JP2019034549A - Easy peel sealant film and package - Google Patents

Abstract

An object of the present invention is to provide an easy-peelable sealant film that exhibits good peeling appearance even in a heat-sealing temperature range of 180°C or higher, has stable peel strength (seal strength), and is easy to peel. Kind Code: A1 An easy-peel sealant film 1 comprising a coextruded laminated film of at least a base layer 11 and a seal layer 12, wherein the base layer 11 is low-density polyethylene, medium-density polyethylene, high-density polyethylene, or polypropylene. The sealing layer 12 is composed of a resin composition containing, as a main component, at least one selected from: 60 to 90% by mass of polypropylene and 40 to 10% by mass of low-density polyethylene, The propylene consists of 20-80% by weight of polypropylene produced using a metallocene catalyst and 80-20% by weight of polypropylene produced using a Ziegler-Natta catalyst. [Selection drawing] Fig. 1

Description

  The present invention relates to a heat sealable film (sealant film) having easy peelability (easy peelability, easy openability).

  Conventionally, various types of plastic molded containers have been developed, and articles such as food and drink are filled therein, and then the lid of the container is heat sealed to seal the opening of the container. Packaging products are manufactured.

  The lid material is usually constituted by a laminate of a substrate sheet and a heat sealable film, or a laminate of a substrate sheet, a gas barrier substrate (layer or film) and a heat sealable film.

  The heat sealable film constituting the lid has a sealing property when sealing the opening of the container by heat sealing, and an easy peelability (openability, easy peelability) that can easily open the opening at the time of opening. Is required.

Therefore, the heat sealable film which consists of various lamination composition is proposed about the heat sealable film which constitutes a lid material.
As such a film, for example, in Patent Document 1, in a film formed by co-extruding an olefin resin layer, an easy peelable resin blend resin layer, and a processability improving resin layer, the resin blend resin layer is PP and Disclosed is a method for producing a coextruded easy peel film obtained by blending PE.
However, in this technology, a three-layer configuration of the olefin resin layer, the different resin blend resin layer, and the processability improving resin layer is essential. In addition, at the time of opening, threading or the like occurs, and there is a problem that appearance of the peeled surface becomes remarkably poor.

Further, for example, Patent Document 2 describes a heat sealable laminated film comprising at least two layers,
(A) The first layer to be the seal layer is ethylene / methacrylic acid copolymer, ethylene / methyl methacrylate copolymer, ionomer, ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer and ethylene · Blend polymer of at least one polymer (S1) selected from the group consisting of methyl acrylate copolymer and at least one polymer (S2) selected from the group consisting of polyethylene, polypropylene and ethylene-propylene copolymer The first layer has a thickness of 20 μm or less, and a cohesive failure strength in the range of 50 to 1,000 g / 15 mm width,
(B) The second layer adjacent to the first layer is ethylene / methacrylic acid copolymer, ethylene / methyl methacrylate copolymer, ionomer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene · A layer containing at least one polymer selected from the group consisting of ethyl acrylate copolymer, ethylene / methyl acrylate copolymer and maleic acid graft polymer thereof, wherein the cohesive failure of the second layer is caused. The strength is 1.5 times or more of the cohesive failure strength of the first layer,
(C) An easy peel coextruded laminated film has been proposed which is characterized in that at least the first layer and the second layer are laminated by coextrusion.

  However, the technology of Patent Document 2 has a problem that sufficient heat sealability and easy peelability can not be stably obtained when the heat seal temperature is high. Therefore, when the object of heat sealing is a polypropylene container etc., good heat sealing and easy opening can not be performed, and there are restrictions of applications such as inability to use for boil and retort applications, and a package There were restrictions in the configuration design of the

JP-A-57-131556 Unexamined-Japanese-Patent No. 5-212835

In the process of attempting to develop an easy-peel sealant film in view of the prior art, the inventor of the present invention is composed of at least two layers of a base layer and a seal layer, and polypropylene and low density manufactured using a metallocene catalyst for the seal layer. When using the resin composition which consists of polyethylene, it discovered that smooth easy peel was attained.
However, in the resin composition composed of polypropylene and low density polyethylene manufactured using a metallocene catalyst, the heat seal temperature range for expressing good easy peelability is low, for example, cohesive failure at a heat seal temperature of about 140 ° C to 170 ° C. Although stable peeling is obtained, it is not stable in the temperature range exceeding 180 ° C., and the strength (peel strength, opening strength) required for peeling becomes high, and there is room for further improvement such as deterioration of the peel appearance. It was found.

  Therefore, an object of the present invention is an easy peel sealant film having good peel appearance and stable peel strength even in a heat seal temperature range of 180 ° C. or higher, at least in a coextruded film comprising two layers of a base layer and a seal layer. To provide.

  Further, other objects of the present invention will become clear by the following description.

The said subject is a co-extrusion laminated film which has a base material layer and a sealing layer at least,
The base material layer is composed of a resin composition containing at least one selected from low density polyethylene, medium density polyethylene or high density polyethylene, or polypropylene,
The sealing layer is composed of a resin composition comprising 60 to 90% by mass of polypropylene and 40 to 10% by mass of low density polyethylene.
The polypropylene is made of polypropylene (m-PP) produced using 20-80 wt% of metallocene catalyst and polypropylene (z-PP) produced using 80-20 wt% of Ziegler-Natta catalyst. It is solved by the easy-peelable sealant film characterized by becoming.

  According to the present invention, it is possible to obtain an easy peel sealant film which can be peeled with a stable peel strength even in a heat seal temperature range of 180 ° C. or more, and which has a good peel appearance. Therefore, even when the object of the heat seal is made of polypropylene, stable heat sealability and easy peelability can be obtained.

  Further, in the present invention, even when the sealing area of the flange portion of the plastic molded container is small, even if the lid material is heat-sealed by the ring seal, the sealing property is not unstable and extremely good sealing property is obtained. It has a stable sealing performance even after boiling and retorting.

  Furthermore, in the present invention, the coextrusion laminating processability is excellent by using mutually compatible resins such as polyethylene or polypropylene as a material constituting the base material layer and the seal layer. Very good two-layer coextruded laminated films can be produced.

  That is, the easy peel sealant film according to the present invention is excellent in heat sealability and can fully satisfy the sealability of the package, and is required to protect the quality of the contents and extend the storage period. Since it is excellent in easy-release property while satisfying, it has easy-open property that the package can be opened easily at the time of consumption, and furthermore, it is possible to form an extremely beautiful release surface in which the occurrence of stringing and the like is prevented. The present invention can be applied to various plastic molded container lids and the like. In particular, according to the present invention, such excellent effects can be exhibited even in a wide heat seal temperature range on the high temperature side.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining this invention, (a) is an easy-peelable sealant film, (b) is a lid material, (c) shows an example of a packaged product. It is a figure explaining the other example of a lid material.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The heat sealable film may be referred to as a "sealant film" and the easy peel sealant film may be referred to as an "easy peel sealant".
Also, polypropylene resins produced using a metallocene catalyst are referred to as "m-PP" and "metallocene-polypropylene", and polypropylene resins produced using a Ziegler-Natta catalyst are referred to as "z-PP", "Ziegler- It may be described as "polypropylene".
Further, the strength required for peeling may be called "seal strength" because it is also called "peel strength" or "open strength" and is also a strength representing seal adhesion.
In addition, "having as a main component" means constituting 50% by mass or more when 100% by mass of the whole composition is constituted, preferably 70% by mass or more, more preferably 80% by mass or more More preferably, it means 90% by mass or more.

First, an example of an easy peel sealant, a lid and a package according to the present invention will be described with reference to FIG.
Fig.1 (a) is a schematic sectional drawing which shows an example of the laminated constitution of an easy-peelable sealant film. FIG.1 (b) is a schematic sectional drawing which shows an example of the laminated constitution of the lid material manufactured using the easy-peelable sealant film shown to Fig.1 (a). FIG.1 (c) is a schematic sectional drawing which shows an example of the package manufactured using the cover material shown in FIG.1 (b).

  In the present embodiment, the easy peel sealant film 1 is composed of a coextruded laminated film of at least two layers of a base material layer 11 and a seal layer 12 as shown in FIG. Is composed of a resin composition containing at least one selected from low density polyethylene, medium density polyethylene or high density polyethylene, or polypropylene, and the seal layer 12 is made of 60 to 90% by mass of polypropylene and 40 to 10 The polypropylene (PP) is composed of a mixture of 20 to 80% by weight of m-PP and 80 to 20% by weight of z-PP, and the polypropylene (PP) is composed of a resin composition of low density polyethylene. To be the basic structure.

  A lid 3 as shown in FIG. 1B can be manufactured using the above-mentioned easy peel sealant film 1. Here, the printing layer 21 is formed after forming the printing layer 21 such as characters, symbols, patterns, figures, etc. on the surface (lower side in the figure) of the substrate sheet 2 to which the corona treatment etc. have been applied. The lid 3 is manufactured by laminating the surface of the easy-peel sealant film 1 on the side of the base material layer 11 so as to face the surface of the base sheet 2.

  Moreover, the package 5 as shown in FIG.1 (c) can be manufactured using the cover material 3 mentioned above. Here, first, using the molding resin, the plastic molded container 4 is manufactured by a molding method such as injection molding method, thermoforming such as vacuum / pressure molding, or blow molding. Next, the plastic molded container 4 is filled with an article such as food and drink not shown. Next, the surface on the side of the seal layer 12 of the easy-peel sealant film 1 constituting the lid member 3 is opposed to the surface of the flange portion 41 of the plastic molded container 4 and melted and adhered by heat sealing. Thereby, the package 5 formed by sealing the opening of the plastic molded container 4 with the lid 3 can be manufactured.

  Although the example of FIG. 1 shows the case where the easy peel sealant film 1 is directly laminated on the surface of the base sheet 2 on which the printing layer 21 is formed, the present invention is not limited thereto. For example, as shown in FIG. 2, after laminating a gas barrier substrate 22 made of a resin film or the like having gas barrier properties on the surface of the substrate sheet 2 on which the printing layer 21 is formed, The peelable sealant film 1 may be laminated to form a lid 3. Alternatively, a film in which a gas barrier substrate 22 made of a gas barrier resin layer is disposed on the surface side of the easy peel sealant film 1 on the surface of the substrate layer 11 is laminated on the surface of the substrate sheet 2 on which the print layer 21 is formed. May be

  The layer configuration of the lid is not limited to the examples described above. The lid material may be laminated with other layers on one side or both sides, or between each layer according to, for example, an article to be packed and packaged, a packaging purpose, a packaging form and the like.

  In the example described above, as a lamination method for laminating at least the base sheet 2, the gas barrier base 22, the easy peel sealant film 1 and the like, for example, an adhesive layer with an adhesive for lamination is provided, A dry laminate lamination method of laminating via an adhesive layer is mentioned. Moreover, the adhesion | attachment auxiliary | assistant layer by an anchor-coat agent etc., a melt extrusion resin layer etc. are provided, and the melt extrusion lamination system etc. which are laminated | stacked via these layers are also mentioned.

The form of the plastic molded container is not limited to the examples described above. The plastic molded container can be in any form, for example, in a conical shape, a pyramid shape, a cylindrical shape, a prismatic shape such as a triangle or a square, a spherical shape, or the like according to the articles to be filled and packaged.
In addition, the seal layers 12 are made to face each other and the laminated films having the same configuration 3 as the easy peel sealant film 1 or the lid 3 are heat sealed to produce a pouch, a pouch with a bottom gusset, etc. Can.

<Base layer>
The resin constituting the base layer of the easy peel sealant film of the present invention (hereinafter sometimes referred to as the film of the present invention) is melted by heat and has compatibility with the resin constituting the seal layer, It is preferable to be excellent in coextrusion moldability, and specifically, at least one selected from low density polyethylene, medium density polyethylene or high density polyethylene, or polypropylene can be used.

The low density polyethylene has, for example, a density of 0.900 g / cm ³ or more and 0.930 g / cm
It is preferable that it is less than ³ , and it is preferable that melt flow rate (MFR) is 0.1-15.0 g / 10 minutes. Examples of low density polyethylene include homopolymers of ethylene, copolymers of ethylene and other olefins, and the like. As other olefins, for example, α-olefins such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like Etc. The carbon number of the other olefin can be, for example, 10 or less. The polymerization method is not particularly limited, and examples thereof include a high pressure method, a slurry method, a solution method, a gas phase method and the like.
In the present invention, the melt flow rate (MFR) is measured by the method according to JIS K 7210-1: 2014. The test conditions were based on JISK6922-1 and JIS K6921-1. The test temperature is polyethylene: 190 ° C, polypropylene: 230 ° C. The test load is 2160 g for both polyethylene and polypropylene. Also, the density is measured by a method in accordance with JIS K7112: 1999. The same applies below.

The medium density polyethylene preferably has, for example, a density of 0.930 g / cm ³ or more and less than 0.942 g / cm ³ , and preferably an MFR of 0.1 to 15 g / 10 min. Examples of medium density polyethylene include homopolymers of ethylene, copolymers of ethylene and other olefins, and the like. Other olefins can be selected from the alpha-olefins exemplified for low density polyethylene. The polymerization method is not particularly limited, and the method exemplified for the low density polyethylene can be used.

The high density polyethylene preferably has, for example, a density of 0.942 g / cm ³ or more, and preferably an MFR of 0.5 to 8.0 g / 10 min. Examples of high density polyethylene include homopolymers of ethylene, copolymers of ethylene and other olefins, and the like. Other olefins can be selected from the alpha-olefins exemplified for low density polyethylene. The polymerization method is not particularly limited, and the method exemplified for the low density polyethylene can be used.

Polypropylene, for example, preferably a density of less 0.890 g / cm ³ or more 0.910 g / cm ^3, it is preferable MFR is 0.5~12g / 10 min. As polypropylene, polypropylene-based resins such as homopolymers of propylene and copolymers of propylene and other olefins can be used. Other olefins are not particularly limited but include, for example, α-olefins such as ethylene. The carbon number of the other olefin can be, for example, 10 or less. The copolymer may be a block copolymer or a random copolymer.

  The polypropylene-based resin described above may be a block copolymer or a random copolymer, and is preferably a random copolymer.

  As polypropylene, it is preferable to use a polypropylene-based resin which is excellent in melt tension, stretchability, etc. and has extrusion suitability as described later. Specifically, long chain branching is introduced into the main chain of polypropylene-based resin, It is preferable to use one in which the tension in the molten state is increased.

  Specifically, as a polypropylene-based resin excellent in melt tension and stretchability, a polypropylene-based resin composed of propylene and ethylene or a block or random copolymer of propylene and 1-octene can be used.

The polypropylene resin comprising a block or random copolymer of propylene and ethylene or propylene and 1-octene as described above has, for example, a density of 0.890 g / c.
It is preferable to use one having m ^{3 to} 0.910 g / cm ³ , MFR in the range of 0.1 to 10 g / 10 min, and melt tension in the range of 100 mN or more (10 cN or more). Thereby, the film forming property of the resin composition is improved, and, for example, the upper blowing inflation film forming method can be preferably applied at the time of resin extrusion.

  Among the resins exemplified above, the resin composition constituting the substrate layer is a low density polyethylene having a MFR of 0.1 to 15 g / 10 min and / or a medium density polyethylene having a MFR of 0.1 to 15 g / 10 min. It is preferred to be configured. Thereby, the effect of the present invention is exhibited more suitably.

<Sealing layer>
The resin composition constituting the seal layer of the film of the present invention is composed of 60 to 90% by mass of polypropylene and 40 to 10% by mass of low density polyethylene. Also, the polypropylene is composed of 20 to 80% by mass of polypropylene (m-PP) manufactured using a metallocene catalyst and 80 to 20% by mass of polypropylene (z-PP) manufactured using a Ziegler-Natta catalyst Become.

  60-90: 40-10 are preferable and, as for the composition ratio (mass%) of polypropylene (PP) and low density polyethylene (LDPE), in the resin composition which comprises a sealing layer, 65-85: 35-15 are more preferable. 70 to 80:30 to 20 are more preferable.

  When the resin composition ratio of the seal layer is 60% by mass or more of polypropylene and 40% by mass or less of low density polyethylene, heat sealing is favorably performed even in a high temperature range, and seal strength, sealability and the like are improved. In particular, even in the case of face-to-face sealing, the occurrence of stringing and the like is suppressed. Further, when the content of the polypropylene is 90% by mass or less and the content of the low density polyethylene is 10% by mass or more, the easy opening property can be more suitably exhibited, and the easy opening property can be exhibited particularly in the case of face-to-face sealing. In particular, it is effective when the object of heat sealing is a molded container such as polypropylene.

  20-80: 80-20 are preferable, as for the resin composition ratio (mass%) of m-PP of the said polypropylene (PP) and z-PP, 25-75: 75-25 are more preferable, and 30-70: 70. To 30 is more preferable. By using m-PP having uniform molecular weight and composition and z-PP having high stereoregularity in such a resin composition ratio, it has excellent peel appearance in a wide heat seal temperature range on the high temperature side. Easy openability can be further improved.

  The melt flow rate (MFR) of m-PP is preferably in the range of 2.0 to 10 g / 10 min, and more preferably in the range of 4.0 to 9.0 g / 10 min. Further, the MFR of z-PP is preferably in the range of 5.0 to 30 g / 10 min, and more preferably in the range of 10 to 28 g / 10 min. This makes it possible to achieve a better peel appearance and a more stable seal strength and peel strength.

Density of m-PP and z-PP, for example, 0.890 g / cm ³ or more 0.910 g / cm ³ or less. Further, it is preferable to use one having a melt tension in the range of 100 mN or more (10 cN or more). Thereby, the film forming property of the resin composition is improved, and for example, an upper blowing inflation film forming method can be preferably applied at the time of resin extrusion.

  Examples of m-PP and z-PP include polypropylenes such as propylene homopolymers (homopolymers) similar to the polypropylene constituting the base layer described above, or copolymers (copolymers) of propylene and other olefins Resins can be used. Other olefins are not particularly limited but include, for example, α-olefins such as ethylene. The carbon number of the other olefin can be, for example, 10 or less.

  The polypropylene-based resin described above may be a block copolymer or a random copolymer, and is preferably a random copolymer.

  As polypropylene, it is preferable to use a polypropylene-based resin which is excellent in melt tension, stretchability, etc. and has extrusion suitability as described later. Specifically, long chain branching is introduced into the main chain of polypropylene-based resin, It is preferable to use one in which the tension in the molten state is increased.

  Specifically, as a polypropylene-based resin excellent in melt tension and stretchability, a polypropylene-based resin composed of propylene and ethylene or a block or random copolymer of propylene and 1-octene can be used.

Examples of the low density polyethylene used in the seal layer of the present invention include homopolymers of ethylene, copolymers of ethylene and other olefins, and the like. As other olefins, for example, α-olefins such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like Etc. The carbon number of the other olefin can be, for example, 10 or less. The polymerization method is not particularly limited, and examples thereof include a high pressure method, a slurry method, a solution method, a gas phase method and the like.
The density is preferably 0.910 g / cm ³ or more and less than 0.930 g / cm ³ , and the MFR is preferably 0.1 to 10 g / 10 min.

  The base layer and the seal layer constituting the easy-peel sealant film can contain the resin component described above for each layer as the main component of the vehicle, and other components can be appropriately blended within the range that does not impair the effects of the present invention. Other components are, for example, film processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidative property, slipperiness, mold releasability, flame retardancy, anti-mold resistance, electrical properties, strength It can be blended for the purpose of improving etc. As such other components, one or more of various plastic compounding agents, additives and the like are compounded, and further, if necessary, a solvent, a diluent and the like are added and sufficiently kneaded to make each layer The resin composition to be formed can be prepared. Specific examples of the other components are not particularly limited, but, for example, lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, flame retardants, flame retardants, foaming agents, Antifungal agents, pigments, dyes, dispersants, surfactants, antiblocking agents and the like can be mentioned. Furthermore, a modifying resin or the like may be further blended in each layer constituting the easy-peel sealant film. Moreover, when preparing the composition which comprises each layer which comprises an easy-peel sealant film, a solvent, a diluent, etc. can be added as needed, and it can knead | mix fully. In addition, a modifying resin or the like can be blended as another component. When the modifying resin is compounded, the compounding amount can be appropriately set depending on the purpose, application, etc., but is, for example, 0.01 to 40 parts by mass with respect to 100 parts by mass of the total amount of each layer of the resin composition. be able to.

  It is preferable that the above-mentioned lubricant has little migration in the resin, and as such lubricant, for example, wax, higher fatty acid or metal salt thereof, aliphatic alcohol, ester, glyceride, higher fatty acid amide, silicone oil etc. Can be mentioned. Examples of the wax include liquid paraffin, white petrolatum, petroleum wax, microcrystalline wax, montan wax, polyethylene wax and the like. Examples of the higher fatty acid or the metal salt thereof include higher fatty acid having 8 to 22 carbon atoms, or higher fatty acid aluminum, higher fatty acid calcium, higher fatty acid magnesium, higher fatty acid zinc, higher fatty acid lithium and the like. Examples of aliphatic alcohols include linear aliphatic monohydric alcohols having 8 to 18 carbon atoms, glycerin, sorbitol, propylene glycol, pentaerythritol triethylene glycol and the like. Examples of the ester include an ester of a higher fatty acid having 4 to 22 carbon atoms and a linear aliphatic monohydric alcohol having 8 to 18 carbon atoms. Further, as esters, for example, dibutyl acetyl citrate, di-2 ethyl-hexyl adipate, n-hexyl azelate, ethanediol montanic acid ester, poly (1,3-butanediol adipic acid) ester, acetyl ricinoleic acid Also included are esters of alcohols with fatty acids such as methyl, poly (1,3-butylene glycol, 1,4-butylene glycol, octyl alcohol adipate), sugar wax and the like. Examples of the glyceride include hydrogenated edible fats and oils, castor oil, spam acety wax, acetylated monoglyceride and the like. Examples of higher fatty acid amides include ethylene bis fatty acid amides represented by ethylene bis oleyl amide having 16 to 18 carbon atoms, higher fatty acid amides having 8 to 22 carbon atoms, stearyl erucamide, erucic acid amide, oleyl palmi amide Toamide etc. are mentioned. Examples of silicone oils include methylhydrogenpolysiloxane, dimethylpolysiloxane, methylphenylpolysiloxane, polyoxyalkylene dimethylpolysiloxane and the like. Further, as a lubricant, glycerin such as rosin or maleic acid-modified rosin can also be used. Among the lubricants described above, for example, erucic acid amide, ethylene bis oleyl amide, stearic acid amide, oleic acid amide, methylene bis stearic acid amide and the like are suitably used because they have excellent lubricity. The lubricant may be used alone or in combination of two or more. When the lubricant is blended, it can be blended, for example, at a ratio of 0.08 parts by mass to 10.0 parts by mass with respect to 100 parts by mass of the resin component of each layer.

As the antiblocking agent described above, for example, an inorganic compound-based antiblocking agent or an organic compound-based antiblocking agent can be used. Examples of inorganic compound-based antiblocking agents include oxides, hydroxides, carbonates, sulfates, and silicates. Examples of the oxide include aluminum oxide, magnesium oxide, silica, calcium oxide, titanium oxide, zinc oxide and the like. As a hydroxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide etc. are mentioned, for example. Examples of carbonates include magnesium carbonate and calcium carbonate. As a sulfate, calcium sulfate, barium sulfate etc. are mentioned, for example. Examples of the silicate include magnesium silicate, aluminum silicate, calcium silicate, aluminosilicate and the like. Further, as the inorganic compound based antiblocking agent, for example, kaolin, talc, diatomaceous earth, etc. can also be used. As an organic compound type antiblocking agent, for example, fine powder of high density polyethylene, ultra high molecular weight polyethylene having a molecular weight of 300000 or more, polypropylene, polycarbonate, polyamide, polyester, melamine resin, diallyl phthalate resin, acrylic resin, etc. is used be able to. The antiblocking agent may be used alone or in combination of two or more. When mix | blending an antiblocking agent, it can mix | blend in the ratio of 0.01 mass part-3 mass parts with respect to 100 mass parts of resin components of each layer, for example.

  When producing the film of the present invention, first, each resin composition for constituting the base layer and the seal layer is prepared, and then each resin composition is subjected to, for example, T-die coextrusion, inflation co-extrusion By co-extrusion using a machine etc., it is possible to produce an easy peel sealant consisting of a two-layer co-extrusion laminated film of a substrate layer and a seal layer.

  Compounding preparation of the resin composition of the seal layer may mix m-PP and z-PP in advance before mixing with low density polyethylene, or low density polyethylene, m-PP and z-PP. You may mix and use simultaneously.

  In addition, the film of the present invention is not limited to the case of two layers. The co-extrusion laminated film only needs to have at least a base material layer and a seal layer, and a multilayer film of three or more layers may be used depending on the purpose, application and the like. In the case of three or more layers, for example, one or more other resin compositions are co-extruded together with each resin composition for forming the base layer and the seal layer, and one or more other resins A co-extruded laminated film in which the composition layer is further laminated can be produced.

  Although the total thickness of the film of the present invention is not particularly limited, it can be, for example, in the range of 20 μm to 70 μm, preferably in the range of 30 μm to 50 μm.

  The layer thickness of each layer is not particularly limited, but the layer thickness of the base layer may be, for example, in the range of 17 μm to 40 μm, preferably in the range of 25 μm to 35 μm, and the layer thickness of the seal layer is 3 μm to The thickness is preferably in the range of 30 μm, and more preferably in the range of 3 μm to 15 μm.

  When the layer thickness of the substrate layer is 17 μm or more, the film formation stability is good, and when it is 40 μm or less, the material cost can be reduced, weight reduction can be achieved, and the compatibility with the environment is also enhanced. Furthermore, over-spec is avoided. When the layer thickness of the sealing layer is 3 μm or more, the fluctuation of the film forming stability is more surely prevented, the stability of the heat seal is improved, and by being 30 μm or less, the occurrence of stringing etc. is more It is reliably prevented and the peel appearance is even better.

  The base layer of the film of the present invention described above greatly contributes to the strength as a lid material, tear resistance, so-called waist. In addition, the sealing layer exerts effects such as sealing strength (peeling strength, opening strength), peeling state (beautiful of peeling surface), convenience, and the like.

  As described above, the film of the present invention is excellent in sealability and has a performance as a heat sealable resin layer excellent in easy openability, and as a heat sealable material constituting a packaging material It is preferably used.

  The film of the present invention can be optionally laminated, for example, with a substrate sheet to produce laminated materials of various forms. The type of the substrate sheet is not particularly limited, and examples thereof include plastic films, paper, barrier substrates that block permeation of oxygen gas, water vapor, etc., cellophane, woven or non-woven fabrics, glass plates, etc. It can be optionally laminated with species or two or more species. For example, the laminated material can be made into a bag to form a packaging bag or the like. Also, for example, the lid material can be configured by such a laminated material. The application of the laminated material is not limited to the packaging material, and can be applied to various applications.

  In particular, the film of the present invention is excellent in heat sealability as a heat seal material, and the sealability can be sufficiently satisfied, and quality protection of the articles to be filled, extension of the storage period, and the like can be achieved. Moreover, since it is excellent in easy openability, a packaging bag can be opened easily at the time of consumption. Furthermore, occurrence of stringing and the like can be prevented at the peeling interface, and a beautiful peeling interface can be formed, which is suitable as a lid material for various plastic molded containers.

  Next, the laminate using the film of the present invention will be described in more detail. A laminated material laminates | stacks a base material sheet (it is also only mentioned a base material) to the easy-peelable sealant film of this invention. The laminated material is suitably used as a packaging material or the like such as a packaging bag or a lid as described above.

  The laminated material can be manufactured, for example, by a dry lamination method or an extrusion lamination method. In the dry lamination method, a substrate made of a plastic film or the like can be laminated via a primer layer or an adhesive layer for lamination. In the extrusion laminating method, a substrate can be laminated by melt-extruding a resin or the like through a primer agent layer or an anchor coating agent layer or the like. The method for producing the laminated material is not limited to these, as long as the substrate can be laminated.

  The base material sheet which comprises a laminated material may be a basic raw material or auxiliary material which comprises packaging materials, such as a packaging bag and a lid material, etc. Therefore, the substrate sheet is preferably excellent in mechanical properties, physical properties, chemical properties and the like. Specifically, as the substrate sheet, for example, those excellent in strength, toughness, heat resistance, moisture resistance, pinhole resistance, puncture resistance, transparency and the like can be used.

  From the above viewpoints, the substrate sheet is preferably a resin film. Examples of the resin constituting the resin film include polyester resins, polyamide resins, polyaramid resins, polyethylene resins, polypropylene resins, polycarbonate resins, polyacetal resins, and fluorine resins.

  The resin film may be stretched uniaxially or biaxially, for example, or may not be stretched.

  Although the thickness of the resin film is not particularly limited, it is preferable to have a certain thickness from the viewpoint of improving strength, puncture resistance, rigidity and the like, and to have a certain thickness from the viewpoint of suppressing costs. . From these viewpoints, the thickness of the resin film can be, for example, 10 μm to 100 μm, preferably 12 μm to 50 μm, and more preferably 9 μm to 30 μm.

  The resin film is particularly preferably a film of a biaxially stretched polyester resin, a biaxially stretched polyamide resin, or a biaxially stretched polypropylene resin.

The substrate sheet is not limited to the above-described resin film. For example, a paper substrate may be used as the substrate sheet. By using a paper base, it is possible to impart formability, bending resistance, rigidity and the like. As the paper substrate, for example, a strongly sized exposed or unbleached paper substrate can be used. In addition, for example, a paper base such as pure white roll paper, kraft paper, paper board, processed paper, etc. can also be used.

The paper layer constituted by the paper substrate preferably has, for example, a basis weight of 80 to 600 g / m ² , and preferably 100 to 450 g / m ² .

  When a paper substrate is used, the paper substrate can be used alone as a substrate sheet. Moreover, a paper base material can be laminated | stacked with the resin film etc. which were mentioned above, and it can be set as a base material sheet.

  For example, a material having a property of shielding light such as sunlight or a property of not transmitting light such as water vapor, water, oxygen and the like can be used for the base sheet. The base sheet to which such a property is imparted may be a single base, or a composite base formed by combining a plurality of types of bases.

  For example, resin films having deposited films of inorganic oxides such as silicon oxide and aluminum oxide having gas barrier properties, low density polyethylene having barrier properties against water vapor, water, etc., medium density polyethylene, high density polyethylene, linear low density Resin film made of polyethylene, polypropylene, ethylene-propylene copolymer etc., polyvinyl alcohol having gas barrier properties, resin film made of ethylene-vinyl acetate copolymer saponified, nylon MXD 6 etc., additive for imparting light shielding property The resin film etc. which disperse | distribute in the resin can be used. The additive for imparting the light shielding property is not particularly limited, and may be, for example, a colorant such as a pigment.

  These materials can be used alone or in combination of two or more.

  The thickness of the film described above is not particularly limited, and can be, for example, 5 μm to 300 μm, preferably 10 μm to 100 μm.

  The thickness of the vapor-deposited film of the inorganic oxide described above is not particularly limited, but can be, for example, 100 Å to 2000 Å, preferably 200 Å to 1500 Å, from the viewpoint of obtaining sufficient gas barrier properties. By setting the thickness of the thin film layer to 2000 Å or less, preferably 1500 Å or less, cracks and the like can be prevented from being formed in the deposited film, gas barrier properties can be stably exhibited, and material cost can be suppressed. In addition, when the thickness of the thin film layer is 200 Å or more, preferably 100 Å or more, the gas barrier property can be suitably exhibited.

  Although the resin which comprises the resin film which supports a vapor deposition film is not particularly limited, for example, polyester, polyamide, polyolefin, polyvinyl chloride, polycarbonate, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer saponification etc. are mentioned. Be

  The inorganic oxide which comprises a vapor deposition film is not specifically limited, For example, a silicon oxide (SiOx), aluminum oxide, an indium oxide, a tin oxide, a zirconium oxide etc. are mentioned. The inorganic oxide may be a mixture of two or more such as a mixture of silicon monoxide and silicon dioxide, or a mixture of silicon oxide and aluminum oxide.

  The vapor deposition film can be formed by, for example, a vacuum evaporation method such as an ion beam method or an electron beam method, a sputtering method, or the like.

  Further, the substrate sheet is preferably a resin film having a property that the adsorption of a fragrant component and the like contained in the article to be filled and packaged is low and the aroma retention property is high, and further, no change in taste, no offensive odor and the like occur.

  Examples of the resin constituting such a resin film include polyacrylic resins, polymethacrylic resins, polyacrylonitrile resins, polymethacrylonitrile resins, polystyrene resins, polycarbonate resins, polyethylene terephthalate resins or the like. Resins obtained by copolymerization or modification of part of ethylene component and / or terephthalate component with other divalent or trivalent or higher polyhydric alcohol components or dicarboxylic acid components, polyester resins such as polyethylene naphthalate resins, polyamide resins And saponified ethylene-vinyl acetate copolymers, polyvinyl alcohol resins, polyvinyl chloride resins, polyvinylidene chloride resins and the like.

  Among these resins, for example, a saponified ethylene-vinyl acetate copolymer, a polyamide resin, a polyacrylonitrile resin, or a polyester resin can be preferably used. As a result, it is possible to impart an odor retention property and to provide a good barrier property to oxygen gas, water vapor and the like.

  Assuming that the packaging container, lid material, etc. are exposed to severe conditions physically or chemically, the packaging material is required to have high packaging aptitude, deformation resistance, drop impact strength, pinhole resistance, Various conditions such as heat resistance, sealability, quality maintenance, workability, and hygiene are required. Therefore, it is preferable to select and use materials that satisfy the conditions as described above.

  From such a point of view, the material is, for example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene -Ethyl acrylate copolymer, ethylene-acrylic acid or methacrylic acid copolymer, methylpentene polymer, polybutene resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinylidene chloride resin, vinyl chloride-vinylidene chloride Copolymer, poly (meth) acrylic resin, polyacrylonitrile resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyester resin Resin, polyamide type Fat, polycarbonate resins, polyvinyl alcohol resins, ethylene - saponified vinyl acetate copolymer, fluorine resin, diene resin, polyacetal resin, polyurethane resin, be selected from nitrocellulose preferred. The resin film can be composed of one or more selected materials.

  Further, for example, a film such as cellophane, a synthetic paper or the like can be used as the substrate sheet.

  The film such as the resin film may be any of extrusion film formation, inflation film formation, coating film and the like.

  An optional printing layer can be provided on the front surface, the back surface, or both surfaces of any of the layers constituting the above-described laminated material.

  The print layer is provided, for example, on the base film. In this case, a printing pattern which consists of a character, a figure, a symbol, a pattern, etc. can be printed on a substrate film, for example, and a printing layer can be formed.

The print layer can be formed by the ink composition. The ink composition can have, as a main component, an ink vehicle comprising, for example, one or more resins and the like. The ink composition may contain a colorant such as a dye or a pigment. In addition, if necessary, one or more of additives such as plasticizer, stabilizer, antioxidant, light stabilizer, ultraviolet absorber, curing agent, crosslinking agent, lubricant, antistatic agent, filler, etc. Can be blended. In addition, the ink composition can be sufficiently kneaded and prepared by blending a solvent, a diluent and the like. The printing method is not particularly limited, and examples thereof include gravure printing, offset printing, letterpress printing, screen printing, transfer printing, flexographic printing, and the like.

  The vehicle for ink is not particularly limited, and, for example, linseed oil, cut oil, soybean oil, hydrocarbon oil, rosin, rosin ester, rosin ester, rosin modified resin, shellac, alkyd resin, phenolic resin, maleic acid resin, natural resin, Hydrocarbon resin, polyvinyl chloride resin, polyvinyl acetate resin, polystyrene resin, polyvinyl butyral resin, acrylic or methacrylic resin, polyamide resin, polyester resin, polyurethane resin, epoxy resin, urea resin, melamine One or more selected from resins, amino alkyd resins, phenol resins, nitrocellulose, ethyl cellulose, chlorinated rubber, cyclized rubber and the like can be used.

  The laminating adhesive layer that can be provided on the above-described laminated material can be formed by the laminating adhesive. Examples of adhesives for lamination include polyvinyl acetate adhesives, homopolymers such as ethyl, butyl and 2-ethylhexyl esters of acrylic acid, or copolymers of these with methyl methacrylate, acrylonitrile, styrene and the like. Adhesive based on polyacrylate, cyanoacrylate based adhesive, ethylene copolymer based adhesive based on copolymer of ethylene and vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid and other monomers, cellulose based adhesive Resin, polyester adhesive, polyamide adhesive, polyimide adhesive, amino resin adhesive consisting of urea resin or melamine resin, phenol resin adhesive, epoxy adhesive, polyurethane adhesive, reactive type ( Meta) acrylic adhesive, chloroprene rubber, nitrile rubber Styrene - butadiene made of rubber or the like rubber adhesive, a silicone-based adhesive, an alkali metal silicate, inorganic adhesive or the like made of a low-melting glass.

  The composition system of the adhesive may be any composition form such as aqueous type, solution type, emulsion type and dispersion type. The adhesive may be in any form such as a film, sheet, powder or solid. Furthermore, the adhesion mechanism of the adhesive may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a heat pressure type, and the like.

The adhesive can be applied, for example, by a coating method such as a roll coating method, a gravure roll coating method or a kiss coating method, or a printing method. The coating amount of the adhesive can be, for example, 0.1 to 10 g / m ² in a dry state.

  The anchor coating agent layer that can be provided on the above-described laminate can be formed by an anchor coating agent. As an anchor coat agent, organic titanium type, such as an alkyl titanate, an isocyanate type, a polyethylene imine type, a polybutadiene type, etc. are mentioned, for example. The anchor coating agent may be either aqueous or oily.

The anchor coating agent can be applied, for example, using a coating method such as roll coating, gravure roll coating, or kiss coating. The coating amount of the anchor coating agent can be, for example, 0.1 to 5 g / m ^{2 in} a dry state.

Examples of the resin constituting the melt-extruded resin layer in the extrusion lamination method described above include polyethylene resins, polypropylene resins, acid-modified polyethylene resins, acid-modified polypropylene resins, ethylene-acrylic acid or methacrylic acid copolymers Selected from thermoplastic resins such as surlyn resin, ethylene-vinyl acetate copolymer, polyvinyl acetate resin, ethylene-acrylic acid ester or methacrylic acid ester copolymer, polystyrene resin, polyvinyl chloride resin and the like 1 type or 2 types or more can be used.

  In the extrusion laminating method, in order to obtain stronger adhesive strength, for example, it can be laminated via an anchor coating agent layer such as the above-mentioned anchor coating agent.

  The primer layer mentioned above is, for example, polyurethane resin, polyester resin, polyamide resin, epoxy resin, phenol resin, (meth) acrylic resin, polyvinyl acetate resin, polyolefin resin such as polyethylene or polypropylene. Alternatively, it can be formed of a resin composition (primer coating agent) containing the copolymer, modified resin, cellulose resin, etc. as the main component of the vehicle.

The primer coating agent can be applied, for example, using a coating method such as roll coating, gravure roll coating, or kiss coating. The coating amount of the primer coating agent can be, for example, 0.1 to 10 g / m ² in a dry state.

  When the above-described lamination is performed, the film may be subjected to pretreatment such as corona treatment and ozone treatment, if necessary.

  Next, a method for producing a packaging bag by using a laminated material will be described. When making a bag, make a packaging bag by folding it so that the sides of the easy peel sealant forming the inner layer of the laminated material face each other and heat-sealing the peripheral end to form a sealed portion. Can. Alternatively, a packaging bag is manufactured by laminating two laminated materials so that the surfaces of the easy peel sealant forming the inner layer of the laminated material face each other, and heat sealing the peripheral end portions to form a sealed portion. You can bag it.

  For heat sealing of the peripheral end, for example, side seal type, two-way seal type, three-way seal type, four-way seal type, envelope sticking seal type, combined palm sticking seal type (pillow seal type), pleated seal type, flat bottom seal A form such as a mold or a square bottom seal can be used.

  In addition, for example, a self-standing packaging bag (standing pouch) or the like can be manufactured using the laminated material. Furthermore, a tube container etc. can also be manufactured using a laminated material.

  As a heat sealing method, for example, a bar seal, a rotating roll seal, a belt seal, an impulse seal, a high frequency seal, an ultrasonic seal, etc. can be used.

  The packaging bag may be provided, for example, with a spout such as a one-piece type, a two-piece type, or a zipper for opening and closing as required.

  When the packaging container is a liquid-filled paper container including a paper base, first, a laminated material in which the paper base is laminated is manufactured as a lamination material. Then, a blank board for producing a paper container is produced by the laminated material. The blank plate can then be used to box the barrel, bottom, head, etc. to produce a liquid filled paper container. The liquid paper container may be, for example, a brick type, a flat type, a goebel top type, and the like.

  The laminated material can also be used, for example, as a lid for sealing the opening of a plastic molded container.

  Examples of the resin constituting the plastic molding container include polyethylene resin, polypropylene resin, ethylene-propylene copolymer, polyacrylic resin or polymethyl methacrylic resin, polyvinyl chloride resin, vinyl chloride-vinylidene chloride co-weight Combined, polyacrylonitrile resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyester resin, polyamide resin, polycarbonate resin, A fluorine resin, a diene resin, a polyacetal resin, a polyurethane resin, nitrocellulose, etc. are mentioned. Such a resin is molded by, for example, a molding process such as extrusion molding, injection molding, blow molding, foam molding, thermoforming such as vacuum and pressure, cast molding, and compression molding to produce a plastic molded container. be able to.

  For example, a bar seal, a rotating roll seal, a belt seal, an impulse seal, a high frequency seal, an ultrasonic seal or the like can be used as a method of heat sealing the lid material and the plastic-made container.

  Examples of articles filled and packaged in a plastic molded container include various food and drink, chemicals such as adhesives and adhesives, cosmetics, cosmetics, detergents, medicines, and general goods such as chemical giro.

  The packaging bag manufactured as described above includes, for example, food and drink, fruit juice, juice, drinking water, liquor, cooked food, fish paste product, frozen food, meat product, simmered food, salmon, liquid soup, seasoning, etc. And other various food and drink products, chemical products such as adhesives, adhesives, liquid detergents and the like, cosmetics, medicines, general goods such as chemical cairo and articles such as photosensitive materials, etc. can be filled and packaged.

  The self-supporting bag can be used, for example, for filling and packaging liquid food and drink, food and drink containing water and the like. As specific examples, for example, a self-supporting bag for filling and packaging soy sauce, sauce, soup etc., a self-supporting bag for filling and packaging fresh confectionery etc., a packaging bag for filling and packaging frozen food, or boiled food or retort food etc. And self-supporting bags for packing and packaging.

  For example, an opening of the manufactured self-supporting bag is filled with an article such as food and drink, and then the opening is heat-sealed to form a seal, and further, if necessary, for example, boiling treatment , Retort treatment, etc. to produce a packaged product.

  Self-supporting bags can also be used, for example, in applications for filling and packaging industrial materials. Industrial materials include, for example, articles such as films, photosensitive materials such as photosensitizers, and the like.

  The film of the present invention is excellent in heat sealability as a heat seal material, and can sufficiently satisfy the sealability. In addition, requirements such as protection of the quality of the articles to be filled and extension of the storage period can be suitably met. Furthermore, it is excellent in easy-openability, and it has easy-openability which can open easily a lid material or a packaging bag at the time of consumption. Furthermore, threading and the like at the peeling interface can be prevented, and a beautiful peeling interface can be formed. According to the present invention, these effects can be exhibited over a wide heat seal temperature range on the high temperature region side.

  A resin composition comprising m-PP, z-PP, and low density polyethylene can cope with a wide heat seal temperature range, so it is highly versatile for various uses for forming a heat seal as a heat seal resin composition. Used.

  Examples of the present invention will be described below, but the present invention is not limited by these examples.

Example 1
1. Preparation of Resin Composition First, resin compositions for a base layer and a seal layer for constituting an easy peelable sealant film were prepared as follows.

[Resin composition for base layer]
A low density polyethylene-α-olefin copolymer (density = 0.923 g / cm ³ , MFR = 1.5 g / 10 min) was used.

[Resin composition for seal layer]
55% by mass of polypropylene (m-PP, density = 0.900 g / cm ³ , MFR = 7.0 g / 10 min) prepared using a metallocene catalyst and polypropylene (z-PP prepared using a Ziegler-Natta catalyst , Density = 0.900 g / cm ³ , MFR = 20 g / 10 min) and low density polyethylene (LDPE, density = 0.924 g / cm ³ , melt flow rate, MFR = 0.7 g / 10 min) The resin composition for the seal layer was obtained by sufficiently kneading 25% by mass.

Here, the composition ratio (% by mass) of PP and LDPE constituting the seal layer is 75:25.
Moreover, polypropylene (PP) is a composition ratio (mass%) 73:27 of m-PP and z-PP.

2. Preparation of Easy-Peelable Sealant Film Each resin composition prepared above was co-extruded into a base layer of 25 μm and a seal layer of 5 μm using a two-layer, two-layer, top-blowing, air-cooling inflation co-extrusion film forming machine The film was formed to obtain an easy peel sealant film consisting of a coextruded inflation film with a total thickness of 30 μm. The total thickness and layer thickness are values measured by Mitsutoyo "sickness gauge".

3. Preparation of Lid A two-component curing adhesive for polyurethane-based lamination (main component: polyester polyol, curing agent: aliphatic isocyanate) is applied to the corona-treated surface of a 12 μm-thick biaxially stretched polyethylene terephthalate film by gravure roll coating To form a 3.0 g / m ² (dry state) laminating adhesive layer. Then, a 12 μm-thick biaxially stretched polyethylene terephthalate film was laminated on the surface of the laminating adhesive layer with the corona-treated surface facing each other, and both were dry laminated. Next, the other corona-treated surface of the two biaxially stretched polyethylene terephthalate films dry-laminated as described above is coated with a two-component curing adhesive for polyurethane-based laminating in the same manner as above, and the thickness is 3. An adhesive layer for lamination of 0 g / m ² (dry state) was formed. Next, the surface (corona-treated) of the base layer of the easy peel sealant obtained above was made to face the surface of the adhesive layer for lamination, overlaid, and dry laminated to obtain a lid material.

4. Preparation of Package A cup-shaped molded container made of polypropylene is filled with water, and then the seal layer of the lid obtained as described above is superposed on the surface of the flange portion of the opening to make the seal width Heat sealed at 5 mm to obtain a package. At this time, the heat seal temperature was set to 120 ° C., 130 ° C., 140 ° C., 150 ° C., 160 ° C., 180 ° C. and 200 ° C., respectively. The pressure during heat sealing was set to 0.2 MPa and the time was set to 1 second.
In the produced package, leakage of contents, breakage of lid material and the like were not observed.

(Example 2)
The same procedure as in Example 1 was repeated except that the resin composition for the seal layer was changed to the following.
In the produced package, leakage of contents, breakage of lid material and the like were not observed.
[Resin composition for seal layer]
m-PP (density ^{= 0.900g / cm 3, MFR =} 7.0g / 10 min) and 37.5 wt%, z-PP (density ^{= 0.900g / cm 3, MFR =} 20g / 10 min) 37 .5% by mass and 25% by mass of LDPE (density = 0.924 g / cm ³ , MFR = 0.7 g / 10 min) were sufficiently kneaded to obtain a resin composition for a seal layer.

Here, the composition ratio (% by mass) of PP and LDPE constituting the seal layer is 75:25.
Moreover, PP is 50:50 of composition ratio (mass%) of m-PP and z-PP.

(Example 3)
The same procedure as in Example 1 was repeated except that the resin composition for the seal layer was changed to the following.
In the produced package, leakage of contents, breakage of lid material and the like were not observed.
[Resin composition for seal layer]
25 mass% of m-PP (density = 0.900 g / cm ³ , MFR = 7.0 g / 10 min) and 50 mass% of z-PP (density = 0.900 g / cm ³ , MFR = 20 g / 10 min) And 25% by mass of LDPE (density = 0. 924 g / cm ³ , MFR = 0.7 g / 10 min) were sufficiently kneaded to obtain a resin composition for a seal layer.

  Here, the composition ratio (% by mass) of PP and LDPE constituting the seal layer is 75:25. Moreover, PP is a composition ratio (mass%) 33:67 of m-PP and z-PP.

(Example 4)
The same procedure as in Example 1 was repeated except that the resin composition for the seal layer was changed to the following.
In the produced package, leakage of contents, breakage of lid material and the like were not observed.
[Resin composition for seal layer]
m-PP (density ^{= 0.900g / cm 3, MFR =} 7.0g / 10 min) and 37.5 wt%, z-PP (density ^{= 0.900g / cm 3, MFR =} 26g / 10 min) 37 .5% by mass and 25% by mass of LDPE (density = 0.924 g / cm ³ , MFR = 0.7 g / 10 min) were sufficiently kneaded to obtain a resin composition for a seal layer.

  Here, the composition ratio (% by mass) of PP and LDPE constituting the seal layer is 75:25. Moreover, PP is 50:50 of composition ratio (mass%) of m-PP and z-PP.

(Comparative example 1)
The same procedure as in Example 1 was repeated except that the resin composition for the seal layer was changed to the following.
In the produced package, leakage of contents, breakage of lid material and the like were not observed.
[Resin composition for seal layer]
m-PP (density ^{= 0.900g / cm 3, MFR =} 7.0g / 10 min) 75 wt% and, LDPE (density ^{= 0.924g / cm 3, MFR =} 0.7g / 10 min) 25 wt% Were sufficiently kneaded to obtain a resin composition for a seal layer.

(Comparative example 2)
The same procedure as in Example 1 was repeated except that the resin composition for the seal layer was changed to the following.
In the produced package, leakage of contents, breakage of lid material and the like were not observed.
[Resin composition for seal layer]
m-PP (density ^{= 0.900g / cm 3, MFR =} 7.0g / 10 min) 75 wt% and, LDPE (density ^{= 0.920g / cm 3, MFR =} 0.3g / 10 min) 25 wt% Were sufficiently kneaded to obtain a resin composition for a seal layer.

<Measurement and evaluation method>
The following physical properties were measured or evaluated for the films manufactured in Examples 1 to 4 and Comparative Examples 1 to 2 and the lids and packages manufactured using the films.
(1) Measurement of Layer Thickness of Sealing Layer The layer thickness of each of the sealing layers in Examples 1 to 4 and Comparative Examples 1 and 2 was 5 μm.

(2) Measurement of peel strength For a package heat sealed at a seal width of 5 mm, the peel strength (open strength, seal strength, unit: N) at the time of peeling the lid from the flange and opening is 300 mm. It measured on the conditions of / min, and the result was shown in Table 1.

(3) Evaluation of Peeling Appearance The appearance of the peeling surface after peeling the lid from the package was evaluated in three stages based on the following evaluation criteria, and the results are shown in Table 1.
〔Evaluation criteria〕
○: A beautiful peeling mark remains Δ: A peeling mark remains but is insufficient ×: A peeling mark does not remain or filming (stringing) is caused and the appearance is poor

<Evaluation>
From Table 1, Examples 1 to 4 have excellent easy openability and the like in a wide heat seal temperature range, and in particular, the peel appearance is good even in a temperature range of 180 ° C. or more at the heat seal temperature, and stable peel strength (open It can be seen that the strength, seal strength) is achieved. On the other hand, Comparative Examples 1 and 2 have insufficient easy peelability in the heat seal test at high temperature, specifically, in the case of heat seal at 180 ° C. or higher, the peel appearance is not beautiful and the heat at 200 ° C. Peeling strength was excessive in the seal.

The easy-peel sealant film according to the present invention is a heat seal material which is excellent in heat sealability and can sufficiently satisfy the sealability, and aims at quality protection of a filled article, extension of storage period, etc. be able to. In addition, the packaging bag can be easily opened at the time of consumption because it is excellent in easy opening property, and further, the occurrence of stringing and the like on the peeling surface can be prevented and a beautiful peeling surface can be formed. It can apply as a lid material etc. for plastic molding containers.
In particular, when the heat seal target is a polypropylene container, the heat seal setting temperature range in which good heat sealability and easy peelability can be obtained is wide, so even if the heat seal manufacturing conditions have fluctuations or fluctuations, Availability is high in that the package can be stably produced. Moreover, since it can respond also to a boiling and retort process, it can utilize for various content packaging.

1: Easy peel sealant 11: base layer 12: seal layer 2: base sheet 21: printed layer 3: lid 4: plastic molded container 41: flange 5: packaged product 22: gas barrier base layer

Claims (5)

A coextruded laminated film having at least a substrate layer and a sealing layer,
The base material layer is composed of a resin composition containing at least one selected from low density polyethylene, medium density polyethylene or high density polyethylene, or polypropylene,
The sealing layer is composed of a resin composition comprising 60 to 90% by mass of polypropylene and 40 to 10% by mass of low density polyethylene.
The propylene is composed of polypropylene (m-PP) produced using 20-80 wt% of metallocene catalyst and polypropylene (z-PP) produced using 80-20 wt% of Ziegler-Natta catalyst. Easy peel sealant film characterized by becoming.   The melt flow rate (MFR) of the m-PP is 2.0 to 10 g / 10 min, and the melt flow rate (MFR) of the z-PP is 5.0 to 30 g / 10 min. Easy peel sealant film.   The easy-peelable sealant film according to claim 1 or 2, wherein the layer thickness of the seal layer is 3 μm to 30 μm.   The package comprised using the easy-peelable sealant film in any one of Claims 1-3. A package formed by sealing the easy peel sealant film according to any one of claims 1 to 3 and the polypropylene resin layer of a container in a corresponding manner.

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