JPH04138241A - Molding method for hollow container with handle - Google Patents

Abstract

PURPOSE:To eliminate heat deformation of a hollow container and shortage of cooling of a handle resin contact section by jetting a refrigerant locally through a refrigerant introducing rod on the inner face of a container corresponding to a zone where handle molding resin is brought into contact with the hollow container. CONSTITUTION:PET resin is introduced into a resin path regulated by first and second forming channels 34 and 36 and a peripheral side face opposite to a bottle 22 through a handle forming cavity 38 to injection mold an upper section ring 42, a lower section ring 44 and a handle section 46. Spraying is continued locally from first and second jetting outlets 56 and 58 of a refrigerent introducing rod 52 all over the injection molding process of a handle 40 to cool sufficiently a zone in which PET resin as a molding resin material of the handle 40 is brought into contact with the peripheral side face of the bottle 22. As a result, heat deformation of the bottle 22 molded with PET as the material of same kind as the handle molding resin material can be prevented securely. Also the handle molding resin material can be prevented securely from leaking from the given resin path.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for molding a hollow container with a handle, and in particular, to prevent a reduction in the mechanical strength of one handle that is thermally deformed during injection molding of the handle. Regarding the method.

[Prior Art] Bottles made of polyethylene terephthalate (hereinafter abbreviated as PET), for example, which are formed by biaxial stretch blow molding, enable the molding of large resin bottles, and are easy to handle. Bottles with handles are also being molded.

Regarding the manufacturing method of this kind of bottle with a handle,
2-181180. Tokukai Showa 6! lt-292144, JP-A-64-20126, International Publication Number WO901009
There are some disclosed in various publications such as No. 83 (Patent Application Publication Hei 2-501556).

After the bottle is stretch-blow-molded with two wheels, the circumferential side of the bottle is filled annularly or partially with half-molded resin using a cavity, and the handle is injection-molded to be welded and integrated with the hollow container. It is something.

As the molding resin material for this type of handle, materials such as polypropylene (PC) and polyethylene (PE), which have a relatively low viscosity and have a lower molding temperature than PET, which is the molding resin for the bottle, are used.

[Problem to be solved by the invention] By the way, it has been confirmed that the following problem occurs when a molding material whose molding temperature is similar to the resin material for bottle molding is used as the resin material for handle molding. .

That is, since the resin material for forming the handle flows in contact with the circumferential side of the bottle, the contact portion of the bottle is thermally deformed by the heat of the resin material for forming the handle. In this case, not only the appearance quality is impaired due to thermal deformation of the bottle, but also resin leakage is caused due to deformation of the peripheral side of the bottle that defines the resin path for forming the handle. Furthermore, the contact area between the handle and the bottle is not sufficiently cooled and heat welds, resulting in a decrease in strength.

Further, especially when PUT is used as the resin for molding the handle, when the contact area between the handle and the bottle is slowly cooled, there arises a problem that the area becomes white and crystallized, impairing the appearance and causing insufficient strength.

Such problems may be solved by selecting a handle molding resin that has a low molding temperature. However, in recent years, there has been a trend towards plastic recycling in the bottle industry as well, and in order to promote recycling, it is required that the bottle and handle be molded from the same type or similar material, and in this case, the molding temperature of the resin material for molding the handle is will be close to the molding temperature of the bottle material.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and even if the molding temperatures of the resin materials of the hollow container and the handle are similar, the thermal deformation of the hollow container and the resin contact part of the handle can be prevented. To provide a method for molding a hollow container with a handle, which can eliminate insufficient cooling, have excellent appearance quality, and ensure mechanical strength of the handle.

[Means for Solving the Problems] A first invention is a method of stretch-blow-molding a hollow container and then injection-molding a handle on the circumferential side of the hollow container to integrate the handle, which comprises: The method includes the step of inserting a cooling medium introduction rod into the hollow container and locally spouting the cooling medium through the cooling medium introduction rod onto the inner surface of the container corresponding to the area where the handle molding resin contacts the hollow container. It is characterized by

A second invention is a method for integrating a handle by injection molding on the circumferential side of the hollow container after the hollow container is stretch-blow-molded. The present invention is characterized in that a rib that is convex toward is molded, and then a resin path for molding the handle defined by the circumferential side surface of the hollow container having the rib and the cavity for molding the handle is filled with resin.

[Function] According to the first invention, during injection molding of the handle, the cooling medium inserted into the hollow container is introduced to the inner surface facing the circumferential side of the hollow container that comes into contact with the resin material for molding the handle. Since the cooling medium is locally sprayed by the rod for cooling, deformation of the hollow container due to the heat of the handle molding resin can be prevented. In addition, since it is possible to achieve local cooling of the area, it is possible to prevent the mechanical strength of the heat welded part from decreasing due to insufficient cooling, and furthermore, in the case of PET resin, it is possible to prevent whitening and crystallization and the resulting decrease in mechanical strength. .

According to the second invention, the ribs convex toward the outside are formed on the circumferential side of the hollow container that defines the inner resin path of the handle, so that the cross-sectional area of the handle resin path is reduced, and the handle is formed. It is possible to reduce the amount of heat of the resin material used. Therefore, it is possible to solve the problem of preventing thermal deformation of the hollow container, which is the same problem as the first invention, and also to solve the problem of insufficient cooling due to the small amount of heat, thereby preventing whitening crystallization and a decrease in mechanical strength of the heat-welded part. obtain. Furthermore, in the second aspect of the invention, since the convex ribs also act as reinforcing materials to prevent deformation of the hollow container, it is possible to prevent deformation of the hollow container due to resin pressure during filling with the handle-forming resin.

[Example 1] Hereinafter, an example of the method of the present invention will be specifically described with reference to the drawings.

FIG. 2 shows the process of biaxially stretching blow molding the bottomed parison 10 in the blow mold 16.

Here, before the bottomed parison 10 is conveyed to this blow molding mold 6, it is injection molded using, for example, PET resin using a parison injection molding mold, and then passed through a temperature control process and then transferred to this blow molding mold 16. transported. This parison 1
The conveyance of the parison 10 is carried out by holding the neck portion 12 of the parison 10 by a neck mold 14, which is one of the parison injection molds.

The blow molding mold 16 is composed of two split molds each having a cavity 16 a that follows the outer shape of the final bottle 22 . A blow core mold 18 is inserted into the neck part of the parison 10 disposed in the blow mold] 6, and a stretching rod 20 is supported along the central axis direction of the blow core mold 8 so as to be freely raised and lowered. There is. parison 1
In order to biaxially stretch blow mold the parison 10, the stretching rod 20 is brought into contact with the inner surface of the bottom wall of the parison 10 and driven downward, and blow air is blown from the blow core mold 18 to stretch the parison 0 in its axial direction. and by radially orienting the two wheels.

Here, by the stretching blowing process of the bottle 22, the bottle 22
An annular convex rib 24 that is convex in the radial direction is formed on the circumferential surface of the bottle 22 at approximately the middle position in the height direction.

The bottle 22 is taken out from the blow molding mold 6, which is a split mold, and then transported by the neck mold 14 to the next step, a handle injection molding step.

FIG. 1 shows the handle injection molding process.

In the figure, the handle forming mold 30 is composed of two split molds similarly to the blow molding mold 16, and has a bottle accommodating cavity 32 in which the bottle 22 can be accommodated. Furthermore, a first . It has a second forming groove 34°36. Furthermore, this first. Second
Handle molding cavity 3 communicating with molding grooves 34 and 36 of
8 is located on the parting surface of the handle mold 30.

Here, the above-mentioned 1. The inner surface of the second molding groove 34, 36 is formed in a shape that provides the outer shape of the handle 40 to be injection molded, and the open end side of this groove is formed as shown in FIGS. 3(A) and (B). As such, leak prevention ribs 34a, 34b and 36a, 36b are provided to prevent leakage of the resin material for molding the handle. Each leak prevention rib 34a, 34b, 36
a and 36b are respectively inclination angles θ (for example, θ-45°)
The leak prevention ribs 34a, 34b have a height H] -0,3-0,5-. On the other hand, the leak prevention rib 36a36b is
Its height is H2-0.5 to 1 dragon. The leak-preventing ribs 34a to 36b each protrude from the cavity surface of the handle mold 30, so they act to press the circumferential surface of the bottle 22 disposed inside the bottle 22.
The leakage of the resin for molding the handle can be reliably prevented by the close contact with the peripheral surface of the handle.

The handle mold 30 has a hot runner 48 that communicates with the handle molding cavity 38.
The handle 40 consisting of the upper ring 42, the lower ring 44, and the grip part 46 can be injection molded by filling the resin material for molding the handle, such as PET, through the handle 48.

A core mold 50 for conveying and discharging a refrigerant is inserted into the neck portion 12 of the bottle 22 which is placed inside the handle mold 30 .

This refrigerant feeding/discharging core mold 50 supports a refrigerant introducing rod 52 along its central axis so as to be movable up and down. The refrigerant introduction rod 52 has a refrigerant introduction passage 54 whose end is sealed along its axial direction, and the first refrigerant introduction passage 52 of the handle mold 30 has a refrigerant introduction passage 54 whose end is sealed. The first molding grooves 34 and 36 are open at multiple locations in the circumferential direction at positions facing the second molding grooves 34 and 36. It has a second spout 56,58. Further, the refrigerant feeding/discharging core mold 50 has an exhaust path 60 around the refrigerant introduction rod 52 . A throttle valve 62 is connected to the exhaust path 60, and by adjusting the throttle valve 62, the internal pressure of the bottle 22 can be maintained at a predetermined level during injection molding of the handle 40.

Next, the injection molding process for the handle 40 will be explained.

The bottle 22 held by the neck mold 14 is placed in close contact with the bottle accommodation cavity 32 of the handle mold 30 by driving the handle mold 30, which is a split mold, to close. Here, number one. Leak-proof ribs 34a, 34b, 36a, and 36b that protrude inward from the container storage cavity 32 are formed on the upper and lower edges of the second molding groove 34.36. The circumferential surface of that portion of the bottle 22 is pressed, and reliable contact between each rib and the circumferential surface of the bottle 22 can be realized.

Thereafter, the core mold 50 for refrigerant transport and discharge is inserted into the neck portion 12 of the bottle 22, and the refrigerant introduction rod 52 is driven downward along the core mold 50 for refrigerant transport and discharge, and is stopped at a predetermined position. Ru. This predetermined position refers to the refrigerant introduction rod 5
1st in 2. The second spout 56 , 58 is in a position opposite to the first and second forming grooves 34 , 36 of the handle forming mold 30 .

Next, a refrigerant, such as room temperature air, is introduced into the bottle 22 via the refrigerant introduction rod 52. The functions of the air introduced into the bottle 22 by the refrigerant introduction rod 52 are to prevent deformation of the bottle 22 due to the resin pressure during injection molding of the handle 40 (inner pressure maintenance effect),
This function also serves to prevent thermal deformation (cooling effect) of the bottle 22 due to the heat of the injection molded resin of the handle 40. The air introduced from the refrigerant introduction rod 52 is initially, for example, 20 k
g/c-, this air is introduced into bottle 2
2, and the outer surface of the bottle 22 is brought into close contact with the container accommodation cavity 32 of the handle mold 30. Further, this air is exhausted along an exhaust path 60 of the refrigerant supply/discharge core mold 50, and by adjusting a throttle valve 62 connected to this exhaust path 60, the pressure inside the bottle 22 is reduced to 18 k, for example.
g/c-. Therefore, the internal pressure of the bottle 22 is maintained throughout the injection molding process of the handle 40. The leak-preventing ribs 34a to 36b in the second molding grooves 34, 36 are constantly pressed against the outer surface of the bottle 22, and this action can prevent leakage of the resin material for molding the handle.

After the internal pressure inside the bottle 22 is maintained at a constant value, P as a handle molding resin material is passed through a hot runner 40.
Filled with ET resin. This PET resin is passed through the handle molding cavity 38 into the first and second molding grooves 34 and 36.
and the opposite circumferential sides of the bottle 22, and is introduced into the resin path defined by the upper ring 42. The lower ring 44 and grip 46 will be injection molded.

Throughout the injection molding process of the grip 40, the first . Local blowing of air continues from the second jet ports 56 and 58. By continuing to blow fresh air locally like this,
The bottle 22 is made of PET resin, which is the molded resin material of the handle 40.
It becomes possible to sufficiently cool the area that comes into contact with the peripheral side of the.

As a result, PET, which is the same type of resin material as the handle molding resin material,
It is possible to reliably prevent thermal deformation of the bottle 22 that has been molded.

By preventing such thermal deformation of the bottle 22,
In combination with the effect of the leak-proof ribs 34a to 36b pressing against the circumferential side surface of the bottle 220, it is possible to reliably prevent the handle molding resin material from leaking from the predetermined resin path.

Furthermore, by locally blowing fresh air, cooling of the contact area between the handle 40 and the bottle 22 can be promoted, and the strength of the heat-welded part between the bottle 22 and the handle 40, which was caused by insufficient cooling of the contact area in the conventional case, can be improved. The drop can be reduced.

In particular, when the handle molding resin material is PET resin,
Although whitening and crystallization are likely to occur due to slow cooling of PET resin, local cooling as in this example can reduce PET resin.
The transparency of the ET resin can be ensured, and it is also possible to prevent a decrease in the mechanical strength of the heat-welded part due to whitening.

As described above, the bottle 22 with the handle 40 molded by the method of this embodiment has excellent appearance quality because the bottle 22 undergoes little thermal deformation, and the leakage of the resin material for molding the handle is also reduced, resulting in an improved product yield. Furthermore, it becomes possible to integrally mold the handle 40 with excellent transparency and mechanical strength with the bottle 22.

FIG. 4 shows another embodiment of the method of the invention.

The bottle 70 shown in the figure has ribs 76, 78 that are not annular but only partially convex at approximately the same location in the circumferential direction on the shoulder 72 and the side wall 74. The handle mold 80 has a bottle accommodation cavity 80a that accommodates the bottle 70, and the handle molding die 80 has a handle forming cavity 82 that is opened to communicate with the bottle accommodation cavity 80a at a position facing the convex ribs 76,78. have. The handle 84, which is molded by filling the cavity 82 with resin, does not have an upper and lower ring, unlike the above embodiment, and is heated at two points on the base ends 84a and 84b of the handle 84 or on the bottle 70. Welded and integrated.

The refrigerant feeding/discharging core mold 90 has a refrigerant introducing rod 92 similar to the above embodiment, and this refrigerant introducing rod 92 has, for example, a single first opening at a position substantially opposite to the convex ribs 76 and 78. ．． It has second jet ports 96 and 98, which communicate with a refrigerant introduction passage 94 located at the axial center. Further, the refrigerant feeding/discharging core mold 90 has two parts in which an exhaust path 100 is formed around the refrigerant introduction rod 92, and this exhaust path 100.
The point that is connected to a throttle valve (not shown) is the same as in the above embodiment.

In this embodiment, the contact part where the handle 80 contacts the bottle 70 is not annular but a part of the circumferential direction.
6 can be locally cooled by air, and the same functions and effects as in the above embodiment can be achieved.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the invention.

For example, in each of the above embodiments, air is used as the refrigerant, and this air is also used to maintain the internal pressure of the bottle 22 or the bottle 70, but the same fluid is not necessarily used to perform both the cooling action and the internal pressure maintaining action. . In order to increase the cooling effect, a refrigerant at room temperature or lower may be used, and another fluid may be used to maintain the internal pressure.

[Effects of the Invention] As explained above, according to the method of the present invention, local cooling is achieved by spraying the refrigerant through the refrigerant introduction rod onto the circumferential side of the hollow container that comes into contact with the resin for molding the handle. In addition, by forming convex ribs on the surface of the container where the handle is formed, the amount of heat held by the resin material of the handle can be reduced and reinforcement can be achieved to prevent deformation of the container. Even when molded with the same type of resin material with similar temperatures, it can prevent various problems caused by thermal deformation of the container and insufficient cooling of the contact parts, has a good appearance quality, has a high yield, and has excellent mechanical strength of the handle. A hollow container with a handle can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a configuration for realizing a handle forming process in an embodiment method of the present invention; FIG. 2 is a sectional view of a configuration for realizing a container stretch blow molding process; FIG. 3(A); (B) is A of FIG. 2, respectively. An enlarged view of part B, FIG. 4 is a sectional view of a configuration for realizing the handle forming step in another embodiment method of the present invention. 10... Parison 16... Blow molding mold 22.70
... Bottle 24.76.78 ... Convex rib 30.80 ... Handle mold 40.82 ... Handle 52.92 ... Refrigerant introduction rod 56.58, 94.98 ... Spout port Agent Patent attorney Inoue - (2 others) Figures (A) (B) Figures

Claims (2)

[Claims] (1) In a method in which a handle is integrally formed by injection molding on the circumferential side of the hollow container after stretch blow molding the hollow container, a cooling medium introduction rod is inserted into the interior of the hollow container during injection molding of the handle. A method for molding a hollow container with a handle, comprising a step of locally spouting a cooling medium through the cooling medium introduction rod onto the inner surface of the container corresponding to the area where the handle molding resin contacts the hollow container. . (2) In a method in which a handle is integrally formed by injection molding on the circumferential side of the hollow container after the hollow container is stretch-blow-molded, during the stretch-blow-molding, the handle is formed outward on the circumferential side of the container. A hollow container with a handle, characterized in that a convex rib is molded, and then a resin path for molding a handle defined by a circumferential side surface of the hollow container having the rib and a cavity for molding the handle is filled with resin. Molding method.