JP5933367B2 - Flat bottle preform and flat bottle manufacturing method - Google Patents

Description

  The present invention relates to a preform for a flat bottle and a method for producing the flat bottle.

  Conventionally, for example, a flat bottle having a flat shape in a cross-sectional view having a major axis and a minor axis orthogonal to each other on a bottle axis as shown in Patent Document 1 below is known. Such a flat bottle has a bottomed cylindrical shape having a mouth, a shoulder, a trunk, and a bottom. For example, a bottomed cylindrical preform as shown in Patent Document 2 below is used as a mold. It is formed by biaxial stretch blow molding in the cavity of the apparatus.

Japanese Patent No. 4823587 JP2011-815A

  However, when a flat bottle is formed by blow-molding the conventional preform described above, the portion located on the minor axis in the bottom of the flat bottle after molding is more in the bottle radial direction than the portion located on the major axis. Since the amount of stretching was small, there was a risk of thickening.

  This invention is made in view of such a situation, Comprising: The flat bottle preform which can suppress the dispersion | variation in the thickness of the bottom part in the flat bottle after blow molding, and the manufacturing method of a flat bottle are provided. The purpose is that.

In order to solve the above problems, the present invention proposes the following means.
The present invention relates to a flat bottle preform for forming, by blow molding, a flat bottle having a flat shape in cross-sectional view having a major axis and a minor axis perpendicular to each other on the bottle axis. Of the bottom part of this preform corresponding to the bottom part, the thickness of the part on the short axis upper part forming part where the part located on the short axis of the flat bottle is formed is the part located on the long axis of the flat bottle The cut-out surface is formed in the short-axis upper portion formation planned portion of the outer peripheral surface of the preform, and the cut-out surface is formed on the preform. The outer peripheral surface is retracted radially inward from a portion other than the notch surface .
The present invention also relates to a method for producing a flat bottle, which is formed by blow-molding a flat bottle having a flat shape in a cross-sectional view having a major axis and a minor axis perpendicular to each other on the bottle axis. Of the bottom of the preform corresponding to the bottom of the flat bottle, the thickness of the portion on the short axis portion where the portion located on the short axis of the flat bottle is formed is positioned on the long axis of the flat bottle. portion is thinner than the thickness of the long axial portion forming scheduled portion formed, on said minor axis portion forming scheduled portion of the outer peripheral surface of said preform to form a cut edge, the notch surface, the The preform is blow-molded by retreating inward in the radial direction from a portion other than the notch surface on the outer peripheral surface of the preform.

  According to the preform for a flat bottle and the method for producing a flat bottle of the present invention, the thickness of the portion on which the short-axis upper portion is to be formed out of the bottom of the preform corresponding to the bottom of the flat bottle to be molded is Since the thickness is smaller than the thickness of the portion to be partially formed, it is possible to suppress variations in the thickness of the bottom portion of the flat bottle formed by blow-molding this preform in the circumferential direction of the bottle. Therefore, for example, it is possible to avoid a situation in which, for example, shrinkage (deformation) occurs at the bottom of the flat bottle after blow molding or appearance quality cannot be ensured. In addition, the material cost can be reduced since the portion on which the short-axis upper portion of the preform is to be formed can be made thin.

  As in the prior art, for example, when the thickness of the bottom portion of the preform is the same between the portion on which the short-axis upper portion is to be formed and the portion on which the long-axis upper portion is to be formed, in blow molding, the portion on which the long-axis upper portion is to be formed Since the stretch amount of the portion on which the short-axis upper part is to be formed is reduced, the thickness of the portion located on the short axis of the bottom of the flat bottle becomes thicker than that of the portion located on the long axis. May occur, appearance quality may not be stable, and desired heat resistance and rigidity may not be ensured.

  Further, in the flat bottle preform of the present invention, the engaging portion provided in the mold apparatus may be engaged to form a positioning portion that determines a circumferential position around the preform axis with respect to the cavity. Good.

  In this case, since the positioning portion is formed in the preform, when the preform is set in the cavity, the engagement portion is engaged with the positioning portion, so that the pre-formation portion on the short axis portion of the preform is formed. Can be directed in the minor axis direction in the cavity, and the portion on the major axis of the preform to be formed is directed in the major axis direction in the cavity. Therefore, it is possible to easily and accurately determine the circumferential position of the preform around the preform axis with respect to the cavity, and the flat bottle blow-molded using this preform has the above-described effects stably. Become.

  Further, in the flat bottle preform of the present invention, the positioning portion may be formed in a mouth portion of the preform disposed outside the cavity.

  In this case, since the positioning portion is formed in the mouth portion which is harder at a lower temperature than other portions during blow molding of the preform, the positioning portion is deformed when the engaging portion is engaged with the positioning portion. Can be suppressed, and the above-described effects can be reliably achieved with good reproducibility.

  According to the flat bottle preform and the flat bottle manufacturing method according to the present invention, it is possible to suppress variations in the thickness of the bottom of the flat bottle after blow molding.

It is a side view which shows the flat bottle which concerns on one Embodiment of this invention. It is a cross-sectional view of the flat bottle of FIG. It is the (a) side view of the preform for forming the flat bottle of FIG. 1 by blow molding, (b) The longitudinal cross-sectional view which shows the principal part, (c) The cross-sectional view which shows the principal part. FIG. 4 is a top view of the preform of FIG. 3. It is a figure explaining the state which set the preform of FIG. 3 in the cavity of a metal mold apparatus. 4A is a side view of a modified example of the preform of FIG. 3, FIG. 4B is a longitudinal cross-sectional view showing the main part, and FIG. 4C is a cross-sectional view showing the main part. It is a bottom view of the preform of FIG.

Hereinafter, the flat bottle 1 which concerns on one Embodiment of this invention is demonstrated with reference to drawings.
The flat bottle 1 of the present embodiment is formed of a synthetic resin material such as polyethylene terephthalate (PET), has a bottomed cylindrical shape as shown in FIGS. 1 and 2, and is orthogonal to each other on the bottle axis O. The cross-sectional view has a flat shape having a major axis L and a minor axis S.

In FIG. 1, a flat bottle 1 is a blow molded product formed by biaxial stretching blow molding of a bottomed cylindrical preform 10 (see FIG. 3) formed by injection molding, and along a bottle axis O. The mouth part 2, the shoulder part 3, the trunk part 4, and the bottom part 5 are integrally formed. In the present embodiment, out of the mouth portion 2, the shoulder portion 3, the trunk portion 4 and the bottom portion 5, the shoulder portion 3, the trunk portion 4 and the bottom portion 5 are respectively a long axis L and a short axis which are orthogonal to each other on the bottle axis O. It has an elliptical shape with a flat cross-sectional view having S.
In addition, the center axis of these mouth part 2, shoulder part 3, trunk | drum 4, and bottom part 5 is arrange | positioned on the common axis. In the present embodiment, this common axis is called a bottle axis O, the mouth 2 side along the bottle axis O direction is called the upper side, and the bottom 5 side is called the lower side. A direction perpendicular to the bottle axis O is referred to as a radial direction, and a direction around the bottle axis O is referred to as a circumferential direction.

  1 and 2, the mouth portion 2 has a circular cylindrical shape in cross-sectional view perpendicular to the bottle axis O, and the shoulder portion 3 other than the mouth portion 2 of the flat bottle 1, the trunk portion 4, and The diameter is smaller than the bottom 5. The opening of the mouth 2 is a spout for pouring the contents of the flat bottle 1.

A male screw portion 2 a is formed on the outer peripheral surface of the mouth portion 2. A part of the male screw portion 2a in the circumferential direction is notched, and this portion is positioned in the positioning portion 6 (bottle for engagement with an engaging portion provided in the mold apparatus 20 when the preform 10 is blow-molded. A notch in the direction of the axis O).
The male screw part 2a of the mouth part 2 is adapted to be screwed with a female screw part in a cap-shaped cylindrical cap (not shown), whereby the cap is detachably attached to the mouth part 2, The spout of the mouth 2 is sealed.

A lower end portion of the mouth portion 2 that is continuous with the shoulder portion 3 is a cylindrical neck portion 2b.
An annular neck ring 2c that protrudes radially outward and extends in the circumferential direction is formed between the male screw portion 2a and the neck portion 2b in the outer peripheral surface of the mouth portion 2.

  The shoulder 3 has a cylindrical shape with an elliptical cross-sectional view, and gradually increases in diameter from the mouth 2 toward the body 4. The lower end portion of the shoulder portion 3 is formed so as to protrude outward in the radial direction from the trunk portion 4.

  The body 4 has a cylindrical shape with an elliptical cross-sectional view, and an annular groove 4a that is recessed inward in the radial direction and extends along the circumferential direction is formed on the outer peripheral surface of the body 4. A plurality are formed at intervals in the direction.

The bottom 5 has a bottomed cylindrical shape with an elliptical cross-sectional view, and has a peripheral wall 5a and a bottom wall 5b. The peripheral wall 5a is formed so as to protrude radially outward from the body portion 4, and an annular groove 5c that is recessed radially inward and extends along the peripheral direction is formed on the outer peripheral surface of the peripheral wall 5a. A plurality are formed at intervals in the direction.
In the illustrated example, the arrangement interval between the groove portions 5 c adjacent to each other in the bottle axis O direction in the bottom portion 5 is smaller than the arrangement interval between the groove portions 4 a adjacent to each other in the bottle axis O direction in the body portion 4. Further, the groove depth of the groove portion 5 c of the bottom portion 5 is smaller than the groove depth of the groove portion 4 a of the trunk portion 4.

  Further, the surface facing the lower side of the bottom wall 5 b of the bottom portion 5 is a seating surface of the flat bottle 1. The center portion of the bottom wall 5b is recessed upward from the outer peripheral edge portion around the center portion.

Next, the preform 10 of the flat bottle 1 and the manufacturing method of the flat bottle 1 will be described.
The method for manufacturing the flat bottle 1 includes a blow molding process in which a bottomed cylindrical preform 10 is biaxially stretch blow molded. Further, the central axis (preform axis) of the preform 10 is coaxial with the bottle axis O of the flat bottle 1 formed by blow-molding the preform 10.

  As shown in FIGS. 3 to 5, the preform 10 of the flat bottle 1 includes a mouth portion 2 corresponding to the mouth portion 2 of the flat bottle 1 to be molded, and a shoulder portion 3 and a trunk of the flat bottle 1 to be molded. A body portion 11 corresponding to the portion 4 and a bottom portion 12 corresponding to the bottom portion 5 of the flat bottle 1 to be molded are provided. In the illustrated example, the outer diameter dimensions of the neck portion 2b, the trunk portion 11, and the bottom portion 12 in the mouth portion 2 of the preform 10 are substantially the same.

  In FIG. 5, when the preform 10 is blow-molded, the portion other than the neck portion 2b of the mouth portion 2 is disposed outside the cavity 22 of the cavity die 21 in the die device 20, and the neck portion 2b, the body portion 11 and the bottom 12 are disposed in the cavity 22. The shape of the cavity 22 of the cavity mold 21 is formed corresponding to the outer shape of the flat bottle 1.

Further, at the time of blow molding, an engaging portion (not shown) provided in the mold apparatus 20 is engaged with the positioning portion 6 of the mouth portion 2. The circumferential position around the preform axis O with respect to 22 is determined. The engaging portion includes, for example, a preform supply device that supplies the preform 10 to the cavity mold 21, a fixture for the mouth 2 provided in the cavity mold 21, a nozzle of an air blow (air supply) device, and the like. It can be variously arranged in the mold apparatus 20.
Moreover, as FIG.1 and FIG.3 shows, the shape of the opening part 2 does not change substantially before and after blow molding (the preform 10 and the flat bottle 1).

The body portion 11 of the preform 10 has a cylindrical shape with a circular cross-sectional view, and extends in parallel to the preform axis O.
The bottom portion 12 of the preform 10 has a bottomed cylindrical shape with a circular cross-sectional view, and has a dome shape that is convex downward.

  3 and 5, the thickness of the short-axis upper portion formation planned portion 12 a in which the portion located on the short axis S of the flat bottle 1 is formed in the bottom portion 12 of the preform 10 is the flat bottle 1. It is made thinner than the wall thickness of the long-axis upper part formation scheduled part 12b in which the part located on the long axis L is formed. That is, in the manufacturing method of the flat bottle 1, the thickness of the short-axis upper portion formation planned portion 12a of the bottom portion 12 of the preform 10 is made smaller than the thickness of the long-axis upper portion formation planned portion 12b, The preform 10 is blow molded.

  In a side view of the preform 10 shown in FIG. 3A, a circular notch surface 13 is formed on the short-axis upper portion formation scheduled portion 12 a of the outer peripheral surface of the preform 10. A pair of cut-out surfaces 13 are formed on at least the bottom 12 of the preform 10 with the preform axis O sandwiched between them. In the illustrated example, the cut-out surfaces 13 extend from the bottom 12 to the lower end of the body 11. Is formed.

  The notch surface 13 is retreated inward in the radial direction from a portion other than the notch surface 13 on the outer peripheral surface of the preform 10, whereby the short-axis on-axis portion formation planned portion on which the notch surface 13 is disposed. The wall thickness of 12a is thinner than the wall thickness of the long axis upper part formation scheduled portion 12b.

  In a longitudinal sectional view along the preform axis O shown in FIG. 3B, the cut-out surface 13 is gradually inclined inward in the radial direction as it goes downward. In the example shown in FIGS. 3B and 3C, the cutout surface 13 has a flat shape. Instead, the cutout surface 13 is formed on the outer peripheral surface of the bottom portion 12. A convex curved surface having a larger radius of curvature than other portions may be formed.

  Although not particularly illustrated, the preform 10 having such a configuration forms the outer shape (outer peripheral surface) of the preform 10 among the cavity mold and the core mold used when the preform 10 is injection-molded. By forming the planar portion corresponding to the notch surface 13 on the inner peripheral surface of the cavity mold so as to protrude from other portions, it can be easily molded.

  According to the preform 10 of the flat bottle 1 and the manufacturing method of the flat bottle 1 of the present embodiment described above, the short-axis upper portion of the bottom portion 12 of the preform 10 corresponding to the bottom portion 5 of the flat bottle 1 to be molded. Since the thickness of the planned formation portion 12a is thinner than the thickness of the long-axis upper portion formation planned portion 12b, the thickness of the bottom portion 5 of the flat bottle 1 formed by blow molding this preform 10 is Variation in direction can be suppressed. Therefore, it is possible to avoid a situation in which, for example, the bottom portion 5 of the flat bottle 1 after blow molding is closed (deformed) or appearance quality cannot be ensured. Moreover, since the short axis upper part formation scheduled portion 12a of the preform 10 can be made thin, the material cost can be reduced.

  As in the prior art, for example, when the thickness of the bottom portion of the preform is the same between the portion on which the short-axis upper portion is to be formed and the portion on which the long-axis upper portion is to be formed, in blow molding, the portion on which the long-axis upper portion is to be formed Since the stretch amount of the portion on which the short-axis upper part is to be formed is reduced, the thickness of the portion located on the short axis of the bottom of the flat bottle becomes thicker than that of the portion located on the long axis. May occur, appearance quality may not be stable, and desired heat resistance and rigidity may not be ensured.

  Further, since the positioning portion 6 that is engaged with the engaging portion of the mold apparatus 20 is formed in the preform 10, when the preform 10 is set in the cavity 22, the engaging portion is positioned in the positioning portion 6. Is engaged with the short axis direction portion 12a of the preform 10 in the short axis direction (direction perpendicular to the paper surface in FIG. 5) in the cavity 22, and the long axis upper portion of the preform 10 is formed. The formation planned portion 12b can be oriented in the long axis L direction (the left-right direction in FIG. 5) in the cavity 22. Therefore, the circumferential direction position of the preform 10 around the preform axis O with respect to the cavity 22 can be easily determined with high accuracy, and the flat bottle 1 blow-molded using the preform 10 can be stably described above. There will be an effect.

  Further, since the positioning portion 6 is formed in the mouth portion 2 which is harder at a lower temperature than other portions of the preform 10 at the time of blow molding, the positioning portion 6 is positioned when the engaging portion is engaged with the positioning portion 6. It is possible to suppress the deformation of the portion 6, and the above-described effects can be reliably achieved with good reproducibility.

  Further, in the present embodiment, by forming the notch surface 13 on the outer peripheral surface of the preform 10, the short-axis upper portion formation planned portion 12a in the bottom portion 12 of the preform 10 can be easily formed thin, and The short axis upper part formation scheduled portion 12a can be visually confirmed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the cross-sectional view shape of the shoulder portion 3, the body portion 4, and the bottom portion 5 of the flat bottle 1 is an elliptical shape, but is not limited thereto. That is, the flat bottle 1 only has to have a long axis L and a short axis S orthogonal to each other on the bottle axis O, as long as the cross-sectional view shape thereof is a flat shape. An oval shape other than an elliptical shape, a polygonal shape, a shape in which both ends of the major axis of the ellipse are chamfered, or the like may be used. In this case, the long longitudinal direction in the cross sectional view of the flat bottle 1 means the long axis L, and the short short direction means the short axis S.

Moreover, in the above-mentioned embodiment, although the circumferential direction part of the external thread part 2a of the opening | mouth part 2 was notched and the positioning part 6 was formed, it is not limited to this. Specifically, instead of forming the positioning portion 6 in the male screw portion 2a of the mouth portion 2, for example, a part of the neck ring 2c of the mouth portion 2 in the circumferential direction may be cut out to form the positioning portion.
Moreover, you may use the notch surface 13 formed in the outer peripheral surface of the preform 10 as a positioning part instead of forming a positioning part in the opening part 2. FIG. In this case, a contact surface that engages the notch surface 13 with a receiving rod that sandwiches the bottom portion 12 of the preform 10 together with the stretching rod from the thickness direction during blow molding and moves in the cavity 22 in the direction of the preform axis O. The corresponding contact surface may be used as the engaging portion of the mold apparatus 20.

In addition, the short axis upper portion formation planned portion 12a of the preform 10 has a notch for making the thickness of the short axis upper portion formation planned portion 12a thinner than the thickness of the long axis upper portion formation planned portion 12b. Although the surface 13 is formed, the shape of the cut-out surface 13 is not limited to that described above.
Here, what is shown in FIGS. 6 and 7 is a modification of the preform 10 described in the above-described embodiment. In this modification, instead of using the circular cut-out surface 13 described above, an oval cut-out surface 14 is formed on the short-axis upper part formation planned portion 12 a of the outer peripheral surface of the preform 10. In the illustrated example, the notch surface 14 is formed only on the bottom portion 12 of the preform 10 so that the major axis of the ellipse extends in the circumferential direction. Further, the notch surface 14 has a convex curved surface with a larger radius of curvature than a portion other than the notch surface 14 on the outer peripheral surface of the bottom portion 12 of the preform 10.

Further, in a reference example having a technical idea different from that of the present invention, the notch surfaces 13 and 14 are not formed, and the thickness of the short-axis upper portion formation planned portion 12a of the preform 10 is set to the long-axis upper portion formation planned portion. It may be thinner than the thickness of 12b. Specifically, instead of forming the notched surfaces 13 and 14 on the outer peripheral surface of the preform 10, for example, the long-axis upper portion formation planned portion 12b is added to the short-axis upper portion formation planned portion 12a on the inner peripheral surface of the preform 10. By forming a more depressed recess, the thickness of the short-axis upper portion formation planned portion 12a may be thinner than the long-axis upper portion formation planned portion 12b.

Further, since the thickness of the short axis portion forming scheduled portion 12a of the preform 10, if it is thinner than the thickness of the long axial portion forming scheduled portion 12b, work for effect is obtained, in the reference example, As described above, instead of reducing the thickness of the short-axis upper portion formation planned portion 12a by the notch surfaces 13 and 14 and the concave portion, the long-axis upper portion formation planned portion 12b may be increased in thickness. . In this case, at least one of the inner peripheral surface and the outer peripheral surface of the long-axis upper part formation scheduled portion 12b of the preform 10 is projected from the other part.
Specifically, for example, on the long axis on the outer peripheral surface of the core mold that molds the inner shape (inner peripheral surface) shape of the preform 10 among the cavity mold and the core mold used when the preform 10 is injection molded. A receding part that is receded from other parts of the outer peripheral surface is formed at a part corresponding to the part formation scheduled part 12b. Thereby, the long-axis upper part formation scheduled part 12b of the inner peripheral surface of the preform 10 to be injection-molded can be protruded from the short-axis upper part formation scheduled part 12a. Can be formed thicker than the short axis upper part formation scheduled portion 12a.

  Moreover, although the above-mentioned embodiment demonstrated the example using the screw cap with which a cap is detachably mounted | worn with the opening part 2 of the flat bottle 1 by screwing, it is not limited to this, For example, Further, a stopper cap in which the cap is detachably attached to the mouth portion 2 by undercut fitting or the like may be used. In addition, a dispenser such as a pump may be attached to the mouth portion 2 instead of the cap.

  In addition, it is possible to appropriately replace the constituent elements in the above-described embodiments with well-known constituent elements without departing from the spirit of the present invention, and the above-described modified examples may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 Flat bottle 2 Mouth part 5 Flat part bottom part 6 Positioning part 10 Preform 12 Preform bottom part 12a Short-axis upper part formation scheduled part 12b Long-axis upper part formation scheduled part 13, 14 Notch surface (positioning part)
20 Mold device 22 Cavity L Long axis O Bottle axis, Preform axis S Short axis

Claims (4)

A flat bottle preform for forming a flat bottle in a cross-sectional view flat shape having a major axis and a minor axis perpendicular to each other on the bottle axis by blow molding,
Of the bottom of this preform corresponding to the bottom of the flat bottle to be molded, the thickness of the portion on the short axis on which the portion located on the short axis of the flat bottle is formed is on the long axis of the flat bottle. The portion on the long axis on which the portion located at is formed is thinner than the thickness of the portion to be formed ,
A notch surface is formed in the short-axis upper part formation planned portion of the outer peripheral surface of the preform,
The flat bottle preform characterized in that the notch surface is retreated inward in the radial direction from a portion other than the notch surface on the outer peripheral surface of the preform. The flat bottle preform according to claim 1,
A flat bottle preform characterized in that a positioning part for determining a circumferential position around a preform axis with respect to a cavity is formed by engaging an engaging part provided in a mold apparatus. A flat bottle preform according to claim 2,
The flat bottle preform is characterized in that the positioning portion is formed in a mouth portion of a preform arranged outside the cavity. A flat bottle manufacturing method for forming a flat bottle in a cross-sectional view flat shape having a major axis and a minor axis orthogonal to each other on a bottle axis by blow molding a preform,
Of the bottom part of the preform corresponding to the bottom part of the flat bottle to be molded, the thickness of the part on the short axis upper part forming part where the part located on the short axis of the flat bottle is formed is indicated on the long axis of the flat bottle. thinner than the thickness of the long axial portion forming scheduled portion of a portion located is formed,
Forming a notch surface in the short axis upper part formation planned portion of the outer peripheral surface of the preform,
A method for producing a flat bottle , wherein the notched surface is retracted radially inward from a portion other than the notched surface on the outer peripheral surface of the preform , and the preform is blow-molded.

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