JPH0615168B2 - Compound parison forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite parison forming device comprising a plurality of different material parts.

Conventionally, as shown in FIG. 1, the main body portion 1 is formed in a three-layer structure in which a foam material 1b having excellent heat insulating property is sandwiched between the inner and outer layers 1a and 1c having high rigidity, and the main body portion 1 has a screw thread or the like. In the case of manufacturing a container C or the like made of a single material having a high rigidity, the mouth portion 2 which requires a high rigidity in order to integrally form the capping means,
Usually, only the mouth portion 2 is separately molded and secondarily fixed to the main body 1. However, the method of secondarily fixing requires not only more man-hours for manufacturing but also securing necessary fixing strength.

Also, in the manufacture of resin molded products, in which the material cost is relatively expensive, the reuse of the loss portion generated in the molding process is an important issue, but the three layers as shown in FIG. Many kinds of materials are mixed in the loss generated in the molding of structural products, and it is not easy to reuse them.

The present invention has been made in view of the above points, and a composite material suitable for reusing the loss material that can be easily integrally molded with a material configuration corresponding to each part of the hollow molded article and is generated. It is an object of the present invention to provide a composite parison forming device which forms a composite parison suitable for use in the manufacture of a hollow molded article provided with the composite parison.

Hereinafter, the configuration of the present invention will be described based on specific examples. First, a manufacturing apparatus 1 in which the method of the present invention is implemented
An example will be described based on the schematic diagram of FIG.
In the manufacturing apparatus of this example, as shown in FIG. 3 (a), the bellows portion P ₂ is formed of a soft material such as low density polyethylene (LD-PE), and the other portions P ₁₀ and P ₁₁ are formed of high density. A pipe P made of a hard material such as polyethylene (HD-PE) to improve the stretchability of the bellows part, or a fitting part J ₂ made of a soft material and the other part J as shown in FIG. 3 (b). ₁ is made of a hard material to improve the fitting property, or as shown in FIG. 3 (c), the bent portion V ₂ is made of a soft material and the joint portion V ₁ is made of a hard material. This is an apparatus for producing hollow products having two kinds of material configurations, such as the elbow V which has improved compatibility.

In FIG. 2, the flow paths 3a and 4 formed inside each of them.
Two first and second parison extruders 3 and 4 each having a screw 5 disposed in a are provided, and their respective tips are 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, and a ventilation hole 6a connected to a pressurized gas supply source such as a compressor 6a ₂ is provided at a central portion of the mandrel 6a. ₁ is drilled. This mandrel 6
Around the a, a first flow path 7 is formed along the axial direction of the mandrel 6a. Further, on the outer side of the first flow path 7, there is provided a second pipe partitioned from the first flow path 7 by the inner pipe member 6b.
The flow passage 8 is formed, and the second flow passage 8 has a flow passage region formed by the outer pipe member 6c such that the flow passage direction is along the axial direction of the mandrel 6a. 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 first and second
The upper part of each flow path 7, 8 is bent in the lateral direction of the nozzle 6, the first flow path 7 is the flow path 3a of the first extruder 3, and the second flow path 8 is the flow path of the second extruder 4. 4a, 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, shut-off valves 9 and 10 capable of appropriately shutting off the flow paths 3a and 4a are provided at the connecting portions between the extruders 3 and 4 and the nozzle 6 as in this example. The shut-off valves 9 and 10 are connected to the control means 11, respectively, and open and close the flow paths 3a and 4a in response to an instruction from the control means 11. Therefore, by using, for example, a microcomputer or the like as the control means 11, a suitable operation pattern corresponding to the material configuration of the product to be molded is stored as a program, and each shutoff valve is opened / closed in accordance with the program.
The parison is cast with the desired material composition. In this case, each shutoff valve 9, 10 and each extruder 3, 4
It is necessary to appropriately interlock the operation of the above so that the pressure in each of the flow paths 3a and 4a does not rise 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 manufacturing apparatus described above. By the way, when the pipe P having the bellows portion P ₂ shown in FIG. 3 (a) is manufactured,
As a raw material, for example, LD-PE may be used as the soft resin for the bellows portion P ₂ as described above, and HD-PE may be used as the hard resin for the other portions P ₁₀ and P ₁₁ . A combination of 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, HD-PE is fed to the first extruder 3 and L is fed to the second extruder 4.
The extruder is selected to feed D-PE. Then, HD-PE is caused to flow in the flow path from the flow path 3a to the spout 6d through the first flow path 7 via the shutoff valve 9, and from the other flow path 4a via the shutoff valve 10. Second
LD-PE is allowed to flow through the flow path 8 to the spout 6d.

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 to the second position. The extruder 4 is stopped. Once the parison p ₁₀ is dispensed by a length l ₁₀ corresponding to the length L ₁₀ parts of P ₁₀ portion of the product P, the the control means 11 which includes a microcomputer closes the Parubu 9 based on a predetermined program 1 The extruder 3 is stopped, the valve 10 is opened, and the second extruder 4 is operated. As a result, the material of the parison p that is 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, the material to be spouted is immediately switched without changing the material following the opening / closing operation of the shutoff valves 9 and 10. Therefore, as shown in the figure, the boundary surface is formed obliquely with respect to the pouring direction, but this is practically inconvenient and rather 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 , the control means 11 similarly
Switching the operating state of each valve the extruder first parison p ₁₀ to the original state that issued Note, for pouring a parison made of HD-PE corresponding to P ₁₁ portion of the pipe P. The parison p having a material constitution corresponding to that of the pipe P thus formed is housed in a die (not shown) arranged directly below and clamped, and then pressure is applied from the ventilation hole 6a _1. If gas is blown and blow-molded, a pipe P having a bellows portion P ₂ with high elasticity as shown in FIG. 3 (a) can be obtained.

In the above embodiment, the shutoff valves 9 and 1 are
0 and the operation of the first and second extruders 3 and 4 were interlocked to switch the pouring material of the parison. However, for products in which the boundary of the material can be expected to be relatively long, the shutoff valve 9, It is also possible to omit 10 and drive and control only the first and second extruders 3 and 4 by the control means 11 to obtain a parison having a desired material configuration.

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 vertical direction without using a shutoff valve. That is, as shown in FIG.
A mandrel 1 which is inserted and supported so as to be vertically movable inside.
The upper part of the projection 2 is connected to a driving means 13 such as a hydraulic device. This drive means 13 is likewise connected to the control means 11.

Thus, at the lower end of the mandrel 12 close to the spout 6d, a projection 14 is formed over the entire peripheral surface thereof. or,
At the lower end of the inner surface 6b ₁ of the inner pipe portion 6b facing the peripheral surface of the mandrel 12, the protrusion 15 is engageable with the protrusion 14 at a position slightly above the protrusion 14 It is formed along the surface. 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.

The manufacturing apparatus of this example is convenient for manufacturing a hollow product partially having a two-layer structure. That is, as shown in FIG. 5, when the parison p ′ partially formed in a two-layer structure is poured out, the mandrel 12 is raised to engage the protrusions 14 and 15 to close the first flow path 7. out NOTE beginning of the single layer portion p _'1 in the state, the first flow path 7 is lowered to the after mandrel 12
'If you close the first flow path to raise the mandrel 12 again later with ₂ predetermined length Note out, the desired parison p' 2 layer portion p Open is formed. In this case, since the positions of the protrusions 14 and 15 that open and close the first flow path 7 are close to the spout 6d,
Controlled flow is very good response of the material flowing through the flow channel 7 can be kept to the minimum necessary two layer portion p _'2 and single-layered portion p' ₁ of the length of the boundary. Therefore, the single layer part p ′ ₁
If a hollow molded article having a two-layer structure is blow-molded in consideration of the loss portion, the loss portion becomes a substantially single material, and the recovery rate of the loss material can be significantly increased.

When manufacturing the hollow molded product having the configuration shown in FIGS. 3 (a) to 3 (c) with the apparatus of this example, the mandrel 12 is lowered to open the first flow path 7 and It suffices to stop the extruder 4 and switch the material. 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 constructed so that the inner pipe portion 6b is movable in the vertical direction, and as shown in FIG. 6, the outer peripheral surface of the inner pipe portion 6b and the outer pipe portion 6c forming the second flow passage 8 are formed. The protrusions 16 and 17 may be formed so as to be engaged with each other by raising the inner pipe portion 6b on the inner peripheral surface. In this case, the material to be poured out can be sharply switched by moving the inner pipe portion 6b up and down.

Next, still another embodiment of the present invention will be described based on the schematic view of FIG. As shown in FIG. 1, the manufacturing apparatus of this example is suitable for manufacturing a hollow molded product in which a sandwich type three-layer structure portion is formed which is made of two kinds of materials and one material is sandwiched by the other material. It is a device. In this case, an example of a preferable combination of materials having affinity with each other will be shown below.
It looks like the table.

In addition to these, combinations of resin materials with poor affinity are also available.
It can be applied by interposing an appropriate adhesive as in the above-mentioned embodiment.

In addition to the combinations shown in Table 1 above, combinations of resin materials as shown in Table 2 below are also possible.

As shown in FIG. 7, the parison pouring nozzle 6 of this example has three first, second, and third flow paths 18, 19, and 20. Second channel 1 for pouring out the intermediate layer material
Only 9 is communicated with the first extruder 3, and the first and third flow paths 18, 20 for pouring the inner and outer layer materials are both communicated with the second extruder 4. The flow paths 3a and 4a of each extruder
A shut-off valve 9.10, which is connected to the control means 11 as in the embodiment shown in FIG.

Therefore, the body portion 1 of the three-layer structure of the container C shown in FIG.
For the time to pour the parison equivalent to, open both valves 9 and 10 to pour the three-layer parison, and open the mouth part 2
For the time to pour the parison corresponding to the above, if the valve 9 is closed to stop the pour-out of the intermediate layer material and the parison consisting only of the inner and outer layer materials is continuously poured out, the material composition of the container C is adapted. The parison of the material constitution can be easily obtained. Further, in this case, since the loss portion between the formed parison is almost generated as a single resin material of the inner and outer layer materials, the recycling can be efficiently and easily performed.

Also in this embodiment, the nozzle 6 is formed so that the inner pipe portion 6b can move in the vertical direction, and the opening and closing of the second flow path is performed by a pair of engaging projections provided near the spout 6d. With this structure, the switching between the three-layer portion and the single-layer portion of the parison is performed more sharply, and the recycling rate of the loss material is further improved. Alternatively, three extruders may be provided, and the first flow passage 18 and the third flow passage 19 may be connected to separate extruders via individual shut-off valves. As a result, for example, the inner layer is LD
A hollow molded article having a three-layer structure of three kinds of materials including PE, an intermediate layer of EVA (ethylene vinyl acetate), and an outer layer of HD-PE can be easily molded.

As described above in detail, according to the present invention, by controlling the pouring of plural kinds of materials according to the material composition of the product to be molded to form a parison, a hollow material having a composite material according to the application can be obtained. The molded product can be easily molded. 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 is not limited to the above-mentioned specific embodiments, and it goes without saying that various modifications can be made within the technical scope of the present invention. For example,
By appropriately combining the number of flow paths formed in the extruder and nozzle, hollow molded products with higher composite materials such as hollow molded products having a five-layer structure made of three types of materials can be easily manufactured. It becomes possible to manufacture.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a container C having a three-layer structure, FIG. 2 is a schematic view showing one embodiment of the present invention, and FIG.
FIGS. 3 (a) to 3 (c) are explanatory views showing hollow molded products each containing two kinds of materials, and FIG. 4 is a schematic view showing another embodiment of the present invention, and FIG. Is a parison for two-layer structures
FIG. 6 is an explanatory view showing p ', FIG. 6 is an explanatory view showing a modified example of the embodiment shown in FIG. 4, and FIG. 7 is a schematic view showing still another embodiment of the present invention. (Explanation of reference numerals) 3: First extruder 4: Second extruder 6: Nozzle 7,18: First flow path 8,19: Second flow path 9,10: Shut-off valve 11: Control means 14,15 , 16,17: Engagement protrusion 20: Third flow path

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B29C 49/78 6122-4F // B29L 22:00 4F

Claims (5)

[Claims] 1. A two supply path for melting a raw material and feeding it to a spout through a confluence near the spout, and one of the two supply paths is selectively opened and closed at the confluence. And a pair of projections that project inwardly of the supply path in opposite directions and that are relatively movable parallel to each other in the supply direction of the supply path. A composite parison forming device, characterized in that the pair of protrusions are engaged with each other to close the corresponding supply passage. 2. In Claim 1, the spout has an annular shape, and one of the two supply paths is
A composite parison forming device having a first cylindrical path connected to the annular spout. 3. The claim 2 according to claim 2, wherein the other one of the two supply paths has a second cylindrical path coaxial with the first cylindrical path. A composite parison forming device, wherein a cylindrical partition member is provided between the cylindrical paths. 4. The cylindrical partition member according to claim 3, wherein the cylindrical partition member is movable along the longitudinal axis thereof, and the first cylindrical path is closed at the first position and the first position. A composite parison forming device, characterized in that the first cylindrical path is opened at a second position spaced apart from. 5. The gap size control mechanism according to claim 1, which controls the size of the gap of the spout to control the thickness of the parison poured out from the spout to a predetermined thickness. A composite parison forming device characterized by having.