JPH0767730B2 - Hollow molded product manufacturing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a hollow molded article composed of a plurality of different material parts.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, a main body portion 1 is formed in a three-layer structure in which a foam material 1b having an excellent heat insulating property is sandwiched between inner and outer layers 1a and 1c having high rigidity. In order to integrally form the capping means such as a mountain, the mouth portion 2 which needs to be particularly rigid, when manufacturing a container C or the like made of a highly rigid single material, only the mouth portion 2 is separately molded to form the main body 1. It is usually secondary to adhere to. However, the secondary fixing method is required not only to spend more manufacturing steps but also to secure the necessary fixing strength.

Further, particularly in the production of resin molded products whose material costs are relatively high, reuse of the loss portion generated in the molding process is an important issue, but as shown in FIG. Many kinds of materials are mixed in the loss generated in the molding of the three-layer structure product, and the reuse thereof is not easy.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is easy to integrally form each part of a hollow molded product with a material configuration according to the application and to produce a loss material that is generated. It is an object of the present invention to provide an apparatus for manufacturing a hollow molded article having a composite material suitable for reuse.

[0005]

EXAMPLES The constitution of the present invention will be specifically described below based on examples. First, one embodiment of a manufacturing apparatus in which the method of the present invention is carried out will be described based on the schematic view of FIG. In addition, in the manufacturing apparatus of this example, as shown in FIG. 3A, the bellows portion P ₂ is formed of, for example, low density polyethylene (LD-PE).
Such as a pipe P in which the other part P _{10 ′} P ₁₁ is formed of a hard material such as high-density polyethylene (HD-PE) to improve the stretchability of the bellows part, or the like, as shown in FIG. 3B. joint J that as the engaging portion J ₂ and the other portion J ₁ is formed of a soft material to improve the compatibility fitting formed of a hard material shown in, or 3
As shown in (c), a bent product V ₂ is made of a soft material and a joint V ₁ is made of a hard material. This is a device intended to be manufactured.

In FIG. 2, there are provided two first and second parison extruders 3 and 4 each having a screw 5 disposed in each of the flow passages 3a and 4a formed inside thereof. ,
Each tip is connected to a common nozzle 6. Therefore, the thermoplastic resin material supplied from each hopper (not shown) is heated and melted, and is made to flow in each flow path toward the nozzle 6 as the screw 5 rotates. The nozzle 6 is arranged so as to pour out the sent resin material vertically downward. A mandrel 6a having a tapered lower end is vertically arranged at a substantially central portion of the nozzle 6.
This central portion, ventilation holes 6a ₁ is drilled which is connected to a pressurized gas supply source, such as a compressor 6a _2. Around the mandrel 6a, the first flow path 7 is provided with the mandrel 6a.
Is formed along the axial direction of. Further, a second flow path 8 partitioned from the first flow path 7 by the inner pipe member 6b is formed outside the first flow path 7, and the second flow path 8 has a flow direction in the mandrel 6a. A flow region is formed by the outer pipe member 6c so as to extend along the axial direction of. The lower ends of the first flow path 7 and the second flow path 8 merge near the lower end surface of the nozzle 6 to form a parison spout 6d. on the other hand,
The upper portions of the first and second flow passages 7 and 8 are bent in the lateral direction of the nozzle 6, and the first flow passage 7 is the flow passage 3a of the first extruder 3.
The second flow path 8 is communicated with the flow path 4a of the second extruder 4, respectively. A mold set (not shown) for accommodating the poured parison and performing blow molding is arranged immediately below the nozzle 6.

Thus, for example, as in this example, the extruders 3, 4 are
Shut-off valves 9 and 10 capable of appropriately shutting off the flow paths 3a and 4a are provided at a connecting portion between the nozzle 6 and the nozzle 6. The shut-off valves 9 and 10 are control means 11 respectively.
And opens and closes each flow path 3a, 4a in accordance with an instruction from the control means 11. Therefore, by using, for example, a microcomputer as the control means 11, a suitable operation pattern corresponding to the material composition of the product to be molded is stored as a program, and each shut-off valve is opened / closed in accordance with the program to obtain the desired material. A parison is formed by pouring in the composition. In this case, the operations of the shut-off valves 9 and 10 and the extruders 3 and 4 are appropriately interlocked with each other to form the flow paths 3a and 4a.
It is necessary to prevent the internal pressure from rising abnormally. In addition, the detection means PD such as a photoelectric tube captures the light beam from the light source LS whose length of the parison to be poured out is arranged in the vicinity of the area directly below the nozzle 6, and the control means 11 responds to the signal sent from this detection means. Alternatively, the operation of the shutoff valves 9 and 10 may be controlled.

Next, one embodiment of the method of the present invention will be described based on the operation of the above-mentioned manufacturing apparatus. By the way, when manufacturing the pipe P having the bellows portion P ₂ shown in FIG. 3A, as the raw material, for example, LD-PE is used as the soft resin for the bellows portion P ₂ , and the other portion P _{10 ′} is used as described above. P
For example, HD-PE may be used as the hard resin for ₁₁ , but other combinations such as hard vinyl chloride and soft vinyl chloride may be used. A soft resin and a hard resin, which are easily melted with each other, preferably have a combination of materials of the same system such as this example from the viewpoint of strength of the boundary portion, but interposing an adhesive or the like even in a combination of materials having poor affinity. It is possible to apply by. Now, the second extruder is equipped with HD-PE on the first extruder 3.
An extruder is selected to supply LD-PE to the extruder 4.
Then, HD-PE is caused to flow in the flow path from the flow path 3a through the shutoff valve 9 and the first flow path 7 to the spout 6d, and the shutoff valve 10 from the other flow path 4a.
The flow path through the second flow path 8 to the spout 6d through
Let D-PE flow through.

First, in order to pour out the parison p ₁₀ corresponding to the portion P ₁₀ made of HD-PE of the product pipe P, the valve 9 is opened to operate the first extruder 3 and the valve 10 is closed. Then, the second extruder 4 is stopped. When the parison p ₁₀ is poured out by the length l ₁₀ corresponding to the length L ₁₀ portion of the P ₁₀ portion of the product P, the control means 11 equipped with a microcomputer closes the valve 9 according to a predetermined program to make the first. The extruder 3 is stopped and the valve 1
0 is opened to operate the second extruder 4. As a result, the material of the parison p to be poured out is switched to LD-PE corresponding to the bellows portion P ₂ of the pipe P. In this case, since the shutoff valves 9 and 10 are separated from the spout 6d,
Following the opening / closing operation of the shut-off valves 9 and 10, the material that is immediately poured out is gradually changed without being changed. Therefore, as shown in the drawing, the boundary surface is formed obliquely with respect to the pouring direction, but this is practically inconvenient and, on the contrary, contributes to increasing the strength of the boundary portion where the mechanical strength decreases. To do. When the parison p ₂ portion made of LD-PE is poured out by the length l ₂ corresponding to the length L ₂ of the bellows portion P ₂ , similarly, the control means 11 causes the first parison p _{10 to start.}
The operating state of each valve and each extruder is switched to the original state of pouring out, and the parison made of HD-PE corresponding to the P ₁₁ portion of the pipe P is poured out. After the parison p having a material structure corresponding to the material structure of the pipe P formed as described above is housed in a mold (not shown) arranged immediately below and clamped, the parison p is pressed from, for example, the ventilation hole 6a _1. By blowing pressurized gas and blow molding, it is possible to obtain a pipe P having a bellows portion P ₂ that is highly stretchable as shown in FIG.
Of course, any other known method can be used as the blowing method.

In the above embodiment, the shutoff valves 9 and 10 and the operations of the first and second extruders 3 and 4 are interlocked to switch the pouring material of the parison. For products whose boundary can be expected to be relatively long, the shutoff valves 9 and 10 are omitted and only the first and second extruders 3 and 4 are driven and controlled by the control means 11 to obtain a parison having a desired material structure. It is also possible.

Next, another embodiment of the device of the present invention will be described with reference to the schematic view of FIG. In the following embodiments, the same components as those in the above embodiment are designated by the same reference numerals and the description thereof will be omitted. In this example, the two systems of passages for passing two kinds of materials are opened and closed by moving the mandrel 12 in the longitudinal axis direction without using the shutoff valve. That is, as shown in FIG. 4, the upper portion of the mandrel 12 that is inserted and supported in the nozzle 6 so as to be movable in the longitudinal axis direction is connected to the driving means 13 such as a hydraulic device. This drive means 1
3 is likewise connected to the control means 11.

Thus, at the lower end portion of the mandrel 12 near the spout 6d, the projection or the engaging portion 1 is provided over the entire peripheral surface thereof.
4 are formed. Further, at the lower end portion of the inner surface 6b ₁ of the inner pipe portion 6b facing the peripheral surface of the mandrel 12, a projection or an engagement portion 15 is projected at a position slightly above the projection or the engagement portion 14. It is formed along the inner peripheral surface of the part or the engaging part 14 so as to be engageable. Therefore, by moving the mandrel in the vertical direction, the first flow path 7 is opened and closed, and the flow rate of the material flowing therethrough can be adjusted.

When manufacturing the hollow molded product having the structure shown in FIGS. 3A to 3C by the apparatus of this embodiment, the mandrel 12 is lowered to open the first flow path 7 and the second extrusion. It suffices to stop the machine 4 and switch the material. Further, in order to more freely switch the two types of pouring materials, the shut-off valve 10 may be provided only in the flow path 4a of the second extruder 4. Further, the nozzle 6 is configured so that the inner pipe portion 6b is movable in the vertical direction.
As shown in FIG. 3, protrusions 16 and 17 are formed on the outer peripheral surface of the inner pipe portion 6b forming the second flow path 8 and the inner peripheral surface of the outer pipe portion 6c so that the inner pipe portion 6b can be engaged with the inner pipe portion 6b. You may.
In this case, the material to be extracted can be sharply switched by moving the inner pipe portion 6b up and down.

[0014]

As described in detail above, according to the present invention, the pouring of plural kinds of materials is controlled in accordance with the material composition of the product to be molded to form the parison, so that the composite according to the application can be obtained. It becomes possible to easily form a hollow molded product including a material.
Further, since the material pouring can be controlled so that the loss material generated each time a hollow molded article made of a plurality of materials is molded becomes a single material, the recycling rate of the loss material can be significantly improved. Therefore, it becomes possible to inexpensively manufacture a high-quality hollow molded product having a composite material suitable for the purpose. It should be noted that the present invention should not be limited to the embodiments having the above characteristics, and various modifications can be made within the technical scope of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a container C having a three-layer structure.

FIG. 2 is a schematic diagram showing an embodiment of the present invention.

FIG. 3 is an explanatory view showing hollow moldings (a) to (c) each of which has two kinds of materials formed according to the present invention.

FIG. 4 is a schematic view showing another embodiment of the present invention.

5 is an explanatory view showing a modification of the embodiment shown in FIG.

[Explanation of symbols]

 3 1st extruder 4 2nd extruder 6 Nozzle 7,18 1st flow path 8,19 2nd flow path 9,10 Shut-off valve 11 Control means 14-17 Engagement protrusion 20 3rd flow path

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29C 49/78 7619-4F // B29L 9:00 22:00

Claims (2)

[Claims] 1. At least two supply paths for melting raw materials and feeding them to a spout, supply port closing means for selectively closing the supply path in the vicinity of the spout, and a parison poured out from the spout. A blow molding means for accommodating the same in a molding die and performing blow molding into a desired shape. The supply port closing means projects in opposite directions from wall surfaces facing each other in the supply path, and relatively approaches and separates. An apparatus for manufacturing a hollow molded article, comprising at least a pair of protrusions freely provided, and controlling the opening and closing of the supply path by moving the pair of protrusions in and out of contact with each other. 2. At least two supply passages for melting the raw material and delivering it to the pouring outlet, a supply means for supplying the raw material to each of the supply passages, a shut-off valve provided in each of the supply passages,
Control means operatively coupled to the shut-off valve and the supply means for controlling the operation of the shut-off valve and the supply means so as to switch the raw materials from the respective supply paths in the vicinity of the spout. An apparatus for manufacturing a hollow molded article, comprising: blow molding means for accommodating a parison poured from a pouring outlet in a molding die and blow molding the parison into a desired shape.