JP3189169U - Easy opening bag, easy tear film and easy tear tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily apply a bag which can be easily opened at an arbitrary position by hand, particularly a bag using an inflation film or a film or tape which can be easily torn, to a bag making process which is continuously performed at a higher speed. Therefore, a bag, a film, or a tape having excellent linear cutability in the lateral direction is provided. SOLUTION: As a film 1 forming a bag, a large number of small pieces are formed on an end portion 3 of a bag made into a bag by using a multilayer film having a mixed resin layer of a cyclic polyolefin resin and a polyethylene resin in at least an intermediate layer thereof. An easy-to-open bag, an easy-to-tear film, and a tape, characterized in that the wounds are densely provided in a band shape. [Selection diagram] Fig. 1

Description

  The present invention relates to a bag that can be easily opened by hand at any position, especially a bag using an inflation film, or an easily tearable film, and a tape. The present invention relates to a bag, a film, or a tape that can be applied to the above and has excellent linear cutability in the lateral direction.

Conventionally, thermoplastic resin films that can be heat-sealed have been frequently used for applications such as pouches, pillow bags, and stick bags, but it is difficult to achieve both the protection performance of the contents 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.
Therefore, various devices have been studied in the past for imparting easy tearability (straight cut property) to the thermoplastic resin film material itself and for imparting notches and sewing lines to facilitate opening. Yes.

Various attempts have been made to give easy tearability to the film material itself, but many of the easy-open films currently on the market can be easily torn in one direction by uniaxially stretching in the horizontal or vertical direction. Mainly used are polypropylene films and ultrahigh density polyethylene films (transverse uniaxially stretched PP, longitudinal uniaxially stretched HDPE, etc.). Such a uniaxially stretched film is easier to stretch in the longitudinal direction of the film flow continuously in the film production process. However, when uniaxially stretched, it is easy to tear in the longitudinal direction, but tears in the lateral direction. It becomes a difficult property.

On the other hand, as a device for facilitating opening, conventionally known methods include a notch (notch) indicating a tear starting point and a method of imparting a sewing line, etc. As the notch shape, a notch I notch, A notch V cut, a sawtooth cut, and the like are known.
Such notches and sewing lines are usually provided on the side of the packaging bag or the heat-sealed part of the belt. However, in the manufacturing process of high-speed packaging bags, the notch or sewing line is placed at the desired position. There was a problem that it was difficult to control.
There is also known a packaging bag using an easy-opening technique and a uniaxially stretched film in which a large number of small scratches are densely provided at the end or band of the bag in a band shape (see Patent Document 1).

In addition, the process of adding such a small wound group in a strip shape is performed simultaneously with the post-process of rotating the roll body having a small blade or the like, sealing the film into a bag shape, or forming the bag. Therefore, it is efficient to apply it in the longitudinal direction of the film (the direction in which the film flows with respect to the machine, also referred to as the MD direction). Therefore, the opening direction of the bag is the transverse direction (also referred to as the TD direction) with respect to the film. However, bags using a film material of longitudinal uniaxial stretching cannot be easily opened because the tearability in the lateral direction is poor. In the case of applying a uniaxially stretched film, there is a disadvantage that the apparatus becomes large in order to continuously supply the laterally uniaxially stretched film, and the cost is increased.

Japanese Examined Patent Publication No. 61-39228

  Therefore, an object of the present invention is to provide a bag that can be easily opened in the lateral direction by hand at any position, particularly a bag using an inflation film or an easily tearable film or tape at any position. Another object of the present invention is to provide a bag or film that can be easily applied to a bag-making process that is continuously performed at a higher speed and that is excellent in the linear cut in the lateral direction.

  As a result of studying to solve such a problem, the present inventor, as means for facilitating opening, a large number of small wound groups in a band shape at the end or band of the bag or a part of the film or tape. In addition to adopting the technology to be provided, the film material is easily tearable in the lateral direction of the film, that is, easily in the lateral direction even in the state of an inflation film that does not perform special secondary stretching such as uniaxial stretching. By adopting and combining films that can be torn, a packaging bag or film that can be easily applied to a bag making process continuously performed at a high speed and can be easily opened in the lateral direction is obtained. I found out and reached the present invention.

  That is, the feature of the present invention is that, as a first device, as a film forming a bag, a side edge of a bag using a multilayer film having a mixed resin layer of a cyclic polyolefin resin and a polyethylene resin as at least an intermediate layer thereof. An easy-open bag characterized in that a large number of small wound groups are provided in a band shape along the section or band.

In addition, the following ideas can be given.
A second device is an easily openable bag according to the first device, characterized in that the bag is a bag using an inflation film formed into a cylindrical shape.
A third device is characterized in that a heat seal portion is provided along a side end portion of a bag using the inflation film, and the multiple small wound groups are provided in the heat seal portion of the side end portion. The easy-open bag described in the second device.
A fourth device is characterized in that the bag is a three-sided seal-type bag, a four-sided seal-type bag, or a pillow-type bag, and the plurality of small wound groups are provided in any one of the heat seal portions. The easy-open bag according to the first device.
The fifth device is an easily openable bag according to any one of the first to fourth devices, characterized in that the large number of small wound groups are provided at side end portions on both sides of the bag.
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. An easily openable bag according to crab.
In a seventh device, 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 any one of the first to sixth devices, which is a multilayer film containing an inner layer (C) whose main component is c).
The eighth invention is the easily openable bag according to any one of the first to seventh aspects, wherein the multilayer film is a film having an EM direction of the Elmendorf tear of 50 N / mm or less.

The ninth device is characterized in that a plurality of small wound groups are provided in a strip shape on a part of a multilayer film having a mixed resin layer of a cyclic polyolefin resin and a polyethylene resin at least in the intermediate layer. the film.
A tenth device is the easily tearable film according to the ninth device, characterized in that the large number of small wound groups are provided at an end of the film.
An eleventh aspect of the present invention is the easily tearable film according to the ninth aspect, characterized in that the large number of small wound groups are provided in a portion other than the end of the film.
In a twelfth aspect of the invention, any one of the ninth to eleventh aspects, 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 easily tearable film of crab.
A thirteenth device is an easily tearable film according to any one of the ninth to twelfth devices, wherein the film is a film for shrink wrapping.
A fourteenth device is an easy tear tape using the easy tear film according to any one of the ninth to thirteenth devices as a film constituting the tape.

According to such a configuration, the bag can be easily opened by hand without any tools such as a bag at any position. Furthermore, it can be easily applied to bag-making processing continuously performed at a high speed, and difficult to achieve with a technology using a normal uniaxially stretched film, at any position of a bag formed of an inflation film, An easily openable bag can be obtained in the lateral direction.
Also, by applying this technique, a film or tape that can be easily torn by hand at an arbitrary position can be obtained.

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

  1 .. Packaging bag, 1 '... Film, tape 2. Lower end heat seal part 3 .... Many small wound groups provided in a band 4. 4. Lateral direction (width direction) 5 .... Longitudinal direction

Hereinafter, the easily openable bag, easily tearable film, and easily tearable tape of the present invention will be described in detail.
1. Easy tear film As a first feature of the bag, film or tape of the present invention, a multilayer film having a mixed resin layer of a cyclic polyolefin resin and a polyethylene resin as at least an intermediate layer thereof is used as the film material. Is mentioned.
The film has excellent linear easy tearability in the transverse direction (TD) at the time of film production, and does not require a special secondary process such as transverse uniaxial stretching. And a multi-layer film having easy tearability.
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, this film has a longitudinal direction Elmendorf tear strength of 50 N / mm or less, and can be torn in the longitudinal direction.
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 constitution A particularly preferred resin / layer constitution is exemplified by 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.

As a commercial product that can be used as the cyclic olefin-based resin (b1), examples of the ring-opening polymer (COP) of the norbornene-based monomer include “ZEONOR (registered trademark)” manufactured by Nippon Zeon Co., Ltd. Examples of the norbornene copolymer (COC) include “Apel (registered trademark)” manufactured by Mitsui Chemicals, Inc. and “TOPAS (registered trademark)” manufactured by Polyplastics.

(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 0.970 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.
As a film forming method, a known manufacturing method such as an inflation forming method for forming a cylindrical film, a T-die forming method for forming a normal single film, or a calendar forming method can be employed.

2. In the present invention, in the present invention, in the case of the end of the bag or in the case of the pillow bag, at the so-called opening portion of the band provided on the back surface, along the edge line as shown in FIG. A large number of small wounds are densely provided in a band shape (hereinafter referred to as a “multiple small wound group”). Further, in the film or tape, as shown in FIG. 2, a large number of small wound groups are provided at a part of the film or tape, for example, at an end portion, that is, a site intended to start opening. In particular, it is preferable to provide it at the end portions on both sides because it can be torn from both sides.
The small scratch may be a scratch that can start to tear the film, which is a bag material, by hand, regardless of whether the scratch penetrates the material. Any width can be adopted depending on the size of the bag, film, or tape that also uses the width of the belt.
The size and density of individual small scratches and the width of the strip can be arbitrarily selected according to the size and thickness of the film. For example, 0.5 mm scratches can be spaced at 0.5 mm intervals. And what was provided in several rows by turns etc. is mentioned.
In order to provide such a small scratch, a known method can be used, and there is no particular limitation. For example, a disk-shaped or cylindrical rotating grindstone, a wire brush or the like is pressed or scratched with an abrasive. Processing according to known methods disclosed in Japanese Patent Publication No. 61-39228 and Japanese Patent Application Laid-Open No. 61-142133, such as rubbing with a method, laser hole machining method, rotating roller having a large number of blades, etc. Can do.

4). Heat Seal Processing In the bag, film or tape of the present invention, particularly in the bag, it is preferable that the large number of small wound groups are provided in the heat seal portion of the film.
For example, when the bag is a three-side seal type bag, a four-side seal type bag, or a pillow type bag, the bag can be provided in any one of the heat seal portions that perform sealing.
On the other hand, in the case of a bag using an inflation film, heat sealing is usually performed along the side end portion where heat sealing is not performed, and the large number of small wound groups are heated to the side end portion. It can be provided in the seal part. In addition, you may provide not only in the side edge part of a horizontal side but in the heat seal part of a lower end part.
The heat sealing process may be performed simultaneously with the formation process of the small wound group or in separate processes before and after, but it is preferable to perform the heat sealing process first.

5. Production of Bag Using Film The bag according to the present invention can be made into a bag by a conventionally known method using the multilayer film.
As the bag-making, the upper and lower portions of the inflation film formed into a cylindrical shape are heat-sealed to form a bag-packed product, and one side film is used to heat two, three or four sides of the side edge. Examples include a packaging bag to be sealed, a pillow-type bag with the back bonded together, a gusset bag with a gusseted jointed bag, and a standing pouch bag with a devised bottom shape.
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.
As shown in FIG. 1, the process of making a bag from a long film usually performs lower heat sealing with a heat seal roller or the like in a direction perpendicular to the conveying direction while conveying the film in the long direction of the film, It can be performed in the process of cutting the bottom.
The tubular film (1) obtained by inflation molding is heat-sealed (2) at the lower end of the bag under the process of continuous conveyance and cut (6) immediately below to form a bag. The
The bag forming step can be performed in the same step as the step of applying a large number of small wound groups to the side end portion (3) in the longitudinal direction of the packaging bag (3) or in a separate step before and after.
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 (4 in the figure) from the lower side end portion of the upper end heat seal portion.

6). Easy-Tearable Film or Tape The film or tape of the present invention uses the multilayer film as a film material, and the above-mentioned many small wound groups are provided in a band shape at a part that is a planned tear start site.
As shown in FIG. 2, the part may be, for example, an end or may be provided at an arbitrary position other than the end of the film. The direction of the belt can be either vertical or horizontal with respect to the film flow direction.
Examples of the use of the film include a film for shrink wrapping after wrapping an article to be packaged, and a tape obtained by cutting the film into a tape shape.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto without departing from the gist thereof.
For example, the film of the present invention can be obtained by the following layer structure and manufacturing method.
1. Manufacture of blown resin film [used raw materials]
(0) An outer layer / intermediate layer / inner layer three-layer polyethylene multilayer film having the following resin composition was molded by an inflation molding machine with a layer ratio of 1: 1: 1, and an easily tearable film having a film thickness of 30 μm. An inflation film having a certain property was obtained.
Outer layer: ethylene / α-olefin copolymer (LL-1) (MFR: 1.0 (g / 10 min), density: 0.926 g / cm ³ )
Intermediate layer: 70% by weight of ethylene / α-olefin copolymer (LL-1) + 30% by weight of ethylene / cyclic polyolefin copolymer (trade name TOPAS “8007” manufactured by Polyplastics)
Inner layer: ethylene / α-olefin copolymer (LL-2) (MFR: 2.0 (g / 10 min), density: 0.910 g / cm ³ )
The physical properties and measurement method of the obtained inflation film are as follows.
(1) Elmendorf tear strength MD direction (3 N / mm), TD direction (16 N / mm)
The measurement was performed according to JIS K7128-2. Note that MD is a film flow direction (MD: Machine Direction) during film production, and TD is a value in the vertical direction (TD: Transverse Direction).
(2) Impact Drop (DDI: Dart Impact Strength) (DDI): 60 g
The measurement was performed according to JIS K7124-1.
(3) Tensile modulus 1% Tensile modulus: MD direction (490 MPa), TD direction (580 MPa)
The measurement was performed according to JIS K7127. MD and TD are as described above.
2. Bag making process and method for applying a large number of small scratches to the end Using the obtained tubular inflation film, a method for manufacturing a bag and applying a large number of small scratches to the end can be performed by the following method. it can.
A film that becomes a side edge of a bag in a step of transporting a continuously formed tubular inflation film (1) in the longitudinal direction (MD direction of film: 5 in the figure) as shown in FIG. A large number of small wound groups (3) are provided in a strip shape in the vertical direction using a metal roll or the like having a large number of minute sections on the surface in the vertical direction, which is the longitudinal direction.
In this step, a site where the small wound group is provided is heat sealed in advance using a separate heat sealer.
Furthermore, the site | part used as the lower end part of a bag can heat-seal using a separate heat sealer, heat-seal | fuse (2), and can cut | disconnect with a cutting line (6), and can manufacture a bag.
The bag using the inflation film is used as a bag by sealing the upper end after the contents are put in, but has a property of easy opening in the lateral direction (4) when necessary.
In addition, as other three-side seal type bags, four-side seal type bags, pillow type bags, and single films, similarly, by providing a small wound group, an easily openable bag or an easily tearable film can be obtained. it can.

  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., but particularly for use as a bag using an inflation film. It is suitable for a large bag, for example, an inner bag set inside a heavy-weight packaging bag such as a rice bag or a fertilizer bag, or a paper bag. Moreover, as an easily tearable film or tape, it can apply to the film or tape of the use which requires arbitrary hand cutting properties.

Claims (14)

  As a film forming a bag, a large number of small wound groups are formed along side edges or belts of a bag using a multilayer film having a mixed resin layer of a cyclic polyolefin resin and a polyethylene resin at least in an intermediate layer thereof. An easy-open bag characterized by being provided in a band shape.   The easily openable bag according to claim 1, wherein the bag is a bag using an inflation film formed in a cylindrical shape.   The heat seal portion is provided along a side end portion of the bag using the inflation film, and the plurality of small wound groups are provided in the heat seal portion of the side end portion. Easy-to-open bag.   The bag according to claim 1, wherein the bag is a three-side seal type bag, a four-side seal type bag or a pillow type bag, and the plurality of small wound groups are provided in any one of the heat seal portions. Easy-open bag.   The easily openable bag according to any one of claims 1 to 4, wherein the plurality of small wound groups are provided at side end portions on both sides of the bag.   6. The multi-layer film according to claim 1, wherein the multi-layer film is a multi-layer 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. Openable bag. 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 An easily openable bag according to any one of claims 1 to 6, which is a multilayer film containing the inner layer (C).   The easily openable bag according to any one of claims 1 to 7, wherein the multilayer film is a film having an elemental tear tear strength in a TD direction of 50 N / mm or less.   An easily tearable film characterized in that a plurality of small wound groups are provided in a band shape in a part of 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 easily tearable film according to claim 9, wherein the large number of small wound groups are provided at an end of the film.   The easily tearable film according to claim 9, wherein the plurality of small wound groups are provided in a portion other than an end portion of the film.   The easy tear according to any one of claims 9 to 11, 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. Sex film.   The easily tearable film according to any one of claims 9 to 12, wherein the film is a film for shrink wrapping.   An easily tearable tape using the easily tearable film according to any one of claims 9 to 13 as a film constituting the tape.

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