JP4164345B2 - Blow molding split mold for containers - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a split mold for forming containers such as bottles and cans, and more particularly to a blow mold split mold for containers.
[0002]
[Prior art]
Conventionally, a resin container such as a bottle has a shape of an inner surface of a mold by blowing a gas into the rough shape of the container from its opening, expanding the rough shape of the container and pressing it against the inner surface of the mold. It is formed by a blow molding method in which a container is formed by applying. In this example of blow molding, generally, an injection molding process for producing a cylindrical preform (preliminary body called a parison) by extruding a molten resin from a blow nozzle (filling table) is obtained by this injection molding process. Blow molding that keeps the mouth part of the preform in an unstretched state and blows it into the inside of the blow mold split mold for containers by blowing and expanding a pressurized gas such as air or nitrogen. When performing the process and releasing the obtained product, the blow mold is divided from the center to the left and right.
[0003]
[Problems to be solved by the invention]
However, when manufacturing various types of containers using conventional molds for forming containers, it has been necessary to prepare a variety of types corresponding to the molds. That is, as the mold, it is common to use a split mold that is divided by a plane passing through the central axis. The split mold is configured to mold the left and right halves of the container to be obtained, for example. Therefore, one specific type of container is formed by the left and right split molds. Therefore, when manufacturing many kinds of containers, it is necessary to prepare many kinds of molds according to the kinds of containers to be obtained. As a result, there is a disadvantage that the mold cost is increased.
[0004]
The present invention has been made against the background of the above circumstances, and provides a blow molding split mold for containers that can mold several types of containers with a single mold facility and can greatly reduce mold costs. It is intended to do.
[0005]
[Means for Solving the Problem and Action]
In order to achieve the above object, the invention described in claim 1 is characterized in that gas is blown into the rough shape material for the container from the opening thereof to expand the rough shape material for the container and press it against the inner surface of the mold. In the blow molding split mold for a container that forms the container by giving the inner surface shape of the mold, a plurality of molds for molding the body that are divided by a plane passing through the central axis of the container and mold the body of the container And a holder for detachably holding these barrel forming molds and opening and closing these barrel molding dies, and molding a top or bottom adjacent to the barrel in the axial direction, and e Bei an end mold to be joined in close contact with the end portion of the barrel portion-molding mold are moved in the axial direction, said plurality of body part mold is rough shape for the container It has an open end that hooks the mouth of the material, and before it is hooked on the open end A blow nozzle which is fitted in close contact with the mouth of the container for rough profile, is characterized in that it is configured so as to pass through the stretching cable extending down the said container for rough profile in the axial direction.
[0006]
Therefore, according to the first aspect of the present invention, the barrel portion of the container can be formed by being divided in a plane passing through the central axis of the container by the plurality of body portion molding dies. The holder can detachably hold the barrel forming mold and can open and close the barrel forming mold. The top or bottom adjacent in the axial direction to the barrel is molded by the end molding die and moved in the axial direction so as to be in close contact with the end of the barrel molding die. Can be made.
[0007]
Further, the invention of claim 2 is such that the portion in the vicinity of the joint portion between the body portion forming die and the end portion forming die forms a straight portion with respect to the axial direction of the container. It can be characterized by being.
[0008]
Therefore, in the invention of claim 2, a linear portion with respect to the axial direction in the container is formed by the shape of the portion in the vicinity of the joint portion between the body portion forming die and the end portion forming die. be able to.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a split mold for forming a container in which a molded product of a plastic bottle of the present invention is formed will be described below with reference to the drawings. In this embodiment, PET (polyethylene terephthalate) resin is used as the material of the bottle, but other plastic materials such as polyethylene naphthalate, polypropylene, polyethylene, polycarbonate, nylon and the like can be used.
[0010]
FIG. 1 shows an arrangement state of an embodiment of the present invention. By a blow molding split mold 1 used for molding a container by a blow molding facility as a target here, a preform 2 and A barrel mold 4 that determines various shapes of the PET bottle 3, a holder 5 that holds the outer periphery of the barrel mold 4, and the inside of the holder 5 moves in the blow-injecting direction, and the plastic bottle A bottom mold 6 is formed that forms the shape of the lower part.
[0011]
As shown in FIG. 2, the holder 5 includes an L-side holder 5 ′ and an R-side holder 5 ″. The L-side holder 5 ′ and the R-side holder 5 ″ are fastened with bolts (not shown). It has come to be. The holder 5 holds the body mold 4 and the bottom mold 6 so as to cover the outer peripheral side surface. Further, as shown in FIG. 1, the body part mold 4 and the bottom part mold 6 are formed in a cylindrical shape by the holder 5. Further, the body part mold 4 is fastened with a bolt (not shown) or the like by the holder 5.
[0012]
The holder 5 can attach and detach a plurality of types of body molds 4 formed at the mouth side from the bottom with bolts (not shown) and the like, and the bottom mold 6 is slid accordingly. Positioning.
[0013]
Moreover, steel (SK material etc.), aluminum (A5052, A6061, A7075 etc.), beryllium copper (C1720W etc.) can be used for the main material used for blow molding like the said holder 5. FIG.
[0014]
The length of the filling direction of the PET bottle 3 can be determined freely by exchanging the body part mold 4. The body mold 4 is used to fix the preform 2 supplied downward from a stretch cable 7 provided thereabove via a blow nozzle 8. Furthermore, a three-dimensional curved surface shape corresponding to the molded product is formed inside the body mold 4 in a state where the mold is clamped.
[0015]
The bottom mold 6 is floated on a forming mold 9 that forms the bottom shape of the container, a free piston part 10 that can stroke the bottom mold 6 itself, and a wall surface around the free piston part 10. The piston ring 11 is provided.
[0016]
The forming mold 9 is in contact with the lower part of the body mold 4 shown in FIG. 1 and is provided inside the holder 5. A predetermined slide mechanism 12 such as an air cylinder (not shown) is attached to these bottom molds 6 and is set to slide in the opposite filling direction by air pressure or hydraulic pressure.
[0017]
The body mold 2 conforming to the target volume of the PET bottle 3 is formed on the holder 5 by the bottom mold 6. Further, when the slide mechanism 12 is operated, the bottom mold 6 is in close contact with the bottom of the body mold 4. Also, a closed space 13 is provided between the body mold 4 and the bottom mold 6. Further, when the preform 2 is blow-molded, an exhaust passage 14 is provided as a passage for air from the closed space 13.
[0018]
A piston ring 11 is floated between the free piston portion 10 and the forming die 9 by the bottom die 6.
[0019]
The piston ring 11 comes into contact with the inner wall of the body mold 4. Further, the piston ring 11 allows the bottom mold 6 to be disposed on the wall inside the body mold 4 while maintaining a certain distance.
[0020]
The pin 15 provided on the upper portion of the free piston portion 10 is press-fitted into the central hole 16 below the forming die 9 by the free piston portion 10. Further, the free piston portion 10 and the forming die 9 are coupled.
[0021]
In addition, the preform 2 is continuously brought into contact with the closed space 13. The designs and patterns of the mold design surfaces 17 and 18 of the body mold 4 and the bottom mold 6 are transferred to the preform 2.
[0022]
Next, a blow molding process of a bottle (container) using the above-described split mold 1 for blow molding will be described. In the example described below, it is assumed that the preform 2 is molded in a separate process in advance.
[0023]
First, the barrel die 4 corresponding to a target volume bottle is attached to the holder 5, and the barrel die 4 is closed together with the holder 5, and the bottom die 6 is raised from below, The body part 4 is brought into close contact with the bottom part. By doing so, a cavity (space 13) corresponding to the shape of the bottle to be obtained is formed.
[0024]
The preform 2 prepared in advance is inserted into the upper opening end of the space 13. In that case, the mouth portion of the preform 2 is hooked on the opening end of the mold and protrudes upward. The blow nozzle 8 is fitted into the mouth portion in close contact, and the stretch cable 7 is inserted through the blow nozzle 8. While the preform 2 is pushed and extended in the axial direction by the stretch cable 7, a pressurized gas such as air or nitrogen is blown into the preform 2. As a result, the preform 2 expands in the axial direction and the radial direction and is finally pressed against the inner surfaces of the body mold 4 and the bottom mold 6 to form the inner surface shape of these molds, that is, the mold design molding surface 17. 18 is formed into a shape along the line 18.
[0025]
Then, a cooling process is performed. In that case, the molded product is solidified and adjusted to the shape of the bottle. In this cooling step, for example, a temperature control medium (not shown) provided in the body mold 4 and the bottom mold 6 is switched to a low temperature. The body mold 4 and the bottom mold 6 may be cooled rapidly or forcibly cooled from the inside of the molded product using an air chiller or the like (not shown).
[0026]
In parallel with this cooling process or after the cooling process, the above-described stretch cable 7 is raised and pulled out from the molded product, and the blow nozzle 8 is removed from the mouth of the molded product. Next, the bottom mold 6 is processed and separated from the body mold 4. In this state, the molded body, that is, the pet bolt 3 is taken out by dividing the barrel mold 4 having the divided structure into the left and right sides together with the L-side holder 5 ′ and the R-side holder 5 ″.
[0027]
When a container of a different type from the container is manufactured after the blow molding, the bolt (not shown) holding the L-side holder 5 ′ and the R-side holder 5 ″ is loosened to loosen the L-side holder. Open 5 'and R side holder 5 ". The bolts (not shown) for fastening the L-side holder 5 ′ and the R-side holder 5 ″ and the body die 4 are loosened. Then, the body die 4 is removed from the L-side holder 5 ′ and the R-side holder 5 ″. Remove. Next, in order to mount the body mold 4 of a different type, the body mold 4 is placed in the L side holder 5 ′ and the R side holder 5 ″ and fixed with bolts (not shown). The L side holder 5 ′. And close the R side holder 5 ″. Then, a bolt (not shown) for fixing the L-side holder 5 ′ and the R-side holder 5 ″ is fastened and replaced with the body mold 4.
[0028]
In addition, the air existing in the enclosed and enclosed space 13 is discharged to the outside of the blow-molded split mold 1 through the exhaust passage 14 by the body part mold 4, and the inside and outside of the preform 2. The pressure difference may be increased. In this case, the preform 2 can be reliably brought into contact with the mold design surfaces 17 and 18 without increasing the amount of air in the preform 2 so much.
[0029]
In addition, “rough shape material for containers” described in claims is read as “preform”, “containers” is read as “pet bottles”, and “molding die” is called “body die” "End mold" can be read as "bottom mold".
[0030]
【The invention's effect】
As described above, according to the first aspect, the body part of the container can be formed by being divided by a plurality of body part forming dies on a plane passing through the central axis of the container. The holder can detachably hold the barrel forming mold and can open and close the barrel forming mold. The top or bottom adjacent in the axial direction to the barrel is molded by the end molding die and moved in the axial direction so as to be in close contact with the end of the barrel molding die. Can be made. As a result, several types of containers can be formed by one mold facility. Furthermore, it is possible to greatly reduce the mold cost for mold replacement.
[0031]
Moreover, according to invention of Claim 2, a linear part with respect to the axial direction in the said container is formed by the shape of the part vicinity of the junction part of the said body part shaping | molding die and the said edge part shaping | molding die. Can be formed. As a result, it is possible to form a parting line of a mold on an inconspicuous design surface.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram for explaining a divided mold for container blow molding according to an embodiment of the present invention.
FIG. 2 is a schematic perspective view for explaining a main mounting configuration of a split mold for container blow molding according to an embodiment of the present invention.
FIG. 3 is a schematic process diagram for explaining the process by the container blow molding split mold according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Blow molding division mold, 2 ... Preform, 3 ... PET bottle, 4 ... Body mold, 5 ... Holder, 5 '... L side holder, 5 "... R side holder, 6 ... Bottom mold

Claims (2)

Blow molding for containers in which gas is blown into the rough shape material for containers to expand the rough shape material for containers and press it against the inner surface of the mold to give the inner surface shape of the mold and mold the container In the split type,
A plurality of barrel forming molds that are divided by a plane passing through the central axis of the container and mold the barrel of the container;
A holder for detachably holding these barrel molding dies and opening and closing these barrel molding dies;
An end molding die that molds a top portion or a bottom portion adjacent to the barrel portion in the axial direction, and is moved in the axial direction so as to be in close contact with an end portion of the barrel molding die; Bei to give a,
The plurality of barrel forming molds have an opening end for hooking the mouth portion of the container rough shape member, and a blow nozzle closely fitted to the mouth portion of the container rough shape member hooked on the opening end. Further, the container blow-molded split mold is configured so as to be inserted through a stretch cable that extends and extends the container rough shape member in the axial direction .   The portion in the vicinity of the joint portion between the body portion molding die and the end portion molding die is shaped to form a straight portion with respect to the axial direction of the container. Item 2. The blow molding split mold for containers according to Item 1.

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