JPS6121333A - Bottom structure of oriented blow molding vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (A) Object of the Invention [Industrial Application Field] The present invention relates to Zora stick bottles and other plastic containers manufactured by stretch blow molding, and particularly to the structure of the bottom of the container. It is something.

Stretch blow molding is one of the molding techniques for manufacturing plastics and containers.
After heating the cylindrical parison at an appropriate stretching temperature, the cylindrical parison is guided into the mold.
With both ends of the parison closed, air is blown into the parison to expand it along the shape of the outer mold, forming it into a bottle shape, for example, and after cooling,
It is taken out from the mold.

[Prior Art] The structure of the bottom of the stretch-blow molded container described above is, for example, as shown in FIG. It has become. The leg portions 101 have the function of supporting the container by contacting the floor surface 10.5. The strip portion 103 is made of a single plane, connects with the pinch-off portion 106, and is connected to the parting line 10.
It is formed in the direction of 7. Compared to the legs 101 and the shelf 102, this strip portion 103 is normally located at the farthest position from the floor surface 105.
When 0 is placed upward, the strip portion 103 appears as if it were a single groove.

The shelf portion 102 has a planar shape at an intermediate height between the leg portions 101 and the band portions 103.

FIG. 4 shows another example of the conventional bottom structure of a stretch-blow-molded container. In the example shown in FIG. 4, leg portions 101'' are formed all around the outer edge of the bottom surface.

[Problems to be Solved by the Invention] In the bottom structures shown in FIGS. 3 and 4, even if the molds are designed to realize the respective shapes, during cooling after blowing, Shrinkage causes uneven deformation called "sink marks," which often makes it impossible to achieve the shape exactly as the mold. When this "sink j" occurs, the dimensions become smaller as shown by the chain line in Fig. 5, and the deformation is uneven, so all the legs 101 do not touch the floor surface 105 evenly, making it difficult for the container to sit. Becomes unstable.

For this reason, there is a desire to develop a technology that can reduce this "sink mark."

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a bottom structure for a stretch-blow-molded container that can easily and reliably prevent the occurrence of sink marks.

(B) Structure of the invention [Means for solving the problem] In response to this object, the bottom structure of the stretch blow-molded container of the present invention is formed in the direction of the parting line on the bottom surface, and has a pinch-off portion. In the plane portion connected to the plane and consisting of a single plane, the width of the plane portion near the pinch-off portion is larger than the width of the adjacent portion.

Hereinafter, details of the present invention will be explained with reference to the drawings showing one embodiment.

In FIG. 1, reference numeral 10 denotes the bottom surface of the stretch-blow-molded container, and the bottom surface 10 is provided with leg portions 1 at four corners, and also consists of a shelf portion 2 and a band-shaped portion 3.

The legs 1 protrude from the bottom surface 10, have a function of supporting the entire container by being placed on and in contact with the floor surface 105, and have a height hl.

The strip 3 has a single plane and is formed in the direction of the paring line 7. This band-shaped portion 3 has a height 11 that is cut the most from the floor surface 105 compared to the leg portion 1 and the shelf portion 2 described later.
It is in position 3.

A pinch-off portion 6 protrudes from the middle heat portion 11 of the belt-shaped portion and 3 along the parting line 7.

Shelf? 1.1 The height l+2 located between the leg part 1 and the strip part 3 and between the height h3 of the high fold (hl> h2
>h3) forms a planar shape in the Q lock.

1,,, (7,"("What is especially important is the shape of the strip 3. 3. In other words, the strip 3 is formed with its longitudinal direction in the direction of the paring line 7, The width is not uniform over the entire length, and the width d1 of the central portion 11 corresponding to the pinch-off portion 6 is larger than the width d2 of the adjacent portion 12.

The medium heat portion 111 of the strip portion 3 where the pinch portions 17 and 6 are located has a relatively thick wall due to the characteristics of stretch blow molding.

1 Effect] In the bottom structure of the stretch-blow-molded container constructed in this manner, the central portion 11 of the strip portion 3 protrudes widely, and the width of the shelf portion 2 is reduced by the amount of the protrusion. The center part 11 of the strip part 3, which corresponds to the length of the pinch 47 part 6, is thick due to the characteristics of stretch blow molding, but since that part is made wide d1, the excess plastic material is stretched, and the amount of stretching is The excess plastic material in the central part 11 flows into the shelf part 2 with a large surface area, so that there is no accumulation of excess plastic material in the central part 11 that causes sink marks, which results in a thinner wall and improved plasticity to prevent sink marks. It is possible to perform molding according to the mold without any occurrence of molding.

<Example> A parison of A-refin plastic was formed into a container having a bottom as shown in FIG. 2 by stretch blowing.

Δ-6~10II10 ll1+(2~6) mm a = 40' ~ 506 Results for 25° ~ 35°■ The conventional type with a constant band width of 6 to 1.2 mm has 1 dimension. (Difference between old - h3) should have been 9n+m, but now it is 7mm.

(2) In the case of the present invention, there was no change in the method 1-11, so no sink marks were caused).

(ΦIn addition, when a rib is attached to the shelf part (not indicated by the symbol 9), 1
"Dimensions are 9mm and 7.5-8.0m
It became m.

(C) Effects of the Invention As is clear from the above explanation, according to the present invention, it is possible to easily and reliably prevent the occurrence of sink marks.
The bottom structure of the container can be obtained.

[Brief explanation of the drawing]

FIG. 1A is a plan view showing the bottom of the container of the present invention, FIG. 1B
2 is a plan view showing the dimensional relationship of the bottom of the container according to the present invention, and FIG.
Fig. 3 A is a plan view showing an example of the conventional container bottom, and Fig. 3 B is a B-B section view in Fig. 3.
- A side view of part B; FIG. 4A is a plan view showing another example of the conventional container bottom; FIG. 4B is a side view of part B-'B in FIG. 4A; and FIG. FIG. 2 is a cross-sectional explanatory view showing the state of sink marks at the bottom of a conventional container. 1... Leg part 2... Shelf part 3... Band-shaped part
6... Pinch-off part 7... Parting line 10... Bottom surface 11... Center part 100.
... Bottom part 101 ... Leg part 102 ... Shelf part 1
03... Band-shaped part 105... Floor surface 106...
・Pinch-off portion 107... Parting line Patent applicant Osamu Kawai, Patent attorney representing Toyo Seikan Co., Ltd. (A) (B) (A)' Figure 2 (B) Figure 3 (A) ( B)

Claims (1)

[Claims] In a flat part of the bottom surface formed in the parting line direction, connected to the pinch-off part, and consisting of a single plane, the width of the flat part near the pinch-off part is larger than the width of the adjacent part. A bottom structure of a stretch blow-molded container characterized by: