JP2011240980A - Packaging bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging bag which can be resealed inexpensively and easily.SOLUTION: The packaging bag includes a packaging bag body having unsealed part at one side, wherein a sheet-shaped or a rod-shaped shape-retaining material is laminated in a substantially vertical direction to the unsealed part. The shape-retaining material consists of a stretched polyolefin resin sheet or a rod and has shape-retaining properties, wherein return angles θ are both 20° or less when 5 minutes has passed since the shape-retaining material was released after being folded at 180° or 90° in the longitudinal direction and the substantially vertical direction and was held for one minute.

Description

  The present invention relates to a packaging bag that can be easily resealed after the contents are taken out.

  Conventionally, cylindrical plastic bags have been used as bags for packaging snacks and the like. When these bags are opened and the contents are taken out, it is common for some of the contents to remain, in which case they need to be resealed. When resealing, it is common to fold or squeeze the opening and reseal it with rubber band or plastic wire. However, it is troublesome because it is necessary to prepare rubber band or plastic wire. In order to eliminate this drawback, a packaging bag (for example, refer to Patent Document 1) with a reseal zipper has been proposed. However, as a packaging bag for packaging inexpensive snacks, etc., the cost is low. There is a drawback that it is difficult to use because of high.

JP 2006-264746 A

  In view of the above problems, an object of the present invention is to provide a packaging bag that is inexpensive and can be easily resealed.

  That is, in the present invention, a sheet-shaped or rod-shaped shape retaining material is laminated in a direction substantially perpendicular to the unsealed portion on a packaging bag body having an unsealed portion on one side, and the shape retaining material is stretched. It consists of a polyolefin-based resin sheet or rod, bent at 180 degrees or 90 degrees in a direction substantially perpendicular to the length direction, held for 1 minute and then released, and the folding return angle θ when both passed for 5 minutes was 20 The present invention relates to a packaging bag characterized by having a shape-retaining property of less than 1 degree.

  The configuration of the packaging bag of the present invention is as described above, is easy to manufacture, is inexpensive, and can be easily resealed simply by folding after opening.

It is a top view which shows an example of the packaging bag of this invention.

  In the packaging bag of the present invention, a sheet-shaped or rod-shaped shape retaining material is laminated in a direction substantially perpendicular to the unsealed portion on a packaging bag body having an unsealed portion on one side. It consists of a stretched polyolefin resin sheet or rod, bent at 180 ° or 90 ° in a direction substantially perpendicular to the length direction, held for 1 minute, released, and the folding return angle θ when 5 minutes passed after release is both It has a shape retention of 20 degrees or less.

  Next, a description will be given with reference to the drawings. FIG. 1 is a plan view showing an example of the packaging bag of the present invention.

  In the figure, reference numeral 1 denotes a packaging bag body in which a substantially rectangular film material is bent into a cylindrical shape, and both ends thereof are joined and bonded to form a joined seal part 2 and the bottom part is adhered to the bottom seal part 3. Is formed into a bag shape, and the upper side is opened to form an unsealed portion 4. In the packaging bag body 1, a shape-retaining material 5 is laminated in the direction from the unsealed portion 4 to the bottom seal portion 3 in a direction substantially perpendicular to the unsealed portion 4.

  The unsealed portion 4 is a portion that opens and fills the packaging bag with a predetermined content and then adheres and seals the packaging bag. When the content is taken out, it is cut to open the packaging bag. Therefore, it is preferable that the shape-retaining material 5 is laminated in the direction of the bottom seal portion 3 from below the unsealed portion 4.

  The film material forming the packaging bag body is not particularly limited as long as it is a film conventionally used for packaging bags for packaging snacks and the like. For example, biaxially stretched polypropylene film, biaxially stretched polyester Examples thereof include films, biaxially stretched nylon films, moisture-proof cellophane, aluminum-deposited polyester films, aluminum-deposited polypropylene films, and inorganic oxide-deposited polyester films.

  For the film material, for example, an unstretched nylon film, an aluminum foil, an ethylene-vinyl alcohol copolymer film, a polyvinylidene chloride film, a polyacrylic resin, in order to impart a gas barrier property to the film material or improve the mechanical strength. A nitrile film, vinylidene chloride resin coated cellophane, or the like may be laminated. When the film material is heat-sealed to form the palm seal part 2 or the bottom seal part 3, for example, a low density polyethylene resin, a medium density polyethylene resin, a linear low density polyethylene resin, ethylene-vinyl acetate It is preferable that a heat-fusible resin layer such as a copolymer, a homopolypropylene resin, a propylene-ethylene random copolymer, a propylene-ethylene block copolymer, or a polypropylene-α-olefin copolymer is laminated.

  The shape-retaining material 5 is made of a stretched polyolefin resin sheet or rod, bent at 180 degrees or 90 degrees in a direction substantially perpendicular to the length direction and held for 1 minute and then released, and when 5 minutes have passed since the release. Both of the bending return angles θ have shape retention of 20 degrees or less.

  The shape retention of the stretched polyolefin resin sheet or rod is released after holding the stretched polyolefin resin sheet or rod at 180 degrees or 90 degrees in the direction perpendicular to the stretch direction for 1 minute, and then 5 minutes after release. The bending return angle θ is 20 degrees or less, preferably the 180-degree bending return angle θ is 20 degrees or less, and the 90-degree bending return angle θ is less than 20 degrees, more preferably 180-degree bending. The return angle θ is 20 degrees or less and the 90-degree bending return angle θ is 15 degrees or less. If one of the bending return angles θ at the time of 180-degree and 90-degree bending, particularly the 90-degree bending return angle θ exceeds 20 degrees, sufficient shape retention may not be obtained.

  As the polyolefin-based resin constituting the stretched polyolefin-based resin sheet or rod, any olefin-based resin having film forming ability can be used, for example, a high-density polyethylene resin, a medium-density polyethylene resin, a low-density polyethylene resin, a linear shape Low density polyethylene resin, polypropylene resin, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-pentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer , Ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-propylene-butene copolymer, etc., and high density polyethylene resin and polypropylene resin. Preferably used.

  When the weight average molecular weight of the polyolefin resin is less than 100,000, the polyolefin resin becomes brittle and the stretchability is lowered, or a stretched polyolefin resin sheet having sufficient mechanical strength or creep resistance is obtained. On the contrary, when it exceeds 500,000, the melt viscosity becomes high, the hot melt molding processability is lowered, and it becomes difficult to obtain a uniform sheet, and therefore 100,000 to 500,000 is preferable. In the present invention, the weight average molecular weight is a value measured by gel permeation chromatography (GPC).

The melt index (hereinafter referred to as MI) of the polyolefin resin is preferably from 0.1 to 20 (g / 10 minutes), more preferably from 0.2 to 10 (g / 10 minutes), which is excellent in film moldability. It is. MI is an index representing the melt viscosity of a thermoplastic resin specified in JIS K 7210. Furthermore, in the case of a high density polyethylene resin, 0.94 g / cm ³ or more is preferable because the mechanical strength does not improve even if the density is reduced even if the density is reduced.

  As the stretched polyolefin resin sheet, a stretched polyolefin resin sheet having a shape-retaining property in which a polyolefin resin sheet having a weight average molecular weight of 100,000 to 500,000 is uniaxially stretched at a stretch ratio of 5 times or more is preferable.

  In this case, the polyolefin resin is preferably a high-density polyethylene resin having an intrinsic viscosity [η] of less than 3.5 dl / g, such as glass fiber, talc, mica, calcium carbonate, magnesium hydroxide, alumina, zinc oxide, magnesium oxide, It is preferable to add inorganic machine fillers such as aluminum hydroxide, silica alumina, titanium oxide, calcium oxide, calcium silicate, basic magnesium carbonate, carbon fiber, and carbon black.

  The thickness of the polyolefin resin sheet before stretching is not particularly limited, but if it is too thick, stretching becomes difficult. Conversely, if it is too thin, the thickness of the polyolefin resin sheet after stretching becomes too thin. Since shape retainability deteriorates, 0.2 to 5.0 mm is desirable.

  The stretched polyolefin resin sheet that has been stretched may have a stretch ratio of 5 times or more and have shape retention, but is preferably 10 to 40 times. The stretching method may be any conventionally known method, such as a method of stretching while heating with a heater or hot air by a uniaxial stretching method such as a roll uniaxial stretching method or a zone uniaxial stretching method. .

  When stretching uniaxially to a high degree of 10 to 40 times, a multistage uniaxial stretching method in which uniaxial stretching is repeated a plurality of times is preferable. When performing multistage uniaxial stretching, the number of stretching is preferably 2 to 20 times, more preferably 3 to 15 times, still more preferably 4 to 10 times. When performing multi-stage stretching by a roll uniaxial stretching method, it is desirable to install a feeding pinch roll, a take-up pinch roll, and at least one, preferably a plurality of contact rolls that rotate at a constant speed between these rolls. By installing such a contact roll, uniform stretchability is improved and stable stretch molding can be performed.

  The contact roll performs uniaxial stretching by applying a frictional force to the polyolefin resin sheet without being pinched. Further, the contact roll may be connected to the feeding roll and / or the take-up roll by a connecting member made of a gear, a chain, a pulley, a belt, or a combination thereof.

  The uniaxial stretching temperature cannot be uniformly stretched when it is low, and the sheet melts and cuts when it is high. Therefore, the range of “melting point−60 ° C.” to the melting point of the polyolefin resin of the polyolefin resin sheet to be stretched is more preferable, It is “melting point−50 ° C.” to “melting point−5 ° C.” of the polyolefin resin.

  In order to improve the dimensional stability of the stretched polyolefin resin sheet, the stretched polyolefin resin sheet may be annealed at a temperature between “melting point−60 ° C.” and melting point of the polyolefin resin. If the annealing temperature is lowered, the dimensional stability will not improve, warping will occur if used for a long time, and if it is raised, the polyolefin resin will dissolve and the orientation will disappear and the tensile modulus, tensile strength, etc. will decrease. It is preferable to anneal the resin at a temperature ranging from “melting point −60 ° C.” to the melting point.

  Annealing is a heat treatment in the production line. When annealing, the stretched polyolefin resin sheet is stretched if a large tension is applied, and it is not stretched or shrinks in a very small state. The length of the stretched polyolefin resin sheet in the stretching direction is preferably substantially unchanged, and it is preferable that no pressure is applied to the stretched polyolefin resin sheet. That is, it is preferable to anneal so that the length of the annealed stretched polyolefin resin sheet is 1.0 or less of the length of the stretched polyolefin resin sheet before annealing.

  Accordingly, when the stretched polyolefin resin sheet is continuously annealed while being moved in the heating chamber with a roll such as a pinch roll, the feed rate ratio of the polyolefin resin sheet on the inlet side and the outlet side is 1.0 or less. It is preferable to anneal with setting.

  The heating method at the time of annealing is not particularly limited, and examples thereof include a method of heating with hot air, a heater, a heating plate, hot water or the like. The time for annealing is not particularly limited, and varies depending on the thickness of the stretched polyolefin resin sheet and the annealing temperature, but is generally preferably 10 seconds or more, more preferably 30 seconds to 60 minutes, and still more preferably 1 to 20 Minutes.

  Further, as a different preferred stretched polyolefin resin sheet, a polyolefin resin sheet having a weight average molecular weight of 100,000 to 500,000 was rolled to a rolling ratio of 5 times or more, and then the total stretching ratio was uniaxially stretched to 10 to 40 times. A stretched polyolefin resin sheet may be mentioned.

  The thickness of the polyolefin-based resin sheet before rolling is not particularly limited, but if it is too thick, stretching becomes difficult, and in the rolling process, a large pressing force is required to crush the polyolefin-based resin sheet with a rolling roll. Take-up force is required, and uniform rolling in the width direction may be difficult due to bending of the rolling roll, and conversely, if too thin, the thickness of the polyolefin resin sheet after rolling becomes too thin and uniform rolling. Is not only difficult, but the rolling rolls may come into contact with each other to shorten the life of the rolling roll, so 0.2 to 5.0 mm is desirable.

  The polyolefin resin sheet is first rolled to a rolling ratio of 5 times or more. However, the rolling temperature cannot be uniformly rolled when the temperature is lowered, and melted and cut when the temperature is high. The range of “melting point −40 ° C.” to the melting point of the olefin resin of the polyolefin resin sheet is more preferable, and more preferably “melting point −30 ° C.” to “melting point −5 ° C.” of the olefin resin. The melting point means the maximum point of the endothermic peak accompanying the melting of the crystal, which is recognized when thermal analysis is performed with a differential scanning calorimeter (DSC).

  If the applied pressure (linear pressure) applied to the polyolefin resin sheet by the rolling roll is too small, it may not be possible to obtain a predetermined rolling magnification, and conversely if it is too large, not only will the bending of the rolling roll occur, Sliding easily occurs between the rolling roll and the raw sheet, and uniform rolling may be difficult. Therefore, the applied pressure is preferably 100 MPa to 3000 MPa, and more preferably 300 MPa to 1000 MPa.

  When the rolling ratio is less than 5 times, the effect of suppressing necking at the time of uniaxial stretching performed later cannot be obtained, high-strength uniaxial stretching cannot be performed, or the uniaxial stretching step Therefore, it is 5 times or more, preferably 7 times or more. There is no particular upper limit to the rolling ratio, but the higher the rolling ratio is, the more load is applied to the rolling equipment, so 10 times or less is preferable. The rolling magnification is defined as (cross-sectional area of polyolefin resin sheet) / (cross-sectional area of polyolefin resin sheet after rolling), but the width of the polyolefin resin sheet hardly changes before and after rolling. (Thickness of resin sheet) / (thickness of polyolefin resin sheet after rolling).

  The rolled polyolefin resin sheet is then uniaxially stretched at a total stretch ratio of 10 to 40 times. The uniaxial stretching method is not particularly limited, and the above-described uniaxial stretching method may be adopted. Moreover, since the total draw ratio is 10 to 40 times, the uniaxial draw ratio may be determined so that the total draw ratio is within this range in consideration of the rolling ratio. Is not improved, it is preferably 1.3 times or more, more preferably 1.5 times or more, and still more preferably 1.8 times or more. Moreover, although an upper limit is not specifically limited, 4 times or less are preferable, More preferably, it is 3.5 times or less. The total draw ratio is a value obtained by multiplying the rolling ratio and the uniaxial draw ratio.

  Furthermore, as another preferable stretched polyolefin resin sheet, a stretched polyolefin resin sheet in which a polyolefin resin sheet having a weight average molecular weight of 100,000 to 500,000 is rolled at a rolling ratio of 5 times or more can be mentioned. That is, even if it is not uniaxially stretched only by rolling, it is bent at 180 degrees and 90 degrees in the direction perpendicular to the stretching direction (rolling direction), held for 1 minute, released, and then bent when 5 minutes have passed after release. A stretched polyolefin resin sheet having a shape-retaining property in which both return angles θ are 20 degrees or less can also be suitably used.

  The thickness of the polyolefin-based resin sheet before rolling is not particularly limited, but if it is too thick, stretching becomes difficult, and in the rolling process, a large pressing force is required to crush the polyolefin-based resin sheet with a rolling roll. Take-up force is required, and uniform rolling in the width direction may be difficult due to bending of the rolling roll, and conversely, if too thin, the thickness of the polyolefin resin sheet after rolling becomes too thin and uniform rolling. Is not only difficult, but the rolling rolls may come into contact with each other to shorten the life of the rolling roll, so 0.2 to 5.0 mm is desirable.

  In order to improve the dimensional stability of the stretched polyolefin resin sheet stretched by the stretching method including the rolling step, the stretched polyolefin resin sheet has a melting point of “melting point−60 ° C.” to the melting point of the polyolefin resin, and the rolling temperature. You may anneal at the following temperature.

  If the annealing temperature is lowered, the dimensional stability will not improve, warping will occur if used for a long time, and if it is raised, the polyolefin resin will dissolve and the orientation will disappear and the tensile modulus, tensile strength, etc. will decrease. It is preferable to anneal the resin at a temperature ranging from “melting point −60 ° C.” to the melting point and not higher than the rolling temperature. Other annealing methods are as described above.

  The annealed stretched polyolefin resin sheet may be further aged in the temperature range from 40 ° C. to the melting point of the polyolefin resin. The dimensional stability of the polyolefin resin sheet annealed by aging becomes more excellent.

  Aging is not a continuous treatment in the production line, but it is a relatively long time (minutes, time units) for heat treatment of single-wafers, scrolls, etc., once processed, such as cut winding, of a stretched polyolefin resin sheet. It means to lay down carefully and heat-treat. The aging temperature is the same as that left at room temperature when the temperature is low, and when it is high, it is thermally deformed, so the temperature range is from 40 ° C. to the melting point of the polyolefin resin, and the aging time is not effective in a short time and is too long. Even if an effect does not increase, 12 hours-7 days are preferable.

  If necessary, heat treatment agent, heat resistance improver, light stabilizer, ultraviolet absorber, antioxidant, antistatic agent, impact modifier, antifogging agent, flame retardant, colorant, etc. May be added.

  The stretched polyolefin resin sheet may be a laminated stretched polyolefin resin sheet obtained by laminating two or more of the above stretched polyolefin resin sheets. The stretched directions of the stretched polyolefin resin sheets laminated may be the same or different, but at least one stretched polyolefin resin sheet is stretched in the length direction.

  As a laminated stretched polyolefin resin sheet in which a plurality of stretched polyolefin resin sheets having different stretching directions are laminated, for example, a laminated stretched polyolefin resin in which two stretched polyolefin resin sheets are laminated so that the stretching directions are orthogonal to each other Sheet, laminated stretched polyolefin resin sheet in which three stretched polyolefin resin sheets are laminated by shifting the stretching direction by 60 degrees, and laminate in which four stretched polyolefin resin sheets are laminated by shifting the stretching direction by 45 degrees Examples thereof include a stretched polyolefin resin sheet.

  The stretched polyolefin-based resin sheet has shape retention when bent in a direction perpendicular to the stretching direction, and when two or more stretched polyolefin-based resin sheets having different stretching directions are bonded, two or more stretched polyolefins The shape-retaining property in an arbitrary direction is improved by the stretching direction of the resin-based resin sheet, and the stretched polyolefin-based resin sheet is hardly broken even if the stretching direction and the bending direction of the stretched polyolefin-based resin sheet are the same.

  The method of laminating the stretched polyolefin resin sheet may be any conventionally known method, for example, a method in which the second polyolefin resin sheet is supplied between the stretched polyolefin resin sheets and thermally bonded, Examples thereof include a method in which a second polyolefin resin is melt-extruded and bonded and laminated between stretched polyolefin resin sheets.

  As the second polyolefin resin, since the stretched polyolefin resin sheet is adhered, the same type of polyolefin resin as that constituting the stretched polyolefin resin sheet is preferable. Since it acts as an adhesive when heat-sealing, a polyolefin resin having a melting temperature lower than the melting temperature of the polyolefin resin constituting the stretched polyolefin resin sheet is preferable, and a linear low density polyethylene resin is preferable.

  The thickness of the second polyolefin resin (sheet) is not particularly limited. However, if the thickness is too thin, it is difficult to adhere, and if it is too thick, the shape-retaining property of the stretched polyolefin resin sheet is lowered. It is -150 micrometers, Preferably it is 20-80 micrometers.

  The laminated stretched polyolefin resin sheet is also bent at 180 degrees and 90 degrees so as to be perpendicular to the stretching direction of at least one stretched polyolefin resin sheet of the laminated stretched polyolefin resin sheets. It is released after being held for a minute, and has a shape-retaining property in which the folding return angle θ is 5 degrees or less when 5 minutes have passed after the release.

  The thickness of the stretched polyolefin resin sheet is not particularly limited, but is preferably 0.04 to 2 mm because the shape retainability decreases as the thickness decreases. Since the laminated stretched polyolefin resin sheet laminates the above stretched polyolefin resin sheet, it is possible to produce a thick sheet. However, if it is too thick, it becomes difficult to bend and the shape retainability is lowered, so 0.08 to 4.0 mm is preferable. . Moreover, it is preferable that at least one layer in the laminated stretched polyolefin resin sheet is stretched in the length direction.

  The width of the stretched polyolefin-based resin sheet is not particularly limited, but is preferably 0.5 to 10 mm because the shape retainability decreases when the width is narrowed.

  The stretched polyolefin resin rod may be produced by uniaxial stretching or rolling in the same manner as in the production of the polyolefin resin sheet described above, but the polyolefin resin rod is uniaxially stretched or rolled to have an appropriate thickness. Since it is difficult to obtain a rod having retainability, it is preferable to produce a stretched polyolefin resin rod having the shape retainability described above, and cutting or cutting out the stretched polyolefin resin rod.

  The thickness of the stretched polyolefin resin rod is not particularly limited, but it is preferably 0.5 to 3.0 mm because the shape retainability decreases as it becomes thinner. The cross-sectional shape is not particularly limited, and examples thereof include a circle, an ellipse, a quadrangle, a hexagon, an octagon, and a dodecagon. Furthermore, a thick stretched polyolefin resin rod may be formed by bundling or twisting the stretched polyolefin resin rod.

  The number of the shape retaining material 5 laminated on the packaging bag main body 1 is not particularly limited, and may be appropriately determined from the required shape retaining property and appearance, but is generally about 1 to 5. Further, the length of the shape-retaining material 5 is not particularly limited, but generally, 1 to 3 cm of the unsealed portion 4 is left (from the position of 1 to 3 cm from the upper end of the packaging bag body 1). It is preferable that the length is 2 to 2/3.

  The method of laminating the shape-retaining material 5 on the packaging bag body 1 is not particularly limited, and examples thereof include a method of laminating an adhesive layer on one surface of the shape-retaining material 5 and / or the packaging bag body 1 and bonding them. The adhesive is not particularly limited as long as it is an adhesive capable of adhering the shape-retaining material 5 to the packaging bag body 1. For example, a hot-melt adhesive such as a polyester or polyolefin, a reactive adhesive, an epoxy Adhesives such as system adhesives, urethane adhesives, polyester adhesives, and rubber-based, acrylic-based, urethane-based, and silicon-based adhesives. The thickness of the adhesive layer is generally 5 to 50 μm. Moreover, when the packaging bag main body 1 consists of laminated | multilayer film, you may interpose the shape retention material 5 between the laminated | stacked films.

  In order to fill the packaging bag of the present invention with the contents, the unsealed portion 4 may be opened, and after filling the packaging bag main body 1 with the contents from the unsealed portion 4, the unsealed portion 4 may be bonded. In order to take out the contents from the packaging bag, the bonded unsealed portion 4 may be cut with a scissors or the like, and the contents may be taken out from the opened unsealed portion 4. In order to reseal the packaging bag with the contents remaining, the packaging bag body 1 may be folded together with the shape retaining material 5 in the length direction of the shape retaining material 5. When the shape retaining material 5 is folded, the shape retaining material 5 is retained in the folded shape, so that the packaging bag is resealed and retained in that state. To take out the contents from the packaging bag again, the packaging bag body 1 and the shape-retaining material 5 may be folded back to the original shape by hand and the contents taken out from the opening, and then the packaging bag body 1 and the shape-retaining material again. If 5 is folded as described above, the packaging bag can be resealed again.

  Next, examples of the present invention will be described, but the present invention is not limited to the examples.

Example 1
A high-density polyethylene resin (manufactured by Nippon Polyethylene Co., Ltd.) having a weight average molecular weight (Mw) of 330,000 and a melting point of 135 ° C. is supplied to the same-direction biaxial kneading extruder (manufactured by Plastic Engineering Laboratory) and melt kneaded at a resin temperature of 200 ° C. After that, the melt-kneaded material was formed into a sheet having a width of 370 mm and a thickness of 4.0 mm by a calender molding machine in which the roll temperature was controlled at 110 ° C. to obtain a polyethylene resin sheet.

  The obtained polyethylene resin sheet was rolled to a rolling magnification of 9.0 times using a rolling molding machine (manufactured by Sekisui Koki Co., Ltd.) heated to 125 ° C. to obtain a rolled polyethylene resin sheet having a thickness of 0.50 mm. The obtained rolled polyethylene resin sheet was subjected to a multistage stretching of 1.82 times in a hot air heating type multistage stretching apparatus (manufactured by Kyowa Engineering) heated to 110 ° C., a total stretching ratio of 16 times, a width of 280 mm, and a thickness of 0 A 34 mm stretched polyethylene resin sheet was obtained.

  The obtained stretched polyethylene resin sheet was supplied with a pinch roll to a hot air heating tank with a line length of 19.25 m set at 125 ° C. at an inlet speed of 2.75 m / min, and an outlet speed of 2.75 m / min. Set to, and then subjected to primary annealing for 7 minutes, followed by secondary annealing in the same manner to obtain an annealed stretched polyethylene resin sheet, which is then fed to a constant temperature bath at 60 ° C. and aged for 24 hours, An aged stretched polyethylene resin sheet was obtained.

  The obtained stretched polyethylene resin sheet was cut into a width of 10 mm and a length of 15 cm so that the length direction was the stretch direction, and bent at 180 degrees and 90 degrees so as to be orthogonal to the stretch direction of the stretched polyethylene resin sheet. It was released after being held for 1 minute, and when the bending return angle θ was measured after 5 minutes had elapsed from the release, it was 4 ° to 7 °.

  The obtained stretched polyethylene resin sheet is cut into a width of 5 mm and a length of 120 mm so that the length direction is the stretch direction to obtain a shape-retaining material 5, and an acrylic pressure-sensitive adhesive layer having a thickness of 20 μm is laminated on one surface thereof. did.

  A linear low-density polyethylene was melt-coated to a thickness of 60 μm on one surface of a biaxially stretched polyester film having a height of 200 mm, a width of 210 mm, and a thickness of 12 μm to obtain a film material. As shown in FIG. 1, the obtained film material is folded so that the linear low-density polyethylene layer is on the inside, laminated so that the ends overlap each other by 5 mm, and heat-sealed to form a palm seal part 2 and the bottom part was heat-sealed with a width of 5 mm to form a bottom seal part 3, and a packaging bag body 1 having a height of 200 mm and a width of 100 mm having an unsealed part 4 on the upper side was obtained. Between the position of 15 mm from the upper side of the packaging bag body 1 so that the shape-retaining material 5 is substantially perpendicular to the unsealed portion 4 so that the acrylic adhesive layer is in contact with the obtained packaging bag body 1. The packaging bag of the present invention was obtained by sticking to the above.

  The obtained packaging bag was filled with 200 g of snack confectionery, and the unsealed portion 4 was heat-sealed with a width of 5 mm, whereby the snack confection could be sealed in the packaging bag. Next, the heat-sealed unsealed part 4 was cut with scissors, and after taking out 100 g of the contents, it was folded three times with a 15 mm width from the upper side to the lower side, and then left to stand and folded. The packaging bag was resealable in the state. Furthermore, the folded portion could be easily folded back by hand and returned to its original state, and the contents could be taken out.

  The packaging bag of the present invention is easy to manufacture and inexpensive, and can be used again in the packaging field because it can be easily resealed simply by folding after opening.

DESCRIPTION OF SYMBOLS 1 Packaging bag main body 2 Joint seal part 3 Bottom seal part 4 Unseal part 5 Shape maintenance material

Claims (1)

  A packaging bag body having an unsealed portion on one side is laminated with a sheet-shaped or rod-shaped shape retaining material in a direction substantially perpendicular to the unsealed portion, and the shape retaining material is a stretched polyolefin resin sheet or rod The shape is retained at a bending angle of 180 degrees or 90 degrees in a direction substantially perpendicular to the length direction and held for 1 minute and then released, and the folding return angle θ is less than 20 degrees when 5 minutes have passed after the release. A packaging bag comprising:

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