JP5779428B2 - Multilayer film, tubular film molded body, and tubular packaging body - Google Patents

Description

  The present invention relates to a multilayer film, a tubular film molded body and a tubular packaging body using the multilayer film, and in particular, can be suitably used as a packaging body or a film casing for fish meat, livestock meat ham and sausage, in terms of storage stability and slipperiness. The present invention relates to an excellent multilayer film, a tubular film molded body and a tubular package using the same.

  Conventionally, as a packaging method for processed products such as fish meat, livestock hams and sausages, dairy products such as cheese and butter, or confectionery such as sheepskin and jelly, these packages are encapsulated with resin films (packaging films). A method of filling a cylindrical film molded body that has been sealed and then ligating (sealing) its upper and lower ends is widely used. As a resin film used for this type of packaging, a polyvinylidene chloride film has been widely adopted. However, in recent years, materials that do not contain chlorine tend to be required from the viewpoint of reducing environmental burden.

  For example, Patent Document 1 includes at least three layers of both outer layers made of the same type of polyolefin resin and a gas barrier intermediate layer made of polyamide resin, and the heat shrinkage stress at 50 ° C. is both in the vertical and horizontal directions. A stretched multilayer film casing is described in which a stretched multilayer film having a thermal shrinkage of 2 MPa or less and a 90 ° C. hot water shrinkage of 5 to 20% is back-seamed with both outer layers.

  Furthermore, Patent Document 2 discloses a multilayer plastic having heat shrinkability and gas barrier properties provided with a polyolefin resin layer on a surface that comes into contact with food to be packaged, and is in contact with a packaging material of the polyolefin resin layer. The food packaging material is characterized in that the surface to be treated is subjected to corona discharge treatment, and the polyolefin resin layer is premixed with an antiblocking agent.

Further, Patent Document 3 discloses a seamless tube-like multilayer plastic film having a heat shrinkability and a gas barrier property having a polyolefin resin layer as an innermost layer that comes into contact with food to be packaged, and the polyolefin resin layer. The surface in contact with the food is corona discharge treated with a wetting tension of 37 dynes / cm or more, and the treated surface adheres an antiblocking agent having an average particle size of 5 to 50 μm in the range of 0.3 to 3.5 g / m ^2. The food packaging material characterized by being made is described.

  Further, Patent Document 4 discloses a synthetic sausage casing including an outer polyamide layer, an inner polyolefin layer, and a multilayer tube constituted by an intermediate layer for bonding the inner and outer layers to each other. , Propylene, or a copolymer comprising linear alpha-olefin units having 4 to 8 carbon atoms, or consisting of a mixture of these copolymers, and the polyolefin layer is subjected to corona discharge treatment. A sausage casing is described, characterized in that it is not.

  On the other hand, high-frequency sealing, hot plate sealing, and the like are known as sealing methods for resin films. In recent years, an attempt has been made to adopt a hot air sealing method as a sealing method capable of sealing without contact. For example, Patent Document 5 describes a packaging method in which a resin film of this type is heat-sealed by being overlapped on an envelope or on a palm.

JP 2000-37828 A Japanese Patent No. 3012980 Japanese Patent No. 3148821 Japanese Patent No. 3204995 JP-A-5-316933

  However, in a package using the above-described conventional packaging film, a so-called water separation phenomenon may occur in which moisture or the like that comes out of the package is accumulated after long-term storage for about several months. On the other hand, corona treatment is applied to the surface of the film that comes into contact with the object to be packaged, and the water separation phenomenon can be prevented by bringing the object to be packaged into close contact with the film, but the object to be packaged (especially soft food such as meat) When the film in contact with the film is peeled off, the packaged material may adhere to the film excessively and the commercial value may be reduced.

  In order to solve this problem, it is conceivable that the amount of corona treatment on the film is reduced and the packaged material is not excessively adhered. However, in order to reduce the amount of corona treatment, it is difficult to control the treatment, and it takes time and effort for management, and further capital investment is required for stabilization, which places a burden on cost. .

  The present invention has been made in view of such circumstances, and when the film in contact with the package object is peeled off, the package object can be prevented from excessively adhering to the film and subjected to corona treatment. It aims at providing the multilayer film which can suppress generation | occurrence | production of a water separation phenomenon, a cylindrical film molded object, and a cylindrical package.

  As a result of earnestly examining the above problems, the present inventors have found that a multilayer film having a laminated structure made of a specific material and having a dynamic friction coefficient between surface layers in a specific range without performing corona treatment is a cylinder. The present invention has been completed by finding that there is little adhesion of the package to the film when the film is peeled off while suppressing the water separation phenomenon after long-term storage.

That is, the present invention provides the following (1) to (4).
(1) Surface layer (A), adhesive layer (B) containing an acid-modified olefin copolymer, gas barrier layer (C) containing an aromatic polyamide polymer, and an adhesive containing an acid-modified olefin copolymer Layer (D) and surface layer (E) are laminated in this order,
In the surface layer (A), the content of the olefin polymer is 60% by mass or more, an acid-modified olefin copolymer, an ethylene-aliphatic unsaturated carboxylic acid copolymer, and ethylene-aliphatic unsaturation. The content of at least one selected from a carboxylic acid ester copolymer and an acid-modified product thereof is 40% by mass or less,
In the surface layer (E), the content of the olefin polymer is 60 to 99% by mass, the acid-modified olefin copolymer, the ethylene-aliphatic unsaturated carboxylic acid copolymer, and the ethylene-aliphatic non-aliphatic copolymer. The content of at least one selected from a saturated carboxylic acid ester copolymer and an acid-modified product thereof is 1 to 40% by mass,
The multilayer film whose dynamic friction coefficient of the said surface layer (A) measured based on JISK7125 and the said surface layer (E) is 0.10-0.30.
(2) The olefin polymer of the surface layer (A) is a propylene polymer,
In the above (1), the acid-modified olefin copolymer of the adhesive layer (B) and the acid-modified olefin copolymer of the adhesive layer (D) are acid-modified propylene copolymers. Multilayer film.
(3) The multilayer film according to (1) or (2) is curved in a cylindrical shape,
A tubular film molded body in which both end portions of the multilayer film overlap and are joined to each other.
(4) The tubular film molded body according to (3) above and a packaged article filled in the tubular film molded body,
A cylindrical package in which both ends of the cylindrical film molded body are sealed.

  According to the multilayer film of the present invention, when the multilayer film has the above-described configuration, it is possible to prevent the object to be packaged from excessively adhering to the film when peeling the film in contact with the object to be packaged. Occurrence of the water separation phenomenon can be suppressed without performing the treatment. Moreover, according to the multilayer film of this invention, while being excellent in the running property (slidability) of the film at the time of continuous high-speed filling, when making it into a cylindrical film molded object, the stable sealing performance can be expressed. Furthermore, according to this invention, when peeling the film which contacted the to-be-packaged object, it can suppress that a to-be-packaged object adheres to a film excessively, while there exists moderate resistance. Further, according to the present invention, it is possible to realize a tubular film molded body and a tubular package that are attractive and have a beautiful appearance.

It is drawing which shows the principal part structure of an automatic filling packaging machine typically. It is drawing for demonstrating the method of a hot-air seal.

  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 includes a surface layer (A), an adhesive layer (B), a gas barrier layer (C), an adhesive layer (D), and a surface layer (E) in this order, and these layers are laminated in this order. .

  The surface layer (A) is positioned as a layer on one main surface side of the multilayer film of the present embodiment, and the surface layer (E) is positioned as a layer on the other main surface side of the multilayer film of the present embodiment. Yes. The surface layer (A) and the surface layer (E) function as a sealing layer at the time of heat sealing, impede the permeation of moisture and gas, reduce the performance of the gas barrier layer (C), and contents caused by this (packaging) It has a function of suppressing oxidative degradation of the product. The surface layer (A) can be used as the outermost layer in the cylindrical package, and the surface layer (E) can be used as the innermost layer in the cylindrical package. When the surface layer (E) is used as the innermost layer, it also has a function of improving the adhesion to the package and preventing the water separation phenomenon during long-term storage for about several months. In the cylindrical package, the surface layer (A) may be used as the innermost layer, and the surface layer (E) may be used as the outermost layer.

  In order to express such a function, the surface layer (A) is composed of an olefin polymer (a) or an olefin resin composition (F), and the surface layer (E) is composed of an olefin resin composition (F). Become. The olefin resin composition (F) contains an olefin polymer (a) and a predetermined copolymer (b) described later.

  Here, the olefin polymer (a) is, for example, an ethylene homopolymer, an ethylene polymer such as a copolymer of ethylene and an α-olefin having 4 to 8 carbon atoms, a propylene homopolymer, propylene and ethylene. And a propylene polymer such as a copolymer of propylene and an α-olefin having 4 to 8 carbon atoms, a copolymer of propylene, ethylene and an α-olefin having 4 to 8 carbon atoms, Either a random copolymer or a block copolymer may be used.

  Specific examples of the α-olefin having 4 to 8 carbon atoms include, for example, 1-butene, 4-methyl-1-pentene, 1-pentene, 1-hexene, 1-octene, and the like. Not.

  The olefin polymer (a) may be used alone or in combination of two or more. Among these, from the viewpoint of slipperiness and sealing properties, propylene-based polymers such as propylene-ethylene copolymer and propylene-ethylene-1-butene copolymer can be preferably used.

  The value represented by weight average molecular weight (Mw) / number average molecular weight (Mn) in the olefin polymer (a) is preferably 1.5 to 3.5 from the viewpoint of stretchability. More preferably, it is -3.0. The melting point of the olefin polymer (a) is preferably 90 ° C. to 170 ° C. from the viewpoints of heat resistance and sealing temperature in the heat sterilization treatment (boil, retort treatment).

  The olefin resin composition (F) used for the surface layer (A) and / or the surface layer (E) comprises an olefin polymer (a), an acid-modified olefin copolymer, and an ethylene-aliphatic unsaturated carboxylic acid copolymer. And a copolymer, and at least one copolymer (b) selected from an ethylene-aliphatic unsaturated carboxylic acid ester copolymer and an acid-modified product thereof.

  The acid-modified olefin copolymer in the copolymer (b) is an olefin polymer (a) described above, an unsaturated carboxylic acid such as maleic acid or fumaric acid, or an acid anhydride such as maleic anhydride. It means an acid-modified ethylene copolymer or an acid-modified propylene copolymer that is acid-modified with a product. The ethylene-aliphatic unsaturated carboxylic acid copolymer and the ethylene-aliphatic unsaturated carboxylic acid ester copolymer are ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid copolymer. Ionomer resin in which molecules such as coalescence are cross-linked with metal ions, ethylene-acrylic acid ester (selected from components of C1-C8 alcohol such as methyl, ethyl, propyl, butyl) copolymer, ethylene-methacrylic acid An ester (selected from components of alcohols having 1 to 8 carbon atoms such as methyl, ethyl, propyl and butyl) means a copolymer. The acid-modified product of ethylene-aliphatic unsaturated carboxylic acid ester copolymer refers to the above-mentioned ethylene-aliphatic unsaturated carboxylic acid ester copolymer, unsaturated carboxylic acid such as maleic acid or fumaric acid, or maleic anhydride Means an acid-modified product with an acid anhydride.

  Of these, ethylene-ethyl acrylate copolymer and ethylene-propylene copolymer-modified maleic anhydride are preferred from the viewpoints of adhesion to the package and slipperiness, and ethylene-propylene copolymer. A combined maleic anhydride-modified product is more preferred.

  The content of the olefin polymer (a) in the surface layer (A) is 60% by mass or more based on the entire surface layer (A). When the surface layer (A) is composed of the olefin resin composition (F), the content of the olefin polymer (a) in the surface layer (A) is preferably 60 to 99% by mass based on the entire surface layer (A). 70-99 mass% is more preferable. The content of the olefin polymer (a) in the surface layer (E) is 60 to 99% by mass, preferably 70 to 99% by mass, and more preferably 80 to 99% by mass based on the entire surface layer (E). .

  The content of the copolymer (b) in the surface layer (A) needs to be 40% by mass or less, preferably 30% by mass or less, more preferably 20% by mass or less, based on the entire surface layer (A). preferable. When the surface layer (A) is composed of the olefin resin composition (F), the content of the copolymer (b) in the surface layer (A) is preferably 1% by mass or more based on the entire surface layer (A). The mass% or more is more preferable.

  The content of the copolymer (b) in the surface layer (E) is the entire surface layer (E) from the viewpoint of preventing an object to be packaged (for example, meat) from excessively adhering to the multilayer film of the present embodiment. It is necessary that the amount be 40% by mass or less, preferably 30% by mass or less, and more preferably 20% by mass or less. The content of the copolymer (b) in the surface layer (E) needs to be 1% by mass or more based on the entire surface layer (E) from the viewpoint of appropriate adhesion with the packaged object, 3 mass% or more is preferable and 5 mass% or more is more preferable.

  In the multilayer film of this embodiment, the coefficient of dynamic friction between the surface layer (A) and the surface layer (E) is 0.10 to 0.30, preferably 0.10 to 0.25, and 0.10 to 0.20. More preferred. The dynamic friction coefficient is measured according to JIS K7125. In the multilayer film of this embodiment, the surface layer (A) is composed of the olefin polymer (a) or the olefin resin composition (F) containing a predetermined amount of the olefin polymer (a), and the surface layer (E ) Comprises the olefin resin composition (F) containing a predetermined amount of the olefin polymer (a), the dynamic friction coefficient between the surface layer (A) and the surface layer (E) becomes 0.10 to 0.30. It is easy and has a suitable slipperiness of the film. When a cylindrical film molded body is produced, when the film (for example, the surface layer (A) and the surface layer (E)) is stacked and sealed, the film shifts or the film runs. A stable seal can be realized without becoming unstable.

  If the content of the copolymer (b) in the surface layer (E) is less than 1% by mass, the coefficient of dynamic friction tends to be less than 0.10, the slipperiness of the film is too good, and the stacked films may be displaced. The running performance becomes unstable, and the unevenness of the seal line tends to increase. When the content of the copolymer (b) in at least one layer of both surface layers exceeds 40% by mass, the dynamic friction coefficient tends to exceed 0.30, the slipping property of the film becomes too bad, and the film is running. Pulsation tends to cause unevenness in the seal line. Increased unevenness in the seal wire also causes unevenness in the seal strength. When it is made into a tubular film molded body or tubular package, the bag is broken from the sealed part during heat sterilization treatment (boil, retort treatment). Problems are likely to occur.

  Tubular so that the surface layer (A) comprising the olefin polymer (a) or the olefin resin composition (F) or the surface layer (E) containing the olefin resin composition (F) is in contact with the package. By using a film molded body or a cylindrical package body, the film and the packaged object exhibit appropriate adhesiveness, and can prevent water separation during long-term storage of about several months.

  The adhesive layer (B) and the adhesive layer (D) have a function of adhering the surface layer (A) or the surface layer (E) and the gas barrier layer (C) and a function of suppressing permeation of moisture and gas. In order to express such a function, the adhesive layer (B) and the adhesive layer (D) are configured to include an acid-modified olefin copolymer.

  When such an acid-modified olefin copolymer is used, the adhesiveness between the surface layer (A) or the surface layer (E) and the gas barrier layer (C), moisture and gas permeability can be adjusted by adjusting the acid-modified ratio. The adjustment becomes easier. By using an acid-modified olefin copolymer having a high acid modification ratio, the adhesive strength between the surface layer (A) or the surface layer (E) and the gas barrier layer (C) tends to be increased.

  The acid-modified olefin copolymer of the adhesive layer (B) and the adhesive layer (D) is, for example, an unsaturated carboxylic acid such as maleic acid or fumaric acid or maleic anhydride, etc. Examples include acid-modified ethylene copolymers and acid-modified propylene copolymers obtained by graft copolymerization of acid anhydrides, but are not particularly limited thereto. The propylene-ethylene copolymer exemplified in the surface layer (A) and / or the surface layer (E) from the viewpoint of adhesion between the surface layer (A) or the surface layer (E) and the gas barrier layer (C) and suppression of permeation of moisture and gas. An acid-modified propylene copolymer in which a propylene copolymer such as propylene-ethylene-1-butene copolymer is modified with maleic anhydride is preferable, and an acid modification in which the propylene-ethylene copolymer is modified with maleic anhydride. A propylene-based copolymer is more preferable. These acid-modified olefin copolymers may be used alone or in combination of two or more. Further, the acid-modified olefin copolymer of the adhesive layer (B) and the acid-modified olefin copolymer of the adhesive layer (D) may be the same or different from each other.

  The adhesive layer (B) or the adhesive layer (D) can be composed only of the acid-modified olefin copolymer, and in this case, the configuration is simplified, and the productivity and economy are improved. The adhesive layer (B) or the adhesive layer (D) may contain other components in addition to the acid-modified olefin copolymer, for example, the olefin polymer (a) described above. May be included. When the olefin polymer (a) is blended in this way, the water barrier property is enhanced and the adhesion strength between the surface layer (A) or the surface layer (E) and the gas barrier layer (C) is easily adjusted.

  In this case, it is preferable that each use ratio is 20 to 50% by mass of the olefin polymer (a) and 50 to 80% by mass of the acid-modified olefin copolymer based on the whole of each adhesive layer. . When the ratio of the acid-modified olefin copolymer is increased, the adhesion tends to be improved.

  The gas barrier layer (C) has a function of preventing the oxidative deterioration of the contents (packaged object) by inhibiting the permeation of gas such as oxygen. In order to express such a function, the gas barrier layer (C) is configured to include an aromatic polyamide polymer.

  Here, the aromatic polyamide polymer means crystalline nylon (polyamide) having an aromatic ring in the main chain, and specific examples thereof include, for example, polycondensation of metaxylylenediamine and adipic acid. Polymetaxylylene adipamide (nylon MXD6) obtained by the above, polycondensate of metaxylylenediamine, adipic acid and isophthalic acid, and the like.

  Aromatic polyamide polymer is superior to aliphatic nylon such as nylon 6 and nylon 6/66 in that it has excellent gas barrier properties, low water absorption, less deterioration in gas barrier properties during water absorption, and pin resistance. Since the strength such as hole property, stretchability, molding processability, and the like are good, it is suitably used as a material constituting the gas barrier layer (C) of the present embodiment.

  A gas barrier layer (C) can be comprised only from an aromatic polyamide-type polymer, in this case, a structure becomes simple and productivity and economical efficiency are improved. The gas barrier layer (C) may contain other components as necessary in addition to the aromatic polyamide polymer.

  Each layer of (A) to (E) described above contains various additives such as plasticizers, antioxidants, colorants, ultraviolet absorbers, lubricants (including waxes), inorganic fillers, crystal nucleating agents (talc, etc.). May be included.

  The thickness of the multilayer film is not particularly limited and can be arbitrarily set, but considering the use for fish, livestock ham, and sausage, the total thickness (total thickness) of the multilayer film is 30 to 30. It is preferable that it is 50 micrometers.

  In general, there is a trade-off between the occurrence frequency of bag breakage during heat sterilization treatment such as retort treatment and the openability during opening, and increasing the thickness reduces the occurrence frequency of bag breakage during retort treatment. There is a tendency, and if the thickness is reduced, 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.

  In addition, the thickness of each layer of the multilayer film is not particularly limited and can be arbitrarily set. From the viewpoint of seal strength and shelf life of several months, the thickness of each layer is the total thickness of the multilayer film. On the other hand, surface layer (A): 20 to 40% by volume, adhesive layer (B): 5 to 20% by volume, gas barrier layer (C): 5 to 40% by volume, adhesive layer (D): 5 to 20% by volume Surface layer (E): It is preferably 20 to 40% by volume.

The multilayer film of the present embodiment employs a layer configuration of surface layer (A) / adhesive layer (B) / gas barrier layer (C) / adhesive layer (D) / surface layer (E), each of which includes the above-described specific components. In addition, the heat shrinkage stress at 120 ° C. (hereinafter also referred to as “ORS _{120 ° C.} ”) is preferably 1.0 to 3.5 MPa in both the vertical direction (MD direction) and the horizontal direction (TD direction). . In other words, as compared with the conventional case, it is preferable that the tightening force to the packaged object when the packaged object is packaged is increased. The “TD direction” refers to the direction perpendicular to the film flow direction, that is, the width direction of the original roll, and the “MD direction” refers to the film flow direction, that is, the roll direction of the original roll. Point.

When the multilayer film is configured in this way, when the package in which the package is packaged using the multilayer film is subjected to a retort treatment at 120 ° C. for 20 minutes, the multilayer film fits the package and is stored for a long period of time. Even when the shrinkage occurs in the packaged item, the generation of wrinkles derived from the slack of the multilayer film can be effectively suppressed. Considering the suppression of wrinkle generation during long-term storage and the balance of sealing properties, the ORS _{120 ° C. of the} multilayer film is more preferably 1.5 to 3.0 MPa in both the vertical direction and the horizontal direction.

The ORS _{120 ° C. of the} multilayer film can be controlled by the draw ratio at the time of production, the draw temperature, and the heat treatment temperature during or after the draw. Specifically, when the draw ratio is increased or the draw temperature or the heat treatment temperature is lowered. When ORS _{120 ° C.} increases and the draw ratio is lowered, or when the stretching temperature and heat treatment temperature are increased, ORS _{120 ° C.} tends to decrease. In addition, in this specification, ORS ₁₂₀ degreeC of a multilayer film is measured based on ASTMD1504.

  The multilayer film of the present embodiment has a form including at least five layers of surface layer (A) / adhesive layer (B) / gas barrier layer (C) / adhesive layer (D) / surface layer (E) in this order. For example, the mode of use is not particularly limited (here, the symbol “/” in the layer structure means that the layers on both sides thereof are stacked on each other). For example, the surface layer (A) or the surface layer (E) may be subjected to printing or ink jet printing to improve design properties, and two or more multilayer films are bonded to improve the reliability of gas barrier properties. Alternatively, a configuration in which two or more gas barrier layers (C) are stacked may be used. For example, A / B / C / D / E / A / B / C / D / E, or A / B / C / D / E / printing layer / A A layer configuration such as / B / C / D / E is exemplified. By adopting such a layer structure, impact resistance and toughness are further enhanced. Moreover, as a structure which laminated | stacked two or more gas barrier layers (C), layer structures, such as A / B / C / C / D / E and A / B / C / C / C / D / E, are mentioned, for example. Illustrated. By adopting such a layer structure, even if a defect occurs in any of the gas barrier layers (C), the gas barrier property can be ensured by the presence of the other gas barrier layers (C), so the reliability is improved. It is done. Note that the lamination of the multilayer films may be performed using self-adhesion of the surface layer, may be performed using a known adhesive, or may be performed by heat treatment.

(Method for producing multilayer film)
The multilayer film described above 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 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 is shared using a multilayer circular die. After extrusion and solidification with water or warm water, a multilayer annular extrudate (parison / laminate) is obtained. Here, in order to stabilize the parison, it is preferable to provide a cylindrical cooling cylinder having a diameter equal to or smaller than the inner diameter of the parison or 1 to 2 mm below the multilayer circular die. The cooling cylinder used here preferably has a mirror-finished, satin-finished, Teflon (registered trademark), or ceramic-coated surface.

Next, the parison obtained above is heated, air is injected under conditions suitable for imparting orientation, and stretching is performed while forming bubbles, thereby producing a multilayer film. In order to obtain a multilayer film having an ORS of _{120 ° C.} of 1.0 to 3.5 MPa, the stretching temperature is preferably 100 to 130 ° C., more preferably 110 to 130 ° C., and the stretching ratio is preferably an area ratio of 25 to 45 times. More preferably, it is preferably set to 30 to 40 times. In addition, in order to improve stretchability and heat resistance, the parison before stretching may be subjected to crosslinking treatment by irradiating an electron beam (acceleration voltage 150 to 250 kV, irradiation dose 50 to 120 kGy) or the like. Further, during or after stretching, a heat set treatment such as a hot air blowing method, a hot roll method, an indirect heating method using a carbon heater or the like may be performed alone or in combination.

(Cylindrical film molding)
In the cylindrical film molded body, the multilayer film is curved in a cylindrical shape, and both end portions of the multilayer film are overlapped and bonded to each other. Moreover, the cylindrical film molded body has openings at both ends in the axial direction, and can be used as a packaging member capable of packaging the contents (packaged articles) in the cylinder. The tubular film molded body can be obtained by bending the multilayer film into a tubular shape and overlapping the both end portions of the multilayer film, and then joining the both end portions. For example, the multilayer film is curved into a cylindrical shape so that the outer layer (A) constitutes the outer peripheral surface, and the outer layer (E) is overlaid on the surface layer (A) on the envelope, and the surface layer (A The cylindrical film molded body can be obtained by applying heat from the side) and performing heat fusion. This tubular film molded body is, for example, a tubular molded body in which the surface layer (A) constitutes the outer peripheral surface and the surface layer (E) constitutes the inner peripheral surface. The multilayer film is curved in a cylindrical shape so that the outer layer (A) constitutes the outer peripheral surface, and the outer layer (E) and the outer layer (E) are overlapped on the palm and the surface layer (A The cylindrical film molded body can be obtained even when heat sealing is performed by applying heat from the side. Further, it is also possible to obtain a cylindrical film molded body in the same manner by curving into a cylindrical shape so that the surface layer (E) constitutes the outer peripheral surface.

  As the heat sealing method, 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 to seal, and an ultrasonic sealing method can be employed. From the viewpoint of increasing productivity, the hot air sealing method is preferable. The temperature and spray pressure of the hot air in the hot air sealing method may be set as appropriate according to the thickness, rigidity, melting point, etc. of the multilayer film so that the desired heat sealing is performed, but is not particularly limited. From the viewpoint of increasing productivity, the temperature is preferably about 280 to 430 ° C., and the spraying pressure is preferably about 0.2 to 0.6 MPa.

  The sealing strength of the tubular film molded body is preferably 6N or more / 15 mm width from the viewpoint of enhancing the reliability by suppressing peeling during the boil and retort treatment. In addition, for example, in the case of a cylindrical film molded body and a cylindrical package manufactured by superposing the envelope layer with the outer layer (A) as the outer surface, the delamination strength between the adhesive layer (B) and the gas barrier layer (C) (X) is preferably 0.5 to 1.0 N / 15 mm width, and the delamination strength (Y) between the gas barrier layer (C) and the adhesive layer (D) is 0.7 to 1.5 N / 15 mm width. It is preferable that there is an interlayer peel strength (X) <the interlayer peel strength (Y). If comprised in this way, since it will become easy to produce peeling between an adhesion layer (B) and a gas barrier layer (C) at the time of opening, openability improves. In order to make the delamination strength within this range, it can be adjusted by appropriately selecting the above-mentioned acid-modified olefin copolymer used for the adhesive layer (B) and the adhesive layer (D).

(Tubular package)
The cylindrical package of the present embodiment includes the above-described cylindrical film molded body and an article to be packaged filled inside the cylindrical film molded body, and both ends in the axial direction of the cylindrical film molded body are sealed. It has been stopped. You may seal the both ends of a cylindrical film molded object using a sealing member.

(Packaging equipment)
The cylindrical film molded body and the cylindrical package body in which the contents (packaged items) are enclosed are obtained by using a known automatic filling and packaging machine (for example, “ADP (registered trademark)” manufactured by Asahi Kasei Chemicals Corporation). By using it, it can be easily obtained. Hereinafter, the automatic filling and packaging machine 100 that can be suitably used will be described in detail.

  FIG. 1 is a drawing schematically showing a main part structure of an automatic filling and packaging machine 100. FIG. 2 is a drawing for explaining a hot air sealing method. The automatic filling and packaging machine 100 includes a film supply unit 11, a filling unit 21, a tube making unit 31, a hot air sealing unit 41, and a sealing unit 51. In the present embodiment, the tubular body 2 is formed from the belt-shaped multilayer film 1 by the film supply means 11, the tube making means 31, and the hot air sealing means 41, and the tubular film molded body 3 is formed.

  The film supply means 11 includes feed rollers 11a and 11b, feed rollers 12a and 12b, and a drive mechanism (not shown). The film supply means 11 forms a belt shape from the original roll according to the drive of the drive mechanism and the feed rollers 12a and 12b (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 21 has a hollow cylindrical filling nozzle 22, and a feed pump 23 that supplies an article to be packed into the filling nozzle 22 is connected to the upper end of the filling nozzle 21. The filling means 21 supplies the article to be packaged into the filling nozzle 22 according to the drive of the feed pump 23.

  The tube making means 31 has a tube making folder 32 formed by winding a metal piece of a predetermined shape into a substantially spiral shape. The tube making folder 32 is formed so that the inner peripheral diameter thereof is larger than the outer peripheral diameter of the filling nozzle 22 and is arranged substantially concentrically with the filling nozzle 22. Therefore, the outer peripheral wall of the filling nozzle 22 and the inner peripheral wall of the tube making folder 32 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 32, and follows the spiral structure, when passing the inside of the cylinder making folder 32. It becomes a cylindrical body 2 which is curved in a cylindrical shape and whose both end edges 1a and 1b are overlapped (see FIG. 2), and is transferred downward from the bottom opening of the cylindrical folder 32 in FIG.

  The hot air sealing means 41 has a hot air applying nozzle 42 and a pressure adjusting mechanism and a temperature adjusting mechanism (not shown), and is arranged at a position separated from the outer peripheral wall of the filling nozzle 22 by a predetermined distance below the tube making folder 32. Has been. Hot air is blown from the nozzle opening 42a of the hot air application nozzle 42 to the overlapping portion 2a of the tubular body 2 that has passed through the tube-making folder 32 (the portion where the both end edges 1a and 1b of the multilayer film 1 are overlapped). Hot air sealing is performed by fusing the part 2a. 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 property, the hot air applying nozzle 42 is a position where hot air is blown from the vertical direction to the overlapping portion 2a of the cylindrical body 2 (to a tangential contact in the cross section of the overlapping portion 2a), In other words, it is preferably disposed at a position where hot air can be blown from a direction substantially perpendicular to the tangent line of the overlapping portion 2a in the cross section of the cylindrical body 2.

  When the overlapping portion 2a is sealed with hot air, a substantially cylindrical tubular film molded body 3 is formed. The cylindrical film molded body 3 is filled with the article to be packaged from the filling nozzle 22 described above, and thus the cylindrical film molded body 3 filled with the article to be packaged is sandwiched between the feed rollers 12a and 12b. 1 is moved downward.

  The sealing unit 51 includes squeezing rollers 52 a and 52 b and a sealing mechanism 53. The sealing means 51 is configured to press the cylindrical film molded body 3 filled with an object to be packaged from the outside at predetermined intervals by the squeezing rollers 52a and 52b, and then to dissipate the object to be packaged at the pressed portion. The mechanism 53 focuses and seals the multilayer film 1 in the pressed area. That is, the sealing means 51 seals both end openings corresponding to the upper and lower bases of the tubular film molded body 3. The sealing process in the sealing mechanism 53 includes a method of applying ultrasonic waves, high frequency or heat to the converging part of the multilayer film 1 and fusing it, or a synthetic resin or metal wire or the like on the converging part of the multilayer film 1. 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 3 are sealed, whereby the tubular packaging body 4 is manufactured. In addition, you may divide | segment the cylindrical packaging body 4 by which the both ends were sealed into each cylindrical packaging body 4 simultaneously with a sealing process, or in the subsequent cutting process. Moreover, after sealing the both ends of the cylindrical film molding 3, you may obtain the cylindrical packaging body 4 by carrying out a heat sterilization process (boil and retort process).

  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.

  Such multilayer films are used for bag-shaped packaging materials, pillow packaging materials, tray packaging materials, top seal lid materials, frozen packaging materials, casing packaging materials, etc., and also for packaging materials for vacuum packaging and gas replacement packaging. It can be suitably used.

  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) Dynamic friction coefficient The dynamic friction coefficient of the multilayer film at 23 ° C was measured in accordance with JIS K7125. In measurement of this dynamic friction coefficient, it measured about the vertical direction (MD direction) of surface layers (A layer and E layer) of a multilayer film, and used the average value of n = 5 as a dynamic friction coefficient.

(2) Retort suitability About 300 packages, a retort treatment was performed at 120 ° C. for 20 minutes under the condition of a heated can pressure gauge pressure of 0.25 MPa, and the number of punctures that occurred was counted. The evaluation was made according to the following criteria.
○: The number of broken bags (punk) is 0 ×: The number of broken bags (punk) is 1 or more

(3) Seal stability The cylindrical film molded body 10m was measured with a caliper every 1 m (unit: mm, rounded to the second decimal place). The difference between the maximum value and the minimum value of the measured values was regarded as the variation (mm) of the seal line width, and evaluated according to the following criteria.
A: Variation in seal line width is less than 1.0 mm B: Variation in seal line width is 1.0 mm or more and less than 2.0 mm X: Variation in seal line width is 2.0 mm or more

(4) Meat adherence amount 120 degreeC and the retort-treated packaging film for 20 minutes were peeled off, and the resistance when the film was peeled off and the amount of meat attached to the film were evaluated according to the following criteria.
○: The film peels off with a moderate resistance, and the amount of meat attached is slight.
X: There is almost no sense of resistance, the film peels off, and there is almost no meat adhesion. Alternatively, the film is peeled off with a considerable sense of resistance, and meat is attached to the whole.

(5) Preservability Twenty packages that were retorted at 120 ° C. for 20 minutes were stored for 3 months under a temperature condition of 28 ° C., and the water separation state of the package was visually evaluated according to the following criteria.
○: No water separation is observed.
X: Water separation is observed.

(6) Crystal melting temperature (melting point)
The melting point was measured using a Pyris Diamond DSC manufactured by Perkin Elmer. First, the sample was heated from 10 ° C. to 300 ° C. under the condition of 10 ° C./min and held at 300 ° C. for 1 minute. Next, the sample was cooled to 10 ° C. under the condition of 10 ° C./min, and held at 10 ° C. for 1 minute. Furthermore, the peak value of the crystal melting curve when the sample was heated again at 10 ° C./min was read as the melting point.

(7) Boil suitability 300 packages were boiled at 90 ° C. for 60 minutes under atmospheric pressure, and the number of broken bags was counted and evaluated according to the following criteria. did.
○: The number of broken bags (punk) is 0 ×: The number of broken bags (punk) is 1 or more

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

[Example 1]
First, it melt-coextruded using the cyclic | annular 5-layer die with the layer structure shown in Table 2, Then, it solidified with the cold water of about 15 degreeC, and produced the tube-shaped unstretched original fabric of about 1100 micrometers in total thickness. Next, the unstretched original fabric was biaxially stretched at a stretching temperature of about 120 ° C. and a stretching ratio of about 30 times, which was about 5 times in the machine direction and about 6 times in the transverse direction by an inflation method, and then heated at 90 ° C. A multilayer film having a final thickness of about 40 μm was obtained by heat treatment with a roll. 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.

  Next, using a hot air sealing type automatic filling and packaging machine ("ADP (registered trademark)" manufactured by Asahi Kasei Chemicals Corporation), the outer layer (A) of the multilayer film of Example 1 is configured to constitute the outer peripheral surface. The tube was bent into a cylindrical shape through a tube making folder, and the surface layer (E) was superposed on the surface layer (A). 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.

[Examples 2, 5, 6, 7]
The resin shown in Table 2 was used in the same manner as in Example 1 except for the resin composition ratio to obtain a tubular film molded body and a tubular package. Table 2 shows the evaluation results of various performance evaluations.

[Example 3]
The resin shown in Table 2 was biaxially stretched at a stretching ratio of about 40 times, which was about 6 times in the vertical direction and about 6.7 times in the horizontal direction, and then heat treated with a heating roll at 90 ° C. A cylindrical film molded body and a cylindrical package were obtained in the same manner as in Example 1 except that the thickness was about 30 μm. Table 2 shows the evaluation results of various performance evaluations.

[Example 4]
The resin shown in Table 2 was biaxially stretched at a stretch ratio of about 25 times, about 5 times in the vertical direction and about 5 times in the horizontal direction, and then heat-treated with a heating roll at 90 ° C. to obtain a final thickness of about A cylindrical film molded body and a cylindrical package were obtained in the same manner as in Example 1 except that the thickness was 50 μm. Table 2 shows the evaluation results of various performance evaluations.

[Comparative Examples 1 and 2]
The resin shown in Table 3 was used in the same manner as in Example 1 except for the resin composition ratio to obtain a tubular film molded body and a tubular package. Table 3 shows the evaluation results of various performance evaluations.

[Comparative Example 3]
By biaxially stretching the resin shown in Table 3 at a stretching ratio of about 22 times, which is about 4.7 times in the vertical direction and about 4.7 times in the horizontal direction, and then heat-treated with a heating roll at 90 ° C. A cylindrical film molded body and a cylindrical package were obtained in the same manner as in Example 1 except that the final thickness was about 55 μm. Table 3 shows the evaluation results of various performance evaluations.

[Comparative Example 4]
The resin shown in Table 3 was biaxially stretched at a stretch ratio of about 49 times, about 7 times in the vertical direction and about 7 times in the horizontal direction, and then heat-treated with a heating roll at 100 ° C. to obtain a final thickness of about The tubular film molded body and the tubular packaging body were prepared in the same manner as in Example 1 except that the surface layer (E) of the obtained multilayer film was subjected to corona treatment so that the wetting tension was 38 mN / m. Obtained. Table 3 shows the evaluation results of various performance evaluations.

  The multilayer film of the present invention, and a cylindrical film molded body and a cylindrical package using the multilayer film, when used as a cylindrical package without subjecting the multilayer film to corona treatment, are stored for a long period of about several months. While peeling off the film while suppressing the occurrence of water separation phenomenon later, adhesion of the package to the film is slight while having an appropriate resistance, and excellent in the running property of the film during continuous high-speed filling, Stable sealability is expressed, the reliability of the seal part is excellent, it looks good and has a beautiful appearance, and can improve the product value, so it can be used widely and effectively in food and other various packaging applications. It can be used particularly effectively in applications that require high temperature heat sterilization such as boil and retort treatment.

  DESCRIPTION OF SYMBOLS 1 ... Multilayer film, 1a, 1b ... Both ends edge, 2 ... Cylindrical body, 2a ... Overlapping part, 3 ... Cylindrical film molded object, 4 ... Cylindrical package, 11 ... Film supply means, 11a, 11b ... Feed Roller, 12a, 12b ... feed roller, 21 ... filling means, 22 ... filling nozzle, 23 ... feed pump, 31 ... tube making means, 32 ... tube making folder, 41 ... hot air sealing means, 42 ... hot air applying nozzle, 42a ... Nozzle opening, 51 ... sealing means, 52a, 52b ... squeezing roller, 53 ... sealing mechanism, 100 ... automatic filling and packaging machine.

Claims (3)

Surface layer (A), adhesive layer (B) containing an acid-modified olefin copolymer, gas barrier layer (C) containing an aromatic polyamide polymer, and an adhesive layer (D) containing an acid-modified olefin copolymer ) And the surface layer (E) are laminated in this order,
In the surface layer (A), the content of the olefin polymer is 60% by mass or more, an acid-modified olefin copolymer, an ethylene-aliphatic unsaturated carboxylic acid copolymer, and ethylene-aliphatic unsaturation. The content of at least one selected from a carboxylic acid ester copolymer and an acid-modified product thereof is 40% by mass or less,
In the surface layer (E), the content of the olefin polymer is 60 to 99% by mass, the acid-modified olefin copolymer, the ethylene-aliphatic unsaturated carboxylic acid copolymer, and the ethylene-aliphatic non-aliphatic copolymer. The content of at least one selected from a saturated carboxylic acid ester copolymer and an acid-modified product thereof is 1 to 40% by mass,
Dynamic friction coefficient between the surface layer (A) and surface layer (E) which is measured in accordance with JIS K7125 is Ri der 0.10 to 0.30,
The olefin polymer of the surface layer (A) is a propylene polymer,
Wherein said acid-modified olefinic copolymer adhesive layer (B), Ru said acid-modified olefinic copolymer and the acid-modified propylene-based copolymer der of the adhesive layer (D), a multilayer film. The multilayer film according to claim 1 is curved in a cylindrical shape,
A tubular film molded body in which both end portions of the multilayer film overlap and are joined to each other. A tubular film molded body according to claim 2 , and a packaged article filled in the tubular film molded body,
A cylindrical package in which both ends of the cylindrical film molded body are sealed.

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