JP2004059077A - Blow-molded vessel and method for blow-molding the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a delamination bottle type blow-molded vessel of excellent shock durability having a structure of sufficiently enhancing the strength of a bottom seal part in a delamination bottle, and a blow-molding method therefor. <P>SOLUTION: This delamination bottle comprises an outer layer to form a regular-formed outer shell and an inner layer which is peelably laminated on the outer layer to form a volume-reducing and deformable inner bag. A seal part is formed of a first seal part which is squeezed flat by a pinch-off part of a blow split die and a second seal part which is located immediately above the first seal part and heat-bonded in a direction across the first seal part in an intersecting manner so that resins in a vicinity of the seal parts are heat-bonded to form a thick-walled part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention allows the inner layer forming the deformable inner bag to be peelably laminated and formed in the outer layer forming the fixed outer shell, thereby enabling the use of the content liquid to be poured out without changing the external shape. The present invention relates to a blow-molded container made of a synthetic resin and a molding method thereof.
[0002]
[Prior art]
A blow-molded container, generally referred to as a delami bottle, is known in which an inner layer forming a deformable inner bag is releasably laminated within an outer layer forming a fixed outer shell. Is obtained by extruding an outer layer and an inner layer having almost no compatibility into a multi-layer parison by co-extrusion, and blow-molding the multi-layer parison.The bottom seal portion is crushed and formed by a pinch-off portion of a blow split mold. Has a dissatisfaction that a bottom crack is easily generated since it basically has a laminated structure of an outer layer portion and an inner layer portion having almost no compatibility.
[0003]
Conventional techniques for increasing the strength of the bottom seal portion include, for example, JP-A-59-115234, JP-A-3-32013, and JP-A-7-88943. Various shapes of ribs (protrusions) are formed at the bottom of the crushed bottom seal to increase the area of heat welding and to make the V-shape of the inner surface of the seal gentle. And a method of pushing up the inner layer resin upward.
[0004]
11 and 12 show a container 1 in which an example of a conventional bottom seal portion is formed. Rib pieces 14 are continuously provided below the bottom seal portion 9 ′. By forming the bottom seal portion 9 ′ into a ridge shape having a height width in this way, the outer seal 2 and the outer layer 2 in the bottom seal portion 9 ′ are formed. By increasing the pressure-bonding area with the inner layer 3 and providing the biting portion 15, not only the pressure-bonding area between the outer layer 2 and the inner layer 3 is further increased, but also the resistance to shearing force parallel to the pressure-bonding surface is increased. This makes it possible to obtain a bottom seal portion that is unlikely to cause bottom cracks and has high mechanical strength.
[0005]
[Problems to be solved by the invention]
However, even in the prior art as described above, particularly, the outer layer and the inner layer are formed so as to be thin so that the volume reduction deformation can be easily performed at the bottom seal portion of a container such as a delami bottle which is releasably laminated. Although there is heat welding between the inner layers, there is no heat welding between the outer layers, which is located in a sandwich shape so as to sandwich this inner layer from both sides, it is formed relatively thick and should resist external force, There is a problem that a bottom crack may occur if the content liquid is dropped or a large impact is applied in a filled state.
[0006]
Therefore, the present invention has been devised to solve the above-mentioned problems in the prior art, and has a new structure for sufficiently increasing the strength of the bottom seal portion of the delamination bottle as a technical subject, and has excellent impact resistance. An object of the present invention is to provide a delami bottle type blow molded container and a molding method thereof.
[0007]
[Means for Solving the Problems]
Among the means of the present invention for solving the above technical problem, the means according to the first aspect of the present invention is an outer layer forming a fixed outer shell, and an inner bag which is detachably laminated with the outer layer and which can be reduced in volume and deformable. An inner layer that forms
A first seal portion formed by being squashed flat by a pinch-off portion of a blow split mold, and a second seal portion located immediately above the first seal portion and formed by heat welding in a direction intersecting with the first seal portion. With the seal portion, the resin near the two seal portions is heat-welded to form a thick portion, and the seal portion is formed in a cross shape at the bottom portion,
It is in.
[0008]
In the conventional blow molding, a bottom seal portion (first seal portion) formed by being flattened and crushed by a pinch-off portion of a blow split mold is linearly formed on a bottom wall of the bottom portion in a direction of a parting line line. Since it is formed and has a relatively large thickness, it exerts an effect like a kind of rib piece on a force acting on the bottom and particularly in a plane parallel to the sealing surface, but acts on a right angle direction on the contrary. With respect to the force, that is, the pulling force and the bending force for peeling off the sealing surface, the effect as the rib piece is small, and the outer layer and the inner layer are separated, and the bottom of the container is cracked.
[0009]
Here, the configuration according to claim 1 is such that the second seal portion is formed immediately above the first seal portion in a direction intersecting the first seal portion, and is perpendicular to the first seal portion. For forces acting in the direction, this second seal portion acts as a rib piece, ie, opposing external forces acting in various directions on the bottom of the container by two intersecting seals. It becomes possible.
[0010]
Furthermore, since the resin near the two seal portions is thermally welded to each other to form a thick portion, deformation near the seal portion due to external force can be suppressed, and delamination between the outer layer and the inner layer can be suppressed, and the bottom seal can be suppressed. It is possible to reliably prevent the part from cracking.
[0011]
According to a second aspect of the present invention, in the first aspect of the present invention, the crossing angle between the first seal portion and the second seal portion is set to approximately 90 ° to form a cross-shaped seal portion.
[0012]
According to the above configuration, since the cross-shaped rib is formed on the bottom, it is possible to more reliably counter external forces in all directions.
[0013]
According to a third aspect of the present invention, in the first or the second aspect of the present invention, there is provided an adhesive band for bonding and fixing the outer layer and the inner layer over the entire height range.
[0014]
According to the above configuration of the third aspect, the adhesive band formed over the entire height range can restrict the volume reduction deformation of the inner layer, prevent the flow passage of the content from being blocked, and until the content substantially disappears. Thus, it is possible to supply a delami bottle type container having good pourability.
[0015]
When a pair of adhesive strips are formed in the vicinity of the left and right parting lines of the trunk in consideration of the appearance of the front of the trunk of the container, the adhesive strip traverses the second seal portion at the bottom, so that the second seal is formed. A portion where the outer layer and the inner layer are bonded is formed at a substantially central portion of the portion, so that the bottom seal portion can be further strengthened.
[0016]
In the molding method according to the fourth aspect of the present invention, in molding a multi-layer parison formed of at least a cylindrical outer layer and a cylindrical inner layer, the parison is formed at a predetermined angle with respect to a parting line direction below a die. Forming a second seal portion by sealing in a strip shape in the direction to be formed;
When the second seal portion reaches a position immediately above the bottom pinch-off portion of the split mold, a portion immediately below the second seal portion is pinched off by the split mold and blow-molded.
[0017]
According to the molding method of the fourth aspect, the parison is sandwiched from both sides by a pair of seal bars of the sealer device at a position below the die, so that the parison itself is in a molten state, so that it is easily sealed in a narrow band shape. Two seal portions can be formed, and the angle with the parting line can be set according to the direction of the seal bar.
[0018]
When the extrusion of the parison progresses and the second seal part descends and reaches just above the pinch-off part of the split mold, the mold is clamped and the pinch-off part is crushed flat to form the first seal part. By doing so, the first seal portion can be formed directly below the second seal portion.
[0019]
After the mold clamping is completed, blow molding is performed by blowing blow air into the parison. At this time, since the molten resin near the second seal portion expands and deforms, the first seal portion located immediately below and fixed by the pinch-off portion is used. And heat-welded in the vicinity of the molten resin, and a thick portion is formed near the seal portion.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show an embodiment of a blow-molded container according to the present invention. The container 1 is made of a synthetic resin material such as polyethylene or polypropylene and has an outer shell having a required self-shape holding capability. An outer layer 2 molded as a body, and a synthetic resin material such as nylon, ethylene vinyl alcohol copolymer, polyethylene terephthalate, etc., having low compatibility with the outer layer 2 and formed into a bag shape which can be reduced in volume. This is a blow molded container in which the inner layer 3 is laminated.
[0021]
The body 6 of the container 1 has a cylindrical shape, and a mouthpiece 7 having a thread is formed upright at the upper end of the body 6, and a depressed bottom wall is provided at the lower end of the body 6. Are provided continuously. (See FIG. 1) The shape of the body 6 is not limited to a cylindrical shape, but can be selected according to the purpose, for example, an elliptical cylindrical shape.
[0022]
Further, a pair of intake holes 9 for allowing outside air to enter between the outer layer 2 and the inner layer 3 are formed in the outer layer 2 at a position 90 ° from the parting line 5 in the mouthpiece portion 7, and a spout and a check are provided. A cap having a valve or the like is screwed together and used as a delamination bottle. Further, a cap can be used in combination with a dispenser pump.
[0023]
The bottom 8 forms the leg of the container 1 around the bottom wall, and in the center of the bottom wall, the pinch-off portion 27 of the split mold 26 located on the parting line 5 and substantially crossing the bottom wall. The first seal portion 9 is formed in a crushed and bite-like shape, and the first seal portion 9 has a configuration in which a rib piece 14 is provided below.
[0024]
Further, a second seal portion 10 formed by heat welding is formed so as to intersect the first seal portion 9 at an angle of about 90 °, and a resin near the first seal portion 9 and the second seal portion 10 is formed. Are heat-welded to form the thick portion 11.
[0025]
FIG. 3 is a longitudinal sectional front view showing the state of lamination near the first seal portion, and FIG. 4 is a longitudinal sectional side view, in which a laminate composed of two layers of an outer layer 2 and an inner layer 3 is substantially triple folded and laminated. The thick part 11 is formed. (FIGS. 3 and 4 each show a stacked state in which the portions slightly distant from the center of the bottom are vertically cut parallel to the first seal portion 10 and the second seal portion.)
[0026]
Next, FIGS. 5 to 7 show one embodiment of the above-described method for molding the blow-molded container of the present invention. The blow molding of the container 1 is performed by forming the cylindrical outer layer 2 and the outer layer 2. The multilayer parison 21 is formed by co-extrusion with the cylindrical inner layer 3 located on the inner side from the die 22 for multilayer forming.
[0027]
The second seal portion 10 is formed by hot-pressing the parison 21 with a pair of seal bars 24 using a sealing machine 23 at a position immediately below the die 22 so as to sandwich the parison 21 in a narrow band shape. At this time, the direction of the seal is substantially 90 ° with respect to the parting line 25 of the split mold 26. (The arrow in FIG. 6 indicates the operation direction of the seal bar 24.)
[0028]
Next, when the second seal portion 10 reaches a position immediately above the pinch-off portion 27 of the split mold 26, the pinch-off portion 27 pinches off the portion immediately below the second seal portion 10 to form the first seal portion 9. Then, blow air 29 is blown from above the parison 21 through the core guide 28 to form the container 1. (See Figs. 5 and 7)
[0029]
During this blowing, the molten resin in the vicinity of the second seal portion 10 expands and deforms to form the bottom 8 of the container 1, so that the molten resin in the vicinity of the second seal portion 10 is pressed against the molten resin in the vicinity of the first seal portion 9. Then, they are thermally welded to each other to form a thick portion 11 in the bottom portion 8 of the container 1 in a laminated state as shown in FIGS.
[0030]
The bottom 8 of the container 1 obtained in this manner has a sealing portion formed in a cross shape and a thick portion 11 formed at the peripheral portion thereof, so that the bottom portion 8 has sufficient strength to prevent cracking even under severe conditions. Can be secured.
[0031]
In the above-described embodiment, the intersection angle between the first seal portion 9 and the second seal portion 10 is approximately 90 °, but the intersection angle is not limited to approximately 90 °, and the required seal portion strength is required. Can be determined in consideration of conditions such as restrictions on the arrangement positions of the blow molding machine and the sealing machine 23.
[0032]
FIG. 8 shows another embodiment of the blow-molded container of the present invention, in which the outer layer 2 and the inner layer 3 are adhesively fixed at positions on the left and right parting lines 5 over the entire height range. A vertical band-shaped adhesive band 4 is formed, and the other configuration is the same as that of the above-described embodiment of the present invention. The number and formation position of the adhesives 4 are not limited to the present embodiment, but can be selected according to the purpose and necessity.
[0033]
9 and 10 show another embodiment of the molding method according to the present invention, which shows an example of a method for molding a parison 21 for molding the container 1 on which the adhesive band 4 is formed. A pair of narrow adhesive layers 13 is formed between the outer layer 2 and the inner layer 3 at the parting line 25 direction (vertical direction in FIG. 10).
[0034]
Since the adhesive layer 13 is located substantially at the center of the second seal portion 10 in which the parison 21 is sealed by the seal bar 24 (see FIG. 10B), the second portion is formed at the bottom 8 of the container 1 after blow molding. At a substantially central portion of the seal portion 10, the outer layer 2 and the inner layer 3 are bonded and fixed by the adhesive layer 13, so that the bottom seal portion can be more reliably prevented from cracking. (See Fig. 11)
[0035]
【The invention's effect】
The present invention has the above-described configuration, and has the following effects.
According to the first aspect of the present invention, the two intersecting seals can oppose external forces acting on the bottom of the container in various directions, and the resin near both seal portions is thermally welded. Since the thick portion is formed, deformation near the seal portion can be suppressed, and cracks in the bottom seal portion can be reliably prevented.
[0036]
According to the second aspect of the present invention, since cross-shaped ribs are formed at the bottom, it is possible to more reliably counter external forces in all directions.
[0037]
According to the third aspect of the present invention, the adhesive band formed over the entire height range restricts the volume reduction deformation of the inner layer, so that the flow passage of the contents is prevented from being blocked and the contents are almost eliminated. It is possible to supply a delami bottle type container having good pourability, and since a portion where the outer layer and the inner layer are adhered and fixed substantially at the center of the second seal portion, cracking of the bottom seal portion can be more reliably performed. To prevent.
[0038]
According to the fourth aspect of the present invention, the two seal portions can be formed to intersect at the bottom and the thick portion can be formed at the periphery of the seal portion without impairing the productivity of the container.
[Brief description of the drawings]
FIG. 1 is an overall perspective view showing one embodiment of a blow molded container of the present invention.
FIG. 2 is a bottom view showing one embodiment of the blow-molded container of the present invention.
FIG. 3 is a longitudinal sectional front view taken along the line AA in FIG. 2;
FIG. 4 is a vertical sectional side view as viewed in the direction of arrows BB in FIG. 2;
FIG. 5 is an explanatory view showing one embodiment of the molding method of the present invention in a front view.
FIG. 6 is an explanatory view showing, in a plan view, a parison sealing method using a sealing machine in one embodiment of the molding method of the present invention.
FIG. 7 is an explanatory view showing a pinch-off state of a parison in a front view in one embodiment of the molding method of the present invention.
FIG. 8 is an overall perspective view showing another embodiment of the blow molded container of the present invention, partially cut away, and FIG. 9 is a longitudinal sectional view showing a parison in another embodiment of the molding method of the present invention.
FIG. 10 is a plan sectional view taken along lines CC and DD in FIG. 9;
FIG. 11 is a longitudinal sectional front view showing an example of a conventional blow-molded container.
FIG. 12 is a bottom view showing an example of a conventional blow-molded container.
[Explanation of symbols]
1; Container 2: Outer layer 3; Inner layer 4; Adhesive band 5; Parting line 6; Body 7; Cylinder 8; Bottom 9; First Seal 9 '; Bottom Seal 10; Thick portion 13; adhesive layer 14; rib piece 15; bite portion 16; intake hole 21; parison 22; die 23; Guide 29; blow air

Claims (4)

In a delamination bottle formed of an outer layer (2) forming a fixed outer shell, and an inner layer (3) laminated releasably with the outer layer (2) to form an inner bag capable of volume reduction and deformation, A first seal portion (9) formed by being flattened and crushed by a pinch-off portion (27) of a mold (26); and a first seal portion (9) located immediately above the first seal portion (9). The second seal portion (10) formed by heat welding in a direction intersecting with (9) intersects the bottom portion (8) in a state where the resin near the both seal portions is heat-welded to form a thick portion (11). A blow-molded container made of a synthetic resin, wherein a blow-shaped container is formed. The blow-molded container according to claim 1, wherein a crossing angle between the first seal portion (9) and the second seal portion (10) is approximately 90 °, and a cross-shaped seal portion is formed on the bottom portion (8). The blow-molded container according to claim 1 or 2, wherein an adhesive band (4) for adhering and fixing the outer layer (2) and the inner layer (3) is formed over the entire height range. In forming a multilayer parison (21) formed of at least a cylindrical outer layer (2) and a cylindrical inner layer (3), the parison (21) is divided below a die (22) by a parting line (25). A second sealing portion (10) is formed by sealing in a strip shape in a direction at a predetermined angle with respect to the direction, and the second sealing portion (10) is a bottom pinch-off portion (27) of the split mold (26). At the point immediately above the second seal portion (10), the portion immediately below the second seal portion (10) is pinched off with a split mold (26) and blow-molded.

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