JP4852914B2 - Easy peelable film and double film packaging bag using the same - Google Patents

Description

  The present invention relates to an easily peelable film and a double film packaging bag using the same.

  A packaging form called a back-in box is widely used as a packaging form for semi-solid bodies such as liquids such as beverages, butter, cream, ketchup and the like. The back-in box is a packaging form consisting of an inner bag for preventing leakage of contents, and a cardboard or resin container for preventing the inner bag from being broken due to an impact from the outside. The inner bag for the back-in box is required to have impact resistance, pinhole resistance, etc. to prevent breakage in the distribution process or falling bags. As a back-in-box inner bag having such excellent characteristics, a double film packaging bag is disclosed which is obtained by heat-sealing the outer layers so that the inner layers are in contact with each other (see, for example, Patent Document 1). ).

  The inner bag of the conventional back-in-box is a type in which the inner bag is broken with a scissor or a cutter to take out the contents, or in order to make it easier to take out the contents, A type in which a screw cap is attached to a part of a bag is known. However, the former type has a problem that the safety and workability of the worker are poor, and the latter type has a problem that the manufacturing cost is high, and the screw cap is obstructive and only one inner bag is stored in one outer bag. There was a problem that I could not.

  On the other hand, from the viewpoint of easy removal of the contents, the easy-peelable film as a packaging material that is filled with the contents, cannot be opened in the distribution process, and can be easily peeled off when the contents are opened. It has been known. For example, Patent Document 2 discloses a multilayer film including a surface layer and an inner layer adjacent to the surface layer, wherein the surface layer is a polybutene resin: 2 to 40% by weight and a polyolefin resin other than the polybutene resin. : A layer having a thickness of 2 to 30 μm made of a resin composition containing 98 wt% to 60 wt%, and the inner layer is a layer having a thickness of 2 μm or more made of a polyolefin resin other than the polybutene resin A film is disclosed.

JP 2003-335302 A JP 2000-168003 A

  When producing a normal packaging bag from a film, it is sufficient to seal two films, but when producing a double film packaging bag using a tubular film by the method described in Patent Document 1, A total of three locations, one for the outer layers of the four films and two for the inner layers, are sealed simultaneously. And at the time of opening, it peels in the seal part of the outer layers of a double film packaging bag. However, using an easily peelable film having the composition disclosed in Patent Document 2 formed into a tube shape, and manufacturing a double film packaging bag by the method described in Patent Document 1, while simultaneously sealing three places, It has been difficult to obtain a double film packaging bag that can be sealed so that the sealing portion between the outer layers is not naturally opened in the distribution process and can be easily peeled when opened.

The present invention is a double film packaging bag that can be sealed so that the sealing portion of the outer layers is not naturally opened during the distribution process and can be easily peeled when opened while simultaneously sealing three places. An easily peelable film suitable for the manufacture of a double film packaging bag using the same. Furthermore, this invention provides the bag making filling method which uses a tube-shaped easily peelable film.

That is, the present invention is an easily peelable film having at least a release layer and a support layer, and one surface layer of the easily peelable film is 65 to 94% by weight of a low density ethylene resin, and a linear low density ethylene resin 3 It is a peelable layer composed of ˜25% by weight and a butene-based resin of 3 to 15% by weight, and the other surface layer is an easily peelable film which is a support layer composed of a linear low density ethylene resin.
Furthermore, the present invention provides a double film obtained by pressing the tube-like easily peelable film having an outer surface of a release layer and an inner surface of a support layer so that the support layers are in contact with each other, and making the double film into a bag. It is a heavy film packaging body, It is a double film packaging bag in which the outer surface and inner surface of this double film packaging body are both formed from a peeling layer.
Furthermore, this invention is a bag making filling method using the said tube-shaped easily peelable film, Comprising: It is a bag making filling method which includes the following process (1)-(5) in order.
Step (1): The tube-like easily peelable film according to claim 4 is pressed so that the support layers are in contact with each other to form a double film. Step (2): A pair of sides of the double film facing each other. Step (3) of manufacturing a cylindrical body by sealing the stacked sides substantially in parallel with the overlapped sides: sealing one end of the cylindrical body so as to partially overlap the portion sealed in Step (2) Step (4) to perform: Step (5) for filling the cylindrical body in which the two parts obtained in the step (3) are sealed Step (5): Step for sealing and making the other end of the cylindrical body

  The easily peelable film of the present invention can be sealed so as to have a peel strength that does not naturally unseal the seal part of the outer layers during the distribution process and can be easily peeled when opened, while simultaneously sealing three places. A film suitable for the manufacture of double film packaging. The double film packaging bag of the present invention obtained by using such an easily peelable film has a peel strength at which the seal portion between the outer layers does not open naturally during the distribution process and can be easily peeled when opened. That is, it is a double film packaging bag excellent in easy peelability. Further, according to the bag making and filling method of the present invention, the contents can be filled into a double film packaging bag that can be easily opened at the time of opening without being naturally opened during the distribution process.

The release layer in the easily peelable film of the present invention comprises 65 to 94% by weight of low density ethylene resin, 3 to 25% by weight of linear low density ethylene resin, and 3 to 15% by weight of butene resin. The easily peelable film of the present invention having a release layer having the above composition has a peel strength that does not open naturally during the distribution process and can be easily peeled when opened, that is, has excellent peelability and also has a peelable appearance. It is an excellent film.
The low density ethylene resin of the release layer used in the present invention is generally called LDPE, and the linear low density ethylene resin in the release layer is called LLDPE or an ethylene / α-olefin copolymer. It is. The α-olefin in the ethylene / α-olefin copolymer is an α-olefin having 3 to 12 carbon atoms such as butene-1, hexene-1, octene-1, decene-1, and dodecene-1. Its content is usually 20% by weight or less. Further, the above low density ethylene resin and linear low density ethylene resin have a melt flow rate measured at 190 ° C. under a load of 2.16 kg measured in accordance with JIS K7210 of 15 g / 10 min or less. And from the viewpoint of film processing stability, from the same viewpoint, it is preferable that the density measured in accordance with JIS K7112 is in the range of 910 to 930 kg / m ³ . In addition, unless otherwise indicated, the melt flow rate of the resin in the present invention is a value measured at 190 ° C. and a load of 2.16 kg in accordance with JIS K7210. The density of the resin in the present invention is a value measured according to JIS K7112, unless otherwise specified.

The butene-based resin of the release layer used in the present invention is a butene-1 homopolymer, or butene-1, ethylene and / or so that a structural unit derived from butene-1 in the resin is a main component. Or it is resin obtained by copolymerizing with propylene. The melt flow rate of the butene-based resin used in the present invention is preferably 0.1 to 50 g / 10 min, and more preferably 0.5 to 30 g / 10 min.

The release layer of the present invention may contain a propylene-based resin, a styrene-based resin, an ester-based resin, a petroleum resin, or the like as long as the effects of the present invention are not impaired. Further, a compatibilizer, an antioxidant, a heat stabilizer, an ultraviolet absorber, an antibacterial agent, an antifogging agent and the like may be contained. The thickness of the release layer is preferably 1 to 30 μm, and more preferably 3 to 25 μm.

The linear low density ethylene resin in the support layer of the easily peelable film of the present invention is called LLDPE or ethylene / α-olefin copolymer, as is the linear low density ethylene resin constituting the release layer.

The support layer in the easily peelable film of the present invention includes a low density ethylene resin, a high density ethylene resin, a propylene resin, a styrene resin, an ester resin, a petroleum resin and the like as long as the effects of the present invention are not impaired. It may be. Further, a compatibilizer, an antioxidant, a heat stabilizer, an ultraviolet absorber, an antibacterial agent, an antifogging agent and the like may be contained. Moreover, it is preferable that the thickness of this support layer is 5-200 micrometers, and it is more preferable that it is 10-150 micrometers.

Preferably the density of the linear low density ethylene resin constituting the supporting layer is 895~925kg / m ^3, more preferably 900~920kg / m ^3. If the density of the resin is too small, the inner surface of the tube-like easily peelable film, that is, the support layers are likely to block each other, particularly when used as an inner bag for a back-in box, There are things to do. Moreover, when the density of this resin is too large, the sealing strength of the seal | sticker site | part (support layers) of a double film packaging bag may become weak. Furthermore, the melt flow rate of the linear low density ethylene resin of the support layer is preferably 1 to 15 g / 10 min or less from the viewpoint of inflation process moldability.

As for the easily peelable film of this invention, one surface layer is the said peeling layer, and the other surface layer is the said support layer.
From the standpoint of film rigidity, easily peelable film of the present invention, between the peeling layer and the support layer, density 920~950kg / m ^3, the intermediate layer preferably comprising an ethylene-based resin of density 925~945kg / m ³ It is preferable to have. Examples of the ethylene resin include any one of a low density ethylene resin (LDPE), a linear low density ethylene resin (LLDPE), and a high density polyethylene (HDPE), or a mixture thereof. A linear low density ethylene resin (LLDPE) is preferable from the viewpoint of rigidity and film-forming stability of the easily peelable film.
The thickness of the easily peelable film of the present invention is preferably 30 to 200 μm, more preferably 40 to 150 μm.

An example of the method for producing the easily peelable film of the present invention is an inflation molding method. When producing the easily peelable film of the present invention by inflation molding, it is preferable to mold so that the outer surface is a release layer and the inner surface is a support layer. When it shape | molds so that an inner surface may become a peeling layer, inner surfaces may block.
A tubular film obtained by inflation molding can be cut into an appropriate length to obtain a tube-like easily peelable film. During film formation, the outer layer of the tubular film, that is, the release layer may be subjected to corona treatment.

When using the easily peelable film of this invention as a double film packaging bag, it is preferable to use the tube-like easily peelable film whose outer surface is a release layer and whose inner surface is a support layer. Using the tube-like easily peelable film, the contents can be filled in the double film packaging bag by the method described in JP-A-2003-335302. Specifically, it is a bag making and filling method through the following steps (1) to (5) in order using a tube-like easily peelable film.
Step (1): Pressing the tube-like easily peelable film so that the support layers are in contact with each other to form a double film Step (2): Overlapping a pair of opposite sides of the double film Process step (3) for producing a cylindrical body by sealing substantially parallel to the side: Process step (4) for sealing one end of the cylindrical body so as to partially overlap the part sealed in step (2) : Step of filling the cylindrical body sealed at two places obtained in the step (3) Step (5): Step of sealing the other end of the cylindrical body and making a bag In the filling method, the pillow packaging machine Can be used. The content to be filled is not particularly limited, and examples thereof include liquids such as beverages, butter, margarine, cream, ketchup and the like.

By the method described above, a double film packaging bag filled with the contents is obtained. The double film packaging bag is a double film packaging bag in which the outer surface and the inner surface are both formed from a release layer.
The seal part configuration of the double film packaging bag is as follows: <release layer / support layer> / <support layer / release layer> / <release layer / support layer> / <support layer / release layer> (The symbol // indicates the seal location). When the sealing temperature between the support layers of the film is higher than the sealing temperature between the release layers, the seal strength between the support layers of the double film packaging bag becomes weaker than the seal strength between the release layers, and the double film packaging bag This is not preferable because it cannot be formed.
The sealing temperature in the present invention is that when four heat-peelable films are heat-sealed so that the sealing part has the layer configuration, the sealing strength between the support layers is higher than the sealing strength between the peeling layers, And it is the temperature which can be sealed so that the seal part of peeling layers may show easy peelability.
In the double film packaging bag of the present invention, the outer surface is a release layer composed of 65 to 94% by weight of low density ethylene resin, 3 to 25% by weight of linear low density ethylene resin, and 3 to 15% by weight of butene resin. Such a double film packaging bag of the present invention can be suitably used as an inner bag for a back-in box because the outer surface is excellent in scratch resistance. The scratch resistance is resistance to rubbing against an outer container made of cardboard or resin when used as an inner bag for a back-in box.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples at all.

[Example 1]
A linear low density ethylene resin (trade name Sumikasen E: FV401, melt flow rate = 4 g / 10 min, density = 905 kg / m ³ ) manufactured by Sumitomo Chemical Co., Ltd. was used for the support layer. For the release layer, low-density ethylene resin (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumikasen: F200, melt flow rate = 2 g / 10 min, density = 924 kg / m ³ ) 83% by weight, linear low-density ethylene resin ( Sumitomo Chemical Co., Ltd. trade name Sumikasen E: FV202, melt flow rate = 2 g / 10 min, density = 925 kg / m ³ ) 12% by weight, butene resin (Mitsui Chemicals Co., Ltd., trade name TAFMER: BL3450, Melt flow rate = 4 g / 10 min, density = 900 kg / m ³ ) 5% by weight was used. In the intermediate layer, linear low density ethylene resin (trade name Sumikasen α: FZ203-0, manufactured by Sumitomo Chemical Co., Ltd., melt flow rate = 2 g / 10 min, density = 932 kg / m ³ ) 80% by weight, low density ethylene Resin (trade name Sumikasen manufactured by Sumitomo Chemical Co., Ltd .: F208-1, melt flow rate = 1.5 g / 10 min, density = 923 kg / m ³ ) 20% by weight was used.
Using the above materials, 3 types, 3 layers co-extrusion inflation machine (Extruder A: 50 mmφ, Extruder B: 50 mmφ, Extruder C: 50 mmφ, Layer structure: Tubular film = outer surface / intermediate surface / inner surface = extrusion Using Extruder A / Extruder B / Extruder C), the release layer resin is introduced into Extruder A, the intermediate layer resin is introduced into Extruder B, and the support layer resin is introduced into Extruder C, and molding is performed at an extrusion temperature of 170 ° C. And the laminated | multilayer film laminated | stacked in order of a peeling layer, an intermediate | middle layer, and a support layer were manufactured. The obtained laminated film had a support layer thickness of 25 μm, an intermediate layer thickness of 35 μm, a release layer thickness of 10 μm, and an overall thickness of 70 μm.

[Example 2]
As a release layer resin, a low-density ethylene resin (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumikasen: F200, melt flow rate = 2 g / 10 min, density = 924 kg / m ³ ) 70% by weight, linear low-density ethylene resin ( Sumitomo Chemical Co., Ltd. Trade Name Sumikasen E: FV202, Melt Flow Rate = 2 g / 10 min, Density = 925 kg / m ³ ) 20 wt%, Butene Resin (Mitsui Chemicals Co., Ltd., trade name TAFMER: BL3450, A three-layer / three-layer laminated film was obtained in the same manner as in Example 1 except that 10% by weight of melt flow rate = 4 g / 10 min, density = 900 kg / m ³ ) was used.

[Comparative Example 1]
As a release layer resin, low-density ethylene resin (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumikasen: F200, melt flow rate = 2 g / 10 min, density = 924 kg / m ³ ) 50% by weight, linear low-density ethylene resin ( Sumitomo Chemical Co., Ltd. trade name Sumikasen E: FV202, melt flow rate = 2 g / 10 min, density = 925 kg / m ³ ) 40% by weight, butene resin (Mitsui Chemicals, trade name TAFMER: BL3450, A three-layer / three-layer laminated film was obtained in the same manner as in Example 1 except that 10% by weight of melt flow rate = 4 g / 10 min, density = 900 kg / m ³ ) was used.

[Comparative Example 2]
As the release layer resin, low-density ethylene resin (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumikasen: F200, melt flow rate = 2 g / 10 min, density = 924 kg / m ³ ) 90% by weight, butene resin (Mitsui Chemicals ( Co., Ltd., trade name: TAFMER: BL3450, melt flow rate = 4 g / 10 min, density = 900 kg / m ³ ) Obtained.

[Comparative Example 3]
As a release layer resin, linear low density ethylene resin (trade name Sumikasen E: FV202 manufactured by Sumitomo Chemical Co., Ltd., melt flow rate = 2 g / 10 min, density = 925 kg / m ³ ) 90% by weight, butene resin (Mitsui) Lamination of three types and three layers in the same manner as in Example 1 except that 10% by weight manufactured by Chemical Co., Ltd., trade name TAFMER: BL3450, melt flow rate = 4 g / 10 min, density = 900 kg / m ³ ) was used. A film was obtained.

The films obtained in Examples 1 and 2 and Comparative Examples 1, 2, and 3 were evaluated by the following methods. The results are shown in Table 1.
(1) Easy peelability Corona treatment was applied to the support layer surface of the laminated film obtained in the above examples and comparative examples using a corona treatment machine manufactured by Sakai Kogyo Co., Ltd. Using a coater manufactured by Yasui Seiki Co., Ltd., aliphatic ester coating agent (main agent = Takelac XA-525, Mitsui Takeda Chemical Co., Ltd., curing agent = Takenate XA-52, Mitsui Takeda Chemical Co., Ltd., acetic acid The polyester film (Unitika Ltd., trade name “PTMX”, thickness 25 μm, width 330 mm) coated with ethyl in a weight ratio of 10: 1 to 15 respectively and mixed thoroughly) was applied to the laminated film. After being pressure-bonded to the corona-treated surface, it was heated in an oven at 40 ° C. for 24 hours to obtain an easily peelable film. Two strips of the easily peelable film cut into 70 × 90 mm were used, and the release layers were brought into close contact with each other. A strip having a width of 20 mm at a pressure of 1 kg / cm ² , a time of 1 second, and a seal temperature of 140 ° C. The film was heat sealed in the direction parallel to the 90 mm length of the film. A test piece of 15 mm × 70 mm was cut out at a 15 mm width interval so as to include the seal portion perpendicular to the strip-shaped seal portion. Using a Toyo Seiki Co., Ltd. Autograph AGS500D type tensile tester, the peel strength when peeled 180 ° at a tensile rate of 300 mm / min in an atmosphere at 23 ° C. was measured. A film having a peel strength of 3 to 10 N / 15 mm width was judged to have a peel strength that does not open during the distribution process and can be easily peeled when opened when a double film packaging bag is used.

(2) Peeling appearance The peelable part of the easily peelable film after measuring the peel strength in (1) above was observed, and the resin that could not be peeled due to resin elongation (stringing) or film breakage was evaluated as x (defective appearance). The case where no elongation was recognized and the appearance was excellent was evaluated as ◯.

(3) Measurement of heat fusion temperature A sample of 70 × 90 mm was obtained from each laminated film obtained in the above examples and comparative examples. Four samples (film A, film B, film C, film D) were used, and film A (release layer a / support layer a) / film B (support layer b / release layer b) / film C (release layer c) / Support layer c) / film D (support layer d / release layer d) in the same order as the sealing part of the double film packaging bag, with a pressure of 1 kg / cm ² and a time of 0.5 seconds, Heat sealing was performed in a band shape having a width of 20 mm (in a direction parallel to the length of 90 mm of the laminated film) at a temperature of 5 ° C. from 80 ° C. to 140 ° C. A test piece of 15 mm × 70 mm was produced by cutting out at a 15 mm width interval so as to include the seal portion perpendicular to the strip-shaped seal portion. The fusion part of film A and film B of the test piece was peeled by hand, and the lowest sealing temperature when film elongation or film breakage occurred and could not be peeled was defined as the heat fusion temperature of the support layer.

(4) A test piece was prepared in the same manner as in (3) except that the proper sealing temperature for the double film packaging bag was 140 ° C. and the sealing time was 1 second. The peeling form when the test piece was peeled by hand was evaluated.
○: Between the film A and the film B (support layers) and between the film C and the film D (support layers), and between the film B and the film C (release layers) It can be peeled off and has excellent peeling appearance.
X (1): When peeled between the film B and the film C (peeling layers), the resin elongation is severe and the peeled appearance is poor.
X (2): The support layers are sealed, but the peel strength of the seal portion between the peel layers is low. (There is a risk of opening in the distribution process)
X (3): Peeling strength between film B and film C (peeling layers) is too high, and peeling is difficult.

Claims (7)

An easily peelable film having at least a release layer and a support layer, wherein one surface layer of the easily peelable film is 65 to 94% by weight of low density ethylene resin, 3 to 25% by weight of linear low density ethylene resin, An easily peelable film, which is a release layer composed of 3 to 15% by weight of a butene-based resin, and the other surface layer is a support layer composed of a linear low density ethylene resin. The linear low density ethylene resin constituting the support layer has a density of 895 to 925 kg / m ³ and a melt flow rate measured at 190 ° C. and a load of 2.16 kg is 1 to 15 g / 10 minutes. Item 10. The easily peelable film according to Item 1. The easily peelable film of Claim 1 or 2 which has an intermediate | middle layer which consists of an ethylene-type resin with a density of 920-950 kg / m < ³ > between a peeling layer and a support layer. The easily peelable film according to any one of claims 1 to 3, wherein the outer surface is a tube-shaped easily peelable film having a release layer and the inner surface is a support layer. A double film package obtained by pressing the tubular easily peelable film according to claim 4 so that the support layers are in contact with each other to form a double film, and bag-making the double film, A double film packaging bag in which an outer surface and an inner surface of a film package are both formed from a release layer. The double film packaging bag according to claim 5, which is an inner bag for a back-in box. It is a bag making filling method using the tube-shaped easily peelable film of Claim 4, Comprising: The bag making filling method which contains the following process (1)-(5) in order.
Step (1): The tube-like easily peelable film according to claim 4 is pressed so that the support layers are in contact with each other to form a double film. Step (2): A pair of sides of the double film facing each other. Step (3) of manufacturing a cylindrical body by sealing the stacked sides substantially in parallel with the overlapped sides: sealing one end of the cylindrical body so as to partially overlap the portion sealed in Step (2) Step (4) to perform: Step (5) for filling the contents into the cylindrical body sealed at the two places obtained in the step (3) (5): Step for sealing and making the other end of the cylindrical body