JP2005074815A - Double wall blow container and its molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for molding a cylindrical double wall blow container in which parison extrusion and blow molding are carried out respectively, continuously and efficiently, an apparatus for the method, and a molding. <P>SOLUTION: In the molding method, an inside parison P1 and an outside parison P2 are extruded from an extrusion die 1, and the outside parison is fusion-bonded to the inside parison at a prescribed position to form seal parts in turn. A parison of double layers forming a hollow chamber in which air of a constant pressure is sealed is molded by the upper and lower seal parts. The molded parison is held by the upper and lower seal parts, a blow molding mold 4 is clamped, and blow air is supplied into the inside parison for blow molding. The molding apparatus, in which two annular orifices 5 and 6 and an air inlet hole 8 formed between the inner and outer orifices are formed, has an extrusion die which suspends a mandrel 7 downward and a seal device 2 having a seal plate 9 collaborating with the mandrel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for molding a cylindrical double-wall blow container, a molding apparatus, and a molded product.

  Synthetic resin material is extruded as two inner and outer parisons, the inner and outer parisons are sandwiched between blow molds, air is blown between the inner and outer parisons, and a cylindrical double-wall blow container Molding is conventionally known. (See Patent Document 1)

Also, during extrusion, the inner parison is a bottomed parison, the outer parison is clamped to the blow mold so as to be sandwiched by the bottom pinch-off part, and air is blown between the inner parison and the inner and outer parisons to form a cylindrical shape. It has been known to form a double wall blow container. (See Patent Document 2)
Japanese Patent Publication No. 44-17279 Japanese Patent Publication No. 44-16795

In each of the conventional molding methods, the inner and outer parisons extruded from the extrusion die are sandwiched between blow molds, and blow air is blown at that position to perform blow molding.
However, when directly blowing a double-wall blow container, the inner parison must be held in place, and if the parison is clamped with a mold and cut, the inner parison will be biased relative to the outer parison. The position of holding the parison between the mold and the blow blowing position could not be separated.
For this reason, the molding time of a single double-wall blow container requires the time for extruding the parison and the time for blow molding, and thus the productivity cannot be increased.

  In the conventional method, the inner volume of the inner container is adjusted by the difference between the air pressure blown into the inner parison and the air pressure blown between the inner and outer parisons. It was not easy to accurately adjust and mold the inner container accurately.

  In the latter case, the inner parison is molded into a bottomed parison and extruded, which complicates the structure and operation of the blow molding device, making the shape of the inner and outer walls always constant and difficult to mold accurately. Met.

  In consideration of the above problems, the present invention extrudes two inner and outer parisons as a parison having a fixed length air chamber sealed on the upper and lower sides, sandwiched between blow molding dies, and blown at a blow molding position. A molding method and molding of a cylindrical double-walled blow container in which parison extrusion and blow molding are carried out efficiently and continuously by blowing a blow-in nozzle and blowing blow air into the inner parison. An object is to provide an apparatus and a molded product.

  In order to achieve the above object, the present invention provides a method for forming a double-wall blow container. From the extrusion die, the inner parison and the outer parison are extruded, and at a predetermined position, the outer parison is fused to the inner parison, and a seal portion is provided. A structure characterized by forming a double-layer parison adapted to form a chamber is adopted.

  As a molding method, the above-described parison is used, the parison is clamped with a blow molding die so as to sandwich the upper and lower seal portions, and blow molding is performed by blowing blow air into the inner parison. Is adopted.

  As a forming device, there were provided two annular orifices, an extrusion die provided with an air blowing hole between two inner and outer orifices, and a mandrel suspended downward, and a sealing device provided with a sealing plate cooperating with the mandrel. The structure characterized by this is adopted.

  The double wall blow container has an inner layer and an outer layer, and adopts a configuration characterized by using a double layer parison that forms an air chamber filled with air of constant pressure between the inner and outer layers. To do.

  In the molding method of the present invention, seal portions are provided on the upper and lower sides of the inner and outer parisons, and the seal portions are sandwiched between molds and clamped, so that the parison can be accurately positioned in the mold. Each wall of the heavy wall is now accurately molded according to the determined shape.

  In addition, since the seal portion is clamped with a mold and clamped, the extrusion, mold clamping position and blowing position can be changed to different positions, and extrusion and blowing can be performed continuously, Productivity was improved.

  The seal portion can be obtained simply by pressing the seal plate against the mandrel at a predetermined position, and the parison can be formed easily and efficiently.

Next, embodiments of the blow molding apparatus and molding method for a double-wall blow container of the present invention and a molded product will be described with reference to the drawings.
First, the outline of the blow molding apparatus will be described. In FIG. 1, 1 is an extrusion die of an extruder, 2 is an inner parison, an outer parison sealing device, 3 is a parison cutter, and 4 is a blow molding die.

The extrusion die 1 is provided with two inner and outer annular orifices 5 and 6, and a mandrel 7 inside the annular orifice 5 extends downward from the lower end of the extrusion die 1.
The mandrel 7 is desirably heated to a predetermined temperature up to its lower end, but cooling of the parison can be prevented by appropriate means such as providing a gap between the inner parison and the mandrel.

  An air blowing hole 8 is provided between the inner and outer annular orifices 5 and 6 so that compressed air is introduced from the outside through an air inlet.

The sealing device 2 is disposed on the left and right with the mandrel 7 interposed therebetween, and includes a sealing plate 9 and a cylinder mechanism 10 that reciprocates the sealing plate 9.
The seal plate 9 presses two inner and outer parisons P extruded from the annular orifices 5 and 6 against the mandrel 7 to seal between the inner and outer parisons P1 and P2.
The cylinder mechanism 10 includes a piston 11 and a plunger 12 having a seal plate 9 attached to the tip thereof, and is actuated by a pressure fluid.

  The blow molding die 4 includes two split dies 13a and 13b, and is formed of a mouth cavity 14, a body cavity 15, and a pinch-off part 16.

  The blow mold 4 is opened from the mold clamping position where the pasolin P extruded below the extrusion die 1 is clamped to the molding position where the blow nozzle is driven into the parison P and blow molded, and the mold is opened. The blow molding machine is a rotary blow molding machine in which a plurality of blow molding dies are arranged to rotate with respect to one extruder.

Next, a method for forming a double wall blow container will be described.
As shown in FIG. 1, the synthetic resin material is extruded as two inner and outer parisons P1 and P2 from the annular orifices 5 and 6 of the extrusion die 1, and as shown in FIG. 2, the lower ends of the inner and outer parisons P1 and P2 are the parison cutters. When the seal plate 9 is lowered to nearly 3, the inner and outer parisons P1 and P2 are pressed against the mandrel 7, and the parisons P1 and P2 are fused to form the seal portion S1.

Next, the seal plate 9 is moved backward, the parisons P1 and P2 are lowered while blowing air from the air blowing holes 8, the parison cutter 3 is operated at a predetermined position, and the excess seal portion S1 is cut off. Next, when the distance h from the lower end of the mouth cavity 14 to the pinch-off portion 16 in the blow molding die 4 is lowered, that is, a distance substantially equal to the height of the barrel of the molded product, as shown in FIG. The plate 9 is actuated to press the parison P, and the inner and outer parisons P1 and P2 are fused to form the seal portion S2.
Thus, the double parison P having the seal portions S1 and S2 on the upper and lower sides and the hollow chamber C in which a predetermined air pressure is sealed between the inner and outer parisons P1 and P2 is obtained.

Next, the seal plate 9 is moved back again, the parison P is lowered, and when the first seal portion S1 is sandwiched by the pinch-off portion 16, the parison P is moved by the blow mold 4 as shown in FIG. While holding, the parison P is cut with the parison cutter 3 and the mold is clamped.
Next, the blow-molded mold 4 that has been clamped is transferred to a blower blowing position.

At the same time, a new blow mold is transferred to the lower side of the extrusion die, and subsequently, the parison P is extruded, the seal portions S1 and S2 are provided on the upper and lower sides, and the double parison P in which the hollow chamber C is formed is formed.
On the other hand, the blow molding die 4 transferred to the blower blowing position is blown by the blow nozzle 17 being blown from above the parison P at the blowing position, and blown with compressed air.

  At the time of blow molding, as shown in FIG. 5, the inner parison P1 is expanded by blowing blow air from the blowing nozzle 17, and the outer parison P2 is also expanded with the air layer of the air chamber C correspondingly, and the outer parison P2 is expanded. Is molded according to the cavity wall surface of the blow mold 4.

In molding, the distance d between the outer parison P2 and the inner parison P1 can be adjusted by the enclosed air pressure and blower blowing pressure.
That is, if the enclosed air pressure is high, the inner and outer wall surfaces can maintain a relatively wide interval, but the interval between the wall surfaces can be narrowed by increasing the blown air pressure because the enclosed air pressure is low.

  Further, the interval position between the upper and lower seal portions S1 and S2 can be set by adjusting the pressing speed of the parison and the operation timing of the seal device.

  Next, the blow molding die 4 is opened, the molded product is taken out and sent to the conveying line, the molded product is cooled, and moldings and burrs are removed to obtain a completed molded product.

Next, the molded double wall blow container will be described.
As shown in FIG. 6, the container 20 includes a mouth portion 21 and a shoulder portion 22, a double-wall body portion 23, and a bottom portion 24, and the mouth portion 21 is formed by a laminated double parison, Screws and neck rings are engraved.

An air chamber 26 is formed in the shoulder portion 22 and the body portion 23 by a double wall including an inner wall 25a and an outer wall 25b.
In the bottom 24, the pinch-off portion 27 is formed of a laminated parison, but the bottom 24 portion following the body portion 23 is a double wall.
The volume of the air in the double wall, that is, the air in the air chamber 26 changes as the blow pressure is removed, the molded product is cooled, etc., but the volume is very small and does not affect the shape of the double wall blow container. .

  The positions, dimensions, and the like of both ends of the air chamber 26 can be changed to desired positions by adjusting the distance between the upper and lower seal portions S1, S2 at the time of molding, but the air chamber 26 having a predetermined length is provided only in the body portion 23. Can also be provided.

The synthetic resin material of the double-wall blow container is not particularly limited as long as it is a resin that can be blow-molded. However, different types of resins may be used as the inner and outer resin materials. You may make it join via.
As the inner and outer resin materials, a resin having gas barrier properties, moisture permeability resistance, light shielding properties, etc. can be selected and used depending on the application.

  In the above molding method and apparatus, the sealing device is operated while continuously extruding the parison. However, when the extrusion speed is high, the sealing device is moved up and down according to the extrusion speed. Also good.

  The double-wall blow container is used as a heat-insulating container because an air chamber is formed, and can accommodate and retain a high-temperature beverage.

  Since the double parison has an air-sealed part and blow-molded, the double-wall blow container can be efficiently molded as in normal direct blow, and it can be used as an insulated container by the air chamber of the molded product. .

It is explanatory drawing of the outline | summary of the blow molding apparatus of this invention. It is a figure explaining the blow molding method of the present invention, and is an explanatory view at the time of lower seal part molding. It is a figure explaining the blow molding method of the present invention, and is an explanatory view at the time of upper seal part molding. It is explanatory drawing at the time of mold clamping. It is explanatory drawing at the time of blow molding. It is a sectional elevational view illustrating a molded double wall container.

Explanation of symbols

C hollow chamber P parison P1 inner parison P2 outer parison S1, 2 seal part 1 extrusion die 2 sealing device 3 parison cutter 4 blow molding die 5, 6 annular Orifice 7 mandrel 8 air blowing hole 9 seal plate 10 cylinder mechanism 11 piston 12 Plunger 13a, b Split mold 14 Mouth cavity 15 Body cavity 16 Pinch-off part 17 Blow nozzle 20 Container 21 Mouth 22 Shoulder part 23 Body part 24 Bottom part 25a Inner wall 25b Outer wall 26 Air chamber 27 Pinch off part

Claims (4)

From the extrusion die, extrude the inner and outer parisons,
At a predetermined position, a double-layer parison is formed by fusing the outer parison to the inner parison, providing a seal portion, and forming a hollow chamber filled with air of a constant pressure by the upper and lower seal portions provided in sequence. A method for forming a double-wall blow container, characterized by forming.   A double wall characterized in that the parison molded by the method according to claim 1 is clamped with a blow molding die so as to sandwich the upper and lower seal portions, and blow blow is blown into the inner parison. Blow container molding method. An air blowing hole is provided between two annular orifices and two inner and outer orifices,
A blow molding apparatus for a double-walled hollow container, comprising: an extrusion die having a mandrel suspended downward; and a sealing device having a sealing plate that cooperates with the mandrel.   A double-wall blow container, characterized in that it has an inner layer and an outer layer, and is formed by using a double-layer parison in which an air chamber in which air of constant pressure is sealed is formed between the inner and outer layers.

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