Packaging bag and tear guide line forming method

Abstract

To provide a packaging bag that can be unsealed by appropriately tearing along tear-guide lines respectively formed on main and back, two films.SOLUTION: A packaging bag comprises a first film 100a that includes a first tear-guide line 10 having a first straight portion 111 and a smooth-curve portion 112 having a first connection-curve portion and a main curve portion, and a second film 100b that includes a second tear-guide line 20 having straight portions 211, 212, 213 that extend overlapping with the first straight portion 111 of the first tear-guide line 10 instead of overlapping with the curve portion 112. The first tear-guide line 10 is formed, at a first particular region 112a from a first predetermined point P1 to a second predetermined point P2, with a lined groove deeper than a linear groove of a first ordinary region. In its straight portion, the second tear-guide line 20 is formed, at a second particular region 212a corresponding to the first particular region 112a, with a linear groove deeper than a linear groove of a second ordinary region corresponding to the first ordinary region.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a packaging bag having easy-to-open properties and a method for forming a tear guide line in the packaging bag. [Background technology]

[0002] Conventionally, a packaging bag (easy-open, easy-open packaging bag) described in Patent Document 1 is known. In this packaging bag, easy-open lines LA and LB (tear-guiding weakening lines) are formed on each of laminated sheet 1A (first film) and laminated sheet 1B (second film) constituting the front and back of the bag. The easy-open lines LA and LB have overlapping parts (single line (m), single line (M)) that overlap with each other in the same region extending in the tearing direction, and separated parts (branch lines (n1, n2), single line (M)) that do not overlap with each other in the same region extending in the tearing direction (see FIG. 1 of Patent Document 1).

[0003] In such a packaging bag, the tearing of the packaging bag (laminate sheet 1A, laminate sheet 1B) starting from the notch proceeds while being guided by the easy-open lines LA, LB, and the laminate sheet 1A and the laminate sheet 1B are torn and opened (easy opening). Also, in this packaging bag, the easy-open lines A, B formed on the front and back sides of the packaging bag (laminate sheets 1A, 1B) have separation parts (branch lines (n1, n2), single line (M)) where they do not overlap with each other, so that when the packaging bag is torn and opened along the easy-open lines LA, LB, the cut edge lines of the opening part of the packaging bag are shifted up and down at the separation parts. Therefore, the opening part of the packaging bag can be easily opened by pinching the shifted parts. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-112356 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the packaging bag having the above-mentioned structure, the tearing starting from the notch proceeds along the easy-open line LA in one laminate sheet 1A, and along the easy-open line LB in the other laminate sheet 1B. The easy-open line LA of the laminate sheet 1A and the easy-open line LB of the laminate sheet 1B do not overlap over the entire width of the packaging bag, but are separated in the approximate center of the packaging bag. Therefore, in the separated portion, the tearing direction along the two easy-open lines LA and LB is different, and the tearing along the easy-open line LA of the laminate sheet 1A and the tearing along the easy-open line LB of the laminate sheet 1B affect each other. As a result, the tearing of the laminate sheet 1A (or the laminate sheet 1B) may deviate from the easy-open line LA (or the easy-open line LB), making it impossible to properly open the packaging bag.

[0006] The present invention has been made in consideration of these circumstances, and provides a packaging bag that can be opened by properly tearing along tear guide lines (easy-open lines) formed on each of the two films (sheets) on the front and back. [Means for solving the problem]

[0007] The packaging bag according to the present invention is a packaging bag in which a first film and a second film are joined at their peripheral portions to form a bag shape, a tear initiation portion is formed at a first joint portion formed by joining the peripheral portions of the first film and the second film, a first tear guide line for guiding tearing from the tear initiation portion is formed in the first film, and a second tear guide line for guiding tearing from the tear initiation portion is formed in the second film, the first tear guide line having a first straight portion extending from the tear initiation portion in a direction away from the first joint portion and a curved portion continuing from the first straight portion and extending in a curved manner, the second tear guide line overlapping the first straight portion of the first tear guide line and separating from the curved portion without overlapping the curved portion. The first tear guiding wire has a straight portion extending from the first tear guiding wire, and in the first tear guiding wire, the curved portion has a first connecting curved portion that continues smoothly from the first straight portion and a main curved portion that continues smoothly from the first connecting curved portion and curves in the opposite direction to the curved direction of the first connecting curved portion, and a first special region including a boundary point between the first straight portion and the first connecting curved portion is formed with a linear groove that is deeper and / or thicker than the linear groove of a first ordinary region that extends from a tear initiation portion to the first special region, and in the second tear guiding wire, a second special region that corresponds to the first special region of the first tear guiding wire in the tearing direction is formed with a linear groove that is deeper and / or thicker than the linear groove of a second ordinary region that corresponds to the first ordinary region of the first tear guiding wire in the tearing direction.

[0008] With this configuration, in the first tear guide line (first straight portion, curved portion), the first special region (including the boundary point between the first straight portion and the first connecting curved portion of the curved portion) continuing from the first normal region is easier to tear than the first normal region continuing from the tear start portion. The tearing proceeds smoothly from the first straight portion to the first connecting curved portion of the curved portion. In addition, in the second tear guide line (straight portion), the second special region continuing from the second normal region and corresponding to the first special region of the first tear guide line in the tear direction is easier to tear than the second normal region corresponding to the first normal region of the first tear guide line in the tear direction.

[0009] When the tear induced by the first tear guide line in the first film transitions from the first straight portion to the curved portion, the tear direction in the first film and the tear direction induced by the straight portion of the second tear guide line in the second film diverge. When the tear direction in the first film and the tear direction in the second film diverge, the tear in the curved portion of the first film progresses smoothly, and the two tears in the first film and the second film progress through the first special region and the second special region, which are easier to tear.

[0010] In the packaging bag according to the present invention, in the curved portion, radius of curvature is the main curved portion Smaller than the radius of curvature , the configuration may be as follows.

[0011] In addition, in the packaging bag of the present invention, the first special region in the first tear guide line can be configured to be a region from a first predetermined point, at which the distance to the boundary point with the first connecting curved portion is smaller than the distance to the center point of the first straight portion, to a second predetermined point, at which the distance to the boundary point with the first straight portion is smaller than the distance to the center point of the curved portion.

[0012] With this configuration, the length of the deeper and / or thicker first special region in the first tear guide line is less than half the length of the first straight portion and the curved portion that follows it to the center point, which prevents any significant loss in the drop strength, design, and processing time of the packaging bag.

[0013] In the packaging bag according to the present invention, the first predetermined point on the first tear guide line may be a boundary point between the first straight portion and the first connecting curved portion.

[0014] With this configuration, the length from the first specified point to the boundary point between the first straight portion and the first connecting curved portion is essentially zero, and the deeper and / or thicker first special region is further reduced, resulting in more favorable drop strength, design, and processing time for the packaging bag.

[0015] In the packaging bag according to the present invention, the first tear guide line has a second straight portion continuing from the curved portion and extending to a second joint portion opposite to the first joint portion, the straight portion of the second tear guide line overlaps with the second straight portion of the first tear guide line and extends to the second joint portion, the curved portion of the first tear guide line has a second connecting curved portion smoothly continuing from the main curved portion to the second straight portion, and a third special region including a boundary point between the second straight portion and the second connecting curved portion is located at the second straight portion. The first The second tear guide wire is formed with a linear groove that is deeper and / or thicker than the linear groove of the third ordinary region extending from the end point on the second joint side to the third special region, and in the second tear guide wire, a fourth special region corresponding in the tearing direction to the third special region of the first tear guide wire is formed with a linear groove that is deeper and / or thicker than the linear groove of the corresponding fourth ordinary region in the tearing direction of the third ordinary region of the first tear guide wire.

[0016] With this configuration, in the first tear guide wire (first straight portion, curved portion, second straight portion), the third special region (including the boundary point between the curved portion and the second straight portion) continuing from the third ordinary region is easier to tear than the third ordinary region leading to the end point of the second straight portion on the second joint side. The tearing proceeds smoothly from the second connecting curved portion of the curved portion to the second straight portion. In addition, in the second tear guide wire (straight portion), the fourth special region continuing from the fourth ordinary region and corresponding to the third special region of the first tear guide wire in the tearing direction is easier to tear than the fourth ordinary region corresponding to the third ordinary region of the first tear guide wire in the tearing direction.

[0017] When the tear induced by the first tear guide line in the first film moves from the curved portion to the second straight portion, the tear direction in the first film that was separated coincides with the tear direction induced by the straight portion of the second tear guide line in the second film. When the tear direction in the first film that was separated coincides with the tear direction in the second film, the tear in the curved portion of the first film progresses smoothly, and the two tears in the first film and the second film progress through the third and fourth special regions that are easier to tear.

[0018] In the packaging bag according to the present invention, radius of curvature is the main curved portion Smaller than the radius of curvature , the configuration may be as follows.

[0019] In the packaging bag according to the present invention, the third special region of the first tear guide line is closer to the second connecting curved portion than the distance to the center point of the second straight line portion. minutes The region may be configured to extend from a third predetermined point, at which the distance to the boundary point with the second straight line portion is smaller, to a fourth predetermined point, at which the distance to the boundary point with the second straight line portion is smaller than the distance to the center point of the curved portion.

[0020] With this configuration, the length of the deeper and / or thicker third special region in the first tear guide line is less than half the length of the second straight portion and the curved portion that follows it to the center point, which prevents any significant loss in the drop strength, design, and processing time of the packaging bag.

[0021] In the packaging bag according to the present invention, the third predetermined point of the first tear guide line may be a boundary point between the second straight portion and the second connecting curved portion.

[0022] With this configuration, the length from the third specified point to the boundary point between the second straight portion and the second connecting curved portion is essentially zero, and the deeper and / or thicker third special region is further reduced, resulting in more favorable drop strength, design, and processing time for the packaging bag.

[0023] In the packaging bag of the present invention, in the first tear guide line, the area between the first special area and the third special area in the curved portion is formed with a linear groove that is shallower and / or thinner than the linear grooves of the first special area and the third special area, and in the second tear guide line, the area corresponding in the tear direction to the area between the first special area and the third special area of ​​the first tear guide line is formed with a linear groove that is shallower and / or thinner than the linear grooves of the second special area and the fourth special area.

[0024] With this configuration, the area formed by shallower and / or deeper linear grooves in the curved portion is wider, thereby preventing significant impairment of the drop strength, design, and processing time of the packaging bag.

[0025] In the packaging bag of the present invention, each of the first film and the second film can be formed of a surface layer, an inner layer, and an intermediate layer located between the surface layer and the inner layer, and the linear grooves of the first special area, the second special area, the third special area, and the fourth special area can be configured to be deeper than half the depth of the intermediate layer.

[0026] With this configuration, the first special area, the second special area, the third special area, and the fourth special area, which are to become relatively deep linear grooves, can be formed relatively easily.

[0027] In addition, the packaging bag according to the present invention can be configured so that the thickness of the inner surface layer is not less than 100 μm.

[0028] In packaging bags using a film with a layered structure in which the thickness of the inner layer, which greatly affects the thickness of the film, is not less than 100 μm, good tear-opening characteristics can be obtained by partially configuring the first tear guide line and the second tear guide line as deep and / or thick linear grooves.

[0029] In the packaging bag of the present invention, the first tear guide line has an auxiliary guide line that surrounds the tear start portion and intersects with the first straight portion, a predetermined region of the auxiliary guide line including the intersection with the first straight portion is formed with a linear groove that is deeper and / or thicker than the linear grooves of other regions, and the second tear guide line has an auxiliary guide line that surrounds the tear start portion and intersects with the straight portion and overlaps with the auxiliary guide line on the first tear guide line side, and a predetermined region of the auxiliary guide line including the intersection with the straight portion is formed with a linear groove that is deeper and / or thicker than the linear grooves of other regions.

[0030] According to this configuration, even if the tearing of the packaging bag (first film, second film) starting from the tearing initiation portion deviates from the first straight portion of the first tearing guide line on the first film side, when it reaches the auxiliary guide line, it proceeds along the auxiliary guide line, reliably returns to the first straight portion from the predetermined region of the deep and thick linear grooves, and then proceeds while being guided to the first straight portion. Even if the tearing of the second film deviates from the straight portion of the second tearing guide line as the tearing on the first film side deviates from the first straight portion of the first tearing guide line, when it reaches the auxiliary guide line, it proceeds along the auxiliary guide line, reliably returns to the straight portion from the predetermined region of the deep and thick linear grooves, and then proceeds while being guided to the straight portion.

[0031] The tear guide line forming method according to the present invention is a method for forming a tear guide line of the above-mentioned packaging bag, and when forming the first tear guide line in the first film, a laser beam is irradiated to the first normal portion of the first straight portion. region a first step of forming a linear groove from the first special area to the first special area; and a second step of irradiating a laser beam to form a linear groove from the first special area to the third special area. anotherThe method can be configured to include a second step of forming a linear groove from the third special area to the third ordinary area of ​​the second straight portion, and a third step of irradiating laser light to form a linear groove from the third special area to the third ordinary area of ​​the second straight portion.

[0032] According to this configuration, when forming the first tear guiding line in the first film, the first special area and the third special area can be formed by overlapping the irradiated laser light, so that the first special area and the third special area can be easily formed as deep linear grooves. In addition, when overlapping, the return amount of the laser light (corresponding to the length of each of the first special area and the third special area) can be reduced, so that the linear groove of the first tear guiding line can be efficiently formed.

[0033] The tear guide line forming method of the present invention is a method for forming a tear guide line in the above-mentioned packaging bag, and when forming the second tear guide line in the second film, the method includes a first step of irradiating a laser beam to form a linear groove from the second normal region to the second special region of the straight portion, a second step of irradiating a laser beam to form a linear groove from the second special region to the fourth special region of the straight portion, and a third step of irradiating a laser beam to form a linear groove from the fourth special region to the fourth normal region of the straight portion.

[0034] With this configuration, when forming the second tear guiding line in the second film, the second special area and the fourth special area can be formed by overlapping the irradiated laser light, so that the second special area and the fourth special area can be easily formed as deep linear grooves. In addition, when overlapping, the return amount of the laser light (corresponding to the length of each of the second special area and the fourth special area) can be reduced, so that the linear groove of the second tear guiding line can be efficiently formed. Effect of the Invention

[0035] According to the packaging bag of the present invention, in the process in which the first film and the second film are torn while being guided by the first tear guide line and the second tear guide line from the tear start part, when the tear direction of the first film and the tear direction of the second film are separated, the tear proceeds smoothly from the first straight part to the first connecting curved part of the curved part, and the two tears of the first film and the second film proceed through the first special area and the second special area which are easier to tear. Therefore, when the tear direction of the first film and the tear direction of the second film are separated, the tear of the first film (or the second film) is not easily influenced by the tear of the second film (or the first film), and is less likely to deviate from the first tear guide line (or the second tear guide line). Therefore, the bag can be opened by properly tearing along the tear guide lines formed on each of the two front and back films.

[0036] In addition, according to the packaging bag of the present invention (claim 5), when the tear direction induced by the curved portion of the first tear guide line in the separated first film coincides with the tear direction induced by the straight portion of the second tear guide line in the second film, the tear proceeds smoothly from the second connecting curved portion of the curved portion to the second straight portion, and the two tears in the first film and the second film proceed through the third special area and the fourth special area, which are easier to tear. Therefore, when the tear direction in the first film coincides with the tear direction in the second film, the tear in the first film (or the second film) is not easily influenced by the tear in the second film (or the first film), and is less likely to deviate from the first tear guide line (or the second tear guide line). Therefore, the bag can be opened by properly tearing along the tear guide lines formed on each of the two front and back films. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a front view showing a main part of a packaging bag according to an embodiment of the present invention. [Diagram 2]FIG. 2 is a cross-sectional view showing an example of the layer structure of each of the front film (first film) and the back film (second film) constituting the packaging bag shown in FIG. [Diagram 3] FIG. 3 is an enlarged view showing a detailed shape of a curved portion of a main guide wire in the first tear guide wire. [Figure 4] FIG. 4 is an enlarged view showing a first tear guide line and a second tear guide line formed in the packaging bag shown in FIG. [Figure 5A] FIG. 5A is an enlarged view of a first special region in the first tear guide wire. [Figure 5B] FIG. 5B is an enlarged view of the third special region in the first tearing guide wire. [Figure 6A] FIG. 6A is a diagram showing a method for forming a main guide wire of the first tear guide wire. [Figure 6B] FIG. 6B is a diagram showing a main guide wire of the first tear guide wire formed by the method shown in FIG. 6A. [Figure 7A] FIG. 7A is a diagram showing a method for forming a main guide wire of a second tear guide wire. [Figure 7B] FIG. 7B is a diagram showing a main guide wire of the second tear guide wire formed in the manner shown in FIG. 7A. [Figure 8] FIG. 8 is a cross-sectional view showing the cross-sectional shapes of the first tearing guide line and the second tearing guide line (linear groove) formed by one laser irradiation. [Figure 9] FIG. 9 is a cross-sectional view showing the cross-sectional shapes of the first tearing guide line and the second tearing guide line (linear groove) formed by multiple (two) laser irradiations. [Figure 10] FIG. 10 is a diagram showing an example of how the first film and the second film are torn when the packaging bag shown in FIG. 1 is opened. [Figure 11] FIG. 11 is a diagram showing the results of an experiment on tearing of a packaging bag. [Figure 12] FIG. 12 is a diagram showing an opening cut edge of a packaging bag that has been torn open in the manner shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] An embodiment of the present invention will be described with reference to the drawings.

[0039] A packaging bag according to an embodiment of the present invention is configured as shown in FIG.

[0040] In FIG. 1, the packaging bag 100 is, for example, a pouch with a plastic fastener, and a front film 100a (first film) and a back film 100b (second film) are formed into a bag shape by joining the peripheries of each. As shown in FIG. 2, each of the front film 100a and the back film 100b has a structure in which a PET layer 101 (surface layer) made of polyethylene terephthalate, an NY layer 102 (middle layer) made of nylon, which is a polyamide synthetic resin, and a PE layer 103 (inner layer) made of polyethylene are laminated. The PET layer 101 has a high transparency and excellent dimensional stability that is difficult to expand and contract, and is suitable as a printing layer. The NY layer 102 is resistant to impact and bending, and is difficult to open holes, and is a layer for ensuring strength. The PE layer 103 has a property of melting at a temperature of about 100° C. to 130° C., and is a layer serving as a sealant layer suitable for heat welding.

[0041] In this way, the front film 100a and the back film 100b, each having a structure in which the PET layer 101 (front layer) and the PE layer 103 (inner layer) are arranged on the outermost sides of the front and back and the NY layer 102 (middle layer) is arranged on the inside thereof, are formed into a bag shape by heat welding (joining) the PE layers 103 of the respective peripheral portions of the front film 100a and the back film 100b with the respective PE layers 103 facing each other. As a result, a packaging bag 100 is formed, with the PE layer 103 (inner layer) facing on the inside, sealed by the peripheral seal parts (join parts) 16, 17, 18 (the lower seal part opposite the seal part 18 is omitted) as shown in FIG. 1.

[0042] Returning to FIG. 1, the packaging bag 100 is provided with a plastic fastener 19 extending linearly between the two laterally opposing seal portions 16, 17 at a position a predetermined distance below the upper seal portion 18. This plastic fastener 19 has a known structure and can be opened and closed freely. A storage section for contents (e.g., food and drink) is formed on the side opposite the upper seal portion 18, with the plastic fastener 19 as a boundary. After opening, the contents can be removed from the storage section by opening the plastic fastener 19. On the other hand, the storage section in which the contents are stored can be sealed by closing the plastic fastener 19.

[0043] In the case of packaging bag 100 having a gusset portion at the bottom, the upper peripheral portions of front film 100a and back film 100b are sealed with plastic fastener 19 open to accommodate the contents in the accommodation portion, and then plastic fastener 19 is closed to hermetically seal the accommodation portion, forming upper sealed portion 18. In the case of packaging bag 100 being a flat pouch not having a gusset portion, the upper sealed portions 18 of front film 100a and back film 100b are formed, and then the contents are accommodated from the lower peripheral portions, and a lower sealed portion (not shown) is formed.

[0044] 1, a first tear guide line 10 is formed in the front film 100a, and a second tear guide line 20 is formed in the back film 100b. A left notch 15a (tear start portion) is formed in the left sealed portion 16 (first joint portion) of the packaging bag 100. A right notch 15b (tear start portion) is formed in the right sealed portion 17 (second joint portion) of the packaging bag 100 so as to face the left notch 15a. The first tear guide line 10 and the second tear guide line 20 each extend from the outer edge line of the sealed portion 16 to the outer edge line of the opposite sealed portion 17.

[0045] The first tear guide line 10 formed in the front film 100a includes a main guide line 11 extending from the outer edge line of the sealed portion 16 to the outer edge line of the sealed portion 17, a first auxiliary guide line 12a formed to surround the left notch 15a of the sealed portion 16 and the end of the main guide line 11 and intersect with the main guide line 11, and a second auxiliary guide line 12b formed to surround the right notch 15b of the sealed portion 17 and the end of the main guide line 11 and intersect with the main guide line 11. In addition, the second tear guide line 20 formed in the back film 100b includes a main guide line 21 extending in a straight line from the outer edge line of the sealed portion 16 to the outer edge line of the sealed portion 17, a first auxiliary guide line 22a formed to surround the left notch 15a of the sealed portion 16 and the end of the main guide line 21 and intersect with the main guide line 21, and a second auxiliary guide line 22b formed to surround the right notch 15b of the sealed portion 17 and the end of the main guide line 21 and intersect with the main guide line 21.

[0046] Although the left notch 15a and the right notch 15b are formed so as to overlap the ends of the main induction wire 11 and the main induction wire 21 on the front and back sides, there may be cases where the left notch 15a and the main induction wire 11 or the main induction wire 21, or the right notch 15b and the main induction wire 11 or the main induction wire 21 do not overlap accurately due to variations in manufacturing conditions, etc.

[0047] When the packaging bag 100 (front film 100a, back film 100b) is divided approximately evenly into three regions, a first region E1, a second region E2, and a third region E3, in the tearing direction (width direction) starting from the left notch 15a, in the first region E1, the pair of the first auxiliary guide wire 12a and the straight portion 111 (first straight portion) of the main guide wire 11 in the front film 100a and the pair of the first auxiliary guide wire 22a and the straight portion 211 of the main guide wire 21 in the back film 100b have the same shape and overlap each other. In the second region E2, the main guide line 11 of the front film 100a smoothly continues from the straight portion 111 of the first region E1 to a curved portion 112 that curves so as to protrude toward the plastic fastener 19 (to the lower side of the packaging bag 100), while the main guide line 21 of the back film 100b becomes a straight portion 212 that continues directly from the straight portion 211 of the first region E1. Thus, in the second region E2, the main guide line 11 (curved portion 212) in the front film 100a and the main guide line 21 (straight portion 212) in the back film 100b are separated without overlapping. In the third region E3, similarly to the first region E1, the pair of the second auxiliary induction wire 12b and the straight portion 113 (second straight portion) of the main induction wire 11 in the front film 100a and the pair of the second auxiliary induction wire 22b and the straight portion 213 of the main induction wire 21 in the back film 100b have the same shape and overlap each other.

[0048] A more detailed shape of the curved portion 112 of the main guide wire 11 in the first tear guide wire 10 is shown in FIG.

[0049] In FIG. 3, the curved portion 112 smoothly continues from the straight portion 111 and is curved in an arc shape that bulges upward (in the upward direction in FIG. 3) toward the upper seal portion 18 (see FIG. 1) of the packaging bag 100, having a first connecting curved portion 1121, and further smoothly continues from the first connecting curved portion 1121 and has a main curved portion 1120 that is curved in an arc shape in the direction opposite to the bending direction of the first connecting curved portion 1121. The curved portion 112 further smoothly continues from the main curved portion 1120 to a straight portion 113 (second straight portion) and has a second connecting curved portion 1122 that is curved in an arc shape in the direction opposite to the bending direction of the main curved portion 1120. The radius of curvature R2 representing the degree of curvature of each of the first connecting curved portion 1121 and the second connecting curved portion 1122 is smaller than the radius of curvature R1 representing the degree of curvature of the main curved portion 1120 located between these connecting curved portions 1121 and 1122 (R2 < R1: the degree of curvature is large). For example, when the width of the packaging bag 100 (front film 100a and back film 100b) is 160 mm and the width of the curved portion 112 is 53 mm, the radius of curvature R2 of each of the first connecting curved portion 1121 and the second connecting curved portion 1122 is set to 28.5 mm, and the radius of curvature R1 of the main curved portion 1120 is set to 90 mm.

[0050] The curved portion 112 having such a shape in which the first connecting curved portion 1121, the main curved portion 1120, and the second connecting curved portion 1122 are smoothly connected is configured as a gentle curve. Therefore, the first film 100a can be torn along the curved portion 112 with little resistance, and the tearing is less likely to deviate from the curved portion 112.

[0051] Next, the first tear-inducing line 10 including the curved portion 112 having the above-described shape and the second tear-inducing line 20 including the straight portions 211, 212, and 213 are configured in more detail as shown in FIGS. 4, 5A, and 5B.

[0052] In FIG. 4, the main guide wire 11 of the first tear guide wire 10 is composed of a straight portion 111 (first straight portion) extending from the outer edge line of the sealed portion 16, a curved portion 112 (via a first connecting curved portion 1121) extending in a curved manner from the straight portion 111, and a straight portion 113 (second straight portion) extending from the curved portion 112 to the outer edge line of the sealed portion 17. In such a first tearing guide wire 10 (main guide wire 11), as shown in an enlarged view in Fig. 5A, the area from the boundary point P1 itself as the first predetermined point where the distance (substantially zero) between the boundary point with the curved portion 112 (first connecting curved portion 1121: see Fig. 3) and the end of the straight portion 111 overlaps with the end of the curved portion 112 (first connecting curved portion 1121) is smaller than the distance Lc1 between the straight portion 111 and its center point to the second predetermined point P2 of the curved portion 112 is set as the first special area 112a. This first special area 112a is formed by a linear groove deeper than the linear groove of the entire straight portion 111, that is, the first normal area from the left notch 15a of the straight portion 111 (first straight portion) to the first special area 112a (end point P1). 5A, the second predetermined point P2 is determined to be a point where a distance Ls1 to a boundary point P1 with the straight portion 111 is smaller than a distance Ls2 to the center point Po of the curved portion 112. That is, in the curved portion 112, a distance Ls1 (corresponding to the first special region 112a formed as a deep linear groove) between the boundary point P1 with the straight portion 111 (first straight portion) and the second predetermined point P2 is smaller than 1 / 2 of a distance Lo between the boundary point P1 with the straight portion 111 and its center point Po.

[0053] 4, in the straight portion (211, 212, 213) of the second tearing guide wire 20 (main guide wire 21), the area corresponding to the first special area 112a of the first tearing guide wire 10 (main guide wire 11) in the tearing direction Dt from the left notch 15a is set as the second special area 212a. This second special area 212a is formed by a linear groove deeper than the linear groove of the straight portion 211 (second ordinary area) corresponding to the straight portion 111 (first ordinary portion) of the first tearing guide wire 10 (main guide wire 11) in the tearing direction Dt.

[0054] In addition, in the first tearing guide wire 10 (main guide wire 11), as shown in an enlarged view in FIG. 5B, the area from the boundary point P3 itself as a third predetermined point where the distance (effectively zero distance) to the boundary point with the curved portion 112 (second connecting curved portion 1122: see FIG. 3) is smaller than the distance Lc2 to the center point of the straight portion 113 (second straight portion) to the fourth predetermined point P4 of the curved portion 112 is set as the third special area 112b. This third special area 112b is formed from the right notch 15b of the straight portion 113 (second straight portion) to the third special area 112b, that is, a linear groove deeper than the linear groove of the entire straight portion 113. The fourth predetermined point P4 is determined as a point where the distance Ls3 to the boundary point P3 with the straight portion 113 (second straight portion) is smaller than the distance Ls4 to the center point Po of the curved portion 112. That is, in the curved portion 112, the distance Ls3 (corresponding to the third special region 112b formed as a deep linear groove) between the boundary point P3 with the straight portion 113 and the fourth specified point P4 is smaller than 1 / 2 the distance Lo between the boundary point P3 with the straight portion 113 and its center point Po.

[0055] 4, in the straight portion (211, 212, 213) of the second tearing guide wire 20 (main guide wire 21), the area corresponding to the third special area 112b of the first tearing guide wire 10 (main guide wire 11) in the tearing direction Dt is set as the fourth special area 212b. This fourth special area 212b is formed by a linear groove deeper than the linear groove of the straight portion 213 (fourth ordinary area) corresponding to the straight portion 113 (third ordinary area) of the first tearing guide wire 10 (main guide wire 11) in the tearing direction Dt.

[0056] In the first tearing guide wire 10 (main guide wire 11), the region between the first special region 112a and the third special region 112b of the curved portion 112 (the region between the second predetermined point P2 and the fourth predetermined point P4 in FIG. 4) is formed by a linear groove shallower than the linear grooves of the first special region 112a and the third special region 112b, similar to the straight portion 111 (first straight portion: first normal region) and the straight portion 113 (second straight portion: third normal region). In the second tearing guide wire 20 (main guide wire 21), the region between the second special region 212a and the fourth special region 212b (included in the straight portion 212) is formed by a linear groove shallower than the linear grooves of the second special region 212a and the fourth special region 212b, similar to the straight portion 211 (second normal region) and the straight portion 213 (fourth normal portion).

[0057] The main guide line 11 of the first tear guide line 10 described above is formed as a linear groove in the front film 100a by, for example, irradiation with laser light.

[0058] Specifically, as shown in Fig. 6A, the laser beam is irradiated in three separate steps in the order of steps (1), (2), and (3) with partial overlapping, i.e., a first portion 11(1) continuing from a straight line to one end of a curved line, a second portion 11(2) of the curved line, and a third portion 11(3) continuing from the other end of the curved line to a straight line. The overlapping portions (between P1 and P2, between P4 and P3) that are irradiated twice with the laser beam are formed as linear grooves that are deeper than the linear grooves of the other portions that are irradiated only once with the laser beam. As a result, as shown in Figure 6B, the first special region 112a (corresponding to the area between P1 and P2) and the third special region 112b (corresponding to the area between P4 and P3) located at both ends of the curved portion 112 are each formed with a linear groove that is deeper than any of the linear grooves in the straight portion 111 (first straight portion: first normal region), the linear grooves in the straight portion 113 (second straight portion: third normal region), and the linear grooves in the region between the first special region 112a and the third special region 112b of the curved portion 112.

[0059] Similarly, the main guide line 21 of the second tear guide line 20 is also formed as a linear groove in the back film 100b by irradiation with laser light.

[0060] Specifically, as shown in Fig. 7A, the laser irradiation is performed in three separate steps, ie, steps (1), (2), and (3), with partial overlapping, on three straight line portions 21(1), 21(2), and 21(3). In this case, the overlapping portions that are irradiated twice with the laser light are formed as linear grooves that are deeper than the linear grooves of the other portions that are irradiated only once with the laser light. As a result, as shown in Fig. 7B, the second special region 212a and the fourth special region 212b located at both ends of the central straight line portion 212 are formed as linear grooves that are deeper than the linear grooves of the straight line portion 211, the linear grooves of the straight line portion 213, and the linear grooves of the region between the second special region 212a and the fourth special region 212b of the straight line portion 212.

[0061] In the front film 100a and the back film 100b, the linear grooves 110 (corresponding to the straight portions 111, 113, parts of the curved portion 112, the straight portions 211, 213, and parts of the straight portion 212) formed by one irradiation of the laser beam have a depth extending from the PET layer 101 (surface layer) to the NY layer 102 (intermediate layer) as shown in Fig. 8. In the front film 100a and the back film 100b, the linear grooves 120 (the first special region 112a, the second special region 212a, the third special region 112b, and the fourth special region 212b) formed by two irradiations of the laser beam have a depth deeper than half the depth of the NY layer 102 (intermediate layer), for example, a depth extending from the PET layer 101 (surface layer) to the boundary between the NY layer 102 (intermediate layer) and the PE layer 103 (inner layer) as shown in Fig. 9.

[0062] In the first tearing guide wire 10, the first auxiliary guide wire 12a formed to surround the left notch 15a and the end of the main guide wire 11, and the second auxiliary guide wire 12b formed to surround the right notch 15b and the end of the main guide wire 11, each of the predetermined regions 121a, 121b (see FIG. 4) including the intersections with the main guide wire 11 are formed as linear grooves (irradiated twice with laser light) deeper than the linear grooves (irradiated once with laser light) in other regions. In the second tearing guide wire 20, the first auxiliary guide wire 22a formed to surround the left notch 15a and the end of the main guide wire 21, and the second auxiliary guide wire 22b formed to surround the right notch 15b and the end of the main guide wire 21, each of the predetermined regions 221a, 221b (see FIG. 4) including the intersections with the main guide wire 21 are also formed as linear grooves deeper than the linear grooves in other regions.

[0063] The packaging bag 100 having the above-described structure can be opened, for example, as shown in FIG.

[0064] 10, when the packaging bag 100 (front film 100a, back film 100b) starts to be torn from the left notch 15a of the sealed portion 16 toward the opposite sealed portion 17, the tear in the front film 100a in the first region E1 progresses while being guided by the straight portion 111 of the main guide line 11. Even if the tear deviates from the straight portion 111 (main guide line 11), when it reaches the first auxiliary guide line 12a, it proceeds along the first auxiliary guide line 12a and returns reliably to the straight portion 111 of the main guide line 11 from a predetermined region 121a of the deep linear groove (see FIG. 4), and then proceeds while being guided by the straight portion 111. At this time, the tear in the back film 100b similarly progresses while being guided by the straight portion 211 of the main guide line 21, and even if the tear deviates from the straight portion 211 (main guide line 21), it progresses along the first auxiliary guide line 22a and returns reliably to the straight portion 211 from a specified region 221a of the deep linear groove (see Figure 4), and then continues to progress while being guided by the straight portion 211.

[0065] In the first region E1, a set of the straight line portions 111 of the first auxiliary guide wire 12a(10) and the main guide wire 11(10) in the front film 100a and a set of the straight line portions 211 of the first auxiliary guide wire 22a(20) and the main guide wire 21(20) in the back film 100b overlap in the same shape. Therefore, when the packaging bag 100 is torn in the first region E1, the front film 100a and the back film 100b are simultaneously guided by the two overlapping tear guide lines (12a(10), 22a(20), 111, 211) and are torn while overlapping with no deviation of the actual tear lines (see La, Lb in FIG. 10).

[0066] When the tearing of the packaging bag 100 moves from the first region E1 to the second region E2, the tearing of the front film 100a moves from the straight portion 111 of the main guide line 11 (10) to the curved portion 112, and continues while being guided by the curved portion 112. On the other hand, the tearing of the back film 100b continues from the straight portion 211 of the main guide line 21 (20) to the straight portion 212, and continues while being guided by the straight portion 212.

[0067] In the second region E2, the curved portion 112 of the main guide line 11(10) in the front film 100a and the straight portion 212 of the main guide line 21(20) in the back film 100b are separated without overlapping and have different shapes. Therefore, when the packaging bag 100 is torn in the second region E2, the front film 100a and the back film 100b are torn while being guided by two separated tear guide lines that do not overlap (the curved portion 112 of the main guide line 11(10) and the straight portion 212 of the main guide line 21(20)) and the actual tear line (see La, Lb in FIG. 10) is shifted.

[0068] When the tearing of the packaging bag 100 moves from the second region E2 to the third region E3, the tearing of the front film 100a moves from the curved portion 112 to the straight portion 113 of the main guide line 11(10) and proceeds while being guided by the straight portion 113 of the main guide line 11(10). Then, the tearing reaches the outer edge line of the sealed portion 17 while being guided by the straight portion 113 of the main guide line 11(10). Meanwhile, the tearing of the back film 100b also moves from the straight portion 212 of the main guide line 21(20) to the straight portion 213 and proceeds while being guided by the straight portion 213 of the main guide line 21(20). Then, the tearing reaches the outer edge line of the sealed portion 17 while being guided by the straight portion 213 of the main guide line 21(20).

[0069] In the third region E3, similar to the first region E1, the straight portion 113 of the main guide line 11 (10) in the front film 100a and the straight portion 213 of the main guide line 21 (20) in the back film 100b overlap in the same shape (straight line). Therefore, when the packaging bag 100 is torn in the third region E3, the front film 100a and the back film 100b are simultaneously guided by the two overlapping tear guide lines (straight portion 113, straight portion 213) and torn while the actual tear lines (see La, Lb in FIG. 10) overlap without shifting, and the tear reaches the outer edge line of the sealed portion 17 in one go.

[0070] When the packaging bag 100 is torn as described above, the tearing induced by the main guide line 11 of the first tear guide line 10 in the front film 100a moves from the straight line portion 111 (first straight line portion) to the curved portion 112. At that time, the tearing direction in the front film 100a and the tearing direction induced from the straight line portion 211 to the straight line portion 212 in the main guide line 21 of the second tear guide line 20 in the back film 100b are separated. When the tear direction in the front film 100a and the tear direction in the back film 100b diverge, the tear progresses smoothly, guided by the gentle curved portion 112 (first connecting curved portion 1121, main curved portion 1120: see Figure 3) in the front film 100a, while the two tears in the front film 100a and back film 100b progress through the first special region 112a and second special region 212a (see Figure 4), which are formed by deep linear grooves and are easier to tear. Therefore, when the tear direction in the front film 100a and the tear direction in the back film 100b diverge, the tearing of the front film 100a (or the back film 100b) is less likely to be affected by the tearing of the back film 100b (or the front film 100a) and is less likely to deviate from the main guide line 11 of the first tear guide line 10 (or the main guide line 21 of the second tear guide line 20).

[0071] Furthermore, the tear induced by the main guide line 11 of the first tear guide line 10 of the front film 100a proceeds further from the curved portion 112 to the straight portion 113 (second straight portion). At this time, the tear direction of the separated front film 100a coincides with the tear direction induced by the shift from the straight portion 212 to the straight portion 213 of the main guide line 21 of the second tear guide line 20 of the back film 100b. When the tear direction of the front film 100a and the tear direction of the back film 100b coincide with each other, the tear proceeds smoothly, guided by the gentle curved portion 112 (main curved portion 1120, second connecting curved portion 1122: see Figure 3) in the front film 100a, and the two tears in the front film 100a and the back film 100b proceed through the third special region 112b and the fourth special region 212b, which are easier to tear (see Figure 4). Therefore, when the tear direction in the front film 100a and the tear direction in the back film 100b match, the tearing of the front film 100a (or the back film 100b) is less likely to be affected by the tearing of the back film 100b (or the front film 100a) and is less likely to deviate from the main guide line 11 of the first tear guide line 10 (or the main guide line 21 of the second tear guide line 20).

[0072] Therefore, according to the above-mentioned packaging bag 100, even if the main guide line 11 of the first tear guide line 10 formed in the front film 100a and the main guide line 21 of the second tear guide line 20 formed in the back film 100b include portions that do not overlap with each other (curved portion 112, straight portion 212), the packaging bag can be properly torn and opened while being guided without straying from either the first tear guide line 10 (main guide line 11) or the second tear guide line 20 (main guide line 21).

[0073] From the viewpoint of proper tear-opening, it is preferable to form the first tear guide line 10 and the second tear guide line 20 as deep and / or thick linear grooves. However, if the entire tear guide line is formed as a deep and / or thick linear groove, the drop strength is reduced, and the drop strength problem becomes evident especially in the case of a flat pouch without a plastic fastener 19 and with a relatively large capacity. In addition, if the entire tear guide line is formed as a deep and / or thick linear groove, the design of the surface pattern of the packaging bag 100 may be impaired, and the processing time will increase, such as by increasing the number of times of laser light irradiation overall.

[0074] However, in the packaging bag 100 described above, only a portion of the tear guide lines 10, 20 formed in each of the two front and back films 100a, 100b (the first special area 112a, the second special area 212a, the third special area 112b, and the fourth special area 212b) are formed into deep and / or thick linear grooves, so that drop strength, design, and processing time are not significantly compromised.

[0075] An experiment was carried out on the tear-open performance of the following packaging bags 1 to 5. The results are shown in FIG.

[0076] ·Packaging bag 1: 12μm thick PET layer (surface layer) formed with transparent vapor deposition PET 15μm thick NY layer (middle layer) made of nylon 130μm thick PE layer (inner layer) made of linear low density polyethylene (LLDPE) ·Packaging bag 2: 12μm thick PET layer (surface layer) formed with transparent vapor deposition PET 15μm thick NY layer (middle layer) made of nylon 150μm thick PE layer (inner layer) made of linear low density polyethylene (LLDPE) ·Packaging bag 3: 12μm thick PET layer (surface layer) made of PET 12μm thick PET layer (middle layer) made of aluminum-deposited PET 110μm thick PE layer (inner layer) made of linear low density polyethylene (LLDPE) ·Packaging bag 4: 12μm thick PET layer (surface layer) made of PET 15μm thick NY layer (middle layer) made of nylon 7μm thick aluminum layer (inner surface) made of aluminum foil 60μm thick PE layer (inner layer) made of linear low density polyethylene (LLDPE) ·Packaging bag 5: 15μm thick NY layer (surface layer) made of nylon 80μm thick PE layer (inner layer) made of linear low density polyethylene (LLDPE)

[0077] For each of the packaging bags 1, 2, 3, and 5, 10 pieces of the first tear guide line 10 and the second tear guide line 20 were formed by partially irradiating the laser beam twice as shown in the embodiment (hereinafter referred to as curved portion processed twice), and 10 pieces of the tear guide line were formed by irradiating the laser beam once (hereinafter referred to as curved portion processed once), and these were actually torn. In addition, for the packaging bag 4, 160 pieces of the curved portion processed once were prepared, and these were actually torn.

[0078] As a result, as shown in FIG. 11, for the packaging bag 1, 5 out of 10 products with a curved portion processed once were guided by the tear guide line and successfully opened (50% successful opening rate), whereas 9 out of 10 products with a curved portion processed twice were guided by the tear guide line and successfully opened (90% successful opening rate). For the packaging bag 2, 6 out of 10 products with a curved portion processed once were guided by the tear guide line and successfully opened (60% successful opening rate), whereas 9 out of 10 products with a curved portion processed twice were guided by the tear guide line and successfully opened (90% successful opening rate). For the packaging bag 3, 3 out of 10 products with a curved portion processed once were guided by the tear guide line and successfully opened (30% successful opening rate), whereas 9 out of 10 products with a curved portion processed twice were guided by the tear guide line and successfully opened (90% successful opening rate).

[0079] Furthermore, for packaging bags 4, 156 out of 160 bags were able to be opened by being guided by the tear guide line in the products with the curved portion processed once (97.5% successful opening rate). For packaging bags 5, 9 out of 10 bags were able to be opened by being guided by the tear guide line in the products with the curved portion processed once (90% successful opening rate), and 10 out of 10 bags were able to be opened by being guided by the tear guide line in the products with the curved portion processed twice (100% successful opening rate).

[0080] From the above experimental results, it was found that in the packaging bag (see packaging bag 1 to packaging bag 3) in which the main guide line 11 of the first tear guide line 10 formed on the front film 100a and the main guide line 21 of the second tear guide line 20 formed on the back film 100b do not overlap each other (curved portion 112, straight portion 212), the product with the curved portion processed once cannot be opened normally, but the product with the curved portion processed twice can be properly torn and opened while being guided without departing from either the first tear guide line 10 (main guide line 11) or the second tear guide line 20 (main guide line 21). Thus, it was found that the tear-opening performance can be improved by partially (first special area, second special area, third special area, fourth special area) forming the first tear guide line 10 and the second tear guide line with deep and / or thick linear grooves (curved portion processed twice).

[0081] In addition, the packaging bag 100 (packaging bag 4, packaging bag 5) formed of a relatively thin front film 100a and back film 100b has good tear-opening performance without forming the first tear guide line 10 and the second tear guide line 20 partially with deep and / or thick linear grooves. Therefore, forming the first tear guide line 10 and the second tear guide line 20 partially with deep and / or thick linear grooves by processing the curved portion twice is of course effective for packaging bags formed of a relatively thin film (see, for example, packaging bag 5), but it is particularly effective in improving tear-opening performance for packaging bags 100 (see packaging bags 1 to 3) formed of front and back films 100a and 100b that are generally difficult to tear and have a certain thickness. The thickness of the film forming the packaging bag depends greatly on the thickness of the inner layer (PE layer) (see FIG. 11). In the results shown in Fig. 11, when the thickness of the inner layer is 80μm (see packaging bag 5), there is no substantial difference in tear-opening performance between the product with the curved portion processed once and the product with the curved portion processed twice, and both are good, while in the comparatively thick packaging bags (packaging bags 1, 2, and 3) with an inner layer thickness of 110μm or more, the effect (improvement of tear-opening property) of forming the first tear guide wire 10 and the second tear guide wire 20 with partially deep and / or thick linear grooves by processing the curved portion twice is clearly shown. From this, it is presumed that in the packaging bag using the film with a layer structure whose inner layer thickness is between 80μm and 110μm and not less than 100μm, good tear-opening property can be obtained by forming the first tear guide wire 10 and the second tear guide wire 20 with partially deep and / or thick linear grooves.

[0082] When the packaging bag 100 is opened as described above, as shown in Fig. 12, the edge line La of the opening cut of the front film 100a corresponds to the straight portion 111, the curved portion 112, and the straight portion 113 of the main guide line 11(10) (the first auxiliary guide line 12a(10) may also be included). Also, the edge line Lb of the opening cut of the back film 100b corresponds to the straight portions 211, 212, and 213 of the main guide line 21(20) (the first auxiliary guide line 22a(20) may also be included). Here, the curved portion 112 of the main guide wire 11 (10) and the straight portion 212 of the main guide wire 21 (20) corresponding to the second region E2 (see FIG. 10) of the first tear guide wire 10 and the second tear guide wire 20 are formed so as not to be separated and overlapped, so that the portion of the edge line La of the opening cut edge of the front film 100a corresponding to the separated portions (112, 212) and the portion of the edge line Lb of the opening cut edge of the back film 100b do not overlap but are shifted by an amount Δ. Then, the opened packaging bag 100 can be opened by pinching the shifted portions of the back film 100b, and the plastic fastener 19 can be easily opened.

[0083] In the above-mentioned packaging bag 100, even if tearing begins from the right notch 15b provided in the right-side seal portion 17, the packaging bag 100 (front film 100a, back film 100b) can be properly torn and opened while being guided without straying from either the first tear guide line 10 (main guide line 11) or the second tear guide line 20 (main guide line 21), as described above.

[0084] In the above-described embodiment, the front and rear films 100a, 100b have a three-layer structure as shown in FIG. 2, but the present invention is not limited to this. For example, a metal layer such as aluminum having gas barrier properties may be provided between the NY layer 102 and the PE layer 103. In this case, the deep linear grooves may be formed, for example, at a depth deeper than half the depth of the NY layer 102 from the PET layer of the surface layer. Also, the intermediate layer may be composed of multiple layers, or may have other layer configurations.

[0085] The first special region 112a in the main guide wire 11 of the first tear guide wire 10 is a region between the boundary point P1 (first predetermined point) of the curved portion 112 with the straight portion 111 and the second predetermined point P2, i.e., a region in the curved portion 112, but may be a region between the first predetermined point P1 closer to the boundary point with the curved portion 112 than the center point of the straight portion 111 and the second predetermined point P2 of the curved portion 112, i.e., a region continuing from the first predetermined point P1 in the straight portion 111 to the second predetermined point P2 in the curved portion 112. Similarly, the third special region 112b may be a region between the third predetermined point P3 closer to the boundary point with the curved portion 112 than the center point of the straight portion 113 and the fourth predetermined point of the curved portion 112, i.e., a region continuing from the third predetermined point P3 in the straight portion 113 to the fourth predetermined point P4 in the curved portion 112.

[0086] In the above-mentioned embodiment, the first special area 112a, the second special area 212a, the third special area 112b, and the fourth special area 212b are each formed with a deeper linear groove by irradiating the laser light twice, but the number of irradiations is not limited to two. The number of irradiations may be greater than the number of irradiations of the laser light for forming the other parts. In addition, the number of irradiations of the laser light for the other parts is not limited to one, and may be less than the number of irradiations of the laser light for forming the special areas 112a, 212a, 112b, and 212b.

[0087] In the above-mentioned embodiment, the first special area 112a, the second special area 212a, the third special area 112b, and the fourth special area 212b are formed by increasing the number of times of irradiation with the laser light to form linear grooves deeper than other areas, but this is not limited to the above. These special areas can also be formed by linear grooves thicker than other areas, or by linear grooves that are both deep and thick.

[0088] In addition, the method of forming the main induction line 11 of the first tearing induction line 10 and the main induction line 21 of the second tearing induction line 20, which are formed as partially deep linear grooves, is not limited to the method shown in Figure 6A and Figure 7A. For example, the main induction lines 11 and 21 may be formed by one irradiation, and then the parts corresponding to the first special area 112a, the second special area 212a, the third special area 112b, and the fourth special area 212b may be further irradiated with the laser light once.

[0089] Furthermore, by increasing the output of the laser beam or scanning (moving) the laser beam at a slow speed, it is possible to form deep and / or thick linear grooves. Also, by scanning (moving) the laser beam multiple times while shifting it slightly, it is possible to form substantially thick linear grooves.

[0090] The present invention is not limited to the above-described embodiment and its modifications. Various modifications are possible based on the gist of the present invention, and these are not excluded from the scope of the present invention. [Industrial Applicability]

[0091] The packaging bag of the present invention has the effect of being able to be opened by properly tearing along the tear guide lines (easy-open lines) formed on each of the two films (sheets) on the front and back, and is useful as an easy-open packaging bag. [Explanation of symbols]

[0092] 10 First tear guide wire 11 Main guide wire 111 Straight section 112 Curved section 1120 Main curved part 1121 First connecting curved part 1122 Second connecting curved part 112a 1st special area 112b Third Special Area 113 Straight section 12a 1st auxiliary guide wire 12b 2nd auxiliary guide wire 15a left notch 15b Right Notch 16, 17, 18 Seal parts 19 Plastic fasteners 20 Second tear guide wire 21 Main guide wire 212a 2nd Special Area 212b 4th Special Area 211, 212, 213 Straight section 22a 1st auxiliary guide wire 22b 2nd auxiliary guide wire 100 packaging bags 100a Front film 100b Backside film 101 PET layer 102 NY Layer 103 PE layer

Claims

1. A packaging bag comprising a first film and a second film joined at their peripheral portions to form a bag shape, a tear initiation portion being formed at a first joint portion formed by joining the peripheral portions of the first film and the second film, a first tear guide line for guiding tearing from the tear initiation portion being formed in the first film, and a second tear guide line for guiding tearing from the tear initiation portion being formed in the second film, The first tearing guide wire is a first linear portion extending from the tear initiation portion in a direction away from the first joint portion; a curved portion extending from the first straight portion in a curved manner, The second tear guide wire is a straight portion extending from the tear initiation portion, the straight portion overlapping the first straight portion of the first tear guide line and not overlapping the curved portion; In the first tear guide wire, The curved portion includes a first connecting curved portion smoothly continuing from the first straight portion; a main curved portion that smoothly continues from the first connecting curved portion and curves in a direction opposite to the curved direction of the first connecting curved portion; A first special region including a boundary point between the first straight line portion and the first connecting curved portion is formed with a linear groove that is deeper and / or thicker than the linear groove of the first ordinary region from the tear start portion to the first special region; In the second tear guide wire, A packaging bag, in which a second special region corresponding to the first special region of the first tear guide line in the tear direction is formed with a linear groove that is deeper and / or thicker than the linear groove of a second ordinary region corresponding to the first ordinary region of the first tear guide line in the tear direction.

2. In the curved portion, The radius of curvature of the first connecting curved portion is smaller than the radius of curvature of the main curved portion. The packaging bag according to claim 1.

3. 3. The packaging bag according to claim 1, wherein the first special region in the first tear guide line is a region from a first predetermined point, at which the distance to the boundary point with the first connecting curved portion is smaller than the distance to the center point of the first straight portion, to a second predetermined point, at which the distance to the boundary point with the first straight portion is smaller than the distance to the center point of the curved portion.

4. The packaging bag according to claim 3 , wherein the first predetermined point on the first tear guide line is a boundary point between the first straight portion and the first connecting curved portion.

5. The first tear guide wire is a second straight portion extending from the curved portion to a second junction opposite the first junction; The straight portion of the second tear guide line overlaps the second straight portion of the first tear guide line and extends to the second joint portion; In the first tear guide wire, the curved portion has a second connecting curved portion that smoothly continues from the main curved portion to the second straight portion and curves in a direction opposite to the direction of curvature of the main curved portion; A third special region including a boundary point between the second straight line portion and the second connecting curved portion is formed with a linear groove that is deeper and / or thicker than the linear groove of a third ordinary region extending from the second joint side end point of the second straight line portion to the third special region; In the second tear guide wire, The packaging bag according to any one of claims 1 to 4, wherein a fourth special region corresponding to the third special region of the first tear guide line in the tear direction is formed with a linear groove that is deeper and / or thicker than the linear groove of a fourth ordinary region corresponding to the third ordinary region of the first tear guide line in the tear direction.

6. The radius of curvature of the second connecting curved portion is smaller than the radius of curvature of the main curved portion. The packaging bag according to claim 5.

7. The packaging bag according to claim 5 or 6, wherein the third special region in the first tear guide line is a region from a third predetermined point, at which the distance to the boundary point with the second connecting curved portion is smaller than the distance to the center point of the second straight portion, to a fourth predetermined point, at which the distance to the boundary point with the second straight portion is smaller than the distance to the center point of the curved portion.

8. The packaging bag according to claim 7 , wherein the third predetermined point of the first tear guide line is a boundary point between the second straight portion and the second connecting curved portion.

9. In the first tear guide wire, a region between the first special region and the third special region in the curved portion is formed with linear grooves shallower and / or thinner than the linear grooves in the first special region and the third special region, In the second tear guide wire, The packaging bag according to any one of claims 5 to 8, wherein an area corresponding in the tear direction to the area between the first special area and the third special area of ​​the first tear guide line is formed with a linear groove that is shallower and / or thinner than the linear grooves of the second special area and the fourth special area.

10. Each of the first film and the second film is formed of a surface layer, an inner surface layer, and an intermediate layer located between the surface layer and the inner surface layer, The packaging bag according to claim 5 , wherein each of the linear grooves in the first special area, the second special area, the third special area, and the fourth special area is deeper than half the depth of the intermediate layer.

11. The packaging bag according to claim 10, wherein the thickness of the inner surface layer is not less than 100 μm.

12. The first tear guide wire is An auxiliary guide line is provided surrounding the tear initiation portion and intersecting with the first straight portion, In the auxiliary guide line, a predetermined region including an intersection with the first straight line portion is formed with a linear groove that is deeper and / or thicker than linear grooves in other regions, The second tear guide wire is an auxiliary guide line that surrounds the tear start portion, intersects with the straight portion, and overlaps with the auxiliary guide line on the first tear guide line side; The packaging bag according to claim 1 , wherein a predetermined region of the auxiliary guide line including an intersection with the straight portion is formed with a linear groove that is deeper and / or thicker than linear grooves in other regions.

13. A method for forming a tear guide line for the packaging bag according to any one of claims 5 to 11, comprising the steps of: When forming the first tear guide line in the first film, a first step of irradiating a laser beam to form a linear groove from the first ordinary region to the first special region of the first linear portion; a second step of irradiating a laser beam to form a linear groove extending from the first special area to the third special area; A third step of irradiating laser light to form a linear groove from the third special region to the third ordinary region of the second straight portion.

14. A method for forming a tear guide line for the packaging bag according to any one of claims 5 to 11, comprising the steps of: When forming the second tear guide line in the second film, A first step of irradiating a laser beam to form a linear groove from a second ordinary region to a second special region of the straight line portion; a second step of irradiating the straight line portion with a laser beam to form a linear groove from the second special area to the fourth special area; A third step of irradiating laser light to form a linear groove from the fourth special region to the fourth ordinary region of the straight line portion.

Images