JPS649225B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a polyester container with a handle, and more particularly to a biaxially stretched blown polyester container with a handle having a hollow portion communicating with the main portion of the container.

(Prior Art) Conventionally proposed biaxially stretched blown polyester containers having hollow handles are made by, for example, heat-sealing a preliminary biaxially stretched blow molded product at a semi-molten stage to form a handle original shape. This is then biaxially stretched and blow-molded again to obtain a predetermined shape (Japanese Unexamined Patent Publication No. 74840/1984).

(Problem to be Solved by the Invention) In polyester containers made by such a method, the heat-sealed portion is formed not in a completely molten state but in a semi-molten state, so the heat-sealed portion is formed in a liquid-tight state. The problem is that it is difficult to form a liquid, and as a result, the contents are likely to leak.

The present invention provides a biaxially stretched blown polyester container with a handle that ensures liquid-tightness, particularly at the sealing part on the circumferential surface of the hole between the hollow handle and the main part of the container. aim at something.

Another object of the present invention is to provide a biaxially stretched blown polyester container with a handle, in which deformation such as bending of the hollow handle is difficult to occur even if the container has a relatively large capacity and a relatively thin wall. The purpose of

(Means for Solving the Problems) A biaxially stretched blown polyester container with a handle of the present invention is a biaxially stretched blown polyester container equipped with a handle having a hollow portion that communicates with the main portion of the container. Along the circumferential surface of the hole between the main parts of the container, a peripheral reinforcing part is formed by curving the fins formed by the outer extensions of the walls of the container in two close layers in a direction substantially perpendicular to the hole. The edge portion of the peripheral edge reinforcing portion is sealed by heat fusion.

In this specification, polyester refers to a thermoplastic saturated polyester resin mainly composed of polyethylene terephthalate (hereinafter also referred to as polyethylene terephthalate).

This resin has a high melting point (the melting point is approximately 265°C), and when the temperature exceeds the recrystallization start temperature (approximately 130°C), crystallization progresses and the resin tends to turn white and become brittle. Therefore, it is more difficult to heat-seal than polyolefin resins such as polyethylene.

(Function) Although the handle of the handle-equipped biaxially blown polyester container of the present invention is hollow, the outer diameter of the two closely spaced container walls extends along the circumferential surface of the hole between the handle and the main part of the container. Since the peripheral reinforcing part is formed by curving the fin part in a direction approximately perpendicular to the hole, the reinforcing effect of the peripheral reinforcing part, which has an approximately J-shaped cross section, allows the container to be relatively large. Even if the handle has a large capacity and is relatively thin, when the handle is held by hand, it is unlikely to be bent or otherwise deformed.

The edges of the peripheral reinforcement are sealed by heat fusion, and this sealing is done by using a cutter heated above the melting point of the polyester to form two closely spaced container walls, leaving the fins intact. It is formed by punching and cutting the outer extension of the section. Therefore, the sealing time is extremely short compared to the usual hot plate type heat sealing (thermal fusion), and since the seal is formed at a temperature above the melting point, pinholes etc. are less likely to occur during sealing. Both crystallization progresses,
It has excellent liquid tightness because it does not whiten or become brittle. When the seal portion becomes brittle, it easily cracks due to external force, impairing liquid tightness.

(Example) Reference numeral 1 in FIGS. 1 and 2 shows a biaxially stretched blown polyester container with a handle before the fin portion 6 is formed on the peripheral edge reinforcement portion 6'. A hole 4 is formed between the handle 3 and the handle 3 for insertion of a fingertip when grasping the handle 3.

A hollow part 5 is formed in the handle 3, and the hollow part 5 communicates with the inside of the container main part 2, so that contents such as liquid are also accommodated inside the handle 3, that is, in the hollow part 5. It is configured as follows.

A fin portion 6 is formed along the circumferential surface of the hole portion 4, and the fin portion 6 is connected to a close contact portion 7 consisting of two layers in which the wall portion 2a of the main portion of the container and the outer extension portion of the handle wall portion 3a are in close contact with each other. It consists of an edge portion 8 sealed by fusion.

If the handle 3' is sealed by a heat-sealed part 9 in the wall 3'a, as shown in FIG. 3, for example,
Due to the above-mentioned thermal properties of polyester, it is difficult to achieve complete heat fusion without pinholes, cavities, or embrittlement due to recrystallization, which tends to result in an incomplete seal, and the content liquid etc. This can easily lead to leakage of water or intrusion of outside air.

As shown in FIG. 4, the fin part 6 is formed into a peripheral reinforcing part 6' which is curved in a direction substantially perpendicular to the hole part 4 and has a substantially J-shaped cross section.
This results in an axially stretched blown polyester container.

By forming the peripheral edge reinforcement part 6' in this way, the area of the hole 4 becomes larger, and the relatively thin edge part 8 does not directly touch the inside of the fingers when gripping, so that gripping the handle 3 becomes easier. This becomes easier, and the cross-sectional effect of the approximately J-shaped cross section further increases the reinforcing properties.

To explain more specifically, the body wall of a biaxially stretched blown polyester container is generally formed thin (for example, 0.2 to 0.3 mm), but the handle 3 is thin like this and is relatively thin. Even in the case of containers with large capacity (e.g. 2 to 3 liters),
The reinforcing effect of the peripheral edge reinforcing portion 6' prevents the handle 3 from deforming (such as bending or denting).

In order to achieve the above effects, the width of the fin part 6 before forming the peripheral reinforcing part 6' is usually 0.5 to 4.
Preferably, it is mm. If it is smaller than 0.5mm, it is difficult to achieve the above effect;
This is because even if the size is larger than mm, the above-mentioned effect will not increase much, and on the contrary, the area of the hole 4 will become smaller, causing a problem that it will become difficult to grip.

The method for manufacturing the container of the present invention as described above will be explained below.

FIG. 5 shows the inner surface of a biaxial stretch blow molding mold 11 used for manufacturing the container of the present invention, in which the mold 11 has a neck mold 12, a body mold 13, and a body mold 13.
and a bottom mold 14. The body mold 13 is composed of two half molds, 15 is a cavity, and 16 is a surface where the half molds are to be in contact with each other. 12a, 13a
and 14a are the inner surface (cavity surface) of the neck mold 12, most of the body mold 13, and the bottom surface 14, respectively.
It shows the cooling holes through which cooling water passes to keep the temperature lower than the glass transition point (approximately 80°C) of polyethylene terephthalate after stretching.

A pair of opposing pressing members 17 are provided at positions on the body mold 13 corresponding to the holes 4 and fins 6 of the container 1, and the pressing members 17 are driven by a drive mechanism (for example, a pneumatic cylinder) not shown. It is capable of reciprocating along the sleeve 18 in a direction perpendicular to the half-shell type contact surface 16 (FIG. 6). sleeve 1
8 and the main body of the body type 13 are heat-resistant heat insulating sheets 19
(for example, a fluororesin sheet). Heating bodies 21 and 22 are built into the pressing member 17 and the sleeve 18, respectively.
The pressing surface 17a (having the same shape as the outline of the fin) and the inner surface 18a of the sleeve 18 are 2
After axial stretch blow molding, the temperature is maintained at a temperature higher than the glass transition point of polyethylene terephthalate and preferably lower than the recrystallization start temperature. Note that the holding temperature does not prevent the recrystallization start temperature from occurring within a range in which whitening does not occur. As is clear from FIG. 6, the trunk-shaped inner surface 13b, the inner surface 19a of the heat insulating sheet,
It is preferable that the sleeve inner surface 18a and the pressing surface 17a form a continuous surface with no step difference during biaxial stretch blow molding. This is to ensure that the outer surface of the container 1 is as smooth as possible. Reference numeral 20 is a biaxially stretched blow-molded body, 20a is a wall corresponding to the wall 2a of the main part of the container 1, 20b is a wall corresponding to the wall 3a of the handle, and has a cross section of approximately half. It has a circular shape and is in contact with the inner surface 13b of the barrel type. An intermediate wall portion 20c, which is parallel in cross section between the walls 20a and 20b (however, the wall portion 20a side is slightly widened), is connected to the sleeve inner surface 18a and the pressing surface 1.
It is in contact with 7a. Therefore, the walls 20a and 20b of the molded body 20 immediately after the completion of molding are both rapidly cooled by the inner surface 13b of the body mold and have a temperature lower than the glass transition point, making them difficult to deform, while the intermediate wall 20c has a temperature higher than the glass transition point. Since it is held, it can be deformed.

Using the mold 11 described above, the container 1 of the present invention is manufactured, for example, as follows.

First, an injection-molded polyethylene terephthalate parison (not shown) heated to a temperature above the glass transition point and below the recrystallization start temperature, preferably about 90 to 110°C, is placed in a mold of the type shown in Fig. 5. The neck is held with a neck mold 12. At this time, the pressure surface 17a of the cylinder and the inner surface 18a of the sleeve which are to be in contact with the intermediate wall 20c are set at the glass transition point (approximately 80
℃) and preferably lower than the recrystallization start temperature, while the other inner surface of the mold is maintained at a temperature lower than the above-mentioned glass transition point (approximately 80°C). Thereafter, a stretching rod (not shown) is press-fitted, and biaxial stretching blow molding is performed by a conventional method to form the molded body 20. Intermediate wall portion 20 of molded body 20
When the body wall portions 20a and 20b other than c become lower than the glass transition point (approximately 80° C.), the pressing member 17 is immediately pushed into the body mold 13, and the pressing surface 17a is pressed as shown in FIG. intermediate wall portion 20 in contact with
The portion c' is brought into close contact to form a close contact portion 23.
At this time, the portion 20c'' of the intermediate wall that is to become the main part of the container and the portion 20c that is to be the handle are also at a temperature above the glass transition point, so they are easily deformed, while the other body wall parts Since 20a and 20b are at a temperature lower than the glass transition point and do not deform, the main part 2 of the container and the handle 3 are defined around the part to become the hole 4, as shown in FIG.
That is, due to the deformation of the intermediate wall portion 20c, the hole portion 4
A peripheral surface is formed.

Next, the pressing member 17 is returned to its original position (it may be returned later), the mold 11 is opened, and the molded body 20' in which the close contact portion 23 is formed is taken out. Rear blade part 2
4 and a die 25, and the temperature near the tip of the blade portion 24 is heated to a temperature higher than the melting point of polyethylene terephthalate (approximately 264° C.) by a built-in heater 26, etc., by punching and cutting the close contact portion 23. Thus, the hole 4 and the fin 6 are formed. The edge portion 8 of the fin portion 6 is heat-sealed to ensure a seal. Immediately after removing the cutter 27, it is preferable to rapidly cool the area around the edge portion 8 by water cooling or the like as necessary to prevent the area from whitening.

Next, the fin portion 6 is bent in a direction approximately perpendicular to the hole portion 4 using a suitable tool at a temperature higher than the glass transition point of the polyester resin and preferably lower than the recrystallization start temperature to form a peripheral edge reinforcement portion. 6' is formed.

(Effects of the Invention) The handle-equipped biaxially stretched blown polyester container of the present invention has the following effects.

(a) Because the molecules are oriented by biaxial stretch blow molding, the container has excellent container performance such as transparency, gas barrier properties, strength, and impact resistance. Since the hollow part communicates with the main part of the container, compared to a case where the handle is solid, the internal capacity is larger by the amount corresponding to the hollow part, and the amount of material used can be reduced.

(b) Since a peripheral reinforcing part is formed along the circumferential surface of the hole, the reinforcing effect allows the container to have a large capacity.
In addition, even if the handle is thin, deformation such as bending or denting of the handle is unlikely to occur when the handle is gripped.

(c) The peripheral edge reinforcement part is formed by curving the fin part in a direction approximately perpendicular to the hole part, so the area of the hole part is larger, and the relatively thin edge part is difficult to grip when gripping the handle. The handle is relatively easy to grasp because it does not directly touch the inside of the fingers.

(d) Since the edge of the peripheral reinforcement part is sealed by heat fusion, defects such as pinholes and embrittlement are less likely to occur in the sealed part, and liquid tightness is ensured, preventing leakage of the liquid content and leakage of outside air. Problems such as intrusion are unlikely to occur.

[Brief explanation of drawings]

FIG. 1 is a front view of an example of a container having a fin before the peripheral reinforcing portion of the present invention is formed, and FIG. 2 is a cross-sectional view taken along the line - in FIG. 1, showing the structure near the handle. FIG. 3 is an example of a cross-sectional view of a hollow handle of a container as a comparative example, and FIG. Corresponding cross-sectional views, FIG. 5 is a vertical cross-sectional view along the contact surface of the split-body mold of an example of the mold used for manufacturing the container of the present invention, and FIG. 6 is a cross-sectional view taken along the line - in FIG. 7 is a cross-sectional view of the mold showing the state immediately after biaxial stretch blow molding, FIG. 7 is a cross-sectional view of the mold showing the state in which the close contact part is formed after molding in FIG. 6, and FIG. 8 is a drawing showing the state immediately after biaxial stretch blow molding. FIG. 8 is a cross-sectional view at the same height of the molded body (container) as FIG. 7 for showing the state of formation. 1... Biaxially stretched blown polyester container, 2...
Container main part, 3...handle, 4...hole, 5...hollow part, 6...fin part, 6'...peripheral reinforcement part, 8...
Edge part, 23... Close contact part, 27... Cutter.

Claims (1)

[Scope of Claims] 1. In a biaxially oriented blown polyester container equipped with a handle having a hollow part communicating with the main part of the container, two layers of A circumferential reinforcing portion is formed by fins formed by the outer extensions of the wall portions of the container being in close contact with each other and curved in a direction substantially perpendicular to the hole, and an edge portion of the circumferential reinforcing portion is formed by heat melting. 1. A biaxially stretched blown polyester container with a handle, characterized in that the container is sealed with a polyester resin. 2. The edge portion sealed by heat fusion is cut by punching the outer extension of the wall of the container using a cutter heated above the melting point of the polyester, leaving the fin portion. A biaxially stretched blown polyester container with a handle according to claim 1, which is formed by