Method for manufacturing self-supporting packaging bag, sealing member, and self-supporting packaging bag

Abstract

The present invention relates to a method for manufacturing a self-supporting packaging bag, a sealing member used in the manufacturing method, and a self-supporting packaging bag manufactured by the manufacturing method, the self-supporting packaging bag comprising a pair of flat surface parts and a bottom surface part folded in an inverted V shape at the lower part, the self-supporting packaging bag having a side sealing part and a bottom surface part sealing part, in a first sealing step including heating, pressurizing, and cooling, a first sealing step including heating, pressurizing, and cooling, and a second sealing step including heating, pressurizing, and cooling, a second sealing step including heating, pressurizing, and cooling, and a third sealing step including heating, pressurizing, and cooling, and a fourth sealing step including heating, pressurizing, and cooling, and a fourth sealing step including heating, pressurizing, and cooling, and a fourth sealing step including heating, pressurizing, and cooling. And a sealing step for forming a bottom surface sealing part in which a region including at least a part of the stepped part becomes an unsealed part, and sealing the unsealed part after the second sealing step.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a self-standing packaging bag, a sealing member for manufacturing the self-standing packaging bag, and a self-standing packaging bag manufactured by the method for manufacturing the self-standing packaging bag. Background Art

[0002] Packaging bags made of thin film materials such as synthetic resins are widely known.

[0003] As a laminate constituting such a packaging bag, a sealing layer made of a heat-bondable synthetic resin is known to be provided on the innermost layer. By using such a laminate, heat bonding can be performed on a desired area by heating and pressing to form a sealed portion, thereby forming a bag-shaped packaging bag.

[0004] There is known a packaging bag having self-standing properties. Figure 12 The conventional self-standing packaging bag SPB-C shown in the figure. Figure 12 In the conventional self-standing packaging bag SPB-C shown in the figure, a bottom face portion 12 folded in an inverted V shape is provided at the lower part of a pair of flat face portions 11, and the packaging bag is formed by forming a conventional bottom face portion sealing portion 21C and side portion sealing portions 22 on both side portions of the flat face portion.

[0005] The conventional self-standing packaging bag SPB-C has side portion sealing portions 22 on both side portions of the flat face portion 11. In addition, a boat-shaped conventional bottom face portion sealing portion 21C is provided at the lower part, and the flat face portion 11 and the bottom face portion 12 are joined by the side portion sealing portions 22 and the conventional bottom face portion sealing portion 21C.

[0006] Figure 12 The conventional self-standing packaging bag SPB-C shown in the figure is obtained by the following steps. That is, as shown in Figure 13 (a), a bottom face portion forming film 12 folded in an inverted V shape is disposed at the lower part of a pair of flat face portion forming films 11. As shown in Figure 13 (b), the bottom face portion forming film 12 is sandwiched between the two films of the flat face portion forming film 11. As shown in Figure 13 (c), first, a conventional bottom face portion sealing portion 21C is formed. Then, as shown in Figure 13 (d), side portion sealing portions 22 are formed on both side portions. At this time, cut portions 13 are provided at both ends of the bottom face portion forming film 12 folded in an inverted V shape, and on the side portion sealing portions 22, the innermost fusion layers of the pair of flat face portions 11 are sealed through the cut portions 13.

[0007] In addition, these respective sealing portions are each formed by a sealing jig, and the sealing jig is grouped such that cooling is performed after heating and pressurization. Further, when continuous heating and pressurization of the seals of all parts of the packaging bag is continued without cooling after heating and pressurization, heat adhesion to unnecessary parts may occur due to the residual heat. Therefore, cooling needs to be performed after heating and pressurization.

[0008] Figure 12 The conventional self-standing packaging bag SPB-C shown has: a two-layer portion TL formed by a pair of film-forming films 11 for the flat portion 11 constituting the self-standing packaging bag; and a four-layer portion FL formed by a pair of film-forming films 11 for the flat portion and a bottom portion-forming film 12 folded in two layers. The boundary between the two-layer portion TL and the four-layer portion FL is a stepped portion based on the overlap of the films. In the stepped portion, there are: a first stepped portion 31 caused by the folding line 14 of the bottom portion-forming film; and a second stepped portion 32 caused by the cut portion 13 provided on the bottom portion-forming film 12. Figure 14 It is a cross-sectional view of the first stepped portion 31 formed at the boundary between the two-layer portion TL and the four-layer portion FL on the conventional self-standing packaging bag SPB-C.

[0009] As Figure 12 shown, the side seal portion 22 and the conventional bottom seal portion 21C are seal portions that straddle the first stepped portion 31 and the second stepped portion 32. In particular, on the first stepped portion 31, the conventional bottom seal portion 21C seals the entire area of the stepped portion that overlaps with the side seal portion 22. However, due to the difference in thickness of the stepped portion, the pressure from the sealing bar may vary, so that the seal on the two-layer portion TL side near the stepped portion may be insufficient, resulting in insufficient adhesion. At this time, the content may leak from this part. In particular, since the conventional bottom seal portion 21C mainly seals the four-layer portion FL, near the stepped portion, more specifically, on the two-layer portion TL side of the first stepped portion 31 formed at the boundary between the four-layer portion FL and the two-layer portion TL shown in Figure 14 it is difficult to apply sufficient pressure, and it is easy to cause insufficient sealing. In addition, Figure 12 26 in

[0010] is an unsealed portion in the conventional bottom seal portion 21C, which is an unsealed portion provided to prevent wrinkles from occurring when the entire surface of the conventional bottom seal portion 21C is sealed, and is the conventional bottom unsealed portion 26.

[0011] In Patent Document 1, a method for manufacturing a packaging bag is disclosed, which includes: a lamination step of sandwiching a folded bottom sheet to form a laminate in which a pair of side sheets are laminated; and an adhesion step of adhering the side sheets and the bottom sheet of the laminate. The adhesion step includes: a first adhesion step of heating and pressing a four-layer portion where the bottom sheet of the laminate is located to adhere a lower adhesion portion; a second adhesion step of heating and pressing a two-layer portion where the bottom sheet of the laminate is not located to adhere a side adhesion portion; and a third adhesion step of heating and pressing a boundary portion between the two-layer portion where the bottom sheet of the laminate is not located and the four-layer portion where the bottom sheet of the laminate is located to adhere a boundary portion between the side adhesion portion and the lower adhesion portion. The problem of Patent Document 1 is to provide a method for manufacturing a packaging bag that can suppress liquid leakage.

[0012] In Patent Document 1, if the synthetic resin film forming the innermost heat-sealing layer is made of a resin having a melting point, then in each sealing step, even after heating and pressing and then cooling, the resin will melt each time it is heated above the melting point. Therefore, by emphasizing multiple seals, a firm seal can be ensured. Packaging bags made of polyethylene film or polypropylene film, which are often used as packaging bags, are based on this sealing mechanism.

[0013] On the other hand, as a packaging bag, there are packaging bags used when enclosing pharmaceuticals or quasi-drugs containing active ingredients such as plasters in the contents, foods and cosmetics containing fragrances or spices in the contents, etc. Such packaging bags need to reduce the adsorption amount of the fragrances, spices or active ingredients contained in the contents to the bag, and there is a high necessity to maintain the content of the fragrances, spices or active ingredients in the contents at a desired value.

[0014] Therefore, there are cases where a packaging bag is formed by a laminate that uses a resin having high non-adsorbability as the innermost heat-sealing layer. As a non-adsorption film used for this heat-sealing layer, Patent Document 2 discloses a layer made of an amorphous polyester copolymer having a glass transition temperature of 70 to 90°C. Thereby, both excellent non-adsorbability and sealing strength can be achieved, and it is easy to form a film.

[0015] As a film for forming the heat-sealing layer, when using a packaging bag made of a polyester resin with a high degree of amorphousness, it can be sealed by heating above the melting point. However, the melting point of the polyester resin is very high, around 250°C. Therefore, when heated above the melting point of the polyester resin, the adjacent layer will also melt, making it difficult to stably manufacture the packaging bag and possibly causing defects in the manufactured packaging bag.

[0016] Therefore, there is a method of softening and adhering by making the heating temperature of the sealing step lower than the melting point of the polyester resin with a high degree of amorphousness.

[0017] When using this method to manufacture a self-standing packaging bag, in the sealing process of the stepped portion, when cooling is performed after heating and pressurization, the crystallization of the amorphous portion of the polyester resin is promoted. Even if heating is performed again in the next sealing process, the crystallized molecules will not return to the amorphous state but will maintain a high degree of crystallinity. Therefore, in the first sealing process including heating, pressurization, and cooling, in the case of insufficient adhesion, even if subsequent sealing is performed by heating and pressurization multiple times, the crystallinity of the polyester molecules will increase while maintaining the state of insufficient adhesion, resulting in insufficient adhesion. Thus, in the manufacturing method described in Patent Document 1, there is a concern that a firm seal cannot be ensured.

[0018] Therefore, Patent Document 3 discloses a sealing method for a packaging bag, which is a sealing method when manufacturing a self-standing packaging bag using a laminate having a heat-sealing layer using amorphous polyester, and has: a first step of overlapping the heat-sealing layers with each other on a stepped portion where adhesion may be insufficient and joining them by sealing; a second step of melting the stepped portion using a sealing method such as an ultrasonic sealing method or a high-frequency induction sealing method with a greater amount of heat than the sealing in the first step, and the stepped portion is formed by further overlapping two laminates joined in the first step.

[0019] Patent Document Patent Document 1: Japanese Patent Application Laid-Open No. 2021-183390 Patent Document 2: Japanese Patent Application Laid-Open No. 2015-66802 Patent Document 3: Japanese Patent Application Laid-Open No. 2017-217764 Summary of the Invention However, since the manufacturing method of the packaging bag in Patent Document 3 requires an additional ultrasonic sealing mechanism and a high-frequency induction sealing mechanism in addition to the heat-sealing mechanism, the configuration of the bag-making device is complicated, which is not conducive to cost, maintenance, etc. In addition, when ultrasonic sealing and high-frequency induction sealing are performed on the basis of heat-sealing, it may cause the laminated body in that part to become extremely thin-walled and the strength to be weakened, and the resin of the heat-sealing layer in the thin-walled part will melt and flow into the content storage part, resulting in the generation of resin blocks. In addition, since ultrasonic sealing marks or high-frequency induction sealing marks will remain on the packaging bag in a visually recognizable state, the appearance of the packaging bag will deteriorate.

[0020] The technical problem to be solved by the present invention is to provide a method for manufacturing a self-standing packaging bag having stepped portions based on film overlaps, capable of effectively and sufficiently sealing near the stepped portions, having excellent appearance of the stepped portions, and capable of preventing leakage of the contents, a sealing member for manufacturing the self-standing packaging bag, and a self-standing packaging bag manufactured by using the method for manufacturing the self-standing packaging bag.

[0021] The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, found that by using a specific method for manufacturing a self-standing packaging bag, a sealing member for manufacturing the self-standing packaging bag, and a self-standing packaging bag manufactured by the method for manufacturing the self-standing packaging bag, the above problems can be solved, and thus the present invention was completed.

[0022] That is, the present invention provides the following method for manufacturing a packaging bag, a sealing member for manufacturing the packaging bag, and a packaging bag manufactured by the method for manufacturing the packaging bag.

[0023] (Technical solution 1) A method for manufacturing a self-standing packaging bag, the self-standing packaging bag being composed of a pair of flat portions and a bottom portion folded in a reverse V shape at the lower part, having side sealing portions and a bottom portion sealing portion, and having stepped portions based on the overlap of films of a two-layer portion and a four-layer portion, the two-layer portion being formed by overlapping the pair of flat portions, and the four-layer portion being formed by overlapping the pair of flat portions and the bottom portion, characterized in that in the first sealing step, heating and pressing are performed in a state where at least a part of the region including the stepped portion is an unsealed portion, and then cooling is performed to form the bottom portion sealing portion, and after the second sealing step, the unsealed portion is heated, pressed, and cooled for sealing.

[0024] (Technical solution 2) The method for manufacturing a self-standing packaging bag according to Technical solution 1, characterized in that the pair of flat portions and the bottom portion are composed of films having a heat-adhesive layer containing a polyester resin.

[0025] (Technical solution 3) A sealing member used in a method for manufacturing a self-standing packaging bag, the self-standing packaging bag being composed of a pair of flat portions and a bottom portion folded in a reverse V shape at the lower part, having side sealing portions and a bottom portion sealing portion, and having stepped portions based on the overlap of films of a two-layer portion and a four-layer portion, the two-layer portion being formed by overlapping the pair of flat portions, and the four-layer portion being formed by overlapping the pair of flat portions and the bottom portion, characterized in that it is a heat-sealing die for forming the bottom portion sealing portion in the first sealing step so that at least a part of the region including the stepped portion is an unsealed portion.

[0026] (Technical Solution 4) A self-standing packaging bag, characterized in that it is manufactured by the manufacturing method of the self-standing packaging bag described in Claim 1 or 2.

[0027] (Technical Solution 5) A manufacturing method of a self-standing packaging bag, the self-standing packaging bag is composed of a pair of flat portions and a bottom portion folded in half into an inverted V shape at the lower part, having side sealing portions and a bottom portion sealing portion, and having a stepped portion based on the overlap of films of a two-layer portion and a four-layer portion, the two-layer portion is formed by overlapping the pair of flat portions, and the four-layer portion is formed by overlapping the pair of flat portions and the bottom portion, and a bag-making machine having a set of sealing jigs that are cooled after heating and pressing is used, and it is characterized in that On the stepped portion, there is an area sealed only by the last set of sealing jigs.

[0028] According to the present invention, a manufacturing method of a self-standing packaging bag can be provided. In the method of manufacturing a self-standing packaging bag having a stepped portion based on the overlap of films, even when using a film whose heat-sealing layer is made of a polyester resin with high amorphousness, the stepped portion can be reliably sealed, the sealing appearance of the stepped portion is excellent, and leakage of liquid contents can be suppressed. In addition, a sealing member for manufacturing the self-standing packaging bag and a self-standing packaging bag manufactured by using the manufacturing method of the self-standing packaging bag can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of a self-standing packaging bag obtained by the manufacturing method of the self-standing packaging bag according to the present invention.

[0030] Figure 2 It is a schematic diagram of an embodiment of the process included when manufacturing a self-standing packaging bag by the manufacturing method of the self-standing packaging bag according to the present invention.

[0031] Figure 3 It is a schematic diagram of an embodiment of a film for forming a bottom portion when manufacturing a self-standing packaging bag by the manufacturing method of the self-standing packaging bag according to the present invention.

[0032] Figure 4 It is a cross-sectional view of an embodiment when overlapping a pair of films for forming flat portions and a film for forming a bottom portion when manufacturing a self-standing packaging bag by the manufacturing method of the self-standing packaging bag according to the present invention.

[0033] Figure 5This is a schematic diagram showing an embodiment of the process involved in manufacturing a self-standing packaging bag by the manufacturing method of the self-standing packaging bag according to the present invention.

[0034] Figure 6 This is a schematic diagram showing an embodiment of the sealing member for forming the bottom portion used in manufacturing a self-standing packaging bag by the manufacturing method of the self-standing packaging bag according to the present invention.

[0035] Figure 7 This is a schematic diagram showing an embodiment of the process involved in manufacturing a self-standing packaging bag by the manufacturing method of the self-standing packaging bag according to the present invention.

[0036] Figure 8 This is a schematic diagram showing an embodiment of the process involved in manufacturing a self-standing packaging bag by the manufacturing method of the self-standing packaging bag according to the present invention.

[0037] Figure 9 This is a schematic diagram showing an embodiment of the sealing member for forming the bottom portion used in manufacturing the self-standing packaging bag according to the present invention.

[0038] Figure 10 This is a schematic diagram showing an embodiment of the sealing member for forming the bottom portion used in manufacturing a self-standing packaging bag according to the prior art.

[0039] Figure 11 This is a schematic diagram showing an embodiment of the sealing member used in manufacturing the self-standing packaging bag according to the present invention.

[0040] Figure 12 This is a schematic diagram of a self-standing packaging bag according to the prior art.

[0041] Figure 13 This is a schematic diagram showing the manufacturing process of a self-standing packaging bag according to the prior art.

[0042] Figure 14 This is a cross-sectional view of the stepped portion formed at the boundary between the two-layer portion and the four-layer portion on the self-standing packaging bag.

[0043] Symbol Explanation SPB - self - standing packaging bag; SPB - C - existing self - standing packaging bag; Ap - upper opening part; 11 - flat part / film for forming flat part; 12 - bottom part / film for forming bottom part; 13 - cut - off part; 14 - fold line of bottom - part - forming film; 15 - predetermined cutting line; 16 - boundary line of side - part sealing part; 21 - bottom - part sealing part; 21a - lower - end sealing; 21b - bottom - shape - forming sealing; 21ba - inclined sealing; 21bb - arc - shaped sealing; 21C - existing bottom - part sealing part; 22 - side - part sealing part; 23 - special sealing part for step part; 24a - unsealed part of the first step part; 24b - unsealed part of the second step part; 25 - unsealed part of bottom part; 26 - existing unsealed part of bottom part; 31 - first step part; 32 - second step part; TL - two - layer part; FL - four - layer part; 41 - sealing member for forming bottom part; 42 - notch part of step part; 43 - notch part of side part; 44 - bottom - shape - forming sealing formation part; 44a - inclined - sealing formation part; 44b - arc - shaped - sealing formation part; 45 - lower - end - sealing formation part; d - width dimension; 51 - existing sealing member for forming bottom part; 52 - existing notch part of bottom part. Detailed Description of the Invention

[0044] Next, a manufacturing method of a self - standing packaging bag according to the present invention, a sealing member for the manufacturing method of the self - standing packaging bag, and a self - standing packaging bag manufactured by the manufacturing method of the self - standing packaging bag will be described in detail.

[0045] [Manufacturing Method of Self - Standing Packaging Bag] The manufacturing method of the self - standing packaging bag according to the present invention is a manufacturing method of a self - standing packaging bag which is composed of a pair of flat parts and a bottom part folded in an inverted V - shape at the lower part, has a side - part sealing part and a bottom - part sealing part, and has a step part based on the overlap of films of a two - layer part and a four - layer part. The two - layer part is a two - layer part where a pair of flat parts overlap, and the four - layer part is a four - layer part where the pair of flat parts and the bottom part overlap. The method is characterized in that in the first sealing process, heating and pressing are performed in a state where at least a part of the area including the step part is an unsealed part, and then cooling is performed to form the bottom - part sealing part, and after the second sealing process, the unsealed part is heated, pressed, and cooled for sealing.

[0046] In addition, the manufacturing method of the self-standing packaging bag according to the present invention is a manufacturing method of a self-standing packaging bag, which is composed of a pair of flat portions and a bottom portion folded in half into an inverted V shape at the lower part, has side seal portions and a bottom portion seal portion, and has a stepped portion based on the overlap of the films of the two-layer portion and the four-layer portion. The two-layer portion is the two-layer portion where the pair of flat portions overlap, and the four-layer portion is the four-layer portion where the pair of flat portions and the bottom portion overlap. A bag-making machine is used, and the bag-making machine has a plurality of sets of one set of seal clamps that are cooled after heating and pressurization. It is characterized in that, on the stepped portion, there is an area sealed only by the last set of seal clamps.

[0047] The self-standing packaging bag manufactured by the manufacturing method of the self-standing packaging bag according to the present invention is not particularly limited as long as it is a self-standing packaging bag having a stepped portion based on the overlap of the films. These self-standing packaging bags may also have, for example, a zipper or a stopper.

[0048] <Self-standing packaging bag> Figure 1 It is a schematic diagram of the self-standing packaging bag SPB manufactured by the manufacturing method of the self-standing packaging bag according to the embodiment of the present invention. In addition, in the self-standing packaging bag SPB in this embodiment, the pair of flat portions 11, the bottom portion 12 having the cut-out portion 13, the side seal portions 22, the two-layer portion TL, the four-layer portion FL, the first stepped portion 31, and the second stepped portion 32 are the same parts as those of the existing self-standing packaging bag SPB-C, and thus the same reference numerals are used for description.

[0049] Figure 1The shown self-standing packaging bag SPB has a pair of flat portions 11 and a bottom portion 12 that is folded in half at the lower part to form an inverted V shape. The self-standing packaging bag SPB includes: a two-layer portion TL formed by a pair of flat portions 11; and a four-layer portion FL formed by a pair of flat portions 11 and a bottom portion 12 that is folded in half into two layers. The boundary between the two-layer portion TL and the four-layer portion FL is a stepped portion based on the overlap of the films. In particular, the stepped portion formed with the bottom portion forming film fold line 14 of the bottom portion 12 as the boundary is the first stepped portion 31. In addition, the self-standing packaging bag SPB has side seal portions 22 on both side portions and a bottom surface seal portion 21 on the bottom. The bottom surface seal portion 21 serves as both the lower end seal of the self-standing packaging bag SPB and the seal for determining the shape of the bottom portion of the self-standing packaging bag SPB. It is a seal portion where the lower end seal 21a and the bottom surface shape forming seal 21b are integrated. The lower end seal 21a extends linearly in the width direction at the lower end of the self-standing packaging bag SPB. The two sides of the bottom surface shape forming seal 21b are linear inclined seals 21ba, and the center is an arc-shaped seal 21bb. In addition, the self-standing packaging bag SPB forms a first stepped portion unsealed portion 24a, a second stepped portion unsealed portion 24b, and a bottom portion unsealed portion 25 through the shape of the bottom surface seal portion 21. The first stepped portion unsealed portion 24a is an unsealed portion that includes at least a part overlapping with the first stepped portion 31. The second stepped portion unsealed portion 24b is an unsealed portion that includes at least a part overlapping with the second stepped portion 32, and the second stepped portion 32 is caused by a cutout portion 13 provided on the bottom portion forming film 12. In addition, in Figure 1 on the self-standing packaging bag SPB, in order to prevent wrinkles from being generated due to full-surface sealing, an unsealed portion is formed between the bottom surface shape forming seal 21b and the lower end seal 21a of the bottom surface seal portion 21, and the bottom portion unsealed portion 25 is formed. The bottom portion unsealed portion 25 includes the second stepped portion unsealed portion 24b. That is, the second stepped portion unsealed portion 24b and the bottom portion unsealed portion 25 are integrated. In addition, the first stepped portion unsealed portion 24a is sealed by the side seal portion 22 and the stepped special seal portion 23 described later, and it is not an unsealed portion on the self-standing packaging bag SPB. According to the shape of the bottom surface seal portion 21, the opening shape of the bottom portion can be determined as a circle, an ellipse, etc., and the self-standing packaging bag SPB can be given self-standing properties.

[0050] <Film> In the method for manufacturing the self-standing packaging bag SPB according to the present embodiment, the film used is not particularly limited as long as at least one surface thereof is a heat-sealing layer and the innermost layer serving as the inner surface of the self-standing packaging bag SPB can be a heat-sealing layer. For example, it may be a single-layer film composed only of a heat-sealing layer, or a laminated film having a heat-sealing layer provided on at least one surface of a base material layer. In the present embodiment, a laminated film having a heat-sealing layer on one surface of the base material layer is preferably used. As such a laminated film, it may also have a base material layer and a heat-sealing layer, and may have an intermediate layer or the like therebetween as needed. As the laminated film, for example, the innermost layer serving as the inner surface of the packaging bag may be a heat-sealing layer, the outermost layer serving as the surface of the packaging bag may be a base material layer having heat resistance, and there may be one or more intermediate layers between the base material layer and the heat-sealing layer.

[0051] In addition, since the sealing member in the sealing process directly contacts the heat-sealing layer, the packaging bag made of a single-layer film composed only of a heat-sealing layer is likely to generate wrinkles on the surface of the packaging bag. Therefore, by laminating the heat-sealing layer with other layers such as a base material layer to form a laminate, the generation of wrinkles on the surface of the packaging bag can be suppressed.

[0052] (Heat-sealing layer) On the film used in the method for manufacturing the self-standing packaging bag SPB according to the present embodiment, the heat-sealing layer is a layer that can bond the heat-sealing layers to each other by applying heat and pressure. The resin constituting the heat-sealing layer is not particularly limited as long as it is a resin having heat adhesiveness. For example, one or more selected from polyester resins, polyolefin resins, propylene resins, vinyl acetate resins, polyamide resins, etc. can be cited. In the present embodiment, the resin constituting the heat-sealing layer contains a polyester resin.

[0053] When using a resin containing a polyester resin as the resin constituting the heat-sealing layer, as the polyester resin, for example, polyethylene terephthalate resins are preferably used. Polyester resins such as polyethylene terephthalate resins can impart heat adhesiveness even when heated below the melting point by controlling their crystallinity.

[0054] As a material containing a polyester resin, a polyester resin composition film obtained by thinning a composition containing a polyester resin, a softening agent, a binder, and a molding aid is generally used. The polyester resin composition film can control the crystallinity within a desired range by rapid cooling during film formation. By controlling the crystallinity, the polyester resin composition film can impart heat adhesiveness even when heated below the melting point. And since the polyester resin has non-adsorbability to pharmaceutical ingredients or fragrances, etc., it can have both non-adsorbability and heat adhesiveness only by the polyester resin composition film without laminating two layers of a non-adsorbing layer and a heat-sealing layer.

[0055] As an example of the polyester resin composition, for example, a polyethylene terephthalate resin composition can be cited, which consists of 0.1 to 3 parts by mass of a styrene-(meth)acrylic acid methyl ester-glycidyl methacrylate copolymer as a binder, 3 to 20 parts by mass of a cyclohexanedimethanol-ethylene glycol-terephthalic acid condensate (PCTG) as a softening agent, and 0.05 to 1.5 parts by mass of calcium stearate as a molding aid, based on 100 parts by mass of polyethylene terephthalate. As the polyethylene terephthalate, polyethylene terephthalate having an inherent viscosity of, for example, 0.6 dl / g or more and 0.8 dl / g or less can be used. In addition, the epoxy value in the styrene-(meth)acrylic acid methyl ester-glycidyl methacrylate copolymer is, for example, 0.5 meq / g or more and 4.0 meq / g or less.

[0056] In order for the hot-melt layer containing the polyester resin to exhibit hot melt adhesiveness even when heated below the melting point, the crystallinity range of the polyester resin is, for example, 30% or less, preferably 25% or less, more preferably 20% or less, and further preferably 18% or less. The lower limit value can be 0%. The crystallinity of the polyester resin in the present embodiment is within this range. By using a differential scanning calorimeter (DSC: Differential scanning calorimetry), the crystallinity can be calculated by multiplying the value obtained by dividing the heat of fusion when the polyester is melted by the heat of fusion of fully crystalline polyester (140 J / g in the case of polyethylene terephthalate) by 100.

[0057] In addition, the above composition of the polyester resin in the hot-melt layer is an example and is not limited thereto. Also, the resin of the hot-melt layer is not limited to the polyester resin. Although in the present embodiment, the resin constituting the hot-melt layer contains a polyester resin, any hot-melt layer can be appropriately used.

[0058] (Base material layer) In the film used in the method for manufacturing the self-supporting packaging bag according to the present embodiment, as the base material layer of the laminated film, there is no particular limitation, and a base material layer having good mechanical applicability and printing applicability is preferred. As such a base material layer, for example, synthetic resin films such as polyester resin films (such as polyethylene terephthalate resin films), polyamide resin films (such as nylon resin films), polyolefin resin films (such as polypropylene resin films), cyclic olefin resin films (such as polynorbornene resin films, polydicyclopentadiene resin films), polyvinyl alcohol resin films (such as polyvinyl alcohol resin films, ethylene-vinyl alcohol copolymer resin films), polycarbonate resin films, polyacetal resin films, multi-layer co-extruded films of these resins, laminates of these resins or films, non-woven fabrics, paper, metal foils, etc. can be cited.

[0059] These films can be either non-stretched films or stretched films stretched in a uniaxial or biaxial direction.

[0060] In addition, as the film for the base material layer, a vapor-deposited film provided with a vapor-deposited layer can also be used. As the vapor-deposited layer, for example, a layer composed of one or more inorganic substances selected from aluminum, silicon oxide, aluminum oxide, indium oxide, tin oxide, zirconium oxide, magnesium oxide, etc. can be cited.

[0061] The thickness of the base material layer is not particularly limited. For example, it is 3 μm or more, preferably 5 μm or more, more preferably 6 μm or more, further preferably 9 μm or more, and for example, it is 100 μm or less, preferably 60 μm or less, more preferably 50 μm or less.

[0062] (Intermediate layer) Among the films used in the method for manufacturing the self-supporting packaging bag according to the present embodiment, from the viewpoint of protecting the contents, it is preferable that the intermediate layer of the laminated film is formed of a raw material having barrier properties. The barrier properties include light-shielding properties against light such as visible light or ultraviolet light, gas barrier properties against oxygen or water vapor, heat insulation properties for blocking heat, etc. Among these barrier properties, a raw material having a desired function is used as the intermediate layer.

[0063] The raw material having barrier properties is not particularly limited. For example, metal foils such as aluminum, iron, copper, and tin, films such as polyvinyl chloride, polycarbonate, polyvinyl alcohol, saponified ethylene-vinyl acetate copolymer, and polyvinylidene chloride can be cited. In addition, a film in which polyvinylidene chloride is coated on the film described for the base material layer, a film in which inorganic substances such as aluminum, silicon oxide, aluminum oxide, indium oxide, tin oxide, zirconium oxide, and magnesium oxide are vapor-deposited on these films, a non-woven fabric or a foamed film having heat insulation properties can be cited.

[0064] In addition to or instead of the barrier properties, the intermediate layer can also have various functions. As the functions of the intermediate layer, for example, mechanical toughness, bending resistance, puncture resistance, impact resistance, cold resistance, heat resistance, chemical resistance, tear resistance, etc. can be appropriately selected according to needs and / or required functions.

[0065] The film used as the intermediate layer can be either a non-stretched film or a stretched film stretched in a uniaxial or biaxial direction. And the intermediate layer can be not only one layer but also two or more layers.

[0066] The thickness of the intermediate layer is not particularly limited. For example, it is 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and for example, it is 50 μm or less, preferably 30 μm or less, more preferably 20 μm or less.

[0067] (Lamination method of laminated film) In the method for manufacturing a self-standing packaging bag according to the present embodiment, when a laminated film is used on the film, the lamination method of each layer of the base material layer, the heat-sealing layer, and the intermediate layer provided as needed that constitute the laminated film is not particularly limited. For example, known lamination methods such as dry lamination, extrusion lamination, solventless lamination, thermal lamination, and co-extrusion can be applied, and multiple lamination methods can also be combined as needed.

[0068] In addition, when a heat-sealing layer that imparts heat adhesiveness by controlling the crystallinity of a polyester resin is used, if heat is applied during the lamination process, there is a possibility of affecting the heat adhesiveness. Therefore, lamination methods such as dry lamination or solventless lamination that do not promote the crystallization of polyester are preferred.

[0069] <Manufacturing Method of Self-Standing Packaging Bag According to Embodiment> The manufacturing method of the self-standing packaging bag SPB according to the present embodiment is mainly a method used for manufacturing a self-standing packaging bag when the resin constituting the heat-sealing layer of the film contains a polyester resin. Hereinafter, in the manufacturing method of the self-standing packaging bag SPB according to the present embodiment, a method for continuously manufacturing the self-standing packaging bag SPB will be described for the manufacturing method of the self-standing packaging bag SPB when the heat-sealing layer of the film contains a polyester resin.

[0070] Figure 2 FIG. is a schematic view showing that, in a state where the upper opening portions Ap of two self-standing packaging bags SPB are butted, in order to continuously manufacture the self-standing packaging bags SPB, a pair of flat portion forming films 11 and a pair of bottom portion forming films 12 after being folded are overlapped and conveyed. In Figure 2 each film is conveyed from a film roll (not shown) on the right side toward the left side, and in the width direction of the flat portion forming film 11, two bags with the upper opening portions Ap of the self-standing packaging bags SPB butted can be manufactured each time.

[0071] A pair of flat portion forming films 11 are conveyed with the heat-sealing layers facing each other. Moreover, on both side portions in the conveying direction of a pair of flat portion forming films 11, between the pair of flat portion forming films 11, with the heat-sealing layer on the front side, along the conveying direction, the bottom portion forming film 12 folded on the bottom portion forming film folding line 14 is sandwiched and conveyed with the bottom portion forming film folding lines 14 facing each other. In addition, the bottom portion forming film 12 is provided with cut portions 13 at regular intervals.

[0072] Figure 3 FIG. is a schematic view of the folded bottom portion forming film 12 sandwiched between a pair of flat portion forming films 11. In Figure 3 the cutting predetermined line 15 is the boundary line between the packaging bags when they become the self-standing packaging bags SPB, and is the line to be cut after sealing. AsFigure 3 As shown, after the bottom surface forming film 12 is unwound from the film roll, cut portions 13 are provided at positions on both sides of the self-standing packaging bag at regular intervals.

[0073] As Figure 2 and Figure 4 As shown in (a), a pair of flat surface forming films 11 and the folded bottom surface forming film 12 are overlapped while being conveyed. Thus, a first stepped portion 31 is formed with the bottom surface forming film fold line 14 on the folded bottom surface forming film 12 as a boundary, and a second stepped portion 32 is formed with the edge of the cut portion 13 as a boundary.

[0074] Figure 4 Figure (b) shows a cross-sectional view of a state where a pair of flat surface forming films 11 and the folded bottom surface forming film 12 folded therebetween are overlapped. As Figure 4 shown in (b), the first stepped portion 31 is formed at the boundary between the two-layer portion TL and the four-layer portion FL with the bottom surface forming film fold line 14 as a boundary. The two-layer portion TL is composed of a pair of flat surface forming films 11, and the four-layer portion FL is formed by sandwiching the folded bottom surface forming film 12 between a pair of flat surface forming films 11. The second stepped portion 32 is formed at the boundary between the four-layer portion FL and the two-layer portion TL, which is the edge portion of the cut portion 13, in the four-layer portion FL formed by sandwiching the folded bottom surface forming film 12 between a pair of flat surface forming films 11. In addition, the cross-sectional view of the first stepped portion 31 is the same as that of the Figure 14 prior art shown.

[0075] The manufacturing method of the self-standing packaging bag in this embodiment is as described above. As Figure 4 shown in (b), the folded bottom surface forming film 12 is sandwiched between a pair of flat surface forming films 11 and overlapped, and first, a bottom surface sealing portion 21 is formed in the first sealing process.

[0076] (First Sealing Process) In the first sealing process in this embodiment, a bottom surface sealing portion 21 is formed. Figure 5 A schematic diagram showing the first sealing process. Figure 5It is a diagram showing the amount of one bag in the continuous manufacture of the self-supporting packaging bag SPB. The bottom surface seal portion 21 also serves as the lower end seal of the self-supporting packaging bag SPB and the seal that determines the shape of the bottom surface portion of the self-supporting packaging bag SPB. The detailed overall shape will be described later. In the first sealing process, the region in the first step portion 31 that includes a part overlapping with the side seal portion 22 to be sealed later is heated and pressed, and then cooled to form the bottom surface seal portion 21. At this moment, in the film folding line 14 for forming the bottom surface portion, that is, in the first step portion 31, the region that includes at least a part of the remainder overlapping with the side seal portion 22 to be sealed later is not sealed, but the unsealed portion 24a of the first step portion is formed. In Figure 5 In it, the positions of the left and right side seal portions 22 are respectively between the left and right ends of the self-supporting packaging bag SPB and the side seal portion boundary line 16. Although the bottom surface seal portion 21 may not completely seal the first step portion 31 overlapping with the side seal portion 22, in order to prevent misalignment between the flat surface portion forming film 11 and the bottom surface portion forming film 12, it is preferable to seal only a part of the first step portion 31 that overlaps with the side seal portion 22. The heat-sealing die for forming the bottom surface seal portion 21, that is, the sealing member, is shaped such that while forming the unsealed portion 24a of the first step portion by not sealing the region in the first step portion 31 that includes at least a part overlapping with the side seal portion 22, it seals the region in the first step portion 31 that includes a part overlapping with the side seal portion 22 other than the unsealed portion 24a of the first step portion. The details of this sealing member will be described later.

[0077] Here, in the manufacturing method of the self-supporting packaging bag in the present embodiment, the hot melt layer containing a polyester resin used in the film is joined to each other by heating and pressing below the melting point of the polyester resin, and by cooling it, it is sealed while losing the hot melting property. Once cooled, even if heated again, the polyester resin will not melt again. Therefore, when manufacturing a self-supporting packaging bag using a hot melt layer containing a polyester resin, as in the past, when sealing the entire region of the first step portion 31 overlapping with the side seal portion 22 on the existing bottom surface seal portion 21C, on the two-layer portion TL side of the first step portion 31, when the films are not sufficiently joined to each other, the molecules will directly crystallize, the crystallinity will increase, and the hot melting property will be lost. Even if the first step portion 31 where the films are not sufficiently joined to each other is heated again in a subsequent sealing process, the crystallized molecules will maintain the crystalline state, so the hot melting property will not be restored, and the joining of the films to each other will become insufficient, which may cause poor sealing at this part when it becomes a self-supporting packaging bag.

[0078] In the method for manufacturing the self-standing packaging bag SPB according to the present embodiment, in the first sealing step, by heating and pressing the bottom surface sealing portion 21 and then cooling it, the region in the first stepped portion 31 that includes at least a part overlapping with the side surface sealing portion 22 is not sealed, and the unsealed portion 24a of the first stepped portion is formed. At this time, the hot melt layers in the unsealed portion 24a of the first stepped portion do not weld to each other, so that crystallization of the polyester resin in the hot melt layer in the unsealed portion 24a of the first stepped portion can be prevented. After the heating and pressing in the first sealing step and the subsequent cooling are completed, the unsealed portion 24a of the first stepped portion is an unsealed portion where the films do not join to each other at all. In the final sealing step after the second sealing step described later, the unsealed portion 24a of the first stepped portion is firmly sealed by performing heating and pressing and cooling only once.

[0079] Similarly, in the first sealing step in the present embodiment, the region including the second stepped portion 32 is not sealed, and the unsealed portion 24b of the second stepped portion is provided and the bottom surface sealing portion 21 is formed. At this time, the hot melt layers of the pair of flat portion forming films 11 in the two-layer portion TL in the unsealed portion 24b of the second stepped portion do not join to each other, and the hot melt layers of the flat portion forming film 11 of the four-layer portion FL and the bottom surface forming film 12 do not join to each other, so that crystallization of the polyester resin in the hot melt layer can be prevented. After the first sealing step is completed, the unsealed portion 24b of the second stepped portion is an unsealed portion where the respective films do not join to each other at all.

[0080] Figure 6 The bottom surface forming sealing member 41 for forming the bottom surface sealing portion 21 in the first sealing step is shown. The bottom surface sealing portion 21 also serves as the lower end sealing of the self-standing packaging bag SPB and the sealing for determining the shape of the bottom surface of the self-standing packaging bag SPB. As long as the bottom surface of the self-standing packaging bag SPB can be formed, its shape and the like are not particularly limited. In Figure 5 it, the bottom surface sealing portion 21 is a sealing portion in which the lower end sealing 21a and the bottom surface shape forming sealing 21b are integrated. The lower end sealing 21a extends linearly in the width direction at the lower end of the self-standing packaging bag SPB. Both sides of the bottom surface shape forming sealing 21b are linear inclined sealings 21ba, and the center is formed by an arc-shaped sealing 21bb. In addition, the lower end sealing 21a overlaps a part of the arc-shaped upper sealing 21bb. The two outer sides of the inclined sealing 21ba are the unsealed portions 24a of the first stepped portion, and between the bottom surface shape forming sealing 21b and the lower end sealing 21a is the unsealed portion 24b of the second stepped portion. In the first sealing step, by initially forming the bottom surface sealing portion 21, displacement of the pair of flat portion forming films 11 and the bottom surface forming film 12 can be prevented.

[0081] Figure 6The bottom surface forming seal member 41 used in the first sealing process shown is a heat-sealing die for forming the bottom surface seal portion 21, having the same shape as the bottom surface seal portion 21, and including a bottom surface shape forming seal portion 44 for forming the bottom surface shape forming seal 21b and a lower end seal forming portion 45 for forming the lower end seal 21a. In addition, the bottom surface forming seal member 41 has a stepped portion cutout portion 42, and the stepped portion cutout portion 42 can form the first stepped portion unsealed portion 24a and does not seal at least a part of the stepped portion based on the overlap of the films. Figure 6 The shown bottom surface forming seal member 41 does not seal at least a part of either the first stepped portion 31 or the second stepped portion 32, and a stepped portion cutout portion 42 for forming the first stepped portion unsealed portion 24a is formed corresponding to the first stepped portion 31, and a side portion cutout portion 43 for forming the second stepped portion unsealed portion 24b is formed corresponding to the second stepped portion 32. In addition, although in Figure 6 the shape of the bottom surface forming seal member 41 is configured such that the entire length of the second stepped portion 32 is not sealed in the side portion cutout portion 43, it is sufficient that at least a part of the second stepped portion 32 is not sealed. In addition, if planar sealing is performed in the bottom surface seal portion 21, wrinkles may be generated. Therefore, in addition to the side portion cutout portion 43 that avoids the second stepped portion, a cutout portion for forming an unillustrated bottom surface unsealed portion 25 may be provided. The cutout portion for forming the bottom surface unsealed portion 25 may be formed separately from the side portion cutout portion 43, or may be integrally formed with the stepped portion cutout portion 42 and / or the side portion cutout portion 43.

[0082] In addition, with respect to the second stepped portion 32, it is not associated with the content accommodating portion of the self-standing packaging bag SPB, and thus there is no need to perform a seal with a strong seal strength that can effectively fill the stepped portion as required for the first stepped portion 31. Therefore, in the first sealing process, in order not to provide the second stepped portion unsealed portion 24b, it may be configured such that the side portion cutout portion 43 is not provided on the bottom surface forming seal member 41. In addition, when the cutout portions for forming the side portion cutout portion 43 and the bottom surface unsealed portion 25 are not provided on the bottom surface forming seal member 41 and the bottom surface seal portion 21 is sealed in a planar manner, wrinkles may be generated as described above. Therefore, it is preferable to provide a cutout portion that does not seal at least a part of the second stepped portion 32.

[0083] In the present embodiment, on the side seal portion 22 that is sealed in a subsequent process, in order to bring the pair of flat portion forming films 11 into contact with each other through the cut portion 13 of the bottom surface forming film 12 and to be in a state where the side portion of the self-standing packaging bag SPB is closed, and in order to prevent crystallization of the polyester resin of the heat adhesive layer after the first sealing process, it is preferable to avoid bringing the flat portion forming films 11 corresponding to the cut portion 13 into contact with each other in the first sealing process. Therefore, it is preferable to use the bottom surface seal portion 21 that can form at least a part of the second step portion 32 that overlaps with the side seal portion 22 and is not sealed, and the bottom surface forming seal member 41 having a cut portion for forming the side cut portion 43 and the bottom surface unsealed portion 25.

[0084] The step portion cut portion 42 is provided to form the first step portion unsealed portion 24a on the bottom surface forming seal member 41. That is, when the bottom surface forming seal member 41 is used in the first sealing process, the first step portion unsealed portion 24a is formed, and the region including at least a part of the first step portion 31 that overlaps with the side seal portion 22 is not sealed. The step portion cut portion 42 on the bottom surface forming seal member 41 is, for example, as Figure 6 shown, the positions of both ends of the inclined seal forming portion 44a in the bottom surface shape forming seal forming portion 44 are located more inward in the width dimension d than the positions of both ends of the lower end seal forming portion 45, and the portion of the width dimension d at the front end of the inclined seal forming portion 44a is the step portion cut portion 42. The bottom surface seal portion 21 using the bottom surface forming seal member 41 has a shape in which the inclined seal 21ba extends to a range overlapping with the side seal portion 22 when it becomes the self-standing packaging bag SPB and does not reach the positions of both sides of the flat portion 11. Thus, between both end portions of the inclined seal 21ba and both sides of the flat portion 11, the first step portion unsealed portion 24a including a part of the first step portion 31 is formed so as not to be sealed. The shape of the step portion cut portion 42 is not limited to this, as long as it can form an unsealed portion shape such that at least a part of the first step portion 31 overlapping with the side seal portion 22 becomes the first step portion unsealed portion 24a. Although in Figure 6 the shape of the bottom surface forming seal member 41 is such that both ends of the inclined seal forming portion 44a extend linearly in the vertical direction, both ends of the inclined seal forming portion 44a can also be, for example, convex or concave arc-shaped or linearly extending obliquely. In addition, the shape of the bottom surface forming seal member 41 can also be a shape of the bottom surface seal portion 21 in which the periphery of the first step portion unsealed portion 24a that can be formed is surrounded by a sealed portion and a part of the first step portion 31 overlapping with the side seal portion 22 becomes an unsealed portion.

[0085] The size of the stepped cut portion 42 for forming the unsealed portion 24a of the first stepped portion in the bottom surface forming sealing member 41 that includes at least a part of the first stepped portion 31 is not particularly limited.

[0086] Preferably Figure 6 As shown, the width of the stepped cut portion 42 on the bottom surface forming sealing member 41 with respect to the side sealing portion 22 formed on one side is, for example, 80% or less, preferably 70% or less, more preferably 50% or less, and for example, 5% or more, preferably 10% or more, more preferably 20% or more unsealed.

[0087] In Figure 6 As shown, in the bottom surface forming sealing member 41, a side cut portion 43 for forming the unsealed portion 24b of the second stepped portion may also be provided in the area including the second stepped portion 32. When the side cut portion 43 is provided, preferably with respect to the entire length of the second stepped portion 32, it is, for example, 100% or less, preferably 80% or less, more preferably 70% or less, further preferably 50% or less, and for example, 0% or more, preferably 5% or more, more preferably 10% or more, further preferably 20% or more unsealed.

[0088] The heating temperature of the first sealing process for forming the bottom surface sealing portion 21 can be appropriately set according to the resin of the heat - adhesive layer. In the present embodiment, since the heat - adhesive layer contains a polyester resin, it is below the melting point of the polyester resin, i.e., about 260°C, and for example, it can be 130°C or more and 160°C or less. When the layer other than the heat - adhesive layer on the flat surface forming film 11 and / or the bottom surface forming film 12 is a polyester resin or an olefin - based resin, when heated to a temperature above the melting point of the polyester resin, the resin of these layers will also melt. Therefore, it is preferable to perform heating at a temperature lower than the melting point of the polyester resin.

[0089] By using a polyester resin for the heat - adhesive layer and heating at a temperature lower than the melting point of the polyester, the polyester resin can be softened and the films can be joined to each other. This can be considered that the movement of amorphous polyester molecules becomes active, and the films are joined to each other by the entanglement of amorphous molecules, and a firm sealing portion is formed by cooling it.

[0090] In the first sealing process, the bottom surface forming sealing member 41 is used for heating and pressing, and then a firm bottom surface sealing portion 21 can be formed by cooling.

[0091] In the first sealing process, if cooling is not performed after heating and pressing, it may cause misalignment between the flat surface forming film 11 and the bottom surface forming film 12. In addition, since it may adhere to unnecessary parts due to the residual heat, cooling after heating and pressing must be performed.

[0092] After the first sealing step is completed, the unsealed portion 24b of the second stepped portion is an unsealed portion where the films are not joined to each other at all.

[0093] (Second Sealing Step) Figure 7 Fig. (a) is a schematic view of the second sealing step performed after the first sealing step. Figure 7 Fig. (b) is Figure 7 an enlarged view of the circular surrounding portion of Fig. (a). As shown in Figure 7 Fig. (a) and Figure 7 Fig. (b), a stepped portion special seal portion 23 is formed in the second sealing step.

[0094] The second sealing step is a step of performing focused heating and pressing on the unsealed portion 24a of the first stepped portion, and the unsealed portion 24a of the first stepped portion includes the first stepped portion 31 that was not sealed in the first sealing step.

[0095] The stepped portion special seal portion 23 formed in the second sealing step is located within the area of the side seal portion 22 to be sealed later, and is an area that includes the unsealed portion 24a of the first stepped portion that was not sealed in the first sealing step.

[0096] The heating temperature in the second sealing step is not particularly limited. For performing focused sealing, a temperature below the melting point of the polyester resin of the heat - adhesive layer and higher than the first sealing step is preferred. For example, it is 150°C or higher, preferably 170°C or higher, more preferably 200°C or higher, and for example, 240°C or lower, preferably 230°C or lower.

[0097] To prevent the formation of an unsealed portion that was not sealed in both the first sealing step and the second sealing step due to misalignment of the sealing position, it is preferred that the stepped portion special seal portion 23 formed in the second sealing step partially overlaps with the bottom surface seal portion 21 in the first sealing step.

[0098] The shape and size of the stepped portion special seal portion 23 formed in the second sealing step are not particularly limited, as long as sufficient heating and pressing can be performed on both the two - layer portion TL and the four - layer portion FL near the first stepped portion 31, the unsealed portion 24a of the first stepped portion including the first stepped portion 31 formed in the first sealing step can be firmly joined, and it can be accommodated within the area of the side seal portion 22 to be sealed later. For example, a quadrilateral, oval, etc. having the same width dimension as the side seal portion 22 to be sealed later and a height of about 10 mm to 30 mm in the up - down direction is preferred. The sealing member used in the second sealing step is suitable for this sealing shape.

[0099] Cooling is not performed after the second sealing step. Thereafter, in the third sealing step of forming the side seal portion 22 in such a manner as to include the stepped special seal portion 23 formed in the second sealing step, cooling is performed after heating and pressurization. Since cooling is not performed after the second sealing step, in the region of the stepped special seal portion 23 formed by forming the first stepped unsealed portion 24a in the first sealing step and performing sealing in the second sealing step, even after the second sealing step, an increase in the crystallinity of the polyester resin of the heat-adhesive layer can be suppressed.

[0100] In addition, since the second stepped portion 32 resulting from the cut portions 13 formed on both side portions of the film 12 for forming the bottom surface portion is not in communication with the content accommodating portion, a firm seal is not required, and sealing in the second sealing step is not necessary, but sealing may be performed.

[0101] (Third Sealing Step) Figure 8 Fig. (a) is a schematic view of the third sealing step performed after the second sealing step. Figure 8 (b) is Figure 8 an enlarged view of the circular surrounding portion of (a).

[0102] The third sealing step is a step of performing sealing at positions on both side portions of the self-standing packaging bag SPB to form the side seal portion 22. In the third sealing step, by heating and pressurizing the region including the stepped special seal portion 23 formed in the second sealing step and then cooling, the side seal portion 22 can be formed.

[0103] The heating temperature in the third sealing step is not particularly limited. For example, it is 150°C or higher, preferably 170°C or higher, more preferably 180°C or higher, and for example, it is 230°C or lower, preferably 220°C or lower, more preferably 210°C or lower.

[0104] The shape and size of the side seal portion 22 formed in the third sealing step are not particularly limited as long as the two side portions of the self-standing packaging bag SPB can be effectively sealed. It is generally a linear shape extending from the upper end to the lower end in the vertical direction of the self-standing packaging bag SPB, and preferably the width is 5 mm or more and 30 mm or less. The side-forming sealing member used in the third sealing step is suitable for this sealing shape.

[0105] In the third sealing step, by using the side-forming sealing member to perform heating and pressing and then cooling, the stepped portion special sealing portion 23 formed in the second sealing step and the side sealing portion 22 formed in the third sealing step can be firmly sealed. Since on the first stepped unsealed portion 24a, cooling is not interposed between the two sealing steps of the second sealing step and the third sealing step, after two heating and pressing operations are performed and then cooling is performed after the third sealing step, a firm stepped portion special sealing portion 23 can be formed after the third sealing step.

[0106] (Cutting step) In the present embodiment, by the following cutting step, cutting is performed along the cutting line 15 so as to form individual self-standing packaging bags SPB, and then Figure 1 the self-standing packaging bags SPB shown can be obtained. After filling the content through the upper opening portion Ap of the obtained self-standing packaging bag SPB, by sealing the upper opening portion Ap, a self-standing package can be obtained.

[0107] The manufacturing method of the self-standing packaging bag according to the present embodiment is not limited to the manufacturing method in which the stepped portion special sealing portion 23 is heated and pressed and sealed in the second sealing step, and the side sealing portion 22 is heated and pressed and sealed in the third sealing step and then cooled.

[0108] For example, it can also be a manufacturing method in which the side sealing portion 22 is heated and pressed in the second sealing step without cooling, and the stepped portion special sealing portion 23 is heated and pressed and sealed in the third sealing step and then the area of the side sealing portion 22 is cooled.

[0109] As described above, the manufacturing method of the self-standing packaging bag in the present embodiment can surely perform the sealing near the first stepped portion 31 based on the overlapping of the films even when using a film composed of a hot melt layer containing a polyester resin, and the non-crystalline portion is contained in the polyester resin. The appearance of the first stepped portion 31 of the self-standing packaging bag manufactured by this manufacturing method is excellent, and leakage of the content can be prevented after filling the content.

[0110] In addition, the manufacturing method of the self-standing packaging bag according to the present invention uses a bag-making machine having a set of sealing jigs that are cooled after heating and pressing. The manufacturing method of the self-standing packaging bag according to the present embodiment uses the first set of sealing jigs to perform the heating and pressing and subsequent cooling of the first sealing step, and uses the last second set of sealing jigs to perform the heating and pressing and subsequent cooling of the second and third sealing steps.

[0111] In detail, the first step unsealed portion 24a is formed by using the first set of sealing jigs, and then the first step unsealed portion 24a is heated and pressed in the first sealing process, and then the bottom face seal portion 21 is formed. The first step unsealed portion 24a overlaps with the side seal portion 22 of the self-supporting packaging bag SPB, and the area including a part of the first step 31 is not sealed. As mentioned above, at this moment, the films of the first step unsealed portion 24a are not bonded to each other. The hot adhesive layer of the film used for the self-supporting packaging bag SPB of this embodiment contains a polyester resin in order to prevent the crystallization of the polyester resin at this moment. Since the cooling is performed in the first set of sealing jigs, a strong bottom face seal portion 21 can be formed. Thereafter, the second set of sealing jigs, which is the last one, is used to heat and pressurize the above-mentioned area and the side of the self-supporting packaging bag SPB in the second sealing process and the third sealing process, respectively, and then the cooling is performed to form the step special seal portion 23 and the side seal portion 22. At this point, strong seals can be formed on the bottom seal 21, the step special seal 23 and the side seal 22, so that the first step 31 can be fully and effectively sealed, and the first step 31 has an excellent appearance. Moreover, when it becomes a self-supporting packaging bag SPB, even if it is filled with contents, leakage of the contents can be prevented.

[0112] As described above, the method for manufacturing a self-supporting packaging bag according to the present embodiment can perform sealing by intentionally avoiding the step portion based on the overlap of the films by using the first set of sealing jigs that heat, pressurize, and cool below the melting point of the polyester resin, even when using a film composed of a heat-adhesive layer containing a polyester resin, wherein the polyester resin contains an amorphous portion. Thereafter, by using the second set of sealing jigs that heat, pressurize, and cool for the final time, the area including the step portion that has not been sealed by the first set of sealing jigs is sealed, thereby reliably performing bonding on the step portion and suppressing sealing defects that may cause leakage of the contents from the self-supporting packaging bag.

[0113] Furthermore, since the method for manufacturing the self-supporting packaging bag involved in the present embodiment does not require the additional installation of the ultrasonic sealing mechanism and the high-frequency induction sealing mechanism described in Patent Document 3, etc., it is beneficial in terms of the cost and maintenance of the bag-making device, and can prevent the extremely thin-walled portion caused by the ultrasonic sealing and the high-frequency induction sealing from weakening the strength, or the resin of the hot-melt layer of the thin-walled portion from melting and flowing into the content storage portion to form a resin block. Furthermore, since no sealing marks caused by the ultrasonic sealing and the high-frequency induction sealing are produced, the appearance of the manufactured self-supporting packaging bag SPB is also good.

[0114] [Sealing parts] The sealing member involved in the present invention is a heat-sealing die for forming the bottom surface sealing portion used in the first sealing process in the manufacturing method of a self-standing packaging bag, and it is a sealing member for forming the bottom surface. As described in detail above, the sealing member involved in the present invention is configured in a shape with a cutout portion so that at least a part of the stepped portion based on the overlap of the films is not sealed.

[0115] Figure 9 This is the sealing member for forming the bottom surface, which is a sealing member 41 for forming the bottom surface according to an embodiment of the present invention, and it is in Figure 1 A schematic diagram of the sealing member for forming the bottom surface sealing portion used in the manufacture of the self-standing packaging bag SPB shown. Figure 9 The sealing member shown is the same as Figure 6 The sealing member 41 for forming the bottom surface of the above-described embodiment shown.

[0116] Figure 10 This is the sealing member related to the prior art, that is, the existing sealing member 51 for forming the bottom surface. It is in Figure 12 A schematic diagram of the sealing member for forming the bottom surface sealing portion used in the manufacture of the existing self-standing packaging bag SPB-C shown.

[0117] As Figure 9 shown, the sealing member 41 for forming the bottom surface of the self-standing packaging bag SPB has a stepped portion cutout 42 at least at the boundary between the two-layer portion TL of the pair of films 11 for forming the flat surface portion and the four-layer portion FL where the folded film 12 for forming the bottom surface portion is sandwiched between the pair of films 11 for forming the flat surface portion, that is, at the position corresponding to the first stepped portion 31 based on the overlap of the films. And when there is a cutout portion 13 provided on the film 12 for forming the bottom surface portion, in the region where the folded film 12 for forming the bottom surface portion is sandwiched between the pair of films 11 for forming the flat surface portion, at the position corresponding to the second stepped portion 32 based on the overlap of the films at the boundary between the two-layer portion TL and the four-layer portion FL, there is a side cutout 43. The two-layer portion TL corresponds to the cutout portions 13 at both ends of the film 12 for forming the bottom surface portion of the pair of films 11 for forming the flat surface portion, and the four-layer portion FL is the four-layer portion FL other than the cutout portion 13 of the film 12 for forming the bottom surface portion. Although in Figure 9 it, the side cutout 43 provided at the position corresponding to the second stepped portion 32 is formed integrally with the stepped portion cutout 42, it can also be formed independently.

[0118] In the present invention, the shape and the like of the stepped portion cutout 42 and the side cutout 43 of the sealing member 41 for forming the bottom surface can be of any shape.

[0119] The size of the stepped cutout portion 42 for the bottom surface forming seal member 41 according to the present invention, which is used to make the region including at least a part of the first stepped portion 31 into the unsealed portion 24a of the first stepped portion, is not particularly limited.

[0120] Preferably Figure 9 For the stepped cutout portion 42 on the bottom surface forming seal member 41 shown, with respect to the width of one side seal portion 22, for example, it is 80% or less, preferably 70% or less, more preferably 50% or less, and for example, 5% or more, preferably 10% or more, more preferably 20% or more is unsealed and becomes the unsealed portion 24a of the first stepped portion.

[0121] In Figure 9 For the bottom surface forming seal member 41 shown, a side cutout portion 43 for forming the unsealed portion 24b of the second stepped portion may also be provided in the region including the second stepped portion 32. When the side cutout portion 43 is provided, preferably with respect to the entire length of the second stepped portion 32, for example, it is 100% or less, preferably 80% or less, more preferably 70% or less, further preferably 50% or less, and for example, 0% or more, preferably 5% or more, more preferably 10% or more, further preferably 20% or more is unsealed and becomes the unsealed portion 24b of the second stepped portion.

[0122] In the present invention, the material constituting the bottom surface forming seal member 41 is not particularly limited as long as it is a material capable of forming a seal by heating and pressing the heat - adhesive layer. For example, metals such as iron, stainless steel, aluminum, aluminum alloy, ceramics, their mixtures, their combinations, etc. can be cited.

[0123] In addition, although Figure 6 、 Figure 9 the bottom surface forming seal member 41 for the self - standing packaging bag shown is used to manufacture one bag at a time, but as shown in Figure 11 for example, the bottom surface forming seal member can also be formed in such a way that 2 bags or more bags can be manufactured with one sealing.

[0124] As described above, although the present invention has been described using the above - mentioned embodiments, the technical scope of the present invention is not limited to the scope described in the above - mentioned embodiments. Without departing from the gist of the invention, various changes or improvements can be made to the above - mentioned embodiments, and the forms after applying such changes or improvements are also included in the technical scope of the present invention. In addition, the above - mentioned embodiments can be appropriately combined. In particular, although the manufacturing method of the self - standing packaging bag using a film containing a polyester resin in the heat - adhesive layer has been described, the heat - adhesive layer of the film may not contain a polyester resin.

Claims

1. A method for manufacturing a self-supporting packaging bag, wherein the self-supporting packaging bag comprises a pair of plane parts and a bottom part folded in half at the bottom into an inverted V shape, has a side sealing part and a bottom part sealing part, and has a step part based on the overlapping of a two-layer part and a four-layer part, wherein the two-layer part is formed by overlapping the pair of plane parts, and the four-layer part is formed by overlapping the pair of plane parts and the bottom part, characterized in that: In the first sealing step, the area including at least a portion of the step portion is heated and pressurized in a state where it becomes an unsealed portion, and then cooled to form the bottom surface sealing portion. After the second sealing step, the unsealed portion is heated, pressurized and cooled to be sealed.

2. The method for manufacturing a self-supporting packaging bag according to claim 1, characterized in that: The pair of planar portions and the bottom surface portion are formed of a film having a heat-adhesive layer containing a polyester resin.

3. A sealing component used in a method for manufacturing a self-supporting packaging bag, wherein the self-supporting packaging bag is composed of a pair of flat portions and a bottom portion folded in half at the bottom into an inverted V shape, has a side sealing portion and a bottom portion sealing portion, and has a step portion based on the overlapping of a two-layer portion and a four-layer portion, wherein the two-layer portion is formed by overlapping the pair of flat portions, and the four-layer portion is formed by overlapping the pair of flat portions and the bottom portion, wherein: The heating sealing mold is used to form the bottom surface sealing portion in the first sealing step so that the region including at least a part of the step portion becomes an unsealed portion.

4. A self-supporting packaging bag, characterized in that: The self-supporting packaging bag is manufactured by the method for manufacturing a self-supporting packaging bag according to claim 1 or 2.

5. A method for manufacturing a self-supporting packaging bag, the self-supporting packaging bag comprising a pair of flat portions and a bottom portion folded in half at the bottom into an inverted V shape, having a side sealing portion and a bottom portion sealing portion, and having a step portion based on the overlapping of a two-layer portion and a four-layer portion, wherein the two-layer portion is formed by overlapping the pair of flat portions, and the four-layer portion is formed by overlapping the pair of flat portions and the bottom portion, A bag making machine having a plurality of sealing clamps for cooling after heating and pressurizing is used, characterized in that: On the step portion, there is an area that is sealed only by the last set of sealing clamps.

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