JP2001179815A - Mold for blow molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for blow molding which can obtain a bottle having high stress cracking resistance and a good appearance even when a bottle of a special shape such as a blow-molded bottle with a handle is molded. SOLUTION: In the mold for blow molding formed by opening/closing a split mold, parison holding slide blocks, which are facing each other, of a pair are set movably at positions below and close to the pinch-off of the bottom part of the cavity of the split mold 110, respectively. During mold opening, slide blocks 120 are protruded by a prescribed position. During mold closing, a parison is held by the slide blocks 120, The blocks which hold the parison are moved diagonally horizontally to the mold opening/closing direction in accordance with mold clamping, and the parison is moved to a prescribed position to complete the mold clamping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for blow molding used for molding a bottle having a special shape such as a blow molded bottle with a handle.

[0002]

2. Description of the Related Art Conventionally, in blow molding, FIG.
As shown in (a), a vertical tube-shaped molten plastic parison (200) extruded from an extrusion die attached to the tip of the extruder is usually divided into two pieces, which are vertically attached to a blow molding machine. The bottle was formed by being gripped by a blow molding mold composed of a mold (110) and blowing air from a blow pin into the parison.

[0003]

However, in the ordinary molding method in which the above-mentioned mold is vertically mounted on a blow molding machine, the bottle to be molded has a special shape, for example, in the case of a bottle with a handle, FIG. Like parison (20
The parison is extruded vertically from the extrusion die so that the left end of the parison is located on the left side of the pinch-off (112) (an edge portion that cuts and welds the parison) inside the handle, and the parison is split into the split mold (110) (only one side). (Shown) is clamped in a mold, and molded into a mold. The bottom edge of the bottle to be molded is pinched off (111) to reduce stress cracking (environmental cracking) strength at the bottom. In some cases, causing problems in practical use. In order to solve this problem, as shown in FIG. 3 (b), there is a method in which the mold is inclined and mounted on a blow molding machine so that the parison (200) is positioned at the center of the bottom of the bottle. However, the pinch-off (113) on the upper portion hangs from the neck and neck of the bottle to the shoulder and the back of the handle, which may significantly impair the appearance of the molded bottle.

The present invention solves the above-mentioned conventional problems. Even if a bottle having a special shape such as a blow-molded bottle with a handle is molded, the bottle has good stress cracking resistance and good appearance. Is provided.

[0005]

According to the present invention, there is provided a blow molding die which is opened and closed with two split dies, and a pair of opposed dies are provided at positions near the bottom of the cavity of the split die below the pinch-off. A parison gripping slide block is provided movably, each parison gripping slide block is protruded by a predetermined position when the mold is opened, and the parison is gripped by the pair of parison gripping slide blocks during mold clamping. Blow molding characterized by moving the parison gripping slide block in the horizontal direction oblique to the mold opening and closing direction in accordance with the mold clamping and moving the parison to a predetermined position to complete the mold clamping. It is a mold.

[0006]

In the blow molding die according to the present invention, a parison gripping slide block is movably provided at a position near the pinch-off at the bottom of the cavity of the die, and the parison gripping slide block is used to move the lower end of the parison. Since the lower end of the parison can be moved to a predetermined position before gripping and completing the mold clamping, for example, in the case of a handle-equipped bottle, the lower end of the parison is positioned at the center of the pinch-off at the bottom of the mold cavity. Position and can avoid pinching off at the bottom edge of the bottle being molded. Therefore, the molded bottle with a handle has good stress cracking resistance and good appearance.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a blow molding die for a bottle with a handle will be described in detail with reference to the drawings as a blow molding die according to one embodiment of the present invention.

The blow molding die according to the present embodiment comprises two split dies, and as shown in FIG. 1A, a pinch-off (111) at the bottom of the cavity of the split die (110).
And a pair of opposing parison gripping slide blocks (120) are movably provided in the vicinity of the lower part of the vehicle. Then, when the mold is opened, as shown in FIG. 2A, the parison gripping slide blocks (120A, 120B) of the split molds (110A, 110B), respectively.
Is projected by a predetermined position, and during the mold clamping, as shown in FIG.
A, 120B), the lower end of the parison (200) is gripped, and the parison gripping slide block that grips the parison, as shown in FIGS. 2 (b) and (c),
Move the lower end of the parison (200) to a predetermined position (the center position of the mold in the figure) by moving the lower end of the parison (200) in a horizontal direction (indicated by an arrow) with respect to the mold opening and closing direction in accordance with the mold closing. The closing is completed. As a result, as shown in FIG. 1B, the positional relationship between the parison and the mold is such that the upper part of the parison (200) is set so that the left end of the parison is on the left side of the pinch-off (112) inside the handle. And the lower end of the parison (200) is the center position of the pinch-off (111) at the bottom. Since the bottle with the handle to be molded is blow-molded in this state, no pinch-off is applied to the edge of the bottom of the bottle to be molded, and as shown in FIG. The pinch-offs (113) are the mouth, neck and shoulders of the bottle, so that the appearance of the molded bottle is not impaired.
The amount of movement of the parison gripping slide block can be set to a predetermined amount by changing the angle at which the parison grips the slide block.

The bottle with a handle formed by the blow mold of the present embodiment is subjected to a normal transportation test,
A drop strength test and a stress cracking test were performed, and it was found that there was no problem in normal use.

[0010]

According to the present invention, even if a specially shaped bottle such as a blow-molded bottle with a handle is formed by using the blow-molding mold of the present invention, the blow-molding mold is provided at a position near the bottom of the cavity of the mold below the pinch-off. The formed parison gripping slide block allows the lower end of the parison to be moved to a predetermined position for molding, so that the molded bottle has good stress cracking resistance, good appearance, and high commercial value.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a positional relationship between a parison and a die and a position of a parison gripping slide block in a blow molding die for a bottle with a handle according to the present invention.
FIG. 4B shows a state when the mold is opened, and FIG.

FIGS. 2A and 2B are explanatory plan views showing the operation of a parison gripping slide block accompanying mold clamping, wherein FIG. 2A is a state immediately before the parison gripping slide block grips the parison, and FIG. , The parison gripping slide block completely grips the parison, and (c) shows the time when the mold is completely clamped.

FIG. 3 is an explanatory view showing a positional relationship between a parison and a mold in a conventional mold for blow molding a bottle with a handle;
(A) is a case where the mold is mounted vertically, and (b)
Shows a case in which the mold is attached at an angle.

[Explanation of symbols]

 100 mold for blow molding 110 mold split 111 pinch-off at bottom 112 pinch-off at handle inner part 113 pinch-off at upper part 114 pinch-off at mouth and neck 120 parison gripping slide block 200 ...... Parison

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AG07 AH55 CA15 CB01 CK52 CK83 CK90 CL01 4F208 AG07 AH35 LB01 LJ01 LJ14 LJ15 LJ22 LJ29 LN27

Claims (1)

[Claims] 1. A blow molding die having two split dies opened and closed, wherein a pair of opposed parison gripping slide blocks are movable at a position near the bottom of the cavity of the split die below a pinch-off. The parison gripping slide slides by holding the parison with the pair of parison gripping slide blocks during mold clamping, and by projecting the respective parison gripping slide blocks when the mold is opened. A blow molding die, wherein the block is moved obliquely in the horizontal direction with respect to the mold opening and closing direction in accordance with the mold clamping, and the parison is moved to a predetermined position to complete the mold clamping.