JP2920969B2 - Polyamide resin laminated film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel polyamide resin laminated film, and more particularly, to a packaging film excellent in heat resistance, adhesiveness, transparency, water vapor barrier property and food safety. About the film.

[Conventional technology and its problems] Conventionally, as an adhesive film used for packaging,
Those using polyvinylidene chloride, polyethylene, polyvinyl chloride or the like as a main raw material are known.

However, a film made of polyvinylidene chloride has a disadvantage that the film shrinks greatly when heated, and a film made of polyethylene melts when it comes into contact with an oily substance (eg, meat or tempura) and becomes hot. In addition, there is a problem that a film made of polyvinyl chloride causes a whitening phenomenon when brought into contact with boiling hot water.

On the other hand, although the aliphatic polyamide resin has excellent heat resistance and mechanical properties, it has high hygroscopicity and cannot maintain its original properties. In particular, copolymerized nylons such as nylon-6, nylon 6 / 6.6, and nylon 6 / 6.10 are characterized in that their monomer component ε-caprolactam bleeds to the film surface.
From the viewpoint of food safety, the use as a packaging film for these applications is restricted.

[Means for Solving the Problems] The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, a polyamide resin composition comprising an aliphatic polyamide resin and a semi-aromatic polyamide resin for an intermediate layer. A laminate film in which the outer layer and the inner layer are made of a polypropylene-based resin composition in which polybutene or polyisobutylene is mixed with a glyceride having an acyl group having 2 to 6 carbon atoms and an acyl group having 8 to 22 carbon atoms in a polypropylene resin. Found that a film having good adhesiveness, transparency, water vapor barrier properties and food safety can be formed while maintaining the excellent heat resistance and mechanical properties inherently possessed by the polyamide resin. Thus, the present invention has been completed.

That is, the gist of the present invention is a laminated film comprising at least an outer layer, an intermediate layer and an inner layer, wherein the outer layer and the inner layer are (A) 100 parts by weight of a polypropylene resin,
(B) 10 to 30 parts by weight of polybutene or polyisobutylene and (C) an acyl group having 2 to 6 carbon atoms and 8 to 22 carbon atoms
Wherein the intermediate layer comprises (D) 100 parts by weight of an aliphatic polyamide resin and (E) 0 to 60 parts by weight of a semi-aromatic polyamide. The present invention resides in a polyamide resin laminated film characterized by being constituted by a polyamide resin composition.

 Hereinafter, the present invention will be described specifically.

(A) of the polypropylene resin composition of the present invention
The polypropylene resin as a component is used as a base material of the composition, and is generally blended in a larger amount than other components (B) and (C). The type of the polypropylene resin that can be used here is not particularly limited, and may be a polypropylene homopolymer or a copolymer of propylene and a small amount of another copolymer component such as ethylene. Examples of the propylene homopolymer include iritactic polypropylene, syndiotactic polypropylene and atactic polypropylene, and isotactic polypropylene is preferable for film formation.

Further, as a copolymer of propylene and another copolymer component such as ethylene, the copolymer component is 20% by weight or less,
Preferably, the content is 10% by weight or less, and either a random copolymer or a block copolymer may be used.

The physical properties of the polypropylene resin as the component (A) may be appropriately selected according to various applications and conditions.
Normally melt flow rate (MFR) 0.5-10g / 10min (JIS
Based on K 6758, measured at 230 ° C and 2.16kg load),
Those having a density of 0.89 to 0.91 g / cm ³ are preferred.

Polybutene or polyisobutylene, which is the component (B) of the polypropylene resin composition of the present invention, acts as a thickener and exhibits excellent tackiness. The amount of the polybutene or polyisobutylene is usually 5 to 40 parts by weight based on 100 parts by weight of the polypropylene resin as the component (A).
Preferably, it is 10 to 30 parts by weight. When the amount is less than 5 parts by weight, sufficient tackiness is not exhibited. On the other hand, when the amount exceeds 40 parts by weight, stickiness due to a large amount of bleeding occurs and heat resistance is lowered, which is not preferable. The physical properties of the polybutene or polyisobutylene used here vary depending on the compounding amount, the type of the other components, the intended use of the composition, and the like, and cannot be generally determined, but usually the number average molecular weight is 550 to 300.
A value of 0, preferably in the range of 1000 to 2500 is preferred.

The glyceride having an acyl group having 2 to 6 carbon atoms and an acyl group having 8 to 22 carbon atoms, which is the component (C) of the polypropylene resin composition of the present invention, is used to form a film molded from the obtained polypropylene resin composition. It exhibits an effect of imparting physical properties such that it can easily be brought into close contact with an object without crimping.

Such a glyceride is required that one of the three hydroxyl groups of glycerin is esterified with a lower fatty acid having 2 to 6 carbon atoms and the other is esterified with a higher fatty acid having 8 to 22 carbon atoms. And a compound such as diacetin or triacetin esterified with a lower fatty acid having 2 to 6 carbon atoms or a higher fatty acid having 8 to 22 carbon atoms. Hereinafter, "hybrid glyceride"). In compounds in which three are esterified, such as triacetin, their acyl groups may, of course, be different. Higher fatty acids have 8 carbon atoms
If it is a fatty acid having up to 22 fatty acids, it may be saturated or unsaturated, and usually a fatty acid having 10 to 18 carbon atoms is preferable. The lower fatty acid may be any one having 2 to 6 carbon atoms.

Specifically, for example, diacetyl monolauryl glycerin, diacetyl monopalmityl glycerin, diacetyl monooleyl glycerin, monoacetyl dilauryl glycerin, monoacetyl monopalmityl glycerin, monoacetyl dioleyl glycerin, monoacetyl monolauryl glycerin, monoacetyl monolauryl glycerin, monoacetyl monoacetyl Oleyl glycerin, cypropionyl monolauryl glycerin, dicaproyl monolauryl glycerin, dicaproyl monopalmityl glycerin, monoacetyl monocapryl glycerin, monoacetyl monobrush glycerin, monopropyl monobrush glycerin, monoacetyl monoerucyl glycerin And the like.

Of course, two or more of these hybrid glycerides may be used in combination.

The amount of the glyceride is usually 0.1 to 10 parts by weight, preferably 1.0 to 5.0 parts by weight, based on 100 parts by weight of the polypropylene resin as the component (A). If the compounding amount is less than 0.1 part by weight, the effect of imparting tackiness is not sufficient, and if it exceeds 10 parts by weight, sticky or remarkable slippage occurs in a film obtained by molding the obtained polypropylene resin composition, Workability will be reduced.

On the other hand, as the aliphatic polyamide which is the component (D) used for the intermediate layer of the laminated film of the present invention, nylon-6, nylon-6.6, nylon-6.10 and nylon-6 / 6.6 copolymer, nylon-6 / 6.6 6.10 Copolymers and the like can be exemplified. However, in order to further clarify the effects of the present invention, those containing ε-caprolactam as a monomer component, i.e., nylon-6, nylon-6 / 6.
It is preferable to use a 6 copolymer, a nylon-6 / 6.10 copolymer or the like.

Further, the semi-aromatic polyamide as the component (E) of the intermediate layer of the laminated film of the present invention has an effect of improving the transparency of the laminated film. The compounding amount of this semi-aromatic polyamide is usually 100 parts of the aliphatic polyamide resin (D).
It is 0 to 60 parts by weight, preferably 0 to 40 parts by weight based on parts by weight. When the transparency of the laminated film does not matter much, it is not necessary to add the component (E). On the other hand, if the amount exceeds 60 parts by weight, transparency is improved, but rigidity is increased, and wrinkles are easily formed in the film, which is not preferable. Various semi-aromatic polyamide resins can be used here. For example, those obtained by polymerization of an aliphatic diamine with isophthalic acid and / or terephthalic acid are preferably used. The semi-aromatic polyamide resin is usually produced by a so-called melt polymerization method by adding a lactam such as caprolactam or lauryl lactam to a nylon salt or an aqueous solution thereof comprising a diamine and a dicarboxylic acid as needed, and isophthalic acid and terephthalic acid. Depending on the composition, it is also produced by a solution method or an interfacial polymerization method. Here, the composition of isophthalic acid and terephthalic acid can take any ratio, but it is usually preferable to use them together in a weight ratio of isophthalic acid: terephthalic acid = 20: 80 to 80:20.

Examples of the aliphatic diamine include those containing a linear aliphatic diamine such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, octamethylenediamine, and decamethylenediamine and derivatives thereof such as methylated, ethylated, and halogenated. .

The polypropylene-based resin composition or the polyamide resin composition of the present invention includes the above-mentioned (A), (B),
It is manufactured by adding the component (C) or the components (D) and (E) and mixing them well. The mixing at this time may be a conventional method, for example, dry blending, or dry blending and then pelletizing with a Banbury mixer, a pelletizer, or the like.

The laminated film of the present invention can be produced using the above resin composition by a lamination method such as a heat bonding method, an extrusion or dry lamination method, and a coextrusion method, and a coextrusion method is particularly preferably used.

Coextrusion is performed by a usual air-cooled inflation method. That is, using a cylindrical round die, the molten polymer is made into a tube shape by, for example, co-extrusion of two types and three layers, and at the same time, air is blown into the inside and gradually expanded to a predetermined width. Alternatively, cool by blowing air, and pick up with the nip roll of the take-off machine.

The thickness of the laminated film is 2 to 50μ, preferably 5 to 30
μ, the thickness of the outer layer and the inner layer is 0.5 to 10 μ each.
And the thickness of the intermediate layer is preferably in the range of 1 to 30 μm.

The layer structure of the laminated film of the present invention essentially comprises an outer layer /
The intermediate layer is formed of at least three resin layers, but may have a structure of four or more layers by further adding a resin layer without departing from the gist of the present invention.
As such a laminated film of four or more layers, for example,
One having an adhesive layer between the outer layer and the intermediate layer, or the inner layer and the intermediate layer, or one having an additional resin layer outside the outer layer or inside the inner layer can be considered.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Predetermined isotactic polypropylene resin as component (A), polybutene and (C) as component (B)
After mixing a predetermined amount of the specified glyceride as a component in a blender, the mixture was mixed using a biaxial pelletizer with a diameter of 30 mm.
Pellets were formed under extrusion conditions of 20 ° C. to produce a polypropylene resin composition.

Using a cylindrical round die two or three layer co-extrusion inflation machine, the above polypropylene resin composition was 40 mm in diameter.
After dry blending a predetermined aliphatic polyamide resin as the component (D) and a predetermined semi-aromatic polyamide resin as the component (E), the extruders are introduced into a 50 mm diameter extruder and molded at 250 ° C. A 10 μm thick film was formed at the temperature. Table 1 shows the conditions and results at this time.

* 1) Ethylene-propylene random copolymer: MFR =
9.0 d = 0.89 (Mitsubishi Kasei Co., Ltd .; Mitsubishi Polypro 6500J) * 2) Polybutene: molecular weight 1450 (Idemitsu Petrochemical Co., Ltd .; polybutene 300H) * 3) Diacetyl monolauryl glycerin (RIKEN Vitamin Oil Co., Ltd.) Riquemar (brand name) PL-
002) * 4) Nylon-6 / 6.6 copolymer (Mitsubishi Chemical Corporation; Novamid) 2030) * 5) Semi-aromatic polyamide (Mitsubishi Chemical Corporation; Novamid) × 21 S04) * 6) Adhesive strength: Lightly overlap two films
0.3mm / cm linear pressure on roll with 25mmφ and 150mm width on film^Two
Pressure three times, and peel off two films within 5 minutes
And the force required for peeling in the 180 ° C direction.
Measure with a Stron type tensile tester.

Measuring method: Shear peel strength test 180 ° peel strength Tensile speed 300mm / min 300mm / min Between chucks 50mm 50mm Sample width 25mm 50mm Adhesive area 25 × 25mm 50 × 50mm * 7) Heat resistance temperature: For a film with a width of 30mm and a length of 150mm The maximum atmosphere temperature at which a tensile load of 10 g was applied and the sample was not broken even when left in an air oven for 1 hour was measured.

* 8) Haze: Measured with a haze meter according to JIS K-6714.

* 9) Moisture permeability: Measured under the conditions of 40 ° C and 90% RH according to JIS Z-0208.

[Effects of the present invention] The laminated film of the present invention uses a specific polypropylene resin composition for the outer layer and the inner layer to provide an adhesive while maintaining the excellent heat resistance and mechanical properties inherently possessed by the polyamide resin. An adhesive film having good properties, transparency, water vapor barrier properties, and food safety can be obtained. Moreover, since this adhesive film does not contain harmful substances,
Particularly, it is suitable for a stretch film for food packaging, a wrap film and the like.

In addition, from the viewpoint of practicality when used as a stretch film or a wrap film, as a value measured in the examples, the adhesive strength is not less than 0.40 kg / cm ² at 180 ° C.
The peel strength is preferably 4.0 g / 50 mm or less, and the transparency is preferably in the range of 2.0% or less in haze.

Continuation of the front page (56) References JP-A-54-36359 (JP, A) JP-A-49-40376 (JP, A) JP-A-1-141737 (JP, A) (58) Fields investigated (Int .Cl. ⁶ , DB name) B32B 1/00-35/00

Claims (1)

(57) [Claims] 1. A laminated film comprising at least three resin layers, an outer layer, an intermediate layer and an inner layer, wherein the outer layer and the inner layer are (A) 100 parts by weight of a polypropylene resin, and (B)
A polypropylene resin composition comprising 10 to 30 parts by weight of polybutene or polyisobutylene and (C) 0.1 to 10 parts by weight of a glyceride having an acyl group having 2 to 6 carbon atoms and an acyl group having 8 to 22 carbon atoms, A polyamide resin laminated film, wherein the intermediate layer comprises a polyamide resin composition comprising (D) 100 parts by weight of an aliphatic polyamide resin and (E) 0 to 60 parts by weight of a semi-aromatic polyamide.