JP2018079988A - Packaging material and packaging container using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material for preventing delamination between a barrier layer and a heat seal layer.SOLUTION: In a packaging material 110 including at least a base material layer 112, a barrier layer 114 having gas barrier property and a heat seal layer 116 disposed as the innermost layer and made of a heat adhesive resin, which are laminated in order, the heat seal layer 116 includes a layer composed of cyclic olefin copolymer, and an adhesive layer 115 for bonding the barrier layer 114 and the heat seal layer 116 is composed of an ethylene methacrylic acid copolymer disposed on the barrier layer 114 side and a linear low density polyethylene disposed on the heat seal layer side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a packaging material used for a container for storing food, medicine, and the like, and a packaging container using the same.

  Conventionally, as packaging materials used for packaging containers, a base material layer made of a paper base material, a barrier layer for preventing gas permeation, a heat seal layer made of a heat-adhesive resin, and a barrier layer and a heat seal layer are bonded. A laminate having an adhesive layer to be used has been used. Here, a low-density polyethylene resin was used for the heat seal layer, and a polyurethane-based adhesive, which is an adhesive for dry lamination, was used for the adhesive layer. In a packaging container formed using this packaging material, alcoholic beverages such as sake and shochu and non-alcoholic beverages such as coffee and fruit beverages are packaged. However, there is a problem that the odor component caused by the solvent of the polyurethane adhesive used for the adhesive layer passes through the heat seal layer and moves into the content, thereby impairing the quality of the content, particularly the taste.

  In order to solve this problem, Patent Document 1 includes a layer made of a cyclic olefin copolymer in the heat seal layer. The cyclic olefin copolymer has a property that it is difficult to transmit odor caused by the solvent of the polyurethane adhesive. For this reason, the permeation | transmission of the odor resulting from the solvent of a polyurethane-type adhesive agent can be interrupted | blocked by a heat seal layer, and the quality fall of the packaged content can be prevented.

JP 2008-221606 A

  However, according to the packaging material, components such as alcohol contained in the contents in the packaging container pass through the heat seal layer and reach the barrier layer, and are accumulated between the barrier layer and the heat seal layer. For this reason, there has been a problem in that delamination occurs between the barrier layer and the heat seal layer due to deterioration of the adhesive layer made of the polyurethane-based adhesive due to long-term use.

  An object of this invention is to provide the packaging material which prevents the delamination of a barrier layer and a heat seal layer in view of the said problem.

  In order to achieve the above object, the present invention provides a packaging material in which at least a base material layer, a barrier layer having a gas barrier property, and a heat seal layer made of a heat-adhesive resin are sequentially laminated, An ethylene methacrylic acid copolymer disposed on the barrier layer side and an adhesive layer for adhering the barrier layer and the heat seal layer, including a layer made of a cyclic olefin copolymer; It is characterized by being made of chain low density polyethylene.

In the packaging material having the above-described configuration, the melting point of the linear low density polyethylene and the ethylene methacrylic acid copolymer constituting the adhesive layer is 100 ° C. or less, and the linear low density polyethylene has a density of 0. .92 g / cm ³ and the acid content of the ethylene methacrylic acid copolymer is less than 10% by mass percentage.

  The present invention also provides a packaging material in which at least a base material layer, a barrier layer having a gas barrier property, and a heat seal layer made of a heat-adhesive resin are sequentially laminated in the packaging material having the above-described configuration, Includes a layer made of a cyclic olefin copolymer, and the adhesive layer for bonding the barrier layer and the heat seal layer is made of an ethylene methacrylic acid copolymer having a thickness of 25 μm or more.

  In the packaging material having the above-described configuration, the ethylene methacrylic acid copolymer constituting the adhesive layer has a melting point of 100 ° C. or less and the ethylene methacrylic acid copolymer has an acid content of less than 10% by mass. It is characterized by being.

  According to the present invention, in the packaging material having the above-described configuration, the adhesive layer is formed by melt extrusion.

  According to the present invention, in the packaging material configured as described above, the heat seal layer has a layer made of linear low density polyethylene having a thickness of 5 μm or less on a surface opposite to the adhesive layer.

  According to the present invention, in the packaging material configured as described above, the heat seal layer is formed of a blend resin of linear low density polyethylene and a cyclic olefin copolymer having a thickness of 10 μm or less on the surface opposite to the adhesive layer. It is characterized by having a layer.

  According to the present invention, in the packaging material configured as described above, the heat seal layer has a layer made of a cyclic olefin copolymer on a surface in contact with the adhesive layer.

  According to the present invention, in the packaging material having the above-described configuration, the heat seal layer has a layer made of linear low density polyethylene on a surface in contact with the adhesive layer.

  Moreover, the present invention is characterized in that, in the packaging material configured as described above, the base material layer includes a paper base material.

  In addition, the present invention is a packaging container made of the packaging material having the above-described configuration, and is characterized by being formed by heat-sealing an end portion of the packaging material.

  Further, the present invention is a packaging container comprising the packaging material having the above-described configuration, wherein the packaging material is formed by heat-sealing an end portion, and the heat-sealing strength of the heat-sealing portion is 25 N / 15 mm or more. Yes.

  According to the present invention, the barrier layer and the heat seal layer are bonded by the adhesive layer made of the ethylene methacrylic acid copolymer disposed on the barrier layer side and the linear low density polyethylene disposed on the heat seal layer side. Thereby, a barrier layer and an ethylene methacrylic acid copolymer are adhere | attached firmly, and a heat seal layer and a linear low density polyethylene are adhere | attached firmly. Moreover, the interlayer adhesive strength of a linear low density polyethylene and an ethylene methacrylic acid copolymer is also high. For this reason, the barrier layer and the heat seal layer can be bonded with high laminate strength. In addition, the ethylene methacrylic acid copolymer and the linear low-density polyethylene are less likely to be deteriorated even after many years of use as compared with the adhesive for dry lamination, and the odor caused by the solvent is small. Therefore, delamination between the barrier layer and the heat seal layer can be prevented, and the odor component that permeates through the heat seal layer can be reduced and the initial quality of the contents can be maintained well.

  According to the present invention, the barrier layer and the heat seal layer are bonded by the adhesive layer made of an ethylene methacrylic acid copolymer having a thickness of 25 μm or more. As a result, the barrier layer and the heat seal layer can be bonded with high laminate strength. The ethylene methacrylic acid copolymer is less likely to be deteriorated by long-term use than the adhesive for dry lamination, and has less odor due to the solvent. Therefore, delamination between the barrier layer and the heat seal layer can be prevented, and the odor component that permeates through the heat seal layer can be reduced and the initial quality of the contents can be maintained well.

The perspective view of the packaging container which concerns on 1st Embodiment of this invention. Schematic sectional view showing the layer structure of the packaging material according to the first embodiment of the present invention Schematic sectional drawing which shows the layer structure of the heat seal layer of the packaging material which concerns on 1st Embodiment of this invention. Schematic sectional view showing the layer structure of the packaging material according to the second embodiment of the present invention

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a packaging container 10 according to the first embodiment.

  The packaging container 10 is formed in a box shape by overlapping the end portions of the packaging material 110 (see FIG. 2) cut into a predetermined shape and heat-sealing the heat seal portions 11a and 11b with a predetermined width. In the heat seal part 11a, the innermost heat seal layer 116 (see FIG. 2) of the packaging material 110 is opposed and heat sealed. The heat seal portion 11b is heat sealed by a skive hemming method. Specifically, the outermost layer side of the edge of the packaging material 110 is cut (skived) to a predetermined thickness, the heat seal layer 116 disposed on the innermost layer is folded back to the outermost layer side, folded (hemmed), The heat seal layer 116 that overlaps with the heat seal layer 116 folded back to the outer layer side is opposed to the heat seal layer. This prevents the cross section from coming into contact with the contents at the edge of the packaging material 110, contaminates the contents, penetrates through the paper layer of the packaging material 110, and the strength of the laminate decreases. Problems such as delamination and poor sealing performance can be prevented. Non-alcoholic beverages such as fruit juice beverages, juices, teas, coffee, milk beverages, soups, alcoholic beverages such as sake and shochu, and chemicals containing menthol components are enclosed in the packaging container 10 as contents (not shown). ing.

  FIG. 2 is a schematic cross-sectional view showing the layer structure of the packaging material 110. The packaging material 110 is composed of a laminate in which a base material layer 112, a barrier layer 114, and a heat seal layer 116 are sequentially laminated. The base material layer 112 and the barrier layer 114 are bonded via an adhesive layer 113. Further, the barrier layer 114 and the heat seal layer 116 are bonded via an adhesive layer 115.

  The base material layer 112 is disposed on the outer surface side of the packaging container 10 (see FIG. 1) and is made of paper. In addition, a thermal adhesive resin layer 117 made of polyethylene is formed on the upper surface of the base material layer 112. The thermal adhesive resin layer 117 is formed by melting and extruding polyethylene on the upper surface of the base material layer 112. The thermal adhesive resin layer 117 imparts water resistance to the packaging container 10 formed of the packaging material 110. Further, printing is performed on the upper surface of the heat-adhesive resin layer 117.

  The base material layer 112 imparts rigidity, waist, strength and the like to the packaging container 10. Specifically, various types of paper such as pure white roll paper, kraft paper, paperboard, and processed paper can be used.

  The adhesive layer 113 is composed of a resin layer that adheres the base material layer 112 and the barrier layer 114 by a dry lamination method, an extrusion lamination method, a coextrusion lamination method, a thermal lamination method, or the like. In the dry laminating method, for example, a polyurethane adhesive or the like is used. Extrusion resins used in the extrusion laminating method and coextrusion laminating method are less susceptible to deterioration of the adhesive layer even when used for many years compared to the adhesive used in the dry laminating method, and between the base material layer 112 and the barrier layer 114. Delamination is unlikely to occur. For this reason, it is preferable to use an extrusion lamination method or a coextrusion lamination method.

  The barrier layer 114 has a gas barrier property, prevents water vapor and oxygen from entering the inside of the packaging container 10 from the outside, and the contents components (for example, odor component, alcohol component, menthol component) outside the packaging container 10. Etc.) is prevented from leaking. The barrier layer 114 is made of a heat-resistant resin film (eg, polyethylene terephthalate or polyethylene naphthalate), a heat-resistant resin film on which an inorganic compound (silicon oxide, alumina, silica, etc.) is deposited, a metal foil (aluminum, nickel, etc.), etc. Can be used. In the heat resistant resin film on which the inorganic compound is deposited, the deposited surface of the deposited inorganic compound is disposed on the adhesive layer 113 side.

  The adhesive layer 115 bonds the barrier layer 114 and the heat seal layer 116, and has an upper layer portion 115a disposed on the barrier layer 114 side and a lower layer portion 115b disposed on the heat seal layer 116 side. The upper layer portion 115a is made of ethylene methacrylic acid copolymer (EMMA), and the lower layer portion 115b is made of linear low density polyethylene (LLDPE).

  The barrier layer 114 (heat-resistant resin film or metal foil) and the upper layer 115a made of an ethylene methacrylic acid copolymer are firmly bonded, and the heat seal layer 116 and the lower layer 115b are firmly bonded. Moreover, the interlayer adhesive strength of a linear low density polyethylene and an ethylene methacrylic acid copolymer is also high. Therefore, the barrier layer 114 and the heat seal layer 116 are bonded with high laminate strength through the ethylene methacrylic acid copolymer and the linear low density polyethylene without using an adhesive such as an anchor coat agent. In addition, the ethylene methacrylic acid copolymer and the linear low-density polyethylene are less likely to be deteriorated even after many years of use as compared with the adhesive for dry lamination, and the odor caused by the solvent is small. Therefore, delamination between the barrier layer 114 and the heat seal layer 116 can be prevented, and the odor component that permeates the heat seal layer 116 can be reduced, and the initial quality of the contents can be maintained well.

  The adhesive layer 115 is preferably composed of a co-extruded resin of an ethylene methacrylic acid copolymer and a linear low density polyethylene. In this case, the melted ethylene methacrylic acid copolymer and linear low-density polyethylene are coextruded on the surface of the barrier layer 114, and a resin film constituting the heat seal layer 116 is bonded. Thereby, the barrier layer 114 and the heat seal layer 116 can be easily bonded.

Further, the melting point of the ethylene methacrylic acid copolymer and the linear low density polyethylene constituting the adhesive layer 115 is preferably 100 ° C. or less. Thereby, even if these resins are melt-extruded at a low temperature, a high laminate strength can be obtained. Further, by melt extrusion at a low temperature, it is possible to reduce the generation of odor of the ethylene methacrylic acid copolymer and the linear low density polyethylene. At this time, by setting the density of the linear low density polyethylene to less than 0.92 g / cm ³ and the acid content of the ethylene methacrylic acid copolymer to be less than 10% by mass percentage, the ethylene methacrylic acid copolymer and Odor generation of linear low density polyethylene can be further reduced.

  FIG. 3 is a schematic cross-sectional view showing an example of the layer configuration of the heat seal layer 116. The heat seal layer 116 is melted by heat and heat-sealed with the opposing heat seal layers 116. Specifically, layers made of linear low density polyethylene (hereinafter referred to as LLDPE layers 116a and 116c) are arranged on both sides of a layer made of cyclic olefin copolymer (COC) (hereinafter referred to as COC layer 116b). Has been.

  The COC layer 116 b prevents components of the adhesive layer 115 from penetrating into the packaging container 10. Thereby, the component of the adhesive layer 115 does not migrate into the contents, and the initial quality of the contents can be maintained well.

  Further, the COC layer 116b prevents components of the contents from being transmitted from the inside of the packaging container 10 to the adhesive layer 115 side. For example, when the content contains an alcohol component, the alcohol component can be prevented from transmitting to the adhesive layer 115 side. Thereby, the deterioration of the adhesive layer 115 can be prevented, and the delamination between the barrier layer 114 and the upper layer portion 115a or the delamination between the upper layer portion 115a and the lower layer portion 115b can be prevented. Moreover, when the content contains a menthol component, it is possible to suppress the menthol component from being transmitted to the adhesive layer 115 side. Thereby, the quality fall by the menthol component reduction | decrease of the content can be prevented.

  Examples of the cyclic olefin copolymer constituting the COC layer 116b include ethylene / cyclic olefin copolymer random copolymer, hydrogenated product of ring-opening copolymer of cyclic olefin copolymer, and graft-modified ethylene / cyclic olefin. Examples thereof include a random copolymer, a ring-opening copolymer of a graft-modified cyclic olefin copolymer, and the like.

  Further, the LLDPE layer 116c disposed in the innermost layer of the heat seal layer 116 has excellent sealing properties, and the heat seal layers 116 are firmly heat-bonded to each other by heat sealing. In addition, the heat seal layer 116 is thermally bonded to the heat adhesive resin layer 117 provided outside the base material layer 112 with high heat seal strength. Note that the LLDPE layer 116c preferably has a thickness of 5 μm or less. By setting the thickness of the LLDPE layer 116c to 5 μm or less, it is possible to prevent the components of the contents from being adsorbed and to prevent deterioration of the contents. At this time, the heat seal strength between the LLDPE layers 116c (each LLDPE layer 116c after heat sealing cut to a width of 15 mm is grasped, and the gripping direction is 180 degrees in the opposite direction along the resin flow direction at a relative speed of 300 mm / min. By setting the heat seal strength (measured while peeling using a tensile tester) to 25 N / 15 mm or more, high sealability can be obtained in the heat seal portions 11 a and 11 b of the packaging container 10.

  Instead of the LLDPE layer 116c, a layer made of a blend resin of linear low density polyethylene and a cyclic olefin copolymer (hereinafter referred to as a blend resin layer) may be disposed in the innermost layer of the heat seal layer 116. . The blend resin layer is preferably 10 μm or less in thickness. By setting the thickness of the blend resin layer to 10 μm or less, it is possible to prevent the components of the contents from being adsorbed and prevent the quality of the contents from deteriorating. At this time, the heat sealing strength between the blend resin layers (each blend resin layer after heat sealing cut to a width of 15 mm is grasped, and the gripping direction is 180 degrees in the opposite direction along the resin flow direction at a relative speed of 300 mm / min. By setting the heat seal strength (measured while peeling using a tensile tester) to 25 N / 15 mm or more, high sealability can be obtained in the heat seal portions 11 a and 11 b of the packaging container 10.

  In addition, since the LLDPE layer 116a disposed on the surface of the heat seal layer 116 that is in contact with the adhesive layer 115 is made of the same resin as the lower layer portion 115b, the LLDPE layer 116a is bonded with high laminate strength. Even if a layer made of a cyclic olefin copolymer is disposed on the surface of the heat seal layer 116 that contacts the adhesive layer 115, a high laminate strength can be obtained with the lower layer portion 115 b.

  Other laminated structures of the heat seal layer 116 include, for example, a four-layer structure of cyclic olefin copolymer / linear low density polyethylene / cyclic olefin copolymer / linear low density polyethylene, linear low density polyethylene / Examples thereof include a three-layer structure of a blend resin of a cyclic olefin copolymer / linear low density polyethylene and a cyclic olefin copolymer. In addition, the component of the adhesive layer 115 which permeate | transmits the heat seal layer 116, and the component of the content can be reduced more by making the layer which consists of a cyclic olefin copolymer into a multilayer structure.

  According to the present embodiment, the barrier layer 114 and the heat seal layer 116 are formed by the adhesive layer 115 made of an ethylene methacrylic acid copolymer disposed on the barrier layer 114 side and a linear low density polyethylene disposed on the heat seal layer 116 side. Are glued together. Thereby, the barrier layer 114 and the ethylene methacrylic acid copolymer are firmly bonded, and the heat seal layer 116 and the linear low density polyethylene are firmly bonded. Moreover, the interlayer adhesive strength of a linear low density polyethylene and an ethylene methacrylic acid copolymer is also high. For this reason, the barrier layer 114 and the heat seal layer 116 can be bonded with high laminate strength. In addition, the ethylene methacrylic acid copolymer and the linear low-density polyethylene are less likely to be deteriorated even after many years of use as compared with the adhesive for dry lamination, and the odor caused by the solvent is small. Therefore, delamination between the barrier layer 114 and the heat seal layer 116 can be prevented, and the odor component that permeates the heat seal layer 116 can be reduced, and the initial quality of the contents can be maintained well.

Further, when the melting point of the linear low density polyethylene and the ethylene methacrylic acid copolymer constituting the adhesive layer 115 is 100 ° C. or less, the barrier layer 114 and the heat seal layer 116 are not melted and extruded at a low temperature. A high laminate strength can be obtained. Moreover, generation | occurrence | production of the resin odor of a linear low density polyethylene and an ethylene methacrylic acid copolymer can be suppressed by melt-extruding at low temperature. Further, by setting the density of the linear low density polyethylene to less than 0.92 g / cm ³ and the acid content of the ethylene methacrylic acid copolymer to be less than 10% by mass percentage, linear low density polyethylene and ethylene Odor generation of the methacrylic acid copolymer can be further reduced.

  When the heat seal layer 116 has a linear low density polyethylene having a thickness of 5 μm or less on the innermost layer side surface, or a linear low density polyethylene and a cyclic olefin having a thickness of 10 μm or less on the innermost layer side surface. In the case of having a layer made of a blend resin with a copolymer, it is possible to prevent the components of the contents from being adsorbed in the heat seal layer 116 and to prevent the quality of the contents from deteriorating.

  In addition, the heat seal layer 116 is provided with a layer made of a cyclic olefin copolymer or a layer made of linear low-density polyethylene on the surface in contact with the adhesive layer 115, so that the layer made of the cyclic olefin copolymer and the adhesive layer 115. The linear low-density polyethylene can be firmly bonded, and delamination between the barrier layer 114 and the heat seal layer 116 can be further prevented.

  Further, by setting the heat seal strength of the heat seal layer 116 to 25 N / 15 mm in the heat seal portion 11 b after forming the packaging container 10, high sealing performance can be obtained in the heat seal portion 11 b of the packaging container 10.

Second Embodiment
FIG. 4 is a schematic cross-sectional view showing the layer structure of the packaging material 110 according to the second embodiment. For convenience of explanation, the same reference numerals are given to the same descriptions as those in the first embodiment shown in FIGS. In the packaging material 110 of this embodiment, the adhesive layer 115 is formed only of an ethylene methacrylic acid copolymer having a thickness of 25 μm or more. If the ethylene methacrylic acid copolymer has a thickness of 25 μm or more, the barrier layer 114 and the heat seal layer 116 can be bonded with high laminate strength without using an adhesive such as an anchor coat agent. In addition, the ethylene methacrylic acid copolymer is less likely to deteriorate even after many years of use and has less odor due to the solvent as compared with the adhesive for dry lamination. Therefore, delamination between the barrier layer 114 and the heat seal layer 116 can be prevented, and the odor component that permeates the heat seal layer 116 can be reduced, and the initial quality of the contents can be maintained well.

  At this time, the melting point of the ethylene methacrylic acid copolymer is preferably 100 ° C. or less. Thereby, even if the ethylene methacrylic acid copolymer is melt-extruded at a low temperature, a high laminate strength can be obtained. Moreover, generation | occurrence | production of the odor of an ethylene methacrylic acid copolymer can be reduced by melt-extruding at low temperature. The acid content of the ethylene methacrylic acid copolymer is preferably less than 10% by mass percentage. Thereby, when the barrier layer 114 has polyethylene terephthalate, a high laminate strength can be obtained between the adhesive layer 115 and the polyethylene terephthalate even if melt extrusion is performed at a low temperature.

  In addition, this invention is not limited to embodiment mentioned above, The case where it is set as the structure which does not contain a paper base material when the base material layer 112 is comprised in multiple layers is also contained in this invention. For example, a pouch-shaped packaging container 10 formed of the packaging material 110 having the base material layer 112 as the outermost layer is also included in the present invention. In this case, various films such as a polyethylene terephthalate film, a biaxially stretched nylon film, and a biaxially stretched polypropylene film can be used for the base material layer 112. When the pouch-shaped packaging container 10 is formed or when the skive hemming method is not used, the heat seal strength between the heat seal layer 116 and the base material layer 112 and the heat between the heat seal layer 116 and the heat adhesive resin layer 117 are obtained. Seal strength (Heat seal layer 116 and heat-adhesive resin layer 117 after heat sealing cut to a width of 15 mm are gripped and pulled 180 ° apart in the opposite direction along the resin flow direction at a relative speed of 300 mm / min. The heat seal strength measured while peeling using a tester is preferably 25 N / 15 mm or more. Thereby, the packaging container 10 formed by heat-sealing the innermost layer and the outermost layer at the edge of the packaging material 110 has high sealing performance.

  Next, the effects of the present invention will be specifically described using examples and comparative examples. In the following experiments, the laminate strength of the packaging material 110 and the quality retention performance and non-adsorption property with respect to the contents were evaluated.

  Table 1 shows the layer configuration of the adhesive layer 115 and the layer configuration of the heat seal layer 116 of the packaging materials according to Examples 1 to 6 and Comparative Examples 1 to 8 shown below.

The barrier layer 114 of the packaging material 110 according to Example 1 is formed of a polyethylene terephthalate film having a thickness of 12 μm. The upper layer portion 115a of the adhesive layer 115 is formed of an ethylene methacrylic acid copolymer (AN4228C manufactured by Mitsui DuPont Chemical Co., Ltd.) having a thickness of 10 μm and an acid content of 4%. The lower layer 115b of the adhesive layer 115 is formed of linear low density polyethylene (SP1071C, manufactured by Prime Polymer Co., Ltd.) having a thickness of 20 μm, a density of 0.91 g / cm ^{3, and a} melting point of 100 ° C.

  The heat seal layer 116 has a cyclic olefin copolymer (thickness 5 μm), a linear low density polyethylene (thickness 15 μm), a cyclic olefin copolymer (thickness 5 μm), a linear low density polyethylene (thickness 5 μm). The sealant film laminated in the order of) was used. Then, the packaging material 110 was formed by the melt coextrusion method in which the ethylene methacrylic acid copolymer of the adhesive layer 115 and the linear low density polyethylene were coextruded on the barrier layer 114 and the sealant film of the heat seal layer 116 was laminated. . At this time, the cyclic olefin copolymer of the heat seal layer 116 was disposed on the adhesive layer 115 side, and the linear low density polyethylene was disposed on the opposite side of the adhesive layer 115.

The adhesive layer 113 is formed of an ethylene methacrylic acid copolymer having a thickness of 20 μm (AN4228C manufactured by Mitsui DuPont Chemical Co., Ltd.), and the barrier layer 114 and the base material layer 112 (basis weight 360 g / m ² ) are adhered. . The thermoadhesive resin layer 117 is formed to a thickness of 25 μm by an extruded resin, and a printing layer is formed on the upper surface of the thermoadhesive resin layer 117.

  The packaging material 110 according to the second embodiment has the same layer configuration except for the packaging material 110 according to the first embodiment and the heat seal layer 116. The heat seal layer 116 of the packaging material 110 according to Example 2 is a laminate of linear low density polyethylene (thickness 20 μm), cyclic olefin copolymer (thickness 5 μm), and linear low density polyethylene (thickness 5 μm). A sealed film was used. At this time, linear low-density polyethylene having a thickness of 20 μm is disposed on the adhesive layer 115 side.

  The packaging material 110 according to the third embodiment has the same layer configuration except for the packaging material 110 according to the first embodiment and the heat seal layer 116. The heat seal layer 116 of the packaging material 110 according to Example 3 is composed of a linear low density polyethylene (thickness 15 μm), a cyclic olefin copolymer (thickness 5 μm), a linear low density polyethylene and a cyclic olefin copolymer. A sealant film in which blend resin (thickness: 10 μm) was laminated in order was used. At this time, a linear low-density polyethylene having a thickness of 15 μm is disposed on the adhesive layer 115 side.

The packaging material 110 according to the fourth embodiment is formed in the same layer configuration as the packaging material 110 according to the first embodiment, and the characteristics of the adhesive layer 115 are different. The adhesive layer 115 is formed by co-extrusion, and the upper layer portion 115a is formed of an ethylene methacrylic acid copolymer (AN42012C manufactured by Mitsui DuPont Chemical Co., Ltd.) having a thickness of 15 μm, an acid content of 9%, and a melting point of 100 ° C. The lower layer 115b of the adhesive layer 115 is formed of linear low density polyethylene (UJ370 manufactured by Prime Polymer Co., Ltd.) having a thickness of 15 μm, a density of 0.921 g / cm ^{3, and a} melting point of 121 ° C.

  The packaging material according to Example 5 is formed in the same layer configuration as the packaging material 110 according to Example 2, and the characteristics of the heat seal layer 116 are different. The packaging material according to Example 5 is a linear low density polyethylene (thickness 15 μm), a cyclic olefin copolymer (thickness 5 μm), a linear low density polyethylene (thickness 10 μm) on the sealant film of the heat seal layer 116. The sealant films laminated in the order of were used. At this time, a linear low-density polyethylene having a thickness of 15 μm is disposed on the adhesive layer 115 side.

  The packaging material according to Example 6 has the same layer configuration except for the packaging material 110 according to Example 1 and the adhesive layer 115. The packaging material according to Example 6 was an ethylene methacrylic acid copolymer (AN42012C manufactured by Mitsui DuPont Chemical Co., Ltd.) melted on one surface of a polyethylene terephthalate film (thickness 12 μm), a thickness 25 μm, an acid content 9%, a melting point 100 ° C.) was extruded to adhere the sealant film as the heat seal layer 116.

[Comparative Example 1]
The packaging material according to Comparative Example 1 has the same layer configuration except for the packaging material 110 according to Example 1, the adhesive layer 115 and the heat seal layer 116. In the packaging material according to Comparative Example 1, a sealant film as a heat seal layer 116 was bonded to one surface of a barrier layer 114 made of a polyethylene terephthalate film (thickness: 12 μm) through a dry laminating adhesive. Here, the sealant film includes a cyclic olefin copolymer (thickness 15 μm), a linear low density polyethylene (thickness 25 μm), a cyclic olefin copolymer (thickness 15 μm), and a linear low density polyethylene (thickness). Films laminated in the order of 5 μm) were used. At this time, a cyclic olefin copolymer having a thickness of 15 μm is disposed on the adhesive layer 115 side.

[Comparative Example 2]
The packaging material according to Comparative Example 2 has the same layer configuration except for the packaging material 110 according to Example 1, the adhesive layer 115, and the heat seal layer 116. The packaging material according to Comparative Example 2 is bonded to the sealant film, which is the heat seal layer 116, via an adhesive for dry lamination that forms the adhesive layer 115 on one surface of the barrier layer 114 made of a polyethylene terephthalate film (thickness 12 μm). did. Here, a linear low density polyethylene film having a thickness of 60 μm was used as the sealant film.

[Comparative Example 3]
The packaging material according to Comparative Example 3 has the same layer configuration except for the packaging material 110 according to Example 1, the adhesive layer 115, and the heat seal layer 116. The packaging material according to Comparative Example 3 was formed by extruding molten polyethylene (thickness 30 μm) forming an adhesive layer 115 on one surface of a barrier layer 114 made of a polyethylene terephthalate film (thickness 12 μm) to adhere a sealant film. Here, a film made of linear low density polyethylene (thickness 30 μm) was used as the sealant film as the heat seal layer 116. An anchor coating agent was applied to the surface of the polyethylene terephthalate film on the adhesive layer 115 side.

[Comparative Example 4]
The packaging material according to Comparative Example 4 has the same layer configuration except for the packaging material 110 according to Example 1 and the adhesive layer 115. The packaging material according to Comparative Example 4 is a sealant that is a heat seal layer 116 by extruding molten polyethylene (thickness 30 μm) forming an adhesive layer 115 on one surface of a barrier layer 114 made of a polyethylene terephthalate film (thickness 12 μm). The film was glued. An anchor coating agent was applied to the surface of the polyethylene terephthalate film on the adhesive layer 115 side.

[Comparative Example 5]
The packaging material according to Comparative Example 5 has the same layer configuration except for the packaging material 110 according to Example 1 and the adhesive layer 115. The packaging material according to Comparative Example 5 is a molten ethylene methacrylic acid copolymer (AN42012C manufactured by Mitsui DuPont Chemical Co., Ltd.) that forms an adhesive layer 115 on one surface of a barrier layer 114 made of a polyethylene terephthalate film (thickness 12 μm). The sealant film as the heat seal layer 116 was adhered by extruding 20 μm thickness, acid content 9%, melting point 100 ° C.).

[Comparative Example 6]
The packaging material according to Comparative Example 6 has the same layer configuration except for the packaging material 110 according to Example 1 and the adhesive layer 115. A packaging material according to Comparative Example 6 is a molten ethylene methacrylic acid copolymer (AN4228C manufactured by Mitsui DuPont Chemical Co., Ltd.) that forms an adhesive layer 115 on one surface of a barrier layer 114 made of a polyethylene terephthalate film (thickness: 12 μm). A sealant film as a heat seal layer 116 was adhered by extruding a material having a thickness of 20 μm and an acid content of 4%.

[Comparative Example 7]
The packaging material according to Comparative Example 7 has the same layer configuration except for the packaging material 110 according to Example 1 and the adhesive layer 115. The packaging material according to Comparative Example 7 is a melted linear low-density polyethylene (manufactured by Prime Polymer Co., Ltd., SP1071C thickness) that forms an adhesive layer 115 on one surface of a barrier layer 114 made of a polyethylene terephthalate film (thickness 12 μm). 30 μm, density 0.91 g / cm ^3, melting point 100 ° C.) was extruded to adhere the sealant film as the heat seal layer 116.

[Comparative Example 8]
The packaging material according to Comparative Example 8 has the same layer configuration except for the packaging material 110 according to Example 1 and the adhesive layer 115. In the packaging material according to Example 8, the adhesive layer 115 is made of an ethylene methacrylic acid copolymer (manufactured by Mitsui DuPont Chemical Co., Ltd., AN42012C thickness 15 μm, acid content 9%, melting point 100 ° C.) and low density polyethylene (LDPE) ( (Manufactured by Prime Polymer Co., Ltd., LC602A, thickness 15 μm, density 0.919 g / cm ^3, melting point 107 ° C.).

[Evaluation of laminate strength]
Evaluation of the laminate strength was performed by measuring changes in the laminate strength between the barrier layer 114 and the adhesive layer 115 and between the adhesive layer 115 and the heat seal layer 116 of the packaging materials according to Examples 1 to 6 and Comparative Examples 1 to 8. I went there. Further, the change in the laminate strength between the adhesive layer 115 and the heat seal layer 116 after being immersed in the contents was also measured.

  The specific method is to create a plurality of 15 cm × 25 cm packaging bags (heat seal width 10 mm) by heat-sealing the ends using the packaging materials according to Examples 1 to 6 and Comparative Examples 1 to 8, and the inside Hypochlorous acid was added and sealed. This packaging bag was stored in an environment of 40 ° C. for 12 weeks.

  Next, a packaging bag containing hypochlorous acid inside and stored for 12 weeks and a packaging bag not containing hypochlorous acid inside are cut to a width of 15 mm, and each piece is pulled by a testing machine (Shimadzu Corporation The barrier layer 114 and the adhesive layer 115 were peeled off in the film flow direction of the packaging material at a speed of 50 mm / min. Using AGS-50D (trade name) manufactured by KK). Similarly, the adhesive layer 115 and the heat seal layer 116 were peeled in the film flow direction of the packaging material at a speed of 50 mm / min. This was performed for each of five samples, and the average value was used as the laminate strength (N / 15 mm). In addition, the packaging bag which put hypochlorous acid inside and was stored for 12 weeks measured only the lamination strength of the barrier layer 114 and the adhesive layer 115. After the measurement, when the laminate strength was 2 N / 15 mm or more, it was judged that the laminate strength was excellent (◎). Moreover, when the laminate strength was less than 2N / 15 mm, it was judged that the laminate strength was inferior (x). The results are shown in Table 2.

  As shown in Table 2, the packaging materials according to Examples 1 to 6 had high laminate strength between the adhesive layer 115 and the heat seal layer 116. Further, even after hypochlorous acid was put inside and stored for 12 weeks, the decrease in laminate strength was small.

  At this time, according to Examples 1 to 5, it was found that the barrier layer 114 and the heat seal layer 116 were bonded with high laminate strength by the adhesive layer 115 made of ethylene methacrylic acid copolymer and linear low density polyethylene. . Further, from Example 6 and Comparative Example 6, it was found that the barrier layer 114 and the heat seal layer 116 were bonded with high laminate strength by the adhesive layer 115 made of an ethylene methacrylic acid copolymer having a thickness of 25 μm or more. Further, the linear low density polyethylene and the ethylene methacrylic acid copolymer are hardly deteriorated even when hypochlorous acid is stored as the contents, and delamination is unlikely to occur between the barrier layer 114 and the heat seal layer 116. I understood it.

[Evaluation of quality retention performance for contents]
Evaluation of the quality maintenance performance with respect to the contents was carried out by forming a 10 cm × 10 cm packaging bag (heat seal width 1 cm) with the packaging material 110 according to Examples 1 to 6 and Comparative Examples 1 to 8, and then forming a 70 ° C. inside the packaging bag. The taste change of the contents was evaluated when filled with sake and when filled with distilled water. This was done by 10 investigators, and when more than 9 out of 10 evaluated that the contents did not have an odor caused by the adhesive or resin, it was judged that the quality retention performance for the contents was excellent (◎) . Moreover, when 6 or more out of 10 people evaluated that the contents did not have an odor caused by the adhesive or the resin, it was judged that the contents had a certain quality retention performance (◯). Moreover, when 5 or less out of 10 people evaluated that the contents had an odor caused by the adhesive or the resin, it was judged that the quality retention performance for the contents was poor (×). The results are shown in Table 3.

[Non-adsorptive evaluation]
Evaluation about non-adsorbability cuts the packaging material according to Examples 1 to 6 and Comparative Examples 1 to 8 to 10 cm × 10 cm, and then seals the packaging material 110 cut with 100 g of menthol in a glass container at 40 ° C. Stored for 1 week. At this time, the mass change before and after storage of the packaging material was measured. Moreover, when the mass change was less than +0.1 g, it was judged that the non-adsorption property was excellent (◎). Moreover, when mass change was +0.1 g or more and +0.5 g or less, it was judged that it has a fixed non-adsorption property ((circle)). Moreover, when mass change was larger than + 0.5g, it was judged that non-adsorption property was inferior (x). The results are shown in Table 3.

  As shown in Table 3, the packaging material 110 according to Examples 1 to 6 has high quality retention performance and high non-adsorbability because the heat seal layer 116 includes a cyclic olefin copolymer, as compared with Comparative Examples 2 and 3. I understood it.

  Further, when Example 2 and Example 5 are compared, the quality retention performance is higher when the thickness of the layer made of linear low density polyethylene disposed in the innermost layer of the heat seal layer 116 is 5 μm than when it is 10 μm. taller than. In addition, when Example 3 and Example 5 are compared, the thickness of the innermost layer of the heat seal layer 116 when a blend resin of a linear low density polyethylene having a thickness of 10 μm and a cyclic olefin copolymer is disposed. The quality retention performance is higher than when a layer made of linear low density polyethylene having a thickness of 10 μm is provided.

  This is presumably because when the layer made of linear low density polyethylene is formed thick, the odor component due to the linear low density polyethylene enters the contents. Therefore, the innermost layer of the heat seal layer 116 is a layer made of a linear low density polyethylene having a thickness of 5 μm or less or a layer made of a blend resin of a linear low density polyethylene having a thickness of 10 μm or less and a cyclic olefin copolymer. When the is formed, the quality retention performance can be further improved.

  In Examples 1 to 5, the melting point of the ethylene methacrylic acid copolymer forming the upper layer 115a of the adhesive layer 115 is 100 ° C. or lower. The melting point of the linear low density polyethylene forming the lower layer part 115b of Examples 1 to 3 and Example 5 is 100 ° C. or less, and the melting point of the linear low density polyethylene forming the lower layer part 115b of Example 4 is 121 ° C.

  For this reason, Examples 1 to 3 and 5 can melt-extrude the adhesive layer 115 at a lower temperature than Example 4, and Example 1 and Example in which the thermal adhesive layer 115 and the heat seal layer 116 have the same layer configuration. Compared with 4, the quality retention performance of Example 1 is higher. At this time, the density of the linear low-density polyethylene forming the lower layer part 115b of Example 1 is lower than that of Example 4.

Therefore, when the melting point of the ethylene methacrylic acid copolymer and the chain low density polyethylene forming the adhesive layer 115 is 100 ° C. or less, and the density of the chain low density polyethylene is less than 0.92 g / cm ³ , the quality is maintained. The performance can be further improved.

  Further, when the acid content of the ethylene methacrylic acid copolymer forming the upper layer portion 115a when the adhesive layer 115 is melt-extruded at a low temperature becomes 10% or more by mass percentage, the laminate strength of the adhesive layer 115 and the barrier layer 114 is increased. Decreases. For this reason, it is more desirable that the acid content of the ethylene methacrylic acid copolymer forming the upper layer portion 115a is less than 10% by mass (4% in Example 1).

  Similarly, in Example 6, the melting point of the ethylene methacrylic acid copolymer forming the adhesive layer 115 is 100 ° C. or less, and has high quality retention performance. Accordingly, it is more desirable that the ethylene methacrylic acid copolymer forming the adhesive layer 115 has a melting point of 100 ° C. or lower and an acid content of less than 10% by mass percentage.

  INDUSTRIAL APPLICABILITY The present invention can be used as a packaging material that constitutes a container for packaging non-alcoholic beverages such as juices, teas, coffee, milk beverages, and soups, alcoholic beverages such as sake and shochu, and menthol components.

DESCRIPTION OF SYMBOLS 10 Packaging container 11a, 11b Heat seal part 110 Packaging material 112 Base material layer 113 Adhesive agent 114 Barrier layer 115 Adhesive layer 115a Upper layer part 115b Lower layer part 116 Heat seal layer 117 Thermal adhesive resin layer

Claims (2)

  A packaging material in which at least a base material layer, a barrier layer having gas barrier properties, and a heat seal layer made of a heat-adhesive resin are sequentially laminated, the heat seal layer including a layer made of a cyclic olefin copolymer, The adhesive layer for bonding the barrier layer and the heat seal layer is composed of an ethylene methacrylic acid copolymer disposed on the barrier layer side and a linear low density polyethylene disposed on the heat seal layer side. Packaging material to do.   2. The packaging material according to claim 1, wherein the heat seal layer has a layer made of the cyclic olefin copolymer or a layer made of linear low-density polyethylene on a surface in contact with the adhesive layer.

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