JPH07315382A - Plastic bottle - Google Patents

Abstract

PURPOSE:To reduce the recovery cost of a plastic bottle and make its reuse easy by permitting the volume of the plastic bottle to be reduced when it is empty. CONSTITUTION:The body part of a plastic bottle has an expandable and contractible area consisting of a number of circumferential or spiral grooves and each groove consists of the two side parts of different lengths. Each groove has a long side part 1 and a short side part 2 interconnected in an adjoining manner and the length of the short side part comprises 30-95% of that of the long side part. The expandable and contractible area is not expanded largely by a weak force and, only when a strong compressive force is applied in the axial direction, the short side part enters the long side part to cause them to overlap and, only when a strong tensile force is applied, the overlapped part is pulled out to produce a large expansion and contraction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic bottle having a stretchable body. The volume of the plastic bottle of the present invention can be reduced by compressing it with a strong force in the axial direction, and the volume can be increased by pulling it in the axial direction. Due to this elasticity, the plastic bottle of the present invention has a stable small volume when transported empty and a stable large volume when filled with contents. As a result, the plastic bottle of the present invention has an advantage that a long-distance transportation cost before filling is small. Further, there is an advantage that the recovery cost after use is small.

Since the transportation cost before filling is small, the plastic bottle of the present invention can be centrally produced in a large factory, and it is expected that the production cost will be reduced. In addition, since long-distance transportation becomes possible, it becomes easier for small manufacturers of seasonings such as soy sauce and drinking water to use plastic bottles, and the excessive container cost burdened by these manufacturers is reduced. It

The plastic bottle of the present invention can be reduced in volume after use, and can be recovered and utilized from areas where it could not be recovered due to high transportation costs, so it is effectively used as various raw materials for molding. Can be used.

[0004]

2. Description of the Related Art A plastic bottle is light in weight for its strength, and therefore has the advantage of being low cost as a small liquid container, but it is not reused like a glass bottle because of ease of cleaning and fear of deterioration. I haven't been. When considering reuse, it seems difficult to reuse the bottle itself, and it is desirable to reuse it as a raw material resin. However, since plastic bottles are extremely bulky,
The problem is that the cost of collecting waste materials is high and the utility value as raw material resin is poor. For this reason, almost all plastic bottle waste is incinerated as waste, but it is generally disliked because there is a high load on the incinerator. In order to solve this problem, it is necessary to reduce the cost of collecting waste, but it seems effective to reduce the bulkiness of waste first.

It is a common practice to provide a bellows on the body in order to make the volume of the plastic bottle variable. However, as disclosed in Japanese Patent Laid-Open No. 58-134855, this method usually aims at preventing the volume change of the internal liquid due to the temperature change and the liquid leakage due to the concentration of stress due to vibration. . Also, the actual exploitation 56
No. 172517 discloses a technique that allows the volume of a plastic bottle to be changed by means of streak-shaped projections and grooves arranged in the axial direction of the body. However, this technology also does not significantly change the shape of the plastic bottle,
It does not lead to a significant reduction in the waste volume of plastic bottles.

The reason why a large volume change cannot be caused by the streak-like projections and grooves that have been conventionally given to plastic bottles is that conditions in which the shape is stable are concentrated in a specific region and the range is narrow. Therefore, when the external condition is decided, the volume is decided regardless of the history of receiving the force. However, as a characteristic of the plastic bottle, it is desirable that the volume is small when the contents are not contained and the volume is large when the contents are contained. However, if such a volume change is caused by the weight of the contents, the shape of the contents changes due to the decrease of the contents in the process of using the plastic bottle, and it is easy to fall, which is not preferable. The change in volume is caused by another external force, and the shape after deformation is preferably stable until a certain external force is applied.

Many plastic molded products, which change into another stable form by such an external force, are not known except the shape memory resin molded product. As a plastic molded product that changes to another stable form by external force, Japanese Patent Publication No. 51-
No. 33477 discloses a straw that can be bent and fixed in that shape. This straw is a drinking-water pipe made of a thermoplastic material having a flexible region composed of a large number of circumferential grooves in the middle of the pipe, each groove being composed of two side parts of different lengths. , Each groove is connected to each other so that the short side is adjacent to the long side of the adjacent groove, and when the pipe is bent in the flexible region, the short side is recessed into the long side on the contraction side. It is possible to keep the bent state by overlapping with each other.

Japanese Utility Model Publication No. 56-48226 discloses that such a flexible pipe can be manufactured not only for circular pipes but also for polygonal pipes. Such a shape change is possible because it is a tube with a diameter of several mm, such as a straw. When applying this technology to the body of a plastic bottle with a diameter of about 10 cm, the width of the groove must be several cm. It has been considered that such morphological changes do not occur.

[0009]

DISCLOSURE OF THE INVENTION According to the present invention, by reducing the volume of a plastic bottle before and after use to be significantly smaller than the volume during use, the transport cost of empty containers and the recovery cost of waste products are reduced. Therefore, it is an object of the present invention to solve the problems of conventional plastic bottles. Since the plastic bottle is a hollow container, the volume can be reduced by external pressure if the body has a structure such as an elastic bellows. However, in conventional plastic bottles, such external pressure needs to be constantly applied while keeping the volume small, which requires special packaging equipment and expensive packaging materials, and thus solves this problem. It will not be done.

To solve this problem, we have
As a plastic molded product with a stable shape of various types, pay attention to the straw that can be bent, and the groove of this straw is not only bent in a specific shape range,
The present invention has been completed by finding that it is expanded and contracted by fitting and sliding, and is stable in each extended shape and contracted shape. The present invention is a plastic bottle that does not require such special packaging equipment or packaging material and has large stretchability and the ability to retain the stretched shape.

[0011]

According to the present invention, the body has a stretchable region consisting of a number of circumferential grooves, each groove being constituted by two side portions of different lengths. Each is connected to the long side of the adjacent groove such that the short side is adjacent to the long side, and the short side is 30 to the long side.
It has a length of 95%, it does not expand or contract greatly with weak force in the expandable range, and only when a strong compressive force is applied in the axial direction, the short side part invades and overlaps with the long side part, The plastic bottle is characterized in that the overlapped portion is pulled out only when a strong pulling force is applied, and shows a large expansion and contraction.

The present invention also has a stretchable region of one or a plurality of spiral grooves in the body, which groove is constituted by two side portions having different lengths, and the groove of the groove. The short side portion is connected to the long side portion of the next adjacent swivel portion so that the short side portion is adjacent to the long side portion.
It has a length of 95%, it does not expand or contract greatly with weak force in the expandable range, and only when a strong compressive force is applied in the axial direction, the short side part invades and overlaps with the long side part, The plastic bottle is characterized in that the overlapped portion is pulled out only when a strong pulling force is applied, and shows a large expansion and contraction.

The plastic bottle of the present invention is, for example, the first
The groove has a side surface shape as shown in the drawing, and the groove existing in the expandable region has, for example, a cross-sectional shape as shown in FIG. The length of the side portion is obtained by measuring the distance between the central points at which the gradient of the cross section changes and transitioning to the next side portion on a plane passing through the central axis of the body portion. The groove existing in the expandable region may be a large number of grooves that circulate in a cylinder parallel to each other as shown in FIG. 1, or one or a large number of grooves may be arranged like a screw. .

Short side length is 30% of long side length
When shorter than the above, when the plastic bottle of the present invention is compressed in the axial direction, when the short side is fitted to the long side, the strain in the invaginated form is large, so that it is easily scratched and the volume is reduced. Is not preferable because it is small. If it exceeds 95%, the invaded morphology becomes unstable, which is not preferable. The length of the short side is preferably 40 for the long side.
~ 85%. In the present invention, the width of the groove provided in the body is preferably 1 to 25% of the average diameter of the body.

The plastic bottle of the present invention is formed by blow molding or stretch blow molding of a blow moldable resin. The groove can be formed at the same time as molding, or can be pressure-molded in a separate step after molding the bottle.
The raw material resin is preferably polyethylene terephthalate resin, vinyl chloride resin, acrylic resin or the like, but the raw material resin is not essentially limited.

The wall thickness of the bottle does not need to be particularly changed from the conventional one and may be the same level. To form a groove on the body of the plastic bottle of the present invention, a method of using a mold having such a groove or a method of forming a groove by pressure bonding to a heated mold is used. In terms of cost, the method using a die having a groove is superior.

After molding, the plastic bottle of the present invention is compressed in the axial direction to reduce the volume, if necessary, and then sent to a factory for filling the contents. At this time, a slight heat treatment can be performed to stabilize the compressed shape. By this compression, packaging materials and shipping costs required for transportation can be saved, and storage space for empty bottles can be saved.

After use, the plastic bottle of the present invention can be axially compressed to reduce its volume. As a result, the cost of collecting waste products can be reduced, and the waste products can be reused as raw materials for moldings.

[0019]

[Function] The groove provided on the body of the plastic bottle
When compressed in the axial direction, if the groove is symmetrical in the plane containing the axis, the groove is simply reversibly deformed and the angle of the groove is sharpened, but in the case of asymmetry, In a certain range, the side with the long slope presses the side with the short side and falls to the short side. This shape is stable to some extent, and weak force does not restore it to its original shape. The present invention is a plastic bottle that utilizes a groove having two such stable shapes.

[0020]

EXAMPLES Next, the present invention will be described in detail and specifically with reference to Examples.

Example 1 An anvil consisting of a small rotating roller was inserted into a stretch-blow-molded bottle made of polyethylene terephthalate having an inner volume of about 1 liter and an average wall thickness of 47 μm, and an inverted V-shaped heating roller was pressure-bonded from the outside. Then, the body of the bottle was shaped by sandwiching it between the heating roller and the anvil, and a large number of grooves were formed in the body so as to be adjacent to each other.

The length of the long side of the groove is 7 mm in the plane including the central axis of the bottle, and the length of the short side of 5 is measured in the same manner.
mm, (71% with respect to long side), vertical angle of groove 4 after molding
It was 5 °. The number of grooves was 36. Due to the formation of the groove, the internal volume of the bottle was reduced to about 950 ml.

A force of about 1.2 kg was applied in the direction of the central axis of the bottle so that the long side portion was indented between the short side portions of the groove, and this shape was set by blowing hot air at 150 ° C. for 5 seconds. As a result, the outer volume of the bottle was reduced to about 420 ml, and its shape was stable. When water was poured into the bottle in this state, the indentation on the side part disappeared and the internal volume 95
0 ml was restored.

After the water was discarded, the bottle was manually compressed in the direction of the central axis of the bottle. As a result, a lateral indentation occurred again, and the outer volume was reduced to about 420 ml. A crushing test of an empty bottle was performed for a recovery test of a waste product. The crushing rate increased about 1.5 times after compression as compared to before and after formation of grooves.

Example 2 Using the same stretch-blow molded bottle as in Example 1, the shape of the anvil and the heating roller was changed to form grooves, and similarly, the effect of reducing the volume as a bottle by axial compression was obtained. I checked. The results are shown in Table 1.

[0026]

[Table 1]

Example 3 Instead of the bottle in Example 1 in which the groove was formed in the body,
A polyethylene terephthalate bottle molded by using a mold having pleats during stretching of the preform was used.
When the groove of the obtained bottle had substantially the same groove as that of Example 1, the same deformation behavior as that of Example 1 was exhibited with respect to the force in the central axis direction.

Example 4 A bottle provided with one spirally-circulating groove in place of the 36 parallel grooves around the body of Example 1 has substantially the same deformation characteristics as in Example 1. Had.

[0029]

The plastic bottle of the present invention can be compressed by a strong force in the axial direction to reduce its volume, and can be pulled in the axial direction to increase its volume. Due to this elasticity, the plastic bottle of the present invention has a stable small volume when transported empty and a stable large volume when filled with contents. As a result, the plastic bottle of the present invention has an advantage that a long-distance transportation cost before filling is small. Further, there is an advantage that the recovery cost after use is small.

Since the transportation cost before filling is small, the plastic bottle of the present invention can be centrally produced in a large factory, and it is expected to reduce the production cost. In addition, since long-distance transportation becomes possible, it becomes easier for small manufacturers of seasonings such as soy sauce and drinking water to use plastic bottles, and the excessive container cost burdened by these manufacturers is reduced. It

The plastic bottle of the present invention can be reduced in volume after use, and can be recovered and used from areas where it could not be recovered due to high transportation cost in the past.
It can be effectively used as various molding raw materials.

[Brief description of drawings]

FIG. 1 is a schematic view showing one embodiment of the shape of the body portion of the plastic bottle of the present invention.

FIG. 2 is a cross-sectional view illustrating details of a groove portion.

[Explanation of symbols] 1 long side of groove 2 short side of groove

Claims (3)

[Claims] 1. A body portion having a stretchable region composed of a large number of circumferential grooves, each groove being constituted by two side portions having different lengths, each groove being an adjacent groove. Are connected to each other such that the short side is adjacent to the long side, the short side has a length of 30 to 95% with respect to the long side, and is weak in the stretchable region. It does not expand and contract greatly with force, the short side part invades and overlaps with the long side part only when a strong compressive force is applied in the axial direction, and the overlapped part is pulled out only when a strong tensile force is applied, A plastic bottle characterized by large expansion and contraction. 2. The body has an expandable region composed of one or a plurality of spiral grooves, and the grooves are constituted by two side parts having different lengths, and the grooves are adjacent to each other. The short side portion is connected to the long side portion of the next turning portion so as to be adjacent to the long side portion, and the short side portion has a length of 30 to 95% with respect to the long side portion. Does not expand or contract with a weak force, only when a strong compressive force is applied in the axial direction, the short side part invades and overlaps with the long side part, and the overlapped part is pulled out only when a strong tensile force is applied. A plastic bottle characterized by exhibiting large expansion and contraction. 3. The plastic bottle according to claim 1, wherein the width of the groove formed in the body is 1 to 25% of the average diameter of the body.