JPH0675913B2 - Multilayer blow molding equipment - Google Patents

Description

The present invention relates to a multi-layer blow molding device.

[Prior Art] Conventionally, in the case of manufacturing a multilayer hollow molded container, a multilayer hollow molded container is obtained by extruding a multilayer parison made of a plurality of types of molding materials into a cavity of a molding die and then blow molding. As a method for producing such a multi-layer hollow molded container, for example, there is one disclosed in Japanese Patent Publication No. 55-39448. In the manufacturing method of this publication, a main material supply screw, an adhesive supply screw, and a barrier material supply screw are provided, and the main material from each screw, the adhesive, and the barrier material are respectively Of the main material, the inner layer of the adhesive material, and the outer layer of the barrier material, so that a multi-layer parison is formed in the cavity. Then, by blow molding, the multilayer parison is brought into close contact with the inner surface of the cavity and cooled to obtain a multilayer hollow molded container having a three-kind three-layer structure.

[Problems to be Solved by the Invention] In the manufacturing method of the above publication, when forming a portion that becomes a burr at the tip of the parison, stop extrusion of the barrier material or stop extrusion of the barrier material and the adhesive, The main material and the adhesive or the main material alone are formed. Therefore, since the barrier material is not mixed in the burr generated when the multilayer hollow molded container is manufactured, the burr can be collected and mixed in the main material, and the burr can be reused.

In the manufacturing method of the above publication, burrs are formed from a main material or a main material and an adhesive to reuse the burrs. In this manufacturing method, the burrs are effective parts of the parison when the parison is formed. Therefore, it is desired to reduce the amount of the burr.

It is an object of the present invention to provide a multi-layer blow molding device capable of reducing the amount of burrs made of a main material resin.

"Means for Solving the Problem" The present invention provides a mold for forming a multi-layer parison including an outer layer and an inner layer made of a main material resin, and an intermediate layer made of a sub material resin formed between the outer layer and the inner layer. In a multi-layer blow molding apparatus that extrudes into a cavity of a main material resin and performs blow molding, a control device that controls the extrusion of the main material resin and the sub material resin is provided, and this control device is used in one extrusion cycle of the main material resin. The resin is extruded in two cycles,
In addition, the first extrusion of the secondary resin is started earlier than the extrusion of the primary resin or simultaneously with the extrusion of the primary resin, and the second extrusion of the secondary resin is stopped at the same time as the extrusion of the primary resin is stopped. It is characterized in that it is configured to stop.

[Operation] In the present invention, the control device extrudes the sub-material resin in two cycles in one extrusion cycle of the main-material resin, and extrudes the sub-material resin for the first time from the extrusion of the main-material resin. It is configured to start as soon as possible or at the same time as the extrusion of the main material resin, and to stop the second extrusion of the auxiliary material resin at the same time as the extrusion of the main material resin is stopped. Therefore, a layer of the secondary material resin is formed on the portion corresponding to the burr of the main material resin formed in the previous molding cycle, and the portion corresponding to the burr on which the secondary material resin layer is formed is used as an effective portion of the parison. .

[Examples] Hereinafter, preferred examples of the present invention will be described with reference to the drawings.

FIG. 1 shows the overall structure of a multilayer blow molding device,
FIG. 2 shows a II-II cross section of FIG. 1, and FIG. 3 shows an enlarged main part of the resin passage portion.

In FIGS. 1, 2, and 3, reference numeral 1 is an accumulator head, and a lower half portion of the accumulator head 1 is
A cylinder 2 is provided, and between the outer cylinder 2a of the cylinder 2 and the inner cylinder 2b, a ring piston that can slide up and down along the inner peripheral surface of the outer cylinder 2a and the outer peripheral surface of the inner cylinder 2b. 3 is provided. A core 4 fixed to a cylinder 2 is provided at the center of the accumulator head 1, and a resin reservoir chamber (resin reservoir) 5 is formed by the core 4, the inner cylinder 2b and the ring piston 3. It The resin material storage chamber 5 is supplied with the molten main material resin continuously extruded from the first extruder 6 through an annular communication passage 7. Resin storage chamber 5
The temperature of the main material resin stored therein is adjusted by a temperature adjusting device (not shown) including a heater or the like provided in the cylinder 2.

An annular die 8 is concentrically fixed to the lower end of the cylinder 2, a core support 9 is fixed to the lower end of the core 4, and the die is attached to the lower end of the core support 9. A core 10 which is concentric with 8 is arranged so as to be movable up and down.
The inner peripheral surface of the lower end portion of the die 8 and the outer peripheral surface of the lower end portion of the core 10 are formed in a substantially conical shape, and an annular die slit 11 is formed between them. An annular resin passage 12 is formed between the cylinder 2 and the die 8 and the core support 9 and the core 10, and the die slit 11 communicates with the resin storage chamber 5 through the resin passage 12. ing.

The core 10 is moved up and down by a hydraulic cylinder (not shown) via a rod 13 arranged inside the core 4, whereby a die slit 11 formed between the core 10 and the die 8. Gap is adjusted. Also, the ring piston 3
A first hydraulic cylinder composed of a single-acting hydraulic cylinder via a plunger 14 arranged between the outer cylinder 2a and the inner cylinder 2b.
It is designed to move up and down by the operation of the extrusion cylinder 15, and by the first extrusion cylinder 15 and the ring piston 3,
A first accumulator 16 is configured to pressure-feed the main resin in the resin storage chamber 5 to the die slit 11 via the resin passage 12.

As shown in detail in FIGS. 2 and 3, in the resin passage 12, a hexagonal ring member 17 having a substantially vertical longitudinal section is arranged concentrically with the resin passage 12. The ring member 17 is
The four pillars 18, 18, 18, 18 are supported at a predetermined distance from the inner peripheral surface of the outer cylinder 2a of the cylinder 2, and the ring member 17 and the pillars 18, 18, 18, 18 are circled together. Four pillars 19, 19, 1 provided on the inner core 4 at different positions in the circumferential direction
The resin passage 12 is supported by the outer peripheral surface of the inner core 4 at a predetermined distance by means of 9, 19, and the ring member 17 divides the resin passage 12 into an inner annular passage 12a and an outer annular passage 12b. Inside the ring member 17, an annular auxiliary material resin passage 20 located substantially in the center thereof, and two annular adhesive passages 21 located outside and inside the auxiliary material resin passage 20 in the circumferential direction,
21 and 21 are formed, and these annular passages 20, 21, 21
Respectively communicate with three concentric annular nozzles 24, 25, 25 formed on the lower surface of the ring member 17 via annular slits 22, 23, 23, respectively.

The auxiliary material resin passage 20 includes a ring member 17 and an outer cylinder 2a.
A second extruder 27 provided outside the accumulator head 1 via a passage 26 formed in one column 18 between
Is in communication with. The tip of the second extruder 27, that is, the passage 27
A second accumulator 33 is provided in a. The second accumulator 33 temporarily stores the molten auxiliary material resin extruded from the second extruder 27, and is a second extrusion cylinder 32 formed of a single-acting hydraulic cylinder. The auxiliary material resin is pushed out by the vertical movement of the plunger 28 which is interlocked with. In addition,
The second accumulator 33 is provided with a temperature adjusting device (not shown) for adjusting the temperature of the stored auxiliary material resin.

The adhesive passages 21, 21 are formed by the ring member 17 and the outer cylinder.
It is communicated with a third extruder 30 provided outside the accumulator head 1 through passages 29, 29 formed in one support 18 between the second extruder 2a and the 2a. A third accumulator 31 is provided at the tip of the third extruder 30, that is, the passage 30a. The third accumulator 31 temporarily stores the melted adhesive that is extruded from the third extruder 30 and is a single-acting type. The adhesive is pushed out by the vertical movement of the plunger 34 which is interlocked with the third pushing cylinder 35 which is a hydraulic cylinder. The third accumulator 31 includes a temperature adjusting device (not shown) for adjusting the temperature of the stored adhesive. In addition, the passage 30a is branched at a predetermined position to form the passage 2
Divided into 9 and 29.

The first pushing cylinder 15 of the first accumulator 16 is a hydraulic pressure supply device via an electromagnetic proportional first pressure servo valve 36.
39 and the oil reservoir 36b. Similarly, the second extrusion cylinder 32 of the second accumulator 33 is connected to the hydraulic pressure supply device 39 and the oil reservoir via the electromagnetic proportional second pressure servo valve 37.
37b, and the third pushing cylinder 35 of the third accumulator 31 is further connected to a hydraulic pressure supply device 39 and an oil sump 38b via an electromagnetic proportional third pressure servo valve 38.
The solenoids 36a, 37a, 38a of the first, second and third pressure servo valves 36, 37, 38 are electrically connected to the control device 40 so that the excitation signal is supplied from the control device 40. Has become. With this excitation signal, the solenoids 36a, 37a,
When 38a is excited, the first, second and third pressure servo valves 3
6, 37, 38 are activated and hydraulic pressure is supplied to the first, second and third extrusion cylinders 15, 32, 35, whereby the plunger 1
4, 28, 34 will move up and down.

In order to detect the positions of the plungers 14, 28, 34 of the first, second and third extrusion cylinders 15, 32, 35, the first, second,
First, second and third plunger position detecting devices 41, 42 and 43 are connected to the third pushing cylinders 15, 32 and 35, respectively. The position detection signals from the first, second, and third plunger position detection devices 41, 42, 43 are supplied to the control device 40, and the control device 40 described above with reference to these position detection signals. Control is performed to control the plungers 14, 28, 34 to desired positions.

Next, FIG. 4 shows a state in which the multi-layer parison is being supplied into the cavity of the molding die, and FIG. 5 shows the multi-layer hollow molding container obtained by blow molding.

In FIG. 4, the molding die 44 is composed of left and right dies 45 and 45, and a cavity 46 is formed by both the dies 45 and 45. The reference numerals 47 and 47 denote the cutting parts of the molding die 44.

Then, the molds 45, 45 are opened as shown by the chain line to bring the mold 44 into the mold open state, and the multi-layer parison 48 extruded from the extrusion molding device (see FIG. 1) is placed in the cavity 46 of the mold 44. Place correspondingly. After that, the molds 45, 45 are closed as shown by the solid line to bring the mold 44 into a clamped state, and blow molding is carried out by blowing pressurized air, whereby a multilayer hollow molding container molded into a predetermined shape. 49 is obtained (see FIG. 5).

In FIG. 5, the multi-layer hollow molded container 49 is a main resin outer layer.
50, a main material resin inner layer 51, a sub material resin intermediate layer 52, a connecting agent layer 53 between the main material resin outer layer 50 and the sub material resin intermediate layer 52, and
It is composed of a connecting agent layer 54 between the main material resin inner layer 51 and the sub material resin intermediate layer 52. Reference numerals 55 and 55 represent burrs formed on the outer side of the multilayer hollow molded container 49, and the burrs 5
5, 55 are separated from the multi-layer hollow molded container 49.

Next, FIG. 6 is a timing chart showing a state where the main material resin, the adhesive, and the auxiliary material resin are extruded by the multilayer blow molding apparatus according to the embodiment of the present invention. Extrusion control of adhesive, adhesive, and secondary resin
This is performed by the control device 40 (see FIG. 1).

In FIG. 6, in one extrusion cycle of the main material resin, the extrusion of the adhesive and the auxiliary material resin is divided into two cycles, and the first cycle of each of them is started earlier than the extrusion of the main material resin. And the second cycle of extrusion of the adhesive and auxiliary material resin is
It is stopped at the same time as one cycle of extrusion. That is, at time t1, the extrusion of the adhesive and the auxiliary resin is started, and the time is delayed by time ΔT1 from time t1.
At t2, the extrusion of the main material resin is started, and at time t3, the extrusion of the first cycle of the adhesive and the auxiliary material resin is stopped, and after an interval of ΔT2, again at time t4, The extrusion of the second cycle of the adhesive and the auxiliary material resin is started, and at time t5, the extrusion of the second cycle of the adhesive and the auxiliary material resin and the extrusion of the main material resin are stopped. After that, at time t6, the extrusion of the adhesive and the auxiliary material resin is started, and from time t7 to t10, and thereafter, the extrusion cycle of the main material resin, the adhesive, and the auxiliary material resin is repeated as described above.

The effective part of the parison in the time chart of the above-mentioned thematic chart 6 is from time t4 to time t8, and it is in Bali between time t3 to time t4 consisting of the main resin and from time t8 to time t9. Equivalent to.

Therefore, the time chart of FIG. 6 will be described in comparison with the resin extrusion state diagrams shown in FIGS. 7A and 7B.

Main resin, adhesive, in a parison molding cycle
The extruded state of the secondary resin is shown in FIG. 7A. First, the portion corresponding to L1 of the effective portion L5 of the parison corresponds to time t1 to time t3 in FIG. 6, and the portion corresponding to L2 of the burr portion made of only the main material resin is time t3 to time t4 ( ΔT2) (the line L indicates the boundary between the die side and the molding die). Furthermore, the part corresponding to L3 is from time t4 in FIG.
The parison is formed at L5, which corresponds to time t5.

Figure 7B shows the extruded state of the main resin, adhesive, and auxiliary resin in the next molding cycle, and the portion corresponding to L3 in Figure 7A is located at L31 in the figure and the die side in Figure 7A. The main part of the resin is L4, but the lower part of L31 is L41.
Located in.

Hereinafter, similarly, the parison is sequentially molded in the time chart shown in FIG.

Here, the extrusion of the adhesive and the auxiliary material resin is performed by
Explaining the implications of starting the extrusion of the main resin earlier than the extrusion of the main resin (corresponding to ΔT1 shown in FIG. 6) in one extrusion cycle, in the parison molding process, as shown in FIG. The part corresponding to the burr consisting of L4 (L41)
In order to reduce as much as possible, the extrusion cycle of the main material resin, the adhesive, and the auxiliary material resin of this embodiment is set as shown in FIG. 6, but from the state of FIG. 7A to the state of FIG. 7B. When the main material resin, the adhesive, and the auxiliary material resin are extruded at the same time, the layers of the auxiliary material resin and the adhesive that are extruded are the auxiliary material resin and the adhesive layer below the ring member 17 in the previous cycle. It is because there is a possibility that a defective parison may be molded without continuously connecting to, and by extruding the auxiliary material resin and the adhesive at the same time prior to the main material resin, the layers of the auxiliary material resin and the adhesive material are continuous. Connected to each other. At this time, a layer of the main material resin is continuously formed around the layer of the auxiliary material resin and the adhesive.

Therefore, in this embodiment, it is possible to mold a good quality parison and reduce burrs made of the main resin.

Since the burr-corresponding portion is made of the main resin, it is collected and reused.

In addition, FIG. 8 shows a cross section of a multilayer hollow molding container obtained by the multilayer blow molding apparatus according to the embodiment of the present invention. In FIG. 8, burrs, 57 and 56 are formed from the main resin. Has been formed.

Further, in the present invention, each extrusion cycle of the main material resin (time
t2 to t5), (time t7 to time t10), the start time of the first extrusion of the secondary resin and the adhesive (corresponding to t1 and t6 in FIG. 6).
Is the start time of extrusion of the main resin (equivalent to t2 and t7 in Fig. 6)
It may be set at the same time.

[Advantage of the Invention] As described above, according to the present invention, the control device controls the secondary material resin to be 2 times in one extrusion cycle of the primary material resin.
Extruding in two cycles and disclosing the first extrusion of the secondary material resin earlier than the extrusion of the primary resin or simultaneously with the extrusion of the primary resin, and the second extrusion of the secondary resin is the primary resin Is configured to be stopped at the same time as the extrusion is stopped. Therefore, the secondary material resin can be formed up to the vicinity of the boundary between the die side and the molding die of the portion corresponding to the burr of the main material resin formed in the previous molding cycle. Used as the effective part of. Therefore, it is possible to reduce the amount of burrs composed of the main resin on the lower side of the parison in the next molding cycle.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the overall structure of a multi-layer blow molding device, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. FIG. 5 is a cross-sectional view showing a state in which the multi-layer parison is supplied into the cavity of the molding die, FIG. 5 is a cross-sectional view of the multi-layer hollow molding container obtained by blow molding, and FIG. 6 is an embodiment of the present invention. Timing chart showing the state of extruding the main material resin, the adhesive, and the auxiliary material resin by the multi-layer blow molding apparatus according to, 7A, 7B, the main material resin, the adhesive by the multi-layer blow molding apparatus according to the embodiment of the present invention FIG. 8 is an explanatory view showing a state in which the auxiliary material resin is extruded, and FIG. 8 is a cross-sectional view of a multi-layer blow molding container obtained by the multi-layer blow molding apparatus according to the embodiment of the present invention. 1 ... Accumulator head, 2 ... Cylinder, 2a ... Outer cylinder, 2b ... Inner cylinder, 3 ... Ring piston, 4 ... Core, 5 ... Resin storage chamber, 6 ... First extruder, 7-annular communication passage, 8-annular die, 9-core support, 10-core, 11-die slit, 12-resin passage, 12a-inner annular passage, 12b-outer Annular passage, 13 ... Rod, 14 ... Plunger, 15 ... First extrusion cylinder, 18, 18, 18, 18 ... Strut, 19, 19, 19, 19 ... Strut, 20 ... Annular sub Material-resin passage, 21, 21 ... annular adhesive passage, 22, 23, 23 ... annular slit, 24, 25, 25 ... annular nozzle, 26 ... passage, 27 ... second extruder, 27a ... passage, 28 ... plunger, 29, 29 ... passage, 30 ... third extruder, 30a ... passage, 31 ... third accumulator, 32 ... second extrusion Linda, 33 ... second accumulator, 34 ... plunger, 35 ... third extrusion cylinder, 36, 37, 38 ... first, second, third pressure servo valve, 36a, 37a, 38a ... solenoid, 36b, 37b, 38b ... Oil sump, 39 ... Hydraulic pressure supply device, 40 ... Control device, 41, 42, 43 ... First, second and third plunger position detection device, 44 ... Mold, 45 , 45 …… Left and right mold, 46 …… Cavity, 47, 47 …… Die cutting part of mold, 48 …… Multi-layer parison, 49 …… Multi-layer hollow molding container, 50 …… Main resin outer layer, 51… … Main material resin inner layer, 52 …… Secondary material resin intermediate layer, 53,54 …… Adhesive layer, 55,55 …… Burr, 56,57 …… Burr.

Claims (1)

[Claims] 1. A multi-layer parison composed of an outer layer and an inner layer made of a main material resin and an intermediate layer made of a sub material resin formed between the outer layer and the inner layer is extruded into a cavity of a molding die for blow molding. In the multi-layer blow molding apparatus to be performed, a control device for controlling the extrusion of the main material resin and the sub material resin is provided, and this control device divides the sub material resin into two cycles in one extrusion cycle of the main material resin. Start the extrusion and the first extrusion of the auxiliary material resin earlier than the extrusion of the main material resin or at the same time as the extrusion of the main material resin, and stop the second extrusion of the auxiliary material resin from the extrusion of the main material resin. A multilayer blow molding device characterized in that it is configured to stop at the same time.