JP2018144874A - Square shape bottle made of thermoplastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disclose a square type bottle made of a thermoplastic having good self-supporting stability.SOLUTION: A square blow-molded bottle has a recessed part recessed upward at a center part of a bottom surface, and has a substantially horizontal part at a peripheral part of the recessed part. The horizontal part has a convex part protruding downward at a part thereof. When the bottle is erected on the horizontal surface, at least a part of the convex part contacts the horizontal surface and the position of the convex part on the bottom surface satisfies the following conditions (a) and (b). The condition (a): four intersections of one circle whose center is the center of the bottom surface and whose ratio of a circle diameter to the long side length of a substantially quadrangle is 0.70 or more and 1.0 or less and the diagonal line of the substantially quadrangle is included. The condition (b): eight intersections of one circle whose center is the center of the bottom surface and whose ratio of a circle diameter to the long side length of the substantially quadrangle is 0.70 or more and 1.0 or less and a straight line parallel to the four sides of the substantially quadrangle is included.SELECTED DRAWING: Figure 5

Description

  The present application discloses a square bottle made of a thermoplastic plastic having a substantially rectangular horizontal cross section.

A square bottle made of thermoplastic plastic is manufactured by heating a bottomed cylindrical parison (preform) and blow-drawing in a mold. For this reason, in the case of a plastic blow-molded bottle whose body section has a substantially square cross section, the corners are thicker and less stretched than the center of each side. As a result, the vicinity of the corner tends to be insufficiently cooled, the retained heat remains after removal from the mold, sink deformation occurs, the vicinity of the corner shrinks and rises, and the bottom center protrudes downward. Causes bottom problems.
In addition, the bottle partially undergoes heat shrinkage deformation due to external factors such as heat when filling the contents (incorrect deformation). Furthermore, when the substantially quadrangular shape is rectangular, the degree of stretching differs between the short side and the long side, so that it becomes more difficult to suppress the deformation.

In particular, when deformation occurs at the bottom, the grounding becomes unstable and the bottle's self-supporting stability is poor, preventing it from standing upright, causing the phenomenon of wobbling or tilting, and transporting, packing, and arranging the bottles before and after filling the contents. Malfunctions. In addition, the product value is lost due to poor appearance.
Above all, when a rocker bottom derived from sink deformation at the bottom occurs after taking out from the mold, the empty bottle before filling the contents is light only by its own weight, so it is prone to wobble and tilt of the bottle, and lacks self-supporting stability, There is a possibility that filling and injection of contents such as liquids cannot be performed normally.

  Regarding conventional square bottles, for example, in Patent Document 1, in order to reduce the amount of heat at the bottom for the purpose of preventing deformation of the bottom at the time of heating from the external environment such as heated sales of beverages, the bottom is recessed upward. The concave center portion (10) and the periphery thereof may be provided with a linear grounding portion (11), and a connecting portion (12) may be provided therebetween, or a partial linear grounding portion and a partial concave portion (13) may be provided. In addition, in order to improve the self-supporting stability, the place corresponding to the lower body part and the corner part is a straight line (11A, 11B), and the connection between the straight lines is a curve (11C), In order to improve the shapeability, it is disclosed that the vertical cross-sectional shape of the ground contact portion is a curved surface having a curvature radius of 0.3 mm to 5 mm.

However, in the technique of Patent Document 1, when the substantially square shape of the bottom surface increases in area and each side becomes longer, the difference in the degree of stretching increases between the corner and the center of each side. As a result, the center part of each side becomes a circular arc shape projecting downward, and only the center part of the side is grounded. As a matter of course, the bottle's self-supporting stability is poor, and a phenomenon of wobbling or tilting occurs.
Moreover, in the technique of patent document 1, since the concave center part (10), the connection part (12), and the earthing | grounding part (11) are provided concentrically centering on the bottom center part, a trunk | drum horizontal cross section is abbreviate | omitted. In the case of a substantially rectangular shape instead of a square shape, it is easy to fall down due to shaking in the long side direction.
Furthermore, all the bottom surface portions other than the grounding portion (11) are recessed in a concave shape or connected upward toward the trunk portion, and the load resistance is weak because the load is received only by the linear portion on the bottom surface.

  In order to suppress the occurrence of the above-mentioned sink deformation and rocker bottom deformation, a method of performing heat setting after blow molding in a mold and a method of strengthening cooling from the general conditions can be considered. The manufacturing cost increases due to the increased energy load and process time for temperature control and cooling. In particular, since a low cost is essential for a bottle for room temperature use, it is necessary to suppress the deformation of the bottom and stabilize the container upright while maintaining the general process conditions.

Japanese Patent Laid-Open No. 11-321839

  In view of the above-described background art, the present application discloses a square bottle made of thermoplastic resin having good self-standing stability.

This application is one of the means for solving the above-described problems.
A plastic square shape having a body portion and a bottom portion provided below the body portion, and having a cross-sectional shape orthogonal to the height direction of the body portion and a shape of the bottom surface of the bottom portion being substantially rectangular. In the blow molded bottle, the bottom surface has a substantially horizontal flat surface at an outer portion than the central portion, the flat surface portion has a convex portion protruding downward at a part thereof, When at least a part of the convex portion is in contact with the horizontal plane, the position of the convex portion on the bottom surface satisfies at least one of the following conditions (a) and (b): Discloses a square blow molded bottle.

Condition (a): Four intersections of a circle having a circle diameter ratio of 0.70 or more and 1.0 or less with respect to the long side length of the substantially quadrilateral centered on the center of the bottom surface and a diagonal line of the substantially quadrilateral. Including.
Condition (b): One circle having a circle diameter ratio of 0.70 to 1.0 with respect to the long side length of the substantially quadrilateral centered on the center of the bottom surface, and a straight line parallel to the four sides of the substantially quadrilateral Includes 8 points of intersection.

  In the square blow molded bottle of the present disclosure, it is preferable that the bottom surface has a recessed portion that is recessed upward at a central portion thereof, and the planar portion is provided at a peripheral portion outside the recessed portion.

  In the square blow molded bottle of the present disclosure, it is preferable that a thickness of the convex portion is 0.20 mm or more and 0.60 mm or less. * The lower limit was corrected from the experimental results.

  In the square blow molded bottle of the present disclosure, it is preferable that the protruding height of the convex portion is 0.30 mm or more and 0.60 mm or less.

In the square blow molded bottle of the present disclosure, it is preferable that a side length of the substantially square is 65 mm or more.

  In the square blow molded bottle of the present disclosure, it is preferable that a ratio of a long side length to a short side length of the substantially square is greater than 1.0 and 2.0 or less.

  In the square blow molded bottle of the present disclosure, the position of the convex portion on the bottom surface satisfies the condition (b), and the shape of the convex portion is in the vicinity of each corner of the substantially square shape among the eight intersection points. It is preferable that it is a linear shape or a planar shape including two points on the short side and the long side that are located on the side.

  In the square blow-molded bottle of the present disclosure, it is preferable that, in the condition (b), the lines parallel to the four sides of the substantially square are respectively equidistant from the four sides.

  The square blow molded bottle of the present disclosure can be filled with a liquid.

  The square bottle of the present disclosure has high self-supporting stability, can stand upright without being tilted or wobbled, and has a greatly reduced failure rate when filling and injecting liquid into an empty bottle, thereby producing liquid-filled products efficiently. Contribute to Moreover, even if the horizontal cross-sectional shape of a trunk | drum is a large square or a substantially rectangular shape, it is highly self-supporting and can design various bottles of beverage / liquid products. Furthermore, since it is possible to obtain good self-supporting stability without adding a heat setting process at the time of mold forming or strengthening cooling conditions, it can be applied to low-cost products such as room temperature bottles.

FIG. 2 is a schematic view for explaining a side surface and a front surface of a square bottle 10. 3 is a schematic view for explaining the bottom surface of the square bottle 10. FIG. It is the schematic for demonstrating the position of the convex part in a bottom face. It is the schematic for demonstrating the position of the convex part in a bottom face. It is the schematic for demonstrating the position of the convex part in a bottom face. It is the schematic for demonstrating the position of the convex part in a bottom face.

1. Definition of Terms In the present application, the “bottom part” of a bottle is the entire part including the bottom surface, which has a curvature from the trunk and is connected to the bottom surface.
In the present application, the “bottom surface” of a bottle is a surface of the bottle viewed from below.
In the present application, the “substantially square” does not need to be a perfect square, and may be a rounded square.
In the present application, the “substantially horizontal plane portion” does not need to be completely horizontal. The plane part may have an angle of 0 to 15 degrees or less with respect to the horizontal plane, preferably 12 degrees or less, more preferably 10 degrees or less.
In the present application, the “square blow molded bottle” refers to a square bottle obtained by blow molding a thermoplastic. That is, a bottomed cylindrical parison (preform) is heated and blown and stretched in a mold. Whether the square bottle is obtained by blow molding or not is determined based on the surface state and thickness of the square bottle (the body is thinner than 1 mm, the corner is thicker, the inner wall of the bottle Can be easily determined by observing the smoothness peculiar to blow molding, etc.). That is, the “blow molding” in the “square blow molded bottle” simply indicates the structure and state of the square bottle, and does not fall under “when the bottle manufacturing method is described”. Even if it is defined as “square blow molded bottle” in the claims, it does not fall under a product-by-process claim.

2. Square bottle 10
As shown in FIGS. 1 and 2, the square bottle 10 has a body 1 and a bottom 2 provided below the body 1, and has a cross-sectional shape orthogonal to the height direction of the body 1. This is a plastic square blow-molded bottle in which the shape of the bottom surface of the bottom portion 2 is substantially square. In the square bottle 10, the bottom surface has a substantially horizontal flat surface portion 2b on the outer side of the central portion (in FIG. 1 and FIG. 2, the recess portion 2a is recessed upward). Moreover, the plane part 2b has the convex part 2c which protruded below in the one part. When the square bottle 10 is erected on the horizontal plane, at least a part of the convex portion 2c is in contact with the horizontal plane. In the square bottle 10, it is important that the position of the convex portion 2c on the bottom surface satisfies at least one of the conditions (a) and (b) described later.

  As shown in FIG. 1, in the square bottle 10, the mouth portion 4 is provided above the trunk portion 1 via the shoulder portion 3, but the shape and position of the shoulder portion 3 and the mouth portion 4 are provided. Is not particularly limited. In the square bottle 10, the shoulder part 3 and the mouth part 4 are not essential parts for solving the above-mentioned problems, but can be appropriately changed in design. Since the shoulder 3 and the mouth 4 are obvious to those skilled in the art, the description thereof is omitted in the present application.

2.1. Torso 1
In the square bottle 10, the body 1 is not particularly limited as long as the cross-sectional shape is a substantially square shape and can form the square bottle. A specific example of “substantially square” will be described later. About the shape of the trunk | drum 1 other than this, since it is an obvious matter for those skilled in the art, description is abbreviate | omitted here.

2.2. Bottom 2
The square bottle 10 is characterized by the shape of the bottom surface of the bottom 2. As shown in FIGS. 1 and 2, the bottom surface has a recessed portion 2a (a dashed line portion in FIG. 2) recessed upward in the central portion, and a substantially horizontal flat surface portion 2b on the peripheral portion of the recessed portion 2a. Have. In the square bottle 10, the peripheral edge of the flat portion 2 b is connected to the body portion 1 with a curvature. Moreover, the plane part 2b has the convex part 2c (dotted line part of FIG. 2) which protruded below in the one part.

2.2.1. Indentation 2a
Although a hollow part is not essential in a square bottle, it is preferable to have the hollow part 2a hollowed upward in the center part of the bottom face like the square bottle 10 from a viewpoint of preventing a rocker bottom more appropriately. The shape of the hollow portion 2a in plan view is preferably a substantially quadrangle similar to a circle, an ellipse, or a substantially quadrangle of the trunk, with the center at the bottom as the center point. In particular, from the standpoint of self-supporting stability, an elliptical shape having a short diameter / long diameter ratio equivalent to the ratio of the short side length / long side length of a substantially quadrangular shape is preferable, as shown by a one-dot broken line in FIG.
The vertical cross-sectional shape of the recess 2a may be a smooth slope or may have one or more steps having a curvature. The number of steps is preferably two from the viewpoint of formability and load bearing strength.

  As for the magnitude | size of the planar view area of the hollow part 2a which occupies for a bottom face, 10% or more and 50% or less are preferable. More preferably, the lower limit is 20% or more and the upper limit is 40% or less. The plane part 2b can have an effective area ratio according to the numerical range described above. Moreover, by having the hollow part 2a of the above-mentioned numerical range, a bottom center part is extended to some extent and it is easy to obtain bottle strength.

  The thickness of the center of the recess 2a is preferably 1.5 mm or more from the viewpoint of the bottom strength of the bottle, and preferably 3.0 mm or less from the viewpoint of being easy to cool during molding and suppressing molding defects.

  The ratio of the height of the depression at the center of the depression 2a, in other words, the vertical height from the bottle ground contact surface, is preferably 0.10 or more and 0.40 or less with respect to the short side length of the substantially square. More preferably, the lower limit is 0.20 or more and the upper limit is 0.30 or less. When the ratio is 0.10 or more, the portion is stretched from the bottom center to the substantially horizontal surface of the periphery, and shrinkage due to the above-mentioned retained heat can be suppressed by stretching and thinning, and the bottle strength is improved. When the ratio is 0.40 or less, the uniformity of the stretched state is improved between the portion close to the center and the portion close to the flat portion 2b in the recess 2a.

2.2.2. Flat part 2b
As shown in FIGS. 1 and 2, in the square bottle 10, the center portion of the bottom surface of the flat surface portion 2 b is connected to the recess portion 2 a with a curvature, and the peripheral side has a curvature toward the bottle body portion 1. Have and be connected. In the plan view, the bottom surface is connected from the center to the peripheral portion in the order of the recessed portion 2a, the flat portion 2b, and the convex portion 2c.

  Since the square bottle 10 has the flat surface portion 2b, the shapeability of the convex portion 2c and the mold fidelity are improved, and the self-standing stability is improved. Further, when the square bottle 10 is filled with a liquid or the like and erects, the load is not locally applied only to the convex portion 2c, so that the convex portion 2c is hardly crushed.

The size of the planar view area of the planar portion 2b occupying the bottom surface is preferably 20% or more and 90% or less with respect to the area of the substantially square. The lower limit is more preferably 40% or more, and still more preferably 60% or more. On the other hand, the upper limit is more preferably 80% or less.
When the flat surface portion 2b has an area of 50% or more on the bottom surface, the flat surface portion 2b is unlikely to be thick, cooling sufficiently proceeds, and rocker bottom deformation is unlikely to occur. If the area of the flat surface portion 2b is 90% or less, the convex portions 2c are easily formed by resin flow of thermoforming.

  The thickness of the flat portion 2b is preferably 0.25 mm or more from the viewpoint of strength, and preferably 2 mm or less from the viewpoint of suppressing sink deformation. The lower limit is more preferably 0.4 mm or more, and the upper limit is more preferably 3.0 mm or less.

2.2.3. Convex part 2c
In the square bottle 10, the flat surface portion 2b has a convex portion 2c protruding downward at a part thereof. When the square bottle 10 is erected on the horizontal plane, at least a part of the convex portion 2c is in contact with the horizontal plane.

In the square bottle 10, it is important that the position of the convex portion 2c on the bottom surface satisfies at least one of the following conditions (a) and (b).
Condition (a): It includes four intersections of one circle having a circle diameter ratio of 0.70 or more and 1.0 or less with respect to the long side length of the substantially quadrangle centered on the center of the bottom surface and a diagonal line of the substantially quadrangle.
Condition (b): 8 intersection points of one circle having a circle diameter ratio of 0.70 or more and 1.0 or less with respect to the long side length of the substantially quadrilateral centered at the center of the bottom surface and a straight line parallel to the four sides of the substantially quadrilateral. including.

The condition (a) will be described with reference to FIG. In FIG. 3, the shape (substantially square) of the bottom surface of the square bottle 10 is indicated by a thick solid line, the circle centered on the center of the bottom surface is indicated by a thin solid line, the diagonal line of the substantially square shape is indicated by a broken line, The intersection with the circle is indicated by a black circle. FIG. 3A shows the case where the circle diameter ratio is 1.0, and FIG. 3B shows the case where the circle diameter ratio is 0.70. As shown in FIG. 3, when the condition (a) is satisfied, the position of the convex portion 2c on the bottom surface includes the four points shown in FIG. By providing the convex part 2c at a position including such four intersections on the bottom surface, the bottle self-supporting stability is improved.
The circle diameter ratio to the long side length is more preferably a lower limit of 0.75 or more and an upper limit of 0.9 or less.

  In the case where the condition (a) is satisfied, the shape of the convex portion 2c is not particularly limited, and may be any of a dot shape, a linear shape, and an irregular surface shape. In the case of a dot shape, the diameter is preferably about 1 mm to 3 mm, and in the case of a line shape, the width is preferably about 1 mm to 3 mm. In particular, a linear shape along a diagonal line is preferable. This is because the self-supporting stability becomes better and the strength in the vicinity of the corner portion having a high degree of stretching can be improved.

  When the condition (a) is satisfied, the number of the convex portions 2c is not particularly limited, and four convex portions separated from each other are provided as shown in FIG. 2, and each of the four intersections described above is provided. One may be included, or one continuous convex portion (a convex portion provided so as to make one round of the vicinity of the outer edge of the bottom surface) may include all four intersections. From the viewpoint of further improving the self-supporting stability, as shown in FIG. 2, it is preferable to provide four convex portions separated from each other. Alternatively, it is preferable that the convex portion 2c is not provided in the vicinity of the center of the substantially rectangular four sides on the bottom surface, that is, it does not have the convex portion 2c on the vertical bisector passing through the midpoint of each side.

  Further, in the condition (a), there may be a plurality of the above-mentioned circles concentrically, and there may be multiples of 4 intersections with the above diagonal lines. In this case, as shown in FIG. 4, it is possible to include two or more intersections in one convex portion 2c by making the convex portion 2c linear or planar along a diagonal line. In this case as well, one continuous convex portion may include all the intersections that are multiples of 4, but from the viewpoint of further improving the self-supporting stability and the like, as shown in FIG. It is preferable to provide four convex portions separated from each other. Alternatively, it is preferable that the convex portion 2c is not provided in the vicinity of the center of the substantially rectangular four sides on the bottom surface, that is, it does not have the convex portion 2c on the vertical bisector passing through the midpoint of each side.

The condition (b) will be described with reference to FIG. In FIG. 5, the shape (substantially square) of the bottom surface of the square bottle 10 is indicated by a thick solid line, the circle centered on the center of the bottom surface is indicated by a thin solid line, and the straight lines (four lines) parallel to the four sides of the substantially square shape are broken lines. The intersection of a straight line parallel to the four sides and the circle is indicated by a black circle. As shown in FIG. 5, the straight lines (four lines) parallel to the four sides of the substantially square are located on the center side from the short side and the long side of the bottom surface. 5A and 5B show the case where the circle diameter ratio is 1.0, and FIGS. 5C and 5D show the case where the circle diameter ratio is 0.70. As shown in FIG. 5, when the condition (b) is satisfied, the position of the convex portion 2c on the bottom surface includes eight points shown in FIG. By providing the convex portion 2c at such a position including the eight intersections on the bottom surface, the bottle self-supporting stability is improved.
The circle diameter ratio to the long side length is more preferably a lower limit of 0.75 or more and an upper limit of 0.9 or less.

In the case where the condition (b) is satisfied, the shape of the convex portion 2c is not particularly limited, and may be any of a dot shape, a linear shape, and an irregular surface shape. In particular, as shown in FIG. 6, among the above eight intersections, a linear or planar shape including two points on the short side and the long side located near each corner of the substantially quadrangular shape. Is preferred. This is because the self-supporting stability becomes better and the strength in the vicinity of the corner portion having a high degree of stretching can be improved.
The size of the convex portion 2c is preferably about 1 mm to 3 mm in diameter in the case of a dot, and about 1 mm to 3 mm in width in the case of a line.

  In the case where the condition (b) is satisfied, the shape of the convex portion 2c includes two points on the short side and the long side located in the vicinity of each corner of the substantially quadrangular shape among the eight intersection points. In the case of a connected linear or planar shape (FIG. 6), the shape between the two points includes the intersection of the above condition (a) (that is, the convex portion 2c is provided along the circumference of the circle), or Including a position outside the circle is preferable in terms of self-supporting stability. That is, as shown in FIG. 6, it is preferable that the planar shape of the convex part 2c bulges outward.

  Even when the condition (b) is satisfied, the convex portion 2c on the bottom surface is not provided in the vicinity of the center of the four sides of the substantially quadrilateral, that is, the convex portion on the vertical bisector passing through the midpoint of each side. It is preferred not to have 2c.

  In the condition (b), it is preferable that the straight lines parallel to the four sides are equidistant from the four sides, respectively. This is because the self-supporting stability and the like are further improved.

  As described above, in the condition (b), the straight lines (four lines) parallel to the substantially quadrangular four sides are located on the center side from the short side and the long side of the bottom surface. Here, in the condition (b), each of the straight lines parallel to the four sides preferably has a distance from the four sides of 0.05 times to 0.30 times the short side length of the substantially square, and the lower limit is 0. 0.06 times or more and the upper limit is more preferably 0.25 times or less, and further preferably 0.20 times or less. This is because the self-supporting stability and the like are further improved.

  Also in the condition (b), as in the case of the condition (a), there may be a plurality of concentric circles, and there may be multiples of 8 intersections with straight lines parallel to the four sides. In this case, the number of straight lines parallel to the four sides may be increased or decreased according to the number of circles.

  The convex part 2c may be a discontinuous shape that allows the corner of the bottom surface or the boundary with the flat part 2b to be visually recognized, or a continuous shape that cannot be recognized. In particular, as shown in FIG. 2, the convex portion 2c protrudes as a step from the central plane portion 2b, and the peripheral side has a shape that connects with a curvature to the vertical surface of the bottle body (central step shape). preferable. This is because the strength is further increased.

The protrusion height of the convex part 2c from the flat part 2b is preferably 0.30 mm or more, more preferably 0.35 mm or more from the standpoint of self-standing stability, and the upper limit is from the viewpoint of bottle strength or formability. 0.60 mm or less is preferable, and 0.55 mm or less is more preferable. In addition, since the thickness is the same regardless of whether the bottle is small or large, the degree of deformation is also the same. Therefore, the protrusion height can be determined without depending on the size (side length) of the bottle.
Here, the “projection height” of the convex portion 2 c is the height from the flat portion 2 b on the central portion side, and the height of the step from the flat portion 2 b on the central side is the same in the case of the step shape on the central side. Means.
If the protruding height is 0.30 mm or more, the grounding function of the grounding portion can be more appropriately maintained even if slight sink deformation occurs. If the protrusion height is 0.60 mm or less, cooling within the mold is sufficiently advanced and sink deformation is further suppressed, and good formability is obtained.
In addition, the protrusion height of each convex part 2c containing the above-mentioned 4 intersections or 8 intersections, or those multiple intersections is substantially uniform.

  As for the thickness of the convex part 2c, 0.20 mm or more and 0.60 mm or less are preferable. The lower limit is more preferably 0.25 mm or more, and the upper limit is more preferably 0.50 mm or less. Sufficient strength can be obtained by setting the thickness of the convex portion 2c to 0.20 mm or more. Further, by setting the thickness of the convex portion 2c to 0.60 mm or less, cooling after blow stretching sufficiently proceeds, and sink deformation when blow-stretched and taken out from the mold is further suppressed.

  The vertical cross-sectional shape of the convex portion 2c is preferably an arc shape having a radius of curvature of 0.5 mm or more and 10 mm or less, more preferably 1.5 mm or more and an upper limit of 8 mm or less from the standpoint of self-supporting stability and formability. By making the arc shape with a radius of curvature of 0.5 mm or more, resin mold adhesion in blow molding becomes good and cooling can be performed efficiently, so that the occurrence of sink deformation can be suppressed. By making the arc shape with a radius of curvature of 10 mm or less, the required strength can be imparted to the convex portion 2c.

  In particular, when the convex part 2c is planar, a shape that protrudes as a step from the flat part 2b on the center side and the peripheral side has a curvature to the vertical surface of the bottle body part (center side step shape) is preferable, The curvature radius of the step is preferably 0.5 mm or more and 10 mm or less, the lower limit is 1.5 mm or more, and the upper limit is more preferably 8 mm or less. By making the arc shape with a radius of curvature of 0.5 mm or more, the formability is sufficient, and by making the arc shape with a radius of curvature of 3.5 mm or less, it is easy to obtain good load resistance and pressure resistance. If the convex portion 2c has sufficient load resistance and pressure resistance, even if the bottle is filled with liquid and the bottom surface is pushed downward by its weight, the convex portion 2c is hardly deformed. Moreover, the shape side of a convex part tends to become favorable because a peripheral side is connected to a trunk | drum with the level | step difference from a center plane part.

2.3. Other preferable matters 2.3.1. In the case where the cross-sectional shape of the body portion and the shape of the bottom surface are substantially quadrangular, as in the case of the substantially square side-long square bottle 10, sink deformation is more likely to occur as the side length of the substantially quadrilateral increases. For example, when the side length of the substantially square is 65 mm or more, further 75 mm or more, and further 85 mm or more, sink deformation is likely to occur. In the prior art, it is difficult to suppress the sink deformation, but according to the square bottle 10, the sink deformation can be appropriately suppressed. In other words, from the viewpoint of the effect of the square bottle 10 becoming more remarkable, the side length of the substantially square is preferably 65 mm or more, more preferably 75 mm or more, and further preferably 85 mm or more. Although the upper limit of side length is not specifically limited, Preferably it is 150 mm or less, More preferably, it is 120 mm or less.

The substantially rectangular shape may be a substantially square shape or a substantially rectangular shape, but a substantially rectangular shape is preferred. In this case, the ratio of the long side length to the short side length of the substantially rectangular shape is preferably 2.0 or less. In other words, the ratio of the long side length to the short side length of the substantially quadrilateral is preferably greater than 1.0 and 2.0 or less. The upper limit is preferably 1.5 or less, and more preferably 1.2 or less, for stable upright with respect to vibration and shaking. Square blow molded bottles obtained by stretching from a bottomed cylindrical parison have different degrees of stretching when the bottom surface has a different distance from the center point. The above-mentioned range is preferable because heat shrinkage is large and sink deformation and rocker bottom deformation occur. In particular, in the past, when the horizontal cross section is substantially rectangular (ratio of more than 1.0), it is highly difficult to eliminate or suppress sink deformation, and it is effective to use the square bottle 10 of the present disclosure.
For example, the length of each side of the substantially square is a short side of 60 mm to 70 mm, a long side of 70 mm to 80 mm for a 750 mL capacity bottle, and a short side of 80 mm to 100 mm for a 2 L capacity. The long side may be about 100 mm or more and 120 mm or less.

2.3.2. Bottle height The height from the lower end of the bottle (the ground contact portion of the convex portion 2c) to the upper end (the upper end of the mouth portion 4) can be appropriately determined according to the length of each side of the substantially square and the capacity of the bottle. Good. For example, the height is preferably 150 mm or more and 350 mm or less, the lower limit is more preferably 180 mm or more, more preferably 200 mm or more, and the upper limit is more preferably 300 mm or less, and even more preferably 250 mm or less, thereby further improving self-supporting stability. Can be increased.

2.3.3. Material The material of the square bottle 10 may be a thermoplastic. Specifically, polyolefin resin and polyester resin are preferable, and polyethylene terephthalate resin is particularly preferable from the viewpoint of strength, heat resistance, transparency, and gloss. In the square bottle 10, known additives can be used in addition to the thermoplastic.

3. Method for Producing Square Bottle 10 The method for producing the square bottle 10 is based on a blow molding method in which a bottomed cylindrical parison (preform) is heated and blow-drawn in a mold. What is necessary is just to design the shape of a metal mold | die so that the shape of the square bottle 10 after shaping | molding may become what was mentioned above. The parison shape, its manufacturing method, and blow stretching conditions are known manufacturing methods and conditions. The square bottle 10 is excellent in self-supporting stability without being heat-set (heat-fixed) at the time of manufacture and without particularly strengthening the cooling conditions (temperature and time). As specific cooling conditions, for example, conditions for closely contacting a mold having a surface temperature of 15 to 75 ° C. for 1 to 4 seconds can be exemplified.

4). Application The application of the square bottle 10 is not particularly limited, but it is preferable that the interior is filled with a liquid. As described above, the square bottle 10 is excellent in self-supporting stability even when the liquid is filled therein. Although the kind of liquid is not specifically limited, For example, edible oil, industrial oil, seasoning, juice, etc. are mentioned.

  Hereinafter, the effect by the square bottle of this indication is explained in detail based on an example. In the following examples, the following bottom face appearance evaluation and self-supporting stability evaluation were performed on square bottles manufactured under various conditions.

<Bottom appearance evaluation>
The appearance of the bottom surface of the molded square bottle was observed from the viewpoint of the presence or absence of sink deformation or rocker bottom deformation.

<Independent stability evaluation>
The molded square bottle was erected on a horizontal base, tilted by 12 degrees toward the short side of the substantially rectangular shape of the body horizontal section, and then the time taken to erect and stop when the bottle was released was measured. Measurement was performed 5 times for each of 3 test specimens, and the average value was used to evaluate the self-supporting stability.

<Example 1>
A bottomed cylindrical 95 mm long parison made of polyethylene terephthalate resin (general bottle grade, intrinsic viscosity 0.83 dl / g, melting point 240 ° C., crystallization temperature 172 ° C.) is used and loaded into a mold made of SUS 2 By a step blow molding method (cold parison method), after heating for 40 seconds at a set condition of 100 ° C., a mold with a chiller set temperature of 15 ° C. and 3.0 MPa for 1.7 seconds (that is, the bottle adhered to the mold) Blow molding was performed under a set condition of a cooling time of about 1.7 seconds, and then the blow molded bottle was taken out from the mold.

  The bottle design shape of the mold has a mouth, a shoulder, a body, and a bottom, the total height is 225 mm, the inside diameter of the mouth is 27.6 mm, the horizontal horizontal section has a short side length of 66.6 mm, and a long side length of 76.3 mm. The bottom surface has a hollow portion at the center, the peripheral portion is a substantially horizontal flat surface portion, and has a convex portion protruding downward at a part of the flat surface portion.

The convex portion on the bottom surface has an arc having a diameter of 61.0 mm centered on the center of the bottom surface (circle diameter ratio 0.80 with respect to the long side length) and a position of 8.5 mm from the short side and the long side to the central side (substantially rectangular). The short side located in the vicinity of each corner among the eight points of intersection of the short side and four long side parallel line meters with the distance from the four sides of the short side and the position of about 0.13 times the short side length) A total of four linear protrusions connecting two points on the side and the long side (see FIG. 6). The convex portion has a width of about 2 mm and a length of about 20 mm in a plan view, and a protrusion height of 0.50 mm in a side view.
The recess at the bottom has an elliptical shape with a minor axis of 40 mm and a major axis of 45 mm (plane area ratio to the bottom of 37%) and a height of 17 mm (ratio with respect to the short side length of 0.26).

  The thickness of the center part of the depression at the bottom of the molded bottle was 2.8 mm, and the thickness of the convex part was 0.35 mm.

  The bottom surface appearance evaluation was good with no ground deformation and rocker bottom deformation because the projections provided on the bottom surface were grounded. The self-supporting stability evaluation value was 1.7 seconds.

<Example 2>
The convex part of the bottom surface includes the four convex parts of Example 1, protrudes as a step from the flat part on the center part side, and is connected with a curvature from the peripheral part to the vertical surface of the bottle body part with the protruding height. In addition, a bottle was molded in the same manner as in Example 1 except that it was a planar convex part having a central step shape.
The thickness of the center part of the depression at the bottom of the molded bottle was 2.8 mm, and the thickness of the convex part was 0.35 mm.
The bottom surface appearance evaluation was good with no ground deformation and rocker bottom deformation because the projections provided on the bottom surface were grounded. The self-supporting stability evaluation value was 1.7 seconds.

<Comparative Example 1>
In Example 1, a bottle was molded in the same manner as in Example 1 except that the flat part on the bottom surface of the mold was not provided with a protruding part protruding downward.
The thickness of the center of the depression at the bottom of the molded bottle was 2.8 mm.
The evaluation of the bottom surface appearance was poor because the vicinity of each center of the long side and the short side of the substantially horizontal surface at the periphery of the bottom surface swelled and deformed greatly downward in the bottle. The self-supporting stability evaluation value was 2.9 seconds.

<Comparative Example 2>
In Example 1, the convex portion on the bottom surface has four intersection points (long side side) of an arc having a diameter of 60 mm centered on the center of the bottom surface and two parallel lines of the long side from the long side to the long side at a position of 5 mm. 4 points of intersection (4 points on the short side) and 4 points of intersection between the parallel line of the 70 mm diameter arc centered at the center of the bottom surface and the short side 5 mm from the short side to the center side The bottle was molded in the same manner as in Example 1 except that the total number of point-like convex portions was 8).
The thickness of the center part of the depression at the bottom of the molded bottle was 2.8 mm, the thickness of the four long side convex parts was 0.35 mm, and the thickness of the four short side convex parts was 0.30 mm.
As for the bottom face appearance evaluation, the four long-side convex portions were good in formability and grounding, but the short-side convex portion four points were poor in shaping property and floated from the horizontal base, resulting in poor grounding. Therefore, when trying to erect, wobble continued for a long time, and the self-supporting stability evaluation value was 3.0 seconds or more.

<Comparative Example 3>
In Example 1, a bottle was molded in the same manner as in Example 1 except that no depression was provided at the center of the bottom surface and no projection was provided on the flat part.
The thickness of the flat portion of the bottom surface of the molded bottle was 2.5 mm.
The evaluation of the bottom surface appearance was poor because the flat portion was greatly bulged downward and deformed (rocker bottom deformation). In addition, due to the swelling, the self-supporting stability evaluation could not be performed.

  The square bottle of the present disclosure has extremely good self-supporting stability, and is easily erected even when it is subjected to transportation shaking with an empty bottle before filling the contents. Therefore, when an empty bottle is transported on the production line and liquid is injected from the bottle mouth, the bottle does not fall down, tilt, or continue to shake, and the liquid does not spill. In addition, since the rocker bottom and sink marks are not easily deformed, the aesthetic appearance is kept good. Therefore, in the production of beverages and the like, it is very useful for improving production yield and hygiene.

DESCRIPTION OF SYMBOLS 1 trunk | drum 2 bottom part 2a hollow part 2b plane part 2c convex part 3 shoulder part 4 mouth part 10 square bottle

Claims (9)

A body portion and a bottom portion provided below the body portion, and the shape of the cross section perpendicular to the height direction of the body portion and the shape of the bottom surface of the bottom portion are substantially rectangular. A square blow molded bottle,
The bottom surface has a substantially horizontal flat portion on an outer portion than the central portion thereof,
The plane part has a convex part protruding downward in a part thereof,
When the bottle is erected on a horizontal plane, at least a part of the convex portion is grounded to the horizontal plane,
The position of the convex portion on the bottom surface satisfies at least one of the following conditions (a) and (b):
Square blow molded bottle.
Condition (a): Four intersections of a circle having a circle diameter ratio of 0.70 or more and 1.0 or less with respect to the long side length of the substantially quadrilateral centered on the center of the bottom surface and a diagonal line of the substantially quadrilateral. Including.
Condition (b): One circle having a circle diameter ratio of 0.70 to 1.0 with respect to the long side length of the substantially quadrilateral centered on the center of the bottom surface, and a straight line parallel to the four sides of the substantially quadrilateral Includes 8 points of intersection. The bottom surface has a recessed portion that is recessed upward in a central portion thereof, and has the flat surface portion in a peripheral portion outside the recessed portion.
The square blow molded bottle according to claim 1. The thickness at the convex portion is 0.20 mm or more and 0.60 mm or less,
The square blow molded bottle according to claim 1 or 2. The protrusion height of the convex part is 0.30 mm or more and 0.60 mm or less,
The square blow molding bottle according to any one of claims 1 to 3. The substantially rectangular side length is 65 mm or more,
The square bottle according to any one of claims 1 to 4. The ratio of the long side length to the short side length of the substantially square is greater than 1.0 and 2.0 or less.
The square bottle according to any one of claims 1 to 5. The short side and the long side where the position of the convex portion on the bottom surface satisfies the condition (b) and the shape of the convex portion is located in the vicinity of each corner of the substantially square among the eight intersection points. It is a linear or planar shape that includes two points.
The square bottle according to any one of claims 1 to 6. In the condition (b), the lines parallel to the four sides of the substantially quadrilateral are equidistant from the four sides, respectively.
The square bottle according to any one of claims 1 to 7. The inside is filled with liquid,
The square bottle according to any one of claims 1 to 8.