JP2003039615A - Polyamide laminated film and packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide laminated film having excellent slip properties, transparency and impact resistance being film quality necessary as a packaging film and a packaging material, having good processability in a processing process for printing, lamination or the like when used as various packaging materials, also excellent in the sealability or hermetic sealability of a laminated packaging material and fitted to a packaging use, and the packaging material. SOLUTION: The laminated film is constituted by laminating an easy slip layer, wherein the maximum height (SRmax) of the surface roughness of the film constituting the outermost layer is not less than 1.30 μm, on a base layer comprising a polyamide polymer and the mutual coefficient of static friction under a 23 deg.C/50% RH environment of the easy slip layer of the laminated film is not more than 0.45.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide-based laminated film and a packaging material, particularly for printing, laminating and the like when it is used as a packaging material for food packaging etc. because of its excellent slipperiness, transparency and impact resistance. The present invention relates to a polyamide-based laminated film and a packaging material which have good processability and also have excellent sealing suitability and hermeticity for a laminated film bag product and the like, and which are suitable for various packaging applications.

[0002]

2. Description of the Related Art An unstretched film or a stretched film made of a polyamide-based polymer represented by nylon 6 or nylon 66 is
It has excellent strength and gas barrier properties, and especially when used for food packaging, it is effective in preventing alteration of the contents and in preventing bag breakage due to vibration and shock during transportation, so the film has a low melting point. It is used as a packaging material obtained by laminating a thermoplastic film, and is widely used as various packaging materials through processes such as bag making and filling of contents.

[0003]

However, the unstretched film or stretched film made of the above polyamide polymer has a slipperiness as compared with a film made of another polymer component such as a polyolefin polymer or a polyester polymer. Unfortunately, there are many process troubles due to wrinkles in the process of printing and laminating the film, and in the process of bag-making and filling the contents of the packaging material in which the film is laminated with a low melting point thermoplastic film. However, there are problems such as an increase in the incidence of defective products and a decrease in operability.

In order to solve the above problems, a large amount of inorganic fine particles or an organic lubricant is added to a polyamide polymer film, or a coating liquid containing inorganic fine particles is added to the polyamide polymer film. Although coating of a film has been carried out, the transparency of the film is deteriorated and the manufacturing process of the film is complicated, and the quality and operability have not reached a satisfactory level.

The present invention solves the problems of the above-mentioned conventional unstretched film or stretched film made of a polyamide-based polymer, and has the film quality required as a packaging film and a packaging material, that is, slipperiness, transparency and resistance. It has excellent impact resistance, and when used as various packaging materials, it has good processability in the processing steps such as printing and laminating, and also has excellent sealing suitability and sealing property for laminated packaging materials. It is an object to provide a suitable polyamide-based laminated film and packaging material.

[0006]

In order to achieve the above object, the polyamide-based laminated film of the present invention comprises a base layer made of a polyamide-based polymer, and a maximum height of surface roughness of the film surface constituting the outermost layer ( SRmax) is 1.30 μm
A laminated film obtained by laminating the easy-slip layers as described above,
And, between the surfaces of the laminated film on the easy sliding layer side, 23 ° C.,
The static friction coefficient under a 50% RH environment is 0.45 or less.

In this case, the polyamide polymer forming the base layer and / or the slipping layer may contain 0.01 to 0.40% by weight of fatty acid amide and / or fatty acid bisamide.

In this case, the melting point of the polyamide polymer constituting the base layer of the polyamide laminate film is 30
It is possible to form a thermoplastic film layer having a melting point lower than 0 ° C.

Further, in this case, the adhesion modifying layer can be formed on the polyamide-based laminated film.

Further, in this case, the gas barrier layer can be formed on the polyamide laminated film.

Furthermore, in this case, the polyamide-based laminated film can be used as a packaging material.

The polyamide-based laminated film and packaging material of the present invention are excellent in slipperiness, transparency and impact resistance, and have good processability in processing steps such as printing and laminating. Since it has excellent sealing suitability and sealing property, it can be effectively used as various packaging materials.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The polyamide-based laminated film and packaging material of the present invention will be described in detail below.

As the polyamide polymer used in the present invention for forming the base layer and / or the slipping layer, nylon 6, nylon 6.6, nylon 12, nylon 6/10 is used.
Other examples include aliphatic polyamides such as nylon 6/6/6, nylon 6/6/10, nylon 6.6 / 6/10, and ε-caprolactam,
A small amount of a copolymer of this with a nylon salt of hexamethylenediamine and isophthalic acid or a nylon salt of metaxylylenediamine and adipic acid, a hard segment composed of a polyamide component and a polyoxyalkylene glycol component A polyamide block copolymer composed of soft segments constituted, further, metaxylylenediamine, or mixed xylylenediamine composed of metaxylylenediamine and paraxylylenediamine as a main diamine component, having 6 to 6 carbon atoms.
12, a metaxylylene group-containing polyamide polymer containing an α, ω-aliphatic dicarboxylic acid as a main dicarboxylic acid component,
Also, aromatic polyamide and mixed polymers thereof can be used.

In the polyamide-based laminated film and the packaging material of the present invention, the maximum height (SRmax) of the surface roughness of the film surface constituting the outermost layer of the base layer made of the polyamide-based polymer is 1.30 μm or more. Laminate an easy slip layer. Maximum height of surface roughness (SRmax) is 1.30
If it is less than μm, sufficient slipperiness cannot be obtained. Such a slipping layer is laminated on one surface or both surfaces of the base layer in the polyamide-based laminated film and the packaging material.

A certain maximum height (SRma) on the film surface
Examples of the method for forming the surface roughness having x) include a solvent treatment method using a solvent such as toluene and trichlorethylene and a method of sandblasting the film surface, but the industrial productivity and quality stability of the film are considered. Then, a method of forming an easy-slip layer having a specific maximum height of surface roughness by adding inorganic fine particles to a polyamide polymer is desirable.

In this case, examples of the inorganic fine particles added to the polyamide polymer include calcium carbonate, silicon dioxide, barium sulfate, magnesium oxide, alumina, zeolite, and the like. It is also possible to use a coating-treated product. The shape of these inorganic fine particles is spherical, cubic, columnar, conical, disk-shaped, or amorphous, and can be used depending on the intended use of the film.

The average particle diameter of these inorganic fine particles is the maximum height of the required surface roughness of the film surface (SRma).
It can be set according to x) and is not particularly limited, but when the polyamide-based laminated film and the packaging material of the present invention are used for packaging, the average particle size is usually 1.0 to
It is preferable to use one having a thickness of 5.0 μm.

The amount of the inorganic fine particles added to the polyamide polymer can be set according to the required maximum surface roughness (SRmax) of the film surface, and is not particularly limited. However, considering the slipperiness and transparency, and further the increase in filter pressurization in the melt extrusion step, it can be said that the range of 5.0% by weight or less is desirable.

The method of adding the inorganic fine particles to the polyamide polymer is to add the fine particles during the polymerization or when the fine particles are melted in an extruder to form a master batch. It can be carried out by a known method such as addition to the coalescence.

The polyamide-based laminated film of the present invention has, on at least one surface thereof, an easy-sliding layer having a maximum surface roughness (SRmax) of 1.30 μm or more on the film surface, and the polyamide-based laminated film. The coefficient of static friction between the surfaces of the film on the easy sliding layer side at 23 ° C. and 50% RH is 0.45 or less, and the film has good slidability and can improve processability in printing or laminating. it can.

Fatty acid amides and fatty acid bisamides preferably contained in the polyamide polymer constituting the base layer and / or the slipping layer of the polyamide laminated film of the present invention include erucic acid amide, stearic acid amide and ethylene bisstearin. Examples thereof include acid amide and ethylenebisoleic acid amide.

In this case, the amount of the fatty acid amide and / or the fatty acid bisamide contained in the polyamide polymer constituting the base layer and / or the slippery layer is preferably 0.0
1 to 0.40% by weight, more preferably 0.05
Is about 0.20% by weight. When the content of the fatty acid amide and / or the fatty acid bisamide is less than 0.01% by weight, the effect of improving the slipperiness is small, and when the content exceeds 0.40% by weight, the transparency becomes insufficient and the surface of the film may be deteriorated over time. Bleeding may cause unevenness on the surface, which is not preferable in terms of quality.

In the present invention, the polyamide-based laminated film in which the easy-slip layer constitutes the outermost layer has a melting point of 30 ° C. or more from the melting point of the polyamide-based polymer forming the base layer on the side opposite to the easy-slip layer. By forming a thermoplastic film layer having a low melting point, a polyamide-based laminated film exhibiting excellent heat-sealing properties can be obtained. In addition, when the easy-sliding layer is laminated on both surfaces of the base layer, by forming a thermoplastic film layer on the surface of one of the easy-sliding layer, it is possible to obtain a polyamide-based laminated film exhibiting excellent heat sealability. it can. As the thermoplastic film layer used here having a melting point of 30 ° C. or more lower than the melting point of the polyamide-based polymer constituting the base layer, an unstretched sealant film in an ordinary laminate film is used, and examples thereof include polypropylene film and polyethylene. Examples thereof include a film and a linear low density polyethylene film.

The adhesive performance can be improved by modifying the surface of at least one of the polyamide-based laminated films of the present invention. Means for such surface modification is not particularly limited, and examples thereof include corona discharge treatment, flame treatment, low temperature plasma treatment, glow discharge treatment, and the like, but the most practical one is a polyamide-based laminated film. It is a method of forming an adhesion modifying layer on the surface of at least one film.

Examples of the adhesive property-improving layer formed on the polyamide-based laminated film of the present invention include polyester-based resins, polyacrylic-based resins, polyurethane-based resins, etc., among which polyester-based resins are particularly preferable, It is preferable to use a graft copolymer resin obtained by modifying a polymerized polyester with an acrylic acid component, a maleic anhydride component or the like. Typical examples of the copolyester in this case include a crystalline or amorphous thermoplastic resin having a high molecular weight by esterification,
For example, it can be obtained by subjecting a dicarboxylic acid or tricarboxylic acid and a glycol to a polycondensation reaction. Examples of components used for such polycondensation include terephthalic acid, isophthalic acid, adipic acid, trimellitic acid, fumaric acid, sebacic acid, and other acid components and ethylene glycol, neopentyl glycol, butanediol,
Examples include glycol components such as propylene glycol and ethylene glycol-modified bisphenol A. Also,
Examples of the component that is graft-copolymerized with the copolyester include acrylic acid, acrylic acid esters, maleic anhydride, and styrene, but are not limited thereto. Further, in any case, these graft copolymer resins may be used alone or in combination with other resins. Furthermore, it is possible to use isocyanate, epoxy, acrylic, melamine, etc. together as a curing agent.

The preferred thickness of the adhesion-modifying layer formed on the polyamide-based laminated film of the present invention in which the easy-slip layer constitutes the outermost layer is 0.01 to 10 μm, more preferably 0.02 to 5 μm. Is. If the thickness is less than 0.01 μm, the effect of modifying the adhesiveness is small, and if the thickness exceeds 10 μm, the thickness becomes excessively large, which causes difficulties in the production process such as coating. By forming an adhesion modifying layer on one surface of the polyamide-based laminated film, the adhesiveness, in particular,
It is effective in modifying the water resistant adhesiveness, which is a weak point of polyamide-based films, and is also effective in suppressing the deterioration of adhesiveness and gas barrier property due to boil treatment or retort treatment.

As a method of forming the adhesion modifying layer, for example,
Any method such as a roll coating method, a reverse coating method, a roll brushing method, a spray coating method, an air knife coating method, a gravure coating method, an impregnation method and a curtain coating method can be adopted. There are an in-line method applied at the time of production and an offline method applied at a step different from the step of producing a polyamide-based laminated film, and which method is suitable can be determined depending on the quality and productivity required for the polyamide-based laminated film.

By forming a gas barrier layer on the polyamide-based laminated film of the present invention, the gas-barrier property of the polyamide-based laminated film is further improved, and it can be used as a packaging material which requires high gas barrier properties. .
Examples of the gas barrier layer include a coating layer such as vinylidene chloride copolymer latex, an aluminum vapor deposition layer and an inorganic oxide vapor deposition layer composed of silicon oxide, aluminum oxide, magnesium oxide, and a mixture thereof. Which method to use is selected from the gas barrier quality of the polyamide-based laminated film required as a material for packaging products.

If necessary, the polyamide-based polymer forming the base layer and the slipping layer of the polyamide-based laminated film of the present invention may contain other thermoplastic resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene-.
A polyester-based polymer such as 2,6-naphthalate or a polyolefin-based polymer such as polyethylene or polypropylene may be contained within a range that does not impair the characteristics.

If necessary, various additives such as antistatic agents, antifogging agents, heat stabilizers, UV absorbers, dyes and pigments may be added to the base layer and / or the slipping layer made of a polyamide polymer. It can be added to one or both layers.

The thickness of the polyamide-based laminated film of the present invention is not particularly limited, but when it is used as a packaging material, it is usually 100 μm or less, and generally 5 to 5.
The thickness of 50 μm is used.

The thickness of the thermoplastic film layer having a melting point lower than the melting point of the polyamide polymer constituting the base layer by 30 ° C. or more is usually 20 to 100 μm.

The polyamide-based laminated film of the present invention can be manufactured by a known manufacturing method. For example, a method in which the polymer forming each layer is melted by using a different extruder and produced by coextrusion from one die, a polymer forming each layer is separately melt-extruded into a film, and then a laminating method is used. Any known method such as a method of laminating and a method of combining these can be adopted.

Further, in the polyamide-based laminated film of the present invention, each layer may be either an unstretched film layer or a stretched film layer, but in order to improve the transparency and processability of the laminated film, it is uniaxial or It is preferably a biaxially stretched film layer. As the stretching method, known methods such as a flat type sequential biaxial stretching method, a flat type simultaneous biaxial stretching method, and a tubular method can be used.

[0036]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples. The film was evaluated by the following measuring methods.

(1) Haze A direct-reading haze meter manufactured by Toyo Seiki Seisakusho Co., Ltd. was used and measured according to JIS-K-7105. Haze (%) = [Td (diffused light transmittance%) / Tt (total light transmittance%)] × 100

(2) Maximum height of surface roughness of film surface (SRmax) Three-dimensional fine shape measuring instrument (ET-30H, manufactured by Kosaka Laboratory Ltd.
K) was used, and the cutoff was 80 μm and the drive speed was 100 μm / s.

(3) Coefficient of static friction The coefficient of static friction between the surfaces of the film easy-sliding layer is JIS-K-
It measured based on 7125 in the environment of 23 degreeC and 50% RH.

(4) Impact strength Using a film impact tester manufactured by Toyo Seiki Seisakusho,
It was measured in an environment of 23 ° C. and 65% RH.

(5) Seal strength After the polyester adhesive was applied to the film produced in the example, a linear low density polyethylene film (L-LDP) was used.
E: L6102 manufactured by Toyobo Co., Ltd .: thickness 40 μm) was dry-laminated and aged for 3 days in an environment of 40 ° C. to obtain a laminated film. For the measurement of the seal strength, the linear low-density polyethylene film surfaces of the laminated film are overlapped with each other, and a heat sealer is applied at 160 ° C
Sealing was performed under the conditions of 0.2 MPa and 2 sec, and the sealing strength was measured.

Example 1 An unstretched sheet having the following constitution was obtained by using a coextrusion T-die equipment of two types and two layers. The total thickness of the unstretched sheet is 1 with the easy-slip layer / base layer.
It was 80 μm, and the thickness ratio of the easy-sliding layer to the total thickness was 7.0%. Composition constituting the base layer: 97.0% by weight of nylon 6,
A polymer composition comprising 3.0% by weight of polymethaxylene adipamide. Composition constituting the easy-slip layer: Nylon 6 96.20% by weight, polymetaxylene adipamide 3.0% by weight, ethylenebisstearic acid amide 0.15% by weight, silicon dioxide (average particle size 1 Polymer composition consisting of 0.65% by weight. The obtained unstretched sheet was placed in the longitudinal direction 3.1.
A biaxially stretched film having a thickness of 15 μm is produced by stretching 5 times and then 3.8 times in the transverse direction, and further, a linear low density polyethylene film (L-LDPE: manufactured by Toyobo Co., Ltd., L6102: thickness). 40 μm) and corona discharge treatment of the base layer on the side to be dry laminated.

The haze of the obtained biaxially stretched film, the maximum height of surface roughness (SRmax) of the film surface, the coefficient of static friction, the impact strength and the seal strength were measured. The results are shown in Table 1.

(Example 2) A biaxially stretched film was obtained in the same manner as in Example 1 except that the following parts were changed in the description of Example 1. Composition constituting the easy-slip layer: Nylon 6 96.10% by weight, polymetaxylene adipamide 3.0% by weight, ethylenebisstearic acid amide 0.15% by weight, silicon dioxide (average particle size 1 Polymer composition consisting of 0.75% by weight. The haze of the obtained biaxially stretched film, the maximum height of surface roughness of the film surface (SRmax), the coefficient of static friction, the impact strength, and the seal strength were measured. The results are shown in Table 1.

(Example 3) A biaxially stretched film was obtained in the same manner as in Example 1 except that the following portions were changed in the description of Example 1. An adhesion modifying layer was laminated on the film surface of the obtained polyamide-based laminated film on the base layer side, and further corona discharge treatment was carried out. The adhesiveness-modifying layer is a graft copolymer resin composed of polyester and an acrylic acid component (manufactured by Toyobo Co., Ltd., Tg-20 ° C, acid value 2000e).
q. / Ton) to a thickness of 0.05 μm. The coating was performed by a method in which the film, which had been stretched in the machine direction, was coated, and then stretched in the cross direction.

The haze of the obtained biaxially stretched film, the maximum height of surface roughness of the film surface (SRmax), the coefficient of static friction, the impact strength and the seal strength were measured. The results are shown in Table 1.

Comparative Example 1 A biaxially stretched film was obtained in the same manner as in Example 1 except that the following portions were changed in the description of Example 1. Composition constituting the easy-slip layer: Nylon 6 96.70% by weight, polymeta-xylene adipamide 3.0% by weight, ethylenebisstearic acid amide 0.15% by weight, silicon dioxide (average particle size 1 .9 μm) 0.15% by weight of a polymer composition. The haze of the obtained biaxially stretched film, the maximum height of surface roughness of the film surface (SRmax), the coefficient of static friction, the impact strength, and the seal strength were measured. The results are shown in Table 1.

Comparative Example 2 A biaxially stretched film was obtained in the same manner as in Example 1 except that the following part was changed in the description of Example 1. The following polymer composition was used for both the base layer and the easy slip layer. Composition of base layer and easy-slip layer: Nylon 6 is 96.4
2% by weight, polyamide block copolymer (Daicel
A polymer composition comprising 3.0% by weight of Hyurus, Daiamide), 0.15% by weight of ethylenebisstearic acid amide, and 0.43% by weight of silicon dioxide (average particle size 1.8 μm). The haze of the obtained biaxially stretched film, the maximum height of surface roughness of the film surface (SRmax), the coefficient of static friction, the impact strength, and the seal strength were measured. The results are shown in Table 1.
Shown in.

[0049]

[Table 1]

[0050]

INDUSTRIAL APPLICABILITY The horiamide-based laminated film and the packaging material of the present invention are excellent in slipperiness, transparency and impact resistance, and have good processability in processes such as printing and laminating when used as various packaging materials. In addition, it is also a film suitable for various packaging applications such as foods and pharmaceuticals, because it is excellent in sealing suitability and hermeticity of a laminated film bag product.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Konobu Miyazaki             344 Maebata, East Inuyama, Inuyama City, Aichi Prefecture             Inuyama Factory, Yobo Co., Ltd. F-term (reference) 3E086 AB01 AC07 BA04 BA15 BB21                       BB51 BB55 BB62 BB85 CA01                       CA28                 4F100 AH03B AK01B AK46A AK46B                       AK48 AK63 AR00B AR00C                       AR00D BA02 BA03 BA04                       BA07 BA10A BA10B CA17B                       EJ55 GB16 GB23 JA04 JD02D                       JK10 JK15B JK16 JK16B                       JL11C JN01 YY00 YY00A                       YY00B                 4J002 CL001 CL011 CL031 CL051                       EP016 EP026 FD01 GB01                       GG02

Claims (6)

[Claims] 1. The maximum height (S) of the surface roughness of the film surface constituting the outermost layer on the base layer made of a polyamide polymer.
Rmax) is 1.30 μm or more and is a laminated film formed by laminating easy-sliding layers, and the static friction coefficient between the surfaces of the laminated film on the easy-sliding layer side is 23 ° C. and 50% RH. A polyamide-based laminated film, which is 45 or less. 2. The polyamide-based polymer forming the base layer and / or the easy-slip layer contains 0.01 to 0.40% by weight of a fatty acid amide and / or a fatty acid bisamide. The polyamide-based laminated film described. 3. The polyamide-based laminated film according to claim 1 or 2, wherein a thermoplastic film layer having a melting point lower than the melting point of the polyamide-based polymer constituting the base layer by 30 ° C. or more is formed. 4. The polyamide-based laminated film according to claim 1, wherein an adhesion-modified layer is formed. 5. The polyamide-based laminated film according to claim 1, wherein a gas barrier layer is formed. 6. A packaging material comprising the polyamide-based laminated film according to claim 1, 2, 3, 4 or 5.