JPS61123513A - Manufacture of stretched and blow molded container - Google Patents

Abstract

PURPOSE:To provide the title container free from wrinles at the constricted section, by blow molding a bottomed parison in such a way that the part of the parison that is part of the barrel section has a diameter equal to or smaller than the mouth section of the end product. CONSTITUTION:The configuration of inner surfaces 6 of molds that will abut against a parison is set such that the part of the bottomed parison 5 to be molded that extends from the mouth section 11 to approximately the middle of the barrel section has approximately the same diameter, that is the relation ship: the width (w) of the constricted section of the end product > the diameter (D1) of the parison is satisfied. The parison 5 is inserted in molds 7, 7, a gas is blown to stretch outwardly the part corresponding to the constricted section in the direction normal to the axis and also to stretch the whole body.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing a stretch-blow-molded container, and in particular, it relates to a method for manufacturing a stretch-blow-molded container. The present invention relates to a method for stretch-blow molding a container having a container without causing wrinkles.

[Prior art]

In recent years, many kitchen detergents have been sold in molded plastic bottles, and they have reached the point where they are always kept in most homes and workplaces. In order to make it easier to grip and handle the bottle without slipping or sipping, it is common for the upper part of the bottle body (slightly below the mouth) to be narrower than the center of the body, and to have an uneven pattern. (See Figure 5).

On the other hand, when manufacturing such plastic bottles,
Conventionally, the process was as shown in Figure 3. First, the process was carried out by blow molding. Bottomed balin 7 (
Immediately after molding 13), the bottomed parison 03) is transferred into a blow molding mold (14) and air is blown thereinto to obtain a molded product.

Another known method is to reheat the bottomed valine y (13), stretch it with a blow pin, and then blow mold it.

[Problem that the invention seeks to solve]

However, in the conventional method for producing glass bottles, typified by the method described above, in the case of the former blow molding method, the bottomed burin/(13) formed by blow molding is replaced by the mouth part (11) as shown in Figure 4. The ridge at the portion (15) slightly below the mouth portion (14) is made larger than the diameter d1 of the mouth portion (14). Therefore, when blow molding is performed using such a bottomed balline 7 (13), there is a problem that the portion (15) adheres to the mold and hardens, causing wrinkles in the final product. There is.

In addition, the latter stretch-blow molding method has the advantage that the bottomed valine is stretched in the axial direction, resulting in a molded product with excellent transparency, rigidity, and impact resistance. At present, stretching is performed only in the axial direction, and not in the direction perpendicular to the axis. Therefore, in stretch blow molding, a constriction (10) is formed slightly below the mouth of the container body, as shown in Figure 5.
When forming a fan, as shown in Fig. 4, the diameter d of the point (15) is set larger than the width (b) of the constriction part (l) of the final product at the bottomed burin stage, and then The width (B) is formed using a mold.Therefore, as with the former method, there is a problem in that wrinkles occur at the constriction (10).

[Means for solving problems]

The manufacturing method of the present invention was devised to solve the above-mentioned problems of conventional plastic bottles, and the manufacturing method of the present invention is such that a part of the body of the container body of the bottle as a final product is made thinner than the diameter of the mouth. Or, in order to make the diameter almost the same, at the bottomed burin stage, the part that becomes part of the body (hereinafter referred to as the constriction) is thinner than the diameter of the mouth of the final product or has approximately the same diameter. The corresponding part (hereinafter referred to as the small diameter part) is blow-molded so that it is thinner than the final product, and then the constricted part is also extended in an outward direction approximately perpendicular to the axis to form the entire body into the desired shape. It is characterized by being stretch blow molded to size.

[Effect]

In the manufacturing process of the present invention, when the blow-molded bottomed parison is introduced into a mold for stretch blow molding and fixed, there is a gap between the mold and the small diameter part of the bottomed parison, so the stretching The blowing stretches the small diameter section until it reaches the predetermined dimensions of the mold, yielding the desired final product of the plastic bottle.

〔Example〕

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

Fig. 1 is an explanatory diagram showing the manufacturing process of the present invention. First,
In the process, molten resin is extruded from the die head (1) to form a parison. Next is process ■.

In ■, the mold (3) is removed from both sides of the balin/(2).
(3) is brought close to and in contact with the ballin/(2), and the upper end of the parison (2) is cut with a cutter. Furthermore, after that, the blow head (4) is inserted through the opening of the burin/(2) formed by the cutting, and a gas such as air is blown into the inner surface (6), which comes into contact with the shape as shown in Fig. 2. In other words, in Fig. 2, the diameter is approximately the same from the mouth (11) of the bottomed bottle/(5) to the approximately center of the body. The diameter of the corresponding part is the diameter of the constriction.
) is set so that it is smaller than .

Next, in step (2), the molded Jinsha Hekiyuzoku Hariso/(5) is inserted into a mold (7) (7) having an inner surface shape that fits the shape □ of the plastic bolt as the final product. In step V, the mold (7) (7) is closed and gas such as air is blown from the blow head (8), and at the same time, the part corresponding to the constriction is blown outward at right angles to the axis using a desired jig such as a screwdriver. While stretching, the entire bottle is stretched, and in step (2), the blow head (8) is retracted and the mold (7) (7) is opened to discharge the molded plastic bottle (9).

The plastic bottle (9) molded in this way is shown in Figure 5, with Figure 5A showing the front view and Figure 5 the mouth showing the side view. Part (11)
The diameter is slightly smaller than, or approximately equal to, the diameter of. In addition,
In the figure, (12) is an uneven strip that also serves as a pattern to prevent slipping during handling.

〔Effect of the invention〕

Since the present invention is constructed as described above, it is possible to achieve an excellent appearance without wrinkles at the constriction by simply setting the diameter of the bottomed parison to a predetermined value without fundamentally changing the conventional process. This has the effect of making it possible to efficiently manufacture plastic bottles.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the process of the present invention, Fig. 2 is a front view of the bottomed parison molded according to the present invention, Fig. 3 is an explanatory diagram showing the process of the conventional manufacturing method, and Fig. 4 is an explanatory diagram showing the process of the conventional manufacturing method. Front view of the bottomed Balinon molded by the manufacturing method, Figure 5 (A) (
B) is a front view and a side view showing an example of a plastic bottle manufactured according to the present invention. (1)...Gui head (2)...Parison (
3) (7)...Mold (4) (8)...
・Blow head (5)...bottomed parison (6)・
...Inner surface (9)...Plastic bottle (10)...Neck part (1υ Middle mouth part (12)
...Irregular rows by Kazuo Suzuki Figure 1 MY W Figure 2 Figure 4 Figure 3 Craftsmanship ■ ■ ■Y'' W

Claims (1)

[Claims] A method for manufacturing a container having a constriction part having a diameter equal to or smaller than the mouth part in a part of the body, the diameter of the part corresponding to the constriction part of the bottomed parison being formed to be thinner than the constriction part. A method for producing a stretch-blow-molded container, characterized in that the container is then stretch-blow-molded while also stretching the portion corresponding to the constriction in an outward direction perpendicular to the axis.