JP4822159B2 - Blow molding container - Google Patents

Description

  The present invention relates to the structure of the bottom seal portion of a blow-molded delaminated plastic container.

  A laminated peelable plastic container, which is a blow-molded housing generally called a delamination bottle, is constructed by laminating a flexible bag-like inner layer on an outer layer having a high self-shape retention ability in a state where it can be easily peeled off. Are known.

  This blow-molded delaminated plastic container is obtained by co-extrusion of an outer layer parison and an inner layer parison, which are almost incompatible, into a laminated parison, and blow molding this laminated parison. The bottom seal part, which is crushed and cut by the part, basically has a laminated structure consisting of an outer layer part and an inner layer part that are almost incompatible, so that the bottom crack easily occurs in the outer layer part. was there.

As a conventional technique to eliminate this dissatisfaction, the bottom seal part that is flattened by the pinch-off part of the blow mold and bite-molded is formed into a ridge shape along the parting line by superposing and crimping a pair of rib pieces. There is known a technique disclosed in Patent Document 1 in which a molded bottom rib is used as a main body, and a plurality of biting portions that bite into the other from one of a pair of rib pieces are provided on the bottom rib.
JP 2006-103692 A

  As shown in FIG. 7, the prior art disclosed in Patent Document 1 is a blow-molded delamination plastic container in which a bottom portion is provided at the lower end of a barrel portion provided with a mouth tube portion at the upper end. By forming a ridge shape having a height width, the pressure-bonding area between the outer layer and the inner layer in the bottom seal portion 13 is increased, and the outer layer and the inner layer are provided by providing a plurality of biting portions 16 that are flat in the vertical direction. In addition to further increasing the pressure-bonding area, the resistance against the shearing force parallel to the pressure-bonding surface can be remarkably increased, thereby obtaining the bottom seal portion 13 having high mechanical strength that hardly causes bottom cracks. Making it possible.

  In particular, as shown in FIG. 6, each biting portion 16 includes a bulging portion 18 that bulges at a height within a range in which the pin of the blow mold for molding the biting portion 16 can be forcibly removed. The bottom crack strength is sufficiently increased by the provision of the bulging portion 18.

  Although the above-described conventional technology can surely obtain a high bottom crack resistance, it has recently been required to have a higher bottom crack resistance.

  Therefore, the present invention has been developed to satisfy the above-described demands, and the bottom portion of the blow-molded laminated peelable plastic container has the resistance to peeling of a pair of rib pieces constituting the bottom rib in the bottom seal portion that has been cut-off molded. It is a technical object to further increase the strength, and thus it is intended to strongly prevent the occurrence of bottom cracks in a delaminated plastic container and stably maintain a good use state.

  The blow-molded container of the present invention is a blow-molded delamination plastic container, and a pair of rib pieces are superposed on a bottom seal portion of a bottom portion that is flattened by a pinch-off portion of a blow mold and bitten and molded. The bottom rib is formed by crimping and formed into a ridge shape, and a plurality of elongate horizontal hole biting portions are arranged in a row on the bottom rib.

  The container is formed of a material having a self-shape-holding ability, and an outer layer that forms an outer shell and an inner layer that directly stores contents and forms an inner bag that can be deflated and deformed are laminated in a separable manner. An intake hole is formed in a part of the outer layer for introducing outside air between the outer layer and the inner layer.

  The bottom rib constituting the bottom seal portion of the bottom of the container is formed into a ridge shape by superposing and crimping a pair of rib pieces, and the bottom rib is formed from one of the pair of superposed rib pieces to the other. A plurality of elongate horizontal hole-shaped biting portions are arranged in a row.

  The elongate bite-shaped bite has a bulge that has a bulge and a height that is within a range where the blow mold pin can be forcibly removed. Thus, the hole surface has a corner.

  The bottom seal portion composed of the bottom rib formed into a ridge shape by superposing and pressing a pair of rib pieces has a wall structure in which the outer layer, the inner layer, the inner layer, and the outer layer are stacked in this order along the pressing direction. Since it has a protrusion structure having a height width, it has a large pressure-bonding area, which makes it possible to obtain a high pressure-bonding strength even between an outer layer and an inner layer having low compatibility.

  The biting portion formed in the bottom rib has a structure that bites from one rib piece into the other rib piece, so that the overlapping surface of the outer layer and the inner layer in the bottom rib becomes uneven at this biting portion, thereby The polymerization area increases to increase the pressure bonding strength, and the resistance to the shearing force parallel to the main portion of the pressure bonding surface increases.

  Since the biting part is formed by local pressing deformation of the bottom rib due to a strong pressing force, a strong pressing force acts on the bottom rib part near the biting part, so the outer layer and the inner layer in the biting part are strong. It will be crimped and it will exhibit strong crimping strength.

  In addition, the resin material located around the biting portion is particularly displaced near the bottom portion where the bulging portion is integrally formed, and is displaced more greatly than the other portions. An engagement portion that is curved in an undercut shape with respect to the peeling direction of both rib pieces is formed on the overlapping surface of both rib pieces located around the biting portion.

  Thus, since the meshing portion functions as an undercut meshing in the peeling direction of both rib pieces, the peeling of both rib pieces is strongly prevented.

  In addition, forcible removal at the time of releasing the pin of the blow mold for forming the biting portion is within a range in which the resin material temperature of the bottom seal portion can exhibit viscoelasticity that self-recovers deformation due to the forced removal. Therefore, the meshing portion is surely formed.

  Since the biting portion has a corner portion on the hole surface, providing the corner portion complicates the hole shape of the biting portion, thereby increasing the resistance against the peeling direction.

  Another configuration of the blow-molded container according to the present invention is that adjacent biting portions are arranged at intervals.

  In the case where adjacent biting portions are arranged at intervals, the occurrence of inconvenience that the mechanical strength of the bottom seal portion itself is lowered due to the provision of the plurality of biting portions is prevented.

  Another configuration of the blow-molded container according to the present invention is that at least the biting portion located at the center portion of the bottom seal portion is formed in a “V” shape.

  In the case where the biting portion located at least in the central portion of the bottom seal portion is configured in a “V” shape, each biting portion is ubiquitous in a wide range of up, down, left, and right for its size. As a result, the crimping of both rib pieces can be achieved in a wide range, and the shape is simple, so that molding can be performed easily and easily, and peeling is likely to occur. The peel resistance at the center of the bottom seal portion can be sufficiently increased.

  Another configuration of the blow-molded container according to the present invention is that at least the biting portion located in the center portion of the bottom seal portion is formed in a “T” shape.

  In the case where the biting portion located at the center of the bottom seal portion is formed in a “T” shape, each biting portion is ubiquitous in a wide range of up, down, left and right for its size. As a result, the crimping of both rib pieces is achieved in a wide range, and the “T” shape forms a complicated hole structure, which makes the resistance against the peeling direction extremely high. The peel strength at the center portion of the bottom seal portion, which is strong and easily peeled off, can be sufficiently increased.

  Another configuration of the blow-molded container according to the present invention is that the biting portion is provided in a state of being vertically displaced in a staggered manner by inverting the vertical direction in order.

  By reversing the vertical direction of the biting portion in order, the biting portion is provided in a state of being vertically displaced in a staggered manner, and the crimping force exerted by the biting portion is applied evenly in the vertical direction. In addition, the biting portions can be arranged substantially uniformly over the entire width range of the bottom rib along the parting line without forcibly reducing the interval between the biting portions adjacent in the lateral direction.

  Another structure of the blow molded container according to the present invention is that the biting direction of the biting portion is alternately reversed.

  In the case where the biting direction of the biting part is alternately reversed, the biting direction of the adjacent biting parts is opposite, so that the outer layer and the inner layer in the vicinity are forcibly pulled when the biting part is molded. Since it is greatly extended and deformed, the pressure-bonding area between the outer layer and the inner layer is increased, and the outer layer and the inner layer are pressure-bonded more strongly, thereby increasing the pressure-bonding strength of the entire bottom seal portion.

  Further, since the biting portions are alternately positioned on the opposite side with respect to the main portion of the crimping surface, the plurality of biting portions cause both rib pieces to mesh with each other on both sides of the main portion of the crimping surface. Is structurally enhanced.

Since the present invention has the above-described configuration, the following effects can be obtained.
In the blow-molded container of the present invention, the polymerization surface of the outer layer and the inner layer in the bottom rib becomes uneven due to the biting portion, thereby increasing the polymerization area and increasing the pressure bonding strength, and the main part of the pressure bonding surface The resistance against the shearing force parallel to is increased.

  In addition, an engagement portion that is curved in an undercut shape with respect to the peeling direction of both rib pieces is formed on the overlapping surface of both rib pieces located corresponding to the bulging portion of the biting portion. Since it functions as an undercut meshing with the peeling direction of the pieces, the peeling of both rib pieces is strongly prevented, thereby preventing the occurrence of bottom cracks.

  Furthermore, since each biting part has increased resistance to the peeling direction due to the complicated shape of the hole, the resistance to bottom cracking is increased.

  In the case where the biting portions are arranged at an interval, the formation of the biting portion prevents the occurrence of inconvenience that the mechanical strength of the bottom seal portion itself is lowered. The required strength can be secured and the resistance to bottom cracking can be exhibited stably.

  In the case where the biting portion is configured in a “V” shape, each biting portion can be ubiquitous in a wide range of up, down, left, and right for its size. Can be achieved over a wide range, so that both rib pieces can be crimped approximately evenly to obtain a stable crimped state, and the shape is simple, so molding is easy and easy. As a result, good moldability can be obtained.

  In the case where the biting portion is configured in a “T” shape, each biting portion can be ubiquitous in a wide range of up, down, left, and right for its size. Can be achieved over a wide range, so that both rib pieces can be crimped approximately evenly to obtain a stable crimped state, and a hole structure with a complicated shape is formed. The resistance against the resistance becomes extremely strong, and thereby a high resistance to bottom cracking can be obtained.

  If the biting portion is provided in a state where it is displaced in a staggered manner by reversing the vertical direction in order, the vertical direction of the bottom rib and the entire width range of the bottom rib along the parting line Since the biting part can be arranged almost evenly without difficulty, it is possible to achieve evenly enhanced peel resistance and crimping strength over the entire bottom rib, thereby maintaining stable crimp assembly of the bottom rib. can do.

  If the biting direction of the biting part is alternately reversed, the biting direction of adjacent biting parts is reversed, so that both rib pieces bite into each other and mesh with each other, and in the biting part The pressure-bonding force between the outer layer and the inner layer is increased, and the pressure-bonding area between the outer layer and the inner layer in the bottom seal portion is increased, thereby further increasing the peel resistance and the pressure-bonding strength between the outer layer and the inner layer in the bottom seal portion. .

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front view of a container 1 according to the present invention, FIG. 2 is a side view, FIG. 3 is a bottom view, and the container 1 is made of a synthetic resin material such as polyethylene and polypropylene, and has a necessary self-shape retaining ability. An outer layer 2 molded in a bag, and a synthetic resin material having low compatibility with the outer layer 2 such as nylon, ethylene vinyl alcohol copolymer, polyethylene terephthalate, etc. Is a blow-molded container in which are laminated (see FIG. 2).

  The body 4 of the container 1 has a cylindrical shape, and stands upright at the upper end of the body 4, and external air is applied to the outer layer 2 portions before and after the mouth tube portion 5 in which a thread is engraved on the outer peripheral surface. An intake hole 6 is formed between the outer layer 2 and the inner layer 3, and a bottom portion 7 having a circular bottom wall 10 is connected to the lower end of the body portion 4.

  The bottom portion 7 (see FIG. 3) includes a peripheral leg wall 8 constituting a leg portion of the container 1, a bottom wall 10 surrounded by the leg wall 8 and recessed in the container 1, and the bottom wall 10 The bottom seal portion 13 is integrally connected and is located on the parting line and crosses the bottom wall 10.

  The leg wall 8 (see FIGS. 2 and 3) has a wall structure in which a substantially cylindrical wall portion on the outer side and a lower end of a tapered cylindrical portion whose diameter is expanded on the inner side are connected in an arc shape. In the portion where the parting line is located, a recessed portion 9 is formed by cutting out a part thereof.

  The bottom wall 10 (see FIGS. 2 and 3) has a spherical arc-shaped slope portion 11 continuous to the inner peripheral edge of the leg wall 8 and a central portion of the slope portion 11 that traverses along the parting line and has a major axis of parting. The dome structure has a substantially elliptical spherical arc wall shape along the line, and is composed of a thick raised portion 12 that is bent inward of the container 1.

  The bottom seal portion 13 (see FIGS. 3, 4, 5, and 6) traverses the center of the raised portion 12 of the bottom wall 10 with both ends being continuous with the recessed portion 9 of the leg wall 8. When the parison is blow-molded into the container 1, the pair of rib pieces 14 obtained by crushing the parison flatly from the front and the back and biting it out is formed into a ridge shape by polymerizing and pressing as it is. The bottom rib 15 is mainly formed, and a biting piece 20 that is a bite of the parison is formed on the bottom end surface of the bottom rib 15 over the substantially entire length of the bottom rib 15.

  The bottom rib 15 has a plurality of elongated horizontal hole-shaped biting portions 16 having corners on the hole surface that bite into the other rib piece 14 from one rib piece 14, which is larger than the thickness of the rib piece 14. By forming the depth slightly smaller than the thickness of 15 and alternately reversing the depression direction and reversing the vertical posture alternately, the rows are formed in a zigzag-like displacement state.

  In addition, the bottom seal portion 13 has a vertical rib structure that crosses the bottom wall 10 along the parting line, and the occurrence of sagging deformation at the center portion of the bottom wall 10 due to shrinkage deformation with time after completion of blow molding. It is surely prevented.

  Each biting portion 16 is basically in the shape of a horizontal hole that is long to the left and right, and is arranged in a zigzag-like displacement state by alternately inverting the vertical posture as shown in FIGS. As shown in FIG. 6, the longitudinal cross-sectional structure forms a bulging portion 18 with a bulging height within a height range in which a blow mold pin can be forcibly removed, integrally with the bottom portion. It has become.

  Thus, since the biting part 16 has a structure having the bulging part 18, as shown in FIG. 6, the biting part 16 provided with the bulging part 18 is pushed and molded. In the vicinity of the biting portion 16, an engagement portion 19 in which the overlapping surfaces of both rib pieces 14 are curved in an undercut structure is formed, and this engagement portion 19 strongly prevents separation of both rib pieces 14. To do.

  FIG. 4 shows a first embodiment of the biting portion 16, which is provided with a corner portion 16a in the center portion and is formed into a laterally long and narrow hole shape that is bent into a “V” shape having a large opening angle. The bulging portion 18 is located on the bent side, and the ones at both ends of the three central portions invert the vertical posture.

  In the first embodiment shown in FIG. 4, the biting portions 16 at the left and right ends have a “V” shape with a small degree of bending due to dimensional relationships.

  In the first embodiment of the biting portion 16 shown in FIG. 4, the two portions defined by the corner portions 16a are equally opposed in the vertical direction and the left-right direction, so that the biting portion 16 exhibits. The drag force against the peeling direction is applied substantially uniformly to the entire area of the bottom seal portion 13.

  FIG. 5 shows a second embodiment of the biting portion 16, in which a corner portion 16a is formed at the center of the lateral hole portion elongated in the left and right directions, and a short lateral hole portion is provided in a row in the vertical direction. The bulging portion 18 is positioned on the hole surface of the lateral hole portion that is elongated to the left and right on the side opposite to the side on which the corner portion 16a is provided. The vertical posture is reversed.

  In the second embodiment shown in FIG. 5, the biting portions 16 at both the left and right ends are simply formed in a horizontal hole shape elongated in the left and right directions due to dimensional relationships.

  In the second embodiment of the biting portion 16 shown in FIG. 5, the structure as a horizontal hole of the biting portion 16 is complicated, and accordingly, the resistance against the peeling direction exerted by the biting portion 16 is strong. Can be.

  The crimping portion 17 formed on the rib piece 14 portion on the biting direction side of each biting portion 16 has a sufficiently thin flat plate shape, but the shape of the biting portion 16 is basically a horizontal hole shape that is long to the left and right. In addition, since the bulging portion 18 is provided, the size (area) of the bulging portion 18 can be made large without difficulty.

  Further, the thickness of the crimping portion 17 is desirably as thin as possible within a range in which the required mechanical strength can be maintained, and about 1/10 to 20 times the thickness of the bottom rib 15 is appropriate. is there.

  Thus, by making the crimping portion 17 into a sufficiently thin flat plate shape, the bottom seal portion 13 hardly contracts at the time of cooling and hardening, and even if a contracting deformation force acts from the surroundings, this deformation force is reduced. It absorbs as bending deformation of the whole crimping | compression-bonding part 17, and, thereby, the peeling generation | occurrence | production in the crimping | compression-bonding part 17 is prevented.

  The outer layer 2 is made of low density polyethylene, and the inner layer 3 is made of nylon. The total height is 154.3 mm, the outer diameter of the body portion is 44.8 mm, the height of the bottom rib 15 is 5 mm, the width is 38 mm, and the thickness is 1.8 mm. 7 is used, the prior art example in which the bottom seal portion 13 shown in FIG. 7 is provided, the first embodiment of the present invention in which the example shown in FIG. 4 is provided, and FIG. The bottom crack resistance was compared with the second embodiment of the present invention provided with the examples shown in FIG.

In the prior art example and the two embodiments of the present invention, the number of biting portions 16 is 5 and the bulging height of the bulging portion 18 is the same as 0.1 mm. for technical example 20.32 mm ^2, in the case of the first embodiment of the present invention in the case of the second embodiment of 22.32mm ^2, and the present invention was 23.39mm ^2.

  A pressure force is applied to the bottom portion 7 of the container 1 of the prior art example and the two embodiment examples of the present invention at a rate of 20 mm / min from the direction along the parting line using an autograph measuring instrument. When the test was conducted several times, in the case of the prior art example, the bottom crack occurred when the pressing force of 55.31N on which the strain amount of 3.48 mm was generated on the average was applied. In the case of the first embodiment, a bottom crack occurs when a pressing force of 193.67N on which an amount of distortion of 7.75 mm is generated on the average, and in the case of the second embodiment of the present invention. Then, on the average, a bottom crack occurred when a pressing force of 179.37 N, which produced a strain amount of 7.62 mm, was applied.

  As is apparent from the results of the comparative measurement, the bottom crack strength of the two embodiments of the present invention shown in FIG.

1 is an overall front view showing an embodiment of the present invention. FIG. 2 is an overall side view, partly broken, of the embodiment shown in FIG. 1. It is a whole bottom view of the example of embodiment shown in FIG. FIG. 2 is a bottom enlarged vertical front view of the embodiment shown in FIG. 1 that is vertically cut at a position slightly deviated from a parting line. It is a bottom part expansion longitudinal front view which carried out the longitudinal section in the position which remove | deviated from the parting line slightly, which shows the other Example of a bottom part. FIG. 6 is an enlarged vertical cross-sectional side view of an essential part showing details of a structure of a bottom seal part in the embodiment example shown in FIGS. 4 and 5. It is a principal part expansion longitudinal cross-section side view which shows the detail of the structure of the bottom seal part of the container of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Container 2; Outer layer 3; Inner layer 4; Body part 5; Mouth part 6; Inlet hole 7; Bottom part 8; Leg wall 9; Recessed part 10; Bottom wall 11; Slope part 12; Part 14; rib piece 15; bottom rib 16; biting part 16a; corner part 17; crimping part 18; bulging part 19; meshing part 20;

Claims (6)

  A blow-molded delaminated plastic container that has an air inlet hole in the outer layer, and a pair of rib pieces superposed on the bottom seal part that is flattened by the pinch-off part of the blow mold and cut into pieces. A plurality of biting portions are arranged in a row, and are formed in a bottom rib formed into a ridge shape by pressure bonding, and bite into one side from the other of the pair of overlapped rib pieces. On the surface portion, a bulging portion bulging with a height within a range in which the pin of the blow mold for forming the biting portion can be forcibly removed is provided integrally with the bottom portion of the biting portion, and the biting A blow-molded container in which the portion is formed as an elongated horizontal hole having a corner on the hole surface.   The blow-molded container according to claim 1, wherein the adjacent biting portions are arranged at an interval. The blow-molded container according to claim 1 or 2, wherein at least the biting portion located at the center of the bottom seal portion is formed in a "V" shape. The blow-molded container according to claim 1 or 2, wherein at least the biting portion located at the center of the bottom seal portion is formed in a "T" shape.   The blow-molded container according to any one of claims 1 to 4, wherein the biting portion is provided in a state of being vertically displaced in a staggered manner by reversing the vertical direction in order.   The blow molded container according to any one of claims 1 to 5, wherein the biting direction of the biting portion is alternately reversed.

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