JP2014031218A - Polyethylene packaging box with portion openable by linearly tearing seal opening, and method of manufacturing the same - Google Patents

Abstract

【the purpose】
Regarding a polyethylene packaging bag in which a part of the sealing opening can be opened by linear tearing, when transferring from a polyethylene bag body mainly filled with polished rice to another container, the sealing opening of the tearing part Even if it is torn over the entire length, only a part of the sealing opening is opened so that the filling such as the polished rice does not overflow at once.
[Solution]
In a polyethylene packaging bag in which a part of the sealing opening can be opened by linear tearing, the bag body (1) is formed from a polyethylene film having a property of tearing linearly in one direction, and the upper part of the sealing opening is sealed. A linear heat-sealed part (5 ₁ ), (5 ₂ ) with two steps on the upper and lower sides over the entire length of the lateral width (W) of the stop opening (2) is provided, and the heat-seal part on the upper and lower steps is set to a predetermined height (h) A structure in which a narrow vertical line heat seal part (5 ₃ ) is connected and a notch part is provided for tearing in one direction at a vertical edge between the above two upper and lower heat seal parts. .
[Selection] Figure 1

Description

  The present invention relates to a polyethylene rice or the like that can open a part of a sealing opening that can be opened by linear tearing without using a punch or a cutter knife, etc. When a bag is transferred from a blown polyethylene tube bag mainly filled with rice to another container, it is sealed even if it is torn across the entire width of the opening from the tear portion at the opening. The present invention provides a packaging bag for rice or the like in which only a part of the stop opening is opened so that rice does not overflow. In addition, the filling can be applied to grains other than rice, cultivated soil for horticulture, or humus.

  Generally, when taking out rice from a rice bag containing 1 kg to 10 kg of rice in a polyethylene packaging bag, the lower side of the enclosed linear heat-sealed portion is put along the welded portion, or is torn by hand. Opening is performed.

  The reason for using a manual instrument such as the above-mentioned bag or cutter knife is that the heat seal part at the outlet of the conventional packaging bag is provided on the upper side of the outlet of the three-layer polyethylene tube packaging bag. This is because a high-strength biaxially stretched laminated film is widely used from the viewpoint of durability and the like.

  In addition, the heat seal part at the outlet of the conventional rice bag is provided on the upper side of the outlet of the three-layer polyethylene tube rice bag. Cutting is performed along the side.

  In this case, it can be convenient to tear the opening of the packaging bag by hand without using a bag or a cutter that takes time to open, but from the standpoint of strength and durability of this type of packaging bag High-strength biaxially stretched laminated films are widely used. Therefore, even if a notch or notch is provided at the tear start end at the lower side of the take-out port, it is easy to start tearing the opening, but instead of cutting straight, the tearing direction is not fixed and the tearing direction cannot be determined. It is difficult to cut itself.

  Therefore, it is easy to start tearing opening by providing a notch or notch at the tearing start end below the sealing opening, but from the viewpoint of the strength and durability, a high-strength biaxially stretched laminated film is used. Since it is used, rather than being cut straight, it is difficult to tear it off without being able to determine the direction of tearing, and there is a risk that the tears will flutter and the tears will scatter.

  In view of this, there has been disclosed a packaging bag that can tear the outlet of a synthetic resin film packaging bag laminated in a plurality of layers by hand.

  For example, a bag having a notch in the upper opening part of a bag using a composite film having a seal layer provided on the other side of a first unidirectional tearable film (Patent Document 1), and secondly biaxially stretching What has notches at both ends between the zipper provided on the top of the bag using polyester or polyamide film and the upper seal part (Patent Document 2), and thirdly the top seal part of the packaging bag using unstretched polypropylene film A package with a heat sealing nourishing resin layer made of a polyolefin-based resin laminated on a base sheet having a film of one or more layers (Patent Document 3), and a slit provided for incision for starting tearing at the lower part extending to There is a type in which a band with a tear is provided at the upper part of a sealing bag formed of a material, and a notch is provided at an end of the band (Patent Document 4).

  Fifthly, two rectangular films having a three-layer structure including a film on which a thin film such as aluminum is deposited are overlapped and the peripheral edges thereof are thermally bonded to produce a 120 × 165 (mm) packaging bag, and its accommodation There is a device in which air is sealed as a content together with a ice cream of a spherical ice ball in the part, and an individual take-out part is provided at the take-out port of the content (Patent Document 5).

Japanese Unexamined Patent Publication No. 2004-189912 JP 2002-264950 A JP-A-8-337251 Japanese Utility Model Publication 3-53447 JP 2011-162245 A

  Each packaging bag of Patent Documents 1-4 is easily opened linearly in one direction from the opening start end, but when the opening portion is torn from the start end to the end, all the openings are opened. become. Therefore, it is not suitable for the case where it is desired to transfer the packaged contents to the dispensing.

  In Patent Document 5, since a structure in which two rectangular films having a three-layer structure including a film on which a thin film such as aluminum is deposited is stacked and the periphery thereof is thermally bonded, the periphery of the bag body is welded wide. Then, a part of the sealing opening is opened by tearing the upper part of the bag body along the wide welding portion. On the other hand, in the case of a polyethylene bag not subjected to aluminum vapor deposition as in the present invention, it is difficult to tear the inside of the welded portion linearly.

  Patent Document 5 is a small-capacity packaging bag that contains dozens of ice balls whose contents are about 25 mm in diameter and has a thickness of about 25 mm in order to match the diameter of the ice balls due to the contents. In order to keep it moderate, the bag is inflated by enclosing air inside the bag. On the other hand, in the case of rice bags for distribution, if the rice is filled and sealed as it is, air remains inside and the rice bags swell, and it is slippery to store in a warehouse or to be stacked in stores. There is an inconvenience that collapses. Therefore, a device for removing the residual air in the rice bag has been devised, and it is not preferable to put air into the rice bag together with the filling of rice.

  Accordingly, the present invention provides a packaging bag made of polyethylene rice or the like having a relatively large capacity while enabling the packaging bag that uses a conventional manual instrument to be opened without tearing.

  In the first aspect of the present invention, in a polyethylene packaging bag in which a part of the sealing opening can be opened by linear tearing, the bag body is formed of a polyethylene film having a property of being linearly torn in one direction, A linear heat-sealed portion with steps in two upper and lower stages is provided over the entire width of the upper opening of the sealing opening, and the upper and lower heat-sealed portions are arranged at a predetermined height with a narrow vertical line-shaped heat seal portion. The notch part for connecting and tearing linearly in one direction is provided in the vertical edge between the upper and lower two-stage heat seal parts.

  In the second aspect of the present invention, in a polyethylene packaging bag in which a part of the sealing opening can be opened by linear tearing, a bag body is formed with a polyethylene film having a property of being linearly torn in one direction, A wavy or arcuate non-linear heat seal portion is provided at a predetermined height of the upper and lower steps over the entire width of the upper sealing opening, and an upper welding portion is provided between the predetermined heights of the heat seal portion. A notch is provided.

  According to a third aspect of the present invention, there is provided a polyethylene packaging bag in which a part of the sealing opening according to the first or second invention can be opened by linear tearing. Is provided with a tear notch for tearing in a horizontal direction linearly from the start end to the end.

  According to a fourth aspect of the present invention, there is provided a polyethylene packaging bag in which a part of the sealing opening according to any one of the first to third aspects of the invention can be opened by linear tearing. It is a multilayer polyethylene film having at least a layer containing a polyolefin resin and a polyethylene resin.

  According to a fifth aspect of the present invention, in a polyethylene packaging bag, a part of the sealing opening according to any of the first to fourth inventions can be opened by linear tearing, and the polyethylene film is molded with the polyethylene film. The bag body is processed with an inflation-molded tube body, and the bag body is provided with a notch portion without a welded portion, and a heat seal portion is provided around the notch portion to vent the notch portion and the inside of the bag body. It is characterized by having sex blocked.

  A sixth aspect of the present invention is a method of manufacturing a packaging bag such as polyethylene rice that can open a part of a sealing opening processed by an inflation molded tube body by linear tearing. Sealing the upper opening of the tube body that has the property of tearing linearly, and passing the tear line from the tear start end to the end of the tube body through a part of the heat seal portion, the upper sealing opening A part of is opened.

  A seventh aspect of the present invention is a method of manufacturing a packaging bag such as polyethylene rice that can open a part of a sealing opening processed with an inflation molded tube body by linear tearing. The upper opening of the tube body having the property of tearing linearly is provided with a non-straight line or non-horizontal heat seal part over the entire width of the tube body to seal the opening, and the heat seal part is placed in the middle of the upper and lower stages. The left and right ends are connected with a narrow, vertical line-shaped heat-sealing part to form a stepped shape, or the horizontal and vertical lines that protrude upward in the middle of the horizontal line are roughly trapezoidal. Or an arcuate wavy shape over substantially the entire length of the horizontal width, or an arcuate shape is provided over substantially the entire length of the horizontal width, and the tear line from the tear start end to the end of the tube body It is obtained so as to pass a portion of Lumpur portion.

  8th of this invention manufactures packaging bags, such as a polyethylene-made rice, which can open a part of sealing opening processed with the tube body which carried out the inflation shaping | molding which concerns on 6th invention or 7th invention by linear tearing In the method, the tube body having the property of tearing linearly in one direction is composed of a multilayer polyethylene film having at least a layer containing a cyclic polyolefin resin and a polyethylene resin. is there.

  Since the present invention is configured as described above, the following effects can be obtained. That is, when tearing from the tear start end to the end along the lower side of the linear heat seal portion, the entire sealing opening for extraction is normally opened, but in the present invention, the sealing opening One part or a part of several parts can be opened in a straight line, and rice or other grains or cultivated soil or humus for horticulture can be transferred.

  Finally, the contents of rice or the like remaining in the bag can be taken out by tearing from the notch or the notch located at the lower part of the tearing portion to fully open the sealing opening.

Furthermore, the notch part for partial opening has only one vertical part or two spaced parts in the middle of the tearing direction or several narrowly spaced heat seal parts. Since it is torn at right angles or intersecting, it can be torn off in a straight line from the tear start end to the end without any trouble.
Even if the welded portion is provided in the notch portion, the tearing portion is very small, so there is almost no hindrance to the tearing effect. Furthermore, by providing a heat seal part that surrounds the week of the notch part without providing a welded part at the place where the notch part is provided, the notch part and the inside of the bag body are blocked from air permeability, and tear efficiency Will be improved.

FIG. 1 is a perspective view of a packaging bag made of polyethylene or the like by inflation molding according to the present invention. FIG. 2 is a front view in which a non-linear heat seal portion is formed on the tube body in the inflation molding step of FIG. FIG. 3 is a front view of another embodiment of the non-linear heat seal portion. FIG. 4 is a front view in which a heat seal portion is formed into a trapezoid having approximately isosceles sides provided in the upper portion of the bag body. FIG. 5 is a front view of another embodiment provided with a wavy heat seal portion. FIG. 6 is a front view of another embodiment in which an arcuate heat seal portion is provided. FIG. 7 is an enlarged front view of the narrow vertical heat seal portion and the notch portion in FIG. FIG. 8 is an enlarged cross-sectional view of another embodiment of the notch portion of FIGS. 1 and 7. FIG. 9 is a multilayer enlarged cross-sectional view of a polyethylene multilayer film of three types and three layers of outer layer A / intermediate layer B / inner layer C made of a resin composition.

The form for carrying out the present invention is as follows.
When opening a part of the sealing opening for taking out the filled rice by straight tearing, the sealing opening can be opened when tearing linearly in one direction from the tear start end to the end. A vertical line heat seal that connects the upper and lower two-stage heat seal portions and the end portions thereof is provided so that a part of the heat seal portion can be opened, and a tear line passes through the vertical line shape.

  In a packaging bag such as rice that can be opened partially by tearing the sealing opening linearly, the sealing opening is opened when tearing linearly in one direction from the tearing start end to the end of the bag body. In order to allow a part of the heat seal to be opened, the heat seal portion is formed in a non-linear shape having an arc shape or a wave shape.

  In this packaging bag of rice or the like, a welded portion for forming a notch portion for tearing is provided at the upper and lower portions of the longitudinal end of the bag body, and this proceeds linearly horizontally from the start end to the end. A notch for tearing is provided.

  As the film having the property of tearing linearly in one direction used in the present invention, it is particularly preferable to use a multilayer polyethylene film having at least a layer containing a cyclic polyolefin resin and a polyethylene resin.

The film is an easily tearable multilayer film having excellent longitudinal and lateral tearability and also having impact strength. As a preferred embodiment, polyethylene having a density of 0.870 to 0.935 g / cm ³ is used. The outer layer (A) whose main component is (a), the cyclic olefin resin (b1) 10 to 90% by weight, and the low density polyethylene (b2) 10 to 90 having a density of 0.870 to 0.935 g / cm ³ . 3 layers or more having at least an intermediate layer (B) whose resin main component is a resin consisting of% by weight and an inner layer (C) whose main component is a polyethylene (c) having a density of 0.870 to 0.935 g / cm 3 The multilayer film is mentioned. As the cyclic olefin-based resin, an ethylene / cyclic olefin copolymer is preferably exemplified.

Next, embodiments of the present invention will be described with reference to the drawings.
1, 2, and 3 are rice bags for 5 kg of polished rice, and 1 is a bag made of a polyethylene tube t having a property of being linearly torn in one direction after inflation molding, The upper part in the L direction is the sealing opening 2, and the lower opening 3 'is welded along the edge of the bag body after the contents such as rice are stored to form the bottomed part 3. Reference numeral 4 denotes a vertical side of the bag body, and two notch weld portions for upper and lower portions are provided on both sides or one side thereof.

Reference numeral 5 denotes a heat seal portion for sealing the opening 2 of the bag body 1. 1 and 2, 5 ₁ and 5 ₂ are provided with a horizontal line-shaped heat seal portion 5 ₁ and 5 ₂ with a predetermined height h over the entire width W of the bag body 1 at a predetermined height h, and between the upper and lower sides thereof. has a substantially crank-shaped connecting the height h in the vertical line-shaped heat-sealed portion 5 _3.

Reference numerals 5 'and 5 "designate notch portions forming welds provided on the upper and lower two sides of the bag body vertical side 4. Reference numeral 6 designates a tear notch portion provided on the upper weld portion 5'. This is a tear notch provided in the lower welded part 5 ″. The notch portions 6 and 6 'are laterally V-shaped (shown by a solid line in FIG. 7) or a single horizontal character shape (shown by a solid line in FIG. 8). Hereinafter, both shapes are collectively referred to as notch portions.
In FIG. 8, the notched portions 6 and 6 ′ are provided directly on the bag body 1 without providing the welded portion at the position where the notched portion is provided, and the heat seal portion 5 n is surrounded by surrounding the notched portion. The air permeability between the notches 6 and 6 ′ and the inside of the bag body 1 is blocked.

Vertical linear hot sealing portion 5 ₃ of the above straight become the its sealing linear wider the vertical line-shaped heat-sealed portion 5 ₃ Faulty tearing straight across in its height h There is a risk of tearing. Therefore, the vertical line-shaped heat-sealed portion _3, narrow w enough to cut easily tear linearly from the notch portion 6 and the upper without affecting the sealing of the opening 2 '(0.5-1. It is desirable to form in about 5 mm.

Note that the vertical line-shaped heat-sealed portion 5 ₃ of the addition of the vertical lines (FIGS. 1-3 and 7) and inclined lines (FIG. 4), is intended to include inclined arch-shaped (FIGS. 5 and 6) . A plurality of heat seal 5 ₃ inclined arcuate line of the In the wave line shape (FIG. 5) or arch-shaped (FIG. 6), there is no hindrance to tear because always appropriate intervals is maintained.

  Further, the area ratio of the welded portions 5 'and 5 "to the notch portion 6 is as small as possible. Specifically, the tip of the notched portions 6 and 6' and the edge of the welded portions 5 'and 5" The width w ″ is set within 0.5 to 2.0 mm. 7 is an extra piece located above the upper notch portion 6 of the bag body 1.

Figure 3 is the top of the bag body 1, connecting the heat-sealed portion 5 _1, 5 ₂ of the horizontal linear with narrow in the central portion in the vertical line-shaped heat-sealed portion ₃ with a two upper and lower stages stage, Figure 1・ It has almost the same shape as 2.

Figure 4 shows one formed trapezoidal by molding a substantially central portion on the inclined line-shaped heat-sealed portion ₃ at the isosceles narrow the bag 1.

Figure 5 is a wavy-line heat seal portions 5 _1, 5 ₂ provided at a predetermined height h over the entire width W of the bag body 1, there is a tear notch 6 between the height h provided. Then, it is provided with a tear notch 6 immediately below the wave line-shaped heat-sealed portion 5 ₂ '.

Figure 6 is a archwire shaped heat-sealed portion 5 _1, 5 ₂ provided at a predetermined height h over the entire width W of the bag body 1, the welding portion of the vertical side 4 of the position passing through the arcuate oblique line ₃ of the inside height h A tearing notch 6 is provided at 5 '. Then, is provided with a lower weld portion 5 "with tear notch 6 'immediately below the heat-sealed portion 5 ₂ of archwire shaped lower portion.

The notch part 6 is a notch part for extending a part of the heat seal parts 5 ₁ and 5 ₂ and tearing and opening a part 2 ′ of the sealing opening 2. A heat seal is formed simultaneously with the formation of the heat seal portion 5 for forming the bottom portion 3 of the next bag body at the notch forming portion, and the notch portion 6 is formed.

"Specific rice bag production process and rice filling / removal example"
(1) Three types and three layers of polyethylene multi-layer films of outer layer A / intermediate layer B / inner layer C having the following resin composition were molded by an inflation molding machine to obtain a tube body having a property of tearing linearly in one direction. .
Outer layer A: ethylene / α-olefin copolymer (LL-1) (MFR: 1.0 (g / 10 min), density: 0.926 g / cm ³ ) (a)
Intermediate layer B: 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) (b ₁ ) · (b ₂ )
Inner layer C: ethylene / α-olefin copolymer (LL-2) (MFR: 2.0 (g / 10 min), density: 0.910 g / cm ³ ) (c). A three-layer, three-layer polyethylene multilayer film of outer layer A / intermediate layer B / inner layer C having a resin composition is shown in FIG.
(2) A polyethylene tube body t having the property of being linearly torn in one direction obtained by the inflation molding is set on a known bag making machine and set to a predetermined size (for example, 5 kg of polished rice, height H 470 mm × width 280 mm). It was among the top sealing longitudinal edges of the one end of the opening 2 of the heat-sealed portion 5 of the total width W (280 mm), the third of (about 93 mm) horizontal linear hot sealing portion of the upper in the width w 'of about 5 ₁ provided, the vertical line-shaped heat-sealed portion ₃ with uneven from the end portion is molded at a predetermined height h, the lowered lower horizontal linear heat of connecting the end portion to the vertical line-shaped heat-sealed portion ₃ to the position the seal portion 5 ₂ is molded, is provided with the tear notch section 6.6 directly below and between the height h lower heat seal portion 5 ₂ '(FIGS. 1, 2, 7).
(3) Next, rice (for example, 5 kg of polished rice) is filled from the opening 3 ′ on the lower side of the bag body 1.
(4) The lower side opening 3 ′ of the bag 1 filled with rice is heat-sealed and sealed to make the sealing part the bottom 3.
(5) When removing the polished rice filled in the bag 1 for transfer, from the notch portion 6 of the tear start end x between the upper and lower horizontal linear heat seal portions 5 ₁ and 5 ₂ along the imaginary line 1 as it tears, straight to reach the tear end y of the opposed side while passing through the vertical line-shaped heat-sealed portion _3, only part 2 ₁ of the sealing aperture 2 is opened. At the same time, the surplus piece 7 is separated from the bag body 1.
(6) Finally retrieve the remaining amount of the contents to fully open the seal opening 2 '' from the virtual line l 'notches 6 located immediately below the lower heat-sealed portion 5 ₂ tearing along.

The following is another example of the heat seal portion 5 in the upper opening portion of the bag body 1 of paragraph (0043) (0043).
“No. 1”: A vertical line-shaped heat seal portion 5 at a position half the full width W of the upper and lower horizontal linear heat seal portions 5 ₁ and 5 ₂ at a predetermined height h at the upper portion of the bag body 1. ₃ is formed into a substantially crank shape (a shape in which the left and right cranks are connected by a crankshaft), the entire width W of the opening 2 is sealed, and a tearing notch 6 is provided between the heights h (see FIG. 3). In this case, part of the sealing aperture 2 2 ₁ is opened.
"Part 2": bag for about 5 minutes heat-sealed portion 5 ₁ 1 about a horizontal line-shaped full width provided in the upper central portion of the 1, molding the inclined longitudinal line-shaped heat-sealed portion 5 ₂ at both ends seals the entire width W of the opening 2 by the lower horizontal line-shaped heat-sealed portion 5 _2, in which the tear notch 6 between the height h of the peaks and valleys are provided (FIG. 4). In this case, part of the central portion of the sealing aperture 2 ₁ is opened.
“No. 3”: A wavy heat seal portion 5 ₁ , 5 ₂ that forms an arc shape with a predetermined height h over the entire width W of the bag body 1 is provided, and a tear notch portion is provided between the height h. 6 is provided (FIG. 5). In this case, only the sealing aperture 2 ₁ portion of crest is opened.
“No. 4”: Arc-shaped heat seal portions 5 ₁ and 5 ₂ are provided at a predetermined height h over the entire width W of the bag body 1, and a tearing notch portion 6 is provided between the heights h. (FIG. 6). In this case, only the central peak portion 5 ₁ of the portion of the sealing aperture 2 is sealing the opening 2 ₁ is opened over the width w _1.

  The present invention is mainly applied to a packaging bag of polished rice of about 5 kg, but a relatively large capacity other than a packaging bag polished rice of a relatively small capacity or a large capacity of about 7 kg to 10 kg as a rice bag of about 1 kg to 3 kg. It can also be used as a storage bag for cultivated soil and humus for grain and horticulture. It can also be used as a packaging bag for other fillings.

DESCRIPTION OF SYMBOLS 1 ... Bag body 2 ... Sealing opening 2 ₁ ... Part of sealing opening (upper stage)
DESCRIPTION OF SYMBOLS 3 ... Bottom part 4 ... Vertical side of bag body 5 ... Heat seal part 5 ₁ ... Upper heat seal part 5 ₂ ... Lower heat seal part 5 _n ... Heat seal part surrounding notch part without welding part 5 '... For upper notch part Welding part 5 ″… Welding part for lower notch part 6… Upper notch part (including notch part)
6 '... Lower notch (including notch)
7 ... Surplus piece of tearing part

Claims (8)

A bag body (1) is formed from a polyethylene film having a property of tearing linearly in one direction, and a stepped linear shape over the entire width (W) of the upper sealing opening (2). The heat seal portions (5 ₁ ) and (5 ₂ ) are provided, and the upper and lower heat seal portions (5 ₁ ) and (5 ₂ ) are arranged at a predetermined height (h) with a narrow vertical line heat seal portion. (5 ₃ ), provided with a notch (6) for tearing linearly in one direction on the vertical edge between the _two upper and lower heat seal parts (5 ₁ ) and (5 ₂ ) A packaging bag made of polyethylene in which a part of the sealing opening can be opened by linear tearing. A bag body (1) is formed from a polyethylene film having a property of tearing linearly in one direction, and a predetermined height (h) of the upper and lower stages over the entire width (W) of the upper sealing opening (2). ) Is provided with a wavy or arcuate non-linear heat seal portion (5), and an upper notch portion (6) is provided between the predetermined height (h) of the heat seal portion (5 ₁ ) for sealing. A polyethylene packaging bag whose opening can be partially opened by linear tearing.   The sealing notch part (6) according to claim 1 or 2, wherein a tearing notch part (6) or a tearing notch part (6 ') for tearing in a horizontal direction linearly from the start end to the terminal end is provided at a lower position of the notch. A polyethylene packaging bag whose opening can be partially opened by linear tearing.   The sealing film according to any one of claims 1 to 3, wherein the polyethylene film is a multilayer polyethylene film having at least a layer containing a cyclic polyolefin resin and a polyethylene resin. A polyethylene packaging bag that can be partially opened by tearing the shape.   A bag body (1) molded with the polyethylene film is processed with an inflation molded tube body (t), and the bag body (1) is provided with notched portions (6) and (6 ') without a welded portion. Further, a heat seal part (5n) is provided so as to surround the notch parts (6) and (6 '), and the air permeability between the notch part and the bag body is blocked. 4. A polyethylene packaging bag capable of partially opening the sealing opening according to any one of 4 by linear tearing.   The upper opening part of the tube body that has the property of tearing linearly in one direction forming the bag body is provided with a non-straight or non-horizontal heat seal portion over the entire width of the tube body to seal the opening, and the tube An inflation molded tube body characterized in that a part of the upper sealing opening is opened by passing a tear line from the tear start end to the end of the body through a part of the heat seal part. A method for producing a packaging bag made of polyethylene rice or the like, wherein a part of the sealing opening processed in step 1 can be opened by linear tearing. The upper opening part of the tube body that has the property of tearing linearly in one direction forming the bag body is provided with a non-straight or non-horizontal heat seal portion over the entire width of the tube body to seal the upper opening, The heat seal part is provided in the middle of the upper and lower stages, and the left and right end parts are connected with a narrow and vertical line heat seal part to form a step, or the left and right narrow widths projecting upward in the middle of the horizontal line Form a substantially trapezoidal shape with a vertical line and a horizontal line, or form an arcuate wavy line over substantially the entire length of the horizontal width, or provide an arc line shape over the substantially entire length of the horizontal width, and start tearing of the tube body Inflation molding is characterized in that a part (2 ₁ ) of the upper sealing opening (2) is opened by passing a part of the heat seal part through a tear line from the end to the end. Sealed opening processed with tube body Method for producing a packaging bag made of polyethylene such as rice that can open the part by linear tear.   The tube body having a property of being linearly torn in one direction is composed of a multilayer polyethylene film having at least a layer containing a cyclic polyolefin resin and a polyethylene resin. Item 8. A method for producing a packaging bag made of polyethylene rice or the like, wherein a part of a sealing opening processed with an inflation-molded tube body according to Item 7 can be opened by linear tearing.