Resin composition, film, laminate, package, and method for producing package

Abstract

To provide a resin composition that enables varied bonded states, such as easy peelability and tight sealability, to manifest more promptly after bonding, influenced by, for example, the temperature used in the bonding process with an intended object, and to provide a film, a laminate, a package, and a method for producing a package.SOLUTION: A resin composition includes component (A): a polypropylene polymer in an amount of 2.5 mass% or more and less than 11.0 mass% relative to the total amount of the composition, component (B): a polymer different from the component (A), and component (C): a nucleating agent in an amount of 0.05 mass% or more and less than 1 mass% relative to the total amount of the composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition, a film, a laminate, a package, and a method for producing the package. [Background technology]

[0002] Conventionally, packaging films have been known that have heat-sealed portions that exhibit different characteristics, with portions that can be peeled off with a relatively weak force (so-called easy-peel portions) and portions that have a relatively strong bonding strength (so-called tight-sealed portions) (see, for example, Patent Documents 1 and 2). The film described in Patent Document 1 is a film made of a resin composition containing: (1) at least one selected from the group consisting of ethylene / α,β-unsaturated carboxylic acid copolymers having a melt flow rate of 0.5 to 6 g / 10 min and ionomers thereof; (2) at least one selected from the group consisting of ethylene / α,β-unsaturated carboxylic acid copolymers having a melt flow rate of 10 to 30 g / 10 min and ionomers thereof; and (3) at least one selected from the group consisting of propylene homopolymers and copolymers of propylene and one or more α-olefins other than propylene. Moreover, the film described in Patent Document 2 is a film made of a resin composition containing at least two kinds of polymers having different solubility parameters and a nucleating agent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2011 / 152324 [Patent Document 2] JP 2018-199744 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for further shortening the time required for the desired sealing properties to be developed in conventional films such as those described in Patent Documents 1 and 2. If it takes a long time for the desired sealing properties to be developed, there is a problem that, for example, the quality control of the product cannot be performed immediately.

[0005] An object of the present invention is to provide a resin composition, a film, a laminate, a package, and a method for producing a package that can quickly exhibit different bonding states, such as easy peel properties and tight seal properties, after bonding, depending on the temperature at which the material is bonded to the object to be bonded. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a resin composition comprising: component (A): a polypropylene polymer in an amount of 2.5 mass% or more and less than 11.0 mass% relative to the total amount of the composition; component (B): a polymer different from component (A); and component (C): a nucleating agent in an amount of 0.05 mass% or more and less than 1 mass% relative to the total amount of the composition.

[0007] In the resin composition according to one aspect of the present invention, the nucleating agent of the component (C) may contain a phosphate metal salt.

[0008] In the resin composition according to one aspect of the present invention, the polypropylene polymer of the component (A) may be a polypropylene random copolymer.

[0009] In the resin composition according to one embodiment of the present invention, the polymer of the component (B) may be at least one of an ethylene-methacrylic acid copolymer and a low-density polyethylene copolymer.

[0010] In the resin composition according to one aspect of the present invention, the solubility parameter of the polypropylene polymer of the component (A) may be different from the solubility parameter of the polymer of the component (B).

[0011] In the resin composition according to one aspect of the present invention, the absolute value of the difference between the solubility parameter of the polypropylene polymer of the component (A) and the solubility parameter of the polymer of the component (B) may be 0.7 or more and 1.2 or less.

[0012] In the resin composition according to one embodiment of the present invention, the component (A) may exhibit an island structure and the component (B) may exhibit a sea structure, and the absolute value of the ratio of the melt flow rate (190°C, under a load of 2160 g) (JIS K7210:1999) of the polypropylene polymer of the component (A) exhibiting the island structure to the melt flow rate (190°C, under a load of 2160 g) (JIS K7210:1999) of the polymer of the component (B) exhibiting the sea structure may be 0.1 or more and 2.6 or less.

[0013] In the resin composition according to one aspect of the present invention, the absolute value of the difference between the melting point of the polypropylene polymer of the component (A) and the melting point of the polymer of the component (B) may be 35 or more and 70 or less.

[0014] According to one aspect of the present invention, there is provided a film made from the resin composition.

[0015] According to one aspect of the present invention, there is provided a laminate comprising a base layer and the film laminated on the base layer.

[0016] According to one aspect of the present invention, there is provided a package formed by overlapping the laminate and heat-sealing a portion of the laminate, the package comprising: a first heat-sealed portion formed by heat-sealing the laminate in a temperature range in a first relationship where the seal strength after heat-sealing saturates with respect to an increase in the heat-sealing temperature; and a second heat-sealed portion formed by heat-sealing the laminate in a temperature range higher than the first relationship in a second relationship that satisfies the following relationship (2) at the heat-sealing temperature where the value of the following relationship (1) is maximized. (Seal strength after heat sealing at heat sealing temperature) - (Seal strength after heat sealing at the heat sealing temperature - 10°C) (1) (Seal strength after heat sealing at heat sealing temperature) - (Seal strength after heat sealing at the heat sealing temperature - 10°C) > 1.3 (2)

[0017] In one embodiment of the packaging body of the present invention, the seal strength after heat sealing in the first heat sealed portion may be 2 N / 25 mm width or more and 15 N / 25 mm width or less in a region where the temperature range is at least 30°C or more, and the seal strength after heat sealing in the second heat sealed portion may be 17 N / 25 mm width or more.

[0018] According to one aspect of the present invention, there is provided a method for producing a package by overlapping the laminate and heat-sealing a portion of the laminate, the method comprising the steps of: heat-sealing the laminate in a temperature range in a first relationship where the seal strength after heat-sealing saturates with respect to an increase in the heat-sealing temperature; and heat-sealing the laminate in a temperature range higher than the first relationship in a second relationship where the heat-sealing temperature is maximized and the heat-sealing temperature satisfies the following relationship (2). (Seal strength after heat sealing at heat sealing temperature) - (Seal strength after heat sealing at the heat sealing temperature - 10°C) (1) (Seal strength after heat sealing at heat sealing temperature) - (Seal strength after heat sealing at the heat sealing temperature - 10°C) > 1.3 (2) Effect of the Invention

[0019] According to one aspect of the present invention, it is possible to provide a resin composition, a film, a laminate, a package, and a method for producing a package, which can quickly exhibit different bonding states, such as easy peel property and tight seal property, after bonding, depending on the temperature at which the material is bonded to the object to be bonded. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic cross-sectional view showing a laminate according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing a package in one embodiment of the present invention. [Diagram 3] 4 is a graph showing the relationship between sealing temperature and sealing strength in Example 1. [Figure 4] 10 is a graph showing the relationship between sealing temperature and sealing strength in Example 2. [Diagram 5] 10 is a graph showing the relationship between sealing temperature and sealing strength in Example 3. [Figure 6] 10 is a graph showing the relationship between sealing temperature and sealing strength in Example 4. [Figure 7] 10 is a graph showing the relationship between sealing temperature and sealing strength in Example 5. [Figure 8] 11 is a graph showing the relationship between sealing temperature and sealing strength in Example 6. [Figure 9] 11 is a graph showing the relationship between sealing temperature and sealing strength in Example 7. [Figure 10] 1 is a graph showing the relationship between sealing temperature and sealing strength in Comparative Example 1. [Figure 11] 13 is a graph showing the relationship between sealing temperature and sealing strength in Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, etc. In this specification and the drawings, components having substantially the same functional configurations are denoted by the same reference numerals, and redundant explanations will be omitted.

[0022] First Embodiment [Resin composition] The resin composition according to this embodiment contains the following components (A), (B), and (C). Component (A): polypropylene polymer, 2.5% by mass or more and less than 11.0% by mass of the total amount of the resin composition Component (B): A polymer different from component (A) Component (C): A nucleating agent in an amount of 0.05% by mass or more and less than 1% by mass based on the total amount of the resin composition Each component will be described below.

[0023] Ingredient (A) The component (A) contained in the resin composition according to the present embodiment is a polypropylene polymer. Examples of the polypropylene polymer include homopolypropylene (HPP), polypropylene random copolymer, and polypropylene block copolymer. From the viewpoint of suitable compatibility with ethylene-methacrylic acid copolymer and polyethylene copolymer, which are preferably used as the component (B), which is another type of polymer described later, and the temperature range for forming a part exhibiting tight sealability in the package (second heat seal part 15 in FIG. 3 described later), a polypropylene random copolymer is suitable as the component (A). Note that homopolypropylene and polypropylene block copolymer have melting points of around 160°C. For this reason, the temperature at which the tight sealability is exhibited in the second heat seal part 15 becomes higher, so a polypropylene random copolymer as the component (A) is effective when it is necessary to handle high temperatures depending on the packaged item and the application.

[0024] The lower limit of the amount of component (A) is 2.5% by mass or more based on the total amount of the resin composition. If the amount of component (A) is less than 2.5% by mass based on the total amount of the resin composition, the proportion of the so-called island structure may decrease, and easy peel properties may not be exhibited. The lower limit of the amount of component (A) is preferably 3.0% by mass or more, more preferably 3.5% by mass or more, and even more preferably 4.0% by mass or more. The upper limit of the amount of component (A) is less than 11.0% by mass. If the amount of component (A) is 11.0% by mass or more based on the total amount of the resin composition, the fusion of both components (A) and (B) may be inhibited during heat sealing in the second temperature range described below, and tight sealing properties may not be exhibited. The upper limit of the amount of component (A) is preferably 10.0% by mass or less, more preferably 9.0% by mass or less, even more preferably 8.0% by mass or less, and even more preferably less than 5.0% by mass.

[0025] ·Component (B) The component (B) contained in the resin composition according to this embodiment is a polymer different from the component (A). Specific examples of the copolymer of component (B) include ethylene-methacrylic acid copolymers and polyethylene copolymers. The polyethylene copolymer may be a low-density polyethylene copolymer, etc. The low-density polyethylene copolymer can form an island-sea structure with the polypropylene copolymer of component (A), which is suitable for achieving easy peelability and tight sealability. The copolymer of component (B) in the resin composition of this embodiment is preferably at least one of an ethylene-methacrylic acid copolymer and a low-density polyethylene copolymer.

[0026] The blending amount of the copolymer of component (B) may be an amount such that the sum of the blending amounts of components (A), (B) and (C) becomes 100% by mass. From the viewpoint of exhibiting tight sealability, the lower limit of the blending amount of the copolymer of component (B) is preferably 88.00 mass% or more relative to the total amount (100 mass%) of components (A) to (C), more preferably 90.40 mass% or more, and even more preferably 91.60 mass% or more. From the viewpoint of expressing easy peel properties, the upper limit of the blending amount of the copolymer of component (B) is preferably 97.45 mass% or less based on the total amount of components (A) to (C), more preferably 96.40 mass% or less, and even more preferably 95.85 mass% or less.

[0027] ·Component (C) Examples of the nucleating agent of component (C) include metal phosphates, metal fatty acid salts, metal carboxylates, metal rosin salts, talc, mica, and sorbitol derivatives. When ethylene-methacrylic acid copolymers and polyethylene copolymers are used as component (B), the nucleating agent of component (C) is preferably one or more of metal phosphates, metal fatty acid salts, and metal carboxylates, and more preferably metal phosphates, from the viewpoint of promoting uniform crystal formation of these copolymers. In particular, metal phosphates are expected to have an effect of suppressing the change over time in tight sealability by increasing the crystallization speed of the polypropylene copolymer of component (A) (bringing closer the seal strength corresponding to each sealing temperature after 24 hours and immediately after).

[0028] The lower limit of the amount of component (C) is 0.05% by mass or more based on the total amount of the resin composition. If the amount of component (C) is less than 0.05% by mass based on the total amount of the resin composition, the nucleation action is insufficient, so the crystallization speed after heat sealing is slow, and it may take time to develop easy peel properties in particular. The lower limit of the amount of component (C) is preferably 0.07% by mass or more based on the total amount of the resin composition, more preferably 0.10% by mass or more, and even more preferably 0.15% by mass or more. The upper limit of the amount of the nucleating agent of component (C) is less than 1 mass% based on the total amount of the resin composition. Even if the amount of component (C) is 1 mass% or more based on the total amount of the resin composition, the nucleating effect is saturated, and there is a risk of costs increasing with an increase in the amount of the nucleating agent added. The upper limit of the amount of the nucleating agent of component (C) is preferably 0.80 mass% or less, more preferably 0.60 mass% or less, and even more preferably 0.40 mass% or less. In this way, the amount of the nucleating agent (component (C)) added can control the change in sealing properties over time. In this specification, the amount of the nucleating agent (component (C)) is the net amount in the master batch.

[0029] To the resin composition according to one embodiment of the present invention, at least one selected from the group consisting of, for example, a lubricant and an antiblocking agent can be added as necessary to improve workability during the formation of a substrate film and during secondary processing such as the manufacture of a package, which will be described later. The resin composition according to one embodiment of the present invention may also contain other components within a range that does not impair the effects of the present invention.

[0030] The resin composition of the present embodiment has a solubility parameter (δ, hereinafter also referred to as the “sp value”) ((cal / cm 3 ) 1 / 2 It is preferable that the solubility parameter of the polymer of component (B) is different from that of the polymer of component (B). For example, when a film made of the resin composition in which one of the two polymers, component (A), has an island structure and the other, component (B), has a sea structure, is heat-sealed in a predetermined temperature range (hereinafter referred to as the "first temperature range"), the component (B) with the island structure in a non-molten state inhibits the fusion of the component (A) with the sea structure in a molten state. As a result, the heat-sealed area exhibits a relatively weak seal strength, i.e., easy peel properties. When the film is heat-sealed in a second temperature range, the fusion of both the molten components (A) and (B) causes the heat-sealed area to exhibit a relatively strong seal strength, i.e., tight seal properties. After heat-sealing, crystallization immediately proceeds due to the nucleating agent, and the seal properties of the heat-sealed area are expressed in a short time. In this way, by blending a polymer with a different sp value and a nucleating agent, for example, sealing properties such as easy peelability and tight sealability can be exhibited immediately after bonding of the film. Furthermore, the first temperature region and the second temperature region can be clearly differentiated from each other based on the relationship between temperature and layer structure, and the easy peelability and tight sealability can be easily exhibited in an article using the resin composition.

[0031] Here, the sea-island structure refers to a phase structure that indicates a mixed state of incompatible resins, in which one resin is dotted like islands in the other incompatible resin. Furthermore, the joining of a film made of the resin composition is not limited to heat sealing, but also includes ultrasonic welding and the like. The sp value (δ) is calculated according to the calculation method proposed by Fedors. Specifically, Ev (energy of vaporization) and V (molar volume) are obtained from the table in "Polym. Eng. Sci., 14(2), 147-154 (1974)" and calculated based on the following formula (S1). δ=(Ev / V) 1 / 2 …(S1) When component (A) is a polypropylene random copolymer, the sp value is 8.0.

[0032] The absolute value of the difference between the sp value of component (A) and the sp value of component (B) is preferably 0.7 or more and 1.2 or less. Here, when the sp value of component (A) is sp(A) and the sp value of component (B) is sp(B), if |sp(A)-sp(B)| is 0.7 or more, the compatibility between component (A) and component (B) is not too high, and a suitable dispersion state for expressing the required sealing properties can be formed. On the other hand, if |sp(A)-sp(B)| is 1.2 or less, the compatibility between component (A) and component (B) is not too low, and a suitable dispersion state for expressing the required sealing properties can be formed, and the film-forming properties of the base film made of the resin composition are stable due to the stability of the dispersion states of both components. For example, when polypropylene and nylon 12 (SP value = 9.9) are used as polymers in the resin composition, the compatibility may be significantly deteriorated and the film-forming properties may become unstable. Therefore, it is preferable to set the absolute value of the difference in the sp values ​​of component (A) and component (B) to 0.7 or more and 1.2 or less. For example, even when polypropylene (SP value = 7.9) is used as component (A) and ethylene-methacrylic acid copolymer (SP value = 9.1) and low-density polyethylene (SP value = 8.6) are used as component (B), easy peelability and tight sealability can be clearly provided.

[0033] The melting point and melt flow rate of each component are appropriately set depending on the intended sealing properties, such as the packaged item and application. For example, when component (A) has an island structure and component (B) has a sea structure, the absolute value of the ratio of the melt flow rate (MFR) of component (A) having an island structure to the melt flow rate of the polymer of component (B) having a sea structure is preferably 0.1 to 2.6. In other words, when the MFRs of components (A) and (B) are MFR(A) and MFR(B), respectively, the relationship between MFR(A) and MFR(B) is preferably 0.1≦|MFR(A)÷MFR(B)|≦2.6. If |MFR(A)÷MFR(B)| is 0.1 or more, the islands in the sea-island structure will not become too large, and a suitable dispersion state for expressing the required sealing properties will be formed. On the other hand, if |MFR(A)÷MFR(B)| is 2.6 or less, the islands in the sea-island structure will not become too small, and a suitable dispersion state for expressing the required sealing properties will be formed. The absolute value of the ratio of the melt flow rate of component (A) to the melt flow rate of component (B) is more preferably 0.3 or more and 2.5 or less, and even more preferably 0.4 or more and 2.4 or less, in order to achieve the desired easy peel property and tight seal property more quickly, while at the same time lowering the sealing temperature at which tight seal strength is developed, thereby enabling processing to be carried out without damaging the package in practice. The melt flow rates of components (A) and (B) in this specification are values ​​measured in accordance with JIS K7210:1999, at 230°C under a load of 2160 g for component (A) and at 190°C under a load of 2160 g for component (B).

[0034] In addition, it is preferable that the absolute value of the difference between the melting point of component (A) and the melting point (Melting Point: MP) of component (B) is 35 or more and 70 or less. In other words, when the melting points of component (A) and component (B) are MP(A) and MP(B), respectively, it is preferable that the relationship between MP(A) and MP(B) is 35≦|MP(A)-MP(B)|≦70. If |MP(A)-MP(B)| is 35 or more, the first temperature range for heat sealing to exhibit easy peel properties is not too narrow, and the sealing temperature is easily controlled, so that the required sealing properties can be stably exhibited. On the other hand, if |MP(A)-MP(B)| is 70 or less, when a film produced from the resin composition is used as a sealant layer and the sealant layer is laminated with a base film to perform heat sealing, the melting point of the polyolefin resin, nylon resin, polyethylene terephthalate resin, etc. used as the base layer and the second temperature range are not too close, so that adhesion to the seal bar during heat sealing and shrinkage and wrinkles in the second heat-sealed part of the package made of the base film can be prevented. The absolute value of the difference between the melting point of component (A) and the melting point of component (B) is more preferably 38 or more and 70 or less, and even more preferably 40 or more and 70 or less. For example, even when polypropylene (melting point 135°C or more and 160°C or less) is used as component (A) and ethylene-methacrylic acid copolymer (melting point 99°C) and ethylene-vinyl acetate copolymer (melting point 89°C) or the like are used as component (B), easy peel property and tight seal property can be clearly provided. The melting point of each component in this specification can be measured, for example, by differential scanning calorimetry (DSC).

[0035] (Method of producing resin composition) The resin composition according to one embodiment of the present invention can be produced by melt-kneading each component by any method.

[0036] [film] Next, a film according to an embodiment of the present invention will be described. The film according to the present embodiment is made of the above-mentioned resin composition as a raw material. By using the above-mentioned resin composition as a raw material, for example, the different sealing properties of easy peel property and tight seal property can be expressed immediately after heat sealing as a part to be heat sealed. Furthermore, since the first temperature region and the second temperature region can be clearly differentiated, the different sealing properties of easy peel property and tight seal property can be easily set.

[0037] (Film manufacturing method) The film according to one embodiment of the present invention can be produced by an inflation method, or by various other methods such as a calendar method, etc. Furthermore, the method is not limited to co-extrusion, and may be, for example, lamination of a film corresponding to a sealant layer and a film corresponding to a base layer. The substrate film is not limited to a laminated structure in which a substrate layer and a sealant layer are laminated, and may be a single-layer film formed from the resin composition according to one embodiment of the present invention.

[0038] [Laminate] Next, a laminate according to an embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view of a laminate 30 according to this embodiment. The laminate according to one embodiment of the present invention includes a base layer 20 and a film 10 laminated on the base layer 20. The film 10 can be a film according to one embodiment of the present invention.

[0039] The base layer 20 is made of, for example, a polyolefin resin, a nylon resin, a polyethylene terephthalate resin, or the like. Examples of polyolefin resins that can be used include polypropylene resins such as homopolypropylene (HPP), random polypropylene (RPP), and block polypropylene (BPP); polyethylene resins such as high-density polyethylene (HDPE) and (linear) low-density polyethylene (LDPE); and linear ethylene-α-olefin copolymers. As the nylon resin, nylon 6, nylon 8, nylon 11, nylon 12, nylon 6,6, nylon 6,10, nylon 6,12, etc. can be used. In addition, various additives such as colorants can be appropriately added to the base layer.

[0040] In this way, the laminate according to one embodiment of the present invention is laminated with a film that can be easily set to have different properties, i.e., easy peel property and tight seal property, and can exhibit the different properties immediately after heat sealing. As a result, the required sealing property can be stably exhibited immediately after heat sealing, making it easy to control the quality of the heat-sealed portion, and the laminate can be suitably applied to various packages such as packaging bags, thereby improving versatility.

[0041] (Method of manufacturing laminate) The laminate can be produced by various methods, such as an inflation method.

[0042] [Packaging] In this embodiment, the package is exemplified as a bag-shaped package having two storage spaces, but various configurations, such as a package consisting of a container and a lid, can be used, and the number of storage spaces is not limited to two, and may be multiple. The packaged items can be various items other than food, such as medicines, medical supplies, stationery, and miscellaneous goods. Heat sealing is exemplified as the joining method for forming the package from the laminate, but ultrasonic welding, for example, can be used.

[0043] A package according to one embodiment of the present invention is a package formed by overlapping the laminate according to one embodiment of the present invention and heat-sealing a portion thereof, the package comprising: a first heat-sealed portion formed by heat-sealing the laminate in a temperature range in a first relationship where the seal strength after heat-sealing saturates with respect to an increase in the heat-sealing temperature; and a second heat-sealed portion formed by heat-sealing the laminate in a temperature range higher than the first relationship in a second relationship that satisfies the following relationship (2) at the heat-sealing temperature where the value of the following relationship (1) is maximized. (Seal strength after heat sealing at heat sealing temperature) - (Seal strength after heat sealing at the heat sealing temperature - 10°C) (1) (Seal strength after heat sealing at heat sealing temperature) - (Seal strength after heat sealing at the heat sealing temperature - 10°C) > 1.3 (2)

[0044] In this embodiment, when the laminates are stacked and heat-sealed by heating, the first heat-sealed portion formed by heat-sealing in a temperature range (first temperature region) that is the first relationship exhibits easy peel properties. The second heat-sealed portion formed by heat-sealing in a temperature range (second temperature region) that is higher than the first relationship exhibits tight seal properties. These different sealing properties make it easy to cook, for example, by storing different ingredients in one package, peeling off the first heat-sealed portion to mix the different ingredients, and then peeling off the second heat-sealed portion to take out the mixed food. Furthermore, in the second relationship, if the maximum value of the ratio of the seal strength after heat sealing to the heat sealing temperature is greater than 1.3 N / 25 mm / °C, the difference between the ratio of the seal strength after heat sealing to the heat sealing temperature in the first relationship will not become too small, making it easy to judge the condition after heat sealing. Here, the packaging body is not limited to a bag, and various forms of containers, such as a container body and a lid that are heat sealed, can be used. Also, the bag configuration can be a gusset type with folds on the sides and bottom. The term "saturation of the seal strength after heat sealing with respect to the increase in the heat sealing temperature" refers to a substantially constant state in which the seal strength after heat sealing does not change much even if the heat sealing temperature is increased. In this state, some variation in the seal strength is included as long as it is clearly differentiated from the rate of change in the seal strength in other temperature ranges. The seal strength in this specification can be measured in accordance with the method for measuring seal strength described in the Examples below. The second temperature region is a temperature region higher than the first temperature region, and is also a temperature region in which both component (A) and component (B) are in a molten state.

[0045] In this embodiment, the seal strength after heat sealing in the first heat seal portion can be configured to be 2 N / 25 mm width or more and 15 N / 25 mm width or less in a region where the temperature range is at least 30°C or more, and the seal strength after heat sealing in the second heat seal portion can be configured to be 25 N / 25 mm width or more. By making the first heat-sealed portion have a predetermined seal strength and the second heat-sealed portion have a predetermined seal strength or more, the functions of the first heat-sealed portion and the second heat-sealed portion in the package can be properly exerted. More specifically, if the seal strength of the first heat-sealed portion is 2 N / 25 mm width or more, no external force will act on the packaging bag containing the contents during transportation, etc., and the first heat-sealed portion will not peel off unintentionally. On the other hand, if the seal strength of the first heat-sealed portion is 15 N / 25 mm width or less, the difference in seal strength with the second heat-sealed portion will not become too small, and the first heat-sealed portion can be selectively peeled off. In addition, when the desired seal strength is achieved in the first heat-sealed portion within a temperature range of 30° C. or more, even if the heat-sealing conditions for forming a packaging bag vary, the first heat-sealed portion can have the desired seal strength and unintended peeling of the first heat-sealed portion can be prevented. Furthermore, the difference in seal strength between the first heat-sealed portion and the second heat-sealed portion does not become too small, and the first heat-sealed portion can be selectively peeled off. Furthermore, if the seal strength of the second heat-sealed portion is 17 N / 25 mm width or more, peeling of the second heat-sealed portion can be prevented even when the internal pressure of the package containing the contents is increased by, for example, cooking and sterilizing the package, etc. For this reason, it is preferable that the seal strength of the second heat-sealed portion is 17 N / 25 mm width or more.

[0046] (Package Composition) As shown in Fig. 2, the packaging body 1 is formed, for example, by a three-sided bag making method, and has a bag shape in which a base film 11, which is a laminate, is overlapped and its periphery is heat-sealed. The packaging body 1 has a first heat-sealed portion 14 that divides a first storage space 12 and a second storage space 13 inside, and a second heat-sealed portion 15 in which the periphery of the base film 11 is heat-sealed. The above-mentioned laminate may be used as the base film 11. Note that the base film 11 is not limited to a two-layer structure, and may have a multi-layer structure in which various other intermediate layers and laminate layers are appropriately laminated. The first storage space 12 stores, for example, seasoning liquid, and the second storage space 13 stores, for example, food ingredients. The first heat-sealed portion 14 exhibits so-called easy-peel properties, which means that it can be peeled off with a relatively weak force such as internal pressure, and peeling of the first heat-sealed portion 14 connects the first storage space 12 and the second storage space 13, allowing the seasoning liquid and ingredients to mix. The second heat-sealed portion 15 exhibits so-called tight seal properties, which means that it does not peel off with, for example, internal pressure, and has a relatively strong seal strength. The packaging body 1 is provided with a first inlet 16 into which seasoning liquid can be poured and which is sealed by forming a second heat-sealed portion 15 after the seasoning liquid is poured, and a second inlet 17 into which food ingredients can be poured and which is sealed by forming a second heat-sealed portion 15 after the food ingredients are poured.

[0047] [Manufacturing method of packaging body] Next, a method for producing the packaging bag will be described. A method for producing a package according to one embodiment of the present invention is a method for producing a package by overlapping the above-mentioned laminates and heat-sealing a portion of them, which includes the steps of: heat-sealing the laminate in a temperature range in a first relationship where the seal strength after heat-sealing saturates with respect to an increase in the heat-sealing temperature; and heat-sealing the laminate in a temperature range higher than the first relationship in a second relationship where the heat-sealing temperature is maximized and the heat-sealing temperature satisfies the following relationship (2). (Seal strength after heat sealing at heat sealing temperature) - (Seal strength after heat sealing at the heat sealing temperature - 10°C) (1) (Seal strength after heat sealing at heat sealing temperature) - (Seal strength after heat sealing at the heat sealing temperature - 10°C) > 1.3 (2)

[0048] The manufacturing method of the packaging body 1 is, for example, using a manufacturing device for three-sided bag making, and includes a film feeding process in which the base film 11 is fed and overlapped, a first heat sealing process in which the overlapping base film 11 is heat sealed to form a first heat sealed portion 14, and a second heat sealing process in which the overlapping base film 11 is heat sealed to form a second heat sealed portion 15. In the film delivery step, the base film 11 wound around a take-up roll is pulled out, and the sealant layers are overlapped so as to face each other, and the base film 11 is delivered.

[0049] In the first heat sealing step, the overlapping base film 11 is heat sealed with a seal bar set in a first temperature range to form a first heat sealed part 14 exhibiting easy peelability. In the first temperature range in this first heat sealing step, the component (A) constituting the sealant layer exhibits a layer structure in which the component (B) has a so-called island structure and the component (A) has a so-called sea structure. In this first temperature range, the crystallized component (A) becomes a state that inhibits fusion by the molten component (B), and the seal strength is relatively weak, resulting in easy peel properties. In this first temperature range, the seal strength does not fluctuate much, and becomes a constant state in which the seal strength is saturated with respect to temperature.

[0050] Here, the seal strength of the first heat-sealed portion 14 preferably exhibits a certain degree of easy peelability in a temperature range of at least 30° C. The seal strength is preferably set to 2N / 25 mm width or more and 15N / 25 mm width or less, more preferably 2N / 25 mm width or more and 13N / 25 mm width or less, and even more preferably 2N / 25 mm width or more and 10N / 25 mm width or less. That is, the blending of the resin composition of the sealant layer is set so that the seal strength of the first heat-sealed portion 14 is 2N / 25 mm width or more and 15N / 25 mm width or less. Specifically, the seal strength is adjusted by increasing or decreasing the blending amounts of the components (A) and (B), respectively.

[0051] In the second heat sealing step, the overlapping base film 11 is heat sealed with a seal bar set in a second temperature range to form a tight-sealing second heat-sealed part 15. In the second temperature range in this second heat sealing step, the component (A) and the component (B) constituting the sealant layer are in a molten state, forming a layer structure. In this second temperature range, the fusion of both molten components (A) and (B) results in tight sealability with relatively strong heat strength. In this second temperature range, the relationship in which the maximum value of the ratio of the seal strength to the heat seal temperature is 1.3 N / 25 mm / °C or more is defined as the second relationship. In this manner, the sealant layer heat-seals the base film 11 in a second temperature range having a second relationship in which both components (A) and (B) melt, thereby forming a second heat-sealed portion 15 with tight sealing properties.

[0052] Here, the seal strength of the second heat sealed portion 15 is preferably 17 N / 25 mm width or more, more preferably 30 N / 25 mm width or more, and further preferably 35 N / 25 mm width or more.

[0053] After the first heat sealing step and the second heat sealing step, the package 1 having the first heat sealed portion 14 and the second heat sealed portion 15 formed therein is cut appropriately. Then, a predetermined amount of the packaged item is added to the obtained package 1 through the first insertion opening 16 and the second insertion opening 17 by a filling device not shown, and a second heat seal portion 15 is formed at the first insertion opening 16 and the second insertion opening 17 to seal them, and the packaged item is filled.

[0054] [Effects of the embodiment] In this embodiment, in a resin composition containing two types of polymers (one of which is a polyolefin polymer) and a nucleating agent, the polyolefin polymer and the nucleating agent are set to predetermined blending amounts, so that when a film made from the resin composition is heat-sealed, the desired sealing properties can be stably obtained immediately after heat sealing. If the time until the desired sealing properties are exhibited can be shortened, for example, the quality control of the product can be performed immediately.

[0055] [Variations] Although the best configuration for carrying out the present invention has been disclosed in the above description, the present invention is not limited thereto. That is, the present invention has been mainly described with reference to specific embodiments, but those skilled in the art can make various modifications to the above-described embodiments in terms of materials, quantities, and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention. Therefore, the descriptions limiting the materials, layer structures, etc. disclosed above are illustrative to facilitate understanding of the present invention and do not limit the present invention. Descriptions using names that remove some or all of the limitations on the materials, etc. are included in the present invention.

[0056] For example, the method of manufacturing the package 1 is not limited to three-sided bag making, and various methods can be used, such as a rotating drum method, a pillow method, etc. Also, the package may be configured with a fastening member such as a zipper tape so that it can be resealed after the packaged item is inserted or removed. In addition, the base film 11 can be produced by various methods such as an inflation method, a calendar method, etc. Furthermore, the method is not limited to co-extrusion, and may be, for example, lamination of a film corresponding to the sealant layer and a film corresponding to the base layer.

[0057] The base film 11 is not limited to a laminated structure in which a base layer and a sealant layer are laminated, and may be a single-layer film formed from the resin composition of the present invention. Furthermore, the composition of the raw materials of the resin composition, the blending amounts, the sp values ​​of the components (A) and (B), the melt flow rate, the melting point, and the like are not limited to those in the above embodiment and may be set appropriately. EXAMPLES

[0058] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The film configuration, raw materials, preparation of test pieces, and measurement of heat-sealing bonding strength in each example were carried out in the following manner.

[0059] [Examples 1 to 7, Comparative Examples 1 to 2] Using the following raw materials, a three-layer film having a sealant layer with a thickness of 7.5 μm, an intermediate layer with a thickness of 25 μm, and a laminate layer with a thickness of 17.5 μm was produced by inflation molding. For the sealant layer and the intermediate layer, resin compositions were prepared in advance by blending the raw materials, and the resin compositions were used for the inflation molding.

[0060] <Raw materials> (Sealant layer) Component (A): Propylene-ethylene copolymer (sp value: 7.9, MFR (230°C, under 2160g load): 3.0g / 10min, density: 0.900g / cm 3 , melting point: 142℃) Component (B): Ethylene-methacrylic acid copolymer (sp value: 9.1, MFR (190°C, under 2160g load): 3.0g / 10min, density: 0.930g / cm 3Melting point: 99℃ ) Component (C-1): Organophosphate metal salt-based nucleating agent (a masterbatch containing the same component is manufactured by ADEKA Corporation under the trade name M-801 (polypropylene containing 5% by mass of phosphate aluminum salt)) Component (C-2): fatty acid metal salt-based nucleating agent (a masterbatch containing the same component is manufactured by Riken Vitamin Co., Ltd. under the trade name Rikemaster CN-002 (a high-density polyethylene containing approximately 2% by mass of zinc stearate))

[0061] (Middle class) Linear low-density polyethylene (MFR (190°C, 2160g load) (JIS K7210:1999): 1.9g / 10min, density: 0.920g / cm 3 ) 62% by mass Low density polyethylene (MFR (190°C, 2160g load) (JIS K7210:1999): 2.0g / 10min, density 0.922g / cm 3 ) 38% by mass

[0062] (Laminate layer) Linear low-density polyethylene (MFR (190°C, 2160g load) (JIS K7210:1999): 1.9g / 10min, density: 0.920g / cm 3 ) 100.00% by mass

[0063] <Preparation of test pieces for measuring bonding strength> According to the formulations shown in Tables 1 and 2 below, a three-layer film was produced by inflation molding. The sealant layers of the obtained films were heat-sealed at various temperatures using a thermal gradient tester (manufactured by Toyo Seiki Seisakusho, Ltd., product name: HG-100-2) to prepare test pieces.

[0064] [Table 1]

[0065] [Table 2]

[0066] <Seal strength> Using a tensile tester (product name: AGS-X) manufactured by Shimadzu Corporation, the seal strength of the test pieces of each example was measured immediately after heat sealing and after leaving them to stand for 24 hours after heat sealing in accordance with the T-peel test method of JIS K6854-3:1999. The seal strength was measured by T-peeling the test pieces of each example at a tensile speed of 200 mm / min in MD and TD. The results of Example 1 are shown in Table 3 and FIG. 3, the results of Example 2 are shown in Table 4 and FIG. 4, the results of Example 3 are shown in Table 5 and FIG. 5, the results of Example 4 are shown in Table 6 and FIG. 6, the results of Example 5 are shown in Table 7 and FIG. 7, the results of Example 6 are shown in Table 8 and FIG. 8, the results of Example 7 are shown in Table 9 and FIG. 9, the results of Comparative Example 1 are shown in Table 10 and FIG. 10, and the results of Comparative Example 2 are shown in Table 11 and FIG. 11.

[0067] [Table 3]

[0068] [Table 4]

[0069] [Table 5]

[0070] [Table 6]

[0071] [Table 7]

[0072] [Table 8]

[0073] [Table 9]

[0074] [Table 10]

[0075] [Table 11]

[0076] <Evaluation Results> As is clear from the measurement results shown in Tables 3 to 11 and Figures 3 to 11, in Examples 1 to 7, the difference in the graph shape between the first relationship and the second relationship was smaller for the seal strength immediately after heat sealing and the seal strength after leaving it still for 24 hours after heat sealing, and it was confirmed that the change in seal strength over time was small and the seal characteristics could be developed after heat sealing, compared to Comparative Example 1. Also, in Examples 1 to 7, the seal strength after leaving it still for 24 hours after heat sealing showed tight sealability (second relationship) up to a sealing temperature of 230°C, compared to Comparative Example 2, and the effect on the surface substrate during heat sealing can be reduced in practice. Furthermore, as can be seen from a comparison between the results of Example 4 and the results of Example 7, it was shown that the use of a metal salt of phosphate as component (C) in particular provided an excellent effect in inhibiting deterioration of the tight sealability over time. [Explanation of symbols]

[0077] 1...packaging body, 11...base film (film, laminate), 14...first heat-sealed portion, 15...second heat-sealed portion.

Claims

1. A resin composition comprising: Component (A): a polypropylene polymer in an amount of 2.5% by mass or more and less than 11.0% by mass based on the total amount of the composition; Component (B): a polymer different from Component (A); Component (C): a nucleating agent in an amount of 0.05% by mass or more and less than 1% by mass based on the total amount of the composition; The resin composition containing these.

2. In the resin composition according to Claim 1, The nucleating agent of Component (C) contains a metal phosphate ester salt. The resin composition.

3. In the resin composition according to Claim 1, The polypropylene polymer of Component (A) is a polypropylene random copolymer. The resin composition.

4. In the resin composition according to Claim 1, The polymer of Component (B) is at least one of an ethylene-methacrylic acid copolymer and a low-density polyethylene copolymer. The resin composition.

5. In the resin composition according to Claim 1, The solubility parameter of the polypropylene polymer of Component (A) is different from the solubility parameter of the polymer of Component (B). The resin composition.

6. In the resin composition according to Claim 1, The absolute value of the difference between the solubility parameter of the polypropylene polymer of Component (A) and the solubility parameter of the polymer of Component (B) is 0.7 or more and 1.2 or less. The resin composition.

7. In the resin composition according to Claim 1, Component (A) shows an island structure and Component (B) shows a sea structure. The absolute value of the ratio of the melt flow rate (at 190 °C, under a load of 2160 g) (JIS K7210:1999) of the polymer of the component (B) showing the sea structure to the melt flow rate (at 230 °C, under a load of 2160 g) (JIS K7210:1999) of the polypropylene polymer of the component (A) showing the island structure is 0.1 or more and 2.6 or less, resin composition.

8. In the resin composition according to claim 1, The absolute value of the difference between the melting point of the polypropylene polymer of the component (A) and the melting point of the polymer of the component (B) is 35 or more and 70 or less, resin composition.

9. A film made from the resin composition according to any one of claims 1 to 8, film.

10. A base material layer, The film according to claim 9 laminated on the base material layer, A laminate comprising:

11. A package formed by laminating the laminate according to claim 10 and partially heat-sealing it, In the first relationship where the seal strength after heat-sealing saturates with an increase in the heat-sealing temperature, a first heat-sealed portion formed by heat-sealing the laminate in the temperature range, In a second relationship that satisfies the following relational expression (2) at a heat-sealing temperature at which the value of the following relational expression (1) is maximized in a temperature range higher than the first relationship, a second heat-sealed portion formed by heat-sealing the laminate in the temperature range, A package comprising: (Seal strength after heat-sealing at the heat-sealing temperature) - (Seal strength after heat-sealing at a temperature 10 °C lower than the heat-sealing temperature) ... (1) (Seal strength after heat sealing at the heat-sealing temperature) - (Seal strength after heat sealing at a temperature 10°C lower than the heat-sealing temperature) > 1.3... (2)

12. In the package according to claim 11, the seal strength after heat sealing in the first heat-sealing portion is 2 N / 25 mm width or more and 15 N / 25 mm width or less in a region having a temperature range of at least 30°C or more, and the seal strength after heat sealing in the second heat-sealing portion is 17 N / 25 mm width or more. Package.

13. A manufacturing method for manufacturing a package by overlapping the laminates according to claim 10 and heat-sealing a part thereof, in a first relationship in which the seal strength after heat sealing saturates with an increase in the heat-sealing temperature, a step of heat-sealing the laminate in the temperature range; in a temperature range higher than the first relationship, in a second relationship satisfying the following relational expression (2) at a heat-sealing temperature at which the value of the following relational expression (1) is maximized, a step of heat-sealing the laminate in the temperature range; A method for manufacturing a package, which performs the above steps. (Seal strength after heat sealing at the heat-sealing temperature) - (Seal strength after heat sealing at a temperature 10°C lower than the heat-sealing temperature)... (1) (Seal strength after heat sealing at the heat-sealing temperature) - (Seal strength after heat sealing at a temperature 10°C lower than the heat-sealing temperature) > 1.3... (2)

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