JP2020083345A - Laminated film for packaging material, packaging material and package - Google Patents

Abstract

To provide a laminated film for a packaging material dispensing with an adhesive resin layer while keeping mechanical strength, a packaging material allowing easy breakage of a bag using the laminated film for the packaging material, and a package using therewith.SOLUTION: A laminated film 1 for a packaging material comprises at least three layers, and has: a front surface layer 2 having an olefin-based thermoplastic resin as a main material; an intermediate layer 3 formed on one face side of the front surface layer 2 and having a polyolefin-based resin blended with a compatibilizer as the main material; and a rear surface layer 4 formed on a face opposite to the surface layer 2 of the intermediate layer 3 and having a polyamide resin as the main material. The compatibilizer is a thermoplastic resin comprising a molecular structure having a reactive group reacting with the polyamide resin. The polyamide resin of the rear surface layer 4 has a thickness of 50 μm or more and 125 μm or less. An addition amount of the compatibilizer is 10 mass% or more and 30 mass% or less of the mass of the polyolefin-based resin.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminated film for packaging material, a packaging material, and a package.

The packaging material is used, for example, in a packaging bag for packaging foods, medical products, and the like. The contents of the packaging bag have various states such as liquid, powder, paste, and solid. As a film used for such a packaging material for a packaging bag, a film of polyethylene, polypropylene, an ethylene-vinyl acetate copolymer, an ethylene-vinyl alcohol copolymer, a polyamide, a polyester or the like is generally used.
Physical properties required for packaging materials include suitability for filling the contents, no damage to the bag when external force is applied to the packaging materials, openability when opening the packaging materials, transparency of visible contents, etc. It is required to have good physical properties and productivity during manufacturing.

Regarding the mechanical strength such as the fact that the bag is not damaged when an external force is applied to the packaging material as described above, a laminate film for packaging material is laminated with a base material excellent in barrier property and mechanical strength. As a result, strength as a packaging material may be imparted. However, the use of an adhesive used for lamination increases the packaging material manufacturing process, which leads to problems such as product stability, reduced production efficiency, and environmental load.
In order to solve these problems, for example, in addition to polyolefin resins such as polyethylene and polypropylene, coextrusion of a plurality of resins with different properties such as polyamide resins such as nylon (registered trademark) makes the film multifunctional. The method of giving is used. For example, Patent Document 1 discloses a multilayer film which has a polyamide resin layer, an olefin resin layer, and a rubber elastic layer therebetween and is characterized by low warpage by an inflation method.

JP, 2013-002893, A

However, in the method of Patent Document 1, in order to facilitate mutual adhesion when laminating a large number of types of resins or resins having different properties, for example, an adhesive layer made of an adhesive resin is provided between the intermediate layer and the back surface layer. The film is multi-layered. Therefore, in the method of Patent Document 1, the extruder structure becomes complicated, the number of material types used increases, and manufacturing control becomes difficult.
In particular, when laminating a polyamide-based resin, which is said to have excellent mechanical strength and high barrier properties, with a polyolefin-based resin having good low-temperature heat-sealing properties, the adhesiveness between the two is low, so an adhesive resin is used between the layers. It is generally used. For this reason, it is difficult to maintain stable quality control due to multi-layering accompanying functionalization.

The present invention provides a laminated film for packaging material in which an adhesive resin layer is eliminated while maintaining mechanical strength, and a packaging material using the laminated film for packaging material with good bag breaking property, and a packaged body using the same. The purpose is to provide.

In order to solve the problems, one embodiment of the present invention is a laminated film for packaging material consisting of at least three layers, a first layer containing an olefinic thermoplastic resin as a main material, and one surface of the first layer. Formed on the side, the second layer mainly composed of a polyolefin resin blended with a compatibilizer, and the second layer is formed on the surface opposite to the first layer, the main material is a polyamide resin And a third layer, wherein the compatibilizer is a thermoplastic resin whose main material is a molecular structure provided with a reactive group capable of reacting with the polyamide resin, and the third layer has a thickness of It is 50 μm or more and 125 μm or less, and the gist of the second layer is that the addition amount of the compatibilizing agent is 10% by mass or more and 30% by mass or less of the mass of the polyolefin resin forming the second layer. .

Further, the gist is a packaging material in which at least a base material is laminated on the third layer of the laminated film for packaging material according to the one aspect, and a packaging body using the packaging material.

According to the aspect of the present invention, since the back surface layer containing a polyamide-based resin as a main material is laminated with a thickness of 50 μm or more and 125 μm or less, good mechanical strength can be imparted to the film. Furthermore, in an aspect of the present invention, by providing a second layer containing a polyolefin resin as a main material in which an additive having a reactive group capable of reacting with a polyamide resin is mixed, a low temperature heat seal property and an impact resistance can be obtained. By adopting a structure in which an adhesive resin layer is not provided between the good first layer and the third layer, the number of layers is reduced, the physical properties required as a packaging material are secured, and stable manufacturing control and It is possible to connect to quality control.

It is a schematic sectional drawing of the laminated film for packaging materials which concerns on embodiment based on this invention. It is sectional drawing of the standing pouch using the packaging material which concerns on embodiment based on this invention. It is a development view of a standing pouch using a packaging material concerning an embodiment based on the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, each drawing is a schematic diagram. Further, each of the embodiments described below exemplifies a configuration for embodying the technical idea of the present invention, and the technical idea of the present invention is that the material, shape, structure, etc. of the components are as follows. Not specific to a thing.

The laminated film for packaging material 1 of the present embodiment comprises at least three layers, and as shown in FIG. 1, a surface layer 2 constituting a first layer, an intermediate layer 3 constituting a second layer, and a third layer. And the back surface layer 4 constituting the.
The surface layer 2 constituting the first layer has an olefinic thermoplastic resin as a main material. As the olefin-based thermoplastic resin, for example, a low-density olefin-based resin which is a thermoplastic resin specialized for heat sealing properties is preferable.
The intermediate layer 3 that constitutes the second layer is mainly composed of a polyolefin resin in which a compatibilizing agent having a molecular structure having a reactive group capable of reacting with a polyamide resin is added (added).
The back surface layer 4 constituting the third layer has a thickness of 50 μm or more and 125 μm or less and is mainly made of polyamide resin.
In this specification, the main material means 90% by mass or more, preferably 95% by mass or more of the corresponding layer.

<Surface layer>
As the main material of the surface layer 2, a material capable of being formed into a film by an extruder capable of heating up to more than 300° C. is preferable, and a general thermoplastic resin can be used. However, the surface layer 2 needs to have appropriate flexibility and good processability in order to be suitably used as a packaging material. From this, as the main material of the surface layer 2, low density polyethylene (LDPE) based on olefin, linear low density polyethylene (LLDPE) obtained by copolymerizing α-olefin and ethylene, medium density polyethylene (MDPE) ), high-density polyethylene (HDPE) and polypropylene and cycloolefin polymers having homopolymers, random copolymers, block copolymers, etc., cycloolefin copolymers obtained by copolymerizing cycloolefin and olefin, and obtained by copolymerizing the above olefin and vinyl acetate. Ethylene-vinyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer (EBA), ethylene obtained by modifying the side chain of ethylene vinyl acetate copolymer and olefin -It is preferable to select a single substance or a plurality of methacrylic acid copolymers (EMAA) and the like and use them appropriately.

The surface layer 2 is a required property of the sealant film for packaging materials, suitability for filling contents, no damage to the bag when external force is applied to the packaging material, and openability for opening the packaging material. Etc. must be satisfied. Specifically, it may have a melting point and a heat of fusion necessary for processing into a bag when used as a sealant film alone or laminated appropriately with a film such as polyethylene terephthalate or polyamide such as 6 nylon and 66 nylon. is important.
For the above-mentioned required characteristics, as the main material of the surface layer 2, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) obtained by copolymerizing α-olefin and ethylene, medium density polyethylene (MDPE), It is preferable to use a polyolefin resin, such as a polypropylene resin having a homopolymer, a random copolymer, a block copolymer, or the like, alone or in combination.
Further, the mechanical strength can be maintained by applying the surface layer 2 mainly composed of a low-density polyolefin resin specialized for low-temperature heat sealability to the laminated film 1 for packaging material.

<Back layer>
The polyamide resin of the back surface layer 4 is made of, for example, a polyamide thermoplastic resin. The polyamide-based thermoplastic resin is generally known as a general-purpose resin having high strength and high heat resistance, and any publicly-known layer can be used as a layer included in the laminated film for packaging material. Specifically, examples of the polyamide-based thermoplastic resin for the back surface layer 4 include mainly copolymer nylon such as polyamide 6 (PA6) and polyamide 6.66.
The thickness of the back surface layer 4 is preferably 50 μm or more and 125 μm or less. As the polyamide-based resin forming the back surface layer 4, for example, a non-stretched nylon resin can be applied and has high elasticity and excellent pinhole resistance, but in this case, the thickness of the back surface layer 4 is less than 50 μm. If it is thin, the function may not be exhibited. If the thickness of the back surface layer 4 exceeds 125 μm, the accuracy of the film-forming thickness of each layer in the laminated film 1 for packaging material may be unstable.

<Middle layer>
The polyolefin resin constituting the intermediate layer 3 is an olefin-based low density polyethylene (LDPE), a linear low density polyethylene (LLDPE) obtained by copolymerizing α-olefin and ethylene, and a medium density polyethylene (MDPE). , Polypropylene and cycloolefin polymers having high density polyethylene (HDPE) and homopolymers, random copolymers, block copolymers, etc., cycloolefin copolymers obtained by copolymerizing cycloolefins and olefins, and copolymerizations of the above olefins and vinyl acetate. Ethylene-vinyl acetate copolymer and ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer (EBA), ethylene-obtained by modifying side chains of olefin. Among methacrylic acid copolymers (EMAA) and the like, it is possible to select a single substance or a plurality of substances and use them appropriately.

The compatibilizing agent added to the polyolefin resin forming the intermediate layer 3 is preferably a thermoplastic resin having a molecular structure to which a reactive group capable of reacting with the polyamide resin is added.
As the compatibilizer, a generally known one can be used, and a double bond (C) which forms a hydrogen bond with an amide group in a resin structure, such as ethylene-vinyl acetate copolymer (EVA) and maleic anhydride modified polyethylene. Those containing ═O) are preferred.
The compounding amount of the compatibilizing agent is preferably in the range of 10% by mass or more and 30% by mass or less of the mass of the polyolefin resin forming the mid layer 3. When the blending amount is less than 10% by mass, the interlayer adhesive strength between the olefin resin of the intermediate layer 3 and the polyamide resin of the back surface layer 4 is weak, which may affect the physical properties of the laminated film for packaging material such as puncture strength. There is. On the other hand, when the amount of the compatibilizing agent is more than 30%, the density of the polyolefin resin of the mid layer 3 depends on the resin density of the compatibilizing agent and physical properties may not be maintained.

<Film properties>
The standard puncture strength of the laminated film 1 for packaging material conforms to the method described in JIS Z 1707:1997, and a tensile tester (Shimadzu Corporation AGS-500NX) was used to form a laminated film 1 for packaging material with a diameter of 1 mm. The piercing strength when a retort pouch piercing rod having a tip R of 0.5 mm is pierced at a moving speed of 200 mm/min is preferably 10 N or more, and the packaging laminated film 1 is composed only of the surface layer 2 and the intermediate layer 3. In this case, the total thickness of the packaging laminated film 1 must be increased in order to exhibit a puncture strength of 10 N or more, but by providing the surface layer 4 with a polyamide layer of 50 μm or more, the thickness of the surface layer 2 and the intermediate layer 3 can be increased. Can be suppressed to 150 μm or less. For example, if the puncture strength is less than 10 N, the frequency of pinholes in the laminated film is increased during the packaging process and distribution process, which is not preferable as a laminated film for packaging material.

In addition to the puncture strength, the laminated film for packaging material 1 is required to have physical properties such as heat sealability. In general, heat sealing properties can be improved by using a low density resin for the laminated film 1 for packaging material. Specifically, the average density of the surface layer 2, 0.900 g / cm ³ or more 0.925 g / cm ³ is preferably in a range of about. The average density of the intermediate layer, 0.900 g / cm ³ or more 0.940 g / cm ³ is preferably in a range of about.
The reason is that if it is 0.903 g/cm ³ or less, poor adhesion and flow marks will occur at the layer boundary with other layers, which is not desirable. Further, if the density is 0.938 g/cm ³ or more, the low temperature heat sealability will not be obtained when the layer thickness is thin.
The thickness of the surface layer 2 is preferably in the range of 10 μm or more and 20 μm or less. The surface layer 2 functions as an adhesive layer as a low-temperature heat-sealing layer, and thus needs to have a thickness of 10 μm or more. If it exceeds 20 μm, the rigidity may decrease, which is not preferable.
The delamination strength between the back surface layer 4 and the intermediate layer 3 is preferably 0.4 N or more. If it is less than 0.4 N, there is a fear that adhesion may be deteriorated due to floating between layers.

<Manufacturing method>
The method for producing the laminated film 1 for packaging material of the present embodiment is not particularly limited, and a known method can be used.
As a method of forming a film, an extrusion molding machine, a method of forming a film with a T die through a feed block or a multi-manifold, and a film forming method using an inflation method can be used. At this time, for example, by using a plurality of extruders and co-extruding the intermediate layer 3 between the front surface layer 2 and the rear surface layer 4, the laminated film for packaging material 1 having a layer structure of three layers or more. Can be obtained.

Regarding the cooling method of the film 1 after film formation, it can be used according to the above-mentioned film forming method. For example, in the T-die method, an air cooling method such as an air chamber, a vacuum chamber, an air knife, a water cooling method such as dipping a cooling roll into a cold water pan, or the like is not particularly limited.
When imparting a surface uneven shape by shaping, a contact portion where a pressure of 0.1 MPa or more is applied to a nip roll made of silicone rubber, NBR rubber, Teflon (registered trademark) or the like and a cooling roll made by cutting metal A method in which a molten resin is flown into and is cooled is particularly preferable.
In the laminated film for a packaging material of the present embodiment, there is no particular limitation on the use of the single film and other base materials laminated with each other and the bag-making method.
For example, a base material (not shown) may be laminated on the back surface layer 4 of the laminated film for packaging material of the present embodiment to form a packaging material.

As the base material, one that functions as a support layer of the laminated film 1 for packaging material, a film mainly made of plastic is selected, and it is appropriately selected according to usage conditions such as the type of contents and the presence or absence of heat treatment after filling. To be done. For example, polyethylene, polypropylene, polyethylene terephthalate, etc. can be applied, but not particularly limited. Furthermore, a single layer made of one of the above materials may be used, or a configuration in which a plurality of single layers of the above materials are combined and laminated is also applicable.
Even when used as a single film or laminated, the surface layer 2 serves as a content contact surface, and as shown in FIGS. 2 and 3, a standing pouch, a three-sided bag, a pouch with a palm, a gusset bag, a pouch with a spout, a pouch with a beak, etc. Can be used for.

In FIGS. 2 and 3, reference numeral 11 is a package, reference numeral 10 is a packaging material, reference numeral 12 is a standing pouch, reference numeral 13 is a pouch front surface, reference numeral 14 is a pouch back surface, reference numeral 16 is a pouring nozzle, and reference numeral 17 is an opening cut. Line of sight, reference numeral 18 is an opening knob, reference numeral 19 is a half cut line, reference numeral 20 is a bottom tape, reference numeral 21 is a ridge line of a bent portion, reference numeral 22 is a left and right side seal portion, reference numeral 23 is a bottom seal portion, and reference numeral 24 is a pouring nozzle. A seal portion, reference numeral 25 is a pouring nozzle tip seal portion, and reference numeral 26 is an embossed portion.
As described above, it is possible to appropriately carry out the surface modification treatment for improving the suitability for the post-process regardless of whether the film is laminated with a single film or another substrate. For example, it is possible to perform a surface modification treatment on the surface in contact with another substrate in order to improve the printability when using a single film and the lamination suitability when using a laminate. The surface modification treatment is preferably performed by corona discharge treatment, plasma treatment, flame treatment, or another method of expressing the characteristics of functional groups by oxidizing the film surface, or by wet process modification such as coating of an easily adhesive layer. It is possible.

Hereinafter, examples of the present invention will be described in detail, but the present invention is not limited to the following examples.

<Example 1>
The laminated film 1 for a packaging material of Example 1 is specialized in heat-sealing properties, and has a surface layer 2 made of an olefinic thermoplastic resin that does not contain a compatibilizer having a reactive group capable of reacting with nylon, and reacts with nylon. A three-layer structure of an intermediate layer 3 made of a polyolefin resin and a back layer 4 made of a polyamide resin in which a compatibilizing agent (additive, the same applies hereinafter) to which a reactive group capable of being added is mixed.
Specifically, in the surface layer 2, a linear low-density polyethylene resin (density 0.918 g/cm ³ , melt flow rate (Melt Flow Rate, MFR) 3.8) and a low-density polyethylene resin (density 0. A blend of 924 g/cm ³ and MFR 1.0) at a ratio of 95:5 was used.

In the middle layer 3, a linear low-density polyethylene resin (density 0.924 g/cm ³ , MFR 3.2) and a low-density polyethylene resin (density 0.924 g/cm ³ , MFR 1.0) were mixed at a ratio of 95:5. The one blended in was used. 10% by mass of an ethylene-vinyl acetate copolymer (EVA, density 0.960 g/cm ³ , MFR 14) was added to the mid layer 3 as a compatibilizing agent having a reactive group capable of reacting with a polyamide resin.
For the back surface layer 4, nylon 6 (density 1.13 g/cm ³ , melt volume rate (MVR) 70 cm ³ /min), which is a polyamide resin, was used.

The surface layer 2, the intermediate layer 3 and the back surface layer 4 were each melted by heating at 260° C. by a uniaxial co-extruder, and the thickness of the surface layer 2 was 15 μm and the thickness of the intermediate layer 3 was 85 μm by T die casting method. The thickness of the back surface layer 4 was 50 μm, and the laminated film 1 for packaging material having a total thickness of 150 μm was formed. For cooling, cooling was performed between a cooling roll and a roll treated with Teflon to obtain a film of the laminated sealant film 1 for packaging material.

<Example 2>
In the same production method as in Example 1, the back layer 4 had a thickness of 50 μm in the same layer structure as in Example 1, and the intermediate layer was used as a compatibilizing agent having a reactive group capable of reacting with a polyamide resin. 20% by mass of ethylene-vinyl acetate copolymer (EVA) was added to form a laminated film 1 for packaging material having a total thickness of 150 μm.

<Example 3>
In the same production method as in Example 1, the back layer 4 had a thickness of 50 μm in the same layer structure as in Example 1, and the intermediate layer was used as a compatibilizing agent having a reactive group capable of reacting with a polyamide resin. 30% by mass of ethylene-vinyl acetate copolymer (EVA) was added to form a laminated film 1 for packaging material having a total thickness of 150 μm.

<Example 4>
In the same production method as in Example 1, the back layer 4 had a thickness of 75 μm in the same layer structure as in Example 1, and the intermediate layer was a compatibilizing agent having a reactive group capable of reacting with a polyamide resin, 10% by mass of ethylene-vinyl acetate copolymer (EVA) was added to form a laminated film 1 for packaging material having a total thickness of 175 μm.

<Example 5>
In the same manufacturing method as in Example 1, the back layer 4 had a thickness of 100 μm in the same layer structure as in Example 1, and the intermediate layer had a compatibilizing agent having a reactive group capable of reacting with a polyamide resin, 10% by mass of ethylene-vinyl acetate copolymer (EVA) was added to form a laminated film 1 for packaging material having a total thickness of 200 μm.

<Example 6>
In the same production method as in Example 1, the back layer 4 had a thickness of 125 μm in the same layer structure as in Example 1, and the intermediate layer had a compatibilizing agent having a reactive group capable of reacting with a polyamide resin, 10% by mass of ethylene-vinyl acetate copolymer (EVA) was added to form a laminated film 1 for packaging material having a total thickness of 225 μm.

<Comparative Example 1>
In the same production method as in Example 1, the layer structure was the same as in Example 1 except that the back surface layer 4 had a thickness of 50 μm, and the intermediate layer was a compatibilizing agent having a reactive group capable of reacting with a polyamide resin. , Ethylene-vinyl acetate copolymer (EVA) was not added to form a laminated film 1 for packaging material having a total thickness of 150 μm.

<Comparative example 2>
In the same production method as in Example 1, the back layer 4 had a thickness of 50 μm in the same layer structure as in Example 1, and the intermediate layer was used as a compatibilizing agent having a reactive group capable of reacting with a polyamide resin. 5% by mass of ethylene-vinyl acetate copolymer (EVA) was added to form a laminated film 1 for packaging material having a total thickness of 150 μm.

<Comparative example 3>
In the same production method as in Example 1, the back layer 4 had a thickness of 25 μm in the same layer structure as in Example 1, and the intermediate layer had a compatibilizing agent having a reactive group capable of reacting with a polyamide resin, 10% by mass of ethylene-vinyl acetate copolymer (EVA) was added to form a laminated film 1 for packaging material having a total thickness of 125 μm.

<Comparative example 4>
In the same manufacturing method as in Example 1, the back surface layer 4 had a thickness of 15 μm in the same layer structure as in Example 1, and the intermediate layer had a compatibilizing agent having a reactive group capable of reacting with a polyamide resin, 10% by mass of ethylene-vinyl acetate copolymer (EVA) was added to form a laminated film 1 for packaging material having a total thickness of 115 μm.

The piercing property and heat sealing property of the laminated film 1 for packaging material obtained in each of the examples and each of the comparative examples and the interlayer adhesion between the back surface layer 4 and the intermediate layer 3 were evaluated.

(Puncture evaluation)
In the puncture strength measurement, according to JIS Z 1707:1997, a retort pouch piercing rod having a diameter of 1 mm and a tip R of 0.5 mm was moved to the laminated film 1 for packaging material by using a tensile tester (Shimadzu Corporation AGS-500NX). The puncture strength when piercing at a speed of 200 mm/min was measured.
The evaluation results were evaluated as "◯" when the puncture strength was 10 N or more, and as "x" when the puncture strength was other than that.

(Heat seal evaluation)
The heat sealability was evaluated by using a heat sealer (TP-701-B, Tester Sangyo Co., Ltd.) with a seal pressure of 0.2 MPa, a seal time of 1 second, a seal width of 10 mm, and a seal temperature of 100° C. to 10° C. intervals. The surfaces of the surface layers of the laminated film 1 for packaging material were overlapped and sealed. Cut the sealed film into a width of 15 mm x 100 mm, measure the seal strength when peeled 180° using a tensile tester (Shimadzu Corporation AGS-500NX) with a chuck distance of 50 mm and a pulling speed of 300 mm/min. did.
As a result, the lowest temperature at which the seal strength was 10 N or higher was defined as the heat-seal development temperature, the development temperature of 130° C. or lower was “◯”, and the others were “x”.

(Interlayer adhesion evaluation)
For the evaluation of the peel strength between the back surface layer 4 and the intermediate layer 3, the laminated film 1 for packaging material was cut out into a width of 15 mm×100 mm, a chuck distance was 50 mm, and a pulling speed was 300 mm/min. The 180° interlayer strength of the back surface layer 4 and the intermediate layer 3 was measured using a model number AGS-500NX).
As a result, those having a peel strength of 0.5 N or more were evaluated as “◯”, and the others were evaluated as “x”.

(Comprehensive evaluation)
As a comprehensive evaluation, all of the evaluations regarding the above-mentioned laminated film 1 for a packaging material were evaluated as “◯”, and those having at least one “x” evaluation were evaluated as “x”. Table 1 shows the evaluation results of the sealant film 1 of each of the above Examples and Comparative Examples.

From Table 1, in Examples 1 to 6, the comprehensive judgment satisfies “◯” or more. In Comparative Examples 1 and 2, the EVA addition amount was insufficient and the interlayer peeling strength between the intermediate layer 3 and the back surface layer 4 was weak, so the overall judgment was “x”. In Comparative Examples 3 and 4, the thickness of the back surface layer is insufficient, the necessary puncture strength is not obtained in the laminated film 1 for packaging material, and the thickness of the back surface layer 4 is 10% by mass even when EVA is added at 10% by mass. Since it is thin, the delamination strength is insufficient, and the overall judgment is "x". Further, in Examples 1 to 6 and Comparative Examples 1 to 4, since the heat sealability evaluations are all “◯”, the heat sealability is specialized even if the thickness of the back surface layer 4 or the EVA addition amount is changed. When the above-mentioned surface layer 2 is provided, the heat-sealing property of the laminated film for packaging material does not change.

1 Laminated film for packaging material 2 Surface layer (first layer)
3 Middle layer (second layer)
4 Back layer (third layer)

Claims (6)

A laminated film for packaging material comprising at least three layers,
A first layer containing an olefinic thermoplastic resin as a main material, a second layer formed on one side of the first layer and containing a polyolefin resin containing a compatibilizer as a main material, Formed on the surface opposite to the first layer of the two layers, comprising a third layer containing a polyamide resin as a main material,
The compatibilizer is a thermoplastic resin having a molecular structure provided with a reactive group capable of reacting with the polyamide resin,
The third layer has a thickness of 50 μm or more and 125 μm or less,
The said 2nd layer is 10 mass% or more of the mass of the polyolefin resin which comprises the said 2nd layer, and the addition amount of the said compatibilizing agent is 30 mass% or less, The laminated film for packaging materials characterized by the above-mentioned. The first layer, the average density is in the range of 0.900 g / cm ³ or more 0.925 g / cm ³ or less,
The second layer, the packaging material for a laminate film according to claim 1, wherein the average density is in the range of 0.900 g / cm ³ or more 0.940 g / cm ³ or less. 3. The packaging material according to claim 1 or 2, wherein the compatibilizer has a group or a bond having a carbonyl group [-C(=O)] that hydrogen bonds with an amide group, in the molecular structure. Laminated film. The puncture strength of the laminated film for packaging material is 10 N or more, The laminated film for packaging material according to any one of claims 1 to 3. A packaging material comprising the laminated film for packaging material according to any one of claims 1 to 4, and a base material laminated on the third layer side of the laminated film for packaging material. A package using the packaging material according to claim 5.

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