TW202112928A - Easily-adhesive polyamide film, laminating film and packing bag - Google Patents

Abstract

PROBLEM: To provide a carbon-neutral easily-adhesive polyamide film using a biomass-derived material as a raw material, that is excellent in impact resistance, bending pinhole resistance, friction pinhole resistance, and excellent water-resistant adhesive strength with a sealant film. SOLUTION: An easily-adhesive polyamide film having an adhesion modifying layer made of a polyester resin, a polyurethane resin and/or a polyacrylic resin of coating amount of 0.01 to 3 g/m 2 as a solid content on at least one side of a biaxially stretched polyamide film containing 99 to 70% by mass of polyamide 6 resin and 1 to 30% by mass of polyamide resin whose raw material is partially biomass-derived material.

Description

Easy-adhesive polyamide film, laminated film, and packaging bag

The present invention relates to a carbon neutral easily adhesive polyamide film, which is excellent in impact resistance, bending pinhole resistance and friction pinhole resistance, and has excellent water resistance to sealant film. And use raw materials derived from biomass. The easily adhesive polyamide film of the present invention can be preferably used for food packaging films and the like.

Previously, biaxially stretched films composed of aliphatic polyamides represented by polyamide 6 have excellent impact resistance and bending pinhole resistance, and have been widely used as various packaging material films.

In addition, in order to be suitable for liquid filling and packaging such as soups and seasonings, and to further improve the bending pinhole resistance and impact resistance, a biaxially stretched polyamide film is widely used, which is mixed with various elasticity in aliphatic polyamide. The body (rubber component) is further softened to improve bending pinhole resistance.

As a means for improving the above-mentioned bending pinhole resistance, a film obtained by mixing an aliphatic polyamide with a polyamide-based elastomer is known (for example, refer to Patent Document 1). The film has good bending pinhole resistance and impact resistance under low temperature environment, and it is not easy to produce pinholes due to bending fatigue under low temperature environment.

However, in addition to being generated by bending, pinholes are also generated by friction (abrasion). The improvement methods for pinholes caused by bending and pinholes caused by friction are often opposite. For example, there is a tendency that if the flexibility of the film is increased, bending pinholes are less likely to occur, but corresponding to the degree of softness, pinholes due to friction become more likely to occur. In this regard, there has been proposed a laminate for packaging that is excellent in bending resistance and rubbing resistance by providing a surface coating agent on the outer surface of the biaxially stretched polyamide film (for example, refer to Patent Document 2). However, in this method, the effect of preventing the generation of rubbing pinholes is small. In addition, a coating step becomes necessary. Furthermore, when the aliphatic polyamide is mixed with a polyamide-based elastomer film, the polyamide-based elastomer added during the film manufacture is thermally degraded, so it is easily formed at the die lip outlet. Deterioration of fat accumulation in the orifice. In addition, it is known that the deterioration will cause deterioration of the accuracy of the film thickness. In addition, there is a problem in that the deteriorated product will drop by itself and produce defective products, which will reduce the production efficiency during continuous production of the film.

In addition, when the film formed by laminating a polyamide film and a sealant film is used in a liquid soup bag or a bag for hydrated substances, the adhesive strength between the laminated films (also called lamination strength) is required high enough.

On the other hand, in recent years, in order to construct a recycling-oriented society, the use of biomass has attracted attention in the field of materials instead of raw materials for fossil fuels. Biomass is an organic compound formed by photosynthesis of carbon dioxide and water. By using this organic compound, it becomes the so-called carbon neutralization of carbon dioxide and water again (because the amount of carbon dioxide emitted and absorbed in the environment is the same, it can be suppressed as The increase in carbon dioxide, a greenhouse gas, is a raw material. Recently, the practical use of bioplastics using these biomass as raw materials has been rapidly developed, and attempts have been made to produce polyesters as general-purpose polymer materials from these biomass raw materials.

For example, in Patent Document 3, in the field of polyester films, a resin composition and a film are disclosed. The resin composition includes a polyester composed of a diol unit and a dicarboxylic acid unit, and is characterized by: The entire composition contains 50% to 95% by mass of polyester in which the diol component unit is biomass-derived ethylene glycol and the dicarboxylic acid component unit is petroleum-derived dicarboxylic acid. According to this technology, even if the polyester produced by replacing the ethylene glycol obtained from fossil fuels with the ethylene glycol derived from biomass, it can also obtain the same amount as the previous use of ethylene glycol derived from fossil fuels. The mechanical characteristics of the situation are the same. In this context, the use of carbon-neutral materials derived from biomass raw materials is also required in polyamide membranes. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 11-254615. [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-205761. [Patent Document 3] JP 2012-097163 A.

[The problem to be solved by the invention]

The present invention is created in view of the above-mentioned problems of the prior art. The purpose of the present invention is to provide a carbon-neutral, easy-adhesive biaxially stretched polyamide film, which has excellent impact resistance, bending pinhole resistance, and friction pinhole resistance, and has excellent water resistance to sealant film. , And use raw materials derived from biomass. [Means to solve the problem]

That is, the present invention includes the following configurations. [1] An easy-adhesive polyamide film having an adhesive reforming layer on at least one side of a biaxially stretched polyamide film, the biaxially stretched polyamide film containing 99% to 70% by mass of polyamide 6 resin Mass% and at least a part of the raw material is derived from 1% to 30% by mass of biomass polyamide resin, and the above-mentioned subsequent modified layer is composed of a coating amount of 0.01g/m ² to 3g/m ² in terms of solid content It is composed of any one of polyester resin, polyurethane resin, and/or polyacrylic resin. [2] An easy-adhesive polyamide film having an adhesive modification layer on at least one side of a biaxially stretched polyamide film, and the aforementioned biaxially stretched polyamide film is formed on the following substrate layer (layer A) ) Has the following functional layer (layer B) in at least a single area layer. The aforementioned subsequent modified layer is composed of polyester resin and polyamine-based ^{layer with a coating amount of 0.01 g/m 2} to 3 g/m ^{2 in terms of solid content.} It is composed of any resin of formate resin and/or polyacrylic resin. The base material layer (layer A) contains polyamide 6 resin 99% to 70% by mass and at least a part of the raw material is derived from biomass polyamide resin 1% to 30% by mass, and the functional layer (layer B) contains polyamide resin. Amide 6 resin is 70% by mass or more. [3] The easily-adhesive polyamide film described in [1] or [2] is derived from the measurement ^{of radiocarbon (C 14) with respect to all the carbon in the biaxially stretched polyamide film.} The content of biomass carbon is 1% to 15%. [4] The easy-adhesive polyamide film described in [1] or [2] is a polyamide resin in which at least a part of the raw material is derived from biomass, and is selected from polyamide 11, polyamide 410, and polyamide resin. At least one polyamide resin in the group consisting of amide 610 and polyamide 1010. [5] The easily adhesive polyamide film described in any one of [1] to [4] satisfies the following (a) and (b). (a) The number of gelbo pinhole defects when the torsion and bending test using Gelbo FLex tester is performed 1000 times at a temperature of 1°C is 10 or less; (b) In the friction resistance pinhole test, the distance until pinholes are generated is 2900 cm or more. [6] The easily adhesive polyamide film described in any one of [1] or [2] has a laminate strength of 4.0 N/15 mm or more after being bonded to a polyethylene-based sealant film. [7] A laminated film comprising a sealant film laminated with the easily-adhesive polyamide film described in any one of [1] or [2]. [8] A packaging bag using the laminated film as described in [7]. [Efficacy of invention]

The easy-adhesive polyamide film of the present invention uses polyamide 6 resin as the main component, and blends polyamide resin polymerized from raw materials derived from specific biomass, and adopts specific film forming conditions , And can be obtained to exhibit impact resistance, bending pinhole resistance, friction pinhole resistance, adhesion to the sealant film, and a carbon-neutral polyamide film. In addition, the present invention is further different from the polyamide-based elastomer previously added to improve the bending pinhole resistance. Since the polyamide-based elastomer does not deteriorate inside the mold, it can suppress the adhesion of the deterioration to the mold for a long time. The inner surface prevents grease accumulation in the orifice from adhering to the die lip exit. Thereby, it is possible to prevent the deterioration of the unevenness of the thickness of the film. In addition, if the deteriorated material adheres to the inner surface of the mold or the outlet of the die lip, the uneven thickness will deteriorate. Therefore, it is necessary to stop production and clean the die lip. The easy-adhesive polyamide film of the present invention can realize long-term continuous production. Furthermore, at least the single-area layer of the biaxially stretched polyamide film is composed of polyester resin, polyurethane resin, and/ ^{or a coating amount of 0.01 g/m 2} to 3 g/m ^{2 in terms of solid content.} Or polyacrylic resin, which is composed of any kind of resin, so that when the film laminated with the sealant film is used in the liquid soup bag or the bag for hydrated substances, the laminated film The bonding strength (also known as lamination strength) is high, so it can provide packaging bags with less breakage. In particular, the water-resistant lamination strength (lamination strength under the condition of water adhesion) is high, so even if it is used for boiling treatment or retorting treatment, it is possible to provide a packaging bag with less breakage of the bag.

Hereinafter, the easy-adhesive polyamide film of the present invention will be explained in detail. The easy-adhesive polyamide film of the present invention is characterized in that it has an adhesive reforming layer on at least one side of the biaxially stretched polyamide film, and the biaxially stretched polyamide film consists of 99% by mass of polyamide 6 resin to 70% by mass and at least a part of the raw material is composed of 1% to 30% by mass of polyamide resin derived from biomass, or from 99% to 70% by mass of polyamide 6 resin and at least part of the raw material is derived from raw materials The base layer (layer A) composed of 1% to 30% by mass of polyamide resin has at least the following functional layer (layer B) in at least one single area layer. The above-mentioned subsequent modified layer is calculated by the solid content It is composed of any one of polyester resin, polyurethane resin, and/or polyacrylic resin with a coating amount of 0.01 g/m ² to 3 g/m ^2.

[Biaxially stretched polyamide film or substrate layer (layer A)] The biaxially stretched polyamide film or substrate layer (layer A) in the present invention can obtain a biaxially stretched polyamide film composed of polyamide 6 resin by containing more than 70% by mass of polyamide 6 resin Originally it has excellent mechanical strength such as impact strength or gas barrier properties such as oxygen. The biaxially stretched polyamide film or substrate layer (layer A) in the present invention contains at least 1% to 30% by mass of the biomass-derived polyamide resin of the raw material, and the bending pinhole resistance is improved . In the case of polyamide-based elastomers or polyolefin-based elastomers, which are previously used as a modifier of bending pinhole resistance, although bending pinhole resistance is improved, rubbing pinhole resistance is deteriorated. By including 1% to 30% by mass of biomass-derived polyamide resin at least part of the raw material, a biaxially stretched polyamide film with excellent bending pinhole resistance and rubbing pinhole resistance can be obtained. In addition, it is possible to obtain a film with carbon neutrality that has little effect on the increase and decrease of carbon dioxide on the surface.

[Polyamide 6 resin] The polyamide 6 resin used in the present invention is usually produced by ring-opening polymerization of ε-caprolactam. The polyamide 6 resin obtained by ring-opening polymerization is usually used to remove the internal amide monomer with hot water, then dried, and then melt-extruded by an extruder. The relative viscosity of the polyamide 6 resin is preferably 1.8 to 4.5, more preferably 2.6 to 3.2. When the relative viscosity is less than 1.8, the impact strength of the film is insufficient. In the case of more than 4.5, the load of the extruder becomes large and it is difficult to obtain an unstretched film before stretching.

[At least a part of the raw material is derived from biomass polyamide resin] As the polyamide resin whose at least part of the raw material used in the present invention is derived from biomass, for example, polyamide 11, polyamide 410, polyamide 610, polyamide 1010, and polyamide MXD10 can be cited. Resin, polyamide 11-polyamide 6T copolymer resin, etc.

Polyamide 11 is a polyamide resin having a structure in which a monomer with 11 carbon atoms is bonded via an amide bond. Generally, polyamide 11 is obtained by using aminoundecanoic acid or undecanolide as a monomer. In particular, aminoundecanoic acid is a monomer derived from castor oil, so it is ideal from the viewpoint of carbon neutrality. The structural units derived from these monomers having 11 carbon atoms are preferably 50% or more of all structural units in the polyamide 11, more preferably 80% or more, or 100%.

The above-mentioned polyamide 11 is usually produced by polymerization of the aforementioned aminoundecanoic acid. For the polyamide 11 obtained by polymerization, the internal amide monomer is usually removed by hot water, dried, and then melt-extruded by an extruder. The relative viscosity of polyamide 11 is preferably 1.8 to 4.5, more preferably 2.4 to 3.2. When the relative viscosity is less than 1.8, the impact strength of the film is insufficient. In the case of more than 4.5, the load of the extruder becomes large and it is difficult to obtain an unstretched film before stretching.

The above-mentioned polyamide 610 is a polyamide resin having a structure in which a diamine having 6 carbon atoms and a dicarboxylic acid having 10 carbon atoms are polymerized. Usually, hexamethylene diamine and sebacic acid are used. Among them, sebacic acid is a monomer derived from castor oil, so it is preferable from the viewpoint of carbon neutrality. The total of the structural units derived from the monomers with 6 carbon atoms and the structural units derived from the monomers with 10 carbon atoms in PA610 is preferably 50% or more of all the structural units, and more preferably 80% Above, it can also be 100%.

The above-mentioned polyamide 1010 is a polyamide resin having a structure in which a diamine having 10 carbon atoms and a dicarboxylic acid having 10 carbon atoms are polymerized. Generally, polyamide 1010 uses 1,10-decanediamine (decamethylene diamine) and sebacic acid. Decamethylene diamine and sebacic acid are monomers derived from castor oil, so they are ideal from the viewpoint of carbon neutrality. The total of the structural units derived from these diamines with 10 carbon atoms and the structural units derived from dicarboxylic acids with 10 carbon atoms in PA1010 is preferably 50% or more of all structural units, and more preferably 80 Above %, it can also be 100%.

The above-mentioned polyamide 410 is a polyamide resin having a structure in which a monomer having a carbon number of 4 and a diamine having a carbon number of 10 are copolymerized. Generally, polyamide 410 uses sebacic acid and tetramethylene diamine. As sebacic acid, it is preferable to use castor oil, which is a vegetable oil, as a raw material in terms of environment. As the sebacic acid used here, from the viewpoint of environmental protection (especially the viewpoint of carbon neutrality), sebacic acid obtained from castor oil is preferable.

In the biaxially stretched polyamide film or substrate layer (layer A) in the present invention, the upper limit of the content of the polyamide resin derived from biomass at least part of the raw material is 30% by mass, more preferably 20% by mass. If the content of at least a part of the biomass-derived polyamide resin exceeds 30% by mass, when the molten film is cast, the molten film becomes unstable and it is difficult to obtain a homogeneous unstretched film.

[Auxiliary materials, additives] The biaxially stretched polyamide film or substrate layer (layer A) of the present invention may contain other thermoplastic resins, slip agents, heat stabilizers, antioxidants, antistatic agents or antifogging agents, and ultraviolet absorbers as needed. Various additives such as agents, dyes, and pigments.

[Other thermoplastic resins] In the biaxially stretched polyamide film or substrate layer (layer A) of the present invention, within the scope that does not impair the purpose of the present invention, except for the above-mentioned polyamide 6 and at least a part of the raw material is derived from the polyamide of biomass In addition to the amide resin, a thermoplastic resin may be included. Examples include: polyamide 12 resin, polyamide 66 resin, polyamide 6-polyamide 12 copolymer resin, polyamide 6-polyamide 66 copolymer resin, polyamide MXD6 resin and other polyamide series Resin. If necessary, it can also contain thermoplastic resins other than polyamide series, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate and other polyester-based polymerization Polyolefin polymers such as polyolefins, polyethylene, polypropylene, etc. If the raw materials of these thermoplastic resins are derived from biomass, they will not affect the increase or decrease of carbon dioxide on the surface, and therefore the environmental load can be reduced, which is preferable.

[Slip agent] In the biaxially stretched polyamide film or base layer (layer A) of the present invention, it is preferable to contain organic lubricants such as fine particles or fatty acid amides as a lubricant in order to improve the sliding properties and facilitate handling. The biaxially stretched polyamide film of the present invention has good sliding properties and also has the effect of reducing bag breakage caused by friction.

As the above-mentioned fine particles, inorganic fine particles such as silica, kaolin, and zeolite, and polymer organic fine particles such as acrylic and polystyrene may be appropriately selected and used. In addition, in terms of transparency and sliding properties, it is preferable to use silica fine particles. The preferred average particle size of the aforementioned fine particles is 0.5 μm to 5.0 μm, more preferably 1.0 μm to 3.0 μm. If the average particle size is less than 0.5 μm, a large amount of addition is required in order to obtain good sliding properties. On the other hand, if it exceeds 5.0 μm, the surface roughness of the film becomes too large and the appearance tends to deteriorate.

In the case of using the aforementioned silica particles, the pore volume of silica is preferably in the range of 0.5 ml/g to 2.0 ml/g, more preferably 0.8 ml/g to 1.6 ml/g. If the pore volume is less than 0.5 ml/g, voids are likely to be generated and the transparency of the film is deteriorated. If the pore volume exceeds 2.0 ml/g, it tends to be difficult to form surface protrusions caused by fine particles.

The biaxially stretched polyamide film or base layer (layer A) in the present invention may contain fatty acid amide and/or fatty acid bisamide for the purpose of improving sliding properties. Examples of fatty acid amides and/or fatty acid bisamides include erucamide, stearic acid amide, ethylene bisstearate, ethylene bisbehenate, and ethylene bis Oleic acid amide and so on. The content of fatty acid amide and/or fatty acid bisamide in the biaxially stretched polyamide film of the present invention is preferably 0.01% by mass to 0.40% by mass, and more preferably 0.05% by mass to 0.30% by mass. If the content of fatty acid amide and/or fatty acid bisamide does not fall within the above-mentioned range, the sliding properties tend to deteriorate. On the other hand, if it exceeds the above range, the wettability tends to deteriorate.

In the biaxially stretched polyamide film or substrate layer (layer A) of the present invention, for the purpose of improving sliding properties, polyamide MXD6 resin, polyamide 12 resin, polyamide 66 resin, Polyamide resins such as polyamide 6-polyamide 12 copolymer resin and polyamide 6-polyamide 66 copolymer resin. Particularly preferred is polyamide MXD6 resin, and it is preferred to add 1% by mass to 10% by mass.

[Antioxidants] The biaxially stretched polyamide film or substrate layer (layer A) in the present invention may contain an antioxidant. As the antioxidant, a phenol-based antioxidant is preferred. The phenolic antioxidant is preferably a fully hindered phenolic compound or a partially hindered phenolic compound. Examples include: tetra-[methylene-3-(3',5'-di-tertiary butyl-4'-hydroxyphenyl) propionate] methane, β-(3,5-di-tertiary butyl) 4-hydroxyphenyl) stearyl propionate, 3,9-bis[1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylbenzene) Yl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane and the like. By containing the above-mentioned phenolic antioxidant, the film forming workability of the biaxially stretched polyamide film is improved. In particular, when a recycled film is used as a raw material, it is likely to cause thermal degradation of the resin, which results in poor film forming operations and a tendency to increase production costs. In this regard, by containing an antioxidant, the thermal degradation of the resin can be suppressed and the operability can be improved.

[Functional layer (B layer)] As an embodiment of the present invention, at least a single-area functional layer (layer B) is layered on the base layer (layer A), so that the surface characteristics can be improved. Layer B is a layer containing 70% by mass or more of polyamide 6 resin. By containing 70% by mass or more of polyamide 6 resin in the B layer, a biaxially stretched polyamide film with excellent mechanical strength such as impact strength or gas barrier properties against oxygen and the like can be obtained. As the polyamide 6 resin, the same resin as the polyamide 6 resin used in the aforementioned A layer can be used.

The layer B may contain various additives such as other thermoplastic resins, slip agents, heat stabilizers, antioxidants, antistatic agents or antifogging agents, ultraviolet absorbers, dyes, and pigments, according to the functions imparted to the surface of the layer B. When layer B is used on the outside of the packaging bag, it is not suitable to contain soft resins such as polyamide-based elastomers or polyolefin-based elastomers or materials that generate a large number of voids because of the need for friction and pinhole resistance.

The layer B may contain a thermoplastic resin in addition to the above-mentioned polyamide 6 within a range that does not impair the purpose of the present invention. Examples include: polyamide MXD6 resin, polyamide 11 resin, polyamide 12 resin, polyamide 66 resin, polyamide 6-polyamide 12 copolymer resin, polyamide 6-polyamide 66 copolymer Polyamide resins such as resins. If necessary, it can also contain thermoplastic resins other than polyamide series, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate and other polyester-based polymerization Polyolefin polymers such as polyolefins, polyethylene, polypropylene, etc.

In the layer B, in order to improve the sliding properties of the film, it is preferable to contain fine particles, an organic lubricant, or the like as a lubricant. By making the sliding property good, the operability of the film is improved, and the bag breakage caused by dragging is reduced.

As the aforementioned fine particles, inorganic fine particles such as silica, kaolin, and zeolite, and polymer organic fine particles such as acrylic and polystyrene are suitably selected and used. In addition, in terms of transparency and sliding properties, it is preferable to use silica fine particles.

The preferred average particle size of the aforementioned fine particles is 0.5 μm to 5.0 μm, more preferably 1.0 μm to 3.0 μm. If the average particle size is less than 0.5 μm, a large amount of addition is required in order to obtain good sliding properties. On the other hand, if it exceeds 5.0 μm, the surface roughness of the film becomes too large and the appearance tends to deteriorate.

In the case of using the aforementioned silica particles, the pore volume of silica is preferably in the range of 0.5 ml/g to 2.0 ml/g, more preferably 0.8 ml/g to 1.6 ml/g. If the pore volume is less than 0.5 ml/g, voids are easily generated and the transparency of the film deteriorates. If the pore volume exceeds 2.0ml/g, it tends to be difficult to form surface protrusions caused by fine particles.

As the aforementioned organic lubricant, it may contain fatty acid amide and/or fatty acid bisamide. Examples of fatty acid amides and/or fatty acid bisamides include erucamide, stearic acid amide, ethylene bisstearate, ethylene bisbehenate, and ethylene bis Oleic acid amide and so on. The content of the fatty acid amide and/or the fatty acid bisamide added to the layer B is preferably 0.01% by mass to 0.40% by mass, and more preferably 0.05% by mass to 0.30% by mass. If the content of fatty acid amide and/or fatty acid bisamide does not fall within the above-mentioned range, the sliding properties tend to deteriorate. On the other hand, if it exceeds the above range, the wettability tends to deteriorate.

In layer B, for the purpose of improving the sliding properties of the film, polyamide resins other than polyamide 6 can be added, such as polyamide MXD6 resin, polyamide 11, polyamide 12 resin, and polyamide 66 Resin, polyamide 6-polyamide 12 copolymer resin, polyamide 6-polyamide 66 copolymer resin, etc. Particularly preferred is polyamide MXD6 resin, and it is preferred to add 1% by mass to 10% by mass. If it is less than 1% by mass, the sliding property improvement effect of the film is small. When it is more than 10% by mass, the sliding property improvement effect of the film is saturated. Polyamide MXD6 resin is produced by polycondensation of meta-xylylenediamine and adipic acid. The relative viscosity of polyamide MXD6 is preferably 1.8 to 4.5, more preferably 2.0 to 3.2. When the relative viscosity is less than 1.8 or greater than 4.5, it is sometimes difficult to use an extruder to knead the polyamide resin.

When adding fine particles, organic lubricants, or polyamide resins such as polyamide MXD6 resin to the B layer for the purpose of improving the sliding properties of the film, if these components are reduced in the base layer (layer A The addition amount in) is preferable because a film having excellent transparency and sliding properties can be obtained.

In addition, in the layer B, for the purpose of improving adhesiveness, polyamide resins other than polyamide 6 may be added. In this case, copolymerized polyamide resins such as polyamide 6-polyamide 12 copolymer resin and polyamide 6-polyamide 66 copolymer resin are preferred.

The layer B of the biaxially stretched polyamide film in the present invention may contain an antioxidant in the same manner as the layer A described above.

As a method of adding auxiliary materials or additives such as slip agents or antioxidants to the biaxially stretched polyamide film or base layer (layer A) and functional layer (layer B) of the present invention, it can be used during resin polymerization or It is added during the melt extrusion of the extruder. It is also possible to make a high-concentration masterbatch and add the masterbatch to the polyamide resin during film production. It can be carried out by such a well-known method.

[Thickness composition of biaxially stretched polyamide film] The thickness of the biaxially stretched polyamide film in the present invention is not particularly limited. When used as a packaging material, it is usually below 100μm. Generally, a film with a thickness of 5μm to 50μm is used, especially a film with a thickness of 8μm to 30μm is used. .

In the thickness structure of each layer of the biaxially stretched polyamide film in the present invention, when the thickness of the B layer accounts for most of the total film thickness, the bending pinhole resistance is reduced. Therefore, in the present invention, it is preferable to set the thickness of the A layer to 50% to 93%, especially 70% to 93%, of the total thickness of the A layer and the B layer.

[Adhesive modified layer] The easily adhesive polyamide film of the present invention has an adhesive modified layer on at least one side, and the above-mentioned adhesive modified layer has a coating amount of 0.01 g/m ² to 3 g/m in terms of solid content. ^{2. It} is composed of any one of polyester resin, polyurethane resin, and/or polyacrylic resin. The aforementioned subsequent reforming layer is preferably provided by applying a coating liquid and drying before winding the film into a milling roll in the film manufacturing step. The coating liquid can be applied to unstretched films, uniaxially stretched films, and/or biaxially stretched films. In the case of producing a film by the stepwise biaxial stretching method, a coating liquid is usually applied to the uniaxially stretched film and dried. In the case of manufacturing a film by simultaneous biaxial stretching, a coating liquid is usually applied to the unaxially stretched film and dried.

To set the coating liquid for the subsequent modified layer in the present invention, the coating liquid is applied and dried before the film is wound into a milling roll in the film manufacturing step to set the coating film, so in order to ensure For safety and hygiene, it is preferable to use an aqueous resin dispersion.

[The polyester resin used in the modified layer] When a polyester resin is provided as the adhesive reforming layer in the present invention, a copolyester resin can be selected as the polyester resin. Copolyester resin refers to a polycondensate of a dicarboxylic acid component, a diol component, and other ester forming components. As the dicarboxylic acid component contained as a constituent in the copolyester resin, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenylene dicarboxylic acid Aromatic dicarboxylic acids such as carboxylic acid, isophthalic acid-5-sodium sulfonate, aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid Acids, alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and tetrahydrophthalic acid.

In addition to the above-mentioned dicarboxylic acid components, in order to impart water dispersibility, 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2,6 can be used. -Salts of dicarboxylic acid and 5(4-sulfophenoxy)isophthalic acid. Among them, it is preferable to use 5-sodium isophthalate sulfonate in the range of 1 mol% to 10 mol%.

Examples of the glycol component contained in the copolyester resin include: ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, and neopentyl glycol , Aliphatic diols such as 1,6-hexanediol and polyethylene glycol, alicyclic diols such as 1,4-cyclohexanedimethanol, 4,4'-bis(hydroxyethyl)bisphenol A, etc. Aromatic diols, bis(polyoxyethylene glycol) bisphenol ether, and the like. The polyester resin is preferably used as a coating liquid of an aqueous dispersion.

When a polyester resin is provided as the adhesive reforming layer in the present invention, the polyester resin is particularly preferred because the acrylic graft copolymer polyester described later can improve the water-resistant laminate strength.

[The polyurethane resin used for the next modified layer] When a polyurethane resin is provided as the subsequent reforming layer in the present invention, examples of the polyurethane resin include polyols having two or more active hydrogens and organic polyisocyanates. The polyurethane resin obtained by the reaction. As the polyols, for example, saturated polyester polyols; polyether polyols (for example, polyethylene glycol, polytetramethylene glycol, etc.); amino alcohols (for example, ethanolamine, diethanolamine, triethanolamine, etc.); Ethanolamine, etc.); Unsaturated polyester polyols (for example, polycondensation of a single unsaturated polycarboxylic acid or a mixture of unsaturated polycarboxylic acid and saturated polycarboxylic acid, and a mixture of saturated polyols and unsaturated polyols) Obtained unsaturated polyester polyols), polybutadiene polyols (such as 1,2-polybutadiene polyol, 1,4-polybutadiene polyol, etc.), acrylic polyols (using Various acrylic monomers and acrylic monomers having hydroxyl groups are copolymerized to obtain polyols having unsaturated double bonds, such as acrylic polyols having hydroxyl groups in the side chain. Examples of organic polyisocyanates include aromatic polyisocyanates (for example, diphenylmethane diisocyanate, toluene diisocyanate, etc.), aliphatic polyisocyanates (for example, hexamethylene diisocyanate, etc.), and alicyclic polyisocyanates. (For example, isophorone diisocyanate, etc.), aromatic/aliphatic polyisocyanates (for example, xylylene diisocyanate), and polyisocyanates obtained by pre-reacting these isocyanates with low molecular weight polyols.

The polyurethane resin can be produced by a known method. At the time of production, two or more unreacted isocyanate groups must be present in the resulting prepolymer. The isocyanate group is preferably blocked, especially when preparing an aqueous coating liquid. This blocking is well known as the blocking of isocyanate, and free isocyanate groups can be regenerated by heating. Examples of the blocking agent include bisulfites, alcohols, oximes, active methylene compounds, imidazoles, endoamides, imine compounds, amide compounds, and imine compounds.

The reaction between these end-capping agents and the isocyanate groups in the polyurethane prepolymer can be carried out at a temperature from room temperature to 100°C, and a urethane catalyst can be used as needed. Here, in order to impart stable water dispersibility and water solubility to the polyurethane prepolymer, a hydrophilic group may be introduced into the molecule. Examples of the hydrophilic group include -SO ₃ M (here, M is an alkali metal or alkaline earth metal), -OH, -COOR (here, R is a residue of ammonia or tertiary amine), and the like. Among these, carboxyl groups neutralized with ammonia or tertiary amines are particularly preferred. In order to introduce the carboxyl group neutralized by ammonia or tertiary amine into the polyurethane prepolymer, for example, there is the following method: use a carboxyl-containing polyhydroxy compound as the synthesis of the polyurethane prepolymer One of the raw materials for the reaction: reacting the isocyanate groups of the polyurethane prepolymer with unreacted isocyanate groups with the hydroxyl-containing carboxylic acid or the amine-containing carboxylic acid, and then the reaction product is stirred at high speed Adding to ammonia or tertiary amine aqueous solution for neutralization, etc. The polyurethane resin is preferably used as an aqueous dispersion coating liquid.

[The polyacrylic resin used in the modified layer] When a polyacrylic resin is provided as the adhesive reforming layer in the present invention, the polyacrylic resin may be acrylic acid polymerized by polymerizing acrylic acid or methacrylic acid, or a salt or ester of acrylic acid or methacrylic acid. Things. Examples of acrylate-based and methacrylate-based monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, and methyl acrylate. Methyl acrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, etc. Examples of salts of acrylic acid and methacrylic acid include sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, ammonium acrylate, and ammonium methacrylate. In addition to these essential components, acrylamide, methacrylamide, aminoethyl methacrylate, aminomethyl methacrylate, N-methylol acrylamide, N-methoxymethyl can also be added. Acrylic monomers such as acrylamide. In the polyacrylic resin, monomers such as vinyl chloride, vinyl acetate, styrene, vinyl ether, butadiene, isoprene, and sodium vinyl sulfonate can also be used as copolymerization components. In addition, in order to improve the functionality of the coating film, the acrylic polymer preferably contains an acrylate component, a methacrylate component, an acrylic acid component, an acrylamide component, a 2-hydroxyethyl acrylate component, and N-methylol Hydrophilic components such as acrylamide components are used as copolymerization components. In addition, it may be a copolymer having a functional group in the side chain of the molecule. In addition, the acrylic polymer can also be obtained by using a hard component such as methyl methacrylate or ethyl methacrylate as a main component and copolymerizing a soft component such as acrylate as a copolymer component. The polyacrylic resin is preferably used as an aqueous dispersion coating liquid.

[Following the acrylic graft copolymer polyester resin used in the modified layer] When a polyester resin is provided as the adhesive reforming layer in the present invention, it is particularly preferable to graft-polymerize a polyacrylic resin to a polyester resin to form a copolyester, and therefore it will be described in detail below. As the coating solution for forming the subsequent modified layer, an aqueous dispersion of a copolyester obtained by graft-polymerizing a polyacrylic resin to a polyester resin is particularly preferred. The average particle diameter of the acrylic graft copolymerized polyester particles in the aqueous dispersion of acrylic acid graft copolymerized polyester is determined by laser light scattering method to be 500 nm or less, preferably 10 nm to 500 nm, and more preferably 10 nm to 300 nm. If the average particle diameter exceeds 500 nm, the strength of the coating film after application may decrease.

The content of acrylic graft copolymerized polyester particles in the aqueous dispersion of acrylic graft copolymerized polyester is usually 1% by mass to 50% by mass, preferably 3% by mass to 30% by mass. The particles in the aqueous dispersion of acrylic graft copolymerized polyester that can be used in the present invention exhibit a core-shell structure with a polyester main chain as the core in an aqueous dispersion medium.

The adhesion between the coating film and the polyamide film obtained from the above acrylic graft copolymer polyester aqueous dispersion is very excellent. Furthermore, since it has excellent blocking resistance, it can be used without any problems in film substrates with relatively low glass transition points. In addition, when it is made into a laminate, the adhesiveness with respect to the adhesive used when printing ink or sealant layer is laminated is also very good. The durability of the obtained laminated film (also called laminated film) in retort treatment or boiling water treatment is significantly improved.

[Polyester main chain of acrylic graft copolymer polyester] The polyester that can be used as the main chain of the grafted polyester in the present invention is preferably a saturated or unsaturated polyester synthesized from at least a dicarboxylic acid component and a diol component, and the obtained polyester may be one polymer Or a mixture of two or more polymers. In addition, it is preferably a polyester that does not disperse or dissolve in water by itself. The weight average molecular weight of the polyester that can be used in the present invention is 5,000 to 100,000, preferably 5,000 to 50,000. If the weight average molecular weight is less than 5,000, the physical properties of the coating film, such as the post-processability of the dried coating film, decrease. Furthermore, if the weight average molecular weight is less than 5000, the polyester itself which becomes the main chain is easily water-soluble, so the formed grafted polyester cannot form a core-shell structure described later. If the weight average molecular weight of the polyester exceeds 100,000, it is difficult to disperse in water. From the viewpoint of water dispersion, it is preferably 100,000 or less. The glass transition point is 30°C or less, preferably 10°C or less.

The dicarboxylic acid component preferably contains at least one aromatic dicarboxylic acid, at least one aliphatic and/or alicyclic dicarboxylic acid, and at least one free radical polymerizable unsaturated double bond. A mixture of carboxylic acids and dicarboxylic acids. The aromatic dicarboxylic acid contained in the dicarboxylic acid mixture is 30 mol% to 99.5 mol%, preferably 40 mol% to 99.5 mol%, and the aliphatic and/or alicyclic dicarboxylic acid is 0 mol% to 70 mol%, preferably 0 mol% to 60 mol%, dicarboxylic acid with radically polymerizable unsaturated double bond is 0.5 mol% to 10 mol%, preferably 2 mol% to 7 mol%, more preferably 3 mol% to 6 mol%. When the content of dicarboxylic acid containing radical polymerizable unsaturated double bonds is less than 0.5 mol%, it is difficult to effectively graft the radical polymerizable monomer to the polyester, and it is dispersed in an aqueous medium. The particle size tends to become larger and the dispersion stability tends to decrease.

As the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, and the like can be used. Furthermore, 5-sodium isophthalic acid 5-sulfonate can also be used as needed. As the aliphatic dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, anhydrides of these, and the like can be used. As the alicyclic dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, anhydrides of these, and the like can be used.

As dicarboxylic acids containing radically polymerizable unsaturated double bonds, fumaric acid, maleic acid, maleic anhydride, itaconic acid, α,β-unsaturated dicarboxylic acids, Citraconic acid; 2,5-norbornene dicarboxylic acid anhydride, tetrahydrophthalic anhydride, etc. as alicyclic dicarboxylic acids containing unsaturated double bonds. Among these, preferred are fumaric acid, maleic acid and 2,5-norbornene dicarboxylic acid (endo-bicyclo-(2,2,1)-5-heptene-2,3 -Dicarboxylic acid).

The diol component is composed of at least one of aliphatic diols having 2 to 10 carbon atoms, alicyclic diols having 6 to 12 carbon atoms, and ether bond-containing diols. As aliphatic diols with 2 to 10 carbon atoms, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol can be used , 1,6-hexanediol, etc. As the alicyclic diol having 6 to 12 carbon atoms, 1,4-cyclohexanedimethanol and the like can be used. As the ether bond-containing glycol, two phenolic hydroxyl groups of diethylene glycol, triethylene glycol, dipropylene glycol, and bisphenols can be added with 1 mol to several mol of ethylene oxide or Diols obtained from propylene oxide, for example, 2,2-bis(4-hydroxyethoxyphenyl)propane and the like. Polyethylene glycol, polypropylene glycol, or polytetramethylene glycol can also be used as needed.

In addition to the above-mentioned dicarboxylic acid component and diol component, polycarboxylic acid and/or polyol having trifunctionality or higher may be copolymerized. As a polycarboxylic acid with more than three functions, trimellitic acid (anhydride), pyromellitic acid (anhydride), benzophenone tetracarboxylic acid (anhydride), trimellitic acid, ethylene glycol bis(anhydride) can be used Trimellitic acid ester), triglyceride (dehydrated trimellitic acid ester) and so on. As a polyhydric alcohol with more than trifunctionality, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, etc. can be used. The polycarboxylic acid and/or polyol with more than trifunctionality may be 0 mol% to 5 mol% relative to all polycarboxylic acid components containing the above-mentioned dicarboxylic acid components or all polyol components containing the above-mentioned diol components , It is preferably used in the range of 0 mol% to 3 mol%.

[Grafted part of acrylic graft copolyester] The grafted part of the acrylic graft copolyester that can be used in the present invention is derived from an acrylic polymer of a monomer mixture containing at least one radical polymerizable monomer, and the aforementioned radical polymerizable monomer has a hydrophilic group, Or have a group that can be changed to a hydrophilic group later.

The weight average molecular weight of the polymer constituting the graft portion is 500 to 50,000, preferably 4,000 to 50,000. When the weight average molecular weight is less than 500, the grafting rate is reduced, and therefore the polyester cannot be sufficiently hydrophilic, and it is generally difficult to control the weight average molecular weight of the grafted portion to less than 500. The grafted part forms a hydrated layer of dispersed particles. In order for the particles to have a sufficiently thick hydrated layer to obtain a stable dispersion, the weight average molecule derived from the grafted portion of the radically polymerizable monomer is preferably 500 or more. In terms of polymerizability in solution polymerization, the upper limit of the weight average molecular weight of the grafted portion of the radically polymerizable monomer is preferably 50,000 as described above. The molecular weight can be controlled within this range by appropriately selecting the polymerization starting dose, monomer dropping time, polymerization time, reaction solvent, and monomer composition, and appropriately combining a chain transfer agent or polymerization inhibitor as necessary. The glass transition point is 30°C or less, preferably 10°C or less.

As the hydrophilic group possessed by the radically polymerizable monomer, a carboxyl group, a hydroxyl group, a sulfonic acid group, an amido group, a quaternary ammonium salt, a phosphoric acid group, etc. can be used. As the group that can be changed to a hydrophilic group, an acid anhydride, glycidyl group, chlorine, etc. can be used. The dispersibility of the grafted polyester in water can be controlled by the hydrophilic group introduced into the polyester by grafting. Among the above-mentioned hydrophilic groups, since an acid value known in the technical field can be used to accurately determine the amount of introduction into the grafted polyester, it is preferable to control the dispersibility of the grafted polyester in water. It is a carboxyl group.

As carboxyl group-containing radical polymerizable monomers, there are acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, etc., and can be easily used in contact with water/amine Produce carboxylic acid maleic anhydride, itaconic anhydride, methacrylic anhydride, etc. Preferred carboxyl group-containing radical polymerizable monomers are acrylic anhydride, methacrylic anhydride and maleic anhydride.

In addition to the above-mentioned hydrophilic group-containing radical polymerizable monomer, it is preferable to copolymerize at least one kind of radical polymerizable monomer that does not contain a hydrophilic group. In the case of monomers containing only hydrophilic groups, the main link of the polyester cannot be branched smoothly, and it is difficult to obtain a good aqueous dispersion of the copolyester. Highly efficient grafting can be achieved by copolymerizing at least one radically polymerizable monomer that does not contain a hydrophilic group.

As the radically polymerizable monomer not containing a hydrophilic group, one type or a combination of one or more types of monomers having an ethylenically unsaturated bond and not containing a hydrophilic group as described above can be used. Examples of such monomers include acrylates such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and hydroxypropyl acrylate; Methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, lauryl methacrylate, 2-methacrylate Methacrylates such as hydroxyethyl and hydroxypropyl methacrylate; acrylic acid or methacrylic acid derivatives such as acrylamide, N-methylol acrylamide, diacetone acrylamide, etc.; acrylonitrile, methacrylonitrile Nitriles such as vinyl acetate, vinyl propionate, vinyl benzoate and other vinyl esters; vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and other vinyl ethers; vinyl methyl ketone, vinyl hexyl Vinyl ketones such as ketones and methyl isopropenyl ketones; N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinyl chloride , Vinylidene chloride, vinyl bromide, vinyl fluoride and other halogenated vinyl compounds; styrene, α-methylstyrene, tertiary butyl styrene, vinyl toluene, vinyl naphthalene and other aromatic vinyl compounds. These monomers can be used individually or in combination of 2 or more types.

The use ratio of the hydrophilic group-containing monomer to the hydrophilic group-free monomer is determined by considering the amount of hydrophilic group introduced into the grafted polyester species, usually the mass ratio (hydrophilic group-containing monomer: The monomer without a hydrophilic group is 95:5 to 5:95, preferably 90:10 to 10:90, and more preferably 80:20 to 40:60.

When a carboxyl group-containing monomer is used as a hydrophilic group-containing monomer, the total acid value of the grafted polyester is 600eq./10 ⁶ g to 4000eq./10 ⁶ g, preferably 700eq./10 ⁶ g to 3000eq./10 ⁶ g, preferably 800eq./10 ⁶ g to 2500eq./10 ⁶ g. When the acid value is ^{less than 600eq./10 6} g, it is not easy to obtain an aqueous dispersion of the copolyester with a small particle size when the grafted polyester is dispersed in water, and the dispersion stability of the aqueous dispersion of the copolyester decreases . When the acid value is 4000 eq./10 ⁶ g or more, the water resistance of the subsequent modified layer formed from the aqueous dispersion of the copolyester becomes low.

The mass ratio of the polyester main chain to the grafted part (polyester: radical polymerizable monomer) in the acrylic graft copolymerized polyester is 40:60 to 95:5, preferably 55:45 to 93:7, More preferably, it is in the range of 60:40 to 90:10.

When the mass ratio of the polyester main chain is 40% by mass or less, the excellent performance of the parent polyester that has been explained, that is, high processability, excellent water resistance, and various substrates cannot be fully utilized. On the contrary, it will add the undesirable properties of acrylic resin, that is, low processability, gloss, water resistance, etc. When the mass ratio of the polyester is 95% by mass or more, the amount of hydrophilic groups in the grafted portion that imparts hydrophilicity to the grafted polyester is insufficient, and a good aqueous dispersion cannot be obtained.

[Solvent for grafting reaction of acrylic graft copolymer polyester] The solvent for the grafting reaction is preferably composed of an aqueous organic solvent with a boiling point of 50°C to 250°C. Here, the term "aqueous organic solvent" refers to an organic solvent whose solubility in water at 20°C is at least 10 g/L or more, preferably 20 g/L or more. Aqueous organic solvents with a boiling point exceeding 250°C have a slow evaporation rate, and therefore cannot be sufficiently removed by high-temperature firing of the coating film after the coating film is formed, so it is not suitable. In addition, for an aqueous organic solvent with a boiling point of 50°C or less, when carrying out the grafting reaction using the aqueous organic solvent as the solvent, it is necessary to use an initiator that decomposes into free radicals at a temperature of 50°C or less. The risk of the above increases, so it is unsatisfactory.

As an aqueous organic solvent that dissolves polyester well and relatively well dissolves polymerizable monomers containing hydrophilic groups, especially polymerizable monomers containing carboxyl groups, and polymers of the polymerizable monomers (group 1 ), including: esters, such as ethyl acetate; ketones, such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; cyclic ethers, such as tetrahydrofuran, dioxane, and 1, 3-Dioxolane; glycol ethers, such as ethylene glycol dimethyl ether, propylene glycol methyl ether, propylene glycol propyl ether, ethylene glycol ethyl ether, and ethylene glycol butyl ether; carbitols, such as methyl Carbitol, ethyl carbitol, and butyl carbitol; lower esters of glycols or glycol ethers, such as ethylene glycol diacetate and ethylene glycol ethyl ether acetate; ketone alcohols, For example, diacetone alcohol; N-substituted amides, such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

In contrast, it is an aqueous organic solvent that hardly dissolves polyester, but dissolves polymerizable monomers containing hydrophilic groups, especially polymerizable monomers containing carboxyl groups, and polymers of the polymerizable monomers relatively well. (The second group) includes water, lower alcohols, lower glycols, lower carboxylic acids, lower amines, and the like. Preferred are alcohols and diols having 1 to 4 carbon atoms.

In the case of carrying out the grafting reaction in a single solvent, one of the first group of aqueous organic solvents can be used. In the case of carrying out in a mixed solvent, multiple types of the first group of aqueous organic solvents, or at least one type of the first group of aqueous organic solvents, and at least one type of the second group of aqueous organic solvents can be used.

The grafting reaction can be carried out in either a single solvent from the first group of aqueous organic solvents and a mixed solvent composed of each of the first group and the second group of aqueous organic solvents. . However, in terms of the behavior of the grafting reaction, the appearance and properties of the grafted reaction product and the aqueous dispersion derived from the grafted reaction product, it is preferable to use the first group and the second group A mixed solvent composed of each of the water-based organic solvents. The reason is that in the grafting reaction of polyester, it is easy to cause gelation of the system due to the crosslinking between polyester molecules, but the use of a mixed solvent as follows can prevent gelation.

By measuring the viscosity of the polyester in these solutions, it is confirmed that in the solvent of the first group, the polyester molecular chain is in a state of elongating to a larger chain extension. On the other hand, the first group/second group In the mixed solvent, the polyester molecular chain is in a state of being entangled into a small unfolded ball. In the state where the polyester molecular chain is extended, all the reaction points in the polyester main chain can contribute to the grafting reaction, so the grafting rate of polyester becomes higher, but at the same time the incidence of intermolecular crosslinking also changes. high. On the other hand, when the polyester molecular chain becomes a linear ball, the reaction points inside the linear ball cannot contribute to the grafting reaction, and the incidence of cross-linking between molecules is also reduced. Therefore, by selecting the type of solvent, the state of the polyester molecule can be adjusted, whereby the grafting rate and the intermolecular crosslinking based on the grafting reaction can be adjusted.

In a mixed solvent system, it can achieve both high grafting rate and gelation inhibition. The optimal mixing ratio of the mixed solvent of the first group/second group can be changed according to the solubility of the polyester used, etc. Generally, the mass ratio of the mixed solvent of the first group/second group is 95:5 to 10 : 90, preferably 90:10 to 20:80, more preferably 85:15 to 30:70.

[Free radical polymerization initiator and chain transfer agent for acrylic graft copolymer polyester] As the radical polymerization initiator that can be used, organic peroxides or organic azo compounds known to those skilled in the art to which the present invention pertains can be used. Examples of organic peroxides include benzyl peroxide and t-butyl peroxypivalate. Examples of organic azo compounds include 2,2'-azobisisobutyronitrile, 2,2' -Azobis(2,4-dimethylvaleronitrile) and the like. The amount of the radical polymerization initiator used for the grafting reaction is at least 0.2% by mass or more, preferably 0.5% by mass or more, relative to the radical polymerizable monomer. In addition to the polymerization initiator, a chain transfer agent for adjusting the chain length of the grafted part may be used as needed, such as octyl mercaptan, mercaptoethanol, 3-tert-butyl-4-hydroxyanisole, and the like. In this case, it is more desirable to add in the range of 0% by mass to 5% by mass relative to the radical polymerizable monomer.

[Grafting Reaction of Acrylic Graft Copolyester] The grafted portion is formed by the following method, that is, the radical polymerizable unsaturated double bond in the polyester is polymerized with the radical polymerizable monomer and/or the radical polymerizable unsaturated double bond is polymerized with the aforementioned radical polymerizable monomer. The free-radical polymerizable monomer reacts with the living end of the polymer. The reaction product after the completion of the grafting reaction contains, in addition to the target grafted polyester, a polymer that does not have a grafted part and a radically polymerizable monomer that is not grafted to the polyester. In the case where the production ratio of grafted polyester in the reaction product is low, and the ratio of polyester without grafting part to polymer with ungrafted radical polymerizable monomer is high, it is impossible to obtain good stability Dispersions.

Generally, the grafting reaction can be carried out by adding the above-mentioned radical polymerizable monomer and a radical initiator to the solution containing the above-mentioned polyester under heating, or it can be carried out by dripping for a certain period of time respectively, and then The reaction proceeds by continuing to heat under stirring for a certain period of time. Alternatively, if necessary, a part of the radical polymerizable monomer can be added first, and then the remaining radical polymerizable monomer and the polymerization initiator are added dropwise for a certain period of time, and then the heating is continued under stirring for a certain period of time. Grafting reaction.

The mass ratio of the polyester to the solvent is based on the reactivity of the polyester and the radical polymerizable monomer and the solvent solubility of the polyester to select the mass ratio for uniformly reacting in the polymerization step. It is usually 70:30 to 10:90, preferably in the range of 50:50 to 15:85.

[Water Dispersion of Acrylic Graft Copolyester] The grafted polyester that can be used in the present invention can be water-dispersed by adding it to an aqueous medium in a solid state, or dissolving it in a hydrophilic solvent, and then adding it to an aqueous medium. In particular, when a monomer having an acidic group such as a sulfonic acid group and a carboxyl group is used as a radical polymerizable monomer having a hydrophilic group, by neutralizing the grafted polyester with a basic compound, The grafted polyester is easily dispersed in water in the form of fine particles with an average particle diameter of 500 nm or less to prepare an aqueous dispersion of the copolyester.

The basic compound is preferably a compound that volatilizes when the coating film is formed, or when the curing agent described below is blended, it is preferably a compound that volatilizes during firing and curing. As such a basic compound, ammonia, organic amines, etc. are preferable. Examples of organic amines include: triethylamine, N,N-diethylethanolamine, N,N-dimethylethanolamine, aminoethanolamine, N-methyl-N,N-diethanolamine, isopropyl Amine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, etc. The amount of the basic compound used is preferably an amount that at least partially neutralizes or completely neutralizes the carboxyl group contained in the grafted portion so that the pH of the aqueous dispersion becomes in the range of 5.0 to 9.0.

As a method of preparing an aqueous dispersion of a copolyester neutralized with a basic compound, the aqueous dispersion can be prepared by the following method: After the grafting reaction is completed, the solvent is freed from the solvent by an extruder under reduced pressure. The reaction liquid is removed to become a melt or solid (particles, powder, etc.), and then the resulting melt or solid (particles, powder, etc.) is poured into an aqueous alkaline compound and stirred under heating, or at the end At the time of the grafting reaction, the alkaline compound aqueous solution was immediately put into the reaction solution, and heating and stirring were continued (one pot method). In terms of convenience, the single-slot method is preferred. In this case, if the boiling point of the solvent used in the grafting reaction is 100°C or less, a part or all of it can be easily removed by distillation.

[Crosslinking agent added in coating solution] In the above-mentioned polyester resin, polyurethane resin, and/or polyacrylic resin coating solution, a crosslinking agent (curing resin) is further mixed and cured, thereby enabling the modification of the adhesive The quality layer imparts a high degree of water resistance. As the crosslinking agent, phenol-formaldehyde resins that are condensation products of alkylated phenols, cresols, etc. and formaldehyde; adducts of urea, melamine, benzoguanamine, etc., and formaldehyde can be used. Amino resins such as alkyl ether compounds composed of alcohols with 1 to 6 atoms; multifunctional epoxy compounds; multifunctional isocyanate compounds; blocked isocyanate compounds; multifunctional aziridine compounds; oxazoline compounds Wait. These crosslinking agents can be used individually or in mixture of 2 or more types, respectively. The blending amount of the crosslinking agent is preferably 5 to 40% by mass relative to the grafted polyester.

As a method of formulating the crosslinking agent, when (1) the crosslinking agent is water-soluble, a method of directly dissolving or dispersing in an aqueous dispersion can be used, or when (2) the crosslinking agent is oil-soluble , Can be used for the method of adding a crosslinking agent before or after the water dispersion after the grafting reaction is completed, and making the crosslinking agent coexist with the polyester in the core part. These methods can be appropriately selected according to the kind and properties of the crosslinking agent. Furthermore, a curing agent or accelerator may be used in combination with the crosslinking agent.

The adhesive modified layer used in the present invention may contain additives such as antistatic agents, inorganic slip agents, and organic slip agents in order to impart antistatic properties and sliding properties to the extent that the effects of the present invention are not impaired. When an antistatic agent, an inorganic slip agent, an organic slip agent, etc. are applied to the surface of the film, in order to prevent the detachment of these additives, it is preferably contained in the subsequent reforming layer.

[Manufacturing method of easy-adhesive polyamide film] The easy-adhesive polyamide film of the present invention is produced by forming an adhesive modified layer on the biaxially stretched polyamide film of the present invention by the method described later. The biaxially stretched polyamide film in the present invention can be produced by a known production method. For example, the stepwise biaxial stretching method and the synchronous biaxial stretching method can be cited. The gradual biaxial stretching method can increase the film forming speed, and is therefore advantageous in terms of manufacturing cost, and is therefore preferred. The manufacturing method of the biaxially stretched polyamide film in the present invention will be further described. First, the raw material resin is melt-extruded using an extruder, extruded from a T-die into a film, and cast on a cooling roll for cooling to obtain an unstretched film. The melting temperature of the resin is preferably 200°C to 300°C. If the temperature is less than 200°C, unmelted materials may be generated, which may cause defects such as defects in appearance. If it exceeds 300°C, resin degradation may be observed, resulting in a decrease in molecular weight and appearance.

The temperature of the cooling roll is preferably -30°C to 80°C, and more preferably 0°C to 50°C. In order to cast the film-like melt extruded from the T-die on a rotating cooling drum for cooling to obtain an unstretched film, for example, a method using an air knife or an electrostatic adhesion method using electrostatic charge can be preferably applied. In particular, the latter can be preferably used.

In addition, it is preferable that the cast unstretched film is also cooled on the opposite side of the cooling roll. For example, it is preferable to use the following methods together: a method of contacting the cooling liquid in the tank on the opposite side of the unstretched film cooling roll, a method of applying a liquid evaporated by a spray nozzle, and a method of cooling by blowing a high-speed fluid Wait. The unstretched film thus obtained is stretched in a biaxial direction to obtain a biaxially stretched polyamide film.

As the stretching method in the MD direction, multi-stage stretching such as one-stage stretching or two-stage stretching can be used. As will be described later, in terms of physical properties and the uniformity (isotropy) of physical properties in the MD and TD directions, multi-stage MD extensions such as two-stage extensions are preferred, rather than one-stage extensions . The extension in the MD direction in the stepwise biaxial extension method is preferably roll extension.

The lower limit of the stretching temperature in the MD direction is preferably 50°C, more preferably 55°C, and still more preferably 60°C. If it does not reach 50°C, the resin may not be softened and may be difficult to stretch. The upper limit of the stretching temperature in the MD direction is preferably 120°C, more preferably 115°C, and still more preferably 110°C. If it exceeds 120°C, the resin may become too soft and cannot be stretched stably.

The lower limit of the stretching magnification in the MD direction (in the case of stretching in multiple stages, the total stretching magnification obtained by multiplying the magnifications of each stage) is preferably 2.2 times, more preferably 2.5 times, and even more preferably 2.8 times. If it is less than 2.2 times, the thickness accuracy in the MD direction may decrease, and the crystallinity may become too low, and the impact strength may decrease. The upper limit of the stretching ratio in the MD direction is preferably 5.0 times, more preferably 4.5 times, and most preferably 4.0 times. If it exceeds 5.0 times, the subsequent extension may become difficult.

In addition, in the case of stretching in the MD direction in multiple stages, the stretching in each stage can be used to perform the stretching as described above, but regarding the magnification, the stretching must be adjusted so that the product of the stretching magnification in all MD directions becomes 5.0 or less Magnification. For example, in the case of two-stage extension, it is preferable to set the extension in the first stage to 1.5 times to 2.1 times, and to set the extension in the second stage to 1.5 times to 1.8 times.

The film stretched in the MD direction is stretched in the TD direction using a tenter, and undergoes heat-fixing and relaxation treatments (also called relaxation treatments). The lower limit of the stretching temperature in the TD direction is preferably 50°C, more preferably 55°C, and still more preferably 60°C. If it is less than 50°C, the resin may not be softened and stretching may become difficult. The upper limit of the stretching temperature in the TD direction is preferably 190°C, more preferably 185°C, and still more preferably 180°C. If it exceeds 190°C, crystallization may occur and stretching may become difficult.

The lower limit of the stretching magnification in the TD direction (in the case of stretching in multiple stages, the total stretching magnification obtained by multiplying the magnifications of each stage) is preferably 2.8, more preferably 3.2 times, and more preferably 3.5 times, especially The best is 3.8 times. If it is less than 2.8, the thickness accuracy in the TD direction may decrease, and the crystallinity may become too low and the impact strength may decrease. The upper limit of the stretching ratio in the TD direction is preferably 5.5 times, more preferably 5.0 times, still more preferably 4.7, particularly preferably 4.5, and most preferably 4.3 times. If it exceeds 5.5 times, productivity may decrease significantly.

The selection of the heat-fixing temperature is an important element in the present invention. As the heat-fixing temperature is increased, the crystallization and alignment of the film will be relaxed, which can increase the impact strength and reduce the heat shrinkage rate. On the other hand, when the heat setting temperature is low, crystallization and alignment relaxation are insufficient, and the heat shrinkage rate cannot be sufficiently reduced. In addition, if the heat-fixing temperature becomes too high, deterioration of the resin will occur, and the toughness of the film such as impact strength will be quickly lost.

The lower limit of the heat fixing temperature is preferably 180°C, more preferably 200°C. If the heat-fixing temperature is low, the heat shrinkage rate becomes too large, the appearance after lamination decreases, and the lamination strength tends to decrease. The upper limit of the heat fixing temperature is preferably 230°C, more preferably 220°C. If the heat fixing temperature is too high, the impact strength tends to decrease.

The time of heat fixation is preferably 0.5 second to 20 seconds. Furthermore, it is 1 second to 15 seconds. The heat-fixing time can be set to an appropriate time by matching with the heat-fixing temperature or the wind speed in the heat-fixing area. If the heat fixing conditions are too weak, crystallization and alignment relaxation become insufficient, causing the above-mentioned problems. If the heat fixing conditions are too strong, the film strength and toughness will decrease.

The relaxation treatment after the heat fixation treatment is an effective way to control the heat shrinkage rate. The temperature for performing the relaxation treatment can be selected in the range of the heat-fixing treatment temperature to the glass transition temperature (Tg) of the resin, but it is preferably from the heat-fixing treatment temperature -10°C to Tg+10°C. If the relaxation temperature is too high, the shrinkage speed will be too fast to cause strain, etc., so it is not good. Conversely, if the relaxation temperature is too low, the relaxation treatment cannot be performed, and only sagging occurs, but the thermal shrinkage rate does not decrease, and the dimensional stability deteriorates.

The lower limit of the relaxation rate in the relaxation treatment is preferably 0.5%, more preferably 1%. If it is less than 0.5%, the thermal shrinkage rate may not be sufficiently reduced in some cases. The upper limit of the relaxation rate is preferably 20%, more preferably 15%, and still more preferably 10%. If it exceeds 20%, sag may occur in the tenter, and production may become difficult.

In order to improve the bonding strength with respect to the sealant film or the printed layer, corona treatment or flame treatment may be applied to the surface of the laminated stretched polyamide film and/or the surface of the subsequent modified layer. In addition, in order to increase the bonding strength between the laminated stretched polyamide film and the adhering modified layer, the surface of the laminated stretched polyamide film on the adhering modified layer side may be subjected to corona treatment or flame treatment.

As a method of forming the adhesive modified layer in the present invention, the following methods can be used: using known coating methods such as gravure method, reverse method, mold method, rod method, and dipping method, including polyester resin, polyamine The coating agent of any one of carbamic acid ester resin and/or polyacrylic resin is applied to the laminated stretched polyamide film.

The coating amount of the aforementioned coating agent is preferably 0.01 g/m ² to 3 g/m ² in terms of solid content relative to the biaxially stretched polyamide film. Furthermore, it is preferable to apply|coat so that it may ^{become 0.04g/m<2>} to 0.5g/m<^2>. If it is the above-mentioned coating amount, sufficient bonding strength between the modified layer and other layers can be obtained, and the adhesion of the films to each other can be suppressed.

The subsequent modified layer in the present invention can be coated with a coating agent on the biaxially stretched polyamide film substrate, or dried after coating the coating agent on the unstretched or uniaxially stretched polyamide film substrate , And heat-fixed after uniaxial extension or biaxial extension as needed. As the drying temperature after the coating agent is applied, drying and heat fixing are performed at 180°C or higher, preferably 200°C or higher, so that the coating film becomes firm and the adhesion between the modified layer and the polyamide film substrate is improved. Subsequent.

In the case of stretching after coating, in order not to impair the extensibility of the coating film, the moisture content of the coating film must be controlled within the range of 0.1% to 2% in the drying after coating. After stretching, drying and heat fixing are performed at 200°C or higher, thereby making the coating film firm, and greatly improving the adhesion between the modified layer and the polyamide film substrate.

The easy-adhesive polyamide film of the present invention thus obtained can prevent the film from being scratched due to the friction and the resulting friction even when the bag-made product is transported when there is friction with the transport package such as corrugated cardboard. Broken bag. In addition, it is possible to prevent the bags from being broken due to bending fatigue due to contact between the bags. In addition, since the water-resistant adhesive strength between the polyamide film and the sealant film is high, it exhibits high bag breaking resistance.

[Characteristics of easy-adhesive polyamide film] The easy-adhesive polyamide film of the present invention is based on the measurement method described in the examples. The torsion bending test using a Gelbo-Frank tester (Gelbo FLex tester) is performed 1000 times at a temperature of 1°C. The number of hole defects is 10 or less. More preferably, it is 5 or less. The smaller the number of pinhole defects after the bending test, the better the bending pinhole resistance. If the number of pinholes is 10 or less, it is possible to obtain a packaging bag that is less likely to produce pinholes even when a load is applied to the packaging bag during transportation.

Furthermore, the easily-adhesive polyamide film of the present invention has a distance of 2900 cm or more in the rubbing resistance pinhole test until pinholes are generated. It is more preferably 3100 cm or more, and still more preferably 3300 cm or more. The longer the distance of pinholes, the better the resistance to rubbing pinholes. If the distance of pinholes is 2900cm or more, it is possible to obtain a packaging bag that is not prone to pinholes even when the packaging bag is rubbed against the corrugated cardboard box during transportation. . The easy-adhesive polyamide film of the present invention is characterized in that it is excellent in both the above-mentioned bending pinhole resistance and rubbing pinhole resistance. The easy-adhesive polyamide film of the present invention having these characteristics is less likely to produce pinholes during transportation, and therefore is extremely useful as a film for packaging.

The heat shrinkage rate of the easily adhesive polyamide film of the present invention at 160°C for 10 minutes is in the range of 0.6% to 3.0% in both the traveling direction (hereinafter referred to as MD direction) and the width direction (hereinafter referred to as TD direction). Preferably it is 0.6% to 2.5%. When the heat shrinkage rate exceeds 3.0%, when heat is applied in subsequent steps such as lamination or printing, curling or shrinkage may sometimes occur. In addition, the lamination strength with the sealant film may become weak. The heat shrinkage rate can be less than 0.6%, but the mechanical properties may become brittle. In addition, productivity deteriorates, so it is not good.

The excellent impact resistance is the characteristic of the biaxially stretched polyamide film. Therefore, the easily adhesive polyamide film of the present invention preferably has an impact strength of 0.7J/15μm or more. The better impact strength is 0.9J/15μm or more.

The easy-adhesive polyamide film of the present invention preferably has a haze value of 10% or less. It is more preferably 7% or less, and still more preferably 5% or less. If the haze value is small, the transparency and gloss are good, so when it is used in a packaging bag, it can achieve beautiful printing and increase the product value. If fine particles are added in order to improve the slidability of the film, the haze value will increase. Therefore, when fine particles are added only to the B layer of the functional layer, the haze value can be reduced.

The easy-adhesive polyamide film of the present invention preferably uses the radiocarbon (C ¹⁴ ) measurement of ASTM D6866-16 to determine the content of biomass-derived carbon (also referred to as the degree of biomass) relative to the polyamide film The entire carbon system in contains 1% to 15%. It is known that carbon dioxide in the atmosphere contains C ^{14 at a fixed ratio (105.5 pMC). Therefore, the C 14} content of plants grown by absorbing carbon dioxide in the atmosphere, such as corn, is also about 105.5 pMC. In addition, it is also known that there is almost no C ^{14 in} fossil fuels. ^{Therefore, by measuring the ratio of C 14} contained in all carbon atoms in polyamide, the ratio of biomass-derived carbon can be calculated.

The laminate strength after bonding the easily adhesive polyamide film of the present invention to the polyethylene-based sealant described in the examples is 4.0 N/15 mm or more. The easy-adhesive polyamide film of the present invention is usually processed into packaging bags after being laminated with a sealant film. If the above-mentioned lamination strength is 4.0N/15mm or more, when the easily adhesive polyamide film of the present invention is used to make packaging bags with various laminated structures, the strength of the sealing portion can be sufficiently obtained, and the A strong packaging bag that is not easy to break. In order to set the lamination strength to 4.0N/15mm or more, the easily adhesive polyamide film of the present invention may be subjected to corona treatment, coating treatment, flame treatment, or the like.

Furthermore, the easy-adhesive polyamide film of the present invention may be subjected to heat treatment or humidity control in order to have good dimensional stability due to its application. In addition, in order to improve the adhesiveness of the film surface, corona treatment, coating treatment, flame treatment, etc., or printing processing, metal or inorganic oxide vapor deposition processing, etc. may be performed. In addition, as the vapor-deposited film formed by the vapor-deposition process, an aluminum vapor-deposited film, a silicon oxide or an aluminum oxide's single or a mixture vapor-deposited film can be preferably used. Furthermore, by coating a protective layer or the like on these vapor-deposited films, it is possible to improve oxygen barrier properties, hydrogen barrier properties, and the like.

After the easy-adhesive polyamide film of the present invention is made into a laminated film laminated with a sealant film, etc., it is processed into bottom sealed bags, side sealed bags, three-sided sealed bags, pillow-shaped bags, standing pouches, Packaging bags such as gusset bags and corner bottom bags. Examples of the sealant film include unstretched linear low-density polyethylene films, unstretched polypropylene films, ethylene-vinyl alcohol copolymer resin films, and the like. The layer structure of the laminate film using the easily adhesive polyamide film of the present invention is not particularly limited as long as the laminate film has the easily adhesive polyamide film of the present invention. In addition, the film used in the laminated film can be either a petrochemical-derived material or a biomass-derived material. In terms of reducing the environmental load, it is preferably formed by polymerizing a biomass-derived material. Polylactic acid, polyethylene terephthalate, polybutylene succinate, polyethylene, polyethylene furandicarboxylate, etc.

As an example of the layer structure of the laminated film of the present invention, if the boundary between the layers is represented by "/", for example: ONY/connect/LLDPE, ONY/connect/CPP, ONY/connect/Al/connect/CPP, ONY /Connect/Al/Connect/LLDPE, ONY/PE/Al/Connect/LLDPE, ONY/Connect/Al/PE/LLDPE, PET/Connect/ONY/Connect/LLDPE, PET/Connect/ONY/PE/LLDPE, PET /Connect/ONY/Connect/Al/Connect/LLDPE, PET/Connect/Al/Connect/ONY/Connect/LLDPE, PET/Connect/Al/Connect/ONY/PE/LLDPE, PET/PE/Al/PE/ONY /PE/LLDPE, PET/Connect/ONY/Connect/CPP, PET/Connect/ONY/Connect/Al/Connect/CPP, PET/Connect/Al/Connect/ONY/Connect/CPP, ONY/Connect/PET/Connect /LLDPE, ONY/connect/PET/PE/LLDPE,ONY/connect/PET/connect/CPP,ONY//Al//PET//LLDPE, ONY/connect/Al/connect/PET/PE/LLDPE, ONY/ PE / LLDPE, ONY / PE / CPP, ONY / PE / Al / PE, ONY / PE / Al / PE / LLDPE, OPP / connection / ONY / connection / LLDPE, ONY / connection / EVOH / connection / LLDPE, ONY / Connect / EVOH / Connect / CPP, ONY / Connect / Aluminum or inorganic oxide vapor deposition PET / Connect / LLDPE, ONY / Connect / Aluminum vapor deposition PET / Connect / ONY / Connect / LLDPE, ONY / Connect / Aluminum vapor deposition PET ／PE／LLDPE, ONY／PE／Aluminum Evaporated PET／PE／LLDPE, ONY／Aluminum Evaporated PET／CPP, PET／Aluminum Evaporated PET／OnY／Ony／LLDPE，CPP／ Connect / ONY / connect / LLDPE, ONY / connect / aluminum vapor deposition LLDPE, ONY / connect / aluminum vapor deposition CPP, etc. In addition, each abbreviation used in the above-mentioned layer structure is as follows. ONY: easy-adhesive polyamide film of the present invention; PET: stretched polyethylene terephthalate film; LLDPE: unstretched linear low density polyethylene film; CPP: unstretched polypropylene film; OPP: stretched polypropylene Film; PE: extruded laminated or unstretched low-density polyethylene film; Al: aluminum foil; EVOH: ethylene-vinyl alcohol copolymer resin; connection: adhesive layer for bonding the films to each other; aluminum or inorganic oxide vapor deposition Evaporated with aluminum or inorganic oxide. [Example]

Next, the present invention will be explained in more detail with examples, but the present invention is not limited to the following examples. In addition, the evaluation of the film was performed by the following measurement method. Unless otherwise specified, the measurement is performed in a measurement room at 23°C and a relative humidity of 65%. (1) Haze value of film A direct-reading haze meter manufactured by Toyo Seiki Seisakusho (Co., Ltd.) was used for measurement in accordance with JIS-K-7105. (2) The thickness of the film Divide into 10 equal parts along the TD direction of the film (for a film with a narrow width, divide into equal parts so as to ensure the width of the measurable thickness), overlap 10 pieces of the film with a thickness of 100mm in the MD direction and cut it out at a temperature of 23 Adjust for more than 2 hours in an environment of ℃ and 65% relative humidity. The thickness measurement at the center of each sample was performed using a thickness measuring instrument manufactured by TESTER SANGYO, and the average value of the measured thickness was defined as the thickness.

(3) The membrane quality The membrane quality obtained is measured ^{by radiocarbon (C 14) shown in ASTM D6866-16 Method B (AMS).} (4) Thermal shrinkage rate of film Except that the test temperature was set to 160° C. and the heating time was set to 10 minutes, the thermal shrinkage rate was measured by the following formula in accordance with the dimensional change test method described in JIS C2318. Heat shrinkage ratio=[(length before treatment-length after treatment)/length before treatment]×100(%) (5) The impact strength of the film was measured using a film impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd. Determination. The measured value is converted for every 15 μm of thickness and expressed in J (Joule)/15 μm. (6) The coefficient of dynamic friction of the film According to JIS-C2151, the coefficient of dynamic friction between the outer surfaces of the film rolls was evaluated under the following conditions. In addition, it was carried out under the conditions that the size of the test piece was 130 mm in width, 250 mm in length, and the test speed was 150 mm/min.

(7) Film resistance to bending and pinholes The number of bending fatigue pinholes was measured by the following method using a Galbo-Frank test machine manufactured by Rigaku Kogyo Co., Ltd. After coating the polyester-based adhesive on the film produced in the example, a linear low-density polyethylene film (L-LDPE film: L4102 manufactured by Toyobo Co., Ltd.) with a thickness of 40 μm was dry-laminated at 40°C. It was aged for 3 days to produce a laminated film. The obtained laminated film was cut into 12 inches × 8 inches, and made into a cylindrical shape with a diameter of 3.5 inches. One end of the cylindrical film was fixed to the fixed head side of the Gelper-Franks testing machine. The other end is fixed on the side of the movable head, and the initial holding interval is set to 7 inches. Perform 1000 bending fatigue tests at a speed of 40 times/min, and count the number of pinholes generated in the laminated film. The bending fatigue test is performed at the first 3.5 inches of the stroke with a twist of 440 degrees, and then 2.5 inches in a straight line. End the total stroke by moving horizontally. In addition, the measurement was performed in an environment of 1°C. The test film was placed on a filter paper (Advantec, No. 50) with the L-LDPE film side of the test film as the lower surface, and the four corners were fixed with CELLOTAPE (registered trademark). Ink (Ink made by PILOT (product number INK-350-blue) diluted 5 times with pure water) was applied on the test film, and spread on one side using a rubber roller. After the unnecessary ink is wiped off, the test film is removed, and the number of ink dots attached to the filter paper is counted.

(8) The friction and pinhole resistance of the film Using a fastness tester (Toyo Seiki Seisakusho), a friction test was performed by the following method to measure the pinhole generation distance. The same laminated film as the one made in the above bending pinhole resistance evaluation was folded in four to make a test sample with sharp corners, using a fastness tester, with amplitude: 25 cm, amplitude speed: 30 times /Min, aggravation: 100g weight, friction on the inner surface of the corrugated cardboard. For the corrugated cardboard system, K280×P180×K210(AF)=(surface material pad×core material×inner surface material pad (type of flute of corrugated cardboard)). The pinhole generation distance is calculated according to the following procedure. The longer the pinhole generation distance, the better the rubbing pinhole resistance. First, a friction test was carried out at a distance of 2500 cm with an amplitude of 100 times. When there is no pinhole, increase the number of amplitude 20 times and perform a friction test with a distance of 500cm. In addition, when no pinholes were generated, a friction test was performed by increasing the number of amplitudes 20 times and a distance of 500 cm. Repeat this operation to mark the distance where the pinhole is generated and set it as level 1. When pinholes were generated at a distance of 2500 cm at 100 times of amplitude, the friction test was performed by reducing the number of times of amplitude 20 times at a distance of 500 cm. In addition, in the case of pinholes, a friction test was performed by reducing the number of amplitudes 20 times and a distance of 500 cm. This operation is repeated and the distance where no pinhole is generated is marked with ○ and set to level 1. Next, as level 2, in the case where level 1 is ○ at the end, the friction test is performed by increasing the number of amplitudes by 20 times. If no pinholes are generated, ○ is marked, and if pinholes are generated, the friction test is marked ×. In the case of x at the end in level 1, the friction test is performed by reducing the number of amplitudes by 20 times. If no pinholes are generated, mark ○, and if pinholes are generated, mark ×. Furthermore, as level 3 to level 20, when the previous level was ○, the friction test was performed by increasing the number of amplitudes by 20 times. If no pinholes were generated, ○ was marked, and if pinholes were generated, the friction test was marked ×. In the case where the previous level was ×, the friction test was performed by reducing the number of amplitudes by 20 times. If no pinholes were generated, mark ○, and if pinholes were generated, mark ×. This operation is repeated to mark ○ or × for level 3 to level 20. For example, the results shown in Table 1 were obtained. Take Table 1 as an example to illustrate how to calculate the pinhole distance. Count the number of trials of ○ and × for each distance. Set the distance with the largest number of trials to the central value, and set the coefficient to zero. When the distance is longer than the central value, set the coefficients to +1, +2, +3 every 500cm. When the distance is shorter than the central value, set the coefficients to -1, -2,-every 500cm. 3... In all the tests from level 1 to level 20, compare the number of tests with no holes and the number of tests with holes. For the cases of A and B below, use various formulas to calculate the friction pinhole generation distance. A: In all the tests, the number of tests without holes is more than the number of tests with holes. The distance generated by the friction pinhole = the central value + 500 × (Σ (the coefficient × the number of tests without holes) / the number of tests without holes) + 1/2) B: In all tests, the number of tests without holes did not reach the number of tests with holes. The distance generated by the friction pinhole = central value + 500 × (Σ (factor × number of tests with holes) / number of tests with holes)-1/2)

[Table 1]

(9) Relative to the lamination strength of polyethylene sealant The laminated film produced in the same manner as the method described in the description of the bending pinhole resistance evaluation was cut into short strips with a width of 15 mm × a length of 200 mm, and one end of the laminated film was placed on the biaxially stretched polyamide The interface between the film and the linear low-density polyethylene film was peeled off using Autograph (manufactured by Shimadzu Corporation) at a temperature of 23°C, a relative humidity of 50%, a stretching speed of 200mm/min, and a peeling angle of 90°. The lamination strength was measured 3 times in the MD direction and the TD direction, and the average value of the 3 times was evaluated.

(10) Water-resistant lamination strength (lamination strength under water adhesion conditions) When measuring the lamination strength of (9), the lamination strength was measured while dripping water with a dropper at the peeling interface of the short strip-shaped laminated film. The MD direction and the TD direction were measured 3 times and the average value was evaluated.

(11) Film formation stability during casting The process of extruding the molten resin into a film from a T-die by visual observation, casting on a cooling roll and cooling to obtain an unstretched film, evaluated the film forming stability in the following manner. ○: Film formation is stable and a homogeneous unstretched film is obtained. △: Film formation is slightly unstable, and variations in the width of the unstretched film are observed, but biaxial stretching is possible. X: The film formation was unstable and the stretched film was not homogeneous, so a biaxial stretched film was not obtained. (12) The generation cycle of thermal degradation products generated at the die lip exit After cleaning the die lip, start the film formation, and observe the time until thermal deterioration occurs on the die lip.

(13) The relative viscosity of the raw material polyamide. Dissolve 0.25g of polyamide in a 25ml volumetric flask with a concentration of 1.0g/dl using 96% sulfuric acid, and measure the obtained polyamide solution at 20°C. Relative viscosity. (14) The melting point of the raw material polyamide is based on JIS K7121 using the SSC5200 differential scanning calorimeter manufactured by Seiko Instruments, in a nitrogen atmosphere, in a sample weight: 10 mg, heating starting temperature: 30°C, heating rate: 20 The measurement was performed under the condition of °C/min, and the endothermic peak temperature (Tmp) was determined as the melting point. (15) Coating amount of adhesive modified layer: Cut the biaxially oriented polyamide film into an area of 10cm×10cm, and wipe the film with a cloth impregnated with a mixed organic solvent of methyl ethyl ketone/toluene=1/1 Using a precision balance (AUW120D manufactured by Shimadzu Corporation) to measure the weight before and after wiping on the adhesively modified layer of the film. ^{The coating amount (g/m 2} ) was calculated by converting the measured weight difference into per square meter.

[Example 1-1] Using a device composed of an extruder and a 380mm wide T-die, extrude the molten resin composition from the T-die into a film, cast it on a cooling roll with a temperature of 20°C, and make it electrostatically adhered. Unstretched film with a thickness of 200μm. Resin composition: 97 parts by mass of polyamide 6 (manufactured by Toyobo Co., Ltd., relative viscosity 2.8, melting point 220°C), and polyamide 11 (manufactured by Arkema, relative viscosity 2.5, melting point 186°C, biomass 100 %) 3.0 parts by mass, porous silica particles (manufactured by FUJI SILYSIA CHEMICAL Co., Ltd., average particle size 2.0 μm, pore volume 1.6 ml/g) 0.45 parts by mass, and fatty acid bisamide (Kyoeisha Chemical Co., Ltd.) The produced ethylene distearate) is a resin composition composed of 0.15 parts by mass. The obtained unstretched film was introduced into a roll stretcher, and after being stretched 1.73 times in the MD direction at 80°C using the difference in the peripheral speed of the rolls, it was further stretched 1.85 times at 70°C. Then, the following coating liquid (A) was applied to the uniaxially stretched film by a roll coater, and then it was continuously introduced into the tenter stretcher while being dried by warm air at 70°C. After preheating at 110°C, stretch 1.2 times at 120°C along the TD direction, 1.7 times at 130°C, and 2.0 times at 160°C. After heat-fixing at 215°C, 7% relaxation treatment at 215°C, and then Take up to obtain a biaxially stretched polyamide film laminated with an adhesive modified layer (AEG). The evaluation results of the obtained easily adhesive polyamide film are shown in Table 2.

[Coating solution (A): Aqueous dispersion of acrylic graft copolymer polyester] In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux cooler, 466 parts by mass of dimethyl terephthalate, 466 parts by mass of dimethyl isophthalate, 401 parts by mass of neopentyl glycol, and ethylene dichloride were added 443 parts by mass of alcohol and 0.52 parts by mass of tetra-n-butyl titanate were transesterified at 160°C to 220°C for 4 hours. Then, 23 parts by mass of fumaric acid were added, and the temperature was raised from 200°C to 220°C over 1 hour to proceed the esterification reaction. Then, the temperature was raised to 255°C, and the reaction system was gradually reduced in pressure, and then reacted while stirring under a reduced pressure of 0.2 mmHg for 1 hour and 30 minutes to obtain a polyester. The obtained polyester is light yellow and transparent, the glass transition temperature is 60°C, and the weight average molecular weight is 12,000. The composition obtained by NMR (Nuclear Magnetic Resonance) measurement etc. is as follows. ・Dicarboxylic acid component Terephthalic acid 48 mol% Isophthalic acid 48 mol% Fumaric acid 4 mol% ・Diol component Neopentyl glycol 50 mole% Ethylene glycol 50 mol% Into a reactor equipped with a stirrer, a thermometer, a reflux device, and a quantitative dropping device, add 75 parts by mass of the polyester resin, 56 parts by mass of methyl ethyl ketone, and 19 parts by mass of isopropanol, and heat at 65°C , Stir to dissolve the resin. After the resin is completely dissolved, a mixture of 17.5 parts by mass of methacrylic acid and 7.5 parts by mass of ethyl acrylate, and 1.2 parts by mass of azobisdimethylvaleronitrile are dissolved in 25 parts by mass of methyl ethyl ketone, and the obtained The solution was added dropwise to the polyester solution at 0.2 ml/min, and stirring was continued for 2 hours after the dropwise addition was completed. After sampling (5 g) for analysis from the reaction solution, 300 parts by mass of water and 25 parts by mass of triethylamine were added to the reaction solution and stirred for 1 hour to adjust the dispersion of the grafted polyester. Then, the temperature of the obtained dispersion was raised to 100°C, and methyl ethyl ketone, isopropanol, and excess triethylamine were distilled off by distillation to obtain an aqueous dispersion of copolyester.

The obtained dispersion was white with an average particle size of 300 nm and a type B viscosity of 50 centipoise at 25°C. After adding 1.25 g of heavy water to 5 g of this dispersion so that the solid content concentration became 20% by mass, DSS (Disuccinimidyl suberate; disuccinimidyl suberate) was added, and 125 MHz13C-NMR was measured. The half-value width of the signal (160ppm-175ppm) of the carbonyl carbon of the polyester main chain is ∞ (no signal is detected), and the half-value width of the signal (181ppm to 186ppm) of the carbonyl carbon of the grafted part of methacrylic acid is 110Hz . Take a sample at the end of the grafting reaction, dry the sampled solution under vacuum at 100°C for 8 hours, and measure the acid value of the solid content obtained by drying and the grafting efficiency of polyester (measured by NMR) ), and the determination of the molecular weight of the grafted part by hydrolysis. The acid value of the solid content is 2300eq./10 ⁶ g. In the 1H-NMR measurement, no signal derived from fumaric acid (δ=6.8ppm-6.9ppm, doublet) was detected at all, so it was confirmed that the grafting efficiency of the polyester was 100%. The molecular weight of the grafted part is a weight average molecular weight of 10,000. Then, the aqueous dispersion obtained in the above-mentioned manner was diluted with water so that the solid content concentration became 5 mass %, and the coating liquid (A) was obtained.

[Example 1-2 to Example 1-9] The resin composition of the raw material was changed as shown in Table 2, except that the same method as in Example 1-1 was used to obtain a biaxially stretched polyamide film having an adhesive modified layer (AEG). Table 2 shows the evaluation results of the obtained easily adhesive polyamide film. Among them, in Examples 1-6 and 1-7, the aforementioned coating liquid (B): an aqueous dispersion of polyurethane resin was used as the coating liquid to obtain a laminated adhesive modified layer ( PU) Easy-adhesive polyamide film. [Coating Solution (B): Aqueous Dispersion of Polyurethane Resin] (A) Preparation of polyurethane and aqueous dispersion: using adipic acid as a dicarboxylic acid component and 1,4-butanediol 60 mol% (diol component) as a diol component, And 40 mol% of propylene oxide (1 mol) adduct of bisphenol A to obtain a polyester (polyester polyol) with a Tg of -5°C. Toluene diisocyanate is allowed to act on the polyester to obtain a urethane polymer. Using this urethane polymer as a prepolymer, 1,6-hexanediol acts to extend the chain, and the amino carboxylate is reacted with the terminal to obtain a water-insoluble and water-dispersible polyamine group Formate. The obtained polyurethane was dispersed in hot water while stirring to obtain a 25% aqueous dispersion. The aqueous dispersion of the polyurethane is added to an equivalent mixed liquid of ion-exchanged water and isopropanol so that the solid content becomes 5% by mass, and diluted to obtain a coating liquid (B).

[Comparative Example 1-1 to Comparative Example 1-6] A biaxially stretched polyamide film was obtained by the same method as in Example 1-1 except that the resin composition of the raw materials shown in Table 2 was used without forming an adhesive modified layer. In order to make the adhesiveness with respect to the sealant film good, the surface of the film is subjected to corona discharge treatment after heat-fixing treatment and relaxation treatment are performed. The evaluation results are shown in Table 2. Among them, in Comparative Example 1-4, the molten resin could not be stably extruded into a film form from the T-die, and a homogeneous unstretched film could not be obtained, so biaxial stretching could not be performed.

[Table 2]

As shown in Table 2, the film of the example obtained a film with good bending pinhole resistance and rubbing pinhole resistance. In addition, the haze is low, the transparency is good, the impact strength is also strong, and the lamination strength relative to the sealant film is also high, and it is excellent as a packaging film. In addition, due to the presence of the adhesive modified layer, the laminate strength, especially the water-resistant laminate strength, is excellent. The biaxially stretched polyamide film of Comparative Example 1-1 and Comparative Example 1-2 without modified bending pinhole resistance material and the biaxially stretched polyamide film of Comparative Example 1-3 with too little content of polyamide 11 The amide film has poor bending pinhole resistance. In Comparative Example 1-4, since the content of the polyamide 11 was too high, the molten resin could not be stably extruded into a film from the T-die, so a homogeneous unstretched film could not be obtained, and a biaxially stretched polyamide film could not be obtained. In Comparative Examples 1-5, the previously used polyamide elastomer was used as the modified bending pinhole resistance material. As a result, although the bending pinhole resistance was good, the rubbing pinhole resistance was poor. In addition, it has the following disadvantages: Deteriorated products tend to adhere to the mold during long-term production, and long-term continuous production cannot be realized. In Comparative Examples 1-6, the biaxially stretched polyamide film of the present invention was not provided with an adhesive modified layer, and instead, corona treatment was performed to improve the adhesiveness. Although the bending pinhole resistance and rubbing pinhole resistance are good, the lamination strength and water resistance lamination strength are low.

[Example 2-1] Except that the heat-fixing treatment temperature and the relaxation treatment temperature were set to 218°C, in the same manner as in Example 1-1, an easily adhesive biaxially stretched polyamide film having an adhesive modified layer (AEG) was obtained. Table 3 shows the evaluation results of the obtained easily adhesive polyamide film.

[Example 2-2 to Example 2-10 and Comparative Example 2-1 to Comparative Example 2-5] The resin composition of the raw material was changed as shown in Table 3, except that the same method as in Example 2-1 was used to obtain an easy-adhesive polyamide film having an adhesive modified layer. Table 3 shows the evaluation results of the obtained easily adhesive polyamide film. In addition, as polyamide 410, polyamide 610, and polyamide 1010, which are polyamide resins composed of at least a part of biomass-derived raw materials, the following polyamide resins were used, respectively. Polyamide 410: (manufactured by DSM, ECOPaXX Q150-E, melting point 250°C, biomass 71%) Polyamide 610: (manufactured by Arkema, RilsanS SMNO, melting point 222°C, biomass 62.5%) Polyamide 1010: (manufactured by Arkema, RilsanT TMNO, melting point 202°C, biomass 50%) Among them, in Examples 2-7, the aforementioned coating liquid (B): an aqueous dispersion of polyurethane resin was used as the coating liquid to obtain easy adhesion with a laminated adhesive modified layer (PU) Polyamide film. The heat fixation treatment and relaxation treatment of Example 2-6 and Comparative Example 2-2 were performed at 210°C. In addition, in Comparative Example 2-4, the molten resin could not be stably extruded into a film form from the T-die, and a homogeneous unstretched film could not be obtained, so biaxial stretching could not be performed.

[table 3]

As shown in Table 3, the film of the example obtained a film having both good bending pinhole resistance and rubbing pinhole resistance. In addition, the haze is low, the transparency is good, the impact strength is also strong, and the lamination strength with the sealant film is also high, and it is excellent as a packaging film. Comparative example 2-1 and comparative example 2-2 do not contain at least a part of the raw material that has the effect of modified bending pinhole resistance, a biaxially stretched polyamide film derived from a bio-derived polyamide resin and comparative example 2 -3 The content of polyamide 11 is too small, and the biaxially stretched polyamide film has poor bending pinhole resistance. In Comparative Example 2-4, since the content of polyamide 11 was too high, the molten resin could not be stably extruded into a film from the T-die, a homogeneous unstretched film could not be obtained, and a biaxially stretched polyamide film could not be obtained. Comparative Example 2-5 used the previously used polyamide elastomer as a modified bending pinhole resistance material. As a result, although the bending pinhole resistance was good, the rubbing pinhole resistance was poor. In addition, it has the following shortcomings: Deteriorated products tend to adhere to the mold during long-term production, and long-term continuous production cannot be realized.

[Example 3-1] Using a device composed of 2 extruders and a 380mm wide co-extrusion T-die, the molten resin is extruded from the T-die into a film by using the feed block method to laminate with the B-layer/A-layer/B-layer composition Shape, cast on a cooling roll whose temperature is adjusted to 20°C and make it electrostatically close to obtain an unstretched film with a thickness of 200μm. The resin compositions of the A layer and the B layer are as follows. Resin composition constituting layer A: 97 parts by mass of polyamide 6 (manufactured by Toyobo Co., Ltd., relative viscosity 2.8, melting point 220°C), and polyamide 11 (manufactured by Jisheng Company, relative viscosity 2.5, melting point 186°C) , Biomass 100%) 3.0 parts by mass of a polyamide resin composition. The resin composition constituting the B layer: 95 parts by mass of polyamide 6 (manufactured by Toyobo Co., Ltd., relative viscosity 2.8, melting point 220°C), and polyamide MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity 2.1, Melting point: 237°C) 5.0 parts by mass, porous silica particles (manufactured by FUJI SILYSIA CHEMICAL Co., Ltd., average particle size 2.0 μm, pore volume 1.6 ml/g) 0.54 parts by mass, and fatty acid bisamide (Kyoeisha Chemical Co., Ltd.) Co., Ltd. manufactures a resin composition composed of 0.15 parts by mass of ethylene distearate). In addition, regarding the thickness of the biaxially stretched polyamide film, the total thickness is 15 μm, the thickness of the base layer (layer A) is 12 μm, and the thickness of the front and back functional layers (layer B) is 1.5 μm, respectively. Adjust the composition of the feed block and the ejection volume of the extruder. The obtained unstretched film was introduced into a roll stretcher, and after being stretched 1.73 times in the MD direction at 80°C using the difference in the peripheral speed of the rolls, it was further stretched 1.85 times at 70°C. Then, after coating the above-mentioned coating liquid (A) on the uniaxially stretched film with a roll coater, it was continuously introduced into the tenter stretcher at 110°C while being dried by warm air at 70°C. After preheating, stretch 1.2 times at 120°C in the TD direction, 1.7 times at 130°C, and 2.0 times at 160°C. After heat setting treatment at 215°C, 7% relaxation treatment at 215°C, and then coiling A biaxially stretched polyamide film laminated with an adhesive modified layer (AEG) was obtained. Table 4 shows the evaluation results of the obtained easily adhesive polyamide film.

[Example 3-2 to Example 3-9] Except changing the resin compositions of the A layer and the B layer as shown in Table 4, the same method as in Example 3-1 was used to obtain a biaxially stretched polyamide film having an adhesive modified layer. Table 4 shows the evaluation results of the obtained easily adhesive polyamide film. Among them, in Examples 3-8 and 3-9, the aforementioned coating liquid (B): an aqueous dispersion of polyurethane resin was used as the coating liquid to obtain a laminated adhesive modified layer ( PU) Easy-adhesive polyamide film. [Comparative Example 3-1 to Comparative Example 3-5] The resin composition using the raw materials shown in Table 4, in order to improve the adhesion, instead of forming an adhesive modified layer, is the side that will be dry-laminated with the linear low-density polyethylene film after the heat-fixing treatment and the relaxation treatment The surface of the film is subjected to corona discharge treatment. The evaluation results are shown in Table 4. Among them, in Comparative Example 3-3, since the content of the polyamide 11 was too high, the molten resin could not be stably extruded into a film from the T-die, and a homogeneous unstretched film could not be obtained, so biaxial stretching could not be performed.

[Table 4]

As shown in Table 4, the film of the example obtained a film with good bending pinhole resistance and rubbing pinhole resistance. In addition, the haze is low, the transparency is good, and the sliding properties are also good. The impact strength is also strong, and the lamination strength with the sealant film is also high, and it is excellent as a packaging film. In addition, due to the presence of the adhesive modified layer, the water-resistant laminate strength is excellent. In addition, according to the values of the haze and dynamic friction coefficient of the films obtained in Examples 3-2, 3-6, and 3-7, it can be seen that if the B layer (functional layer) contains fine particles and an organic lubricant , And polyamide MXD6, a biaxially stretched polyamide film with excellent transparency and sliding properties can be obtained. The biaxially stretched polyamide film of Comparative Example 3-1 without polyamide 11 and the biaxially stretched polyamide film of Comparative Example 3-2 with a low content of polyamide 11 have poor bending pinhole resistance. In addition, since there is no adhesive modified layer, the water-resistant laminate strength is also low. In Comparative Example 3-3, since the content of polyamide 11 was too high, the molten resin could not be stably extruded into a film from the T-die, and therefore a homogeneous unstretched film could not be obtained, and a biaxially stretched polyamide film could not be obtained. In Comparative Example 3-4, the previously used polyamide elastomer was used as the modified bending pinhole resistance material. As a result, although the bending pinhole resistance was good, the rubbing pinhole resistance was poor. In addition, it has the following shortcomings: Deteriorated products tend to adhere to the mold during long-term production, and long-term continuous production cannot be realized. In Comparative Examples 3-5, the biaxially stretched polyamide film of the present invention was not provided with an adhesive modified layer, and instead corona treatment was performed to improve the adhesiveness. Although the bending pinhole resistance and rubbing pinhole resistance are good, the water-resistant laminate strength is low.

[Example 4-1] Except that the heat-fixing treatment temperature and the relaxation treatment temperature were set to 218°C, in the same manner as in Example 3-1, an easily adhesive biaxially stretched polyamide film having an adhesive modified layer (AEG) was obtained. Table 5 shows the evaluation results of the obtained easily adhesive polyamide film.

[Example 4-2 to Example 4-11 and Comparative Example 4-1 to Comparative Example 4-7] Except changing the film forming conditions such as the resin composition of the layer A and the layer B and the heat setting temperature as shown in Table 5, the same method as in Example 4-1 was used to obtain an easy-adhesive polyamide film. Table 5 shows the evaluation results of the obtained easily adhesive polyamide film. Among them, in Examples 4-8, the aforementioned coating liquid (B): an aqueous dispersion of polyurethane resin was used as the coating liquid to obtain easy adhesion with a laminated adhesive modified layer (PU) Polyamide film. The heat fixation treatment and relaxation treatment of Example 4-6 and Comparative Example 4-2 were performed at 210°C. In addition, in Comparative Example 4-4, because the content of the polyamide 11 in the base layer was too high, the molten resin could not be stably extruded from the T-die into a film, and a homogeneous unstretched film could not be obtained. Axis extension.

[table 5]

As shown in Table 5, the film of the example obtained a film having both good bending pinhole resistance and rubbing pinhole resistance. In addition, the haze is low, the transparency is good, the impact strength is also strong, the lamination strength with the sealant film and the water-resistant lamination strength are also high, and it is excellent as a packaging film. In Comparative Example 4-1 and Comparative Example 4-2, at least a part of the raw material that does not have the effect of modified bending pinhole resistance is derived from a polyamide film of bio-based polyamide resin and Comparative Example 4-3 If the content of polyamide 11 is too small, the polyamide film has poor bending pinhole resistance. In Comparative Example 4-4, since the content of polyamide 11 was too high, the molten resin could not be stably extruded into a film from the T-die, a homogeneous unstretched film could not be obtained, and a biaxially stretched polyamide film could not be obtained. In Comparative Example 4-5, since the thickness and thickness ratio of the A layer were small, the film had poor bending pinhole resistance. In Comparative Examples 4-6, since the amount of the polyamide 6 resin of the B layer was small, the film had poor bending pinhole resistance and rubbing pinhole resistance. Comparative Examples 4-7 used the previously used polyamide elastomer as the modified bending pinhole resistance material. As a result, although the bending pinhole resistance was good, the rubbing pinhole resistance was poor. In addition, it has the following shortcomings: Deteriorated products tend to adhere to the mold during long-term production, and long-term continuous production cannot be realized. [Industry Availability]

The easy-adhesive polyamide film of the present invention is excellent in impact resistance, bending pinhole resistance and friction pinhole resistance at the same time, so it can be preferably used for packaging materials such as food packaging. In addition, due to the strong lamination strength and water-resistant lamination strength, various packaging bags that are not easily broken during transportation or boiling treatment can be provided. Furthermore, it is a carbon-neutral film using a resin polymerized from raw materials derived from biomass that existed in the original local surface, which can reduce the environmental load in terms of less impact on the increase and decrease of carbon dioxide on the surface. .

1: The head of the fastness testing machine 2: Corrugated cardboard 3: Backing paper for sample retention 4: Fold the film sample with 4 folds 5: Friction amplitude direction

[Fig. 1] A schematic diagram of an evaluation device for rubbing resistance and pinhole resistance.

Claims (8)

An easy-adhesive polyamide film, which has an adhesive modification layer on at least one side of a biaxially stretched polyamide film. The biaxially stretched polyamide film contains 99% to 70% by mass of polyamide 6 resin and At least a part of the raw material is derived from 1% to 30% by mass of biomass polyamide resin, and the aforementioned subsequent reforming layer is made of polyester resin with a ^{coating amount of 0.01 g/m 2} to 3 g/m ^{2 in terms of solid content} , Polyurethane resin, and/or polyacrylic resin. An easy-adhesive polyamide film, which has an adhesive modification layer on at least one side of a biaxially stretched polyamide film, and the aforementioned biaxially stretched polyamide film is on at least one side of the following substrate layer A layer The following functional layer B layer is laminated, and the aforementioned subsequent modified layer is composed of polyester resin, polyurethane resin, and/ ^{or a coating amount of 0.01 g/m 2} to 3 g/m ^{2 in terms of solid content.} Or composed of any one of polyacrylic resins; The base layer A layer contains 99% to 70% by mass of polyamide 6 resin and at least a part of the raw material is derived from biomass resin 1% to 30% by mass , The functional layer B layer contains 70% by mass or more of polyamide 6 resin. The easily-adhesive polyamide film as described in claim 1 or 2, wherein the content of biomass-derived carbon measured ^{by radiocarbon C 14 relative to all carbon in the biaxially stretched polyamide film is} 1% to 15%. The easy-adhesive polyamide film described in claim 1 or 2, wherein at least a part of the raw material is derived from biomass polyamide resin selected from polyamide 11, polyamide 410, polyamide 610, and At least one polyamide resin in the group consisting of polyamide 1010. The easy-adhesive polyamide film described in claim 1 or 2, which satisfies the following (a) and (b); (a) The number of Galbo pinhole defects when the torsion and bending test using the Galbo-Franks testing machine is carried out at a temperature of 1°C for 1000 times is less than 10; (b) In the rubbing resistance pinhole test, the distance until pinholes are generated is 2900 cm or more. The easy-adhesive polyamide film described in claim 1 or 2 has a lamination strength of 4.0N/15mm or more after being bonded to a polyethylene-based sealant film. A laminated film which is laminated with a sealant film on an easily adhesive polyamide film as described in claim 1 or 2. A packaging bag that uses the laminated film as described in claim 7.

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