 MPa.
From the retort-treated pouch, a test piece having a size of 15 mm × 300 mm is prepared, and the lamination strength between NY and CPP or between the aluminum foil and CPP is the same as the initial adhesive strength. (N / 15 mm) was measured.

(Removability 1)
A test piece having a size of 3.0 cm × 3.0 cm was cut out from the packaging materials 1 to 18, and immersed and stirred in 50 g of a 2% sodium hydroxide aqueous solution at 70 ° C. at a rotation speed of 100 rpm. However, for the packaging material 9, a test piece was cut out from the packaging material after boiling, and for the packaging materials 12 to 14, the test piece was cut out from the packaging material after retort. The peeling time between the two substrates in contact with the desorption adhesive layer was measured and evaluated according to the following criteria.
〇: In less than 6 hours, all the substrates in contact with the desorbing adhesive layer are peeled off (good).
Δ: In 6 hours or more and less than 12 hours, all the substrates in contact with the desorption adhesive layer are peeled off (usable).
X: Even after 12 hours have passed, all the substrates in contact with the desorbing adhesive layer do not peel off (cannot be used).

(Removal rate 1)
For the packaging materials 1 to 18, test pieces having a size of 3.0 cm × 3.0 cm were cut out. However, for the packaging material 9, a test piece was cut out from the packaging material after boiling, and for the packaging materials 12 to 14, the test piece was cut out from the packaging material after retort. Each test piece is immersed and stirred in 50 g of a 2% sodium hydroxide aqueous solution at 70 ° C. at a rotation speed of 100 rpm for 12 hours to peel off the two substrates in contact with the desorbing adhesive layer, and then washed with water and dried. This was carried out to obtain a recycled base material for the second base material.
Using FT-IR, the presence or absence of adhesive absorption peaks was confirmed at a total of 5 locations, the edge and the center, of the surface of the obtained recycled base material that was in contact with the detachable adhesive layer. It was evaluated according to the following criteria. Those in which the two substrates in contact with the desorption adhesive layer did not peel off within 12 hours were not evaluated.
⊚: There is no adhesive absorption peak in all 5 places (removal rate is about 100%: very good).
◯: There is an adhesive absorption peak in only one of the five locations (removal rate is about 80%: good).
Δ: Adhesive absorption peaks are present at 2 to 3 of 5 locations (removal rate is about 40 to 60%: usable).
X: Adhesive absorption peaks are present at 4 or more of the 5 locations (removal rate is about 20%: cannot be used).

The abbreviations of Tables 3 and 4 are shown below.
NaOH: Sodium hydroxide Ink 1: Rio Alpha R631 white manufactured by Toyo Ink Co., Ltd. Ink 2: CCST 62 white manufactured by Toyo Ink Co., Ltd. Ink 3: NEW MAX 63 white manufactured by Toyo Ink Co., Ltd.

According to the results of Tables 3 and 4, at least the first base material, the printing layer, the polyurethane-based adhesive layer for desorbing the second base material, and the second base material are outer layers in this order. The packaging material of the present invention, which has a structure of being laminated from the side and is provided with the polyurethane-based adhesive layer in contact with the second base material, has only excellent adhesive strength at the initial stage and after boiling and retorting. In addition, the sealant base material, which is the second base material, is excellent in detachability, and the recyclability of the sealant base material can be enhanced.
In particular, Examples 5, 8 to 11 and 15 in which the acid value after blending the adhesive is 20 mgKOH / g or more and the polyisocyanate component is a derivative derived from hexamethylene diisocyanate have good desorption. The removal rate is shown.
In addition, Example 8 containing a polyester polyol having a number average molecular weight of less than 3,000 was superior in initial adhesive strength as compared with Example 5.

<Evaluation of packaging materials 19 to 31>
The following evaluations were carried out using the obtained packaging materials 19 to 31. The results are shown in Table 6.

(Adhesive strength: initial)
Using the packaging materials 19 to 31, the lamination strength (N / 15 mm) between the two substrates in contact with the polyurethane-based desorbing adhesive layer is determined in the same manner as in the above-mentioned packaging materials 1 to 18 (adhesive strength: initial). It was measured.
(Removability 2)
A test piece having a size of 3.0 cm × 3.0 cm was cut out from the packaging materials 19 to 31, and immersed and stirred in 50 g of a 2% aqueous solution of sodium hydroxide (NaOH) at 70 ° C. at a rotation speed of 50 rpm. The time for peeling between OPP and CPP was measured and evaluated according to the following criteria.
⊚: All peeling between OPP and CPP within 20 minutes (very good)
◯: All peeling between OPP and CPP within 20 minutes or more and 1 hour (good)
Δ: Within 1 hour or more and 12 hours or less, all the OPP and CPP are peeled off (usable).
X: No peeling between OPP and CPP within 12 hours (cannot be used)

(Removal rate 2)
A test piece having a size of 3.0 cm × 3.0 cm was cut out from the packaging materials 19 to 31, and immersed and stirred in 50 g of a 2% aqueous solution of sodium hydroxide (NaOH) at 70 ° C. at a rotation speed of 50 rpm for 1 hour. After peeling between OPP and CPP, the film was washed with water and dried to obtain a recycled CPP film having a size of 3.0 cm × 3.0 cm. Using FT-IR, the presence or absence of adhesive absorption peaks was confirmed at a total of 5 locations, the four ends and the center of the surface of the obtained recycled CPP film that was in contact with the detachable adhesive layer. , Evaluated according to the following criteria. If the OPP and CPP did not peel off within 1 hour, it was not evaluated.
⊚: There is no adhesive absorption peak in all 5 places (removal rate is about 100%: very good).
◯: There is an adhesive absorption peak in only one of the five locations (removal rate is about 80%: good).
Δ: Adhesive absorption peaks are present at 2 to 3 of 5 locations (removal rate is about 40 to 60%: usable).
X: Adhesive absorption peaks are present at 4 or more of the 5 locations (removal rate is about 20%: cannot be used).

According to the results in Table 6 above, the desorption properties of Examples 17 to 28 to which phosphoric acid or a phosphoric acid derivative was added were improved as compared with Example 16. Further, as compared with Examples 18 and 22, Examples 23 to 28 to which fine particles having an average particle size of 1 to 10 μm were added in addition to phosphoric acid had improved desorption or removal rate.

<Evaluation of packaging materials 32 to 34>
The following evaluations were carried out using the obtained packaging materials 32 to 34. The results are shown in Table 7.

(Adhesive strength: initial)
Using the packaging materials 32 to 34, the lamination strength (N / 15 mm) between ^{PET / LDPE EXT} was measured in the same manner as in the above-mentioned packaging materials 1 to 18 (adhesive strength: initial).

(Adhesive strength: after boiling)
Using the packaging materials 32 to 34, a pouch having a size of 21 cm × 30 cm was prepared, and water was vacuum-filled as the content. The obtained pouch was boiled at 85 ° C. for 30 minutes.
A test piece having a size of 15 mm × 300 mm was prepared from the boiled pouch, and the lamination strength (N / 15 mm) between ^{PET / LDPE EXT was measured in the same manner as the initial adhesive strength.}

(Removability 3)
Three test pieces having a size of 2.0 cm × 2.0 cm are cut out from the pouch after the boil treatment, and immersed and stirred in 50 g of a 2% aqueous solution of sodium hydroxide (NaOH) at 70 ° C. at a rotation speed of 100 rpm. Was done. The time for peeling between PET and LDPEEXT was measured and evaluated according to the following criteria.
⊚: Within 20 minutes, all the parts between PET and LDPEEXT are peeled off (very good).
◯: All peeling between PET and LDPEEXT within 20 minutes or more and 1 hour (good)
Δ: Within 1 hour or more and 12 hours or less, all the parts between PET and LDPEEXT are peeled off (usable).
X: Within 12 hours, all PET and LDPEEXT do not peel off (cannot be used).

(Removal rate 3)
A test piece having a size of 2.0 cm × 2.0 cm was cut out from the pouch after the boil treatment, and immersed and stirred in 50 g of a 2% aqueous solution of sodium hydroxide (NaOH) at 70 ° C. at a rotation speed of 100 rpm for 1 hour. After peeling between PET and LDPEEXT, washing with water and drying were carried out to obtain a recycled PE film having a size of 2.0 cm × 2.0 cm.
Using FT-IR, the presence or absence of adhesive absorption peaks was confirmed at a total of 5 locations, the four ends and the center of the surface of the obtained recycled PE film that was in contact with the detachable adhesive layer. , Evaluated according to the following criteria. Those in which the PET and LDPEEXT did not peel off within 1 hour were not evaluated.
⊚: There is no adhesive absorption peak in all 5 places (removal rate is about 100%: very good).
◯: There is an adhesive absorption peak in only one of the five locations (removal rate is about 80%: good).
Δ: Adhesive absorption peaks are present at 2 to 3 of 5 locations (removal rate is about 40 to 60%: usable).
X: Adhesive absorption peaks are present at 4 or more of the 5 locations (removal rate is about 20%: cannot be used).

The abbreviations in Table 7 are shown below.
NaOH: Sodium hydroxide ink 4: Made by Toyo Ink Co., Ltd. Rio Alpha R39 Indigo,
Ink 5: Rio Alpha R631 White manufactured by Toyo Ink Co., Ltd.

According to the results in Table 7 above, the packaging materials 32 to 34 in which the second base material is laminated by extrusion lamination have a thinner removable adhesive layer than ordinary dry lamination, but have good alkalinity. In addition to detachability and removal rate, it showed excellent lamination strength.

Claims (12)

A packaging material having a structure in which at least a first base material, a printing layer, a polyurethane adhesive layer for desorbing a second base material, and a second base material are laminated from the outer layer side in this order. And
A packaging material in which the polyurethane-based adhesive layer is provided in contact with the second base material. The polyurethane-based adhesive layer is a cured product of an adhesive containing a polyol component and a polyisocyanate component.
The packaging material according to claim 1, wherein the polyol component contains a polyester polyol. The packaging material according to claim 2, wherein the polyester polyol has a urethane bond. The packaging material according to claim 2 or 3, wherein the polyisocyanate component contains at least one selected from the group consisting of an aliphatic polyisocyanate and an aromatic aliphatic polyisocyanate. The packaging material according to any one of claims 1 to 4, wherein the acid value of the adhesive is 5 to 45 mgKOH / g. The invention according to any one of claims 1 to 5, wherein the polyurethane-based adhesive layer further contains an oxygen acid of phosphorus or a derivative thereof in an amount of 0.01 to 5% by mass based on the mass of the polyurethane-based adhesive layer. Packaging material. The packaging material according to any one of claims 1 to 6, wherein the polyurethane-based adhesive layer further contains fine particles having an average particle size of 1 to 10 μm. The packaging material according to claim 7, wherein the content of the fine particles is 0.1 to 10% by mass based on the mass of the polyurethane-based adhesive layer. The packaging material according to any one of claims 1 to 8, wherein the thickness of the polyurethane-based adhesive layer is 1 to 6 μm. The packaging material according to any one of claims 1 to 9, wherein the second base material contains polyolefin. The packaging according to any one of claims 1 to 10, wherein the second base material is a layer laminated by extrusion lamination, and the thickness of the polyurethane-based adhesive layer is 0.01 to 1 μm. Material. A packaging container in which at least a part is formed of the packaging material according to any one of claims 1 to 11.