JP7822122B2 - Manufacturing method of adhesive body - Google Patents

Description

The present invention relates to a method for manufacturing an adhesive material used for food packaging, etc., and a method for manufacturing packaging containers using the adhesive material.

In food packaging, methods for sealing the contents include methods that melt and adhere sealant layers together, such as heat sealing or ultrasonic sealing, and methods that use adhesive materials such as hot melt adhesives to bond the contents together. One such method uses a rewettable adhesive layer, as exemplified by postage stamps (see, for example, Patent Documents 1 and 2), and packaging containers made by molding or otherwise processing the bonded body via the rewettable adhesive layer are being considered.

Patent No. 6423473 International Publication No. 2015-015605

However, the inventors' research has revealed that with conventional methods, the adhesive strength of the adhesive joints in packaging containers using adhesive bodies may not be sufficient, and that when a load is applied to the packaging container, blocking may occur due to the adhesive material protruding into the opening, making it difficult to open the packaging container.

Therefore, an object of the present invention is to provide a method for manufacturing an adhesive body capable of forming a packaging container with excellent adhesive strength and blocking resistance, and a method for manufacturing such a packaging container.

As a result of extensive research to solve the above-mentioned problems, the present inventors have discovered that the above-mentioned problems can be solved by a method for producing an adhesive body (Z) that includes the steps of: adjusting the water content of the adhesive layer (A) contained in the laminate (X) to 3 to 20% by mass; applying liquid (W) to 1 to 50% by area of the adhesive layer (A); and superimposing the adhesive layer (A) of the laminate (X) on the structure (Y) and applying pressure to the superimposed laminate (X) and structure (Y) in a pressure region (III); or folding the laminate (X) so that the adhesive layers (A) face each other or the adhesive layer (A) faces a layer other than the adhesive layer (A) and applying pressure to the folded laminate (X) in a pressure region (III'). Based on this discovery, the present invention has been completed. Specifically, the present invention includes the following aspects.

[1] A method for producing a bonded body (Z) obtained by bonding a laminate (X) including an adhesive layer (A) to a structure (Y), wherein the moisture content of the adhesive layer (A) is 3 to 20 mass %,
A step (I) of applying the liquid (W) to a coating area of 1 to 50 area % of the total area of the adhesive layer (A);
a step (II) of superposing the adhesive layer (A) of the laminate (X) on the structure (Y); and a step (III) of pressing the superposed laminate (X) and structure (Y) in a pressure region.
A method comprising:
[2] A method for producing an adhesive body (Z) comprising a laminate (X) containing an adhesive layer (A), wherein the moisture content of the adhesive layer (A) is 3 to 20 mass %,
A step (I) of applying the liquid (W) to a coating area of 1 to 50 area % of the total area of the adhesive layer (A);
a step (II') of folding the laminate (X) so that the adhesive layers (A) face each other or the adhesive layers (A) face a layer other than the adhesive layer (A); and a step (III') of pressing the folded laminate (X) in a pressurizing region.
A method comprising:
[3] The method according to [1] or [2], wherein the oxygen permeability of the adhesive layer (A) is 0.01 to 10 mL.20 μm/(m ² .day.atm).
[4] The method according to any one of [1] to [3], wherein the laminate (X) further contains paper (C).
[5] The method according to any one of [1] to [4], wherein the pressurized region is heated in steps (III) and (III').
[6] The method according to any one of [1] to [5], wherein in step (I), the coating amount of the liquid (W) in the coating area is 10 to 30 g/ ^m2 .
[7] The method according to any one of [1] to [6], wherein in step (I), the liquid (W) contains 50 mass% or more of water and has a viscosity of 0.3 to 100 cP.
[8] The method according to any one of [1] to [7], wherein in step (I), a water supply roll (R) is brought into contact with the coating area of the adhesive layer (A) to coat the liquid (W).
[9] The method according to any one of [1] to [8], wherein in step (I), the liquid (W) is applied to the application area of the adhesive layer (A) using a slit coater.
[10] The method according to any one of [1] to [9], wherein in step (I), the liquid (W) is sprayed onto the application area of the adhesive layer (A).
[11] The method according to any one of [1] to [7], comprising a combination of two or more methods selected from the group consisting of a method in which, in step (I), a method in which the liquid (W) is applied by bringing a water supply roll (R) into contact with the application area of the adhesive layer (A); a method in which the liquid (W) is applied to the application area of the adhesive layer (A) using a slit coater; and a method in which the liquid (W) is sprayed onto the application area of the adhesive layer (A).
[12] The method according to any one of [1] to [11], wherein in steps (III) and (III'), the pressure region is heated to 80 to 200°C.
[13] The method according to any one of [1] to [12], wherein in step (I), the liquid (W) contains at least one selected from the group consisting of an alcohol-based solvent, a polyvinyl alcohol-based resin, gelatin, xanthan gum, carrageenan, guar gum, carrageenan, sodium carboxymethylcellulose, and pectin.
[14] The method according to any one of [1] and [3] to [13], wherein the structure (Y) is a laminate (X') including an adhesive layer (A) or a laminate (Q) not including an adhesive layer (A).
[15] The method according to [14], wherein in step (II), the adhesive layer (A) of the laminate (X) and the adhesive layer (A) of the laminate (X') are superposed so as to be in contact with each other.
[16] The method according to any one of [1] to [15], wherein in steps (III) and (III'), the area of the pressurized region is 1 to 50 area % of the total area of the adhesive layer (A).
[17] The method according to any one of [1] to [16], wherein in steps (III) and (III'), the width of the pressurized region in the lateral direction is 5 to 30 mm.
[18] The method according to any one of [1] to [17], wherein in steps (III) and (III'), the area of the pressurized region is 0.5 to 1.5 times the area of the coated region, and includes an overlapping portion between the pressurized region and the coated region.
[19] The method according to any one of [1] to [18], wherein the area of the overlapping portion between the pressurized region and the applied region is 0.5 to 1.5 times the area of the pressurized region.
[20] A method for producing a packaging container using the adhesive (X) obtained by the method according to any one of [1] to [19].
[21] The method according to [20], wherein the packaging container is a flat pouch, a standing pouch, a gusset pouch, a twin pouch, or a spout pouch, a thermoformed container, or an injection-molded container.

The manufacturing method of the present invention makes it possible to form an adhesive body and packaging container that can be used to form packaging containers with excellent adhesive strength and blocking resistance.

1 is a schematic cross-sectional view showing the layer structure of a laminate according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a method for applying a liquid using a water supply roll in step (I) according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a process for overlapping the adhesive layer (A) of the laminate (X) and the structure (Y) in step (II) in one embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a process in which the stacked laminate (X) and structure (Y) are pressed in a pressurizing region in step (III) in one embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a process in which the stacked laminate (X) and structure (Y) are pressed in a pressurizing region in step (III) in one embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a process in which the stacked laminate (X) and structure (Y) are pressed in a pressurizing region in step (III) in one embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a process in which the stacked laminate (X) and structure (Y) are pressed in a pressurizing region in step (III) in one embodiment of the present invention. 1 is a schematic diagram showing an adhesive body according to one embodiment of the present invention and a cutting line of the adhesive body. 1 is a schematic diagram showing a three-sided pouch in one embodiment of the present invention. 1 is a schematic diagram showing a water supply roll and a receiving tray according to an embodiment of the present invention. FIG. 10 is a schematic view showing a water supply roll and a receiving tray of Comparative Example 5. 1 is a schematic diagram showing a water supply roll according to one embodiment of the present invention. 1 is a schematic diagram showing a gusset pouch in one embodiment of the present invention. 1 is a schematic diagram showing a standing pouch in one embodiment of the present invention. 1 is a schematic diagram showing a twin pouch in one embodiment of the present invention. 1 is a schematic diagram showing a spout pouch in one embodiment of the present invention. 1 is a schematic cross-sectional view showing an adhesive bonded body (packaging container) according to one embodiment of the present invention.

The present invention is a method for producing an adhesive body (Z) formed by bonding a laminate (X) containing an adhesive layer (A) to a structure (Y). The production method is characterized by comprising the steps of: (I) applying a liquid (W) to a coating area of 1 to 50 area % of the total area of the adhesive layer (A); (II) overlapping the adhesive layer (A) of the laminate (X) with the structure (Y) and (III) applying pressure to the overlapped laminate (X) and structure (Y) in a pressure region; or (II') folding the laminate (X) so that the adhesive layers (A) face each other or so that the adhesive layer (A) faces a layer other than the adhesive layer (A) and applying pressure to the folded laminate (X) in a pressure region.

[Laminate]
The laminate (X) of the present invention includes an adhesive layer (A).
<Adhesive layer (A)>
The adhesive layer (A) is a layer that can be bonded by applying the liquid (W) and applying pressure. The adhesive layer (A) can be at least partially bonded to the laminate (X) of the present invention by applying the liquid (W) and applying pressure.

The moisture content of the adhesive layer (A) in the laminate (X) is 3 to 20% by mass. If the moisture content is less than 3% by mass, the adhesive strength of the resulting adhesive body (Z) tends to be low, while if the moisture content exceeds 20% by mass, the blocking resistance tends to be low. In the present invention, the moisture content is adjusted to 3 to 20% by mass, so that the resulting adhesive body (Z) can achieve both excellent adhesive strength (seal strength) and blocking resistance. In this specification, blocking resistance refers to the ease of opening the resulting adhesive body or packaging container (pouch); the higher the blocking resistance, the easier it is to open. Note that blocking refers to adhesion that exceeds the pressure range, preventing the intended opening. Furthermore, appearance characteristics refer to the degree of wrinkles and unevenness in the adhesive body (particularly in the adhesive joints), and improved appearance characteristics refer to the greater suppression of wrinkles and unevenness in the adhesive body (particularly in the adhesive joints).

The moisture content of the adhesive layer (A) in the laminate (X) is preferably 4% by mass or more, more preferably 5% by mass or more, even more preferably 6% by mass or more, and preferably 18% by mass or less, more preferably 15% by mass or less, and even more preferably 13% by mass or less. When the moisture content of the adhesive layer (A) is at or above the above lower limit, the adhesive strength and appearance characteristics tend to be improved. When the moisture content is at or below the above upper limit, the blocking resistance tends to be improved. The moisture content of the adhesive layer (A) in the laminate (X) can be measured using a moisture meter, for example, by the method described in the Examples. The moisture content can also be adjusted to within the above range by appropriately adjusting the storage temperature and humidity of the laminate (X). For example, increasing the storage humidity tends to increase the moisture content, while decreasing the storage humidity tends to decrease the moisture content. Furthermore, increasing the storage temperature or drying at high temperatures tends to decrease the moisture content.

From the viewpoint of easily improving biodegradability, gas barrier properties, and adhesive strength, the adhesive layer (A) preferably contains at least one selected from modified starch (a), water-soluble polymer (b), and ethylene-vinyl alcohol copolymer (c). In a preferred embodiment of the present invention, the adhesive layer (A) contains modified starch (a). In another preferred embodiment of the present invention, the adhesive layer (A) contains ethylene-vinyl alcohol copolymer (c). In such an embodiment, it is easier to further improve biodegradability, gas barrier properties, and adhesive strength. Adhesive strength refers to the strength of the adhesive at the bonded portion in the resulting adhesive body or packaging container.

(Modified starch (a))
As the modified starch (a), for example, at least one selected from the group consisting of etherified starch, esterified starch, cationized starch, and crosslinked starch can be used.

Examples of starches include starches derived from cassava, corn, potato, sweet potato, sago, tapioca, sorghum, beans, bracken, lotus, water chestnut, wheat, rice, oats, arrowroot, and peas. Among these, starches derived from corn and cassava are preferred, and starch derived from high-amylose corn is even more preferred. Starches can be used alone or in combination of two or more types.

Examples of etherified starches include alkyl-etherified starches such as methyl-etherified starch; carboxyalkyl-etherified starches such as carboxymethyl-etherified starch; and hydroxyalkyl-etherified starches such as etherified starches having a hydroxyalkyl group with 2 to 6 carbon atoms. Allyl-etherified starches can also be used.

Esterified starches include those having structural units derived from carboxylic acids, such as those having structural units derived from acetic acid; those having structural units derived from dicarboxylic acid anhydrides, such as those having structural units derived from maleic anhydride, phthalic anhydride, and octenylsuccinic anhydride; and those having structural units derived from oxoacids, such as starch nitrate, starch phosphate, and starch urea phosphate. Other examples include xanthate-esterified starch and acetoacetate-esterified starch.

Examples of cationized starch include the reaction product of starch with 2-diethylaminoethyl chloride and the reaction product of starch with 2,3-epoxypropyltrimethylammonium chloride.

Examples of cross-linked starches include formaldehyde-cross-linked starch, epichlorohydrin-cross-linked starch, phosphate-cross-linked starch, and acrolein-cross-linked starch.

Preferred modified starch (a) is etherified starch having a hydroxyalkyl group with 2 to 6 carbon atoms, esterified starch having structural units derived from dicarboxylic acid anhydride, or a combination thereof, with hydroxyethyl etherified starch, hydroxypropyl etherified starch, hydroxybutyl etherified starch, esterified starch having structural units derived from maleic anhydride, esterified starch having structural units derived from phthalic anhydride, esterified starch having structural units derived from octenylsuccinic anhydride, or a combination thereof being more preferred. Modified starch (a) can be used alone or in combination of two or more types.

The amylose content in modified starch (a) is preferably 45% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, and particularly preferably 60% by mass or more. An amylose content above the above lower limit tends to improve biodegradability, gas barrier properties, and adhesive strength. The amylose content in modified starch (a) is usually 90% by mass or less. The amylose content can be measured, for example, by the iodine coloration method described in "Starch 50 No. 4 158-163 (1998)." When two or more types of modified starch are used, the amylose content of modified starch (a) refers to the average amylose content, calculated as a weighted average of the amylose contents of the two or more types of modified starches.

The moisture content of the modified starch (a) is preferably 10 to 15% by mass.

Etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms may be obtained by reacting starch with an alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide. The average number of hydroxy groups used for modification is preferably 0.05 to 2 per glucose unit in the starch.

Commercially available modified starch (a) can also be used. A typical commercially available example of modified starch (a) is ECOFILM (registered trademark), a hydroxypropyl etherified starch available from Ingredion.

(Water-soluble polymer (b))
The water-soluble polymer (b) is preferably polyvinyl alcohol, from the viewpoint of easily increasing adhesive strength and gas barrier properties. The water-soluble polymer (b) may be used alone or in combination of two or more kinds.

The polyvinyl alcohol preferably has a saponification degree of 80 to 99.8 mol%. When the saponification degree of polyvinyl alcohol is within the above range, it tends to be easier to improve adhesive strength and gas barrier properties. The saponification degree is more preferably 85 mol% or higher, even more preferably 88 mol% or higher, and particularly preferably 90 mol% or higher. The saponification degree indicates the molar fraction of hydroxyl groups relative to the total of hydroxyl groups and ester groups in polyvinyl alcohol. Polyvinyl alcohol is produced, for example, by hydrolysis of polyvinyl acetate obtained by polymerization of vinyl acetate monomer.

The viscosity of a 4% aqueous solution of polyvinyl alcohol at 20°C, measured in accordance with JIS Z 8803, is preferably 1 to 50 mPa·s. When the viscosity of polyvinyl alcohol is within the above range, it tends to be easier to improve adhesive strength and gas barrier properties. The viscosity is preferably 3 mPa·s or more, more preferably 5 mPa·s or more, and preferably 45 mPa·s or less, more preferably 35 mPa·s or less.

Polyvinyl alcohol may further contain other monomer units in addition to vinyl alcohol units. Examples of other monomer units include monomer units derived from ethylenically unsaturated monomers. Examples of ethylenically unsaturated monomers include α-olefins such as ethylene, propylene, n-butene, isobutylene, and 1-hexene; acrylic acid and its salts; unsaturated monomers having an acrylic ester group; methacrylic acid and its salts; unsaturated monomers having a methacrylic ester group; acrylamide, N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetoneacrylamide, acrylamidopropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts (e.g., quaternary salts); methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidopropanesulfonic acid and its salts, methacrylamidopropyldimethylamine and its salts (e.g., quaternary salts); methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, vinyl halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate, 2,3-diacetoxy-1-allyloxypropane and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid, and salts or esters thereof; vinyl silyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; and vinyl ester monomers such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl carboxylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate and vinyl benzoate. The content of other monomer units is preferably 10 mol% or less, and more preferably 5 mol% or less.

There are no particular restrictions on the method for producing polyvinyl alcohol. For example, a method can be used in which vinyl alcohol monomer and, optionally, other monomers are polymerized, and the resulting polymer is then saponified to convert it into vinyl alcohol units. Polymerization methods include batch polymerization, semi-batch polymerization, continuous polymerization, and semi-continuous polymerization. Polymerization methods include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Known methods can be used to saponify the polymer. For example, saponification can be performed in a state in which the polymer is dissolved in alcohol or aqueous alcohol. Examples of alcohols that can be used in this case include lower alcohols such as methanol and ethanol.

(Ethylene-vinyl alcohol copolymer (c))
Ethylene-vinyl alcohol copolymer (c) (hereinafter also referred to as EVOH (c)) is a polymer having ethylene units and vinyl alcohol units as main structural units. EVOH (c) may contain one or more types of other structural units in addition to the ethylene units and vinyl alcohol units. EVOH (c) is usually obtained by polymerizing ethylene and a vinyl ester and saponifying the resulting ethylene-vinyl ester copolymer.

In EVOH (c), the ethylene unit content (i.e., the ratio of ethylene units to the total molar amount of monomer units in EVOH (c)) is preferably 2 mol% or more, more preferably 10 mol% or more, even more preferably 20 mol% or more, and preferably 60 mol% or less, more preferably 50 mol% or less, even more preferably 40 mol% or less. An ethylene unit content within the above range is advantageous from the standpoint of gas barrier properties and mechanical properties. A lower ethylene unit content tends to result in a lower oxygen transmission rate (OTR).

In EVOH (c), the saponification degree of the vinyl alcohol unit is preferably 90 mol% or more, more preferably 95 mol% or more, even more preferably 99 mol% or more, and particularly preferably 99.5 mol% or more. When the saponification degree is within the above range, excellent gas barrier properties can be obtained. The saponification degree refers to the molar fraction of hydroxyl groups relative to the total of hydroxyl groups and ester groups in the vinyl alcohol unit.
The EVOH (c) may be used together with the modified starch (a) and the water-soluble polymer (b).

EVOH (c) preferably has at least one of the structural unit (I) represented by the following formula (I), the structural unit (II) represented by the following formula (II), and the structural unit (III) represented by the following formula (III). EVOH (c) having such a structural unit tends to improve the adhesive strength, appearance characteristics, gas barrier properties, flex resistance, etc. of the resulting bonded body or packaging container.

In the above formula (I), R ¹ , R ² and R ³ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group. Any pair of R ¹ , R ² and R ³ may be bonded to one another. Some or all of the hydrogen atoms in the aliphatic hydrocarbon group having 1 to 10 carbon atoms, the alicyclic hydrocarbon group having 3 to 10 carbon atoms, and the aromatic hydrocarbon group having 6 to 10 carbon atoms may be substituted with a hydroxyl group, a carboxyl group, or a halogen atom.

In formula (II), R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group. R ⁴ and R ⁵ , or R ⁶ and R ⁷ , may be bonded to each other. Some or all of the hydrogen atoms in the aliphatic hydrocarbon group having 1 to 10 carbon atoms, the alicyclic hydrocarbon group having 3 to 10 carbon atoms, and the aromatic hydrocarbon group having 6 to 10 carbon atoms may be substituted with a hydroxyl group, an alkoxy group, a carboxyl group, or a halogen atom.

In formula (III), R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group. Some or all of the hydrogen atoms in the aliphatic hydrocarbon group having 1 to 10 carbon atoms, the alicyclic hydrocarbon group having 3 to 10 carbon atoms, and the aromatic hydrocarbon group having 6 to 10 carbon atoms may be substituted with a hydroxyl group, an alkoxy group, a carboxyl group, or a halogen atom. ^{R 12} and R ¹³ each independently represent a hydrogen atom, a formyl group, or an alkanoyl group having 2 to 10 carbon atoms.

The content of structural units (I), (II), or (III) relative to the total structural units is preferably 0.5 mol% or more, more preferably 1 mol% or more, and even more preferably 1.5 mol% or more. On the other hand, the content of structural units (I), (II), or (III) is preferably 30 mol% or less, more preferably 15 mol% or less, and even more preferably 10 mol% or less. When EVOH (c) contains the structural units shown in (I), (II), or (III) in the above proportions within the above ranges, the adhesive strength, appearance characteristics, gas barrier properties, flexibility, processability, thermoformability, etc. of the resulting adhesive body or packaging container are likely to be improved.

In structural units (I), (II), and (III), examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms include alkyl groups and alkenyl groups, examples of alicyclic hydrocarbon groups having 3 to 10 carbon atoms include cycloalkyl groups and cycloalkenyl groups, and examples of aromatic hydrocarbon groups having 6 to 10 carbon atoms include phenyl groups.

In the structural unit (I), R ¹ , R ² , and R ³ are preferably each independently a hydrogen atom, a methyl group, an ethyl group, a hydroxyl group, a hydroxymethyl group, or a hydroxyethyl group, and among these, are more preferably each independently a hydrogen atom, a methyl group, a hydroxyl group, or a hydroxymethyl group. By using such R ¹ , R ² , and R ³ , the adhesive strength, appearance characteristics, gas barrier properties, flexibility, processability, thermoformability, etc. of the resulting adhesive body or packaging container can be easily improved.

There are no particular limitations on the method for incorporating structural unit (I) into EVOH (c), but examples include copolymerizing a monomer derived from structural unit (I) during the polymerization of ethylene and vinyl ester described above. Monomers derived from this structural unit (I) include alkenes such as propylene, butylene, pentene, and hexene; 3-hydroxy-1-propene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-hydroxy-1-butene, 4-acyloxy-3-hydroxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4-hydroxy-1-pentene, 5-hydroxy-1-pentene, Examples of alkenes having a hydroxyl group or an ester group include 4,5-dihydroxy-1-pentene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, 4-hydroxy-3-methyl-1-pentene, 5-hydroxy-3-methyl-1-pentene, 4,5-dihydroxy-3-methyl-1-pentene, 5,6-dihydroxy-1-hexene, 4-hydroxy-1-hexene, 5-hydroxy-1-hexene, 6-hydroxy-1-hexene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-hexene, and 5,6-diacyloxy-1-hexene. Among these, propylene, 3-acetoxy-1-propene, 3-acetoxy-1-butene, 4-acetoxy-1-butene, and 3,4-diacetoxy-1-butene are preferred from the standpoint of copolymerization reactivity and the gas barrier properties of the resulting adhesive or packaging container. In the case of alkenes having an ester, they are derived into the structural unit (I) described above during the saponification reaction.

In the structural unit (II), it is preferable that ^R4 and ^R5 are both hydrogen atoms. In particular, it is more preferable that ^R4 and ^R5 are both hydrogen atoms, and one of ^R6 and ^R7 is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and the other is a hydrogen atom. This aliphatic hydrocarbon group is preferably an alkyl group or an alkenyl group. From the viewpoint of easily improving the gas barrier properties of the resulting adhesive body or packaging container, it is particularly preferable that one of ^R6 and ^R7 is a methyl group or an ethyl group, and the other is a hydrogen atom. It is also particularly preferable that one of ^R6 and ^R7 is a substituent represented by ( _CH2 ) _hOH (wherein h is an integer of 1 to 8), and the other is a hydrogen atom. In this substituent represented by ( _CH2 ) _hOH , h is preferably an integer of 1 to 4, more preferably 1 or 2, and particularly preferably 1.

The method for incorporating structural unit (II) into EVOH (c) is not particularly limited, but one method that can be used is to incorporate it by reacting a monofunctional epoxy compound with EVOH obtained by a saponification reaction. Suitable monofunctional epoxy compounds are compounds represented by the following formulas (IV) to (X).

In formulas (IV) to (X), R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms (such as an alkyl group or an alkenyl group), an alicyclic hydrocarbon group having 3 to 10 carbon atoms (such as a cycloalkyl group or a cycloalkenyl group), or an aliphatic hydrocarbon group having 6 to 10 carbon atoms (such as a phenyl group). In addition, i, j, k, p and q each independently represent an integer of 1 to 8.

Examples of monofunctional epoxy compounds represented by formula (IV) include epoxyethane (ethylene oxide), epoxypropane, 1,2-epoxybutane, 2,3-epoxybutane, 3-methyl-1,2-epoxybutane, 1,2-epoxypentane, 3-methyl-1,2-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 3-methyl-1,2-epoxyhexane, 3-methyl-1,2-epoxyheptane, 4-methyl-1,2-epoxyheptane, 1,2-epoxyoctane, 2,3-epoxyoctane, 1,2-epoxynonane, 2,3-epoxynonane, 1,2-epoxydecane, 1,2-epoxydodecane, epoxyethylbenzene, 1-phenyl-1,2-epoxypropane, and 3-phenyl-1,2-epoxypropane. Examples of monofunctional epoxy compounds represented by formula (V) include various alkyl glycidyl ethers. Examples of monofunctional epoxy compounds represented by formula (VI) include various alkylene glycol monoglycidyl ethers. Examples of monofunctional epoxy compounds represented by formula (VII) include various alkenyl glycidyl ethers. Examples of monofunctional epoxy compounds represented by formula (VIII) include various epoxy alkanols such as glycidol. Examples of monofunctional epoxy compounds represented by formula (IX) include various epoxy cycloalkanes. Examples of monofunctional epoxy compounds represented by formula (X) include various epoxy cycloalkenes.

Among monofunctional epoxy compounds, epoxy compounds having 2 to 8 carbon atoms are preferred. In particular, from the viewpoints of ease of compound handling and reactivity, monofunctional epoxy compounds having 2 to 6 carbon atoms are more preferred, and 2 to 4 carbon atoms are even more preferred. Furthermore, among the monofunctional epoxy compounds, compounds represented by formula (IV) and (V) are particularly preferred. Specifically, from the viewpoints of reactivity with EVOH (c) and ease of improving the gas barrier properties of the resulting adhesive or packaging container, 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, epoxyethane, and glycidol are preferred, with epoxypropane and glycidol being particularly preferred.

In the structural unit (III), R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are preferably a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. Particularly preferred examples of the aliphatic hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group and a pentyl group.

The method for incorporating structural unit (III) into EVOH (c) is not particularly limited, but it can be produced, for example, by the method described in JP-A-2014-034647.

The adhesive layer (A) of the laminate (X) of the present invention may further contain a fatty acid having 12 to 22 carbon atoms and/or a fatty acid salt thereof. Examples of fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof include stearic acid, calcium stearate, sodium stearate, palmitic acid, lauric acid, myristic acid, linoleic acid, and behenic acid. Of these, stearic acid, calcium stearate, and sodium stearate are preferred from the viewpoint of processability. The fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof can be used alone or in combination of two or more.

When the adhesive layer (A) contains a fatty acid and/or a fatty acid salt thereof having 12 to 22 carbon atoms, the content in the adhesive layer is preferably 0.01 to 3 mass%, more preferably 0.03 to 2 mass%, and even more preferably 0.1 to 1 mass%, relative to the mass of the adhesive layer (A). Having the content of the fatty acid and/or the fatty acid salt thereof having 12 to 22 carbon atoms within the above range tends to be advantageous in terms of processability.

The adhesive layer (A) may further contain clay. Examples of clay include synthetic or natural layered silicate clays such as montmorillonite, bentonite, beidellite, mica, hectorite, saponite, nontronite, sauconite, vermiculite, ledikite, magadite, kenyaite, stevensite, and vulkonskoite. Clays can be used alone or in combination.

When the adhesive layer (A) contains clay, the content in the adhesive layer (A) is preferably 0.1 to 5 mass%, more preferably 0.1 to 3 mass%, and even more preferably 0.5 to 2 mass%, relative to the mass of the adhesive layer (A). A clay content within the above range tends to be advantageous in terms of transparency and strength.

The adhesive layer (A) in the laminate (X) of the present invention contains water, and as described above, its water content is 3 to 20% by mass. The adhesive layer (A) may also contain plasticizers other than water. Examples of plasticizers include sorbitol, glycerol, maltitol, xylitol, mannitol, glycerol trioleate, epoxidized linseed oil, epoxidized soybean oil, tributyl citrate, acetyltriethyl citrate, glyceryl triacetate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, polyethylene oxide, and polyethylene glycol. Plasticizers can be used alone or in combination.

The adhesive layer (A) may further contain additives such as fillers, processing stabilizers, weathering stabilizers, colorants, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, flame retardants, other thermoplastic resins, lubricants, fragrances, antifoaming agents, deodorizers, extenders, release agents, mold release agents, reinforcing agents, crosslinking agents, mildew inhibitors, preservatives, and crystallization rate retarders, as required.

The adhesive layer (A) is preferably in the form of a film or sheet. From the viewpoint of easily improving adhesive strength, biodegradability, gas barrier properties, and appearance characteristics, the thickness of the adhesive layer (A) is preferably 0.1 μm or more, more preferably 1 μm or more, and particularly preferably 10 μm or more, and is preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 100 μm or less. The thickness of the adhesive layer (A) can be measured using an optical microscope or a film thickness meter, for example, by the method described in the Examples. One or more adhesive layers (A) may be provided, and may be single-layer or multi-layer. When the adhesive layer (A) is two or more layers, the thickness and composition of each layer may be different or the same.

The adhesive layer (A) has excellent gas barrier properties, particularly oxygen barrier properties. The oxygen permeability (mL.20 μm/(m ² .day.atm)) of the adhesive layer (A) at 23°C and 50% RH is preferably 10.0 or less, more preferably 8.0 or less, even more preferably 6.0 or less, even more preferably 4.0 or less, particularly preferably 2.0 or less, and most preferably 1.0 or less. When the oxygen permeability is below the above upper limit, the resulting adhesive body (Z) can exhibit excellent oxygen barrier properties. The oxygen permeability can be measured using an oxygen permeation rate measuring device after storing the adhesive layer (A) at 23°C and 50% RH for two weeks and adjusting the humidity, for example, by the method described in the Examples. Here, for example, an oxygen permeability of "10 mL.20 μm/(m ² .day.atm)" means that 10 mL of oxygen permeates per m ² of a 20 μm-thick film per day under oxygen gas pressure of 1 atmosphere.

Commercially available products can be used for the adhesive layer (A). Representative commercially available products include "Plantic (registered trademark) HP 50" and "EVAL (registered trademark) F101B," both available from Kuraray Co., Ltd.

The laminate (X) of the present invention may further include a substrate layer (B).

<Base material layer (B)>
The substrate layer (B) is not particularly limited, and examples thereof include paper or a resin film. Examples of paper include, but are not limited to, kraft paper, fine paper, construction paper, glassine paper, parchment paper, synthetic paper, white cardboard, Manila cardboard, milk carton base paper, cup base paper, ivory paper, and silver paper. Among these, kraft paper and glassine paper are preferably used from the viewpoint of easily improving adhesion with the adhesive layer (A). Furthermore, the resin film is not particularly limited, and examples thereof include polyethylene terephthalate (PET) film, polypropylene (PP) film, polyethylene (PE) film (preferably low-density polyethylene (LDPE) film), and polylactic acid film. Among these, PET film and PP film are preferably used from the viewpoint of easily improving adhesion with the adhesive layer (A). The substrate layer is preferably paper from the viewpoint of easily improving adhesion with the adhesive layer (A) and biodegradability, that is, the laminate (X) preferably contains paper as the substrate layer (B).

The thickness of the substrate layer (B) is not particularly limited, and is preferably 1 to 1,000 μm, more preferably 1 to 500 μm, even more preferably 5 to 300 μm, and particularly preferably 10 to 200 μm. The thickness of the substrate layer (B) can be measured using an optical microscope or a film thickness meter, for example, by the method described in the Examples. One or more substrate layers (B) may be provided, and may be single-layer or multi-layer. When the substrate layer (B) has two or more layers, the thickness and material of each layer may be different or the same.

The laminate (X) of the present invention may include one or more adhesive layers (C) in addition to the adhesive layer (A) and the base layer (B). Examples of adhesives that constitute the adhesive layer (C) include acrylic adhesives, urethane adhesives, epoxy adhesives, vinyl acetate adhesives, ethylene-vinyl acetate adhesives, vinyl chloride adhesives, silicone adhesives, nitrile cellulose adhesives, phenolic adhesives, polyvinyl alcohol adhesives, melamine adhesives, and styrene adhesives. From the standpoint of adhesiveness, urethane adhesives are preferred. The thickness of the adhesive layer (C) is preferably 0.1 to 30 μm, more preferably 1 to 20 μm. The thickness of the adhesive layer (C) can be measured using an optical microscope or a film thickness meter, for example, by the method described in the Examples.

In one embodiment of the present invention, when the laminate (X) of the present invention has an adhesive layer (C), the adhesive layer (C) is preferably disposed between the adhesive layer (A) and the substrate layer (B). In a preferred embodiment of the present invention, the laminate (X) has the adhesive layer (A), adhesive layer (C), and substrate layer (B) in this order, or has the adhesive layer (A) and substrate layer (B) adjacent to each other.

The laminate (X) may include an adhesive layer (A), a substrate layer (B), an adhesive layer (C), and other layers. The other layers are not particularly limited and may include, for example, a protective layer, a gas barrier layer different from the adhesive layer (A), a moisture-proof layer, a light-blocking layer, a printed layer, a reinforcing layer, and a recovery layer (e.g., a layer formed by melt-kneading and remolding a laminate consisting of a substrate layer/adhesive layer/adhesive layer/substrate layer). Materials for forming the other layers include, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, EVOH, polyvinyl chloride, polyurethane, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamides such as nylon, polyacrylonitrile, cellulose or its derivatives, glass, and wood. One or more other layers may be provided, and they may be single-layered or multi-layered. When there are two or more other layers, the thicknesses and materials of the layers may be different or the same. The other layer may be laminated to the adhesive layer (A) or the base layer (B) via the adhesive layer (C). There are no particular limitations on the thickness of the other layer, but it is preferably 1 to 1000 μm, and more preferably 5 to 500 μm.

The shape of the laminate (X) is not limited to a sheet or film, and can be selected appropriately depending on the shape of the desired bonded body (Z). For example, when forming the bonded body (container) shown in Figure 17, the laminate (X) can be molded into the shape of the container (tray) body before step (I). The molding method is not particularly limited, and conventional methods such as thermoforming and injection molding can be used.

<Method for producing laminate (X)>
The method for producing the laminate (X) is not particularly limited, but examples include a method in which an adhesive layer (A) is produced, an adhesive layer (C) is formed on the obtained adhesive layer (A), and a base layer (B) is formed on the adhesive layer (C).

The adhesive layer (A) can be produced, for example, by a method including the steps of: (1) mixing at least one selected from modified starch (a), water-soluble polymer (b), and ethylene-vinyl alcohol copolymer (c), and optionally other components, such as the fatty acid having 12 to 22 carbon atoms and/or its fatty acid salt, the clay, the plasticizer, and the additives, to obtain a mixture; (2) extruding the mixture; and (3) cooling and drying the extruded mixture.

Step (1) is typically carried out using an extruder. In the extruder, the components are subjected to shear stress by the screw and are mixed homogeneously while being heated by applying external heat to the barrel.

As an extruder, for example, a twin-screw extruder can be used. Twin-screw extruders may be either co-rotating or counter-rotating. The screw diameter may be, for example, 20 to 150 mm, and the ratio of the extruder length (L) to the screw diameter (D), i.e., L/D, may be, for example, 20 to 50. The screw rotation speed is preferably 80 rpm or more, more preferably 100 rpm or more. The extrusion molding pressure is preferably 5 bar (0.5 MPa) or more, more preferably 10 bar (1.0 MPa) or more. Each component can be introduced directly into the extruder. Alternatively, these components may be premixed using a mixer and then introduced into the extruder.

In step (1), from the viewpoints of easily adjusting the water content of the adhesive layer (A) to 3 to 20% by mass and easily improving film-forming properties, it is preferable to mix water in an amount of preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, particularly preferably 15% by mass or more, and most preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to the mass of the mixture. Here, the mass of the mixture refers to the total mass of the mixture including water. In step (1), water may be introduced at the initial stage of extrusion, or before the temperature reaches the cooking temperature described below, for example, when the temperature is below 100°C. The modified starch (a) is cooked by a combination of moisture, heat, and shear stress, and can be gelatinized (gelated). Furthermore, by separately introducing water, the water-soluble polymer (b) can be dissolved, the mixture can be softened, and the modulus and brittleness can be reduced.

In step (1), the cooking treatment is preferably carried out by heating to a temperature of more than 100°C and not more than 150°C, more preferably from 115°C to 140°C. Here, cooking treatment is a process that crushes and gelates starch granules. Heating can be carried out by applying heat externally to the barrels of the extruder. By applying a temperature that changes in stages to each barrel, heating to the desired temperature can be achieved. Cooking treatment at a temperature above 120°C is advantageous in terms of processability.

The cooked mixture is preferably forced toward the die while the temperature is reduced to 85-120°C, more preferably 90-110°C, to prevent foaming. Also, venting the barrel prevents foaming and removes moisture.

The residence time in the extruder can be set depending on the temperature profile and screw speed, and is preferably 1 to 2.5 minutes.

In step (2) of extruding the mixture, the molten mixture that has been forced through the extruder while being melt-kneaded is extruded through a die. The die temperature is preferably 85 to 120°C, more preferably 90 to 110°C.

In step (3), the extruded mixture is cooled and dried, and the adhesive layer (A) can be formed by extruding the mixture into a film or sheet. The extruded mixture is usually in the form of a melt.

When the mixture is extruded into a film, it can be cooled and dried while being extruded through a film-forming die and then wound up on a take-up roller. Cooling between the die and the roller is preferred to prevent the mixture from sticking to the roller. For drying, the roll may be heated, and dehumidified air may be supplied during winding. In the case of the blown tube method, dehumidified air can be used to expand the film as it exits the die. Talc can also be entrained in the air stream to prevent film blocking.

The method for forming the adhesive layer (C) on the adhesive layer (A) is not particularly limited, but examples include a method in which the adhesive that constitutes the adhesive layer (C) is applied to the adhesive layer (A) and then dried.

The method for forming the base layer (B) on the adhesive layer (C) is not particularly limited, but examples include a method in which the base layer (B) is layered on the adhesive layer (C) and then laminated. The laminate (X) of the present invention may also be produced by extruding the mixture onto the base layer (B) using the extruder described above. It may also be produced by a sand lamination method in which the adhesive layer (C) is extruded between the adhesive layer (A) and the base layer (B).

[Structure (Y)]
The structure (Y) in the present invention is not particularly limited, and may include, for example, at least one selected from the adhesive layer (A), the base layer (B), the adhesive layer (C), and the other layers. The structure (Y) may be a single layer or a laminate. When the structure (Y) includes one or more of the adhesive layer (A), the base layer (B), and the adhesive layer (C), the structure (Y) may have the same composition and film thickness as or different from the adhesive layer (A), the base layer (B), and the adhesive layer (C) that constitute the laminate (X).

In one embodiment of the present invention, the structure (Y) is a laminate (X') including an adhesive layer (A) or a laminate (Q) not including an adhesive layer (A), and is preferably a laminate (X') including an adhesive layer (A) from the viewpoint of easily increasing adhesive strength. In particular, when the structure (Y) is a laminate (X') and an adhesive structure formed by bonding (sealing) the adhesive layer (A) of the laminate (X) with the adhesive layer (A) of the laminate (X') is easily able to exhibit superior adhesive strength.
The laminate (X') is a laminate including the adhesive layer (A) and may include, in addition to the adhesive layer (A), at least one layer selected from the base material layer (B), the adhesive layer (C), and the other layers. The laminate (X') may be the same as or different from the laminate (X), but is preferably the same as the laminate (X) from the viewpoint of easily improving gas barrier properties, biodegradability, appearance characteristics, and adhesive strength.
The laminate (Q) is a laminate that does not include the adhesive layer (A) and can include, for example, at least one layer selected from the base material layer (B), the adhesive layer (C), and the other layer.

The layer structure of the structure (Y) is not particularly limited, but examples thereof include a layer structure having a substrate layer (B)/adhesive layer (C)/adhesive layer (A) in this order; a layer structure having another layer/adhesive layer (C)/substrate layer (B)/adhesive layer (A) in this order; a layer structure having another layer/substrate layer (B)/adhesive layer (A) in this order; a layer structure having a substrate layer (B)/adhesive layer (C)/adhesive layer (A)/adhesive layer (C)/substrate layer (B) in this order; a substrate Examples of such a layer structure include a layer structure having, in this order, layer (B)/another layer/adhesive layer (C)/adhesive layer (A)/adhesive layer (C)/substrate layer (B); a layer structure having, in this order, substrate layer (B)/another layer/adhesive layer (C)/adhesive layer (A)/adhesive layer (C)/another layer/substrate layer (B); a layer structure having, in this order, substrate layer (B)/adhesive layer (C)/adhesive layer (A)/adhesive layer (C)/another layer/substrate layer (B); and a layer structure consisting of substrate layer (B). Structure (Y) can be produced, for example, by the method described in the section <Method for producing a laminate>.

[Method of manufacturing the bonded body]
Hereinafter, a method for producing a bonded structure according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings, although the production method of the present invention is not limited to this embodiment.

Figure 1 is a schematic diagram showing the layer structure of a laminate in one embodiment of the present invention, and Figures 2 to 8 are schematic diagrams showing a method for producing an adhesive body in one embodiment of the present invention. In this embodiment, laminate (X) uses laminate 1a having substrate layer 4a, adhesive layer 3a, and adhesive layer 2a, in that order, as shown in Figure 1, and laminate 1a is also used as structure (Y). When explaining the drawings, to ensure ease of viewing, (X), (Y), (A), and (W) will be omitted from terms such as laminate (X), structure (Y), adhesive layer (A), and liquid (W).

[Process (I)]
Step (I) is a step of applying the liquid (W) to a coating area of 1 to 50 area % of the total area of the adhesive layer (A). The coating area is the area on the surface of the adhesive layer (A) to which the liquid (W) is applied.

FIG. 2 is a schematic diagram showing an example of the process of applying the liquid (W) to the application area in step (I).
As shown in FIG. 2 , the water supply roll 7a has a sponge portion 6a attached to the outer periphery of the metal roll 5a, which can come into contact with the coating area while rotating. The sponge portion 6a contains liquid 8. As the laminate 1a is moved by the transport roll (not shown), the coating area on the adhesive layer 2a comes into contact with the sponge portion 6a of the rotatably fixed water supply roll 7a, thereby applying liquid 8 to the coating area while the water supply roll 7a rotates in the rotation direction 101. In this way, liquid 8 can be efficiently and continuously applied to the coating area, which is formed by two rectangular frames arranged along the width of the laminate 1a. The coating area accounts for 20 to 50 area percent of the total area of the adhesive layer 2a. From the perspective of production efficiency, the laminate 1a is usually wound by the unwinding roll, unwound from the unwinding roll, and transported by the transport roll.

In the embodiment shown in Figure 2, the water supply roll 7a is fixed and the laminate 1a is moved by a transport roll, but it is also possible to fix the laminate 1a and apply the liquid 8 by rolling the water supply roll over the application area.

The adhesive layer (A) exhibits sealing properties when it comes into contact with the liquid (W), and is then adhered to the structure (Y) by applying pressure in step (III) described below. Therefore, in step (I), the position where the laminate (X) and structure (Y) are adhered is determined as an application area depending on the shape of the desired bonded body, and the liquid (W) is applied to this application area. In the embodiment shown in Figures 2 to 8, an application area in the form shown in Figure 2 is provided to ultimately produce the three-sided pouch (three-sided bag) shown in Figure 9.

In step (I), the coated area is 1 to 50 area% of the total area (100% by mass) of the adhesive layer (A). If the area of the coated area is outside this range, the shape of the resulting adhesive body will be limited. The coated area can be selected appropriately depending on the shape of the resulting adhesive body; for example, if used as a packaging container, the shape of the packaging container. The coated area is preferably 3 area% or more, more preferably 5 area% or more, and even more preferably 10 area% or more, and preferably 45 area% or less, more preferably 40 area% or less.

The coating amount of liquid (W) in the coating area is preferably 10 g/ ^m2 or more, more preferably 12 g/ ^m2 or more, and preferably 30 g/ ^m2 or more or less, more preferably 25 g/ ^m2 or less, and even more preferably 20 g/ ^m2 or less. When the coating amount of liquid (W) in the coating area is equal to or more than the above-mentioned lower limit, the adhesive strength is easily increased and the occurrence of unevenness in the adhesive joint is easily suppressed. Furthermore, when the coating amount of liquid (W) in the coating area is equal to or less than the above-mentioned upper limit, the blocking property is easily increased and the occurrence of wrinkles in the adhesive joint is easily suppressed. Note that the adhesive joint means the part of the laminate where the adhesive layer (A) is bonded.

The liquid (W) is not particularly limited as long as it can adhere the adhesive layer (A) by application and pressure, and can be appropriately selected depending on the composition of the adhesive layer (A). Examples of components constituting the liquid (W) include water; alcohol-based solvents such as methanol, ethanol, propanol, and butanol; ester-based solvents such as methyl acetate and ethyl acetate; aromatic hydrocarbon-based solvents such as benzene, toluene, and xylene; nitrile-based solvents such as acetonitrile; ketone-based solvents such as acetone, methyl ethyl ketone, cyclopentanone, and cyclohexanone; ether-based solvents such as tetrahydrofuran and dimethoxyethane; amide-based solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; chlorine-containing solvents such as chloroform and chlorobenzene; polyvinyl alcohol-based resins such as polyvinyl alcohol; gelatin, xanthan gum, carrageenan, guar gum, sodium carboxymethylcellulose, and pectin. These components can be used alone or in combination. Among these, from the viewpoint of easily increasing adhesive strength, the liquid (W) preferably contains at least one selected from water, an alcohol-based solvent, a polyvinyl alcohol-based resin, gelatin, xanthan gum, carrageenan, guar gum , sodium carboxymethylcellulose, and pectin, and more preferably contains at least one selected from water, an alcohol-based solvent, and a polyvinyl alcohol-based resin. In one embodiment of the present invention, the liquid (W) contains 50% by mass or more of water relative to the mass of the liquid (W), and further preferably contains at least one selected from an alcohol-based solvent, a polyvinyl alcohol-based resin, gelatin, xanthan gum, carrageenan, guar gum, sodium carboxymethylcellulose, and pectin, more preferably contains an alcohol-based solvent or a polyvinyl alcohol-based resin, and even more preferably contains a polyvinyl alcohol-based resin. In such an embodiment, adhesive strength is more easily increased. Note that, in this specification, the term "alcohol-based solvent" does not include polyvinyl alcohol-based resin.

When liquid (W) contains water, the water content in liquid (W) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may even be 100% by mass, relative to the mass of liquid (W). Furthermore, the water content in liquid (W) is preferably 99% by mass or less, more preferably 98% by mass or less, even more preferably 97% by mass or less, and particularly preferably 96% by mass or less. When the water content in liquid (W) is within the above range, it is easy to increase the adhesive strength with structure (Y) and the like, and to form an adhesive body (Z) with excellent adhesive strength.

The viscosity of liquid (W) is preferably 0.3 cP or more, more preferably 1.0 cP or more, even more preferably 1.5 cP or more, even more preferably 5 cP or more, particularly preferably 10 cP or more, especially more preferably 20 cP or more, and preferably 100 cP or less, more preferably 80 cP or less, and even more preferably 60 cP or less. When the viscosity of liquid (W) is at or above the above lower limit, it is easy to increase the adhesive strength and to suppress the occurrence of unevenness in the adhesive joint. Furthermore, when the viscosity of liquid (W) is at or below the above upper limit, it is easy to increase blocking resistance.

Methods for applying the liquid (W) to the coating area of the adhesive layer (A) include, for example, a method in which a water supply roll (R) is brought into contact with the coating area of the adhesive layer (A) to apply the liquid (W) (see Figure 2); a method in which the liquid (W) is applied to the coating area of the adhesive layer (A) using a slit coater; and a method in which the liquid (W) is sprayed onto the coating area of the adhesive layer (A).

By using a method in which the liquid (W) is applied by bringing a water supply roll (R) into contact with the application area of the adhesive layer (A), the liquid (W) can be applied uniformly to the application area. In this method, it is preferable to apply the liquid (W) while replenishing the water supply roll (R). As a method for replenishing the liquid (W), from the viewpoint of easily improving production efficiency, a method in which the water supply roll (R) is immersed in the liquid (W) to replenishing the liquid (W) or a method in which the liquid (W) is reinforced from the inside of the water supply roll (R) is preferable.

The method of dipping the water supply roll (R) in the liquid (W) to replenish it may be a method using the water supply roll 7a and tray 15 shown in Figure 10, in which liquid 8 is placed in the tray 15 beforehand, and then dipping the water supply roll 7a in the liquid 8 and replenishing the liquid 8 to the sponge portion 6a while rotating. In the embodiment shown in Figure 2, the water supply roll 7a may be rotated while replenishing the liquid 8 from the tray 15 and applying it to the application area. In this case, the laminate 1a moves while contacting the upper part of the water supply roll 7a.

A method for reinforcing the liquid (W) from inside the water supply roll (R) may be to supply the liquid (W) to the inside of the water supply roll 7b shown in Figure 12 and replenish the liquid 8 in the sponge portion 6a. More specifically, the water supply roll 7b is a metal roll 5b with a sponge portion 6a attached to the outer periphery. The metal roll 5b is a hollow roll with one side closed and multiple holes 16 formed so as to contact the inside of the sponge portion 6a. Alternatively, the liquid (W) may be introduced into the water supply roll 7b and replenished as it penetrates the sponge portion 6a through the holes 16. In the embodiment shown in Figure 2, if the water supply roll 7b is used instead of the water supply roll 7a, the liquid 8 may be applied to the coating area while the water supply roll 7b is rotating and replenishing the liquid 8 inside the water supply roll 7b. In this case, the laminate 1a moves while being in contact with the upper or lower part of the water supply roll 7b.

In the method of applying the liquid (W) to the application area of the adhesive layer (A) using a slit coater, the slit coater is not particularly limited as long as it is capable of applying the liquid (W) to the application area, and any conventional slit coater can be used.

In the method of spraying the liquid (W) onto the application area of the adhesive layer (A), for example, a sprayer may be used to spray the liquid (W) onto the application area. This method makes it easy to change the spray application position. In this specification, the term "application" includes spraying.

In step (I), two or more methods selected from the group consisting of a method of applying the liquid (W) by bringing a water supply roll (R) into contact with the application area of the adhesive layer (A); a method of applying the liquid (W) to the application area of the adhesive layer (A) using a slit coater; and a method of spraying the liquid (W) onto the application area of the adhesive layer (A) can be combined.

[Step (II)]
Step (II) is a step of superposing the adhesive layer (A) of the laminate (X) and the structure (Y).

Figure 3 is a schematic diagram showing an example of the process of overlapping the adhesive layer (A) of the laminate (X) and the structure (Y) in step (II). As shown in Figure 3, the adhesive layer 2a of the laminate 1a coated with the liquid 8 is overlapped with the adhesive layer 2a of the structure 9a so that they come into contact. In Figure 3, the structure (Y) is a laminate (X') including the adhesive layer (A). By overlapping the structures so that their adhesive layers 2a come into contact with each other, it is easy to improve adhesive strength, blocking resistance, and appearance characteristics. In the embodiment shown in Figure 3, the laminate 1a and the structure 9a identical to the laminate 1a are overlapped with their edges aligned, but the method of overlapping the laminate (X) and the structure (Y) can be selected appropriately depending on the shape of the resulting adhesive body or container. Furthermore, in step (II), it is sufficient that at least the adhesive layer (A) coated with liquid (W) and the structure (Y) overlap entirely or partially; for example, a layer other than the adhesive layer of the structure (Y) may overlap the adhesive layer (A).

In step (II), the laminate (X) may be laminated so that the adhesive layer (A) of the laminate (X) is in contact with any layer contained in the laminate (X') (e.g., the base layer (B), another layer, or the adhesive layer (A)). From the viewpoint of easily improving adhesive strength, blocking resistance, and appearance characteristics, it is preferable to laminate so that the adhesive layer (A) of the laminate (X) is in contact with the adhesive layer (A) of the laminate (X'), as described above.

[Process (III)]
Step (III) is a step of pressurizing the stacked laminate (X) and structure (Y) in a pressurizing region. In the production method of the present invention, the application of liquid (W) in step (I) and the pressurization in step (III) are performed in combination, so that an adhesive bond having excellent adhesive strength can be formed. The pressurized region is a region on the surface of the laminate (X) or structure (Y) where pressure is applied.

Figures 4 to 7 are schematic diagrams showing an example of the process of pressing the stacked laminate (X) and structure (Y) in the pressurizing region in step (III).

As shown in Figures 4 and 5, the stacked laminate 1a and structure 9a are pressed from the base layer 4a side of structure 9a along the MD direction of the coating area by a long hot plate 10. Next, the long hot plate 10 is removed, and as shown in Figures 6 and 7, pressure is applied from the base layer 4a side of structure 9a along the TD direction of the coating area by a long hot plate 11. In this embodiment, pressure is applied so that the area ratio of the pressurized area is 0.8 to 1.2 times the area of the coating area, and the area ratio of the overlapping area between the pressurized area and the coated area is 0.8 to 1.2 times the area of the pressurized area. This results in an adhesive structure 12a in which the laminate 1a and structure 9a are bonded at the overlapping portion between the pressurized area and the coated area, i.e., the adhesive joint 13a, as shown in Figure 13. The adhesive structure 12a has a moisture content of 3 to 20% by mass in the adhesive layer of the laminate 1a, and is produced by combining coating in the coating region with pressure application in the pressure region, thereby achieving both excellent adhesive strength and excellent blocking resistance. The pressure region occupies 10 to 40% by area of the total area (100% by mass) of the adhesive layer 2a. The MD direction refers to the machine flow direction during production of the adhesive structure 12a, and the TD direction refers to the direction perpendicular to the machine flow direction during production of the adhesive structure 12a. The resulting adhesive structure 12a can be wound up on a take-up roll. When continuously produced using an unwinding roll, a transport roll, and a take-up roll, transport may be stopped between steps (II) and (III).

The pressure application by the long hot plate 10 and the long hot plate 11 can be carried out once or more, preferably twice or more, more preferably three times or more. By carrying out the pressure application twice or more, the adhesive strength can be easily increased. In the embodiment shown in Fig. 4 to Fig. 7, the pressure is applied by the long hot plate 10 along the MD direction, and then the pressure is applied by the long hot plate 11 along the TD direction. However, the pressure can be applied in the MD direction and the TD direction simultaneously by using, for example, a grid-shaped hot plate.
In the embodiments shown in Figures 4 to 7, pressure is applied from the base layer 4a side of the structure 9a, but the side (or surface) to which pressure is applied is not particularly limited, and pressure may be applied, for example, from the surface of the laminate 1a, i.e., the base layer 4a side of the laminate 1a.

In step (III), it is preferable to heat the pressurized region. By heating the pressurized region, the adhesive strength can be further improved. The temperature of the pressurized region is preferably 80°C or higher, more preferably 90°C or higher, even more preferably 120°C or higher, particularly preferably 150°C or higher, and preferably 200°C or lower. When the temperature of the pressurized region is above the above lower limit, the adhesive strength is easily improved, and when the temperature of the pressurized region is below the above upper limit, the occurrence of wrinkles in the adhesive joints is easily suppressed. The pressurizing pressure is preferably 0.1 kgf/ ^cm2 or higher, more preferably 0.5 kgf/ ^cm2 or higher, even more preferably 1.0 kgf/ ^cm2 or higher, and preferably 10 kgf/ ^cm2 or lower, more preferably 5 kgf/ ^cm2 or lower. When the pressurizing pressure is above the above lower limit, the adhesive strength is easily improved, and when the pressurizing pressure is below the above upper limit, the occurrence of wrinkles in the adhesive joints is easily suppressed. The pressurizing time is not particularly limited, but is preferably 0.05 seconds or more, more preferably 0.1 seconds or more, and preferably 60 seconds or less, more preferably 10 seconds or less, and even more preferably 5 seconds or less. When the pressurizing time is equal to or greater than the above-mentioned lower limit, the adhesive strength is likely to be improved, and when the pressurizing time is equal to or less than the above-mentioned upper limit, the occurrence of wrinkles in the adhesive joint is likely to be suppressed. When pressurizing is performed multiple times, the pressurizing pressure refers to the pressure for one pressurizing operation, and the pressurizing time refers to the total time for multiple pressurizing operations.

In step (III), the width (or length) of the pressure region in the lateral direction is preferably 5 to 30 mm, more preferably 8 to 20 mm. A width of the pressure region in the lateral direction within this range facilitates pressure application, which may be advantageous in terms of adhesive strength and wrinkle prevention. Furthermore, many commercially available hot plates are within this range, for example, 10 mm or 15 mm. Note that the width (or length) of the pressure region in the lateral direction can be adjusted by adjusting the width (or length) of the hot plate in the lateral direction to fall within the above range, for example, when using a hot plate for pressure application.

In step (III), the area of the pressurized region can be selected appropriately depending on the area of the coating region, etc., and is preferably at least 1 area%, more preferably at least 3 area%, even more preferably at least 5 area%, and particularly preferably at least 10 area%, relative to the total area (100% by mass) of the adhesive layer (A), and is preferably at most 45 area%, more preferably at most 40 area%. When the area of the pressurized region relative to the total area of the adhesive layer (A) is within the above range, adhesive strength and blocking resistance tend to be improved.

The area of the pressurized region is preferably 0.5 to 1.5 times the area of the coated region, and preferably includes the area where the pressurized region and the coated region overlap. The area of the pressurized region is preferably 0.7 to 1.3 times, and more preferably 0.8 to 1.2 times, the area of the coated region. When the area of the pressurized region relative to the coated region is within the above range, adhesive strength, blocking resistance, and appearance characteristics are likely to be improved.

The area of the overlapping portion between the pressurized region and the coated region is preferably 0.5 to 1.5 times, more preferably 0.7 to 1.3 times, and even more preferably 0.8 to 1.2 times the area of the pressurized region. When the area of the overlapping portion between the pressurized region and the coated region is within this range, adhesive strength and blocking resistance tend to be improved.

Pressure application in step (III) is preferably carried out for 1 to 20 seconds, more preferably 2 to 15 seconds, and even more preferably 3 to 10 seconds from the time liquid (W) is applied to the application area. This makes it easier to improve adhesive strength, blocking resistance, and appearance properties.

The method of applying pressure is not particularly limited, and examples include a method of applying pressure using a hot plate as shown in Figures 4 to 7; a method of applying pressure using a hot plate or the like in combination with ultrasound; and in the case of an adhesive body consisting of a main body (laminate) and a lid (structure), a method of applying pressure by replacing the atmosphere inside the container with a mixed gas containing nitrogen, carbon dioxide, or oxygen.

In the above embodiment, the adhesive portion 13a is formed by arranging two rectangular frames along the short side of the adhesive body 12a, but adhesive portions of various shapes can be formed by appropriately changing the shapes of the application area and pressure application area.

As described above, the manufacturing method of the present invention includes a method including steps (I) to (III) and a method including steps (II') and (III') instead of steps (II) and (III). The former method involves bonding the laminate (X) and the structure (Y), while the latter method involves folding and bonding the laminate (X) itself. For example, in the embodiment shown in Figures 2 to 8, the former method was used to form the bonded body 12a using the laminate 1a and the structure 9a (same as the laminate 1a), i.e., two laminates, while the latter method can form the bonded body 12a' using a single laminate. The bonded body 12a' is the same as the bonded body 12a except that one end is connected.

[Step (II')]
Step (II') is a step of folding the laminate (X) so that the adhesive layers (A) face each other or so that the adhesive layer (A) faces a layer other than the adhesive layer (A). The layer other than the adhesive layer (A) is not particularly limited as long as it is a layer other than the adhesive layer (A) contained in the laminate (X), and examples thereof include the base layer (B), the adhesive layer (C), and the other layer.

For example, the laminate 1a (Figure 3) to which the liquid 8 has been applied in step (I) can be folded so that the adhesive layers 2a are on the inside, allowing the adhesive layers 2a to be stacked so that they face each other.

[Process (III')]
Step (III') is a step of pressing the folded laminate (X) in the pressurizing region. For example, as described above, by pressing a laminate obtained by folding the laminate 1a in the pressurizing region, an adhered body 12a' can be formed in which the adhesive layers 2a of the laminate 1a are adhered to each other. The same pressurizing conditions as those in step (III) can be used for the pressurizing. The adhered body 12a' has a moisture content of 3 to 20 mass% in the adhesive layers 2a of the laminate 1a and is produced by a method that combines coating in the coating region and pressurizing in the pressurizing region, so that it can achieve both excellent adhesive strength and excellent blocking resistance.

Even in embodiments that include steps (I), (II'), and (III') [sometimes referred to as steps (I) to (III')], adhesive joints of various shapes can be formed by appropriately changing the shapes of the application area and pressure application area.

[Adhesive body and packaging container]
The adhesive bonded article (Z) obtained by the manufacturing method of the present invention is formed by bonding a laminate (X) or a laminate (X) and a structure (Y). Because the manufacturing method of the present invention includes steps (I) to (III) or steps (I) to (III'), the adhesive bonded article (Z) obtained has excellent adhesive strength and blocking resistance. Furthermore, in a preferred embodiment of the present invention, the adhesive bonded article (Z) also has excellent appearance characteristics and gas barrier properties. Therefore, the adhesive bonded article (Z) of the present invention can be suitably used as a material for packaging containers for food and the like.

The adhesive structure of the present invention has excellent adhesive strength. The adhesive strength of the bonded portion of the adhesive structure is preferably 100 g/15 mm or more, more preferably 150 g/15 mm or more, even more preferably 200 g/15 mm or more, even more preferably 250 g/15 mm or more, and particularly preferably 300 g/15 mm or more. There is no particular upper limit to the adhesive strength, but it is usually 1000 g/15 mm or less. The adhesive strength can be measured using a tensile tester at a tensile speed of 50 mm/min, an initial chuck distance of 50 mm, and T-peel mode after storing and regulating the humidity for 7 days at 23°C and 50% RH, and is the average of five measurements. It can be measured, for example, by the method described in the Examples.

There are no particular limitations on the uses of the adhesive, but the adhesive may be cut into pieces for use, or the adhesive may be used as is.

The present invention includes a method for manufacturing a packaging container using the adhesive (Z).

First, an example of how a packaging container is produced by cutting an adhesive bonded body is shown. Figure 8 is a schematic diagram showing an adhesive bonded body according to one embodiment of the present invention and the cutting lines for the adhesive bonded body. More specifically, Figure 8 shows adhesive bonded body 12a produced by the method shown in Figures 2 to 7. Since adhesive bonded body 12a forms adhesive sections in which two rectangular frames are arranged in the short direction of adhesive bonded body 12a, the three-sided pouch 14 shown in Figure 9 can be produced by cutting adhesive bonded body 12a along cutting planes that are moved perpendicular to the thickness direction along cutting lines 102 that run along the long and short directions of the adhesive sections.

Next, we will show how the adhesive bonded body (Z) can be used as a packaging container without modification. Figure 17 is a schematic cross-sectional view of adhesive bonded body 12b in one embodiment of the present invention. Adhesive bonded body 12b is obtained by applying liquid (W) to the flange portion (application area) of container-shaped laminate 1b, which has base layer 4b, adhesive layer 3b, and adhesive layer 2b in this order; overlapping container-shaped laminate 1b and structure 9b so that adhesive layer 2b of laminate 1b contacts adhesive layer 2a of structure 9b (identical to laminate 1a); and then pressing the overlapped container-shaped laminate 1b and structure 9b from the base layer 4a side of structure 9b in the pressure area corresponding to the flange portion. In this embodiment, adhesive bonded body 12b can be used as a packaging container without modification.

The shape of the packaging container is not particularly limited, but it is preferable that the packaging container be a flat pouch, standing pouch, gusset pouch, twin pouch, spout pouch, thermoformed container, or injection molded container.

The present invention will be described in detail below using examples, but the present invention is not limited to these embodiments.

<Test Method>
(1) Moisture Content of Adhesive Layer After storing the laminate under the conditions described in the Examples and Comparative Examples, the moisture content of the adhesive layer included in the laminate obtained in the Examples and Comparative Examples was measured using an "UMAREX Moisture Finder Compact" manufactured by UMAREX GmbH & Co.

(2) Oxygen transmission rate (OTR)
The adhesive layers used in the examples and comparative examples were stored at 23°C and 50% RH for two weeks to condition the humidity, and then attached to an oxygen transmission rate measuring device, and the oxygen transmission rate (mL.20µm/( ^m2.day.atm )) was measured in accordance with the method described in JIS K7126 (constant pressure method). The measurement conditions were as follows:
Equipment: Modern Control "MOCON OX-TRAN2/20"
Temperature: 23℃
Humidity on the oxygen supply side and carrier gas side: 50% RH
Oxygen pressure: 1.0 atm
Carrier gas pressure: 1.0 atm

(3) Appearance characteristics (wrinkles at adhesive joints)
The adhesive structures obtained in the Examples and Comparative Examples were visually inspected for appearance after storage at 23°C and 50% RH for 7 days, and the occurrence of wrinkles was evaluated according to the following criteria: A or B can be evaluated as having good appearance characteristics.
A: No wrinkles were observed and no abnormalities were found in the appearance. B: Some wrinkles were observed, but not to a level that would cause problems as a product. C: Wrinkles were observed and the appearance was judged to be abnormal.

(4) Appearance characteristics (deadsmosomes)
The adhesive structures obtained in the Examples and Comparative Examples were visually inspected for appearance after storage at 23°C and 50% RH for 7 days, and the occurrence of adhesive spots (seal spots) was evaluated according to the following criteria: A or B can be evaluated as having good appearance characteristics.
A: There were no adhesion spots and no abnormalities were observed in appearance. B: There were some adhesion spots, but the product was still adhered and not at a level that would cause problems as a product. C: There were adhesion spots, but the product was still adhered and not at a level that would cause problems as a product. D: Adhesion spots occurred and the product was judged to have an abnormal appearance.

(5) Adhesive Strength The adhesive portions of the packaging containers obtained in the Examples and Comparative Examples were cut into 15 mm x 150 mm strips and stored at 23°C and 50% RH for 7 days to condition the humidity. Next, the adhesive strength of the adhesive portions of the adhesive layer was measured using a tensile tester (Instron Corporation, Instron 3367) at a speed of 50 mm/min, an initial chuck distance of 50 mm, and a T-peel mode. The same test was performed five times, and the average value was used as the adhesive strength value and evaluated according to the following criteria.
<Adhesive strength judgment criteria>
Judgment: Criteria A: 300g/15mm or more B: 200g/15mm or more and less than 300g/15mm C: 100g/15mm or more and less than 200g/15mm D: Less than 100g/15mm

(6) Blocking Resistance A weight of 1 kg was placed on the entire packaging container obtained in the Examples and Comparative Examples, and after storing at 23°C and 50% RH for 7 days, the ease of opening the opening was evaluated according to the following criteria. If it was rated A or B, it could be evaluated as having good blocking resistance.
A: It was possible to open it easily. B: There was some adhesion between the laminate and the structure outside the pressurized area, but it was possible to open it. C: There was adhesion between the laminate and the structure outside the pressurized area, and it was not possible to open it.

(7) Thickness Measurement The adhesive structures obtained in the Examples and Comparative Examples were cut in the TD direction (width direction) using a microtome to prepare cross sections in the thickness direction. Subsequently, using an optical microscope, the average thickness of the adhesive layer, base layer, and adhesive layer at five arbitrarily selected points was taken as the average thickness of each layer.

[Example 1]
<Preparation of Laminate and Structure>
A laminate 1a having the layer structure shown in FIG. 1 was obtained as follows.
A gas barrier film (manufactured by Kuraray Co., Ltd., trade name "Plantic® HP 50μm", thickness: 50μm, oxygen permeability: 5.2cc.20μm/( ^m².day.atm )) was used as the adhesive layer 2a, and kraft paper (basis weight 100g/ ^m² , thickness 120μm) was used as the substrate layer 4a. A two-component urethane adhesive (manufactured by Mitsui Chemicals, Inc., "Takelac™ A-385"/"Takenate™ A-50") was applied to one side of the adhesive layer 2a at a basis weight of 2.5g/ ^m² solids, and then the substrate layer 4a was laminated by dry lamination to obtain a laminate 1a. The resulting laminate 1a was stored at 20°C and 65% RH for one week, and the moisture content of the adhesive layer 2a in the laminate 1a was measured by the above method and found to be 12.4% by mass.

<Production of Adhesive Body>
The obtained laminate 1a was wound around a winding roll. Next, the laminate 1a was unwound from the winding roll, and an adhesive bonded body 12a was produced according to the following steps, and then wound around a winding roll.
Specifically, a water supply roll 7a was prepared by attaching a sponge portion 6a cut from a PVA sponge roller manufactured by AION Corporation to a metal roll 5a so that the sponge portion 6a matched the coating area of the adhesive layer 2a . Next, a solution 8 was prepared by dissolving polyvinyl alcohol (POVAL 22-88 manufactured by Kuraray Co., Ltd.) in ion-exchange water at a concentration of 5% by mass, and the solution was placed in a tray 15 (see FIG. 10 ). Next, while the sponge portion 6a of the metal roll 5a was soaked in the solution 8, the distance between the water supply roll 7a and the adhesive layer 2a was adjusted, and the solution was applied to the coating area of the adhesive layer 2a at a coating amount of 12 g/ ^m2 (see FIG. 2 ). The coating area covered 37% of the total area of the adhesive layer 2a.
The laminate 1a and the structure 9a were stacked so that the adhesive layer 2a of the laminate 1a coated with the liquid 8 contacted the adhesive layer 2a of the structure 9a (see FIG. 3 ), and the stacked laminate 1a and structure 9a were pressed in the pressurized region (see FIGS. 4 to 7 ). In this pressurizing step, long hot plates 10 and 11, each 15 mm wide in the short direction, were used. Pressurization was performed so that the area ratio of the pressurized region to the area of the coated region was 1.0, and the area ratio of the overlapping area between the pressurized region and the coated region was 1.0. More specifically, the long hot plate 10 was first placed along the MD of the coated region, and pressurization was performed for 0.5 seconds under conditions of a pressurizing section temperature of 170°C and a pressurizing pressure of 2 kgf/ ^cm² (see FIGS. 4 and 5 ). This process was repeated three times. Next, the long hot plate 11 was placed along the TD of the coated region, and pressurization was performed for 0.5 seconds under the same conditions (see FIGS. 6 and 7 ). This process was repeated three times. The first pressurization was carried out 5 seconds after the liquid 8 was applied to the application area.
In this way, a bonded body 12a was obtained. In the bonded body 12a, the laminate 1a and the structure 9a were bonded to each other at a bonding portion 13a corresponding to the overlapping portion of the applied region and the pressurized region.

<Manufacturing of packaging containers (pouches)>
The adhesive portion 13a of the obtained adhesive body 12a was cut along cutting lines 102 extending in the longitudinal and lateral directions, which were moved perpendicular to the thickness direction (see FIG. 8 ). In this way, a three-sided pouch 14, which was an adhesive body having both ends and a bottom sealed and measuring 15 cm in length and 10 cm in width, was obtained (see FIG. 9 ).

[Examples 2 to 18 and Comparative Examples 1 to 3]
A laminate 1a, an adhesive body 12a, and a three-sided pouch 14 were obtained in the same manner as in Example 1, except that the conditions were changed as shown in Table 1. In Examples 15, 16, and Comparative Example 3, an ethylene-vinyl alcohol copolymer sheet (manufactured by Kuraray Co., Ltd., trade name "EVAL F101B", ethylene unit content 32 mol%) was used as the material for forming the adhesive layer.

[Comparative Example 4]
11 was used instead of the water supply roll 7a in the coating step, and the entire surface of the adhesive layer 2a of the laminate 1a was used as the coating area, and liquid 8 was applied to this coating area. Except for this, laminate 1a, adhesive body, and three-sided pouch were obtained in the same manner as in Example 1. Water supply roll 7c was prepared by attaching sponge part 6b cut out from a "PVA sponge roller" manufactured by AION Co., Ltd. to metal roll 5a so as to fit the coating area.

[Comparative Example 5]
A laminate 1a, an adhesive body 12a and a three-sided pouch 14 were obtained in the same manner as in Example 1, except that the liquid (W) was not applied.

[Example 19]
A laminate 1a, an adhesive body 12a, and a three-sided pouch 14 were obtained in the same manner as in Example 1, except that a water supply roll 7b shown in Figure 12 was used instead of the water supply roll 7a and the tray 15 in the coating step. The water supply roll 7b was a metal roll 5b with a sponge portion 6a attached. The metal roll 5b was a hollow roll with one side closed, and had multiple holes 16 formed so as to contact the inside of the sponge portion 6a. In the coating step, the liquid 8 was introduced into the water supply roll 7b and applied to the coating area on the surface of the adhesive layer 2a of the laminate 1a while being allowed to penetrate into the sponge portion 6a through the holes 16.

[Example 20]
A laminate 1a, an adhesive body 12a and a three-sided pouch 14 were obtained in the same manner as in Example 1, except that in the coating process, a slot coater was used to apply the liquid 8 to the coating area instead of the water supply roll 7a.

[Example 21]
A laminate 1a, an adhesive body 12a and a three-sided pouch 14 were obtained in the same manner as in Example 1, except that in the coating step, the liquid 8 was sprayed onto the coating area using a dispenser device.

[Example 22]
In the coating process, the liquid 8 was applied to the coating area using a slot coater in the MD direction and a water supply roll 7a in the TD direction, but the same method as in Example 1 was used to obtain a laminate 1a, an adhesive body 12a, and a three-sided pouch 14.

[Example 23]
A laminate, an adhesive body, and a gusset pouch were obtained in the same manner as in Example 1, except that the coating area in step (I) (coating step), the pressurizing area in step (III) (pressurizing step), and the overlapping method and cutting locations in step (III) (overlapping step) were adjusted so as to obtain the shape of the gusset pouch shown in FIG. 13 .

[Example 24]
A laminate, an adhesive body, and a standing pouch were obtained in the same manner as in Example 1, except that the coating area in step (I) (coating step), the pressurizing area in step (III) (pressurizing step), and the overlapping method and cutting locations in step (III) (overlapping step) were adjusted so as to obtain the shape of the standing pouch shown in FIG. 14 .

[Example 25]
A laminate, an adhesive body, and a twin pouch were obtained in the same manner as in Example 1, except that the coating area in step (I) (coating step), the pressurizing area in step (III) (pressurizing step), and the overlapping method and cutting locations in step (III) (overlapping step) were adjusted so as to obtain the twin pouch shape shown in FIG. 15 .

[Example 26]
A laminate, an adhesive body, and a spout pouch were obtained in the same manner as in Example 1, except that the coating area in step (I) (coating step), the pressurizing area in step (III) (pressurizing step), and the overlapping method and cutting locations in step (III) (overlapping step) were adjusted so as to obtain the shape of the spout pouch shown in FIG. 16 .

[Example 27]
<Preparation of Laminate and Structure>
A single-layer polypropylene sheet (thickness: 600 μm) was obtained using polypropylene (PP, trade name "Novatec™ PP EA7AD") by the following method/conditions, and this was used as a substrate layer. The film-forming equipment had a temperature-controllable take-up roll following an extruder with a film-forming die, and the obtained polypropylene sheet was wound up by a winder.
PP extruder: 40 mmφ extruder PP extrusion temperature feeding section/compression section/metering section/die = 150°C/200°C/210°C/220°C
Die: 300 mm wide coat hanger die take-up roll temperature: 80°C
A two-component urethane adhesive (Takelac™ A-385/Takenate™ A-50, manufactured by Mitsui Chemicals, Inc.) was applied to one side of a polypropylene sheet at a basis weight of 2.5 g/ ^m² solids, and then an ethylene-vinyl alcohol copolymer sheet (EF-F 15 μm, manufactured by Kuraray Co., Ltd.) was laminated as an adhesive layer by dry lamination to obtain a laminate having a polypropylene sheet (substrate layer), an adhesive layer, and an ethylene-vinyl alcohol copolymer sheet (adhesive layer) in this order. Furthermore, the laminate 1a obtained in Example 1 was used as a structure (referred to as structure 9b).

<Production of adhesive body and packaging container>
A packaging container, which is an adhesive body shown in FIG. 17 (schematic cross-sectional view), was produced as follows.
The laminate obtained above was thermoformed (compressed air: 5 kg/ ^cm2 , plug temperature: 150°C, mold temperature: 70°C) into a container shape (12 cm length x 9 cm width x 3 cm height) using a thermoforming machine (manufactured by Asano Seisakusho) at a sheet temperature of 150°C to obtain a container-shaped laminate 1b (a laminate having a base layer 4b, an adhesive layer 3b, and an adhesive layer 2b in this order) with a flange width of 15 mm. The obtained container-shaped laminate 1b was stored at 20°C and 65% RH for one week, and the moisture content of the adhesive layer 2b in the container-shaped laminate 1b was measured using the above method and found to be 12.4%. Next, the flange surface of the container-shaped laminate 1b was used as the coating area, and a solution of water/methanol = 60/40 (mass%) was applied to the coating area using the water supply roll 7c used in Comparative Example 4 so that the coating amount was 12 g/ ^m2 . The coating area was 30.7% of the total area of the adhesive layer 2b of the container-shaped laminate 1b. Next, using a "Tray sealer T200" manufactured by MULTIVAC, the laminate 1b and the structure 9b were overlapped so that the adhesive layer 2b of the laminate 1b coated with the liquid and the adhesive layer 2a of the structure 9b were in contact, and the container was evacuated and then filled with nitrogen. The overlapping laminate 1b and the structure 9b were pressed in the pressurized region (flange portion) using a hot plate at a pressure of 2 kgf/cm ² and a pressure temperature of 170 ° C. The pressure was applied so that the area ratio of the pressurized region to the area of the coated region was 1.0, and the area ratio of the overlapping area of the coated region and the pressurized region was 1.0 to the area of the pressurized region.
In this way, a packaging container was obtained which was an adhesive body 12b in which the container-shaped laminate (tray body) 1b and the structural body (lid) 9b were adhered to each other at the adhesive portion 13b.

The results of measuring the moisture content (mass%) and oxygen transmission rate (OTR, mL.20 μm/(m ² .day.atm)) of the adhesive layer in the laminates obtained in Examples 1 to 27 and Comparative Examples 1 to 5, as well as the evaluation results of the appearance characteristics of the adhesive joints of the adhesive bodies (wrinkles and spots in the adhesive joints), and the adhesive strength and blocking resistance of the packaging containers (pouches), are shown in Table 1. Table 1 also shows the material and thickness (μm) of the adhesive layer, the type and viscosity (cp) of the liquid used, the material and thickness (μm) of the structure, the application method in the application step, the amount applied and the area ratio of the applied region (area %), the pressurization temperature (°C) in the pressurization step, and the shape of the container.

As shown in Table 1, the packaging containers obtained in Comparative Examples 1 and 4 had adhesion at unintended locations, making it impossible to open the openings, and were confirmed to have poor blocking resistance. Furthermore, the packaging containers obtained in Comparative Examples 2, 3, and 5 had adhesive strengths of less than 100 g/15 mm, confirming poor adhesive strength. In contrast, the packaging containers obtained in Examples 1 to 27 were confirmed to have superior blocking resistance compared to Comparative Examples 1 and 4, and superior adhesive strength compared to Comparative Examples 2, 3, and 5.
Therefore, it was found that the adhesive body of the present invention can form a packaging container having excellent adhesive strength and blocking resistance.

1a... Laminate, 1b... Container-shaped laminate, 2a, 2b... Adhesive layer, 3a, 3b... Adhesive layer, 4a, 4b... Base material layer, 5a, 5b... Metal roll, 6a, 6b... Sponge part, 7a, 7b, 7c... Water supply roller 8... Liquid, 9a, 9b... Structure, 10, 11... Long hot plate, 12a, 12b... Adhesive body, 13a, 13b... Adhesive part, 14... Three-sided bag, 15... Receiver, 16... Hole, 101... Rotation direction, 102... Cutting line

Claims (20)

A method for producing a bonded body (Z) obtained by bonding a laminate (X) including an adhesive layer (A) and a structure (Y), comprising:
A step (I) of applying the liquid (W) to a coating area of 1 to 45 area % of the total area of the adhesive layer (A);
a step (II) of superposing the adhesive layer (A) of the laminate (X) on the structure (Y); and a step (III) of pressing the superposed laminate (X) and structure (Y) in a pressure region.
Including,
In the step (I), the water content of the adhesive layer (A) before the application of the liquid (W) is 3 to 20% by mass,
the adhesive layer (A) is a film or sheet containing modified starch (a) as a main component or a film or sheet containing ethylene-vinyl alcohol copolymer (c) as a main component ;
The adhesive strength of the adhesive joint of the adhesive body (Z) is 100 g/15 mm or more,
The amount of liquid (W) applied to the application area is 5 to 35 g/m ² ;
When the adhesive layer (A) is a film or sheet containing modified starch (a) as a main component, the water content of the adhesive layer (A) before applying the liquid (W) in the step (I) is 6 to 19% by mass,
When the adhesive layer (A) is a film or sheet containing the ethylene-vinyl alcohol copolymer (c) as a main component, the water content of the adhesive layer (A) before applying the liquid (W) in the step (I) is 3.5 to 12.4 mass%.
method. A method for producing a bonded body (Z) obtained by bonding a laminate (X) including an adhesive layer (A), comprising:
A step (I) of applying the liquid (W) to a coating area of 1 to 45 area % of the total area of the adhesive layer (A);
a step (II') of folding the laminate (X) so that the adhesive layers (A) face each other or the adhesive layers (A) face a layer other than the adhesive layer (A); and a step (III') of pressing the folded laminate (X) in a pressurizing region.
Including,
In the step (I), the water content of the adhesive layer (A) before the application of the liquid (W) is 3 to 20% by mass,
the adhesive layer (A) is a film or sheet containing modified starch (a) as a main component or a film or sheet containing ethylene-vinyl alcohol copolymer (c) as a main component ;
The adhesive strength of the adhesive joint of the adhesive body (Z) is 100 g/15 mm or more,
The amount of liquid (W) applied to the application area is 5 to 35 g/m ² ;
When the adhesive layer (A) is a film or sheet containing modified starch (a) as a main component, the water content of the adhesive layer (A) before applying the liquid (W) in the step (I) is 6 to 19% by mass,
When the adhesive layer (A) is a film or sheet containing the ethylene-vinyl alcohol copolymer (c) as a main component, the water content of the adhesive layer (A) before applying the liquid (W) in the step (I) is 3.5 to 12.4 mass%.
method. 3. The method according to claim 1, wherein the adhesive layer (A) has an oxygen permeability of 0.01 to 10 mL.20 μm/(m ² .day.atm). The method of any one of claims 1 to 3, wherein the laminate (X) further contains paper (C). The method of any one of claims 1 to 4, wherein the pressure application region is heated in steps (III) and (III'). The method according to any one of claims 1 to 5, wherein in step (I), the coating amount of the liquid (W) in the coating area is 10 to 30 g/ ^m2 . The method of any one of claims 1 to 6, wherein in step (I), liquid (W) contains 50% by mass or more of water and has a viscosity of 0.3 to 100 cP. The method of any one of claims 1 to 7, wherein in step (I), the liquid (W) is applied by bringing a water supply roll (R) into contact with the application area of the adhesive layer (A). The method of any one of claims 1 to 8, wherein in step (I), the liquid (W) is applied to the application area of the adhesive layer (A) using a slit coater. The method of any one of claims 1 to 9, wherein in step (I), liquid (W) is sprayed onto the application area of adhesive layer (A). The method of any one of claims 1 to 7, wherein step (I) combines two or more methods selected from the group consisting of a method of applying the liquid (W) by bringing a water supply roll (R) into contact with the application area of the adhesive layer (A); a method of applying the liquid (W) to the application area of the adhesive layer (A) using a slit coater; and a method of spraying the liquid (W) onto the application area of the adhesive layer (A). The method of any one of claims 1 to 11, wherein the pressure zone is heated to 80 to 200°C in steps (III) and (III'). 13. The method according to any one of claims 1 to 12, wherein in step (I), the liquid (W) contains at least one selected from the group consisting of an alcohol-based solvent, a polyvinyl alcohol-based resin, gelatin, xanthan gum, carrageenan, guar gum , sodium carboxymethylcellulose, and pectin. The method of any one of claims 1 and 3 to 13, wherein the structure (Y) is a laminate (X') including an adhesive layer (A) or a laminate (Q) not including an adhesive layer (A). The method according to claim 14, wherein in step (II), the adhesive layer (A) of the laminate (X) and the adhesive layer (A) of the laminate (X') are laminated so as to be in contact with each other. The method according to any one of claims 1 to 15 , wherein in steps (III) and (III'), the width of the pressurized region in the lateral direction is 5 to 30 mm. 17. The method according to claim 1, wherein in steps (III) and (III'), the area of the pressurized region is 0.5 to 1.5 times the area of the coated region, and includes an overlapping portion between the pressurized region and the coated region. The method according to any one of claims 1 to 17 , wherein the area of the overlapping portion between the pressurized region and the applied region is 0.5 to 2.0 times the area of the pressurized region. A method for producing a packaging container using an adhesive (Z) obtained by the method according to any one of claims 1 to 18 . 20. The method of claim 19 , wherein the packaging container is a flat pouch, a stand-up pouch, a gusset pouch, a twin pouch, a spout pouch, a thermoformed container, or an injection molded container.