WO2021251124A1

WO2021251124A1 - Packaging body

Info

Publication number: WO2021251124A1
Application number: PCT/JP2021/019721
Authority: WO
Inventors: 満美子藤井; 智宮丸
Original assignee: 株式会社Moresco
Priority date: 2020-06-11
Filing date: 2021-05-25
Publication date: 2021-12-16
Also published as: JPWO2021251124A1; JP7402335B2

Abstract

One aspect of the present invention relates to a packaging body comprisingcat least a paper substrate and a hot melt adhesive, wherein the packaging body is characterized in that the hot melt adhesive is obtained by a production method that includes kneading a liquid material for a hot melt adhesive, introducing a liquid comprising water and/or alcohol in a quantity of 0.03 mass parts or more per 100 mass parts of the material for a hot melt adhesive into a heating/kneading machine during said kneading or subsequent thereto, and degassing while heating and stirring or dispersing so that the material for a hot melt adhesive and the liquid come into contact.

Description

Package

The present invention relates to a package, and more particularly to a package in which a paper base material is fixed by a hot melt adhesive.

Ethylene vinyl acetate (EVA) -based hot melt adhesives are made of paper substrates and are suitable for high-speed workability and a wide range of adherends in fields such as packaging and bookbinding for foods, beverages, children's toys, etc. It is often used because it has excellent adhesiveness and economy, and can greatly contribute to improving productivity.

On the other hand, the EVA hot melt adhesive has a peculiar odor, and there is a concern that the odor may be transferred from the packaging container or the like using the hot melt adhesive to the food. Further, at the manufacturing site, heating the hot melt adhesive generates a large amount of bad odor, resulting in a poor environment, and there is a strong demand for a low odor of the EVA hot melt adhesive.

The cause of the odor is vinyl acetate, which is an unreacted monomer contained in the ethylene-vinyl acetate copolymer, which is the main component of the EVA hot melt adhesive, and the acetoxy group is decomposed (desorbed) at high temperatures during manufacturing and coating. Acetate generated by acetic acid), vinyl acetate monomers generated by depolymerization, low polymerization compounds, and the like.

These odor-causing substances are always generated by heating to a high temperature when producing a hot-melt adhesive even if a highly purified ethylene-vinyl acetate copolymer is used, so they should be avoided with EVA-based hot-melt adhesives. It is a problem that cannot be done. In particular, in the packaging of foods, confectionery, and children's toys, the use of EVA-based hot melt adhesives, which have a unique odor (mainly acetic acid odor), may cause the image of rotting of foods and confectionery, which is a major problem. It becomes. Therefore, it is required to reduce the odor component in the packaging for packaging for these products.

As a method for reducing the odorous component contained in the hot melt adhesive, for example, when supplying polyolefin to a single-screw or twin-screw extruder, a method of supplying 0.15% by weight or more of water has been used. (Patent Document 1) and a method of adding a specific aldehyde scavenger (Patent Document 2) have been reported.

However, in the method described in Patent Document 1, the contact time between water and the hot melt adhesive raw material is short, and a sufficient deodorizing effect is not obtained. Further, the method described in Patent Document 2 has an odor peculiar to aminobenzamide used as an aldehyde scavenger, and the deodorizing effect is also limited because the amount of the additive added is limited.

In addition, an alternative to ethyl acrylate copolymer, which has a structure and physical properties similar to that of ethylene-vinyl acetate copolymer, has been proposed, but it has a peculiar odor different from acetic acid and vinyl acetate monomer, and has a variety of hot melts. There are few varieties to meet the design of adhesives, the degree of freedom is poor, and the price is high.

Japanese Unexamined Patent Publication No. 10-193436 Japanese Unexamined Patent Publication No. 2017-125181

An object of the present invention is to solve the above-mentioned problems. That is, the present invention has a low odor even though a hot melt adhesive showing excellent adhesive performance is used in a package for products such as foods in which the odor of the adhesive (particularly the odor of acetic acid) is a major problem. The purpose is to provide a packaging body that is.

As a result of diligent research to solve the above problems, the present inventors have found that the above object can be achieved by the following configuration, and have completed the present invention by further studies based on this finding.

That is, the package according to one aspect of the present invention is a package in which a paper base material is fixed by a hot melt adhesive, and the hot melt adhesive kneads a liquid material for hot melt adhesive. After a period of or kneading, a liquid consisting of at least one of water and alcohol is introduced into a heat kneader in an amount of 0.03 part by mass or more with respect to 100 parts by mass of the hot melt adhesive material, and the hot melt is used. It is a hot melt adhesive obtained by a manufacturing method including degassing while heating, stirring or dispersing so that the adhesive material and the liquid are in contact with each other, and the residual acetic acid amount is 17 ppb or less. It is characterized by.

The package according to the present invention is a package in which the paper base material is fixed by a hot melt adhesive. In the package of the present invention, the hot melt adhesive used for fixing the paper substrate is at least one of water and alcohol in a heat kneader during or after kneading the liquid hot melt adhesive material. A liquid consisting of the above is introduced in an amount of 0.03 part by mass or more with respect to 100 parts by mass of the hot melt adhesive material, and while heating, stirring or dispersing so that the hot melt adhesive material and the liquid are in contact with each other. , A hot melt adhesive obtained by a manufacturing method comprising degassing. The hot melt adhesive is characterized by having a low odor while maintaining excellent performance as an adhesive. As a result, the residual acetic acid amount of the package of the present invention is 17 ppb or less, and the odor is suppressed as compared with the package using the hot melt adhesive conventionally used.

With such a configuration, it is possible to provide a package having a low odor even though the paper base material is fixed by using a hot melt adhesive showing excellent adhesive performance. Therefore, according to the present invention, it is possible to reduce the odor of various packages by a technique capable of dealing with many hot melt adhesives without limiting the performance of various conventional hot melt adhesives. In addition, since it is not necessary to use a special material, it leads to cost reduction.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited thereto.

First, the hot melt adhesive will be explained. The hot-melt adhesive that can be used in this embodiment is not limited, but in particular, in this embodiment, since it is possible to suppress the acetic acid odor, the EVA-based adhesive is excellent in workability, adhesiveness, economy, and the like. It is preferable to use a hot melt adhesive.

As the hot melt adhesive material for such an adhesive, the base resin, tackifier, wax, and other additives conventionally used for the hot melt adhesive can be used without particular limitation. According to this embodiment, there is an advantage that a package having a low odor can be provided regardless of which EVA hot melt adhesive material is used.

As a specific material, as the base resin, for example, a thermoplastic resin used as a component constituting an EVA hot melt adhesive can be used without particular limitation.

The EVA-based thermoplastic resin is not particularly limited as long as it is used as an EVA-based thermoplastic resin in a hot melt adhesive, and examples thereof include a copolymer synthesized from ethylene and vinyl acetate. Be done.

The EVA-based base resin as described above may be used individually by 1 type, or may be used in combination of 2 or more types.

Further, in the present embodiment, a biomass-based hot melt adhesive can be used in addition to the above. The biomass-based hot melt adhesive is an adhesive containing a biomass-derived raw material, and examples thereof include an adhesive containing a plant-derived resin such as pine fat.

As for the tackifier, a synthetic resin-based tackifier generally used for hot melt adhesives, for example, aromatic, aliphatic, alicyclic petroleum resin, or natural resin-based tackifiers. The agent, its hydrogen additive, and the like can be used without particular limitation. For example, natural resins used as raw materials for biomass include natural rosin, modified rosin, hydrocarbon rosin, glycerol ester of natural rosin, glycerol ester of modified rosin, pentaerythritol ester of natural rosin, pentaerythritol ester of modified rosin, and water. Pentaerythritol ester of rosin, copolymer of natural terpen, three-dimensional polymer of natural terpen, hydrocarbon derivative of hydrogenated terpen copolymer, polyterpene resin, hydride of phenol-based modified terpene resin, aliphatic petroleum in synthetic resin Hydrocarbon resin, hydrogenated derivative of aliphatic petroleum hydrocarbon resin, aromatic petroleum hydrocarbon resin, hydrogenated derivative of aromatic petroleum hydrocarbon resin, cyclic aliphatic petroleum hydrocarbon resin, hydrogen of cyclic aliphatic petroleum hydrocarbon resin Hydrocarbon derivatives can be exemplified. The tackifiers as described above may be used individually by 1 type, or may be used in combination of 2 or more types.

The wax is not particularly limited as long as it is a wax contained in the hot melt adhesive. Examples of the wax include synthetic wax, petroleum wax, natural wax and the like. Examples of the synthetic wax include polyolefin waxes such as Fischer-Tropsch wax, polyethylene wax and polypropylene wax. Examples of the petroleum wax include paraffin wax, microcrystalline wax, petratum and the like. Examples of the natural wax include Montan wax. Examples of the natural wax used as a raw material for biomass include wood wax, carbana wax, beeswax, and castor wax. As these waxes, the waxes exemplified above may be used alone, or two or more kinds may be used in combination.

In addition, as additives, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, fillers, surfactants, coupling agents, colorants, antistatic agents, flame retardants, plasticizers, etc. are used. May be good.

For example, examples of the antioxidant include a phenol-based antioxidant, an organic sulfur-based antioxidant, and the like. Examples of the phenolic antioxidant include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 2 -Tert-Butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenylacrylate, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxy) Phenyl) propionate] methane and the like. Examples of the organic sulfur-based antioxidant include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, disstearyl-3,3'-thiodipropionate, and pentaeryth. Examples thereof include lithyltetrakis (3-laurylthiopropionate). As these antioxidants, the above-exemplified antioxidants may be used alone or in combination of two or more.

Examples of the plasticizer include mineral oils, synthetic oils, and vegetable oils.

Specific examples of mineral oils include process oils (paraffin-based process oils, naphthen-based process oils, aroma-based process oils, etc.) and liquid paraffins. Specific examples of paraffin-based process oils include n-paraffin (butane, pentane, hexane, heptane, octane, nonan, decane, undecane, dodecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecan, eikosan, heneicosan, dokosan, etc. Tricosan, Tetracosan, Pentadecane, Hexacosan, Heptakosan, Octadecane, Nonakosan, Triacontan, Hentriacontan, Dotriacontan, Pentatriacontan, Hexacontane, Hemptacontane, etc.; Neohexane, 2,3-dimethylbutane, methylhexanes, 3-ethylpentane, dimethylpentane, 2,2,3-trimethylbutane, 3-methylheptane, dimethylhexanes, trimethylpentanes, isopentanes, 2-methylnonane , Isodecane, Isoundecan, Isododecane, Isotridecane, Isotetradecane, Isopentadecane, Isooctadecane, Isonanodecan, Isoeicosane, 4-Ethyl-5-methyloctane, etc.); Derivatives of these saturated hydrocarbons; etc. As a specific example of the naphthenic process oil, the naphthenic process oil refers to a process oil having a high naphthenic ring carbon number. Examples of the naphthenic ring compound contained in the naphthenic process oil include cyclic compounds having 3 or more carbon atoms. More specific examples of the naphthenic ring compound include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane.

Specific examples of synthetic oils include ether oil, ester oil, phosphoric acid ester, and chlorinated paraffin.

Specific examples of vegetable oils include olive oil, rice germ oil, corn oil, Southernca oil, camellia oil, castor oil, jojoba seed oil, and eucalyptus leaf oil.

As described above, the hot melt adhesive used in the package of the present embodiment comprises at least one of water and alcohol in a heat kneader during or after kneading the liquid hot melt adhesive material. The liquid is introduced in an amount of 0.03 part by mass or more with respect to 100 parts by mass of the hot melt adhesive material, and is removed while heating, stirring or dispersing so that the hot melt adhesive material and the liquid are in contact with each other. A hot melt adhesive obtained by a manufacturing method that involves taking care.

The present inventors have found that, surprisingly, the acetic acid odor of a package can be significantly reduced by using a hot melt adhesive obtained through the above process (manufacturing method). The manufacturing method will be described in more detail below.

The method for producing a hot melt adhesive used in the present embodiment includes a step of introducing a liquid into a heat kneader during or after kneading a liquid hot melt adhesive material, and heating, stirring or dispersing. , Including the step of degassing.

The step of introducing the liquid into the heat kneader may be performed during the kneading of the hot melt adhesive material after the hot melt adhesive material is put into the heat kneader, or the kneading is completed. You may go later. Preferably, it is done after the kneading of the materials is completed. In the present embodiment, "kneading is completed" means a state in which the material of the hot melt adhesive (for example, the base resin and the tackifier) shows uniform fluidity.

For the heat kneader, the general manufacturing equipment used for stirring and kneading the hot melt adhesive can be used. For example, in a general manufacturing method of a hot melt adhesive, there are a continuous processing method and a batch processing method. As a heat kneader used as a continuous processing method, a ruder, an extruder, a biaxial taper screw or the like can be used. Further, as the heat kneader used as the batch processing method, a stirring kneader, a Banbury mixer, a kneader or the like can be used.

The liquid to be introduced into the heat kneader is a liquid consisting of at least one of water and alcohol. That is, the liquid of the present embodiment may be water alone, alcohol alone, or an alcohol aqueous solution which is both water and alcohol.

When an alcohol aqueous solution is used as the liquid, the alcohol concentration is not particularly limited, but a dilute alcohol aqueous solution of 10% by mass or more is preferable from the viewpoint that a low odor effect can be obtained when the concentration is high. When an aqueous alcohol solution is used as the liquid, it is necessary to wash the material for EVA hot melt adhesive with water after introducing the liquid consisting of the aqueous alcohol solution. The washing method with water is not particularly limited, and the washing can be performed by introducing water into the heat kneader for a time equivalent to the time when the alcohol aqueous solution is brought into contact with the adhesive material.

The liquid is introduced into the heat kneader in an amount of 0.03 part by mass or more with respect to 100 parts by mass of the hot melt adhesive material. If the amount introduced is less than 0.03 parts by mass, the low odor effect cannot be obtained. The amount of the liquid introduced is more preferably 0.35 parts by mass or more.

In addition, there is no need to set the upper limit of the introduction amount because the lower odor effect will be higher if the introduction amount is large. However, in consideration of cost, process time, etc., it is preferably 50 parts by mass or less, more preferably 25 parts by mass or less, with respect to 100 parts by mass of the hot melt adhesive material.

The speed at which the liquid is introduced into the heat kneader is not particularly limited, but it is preferable to introduce the liquid at an introduction speed of about 50 ppm / min to 12500 ppm / min for the hot melt adhesive material.

The method for introducing the liquid in the present embodiment is not particularly limited, and the liquid may be introduced from above, on the side surface, or below the heat kneader. Specifically, for example, the liquid can be introduced in a state of being sufficiently diffused in the hot melt by introducing the liquid from below and / or from the side surface of the heat kneader.

After introducing the liquid into the heat kneader, degassing is performed while heating, stirring or dispersing the liquid so that the hot melt adhesive material and the liquid are in contact with each other. The heating temperature at this time is not particularly limited as long as it is equal to or higher than the melting temperature of the hot melt adhesive material, and can be appropriately set depending on the type of base resin used as the hot melt adhesive material and the like.

Heating, stirring and dispersion can be performed by means known in the art. For example, paddles, turbines, propellers, anchors, helical ribbons, max blends, full zones, screws, blades, MR-205, Hi-F mixers, sunmerers and the like can be used. These may be used individually by 1 type, or may be used in combination of 2 or more types.

It is preferable to perform degassing at a minute speed exhaust rate of 0.25 times the volume of the heat kneader or more until the gauge pressure becomes a vacuum degree higher than -60 kPa. By degassing under such conditions, the amount of residual acetic acid and residual vinyl acetate can be suppressed more sufficiently.

The degassing means of the present embodiment is not particularly limited, but specifically, for example, a vacuum pump adjusted to the minute speed exhaust speed is used, and degassing is performed by reducing the pressure until the vacuum degree is reached. can do.

The minute speed exhaust speed is more preferably equal to or larger than the volume of the heat kneader. Although it is not necessary to specify the upper limit of the minute speed exhaust speed, it is preferable that the volume is 17.5 times or less the volume of the heat kneader from the viewpoint of increasing the size of the equipment and controlling the cost.

It is more preferable that the degassing has a gauge pressure higher than −90 kPa. It is not necessary to set an upper limit, but it is desirable that the vacuum degree is lower than the gauge pressure -101 kPa from the viewpoint of equipment damage, equipment size increase, cost increase, and the like.

As described above, it is considered that by introducing a liquid into the hot melt adhesive material under specific conditions, the contact area can be increased by dispersing a normal gas, and the adsorption effect can be further improved. As a result, a low odor and odorless hot melt adhesive can be provided.

Further, the manufacturing method of the present embodiment may include a step of cooling and aggregating the exhaust gas exhausted from the heat kneader to recover the liquid containing the volatile organic compound.

This has the advantage that the life of the vacuum pump can be extended without impairing the lubricity and rust resistance of the vacuum pump.

Further, the recovery rate of the liquid in the recovery step is preferably 60% or more. As a result, it is considered that environmental air pollution can be further suppressed.

The hot melt adhesive obtained by the production method of this embodiment has a small amount of residual acetic acid and has a very low odor. Such a hot melt adhesive has a smaller residual odor component than a conventional hot melt adhesive commercially available, which is characterized by a low odor produced by selecting a polymer material containing a small amount of odor component in the material. Is a feature.

As the paper base material used for the package of the present embodiment, the paper base material conventionally used as the package of each product can be used without particular limitation. Specifically, as the paper base material, for example, paperboard, kraft paper, coated paper, carton paper, cardboard interleaving paper and the like can be used. Further, as the paperboard, for example, coated cardboard, white cardboard, Manila cardboard, chip cardboard, yellow paperboard, colored paperboard and the like can be used. As the paper substrate as described above, one type may be used alone, or two or more types may be used in combination.

Further, the paper base material may be provided with a pattern layer or a printing layer on at least one side. As a result, printing such as a product name and description and various designs can be applied to the surface of the package. Furthermore, in order to protect the surface of the package and impart designability, embossing, gloss, etc. to the surface of the paper base material with resistance such as stain resistance, cellophane tape peeling resistance, chemical resistance, etc., a resin film or the like is used. A protective layer may be further provided.

The shape of the package in the present embodiment is also not particularly limited, and can be appropriately selected depending on the product to be packaged, such as a box type, a tubular type, and a polyhedral type.

The package of the present embodiment is not particularly limited, but can be obtained by, for example, the following manufacturing method. First, a printing layer, a protective layer, or the like is provided on the paper base material as described above as needed, and the paper is cut according to a development drawing based on a desired shape of the package to obtain a paper pattern. The paper pattern is folded to form a package having a desired shape, and the above-mentioned hot melt adhesive that has been heated and melted is applied to a portion to be fixed. The coating method is not particularly limited, and a hot melt gun or various applicators can be used. After that, the paper pattern is bonded and cooled (cooled) to cure the hot melt adhesive, and the paper pattern is adhered and fixed to obtain a package.

The package of the present embodiment has a very low odor with a residual acetic acid amount of 17 ppb or less. Therefore, the package of the present embodiment can be used as a package of various products / products, but since the odor is greatly reduced, for example, for food, confectionery, toys, medical use, etc. It can be suitably used for various packages for pharmaceuticals and the like.

In the present embodiment, the residual acetic acid amount means a value measured by the method shown in Examples described later. Further, in the package of the present embodiment, a more preferable amount of residual acetic acid is 14 ppb or less.

As described above, this specification discloses various aspects of technology, of which the main technologies are summarized below.

According to the above configuration, it is possible to provide a package having a low odor even though a hot melt adhesive showing excellent adhesive performance is used.

Further, in the package, it is preferable that the paper base material is at least one selected from the group consisting of paperboard, kraft paper, coated paper, carton paper, and corrugated cardboard.

Further, the paper base material may be provided with a pattern layer or a printing layer on at least one side.

Further, in the package, it is preferable that the hot melt adhesive is an ethylene vinyl acetate hot melt adhesive. This has the advantage of being excellent in workability, adhesiveness, economy, and the like.

Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto.

First, the materials for hot melt adhesive used in this example are shown below.

-Hot melt adhesive 1 (EVA hot melt 1):
"Morescomelt (registered trademark) ME-125", viscosity at softening points 83 ° C and 160 ° C 2100 mPa · s
-Hot melt adhesive 2 (EVA hot melt 2):
"Morescomelt (registered trademark) K-1183", viscosity at softening point 100 ° C and 160 ° C, 3900 mPa · s
-Hot melt adhesive 3 (EVA hot melt 3):
"Morescomelt (registered trademark) PK-100S", viscosity 1500 mPa · s at softening point 112 ° C and 160 ° C
-Hot melt adhesive 4 (biomass hot melt 1):
"Morescomelt (registered trademark) PK-150Y", viscosity at softening points 103 ° C and 160 ° C 1850 mPa · s
-Hot melt adhesive 5 (biomass hot melt 2):
"Morescomelt (registered trademark) V-21", viscosity at softening points 90 ° C and 160 ° C 7000 mPa · s

(Manufacturing method A of hot melt adhesive)
2 kg of the hot melt adhesive material was put into a stirring kneader made of stainless steel (SUS) having a capacity of 4 L, and the hot melt adhesive was stirred and melted at a temperature equal to or higher than the melting point of each hot melt adhesive.

Then, 3.50 parts by mass or more of a dilute ethanol aqueous solution (10%) was introduced from the side surface or / or below of the kneader with respect to 100 parts by mass of the hot melt adhesive material. At a minute-speed exhaust rate (exhaust speed / tank volume) that is 0.45 times the volume of the kneader, degas until the gauge pressure of the kneader reaches a vacuum of -60 kPa, and apply the hot melt adhesive. Obtained.

(Manufacturing method B of hot melt adhesive)
2 kg of the hot melt adhesive material was put into a stirring kneader made of stainless steel (SUS) having a capacity of 4 L, and the hot melt adhesive was stirred and melted at a temperature equal to or higher than the melting point of each hot melt adhesive.

Then, 0.35 parts by mass or more of distilled water was introduced from the side surface and / or the lower side of the kneader with respect to 100 parts by mass of the hot melt adhesive material. At a minute-speed exhaust rate (exhaust speed / tank volume) that is 0.45 times the volume of the kneader, degas until the gauge pressure of the kneader reaches a vacuum of -90 kPa, and apply the hot melt adhesive. Obtained.

(Manufacturing method C of hot melt adhesive)
2 kg of the hot melt adhesive material was put into a stirring kneader made of stainless steel (SUS) having a capacity of 4 L, and the hot melt adhesive was stirred and melted at a temperature equal to or higher than the melting point of each hot melt adhesive.

Then, a dilute methanol aqueous solution (10%) of 21.00 parts by mass or more was introduced from the side surface or / or from below with respect to 100 parts by mass of the hot melt adhesive material. At a minute-speed exhaust rate (exhaust speed / tank volume) that is 2.25 times the volume of the kneader, degas until the gauge pressure of the kneader reaches a vacuum of -98 kPa, and apply the hot melt adhesive. Obtained.

(Preparation of samples for Examples 1 to 15)
First, the following paper materials were prepared as paper base materials:
・ Glico's "Visco" confectionery box paper (paperboard (coated cardboard))
・ Calbee's "Potato Chips Crisp" Confectionery Box Paper (Kraft Paper)
・ Morozoff's "PLAIN CHOCOLATE" confectionery box paper (paperboard (coated cardboard))
・ Epoch "Sylvanian Families" toy box paper (cardboard interleaving paper)
・ Paperboard cover (manufactured by KOKUYO, paperboard cover)
・ Coated paper (Oji Paper Co., Ltd., top coat)
・ Carton paper (white carton manufactured by Shimojima)
-Kraft paper (made by Rengo, kraft paper on the surface of K6 liner)

Then, two sheets of various paper substrates shown in Tables 1 to 3 are prepared as adherends, and a hot melt gun (Hakko Co., Ltd. No. 806-1) is used to apply a coating temperature of 180 ° C. and a coating amount of 3 g / m. A hot melt adhesive was applied to one side of one of the adherends. After 2 seconds had passed after the application, the other adherend was laminated, and the laminate obtained by pressing with a load of 7.8 kPa for 2 seconds was used as a test piece (packaging sample) for the following evaluation test.

(Sample of comparative example)
Comparative Example 1: The portion where two sheets of paper base material (paperboard (coated cardboard)) of Glico's "Visco" confectionery box was laminated (bonded) was used as a package sample of Comparative Example 1.

Comparative Example 2: The above sample was prepared by using the paper base material (kraft paper) of Calby's "Potato Chips Crisp" confectionery box as the paper base material and using the hot melt adhesive 1 as it is without any processing. A laminated body was prepared by the same method as the method, and used as a test piece (packaged sample).

Comparative Example 3: The above sample was prepared by using the paper base material (kraft paper) of Calby's "Potato Chips Crisp" confectionery box as the paper base material and using the hot melt adhesive 3 as it is without any processing. A laminated body was prepared by the same method as the method, and used as a test piece (packaged sample).

[Evaluation test 1: Measurement of residual acetic acid amount]
The amount of acetic acid in the test piece was measured by a gas chromatograph mass spectrometer (GC Agilent 7890B GC system, MS Agilent 5977B series GC / MSD system, DHS Gestel DHS system) and a dynamic headspace method. I went based on. As a pretreatment, each sample was heated at 160 ° C. for 60 minutes. The capillary column used had an inner diameter of 0.25 mm, a 5% phenyl / 95% dimethylpolysiloxane coating (coating thickness of 0.25 μm), and a length of 30 m. The column heating program was heated from 40 to 300 ° C. at 10 ° C./min and then held for 15 minutes. By this operation, the acetic acid detected by the mass spectrometer was quantified from the calibration curve.

[Evaluation test 2: Sensory evaluation of odor]
In a 140 mL glass bottle, four test pieces (packaged samples) bonded with a hot melt adhesive were placed in a size of 10 mm × 80 mm. The sample was heated in an atmosphere of 80 ° C. for 30 minutes, allowed to stand at room temperature for 10 minutes, and then smelled at a distance of 1 to 2 cm.

The evaluation criteria for the above sensory test are as follows.

⊚: Residual acetic acid amount 6 ppb or less No odor of acetic acid is felt ○: Residual acetic acid amount 7 to 17 ppb Low odor effect Δ: Residual acetic acid amount 18 to 24 ppb There is a slight low odor effect, but a clear odor remains. ×: Residual acetic acid amount 25 ppb or more Clearly odor is felt The grounds for ◎ above are based on the odor threshold published by the Nioi Kaori Environmental Association. Further, in the table, "<1" indicates that the remaining acetic acid amount was less than 1 ppb, and ">25" indicates that it exceeded 25 ppb (detection limit).

[Evaluation test 3: Peeling test]
After the test piece was left at 25 ° C. for 24 hours, one of the adherends in the test piece was peeled off by hand, and the material destruction rate (%) of the adherend was calculated. The material destruction rate of the adherend is the ratio (percentage) of the area of the portion where the adherend is broken to the area of the entire surface where the two adherends are adhered to each other. The evaluation criteria for this test were as follows.

⊚: Material fracture rate 80% or more ◯: Material fracture rate 60% or more and less than 80% Δ: Material fracture rate 40% or more and less than 60% ×: Material fracture rate less than 40% The respective results are shown in Tables 1 to 3.

(Discussion)
As is clear from the results in Tables 1 to 3, in the packages (Examples 1 to 15) according to the present invention, the amount of acetic acid is 17 ppb or less and the odor is also odor regardless of the type of the paper base material. It was reduced. In addition, as can be seen from the results of the peeling test, it was confirmed that the paper substrate was firmly fixed and the material was destroyed.

On the other hand, in Comparative Example 1 in which a commercially available general paper-based confectionery box was used as it was, the amount of residual acetic acid in the package was large and an odor was felt. Further, in Comparative Example 2 in which the hot melt adhesive 1 was used as it was without processing, and in Comparative Example 3 in which the hot melt adhesive 3 was used as it was without processing for adhering a general paper-based confectionery box. , The amount of residual acetic acid in the package was large, and an odor was felt.

This application is based on Japanese Patent Application No. 2020-101366 filed on June 11, 2020, the contents of which are included in the present application.

In order to express the present invention, the present invention has been appropriately and sufficiently described through the embodiments with reference to the specific examples described above, but it is easy for a person skilled in the art to change and / or improve the above-described embodiments. It should be recognized that it can be done. Therefore, unless the modified or improved form implemented by a person skilled in the art is at a level that deviates from the scope of rights of the claims stated in the claims, the modified form or the improved form is the scope of rights of the claims. It is interpreted to be included in.

The present invention has a wide range of industrial applicability in the technical field of a package made of a paper medium using a hot melt adhesive.

Claims

A package in which the paper substrate is fixed with a hot melt adhesive.
While the hot melt adhesive kneads the liquid hot melt adhesive material or after kneading, 100 parts by mass of the hot melt adhesive material is charged with a liquid consisting of at least one of water and alcohol in a heat kneader. Hot obtained by a production method including degassing while heating, stirring or dispersing the liquid so that the hot melt adhesive material and the liquid are in contact with each other by introducing the hot melt adhesive in an amount of 0.03 part by mass or more. Being a melt adhesive, as well as
A package having a residual acetic acid amount of 17 ppb or less.
The package according to claim 1, wherein the paper base material is at least one selected from the group consisting of paperboard, kraft paper, coated paper, carton paper, and corrugated cardboard.
The package according to claim 1 or 2, wherein the paper base material has a pattern layer or a print layer on at least one side.
The package according to any one of claims 1 to 3, wherein the hot melt adhesive is an ethylene vinyl acetate hot melt adhesive.