Laminate, packaging bag, and packaging

Abstract

The present invention provides a laminate having a laminated structure comprising a base layer, an intermediate layer, and a sealant layer, in that order, wherein maximum aperture heights H1, H2 measured via a prescribed process meet the conditions below, and the loop stiffness value after heating at 128°C for 15 minutes is between 80 mN and 220 mN inclusive.　4 mm ≤ H1 6 mm ≤ H2

Description

Laminate, packaging bag, and packaging body

[0001] The present disclosure relates to a laminate, a packaging bag, and a packaging body.

[0002] Laminates are widely used as packaging materials for foods, pharmaceuticals, etc., which are subjected to heat sterilization such as boiling or retort treatment. Known examples of laminates include a biaxially oriented PET (polyethylene terephthalate) film, which has excellent heat resistance and toughness, and a polyolefin film, such as polyethylene or polypropylene, as a sealant layer (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2017-178357

[0004] Packaging materials are required to allow the contents contained therein to be easily discharged, and conventional laminates have room for improvement in terms of dischargeability.

[0005] Furthermore, packaging materials are required to have excellent handling properties when opened.

[0006] One aspect of the present disclosure provides a packaging bag and a package that are excellent in discharging properties and handling properties when opened. Another aspect of the present disclosure provides a laminate useful for producing such a packaging bag and a package.

[0007] In order to solve the above problems, the present disclosure provides the following laminate, packaging bag, and packaging body: [1] A laminate having a laminate structure including, in this order, a base layer, an intermediate layer, and a sealant layer, wherein the maximum opening heights H1 and H2 measured through the following steps satisfy the following conditions: 4 mm≦H1 6 mm≦H2 The maximum opening heights H1 and H2 are: (1a) preparing two of the laminates each having a width of 90 mm and a length of 140 mm as test pieces, (1b) overlapping the two test pieces with the sealant layers facing each other and sealing three sides with a seal width of 5 mm to form a bag, (1c) pouring 70 g of water into the upper end of the bag and then sealing the upper end with a seal width of 5 mm to obtain a test piece, and (1d) heating the test piece at a temperature of 128°C for 15 minutes at a pressure of 0.3 MPa. (1e) after step (1d), cutting the bag from one side to the other at a first position 20 mm from the top end of the bag, draining the water, and measuring the maximum opening height H1 at the first position with the bag placed on a horizontal table, and (1f) after step (1e), cutting the bag from one side to the other at a second position 50 mm from the first position and measuring the maximum opening height H2 at the second position with the bag placed on a horizontal table, and a loop stiffness value of 80 mN or more and 220 mN or less after heating at 128°C for 15 minutes. [2] The laminate according to [1], wherein, when heated at 128°C for 15 minutes, the MD heat shrinkage calculated by the following formula (1) is 1.0% or more and 3.0% or less, and the TD heat shrinkage calculated by the following formula (2) is 1.0% or more and 3.0% or less. MD heat shrinkage rate (%) = (MD length before heating - MD length after heating) / MD length before heating x 100 ... (1) TD heat shrinkage rate (%) = (TD length before heating - TD length after heating) / TD length before heating x 100 ... (2) [3] The laminate according to [1] or [2], wherein when heated at 128°C for 15 minutes, the sealant layer thermally expands in the MD and thermally shrinks in the TD. [4] The laminate according to [1] or [2], wherein the base material layer is heated at 128°C for 15 minutes, and the MD heat shrinkage rate calculated by the following formula (1) is S1 ＭＤThe thermal shrinkage rate of TD calculated by the following (2) is S1 ＴＤ When this is done, S1 ＭＤ and S1 ＴＤ The difference between (S1 ＭＤ -S1 ＴＤ [5] The laminate according to any one of [1] to [3], wherein the MD heat shrinkage (%) is greater than 0% and less than 5%. MD heat shrinkage (%) = (MD length before heating - MD length after heating) / MD length before heating x 100 ... (1) TD heat shrinkage (%) = (TD length before heating - TD length after heating) / TD length before heating x 100 ... (2) [6] The laminate according to any one of [1] to [3], wherein the intermediate layer has a second base material layer, and the second base material layer is heated at 128°C for 15 minutes, and the MD heat shrinkage calculated by the following formula (1) is S2 ＭＤ The thermal shrinkage rate of TD calculated by the following formula (2) is S2 ＴＤ When this is done, S2 ＭＤ and S2 ＴＤ The difference between (S2 ＭＤ -S2 ＴＤ) is more than 0% and not more than 5%. MD heat shrinkage (%) = (MD length before heating - MD length after heating) / MD length before heating x 100 ... (1) TD heat shrinkage (%) = (TD length before heating - TD length after heating) / TD length before heating x 100 ... (2) [6] The laminate according to any of [1] to [5], wherein the maximum opening heights H1 and H2 satisfy the following conditions: 4 mm ≦ H1 ≦ 7 mm 6 mm ≦ H2 ≦ 9 mm [7] The laminate according to any of [1] to [6], wherein the base material layer, the intermediate layer, and the sealant layer contain a polypropylene-based resin, and the total mass ratio of the polypropylene-based resin in the laminate is 90 mass% or more. [8] A packaging bag formed using the laminate according to any of [1] to [7]. [9] The packaging bag according to any of [1] to [8], which is used for applications that require heat treatment at 120°C or higher.

[10] A packaging bag; and contents accommodated in the packaging bag, wherein the packaging bag is formed using a laminate, and the laminate has a laminate structure including a base layer, an intermediate layer, and a sealant layer in this order, and the maximum opening heights H1 and H2 measured through the following steps satisfy the following conditions: 4 mm≦H1 6 mm≦H2 The maximum opening heights H1 and H2 are: (2a) a step of cutting the packaging bag from one side to the other at the first position, setting 20 mm from the top end of the packaging bag as a first position and the center of the packaging bag in the height direction as a second position, and after discharging the contents, placing the packaging bag on a horizontal table and measuring the maximum opening height H1 at the first position; (2b) after the step (2a), cutting the packaging bag from one side to the other at the second position, and placing the packaging bag on a horizontal table and measuring the maximum opening height H2 at the second position; and the loop stiffness value after heating the laminate at 128°C for 15 minutes is measured through the above-mentioned method, and is 80 mN or more and 220 mN or less.

[0008] According to one aspect of the present disclosure, there is provided a packaging bag and a package that are excellent in discharging properties and handling properties when opened. According to another aspect of the present disclosure, there is provided a laminate that is useful for producing such a packaging bag and a package.

[0009] Fig. 1 is a schematic cross-sectional view showing a laminate according to one embodiment. Fig. 2 is a schematic front view of an example of a package. Fig. 3 is an end view taken along imaginary line II in Fig. 2. Fig. 4 is a schematic view showing a method for measuring the thermal shrinkage rate during heating.

[0010] Hereinafter, embodiments of the present disclosure will be described. Note that the same components are denoted by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional ratios in the drawings are not limited to those shown in the drawings.

[0011] <Laminate> A laminate according to one embodiment will be described below. FIG. 1 is a schematic cross-sectional view showing a laminate according to this embodiment. The laminate 1 has a laminate structure including, in this order, a first base material layer 10, a first adhesive layer 20, an intermediate layer 30, a second adhesive layer 40, and a sealant layer 50. The maximum opening heights H1 and H2 measured through the following steps (1a) to (1f) satisfy the following conditions. When the maximum opening heights H1 and H2 satisfy the following conditions, the opening of a packaging bag obtained using the laminate 1 is difficult to close when the opening is positioned vertically downward to discharge the contents. Therefore, the packaging bag has excellent dischargeability even without additional processing such as providing irregularities on the surface of the sealant layer (innermost layer) of the laminate 1 to facilitate discharge of the contents. 4 mm≦H1 6 mm≦H2

[0012] (1a) A step of preparing two laminates each having a width of 90 mm and a length of 140 mm as test pieces; (1b) A step of overlapping the two test pieces with the sealant layers facing each other and sealing three sides with a seal width of 5 mm to form a bag; (1c) A step of pouring 70 g of water into the top end of the bag, and then sealing the top end with a seal width of 5 mm to obtain a test piece; (1d) A step of heating the test piece under conditions of a temperature of 128°C, a time of 15 minutes, and a pressure of 0.3 MPa; (1e) After the step (1d), a step of cutting the bag from one side to the other at a first position 20 mm from the top end of the bag, draining the water, and measuring the maximum opening height H1 at the first position while the bag is placed on a horizontal table; (1f) After the step (1e), a step of cutting the bag from one side to the other at a second position 50 mm from the first position, and measuring the maximum opening height H2 at the second position while the bag is placed on a horizontal table.

[0013] The maximum opening heights H1 and H2 are the maximum distance between the inner edges of the sealant layers.

[0014] The maximum opening height H1 is preferably 4.3 mm or more, and more preferably 5.0 mm or more, because this provides better dischargeability. The maximum opening height H1 may be 7.0 mm or less. The maximum opening height H1 may be 4 mm or more and 7.0 mm or less, 4.3 mm or more and 7.0 mm or less, or 5.0 mm or more and 7.0 mm or less.

[0015] The maximum opening height H2 is preferably 6.3 mm or more, and more preferably 7.0 mm or more, because this allows air to easily enter the entire main body of the packaging bag and improves the ease of separation of the contents located at the square corners of the main body. The maximum opening height H2 may be 9.0 mm or less. The maximum opening height H2 may be 6.0 mm or more and 9.0 mm or less, 6.3 mm or more and 9.0 mm or less, or 7.0 mm or more and 9.0 mm or less.

[0016] The maximum opening heights H1 and H2 can be changed, for example, by adjusting the thermal shrinkage rates of the first base material layer and the second base material layer.

[0017] When the laminate 1 is heated at 128°C for 15 minutes, the MD heat shrinkage rate calculated by the following formula (1) is preferably 1.0% or more, and more preferably 1.8% or more, because the resulting packaging bag opens sufficiently and has even better discharging properties. When the laminate 1 is heated at 128°C for 15 minutes, the MD heat shrinkage rate calculated by the following formula (1) is preferably 3.0% or less, from the viewpoint of suppressing poor appearance and conveyance defects. When the laminate 1 is heated at 128°C for 15 minutes, the MD heat shrinkage rate calculated by the following formula (1) may be 1.0% or more and 3.0% or less, or 1.8% or more and 3.0% or less.

[0018] When laminate 1 is heated at 128°C for 15 minutes, the TD heat shrinkage rate calculated by the following formula (2) is preferably 1.0% or more, and more preferably 1.8% or more, because the resulting packaging bag opens sufficiently and has even better discharging properties. When laminate 1 is heated at 128°C for 15 minutes, the TD heat shrinkage rate calculated by the following formula (2) is preferably 3.0% or less, from the viewpoint of suppressing poor appearance and poor conveyance due to shrinkage during bag formation. When laminate 1 is heated at 128°C for 15 minutes, the TD heat shrinkage rate calculated by the following formula (2) may be 1.0% or more and 3.0% or less, or 1.8% or more and 3.0% or less.

[0019] MD heat shrinkage rate (%) = (MD length before heating - MD length after heating) / MD length before heating x 100 (1) TD heat shrinkage rate (%) = (TD length before heating - TD length after heating) / TD length before heating x 100 (2)

[0020] MD is the machine direction of the substrate layer and sealant layer, and TD is the transverse direction perpendicular to the machine direction. The orientation angle of the film can be measured using, for example, a retardation measuring device (trade name: KOBRA, manufactured by Oji Scientific Instruments Co., Ltd.), and the MD and TD can be distinguished from the orientation angle. For example, when the film is a sequentially biaxially oriented polypropylene film, the direction in which the molecular chains are oriented is considered to be TD.

[0021] The loop stiffness value of the laminate 1 after heating at 128°C for 15 minutes is preferably 80 mN or more, more preferably 90 mN or more, preferably 220 mN or less, more preferably 170 mN or less, even more preferably 150 mN or less, even more preferably 130 mN or less, and particularly preferably 105 mN or less. A loop stiffness value within this range provides excellent handling when opening the packaging bag. When the loop stiffness value is 80 mN or more, the packaging bag is less likely to twist (twist) when the contents are removed by holding both sides of the packaging bag with both hands and pushing toward the center of the packaging bag, making it easy to open and maintaining the opened shape. Therefore, the packaging bag tends to have even better ejection properties. When the loop stiffness value is 150 mN or less, it is easier to hold both sides of the packaging bag with both hands and push toward the center of the packaging bag. Therefore, the packaging bag tends to be easy to open stably and has even better ejection properties. Furthermore, the packaging bag can be easily opened with a light force and easily maintains its opened shape. The loop stiffness value of the laminate 1 after heating at 128°C for 15 minutes may be 80 mN or more and 220 mN or less, 80 mN or more and 170 mN or less, 80 mN or more and 150 mN or less, 80 mN or more and 130 mN or less, 80 mN or more and 105 mN or less, 90 mN or more and 220 mN or less, 90 mN or more and 170 mN or less, 90 mN or more and 150 mN or less, 90 mN or more and 130 mN or less, or 90 mN or more and 105 mN or less. The loop stiffness value can be measured by the method described in the Examples below.

[0022] The loop stiffness value is a physical property that indicates the rigidity of a film. The loop stiffness value increases somewhat due to thermal shrinkage after heating, but can be adjusted by the film thickness of the laminate and the crystallinity and Young's modulus of each layer. The larger the film thickness, the larger the loop stiffness value tends to be. The higher the crystallinity, the larger the loop stiffness value tends to be. The higher the Young's modulus, the larger the loop stiffness value tends to be. Conversely, the smaller the film thickness, the smaller the loop stiffness value tends to be. The lower the crystallinity, the smaller the loop stiffness value tends to be. The lower the Young's modulus, the smaller the loop stiffness value tends to be.

[0023] The total mass proportion of the polypropylene-based resin in the laminate 1 is preferably 90 mass% or more based on the total amount of the laminate 1, because the laminate 1 serves as a packaging material made of a single material (monomaterial) and has excellent recyclability. The content of the polypropylene-based resin in the laminate 1 may be 92.5 mass% or more, or may be 95 mass% or more, based on the total amount of the laminate 1.

[0024] Each layer of the laminate 1 will be described in detail below.

[0025] [First base layer 10] The first base layer 10 is a plastic member that functions as the outermost layer in the laminate 1. The thickness of the first base layer 10 is not particularly limited. Depending on the application, the thickness can be set to 6 to 200 μm, but from the viewpoint of reducing materials to reduce the environmental load and from the viewpoint of obtaining excellent heat resistance, impact resistance, and excellent gas barrier properties, the thickness may be 9 to 50 μm, 12 to 38 μm, 18 to 30 μm, or 15 to 30 μm.

[0026] The first base layer 10 is, for example, a polyolefin film from the viewpoint of the recyclability of the laminate 1. The first base layer 10 may contain or consist of a polypropylene film. The polypropylene film may be an acid-modified polypropylene film obtained by graft-modifying polypropylene with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like. Furthermore, polypropylene-based resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer can be used as the polypropylene.

[0027] The polypropylene film constituting the first base layer 10 may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent.

[0028] The polypropylene film constituting the first base layer 10 may be a stretched film or a non-stretched film. The polypropylene film is preferably a stretched polypropylene film because it has better dischargeability.

[0029] When the first base material layer is heated at 128°C for 15 minutes, the MD heat shrinkage calculated by the above formula (1) is preferably 2.0% or more, more preferably 3.0% or more, and even more preferably 4.0% or more, in order to achieve better discharging properties. From the viewpoint of handleability when opening the packaging bag, the MD heat shrinkage may be 5.0% or less.

[0030] When the first base material layer is heated at 128°C for 15 minutes, the heat shrinkage rate in the TD calculated by the above formula (2) is preferably more than 0%, more preferably 1.0% or more, and even more preferably 2.0% or more, in order to achieve better discharging properties. From the viewpoint of handleability when opening the packaging bag, the heat shrinkage rate in the TD may be 3.0% or less.

[0031] The first base material layer is heated at 128°C for 15 minutes, and the MD heat shrinkage rate calculated by the above formula (1) is S1 ＭＤ The thermal shrinkage rate of TD calculated by the above formula (2) is S1 ＴＤ When this is done, S1 ＭＤ and S1 ＴＤ The difference between (S1 ＭＤ -S1 ＴＤ From the viewpoint that the opening height tends to be increased and discharging properties tend to be further improved, the S1 is preferably more than 0%, more preferably 1% or more, and even more preferably 1.5% or more, and from the viewpoint of suppressing distortion of the packaging bag that causes packaging defects, the S1 is preferably 5% or less, more preferably 4% or less, and even more preferably 3% or less. ＭＤ and S1 ＴＤ The difference between (S1 ＭＤ -S1 ＴＤ ) may be greater than 0% and less than or equal to 5%, greater than 0% and less than or equal to 4%, greater than 0% and less than or equal to 3%, 1% or more and less than or equal to 5%, 1% or more and less than or equal to 4%, 1% or more and less than or equal to 3%, 1.5% or more and less than or equal to 5%, 1.5% or more and less than or equal to 4%, or 1.5% or more and less than or equal to 3%.

[0032] The first base material layer is heated at 128°C for 15 minutes, and the MD heat shrinkage rate calculated by the above formula (1) is S1 ＭＤ When the second base material layer is heated at 128°C for 15 minutes, the MD heat shrinkage rate calculated by the above formula (1) is S2 ＭＤ When this is done, S1 ＭＤ and S2 ＭＤ The difference between (S1 ＭＤ -S2 ＭＤ ) is preferably more than 0%, more preferably 0.25% or more, and even more preferably 0.5% or more, from the viewpoint of easily increasing the opening height and providing even better discharge properties, and is preferably 2.5% or less, more preferably 2.0% or less, and even more preferably 1.0% or less, from the viewpoint of suppressing the occurrence of cracks in the gas barrier layer due to differences in base shrinkage.

[0033] The first base material layer is heated at 128°C for 15 minutes, and the thermal shrinkage rate in the TD calculated by the above formula (2) is S1 ＴＤ When the second base material layer is heated at 128°C for 15 minutes, the thermal shrinkage rate in the TD calculated by the above formula (2) is S2 ＴＤ When this is done, S1 ＴＤ and S2 ＴＤ The difference between (S1 ＴＤ -S2 ＴＤ ) is preferably more than 0%, more preferably 0.3% or more, and even more preferably 0.4% or more, from the viewpoint of easily increasing the opening height and providing more excellent discharge properties, and is preferably 2.0% or less, more preferably 1.5% or less, and even more preferably 1.0% or less, from the viewpoint of suppressing the occurrence of cracks in the gas barrier layer due to differences in base shrinkage.

[0034] The surface of the first base material layer 10 to be laminated may be subjected to various pretreatments such as corona treatment, plasma treatment, and flame treatment, or may be provided with a coating layer such as an easy-adhesion layer.

[0035] [First Adhesive Layer 20 and Second Adhesive Layer 40] The first adhesive layer 20 is a layered member that bonds the first base material layer 10 and the intermediate layer 30. The second adhesive layer 40 is a layered member that bonds the intermediate layer 30 and the sealant layer 50. Examples of adhesive materials that can be used for the first adhesive layer 20 and the second adhesive layer 40 include polyester-isocyanate resins, urethane resins, and polyether resins. For packaging bags used in retort applications, a two-component curing urethane adhesive that is retort-resistant is preferably used. From an environmental perspective, the adhesive does not need to contain 3-glycidyloxypropyltrimethoxysilane (GPTMS). The first adhesive layer 20 and the second adhesive layer 40 do not need to contain chlorine. In this case, the first adhesive layer 20 and the second adhesive layer 40 can suppress discoloration of recycled resins and odor generation due to heat treatment after recycling. From the viewpoint of environmental consideration, the first adhesive layer 20 and the second adhesive layer 40 may be formed from a biomass material and may not contain a solvent.

[0036] The urethane adhesive contains a polyol and a polyisocyanate. When a urethane adhesive is used, the first adhesive layer 20 and the second adhesive layer 40 may contain polyurethane obtained by curing the urethane adhesive, or may contain an uncured urethane adhesive.

[0037] Polyols have two or more hydroxyl groups in one molecule. Polyisocyanates have two or more isocyanate groups in one molecule. Polyols and polyisocyanates may react as a base resin and a curing agent, respectively, to produce polyurethane.

[0038] The polyol may contain at least one selected from the group consisting of polyester polyols and polyether polyols.

[0039] The polyisocyanate may be used alone or in combination of two or more thereof. Examples of the polyisocyanate include an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, and an aromatic polyisocyanate compound.

[0040] The thickness of the first adhesive layer 20 is, for example, 0.5 μm or more and 10 μm or less. When the thickness of the first adhesive layer 20 is 0.5 μm or more, peeling between the first base material layer 10 and the intermediate layer 30 can be effectively suppressed. When the thickness of the first adhesive layer 20 is 10 μm or less, the laminate 1 can be easily made into a monomaterial. The thickness of the first adhesive layer 20 may be 1 μm or more, 2 μm or more, 8 μm or less, 6 μm or less, or 5 μm or less.

[0041] The thickness of the second adhesive layer 40 is, for example, 0.5 μm or more and 10 μm or less. When the thickness of the second adhesive layer 40 is 0.5 μm or more, peeling between the intermediate layer 30 and the sealant layer 50 can be effectively suppressed. When the thickness of the second adhesive layer 40 is 10 μm or less, the laminate 1 can be easily made into a monomaterial. The thickness of the first adhesive layer 20 may be 1 μm or more, 2 μm or more, 8 μm or less, 6 μm or less, or 5 μm or less.

[0042] 1 , the intermediate layer 30 has a second base layer 31 and a gas barrier layer 32. The gas barrier layer 32 exhibits gas barrier properties against gases such as water vapor and oxygen. The gas barrier layer 32 has, from the second base layer 31 side, an anchor coat layer 32 a, a vapor deposition layer 32 b, and a barrier coat layer 32 c, in this order.

[0043] The thickness of the intermediate layer may be the same as that of the first substrate layer 10 .

[0044] (Second substrate layer 31) The thickness of the second substrate layer 31 may be the same as that of the first substrate layer 10. From the viewpoint of the recyclability of the laminate 1, the second substrate layer 31 is, for example, a polyolefin film. The second substrate layer 31 may contain a polypropylene film or may be made of a polypropylene film. The polypropylene film may be the same as that of the first substrate layer 10. The polypropylene film may be added with various additives similar to those of the first substrate layer 10. When the second substrate layer 31 contains an antiblocking agent, the addition of the antiblocking agent may be suppressed to improve the smoothness of the surface on which the vapor deposition layer 32b is provided. The second substrate layer 31 may be subjected to various pretreatments similar to those of the first substrate layer 10, or may be provided with a coating layer.

[0045] When the second base material layer is heated at 128°C for 15 minutes, the MD heat shrinkage calculated by the above formula (1) is preferably 1.0% or more, more preferably 2.0% or more, and even more preferably 3.0% or more, in order to achieve better discharging properties. The MD heat shrinkage may be 5.0% or less, in terms of handleability when opening the packaging bag.

[0046] When the second base material layer is heated at 128°C for 15 minutes, the TD heat shrinkage calculated by the above formula (2) is preferably more than 0%, more preferably 1.0% or more, and even more preferably 2.0% or more, in order to achieve better discharging properties. The TD heat shrinkage may be 3.0% or less in terms of handleability when opening the packaging bag.

[0047] The second base material layer is heated at 128°C for 15 minutes, and the MD heat shrinkage rate calculated by the above formula (1) is S2 ＭＤ The thermal shrinkage rate of TD calculated by the above formula (2) is S2 ＴＤ When this is done, S2 ＭＤ and S2 ＴＤ The difference between (S2 ＭＤ -S2 ＴＤFrom the viewpoint that the opening height tends to be increased and discharging properties tend to be further improved, the S2 is preferably more than 0%, more preferably 1% or more, and even more preferably 1.5% or more, and from the viewpoint of suppressing distortion of the packaging bag that causes packaging defects, the S2 is preferably 5% or less, more preferably 4% or less, and even more preferably 3% or less. ＭＤ and S2 ＴＤ The difference between (S2 ＭＤ -S2 ＴＤ ) may be greater than 0% and less than or equal to 5%, greater than 0% and less than or equal to 4%, greater than 0% and less than or equal to 3%, 1% or more and less than or equal to 5%, 1% or more and less than or equal to 4%, 1% or more and less than or equal to 3%, 1.5% or more and less than or equal to 5%, 1.5% or more and less than or equal to 4%, or 1.5% or more and less than or equal to 3%.

[0048] (Anchor Coat Layer 32a) The anchor coat layer 32a functions as a layer that can improve the adhesion performance of the vapor deposition layer 32b on the second substrate layer 31, and is provided directly on the second substrate layer 31. Therefore, the anchor coat layer 32a is located between the second substrate layer 31 and the vapor deposition layer 32b. By providing the anchor coat layer 32a, the smoothness of the surface on which the vapor deposition layer 32b is provided in the intermediate layer 30 can be improved. Note that improved smoothness makes it easier to form the vapor deposition layer 32b uniformly without defects, and makes it easier to exhibit high barrier properties. The anchor coat layer 32a can be formed using, for example, an anchor coating agent.

[0049] As the anchor coating agent, a urethane resin is preferred. Examples of urethane resins include polyester-based polyurethane resins, polyether-based polyurethane resins, and acrylic-based polyurethane resins. As the anchor coating agent, polyester-based polyurethane resins and acrylic-based urethane resins are preferred from the viewpoints of heat resistance and interlayer adhesive strength. In particular, for packaging materials that undergo boiling or retorting treatment, an acrylic-based polyurethane resin is more preferred as the anchor coating agent.

[0050] The thickness of the anchor coat layer 32a is not particularly limited, but is preferably in the range of 0.01 to 5 μm, more preferably in the range of 0.03 to 3 μm, and particularly preferably in the range of 0.05 to 2 μm. If the thickness of the anchor coat layer 32a is equal to or greater than the lower limit, more sufficient interlayer adhesive strength tends to be obtained, while if the thickness is equal to or less than the upper limit, desired gas barrier properties tend to be easily exhibited.

[0051] As a method for applying the anchor coat layer 32a onto the second substrate layer 31, known application methods can be used without any particular limitation, and examples thereof include immersion (dipping), spraying, methods using a coater, a printing machine, a brush, etc. In addition, examples of the types of coaters and printing machines used in these methods and the application methods thereof include gravure coaters such as direct gravure, reverse gravure, kiss reverse gravure, and offset gravure, reverse roll coaters, microgravure coaters, coaters with chamber doctor, air knife coaters, dip coaters, bar coaters, comma coaters, and die coaters.

[0052] The amount of the anchor coating layer 32a applied is 1 m after the anchor coating agent is applied and dried. ２ Mass per unit is 0.01 to 5 g / m ２ It is preferable that the density is 0.03 to 3 g / m ２ It is more preferable that the thickness of the anchor coating agent is 1 m after it is applied and dried. ２ When the mass per unit area is equal to or greater than the lower limit, film formation tends to be sufficient, whereas when the mass per unit area is equal to or less than the upper limit, the film tends to be sufficiently dried and the solvent tends not to remain.

[0053] The method for drying the anchor coat layer 32a is not particularly limited, but examples thereof include natural drying, drying in an oven set at a predetermined temperature, and using a dryer attached to the coater, such as an arch dryer, floating dryer, drum dryer, infrared dryer, etc. Furthermore, the drying conditions can be appropriately selected depending on the drying method, and for example, in the method of drying in an oven, it is preferable to dry at a temperature of 60 to 100°C for about 1 second to 2 minutes.

[0054] Instead of the polyurethane resin, a polyvinyl alcohol resin can be used for the anchor coat layer 32a. The polyvinyl alcohol resin may be any resin having a vinyl alcohol unit formed by saponifying a vinyl ester unit, such as polyvinyl alcohol (PVA) or ethylene-vinyl alcohol copolymer (EVOH).

[0055] Examples of PVA include resins obtained by homopolymerizing vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate, followed by saponification. The PVA may also be a modified PVA that has been copolymerized or post-modified. The modified PVA can be obtained, for example, by copolymerizing a vinyl ester with an unsaturated monomer copolymerizable with the vinyl ester, followed by saponification. Examples of unsaturated monomers copolymerizable with vinyl esters include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxy group-containing α-olefins such as 3-buten-1-ol, 4-pentyn-1-ol, and 5-hexen-1-ol; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and undecylenic acid; nitriles such as acrylonitrile and methacrylonitrile; diacetone acrylamide, acrylic acid, and the like. olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid; vinyl compounds such as alkyl vinyl ethers, dimethyl allyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxane, glycerin monoallyl ether, and 3,4-diacetoxy-1-butene; vinylidene chloride, 1,4-diacetoxy-2-butene, and vinylene carbonate.

[0056] The degree of polymerization of PVA is preferably 300 to 3000. If the degree of polymerization is less than 300, the barrier properties tend to decrease, while if it exceeds 3000, the viscosity becomes too high and the coatability tends to decrease. The saponification degree of PVA is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. The saponification degree of PVA may be 100 mol% or less, or may be 99.9 mol% or less. The polymerization degree and saponification degree of PVA can be measured in accordance with the method described in JIS K 6726 (1994).

[0057] EVOH is generally obtained by saponifying a copolymer of ethylene and an acid vinyl ester such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, or vinyl versatate.

[0058] The degree of polymerization of EVOH is preferably 300 to 3,000. If the degree of polymerization is less than 300, the barrier properties tend to decrease, while if it exceeds 3,000, the viscosity becomes too high and the coatability tends to decrease. The degree of saponification of the vinyl ester component of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. The degree of saponification of EVOH may be 100 mol% or less, or 99.9 mol% or less. The degree of saponification of EVOH is determined by nuclear magnetic resonance (1H-NMR) measurement, from the peak area of ​​hydrogen atoms contained in the vinyl ester structure and the peak area of ​​hydrogen atoms contained in the vinyl alcohol structure.

[0059] The ethylene unit content of EVOH is 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more. The ethylene unit content of EVOH is preferably 65 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. When the ethylene unit content is 10 mol% or more, good gas barrier properties or dimensional stability can be maintained under high humidity conditions. On the other hand, when the ethylene unit content is 65 mol% or less, good gas barrier properties can be achieved. The ethylene unit content of EVOH can be determined by NMR.

[0060] When a polyvinyl alcohol resin is used as the anchor coat layer 32a, the anchor coat layer 32a can be formed by coating a polyvinyl alcohol resin solution, multi-layer extrusion, or the like.

[0061] (Vapor-Deposited Layer 32b) The vapor-deposited layer 32b is a layer (gas barrier layer) that exhibits gas barrier properties against water vapor and oxygen and contains at least one of a metal and an inorganic oxide. The vapor-deposited layer 32b is provided directly on the anchor coat layer 32a. The vapor-deposited layer 32b may have a single-layer structure or a laminated structure. Therefore, the vapor-deposited layer 32b contains at least one of a metal vapor-deposited layer and an inorganic oxide layer. When the vapor-deposited layer 32b includes a metal vapor-deposited layer, examples of the metal contained in the metal vapor-deposited layer include aluminum and stainless steel. When the vapor-deposited layer 32b includes an inorganic oxide layer, examples of the inorganic oxide contained in the inorganic oxide layer include aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. From the viewpoints of transparency and barrier properties, the inorganic oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, from the viewpoint of excellent tensile elongation during processing, it is preferable that the inorganic oxide layer be a layer using silicon oxide. By using an inorganic oxide layer, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the laminate 1.

[0062] When the vapor-deposited layer 32b is an inorganic oxide layer using silicon oxide, the O / Si ratio of the inorganic oxide layer is preferably 1.7 or higher. An O / Si ratio of 1.7 or higher suppresses the content of metallic Si, making it easier to achieve good transparency. Furthermore, the O / Si ratio is preferably 2.0 or lower. An O / Si ratio of 2.0 or lower increases the crystallinity of SiO, preventing the inorganic oxide layer from becoming too hard and providing good tensile strength. This prevents cracks from occurring in the inorganic oxide layer when the barrier coat layer 32c is laminated. Furthermore, even after forming into a packaging bag, the first base layer 10 may shrink due to heat during boiling or retort treatment. However, an O / Si ratio of 2.0 or lower allows the inorganic oxide layer to easily adapt to this shrinkage, thereby preventing a decrease in barrier properties. To fully achieve these effects, the O / Si ratio of the inorganic oxide layer is preferably 1.75 or higher and 1.9 or lower, and more preferably 1.8 or higher and 1.85 or lower.

[0063] When the vapor-deposited layer 32b is an inorganic oxide layer using silicon oxide, the O / Si ratio of the inorganic oxide layer can be determined by X-ray photoelectron spectroscopy (XPS). For example, the measurement can be performed using an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV) with a non-monochromated MgKα (1253.6 eV) X-ray source and an X-ray output of 100 W (10 kV-10 mA). For quantitative analysis to determine the O / Si ratio, relative sensitivity factors of 2.28 for O1s and 0.9 for Si2p can be used.

[0064] The thickness of the vapor-deposited layer 32b is, for example, 5 nm or more and 80 nm or less. When the thickness of the vapor-deposited layer 32b is 5 nm or more, sufficient water vapor barrier properties can be obtained. Furthermore, when the thickness of the vapor-deposited layer 32b is 80 nm or less, cracks caused by deformation due to internal stress in the thin film can be suppressed, and a decrease in water vapor barrier properties can be suppressed. Note that a thickness of the vapor-deposited layer 32b exceeding 80 nm is undesirable from an economic standpoint, as costs are likely to increase due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the thickness of the vapor-deposited layer 32b may be 20 nm or more and 40 nm or less.

[0065] The deposition layer 32b can be formed by, for example, vacuum deposition. Vacuum deposition can be performed using physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition include, but are not limited to, vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD, plasma CVD, and photo-CVD.

[0066] In the vacuum film formation, resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, plasma enhanced chemical vapor deposition (PECVD), and the like are particularly preferably used. However, in terms of productivity, vacuum deposition is currently the most superior. As a heating means for vacuum deposition, it is preferable to use any of the electron beam heating method, resistance heating method, and induction heating method.

[0067] (Barrier Coat Layer 32c) The barrier coat layer 32c is a coating layer (gas barrier coating layer) having gas barrier properties and is provided on the vapor deposition layer 32b. The barrier coat layer 32c is a layer formed using a composition for forming a gas barrier coating layer (hereinafter also referred to as a coating agent) containing at least one selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide, a silane coupling agent, and a hydrolyzate thereof, for example.

[0068] From the viewpoint of more adequately maintaining gas barrier properties after hot water treatment such as retort treatment, the coating agent preferably contains at least a silane coupling agent or a hydrolyzate thereof, more preferably contains at least one selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide, and their hydrolyzates, and a silane coupling agent or a hydrolyzate thereof, and even more preferably contains a hydroxyl group-containing polymer compound or a hydrolyzate thereof, a metal alkoxide or a hydrolyzate thereof, and a silane coupling agent or a hydrolyzate thereof. The coating agent can be prepared, for example, by mixing a metal alkoxide and a silane coupling agent directly, or after having been previously treated by hydrolysis, with a solution obtained by dissolving a hydroxyl group-containing polymer compound, which is a water-soluble polymer, in an aqueous solvent (water or a water / alcohol mixture).

[0069] The components contained in the coating agent for forming the barrier coat layer 32c will be described in detail. Examples of hydroxyl group-containing polymer compounds used in the coating agent include polyvinyl alcohol, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate. Among these, polyvinyl alcohol (PVA) is preferred for use in the coating agent for the barrier coat layer 32c because it has particularly excellent gas barrier properties.

[0070] From the viewpoint of obtaining excellent gas barrier properties, the barrier coat layer 32c is preferably formed from a composition containing at least one selected from the group consisting of metal alkoxides represented by the following general formula (I) and hydrolysates thereof: M(OR１ ) ｍ (R ２ ) ｎ－ｍ ...(I) In the above general formula (I), R １ and R ２ are each independently a monovalent organic group having 1 to 8 carbon atoms, and are preferably an alkyl group such as a methyl group or an ethyl group. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer from 1 to n. １ or R ２ If there are multiple １ Comrades or R ２ They may be the same or different.

[0071] Specific examples of metal alkoxides include tetraethoxysilane [Si(OC ２ H ５ ) ４ ], triisopropoxyaluminum [Al(OC ３ H ７ ) ３ Tetraethoxysilane and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.

[0072] Examples of the silane coupling agent include compounds represented by the following general formula (II): Si(OR １１ ) ｐ (R １２ ) ３－ｐ R １３ ... (II) In the above general formula (II), R １１ represents an alkyl group such as a methyl group or an ethyl group, and R １２ represents a monovalent organic group such as an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an alkyl group substituted with an acryloxy group, or an alkyl group substituted with a methacryloxy group, and R １３ represents a monovalent organic functional group, and p represents an integer of 1 to 3. １１ or R １２ If there are multiple １１ Comrades or R １２ R may be the same or different. １３Examples of the monovalent organic functional group represented by the formula (I) include a monovalent organic functional group containing a glycidyloxy group, an epoxy group, a mercapto group, a hydroxyl group, an amino group, an alkyl group substituted with a halogen atom, or an isocyanate group.

[0073] Specific examples of the silane coupling agent include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane.

[0074] The silane coupling agent may also be a polymer formed by polymerization of the compound represented by the general formula (II). A trimer is preferred as the polymer, and 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is more preferred. This is a condensation polymer of 3-isocyanatoalkylalkoxysilane. It is known that 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate loses chemical reactivity in the isocyanate moiety, but the reactivity is ensured by the polarity of the nurate moiety. It is generally added to adhesives, similar to 3-isocyanatoalkylalkoxysilane, and is known as an adhesion improver. Therefore, adding 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate to a hydroxyl group-containing polymer compound can improve the water resistance of a gas barrier coating layer through hydrogen bonding. While 3-isocyanate alkyl alkoxysilanes have high reactivity and low liquid stability, 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurates are not water-soluble due to the polarity of the nurate moiety, but are easily dispersed in aqueous solutions and can maintain stable liquid viscosity. Furthermore, the water resistance of 3-isocyanate alkyl alkoxysilanes and 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurates is equivalent.

[0075] Some 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurates are produced by thermal condensation of 3-isocyanatepropylalkoxysilane, and may contain the raw material 3-isocyanatepropylalkoxysilane, but this does not pose any particular problems. 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate is more preferred, and 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate is even more preferred. 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate is practically advantageous because the methoxy group has a fast hydrolysis rate and those containing a propyl group are available relatively inexpensively.

[0076] Furthermore, known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity adjuster, and a colorant can be added to the coating agent as needed, provided that the gas barrier properties are not impaired.

[0077] The thickness of the barrier coat layer 32c is preferably 50 to 1000 nm, and more preferably 100 to 500 nm. If the thickness of the barrier coat layer 32c is 50 nm or more, more sufficient gas barrier properties tend to be obtained, and if it is 1000 nm or less, sufficient flexibility tends to be maintained.

[0078] The coating liquid for forming the barrier coat layer 32c can be applied by, for example, dipping, roll coating, gravure coating, reverse gravure coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset, etc. The coating film obtained by applying this coating liquid can be dried by, for example, hot air drying, hot roll drying, high frequency irradiation, infrared irradiation, UV irradiation, or a combination thereof.

[0079] The temperature at which the coating film is dried can be, for example, 50 to 150° C., and preferably 70 to 100° C. By setting the drying temperature within the above range, the occurrence of cracks in the vapor deposition layer 32 b and the barrier coat layer 32 c can be further suppressed, and excellent barrier properties can be achieved.

[0080] The barrier coat layer 32c may be formed using a coating agent containing a polyvinyl alcohol resin and a silane compound. The coating agent may contain an acid catalyst, an alkali catalyst, a photopolymerization initiator, etc., as needed.

[0081] The polyvinyl alcohol resin is as described above. Examples of the silane compound include a silane coupling agent, polysilazane, and siloxane, and specific examples thereof include tetramethoxysilane, tetraethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, and hexamethyldisilazane.

[0082] [Sealant Layer 50] The sealant layer 50 is a layer that provides heat-sealing properties to the laminate 1. From the viewpoint of the recyclability of the laminate 1, the sealant layer 50 is a polyolefin film, similar to the first base material layer 10. In this embodiment, the sealant layer 50 has a single-layer structure and is a resin layer made primarily of polypropylene, but is not limited to this. The sealant layer 50 may include a polypropylene film or may be made of a polypropylene film.

[0083] The polypropylene film may be an acid-modified polypropylene film obtained by graft-modifying polypropylene with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, etc. Furthermore, as the polypropylene, a polypropylene-based resin such as a homopolypropylene resin (PP), a propylene-ethylene random copolymer, a propylene-ethylene block copolymer, or a propylene-α-olefin copolymer can be used.

[0084] The polypropylene film constituting the sealant layer 50 is preferably a non-oriented polypropylene film from the viewpoint of improving the sealing properties by heat sealing.

[0085] The polypropylene film constituting the sealant layer 50 may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent.

[0086] The thickness of the sealant layer 50 is determined depending on the mass of the contents, the shape of the packaging bag, etc., but may be approximately 30 to 150 μm thick, or may be 50 to 80 μm thick.

[0087] When the sealant layer 50 is heated at 128°C for 15 minutes, it thermally expands in the MD and thermally shrinks in the TD, although the reason is unclear, which makes it easy to obtain the opening height of the packaging bag. From the same viewpoint, when the sealant layer 50 is heated at 128°C for 15 minutes, the MD heat shrinkage rate calculated by the above formula (1) is preferably -1.0% or more, more preferably -0.5% or more, and preferably less than 0%.

[0088] When the sealant layer 50 is heated at 128° C. for 15 minutes, the TD heat shrinkage calculated by the above formula (2) is preferably 0% or more and 1.0% or less.

[0089] The sealant layer 50 can be laminated by any known method, such as a dry lamination method in which a film-like sealant layer made of the above-mentioned polypropylene is laminated with an adhesive such as a one-component curing or two-component curing urethane adhesive, a non-solvent lamination method in which a film-like sealant layer is laminated using a solvent-free adhesive, or an extrusion lamination method in which the above-mentioned polypropylene is heated and melted, extruded into a curtain shape, and laminated.

[0090] Among the above lamination methods, the dry lamination method is preferred because it has high resistance to retort treatment, particularly high-temperature hot water treatment at 120° C. or higher. On the other hand, if the packaging bag is used for an application in which it will be treated at a temperature of 85° C. or lower, the lamination method is not particularly limited.

[0091] Although the laminate according to one embodiment has been described above, the laminate according to the present disclosure is not limited to the above embodiment. For example, the laminate may further include a printed layer.

[0092] [Printed Layer] The printed layer can be provided, for example, on at least one surface of the first base layer 10. The printed layer is provided in a position visible from the outside of the laminate 1 for the purpose of displaying information about the contents, identifying the contents, improving concealment, or improving the design of the packaging bag. The printing method and printing ink are not particularly limited, and are appropriately selected from known printing methods and printing inks taking into consideration printability on the film, design such as color tone, adhesion, safety as a food container, and the like. Examples of printing methods that can be used include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. Among these, gravure printing is preferably used from the viewpoints of productivity and high resolution of the image.

[0093] In order to improve the adhesion of the printed layer, the surface of the layer on which the printed layer is to be formed may be subjected to various pretreatments such as corona treatment, plasma treatment, and flame treatment, or a coating layer such as an easy-adhesion layer may be formed.

[0094] Furthermore, the laminate of the present disclosure may not include the anchor coat layer 32a. The laminate of the present disclosure may not include the barrier coat layer 32c. The stacking order of the second substrate layer 31, the anchor coat layer 32a, the vapor deposition layer 32b, and the barrier coat layer 32c may be reversed. Furthermore, the laminate of the present disclosure may not include at least one of the first adhesive layer 20 and the second adhesive layer 40.

[0095] <Packaging> A packaging according to one embodiment will now be described. Fig. 2 is a schematic plan view of an example of the packaging according to this embodiment. The packaging 200 includes a packaging bag 100 and contents (not shown) accommodated in the packaging bag.

[0096] The packaging bag 100 is formed, for example, by overlapping two sheets of the laminate 1 so that the sealant layers face each other and heat-sealing the four sides.

[0097] The packaging bag 100 is a four-sided bag having a main body 101 in which the contents are accommodated and a sealed portion 102 located at an end of the main body 101. The shape of the main body 101 is not particularly limited and may be, for example, rectangular when viewed from a predetermined direction. At least a portion of the outer surface of the main body 101 may be printed. The main body 101 may contain, for example, a specific gas such as nitrogen in addition to the contents. The sealed portion 102 is a portion where one portion of the sealant layer 50 of the laminate 1 is bonded to another portion. In the sealed portion 102, the one portion of the sealant layer 50 of the laminate 1 is in close contact with the other portion. The sealed portion 102 is formed, for example, by heating and compressing (i.e., heat-sealing) the one portion of the sealant layer 50 of the laminate 1 to the other portion, but is not limited thereto. For example, the sealed portion 102 may be formed by cold sealing or the like.

[0098] The maximum opening heights H1 and H2 of the package 200, measured through the following process, satisfy the following conditions. When the maximum opening heights H1 and H2 satisfy the following conditions, the opening of the package 200 is difficult to close when the opening is positioned vertically downward to discharge the contents, resulting in excellent dischargeability: 4 mm≦H1 6 mm≦H2

[0099] (2a) A step of setting 20 mm from the top end of the packaging bag as the first position and the center of the packaging bag in the height direction as the second position, cutting the packaging bag from one side to the other at the first position, discharging the contents, and then measuring the maximum opening height H1 at the first position with the packaging bag placed on a horizontal table. (2b) After step (2a), a step of cutting the packaging bag from one side to the other at the second position and measuring the maximum opening height H2 at the second position with the packaging bag placed on a horizontal table.

[0100] The first position is shown in Figure 2 by the imaginary line I-I, where the distance L1 from the top end is 20 mm. The second position is shown in Figure 2 by the imaginary line II-II, where the distance from both the top end and the bottom end is the same, 70 mm. Figure 3 is an end view taken along the imaginary line I-I. As shown in Figure 3, the maximum opening height H1 is the maximum distance between the inner edges of the sealant layers. The same is true for the maximum opening height H2. The numerical ranges for the maximum opening heights H1 and H2 may be the same as those for the maximum opening heights H1 and H2 of the laminate 1.

[0101] The seal width S of the packaging bag 100 may be, for example, 2 to 10 mm. The width W1 of the packaging bag 100 may be, for example, 80 to 150 mm. The height W2 of the packaging bag 100 may be, for example, 120 to 200 mm.

[0102] The package 200 may be subjected to a heat treatment at 80° C. or higher, 120° C. or higher, or 135° C. or lower. Examples of the heat treatment include retort treatment and boiling treatment.

[0103] Retort processing is a method of sterilizing microorganisms such as mold, yeast, and bacteria by heating and pressurizing, typically for the preservation of food, pharmaceuticals, etc. Typically, packaging bags containing food, etc. are heated and pressurized at 105-140°C and 0.15-0.30 MPa for 10-120 minutes. Retort devices are available in two types: steam-type, which uses heated steam, and hot water-type, which uses pressurized heated water. The appropriate method is used depending on the sterilization conditions of the food, etc. contained within. Boiling is a moist heat sterilization method for preserving food, pharmaceuticals, etc. Typically, packaging bags containing food, etc. are subjected to moist heat sterilization at 60-100°C and atmospheric pressure for 10-120 minutes, depending on the contents. Boiling is typically performed in a hot water bath at temperatures below 100°C. Methods include a batch method, in which the food is immersed in a hot water bath at a constant temperature for a set period of time and then removed, and a continuous method, in which the food is passed through a tunnel-type hot water bath for processing.

[0104] Examples of the contents include food and medicine. Because the packaging bag 100 has excellent drainability, the contents may contain water, which is generally difficult to drain. The water content may be, for example, 60% by mass or more, preferably 70% by mass or more, and more preferably 75% by mass or more, based on the total amount of the contents. Examples of contents containing water include cooked foods such as soup and pasta sauce, and pet food.

[0105] Although a packaging body according to one embodiment has been described above, the packaging body of the present disclosure is not limited to the above embodiment. For example, the packaging bag may be a standing pouch-shaped packaging bag, a two-sided bag, a three-sided bag, a folded bag, or a gusset bag. The packaging bag may not have a resealable portion or a notch. The packaging bag may have a knot. The notch may be V-shaped, U-shaped, I-shaped, or the like. Furthermore, a group of scars may be formed instead of the notch.

[0106] Examples of the present disclosure will be specifically described below, although the present disclosure is not limited to the following examples.

[0107] <Preparation of Materials> The following materials were prepared as the first base material layer, the second base material layer, the sealant layer, and the adhesive. [First base layer] OPP1A: Biaxially oriented polypropylene film (thickness 20 μm) OPP1B: Biaxially oriented polypropylene film (thickness 20 μm) OPP1C: Biaxially oriented polypropylene film (thickness 20 μm) PET: Polyethylene terephthalate film (thickness 12 μm) [Second base layer] OPP2A: Biaxially oriented polypropylene film (thickness 20 μm) OPP2B: Biaxially oriented polypropylene film (thickness 20 μm) (Sealant layer) CPP-A: Unstretched polypropylene film (thickness 60 μm) CPP-B: Unstretched polypropylene film (thickness 80 μm) CPP-C: Unstretched polypropylene film (thickness 60 μm) CPP-D: Unstretched polypropylene film (thickness 40 μm) CPP-E: Unstretched polypropylene film (thickness 70 μm or 80 μm) (Adhesive) Mitsui Chemicals, Inc., product name: Base agent A525 / Curing agent A52

[0108] [Preparation of Anchor Coating Agent] Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate so that the total solids content (total amount of acrylic polyol and tolylene diisocyanate) was 5 mass%. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare an anchor coating agent.

[0109] [Preparation of Coating Liquid for Barrier Coat Layer] The following liquids A, B, and C were mixed in a mass ratio of 65 / 25 / 10 to prepare a coating liquid for a barrier coat layer. Liquid A: tetraethoxysilane (Si(OC ２ H ５ ) ４ 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of SiO 2 and 10 g of methanol, and the mixture was stirred for 30 minutes to obtain a hydrolyzed solids content of 5% by mass (SiO ２ Solution B: A 5% by mass water / methanol solution of polyvinyl alcohol (mass ratio of water:methanol is 95:5). Solution C: A hydrolysis solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate with a water / isopropyl alcohol mixed solution (mass ratio of water:isopropyl alcohol is 1:1) to a solids content of 5% by mass.

[0110] <Production of Gas Barrier Film (Intermediate Layer)> (Examples 1 to 5, Comparative Examples 1, 2, 5, and 6) The materials shown in Table 1 were used as the second substrate layer. The above anchor coat layer-forming composition was applied to the corona-treated surface of the second substrate layer by gravure roll coating, and then dried and cured at 60°C until the coating amount reached 0.1 g / m. ２ An anchor coat layer made of a polyester polyurethane resin was formed.

[0111] Next, a 30 nm thick transparent inorganic oxide layer (silica vapor deposition layer) made of silicon oxide was formed using an electron beam heating vacuum deposition apparatus. The vapor deposition material type was adjusted to form a vapor deposition layer with an O / Si ratio of 1.8. The O / Si ratio was measured using an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV) with a non-monochromated MgKα (1253.6 eV) X-ray source and an X-ray output of 100 W (10 kV-10 mA). Quantitative analysis to determine the O / Si ratio was performed using relative sensitivity factors of 2.28 for O1s and 0.9 for Si2p, respectively.

[0112] Next, the coating liquid for the barrier coat layer was applied onto the inorganic oxide layer by gravure roll coating, and the coating was dried by heating in an oven under conditions of a tension of 20 N / m and a drying temperature of 120° C. to form an overcoat layer with a thickness of 0.3 μm. This resulted in a gas barrier film having a laminated structure of second substrate layer / anchor coat layer / vapor deposition layer / overcoat layer.

[0113] <Production of Laminate> Laminates of the Examples and Comparative Examples were produced based on the combinations of layers shown in Table 1. The method for producing the laminates is as follows.

[0114] (Examples 1 to 5, Comparative Examples 1, 2, 5, and 6) A first substrate layer was laminated onto the surface of the gas barrier film on the overcoat layer side via an adhesive by dry lamination. A sealant layer was similarly laminated onto the other surface of the second substrate layer of the gas barrier film. This produced a laminate having a layered structure of first substrate layer / adhesive layer / overcoat layer / vapor deposition layer / anchor coat layer / second substrate layer / adhesive layer / sealant layer.

[0115] (Comparative Examples 3 and 4) An AL foil (thickness: 10 μm, MD heat shrinkage: 0%, TD heat shrinkage: 0%) was prepared. A first substrate layer was laminated onto one surface of the AL foil via an adhesive by dry lamination. A sealant layer was similarly laminated onto the surface of the AL foil opposite to the surface on which the first substrate layer was laminated. This produced a laminate having a laminate structure of first substrate layer / adhesive layer / AL foil layer / adhesive layer / sealant layer.

[0116] <Loop Stiffness Value> The laminates of each Example and Comparative Example were retorted by heating at a temperature of 128°C for 15 minutes under a pressure of 0.3 MPa. The loop stiffness value of the heated laminate was measured. A loop stiffness tester manufactured by Toyo Seiki Seisakusho, Ltd. was used for the measurement. A test film having a TD of 15 mm and an MD of 200 mm was prepared from the heated laminate. Both ends of the test film were fixed with chucks to form a loop with a loop size of 85 mm x 15 mm. This loop was compressed with an indenter at a compression speed of 3.3 mm / min, a compression time of 3 seconds, and a compression distance of 20 mm, and the load of the indenter was measured. The maximum load measured in this test was used as the loop stiffness value. The compression distance refers to the distance when the indenter and chuck are closest to each other. The results are shown in Table 2.

[0117] <Measurement of maximum opening heights H1 and H2> The maximum opening heights H1 and H2 were measured through the following steps. The maximum opening height H1 was determined by averaging the values ​​measured for three laminates. Similarly, the maximum opening height H2 was determined by averaging the values ​​measured for three laminates. The results are shown in Table 2.

[0118] (1a) A step of preparing two laminates each having a width of 90 mm and a length of 140 mm as test pieces; (1b) A step of overlapping the two test pieces so that the sealant layers face each other and sealing three sides with a seal width of 5 mm to form a bag; (1c) A step of injecting 70 g of water into the top end of the bag, and then sealing the top end with a seal width of 5 mm to obtain a test piece; (1d) A step of heating the test piece under conditions of a temperature of 128°C, a time of 15 minutes, and a pressure of 0.3 MPa; (1e) After the step (1d), a step of cutting the bag from one side to the other at a first position 20 mm from the top end of the bag, draining the water, and measuring the maximum opening height H1 at the first position while the bag is placed on a horizontal table; (1f) After the step (1e), a step of cutting the bag from one side to the other at a second position 50 mm from the first position, and measuring the maximum opening height H2 at the second position while the bag is placed on a horizontal table.

[0119] In step (1b), an impulse sealer was used. In step (1c), water was poured into the bag, and then the top of the bag was folded to remove the air inside the bag, and the top end was sealed in that state. In step (1d), the test specimen was heated with its main surface positioned horizontally. Heating was performed using a shower method in which water was sprayed onto the test specimen. In step (1e), the water was drained, and the inside of the bag was lightly wiped with a Kimwipe to remove moisture. Furthermore, before measuring the maximum opening height H1, the bag was placed on a horizontal table and the main surface of the bag was pressed with the palm of the hand from the bottom to the top with a force of 2 to 3 kg. In step (1f), before measuring the maximum opening height H2, the bag was placed on a horizontal table and the main surface of the bag was pressed with the palm of the hand from the bottom to the top with a force of 2 to 3 kg.

[0120] <Measurement of Shrinkage Ratio of First Substrate Layer, Second Substrate Layer, Sealant Layer, and Laminate> The heat shrinkage ratios of the first substrate layer, second substrate layer, sealant layer, and laminate of each Example and Comparative Example were measured according to the following procedure. The results are shown in Table 1.

[0121] (1) As shown in FIG. 4, a measurement sample 500 was prepared by cutting a layer or laminate to a size of 200 mm x 200 mm. (2) As shown in FIG. 4, two straight lines L1 and L2, each 120 mm or longer, parallel to the TD of the measurement sample 500 were drawn with a 100 mm gap between them. (3) As shown in FIG. 4, two straight lines L3 and L4, each 120 mm or longer, parallel to the MD of the measurement sample 500 were drawn with a 100 mm gap between them. (4) As shown in FIG. 4, seven scales N1 to N7 were drawn at 20 mm intervals on the line L1. Similar scales were drawn on the lines L2 to L4. The scales on the lines L1 and L2 were aligned so that when each of the scales N1 to N7 on the line L1 was connected to each of the scales N1 to N7 on the line L2, the line would be parallel to the MD. Furthermore, the scales of lines L3 and L4 were aligned so that if a straight line were drawn connecting each of the scales N1 to N7 on line L3 with each of the scales N1 to N7 on line L4, the line would be parallel to the TD. (5) The measurement sample was heated at 128°C for 15 minutes at 0.3 MPa. After heating, the measurement sample was left at room temperature (25°C) for 30 minutes. (6) The linear distance between the scale N1 on line L1 (the intersection of L1 and N1) and the scale N1 on line L2 (the intersection of L2 and N1) was measured as the MD length before and after heating, and the MD heat shrinkage was calculated using the following formula (1). Similarly, the MD heat shrinkage was calculated at each of the scales N1 to N7, and the average value was used as the MD heat shrinkage of the measurement sample 500. MD heat shrinkage (%) = (MD length before heating - MD length after heating) / MD length before heating x 100 (1) (7) The linear distance between the scale N1 of line L3 (intersection of L3 and N1) and the scale N1 of line L4 (intersection of L4 and N1) was measured as the TD length before and after heating, and the TD heat shrinkage was calculated using the following formula (2). Similarly, the TD heat shrinkage was calculated at each of the scales N1 to N7, and the average value was used as the TD heat shrinkage of measurement sample 500. TD heat shrinkage (%) = (TD length before heating - TD length after heating) / TD length before heating x 100 (2)

[0122] <Dischargeability> Two laminates measuring 90 mm wide and 140 mm long were prepared as test pieces. The two test pieces were overlapped with the sealant layers facing each other. Three sides of the test piece were sealed with an impulse sealer (seal width 5 mm) to obtain a packaging bag. Wet pet food (approximately 50 g) was filled into the packaging bag from the top end. The top end of the packaging bag was sealed with an impulse sealer (seal width 5 mm). This yielded a package comprising the packaging bag and the contents (wet pet food).

[0123] The package was heated at a temperature of 128°C for 15 minutes under a pressure of 0.3 MPa. Heating was performed using a shower method in which water was sprayed onto the package. After heating, the package was cut from one side to the other at a first position 20 mm from the top end of the package bag to form an opening. The maximum opening height of the opening was measured. The package was held for 30 seconds with the opening facing downwards in the vertical direction to discharge the contents. After 15 seconds, both sides of the package bag were pinched with both hands and pressed towards the inside of the package bag. The amount of contents discharged in 30 seconds was measured. The discharge rate was calculated using the following formula: Discharge rate (%) = Amount of contents discharged (g) / Filling amount of contents (g) x 100

[0124] The maximum opening height and discharge rate of the opening were evaluated according to the following criteria. The results are shown in Table 2. (Criteria) A: Maximum opening height is more than 25 mm and discharge rate is more than 90% B: Maximum opening height is 20 mm or more and less than 25 mm and discharge rate is more than 90% C: Evaluation other than A and B

[0125] <Handling properties when packaging bag is opened> Two laminates measuring 90 mm wide and 140 mm long were prepared as test pieces. The two test pieces were overlapped with the sealant layers facing each other. Three sides of the test pieces were sealed with an impulse sealer (seal width 5 mm) to obtain a packaging bag. Wet pet food (approximately 50 g) was filled into the packaging bag from the top end. The top end of the packaging bag was sealed with an impulse sealer (seal width 5 mm). This resulted in a package including the packaging bag and the contents (wet pet food). The package was heated at a temperature of 128°C for 15 minutes at a pressure of 0.3 MPa. Heating was performed using a shower method in which water was sprayed onto the package. After heating, the packaging bag was cut from one side to the other at a first position 20 mm from the top end to form an opening. The handling properties of the packaging bag when it was opened were evaluated by grasping the sealed portions on both ends of the package and pushing the sealed portions toward each other, and evaluating the amount of force applied and the ease of maintaining the opening shape according to the following criteria A to D. The evaluation was carried out according to the following criteria. The results are shown in Table 2. (Criteria) A: The opening opens with a light force and is easy to maintain open B: The opening is easy to open and is easy to maintain open C: The packaging bag is hard and the opening is difficult to open, but it is easy to maintain open D: The opening is twisted (twisted) and difficult to open, and it is difficult to maintain open.

[0126]

[0127]

[0128] 1... laminate, 30... intermediate layer, 50... sealant layer, 100... packaging bag, 200... packaging body

Claims

1. A laminate having a laminated structure comprising, in this order, a base layer, an intermediate layer, and a sealant layer, wherein the maximum opening heights H1 and H2 measured through the following steps satisfy the following conditions: 4mm≦H1 6mm≦H2 The maximum opening heights H1 and H2 are: (1a) preparing two of the laminates having a width of 90 mm and a length of 140 mm as test pieces; (1b) overlapping the two test pieces with the sealant layers facing each other and sealing three sides with a seal width of 5 mm to form a bag; (1c) injecting 70 g of water from the upper end of the bag, and then sealing the upper end with a seal width of 5 mm to obtain a test piece; and (1d) heating the test piece under conditions of a temperature of 128°C, a time of 15 minutes, and a pressure of 0.3 MPa. (1e) after step (1d), cutting the bag from one side to the other at a first position 20 mm from the top end of the bag, draining the water, and measuring the maximum opening height H1 at the first position with the bag placed on a horizontal table; and (1f) after step (1e), cutting the bag from one side to the other at a second position 50 mm from the first position, and measuring the maximum opening height H2 at the second position with the bag placed on a horizontal table; and a laminate having a loop stiffness value of 80 mN or more and 220 mN or less after heating at 128°C for 15 minutes.

2. The laminate according to claim 1, wherein when heated at 128°C for 15 minutes, the MD heat shrinkage calculated by the following formula (1) is 1.0% or more and 3.0% or less, and the TD heat shrinkage calculated by the following formula (2) is 1.0% or more and 3.0% or less: MD heat shrinkage (%) = (MD length before heating - MD length after heating) / MD length before heating x 100 ... (1) TD heat shrinkage (%) = (TD length before heating - TD length after heating) / TD length before heating x 100 ... (2) 3. The laminate of claim 1, wherein said sealant layer thermally expands in the MD and thermally shrinks in the TD when heated at 128°C for 15 minutes.

4. The base material layer is heated at 128° C. for 15 minutes, and the MD heat shrinkage rate calculated by the following formula (1) is S1 ＭＤ The thermal shrinkage rate in the TD calculated by the following formula (2) is S1 ＴＤ When this is done, S1 ＭＤ and S1 ＴＤ Difference from (S1 ＭＤ - S1 ＴＤ 2. The laminate according to claim 1, wherein the MD heat shrinkage rate (%) is greater than 0% and less than or equal to 5%. MD heat shrinkage rate (%) = (MD length before heating - MD length after heating) / MD length before heating x 100 ... (1) TD heat shrinkage rate (%) = (TD length before heating - TD length after heating) / TD length before heating x 100 ... (2) 5. The intermediate layer has a second base material layer, and the second base material layer is heated at 128° C. for 15 minutes, and the MD heat shrinkage rate calculated by the following formula (1) is S2 ＭＤ The thermal shrinkage rate of TD calculated by the following formula (2) is S2 ＴＤ When this is done, S2 ＭＤ and S2 ＴＤ Difference with (S2 ＭＤ - S2 ＴＤ 2. The laminate according to claim 1, wherein the MD heat shrinkage rate (%) is greater than 0% and less than or equal to 5%. MD heat shrinkage rate (%) = (MD length before heating - MD length after heating) / MD length before heating x 100 ... (1) TD heat shrinkage rate (%) = (TD length before heating - TD length after heating) / TD length before heating x 100 ... (2) 6. The laminate according to claim 1, wherein the maximum opening heights H1 and H2 satisfy the following conditions: 4 mm≦H1≦7 mm 6 mm≦H2≦9 mm 7. The laminate according to claim 1, wherein the base layer, the intermediate layer and the sealant layer each contain a polypropylene-based resin, and the total mass ratio of the polypropylene-based resin in the laminate is 90 mass% or more.

8. A packaging bag formed using the laminate according to any one of claims 1 to 7.

9. The packaging bag according to claim 8, which is used in applications where heat treatment at 120°C or higher is performed.

10. A packaging bag comprising: a packaging bag; and a content contained in the packaging bag; wherein the packaging bag is formed using a laminate, and the laminate has a laminated structure comprising a base layer, an intermediate layer, and a sealant layer in this order; and wherein the maximum opening heights H1 and H2 measured through the following steps satisfy the following conditions: 4 mm≦H1 6 mm≦H2 The maximum opening heights H1 and H2 are: (2a) a step of cutting the packaging bag from one side to the other at the first position, defining 20 mm from the top end of the packaging bag as a first position and the center of the packaging bag in the height direction as a second position, and after discharging the contents, placing the packaging bag on a horizontal stand and measuring the maximum opening height H1 at the first position; and (2b) after step (2a), a step of cutting the packaging bag from one side to the other at the second position, and placing the packaging bag on a horizontal stand and measuring the maximum opening height H2 at the second position. The package has a loop stiffness value of 80 mN or more and 220 mN or less after heating the laminate at 128°C for 15 minutes.

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