JPH06320663A - Linear cut packaging material with metal layer - Google Patents

Abstract

(57) [Summary] [Purpose] In addition to having high strength, heat resistance, gas barrier properties, light blocking properties and heat sealing properties, it also has moisture resistance and aroma retention, and can be easily cut linearly by hand. You can
We will develop a linear cut packaging material that can be used for retort food packaging, pharmaceutical packaging, etc., and can be manufactured continuously at low cost. [Structure] An orientation ratio of the vertical axis (MD) direction and the horizontal axis (TD) direction of 5 or more measured by an infrared dichroic method obtained by uniaxially rolling a film containing a crystalline thermoplastic resin as a main component. The object can be achieved by a linear cut packaging material having a metal layer, which is characterized by being composed of a film or a multilayer film layer including the film and a laminate including a metal layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear cut packaging material having a metal layer, and more particularly, it is used for packaging retort foods such as curry and milk, packaging of pharmaceuticals, etc., and has heat resistance, gas barrier property and light shielding property. The present invention also relates to a linearly-cutting packaging material having a heat-sealing property, a moisture-proofing property, an aroma-retaining property, and the like, and having a metal layer that can be easily cut linearly by hand.

[0002]

2. Description of the Related Art Conventionally, a laminated film composed of a thermoplastic resin film layer and a metal film or a metal foil layer has been used in retort food packaging, pharmaceutical packaging, etc., but it has sufficient linear cutability. However, it has a drawback that the cut line runs diagonally. Such a packaging material has a drawback in that, if an excessive force is applied to the film when it is cut, a problem such as the content popping out from the cut in an unexpected direction occurs. In addition, in general packaging bags, retort packaging bags, pharmaceutical packaging, etc., there are cuts (opening No. 57-80462) and notches (opening No. 58-169044) for opening in parallel with the heat-sealing line. Kaisho 58
No. 156656) is adopted, but the linear cutting property is also poor.

[0003]

In view of the above points, the present invention has sufficient strength to be used for retort food packaging, pharmaceutical packaging, etc., and has heat resistance, gas barrier property, light blocking property, and heat resistance. (EN) Provided is a linear-cut packaging material having a metal layer which has a sealing property, a moisture-proof property, an aroma-retaining property and the like, and which can be easily cut linearly by hand.

[0004]

A first invention of the present invention is to provide a vertical axis (M) measured by an infrared dichroism method obtained by uniaxially rolling a film containing a crystalline thermoplastic resin as a main component.
A linear cut packaging having a metal layer, characterized by comprising a film having a degree of orientation ratio in the D) direction and a transverse axis (TD) direction of 5 or more, or a multilayer film layer including the film and a laminate including a metal layer. It is a material.

A second aspect of the present invention is the linear cut property (X).
Is in the range of 0.8 ≦ X ≦ 1.2, which is a linear cut packaging material having a metal layer according to claim 1.

The present invention will be described in detail below. The crystalline thermoplastic resin (hereinafter abbreviated as TP) of the present invention has high
Polyolefins such as medium / low density polyethylene, polypropylene, polybutene-1, poly-4-methyl-pentene-1, polyhexene-1 and the like, or homopolymers of α / olefins or their intercopolymers, block copolymers, graft copolymers, etc. Examples thereof include resins, polyamide resins, polyester resins, polyvinylidene chloride resins, saponified ethylene-vinyl acetate copolymers, polyvinyl chloride resins, polyvinyl alcohol resins, polyacetal resins, and the like. The melt flow rate (referred to as MFR) of the above TP is 0.01 to 20 g / 10 min., Preferably 0.1 to 10 g / 10 min., And more preferably 0.
It is desirable to select from the range of 5 to 7 g / 10 min. M
If FR is less than 0.01g / 10min.
At 0 g / 10 min. Or more, the strength becomes insufficient.

The material of the metal layer of the present invention includes aluminum, aluminum alloys, iron, iron alloys, tin and its alloys,
These oxides, such as silver and its alloys, nickel and its alloys, mixtures of these metals, mixtures of these metals and metal oxides, etc., can be used as long as they are safe metals, and are not particularly limited. Not something. As the form of the metal layer, one which has been manufactured in advance by a rolling method or the like, for example, specifically a foil, a film, a sheet, or a laminate or coating of a thermoplastic resin on one side or both sides thereof is used. Can be mentioned. Also,
The TP film layer and / or the barrier resin film layer may be preliminarily laminated or coated by a PVD method such as a vacuum deposition method or a sputtering method, or a CVD method utilizing a chemical reaction such as a silver mirror reaction.

The linearly cuttable packaging material having a metal layer of the present invention means a vertical axis (MD) direction and a horizontal axis measured by an infrared dichroic method obtained by uniaxially rolling the film containing TP as a main component. It is characterized by comprising a film having a degree of orientation ratio in the axial (TD) direction of 5 or more, or a multilayer film layer in which the film is laminated with another thermoplastic film, and a laminate containing a metal layer. The stacking order and configuration of the TP film layer and the metal layer of the linear cut packaging material having the metal layer of the present invention are not particularly limited, and can be appropriately selected and determined depending on the purpose of use, application and the like. Particularly, by laminating low-density PE, EVA or the like on both sides of a metal foil or the like, it is possible to prevent pinholes due to bending of the metal foil.

The orientation ratio of the uniaxially rolled film of the present invention is 5 or more, preferably 5 to 15. If the orientation degree ratio is less than 5, the molecular orientation in the MD direction is insufficient and the linear cut property is deteriorated. On the other hand, when the orientation ratio exceeds 15, the molecular orientation in the MD direction is too high, so that the film tends to tear, the mechanical strength becomes unilateral, and the linear cutting property becomes incompatible. In the above-mentioned orientation, at least only the film containing TP as a main component should be oriented.

The linear cutability (X) of the present invention means a width of 50.
10 mm to the left and right from the center of the tape-shaped strip of mm (total 20
mm width) is expressed as a deviation when linearly stretched, and the value is in the range of 0.8 ≦ X ≦ 1.2. More specifically, as shown in FIG. 1, width A (50 mm) and length E
(400 mm) sample film (thickness 20-25 μm)
Insert notches B (50 mm) in the length direction at positions C (15 mm) from both ends of the sample, and insert the notched center part (width D at the start of the test is 20 mm) in the opposite direction to the sample film. (Indicated by an arrow) was pulled and cut at a pulling speed of 1000 mm / min, and the width of the central portion when the cut length reached H (300 mm) was measured (represented by an average value of 5 points of the sample). It is calculated by the formula, and it can be evaluated that the linear cut property is excellent when the value is in the range of 0.8 or more and 1.2 or less. Straight line cutability = width of central part when reaching 300 mm / width at start of test (20 mm)

The thickness of the TP film or the multilayer film containing the TP film varies depending on the purpose, use, etc., but as a general packaging material, it is generally 5 to 250 μm, preferably 7 to 200 μm, more preferably 10 to 150 μm.
The range is appropriate. The thickness of the metal layer also varies depending on the required light blocking property, gas barrier property, etc., but is generally about 300 Å to 250 μm, preferably about 4
A range of from 00 angstroms to 200 μm, more preferably from about 500 angstroms to 150 μm is suitable.

The method for producing a linear cut packaging material having a metal layer according to the present invention includes a TP film obtained by an inflation method, a T-die method or the like, which is uniaxially rolled in advance to form a film oriented by a metal layer or an adhesive. You may laminate | stack the barrier resin which vacuum-deposited the metal layer. As the multilayer film, a coextruded film obtained by an inflation method by coextrusion, a T-die method or the like is a melting point of TP or less 70 ° C., preferably 50 ° C., rolling ratio 2.5 times or more, preferably 3 to 10 times. More preferably, the uniaxial rolling is carried out in the range of 3 to 8 times so that the orientation degree ratio in the vertical axis (MD) direction and the horizontal axis (TD) direction measured by the infrared dichroic method is 5 or more, and the film is obtained. Most preferably, a metal layer is laminated by a dry laminating method, or a metal layer is provided by vacuum vapor deposition. In order to uniformly roll the film, before the uniaxial rolling of the film, the melting point of TP is 50 ° C. or less,
Preheating is preferably carried out in the range of 40 ° C.

The uniaxially oriented film of the present invention is uniaxially oriented by a rolling method. Examples of the rolling method include a constant speed rolling method, a non-constant speed rolling method, and a multistage rolling method. In addition, the rolling method does not cause unevenness of orientation as compared with the stretching method, and it is possible to obtain linear cutability without reducing mechanical strength.

As described above, in the present invention, rolling is TP.
A single layer film may be rolled, and then a multilayer film laminated with another thermoplastic resin may be rolled. For example, TP
Single layer film, TP / acid modified polyethylene (MAnP
E) / saponified ethylene-vinyl acetate copolymer (EVO
H) or other three-layer coextrusion film or three-layer dry laminated film, TP / acid-modified polyethylene (MAnP
E) / saponified ethylene-vinyl acetate copolymer (EVO
H) / acid-modified polyethylene (MAnPE) / TP or other five-layer coextruded film or five-layer dry laminated film may be rolled.

When the sealing material layer is provided in the present invention, a resin having a lower melting point than the TP film, an anchor coating agent, an adhesive agent or the like is used. As the resin having a low melting point, a high pressure radical method low density polyethylene (LDP)
E), linear low-density polyethylene (LLDPE), ultra-low-density polyethylene (VLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene- (meth) ethyl acrylate (EEA) and other ethylene- (meth) Acrylic acid or its ester, propylene-ethylene random copolymer (RPP), acid-modified polyethylene (MAnPE) acid-modified polypropylene (MAnPP) and the like can be mentioned, and they can be appropriately selected and used. The sealing material layer is usually provided by a dry laminating method, an extrusion laminating method, or the like. The thickness of these layers is in the range of 5 to 150 μm, preferably 7 to 100 μm.

Specific examples of the constitution of the packaging material of the present invention include:
HDPE / LDPE / Al layer / LDPE, HDPE / Al layer / LDPE, PP / CP made by dry laminating
P / Al layer / CPP, PP / Al layer / LDPE, PP /
Al layer / CPP, PP / Al layer / LLDPE, ONY /
PP / Al layer / CPP, OPET / PP / Al layer / CP
P, multilayer film by co-extrusion method (PP / MAnPE /
RPP / Al layer / LDPE, RPP / LDPE / made by dry laminating using a uniaxially oriented film (abbreviated as RPP) obtained by uniaxially rolling EVOH / MANnPE / PP)
Al layer / LDPE, RPP / Al layer / CPP, RPP /
CPP / Al layer / CPP, RPP / Al layer / LLDP
E, RPP / LLDPE / Al layer / LLDPE, and the like. (However, Al layer: aluminum layer, HDP
E: high-density polyethylene, LDPE: low-density polyethylene, PP: polypropylene, CPP: polypropylene film, MAnPE: maleic acid-modified polyethylene, E
VOH: Saponified ethylene-vinyl acetate copolymer, ON
Y: biaxially stretched nylon film, OPET: biaxially stretched polyester film. )

The linear cut wrapping material having a metal layer of the present invention is a bag, cup, tube, standing bag,
It is suitably used as a tray or the like for packaging retort foods, pharmaceutical packaging such as PTP packaging, and the like.

In the present invention, other thermoplastic resins, synthetic rubbers, natural rubbers, inorganic or organic fillers, antioxidants, lubricants, pigments, ultraviolet absorbers, etc. are used within the scope not departing from the gist of the present invention depending on the purpose of use. Additives such as a crosslinking agent, a foaming agent and a nucleating agent may be added.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. (Resin used) Polypropylene (PP): [MFR = 1.0 g / 10 mi
n. Density 0.91 g / cm ³ , Nisseki Polypro, manufactured by Nippon Petrochemical Co., Ltd.] Low density polyethylene (LDPE): [MFR = 1.0 g / 1
0 min. Density 0.92 g / cm ³ , Lexron F2
2. Nippon Petrochemical Co., Ltd.] Linear low density polyethylene (LLDPE): [MFR = 2.
0 g / 10 min. Density 0.92 g / cm ³ Linirex AF3710, manufactured by Nippon Petrochemical Co., Ltd.] EVOH: [MFR = 1.3 g / 10 min. EVAL, manufactured by Kuraray Co., Ltd.] EVAL: [Eval film, manufactured by Kuraray Co., Ltd.] Uniaxially oriented polypropylene film (PG): PP Uniaxially oriented multilayer film (RPP): PP / MAnPP /
EVOH / MANnPP / PP Unstretched polypropylene film (CPP): T-die film produced from the above PP Biaxially oriented polyester (OPET): [Emblet,
Unitika Ltd.] Biaxially oriented polyamide (ONY): [emblem, Unitika Ltd.]

(Test Items and Test Methods) (1) Tensile Test (UTS) and Elongation (%) A 10 mm wide strip was cut from a film sample and a tensile speed of 500 mm / min. Was measured at the speed of. (2) Orientation ratio by infrared dichroism method (3) Straight line cutting property 10 mm from the center of a 50 mm wide strip (20 m in total)
The average value when 5 samples were taken as the deviation when the (m width) was pulled. (4) Haze: According to JIS K7105. (5) Gloss: According to JIS Z8741. (6) Water vapor transmission rate: 10 cm × 10 c for a film sample
Make a bag of m (100 cm ² ), enclose approximately 5 g of calcium chloride, seal in four directions, and measure the exact weight (4 digits after the decimal point). Next, a test is conducted for 1 week (168 hours) in an oven of constant temperature and humidity of 40 ° C. and 90% RH. When the test is completed, the weight is accurately measured again, and the water vapor transmission rate is calculated by the following formula. Water vapor transmission rate = [weight after test (g) -weight before test (g)] x K (g / m ² · 24hrs) K: unit conversion coefficient (7) oxygen permeability (cc / m ² · 24hrs · atm) ): JIS K71
According to 26. (8) Gelvo test: According to the test of plastic films and papers specified in US military standard MIL-B131. Measurement conditions: temperature, humidity (23 ± 2 ° C., 50 ± 5% RH) Rotation speed: 40 times / min Twist: 1 rotation 1/4 Film area: 500 cm ² A pinhole formed on the aluminum foil was measured using a polarizing plate. I counted.

(Examples 1 to 4) Using a 50 mmφ extruder, PP was prepared by T die method using PP to prepare raw film having various thicknesses shown in Table 1, and various films shown in Table 1 were produced by rolling method. A uniaxially oriented polypropylene film (PG) (total thickness 25 μm) was produced by rolling at a rolling ratio. Aluminum foil on PG by dry lamination method (hereinafter abbreviated as Al)
(Thickness 7 μm) and LDPE film (thickness 5 μm)
Were laminated to make a packaging material of the present invention. The results of evaluating the packaging material are shown in Table 1. The straight line cutability was good.

(Embodiment 5) The PG made in Embodiment 1 is dry laminated with Al (thickness 7 μm) and CPP.
Films (thickness 40 μm) were laminated to make a packaging material of the present invention. The results of evaluating the packaging material are shown in Table 1. The straight line cutting property was good.

(Embodiment 6) Al (thickness 7 μm) and LLD were formed on the PG prepared in Embodiment 1 by a dry lamination method.
PE films (thickness 40 μm) were laminated to make a packaging material of the present invention. The results of evaluating the packaging material are shown in Table 1.
The straight line cutting property was good.

Example 7 An ONY film (thickness: 15 μm), Al (thickness: 7 μm) and a CPP film (thickness: 40 μm) were laminated on the PG prepared in Example 1 by the dry lamination method with the constitution shown in Table 1. Then, the packaging material of the present invention was prepared. The results of evaluating the packaging material are shown in Table 1. The straight line cutting property was good.

(Embodiment 8) An OPET film (thickness: 15 μm), Al (thickness: 7 μm) and CPP were formed on the PG prepared in the first embodiment by a dry lamination method with the constitution shown in Table 1.
Films (thickness 40 μm) were laminated to make a packaging material of the present invention. The results of evaluating the packaging material are shown in Table 1. The straight line cutting property was good.

(Comparative Example 1) In the same manner as in Example 1, a PP raw film (total thickness 50 μm) was prepared by the T-die method, and rolled by a rolling method at a rolling magnification of 2.0 to obtain a PG film. Made (total thickness 25 μm). Al (thickness 7 μm) and L were formed on this PG film by the dry lamination method.
A DPE film (thickness 5 μm) was laminated to make a packaging material. The results of evaluating the packaging material are shown in Table 1. The linear cut property was 0.6, which was poor.

Comparative Example 2 Biaxially stretched nylon film (ONY, thickness 15 μm), Al (thickness 7 μm), and polypropylene film (CPP, thickness 40 μm) were laminated by the dry lamination method with the constitution shown in Table 1. I made a packaging material. The results of evaluating the packaging material are shown in Table 1. There is no straight line cutting property.

(Comparative Example 3) Biaxially stretched polyester film (OPET, thickness 13 μm), Al (thickness 7 μm),
And polypropylene film (CPP, thickness 40μ
m) was laminated by the dry lamination method with the constitution shown in Table 1 to make a packaging material. The results of evaluating the packaging material are shown in Table 1. There is no straight line cutting property.

(Examples 9 to 12) PP was used as inner and outer layers by a multilayer T-die method using a 50 mmφ extruder, and saponified ethylene-vinyl acetate copolymer (EVOH) was passed through acid-modified polypropylene (MAnPP). Laminated raw films having various thicknesses are prepared and rolled at various rolling ratios shown in Table 2 by a rolling method to produce a uniaxially oriented multilayer film (total thickness 25 μm. PP / MAnPP / EVOH / MAnPP /
(PP thickness composition is 5.5 / 5/4/5 / 5.5 μm)
(RPP) made. An Al foil (thickness 7 μm) and an LDPE film (thickness 5 μm) were laminated on the RPP by a dry lamination method to prepare a packaging material of the present invention. The results of evaluating the packaging material are shown in Table 2. The straight line cutability was good. Gelvo test (2000 times),
After counting the number of pinholes formed on the Al surface, the water vapor permeability and the oxygen permeability were measured, and both showed excellent barrier properties.

(Embodiment 13) Al (thickness 7 μm) and C are formed on the RPP prepared in Embodiment 9 by a dry lamination method.
A wrapping material of the present invention was made by laminating PP films (thickness 40 μm). The results of evaluating the packaging material are shown in Table 2.
The straight line cutting property was good. After the gelbotest in the same manner as in Example 9, the water vapor transmission rate and the oxygen transmission rate were measured and as a result, excellent barrier properties were shown.

(Embodiment 14) Al (thickness 7 μm) and L are formed on the RPP prepared in Embodiment 1 by a dry lamination method.
LDPE films (thickness 40 μm) were laminated to make a packaging material of the present invention. The results of evaluating the packaging material are shown in Table 2. The straight line cutting property was good. After the gelbotest in the same manner as in Example 9, the water vapor transmission rate and the oxygen transmission rate were measured and as a result, excellent barrier properties were shown.

(Comparative Example 4) In the same manner as in Example 9, a multilayer original film (total thickness 50 μm) was prepared by the T-die method, and rolled by a rolling method at a rolling magnification of 2.0 to prepare an RPP film. (Total thickness 25 μm). Al (thickness 7 μm) and LDPE film (thickness 5 μm) were laminated on this RPP film by a dry lamination method to prepare a packaging material. The results of evaluating the packaging material are shown in Table 2. When the water vapor permeability and the oxygen permeability were measured after the gelvo test in the same manner as in Example 9, excellent barrier properties were exhibited, but the linear cut property was poor at 0.7.

Comparative Example 5 In the same manner as in Comparative Example 2, biaxially stretched nylon film (ONY, thickness 15 μm), Al
(Thickness 7 μm), and polypropylene film (CP
P and thickness 40 μm) were laminated by the dry lamination method with the constitution shown in Table 2 to make a packaging material. The results of evaluating the packaging material are shown in Table 2. There was no linear cut property, and when the water vapor permeability and the oxygen permeability were measured after the gelbotest in the same manner as in Example 9, the barrier property was poor.

Comparative Example 6 In the same manner as in Comparative Example 3, a biaxially stretched polyester film (OPET, thickness 13 μm)
m), Al (thickness 7 μm), and polypropylene film (CPP, thickness 40 μm) were laminated by the dry lamination method with the constitution shown in Table 2 to make a packaging material. The results of evaluating the packaging material are shown in Table 2. There was no linear cut property, and when the water vapor permeability and the oxygen permeability were measured after the gelbotest in the same manner as in Example 9, the barrier property was poor.

(Comparative Example 7) Biaxially stretched polyester film (OPET, thickness 13 μm), Al (thickness 7 μm),
An EVAL film (thickness 11 μm) and a polypropylene film (CPP, thickness 40 μm) were laminated by the dry lamination method with the constitution shown in Table 2 to make a packaging material.
The results of evaluating the packaging material are shown in Table 2. There is no linear cuttability, and after gelvo test in the same manner as in Example 9,
When the water vapor permeability and the oxygen permeability were measured, the barrier property was poor.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

INDUSTRIAL APPLICABILITY The linearly cuttable packaging material having a metal layer of the present invention has a vertical axis (MD) measured by an infrared dichroic method obtained by uniaxially rolling a film containing a crystalline thermoplastic resin as a main component. ) Direction and a horizontal axis (TD) direction degree of orientation ratio of 5 or more, or a multilayer film layer including the film, and a laminate including a metal layer, characterized by high strength, heat resistance, gas It has excellent barrier properties, light blocking properties and heat sealing properties, as well as moisture resistance and aroma retention, and can be easily cut linearly by hand, and is used for retort food packaging, pharmaceutical packaging, etc. Also, in the manufacturing process, it can be continuously manufactured at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a test method of linear cuttability (X).

[Explanation of symbols]

 A width of test film B length of notch 50 mm C length from end of test film D width of central part E length of test film H cut length 300 mm

Claims (2)

[Claims] 1. The orientation degree ratio between the vertical axis (MD) direction and the horizontal axis (TD) direction measured by an infrared dichroic method obtained by uniaxially rolling a film containing a crystalline thermoplastic resin as a main component. A linear cut packaging material having a metal layer, comprising a film having 5 or more or a multilayer film layer including the film and a laminate including a metal layer. 2. The linear cut property (X) is 0.8 ≦ X ≦.
The linear cut packaging material having a metal layer according to claim 1, wherein the packaging material is in the range of 1.2.