JP2011201587A - Laminated film for food package bag easily opened and food package bag easily opened - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film for a food package bag easily opened which can prevent invasion of a foreign substance and provides easy opening property and maintains convenience that it can be opened and closed repeatedly with a binder or the like and does not cause deterioration of fusion strength and impact resistance in accompany with thin film and makes it possible to reduce packaging material and provide a bag for the food package bag easily opened composed of the laminated film.SOLUTION: The laminated film for food package bag easily opened includes a surface layer containing a propylene based resin, a middle layer made of a resin mixture essentially consist of a propylene based resin and an ethylene based resin, and the propylene resin is 50 mass% or above and the ethylene based resin is 5 mass% or above, and the total of them is 80 mass% or above, and a heat seal layer containing 1-butene based copolymer which essentially consist of 1-butene and propylene, and a copolymer which essentially consists of a propylene and an ethylene polymerized using a metallocene based catalyst.

Description

  The present invention is suitable for food packaging such as bread and confectionery bread provided with an easy-open seal part that can prevent the intrusion of foreign matter, and is a laminated film for easy-open food packaging bags that does not deteriorate in strength and the like due to thinning, The present invention relates to an easily opened food packaging bag made of this laminated film.

  In recent years, packaging such as bread is being transported and sold after sealing and sealing the opening after packaging in order to improve consumer safety awareness and prevent foreign matter contamination and tampering. . This seal part is required to be easily openable from the viewpoint of universal design. Furthermore, when there are multiple contents, or when a large food package is packaged even if it is a single product package, It is also required that the bag can be opened and closed many times by using a binder (plastic plate, tape, string, etc.) that does not break and can be resealed.

  In order to meet such a demand, the present inventors have already provided an easily openable multilayer film for food packaging and an easily openable food packaging bag obtained therefrom (for example, see Patent Document 1).

  On the other hand, since the Containers and Packaging Recycling Law was enacted in 1996 from the viewpoint of environmental protection, food packaging materials have been required to be reduced. In particular, food manufacturers have commissioned re-commercialization according to the quantity of packaging materials used. Is required, and thinning the packaging material is an urgent issue.

JP 2006-213065 A

  In view of the above situation, the object of the present invention is to prevent the intrusion of foreign matter, have easy opening, maintain the convenience that the packaging bag can be opened and closed many times with a binding tool, etc. An object of the present invention is to provide a laminated film for an easy-open food packaging bag in which the fusing strength and impact strength are not deteriorated and the packaging material can be reduced, and an easy-open food packaging bag made of this laminated film.

  As a result of intensive studies to solve the above problems, the present inventor has obtained a surface layer containing a propylene-based resin, an intermediate layer containing a propylene-based resin and an ethylene-based resin in a specific ratio, and , A heat-seal layer comprising a 1-butene copolymer and a propylene-ethylene copolymer polymerized using a metallocene catalyst, the total thickness of which is thinner than that of the conventional product. Even if designed, a food packaging bag having excellent fusing strength, easily heat-sealable and having an opening portion that can be easily opened is obtained, and further, practical rigidity and impact strength as a food bag are provided. The present invention was completed.

  That is, the present invention comprises a surface layer (A) containing a propylene resin, a propylene resin (b1) and an ethylene resin (b2) as essential components, and 50% by mass of the resin component forming the layer. The above is the propylene resin (b1), and 5% by mass or more is the ethylene resin (b2), and the total of (b1) and (b2) is 80% by mass or more. An intermediate layer (B) made of a resin mixture, a 1-butene copolymer (c1) having 1-butene and propylene as essential components, propylene and ethylene polymerized using a metallocene catalyst A heat seal layer (C) comprising a copolymer (c2) as an essential component, and a laminated film for easy-open food packaging bags, and a heat seal layer ( B) Characterized in that the bag-making and hot-melt adhesive as the inner, there is provided an easy-open food packaging bag having an opening.

  The laminated film for easy-opening food packaging bags of the present invention is a temperature at which the heat seal layer melts, with the heat seal resin layer inside, even in a design in which the total thickness is thinner than the laminate film conventionally used in the same application. When heat sealing or fusing sealing is performed as described above, a food packaging bag having the same strength as the conventional one is obtained, and the obtained bag is filled with food, and at a lower temperature, for example, 100 ° C. or less. By heat-sealing the opening, even if the heat-sealing temperature varies somewhat, it becomes an easy-opening seal with stable sealing strength, and an easy-open packaging bag in which food is easily sealed can be obtained. The easy-open food packaging bag thus obtained has an easy-open seal so that foreign matter can be prevented from entering, and it can be easily opened at the easy-open seal portion, and propylene resin and ethylene can be used as an intermediate layer of the laminated film. Because it uses a resin blended with a specific proportion of resin, there is no deterioration of rigidity and impact strength, and the bag does not break when opened, etc., so it can be resealed with a binder such as a plastic plate, tape, string, etc. Furthermore, by binding the upper part of the bag with a binding tool, it is possible to obtain a binding package similar to the conventional bread packaging.

  Therefore, the easy-open food packaging bag obtained by using the laminated film for easy-open food packaging bags of the present invention can realize a thin film for twist bag packaging or horizontal pillow packaging of bread, snacks, fruits and vegetables. The practical value is tremendous.

  The laminated film of the present invention comprises a surface layer (A) containing a propylene-based resin, a propylene-based resin (b1) and an ethylene-based resin (b2) as essential components, and 50 mass of a resin component forming the layer. % Or more is the propylene resin (b1), and 5% by mass or more is the ethylene resin (b2), and the total of (b1) and (b2) is 80% by mass or more. An intermediate layer (B) comprising a blended resin mixture, a 1-butene copolymer (c1) containing 1-butene and propylene as essential components, and propylene and ethylene polymerized using a metallocene catalyst And a heat seal layer (C) containing a copolymer (c2) as an essential component.

  Examples of the propylene resin used as the resin for the surface layer (A) include propylene homopolymers; random copolymers composed of propylene and ethylene, block copolymers composed of propylene and ethylene, and other than propylene and ethylene. And a propylene-based resin such as a copolymer with an α-olefin, and may be used alone or in admixture of two or more. The surface layer (A) contains the propylene-based resin as a main component, and preferably contains 75% by mass or more, and if necessary, an ethylene-1-butene copolymer, a linear low-density polyethylene. Such other thermoplastic resins and various additives may be mixed and used.

  The resin for the intermediate layer (B) is a mixture of propylene-based resin (b1) and ethylene-based resin (b2), and is used by mixing other thermoplastic resins and various additives as necessary. However, 50% by mass or more of the total resin forming the intermediate layer (B) is a propylene-based resin (b1), and similarly 5% by mass or more is an ethylene-based resin (b2), It is essential that the total of (b1) and (b2) be 80% by mass or more of the entire resin, 70% by mass or more is the propylene-based resin (b1) and 10% by mass. The ethylene resin (b2) is preferable from the viewpoint that deterioration of rigidity and impact strength when the total thickness of the laminated film is designed to be thin can be easily prevented.

  As the propylene-based resin (b1), any of the propylene-based resins exemplified in the surface layer (A) can be preferably used, or a single type or a mixture of two or more types may be used. Among these, a propylene copolymer obtained by copolymerizing propylene homopolymer or propylene and ethylene as essential components from the viewpoint of obtaining a laminated film having a better balance between rigidity and impact strength is preferable. In the case of the copolymer, it is particularly preferable to use a copolymer obtained using a metallocene catalyst described later.

  Examples of the ethylene resin (b2) include low density polyethylene, linear low density polyethylene, medium density polyethylene, and high density polyethylene, and each may be used alone or in combination of two or more. May be. Among these, it is preferable to use linear low density polyethylene from the viewpoint of obtaining a laminated film having a better balance between rigidity and impact strength.

  The resin for the heat seal layer (C) is composed of 1-butene copolymer (c1) having 1-butene and propylene as essential components, and propylene and ethylene polymerized using a metallocene catalyst as essential components. And a copolymer (c2). As the mixing ratio (c1) / (c2), the range of 1/4 to 1/1 (mass ratio) is easy to adjust the heat seal temperature and strength in the obtained laminated film. It is preferable because the heat seal temperature range is wide and appropriate heat seal strength can be easily obtained as an easy-open seal. Moreover, as 1-butene type copolymer (c1) used at this time, the thing whose content rate of a 1-butene origin component is 50-99 mol% is especially preferable.

  The copolymer (c2) comprising propylene and ethylene polymerized using the metallocene catalyst as essential components is a copolymer polymerized using a metallocene catalyst instead of the conventional Ziegler-Natta catalyst. . Examples of the metallocene catalyst include a metallocene homogeneous mixed catalyst containing a metallocene compound and an aluminoxane, a metallocene supported catalyst in which a metallocene compound is supported on a particulate carrier, and the like. The metallocene supported catalyst is disclosed in JP-A-5-155931, JP-A-8-104691, JP-A-8-157515, JP-A-8-231621, and the like. Resin polymerized with metallocene catalyst has high uniformity in molecular weight distribution and composition distribution and low content of low molecular weight components, so it suppresses the deterioration of fusing seal strength that occurs when the total thickness of the laminated film is designed thin. Winding quality (appropriate winding with a winder during production, that is, the friction coefficient immediately after film formation decreases, making it easy to slip and suppressing the occurrence of wrinkles during winding) It is modified to improve productivity.

  The above-mentioned heat seal layer (C) has a heat seal start temperature measured in accordance with a heat seal start temperature test defined in JIS K-1713 lower than the heat seal start temperature of the surface layer (A). It is preferable because the bag is easy to produce and easy to open and seal. For this reason, as a laminated | multilayer film of this invention, it is preferable that the heat seal start temperature difference between a surface layer (A) and a heat seal layer (C) shall be 30 degreeC or more, and shall be 35-90 degreeC especially. Is particularly preferred.

  The laminated film of the present invention is a three-layer film obtained by laminating a surface layer (A), an intermediate layer (B), and a heat seal layer (C) in the order of (A) / (B) / (C). Although it is good, it is possible to divide the intermediate layer (B) into two or more layers in consideration of film rigidity, cold resistance, productivity, etc., and there is no problem even if the total layer structure becomes four layers or more. No.

  Although the thickness of the laminated film of the present invention is not limited at all, it can be made 5 to 15% thinner than the thickness of the laminated film conventionally used in the same application, and is usually 15 to 50 μm. In particular, it is preferable to design in the range of 20 to 40 μm. Moreover, although the thickness of a heat seal layer (C) is 0.1-10 micrometers normally, it is preferable to design so that it may become the range of 1-8 micrometers especially.

  When the laminated film of the present invention is a three-layer film laminated in the order of (A) / (B) / (C), the thickness ratio with respect to the total thickness of the surface layer (A) and the intermediate layer (B) is: Although it varies depending on the resin composition of each layer and is not particularly limited, the surface layer (A) is usually 10 to 50%, preferably 15 to 45%, and the intermediate layer (B) is usually 30 to 80%, preferably 40 to 70%. It is.

As a specific example of the laminated film of the present invention, for example,
(I) A surface layer (A1) containing 75% by weight or more of a propylene-based copolymer containing propylene and ethylene as essential components, 70% by weight or more of a propylene homopolymer, and 10% of a linear low density polyethylene % Intermediate layer (B1), 1-butene copolymer (c1), copolymer (c2) comprising propylene and ethylene polymerized using a metallocene catalyst as essential components Of the heat seal layer (C1) containing 1/4 to 1/1 (mass ratio) in the order of (A1) / (B1) / (C1), the ratio of the average thickness is 2 A three-layer film (I-) suitable for a bag having a thickness of 25 μm or 28 μm and laminated with a gusset at the bottom (hereinafter referred to as a bottom gusset bag). 1),
(Ii) A surface layer (A2) containing 90% by weight or more of a propylene homopolymer, 70% by weight or more of a propylene homopolymer and / or a copolymer containing propylene and ethylene as essential components, linear The intermediate layer (B2) containing 10% by mass or more of the low-density polyethylene and the same heat seal layer (C2) as (C1) in the order of (A2) / (B2) / (C2) A three-layer film (I-2) suitable for a pillow packaging bag having a thickness of 25 μm or 28 μm, which is laminated so that the thickness ratio is 2-3: 6-7: 1
(Iii) A propylene homopolymer and / or a surface layer (A3) containing 80% by weight or more of a propylene copolymer containing propylene and ethylene as essential components, and a propylene system containing propylene and ethylene as essential components An intermediate layer (B3) containing 50% by mass or more of a copolymer and 10% by mass or more of a linear low-density polyethylene, and the same heat seal layer (C3) as (C1), (A3) / (B3) / (C3) are laminated in order of the average thickness ratio of 2 to 3: 5 to 6: 1. The thickness is 25 μm or 28 μm and is suitable for the bottom gusset bag. Examples thereof include a three-layer film (I-3).

  The laminated film of the present invention may be used as it is, but the surface layer (A) may be subjected to corona discharge treatment in order to improve product appeal by printing. In addition, in each layer of the laminated film, additives such as an antioxidant, a slip agent, an antiblocking agent, an antifogging agent, a colorant, and silica, etc., as necessary, in a range that does not impair the effects of the present invention. You may add suitably.

  The method for producing the laminated film of the present invention is not particularly limited, and among these, the coextrusion molding method and the extrusion laminating method are preferable, and the coextrusion molding method is particularly preferable.

  Below, the easy-open food packaging bag and method of this invention are demonstrated by exemplifying the bread packaging method and the accumulation packaging method of various bread.

(1) Bread bread packaging method For bread bread packaging method, it is usually preferable to use the above-described three-layer film (I-1) or (I-3). After the three-layer film (I-1) or (I-3) is printed, the bottom of the three-layer film (I-1) or (I-3) is formed by a bag making machine such as HK-40 manufactured by Totani Giken Co., Ltd. Process into gusset bags. At this time, the fusing seal temperature and the bag making speed are adjusted so that the fusing seal strength of the side part of the bottom gusset bag and the bottom gusset part (folded part of the bottom part) is 7.5 to 30 N / 15 mm, preferably 12 to 30 N / 15 mm. adjust. Subsequently, the obtained bottom gusset bag is supplied to a bread bread automatic filling machine, and after filling bread, it is easy to open and has a heat seal strength of 0.1 to 5 N / 15 mm, preferably 0.2 to 3.5 N / 15 mm. Heat-sealing under the conditions to make an easily openable bread packaging bag, and if necessary, the upper part of the bag, preferably the upper part of the bread, the portion of the easily openable seal or near or above the plastic plate, tape, Bundling using a binding tool such as a string. The easy-open food packaging bag may be made and the food may be packaged immediately, or an easy-open food packaging bag pre-made by a third party is prepared and used. Food packaging may be performed.

(2) Packaging method for a plurality of confectionery breads It is usually preferable to use a three-layer film (I-2) for collecting and packaging various breads such as butter rolls. After the three-layer film (I-2) is printed, it is rolled in a horizontal pillow type automatic packaging machine such as FW-3400αV type manufactured by Fujikikai Co., Ltd. so that the heat seal layer is inside the bag. Supply. In the horizontal pillow type automatic packaging machine, the heat seal surface of the film is overlapped and heat sealed to create a bag and to enclose the bread. At this time, the heat seal temperature and the packaging speed are adjusted so that the sealing strength of the bottom portion and the back pasting portion of the pillow packaging bag by the packaging machine is 7.5 to 30 N / 15 mm, preferably 8 to 20 N / 15 mm. Next, heat-sealing is carried out under conditions that allow easy opening and a heat seal strength of 0.1 to 5 N / 15 mm, preferably 0.2 to 3.5 N / 15 mm, and further, as required. Then, at the upper part of the bag, preferably the upper part of the bread, the easy-open seal part or the upper or lower part thereof is bound using a binding tool such as a plastic plate, tape, or string.

  The easy-open seal referred to in the present invention refers to the heat seal strength of a test piece having a width of 15 mm cut out from the heat seal portion of the bag, using a tensile tester [Tensilon manufactured by A & D Co., Ltd.] Heat seal strength of 0.1 to 5 N / 15 mm when measured at a temperature of 23 ° C. and a tensile speed of 300 mm / min, and 80% or more of the test piece peels off from the sealing surface without breaking the film Say.

  With the food packaging method of (1) or (2) above, as the sealing temperature and sealing time for heat-sealing after bread filling, easy opening and heat-sealing strength of 0.1 to 5 N / 15 mm Although it varies depending on the seal pattern and seal pressure, it is not particularly limited, but it is preferably 65 to 95 ° C for 0.1 to 2 seconds, particularly preferably 70 to 90 ° C for 0.3 to 1.5 seconds.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the examples, all parts and% are based on mass unless otherwise specified.

Example 1
As the surface layer (A), propylene-ethylene copolymer (ethylene-derived component content: 5.8%, density: 0.90 g / cm ³ , melt index (hereinafter referred to as MI): 6 g / 10 minutes, melting point 140 C)) 90 parts and 10 parts of crystalline ethylene-1-butene copolymer (density: 0.88 g / cm ³ , MI: 4 g / 10 minutes, hereinafter referred to as “EBR”) As (B), 90 parts of a propylene homopolymer (density: 0.90 g / cm ³ , MI: 9 g / 10 minutes, melting point 163 ° C., hereinafter referred to as “HOPP-1”) and linear low density polyethylene ( ^{density: 0.905g / cm 3, MI:} . 4g / 10 min, hereinafter referred to as "LLDPE") a mixture of a 10 parts, as a heat sealing layer (C), propylene-1-butene copolymer (density ^{0.90g / cm 3, MI: 4g} / 10 minutes) 40 parts of a metallocene catalyst system propylene - ethylene copolymer (ethylene-derived ingredient content: 4.0% ^{Density: 0.90g / cm 3, MI:} 7g / The mixture consisting of 60 parts for 10 minutes, melting point 130 ° C. is supplied to each of three extruders, the average thickness of the heat seal layer (A), the intermediate layer (C) and the surface layer (B) is 7, 18 and 3 μm were co-extruded to form a 28 μm thick three-layer film. Next, the surface layer (A) of the obtained three-layer film was subjected to corona discharge treatment so that the surface energy of the surface layer (A) was 33 mN / m, to obtain a laminated film.

Example 2
As the surface layer (A), a propylene-ethylene block copolymer (density: 0.90 g / cm ³ , MI: 8 g / 10 minutes, melting point 160 ° C., hereinafter referred to as “BCOPP”) is used as the intermediate layer (B). The same procedure as in Example 1 was performed except that a mixture of 90 parts of BCOPP and 10 parts of LLDPE was used, and the thickness of each layer (A) / (B) / (C) was 9, 16, and 3 μm. A co-extruded multilayer film consisting of 3 layers having a thickness of 28 μm was obtained. Next, the surface of the surface layer (A) of the obtained coextruded multilayer film was subjected to corona discharge treatment so that the surface energy was 33 mN / m in the same manner as in Example 1 to obtain a laminated film.

Example 3
As heat seal layer (C), 20 parts of propylene-1-butene copolymer (density: 0.90 g / cm ³ , MI: 4 g / 10 min) and metallocene catalyst propylene-ethylene copolymer (content of ethylene-derived components) : 4.0%, density: 0.90 g / cm ³ , MI: 7 g / 10 min, melting point 130 ° C.), except that the mixture was changed to 80 parts. A coextruded multilayer film consisting of layers was obtained. Next, the surface of the surface layer (A) of the obtained coextruded multilayer film was subjected to corona discharge treatment so that the surface energy was 33 mN / m in the same manner as in Example 1 to obtain a laminated film.

Example 4
As in Example 1, except that HOPP-1 was used as the surface layer (A) and the thickness of each layer (A) / (B) / (C) was 9, 16, 3 μm, A co-extruded multilayer film consisting of 3 layers having a thickness of 28 μm was obtained. Subsequently, the surface of the surface layer (A) of the obtained coextruded multilayer film was subjected to corona discharge treatment so that the surface energy was 36 mN / m in the same manner as in Example 1 to obtain a laminated film.

Example 5
HOPP-1 was used as the surface layer (A), and a mixture of 95 parts of HOPP-1 and 5 parts of LLDPE was used as the intermediate layer (B). The thickness of each layer (A) / (B) / (C) was 7 16 and 2 μm, a coextruded multilayer film consisting of 3 layers having a thickness of 25 μm was obtained in the same manner as in Example 2. Subsequently, the surface of the surface layer (A) of the obtained coextruded multilayer film was subjected to corona discharge treatment so that the surface energy was 36 mN / m in the same manner as in Example 1 to obtain a laminated film.

Example 6
HOPP-1 was used as the surface layer (A), and 80 parts of HOPP-1 and low density polyethylene (density: 0.919 g / cm ³ , melting point: 107 ° C., hereinafter referred to as “LDPE” as the intermediate layer (B). A co-extruded multilayer film consisting of 3 layers having a thickness of 28 μm was obtained in the same manner as in Example 1 except that the mixture was 20 parts. The surface of the surface layer (A) of the obtained coextruded multilayer film was subjected to corona discharge treatment so that the surface energy was 36 mN / m in the same manner as in Example 1 to obtain a laminated film.

Example 7
HOPP-1 is used as the surface layer (A), 65 parts of HOPP-1 and medium density polyethylene (density: 0.93 g / cm ³ , melting point 126 ° C., hereinafter referred to as “MDPE”) as the intermediate layer (B) .) A co-extruded multilayer film consisting of 3 layers having a thickness of 28 μm was obtained in the same manner as in Example 1 except that the mixture was mixed with 35 parts. The surface of the surface layer (A) of the obtained coextruded multilayer film was subjected to corona discharge treatment so that the surface energy was 36 mN / m in the same manner as in Example 1 to obtain a laminated film.

Example 8
HOPP-1 is used as the surface layer (A), and a mixture of 50 parts of HOPP-1 and 50 parts of LLDPE is used as the intermediate layer (B). The thickness of each layer (A) / (B) / (C) is A coextruded multilayer film consisting of 3 layers having a thickness of 25 μm was obtained in the same manner as in Example 2 except that the thickness was 7, 16, and 2 μm. Subsequently, the surface of the surface layer (A) of the obtained coextruded multilayer film was subjected to corona discharge treatment so that the surface energy was 36 mN / m in the same manner as in Example 1 to obtain a laminated film.

Comparative Example 1
As the intermediate layer (B), a propylene homopolymer (density: 0.90 g / cm ³ , MI: 9 g / 10 minutes, melting point 160 ° C., hereinafter referred to as “HOPP-2”) is used as the heat seal layer (C). , 40 parts of propylene-1-butene copolymer and Ziegler-Natta catalyst propylene-ethylene copolymer (ethylene-derived component content: 5.0%, density: 0.90 g / cm ³ , MI: 7 g / 10 minutes) Three layers having a thickness of 30 μm were used in the same manner as in Example 1 except that a mixture of 60 parts was used and the thicknesses (A) / (B) / (C) were 7, 20, and 3 μm. A film was formed. Next, the surface layer (A) of the obtained three-layer film was subjected to corona discharge treatment so that the surface energy of the surface layer (A) was 33 mN / m, to obtain a laminated film.

Comparative Example 2
A three-layer film having a thickness of 28 μm was formed so that the thickness of (A) / (B) / (C) was 7, 18, 3 μm with the same configuration as Comparative Example 1. Next, the surface layer (A) of the obtained three-layer film was subjected to corona discharge treatment so that the surface energy of the surface layer (A) was 33 mN / m, to obtain a laminated film.

Comparative Example 3
A three-layer film having a thickness of 28 μm was formed in the same manner as in Comparative Example 2 except that a mixture of 90 parts of HOPP-1 and 10 parts of LLDPE was used as the intermediate layer (B). Next, the surface layer (A) of the obtained three-layer film was subjected to corona discharge treatment so that the surface energy of the surface layer (A) was 33 mN / m, to obtain a laminated film.

Comparative Example 4
A three-layer film having a thickness of 28 μm was formed in the same manner as in Example 1 except that a mixture of 97 parts of HOPP-1 and 3 parts of LLDPE was used as the intermediate layer (B). Next, the surface layer (A) of the obtained three-layer film was subjected to corona discharge treatment so that the surface energy of the surface layer (A) was 33 mN / m, to obtain a laminated film.

Comparative Example 5
A three-layer film having a thickness of 28 μm was formed in the same manner as in Example 1 except that a mixture of 45 parts of HOPP-1 and 55 parts of LLDPE was used as the intermediate layer (B). Next, the surface layer (A) of the obtained three-layer film was subjected to corona discharge treatment so that the surface energy of the surface layer (A) was 33 mN / m, to obtain a laminated film.

The film obtained above was evaluated based on the following.
Measurement of rigidity Based on ASTM D-882, a 1% tangential modulus (unit: MPa) at 23 ° C. was measured with respect to the extrusion direction (hereinafter referred to as “MD”) during film production. And D made] and measured.

Measurement of impact strength Using the obtained film, the sample was held for 6 hours in a temperature-controlled room adjusted to 23 ° C., and then measured by a film impact method using a spherical impact head having a diameter of 25.4 mm.

Measurement of fusing seal strength After the film is folded in half with the heat seal layer (C) of the obtained film inside, a gusset is put in the bottom, and fusing and sealing is performed at a sealing temperature of 298 ° C. (bag making temperature). Bag machine: HK-40 manufactured by Totani Giken Kogyo Co., Ltd., bag making speed: 120 sheets / min] to obtain a gusset bag of length: 345 mm (side portion: 245 mm, gusset portion: 60 mm) and width 235 mm. Then, from the center of the side parts on both sides of the upper part of the five bottom gusset bags obtained, 10 pieces of test pieces each having a width of 15 mm (2 pieces each in one bag) were cut out in total, and 23 pieces The maximum load at the time of peeling with a Tensilon tensile tester (manufactured by A & D Co., Ltd.) under the conditions of ° C and a tensile speed of 300 mm / min was determined as the fusing seal strength.

Measurement and evaluation of seal strength Two of the obtained films were overlapped so that the seal layers were in contact with each other, the upper seal bar was fixed at a temperature of 80 ° C, the lower seal bar was fixed at 50 ° C, and the seal was 10 mm wide at a pressure of 0.2 MPa. After heat-sealing with a bar for 1.0 second, the specimen was allowed to cool and then a 15 mm wide test piece was cut out from the heat-sealed film, and the Tensilon tensile tester [A Co., Ltd. The maximum load at the time of peeling off was measured with “And Day”, and the maximum load was defined as the seal strength (unit: N / 15 mm).

Evaluation of winding quality In order to commercialize a film, it is necessary to wind it uniformly without any wrinkling in the film width direction in a winder (film winding device in a production line) during film formation. And in order to obtain appropriate winding quality, in addition to optimizing the winding conditions in production, appropriate slipperiness of the film surface (front and back surfaces) is also required. The evaluation of the slipperiness of the film surface (front and back surfaces) was carried out by inclining method (friction angle) on the corona-treated surface and non-treated surface of the obtained film at 23 ° C. immediately after film formation (after 5 minutes). The angle (θ) at which the test piece slides is measured with a measuring machine to obtain a friction coefficient value. Based on the obtained value, the winding quality was evaluated based on the following evaluation criteria.
Winding quality ○: Friction coefficient value: <1.1
Winding quality Δ: Friction coefficient value: 1.1 to 1.4
Winding quality x: Friction coefficient value:> 1.4

Claims (8)

A surface layer (A) containing a propylene-based resin;
Propylene resin (b1) and ethylene resin (b2) are essential components, and 50% by mass or more of the resin component forming the layer is the propylene resin (b1), and 5% by mass or more is the ethylene. An intermediate layer (B) made of a resin mixture which is a resin (b2) and is blended so that the total of (b1) and (b2) is 80% by mass or more,
A 1-butene copolymer (c1) comprising 1-butene and propylene as essential components, and a copolymer (c2) comprising propylene and ethylene polymerized using a metallocene catalyst as essential components. A heat seal layer (C) comprising,
A laminated film for an easy-open food packaging bag, comprising: The propylene-based resin (b1) is a propylene homopolymer or a propylene-based copolymer containing propylene and ethylene as essential components, and the ethylene-based resin (b2) is a linear low-density polyethylene. The laminated film for easy-opening food packaging bags described. 1-butene in the copolymer (c1) is contained at a ratio of the mass ratio (c1) / (c2) of the copolymers (c1) and (c2) of 15/60 to 60/15 The laminated film for easy-open food packaging bags according to claim 1 or 2, wherein the content of the derived component is 50 to 99 mol%. The laminated film for easily opened food packaging bags according to any one of claims 1 to 3, wherein the laminated film has a thickness of 15 to 50 µm and the thickness of the heat seal layer (C) is 1 to 8 µm. . An opening comprising the laminated film for an easy-open food packaging bag according to any one of claims 1 to 4, wherein the heat-sealed layer (B) is melt-bonded to the inside to form a bag. Easy-to-open food packaging bag. 6. The easy-open food packaging bag according to claim 5, wherein the opening is heat-sealed so that its strength is in a range of 0.1 to 5 N / 15 mm. The easy-open food packaging bag according to claim 5 or 6, wherein the bag is a bag formed so that a gusset is placed in the bottom. The easy-open food packaging bag according to any one of claims 5 to 7, which is a bread packaging bag.