JP2013189247A - Packaging bag with gusset, apparatus and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the top opening of a packaging bag with a gusset formed by inflation molding to be easily opened by a finger, and to prevent a heat sealing failure etc. caused by a difference in the number of stacked films.SOLUTION: Resin packaging bags (1, 1') having an opening at the top are a gusset packaging bag having a gusset (4) formed by fold lines (6, 7, 8) extending in a direction parallel to the center axis of the bag. Front and rear films (11, 12) of the bag are deviated by a predetermined distance (L) in the width direction of the bag, and gripping margins (17, 18) of widths corresponding to the deviation distance are formed on the right and left edges of the bag. In inflation molding, a tube (T) of a resin sheet or a film (F) fed upward from an annular die (26) is formed locally thick by applying cooling air (A1) to predetermined angle regions (α, β).

Description

  The present invention relates to a packaging bag with a gusset, a manufacturing apparatus and a manufacturing method thereof, and more specifically, with a top opening type gusset made of a thin resin sheet or a resin film molded product formed by an inflation molding method. The present invention relates to a packaging bag, a manufacturing apparatus and a manufacturing method thereof.

  Resin-made packaging bags used for packaging food in large-scale commercial facilities and food retail stores are widely used. This type of bag is used for various purposes such as waste packaging for disposing of household garbage, simple packaging for easily storing or carrying food, sundries and the like.

  In general, in an inflation molding apparatus for manufacturing such a resin packaging bag, a molten resin obtained by heating and melting polyethylene resin raw material resin pellets is supplied to an annular die, and is formed into a tubular shape (tube shape) from a slit-type nozzle of the annular die. Extruded upward. The resin expands by the air flow blown out from the central region of the annular die, and the outer peripheral surface of the resin tube is cooled by the external cooling air flow that flows upward from the annular die, thereby extending the circular shape to a desired expansion ratio. It is fed upward as a tubular resin film having a cross section. The tubular resin film is flattened by contact with a stabilizer disposed above the annular die, and is sandwiched between pinch rolls. As a result, the take-up roll is formed in the form of a continuous belt-like multilayer sheet stacked in two layers. Wound around. This type of inflation molding apparatus is described in, for example, Japanese Patent Application Laid-Open No. 11-1105048.

  As described above, in an inflation molding apparatus that continuously molds a resin film tube, an inflation molding apparatus including a gusset molding apparatus that continuously shapes the outline of a gusset (gusset) in a resin film tube is known.

  FIG. 19 is a horizontal cross-sectional view conceptually showing the relationship between the gusset forming apparatus and the resin film tube. In general, the gusset forming apparatus has an isosceles triangular outline with the top portion facing upward, but in order to simplify the drawing and description, the gusset forming apparatus is a single plate or flat plate member as shown in FIG. explain.

  The tube T of the resin film is flattened by making contact with the plate-like stabilizer A disposed on both sides of the tube T, and the gusset contour is formed by the pair of gusset forming devices B. The gusset forming device B is disposed on a vertical (vertical) plane D including the central axis C of the tube T and parallel to the contact surface of the stabilizer A, and is positioned symmetrically with respect to the central axis C. As shown in FIG. 19 as the depression E, the tube T comes into contact with the gusset forming member B and is depressed in a V shape. The depression E is shaped in the form of a bag gusset as the tube T is flattened by the stabilizer A. Since the contact portions J of the gusset forming member B are arranged symmetrically on both sides of the tube T on the vertical plane D, the gusset derived from the V-shaped depression E is formed uniformly on the left and right sides of the bag. An inflation molding apparatus provided with such a gusset molding apparatus B is described in, for example, Japanese Patent Application Laid-Open No. 8-286875.

  The tube T that has been flattened and shaped with a gusset is continuously wound around the core tube of the winding device via a pinch roll. The resin film wound in the form of a winding roll is transferred to a bag forming apparatus, fed out from the winding roll in the bag forming apparatus, and fed to a welding apparatus. The resin film is subjected to belt-like seam welding or heat sealing at the bottom of the bag by a welding device, and then cut into a predetermined bag length by a cutting device.

  FIG. 20 is a front view showing a resin packaging bag in which left and right gussets are formed.

  The resin packaging bag N includes left and right gusset portions G. The gusset portion G is formed by a side edge fold line H on the front side and the back side of the bag and a fold line I in the valley bottom portion. The fold lines H on the front side and the back side are positioned at exactly the same position in the front view or the back view and overlap exactly. Such a packaging bag with a gusset can reduce the width of a packaging box or the like for storing a stack of packaging bags because the width of the bag is small by the amount of the resin film folded at the gusset portion G, and the opening of the bag. Can be opened to a relatively large square or rectangular shape, which is advantageous compared to a bag without a gusset.

Japanese Patent Laid-Open No. 11-115048 JP-A-8-286875

  However, in such a plastic packaging bag in which the front and back sides are perfectly aligned, the front and back side films are in close contact with each other, and the opening edge of the bag looks like a single sheet or film. This makes it difficult to open the bag opening. This is a well-known event that many housewives, etc. have experienced on a daily basis at large-scale commercial facilities, such as the structure or form of the bag so that the opening of the bag can be easily opened with fingers. It is desirable to improve.

  The inflation molding apparatus is designed and controlled so that the thickness of the resin film tube is uniform over the entire circumference. However, in a gusseted packaging bag, four resin films overlap four layers at the gusset portions on both sides in the width direction, whereas only two resin films overlap two layers at the center in the width direction. Absent. On the other hand, the welding device uniformly welds or heat-seals the bottom of the bag over the entire width, so that the resin film is welded at a heating temperature and pressure suitable for either the side or the center. Then, there exists a tendency for the welding defect to generate | occur | produce in the other of a side part or a center part. For example, when the heating temperature and pressure of the welding apparatus are set so that the four resin films are fitted to the side portions overlaid on the four layers, only the two resin films are excessive in the center portion overlaid on the two layers. There is a tendency to be heated and pressurized, and conversely, if the heating temperature and pressure of the welding device are set so that only the two resin films fit into the center of the two layers, four resin films However, there is a tendency that sufficient heating and pressurization are not performed at the side portion where the four layers overlap. Such a defect causes the heat seal part to be broken, peeled off, etc., and measures to avoid this are desired.

  This invention is made in view of such a subject, The place made into the objective relates to the packaging bag with a top opening type gusset which consists of a molded product of a thin resin sheet or a resin film, The opening of a bag is made. To provide a packaging bag with a gusset, which can be easily opened with fingers, and which can prevent poor welding at the bottom of the bag due to a difference in the number of overlapping films or the number of film layers, and a manufacturing apparatus and a manufacturing method thereof. It is in.

In order to achieve the above object, the present invention is a top-opening resin packaging bag made of a thin resin sheet or resin film molded by an inflation molding method, in a direction parallel to the central axis of the bag In a gusseted packaging bag in which a gusset is formed by a fold line extending to
Left and right fold lines (6) located at the side edges of the front film (11) of the bag (1) so as to form the gusset (4), and the back side of the bag so as to form the gusset (4) The left and right fold lines (7) located on the side edge of the film (12) are biased by a predetermined distance (L) in the width direction of the bag, and have a width dimension corresponding to the distance and Provided is a packaging bag with a gusset, wherein gripping margins (17, 18) on the front side and back side (front side and back side) that can be picked with fingers are formed on the left and right edges of the bag.

  According to the above configuration of the present invention, when the left and right gripping margins are picked with fingers and pulled outward of the bag, the bag is deformed asymmetrically in the front-rear direction. Spacing, the top opening of the bag opens to a generally parallelogram outline. Therefore, an unreasonable action or operation to open the top opening of the bag by separating the tightly attached top opening edge film portions with fingers is not particularly required.

  According to a preferred embodiment of the present invention, a sheet or film portion (Z1, Z3) located in a zone where two resin sheets or films are laminated in two layers is composed of four resin sheets or films in four layers. Is thicker than the sheet or film portion (Z2) located in the band overlapped with each other.

  According to another preferred embodiment of the present invention, the sheet or film part (Z1, Y1) constituting the margin (17, 18) and the left and right fold lines constituting the valley bottom part (10) of the gusset (4) ( The sheet or film portion (Z3, Y3) in the central zone located between 8) is the sheet or film portion (13, 13) located in the zone (Z2) between the margin and the central zone and constituting the valley bottom portion. It is thicker than 14,15,16).

  According to still another preferred embodiment of the present invention, the sheet or film part (Z1, Y1) constituting the margin (17, 18) and the left and right folding lines constituting the valley bottom part (10) of the gusset (4) The sheet or film portion (Z3, Y3) in the central zone located between (8) is thicker than the sheet or film portion (Z2) located in the zone between the margin and the central zone.

  Suitably, the distance (L) is set to a dimension of at least 5 mm or more, preferably 10 mm or more, and is 1/4 or less, preferably 1/8 or less, more preferably, the width of the bag. The dimension is set to 1/10 or less. More preferably, the left and right gussets (4) have a point-symmetrical outline in plan view with respect to the central axis of the bag parallel to the gusset, and the distance is set to the same size on the left and right.

  In a preferred embodiment of the present invention, the linear fusion part (5) of the packaging bag that forms the seal bottom part (3) by heat sealing includes the left and right fold lines (8) constituting the valley bottom part (10) of the gusset part. A deformed portion (9) extending transversely is provided at the center in the width direction of the bag. The deformed portion is composed of left and right curved portions (9a) that are gently curved from the linear portion of the linear fusion portion, and a downwardly bulged portion (9b) that is formed between the left and right curved portions and is gently curved. The The arc-shaped portion of the downward bulge crosses the left and right fold lines (8) constituting the valley bottom portion of the gusset portion. The fold line (8) constitutes a boundary where the number of sheets or layers of the overlapping sheets or films changes, but according to the above configuration in which the arc-shaped portion of the lower bulging portion crosses the fold line of the valley bottom portion, such a boundary It is possible to prevent excessive stress (excessive stress that may be generated when opening and closing the bag) from acting on the heat seal portion that intersects with, and to prevent occurrence of poor fusion in this portion.

The present invention also provides a manufacturing apparatus for manufacturing a packaging bag with a gusset having the above structure by an inflation method.
A gusset molding device (30) for forming the gusset by contacting the outer surface of the tube (T) of the resin film (F), and a stabilizer having a contact surface for contacting the tube and flattening the tube (41), and the contact portion (35) of the gusset forming apparatus that contacts the tube includes a central axis (C) of the tube and is a vertical plane parallel to the contact surface (45) of the stabilizer Provided is a manufacturing apparatus characterized in that it is disposed at a position deviated by a predetermined distance (X1, X2) on the opposite side to (D).

  According to the manufacturing apparatus having the above configuration, the packaging bag having the above configuration can be easily and continuously manufactured by an inflation method.

  Preferably, the manufacturing apparatus is a local cooling device that applies a cooling airflow to predetermined angular regions (α, β) of the tube in order to change the thickness of the resin sheet or film (F) in the circumferential direction of the tube (F) ( 50). More preferably, the local cooling device (50) includes a cooler (53a) that cools indoor air or outside air, and a blower (53b) that pumps the cooling air. Preferably, the contact portion (35) is disposed at a point-symmetrical position in plan view with respect to the vertical (vertical) central axis (C) of the tube.

The present invention further relates to a method for producing a packaging bag with a gusset, in which a top opening type gusseted packaging bag (1,1 ') made of a molded product of a thin resin sheet or film is formed by an inflation molding method,
The tube (T) of the resin sheet or film (F) is sent upward from the annular die (26), and is attached to the tube by a gusset molding device (30) provided with a contact portion (35) that contacts the outer surface of the tube. In the manufacturing method of a packaging bag with a gusset that shapes a gusset contour and flattens the tube by a stabilizer (41) having a contact surface (45) that contacts the tube.
Cooling air (A3) is blown to a predetermined angle region (α, β) around the tube (T) of the resin sheet or film (F) fed upward from the annular die, and the angle region The sheet or film part (Y1, Y3) is locally thickened to form a thick part of the sheet or film,
The contact portion (35) is disposed at a position that is deviated by a predetermined distance (X1, X2) on the opposite side to a vertical plane that includes the central axis (C) of the tube and is parallel to the contact surface of the stabilizer. Provided is a method for producing a packaging bag with a gusset, characterized in that front and back gripping margins (17, 18) that can be picked with fingers are formed on the left and right edges of the bag by the thick portions. .

  According to the manufacturing method of the said structure, the packaging bag of the said structure can be manufactured simply and continuously by the inflation method.

  Preferably, the cooling air (A3) is 10 ° C. and 30 ° C. higher than the temperature (t2) of the external cooling air (A1) supplied to the entire circumference of the tube (T) by the external cooling air flow discharge means (26) of the annular die. It is cooled to a temperature lower by a temperature difference (t2−t3) of less than ℃. If desired, the external cold air (A1) is heated, and the temperature difference (t2−t3) is controlled to 10 ° C. or more and 30 ° C. or less. Preferably, the height position (h1) of the minimum diameter portion (R1) of the tube (T) and the height position (preferably 1/3) of the maximum diameter (R2) of the tube (1/3). Cooling air (A3) is applied to the tube within the height range between h2).

  According to the above configuration of the present invention, the top opening type gusseted packaging bag made of a thin resin sheet or resin film molded product, the opening of the bag can be easily opened with fingers, and the number of overlapping films Or the packaging bag with a gusset which can prevent the poor welding of the bag bottom part resulting from the difference in the number of film layers, its manufacturing apparatus, and a manufacturing method can be provided.

FIG. 1 is a front view showing a configuration of a packaging bag with a gusset according to the present invention. FIG. 2 is a cross-sectional view of the packaging bag shown in FIG. FIG. 3 is a side view of the packaging bag shown in FIGS. 1 and 2. FIG. 4 is a schematic plan view showing a state in which the top opening of the packaging bag shown in FIGS. FIGS. 5 (A) to 5 (E) are plan views showing stepwise and conceptually the deformed state of the bag when the top opening of the packaging bag shown in FIGS. 1 to 4 is opened. FIG. 6 is a front view showing another configuration of the packaging bag with gussets according to the present invention. 7 is a cross-sectional view of the packaging bag shown in FIG. FIG. 8 is a partially enlarged front view showing the configuration of the bottom of the packaging bag shown in FIGS. 6 and 7. 9 is a cross-sectional view taken along the line II of FIG. FIG. 10 is a plan view showing a state where the top opening of the packaging bag shown in FIGS. 6 to 9 is opened. FIG. 11 is a system configuration diagram schematically showing the overall configuration of an inflation molding apparatus for manufacturing a packaging bag according to the present invention. FIG. 12 is a horizontal cross-sectional view conceptually showing the relationship between the gusset forming apparatus constituting the inflation molding apparatus and the resin film tube. FIG. 13 is a cross-sectional view conceptually showing the difference in film thickness in each band of the packaging bag. FIG. 14 is a horizontal cross-sectional view conceptually showing the difference in film thickness of each part in the tube immediately before coming into contact with the stabilizer. FIG. 15 is a system configuration diagram schematically showing the configuration of the local cooling device that constitutes the inflation molding device. FIG. 16 is a plan view schematically showing the configuration of the local cooling device shown in FIG. FIG. 17 is a plan view showing a modification of the local cooling device. FIG. 18 is a plan view showing a further modification of the local cooling device. FIG. 19 is a horizontal cross-sectional view conceptually showing the relationship between a gusset molding device and a resin film tube in a conventional inflation molding device. FIG. 20 is a front view showing a conventional resin packaging bag in which left and right gussets are uniformly formed.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1, 2, and 3 are a front view, a cross-sectional view, and a side view showing a configuration of a packaging bag with a gusset according to the present invention. FIG. 4 is a schematic plan view showing a state where the top opening of the bag shown in FIGS.

  A top opening type gusseted packaging bag 1 (hereinafter referred to as “bag 1”) is a bag made of a resin film such as a translucent polyethylene film, and is a flattened structure of a tubular film formed by an inflation method. Have The bag 1 has a top opening 2, a seal bottom 3, and a gusset (gusset) 4. A bag bottom fusion zone or a linear fusion part 5 (hereinafter referred to as “linear fusion part 5”) extending over the entire width of the bag 1 is formed on the seal bottom 3. For example, the front view dimension of the bag 1 is about 330 mm × 200 mm. The back view of the bag 1 appears the same as the front view of FIG.

  The bag 1 has fold lines (fold lines) 6, 7, 8 extending in the up-down direction (direction parallel to the center axis of the bag), and the resin film constituting the bag 1 is the left and right fold lines 6 on the front side, the back side The left and right folding lines 7 and the folding line 8 of the valley bottom portion 10 (FIGS. 4 and 5) of the gusset portion 4 are bent so as to overlap each other. The front film portion 11 between the left and right fold lines 6 and the back film portion 12 between the left and right fold lines 7 have the same width dimension and are disposed at positions shifted in the width direction as a whole by a distance L. The front film portion 11 and the back film portion 12 are biased toward one side. The left and right front side fold film portions 13 and 14 located between the fold line 6 and the fold line 8 at least partially overlap the left and right back side fold film portions 15 and 16 located between the fold line 7 and the fold line 8. .

  The width L1 of the front side folding film portion 13 between the folding lines 6 and 8 located on the left side in FIGS. 1 and 2 is the back side folding film portion between the folding lines 7 and 8 located on the left side in FIGS. It is larger than 15 width L2. The width L3 of the front side folding film portion 14 between the folding lines 6 and 8 located on the right side in FIGS. 1 and 2 is the back side folding film portion between the folding lines 7 and 8 located on the right side in FIGS. It is smaller than 16 width L4. The band Z1 (the margin band on the left side) of the front side folded film part 13 protruding laterally and outward (leftward in FIG. 1) by a distance (width) L from the back side folded film part 15 should be picked with fingers. A backside gripping margin 17 (shown by hatched hatching in FIG. 1) is formed. Similarly, the band Z1 (margin band on the right side) of the back-side folded film portion 16 that protrudes laterally and outward (rightward in FIG. 1) from the front-side folded film portion 14 is a front surface that can be picked with fingers. A side holding margin 18 (shown by hatched lines in FIG. 1) is formed. Preferably, the width L1 is at least 10 mm greater than the width L2, and the width L4 is at least 10 mm greater than the width L3. In this example, the widths L of the grip margins 17 and 18 are both about 15 mm and are set to the same dimension. However, the width L of the left and right grip margins 17 and 18 need not necessarily be set to the same size.

  Considering each part of the bag 1 based on the number of overlapping resin films, the bag 1 has two resin films overlapping in a margin band Z1 having a width L, and four resin films in a gusset band Z2 having widths L2 and L3. Has a structure in which two resin films overlap two layers in a central zone Z3 having a width L5.

  The film thicknesses T1 and T3 of the margin zone Z1 and the central zone Z3 are set to be the same as those of the gusset zone Z2 in order to prevent the heat seal peeling, tearing, etc. from occurring due to poor adhesion, seal breakage, etc. The thickness is set to be larger than the film thickness T2. That is, the resin film constituting the bag 1 does not have a uniform thickness as a whole, but changes in thickness in the circumferential direction, and the film thicknesses T1 and T3 of the margin band Z1 and the central band Z3 are: It is thicker than the film thickness T2 of the gusset zone Z2. In the present embodiment, the thicknesses T1 and T3 are set to dimensions of 13 μm or more (20 μm or less), and the thickness T2 is set to a dimension of 12 μm or less (6 μm or more).

  5 (A) to 5 (E) are plan views conceptually showing a deformed state of the bag 1 when the top opening 2 of the bag 1 is opened.

  When the left and right grip margins 17 and 18 are picked with fingers and the bag 1 is pulled outward in the in-plane direction of the bag 1 as indicated by an arrow P, the bag 1 is shown in FIGS. 5 (A) to 5 (C). As shown in FIG. As a result, the front film portion 11 and the back film portion 12 are separated from each other, and the top opening 2 of the bag 1 gradually opens to a substantially parallelogram outline as shown in FIGS. 5 (D) and 5 (E). . Therefore, an unreasonable action of opening the top opening of the bag 1 by separating the film portions 11 and 12 of the top opening edge closely attached with fingers is not particularly required. FIG. 4 shows a state in which the top opening of the bag 1 is thus opened.

  6 and 7 are a front view and a cross-sectional view showing another configuration of the packaging bag with a gusset according to the present invention, and FIGS. 8 and 9 are configurations of the bottom portion of the packaging bag shown in FIGS. 6 and 7. It is the partial expanded front view and partial expanded sectional view which show. FIG. 10 is a plan view showing a state in which the top opening of the packaging bag shown in FIGS. 6 to 9 is opened. In addition, in each figure of FIGS. 6-10, the same referential mark is attached | subjected to the component which is the same as that of each component shown in FIGS. 1-6, or equivalent.

  In the bag 1 shown in FIGS. 1 to 5, the width L5 of the central zone Z3 is relatively larger than the widths L2 and L3 of the zone Z2. For this reason, as shown in FIG. 4, the top opening of the bag can only open to a rectangular (parallelogram) profile elongated in the width direction, and therefore, the opening degree of the top opening of the bag is limited or limited. In the case of such a packaging bag, it is assumed that a situation where it is difficult to store bulky food, food, etc. in the bag can occur. On the other hand, in the bag 1 'shown in FIGS. 6 to 10, the width L5 of the central zone Z3 is relatively considerably smaller than the widths L2 and L3 of the zone Z2. For this reason, the top opening of the bag 1 'expands relatively large in the depth direction as shown in FIG. 10, and opens in a form in which the square is slightly distorted. In such a packaging bag with a large opening at the top, bulky food, foodstuffs, etc. can be stored in the bag relatively easily. In addition, such a structure of the packaging bag enables the adoption of a bag shape elongated in the vertical direction, that is, a bag shape having a storage space having a large height and a large depth with respect to the width. The front view size of the bag 1 shown in FIGS. 6 to 10 is, for example, about 350 mm × 130 mm.

  In the bag 1 shown in FIGS. 1 to 5, the linear fusion part 5 extends straight in the width direction, but the linear fusion part 5 of the bag 1 ′ shown in FIGS. The part has a deformed part 9. As shown in FIGS. 8 and 9, the deformed portion 9 is formed between the left and right arcuate curved portions 9a gently curved from the straight portion of the linear fusion portion 5 with a predetermined curvature radius r ′ and the left and right curved portions 9a. And an arcuate downward bulging portion 9b that is gently curved with a predetermined radius of curvature r. The downward bulging portion 9b crosses the left and right folding lines 8 that define the central zone Z3. Therefore, the intersection K between the broken line 8 and the linear fusion part 6 is located on the downward bulging part 9b.

  The curvature radius r of the downward bulging portion 9b centering on the curvature center CP is set to a dimension larger than the width of the central zone Z3. For example, when the width of the central zone Z3 is 8 mm, the curvature radius r is 15 mm. Set to The center of curvature CP is positioned on the center line of the bag 1 ′ and is positioned at a position above the level of the linear fusion part 5. For example, the upward displacement d of the center of curvature CP shown in FIG. 8 is 5 mm. Is set. Further, the radius of curvature r 'of the curved portion 9a centering on the center of curvature CP' is smaller than the radius of curvature r of the downward bulging portion 9b, and is set to, for example, about 2 to 5 mm.

  Similar to the bag 1 shown in FIGS. 1 to 5, in the bag 1 ′, two resin films overlap in two layers in the margin zone Z1 having the width L, and four resin films in the gusset zone Z2 having the widths L2 and L3. Has a structure in which two resin films overlap two layers in a central zone Z3 having a width L5. 1 to 5, the film thicknesses T1 and T3 of the margin zone Z1 and the central zone Z3 are set to values larger than the film thickness T2 of the gusset zone Z2. The occurrence of peeling, tearing, etc. of the heat seal such as cutting can be prevented.

  Other configurations of the bag 1 ′ shown in FIGS. 6 to 10 are substantially the same as or equivalent to those of the bag 1 shown in FIGS. 1 to 5, and the behavior when the top of the bag 1 ′ is opened is Since the behavior is substantially the same as or equivalent to 1, the further detailed description of the bag 1 ′ is omitted to avoid redundant description.

  FIG. 11 is a system configuration diagram schematically showing the configuration of an inflation molding apparatus for manufacturing the bags 1 and 1 ′.

  The inflation molding device 20 includes an extruder 21 having a drive unit 22 and a resin extrusion cylinder device 23, and an annular die 26 connected to the extruder 21 via an adapter 25. The extruder 21 includes a raw material charging hopper 24 arranged at the upper part of the casing of the resin extrusion cylinder device 23 and a rotary extrusion screw device 27 arranged in the casing. The extrusion screw device 27 has a heating zone 28 provided with heating means, and the heating zone 28 heats and melts the resin raw material pellets W put into the hopper 24. The drive unit 22 incorporates a drive device that rotationally drives the shaft portion of the extrusion screw device 27, and the spline or blade portion of the extrusion screw device 27 rotates as the shaft portion rotates. Molten resin is sent to the resin flow path or resin extrusion channel 29.

  The resin flow path 29 passes through the adapter 25 disposed at the tip of the extrusion screw device 27 and communicates with the resin discharge port (lip portion or slit portion) of the annular die 26. The air flow path 31 passes through the axial core portion of the annular die 26, and the air flow outlet is disposed in the central region in plan view of the annular die 26. The air flow path 31 communicates with an air source (not shown), and an air flow (AIR) supplied from the air source is upward from a central region in plan view of the annular die 26 via the air flow discharge port. Discharge.

  The annular die 26 has an air ring or an external cooling ring (hereinafter referred to as “air ring”) that constitutes an external cooling air flow discharge means. The air ring is annularly arranged outside the resin discharge port. The external cold air flow discharging means blows an external cold air flow for cooling the outer surface of the tubular resin film F to the outer peripheral region of the tubular resin film F. The external cooling air flow lowers the surface temperature of the tubular resin film F to cause the tubular resin film F to expand at an appropriate height position, and maintains the rising upright form of the tubular resin film F. It acts on the outer peripheral surface of the film F. Thus, the tube T made of the tubular resin film F is continuously supplied vertically (vertically) upward from the annular die 26.

  A pair of plate-like stabilizers 41 that regulate the ascending path of the tube T are disposed immediately above the annular die 26, and the pair of pinch rolls 40 are arranged in an upper region of the stabilizer 41. A gusset molding apparatus 30 is disposed between the left and right stabilizers 41. The stabilizer 41 regulates the moving path of the tube T to flatten the tube T and guide the tube T to the nip portion of the pinch roll 40.

  The inflation molding apparatus 20 includes a local cooling device 50 that changes the film thickness of the tube T in the circumferential direction while having a configuration in which the stabilizer 41 is biased in such a conventional device configuration.

  FIG. 12 is a horizontal cross-sectional view conceptually showing the relationship between the gusset forming device 30 and the tube T.

  The tube T of the tubular resin film F is flattened by contacting the contact surfaces 45 of the stabilizer 41 disposed on both sides of the tube T, and the gusset portion 4 is shaped by the pair of gusset molding devices 30. The gusset forming device 30 is disposed at a position shifted (offset) to the opposite side or the opposite side with respect to the vertical (vertical) plane D including the vertical (vertical) central axis C of the tube T. That is, the contact portion 35 of the gusset forming device 30 is positioned at a position that is biased in the direction of the stabilizer 41 on the opposite side or the opposite side with respect to the vertical plane D including the central axis C of the tube T by the distances X1 and X2. .

  The stabilizer 41 and the gusset molding device 30 are supported by a common machine frame or a support frame (not shown). The machine frame or the support frame includes a support mechanism (not shown) that positions the gusset forming device 30 at the biased position and fixes the gusset molding device 30 at the biased position. In addition, the gusset forming apparatus 30 actually has an isosceles triangular outline with the top portion facing upward, but in order to simplify the drawing and description, the gusset forming device 30 is a single plate or flat plate member as shown in FIG. The molding apparatus 30 will be described.

  Due to the bias of the contact portion 35, the tube T comes into contact with the contact portion 35 of the gusset forming device 30 at a position shifted to the opposite side by the distances X1 and X2 with respect to the vertical plane D and is depressed in a V shape (depression E). As the tube T is flattened by the stabilizer 41, the gusset portion 4 shown in FIGS. 1, 2, 6, and 7, that is, the gusset portion having an uneven front and rear valley centered around the fold line 8. In this way, a band which becomes the holding margins 17 and 18 on the front side and the back side is continuously formed in the tube T. In this example, the distances X1 and X2 are set to the same dimension. However, the distances X1 and X2 do not necessarily have to be set to the same dimension.

  As shown in FIG. 11, the upper guide roll 42 is disposed on the side of the pinch roll 40, and the tube T completely crushed by the pinch roll 40 travels to the side as a flat belt-like sheet F ′. The upper guide roll 42 turns downward, and then the lower guide roll 43 turns sideways, is fed to the winding device 60, and is wound around the core tube 61 of the winding device 60. The belt-like sheet F ′ wound in the form of a winding roll is transferred to a bag forming device (not shown) and fed to a welding device (not shown). The belt-like sheet F ′ is fed from the winding roll in the bag forming apparatus, and after the linear fusion part 5 is heat-sealed in the welding apparatus, it is cut into a predetermined bag length by the cutting apparatus. 'Manufactured.

  FIG. 13 is a cross-sectional view conceptually showing the difference in film thickness in each zone Z1, Z2, and Z3 of the bag 1 ′ (FIGS. 6 to 10), and FIG. 14 shows a state immediately before contacting the stabilizer 41. 3 is a horizontal cross-sectional view conceptually showing a difference in film thickness at each part in a tube T. FIG. FIGS. 15 and 16 are a system configuration diagram and a plan view schematically showing the configuration of the local cooling device 50. The following description relates to the bag 1 ′, but the same applies to the bag 1 (FIGS. 1 to 5).

  FIG. 13 shows a margin zone Z1 and a central zone Z3 (film thicknesses T1 and T3) of the bag 1 ′ and gusset zones Z2a and Z2b (film thicknesses T2a and T2b) constituting the gusset zone Z2 (film thickness T2). It is shown. Since the gusset zone Z2a includes the film portions 13 and 15 or the film portions 14 and 16, the overall length of the gusset zone Z2a is significantly larger than the overall length of the gusset zone Z2b. FIG. 14 shows the portions Y1, Y3, Y2a, Y2b of the tube T corresponding to the zones Z1, Z3 (thicknesses T1, T3) and the gusset zones Z2a, Z2b (film thicknesses T2a, T2b). The portions Y1 and Y3 of the tube T corresponding to the zones Z1 and Z3 (thicknesses T1 and T3) extend in an angle range of angles α and β around the central axis X of the tube T. The local cooling device 50 cools the tube portions Y1 and Y3 and thickens the tube portions Y1 and Y3.

  15 shows the configuration of the annular die 26 and the local cooling device 50, and FIG. 16 shows the positional relationship (planar position) between the cooling air discharge port 51 of the local cooling device 50 and the tube T. ing.

  The annular die 26 connected to the resin flow path 29 has an annular resin discharge port 26a for extruding the molten resin M supplied by the resin flow path 29 upward, and an annular air ring 26b constituting the external cooling air flow discharge means. With. The air ring 26b includes an annular outer cold air discharge port 26c arranged concentrically around the resin discharge port 26a, and an annular outer cold air chamber 26d connected to the discharge port of the blower 70 via the air supply pipe 71. Consists of The blower 70 sucks air OA at room temperature or atmospheric temperature from the surrounding space, and pumps the air OA to the outside cold air chamber 26d through the air supply pipe 71. The air supply pipe 71 is provided with a heater 72 such as an electric heater or a hot water heater for heating the air flow. The heater 72 is operated at a time when the air temperature in the surrounding space is lowered (winter season or the like). The air in the external cooling air chamber 26d is discharged upward as an external cooling air flow A1 from the air discharge port 26c, and the outer peripheral surface of the tube T is uniformly cooled in the circumferential direction. The tube T expands to a predetermined diameter by an increase in the tube internal pressure due to the air flow A2 supplied from the air flow path 31 into the tube T and an outer peripheral surface cooling action due to the external cooling air flow A1.

  The local cooling device 50 includes four cooling air chambers 52 arranged at positions corresponding to the portions Y1 and Y3 of the tube T, and an air cooling device connected to each cooling air chamber 52 via a cooling air supply pipe 54. 53. Each cooling air chamber 52 includes a cooling air discharge port 51 that blows cooling air A3 against the portions Y1 and Y3 of the tube T. The cooling air discharge port 51 is inclined slightly upward with respect to the horizontal plane, and the cooling air discharge port 51 flows out the cooling air A3 obliquely upward. The cooling air discharge port 51 blows cooling air to a tube portion where the tube T starts to expand or a tube portion slightly expanded in diameter. Preferably, the cooling air discharge port 51 is between a height position h1 at which the tube T starts to expand from the minimum diameter R1 and a height position h2 at which the diameter of the tube T expands to the maximum diameter R2 × 1/2. It arrange | positions so that cooling air may contact | win the tube T in the height range.

  The air cooling device 53 includes an air-cooled or water-cooled cooler 53 a (shown by a broken line) and a blower 53 b (shown by a broken line) that pumps cooling air to the cooling air chamber 52. The air cooling device 53 cools the ambient air OA (room air or the like) sucked from the surrounding space under the suction pressure of the blower 53b by the cooler 53a, and cools the cooled air to the cooling air chamber under the supply pressure of the blower 53b. Pump to 52.

  In general, in the work period (for example, 9:00 am to 6:00 pm) in the summer and intermediate periods (spring or autumn), the room temperature is approximately 20 to 35 ° C. Therefore, the blower 70 has a temperature t1 = Ambient air OA of about 20 to 35 ° C. is sucked and supplied to the external cold air chamber 26d, and the external cold air discharge port 26c supplies the external cold air A1 of temperature t2 = 20 to 35 ° C. to the external cold air discharge port 26c. From above. The external cooling air A1 flows upward along the outer surface of the tube T, and cools the outer peripheral surface of the tube T uniformly. On the other hand, the air cooling device 53 sucks ambient air at a temperature t1 = about 20 to 35 ° C. and cools it to about 10 to 15 ° C., and cools the cooling air A3 at a temperature t3 = 10 to 15 ° C. from the cooling air discharge port 51. Spray on the outer surface of the tube T. The temperature difference (t2−t3) between the temperatures t2 and t3 is approximately 10 to 20 ° C., and due to such a temperature difference, the thickness of the resin film F changes in the circumferential direction.

  In general, in winter work hours (for example, from 9 am to 6 pm), the room temperature is approximately 10 to 20 ° C., so it is difficult to ensure the temperature difference between the temperatures t2 and t3. For this reason, the heater 72 is operated and the externally cooled air flow A1 is heated. For example, the temperature t2 of the external cooling air A1 is set to about 20 ° C., and the temperature t3 of the cooling air A3 is set to about 10 ° C. Therefore, the temperature difference (t2−t3) of about 10 ° C. is the air A1, Secured during A2.

  As shown in FIG. 16, the four cooling air chambers 52 are arranged at the same level at intervals in the circumferential direction. The cooling air discharge ports 51 provided in the respective cooling air chambers 52 are arranged at predetermined angular intervals so as to blow the cooling air A3 only on the tube portions Y1 and Y3 within the angle range of the angles α and β. . The tube portions Y1 and Y3 that are supercooled as compared with the other portions of the tube T are thickened, and thus the margin zone Z1 and the central zone Z3 of the bag 1 'described above are formed. As a modification, two cooling air chambers 52 are arranged on both sides of the tube T as shown in FIG. 17, and two cooling air discharge ports 51 are arranged in each cooling air chamber 52. The air cooling device 50 may be configured such that the cooling air A3 is sprayed only on the tube portions Y1 and Y3 within the angle range of β.

  The inventor uses such an inflation molding apparatus 20 to prototype the bags 1 and 1 ′ under the conditions of temperatures t1, t2 = about 20 ° C., and temperatures t3 = about 10 ° C. As a result, the thickness T1, It has been found that a bag 1 ′ having T3 = 16 μm or more and thickness T2 = 12 μm or less can be manufactured by an inflation molding method.

  FIG. 18 is a plan view showing a further modification of the local cooling device 50.

  The cooling air discharge port 51 of the local cooling device 50 shown in FIG. 18 is not only the tube portions Y1 and Y3 within the angle range of the angles α and β, but also the tube portion within the angle range of the angle γ including the angles α and β. It is comprised so that cooling air A3 may be sprayed on Y1, Y2b, and Y3. Further, the cooling air discharge port 51 shown in FIGS. 16 and 17 extends straight in parallel with the diameter, but the cooling air discharge port 51 shown in FIG. 18 curves in a generally complementary manner with respect to the outer peripheral surface of the tube T. .

  According to the experiment of the present inventor, when cooling air is blown over the entire tube portions Y1, Y2b, Y3 within the angle range of the angle γ, the tube portion Y2b is relatively thicker than the tube portions Y1, Y3. Therefore, the tube portion Y2b is only slightly thickened. This is considered due to the fact that the resin hardly moves from the tube portion Y2a to the tube portion Y2b. For this reason, also with the local cooling device 50 shown in FIG. 18, only the tube portions Y1 and Y3 can be substantially thickened.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications or changes can be made within the scope of the present invention described in the claims. Is possible.

  For example, the width L of the holding margins 17 and 18 can be appropriately changed according to the desired size and contour of the bag 1.

  In addition, the height position of the cooling air discharge port 51 and the temperature, pressure, air volume, wind speed, etc. of the cooling air A3 are appropriately set and changed according to the material of the resin film and the surrounding environmental conditions (temperature, humidity, etc.). It is of the nature to get.

  Furthermore, as the cooling air discharge port 51, various types of blowout ports such as a nozzle shape, a slit shape or a louver shape can be adopted.

  In the above embodiment, the cooling air supply pipe 54 is connected to the cooling air chamber 52. However, it is also possible to spray the cooling air A3 directly onto the tube T from the end of the cooling air supply pipe 54. .

  INDUSTRIAL APPLICABILITY The present invention is applied to a top-opening-type gusseted packaging bag made of a thin resin sheet or resin film molded by an inflation molding method, a manufacturing apparatus and a manufacturing method thereof. According to the present invention, the packaging bag with a gusset is configured so that the top opening can be easily opened with fingers, and further, the welding failure of the bag bottom due to the difference in the number of overlapping films or the number of film layers is prevented. Its practical value is remarkable.

DESCRIPTION OF SYMBOLS 1, 1 'Packaging bag 2 Top part opening part 3 Seal bottom part 4 Gusset (gusset) part 5 Linear melt | fusion part 6-8 Polyline 10 Valley bottom part 11 Front film part 12 Back surface film part 13-16 Film part (Gazette part)
17, 18 Grasping margin 20 Inflation forming device 26 Annular die 30 Gazette forming device 35 Contact portion 40 Pinch roll 41 Stabilizer 45 Contact surface 50 Local cooling device 51 Cooling air discharge port 52 Cooling air chamber 53 Air cooling device 60 Winding device A3 Cooling air C Tube vertical (vertical) central axis D Vertical (vertical) plane F Tubular resin film T Tube L, L1-L4 Width X1, X2 Distance α, β, γ Angular region

Claims (14)

A top-opening type resin packaging bag made of a thin resin sheet or resin film molded by an inflation molding method, with a gusset formed by a fold line extending in a direction parallel to the central axis of the bag In the packaging bag,
The left and right fold lines (6) located at the side edges of the front sheet or film (11) of the bag (1,1 ') so as to form the gusset (4), and the gusset (4) are formed. The left and right fold lines (7) located on the side edge of the back sheet or film (12) of the bag are offset by a predetermined distance (L) in the width direction of the bag, corresponding to the distance A packaging bag with gussets, characterized in that front and back gripping margins (17, 18) having a width dimension that can be picked with fingers are formed at the left and right edges of the bag.   The sheet or film part (Z1, Z3) located in the zone where two resin sheets or films are stacked in two layers is the sheet or film located in the zone where four resin sheets or films are stacked in four layers The packaging bag with a gusset according to claim 1, wherein the packaging bag is thicker than the portion (Z2).   Sheet of the central band located between the sheet or film part (Z1, Y1) constituting the margin (17, 18) and the left and right fold lines (8) constituting the valley bottom part (10) of the gusset (4) Or the film portion (Z3, Y3) is located in a zone (Z2) between the margin and the central zone and is more than the sheet or film portion (13, 14, 15, 16) constituting the valley bottom portion. The packaging bag with a gusset according to claim 1, wherein the packaging bag is thickened.   Sheet of the central band located between the sheet or film part (Z1, Y1) constituting the margin (17, 18) and the left and right fold lines (8) constituting the valley bottom part (10) of the gusset (4) Alternatively, the film portion (Z3, Y3) is thicker than a sheet or film portion (Z2) located in a zone between the margin and the central zone. Packaging bag with gusset.   The distance (L) is set to a dimension of at least 5 mm or more and is set to a dimension of 1/4 or less of the width dimension of the bag. Packaging bag with gusset. The linear fusion part (5) of the packaging bag forming the seal bottom part (3) by heat sealing is a deformed part extending across the left and right folding lines (8) constituting the valley bottom part (10) of the gusset part ( 9) at the center in the width direction of the bag,
The deformed portion includes a left and right curved portion (9a) gently curved from a linear portion of the linear fusion portion, and a gently bulged downward bulging portion (9b) formed between the left and right curved portions. Configured,
The packaging bag with a gusset according to any one of claims 1 to 5, wherein the arc-shaped portion of the downward bulging portion crosses the left and right folding lines (8) constituting the valley bottom portion. In the manufacturing apparatus of the packaging bag with a gusset which manufactures the packaging bag with a gusset (1,1 ') of any one of Claims 1 thru | or 6 by an inflation method,
A gusset forming device (30) for forming the gusset by contacting the outer surface of the tube (T) of the resin sheet or film (F), and a contact surface (45) for flattening the tube by contacting the tube A contact portion (35) of the gusset forming apparatus that contacts the tube, and includes a central axis (C) of the tube and a contact surface (45) of the stabilizer. A device for manufacturing a packaging bag with a gusset, which is disposed at a position deviated by a predetermined distance (X1, X2) on the opposite side with respect to a vertical plane (D) parallel to the vertical plane (D).   In order to change the thickness of the resin sheet or film (F) in the circumferential direction of the tube (F), a local cooling device (50) for applying a cooling airflow to a predetermined angle region (α, β) of the tube is provided. The manufacturing apparatus according to claim 7.   The manufacturing apparatus according to claim 8, wherein the local cooling device (50) includes a cooler (53a) that cools indoor air or outside air, and a blower (53b) that pumps cooling air.   The said contact part (35) is a manufacturing apparatus of Claim 3 arrange | positioned in the point-symmetrical position in planar view with respect to the vertical center axis (C) of the said tube. A method for producing a packaging bag with a gusset, in which a top opening-type gusseted packaging bag (1,1 ') made of a thin resin sheet or film molding is formed by an inflation molding method,
The tube (T) of the resin sheet or film (F) is sent upward from the annular die (26), and is attached to the tube by a gusset molding device (30) provided with a contact portion (35) that contacts the outer surface of the tube. In the manufacturing method of a packaging bag with a gusset that shapes a gusset contour and flattens the tube by a stabilizer (41) having a contact surface (45) that contacts the tube.
Cooling air (A3) is blown to a predetermined angle region (α, β) around the tube (T) of the resin sheet or film (F) fed upward from the annular die, and the angular region The sheet or film part (Y1, Y3) is locally thickened to form a thick part of the sheet or film,
The contact portion (35) is disposed at a position that is deviated by a predetermined distance (X1, X2) on the opposite side to a vertical plane that includes the central axis (C) of the tube and is parallel to the contact surface of the stabilizer. A method for producing a packaging bag with gussets, wherein gripping margins (17, 18) on the front side and the back side that can be picked with fingers are formed on the left and right edges of the bag by the thick portions.   The cooling air (A3) is 30 ° C. and 30 ° C. higher than the temperature (t2) of the external cooling air (A1) supplied to the entire circumference of the tube (T) by the external cooling air flow discharge means (26) of the annular die. The manufacturing method according to claim 11, wherein the method is cooled to a temperature lower by a temperature difference (t2−t3) of less than or equal to degrees Celsius.   The manufacturing method according to claim 12, wherein the outside cold air (A1) is heated, and the temperature difference (t2-t3) is controlled to 10 ° C or more and 30 ° C or less. Within the height range between the height position (h1) of the minimum diameter portion (R1) of the tube (T) and the height position (h2) corresponding to 1/2 of the maximum diameter (R2) of the tube The manufacturing method according to any one of claims 11 to 13, wherein the cooling air (A3) is applied to the tube.

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