JP2019142021A - Laminate for packaging bag, and packaging bag - Google Patents

Abstract

To provide a laminate for a packaging bag hardly generating a pinhole, even when a stress such as torsion, drop impact or friction is applied thereto.SOLUTION: In a laminate 10 for a packaging bag, which is a laminate having a substrate layer 1 and a sealant layer 2, the substrate layer 1 contains a nylon film or a polyester film, and in the sealant layer 2, a tensile modulus based on JIS K 7127 is 350 MPa or less, and a tear strength based on JIS K 7128 is 6.0 N or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminated body for packaging bags and a packaging bag.

  As a constituent material of a packaging bag for enclosing and transporting liquid articles such as foods, paints, cosmetics, and pharmaceuticals, a packaging bag laminate composed of a laminate of a plurality of films is known.

  For example, Patent Document 1 describes a laminate material in which a biaxially stretched polypropylene film layer, an oxygen barrier layer, and a sealant layer are laminated in this order, and this laminate material is 2 in a medical infusion pack. It is described as being suitable as a next packaging material.

  Patent Document 2 describes a polyethylene-based resin composition composed of linear low-density polyethylene and high-pressure low-density polyethylene, and a bag-in-box interior container formed from this resin composition.

  Patent Document 3 describes a method of manufacturing a packaging bag containing contents using a vertical bag making and filling machine. In the method of Patent Document 3, both edges of a long film are thermally welded to form a cylindrical film having a vertical seal portion formed thereby, and the inner surfaces facing each other are connected to each other. In the width direction, a process of heat-welding leaving a part so as to form an opening, a process of charging a package (contents) into the cylindrical film from the opening, and an opening after charging of the package And heat-welding the inner surfaces of the cylindrical film facing each other in the width direction.

JP 2006-7509 A JP 11-166081 A JP 2002-234504 A

  It is difficult for pinholes to occur when stress such as twisting, dropping impact, friction on the bent part is applied to the packaging bag for packaging liquid articles and the laminate material constituting the packaging bag. Desired. The reason is as follows.

  When manufacturing a packaging bag containing contents from a laminate for a packaging bag, the method described in Patent Document 3 is specifically performed as follows, for example. The laminated body for packaging bags is formed into a long film and wound into a roll. For example, the wound laminate material is unwound in the horizontal direction and then twisted by 90 ° to change the direction to the vertical direction, and is supplied from above to the vertical bag making and filling machine. At this time, pinholes may be generated due to stress that twists the laminate material.

  The laminated body for packaging bags supplied to the bag making and filling machine is formed into a cylindrical body having an opening by sealing one end or both ends of the side in the length direction (for example, heat-sealing), and further on the film end side After the opening is sealed and formed into a bag shape, for example, a liquid article (package) is injected from the opening. After injection of the liquid article, the opening of the cylindrical body is sealed, and further cut by the seal portion to form a packaging bag containing contents. This package bag with contents falls to the floor after being cut. At the time of the fall, a drop impact is applied to the packaging bag, and a pinhole may be generated due to the stress.

  The obtained content-containing packaging bags are packed several times in, for example, cardboard boxes, and transported to a consumption area by, for example, a railroad, a truck, an aircraft, or the like. Due to vibration during transportation, the packaging bag may be rubbed between another packaging bag packed adjacently or the wall of the packaging cardboard box, and a pinhole may be generated due to the stress. In particular, the liquid article as the contents may be shaken by vibration during transportation to push up a part of the laminate material from the inside of the packaging bag, and the laminate material may be wrinkled or creased. When the bent part of the wrinkle or crease is rubbed, a pinhole is more likely to occur.

  Therefore, a packaging bag for packaging a liquid article and a laminate material constituting the packaging product are required to have a particularly high resistance to pinholes against stress.

  An object of the present invention is to provide a laminated body for a packaging bag in which pinholes are hardly generated even when a stress such as twisting, dropping impact, friction on a bent portion is applied, and a packaging bag composed thereof. It is.

  The present invention is as follows.

<< Aspect 1 >> A laminate having a base material layer and a sealant layer,
The base material layer includes a nylon film or a polyester film,
The sealant layer has a tensile elastic modulus according to JIS K 7127 of 350 MPa or less, and a tear strength according to JIS K 7128 of 6.0 N or more.
Laminated body for packaging bags.
<< Aspect 2 >> The laminate according to <Aspect 1>, wherein the sealant layer has a tensile elastic modulus of 100 MPa to 300 MPa.
<< Aspect 3 >> The laminate according to << Aspect 1 >> or << Aspect 2 >>, wherein the tear strength of the sealant layer is 6.5 N or more and 15.0 N or less.
<< Aspect 4 >> The laminate according to any one of << Aspect 1 >> to <Aspect 3 >>, in which the sealant layer is composed of a polyolefin film containing a chain low density polyethylene.
<< Aspect 5 >> The laminate according to any one of << Aspect 1 >> to << Aspect 4 >>, wherein the base material layer includes a nylon film.
<< Aspect 6 >> The laminate according to any one of << Aspect 1 >> to << Aspect 5 >>, wherein the base material layer has a tensile elastic modulus in accordance with JIS K 7127 of 1,000 MPa or more.
<< Aspect 7 >> The laminate according to any one of <Aspect 1> to <Aspect 6>, further including a surface layer and further including a surface layer, a base material layer, and a sealant layer in this order.
<< Aspect 8 >> The laminate according to <Aspect 7>, in which the surface layer is composed of a polyolefin film containing polypropylene.
<< Aspect 9 >> A packaging bag in which the laminate according to any one of <Aspect 1> to <Aspect 8> is formed into a bag shape.
<< Aspect 10 >> The packaging bag according to << Aspect 9 >>
The contents sealed in the packaging bag;
Including packaging bag with contents.
<< Aspect 11 >> The content-containing packaging bag according to <Aspect 10 >>, wherein the content is a liquid article.

  ADVANTAGE OF THE INVENTION According to this invention, even when twist, a drop impact, the friction to a bending part, etc. are added, the laminated body material which cannot generate | occur | produce a pinhole easily, and a packaging bag comprised from this are provided.

FIG. 1 is a schematic cross-sectional view showing an example of the configuration of the laminate of the present invention. FIG. 2 is a schematic cross-sectional view showing another example of the configuration of the laminate of the present invention.

<Laminate>
An example of the structure of the laminated body for packaging bags of the present invention is shown in FIG. The laminate for a packaging bag of the present invention is
A laminate (10) for a packaging bag having a base material layer (1) and a sealant layer (2),
The substrate layer (1) includes a nylon film,
The sealant layer (2) has a tensile elastic modulus according to JIS K 7127 of 350 MPa or less and a tear strength according to JIS K 7128 of 6.0 N or more.

  The tensile elastic modulus in this specification is a value when tested according to JIS K 7127.

  The tear strength in this specification is a value when tested according to the Elmendorf tear method described in JIS K 7128 Part 2. However, the measurement result is not assigned by the thickness of the test piece, but the average value of the measured tear strength itself is adopted.

  The laminate for a packaging bag of the present invention has improved pinhole resistance by using a base material layer containing a nylon film or a polyester film and a sealant layer having a tensile modulus and tear strength in the above ranges. Yes.

  Nylon film is suitable as a packaging bag material for liquid articles such as food because it has excellent oxygen barrier properties and high toughness. Polyester films, particularly polybutylene terephthalate films, are excellent in fragrance retention and similarly high in toughness, and are therefore used as packaging materials for liquid articles such as highly fragrant foods. However, both nylon and polyester have a high melting point and are difficult to seal with a single film. Also, these films are hard and easily cracked when stress is applied. Therefore, in order to provide the packaging material with a sealing property and resistance to stress in addition to oxygen barrier properties or aroma retaining properties, a base material layer containing a nylon film or a polyester film, a melting point lower than these, and A sealant layer made of a soft material is laminated and used.

  Here, in the laminate for a packaging bag of the present invention, as the sealant layer, a material having a tensile elastic modulus according to JIS K 7127 of 350 MPa or less and a tear strength according to JIS K 7128 of 6.0 N or more is selected. Use.

  A tensile elastic modulus of 350 MPa or less means that it is easily elastically deformed even by a small stress. When a sealant layer that is elastically deformable by stress is used, the stress applied to the laminate is relieved by the deformation of the sealant layer, and the stress applied to the base material layer is reduced. It is considered that the hall property is improved.

  A tear strength of 6.0 N or more means that when a minute crack that does not reach a pinhole occurs, the resistance to expansion of the crack is large. Therefore, when a sealant layer having a tear strength of 6.0 N or more is used, even if a microcrack is generated in the laminate (particularly the base material layer), the crack is difficult to expand. It is considered that it is difficult to occur and the packaging bag is prevented from leaking (breaking bag).

  Therefore, in this invention, the base material layer containing a nylon film or a polyester film is combined with a sealant layer having a tensile elastic modulus according to JIS K 7127 of 350 MPa or less and a tear strength according to JIS K 7128 of 6.0 N or more. By using these, a laminated body for a packaging bag having excellent oxygen barrier properties or perfume retention properties and toughness and exhibiting extremely improved pinhole resistance can be obtained.

Another example of the structure of the laminated body for packaging bags of the present invention is shown in FIG. In this case, the laminate for a packaging bag of the present invention is
In addition to the base material layer (1) and the sealant layer (2), the packaging further comprises a surface layer (3), and the surface layer (3), the base material layer (1), and the sealant layer (2) in this order. It may be a laminate for bags (20), where
The substrate layer (1) includes a nylon film or a polyester film,
The sealant layer (2) has a tensile elastic modulus according to JIS K 7127 of 350 MPa or less and a tear strength according to JIS K 7128 of 6.0 N or more.

  Hereinafter, each layer which comprises the laminated body for packaging bags of this invention is demonstrated in order.

<Base material layer>
A base material layer is a layer containing a nylon film or a polyester film. The polyester film may be, for example, a polybutylene terephthalate (PBT) film.

  In the laminated body for packaging bags of the present invention, since the extremely high pinhole resistance is imparted by the use of the sealant layer according to the present invention, the base material layer may be relatively hard. The base material layer according to the present invention may have a tensile elastic modulus according to JIS K 7127 of, for example, 500 MPa or more, 800 MPa or more, 1,000 MPa or more, 1,500 MPa or more, 2,000 MPa or more, or 2,500 MPa or more. . On the other hand, if the base material layer is excessively hard, there is a risk of inconvenience during manufacture and use of the packaging bag. In order to avoid this, the tensile elastic modulus of the base material layer is, for example, 10,000 MPa or less. Or it may be 5,000 MPa or less.

  For the same reason as described above, the tear strength of the base material layer in the present invention may be relatively small. The base material layer in the present invention has a tear strength according to JIS K 7128 of, for example, 5.0 N or less, 3.0 N or less, 1.0 N or less, 0.50 N or less, 0.30 N or less, or 0.10 N or less. It may be. On the other hand, in order to avoid inconvenience in handling, the tear strength of the base material layer may be, for example, 0.01 N or more, 0.03 N or more, or 0.05 N or more.

  When the tensile modulus and tear strength of the base material layer are different in the MD direction and the TD direction, respectively, it is preferable to satisfy the above requirements in one direction of MD or TD, and in both the MD and TD directions. It is more preferable to satisfy the above requirements.

  Either the stretched film or the unstretched film may be sufficient as the nylon film or polyester film in the base material layer of the laminated body for packaging bags of this invention. When, for example, a nylon film is used as the base material layer in the packaging bag material, an unstretched nylon film has been preferred in the prior art. However, in the laminate of the present invention, a stretched nylon film can be applied in addition to an unstretched nylon film, and a stretched nylon film is preferably used. Stretching may be uniaxial stretching or biaxial stretching. The stretching method in the case of biaxial stretching is arbitrary. For example, a nylon film stretched by tubular biaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching, or the like may be used.

  The base material layer may be a single layer or a multilayer. The multilayer may be constituted by a plurality of films selected from nylon films and polyester films, or a combination of these films and other films. The other film may be, for example, an ethylene-vinyl acetate copolymer. The base material layer in the present invention is typically a single layer of a nylon film or a polyester film having the above preferred characteristics, or a multilayer in which two or more layers selected from such a nylon film and a polyester film are laminated. It may be.

  The base material layer may have a barrier layer on one side or both sides. The barrier layer may be a vapor deposition layer containing, for example, silica, alumina or the like.

  In order to ensure the protection of the contents of the packaging bag, and to provide good toughness while providing the toughness necessary for the laminate and the packaging bag, the thickness of the base material layer is, for example, 5 μm or more, 8 μm or more, It may be 10 μm or more, 12 μm or more, or 15 μm or more, for example, 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less. In the prior art, in order to improve the pinhole resistance of the laminate and the packaging bag, the thickness of the base material layer is designed to be thick. Specifically, the base material layer exceeds 20 μm, typically about 25 μm. Was heavily used. However, in the laminated body for packaging bags of the present invention, by using the base material layer in combination with the sealant layer of the present invention, the expected performance can be exhibited even when the base material layer is thin, for example, 20 μm or less. Typically, it may be about 15 μm.

<Sealant layer>
The sealant layer is a layer having a tensile elastic modulus according to JIS K 7127 of 350 MPa or less and a tear strength according to JIS K 7128 of 6.0 N or more, and may have heat sealability.

  In order to reduce the stress applied to the base material layer, the tensile modulus of the sealant layer is: 350 MPa or less, 300 MPa or less, 250 MPa or less, 200 MPa or less, or 150 MPa or less. On the other hand, in order to ensure the handleability as a laminate, the tensile modulus of the sealant layer may be 100 MPa or more, 110 MPa or more, 120 MPa or more, 130 MPa or more, 140 MPa or more, 160 MPa or more, 180 MPa or more, or 200 MPa or more. . The tensile elastic modulus of the sealant layer may typically be 100 MPa or more and 300 MPa or less.

  When a micro crack is generated in the laminate, the tear strength of the sealant layer is 6.0 N or more, 6.5 N or more, 7.0 N or more in order to sufficiently increase the resistance to the expansion of the crack. It may be 7.5N or more, or 8.0N or more. On the other hand, considering the manufacturing cost or availability, the tear strength of the sealant layer does not need to be excessively large. For example, 15.0 N or less, 12.0 N or less, 10.0 N or less, 9.5 N or less, 9.0 N Or less than or equal to 8.5N. The tear strength of the sealant layer may typically be 6.5N or more and 15.0N or less.

  When the tensile modulus and tear strength of the sealant layer are different in the MD direction and the TD direction, respectively, it is preferable to satisfy the above requirement in one direction of MD or TD, and the above in both the MD and TD directions. It is more preferable to satisfy the requirements.

  The sealant layer may include a layer composed of, for example, a thermoplastic resin.

  Examples of the thermoplastic resin constituting the sealant layer include polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer resin, ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer. (EMAA), polyethylene and the like. Polyethylene is preferable, and specific examples include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), which are selected from these. One or more of these may be used. The sealant layer is preferably composed of a polyolefin film containing LLDPE, and more preferably composed of an LLDPE film, from the viewpoint of imparting good low-temperature heat sealability, workability, and the like.

  The sealant layer may be a single layer composed of one resin layer or a laminate composed of a plurality of resin layers. When the sealant layer is a laminate composed of a plurality of resin layers, the resins constituting each layer may be the same as or different from each other.

  The thickness of the sealant layer is, for example, 30 μm or more, 40 μm or more, 50 μm or more, from the viewpoint of sufficiently increasing the pinhole resistance by protecting the base material layer and ensuring the sealing performance when used as a packaging bag. It may be 60 μm or more. However, the sealant layer need not be excessively thick, and the thickness may be, for example, 200 μm or less, 180 μm or less, 160 μm or less, 140 μm or less, or 120 μm or less.

<Surface layer>
The surface layer optionally used in the laminate for a packaging bag of the present invention is a layer that is laminated on the surface of the base material layer opposite to the sealant layer to protect the base material layer. . That is, in the laminated body for packaging bags of the present invention, the base material layer is protected by the sealant layer, and the generation of pinholes due to stress is suppressed. However, when a laminate having the base material layer disposed on the outermost surface is molded into a packaging bag, the stress on the packaging bag is directly applied to the relatively hard base material layer, and there is no concern about the occurrence of pinholes. Will not be wiped out. Therefore, by further arranging a surface layer in the laminate for packaging bag of the present invention and having a surface layer, a base material layer, and a sealant layer in this order, the base material layer is composed of the surface layer and the sealant layer. It is intended to further improve pinhole resistance by protecting both sides.

  The surface layer is preferably a layer composed of a softer resin than the base material layer, and may include, for example, a layer composed of a thermoplastic resin.

  The thermoplastic resin constituting the surface layer may be, for example, a polyolefin such as polypropylene (PP) or polyethylene; a polyester such as polyethylene terephthalate. For example, when the surface layer is a layer composed of polyolefin such as unstretched PP, monoaxially stretched PP, biaxially stretched PP, and high density polyethylene (HDPE), the resulting packaging bag has pinhole resistance to bending. It will be expensive. When the surface layer is composed of a polyolefin film containing polypropylene, it is preferable because pinhole resistance against bending and friction is high. Particularly, when the surface layer is a biaxially stretched PP film, pinhole resistance against bending and friction is preferable. This is more preferable because the property becomes extremely high. In the laminated body for packaging bags of this invention, it may be preferable not to have surface layers other than the polyolefin film containing a polypropylene.

  The thickness of the surface layer may be, for example, 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more in order to ensure protection of the base material layer, but need not be excessively thick, for example, 50 μm or less, It may be 40 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less.

<< Method for Manufacturing Laminate >>
The laminate for a packaging bag of the present invention may be manufactured by laminating the base material layer and the sealant layer as described above, or the surface layer, the base material layer, and the sealant layer in this order by an arbitrary method. . Specifically, for example, after forming each layer constituting the laminate for a packaging bag of the present invention separately, these layers may be laminated by dry lamination, wet lamination, hot melt lamination, etc .; After forming a part of the layer constituting the laminate for a product, another layer may be formed on the layer by extrusion lamination; each layer constituting the laminate for a packaging bag of the present invention may be formed by coextrusion. Or a combination of a plurality of these methods.

《Packaging bag》
The packaging bag of this invention may be comprised when the laminated body for packaging bags of this invention is shape | molded in a bag shape. As a method for forming the laminated body for a packaging bag of the present invention into a bag shape, specifically, for example, two laminated bodies are prepared and faced so that the sealant layer faces inward, and the peripheral portion of the sealant layer is sealed. The laminate may be formed such that the sealant layer is folded inward so that the sealant layers face each other and the periphery of the sealant layer is sealed; or After forming into a cylinder shape and cutting this cylinder body into a suitable magnitude | size, you may shape | mold by sealing the both ends of a cut. The seal in these methods may be a heat seal, for example.

<Packaging bag with contents>
The packaging bag containing the contents of the present invention includes the packaging bag of the present invention as described above and the contents sealed in the packaging bag.

  The contents of the packaging bag containing the contents may be liquid articles. The liquid article may be, for example, food, medicine, cosmetics, paint, and the like. Examples of the food include beverages, edible oils, soups, creams, liquid seasonings (for example, soy sauce, vinegar, noodle soup, warrior, mirin, Worcester sauce, ketchup, tabasco, sweetener). The medicine includes, for example, injection, infusion, infusion, perfusion, decoction and the like. Cosmetics include, for example, shampoos, conditioners, hair styling agents (for example, hair water, hair liquids, greases, etc.). The paint includes, for example, paint, varnish, oil stain and the like.

<Example 1>
(1) Manufacture of laminated body for packaging bag Nylon film (manufactured by Kojin Film & Chemicals Co., Ltd., product number “RX # 15”, thickness 15 μm) as a base material layer and LLDPE film (Tamapoly Co., Ltd.) as a sealant layer ), Product number “TS200”, thickness 70 μm) was laminated using a dry laminator so that the MD directions of the two coincided with each other to produce a film-like laminate for a packaging bag.

  The characteristics of each layer used here are shown in Table 1.

(2) Evaluation of laminated body for packaging bag (2-1) Bending test The laminated body for packaging bag obtained in (1) above was cut into a rectangular shape of MD direction: 210 mm and TD direction: 286 mm. The cut-out laminated body for packaging bag is made into a cylindrical shape with the sealant layer side on the inside and the MD direction in the height direction, and the axial direction of the cylinder is horizontal to the fixed and movable heads of the gelboflex tester manufactured by Toyo Seiki Seisakusho Co., Ltd. It was fixed to become. Then, a bending test was performed under the following conditions in accordance with the US military specification standard MIL-B-131D, and the number of pinholes after bending 1,000 times was examined.

(Bending test conditions)
The tester's movable head is rotated 440 ° while moving 88.9 mm toward the fixed head, and then moved further 63.5 mm without rotating, and then these operations are reversed to restore the original movement. A series of movements to return the position to one cycle was repeated at a speed of 40 cycles / minute, and a bending test was performed a predetermined number of times.

  This bending test was performed on three laminate samples. Table 2 shows the bending test results of each sample.

(2-2) Transport test Using a bag-making and filling machine “ONPACK 2530” manufactured by ORIHIRO Co., Ltd., the packaging bag made of the packaging bag laminate obtained in (1) above is filled with 1 kg of water and sealed. In addition, a vertical pillow type packaging bag with contents of 300 mm length and 150 mm width was manufactured. Six of the resulting packaging bags with contents were packed in a cardboard box having a length of 340 mm, a width of 245 mm, and a height of 100 mm. At this time, in a corrugated cardboard box, three pieces arranged in a row so that the long sides of the vertical pillows of adjacent packaging bags are in contact with each other were packed in two steps.

  The packed cardboard box was set in a transport packaging tester “BF-100UT” manufactured by IDEX Co., Ltd., and a transport test was performed under the condition of acceleration 3.5G. The apparatus was stopped every test time 20 minutes (transport distance: equivalent to 1,000 km), and the number of packaging bags with broken bags (occurrence of leakage) was examined. The number of samples used for the test was 18 (for three cardboard boxes) up to 1,000 km, and six (for one cardboard box) thereafter. The results are shown in Table 4.

<Examples 2 to 6 and Comparative Examples 1 and 2>
(1) Manufacture of laminated body for packaging bag A laminated body for packaging bag was produced in the same manner as in Example 1 except that each of the LLDPE films shown in Table 1 was used as the sealant layer. Table 1 shows the characteristics of each layer used here (the sealant layer has a thickness of 70 μm).

(2) Evaluation of laminated body for packaging bag (2-1) Bending test A bending test was conducted in the same manner as in Example 1 using the laminated body for packaging bag obtained above. The results are shown in Table 2. Moreover, about the laminated body of Examples 4-6, the frequency | count of bending was continued to 2,000 times, and the pinhole number after 2,000 times bending was also investigated. The results are shown in Table 3.

(2-2) Transport test Using the laminates for packaging bags obtained in Examples 2, 3, and 5 and Comparative Example 1, transport tests were performed in the same manner as in Example 1. At this time, in the transport test in Example 5, the number of samples up to a transport distance of 1,000 km was 42 (for seven cardboard boxes). The evaluation results are shown in Table 4.

<Example 7>
(1) Manufacture of laminated body for packaging bag PP film (Futamura Chemical Co., Ltd., product number “FOR # 20”, thickness 20 μm) as a surface layer and nylon film (Kojin Film & Chemicals ( Co., Ltd., product number “RX # 15”, thickness 15 μm) and LLDPE film (manufactured by Tamapoli Co., Ltd., product number “TS200:”, thickness 70 μm) as a sealant layer using a dry laminator By laminating in the order described above so that the directions coincided, a film-like laminate for a packaging bag was produced. The characteristics of each layer used here are shown in Table 1.

(2) Evaluation of laminated body for packaging bag Evaluation was performed in the same manner as in Example 1 using the laminated body for packaging bag obtained above. The evaluation results are shown in Tables 2 and 4.

<Examples 8 to 10>
A laminate for a packaging bag was produced in the same manner as in Example 5 except that the films shown in Table 1 were used as the surface layer and the sealant layer, respectively, and subjected to a bending test and a transportation test.

  The characteristics of each layer used here are shown in Table 1. The evaluation results are shown in Tables 2 and 4.

  The following is understood with reference to Tables 1-4.

  A laminate for a packaging bag having a base material layer and a sealant layer, comprising: a base material layer made of nylon; and a sealant layer made of LLDPE having a tensile modulus of elasticity exceeding 350 MPa and / or a tear strength of less than 6.0 N. In the laminates of Comparative Examples 1 and 2 used, pinholes sometimes occurred after bending 1,000 times when a bending test based on MIL-B-131D was performed. On the other hand, in the laminates for packaging bags of Examples 1 to 6 using the sealant layer made of LLDPE having a tensile modulus of 350 MPa or less and a tear strength of 6.0 N or more, Pinholes did not occur after 1,000 bends (see Tables 1 and 2).

  Looking at Examples 4 to 6 in which the thickness of the sealant layer was changed, there was no substantial effect on the bending resistance when the thickness of the sealant layer was at least 40 μm or more and 100 μm or less. Pinholes did not occur after 1,000 times of bending, and pinholes after 2,000 times of bending were negligible (see Table 3).

  Moreover, the packaging bag containing the contents obtained from the laminate of Comparative Example 1 was subjected to a test in which a bag breakage occurred in 4 of 18 test bags at a transport distance equivalent to 1,000 km in the transport test. The laminates containing the contents of Examples 1 to 3 and 5 exhibited excellent transport resistance.

  The laminated body for packaging bags of Examples 7 to 10 which further has a surface layer and has a surface layer, a base material layer, and a sealant layer in this order have pinholes after bending 1,000 times in the bending test under the above conditions. It did not occur and showed excellent transport resistance in the transport test of the packaging bag with contents.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Sealant layer 3 Surface layer 10, 20 Laminate for packaging bag

Claims (11)

A laminate having a base material layer and a sealant layer,
The base material layer includes a nylon film or a polyester film,
The sealant layer has a tensile elastic modulus according to JIS K 7127 of 350 MPa or less, and a tear strength according to JIS K 7128 of 6.0 N or more.
Laminated body for packaging bags.   The laminated body of Claim 1 whose tensile elasticity modulus of the said sealant layer is 100 Mpa or more and 300 Mpa or less.   The laminate according to claim 1 or 2, wherein the tear strength of the sealant layer is 6.5N or more and 15.0N or less.   The laminated body as described in any one of Claims 1-3 comprised from the polyolefin film in which the said sealant layer contains linear low density polyethylene.   The laminated body as described in any one of Claims 1-4 in which the said base material layer contains a nylon film.   The said base material layer is a laminated body as described in any one of Claims 1-5 whose tensile elasticity modulus based on JISK7127 is 1,000 Mpa or more.   The laminate according to any one of claims 1 to 6, further comprising a surface layer, further comprising a surface layer, a base material layer, and a sealant layer in this order.   The laminate according to claim 7, wherein the surface layer is composed of a polyolefin film containing polypropylene.   The packaging bag by which the laminated body as described in any one of Claims 1-8 is shape | molded by the bag shape. A packaging bag according to claim 9;
The contents sealed in the packaging bag;
Including packaging bag with contents.   The packaging bag with contents according to claim 10, wherein the contents are liquid articles.

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