Abstract:
A method of manufacturing a packaging bag includes steps of: preparing a sheet of rectangular film material; forming a bag body from the sheet of the rectangular film material; preparing a shaping member; preparing and attaching a fastener; forming a vertical sealing portion; forming the bottom surface portion so as to include a lower end seal portion; a triangular folded portion; and a flat surface folding portion; and forming the lower sealing portion so as to include a central sealing portion; and a side sealing portion.

Description:
[0001]    This application is a division of co-pending application Ser. No. 11/499,772, filed on Aug. 7, 2006. The content of which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of The Invention 
         [0003]    The present invention relates to a packaging bag in which a shaping member for keeping a bag shape to a hexahedron shape is disposed inside a bag body. 
         [0004]    2. Related Art 
         [0005]    Conventionally, there is known a packaging bag in which a fastener is attached to an inner surface of an opening portion of a bag body for the purpose of re-sealing the opening portion after once opened. In recent years, to such packaging bag, it is desired as an increased demand to accommodate a content in the packaging bag without deforming or damaging the outer appearance thereof. The applicant of the subject patent application has been studying and developing so as to satisfy such desire and provided technology which was disclosed in the Japanese Patent Laid-open (Unexamined) Publication No. 2001-322187. 
         [0006]    The invention disclosed in the this patent publication relates to a packaging bag provided with a bag body formed of a film material, and a shaping member is disposed inside the bag body to keep the outer appearance of the bag body in shape of hexahedron. In a case of forming such packaging bag, a sheet of film material is bent at its central portion, and both side edge portions of the bent sheet are then bonded. 
         [0007]    Flat surface portions and side surface portions of the packaging bag are formed by applying tensions to the film material forming the bag body by the shaping member disposed therein. On the other hand, an upper portion of the packaging bag is formed by bending, toward the central portion, portions corresponding to the respective flat surface portions in a portion protruding over an upper end portion of the shaping member, folding back, toward a bottom surface side, triangular portions corresponding to the respective side surface portions and sealing the folded portions to the side surface portions. The bottom surface portion of the packaging bag is formed by bending the triangular protruded portions formed on both sides of the bottom surface portion toward the central side of the packaging bag and then sealing the bent portion to the outer side surface of the bottom surface portion. 
         [0008]    The packaging bag disclosed in the above publication has a subject feature of capable of accommodating a content in the bag body without deforming the shape of the content by keeping the outer shape or appearance of the bag body to the hexahedron shape by using the shaping member. 
         [0009]    The applicant has been studied and developed such packaging bag after the disclosure of such invention as in the above publication so as to improve productivity, to improve inner-content protective performance, to reduce possibility of the deformation of the shape, to reduce possibility of breakage of packaging bag and so on. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention was conceived in consideration of the above circumstances and an object of the present invention is to provide a packaging bag having an improved strength and rigidity, so that inner content can be safely protected from deforming or damaging the shape of the packaging bag. 
         [0000]    This and other object can be achieved according to the present invention by providing packaging bag comprising: 
         [0011]    a bag body formed from a sheet of rectangular film material; 
         [0012]    a shaping member for keeping the shape of the bag body so as to provide a hexahedron shape having a pair of opposing flat surface portions, a pair of side surface portions positioned on the both sides of the flat surface portions, an upper surface portion and a bottom surface portion opposing to the upper surface portion; and 
         [0013]    a fastener attached to the upper surface portion to be re-sealable after being once opened, 
         [0014]    the shaping member having flat surface forming portions corresponding to the flat surface portions of the bag body and side surface forming portions corresponding to the side surface portions of the bag body which are positioned alternately adjacently the flat surface forming portions and the side surface forming portions being folded along folding lines disposed in parallel with each other, and both ends forming end edges of the flat surface forming portions of the shaping member and end edges of the side surface forming portions being abutted against each other, 
         [0015]    wherein the bag body is formed such that the shaping member is disposed inside, inner surfaces of both the side edges of the film material are bonded with a constant bonding width portion while the shaping member being folded along the folding lines so as to form a tubular member with an upper extending portion extending over the upper end of the shaping member and a lower extending portion extending over the lower end thereof, the flat surface portions and the side surface portions are formed by arranging the film material along the flat surface forming portions and the side surface forming portions of the shaping member, the upper extending portion of the tubular body is folded to form the upper surface portion and the lower extending portion of the tubular body is folded to form the bottom surface portion, 
         [0016]    a vertical sealing portion formed by bonding side edges of the film material together, at the time of forming the tubular body, so as to extend vertically on one side of the flat surface portion of the packaging bag, 
         [0017]    the bottom surface portion includes: a lower end seal portion formed by sealing a portion of the lower extending portion having a constant width from the lower end thereof; a triangular folded portion surrounded by a reference line and oblique lines, in which a portion of the lower extending portion extending downward from the side surface portion is folded toward a center side of the packaging bag with the reference line corresponding to the lower end of the shaping member, and a reference point corresponding to the lower edge of the lower sewing portion at the central portion in the longitudinal direction of the packaging bag and an apex point corresponding to the lower end of the shaping member at the longitudinal end edges of the extending portion from the side surface portion are connected and folded so as to provide inward a protrude portion; and a flat surface folding portion, in which at the lower extending portion, the lower end of the shaping member extending from the flat surface portion is folded centrally of he packaging bag as a reference line so as to accord with the triangular folded portion, and 
         [0018]    the lower sealing portion includes: a central sealing portion formed by sealing the inner surfaces of portions corresponding to the reference points at the extending portion from the flat surface portion; and a side sealing portion formed by sealing the inner surfaces of portions extending from the side surfaces, the side sealing portion being sealed with respectively opposing portions in the longitudinal direction. 
         [0019]    In such the packaging bag, it may be further desired that the upper surface portion includes: a flat surface folding portion formed by folding the portion of the upper extending portion extending upward from the flat surface portion centrally with the upper end of he shaping member being the reference line; a triangular extending portion formed by folding so that the extending portions extending upward from the side surface portions so as to laterally protrude in form of triangle with the upper end of the shaping member being the reference line; an overlap portion by overlapping the inner surfaces mutually opposing at the time of folding the upper extending portion at the central portion in the longitudinal direction of the packaging bag above the flat surface folding portion and the triangular extending portion; and an upper seal portion sealing the upper end edge of the overlap portion, wherein the overlap portion is folded back on the back surface side of the packaging bag, and the triangular extending portion is formed to be flat by being folded back so as to be overlapped with the outer surfaces of the corresponding side surfaces. 
         [0020]    It is also desirable that vertical sealing portion is disposed on the back surface side of the packaging bag so as to be along one side end edge of the back side surface. 
         [0021]    The shaping member may be preferably formed with a bottom surface forming portion extending from the lower ends of the flat surface portions and being foldable with respect to the flat surface forming portions of the shaping member. 
         [0022]    According to the present invention of the characters mentioned above, at the bottom surface portion of the packaging bag, an overlapped portion formed by folding the film material occupies much area, so that the strength of the bottom surface portion of the packaging bag can be increased, effectively preventing the breaking of the bottom surface portion even if some force is applied to this bottom surface portion, and hence, the outer appearance of the packaging bag can be maintained without being deformed and the inner content can be protected safely. 
         [0023]    The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    In the accompanying drawings: 
           [0025]      FIG. 1  is a perspective view of a packaging bag according to one embodiment of the present invention; 
           [0026]      FIG. 2  is a developed view of the packaging bag before manufacture of the packaging bag of  FIG. 1 ; 
           [0027]      FIG. 3  is a cross sectional view of one example of a fastener attached to the bag body of the packaging bag of  FIG. 1 ; 
           [0028]      FIG. 4  is a perspective view showing a tubular structure formed from a film material by bending a shaping member from the state shown in  FIG. 2 ; 
           [0029]      FIG. 5  is a perspective view showing a bottom portion of the tubular structure of the bag body during the manufacture thereof; 
           [0030]      FIG. 6  is also a perspective view showing a bottom portion of the tubular structure during the manufacture thereof; 
           [0031]      FIG. 7  is an explanatory view showing a state in which the film material is overlapped at the bottom portion after being formed; 
           [0032]      FIG. 8  is an explanatory view showing a state in which the film material is overlapped at the bottom portion of a packaging bag of a conventional structure; 
           [0033]      FIG. 9  is a perspective view of a tubular structure with a completed bottom portion; 
           [0034]      FIG. 10  is a perspective view of the tubular structure showing a formation process of an upper portion thereof; 
           [0035]      FIG. 11  is also a perspective view of the tubular structure showing a formation process of an upper portion thereof; 
           [0036]      FIG. 12  is a developed view showing a packaging bag according to another embodiment of the present invention; and 
           [0037]      FIG. 13  is a view showing one example of a process of attaching a fastener and a shaping member to a film material at the time of mass production of the packaging bags. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0038]    A preferred embodiment of the packaging bag according to the present invention will be described hereunder with reference to the accompanying drawings. Further, it is to be noted that terms “upper”, “lower” and like terms are used herein with reference to the illustrations of the drawings or in a generally usable attitude of the packaging bag. 
         [0039]    With reference to  FIGS. 1 and 2 , the packaging bag  1  is composed of a bag body  2  and a shaping member (shape keeping member)  20  which is disposed inside the bag body  2  and configured to keep the outer shape of the bag body  2  to have a hexahedron shape. The location of the shaping member  20  inside the bag body  2  contributes to maintain the outer shape of the bag body  2  to be a hexahedron shape, so that the packaging bag  1  has a pair of flat surface portions  4  and  5  in the longitudinal direction thereof, a pair of side surface portions  6 ,  6  and a pair of vertical upper and bottom surface portions  7  and  8 . Furthermore, a fastener or fastener member  10  is attached to the upper surface  7  so as to be re-closed or re-sealed after the packaging bag  1  is once opened. 
         [0040]    The opposed paired flat surface portions  4  and  5  are pulled in four directions by the shaping member  20  disposed inside the bag body  2  so as to each provide a rectangular shape. Likely, the opposed paired side surface portions  6 ,  6  are also pulled in four-directions by the shaping member  20  so as to each provide a rectangular shape. Further, one of the flat surface portions is constituted as back surface portion  5 , which is formed with a vertical seal line portion  40  at which inner surfaces of overlap sealing width portions are sealed together. This vertical seal line portion  40  extends vertically of the packaging bag  1  along a boundary line between the back surface portion  5  and the side surface portion  6 . On the other hand, the upper surface portion  7  and the bottom surface portion  8  are formed by folding the film materials  3 , which constitutes the bag body  2 , in predetermined processes. 
         [0041]    The structure of the packaging bag  1  mentioned above will be more easily and clearly understood through an explanation of manufacturing processes of the packaging bag  1 . Hereunder, the structure of the packaging bag  1  will be more clearly described in conjunction with the manufacturing process thereof. 
         [0042]    As shown in  FIG. 2 , the bag body  2  is formed from the rectangular film material  3 , and the shaping member  20  is formed so as to have an outer size or dimension slightly smaller than the outer size or dimension of the film material  3  so as to be capable of being disposed inside the outer edges of the film material  3 . 
         [0043]    The shaping member  20  is formed form a cardboard (thickened paper) or like and has two flat surface forming portions  21  and  22  for shaping the flat surface portions  4  and  5 , and two side surface forming portions  23  and  24  for shaping the side surface portions  6 ,  6 . These flat and side surface forming portions  21 ,  22  and  23 ,  24  are arranged side by side alternately as shown in  FIG. 2  and boundary portions of these respective portions are connected through foldable line portions  25 . These flat surface forming portions  21  and  22  have rectangular outer shapes, respectively, and their lateral widths are longer than vertical dimensions thereof so as to provide longitudinally rectangular shapes. While, the side surface forming portions  23  and  24  are formed so as to provide slightly longitudinally longer rectangular shape. 
         [0044]    The shaping member  20  is further provided, at its flat surface forming portions  21  and  22 , with bottom surface forming portions  26  so as to extend downward from the lower ends thereof. The bottom surface forming portions  26  each has a rectangular shape having a width slightly shorter than the width of the flat surface forming portions  21  and  22 . 
         [0045]    As shown in  FIG. 2 , the shaping member  20  is disposed on one surface side of the film material  3  such that the lateral direction thereof is coincident with the long axis direction of the film member  3 . A portion  31  of the film material  3 , having a predetermined range, extends off from the upper ends of the flat surface forming portions  21 ,  22  and the side surface forming portions  23 ,  24 , and a portion  33  of the film material  3 , having a predetermined range, also extends off from the lower ends of the flat surface forming portion  21 ,  22  and the side surface forming portions  23 ,  24 . 
         [0046]    Moreover, overlap sealing width portions  32  and  34 , each having a predetermined width, are formed along the respective end edges of the upper and lower ends of the film material  3 . Overlap sealing width portions  35  and  36  are also formed so as to extend off from both the side edges of the shaping member  20 . The peripheral edge portion of the shaping member  20  is sealed to the film member  3 . 
         [0047]    The portions  31  and  33  having predetermined ranges of the film member  3  extending off from the upper and lower ends of the shaping member  20  are formed as upper surface portion  7  and bottom surface portion  8 , respectively. Further, hereunder, the portion extending off from the upper end of the shaping member  20  is referred to as upper extending portion  31 , and on the other hand, the portion extending off from the lower end of the shaping member  20  is referred to as lower extending portion  33 . 
         [0048]    The fastener  10  is attached to the upper extending portion  31  of the film member  3  such that central portions  31   a,    31   a  thereof corresponding to the side surface portions  6 ,  6  are connected together at slightly lower portion of the overlap sealing width portion  32  formed to the upper end thereof. This fastener  10  is composed of, as shown in  FIG. 3 , a male faster portion  11  and a female fastener portion  15 , which are engageable with each other, and the fastener  10  is attached to the film member  3  in the engaged state. 
         [0049]    The male fastener portion  11  is composed of a belt-shaped base portion  12  and a protruded rib or bar  13  protruding from one surface of the base portion  12  so as to extend at the central portion in its width direction. The protruded rib  13  has an end portion formed so as to be round in section. On the other hand, the female fastener portion  15  is composed of a base portion  16  and a groove portion  17  formed on one surface side in the central portion in the width direction thereof. 
         [0050]    These male and female fastener portions  11  and  15  are engaged with or disengaged from each other by fitting the round portion of the protruded rib  13  into the groove portion  17  or removing the round portion of the protruded rib  13  from the groove portion  17 .  FIG. 3  shows the state in which the male and female fastener portions  11  and  15  are integrally engaged with each other by fitting the round portion of the protruded rib  13  into the groove portion  17  and the female fastener portion  15  is attached to the film material  3 . 
         [0051]    A tubular structure  50  is formed from the state shown in  FIG. 2  in the following manner. That is, the shaping member  20  is bent at the right angle at folding line portions  25  formed to the boundaries between the flat surface forming portions  21 ,  22  and the side surface forming portions  23 ,  24 , respectively, and the end edges of the flat surface forming portion  22  and the side surface forming portion  23 , constituting both the side edges of the shaping member  20 , are abutted against to each other. In this manner, the tubular structure  50  having the rectangular sectional shape is formed. 
         [0052]    Then, the overlap sealing width portions  35  and  36  are overlapped and sealed together. This state is shown in  FIG. 4 . The sealed portion constitutes a vertical seal portion  40 . As can be seen from  FIG. 4 , the vertical seal portion  40  is formed along the boundary line between the back surface portion  5  of one of the flat surface portions  4  and  5  of the packaging bag  1  and one of the side surface portion  6 . 
         [0053]    Thereafter, the bottom surface portion  8  is formed in the following manner. 
         [0054]    With also reference to  FIG. 2 , reference (base) points P 1  are imaged on the inner edge of the sealing width portion  34  at portions corresponding to the side surface portions  6 ,  6  at the lower extending portion  33 . This reference point P 1  is a point positioned at the central portion in the width direction of the portion corresponding to the side surface portion  6 . Side end points Q 1  are also imaged on the boundary line between the side surface portions  6 ,  6  and the flat surface portions  4  and  5  on the inner edge of the sealing width portions  35  and  36  at the lower end positions of the side surface forming portions  23  and  24  in the lower extending portion  33 . These points P 1  and Q 1  are connected respectively by oblique lines L 1 . 
         [0055]    A flat surface folding portion  60  shown in  FIG. 5  is formed from the tubular structure  50  shown in  FIG. 4  such that the portions corresponding to the flat surface portions  4  ad  5  are folded ad bent toward. the center side with the lower ends of the flat surface forming portions  21  and  22  being reference lines. Furthermore, the portions corresponding to the side surface portions  6  are folded and bent toward the center side with the lower ends of the side surface forming portions  23  and  24  being reference lines. Concerning the portions corresponding to the side surface portions, an isosceles triangular portion surrounded with the reference lines corresponding to the lower ends of the side surface forming portions  23  and  24  and the oblique line L 1  is formed as triangular folded (folding) portion  61 , which will be explained hereunder. Further, concerning the lower extending portion  33 , the overlap sealing width portions  34  of the lower ends thereof are bonded together. 
         [0056]    At this time, with each of the portions  62  between the two reference points P 1 , as shown in  FIG. 5 , the inner surfaces thereof are bonded to the portions corresponding to the flat surface portions  4  and  5 . On the other hand, with each of the portion  63  positioned on both sides of the portions  62  between the two reference points P 1  and on the side of the respective reference points P 1 , the inner surfaces of the portions corresponding to the flat surface portions  4  and  5 , and the inner surfaces of the portions corresponding to the side surface portions  6  are bonded together. The bonding of the portions corresponding to the flat surface portions  4  and  5  and the portions corresponding to the side surface portions  6 ,  6  are performed such that the portion corresponding to the front flat surface portion  4  and the portion corresponding to the back flat surface portion  5 , in their front and rear areas, are bonded with the position  31   a  corresponding to the central portion of each side surface portion being the boundary Thus, the overlap sealing width portion  34  provides substantially “H” shape as shown in  FIG. 5 . 
         [0057]    Thereafter, the oblique line L 1  formed to the portion corresponding to the side surface portion  6  is folded inward of the tubular structure so as to provide convex shape, and then, the triangular portion  65  positioned outside of the oblique line L 1 . is folded back toward the center of the tubular structure  50  as shown with arrows in  FIG. 5 . Then, the triangular folded portion  61  having the isosceles triangular shape formed inside the oblique line L 1  is covered from its outer side by the triangular portion  65 . Furthermore, in the overlap sealing width portion  63  at the triangular portion, longitudinally opposing portions are further sealed. The thus formed “H” shaped sealed overlap portions  62  and  63  constitute the lower end seal portion  41  which can tightly seal the lower portion of the package bag  1 . 
         [0058]    Thereafter, the lower end seal portion  41  is bent to the back surface side of the packaging bag  1  and then bonded to the film material  3 . Accordingly, by folding and then sealing the lower extending portion  33 , the flat bottom portion  8  can be provided as shown in  FIG. 6 . 
         [0059]      FIG. 7  shows an overlapped state of the film material  3  at the bottom surface portion  8  of the packaging bag  1  with oblique lines. Further, for the sake of comparison, a conventional example of such overlapped state of a conventional packaging bag provided with a shaping member  20  is shown in  FIG. 8 . 
         [0060]    As shown in  FIG. 7 , in the bottom surface portion  8  of the packaging bag  1  of the present embodiment, the film material  3  is provided such that the flat surface folding (folded) portion  60  and the triangular folded portion  61  are overlapped at portions near both side portions. In addition, at the central portion in the longitudinal direction, the lower end seal portion  41  is disposed in form of belt extending laterally, and this lower end seal portion  41  and the flat surface folding portion  60  are overlapped. 
         [0061]    Moreover, with the one side surface portion positioned left side in  FIG. 7 , the vertical seal portion  40  is overlapped from the central portion in the longitudinal direction toward the back surface portion  5 . In addition, in the packaging bag  1  of this embodiment, a bottom surface forming portion  26  is provided for the shaping member  20 . On the contrary, with the bottom surface portion  8   a  of the conventional packaging bag, as shown in  FIG. 8 , only the triangular folded portion  61  is overlapped with the flat surface folding portion  60   a.  Moreover, any bottom surface forming portion is not provided for the shaping member  20  as in the present embodiment. 
         [0062]    As mentioned above, in the bottom surface portion  8  of the packaging bag  1  of this embodiment, many overlapped portions of the film material are formed in comparison with the packaging bag of the conventional structure of  FIG. 8 , thus increasing the strength and rigidity thereof. In addition, since the shaping member  20  is provided with the bottom surface forming portion  26 , the strength of the bottom surface portion  8  can be improved and the bottom surface portion of the packaging bag can be protected safely. 
         [0063]    Further, the extending portion  31  is formed to the upper portion of the tubular member  50  as an upper surface portion  7  of the packaging bag  1 . 
         [0064]    Referring back to  FIG. 2 , the reference points P 2  are imaged on positions corresponding to the lower end of the fastener mounting portion at the portions corresponding to the side surface portions  6 ,  6  on the upper extending portion  31 . The reference point P 2  is positioned on the central portion in the width direction of the upper extending portion  31  corresponding to the side surface portion  6 . Next, side end points Q 2  are imaged on the boundary line between the side surface portions  6  and the flat surface portions  4 ,  5  on the inner edges of sealing width portions  35 ,  36  at the upper end portions of the side surface forming portions  23 ,  24  of the upper extending portion  31 . These reference points P 2  and the side end points Q 2  are connected as oblique lines L 2 . 
         [0065]    Then, some portions of the upper extending portion  31 , in a non-formed state as shown in  FIG. 9 , corresponding to the flat surface portions  4 ,  5  are folded and bent toward the center side with the upper ends of the flat surface forming portions  21 ,  22  being reference lines to thereby form flat surface folded portion  70 . 
         [0066]    In this folding operation, a portion upper than the reference point P 2  is folded outward so as to provide a protruded shape with respect to the center of the position corresponding to the side surface portion  6 , thus forming an overlapped portion  73  to the portion on the upper side of the reference point P 2 . In this operation, portions corresponding to the side surface portions  6  are folded outward with the upper ends of the side surface forming portions  23 ,  24  being the reference lines, the oblique lines L 2  are folded outward so as to provide the protruded shape, and the isosceles triangular portion is formed on the inside of the oblique lines L 2  as a triangular extending portion  71 . An overlapped portion  73  on the upper side over the reference point P 2  is sealed.  FIG. 10  shows the state of the tubular member  50  after the overlapped portion  73  on the upper side of the reference point P 2  has been sealed. 
         [0067]    Further, in the state shown in  FIG. 10 , the overlap sealing width portion  32  forming the upper end of the overlapped portion  73  is tightly sealed as the upper seal portion  42  and seals the upper portion of the packaging bag  1 . Further, at the lower portion of the upper seal portion  42 , the film material  3  is not sealed and separated. At the fastener attaching portion, the base portion  12  of the male fastener portion  11  is sealed to the inner surface of the back surface portion  5 . 
         [0068]    Thereafter, as shown in  FIG. 11 , the overlapped portion  73  is folded toward the back surface side of the packaging bag  1  in a state that the triangular extending portions  71  are extended outside the packaging bag  1 . The overlapped portion  73  and the triangular extending portion  71  extending outward of the side surfaces  6  of the packaging bag  1  are bent and folded downward of the packaging bag  1  at the upper end portions of the side surface forming portions  23 ,  24 , and then bonded to the outer surfaces of the corresponding side surface portions  6 , thereby forming and completing the packaging bag  1  having hexahedron shape shown in  FIG. 1 . 
         [0069]    Further, although in the packaging bag  1  of the structure mentioned above, the shaping member  20  provided with the bottom surface forming portion  26  was described, the packaging bag  1  may be formed without such bottom surface forming portion  26  of the shaping member  20 . 
         [0070]      FIG. 12  is a developed view of a packaging bag formed by using a shaping member  20   a  provided with no bottom surface forming portion. 
         [0071]    In a packaging bag  1   a  shown in  FIG. 12 , the shaping member  20   a  is not provided with a bottom surface forming portion, and a shaping member having a rectangular outer shape is adopted as the shaping member  20   a.    
         [0072]    The packaging bag  1   a  of this example has a bag body  2  formed from the film material  3 , and the shaping member  20   a  is formed so as to have an outer shape smaller than the outer edge of the film material  3  so that the shaping member  20   a  can be accommodated inside the outer edge of the film material  3 . 
         [0073]    The shaping member  20   a  is composed of two flat surface forming portions  21 ,  22  forming the flat surface portions  4 ,  5  and two side surface forming portions  23 ,  23  forming the side surfaces  6 ,  6 . These flat surface forming portions  21 ,  22  and the side surface forming portions  23 ,  24  are alternately arranged in the developed state, and folding (folded) lines  25  for folding the shaping member  20   a  are formed to boundary lines between the respective these surface forming portions. 
         [0074]    Moreover, a portion of the film material  3  extending from the upper end of the shaping member  20   a  forms the upper extending portion  31 , and a portion of the film material  3  extending from the lower end of the shaping member  20   a  forms the lower extending portion  33 . The film material  3  are formed, at its outer peripheral edge portion, with overlap sealing width portions  32 ,  34 ,  35  and  36 , and a fastener attaching portion  37  to which the fastener  10  is attached is formed to a portion slightly downward of the overlap sealing width portion  32 . 
         [0075]    On the lower extending portion  33 , there is formed an oblique line L 1  connecting the reference point P 1  and the side end points Q 1 , in which the reference point P 1  is a point imaged on the inner edge of the overlap sealing width portion  34  and the side end points Q 1  are points imaged on the boundary line, on the inner edges of the overlap sealing width portions  35 ,  36 , between the flat surface portions  4 ,  5  and the side surface portions  6 ,  6 . 
         [0076]    On the upper extending portion  31 , there is also formed an oblique line L 2  connecting the reference point P 2  and the side end points Q 2 , in which the reference point P 2  is a point imaged on the portion corresponding to the side surface portion at the position corresponding to the lower end of the fastener attaching position and the side end points Q 2  are points imaged on the boundary line, on the inner edges of the overlap sealing width portions  35 ,  36 , between the flat surface portions  4 ,  5  and the side surface portions  6 ,  6 . 
         [0077]    The material developed as shown in  FIG. 12  is also formed into the packaging bag having a hexahedron shape through the steps mentioned above in connection with the former embodiment. 
         [0078]    Further, in a case when it is required to manufacture a lot of such packaging bags, a belt-shaped film material is utilized, which is delivered to which fasteners and shaping members are respectively arranged. 
         [0079]      FIG. 13  represents this film material feeding and delivering step. 
         [0080]    With reference to  FIG. 13 , a belt-shaped film material  81  is fed from a film material roll  80 , and the fasteners  10  are attached thereto with predetermined interval in the longitudinal direction thereof. Each of the fasteners  10  is composed of the male fastener member  11  and the female fastener member  15 , as shown in  FIG. 3 , which are engaged with each other, and is attached to the film material  81  so that the axial direction of the fastener  10  accords with the width direction of the film material  81 . 
         [0081]    Then, the shaping members  20   a  are subsequently arranged on the upstream side of the fasteners  10 , respectively, on the film material  81  in the delivering direction thereof so that the shaping member  20   a  is separated from the fastener  10  with a predetermined distance and the longitudinal direction of the shaping member  81  accords with the with direction of the film material  10 . The shaping member  20   a  is bonded to the film material  81  at its peripheral portions. 
         [0082]    Thereafter, the film material  81  is cut sequentially at cut lines C positioned on the upstream side of each of the fasteners  10  as shown with two-dot-chain lines. Each cut film material corresponds to that shown in  FIG. 12  as a developed view of the packaging bag  1   a . From this state, the packaging bags can be manufactured one by one through the steps mentioned hereinbefore. 
         [0083]    Further, in the example of  FIG. 13 , the shaping member  20   a  is not provided with a bottom surface forming portion, but if the shaping member  20   a  provided with the bottom surface forming portion is utilized, the packaging bag having the structure of the developed view of  FIG. 2  will be manufactured. 
         [0084]    Furthermore, in the above embodiment, the fastener tape is utilized as fasteners  10 , but injection process may be also adapted for fastener forming process. 
         [0085]    Still furthermore, it is to be noted that the present invention is not limited to the described embodiment and many other changes and modifications may be made without departing from the scopes of he appended claims.