JP2018199744A - Resin composition, film, laminate, package, and manufacturing method of package - Google Patents

Abstract

To provide a resin composition capable of expressing different bonding states just after bonding at a temperature for binding articles to be bonded for example.SOLUTION: There is provided a resin composition by blending at least 2 kinds of polymers having different solubility parameter (sp value) ((cal/cm)), and a nucleating agent.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a resin composition, a film, a laminate, a package, and a method for producing the package.

Conventionally, as a packaging film, the location sealed by heat sealing is different from the location that becomes a so-called easy peel that can be peeled even with a relatively weak force, and the location that becomes a so-called tight seal with a relatively strong bonding strength. A configuration showing characteristics is known (see, for example, Patent Document 1).
The film described in Patent Document 1 is selected from the group consisting of (1) an ethylene / α, β-unsaturated carboxylic acid copolymer having a melt flow rate of 0.5 to 6 g / 10 min, and an ionomer thereof. (2) at least one selected from the group consisting of (2) an ethylene / α, β-unsaturated carboxylic acid copolymer having an melt flow rate of 10 to 30 g / 10 min, and an ionomer thereof; ) A film comprising a resin composition containing a homopolymer of propylene and at least one selected from the group consisting of a copolymer of propylene and one or more α-olefins excluding propylene.

International Publication No. 2011/152324

In the conventional film as described in Patent Document 1, it is desired to further shorten the time until the required sealing characteristics are exhibited. If it takes time to develop the required sealing characteristics, there is a problem that, for example, quality control of a product cannot be immediately performed.
An object of the present invention is to provide a resin composition, a film, a laminate, a package, and a method for producing the package, in which different bonding states can be manifested immediately after bonding depending on, for example, the temperature at which the object is bonded. .

The resin composition of one embodiment of the present invention includes at least two polymers having different solubility parameters (δ, hereinafter referred to as sp value) ((cal / cm ³ ) ^1/2 ), a nucleating agent, , Are blended.

In the present invention, at least two types of polymers having different sp values are incompatible with each other, and therefore incompatible resins of other polymers are scattered like islands in any one type of polymer resin. It has a sea-island structure.
For example, when heat-sealing a film made of the resin composition in which one component (A) of two kinds of polymers has a sea structure and the other component (B) has an island structure, a predetermined temperature range (hereinafter, In the case of heat sealing in the first temperature region), the non-melted island structure component (B) inhibits the fusion of the molten sea structure component (A). As a result, the heat-sealed portion exhibits a so-called easy peel property in which the seal strength is relatively weak. When heat-sealing in the second temperature range (a temperature range higher than the first temperature range, in which both the component (A) and the component (B) are in a molten state), the melted component (A) and Due to the fusion of both components (B), the heat-sealed portion exhibits a so-called tight sealing property with relatively high sealing strength. After heat sealing, crystallization proceeds immediately by the nucleating agent, and the sealing properties of the heat-sealed portion are expressed in a short time.
As described above, in the present invention, by blending a polymer having a different sp value and a nucleating agent, it is possible to express easy peel properties and tight seal properties immediately after joining the films, for example. Furthermore, the first temperature region and the second temperature region can be clearly differentiated from the relationship between temperature and layer structure, and easy peel and tight seal properties in articles using the resin composition can be easily formed. it can.

Here, the sea-island structure is a phase structure showing a mixed state of incompatible resins, and is a state in which the other incompatible resin is scattered like islands in one resin.
Further, for example, the bonding of the film made of the resin composition is not limited to heat sealing, but includes welding by ultrasonic waves.
The sp value (δ) is calculated according to the calculation method proposed by Fedors. Specifically, Ev (evaporation energy) and V (molar volume) in the table described in “Polym.Eng.Sci., 14 (2), 147-154 (1974)” were obtained, and It calculates based on Formula (1).
δ = (Ev / V) ^1/2 (1)

And in this invention, it can also be set as the structure whose absolute value of the difference of sp value of the said at least 2 type polymer is 0.7 or more and 1.2 or less, respectively.
In the present invention, by setting the absolute value of the difference between the sp values of the polymers to a predetermined value, it is possible to form an appropriate dispersion state in expressing the required sealing characteristics.
Here, if the absolute value of the difference in sp value is smaller than 0.7, the compatibility of each polymer is increased, and there is a possibility that a dispersed state for expressing the required sealing properties cannot be formed. On the other hand, when the absolute value of the difference in sp value is larger than 1.2, the dispersion state of each polymer becomes unstable, for example, the film-forming property of the film made of the resin composition becomes unstable. The moldability of the resin composition may become unstable. Therefore, the absolute value of the difference in sp value is preferably set to 0.7 or more and 1.2 or less.

In the present invention, the melt flow rate of the at least two polymers (230 ° C., under a load of 2160 g) (JIS K7210) is a polymer showing an island structure with respect to the melt flow rate of the polymer showing a sea structure. The ratio of the melt flow rate may be 0.1 or more and 1.2 or less, respectively.
In this invention, by setting the ratio of the melt flow rate (hereinafter referred to as MFR) of the polymer to a predetermined value, it is possible to form an appropriate dispersion state in expressing the required sealing characteristics.
Here, when the ratio of MFR becomes larger than 1.2, the island portion of the sea-island structure becomes small, and there is a possibility that the required sealing characteristics cannot be expressed. On the other hand, when the MFR ratio is smaller than 0.1, the island portion of the sea-island structure becomes large, and when the large island portion is stretched, the difference in seal characteristics obtained depending on the measurement direction may increase. There is. Therefore, it is preferable to set the ratio of MFR to 0.1 or more and 1.2 or less.

Furthermore, in this invention, it can also be set as the structure whose absolute value of the difference of melting | fusing point of said at least 2 sort (s) of polymer is 35-70 respectively.
In this invention, by setting the absolute value of the difference between the melting points of the polymers to a predetermined value, for example, heat sealing can be easily performed due to the temperature relationship between the first temperature region and the melting point.
Here, if the absolute value of the difference between the melting points is smaller than 35, the first temperature region is narrowed, and for example, the control of the heat seal temperature for stably expressing the required sealing characteristics may be complicated. On the other hand, when the absolute value of the difference in melting points is higher than 70, for example, when a film made of the resin composition is used as a sealant layer, and a laminate in which this sealant layer is laminated with a base material layer is heat sealed, The melting point of the polyolefin resin, nylon resin, polyethylene terephthalate resin, and the like are close to the second temperature region. For this reason, when heat-sealing in the 2nd temperature range, there exists a possibility that the appearance defect of adhering to a seal bar or generating a wrinkle by the shrinkage | contraction of the package body which consists of a laminated body may arise. For this reason, the absolute value of the difference in melting points is preferably 35 or more and 70 or less, more preferably 40 or more and 70 or less.

In the present invention, one of the at least two polymers is a polyolefin polymer, and the blending amount of the polyolefin polymer is 5% by mass or more and 20% by mass or less based on the total amount of the composition. In addition, the blending amount of the nucleating agent may be 1% by mass or more and 3% by mass or less based on the total amount of the composition.
In the present invention, by setting the polyolefin polymer and the nucleating agent among the polymers to a predetermined blending amount, for example, when heat-sealing a film produced from the resin composition, it is obtained immediately after heat sealing. Seal characteristics can be obtained stably.
Here, when the blending amount of the polyolefin polymer is less than 5% by mass with respect to the total amount of the composition, when heat-sealing in the first temperature region, there are few polyolefin polymers that inhibit fusion between other polymers. , Easy peel properties may not be exhibited. On the other hand, when the blending amount of the polyolefin polymer is more than 20% by mass with respect to the total amount of the composition, the fusion of each polymer is inhibited during heat sealing in the second temperature range, and the tight sealing property may not be exhibited. There is. In addition, when the blending amount of the nucleating agent is less than 1% by mass with respect to the total amount of the composition, the nucleating action is insufficient, and the crystallization speed after heat sealing is slowed down. May take time. On the other hand, when the blending amount of the nucleating agent is more than 3% by mass with respect to the total amount of the composition, the nucleating action becomes saturated, and therefore the cost may increase with an increase in the blending amount of the nucleating agent. . Therefore, the blending amount of the polyolefin polymer is preferably 5% by mass or more and 20% by mass or less with respect to the total amount of the composition, and the blending amount of the nucleating agent is preferably 1% by mass or more and 3% by mass or less with respect to the total amount of the composition. .

The film of one embodiment of the present invention is characterized in that the resin composition of the present invention is used as a raw material.
By using the resin composition of the present invention as a raw material, for example, as a portion to be heat-sealed, it is possible to develop a sealing property different from easy peel property and tight seal property immediately after heat sealing. Furthermore, since the first temperature region and the second temperature region can be clearly differentiated, it is possible to easily set different sealing characteristics between the easy peel property and the tight seal property.

The laminate of one embodiment of the present invention includes a base material layer and the film of the present invention stacked on the base material layer.
In this invention, the film which can be easily set to the different characteristic of the easy peel property and tight seal property in this invention, and can express a different characteristic immediately after heat sealing is laminated | stacked. From this, since the required sealing characteristics can be stably expressed immediately after heat sealing, the quality control of the heat sealing portion becomes easy, it can be applied well to various packagings such as packaging bags, and versatility can be improved.

  The package of one embodiment of the present invention is a package in which the laminate of the present invention is overlapped and partly heat-sealed, and has a sealing strength after heat-sealing with respect to an increase in the heat-sealing temperature. In the first relationship that saturates, the first heat-sealed part formed by heat-sealing the laminate in the temperature range, and after heat-sealing to the heat-sealing temperature in the temperature range higher than the first relationship A second heat seal portion formed by heat-sealing the laminate in the temperature range in a second relationship in which the maximum value of the seal strength ratio is 1.3 N / 25 mm / ° C. or more. It is characterized by that.

In the present invention, when the laminate of the present invention is overlaid and heat-sealed by heating, the first heat-sealed portion formed by heat-sealing in the temperature range (first temperature region) that is the first relationship is an easy peel. Showing gender. Moreover, the second heat seal part formed by heat sealing in the temperature range (second temperature region) of the second relationship, which is higher than the first relationship, exhibits tight sealing properties. By having these different sealing characteristics, for example, different foods are stored in one package, and after the first heat seal part is peeled and different foods are mixed, the second heat seal part is peeled and mixed. Cooking can be easily done.
In the second relationship, when the maximum value of the seal strength after heat sealing with respect to the heat sealing temperature is smaller than 1.3 N / 25 mm / ° C., the seal strength after heat sealing with respect to the heat sealing temperature in the first relationship. This is because the difference from the ratio is small and the determination after heat sealing may be difficult.
Here, the packaging body is not limited to a bag, and various forms such as a container in which a container body and a lid are heat sealed can be targeted. Further, the bag structure can also be a gusset type in which a fold is provided on the side or bottom.
And the fact that the seal strength after heat sealing is saturated with respect to the rise in the temperature for heat sealing means that the seal strength after heat sealing does not change much even if the temperature for heat sealing is increased. Say. In this state, some variation in seal strength is included as long as it is clearly differentiated from the rate of change in seal strength in other temperature regions.

In the present invention, the sealing strength after the heat sealing in the first heat sealing part is 2N / 25 mm width or more and 15 N / 25 mm width or less in the region where the temperature width is at least 30 ° C. or more, and the second The sealing strength after the heat sealing in the heat sealing portion may be 25 N / 25 mm width or more.
In this invention, the function of the 1st heat seal part and the 2nd heat seal part in a package is made by making the 1st heat seal part into predetermined seal strength, and making the 2nd heat seal part more than predetermined seal strength. It can be expressed appropriately.
Here, when the sealing strength in the first heat seal part becomes weaker than 2 N / 25 mm width, an external force acts during transportation of the packaging bag for storing the contents, and the first heat seal part may be unintentionally peeled off. is there. On the other hand, if the seal strength at the first heat seal portion is greater than 15 N / 25 width, the difference from the seal strength of the second heat seal portion becomes small, and the first heat seal portion may not be selectively peeled off.
Moreover, when the expression of the predetermined seal strength in the first heat seal part is a region having a temperature width of 30 ° C. or less, the first heat seal part is caused by fluctuations in heat seal conditions when forming a packaging bag, for example. There is a risk that the first heat seal part will not be unintentionally peeled off or the difference between the seal strength of the second heat seal part will be small and the first heat seal part will not be able to be peeled selectively. is there. Therefore, it is preferable that the seal strength of the first heat seal part is 2N / 25 mm width or more and 15/25 mm width or less in a region where the temperature width is at least 30 ° C. or more.
Furthermore, when the seal strength in the second heat seal part becomes weaker than 25 N / 25 mm width, for example, when the internal pressure is increased by cooking and heat sterilizing the package body containing the contents, the second heat seal part is peeled off. There is a fear. For this reason, it is preferable that the sealing strength of the second heat seal portion is 25 N / 25 mm width or more.

  The manufacturing method of the package of one aspect of the present invention is a manufacturing method for manufacturing a package by stacking the laminates of the present invention and partially heat-sealing, and heat-treating against an increase in the heat-sealing temperature. In the first relationship where the sealing strength after sealing is saturated, the step of heat-sealing the laminate in the temperature range, and the seal after heat sealing for the heat-sealing temperature in the temperature range higher than the first relationship In the second relationship in which the maximum value of the strength ratio is 1.3 N / 25 mm / ° C. or more, the step of seat-sealing the laminate in the temperature range is performed.

In the present invention, when the laminate of the present invention is overlaid and heat-sealed by heating to produce a package, heat-sealing is performed in a temperature range (first temperature range) that is the first relationship, and heat-sealing that exhibits easy peel properties And heat-sealing in a temperature range of the second relationship (second temperature region) that is higher than the first relationship to form a heat seal exhibiting tight sealing properties. Thus, for example, different foods are stored in one package, and after the first heat seal part is peeled and different foods are mixed, the second heat seal part is excised and opened, and the mixed food is taken out. A configuration that facilitates cooking and the like can be easily provided.
Here, the stacking of the stacked body includes a case where one stacked body is folded and stacked, and a case where two stacked bodies are stacked.
Moreover, either the process of heat-sealing in the temperature range of 1st relationship and the process of heat-sealing in the temperature range of 2nd relationship may implement first, and may implement simultaneously.

The top view which shows the package in one Embodiment of this invention. The graph which shows the relationship between the joining temperature and joining strength of the base film which concerns on this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the present embodiment, the package is illustrated as a bag having two storage spaces, but various forms such as a form including a container and a lid can be targeted, and there are also two storage spaces. The configuration is not limited to this, and a plurality of configurations may be used. As articles to be packaged, various articles such as medicines other than foods, medical products, stationery, and miscellaneous goods can be targeted. And although heat sealing is illustrated as joining which forms a package body from a laminated body, the welding by an ultrasonic wave etc. can be utilized, for example.

[Composition of package]
As shown in FIG. 1, the packaging body 1 is formed in a three-sided bag making method, for example, and has a bag shape in which a base film 11 that is a laminated body is overlaid and its periphery is heat-sealed. The package 1 includes a first heat seal portion 14 that divides the first storage space 12 and the second storage space 13 therein, and a second heat seal portion 15 in which the periphery of the base film 11 is heat sealed. ing.
The first storage space 12 stores, for example, seasoning liquid, and the second storage space 13 stores, for example, foodstuffs.
The first heat seal portion 14 exhibits a so-called easy peel property that can be peeled off by a relatively weak force such as an internal pressure, and the first storage space 12 and the second storage space 13 are peeled off by the separation of the first heat seal portion 14. And the seasoning liquid and the ingredients are mixed. The second heat seal portion 15 exhibits a so-called tight seal property with a relatively strong seal strength that does not peel off, for example, with an internal pressure.
The packaging body 1 can be fed with seasoning liquid, the first heat inlet portion 16 is formed and sealed after the seasoning liquid is charged, and the food can be charged. And a second charging port 17 in which a two heat seal part 15 is formed and sealed.

[Configuration of base film]
The base film 11 has a laminated structure including a base layer and a sealant layer (corresponding to the film of the present invention) laminated on the base layer. The base film 11 is not limited to two layers, and may have a multilayer structure in which various other intermediate layers, laminate layers, and the like are appropriately laminated.

(Base material layer)
For the base material layer, for example, polyolefin resin, nylon resin, polyethylene terephthalate resin or the like is used.
Polyolefin resins include polypropylene resins such as homopolypropylene (HPP), random polypropylene (RPP), and block polypropylene (BPP), high density polyethylene (HDPE), and (linear) low density polyethylene ((Linear) Low Density Polyethylene. : LDPE), linear ethylene-α-olefin copolymers, and the like are used.
Nylon 6, nylon 8, nylon 11, nylon 12, nylon 6,6, nylon 6,10, nylon 6,12, etc. can be used as the nylon resin.
Moreover, various additives, such as a coloring agent, can be suitably added to a base material layer.

(Sealant layer)
The sealant layer is a resin in which at least two polymers having different solubility parameters (δ, hereinafter referred to as sp value) ((cal / cm ³ ) ^1/2 ) and a nucleating agent are blended. It is formed with a composition. In this embodiment, two types, a component (A) and a component (B), are illustrated.
Here, the sp value (δ) is calculated according to the calculation method proposed by Fedors. Specifically, Ev (evaporation energy) and V (molar volume) in the table described in “Polym.Eng.Sci., 14 (2), 147-154 (1974)” were obtained, and It is calculated based on the equation (1).
δ = (Ev / V) ^1/2 (1)

As the component (A) which is one of the polymers, specifically, the component having the highest melting point, for example, a polyolefin resin, particularly a polypropylene polymer is preferably used.
Examples of the polypropylene polymer include homopolypropylene, polypropylene random copolymer, and polypropylene block copolymer. As the component (B) which is the other one of the polymers to be described later, suitable compatibility with the ethylene / methacrylic acid copolymer and the polyethylene copolymer which are suitably used, and the first exhibiting tight sealability. From the viewpoint of the temperature range for forming the two heat seal portion 15, the component (A) is particularly preferably a polypropylene random copolymer. The homopolypropylene and the polypropylene block copolymer have a melting point around 160 ° C. From this, the temperature at which the tight sealability is manifested in the second heat seal portion 15 is increased, which is effective when dealing with a high temperature depending on the object to be packaged and applications.
The sp value when the component (A) is a polypropylene random copolymer is 8.0.
Further, the melting point and melt flow rate (under 230 ° C. and 2160 g load) (JIS K7210) of the component (A) are appropriately set according to the target sealing characteristics such as a packaged object and application.

The compounding amount of the component (A) is 5% by mass or more and 20% by mass or less, preferably 8% by mass or more and 20% by mass or less, and particularly preferably 8% by mass or more and 15% by mass or less with respect to the total amount of the resin composition.
When the compounding amount of the component (A) is less than 5% by mass with respect to the total amount of the resin composition, the so-called island structure ratio is decreased, and easy peel properties may not be exhibited. On the other hand, when the amount of component (A) is more than 20% by mass based on the total amount of the resin composition, fusion of both components (A) and (B) is inhibited during heat sealing in the second temperature region. This is because the tight sealability may not be exhibited.
Thus, the compatibility between the easy peel property and the tight seal property can be controlled by the blending amount of the component (A) that becomes the polymer having the highest melting point.

The polymer of the component (B) exhibits an sp value different from that of the component (A).
Specifically, the absolute value of the difference between the sp values of component (A) and component (B) is preferably 0.7 or more and 1.2 or less, respectively.
Here, when | sp (A) -sp (B) | is smaller than 0.7, the compatibility between the component (A) and the component (B) is increased, and the dispersion state for expressing the required sealing characteristics May not be formed. On the other hand, when | sp (A) -sp (B) | is greater than 1.2, the compatibility between the component (A) and the component (B) decreases, and the dispersion state for expressing the required sealing properties is reduced. In addition to the instability of the dispersion state of both components, there is a risk that the film forming property of the base film 11 made of the resin composition may become unstable. For example, when polypropylene and nylon 12 (SP value = 9.9) are used for the polymer, the compatibility is remarkably deteriorated and the film forming property may be unstable. Therefore, the absolute value of the difference between the sp values of component (A) and component (B) is preferably set to 0.7 or more and 1.2 or less. For example, polypropylene (SP value = 7.9) is used as the component (A), and ethylene / methacrylic acid copolymer (SP value = 9.1) or low-density polyethylene (SP value = 8.6) is used as the component (B). Even when used, it is possible to clearly provide easy peelability and tight sealability.

Moreover, the ratio of the melt flow rate (Melt Flow Rate: MFR) (230 degreeC, 2160-g load) (JIS K7210) of the component (A) which shows an island structure with respect to the component (B) which shows a sea structure is 0.00. It is preferably 1 or more and 1.2 or less. That is, when MFR of component (A) and component (B) is MFR (A) and MFR (B), respectively, the relationship between MFR (A) and MFR (B) is 0.1 ≦ | MFR (A ) ÷ MFR (B) | ≦ 1.2.
Here, if | MFR (A) ÷ MFR (B) | is smaller than 0.1, the island portion of the sea-island structure becomes large, and there is a possibility that the required sealability cannot be expressed. On the other hand, if | MFR (A) ÷ MFR (B) | is greater than 1.2, the island portion of the sea-island structure may be reduced, and the required seal characteristics may not be exhibited. Therefore, the ratio of the MFR of the component (A) indicating the island structure to the component (B) indicating the sea structure is preferably set to 0.1 or more and 1.2 or less.

The absolute value of the difference between the melting points (MP) of the component (A) and the component (B) is preferably 35 or more and 70 or less. That is, when the melting points of component (A) and component (B) are MP (A) and MP (B), respectively, the relationship between MP (A) and MP (B) is 35 ≦ | MP (A) − MP (B) | ≦ 70, preferably 38 ≦ | MP (A) −MP (B) | ≦ 70, particularly preferably 40 ≦ | MFR (A) −MFR (B) | ≦ 70.
Here, if | MP (A) -MP (B) | is smaller than 35, the first temperature region for heat sealing for expressing easy peel properties becomes narrow, and the required sealing characteristics may not be stably exhibited. There is. On the other hand, when | MP (A) -MP (B) | is greater than 70, a film produced from the resin composition is used as a sealant layer, and a base film 11 in which this sealant layer is laminated with a base material layer is heat sealed. In this case, the melting point of the polyolefin resin, nylon resin, polyethylene terephthalate resin, etc. used as the base material layer is close to the second temperature region, and it adheres to the seal bar at the time of heat sealing, or the packaging made of the base material film 11 There is a possibility that the second heat seal portion 15 of the body 1 may be contracted. Therefore, the absolute value of the difference between the melting points of the component (A) and the component (B) is preferably set to 35 to 70, more preferably 38 to 70, and particularly preferably 40 to 70. . For example, polypropylene (melting point 135 ° C. or higher and 160 ° C. or lower) is used as component (A), and ethylene / methacrylic acid copolymer (melting point 99 ° C.) or ethylene / vinyl acetate copolymer (melting point 89 ° C.) is used as component (B). Even when such as is used, it is possible to clearly provide easy peel properties and tight seal properties.

The polymer of the component (B) can be any resin that satisfies the above conditions.
Specifically, an ethylene / methacrylic acid copolymer, a polyethylene copolymer, or the like is preferably used.

Examples of the nucleating agent (component (C)) include fatty acid metal salts, carboxylic acid metal salts, phosphate ester metal salts, rosin metal salts, talc, mica, and sorbitol derivatives. In particular, as the component (B), a fatty acid metal salt is preferable from the viewpoint of promoting uniform crystal formation of an ethylene / methacrylic acid copolymer and a polyethylene copolymer that are suitably used.
It is preferable that the compounding quantity of a component (C) is 1 to 3 mass% with respect to the resin composition whole quantity.
When the blending amount of component (C) is less than 1% by mass with respect to the total amount of the resin composition, the nucleation effect is insufficient, and thus the crystallization speed after heat sealing is slowed down. May take time. On the other hand, even if the blending amount of component (C) exceeds 3% by mass with respect to the total amount of the resin composition, the nucleation is saturated, and the cost increases as the amount of nucleating agent increases. It is because there is a possibility of doing.
Thus, the change with time in the seal characteristics can be controlled by the blending amount of the nucleating agent (component (C)).

For the resin composition constituting the sealant layer, for the purpose of improving workability in secondary processing such as production of the base film 11 or production of the package 1, for example, a lubricant or anti-blocking is used. It is possible to further add an agent or the like.
And the base film 11 can be manufactured by various methods, such as an inflation method, for example.

(Method for manufacturing packaging)
Next, the manufacturing method of a packaging bag is demonstrated.
The manufacturing method of the package 1 is manufactured using, for example, a manufacturing apparatus that forms three-sided bags, a film feeding step of feeding and overlapping the base film 11, and heat sealing the overlapping base film 11 to form a first heat seal portion. The first heat sealing step for forming 14 and the second heat sealing step for forming the second heat seal portion 15 by heat sealing the overlapping base film 11 are performed.
In the film delivery step, the base film 11 taken up by the take-up roll 62 is pulled out, overlapped so that the sealant layers face each other, and sent out.

In the first heat sealing step, the overlapping base film 11 is heat-sealed by a seal bar set in a predetermined temperature region (hereinafter referred to as a first temperature region), and the first heat seal part 14 showing easy peel properties. Form. In the first temperature region in the first heat sealing step, a layer configuration in which the component (A) constituting the sealant layer has a so-called island structure and the component (B) has a so-called sea structure is shown.
In this first temperature region, the component (A) in the crystallized state is in a state that inhibits fusion by the component (B) in the molten state, and exhibits an easy peel property that provides a relatively weak seal strength. In the first temperature range, the seal strength does not vary so much, and the seal strength is constant with respect to the so-called temperature. The region where the seal strength is saturated with respect to the increase in the temperature for heat sealing is defined as the first relationship as shown in FIG. 2, for example. In the first relationship, the constant state in which the seal strength is saturated may be substantially constant as long as it can be differentiated from the following second relationship, for example, as shown in FIG. It is within the allowable range that the value of the seal strength rises and falls within the range of ± 3 N / 25 mm.
Thus, the easy-peeling 1st heat seal part 14 is formed by heat-sealing the base film 11 in the 1st temperature range of the 1st relationship in which a sealant layer shows the layer structure of a sea-island structure.

Here, it is preferable that the seal strength of the first heat seal portion 14 exhibits a certain easy peel property in a region where the temperature width is at least 30 ° C. or more. And the seal strength is set to 2N / 25mm width or more and 15N / 25mm width or less, preferably 2N / 25mm width or more and 13N / 25mm width or less, particularly preferably 2N / 25mm width or more and 10N / 25mm width or less. That is, the composition of the resin composition of the sealant layer is set so that the seal strength of the first heat seal part 14 is 2N / 25 mm width or more and 15 N / 25 mm width or less. Specifically, the seal strength is adjusted by increasing or decreasing the blending amounts of the components (A) and (B).
When the sealing strength of the first heat seal part 14 becomes weaker than 2 N / 25 mm width, the stored contents may be unintentionally peeled off due to an external force during transportation of the packaging bag. On the other hand, if the seal strength at the first heat seal portion 14 is greater than 15 N / 25 mm width, the difference from the seal strength at the second heat seal portion 15 becomes small, and the first heat seal portion 14 may not be selectively peeled off. Because there is.

In the second heat sealing step, the overlapping base film 11 is heat sealed with a seal bar set to a temperature region (second temperature region) higher than the first temperature region, and the second heat seal portion 15 exhibiting tight sealing properties. Form. In the second temperature region in the second heat sealing step, a layer configuration in which the component (A) and the component (B) constituting the sealant layer are in a molten state is shown.
In this second temperature region, tight sealability that provides relatively strong heat strength is exhibited by the fusion of both the melted component (A) and component (B). And in this 2nd temperature area | region, the relationship whose maximum value of the ratio of the sealing strength with respect to heat seal temperature is 1.3 N / 25mm / degrees C or more is defined as a 2nd relationship. Specifically, for example, as shown in FIG. 2, the relationship between the heat seal temperature and the seal strength is directly proportional, and the maximum value of the slope of the direct proportional is 1.3 N / 25 mm / ° C. or more. Define a relationship.
In this way, the sealant layer is heat-sealed to the base film 11 in the second temperature range of the second relationship in which both the component (A) and the component (B) are melted. Part 15 is formed.

Here, the sealing strength of the second heat seal portion 15 is 25 N / 25 mm width or more, preferably 30 N / 25 mm width or more, and particularly preferably 35 N / 25 mm width or more.
When the sealing strength of the second heat seal part 15 is smaller than 25 N / 25 mm width, for example, when the internal pressure becomes high when the packaging body 1 containing the contents is cooked or heat sterilized, the second heat seal part 15 is peeled off. It is because there is a possibility of doing.

After the first heat sealing step and the second heat sealing step, the packaging body 1 on which the first heat sealing portion 14 and the second heat sealing portion 15 are formed is cut out as appropriate.
Then, a predetermined amount of material to be packaged is introduced into the obtained package 1 from the first input port 16 and the second input port 17 by a filling device (not shown), and the first input port 16 and the second input port 17 are filled with the first amount. The two heat seal part 15 is formed and sealed, and the article to be packaged is filled.

[Effects of Embodiment]
In the said embodiment, as a sealant layer of the base film 11 which comprises the package 1, the resin composition which mix | blended the polymer of the component (A) and (B) from which sp value differs, and a nucleating agent is used. ing.
For this reason, the easy peel property and tight seal property which are calculated | required can be expressed immediately after heat sealing. Therefore, for example, the difference in the heat seal situation in the package 1 can be easily determined, that is, the seal characteristics of the first heat seal portion 14 and the second heat seal portion 15 can be easily evaluated in a short time, and quality control can be easily performed. .
Furthermore, from the relationship between the temperature at which the base film 11 is heat-sealed and the layer structure of the sealant layer, the first relationship in the first temperature region and the second relationship in the second temperature region can be clearly differentiated. The easy-peeling first heat seal portion 14 formed by sealing and the tight-sealing second heat seal portion 15 can be easily formed simply by setting the heat sealing temperature.

And in the said embodiment, the absolute value of the difference of sp value of component (A) and (B) is 0.7 or more and 1.2 or less as a resin composition which comprises a sealant layer.
For this reason, when expressing the required sealing characteristics in the first heat seal part 14 and the second heat seal part 15, an appropriate dispersion state of the component (A) and the component (B) can be formed.

Moreover, in the said embodiment, the ratio of MFR of the component (A) which shows an island structure is 0.1 or more and 1.2 or less with respect to the component (B) which shows a sea structure as a resin composition which comprises a sealant layer. It is said.
For this reason, when expressing the required sealing characteristics in the first heat seal part 14 and the second heat seal part 15, an appropriate dispersion state of the component (A) and the component (B) can be formed.

Furthermore, in the said embodiment, the absolute value of the difference of melting | fusing point of component (A), (B) is 35 or more and 70 or less as a resin composition which comprises a sealant layer.
For this reason, for example, heat sealing can be easily performed by the temperature relationship between the first temperature region and the melting point.

Moreover, in the said embodiment, a component (A) and a nucleating agent are made into the predetermined compounding quantity as a resin composition which comprises a sealant layer.
Therefore, the easy-peeling first heat seal part 14 and the tight sealable second heat seal part 15 formed by heat sealing can be more easily formed, and the sealing characteristics can be stabilized immediately after the heat sealing. Can be expressed.

And in the said embodiment, crystallization is accelerated | stimulated by a nucleation action by using a fatty acid metal salt as a nucleating agent, and the sealing characteristic calculated | required immediately after heat sealing can be expressed.
In particular, when a polypropylene polymer is used as the component (A) and an ethylene / methacrylic acid copolymer is used as the component (B), the sealing properties required by a good nucleating action can be expressed well.

Moreover, in the said embodiment, the sealing strength of the 1st heat seal part 14 shall be 2N / 25mm width or more and 15N / 25mm width or less, and the seal strength of the 2nd heat seal part 15 shall be set to 25N / 25mm width or more. Yes.
For this reason, in the 1st heat seal part 14, while being able to prevent unintentional peeling, the 1st heat seal part 14 can be peeled selectively. Moreover, in the 2nd heat seal part 15, it can prevent that the 2nd heat seal part 15 peels, for example by internal pressure.

[Modification]
Although the best configuration for carrying out the present invention has been disclosed in the above description, the present invention is not limited to this. That is, the present invention has been described primarily with reference to specific embodiments, but with respect to the above-described embodiments without departing from the scope of the technical idea and object of the present invention, the material, quantity, and other details. In this configuration, those skilled in the art can make various modifications.
Accordingly, the descriptions of the materials and layer configurations disclosed above are exemplarily described for easy understanding of the present invention, and do not limit the present invention. Descriptions with names excluding some or all of the limitations are included in the present invention.

For example, the bag making method for manufacturing the package 1 is not limited to three-way bag making, and various methods such as a rotating drum type and a pillow type can be used. Moreover, as a package, it is good also as a structure provided with occlusion members, such as a zipper tape, so that it can reseal, for example, after putting in / out a package.
Also, the base film 11 can be produced by various methods such as a calendering method in addition to manufacturing by an inflation method. Further, not limited to coextrusion, for example, a film corresponding to the sealant layer and a film corresponding to the base material layer may be bonded and laminated.

The substrate film 11 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 of the resin composition of the present invention.
Furthermore, the composition of the raw material of the resin composition, the blending amount, the sp value of the components (A) and (B), the melt flow rate, the melting point, and the like are not limited to the above-described embodiment, and are appropriately set.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples. The film configuration, raw materials, preparation of test pieces, and measurement of bonding strength by heat sealing in each example were performed by the following methods.

[Examples 1-2, Comparative Examples 1-2]
A film having a three-layer structure having a sealant layer having a thickness of 12.5 μm, an intermediate layer having a thickness of 25 μm, and a laminate layer having a thickness of 12.5 μm was produced by inflation molding using the following raw materials.

<Raw material>
(Sealant layer)
Component (A): propylene-ethylene copolymer (sp value: 7.9, MFR (230 ° C., under 2160 g load): 1.3 g / 10 min, density: 0.930 g / cm ³ , melting point: 142 ° C.)
Component (B): ethylene / methacrylic acid copolymer (sp value: 9.1, MFR (under 190 ° C., 2160 g load): 3.0 g / 10 min, density: 0.930 g / cm ³ )
Ingredient (C): Nucleating agent for polyolefin (trade name: CN-002, manufactured by Riken Vitamin Co., Ltd.)

(Middle layer)
Linear low density polyethylene (MFR (190 ° C., under 2160 g load): 2.5 g / 10 min, density: 0.935 g / cm ³ ) 62% by mass, low density polyethylene (MFR (190 ° C., under 2160 g load): 2.0 g / 10 min, density 0.922 g / cm ³ ) 38% by mass

(Laminate layer)
Linear low density polyethylene (MFR (190 ° C., under 2160 g load): 2.5 g / 10 min, density: 0.935 g / cm ³ ) 100.00% by mass

<Preparation of test piece for bonding strength measurement>
A film having a three-layer structure was produced by inflation molding according to the formulation shown in Table 1 below.
The sealant layers of the obtained film were heat-sealed at each temperature with a thermal inclination tester (trade name: HG-100-2, manufactured by Toyo Seiki Seisakusho Co., Ltd.) to prepare a test piece.

<Seal strength>
Using a tensile tester (trade name: AGS-X) manufactured by Shimadzu Corporation, in accordance with the test method for T-shaped peeling in JIS K6854, the test specimens of each example were left immediately after heat sealing and one day after heat sealing. After that, the seal strength was measured. The seal strength was measured by peeling the test piece of each example in a T-shape at a tensile rate of 200 mm / min in MD.
The results are shown in Table 2 below and FIG.

<Evaluation results>
As is apparent from the measurement results shown in Table 2 and FIG. 2, in Comparative Example 1 that does not contain the nucleating agent of component (C), the sealing strength immediately after heat sealing and after standing for 1 day from heat sealing Regarding the seal strength, the shapes of the graphs of the first relationship and the second relationship were greatly different. Thus, in Comparative Example 1, it was recognized that the temperature at the boundary between the first relationship and the second relationship fluctuated greatly.
On the other hand, in Example 1 and Example 2 containing the nucleating agent of component (C), the difference in the graph shape between the first relationship and the second relationship is small, the change with time in the seal strength is small, and the seal characteristics are low. It was confirmed that it can be developed after heat sealing.

1 ... Packaging body 11 ... Base film (film, laminate)
14 …… First heat seal part 15 …… Second heat seal part

Claims (10)

At least two polymers having different solubility parameters (δ, hereinafter referred to as sp value) ((cal / cm ³ ) ^1/2 );
A resin composition comprising: a nucleating agent. The resin composition according to claim 1,
The absolute value of the difference in sp value between the at least two kinds of polymers is 0.7 or more and 1.2 or less, respectively. In the resin composition according to claim 1 or 2,
Regarding the melt flow rate of the at least two polymers (230 ° C., under a load of 2160 g) (JIS K7210), the ratio of the melt flow rate of the polymer showing an island structure to the melt flow rate of the polymer showing a sea structure Are each 0.1 or more and 1.2 or less. In the resin composition according to any one of claims 1 to 3,
The absolute value of the difference between the melting points of the at least two kinds of polymers is 35 or more and 70 or less, respectively. In the resin composition according to any one of claims 1 to 4,
One of the at least two polymers is a polyolefin polymer;
The blending amount of the polyolefin polymer is 5% by mass or more and 20% by mass or less based on the total amount of the composition,
The compounding quantity of the said nucleating agent is 1 to 3 mass% with respect to the composition whole quantity. The resin composition characterized by the above-mentioned. A film comprising the resin composition according to any one of claims 1 to 5 as a raw material. A base material layer;
The film according to claim 6 laminated on the base material layer,
The laminated body characterized by comprising. A laminated body in which the laminate according to claim 7 is overlapped and partly heat-sealed,
In the first relationship in which the sealing strength after heat sealing is saturated with respect to the increase in temperature for heat sealing, the first heat sealing part formed by heat sealing the laminate in the temperature range;
In a temperature range higher than the first relationship, the maximum value of the ratio of the sealing strength after heat sealing to the heat sealing temperature is 1.3 N / 25 mm / ° C. or more in the second relationship. A second heat seal part formed by heat sealing the laminate,
The package characterized by comprising. The package according to claim 8,
In the region where the sealing strength after the heat sealing in the first heat seal part is a temperature width of at least 30 ° C. or more, it is 2N / 25 mm width or more and 15 N / 25 mm width or less,
The package body, wherein a sealing strength after the heat sealing in the second heat sealing part is 25 N / 25 mm width or more. A manufacturing method for manufacturing a package by heat-sealing a part of the laminated body according to claim 7 and comprising:
In the first relationship in which the seal strength after heat sealing is saturated with respect to the increase in temperature for heat sealing, the step of heat sealing the laminate in the temperature range;
In a temperature range higher than the first relationship, the maximum value of the ratio of the sealing strength after heat sealing to the heat sealing temperature is 1.3 N / 25 mm / ° C. or more in the second relationship. And a step of sheet-sealing the laminate.

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