JP2006123927A - Easily unsealable packaging bag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily unsealable packaging bag in which even a breakable content can be easily and reliably unsealed, the content and a film can be easily separated from each other even in a gusset type package with the content such as sweet jellied bean-paste being tightly attached to the film, an unsealing end can be easily opened, and any trouble hardly occurs during the unsealing. <P>SOLUTION: A substantially axis-symmetric packaging bag is constituted of a laminate film consisting of a base layer and a heat-bonding resin layer with the heat-bonding resin layer inside. One end in the axial direction is sealed, and the laminate film has a straight cutting property in the direction substantially parallel to the axial direction. The end comprises a substantially trapezoidal unsealing tab part and an easily unsealable and sealed heat-bonded part. The heat-bonded part has at least one shape to be converged in an inverted V-shape toward the end. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a packaging bag made of a plastic film and having an easy-opening property that allows a package to be easily opened with fingers.

  A plastic package is used as a typical packaging material, and the package is sealed with the contents stored in a packaging bag. The contents are contained in a bag-shaped product made of packaging materials according to the shape and size of the contents. The both ends of the cylindrical object are housed and hermetically sealed.

  Such packaging bags are known in various shapes, but it is troublesome to use a tool such as scissors when opening. However, when the film is cut with fingers, the contents may fall down due to the reaction of the cut. In addition, if the contents are fragile confectionery such as castella, or if it is a whole package of processed marine products, the contents may be damaged when opened, Sometimes it was difficult to remove from the packaging bag.

  In particular, the gusset-type packaging bag is a packaging bag that can be beautifully packaged in accordance with the shape of a three-dimensional content such as a box or Japanese confectionery, but it is relatively difficult to open the package, and the folding seal part is It tends to become resistance when opening. Therefore, the part between the fold seal part and the contents is cut using a tool such as scissors, or the fold seal part is cut and the film is torn from the cut with fingers. It was normal.

  However, in the case of a gelled material that has been cooled and solidified after filling the packaging bag with a fluid such as sheep, the film and the contents are in close contact with each other. It sometimes took time to separate the contents. The same thing has been pointed out, as in Castella, in which an oxygen absorbent is enclosed together during filling, so that the inside of the package is depressurized and the packaging bag and the contents are in close contact with each other. Therefore, there has been a demand for a gusset-type packaging bag that can maintain the sealed state of the contents in the package, can be easily opened with fingers, and can be easily separated from the contents and the packaging bag.

  As an easy-opening technique related to a packaging bag, a bag-like container having a gusset fold portion folded in a V shape on both left and right sides of a cylindrical film provided with a vertical seal portion, and at least a quadrilateral by filling with the contents In a gusset bag-like container in which a cylindrical side portion and a flat rectangular bottom portion are formed, an unsealed portion is provided in a partial region on the film outer end side of the vertical seal portion, and the upper film outer end of the unsealed portion Patent Document 1 discloses a gusset-type packaging bag in which an opening for cutting in a direction orthogonal to a vertical seal portion is cut at an edge. However, since the direction in which the film is torn and the level of force required for tearing is unstable, the contents may fall down or be damaged due to unexpected opening. Furthermore, the problem of the adhesion between the packaging bag and the contents has not been solved.

In addition, as an easy-open packaging bag that can be easily opened and removed smoothly from the packaging bag without losing the shape of the contents, a laminated film composed of a linear cut film and a heat-fusible film is thermally fused. It is a packaging bag having a back-pasted part that is made by making a bag, wherein at least one heat-sealed part has a non-adhesive part between the film edge and the heat-fused part is easily peelable. Patent Document 2 discloses an easy-open packaging bag characterized in that both corners of the non-adhesive portion are cut and at least one surface of the packaging bag is opened from the non-adhesive portion along a fold line. Has been. In this packaging bag, once the opening end is opened, the subsequent opening easily proceeds. However, in order to open the opening end first, a certain force must be applied to the fingers. For this reason, after opening the opening end by applying force, the entire opening opens as soon as resistance is small, and the contents are more likely to fall down.
JP 2002-104439 A JP 2004-26169 A

  The present invention is capable of easily and reliably opening a fragile item or a large item such as a single piece, and in particular, a gazette in which the content and the film are in close contact like a sheep or castella. It is an object of the present invention to provide an easy-open packaging bag in which the contents and the film can be easily separated from each other in the mold package, and the opening end is easy to open, and troubles during opening are unlikely to occur.

  1st of this invention is a substantially axisymmetric packaging bag comprised using the laminated | multilayer film which has a base material layer and a thermoadhesive resin layer, and the said thermoadhesive resin layer inside, Comprising: The said axial direction One end of the laminated film is hermetically sealed, the laminated film has a straight-cut property in a direction substantially parallel to the axial direction, and the end is hermetically sealed with a substantially trapezoidal opening picking portion. A heat-bonding portion, and the heat-bonding portion has at least one shape that converges in an inverted V shape toward the end portion.

  A second aspect of the invention is a side surface having a deformed hexagonal cylindrical shape in which a laminated film having a base material layer and a thermal adhesive resin layer is used, and two opposite sides are folded inward with the thermal adhesive resin layer inside. And a gusset-type packaging bag in which one end in the axial direction of the deformed hexagonal cylinder is sealed, and the laminated film has a linear cut property in a direction substantially parallel to the axial direction, and the end is , Having a substantially trapezoidal opening picking portion and a heat bonding portion sealed with easy opening, and the heat bonding portion has a shape converging in an inverted V shape from the side surface portion toward the end portion. It is a packaging bag characterized by having at least one.

  Here, it is preferable that the adhesive strength of the thermal bonding portion is 2N / 15 mm width or more and 20 N / 15 mm width or less. The thermal adhesive resin layer comprises a layer (A) mainly composed of a high melting point resin having a melting point of 135 ° C. or more and 180 ° C. or less, a low melting point resin having a melting point of 80 ° C. or more and less than 135 ° C., and the high melting point And a layer (B) mainly composed of a mixed resin with a resin, the difference between the melting point of the high melting point resin and the highest melting point of the low melting point resin being 20 ° C. or more, and the two layers However, it is preferable to laminate | stack in order of (B) (A) from the heat bonding surface of the said heat bondable resin layer.

  A third aspect of the invention is a substantially axisymmetric package in which a laminated film having a base material layer and a heat-adhesive resin layer is used, and the packaged object is packaged with the heat-adhesive resin layer inside. And both end portions in the axial direction are sealed, and the laminated film has a linear cut property in a direction substantially parallel to the axial direction, and at least one of the end portions has a substantially trapezoidal shape. And a heat-bonding portion sealed with easy opening, and the heat-bonding portion has at least one shape converging in an inverted V shape toward the end portion. It is a packaging body.

  It was possible to easily and reliably open the contents even if the contents were fragile or a single piece without damaging the contents. Even in gusset-type packagings such as yokan and castella where the contents and the film are in close contact, it is easy to separate the contents and the film, and it is easy to open the open end, which is the same as the subsequent opening. The power of Therefore, troubles at the time of opening are unlikely to occur.

  Embodiments of the present invention will be specifically described with reference to the drawings. Here, a gusset type packaging bag will be first described as an example. FIG. 1 is a schematic diagram showing a schematic configuration of a gusset type packaging bag. 1 (a) is a front view of the packaging bag 1, FIG. 1 (b) is a right side view of the same packaging bag 1, and FIG. 1 (c) is an illustration of the end 4 of the unsealed packaging bag 1. FIG. It is the perspective view seen from the direction. In FIG. 1, the heat-bonded portion or the portion after peeling off from the heat-bonded portion is indicated by hatching. The same applies to FIGS.

  The packaging bag 1 includes a side part 3 that forms a cylindrical space when the contents are stored, and end parts 2 and 4 that are positioned at both ends of the cylinder of the side part 3 in the axial direction and are sealed by thermal bonding. Consists of. In the example shown in FIG. 1 (a), one end 2 is thermally bonded and sealed, while the other end 4 remains open to fill the contents. After the end 4 is filled with the contents, it is thermally bonded and sealed. The side surface portion 3 constitutes a hexagonal cylinder composed of six side surfaces 10 to 15 sequentially connected to each other at six sides 33 to 38 substantially parallel to the axial direction, and two opposite sides 35 of these six sides. , 36 is used as a crease, and the side surfaces 12 to 15 have a deformed hexagonal cylinder shape that is folded inside the hexagonal cylinder. Here, the axial direction means a direction parallel to the axis of symmetry of the packaging bag 1 that is generally symmetrical about the axis, as indicated by the arrow in FIG.

  Until the contents are filled, the packaging bag is stored in a state where the side portions 12 to 15 including the folds 35 and 36 are folded. When the contents are filled from the opening on the end 4 side, the folded state between the side surfaces 12 and 13 and the side surfaces 14 and 15 disappears, and each returns to one plane. Thus, the side surface portion 3 is deformed from a substantially hexagonal cylinder shape to a substantially square tube shape. The contents are filled inside the rectangular tube shape. Such a packaging bag is called a gusset type packaging bag.

  In the example shown in FIG. 1, the six side surfaces 10 to 15 constituting the side surface portion 3 are composed of one film, and are not shown provided along the symmetry axis of the side surface 11. It is processed into a cylindrical shape by a backrest. Such a packaging bag 1 uses a laminated film having a base material layer and a heat-adhesive resin layer, and the heat-adhesive resin layer is on the inside of the packaging bag so as to be cut, folded, heat-bonded or the like. Create by processing.

  The laminated film used for the packaging bag 1 has a unidirectional linear cut property. The unidirectional linear cut property means a property that literally easily tears linearly in one direction, and the packaging bag 1 uses a film so as to be easily teared linearly along the axial direction. By doing in this way, when the opening knob is pulled and the package is opened, the laminated film can be cleanly cut in the intended direction without unexpected cutting.

  Unidirectional straight-cut property refers to a property defined by the following measurement method. The film is cut into a square of 520 mm square along the direction perpendicular to the flow direction and the flow direction during the production of the laminated film. As shown in FIG. 2, two notches are formed at intervals of 30 mm at the edge of the cut piece perpendicular to the direction in which the straight cut property is tested. The film is torn in a direction parallel to the straight cut direction by grasping a 30 mm cut with a finger (the film is cut as shown by a dotted line in FIG. 2).

  In general, depending on the orientation direction of the molecules and the orientation direction of the blended components of the resin, the degree of film breakage may vary depending on the tear direction of the film. The straight-cut property is determined based on the width of the leading end “X” of the film on which the leading end of the tear becomes narrower. A film whose value of X is less than 5 mm or does not reach the edge where tearing is opposed is referred to as a film having no linear cut property, and a film having a value of 5 mm or more is referred to as a linear cut film. Details of the laminated film having such properties will be described later.

  In the packaging bag 1, one end portion 2 that is sealed in advance is a portion that becomes a starting point of opening when the packaging body in which the contents are sealed in the packaging bag 1 is opened with fingers. The end portion 2 includes substantially trapezoidal opening knobs 20 and 21 and heat-bonding portions 51 and 52 that are easily opened and sealed in advance by thermal bonding. The opening knobs 20 and 21 are not adhered to each other, and the package can be opened by picking them with fingers and peeling them in the opposite direction.

  The opening knobs 20 and 21 are substantially isosceles trapezoidal shapes with the tip 30 of the end 2 as the upper base, the boundary between the side surface 3 and the end 2 as the lower bottom, and the edges 31 and 32 as legs. I am doing. Since the opening knobs 20 and 21 have a width that decreases toward the tip of the end 2, that is, the upper base is shorter than the lower base, both the end sides 31 and 32 are side portions. It is a straight line that is inclined in the direction of the axis of symmetry with an acute angle R1 from the ten side edges 33, 34. Since the end sides 31 and 32 form an acute angle R1 in this way, the connecting portion between the end sides 31 and 32 and the end sides 33 and 34 acts as a kind of cut, and the opening force is smoothly applied to the end sides. It is transmitted from 31 and 32 to the end sides 33 and 34, and opening becomes easy.

  As shown in FIG. 1A, the opening knobs 20 and 21 have a width of 5 mm or more at the tip perpendicular to the axial direction and a length of 5 mm or more along the axial direction from the intersection 50. It is preferable that the width is 7 mm or more and the length is 7 mm or more, and more preferably the width is 10 mm or more and the length is 10 mm or more. The upper limit of the width is preferably shorter than the width of the side surface part 3 by 5 mm or more, more preferably 1 cm or more. The upper limit of the length is not particularly defined, but it is natural that the size of the packaging bag is not exceeded, and if it is too large, useless material is used. In any case, it may be a common sense size suitable for opening with fingers.

  The heat bonding portions 51 and 52 (53 and 54 on the back surface) of the end portion 2 are belt-shaped and reach from the end side 33 to the end side 34 so that the package can be kept sealed when the package is formed. Is pre-heat bonded. As shown in FIG. 1A, the thermal bonding portions 51 and 52 are oblique lines that form an acute angle R2 that is larger than the acute angle R1 with respect to the edges 33 and 34 of the side surface portion 3, and end from the side surface portion 3 to the end portion. It converges toward 2 and has an inverted V shape with the vertex at the intersection 50. Thus, by making it an inverted V shape, the force applied in the case of opening can be utilized efficiently. That is, if the knob is peeled off at the time of opening, the force applied for opening is concentrated at the intersection 50 of the heat bonding portion. Therefore, opening can be started with a relatively small tearing force. In addition, the force applied after the start of opening can be used effectively for opening.

  Here, the range of the acute angle R2 is preferably 30 ° or more and 80 ° or less, more preferably 40 ° or more and 70 ° or less, and further preferably 45 ° or more and 60 ° or less. Within this range, opening is easy, and waste is hardly generated in the packaging bag material. Moreover, it is preferable that the seal widths of the thermal bonding portions 50 to 53 are 2 mm or more and 20 mm or less, respectively, more preferably 3 mm or more and 15 mm or less, and further preferably 3 mm or more and 10 mm or less. This makes it easier to achieve easy opening while maintaining the necessary sealing properties.

  Moreover, the heat bonding part has an adhesive strength within a range of easy opening so that it can be easily opened by fingers. Specifically, the adhesive strength is preferably 2 N / 15 mm width or more and 20 N / 15 mm width or less. When the adhesive strength is 2N / 15 mm width or more, the strength required for a packaging bag can be ensured, and bag breakage is less likely to occur when filling the contents, during transportation after packaging, or during storage. Further, the adhesive strength is 20 N / 15 mm width or less, and it becomes possible to peel off the heat-bonded portion with the finger when opening. A more preferable range of the adhesive strength is 2 N / 15 mm width or more and 17 N / 15 mm width or less, and more preferably 3 N / 15 mm width or more and 15 N / 15 mm width or less.

  On the other hand, in the end 4 which is the end opposite to the end 2 used for opening, the thermal bonding portion provided after filling the contents does not need to be peeled off at the time of opening. However, it may be peeled off. Therefore, the adhesive strength of the thermal bonding portion at the end portion 4 may be within the range of easy opening or may be stronger. If the adhesive strength of this part is 20 N / 15 mm width or more, a seal part that does not need to be peeled off at the time of opening is difficult to peel off, which is preferable. By using a heat-adhesive resin layer that can selectively use two heat-bonding strengths, which will be described later, it is possible to easily and reliably achieve different bond strengths depending on the location.

  Next, the packaging body 5 in which the packaging bag is filled with contents from the opening of the end 4 and then the opening of the end 4 is sealed will be described. In addition, what is necessary is just to carry out the filling of the content similarly to a normal gusset type packaging bag. A perspective view of the package 5 is shown in FIG. In the package 5, the side surfaces 14 and 15 in the side surface portion 3 of the packaging bag are returned to one plane with the end side 36 that has been folded inwardly extended. For this reason, the deformed hexagonal cylinder is transformed into a square cylinder.

  The end part 2 which becomes the opening end of the package 5 is overlapped in a state where the substantially trapezoidal surfaces 20 and 21 are not bonded to each other, and constitutes an opening picking part which can be picked with fingers. The end portion 2 is sealed by inverted V-shaped thermal bonding portions 51 and 52 that are provided at the stage of the packaging bag and have an intersection 50 at the apex.

  The other end 4 of the package 5 is sealed with a band-shaped thermal bonding portion 70 provided in a direction perpendicular to the axial direction by folding the film into a normal shape. The end 4 may be sealed by a conventionally known method. For example, the end 4 may be formed into a quadrangle by folding the film diagonally and thermally bonding. Moreover, it is good also as an opening end similarly to the edge part 2 depending on the case.

  When opening the package 5, the opening knob 20 or 21 is picked with fingers and peeled off from the package 5. A method of applying force when the knob portion 20 is picked and peeled off from the package 5 will be described with reference to FIG. FIG. 4 is a schematic view showing a direction of the force by enlarging a part around the intersection 50 of the easily-openable thermal bonding portions 51 and 52. The peeling force F first concentrates on the inverted V-shaped intersection 50. For this reason, the easy-opening intersection 50 is originally opened easily and becomes an opening end. When the thermal bonding portion is peeled off at the intersection 50, the peeling force F is applied to the thermal bonding portions 51 and 52 that are inclined with respect to the force F as forces f1 and f2, respectively. At this time, since the thermal bonding portions 51 and 52 are respectively inclined with respect to the peeling direction, the forces f1 and f2 are applied to the respective thermal bonding portions without greatly decreasing from the force F, and then easily pulled. Peeling can be performed.

  When the heat-bonded portions 51 and 52 are peeled off, the peeling force is applied to the end sides 33 and 34, and the lower end of the trapezoidal legs of the end portion 2 is started as a starting point. The film is torn along the one-way linear cut direction. Thus, the schematic diagram of the state in the middle of opening a package is shown in FIG. The opening knob 20 and the side surface 10 continuous therewith are torn along the end sides 33 and 34, and the contents 6 are exposed. What is necessary is just to take out the content 6 when the side surface 10 is fully opened. In FIG. 5, the hatched portions 60 and 61 are shown after the thermal bonding portions 51 and 52 are peeled off.

  Thus, since the opening force F concentrates on the easy-opening intersection 50 at the beginning of opening, the opening is smoothly started. Moreover, since the thermal bonding portions 51 and 52 are oblique to the opening force F even after the opening is started, the opening is continued smoothly. When the thermal bonding portions 51 and 52 are all opened, the side surface 10 is smoothly cut out along the edges 33 and 34 according to the unidirectional cut property. As a result, the bag can be opened easily even though it is a gusset type packaging bag, and it is not necessary to apply a strong force particularly at the start of opening, and the force required for opening from the beginning to the end of the opening becomes relatively uniform. Therefore, it can be opened stably, and the trouble that the contents fall down with opening is not generated.

  In addition, since the contents and printing do not become difficult to see, the display effect is also excellent. Furthermore, even if the contents are fragile like a short cake, they can be easily opened without breaking the contents. Furthermore, the film and the contents can be easily separated even in a package body in which the contents and the film are in close contact, such as canola and castella.

  Next, FIG. 6 is a view showing an example of a pillow type packaging bag. 6A is a front view and FIG. 6B is a perspective view. A trapezoidal opening knob 80 having two diagonal lines 81 inclined at an acute angle R1 with respect to the axial direction as a leg, and heat converging in an inverted V shape from the side surface storing contents to the end. The structure of the bonding portion 82 is the same as that of the gusset type packaging bag 1. Similarly, after the contents are filled from the opening of the lower end 83, the lower end 83 is heat-sealed and sealed.

  Next, FIG. 7 is a view showing another example of a pillow-type packaging bag. FIG. 7A is a front view, and FIG. 7B is a perspective view. In this example, there is a difference in that the thermal bonding portion 92 is configured by arranging two inverted V-shapes in a direction substantially perpendicular to the axial direction instead of one inverted V-shape. Even if it does in this way, at the time of opening, since either of the inverted V-shaped vertices becomes an opening end, the package can be easily opened as in the case of one inverted V-shaped. Furthermore, by doing in this way, the length of the axial direction required in order to provide the heat bonding part 92 becomes short, and it becomes possible to make a packaging bag more compact.

  As described above, the number of the inverted V shapes arranged is not limited to one or two, and three or more may be arranged so as to be substantially perpendicular to the axial direction. Further, when arranging a plurality, the whole may be equally arranged in a single line, or the inverted V-shaped apex located near the center in the direction substantially perpendicular to the axial direction is positioned closer to the end, Inverted V-shaped apexes located near both ends in a substantially perpendicular direction may be positioned farther from the end. By doing so, the force concentrates on the inverted V-shape located near the center at the time of opening, so that the opening becomes easy and the packaging bag can be made compact.

  Next, a laminated film suitable for manufacturing such a packaging bag or package will be described. The laminated film is constituted by laminating at least a base material layer and a thermoplastic resin layer. It is preferable to give the base layer a characteristic that is a linear cut property of the laminated film, and to give a heat-adhesive resin layer a property that is easy to open.

  A base material layer consists of a film which has a unidirectional linear cut property. Examples of the film having a unidirectional linear cut property include a longitudinally uniaxially or laterally uniaxially stretched polyolefin resin film such as a uniaxially stretched polyethylene film and a uniaxially stretched polypropylene film, and nylon 6 as described in, for example, JP-A-7-113015. A biaxially stretched polyamide-based resin film in which a polymetaxylylene adipamide resin is mixed with a resin to devise a layer separation structure and stretching conditions, or a polyethylene terephthalate resin, for example, as described in JP-A-11-300916 Examples thereof include a biaxially stretched polyester resin film in which a polybutylene terephthalate resin is mixed to devise a layer separation structure and stretching conditions. As another method for imparting unidirectional linear cut property, for example, two films having different molecular orientation of films described in JP-A-9-156649 are laminated back to back, that is, two films. A combination of film layers may be used so that a pair of the films exhibits a straight cut property.

  The base material layer can be constituted by laminating other films within a range that does not impair the unidirectional linear cut property. For example, in order to increase the strength of a film, generally, a stretched film made of polypropylene (hereinafter referred to as PP) (hereinafter referred to as OPP), a stretched film made of nylon resin (hereinafter referred to as Ny) (hereinafter referred to as ONy), a stretched film made of polyethylene terephthalate (hereinafter referred to as PET) (hereinafter referred to as PET). Film) and the like are preferably used.

  Further, as a function other than strength, for example, to provide gas barrier property, particularly oxygen barrier property, for example, polyvinylidene chloride (hereinafter referred to as PVDC), polyvinyl alcohol (hereinafter referred to as PVA), PVA on the surface of the OPP, ONy, and PET film. A film in which a layer having a barrier property such as organosiloxane mixed with flaky inorganic material is coated can be used. Further, a film obtained by laminating and stretching PP and ethylene-vinyl alcohol copolymer resin (hereinafter EVOH) instead of OPP, or a film obtained by laminating and stretching Ny and metaxylene adipamide resin instead of ONy, A film obtained by laminating and stretching Ny and EVOH can be used. Moreover, the film etc. which vapor-deposited aluminum, aluminum oxide, silicon oxide etc. on the surface of the said OPP, ONy, and PET film can be used. Furthermore, a film having gas barrier properties such as a PVDC film, an EVOH film, an aluminum foil, or the like can be laminated on the OPP, ONy, or PET film.

  The heat-adhesive resin layers of the laminated film can be heat-bonded to each other and need to be heat-bondable at least for easy opening. In order to make it easy to open, first, there is a method of using an easily peelable film for the heat-adhesive resin layer. Examples of such a film include TAF-650C manufactured by Tosero Co., Ltd. and SMX-Y03 manufactured by J Film Co., Ltd., which weaken the strength of the resin layer and causes cohesive failure during peeling, and DIFAREN-E3700T manufactured by Dainippon Ink and Chemicals As described above, the laminate structure may be one in which the interlayer adhesive strength is weakened and the layers are peeled at the time of peeling.

  Moreover, as described in Japanese Patent Application No. 2003-360140, the heat-adhesive resin layer has a layer (A) mainly composed of a high melting point resin having a melting point of 135 ° C. to 180 ° C., and a melting point of 80 ° C. A layer (B) mainly composed of a mixed resin of a low melting point resin and a high melting point resin having a temperature of ˜135 ° C., the melting point of the high melting point resin of the layer (A) and the highest melting point of the low melting point resin of the layer (B) It is preferable to use a film in which the difference is 20 ° C. or more and the layers (B) and (A) are laminated in this order from the thermal bonding surface. In this case, the layer (A) side is used as the base material layer, and the layer (B) side is used as the heat bonding surface side. Or you may make it produce the film of the layer structure of (B) (A) (B), and to laminate | stack this with a base material layer.

  If it does in this way, if a heat bonding temperature is made lower than melting | fusing point of high melting point resin, an adhesion mirror will become weak and it will become easy-open property, and if it raises, adhesive strength will become strong and it will become difficult to open. The bond strength jumps across the threshold temperature, and the bond strength remains constant in any bonding temperature region, even if the bonding temperature varies slightly within that region. That is, two different levels of adhesive strength can be reliably used for easy opening and difficult opening.

  In this case, the thermal bonding layer further includes a layer (A) mainly composed of a high melting point resin, a layer (B) mainly composed of a mixed resin of a low melting point resin and a high melting point resin, and a layer mainly composed of a low melting point resin (C It is more preferable that at least three layers of) are laminated. In this case, the layer (A) mainly composed of the high melting point resin is used as the base layer side, and the layer (C) mainly composed of the low melting point resin is used as the heat bonding surface side. Or you may make it produce the film of the layer structure of (C) (B) (A) (B) (C), and to laminate | stack this with a base material layer.

  As described above, there are various methods for obtaining easy-openability, and the method may be appropriately selected according to the purpose and contents of the packaging bag. The packaging bag can be printed on the above-described unidirectional straight-cut film or other film in order to demand purchase motivation or to display information on the contents.

  A method for obtaining a laminated film by laminating the plurality of films is not particularly limited, and a known technique can be used. For example, a dry lamination method in which an adhesive is applied to the film surface and bonded together, an extrusion lamination method in which a molten resin is extruded between two films to form an intervening layer, and the like can be used.

  In the production of the packaging bag, it may be produced in the same manner as in the production of a normal packaging bag so that the heat-adhesive resin layer is inside the packaging bag. The part different from the manufacturing process of a normal packaging bag requires that the end 2 be cut into a substantially trapezoidal shape, and that the heat seal bar for performing the heat bonding parts 51 and 52 has a specific shape. It is necessary to prevent the positional relationship between the heat seal bar and the film from deviating when the packaging bag is heat sealed to form the heat bonding portions 51 and 52.

  For example, the manufacturing process of a gusset type packaging bag may be as follows. A laminated film is prepared in advance by laminating a film for a base material layer having a straight cut property in the longitudinal direction and a film for an easily-openable heat-adhesive layer by dry lamination. In the bag making process, a laminar film is rolled in the longitudinal direction and rolled up into a cylindrical shape to make a backrest. Next, with the backrest in the center, both sides are folded inward and folded into a deformed hexagonal cylinder. Next, the heat bonding portions 51 and 52 are formed at regular intervals using a heat seal bar. Finally, in the vicinity of the thermal bonding portions 51 and 52, the hexagonal cylinder is cut at regular intervals, and both sides of the end portion 2 are cut obliquely so that the end portion 2 has a substantially trapezoidal shape. Thus, the packaging bag 1 is completed. Other shape bags can be manufactured in the same manner.

  In addition, in the case of reverse V-shaped heat bonding, the heat seal bar has a unique shape, so if the meandering of the film occurs, the position of the heat bonding portions 51, 52 relative to the packaging bag will be shifted, Due to the relationship with the step of cutting the substantially trapezoidal shape in the subsequent step, a part of the thermal bonding portions 51 and 52 is cut and the end portion 2 cannot be sealed. In order to prevent this, it is preferable to install a sufficient number of jigs for suppressing meandering at relatively narrow intervals so that the film does not meander before the thermal bonding treatment. The same applies to the cutting process of Mimi.

  As a form of the packaging bag, a gusset type packaging bag is most suitable, but it is not limited to a gusset type, and may be a pillow packaging bag or other forms of packaging bags. Further, the reverse V-shaped thermal bonding portion is not limited to one having only one reverse V-shape, and may be a form in which a plurality of reverse V-shapes are arranged in a direction perpendicular to the axis of the packaging bag. Even in this way, at the time of opening, the opening starts from one of the inverted V-shaped vertices, and the same effect as in the case of only one can be obtained. Further, by arranging a plurality of inverted V shapes, one inverted V shape is reduced, so that there is an advantage that the axial width of the thermal bonding portion can be shortened.

  Hereinafter, the present invention will be described based on examples. The thermal bond strength was evaluated as follows. First of all, the test pieces were joined to the heat bonding surfaces of two films, one end of which was a heat seal tester TP-701S manufactured by Tester Sangyo Co., Ltd., with a heat bonding time of 1 second, a heat bonding pressure of 98 kPa, and a heat bonding temperature of 180. A test piece was prepared at 0 ° C. The thermal bond strength was measured according to JIS-Z1707 in an environment of 23 ° C. and 50% relative humidity. However, the test speed was 300 ± 30 mm per minute. A plurality of test pieces were measured for each of the film flow direction (MD) and the width direction (TD) and averaged.

As a film used for the base material layer, a film (trade name: Emblet PC), which is a 12 μm-thick linear straight-cut polyethylene terephthalate film manufactured by Unitika Ltd., and an aluminum foil having a thickness of 7 μm, a polyurethane anchor coating agent Then, a low density polyethylene having a density of 0.920 g / cm ³ and a thickness of 15 μm was extruded from a T-die to obtain a film that was bonded by an extrusion lamination method to form a base material layer.

  Next, as a film used for the heat-adhesive resin layer, a layer (C) EVA having a melting point of 92 ° C., a layer (A) having a melting point of 160 ° C. and 70% by weight of PP and 30% by weight of a polybutene resin are mixed. The layer (B) was a resin in which 60% by weight of the EVA, 25% by weight of the PP, and 15% by weight of a polyolefin elastomer having a density of 0.87 were mixed. Using these, the layers are coextruded so that the layer structure is in the order of layer (C), layer (B), layer (A), layer (B), layer (C), and further tripled in the film flow direction. , Stretched 2.5 times in the width direction, layer (C) 1 μm, layer (B) 2 μm, layer (A) 5 μm, layer (B) 2 μm, layer (C) 1 μm in order and thickness, total thickness 11 μm A film for a heat-adhesive resin layer of 5 layers was prepared.

  Next, the low density polyethylene was extruded onto the aluminum foil side of the base layer film, and the base layer film and the thermoadhesive resin layer film were laminated by extrusion lamination to obtain a composite film. The thickness of the low density polyethylene intervening layer was 15 μm. Table 1 shows the evaluation results of the adhesive strength of the laminated film obtained by changing the heat seal temperature. From Table 16, it can be seen that the heat bonding strength jumps between the heat sealing temperature of 140 ° C. and 160 ° C., and before and after that, a constant heat bonding strength is shown regardless of the heat sealing temperature. . That is, by a simple means of changing the heat sealing temperature, using one film, the adhesive strength of the part to be opened is an easily peelable part having a width of 15 N / 15 mm or less, that is, a heat-sealing part with good opening characteristics, It can be seen that the adhesive strength can be stably used properly for the heat-bonded portion having a sufficient adhesive strength of 20 N / 15 mm width or more.

  Using this laminated film, a gusset-type packaging bag similar to the packaging bag described in FIG. 1 was made. The width of the bag is 55 mm, the thickness of the package is 40 mm, the overall length of the bag is 315 mm, the seal width of the thermal bonding part is 2 mm, the length from the intersection 50 to the tip is 15 mm, the angle R1 is 25 °, The angle R2 was 45 °. The adhesive strength of the thermal bonding part was 6 N / 15 mm width.

  Next, a castella having a width of 50 mm, a height of 30 mm, and a length of 150 mm is placed in the packaging bag, and an oxygen absorbent (trade name Ageless, manufactured by Mitsubishi Gas Chemical Company) is placed therein. A hermetically sealed package was obtained by heat bonding with a linear seal having a width of 7 mm. Seven days after sealing, when the package was observed, it was in a depressurized state due to absorption of oxygen therein, and the film of the supporting bag was in close contact with the castella. When the picking part was picked with a finger and peeled off from the package, opening was not started with great force, and opening was easily started, and the force applied from the opening to the end was almost the same. Then, when peeled off, the entire package could be easily opened. The shape of the castella did not collapse.

  As a film for the base material layer, a PET film (Unitika, PC type) having a thickness of 12 μm in the vertical direction and a stretched nylon film (Mitsubishi Resin, Super Neal SP-R type) having a thickness of 18 μm is used. As a film of the heat-adhesive resin layer, a polyethylene-based easy peel film (Dainippon Kagaku Kogyo Co., Ltd., Differen E7300T) having a thickness of 40 μm was used, and these were dry laminated to obtain a laminated film.

  Using this laminated film, a gusset-type packaging bag was prepared in the same manner as in Example 1, and the castella was packaged in the same manner as in Example 1 to obtain a sealed package. When the picked portion of the sealed package was picked and peeled off with fingers, the opening could be started smoothly and the opening could be easily performed with almost the same force until the end. The shape of the castella was not impaired.

  Using the laminated film obtained in Example 2, a pillow type packaging bag as shown in FIG. 6 was prepared. The length of the packaging bag in the axial direction is 315 mm, the width is 55 mm, the thermal bonding part 82 is provided with one inverted V-shape, the length from the apex to the tip of the end of the packaging bag is 15 mm, and the angle R1 is The angle R2 was set to 25 degrees and 25 degrees. In addition, the adhesive strength of the heat bonding part when it was set as the package was 6 N / 15 mm in all.

  From the opening of this packaging bag, squid soaked squid with a length of about 220 mm, a width of about 30 mm and a height of about 20 mm is introduced, and after degassing, the opening is thermally bonded with a linear seal with a width of 10 mm and sealed. did. When the unsealed portion of the sealed package was picked and peeled off with fingers, the unsealing started smoothly and could be easily opened with a constant force until the end. Since almost the entire surface of the packaging bag was opened, it was possible to easily take out the squid.

It is (a) front view, (b) right side view, and (c) perspective view showing a configuration example of a gusset type packaging bag. It is a schematic diagram explaining a one-way linear cut property. It is the perspective view which showed the structural example of the package. It is a schematic diagram for demonstrating the condition of the force at the time of opening. It is a perspective view for demonstrating the opening state of a package. It is (a) front view and (b) perspective view which showed the structural example of the other package. Furthermore, (a) the front view and (b) perspective view which showed the structural example of the other package.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Packaging bag 2, 4 End part 3 Side part 5 Packing body 6 Contents 10-15 Side face 20, 21 Opening knob part 30 Ends 31, 32 End side (substantially trapezoidal leg)
33-38 edge 40 edge (cutting line)
50 Intersection 51-54 Thermal bonding portion 60, 61 Trace 70 where thermal bonding portion was peeled off Thermal bonding portion 80, 90 Unsealing knob 81, 91 Diagonal edge (trapezoidal leg)
82, 92 Reverse V-shaped thermal bonding part

Claims (5)

  A laminated bag having a base material layer and a heat-adhesive resin layer, and a substantially axisymmetric packaging bag configured with the heat-adhesive resin layer on the inside, wherein one end in the axial direction is sealed The laminated film has a straight-cut property in a direction substantially parallel to the axial direction, and the end portion has a substantially trapezoidal opening knob and a heat bonding portion sealed with easy opening. And the said heat bonding part has at least 1 shape which converges in an inverted V shape toward the said edge part, The packaging bag characterized by the above-mentioned.   Using a laminated film having a base material layer and a heat-adhesive resin layer, a side part having a deformed hexagonal cylinder shape in which two opposite sides are folded inward with the heat-adhesive resin layer inside, and the deformed hexagon A cylindrical gusset-type packaging bag in which one end in the axial direction of a cylinder is sealed, wherein the laminated film has a straight cut property in a direction substantially parallel to the axial direction, and the end is opened in a substantially trapezoidal shape. A heat-adhering portion sealed with an easy-opening property, and the heat-adhering portion has at least one shape that converges in an inverted V shape from the side surface portion toward the end portion. Characteristic packaging bag.   3. The packaging bag according to claim 1, wherein an adhesive strength of the thermal bonding portion is 2 N / 15 mm width or more and 20 N / 15 mm width or less.   The thermoadhesive resin layer comprises a layer (A) mainly composed of a high melting point resin having a melting point of 135 ° C. or higher and 180 ° C. or lower, a low melting point resin having a melting point of 80 ° C. or higher and lower than 135 ° C., and the high melting point resin And a layer (B) mainly composed of the mixed resin, wherein the difference between the melting point of the high melting point resin and the highest melting point of the low melting point resin is 20 ° C. or more, and the two layers are: The packaging bag according to any one of claims 1 to 3, wherein the packaging bags are laminated in the order of (B) and (A) from the heat bonding surface of the heat bonding resin layer. A substantially axisymmetric packaging body in which a laminated film having a base material layer and a heat-adhesive resin layer is used, and a packaged object is packaged with the heat-adhesive resin layer inside. Both ends in the direction are sealed, and the laminated film has a straight cut property in a direction substantially parallel to the axial direction, and at least one of the ends has a substantially trapezoidal opening knob. And a heat-bonding portion sealed with easy opening, wherein the heat-bonding portion has at least one shape converging in an inverted V shape toward the end portion.

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