JP3231879B2 - Method for manufacturing resin bottle container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a bottle made of resin.

[0002]

2. Description of the Related Art In many cases, a product name, a maker name, and the like are printed on the outer surface of a bottle container, or a label or the like on which these are printed is attached. Considering printing or attaching a label to the surface of the bottle container in this way, it is preferable that the surface of the bottle container be flat.

However, in the case of a bottle container having a relatively wide flat surface or a bottle container having a large curved surface with a large radius of curvature, in order to increase the rigidity, the entire bottle container or a portion requiring reinforcement (for example, a hand-held portion) is required. On the surface of the substrate).

[0004]

If the surface of the bottle container is provided with uneven ribs as described above, it becomes impossible to print or attach a label to the surface of the bottle container, or the space for performing these operations is limited. There was a problem.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a manufacturing method suitable for manufacturing a resin bottle container having a substantially smooth outer surface and high rigidity. Aim.

[0006]

The present invention has the following features to attain the object mentioned above. In the bottle container manufactured by the present invention, the outer peripheral surface of the wall portion in the storage portion for storing the contents is formed substantially smooth, and the inner peripheral surface is formed in a corrugated shape. With this configuration, the thick portion and the thin portion are alternately formed on the wall portion in the axial direction of the housing portion, and the rigidity of the housing portion is increased. The thick portion and the thin portion may be provided over the entire wall portion of the housing portion, or may be provided partially only at a portion requiring reinforcement. Further, the cross-sectional shape of the housing portion is not limited to a circular shape, and various shapes such as an elliptical shape and a rectangular shape can be adopted.

In order to manufacture the bottle container having the above structure, a blow molding method having the following structure is preferred. at first,
A preformed product in which a portion corresponding to the storage portion has a substantially uniform thickness, and a hollow mold having a substantially smooth forming surface are prepared. The preform is heated at substantially the same temperature in the circumferential direction and alternately in the axial direction such that a high-temperature heating section and a low-temperature heating section are generated.

[0008] The high-temperature heating section is performed, for example, by disposing a plurality of heaters in the vicinity of the preform and separated from each other in the axial direction, and the low-temperature heating section, for example, blows cool air from between the heaters toward the preform. It is performed by blowing air.

Next, the preform is set in the hollow mold, and air is blown into the preform to expand the preform. The outer peripheral surface of the preform is molded into a substantially smooth shape by the molding surface of the hollow mold. On the other hand, since the high-temperature heating part of the preform has a higher stretchability than the low-temperature heating part, the high-temperature heating part is stretched thinner than the low-temperature heating part, and the peaks and valleys are formed on the inner peripheral surface of the preform. Part occurs. When this is cooled and solidified and taken out of the mold, the resin bottle container having the above configuration is completed.

[0010] Incidentally, the preform refers to a parison or a preform. As the material of the preform, polyethylene terephthalate is suitable, but other resin materials can also be used.

[0011]

According to the method of manufacturing a resin bottle container of the present invention, a thick portion is provided on a wall portion of a storage portion for storing contents, thereby increasing the rigidity of the storage portion and smoothing the outer peripheral surface of the wall portion. In order to provide a bottle container in which the outer peripheral surface is printed or the label can be easily attached, the waveform of the inner peripheral surface of the wall portion of the housing portion can be formed into a desired shape.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, a bottle container formed by the manufacturing method according to the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of a resin bottle container formed by the manufacturing method according to the present invention. This bottle container 1 is a so-called PET bottle formed of polyethylene terephthalate, and has a storage section 2 for storing contents such as liquid food, and a pouring section 3. A flange portion 4 projects in a ring shape between the housing portion 2 and the pouring portion 3.

The outer peripheral surface 6 of the wall 5 of the housing 2 is formed substantially smooth. On the other hand, the inner peripheral surface 7 of the wall 5 gently and regularly undulates in the axial direction of the housing 2,
And valleys 7b are formed alternately. Mountain 7a and valley 7
b has a ring shape in the circumferential direction of the housing portion 2, the peaks 7 a and the valleys 7 b have substantially the same shape,
They have the same dimensions. By forming the outer peripheral surface 6 and the inner peripheral surface 7 in such a shape, ring-shaped thick portions 8 and thin portions 9 are alternately formed in the wall portion 5 in the axial direction of the housing portion 2.

The rigidity of the thus constructed bottle container 1 is increased by having the thick portion 8. Also, since the outer peripheral surface 6 of the wall portion 5 is smooth, it is very convenient to print or attach a label to the outer peripheral surface 6.
When the contents are filled in the bottle container 1, the inner peripheral surface 7
Wave shape disappears.

Next, a method of manufacturing the bottle container 1 will be described with reference to FIG.
5 will be described with reference to FIG. The bottle container 1 is manufactured by a blow molding method. First, a preform (preformed product) 10 for the bottle container 1 is formed by, for example, injection molding. As shown in FIG. 2, the preform 10 is provided with a tubular portion 11, a pouring portion 12, and a flange portion 13. The cylindrical portion 11 is a portion which becomes an accommodating portion 2 of the bottle container 1 to be manufactured by being expanded by blowing air, and is formed to have a substantially uniform wall thickness as a whole. In addition, since the well-known technique is used for the injection molding, the description is omitted.

The cylindrical portion 11 of the preform 10 is heated at substantially the same temperature in the circumferential direction so that a high-temperature heating portion and a low-temperature heating portion are alternately generated in the axial direction. This is performed using, for example, a heating device 20 as shown in FIG. The heating device 20 has a high-temperature radiating nozzle 21 and a blowing nozzle 22 facing the cylindrical portion 11 of the preform 10 at right angles.
Are alternately arranged in the axial direction. A heater 23 is accommodated in each of the high-temperature radiation nozzles 21, and a heat ray from the heater 23 heats the cylindrical portion 11 of the preform 10. On the other hand, cooling air is blown out from each blowing nozzle 22 to cool the cylindrical portion 11.

As described above, the preform 10 is rotated about the axis as shown by the arrow while simultaneously performing the heating by the heater 23 and the cooling by the blowing from the blowing nozzle. Then, the cylindrical portion 11 has substantially the same temperature in the circumferential direction, and the ring-shaped high-temperature heating portion and the low-temperature heating portion alternately occur in the axial direction. FIG. 5 is an example of a temperature distribution of the cylinder portion 11 measured along the axial direction. The horizontal axis indicates temperature (° C.), and the vertical axis indicates the position from the flange portion 13. By providing the blower nozzle 22 between two adjacent high-temperature radiation nozzles 21, interference between the heaters 23 can be prevented.

Next, the preform 10 heated with the temperature difference applied to the cylindrical portion 11 is set in the hollow mold 30. The molding surface 31 of the hollow mold 30 is formed in the same shape as the outer peripheral surface 6 of the wall portion 5 of the bottle container 1 to be manufactured, and is formed smoothly.

Next, air is blown into the cylindrical portion 11 of the preform 10 to expand it. Then, as shown in FIG. 4, the outer peripheral surface of the cylindrical portion 11 comes into contact with the forming surface 31 of the hollow mold 30 and is formed into a substantially smooth shape. When the cylindrical portion 11 expands, the high-temperature heating portion is more stretchable than the low-temperature heating portion, so that the high-temperature heating portion is stretched thinner than the low-temperature heating portion, and a mountain portion is formed on the inner peripheral surface of the cylindrical portion 11. 11a and valleys 11b occur. The peak 11a and the valley 11b correspond to the peak 7a and the valley 7b of the bottle container 1, respectively. Therefore, when it is cooled and solidified and taken out of the hollow mold 30, the bottle container 1 is completed.

The height difference and waveform between the peaks 7a and the valleys 7b of the wall 5 in the bottle container 1 are determined by adjusting the temperature of the heater 23, adjusting the temperature and flow rate of the cooling air, and heating the preform 10. It can be set as desired by adjusting the conditions before setting it in the hollow mold 30.

At the time of the preform, thick and thin portions are formed by providing irregularities of peaks and valleys on the outer peripheral surface thereof, and after uniformly heating the preform,
A method of inflating by blowing air is also conceivable. However, in this case, when heating is performed by the heating method used at the time of ordinary blow molding, the ridge near the heater is heated to a higher temperature than the valley far from the heater, and the ridge has better stretchability, so Cannot be obtained with a thick wall distribution. Further, when the preform has such a shape, the structure of the preform molding die becomes complicated, and the cost of the die increases. Therefore, this method was not suitable for producing the bottle container 1.

[0022]

As described above, according to the manufacturing method of the present invention, a thick portion is provided on the wall portion of the storage portion for storing the contents to increase the rigidity of the storage portion and to reduce the outer peripheral surface of the wall portion. In order to provide a bottle container that has been smoothed so that the outer peripheral surface can be printed or the label can be easily attached, the waveform of the inner peripheral surface of the wall of the housing portion can be formed into a desired shape.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a resin bottle container formed by a bottle container manufacturing method according to the present invention.

FIG. 2 is a schematic configuration diagram showing an initial step in a method for manufacturing a bottle container according to the present invention.

FIG. 3 is a schematic configuration diagram showing an intermediate step in the method for producing a bottle container according to the present invention.

FIG. 4 is a schematic configuration diagram showing a final step in the method for manufacturing a bottle container according to the present invention.

FIG. 5 is a diagram showing a temperature distribution of a preformed product in a heated state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin bottle container 2 Housing part 5 Wall part 6 Outer peripheral surface 7 Inner peripheral surface 7a Crest part 7b Valley part 8 Thick part 9 Thin part 10 Preform (preformed product) 20 Heating device 30 Hollow die

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-48-45555 (JP, A) JP-A-63-207630 (JP, A) Real opening Sho-58-82308 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B65D 1/02 B29C 49/64 B65D 1/44

Claims (1)

(57) [Claims] An outer peripheral surface of a wall portion of the accommodating portion is substantially smooth and an inner peripheral surface has a waveform;
A method for manufacturing a resin bottle container in which a thick portion and a thin portion are alternately formed in an axial direction of the housing portion on the wall portion, wherein a cylindrical preform having a substantially uniform thickness is formed. The preformed product is formed and heated so that a high temperature heating portion and a low temperature heating portion are alternately formed in the circumferential direction at substantially the same temperature and alternately in the axial direction. A method for manufacturing a resin bottle container, wherein the resin bottle container is set in a mold and blow-molded.