JP2018187814A - Multilayer film, and cylindrical package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer film capable of applying rapid seal welding, and hard for a film lap part to adhere to a side face of a cylindrical package by heat-welding when retort treatment.SOLUTION: The multilayer film of the present invention includes at least a surface layer (A) and a surface layer (E) as both outermost layers where the surface layer (A) and the surface layer (E) are layers containing an olefinic polymer, and having a melting point of 125°C or higher and 150°C or lower, and the sum of a mass ratio (mass%) of an antiblocking agent contained in the surface layer (A) and a mass ratio (mass%) of an antiblocking agent contained in the surface layer (E) is 1.5 mass% or more and 6.0 mass% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multilayer film and a cylindrical package using the same. In particular, the present invention relates to a multilayer film in which the film flap portion of the cylindrical package does not adhere to the trunk during retort processing and is excellent in high-speed sealing and storage.

  Conventionally, as a packaging method for processed products such as fish meat, livestock ham / sausage, cheese, sheep gourd, and wax, these packages are filled into a cylindrical film molded body in which a resin film is sealed on an envelope, and the upper and lower ends thereof. A method of ligating (sealing) is widely used. These packaging forms are generally called rocket packaging. As a film used for this type of packaging, a laminated film of a resin and a film that suppresses blocking have been developed that have properties excellent in gas barrier properties such as water vapor and oxygen and heat sealing properties.

For example, Patent Document 1 discloses a laminated film in which a heat-shrinkable film layer is laminated, and is a paste product in which 300 to 2000 ppm of antiblocking agent particles are contained in a polyolefin layer that becomes an outer side when used as a package. A packaging film is disclosed.
Patent Document 2 discloses a polypropylene film for retort having blocking resistance.
Furthermore, in Patent Document 3, a surface layer containing a propylene polymer having a melt flow rate at 230 ° C. of 0.5 g / 10 min or more and 8.0 g / 10 min or less, an adhesive layer containing a propylene polymer, A gas barrier layer containing an aromatic polyamide copolymer, an adhesive layer containing a propylene polymer, and a propylene polymer having a melt flow rate at 230 ° C. of 0.5 g / 10 min or more and 8.0 g / 10 min or less A coextruded stretched multilayer film in which the heat shrinkage stress at 120 ° C. is 1.0 MPa or more and 3.5 MPa or less.

  On the other hand, in these rocket packaging bodies, one edge portion of the film is sealed so as to protrude outside the packaging body, and the protruding edge portion (hereinafter referred to as “film flap portion”) is similar to Patent Document 4. Scratch processing is performed, and it aims at opening a package smoothly by a consumer picking a film flap part and tearing a film.

Japanese Patent No. 4273375 JP 2003-183418 A Japanese Patent No. 5130158 JP 61-142159 A

However, in the packaging body using the packaging film described in Patent Documents 1 and 3, the film flap portion of the packaging body is fused to the side surface of the packaging body during retort processing, and the film flap portion is picked for opening the packaging body. However, there is a problem that the openability is remarkably lowered.
Further, Patent Document 2 discloses a technique for preventing blocking of polypropylene for retort, but polypropylene having a high melting point has a problem of poor high-speed sealing property although it has heat resistance against retort treatment.

  In order to solve the problem that the film flap part is welded to the side surface of the package during retort processing, both the outermost layers of the packaging film, that is, the surface layer in contact with the object to be packaged and the surface layer in contact with the outside air when used as a package, have a high melting point. It is conceivable to use an olefin polymer. However, a packaging film using an olefin polymer having a high melting point needs to transmit high energy at the time of sealing, and the filling speed is significantly reduced. In addition, seal failures frequently occur, such as variations in the seal width, pinholes occurring in the seal portion or other than the seal portion, and excessive or insufficient melting of the seal portion. Such a sealing failure not only causes a reduction in commercial value due to a poor appearance, but also causes a lack of sealing strength and a decrease in sealing performance, and may cause easy peeling or rupture (puncture) during retort processing. Further, such a sealing failure is particularly noticeable in high-speed seal welding.

  Therefore, the problem to be solved by the present invention is to provide a multilayer film that can cope with high-speed seal welding, and that the film flap portion of the cylindrical package is difficult to weld to the side of the cylindrical package even during retort processing. is there.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
That is, the present invention is as follows.

(1)
A film having at least a surface layer (A) and a surface layer (E) as both outermost layers,
The surface layer (A) and the surface layer (E) are layers having an olefin polymer and a melting point of 125 ° C. or higher and 150 ° C. or lower,
The sum of the mass proportion (mass%) of the anti-blocking agent contained in the surface layer (A) and the mass proportion (mass%) of the anti-blocking agent contained in the surface layer (E) is 1.5 mass% or more 6 A multilayer film characterized by being less than or equal to 0.0% by mass.

(2)
The multilayer film according to (1), wherein a thermal shrinkage rate at 120 ° C. is 15% or more and 30% or less, and Haze is 1% or more and 30% or less.

(3)
The difference between the mass proportion of the anti-blocking agent contained in the surface layer (A) and the mass proportion of the anti-blocking agent contained in the surface layer (E) is 0% by mass or more and 0.5% by mass or less ( The multilayer film according to 1) or (2).

(4)
The multilayer film according to any one of (1) to (3) is curved in a cylindrical shape so that the surface layer (A) forms an outer peripheral surface, and the surface layer (A) and the surface layer (E) A tubular film molded body characterized in that a film flap portion is formed by fusing a portion where the layers are superposed.

(5)
(4) A cylindrical package body, characterized in that the cylindrical molded body according to (4) is filled with the contents and the openings at both ends are sealed.

(6)
The tubular package according to (5), which has been retorted.

  The multilayer film of the present invention can cope with high-speed seal welding, and the film flap portion of the cylindrical package is difficult to fuse to the side of the cylindrical package during retort processing.

It is a figure which shows typically the gas barrier property multilayer film of one Embodiment of this invention. It is sectional drawing which shows typically the cylindrical film molded object of one Embodiment of this invention. It is a figure which shows typically the cylindrical package body of one Embodiment of this invention. It is a figure which shows typically the automatic filling packaging machine which can be used for manufacture of the cylindrical package body of one Embodiment of this invention. It is a figure which shows typically the fusion | fusion by the hot air sealing means in manufacture of the cylindrical package body of one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

(Multilayer film)
The multilayer film of this embodiment is a film having at least a surface layer (A) and a surface layer (E) as both outermost layers,
The surface layer (A) and the surface layer (E) are layers having an olefin polymer and a melting point of 125 ° C. or higher and 150 ° C. or lower,
The sum of the mass proportion (mass%) of the anti-blocking agent contained in the surface layer (A) and the mass proportion (mass%) of the anti-blocking agent contained in the surface layer (E) is 1.5 mass% or more 6 0.0 mass% or less.
In the multilayer film of this embodiment, the surface layer (A) and the surface layer (E) are preferably both outermost layers. In other words, in the multilayer film of this embodiment, it is preferable that the surface layer (A) includes one surface, and the surface layer (E) includes the other surface on the back side of the one surface.
The multilayer film of the present embodiment is more stable and easier by grasping the film flap portion when opening the packaging body because the film flap portion of the cylindrical packaging body is less likely to be fused to the side surface of the cylindrical packaging body during retort processing. The package can be opened.

FIG. 1 is a cross-sectional view showing an example of a gas barrier multilayer film of the present embodiment.
The multilayer film 1 of the present embodiment only needs to have at least two layers of the surface layer (A) 2 and the surface layer (E) 6. For example, a gas barrier layer is provided between the surface layer (A) 2 and the surface layer (E) 6. 4. One or more arbitrary layers such as an adhesive layer may be provided. It is preferable that a gas barrier layer (C) 4 is further provided between the surface layer (A) 2 and the surface layer (E) 6, and an adhesive layer (B) is further provided between the surface layer (A) 2 and the gas barrier layer (C) 4. 3 and / or more preferably an adhesive layer (D) 5 between the surface layer (E) 6 and the gas barrier layer (C) 4. For example, the surface layer (A) 2 and the adhesive layer (B ) 3, gas barrier layer (C) 4, adhesive layer (D) 5 and surface layer (E) 6 are in the order described above, that is, surface layer (A) 2 / adhesive layer (B) 3 / gas barrier layer. (C) It is most preferable that it is a multilayer film laminated | stacked in order of 4 / adhesion layer (D) 5 / surface layer (E) 6.

-Surface layer (A)-
The surface layer (A) is a layer including one surface of the multilayer film of the present embodiment, and may be located on the outermost surface side in contact with the outside air in the tubular package of the present embodiment, for example, when heat sealing (for example, In addition, it functions as a sealing layer for the other surface layer (E) when heat-sealing with the other surface layer (E) during the production of the cylindrical film molded body, and inhibits moisture and gas permeation, and particularly includes a gas barrier layer in the multilayer film. In this case, the gas barrier layer has a function of suppressing the performance deterioration of the gas barrier layer and the oxidative deterioration of the contents (packaged object) caused thereby. Further, the surface layer (A) has a film flap part fused to the side surface of the cylindrical packaging body when the cylindrical packaging body is retorted (particularly, the surface layer (E) of the film flap part is the surface of the cylindrical packaging body). It is preferable to have heat resistance so as not to be fused to the surface layer (A).

In order to develop such a function, the surface layer (A) needs to contain an olefin polymer, and the melting point of the layer (A) needs to be 125 ° C. or higher and 150 ° C. or lower. The melting point of the surface layer (A) is preferably 130 ° C. or higher and 150 ° C. or lower, more preferably 135 ° C. or higher and 150 ° C. or lower. If the melting point of the surface layer (A) is 125 ° C. or higher, the cylindrical package can be used without melting by retort treatment, and if it is 150 ° C. or lower, high-speed sealing is performed when filling the cylindrical package or cylindrical film molded body. It has high-speed sealing so that it can be used for welding.
In addition, melting | fusing point can be measured based on JISK7121, More specifically, it can measure by the method demonstrated in the Example mentioned later.

  The surface layer (A) may contain an antiblocking agent, an additive described later, and the like in addition to the olefin polymer.

-Olefin polymer-
Examples of the olefin polymer include ethylene polymers and propylene polymers. The said olefin polymer may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the ethylene polymer include ordinary low density polyethylene, high density polyethylene, and ethylene-α-olefin copolymer. Examples of the ethylene-α-olefin copolymer include ethylene and α-olefins having 4 to 18 carbon atoms such as 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene. And a copolymer with at least one selected monomer. As the ethylene polymer, high-density polyethylene (HDPE) having a high melting point (for example, a melting point of 125 ° C. or higher, preferably 130 ° C. or higher) is preferable.

Examples of the propylene polymer include a propylene homopolymer, a copolymer of propylene and ethylene, a copolymer of propylene and an α-olefin having 4 to 18 carbon atoms (preferably 4 to 8 carbon atoms), propylene, and Examples thereof include a copolymer of ethylene and an α-olefin having 4 to 18 carbon atoms (preferably 4 to 8 carbon atoms), and may be either a random copolymer or a block copolymer. Examples of the α-olefin having 4 to 8 carbon atoms include 1-butene, 4-methyl-1-pentene, 1-pentene, 1-hexene, 1-octene and the like.
Among the monomer components constituting these propylene polymers, those other than propylene may be used alone or in combination of two or more. These propylene polymers may be used alone or in combination of two or more.

  The content of the olefin polymer in the surface layer (A) is not particularly limited, but is preferably 50% by mass or more and 100% by mass or less, and 70% by mass or more and 100% by mass with respect to 100% by mass of the surface layer (A). More preferably, it is less than%. When the content of the olefin polymer in the surface layer (A) is 50% by mass or more, the above-described functions can be sufficiently exhibited. Moreover, you may use together resin other than an olefin type polymer in the ratio of 50 mass% or less with respect to 100 mass% of surface layers (A).

-Anti-blocking agent-
The anti-blocking agent that can be contained in the surface layer (A) is preferably inorganic or organic heat-resistant hard spherical or irregular fine particles. For example, synthetic zeolite, diatomaceous earth, siliceous fine particles, spherical polymethyl methacrylate and the like can be mentioned.
The said antiblocking agent may be used individually by 1 type, and may be used in combination of 2 or more type. The antiblocking agent contained in the surface layer (A) and the antiblocking agent contained in the surface layer (E) may be the same or different.

  The average particle size of the anti-blocking agent is preferably 0.1 to 10 μm, more preferably 3 to 7 μm.

The sum of the mass proportion (mass%) of the anti-blocking agent contained in the surface layer (A) and the mass proportion (mass%) of the anti-blocking agent contained in the surface layer (E) is 1.5 mass% or more 6 0.0 mass% or less.
The mass ratio (mass%) of the anti-blocking agent contained in the surface layer (A) 100% by mass is the fusion between the surface layer (A) and the surface layer (E) during storage of the multilayer film, and the film flap portion during retort processing. From the viewpoint of further preventing the fusion and suppressing the haze, the content is preferably 0.5 to 3% by mass, more preferably 1 to 2.5% by mass.

-Surface layer (E)-
The surface layer (E) is a layer including one surface on the opposite side to the surface layer (A) in the multilayer film of the present embodiment, and functions as a seal layer when heat-sealing and inhibits moisture and gas permeation. In particular, when the gas barrier layer is included in the multilayer film, it has a function of suppressing the performance deterioration of the gas barrier layer and the oxidative deterioration of the contents (packaged items) caused thereby. Moreover, it is preferable that the surface layer (E) has heat resistance such that the film flap portion is not fused to the side surface of the cylindrical package body when the cylindrical package body is retorted.

In order to develop such a function, the surface layer (E) needs to contain an olefin polymer, and the melting point of the layer (E) should be 125 ° C. or higher and 150 ° C. or lower. The melting point of the surface layer (E) is preferably 130 ° C. or higher and 150 ° C. or lower, more preferably 135 ° C. or higher and 150 ° C. or lower. If the melting point of the surface layer (E) is 125 ° C. or higher, the cylindrical package can be used without melting by retort treatment, and if it is 150 ° C. or lower, high-speed sealing is performed when filling the cylindrical package or cylindrical film molded body. It has high-speed sealing so that it can be used for welding.
The melting peak temperature can be measured in accordance with JIS K7121, and more specifically can be measured by the method described in the examples described later.

  The surface layer (E) may contain an antiblocking agent, an additive described later, and the like in addition to the olefin polymer.

Specific examples of the olefin polymer of the surface layer (E) include, for example, the olefin polymer exemplified in the surface layer (A), and a suitable olefin polymer in the surface layer (A) is preferable.
The olefin polymer may be used alone or in combination of two or more. Further, the olefin polymer of the surface layer (E) may be the same as or different from the olefin polymer of the surface layer (A), but from the viewpoint of ensuring heat seal strength, it may be the same. preferable.

  The content of the olefin polymer in the surface layer (E) is not particularly limited, but is preferably 50% by mass or more and less than 100% by mass, and 70% by mass or more and 100% by mass with respect to 100% by mass of the surface layer (E). More preferably, it is less than%. If the content of the olefin polymer in the surface layer (E) is 50% by mass or more, the above-described functions can be sufficiently exhibited. Moreover, you may use together resin other than an olefin polymer in the ratio of 50 mass% or less with respect to 100 mass% of surface layers (E).

  Examples of the antiblocking agent that can be included in the surface layer (E) include the antiblocking agents exemplified in the surface layer (A), and a suitable antiblocking agent in the surface layer (A) is preferable.

  The mass proportion (% by mass) of the antiblocking agent contained in 100% by mass of the surface layer (E) is the fusion of the surface layer (A) and the surface layer (E) during storage of the multilayer film, and the film flap portion during retort processing. From the viewpoint of further preventing the fusion and suppressing the haze, the content is preferably 0.5 to 3% by mass, more preferably 1 to 2.5% by mass.

-Gas barrier layer-
The multilayer film of this embodiment is preferably used for a retort treatment application, and the retort treatment application has a gas barrier layer because it has a long-term stored food.

The gas barrier layer has a function of inhibiting the permeation of gas such as oxygen and preventing the oxidative deterioration of the contents (packaged object).
The oxygen transmission rate (OTR) of the multilayer film of the present embodiment is not particularly limited, but is 50 ml / m ² · day · MPa to 200 ml / m ² · day · MPa (measurement condition: 23 ° C., 65% RH). It is preferable. If the oxygen transmission rate (OTR) is 50 ml / m ² · day · MPa or more, the processability during the formation of the multilayer film is preferable, and if it is 200 ml / m ² · day · MPa or less, the oxygen barrier performance is preferable. The contents can be well protected.
The OTR of the multilayer film can be controlled by adjusting the thickness of the gas barrier layer (C) during production. Specifically, when the thickness of the gas barrier layer is increased, the OTR decreases, and when the thickness of the gas barrier layer is decreased, the OTR increases.

  In order to develop such a function, the gas barrier layer is not limited, but is selected from the group consisting of, for example, an aromatic polyamide copolymer, an ethylene-vinyl alcohol copolymer, and a polyvinylidene chloride copolymer. It is preferable to include at least one kind.

The content of at least one selected from the group consisting of an aromatic polyamide copolymer, an ethylene-vinyl alcohol copolymer, and a polyvinylidene chloride copolymer in the gas paria layer is not particularly limited, but the gas barrier layer is 100% by mass. On the other hand, the content is preferably 50% by mass or more and 100% by mass or less, and more preferably 70% by mass or more and 100% by mass or less.
In addition, the multilayer film of this embodiment may have two or more gas barrier layers.

-Adhesive layer (B)-
The multilayer film of this embodiment may have an adhesive layer (B) between the surface layer (A) and the gas barrier layer.
The adhesive layer (B) has a function of adhering the surface layer (A) and the gas barrier layer, and also has a function of suppressing permeation of moisture and gas.

Examples of the resin contained in the adhesive layer (B) include an ethylene vinyl acetate copolymer, an acid-modified product of an olefin copolymer, and the like. From the viewpoint of withstanding retort treatment, an acid-modified product of a propylene polymer having a melting point of 125 ° C. or higher is preferable. The resin contained in the adhesive layer (B) may be used alone or in combination of two or more.
The content of the acid-modified product of the propylene polymer in the adhesive layer (B) is not particularly limited, but is preferably 50% by mass or more and 100% by mass or less with respect to 100% by mass of the adhesive layer (B). More preferably, it is 70 mass% or more and 100 mass% or less.

Examples of the acid-modified product of the propylene polymer include those obtained by acid-modifying the above-mentioned propylene polymer with an unsaturated carboxylic acid such as maleic acid or fumaric acid or an acid anhydride by graft copolymerization. When such an acid-modified product of a propylene-based polymer is used, adjustment of the acid-modified ratio makes it easy to adjust adhesion with the surface layer (A) and the gas barrier layer, and inhibition of moisture and gas permeation. By using a propylene-based acid-modified product having a high acid modification rate, the adhesive strength with the surface layer (A) or the gas barrier layer tends to be increased.
The propylene polymer in the acid-modified product of the propylene polymer may be the same as or different from the propylene polymer in the surface layer (A), but the surface layer (A) and the adhesive layer (B) From the viewpoint of adhesiveness, it is preferable that they are the same.

  The content of the unsaturated carboxylic acid and the acid anhydride in the acid-modified product of the propylene polymer is not particularly limited, but is preferably 0.25% by mass or more, and 0.50% by mass or more. More preferred.

-Adhesive layer (D)-
The multilayer film of this embodiment may have an adhesive layer (D) between the surface layer (E) and the gas barrier layer.
Similar to the adhesive layer (B) described above, the adhesive layer (D) has a function of adhering the gas barrier layer and the surface layer (E), and also has a function of suppressing permeation of moisture and gas.

  The resin contained in the adhesive layer (D) preferably contains an acid-modified product of a propylene-based polymer from the viewpoint of easily exhibiting the above function.

  Specific examples of the resin contained in the adhesive layer (D) include, for example, propylene-based acid-modified products exemplified in the adhesive layer (B), and a suitable resin in the adhesive layer (B) is preferable. Here, the resin of the adhesive layer (D) may be the same as or different from the resin of the adhesive layer (B), but is preferably the same from the viewpoint of the peel strength between the layers. In addition, these adhesive resin may be used individually by 1 type, or may use 2 or more types together.

  The content of the acid-modified product of the propylene polymer in the adhesive layer (D) is not particularly limited, but is preferably 50% by mass or more and 100% by mass or less with respect to 100% by mass of the adhesive layer (D). More preferably, it is 70 mass% or more and 100 mass% or less.

-Additives-
Each layer such as the surface layer (A), the surface layer (E), the gas barrier layer, and the adhesive layer described above is a plasticizer, an antioxidant, a colorant, an ultraviolet absorber, a crystal nucleating agent and the like as long as the physical properties of the multilayer film are not impaired. These various additives may be included.

In the multilayer film of the present embodiment, the sum of the mass ratio (mass%) of the anti-blocking agent contained in the surface layer (A) and the mass ratio (mass%) of the anti-blocking agent contained in the surface layer (E) is From the viewpoint of making it difficult for the film flap portion of the cylindrical package to be welded to the side surface of the cylindrical package during retort treatment, it is 1.5 mass% to 6.0 mass%, preferably 2 mass% to 5 mass%. It is not more than mass%, more preferably not less than 2.5 mass% and not more than 4 mass%.
If the sum is 1.5% by mass or more, the surface layer (A) and the surface layer (E) can be prevented from fusing during the retort treatment. It has high-speed sealing so that it can cope with seal welding. Moreover, if the said sum is 5 mass% or less, since a high-speed sealing property improves further, it is more preferable.

  In the multilayer film of the present embodiment, the total mass (100 mass) of the surface layer (A) and the surface layer (E) from the viewpoint that the film flap portion of the cylindrical package is less likely to be welded to the side surface of the cylindrical package during retort processing. %) Of the total mass of the antiblocking agent contained in the surface layer (A) and the surface layer (E) is preferably 0.75 mass% or more and 3.0 mass% or less, more preferably 1. It is 0 mass% or more and 2.5 mass% or less.

In the multilayer film of the present embodiment, the difference between the mass ratio (mass%) of the anti-blocking agent contained in the surface layer (A) and the mass ratio (mass%) of the anti-blocking agent contained in the surface layer (E) ( The absolute value of the difference is preferably 0% by mass or more and 0.5% by mass or less, more preferably more than 0% by mass and 0.3% by mass or less.
If the difference is 0% by mass or more and 0.5% by mass or less, the multilayer film has a symmetrical configuration, and the film does not curl to either side after retorting.

(Physical properties of multilayer film)
Hereinafter, the physical properties of the multilayer film of this embodiment will be described.

-Thickness-
The thickness of the multilayer film is not particularly limited and can be arbitrarily set. However, considering the use for retort applications, the total thickness (total thickness) of the multilayer film is 30 to 50 μm. Preferably, it is 35-45 micrometers. In general, there is a trade-off between the occurrence frequency of bag breakage during retort processing and the openability during opening, and increasing the thickness tends to reduce the frequency of bag breakage during retort processing. If it is thin, it tends to be easily opened with an appropriate force at the time of opening. Therefore, in order to maintain both of these characteristics with a good balance, the total thickness is preferably 30 to 50 μm.

Further, the number of layers of the multilayer film is not particularly limited, but a five-layer structure centering on the gas barrier layer is preferable. Further, the thickness of each layer is not particularly limited and can be arbitrarily set. From the viewpoint of seal strength and storage stability, the thickness of each layer is, for example, the total thickness of the multilayer film as 100%. (A): 20-40%, adhesive layer (B): 5-20%, gas barrier layer (C): 5-40%, adhesive layer (D): 5-20%, surface layer (E): 20-40 % Is preferred.
Further, the surface layer (A) and the surface layer (E) may be the same or different in thickness, but the symmetrical structure of the multilayer film is maintained, and the film curls to either side after retorting. Therefore, it is preferable that the thickness is the same.

-Oxygen transmission rate (OTR)-
Multilayer film of the present embodiment is preferably the oxygen transmission rate (OTR) is not more than 50ml / m ² · day · MPa or higher ^{500ml / m 2 · day · MPa} , more preferably 200ml / m ² · day · MPa It is as follows. If the oxygen permeability is 50 ml / m ² · day · MPa or more, the workability during the formation of the multilayer film is preferred, and if it is 200 ml / m ² · day · MPa or less, the oxygen barrier performance is preferred, and the contents Can be sufficiently protected.
The oxygen transmission rate can be measured in accordance with ASTM D-3985.

-Thermal shrinkage-
The multilayer film of this embodiment preferably has a thermal shrinkage rate at 120 ° C. of 15% or more and 30% or less, and more preferably 15% or more and 25% or less.
If the heat shrinkage is 15% or more, the multilayer film fits the packaged object when it is retorted at 120 ° C for 20 minutes when the packaged object is packaged using the multilayered film, and is stored for a long time. Even when the shrinkage occurs in the article to be packaged at the time, generation of wrinkles derived from the slack of the multilayer film can be effectively suppressed. Further, since the film flap portion is prevented from coming into contact with the side surface of the package body by contracting when the retort processing is performed, the film flap portion is suppressed from being welded to the side surface of the package body when the retort processing is performed. The When the heat shrinkage is 30% or less, excessive shrinkage is suppressed when heat-sealing the multilayer film, and seal failure due to variation in seal width is suppressed.
The heat shrinkage rate at 120 ° C. of the multilayer film can be controlled by the draw ratio at the time of production, the drawing temperature, the heat treatment temperature during drawing or after drawing, and the like. Specifically, increasing the draw ratio or lowering the stretching temperature or heat treatment temperature increases the thermal shrinkage rate at 120 ° C, and decreasing the draw ratio or increasing the stretching temperature or heat treatment temperature decreases the heat shrinkage rate at 120 ° C. Tend to be.
In addition, a heat shrinkage rate means the value which averaged the heat shrinkage rate about the vertical direction and the horizontal direction of a film, and can be evaluated by the method demonstrated in the Example mentioned later.

-Haze-
The haze of the multilayer film of the present embodiment is preferably 1% or more and 30% or less, more preferably 1% or more and 15% or less from the viewpoint of contents visibility.
The haze of the multilayer film can be measured by the method described in the examples described later.

(Method for producing multilayer film)
The multilayer film of the present embodiment is preferably produced, for example, by stretching a laminate obtained by a coextrusion method. Hereinafter, as a representative example, a method for producing a multilayer film in which a surface layer (A), an adhesive layer (B), a gas barrier layer (C), an adhesive layer (D), and a surface layer (E) are laminated in this order by an inflation method. Will be described in detail.

  First, each component constituting the surface layer (A), the adhesive layer (B), the gas barrier layer (C), the adhesive layer (D), and the surface layer (E) is melted in each extruder, and the surface layer is formed using a multilayer circular die. (A) / Adhesive layer (B) / Gas barrier layer (C) / Adhesive layer (D) / Surface layer (E) are co-extruded to be solidified by applying water or warm water, and then multilayered. An annular extrudate (parison) is obtained.

  Next, the parison obtained above is heated, and air is injected under conditions suitable for imparting orientation (for example, 20 ° C. or higher and 100 ° C. or lower), and stretching is performed while forming bubbles. To produce a multilayer film. The multilayer film of this embodiment is preferably a stretched film (particularly a biaxially stretched film). In order to obtain a multilayer film having a thermal shrinkage rate at 120 ° C. of 15% or more and 30% or less, the stretching temperature is preferably set to 100 ° C. to 130 ° C., and the stretching ratio is preferably set to an area magnification of 25 to 45 times. Is preferred. Further, during or after stretching, heat set treatment such as hot air blowing, hot roll, indirect heating using an infrared heater or the like may be performed alone or in combination.

(Use of multilayer film)
The multilayer film of the present embodiment can be used for packaging articles such as foods containing components that are susceptible to oxidative degradation or transpiration. Such a multilayer film is used as a packaging material for foods that easily undergo oxidative discoloration, for example, raw meats such as beef, pork, chicken and fish, processed products such as sausages and hams, and dairy products such as butter and cheese. Can also be suitably used.

  In addition, the multilayer film of the present embodiment can be suitably used for a tubular film molded body to be described later, but also a bag-shaped packaging material, a pillow packaging material, a tray packaging material, a top seal lid material, a frozen packaging material, and a casing packaging. It can be suitably used for packaging materials for vacuum packaging and gas replacement packaging.

(Cylindrical film molding)
FIG. 2 is a cross-sectional view showing an example of the tubular film molded body of the present embodiment.
The tubular film molded body 7 of the present embodiment includes the multilayer film 1 of the present embodiment and has a film flap portion 14. In the tubular film molded body 7 of the present embodiment, the multilayer film 1 of the present embodiment is curved into a tubular shape, and the portion where the surface layer (A) 2 and the surface layer (E) 6 are superimposed is fused. Thus, the film flap portion 14 is formed.
More specifically, the tubular film molded body 7 of the present embodiment is formed by bending the multilayer film 1 of the present embodiment into a tubular shape, with both end portions 11 and 12 of the multilayer film 1 overlapping each other, The surface layer (A) at the end portion 11 of this film and the surface layer (E) at the other end portion 12 facing the one end portion are joined together to form a film flap portion 14. It is preferable that the cylindrical film molded body 7 of this embodiment is joined by at least one part (seal part 13) which overlapped one edge part 11 and the other edge part 12. As shown in FIG.
The tubular film molded body of the present embodiment has good long-term storage and good appearance, is excellent in aesthetics, and can improve the commercial value.
Moreover, the cylindrical film molded body 7 of the present embodiment has openings at both ends in the axial direction, and the contents (packaged items) can be packaged in a cylinder sandwiched between the opened ends. It can be used as a packaging material.

(Manufacturing method of cylindrical film molded body)
Although the manufacturing method of the cylindrical film molded object 7 of this embodiment is not specifically limited, For example, the multilayer film 1 of this embodiment is curved in a cylindrical shape, and the surface layer (A) 2 of one end 11 and the The surface layer (E) 6 of the other end portion 12 facing one end portion is overlapped, heat is applied to the overlapped portion, and heat welding (heat sealing) is performed, so that heat sealing is performed at the seal portion 13. The tubular film molded body 7 having the film flap portion 14 may be obtained.

As a method of heat welding, for example, a known method such as a hot plate sealing method in which a hot plate is brought into contact and sealed, a hot air sealing method in which hot air is blown and sealed, an ultrasonic sealing method, etc. can be adopted. From the viewpoint of enhancing the properties, the hot air sealing method is preferable. The hot air temperature and spraying pressure in the hot air sealing method may be set as appropriate according to the thickness, rigidity, melting point, etc. of the multilayer film 1 so that the desired heat sealing can be carried out. From the viewpoint of enhancing the properties, the hot air temperature is preferably about 280 to 430 ° C., and the spraying pressure is preferably about 0.2 to 0.6 MPa.
The sealing strength at the sealing portion 13 of the tubular film molded body 7 of the present embodiment is preferably 6 N / 15 mm width or more from the viewpoint of increasing the reliability by suppressing peeling of the sealing portion during boil and retort processing. . The seal strength can be measured by the method described in the examples described later.

(Tubular package)
FIG. 3 is a diagram schematically showing a tubular package of one embodiment of the present invention manufactured using the tubular film molded body of one embodiment of the present invention.
The cylindrical package 8 (rocket packaging type filler) of the present embodiment includes the cylindrical film molded body 7 and an article to be packaged (contents) filled in the cylindrical film molded body 7. Both end openings in the axial direction of the tubular film molded body 7 are sealed. The opening portions at both ends in the axial direction of the tubular film molded body 7 may be fused by applying ultrasonic waves, high frequencies, heat, or the like, or may be sealed using a sealing member. The sealing member is not particularly limited, and a known member such as a synthetic resin or metal wire can be used. Here, the edge portion of the film that protrudes from the seal portion 13 of the cylindrical package 8 to the outside of the package corresponds to the film flap portion 14.
The tubular package of the present embodiment has good long-term storage and good appearance, excellent aesthetics, and can improve the commercial value.

  The tubular film molded body 7 of this embodiment and the tubular package 8 in which the contents (packaged body) are enclosed are, for example, a known automatic filling and packaging machine (for example, “ADP (registered product) manufactured by Asahi Kasei Corporation”. Trademark)))). Hereinafter, the automatic filling and packaging machine 100 that can be suitably used will be described in detail with reference to the drawings.

FIG. 4 is a diagram schematically showing an automatic filling and packaging machine that can be used for manufacturing the cylindrical package of one embodiment of the present invention.
FIG. 5 is a diagram schematically showing fusion by hot air sealing means in the manufacture of the tubular package of one embodiment of the present invention.

  The automatic filling and packaging machine 100 includes a film supply unit 111, a filling unit 121, a cylinder making unit 131, a hot air sealing unit 141, and a sealing unit 151. In the present embodiment, a tubular body is formed from the strip-shaped multilayer film 1 by the film supply means 111, the tube making means 131, and the hot air sealing means 141, and the tubular film molded body 7 is formed.

  The film supply unit 111 includes feed rollers 111a and 111b, feed rollers 112a and 112b, and a drive mechanism (not shown). The film supply unit 111 is formed into a strip shape from the original roll according to the drive of the drive mechanism and the feed rollers 112a and 112b (not shown). The multilayer film 1 is continuously supplied. The supply speed of the multilayer film 1 is usually about 10 to 60 m / min, and is appropriately determined according to the type, thickness, rigidity, melting point of the multilayer film 1 to be used, and the material and viscosity of the packed object to be filled. Is set.

  The filling means 121 has a hollow cylindrical filling nozzle 122, and a feed pump 123 that supplies an article to be packed into the filling nozzle 122 is connected to the upper end of the filling nozzle 121. The filling means 121 supplies the article to be packaged into the filling nozzle 122 according to the drive of the feed pump 123.

  The tube-making means 131 has a tube-making folder 132 formed by winding a metal piece of a predetermined shape into a substantially spiral shape. The tube making folder 132 is formed so that its inner peripheral diameter is larger than the outer peripheral diameter of the filling nozzle 122, and is arranged on a substantially concentric circle with the filling nozzle 122. Therefore, the outer peripheral wall of the filling nozzle 122 and the inner peripheral wall of the tube making folder 132 are in a state of being spaced apart by a predetermined distance. And the strip | belt-shaped multilayer film 1 supplied from an original fabric roll is guide | induced to the lower surface opening from the upper surface opening of the cylinder making folder 132, and follows the spiral structure when passing the inside of the cylinder making folder 132. It is curved into a cylindrical shape, and is formed into a cylindrical body in which both end portions 11 and 12 thereof are overlapped, and is transferred downward from the bottom opening of the tube-making folder 132 in FIG.

  The hot air sealing means 141 includes a hot air application nozzle 142, a pressure adjustment mechanism and a temperature adjustment mechanism (not shown), and is arranged at a position separated from the outer peripheral wall of the filling nozzle 122 by a predetermined distance below the tube making folder 132. Has been. Hot air blows from the nozzle opening 142a of the hot air application nozzle 142 to the overlapping portion of the tubular body that has passed through the tube making folder 132 (the portion including the seal portion 13 where the both end portions 11 and 12 of the multilayer film 1 are overlapped). Then, hot air sealing is performed by fusing part of the overlapping portion (see FIG. 5). The hot air blowing pressure is measured by a pressure sensor installed in the above-described pressure adjusting mechanism (not shown), and is increased or decreased by the pressure adjusting mechanism. Further, the temperature of the hot air is measured by a temperature sensor installed in the above-described temperature adjustment mechanism (not shown), and is increased or decreased by the temperature adjustment mechanism.

From the viewpoint of improving the sealing performance, the hot air applying nozzle 142 is a position where hot air is blown from the vertical direction to the overlapping portion of the cylindrical body (to the tangential contact in the cross section of the overlapping portion), in other words, In addition, it is preferably arranged at a position where hot air can be blown from a direction substantially perpendicular to the tangent line of the overlapping portion in the cross section of the cylindrical body.
By sealing the overlapped portion with hot air, a substantially cylindrical tubular film molded body 7 is formed. The tubular film molded body 7 is filled with the article to be packaged from the filling nozzle 122 described above, and thus the tubular film molded body 7 filled with the article to be packaged is sandwiched between the feed rollers 112a and 112b. 4 is moved downward.

  The sealing unit 151 includes squeezing rollers 152 a and 152 b and a sealing mechanism 153. The sealing means 151 presses the cylindrical film molded body 7 filled with an article to be packaged from the outside at predetermined intervals by the squeeze rollers 152a and 152b, and then pushes away the article to be packaged at the pressed portion, The mechanism 153 converges and seals the multilayer film 1 in the pressed area. That is, the sealing means 151 seals both end openings corresponding to the upper and lower bases of the tubular film molded body 7. The sealing process in the sealing mechanism 153 includes a method of applying ultrasonic waves, high frequency or heat to the converging part of the multilayer film 1 and fusing it, and a converging part of the multilayer film 1 using a synthetic resin or metal wire. Known methods such as a method of ligating together and a method of using them together are adopted.

  By the above sealing treatment, both end portions of the tubular film molded body 7 are sealed, whereby the tubular packaging body 8 is manufactured. In addition, you may divide | segment the cylindrical packaging body 8 by which the both ends were sealed into each cylindrical packaging body 8 simultaneously with a sealing process, or in the subsequent cutting process. Moreover, after sealing both ends of the cylindrical film molded body 7, heat sterilization treatment (boil, retort treatment) (for example, temperature 110 to 130 ° C., pressure 0.1 to 0.4 MPa, time 20 to 40 minutes) The tubular package 8 may be obtained by retorting or the like.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited only to these Examples.
The measurement methods and evaluation methods for various performances are described below.

<(1) Melting point>
The melting peak temperature and the heat of fusion of the surface layer of the multilayer film were measured using Pyris Diamond DSC manufactured by Perkin Elmer. Only the surface layer (A) and the surface layer (E) of the multilayer film were peeled to obtain a measurement sample. First, the sample was heated from 10 ° C. to 200 ° C. at a rate of 10 ° C./min and held at 200 ° C. for 1 minute. Next, the sample was cooled to 0 ° C. at 10 ° C./min and held at 0 ° C. for 1 minute. Furthermore, the temperature corresponding to the peak value of the crystal melting curve when the sample was heated again at 10 ° C./min was defined as the melting point (melting peak temperature, Tm) (° C.).

<(2) Haze>
The HAZE (haze value) of the multilayer film was measured according to ASTM-D1003.

<(3) Oxygen permeability>
Using OX-TRAN 2/21 manufactured by MOCON, the oxygen permeation rate (ml / m ² · day · MPa) was measured according to ASTM D-3985. The value 6 hours after setting the multilayer film in the apparatus was adopted. The measurement was performed under the conditions of 23 ° C. and 65% RH. The smaller the oxygen permeability, the higher the oxygen barrier property.

<(4) Thermal shrinkage at 120 ° C.>
After cutting the multilayer film into 150 mm x 150 mm and adjusting the humidity for 24 hours under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, the sides of the multilayer film are longitudinal (MD direction) and lateral (TD direction). A square frame with a length of 100 mm on one side was attached so as to be parallel to each other. The test piece was heat treated in pressurized hot water at 120 ° C. for 20 minutes, and then the water adhering to the surface of the test piece was removed with a filter paper and left for 24 hours at a temperature of 23 ° C. and a relative humidity of 50%. The dimension L (mm) of the vertical direction and the horizontal direction of the test piece was measured, respectively. The heat shrinkage rate in the vertical direction was calculated from the following equation using the vertical direction L1 (mm).
Longitudinal heat shrinkage (%) = 100 × (100−L1) / 100
The horizontal direction heat shrinkage rate (%) is calculated in the same manner as the vertical direction heat shrinkage rate using the horizontal dimension L2, and the average value of the vertical direction heat shrinkage rate and the horizontal direction heat shrinkage rate is calculated. The heat shrinkage rate (%) at 120 ° C.

<(5) High speed sealing performance>
The various setting conditions of the automatic filling and packaging machine are shown below.
Film speed: 41 m / min Number of shots: 180 lines / min Nozzle opening 142a: Length 55 mm, width 0.3 mm
Hot air temperature: 280 ° C to 430 ° C (inside the nozzle)
Hot air pressure: 0.43 MPa (inside the nozzle)
From the range of seal temperature (hot air temperature) at which stable sealing can be performed when filling, high-speed sealing performance was evaluated according to the following criteria.
○ (Good): Seal temperature range is 15 ° C or more △ (Normal): Seal temperature range is 5 ° C or more and less than 15 ° C x (Inferior): Seal temperature range is less than 5 ° C Here, a stable seal means A seal that satisfies both the seal strength criteria and sealability criteria.
(Seal strength)
A strip-shaped test piece having a width of 15 mm and a length of 60 mm is prepared from 20 cylindrical film molded bodies. Then, using Tensilon universal testing machine (trade name: RTC-1210, manufactured by Orientec Co., Ltd.), both ends in the longitudinal direction of the obtained test piece are fixed to the film chuck part, and the distance between chucks is 10 mm, 180 ° peeling, The seal strength is measured under the condition of a tensile speed of 500 mm / min. The seal strength is an average of 20 test pieces, and if the average is 6 N / 15 mm width or more, the molded body is assumed to have a seal that satisfies the standard of seal strength.
(Sealability)
Visually observe the seal part of 20 cylindrical film moldings and jump to the seal part (where the seal part is not thermally welded) and one pin hole (perforation of the seal part due to excessive melting) exists in the seal part Otherwise, it is assumed that the molded body has been sealed to satisfy the sealability standard.

<(6) Retort weldability of film flap part>
About 20 cylindrical packaging bodies, the retort processing is performed at 120 ° C. for 20 minutes under the condition that the gauge pressure in the heating can is 0.25 MPa, and the film flap portion of the cylindrical packaging body after the retorting treatment is the cylindrical packaging. The number of parts that were even partially welded to the side of the body was counted and evaluated according to the following criteria.
◯ (Excellent): Number of welds between the film flap and the side of the cylindrical package is 0. △ (Good): Number of welds between the film flap and the side of the cylindrical package is 1. Or 2 x (Inferior): The number of occurrence of welding between the film flap and the side surface of the cylindrical package is 3 or more

<(7) Curling of film flap part>
About 20 cylindrical packaging bodies, the retort processing is performed at 120 ° C. for 20 minutes under the condition that the gauge pressure in the heating can is 0.25 MPa, and the film flap portion of the cylindrical packaging body after the retorting treatment is applied to the trunk body. The number of those curled toward the inner surface or the outer surface, not parallel, was counted and evaluated according to the following criteria.
○ (Good): The number of curl occurrences in the film flap part is 0 or more and 2 or less. △ (Normal): The number of curl occurrences in the film flap part is more than 2

  Table 1 shows the resins and trade names used in the examples and comparative examples.

[Example 1]
After melt coextrusion using a cyclic 5-layer die with the resin compositions and additives shown in Tables 1 and 2, it was solidified with cold water at 15 ° C. to produce a tube-shaped unstretched original fabric having a total thickness of 1100 μm. Then, the unstretched original fabric was biaxially stretched at a stretching temperature of 115 ° C. and stretched at a stretching ratio of 30 times that was 5.0 times in the machine direction (MD direction) and 6.0 times in the transverse direction (TD direction) by an inflation method. After stretching, the multilayer film having a final thickness of 40 μm was obtained by heat treatment with a heating roll at 90 ° C. And after winding up the obtained multilayer film, it cut | judged to 100 mm in width, unwinding. Furthermore, the multilayer film of Example 1 was produced by winding up the multilayer film again.
The obtained multilayer film had an oxygen permeability of 100 ml / m ² · day · MPa (23 ° C., 65% RH), and exhibited sufficient barrier performance for long-term storage.
Next, using a hot air sealing type automatic filling and packaging machine ("ADP (registered trademark)" manufactured by Asahi Kasei Co., Ltd.), the multilayer film of Example 1 is made into a cylinder so that the outer layer (A) constitutes the outer peripheral surface. It was curved in a cylindrical shape through a folder, and the surface layer (E) at the other end facing the one end was superimposed on the surface layer (A) at one end. Next, hot air was blown from the surface layer (A) side to the overlapped portion, and heat sealing was performed on the envelope, thereby producing a tubular film molded body having a folding width of 40 mm. Subsequently, the fish sausage raw material surimi was filled into the tubular film molded body from the filling nozzle, and then both ends were ligated and sealed with aluminum wires to obtain a tubular package having a length of 200 mm. Table 2 shows the evaluation results of various performance evaluations. Various settings of the automatic filling and packaging machine are as described above.

[Example 2]
Except having used for the resin composition and additive which are shown to Table 1, 2, it processed similarly to Example 1, and obtained the multilayer film of Example 2, the cylindrical film molded object, and the cylindrical package. Table 2 shows the evaluation results of various performance evaluations.

[Example 3]
Except having used the resin composition and additive shown to Table 1, 2, it processed similarly to Example 1, and obtained the multilayer film of Example 3, the cylindrical film molded object, and the cylindrical package. Table 2 shows the evaluation results of various performance evaluations.

[Example 4]
Except having used the resin composition and additive shown to Table 1, 2, it processed similarly to Example 1, and obtained the multilayer film of Example 4, the cylindrical film molded object, and the cylindrical package. Table 2 shows the evaluation results of various performance evaluations.

[Example 5]
Using the resin composition and additives shown in Tables 1 and 2 except that the stretching temperature was set to 120 ° C., the same treatment as in Example 1 was performed, and the multilayer film, cylindrical film molded body, and cylindrical shape of Example 5 were processed. A package was obtained. Table 2 shows the evaluation results of various performance evaluations.

[Example 6]
Using the resin composition and additives shown in Tables 1 and 2, the same procedure as in Example 1 was conducted except that the stretching temperature was 123 ° C., and the multilayer film, cylindrical film molded body and cylindrical shape of Example 6 were processed. A package was obtained. Table 2 shows the evaluation results of various performance evaluations.

[Example 7]
Using the resin composition and additives shown in Tables 1 and 2 except that the stretching temperature was set to 105 ° C., the same procedure as in Example 1 was carried out to obtain the multilayer film, cylindrical film molded body and cylindrical shape of Example 7. A package was obtained. Table 2 shows the evaluation results of various performance evaluations.

[Example 8]
Except having used the resin composition and additive shown to Table 1, 2, it processed similarly to Example 1, and obtained the multilayer film of Example 8, the cylindrical film molded object, and the cylindrical package. Table 2 shows the evaluation results of various performance evaluations.

[Example 9]
Except having used the resin composition and additive shown in Table 1, 2, it processed similarly to Example 1, and obtained the multilayer film of Example 9, the cylindrical film molded object, and the cylindrical package. Table 2 shows the evaluation results of various performance evaluations.

[Example 10]
Using the resin composition and additives shown in Tables 1 and 2 except that the stretching temperature was set to 110 ° C., the same treatment as in Example 1 was performed, and the multilayer film, cylindrical film molded body, and cylindrical shape of Example 9 were processed. A package was obtained. Table 2 shows the evaluation results of various performance evaluations.

[Example 11]
Using the resin composition and additives shown in Tables 1 and 2 except that the stretching temperature was 112 ° C., the same treatment as in Example 1 was carried out to obtain the multilayer film, cylindrical film molded body and cylindrical shape of Example 11 A package was obtained. Table 2 shows the evaluation results of various performance evaluations.

[Comparative Example 1]
With the resin composition and additives shown in Tables 1 and 3, the same treatment as in Example 1 was performed to obtain a multilayer film, a tubular film molded body, and a tubular package of Comparative Example 1. Table 3 shows the evaluation results of various performance evaluations.

[Comparative Example 2]
A multilayer film of Comparative Example 2 was obtained in the same manner as in Example 1 with the resin composition and additives shown in Tables 1 and 3. In high-speed sealing with ADP, seal jumping occurred frequently, and a cylindrical film molded body could not be produced. Table 3 shows the evaluation results of various performance evaluations.

[Comparative Example 3]
A multilayer film of Comparative Example 3 was obtained in the same manner as in Example 1 except that the resin compositions and additives shown in Tables 1 and 3 were used and the stretching temperature was 120 ° C. With high-speed sealing with ADP, the amount of heat is insufficient and sealing cannot be performed, and a tubular film molded body cannot be produced. Table 3 shows the evaluation results of various performance evaluations.

[Comparative Example 4]
A multilayer film of Comparative Example 4 was obtained in the same manner as in Example 1 except that the resin compositions and additives shown in Tables 1 and 3 were used and the stretching temperature was set to 108 ° C. Table 3 shows the evaluation results of various performance evaluations.

[Comparative Example 5]
A trace experiment was conducted with an addition amount of 2000 ppm of the antiblocking agent of Example 1 of Japanese Patent No. 4273375. A multilayer film of Comparative Example 5 was obtained in the same manner as in Example 1 except that the resin compositions and additives shown in Tables 1 and 3 were used and the stretching temperature was 125 ° C. After retorting, it was confirmed that the film flap of the rocket package was fused vigorously.

  As can be seen from Tables 2 and 3, the multilayer film of the present embodiment was able to cope with high-speed seal welding, and was able to suppress welding of the film flap portion of the package to the side of the package even during retort processing.

  The multilayer film of the present embodiment, and the tubular film molded body and the tubular package using the multilayer film can cope with high-speed seal welding at the time of heat sealing, and the film flap portion of the packaging body is packaged even during retort processing. Since it is not fused to the side of the body, it has high openability, long-term storage, good appearance, good aesthetics, and improved product value, so it can be used widely and effectively in food and other packaging applications. And can be used particularly effectively in applications that require high temperature and pressure sterilization such as retort treatment.

DESCRIPTION OF SYMBOLS 1 Multilayer film 11 One edge part 12 of a multilayer film The other edge part 13 of a multilayer film Seal part 14 Film flap part 2 Surface layer (A)
3 Adhesive layer (B)
4 Gas barrier layer (C)
5 Adhesive layer (D)
6 Surface (E)
7 Cylindrical film molded body 8 Cylindrical packaging body 100 Automatic filling and packaging machine 111 Film feeding means 111a Feeding roller 111b Feeding roller 112a Feeding roller 112b Feeding roller 121 Filling means 122 Filling nozzle 123 Feed pump 131 Tube making means 132 Tube making folder 141 Hot air sealing means 142 Hot air applying nozzle 142a Nozzle opening 151 Sealing means 152a Squeezing roller 152b Squeezing roller 153 Sealing mechanism

Claims (6)

A film having at least a surface layer (A) and a surface layer (E) as both outermost layers,
The surface layer (A) and the surface layer (E) are layers having an olefin polymer and a melting point of 125 ° C. or higher and 150 ° C. or lower,
The sum of the mass proportion (mass%) of the anti-blocking agent contained in the surface layer (A) and the mass proportion (mass%) of the anti-blocking agent contained in the surface layer (E) is 1.5 mass% or more 6 A multilayer film characterized by being less than or equal to 0.0% by mass.   The multilayer film according to claim 1, wherein the thermal shrinkage at 120 ° C is 15% or more and 30% or less, and Haze is 1% or more and 30% or less.   The difference between the mass proportion of the anti-blocking agent contained in the surface layer (A) and the mass proportion of the anti-blocking agent contained in the surface layer (E) is 0% by mass or more and 0.5% by mass or less. Item 3. The multilayer film according to Item 1 or 2.   The multilayer film according to any one of claims 1 to 3, wherein the surface layer (A) is curved in a cylindrical shape so as to constitute an outer peripheral surface, and the surface layer (A) and the surface layer (E) are overlapped. A tubular film molded body characterized in that a film flap portion is formed by fusing the combined portions.   A cylindrical package body, characterized in that the cylindrical film molded body according to claim 4 is filled with contents, and both end openings are sealed.   The cylindrical package according to claim 5, which has been retorted.

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