JP7308640B2 - LAMINATED BODY AND FLUID PACKAGING BAG USING THE SAME - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminate having an excellent balance of heat resistance and impact resistance, and a fluid packaging bag using the laminate.

In some cases, packaging bags containing medical products and foods are sterilized at a high temperature of about 100 to 140° C. after being filled and sealed in order to enable long-term storage. As the packaging bag, for example, a laminated body (laminated film) formed by laminating a plurality of resin films in a bag shape is used. The packaging bag is required to have enough heat resistance to withstand high-temperature and high-pressure sterilization, and strength (shock resistance) that does not break even if dropped during distribution.

Patent Literature 1 discloses a laminated material obtained by laminating an inner surface material on a surface material made of a plastic film having high heat resistance and moisture resistance using a heat-resistant adhesive. The inner surface material is made by laminating three or more layers of polyethylene or ethylene/α-olefin copolymer films, and the density of the plastic constituting both outermost layers is 0.939 or more, and the intermediate It is disclosed that the density of the plastic making up the layers is between 0.910 and 0.925. Furthermore, by using high-density plastic for both outermost layers, this laminated material can prevent softening of the inner surface material due to heat during retort sterilization. It is explained that the impact resistance and cold resistance of can be improved.

Patent Document 2 describes a propylene polymer component (A), a propylene/α-olefin random copolymer component (B), and a random copolymer component (C) of ethylene and an α-olefin having 4 or more carbon atoms. discloses a heat-fusible laminated film obtained by laminating a substrate layer on one side of a heat-fusible film obtained from a specific propylene polymer composition. The heat-fusible laminated film has high rigidity and low-temperature impact resistance, and is therefore useful as a packaging film for items requiring heat and sterilization, such as retort food. It is

In Patent Document 3, at least one outer layer which is the same or different and which is formed from a polyethylene-based resin composition (A) having an MFR of 0.5 to 10 g/10 min and a density of 940 to 960 kg/m ³ , A resin laminate formed from at least one same or different intermediate layer formed from a polyethylene resin composition (B) having an MFR of 0.5 to 10 g/10 min and a density of 925 to 935 kg/m ³ A film is disclosed. It is also described that this resin laminated film has excellent impact strength, and even when subjected to retort treatment at temperatures exceeding 121° C., the transparency of the film is less reduced and the heat-resistant adhesiveness is excellent.

JP-A-2-095849 JP-A-2003-183462 JP 2005-059243 A

The present inventors focused on the problem that it is difficult to achieve both heat resistance and impact resistance in a laminate composed of a plurality of layers composed of resin components. Specifically, for example, there is a tendency that if the heat resistance of the laminate is improved, the impact resistance tends to be lowered, and it was thought that there is room for further improvement in terms of the balance between these two properties.

That is, an object of the present invention is to provide a laminate having an excellent balance of heat resistance and impact resistance, and a fluid packaging bag using the same.

The present inventors have made intensive studies to achieve the above object, and found that setting the physical properties of each layer of the laminate within an appropriate range is very effective in terms of the balance between heat resistance and impact resistance. After discovering a certain thing, the present invention was completed. That is, the present invention is specified by the following matters.

[1] A laminate having at least an outer layer (A), an intermediate layer (B) and an inner layer (C) made of a resin component,
The resin component constituting the outer layer (A) has a melt flow rate (MFR) of 0.1 to 20 g/10 minutes measured under a load of 2.16 kg at 190° C., and a density of 900 to 960 kg/m ³ . can be,
The melt flow rate (MFR) of the resin component constituting the intermediate layer (B) measured at 190° C. and a load of 2.16 kg is 0.1 to 20 g/10 minutes, and is obtained from the DSC curve of DSC measurement 110 ° C. or higher melting heat ratio (Hh / Ht), which is the ratio of the heat of melting (Hh) obtained from the DSC curve at 110 ° C. or higher to the total heat of melting (Ht), is 11 to 80%;
The resin component constituting the inner layer (C) has a melt flow rate (MFR) of 0.1 to 20 g/10 minutes measured under a load of 2.16 kg at 190° C. and a density of 920 to 960 kg/m ³ . A laminate.

[2] The laminate according to [1], further comprising a substrate layer (D) outside the outer layer (A).

[3] Described in [1] or [2], wherein the resin constituting the outer layer (A), the intermediate layer (B) and the inner layer (C) contains a copolymer of ethylene and an α-olefin having 3 or more carbon atoms. laminate.

[4] The laminate according to any one of [1] to [3], which has a thickness of 3 to 300 μm.

[5] The laminate according to any one of [1] to [4], which is a laminate for a fluid packaging material.

[6] A fluid packaging bag having the laminate according to any one of [1] to [5].

According to the present invention, it is possible to provide a laminate having an excellent balance between heat resistance and impact resistance, and a fluid packaging bag using the laminate.

<Outer layer (A)>
In the present invention, the outer layer (A) is a layer composed of a resin component, and is a layer located on the opposite side of the intermediate layer (B) from the inner layer (C). The outer layer (A) is particularly preferably a laminate layer.

The melt flow rate (MFR) of the resin component constituting the outer layer (A) measured at 190° C. under a load of 2.16 kg is 0.1 to 20 g/10 min, preferably 0.5 to 12 g/10 min. More preferably, it is 1 to 12 g/10 minutes. It is preferred that the MFR is not too low from the viewpoint of extrusion moldability, and that it is not too high is preferred from the viewpoint of impact resistance.

The density of the resin component constituting the outer layer (A) is 900-960 kg/m ³ , preferably 905-955 kg/m ³ , more preferably 910-950 kg/m ³ . It is preferable that the density is not too low from the viewpoint of heat resistance, and that the density is not too high is preferable from the viewpoint of impact resistance.

The resin component constituting the outer layer (A) may consist of only one kind of resin, or may contain two or more kinds of resins. Although the type of resin is not particularly limited, an olefin polymer is preferred, and an ethylene polymer is more preferred. The olefin-based polymer (such as an ethylene-based polymer) may be a homopolymer or a copolymer. Particularly preferred is a copolymer of ethylene and an α-olefin having 3 or more carbon atoms (ethylene/α-olefin copolymer). Specific examples of the α-olefin in the ethylene/α-olefin copolymer include propylene, butene, 1-octene and 1-hexene. Among them, 1-hexene and 1-octene are preferred, and 1-hexene is more preferred.

The resin component constituting the outer layer (A) preferably contains the ethylene/α-olefin copolymer described above. The ethylene/α-olefin copolymer may be used alone or in combination of two or more.

The method for producing the ethylene/α-olefin copolymer is not particularly limited, and it can be obtained, for example, by polymerization using an olefin polymerization catalyst such as a metallocene-based catalyst, a titanium-based catalyst, a chromium-based catalyst, or a phenoxyimine-based catalyst. In particular, an ethylene/α-olefin copolymer obtained by polymerization using a metallocene catalyst is preferred. The metallocene-based catalyst is usually a metallocene catalyst component (a) consisting of a transition metal compound of group IVB of the periodic table having at least one ligand having a cyclopentadienyl skeleton, and an organoaluminum oxy compound catalyst component (b). , a particulate carrier (c), and optionally an organoaluminum compound catalyst component (d) and an ionized ionic compound catalyst component (e).

If necessary, additives may be added to the resin component constituting the outer layer (A). Specific examples of additives include antiblocking agents, antifogging agents, antistatic agents, antioxidants, weather stabilizers, heat stabilizers, and lubricants.

The thickness of the outer layer (A) is generally 1-150 μm, preferably 1-100 μm, more preferably 3-100 μm.

<Intermediate layer (B)>
In the present invention, the intermediate layer (B) is a layer composed of a resin component and positioned between the outer layer (A) and the inner layer (C).

The melt flow rate (MFR) of the resin component constituting the intermediate layer (B) measured at 190° C. under a load of 2.16 kg is 0.1 to 20 g/10 minutes, preferably 0.5 to 12 g/10 minutes. , more preferably 1 to 12 g/10 min. It is preferred that the MFR is not too low from the viewpoint of extrusion moldability, and that it is not too high is preferred from the viewpoint of impact resistance.

Heat of fusion at 110°C or higher, which is the ratio of the heat of fusion (Hh) obtained from the DSC curve at 110°C or higher to the total heat of fusion (Ht) obtained from the DSC curve of the DSC measurement of the resin component constituting the intermediate layer (B) The ratio (Hh/Ht) is 11-80%, preferably 15-75%, more preferably 20-70%. It is preferable from the viewpoint of heat resistance that Hh/Ht is not too low, and it is preferable from the viewpoint of impact resistance that Hh/Ht is not too high. A specific method for calculating Hh/Ht will be described in the Examples section below.

The resin component constituting the intermediate layer (B) may consist of only one type of resin, or may contain two or more types of resin. Although the type of resin is not particularly limited, an olefin polymer is preferred, and an ethylene polymer is more preferred. The olefin-based polymer (such as an ethylene-based polymer) may be a homopolymer or a copolymer. Particularly preferred is a copolymer of ethylene and an α-olefin having 3 or more carbon atoms (ethylene/α-olefin copolymer). Specific examples of the α-olefin in the ethylene/α-olefin copolymer include propylene, butene, 1-octene and 1-hexene. Among them, 1-hexene and 1-octene are preferred, and 1-hexene is more preferred.

The resin component constituting the intermediate layer (B) preferably contains the ethylene/α-olefin copolymer described above. The ethylene/α-olefin copolymer may be used alone or in combination of two or more. In particular, it is preferable to use two or more polymers in combination from the viewpoint of adjusting physical properties such as Hh/Ht, MFR and density. For example, by mixing a polymer having a relatively high melting point with a polymer having a general melting point, the Hh/Ht of the intermediate layer (B) can be easily increased. When two or more polymers are used in combination, the polymers may be mixed using a mixing device such as a Banbury mixer, Henschel mixer, V-type blender, extruder, or the like.

The method for producing the ethylene/α-olefin copolymer is not particularly limited. A specific example of the manufacturing method thereof is the same as that described above for the outer layer (A).

If necessary, additives may be added to the resin component constituting the intermediate layer (B). Specific Examples of Additives Specific examples are the same as those described above for the outer layer (A).

The thickness of the intermediate layer (B) is generally 1-150 μm, preferably 1-100 μm, more preferably 3-100 μm.

<Inner layer (C)>
In the present invention, the inner layer (C) is a layer composed of a resin component, and is a layer located on the opposite side of the intermediate layer (B) from the outer layer (A). The inner layer (C) is particularly preferably a heat-sealable layer.

The melt flow rate (MFR) of the resin component constituting the inner layer (C) measured at 190° C. under a load of 2.16 kg is 0.1 to 20 g/10 min, preferably 0.5 to 12 g/10 min. More preferably, it is 1 to 12 g/10 minutes. It is preferred that the MFR is not too low from the viewpoint of extrusion moldability, and that it is not too high is preferred from the viewpoint of impact resistance.

The density of the resin component constituting the inner layer (C) is 920-960 kg/m ³ , preferably 920-955 kg/m ³ , more preferably 920-950 kg/m ³ . Also, these densities may be 925 kg/m ³ or more. That is, it may be within each range of 925 to 960 kg/m ³ , 925 to 955 kg/m ³ and 925 to 950 kg/m ³ . It is preferable that the density is not too low from the viewpoint of heat resistance, and that the density is not too high is preferable from the viewpoint of impact resistance.

The resin component constituting the inner layer (C) may consist of only one kind of resin, or may contain two or more kinds of resins. Although the type of resin is not particularly limited, an olefin polymer is preferred, and an ethylene polymer is more preferred. The olefin-based polymer (such as an ethylene-based polymer) may be a homopolymer or a copolymer. Particularly preferred is a copolymer of ethylene and an α-olefin having 3 or more carbon atoms (ethylene/α-olefin copolymer). Specific examples of the α-olefin in the ethylene/α-olefin copolymer include propylene, butene, 1-octene and 1-hexene. Among them, 1-hexene and 1-octene are preferred, and 1-hexene is more preferred.

The resin component constituting the inner layer (C) preferably contains the ethylene/α-olefin copolymer described above. The ethylene/α-olefin copolymer may be used alone or in combination of two or more.

The method for producing the ethylene/α-olefin copolymer is not particularly limited. A specific example of the manufacturing method thereof is the same as that described above for the outer layer (A).

If necessary, additives may be added to the resin component constituting the inner layer (C). Specific Examples of Additives Specific examples are the same as those described above for the outer layer (A).

The thickness of the inner layer (C) is generally 1-150 μm, preferably 1-100 μm, more preferably 3-100 μm.

<Base material layer (D)>
The laminate of the present invention may further have a substrate layer (D) outside the outer layer (A).

The type of material that constitutes the base material layer (D) is not particularly limited. For example, various materials capable of exhibiting a function as a substrate can be used, such as thermoplastic resins or stretched products thereof, inorganic oxide vapor deposition films, metal vapor deposition films, ceramic vapor deposition films, metal foils, paper, and non-woven fabrics. When using a resin, for example, polyamide resin such as nylon 11 and nylon 12, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, polyolefin resin such as polyethylene resin and polypropylene resin, polystyrene resin, polyvinylidene chloride resin, and polycarbonate resin. , ethylene-vinyl acetate copolymer saponified products, and acrylic resins can be used. Furthermore, as the substrate layer (D), for example, a two-layer film obtained by dry-laminating a polyester film and a ceramic-deposited polyester film, or a three-layer film obtained by dry-laminating a polyester film and an aluminum foil and further dry-laminating a polyester film on the aluminum foil surface. Film can also be used.

The thickness of the substrate layer (D) is generally 1-100 μm, preferably 2-90 μm, more preferably 3-60 μm.

<Laminate>
The laminate of the present invention includes the outer layer (A) [e.g. laminate layer], the intermediate layer (B), the inner layer (C) [e.g. heat-sealable layer] described above, and, if necessary, the base layer (D). It is a laminate having Moreover, you may further have a layer other than each of these layers. For example, it may have a laminate layer or an adhesive layer other than these layers.

The layer thickness ratio [(A)/(B)/(C)] of the outer layer (A), the intermediate layer (B) and the inner layer (C) is preferably 1 when the thickness of the outer layer (A) is 1. /0.1-20/0.1-20, more preferably 1/0.2-10/0.2-10.

The thickness of the entire laminate is usually 3-300 μm, preferably 5-200 μm.

The method for producing the laminate of the present invention is not particularly limited. For example, a laminate can be obtained by separately or simultaneously melt extruding the resin components constituting each layer.

The laminate of the present invention has an improved balance between heat resistance and impact resistance by setting the physical properties of each layer within an appropriate range. For example, an appropriate balance can be achieved by adjusting the melting heat ratio (Hh/Ht) at 110° C. or higher of the resin component constituting the intermediate layer (B) to an appropriate value. It is also effective to make the density of the resin component constituting the intermediate layer (B) relatively low.

Since the laminate of the present invention has an excellent balance of heat resistance and impact resistance, it is less prone to defects even when exposed to high temperatures and is less likely to break when subjected to impact. Therefore, it is useful for various applications requiring heat resistance and impact resistance, such as food and medical fields. Specifically, it can be suitably used as a packaging material for fluid or solid packaged items that require heating and sterilization treatment, such as retort food, pharmaceuticals, medical instruments, and pet food. Among others, it is very useful in applications as materials for packaging fluids (fluid packaging materials).

<Fluid packaging bag>
A fluid packaging bag of the present invention is a fluid packaging bag having the laminate described above. In the present invention, "fluid" means both liquid and viscous. Specific examples of the fluid include liquid or viscous foods such as retort pouch foods and beverages, and liquid or viscous medical products such as pharmaceuticals.

In the fluid packaging bag of the present invention, the laminate of the present invention may be used as part or all of the material for packaging the fluid, and members other than the laminate of the present invention may be included. do not have.

In the fluid packaging bag of the present invention, the laminate is arranged so that the inner layer (C) is inside the bag. For example, the inner layer (C) side of two laminates can be superimposed and two-sidedly, three-sidedly or four-sidedly sealed with a heat sealing machine to form a bag. Although the shape of the bag is not particularly limited, it is usually rectangular.

The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples.

In Examples and Comparative Examples, the following resins a to g were used as resin components.
"a": Ethylene/1-hexene copolymer (manufactured by Prime Polymer Co., Ltd., Evolue (registered trademark) SP4030, MFR (190°C, 2.16 kg) = 4.0 g/10 min, density = 938 kg/m ³ )
"b": Ethylene/1-hexene copolymer (manufactured by Prime Polymer Co., Ltd., Evolue (registered trademark) SP0540, MFR (190°C, 2.16 kg) = 3.8 g/10 min, density = 903 kg/m ³ )
"c": Ethylene/1-hexene copolymer (manufactured by Prime Polymer Co., Ltd., Evolue (registered trademark) SP4530, MFR (190°C, 2.16 kg) = 2.9 g/10 min, density = 938 kg/m ³ )
"d": Ethylene/1-hexene copolymer (manufactured by Prime Polymer Co., Ltd., Evolue (registered trademark) SP1540, MFR (190°C, 2.16 kg) = 3.8 g/10 min, density = 913 kg/m ³ )
"e": Ethylene/1-hexene copolymer (manufactured by Prime Polymer Co., Ltd., Evolue (registered trademark) SP2040, MFR (190°C, 2.16 kg) = 3.8 g/10 min, density = 918 kg/m ³ )
"g": Ethylene/1-hexene copolymer (manufactured by Prime Polymer Co., Ltd., Evolue (registered trademark) SP0510, MFR (190°C, 2.16 kg) = 1.2 g/10 min, density = 903 kg/m ³ )

[Examples 1 to 8 and Comparative Examples 1 to 3]
First, a laminate (laminated film) composed of an outer layer (A), an intermediate layer (B) and an inner layer (C) composed of resins shown in Tables 1 to 3 was produced. The thickness of the outer layer (A) was 16 μm, the thickness of the intermediate layer (B) was 48 μm, and the thickness of the inner layer (C) was 16 μm. However, in Comparative Examples 1 and 2, a single-layer film consisting of only the outer layer (A) was produced.

Next, on the outer layer (A) side of the laminated films of Examples 1 to 8 and Comparative Examples 3 and 4 and the single layer film of Comparative Example 1, a substrate made of biaxially oriented polyester (OPET) as a substrate layer (D) (Thickness: 16 μm) was laminated using an anchor coating agent to obtain a dry lamination laminate.

The following tests were conducted on the dry lamination laminate obtained as described above. Results are shown in Tables 2 and 3.

<Melt flow rate (MFR)>
The melt flow rate (MFR) of the resin component constituting each layer was measured under conditions of 190° C. and a load of 2.16 kg according to JIS K7210-1.

<Density>
The density of the resin component constituting each layer was measured according to JIS K7112 by the density gradient tube method after heat-treating the strand obtained during MFR measurement at 100° C. for 1 hour and allowing it to stand at room temperature for 1 hour.

<Melting heat ratio>
The heat of fusion ratio of the resin components constituting the intermediate layer (B) is determined from the total heat of fusion (Ht) obtained from the DSC curve of DSC measurement and the heat of fusion (Hh) obtained from the DSC curve at 110° C. or higher. The heat of fusion ratio (Hh/Ht) above 110°C, which is the ratio, was calculated.

<Heat resistant temperature>
The temperature at which wrinkles and fusion do not occur when the dry lamination laminate is sterilized at an arbitrary temperature for 5 minutes is taken as the heat resistant temperature.

<Film strength>
(1) Pinhole resistance (number of pinholes)
A test piece having a size of 208 mm×205 mm was cut out from the laminated film (or single layer film). Then, using a Gelbo Flex Tester manufactured by Tester Sangyo Co., Ltd., a bending test was performed 3000 times in each atmosphere at 23° C. under the conditions of a bending angle of 440°, a stroke of 152 mm, and a test speed of 42 times/minute. The number of pinholes generated at that time was measured by a pinhole tester manufactured by Nikka Densai Co., Ltd.

(2) Dart impact According to ASTM D 1709 A method, a test piece cut out from a laminated film (or single layer film) is clamped with an air clamp method, a hemispherical dart is dropped from a fixed height position, and the test piece The dart impact, which is the load (g) at 50% failure, was read from the graph. The number of drops for one level was set to 10 times.

As is clear from Tables 1 and 2, the laminates of Examples 1 to 8 had an excellent balance of heat resistance and impact resistance.

The film of Comparative Example 1 was a single-layer film composed of resin e, and was inferior in heat resistance.

The laminate of Comparative Example 2 was a laminate film in which all layers were composed of resin a having an excessively high heat of fusion ratio (Hh/Ht) of 110° C. or higher, and was inferior in impact resistance (dirt impact).

The laminate of Comparative Example 3 was a laminate film in which the intermediate layer (B) was composed of the resin b whose heat of fusion ratio (Hh/Ht) was too low at 110° C. or higher, and was inferior in heat resistance.

The laminate of the present invention can be suitably used as a packaging material for fluid or solid packaged items that require heating and sterilization treatment, such as retort food, pharmaceuticals, medical instruments, and pet food. Among others, it is very useful in applications as materials for packaging fluids (fluid packaging materials).

Claims (6)

A laminate having at least an outer layer (A), an intermediate layer (B) and an inner layer (C) made of a resin component,
The resin component constituting the outer layer (A) has a melt flow rate (MFR) of 0.1 to 20 g/10 minutes measured under a load of 2.16 kg at 190° C., and a density of 900 to 960 kg/m ³ . can be,
The melt flow rate (MFR) of the resin component constituting the intermediate layer (B) measured at 190 ° C. and a load of 2.16 kg is 3.5 to 20 g / 10 minutes, and is obtained from the DSC curve of DSC measurement 110 ° C. or higher melting heat ratio (Hh / Ht), which is the ratio of the heat of melting (Hh) obtained from the DSC curve at 110 ° C. or higher to the total heat of melting (Ht), is 11 to 80%;
The resin component constituting the inner layer (C) has a melt flow rate (MFR) of 0.1 to 20 g/10 minutes measured under a load of 2.16 kg at 190° C. and a density of 920 to 960 kg/m ³ . A laminate. 2. The laminate according to claim 1, further comprising a substrate layer (D) outside the outer layer (A). 3. The laminate according to claim 1, wherein the resin constituting the outer layer (A), the intermediate layer (B) and the inner layer (C) contains a copolymer of ethylene and an α-olefin having 3 or more carbon atoms. The laminate according to any one of claims 1 to 3, which has a thickness of 3 to 300 µm. The laminate according to any one of claims 1 to 4, which is a laminate for a fluid packaging material. A fluid packaging bag comprising the laminate according to any one of claims 1 to 5.