JP2894857B2 - Easy-open bag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a bag having a sealing band that can be easily opened.

[0002]

2. Description of the Related Art In a conventional bag body, a sealing band is bent at a central portion, attached so as to cover a bag body portion, and sewn with a sewing machine. However, the paper bag sewn with the sewing machine has a sufficient strength of the sealing portion, but the sealing property is insufficient, and foreign matter enters through the perforation to contaminate the contents, or conversely, the contents are powder. In some cases, there are drawbacks such as that the powder is blown out of the bag and the opening operation is complicated due to the difficulty in unraveling the sewing thread.

[0003] In order to solve such a drawback of the paper bag, Japanese Utility Model Application Laid-open No. 64-20451 discloses an easily openable paper bag in which a sealing band with a string for opening is adhered to an opening. However, although this paper bag is excellent in hermeticity and openability, it is difficult to use a high-strength material for the encapsulation band because the encapsulation band is cut open with an opening string, and thus the paper bag is easily torn. Vulnerable to falling shocks that exert force on Therefore, it is not suitable for a gusseted paper container whose content weight tends to be heavy, and the use of this paper bag has been considerably limited. Further, since the sealing band is cut open with a string at the time of opening, there is a problem that notches may be formed in the cuts or zigzag cuts and paper powder may be generated, thereby contaminating the contents of the bag.

Further, in the case of a tape to which kraft paper is laminated, the moisture of the kraft paper evaporates during lamination and heat-sealing to the main body and becomes moro. When the tape passes through a sealer, it is strongly bent and creased. Therefore, in the dry season from autumn to winter, there is a problem that the kraft paper outside the bag body is cracked, which causes the bag to break.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a bag which solves the above-mentioned drawbacks of the conventional paper bag, has a high strength and tightness, and has a sealing band which can be easily opened.

[0006]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a vertically elongated sealing band having a length at both ends of the width of the bag body, and an opening of the bag body. It is a bag body that is adhesively sealed so that it is sandwiched, and this sealing band is laminated in the order of kraft paper, a laminated resin layer, a cross sheet layer woven of flat yarn, and a thermal adhesive layer, and it is continuous at the center on the thermal adhesive layer. The bag is provided with a sealing band to which the opened string is adhered.

[0007] The bag body used in the present invention is a normal bag body conventionally used in the manufacture of a bag, wherein the paper or synthetic resin sheet has a single layer or a multi-layer, and furthermore, a synthetic resin. A sheet having a reinforcing material such as a sheet or a woven fabric can be used. The shape of the bag body is shown in FIG.
In addition to the gusseted one as shown in FIG.

The basis weight of the kraft paper used in the present invention varies depending on the use of the sealing band, but is generally 50 to 75 g / m ^2.
It is. The laminating resin used for the laminating resin layer of the present invention is a resin capable of binding the kraft paper and the cloth sheet layer, and includes, for example, high-density polyethylene, low-density polyethylene, cotton-like low-density polyethylene, and ethylene-vinyl acetate copolymer. Can be mentioned. This laminated resin is applied on kraft paper by a conventional method at 10 to 40 g / m
² , preferably 15 to 20 g / m ² .

The cross sheet layer of the present invention is generally a cross sheet obtained by plain weaving flat yarn of high density polyethylene. This high-density polyethylene has an MFR of 0.5
A density of 0.942 to 0.965 g / cm ³ is used. The material of the flat yarn is not limited to high-density polyethylene, but may be polypropylene, polyester, polyamide resin, or the like. However, high-density polyethylene is preferable because it can be easily laminated and is inexpensive.

The warp used is a flat yarn having a denier of 75 to 500, a width of 0.5 to 2.0, preferably 100 to 300 denier and a width of 0.6 to 1.6 mm. The number of warp yarns is generally 13 to 60 yarns / inch, preferably 16 to 46 yarns / inch. The warp yarns are preferably driven tightly so as to overlap. This is because the warp flat yarn is partially overlapped and driven without gaps, which not only increases the strength of the cross sheet layer, but also strongly fixes the weft, so the cutting force of the opened string is concentrated at one point of the weft. This is because the weft is easily cut, and a straight cut is obtained.

The weft used is a flat yarn having a denier of 100 to 350 and a width of 0.6 to 1.8 mm, preferably 200 to 300 denier and a width of 1.0 to 1.6 mm. The number of wefts to be driven is 8 to 25 / inch,
Preferably, it is 10 to 18 lines / inch. The reason for limiting the width of the weft is to prevent the weft from being folded during weaving. The intersection of the weft and the warp may or may not be heat-bonded using a multi-layer flat yarn having a low-melting resin layer on the surface as necessary. In addition, in order to reduce the burden on the opening string and prevent the string from being broken during opening, a weft yarn having a strength lower than that of the opening string is used. Its strength is one of the strength of the string for opening.
/ 5 to 1/7.

The use of the flat yarn for the cross sheet layer as described above makes the sealing band lighter and more flexible than the spun yarn or synthetic fiber monofilament or multifilament, and is excellent while maintaining the desired strength. This is because openability is obtained, and the opened cut is smooth and paper powder, fiber powder, laminate resin and the like do not fall off.

The resin used for the heat bonding layer of the present invention is a resin for bonding a string for opening to the cloth sheet layer and for thermally bonding the sealing band to the opening of the bag body.
Therefore, a resin having good thermal adhesion is used. For example, low-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer and modified polyethylene can be mentioned, and among them, ethylene-vinyl acetate copolymer resin (EVA resin) is particularly preferable. This resin is laminated on the cloth sheet layer by a conventional method so as to have a thickness of 15 to 40 g / m ² , preferably 20 to 30 g / m ² .

The string for opening used in the present invention is not particularly limited as long as it has sufficient strength to cut the sealing band, but a flat denier flat yarn made of polypropylene or high-density polyethylene is preferable. This flat yarn has a denier of 500 to 2,000, a width of 1 to 6 mm,
Preferably 800-1200 denier, width 1.5
４4 mm can be used. This string for opening is adhered on the thermal adhesive layer by a laminate resin. Preferably, they are bonded by extrusion lamination.

The laminate thus constructed is cut into a rectangle so that extra lengths of 2 to 6 cm are formed on both sides of the bag body. Then, as shown in FIG. 2, the sealing band 6 is folded in a V-shape almost at the center, and the both ends of the bag body 7 are covered with extra length portions. 100 to 18 so that the sealing band 6 and the bag body 7 adhere to each other.
Heat to 0 ° C. The sealing band seals one or both of the openings of the bag body. When only one of the openings of the bag body is sealed with the sealing band of the present invention, the other is closed by sewing or a normal sealing band.

In the sealing band of the present invention, tearing is performed while pulling up the extra length portion, leaving the opened string, and moving the opened string along the bag body to break the sealing band and open.

[0017]

According to the present invention, it is possible to obtain a bag having a sealing band which is high in strength and sealing property and easy to open.

[0018]

EXAMPLE 73 g / m2 for the production of a sealing band^Two Craft
Low-density polyethylene (M
FR 7.0, density 0.917 g / cm^Three ) At 15 g / m^Two Tona
In addition, high density polyethylene (MFR)
0.8, density 0.954g / cm ^Three 0.85mm width, 115
Denier flat yarn, the same high density as the warp for the weft
Degree polyester, width 1.2mm, 215 denier, strong
Using flat yarn of 1.1kg degree, 13.0 warps / cm
(33 yarns / inch), 4.7 yarns / cm (12 yarns / inch)
(H) The cross sheet is driven in at the ratio of
24 g / m of EVA resin as a layer^Two Use
Was. Further, a triple kraft paper (weighing 7
5g / m^Two ), The opening string has a width of 2.1 mm,
Uses 1000 denier flat yarn with a strength of 5.8 kg
did.

The production of the sealing band is performed by first laminating the kraft stretched paper and the flat yarn with a laminator sandwiching the molten laminated resin therebetween, and further laminating the molten EVA-based resin on the laminated body with a laminator. The opened string was adhered, and then the laminate was cut with a slitter so that the opened string was located at the center, to obtain a sealing band having a desired width.

The sealing band thus obtained was heat-sealed to the opening of the bag body with the gusset folded as shown in FIG. 2 using a heat sealer to make a bag. Further, the bag was filled with 25 kg of resin pellets as contents and sealed as described above. Next, the paper bag described in the example was weighed at 75 g / m ^2.
Using a conventional paper bag having a conventional sealing band with two layers of kraft paper laminated and bonded in the center with a thread-like opening string, a drop test and a difficulty test of opening were performed. This conventional sealing band was also laminated using an EVA-based resin, and was thermally bonded to the opening of the bag body with a heat sealer to make a bag. Test conditions Drop test The drop was repeated until the sealing band was damaged and the contents came out. (1) Bag Size 800 mm × 470 mm × 100 mm attached gusset (2) drop height 1.2 m (3) contents of resin pellets 25 kg (4) body Kraft paper 75 g / m ^2, 3-layer bag 2. Opening difficulty test (1) Opening difficulty ○ Good △ Caught ×
String break or inability to open (2) Opening quality ○ Straight and sharp △ Zigzag or notch × Propagation result (1) Drop test (average per 10 bags) Horizontal drop Oblique drop Sealing band of the example 10 times * 5 times Conventional sealing band 4 times 1 time * Canceled because 10 times were cleared. (2) Opening difficulty test Example Conventional product Opening difficulty ○ ○ Opening quality ○ △

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state of each layer of a sealing band according to the present invention.

FIG. 2 is a conceptual diagram of the bag of the present invention in a step of attaching a sealing band.

[Description of Signs] 1 Kraft paper 2 Laminated resin layer 3 Cross sheet layer 4 Thermal bonding layer 5 Opening strap 6 Sealing band before installation 7 Bag body 8 Gazette

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-183856 (JP, A) JP-A 64-20451 (JP, U) JP-A 48-40690 (JP, Y1) (58) Field (Int.Cl. ⁶ , DB name) B65D 33/00-33/38

Claims (2)

(57) [Claims] 1. A bag body in which a vertically long sealing band having a length that produces extra lengths at both ends of the width of the bag body is adhesively sealed so as to sandwich an opening of the bag body. The band is laminated in the order of kraft paper, a laminated resin layer, a cross sheet layer woven of flat yarn, and a heat bonding layer, and it is a sealing band in which the opening string is continuously bonded to the center of the heat bonding layer. The said bag characterized by the above-mentioned. 2. The use of a sealing band having a cross-sheet layer in which the number of warp yarns is greater than the number of weft yarns, the warp yarns are arranged without gaps, and the weft yarns are flat yarns lower in strength than the opened string. Item 7. The bag according to Item 1.