JP2018016344A - Synthetic resin container, and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently mold a bottom shape provided with a depressed recessed part in an excellent shaping property, in a stackable synthetic resin container which enables vertically stacking two or more containers by providing in a container bottom a depressed recessed part into which a mouth part side of the other container can be inserted.SOLUTION: A synthetic resin container is such that: a depressed recessed part 51 provided in a bottom 5 has a base part 52 erected along an inner peripheral edge of a grounding part 50 of the bottom 5, and a lid body engagement part 53 which is reduced in a diameter concentrically to the base part 52, and with which a lid body 6 mounted on a mouth 2 of the other container 1 is engaged in a loosely engaging state; and the base part 52 and the lid body engagement part 53 are formed to be connected via a step part 54.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stackable synthetic resin container and a method for manufacturing the same.

  Conventionally, a synthetic resin container formed by forming a bottomed cylindrical preform using a thermoplastic resin such as polyethylene terephthalate, and then molding the preform into a bottle shape by biaxial stretch blow molding or the like, It is generally used in a wide field as a container containing various beverages and various seasonings.

  In addition, regarding this type of synthetic resin container, stackable parts (stackable) in which two or more containers can be stacked one above the other by providing a recessed part on the bottom of the container that can be inserted into the mouth of another container. A known container is known (see Patent Document 1).

JP 2014-125236 A

  However, in such a stackable container, the depressed recess provided in the bottom of the container has a shape greatly depressed inward of the container to the extent that it can cover the mouth side of the inserted container. Yes. Therefore, at the time of blow molding, for example, as shown in FIG. 10, the bottom mold BMp1 that molds the depressed recess is hindered from extending the preform PF, and the part that molds the ground contact portion of the container bottom in the mold There is a problem that the preform PF is not stretched to CG and the grounding portion cannot be formed. Such a problem is particularly conspicuous in a container in which the recessed portion occupies a large proportion and the area of the ground contact portion is small with respect to the entire area of the bottom.

  In order to solve such a problem, for example, as shown in FIG. 11, it is conceivable to make the bottom mold BMp <b> 2 that molds the depressed concave portion movable. That is, after extending the preform PF until reaching the bottom mold BMp2 located at the bottom dead center beyond the part CG forming the ground contact portion at the bottom of the mold, the bottom mold BMp2 is raised to the top dead center. Thus, it is conceivable to shape the bottom shape provided with the depressed recess by reversing the portion extended beyond the portion CG while pushing it back.

However, in this case, the portion extended beyond the portion CG for forming the ground contact portion at the bottom of the mold has a length sufficient as an inversion allowance for reversing it and forming the depressed recess. , depending on the depth of the depression recess, it is necessary to increase the stroke S ₀ of the bottom type BMP2, for that purpose, leads to enlargement of the apparatus, its formation is not capable of easily.

Accordingly, as shown in FIG. 12, the present inventors expand the diameter of the bottom mold insertion portion, and form a space in which the stretched preform can enter between the inner peripheral surface and the bottom mold MBp3. Thus, an investigation was made on the assumption that a sufficiently long inversion allowance could be secured for the stretched preform without increasing the stroke S1 of the bottom BMp3.
However, in this case, since the leading end side of the stretched preform is in a free state, if there is a slight unevenness in the preform, there is a risk that the stretch may be excessive or insufficient. If the stretching is insufficient, the reversal allowance cannot be ensured, resulting in poor shaping, and if the stretching is excessive, there is a problem that burrs are generated due to the surplus when reversing.

  The present invention has been made in view of the circumstances as described above, and is provided with a recessed recess that can be inserted on the mouth side of another container at the bottom of the container so that two or more containers can be stacked vertically. It is an object of the present invention to provide a stackable synthetic resin container in which a bottom shape provided with a depressed recess is formed with good shapeability and a manufacturing method thereof.

  The synthetic resin container according to the present invention includes a mouth, a shoulder, a trunk, and a bottom, and the bottom is provided with a depressed recess that allows insertion of the mouth of the other container. A container made of a synthetic resin that can be stacked up and down, wherein the depressed recess is reduced in diameter concentrically with respect to the base that rises along the inner periphery of the grounding portion of the bottom, As a configuration in which the lid mounted on the mouth of the other container has a lid insertion portion that fits in a loose fit, and the base and the lid insertion portion are connected via a stepped portion. is there.

  The synthetic resin container manufacturing method according to the present invention is the above-described synthetic resin container manufacturing method, wherein the bottom mold having a shape corresponding to the depressed recess forms the grounding portion in the mold. Blow molding is inserted into the bottom mold insertion part drilled along the inner peripheral edge of the mold so as to be able to move up and down, and blow molding is started with the bottom mold waiting at the bottom dead center. This is a method of raising the mold to the top dead center and completing blow molding.

  According to the synthetic resin container according to the present invention, the stackable synthetic resin container in which the bottom shape provided with the recessed concave portion in which the mouth side of the other container can be inserted is formed with good shapeability is provided. Can be provided.

  In addition, according to the method for manufacturing a synthetic resin container according to the present invention, it is possible to secure a sufficient length inversion allowance without increasing the bottom mold stroke, and further, Since the tip side is regulated by the bottom mold step part, it is possible to prevent excess or deficiency in the extension of the part that becomes the reversal allowance, and the bottom part provided with the recessed part of the synthetic resin container This shape can be molded well with good formability.

It is a front view showing an outline of one embodiment of a synthetic resin container according to the present invention. It is explanatory drawing which shows an example of the manufacturing method of the synthetic resin containers based on this invention. FIG. 3 is an enlarged view of a main part of FIG. 2. It is explanatory drawing which shows an example of the manufacturing method of the synthetic resin containers based on this invention. It is explanatory drawing which shows an example of the manufacturing method of the synthetic resin containers based on this invention. It is explanatory drawing which shows in perspective an example of the bottom mold | type of the blow molding die used for embodiment of this invention. It is explanatory drawing which perspectively shows and shows the other example of the bottom mold | type of the blow mold used for embodiment of this invention. It is explanatory drawing which perspectively shows and shows the other example of the bottom mold | type of the blow mold used for embodiment of this invention. It is a front view which shows the outline of the modification of one Embodiment of the synthetic resin containers which concern on this invention. It is explanatory drawing which shows an example of a prior art. It is explanatory drawing which shows the other example of a prior art. It is explanatory drawing which shows the example of examination of the manufacturing method of a synthetic resin container.

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

  A container 1 according to the present invention includes a mouth part 2, a shoulder part 3, a trunk part 4, and a bottom part 5. In the container 1 illustrated as an embodiment of the present invention, the trunk part 4 is formed in a cylindrical shape. In general, it has a container shape called a round bottle.

  Such a container 1 uses a thermoplastic resin to form a bottomed cylindrical preform by injection molding, compression molding, or the like, and the preform is molded into a predetermined container shape by biaxial stretch blow molding or the like. Manufactured by.

  In producing the container 1, as the thermoplastic resin to be used, any resin capable of blow molding can be used. Specifically, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, amorphous polyarylate, thermoplastic polyester such as polylactic acid or copolymers thereof, those blended with these resins or other resins, etc. are suitable. It is. In particular, an ethylene terephthalate thermoplastic polyester such as polyethylene terephthalate is preferably used. Also, polycarbonate, acrylonitrile resin, polypropylene, propylene-ethylene copolymer, polyethylene and the like can be used.

The mouth portion 2 is a cylindrical portion serving as a content outlet, and a lid body 6 that seals the inside of the container is attached to the mouth portion 2.
In FIG. 1, a part of the lid 6 is cut away.

  Further, the lower end of the mouth portion 2 expands toward the body portion 4 and is connected to the shoulder portion 3 connecting the mouth portion 2 and the body portion 4. In the illustrated example, the shoulder portion 3 has a conical shape. It is formed in a trapezoid shape.

  The body 4 is a part that occupies most of the height direction of the container 1, and has an upper end connected to the shoulder 3 and a lower end connected to the bottom 5. Although not particularly shown, the body 4 is filled with a so-called hot pack and sealed, and then has a reduced pressure absorption panel that absorbs the pressure decrease in the container cooled to room temperature, and has a lateral load resistance strength. An annular transverse groove or the like for raising can be provided as necessary.

  Here, the height direction means a direction orthogonal to the horizontal plane when the container 1 is erected on the horizontal plane with the mouth portion 2 up, and in this state, the vertical, horizontal, vertical and horizontal directions of the container 1 are defined. Shall be defined. The same applies to the blow mold 100 for molding the container 1, and the direction thereof is defined in accordance with the container 1 to be molded.

  Further, the bottom 5 has a grounding portion 50 for allowing the container 1 to stand by itself in contact with the horizontal plane when the container 1 is set upright on the horizontal plane. It is connected to the lower end of the body part 4 while being bent obliquely upward along the outer peripheral edge of the part 50. In the illustrated example, the grounding portion 50 is formed so as to extend annularly along the circumferential direction, but the specific shape is not limited as long as the container 1 can stand on its own.

  Further, the bottom portion 5 is provided with a depressed concave portion 51 whose center portion is depressed inward of the container so that the mouth portion 2 side of the other container 1 can be inserted. By providing such a depressed recess 51, the container 1 is configured such that two or more containers 1 are stacked one above the other as shown in FIG.

  The depressed recess 51 has a base 52 that rises along the inner peripheral edge of the ground contact portion 50, and a diameter that is concentrically reduced with respect to the base 52, so that the lid 6 attached to the mouth 2 of the other container 1 is free to play. It has the cover body insertion part 53 inserted in fitting shape, and the base 52 and the cover body insertion part 53 are connected via the step part 54. As shown in FIG.

  In the present embodiment, the lid insertion portion 53 is formed coaxially with the axis of the container 1 so that two or more containers 1 can be stacked on the same axis, and the shoulder 3 is stacked upward. It is preferable to provide an annular engagement portion 30 that engages with the periphery of the opening of the recessed recess 51 of the container 1. By doing in this way, the containers 1 can be stacked in a more stable state.

  In such a container 1, the bottom mold BM for molding the depressed recess 51 is made movable so that the shape of the bottom 5 provided with the depressed recess 51 that is greatly depressed inward of the container is formed with good shapeability. It can be manufactured using a blow mold 100 (see FIG. 2).

The blow molding die 100 is configured such that a bottom die BM is inserted into a bottom die insertion portion that is drilled in a vertical direction along an inner peripheral edge of a portion CG for molding the grounding portion 50 of the bottom 5 in the die. ing. The bottom mold BM has a sliding part BM0 that slides on the inner peripheral surface 101 of the bottom mold insertion part, and can be moved up and down in the vertical direction by a driving device (not shown). .
Further, the bottom mold BM has a shape corresponding to the recessed recess 51, and together with the sliding part BM0, a lid insertion part molding part BM53 for molding the lid insertion part 53 and a step part molding for molding the step part 54. A part BM54 and a base forming part BM52 for forming the base 52 are provided.

  In order to manufacture the container 1, first, as shown in FIG. 2, a preform PF that is heated and softened to be capable of blow molding is set, and the bottom mold BM is kept at the bottom dead center. In the state, the blow mold 100 is closed. Then, blow air is started by blowing blow air into the preform PF while lowering a drawing rod (not shown).

  At this time, the preform PF can be uniformly stretched by appropriately adjusting the lowering speed of the stretching rod, the pressure of the blow air, etc., exceeding the portion CG for molding the ground contact portion 50 of the bottom 5 in the mold. Thus, the preform PF is stretched until it reaches the bottom mold BM located at the bottom dead center, thereby forming a molding intermediate MM (see FIG. 4). Next, the bottom mold BM is raised to the top dead center, and the blow-molding is completed while the portion extended beyond the portion CG is reversed while being reversed. Thereby, the stretched preform PF is brought into close contact with the molding surface of the blow mold 100, and the shape is shaped (see FIG. 5).

  In manufacturing the container 1 in this way, in this embodiment, the front end side of the preform PF stretched by blow molding is inserted into the inner peripheral surface 101 of the bottom mold insertion portion and the lid of the bottom mold BM. A portion that extends into the space surrounded by the part molding part BM53 and the step part molding part BM54 of the bottom mold BM (see FIG. 4) and extends beyond the part CG for molding the grounding part 50 of the bottom part 5 in the mold. However, this can be reversed so that the length of the reversal for forming the depressed recess 51 is sufficient. For this reason, it is possible to ensure a sufficiently long reversal allowance without increasing the stroke S of the bottom mold BM. Furthermore, according to the present embodiment, since the leading end side of the stretched preform is regulated by the step forming portion BM54 of the bottom mold BM, it is ensured that there is no excess or deficiency in the stretching of the portion serving as the inversion allowance. It is also possible, and the shape of the bottom portion 5 provided with the depressed recess 51 can be formed well with good formability.

Further, in order to be able to better shape the shape of the bottom portion 5 provided with the depressed concave portion 51 with good formability, the step portion forming portion BM54 is formed when the bottom mold BM is located at the bottom dead center. It is preferable that the distance along the height direction from the part CG for molding the ground contact portion 50 of the bottom portion 5 in the mold to the step forming portion BM54 is at a position equal to the height H of the base forming portion BM52. That is, the stroke S of the bottom mold BM is preferably twice the height H of the base molding part BM52. Furthermore, it is preferable that the height h from the lower end part of the base molding part BM52 to the upper end part of the lid insertion part molding part BM53 is 20 mm or more.
In addition, it is preferable that the side surface of the lid insertion portion molding portion BM53 and the side surface of the base portion molding portion BM52 are tapered surfaces in consideration of the draft. Moreover, it is preferable to attach R to the lid insertion part molding part BM53 side of the step part molding part BM54 in consideration of shaping.

Further, the lid insertion part molding part BM53 has a vertical plane including the axis of the bottom mold BM and a horizontal plane including the inner peripheral surface 101 of the bottom mold insertion part and the edge part of the step molding part BM54 of the bottom mold BM. The three-point inscribed circle iC that is in contact with the side surface of the lid fitting portion molding part BM53 of the bottom mold BM is preferably formed to have a curvature radius of 5 or more (see FIG. 3).
Note that FIG. 3 is an enlarged view of the main part showing the portion surrounded by the one-dot chain line in FIG. 2 in an enlarged manner.

  By doing in this way, it can suppress that the front-end | tip shape of the stretched preform PF which reached | attained the step part shaping | molding part BM54 becomes uneven along the circumferential direction. As a result, the molding intermediate MM can be stably molded with high reproducibility, and the formability in blow molding can be improved.

  As a result, the container 1 finally manufactured through blow molding has a vertical plane including the axis thereof, a vertical line passing through the inner peripheral edge of the ground contact portion 50, a horizontal plane including the edge portion of the step portion 54, a lid The three-point inscribed circle in contact with the side surface of the body fitting portion 53 is formed so that the radius of curvature is 5 or more, and the shape of the bottom portion 5 is well molded with good shapeability.

  Further, when the bottom mold BM is raised and the portion extended beyond the portion CG for forming the ground contact portion 50 at the bottom in the mold is reversed while being pushed back, the bottom mold is wound while the portion is wound inside the container. It is shaped into the BM and formed into the depressed recess 51. For this reason, the length (peripheral length) along the circumferential direction does not match, and wrinkles may occur in the formed recessed recess 51 due to the difference in the circumferential length before and after the reversal.

The bottom mold BM is preferably provided with an uneven shape for absorbing such a difference in circumferential length to suppress the generation of wrinkles or to make the bottom BM inconspicuous.
For example, as shown in FIG. 6, the concavo-convex shape is provided by forming a plurality of protrusions BM55 straddling the side surface of the lid insertion part forming part BM53 and the step part forming part BM54 along the circumferential direction. May be. In the container 1 formed using the bottom mold BM having such an uneven shape, a plurality of concave grooves straddling the side surface of the lid insertion portion 53 and the step portion 54 are provided in the recessed portion 51 along the circumferential direction. It is formed and remarkable wrinkle generation is suppressed.

  Further, the uneven shape provided in the bottom mold BM may be provided by forming a plurality of concave grooves BM56 along the circumferential direction on the side surface of the base molding part BM52 as shown in FIG. In the container 1 formed using the bottom mold BM provided with such a concave and convex shape, a plurality of ridges are formed along the circumferential direction on the side surface of the base 52 of the depressed concave portion 51 to suppress the occurrence of remarkable wrinkles. Will be.

  In addition, as shown in FIG. 8, it is possible to suppress the occurrence of significant wrinkles by partially cutting out the base molding part BM52 to provide an uneven shape, but in this case, the base molding part BM52 is partially It is preferable that a surface that is flush with the side surface of the lid insertion portion molding part BM53 appears in the notched portion BM57. By doing in this way, the recessed part 51 of the shape | molded container 1 is formed with the rib part 57 extended on the cover body insertion part 53 and the same plane (refer FIG. 9). Thereby, the opening part side of the other container 1 inserted in the depression recessed part 51 is supported by the rib part 57, and the container 1 can be stacked more stably. When setting it as such an aspect, it is preferable to form three or more the rib parts 57 at equal intervals along the circumferential direction.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. Nor.

  For example, in the above-described embodiment, the container 1 having a container shape called a round bottle is illustrated and described. However, the illustrated example is merely an embodiment of the present invention. The container shape to which the present invention is applied is not limited to that shown in the figure. The present invention has a technical feature in the shape of the depressed recess 51 provided in the bottom 5 in order to allow two or more containers 1 to be stacked one above the other. It can be changed as necessary.

  That is, according to the present invention, a recessed portion 51 provided in the bottom portion 5 has a base 52 that rises along the inner peripheral edge of the grounding portion 50 of the bottom portion 5 and a diameter that is concentrically reduced with respect to the base portion 52. If the lid body 6 attached to the one mouth portion 2 has a lid insertion portion 53 into which the lid body 6 is loosely fitted, and the base portion 52 and the lid body insertion portion 53 are connected via the step portion 54. The configuration of details other than this can be changed as appropriate without being limited to the above-described embodiment. Further, the detailed configurations described in the above-described embodiments can be appropriately selected and combined.

  The present invention can be widely used as a stackable synthetic resin container.

DESCRIPTION OF SYMBOLS 1 Container 2 Mouth part 3 Shoulder part 4 Trunk part 5 Bottom part 50 Grounding part 51 Recessed recessed part 52 Base part 53 Cover body insertion part 54 Step part 100 Blow molding die 101 Inner peripheral surface of bottom mold insertion part BM Bottom type BM0 Sliding part BM52 Base molding part BM53 Lid fitting part molding part BM54 Step molding part

Claims (8)

A composition comprising a mouth, a shoulder, a body, and a bottom, and a recessed recess that can be inserted into the mouth of another container is provided on the bottom so that two or more containers can be stacked one above the other. A resin container,
The depressed recess is
A base that rises along the inner periphery of the bottom grounding portion;
A lid fitting portion that is concentrically reduced in diameter with respect to the base portion, and a lid body fitted in a mouth portion of the other container is fitted in a loose fit,
The synthetic resin container, wherein the base and the lid insertion portion are connected via a stepped portion.   On the vertical plane including the container axis, the radius of curvature of a three-point inscribed circle that is in contact with the vertical line passing through the inner peripheral edge of the grounding portion, the horizontal plane including the edge portion of the stepped portion, and the side surface of the lid insertion portion The synthetic resin container according to claim 1, wherein R is 5 or more.   The synthetic resin container according to claim 1 or 2, wherein an annular engagement portion that engages with a peripheral edge of an opening of the depressed recess provided in a bottom portion of the other container is provided on the shoulder portion.   The synthetic resin container according to any one of claims 1 to 3, wherein a plurality of concave grooves straddling the side surface of the lid insertion portion and the stepped portion are formed in the depressed concave portion along a circumferential direction. .   The synthetic resin container according to any one of claims 1 to 3, wherein a plurality of ridges are formed along a circumferential direction on a side surface of the base of the depressed recess.   The synthetic resin container according to any one of claims 1 to 3, wherein a rib portion extending flush with the lid insertion portion is formed in the depressed recess. A method for producing a synthetic resin container according to any one of claims 1 to 6,
A bottom mold having a shape corresponding to the depressed recess uses a blow mold inserted through a bottom mold insertion portion drilled along an inner peripheral edge of a portion for molding the grounding portion in the mold,
Start blow molding with the bottom mold waiting at the bottom dead center,
Next, the synthetic resin container manufacturing method is characterized in that the bottom mold is raised to the top dead center to complete blow molding.   The bottom mold has a vertical plane including the axis of the bottom mold, an inner peripheral surface of the bottom mold insertion part, a horizontal plane including an edge part of a step part forming part for forming the step part, and the lid insertion The method for producing a synthetic resin container according to claim 7, wherein a radius of curvature R of a three-point inscribed circle that is in contact with a side surface of the lid insertion portion molding portion that molds the portion is 5 or more.