JP3199499U - Self-supporting easy-open bag - Google Patents

Abstract

An easily openable bag using an inflation film that can be easily self-supported when the contents are enclosed and can be easily opened by hand or the like. Forming a gusset that has a shape that extends obliquely from a side edge to a bottom edge at each of the lower left and right ends of a bag using a cylindrically formed inflation film as a film forming a bag 1 A linear heat seal part 2 is provided, and a notch 3 for opening is provided on the side edge or bottom edge of the side edge below the start position of the heat seal part. Features. [Selection] Figure 1

Description

  The present invention relates to a bag using an inflation film that can be easily self-supported when the contents are enclosed and can be easily opened by hand or the like.

Conventionally, as a method of forming a bag by using a film to fill the contents, a method of heat-sealing the lower end portion of an inflation film extruded into a cylindrical shape to form a bag, one sheet Folding the film, heat sealing one side edge and bottom edge (three-side sealed bag), heating the back center instead of the side edge (pillow bag) There is a method of stacking two films and heat-sealing both side edges and bottom edge to make a bag (four-side sealed bag), both of which are used after sealing the top edge It becomes.
Although a bag is formed mainly using a thermoplastic resin film that can be heat-sealed, such as a polyethylene resin film, it is difficult to achieve both the content protection performance and the easy-open performance.
In particular, there has been a long-standing need to easily open the sealed part by hand without using a bag or the like, but ordinary thermoplastic resin films such as polyethylene are sticky and easily tear by hand. It is not possible.
However, in recent years, the present applicant has proposed a polyethylene-based multilayer film having a special layer structure for imparting easy tearability (straight cut property) to the film itself (Patent Document 1, etc.). With this polyethylene-based multilayer film, even a bag formed using an inflation film can be easily opened linearly in the lateral direction by hand. However, it is preferable to provide a notch-shaped opening start point called a notch at the opening start point.

Such a notch is often provided in a belt-like heat-sealed portion provided at the side edge or belt of a three-side sealed bag, pillow-type bag, or four-side sealed bag, Since there is no heat seal part at the side end in the bag formed of the inflation film, for example, as described in Patent Document 2, a notch is provided at the side end without the heat seal of the bag using the inflation film, An easy-open bag having a heat seal around the arc has also been proposed.
However, there is a demand for a method of adding a notch to a bag using an inflation film by a simple method in the manufacturing process and in addition to other functions.

JP 2012-000885 A Japanese Unexamined Patent Publication No. 7-329991

  Accordingly, an object of the present invention is to provide a bag that can be easily self-supported when the contents are sealed and can be easily opened by hand at an arbitrary position in a simple manner in the manufacturing process.

As a result of studying to solve such a problem, the present inventor has obliquely formed a linear heat seal portion for forming a triangular so-called gusset on each of the left and right lower ends of a bag formed of an inflation film. With providing the notch for opening at the heat-sealed part and the part surrounded by the lower end of the film, by a simple manufacturing process, both the self-sustainability of the bag and easy easy opening, The present inventors have found that a packaging bag that can be easily applied to a bag making process that is continuously performed at high speed can be obtained.
That is, according to the first aspect of the present invention, as a film for forming a bag, a bag using a blown film formed into a cylindrical shape is obliquely formed from the side edge to the bottom edge at the lower left and right ends, respectively. A linear heat-sealed portion having a shape that reaches the upper end, and a notch for opening is provided at the side edge of the side edge below the start position of the heat-sealed portion. Openable bag.
The second device is a line having a shape that extends obliquely from the side edge to the bottom edge at the lower left and right ends of the bag using a tubular-shaped inflation film as a film forming the bag. An easily openable bag characterized in that a notch for opening is provided at the bottom edge of the bottom end edge from the start position of the heat seal part. .
A third device is the easily openable bag according to the first or second invention, wherein the film forming the bag is an inflation film having an Elmendorf tear strength in the film TD direction of 50 N / mm or less. is there.
In a fourth aspect of the present invention, the film forming the bag is an inflation film having an Elmendorf tear strength in the film MD direction of 50 N / mm or less. Openable bag.
A fifth invention is characterized in that the film forming the bag is a multilayer film having a mixed resin layer of a cyclic polyolefin resin and a polyethylene resin at least in an intermediate layer thereof. The easy-open bag according to any one of the above.
A sixth invention is characterized in that the multilayer film is a multilayer film having an outer layer made of a polyolefin resin and an inner layer made of a polyolefin resin on both surfaces of the intermediate layer, It is an easily openable bag.
According to a seventh invention, the multilayer film has an outer layer (A) mainly composed of polyethylene (a) having a density of 0.870 to 0.960 g / cm ³ and a cyclic olefin resin (b1) of 10 to 90 weights. % and an intermediate layer density polyethylene 90 to 10 wt% of 0.870~0.960g / cm ³ and the resin main component (B), and polyethylene having a density of 0.870~0.960g / cm ³ ( The easy-open bag according to the fifth or sixth invention, characterized in that it is a multilayer film containing an inner layer (C) whose main component is c).
An eighth device is the easy-open bag according to any one of the first to seventh inventions, wherein the opening notch is a cross-shaped notch.

  According to such a configuration, an easy-open bag formed of an inflation film that has both self-supporting properties and easy-open properties can be obtained without adding extra steps in the manufacturing process.

It is a figure which shows an example of the easily openable bag using the inflation film of this invention. It is a figure which shows another example of the easily openable bag using the inflation film of this invention. It is a figure which shows another example of the easily openable bag using the inflation film of this invention.

  1 ·· Packing bag, 1a ·· Right edge, 1b ·· Left edge, 1c ·· Bottom edge, 1d ·· Upper edge, 1e ·· Right lower edge, 1f ·· Left lower edge, 2 ·· Linear Heat seal part, 3 ... opening notch, 3 '... cross notch opening notch, 4 ... bottom edge heat seal part

Hereinafter, the easily openable bag of this invention is demonstrated in detail based on drawing.
1. Bag shape and gusset forming heat seal part FIG. 1 shows an example of an embodiment of the present invention, and FIGS. 2 and 3 show examples of another embodiment of the present invention.
As shown in FIGS. 1 to 3, the embodiment of the present invention is a bag 1 formed of an inflation film formed into a cylindrical shape, specifically, a right side edge 1a and a left side formed by folding. It has an end edge 1b, a bottom end edge 1c whose open end is bonded by a linear bottom end edge heat seal portion 4, and an upper end edge 1d.
Further, according to the present invention, the linear heat is formed so that each of the left and right end portions (1e .. lower right end, 1 f .. lower left end) of the lower side of the bag obliquely extends from the side edge to the bottom edge. A seal part 2 (hereinafter also referred to as “gusset-forming heat seal part 2”) is provided.
By providing such diagonal linear heat seal portions 2 at the left and right end portions, so-called triangular gussets can be formed at both the left and right ends. By using this, the packaging bag can be easily made independent.
The position and size of the oblique linear heat seal portion can be arbitrarily set within a range that can stand by itself depending on the size of the bag to be formed, but in a substantially isosceles triangle shape with respect to both ends. A linear heat seal portion having a position and a size as described above is preferable.
Specifically, the length from the end of the bag to the contact point between the bottom edge and the slanted linear heat seal portion is in the range of 1/3 to 1/10 of the lateral length of the bag. It is preferable that Also, the length (p) from the end of the bag to the contact point of the inclined heat seal part at the side edge, and the length (r) from the end of the bag to the contact point of the inclined heat seal part at the bottom edge The ratio of (p / r) is preferably in the range of 1/3 to 3/1.

2. Opening Notch There are two positions in the present invention for providing the notch of the present invention.
One aspect is as follows: 1) As shown in FIG. 1, a notch for opening is provided on the side edge of the side edge of the bag below the start position of the heat seal portion. 2) As shown in FIG. 2, the opening is provided with a notch for opening at the bottom end edge of the bottom end edge of the bag from the start position of the heat seal portion.
In the bag of the present invention, the opening direction of the bag is the direction parallel to the bottom edge (see the dotted arrow in the figure) as shown in FIG. On the other hand, in the case of 2), as shown in FIG. 2, the direction is parallel to the side edge (see the dotted arrow in the figure).
Further, a plurality of opening notches may be provided on the same edge. In that case, since the size of the opening varies depending on the position of the notch, the size of the opening can be arbitrarily selected. Alternatively, opening notches may be provided on both the side edge and the bottom edge.
As the shape of the notch, a known notch shape such as an I-shaped notch or a V-shaped notch can be used, and as shown in FIG. Can also be used. In this case, after opening in the horizontal direction, the bag can be opened in the vertical direction as necessary, and the contents can be taken out more easily.

3. Film The bag 1 of the present invention is characterized in that, as a first feature thereof, a tubular film is used as the film material.
As a particularly preferable film material, it is possible to use a multilayer film having a mixed resin layer of a cyclic polyolefin resin and a polyethylene resin in at least the intermediate layer.
Even if the film is an inflation film, it is excellent in linear tearing property in the transverse direction (TD) especially during film production, and also has an easy tearing property that has important impact strength as a packaging bag. It is a film.
The thermoplastic resin film that is easily tearable in the transverse direction is specifically the width direction perpendicular to the film flow direction (MD), which is the direction in which the film is drawn during film production, that is, the transverse direction of the film (TD). The Elmendorf tear strength (Elmendorf tear strength measured according to JIS K7128-2) is 50 N / mm or less, preferably 10 N / mm or less, 7 N / mm or less. In particular, the Elmendorf tear strength in the width direction (lateral direction) when forming an inflation film is 50 N / mm or less.
In addition, when a film having a longitudinal direction Elmendorf tear strength of 50 N / mm or less is used, tearing in the longitudinal direction is possible.
Moreover, it is preferable that the impact strength measured based on JISK7124-1 is 100 g / 30 micrometers or more. More preferably, it is 130 g / 30 μm or more. The impact strength according to JIS K7124-1 is also called drop drop impact strength or punching strength (DDI), and is measured by dropping a specific weight on the film.

(1) Layer structure When a particularly preferable resin / layer structure is exemplified, the multilayer film is a multilayer film of three or more layers having an outer layer made of a polyolefin resin and an inner layer made of a polyolefin resin on both surfaces of the intermediate layer. Preferably there is.
More preferably, the outer layer (A) mainly comprises polyethylene (a) having a density of 0.870 to 0.960 g / cm ³ , and 10 to 90% by weight of the cyclic olefin resin (b1). 870~0.960g / cm ³ polyethylene (b2) an intermediate layer of 10 to 90 wt% and the resin main component (B), and a density of 0.870~0.960g / cm ³ polyethylene (c) A multilayer film of three or more layers having at least an inner layer (C) containing a resin as a main component can be mentioned.
Particularly preferably, the outer layer (A) mainly comprises polyethylene (a) having a density of 0.870 to 0.935 g / cm ³ , and 10 to 90% by weight of the cyclic olefin resin (b1). polyethylene 870~0.935g / cm ³ (b2) an intermediate layer of 10 to 90 wt% and the resin main component (B) and density 0.870~0.935g / cm ³ of polyethylene (c) a resin main A multilayer film of three or more layers having at least the inner layer (C) as a component is preferred.

(A) Cyclic olefin resin (b1)
Examples of the cyclic olefin resin (b1) used in the intermediate layer (B) of the easily tearable film include a norbornene polymer, a vinyl alicyclic hydrocarbon polymer, and a cyclic conjugated diene polymer. Among these, norbornene-based polymers are preferable. The norbornene polymer includes a ring-opening polymer of a norbornene monomer (hereinafter also referred to as “COP”), a norbornene copolymer obtained by copolymerizing a norbornene monomer and an α-olefin such as ethylene. And the like (hereinafter also referred to as “COC”). COP and COC hydrogenated products can also be used. In the present invention, the cyclic olefin resin (b1) is preferably COC for the reason of dispersibility in polyethylene. The COC is preferably an ethylene / cyclic olefin copolymer in which the linear monomer is ethylene.

(B) Polyethylene resin (b2)
The polyethylene resin (b2) used for forming the intermediate layer (B) is an ethylene homopolymer or a copolymer of ethylene and α-olefin, which is a metallocene catalyst, Ziegler catalyst, or Phillips catalyst. Any of those polymerized by, for example, may be used. The density is preferably a low density polyethylene in the range of 0.870 to 0.960 g / cm ³ , particularly 0.870 to 0.935 g / cm ³ , more preferably 0.910 to 0.933 g / cm 3. ³ . In particular, linear low density polyethylene (LLDPE) is preferable. When the density is less than 0.870 g / cm ³ , sufficient rigidity cannot be obtained, and the high-speed packaging machine may be inferior in suitability. On the other hand, if the density is too high, sufficient transparency may not be obtained.
In the present invention, the density is a value measured based on JIS K 6922-2.

(2) Outer layer (A) or inner layer (C)
The outer layer (A) or the inner layer (C) in the easily tearable multilayer film of the present invention is an olefin resin, preferably polyethylene having a density of 0.870 to 0.960 g / cm ³ , preferably the density of polyethylene is 0. 910-0.930 g / cm ³ . Any polyethylene in the above density range can be used because it has good strength, rigidity and transparency. Preferred polyethylene includes linear low density polyethylene.
As described above, the easily tearable multilayer film of the present invention is preferably composed of outer layer (A) / specific intermediate layer (B) / inner layer (C). The total thickness of the easily tearable multilayer film is preferably 30 to 150 μm. If the thickness of the multilayer film is 30 μm or more, excellent secondary formability can be obtained. Moreover, in the range whose thickness of a multilayer film is 50-80 micrometers, it can be used as a bag-shaped packaging material which heat-sealed inner layers (C). Furthermore, the easily tearable multilayer film of the present invention is excellent in easy tearing even if the thickness is 100 μm or more.

4). Production of bag using film and heat sealing, notching The bag according to the present invention can be made into a bag by the following method using the multilayer film.
In particular, the bag of the present invention has a great merit in that it can be applied to bags for packing heavy objects such as rice and fertilizers, and inflation molded bags using an inflation film used for an inner bag used in a paper bag. Have.
The cylindrical film obtained by inflation molding is formed at the same time or under separate processes for the bottom edge heat seal part and the gusset forming heat seal part of the present invention in the process of being continuously conveyed. Is cut (6) to form a bag.
The notch imparting step of the present invention can be performed in the same step as the heat sealing step or in separate steps before and after using any conventionally known method.
The bag is used after the contents are put and then the upper end of the bag is heat sealed. At the time of opening, it is opened and used in the lateral direction (arrow direction in the figure) from the lower side end portion of the upper end heat seal portion.

  Examples of the easy-open bag of the present invention include packaging bags, packaging containers and the like used for foods, medicines, medical instruments, industrial parts, miscellaneous goods, magazines, etc. It is suitable for certain large bags, for example, heavy-weight packaging bags such as rice bags and fertilizer bags.

Claims (8)

  As the film forming the bag, a linear heat-sealed portion is formed on each of the lower left and right ends of the bag using the blown film formed into a cylindrical shape, reaching the bottom edge obliquely from the side edge. An easily openable bag characterized in that an opening notch is provided at a side end edge below the start position of the heat seal portion at the side end edge.   As the film forming the bag, a linear heat-sealed portion is formed on each of the lower left and right ends of the bag using the blown film formed into a cylindrical shape, reaching the bottom edge obliquely from the side edge. An easily openable bag, characterized in that an opening notch is provided at the bottom end edge of the bottom end edge closer to the end side than the starting position of the heat seal portion.   The easily openable bag according to claim 1 or 2, wherein the film forming the bag is an inflation film having an Elmendorf tear strength in the film TD direction of 50 N / mm or less.   The easily openable bag according to any one of claims 1 to 3, wherein the film forming the bag is an inflation film having an Elmendorf tear strength in the film MD direction of 50 N / mm or less.   The film forming the bag is a multilayer film having a mixed resin layer of a cyclic polyolefin-based resin and a polyethylene-based resin at least in an intermediate layer thereof. Openable bag.   6. The easily openable bag according to claim 5, wherein the multilayer film is a multilayer film having an outer layer made of a polyolefin resin and an inner layer made of a polyolefin resin on both surfaces of the intermediate layer. The multilayer film has an outer layer (A) mainly composed of polyethylene (a) having a density of 0.870 to 0.960 g / cm ³ and a cyclic olefin resin (b1) of 10 to 90% by weight and a density of 0.8. intermediate layer of polyethylene 90 to 10 wt% and the resin main component of 870~0.960g / cm ³ (B), and a density polyethylene (c) of 0.870~0.960g / cm ³ resin main component The easily openable bag according to claim 5 or 6, wherein the bag is a multilayer film containing the inner layer (C).   The easily openable bag according to any one of claims 1 to 7, wherein the opening notch is a cross-shaped notch.

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