JP2581837Y2 - Polyester resin bottle bottom structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxial stretch blow-molded bottle made of a polyester resin having a specific bottom structure, and more particularly to a biaxial polyester resin biaxial tube having improved bottom load resistance and heat resistance. The present invention relates to a bottom structure of a stretch blow-molded bottle.

[0002]

2. Description of the Related Art In recent years, containers made of polyester resin such as polyethylene terephthalate have been used instead of glass containers which have been widely used as containers for soft drinks and natural juice drinks. The polyester resin container has various advantages such as impact resistance, safety in the event of breakage, and lightness. However, on the other hand, it is easily deformed when a liquid load is applied, and irreversible deformation may occur depending on a long-term load. Further, they are remarkably inferior in heat resistance to glass and easily deformed by heat treatment for sterilization or the like. Particularly in a biaxially stretched blow-molded bottle, since the resin at the bottom of the bottle tends to be insufficiently stretched, the load resistance and heat resistance of the portion are inferior, and the bottle is deformed mainly into the bottle bottom by liquid load or heating or both. Occurs. For this reason, for example, in the case of a bottle for natural juice, which needs to be filled with the contents subjected to high-temperature treatment or subjected to heat treatment for sterilization after filling, a problem of deformation of the bottle bottom occurs. In order to solve these problems, a method of strengthening the bottom of a blow-molded bottle has conventionally been devised.

For example, various studies have been made on the structure of the bottom of a bottle in order to increase the degree of stretching of the bottom of the bottle. JP 6
No. 2-146137 discloses a bottom structure having undulations along an upper surface of a plurality of quadrangular pyramids arranged so as to protrude toward the inside of the bottle continuously and concentrically in a concave portion of the bottom of the bottle. I have. Further, Japanese Utility Model Laid-Open No. 61-183803 discloses a bottom structure having an inclined wall which is rapidly depressed toward the inside of the bottle at the bottom of the bottle, and a plurality of reinforcing ribs radially extending from the center of the bottom of the inclined wall. ing.

[0004]

In the former of the above prior arts, it is extremely difficult to accurately form undulating corners along a plurality of quadrangular pyramids arranged so as to project toward the inside of the bottle. Therefore, the intended effect could not be sufficiently achieved. In the latter, the heat resistance was insufficient because the degree of stretching at the bottom was insufficient. Furthermore, in the prior art, the degree of stretching at the center of the bottom of the bottle tends to be extremely insufficient.

An object of the present invention is to solve the problems of the prior art and to provide a bottom structure of a biaxially stretched blow-molded bottle made of polyester resin having improved load resistance and heat resistance.

[0006]

Means for Solving the Problems That is, the present invention relates to 2
A bottom structure of an axially stretch blow molded polyester resin bottle, an annular bottom heel portion connected to a lower end portion of a side wall of the bottle, a recess surrounded by the bottom heel portion, and A plurality of first bulges formed so as to be annularly and radially arranged at regular intervals, the bulges having truncated pyramids whose truncated surfaces rise from the surface of the recess. And a second bulge smaller than the first bulge formed radially between each of the plurality of first bulges. Provides bottom structure.

Since the present invention has such a configuration, unlike the prior art disclosed in Japanese Patent Application Laid-Open No. 62-146137, it is possible to easily and undulate the bottom of the bottle using a conventional blow molding technique. This is performed reliably, whereby the degree of stretching of the resin at the bottom of the bottle is drastically increased, so that a bottle excellent in load resistance and heat resistance at the bottom can be manufactured.

The present invention further provides a truncated conical shape in which the inside diameter of the bottom is smaller than the inside diameter of the opening in the center of the recess and surrounded by the plurality of first bulges. There is also provided a bottom structure characterized by further forming a central recess having the same.

[0009] The presence of the central recess greatly improves the degree of stretching of the resin at the center of the bottle bottom, which could not be sufficiently stretched by the prior art. It is possible to manufacture a bottle with even higher load resistance and heat resistance as the entire bottom.

In the present invention, as the truncated pyramid, a truncated triangular pyramid to a truncated pentagonal pyramid or a truncated pyramid having a greater number of angles can be used as appropriate. However, truncated triangular pyramids and truncated quadrangular pyramids are generally preferred from the viewpoint of ease and reliability of molding.

The number of the first bulging portions is not particularly limited, and can be appropriately determined according to the size and thickness of the bottle and other practical conditions. For example, in the case of a bottle having a capacity of 1 L, the number can be usually 4 to 10 bottles. There is no particular limitation on the size of the bulging portion, and it can be appropriately determined according to the working conditions.

The second bulge may have a shape similar to or reverse to the shape of the first bulge, or may have an arbitrary shape such as a spindle shape, a bullet shape, a tear shape, or a semi-cylindrical shape. You can also. The second bulging portion further enhances the degree of stretching by the first bulging portion and also functions as a reinforcing rib.

[0013]

As described above, the present invention utilizes a bulging portion having a truncated pyramid shape in order to improve the degree of stretching at the bottom, so that the inside of the bottle as described in JP-A-62-146137 is used. The molding can be performed easily and reliably as compared with the related art using undulations along a plurality of quadrangular pyramids arranged so as to protrude toward. For this reason, according to the present invention, the molding process of the bottle bottom is stabilized, and a bottle of uniform quality can be easily manufactured. In addition, 61-183803
In comparison with a bottom structure having an inclined wall which is rapidly depressed toward the inside of the bottle at the bottom of the bottle and a number of reinforcing ribs extending radially from the center of the bottom as described in the above item, the bottom of the bottle is The degree of stretching is dramatically increased. Further, the stretching degree at the center of the bottom, which has been extremely insufficient in the past, can be further enhanced to reinforce this portion. Therefore, according to the present invention, it is possible to provide a biaxially stretched blow-molded bottle which is superior in the load resistance and heat resistance of the bottom portion as compared with the prior art.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows a bottom of a bottle according to a first embodiment of the present invention, with the bottom of the bottle facing upward. In FIG. 1, FIG. 2 is a partially enlarged view. In the figure, 1 is a part near the bottom of the bottle side wall. Reference numeral 2 denotes a bottom heel, which surrounds the recess 3, in which six first bulging portions 4 are formed. The first bulging portion 4 has a truncated quadrangular pyramid shape, and 5 is a truncated surface thereof, which rises from the surface of the concave portion 3. 6 and 7 are the sides of the truncated pyramid. A second bulge 8 is formed between each of the first bulges 4, and in the present embodiment, it has a spindle shape. Reference numeral 9 denotes a truncated conical central recess.

FIG. 2 is a cross-sectional view taken along a plane including the center axis of the bottle and passing through the center of the spindle-shaped second bulging portion 5, and the meanings of the reference numerals are the same as those in FIG. As is clear from FIGS. 1 and 2, the central recess 9 has an inverted truncated cone shape in which the inner diameter of the bottom is smaller than the diameter of the opening.

FIG. 3 is a sectional view taken along a plane including the central axis of the bottle and passing through the center of the first bulge;
The meanings of the symbols are the same as in FIG.

FIG. 4 is a perspective view in which a part of the bottom structure including one first bulge is cut out and enlarged. In the figure, 1 is a bottle side wall, 2 is a bottom heel, 3 is a recess, 4 is a first bulge, 8 is a second bulge, 9 is a central recess, and 5 is a truncated square. The truncated faces of the pyramid, 6 and 7, are its sides.

In this embodiment, since the structure is as described above, the degree of stretching of the bottom is high, the load resistance and the heat resistance are excellent as described above, and the molding can be performed easily and reliably.

Embodiment 2 FIG. 5 is an enlarged perspective view of a part of a bottom structure including one first bulging portion according to a second embodiment of the present invention. 11 is a bottle side wall, 12 is a bottom heel portion, 13 is a concave portion, and 14 is a first bulging portion. The first bulge 14 is a truncated triangular pyramid, 15 is its truncated surface, and 16 and 17 are its side surfaces. Reference numeral 18 denotes a second bulge, and 19 denotes a central recess. The shape of the present embodiment is the same as that of the first embodiment except for the shape of the first bulging portion 14.

Embodiment 3 FIG. 6 is a perspective view showing a part of a bottom structure including a first bulging portion according to a third embodiment of the present invention, which is cut away and enlarged. 21 is a bottle side wall, 22 is a bottom heel, 23 is a recess, and 24 is a first bulge. The first bulge 24 is a truncated pentagonal pyramid, 25 is its truncated surface, and 26 and 27 are its side surfaces. 28 is a second bulge, and 29 is a central recess. The shape of this embodiment is the same as that of the first embodiment except for the shape of the first bulging portion 24.

[0021]

[Effect of the Invention] Since the present invention has the above-mentioned action, it can be filled with a high-temperature content liquid such as a beverage containing natural juice, or can be subjected to a heat treatment such as a high-temperature shower or the like for sterilization after filling. Provided is a bottom structure of a reinforced biaxially stretch blow-molded bottle, which is optimally widely used as a bottom structure of a bottle requiring load resistance and heat resistance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a bottom structure according to a first embodiment.

FIG. 2 is a cross-sectional view of the bottom structure of the first embodiment, taken along a plane including the center axis of the bottle and passing through the center of a second bulging portion.

FIG. 3 is a cross-sectional view of the bottom structure of the first embodiment, taken along a plane including the center axis of the bottle and passing through the center of the first bulging portion.

FIG. 4 is an enlarged perspective view of a part of the bottom structure including one first bulging portion of the first embodiment.

FIG. 5 is an enlarged perspective view of a part of a bottom structure including one first bulging portion of the second embodiment.

FIG. 6 is an enlarged perspective view of a part of a bottom structure including one first bulging portion of a third embodiment.

[Explanation of symbols]

1, 11, 21 ... bottle side wall, 2, 12, 22 ... bottom heel part, 3, 13, 23 ... concave part, 4, 14, 24 ... first bulging part, 5 , 15, 25... Truncated surfaces of truncated pyramids 6, 7, 16, 17, 26, 27,. . . Side face of truncated pyramid 8, 18, 28 ... second bulge, 9, 19, 29 ... central recess,

Claims (1)

(57) [Scope of request for utility model registration] 1. A bottom structure of a biaxially stretch blow-molded polyester resin bottle, comprising: an annular bottom heel portion connected to a lower end portion of a side wall of the bottle; and a concave portion surrounded by the bottom heel portion. A plurality of first bulges formed in the recess so as to be arranged in a ring and radially, wherein a mounting surface rises from a surface of the recess, and a mounting triangular pyramid or mounting square.
A first bulging portion having a shape of a pyramid or a mounted pentagonal pyramid , and the first bulging portion formed so as to be radially arranged between each of the plurality of first bulging portions. A second bulge smaller than the bulge, and a second bulge before being surrounded by the plurality of first bulges.
At the center of the recess, the shape of a truncated cone that tapers into the bottle
A bottom structure comprising a central recess having: