JP2001180637A - Synthetic resin square heat-resistant bottle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of irregular deformation and to ensure a satisfactory stability on setting for a bottom part of a heat-resistant square bottle body made of synthetic resin by biaxially stretched blow molding with a heat resistance given by means of heat setting. SOLUTION: A grounding part 8 at the bottom part 7 of the heat-resistant square bottle body made of synthetic resin by biaxially stretched blow molding is constructed of flat wall part opposite grounding parts 9 each in a narrow planate grounding structure faceing each of flat wall parts 5 of a trunk part 4 and corner wall part opposite grounding parts 10 each in a linear grounding structure facing each of corner wall parts 6 of the trunk part 4, and thereby the amount of deformation by heat shrinkage at the flat wall part opposite grounding parts 9 and the amount of deformation by sink shrinkage at the time of releasing mold are made approximately the same with each other, ensuring a satisfactory stability for setting the bottle body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of the bottom of a synthetic resin rectangular bottle which is biaxially stretch blow-molded and provided with heat resistance by heat setting.

[0002]

2. Description of the Related Art As shown in FIG. 4, a biaxially stretched blow-molded bottle made of synthetic resin has, at its center, a recessed central portion 11 which is depressed into a bottle in a substantially hemispherical shell shape. 11
Between the tapered wall portion 13 formed around the outer periphery and the rising cylindrical wall portion 14 forming a connection portion with the trunk portion, a grounding portion 8 ′ of a surface grounding structure is formed in a ring shape. Is common.

The structure of the grounding portion 8 'is the same regardless of whether the bottle is rectangular or heat-resistant by heat setting, and is formed into a ring shape with an equal width. I was

[0004]

However, in the above-mentioned prior art, if the bottle has a rectangular structure, the grounding portion 8 'opposing the flat wall portion 5 of the bottle body, and the bottle The flat wall portion 5 is located between the grounding portion 8 ′ facing the square wall portion 6 of FIG.
There is a difference that the amount of extension is greater at the grounding portion 8 'facing the square wall portion 6 than at the grounding portion 8' facing the surface.
According to the difference in wall thickness resulting from this difference, there is a problem that good formability and the degree of thermal deformation are clearly different, and the resulting deformation is an irregular deformation, which deteriorates "sitting". .

When heat setting is performed to impart heat resistance, the formability of the grounding portion 8 'facing the flat wall portion 5 is improved, and the formability of the entire bottom portion is improved.
Since the bottle, which is a molded product, is released at a relatively high temperature, the ground portion facing the flat wall portion 5, which is thicker than the ground portion 8 ′ facing the square wall portion 6. There has been a problem that the amount of heat shrinkage of the portion 8 'becomes large, and a large irregular deformation occurs at the bottom.

Further, in the case of a heat-resistant square bottle which is reduced in weight, the thinner the thickness is, the better the moldability is, and in combination with the improvement in the moldability by heat setting, an extremely high shapeability can be obtained. However, since the thickness of the portion of the ground contact portion 8 'facing the square wall portion 6 is greatly reduced, the amount of heat shrinkage after release from the mold is larger than in the above case, and the "seat" of the bottom portion is poor. As a result, there is a problem that the defective product generation rate increases.

Accordingly, the present invention has been made to solve the above-mentioned problems in the prior art, and is intended to provide a synthetic resin square bottle which is biaxially stretch blow-molded and has been given heat resistance by heat setting. A technical object is to prevent the occurrence of irregular deformation of the bottom portion, and an object of the present invention is to provide a biaxially stretch blow-molded heat-resistant square bottle made of synthetic resin, which stably exhibits a good "sitting" function.

[0008]

Means for Solving the Problems The present invention, which solves the above technical problem, comprises a synthetic resin having a square cylindrical body, blow-molded biaxially stretched, and provided with heat resistance by heat setting. That it is related to the structure of the bottom of the rectangular bottle made of stainless steel, which rises from the lower end of the body and is connected to the bottom of the cylindrical wall,
Forming a grounding portion between the tapered wall portion formed around the center of the central portion of the bottom and the rising cylindrical wall portion of the bottom portion, the grounding portion is opposed to the flat wall portion of the trunk portion. And a flat wall facing grounding portion having a narrow surface grounding structure, and a square wall facing grounding portion having a line grounding structure facing the corner wall of the body. ,It is in.

[0009] Of the grounding portions at the bottom, the flat wall-facing grounding portion has a narrow surface grounding structure, and the portion where the flat wall-facing grounding portion is located is line grounded. As compared with the case where the structure is adopted, the stretching amount is increased, and the thickness is reduced accordingly, so that relatively good moldability is exhibited.

On the other hand, of the grounding portions at the bottom, the grounding portion facing the square wall portion has a line grounding structure, so it is in a locally extended state, and is formed to be extremely thin with good formability. Is done.

[0011] Further, since the bottle is subjected to a heat-setting treatment at the time of the biaxial stretch blow molding, the formability is generally improved, so that the good formability of the bottom portion is as follows. It will be high enough.

As described above, the bottom portion is formed with a sufficiently high formability, but the amount of extension of the flat wall facing ground portion is smaller than that of the square wall facing ground portion. For this reason, the amount of heat shrinkage deformation after the mold release is larger in the flat wall portion-grounded portion than in the square wall portion-grounded portion.

However, since the corner wall facing grounding portion is in a locally extended state and is formed to be extremely thin, if the mold is released at a relatively high temperature in a heat-set state, the molding of the mold is performed. At the moment when the mold is separated from the mold surface, it contracts and deforms in a “pulling” shape, so that the entire grounding portion at the bottom contracts and deforms equally between the flat wall facing grounding portion and the square wall facing grounding portion.

This tendency increases with the degree of thinning of the bottom, so that the lighter the bottle, the more remarkable the action.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIG.
This will be described with reference to FIG. The rectangular bottle 1 according to the present invention is a heat-resistant bottle made of synthetic resin and biaxially stretched and blow-molded, and a mouthpiece 2 is continuously provided at an upper end via a shoulder 3 having a tapered square tubular shape. Body 4 with bottom 7 connected to lower end
Is formed into a square-shaped square tube structure with a flat wall portion 5 and a ridge line portion as a square wall portion 6.

As in the prior art, a panel wall portion for decompression absorption is recessed in each flat wall portion 5 of the quadrangular cylindrical body 4, and a central portion of the body 4 is A central circumferential groove for increasing buckling strength is provided.

The bottom 7 is depressed in the center of the bottle into the inside of the bottle, and its peripheral wall has thick reinforcing ribs 12 extending in the radial direction.
Are provided at regular intervals along the circumferential direction, and a tapered wall portion 13 gently inclined downward from the peripheral edge of the recessed central portion 11 is continuously provided.
The grounding portion 8 is formed between the peripheral edge of the cylindrical member 3 and the lower edge of the rising cylindrical wall portion 14 connected to the lower edge of the body portion 4.

The grounding portion 8 is opposed to the flat wall portion 5 of the body portion 4 (located immediately below the flat wall portion 5) and to the corner wall portion 6 of the body portion 4. Square wall facing grounding section 1
The flat-wall-facing grounding portion 9 is a surface grounding structure having a narrow grounding surface (see the solid line portion in FIG. 3). Grounding structure (Fig. 3
(See the two-dot chain line illustration).

The flat wall opposed grounding portion 9 has the width at both ends reduced as it approaches the square wall opposed grounded portion 10 (see FIG. 2). It has a rectangular shape substantially the same as the rectangular tube shape.

[0020]

Since the present invention has the above-described structure, the following effects can be obtained. A flat wall facing ground portion facing the flat wall portion of the body, and a square wall portion facing the square wall portion of the body in the grounding portion at the bottom of the synthetic resin heat-resistant square bottle formed by biaxial stretching blow molding. There is almost no difference in the amount of heat shrinkage deformation between the opposing grounding portion and the grounding portion at the bottom portion is irregularly deformed, and the occurrence of the inconvenience of deteriorating the "sitting" function is extremely effectively prevented. be able to.

In addition, even if the heat set treatment is performed and the weight is significantly reduced, even if the difference in the degree of heat shrinkage deformation between the flat wall facing ground portion and the square wall facing ground portion of the grounding portion becomes large, Due to the increase of “shrinkage” -like shrinkage deformation at the time of mold release accompanying the promotion of thinning, the shrinkage deformation in each part of the grounding part is equal, and thus the shrinkage deformation of the grounding part does not deteriorate the appearance of the grounding part, Will be done.

[Brief description of the drawings]

FIG. 1 is an overall front view showing an embodiment of the present invention.

FIG. 2 is an enlarged bottom view of the embodiment shown in FIG.

FIG. 3 is an enlarged longitudinal sectional explanatory view of a main part of the embodiment shown in FIG. 2;

FIG. 4 is an enlarged bottom view showing a conventional example.

[Explanation of symbols]

 1; square bottle 2; mouthpiece 3; shoulder 4; trunk 5; flat wall 6; square wall 7; bottom 8; grounding 8 '; Square wall facing grounding portion 11; Depressed center portion 12; Reinforcement rib 13; Tapered wall portion 14;

Continued on the front page (72) Inventor Daisuke Uesugi 310 Minatodai, Matsudo-shi, Chiba Prefecture Inside Matsudo Plant, Yoshino Kogyo Co., Ltd. Person Hiroaki Sugiura 3-2-6 Oshima, Koto-ku, Tokyo F-term in Yoshino Kogyosho Co., Ltd. (reference) 3E033 AA01 BA13 CA02 CA05 CA07 DA03 DA08 DB01 DD05 EA03 EA04 EA05 EA12 FA03

Claims (1)

[Claims] 1. A synthetic resin square bottle (1) having a body portion (4) in the shape of a rectangular cylinder, biaxially stretch blow-molded, and heat-resistant provided by heat setting. Department (4)
The bottom (7) of the bottom (7) connected to the lower end of the
Tapered wall formed around the central depression (11)
The grounding portion (8) formed between the (13) and the rising cylindrical wall portion (14) is provided with a narrow surface grounding structure facing the flat wall portion (5) of the trunk portion (4). Made of synthetic resin comprising a flat wall opposed grounding portion (9) having a rectangular wall opposed grounding portion (10) having a line grounding structure facing the square wall portion (6) of the body portion (4). Square heat-resistant bottle.